WO2014203298A1 - Radio communication method, radio communication system, radio station, and radio terminal - Google Patents

Radio communication method, radio communication system, radio station, and radio terminal Download PDF

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Publication number
WO2014203298A1
WO2014203298A1 PCT/JP2013/003910 JP2013003910W WO2014203298A1 WO 2014203298 A1 WO2014203298 A1 WO 2014203298A1 JP 2013003910 W JP2013003910 W JP 2013003910W WO 2014203298 A1 WO2014203298 A1 WO 2014203298A1
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WO
WIPO (PCT)
Prior art keywords
radio
wireless
virtual cell
connection
communication
Prior art date
Application number
PCT/JP2013/003910
Other languages
French (fr)
Japanese (ja)
Inventor
直之 齋藤
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富士通株式会社
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Publication date
Application filed by 富士通株式会社 filed Critical 富士通株式会社
Priority to PCT/JP2013/003910 priority Critical patent/WO2014203298A1/en
Publication of WO2014203298A1 publication Critical patent/WO2014203298A1/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H04W48/20—Selecting an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W48/00—Access restriction; Network selection; Access point selection
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W60/00—Affiliation to network, e.g. registration; Terminating affiliation with the network, e.g. de-registration
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W76/00—Connection management
    • H04W76/10—Connection setup

Definitions

  • the present invention relates to a wireless communication method, a wireless communication system, a wireless station, and a wireless terminal.
  • next-generation wireless communication technologies have been discussed in order to further increase the speed and capacity of wireless communication in wireless communication systems such as mobile phone systems.
  • 3GPP 3rd Generation Partnership Project
  • LTE Long Term Evolution
  • LTE-A LTE-Advanced
  • Heterogeneous Network HetNet
  • Carrier Aggregation CA
  • CA Carrier Aggregation
  • the communication mode can be variously changed for each wireless terminal depending on the network configuration and the communication status.
  • there may be many communication points capable of CoMP communication and the number and combination of communication points actually used for signal transmission in CoMP communication vary.
  • the number and combination of different types of communication networks and the number and combination of connectable radio frequency carriers are expected to vary.
  • the communication mode is not switched efficiently, the communication performance may be prevented from improving.
  • the disclosed technology has been made in view of the above, and an object thereof is to provide a wireless communication method, a wireless communication system, a wireless station, and a wireless terminal that can efficiently switch communication modes and improve communication performance. .
  • the wireless communication method disclosed in the present application transmits a connection request for connecting to a virtual cell in which a plurality of cells are combined into one, from the wireless terminal, At least one of the plurality of wireless stations forming the virtual cell receives the connection request and establishes connection between the wireless terminal and the plurality of wireless stations forming the virtual cell.
  • FIG. 1 is a diagram illustrating a configuration of a wireless communication system according to the first embodiment.
  • FIG. 2 is a block diagram showing the configuration of the radio station according to the first embodiment.
  • FIG. 3 is a block diagram showing the configuration of the wireless terminal according to the first embodiment.
  • FIG. 4 is a diagram illustrating a hardware configuration of the radio station according to the first embodiment.
  • FIG. 5 is a diagram illustrating a hardware configuration of the wireless terminal according to the first embodiment.
  • FIG. 6 is a sequence diagram for explaining the operation of the wireless communication system according to the first embodiment.
  • FIG. 7 is a diagram for explaining an operation example of the wireless communication system according to the first embodiment.
  • FIG. 8 is a diagram illustrating a configuration of a wireless communication system according to the second embodiment.
  • FIG. 1 is a diagram illustrating a configuration of a wireless communication system according to the first embodiment.
  • FIG. 2 is a block diagram showing the configuration of the radio station according to the first embodiment.
  • FIG. 3 is a block
  • FIG. 9 is a block diagram showing a configuration of a radio station according to the second embodiment.
  • FIG. 10 is a block diagram illustrating a configuration of a wireless terminal according to the second embodiment.
  • FIG. 11 is a diagram illustrating an operation related to the operation of the wireless communication system according to the second embodiment.
  • FIG. 12 is a diagram illustrating an example of a RACH resource related to the description of FIG.
  • FIG. 13 is a sequence diagram for explaining the operation of the radio communication system according to the second embodiment.
  • FIG. 14 is a diagram for explaining an example of the configuration information of the virtual cell of the wireless communication system according to the second embodiment.
  • FIG. 15 is a diagram illustrating an example of a RACH resource related to the description of FIG. FIG.
  • FIG. 16 is a diagram for explaining an operation example of the wireless communication system according to the second embodiment.
  • FIG. 17 is a diagram for explaining determination conditions for establishing a connection in the wireless communication system according to the second embodiment.
  • FIG. 18 is a sequence diagram for explaining the operation of the wireless communication system according to the third embodiment.
  • FIG. 1 shows a configuration of a wireless communication system 1 according to the first embodiment.
  • the radio communication system 1 includes radio stations 10A to 10B and a radio terminal 20.
  • Each of the radio stations 10A to 10B has an antenna and corresponds to a communication point.
  • the communication point corresponds to, for example, a wireless access point, a base station, a communication unit, an antenna, or a cell formed by these.
  • the radio station 10A forms a cell C10A
  • the radio station 10B forms a cell C10B.
  • the wireless stations 10A to 10B communicate with each other through a wired connection or a wireless connection. Further, the radio stations 10A to 10B can perform CoMP communication with the radio terminal 20. For example, in downlink CoMP communication with the radio terminal 20, one or more communication points selected as a set to be used in downlink CoMP communication among the radio stations 10A to 10B are transmitted to the radio terminal 20 from the same time and frequency. The combined transmission is performed to transmit data using the wireless resources. Further, for example, in uplink CoMP communication with the radio terminal 20, data from the radio terminal 20 is transmitted at one or more communication points selected as a set to be used for uplink CoMP communication among the radio stations 10A to 10B. Each reception is performed, and the combined reception is performed in which the received signals are combined between the communication points.
  • the radio stations 10A to 10B are each connected to the network device 3 via a wired connection or a wireless connection, and the network device 3 is connected to the network 2 via a wired connection or a wireless connection.
  • the radio stations 10A to 10B are provided so as to be able to transmit and receive data and control information via the network device 3 and the network 2.
  • FIG. 2 is a block diagram showing a functional configuration of the radio station 10A.
  • the radio station 10A includes a reception unit 11, a transmission unit 12, and a control unit 13. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
  • the functional configuration and hardware configuration of the radio station 10B are the same as the functional configuration and hardware configuration of the radio station 10A. In the following description, it is assumed that the wireless terminal 20 exists in the cell C10A formed by the wireless station 10A and synchronizes with the wireless station 10A when communication is started.
  • the receiving unit 11 receives a data signal and a control signal via an antenna.
  • the reception unit 11 receives an uplink signal transmitted on an uplink data channel or a control channel.
  • An example of the uplink data channel is an individual data channel.
  • examples of the uplink control channel include a random access channel and a dedicated control channel.
  • a signal to be received for example, a connection request for establishing a connection from the radio terminal 20, a signal indicating a communication level at the radio terminal 20, a reference signal used for channel estimation or demodulation (also referred to as a pilot signal).
  • Examples of the connection request include a connection request for connecting to the cell C10A and a connection request for connecting to a virtual cell described later.
  • the transmission unit 12 transmits a data signal and a control signal via an antenna.
  • the antenna may be common for transmission and reception or may be separate.
  • the transmission unit 12 transmits, for example, a downlink signal transmitted on a downlink data channel or control channel.
  • Examples of the downlink data channel include a common data channel and a dedicated data channel.
  • examples of the downlink control channel include a synchronization channel, a broadcast channel, a common control channel, and an individual control channel.
  • a signal to be transmitted for example, a signal for informing system information or control information common to cells, a control signal transmitted to the connected wireless terminal 20 on the dedicated control channel, or a dedicated data channel to the connected wireless terminal 20
  • the control signal transmitted above and the data signal transmitted on the dedicated data channel to the connected wireless terminal 20 can be mentioned.
  • Examples of the signal to be transmitted include a paging signal for calling the wireless terminal 20 when a call arrives at the wireless terminal 20 and a control signal for controlling the uplink transmission power from the wireless terminal 20. .
  • a signal to be transmitted for example, a cell-specific reference signal (also referred to as a common pilot signal), a wireless terminal-specific reference signal (also referred to as an individual pilot signal) used for channel estimation or demodulation
  • Configuration information indicating radio resources prepared for transmission of these reference signals is included.
  • the signal to be transmitted includes a signal indicating the communication level at the radio stations 10A to 10B and a response signal to the signal for establishing a connection from the radio terminal 20.
  • the signal to be transmitted includes configuration information of cell C10A (connection information for connection to cell C10A) and configuration information of peripheral cell C10B of cell C10A (connection information for connection to cell C10B).
  • Such configuration information may be broadcast as, for example, system information or control information common to cells.
  • the connection information for connecting to the cell C10A includes, for example, identification information for identifying the cell C10A.
  • the connection information for connecting to the cell C10B includes, for example, identification information for identifying the cell C10B.
  • the signal to be transmitted includes virtual cell configuration information (connection information for connecting to the virtual cell).
  • the virtual cell is a cell in which a plurality of cells are combined into one.
  • the virtual cell may be referred to as a multi-cell or a group cell, for example.
  • a virtual cell may be called a logical cell with respect to the physical cell corresponding to each radio station, for example.
  • the virtual cell is formed so as to cover at least a part of each of the plurality of cells.
  • the virtual cell configuration information may be broadcasted as system information or common cell control information, for example. Further, for example, the configuration information of the virtual cell may be stored and transmitted in an area prepared in advance in the format of the system information or the control information common to the cells, or may be transmitted in a predetermined control timing or in a predetermined area. The data may be stored and transmitted according to the period.
  • the connection information for connecting to the virtual cell includes, for example, identification information for identifying the virtual cell.
  • the identification information for identifying the virtual cell includes, for example, a plurality of cell identification information for identifying each of the plurality of cells included in the virtual cell.
  • the connection information for connecting to the virtual cell includes, for example, radio resource allocation for transmitting a connection request for connecting to the virtual cell, connection request configuration information for connecting to the virtual cell, virtual cell A determination condition for determining whether or not to connect to may be included.
  • the allocation of radio resources indicates, for example, the arrangement of resource elements (also referred to as time frequency resources) used for connection requests.
  • the connection request for connecting to the virtual cell is transmitted from the wireless terminal 20 as at least one of random access at the time of initial connection, random access at the time of reconnection, and random access at the time of handover.
  • a radio resource for transmitting a connection request for connecting to a virtual cell for example, a radio resource prepared for random access can be used. At this time, for example, a part of radio resources prepared for normal random access is allocated to radio resources for transmitting a connection request for connecting to a virtual cell according to a predetermined control timing or a predetermined period. Also good. Or for example, you may prepare beforehand the radio
  • the control unit 13 transmits / receives data and control information to / from the network device 3 and other wireless stations 10B via a wired connection or a wireless connection.
  • the control unit 13 inputs received data and control information from the reception unit 11. Further, the control unit 13 outputs data to be transmitted and control information to the transmission unit 12.
  • the control unit 13 transmits and receives data and control information via a wired network via a communication interface.
  • the control unit 13 performs management such as access management with the wireless terminal 20 and allocation of wireless resources to the wireless terminal 20.
  • control unit 13 exchanges information with the peripheral radio station 10B and sets the configuration information of the virtual cell.
  • control unit 13 sets possible configuration information of one or a plurality of virtual cells based on the cell arrangement, the wireless communication scheme used in each cell, the radio frequency carrier used in each cell, and the like.
  • control unit 13 includes, for example, the number of wireless terminals connected to the wireless station 10A, the communication level between the wireless station 10A and the connected wireless terminal, the number of wireless terminals connected to the other wireless station 10B, Considering at least one of the communication level between the other wireless station 10B and the connected wireless terminal, the communication mode for transmitting data from the wireless station 10A, and the communication mode for transmitting data from the other wireless station 10B
  • the configuration information of the virtual cell may be set.
  • the communication level between the radio stations 10A to 10B and the radio terminal 20 is measured from, for example, an uplink reference signal or a downlink reference signal.
  • the communication level may be reported from the radio terminal 20, and the communication level between the radio station 10A and the radio terminal 20 is measured by the radio station 10A, and the communication level between the radio station 10B and the radio terminal 20 is measured. May be measured by the radio station 10B and notified to the radio station 10A.
  • Examples of the communication mode include single antenna communication, MIMO communication, and CoMP communication.
  • the MIMO communication includes, for example, MU (Multi-User) -MIMO communication and SU (Single-User) -MIMO communication.
  • the CoMP communication includes, for example, DPS (Dynamic Point Selection) -COMP communication, JT (Joint Transmission) -CoMP communication, and JR (Joint reception) -CoMP communication described later.
  • DPS is a method of dynamically selecting a communication point to be used for transmission among a plurality of communication points.
  • JT is a method for combining (synthesizing) signals transmitted from a plurality of communication points.
  • JR is a method of receiving a signal at each of a plurality of communication points and combining (combining) the communication points.
  • the virtual cell configuration information may be updated at a predetermined control timing, for example. Further, for example, the configuration information of the virtual cell may be selected at a predetermined control timing from candidates for configuration information stored or set in advance.
  • the virtual cell configuration information is commonly used by the radio station 10A and other radio stations around the own station.
  • Other wireless stations around the own station include another wireless station 10B capable of CoMP communication.
  • the virtual cell configuration information may be set by the radio station 10A or the radio station 10B, for example, and other devices on the network device 3 or the network 2 exchange information with the radio stations 10A to 10B. May be set. Also, the virtual cell configuration information may be notified from one of the radio stations 10A to 10B to the other radio station via wired communication or wireless communication. The apparatus may notify the radio stations 10A-B. Further, instead of notifying the virtual cell configuration information itself, information for selecting predetermined virtual cell configuration information from candidates of configuration information stored or set in advance may be notified. Further, the configuration information of the virtual cell may be stored in, for example, the network device 3 or another device on the network 2, and may be acquired by accessing from the radio stations 10A to 10B at a predetermined control timing. Further, instead of notifying the virtual cell configuration information itself, information for accessing the stored virtual cell configuration information may be notified.
  • control part 13 will prepare the connection with the radio
  • the control unit 13 establishes a connection by exchanging control information with the wireless terminal. Similarly, other wireless stations forming the virtual cell also exchange control information with the wireless terminal 20 to establish a connection.
  • FIG. 3 is a functional block diagram showing the configuration of the wireless terminal 20.
  • the wireless terminal 20 includes a reception unit 21, a transmission unit 22, and a control unit 23. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
  • the receiving unit 21 receives data signals and control signals transmitted from the radio stations 10A to 10B via the antenna.
  • a signal to be received for example, a signal for reporting system information and control information common to cells, a control signal transmitted from the connection radio station 10A on the dedicated control channel, and a signal transmitted from the connection radio station 10A on the dedicated data channel Control signals.
  • the received signal includes, for example, a paging signal for calling the wireless terminal 20, a response signal to a signal for establishing a connection from the wireless terminal 20, a signal indicating the communication level at the wireless stations 10A to 10B, And a control signal for controlling uplink transmission power.
  • the received signal includes, for example, a cell-specific reference signal, a reference signal for each wireless terminal used for channel estimation and demodulation, and configuration information indicating a radio resource prepared for transmission of these reference signals.
  • the received signal includes, for example, the configuration information of the cell C10A and the configuration information of the neighboring cell C10B transmitted from the radio station 10A. Further, the signal to be transmitted includes, for example, virtual cell configuration information.
  • the transmission unit 22 transmits a data signal and a control signal via an antenna.
  • the antenna may be common for transmission and reception or may be separate.
  • the transmission unit 22 transmits, for example, an uplink signal transmitted on an uplink data channel or a control channel.
  • Examples of the signal to be transmitted include a connection request for establishing a connection, a signal indicating a communication level at the wireless terminal 20, and a reference signal used for channel estimation and demodulation.
  • Examples of the connection request include a connection request for connecting to the cell C10A and a connection request for connecting to the virtual cell.
  • the control unit 23 inputs received data and control information from the reception unit 21. In addition, data to be transmitted and control information are output to the transmission unit 22. In addition, the control unit 23 performs communication control such as management of access to a radio station and control of transmission power of a transmission signal.
  • the communication control includes, for example, processing for CoMP communication, processing for carrier aggregation, and processing for handover (Inter-Cell, Inter-Frequency, Inter-Rat, etc.).
  • the control unit 23 acquires information indicating a communication state with the radio stations 10A to 10B. Specifically, for example, the control unit 23 detects signals received from the radio stations 10A to 10B, and acquires a communication level. For example, the control unit 23 detects a cell-specific reference signal or a wireless terminal-specific reference signal, and acquires a communication level.
  • the communication level includes, for example, reception power and reception quality.
  • control unit 23 determines whether to connect to the virtual cell. For example, the control unit 23 determines whether to connect to the virtual cell based on the connection information for connecting to the virtual cell and the information indicating the communication state between the plurality of radio stations forming the virtual cell. To do. Specifically, for example, the control unit 23 uses the identification information for identifying the virtual cell to acquire information indicating the communication state with a plurality of radio stations forming the virtual cell, and sets a predetermined determination condition. To determine whether to connect to the virtual cell. When connecting to the virtual cell, the control unit 23 transmits a connection request for connecting to the virtual cell, receives a response signal, performs a procedure for establishing the connection, and establishes a connection with the virtual cell. .
  • FIG. 4 is a diagram illustrating a hardware configuration of the radio station 10A.
  • the radio station 10A includes, as hardware components, an RF (Radio Frequency) circuit 32 including an antenna 31, a CPU (Central Processing Unit) 33, a DSP (Digital Signal Processor) 34, and the like. , A memory 35 and a network IF (Interface) 36.
  • the CPU is connected via a network IF 36 such as a switch so that various signals and data can be input and output.
  • the memory 35 includes at least one of RAM (Random Access Memory) such as SDRAM (Synchronous Dynamic Random Access Memory), ROM (Read Only Memory), and flash memory, and stores programs, control information, and data.
  • the transmission unit 12 and the reception unit 11 are realized by the RF circuit 32 or the antenna 31 and the RF circuit 32, for example.
  • the control unit 13 is realized by, for example, an integrated circuit such as the CPU 33 or an integrated circuit such as the DSP 34.
  • FIG. 5 is a diagram illustrating a hardware configuration of the wireless terminal 20.
  • the wireless terminal 20 includes, as hardware components, an RF circuit 42 including an antenna 41, a CPU 43, and a memory 44, for example.
  • the wireless terminal 20 may have a display device such as an LCD (Liquid Crystal Display) connected to the CPU 43.
  • the memory 44 includes at least one of RAM such as SDRAM, ROM, and flash memory, for example, and stores programs, control information, and data.
  • the transmission unit 22 and the reception unit 21 are realized by the RF circuit 42 or the antenna 41 and the RF circuit 42, for example.
  • the control unit 23 is realized by an integrated circuit such as the CPU 43, for example.
  • FIG. 6 is a sequence diagram for explaining an operation for establishing a connection in the wireless communication system 1
  • FIG. 7 is a diagram for explaining an operation example for establishing a connection in the wireless communication system 1.
  • the wireless stations 10A to 10B are provided so as to be capable of CoMP communication.
  • the radio stations 10A to 10B may use different communication methods.
  • the radio stations 10A to 10B may be radio stations capable of carrier aggregation.
  • the radio terminal 20 exists in a cell C10A formed by the radio station 10A and a C10B formed in the radio station 10B.
  • the communication mode of each communication point is dynamically adjusted at a relatively short cycle so as to increase the allocation by increasing the allocation of radio communication resources to a predetermined radio terminal.
  • the communication mode of each communication point can change variously for every radio
  • there may be many communication points capable of CoMP communication and the number and combination of communication points actually used for signal transmission in CoMP communication vary.
  • the number and combination of different types of communication networks and the number and combination of connectable radio frequency carriers are expected to vary.
  • the operation for establishing a connection is performed as follows.
  • the radio station 10A sets the virtual cell configuration information and notifies the radio station 10B (S1). Specifically, as shown in FIG. 7, a virtual cell VC1 formed by the radio stations 10A to 10B is set.
  • the configuration information of the virtual cell VC1 includes, for example, identification information for identifying the virtual cell VC1, determination conditions for determining whether the wireless terminal 20 requests connection to the virtual cell VC1, and connection to the virtual cell VC1. Including an arrangement of radio resource elements that transmit and receive a connection request.
  • the identification information for identifying the virtual cell VC1 includes identification information of each of the radio stations 10A to 10B forming the virtual cell VC1.
  • the determination condition is, for example, a condition that the communication performance is assumed to be improved by cooperative cooperation between the radio station 10A and the radio station 10B.
  • the reception level from the radio stations 10A to 10B, the reception level from the radio station 10A, and the radio station The relationship with the reception level from 10B is included.
  • the radio stations 10A to 10B transmit the configuration information of the virtual cell VC1 (S2).
  • the configuration information of the virtual cell VC1 is broadcast from the radio stations 10A to 10B as system information or cell-common control information.
  • the wireless terminal 20 determines connection with the virtual cell VC1 (S3). Specifically, the radio terminal 20 measures the reception level of signals from the radio stations 10A to 10B forming the virtual cell VC1 based on the identification information of the virtual cell VC1. Then, whether to make a connection request to the virtual cell VC1 is determined based on the measured reception level and the determination condition set in the configuration information of the virtual cell VC1. In the example of FIG. 7, for example, the reception level from the radio stations 10A to 10B is within a predetermined range, and the difference between the reception level from the radio station 10A and the reception level from the radio station 10B is within the predetermined range. It is determined that a connection request is made to the virtual cell VC1.
  • connection request is made to the virtual cell VC1. For example, when the determination condition for requesting connection to the virtual cell VC1 is not satisfied and the determination condition for requesting connection to the cell C10A is satisfied, the connection to the cell C10A is determined.
  • the wireless terminal 20 transmits a connection request with the virtual cell VC1 (S4).
  • the connection request with the virtual cell VC1 is transmitted using a radio resource element set in the configuration information of the virtual cell VC1.
  • a radio resource element set in the configuration information of the virtual cell VC1.
  • the wireless station 10A that has received the connection request can recognize that it is a connection request to the virtual cell VC1.
  • preparation for connection with the virtual cell VC1 is performed without shifting to establishment of connection to the cell C10A, and shift to communication by cooperative cooperation.
  • the radio stations 10A to 10B receive a connection request with the virtual cell VC1, and prepare for connection between the radio terminal 20 and the virtual cell VC1 (S5). Specifically, for example, the wireless station 10A receives a connection request and notifies the wireless station 10B of information for establishing a connection with the wireless terminal 20 from the wireless station 10A.
  • connection establishment is executed between the wireless terminal 20 and the wireless stations 10A and 10B (S6).
  • connection establishment is executed between the wireless terminal 20 and the wireless stations 10A and 10B (S6).
  • the communication performance is improved by cooperative cooperation between the wireless station 10A and the wireless station 10B, for example, whether or not the cooperative cooperation can be performed after the wireless terminal 20 establishes an initial connection with one wireless station 10A.
  • communication by cooperative cooperation can be started quickly. That is, switching to cooperative cooperation is performed efficiently.
  • the wireless communication system 1 it is possible to efficiently switch the communication mode between the wireless terminal 20 and the wireless stations 10A to 10B and improve the communication performance.
  • the radio terminal 20 receives information for connecting to the virtual cell from the other radio stations in synchronization with the other radio stations of the radio communication system 1, and is formed by the radio stations 10A to 10B.
  • the connection establishment with the virtual cell to be performed may be executed.
  • the wireless communication system 1 has two wireless stations, but the number of wireless stations is arbitrary. Also, a radio station capable of CoMP communication and a radio station not capable of CoMP communication may be mixed. Further, a radio station capable of performing a carrier aggregation operation and a radio station not capable of performing a carrier aggregation operation may be mixed. Further, radio stations using different types of communication methods may be mixed.
  • the wireless communication system 1 has one wireless terminal, but the number of wireless terminals is arbitrary. Also, wireless terminals capable of CoMP communication and wireless terminals not capable of CoMP communication may be mixed. In addition, wireless terminals that can perform carrier aggregation operations and wireless terminals that cannot perform carrier aggregation operations may be mixed. Also, wireless terminals that can communicate with different types of communication methods and wireless terminals that are not capable of communicating may be mixed.
  • the wireless communication system 1A according to the second embodiment has wireless stations 50A to 50C shown in FIG. 9 described later instead of the wireless stations 10A to 10B, and instead of the wireless terminal 20, Wireless terminals 70A to 70C (also referred to as UE # 1 to UE3) shown in FIG.
  • the overall configuration of a wireless communication system 1A according to the second embodiment is the same as that of the wireless communication system 1 shown in FIG.
  • each of the wireless stations 50A to 50C is connected to the network device 3 via a wired connection or a wireless connection, and the network device 3 is connected to the network 2 via a wired connection or a wireless connection.
  • the radio stations 50A to 50C are provided so as to be able to transmit and receive data and control information via the network device 3 and the network 2.
  • each of the radio stations 50A to 50C has an antenna and corresponds to a communication point.
  • Radio stations 50A-C form cells C50A-C, respectively.
  • the radio stations 50A to 50C communicate with each other via a wired connection or a wireless connection.
  • the radio stations 50A to 50C can perform CoMP communication with the radio terminals UE # 1 to UE # 3.
  • the radio terminal UE # 1 exists in the cell C50A formed by the radio station 50A
  • the radio terminal UE # 2 exists in the cells C50A and B formed by the radio stations 50A and B
  • the radio terminal UE # 3. Exists in the cell C50B formed by the radio station 50B.
  • FIG. 9 is a block diagram showing a functional configuration of the radio station 50A of the radio communication system 1A according to the second embodiment.
  • the functional configuration and hardware configuration of the radio stations 50B to 50C are the same as the functional configuration and hardware configuration of the radio station 50A.
  • the radio station 50A includes a reception antenna 51, a reception RF unit 52, an FFT (Fast Fourier Transform) unit 53, a physical channel separation unit 54, a signal demodulation unit 55, and a channel estimation unit 56.
  • Unit 63 transmission RF unit 64, and transmission antenna 65.
  • the reception antenna 51 receives a radio signal and outputs it to the reception RF unit 52.
  • the reception antenna 51 includes, for example, a plurality of antennas (physical antennas).
  • the reception antenna 51 may be configured to be shared with the transmission antenna 65 and switched between transmission and reception by a transmission / reception switching unit or the like.
  • the reception antenna 51 receives, for example, an uplink signal (data signal or control signal) transmitted on an uplink data channel or control channel. Examples of the physical channel that receives the signal include PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel).
  • PRACH Physical Random Access Channel
  • PUSCH Physical Uplink Shared Channel
  • PUCCH Physical Uplink Control Channel
  • Examples of received signals include RACH (Random Access Channel) signals for establishing connections from the radio terminals UE # 1 to UE3 and signals indicating reception levels at the radio terminals UE # 1 to UE3 (for example, RSRP Report). ) And reference signals for channel estimation and demodulation.
  • RACH Random Access Channel
  • the reception RF unit 52 performs processing such as A / D (Analog-to-Digital) conversion on the received signal.
  • the FFT unit 53 performs FFT processing on the digital signal.
  • the physical channel separation unit 54 separates each channel signal from the FFT-processed signal.
  • the physical channel separation unit 54 extracts an uplink reference signal included in the uplink signal.
  • the uplink reference signal includes, for example, SRS (Sounding Reference Signal) used for channel estimation for each uplink frequency and DM-RS (DeModulation RS) for demodulation of the uplink signal.
  • the signal demodulator 55 demodulates the signal of each separated channel based on control information notified or stored in advance or a reference signal for demodulation.
  • the channel estimation unit 56 acquires a channel estimation value indicating a channel propagation state based on control information notified or stored in advance or a received reference signal.
  • the demodulated signal is decoded based on the channel estimation value.
  • the data signal and control signal acquired through the decoding process are output to the communication control unit 58. Further, ACK (ACKnowledgement) / NACK (Negative ACKnowledgement) is output to the communication control unit 58 as a decoding result of the data signal.
  • the reception level measurement unit 57 measures the reception level (uplink reception power and uplink reception quality) from the received signal. Examples of the reception level include RSRP, RSRQ, SIR, SINR, and the like.
  • the communication control unit 58 transmits / receives data and control information to / from the network device and other wireless stations via a wired connection or a wireless connection. Further, the communication control unit 58 performs communication control such as management of access to the radio terminals UE # 1 to UE # 3 and control of transmission power for transmitting signals.
  • the transmission power is controlled by, for example, open loop control that compensates for a propagation loss (path loss) between communication points, adaptive modulation control, and closed loop control using a TPC (Transmission Power Control) command.
  • the communication control includes, for example, processing for CoMP communication, processing for carrier aggregation, and processing for handover (Inter-Cell, Inter-Frequency, Inter-Rat, etc.). The details of the communication control unit 58 will be described later.
  • the upper layer data processing unit 59 performs reordering processing of the decoded data signal and acquires uplink user data. Further, the upper layer data processing unit 59 processes downlink user data acquired from a network device or another wireless station and control information to be transmitted to generate a transmission packet.
  • the signal generator 60 encodes and modulates the transmission packet and outputs it to the physical channel multiplexer 62.
  • the signal generation unit 60 generates a control signal transmitted on the dedicated control channel and outputs the control signal to the physical channel multiplexing unit 62.
  • the reference signal generator 61 generates a downlink reference signal and outputs it to the physical channel multiplexer 62.
  • the downlink reference signal is a radio terminal used for downlink cell-specific CRS (Cell-specific Reference Signal), downlink CSI-RS (Channel State Information Reference Signal), downlink channel estimation and signal demodulation, for example. Includes an individual reference signal (DM-RS).
  • the CRS is used for measurement of downlink communication quality and demodulation of downlink signals, and is set in association with cell identification information (cell ID).
  • CSI-RS is used for measurement of downlink communication quality, and can be set for each communication point, for example.
  • the physical channel multiplexing unit 62 allocates the encoded / modulated transmission packet, control signal, and reference signal to the physical channel radio resource according to the scheduling of the communication control unit 58.
  • the IFFT unit 63 performs IFFT processing on the multiplexed signal.
  • the transmission RF unit 64 performs D / A conversion, distortion compensation processing, amplification processing, and the like on the signal after IFFT processing and outputs the result to the transmission antenna 65.
  • the transmission antenna 65 transmits a radio signal input from the transmission RF unit 64.
  • the transmission antenna 65 includes, for example, a plurality of antennas.
  • the transmission antenna 65 transmits, for example, a downlink signal (data signal or control signal) transmitted on a downlink data channel or control channel.
  • Examples of physical channels that transmit signals include broadcast channels PBCH (Physical road Broadcast Channel), PMCH (Physical Multicast Channel), shared channel PDSCH (Physical Downlink Shared Channel), dedicated control channel PDCCH (Physical Downlink Control Channel), and the like.
  • E-PDCCH Enhanced--Physical-Downlink-Control-Channel).
  • a signal to be transmitted for example, when a call arrives at the radio terminals UE # 1 to UE # 3, a PCH (Paging Channel) signal for calling the radio terminals UE # 1 to UE3, or a response signal to the RACH signal ( RAR, Random Access Response).
  • the signal to be transmitted include a signal indicating the reception level at the radio station 50A, and a control signal (for example, downlink transmission power information, a TPC command, etc.) for controlling the uplink transmission power.
  • the signal to be transmitted is, for example, a reference signal for each wireless terminal used for channel estimation or demodulation, a plurality of configuration information indicating a radio resource prepared for transmission of a reference signal for each wireless terminal, or a plurality of configurations
  • Each of the information includes a signal that specifies a use mode related to use of the radio resource indicated by the information.
  • Examples of the control signal include L1 / L2 signaling transmitted on the dedicated wireless channel to the connected wireless terminal and RRC (Radio Resource Control) signaling transmitted on the shared channel to the connected wireless terminal.
  • the control signal includes, for example, system information that is stored in MIB (Master Information Block) or SIB (System Information Block) and transmitted on a broadcast channel or a shared channel designated by the broadcast channel.
  • the communication control unit 58 performs management of access to the radio terminals UE # 1 to UE3 and scheduling of allocation of radio resources to the radio terminals UE # 1 to UE3.
  • the communication control unit 58 exchanges information with the peripheral radio stations 50B to 50C, for example, and sets the virtual cell configuration information.
  • the communication control unit 58 sets configuration information of one or a plurality of virtual cells that can be taken based on, for example, the cell arrangement, the radio communication scheme used in each cell, the radio frequency carrier used in each cell, and the like. .
  • the communication control unit 58 also transmits, for example, the number of wireless terminals to which the wireless stations 50A to 50C are connected, the communication level between the wireless stations 50A to 50C and the connected wireless terminals, and data transmitted from the wireless stations 50A to 50C.
  • the configuration information of the virtual cell may be set in consideration of at least one of the communication modes to be performed.
  • the communication level between the radio stations 50A to 50C and the radio terminals UE # 1 to UE # 3 is measured from, for example, an uplink reference signal or a downlink reference signal.
  • the communication level may be reported from the radio terminals UE # 1 to UE # 3, for example.
  • the communication level between the radio station 50A and the radio terminals UE # 1 to 3 is measured by the radio station 50A, and the communication level between the radio station 50B and the radio terminals UE # 1 to UE3 is measured. May be measured by the radio station 50B, the communication level between the radio station 50C and the radio terminals UE # 1 to UE # 3 may be measured by the radio station 50C, and notified from the radio stations 50B to 50A to the radio station 50A.
  • Examples of the communication mode include single antenna communication, MIMO communication, and CoMP communication.
  • the virtual cell configuration information may be updated at a predetermined control timing, for example. Further, for example, the configuration information of the virtual cell may be selected at a predetermined control timing from candidates for configuration information stored or set in advance.
  • the virtual cell configuration information is commonly used by the radio station 50A and other radio stations around the own station.
  • Other radio stations in the vicinity of the own station include other radio stations 50B to 50C capable of CoMP communication.
  • the configuration information of the virtual cell may be set by the radio station 50A or may be set by the radio stations 50B to C, and other devices on the network device 3 or the network 2 may exchange information with the radio stations 50A to 50C. You may set by exchanging. Further, the configuration information of the virtual cell may be notified from one of the radio stations 50A to 50C to another radio station via wired communication or wireless communication. May be notified to the radio stations 50A to 50C. Further, instead of notifying the virtual cell configuration information itself, information for selecting predetermined virtual cell configuration information from candidates of configuration information stored or set in advance may be notified.
  • the configuration information of the virtual cell may be stored in, for example, the network device 3 or another device on the network 2 and may be obtained by accessing from the radio stations 50A to 50C at a predetermined control timing. Further, instead of notifying the virtual cell configuration information itself, information for accessing the stored virtual cell configuration information may be notified.
  • the communication control part 58 will prepare the connection with radio
  • the communication control unit 58 establishes a connection by exchanging control information with the wireless terminal. Similarly, other radio stations forming the virtual cell also exchange control information with the radio terminals UE # 1 to UE # 3 to establish a connection.
  • FIG. 10 is a block diagram showing a functional configuration of the wireless terminal 70A of the second embodiment.
  • the radio terminal 70A includes a reception antenna 71, a reception RF unit 72, an FFT unit 73, a physical channel separation unit 74, a signal demodulation unit 75, a channel estimation unit 76, and a reception level measurement.
  • the functional configuration and hardware configuration of the wireless terminals 70B to 70C are the same as the functional configuration and hardware configuration of the wireless terminal 70A.
  • the reception antenna 71 receives a radio signal and outputs it to the reception RF unit 72.
  • the reception antenna 71 includes, for example, a plurality of antennas.
  • the reception antenna 71 may be configured to be shared with the transmission antenna 85 and switched between transmission and reception by a transmission / reception switching unit or the like.
  • the reception antenna 71 receives, for example, an uplink signal (data signal or control signal) transmitted on an uplink data channel or control channel. Examples of the received signal include a PCH signal for calling the wireless terminal 70A when a call arrives at the wireless terminal 70A, and a response signal to the RACH signal from the wireless terminal 70A.
  • examples of the received signal include a signal indicating the reception level at the radio stations 50A to 50C, and a control signal for controlling uplink transmission power (for example, downlink transmission power information, TPC command, etc.).
  • the received signal includes, for example, a reference signal for each wireless terminal used for channel estimation and demodulation, and configuration information indicating a wireless resource prepared for reference signal transmission.
  • the signal to be transmitted includes configuration information of the cell C50A (connection information for connecting to the cell C50A) and configuration information of the peripheral cells C50B to C of the cell C50A (connection information for connecting to the cells C50B to C).
  • the connection information for connecting to the cells C50A-C includes, for example, identification information for identifying the cells C50A-C.
  • the signal to be transmitted includes virtual cell configuration information (connection information for connecting to the virtual cell).
  • the connection information for connecting to the virtual cell includes, for example, identification information for identifying the virtual cell.
  • the identification information for identifying the virtual cell includes, for example, a plurality of cell identification information for identifying each of the plurality of cells forming the virtual cell. Specifically, identification information for identifying a virtual cell is indicated by, for example, a combination (list) of PCI (Physical Cell ID) for identifying each of a plurality of cells forming the virtual cell. It is.
  • the connection information for connecting to the virtual cell includes, for example, radio resource allocation for transmitting a connection request for connecting to the virtual cell, connection request configuration information for connecting to the virtual cell, virtual cell The determination condition for determining whether to connect to is included.
  • control signal examples include L1 / L2 signaling transmitted on the dedicated control channel from the connection radio station 50A and RRC signaling transmitted on the shared channel from the connection radio station 50A.
  • the control signal includes, for example, system information stored in MIB or SIB and transmitted on a broadcast channel or a shared channel designated by the broadcast channel.
  • the reception RF unit 72 performs processing such as A / D conversion on the received signal.
  • the FFT unit 73 performs FFT processing on the digital signal.
  • the physical channel separation unit 74 separates each channel signal from the FFT-processed signal. For example, the physical channel separation unit 74 obtains a subcarrier signal from a received OFDM (Orthogonal Frequency Division Multiplexing) signal.
  • the signal demodulator 75 demodulates the signal of each separated channel based on control information notified or stored in advance or a reference signal specific to each radio terminal for demodulation.
  • the channel estimation unit 76 acquires a channel estimation value indicating a channel propagation state based on control information notified or stored in advance or the received reference signal for each wireless terminal.
  • the demodulated signal is decoded based on the channel estimation value.
  • the user data and control information acquired through the decryption process are output to the communication control unit 78. Further, ACK / NACK is output to the communication control unit 78 as a decoding result of the data signal.
  • the reception level measuring unit 77 measures the reception level (downlink reception power and downlink reception quality) from the received signal.
  • reception levels include RSRP, RSRQ, SIR, SINR, and the like.
  • the signals used include, for example, cell-specific reference signals.
  • the communication control unit 78 performs communication control such as access management with the radio stations 50A to 50C and control of transmission power for transmitting signals.
  • the transmission power is controlled by, for example, open loop control that compensates for propagation loss (path loss) between communication points, adaptive modulation control, and closed loop control using a TPC command.
  • the communication control includes, for example, processing for CoMP communication, processing for carrier aggregation, and processing for handover (Inter-Cell, Inter-Frequency, Inter-Rat, etc.).
  • the upper layer data processing unit 79 performs a reordering process on the decoded data signal and acquires the downlink user data. Further, the upper layer data processing unit 79 processes uplink user data and control information to be transmitted, and generates a transmission packet.
  • the signal generation unit 80 encodes and modulates the transmission packet, adjusts the amplitude based on the uplink transmission power information, and outputs it to the physical channel multiplexing unit 82.
  • the reference signal generation unit 81 generates an uplink reference signal and outputs it to the physical channel multiplexing unit 82.
  • the physical channel multiplexing unit 82 assigns the encoded and modulated transmission packet and reference signal to the physical channel radio resource.
  • the IFFT unit 83 performs IFFT processing on the multiplexed signal.
  • the transmission RF unit 84 performs D / A conversion, distortion compensation processing, amplification processing, and the like on the signal after IFFT processing, and outputs the result to the transmission antenna 85.
  • the transmission antenna 85 transmits a radio signal input from the transmission RF unit 84.
  • the transmission antenna 85 includes, for example, a plurality of antennas.
  • the transmission antenna 85 transmits, for example, an uplink signal (data signal or control signal) transmitted on an uplink data channel or control channel.
  • the transmitted signal includes, for example, a RACH signal for establishing a connection, a signal indicating a reception level at the radio terminal 70A, and a reference signal for channel estimation and demodulation.
  • the communication control unit 78 determines whether or not to connect to the virtual cell. For example, the communication control unit 78 determines whether to connect to the virtual cell based on the connection information for connecting to the virtual cell and the information indicating the communication state between the plurality of radio stations forming the virtual cell. decide. Specifically, for example, the communication control unit 78 uses the identification information for identifying the virtual cell to acquire information indicating the communication state with a plurality of radio stations forming the virtual cell, and the predetermined determination condition Is used to determine whether or not to connect to the virtual cell. Then, when connecting to the virtual cell, the communication control unit 78 transmits a connection request for connecting to the virtual cell, receives a response signal, performs a procedure for establishing the connection, and establishes a connection with the virtual cell. To do.
  • the hardware configuration of the radio station 50A in the radio communication system according to the second embodiment is the same as the hardware configuration of the radio station 10A of FIG.
  • the reception antenna 51, the reception RF unit 52, the transmission RF unit 64, and the transmission antenna 65 of the radio station 50A are realized by, for example, an antenna and an RF circuit.
  • the signal generation unit 60, the reference signal generation unit 61, the physical channel multiplexing unit 62, and the IFFT unit 63 are realized by an integrated circuit such as a DSP or an integrated circuit such as a CPU.
  • the hardware configuration of the wireless terminal 70A in the wireless communication system according to the second embodiment is the same as the hardware configuration of the wireless terminal 20 of FIG.
  • the reception antenna 71, the reception RF unit 72, the transmission RF unit 84, and the transmission antenna 85 of the wireless terminal 70A are realized by, for example, an antenna and an RF circuit.
  • An FFT unit 73 An FFT unit 73, a physical channel separation unit 74, a signal demodulation unit 75, a channel estimation unit 76, a reception level measurement unit 77, a communication control unit 78, an upper layer data processing unit 79, and a signal of the radio terminal 70A
  • the generation unit 80, the reference signal generation unit 81, the physical channel multiplexing unit 82, and the IFFT unit 83 are realized by an integrated circuit such as a CPU, for example.
  • the radio stations 10A to 10C are provided as a communication mode so that CoMP communication is possible.
  • the radio stations 10A to 10C may use different communication methods.
  • the radio stations 10A to 10C may be radio stations capable of carrier aggregation.
  • the radio terminal UE # 2 exists in the cells C50A and B formed by the radio stations 50A and B.
  • connection establishment operation between the radio terminal UE and the radio stations eNB # 1 to 3 in the existing radio communication system will be described with reference to FIGS.
  • the arrangement of the radio terminal UE and the radio stations eNB1 # 1 to 3 is the same as the arrangement of the radio terminal UE # 2 and the radio stations 50A to 50C.
  • the radio stations eNB # 1-2 transmit signals of the broadcast channel BCH and the common control channel Common CCH (S21).
  • the signals of the broadcast channel BCH and the common control channel Common ⁇ ⁇ ⁇ CCH are also transmitted from the radio station eNB # 3, but cannot be received by the radio terminal UE and can receive signals from the radio stations eNB # 1-2. is there.
  • the reception level of the signal from the radio station eNB # 1 is higher than the reception level of the signal from the radio station eNB # 2.
  • the radio terminal UE acquires a radio resource element for transmitting the RACH to the radio station eNB # 1.
  • FIG. 12 illustrates RACH resources.
  • the horizontal axis represents frequency (f) and the vertical axis represents time (t).
  • subjected shows the example of the radio
  • the radio terminal UE exchanges signals with the radio station eNB # 1 to establish a connection (RRC Connected) (S23).
  • the radio terminal UE first establishes a connection with one radio station.
  • the radio terminal UE receives an RRC signal (RRC Signaling) from the radio station eNB # 1 (S24).
  • the radio terminal UE receives CSI-RSs from the radio stations eNB # 1-2 using the control information based on the RRC signal (S25).
  • the radio terminal UE transmits a response (CSI Feedback) to the CSI-RS.
  • the radio terminal UE transmits the reception level measured by the CSI-RS to the radio station eNB # 1 to execute the process of cooperative cooperation, or requests the cooperation cooperation based on the measured reception level. It transmits to radio station eNB # 1 (S26).
  • FIG. 13 is a sequence diagram of a connection establishment operation between the radio terminal UE # 2 and the radio stations 50A to 50C in the radio communication system 1A.
  • the radio station 50A sets virtual cell configuration information (Virtual Cell Information Set) and notifies the radio stations 50B to 50C (S41).
  • the virtual cell configuration information includes, for example, identification information for identifying the virtual cell, determination conditions for determining whether or not the wireless terminal requests connection to the virtual cell, and connection requests for connection to the virtual cell. Including arrangement of radio resource elements to be performed.
  • FIG. 14 illustrates the configuration information of the virtual cell. In the example of FIG. 14, virtual cells VC # A-B are set.
  • FIG. 15 illustrates a RACH resource.
  • the horizontal axis represents frequency (f) and the vertical axis represents time (t).
  • the hatched part is set as the RACH resource (a) for VC # A, and the hatched part is set as the RACH resource (b) for VC # B. Is done.
  • the radio stations 50A to 50B transmit the configuration information of the virtual cells VC # A and B (S42).
  • the virtual cells VC # A and B are broadcast from the radio stations 50A to 50B as BCH or Common CCH, respectively.
  • the radio terminal UE # 2 synchronizes with the radio stations 50A to 50B, and acquires the configuration information of the virtual cells VC # A and B from the BCH or Common CCH received from the radio stations 50A to 50B (S43). ).
  • the radio terminal UE # 2 receives the synchronization channel SCH transmitted from the radio stations 50A to 50B and synchronizes with the radio stations 50A to 50B.
  • the radio terminal UE # 2 determines connection with the virtual cell VC # A. Specifically, the radio terminal UE # 2 receives signals from the radio stations 50A to 50B forming the virtual cell VC # A and measures the reception level. Then, whether to make a connection request to the virtual cell VC # A is determined based on the measured reception level and the determination condition.
  • FIG. 16 illustrates the virtual cell VC # A.
  • FIG. 17 shows an example of determination conditions for the virtual cell VC # A. In FIG. 17, the vertical axis indicates the reception level (p), and the horizontal direction indicates radio terminals UE # 1, UE # 2, UE # 3 in order from the left.
  • the left hatched portion indicates the reception level from the radio station 50A
  • the right dotted portion indicates the reception level from the radio station 50B.
  • connection to the cell C50A is determined. Is done. Further, for example, when the determination condition for requesting connection to the cell C50B is not satisfied and the determination condition for requesting connection to the cell C50B is not satisfied, as in the case of the radio terminal UE # 3, the connection to the cell C50B is determined. Is done.
  • the radio terminal UE # 2 transmits a connection request (Virtual Cell Connection Request) with the virtual cell VC # A (S44).
  • the connection request with the virtual cell VC # A is transmitted using the radio resource element a set in the configuration information of the virtual cell VC # A.
  • a part of the radio resource elements prepared for establishing a connection to the cells C50A and B is allocated to the virtual cell VC # A.
  • the radio station 50A that has received the connection request grasps that it is a connection request to the virtual cell VC # A. can do.
  • preparation for connection with the virtual cell VC # A is executed without shifting to the establishment of connection to the cell C50A, and the shift to communication by cooperative cooperation is performed.
  • the radio stations 50A to 50B receive the connection request with the virtual cell VC # A and prepare the connection between the radio terminal UE # 2 and the virtual cell VC # A (Virtual Cell Connection Setup) (S45). Specifically, for example, the radio station 50A receives the connection request, and notifies the radio station 50B of information for establishing a connection with the radio terminal UE # 2.
  • connection establishment (RRC Connected) is executed between the radio terminal UE # 2 and the radio stations 50A and 50B (S46).
  • connection establishment RRC Connected
  • the cooperative cooperation is performed after the wireless terminal UE # 2 establishes the initial connection with the single wireless station 50A, for example.
  • communication by cooperative cooperation can be quickly started. That is, switching to cooperative cooperation is performed efficiently.
  • the radio communication system 1A it is possible to efficiently switch the communication mode between the radio terminals UE # 1 to UE # 3 and the radio stations 50A to 50C and improve the communication performance.
  • the wireless communication system 1 may be a heterogeneous network in which wireless stations having different cell ranges are mixed.
  • one of the radio stations 10A to 10B forms a PCell (Primary cell), and the other of the radio stations 10A to 10B forms an SCell (Secondary cell).
  • the SCell is a cell whose function may be more limited than that of the PCell. SCell corresponds to a relatively large cell (Macro Cell), and Pcell corresponds to a relatively small cell (Small Cell).
  • PCell is a serving cell (connected cell) of PCC (PrimaryPrimcomponent carrier)
  • SCell is a serving cell (connected cell) of SCC (Secondary component carrier).
  • PCC is switched by handover, while SCC is added or deleted as necessary.
  • the overall configuration of the wireless communication system according to the third embodiment is the same as that of the wireless communication system 1A shown in FIG.
  • each of the wireless stations 50A to 50C is connected to the network device 3 via a wired connection or a wireless connection
  • the network device 3 is connected to the network 2 via a wired connection or a wireless connection.
  • the radio stations 50A to 50C are provided so as to be able to transmit and receive data and control information via the network device 3 and the network 2.
  • each of the radio stations 50A to 50C has an antenna and corresponds to a communication point.
  • Radio stations 50A-C form cells C50A-C, respectively.
  • the radio stations 50A to 50C communicate with each other via a wired connection or a wireless connection.
  • the radio stations 50A to 50C can perform CoMP communication with the radio terminals UE # 1 to UE # 3.
  • the radio terminal UE # 1 exists in the cell C50A formed by the radio station 50A
  • the radio terminal UE # 2 exists in the cells C50A and B formed by the radio stations 50A and B
  • the radio terminal UE # 3. Exists in the cell C50B formed by the radio station 50B.
  • the functional configuration and hardware configuration of the radio stations 50A to 50C according to the third embodiment are the same as those of the radio station 50A of FIG. 9 of the second embodiment. Also, the functional configurations and hardware configurations of the radio terminals UE # 1 to UE # 3 according to the third embodiment are the same as those of the radio terminal 70A of FIG. 10 of the second embodiment.
  • FIG. 18 is a sequence diagram for explaining an operation of establishing a connection in the wireless communication system according to the third embodiment.
  • the connection establishment operation shown in the second embodiment is applied to the handover processing procedure.
  • the wireless stations 10A to 10C are provided so as to be capable of CoMP communication.
  • the radio stations 10A to 10C may use different communication methods.
  • the radio stations 10A to 10C may be radio stations capable of carrier aggregation.
  • the radio terminal UE # 2 exists in the cells C50A and B formed by the radio stations 50A and B.
  • connection establishment (RRCRRConnected) between the radio terminal UE # 2 and the radio station 50A is executed (S61), and the radio terminal UE # 2 is connected to the radio station 50A. It is in.
  • the radio station 50A sets the virtual cell configuration information (Virtual Cell Information Set) with the radio station 50B (S62). For example, the radio station 50A sets the virtual cell configuration information and notifies the radio stations 50B to 50C.
  • the configuration information of the virtual cell includes, for example, identification information for identifying the virtual cell, determination conditions for determining whether or not the radio terminals UE # 1 to UE # 3 request connection to the virtual cell, and connection to the virtual cell Including an arrangement of radio resource elements that transmit and receive a connection request.
  • the radio stations 50A to 50B transmit BCH and Common CCH (S63).
  • the radio terminal UE # 2 acquires control information from the BCH or Common CCH signal received by the connected radio station 50A.
  • the control information to be acquired includes information for receiving a reference signal from the radio station 50A, information for receiving a reference signal from the peripheral radio station 50B, and a handover determination condition for determining whether or not to execute a handover. (For example, Cell reselection parameters) and the like.
  • the radio terminal UE # 2 can also acquire control information from a signal received from the radio station 50B by synchronizing with the radio station 50B.
  • the radio terminal UE # 2 receives the reference signal RS transmitted from the radio stations 50A to 50B (S64).
  • the radio terminal UE # 2 starts a handover procedure (Handover Setup) (S65). For example, the radio terminal UE # 2 determines whether or not to execute the handover based on the measured reception level and the handover determination condition. In S65, for example, it is assumed that the reception levels of the radio stations 50A to 50B satisfy a handover determination condition for executing a handover from the radio station 50A to the radio station 50B.
  • the radio terminal UE # 2 acquires the configuration information of the virtual cells VC # A and B from the BCH or Common CCH signal received by the connected radio station 50A (S66). And radio
  • the virtual cell VC # It is determined that A is requested to connect.
  • the virtual cell VC # A it is determined that A is requested to connect.
  • the radio terminal UE # 2 transmits a connection request (Virtual Cell Connection Request) with the virtual cell VC # A (S67).
  • the connection request with the virtual cell VC # A is transmitted using the radio resource element a set in the configuration information of the virtual cell VC # A.
  • a part of the radio resource elements prepared for establishing a connection to the cells C50A and B is allocated to the virtual cell VC # A.
  • the radio station 50A that has received the connection request grasps that it is a connection request to the virtual cell VC # A. can do.
  • preparation for connection with the virtual cell VC # A is executed without shifting to establishment of connection to the cell C50B, and shift to communication by cooperative cooperation.
  • the radio stations 50A to 50B receive a connection request with the virtual cell VC # A, and prepare a connection (Virtual ⁇ Cell Connection Setup) between the radio terminal UE # 2 and the virtual cell VC # A (S68). Specifically, for example, the radio station 50A receives the connection request and notifies the radio station 50B of information for establishing a connection with the radio terminal UE # 2.
  • the communication mode between the wireless terminals 70A to 70C and the wireless stations 50A to 50C can be efficiently switched to improve the communication performance.
  • the wireless communication system of the first to third embodiments can be realized as an LTE-A system, for example. Note that the present invention can also be applied to a wireless communication system using a communication method other than LTE-A.
  • the wireless terminal is also referred to as a mobile station or a user apparatus (User Equipment, mentUE). Further, in the first to third embodiments, the wireless terminal can be applied to a mobile terminal such as a mobile phone, a smartphone, or a PDA (Personal Digital Assistant). In addition, the first to third embodiments can be applied to various communication devices that perform communication with a radio station such as a mobile relay station.
  • a mobile station such as a mobile phone, a smartphone, or a PDA (Personal Digital Assistant).
  • PDA Personal Digital Assistant
  • the first to third embodiments can be applied to various communication devices that perform communication with a radio station such as a mobile relay station.
  • the radio station is also referred to as a base station, a radio base station, or an access point.
  • the radio station can be applied to base stations of various scales such as a macro base station, a pico base station, and a femto base station.
  • the first to third embodiments can be applied to various communication devices that perform communication with a wireless terminal such as a relay station.
  • the wireless communication system can be realized with a wireless station as a base station.
  • the radio station can be realized as an independent eNodeB (evolved Node B).
  • the radio communication system may be realized by using some radio stations as base station control units and other radio stations as base station remote units.
  • the control unit can be realized as, for example, a centralized eNodeB and the remote unit can be realized as, for example, an RRH (Remote Radio Head) included in the centralized eNodeB.
  • the control unit is connected to the remote unit via a wired connection such as an optical cable.
  • the control unit forms a cell, and each remote unit forms a cover area that overlaps the cell. A virtual cell is set by regarding this cover area as one cell.
  • each component of the radio station and radio terminal is not limited to the mode of the first to third embodiments, and all or a part thereof can be used for various loads, usage conditions, etc. Accordingly, it may be configured to be functionally or physically distributed / integrated in an arbitrary unit.
  • the memory may be connected via a network or a cable as an external device of a wireless station or a wireless terminal.

Abstract

The objective of the technique disclosed herein is to provide a radio communication method, a radio communication system, a radio station and a radio terminal wherein communication states can be efficiently switched to improve the communication performance. A radio communication method comprises: transmitting, from a radio terminal, a connection request for connecting to a virtual cell obtained by integrating a plurality of cells; receiving the connection request at one or more of the plurality of radio stations forming the virtual cell; and executing establishment of the connection between the radio terminal and the plurality of radio stations forming the virtual cell.

Description

無線通信方法、無線通信システム、無線局および無線端末Wireless communication method, wireless communication system, wireless station, and wireless terminal
　本発明は、無線通信方法、無線通信システム、無線局および無線端末に関する。 The present invention relates to a wireless communication method, a wireless communication system, a wireless station, and a wireless terminal.
　近年、携帯電話システム等の無線通信システムにおいて、無線通信の更なる高速化・大容量化等を図るため、次世代の無線通信技術について議論が行われている。例えば、標準化団体である３ＧＰＰ（3rd Generation Partnership Project）では、ＬＴＥ（Long Term Evolution）と呼ばれる通信規格や、ＬＴＥの無線通信技術をベースとしたＬＴＥ－Ａ（LTE - Advanced）と呼ばれる通信規格が提案されている。 In recent years, next-generation wireless communication technologies have been discussed in order to further increase the speed and capacity of wireless communication in wireless communication systems such as mobile phone systems. For example, 3GPP (3rd Generation Partnership Project), a standardization organization, proposes a communication standard called LTE (Long Term Evolution) and a communication standard called LTE-A (LTE-Advanced) based on LTE wireless communication technology. Has been.
　ＬＴＥ－Ａシステム等において、異種の通信ネットワークを混合して構築されるヘテロジニアスネットワーク（Heterogeneous Network, HetNet）や、複数の無線周波数キャリアを連結するキャリアアグリゲーション（Carrier Aggregation, CA）や、複数の通信ポイントが協調して通信を行う多地点協調（Coordinated MultiPoint, CoMP）通信等の技術により、例えば所定の無線端末に対する無線通信リソースの割当てを増やしてスループット向上を図り、通信性能を向上させる方法が検討されている。 In LTE-A systems, etc., heterogeneous networks (Heterogeneous Network, HetNet) constructed by mixing different types of communication networks, carrier aggregation (Carrier Aggregation, CA) linking multiple radio frequency carriers, and multiple communications A method for improving communication performance by increasing the allocation of wireless communication resources to a given wireless terminal, for example, by using technologies such as multi-point coordinated (Coordinated MultiPoint, CoMP) communication in which points perform communication in cooperation is studied. Has been.
　しかしながら、通信性能の向上を実現するためには、制御の遅延やシグナリングの増大の考慮のもとで、スループットの向上となるよう、様々の通信態様を適切に調整する必要がある。このとき、例えばネットワーク構成や通信状況によって、通信態様は無線端末毎に多様に変わり得ることが想定される。例えば、ＣｏＭＰ通信可能な通信ポイントは多数存在する可能性があり、ＣｏＭＰ通信で実際に信号の送信に使用する通信ポイントの数や組み合わせは多様となる。さらに例えば、異種の通信ネットワークの数や組み合わせ、連結可能な無線周波数キャリアの数や組み合わせも、多様となることが想定される。このような状況では、この多様に変わり得る通信態様に対応するよう、例えば参照信号や制御情報を所定の手順でやり取りし、適切な通信態様を選択して切り替える必要がある。このとき、通信態様の切り替えが効率良く行われないと、通信性能の向上を妨げる恐れがある。 However, in order to improve the communication performance, it is necessary to appropriately adjust various communication modes so as to improve the throughput in consideration of a control delay and an increase in signaling. At this time, for example, it is assumed that the communication mode can be variously changed for each wireless terminal depending on the network configuration and the communication status. For example, there may be many communication points capable of CoMP communication, and the number and combination of communication points actually used for signal transmission in CoMP communication vary. Furthermore, for example, the number and combination of different types of communication networks and the number and combination of connectable radio frequency carriers are expected to vary. In such a situation, it is necessary to exchange, for example, a reference signal and control information according to a predetermined procedure, and to select and switch an appropriate communication mode so as to correspond to the communication mode that can be variously changed. At this time, if the communication mode is not switched efficiently, the communication performance may be prevented from improving.
　開示の技術は、上記に鑑みてなされたものであって、通信態様を効率良く切り替えて、通信性能を向上できる無線通信方法、無線通信システム、無線局および無線端末を提供することを目的とする。 The disclosed technology has been made in view of the above, and an object thereof is to provide a wireless communication method, a wireless communication system, a wireless station, and a wireless terminal that can efficiently switch communication modes and improve communication performance. .
　上述した課題を解決し、目的を達成するために、本件の開示する無線通信方法は、無線端末から、複数のセルを１つにまとめた仮想セルに接続するための接続要求を送信し、前記仮想セルを形成する複数の無線局のうちの少なくとも１つの無線局で、前記接続要求を受信し、前記無線端末と前記仮想セルを形成する複数の無線局との接続確立を実行する。 In order to solve the above-described problems and achieve the object, the wireless communication method disclosed in the present application transmits a connection request for connecting to a virtual cell in which a plurality of cells are combined into one, from the wireless terminal, At least one of the plurality of wireless stations forming the virtual cell receives the connection request and establishes connection between the wireless terminal and the plurality of wireless stations forming the virtual cell.
　本件の開示する無線通信方法の一つの態様によれば、通信態様を効率良く切り替えて、通信性能を向上できるという効果を奏する。 According to one aspect of the wireless communication method disclosed in this case, there is an effect that the communication aspect can be efficiently switched to improve the communication performance.
図１は、第１実施形態に係る無線通信システムの構成を示す図である。FIG. 1 is a diagram illustrating a configuration of a wireless communication system according to the first embodiment. 図２は、第１実施形態に係る無線局の構成を示すブロック図である。FIG. 2 is a block diagram showing the configuration of the radio station according to the first embodiment. 図３は、第１実施形態に係る無線端末の構成を示すブロック図である。FIG. 3 is a block diagram showing the configuration of the wireless terminal according to the first embodiment. 図４は、第１実施形態に係る無線局のハードウェア構成を示す図である。FIG. 4 is a diagram illustrating a hardware configuration of the radio station according to the first embodiment. 図５は、第１実施形態に係る無線端末のハードウェア構成を示す図である。FIG. 5 is a diagram illustrating a hardware configuration of the wireless terminal according to the first embodiment. 図６は、第１実施形態に係る無線通信システムの動作を説明するためのシーケンス図である。FIG. 6 is a sequence diagram for explaining the operation of the wireless communication system according to the first embodiment. 図７は、第１実施形態に係る無線通信システムの動作例を説明するための図である。FIG. 7 is a diagram for explaining an operation example of the wireless communication system according to the first embodiment. 図８は、第２実施形態に係る無線通信システムの構成を示す図である。FIG. 8 is a diagram illustrating a configuration of a wireless communication system according to the second embodiment. 図９は、第２実施形態に係る無線局の構成を示すブロック図である。FIG. 9 is a block diagram showing a configuration of a radio station according to the second embodiment. 図１０は、第２実施形態に係る無線端末の構成を示すブロック図である。FIG. 10 is a block diagram illustrating a configuration of a wireless terminal according to the second embodiment. 図１１は、第２実施形態に係る無線通信システムの動作に関する説明を示す図である。FIG. 11 is a diagram illustrating an operation related to the operation of the wireless communication system according to the second embodiment. 図１２は、図１１の説明に関するＲＡＣＨリソース例を示す図である。FIG. 12 is a diagram illustrating an example of a RACH resource related to the description of FIG. 図１３は、第２実施形態に係る無線通信システムの動作を説明するためのシーケンス図である。FIG. 13 is a sequence diagram for explaining the operation of the radio communication system according to the second embodiment. 図１４は、第２実施形態に係る無線通信システムの仮想セルの構成情報の例を説明するための図である。FIG. 14 is a diagram for explaining an example of the configuration information of the virtual cell of the wireless communication system according to the second embodiment. 図１５は、図１４の説明に関するＲＡＣＨリソースの例を示す図である。FIG. 15 is a diagram illustrating an example of a RACH resource related to the description of FIG. 図１６は、第２実施形態に係る無線通信システムの動作例を説明するための図である。FIG. 16 is a diagram for explaining an operation example of the wireless communication system according to the second embodiment. 図１７は、第２実施形態に係る無線通信システムにおける接続確立の判定条件を説明するための図である。FIG. 17 is a diagram for explaining determination conditions for establishing a connection in the wireless communication system according to the second embodiment. 図１８は、第３実施形態に係る無線通信システムの動作を説明するためのシーケンス図である。FIG. 18 is a sequence diagram for explaining the operation of the wireless communication system according to the third embodiment.
　以下に、本件の開示する無線通信方法、無線通信システム、無線局および無線端末の実施例を、図面を参照しながら説明する。なお、以下の実施例により本件の開示する無線通信方法、無線通信システム、無線局および無線端末が限定されるものではない。 Hereinafter, embodiments of a wireless communication method, a wireless communication system, a wireless station, and a wireless terminal disclosed in the present application will be described with reference to the drawings. The wireless communication method, the wireless communication system, the wireless station, and the wireless terminal disclosed in the present application are not limited to the following embodiments.
［第１実施形態］
　図１は、第１実施形態に係る無線通信システム１の構成を示す。図１に示すように、無線通信システム１は、無線局１０Ａ～Ｂと、無線端末２０とを有する。無線局１０Ａ～Ｂはそれぞれ、アンテナを有し、通信ポイントに相当する。通信ポイントは、例えば、無線アクセスポイント、基地局、通信ユニット、アンテナ或いはこれらにより形成されるセルに相当する。無線局１０ＡはセルＣ１０Ａを形成し、無線局１０ＢはセルＣ１０Ｂを形成している。 [First Embodiment]
FIG. 1 shows a configuration of a wireless communication system 1 according to the first embodiment. As shown in FIG. 1, the radio communication system 1 includes radio stations 10A to 10B and a radio terminal 20. Each of the radio stations 10A to 10B has an antenna and corresponds to a communication point. The communication point corresponds to, for example, a wireless access point, a base station, a communication unit, an antenna, or a cell formed by these. The radio station 10A forms a cell C10A, and the radio station 10B forms a cell C10B.
　無線局１０Ａ～Ｂは、無線局１０Ａ～Ｂ間で有線接続あるいは無線接続を介して通信を行う。また、無線局１０Ａ～Ｂは、無線端末２０に対してＣｏＭＰ通信が可能である。例えば、無線端末２０との下りリンクのＣｏＭＰ通信では、無線局１０Ａ～Ｂのうち下りリンクのＣｏＭＰ通信で使用するセットとして選択される１以上の通信ポイントから、無線端末２０に、同じ時間・周波数の無線リソースを用いてデータを送信する結合送信が行われる。また、例えば、無線端末２０との上りリンクのＣｏＭＰ通信では、無線局１０Ａ～Ｂのうち上りリンクのＣｏＭＰ通信で使用するセットとして選択される１以上の通信ポイントで、無線端末２０からのデータをそれぞれ受信し、受信信号を通信ポイント間で合成する結合受信が行われる。 The wireless stations 10A to 10B communicate with each other through a wired connection or a wireless connection. Further, the radio stations 10A to 10B can perform CoMP communication with the radio terminal 20. For example, in downlink CoMP communication with the radio terminal 20, one or more communication points selected as a set to be used in downlink CoMP communication among the radio stations 10A to 10B are transmitted to the radio terminal 20 from the same time and frequency. The combined transmission is performed to transmit data using the wireless resources. Further, for example, in uplink CoMP communication with the radio terminal 20, data from the radio terminal 20 is transmitted at one or more communication points selected as a set to be used for uplink CoMP communication among the radio stations 10A to 10B. Each reception is performed, and the combined reception is performed in which the received signals are combined between the communication points.
　また、例えば、無線局１０Ａ～Ｂはそれぞれ、有線接続あるいは無線接続を介してネットワーク装置３と接続され、ネットワーク装置３は有線接続あるいは無線接続を介してネットワーク２に接続される。そして、無線局１０Ａ～Ｂは、ネットワーク装置３及びネットワーク２を介して、データや制御情報を送受信可能に設けられている。 Further, for example, the radio stations 10A to 10B are each connected to the network device 3 via a wired connection or a wireless connection, and the network device 3 is connected to the network 2 via a wired connection or a wireless connection. The radio stations 10A to 10B are provided so as to be able to transmit and receive data and control information via the network device 3 and the network 2.
　図２は、無線局１０Ａの機能的構成を示すブロック図である。図２に示すように、無線局１０Ａは、受信部１１と、送信部１２と、制御部１３とを備える。これら各構成部分は、一方向または双方向に、信号やデータの入出力が可能なように接続されている。なお、無線局１０Ｂの機能的構成およびハードウェア構成は、無線局１０Ａの機能的構成及びハードウェア構成と同様である。以下の説明では、無線端末２０は無線局１０Ａが形成するセルＣ１０Ａに存在し、通信開始の際に、無線局１０Ａとの同期を行うものとする。 FIG. 2 is a block diagram showing a functional configuration of the radio station 10A. As illustrated in FIG. 2, the radio station 10A includes a reception unit 11, a transmission unit 12, and a control unit 13. Each of these components is connected so that signals and data can be input and output in one direction or in both directions. Note that the functional configuration and hardware configuration of the radio station 10B are the same as the functional configuration and hardware configuration of the radio station 10A. In the following description, it is assumed that the wireless terminal 20 exists in the cell C10A formed by the wireless station 10A and synchronizes with the wireless station 10A when communication is started.
　受信部１１は、データ信号や制御信号を、アンテナを介して受信する。受信部１１は、例えば上りのデータチャネルや制御チャネル上を伝送される上り信号を受信する。上りのデータチャネルとしては例えば、個別データチャネルが挙げられる。また、上りの制御チャネルとしては例えば、ランダムアクセスチャネルや、個別制御チャネルが挙げられる。受信する信号としては例えば、無線端末２０からの接続確立のための接続要求や、無線端末２０での通信レベルを示す信号や、チャネル推定や復調のために用いられる参照信号（パイロット信号とも称される）が挙げられる。接続要求としては例えば、セルＣ１０Ａに接続するための接続要求や、後述の仮想セルに接続するための接続要求が挙げられる。 The receiving unit 11 receives a data signal and a control signal via an antenna. For example, the reception unit 11 receives an uplink signal transmitted on an uplink data channel or a control channel. An example of the uplink data channel is an individual data channel. Further, examples of the uplink control channel include a random access channel and a dedicated control channel. As a signal to be received, for example, a connection request for establishing a connection from the radio terminal 20, a signal indicating a communication level at the radio terminal 20, a reference signal used for channel estimation or demodulation (also referred to as a pilot signal). ). Examples of the connection request include a connection request for connecting to the cell C10A and a connection request for connecting to a virtual cell described later.
　送信部１２は、データ信号や制御信号を、アンテナを介して送信する。なお、アンテナは送信と受信で共通でも、別体でもよい。送信部１２は、例えば下りのデータチャネルや制御チャネル上を伝送される下り信号を送信する。下りのデータチャネルとしては例えば、共通データチャネルや、個別データチャネルが挙げられる。また、下りの制御チャネルとしては例えば、同期チャネルや、報知チャネルや、共通制御チャネルや、個別制御チャネルが挙げられる。送信する信号としては例えば、システム情報やセル共通の制御情報を報知する信号や、接続中の無線端末２０に個別制御チャネル上で伝送される制御信号や、接続中の無線端末２０に個別データチャネル上で伝送される制御信号や、接続中の無線端末２０に個別データチャネル上で伝送されるデータ信号が挙げられる。また、送信する信号としては例えば、無線端末２０へ呼の着信があった場合に無線端末２０を呼び出すためのページング信号や、無線端末２０からの上り送信電力の制御のための制御信号が挙げられる。また、送信する信号としては例えば、セル固有の参照信号（共通パイロット信号とも称される）や、チャネル推定や復調のために用いられる無線端末個別の参照信号（個別パイロット信号とも称される）や、これらの参照信号の送信に準備される無線リソースを示す構成情報が挙げられる。また、送信する信号は、無線局１０Ａ～Ｂでの通信レベルを示す信号や、無線端末２０からの接続確立のための信号への応答信号を含む。また、送信する信号は、セルＣ１０Ａの構成情報（セルＣ１０Ａに接続するための接続情報）や、セルＣ１０Ａの周辺セルＣ１０Ｂの構成情報（セルＣ１０Ｂに接続するための接続情報）を含む。これらの構成情報は、例えばシステム情報やセル共通の制御情報として報知されてもよい。セルＣ１０Ａに接続するための接続情報は例えば、セルＣ１０Ａを識別するための識別情報を含む。セルＣ１０Ｂに接続するための接続情報は例えば、セルＣ１０Ｂを識別するための識別情報を含む。 The transmission unit 12 transmits a data signal and a control signal via an antenna. The antenna may be common for transmission and reception or may be separate. The transmission unit 12 transmits, for example, a downlink signal transmitted on a downlink data channel or control channel. Examples of the downlink data channel include a common data channel and a dedicated data channel. Further, examples of the downlink control channel include a synchronization channel, a broadcast channel, a common control channel, and an individual control channel. As a signal to be transmitted, for example, a signal for informing system information or control information common to cells, a control signal transmitted to the connected wireless terminal 20 on the dedicated control channel, or a dedicated data channel to the connected wireless terminal 20 The control signal transmitted above and the data signal transmitted on the dedicated data channel to the connected wireless terminal 20 can be mentioned. Examples of the signal to be transmitted include a paging signal for calling the wireless terminal 20 when a call arrives at the wireless terminal 20 and a control signal for controlling the uplink transmission power from the wireless terminal 20. . Further, as a signal to be transmitted, for example, a cell-specific reference signal (also referred to as a common pilot signal), a wireless terminal-specific reference signal (also referred to as an individual pilot signal) used for channel estimation or demodulation, Configuration information indicating radio resources prepared for transmission of these reference signals is included. The signal to be transmitted includes a signal indicating the communication level at the radio stations 10A to 10B and a response signal to the signal for establishing a connection from the radio terminal 20. The signal to be transmitted includes configuration information of cell C10A (connection information for connection to cell C10A) and configuration information of peripheral cell C10B of cell C10A (connection information for connection to cell C10B). Such configuration information may be broadcast as, for example, system information or control information common to cells. The connection information for connecting to the cell C10A includes, for example, identification information for identifying the cell C10A. The connection information for connecting to the cell C10B includes, for example, identification information for identifying the cell C10B.
　また、送信する信号は、仮想セルの構成情報（仮想セルに接続するための接続情報）を含む。仮想セルは例えば、複数のセルを１つにまとめたセルである。仮想セルは例えば、マルチセルあるいはグループセル等と称してもよい。あるいは仮想セルは例えば、各無線局に対応する物理セルに対して、論理セルと称してもよい。仮想セルは例えば、複数のセルの各セルの少なくとも一部をカバーするように形成される。 Also, the signal to be transmitted includes virtual cell configuration information (connection information for connecting to the virtual cell). For example, the virtual cell is a cell in which a plurality of cells are combined into one. The virtual cell may be referred to as a multi-cell or a group cell, for example. Or a virtual cell may be called a logical cell with respect to the physical cell corresponding to each radio station, for example. For example, the virtual cell is formed so as to cover at least a part of each of the plurality of cells.
　仮想セルの構成情報は、例えばシステム情報やセル共通の制御情報として報知されてもよい。また例えば、仮想セルの構成情報は、システム情報やセル共通の制御情報のフォーマットの、予め準備された領域に格納して送信するようにしてもよいし、拡張領域等に所定の制御タイミングや所定の期間に応じて格納して送信するようにしてもよい。 The virtual cell configuration information may be broadcasted as system information or common cell control information, for example. Further, for example, the configuration information of the virtual cell may be stored and transmitted in an area prepared in advance in the format of the system information or the control information common to the cells, or may be transmitted in a predetermined control timing or in a predetermined area. The data may be stored and transmitted according to the period.
　仮想セルに接続するための接続情報は例えば、仮想セルを識別するための識別情報を含む。仮想セルを識別するための識別情報は例えば、仮想セルに含まれる複数のセルをそれぞれ識別するための複数のセル識別情報を含む。また、仮想セルに接続するための接続情報は例えば、仮想セルに接続するための接続要求を送信するための無線リソースの割当てや、仮想セルに接続するための接続要求の構成情報や、仮想セルへ接続するか否かを判定するための判定条件を含んでもよい。無線リソースの割当ては例えば、接続要求に使用されるリソースエレメント（時間周波数リソースとも称する）の配置を示す。 The connection information for connecting to the virtual cell includes, for example, identification information for identifying the virtual cell. The identification information for identifying the virtual cell includes, for example, a plurality of cell identification information for identifying each of the plurality of cells included in the virtual cell. The connection information for connecting to the virtual cell includes, for example, radio resource allocation for transmitting a connection request for connecting to the virtual cell, connection request configuration information for connecting to the virtual cell, virtual cell A determination condition for determining whether or not to connect to may be included. The allocation of radio resources indicates, for example, the arrangement of resource elements (also referred to as time frequency resources) used for connection requests.
　仮想セルに接続するための接続要求は例えば、無線端末２０から、初期接続時のランダムアクセス、再接続時のランダムアクセス、およびハンドオーバ時のランダムアクセスの少なくともいずれかとして送信される。仮想セルに接続するための接続要求を送信するための無線リソースとしては例えば、ランダムアクセスに準備される無線リソースを用いることができる。このとき例えば、通常のランダムアクセスに準備される無線リソースの一部を、所定の制御タイミングや所定の期間に応じて、仮想セルに接続するための接続要求を送信するための無線リソースに割当ててもよい。または例えば、仮想セルに接続するための接続要求を送信するための無線リソースを通常のランダムアクセスに準備される無線リソースとは別に、予め準備してもよい。 The connection request for connecting to the virtual cell is transmitted from the wireless terminal 20 as at least one of random access at the time of initial connection, random access at the time of reconnection, and random access at the time of handover. As a radio resource for transmitting a connection request for connecting to a virtual cell, for example, a radio resource prepared for random access can be used. At this time, for example, a part of radio resources prepared for normal random access is allocated to radio resources for transmitting a connection request for connecting to a virtual cell according to a predetermined control timing or a predetermined period. Also good. Or for example, you may prepare beforehand the radio | wireless resource for transmitting the connection request | requirement for connecting to a virtual cell separately from the radio | wireless resource prepared for normal random access.
　制御部１３は、有線接続あるいは無線接続を介して、ネットワーク装置３や他の無線局１０Ｂとデータや制御情報の送受信を行う。制御部１３は、受信されるデータや制御情報を受信部１１から入力する。また、制御部１３は、送信するデータや制御情報を送信部１２に出力する。また、制御部１３は、通信インタフェースを介して有線ネットワーク経由でデータや制御情報の送受信を行う。また、制御部１３は、無線端末２０とのアクセスの管理や、無線端末２０への無線リソースの割当て等のスケジューリングを行う。 The control unit 13 transmits / receives data and control information to / from the network device 3 and other wireless stations 10B via a wired connection or a wireless connection. The control unit 13 inputs received data and control information from the reception unit 11. Further, the control unit 13 outputs data to be transmitted and control information to the transmission unit 12. In addition, the control unit 13 transmits and receives data and control information via a wired network via a communication interface. In addition, the control unit 13 performs management such as access management with the wireless terminal 20 and allocation of wireless resources to the wireless terminal 20.
　制御部１３は例えば、周辺無線局１０Ｂと情報をやり取りし、仮想セルの構成情報を設定する。制御部１３は例えば、セル配置や、各セルで使用される無線通信方式や、各セルで使用される無線周波数キャリア等に基づいて、取り得る１又は複数の仮想セルの構成情報を設定する。また、制御部１３は例えば、無線局１０Ａが接続中の無線端末の数、無線局１０Ａと接続中の無線端末との間の通信レベル、他の無線局１０Ｂが接続中の無線端末の数、他の無線局１０Ｂと接続中の無線端末との間の通信レベル、無線局１０Ａからデータを送信する通信モード、他の無線局１０Ｂからデータを送信する通信モード、の少なくともいずれかを考慮して、仮想セルの構成情報を設定してもよい。無線局１０Ａ～Ｂと無線端末２０との間の通信レベルは例えば、上り参照信号あるいは下り参照信号から測定される。通信レベルは例えば、無線端末２０から報告されてもよく、無線局１０Ａと無線端末２０との間の通信レベルを無線局１０Ａで測定するともに、無線局１０Ｂと無線端末２０との間の通信レベルを無線局１０Ｂで測定して無線局１０Ａに通知してもよい。また、通信モードとしては例えば、シングルアンテナ通信、ＭＩＭＯ通信、およびＣｏＭＰ通信が挙げられる。ＭＩＭＯ通信は例えば、ＭＵ(Multi User)－ＭＩＭＯ通信およびＳＵ(Single User)－ＭＩＭＯ通信を含む。ＣｏＭＰ通信は例えば、後述のＤＰＳ（Dynamic Point Selection）－ＣＯＭＰ通信、ＪＴ（Joint transmission）－ＣｏＭＰ通信およびＪＲ（Joint reception）－ＣｏＭＰ通信を含む。ＤＰＳは、複数の通信ポイントのうち送信に使用する通信ポイントを動的に選択する方法である。また、ＪＴは、複数の通信ポイントから送信された信号を結合処理（合成処理）する方法である。また、ＪＲは、複数の通信ポイントのそれぞれで信号を受信し、通信ポイント間で結合処理（合成処理）する方法である。 For example, the control unit 13 exchanges information with the peripheral radio station 10B and sets the configuration information of the virtual cell. For example, the control unit 13 sets possible configuration information of one or a plurality of virtual cells based on the cell arrangement, the wireless communication scheme used in each cell, the radio frequency carrier used in each cell, and the like. In addition, the control unit 13 includes, for example, the number of wireless terminals connected to the wireless station 10A, the communication level between the wireless station 10A and the connected wireless terminal, the number of wireless terminals connected to the other wireless station 10B, Considering at least one of the communication level between the other wireless station 10B and the connected wireless terminal, the communication mode for transmitting data from the wireless station 10A, and the communication mode for transmitting data from the other wireless station 10B The configuration information of the virtual cell may be set. The communication level between the radio stations 10A to 10B and the radio terminal 20 is measured from, for example, an uplink reference signal or a downlink reference signal. For example, the communication level may be reported from the radio terminal 20, and the communication level between the radio station 10A and the radio terminal 20 is measured by the radio station 10A, and the communication level between the radio station 10B and the radio terminal 20 is measured. May be measured by the radio station 10B and notified to the radio station 10A. Examples of the communication mode include single antenna communication, MIMO communication, and CoMP communication. The MIMO communication includes, for example, MU (Multi-User) -MIMO communication and SU (Single-User) -MIMO communication. The CoMP communication includes, for example, DPS (Dynamic Point Selection) -COMP communication, JT (Joint Transmission) -CoMP communication, and JR (Joint reception) -CoMP communication described later. DPS is a method of dynamically selecting a communication point to be used for transmission among a plurality of communication points. JT is a method for combining (synthesizing) signals transmitted from a plurality of communication points. JR is a method of receiving a signal at each of a plurality of communication points and combining (combining) the communication points.
　仮想セルの構成情報は例えば、所定の制御タイミングで更新されてもよい。また例えば、仮想セルの構成情報は、予め格納されたあるいは設定された構成情報の候補から、所定の制御タイミングで選択されてもよい。 The virtual cell configuration information may be updated at a predetermined control timing, for example. Further, for example, the configuration information of the virtual cell may be selected at a predetermined control timing from candidates for configuration information stored or set in advance.
　仮想セルの構成情報は、無線局１０Ａと、自局周辺の他の無線局とで、共通に使用される。自局周辺の他の無線局は、ＣｏＭＰ通信可能な他の無線局１０Ｂを含む。 The virtual cell configuration information is commonly used by the radio station 10A and other radio stations around the own station. Other wireless stations around the own station include another wireless station 10B capable of CoMP communication.
　仮想セルの構成情報は例えば、無線局１０Ａで設定してもよく、無線局１０Ｂで設定してもよく、ネットワーク装置３やネットワーク２上の他の装置が無線局１０Ａ～Ｂと情報をやり取りして設定してもよい。また、仮想セルの構成情報は例えば、無線局１０Ａ～Ｂの一方の無線局から他方の無線局へ有線通信あるいは無線通信を介して通知されてもよく、ネットワーク装置３やネットワーク２上の他の装置から無線局１０Ａ～Ｂに通知してもよい。また、仮想セルの構成情報自体を通知する代わりに、予め格納されたあるいは設定された構成情報の候補から、所定の仮想セルの構成情報を選択するための情報を通知してもよい。また、仮想セルの構成情報は例えば、ネットワーク装置３やネットワーク２上の他の装置に格納され、所定の制御タイミングで無線局１０Ａ～Ｂからアクセスして取得するようにしてもよい。また、仮想セルの構成情報自体を通知する代わりに、格納された仮想セルの構成情報にアクセスするための情報を通知してもよい。 The virtual cell configuration information may be set by the radio station 10A or the radio station 10B, for example, and other devices on the network device 3 or the network 2 exchange information with the radio stations 10A to 10B. May be set. Also, the virtual cell configuration information may be notified from one of the radio stations 10A to 10B to the other radio station via wired communication or wireless communication. The apparatus may notify the radio stations 10A-B. Further, instead of notifying the virtual cell configuration information itself, information for selecting predetermined virtual cell configuration information from candidates of configuration information stored or set in advance may be notified. Further, the configuration information of the virtual cell may be stored in, for example, the network device 3 or another device on the network 2, and may be acquired by accessing from the radio stations 10A to 10B at a predetermined control timing. Further, instead of notifying the virtual cell configuration information itself, information for accessing the stored virtual cell configuration information may be notified.
　そして制御部１３は、無線端末２０から仮想セルに接続するための接続要求を受信すると、仮想セルとの無線端末２０との接続を準備する。詳細には例えば、制御部１３は、仮想セルを形成する他の無線局との間で制御情報をやり取りして、接続のためのパラメータを準備する。例えば制御部１３は、無線端末２０との接続確立のための情報を、仮想セルを形成する他の無線局に通知する。または、制御部１３は、無線端末２０との接続確立のための情報を所定の場所に格納し、格納した情報にアクセスするための情報を、仮想セルを形成する他の無線局に通知してもよい。 And the control part 13 will prepare the connection with the radio | wireless terminal 20 with a virtual cell, if the connection request for connecting to a virtual cell from the radio | wireless terminal 20 is received. Specifically, for example, the control unit 13 prepares parameters for connection by exchanging control information with other radio stations forming the virtual cell. For example, the control unit 13 notifies information for establishing a connection with the radio terminal 20 to other radio stations forming the virtual cell. Alternatively, the control unit 13 stores information for establishing a connection with the wireless terminal 20 in a predetermined location, and notifies other wireless stations that form the virtual cell of information for accessing the stored information. Also good.
　そして制御部１３は、無線端末との間で制御情報をやり取りして接続を確立する。同様に、仮想セルを形成する他の無線局も、無線端末２０との間で制御情報をやり取りして接続を確立する。 The control unit 13 establishes a connection by exchanging control information with the wireless terminal. Similarly, other wireless stations forming the virtual cell also exchange control information with the wireless terminal 20 to establish a connection.
　図３は、無線端末２０の構成を示す機能ブロック図である。図３に示すように、無線端末２０は、受信部２１と、送信部２２と、制御部２３とを備える。これら各構成部分は、一方向または双方向に、信号やデータの入出力が可能なように接続されている。 FIG. 3 is a functional block diagram showing the configuration of the wireless terminal 20. As illustrated in FIG. 3, the wireless terminal 20 includes a reception unit 21, a transmission unit 22, and a control unit 23. Each of these components is connected so that signals and data can be input and output in one direction or in both directions.
　受信部２１は、無線局１０Ａ～Ｂから送信されたデータ信号や制御信号を、アンテナを介して受信する。受信する信号としては例えば、システム情報やセル共通の制御情報を報知する信号や、接続無線局１０Ａから個別制御チャネル上で伝送される制御信号や、接続無線局１０Ａから個別データチャネル上で伝送される制御信号が挙げられる。また、受信する信号としては例えば、無線端末２０を呼び出すためのページング信号や、無線端末２０からの接続確立のための信号への応答信号や、無線局１０Ａ～Ｂでの通信レベルを示す信号や、上り送信電力の制御のための制御信号が挙げられる。また、受信する信号は例えば、セル固有の参照信号や、チャネル推定や復調のために用いられる無線端末個別の参照信号や、これらの参照信号の送信に準備される無線リソースを示す構成情報を含む。受信する信号は例えば、無線局１０Ａから送信される、セルＣ１０Ａの構成情報や周辺セルＣ１０Ｂの構成情報を含む。また、送信する信号は例えば、仮想セルの構成情報を含む。 The receiving unit 21 receives data signals and control signals transmitted from the radio stations 10A to 10B via the antenna. As a signal to be received, for example, a signal for reporting system information and control information common to cells, a control signal transmitted from the connection radio station 10A on the dedicated control channel, and a signal transmitted from the connection radio station 10A on the dedicated data channel Control signals. The received signal includes, for example, a paging signal for calling the wireless terminal 20, a response signal to a signal for establishing a connection from the wireless terminal 20, a signal indicating the communication level at the wireless stations 10A to 10B, And a control signal for controlling uplink transmission power. The received signal includes, for example, a cell-specific reference signal, a reference signal for each wireless terminal used for channel estimation and demodulation, and configuration information indicating a radio resource prepared for transmission of these reference signals. . The received signal includes, for example, the configuration information of the cell C10A and the configuration information of the neighboring cell C10B transmitted from the radio station 10A. Further, the signal to be transmitted includes, for example, virtual cell configuration information.
　送信部２２は、データ信号や制御信号を、アンテナを介して送信する。なお、アンテナは送信と受信で共通でも、別体でもよい。送信部２２は、例えば上りのデータチャネルや制御チャネル上を伝送される上り信号を送信する。送信する信号としては例えば、接続確立のための接続要求や、無線端末２０での通信レベルを示す信号や、チャネル推定や復調のために用いられる参照信号が挙げられる。接続要求としては例えば、セルＣ１０Ａに接続するための接続要求や、仮想セルに接続するための接続要求が挙げられる。 The transmission unit 22 transmits a data signal and a control signal via an antenna. The antenna may be common for transmission and reception or may be separate. The transmission unit 22 transmits, for example, an uplink signal transmitted on an uplink data channel or a control channel. Examples of the signal to be transmitted include a connection request for establishing a connection, a signal indicating a communication level at the wireless terminal 20, and a reference signal used for channel estimation and demodulation. Examples of the connection request include a connection request for connecting to the cell C10A and a connection request for connecting to the virtual cell.
　制御部２３は、受信されるデータや制御情報を受信部２１から入力する。また、送信するデータや制御情報を送信部２２に出力する。また、制御部２３は、無線局とのアクセスの管理や、送信信号の送信電力の制御等の通信制御を行う。また、通信制御は例えば、ＣｏＭＰ通信のための処理や、キャリアアグリゲーションのための処理や、ハンドオーバ（Inter-Cell, Inter-Frequency, Inter-Rat等）のための処理を含む。 The control unit 23 inputs received data and control information from the reception unit 21. In addition, data to be transmitted and control information are output to the transmission unit 22. In addition, the control unit 23 performs communication control such as management of access to a radio station and control of transmission power of a transmission signal. The communication control includes, for example, processing for CoMP communication, processing for carrier aggregation, and processing for handover (Inter-Cell, Inter-Frequency, Inter-Rat, etc.).
　また、制御部２３は、無線局１０Ａ～Ｂとの通信状態を示す情報を取得する。詳細には例えば、制御部２３は、無線局１０Ａ～Ｂから受信される信号を検知し、通信レベルを取得する。例えば制御部２３は、セル固有の参照信号や無線端末個別の参照信号を検知し、通信レベルを取得する。通信レベルは例えば、受信電力や受信品質を含む。通信レベルとして例えば、ＲＳＲＰ（Reference Signal Received Power）、ＲＳＲＱ（Reference Signal Received Quality）（＝受信電力値／総電力値）、ＳＩＲ（Signal to Interference Ratio）、ＳＩＮＲ（Signal to Interference and Noise Ratio）等が挙げられる。 Further, the control unit 23 acquires information indicating a communication state with the radio stations 10A to 10B. Specifically, for example, the control unit 23 detects signals received from the radio stations 10A to 10B, and acquires a communication level. For example, the control unit 23 detects a cell-specific reference signal or a wireless terminal-specific reference signal, and acquires a communication level. The communication level includes, for example, reception power and reception quality. As the communication level, for example, RSRP (Reference Signal Received Power), RSRQ (Reference Signal Received Quality) (= received power value / total power value), SIR (Signal Signal Interference Ratio), SINR (Signal Signal Interference Noise Ratio), and the like. Can be mentioned.
　また、制御部２３は、仮想セルに接続するか否かを決定する。制御部２３は例えば、仮想セルに接続するための接続情報と、仮想セルを形成する複数の無線局との間の通信状態を示す情報とに基づいて、仮想セルに接続するか否かを決定する。詳細には例えば、制御部２３は、仮想セルを識別するための識別情報を用いて、仮想セルを形成する複数の無線局との間の通信状態を示す情報を取得し、所定の判定条件を用いて、仮想セルに接続するか否かを判定する。そして制御部２３は、仮想セルに接続する場合、仮想セルに接続するための接続要求を送信し、応答信号を受信して、接続確立のための手順を行い、仮想セルとの接続を確立する。 Also, the control unit 23 determines whether to connect to the virtual cell. For example, the control unit 23 determines whether to connect to the virtual cell based on the connection information for connecting to the virtual cell and the information indicating the communication state between the plurality of radio stations forming the virtual cell. To do. Specifically, for example, the control unit 23 uses the identification information for identifying the virtual cell to acquire information indicating the communication state with a plurality of radio stations forming the virtual cell, and sets a predetermined determination condition. To determine whether to connect to the virtual cell. When connecting to the virtual cell, the control unit 23 transmits a connection request for connecting to the virtual cell, receives a response signal, performs a procedure for establishing the connection, and establishes a connection with the virtual cell. .
　図４は、無線局１０Ａのハードウェア構成を示す図である。図４に示すように、無線局１０Ａは、ハードウェアの構成要素として、例えばアンテナ３１を備えるＲＦ（Radio　Frequency）回路３２と、ＣＰＵ（Central Processing Unit）３３と、ＤＳＰ（Digital　Signal　Processor）３４と、メモリ３５と、ネットワークＩＦ（Interface）３６とを有する。ＣＰＵは、スイッチ等のネットワークＩＦ３６を介して各種信号やデータの入出力が可能なように接続されている。メモリ３５は、例えばＳＤＲＡＭ（Synchronous　Dynamic　Random　Access　Memory）等のＲＡＭ（Random　Access　Memory）、ＲＯＭ（Read　Only　Memory)、及びフラッシュメモリの少なくともいずれかを含み、プログラムや制御情報やデータを格納する。送信部１２及び受信部１１は、例えばＲＦ回路３２、あるいはアンテナ３１およびＲＦ回路３２により実現される。制御部１３は、例えばＣＰＵ３３等の集積回路あるいはＤＳＰ３４等の集積回路により実現される。 FIG. 4 is a diagram illustrating a hardware configuration of the radio station 10A. As shown in FIG. 4, the radio station 10A includes, as hardware components, an RF (Radio Frequency) circuit 32 including an antenna 31, a CPU (Central Processing Unit) 33, a DSP (Digital Signal Processor) 34, and the like. , A memory 35 and a network IF (Interface) 36. The CPU is connected via a network IF 36 such as a switch so that various signals and data can be input and output. The memory 35 includes at least one of RAM (Random Access Memory) such as SDRAM (Synchronous Dynamic Random Access Memory), ROM (Read Only Memory), and flash memory, and stores programs, control information, and data. The transmission unit 12 and the reception unit 11 are realized by the RF circuit 32 or the antenna 31 and the RF circuit 32, for example. The control unit 13 is realized by, for example, an integrated circuit such as the CPU 33 or an integrated circuit such as the DSP 34.
　図５は、無線端末２０のハードウェア構成を示す図である。図５に示すように、無線端末２０は、ハードウェアの構成要素として、例えばアンテナ４１を備えるＲＦ回路４２と、ＣＰＵ４３と、メモリ４４とを有する。さらに、無線端末２０は、ＣＰＵ４３に接続されるＬＣＤ（Liquid　Crystal　Display）等の表示装置を有してもよい。メモリ４４は、例えばＳＤＲＡＭ等のＲＡＭ、ＲＯＭ、及びフラッシュメモリの少なくともいずれかを含み、プログラムや制御情報やデータを格納する。送信部２２及び受信部２１は、例えばＲＦ回路４２、あるいはアンテナ４１およびＲＦ回路４２により実現される。制御部２３は、例えばＣＰＵ４３等の集積回路により実現される。 FIG. 5 is a diagram illustrating a hardware configuration of the wireless terminal 20. As illustrated in FIG. 5, the wireless terminal 20 includes, as hardware components, an RF circuit 42 including an antenna 41, a CPU 43, and a memory 44, for example. Further, the wireless terminal 20 may have a display device such as an LCD (Liquid Crystal Display) connected to the CPU 43. The memory 44 includes at least one of RAM such as SDRAM, ROM, and flash memory, for example, and stores programs, control information, and data. The transmission unit 22 and the reception unit 21 are realized by the RF circuit 42 or the antenna 41 and the RF circuit 42, for example. The control unit 23 is realized by an integrated circuit such as the CPU 43, for example.
　次に、第１実施形態における無線通信システム１の動作を説明する。図６は、無線通信システム１の接続確立の動作を説明するためのシーケンス図であり、図７は、無線通信システム１の接続確立の動作例を説明するための図である。 Next, the operation of the wireless communication system 1 in the first embodiment will be described. FIG. 6 is a sequence diagram for explaining an operation for establishing a connection in the wireless communication system 1, and FIG. 7 is a diagram for explaining an operation example for establishing a connection in the wireless communication system 1.
　まず前提として、無線通信システム１では、上述のように、無線局１０Ａ～Ｂは、ＣｏＭＰ通信が可能に設けられている。なお、無線局１０Ａ～Ｂは異種の通信方式を使用してもよい。また、無線局１０Ａ～Ｂはキャリアアグリゲーション可能な無線局としてもよい。無線端末２０は、無線局１０Ａが形成するセルＣ１０Ａと、無線局１０Ｂに形成するＣ１０Ｂとに存在する。 First, as a premise, in the wireless communication system 1, as described above, the wireless stations 10A to 10B are provided so as to be capable of CoMP communication. Note that the radio stations 10A to 10B may use different communication methods. Further, the radio stations 10A to 10B may be radio stations capable of carrier aggregation. The radio terminal 20 exists in a cell C10A formed by the radio station 10A and a C10B formed in the radio station 10B.
　このとき、通信性能の向上を実現するために、例えば所定の無線端末に対する無線通信リソースの割当てを増やしてスループット向上を図るよう、各通信ポイントの通信態様は比較的短い周期で、ダイナミックに調整される。そして、セル配置や通信状況によって、各通信ポイントの通信態様は無線端末毎に多様に変わり得ることが想定される。例えば、ＣｏＭＰ通信可能な通信ポイントは多数存在する可能性があり、ＣｏＭＰ通信で実際に信号の送信に使用する通信ポイントの数や組み合わせは多様となる。さらに例えば、異種の通信ネットワークの数や組み合わせ、連結可能な無線周波数キャリアの数や組み合わせも、多様となることが想定される。 At this time, in order to improve the communication performance, for example, the communication mode of each communication point is dynamically adjusted at a relatively short cycle so as to increase the allocation by increasing the allocation of radio communication resources to a predetermined radio terminal. The And it is assumed that the communication mode of each communication point can change variously for every radio | wireless terminal by a cell arrangement | positioning and a communication condition. For example, there may be many communication points capable of CoMP communication, and the number and combination of communication points actually used for signal transmission in CoMP communication vary. Furthermore, for example, the number and combination of different types of communication networks and the number and combination of connectable radio frequency carriers are expected to vary.
　このような状況では、この多様に変わり得る通信態様に対応するよう、例えば制御情報を所定の手順でやり取りし、適切な通信態様を選択して切り替える必要がある。このとき、通信態様の切り替えが効率良く行われないと、通信性能の向上を妨げる恐れがある。例えば、一般には、無線端末が１つの無線局との初期接続を確立する手続を行ってから、セル配置や通信状況に応じてＣｏＭＰ通信等の協調連携の実施可否等を判定する手続を行い、判定に応じて無線リソース管理等の協調連携のための手続を行い、通信態様を切り替える必要がある。このように、様々な手続を伴うため、各無線端末について適切な協調連携による通信態様に移行するまでに時間を要することとなる。このために、ユーザパケットの通信開始から比較的短時間のスループットが改善されず、通信性能の向上を妨げる恐れがある。 In such a situation, for example, it is necessary to exchange control information in a predetermined procedure and select and switch an appropriate communication mode so as to correspond to the communication modes that can be variously changed. At this time, if the communication mode is not switched efficiently, the communication performance may be prevented from improving. For example, generally, after a wireless terminal performs a procedure for establishing an initial connection with one wireless station, a procedure for determining whether or not to perform cooperative cooperation such as CoMP communication according to cell arrangement and communication status is performed. Depending on the determination, it is necessary to switch the communication mode by performing a procedure for cooperative cooperation such as radio resource management. Thus, since various procedures are involved, it takes time to shift to a communication mode based on appropriate cooperative cooperation for each wireless terminal. For this reason, the throughput in a relatively short time from the start of communication of user packets is not improved, and there is a risk that improvement in communication performance may be hindered.
　そこで、第１実施形態では、以下のように接続確立の動作が行われる。 Therefore, in the first embodiment, the operation for establishing a connection is performed as follows.
　図６に示すように、無線局１０Ａは、仮想セルの構成情報を設定し、無線局１０Ｂに通知する（Ｓ１）。具体的には、図７に示すように、無線局１０Ａ～Ｂにより形成される仮想セルＶＣ１が設定される。仮想セルＶＣ１の構成情報は例えば、仮想セルＶＣ１を識別するための識別情報や、無線端末２０が仮想セルＶＣ１に接続要求するか否か判定するための判定条件や、仮想セルＶＣ１に接続するための接続要求を送受信する無線リソースエレメントの配置を含む。仮想セルＶＣ１を識別するための識別情報は、仮想セルＶＣ１を形成する無線局１０Ａ～Ｂのそれぞれの識別情報を含む。判定条件は例えば、無線局１０Ａと無線局１０Ｂとの協調連携により通信性能が向上すると想定される条件であり、無線局１０Ａ～Ｂからの受信レベルや、無線局１０Ａからの受信レベルと無線局１０Ｂからの受信レベルとの関係を含む。 As shown in FIG. 6, the radio station 10A sets the virtual cell configuration information and notifies the radio station 10B (S1). Specifically, as shown in FIG. 7, a virtual cell VC1 formed by the radio stations 10A to 10B is set. The configuration information of the virtual cell VC1 includes, for example, identification information for identifying the virtual cell VC1, determination conditions for determining whether the wireless terminal 20 requests connection to the virtual cell VC1, and connection to the virtual cell VC1. Including an arrangement of radio resource elements that transmit and receive a connection request. The identification information for identifying the virtual cell VC1 includes identification information of each of the radio stations 10A to 10B forming the virtual cell VC1. The determination condition is, for example, a condition that the communication performance is assumed to be improved by cooperative cooperation between the radio station 10A and the radio station 10B. The reception level from the radio stations 10A to 10B, the reception level from the radio station 10A, and the radio station The relationship with the reception level from 10B is included.
　次に、無線局１０Ａ～Ｂは、仮想セルＶＣ１の構成情報を送信する（Ｓ２）。仮想セルＶＣ１の構成情報は、システム情報あるいはセル共通の制御情報として無線局１０Ａ～Ｂからそれぞれ報知される。 Next, the radio stations 10A to 10B transmit the configuration information of the virtual cell VC1 (S2). The configuration information of the virtual cell VC1 is broadcast from the radio stations 10A to 10B as system information or cell-common control information.
　次に、無線端末２０は、仮想セルＶＣ１との接続を決定する（Ｓ３）。具体的には無線端末２０は、仮想セルＶＣ１の識別情報により、仮想セルＶＣ１を形成する無線局１０Ａ～Ｂからの信号の受信レベルを測定する。そして、測定した受信レベルと、仮想セルＶＣ１の構成情報に設定される判定条件とにより、仮想セルＶＣ１に接続要求するか否か決定する。図７の例では、例えば、無線局１０Ａ～Ｂからの受信レベルが所定範囲内にあり、かつ無線局１０Ａからの受信レベルと無線局１０Ｂからの受信レベルとの差が所定範囲内にある場合に、仮想セルＶＣ１に接続要求すると判定する。このように、無線局１０Ａと無線局１０Ｂとの協調連携により通信性能が向上すると想定される場合に、仮想セルＶＣ１に接続要求すると判定される。なお例えば、仮想セルＶＣ１に接続要求するための判定条件を満たさず、セルＣ１０Ａに接続要求するための判定条件を満たす場合には、セルＣ１０Ａへの接続が決定される。 Next, the wireless terminal 20 determines connection with the virtual cell VC1 (S3). Specifically, the radio terminal 20 measures the reception level of signals from the radio stations 10A to 10B forming the virtual cell VC1 based on the identification information of the virtual cell VC1. Then, whether to make a connection request to the virtual cell VC1 is determined based on the measured reception level and the determination condition set in the configuration information of the virtual cell VC1. In the example of FIG. 7, for example, the reception level from the radio stations 10A to 10B is within a predetermined range, and the difference between the reception level from the radio station 10A and the reception level from the radio station 10B is within the predetermined range. It is determined that a connection request is made to the virtual cell VC1. Thus, when communication performance is assumed to be improved by cooperative cooperation between the radio station 10A and the radio station 10B, it is determined that a connection request is made to the virtual cell VC1. For example, when the determination condition for requesting connection to the virtual cell VC1 is not satisfied and the determination condition for requesting connection to the cell C10A is satisfied, the connection to the cell C10A is determined.
　次に、無線端末２０は、仮想セルＶＣ１との接続要求を送信する（Ｓ４）。具体的には、仮想セルＶＣ１との接続要求は、仮想セルＶＣ１の構成情報に設定される無線リソースエレメントを使用して送信される。例えば、仮想セルＶＣ１が設定される場合、セルＣ１０Ａ，Ｂへの接続確立のために準備されている無線リソースエレメントの一部を、仮想セルＶＣ１に割当てる。そして、無線端末２０から、この割当てられた無線リソースエレメントで接続要求を送信することで、例えば接続要求を受信した無線局１０Ａは、仮想セルＶＣ１への接続要求であることを把握することができる。これにより、セルＣ１０Ａへの接続確立へ移行せずに、仮想セルＶＣ１との接続の準備が実行され、協調連携による通信へ移行される。 Next, the wireless terminal 20 transmits a connection request with the virtual cell VC1 (S4). Specifically, the connection request with the virtual cell VC1 is transmitted using a radio resource element set in the configuration information of the virtual cell VC1. For example, when the virtual cell VC1 is set, a part of radio resource elements prepared for establishing a connection to the cells C10A and B is allocated to the virtual cell VC1. Then, by transmitting a connection request from the wireless terminal 20 using the allocated wireless resource element, for example, the wireless station 10A that has received the connection request can recognize that it is a connection request to the virtual cell VC1. . As a result, preparation for connection with the virtual cell VC1 is performed without shifting to establishment of connection to the cell C10A, and shift to communication by cooperative cooperation.
　次に、無線局１０Ａ～Ｂは、仮想セルＶＣ１との接続要求を受信し、無線端末２０と仮想セルＶＣ１との接続を準備する（Ｓ５）。具体的には例えば、無線局１０Ａが接続要求を受信し、無線端末２０との接続確立のための情報を、無線局１０Ａから無線局１０Ｂに通知する。 Next, the radio stations 10A to 10B receive a connection request with the virtual cell VC1, and prepare for connection between the radio terminal 20 and the virtual cell VC1 (S5). Specifically, for example, the wireless station 10A receives a connection request and notifies the wireless station 10B of information for establishing a connection with the wireless terminal 20 from the wireless station 10A.
　そして、無線端末２０と無線局１０Ａ～Ｂとの間で接続確立を実行する（Ｓ６）。これにより、無線局１０Ａと無線局１０Ｂとの協調連携により通信性能が向上すると想定される場合、例えば無線端末２０が１つの無線局１０Ａとの初期接続を確立してから協調連携の実施可否を判定して協調連携による通信へ移行する場合に比較して、迅速に協調連携による通信を開始することができる。すなわち、効率良く協調連携への切り替えが行われる。 Then, connection establishment is executed between the wireless terminal 20 and the wireless stations 10A and 10B (S6). Thereby, when it is assumed that the communication performance is improved by cooperative cooperation between the wireless station 10A and the wireless station 10B, for example, whether or not the cooperative cooperation can be performed after the wireless terminal 20 establishes an initial connection with one wireless station 10A. Compared with the case of determining and shifting to communication by cooperative cooperation, communication by cooperative cooperation can be started quickly. That is, switching to cooperative cooperation is performed efficiently.
　以上により、第１実施形態によれば、無線通信システム１において、無線端末２０と無線局１０Ａ～Ｂとの間の通信態様を効率良く切り替えて、通信性能を向上できる。 As described above, according to the first embodiment, in the wireless communication system 1, it is possible to efficiently switch the communication mode between the wireless terminal 20 and the wireless stations 10A to 10B and improve the communication performance.
　第１実施形態において、無線端末２０は、無線通信システム１の他の無線局と同期して、仮想セルに接続するための情報を該他の無線局から受信し、無線局１０Ａ～Ｂにより形成される仮想セルとの接続確立を実行するものとしてもよい。 In the first embodiment, the radio terminal 20 receives information for connecting to the virtual cell from the other radio stations in synchronization with the other radio stations of the radio communication system 1, and is formed by the radio stations 10A to 10B. The connection establishment with the virtual cell to be performed may be executed.
　第１実施形態において、無線通信システム１は、２つの無線局を有するものとしたが、無線局の数は任意である。また、ＣｏＭＰ通信可能な無線局とＣｏＭＰ通信可能でない無線局とが混在してもよい。また、キャリアアグリゲーション動作が可能な無線局と可能でない無線局とが混在してもよい。また、異なる種類の通信方式を用いる無線局が混在してもよい。 In the first embodiment, the wireless communication system 1 has two wireless stations, but the number of wireless stations is arbitrary. Also, a radio station capable of CoMP communication and a radio station not capable of CoMP communication may be mixed. Further, a radio station capable of performing a carrier aggregation operation and a radio station not capable of performing a carrier aggregation operation may be mixed. Further, radio stations using different types of communication methods may be mixed.
　第１実施形態において、無線通信システム１は、１つの無線端末を有するものとしたが、無線端末の数は任意である。また、ＣｏＭＰ通信可能な無線端末とＣｏＭＰ通信可能でない無線端末とが混在してもよい。また、キャリアアグリゲーション動作が可能な無線端末と可能でない無線端末とが混在してもよい。また、異なる種類の通信方式で通信可能な無線端末と可能でない無線端末とが混在してもよい。 In the first embodiment, the wireless communication system 1 has one wireless terminal, but the number of wireless terminals is arbitrary. Also, wireless terminals capable of CoMP communication and wireless terminals not capable of CoMP communication may be mixed. In addition, wireless terminals that can perform carrier aggregation operations and wireless terminals that cannot perform carrier aggregation operations may be mixed. Also, wireless terminals that can communicate with different types of communication methods and wireless terminals that are not capable of communicating may be mixed.
［第２実施形態］
　次に、第２実施形態に係る無線通信システムについて、図８～１７を参照して説明する。図８に示すように、第２実施形態に係る無線通信システム１Ａは、無線局１０Ａ～Ｂの代わりに、後述の図９に示す無線局５０Ａ～Ｃを有し、無線端末２０の代わりに、後述の図１０に示す無線端末７０Ａ～Ｃ（ＵＥ＃１～３とも記載する）を有する。第２実施形態に係る無線通信システム１Ａの全体的構成は、図１に示す無線通信システム１と同様である。例えば、無線局５０Ａ～Ｃはそれぞれ、有線接続あるいは無線接続を介してネットワーク装置３と接続され、ネットワーク装置３は有線接続あるいは無線接続を介してネットワーク２に接続される。そして、無線局５０Ａ～Ｃは、ネットワーク装置３及びネットワーク２を介して、データや制御情報を送受信可能に設けられている。 [Second Embodiment]
Next, a radio communication system according to the second embodiment will be described with reference to FIGS. As shown in FIG. 8, the wireless communication system 1A according to the second embodiment has wireless stations 50A to 50C shown in FIG. 9 described later instead of the wireless stations 10A to 10B, and instead of the wireless terminal 20, Wireless terminals 70A to 70C (also referred to as UE # 1 to UE3) shown in FIG. The overall configuration of a wireless communication system 1A according to the second embodiment is the same as that of the wireless communication system 1 shown in FIG. For example, each of the wireless stations 50A to 50C is connected to the network device 3 via a wired connection or a wireless connection, and the network device 3 is connected to the network 2 via a wired connection or a wireless connection. The radio stations 50A to 50C are provided so as to be able to transmit and receive data and control information via the network device 3 and the network 2.
　また、無線局５０Ａ～Ｃはそれぞれ、アンテナを有し、通信ポイントに相当する。無線局５０Ａ～ＣはそれぞれセルＣ５０Ａ～Ｃを形成している。無線局５０Ａ～Ｃは、無線局５０Ａ～Ｃ間で有線接続あるいは無線接続を介して通信を行う。また、無線局５０Ａ～Ｃは、無線端末ＵＥ＃１～３に対してＣｏＭＰ通信が可能である。 Further, each of the radio stations 50A to 50C has an antenna and corresponds to a communication point. Radio stations 50A-C form cells C50A-C, respectively. The radio stations 50A to 50C communicate with each other via a wired connection or a wireless connection. The radio stations 50A to 50C can perform CoMP communication with the radio terminals UE # 1 to UE # 3.
　以下の説明では、無線端末ＵＥ＃１は無線局５０Ａが形成するセルＣ５０Ａに存在し、無線端末ＵＥ＃２は無線局５０Ａ，Ｂが形成するセルＣ５０Ａ，Ｂに存在し、無線端末ＵＥ＃３は無線局５０Ｂが形成するセルＣ５０Ｂに存在する。 In the following description, the radio terminal UE # 1 exists in the cell C50A formed by the radio station 50A, the radio terminal UE # 2 exists in the cells C50A and B formed by the radio stations 50A and B, and the radio terminal UE # 3. Exists in the cell C50B formed by the radio station 50B.
　図９は、第２実施形態に係る無線通信システム１Ａの無線局５０Ａの機能的構成を示すブロック図である。なお、無線局５０Ｂ～Ｃの機能的構成およびハードウェア構成は、無線局５０Ａの機能的構成及びハードウェア構成と同様である。 FIG. 9 is a block diagram showing a functional configuration of the radio station 50A of the radio communication system 1A according to the second embodiment. The functional configuration and hardware configuration of the radio stations 50B to 50C are the same as the functional configuration and hardware configuration of the radio station 50A.
　図９に示すように、無線局５０Ａは、受信アンテナ５１と、受信ＲＦ部５２と、ＦＦＴ（Fast Fourier Transform）部５３と、物理チャネル分離部５４と、信号復調部５５と、チャネル推定部５６と、受信レベル測定部５７と、通信制御部５８と、上位レイヤデータ処理部５９と、信号生成部６０と、参照信号生成部６１と、物理チャネル多重部６２と、ＩＦＦＴ（Inverse Fast Fourier Transform）部６３と、送信ＲＦ部６４と、送信アンテナ６５と、を有する。 As illustrated in FIG. 9, the radio station 50A includes a reception antenna 51, a reception RF unit 52, an FFT (Fast Fourier Transform) unit 53, a physical channel separation unit 54, a signal demodulation unit 55, and a channel estimation unit 56. A reception level measurement unit 57, a communication control unit 58, an upper layer data processing unit 59, a signal generation unit 60, a reference signal generation unit 61, a physical channel multiplexing unit 62, and an IFFT (Inverse Fast Fourier Transform). Unit 63, transmission RF unit 64, and transmission antenna 65.
　受信アンテナ５１は、無線信号を受信して、受信ＲＦ部５２に出力する。受信アンテナ５１は例えば、複数のアンテナ（物理アンテナ）を含む。また、受信アンテナ５１は、送信アンテナ６５と共用として、送信／受信切替え部等により送信と受信とを切り替えて構成するものとしてもよい。受信アンテナ５１は、例えば上りのデータチャネルや制御チャネル上を伝送される上り信号（データ信号や制御信号）を受信する。信号を受信する物理チャネルとしては例えば、ＰＲＡＣＨ（Physical Random Access Channel）や、ＰＵＳＣＨ（Physical Uplink Shared Channel）や、ＰＵＣＣＨ（Physical Uplink Control Channel）が挙げられる。受信される信号としては例えば、無線端末ＵＥ＃１～３からの接続確立のためのＲＡＣＨ（Random Access Channel）信号や、無線端末ＵＥ＃１～３での受信レベルを示す信号（例えば、RSRP Report）や、チャネル推定や復調のための参照信号が挙げられる。 The reception antenna 51 receives a radio signal and outputs it to the reception RF unit 52. The reception antenna 51 includes, for example, a plurality of antennas (physical antennas). The reception antenna 51 may be configured to be shared with the transmission antenna 65 and switched between transmission and reception by a transmission / reception switching unit or the like. The reception antenna 51 receives, for example, an uplink signal (data signal or control signal) transmitted on an uplink data channel or control channel. Examples of the physical channel that receives the signal include PRACH (Physical Random Access Channel), PUSCH (Physical Uplink Shared Channel), and PUCCH (Physical Uplink Control Channel). Examples of received signals include RACH (Random Access Channel) signals for establishing connections from the radio terminals UE # 1 to UE3 and signals indicating reception levels at the radio terminals UE # 1 to UE3 (for example, RSRP Report). ) And reference signals for channel estimation and demodulation.
　受信ＲＦ部５２は、受信信号にＡ／Ｄ（Analog to Digital）変換等の処理を行う。ＦＦＴ部５３は、デジタル信号にＦＦＴ処理を行う。物理チャネル分離部５４は、ＦＦＴ処理された信号から、各チャネルの信号を分離する。物理チャネル分離部５４は、上り信号に含まれる上り参照信号を抽出する。上り参照信号は例えば、上りの周波数毎のチャネル推定に用いられるＳＲＳ（Sounding Reference Signal）や、上りの信号の復調のためのＤＭ－ＲＳ（DeModulation RS）を含む。信号復調部５５は、予め通知される或いは格納される制御情報や、復調のための参照信号に基づいて、分離された各チャネルの信号の復調処理を行う。チャネル推定部５６は、予め通知される或いは格納される制御情報や、受信した参照信号に基づいて、チャネルの伝搬状態を示すチャネル推定値を取得する。復調処理された信号はチャネル推定値に基づいて復号処理される。復号処理されて取得されたデータ信号や制御信号は、通信制御部５８に出力される。また、データ信号の復号結果として、ＡＣＫ（ACKnowledgement）／ＮＡＣＫ（Negative ACKnowledgement）が通信制御部５８に出力される。 The reception RF unit 52 performs processing such as A / D (Analog-to-Digital) conversion on the received signal. The FFT unit 53 performs FFT processing on the digital signal. The physical channel separation unit 54 separates each channel signal from the FFT-processed signal. The physical channel separation unit 54 extracts an uplink reference signal included in the uplink signal. The uplink reference signal includes, for example, SRS (Sounding Reference Signal) used for channel estimation for each uplink frequency and DM-RS (DeModulation RS) for demodulation of the uplink signal. The signal demodulator 55 demodulates the signal of each separated channel based on control information notified or stored in advance or a reference signal for demodulation. The channel estimation unit 56 acquires a channel estimation value indicating a channel propagation state based on control information notified or stored in advance or a received reference signal. The demodulated signal is decoded based on the channel estimation value. The data signal and control signal acquired through the decoding process are output to the communication control unit 58. Further, ACK (ACKnowledgement) / NACK (Negative ACKnowledgement) is output to the communication control unit 58 as a decoding result of the data signal.
　受信レベル測定部５７は、受信した信号から受信レベル（上り受信電力や上り受信品質）を測定する。受信レベルとしては例えば、ＲＳＲＰ、ＲＳＲＱ、ＳＩＲ、ＳＩＮＲ等が挙げられる。 The reception level measurement unit 57 measures the reception level (uplink reception power and uplink reception quality) from the received signal. Examples of the reception level include RSRP, RSRQ, SIR, SINR, and the like.
　通信制御部５８は、有線接続あるいは無線接続を介して、ネットワーク装置や他の無線局とデータや制御情報の送受信を行う。また、通信制御部５８は、無線端末ＵＥ＃１～３とのアクセスの管理や、信号を送信する送信電力の制御等の通信制御を行う。送信電力の制御は例えば、通信ポイントとの間の伝搬ロス（パスロス）を補償するオープンループ制御や、適応変調制御や、ＴＰＣ（Transmission Power Control）コマンドによるクローズドループ制御によって行われる。また、通信制御は例えば、ＣｏＭＰ通信のための処理や、キャリアアグリゲーションのための処理や、ハンドオーバ（Inter-Cell, Inter-Frequency, Inter-Rat等）のための処理を含む。その他、通信制御部５８の詳細については後述する。 The communication control unit 58 transmits / receives data and control information to / from the network device and other wireless stations via a wired connection or a wireless connection. Further, the communication control unit 58 performs communication control such as management of access to the radio terminals UE # 1 to UE # 3 and control of transmission power for transmitting signals. The transmission power is controlled by, for example, open loop control that compensates for a propagation loss (path loss) between communication points, adaptive modulation control, and closed loop control using a TPC (Transmission Power Control) command. The communication control includes, for example, processing for CoMP communication, processing for carrier aggregation, and processing for handover (Inter-Cell, Inter-Frequency, Inter-Rat, etc.). The details of the communication control unit 58 will be described later.
　上位レイヤデータ処理部５９は、復号処理されたデータ信号のリオーダリング処理等を行い、上りユーザデータを取得する。また、上位レイヤデータ処理部５９は、ネットワーク装置や他の無線局から取得される下りユーザデータや、送信する制御情報を処理して、送信パケットを生成する。 The upper layer data processing unit 59 performs reordering processing of the decoded data signal and acquires uplink user data. Further, the upper layer data processing unit 59 processes downlink user data acquired from a network device or another wireless station and control information to be transmitted to generate a transmission packet.
　信号生成部６０は、送信パケットを符号化・変調して物理チャネル多重部６２に出力する。また、信号生成部６０は、個別制御チャネル上を伝送する制御信号を生成して物理チャネル多重部６２に出力する。参照信号生成部６１は、下り参照信号を生成して物理チャネル多重部６２に出力する。下り参照信号は、例えば下りのセル固有のＣＲＳ（Cell-specific Reference Signal）や、下りのＣＳＩ－ＲＳ（Channel State Information Reference Signal）や、下りのチャネル推定や信号の復調のために用いられる無線端末個別の参照信号（ＤＭ－ＲＳ）を含む。ＣＲＳは下りの通信品質の測定や、下りの信号の復調に用いられ、セル識別情報（セルＩＤ）に対応付けて設定される。ＣＳＩ－ＲＳは下りの通信品質の測定に用いられ、例えば通信ポイント毎に設定することが可能である。 The signal generator 60 encodes and modulates the transmission packet and outputs it to the physical channel multiplexer 62. In addition, the signal generation unit 60 generates a control signal transmitted on the dedicated control channel and outputs the control signal to the physical channel multiplexing unit 62. The reference signal generator 61 generates a downlink reference signal and outputs it to the physical channel multiplexer 62. The downlink reference signal is a radio terminal used for downlink cell-specific CRS (Cell-specific Reference Signal), downlink CSI-RS (Channel State Information Reference Signal), downlink channel estimation and signal demodulation, for example. Includes an individual reference signal (DM-RS). The CRS is used for measurement of downlink communication quality and demodulation of downlink signals, and is set in association with cell identification information (cell ID). CSI-RS is used for measurement of downlink communication quality, and can be set for each communication point, for example.
　物理チャネル多重部６２は、通信制御部５８のスケジューリングに応じて、符号化・変調された送信パケットや制御信号や参照信号を、物理チャネルの無線リソースに割当てる。ＩＦＦＴ部６３は、多重後の信号にＩＦＦＴ処理を行う。送信ＲＦ部６４は、ＩＦＦＴ処理後の信号に、Ｄ／Ａ変換や、歪補償処理や、増幅処理等を行って、送信アンテナ６５に出力する。 The physical channel multiplexing unit 62 allocates the encoded / modulated transmission packet, control signal, and reference signal to the physical channel radio resource according to the scheduling of the communication control unit 58. The IFFT unit 63 performs IFFT processing on the multiplexed signal. The transmission RF unit 64 performs D / A conversion, distortion compensation processing, amplification processing, and the like on the signal after IFFT processing and outputs the result to the transmission antenna 65.
　送信アンテナ６５は、送信ＲＦ部６４から入力される無線信号を送信する。なお、送信アンテナ６５は例えば、複数のアンテナを含む。送信アンテナ６５は、例えば下りのデータチャネルや制御チャネル上を伝送される下り信号（データ信号や制御信号）を送信する。信号を送信する物理チャネルとしては例えば、報知チャネルＰＢＣＨ（Physical Broadcast Channel）や、ＰＭＣＨ（Physical Multicast Channel）や、共有チャネルＰＤＳＣＨ（Physical Downlink Shared Channel）や、個別制御チャネルＰＤＣＣＨ（Physical Downlink Control Channel）や、Ｅ－ＰＤＣＣＨ（Enhanced - Physical Downlink Control Channel）が挙げられる。送信される信号としては例えば、無線端末ＵＥ＃１～３へ呼の着信があった場合に無線端末ＵＥ＃１～３を呼び出すためのＰＣＨ（Paging Channel）信号や、ＲＡＣＨ信号への応答信号（ＲＡＲ，Random Access Response）が挙げられる。また、送信される信号としては例えば、無線局５０Ａでの受信レベルを示す信号や、上り送信電力の制御のための制御信号（例えば、下り送信電力情報や、ＴＰＣコマンド等）が挙げられる。また、送信する信号は例えば、チャネル推定や復調のために用いられる無線端末個別の参照信号や、無線端末個別の参照信号の送信に準備される無線リソースを示す複数の構成情報や、複数の構成情報のそれぞれが示す無線リソースについての使用に関する使用モードを指定する信号を含む。制御信号としては例えば、接続中の無線端末に個別制御チャネル上で伝送されるＬ１／Ｌ２シグナリングや、接続中の無線端末に共有チャネル上で伝送されるＲＲＣ（Radio Resource Control）シグナリングが挙げられる。また、制御信号としては例えば、ＭＩＢ（Master Information Block）やＳＩＢ（System Information Block）に格納されて、報知チャネル又は報知チャネルで指定される共有チャネル上で伝送されるシステム情報が挙げられる。 The transmission antenna 65 transmits a radio signal input from the transmission RF unit 64. Note that the transmission antenna 65 includes, for example, a plurality of antennas. The transmission antenna 65 transmits, for example, a downlink signal (data signal or control signal) transmitted on a downlink data channel or control channel. Examples of physical channels that transmit signals include broadcast channels PBCH (Physical road Broadcast Channel), PMCH (Physical Multicast Channel), shared channel PDSCH (Physical Downlink Shared Channel), dedicated control channel PDCCH (Physical Downlink Control Channel), and the like. E-PDCCH (Enhanced--Physical-Downlink-Control-Channel). As a signal to be transmitted, for example, when a call arrives at the radio terminals UE # 1 to UE # 3, a PCH (Paging Channel) signal for calling the radio terminals UE # 1 to UE3, or a response signal to the RACH signal ( RAR, Random Access Response). Further, examples of the signal to be transmitted include a signal indicating the reception level at the radio station 50A, and a control signal (for example, downlink transmission power information, a TPC command, etc.) for controlling the uplink transmission power. The signal to be transmitted is, for example, a reference signal for each wireless terminal used for channel estimation or demodulation, a plurality of configuration information indicating a radio resource prepared for transmission of a reference signal for each wireless terminal, or a plurality of configurations Each of the information includes a signal that specifies a use mode related to use of the radio resource indicated by the information. Examples of the control signal include L1 / L2 signaling transmitted on the dedicated wireless channel to the connected wireless terminal and RRC (Radio Resource Control) signaling transmitted on the shared channel to the connected wireless terminal. The control signal includes, for example, system information that is stored in MIB (Master Information Block) or SIB (System Information Block) and transmitted on a broadcast channel or a shared channel designated by the broadcast channel.
　以下、通信制御部５８の処理について詳述する。 Hereinafter, the processing of the communication control unit 58 will be described in detail.
　通信制御部５８は、無線端末ＵＥ＃１～３とのアクセスの管理や、無線端末ＵＥ＃１～３への無線リソースの割当て等のスケジューリングを行う。 The communication control unit 58 performs management of access to the radio terminals UE # 1 to UE3 and scheduling of allocation of radio resources to the radio terminals UE # 1 to UE3.
　通信制御部５８は例えば、周辺無線局５０Ｂ～Ｃと情報をやり取りし、仮想セルの構成情報を設定する。通信制御部５８は例えば、セル配置や、各セルで使用される無線通信方式や、各セルで使用される無線周波数キャリア等に基づいて、取り得る１又は複数の仮想セルの構成情報を設定する。また、通信制御部５８は例えば、無線局５０Ａ～Ｃが接続中の無線端末の数、無線局５０Ａ～Ｃと接続中の無線端末との間の通信レベル、無線局５０Ａ～Ｃからデータを送信する通信モード、の少なくともいずれかを考慮して、仮想セルの構成情報を設定してもよい。無線局５０Ａ～Ｃと無線端末ＵＥ＃１～３との間の通信レベルは例えば、上り参照信号あるいは下り参照信号から測定される。通信レベルは例えば、無線端末ＵＥ＃１～３から報告されてもよい。あるいは、通信レベルは例えば、無線局５０Ａと無線端末ＵＥ＃１～３との間の通信レベルを無線局５０Ａで測定すると共に、無線局５０Ｂと無線端末ＵＥ＃１～３との間の通信レベルを無線局５０Ｂで測定し、無線局５０Ｃと無線端末ＵＥ＃１～３との間の通信レベルを無線局５０Ｃで測定し、無線局５０Ｂ～Ｃから無線局５０Ａに通知してもよい。また、通信モードとしては例えば、シングルアンテナ通信、ＭＩＭＯ通信、およびＣｏＭＰ通信が挙げられる。 The communication control unit 58 exchanges information with the peripheral radio stations 50B to 50C, for example, and sets the virtual cell configuration information. The communication control unit 58 sets configuration information of one or a plurality of virtual cells that can be taken based on, for example, the cell arrangement, the radio communication scheme used in each cell, the radio frequency carrier used in each cell, and the like. . The communication control unit 58 also transmits, for example, the number of wireless terminals to which the wireless stations 50A to 50C are connected, the communication level between the wireless stations 50A to 50C and the connected wireless terminals, and data transmitted from the wireless stations 50A to 50C. The configuration information of the virtual cell may be set in consideration of at least one of the communication modes to be performed. The communication level between the radio stations 50A to 50C and the radio terminals UE # 1 to UE # 3 is measured from, for example, an uplink reference signal or a downlink reference signal. The communication level may be reported from the radio terminals UE # 1 to UE # 3, for example. Alternatively, for example, the communication level between the radio station 50A and the radio terminals UE # 1 to 3 is measured by the radio station 50A, and the communication level between the radio station 50B and the radio terminals UE # 1 to UE3 is measured. May be measured by the radio station 50B, the communication level between the radio station 50C and the radio terminals UE # 1 to UE # 3 may be measured by the radio station 50C, and notified from the radio stations 50B to 50A to the radio station 50A. Examples of the communication mode include single antenna communication, MIMO communication, and CoMP communication.
　仮想セルの構成情報は例えば、所定の制御タイミングで更新されてもよい。また例えば、仮想セルの構成情報は、予め格納されたあるいは設定された構成情報の候補から、所定の制御タイミングで選択されてもよい。 The virtual cell configuration information may be updated at a predetermined control timing, for example. Further, for example, the configuration information of the virtual cell may be selected at a predetermined control timing from candidates for configuration information stored or set in advance.
　仮想セルの構成情報は、無線局５０Ａと、自局周辺の他の無線局とで、共通に使用される。自局周辺の他の無線局は、ＣｏＭＰ通信可能な他の無線局５０Ｂ～Ｃを含む。 The virtual cell configuration information is commonly used by the radio station 50A and other radio stations around the own station. Other radio stations in the vicinity of the own station include other radio stations 50B to 50C capable of CoMP communication.
　仮想セルの構成情報は例えば、無線局５０Ａで設定してもよく、無線局５０Ｂ～Ｃで設定してもよく、ネットワーク装置３やネットワーク２上の他の装置が無線局５０Ａ～Ｃと情報をやり取りして設定してもよい。また、仮想セルの構成情報は例えば、無線局５０Ａ～Ｃのいずれかの無線局から他の無線局へ有線通信あるいは無線通信を介して通知されてもよく、ネットワーク装置３やネットワーク２上の他の装置から無線局５０Ａ～Ｃに通知してもよい。また、仮想セルの構成情報自体を通知する代わりに、予め格納されたあるいは設定された構成情報の候補から、所定の仮想セルの構成情報を選択するための情報を通知してもよい。また、仮想セルの構成情報は例えば、ネットワーク装置３やネットワーク２上の他の装置に格納され、所定の制御タイミングで無線局５０Ａ～Ｃからアクセスして取得するようにしてもよい。また、仮想セルの構成情報自体を通知する代わりに、格納された仮想セルの構成情報にアクセスするための情報を通知してもよい。 For example, the configuration information of the virtual cell may be set by the radio station 50A or may be set by the radio stations 50B to C, and other devices on the network device 3 or the network 2 may exchange information with the radio stations 50A to 50C. You may set by exchanging. Further, the configuration information of the virtual cell may be notified from one of the radio stations 50A to 50C to another radio station via wired communication or wireless communication. May be notified to the radio stations 50A to 50C. Further, instead of notifying the virtual cell configuration information itself, information for selecting predetermined virtual cell configuration information from candidates of configuration information stored or set in advance may be notified. Further, the configuration information of the virtual cell may be stored in, for example, the network device 3 or another device on the network 2 and may be obtained by accessing from the radio stations 50A to 50C at a predetermined control timing. Further, instead of notifying the virtual cell configuration information itself, information for accessing the stored virtual cell configuration information may be notified.
　そして通信制御部５８は、無線端末ＵＥ＃１～３から仮想セルに接続するための接続要求を受信すると、仮想セルとの無線端末ＵＥ＃１～３との接続を準備する。詳細には例えば、通信制御部５８は、仮想セルを形成する他の無線局との間で制御情報をやり取りして、接続のためのパラメータを準備する。例えば通信制御部５８は、無線端末ＵＥ＃１～３との接続確立のための情報を、仮想セルを形成する他の無線局に通知する。または、通信制御部５８は、無線端末ＵＥ＃１～３との接続確立のための情報を所定の場所に格納し、格納した情報にアクセスするための情報を、仮想セルを形成する他の無線局に通知してもよい。 And the communication control part 58 will prepare the connection with radio | wireless terminal UE # 1-3 with a virtual cell, if the connection request | requirement for connecting to a virtual cell is received from radio | wireless terminal UE # 1-3. Specifically, for example, the communication control unit 58 exchanges control information with other wireless stations that form a virtual cell, and prepares parameters for connection. For example, the communication control unit 58 notifies information for establishing connections with the radio terminals UE # 1 to UE # 3 to other radio stations forming the virtual cell. Alternatively, the communication control unit 58 stores information for establishing connections with the radio terminals UE # 1 to UE3 in a predetermined location, and transmits information for accessing the stored information to other radios forming the virtual cell. You may notify the station.
　そして通信制御部５８は、無線端末との間で制御情報をやり取りして接続を確立する。同様に、仮想セルを形成する他の無線局も、無線端末ＵＥ＃１～３との間で制御情報をやり取りして接続を確立する。 The communication control unit 58 establishes a connection by exchanging control information with the wireless terminal. Similarly, other radio stations forming the virtual cell also exchange control information with the radio terminals UE # 1 to UE # 3 to establish a connection.
　図１０は、第２実施形態の無線端末７０Ａの機能的構成を示すブロック図である。図１０に示すように、無線端末７０Ａは、受信アンテナ７１と、受信ＲＦ部７２と、ＦＦＴ部７３と、物理チャネル分離部７４と、信号復調部７５と、チャネル推定部７６と、受信レベル測定部７７と、通信制御部７８と、上位レイヤデータ処理部７９と、信号生成部８０と、参照信号生成部８１と、物理チャネル多重部８２と、ＩＦＦＴ部８３と、送信ＲＦ部８４と、送信アンテナ８５とを有する。なお、無線端末７０Ｂ～Ｃの機能的構成およびハードウェア構成は、無線端末７０Ａの機能的構成及びハードウェア構成と同様である。 FIG. 10 is a block diagram showing a functional configuration of the wireless terminal 70A of the second embodiment. As shown in FIG. 10, the radio terminal 70A includes a reception antenna 71, a reception RF unit 72, an FFT unit 73, a physical channel separation unit 74, a signal demodulation unit 75, a channel estimation unit 76, and a reception level measurement. Unit 77, communication control unit 78, upper layer data processing unit 79, signal generation unit 80, reference signal generation unit 81, physical channel multiplexing unit 82, IFFT unit 83, transmission RF unit 84, transmission And an antenna 85. The functional configuration and hardware configuration of the wireless terminals 70B to 70C are the same as the functional configuration and hardware configuration of the wireless terminal 70A.
　受信アンテナ７１は、無線信号を受信して、受信ＲＦ部７２に出力する。受信アンテナ７１は例えば、複数のアンテナを含む。また、受信アンテナ７１は、送信アンテナ８５と共用として、送信／受信切替え部等により送信と受信とを切り替えて構成するものとしてもよい。受信アンテナ７１は、例えば上りのデータチャネルや制御チャネル上を伝送される上り信号（データ信号や制御信号）を受信する。受信される信号としては例えば、無線端末７０Ａへ呼の着信があった場合に無線端末７０Ａを呼び出すためのＰＣＨ信号や、無線端末７０ＡからのＲＡＣＨ信号への応答信号が挙げられる。また、受信される信号としては例えば、無線局５０Ａ～Ｃでの受信レベルを示す信号や、上り送信電力の制御のための制御信号（例えば、下り送信電力情報や、ＴＰＣコマンド等）が挙げられる。また、受信される信号は例えば、チャネル推定や復調のために用いられる無線端末個別の参照信号や、参照信号の送信に準備される無線リソースを示す構成情報を含む。また、送信する信号は、セルＣ５０Ａの構成情報（セルＣ５０Ａに接続するための接続情報）や、セルＣ５０Ａの周辺セルＣ５０Ｂ～Ｃの構成情報（セルＣ５０Ｂ～Ｃに接続するための接続情報）を含む。セルＣ５０Ａ～Ｃに接続するための接続情報は例えば、セルＣ５０Ａ～Ｃを識別するための識別情報を含む。また、送信する信号は、仮想セルの構成情報（仮想セルに接続するための接続情報）を含む。仮想セルに接続するための接続情報は例えば、仮想セルを識別するための識別情報を含む。仮想セルを識別するための識別情報は例えば、仮想セルを形成する複数のセルをそれぞれ識別するための複数のセル識別情報を含む。具体的には仮想セルを識別するための識別情報は例えば、セル識別情報としては例えば、仮想セルを形成する複数のセルをそれぞれ識別するためのＰＣＩ(Physical Cell ID)の組合せ（リスト）により示される。また、仮想セルに接続するための接続情報は例えば、仮想セルに接続するための接続要求を送信するための無線リソースの割当てや、仮想セルに接続するための接続要求の構成情報や、仮想セルへ接続するか否かを判定するための判定条件を含む。 The reception antenna 71 receives a radio signal and outputs it to the reception RF unit 72. The reception antenna 71 includes, for example, a plurality of antennas. The reception antenna 71 may be configured to be shared with the transmission antenna 85 and switched between transmission and reception by a transmission / reception switching unit or the like. The reception antenna 71 receives, for example, an uplink signal (data signal or control signal) transmitted on an uplink data channel or control channel. Examples of the received signal include a PCH signal for calling the wireless terminal 70A when a call arrives at the wireless terminal 70A, and a response signal to the RACH signal from the wireless terminal 70A. Further, examples of the received signal include a signal indicating the reception level at the radio stations 50A to 50C, and a control signal for controlling uplink transmission power (for example, downlink transmission power information, TPC command, etc.). . The received signal includes, for example, a reference signal for each wireless terminal used for channel estimation and demodulation, and configuration information indicating a wireless resource prepared for reference signal transmission. The signal to be transmitted includes configuration information of the cell C50A (connection information for connecting to the cell C50A) and configuration information of the peripheral cells C50B to C of the cell C50A (connection information for connecting to the cells C50B to C). Including. The connection information for connecting to the cells C50A-C includes, for example, identification information for identifying the cells C50A-C. The signal to be transmitted includes virtual cell configuration information (connection information for connecting to the virtual cell). The connection information for connecting to the virtual cell includes, for example, identification information for identifying the virtual cell. The identification information for identifying the virtual cell includes, for example, a plurality of cell identification information for identifying each of the plurality of cells forming the virtual cell. Specifically, identification information for identifying a virtual cell is indicated by, for example, a combination (list) of PCI (Physical Cell ID) for identifying each of a plurality of cells forming the virtual cell. It is. The connection information for connecting to the virtual cell includes, for example, radio resource allocation for transmitting a connection request for connecting to the virtual cell, connection request configuration information for connecting to the virtual cell, virtual cell The determination condition for determining whether to connect to is included.
　制御信号としては例えば、接続無線局５０Ａから個別制御チャネル上で伝送されるＬ１／Ｌ２シグナリングや、接続無線局５０Ａから共有チャネル上で伝送されるＲＲＣシグナリングが挙げられる。また、制御信号としては例えば、ＭＩＢやＳＩＢに格納されて、報知チャネル又は報知チャネルで指定される共有チャネル上で伝送されるシステム情報が挙げられる。 Examples of the control signal include L1 / L2 signaling transmitted on the dedicated control channel from the connection radio station 50A and RRC signaling transmitted on the shared channel from the connection radio station 50A. The control signal includes, for example, system information stored in MIB or SIB and transmitted on a broadcast channel or a shared channel designated by the broadcast channel.
　受信ＲＦ部７２は、受信信号にＡ／Ｄ変換等の処理を行う。ＦＦＴ部７３は、デジタル信号にＦＦＴ処理を行う。物理チャネル分離部７４は、ＦＦＴ処理された信号から、各チャネルの信号を分離する。物理チャネル分離部７４は例えば、受信されたＯＦＤＭ（Orthogonal Frequency Division Multiplexing）信号からサブキャリア信号を取得する。信号復調部７５は、予め通知されるあるいは格納される制御情報や、復調のための無線端末個別の参照信号に基づいて、分離された各チャネルの信号の復調処理を行う。チャネル推定部７６は、予め通知される或いは格納される制御情報や、受信した無線端末個別の参照信号に基づいて、チャネルの伝搬状態を示すチャネル推定値を取得する。復調処理された信号はチャネル推定値に基づいて復号処理される。復号処理されて取得されたユーザデータや制御情報は、通信制御部７８に出力される。また、データ信号の復号結果として、ＡＣＫ／ＮＡＣＫが通信制御部７８に出力される。 The reception RF unit 72 performs processing such as A / D conversion on the received signal. The FFT unit 73 performs FFT processing on the digital signal. The physical channel separation unit 74 separates each channel signal from the FFT-processed signal. For example, the physical channel separation unit 74 obtains a subcarrier signal from a received OFDM (Orthogonal Frequency Division Multiplexing) signal. The signal demodulator 75 demodulates the signal of each separated channel based on control information notified or stored in advance or a reference signal specific to each radio terminal for demodulation. The channel estimation unit 76 acquires a channel estimation value indicating a channel propagation state based on control information notified or stored in advance or the received reference signal for each wireless terminal. The demodulated signal is decoded based on the channel estimation value. The user data and control information acquired through the decryption process are output to the communication control unit 78. Further, ACK / NACK is output to the communication control unit 78 as a decoding result of the data signal.
　受信レベル測定部７７は、受信した信号から受信レベル（下り受信電力や下り受信品質）を測定する。受信レベル受信レベルとしては例えば、ＲＳＲＰ、ＲＳＲＱ、ＳＩＲ、ＳＩＮＲ等が挙げられる。使用される信号は例えばセル固有の参照信号を含む。 The reception level measuring unit 77 measures the reception level (downlink reception power and downlink reception quality) from the received signal. Examples of reception levels include RSRP, RSRQ, SIR, SINR, and the like. The signals used include, for example, cell-specific reference signals.
　通信制御部７８は、無線局５０Ａ～Ｃとのアクセス管理や、信号を送信する送信電力の制御等の通信制御を行う。送信電力の制御は例えば、通信ポイントとの間の伝搬ロス（パスロス）を補償するオープンループ制御や、適応変調制御や、ＴＰＣコマンドによるクローズドループ制御によって行われる。また、通信制御は例えば、ＣｏＭＰ通信のための処理や、キャリアアグリゲーションのための処理や、ハンドオーバ（Inter-Cell, Inter-Frequency, Inter-Rat等）のための処理を含む。 The communication control unit 78 performs communication control such as access management with the radio stations 50A to 50C and control of transmission power for transmitting signals. The transmission power is controlled by, for example, open loop control that compensates for propagation loss (path loss) between communication points, adaptive modulation control, and closed loop control using a TPC command. The communication control includes, for example, processing for CoMP communication, processing for carrier aggregation, and processing for handover (Inter-Cell, Inter-Frequency, Inter-Rat, etc.).
　上位レイヤデータ処理部７９は、復号処理されたデータ信号のリオーダリング処理等を行い、下りユーザデータを取得する。また、上位レイヤデータ処理部７９は、上りユーザデータや、送信する制御情報を処理して、送信パケットを生成する。 The upper layer data processing unit 79 performs a reordering process on the decoded data signal and acquires the downlink user data. Further, the upper layer data processing unit 79 processes uplink user data and control information to be transmitted, and generates a transmission packet.
　信号生成部８０は、送信パケットを符号化・変調して、上り送信電力情報に基づいて振幅調整し、物理チャネル多重部８２に出力する。参照信号生成部８１は、上り参照信号を生成して物理チャネル多重部８２に出力する。 The signal generation unit 80 encodes and modulates the transmission packet, adjusts the amplitude based on the uplink transmission power information, and outputs it to the physical channel multiplexing unit 82. The reference signal generation unit 81 generates an uplink reference signal and outputs it to the physical channel multiplexing unit 82.
　物理チャネル多重部８２は、符号化・変調された送信パケットや参照信号を物理チャネルの無線リソースに割当てる。ＩＦＦＴ部８３は、多重後の信号にＩＦＦＴ処理を行う。送信ＲＦ部８４は、ＩＦＦＴ処理後の信号に、Ｄ／Ａ変換や、歪補償処理や、増幅処理等を行って、送信アンテナ８５に出力する。 The physical channel multiplexing unit 82 assigns the encoded and modulated transmission packet and reference signal to the physical channel radio resource. The IFFT unit 83 performs IFFT processing on the multiplexed signal. The transmission RF unit 84 performs D / A conversion, distortion compensation processing, amplification processing, and the like on the signal after IFFT processing, and outputs the result to the transmission antenna 85.
　送信アンテナ８５は、送信ＲＦ部８４から入力される無線信号を送信する。なお、送信アンテナ８５は例えば、複数のアンテナを含む。送信アンテナ８５は、例えば上りのデータチャネルや制御チャネル上を伝送される上り信号（データ信号や制御信号）を送信する。送信される信号は例えば、接続確立のためのＲＡＣＨ信号や、無線端末７０Ａでの受信レベルを示す信号や、チャネル推定や復調のための参照信号を含む。 The transmission antenna 85 transmits a radio signal input from the transmission RF unit 84. Note that the transmission antenna 85 includes, for example, a plurality of antennas. The transmission antenna 85 transmits, for example, an uplink signal (data signal or control signal) transmitted on an uplink data channel or control channel. The transmitted signal includes, for example, a RACH signal for establishing a connection, a signal indicating a reception level at the radio terminal 70A, and a reference signal for channel estimation and demodulation.
　以下、通信制御部７８の処理について詳述する。 Hereinafter, the processing of the communication control unit 78 will be described in detail.
　通信制御部７８は、仮想セルに接続するか否かを決定する。通信制御部７８は例えば、仮想セルに接続するための接続情報と、仮想セルを形成する複数の無線局との間の通信状態を示す情報とに基づいて、仮想セルに接続するか否かを決定する。詳細には例えば、通信制御部７８は、仮想セルを識別するための識別情報を用いて、仮想セルを形成する複数の無線局との間の通信状態を示す情報を取得し、所定の判定条件を用いて、仮想セルに接続するか否かを判定する。そして通信制御部７８は、仮想セルに接続する場合、仮想セルに接続するための接続要求を送信し、応答信号を受信して、接続確立のための手順を行い、仮想セルとの接続を確立する。 The communication control unit 78 determines whether or not to connect to the virtual cell. For example, the communication control unit 78 determines whether to connect to the virtual cell based on the connection information for connecting to the virtual cell and the information indicating the communication state between the plurality of radio stations forming the virtual cell. decide. Specifically, for example, the communication control unit 78 uses the identification information for identifying the virtual cell to acquire information indicating the communication state with a plurality of radio stations forming the virtual cell, and the predetermined determination condition Is used to determine whether or not to connect to the virtual cell. Then, when connecting to the virtual cell, the communication control unit 78 transmits a connection request for connecting to the virtual cell, receives a response signal, performs a procedure for establishing the connection, and establishes a connection with the virtual cell. To do.
　なお、第２実施形態に係る無線通信システムにおける無線局５０Ａのハードウェア構成は、図４の無線局１０Ａのハードウェア構成と同様である。無線局５０Ａの受信アンテナ５１と、受信ＲＦ部５２と、送信ＲＦ部６４と、送信アンテナ６５とは、例えばアンテナおよびＲＦ回路により実現される。また、無線局５０ＡのＦＦＴ部５３と、物理チャネル分離部５４と、信号復調部５５と、チャネル推定部５６と、受信レベル測定部５７と、通信制御部５８と、上位レイヤデータ処理部５９と、信号生成部６０と、参照信号生成部６１と、物理チャネル多重部６２と、ＩＦＦＴ部６３とは、例えばＤＳＰ等の集積回路あるいはＣＰＵ等の集積回路により実現される。 Note that the hardware configuration of the radio station 50A in the radio communication system according to the second embodiment is the same as the hardware configuration of the radio station 10A of FIG. The reception antenna 51, the reception RF unit 52, the transmission RF unit 64, and the transmission antenna 65 of the radio station 50A are realized by, for example, an antenna and an RF circuit. Also, the FFT unit 53, the physical channel separation unit 54, the signal demodulation unit 55, the channel estimation unit 56, the reception level measurement unit 57, the communication control unit 58, and the upper layer data processing unit 59 of the radio station 50A The signal generation unit 60, the reference signal generation unit 61, the physical channel multiplexing unit 62, and the IFFT unit 63 are realized by an integrated circuit such as a DSP or an integrated circuit such as a CPU.
　また、第２実施形態に係る無線通信システムにおける無線端末７０Ａのハードウェア構成は、図５の無線端末２０のハードウェア構成と同様である。無線端末７０Ａの受信アンテナ７１と、受信ＲＦ部７２と、送信ＲＦ部８４と、送信アンテナ８５とは、例えばアンテナおよびＲＦ回路により実現される。無線端末７０ＡのＦＦＴ部７３と、物理チャネル分離部７４と、信号復調部７５と、チャネル推定部７６と、受信レベル測定部７７と、通信制御部７８と、上位レイヤデータ処理部７９と、信号生成部８０と、参照信号生成部８１と、物理チャネル多重部８２と、ＩＦＦＴ部８３とは、例えばＣＰＵ等の集積回路により実現される。 Further, the hardware configuration of the wireless terminal 70A in the wireless communication system according to the second embodiment is the same as the hardware configuration of the wireless terminal 20 of FIG. The reception antenna 71, the reception RF unit 72, the transmission RF unit 84, and the transmission antenna 85 of the wireless terminal 70A are realized by, for example, an antenna and an RF circuit. An FFT unit 73, a physical channel separation unit 74, a signal demodulation unit 75, a channel estimation unit 76, a reception level measurement unit 77, a communication control unit 78, an upper layer data processing unit 79, and a signal of the radio terminal 70A The generation unit 80, the reference signal generation unit 81, the physical channel multiplexing unit 82, and the IFFT unit 83 are realized by an integrated circuit such as a CPU, for example.
　次に、第２実施形態に係る無線通信システム１Ａの動作を、図１１～１７を参照して説明する。 Next, the operation of the wireless communication system 1A according to the second embodiment will be described with reference to FIGS.
　まず前提として、無線通信システム１Ａでは、上述のように、無線局１０Ａ～Ｃが、通信態様として、ＣｏＭＰ通信が可能に設けられている。なお、無線局１０Ａ～Ｃは異種の通信方式を使用してもよい。また、無線局１０Ａ～Ｃはキャリアアグリゲーション可能な無線局としてもよい。 First, as a premise, in the radio communication system 1A, as described above, the radio stations 10A to 10C are provided as a communication mode so that CoMP communication is possible. The radio stations 10A to 10C may use different communication methods. The radio stations 10A to 10C may be radio stations capable of carrier aggregation.
　以下の説明では、無線端末ＵＥ＃２の接続確立動作について説明する。無線端末ＵＥ＃２は、無線局５０Ａ，Ｂが形成するセルＣ５０Ａ，Ｂに存在する。 In the following description, a connection establishment operation of the radio terminal UE # 2 will be described. The radio terminal UE # 2 exists in the cells C50A and B formed by the radio stations 50A and B.
　ここで、比較例として、既存の無線通信システムにおける無線端末ＵＥと無線局ｅＮＢ＃１～３との間の接続確立動作について図１１、１２を参照して説明する。無線端末ＵＥと無線局ｅＮＢ１＃１～３との配置は、無線端末ＵＥ＃２と無線局５０Ａ～Ｃとの配置と同様である。 Here, as a comparative example, a connection establishment operation between the radio terminal UE and the radio stations eNB # 1 to 3 in the existing radio communication system will be described with reference to FIGS. The arrangement of the radio terminal UE and the radio stations eNB1 # 1 to 3 is the same as the arrangement of the radio terminal UE # 2 and the radio stations 50A to 50C.
　図１１に示すように、無線局ｅＮＢ＃１～２は、報知チャネルＢＣＨ、共通制御チャネルCommon ＣＣＨの信号を送信する（Ｓ２１）。このとき、報知チャネルＢＣＨ、共通制御チャネルCommon ＣＣＨの信号は、無線局ｅＮＢ＃３からも送信されるが、無線端末ＵＥは受信できず、無線局ｅＮＢ＃１～２からの信号が受信可能である。また、無線局ｅＮＢ＃１からの信号の受信レベルは、無線局ｅＮＢ＃２からの信号の受信レベルよりも高い。Ｓ２１で、無線端末ＵＥは、無線局ｅＮＢ＃１にＲＡＣＨを送信するための無線リソースエレメントを取得する。 As shown in FIG. 11, the radio stations eNB # 1-2 transmit signals of the broadcast channel BCH and the common control channel Common CCH (S21). At this time, the signals of the broadcast channel BCH and the common control channel Common さ れ る CCH are also transmitted from the radio station eNB # 3, but cannot be received by the radio terminal UE and can receive signals from the radio stations eNB # 1-2. is there. Further, the reception level of the signal from the radio station eNB # 1 is higher than the reception level of the signal from the radio station eNB # 2. In S21, the radio terminal UE acquires a radio resource element for transmitting the RACH to the radio station eNB # 1.
　次に、無線端末ＵＥは、無線局ｅＮＢ＃１にＲＡＣＨを送信する（Ｓ２２）。図１２にＲＡＣＨリソースを例示する。図１２において、横軸は周波数（ｆ）、縦軸は時間（ｔ）を示す。図１２の点描が付された無線リソースエレメントは、無線局ｅＮＢ＃１に割当てられたＲＡＣＨを送信するための無線リソースエレメントの例を示す。そして、無線端末ＵＥは無線局ｅＮＢ＃１との間で信号をやり取りして、接続を確立（RRC Connected）する（Ｓ２３）。このように、既存の無線通信システムでは、無線端末ＵＥは、まず１つの無線局との間で接続を確立する。 Next, the radio terminal UE transmits RACH to the radio station eNB # 1 (S22). FIG. 12 illustrates RACH resources. In FIG. 12, the horizontal axis represents frequency (f) and the vertical axis represents time (t). The radio | wireless resource element to which stippling of FIG. 12 was attached | subjected shows the example of the radio | wireless resource element for transmitting RACH allocated to radio station eNB # 1. Then, the radio terminal UE exchanges signals with the radio station eNB # 1 to establish a connection (RRC Connected) (S23). Thus, in the existing radio communication system, the radio terminal UE first establishes a connection with one radio station.
　次に、無線端末ＵＥは、無線局ｅＮＢ＃１からＲＲＣ信号（RRC Signaling）を受信する（Ｓ２４）。次に、無線端末ＵＥは、ＲＲＣ信号による制御情報を用いて、無線局ｅＮＢ＃１～２からそれぞれＣＳＩ－ＲＳを受信する（Ｓ２５）。次に、無線端末ＵＥは、ＣＳＩ－ＲＳへの応答（CSI Feedback）を送信する。具体的には例えば無線端末ＵＥは、ＣＳＩ－ＲＳにより測定した受信レベルを無線局ｅＮＢ＃１に送信して協調連携の処理を実行させるか、あるいは測定した受信レベルに基づいて協調連携の要求を無線局ｅＮＢ＃１に送信する（Ｓ２６）。 Next, the radio terminal UE receives an RRC signal (RRC Signaling) from the radio station eNB # 1 (S24). Next, the radio terminal UE receives CSI-RSs from the radio stations eNB # 1-2 using the control information based on the RRC signal (S25). Next, the radio terminal UE transmits a response (CSI Feedback) to the CSI-RS. Specifically, for example, the radio terminal UE transmits the reception level measured by the CSI-RS to the radio station eNB # 1 to execute the process of cooperative cooperation, or requests the cooperation cooperation based on the measured reception level. It transmits to radio station eNB # 1 (S26).
　これに対して、図１３は、無線通信システム１Ａにおける無線端末ＵＥ＃２と無線局５０Ａ～Ｃとの間の接続確立動作のシーケンス図である。 On the other hand, FIG. 13 is a sequence diagram of a connection establishment operation between the radio terminal UE # 2 and the radio stations 50A to 50C in the radio communication system 1A.
　図１３に示すように、無線局５０Ａは、仮想セルの構成情報を設定（Virtual Cell Information Set）し、無線局５０Ｂ～Ｃに通知する（Ｓ４１）。仮想セルの構成情報は例えば、仮想セルを識別するための識別情報や、無線端末が仮想セルに接続要求するか否か判定するための判定条件や、仮想セルに接続するための接続要求を送受信する無線リソースエレメントの配置を含む。図１４に、仮想セルの構成情報を例示する。図１４の例では、仮想セルＶＣ＃Ａ～Ｂが設定される。仮想セルＶＣ＃Ａ（ＩＤ＝Ａ）の構成情報は、仮想セルＶＣ＃Ａを形成する無線局５０Ａ，Ｂのそれぞれの識別情報「ＰＣＩ＝１，２」、判定条件は「RX Power(RSRP)がxx dBm以上、± w dB以内」、ＲＡＣＨリソース「ａ」を含む。仮想セルＶＣ＃Ｂ（ＩＤ＝Ｂ）の構成情報は、仮想セルＶＣ＃Ｂを形成する無線局５０Ｂ，Ｃのそれぞれの識別情報「ＰＣＩ＝２，３」、判定条件は「RX Power(RSRP)がyy dBm以上、± z dB以内」、ＲＡＣＨリソース「ｂ」を含む。図１５にＲＡＣＨリソースを例示する。図１５において、横軸は周波数（ｆ）、縦軸は時間（ｔ）を示す。図１５の例では、図１２に例示したＲＡＣＨリソースのうち、斜線を付した部分がＶＣ＃ＡのＲＡＣＨリソース（ａ）、格子を付した部分がＶＣ＃Ｂ用のＲＡＣＨリソース（ｂ）に設定される。 As shown in FIG. 13, the radio station 50A sets virtual cell configuration information (Virtual Cell Information Set) and notifies the radio stations 50B to 50C (S41). The virtual cell configuration information includes, for example, identification information for identifying the virtual cell, determination conditions for determining whether or not the wireless terminal requests connection to the virtual cell, and connection requests for connection to the virtual cell. Including arrangement of radio resource elements to be performed. FIG. 14 illustrates the configuration information of the virtual cell. In the example of FIG. 14, virtual cells VC # A-B are set. The configuration information of the virtual cell VC # A (ID = A) is identification information “PCI = 1, 2” of each of the radio stations 50A, B forming the virtual cell VC # A, and the determination condition is “RX Power (RSRP)” Is xx dBm or more and within ± w dB ”, and the RACH resource“ a ”is included. The configuration information of the virtual cell VC # B (ID = B) is the identification information “PCI = 2, 3” of each of the radio stations 50B, C forming the virtual cell VC # B, and the determination condition is “RX Power (RSRP)” Includes yy dBm or more and within ± z dB ", and the RACH resource" b ". FIG. 15 illustrates a RACH resource. In FIG. 15, the horizontal axis represents frequency (f) and the vertical axis represents time (t). In the example of FIG. 15, among the RACH resources illustrated in FIG. 12, the hatched part is set as the RACH resource (a) for VC # A, and the hatched part is set as the RACH resource (b) for VC # B. Is done.
　次に、無線局５０Ａ～Ｂは、仮想セルＶＣ＃Ａ，Ｂの構成情報を送信する（Ｓ４２）。仮想セルＶＣ＃Ａ，Ｂは、ＢＣＨあるいはCommon ＣＣＨとして無線局５０Ａ～Ｂからそれぞれ報知される。 Next, the radio stations 50A to 50B transmit the configuration information of the virtual cells VC # A and B (S42). The virtual cells VC # A and B are broadcast from the radio stations 50A to 50B as BCH or Common CCH, respectively.
　次に、無線端末ＵＥ＃２は、無線局５０Ａ～Ｂとの同期を取り、無線局５０Ａ～Ｂから受信したＢＣＨあるいはCommon ＣＣＨから、仮想セルＶＣ＃Ａ，Ｂの構成情報を取得する（Ｓ４３）。無線端末ＵＥ＃２は、無線局５０Ａ～Ｂから送信される同期チャネルＳＣＨを受信して無線局５０Ａ～Ｂとの同期を取る。 Next, the radio terminal UE # 2 synchronizes with the radio stations 50A to 50B, and acquires the configuration information of the virtual cells VC # A and B from the BCH or Common CCH received from the radio stations 50A to 50B (S43). ). The radio terminal UE # 2 receives the synchronization channel SCH transmitted from the radio stations 50A to 50B and synchronizes with the radio stations 50A to 50B.
　そして、無線端末ＵＥ＃２は、仮想セルＶＣ＃Ａとの接続を決定する。具体的には無線端末ＵＥ＃２は、仮想セルＶＣ＃Ａを形成する無線局５０Ａ～Ｂからの信号を受信し、受信レベルを測定する。そして、測定した受信レベルと、判定条件とにより、仮想セルＶＣ＃Ａに接続要求するか否か決定する。図１６に、仮想セルＶＣ＃Ａを例示する。また、図１７に、仮想セルＶＣ＃Ａの判定条件の例を示す。図１７において、縦軸は受信レベル（ｐ）を示し、横方向は左から順に、無線端末ＵＥ＃１，ＵＥ＃２，ＵＥ＃３を示す。また、各無線端末ＵＥ＃１～３の受信レベルについて、左側の斜線が付された部分は無線局５０Ａからの受信レベルを示し、右側の点描が付された部分は無線局５０Ｂからの受信レベルを示す。例えば、無線局５０Ａ～Ｂからの受信レベルが所定範囲α内にあり、かつ無線局５０Ａからの受信レベルと無線局５０Ｂからの受信レベルとの差が所定範囲β内にある場合に、仮想セルＶＣ＃Ａに接続要求すると判定される。このように、無線局５０Ａと無線局５０Ｂとの協調連携により通信性能が向上すると想定される場合に、仮想セルＶＣ＃Ａに接続要求すると判定される。なお例えば、無線端末ＵＥ＃１のように、仮想セルＶＣ＃Ａに接続要求するための判定条件を満たさず、セルＣ５０Ａに接続要求するための判定条件を満たす場合、セルＣ５０Ａへの接続が決定される。また例えば、無線端末ＵＥ＃３のように、仮想セルＶＣ＃Ａに接続要求するための判定条件を満たさず、セルＣ５０Ｂに接続要求するための判定条件を満たす場合、セルＣ５０Ｂへの接続が決定される。 Then, the radio terminal UE # 2 determines connection with the virtual cell VC # A. Specifically, the radio terminal UE # 2 receives signals from the radio stations 50A to 50B forming the virtual cell VC # A and measures the reception level. Then, whether to make a connection request to the virtual cell VC # A is determined based on the measured reception level and the determination condition. FIG. 16 illustrates the virtual cell VC # A. FIG. 17 shows an example of determination conditions for the virtual cell VC # A. In FIG. 17, the vertical axis indicates the reception level (p), and the horizontal direction indicates radio terminals UE # 1, UE # 2, UE # 3 in order from the left. Regarding the reception levels of the radio terminals UE # 1 to UE # 3, the left hatched portion indicates the reception level from the radio station 50A, and the right dotted portion indicates the reception level from the radio station 50B. Indicates. For example, when the reception level from the radio stations 50A to 50B is within the predetermined range α and the difference between the reception level from the radio station 50A and the reception level from the radio station 50B is within the predetermined range β, the virtual cell It is determined that a connection request is made to VC # A. Thus, when it is assumed that communication performance is improved by cooperative cooperation between the radio station 50A and the radio station 50B, it is determined that a connection request is made to the virtual cell VC # A. For example, as in the case of the radio terminal UE # 1, when the determination condition for requesting connection to the virtual cell VC # A is not satisfied and the determination condition for requesting connection to the cell C50A is satisfied, connection to the cell C50A is determined. Is done. Further, for example, when the determination condition for requesting connection to the cell C50B is not satisfied and the determination condition for requesting connection to the cell C50B is not satisfied, as in the case of the radio terminal UE # 3, the connection to the cell C50B is determined. Is done.
　図１３に戻り、次に、無線端末ＵＥ＃２は、仮想セルＶＣ＃Ａとの接続要求（Virtual Cell Connection Request）を送信する（Ｓ４４）。具体的には、仮想セルＶＣ＃Ａとの接続要求は、仮想セルＶＣ＃Ａの構成情報に設定された無線リソースエレメントａを使用して送信される。例えば、セルＣ５０Ａ，Ｂへの接続確立のために準備されている無線リソースエレメントの一部が、仮想セルＶＣ＃Ａに割当てられている。そして、無線端末ＵＥ＃２から、この割当てられた無線リソースエレメントで接続要求を送信することで、例えば接続要求を受信した無線局５０Ａは、仮想セルＶＣ＃Ａへの接続要求であることを把握することができる。これにより、セルＣ５０Ａへの接続確立へ移行せずに、仮想セルＶＣ＃Ａとの接続の準備が実行され、協調連携による通信へ移行される。 Referring back to FIG. 13, next, the radio terminal UE # 2 transmits a connection request (Virtual Cell Connection Request) with the virtual cell VC # A (S44). Specifically, the connection request with the virtual cell VC # A is transmitted using the radio resource element a set in the configuration information of the virtual cell VC # A. For example, a part of the radio resource elements prepared for establishing a connection to the cells C50A and B is allocated to the virtual cell VC # A. Then, by transmitting a connection request using the allocated radio resource element from the radio terminal UE # 2, for example, the radio station 50A that has received the connection request grasps that it is a connection request to the virtual cell VC # A. can do. As a result, preparation for connection with the virtual cell VC # A is executed without shifting to the establishment of connection to the cell C50A, and the shift to communication by cooperative cooperation is performed.
　次に、無線局５０Ａ～Ｂは、仮想セルＶＣ＃Ａとの接続要求を受信し、無線端末ＵＥ＃２と仮想セルＶＣ＃Ａとの接続を準備（Virtual Cell Connection Setup）する（Ｓ４５）。具体的には例えば、無線局５０Ａが接続要求を受信し、無線端末ＵＥ＃２との接続確立のための情報を、無線局５０Ａから無線局５０Ｂに通知する。 Next, the radio stations 50A to 50B receive the connection request with the virtual cell VC # A and prepare the connection between the radio terminal UE # 2 and the virtual cell VC # A (Virtual Cell Connection Setup) (S45). Specifically, for example, the radio station 50A receives the connection request, and notifies the radio station 50B of information for establishing a connection with the radio terminal UE # 2.
　そして、無線端末ＵＥ＃２と無線局５０Ａ～Ｂとの間で接続確立（RRC Connected）を実行する（Ｓ４６）。これにより、無線局５０Ａと無線局５０Ｂとの協調連携により通信性能が向上すると想定される場合、例えば無線端末ＵＥ＃２が１つの無線局５０Ａとの初期接続を確立してから協調連携の実施可否を判定して協調連携による通信へ移行する場合に比較して、迅速に協調連携による通信を開始することができる。すなわち、効率良く協調連携への切り替えが行われる。 Then, connection establishment (RRC Connected) is executed between the radio terminal UE # 2 and the radio stations 50A and 50B (S46). Thereby, when it is assumed that the communication performance is improved by the cooperative cooperation between the wireless station 50A and the wireless station 50B, the cooperative cooperation is performed after the wireless terminal UE # 2 establishes the initial connection with the single wireless station 50A, for example. Compared to the case of determining whether or not to shift to communication by cooperative cooperation, communication by cooperative cooperation can be quickly started. That is, switching to cooperative cooperation is performed efficiently.
　以上により、第２実施形態によれば、無線通信システム１Ａにおいて、無線端末ＵＥ＃１～３と無線局５０Ａ～Ｃとの間の通信態様を効率良く切り替えて、通信性能を向上できる。 As described above, according to the second embodiment, in the radio communication system 1A, it is possible to efficiently switch the communication mode between the radio terminals UE # 1 to UE # 3 and the radio stations 50A to 50C and improve the communication performance.
　なお、第２実施形態は、無線端末ＵＥ＃１～３から無線局５０Ａ～Ｂへの初期接続の場合以外に、無線端末ＵＥ＃１～３から無線局５０Ａ～Ｂへの再接続の場合にも適用可能である。 In the second embodiment, in addition to the case of the initial connection from the radio terminals UE # 1 to UE # 3 to the radio stations 50A to 50B, in the case of the reconnection from the radio terminals UE # 1 to 3 to the radio stations 50A to 50B. Is also applicable.
　また、第２実施形態において、例えば無線通信システム１は、セル範囲の異なる無線局が混在するヘテロジニアスネットワークでもよい。例えば、無線局１０Ａ～Ｂの一方がＰＣｅｌｌ（Primary cell）を形成し、無線局１０Ａ～Ｂの他方がＳＣｅｌｌ（Secondary cell）を形成する。ＳＣｅｌｌは、ＰＣｅｌｌよりも機能が制限される場合があるセルである。ＳＣｅｌｌは、比較的規模の大きいセル（Macro Cell）に相当し、Ｐｃｅｌｌは、比較的規模の小さいセル（Small Cell）に相当する。例えば、複数のコンポーネントキャリアを動的に連結するキャリアアグリゲーション動作において、ＰＣｅｌｌはＰＣＣ（Primary component carrier）のサービングセル（接続セル）であり、ＳＣｅｌｌはＳＣＣ（Secondary component carrier）のサービングセル（接続セル）である。例えば、ＰＣＣはハンドオーバによって切替えられるのに対し、ＳＣＣは必要に応じて追加や削除が行われる。 In the second embodiment, for example, the wireless communication system 1 may be a heterogeneous network in which wireless stations having different cell ranges are mixed. For example, one of the radio stations 10A to 10B forms a PCell (Primary cell), and the other of the radio stations 10A to 10B forms an SCell (Secondary cell). The SCell is a cell whose function may be more limited than that of the PCell. SCell corresponds to a relatively large cell (Macro Cell), and Pcell corresponds to a relatively small cell (Small Cell). For example, in a carrier aggregation operation that dynamically links a plurality of component carriers, PCell is a serving cell (connected cell) of PCC (PrimaryPrimcomponent carrier), and SCell is a serving cell (connected cell) of SCC (Secondary component carrier). . For example, PCC is switched by handover, while SCC is added or deleted as necessary.
［第３実施形態］
　次に、第３実施形態に係る無線通信システムについて説明する。 [Third Embodiment]
Next, a radio communication system according to the third embodiment will be described.
　第３実施形態に係る無線通信システムの全体的構成は、図８に示す無線通信システム１Ａと同様である。例えば、無線局５０Ａ～Ｃはそれぞれ、有線接続あるいは無線接続を介してネットワーク装置３と接続され、ネットワーク装置３は有線接続あるいは無線接続を介してネットワーク２に接続される。そして、無線局５０Ａ～Ｃは、ネットワーク装置３及びネットワーク２を介して、データや制御情報を送受信可能に設けられている。 The overall configuration of the wireless communication system according to the third embodiment is the same as that of the wireless communication system 1A shown in FIG. For example, each of the wireless stations 50A to 50C is connected to the network device 3 via a wired connection or a wireless connection, and the network device 3 is connected to the network 2 via a wired connection or a wireless connection. The radio stations 50A to 50C are provided so as to be able to transmit and receive data and control information via the network device 3 and the network 2.
　また、無線局５０Ａ～Ｃはそれぞれ、アンテナを有し、通信ポイントに相当する。無線局５０Ａ～ＣはそれぞれセルＣ５０Ａ～Ｃを形成している。無線局５０Ａ～Ｃは、無線局５０Ａ～Ｃ間で有線接続あるいは無線接続を介して通信を行う。また、無線局５０Ａ～Ｃは、無線端末ＵＥ＃１～３に対してＣｏＭＰ通信が可能である。 Further, each of the radio stations 50A to 50C has an antenna and corresponds to a communication point. Radio stations 50A-C form cells C50A-C, respectively. The radio stations 50A to 50C communicate with each other via a wired connection or a wireless connection. The radio stations 50A to 50C can perform CoMP communication with the radio terminals UE # 1 to UE # 3.
　以下の説明では、無線端末ＵＥ＃１は無線局５０Ａが形成するセルＣ５０Ａに存在し、無線端末ＵＥ＃２は無線局５０Ａ，Ｂが形成するセルＣ５０Ａ，Ｂに存在し、無線端末ＵＥ＃３は無線局５０Ｂが形成するセルＣ５０Ｂに存在する。 In the following description, the radio terminal UE # 1 exists in the cell C50A formed by the radio station 50A, the radio terminal UE # 2 exists in the cells C50A and B formed by the radio stations 50A and B, and the radio terminal UE # 3. Exists in the cell C50B formed by the radio station 50B.
　第３実施形態に係る無線局５０Ａ～Ｃの機能的構成およびハードウェア構成は、第２実施形態の図９の無線局５０Ａと同様である。また、第３実施形態に係る無線端末ＵＥ＃１～ＵＥ＃３の機能的構成およびハードウェア構成は、第２実施形態の図１０の無線端末７０Ａと同様である。 The functional configuration and hardware configuration of the radio stations 50A to 50C according to the third embodiment are the same as those of the radio station 50A of FIG. 9 of the second embodiment. Also, the functional configurations and hardware configurations of the radio terminals UE # 1 to UE # 3 according to the third embodiment are the same as those of the radio terminal 70A of FIG. 10 of the second embodiment.
　次に、第３実施形態における無線通信システムの動作を説明する。図１８は、第３実施形態の無線通信システムの接続確立の動作を説明するためのシーケンス図である。第３実施形態では、第２実施形態に示す接続確立の動作が、ハンドオーバ処理手順に適用される。 Next, the operation of the wireless communication system in the third embodiment will be described. FIG. 18 is a sequence diagram for explaining an operation of establishing a connection in the wireless communication system according to the third embodiment. In the third embodiment, the connection establishment operation shown in the second embodiment is applied to the handover processing procedure.
　まず前提として、無線通信システムでは、上述のように、無線局１０Ａ～Ｃが、ＣｏＭＰ通信可能に設けられている。なお、無線局１０Ａ～Ｃは異種の通信方式を使用してもよい。また、無線局１０Ａ～Ｃはキャリアアグリゲーション可能な無線局としてもよい。 First, as a premise, in the wireless communication system, as described above, the wireless stations 10A to 10C are provided so as to be capable of CoMP communication. The radio stations 10A to 10C may use different communication methods. The radio stations 10A to 10C may be radio stations capable of carrier aggregation.
　以下の説明では、無線端末ＵＥ＃２の接続確立動作について説明する。無線端末ＵＥ＃２は、無線局５０Ａ，Ｂが形成するセルＣ５０Ａ，Ｂに存在する。 In the following description, a connection establishment operation of the radio terminal UE # 2 will be described. The radio terminal UE # 2 exists in the cells C50A and B formed by the radio stations 50A and B.
　図１８に示すように、ハンドオーバ前の状態として、無線端末ＵＥ＃２と無線局５０Ａとの接続確立（RRC Connected）が実行されており（Ｓ６１）、無線端末ＵＥ＃２は無線局５０Ａと接続中である。 As shown in FIG. 18, as a state before the handover, connection establishment (RRCRRConnected) between the radio terminal UE # 2 and the radio station 50A is executed (S61), and the radio terminal UE # 2 is connected to the radio station 50A. It is in.
　また、無線局５０Ａは、無線局５０Ｂとの間で仮想セルの構成情報を設定（Virtual Cell Information Set）する（Ｓ６２）。例えば、無線局５０Ａが仮想セルの構成情報を設定し、無線局５０Ｂ～Ｃに通知する。仮想セルの構成情報は例えば、仮想セルを識別するための識別情報や、無線端末ＵＥ＃１～３が仮想セルに接続要求するか否か判定するための判定条件や、仮想セルに接続するための接続要求を送受信する無線リソースエレメントの配置を含む。 Further, the radio station 50A sets the virtual cell configuration information (Virtual Cell Information Set) with the radio station 50B (S62). For example, the radio station 50A sets the virtual cell configuration information and notifies the radio stations 50B to 50C. The configuration information of the virtual cell includes, for example, identification information for identifying the virtual cell, determination conditions for determining whether or not the radio terminals UE # 1 to UE # 3 request connection to the virtual cell, and connection to the virtual cell Including an arrangement of radio resource elements that transmit and receive a connection request.
　また、無線局５０Ａ～Ｂは、ＢＣＨ、Common ＣＣＨを送信する（Ｓ６３）。無線端末ＵＥ＃２は、接続中の無線局５０Ａ受信したＢＣＨあるいはCommon ＣＣＨ信号から、制御情報を取得する。取得する制御情報は、無線局５０Ａからの参照信号を受信するための情報や、周辺無線局５０Ｂからの参照信号を受信するための情報や、ハンドオーバを実行するか否かを判定するハンドオーバ判定条件（例えばCell reselection parameters）等を含む。なお、無線端末ＵＥ＃２は、無線局５０Ｂとの同期を取り、無線局５０Ｂから受信した信号から制御情報を取得することも可能である。 Further, the radio stations 50A to 50B transmit BCH and Common CCH (S63). The radio terminal UE # 2 acquires control information from the BCH or Common CCH signal received by the connected radio station 50A. The control information to be acquired includes information for receiving a reference signal from the radio station 50A, information for receiving a reference signal from the peripheral radio station 50B, and a handover determination condition for determining whether or not to execute a handover. (For example, Cell reselection parameters) and the like. Note that the radio terminal UE # 2 can also acquire control information from a signal received from the radio station 50B by synchronizing with the radio station 50B.
　次に、無線端末ＵＥ＃２は、無線局５０Ａ～Ｂから送信される参照信号ＲＳを受信する（Ｓ６４）。 Next, the radio terminal UE # 2 receives the reference signal RS transmitted from the radio stations 50A to 50B (S64).
　そして、無線端末ＵＥ＃２は、ハンドオーバ処理手順を開始（Handover Setup）する（Ｓ６５）。例えば無線端末ＵＥ＃２は、測定される受信レベルと、ハンドオーバ判定条件とに基づいて、ハンドオーバを実行するか否かを決定する。Ｓ６５では例えば、無線局５０Ａ～Ｂの受信レベルが、無線局５０Ａから無線局５０Ｂへのハンドオーバを実行するハンドオーバ判定条件を満たすものとする。 Then, the radio terminal UE # 2 starts a handover procedure (Handover Setup) (S65). For example, the radio terminal UE # 2 determines whether or not to execute the handover based on the measured reception level and the handover determination condition. In S65, for example, it is assumed that the reception levels of the radio stations 50A to 50B satisfy a handover determination condition for executing a handover from the radio station 50A to the radio station 50B.
　また、無線端末ＵＥ＃２は、接続中の無線局５０Ａ受信したＢＣＨあるいはCommon ＣＣＨ信号から、仮想セルＶＣ＃Ａ，Ｂの構成情報を取得する（Ｓ６６）。そして、無線端末ＵＥ＃２は、仮想セルＶＣ＃Ａとの接続を決定する。具体的には無線端末ＵＥ＃２は、仮想セルＶＣ＃Ａを形成する無線局５０Ａ～Ｂからの受信レベルと、仮想セルＶＣ＃Ａ，Ｂの構成情報に含まれる判定条件とにより、仮想セルＶＣ＃Ａに接続要求するか否か決定する。例えば、無線局５０Ａ～Ｂからの受信レベルが所定範囲内にあり、かつ無線局５０Ａからの受信レベルと無線局５０Ｂからの受信レベルとの差が所定範囲内にある場合に、仮想セルＶＣ＃Ａに接続要求すると判定される。このように、無線局５０Ａと無線局５０Ｂとの協調連携により通信性能が向上すると想定される場合に、仮想セルＶＣ＃Ａに接続要求すると判定される。 Further, the radio terminal UE # 2 acquires the configuration information of the virtual cells VC # A and B from the BCH or Common CCH signal received by the connected radio station 50A (S66). And radio | wireless terminal UE # 2 determines the connection with virtual cell VC # A. Specifically, the radio terminal UE # 2 determines the virtual cell based on the reception level from the radio stations 50A to 50B forming the virtual cell VC # A and the determination condition included in the configuration information of the virtual cells VC # A and B. Determine whether to make a connection request to VC # A. For example, when the reception level from the radio stations 50A to 50B is within a predetermined range and the difference between the reception level from the radio station 50A and the reception level from the radio station 50B is within the predetermined range, the virtual cell VC # It is determined that A is requested to connect. Thus, when it is assumed that communication performance is improved by cooperative cooperation between the radio station 50A and the radio station 50B, it is determined that a connection request is made to the virtual cell VC # A.
　次に、無線端末ＵＥ＃２は、仮想セルＶＣ＃Ａとの接続要求（Virtual Cell Connection Request）を送信する（Ｓ６７）。具体的には、仮想セルＶＣ＃Ａとの接続要求は、仮想セルＶＣ＃Ａの構成情報に設定された無線リソースエレメントａを使用して送信される。例えば、セルＣ５０Ａ，Ｂへの接続確立のために準備されている無線リソースエレメントの一部が、仮想セルＶＣ＃Ａに割当てられている。そして、無線端末ＵＥ＃２から、この割当てられた無線リソースエレメントで接続要求を送信することで、例えば接続要求を受信した無線局５０Ａは、仮想セルＶＣ＃Ａへの接続要求であることを把握することができる。これにより、セルＣ５０Ｂへの接続確立へ移行せずに、仮想セルＶＣ＃Ａとの接続の準備が実行され、協調連携による通信へ移行される。 Next, the radio terminal UE # 2 transmits a connection request (Virtual Cell Connection Request) with the virtual cell VC # A (S67). Specifically, the connection request with the virtual cell VC # A is transmitted using the radio resource element a set in the configuration information of the virtual cell VC # A. For example, a part of the radio resource elements prepared for establishing a connection to the cells C50A and B is allocated to the virtual cell VC # A. Then, by transmitting a connection request using the allocated radio resource element from the radio terminal UE # 2, for example, the radio station 50A that has received the connection request grasps that it is a connection request to the virtual cell VC # A. can do. As a result, preparation for connection with the virtual cell VC # A is executed without shifting to establishment of connection to the cell C50B, and shift to communication by cooperative cooperation.
　次に、無線局５０Ａ～Ｂは、仮想セルＶＣ＃Ａとの接続要求を受信し、無線端末ＵＥ＃２と仮想セルＶＣ＃Ａとの接続を準備（Virtual Cell Connection Setup）する（Ｓ６８）。具体的には例えば、無線局５０Ａが接続要求を受信し、無線端末ＵＥ＃２との接続確立のための情報を無線局５０Ｂに通知する。 Next, the radio stations 50A to 50B receive a connection request with the virtual cell VC # A, and prepare a connection (Virtual 無線 Cell Connection Setup) between the radio terminal UE # 2 and the virtual cell VC # A (S68). Specifically, for example, the radio station 50A receives the connection request and notifies the radio station 50B of information for establishing a connection with the radio terminal UE # 2.
　そして、無線端末ＵＥ＃２と無線局５０Ａ～Ｂとの間で接続が確立（RRC Connected）され、ハンドオーバが完了される（Ｓ６９）。これにより、無線局５０Ａと無線局５０Ｂとの協調連携により通信性能が向上すると想定される場合、例えば無線端末ＵＥ＃２が無線局５０Ｂへの接続を確立してから協調連携の実施可否を判定して協調連携による通信へ移行する場合に比較して、迅速に協調連携による通信を開始することができる。すなわち、効率良く協調連携への切り替えが行われる。 Then, a connection is established between the radio terminal UE # 2 and the radio stations 50A and 50B (RRC Connected), and the handover is completed (S69). Thereby, when communication performance is assumed to be improved by cooperative cooperation between the radio station 50A and the radio station 50B, for example, it is determined whether or not the cooperative cooperation can be performed after the radio terminal UE # 2 establishes a connection to the radio station 50B. Thus, compared with the case of shifting to communication by cooperative cooperation, communication by cooperative cooperation can be started quickly. That is, switching to cooperative cooperation is performed efficiently.
　以上により、第３実施形態によれば、無線通信システムにおいて、無線端末７０Ａ～Ｃと無線局５０Ａ～Ｃとの間の通信態様を効率良く切り替えて、通信性能を向上できる。 As described above, according to the third embodiment, in the wireless communication system, the communication mode between the wireless terminals 70A to 70C and the wireless stations 50A to 50C can be efficiently switched to improve the communication performance.
　第１～第３実施形態の無線通信システムは、例えば、ＬＴＥ－Ａシステムとして実現できる。なお、ＬＴＥ－Ａ以外の通信方式を用いた無線通信システムに適用することも可能である。 The wireless communication system of the first to third embodiments can be realized as an LTE-A system, for example. Note that the present invention can also be applied to a wireless communication system using a communication method other than LTE-A.
　また、第１～第３実施形態において、無線端末は、移動局やユーザ装置（User Equipment, UE）とも称される。また、第１～第３実施形態において、無線端末として、携帯電話機、スマートフォン、ＰＤＡ（Personal　Digital　Assistant）などの携帯端末に適用可能である。また、第１～第３実施形態は、その他、移動中継局など、無線局との間で通信を行う様々な通信機器に対して適用可能である。 In the first to third embodiments, the wireless terminal is also referred to as a mobile station or a user apparatus (User Equipment, mentUE). Further, in the first to third embodiments, the wireless terminal can be applied to a mobile terminal such as a mobile phone, a smartphone, or a PDA (Personal Digital Assistant). In addition, the first to third embodiments can be applied to various communication devices that perform communication with a radio station such as a mobile relay station.
　また、第１～第３実施形態において、無線局は、基地局、無線基地局、アクセスポイントとも称される。また、第１～第３実施形態において、無線局として、マクロ基地局、ピコ基地局、フェムト基地局など、様々な規模の基地局に適用可能である。また、第１～第３実施形態は、その他、中継局など、無線端末との間で通信を行う様々な通信機器に対して適用可能である。 In the first to third embodiments, the radio station is also referred to as a base station, a radio base station, or an access point. In the first to third embodiments, the radio station can be applied to base stations of various scales such as a macro base station, a pico base station, and a femto base station. In addition, the first to third embodiments can be applied to various communication devices that perform communication with a wireless terminal such as a relay station.
　第１～第３実施形態において、例えば無線通信システムは、無線局を基地局として実現できる。この場合、例えば無線局を独立ｅＮｏｄｅＢ（evolved Node B）として実現できる。あるいは、第１～第３実施形態において、例えば無線通信システムは、一部の無線局を基地局の制御ユニット、他部の無線局を基地局の遠隔ユニットとして実現してもよい。この場合、制御ユニットを例えば集中ｅＮｏｄｅＢとし、遠隔ユニットを例えば集中ｅＮｏｄｅＢが有するＲＲＨ（Remote Radio Head）として実現できる。例えば制御ユニットは遠隔ユニットと光ケーブル等の有線接続を介して接続されている。制御ユニットはセルを形成し、遠隔ユニットはそれぞれセルと重なるカバーエリアを形成しており、このカバーエリアを１つのセルとみなして仮想セルが設定される。 In the first to third embodiments, for example, the wireless communication system can be realized with a wireless station as a base station. In this case, for example, the radio station can be realized as an independent eNodeB (evolved Node B). Alternatively, in the first to third embodiments, for example, the radio communication system may be realized by using some radio stations as base station control units and other radio stations as base station remote units. In this case, the control unit can be realized as, for example, a centralized eNodeB and the remote unit can be realized as, for example, an RRH (Remote Radio Radio Head) included in the centralized eNodeB. For example, the control unit is connected to the remote unit via a wired connection such as an optical cable. The control unit forms a cell, and each remote unit forms a cover area that overlaps the cell. A virtual cell is set by regarding this cover area as one cell.
　また、無線局、無線端末の各構成要素の分散・統合の具体的態様は、第１～第３実施形態の態様に限定されず、その全部又は一部を、各種の負荷や使用状況等に応じて、任意の単位で機能的又は物理的に分散・統合して構成することもできる。例えば、メモリを、無線局、無線端末の外部装置としてネットワークやケーブル経由で接続するようにしてもよい。 Further, the specific mode of distribution / integration of each component of the radio station and radio terminal is not limited to the mode of the first to third embodiments, and all or a part thereof can be used for various loads, usage conditions, etc. Accordingly, it may be configured to be functionally or physically distributed / integrated in an arbitrary unit. For example, the memory may be connected via a network or a cable as an external device of a wireless station or a wireless terminal.
　１，１Ａ　無線通信システム
　２　ネットワーク
　３　ネットワーク装置
　１０Ａ～Ｂ，５０Ａ～Ｃ　無線局
　２０，７０Ａ～Ｃ，ＵＥ＃１～＃３　無線端末
　Ｃ１０Ａ～Ｂ，Ｃ５０Ａ～Ｃ　セル
　１１，２１　受信部
　１２，２２　送信部
　１３，２３　制御部
　３１，４１　アンテナ
　３２，４２　ＲＦ回路
　３３，４３　ＣＰＵ
　３４　ＤＳＰ
　３５，４４　メモリ
　３６　ネットワークＩＦ
　５１　受信アンテナ
　５２　受信ＲＦ部
　５３　ＦＦＴ部
　５４　物理チャネル分離部
　５５　信号復調部
　５６　チャネル推定部
　５７　受信レベル測定部
　５８　通信制御部
　５９　上位レイヤデータ処理部
　６０　信号生成部
　６１　参照信号生成部
　６２　物理チャネル多重部
　６３　ＩＦＦＴ部
　６４　送信ＲＦ部
　６５　送信アンテナ
　７１　受信アンテナ
　７２　受信ＲＦ部
　７３　ＦＦＴ部
　７４　物理チャネル分離部
　７５　信号復調部
　７６　チャネル推定部
　７７　受信レベル測定部
　７８　通信制御部
　７９　上位レイヤデータ処理部
　８０　信号生成部
　８１　参照信号生成部
　８２　物理チャネル多重部
　８３　ＩＦＦＴ部
　８４　送信ＲＦ部
　８５　送信アンテナ 1, 1A wireless communication system 2 network 3 network device 10A-B, 50A- C wireless station 20, 70A-C, UE # 1- # 3 wireless terminal C10A-B, C50A- C cell 11, 21 receiving unit 12, 22 Transmitter 13, 23 Control unit 31, 41 Antenna 32, 42 RF circuit 33, 43 CPU
34 DSP
35, 44 Memory 36 Network IF
51 reception antenna 52 reception RF unit 53 FFT unit 54 physical channel separation unit 55 signal demodulation unit 56 channel estimation unit 57 reception level measurement unit 58 communication control unit 59 upper layer data processing unit 60 signal generation unit 61 reference signal generation unit 62 physical channel Multiplexer 63 IFFT unit 64 Transmission RF unit 65 Transmission antenna 71 Reception antenna 72 Reception RF unit 73 FFT unit 74 Physical channel separation unit 75 Signal demodulation unit 76 Channel estimation unit 77 Reception level measurement unit 78 Communication control unit 79 Upper layer data processing unit 80 Signal Generation Unit 81 Reference Signal Generation Unit 82 Physical Channel Multiplexing Unit 83 IFFT Unit 84 Transmission RF Unit 85 Transmission Antenna

Claims (11)

  1. 　無線通信方法であって、
    　無線端末から、複数のセルを１つにまとめた仮想セルに接続するための接続要求を送信し、
    　前記仮想セルを形成する複数の無線局のうちの少なくとも１つの無線局で、前記接続要求を受信し、
    　前記無線端末と前記仮想セルを形成する複数の無線局との接続確立を実行する、
    ことを特徴とする無線通信方法。     A wireless communication method,
    From the wireless terminal, a connection request for connecting to a virtual cell in which a plurality of cells are combined into one is transmitted,
    Receiving the connection request at at least one of the plurality of wireless stations forming the virtual cell;
    Performing connection establishment between the wireless terminal and a plurality of wireless stations forming the virtual cell;
    A wireless communication method.
  2. 　前記複数の無線局のうちの１つの無線局で、前記仮想セルに接続するための接続要求を受信して、前記無線端末との接続確立のための情報を、前記複数の無線局のうちの他の無線局に通知し、前記無線端末と前記仮想セルを形成する複数の無線局との接続確立を実行する、
    ことを特徴とする請求項１に記載の無線通信方法。     One of the plurality of wireless stations receives a connection request for connecting to the virtual cell, and receives information for establishing a connection with the wireless terminal from among the plurality of wireless stations. Notifying other radio stations and executing connection establishment between the radio terminals and a plurality of radio stations forming the virtual cell.
    The wireless communication method according to claim 1.
  3. 　前記仮想セルに接続するための接続情報を、前記複数の無線局のうちの１つの無線局から送信し、
    　前記無線端末で、前記接続情報を受信して、前記接続要求を送信する、
    ことを特徴とする請求項１又は２に記載の無線通信方法。     Connection information for connecting to the virtual cell is transmitted from one of the plurality of wireless stations,
    The wireless terminal receives the connection information and transmits the connection request.
    The wireless communication method according to claim 1 or 2.
  4. 　前記仮想セルに接続するための接続情報は、前記仮想セルを識別するための識別情報を含み、
    　前記仮想セルを識別するための識別情報は、前記仮想セルに含まれる前記複数のセルをそれぞれ識別するための複数のセル識別情報を含む、
    ことを特徴とする請求項３に記載の無線通信方法。     The connection information for connecting to the virtual cell includes identification information for identifying the virtual cell,
    The identification information for identifying the virtual cell includes a plurality of cell identification information for identifying each of the plurality of cells included in the virtual cell.
    The wireless communication method according to claim 3.
  5. 　前記複数の無線局のうち少なくとも１つの無線局から、セル共通の制御情報として、前記仮想セルに接続するための接続情報を報知する、
    ことを特徴とする請求項３又は４に記載の無線通信方法。     Broadcasting connection information for connecting to the virtual cell as control information common to the cell from at least one of the plurality of wireless stations,
    The wireless communication method according to claim 3, wherein the wireless communication method is a wireless communication method.
  6. 　前記無線端末で、前記仮想セルに接続するための接続情報と、前記仮想セルを形成する複数の無線局との間の通信状態を示す情報とに基づいて、前記仮想セルに接続するか否かを決定する、
    ことを特徴とする請求項３～５のいずれかに記載の無線通信方法。     Whether the wireless terminal connects to the virtual cell based on connection information for connecting to the virtual cell and information indicating communication states between a plurality of wireless stations forming the virtual cell To decide,
    The wireless communication method according to any one of claims 3 to 5, wherein:
  7. 　前記無線端末から、前記仮想セルに接続するための接続要求を、初期接続時のランダムアクセス、再接続時のランダムアクセス、およびハンドオーバ時のランダムアクセスの少なくともいずれかとして送信する、
    ことを特徴とする請求項１～６のいずれかに記載の無線通信方法。     A connection request for connecting to the virtual cell is transmitted from the wireless terminal as at least one of random access at the time of initial connection, random access at the time of reconnection, and random access at the time of handover,
    The wireless communication method according to any one of claims 1 to 6, wherein:
  8. 　前記無線端末から、ハンドオーバ処理手順において前記仮想セルに接続するための接続要求を送信する、
    ことを特徴とする請求項１～６のいずれかに記載の無線通信方法。     From the wireless terminal, a connection request for connecting to the virtual cell in a handover processing procedure is transmitted.
    The wireless communication method according to any one of claims 1 to 6, wherein:
  9. 　無線端末と無線局とを有する無線通信システムであって、
    　前記無線端末は、複数のセルを１つにまとめた仮想セルに接続するための接続要求を送信し、
    　前記無線局は、前記接続要求を受信し、
    　前記無線端末および無線局は、前記無線端末と、前記無線局を含む前記仮想セルを形成する複数の無線局との接続確立を実行する、
    　ことを特徴とする無線通信システム。     A wireless communication system having a wireless terminal and a wireless station,
    The wireless terminal transmits a connection request for connecting to a virtual cell in which a plurality of cells are combined into one,
    The wireless station receives the connection request;
    The wireless terminal and the wireless station execute connection establishment between the wireless terminal and a plurality of wireless stations forming the virtual cell including the wireless station.
    A wireless communication system.
  10. 　無線局であって、
    　無線端末から、複数のセルを１つにまとめた仮想セルに接続するための接続要求を受信する受信部と、
    　前記無線端末と、当該無線局を含む、前記仮想セルを形成する複数の無線局との接続確立を実行する制御部と、
    　を有することを特徴とする無線局。     A radio station,
    A receiving unit that receives a connection request for connecting to a virtual cell that combines a plurality of cells into one from a wireless terminal;
    A control unit for establishing connection between the wireless terminal and a plurality of wireless stations forming the virtual cell, including the wireless station;
    A wireless station characterized by comprising:
  11. 　無線端末であって、
    　複数のセルを１つにまとめた仮想セルに接続するための接続要求を送信する送信部と、
    　前記接続要求を受信する無線局を含む、前記仮想セルを形成する複数の無線局との接続確立を実行する制御部と、
    　を有することを特徴とする無線端末。     A wireless terminal,
    A transmission unit that transmits a connection request for connecting to a virtual cell in which a plurality of cells are combined into one;
    A control unit that performs connection establishment with a plurality of radio stations forming the virtual cell, including a radio station that receives the connection request;
    A wireless terminal characterized by comprising:
PCT/JP2013/003910 2013-06-21 2013-06-21 Radio communication method, radio communication system, radio station, and radio terminal WO2014203298A1 (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106455006A (en) * 2015-08-13 2017-02-22 中国电信股份有限公司 Method and user terminal for cell selection

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011152347A1 (en) * 2010-06-04 2011-12-08 シャープ株式会社 Communication system and communication method
JP2013502096A (en) * 2009-08-07 2013-01-17 リサーチ イン モーション リミテッド System and method for virtual carrier for multi-carrier and cooperative multi-point network operation
WO2013024574A1 (en) * 2011-08-12 2013-02-21 パナソニック株式会社 Handover control method, wireless communication terminal and wireless communication device
JP2013507064A (en) * 2009-09-30 2013-02-28 クゥアルコム・インコーポレイテッド Scrambling sequence initialization for cooperative multi-point transmission

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013502096A (en) * 2009-08-07 2013-01-17 リサーチ イン モーション リミテッド System and method for virtual carrier for multi-carrier and cooperative multi-point network operation
JP2013507064A (en) * 2009-09-30 2013-02-28 クゥアルコム・インコーポレイテッド Scrambling sequence initialization for cooperative multi-point transmission
WO2011152347A1 (en) * 2010-06-04 2011-12-08 シャープ株式会社 Communication system and communication method
WO2013024574A1 (en) * 2011-08-12 2013-02-21 パナソニック株式会社 Handover control method, wireless communication terminal and wireless communication device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN106455006A (en) * 2015-08-13 2017-02-22 中国电信股份有限公司 Method and user terminal for cell selection
CN106455006B (en) * 2015-08-13 2019-12-03 中国电信股份有限公司 A kind of method and user terminal for cell selection

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