KR20130087308A - Apparatus and method for performing random access in wireless communication system - Google Patents
Apparatus and method for performing random access in wireless communication system Download PDFInfo
- Publication number
- KR20130087308A KR20130087308A KR1020120008557A KR20120008557A KR20130087308A KR 20130087308 A KR20130087308 A KR 20130087308A KR 1020120008557 A KR1020120008557 A KR 1020120008557A KR 20120008557 A KR20120008557 A KR 20120008557A KR 20130087308 A KR20130087308 A KR 20130087308A
- Authority
- KR
- South Korea
- Prior art keywords
- random access
- response message
- serving cell
- access response
- base station
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 119
- 238000004891 communication Methods 0.000 title abstract description 24
- 230000004044 response Effects 0.000 claims abstract description 155
- 230000005540 biological transmission Effects 0.000 claims abstract description 49
- 238000012545 processing Methods 0.000 claims description 18
- 238000004458 analytical method Methods 0.000 claims description 4
- 239000000969 carrier Substances 0.000 description 32
- 230000002776 aggregation Effects 0.000 description 17
- 238000004220 aggregation Methods 0.000 description 17
- 238000013468 resource allocation Methods 0.000 description 17
- 101000741965 Homo sapiens Inactive tyrosine-protein kinase PRAG1 Proteins 0.000 description 13
- 102100038659 Inactive tyrosine-protein kinase PRAG1 Human genes 0.000 description 13
- 230000008569 process Effects 0.000 description 13
- 238000010586 diagram Methods 0.000 description 10
- 230000004913 activation Effects 0.000 description 7
- 230000009849 deactivation Effects 0.000 description 7
- 230000011664 signaling Effects 0.000 description 7
- 102100024342 Contactin-2 Human genes 0.000 description 5
- 101000690440 Solanum lycopersicum Floral homeotic protein AGAMOUS Proteins 0.000 description 5
- 230000008859 change Effects 0.000 description 5
- 238000005070 sampling Methods 0.000 description 5
- 230000001934 delay Effects 0.000 description 3
- 230000000737 periodic effect Effects 0.000 description 3
- 101150096310 SIB1 gene Proteins 0.000 description 2
- 239000000872 buffer Substances 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 2
- 238000007726 management method Methods 0.000 description 2
- 230000000644 propagated effect Effects 0.000 description 2
- 230000001960 triggered effect Effects 0.000 description 2
- 230000000903 blocking effect Effects 0.000 description 1
- 238000004364 calculation method Methods 0.000 description 1
- 238000005315 distribution function Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000000873 masking effect Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000008450 motivation Effects 0.000 description 1
- 230000008521 reorganization Effects 0.000 description 1
- 230000003252 repetitive effect Effects 0.000 description 1
- 238000001228 spectrum Methods 0.000 description 1
- 230000001360 synchronised effect Effects 0.000 description 1
- 238000009482 thermal adhesion granulation Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access
- H04W74/002—Transmission of channel access control information
- H04W74/008—Transmission of channel access control information with additional processing of random access related information at receiving side
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W74/00—Wireless channel access
- H04W74/08—Non-scheduled access, e.g. ALOHA
- H04W74/0833—Random access procedures, e.g. with 4-step access
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Mobile Radio Communication Systems (AREA)
Abstract
The present invention relates to an apparatus and method for performing random access in a wireless communication system.
The present specification provides a downlink control information including a new data indicator for transmitting a random access preamble to a base station on a secondary serving cell, starting a random access window, and indicating new transmission or retransmission of a random access response message. Receiving a mapped physical downlink control channel from the base station on the secondary serving cell, whether the random access response message is received within a section of the random access window, and whether the new data indicator indicates new transmission A method of performing random access by a terminal, including determining whether the random access response message is successfully received through a physical downlink shared channel on the secondary serving cell, based on whether the random access response message is received.
By using parameters of the HARQ procedure that is performed separately from the random access procedure to determine the success of the random access response message, it becomes possible to implement the random access procedure using the unique identifier of the terminal.
Description
The present invention relates to wireless communication, and more particularly, to an apparatus and method for performing random access in a wireless communication system.
In a typical wireless communication system, although a bandwidth between an uplink and a downlink is set to be different from each other, only one carrier is mainly considered. In the 3GPP (3rd Generation Partnership Project) LTE (Long Term Evolution), the number of carriers constituting the uplink and the downlink is 1 based on a single carrier, and the bandwidths of the UL and the DL are generally symmetrical to be. In this single carrier system, random access is performed using one carrier. However, with the recent introduction of multiple carrier systems, random access can be implemented through multiple component carriers.
The multi-carrier system refers to a wireless communication system capable of supporting carrier aggregation. Carrier aggregation is a technique for efficiently using fragmented small bands in order to combine physically non-continuous bands in the frequency domain and to have the same effect as using logically large bands.
In order to access the network, the UE goes through a random access process. The random access process may be divided into a contention based random access procedure and a non-contention based random access procedure. The biggest difference between the contention-based random access process and the non- contention-based random access process is whether a random access preamble is assigned to one UE. In the contention-free random access process, since the terminal uses a dedicated random access preamble designated only to the terminal, contention (or collision) with another terminal does not occur. Here, contention refers to two or more terminals attempting a random access procedure using the same random access preamble through the same resource. In the contention-based random access process, there is a possibility of contention because the terminal uses a randomly selected random access preamble.
The purpose of performing a random access procedure to the network may include an initial access, a handover, a scheduling request, a timing alignment, and the like.
An object of the present invention is to provide an apparatus and method for performing random access in a wireless communication system.
Another technical problem of the present invention is to provide an apparatus and method for receiving a random access response message using a PDCCH received through a terminal specific search space of a secondary serving cell.
Another technical problem of the present invention is to provide an apparatus and method for performing a random access procedure accompanying HARQ.
Another technical problem of the present invention is to provide a method of determining whether a random access response message is successfully received based on a new data indicator and a random access window.
According to an aspect of the present invention, a method of performing random access by a terminal in a multi-component carrier system is provided. The method includes transmitting a random access preamble to a base station on a secondary serving cell, starting a random access window, and a new data indicator indicating new transmission or retransmission of a random access response message. receiving a physical downlink control channel to which downlink control information (DCI) including a new data indicator (NDI) is mapped from the base station on the secondary serving cell, and the random access response message Whether the random access response message is successfully received through the physical downlink common channel on the secondary serving cell based on whether the received data is received within a section of a random access window and whether the new data indicator indicates new transmission. Determining.
According to another aspect of the present invention, a terminal for performing random access in a multi-component carrier system is provided. The terminal receives a physical downlink control channel to which downlink control information (DCI) including a new data indicator (NDI) indicating new transmission or retransmission of a random access response message is mapped from the base station on the secondary serving cell A transmitter for transmitting a random access preamble to the base station on a secondary serving cell, an information analyzer for interpreting whether the new data indicator indicates new transmission, and generating the random access preamble, Starts a random access window (RA window) by transmitting an allocated random access preamble, and determines whether the random access response message is received within a section of the random access window and based on an analysis result of the information analyzer; Random to determine whether the response message is received successfully And a process processing unit.
Since only the UE-specific search space is defined in the secondary serving cell, the random access procedure is overcome. In addition, by using the parameters of the HARQ procedure that proceeds separately from the random access procedure to determine the success of the random access response message, it is possible to implement a random access procedure using a unique identifier of the terminal.
1 shows a wireless communication system to which the present invention is applied.
2 shows an example of a protocol structure for supporting multiple carriers to which the present invention is applied.
3 shows an example of a frame structure for multi-carrier operation to which the present invention is applied.
4 shows a linkage between a downlink component carrier and an uplink component carrier in a multi-carrier system to which the present invention is applied.
5 is a flowchart illustrating a random access procedure according to an embodiment of the present invention.
6 is a block diagram illustrating a structure of a random access response message according to an embodiment of the present invention.
7 is a block diagram illustrating a structure of a random access response message according to another example of the present invention.
8 is an explanatory diagram illustrating a method of determining, by a terminal, a successful reception of a random access response message according to an embodiment of the present invention.
9 is an explanatory diagram illustrating a method of determining, by a terminal, a reception success of a random access response message according to another embodiment of the present invention.
10 is a flowchart illustrating a method of performing a random access procedure by a terminal according to an embodiment of the present invention.
11 is a flowchart illustrating a method of performing a random access procedure by a base station according to an embodiment of the present invention.
12 is a block diagram illustrating a terminal and a base station according to an embodiment of the present invention.
Hereinafter, some embodiments will be described in detail with reference to exemplary drawings. In adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are assigned to the same components as much as possible even though they are shown in different drawings. In the following description of the embodiments of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present disclosure rather unclear.
In addition, the present invention will be described with respect to a wireless communication network. The work performed in the wireless communication network may be performed in a process of controlling a network and transmitting data by a system (e.g., a base station) Work can be done at a terminal connected to the network.
1 shows a wireless communication system to which the present invention is applied.
Referring to FIG. 1, a
A mobile station (MS) 12 may be fixed or mobile and may be a user equipment (UE), a mobile terminal (MT), a user terminal (UT), a subscriber station (SS), a wireless device, (personal digital assistant), a wireless modem, a handheld device, and the like. The
Hereinafter, downlink refers to communication from the
Carrier aggregation (CA) supports a plurality of carriers, also referred to as spectrum aggregation or bandwidth aggregation. Individual unit carriers bound by carrier aggregation are called component carriers (CCs). Each element carrier is defined as the bandwidth and center frequency. Carrier aggregation is introduced to support increased throughput, prevent cost increases due to the introduction of wideband radio frequency (RF) devices, and ensure compatibility with existing systems. For example, if five elementary carriers are allocated as the granularity of a carrier unit having a bandwidth of 20 MHz, it can support a bandwidth of up to 100 MHz.
Carrier aggregation can be divided into contiguous carrier aggregation between successive element carriers in the frequency domain and non-contiguous carrier aggregation between discontinuous element carriers. The number of carriers aggregated between the downlink and the uplink may be set differently. The case where the number of downlink element carriers is equal to the number of uplink element carriers is referred to as symmetric aggregation and the case where the number of downlink element carriers is different is referred to as asymmetric aggregation.
The size (i.e. bandwidth) of the element carriers may be different. For example, if five element carriers are used for a 70 MHz band configuration, then 5 MHz element carrier (carrier # 0) + 20 MHz element carrier (carrier # 1) + 20 MHz element carrier (carrier # 2) + 20 MHz element carrier (carrier # 3) + 5 MHz element carrier (carrier # 4).
Hereinafter, a multi-carrier system refers to a system that supports carrier aggregation. In a multi-carrier system, adjacent carrier aggregation and / or non-adjacent carrier aggregation may be used, and either symmetric aggregation or asymmetric aggregation may be used.
2 shows an example of a protocol structure for supporting multiple carriers to which the present invention is applied.
Referring to FIG. 2, the common medium access control (MAC)
There are several physical control channels used in the
3 shows an example of a frame structure for multi-carrier operation to which the present invention is applied.
Referring to FIG. 3, the frame consists of 10 subframes. The subframe includes a plurality of OFDM symbols. Each carrier may have its own control channel (eg, PDCCH). The multicarriers may or may not be adjacent to each other. The terminal may support one or more carriers according to its capabilities.
The component carrier may be divided into a primary component carrier (PCC) and a secondary component carrier (SCC) according to activation. The major carriers are always active carriers, and the subcarrier carriers are carriers that are activated / deactivated according to specific conditions. Activation means that the transmission or reception of traffic data is performed or is in a ready state. Deactivation means that transmission or reception of traffic data is impossible and measurement or transmission / reception of minimum information is possible. The terminal may use only one major carrier or use one or more sub-carrier with carrier. A terminal may be allocated a primary carrier and / or secondary carrier from a base station.
4 shows a linkage between a downlink component carrier and an uplink component carrier in a multi-carrier system to which the present invention is applied.
Referring to FIG. 4, the downlink component carriers D1, D2, and D3 are aggregated in the downlink, and the uplink component carriers U1, U2, and U3 are aggregated in the uplink. Where Di is the index of the downlink component carrier and Ui is the index of the uplink component carrier (i = 1, 2, 3). At least one downlink element carrier is a dominant carrier and the remainder is a subordinate element carrier. Similarly, at least one uplink component carrier is a dominant carrier and the remainder is a subindent carrier. For example, D1, U1 are the dominant carriers, and D2, U2, D3, U3 are the subelement carriers.
In the FDD system, the downlink component carrier and the uplink component carrier are configured to be 1: 1. For example, D1 is connected to U1, D2 is U2, and D3 is U1 1: 1. The UE establishes a connection between the downlink component carriers and the uplink component carriers through the system information transmitted by the logical channel BCCH or the terminal dedicated RRC message transmitted by the DCCH. Each connection setting may be cell specific or UE specific.
4 illustrates only a 1: 1 connection setup between the downlink component carrier and the uplink component carrier, but it is needless to say that a 1: n or n: 1 connection setup can also be established. The index of the element carrier does not match the order of the element carriers or the position of the frequency band of the corresponding element carrier.
A primary serving cell is a serving cell that provides security input and NAS mobility information in an RRC establishment or re-establishment state. Depending on the capabilities of the terminal, at least one cell may be configured to form a set of serving cells together with a main serving cell, said at least one cell being referred to as a secondary serving cell.
Therefore, the set of serving cells set for one UE may consist of only one main serving cell, or may consist of one main serving cell and at least one secondary serving cell.
The downlink component carrier corresponding to the main serving cell is referred to as a downlink principal carrier (DL PCC), and the uplink component carrier corresponding to the main serving cell is referred to as an uplink principal carrier (UL PCC). In the downlink, the element carrier corresponding to the secondary serving cell is referred to as a downlink sub-element carrier (DL SCC), and in the uplink, an elementary carrier corresponding to the secondary serving cell is referred to as an uplink sub-element carrier (UL SCC) do. Only one DL serving carrier may correspond to one serving cell, and DL CC and UL CC may correspond to each other.
Therefore, the communication between the terminal and the base station in the carrier system is performed through the DL CC or the UL CC, which is equivalent to the communication between the terminal and the base station through the serving cell. For example, in the method of performing random access according to the present invention, a UE transmits a preamble using UL CC is equivalent to transmitting a preamble using a main serving cell or a secondary serving cell. In addition, receiving a downlink information using a DL CC by a UE can be regarded as equivalent to receiving downlink information using a main serving cell or a secondary serving cell.
On the other hand, the main serving cell and the secondary serving cell have the following characteristics.
First, the main serving cell is used for transmission of the PUCCH. On the other hand, the secondary serving cell can not transmit the PUCCH but may transmit some of the information in the PUCCH through the PUSCH.
Second, the main serving cell is always activated, while the secondary serving cell is a carrier that is activated / deactivated according to a specific condition. The specific condition may be when the activation / deactivation MAC CE message of the eNB is received or the deactivation timer in the UE expires.
Third, when the primary serving cell experiences RLF, RRC reconnection is triggered, but when the secondary serving cell experiences RLF, RRC reconnection is not triggered. Radio link failure occurs when downlink performance is maintained below a threshold for more than a certain time, or when the RACH has failed a number of times above the threshold.
Fourth, the main serving cell may be changed by a security key change or a handover procedure accompanied by the RACH procedure. However, in the case of a content resolution message, only a downlink control channel indicating a CR (hereinafter referred to as a 'PDCCH') should be transmitted through the primary serving cell, and the CR information may be transmitted through the primary serving cell or the secondary serving cell. Can be sent through.
Fifth, non-access stratum (NAS) information is received through the main serving cell.
Sixth, the main serving cell always consists of DL PCC and UL PCC in pairs.
Seventh, a different CC may be set as a primary serving cell for each terminal.
Eighth, procedures such as reconfiguration, adding, and removal of the secondary serving cell may be performed by the radio resource control (RRC) layer. In addition to the new secondary serving cell, RRC signaling may be used to transmit the system information of the dedicated secondary serving cell.
Ninth, the main serving cell transmits PDCCH (e.g., downlink allocation information) assigned to a UE-specific search space set for transmitting control information for a specific UE in a region for transmitting control information Or PDCCH (e.g., system information (e.g., uplink information) allocated to a common search space set for transmitting control information to all terminals in the cell or to a plurality of terminals conforming to a specific condition, SI), a random access response (RAR), and transmit power control (TPC). On the other hand, only the UE-specific search space can be set as the serving cell. That is, since the UE can not confirm the common search space through the secondary serving cell, it can not receive the control information transmitted only through the common search space and the data information indicated by the control information.
Among the secondary serving cells, a secondary serving cell in which a common search space (CSS) can be defined may be defined, and the secondary serving cell is referred to as a special secondary serving cell (special SCell). The special secondary serving cell is always configured as a scheduling cell during cross carrier scheduling. In addition, the PUCCH configured in the PCell may be defined for the special secondary serving cell.
The PUCCH for the special secondary serving cell may be fixedly set in the special secondary serving cell configuration or the base station may be allocated (configured) or released by RRC signaling (RRC reconfiguration message) upon reconfiguration for that secondary serving cell have.
The PUCCH for the special-purpose serving cell includes ACK / NACK information or CQI (channel quality information) of the secondary serving cells existing in the sTAG, and as mentioned above, can be configured through RRC signaling by the base station have.
In addition, the base station may configure a special secondary serving cell of one of a plurality of secondary serving cells in the sTAG, or may not configure a special secondary serving cell. The reason for not configuring the special secondary serving cell is because it is determined that CSS and PUCCH need not be set. For example, if the contention-based random access procedure does not need to proceed in any serving cell, or if it is determined that the capacity of the current serving cell's PUCCH is sufficient and the PUCCH for the additional serving cell is not needed .
The technical idea of the present invention regarding the characteristics of the main serving cell and the secondary serving cell is not necessarily limited to the above description, but is merely an example and may include more examples.
In a wireless communication environment, a propagation delay is propagated while a transmitter propagates and propagates in a receiver. Therefore, even if the transmitter and the receiver both know the time at which the radio wave is propagated correctly, the arrival time of the signal to the receiver is influenced by the transmission / reception period distance and the surrounding propagation environment. If the receiver does not know exactly when the signal transmitted by the transmitter is received, it will receive the distorted signal even if it fails to receive or receive the signal.
Therefore, in the wireless communication system, synchronization between the base station and the terminal must be predetermined in order to receive the information signal regardless of the downlink / uplink. Types of synchronization include frame synchronization, information symbol synchronization, and sampling period synchronization. Sampling period synchronization is the most basic motivation to distinguish physical signals.
The downlink synchronization acquisition is performed in the UE based on the signal of the base station. The base station transmits a mutually agreed specific signal for facilitating downlink synchronization acquisition at the terminal. The terminal must be able to accurately identify the time at which a particular signal sent from the base station is transmitted. In case of downlink, since one base station simultaneously transmits the same synchronization signal to a plurality of terminals, each of the terminals can acquire synchronization independently of each other.
In case of uplink, the base station receives signals transmitted from a plurality of terminals. When the distance between each terminal and the base station is different, signals received by each base station have different transmission delay times. When uplink information is transmitted on the basis of the acquired downlink synchronization, Is received at the corresponding base station. In this case, the base station can not acquire synchronization based on any one of the terminals. Therefore, uplink synchronization acquisition requires a procedure different from downlink.
A random access procedure is performed to obtain uplink synchronization, and the terminal acquires uplink synchronization based on a timing alignment value transmitted from the base station during the random access procedure. When uplink synchronization is obtained, the terminal starts a time alignment timer. When the time alignment timer is in operation, the terminal and the base station are in a state of uplink synchronization with each other. If the time alignment timer expires or does not operate, the UE and the base station report that they are not synchronized with each other, and the UE does not perform uplink transmission other than the transmission of the random access preamble.
Meanwhile, in a multi-carrier system, one terminal communicates with a base station via a plurality of element carriers or a plurality of serving cells. If all the signals of the plurality of serving cells set in the UE have the same time delay, the UE can acquire uplink synchronization for all the serving cells with only one time alignment value. On the other hand, if the signals of the plurality of serving cells have different time delays, a different time alignment value is required for each serving cell. That is, multiple timing alignment values are required. If the UE performs random access to each serving cell in order to obtain multi-time alignment values, overhead occurs in the limited uplink resources, and the complexity of the random access may increase. A timing alignment group (TAG) is defined to reduce this overhead and complexity.
The time alignment group is a group including at least one serving cell, and the same time alignment value is applied to the serving cells in the time alignment group. For example, when the first serving cell and the second serving cell belong to the same time alignment group TAG1, the same time alignment value TA 1 is applied to the first serving cell and the second serving cell. On the other hand, when the first serving cell and the second serving cell belong to different time alignment groups TAG1 and TAG2, different time alignment values TA 1 and TA 2 are applied to the first serving cell and the second serving cell, respectively. The time alignment group may include a main serving cell, may include at least one secondary serving cell, and may include a primary serving cell and at least one secondary serving cell.
The time alignment group is determined by the base station, the initial group configuration and group reorganization is transmitted to the terminal through the RRC signaling.
The main serving cell does not change the TAG. In addition, the terminal should be able to support at least two TAG when a multi-time forward value is required. For example, it should be able to support pTAG (primary TAG) including main serving cell and TAG separated by sTAG (secondary TAG) without main serving cell. Here, only one pTAG may exist at any time, and at least one sTAG may exist if a multi-time forward value is required.
The serving base station and the terminal may proceed as follows to obtain and maintain a time advance (TA) value for each time alignment group.
1. The TA value acquisition and maintenance of pTAG always proceed through the main serving cell. In addition, a timing reference as a reference of downlink synchronization for calculating a TA value of pTAG is always a downlink CC in a main serving cell.
2. The RA procedure initialized by the base station must be used to obtain the initial uplink time alignment value for the sTAG.
3. The timing reference for the sTAG is an uplink CC and a system information block 2 (SIB2) linked downlink CC of the secondary serving cell that transmitted the random access preamble in the most recent RA procedure. Here, SIB2 is one of system information blocks transmitted through a broadcasting channel, and the SIB2 information is transmitted from the base station to the terminal through an RRC reconfiguration procedure when configuring the corresponding secondary serving cell. Uplink center frequency information is included in SIB2 and downlink center frequency information is included in SIB1. Therefore, the SIB2 connection setup means a connection setup between the downlink CC configured based on the information in the SIB1 of the secondary serving cell and the uplink CC configured based on the information in the SIB2.
4. Each TAG has one timing reference and one time alignment timer (TAT), and each TAT can be configured with a different timer expiration value. The TAT starts or restarts immediately after acquiring the time alignment value from the serving base station to determine whether the time alignment value obtained and applied by each time alignment group is valid.
5. If the TTAG of the pTAG has expired, the TAT of all TAGs including the pTAG expires. The terminal initializes (flush) HARQ buffers of all serving cells. It also clears the resource allocation configuration for all downlinks and uplinks. For example, if the periodic resource allocation is configured without control information transmitted for resource allocation for downlink / uplink such as PDCCH, such as semi-persistent scheduling (SPS), the SPS configuration is initialized. Also, the configuration of PUCCH and Type 0 (periodic) SRS of all serving cells is released.
6. If the TAT of the sTAG has expired, proceed as follows.
A. Stop SRS transmission on the uplink CC of secondary serving cells in the sTAG.
B. Type 0 (periodic) Unconfigure SRS. Type 1 (aperiodic) SRS configuration is maintained.
C. Maintain configuration information for CSI reports.
D. Flush HARQ buffers for the uplink of secondary serving cells in sTAG.
7. Even if all secondary serving cells in the sTAG are deactivated, the terminal does not stop the TAT of the corresponding sTAG.
8. If the last secondary serving cell in the sTAG is removed, ie no serving cell is configured in the sTAG, the TAT in that sTAG is stopped.
9. The random access procedure for the secondary serving cell may be performed by the base station transmitting the PDCCH order for the activated secondary serving cell. It may proceed in the form of a contention free random access procedure or contention random access procedure.
10. The PDCCH for RAR transmission may be transmitted through a serving cell other than the secondary serving cell that transmitted the random access preamble.
11. The path loss reference of the pTAG may be a main serving cell or a secondary serving cell in the pTAG, and the base station may set differently through RRC signaling for each serving cell in the pTAG.
The path loss reference of the uplink CCs of each serving cell in the sTAG is each an SIB2 connected downlink CC.
5 is a flowchart illustrating a random access procedure according to an embodiment of the present invention. This is a contention free random access procedure.
Referring to FIG. 5, the base station selects one of dedicated random access preambles previously reserved for a non-contention based random access procedure among all available random access preambles, and the index and available time / of the selected random access preamble / The preamble assignment information including the frequency resource information is transmitted to the terminal (S500). The UE needs to be allocated a dedicated random access preamble with no possibility of collision from the base station for a non-contention based random access procedure.
As an example, when the random access procedure is performed during the handover procedure, the UE may obtain a dedicated random access preamble from the handover command message. As another example, when the random access procedure is performed by a request of the base station (PDCCH order), the UE may obtain a dedicated random access preamble through PDCCH, that is, physical layer signaling. In this case, the physical layer signaling is downlink control information (DCI) format 1A and may include fields shown in Table 1 below.
-Flag to identify
If the Format 1A CRC is scrambled by the C-RNTI and the remaining fields are set as follows, Format 1A is used for the random access procedure initiated by the PDCCH order.
-bottom-
Localized / Distributed VRB allocation flag-1 bit. Set to 0
Resource block allocation 
Preamble Index-6 bits
PRACH Mask Index-4 bits
All remaining bits of format 1A for simple scheduling allocation of one PDSCH codeword are set to 0.
Referring to Table 1, the preamble index is an index indicating a preamble selected from among dedicated random access preambles reserved for the contention-free random access procedure, and the PRACH mask index is available time / frequency resource information. The available time / frequency resource information is indicated again according to a frequency division duplex (FDD) system and a time division duplex (TDD) system, as shown in Table 2 below.
Mask index
First PRACH Resource Index in Subframe
First PRACH Resource Index in
First PRACH Resource Index in Subframe
First PRACH Resource Index in Subframe
The terminal transmits the allocated dedicated random access preamble to the base station (S505). The random access preamble may be transmitted through the representative serving cell. The representative serving cell is a serving cell selected to transmit a random access preamble in a time alignment group configured in the terminal. The representative serving cell may be selected for each time alignment group. In addition, the UE may transmit a random access preamble on a representative serving cell in any one time alignment group among a plurality of time alignment groups, or may transmit a random access preamble on each representative serving cell in two or more time alignment groups. . For example, suppose that the time alignment groups configured in the terminal are TAG1 and TAG2, and TAG1 = {first serving cell, second serving cell, third serving cell}, and TAG2 = {fourth serving cell, fifth serving cell}. . If the representative serving cell of TAG1 is the second serving cell and the representative serving cell of TAG2 is the fifth serving cell, the terminal transmits the allocated dedicated random access preamble to the base station through the second serving cell or the fifth serving cell.
The representative serving cell may be called a special SCell, a reference SCell, or a timing reference serving cell. Unlike the above embodiment, if the time alignment group configuration information does not include information related to the representative serving cell, the base station transmits a preamble through a random access procedure indicator such as a PDCCH order (order) and SIB2 connection establishment ( linked) A DL CC is defined as a DL CC as a timing reference, and a serving cell including the timing reference DL CC is defined as a timing reference serving cell.
The random access procedure may proceed after the representative serving cell is activated. In addition, the random access procedure for the secondary serving cell may be initiated by the PDCCH order (order) transmitted by the base station.
If only the time alignment value (hereinafter, the representative time alignment value) regarding the representative serving cell is obtained, the terminal may use the representative time alignment value as the time alignment value of another serving cell. This is because the same time alignment value is applied to the serving cells belonging to the same time alignment group. By blocking unnecessary random access procedures in a specific serving cell, duplication, complexity, and overhead of the random access procedure can be reduced.
The base station may determine which terminal transmits the random access preamble through which serving cell based on the received random access preamble and time / frequency resources. In particular, when the UE proceeds with a random access procedure for the secondary serving cell according to the PDCCH order of the base station, the UE already has a unique identifier of the UE in the main serving cell, for example, a C-RNTI (Cell-Radio Network). Temporary Identifier) is secured. Accordingly, the base station may use the C-RNTI of the terminal as needed, and may transmit downlink information to the terminal using the C-RNTI. For example, the downlink information includes a random access response message that is a response to the reception of the random access preamble.
The base station sets a value of a new data indicator (NDI) (S510). The new data indicator is a parameter used to perform HARQ and indicates whether a transport block (TB) for a terminal is first transmitted or retransmitted. Here, the transport block includes a random access response message. A transport block may be defined as a variable number of bits based on downlink resource allocation in a single subframe. The new data indicator may be transmitted in a subframe period. The new data indicator may correspond to the transport block either 1: 1 or 1: 2 (in case of spatial multiplexing). The new data indicator is, for example, 1 bit, and its value may or may not be toggled every subframe period.
As an example, when the value of the new data indicator is compared with the previous value, the toggle means that the corresponding transport block is new transmission. For example, when the base station transmits the random access response message to the terminal for the first time, the base station sets to toggle the new data indicator corresponding to the random access response message.
As another example, when the value of the new data indicator is not toggled when compared to the previous value, it means that the corresponding transport block is retransmitted in the HARQ process. For example, when the base station retransmits the random access response message to the terminal, the base station sets not to toggle the value of the new data indicator corresponding to the random access response message.
As another example, when a new data indicator corresponding to a transport block is first transmitted to the terminal (that is, there is no previous new data indicator corresponding to the transport block), the terminal transmits the transmission block for the corresponding transport block regardless of the toggle. It is determined that this is a new transmission. For example, when the base station first transmits a random access response message to the terminal, the base station sets the first new data indicator corresponding to the random access response message.
The base station generates a DCI including the new data indicator (S515). DCI including the new data indicator may be defined as shown in the following table.
Resource Block Assignment Field
- 
-For this field 
1 bit indicates the shift of resource allocation span
- 
Modulation and coding scheme /
HARQ process number-3 bits (FDD), 4 bits (TDD)
New data indicator-1 bit
-Repeated version-2 bits
TPC command for scheduled PUCCH-2 bits
A carrier indicator (CI) indicating the index of the component carrier-3 bits
Downlink assignment index (DAI): This field is present for all uplink-downlink configurations in the TDD. -2 bits
Referring to Table 3, DCI is
The terminal adds a cyclic redundancy check (CRC) parity bit to the generated DCI (S520), and scrambles the added CRC as its own C-RNTI (S525). Scrambled may also be called masking. The PDCCH to which the CRC scrambled with DCI and C-RNTI is mapped is called PDCCH scambled with C-RNTI. The specific process of scrambling is as follows. Let the payloads of the PDCCH be a 0 , a 1 , a 2 , ..., a A -1 and the CRC parity bits are p 0 , p 1 , p 2 , ..., p L -1 . As a result of the calculation, the CRC parity bits are converted into the sequences b 0 , b 1 , b 2 ,..., B B −1 , where B = A + L. If k = 0, 1, 2, ...., A-1, c k = b k, and if k = A, A + 1, A + 2, ..., A + 15 c k = (b k + x RNTI , kA )
The base station transmits the scrambled PDCCH and the PDSCH to which the random access response message is mapped to the terminal (S530). The random access response message may be mapped to the PDSCH alone, or may be multiplexed with other data in a single MAC PDU and mapped to the PDSCH. The random access response message is transmitted to the terminal through the PDSCH indicated by the PDCCH scrambled with the C-RNTI of the terminal. The random access response message may be transmitted on the secondary serving cell. The resource used for transmission of the PDSCH to which the random access response message is mapped is indicated by the resource block allocation field in the DCI of Table 3. The random access response message may be transmitted through a scheduling cell for the secondary serving cell.
The common search space is allocated a PDCCH scrambled by random access (RA) -RNTI. Since the common search space is not defined in the secondary serving cell and only the UE-specific search space is defined, the terminal may receive the PDCCH scrambled by the RA-RNTI and the random access response message indicated by the PDCCH on the secondary serving cell. Can't.
Accordingly, in order to receive a random access response message in the secondary serving cell, the terminal has no choice but to use the terminal-specific search space. Since the PDCCH scrambled by the C-RNTI is allocated in the UE-specific search space, the base station indicates the PDSCH for the random access response message as the PDCCH scrambled by the C-RNTI.
The random access response message may include a timing advance command (TAC) field. The base station measures a relative change in the current uplink time relative to the reference time based on the random access preamble received from the terminal, and reflects the measured value in a timing advance command field (TACF). The measured change in the uplink time may be an integer multiple of the sampling time T s , for example 16T s . The time advance command field indicates a time alignment value for equally adjusting the uplink time of all the serving cells in the time alignment group. The time alignment value can be given by a specific index.
Here, the reference time may be determined differently for each downlink and uplink by the base station. For example, the reference time may be the same as the transmission reference point of the downlink signal transmitted by the base station and the reception reference point of the uplink signal expected by the base station. In general, the downlink transmission reference time of each serving cell may vary within 0 μs to 1.3 μs.
The DCI of Table 3 may be transmitted through a lower layer control channel defined as EPDCCH (Extended PDCCH). EPDCCH consists of a resource block (RB) pair. Herein, the RB pair may be defined as an RB for each of two slots constituting one subframe, and may be defined as a pair when each RB is configured as one pair. Here, each RB constituting the RB pair may not be configured with slots having the same time. In addition, it may be composed of RBs existing in the same frequency band or may be composed of RBs existing in different frequency bands.
The terminal determines whether a random access response message (RAR) has been successfully received (S535). The following conditions i) and ii) must be met for successful reception of a random access response message. i) A random access response message will be received during a given RA window period. The receiving of the random access response message may include receiving a PDCCH scrambled with C-RNTI using a C-RNTI in a UE-specific search space of a secondary serving cell, and receiving the PDCCH scrambled with the C-RNTI. Receiving a PDSCH indicated by the step, and confirming that a random access response message including a time alignment value for the terminal exists in the received PDSCH. Receiving the PDCCH scrambled with the C-RNTI, the UE searches for the PDCCH in the UE-specific search space of the secondary serving cell, performs channel decoding, descrambling with the C-RNTI, CRC Removing the parity bit.
ii) The transmission of the random access response message shall be new. The terminal may determine whether the random access response message is new by using the new data indicator. The new data indicator is included in the DCI of the PDCCH scrambled with C-RNTI. If the new data indicator is initially transmitted for the random access response message, or if the value of the new data indicator is toggled compared to the previous value, the terminal considers the random access response message to be new. Otherwise, the terminal assumes that the random access response message has been resent.
For example, if the terminal receives the random access response message within the random access window interval and the random access response message is due to new transmission, the terminal is considered to have successfully received the random access response message. On the other hand, if the terminal does not receive the random access response message within the random access window interval, or if the random access response message is retransmission, the terminal is considered to have failed to receive the random access response message. In this case, the terminal ignores the received random access response message and transmits a new random access preamble to the base station.
Meanwhile, the terminal transmits an ACK / NACK signal indicating the success or failure of decoding of the PDSCH itself to which the random access response message is mapped, to the base station. This is performed separately from the progress of the random access procedure. Since the random access response message is indicated by the PDCCH scrambled with the C-RNTI, and the random access response message itself is also downlink data, the HARQ procedure can be equally applied. Accordingly, the UE transmits an ACK signal when the decoding of the PDSCH to which the random access response message is mapped is successful, and transmits an NACK signal when decoding of the PDSCH to which the random access response message is mapped is failed. Successful decoding of the PDSCH to which the random access response message is mapped is different from successful reception of the random access response message. Successful reception of the random access response message is defined in terms of the success of the random access procedure rather than HARQ, and the conditions of i) and ii) must be satisfied.
When the random access response message is successfully received, the UE checks the time advance command field in the random access response message and adjusts an uplink time for the corresponding secondary serving cell by a time alignment value according to the time advance command (S540). . The uplink time TA adjusted by the time alignment value may be calculated by
Here, N TA is a time alignment value, which is variably controlled by a time advance command of a base station, and N TA offset is a value fixed by a frame structure. T s is the sampling period. In this case, when the time alignment value N TA is positive, it indicates adjusting to advance the uplink time, and when it is negative, it adjusts to delaying the uplink time.
Let N TA be the maximum value. For example, when the TAC field is defined as 11 bits, M may be defined as 2047. Here, the maximum value of the time alignment value defined by K bits is not always fixed to (2 K -1). That is, the maximum value of the time alignment value defined by K bits may be one of 2 K-1 to (2 K- 1) values. For example, the maximum value of the time alignment value defined by 11 bits may be 1282, which is one of values in the range of 1024 to 2047.
On the other hand, the time alignment value (N TA) is currently set N TA value - the new N TA value by value of index from the (N TA old) - is adjusted by (N TA new), the new N TA value is obtained as equation (2) Can be done.
Referring to
Alternatively, the time alignment value N TA may be determined as a difference value with respect to the time alignment value of the TAG included in the main serving cell as shown in
See equation (3) when, N TA - TAG (Sn) is a time alignment value for the primary serving cell (PCell) time-aligned groups, the index value n of not including a, N TA - TAG (p) is a primary serving A time alignment value for a time alignment group including a cell (PCell). T i -n is the T i value for the time alignment group whose index value is n. If the maximum value of the time alignment value is M, it may be defined as (M-1) / 2 instead of the constant value 31. For example, if the TAC field is 11 bits, the maximum value of the time alignment value is 2047. In this case, the constant value 31 may be replaced with the value (2047-1) / 2 = 1023. However, the maximum value of the time alignment value defined by K bits is not always fixed to (2 K -1). That is, the maximum value of the time alignment value defined by K bits may be one of 2 K-1 to 2 K- 1 values. For example, the maximum value of the time alignment value defined by 11 bits may be 1282, which is one of values in the range of 1024 to 2047.
When the UE first receives the time alignment value for the serving cell, since there is no target value to prepare, the time alignment value NTA may be determined as shown in
As another example, when the propagation delay time of the downlink transmission is the same as the propagation delay time of the uplink transmission, the terminal may adjust the uplink time for all serving cells using the propagation delay time of the downlink transmission.
If there is a time advance command and / or a time alignment group index for a plurality of time alignment groups in the random access response message, the UE transmits an uplink time for the serving cell (s) of each time alignment group to the corresponding time advance command. Adjust by time alignment value accordingly.
5 shows a process of adjusting uplink time based on a contention-free random access procedure. However, the technical idea of FIG. 5 may be equally applied to a contention-based random access procedure. According to the contention-based random access procedure, step S500 is not performed. In addition, in step S505, the terminal does not use the dedicated random access preamble. Instead, the UE randomly selects one preamble signature from the random access preamble signature set and transmits a random access preamble according to the selected preamble signature to the base station through the secondary serving cell using the PRACH resource. In addition, when the contention-based random access procedure is followed, the BS may additionally transmit a contention resolution message indicating that the random access is successfully terminated to the UE. This is to inform that random access is successfully terminated because contention-based transmission of random access preambles may collide when contention-based.
6 is a block diagram illustrating a structure of a random access response message according to an embodiment of the present invention.
Referring to FIG. 6, the random access response message may be configured in the format of the
The
MAC control elements 620-1, ..., 620-n are control messages generated by the MAC layer.
The
Each subheader 610-1, 610-2, 610-3, 610-4,..., 610-k includes four fields such as R, R, E, LCID, or R, R, E It can contain six fields: LCID, F, L. Subheaders containing four fields are subheaders corresponding to MAC control elements 620-1, ..., 620-n or
The Logical Channel ID (LCID) field may identify a logical channel corresponding to the MAC SDUs 630-1,..., 630-m, or may include a
For example, the LCID field indicates whether the MAC control elements 620-1, ..., 620-n are MAC control elements for indicating activation / deactivation of the serving cell as shown in Table 4, or contention for contention resolution between terminals. Contention Resolution Identity Identifies whether it is a MAC control element or a MAC control element for time advance commands. The MAC control element for the time forward command is the MAC control element used for time alignment in random access.
Referring to Table 4, if the value of the LCID field is 11101, the corresponding MAC control element is a MAC control element for the time forward command. In this case, the MAC control element for the time advance command may be 8 bits as one octet structure, and the number of bits used in the time advance command field TACF may be 6 bits. The remaining two bits are reserved bits.
On the other hand, when a plurality of serving cells are configured in the terminal, when the time advance command is given to the plurality of serving cells, the LCID field may be given as shown in Table 5.
Referring to Table 5, if the value of the LCID field is 11010, the corresponding MAC control element is a MAC control element for time advance commands for the plurality of serving cells. In this case, the MAC control element for the time advance command is, for example, six octets and has a total of 48 bits, and the number of bits used in the time advance command field (TACF) may be 11 bits. The remaining bits are used as reserved bits, uplink grants or as temporary C-RNTIs.
Meanwhile, the LCID field may identify that the MAC control elements 620-1,..., 620-n are MAC control elements for the random access response as shown in Table 6.
Referring to Table 6, if the value of the LCID field is 11010, the corresponding MAC control element is a MAC control element for the random access response of the secondary serving cell. In this case, the MAC control element for the random access response is, for example, p octets, and includes only 11-bit time forward command field (TACF), or in addition to the time forward command field, a backoff indicator field and an uplink grant. (uplink grant) may be included.
Padding 640 is a predetermined number of bits added to make the size of
7 is a block diagram illustrating a structure of a random access response message according to another example of the present invention.
Referring to FIG. 7, the random access response message may be configured in the format of the
The
Meanwhile, the
The
The
The BI field may be applied when the terminal determines that the random access procedure is not successful. For example, when the terminal fails to receive the random access response message when the terminal proceeds with the random access procedure later, including the current random access procedure, the terminal increases the number of random access procedure retries by one. If the increased number of random access procedure retries is less than or equal to the maximum number of retries set by the base station, the terminal may retry the random access procedure. In this case, when the UE receives the BI field and the backoff parameter value is not 0, the UE selects one of the value between the backoff parameter value and 0 based on the uniform probability distribution function.
The terminal delays the start or restart of the random access procedure by the selected value. For example, when the BI field value is '1000', this corresponds to a value of 8, so the backoff parameter value is 160ms according to Table 5 below. Therefore, the terminal selects one of the values within 0 to 160ms with the same probability. If the terminal selects 83ms, the terminal delays restart of the random access procedure for 83ms when it determines that the random access has failed, and restarts the random access procedure in the fastest subframe where the random access procedure is possible after 83ms.
The RAPID is information for confirming whether or not the RAR MAC PDU for the random access preamble transmitted by the corresponding terminal among the random access preambles transmitted through the same time / frequency resource by the multiple terminals. The subheaders 705-1, 705-2, ..., 705-n including the RAPID may include three fields, E, T, and RAPID. Here, the E field is a field indicating whether the corresponding subheader is the last subheader or not. The T field is a field indicating whether the corresponding subheader is a subheader including a RAPID or a backoff indicator subheader. The RAPID field is defined by 6 bits and represents information about a random access preamble allocated by the base station or a random access preamble selected by the terminal.
8 is an explanatory diagram illustrating a method of determining, by a terminal, a successful reception of a random access response message according to an embodiment of the present invention. This is a case where the terminal succeeds in receiving a random access response message.
Referring to FIG. 8, a terminal receives a random access start indicator indicating a start of a random access procedure from a base station in a specific serving cell. The random access start indicator is also called a PDCCH order. The terminal transmits the random access preamble to the base station through the PRACH in
There are five formats of the random access preamble as shown in Table 7.
Referring to Table 7, T CP is a parameter representing a section of a cyclic prefix (CP) of a PRACH symbol, T SEQ is a parameter representing a sequence section, and T S represents a sampling time. According to each format, the number of subframes occupied by the PRACH may be variably defined. For example, in the
The UE starts a random access window for checking whether a random access response message is received in
The UE receives the PDCCH scrambled with the C-RNTI and receives the PDSCH indicated by the PDCCH. The terminal then checks whether a random access response message exists in the data of the received PDSCH. This is called the processing time for P1. The random access response message may have a MAC PDU structure as shown in FIG. 6.
The terminal determines whether the random access response message has been successfully received. To this end, the terminal i) confirms whether the random access response message was received during the random access window period, and ii) confirms that the random access response message was received by the new transmission from the value of the new data indicator in the DCI mapped to the PDCCH. do. If all of the conditions i) and ii) are satisfied, the terminal is considered to have successfully received the random access response message. Here, in addition to the processing section for the P1, an additional processing section for determining whether there is a random access response message for the random access preamble transmitted by the UE through the secondary serving cell in the MAC PDU may be required. Therefore, the processing interval required to confirm whether the random access response message is received during the random access window interval may be larger than the processing interval for P1. For example, a total of 6 ms processing interval may be required by adding 3 ms of processing interval for P1 and 3 ms for checking whether a random access response message is present in the MAC layer.
Meanwhile, the terminal transmits an ACK signal indicating that the PDSCH has been successfully received to the base station in
9 is an explanatory diagram illustrating a method of determining, by a terminal, a reception success of a random access response message according to another embodiment of the present invention. This is a case where the terminal fails to receive the random access response message.
Referring to FIG. 9, a terminal receives a random access start indicator indicating a start of a random access procedure from a base station in a specific serving cell. The terminal transmits the random access preamble P1 to the base station through the PRACH in
The UE starts a random access window for confirming whether a random access response message is received in
The base station receives the P1, checks the C-RNTI of the terminal from the P1, and transmits the PDCCH1 scrambled with the C-RNTI and the PDSCH1 mapped with the random access response message to the terminal in
In connection with performing HARQ, the UE receives the PDCCH1 scrambled with the C-RNTI and fails to decode the PDSCH2 indicated by the PDCCH1. Accordingly, the terminal transmits the NACK signal to the base station in
Here, in order to determine successful reception of the random access response message, i) check whether a random access response message has been received during the random access window period, and ii) the random access response message is new from the value of the new data indicator in the DCI mapped to the PDCCH. Confirm that it was received by transmission. As a result of the check, the UE fails to decode the PDSCH and cannot know whether the PDSCH includes a random access response message. Therefore, since the condition of i) is not satisfied, the terminal is considered to have failed in receiving the random access response message.
If the reception success condition of the random access response message is not satisfied during the random access window period, the terminal transmits the random access preamble again based on the end time of the random access window. For example, the UE transmits the random access preamble P2 in
For example, if the decoding of the PDSCH indicating that the NDI is new data is successful in the last random access window subframe, a random access response message is received 6 ms later (subframe # 13) at the end of the random access window (subframe # 7). Since the UE can recognize the failure, the UE cannot transmit the random access preamble P2 in
Since the base station receives the NACK signal from the terminal, the base station retransmits the random access response message transmitted in
On the other hand, the base station transmits the PDSCH3 indicated by the PDCCH3 and PDCCH3 scrambled with the C-RNTI for the P2 to the UE in subframe # 15. In determining whether the random access response message is successfully received, the subframe # 15 belongs to the random access window section, and the new data indicator indicates new transmission, thereby satisfying both i) and ii) requirements. Accordingly, the terminal determines that the random access response message is successfully received.
10 is a flowchart illustrating a method of performing a random access procedure by a terminal according to an embodiment of the present invention.
Referring to FIG. 10, the terminal receives preamble allocation information from the base station (S1000). The terminal selects a dedicated random access preamble based on the preamble allocation information and transmits the selected dedicated random access preamble to the base station on the secondary serving cell (S1005).
The terminal starts the random access window (S1010), and determines whether the reception of the random access response message (RAR) is successful (S1015). Successful reception of the random access response message must satisfy the following two requirements. i) a requirement to receive the PDCCH scrambled with the C-RNTI of the UE and the PDSCH indicated by the PDCCH within the random access window interval, and ii) a requirement for the new data indicator in the PDCCH to indicate new transmission.
If both of the above requirements are satisfied, the terminal is considered to have successfully received the random access response message. The terminal analyzes the time advance command field in the random access response message to obtain a time alignment value, and aligns the uplink times of all serving cells in the time alignment group including the corresponding secondary serving cell based on the obtained time alignment value. (S1020). The terminal transmits an ACK signal to the base station according to the HARQ procedure (S1025).
On the other hand, if either of the two requirements are not satisfied, the terminal is considered to have failed in receiving the random access response message. Therefore, the terminal transmits a new random access preamble to the base station at a predetermined time point (S1030). And, the terminal transmits the ACK / NACK signal to the base station according to the HARQ procedure (S1025).
11 is a flowchart illustrating a method of performing a random access procedure by a base station according to an embodiment of the present invention.
Referring to FIG. 11, the base station transmits preamble allocation information to the terminal (S1100). The base station receives the dedicated random access preamble from the terminal on the secondary serving cell (S1105). The base station sets the value of the new data indicator (NDI) corresponding to the random access response message to either new transmission or retransmission (S1110). The base station generates a DCI including the new data indicator (S1115). The base station adds the CRC parity bit to the generated DCI (S1120), and scrambles the CRC parity bit with a unique C-RNTI of the terminal (S1125).
The base station transmits the PDCCH to which the DCI scrambled with the C-RNTI is mapped and the PDSCH indicated by the PDCCH and to which the random access response message is mapped (S1130). The random access response message includes a time forward command field, and the time forward command field indicates a time alignment value that is information about an uplink time to be adjusted in the secondary serving cell.
The base station receives an ACK / NACK signal from the terminal indicating the successful reception of the PDSCH (S1135).
12 is a block diagram illustrating a terminal and a base station according to an embodiment of the present invention.
Referring to FIG. 12, the terminal 1200 includes a receiver 1205, a
The receiver 1205 receives, from the
The information analyzing unit 1211 interprets the indications of the fields included in the DCI. For example, the information analysis unit 1211 determines whether the new data indicator means new transmission of the random access response message or retransmission of the random access response message. The information analyzing unit 1211 then transmits the determination result regarding the new transmission or retransmission of the random access response message to the random
The
For example, when the determination result of the information analyzing unit 1211 indicates new transmission of the random access response message, and the random access response message is received within the random access window section, the random
On the other hand, upon successful reception of the random access response message, the information analyzer 1211 analyzes the time advance command field in the random access response message to obtain a time alignment value. The
On the contrary, if the random access response message fails to be received, the
The transmitter 1220 transmits the random access preamble to the
The
The
The
The information generator 1271 sets the value of the new data indicator (NDI) corresponding to the random access response message to either new transmission or retransmission. The information generator 1271 generates a DCI including the new data indicator. The information generator 1271 adds a CRC parity bit to the generated DCI, scrambles the CRC parity bit with a unique C-RNTI of the terminal 1200, and sends the CRC parity bit to the
The random access processor 1272 measures an uplink time based on a random access preamble received on the secondary serving cell and calculates a time alignment value. In addition, the random access processing unit 1272 generates a random access response message including a time advance command field indicating a time alignment value, and sends the random access response message to the
When the ACK / NACK signal received by the
The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas falling within the scope of the same shall be construed as falling within the scope of the present invention.
Claims (12)
Transmitting a random access preamble to the base station on a secondary serving cell;
Starting a random access window (RA window);
On the secondary serving cell, a physical downlink control channel to which downlink control information (DCI) is mapped, including a new data indicator (NDI) indicating new transmission or retransmission of a random access response message, is mapped. Receiving from the base station; And
Based on whether the random access response message is received within the interval of the random access window and whether the new data indicator indicates new transmission, the random access response message is a physical downlink shared channel on the secondary serving cell And determining whether the reception is successful via the random access.
The random access response message includes a timing advance command (TAC) field indicating a time alignment value for adjusting an uplink time in the secondary serving cell.
If it is determined that the random access response message is successfully received, adjusting the uplink time in the secondary serving cell by using the time alignment value.
And the physical downlink control channel is scrambled with a cell-radio network temporary identifier (C-RNTI) which is a unique identifier of the terminal.
The random access response message is a method of performing a random access, characterized in that the protocol data unit (PDU) generated in the medium access control (MAC) layer of the base station.
Receiving preamble allocation information from the base station including preamble index and time / frequency resource information;
The random access preamble is transmitted based on the preamble index and the time / frequency resource information.
A receiving unit receiving a physical downlink control channel to which downlink control information (DCI) including a new data indicator (NDI) indicating new transmission or retransmission of a random access response message is mapped, from the base station on a secondary serving cell;
A transmitter for transmitting a random access preamble to the base station on a secondary serving cell;
An information analyzer for analyzing whether the new data indicator indicates new transmission; And
Generate the random access preamble, start a random access window (RA window) by transmitting the allocated random access preamble, and interpret the information and whether the random access response message is received within the interval of the random access window And a random access processing unit for determining whether the random access response message is successfully received based on a negative analysis result.
The receiving unit receives preamble allocation information including a preamble index and time / frequency resource information from the base station,
The random access processor generates the random access preamble based on the preamble index and the time / frequency resource information.
The transmitter is characterized in that for transmitting the random access preamble based on the preamble index and time / frequency resource information.
The random access response message, characterized in that it comprises a time advance command (TAC) field indicating a time alignment value for adjusting the uplink time in the secondary serving cell.
If it is determined that the random access response message is successfully received,
The random access processing unit, characterized in that for adjusting the uplink time in the secondary serving cell using the time alignment value.
Wherein the physical downlink control channel is scrambled with a Cell-Wireless Network Temporary Identifier (C-RNTI) which is a unique identifier of the terminal.
The random access response message is a terminal, characterized in that the protocol data unit (PDU) generated in the medium access control (MAC) layer of the base station.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020120008557A KR20130087308A (en) | 2012-01-27 | 2012-01-27 | Apparatus and method for performing random access in wireless communication system |
| PCT/KR2013/000641 WO2013112009A1 (en) | 2012-01-27 | 2013-01-25 | Apparatus and method for performing random access in wireless communication system |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020120008557A KR20130087308A (en) | 2012-01-27 | 2012-01-27 | Apparatus and method for performing random access in wireless communication system |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| KR20130087308A true KR20130087308A (en) | 2013-08-06 |
Family
ID=48873686
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| KR1020120008557A KR20130087308A (en) | 2012-01-27 | 2012-01-27 | Apparatus and method for performing random access in wireless communication system |
Country Status (2)
| Country | Link |
|---|---|
| KR (1) | KR20130087308A (en) |
| WO (1) | WO2013112009A1 (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016190667A1 (en) * | 2015-05-26 | 2016-12-01 | 삼성전자주식회사 | Method and device for performing random access in wireless communication system |
| WO2018012833A1 (en) * | 2016-07-11 | 2018-01-18 | 삼성전자 주식회사 | Method for effectively transmitting control message for random access |
| KR20190085422A (en) * | 2018-01-10 | 2019-07-18 | 삼성전자주식회사 | The method for efficient system information request in the next generation wireless communication systems |
| US10887922B2 (en) | 2016-07-11 | 2021-01-05 | Samsung Electronics Co., Ltd. | Method for effectively transmitting control message for random access |
| WO2022149629A1 (en) * | 2021-01-06 | 2022-07-14 | 엘지전자 주식회사 | Multidimensional syndrome-based ir method and device in qkd system |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9699807B2 (en) * | 2014-11-19 | 2017-07-04 | Intel IP Corporation | High-efficiency Wi-Fi (HEW) station and access point (AP) and method for random access contention |
| EP3494753B1 (en) | 2016-09-12 | 2021-06-02 | LG Electronics Inc. | Multiple random access preamble transmission for a single random access procedure |
| KR102509979B1 (en) * | 2017-06-07 | 2023-03-14 | 삼성전자 주식회사 | System and mehtod of identifying random access response |
| US20190313445A1 (en) * | 2018-04-05 | 2019-10-10 | Mediatek Inc. | Dl reception with consideration of qcl assumption |
| KR102444420B1 (en) * | 2018-05-10 | 2022-09-19 | 삼성전자 주식회사 | Method and apparatus for handling uplink time alignment in next generation wireless communication system |
| US20220141877A1 (en) * | 2019-02-15 | 2022-05-05 | Lg Electronics Inc. | Method by which terminal performs random access procedure in wireless communication system, and device therefor |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20070064665A1 (en) * | 2005-08-23 | 2007-03-22 | Interdigital Technology Corporation | Method and apparatus for accessing an uplink random access channel in a single carrier frequency division multiple access system |
| KR101519345B1 (en) * | 2008-01-01 | 2015-05-21 | 주식회사 팬택 | A method for transmitting and receiving random access request and transmitting and receiving random access response |
| NL2001465C2 (en) * | 2008-04-10 | 2009-10-13 | Riny Bay Sportswear | Counting and indication device and use thereof. |
| WO2010002130A2 (en) * | 2008-07-03 | 2010-01-07 | Lg Electronics Inc. | Method for processing ndi in random access procedure and a method for transmitting and receiving a signal using the same |
| US8982805B2 (en) * | 2010-04-09 | 2015-03-17 | Acer Incorporated | Activating component carriers by non-contention based random access procedure |
-
2012
- 2012-01-27 KR KR1020120008557A patent/KR20130087308A/en not_active Application Discontinuation
-
2013
- 2013-01-25 WO PCT/KR2013/000641 patent/WO2013112009A1/en active Application Filing
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016190667A1 (en) * | 2015-05-26 | 2016-12-01 | 삼성전자주식회사 | Method and device for performing random access in wireless communication system |
| KR20160138834A (en) * | 2015-05-26 | 2016-12-06 | 삼성전자주식회사 | Method and apparatus for performing random access in wireless communication system |
| US10440752B2 (en) | 2015-05-26 | 2019-10-08 | Samsung Electronics Co., Ltd. | Method and device for performing random access in wireless communication system |
| WO2018012833A1 (en) * | 2016-07-11 | 2018-01-18 | 삼성전자 주식회사 | Method for effectively transmitting control message for random access |
| US10887922B2 (en) | 2016-07-11 | 2021-01-05 | Samsung Electronics Co., Ltd. | Method for effectively transmitting control message for random access |
| KR20190085422A (en) * | 2018-01-10 | 2019-07-18 | 삼성전자주식회사 | The method for efficient system information request in the next generation wireless communication systems |
| US11844087B2 (en) | 2018-01-10 | 2023-12-12 | Samsung Electronics Co., Ltd. | Efficient system information request method and apparatus of terminal in next generation mobile communication system |
| WO2022149629A1 (en) * | 2021-01-06 | 2022-07-14 | 엘지전자 주식회사 | Multidimensional syndrome-based ir method and device in qkd system |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2013112009A1 (en) | 2013-08-01 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| KR101861694B1 (en) | Method and apparatus for transmitting data in wireless communication system | |
| US20120314652A1 (en) | Apparatus and method for performing random access in wireless communication system | |
| KR101892717B1 (en) | Method and appratus for transmitting uplink data in a wireless communication system | |
| EP2953415B1 (en) | Method of performing random access procedure in wireless communication system | |
| KR101810121B1 (en) | Apparatus and method for performing random access in wireless communication system | |
| CN111295866B (en) | Method and apparatus for transmitting and receiving random access preamble in wireless communication system | |
| US9642161B2 (en) | Cross-scheduling for random access response | |
| KR20130087308A (en) | Apparatus and method for performing random access in wireless communication system | |
| US20110249641A1 (en) | Apparatus and method for performing random access in multi-carrier system | |
| EP2640138A1 (en) | Reconfiguration of timing advance groups | |
| US20140092855A1 (en) | Apparatus and method for performing random access in wireless communication system | |
| KR20130097586A (en) | Apparatus and method for performing random access procedure in multiple component carrier system | |
| KR20120136481A (en) | Apparatus and method for performing uplink synchronization in multiple component carrier system | |
| CN111165063A (en) | Method for performing random access procedure and apparatus therefor | |
| KR20120136867A (en) | Apparatus and method for performing uplink synchronization in multiple component carrier system | |
| KR20130083708A (en) | Apparatus and method for performing random access in wireless communication system | |
| KR20130084176A (en) | Apparatus and method of transmitting uplink signal in wireless communication system | |
| KR20130032178A (en) | Apparatus and method for performing random access procedure in multiple component carrier system | |
| KR20200026706A (en) | Methods for controlling a random access operation in unlicensed spectrum and apparatuses thereof | |
| KR101911211B1 (en) | Apparatus and method for performing random access in wireless communication system | |
| KR20120132284A (en) | Apparatus and method for performing random access in wireless communication system | |
| WO2023181746A1 (en) | Terminal device, base station device, and communication method | |
| WO2023181710A1 (en) | Terminal device, base station device, and communication method | |
| KR20130031126A (en) | Apparatus and method for performing random access procedure in multiple component carrier system | |
| KR20130032806A (en) | Apparatus and method for performing random access procedure in multiple component carrier system |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| N231 | Notification of change of applicant | ||
| WITN | Withdrawal due to no request for examination |