WO2006123471A1 - Radio communication device and radio communication method - Google Patents

Radio communication device and radio communication method Download PDF

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Publication number
WO2006123471A1
WO2006123471A1 PCT/JP2006/304949 JP2006304949W WO2006123471A1 WO 2006123471 A1 WO2006123471 A1 WO 2006123471A1 JP 2006304949 W JP2006304949 W JP 2006304949W WO 2006123471 A1 WO2006123471 A1 WO 2006123471A1
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WO
WIPO (PCT)
Prior art keywords
packet
transmission
retransmission
capacity
data
Prior art date
Application number
PCT/JP2006/304949
Other languages
French (fr)
Japanese (ja)
Inventor
Yasuyuki Kato
Original Assignee
Sharp Kabushiki Kaisha
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sharp Kabushiki Kaisha filed Critical Sharp Kabushiki Kaisha
Priority to JP2007516216A priority Critical patent/JPWO2006123471A1/en
Publication of WO2006123471A1 publication Critical patent/WO2006123471A1/en

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0015—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy
    • H04L1/0017—Systems modifying transmission characteristics according to link quality, e.g. power backoff characterised by the adaptation strategy where the mode-switching is based on Quality of Service requirement
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1867—Arrangements specially adapted for the transmitter end
    • H04L1/1887—Scheduling and prioritising arrangements
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0002—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate
    • H04L1/0003—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission rate by switching between different modulation schemes
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0006—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission format
    • H04L1/0007—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the transmission format by modifying the frame length
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/0001—Systems modifying transmission characteristics according to link quality, e.g. power backoff
    • H04L1/0009—Systems modifying transmission characteristics according to link quality, e.g. power backoff by adapting the channel coding
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W72/00—Local resource management
    • H04W72/12—Wireless traffic scheduling
    • H04W72/1263—Mapping of traffic onto schedule, e.g. scheduled allocation or multiplexing of flows

Definitions

  • the present invention relates to a radio communication technique, and more particularly to a packet retransmission control technique in a communication system that adaptively changes a modulation scheme, a coding rate, and the like based on a radio channel state.
  • MCS Modulation and Code Scheme
  • the base station In a communication method using subcarrier adaptive modulation in which adaptive modulation is performed for each subcarrier based on the state of the wireless channel, the base station periodically changes the modulation method and coding rate according to the state of the wireless channel. Therefore, the data capacity differs for each transmission packet. Because the packet capacity for each transmission is different, the size of the retransmitted packet (packet capacity) that is retransmitted when the mobile station fails to receive the packet transmitted from the base station also varies depending on the radio propagation environment. . If a retransmission packet is retransmitted with the same packet capacity as the first transmission packet, it is transmitted with the same modulation method and coding rate as the first transmission packet.
  • FIG. 16 is a diagram showing such a general retransmission method.
  • the base station if the mobile station fails to receive the 200-bit packet (1) transmitted by the base station power, eg, QPSK (packet 1 failure), the base station indicates that it failed by returning NACK. To inform. The base station that has received the N ACK tries to retransmit the same packet (1) to the mobile station. In this case, an attempt is made to transmit a 200-bit packet 1 with the same QPSK. In such a case, there is a possibility that the state of the radio channel will change, and in QPSK, 200-bit packet 1 is a modulation scheme suitable for the radio channel at the time of retransmission. There is also a high possibility that reception will fail on the receiving side.
  • QPSK packet 1 failure
  • FIG. 17 is a diagram illustrating a retransmission packet transmission method according to Patent Document 1. As shown in FIG.
  • a base station that fails to receive a transmission 1 QPSK (200 bits) packet 1 uses packet 1 as a BPSK (100 bits) packet (1/2) and a BPSK packet. It is divided into (2/2) and transmitted to the mobile station in two steps.
  • a method of transmitting a retransmission packet by dividing it into a plurality of pieces has been proposed.
  • Patent Document 1 Japanese Unexamined Patent Application Publication No. 2004-349884
  • the initial packet is divided into a plurality of times several times. For example, if the retransmission packet is divided and sent as shown in Fig. 18, for example, the second retransmission packet 2 divided due to the change in the radio propagation environment. Depending on the radio propagation environment when transmitting (2/2), the initial packet capacity (200 bits) may be transmitted.
  • N_channel Stop and Wait method In the retransmission method using the method of retransmitting after N channels), if the packet is divided, the transmission time interval required until the retransmission packet transmission is completed becomes too large, resulting in an increase in transmission delay. There's a problem.
  • An object of the present invention is to increase effective throughput in communication when retransmission is involved in wireless communication.
  • the transmission packet capacity is calculated from the radio propagation path information, it is determined whether to transmit a new packet and a retransmission packet from the transmission packet capacity and the retransmission packet capacity, and based on the determination, Appropriate scheduling for packet transmission including retransmission packet transmission is performed to approximate the transmission packet capacity.
  • Appropriate scheduling for packet transmission including retransmission packet transmission is performed to approximate the transmission packet capacity.
  • a wireless communication system that performs communication by subcarrier adaptive modulation, and includes a modulation scheme and a coding rate for each subcarrier or each block based on wireless propagation path information.
  • a transmitter used in a wireless communication system that performs communication by determining the transmission capacity a transmission capacity is calculated based on the modulation scheme and the coding rate determined from the wireless propagation path information, and the calculated transmission capacity is calculated.
  • the retransmission capacity and the retransmission packet capacity calculated from the modulation scheme determined based on the radio propagation path information and the coding rate are approximate to each other. It is characterized by a condition for sending a packet. Further, when the transmission capacity is suitable for transmission of the retransmission packet, the retransmission packet is preferentially transmitted.
  • the retransmission determination means determines the number of retransmission determinations of a retransmission packet based on communication quality (Qos). When the communication quality is high, the number of retransmission determinations can be reduced to reduce the complexity of processing.
  • Qos communication quality
  • the retransmission determination means performs retransmission determination only within a certain retransmission delay time. Continuing the process related to packet retransmission makes the process complicated To prevent.
  • FIG. 1 is a functional block diagram showing a system configuration example of a base station belonging to a wireless communication system according to a first embodiment of the present invention.
  • FIG. 2 is a functional block diagram showing a system configuration example of a mobile station belonging to the radio communication system according to the first embodiment of the present invention.
  • FIG. 3 is a diagram showing a packet configuration example when a packet is sent to a mobile station in terms of base station power.
  • FIG. 4 is a diagram showing an example of a packet configuration when a packet is sent from a mobile station to a base station.
  • FIG. 5 is a flowchart showing a retransmission packet transmission processing algorithm according to the present embodiment.
  • FIG. 6A is a flowchart showing a retransmission packet transmission processing algorithm according to the present embodiment.
  • FIG. 6B is a flowchart showing a retransmission packet transmission processing algorithm according to the present embodiment following FIG. 6A.
  • FIG. 7 shows an example of packet retransmission.
  • FIG. 8 shows an example of packet retransmission.
  • FIG. 9 is a diagram showing an example of packet retransmission.
  • FIG. 10 shows an example of packet retransmission.
  • FIG. 11 shows an example of packet retransmission.
  • FIG. 12 An example of packet retransmission according to the second embodiment of the present invention (N—Channel Stop and
  • FIG. 1 A first figure.
  • FIG. 13 is a functional block diagram showing a configuration example of a transmission data control unit of the base station according to the first embodiment of the present invention.
  • FIG. 14 is a functional block diagram showing a configuration example (N—Channel Stop and Wait) of the transmission data control unit of the base station according to the second embodiment of the present invention.
  • FIG. 15A is a diagram showing a retransmission packet transmission processing algorithm (N_Channel Stop and Wait) according to the second embodiment of the present invention.
  • FIG. 15B is a diagram showing a retransmission packet transmission processing algorithm (N_Channel Stop and Wait) according to the second embodiment of the present invention following FIG. 15A.
  • FIG. 16 is a diagram illustrating a conventional packet retransmission example.
  • FIG. 17 is a diagram showing a conventional packet retransmission example.
  • FIG. 18 is a diagram illustrating a conventional packet retransmission example.
  • FIG. 19 is a diagram illustrating a conventional packet retransmission example.
  • FIG. 20 is a diagram showing a conventional packet retransmission example (N—Channel Stop and Wait). Explanation of symbols
  • a ... the base station is: 1 ... transmission data control unit, 3 ... data processing unit, 5 ... buffer, 7 ... pilot generation unit, 11 ... transmission data capacity calculation unit, 15- MCS allocation unit, 17 ... control Information processing unit, 21 ... propagation path information processing unit, 23 ... uplink reception processing unit, 25 ... wireless transmission unit, 27 ... wireless reception unit, ATI ... antenna.
  • a new packet is a packet that is sent for the first time
  • a retransmission packet is a packet that is sent at least once before.
  • FIG. 1 and 2 show wireless communication used in the wireless communication technology according to the embodiment of the present invention. It is a functional block diagram which shows the system configuration example of a system.
  • FIG. 1 is a diagram illustrating a configuration example of a base station
  • FIG. 2 is a diagram illustrating a configuration example of a mobile station.
  • the base station A includes a transmission data control unit 1, a data processing unit 3, and a buffer.
  • a pilot generation unit 7 a transmission data capacity calculation unit 11, an MCS allocation unit 15, a control information processing unit 17, a propagation path information processing unit 21, an uplink reception processing unit 23, and a radio transmission unit 25 And a radio receiver 27 and an antenna ATI.
  • New transmission data is input to transmission data control section 1 at base station A having the configuration shown in FIG. Whether the transmission data control unit 1 transmits a new packet and a retransmission packet as well as the transmission data capacity instructed by the transmission data capacity calculation unit 11 and the Ack / Nack information power of the previously transmitted packet from the control information processing unit 17.
  • the new transmission data is packetized and sent to the data processing unit 3.
  • the bucketed data is temporarily stored in the buffer 5 for retransmission processing.
  • the transmission data control unit 1 extracts the retransmission data stored in the buffer 5 and sends it to the data processing unit 3.
  • the packet data that has been successfully transmitted is erased from the buffer 5.
  • the data processing unit 3 performs the modulation method “modulation of data with a coding rate” specified by the MCS allocating unit 5 and passes the data to the wireless transmission unit 25. Also, at this time, the mobile station adds pilot data for performing channel estimation in the radio section and information on the modulation scheme for the data, ie, the code ratio.
  • the radio transmission unit 25 up-converts the data-modulated signal to a radio frequency band, and transmits the signal to the mobile station with the transmission power of each subcarrier constant.
  • the radio reception unit 27 down-converts the radio signal transmitted from the mobile station to the IF frequency band and passes it to the uplink reception processing unit 23.
  • Uplink reception processing section 23 demodulates the data-modulated signal and divides it into received data, propagation path estimation information, and control information.
  • Propagation path estimation information is transmitted to propagation path information processing section 21, and control information is control information.
  • the data is sent to the processing unit 17, and the received data is passed to the upper layer.
  • the propagation path information processing unit 21 converts the propagation path estimation information into propagation path data for MCS determination for each subcarrier performed by the MCS allocation unit 15 and sends it to the MCS allocation unit 15.
  • the MCS allocator 15 determines the MCS for each subcarrier from the propagation path data, and determines it.
  • Data processor 3 is controlled by the specified MCS.
  • the determined MCS information is sent to the transmission data capacity calculation unit 11.
  • the transmission data capacity calculation unit 11 calculates the transmission data capacity from the MCS information and passes the calculation result to the transmission data control unit 1.
  • the control information processing unit 11 extracts the Ack / Nack information of the transmission packet from the control information and passes it to the transmission data control unit 1.
  • the transmission data processing unit 3 includes a packet processing unit 3_1, a repacketizing unit 3_2, a new / retransmission packet determining unit 3_3, and a packet management unit. Part 3_4.
  • the packet management unit 3-4 shown in FIG. 13 determines the presence / absence of the retransmission packet, the packet number of the retransmission packet, and the data size based on the Ack / Nack information from the control information processing unit 17, and determines whether the packet is a new / retransmitted packet. Notify Part 3—3.
  • the new Z retransmission packet determination unit 3-3 determines whether to transmit a new packet or a retransmission packet from the retransmission packet information from the packet management unit 3-4 and the data size information from the transmission data capacity calculation unit 11. I do.
  • FIG. 2 is a functional block diagram showing a configuration example of the mobile station.
  • mobile station B in the radio communication system according to the present embodiment has antenna AT2, which receives a signal from the base station, radio reception unit 31, control information 'data separation unit 33, data
  • the processing unit 35, the MCS control unit 37, the packet determination unit 41, the propagation path information creation unit 45, the radio transmission unit 48, and the uplink transmission processing unit 47 are included.
  • Radio receiver 31 receives a radio signal from base station (A), down-converts the radio signal in the radio frequency band to IF frequency band, and converts the data-modulated signal into control information / data Send to remote part 33.
  • the control information / data separation unit 33 separates the data part and the control information, sends the data part to the data processing part 35, and sends the modulation method / coding rate information of the control information to the MCS control part 37 to obtain pilot data. Is sent to the propagation path information creation unit 45.
  • the data processing unit 35 performs demodulation processing according to an instruction from the MCS control unit 37, returns the packet data, and passes the packet data to the packet determination unit 41.
  • the packet determination unit 41 determines whether or not the received packet is correct, and sends success / failure information to the uplink transmission processing unit 47. If the received packet is correct, the data is sent to the upper layer. If the received packet is not correct, discard the packet or save it in buffer 5 ( Figure 1) for synthesis with the retransmitted packet.
  • the propagation path information creation unit 45 estimates the propagation path between the base station and the mobile station from the pilot data, and sends the propagation path estimation result to the uplink transmission processing unit 47.
  • the uplink transmission processing unit 47 adds the propagation path estimation result and the Ack / Nack information of the received packet to the transmission data, modulates the data, and passes it to the wireless transmission unit 48.
  • the data-modulated signal is up-converted to a radio frequency band and sent to the base station.
  • adaptive modulation control is not necessary for uplink communication control on the base station receiving side and mobile station transmitting side.
  • FIG. 3 is a diagram showing a configuration example of a packet frame transmitted from the base station to the mobile station.
  • a pilot signal 51 for the mobile station to perform channel estimation is arranged at the head of the packet frame 50, and then a modulation scheme for each subcarrier 'coding rate information 53 is arranged.
  • a packet determination flag 55 for determining a new / retransmission packet is arranged, and then the packet number 57 and data 58a are arranged in this order.
  • packet number 59 and data 58b are further arranged.
  • FIG. 4 is a diagram showing a configuration example of a packet frame transmitted from the mobile station to the base station.
  • propagation path estimation information 61 estimated by the mobile station is arranged at the head of the packet frame 60, and then AckZNack information 63 and data 65 are arranged in order.
  • Ack and Nack can be determined not only by a determination method based on notification from the mobile station but also by timer processing.
  • the method using the timer process includes a method of determining that the Ack is not returned even if a certain period of time has elapsed, and that it is a Nack.
  • Step S2 determines whether or not there is a packet to be retransmitted is confirmed from the Ack / Nack information notified from the mobile station. If there is a packet to be retransmitted (Yes), the process proceeds to step S6, and the modulation scheme / coding rate for each subcarrier is calculated from the propagation path information notified from the mobile station.
  • step S7 the transmission bit capacity of the transmission packet is calculated from the modulation scheme / code rate for each subcarrier calculated in step S6.
  • step S8 the calculated transmission bit capacity is compared with the retransmission packet capacity. As a result of comparing the calculated transmission bit capacity with the retransmission packet capacity, if the retransmission packet capacity has a relationship of (transmission bit capacity ⁇ retransmission packet capacity ⁇ transmission bit capacity- ⁇ ) (Yes), the retransmission packet is transmitted.
  • step S9 the packet identification flag is set to 1 and a retransmission packet is transmitted. For comparison between the capacity of the transmitted packet and the capacity of the retransmitted packet, all packets to be retransmitted are prioritized and packets with smaller packet numbers are transmitted.
  • step S10 If the retransmission packet capacity is not in the relationship of (transmission bit capacity ⁇ retransmission packet capacity ⁇ transmission bit capacity- ⁇ ) (No), proceed to step S10 and compare the calculated transmission bit capacity with the retransmission packet group capacity ( (If there are multiple retransmission packets). As a result of the comparison in step S10, if the retransmission packet capacity is in the relationship of (transmission bit capacity ⁇ retransmission packet group capacity ⁇ transmission bit capacity ⁇ ) (Yes), it is determined that the retransmission packet is suitable for transmission. Proceeding to step S12, the packet identification flag is set to 1 and a retransmission packet group is transmitted. In cases other than the above, it is determined that the packet is not suitable for retransmission packet transmission (No), and the process proceeds to step S11 where new data is packetized to the calculated transmission packet capacity and the packet identification flag is set to 0. To send a new packet.
  • step S2 If it is determined in step S2 that there is no retransmission bucket (No), the process proceeds to steps S3 and S4, and the modulation scheme for each subcarrier 'code rate factor also calculates the transmission bit capacity of the transmission packet.
  • the new data is packetized so as to have the calculated transmission packet capacity, the packet identification flag is set to 0, and a new packet is transmitted (step S5). Proceed from step S9, S12, S5 to end (step S13).
  • the base station transmits packet 1 for QPSK (200 bits) and the mobile station determines that reception has failed, the mobile station notifies the base station of Nack information. .
  • the base station that received the Nack information of packet 1 calculates the modulation method and coding rate for each subcarrier from the propagation path estimation information from the mobile station because packet 1 exists as a retransmission packet.
  • the transmission bit capacity of the next packet to be transmitted is calculated from the system coding rate. Determines whether or not to send retransmission packet 1 after packet 3 transmission.
  • the transmission bit capacity of the transmission packet is BPSK (lOObit), after transmission of packet 3, it is determined that new packet 4 is to be transmitted, and packet 4 is transmitted.
  • the transmission bit capacity is calculated in the same manner, and it is determined whether or not retransmission packet 1 is transmitted after packet 4 is transmitted. Since the transmission bit capacity of the transmission packet is QPSK (200 bits), it is determined that retransmission packet 1 can be transmitted after packet 4 is transmitted, and retransmission packet 1 (QPSK, 200 bits) is actually transmitted to the mobile station. Send to.
  • the base station transmits packet 1 for QPSK (200 bits) and the mobile station determines that reception has failed, the mobile station notifies the base station of Nack information.
  • the base station that has received the Nack information of packet 1 calculates the modulation rate for each subcarrier from the propagation path estimation information from the mobile station because the packet 1 exists as a retransmission packet. Based on the modulation scheme coding rate, the transmission bit capacity of the packet to be transmitted next is calculated.
  • After sending bucket 3, determine whether to send resend packet 1 or not. Since the transmission bit capacity of the transmission packet at this time is BPSK (400 bits), after packet 3 is transmitted, it is determined that new packet 4 is to be transmitted, and new packet 4 is transmitted.
  • BPSK 400 bits
  • the transmission bit capacity is calculated in the same manner, and it is determined whether or not retransmission packet 1 is transmitted after packet 4 is transmitted.
  • the transmission bit capacity of the transmission packet is QPSK (200 bits)
  • it is determined that retransmission packet 1 is transmitted after transmission of new packet 4 and retransmission packet 4 is transmitted.
  • packet 1 is transmitted from the base station for QPSK (200 bits)
  • the mobile station determines that reception has failed, and the mobile station notifies the base station of Nack information.
  • the base station that has received the Nack information of packet 1 calculates the modulation method 'coding rate for each subcarrier from the propagation path estimation information from the mobile station because packet 1 exists as a retransmission packet, and calculates the calculated modulation.
  • Method The transmission bit capacity of the next packet to be transmitted is calculated from the coding rate. Determine whether or not to send resend packet 1 after sending packet 3. Since the transmission bit capacity of the transmission packet at this time is 16QAM (400 bits), it is determined that new packet 4 will be transmitted after packet 3 is transmitted, and new packet 4 is transmitted. Similarly, assume that Nack information is received for packet 2 when new packet 4 is transmitted.
  • the transmission bit capacity is calculated in the same manner, and it is determined whether the retransmission packet 1 or the retransmission packet 2 is transmitted after the new packet 4 is transmitted. Since the transmission bit capacity of the transmission packet is 16QAM (400 bits), there is not enough room to transmit only retransmission packet 1 or retransmission packet 2, so whether retransmission packet 1 and retransmission packet 2 are transmitted again. Judge about. Since the transmission bit capacity of the transmission packet is 16QAM (400 bits), it is judged that transmission is possible by combining packet 1 and packet 2. Therefore, after transmission of new packet 4, retransmission packet 1 and retransmission It is determined that packet 2 is to be transmitted, and retransmission packet 1 and retransmission packet 2 can be actually transmitted in one transmission. In this way, sending a plurality of retransmitted packets in one packet transmission is also an option for judgment depending on the condition of the communication path.
  • step S29 the number N of retransmission packet determinations is checked. If the number of determinations N is greater than or equal to the number of repetitions X (No), go to step S32 and set the packet identification flag to 1 and send a retransmission packet. If transmission is not possible at one time, the packet is divided and sent, or the first modulation method is used, such as transmission at the coding rate.
  • step S29 If the determination number N is less than the repetition number X (Yes) in step S29, the process proceeds to step S30, and the calculated transmission bit capacity is compared with the retransmission packet capacity. As a result of the comparison, if the retransmission packet capacity is in the relationship of (transmission bit capacity ⁇ retransmission packet capacity ⁇ transmission bit capacity 1), it is determined that the retransmission packet is suitable for transmission (Yes), and step S31 In step S32, the packet identification flag is set to 1, and a retransmission packet is transmitted in step S32.
  • the comparison step between the transmission packet capacity and the retransmission packet capacity in step S30 is performed for all the packets to be retransmitted, and a packet with a small packet number is preferentially transmitted. If the retransmission packet capacity is not in the relationship (transmission bit capacity ⁇ retransmission packet capacity ⁇ transmission bit capacity a) No), proceed to step S33 and compare the calculated transmission bit capacity with the retransmission packet group capacity (multiple retransmission If there are packets).
  • the process proceeds to step S34 (Yes), Set the packet identification flag to 1 and send the retransmission packet group.
  • the packet identification flag is set to 0. Send a new packet. The above is repeated while the retransmission packet exists.
  • step S22 If there is no retransmission packet in step S22 (No), the process proceeds to step S23, and the transmission bit capacity of the transmission packet is calculated from the calculated modulation scheme and coding rate for each subcarrier.
  • step S24 new data is packetized so as to have the calculated transmission packet capacity, the packet identification flag is set to 0, and a new packet is transmitted in step S25. It should be noted that the retransmission packet determination process can be varied N times for each data in consideration of the data QoS.
  • the number of repetitions X is 3.
  • the base station transmits packet 1 for QPS K (200 bits) and the mobile station determines that reception has failed, the mobile station notifies the base station of Nack information.
  • the base station that has received the Nack information of packet 1 calculates the modulation scheme for each subcarrier from the propagation path estimation information from the mobile station because packet 1 exists as a retransmission packet.
  • the transmission bit capacity of the next packet to be transmitted is calculated from the modulation scheme coding rate. Since the number of retransmission determinations is the first time (first time), it is determined whether or not retransmission packet 1 is transmitted after packet 3 is transmitted.
  • the transmission bit capacity of the transmission packet at this time is 3 ⁇ 4 PSK (lOObit) (lOObit) (lOObit)
  • the base station transmits packet 1 with QPSK (200 bits) and the mobile station determines that reception has failed, the mobile station notifies the base station of Nack information.
  • the base station that has received the Nack information of packet 1 calculates the modulation method 'coding rate for each subcarrier based on the propagation path estimation information from the mobile station because packet 1 exists as a retransmission packet.
  • the transmission bit capacity of the next packet to be transmitted is calculated from the coded modulation method coding rate. Then, since the number of retransmission determinations is the first time (first time), it is determined whether or not retransmission packet 1 is transmitted after packet 3 is transmitted.
  • the transmission bit capacity of the transmission packet at this time is 16QAM (400 bits)
  • the transmission bit capacity is calculated in the same manner, and it is determined whether or not retransmission packet 1 is transmitted.
  • the transmission bit capacity of the transmission packet is 16QAM (400 bits)
  • Send packet 5 After transmission, the transmission bit capacity is calculated in the same manner. The number of times of determination is the third time, and since the transmission bit capacity at this time is 16QAM, it matches the number of repetitions of determination, so a retransmission packet is transmitted.
  • the number of repetitions of determination may be used as a reference for transmitting a retransmission packet.
  • the retransmission control technique according to the present embodiment applies the N_Channel Stop and Wait method.
  • FIG. 14 is a diagram illustrating a configuration example of the transmission data processing unit in the N_Channel Stop and Wait method, and the configuration of the transmission data processing unit 3 of the base station will be described.
  • the transmission data processing unit 3 includes a packet reception unit 3 _ 1, a repacketization unit 3 _ 2, a new / retransmission packet determination unit 3 _ 3, a packet management unit 3 _ 4, a channel And a control unit 3_5.
  • the repacketizing unit 3-2 is connected to the buffer 5.
  • the packet management unit 3-4 determines the presence / absence of a retransmission packet, the packet number of the retransmission packet, and the data size, and determines the new / retransmission packet. Notify Part 3—3. Also, erase the data of successfully transmitted packet from buffer 5, or check the data size of the retransmitted packet.
  • the new / retransmission packet determination unit 3-3 transmits a new packet or determines a retransmission packet based on the retransmission packet information from the packet management unit 3-4 and the data size information from the transmission data capacity calculation unit. Determine whether to send.
  • the repacketizing unit 3-2 repackets the retransmitted packet data from the buffer 5 and sends it to the channel control unit 3-5.
  • the channel control unit 3-5 adds channel information to the data from the packet input unit 3-1, and performs a check based on the information from the new Z retransmission packet determination unit 3-3. Control channel switching.
  • FIGS. 15A and 15B are diagrams showing an N-Channel Stop and Wait method retransmission packet transmission processing algorithm according to the present embodiment.
  • the retransmission packet transmission processing algorithm (S41) will be described below.
  • step S42 it is confirmed whether there is a packet to be retransmitted from the Ack / Nack information notified from the mobile station.
  • step S42 if there is a retransmitted packet to be retransmitted in X—CH (Yes), the process proceeds to step S46, and the next X—CH subcarrier is determined from the X—CH propagation path information notified from the mobile station.
  • the modulation method 'coding rate is calculated.
  • step S43 the transmission bit capacity (data size) of the transmission packet of the next X_CH is calculated from the calculated modulation scheme for each subcarrier 'coding rate.
  • step S48 the calculated transmission bit capacity is compared with the retransmission packet capacity. As a result of the comparison in step S48, if the retransmission packet capacity is in the relationship of (transmission bit capacity ⁇ retransmission packet capacity ⁇ transmission bit capacity one), it is determined that it is suitable for retransmission packet transmission (Yes), Set the packet identification flag to 1, and in step S49, send the retransmission packet using X-CH.
  • step S50 If the retransmission packet capacity is not in the relationship of (transmission bit capacity ⁇ retransmission packet capacity ⁇ transmission bit capacity—a) (No), go to step S50 and calculate (X-1) —CH transmission Compare bit capacity and retransmission packet capacity. As a result of the comparison, if the retransmission packet capacity is in the relationship of ((X — 1) —CH transmission bit capacity ⁇ retransmission packet capacity ⁇ (X-1) CH transmission bit capacity ⁇ ), ( ⁇ es) Is determined to be suitable for transmission, the packet identification flag is set to 1, and a retransmission packet is transmitted at the timing (X ⁇ 1) —CH in step S51.
  • step S52 the new packet of (X-1) -CH is re-packeted so that it can be transmitted at the timing of X-CH.
  • step S53 the new packet of (X_l) -CH is transmitted with X-CH. Is sent out.
  • step S 54 If (X- 1) _ CH transmission bit capacity ⁇ retransmission packet capacity ⁇ (X- 1) _ CH transmission bit capacity—e) (No), go to step S 54 ( X—1) —CH sends a new packet of (X—1) —CH.
  • step S55 the transmission bit capacity to be transmitted by (X + 1) _CH is calculated from the propagation path information, and in step S56, the data size of the transmission packet is also calculated by the modulation / coding scheme power for each subcarrier. Then step In step S57, the transmission bit capacity of (X + l) —CH is compared with the retransmission packet capacity.
  • step S58 if the retransmission packet capacity has a relationship of ((X + l) —CH transmission bit capacity ⁇ Retransmission packet capacity ⁇ (X + l) —CH transmission bit capacity ⁇ ), the process proceeds to step S58, and (X + 1) Re-packetize the new packet of _CH, determine that it is suitable for sending the retransmit packet at the timing of (X + 1) _CH, and send the new packet of (X + l) -CH at the timing of X-CH. (Step S59), (X + l) —The retransmission packet of X—CH is transmitted at the timing of CH (step S60).
  • step S61 X-CH transmits a new packet of X-CH.
  • step S62 (X + 1) —CH (X + l) —Sends a new CH packet.
  • step S42 If there is no retransmission packet in step S42 (No), the transmission bit capacity of the transmission packet is calculated from the modulation scheme and coding rate for each subcarrier calculated in step S43.
  • step S44 new data is packetized so as to have the calculated transmission packet capacity, the packet identification flag is set to 0, and in step S45, a new packet is transmitted by X-CH.
  • base station power packet 1 (CH 1) is transmitted in QPSK (200 bits), and when the mobile station determines that reception has failed, the mobile station sends Nack information (including propagation path estimation information) to the base station. To be notified.
  • the base station that received the Nack information of packet 1 (CH1) at the time of packet 3 (CH3) transmission has packet 1 (CHI) as a retransmitted packet, so modulation for each subcarrier is determined from the channel estimation information from the mobile station.
  • System 'coding rate is calculated, and the transmission bit capacity of the packet transmitted on CH1 is calculated from the calculated modulation method coding rate.
  • the transmission bit capacity of CH1 is calculated as BPSK (100bit), and retransmission packet 1 cannot be transmitted.
  • the calculated CH4 transmission bit capacity is compared with the retransmission packet capacity.
  • the transmission bit capacity of CH4 is BPSK (lOObit)
  • a retransmission packet cannot be transmitted, and a new packet 4 is transmitted.
  • ACK information of packet 2 (CH2) is received when new packet 4 is transmitted, the transmission bit capacity in the next CH2 is calculated from the propagation path estimation information, and the transmission capacity of CH2 is compared with the retransmission packet capacity.
  • the transmission capacity of CH2 is QPSK (200bit) Therefore, it is determined that the retransmission packet can be transmitted at the timing of CH2, and CH1 and CH2 are exchanged and transmitted to the mobile station. In this way, it is also possible to perform transmission by switching channels.
  • the reliability of the retransmission packet may be slightly lowered because the packet is combined. It is also possible to increase the transmission packet capacity by increasing the transmission packet capacity and setting a low threshold value for determining the modulation method used for the retransmitted packet that is desired to be completed after one transmission.
  • the transmission bit capacity is calculated, and it is determined whether to transmit a new packet or a retransmission packet from the transmission capacity.
  • a packet radio communication system that performs adaptive control of radio parameters for each subcarrier
  • a packet radio communication system that performs adaptive control of radio parameters for each block by combining a plurality of subcarriers into one block.
  • the technique according to the present embodiment can also be applied to this. In this case, the present technology may be applied by considering one block as equivalent to the subcarrier.
  • the present invention is applicable to a communication device that uses packet communication.

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Abstract

It has been difficult to increase the actual throughput in communication when retransmission accompanies radio communication. A transmission packet capacity is calculated from radio propagation path information. It is decided whether to transmit a new packet or a retransmission packet from the transmission packet capacity and the retransmission packet capacity. By performing optima packet scheduling, it becomes possible to optimize the transmission containing a retransmission packet and increase the actual throughput in the radio communication.

Description

明 細 書  Specification
無線通信装置及び無線通信方法  Wireless communication apparatus and wireless communication method
技術分野  Technical field
[0001] 本発明は、無線通信技術に関し、特に、無線伝搬路状態に基づいて変調方式や 符号化率などを適応的に変化させる通信システムにおけるパケット再送制御技術に 関する。  TECHNICAL FIELD [0001] The present invention relates to a radio communication technique, and more particularly to a packet retransmission control technique in a communication system that adaptively changes a modulation scheme, a coding rate, and the like based on a radio channel state.
背景技術  Background art
[0002] 現在、高速移動体通信の分野において、無線基地局と無線移動局との間の無線 伝搬路状態に応じて、サブキャリア毎に変調方式'符号化率 (MCS : Modulation a nd Code Scheme、以下、「MCS」と称する。）を制御することにより伝送効率を高 め、高スループットの通信を提供する適応変調方式の研究 ·開発が行われている。さ らに、高スループットの通信を実現するために、 H— ARQのような再送方法が検討さ れている。  [0002] Currently, in the field of high-speed mobile communication, depending on the state of the radio channel between a radio base station and a radio mobile station, a modulation scheme (MCS: Modulation and Code Scheme) is set for each subcarrier. (Hereinafter referred to as “MCS”), research and development of adaptive modulation schemes that improve transmission efficiency and provide high-throughput communication is underway. Furthermore, in order to realize high-throughput communication, retransmission methods such as H-ARQ are being studied.
[0003] このような無線伝搬路状態に基づいてサブキャリア毎に適応変調させるサブキヤリ ァ適応変調による通信方式では、基地局は周期的に無線伝搬路の状態により変調 方式 ·符号化率を変化させるために送信パケット毎にデータ容量が異なる。送信毎の パケット容量が異なるため、基地局から送信されたパケットに関して、移動局側で受 信に失敗した場合に再送される再送パケットのサイズ (パケット容量)も、無線伝搬環 境により異なってしまう。再送パケットを初回送信パケットと同じパケット容量で再送し ようとすると、初回送信パケットと同様の変調方式、符号化率で送信することになる。 図 16に、このような一般的な再送方法を示す図である。図 16に示すように、基地局 力 例えば QPSKで送信された 200ビットのパケット（1)の受信に移動局が失敗した 場合に (パケット 1失敗）、 NACKを返すことにより失敗した旨を基地局に知らせる。 N ACKを受け取った基地局は、同じパケット（1)を移動局に対して再送しょうとする。こ の場合に、同じ QPSKで 200ビットのパケット 1を送信しょうとする。このような場合に、 無線伝搬路状態の変化が生じる可能性があり、 QPSKで 200ビットのパケット 1が再 送時の無線伝搬路に適した変調方式'符号化率でないことにより再度の送信パケット も受信側で受信失敗になってしまう可能性も高い。 [0003] In a communication method using subcarrier adaptive modulation in which adaptive modulation is performed for each subcarrier based on the state of the wireless channel, the base station periodically changes the modulation method and coding rate according to the state of the wireless channel. Therefore, the data capacity differs for each transmission packet. Because the packet capacity for each transmission is different, the size of the retransmitted packet (packet capacity) that is retransmitted when the mobile station fails to receive the packet transmitted from the base station also varies depending on the radio propagation environment. . If a retransmission packet is retransmitted with the same packet capacity as the first transmission packet, it is transmitted with the same modulation method and coding rate as the first transmission packet. FIG. 16 is a diagram showing such a general retransmission method. As shown in Fig. 16, if the mobile station fails to receive the 200-bit packet (1) transmitted by the base station power, eg, QPSK (packet 1 failure), the base station indicates that it failed by returning NACK. To inform. The base station that has received the N ACK tries to retransmit the same packet (1) to the mobile station. In this case, an attempt is made to transmit a 200-bit packet 1 with the same QPSK. In such a case, there is a possibility that the state of the radio channel will change, and in QPSK, 200-bit packet 1 is a modulation scheme suitable for the radio channel at the time of retransmission. There is also a high possibility that reception will fail on the receiving side.
[0004] そこで、初回送信時と同じ条件ではなぐ再送時における無線伝搬環境に応じて、 必要に応じて、変調方式 ·符号ィ匕率を初回送信時とは変化させて再送パケットを送 信することが望ましい。しかながらし、無線伝搬環境に応じて変調方式'符号化率を 変化させるため、再送時の送信パケット容量が初回送信時の送信パケット容量と異な る場合が多くなる。図 17は、特許文献 1にかかる再送パケットの送信方法を示す図で ある。図 17に示すように、特許文献 1では、送信 QPSK (200ビット）のパケット 1の受 信に失敗した基地局は、パケット 1を、 BPSK (100ビット）パケット（1/2)と BPSKパ ケット（2/2)とに分割し、 2回に分けて移動局に送信している。このように、再送時の 送信パケット容量が少ない場合に関しては、再送パケットを複数に分割して送信する 方法が提案されている。  [0004] Therefore, depending on the radio propagation environment at the time of retransmission that is not under the same conditions as at the time of initial transmission, the retransmission method is used to change the modulation method and code rate as compared with the time of initial transmission as necessary. It is desirable. However, since the modulation method 'coding rate is changed according to the radio propagation environment, the transmission packet capacity at the time of retransmission often differs from the transmission packet capacity at the time of initial transmission. FIG. 17 is a diagram illustrating a retransmission packet transmission method according to Patent Document 1. As shown in FIG. 17, in Patent Document 1, a base station that fails to receive a transmission 1 QPSK (200 bits) packet 1 uses packet 1 as a BPSK (100 bits) packet (1/2) and a BPSK packet. It is divided into (2/2) and transmitted to the mobile station in two steps. As described above, in the case where the transmission packet capacity at the time of retransmission is small, a method of transmitting a retransmission packet by dividing it into a plurality of pieces has been proposed.
特許文献 1 :特開 2004— 349884号公報  Patent Document 1: Japanese Unexamined Patent Application Publication No. 2004-349884
発明の開示  Disclosure of the invention
発明が解決しょうとする課題  Problems to be solved by the invention
[0005] しかしながら、図 17に示す特許文献 1の技術のように、再送時に無線伝播環境によ り送信パケット容量が少ないと算出された場合おいて、初回パケットを複数個に分割 して数回に分けて再送した時に、例えば図 18に示すように再送パケットを分割して送 ろうとする場合に、無線伝搬環境が変化していることに起因して、例えば分割された 2 番目の再送パケット 2 (2/2)を送信する時の無線伝搬環境により初回パケット容量 分（200ビット）を送信できる状態になる場合がある。このような場合でも、 1番目の再 送パケット（1/2)を既に送っているために、 2番目の再送パケット（2/2)において は残りのデータ容量分のみを再送パケットとして送信すれば十分になっているため、 結果として 2番目の再送パケット (2/2)の能力を十分に生力していないことになる。  However, as in the technique of Patent Document 1 shown in FIG. 17, when it is calculated that the transmission packet capacity is small due to the radio propagation environment during retransmission, the initial packet is divided into a plurality of times several times. For example, if the retransmission packet is divided and sent as shown in Fig. 18, for example, the second retransmission packet 2 divided due to the change in the radio propagation environment. Depending on the radio propagation environment when transmitting (2/2), the initial packet capacity (200 bits) may be transmitted. Even in such a case, since the first retransmission packet (1/2) has already been sent, if only the remaining data capacity is transmitted as the retransmission packet in the second retransmission packet (2/2), As a result, the second retransmission packet (2/2) does not have enough capacity as a result.
[0006] 逆に、図 19に示すように、送信パケット容量が初回パケット（QPSK: 200ビット）に 比べて十分に大きい場合においても（この場合では、 16QAM : 400ビット）、再送パ ケットは初回パケット容量分のみだけを送信するため、伝送効率が悪ぐスループット が上らなかった。  [0006] Conversely, as shown in FIG. 19, even if the transmission packet capacity is sufficiently larger than the initial packet (QPSK: 200 bits) (in this case, 16QAM: 400 bits), the retransmission packet is the first time. Since only the packet capacity was sent, the transmission efficiency was poor and the throughput did not increase.
[0007] 加えて、図 20に示すように、 N_channel Stop and Wait方式（失敗した場合 に Nチャネル後に再送する方式）を利用した再送方法では、パケットを分割してしまう と、再送パケットの送信完了までに必要な送信時間間隔が大きくなりすぎて、伝送遅 延が大きくなつてしまうという問題がある。 [0007] In addition, as shown in Fig. 20, N_channel Stop and Wait method (in case of failure) In the retransmission method using the method of retransmitting after N channels), if the packet is divided, the transmission time interval required until the retransmission packet transmission is completed becomes too large, resulting in an increase in transmission delay. There's a problem.
[0008] 本発明は、無線通信において、再送を伴う場合において通信における実効スルー プットを上げることを目的とする。 [0008] An object of the present invention is to increase effective throughput in communication when retransmission is involved in wireless communication.
課題を解決するための手段  Means for solving the problem
[0009] 本発明によれば、無線伝搬路情報から送信パケット容量を算出し、送信パケット容 量と再送パケット容量から、新規パケットと再送パケットを送信するかどうかを判定し、 判定に基づいて、送信パケット容量と近似させるように、再送パケットの送信を含むパ ケット送信に関する適正なスケジューリングを行う。適正なスケジューリングを行う場合 に、再送パケットの分割などの処理を行うことも考慮する。  [0009] According to the present invention, the transmission packet capacity is calculated from the radio propagation path information, it is determined whether to transmit a new packet and a retransmission packet from the transmission packet capacity and the retransmission packet capacity, and based on the determination, Appropriate scheduling for packet transmission including retransmission packet transmission is performed to approximate the transmission packet capacity. When performing proper scheduling, consider processing such as retransmission packet division.
[0010] すなわち、本発明の一観点によれば、サブキャリア適応変調により通信を行う無線 通信システムであって、無線伝搬路情報に基づいてサブキャリア毎又はブロック毎に 変調方式と符号化率とを決定して通信を行う無線通信システムに用いられる送信機 において、前記無線伝搬路情報から決定された前記変調方式と前記符号化率とに 基づいて送信容量を算出し、算出された送信容量に基づいて送信対象として再送パ ケットと新規パケットとのいずれを送信するかを判定する再送判定手段を有することを 特徴とする送信機が提供される。  [0010] That is, according to one aspect of the present invention, there is provided a wireless communication system that performs communication by subcarrier adaptive modulation, and includes a modulation scheme and a coding rate for each subcarrier or each block based on wireless propagation path information. In a transmitter used in a wireless communication system that performs communication by determining the transmission capacity, a transmission capacity is calculated based on the modulation scheme and the coding rate determined from the wireless propagation path information, and the calculated transmission capacity is calculated. There is provided a transmitter characterized by having retransmission determination means for determining whether to transmit a retransmission packet or a new packet as a transmission target.
[0011] 一形態によれば、前記無線伝搬路情報に基づいて決定された前記変調方式と前 記符号化率とから算出した送信容量と再送パケット容量とが近似していることを、再 送パケットを送るための条件とすることを特徴とする。また、前記送信容量が、前記再 送パケットの送信に適している場合には、該再送パケットを優先して送信することを特 徴とする。  [0011] According to one aspect, the retransmission capacity and the retransmission packet capacity calculated from the modulation scheme determined based on the radio propagation path information and the coding rate are approximate to each other. It is characterized by a condition for sending a packet. Further, when the transmission capacity is suitable for transmission of the retransmission packet, the retransmission packet is preferentially transmitted.
[0012] 前記再送判定手段は、通信品質 (Qos)に基づいて再送パケットの再送判定回数を 決定することを特徴とする。通信品質が高い場合には、再送判定回数を小さくして、 処理の煩雑さを低減することができる。  [0012] The retransmission determination means determines the number of retransmission determinations of a retransmission packet based on communication quality (Qos). When the communication quality is high, the number of retransmission determinations can be reduced to reduce the complexity of processing.
[0013] 前記再送判定手段は、ある再送遅延時間内に限って再送判定を行うことを特徴と する。パケットの再送に関する処理をいつまでも継続することが処理を煩雑にすること を防止する。 [0013] The retransmission determination means performs retransmission determination only within a certain retransmission delay time. Continuing the process related to packet retransmission makes the process complicated To prevent.
[0014] 通信品質 (Qos)に基づいて再送に関する判定間隔を変更することが好ましい。通 信品質が良くなつた場合には、判定間隔を短くして早めに再パケットを送る。  [0014] It is preferable to change the determination interval regarding retransmission based on communication quality (Qos). If the communication quality is improved, the re-packet is sent earlier with a shorter determination interval.
発明の効果  The invention's effect
[0015] 無線伝搬路情報から送信パケット容量を算出し、送信パケット容量と再送パケット容 量から、新規パケットまたは再送パケットを送信するかどうか判定し、最適なパケットス ケジユーリングを行うことにより、再送パケットを含む送信に関する適正化が可能となり 、無線通信における実効スループットが向上するという利点がある。  [0015] By calculating the transmission packet capacity from the radio channel information, determining whether to transmit a new packet or a retransmission packet from the transmission packet capacity and the retransmission packet capacity, and performing optimal packet scheduling, the retransmission packet As a result, it is possible to optimize the transmission including data, and to improve the effective throughput in wireless communication.
図面の簡単な説明  Brief Description of Drawings
[0016] [図 1]本発明の第 1の実施の形態による無線通信システムに属する基地局のシステム 構成例を示す機能ブロック図である。  FIG. 1 is a functional block diagram showing a system configuration example of a base station belonging to a wireless communication system according to a first embodiment of the present invention.
[図 2]本発明の第 1の実施の形態による無線通信システムに属する移動局のシステム 構成例を示す機能ブロック図である。  FIG. 2 is a functional block diagram showing a system configuration example of a mobile station belonging to the radio communication system according to the first embodiment of the present invention.
[図 3]基地局力も移動局へパケットが送られた場合のパケットの構成例を示す図であ る。  FIG. 3 is a diagram showing a packet configuration example when a packet is sent to a mobile station in terms of base station power.
[図 4]移動局から基地局へパケットが送られた場合のパケットの構成例を示す図であ る。  FIG. 4 is a diagram showing an example of a packet configuration when a packet is sent from a mobile station to a base station.
[図 5]本実施の形態による再送パケット送信処理アルゴリズムを示すフローチャート図 である。  FIG. 5 is a flowchart showing a retransmission packet transmission processing algorithm according to the present embodiment.
[図 6A]本実施の形態による再送パケット送信処理アルゴリズムを示すフローチャート 図である。  FIG. 6A is a flowchart showing a retransmission packet transmission processing algorithm according to the present embodiment.
[図 6B]図 6Aに続く本実施の形態による再送パケット送信処理アルゴリズムを示すフ ローチャート図である。  FIG. 6B is a flowchart showing a retransmission packet transmission processing algorithm according to the present embodiment following FIG. 6A.
[図 7]パケット再送例を示す図である。 FIG. 7 shows an example of packet retransmission.
[図 8]パケット再送例を示す図である。  FIG. 8 shows an example of packet retransmission.
[図 9]パケット再送例を示す図である。  FIG. 9 is a diagram showing an example of packet retransmission.
[図 10]パケット再送例を示す図である。  FIG. 10 shows an example of packet retransmission.
[図 11]パケット再送例を示す図である。 [図 12]本発明の第 2の実施の形態によるパケット再送例（N— Channel Stop andFIG. 11 shows an example of packet retransmission. [FIG. 12] An example of packet retransmission according to the second embodiment of the present invention (N—Channel Stop and
Wait)を示す図である。 FIG.
[図 13]本発明の第 1の実施の形態による基地局の送信データ制御部の構成例を示 す機能ブロック図である。  FIG. 13 is a functional block diagram showing a configuration example of a transmission data control unit of the base station according to the first embodiment of the present invention.
[図 14]本発明の第 2の実施の形態による基地局の送信データ制御部の構成例（N— Channel Stop and Wait)を示す機能ブロック図である。  FIG. 14 is a functional block diagram showing a configuration example (N—Channel Stop and Wait) of the transmission data control unit of the base station according to the second embodiment of the present invention.
[図 15A]本発明の第 2の実施の形態による再送パケット送信処理アルゴリズム（N_ C hannel Stop and Wait)を示す図である。  FIG. 15A is a diagram showing a retransmission packet transmission processing algorithm (N_Channel Stop and Wait) according to the second embodiment of the present invention.
[図 15B]図 15Aに続ぐ本発明の第 2の実施の形態による再送パケット送信処理アル ゴリズム（N _ Channel Stop and Wait)を示す図である。  FIG. 15B is a diagram showing a retransmission packet transmission processing algorithm (N_Channel Stop and Wait) according to the second embodiment of the present invention following FIG. 15A.
[図 16]従来のパケット再送例を示す図である。  FIG. 16 is a diagram illustrating a conventional packet retransmission example.
[図 17]従来のパケット再送例を示す図である。  FIG. 17 is a diagram showing a conventional packet retransmission example.
[図 18]従来のパケット再送例を示す図である。  FIG. 18 is a diagram illustrating a conventional packet retransmission example.
[図 19]従来のパケット再送例を示す図である。  FIG. 19 is a diagram illustrating a conventional packet retransmission example.
[図 20]従来例のパケット再送例（N— Channel Stop and Wait)を示す図である。 符号の説明  FIG. 20 is a diagram showing a conventional packet retransmission example (N—Channel Stop and Wait). Explanation of symbols
[0017] A…基地局は、 1…送信データ制御部、 3…データ処理部、 5…バッファ、 7…パイ ロット生成部、 11…送信データ容量算出部、 15— MCS割り当て部、 17…制御情報 処理部、 21…伝搬路情報処理部、 23…上がりリンク受信処理部、 25…無線送信部 、 27…無線受信部、 ATI…アンテナ。  [0017] A ... the base station is: 1 ... transmission data control unit, 3 ... data processing unit, 5 ... buffer, 7 ... pilot generation unit, 11 ... transmission data capacity calculation unit, 15- MCS allocation unit, 17 ... control Information processing unit, 21 ... propagation path information processing unit, 23 ... uplink reception processing unit, 25 ... wireless transmission unit, 27 ... wireless reception unit, ATI ... antenna.
発明を実施するための最良の形態  BEST MODE FOR CARRYING OUT THE INVENTION
[0018] 本明細書は、 2005年 5月 16日に日本国特許庁に出願された特許出願（出願番号[0018] This specification is a patent application filed with the Japan Patent Office on May 16, 2005 (application number
2005— 142227号)を基礎出願とする優先権主張出願であり、基礎出願の内容は、 本願明細書の内容として取り込むことができるものとする。 2005-142227) as a basic application, and the contents of the basic application can be incorporated as the contents of the present specification.
[0019] 本明細書において、新規パケットとは初めて送るパケットであり、再送パケットとは前 に 1回以上送ってレ、るパケットを指す。 In this specification, a new packet is a packet that is sent for the first time, and a retransmission packet is a packet that is sent at least once before.
[0020] 以下に、本発明の第 1の実施の形態による無線通信技術について図面を参照しつ つ説明を行う。図 1、 2は、本発明の形態による無線通信技術に用いられる無線通信 システムのシステム構成例を示す機能ブロック図である。図 1は基地局の構成例を、 図 2は移動局の構成例を示す図である。 [0020] Hereinafter, a wireless communication technique according to a first embodiment of the present invention will be described with reference to the drawings. 1 and 2 show wireless communication used in the wireless communication technology according to the embodiment of the present invention. It is a functional block diagram which shows the system configuration example of a system. FIG. 1 is a diagram illustrating a configuration example of a base station, and FIG. 2 is a diagram illustrating a configuration example of a mobile station.
[0021] 図 1に示すように、基地局 Aは、送信データ制御部 1と、データ処理部 3と、ノくッファ  [0021] As shown in FIG. 1, the base station A includes a transmission data control unit 1, a data processing unit 3, and a buffer.
5と、パイロット生成部 7と、送信データ容量算出部 11と、 MCS割り当て部 15と、制御 情報処理部 17と、伝搬路情報処理部 21と、上がりリンク受信処理部 23と、無線送信 部 25と、無線受信部 27と、アンテナ ATIと、を有している。  5, a pilot generation unit 7, a transmission data capacity calculation unit 11, an MCS allocation unit 15, a control information processing unit 17, a propagation path information processing unit 21, an uplink reception processing unit 23, and a radio transmission unit 25 And a radio receiver 27 and an antenna ATI.
[0022] 図 1に示す構成を有する基地局 Aにおレ、ては、新規送信データは送信データ制御 部 1に入力される。送信データ制御部 1は、送信データ容量算出部 11から指示され る送信データ容量と、制御情報処理部 17からの以前送信したパケットの Ack/Nac k情報力も新規パケットと再送パケットとを送信するか否力、を判定し、新規パケットを送 信する場合に新規送信データをパケット化し、データ処理部 3に送る。そして、バケツ ト化されたデータを、再送処理の為にバッファ 5に一旦保存する。再送パケットを送信 する場合には、送信データ制御部 1がバッファ 5に保存されている再送データを抽出 し、データ処理部 3に送る。  New transmission data is input to transmission data control section 1 at base station A having the configuration shown in FIG. Whether the transmission data control unit 1 transmits a new packet and a retransmission packet as well as the transmission data capacity instructed by the transmission data capacity calculation unit 11 and the Ack / Nack information power of the previously transmitted packet from the control information processing unit 17. When the new packet is transmitted, the new transmission data is packetized and sent to the data processing unit 3. Then, the bucketed data is temporarily stored in the buffer 5 for retransmission processing. When transmitting a retransmission packet, the transmission data control unit 1 extracts the retransmission data stored in the buffer 5 and sends it to the data processing unit 3.
[0023] また、制御情報処理部 17からの Ack/Nack情報に基づいて、送信に成功したパ ケットのデータをバッファ 5から消去する。データ処理部 3は MCS割当部 5から指示さ れた変調方式'符号化率でデータの変調'符号化を行い、無線送信部 25に渡す。ま た、この時、移動局が無線区間の伝搬路推定を行う為のパイロットデータとデータに 対する変調方式'符号ィヒ率に関する情報をデータに付加する。無線送信部 25では、 データ変調された信号を無線周波数帯にアップコンバートし、各サブキャリアの送信 電力を一定にして移動局に送信する。  Further, based on the Ack / Nack information from the control information processing unit 17, the packet data that has been successfully transmitted is erased from the buffer 5. The data processing unit 3 performs the modulation method “modulation of data with a coding rate” specified by the MCS allocating unit 5 and passes the data to the wireless transmission unit 25. Also, at this time, the mobile station adds pilot data for performing channel estimation in the radio section and information on the modulation scheme for the data, ie, the code ratio. The radio transmission unit 25 up-converts the data-modulated signal to a radio frequency band, and transmits the signal to the mobile station with the transmission power of each subcarrier constant.
[0024] 無線受信部 27では、移動局から送信された無線信号を IF周波数帯にダウンコンパ ートして、上りリンク受信処理部 23に渡す。上りリンク受信処理部 23では、データ変 調された信号を復調し、受信データ、伝搬路推定情報、制御情報に分け、伝搬路推 定情報は伝搬路情報処理部 21へ、制御情報は制御情報処理部 17に送り、受信デ ータは上位層に渡す。伝搬路情報処理部 21は伝搬路推定情報を MCS割当部 15 が行うサブキャリア毎の MCSの決定の為の伝搬路データに変換して MCS割当部 1 5に送る。 MCS割当部 15では伝搬路データからサブキャリア毎に MCSを決定し、決 定された MCSによりデータ処理部 3を制御する。また、決定した MCS情報を送信デ ータ容量算出部 11に送る。送信データ容量算出部 11では、 MCS情報から送信デ ータ容量を算出し、送信データ制御部 1に算出結果を渡す。制御情報処理部 11で は、制御情報の中から送信パケットの Ack/Nack情報を抽出し、送信データ制御部 1に渡す。 [0024] The radio reception unit 27 down-converts the radio signal transmitted from the mobile station to the IF frequency band and passes it to the uplink reception processing unit 23. Uplink reception processing section 23 demodulates the data-modulated signal and divides it into received data, propagation path estimation information, and control information. Propagation path estimation information is transmitted to propagation path information processing section 21, and control information is control information. The data is sent to the processing unit 17, and the received data is passed to the upper layer. The propagation path information processing unit 21 converts the propagation path estimation information into propagation path data for MCS determination for each subcarrier performed by the MCS allocation unit 15 and sends it to the MCS allocation unit 15. The MCS allocator 15 determines the MCS for each subcarrier from the propagation path data, and determines it. Data processor 3 is controlled by the specified MCS. Also, the determined MCS information is sent to the transmission data capacity calculation unit 11. The transmission data capacity calculation unit 11 calculates the transmission data capacity from the MCS information and passes the calculation result to the transmission data control unit 1. The control information processing unit 11 extracts the Ack / Nack information of the transmission packet from the control information and passes it to the transmission data control unit 1.
[0025] ここで、送信データ処理部 3について図 13を参照しつつ詳細に説明する。図 1及び 図 13に示すように、本実施の形態による送信データ処理部 3は、パケット処理部 3_ 1と、再パケット化部 3 _ 2と、新規/再送パケット判定部 3_ 3と、パケット管理部 3 _ 4と、を有している。図 13に示すパケット管理部 3— 4は、制御情報処理部 17からの A ck/Nack情報を元に再送パケットの有/無、再送パケットのパケット番号、データサ ィズを、新規/再送パケット判定部 3— 3に通知する。また、バッファ 5から送信成功 のパケットのデータを消去する力 \再送パケットのデータサイズを調べる。新規 Z再 送パケット判定部 3— 3は、パケット管理部 3— 4からの再送パケット情報と送信データ 容量算出部 11からのデータサイズ情報から新規パケットを送信するか再送パケットを 送信するかに関する判定を行う。  Here, the transmission data processing unit 3 will be described in detail with reference to FIG. As shown in FIG. 1 and FIG. 13, the transmission data processing unit 3 according to the present embodiment includes a packet processing unit 3_1, a repacketizing unit 3_2, a new / retransmission packet determining unit 3_3, and a packet management unit. Part 3_4. The packet management unit 3-4 shown in FIG. 13 determines the presence / absence of the retransmission packet, the packet number of the retransmission packet, and the data size based on the Ack / Nack information from the control information processing unit 17, and determines whether the packet is a new / retransmitted packet. Notify Part 3—3. Also, the ability to erase the data of successfully transmitted packets from buffer 5 \ Check the data size of retransmitted packets. The new Z retransmission packet determination unit 3-3 determines whether to transmit a new packet or a retransmission packet from the retransmission packet information from the packet management unit 3-4 and the data size information from the transmission data capacity calculation unit 11. I do.
[0026] 新規パケットを送信する場合は、パケット化部 3— 1にデータサイズ情報を送り、新 規データをパケット化するように指示をする。再送パケットを送信する場合は、バッフ ァ 5から再送パケットデータを送出するように指示する。パケット化部 3—1は、新規/ 再送パケット判定部 3— 3からの指示により新規データのパケットィ匕を行レ、、データ処 理部に送る。また、パケット化したデータをバッファ 6に保存する。再パケット化部 3— 2は、バッファからの再送パケットデータを再パケットィ匕し、データ処理部 3に送る。  [0026] When a new packet is transmitted, data size information is sent to the packetizing unit 3-1, and an instruction is given to packetize the new data. When sending a retransmission packet, the buffer 5 is instructed to send retransmission packet data. The packetizing unit 3-1 sends a packet of new data to the data processing unit in response to an instruction from the new / retransmitted packet determining unit 3-3. The packetized data is stored in the buffer 6. The repacketizing unit 3-2 repackets the retransmitted packet data from the buffer and sends it to the data processing unit 3.
[0027] 図 2は、移動局の構成例を示す機能ブロック図である。図 2に示すように、本実施の 形態による無線通信システムにおける移動局 Bは、基地局からの信号を受信するァ ンテナ AT2と、無線受信部 31と、制御情報'データ分離部 33と、データ処理部 35と 、 MCS制御部 37と、パケット判定部 41と、伝搬路情報作成部 45と、無線送信部 48 と、上りリンク送信処理部 47と、を有している。  FIG. 2 is a functional block diagram showing a configuration example of the mobile station. As shown in FIG. 2, mobile station B in the radio communication system according to the present embodiment has antenna AT2, which receives a signal from the base station, radio reception unit 31, control information 'data separation unit 33, data The processing unit 35, the MCS control unit 37, the packet determination unit 41, the propagation path information creation unit 45, the radio transmission unit 48, and the uplink transmission processing unit 47 are included.
[0028] 無線受信部 31で、基地局 (A)からの無線信号を受信し、無線周波数帯の無線信 号を IF周波数帯にダウンコンバートし、データ変調された信号を制御情報 ·データ分 離部 33に送る。制御情報 ·データ分離部 33では、データ部と制御情報とに分離し、 データ部はデータ処理部 35に送り、制御情報の変調方式 ·符号化率の情報は MCS 制御部 37に送り、パイロットデータは伝搬路情報作成部 45に送る。データ処理部 35 では、 MCS制御部 37からの指示に従って復調処理を行いパケットデータに戻し、パ ケット判定部 41に渡す。パケット判定部 41は、受信したパケットが正しいか否力、を判 定し、成否情報を上りリンク送信処理部 47に送る。受信したパケットが正しい場合は 、上位層にデータを送る。受信パケットが正しくない場合は、パケットを破棄するか、 または、再送パケットとの合成を行うためにバッファ 5 (図 1)に保存しておく。 [0028] Radio receiver 31 receives a radio signal from base station (A), down-converts the radio signal in the radio frequency band to IF frequency band, and converts the data-modulated signal into control information / data Send to remote part 33. The control information / data separation unit 33 separates the data part and the control information, sends the data part to the data processing part 35, and sends the modulation method / coding rate information of the control information to the MCS control part 37 to obtain pilot data. Is sent to the propagation path information creation unit 45. The data processing unit 35 performs demodulation processing according to an instruction from the MCS control unit 37, returns the packet data, and passes the packet data to the packet determination unit 41. The packet determination unit 41 determines whether or not the received packet is correct, and sends success / failure information to the uplink transmission processing unit 47. If the received packet is correct, the data is sent to the upper layer. If the received packet is not correct, discard the packet or save it in buffer 5 (Figure 1) for synthesis with the retransmitted packet.
[0029] 伝搬路情報作成部 45では、パイロットデータから基地局、移動局間の伝搬路を推 定し、伝搬路推定結果を上りリンク送信処理部 47に送る。上りリンク送信処理部 47で は、送信データに対して伝搬路推定結果と受信パケットの Ack/Nack情報を付加し てデータ変調を行い、無線送信部 48に渡す。ここで、データ変調された信号を無線 周波数帯にアップコンバートして基地局に送る。尚、基地局受信側および移動局送 信側の上りリンクの通信制御に関しては、適応変調制御を用レ、なくてもょレ、。  [0029] The propagation path information creation unit 45 estimates the propagation path between the base station and the mobile station from the pilot data, and sends the propagation path estimation result to the uplink transmission processing unit 47. The uplink transmission processing unit 47 adds the propagation path estimation result and the Ack / Nack information of the received packet to the transmission data, modulates the data, and passes it to the wireless transmission unit 48. Here, the data-modulated signal is up-converted to a radio frequency band and sent to the base station. For uplink communication control on the base station receiving side and mobile station transmitting side, adaptive modulation control is not necessary.
[0030] 図 3は、基地局から移動局に対して送信されるパケットフレームの構成例を示す図 である。図 3に示すように、パケットフレーム 50の先頭には、移動局が伝搬路推定を 行う為のパイロット信号 51が配置され、次にサブキャリア毎の変調方式'符号化率情 報 53が配置され、新規/再送パケットを判定するパケット判定フラグ 55が配置され、 次いで、パケット番号 57、データ 58aの順に配置される。再送パケットにおいて、複数 パケットを組み合わせて送信する場合は、パケット番号 59とデータ 58bとが更に続い て配置される。  FIG. 3 is a diagram showing a configuration example of a packet frame transmitted from the base station to the mobile station. As shown in FIG. 3, a pilot signal 51 for the mobile station to perform channel estimation is arranged at the head of the packet frame 50, and then a modulation scheme for each subcarrier 'coding rate information 53 is arranged. Then, a packet determination flag 55 for determining a new / retransmission packet is arranged, and then the packet number 57 and data 58a are arranged in this order. When retransmitted packets are combined and transmitted, packet number 59 and data 58b are further arranged.
[0031] 図 4は、移動局から基地局に対して送信されるパケットフレームの構成例を示す図 である。図 4に示すように、パケットフレーム 60の先頭には、移動局が推定した伝搬 路推定情報 61が配置され、次に、 AckZNack情報 63、データ 65が順に配置され て構成される。尚、 Ack、 Nackの判定は、移動局からの通知による判定方法の他に 、タイマー処理によっても判定することもできる。タイマー処理による方法は、ある時間 を経過しても Ackが返らなレ、場合には、 Nackであると判定する方法を含む。  FIG. 4 is a diagram showing a configuration example of a packet frame transmitted from the mobile station to the base station. As shown in FIG. 4, propagation path estimation information 61 estimated by the mobile station is arranged at the head of the packet frame 60, and then AckZNack information 63 and data 65 are arranged in order. Ack and Nack can be determined not only by a determination method based on notification from the mobile station but also by timer processing. The method using the timer process includes a method of determining that the Ack is not returned even if a certain period of time has elapsed, and that it is a Nack.
[0032] 次に、再送パケットの送信処理アルゴリズムを以下に説明する。図 5は、再送バケツ トの送信処理のアルゴリズムを示すフローチャート図である。再送パケットの送信処理 アルゴリズム S1においては、まず、ステップ S2において、移動局からの通知された A ck/Nack情報から、再送するパケットがあるか否力を確認する。再送するパケットが ある場合は (Yes)、ステップ S6に進み、移動局から通知される伝搬路情報からサブ キャリア毎の変調方式 ·符号化率を算出する。次いで、ステップ S7において、ステツ プ S6で算出されたサブキャリア毎の変調方式 ·符号ィ匕率から送信パケットの送信ビッ ト容量を算出する。ステップ S8において、算出された送信ビット容量と再送パケット容 量とを比較する。算出された送信ビット容量と再送パケット容量とを比較した結果、再 送パケット容量が (送信ビット容量≥再送パケット容量≥送信ビット容量— α )の関係 にある場合 (Yes)、再送パケットを送信に適していると判断して、ステップ S9におい てパケット識別フラグに 1をセットして再送パケットを送信する。送信パケット容量と再 送パケット容量の比較は、全ての再送すべきパケットに対して行レ、、パケット番号が 小さいパケットを優先して送信する。再送パケット容量が（送信ビット容量≥再送パケ ット容量≥送信ビット容量— α )の関係にない場合 (No)、ステップ S10に進み、算出 された送信ビット容量と再送パケット群容量と比較する (複数の再送パケットがある場 合)。ステップ S10の比較の結果、再送パケット容量が（送信ビット容量≥再送バケツ ト群容量≥送信ビット容量 α )の関係にある場合 (Yes)、再送パケットを送信に適 していると判断して、ステップ S12に進み、パケット識別フラグに 1をセットして再送パ ケット群を送信する。以上の場合以外は、再送パケットの送信に適さないと判断して（ No)、ステップ S11に進み、新規データを算出された送信パケット容量になるようにパ ケット化し、パケット識別フラグに 0をセットして新規パケットを送信する。 [0032] Next, a retransmission packet transmission processing algorithm will be described below. Figure 5 shows the retransmission bucket. It is a flowchart figure which shows the algorithm of the transmission process of G. Retransmission packet transmission processing In algorithm S1, first, in step S2, whether or not there is a packet to be retransmitted is confirmed from the Ack / Nack information notified from the mobile station. If there is a packet to be retransmitted (Yes), the process proceeds to step S6, and the modulation scheme / coding rate for each subcarrier is calculated from the propagation path information notified from the mobile station. Next, in step S7, the transmission bit capacity of the transmission packet is calculated from the modulation scheme / code rate for each subcarrier calculated in step S6. In step S8, the calculated transmission bit capacity is compared with the retransmission packet capacity. As a result of comparing the calculated transmission bit capacity with the retransmission packet capacity, if the retransmission packet capacity has a relationship of (transmission bit capacity ≥ retransmission packet capacity ≥ transmission bit capacity-α) (Yes), the retransmission packet is transmitted. In step S9, the packet identification flag is set to 1 and a retransmission packet is transmitted. For comparison between the capacity of the transmitted packet and the capacity of the retransmitted packet, all packets to be retransmitted are prioritized and packets with smaller packet numbers are transmitted. If the retransmission packet capacity is not in the relationship of (transmission bit capacity ≥ retransmission packet capacity ≥ transmission bit capacity-α) (No), proceed to step S10 and compare the calculated transmission bit capacity with the retransmission packet group capacity ( (If there are multiple retransmission packets). As a result of the comparison in step S10, if the retransmission packet capacity is in the relationship of (transmission bit capacity ≥ retransmission packet group capacity ≥ transmission bit capacity α ) (Yes), it is determined that the retransmission packet is suitable for transmission. Proceeding to step S12, the packet identification flag is set to 1 and a retransmission packet group is transmitted. In cases other than the above, it is determined that the packet is not suitable for retransmission packet transmission (No), and the process proceeds to step S11 where new data is packetized to the calculated transmission packet capacity and the packet identification flag is set to 0. To send a new packet.
[0033] 以上の処理を再送パケットが存在する間繰り返す。ステップ S2において再送バケツ トがないと判断された場合 (No)は、ステップ S3、 S4に進み、算出されたサブキャリア 毎の変調方式'符号ィ匕率力も送信パケットの送信ビット容量を算出する。新規データ を算出された送信パケット容量になるようにパケットィ匕し、パケット識別フラグに 0をセ ットして新規パケットを送信する（ステップ S5)。ステップ S9、 S12、 S5から終了（ステ ップ S 13)に進む。 [0033] The above processing is repeated while there are retransmission packets. If it is determined in step S2 that there is no retransmission bucket (No), the process proceeds to steps S3 and S4, and the modulation scheme for each subcarrier 'code rate factor also calculates the transmission bit capacity of the transmission packet. The new data is packetized so as to have the calculated transmission packet capacity, the packet identification flag is set to 0, and a new packet is transmitted (step S5). Proceed from step S9, S12, S5 to end (step S13).
[0034] 次に、具体的な例について図 7から図 9までを参照しつつ説明する。ここでは、 100 本のサブキャリアを 1ブロックとして適応変調している場合を例にして説明する。 Next, a specific example will be described with reference to FIGS. Here, 100 An example in which adaptive modulation is performed with one subcarrier as one block will be described.
[0035] 図 7に示すように、基地局からパケット 1が QPSK分（200bit)で送信され、移動局 で受信失敗の判定がなされると、移動局は基地局に対して Nack情報を通知する。 パケット 1の Nack情報を受け取った基地局は、パケット 1が再送パケットとして存在す るため、移動局からの伝搬路推定情報からサブキャリア毎の変調方式 ·符号化率を 算出し、算出された変調方式符号化率から次に送信するパケットの送信ビット容量を 算出する。パケット 3送信後に再送パケット 1を送信するか否力、を判定する。この時、 送信パケットの送信ビット容量が BPSK分（lOObit)であるため、パケット 3の送信後 には新規パケット 4を送信するものと判断してパケット 4を送信する。  [0035] As shown in FIG. 7, when the base station transmits packet 1 for QPSK (200 bits) and the mobile station determines that reception has failed, the mobile station notifies the base station of Nack information. . The base station that received the Nack information of packet 1 calculates the modulation method and coding rate for each subcarrier from the propagation path estimation information from the mobile station because packet 1 exists as a retransmission packet. The transmission bit capacity of the next packet to be transmitted is calculated from the system coding rate. Determines whether or not to send retransmission packet 1 after packet 3 transmission. At this time, since the transmission bit capacity of the transmission packet is BPSK (lOObit), after transmission of packet 3, it is determined that new packet 4 is to be transmitted, and packet 4 is transmitted.
[0036] 次に、同様にして送信ビット容量を算出し、パケット 4の送信後に再送パケット 1を送 信するか否かを判定する。送信パケットの送信ビット容量が QPSK分（200bit)であ るため、パケット 4の送信後には再送パケット 1を送信することができると判断して実際 に再送パケット 1 (QPSK, 200ビット）を移動局に対して送信する。  Next, the transmission bit capacity is calculated in the same manner, and it is determined whether or not retransmission packet 1 is transmitted after packet 4 is transmitted. Since the transmission bit capacity of the transmission packet is QPSK (200 bits), it is determined that retransmission packet 1 can be transmitted after packet 4 is transmitted, and retransmission packet 1 (QPSK, 200 bits) is actually transmitted to the mobile station. Send to.
[0037] このように、各送信機会において送信ビットの容量と再送パケットの容量とに基づい て、再送パケットを送るか新規パケットを送るかを判断することができる。  In this way, it is possible to determine whether to send a retransmission packet or a new packet based on the transmission bit capacity and the retransmission packet capacity at each transmission opportunity.
[0038] 次に、図 8を参照しつつ、パケット再送例について説明する。図 8に示すように、ま ず、基地局からパケット 1が QPSK分（200bit)で送信され、移動局で受信失敗の判 定がされると、移動局は基地局に Nack情報を通知する。パケット 1の Nack情報を受 け取った基地局は、パケット 1が再送パケットとして存在するため、移動局からの伝搬 路推定情報からサブキャリア毎の変調方式 '符号化率を算出し、算出された変調方 式符号化率に基づいて、次に送信するパケットの送信ビット容量を算出する。バケツ ト 3を送信した後に、再送パケット 1を送信するか否かについて判定する。この時の送 信パケットの送信ビット容量が BPSK分 (400bit)であるため、パケット 3の送信後に は新規パケット 4を送信すると判断して新規パケット 4を送信する。  Next, an example of packet retransmission will be described with reference to FIG. As shown in Fig. 8, first, when the base station transmits packet 1 for QPSK (200 bits) and the mobile station determines that reception has failed, the mobile station notifies the base station of Nack information. The base station that has received the Nack information of packet 1 calculates the modulation rate for each subcarrier from the propagation path estimation information from the mobile station because the packet 1 exists as a retransmission packet. Based on the modulation scheme coding rate, the transmission bit capacity of the packet to be transmitted next is calculated. After sending bucket 3, determine whether to send resend packet 1 or not. Since the transmission bit capacity of the transmission packet at this time is BPSK (400 bits), after packet 3 is transmitted, it is determined that new packet 4 is to be transmitted, and new packet 4 is transmitted.
[0039] 次に、同様にして送信ビット容量を算出し、パケット 4の送信後に、再送パケット 1を 送信するか否かを判定する。この場合には、送信パケットの送信ビット容量が QPSK 分（200bit)であるため、新規パケット 4の送信後には再送パケット 1を送信すると判 断して再送パケット 4を送信する。 [0040] 次に、図 9を参照しつつ、別のパケット送信例について説明を行う。図 9に示すよう に、基地局からパケット 1が QPSK分（200bit)で送信され、移動局で受信失敗の判 定がされ、移動局は基地局に Nack情報を通知する。パケット 1の Nack情報を受け 取った基地局は、パケット 1が再送パケットとして存在するため、移動局からの伝搬路 推定情報からサブキャリア毎の変調方式'符号化率を算出し、算出された変調方式 符号化率から次に送信するパケットの送信ビット容量を算出する。パケット 3を送信し た後に再送パケット 1を送信するか否力 ^判定する。この時の送信パケットの送信ビッ ト容量が 16QAM分 (400bit)であるため、パケット 3の送信後には新規パケット 4を 送信すると判断して新規パケット 4を送信する。新規パケット 4送信時に、同様にパケ ット 2についても Nack情報を受信したとする。この場合にも、同様にして送信ビット容 量を算出し、新規パケット 4の送信後に、再送パケット 1と再送パケット 2とのいずれを 送信するかについて判定を行う。送信パケットの送信ビット容量が 16QAM分 (400b it)であるため、再送パケット 1のみ又は再送パケット 2のみの送信では余力がありす ぎるため、再度、再送パケット 1及び再送パケット 2を送信するか否かについて判定す る。送信パケットの送信ビット容量が 16QAM分（400bit)であるため、パケット 1、パ ケット 2を組み合わせて送信が可能であると判断されるため、新規パケット 4の送信後 には、再送パケット 1と再送パケット 2とを送信すると判断し、実際に 1回の送信で再送 パケット 1と再送パケット 2とを送信することができる。このように、 1回のパケット送信で 複数の再送パケットを送信することも通信路の状況次第では判断における選択肢と なる。 Next, the transmission bit capacity is calculated in the same manner, and it is determined whether or not retransmission packet 1 is transmitted after packet 4 is transmitted. In this case, since the transmission bit capacity of the transmission packet is QPSK (200 bits), it is determined that retransmission packet 1 is transmitted after transmission of new packet 4, and retransmission packet 4 is transmitted. [0040] Next, another example of packet transmission will be described with reference to FIG. As shown in Fig. 9, packet 1 is transmitted from the base station for QPSK (200 bits), the mobile station determines that reception has failed, and the mobile station notifies the base station of Nack information. The base station that has received the Nack information of packet 1 calculates the modulation method 'coding rate for each subcarrier from the propagation path estimation information from the mobile station because packet 1 exists as a retransmission packet, and calculates the calculated modulation. Method The transmission bit capacity of the next packet to be transmitted is calculated from the coding rate. Determine whether or not to send resend packet 1 after sending packet 3. Since the transmission bit capacity of the transmission packet at this time is 16QAM (400 bits), it is determined that new packet 4 will be transmitted after packet 3 is transmitted, and new packet 4 is transmitted. Similarly, assume that Nack information is received for packet 2 when new packet 4 is transmitted. In this case as well, the transmission bit capacity is calculated in the same manner, and it is determined whether the retransmission packet 1 or the retransmission packet 2 is transmitted after the new packet 4 is transmitted. Since the transmission bit capacity of the transmission packet is 16QAM (400 bits), there is not enough room to transmit only retransmission packet 1 or retransmission packet 2, so whether retransmission packet 1 and retransmission packet 2 are transmitted again. Judge about. Since the transmission bit capacity of the transmission packet is 16QAM (400 bits), it is judged that transmission is possible by combining packet 1 and packet 2. Therefore, after transmission of new packet 4, retransmission packet 1 and retransmission It is determined that packet 2 is to be transmitted, and retransmission packet 1 and retransmission packet 2 can be actually transmitted in one transmission. In this way, sending a plurality of retransmitted packets in one packet transmission is also an option for judgment depending on the condition of the communication path.
[0041] 上述の図 5に示したアルゴリズムでは、再送遅延を考慮していなかった。そこで、再 送パケットの判定処理を N回に制限した場合における再送処理遅延を考慮した再送 パケットの送信処理アルゴリズムについて図 6A、図 6Bを参照しつつ説明を行う。  [0041] In the algorithm shown in Fig. 5 described above, retransmission delay is not considered. Therefore, the retransmission packet transmission processing algorithm considering the retransmission processing delay when the retransmission packet determination processing is limited to N times will be described with reference to FIGS. 6A and 6B.
[0042] 図 6A， Bに示すように、再送パケット送信アルゴリズム S21では、まず、ステップ S2 2において、移動局からの通知された AckZNack情報から再送するパケットがある か否かを確認する。ステップ S22において再送するパケットがある場合は (Yes)は、 ステップ S26に進み、判定回数 N= lとする。次いで、ステップ S27に進み、移動局 から通知される伝搬路情報からサブキャリア毎の変調方式 ·符号化率を算出する。次 いで、ステップ S28に進み、算出されたサブキャリア毎の変調方式 ·符号化率から送 信パケットの送信ビット容量 (データサイス）を算出する。次に、ステップ S29において 、再送パケットの判定回数 Nをチェックする。判定回数 Nが繰り返し回数 X以上の場 合は（No)、ステップ S32に進みパケット識別フラグに 1をセットして再送パケットを送 信する。 1回で送信できない場合は、パケットを分割して送るか、又は、初回の変調方 式'符号化率で送信するなどの 1回で送信する方法をとる。 [0042] As shown in FIGS. 6A and 6B, in retransmission packet transmission algorithm S21, first, in step S22, it is confirmed whether there is a packet to be retransmitted from the AckZNack information notified from the mobile station. If there is a packet to be retransmitted in step S22 (Yes), the process proceeds to step S26, where the number of determinations is N = 1. Next, the process proceeds to step S27, where the modulation scheme / coding rate for each subcarrier is calculated from the propagation path information notified from the mobile station. Next In step S28, the transmission bit capacity (data size) of the transmission packet is calculated from the calculated modulation scheme and coding rate for each subcarrier. Next, in step S29, the number N of retransmission packet determinations is checked. If the number of determinations N is greater than or equal to the number of repetitions X (No), go to step S32 and set the packet identification flag to 1 and send a retransmission packet. If transmission is not possible at one time, the packet is divided and sent, or the first modulation method is used, such as transmission at the coding rate.
[0043] ステップ S29の判定にぉレ、て、判定回数 Nが繰り返し回数 X未満の場合は (Yes)、 ステップ S30に進み、算出された送信ビット容量と再送パケット容量とを比較する。比 較した結果、再送パケット容量が (送信ビット容量≥再送パケット容量≥送信ビット容 量一ひ）の関係にある場合は再送パケットを送信に適していると判断して (Yes)、ス テツプ S31においてパケット識別フラグに 1をセットし、ステップ S32において再送パ ケットを送信する。  If the determination number N is less than the repetition number X (Yes) in step S29, the process proceeds to step S30, and the calculated transmission bit capacity is compared with the retransmission packet capacity. As a result of the comparison, if the retransmission packet capacity is in the relationship of (transmission bit capacity ≥ retransmission packet capacity ≥ transmission bit capacity 1), it is determined that the retransmission packet is suitable for transmission (Yes), and step S31 In step S32, the packet identification flag is set to 1, and a retransmission packet is transmitted in step S32.
[0044] ステップ S30における送信パケット容量と再送パケット容量との比較ステップは、全 ての再送すべきパケットに対して行い、パケット番号が小さいパケットを優先的に送信 する。再送パケット容量が（送信ビット容量≥再送パケット容量≥送信ビット容量 a )の関係にない場合 No)、ステップ S33進み、算出された送信ビット容量と再送バケツ ト群容量とを比較する（複数の再送パケットがある場合)。比較した結果、再送パケット 容量が (送信ビット容量≥再送パケット群容量≥送信ビット容量 α )の関係にある 場合、再送パケットを送信に適していると判断して、ステップ S34に進み (Yes)、パケ ット識別フラグに 1をセットして再送パケット群を送信する。以上の場合以外は、再送 パケットの送信に適さないと判断して、新規データを算出された送信パケット容量に なるようにパケット化し、新規パケットの送出時（S36)パケット識別フラグに 0をセットし て新規パケットを送信する。以上を再送パケットが存在する間は繰り返す。  [0044] The comparison step between the transmission packet capacity and the retransmission packet capacity in step S30 is performed for all the packets to be retransmitted, and a packet with a small packet number is preferentially transmitted. If the retransmission packet capacity is not in the relationship (transmission bit capacity ≥ retransmission packet capacity ≥ transmission bit capacity a) No), proceed to step S33 and compare the calculated transmission bit capacity with the retransmission packet group capacity (multiple retransmission If there are packets). As a result of the comparison, if the retransmission packet capacity is in the relationship of (transmission bit capacity ≥ retransmission packet group capacity ≥ transmission bit capacity α), it is determined that the retransmission packet is suitable for transmission, and the process proceeds to step S34 (Yes), Set the packet identification flag to 1 and send the retransmission packet group. In cases other than the above, it is determined that the packet is not suitable for retransmission packet transmission, and new data is packetized to the calculated transmission packet capacity. When a new packet is sent (S36), the packet identification flag is set to 0. Send a new packet. The above is repeated while the retransmission packet exists.
[0045] ステップ S22において再送パケットがない場合は（No)、ステップ S23に進み、算出 されたサブキャリア毎の変調方式 ·符号化率から送信パケットの送信ビット容量を算 出する。次いで、ステップ S24において新規データを算出された送信パケット容量に なるようにパケット化し、パケット識別フラグに 0をセットしてステップ S25において新規 パケットを送信する。 [0046] 尚、再送パケットの判定処理を N回は、データの Qosを考慮してデータ毎に可変に することも可能である。 [0045] If there is no retransmission packet in step S22 (No), the process proceeds to step S23, and the transmission bit capacity of the transmission packet is calculated from the calculated modulation scheme and coding rate for each subcarrier. Next, in step S24, new data is packetized so as to have the calculated transmission packet capacity, the packet identification flag is set to 0, and a new packet is transmitted in step S25. It should be noted that the retransmission packet determination process can be varied N times for each data in consideration of the data QoS.
[0047] この点について、図 10及び図 11を参照しつつ具体的に説明する。この時の判定 繰り返し回数 Xは 3として説明する。図 10に示すように、基地局からパケット 1が QPS K分（200bit)で送信され、移動局で受信失敗の判定がなされると、移動局は基地局 に対して Nack情報を通知する。パケット 1の Nack情報を受け取った基地局は、パケ ット 1が再送パケットとして存在するので、移動局からの伝搬路推定情報からサブキヤ リア毎の変調方式'符号ィヒ率を算出し、算出された変調方式符号化率から次に送信 するパケットの送信ビット容量を算出する。そして、再送の判定回数が初回（1回目） であるので、パケット 3を送信した後に再送パケット 1を送信するか否力 ^判定する。こ の時の送信パケットの送信ビット容量力 ¾PSK分（lOObit)であるため、パケット 3の 送信後には新規パケット 4を送信するものと判断して実際にパケット 4を送信する。パ ケット 4の送信後に、同様にして送信ビット容量を算出し、再送パケット 1を送信するか 否かを判定する。送信パケットの送信ビット容量が QPSK分（200bit)であるため、新 規パケット 4の送信後には、再送パケット 1を送信すると判断して再送パケット 1を送信 する。  This point will be specifically described with reference to FIGS. 10 and 11. In this explanation, the number of repetitions X is 3. As shown in Fig. 10, when the base station transmits packet 1 for QPS K (200 bits) and the mobile station determines that reception has failed, the mobile station notifies the base station of Nack information. The base station that has received the Nack information of packet 1 calculates the modulation scheme for each subcarrier from the propagation path estimation information from the mobile station because packet 1 exists as a retransmission packet. The transmission bit capacity of the next packet to be transmitted is calculated from the modulation scheme coding rate. Since the number of retransmission determinations is the first time (first time), it is determined whether or not retransmission packet 1 is transmitted after packet 3 is transmitted. Since the transmission bit capacity of the transmission packet at this time is ¾ PSK (lOObit), after transmission of packet 3, it is determined that new packet 4 is to be transmitted, and packet 4 is actually transmitted. After transmitting packet 4, calculate the transmission bit capacity in the same way, and determine whether or not to send retransmission packet 1. Since the transmission bit capacity of the transmission packet is QPSK (200 bits), it is determined that retransmission packet 1 will be transmitted after transmission of new packet 4, and retransmission packet 1 is transmitted.
[0048] 次いで、図 11を参照しつつ説明を行う。基地局からパケット 1が QPSK (200bit)で 送信され、移動局で受信失敗の判定がされると、移動局は基地局に対して Nack情 報を通知する。パケット 1の Nack情報を受け取った基地局は、パケット 1が再送パケ ットとして存在するため、移動局からの伝搬路推定情報に基づいてサブキャリア毎の 変調方式'符号化率を算出し、算出された変調方式符号化率から次に送信するパケ ットの送信ビット容量を算出する。そして、再送の判定回数が初回（1回目）であるので 、パケット 3の送信後に再送パケット 1を送信するか否かを判定する。この時の送信パ ケットの送信ビット容量が 16QAM分（400bit)であるため、パケット 3の送信後には 新規パケット 4を送信すると判断し新規パケット 4を送信する。次にパケット 4の送信後 に、同様にして送信ビット容量を算出し、再送パケット 1を送信するか否かを判定する 。送信パケットの送信ビット容量が 16QAM分（400bit)であるため、パケット 4の送信 後には新規パケット 5を送信すると判断して新規パケット 5を送信する。パケット 5の送 信後に、同様にして送信ビット容量を算出する。判定回数が 3回目となり、この時の送 信ビット容量は 16QAM分であるにもかかわらず判定繰り返し回数と一致するため、 再送パケットを送信する。 Next, description will be made with reference to FIG. When the base station transmits packet 1 with QPSK (200 bits) and the mobile station determines that reception has failed, the mobile station notifies the base station of Nack information. The base station that has received the Nack information of packet 1 calculates the modulation method 'coding rate for each subcarrier based on the propagation path estimation information from the mobile station because packet 1 exists as a retransmission packet. The transmission bit capacity of the next packet to be transmitted is calculated from the coded modulation method coding rate. Then, since the number of retransmission determinations is the first time (first time), it is determined whether or not retransmission packet 1 is transmitted after packet 3 is transmitted. Since the transmission bit capacity of the transmission packet at this time is 16QAM (400 bits), it is determined that new packet 4 will be transmitted after packet 3 is transmitted, and new packet 4 is transmitted. Next, after packet 4 is transmitted, the transmission bit capacity is calculated in the same manner, and it is determined whether or not retransmission packet 1 is transmitted. Since the transmission bit capacity of the transmission packet is 16QAM (400 bits), it is determined that new packet 5 will be transmitted after packet 4 is transmitted, and new packet 5 is transmitted. Send packet 5 After transmission, the transmission bit capacity is calculated in the same manner. The number of times of determination is the third time, and since the transmission bit capacity at this time is 16QAM, it matches the number of repetitions of determination, so a retransmission packet is transmitted.
[0049] このように、再送パケットを送信する基準として、判定繰り返し回数を用いても良い。  [0049] As described above, the number of repetitions of determination may be used as a reference for transmitting a retransmission packet.
[0050] 次に、本発明の第 2の実施の形態による再送制御技術について図面を参照しつつ 説明を行う。本実施の形態による再送制御技術は、 N_ Channel Stop and Wai t方式を適用したものである。  Next, a retransmission control technique according to the second embodiment of the present invention will be described with reference to the drawings. The retransmission control technique according to the present embodiment applies the N_Channel Stop and Wait method.
[0051] 図 14は、 N_ Channel Stop and Wait方式における送信データ処理部の構成 例を示す図であり、基地局の送信データ処理部 3の構成について、説明を行う。図 1 4に示すように、送信データ処理部 3は、パケットィヒ部 3 _ 1と、再パケット化部 3 _ 2と 、新規/再送パケット判定部 3 _ 3と、パケット管理部 3 _4と、チャネル制御部 3 _ 5と 、を有している。再パケット化部 3— 2は、バッファ 5と接続されている。  FIG. 14 is a diagram illustrating a configuration example of the transmission data processing unit in the N_Channel Stop and Wait method, and the configuration of the transmission data processing unit 3 of the base station will be described. As shown in FIG. 14, the transmission data processing unit 3 includes a packet reception unit 3 _ 1, a repacketization unit 3 _ 2, a new / retransmission packet determination unit 3 _ 3, a packet management unit 3 _ 4, a channel And a control unit 3_5. The repacketizing unit 3-2 is connected to the buffer 5.
[0052] パケット管理部 3— 4は、制御情報処理部からの Ack/Nack情報に基づいて、再 送パケットの有無と、再送パケットのパケット番号と、データサイズとを、新規/再送パ ケット判定部 3— 3に通知する。また、バッファ 5から送信成功のパケットのデータを消 去するか、再送パケットのデータサイズを調べる。  [0052] Based on the Ack / Nack information from the control information processing unit, the packet management unit 3-4 determines the presence / absence of a retransmission packet, the packet number of the retransmission packet, and the data size, and determines the new / retransmission packet. Notify Part 3—3. Also, erase the data of successfully transmitted packet from buffer 5, or check the data size of the retransmitted packet.
[0053] 新規/再送パケット判定部 3— 3は、パケット管理部 3— 4からの再送パケット情報と 送信データ容量算出部からのデータサイズ情報とに基づいて、新規パケットを送信 するか再送パケットを送信するかについて判定する。  The new / retransmission packet determination unit 3-3 transmits a new packet or determines a retransmission packet based on the retransmission packet information from the packet management unit 3-4 and the data size information from the transmission data capacity calculation unit. Determine whether to send.
[0054] 新規パケットを送信する場合には、パケット化部 3—1にデータサイズ情報を送り、 新規データをパケット化するように指示を行う。再送パケットを送信する場合は、バッ ファ 5から再送パケットデータを送出するように指示する。また、判定結果をチャネル 制御部 3 _ 5に送る。パケットィ匕部 3 _ 1は、新規/再送パケット判定部 3 _ 3からの指 示により新規データのパケットィ匕を行レ、、チャネル制御部 3— 5に送る。また、パケット 化したデータをバッファ 5に保存する。  When a new packet is transmitted, data size information is sent to the packetizing unit 3-1, and an instruction is given to packetize the new data. When sending a retransmission packet, the buffer 5 is instructed to send retransmission packet data. Also, the determination result is sent to the channel control unit 3_5. The packet key unit 3_1 transmits a packet of new data to the channel control unit 3-5 in response to an instruction from the new / retransmission packet determination unit 3_3. The packetized data is stored in buffer 5.
[0055] 再パケット化部 3— 2は、バッファ 5からの再送パケットデータを再パケットィ匕し、チヤ ネル制御部 3— 5に送る。チャネル制御部 3— 5は、パケットィ匕部 3—1からのデータに チャネル情報を付加するとともに、新規 Z再送パケット判定部 3— 3からの情報からチ ャネル入れ替えの制御を行う。 [0055] The repacketizing unit 3-2 repackets the retransmitted packet data from the buffer 5 and sends it to the channel control unit 3-5. The channel control unit 3-5 adds channel information to the data from the packet input unit 3-1, and performs a check based on the information from the new Z retransmission packet determination unit 3-3. Control channel switching.
[0056] 図 15A、図 15Bは、本実施の形態による N— Channel Stop and Wait方式の 再送パケットの送信処理アルゴリズムを示す図である。以下に、再送パケットの送信 処理アルゴリズム（S41 )について説明する。まず、ステップ S42において、移動局か ら通知される Ack/Nack情報から再送するパケットがあるかどうか確認する。ステツ プ S42において、 X— CHで再送する再送パケットがある場合は (Yes)、ステップ S4 6に進み、移動局から通知された X— CHの伝搬路情報から次の X— CHのサブキヤ リア毎の変調方式'符号化率を算出する。ステップ S43において、算出されたサブキ ャリア毎の変調方式'符号化率から、次の X_ CHの送信パケットの送信ビット容量（ データサイズ)を算出する。ステップ S48において、算出された送信ビット容量と再送 パケット容量とを比較する。ステップ S48における比較の結果、再送パケット容量が（ 送信ビット容量≥再送パケット容量≥送信ビット容量一ひ）の関係にある場合は、再 送パケットの送信に適していると判断して (Yes)、パケット識別フラグに 1をセットし、ス テツプ S49において X— CHで再送パケットを送信する。再送パケット容量が（送信ビ ット容量≥再送パケット容量≥送信ビット容量— a )の関係にない場合は (No)、ス テツプ S50に進み、算出されている (X—1 )—CHの送信ビット容量と再送パケット容 量を比較する。比較した結果、再送パケット容量が（(X— 1 )— CHの送信ビット容量 ≥再送パケット容量≥ (X- 1 ) CHの送信ビット容量 α )の関係にある場合は (Υ es)、再送パケットを送信に適していると判断して、パケット識別フラグに 1をセットし、 ステップ S51において (X—1 )—CHのタイミングで再送パケットを送信する。また、ス テツプ S52において、 （X—1 )— CHの新規パケットを X—CHのタイミングで送信でき るよう再パケットィ匕し、 S 53において、 X—CHで (X_ l )—CHの新規パケットを送出 する。  FIGS. 15A and 15B are diagrams showing an N-Channel Stop and Wait method retransmission packet transmission processing algorithm according to the present embodiment. The retransmission packet transmission processing algorithm (S41) will be described below. First, in step S42, it is confirmed whether there is a packet to be retransmitted from the Ack / Nack information notified from the mobile station. In step S42, if there is a retransmitted packet to be retransmitted in X—CH (Yes), the process proceeds to step S46, and the next X—CH subcarrier is determined from the X—CH propagation path information notified from the mobile station. The modulation method 'coding rate is calculated. In step S43, the transmission bit capacity (data size) of the transmission packet of the next X_CH is calculated from the calculated modulation scheme for each subcarrier 'coding rate. In step S48, the calculated transmission bit capacity is compared with the retransmission packet capacity. As a result of the comparison in step S48, if the retransmission packet capacity is in the relationship of (transmission bit capacity ≥ retransmission packet capacity ≥ transmission bit capacity one), it is determined that it is suitable for retransmission packet transmission (Yes), Set the packet identification flag to 1, and in step S49, send the retransmission packet using X-CH. If the retransmission packet capacity is not in the relationship of (transmission bit capacity ≥ retransmission packet capacity ≥ transmission bit capacity—a) (No), go to step S50 and calculate (X-1) —CH transmission Compare bit capacity and retransmission packet capacity. As a result of the comparison, if the retransmission packet capacity is in the relationship of ((X — 1) —CH transmission bit capacity ≥ retransmission packet capacity ≥ (X-1) CH transmission bit capacity α), (再送 es) Is determined to be suitable for transmission, the packet identification flag is set to 1, and a retransmission packet is transmitted at the timing (X−1) —CH in step S51. In step S52, the new packet of (X-1) -CH is re-packeted so that it can be transmitted at the timing of X-CH. In S53, the new packet of (X_l) -CH is transmitted with X-CH. Is sent out.
[0057] (X- 1 ) _ CHの送信ビット容量≥再送パケット容量≥ (X- 1 ) _ CHの送信ビット 容量—ひ）の関係にない場合は（No)、ステップ S 54に進み、（X— 1 )— CHで (X— 1 )—CHの新規パケットを送信する。次いで、ステップ S55において、伝搬路情報か ら (X+ 1 ) _ CHで送信する送信ビット容量を算出し、ステップ S56においてサブキヤ リア毎の変調 ·符号ィ匕方式力も送信パケットのデータサイズを算出する。次いで、ステ ップ S57において、 (X+ l)—CHの送信ビット容量と再送パケット容量を比較する。 比較した結果、再送パケット容量が（(X+ l)—CHの送信ビット容量≥再送パケット 容量≥ (X+ l)—CHの送信ビット容量 α )の関係にある場合は、ステップ S58に 進み、（X+ 1) _CHの新規パケットを再パケット化し、 （X+ 1) _CHのタイミングで 再送パケットを送信に適していると判断して、 X—CHのタイミングで (X+ l)—CHの 新規パケットを送信し (ステップ S59)、 (X+ l)—CHのタイミングで X— CHの再送パ ケットを送信する（ステップ S60)。 [0057] If (X- 1) _ CH transmission bit capacity ≥ retransmission packet capacity ≥ (X- 1) _ CH transmission bit capacity—e) (No), go to step S 54 ( X—1) —CH sends a new packet of (X—1) —CH. Next, in step S55, the transmission bit capacity to be transmitted by (X + 1) _CH is calculated from the propagation path information, and in step S56, the data size of the transmission packet is also calculated by the modulation / coding scheme power for each subcarrier. Then step In step S57, the transmission bit capacity of (X + l) —CH is compared with the retransmission packet capacity. As a result of the comparison, if the retransmission packet capacity has a relationship of ((X + l) —CH transmission bit capacity ≥Retransmission packet capacity ≥ (X + l) —CH transmission bit capacity α), the process proceeds to step S58, and (X + 1) Re-packetize the new packet of _CH, determine that it is suitable for sending the retransmit packet at the timing of (X + 1) _CH, and send the new packet of (X + l) -CH at the timing of X-CH. (Step S59), (X + l) —The retransmission packet of X—CH is transmitted at the timing of CH (step S60).
[0058] 以上の場合以外は、再送パケットの送信に適さないと判断して（No)、ステップ S61 において X— CHでは X— CHの新規パケットを送出し、ステップ S62において、（X + 1)—CHでは (X+ l)—CHの新規パケットを送出する。  [0058] Except for the above cases, it is determined that the packet is not suitable for transmission of a retransmission packet (No), and in step S61, X-CH transmits a new packet of X-CH. In step S62, (X + 1) —CH (X + l) —Sends a new CH packet.
[0059] ステップ S42において再送パケットがない場合は（No)、ステップ S43において算出 されたサブキャリア毎の変調方式 ·符号化率から送信パケットの送信ビット容量を算 出する。ステップ S44において、新規データを算出された送信パケット容量になるよう にパケット化し、パケット識別フラグに 0をセットしてステップ S45において X—CHで 新規パケットを送信する。  [0059] If there is no retransmission packet in step S42 (No), the transmission bit capacity of the transmission packet is calculated from the modulation scheme and coding rate for each subcarrier calculated in step S43. In step S44, new data is packetized so as to have the calculated transmission packet capacity, the packet identification flag is set to 0, and in step S45, a new packet is transmitted by X-CH.
[0060] 以下に、図 12を参照しつつ、具体的に説明を行う。まず基地局力 パケット 1 (CH 1)が QPSK分（200bit)で送信され、移動局において受信失敗の判定がされると、 移動局は基地局に対して Nack情報 (伝搬路推定情報も含む）を通知する。パケット 3 (CH3)送信時にパケット 1 (CH1)の Nack情報を受け取った基地局は、パケット 1 (C HI)が再送パケットとして存在するため、移動局からの伝搬路推定情報からサブキヤ リア毎の変調方式'符号化率を算出し、算出された変調方式符号化率から CH1で送 信するパケットの送信ビット容量を算出する。 CH1の送信ビット容量は BPSK (100bi t)と算出され、再送パケット 1を送信することはできない。次に、算出されている CH4 の送信ビット容量と再送パケットの容量とを比較する。  [0060] Hereinafter, a specific description will be given with reference to FIG. First, base station power packet 1 (CH 1) is transmitted in QPSK (200 bits), and when the mobile station determines that reception has failed, the mobile station sends Nack information (including propagation path estimation information) to the base station. To be notified. The base station that received the Nack information of packet 1 (CH1) at the time of packet 3 (CH3) transmission has packet 1 (CHI) as a retransmitted packet, so modulation for each subcarrier is determined from the channel estimation information from the mobile station. System 'coding rate is calculated, and the transmission bit capacity of the packet transmitted on CH1 is calculated from the calculated modulation method coding rate. The transmission bit capacity of CH1 is calculated as BPSK (100bit), and retransmission packet 1 cannot be transmitted. Next, the calculated CH4 transmission bit capacity is compared with the retransmission packet capacity.
[0061] CH4の送信ビット容量は BPSK (lOObit)であるため、再送パケットは送信できず、 新規パケット 4を送信する。新規パケット 4の送信時にパケット 2 (CH2)の ACK情報 を受信し、伝搬路推定情報から次の CH2での送信ビット容量を算出し、 CH2の送信 容量と再送パケット容量とを比較し、この際、 CH2の送信容量は QPSK分（200bit) であるため、再送パケットは CH2のタイミングで送信することができると判断され、 CH 1と CH2とを入れ替えて移動局に送信する。このようにチャネルを入れ替えて送信を 行うことも可能である。 [0061] Since the transmission bit capacity of CH4 is BPSK (lOObit), a retransmission packet cannot be transmitted, and a new packet 4 is transmitted. ACK information of packet 2 (CH2) is received when new packet 4 is transmitted, the transmission bit capacity in the next CH2 is calculated from the propagation path estimation information, and the transmission capacity of CH2 is compared with the retransmission packet capacity. The transmission capacity of CH2 is QPSK (200bit) Therefore, it is determined that the retransmission packet can be transmitted at the timing of CH2, and CH1 and CH2 are exchanged and transmitted to the mobile station. In this way, it is also possible to perform transmission by switching channels.
[0062] H—ARQのような初回パケットと再送パケットとをパケット合成してパケットの信頼性 を高める再送方法では、パケット合成する為、若干、再送パケットの信頼性を低くして も良い。送信パケット容量を増やし、 1回の送信で再送を終えることが望ましぐ再送 パケットに利用する変調方式'符号化率を決定する閾値を低く設定して送信パケット 容量を増やすことも出来る。  [0062] In the retransmission method in which the initial packet and the retransmission packet, such as H-ARQ, are combined to increase the reliability of the packet, the reliability of the retransmission packet may be slightly lowered because the packet is combined. It is also possible to increase the transmission packet capacity by increasing the transmission packet capacity and setting a low threshold value for determining the modulation method used for the retransmitted packet that is desired to be completed after one transmission.
[0063] 以上に説明したように、本発明実施の形態によるパケット再送技術によれば、送信 ビット容量を算出して、送信容量から新規パケットと再送パケットとのいずれを送信す るかを判定する再送判定処理を、送信ビット容量が許容範囲内でできるだけ大きくな る方向になる基準で行うことにより、伝送効率を良くすることができるという利点がある 。さらに、効率良く再送制御を行うことにより、再送遅延を低減できるという利点がある  [0063] As described above, according to the packet retransmission technique according to the embodiment of the present invention, the transmission bit capacity is calculated, and it is determined whether to transmit a new packet or a retransmission packet from the transmission capacity. There is an advantage that transmission efficiency can be improved by performing the retransmission determination process on the basis of the direction in which the transmission bit capacity becomes as large as possible within the allowable range. Furthermore, there is an advantage that retransmission delay can be reduced by performing retransmission control efficiently.
[0064] 尚、サブキャリア毎の無線パラメータの適応制御を行うパケット無線通信システムの 代わりに、複数のサブキャリアを 1つのブロックにまとめてブロック毎に無線パラメータ の適応制御を行うパケット無線通信システムに対しても本実施の形態による技術を適 用することも可能である。この場合は、 1つのブロックを上記サブキャリアと同等に考え て本技術を適用すれば良い。 [0064] Instead of a packet radio communication system that performs adaptive control of radio parameters for each subcarrier, a packet radio communication system that performs adaptive control of radio parameters for each block by combining a plurality of subcarriers into one block. The technique according to the present embodiment can also be applied to this. In this case, the present technology may be applied by considering one block as equivalent to the subcarrier.
産業上の利用可能性  Industrial applicability
[0065] 本発明は、パケット通信を用いる通信装置に適用可能である。  The present invention is applicable to a communication device that uses packet communication.

Claims

請求の範囲 The scope of the claims
[1] サブキャリア適応変調により通信を行う無線通信システムであって、無線伝搬路情 報に基づいてサブキャリア毎又はブロック毎に変調方式と符号化率とを決定して通信 を行う無線通信システムに用いられる送信機において、  [1] A wireless communication system that performs communication by subcarrier adaptive modulation, and performs communication by determining a modulation scheme and a coding rate for each subcarrier or block based on wireless propagation path information In the transmitter used for
前記無線伝搬路情報から決定された前記変調方式と前記符号化率とに基づいて 送信容量を算出し、算出された送信容量に基づいて送信対象として再送パケットと 新規パケットとのいずれを送信するかを判定する再送判定手段を有することを特徴と する送信機。  A transmission capacity is calculated based on the modulation scheme determined from the radio propagation path information and the coding rate, and a retransmission packet or a new packet is transmitted as a transmission target based on the calculated transmission capacity. A transmitter characterized by having retransmission determination means for determining
[2] 前記無線伝搬路情報に基づいて決定された前記変調方式と前記符号化率とから 算出した送信容量と再送パケット容量とが近似していることを、再送パケットを送るた めの条件とすることを特徴とする請求項 1に記載の送信機。  [2] The condition for sending the retransmission packet is that the transmission capacity calculated from the modulation scheme determined based on the radio propagation path information and the coding rate is approximate to the retransmission packet capacity. The transmitter according to claim 1, wherein:
[3] 前記送信容量が、前記再送パケットの送信に適している場合には、該再送パケット を優先して送信することを特徴とする請求項 1又は 2に記載の送信機。 [3] The transmitter according to claim 1 or 2, wherein, when the transmission capacity is suitable for transmission of the retransmission packet, the retransmission packet is preferentially transmitted.
[4] 前記再送判定手段は、通信品質 (Qos)に基づいて再送パケットの再送判定回数を 決定することを特徴とする請求項 1又は 2に記載の送信機。 [4] The transmitter according to claim 1 or 2, wherein the retransmission determination means determines the number of retransmission determinations of a retransmission packet based on communication quality (Qos).
[5] 前記再送判定手段は、ある再送遅延時間内に限って再送判定を行うことを特徴と する請求項 1から 4までのいずれ力 4項に記載の送信機。 5. The transmitter according to any one of claims 1 to 4, wherein the retransmission determination means performs retransmission determination only within a certain retransmission delay time.
[6] 通信品質 (Qos)に基づいて再送に関する判定間隔を変更することを特徴とする請 求項 2から 5までのいずれ力、 1項に記載の送信機。 [6] The transmitter according to item 1, wherein the determination interval for retransmission is changed based on communication quality (Qos).
[7] 前記無線伝搬路情報に基づいて決定された前記変調方式と前記符号化率とから 算出した送信容量と再送パケット容量とが近似していない場合において、再送バケツ ト容量を分割し、分割されたうちのいずれかのパケット容量と前記送信容量とが近似 していることを、再送パケットを送るための条件とすることを特徴とする請求項 4に記載 の送信機。 [7] When the transmission capacity calculated from the modulation scheme determined based on the radio channel information and the coding rate is not close to the retransmission packet capacity, the retransmission packet capacity is divided and divided. 5. The transmitter according to claim 4, wherein a condition for sending a retransmission packet is that a packet capacity of any of the received packets is approximate to the transmission capacity.
[8] 複数の再送パケット又は再送パケットと新規パケットとを合成して送信することを特 徴とする請求項 1から 7までのいずれか 1項に記載の送信機。  [8] The transmitter according to any one of [1] to [7], wherein a plurality of retransmission packets or a retransmission packet and a new packet are combined and transmitted.
[9] 送信機と受信器とを備え、サブキャリア適応変調による無線通信システムであって、 無線伝搬路情報に基づいてサブキャリア毎又はブロック毎に変調方式と符号化率と を決定して通信を行う N—チャネルストップ ·アンド'ウェイト方式無線通信システムに 用いられる送信機において、 [9] A radio communication system that includes a transmitter and a receiver and uses subcarrier adaptive modulation, and includes a modulation scheme and a coding rate for each subcarrier or each block based on radio propagation path information. In a transmitter used in an N-channel stop-and-wait wireless communication system
前記無線伝搬路情報から決定された前記変調方式と前記符号化率とに基づいて 送信容量を算出し、算出された送信容量に基づいて送信対象として再送パケットと 新規パケットとのいずれにするかを判定する再送判定手段を有することを特徴とする 送信機。  A transmission capacity is calculated based on the modulation scheme determined from the radio propagation path information and the coding rate, and a retransmission packet or a new packet is selected as a transmission target based on the calculated transmission capacity. Transmitter characterized by having retransmission determination means for determining.
[10] 算出された送信容量に基づいて、再送信パケットの送信チャネルを入れ替える制 御を行うことを特徴とする請求項 9に記載の送信機。  10. The transmitter according to claim 9, wherein control is performed to switch the transmission channel of retransmission packets based on the calculated transmission capacity.
[11] 前記パケットを複数合成して送信する制御を行うことを特徴とする請求項 1から 10ま でのレ、ずれか 1項に記載の送信機。 [11] The transmitter according to any one of [1] to [10], wherein control is performed to combine and transmit a plurality of the packets.
[12] 再送パケットの変調方式'符号ィ匕率を決定する場合に、新規パケットの変調方式- 符号化率を決定する閾値より低い閾値に設定して再送パケットの変調方式'符号化 率を決定することを特徴とする請求項 1から 11までのいずれ力 1項に記載の送信機。 [12] When determining the retransmission packet modulation method 'code rate', set the threshold lower than the threshold for determining the new packet modulation method-coding rate, and determine the retransmission packet modulation method 'coding rate. The transmitter according to any one of claims 1 to 11, characterized by:
[13] 前記無線通信システムが Nチャネルストップ 'アンド 'ウェイト方式である場合におい て、 [13] When the wireless communication system is an N-channel stop 'and' wait method,
前記再送判定手段が前記再送パケットを送信する場合に、チャネルを入れ替える 制御を行うことを特徴とする請求項 1に記載の無線通信システム。  2. The radio communication system according to claim 1, wherein when the retransmission determination unit transmits the retransmission packet, control is performed to switch channels.
[14] 請求項 1から 12までのいずれか 1項に記載の送信機と、該送信機と通信を行う受信 機と、を有する無線通信システム。 [14] A wireless communication system comprising the transmitter according to any one of claims 1 to 12 and a receiver that communicates with the transmitter.
[15] 基地局と移動局とを含み、サブキャリア適応変調により通信を行う無線通信システ ムにおける基地局であって、 [15] A base station in a radio communication system that includes a base station and a mobile station and performs communication by subcarrier adaptive modulation,
送信データ容量を算出する送信データ容量算出部と、  A transmission data capacity calculator for calculating the transmission data capacity;
以前送信したパケットの Ack/Nack情報を送る制御情報処理部と、  A control information processor that sends Ack / Nack information of previously transmitted packets;
新規送信データが入力される送信データ制御部であって、前記 Ack/Nack情報 と、算出された前記送信データ容量と、に基づいて、新規パケットと再送パケットとの いずれを送信するかを判定する送信データ制御部と、  A transmission data control unit to which new transmission data is input, and determines whether to transmit a new packet or a retransmission packet based on the Ack / Nack information and the calculated transmission data capacity A transmission data control unit;
送信する方のパケットを受けて伝搬路情報に基づく変調方式'符号ィヒ率でデータ の変調'符号化を行うデータ処理部と、 該データ処理部からのデータを受けてデータ変調された信号を移動局に送信する 無線送信部と A data processing unit that receives a packet to be transmitted and performs encoding based on propagation path information 'modulation of data with a code ratio'encoding; A radio transmission unit that receives data from the data processing unit and transmits a data-modulated signal to the mobile station;
を有することを特徴とする基地局。  A base station characterized by comprising:
[16] 前記データ処理部が前記無線送信部にデータを渡す際に、移動局が無線区間の 伝搬路推定を行う為のパイロットデータとデータに対する変調方式 ·符号ィ匕率とに関 する情報をデータに付加することを特徴とする請求項 15に記載の基地局。  [16] When the data processing unit passes the data to the wireless transmission unit, the mobile station uses the pilot data for performing propagation path estimation in the wireless section and information on the modulation scheme and code rate for the data. 16. The base station according to claim 15, which is added to data.
[17] 前記無線送信部は、データ変調された信号を無線周波数帯にアップコンバートし、 各サブキャリアの送信電力を一定にして移動局に送信することを特徴とする請求項 1 5又は 16に記載の基地局。  17. The radio transmission unit according to claim 15, wherein the radio transmission unit upconverts the data-modulated signal to a radio frequency band, and transmits the signal to a mobile station with a constant transmission power of each subcarrier. The listed base station.
[18] 前記送信データ制御部は、新規パケットを送信する場合に新規送信データをパケ ット化し、前記データ処理部に送るとともに、再送パケットを、再送処理の為にバッフ ァに送り、  [18] When the transmission data control unit transmits a new packet, the transmission data control unit packetizes the new transmission data and sends the packet to the data processing unit, and also sends the retransmission packet to the buffer for retransmission processing.
該バッファにおいて前記再送パケットを一時的に保存し、前記再送パケットを送信 する場合には、前記送信データ制御部が前記バッファに保存されている再送データ を抽出して前記データ処理部に送ることを特徴とする請求項 15から 17までのいずれ 力 1項に記載の基地局。  When the retransmission packet is temporarily stored in the buffer and the retransmission packet is transmitted, the transmission data control unit extracts the retransmission data stored in the buffer and sends it to the data processing unit. The base station as set forth in any one of claims 15 to 17,
[19] さらに、前記制御情報処理部からの Ack/Nack情報に基づいて、送信に成功した 再送パケットを前記バッファから消去することを特徴とする請求項 18に記載の基地局 [19] The base station according to claim 18, further comprising: deleting a retransmission packet that has been successfully transmitted from the buffer based on Ack / Nack information from the control information processing unit.
[20] 基地局と移動局とを含み、サブキャリア適応変調により通信を行う無線通信システ ムにおける移動局であって、 [20] A mobile station in a radio communication system that includes a base station and a mobile station and performs communication by subcarrier adaptive modulation,
基地局からのパケットデータに関する判定を行うパケット判定部であって、受信した パケットが正しいか否力、を判定し、受信パケットが正しくない場合は、パケットを破棄 するか又は再送パケットとの合成を行うためにバッファに一時保存しておくことを特徴 とする移動局。  A packet decision unit that makes a decision on packet data from the base station, and determines whether or not the received packet is correct. If the received packet is incorrect, the packet is discarded or combined with a retransmitted packet. A mobile station characterized by being temporarily stored in a buffer for execution.
[21] サブキャリア適応変調により通信を行う無線通信方法であって、  [21] A wireless communication method for performing communication by subcarrier adaptive modulation,
移動局からの通知された AckZNack情報から、再送するパケットがあるか否かを 確認するステップと、 再送するパケットがある場合に、移動局から通知される伝搬路情報に基づいてサブ キャリア毎又はブロック毎の変調方式 ·符号化率を算出するステップと、 A step of checking whether there is a packet to be retransmitted from the AckZNack information notified from the mobile station; A step of calculating a modulation scheme and a coding rate for each subcarrier or each block based on propagation path information notified from the mobile station when there is a packet to be retransmitted;
算出されたサブキャリア毎の変調方式'符号化率から送信パケットの送信ビット容量 を算出するステップと、  Calculating the transmission bit capacity of the transmission packet from the calculated modulation scheme for each subcarrier 'coding rate;
算出された送信ビット容量と再送パケット容量とを比較し、再送パケットを送信に適 していると判断された場合に再送パケットを送信し、適していないと判断された場合 に新規パケットを送信するステップと  The calculated transmission bit capacity is compared with the retransmission packet capacity, and when it is determined that the retransmission packet is suitable for transmission, the retransmission packet is transmitted, and when it is determined that it is not suitable, a new packet is transmitted. Step and
を有することを特徴とする無線通信方法。  A wireless communication method comprising:
[22] サブキャリア適応変調により通信を行う無線通信方法であって、 [22] A wireless communication method for performing communication by subcarrier adaptive modulation,
移動局からの通知された AckZNack情報から、再送するパケットがあるか否かを 確認するステップと、  A step of checking whether there is a packet to be retransmitted from the AckZNack information notified from the mobile station;
再送するパケットがある場合に、移動局から通知される伝搬路情報に基づいてサブ キャリア毎又はブロック毎の変調方式 ·符号化率を算出するステップと、  A step of calculating a modulation scheme and a coding rate for each subcarrier or each block based on propagation path information notified from the mobile station when there is a packet to be retransmitted;
算出されたサブキャリア毎の変調方式'符号化率から送信パケットの送信ビット容量 を算出するステップと、  Calculating the transmission bit capacity of the transmission packet from the calculated modulation scheme for each subcarrier 'coding rate;
算出された送信ビット容量と再送パケット容量とを比較し、再送パケットを送信に適 していると判断された場合に再送パケットを送信し、適していないと判断された場合 に算出された送信ビット容量と再送パケット群の容量とを比較し、再送パケット群の送 信に適していると判断された場合に再送パケット群を送信し、再送パケット群の送信 に適していないと判断された場合に新規パケットを送信するステップと  The calculated transmission bit capacity is compared with the retransmission packet capacity, and when it is determined that the retransmission packet is suitable for transmission, the retransmission packet is transmitted, and when it is determined that the retransmission packet is not suitable, the transmission bit calculated When the capacity is compared with the capacity of the retransmission packet group, the retransmission packet group is transmitted when it is determined to be suitable for transmission of the retransmission packet group, and when it is determined not suitable for transmission of the retransmission packet group. Sending a new packet and
を有することを特徴とする無線通信方法。  A wireless communication method comprising:
[23] サブキャリア適応変調により通信を行う無線通信方法であって、 [23] A wireless communication method for performing communication by subcarrier adaptive modulation,
移動局からの通知された AckZNack情報から再送するパケットがあるか否かを確 認するステップと、  Checking whether there is a packet to be retransmitted from the AckZNack information notified from the mobile station;
再送するパケットがある場合は判定回数 N= lとし、移動局から通知される伝搬路 情報からサブキャリア毎の変調方式 ·符号ィヒ率を算出するステップと、  When there is a packet to be retransmitted, the number of determinations is set to N = l, and a modulation scheme for each subcarrier is calculated from propagation path information notified from the mobile station.
算出されたサブキャリア毎の変調方式 ·符号化率から送信パケットの送信ビット容量 を算出するステップと、 再送パケットの判定回数 Nが繰り返し回数 X以上の場合に、パケット識別フラグに 1 をセットして再送パケットを送信するステップと A step of calculating a transmission bit capacity of a transmission packet from the calculated modulation scheme for each subcarrier A step of transmitting a retransmission packet with the packet identification flag set to 1 when the number of retransmission packet determination N is equal to or greater than the number of repetitions X;
を有することを特徴とする無線通信方法。  A wireless communication method comprising:
[24] 1回で送信できなレ、場合は、パケットを分割して送るステップを含むことを特徴とす る請求項 23に記載の無線通信方法。 24. The wireless communication method according to claim 23, further comprising a step of dividing and transmitting the packet that cannot be transmitted at one time.
[25] 1回で送信できない場合は、初回の変調方式'符号化率で送信するなどの 1回で送 信するステップを含むことを特徴とする請求項 23に記載の無線通信方法。 [25] The wireless communication method according to claim 23, further comprising a step of transmitting in one time, such as transmitting in the first modulation scheme “coding rate” when transmission is not possible in one time.
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