Base station, terminal and communication method

Abstract

A base station includes: a control circuit that determines to activate or deactivate a frequency diversity transmission scheme configured to transmit information at different frequencies based on whether an operation of retransmission control is ON or OFF; and a communication circuit that performs communication with a terminal with the frequency diversity transmission scheme in a case where the frequency diversity transmission scheme is determined to be activated, and performs communication with the terminal without the frequency diversity transmission scheme in a case where the frequency diversity transmission scheme is determined to be deactivated.

Description

[0001] This application is a divisional application of the invention patent application with application number 202080027330.3 and invention name “Base Station, Terminal and Communication Method” filed on January 22, 2020. Technical Field

[0002] The present disclosure relates to a base station, a terminal and a communication method. Background Art

[0003] As a successor standard to the IEEE 802.11ax standard of the Institute of Electrical and Electronics Engineers (IEEE) 802.11, research is underway on the IEEE 802.11be standard for the next generation wireless local area network (LAN). IEEE 802.11be is also known as "Extreme High Throughput (EHT)", for example.

[0004] In IEEE 802.11be, introduction of retransmission control (for example, Hybrid Automatic Repeat Request (HARQ)) is discussed (for example, see Non-Patent Document 1).

[0005] Prior art literature

[0006] Non-patent literature

[0007] Non-patent document 1: IEEE 802.11-18 / 2029r1, HARQ in EHT

[0008] Non-patent document 2: IEEE P802.11ax TM / D4.0 Summary of the invention

[0009] However, a method for retransmission control based on the communication quality in wireless communications such as wireless LANs has not yet been fully studied.

[0010] The non-limiting embodiments of the present disclosure contribute to providing a base station, a terminal, and a communication method capable of improving the efficiency of retransmission control according to communication quality.

[0011] A base station according to an embodiment of the present disclosure comprises: a control circuit that determines one of a retransmission control action and a communication parameter set according to communication quality; and a communication circuit that communicates with a terminal based on the determined communication parameter or the retransmission control action.

[0012] It should be noted that these general or specific aspects may be implemented by a system, an apparatus, a method, an integrated circuit, a computer program or a recording medium, or may be implemented by any combination of systems, apparatuses, methods, integrated circuits, computer programs and recording media.

[0013] According to one embodiment of the present disclosure, it is possible to improve the efficiency of retransmission control according to communication quality.

[0014] More advantages and effects of an embodiment of the present disclosure will be explained through the description and drawings. These advantages and / or effects are provided by several embodiments, and the features described in the description and drawings, but not necessarily all of them need to be provided in order to obtain one or more of the same features. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a diagram showing a structural example of a physical layer protocol data unit (PHY Protocol Data Unit: PPDU).

[0016] Figure 2 This is a diagram showing an example of the structure of a preamble during an extended range operation.

[0017] Figure 3 This is a diagram showing an example of a constellation diagram of HE-SIG-A symbols.

[0018] Figure 4 This is a diagram showing an operation example of dual carrier modulation (Dual Carrier Modulation: DCM).

[0019] Figure 5 : is a diagram showing an example of the relationship between the extended range, DCM, and the communication area.

[0020] Figure 6 This is a block diagram showing a partial configuration example of an access point (also referred to as "access point (AP)" or "base station") according to the first embodiment.

[0021] Figure 7 This is a block diagram showing a partial configuration example of a terminal (or also referred to as a "station (STA)") according to the first embodiment.

[0022] Figure 8 This is a block diagram showing a structural example of an AP according to the first embodiment.

[0023] Fig. 9 This is a block diagram showing a structural example of STA according to implementation mode 1.

[0024] Fig.10 This is a diagram showing an example of the relationship between the communication mode and the HARQ operation according to the first embodiment.

[0025] Fig.11 This is a diagram showing an example of the relationship between the communication mode and the HARQ operation according to the first embodiment.

[0026] Fig.12 This is a diagram showing an example of the relationship between the communication mode and the HARQ operation according to the first embodiment.

[0027] Fig.13 This is a diagram showing an example of the relationship between MCS and HARQ operation in the first embodiment.

[0028] Fig.14 This is a diagram showing an example of the relationship between the number of space-time streams and the HARQ operation according to the first embodiment.

[0029] Fig.15 This is a diagram showing an example of the relationship between the bandwidth and the HARQ operation in the first embodiment.

[0030] Fig.16 This is a diagram showing an example of the relationship between resource unit (RU) allocation and HARQ operation according to the first embodiment.

[0031] Fig.17 This is a sequence diagram showing an operation example of the wireless communication system according to the first embodiment.

[0032] Fig.18 This is a diagram showing a configuration example of SIG-A according to the first embodiment.

[0033] Fig.19 This is a sequence diagram showing an operation example of the wireless communication system according to the first embodiment.

[0034] Fig. 20 This is a diagram showing a configuration example of SIG-A according to the first embodiment.

[0035] Fig.21 This is a diagram showing a configuration example of SIG-A according to the first embodiment.

[0036] Fig. 22 This is a diagram showing a setting example of the SIG-A constellation diagram according to the first embodiment.

[0037] Fig.23 This is a block diagram showing a structural example of an AP according to the second embodiment.

[0038] Fig.24 This is a block diagram showing a structural example of STA according to implementation mode 2.

[0039] Fig.25 This is a diagram showing an example of the relationship between the HARQ action and the communication mode in the second embodiment.

[0040] Fig.26 This is a diagram showing an example of the relationship between the HARQ action and the communication mode in the second embodiment.

[0041] Fig. 27 This is a diagram showing an example of the relationship between the HARQ action and the communication mode in the second embodiment.

[0042] Fig.28 This is a sequence diagram showing an example of the operation of the wireless communication system according to the second embodiment.

[0043] Fig.29 This is a diagram showing an example of setting communication parameters according to the second embodiment.

[0044] Fig.30 This is a diagram showing an example of setting communication parameters according to the second embodiment.

[0045] Fig.31 This is a sequence diagram showing an example of the operation of the wireless communication system according to the third embodiment. DETAILED DESCRIPTION

[0046] Hereinafter, each embodiment of the present disclosure will be described in detail with reference to the drawings.

[0047] [HARQ control]

[0048] HARQ is retransmission control in the physical (PHY) layer, which is different from retransmission control in the medium access control (MAC) layer. In HARQ, for example, a terminal (or also called a "station (STA)") holds the physical layer packet data with errors in the packet data sent from an access point (also called an "access point (AP)" or a "base station") and requests retransmission. For example, the STA combines the physical layer packet data retransmitted from the AP with the held packet data. HARQ can improve the reception performance in the STA and improve the throughput.

[0049] The retransmission method in HARQ (or also called "HARQ type") includes two methods, such as chase combining (CC) and incremental redundancy (IR). CC is a method of retransmitting the same packet as the new transmission (or "initial transmission"). In addition, IR is a method of adding new parity bits during retransmission to increase the coding gain.

[0050] For example, in IEEE 802.11be, whether to adopt one or both of the above HARQ types, or how to incorporate the HARQ mechanism into the wireless LAN system, etc. are being studied.

[0051] In addition, in IEEE 802.11be, there is room for research on the signaling notification method related to HARQ control. Figure 1 As shown, when a field for allocating signaling related to HARQ control (for example, represented as "HARQ-SIG") is added to SIG-A or other areas, overhead increases and throughput decreases.

[0052] Therefore, in one embodiment of the present disclosure, a method for improving HARQ control efficiency according to communication quality is described.

[0053] [Range extension and DCM]

[0054] In IEEE 802.11ax, communication modes such as extended range (ER) and dual carrier modulation (DCM) are introduced (for example, see non-patent document 2). Extended range can extend the communication distance, for example. In addition, DCM can improve robustness, for example.

[0055] The extended range can be achieved by extending the communication distance, for example, through the following method (1) and method (2).

[0056] Method (1): In the extended range, for example, in the PPDU format, at least one of the legacy short training field (Legacy-Short Training Field: L-STF) and the legacy long training field (Legacy-Long Training Field: L-LTF) is power-boosted (for example, by 3 dB power boost) (for example, see Figure 2 Alternatively, in the extended range, for example, in the PPDU format, at least one of the legacy signaling (Legacy-SIGNAL: L-SIG) and the high efficiency signaling-A (High Efficiency-SIGNAL-A: HE-SIG-A) is repeatedly transmitted (in other words, repetition) (for example, see Figure 2 ). By power boosting and repeated transmission, it is possible to improve (in other words, alleviate) the reception quality of the preamble code on the receiving side (for example, also referred to as "preamble code performance").

[0057] Method (2): During the range-extending action, a portion of the parameters that can be used for communication is set. In other words, during the range-extending action, the parameters that can be set are limited to a portion. For example, during the range-extending action, the channel used is set to the main 20 MHz channel, the modulation and coding scheme (MCS) is set to one of MCS0, MCS1, and MCS2, the number of space time streams (STS) is set to 1 STS, and the resource unit (RU) size is set to 242tone or 106tone. This can improve the reliability of communication.

[0058] In addition, IEEE 802.11ax also specifies the format of the PPDU dedicated to the extended range (for example, "HE ER SUPPDU").

[0059] In HEER SU PPDU, for example Figure 2 As shown, the HE-SIG-A field is composed of four fields: HE-SIG-A1, HE-SIG-A2, HE-SIG-A3, and HE-SIG-A4. Figure 2 In the present disclosure, the same data is contained in HE-SIG-A1 and HE-SIG-A2 (in other words, repeated transmission is applied), and the same data is contained in HE-SIG-A3 and HE-SIG-A4 (in other words, repeated transmission is applied).

[0060] In addition, for example Figure 3 As shown, in the HE ER SU PPDU format, the constellation diagram of HE-SIG-A2 is a constellation diagram of other HE-SIG-A (e.g., HE-SIG-A1, HE-SIG-A3 and HE-SIG-A4) (e.g., quadrature binary phase shift keying (Binary Phase Shift Keying: BPSK) with the phase rotated 90 degrees). As a result, the STA can distinguish the HE ER SU PPDU format from other formats based on the constellation diagram of HE-SIG-A2. Therefore, for example, the STA can identify the HE ER-SU PPDU and other formats before decoding the HE-SIG-A.

[0061] For example Figure 4 As shown, DCM is a transmission side through different mapping ( Figure 4 Mapping 1 and Mapping 2 in different subcarriers ( Figure 4The same information bits are sent on subcarrier n and carrier m in the DCM. Through DCM, the communication quality can be improved through the diversity effect of synthesis and decoding at the receiving side.

[0062] When DCM is in operation, some parameters that can be used for communication are set. In other words, when DCM is in operation, the parameters that can be set are limited to some. For example, when DCM is in operation, MCS is set to one of MCS0, MCS1, MCS3, and MCS4, the number of STS is set to one of 1STS to 2STS, and the operation combining DCM and space-time block coding (STBC) is not set (in other words, it is set to an operation without STBC).

[0063] In IEEE 802.11be, the introduction of extended range and DCM is also being studied.

[0064] Here, if Figure 5 As shown, the communication quality of the STA is determined, for example, by the distance from the AP. In addition, for example, the setting of the extended range and DCM for the STA (for example, one of ON and OFF) can be controlled based on the communication quality of the STA. For example, since the STA closer to the AP ( Figure 5 The better the communication quality, the easier it is to set the extended range and DCM. Figure 5 The worse the communication quality is, the easier it is to set the extended range and DCM.

[0065] In addition, the worse the communication quality of the STA, the greater the effect of HARQ on improving the throughput. In other words, the HARQ action can be controlled (for example, to either ON or OFF) based on the communication quality of the STA.

[0066] In this way, both the setting of the communication mode such as extended range and DCM and the operation of HARQ control can be controlled according to the communication quality of the STA.

[0067] Therefore, in one embodiment of the present disclosure, a method of associating an action of HARQ control with a parameter (eg, communication mode) set according to communication quality is described.

[0068] In addition, the communication mode is not limited to extended range and DCM, and may be other parameters set according to the communication quality, such as MCS, signal-to-noise ratio (SNR), number of STSs, bandwidth, or RU allocation.

[0069] In addition, communication quality is not limited to Figure 5The distance between the AP and the STA shown (in other words, the communication distance) can also be represented by other parameters. For example, the communication quality can be represented by at least one of parameters such as the communication distance, the amount of interference, the SNR, and the error rate.

[0070] (Embodiment 1)

[0071] [Structure of Wireless Communication System]

[0072] The wireless communication system of this embodiment includes at least one AP100 and at least one STA200.

[0073] Figure 6 is a block diagram showing a partial structure example of the AP100 according to an embodiment of the present disclosure. In Figure 6 the shown AP100, the HARQ control unit 108 (for example, equivalent to a control circuit) determines one based on either the retransmission control operation (for example, HARQ operation) and the communication parameters (for example, communication mode) set according to the communication quality. The wireless transceiver unit 103 (for example, equivalent to a communication circuit) communicates with the STA200 (for example, a terminal) based on the determined communication parameters or the retransmission control operation.

[0074] Figure 7 is a block diagram showing a partial structure example of the STA200 according to an embodiment of the present disclosure. In Figure 7 the shown STA200, the received packet decoding unit 206 (for example, equivalent to a control circuit) determines one based on either the retransmission control operation and the communication parameters set according to the communication quality. The wireless transceiver unit 203 (equivalent to a communication circuit) communicates with the AP100 (for example, a base station) based on the determined communication parameters or the retransmission control operation.

[0075] [Structural Example of AP100]

[0076] Figure 8 is a block diagram showing a structural example of the AP100. Figure 8 The shown AP100 includes, for example, a transmission packet generation unit 101, a modulation unit 102, a wireless transceiver unit 103, an antenna 104, a demodulation unit 105, a received packet decoding unit 106, a communication mode determination unit 107, and a HARQ control unit 108.

[0077] The transmission packet generation unit 101 generates a transmission packet including a preamble and data based on the input transmission data. For example, the transmission packet may include communication mode information related to the communication mode (e.g., extended range and DCM, etc.) input from the communication mode determination unit 107 and HARQ control information related to HARQ control input from the HARQ control unit 108. The transmission packet generation unit 101 outputs the generated transmission packet to the modulation unit 102.

[0078] The modulation unit 102 performs modulation processing on the transmission packet input from the transmission packet generation unit 101. When the information input from the communication mode determination unit 107 indicates an extended range operation, the modulation unit 102 performs modulation processing on the transmission packet input from the transmission packet generation unit 101. Figure 3 As shown, the constellation diagram of SIG-A2 can be set to QBPSK. In addition, for example, when the HARQ control information is defined in association with at least one of the constellations of SIG-A2 to SIG-A4, the modulation unit 102 can also set the constellations of SIG-A2 to SIG-A4 in association with the HARQ control information. The modulation unit 102 outputs the modulated signal to the wireless transceiver unit 103.

[0079] The wireless transceiver 103 communicates with, for example, the STA 200. For example, the wireless transceiver 103 performs wireless transmission processing on the signal input from the modulation unit 102, and transmits the wireless signal from the antenna 104. In addition, the wireless transceiver 103 performs wireless reception processing on the wireless signal received by the antenna 104, and outputs the received signal after the wireless reception processing to the demodulation unit 105.

[0080] The demodulation unit 105 performs demodulation processing on the reception signal input from the wireless transmission and reception unit 103 , and outputs the demodulated signal to the reception packet decoding unit 106 .

[0081] The reception packet decoding unit 106 performs a decoding process on the signal (for example, including the preamble and data transmitted from the STA 200) input from the demodulation unit 105. The reception packet decoding unit 106 outputs information indicating the communication quality of the STA 200, which is included in the decoded signal, to the communication mode determination unit 107, for example. In addition, the reception packet decoding unit 106 outputs a signal indicating a response to the transmission packet transmitted from the STA 200 (for example, also referred to as "HARQ response", "HARQ-ACK" or "ACK / NACK") to the HARQ control unit 108. In addition, the reception packet decoding unit 106 outputs the data (in other words, the reception data) included in the decoded signal.

[0082] The communication mode determination unit 107 determines the communication mode based on the communication quality of the STA 200 indicated by the information input from the received packet decoding unit 106. The communication mode can be, for example, at least one of range extension and DCM, or can be at least one of parameters determined by communication quality such as range extension, DCM, MCS, number of STSs, bandwidth, and RU allocation information. The communication mode determination unit 107 outputs communication mode information indicating the determined communication mode to the transmission packet generation unit 101, the modulation unit 102, and the HARQ control unit 108.

[0083] Based on the information input from the received packet decoding unit 106 (e.g., HARQ response), the HARQ control unit 108 controls the transmission process of the transmission packet (e.g., initial transmission or retransmission). For example, the HARQ control unit 108 performs initial transmission control of the transmission packet when the HARQ response indicates acknowledgement (ACK), and performs retransmission control of the transmission packet when the HARQ response indicates non-acknowledgement (NACK). For example, in the retransmission of the transmission packet, the HARQ control unit 108 sets a value indicating retransmission instruction or retransmission as the new data indicator (NDI). In addition, when the HARQ response is ACK, or when the AP 100 has not received ACK nor NACK, the HARQ control unit 108 sets a toggled NDI value indicating initial transmission instruction or initial transmission.

[0084] In addition, the HARQ control unit 108 determines the HARQ operation based on the communication mode information input from the communication mode determination unit 107. In addition, an example of the method for determining the HARQ operation based on the communication mode in the HARQ control unit 108 will be described later.

[0085] The HARQ control unit 108 outputs HARQ control information indicating the content of HARQ control to the transmission packet generation unit 101 and the modulation unit 102, for example.

[0086] <Structural example of STA 200>

[0087] Fig. 9 It is a block diagram showing a structural example of the STA 200. Fig. 9 The STA 200 shown, for example, includes a transmission packet generation unit 201, a modulation unit 202, a wireless transceiver unit 203, an antenna 204, a demodulation unit 205, a received packet decoding unit 206, and a communication quality measurement unit 207.

[0088] The transmission packet generation unit 201 generates a transmission packet including a preamble and data based on the input transmission data. For example, the transmission packet may include communication quality information related to the communication quality input from the communication quality measurement unit 207 and ACK / NACK information input from the reception packet decoding unit 206. The transmission packet generation unit 201 outputs the generated transmission packet to the modulation unit 202.

[0089] The modulation unit 202 performs modulation processing on the transmission packet input from the transmission packet generation unit 201. The modulation unit 202 outputs the modulated signal to the wireless transmission / reception unit 203.

[0090] The wireless transceiver 203 communicates with, for example, the AP 100. For example, the wireless transceiver 203 performs wireless transmission processing on the signal input from the modulation unit 202, and transmits the wireless signal from the antenna 204. In addition, the wireless transceiver 203 performs wireless reception processing on the wireless signal received by the antenna 204, and outputs the received signal after the wireless reception processing to the demodulation unit 205.

[0091] The demodulation unit 205 performs demodulation processing on the reception signal input from the wireless transmission / reception unit 203 , and outputs the demodulated signal to the reception packet decoding unit 206 and the communication quality measurement unit 207 .

[0092] The reception packet decoding unit 206 performs decoding processing on the signal (including, for example, the preamble and data transmitted from the AP 100) input from the demodulation unit 205. The reception packet decoding unit 206 outputs, for example, reception data (in other words, reception packet data) included in the decoded signal.

[0093] The received packet decoder 206 determines the HARQ action based on the communication mode set by the control signal included in the received packet, for example, similarly to the HARQ control unit 108 of the AP 100. An example of a method for determining the HARQ action based on the communication mode in the received packet decoder 206 will be described later.

[0094] For example, when performing HARQ operation, the reception packet decoding unit 206 performs error detection on the reception data, and outputs ACK / NACK information (ACK or NACK) based on the error detection result to the transmission packet generation unit 201. For example, when the reception data has an error, the reception packet decoding unit 206 holds the reception data, generates ACK / NACK information requesting retransmission (NACK), and synthesizes the retransmitted packet data with the held reception data. Thus, the reception performance can be improved. In addition, when the reception data has no error, the reception packet decoding unit 206 generates ACK / NACK information indicating ACK.

[0095] The communication quality measuring unit 207 measures the communication quality between the AP 100 and the STA 200, for example, based on the demodulated signal input from the demodulation unit 205. The communication quality may be, for example, SNR, or information indicating the quality of the communication distance, propagation loss, interference amount, error rate, or channel quality information (CQI). The communication quality measuring unit 207 outputs the communication quality information indicating the measured communication quality to the transmission packet generating unit 201.

[0096] In addition, in one embodiment of the present disclosure, either the MAC layer or the physical layer may be used in the feedback of the ACK / NACK information. For example, in the format of the ACK / NACK information, it may also be possible to define an "ACK / NACK frame format" similar to the "ACK frame format" defined as one of the MAC frame formats of IEEE 802.11ax, and the "ACK / NACK frame format" is used to explicitly notify ACK / NACK as one of the MAC frame formats. Alternatively, it may also be defined by including the format of the ACK / NACK information in the signaling of the physical layer. In addition, in one embodiment of the present disclosure, the retransmission control at the MAC layer level and the HARQ retransmission control at the physical layer level in IEEE 802.11ax may also be switched.

[0097] In addition, as one of the formats of confirmation responses to multiple MAC Protocol Data Units (MAC Protocol Data Unit: MPDU), there is a "block ACK frame format". In one embodiment of the present disclosure, in the case of HARQ retransmission, a "block ACK / NACK frame format" that includes NACK information in addition to ACK information may also be defined. The object of block ACK / NACK may be ACK / NACK corresponding to the MPDU, or ACK / NACK corresponding to each of the multiple PPDUs divided into. In addition, in one embodiment of the present disclosure, the block ACK frame format and the block ACK / NACK frame format for HARQ may also be switched.

[0098] [Relationship between communication mode and HARQ operation]

[0099] Next, the relationship between the communication mode and the HARQ operation according to the present embodiment will be described.

[0100] Here, as an example, the association between the communication mode in which at least one of the extended range and the DCM is set and the HARQ operation will be described.

[0101] Next, setting examples 1 to 3 of the association between the communication mode and the HARQ operation will be described respectively.

[0102] <Setting Example 1>

[0103] In setting example 1, the HARQ action or HARQ type is switched based on the extended range setting.

[0104] Fig.10 An example of the association between the extended range setting and the HARQ operation is shown.

[0105] In an extended-range action environment (for example, indicated as "extended-range action: ON"), for example, there is a high possibility that the communication quality of STA200 is low quality (for example, the communication quality is less than a threshold), and the HARQ action has a great effect on improving the communication quality, and the throughput can be easily improved through the HARQ action.

[0106] On the other hand, in an environment where the extended range is not in operation (for example, indicated as "extended range operation: OFF"), for example, the communication quality of STA200 is likely to be high (for example, the communication quality is above the threshold), and the HARQ operation has little effect on improving the communication quality. Therefore, when the extended range is not in operation, it is difficult to improve the throughput by the HARQ operation.

[0107] So, for example, in Fig.10 In the HARQ action regulation example 1 shown, when the extended range is set, the HARQ action is set, and when the extended range is not set, the HARQ action is not set. In addition, the presence or absence of the setting of the HARQ action or communication mode (for example, extended range and DCM) can be expressed as "action / non-action", "ON / OFF", "valid / invalid", "apply / non-apply", "activate / deactivate" or "enable / disable", etc.

[0108] In addition, in a low-quality environment of extended-range operation, the coding gain through IR and the maximum ratio synthesis gain through CC will be equal. In addition, among HARQ types, the amount of control information of CC is less than that of IR. Therefore, Fig.10 As shown in the HARQ operation definition example 2, when the extended range is set (ON), by setting the HARQ type to CC, it is possible to reduce overhead and improve throughput.

[0109] On the other hand, in a high-quality environment without extended range, the coding gain ratio through IR is greater than the maximum ratio synthesis gain through CC. Fig.10 As shown in the HARQ operation definition example 2, when the extended range is not set (OFF), the HARQ type is set to IR.

[0110] <Setting Example 2>

[0111] In setting example 2, the HARQ action or HARQ type is switched based on the DCM setting.

[0112] Fig.11 This is an example of the association between the DCM setting and the HARQ action.

[0113] In an environment of DCM action (for example, represented as "DCM action: ON"), for example, there is a high possibility that the communication quality of STA200 is low (for example, the communication quality is less than a threshold), and the HARQ action has a great effect on improving the communication quality, and the throughput can be easily improved through the HARQ action.

[0114] On the other hand, in an environment where DCM is not in operation (e.g., indicated as "DCM operation: OFF"), for example, the communication quality of STA200 is likely to be high (e.g., the communication quality is above the threshold), and the HARQ operation has little effect on improving the communication quality. Therefore, when DCM is not in operation, it is difficult to improve the throughput by the HARQ operation.

[0115] So, for example, in Fig.11 In the HARQ operation definition example 1 shown, when DCM is set (ON), the HARQ operation is set, and when DCM is not set (OFF), the HARQ operation is not set (non-operation).

[0116] In addition, in a low-quality environment where DCM operates, the coding gain through IR is equal to the maximum ratio synthesis gain through CC. In addition, among HARQ types, the amount of control information in CC is less than that in IR. Therefore, Fig.11 As in the HARQ operation definition example 2 shown in the figure, when DCM is set (ON), by setting the HARQ type to CC, it is possible to reduce overhead and improve throughput.

[0117] On the other hand, in a high-quality environment where DCM is not set, the coding gain through IR is greater than the maximum ratio synthesis gain through CC. Fig.11 As shown in the HARQ action definition example 2, when DCM is not set (OFF), the HARQ type is set to IR.

[0118] <Setting Example 3>

[0119] In setting example 3, the HARQ action or the HARQ type is switched based on a combination of the extended range setting and the DCM setting.

[0120] Fig.12 An example of the association between the combination of the extended range setting and the DCM setting and the HARQ operation is shown.

[0121] For example, in an environment where both the extended range and DCM are in operation, the communication quality of the STA 200 is likely to be low (for example, a state where the communication quality is less than a threshold) compared to an environment where either the extended range or DCM is in operation or an environment where neither of the extended range and DCM is in operation. Therefore, in a case where both the extended range and DCM are in operation, the effect of improving the communication quality by the HARQ operation is greater than in an environment where either the extended range or DCM is in operation or an environment where neither of the extended range and DCM is in operation, and the throughput can be easily improved by the HARQ operation.

[0122] So, for example, in Fig.12 In the HARQ operation regulation example 1 shown in FIG. 1 , when both the extended range and the DCM are set (when the extended range operation: ON and the DCM operation: ON), the HARQ operation is set. Fig.12 In the HARQ operation definition example 1 shown, when either the extended range or the DCM is set, or when neither the extended range nor the DCM is set, the HARQ operation is not set (not in operation).

[0123] In addition, in a low-quality environment where both the extended range and DCM are in operation, the coding gain through the IR is equivalent to the maximum ratio synthesis gain through the CC. In addition, among the HARQ types, the amount of control information in the CC is less than that in the IR. Therefore, Fig.12 As in the HARQ operation definition example 2 shown in FIG. 1 , when both the extended range and the DCM are set, by setting the HARQ type to CC, it is possible to reduce overhead and improve throughput.

[0124] On the other hand, in an environment where at least one of the extended range and DCM is not in operation, the coding gain through IR is greater than the maximum ratio synthesis gain through CC compared to an environment where both the extended range and DCM are in operation. Fig.12 As in the HARQ operation definition example 2 shown in FIG. 1 , when either the extended range or the DCM is set, or when neither the extended range nor the DCM is set, the HARQ type is set to IR.

[0125] In the above, setting examples 1 to 3 have been described.

[0126] In addition, the setting of the communication mode is not limited to the setting of the extended range and DCM, but may also be the setting of other communication parameters. As an example, in the setting of the communication mode, setting examples 4 to 7 of the association between the communication mode and the HARQ action when the MCS, the number of STSs, the bandwidth, and the RU allocation are set respectively are described.

[0127] <Setting Example 4>

[0128] In setting example 4, the HARQ action or HARQ type is switched based on the MCS value set for the STA 200 .

[0129] Fig.13 An example of the relationship between the MCS value configured for the STA 200 and the HARQ operation is shown.

[0130] For example, the lower the communication quality of the STA 200, the smaller the MCS value set for the STA 200. Therefore, the smaller the MCS value, the easier it is to improve the communication quality through the HARQ operation and the easier it is to improve the throughput.

[0131] So, for example, in Fig.13 In the HARQ action regulation example 1 shown, when the MCS value is small (for example, any one of MCS0 to MCS4), the HARQ action is set, and when the MCS value is large (for example, any one of MCS5 to MCS11), the HARQ action is not set (non-action). In other words, the HARQ action and non-action are switched based on the MCS value set for STA200.

[0132] In addition, in an environment where the MCS value is set to a small value, the coding gain through the IR and the maximum ratio synthesis gain through the CC are equal. In addition, among HARQ types, the amount of control information in the CC is less than that in the IR. Therefore, Fig.13 As in the HARQ operation definition example 2 shown, when the MCS value is small (for example, when the MCS value is equal to or less than a threshold), by setting the HARQ type to CC, it is possible to reduce overhead and improve throughput.

[0133] On the other hand, in an environment where the MCS value is set to a larger value, the coding gain through IR is greater than the maximum ratio synthesis gain through CC. Fig.13 As in the HARQ operation definition example 2 shown in FIG. 1 , when the MCS value is large (for example, any one of MCS5 to MCS11), the HARQ type is set to IR.

[0134] <Setting Example 5>

[0135] In setting example 5, the HARQ operation or the HARQ type is switched based on the number of STSs set for the STA 200 .

[0136] Fig.14 An example of the relationship between the number of STSs configured for the STA 200 and the HARQ operation is shown.

[0137] For example, the lower the communication quality of the STA 200, the smaller the number of STSs set for the STA 200. Therefore, the smaller the number of STSs, the easier it is to improve the communication quality through the HARQ operation and the easier it is to improve the throughput.

[0138] So, for example, in Fig.14 In the HARQ action regulation example 1 shown, when the number of STSs is small (for example, the number of STSs is any one of 1 to 4), the HARQ action is set, and when the number of STSs is large (for example, the number of STSs is any one of 5 to 16), the HARQ action is not set (non-action).

[0139] In addition, in an environment where the number of STSs is set to be small, the coding gain through IR and the maximum ratio synthesis gain through CC are equal. In addition, among HARQ types, the amount of control information in CC is less than that in IR. Therefore, Fig.14 As in the HARQ operation definition example 2 shown in the figure, when the number of STSs is small (for example, when the number of STSs is equal to or less than a threshold), by setting the HARQ type to CC, it is possible to reduce overhead and improve throughput.

[0140] On the other hand, in an environment where the number of STSs is set to be large, the coding gain through IR is greater than the maximum ratio synthesis gain through CC. Fig.14 As in the HARQ operation definition example 2 shown in the figure, when the number of STSs is large (for example, when the number of STSs is any one of 5 to 16), the HARQ type is set to IR.

[0141] <Setting Example 6>

[0142] In setting example 6, the HARQ operation or the HARQ type is switched based on the bandwidth set for the STA 200 .

[0143] Fig.15 An example of the relationship between the bandwidth configured for the STA 200 and the HARQ operation is shown.

[0144] For example, the lower the communication quality of the STA 200, the narrower the bandwidth set for the STA 200. Therefore, the narrower the bandwidth, the easier it is to improve the communication quality through the HARQ operation and the easier it is to improve the throughput.

[0145] So, for example, in Fig.15 In the HARQ action regulation example 1 shown, the HARQ action is set when the bandwidth is narrow (for example, the bandwidth is 20 MHz or 40 MHz), and the HARQ action is not set (non-action) when the bandwidth is wide (for example, the bandwidth is 80 MHz or more).

[0146] In addition, in an environment where the bandwidth is set to be narrow, the coding gain through IR and the maximum ratio synthesis gain through CC are equal. In addition, among HARQ types, the amount of control information of CC is less than that of IR. Therefore, Fig.15 As in the HARQ operation definition example 2 shown in the figure, when the bandwidth is narrow (for example, when the bandwidth is equal to or less than a threshold), by setting the HARQ type to CC, it is possible to reduce overhead and improve throughput.

[0147] On the other hand, in a high-quality environment where the bandwidth is set wide, the coding gain through IR is greater than the maximum ratio synthesis gain through CC compared to a low-quality environment. Fig.15 As shown in the HARQ operation definition example 2, when the bandwidth is wide (for example, when the bandwidth is 80 MHz or more), the HARQ type is set to IR.

[0148] <Setting Example 7>

[0149] In setting example 7, the HARQ action or HARQ type is switched based on the RU size allocated to the STA 200 .

[0150] Fig.16 An example of the association between the RU size (for example, the number of tones) allocated to the STA 200 and the HARQ action is shown.

[0151] For example, the lower the communication quality of the STA 200, the smaller the RU size allocated to the STA 200. Therefore, the smaller the RU size, the easier it is to improve the communication quality through the HARQ operation and the easier it is to improve the throughput.

[0152] So, for example, in Fig.16 In the HARQ action regulation example 1 shown, when the RU size is small (for example, when the number of tones is less than 242 tones), the HARQ action is set, and when the RU size is large (for example, when the number of tones is greater than 484 tones), the HARQ action is not set (non-action).

[0153] In addition, in an environment where the RU size is set to be small, the coding gain through the IR and the maximum ratio synthesis gain through the CC are equal. In addition, among the HARQ types, the amount of control information in the CC is less than that in the IR. Therefore, Fig.16 As shown in the HARQ action definition example 2, when the RU size is small (for example, when the RU size is equal to or smaller than a threshold), by setting the HARQ type to CC, it is possible to reduce overhead and improve throughput.

[0154] On the other hand, in an environment where the RU size is set large, the coding gain through IR is greater than the maximum ratio synthesis gain through CC. Fig.16 As shown in the HARQ action definition example 2, when the RU size is large (for example, when the number of tones is 484 tones or more), the HARQ type is set to IR.

[0155] In the above, a setting example of the association between the communication mode setting and the HARQ operation has been described.

[0156] In addition, the above-mentioned parameters related to the communication mode (e.g., the type, value or range of the communication mode, etc.) and the association between the parameters related to the communication mode and the HARQ action are examples, and are not limited to these examples. For example, the parameters related to the communication mode may also be other parameters that vary according to the communication quality in STA200.

[0157] [AP and STA operation example]

[0158] Fig.17 is a timing diagram showing an example of the operation of the wireless communication system. Fig.17 In the description, as an example, a case where the communication quality in STA200 is high (for example, a state where the communication quality is greater than a threshold value) is described.

[0159] exist Fig.17 , STA200 sends a signal indicating the communication quality in STA200 to AP100 ( Fig.17 The communication quality information (ST101a) of the communication quality (high quality) is displayed.

[0160] The AP 100 determines the communication mode for the STA 200 (for example, setting at least one of extended range and DCM) based on the communication quality of the STA 200 (ST102a). Fig.17 In FIG. 1 , since the communication quality of the STA 200 is high, the AP 100 determines not to set both the extended range and the DCM (in other words, the operation of the extended range and the DCM: OFF).

[0161] In addition, the AP 100 determines the HARQ action (in other words, performs an action decision) based on the result of the communication mode decision (for example, the communication mode setting) for the STA 200 (ST103a). Fig.17 In the example, since it is determined that the extended range and DCM as one of the communication modes are not set, the AP 100 determines that the HARQ action is not set (in other words, HARQ action: OFF) (for example, see Fig.10 , Fig.11 or Fig.12 ).

[0162] Furthermore, the state in which the HARQ action is not configured refers to, for example, a state in which transmission packets are transmitted and received using a PPDU format that does not include HARQ control information or a PPDU format that includes information that explicitly indicates that the HARQ action is not configured.

[0163] In addition, the HARQ control information may include, for example, information indicating either initial transmission or retransmission, information indicating a HARQ type (eg, CC or IR), information indicating a redundancy version (RV), a HARQ process number, or an NDI.

[0164] exist Fig.17 In the embodiment, AP100 transmits a transmission packet to STA200, for example, based on a PPDU format other than the ER PPDU format (ST104a). For example, a transmission packet in a PPDU format other than the ER PPDU format may include DCM setting information indicating that DCM is OFF. In addition, for example, a transmission packet in a PPDU format other than the ER PPDU format does not include HARQ control information.

[0165] Fig.17 As an example of a PPDU format other than the ER PPDU format, a single user (SU) PPDU format is shown. The EHT-SIG-A in the SU PPDU format is composed of, for example, SIG-A1 and SIG-A2.

[0166] For example, Fig.18 As shown, SIG-A1 and SIG-A2 include fields including parameters related to MCS, DCM, bandwidth, NSTS (Number of Space Time Streams), midamble period, and STBC.

[0167] like Fig.18 As shown, in PPDU formats other than the ER PPDU format, when DCM is not in operation (in Fig.18 In the case of "DCM field: 0 setting" shown in the figure), the bits allocated to each field in the PPDU format are used respectively. In other words, when DCM is not in operation, there are no unused bits in each field in the PPDU format other than the ER PPDU format.

[0168] In addition, here, the case where both the extended range and DCM are not set (non-operation case) is described, but the present invention is not limited to this. For example, the settings of the extended range and DCM may be determined independently based on the communication quality, or may be determined in conjunction with each other. Fig.17In the example, the case where the HARQ action is determined based on the setting of the extended range and DCM is described, but the present invention is not limited thereto. The AP 100 may also determine the HARQ action based on parameters related to communication quality (e.g., MCS, number of STSs, bandwidth, or RU allocation) (e.g., see Figure 13 to Figure 16 any one of ).

[0169] exist Fig.17 In the example, STA200 determines the communication mode and HARQ action based on the PPDU format type (e.g., SIG-A2 constellation diagram) of the transmission packet sent from AP100 or the DCM setting information contained in the transmission packet (ST105a). Fig.17 In the example, STA200 determines the non-action of the range extension and DCM. Fig.17 For example, STA200 decides to set the HARQ action to OFF based on the non-action of the extended range and DCM.

[0170] The AP 100 and the STA 200 communicate according to the operation determined regarding the communication mode (eg, extended range and DCM) and the HARQ operation (not shown).

[0171] Next, Fig.19 is a timing diagram showing another example of the operation of the wireless communication system. Fig.19 In the description, as an example, a case where the communication quality in STA200 is low (for example, a state where the communication quality is less than a threshold) is described.

[0172] exist Fig.19 , STA200 sends a signal indicating the communication quality in STA200 to AP100 ( Fig.19 The communication quality information (ST101b) of the communication quality of the device is low quality (medium quality).

[0173] The AP 100 determines the communication mode (for example, the setting (ON or OFF) of at least one of the extended range and the DCM) for the STA 200 based on the communication quality of the STA 200 (ST102b). Fig.19 In FIG. 1 , since the communication quality of the STA 200 is low, the AP 100 determines to set both the extended range and the DCM (in other words, the operation of the extended range and the DCM: ON).

[0174] In addition, AP100 determines the HARQ action (in other words, performs action determination) based on the result of the determination of the communication mode of STA200 (for example, the setting of the communication mode (ON or OFF)) (ST103b). Fig.19In the example, since it is determined that the extended range and DCM are set as one of the communication modes, the AP 100 determines that the HARQ action is set (in other words, the HARQ action: ON) (for example, see Fig.10 , Fig.11 or Fig.12 ).

[0175] In addition, the state in which the HARQ action is set refers to, for example, a state in which a transmission packet is transmitted and received using a PPDU format including HARQ control information or a PPDU format including information that explicitly indicates that the HARQ action is being performed.

[0176] In addition, the HARQ operation is not limited to being associated with both the extended range and DCM settings, and may be associated with either the extended range or DCM settings, or may be associated with other parameters related to communication quality.

[0177] exist Fig.19 In the example, AP100 transmits a transmission packet to STA200 based on the ER PPDU format (e.g., also referred to as "ER-HARQ PPDU format") (ST104b). For example, the transmission packet in the ER PPDU format may include DCM setting information indicating that DCM is ON. In addition, for example, the transmission packet in the ER PPDU format may include HARQ control information.

[0178] Fig.19 In the figure, an extended range operation is shown, and as an example of a PPDU format including HARQ control information, an ER-HARQ PPDU format is shown. The EHT-SIG-A in the ER-HARQ PPDU format is composed of, for example, SIG-A1, SIG-A2, SIG-A3, and SIG-A4. For example, SIG-A2 is a repetition of SIG-A1, and SIG-A4 is a repetition of SIG-A3.

[0179] For example, Fig. 20 As shown, SIG-A1 (or SIG-A2) and SIG-A3 (or SIG-A4) include fields including parameters related to MCS, bandwidth, NSTS (number of space-time streams), and midamble period, etc.

[0180] like Fig. 20 As shown in FIG. 1 , in the extended range operation, the MCS is set to one of MCS0, MCS1, and MCS2, the bandwidth is set to 242 tones or 106 tones, and the number of STSs is set to 1. Fig. 20In the extended range operation, a portion of the bits allocated to the fields of each parameter (such as MCS, bandwidth or NSTS and midamble period) is used. In other words, in the extended range operation, there are unused bits in each field in the ER PPDU format.

[0181] Therefore, in this embodiment, for example, HARQ-related signaling (eg, HARQ control information) may be defined in a portion of or all of the bits that are not used in the extended range operation in each field within the ER PPDU format.

[0182] For example, Fig. 20 As shown, in the MCS field, when B19 of the bandwidth field is 0 in the extended range operation (in other words, when a 242-tone RU is allocated), the MCS can be defined in 2 bits of B3-B4 among the 4 bits of B3-B6, and the HARQ-related signaling can be defined in the remaining 2 bits of B5-B6. In addition, for example, Fig. 20 As shown, in the MCS field, when B19 of the bandwidth field is 1 during the extended-range operation (in other words, when the upper frequency 106-tone RU is allocated), MCS can be defined in 1 bit of B3 among the 4 bits of B3-B6, and HARQ-related signaling can be defined in the remaining 3 bits of B4-B6.

[0183] In addition, for example, Fig. 20 As shown, in the bandwidth field, in the extended range operation, the bandwidth (242 tone or 106 tone) can be defined in one bit of B19 among the two bits of B19-B20, and the HARQ-related signaling can be defined in the remaining one bit of B20.

[0184] In addition, for example Fig. 20 As shown, in the NSTS and midamble period fields, when the range-extending operation is in progress, when the Doppler field is 0, among the 3 bits of B23-B25, the STS number is defined in 1 bit of B23, and the HARQ-related signaling is defined in the remaining 2 bits of B24-B25. In addition, for example, Fig. 20 As shown, in the NSTS and intermediate code period fields, when the range-extending action is performed, when the Doppler field is 1, among the 3 bits of B23-B25, the STS number is defined in 1 bit of B23, the intermediate code period is defined in 1 bit of B25, and the HARQ-associated signaling is defined in the remaining 1 bit of B24.

[0185] In addition, Fig.19In the embodiment, instead of the ER-HARQ PPDU format, for example, a PPDU format indicating a DCM action and including HARQ control information (for example, a DCM-HARQ PPDU format) may be applied. Fig.19 As shown, the EHT-SIG-A in the DCM-HARQ PPDU format includes, for example, SIG-A1 and SIG-A2.

[0186] For example, Fig.21 As shown, SIG-A1 and SIG-A2 include fields including parameters related to MCS, DCM, bandwidth, NSTS and midamble period, and STBC, etc.

[0187] like Fig.21 As shown in FIG. 1 , when DCM is in operation, MCS is set to any one of MCS0, MCS1, MCS3, and MCS4, and the number of STS is set to 1 or 2. In addition, when DCM is in operation, the combination of DCM and STBC is not applied. Fig.21 In the DCM operation, a portion of the bits allocated to the fields of each parameter (such as MCS, NSTS, midamble period, and STBC) is used. In other words, in the extended range operation, there are unused bits in each field in the PPDU format.

[0188] Therefore, in this embodiment, for example, HARQ-related signaling (for example, HARQ control information) may be defined in a part of or all of the bits that are not used in the DCM operation in each field within the PPDU format.

[0189] For example, Fig.21 As shown, in the MCS field, when DCM is in operation, MCS can be defined in 3 bits of B3-B5 among the 4 bits of B3-B6, and HARQ-related signaling can be defined in the remaining 1 bit of B6.

[0190] In addition, for example, Fig.21 As shown, in the NSTS and intermediate code period fields, when DCM is in action, the STS number can be defined in 1 bit of B23 among the 3 bits of B23-B25, and the HARQ-related signaling can be defined in the remaining 2 bits of B24-B25.

[0191] In addition, for example, Fig.21 As shown, in the STBC field, when DCM is in operation, HARQ-related signaling can be defined in one bit of B9 that is not used when DCM is in operation.

[0192] exist Fig.19In the example, STA200 determines the communication mode and HARQ action based on the PPDU format type (e.g., SIG-A2 constellation diagram) of the transmission packet sent from AP100 or the DCM setting information contained in the transmission packet (ST105b). Fig.19 In the example, STA200 determines the action (ON) of the range extension and DCM. Fig.19 For example, STA200 determines the HARQ action to be ON based on the extended range and DCM actions (ON).

[0193] The AP 100 and the STA 200 communicate according to the operation determined regarding the communication mode (eg, extended range and DCM) and the HARQ operation (not shown).

[0194] In the above, the operation examples of the AP 100 and the STA 200 have been described.

[0195] In addition, Fig.17 and Fig.19 In the description, the case where the settings of both the extended range and the DCM are associated with the HARQ operation is described, but the present invention is not limited thereto, and the settings of either the extended range or the DCM may be associated with the HARQ operation.

[0196] In addition, Fig.17 and Fig.19 In the description, the case where the ON and OFF of the HARQ action is determined based on the communication mode (in other words, the communication quality) is described. However, the content of the determination of the HARQ operation is not limited to the action or non-action of the HARQ, and may be, for example, the HARQ type (eg, CC or IR).

[0197] As described above, according to the present embodiment, AP100 determines the HARQ action based on the communication mode (in other words, communication parameters) set according to the communication quality of STA200. For example, AP100 determines at least one of the HARQ action and the HARQ type (for example, CC or IR) based on the setting of the communication mode (for example, at least one of extended range and DCM). In addition, STA200 performs the HARQ action determined based on the communication mode of STA200, for example.

[0198] As a result, the STA 200 can perform the HARQ operation according to the communication quality of the STA 200, so that the throughput can be improved. Therefore, according to the present embodiment, the efficiency of the HARQ control can be improved according to the communication quality.

[0199] In addition, in this embodiment, for example, HARQ control information is defined in bits that are not used when the extended range or DCM operation is in progress (in other words, when the communication mode is set). This suppresses the increase in signaling from AP 100 to STA 200 and enables HARQ control-related signaling.

[0200] In addition, in this embodiment, the case where communication quality is classified into two types, high quality and low quality, is described, but communication quality may be classified into three or more types. For example, HARQ actions (e.g., action or non-action, or HARQ type) may be associated with three or more communication qualities.

[0201] In addition, for example, in the extended range action, such as Figure 2 As shown, in the constellation diagram of SIG-A2, by applying the QBPSK signal obtained by rotating the phase of the BPSK signal by 90 degrees, STA200 can identify whether it is an extended range PPDU format (for example, ER SU PPDU) before decoding SIG-A. In this embodiment, the QBPSK signal can be further applied to at least one of the constellations of SIG-A3 and SIG-A4. As a result, AP100 can, for example, implicitly notify STA200 of HARQ control information.

[0202] For example, Fig. 22 As shown in FIG. 1 , there are three combinations of applying QBPSK to at least one of the constellations of SIG-A3 and SIG-A4. Therefore, for example, the AP 100 can make the constellations of SIG-A3 and SIG-A4 notified to the STA 200 different between new transmission and retransmission. Thus, the STA 200 can also recognize the initial transmission and retransmission of HARQ based on the presence or absence of QBPSK in the constellations of SIG-A3 and SIG-A4.

[0203] In addition, for example, a combination of constellation diagrams in a plurality of areas (e.g., SIG-A3 and SIG-A4 fields) to which information notified to STA200 is allocated may be associated with HARQ control information (e.g., HARQ type (CC or IR), RV, HARQ process number, or NDI). For example, STA200 may be based on a combination of QBPSK in the constellation diagrams of SIG-A3 and SIG-A4 ( Fig. 22 Any one of Examples 1 to 3 shown), for example, identifying the HARQ type (CC or IR), RV, HARQ process number or NDI.

[0204] like Fig. 22 As shown, by associating the constellation diagram of SIG-A with the HARQ control information, the signaling for notifying the HARQ control information can be reduced.

[0205] In addition, Fig.17 ST104a processing or Fig.19 In the processing of ST104b of , the number of bits available for HARQ-related signaling (or HARQ control information) is different in the extended range operation and the DCM operation (for example, see Fig. 20 and Fig.21 ). Therefore, for example, the content of HARQ-related signaling (for example, the RV mode and the number of HARQ processes, etc.) can be made different during extended range operation and DCM operation.

[0206] In addition, the communication mode serving as a reference for determining the HARQ operation is not limited to the extended range and DCM, and may be, for example, a communication mode indicating whether the MCS, the number of STSs, the bandwidth, or the STBC is restricted.

[0207] In addition, Fig.17 and Fig.19 In the description, the structure of HE-SIG-A defined in IEEE 802.11ax is described as an example, but the format of the transmitted packet is not limited to this structure and may also be the structure of other signaling.

[0208] (Implementation Method 2)

[0209] In Embodiment 1, a method of determining the HARQ operation based on the communication mode (in other words, communication parameters) is described. In contrast, in this embodiment, a method of determining the communication mode (in other words, communication parameters) based on the HARQ operation is described.

[0210] The wireless communication system of this embodiment includes at least one AP 300 and at least one STA 400 .

[0211] Fig.23 is a block diagram showing a configuration example of AP300 according to this embodiment. Fig.23 In the embodiment 1 ( Figure 8 ) The same structure is assigned the same label and its description is omitted.

[0212] exist Fig.23 In the example, the control unit 301 determines the HARQ action (ON or OFF) for the STA 400. The control unit 301 can determine the HARQ action based on the information related to the communication quality of the STA 400 input from the reception packet decoding unit 106. The control unit 301 outputs the information related to the HARQ action (for example, ON or OFF) to the transmission packet generation unit 101.

[0213] Thus, information indicating the HARQ action is notified from the AP 300 to the STA 400. In addition, information related to the determination of the HARQ action can be transmitted and received between the AP 300 and the STA 400 through, for example, a MAC frame.

[0214] In addition, the control unit 301 determines the communication mode (for example, at least one of extended range and DCM) for the STA 400 based on the HARQ operation. In addition, an example of a method for determining the communication mode based on the HARQ operation will be described later.

[0215] In addition, the control unit 301 determines the communication parameters set for the STA 400 based on information related to the communication parameters (or also "recommended communication parameters") fed back from the STA 400, which is input from the received packet decoding unit 106. The control unit 301 outputs the determined communication parameters to the transmission packet generation unit 101. Thereby, the transmission packet generation unit 101 generates a transmission packet according to the determined communication parameters.

[0216] The communication parameter request unit 302 generates a message for requesting communication parameters to the STA 400. The communication parameter request unit 302 outputs the generated communication parameter request message to the transmission packet generation unit 101.

[0217] Thus, the communication parameter request message is notified from the AP 300 to the STA 400. In addition, the communication parameters may include, for example, MCS, STS number (eg, NSTS), bandwidth, or STBC action.

[0218] Fig.24 is a block diagram showing a configuration example of STA400 according to this embodiment. Fig.24 In the embodiment 1 ( Fig. 9 ) The same structure is assigned the same label and its description is omitted.

[0219] The control unit 401, for example, determines a HARQ action (for example, ON or OFF) for the STA 400. The control unit 401 may determine the HARQ action based on, for example, the signaling from the AP 300 input from the reception packet decoding unit 206. The control unit 401 outputs information related to the determined HARQ action (for example, ON or OFF) to the transmission packet generation unit 201.

[0220] In addition, the control unit 401 determines a communication mode (for example, at least one of extended range and DCM) for the STA 400 based on the HARQ operation. In addition, an example of a method for determining a communication mode based on the HARQ operation will be described later.

[0221] When receiving the communication parameter request message from the reception packet decoder 206 , the communication parameter determiner 402 determines the communication parameters (in other words, recommended communication parameters) based on, for example, the communication quality between the AP 300 and the STA 400 . The communication parameter determiner 402 outputs the determined recommended communication parameters to the transmission packet generator 201 .

[0222] As a result, the communication parameters are fed back from the STA 400 to the AP 300 .

[0223] Furthermore, the communication parameter determination unit 402 may measure the communication quality based on the demodulated signal input from the demodulation unit 205. Information related to the communication quality includes, for example, SNR, the communication distance between the AP 300 and the STA 400, propagation loss, interference amount, error rate, and the like.

[0224] [Relationship between HARQ operation and communication mode]

[0225] Next, the relationship between the HARQ operation and the communication mode according to the present embodiment will be described.

[0226] Here, as an example, the association between the communication mode and the HARQ action in which at least one of the extended range and DCM is set is described. The AP 300 and the STA 400 determine the communication mode for the STA 400 based on the association between the communication mode and the HARQ action and the HARQ action set for the STA 400 (eg, ON or OFF).

[0227] Hereinafter, setting examples 1 to 3 of the association between the HARQ operation and the communication mode will be described respectively.

[0228] <Setting Example 1>

[0229] Fig.25 An example of association between the HARQ action (ON or OFF) of setting example 1 and the setting of the extended range or DCM (for example, action or non-action) is shown.

[0230] exist Fig.25 In the case where HARQ is in operation (eg, ON), the extended range and DCM are set (extended range and DCM: in operation), and in the case where HARQ is not in operation (eg, OFF), the extended range and DCM are not set (extended range and DCM: inactive).

[0231] Thus, for example, when it is determined that the communication environment of STA400 is poor (for example, when the communication quality is below a threshold value), when HARQ is to be operated, both the extended range and DCM are operated. Therefore, in addition to the HARQ operation, the communication quality of STA400 can be improved by the operation of the extended range and DCM, and the throughput can be improved.

[0232] <Setting Example 2>

[0233] Fig.26 This is an example of the association between the HARQ action (ON or OFF) of setting example 2 and the setting of the extended range or DCM (for example, action or non-action).

[0234] exist Fig.26 In the case of HARQ operation (for example, ON), the extended range is set (extended range: operation), and the DCM is not set (DCM: non-operation). Fig.26 In the case where HARQ is not in operation (for example, OFF), the extended range and DCM are not set (extended range and DCM: non-operation).

[0235] Thus, for example, when it is determined that the communication environment of STA400 is poor (for example, when the communication quality is below a threshold), the extended range operation is performed when HARQ is to be performed. Therefore, in addition to the HARQ operation, the extended range operation can improve the communication quality of STA400 and the throughput.

[0236] Furthermore, Setting Example 2 can be applied, for example, when there is no need to improve communication quality by DCM or when the STA 400 does not support DCM.

[0237] <Setting Example 3>

[0238] Fig. 27 An example of association between the HARQ action (ON or OFF) of setting example 3 and the setting of the extended range or DCM (for example, action or non-action) is shown.

[0239] exist Fig. 27 In the case of HARQ operation (for example, ON), DCM is set (DCM: operation), and extended range is not set (extended range: non-operation). Fig. 27 In the case where HARQ is not in operation (for example, OFF), the extended range and DCM are not set (extended range and DCM: non-operation).

[0240] Thus, for example, when the communication environment of STA400 is judged to be poor (for example, when the communication quality is below a threshold value), DCM is activated when HARQ is to be activated. Therefore, in addition to HARQ, DCM can improve the communication quality of STA400 and the throughput.

[0241] Furthermore, the setting example 3 can be applied, for example, when there is no need to improve the communication quality by increasing the range or when the STA 400 does not support the increasing range.

[0242] In the above, setting examples 1 to 3 have been described.

[0243] By defining the association between HARQ actions and communication modes, for example, the communication mode settings (action or inaction) such as extended range and DCM are uniquely determined based on the HARQ actions (for example, action or inaction). Therefore, signaling related to communication mode determination can be reduced.

[0244] In addition, Figure 25 to Figure 27 , the association between the HARQ action and the setting of the extended range and DCM is described, but the communication mode (or communication parameter) associated with the HARQ action is not limited thereto. For example, the HARQ action may also be associated with other communication parameters (e.g., MCS, number of STSs, bandwidth, and RU allocation, etc.).

[0245] In addition, the HARQ action content is not limited to the HARQ action, and may be a HARQ type (for example, any one of CC and IR), for example, the HARQ type may be associated with a communication mode (for example, extended range, DCM, MCS, number of STSs, bandwidth, and RU allocation, etc.). For example, when the HARQ type is CC, at least one of the extended range and DCM may be enabled, and when the HARQ type is IR, the extended range and DCM may not be enabled.

[0246] [AP and STA operation example]

[0247] Next, an operation example of the AP 300 and the STA 400 according to the present embodiment will be described.

[0248] Fig.28 This is a sequence diagram showing an example of the operation of the wireless communication system.

[0249] exist Fig.28 In the present invention, the AP 300 and the STA 400 determine the HARQ operation (eg, ON or OFF) (ST201). The AP 300 and the STA 400 may determine the HARQ action, for example, through signaling in the MAC frame.

[0250] For example, during association (in other words, connection request response), AP 300 and STA 400 exchange information related to STA 400 (eg, capability information). For example, AP 300 may also determine HARQ action (ON / OFF) based on information related to STA 400 and communication quality.

[0251] An example of a method for determining HARQ action may also be a method based on the number of STAs connected to AP300. For example, the more STAs connected to AP300, the more multiplexing numbers of Orthogonal Frequency Division Multiple Access (OFDMA) or Multi User-Multiple Input Multiple Output (MU-MIMO). Therefore, the more STAs connected to AP300, the more the amount of signaling sent in one packet increases when the HARQ information of each multiplexed STA is aggregated and notified. Therefore, for example, AP300 can determine that there is HARQ action when the number of STAs connected to AP300 is small (for example, less than a threshold), and can determine that there is no HARQ action when the number of STAs connected to AP300 is large (for example, above the threshold). In this method, when the number of STAs connected to AP300 is large, by determining that there is no HARQ action, the increase in the amount of signaling can be suppressed.

[0252] In addition, another example of a method for determining HARQ actions is a method based on the error rate of received packets. For example, when the error rate of received packets is less than a threshold, AP300 may determine that there is no HARQ action, and when the error rate of received packets is greater than the threshold, it may determine that there is HARQ action. Since the lower the error rate of received packets, the smaller the effect of improving communication quality through HARQ actions, by determining that there is no HARQ action, the increase in the amount of signaling can be suppressed.

[0253] In addition, the method of determining the HARQ action is not limited to these methods, and other methods may be used.

[0254] exist Fig.28 In the example, AP300 and STA400 determine the communication mode of STA400 based on the HARQ action (ST202 and ST203). Fig.25 , Fig.26 and Fig. 27 The association between the HARQ action shown in any one of the settings and the communication mode (here, extended range and DCM) and the determined HARQ action (ON or OFF) determine the setting of the communication mode.

[0255] The AP 300 transmits a message requesting communication parameters to the STA 400 ( ST204 ).

[0256] In response to the communication parameter request transmitted from AP 300 , STA 400 feeds back the recommended communication parameters to AP 300 ( ST205 ).

[0257] The AP 300 determines the communication parameters to be set for communication with the STA 400 based on the recommended communication parameters fed back from the STA 400 , and transmits data to the STA 400 based on the determined communication parameters ( ST206 ).

[0258] Furthermore, when determining the communication parameters to be notified to the STA 400 , the AP 300 may change the definition of the communication parameters based on the HARQ action (ON or OFF).

[0259] Here, as an example, a case where the communication parameters include MCS, the number of STSs, bandwidth, and STBC operation will be described. Fig.29 This is an example of the definition of the communication parameters when the HARQ action is not set (HARQ action: OFF). Fig.30 This shows an example of the definition of the communication parameters when the HARQ operation is set (HARQ operation: ON).

[0260] like Fig.29 As shown, when the HARQ action is not set, the bits allocated to MCS, STS number, bandwidth and STBC are used (or reserved). In other words, when the HARQ action is not set, there are no unused bits (or no unreserved bits) among the bits allocated to MCS, STS number, bandwidth and STBC.

[0261] On the other hand, for example, in an environment where the communication quality of the HARQ action is poor (for example, an environment where the communication quality is below the threshold), the requested communication quality may not be ensured within all setting ranges of the communication parameters. Therefore, for example, in the case of the HARQ action, the communication parameters set for the STA 400 may be partial values ​​that can ensure the requested communication quality within the setting range. In other words, in the case of the HARQ action, the setting range of the communication parameters is limited to a part.

[0262] For example Fig.30 As shown in FIG. 1 , when the HARQ action is set, the range of parameters set in MCS, number of STSs, bandwidth, and STBC becomes narrower than when the HARQ action is not set. Fig.30 As shown, when the HARQ action is set, the number of bits allocated to MCS, the number of STSs, the bandwidth, and STBC may be reduced, and the remaining bits may be used to define HARQ-related signaling.

[0263] In other words, for bits to which information to be notified to STA 400 is allocated, parameters defined when the HARQ action is set (for example, see Fig.30) and the parameters defined when the HARQ action is not set (see, for example, Fig.29 )different.

[0264] For example, Fig.30 Among the 4 bits of MCS, HARQ-associated signaling is defined by 2 bits, among the 4 bits of STS number (for example, NSTS-1), HARQ-associated signaling is defined by 3 bits, among the 3 bits of bandwidth, HARQ-associated signaling is defined by 2 bits, and HARQ-associated signaling is defined by 1 bit of STBC.

[0265] also, Fig.30 The combination (defined combination) of each communication parameter and the content of HARQ associated signaling (e.g., transmission type, HARQ type, RV, HARQ process number, etc.) shown in is an example and is not limited to this. In addition, the content of HARQ associated signaling associated with each communication parameter is not limited to Fig.30 Parameters shown in .

[0266] As described above, according to this embodiment, AP300 and STA400 determine the setting of the communication mode for STA400 based on the HARQ action for STA400. As a result, since STA400 can perform HARQ action according to the communication quality of STA400, the throughput can be improved. Therefore, according to this embodiment, the efficiency of HARQ control can be improved according to the communication quality.

[0267] In addition, in this embodiment, the communication parameters defined in each bit in the signaling notified from AP300 to STA400 are switched based on the HARQ action. In this case, for example, HARQ control information (in other words, HARQ-related signaling) is defined by bits that are not used during the HARQ action. As a result, the increase in signaling from AP300 to STA400 is suppressed, and HARQ control-related signaling is enabled.

[0268] (Implementation method 3)

[0269] For example, there is a link adaptation function that adaptively changes communication parameters such as MCS according to the communication environment of the STA.

[0270] In link adaptation, for example, the AP sends a message (for example, MCS Request (MCS Request: MRQ)) to the STA for requesting MCS (in other words, recommending MCS). Based on the MRQ, the STA feeds back a message (for example, MCS Feedback (MCS Feedback: MFB)) including an MCS corresponding to the communication quality (for example, called "recommended MCS") to the AP.

[0271] In this embodiment, a case where information related to HARQ control is included in one of the communication parameters adaptively changed by link adaptation will be described.

[0272] The wireless communication system of this embodiment includes at least one AP and at least one STA.

[0273] Fig.31 This is a sequence diagram showing an example of the operation (eg, link adaptation) of the wireless communication system.

[0274] exist Fig.31 In the process, the AP transmits a message for requesting communication parameters to the STA 400 (ST301). The message for requesting communication parameters may be, for example, a message for requesting MCS (MRQ) or other messages.

[0275] The requested communication parameters may be, for example, MCS or other communication parameters (e.g., number of STSs, bandwidth, RU allocation, DCM action, etc.) (e.g., see non-patent document 2). In addition, when both the AP and the STA can support HARQ action, for example, the requested communication parameters may include information related to HARQ control.

[0276] The STA feeds back the recommended communication parameters to the AP based on the communication parameter request sent from the AP (ST302). The message for feeding back the recommended communication parameters may be, for example, a message for feeding back the recommended MCS (e.g., MFB), or other messages. The STA may, for example, determine the recommended communication parameters based on the communication quality between the AP and the STA.

[0277] In addition, when both the AP and the STA can support HARQ actions, for example, the recommended communication parameters may include information related to HARQ control. The parameters related to the HARQ action may be, for example, the HARQ action (ON or OFF) or the HARQ type (eg, CC or IR).

[0278] The AP determines the communication parameters (for example, MCS and HARQ operation) to be set for the STA based on the recommended communication parameters fed back from the STA (ST303).

[0279] Then, the AP transmits data to the STA based on the determined communication operation (ST304).

[0280] As described above, in this embodiment, the AP includes information related to the HARQ action in the communication parameters requested by the STA. As a result, the AP can adaptively change the HARQ action according to the communication quality of the STA. Therefore, according to this embodiment, the AP can perform HARQ control based on appropriate communication parameters that are not excessive or insufficient corresponding to the communication quality of the STA.

[0281] In addition, in the present embodiment, for example, by including a message requesting a HARQ operation in a message (for example, MRQ) for requesting a recommended MCS, it is possible to suppress an increase in signaling.

[0282] In addition, this embodiment may also be combined with any one of Embodiments 1 and 2. For example, as described in this embodiment, the AP may determine the HARQ action as shown in Embodiment 1 based on the HARQ action or other parameters (e.g., DCM action, MCS, number of STSs, bandwidth, or RU allocation, etc.) shown in the recommended communication parameters fed back from the STA. Alternatively, as described in this embodiment, the AP may determine the HARQ action based on the HARQ action shown in the recommended communication parameters fed back from the STA, and further determine the communication mode (e.g., at least one of extended range and DCM) based on the HARQ action as shown in Embodiment 2.

[0283] In addition, information related to link adaptation (e.g., signaling) may be sent and received between the AP and the STA, for example, in the MAC layer. In other words, the message for requesting the HARQ action and the recommended communication parameters indicating the HARQ action may be included in a signal in the MAC layer (e.g., also referred to as "MPDU" or "MAC frame", etc.).

[0284] In addition, the message for requesting the HARQ action and the recommended communication parameters indicating the HARQ action are not limited to the MAC layer, but can also be sent and received in other layers (e.g., the physical layer). In addition, among the information related to link adaptation, part of the information can be sent and received in the MAC layer, and the other information can be sent and received in the physical layer.

[0285] In the above, each embodiment of the present disclosure has been described.

[0286] (Other embodiments)

[0287] In the above implementation, as an example, the format based on IEEE 802.11ax is described, but the format of an embodiment of the present disclosure is not limited to the 11ax format. An embodiment of the present disclosure can also be applied to, for example, IEEE802.11be (EHT), the next generation standard for IEEE802.11ax, and IEEE 802.11bd (NGV (Next Generation V2X)), the next generation standard for 802.11p for vehicle-mounted standards.

[0288] Furthermore, at least two of Embodiment 1, Embodiment 2, and Embodiment 3 may be combined and applied.

[0289] Furthermore, in the above-mentioned embodiment, the HARQ operation of the downlink from the AP to the STA is described, but it can also be applied to the uplink from the STA to the AP.

[0290] The present disclosure can be implemented by software, hardware or software in cooperation with hardware. Each functional block used in the description of the above-mentioned embodiment is partially or entirely implemented as an LSI (Large Scale Integration) as an integrated circuit, and each process described in the above-mentioned embodiment can also be partially or entirely controlled by an LSI or a combination of LSIs. LSI can be composed of individual chips, or it can be composed of a chip in a manner that includes part or all of the functional blocks. LSI can also include the input and output of data. LSI can also be called "IC (Integrated Circuit)", "System LSI (System LSI)", "Super LSI (Super LSI)", "Ultra LSI (Ultra LSI)" according to the different integration levels. The method of integrated circuitization is not limited to LSI, and can also be implemented by a dedicated circuit, a general-purpose processor or a dedicated processor. In addition, an FPGA (Field Programmable Gate Array) that can be programmed after LSI manufacturing, or a reconfigurable processor (Reconfigurable Processor) that can reconfigure the connection or setting of the circuit block inside the LSI can also be used. The present disclosure can also be implemented as digital processing or analog processing. Furthermore, if integrated circuit technology that replaces LSI emerges as semiconductor technology advances or other technologies are derived, it is of course possible to use this technology to achieve integration of functional blocks. There is also the possibility of applying biotechnology, etc.

[0291] The present disclosure can be implemented in all kinds of devices, equipment, and systems (collectively referred to as "communication devices") with communication functions. The communication device may also include a wireless transceiver and a processing / control circuit. The wireless transceiver may also include a receiving unit and a transmitting unit, or perform the functions of these parts. The wireless transceiver (transmitting unit, receiving unit) may also include an RF (Radio Frequency) module and one or more antennas. The RF module may also include an amplifier, an RF modulator / demodulator, or a device similar to these. Non-limiting examples of communication devices include telephones (mobile phones, smart phones, etc.), tablet computers, personal computers (PCs) (laptops, desktops, notebook computers, etc.), cameras (digital cameras, digital video cameras, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smart watches, tracking devices, etc.), game consoles, e-book readers, telehealth / telemedicine (telehealth / prescription) equipment, vehicles with communication functions or transportation vehicles (cars, airplanes, ships, etc.) and combinations of the above-mentioned various devices.

[0292] Communication devices are not limited to portable or mobile devices, but also include all kinds of devices, equipment, and systems that cannot be carried or fixed. For example, they include: smart home devices (home appliances, lighting equipment, smart meters or meters, control panels, etc.), vending machines, and all other "things" that can exist on the IoT (Internet of Things) network.

[0293] The communication includes data communication performed by a cellular system, a wireless LAN (Local Area Network) system, a communication satellite system, etc., and also includes data communication performed by a combination of these systems.

[0294] In addition, the communication device also includes devices such as a controller or a sensor connected or linked to the communication device that performs the communication function described in the present disclosure. For example, it includes a controller or a sensor that generates a control signal or a data signal used by the communication device that performs the communication function of the communication device.

[0295] In addition, the communication device includes infrastructure equipment that communicates with the above-mentioned non-limiting various devices or controls the above-mentioned various devices, such as base stations, access points, and all other devices, equipment, and systems.

[0296] A base station according to an embodiment of the present disclosure comprises: a control circuit that determines one of a retransmission control action and a communication parameter set according to communication quality; and a communication circuit that communicates with a terminal based on the determined communication parameter or the retransmission control action.

[0297] In one embodiment of the present disclosure, the control circuit determines the action of the retransmission control based on the communication parameter.

[0298] In one embodiment of the present disclosure, the communication parameter indicates a setting of a communication mode, and the control circuit determines at least one of an action of the retransmission control and a type of the retransmission control based on the setting of the communication mode.

[0299] In one embodiment of the present disclosure, the information related to the retransmission control is defined in a bit that is not used when the communication mode is set, among a plurality of bits used to allocate information notified to the terminal.

[0300] In one embodiment of the present disclosure, when the communication mode is set, the control circuit makes a constellation diagram of information notified to the terminal different between new transmission and retransmission.

[0301] In one embodiment of the present disclosure, a combination of constellation diagrams in a plurality of regions to which information notified to the terminal is allocated is associated with the information related to the retransmission control.

[0302] In one embodiment of the present disclosure, the control circuit determines the communication parameter based on the retransmission control operation.

[0303] In one embodiment of the present disclosure, the communication parameter indicates a setting of a communication mode, and the control circuit determines the setting of the communication mode based on an operation of the retransmission control.

[0304] In one embodiment of the present disclosure, for bits to which information notified to the terminal is allocated, the communication parameters defined when the action of the retransmission control is set are different from the communication parameters defined when the action of the retransmission control is not set.

[0305] In one embodiment of the present disclosure, the control circuit includes information related to the retransmission control in the communication parameters requested to the terminal.

[0306] A terminal according to an embodiment of the present disclosure comprises: a control circuit that determines one of a retransmission control action and a communication parameter set according to communication quality; and a communication circuit that communicates with a base station based on the determined communication parameter or the retransmission control action.

[0307] In one embodiment of the present disclosure, the control circuit includes information related to the retransmission control in the communication parameters requested to the base station.

[0308] A communication method according to an embodiment of the present disclosure includes the following steps: a base station determines one of a retransmission control action and a communication parameter set according to communication quality, and communicates with a terminal based on the determined communication parameter or the retransmission control action.

[0309] A communication method according to an embodiment of the present disclosure includes the following steps: a terminal determines one of a retransmission control action and a communication parameter set according to communication quality, and communicates with a base station based on the determined communication parameter or the retransmission control action.

[0310] The disclosure contents of the specification, drawings and abstract contained in Japanese Patent Application No. 2012-081799 filed on April 23, 2019 are incorporated herein by reference in their entirety.

[0311] Industrial Applicability

[0312] An embodiment of the present disclosure is suitable for use in a wireless communication system.

[0313] Description of Reference Numerals

[0314] 100, 300 AP

[0315] 101, 201 Sending packet generation unit

[0316] 102, 202 Modulation Department

[0317] 103, 203 Wireless transmission and reception unit

[0318] 104, 204 Antenna

[0319] 105, 205 Demodulation Unit

[0320] 106, 206 receiving packet decoding unit

[0321] 107 Communication mode determination unit

[0322] 108HARQ control unit

[0323] 200, 400STA

[0324] 207 Communication Quality Measurement Unit

[0325] 301, 401 Control Department

[0326] 302 Communication parameter request unit

[0327] 402 Communication parameter determination unit.

Claims

1. A base station, comprising: a control circuit that determines activation or deactivation of a frequency diversity transmission scheme configured to transmit information at different frequencies based on whether the operation of the retransmission control is ON or OFF; as well as A communication circuit that performs communication with a terminal using the frequency diversity transmission scheme when the frequency diversity transmission scheme is determined to be activated, and performs communication with the terminal without using the frequency diversity transmission scheme when the frequency diversity transmission scheme is determined to be deactivated.

2. The base station according to claim 1, wherein: The control circuit determines communication parameters of the frequency diversity transmission scheme based on the operation of the retransmission control.

3. The base station according to claim 2, wherein: The communication parameters of the frequency diversity transmission scheme indicate a configuration of a communication mode, and The control circuitry determines the configuration of the communication mode based on the operation of the retransmission control.

4. The base station according to claim 2, wherein: The communication parameters of the frequency diversity transmission scheme defined in bits when the operation of the retransmission control is configured are different from the communication parameters defined in bits to which information to be indicated to the terminal is allocated when the operation of the retransmission control is not configured.

5. The base station according to claim 1, wherein: The control circuit includes the information on the retransmission control in a communication parameter to be requested from the terminal.

6. A terminal, comprising: a control circuit that determines activation or deactivation of a frequency diversity transmission scheme configured to transmit information at different frequencies based on whether the operation of the retransmission control is ON or OFF; as well as A communication circuit that performs communication with a base station using the frequency diversity transmission scheme when the frequency diversity transmission scheme is determined to be activated, and performs communication with the base station without using the frequency diversity transmission scheme when the frequency diversity transmission scheme is determined to be deactivated.

7. The terminal according to claim 6, wherein: The control circuit includes information on the retransmission control in a communication parameter of the frequency diversity transmission scheme to be requested from the base station.

8. A communication method, the communication method comprising: determining, by the base station, based on whether the operation of the retransmission control is ON or OFF, to activate or deactivate a frequency diversity transmission scheme configured to transmit information at different frequencies; in a case where the frequency diversity transmission scheme is determined to be activated, performing, by the base station, communication with the terminal using the frequency diversity transmission scheme, and In case the frequency diversity transmission scheme is determined to be deactivated, the base station performs communication with the terminal without using the frequency diversity transmission scheme.

9. A communication method, the communication method comprising: activating or deactivating a frequency diversity transmission scheme configured to transmit information at different frequencies, determined by the terminal based on whether the operation of the retransmission control is ON or OFF; in a case where the frequency diversity transmission scheme is determined to be activated, performing communication with a base station using the frequency diversity transmission scheme by the terminal, and In case the frequency diversity transmission scheme is determined to be deactivated, communication with the base station is performed by the terminal without using the frequency diversity transmission scheme.

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