Wireless communication apparatus and wireless communication method

Abstract

To provide a radio communication device and a radio communication method capable of appropriately controlling setting of feedback to a plurality of transmission sources.SOLUTION: A wireless communication device includes a reception circuit that receives a plurality of wireless signals transmitted by a plurality of transmission sources, and a control circuit that determines a cooperative scheme to be used by the plurality of transmission sources in downlink cooperative communication from among a plurality of cooperative schemes including two or more of CoordinatedSpatialReuse (CSR), CoordinatedBeamforming (CBF), JointTransmission (JT), and DynamicpointBlanking (DPB) in accordance with reception quality of the plurality of wireless signals, and feeds back feedback information of a type corresponding to the determined cooperative scheme among a plurality of types of feedback information to the transmission sources.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to a wireless communication device and a wireless communication method. [Background technology]

[0002] The technical specifications for 802.11be (hereinafter referred to as "11be") are currently being developed as the successor standard to 802.11ax (hereinafter referred to as "11ax"), the IEEE (Institute of Electrical and Electronics Engineers) 802.11 standard.

[0003] In 11be, application of cooperative communication in which a plurality of wireless communication control devices on the data transmitting side cooperate to transmit data to a wireless communication device on the receiving side is being considered. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] IEEE 802.11-19 / 0103r1, AP Coordination in EHT, 2019-03-11 [Non-patent document 2] NTT DOCOMO Technical Journal Vol.21 No.2, Heterogeneous Network Capacity Expansion Technology for LTE / LTE-Advanced, Jul.2013 [Non-patent document 3] IEEE 802.11-19 / 0448r1, Multi-AP Transmission Procedure, 2019-03-11 [Non-patent document 4] IEEE P802.11ax / D4.0, February 2019 Summary of the Invention

[0005] However, feedback information in cooperative communication has not been fully studied.

[0006] Non-limiting embodiments of the present disclosure contribute to providing a wireless communication device and a wireless communication method that can appropriately control feedback settings for multiple transmission sources.

[0007] A wireless communication device according to one embodiment of the present disclosure includes a receiving circuit that receives multiple wireless signals transmitted from multiple transmission sources, and a control circuit that determines a cooperation method to be used by the multiple transmission sources in downlink cooperative communication from multiple cooperation methods including two or more of Coordinated Spatial Reuse (CSR), Coordinated Beamforming (CBF), Joint Transmission (JT), and Dynamic point Blanking (DPB) depending on the reception quality of the multiple wireless signals, and feeds back to the transmission source feedback information of a type corresponding to the determined cooperation method from among multiple types of feedback information.

[0008] These comprehensive or specific aspects may be realized as a system, an apparatus, a method, an integrated circuit, a computer program, or a recording medium, or may be realized as any combination of a system, an apparatus, a method, an integrated circuit, a computer program, and a recording medium.

[0009] According to an embodiment of the present disclosure, feedback settings for multiple transmission sources can be appropriately controlled.

[0010] Further advantages and benefits of an embodiment of the present disclosure will become apparent from the specification and drawings. Such advantages and / or benefits may be provided by some of the embodiments and features described in the specification and drawings, respectively, but not necessarily all of them may be provided to obtain one or more identical features. [Brief explanation of the drawings]

[0011] [Figure 1] An example of a cooperative method [Figure 2]FIG. 1 is a diagram showing an example of a signal transmission / reception sequence; [Figure 3] A diagram showing an example of feedback information specified in IEEE 802.11ax [Figure 4] FIG. 1 is a block diagram showing an example of the configuration of a portion of a wireless communication control device; [Figure 5] A block diagram showing an example of the configuration of a part of a wireless communication device. [Figure 6] FIG. 1 is a diagram showing an example of a sequence of transmitting and receiving signals according to an embodiment; [Figure 7] FIG. 1 is a block diagram illustrating an example of the configuration of an AP according to an embodiment. [Figure 8] FIG. 1 is a block diagram showing an example of the configuration of an STA according to an embodiment. [Figure 9] FIG. 10 is a diagram showing an example of the type of feedback information corresponding to the comparison result with the threshold value. [Figure 10] A flowchart showing an example of a process for selecting a type of feedback information according to an embodiment. [Figure 11] A diagram showing an example of the correspondence between notified cooperation methods and supported cooperation methods. [Figure 12] FIG. 12 is a diagram showing an example of selection of feedback information in the case of the response shown in FIG. 11; [Figure 13] A diagram showing an example of establishing synchronization between APs. [Figure 14] FIG. 10 is a diagram showing an example of changing a threshold value. [Figure 15] Figure 1 shows example 1 of notification of the number of NDPs from an AP to a STA [Figure 16] An example of the Trigger Type subfield value [Figure 17] FIG. 10 is a diagram showing an example of a Trigger Type subfield value according to an embodiment. [Figure 18] Figure 2 shows example 2 of notification of the number of NDPs from an AP to a STA [Figure 19] FIG. 10 is a diagram showing a modification of Example 2 of notifying the number of NDPs from an AP to a STA. [Figure 20] FIG. 10 is a diagram showing an example of the STA info subfield format in Non-Patent Document 4. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings.

[0013] (One embodiment) [Cooperative method] In 11be, for example, the application of DL Multi-AP coordination (hereinafter referred to as "downlink cooperative communication") is being considered, in which access points (also called "base stations", hereinafter referred to as "APs (Access Points)"), which are multiple wireless communication control devices on the signal transmission side, transmit data to terminals (hereinafter referred to as "STAs (Stations)"), which are wireless communication devices on the reception side. In 11be, the use of coordination methods such as Coordinated Spatial Reuse (hereinafter referred to as "CSR"), Coordinated Beamforming (hereinafter referred to as "CBF"), Joint Transmission (hereinafter referred to as "JT"), and Dynamic Point Blanking (hereinafter referred to as "DPB") is being considered for downlink cooperative communication (see, for example, Non-Patent Document 1). Note that DPB may be used in combination with Dynamic Point Selection (see, for example, Non-Patent Document 2).

[0014] Fig. 1 is a diagram showing an example of a cooperation method. Fig. 1 shows an example of the operation of two APs (AP1, AP2) and a STA when using CSR or CBF, DPB, and JT, respectively. In the operation example of Fig. 1, the direction of a downlink signal transmitted and received at a certain time and at a certain frequency is indicated by a solid arrow.

[0015] In the operational example of CSR or CBF in FIG. 1, AP1 transmits a downlink signal (Downlink (DL) signal) to STA1, and AP2 transmits a downlink signal to STA2 at the same time and at the same frequency. Also, in the operational example of DPB in FIG. 1, AP1 transmits a downlink signal to STA1. Note that, although omitted in FIG. 1, in the operational example of DPB, AP2 may transmit a downlink signal to STA2 using a frequency different from the frequency that AP1 uses to transmit a signal to STA1. Also, in the operational example of JT in FIG. 1, both AP1 and AP2 transmit downlink signals to STA1 at the same time and at the same frequency.

[0016] In CSR or CBF, a downlink signal transmitted by AP2 addressed to STA2 becomes an interference wave to STA1 (for example, the dashed arrow in Figure 1), and a downlink signal transmitted by AP1 addressed to STA1 becomes an interference wave to STA2. Note that the interference wave may also be called an interference signal. In the case of CSR, AP1 and AP2 control the transmission power so as to reduce the interference wave. In the case of CBF, AP1 and AP2 perform beamforming to direct a beam to the destination STA (or direct a null to a STA other than the destination) so as to reduce the interference wave.

[0017] In DPB, AP1 and AP2 do not transmit downstream signals at the same frequency, so no interference occurs.

[0018] In JT, AP1 and AP2 transmit downlink signals to STA1, so no interference waves are generated at STA1, and the downlink signals transmitted by AP1 to STA1 and the downlink signals transmitted by AP2 to STA1 increase each other's gain.

[0019] In downlink cooperative communication using the above-mentioned cooperative method, it is considered that the STA receives a signal (for example, a known signal) from the AP and transmits information about the reception quality of the received signal to the AP. Hereinafter, the information about the reception quality transmitted by the STA is referred to as "feedback information."

[0020] In 11be downlink cooperative communications, a method has been proposed in which a STA transmits feedback information from multiple APs by extending the function defined in 11ax, which allows a STA to transmit feedback information to an AP that is the source of a known signal (e.g., Non-Patent Document 3).

[0021] Here, "feedback information of AP" refers to information about the reception quality of a received signal, determined by a STA receiving a signal (e.g., a known signal) from an AP. For example, "feedback information of AP1 and AP2" refers to information about the reception quality of each received signal, determined by a STA receiving a signal from each of AP1 and AP2. "Feedback information of multiple APs" refers to information about the reception quality of each received signal, determined by a STA receiving a signal from each of multiple APs.

[0022] FIG. 2 is a diagram showing an example of a signal transmission and reception sequence. FIG. 2 shows an example in which STA1 and STA2 transmit feedback information of S-AP1, S-AP2, and S-AP3. Note that S-AP1, S-AP2, and S-AP3 are examples of three slave APs (S-APs) that cooperate under the control of a master AP (Master-AP (M-AP)). Also, in FIG. 2, S-AP1 is an AP that has established a wireless connection with STA1, and corresponds to the association AP of STA1. Also, in FIG. 2, S-AP2 corresponds to the association AP of STA2.

[0023] The M-AP transmits a sounding process start trigger for downlink cooperative communication (e.g., a MAP (Multi-AP) Trigger in FIG. 2) to S-AP1, S-AP2, and S-AP3. S-AP1 transmits a packet containing feedback control information (e.g., an AP1 NDPA (null data packet Announcement) in FIG. 2) and a packet containing a known signal (e.g., an AP1 NDP (null data packet) in FIG. 2) to STA1 and STA2. The feedback control information indicates, for example, the type and granularity of information that the STA feeds back to the AP. The known signal is called, for example, a Long Training field (LTF) in 11ax.

[0024] The M-AP sends an NDPA transmission start trigger (e.g., MAP Poll in FIG. 2) to S-AP2. S-AP2 sends an NDPA (AP2 NDPA in FIG. 2) and an NDP (AP2 NDP in FIG. 2) to STA1 and STA2. The M-AP sends a MAP Poll to S-AP3. S-AP3 sends an NDPA (AP3 NDPA in FIG. 2) and an NDP (AP3 NDPA in FIG. 2) to STA1 and STA2. STA1 generates feedback information for each AP based on known signals (e.g., LTF included in the NDP) received from S-AP1, S-AP2, and S-AP3. STA1 sends information including feedback information for each AP (e.g., MAP (Multi-AP) reference feedback in FIG. 2) to the associated AP (e.g., S-AP1 in FIG. 2). STA2 receives a MAP Poll from the associated AP (e.g., S-AP2 in FIG. 2). STA2 transmits MAP reference feedback to S-AP2. Note that in FIG. 2, STA1 transmits MAP reference feedback after receiving AP3 NDPA and AP3 NDP, while STA2 transmits MAP reference feedback after receiving MAP Poll. In other words, the received packet that triggers the transmission of MAP reference feedback differs depending on the STA. For example, the transmission timing of MAP reference feedback (e.g., the received packet that triggers the transmission of MAP reference feedback) may be indicated by the NDPA.

[0025] Next, an example of information that the STA feeds back to the AP, as shown in FIG. 2, will be described.

[0026] 3 is a diagram showing an example of feedback information defined in IEEE 11ax. In FIG. 3, the feedback information shown in Table 9-93b of Non-Patent Document 4 is shown in a table format.

[0027] In Fig. 3, "Average SNR of Space-Time Stream X (X = 1 to Nc)" is information indicating the SNR (Signal to Noise Ratio) (hereinafter referred to as "SNR information"). "Average SNR of Space-Time Stream X (X = 1 to Nc)" represents, for example, a range from -10 dB to 53.75 dB in 0.25 dB steps. "Compressed beamforming feedback matrix V for subcarrier k = scidx(Y) (Y = 0 to Ns-1)" is matrix information for performing beamforming.

[0028] 3, the information to be fed back may be specified in the feedback control information included in the NDPA. Furthermore, "Compressed beamforming feedback matrix V for subcarrier k = scidx(Y) (Y = 0 to Ns-1)" may be quantized by the granularity (for example, the number of bits) specified in the feedback control information included in the NDPA.

[0029] As mentioned above, in 11be downlink cooperative communication, it is considered that a STA transmits feedback information of multiple APs. For example, if the feedback information includes each of the information shown in Figure 3 for one AP, the amount of information in the feedback information of multiple APs may increase.

[0030] Therefore, a non-limiting example of the present disclosure describes a method for appropriately notifying feedback information in downlink cooperative communication by reducing the amount of feedback information.

[0031] [Wireless communication system configuration] A wireless communication system according to an embodiment of the present disclosure includes at least two APs as source devices and one STA. In the following description, for example, a "wireless communication control device" corresponds to an AP, and a "wireless communication device" corresponds to an STA.

[0032] 4 is a block diagram showing an example of the configuration of a portion of the radio communication control device 10. The radio communication control device 10 shown in FIG.

[0033] The control unit 11 generates a signal including a known signal, and the transmission unit 12 transmits a radio signal including the known signal.

[0034] 5 is a block diagram showing an example of the configuration of a portion of the wireless communication device 20. The wireless communication device 20 shown in FIG.

[0035] The receiving unit 21 receives a plurality of radio signals from a plurality of transmission sources (for example, the radio communication control device 10).

[0036] The control unit 22 controls feedback settings for the plurality of radio signals according to differences in reception quality of the plurality of radio signals.

[0037] As an example, the following describes a case where cooperative downlink communication is performed based on feedback information transmission for downlink communication in 11ax.

[0038] Fig. 6 is a diagram showing an example of a signal transmission / reception sequence according to this embodiment. Similar to Fig. 2, Fig. 6 shows an example in which STA1 and STA2 transmit feedback information of S-AP1, S-AP2, and S-AP3. Note that in Fig. 6, explanations of the same parts as in Fig. 2 will be omitted.

[0039] For example, in FIG. 6, the process from MAP Trigger transmission to AP3 NDP transmission is the same as the example shown in FIG. 2, and therefore a description thereof will be omitted.

[0040] STA1 selects a type of feedback information based on known signals included in the NDPs received from S-AP1, S-AP2, and S-AP3. STA1 generates feedback information for S-AP1, S-AP2, and S-AP3 having the selected type, and transmits information including the feedback information for S-AP1, S-AP2, and S-AP3 (e.g., MAP (Multi-AP) selected reference feedback in FIG. 6) to the associated AP (e.g., S-AP1 in FIG. 6). An example of selecting a type of feedback information will be described later.

[0041] S-AP2 (e.g., the associated AP of STA2 in FIG. 6) transmits a MAP Poll to STA2. STA2, like STA1, selects the types of feedback information for S-AP1, S-AP2, and S-AP3 based on the known signals received from S-AP1, S-AP2, and S-AP3. STA2 generates feedback information for S-AP1, S-AP2, and S-AP3 having the selected types, and transmits information including the feedback information for S-AP1, S-AP2, and S-AP3 (e.g., MAP selected reference feedback in FIG. 6) to the associated AP (e.g., S-AP2 in FIG. 6).

[0042] 6, the MAP Poll transmitted from S-AP2 to STA2 may be a BFRP (Beamforming Report Poll) trigger in 11ax. Also, after the AP3 NDP transmitted from S-AP3 to STA1, a MAP Poll or BFRP trigger may be transmitted from S-AP1 to STA1 (see, for example, Section 26.7.3 of Non-Patent Document 4).

[0043] [Configuration of wireless communication control device] 7 is a block diagram showing an example of the configuration of a radio communication control apparatus 100 according to this embodiment. In FIG. 7, the radio communication control apparatus 100 has a known signal generating unit 101, a transmission packet generating unit 102, a radio transmitting / receiving unit 103, and a received packet decoding unit 104.

[0044] The radio communication control device 100 shown in Fig. 7 corresponds to an example of the radio communication control device 10 shown in Fig. 4. The radio transmitting / receiving unit 103 in Fig. 7 corresponds to an example of the transmitting unit 12 in Fig. 4, and the known signal generating unit 101 and the transmission packet generating unit 102 in Fig. 7 may correspond to an example of the control unit 11 in Fig. 4.

[0045] The known signal generating unit 101 generates a known signal. In 11ax, the known signal may be called, for example, a long training field (LTF).

[0046] The transmission packet generator 102 generates a transmission packet based on the transmission data and the known signal generated by the known signal generator 101. The generated transmission packet includes, for example, at least one of MAP Trigger, NDPA, NDP, and MAP Poll shown in FIG.

[0047] The radio transmission / reception unit 103 performs predetermined radio transmission processing on the transmission packet to convert it into a radio transmission signal, which is then transmitted from an antenna.

[0048] The radio transmission / reception unit 103 receives a radio reception signal from an antenna. The radio transmission / reception unit 103 performs predetermined radio reception processing on the received radio transmission / reception signal to generate a reception packet. The reception packet may include, for example, at least one of MAP Trigger, MAP Poll, and MAP selected reference feedback shown in FIG. 6.

[0049] The received packet decoder 104 decodes the received packet to generate received data.

[0050] [Configuration of wireless communication device] Fig. 8 is a block diagram showing an example configuration of wireless communication apparatus 200 according to this embodiment. In Fig. 8, wireless communication apparatus 200 has wireless transmission / reception section 201, received packet decoding section 202, reception quality measurement section 203, feedback information selection section 204, feedback information generation section 205, and transmission packet generation section 206.

[0051] Wireless communication device 200 shown in Fig. 8 corresponds to an example of wireless communication device 20 shown in Fig. 5. Moreover, wireless transmission / reception unit 201 in Fig. 8 corresponds to an example of reception unit 21 in Fig. 5, and reception quality measurement unit 203 and feedback information selection unit 204 in Fig. 8 may correspond to an example of control unit 22 in Fig. 5.

[0052] The wireless transmission / reception unit 201 receives a wireless reception signal from an antenna. The wireless transmission / reception unit 201 performs predetermined wireless reception processing on the received wireless transmission / reception signal to generate a reception packet. The reception packet may include, for example, at least one of NDPA, NDP, and MAP Poll.

[0053] The received packet decoder 202 decodes the received packet to generate received data.

[0054] When an NDP is included in a received packet, reception quality measurement section 203 measures reception quality from a known signal included in the NDP. Reception quality measurement section 203 notifies feedback information selection section 204 and feedback information generation section 205 of the measured reception quality. Note that the notified reception quality may be associated with the AP that is the source of the NDP that is the target of the reception quality.

[0055] Feedback information selection section 204 and feedback information generation section 205 store the notified reception quality. When multiple notifications are received from reception quality measurement section 203, feedback information selection section 204 and feedback information generation section 205 store the multiple notified reception qualities.

[0056] The feedback information selection unit 204 controls the feedback setting based on the reception quality acquired from the reception quality measurement unit 203. The control of the feedback setting includes, for example, selecting the type of feedback information. The control of the feedback setting may also include selecting whether or not to transmit the feedback information. The control of the feedback setting may also include controlling the setting of the destination of the feedback information and / or the setting of the configuration of the feedback information.

[0057] For example, when feedback information selection section 204 receives a triggering reception packet (for example, when STA1 receives AP3 NDP and STA2 receives MAP Poll in the example of FIG. 6), feedback information selection section 204 selects a type of feedback information based on reception quality. Then, feedback information selection section 204 notifies feedback information generation section 205 of the selected type. Feedback information selection section 204 may also notify feedback information generation section 205 of setting information related to the destination of the feedback information and the configuration of the feedback information.

[0058] Here, the type selected by the feedback information selection unit 204 may be different from the type specified by the feedback control information included in the NDPA.

[0059] 6, when STA1 receives an AP3 NDP and when STA2 receives a MAP Poll, feedback information generation section 205 generates feedback information for S-AP1, S-AP2, and S-AP3 based on the type notified by feedback information selection section 204. Note that feedback information generation section 205 may set the transmission destination and / or configuration of the feedback information based on the setting information notified by feedback information selection section 204.

[0060] The transmission packet generator 206 generates a transmission packet including feedback information of S-AP1, S-AP2, and S-AP3 generated in the feedback information generator 205 (for example, MAP selected reference feedback in FIG. 6).

[0061] The radio transmission / reception unit 201 performs predetermined radio transmission processing on the transmission packet to convert it into a radio transmission signal, which is then transmitted from an antenna.

[0062] [Example of selecting the type of feedback information] In cooperative communication, where multiple APs cooperate to communicate with a STA, the effective cooperative method varies depending on the difference in reception quality of the signal received by the STA from each of the multiple APs. Here, the reception quality of the received signal may be, for example, the reception level (e.g., received power) or other information related to reception quality.

[0063] An example of the relationship between the reception level difference and the cooperative method will be described below using the example of Fig. 1. In the example of Fig. 1, the reception level difference at STA1 corresponds to the difference between the reception level of the signal that STA1 receives from AP1 (hereinafter referred to as "AP1 reception level") and the reception level of the signal that STA1 receives from AP2 (hereinafter referred to as "AP2 reception level"). An example will be described below in which the reception level difference is the value obtained by subtracting the AP2 reception level from the AP1 reception level.

[0064] In Fig. 1, in CSR or CBF, a downlink signal from AP2 to STA2 becomes an interference wave to STA1, so CSR or CBF is effective when the reception level of AP2 at STA1 is sufficiently smaller than the reception level of AP1 (for example, when the reception level difference is greater than a certain threshold). Furthermore, of CSR and CBF, CBF is more effective at reducing interference waves than CSR because each AP performs beamforming. In other words, CSR is less effective at reducing interference waves than CBF, so it is desirable for the reception level difference to be greater than in the case of CBF.

[0065] Furthermore, in JT, AP1 and AP2 transmit downlink signals to STA1, so when the difference in reception level at STA1 is relatively small, it is more effective than when the difference in reception level is relatively large.

[0066] As described above, the effective cooperation method varies depending on the difference in reception level. For example, in terms of the relationship between the difference in reception level and the cooperation method, the effective cooperation methods may be CSR, CBF, DPB, and JT in descending order of the difference in reception level.

[0067] Furthermore, since the information used in each cooperative scheme is different, the appropriate feedback information differs for each cooperative scheme.

[0068] For example, in the case of CSR, the reception level of an interference wave is used for transmission power control and MCS (Modulation and Coding Scheme) selection in transmitting a downlink signal. Therefore, feedback information from an AP that transmits an interference signal includes information about the reception level. Here, the AP that transmits an interference signal corresponds to AP2 in STA1 in the example of FIG. 1, for example. Furthermore, the information about the reception level corresponds to SNR information in FIG. 3, for example.

[0069] In the case of CBF, an AP (e.g., AP2 in FIG. 1) that transmits an interfering signal performs beamforming (forming a directional beam) to direct a null toward a STA (e.g., STA1 in FIG. 1) that may cause interference. Therefore, the feedback information of the AP that transmits the interfering signal includes information that the AP uses to perform beamforming. The information that the AP uses to perform beamforming corresponds to, for example, the SNR information and matrix information in FIG. 3. Hereinafter, the information that the AP uses to perform beamforming may be referred to as information about beamforming.

[0070] In the case of DPB and JT, feedback information from APs other than the source AP is not required. However, in the case of DPB, there is only one source AP, while in the case of JT, there are multiple source APs. Therefore, in the case of JT, feedback information from multiple APs is desired.

[0071] As described above, the effective cooperative method differs depending on the difference in reception level, and the feedback information desired in the cooperative method differs, so appropriate (or effective) feedback information may differ depending on the difference in reception level. Below, an example of the correspondence between the difference in reception level and the type of feedback information will be described.

[0072] For example, in the example of Figure 6, an example of the operation of the feedback information selection unit 204 is shown when the relationship between the reception levels of each S-AP at STA1 is "reception level of S-AP1" > "reception level of S-AP2" > "reception level of S-AP3".

[0073] The feedback information selection unit 204 sets S-AP1, which has the highest reception level, as the reference transmission source from the reception levels of the stored S-AP1, S-AP2, and S-AP3. The feedback information selection unit 204 calculates the reception level difference ΔP2 between S-AP1 and S-AP2 and the reception level difference ΔP3 between S-AP1 and S-AP3 by using ΔPn (n=2, 3) = "reception level of S-AP1" - "reception level of S-APn".

[0074] The feedback information selection unit 204 controls the feedback setting by comparing the thresholds Xcsr, Xcbf, and Xjt with ΔPn. For example, the feedback information selection unit 204 selects the feedback information type of S-AP2 and the feedback information type of S-AP3.

[0075] Fig. 9 is a diagram showing an example of the type of feedback information corresponding to the comparison result with the threshold. Fig. 9 shows the type of feedback information of APn corresponding to the comparison result with the threshold, and the reception level difference ΔPn between the reference transmission source (S-AP1 in the above example) and APn (n=2, 3 in the above example). For example, feedback information selection section 204 selects the type of feedback information of APn based on the example of Fig. 9.

[0076] Xcsr is determined based on the difference in reception levels at which CSR is effective. For example, if the difference in reception levels ΔP2 between S-AP1 and S-AP2 is greater than Xcsr, CSR is effective in the cooperation scheme used by S-AP1 and S-AP2.

[0077] Xcbf is determined based on the difference in reception levels at which CBF is effective. For example, if the reception level difference ΔP2 between S-AP1 and S-AP2 is greater than Xcbf, CBF is effective in the cooperation scheme used by S-AP1 and S-AP2.

[0078] Xjt is determined based on the difference in reception levels at which JT is effective. For example, if the reception level difference ΔP2 between S-AP1 and S-AP2 is equal to or less than Xjt, JT is effective in the cooperation scheme used by S-AP1 and S-AP2.

[0079] As mentioned above, CSR or CBF is more effective when the difference in reception levels is relatively large, and therefore is effective when the difference in reception levels is larger than the threshold (Xcsr or Xcbf). On the other hand, JT is more effective when the difference in reception levels is relatively small, and therefore is effective when the difference in reception levels is smaller than the threshold (Xjt). Furthermore, since it is desirable for CSR to have a larger difference in reception levels than CBF, Xcsr may be larger than Xcbf. Due to the difference in the difference in reception levels at which the cooperative method is effective, the three thresholds may have the relationship Xcsr > Xcbf > Xjt.

[0080] In the example of FIG. 9, if "ΔPn>Xcsr" holds, the type of feedback information of APn is selected to be reception level. The reception level is an example of feedback information corresponding to CSR. Furthermore, if "Xcsr≧ΔPn>Xcbf" holds, the type of feedback information of APn is selected to be information related to beamforming. Information related to beamforming is an example of feedback information corresponding to CBF. Furthermore, if "Xcbf≧ΔPn>Xjt" holds, the feedback information of APn is selected to be unnecessary. This selection of unnecessary feedback information can be considered as an example of feedback information corresponding to DPB. Furthermore, if "Xjt≧ΔPn" holds, the feedback information of APn is selected to be of a type specified in NDPA. Feedback information of a type specified in NDPA is an example of feedback information corresponding to JT.

[0081] If there are multiple APs that are different from the reference source, the reception level difference may be determined for each AP, and the reception level difference may be compared with a threshold value, and the type of feedback information for each AP may be selected.

[0082] Furthermore, the "reception level" shown in Fig. 9 may be the SNR information shown in Fig. 3. Furthermore, the information relating to beamforming shown in Fig. 9 may be the SNR information and matrix information shown in Fig. 3.

[0083] The feedback information of the reference source (S-AP1 in the above example) may be of a type specified by the NDPA shown in FIG.

[0084] Furthermore, in "ΔPn>Xcsr" and "Xcsr≧ΔPn>Xcbf", the greater the difference in reception levels (the smaller the reception level that causes interference), the less the impact of interference waves on reception processing. Therefore, when the difference in reception levels is large, the amount of feedback information may be reduced.

[0085] The method for reducing the amount of information is not particularly limited. For example, when the feedback information includes SNR information, the amount of information may be reduced by increasing the step of the SNR information shown in Fig. 3. Also, when the feedback information includes matrix information, the amount of information may be reduced by reducing the number of quantization bits of the matrix information.

[0086] Furthermore, when the feedback setting supports CSR (for example, when "ΔPn>Xcsr"), the feedback information may be information on the reception level of each block (for example, multiple subcarriers) obtained by dividing the frequency domain into multiple blocks. This allows the AP to determine the subcarriers for which CSR is more effective. Furthermore, even when the reception level of a subcarrier fluctuates significantly, appropriate MCS selection and transmission power control are possible, improving throughput.

[0087] By selecting feedback information adapted to the situation through the above-described selection, the amount of feedback information can be reduced, and the system improvement effect of downlink cooperative communication is improved.

[0088] In the above example, the AP with the highest reception level is set as the reference transmission source, but the association AP may also be set as the reference transmission source. This allows the transmission source AP in CSR, CBF, and DPB data communications to be the association AP. Also, the AP with the highest reception level may be the reference transmission source and the association AP.

[0089] The reference transmission source may also be designated by the AP. For example, the AP may designate the STA to set the reference transmission source to the AP with the highest reception level, or to set the reference transmission source to the associated AP, by notification to the STA. The notification designating the reference transmission source may be included in the broadcast information (beacon) transmitted by the AP at regular intervals, or may be included in the NDPA or MAP Poll shown in FIG. 6.

[0090] Next, an example of a process for selecting the type of feedback information in this embodiment will be described.

[0091] Fig. 10 is a flowchart showing an example of a process for selecting a type of feedback information in this embodiment. The flow shown in Fig. 10 is executed, for example, after a STA receives known signals from multiple APs. For example, the flow shown in Fig. 10 is executed after STA1 and STA2 receive an AP3 NDP in Fig. 6.

[0092] The STA detects the maximum reception level from among the reception levels of the received known signals (S101).

[0093] The STA determines whether or not the process of selecting the type of feedback information has been completed for all reception levels of the received known signals (S102).

[0094] If the process is complete (Yes in S102), in other words, if there are no unprocessed reception levels, the STA ends the process of selecting the type of feedback information.

[0095] If the processing is not completed (No in S102), in other words, if there are unprocessed reception levels, the STA sets one of the unprocessed reception levels as the reception level to be processed (S103). Each reception level may be associated with the source of the known signal corresponding to that reception level. Hereinafter, the source of the known signal corresponding to the reception level may be abbreviated as the "source of the reception level."

[0096] The STA determines whether the reception level to be processed is the maximum value (S104), where the maximum value is the value detected in S101.

[0097] If the reception level to be processed is the maximum value (Yes in S104), the STA selects that the type of feedback information is "the type specified by NDPA" (S105). Then, the flow proceeds to S102.

[0098] If the reception level to be processed is not the maximum value (No in S104), the STA sets the value obtained by dividing the reception level to be processed from the maximum reception level as the reception level difference ΔPn (S106), where n may be an index assigned to the sender of the reception level to be processed.

[0099] The STA determines whether or not "ΔPn>Xcsr" is true (S107).

[0100] If "ΔPn>Xcsr" is true (Yes in S107), the STA selects that the type of feedback information is "reception level" (S108), and the flow then returns to S102.

[0101] If "ΔPn>Xcsr" is not true (No in S107), the STA determines whether "ΔPn>Xcbf" is true (S109).

[0102] If "ΔPn>Xcbf" is true (Yes in S109), the STA selects that the type of feedback information is "information related to beamforming" (S110), and the flow then returns to S102.

[0103] If "ΔPn>Xcbf" is not true (No in S109), the STA determines whether "ΔPn>Xjt" is true (S111).

[0104] If "ΔPn>Xjt" is true (Yes in S111), the STA selects no feedback information (S112), and the flow returns to S102.

[0105] If "ΔPn>Xjt" does not hold (No in S111), that is, if "Xjt≧ΔPn" holds, the STA selects that the type of feedback information is "the type specified by the NDPA" (S113). Then, the flow returns to S102.

[0106] According to the flow described above, the STA selects the type of feedback information for each AP and generates feedback information of the selected type.

[0107] As described above, the type of feedback information may be selected based on the comparison result between a predetermined threshold and the difference in reception quality (for example, the difference in reception level). This allows appropriate feedback information adapted to the situation, such as the communication environment, to be notified. This also allows the amount of feedback information to be reduced, thereby increasing the system improvement effect of downlink cooperative communication.

[0108] [Feedback information type selection variation 1] In the above example, valid feedback information is selected from four cooperation schemes (CSR, CBF, DPB, and JT), but the present disclosure is not limited to this. The number of cooperation schemes that can be selected may be five or more, or three or less. For example, a cooperation scheme other than CSR, CBF, DPB, and JT may be included in the cooperation schemes that can be selected, or any of CSR, CBF, DPB, and JT may be excluded from the cooperation schemes that can be selected.

[0109] For example, some APs may not support all of the four cooperation methods described above. In this case, the AP may notify the STAs of the cooperation methods that it supports, allowing the STAs to select valid feedback information.

[0110] For example, the AP may notify information indicating at least one cooperation scheme among the cooperation schemes it supports (e.g., supported cooperation schemes or operable cooperation schemes). In this case, the STA may determine the cooperation scheme supported by the AP based on the notified cooperation scheme. Alternatively, in this case, the STA may change the selection process for the type of feedback information based on the notified cooperation scheme.

[0111] FIG. 11 is a diagram illustrating an example of the correspondence between notified cooperation methods and supported cooperation methods.

[0112] For example, in the example of Fig. 11, if the notified cooperation method is JT, the notifying AP can operate CSR, CBF, DPB, and JT. Also, in the example of Fig. 11, if the notified cooperation method is CBF, the notifying AP can operate CSR, CBF, and DPB. Also, in the example of Fig. 11, if the notified cooperation method is CSR, the notifying AP can operate CSR and DPB.

[0113] In addition, the cooperative DPB method does not require feedback information other than that of the reference source, so it may be operable with all notifications.

[0114] FIG. 12 is a diagram showing an example of selection of feedback information in the case of the handling shown in FIG.

[0115] If the notified cooperation method is CSR, since the AP does not support CBF and JT, the STA does not compare Xcbf with ΔPn or Xjt with ΔPn, but instead compares Xcsr with ΔPn to determine the type of feedback information.

[0116] If the notified cooperation method is CBF, the AP does not support JT, so the STA does not compare Xjt with ΔPn, but instead compares Xcbf with ΔPn and Xcsr with ΔPn to determine the type of feedback information.

[0117] If the notified cooperation method is DPB, since the AP does not support CSR, CBR, and JT, the STA does not compare Xcbf with ΔPn, Xjt with ΔPn, and Xcsr with ΔPn, and determines that feedback information is not necessary.

[0118] When the notified cooperation method is JT, the AP corresponds to four cooperation methods, and therefore, similarly to FIG. 9, compares the three thresholds with ΔPn and determines the type of feedback information.

[0119] By notifying the AP of the cooperation method, it is possible to select an appropriate type of feedback information based on the reception quality (for example, reception level) and the cooperation method supported by the AP.

[0120] In JT, a STA simultaneously receives transmission signals from multiple APs, which are the source of the signals, and therefore synchronization is achieved between the cooperating APs.

[0121] FIG. 13 is a diagram illustrating an example of establishing synchronization between APs.

[0122] 13, signals transmitted and received between AP1 and STA1 that can communicate with AP2 are used to synchronize AP1 and AP2. In this synchronization method, if there are no STAs that can communicate with multiple APs to synchronize with, synchronization will not be achieved.

[0123] For example, if JT is supported but synchronization between APs is not possible, the AP may notify CBF as the coordination method. This allows for a comparison of whether "Xjt > ΔPn" holds when synchronization is not possible, and for the AP to not select the corresponding type if "Xjt > ΔPn" holds. This allows for the selection of feedback information that is more appropriate for the situation.

[0124] The notification information of the cooperation method from the AP may be included in the broadcast information (beacon) transmitted by the AP at regular intervals or in the NDPA or MAP Poll shown in FIG.

[0125] Alternatively, instead of the AP notifying the STA of the cooperation method, the STA may change at least some of the values ​​of the thresholds Xcsr, Xcbf, and Xjt. For example, information indicating the changed thresholds may be notified to the STA from the AP.

[0126] Fig. 14 is a diagram showing an example of changing the threshold value, which corresponds to the notification cooperation method shown in Fig. 12 and defines an operation equivalent to the notification.

[0127] For example, thresholds that support the same operation as when the notified cooperation method is CSR may be set by changing Xcbf to the maximum value and Xjt to the minimum value. Note that the maximum value here may be the maximum value among the possible values ​​of ΔPn, or a value sufficiently larger than the possible values ​​of ΔPn. Furthermore, the minimum value may be the minimum value among the possible values ​​of ΔPn, or a value sufficiently smaller than the possible values ​​of ΔPn.

[0128] In this case, for example, because Xcbf is changed to its maximum value, the condition "Xcsr ≥ ΔPn > Xcbf" in Figure 9 does not hold, regardless of the value of ΔPn. Also, for example, because Xjt is changed to its minimum value, the condition "Xjt > ΔPn" in Figure 9 does not hold, regardless of the value of ΔPn. The fact that these conditions do not hold means that the "information about beamforming" and "type specified in NDPA" shown in Figure 9 are not selected, and therefore the same behavior as when the coordination method to be notified is CSR is specified.

[0129] For example, when downlink cooperative communication is performed using CSR and CBF, system throughput improves while user throughput of the STAs involved in the coordination decreases. Also, when downlink cooperative communication is performed using JT, user throughput of the STA that receives the downlink signal improves while system throughput decreases. Therefore, to improve system throughput, the three threshold values ​​may be adjusted to make CSR and CBF more likely to be applied to the coordination method. For example, by adjusting Xcsr, Xcbf, and Xjt to smaller values, the likelihood of the conditions "ΔPn > Xcsr" and "Xcsr ≧ ΔPn > Xcbf" being met increases, while the likelihood of the condition "Xjt ≧ ΔPn" being met decreases.

[0130] Furthermore, for example, if it is desired to increase user throughput, the values ​​of the three thresholds may be adjusted to make it easier for JT to be applied to the cooperative method. For example, by adjusting Xcsr, Xcbf, and Xjt to larger values, the likelihood that the conditions "ΔPn > Xcsr" and "Xcsr ≥ ΔPn > Xcbf" hold decreases, and the likelihood that the condition "Xjt ≥ ΔPn" holds increases.

[0131] The threshold may be adjusted by the AP, and the adjusted threshold may be notified to the STA from the AP, thereby enabling selection of an appropriate type of feedback information.

[0132] Xcsr, Xcbf, and Xjt may be included in the notification information (beacon) transmitted by the AP at regular intervals or in the NDPA or MAP Poll shown in FIG.

[0133] In the above-described variation 1, an example was shown in which candidates for selecting feedback information are limited by information notified by an AP. For example, the information notified by an AP may be information about a cooperation method supported by the AP. In this case, the information to be notified may be changed depending on the synchronization status of multiple cooperating APs.

[0134] [Example of notification regarding feedback type selection] For example, when each of multiple APs transmits an NDP to a STA, the AP may notify the STA of information confirming completion of NDP transmission (information used by the STA to determine completion of NDP reception). For example, the information confirming completion of NDP transmission may be information indicating the number of NDPs to be transmitted (or, in the case of a STA, the number of NDPs to be received), or may be information indicating whether NDP transmission continues. For example, the STA may determine whether reception of the NDP is complete based on the information confirming completion of NDP transmission. Then, when reception of the NDP is complete, the STA may transmit the MAP selected reference feedback shown in FIG. 6. An example of notification of information confirming completion of NDP transmission from an AP to a STA is shown below.

[0135] <Notification example 1> In notification example 1, the AP notifies the number of NDPs in a newly defined trigger frame.

[0136] Fig. 15 is a diagram showing example 1 of notification of the number of NDPs from an AP to a STA. Fig. 15 shows an example in which STA1 and STA2 transmit feedback information of S-AP1, S-AP2, and S-AP3, similar to Fig. 2 and Fig. 6. Note that in Fig. 15, descriptions of the same parts as Fig. 2 and Fig. 6 will be omitted.

[0137] In Fig. 15, the MAP Poll transmitted from S-AP2 to STA2 shown in Fig. 6 is replaced with a New Poll. The New Poll is an example of a newly defined trigger frame. The New Poll includes information indicating the number of NDPs.

[0138] The configuration of the trigger frame is not particularly limited, but may be newly defined in addition to the definitions described in Non-Patent Document 4, for example.

[0139] Fig. 16 is a diagram showing an example of a Trigger Type subfield value. Fig. 16 shows the relationship between the type of trigger frame and the subfield value corresponding to that type, as described in Non-Patent Document 4 (see Table 9-31b in Non-Patent Document 4).

[0140] For example, in Non-Patent Document 4, the MAP Poll is defined as a BFRP (Beamforming Report Poll), and the trigger frame number is defined by the Trigger Type subfield value, which has values ​​from 0 to 15 (for example, values ​​expressed in 4 bits) shown in FIG.

[0141] For example, the newly defined trigger frame shown in FIG. 15 may be defined using the unused area (Reserved) in FIG.

[0142] FIG. 17 is a diagram showing an example of a Trigger Type subfield value in this embodiment.

[0143] As shown in Figure 17, one of the unused areas of the trigger frame number ("8-15" in the example of Figure 16) ("8" in the example of Figure 17) may be used as the trigger frame number of a newly defined trigger frame (Beamforming Report Poll with the number of NDPs added in the figure).

[0144] After the AP3 NDP transmitted from S-AP3 to STA1 shown in FIG. 15, a newly defined trigger frame may be transmitted from S-AP1 to STA1.

[0145] Furthermore, the information added to the newly defined trigger frame may be the IDs of multiple APs that transmit the NDP.

[0146] <Notification example 2> In Notification Example 2, the AP notifies the number of NDPs in a newly defined NDPA.

[0147] Fig. 18 is a diagram showing example 2 of notification of the number of NDPs from an AP to a STA. Fig. 18 shows an example in which STA1 and STA2 transmit feedback information of S-AP1, S-AP2, and S-AP3, similar to Fig. 2 and Fig. 6. Note that in Fig. 18, descriptions of the same parts as Fig. 2 and Fig. 6 will be omitted.

[0148] In Fig. 6, S-AP1, S-AP2, and S-AP3 transmit NDPA and NDP, respectively. In Fig. 18, a "new NDPA" is defined, and an AP may notify the number of NDPs or the ID of the AP that transmits the NDP by the new NDPA.

[0149] Although FIG. 18 shows an example in which S-AP1 transmits a new NDPA, multiple S-APs or M-APs may transmit new NDPAs.

[0150] Fig. 19 is a diagram showing a modified example of Example 2 of notification of the number of NDPs from an AP to a STA. Fig. 19 shows an example in which STA1 and STA2 transmit feedback information of S-AP1, S-AP2, and S-AP3, similar to Figs. 2 and 6. Note that in Fig. 19, descriptions of the same parts as Figs. 2 and 6 will be omitted.

[0151] When the M-AP transmits a new NDPA, it is not necessary to transmit a MAP Trigger and the new NDPA transmitted by the S-AP1, as shown in Fig. 19. Furthermore, the M-AP may transmit a MAP Poll to the S-AP1 after transmitting the new NDPA.

[0152] <Notification example 3> In Notification Example 1 and Notification Example 2, the number of NDPs is notified as an example of information for confirming the completion of NDP transmission. In Notification Example 3, instead of notifying the number of NDPs, an NDPA is used to notify whether or not an NDP following the NDPA (hereinafter, a subsequent NDP) exists. For example, an unused value in the NDPA is used to notify whether or not a subsequent NDP exists.

[0153] Figure 20 is a diagram showing an example of the STA info subfield format of Non-Patent Document 4. For example, for unused values, any of 74 to 127 of the "RU Start index" or "RU End index" indicated in "Partial BW info" in the "STA info subfield" in Figure 20, which is the 11ax NDPA format, may be used (see Figure 9-61b and Figure 9-61c of Non-Patent Document 4).

[0154] For example, in S-AP1, S-AP2, and S-AP3 of FIG. 6, an example of operation is shown in which, when there is a subsequent NDP, the RU Start index of one unused value is set to 127. At the stage when S-AP1 transmits an NDPA, there are subsequent NDPs (in the example of FIG. 6, the NDPs of S-AP2 and S-AP3), so AP1 transmits an NDPA with the RU Start index changed to 127. At the stage when S-AP2 transmits an NDPA, there is a subsequent NDP (in the example of FIG. 6, the NDP of S-AP3), so S-AP2 transmits an NDPA with the RU Start index changed to 127, just like S-AP1. At the stage when S-AP3 transmits an NDPA, there are no subsequent NDPs, so S-AP3 transmits an NDPA with the RU Start index changed to one of values ​​0 to 126 (for example, 0).

[0155] STA1 and STA2 determine that there are subsequent NDPs (e.g., NDPA and NDP) because the RU Start index of the AP1 NDPA and AP2 NDPA is 127. STA1 and STA2 also determine that there are no subsequent NDPs (NDPA and NDP) because the RU Start index of the AP3 NDPA is 0. STA1 and STA2 select feedback information when they determine that there are no subsequent NDPs (NDPA and NDP). STA1 and STA2 may replace the value of 127 of the RU Start index of the received AP1 NDPA and AP2 NDPA with the value (e.g., 0) notified in the AP3 NDPA.

[0156] As described above, the AP notifies the STA of the information confirming the completion of NDP transmission, so that the STA can determine the completion of NDP reception and start controlling the feedback setting. This reduces the processing load (e.g., processing time) related to feedback control.

[0157] The feedback information may include information that identifies the source of the known signal.

[0158] For example, the feedback information shown in FIG. 6 (MAP selected reference feedback in the figure) includes feedback information for S-AP1, S-AP2, and S-AP3. On the other hand, for example, in FIG. 6, if the condition "Xcbf≧ΔPn>Xjt" is met, feedback information is unnecessary. In this case, the number of known signal transmission sources may not match the amount of information about the reception quality of the known signals to be fed back. In such a case, by including information identifying the known signal transmission sources in the feedback information, the AP that receives the feedback information can associate information about the reception quality of the known signals with the transmission sources of the known signals.

[0159] For example, as shown in FIG. 6, when a known signal is transmitted for each AP, the information identifying the source of the known signal may be the ID of the AP. When the known signal for each AP is transmitted by frequency multiplexing, the information identifying the source of the known signal may be the frequency number of the frequency on which the known signal is multiplexed. When the known signal is transmitted by spatial multiplexing, the information identifying the source of the known signal may be the stream number on which the known signal is multiplexed. When the known signal for each AP is transmitted by code multiplexing, the information identifying the source of the known signal may be a code number.

[0160] The feedback information of each of the multiple APs may be transmitted individually.

[0161] The feedback information shown in FIG. 6 (MAP selected reference feedback in the figure) includes feedback information for S-AP1, feedback information for S-AP2, and feedback information for S-AP3, but the feedback information for S-AP1, feedback information for S-AP2, and feedback information for S-AP3 may each be transmitted in the MAP selected reference feedback.

[0162] The feedback information may be sent to multiple sources.

[0163] In the example shown in Figure 6, the STAs transmit feedback information to the associated APs. For example, STA1 in Figure 6 transmits feedback information to S-AP1, and STA2 transmits feedback information to S-AP2. The present disclosure is not limited to this example.

[0164] For example, the STA may transmit feedback information to multiple sources of known signals. The STA may also transmit feedback information to multiple APs (S-AP1, S-AP2, and S-AP3 in the example of FIG. 4). This allows feedback information to be obtained by multiple APs, eliminating the need to transfer feedback information between APs.

[0165] Also, for example, the STA may send feedback information to the master AP. This allows the master AP to manage the feedback information and reduce the amount of information transferred between APs. Note that if a STA has difficulty sending to the master AP, it may change the destination of the feedback information to the associated AP.

[0166] In the above-described embodiment, an example has been shown in which multiple APs perform cooperative communication with a STA, but the present disclosure is not limited to this. For example, some of the multiple APs may be replaced with STAs. For example, the present disclosure may be applied to a case in which one or more APs and one or more STAs perform cooperative communication with another STA. Alternatively, the present disclosure may be applied to a case in which two or more STAs perform cooperative communication with another STA.

[0167] Furthermore, the terms used to represent each signal (each packet) in the above-described embodiment are merely examples, and the present disclosure is not limited to these.

[0168] Furthermore, the notation "··· part" in the above-described embodiments may be replaced with other notations such as "··· circuitry," "··· device," "··· unit," or "··· module."

[0169] The present disclosure can be realized by software, hardware, or software in conjunction with hardware. Each functional block described in the above embodiments may be partially or entirely realized as an LSI, which is an integrated circuit. Each process described in the above embodiments may be partially or entirely controlled by a single LSI or a combination of LSIs. An LSI may be composed of individual chips, or may be composed of a single chip that includes some or all of the functional blocks. An LSI may have data inputs and outputs. Depending on the level of integration, an LSI may be referred to as an IC, system LSI, super LSI, or ultra LSI. The integration method is not limited to LSIs; it may also be realized by dedicated circuits, general-purpose processors, or dedicated processors. Furthermore, a field programmable gate array (FPGA), which can be programmed after LSI fabrication, or a reconfigurable processor, which allows the connections and settings of circuit cells within an LSI to be reconfigured, may also be used. The present disclosure may be realized as digital or analog processing. Furthermore, if an integrated circuit technology that can replace LSI emerges due to advances in semiconductor technology or other derivative technologies, it is natural that such technology can be used to integrate functional blocks. The application of biotechnology is also a possibility.

[0170] The present disclosure may be implemented in any type of apparatus, device, or system with communications capabilities (collectively referred to as communications apparatus), including, but not limited to, telephones (e.g., cell phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks), cameras (e.g., digital still / video cameras), digital players (e.g., digital audio / video players), wearable devices (e.g., wearable cameras, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine devices, communications-enabled vehicles or mobile transportation (e.g., cars, airplanes, ships), and combinations of the above.

[0171] Communications equipment is not limited to portable or mobile equipment, but also includes non-portable or fixed equipment, devices, and systems of any kind, such as smart home devices (such as appliances, lighting equipment, smart meters or metering devices, control panels, etc.), vending machines, and any other "things" that may exist on an IoT (Internet of Things) network.

[0172] Communications include data communications via cellular systems, wireless LAN systems, communications satellite systems, etc., as well as data communications via combinations of these.

[0173] A communications apparatus also includes devices such as controllers and sensors connected or coupled to a communications device that performs the communications functions described in this disclosure, such as controllers and sensors that generate control and data signals used by the communications device to perform the communications functions of the communications apparatus.

[0174] The communication apparatus also includes infrastructure facilities, such as base stations, access points, and any other apparatus, device, or system that communicates with or controls the various apparatuses listed above, but are not limited to these.

[0175] A wireless communication device according to one embodiment of the present disclosure includes a receiving circuit that receives multiple wireless signals transmitted from multiple sources, and a control circuit that controls feedback settings for the multiple wireless signals in accordance with differences in reception quality of the multiple wireless signals.

[0176] In one embodiment of the present disclosure, the control circuit controls the setting based on a comparison result between a difference in reception quality between a first transmission source selected from the plurality of transmission sources and another second transmission source and a threshold value.

[0177] In one embodiment of the present disclosure, the first transmission source is a transmission source of the wireless signal that exhibits the best reception quality among the plurality of transmission sources.

[0178] In one embodiment of the present disclosure, the first source is a source that has established an association with the wireless communication device.

[0179] In one embodiment of the present disclosure, the feedback settings include any two or more of settings corresponding to Coordinated Spatial Reuse (CSR), Coordinated Beamforming (CBF), Joint Transmission (JT), and Dynamic Point Blanking (DPB).

[0180] In one embodiment of the present disclosure, when the feedback setting corresponds to Coordinated Spatial Reuse (CSR), the control circuit includes in the feedback information regarding the reception quality in each of multiple blocks divided into a frequency domain.

[0181] In one embodiment of the present disclosure, the receiving circuit receives control information indicating the cooperative communication method supported by the multiple transmission sources, and the control circuit determines the feedback setting based on the information regarding the reception quality and the control information.

[0182] In one embodiment of the present disclosure, the control information is a threshold value that is compared with the information about the reception quality.

[0183] In one embodiment of the present disclosure, the receiving circuit receives information used to determine whether reception of the wireless signal has been completed.

[0184] In one embodiment of the present disclosure, the information used to determine whether reception is complete indicates the number of the plurality of wireless signals.

[0185] In one embodiment of the present disclosure, the information used to determine the completion of reception is included in a Null Data Packet Announcement (NDPA) or a trigger frame.

[0186] In one embodiment of the present disclosure, the feedback setting includes setting information for identifying a source of the wireless signal.

[0187] In one embodiment of the present disclosure, the feedback configuration includes a configuration for individually transmitting feedback information for each of the plurality of sources.

[0188] In one embodiment of the present disclosure, the feedback configuration includes a configuration for sending feedback information to two or more of the sources.

[0189] A wireless communication method according to one embodiment of the present disclosure receives multiple wireless signals transmitted from multiple sources, and controls feedback settings for the multiple wireless signals according to differences in reception quality of the multiple wireless signals.

[0190] The disclosures of the specification, drawings and abstract contained in Japanese Patent Application No. 2019-157100, filed on August 29, 2019, are incorporated herein by reference in their entirety. [Industrial Applicability]

[0191] An embodiment of the present disclosure is useful in a mobile communication system. [Explanation of symbols]

[0192] 10, 100 Wireless communication control device 11, 22 Control section 12 Transmitter 101 known signal generator 102, 206 Transmission packet generation unit 103, 201 Radio transmitter / receiver 104, 202 Received packet decoding unit 20, 200 Wireless communication device 21 Receiving unit 203 Reception quality measurement unit 204 Feedback information selection unit 205 Feedback information generation unit

Claims

1. a receiving circuit for receiving a plurality of wireless signals transmitted from a plurality of transmission sources; determining a cooperative scheme to be used by the multiple transmission sources in downlink cooperative communication from a plurality of cooperative schemes including two or more of Coordinated Spatial Reuse (CSR), Coordinated Beamforming (CBF), Joint Transmission (JT), and Dynamic Point Blanking (DPB) according to reception qualities of the multiple wireless signals; a control circuit that feeds back feedback information of a type corresponding to the determined cooperation method, among a plurality of types of feedback information, to the transmission source; A wireless communication device comprising:

2. the control circuit determines the cooperation method based on a comparison result between a difference in reception quality between a first transmission source selected from the plurality of transmission sources and another second transmission source and a threshold value; The wireless communication device according to claim 1 .

3. the first transmission source is a transmission source of the wireless signal that exhibits the best reception quality among the plurality of transmission sources; The wireless communication device according to claim 2 .

4. the first transmission source is a transmission source that has established an association with the wireless communication device; The wireless communication device according to claim 2 .

5. When the determined cooperation method is the CSR, the control circuit includes, in the feedback information to be fed back to the transmission source, information on reception quality in each of a plurality of blocks obtained by dividing a frequency domain. The wireless communication device according to claim 1 .

6. receiving multiple radio signals transmitted from multiple sources; determining a cooperative scheme to be used by the multiple transmission sources in downlink cooperative communication from a plurality of cooperative schemes including two or more of Coordinated Spatial Reuse (CSR), Coordinated Beamforming (CBF), Joint Transmission (JT), and Dynamic Point Blanking (DPB) according to reception qualities of the multiple wireless signals; feeding back, to the transmission source, feedback information of a type corresponding to the determined cooperation method, among a plurality of types of feedback information; Wireless communication method.

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