Access point, terminal, and communication method

Abstract

The access point of the present application has: a transmission circuit that transmits information about a mode of a stream corresponding to an uplink signal from a terminal to the terminal; and a reception circuit that receives a signal pre-coded based on the mode.

Description

Technical Field

[0001] This disclosure relates to access points, terminals, and communication methods. Background Technology

[0002] Within the Institute of Electrical and Electronics Engineers (IEEE), the Study Group (SG) is planning to develop the IEEE 802.11bn standard (hereinafter referred to as "11bn") for next-generation Wireless Local Area Networks (WLANs) as a successor to the IEEE 802.11be standard (hereinafter referred to as "11be"). 11be is also known as "Extreme High Throughput (EHT) WLAN," or simply "EHT," while 11bn is also known as "Ultra High Reliability (UHR) WLAN," or simply "UHR." Examples of standards used in WLANs (also known as wireless LANs) include IEEE 802.11 and its revisions (IEEE 802.11ax, IEEE 802.11be, and other future standards), and IEEE 802.15.

[0003] Existing technical documents

[0004] Non-patent literature

[0005] Non-patent literature 1: IEEE 802.11-22 / 1392r0, “Beamforming Improvement for UHR”

[0006] Non-patent literature 2: IEEE 802.11-23 / 0725r0, “Uplink MU MIMO Precoding -Follow-up”

[0007] Non-patent document 3: IEEE P802.11be / D4.0

[0008] Non-patent document 4: IEEE 802.11-2020

[0009] Non-patent literature 5: IEEE 802.11-14 / 0571r12, “11ax Evaluation Methodology”

[0010] Non-patent literature 6: Daisuke Ogawa, et al., “A Low Complexity PMI / RI Selection Scheme in LTE-A systems,” VTC Spring 2013, IEEE

[0011] Non-patent document 7: IEEE 802.11-19 / 1593r3, “Joint Sounding for Multi-AP Systems”

[0012] Non-patent document 8: IEEE 802.11-19 / 0804r0, “Multi-AP Transmission Procedure” Summary of the Invention

[0013] However, the control methods for signal transmission in wireless communications such as wireless LANs (Local Area Networks) have not been fully studied.

[0014] The non-limiting embodiments of this disclosure help to provide access points, terminals, and communication methods that can improve the efficiency of transmission control in wireless communication.

[0015] An access point according to one embodiment of this disclosure includes: a transmitting circuit that transmits information about a pattern of a stream corresponding to an uplink signal from a terminal to the terminal; and a receiving circuit that receives a signal pre-coded based on the pattern.

[0016] It should be noted that these general or specific methods can be implemented by systems, devices, methods, integrated circuits, computer programs or recording media, or by any combination of systems, devices, methods, integrated circuits, computer programs and recording media.

[0017] According to one embodiment of this disclosure, for example, the efficiency of transmission control in wireless communication can be improved.

[0018] Further advantages and effects of one embodiment of this disclosure will be illustrated by the specification and drawings. These advantages and / or effects are provided by the various embodiments and the features described in the specification and drawings, but not necessarily all of them need to be provided in order to obtain one or more of the same features. Attached Figure Description

[0019] Figure 1 This is a diagram illustrating a timing example of uplink (UL) precoding.

[0020] Figure 2This is a block diagram representing a structural example of an Access Point (AP).

[0021] Figure 3 This is a block diagram representing a structural example of a terminal (STA: Station).

[0022] Figure 4 This is a block diagram representing a structural example of AP.

[0023] Figure 5 This is a block diagram representing a structural example of STA.

[0024] Figure 6 This is a diagram illustrating the timing examples of AP and STA operations.

[0025] Figure 7 This is a diagram illustrating an example of the correspondence between a P-matrix and stream numbers.

[0026] Figure 8 This is a diagram illustrating examples of stream numbering in time-division multiplexing and frequency-division multiplexing.

[0027] Figure 9 This is a diagram representing an example of a stream numbering pattern.

[0028] Figure 10 This is a diagram representing an example of a stream numbering pattern.

[0029] Figure 11 This is a diagram representing an example of a stream numbering pattern.

[0030] Figure 12 This is a diagram representing an example of a stream numbering pattern.

[0031] Figure 13 This is a diagram representing an example of a stream numbering pattern.

[0032] Figure 14 This is a diagram showing an example of the Common Info field for a trigger frame.

[0033] Figure 15 This is a diagram showing an example of the User Info field in the trigger frame.

[0034] Figure 16 This is a diagram representing an example of a Stream Number Pattern subfield.

[0035] Figure 17 This is a diagram illustrating the timing examples of AP and STA operations.

[0036] Figure 18 This is a diagram illustrating the timing examples of AP and STA operations.

[0037] Figure 19 This is a diagram illustrating the timing examples of AP and STA operations.

[0038] Figure 20 This is a diagram showing an example of the STA Info field in a Null data packet Announcement (NDPA).

[0039] Figure 21 This is a diagram illustrating an example of generating a precoder subfield.

[0040] Figure 22 This is a diagram illustrating an example of flow number notification in NDPA.

[0041] Figure 23 This is a diagram showing an example of the number of streams allocated to STA and its effect.

[0042] Figure 24 This is a diagram showing an example of the trigger type of a trigger frame.

[0043] Figure 25 This is a diagram showing an example of a general information field representing a trigger frame.

[0044] Figure 26 This is a diagram showing an example of the user information field in the trigger frame.

[0045] Figure 27 This is a diagram representing an example of the HE / EHT-LTF Symbols subfield.

[0046] Figure 28 This is a diagram illustrating the timing examples of AP and STA operations.

[0047] Figure 29 This is a diagram illustrating the timing examples of AP and STA operations.

[0048] Figure 30 This is a diagram illustrating the timing examples of AP and STA operations.

[0049] Figure 31 This is a diagram illustrating examples and effects of orthogonal resources.

[0050] Figure 32This is a diagram representing an example of a precoder type subfield.

[0051] Figure 33 This is a block diagram representing a structural example of AP.

[0052] Figure 34 This is a diagram illustrating the timing examples of AP and STA operations.

[0053] Figure 35 This is a diagram showing an example of the trigger type of a trigger frame.

[0054] Figure 36 This is a diagram showing an example of the format of a trigger frame.

[0055] Figure 37 This is a diagram showing an example of a general information field representing a trigger frame.

[0056] Figure 38 This is a diagram showing an example of the user information field in the trigger frame.

[0057] Figure 39 This is a diagram illustrating an example of a precoder calculation indication subfield.

[0058] Figure 40 This is a diagram illustrating a format example of Multi-AP (MAP) NDPA.

[0059] Figure 41 This is a diagram showing an example of the user information field in the trigger frame.

[0060] Figure 42 This is a diagram illustrating an example of a Joint Sounding subfield.

[0061] Figure 43 This is a diagram showing an example of the trigger type of a trigger frame.

[0062] Figure 44 This is a diagram showing an example of a general information field representing a trigger frame.

[0063] Figure 45 This is a diagram showing an example of the user information field in the trigger frame. Detailed Implementation

[0064] Hereinafter, various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0065] One of the key aspects of UHR is the increase in throughput at different receive quality levels (e.g., signal-to-noise ratio (SNR) levels). For this goal, for example, it is expected that beamforming (BF) will be applied to the uplink (UL) (e.g., see Non-Patent Literature 1).

[0066] Regarding the precoder used for beamforming (BF), the following method is proposed: The access point (AP, or also called a "base station") performs channel quality estimation (sounding) and UL precoder calculation based on the uplink signal (e.g., null data packet (NDP)) from the station (STA, or also called a "non-AP STA"), and notifies each STA of the UL precoder (e.g., see Non-Patent Document 2). Furthermore, the precoder is used to perform linear operations on the modulated signal, and is also referred to as a precoding matrix, beamforming matrix, or steering matrix. In Non-Patent Document 2, regarding the precoding of UL MU-MIMO (UL Multi User - Multi Input Multi Output), in... Figure 1 In the timing sequence shown, the AP (Beamformee) calculates the precoder based on the uplink signal from the STA (Beamformer) (e.g., UL sounding NDP) and notifies each STA of the precoder coefficients.

[0067] However, the control methods for UL precoding have not been fully studied.

[0068] For example, in the method of Non-Patent Document 2, there is concern about the increase in overhead (signaling overhead) when the AP notifies the precoder from each STA.

[0069] As an example of a low-overhead precoding control method, implicit feedback is specified (see, for example, non-patent document 4, “10.34.1 HT steering matrix calculations”). In this method, channel quality estimation and precoder calculation are performed based on the reciprocity of uplink and downlink (DL). However, concerns arise regarding the degradation of BF performance and reception quality when uplink and downlink reciprocity is not met. For example, conditions for the failure of uplink and downlink reciprocity include the influence of interference signals and frequency and phase errors between the transmitter (Tx) and receiver (Rx) due to insufficient calibration frequency.

[0070] In non-limiting embodiments of this disclosure, examples of precoding control methods are described to suppress the increase in overhead and to suppress the degradation of reception quality when uplink and downlink reciprocity is not met.

[0071] [Structure of a wireless communication system]

[0072] The wireless communication system of this embodiment may include, for example, AP100 and STA200. In the wireless communication system, there may be more than one AP100 and STA200.

[0073] Figure 2 This is a block diagram illustrating a structural example of AP100, an embodiment of the present disclosure. Figure 2 In the AP100 shown, the transmitting unit (e.g., corresponding to the transmitting circuit) sends information (e.g., also called the stream numbering pattern) to the STA200 regarding the pattern of the stream corresponding to the uplink signal from the STA200. The receiving unit (e.g., the receiving circuit) receives the signal (e.g., UL data) pre-coded based on the above pattern.

[0074] Figure 3 This is a block diagram illustrating a structural example of a portion of an embodiment of the STA200 of this disclosure. Figure 3 In the STA200 shown, the receiving unit (e.g., corresponding to the receiving circuit) receives information about the pattern of the stream corresponding to the uplink signal from the STA200. The transmitting unit (e.g., corresponding to the transmitting circuit) transmits a signal pre-coded based on the pattern.

[0075] (Implementation Method 1)

[0076] In this embodiment, AP100 performs UL precoding control by notifying STA200 of a control signal containing information about a pattern (hereinafter referred to as "stream number pattern") corresponding to the UL signal from STA200 (e.g., stream number).

[0077] Stream numbering patterns, for example, represent one or a combination of numbers assigned to each of several streams, which constitute (or are applied to) a UL signal. Stream numbering is, for example, determined based on the UL signal from STA200.

[0078] The stream numbering pattern may include at least one of multiple streams applied to the UL signal. For example, the stream numbering pattern may include consecutive or non-consecutive stream numbers assigned to multiple streams applied to the UL signal. A stream may be, for example, a spatial stream or a space-time stream. Hereinafter, it is assumed that the space-time stream is equal to the spatial stream without implementing space-time block coding (STBC).

[0079] Additionally, the UL signal may be, for example, a UL signal received by AP100 from STA200 (e.g., the most recently received UL signal). The UL signal may, for example, contain an NDP with a pre-encoder applied, or a signal containing data with a pre-encoder applied. Furthermore, "most recently" refers, for example, to the most recent time AP100 received a UL signal from STA200 before sending the control signal.

[0080] Additionally, the control signal may include, for example, control information for the pre-encoder applied to the UL signal. The control information may include, for example, information related to the stream numbering pattern.

[0081] The following describes a structural example of AP100 and STA200 in this embodiment.

[0082] [Structure example of AP100]

[0083] Figure 4 This is a block diagram representing a structural example of AP100.

[0084] Figure 4The AP100 shown may include, for example, a wireless transceiver unit 101, a demultiplexing unit 102, an orthogonal separation unit 103, a preamble demodulation unit 104, a channel estimation unit 105, a quality estimation unit 106, a precoder selection unit 107, a data demodulation unit 108, a data decoding unit 109, a stream numbering mode preservation unit 110, a preamble generation unit 111, a data generation unit 112, and a multiplexing unit 113.

[0085] in addition, Figure 4 The wireless transceiver unit 101 shown can be included in Figure 2 In the transmitting unit shown, Figure 4 The wireless transceiver unit 101 shown can be included in Figure 2 In the receiving section shown.

[0086] exist Figure 4 In this system, the wireless transceiver unit 101 performs wireless signal transmission and reception processing with the STA 200. For example, in the transmission processing, the wireless transceiver unit 101 performs D / A (Digital-to-Analog) conversion and up-conversion to the carrier frequency on the wireless frames output from the multiplexing unit 113, and then transmits the processed signal to the STA 200 via the antenna. Additionally, in the reception processing, the wireless transceiver unit 101 receives the signal transmitted from the STA 200 via the antenna, performs down-conversion and A / D (Analog-to-Digital) conversion, and then outputs the processed signal to the demultiplexing unit 102.

[0087] The demultiplexing unit 102 separates (or divides) the signal output from the wireless transceiver unit 101 and received from the STA 200 into a preamble section (or preamble signal) and a data section (or data signal), and outputs the preamble signal to the quadrature separation unit 103 and the data signal to the data demodulation unit 108.

[0088] The orthogonal separation unit 103 performs a Fourier transform (e.g., a Fast Fourier Transform (FFT)) on the preamble signal output from the separation unit 102 to extract control information (e.g., orthogonal resources, etc.) used in the STA 200 (e.g., the orthogonalization unit 215 described later). Then, based on the extracted control information, the orthogonal separation unit 103 separates the reference signal (e.g., training signals such as long training field (LTF) or short training field (STF)) within the preamble signal. Here, the reference signal is separated, for example, into dimensions such as the number of receiving antennas and the number of streams. The orthogonal separation unit 103 outputs the separated preamble to the preamble demodulation unit 104.

[0089] The preamble demodulation unit 104 demodulates the preamble signal output from the quadrature separation unit 103, extracts control information (e.g., bandwidth (BW) or MCS (modulation and coding scheme)) for demodulation and decoding of the data signal, and outputs it to the data demodulation unit 108. Additionally, the preamble demodulation unit 104 extracts the reference signal contained in the preamble signal and outputs the reference signal to the channel estimation unit 105.

[0090] The channel estimation unit 105 estimates the UL channel from STA200 to AP100 based on the output of the preamble demodulation unit 104. The channel estimation unit 105 performs channel estimation, for example, for each receive stream and each receive antenna. The channel estimation unit 105 outputs the derived channel estimate to the quality estimation unit 106 and the data demodulation unit 108.

[0091] The quality estimation unit 106 estimates the reception quality (e.g., SNR or SINR (signal-to-interference-plus-noise ratio)) of the signal received by the AP 100 for each stream and each receiving antenna based on the channel estimation value output from the channel estimation unit 105. As an example, when estimating SINR, the quality estimation unit 106 can use the calculation formula described in Non-Patent Document 5 to estimate each SINR for each receiving stream and each receiving antenna. The quality estimation unit 106 outputs the derived reception quality estimate to the precoder selection unit 107.

[0092] The pre-encoder selection unit 107 generates control information for AP100 to transmit to STA200 based on the received quality estimate output from the quality estimation unit 106. For example, the pre-encoder selection unit 107 may select a pre-encoder (e.g., stream numbering mode) for STA200 to transmit based on the received quality estimate. As an example, the pre-encoder selection unit 107 may optimize the transmission rank of STA200 (rank adaptation) based on the SINR output from the quality estimation unit 106. For example, rank adaptation may be a step of determining the spatial streams and / or the number of spatial streams that result in good throughput and / or communication quality (e.g., see Non-Patent Document 6). For example, the pre-encoder selection unit 107 determines the combination of stream numbers (stream numbering mode) for UL transmission in STA200 through rank adaptation and outputs the determined stream numbering mode to the stream numbering mode holding unit 110.

[0093] The data demodulation unit 108 performs an FFT on the data signal output from the demultiplexing unit 102, and performs demodulation processing based on the control information output from the preamble demodulation unit 104 and the UL channel estimate output from the channel estimation unit 105. The data demodulation unit 108 outputs the demodulated data signal obtained by demodulation to the data decoding unit 109. In addition, the data demodulation unit 108 may also output the control information output from the preamble demodulation unit 104 to the data decoding unit 109.

[0094] The data decoding unit 109 decodes the demodulated data signal output from the data demodulation unit 108 based on the output (control information) of the preamble demodulation unit 104. Furthermore, when the UL signal is a TB (Trigger Based) PPDU (Physical Layer (PHY) Protocol Data Unit), the data decoding unit 109 can retain the control information (e.g., MCS or coding type) contained in the trigger frame (signal instructing STA200 to send the TB PPDU) sent by AP100 and perform decoding based on this control information.

[0095] The stream numbering pattern holding unit 110 stores the stream numbering pattern output from the pre-encoder selection unit 107 in a storage area (e.g., a buffer). For example, when AP100 generates a control signal to notify STA200, the stream numbering pattern holding unit 110 outputs the stream numbering pattern to the data generation unit 112.

[0096] The preamble generation unit 111 generates a preamble signal (e.g., EHT-SIG, EHT-LTF, U-SIG, etc.) contained in the control signal sent from AP100 to STA200. The preamble generation unit 111 outputs the generated preamble signal to the multiplexing unit.

[0097] The data generation unit 112 generates a data signal (e.g., an NDPA (NDP Notification) frame or a trigger frame). The data signal may, for example, include a stream numbering pattern output from the stream numbering pattern holding unit 110. Here, when generating a trigger frame instructing STA 200 to send a TBPPDU, AP 100 stores the control information (e.g., MCS or encoding type) of the data signal in the TBPPDU in a storage area. The data generation unit 112 outputs the generated data signal to the multiplexing unit 113.

[0098] The multiplexing unit 113 modulates and performs inverse Fourier transform (e.g., inverse fast Fourier transform (IFFT)) processing on the preamble signal output from the preamble generation unit 111 and the data signal output from the data generation unit 112, and multiplexes them according to the format of the radio frame, and then outputs them as a radio frame to the radio transceiver unit 101. Here, the reference signal contained in the preamble signal can be orthogonalized by allocating specified orthogonal resources.

[0099] [Structure example of STA200]

[0100] Figure 5 This is a block diagram representing a structural example of STA200.

[0101] Figure 5 The STA200 shown may include, for example, a wireless transceiver unit 201, a demultiplexing unit 202, a preamble demodulation unit 203, a channel estimation unit 204, a data demodulation unit 205, a data decoding unit 206, a precoder generation unit 207, a stream numbering pattern holding unit 208, a precoder holding unit 209, a reference signal generation unit 210, a data generation unit 211, a control signal generation unit 212, a precoding matrix multiplication unit 213, a modulation unit 214, an orthogonalization unit 215, and a multiplexing unit 216.

[0102] also, Figure 5 The wireless transceiver unit 201 shown can be included in Figure 3 In the receiving section shown, Figure 5 The wireless transceiver unit 201 shown can be included in Figure 3 In the sending section shown.

[0103] exist Figure 5 In this process, the wireless transceiver unit 201 performs wireless signal transmission and reception processing with the AP100. For example, in the transmission processing, the wireless transceiver unit 201 performs D / A conversion and up-conversion to the carrier frequency on the wireless frames output from the multiplexing unit 216, and transmits the processed signal to the AP100 via the antenna. Furthermore, in the reception processing, for example, the wireless transceiver unit 201 receives the signal transmitted from the AP100 via the antenna, performs down-conversion and A / D conversion, and outputs the processed signal to the demultiplexing unit 202.

[0104] The demultiplexing unit 202 separates (or divides) the signal output from the wireless transceiver unit 201 and received from the AP100 into a preamble section (or preamble signal) and a data section (or data signal), and outputs the preamble signal to the preamble demodulation unit 203 and the data signal to the data demodulation unit.

[0105] The preamble demodulation unit 203 performs a Fourier transform (FFT) on the preamble signal output from the demultiplexing unit 202 to extract control information (e.g., BW or MCS) for demodulation and decoding of the data signal, and outputs it to the data demodulation unit 205. Furthermore, the preamble demodulation unit 203 extracts the reference signal (e.g., LTF or STF) contained in the preamble signal and outputs it to the channel estimation unit 204.

[0106] The channel estimation unit 204 estimates the channel quality based on the output of the preamble demodulation unit 203. The channel estimate derived in the channel estimation unit 204 is the channel estimate of the DL from AP100 to STA200. For example, in order to demodulate the data signal, the channel estimation unit 204 outputs the DL channel estimate to the data demodulation unit 205. Here, STA200 may, for example, assume the reciprocity of the channel between UL and DL, and derive the UL channel estimate (e.g., the channel from STA200 to AP100) from the DL channel estimate. The channel estimation unit 204 outputs the derived UL channel estimate to the precoder generation unit 207.

[0107] The data demodulation unit 205 performs an FFT on the data signal output from the demultiplexing unit 202, and performs demodulation processing based on the control information output from the preamble demodulation unit 203 and the DL channel estimate output from the channel estimation unit 204. The data demodulation unit 205 outputs the demodulated data signal obtained through demodulation to the data decoding unit 206. In addition, the data demodulation unit 205 can output the control information output from the preamble demodulation unit 203 to the data decoding unit 206.

[0108] The data decoding unit 206 decodes the demodulated data signal output from the data demodulation unit 205 based on the output (control information) of the preamble demodulation unit 203. Regarding the received data obtained through decoding, when it contains a stream numbering pattern, the data decoding unit 206 outputs the stream numbering pattern to the stream numbering pattern holding unit 208. Furthermore, when it contains control information from the pre-encoder of the AP100 (e.g., pre-encoder generation type, number of transmit streams, orthogonal resource information for the transmit streams (e.g., orthogonal code, frequency, time, etc.)), the data decoding unit 206 outputs this control information to the pre-encoder generation unit 207.

[0109] The precoder generation unit 207 generates a precoder (precoding matrix) based on the UL channel estimate output from the channel estimation unit 204 and the control information output from the data decoding unit 206. The precoder generation unit 207 outputs information about the generated precoder to be applied to the reference signal and data signal transmitted by the STA 200. For example, the precoder generation unit 207 outputs the generated precoder to the precoder holding unit so that the STA 200 can select the precoder based on the control information (stream numbering mode) from the AP 100. Furthermore, the precoder generation unit 207 determines the stream number corresponding to each stream transmitted by the UL applied to the STA 200 and outputs it to the stream numbering mode holding unit 208.

[0110] The stream number pattern holding unit 208 saves the stream numbers output from the pre-encoder generation unit 207 into a storage area (buffer). Furthermore, when a stream number pattern is output from the data decoding unit, the stream number pattern holding unit 208 extracts the stream number specified by the stream number pattern from the saved stream numbers and outputs the extracted stream number to the pre-encoder holding unit 209.

[0111] The precoder holding unit 209 saves the precoder output from the precoder generation unit 207 to the storage area. Furthermore, based on the stream number (the specified stream number) output from the stream numbering pattern holding unit 208, the precoder holding unit 209 extracts components within the precoder matrix and outputs them, for example, to the precoder matrix multiplication unit 213 (not shown). Here, the selection and extraction of components within the precoder matrix to obtain the reconstructed precoder matrix is ​​referred to as precoder reconstruction or precoder selection.

[0112] The reference signal generation unit 210 generates a reference signal (e.g., LTF, STF, etc.) included in the preamble signal of the UL signal. For the reference signal generated by the reference signal generation unit 210, it is assumed that a pre-encoder will be applied and orthogonalized in subsequent processing. For example, the reference signal generation unit 210 can generate the reference signal based on the number of streams determined by the pre-encoder generation unit 207 and the control information acquired in the data decoding unit 206 (e.g., the number of streams or frequency indicated from AP100). Furthermore, the reference signal generation unit 210 can determine the number of streams of the reference signal based on the number of stream numbers output from the pre-encoder holding unit 209 (the number of stream numbers indicated from AP100 via the stream numbering pattern) or the number of columns of the reconstructed precoding matrix. The reference signal generation unit 210 outputs the generated reference signal to the precoding matrix multiplication unit 213.

[0113] The data generation unit 211 generates data signals (e.g., MPDUs (MAC Protocol Data Units)) contained in the UL signal. For the signals generated by the data generation unit 211, it is assumed that a pre-encoder will be applied in subsequent processing; however, unlike the case of the reference signal, orthogonalization is not assumed. Furthermore, the data generation unit 211 can determine the number of data signal streams based on the number of stream numbers output from the pre-encoder holding unit 209 (the number of stream numbers indicated by the stream numbering pattern from AP100) or the number of columns of the reconstructed precoding matrix. The data generation unit 211 outputs the generated data signals to the precoding matrix multiplication unit 213.

[0114] The control signal generation unit 212 generates control signals (e.g., EHT-SIG, U-SIG, etc., excluding the reference signal) contained in the preamble signal of the UL signal. Unlike the cases of reference signals and data signals, the signals generated by the control signal generation unit 212 are not assumed to be processed by a pre-encoder or orthogonalization in subsequent processing. The control signal generation unit 212 outputs the generated control signal to the modulation unit 214.

[0115] The precoding matrix multiplication unit 213 multiplies the signals output from the reference signal generation unit 210 and the data generation unit 211 by the precoding matrix output from the precoder holding unit 209. Here, each stream and each transmit antenna is multiplied by a component of the precoding matrix that varies for each stream and each transmit antenna. The precoding matrix multiplication unit 213 outputs the signal multiplied by the precoding matrix (the precoded signal) to the modulation unit 214.

[0116] The modulation unit 214 modulates and performs inverse Fourier transform (IFFT) on the precoded signal output from the precoded matrix multiplication unit 213 and the control signal output from the control signal generation unit 212, and outputs it as a modulated signal to the multiplexing unit 216. In addition, when the precoded signal is the reference signal, the modulation unit 214 outputs the modulated signal (modulated reference signal) to the orthogonalization unit 215.

[0117] The orthogonalization unit 215 orthogonalsizes the modulation reference signal output from the modulation unit 214 using orthogonal resources. For example, when orthogonal codes (e.g., P-matrix) are used as resources, the orthogonalization unit 215 multiplies each stream of the modulation reference signal by a different orthogonal code to map it to each transmit antenna. The orthogonalization unit 215 outputs the orthogonalized modulation reference signal to the multiplexing unit 216.

[0118] The multiplexing unit 216 multiplexes the orthogonalized modulation reference signal and the modulation signal (the signal after multiplication of the data signal and the control signal by precoding matrix) in accordance with the format of the wireless frame, and outputs them as a wireless frame to the wireless transceiver unit 201.

[0119] The above describes the structural examples of AP100 and STA200.

[0120] [Operational Examples of AP100 and STA200]

[0121] The following describes the operating examples of AP100 and STA200.

[0122] [Method 1]

[0123] Figure 6 This is a timing diagram representing the operation examples of AP100 (abbreviated as AP) and STA200 (abbreviated as STA) in Method 1.

[0124] <Transmission of UL signals with pre-encoder>

[0125] exist Figure 6 In this process, the STA200 transmits UL signals with a pre-encoder applied (e.g., UL signals with multiple streams applied).

[0126] The UL signal can be, for example, a TB PPDU (e.g., a data signal) resulting from multiplying a reference signal and data by a precoding matrix, or it can be an NDP where no data is generated but only the reference signal is multiplied by a precoding matrix. An NDP multiplied by a precoding matrix is ​​sometimes referred to as a precoded NDP, a beamformed NDP, or a steered NDP.

[0127] STA200 (e.g., precoding matrix multiplication unit 213) multiplies the reference signal and data signal by a precoding matrix. The precoding matrix is ​​equivalent to a Q-matrix, for example, in the case of an STF, where Q is a variable in equations (36-35) or (36-46) as described in Non-Patent Document 3. k,u Multiplication; in the case of LTF, the variable Q is the expression in equations (36-44) or (36-45) as described in Non-Patent Document 3. k and Q k,u Multiplication; in the case of a data signal, the variable Q is the variable in equations (36-87) or (90) as described in Non-Patent Document 3. k,u Multiply.

[0128] Furthermore, STA200 (e.g., orthogonalization unit 215) orthogonalizes the reference signal. As an example, orthogonalization using orthogonal codes (P-matrix) will be explained.

[0129] The stream numbers of the respective streams constituting the UL signal can correspond, for example, to the respective rows of the P matrix included in the reference signal. The AP100 determines (or grasps) the stream numbers of the respective streams constituting the UL signal by orthogonally separating the streams corresponding to the respective rows of the P matrix. For example, the stream numbers are determined based on the uplink signal of the STA200. For example, when the UL signal uses three streams (the case of transmitting three streams), for the LTF, the P matrix (P EHT-LTF )(for example, equations (36 - 43) of Non-Patent Document 3) is used.

[0130] [Equation 1]

[0131]

[0132] When transmitting three streams, for example, as Figure 7 shown, the four values of each of the first to third rows of the P matrix are multiplied by the four LTF symbols of each stream. For example, it can be set that the streams corresponding to the first, second, and third rows of the P matrix are stream 1, stream 2, and stream 3 constituting the UL signal (for example, LTF), and the stream numbers of the respective streams are made to correspond to the first, second, and third rows of the P matrix.

[0133] In addition, it is assumed that the number of streams constituting the UL signal is determined by the AP100 based on the capability of the STA200, and the recognition of the number of streams of the UL signal is consistent between the AP and the STA.

[0134] <Receiving of UL Signal and Acquisition of Stream Number>

[0135] After receiving the UL signal, the AP100 (for example, the orthogonal separation unit 103) refers to the NSS subfield from the control signal (for example, EHT - SIG) to acquire the number of streams of the UL signal and the stream numbers corresponding to the P matrix.

[0136] The AP100 performs orthogonal separation of the reference signal based on the acquired control information.

[0137] The AP100 (for example, the preamble demodulation unit 104) demodulates the preamble signals of the respective streams after orthogonal separation. Here, when the UL signal is a signal containing data (for example, TB PPDU) and code division multiplexing is applied, the AP100 acquires the stream numbers corresponding to the P matrix in the same manner as in the case of the NDP. On the other hand, regarding the stream numbers in the case where the UL signal is a signal containing data (for example, TB PPDU) and a multiplexing method different from code division multiplexing (for example, time division multiplexing or frequency division multiplexing) is applied, Figure 8 is used for the explanation.

[0138] In Figure 8 In the case of time division multiplexing, STA200 and AP100 respectively identify the streams of each data packet continuously transmitted in time as different stream numbers and store them in a recording area (for example, stream number pattern holding units 110 and 208). For example, as Figure 8 shown, when three data packets are each transmitted from STA200 using one stream, the streams of data packets 1, 2, and 3 are respectively set to streams 1, 2, and 3. In this case, the same P matrix can be used among streams 1, 2, and 3.

[0139] In addition, for example, it can be that when three data packets are each transmitted using two streams, the stream of data packet 1 is set to streams 1 and 2, the stream of data packet 2 is set to streams 3 and 4, and the stream of data packet 3 is set to streams 5 and 6. Here, the difference in the rows of the aforementioned P matrix can be used to identify which are the stream numbers within the same data packet (for example, streams 1 and 2 within data packet 1).

[0140] In addition, in Figure 8 an example of setting a gap (no transmission interval) of a specified time to transmit a data packet is described, but it is not limited to this. It is also possible to continuously transmit data packets of a specified length without setting a gap interval.

[0141] In Figure 8 in the case of frequency division multiplexing, STA200 and AP100 respectively identify the streams of signals transmitted in different frequency bands (or frequency resources) as different stream numbers and store them in a recording area (for example, stream number pattern holding units 110 and 208).

[0142] In addition, the frequency band can be, for example, a resource unit (RU: Resource Unit) or a resource in terms of tones. In addition, for example, it is also possible to aggregate multiple tones separated by a specified tone interval into one stream.

[0143] For example, in Figure 8 when the frequencies are set to RU1 < RU2 < RU3 and one stream is transmitted in each RU when transmitted from STA200, as the stream number, the stream of RU1 can be set to stream 1, the stream of RU2 can be set to stream 2, and the stream of RU3 can be set to stream 3. In addition, for example, it can also be that in the frequencies of RU1 > RU2 > RU3, the stream numbers of the streams of RU1, 2, and 3 are respectively set to streams 1, 2, and 3.

[0144] Further, for example, in the case of frequencies where RU1 < RU2 < RU3, when transmitting two streams in each RU, the streams of RU1 can be set as streams 1 and 2, the streams of RU2 can be set as streams 3 and 4, and the streams of RU3 can be set as streams 5 and 6. Here, similar to the case of time division multiplexing, the difference in the rows of the aforementioned P matrix can be used to identify which are the stream numbers within the same RU (e.g., streams 1 and 2 within RU1).

[0145] AP100 (e.g., the channel estimation unit 105) estimates the UL channel between the AP and the STA for each stream and each receiving antenna based on the orthogonally separated reference signal (e.g., LTF). Further, AP100 (e.g., the quality estimation unit 106) estimates the reception quality for each stream and each receiving antenna using the estimated UL channel. As an example, in reception quality estimation, AP100 can use the calculation formula described in Non-Patent Document 5 to calculate the SINR for each stream and each receiving antenna.

[0146] <Determination of stream number pattern>

[0147] AP100 (e.g., the precoder selection unit 107) uses the calculated reception quality (e.g., SINR) to determine the stream number pattern. The stream number pattern can, for example, include at least one of the multiple streams constituting the UL signal. For example, the stream number pattern can include consecutive or non-consecutive stream numbers among the stream numbers of the multiple streams constituting the UL signal. For example, a rank adaptation method can be applied to determine the stream number pattern.

[0148] As an example, the case where STA200 transmits a UL signal using three streams and AP100 selects streams 1 and 3 as the combination of stream numbers (stream number pattern) with the maximum capacity (Capacity) through rank adaptation aiming at maximizing Capacity (communication capacity) is described.

[0149] In this case, AP100 (the stream number pattern holding unit 110) stores the stream numbers 1 and 3 obtained through rank adaptation in the storage area and outputs the stream number pattern including stream numbers 1 and 3 to the preamble generation unit 111 and the data generation unit 112.

[0150] AP100 (e.g., the data generation unit 112) generates a control signal (e.g., a trigger frame) for notifying the determined stream number pattern and causing STA200 to transmit UL data.

[0151] Hereinafter, an example of a method for notifying the stream number pattern using a control signal is described.

[0152] (1) Method using a bitmap:

[0153] The AP100 uses multiple bits within the control signal to indicate the use / disuse of multiple streams through the value of each bit (0 or 1). For example, when the STA200 transmits UL signals using four streams (streams 1-4) and the AP100 determines the stream numbering mode as streams 1, 3, and 4, the bitmap is set to "1011". Here, each bit, from left to right, indicates the use / disuse of streams 1-4, with 1 indicating "use" and 0 indicating "disuse". After receiving the bitmap "1011", the STA200 will use streams 1, 3, and 4 in the next UL data transmission. Alternatively, a 6-bit bitmap can be used when the UL signal uses six streams, allowing the number of bits in the bitmap to be variably set according to the number of streams.

[0154] (2) Method for using a common form between AP100 and STA200:

[0155] A common table (common table) is predefined between AP100 and STA200. AP100 notifies STA200 of the value corresponding to the common table via control signals. As an example, Figure 9 This illustrates an example of using a common table of 3 bits when UL signals use 4 streams. Figure 9 In the example, 8 stream numbering patterns can be communicated using 3 bits (values ​​from 0 to 7).

[0156] Additionally, for example, when using 4 bits in a common table (not shown), the AP100 and STA200 are able to cover all stream numbering patterns for transmitting and receiving UL signals using 4 streams (same as the bitmap method in (1)). For example, when defining the table by a number of bits less than the number of streams, such as Figure 9 As shown, signaling load can be reduced by changing (or omitting) a portion of the flow numbering pattern. For example, in Figure 9 In the example, the pattern with a stream count of 1 is limited to stream 1, and the cases of other streams are omitted.

[0157] In addition, common forms can be specified (defined) in the standard, or they can be notified from AP100 to STA200.

[0158] (3) Using different tables based on the number of flows:

[0159] Similar to the method of using a common table in (2), a table for the flow numbering pattern is defined. In (3), the size of the table varies (with some changes) for each flow number. Figures 10-13 Examples of tables showing the flow numbering patterns for flow numbers 1 to 4 are provided. Figures 10-13 In the example, a stream numbering pattern is defined that uses the same number of bits (1 to 4 bits) as stream numbers 1 to 4.

[0160] Therefore, the signaling load of the table can be reduced based on the number of flows.

[0161] Alternatively, similar to the method in (2) using a common table, a table corresponding to the number of bits less than the stream number can be defined. In this case, for example, by... Figures 10-13 Changing (or omitting) a portion of the flow numbering patterns defined in the table shown can reduce the number of flow numbering patterns.

[0162] Alternatively, the form can be specified (defined) in the standard, or it can be notified from AP100 to STA200.

[0163] (4) Using bitmaps when the number of streams is small:

[0164] For example, in the method of using different tables according to the number of flows in (3), in such a case... Figure 10 and Figure 11 In cases with a small number of streams (e.g., fewer than 2 streams), tables are not required; instead, stream usage / disuse can be indicated via bitmaps (0 / 1 values) corresponding to each stream, as in (1). Conversely, in cases with a large number of streams (e.g., more than 2 streams), tables can be used (e.g., ...). Figure 12 , Figure 13 This is used to notify the stream numbering pattern.

[0165] <Basic Triggering of Notification Stream Numbering Pattern>

[0166] Regarding the notification examples of the stream numbering modes in (1) to (4) above, a method for notifying the stream numbering mode is explained by using the BasicTrigger (the trigger frame of the basic type) as a control signal and extending the format of the BasicTrigger.

[0167] Figure 14 This shows an example of the format of the general information field in the basic trigger of EHT. Figure 15 This shows an example of the format of the user information field in the basic trigger of EHT.

[0168] In general information, for example, a single bit in the Reserved field may be extended. Figure 14 In the example, the 1-bit reserved field of B63 is used for stream number pattern notification. This 1-bit is used, for example, to indicate to STA200 whether to interpret user information as a stream number pattern notification. For example, the subfield name of this 1-bit could be set to "Stream Number Pattern". Figure 16 This shows the processing content of the stream number pattern subfield. For example... Figure 16As shown, when the value of the stream numbering mode subfield is 0, the user information field is interpreted without being repurposed, and when the value of the stream numbering mode subfield is 1, the user information field is interpreted after being repurposed.

[0169] In addition, when the trigger type is not a basic trigger, the stream numbering mode subfield can be set in the reserved field.

[0170] For example, when the value of the stream numbering mode subfield is 1, STA200 interprets 4 bits of the user information field shown (as an example, B25, B30, B31, and B5 of the Trigger Dependent User Info) as the stream numbering mode. Among these 4 bits, for example, the stream numbering mode can be notified based on one of the methods (1) to (4) above. Figure 15 In the basic trigger, the extensible bits are the 4 bits shown. Therefore, for example, when notifying the stream numbering mode using 5 bits or more, it can be handled by adding a new trigger type, or by further interpreting a part of the existing field (such as RU Allocation) as the stream numbering mode notification.

[0171] In the basic trigger, the extensible bits are Figure 15 the 4 bits shown. Therefore, for example, when the stream numbering mode notification uses 5 bits or more, it can be handled by adding a new trigger type, or by further interpreting a part of the existing field (such as RU Allocation) as the stream numbering mode notification.

[0172] <Transmission Timing of Control Signal>

[0173] In Figure 6 , AP100 generates a basic trigger (including the stream numbering mode) as a control signal and sends the basic trigger to STA200. In addition, STA200 receives the basic trigger from AP100.

[0174] Here, the transmission of the UL signal and the transmission of the basic trigger (control signal) can be carried out in different transmission opportunities (TXOPs). Or, the transmission of the UL signal and the basic trigger can also be carried out in the same transmission opportunity. When the UL signal and the basic trigger are transmitted in the same transmission opportunity, as Figure 17 shown, a fixed time (such as a short interframe space (SIFS)) can be set between the UL signal and the basic trigger (for example, the ellipsis part in Figure 6 ).

[0175] <STA's Basic Trigger Reception and Stream Numbering Mode Acquisition>

[0176] Figure 6The STA200 shown (e.g., the demultiplexing unit 202 and the preamble demodulation unit 203) separates the received basic trigger into a preamble signal and a data signal, and demodulates them separately.

[0177] The STA200 (e.g., the data demodulation unit 205 and the data decoding unit 206) demodulates and decodes the data signal based on the control information obtained when demodulating the preamble signal, and obtains the stream numbering pattern contained in the data signal.

[0178] The STA200 (e.g., the stream number pattern holding unit 208) compares the acquired stream number pattern with the stream numbers of the stored UL signals and outputs the corresponding stream number to the pre-encoder holding unit 209 and the pre-encoder matrix multiplication unit 213. Based on the acquired stream number, the STA200 (e.g., the pre-encoder matrix multiplication unit 213) extracts the pre-encoder for UL data transmission (response to basic triggering).

[0179] Additionally, the STA200 can determine the rank, for example, based on the number of stream numbers (or stream count) contained in the acquired stream numbering pattern.

[0180] As an example, this describes the operation of a STA200 with three transmit antennas transmitting UL signals using three streams (e.g., streams 1, 2, and 3), and obtaining the stream numbering pattern representing stream numbers 1 and 3 from the AP100.

[0181] Equation (2) shows the pre-encoder W of STA200 applied to UL signals.

[0182] [Equation 2]

[0183]

[0184] When streams 1 and 3 are selected in AP100, in UL data transmission, the second column of equation (2) is deleted, and the pre-encoder W' shown in equations (3) and (4) is applied.

[0185] [Formula 3]

[0186]

[0187] [Formula 4]

[0188]

[0189] When applying W' to UL data, similar to the application of the pre-encoder via the Q matrix described above, each transmission stream of UL data is multiplied by its respective component.

[0190] In this way, AP100 informs STA200 of the stream numbering pattern corresponding to the pre-encoder used for the UL signal. For example, AP100 implicitly indicates the pre-encoder.

[0191] For example, in the method described in Non-Patent Document 2, the AP notifies the STA of the precoder (e.g., the precoding matrix). Here, since the size of the precoder varies depending on the number of UL signal streams or the number of transceiver antennas, there is concern that the overhead of precoder notification may increase. To address this, in Method 1, the AP100 notifies the STA200 of the stream numbering pattern corresponding to the precoder (e.g., the stream number) for a precoder previously generated by the STA200. By notifying the stream numbering pattern, the signaling overhead associated with precoder notification can be reduced.

[0192] Furthermore, in implicit feedback, a precoding method with relatively low overhead, channel quality estimation and precoder calculation are performed assuming reciprocity between uplink and downlink. Here, in implicit feedback, there is concern that if reciprocity between uplink and downlink does not hold, differences in quality determination between the STA and AP for each stream will arise, leading to degraded precoder performance (or reception quality). To address this, in method 1, AP100 receives UL signals transmitted from STA200, estimates the quality of each stream of the received UL signals, and determines (or selects) the precoder used for UL data transmission based on the quality estimation results. Thus, for example, AP100 notifies STA200 to set the coefficients (e.g., columns) of the precoder applied to streams with poor quality to an unused (removed) stream numbering pattern, thereby improving reception quality even if reciprocity between uplink and downlink does not hold.

[0193] Furthermore, in Method 1, the stream numbering pattern can include non-contiguous stream numbers. For example, in the method of notifying the number of streams from AP100 to STA200, STA200 applies a precoder to the number of notified streams sequentially, starting from the stream with the starting number. In contrast, in Method 1, because the stream numbering pattern includes non-contiguous stream numbers, the combination (pattern) of stream numbers that AP100 can use for quality estimation increases, thus enabling the selection of stream numbers with better reception quality.

[0194] In addition, such as Figure 18 As shown, the basic trigger transmission by AP100 and the UL data transmission by STA200 can be performed multiple times. In this case, the second and subsequent basic triggers can be associated with the most recently precoded NDP. Alternatively, there can be no second and subsequent basic triggers, and STA200 can use the information from the first basic trigger to perform the second and subsequent data transmissions.

[0195] [Method 2]

[0196] In method 2, AP100 sends a signal (e.g., NDPA) instructing the precoder to be generated and a training signal (e.g., NDP) to STA200, thereby instructing STA200 on UL channel estimation and precoder generation.

[0197] In addition, after sending NDPA and NDP, AP100 notifies STA200 of the control signal (e.g., trigger frame) that instructs the transmission of the UL signal.

[0198] The STA200 uses the training signal to estimate the channel estimate, generates a precoder based on the channel estimate, and applies the precoder to transmit the UL signal. Here, the UL signal transmitted by the STA200 can be an NDP (precoded NDP) with the precoder applied.

[0199] The AP100 uses a UL signal with a pre-encoder applied, sent from the STA200, to determine the stream numbering pattern.

[0200] [Operation example 2-1]

[0201] Figure 19 This is a timing diagram representing the operation examples AP100 (abbreviated as AP) and STA200 (abbreviated as STA) in operation example 2-1 of method 2.

[0202] <Precoder generation of STA according to AP instructions>

[0203] AP100 (e.g., data generation unit 112) generates a generated NDPA frame for instructing the precoder to STA200. Figure 20 This shows an example of the format of the STA information field in an NDPA frame.

[0204] For example, in method 2, for Figure 20 The fields B20 to B24 shown are expanded. For example, 1 bit of B20 (reserved) notifies STA200 that after AP100 sends NDPA and NDP, it will continue to send a trigger frame indicating the transmission of precoded NDP. As an example, this subfield name is defined as the "Generate Precoder" subfield. Figure 21 Examples of the processed content corresponding to the values ​​(e.g., 0 or 1) of the generated precoder subfields are shown.

[0205] exist Figure 21 When the value of the precoder subfield generated in the AP100 is 1, the AP100 will... Figure 20The fields B21 to B24 shown indicate the scheduling results of the UL signals sent by STA200. For example, the number of streams, i.e., the size of the pre-encoder generated by STA200, can be allocated (scheduled) in B21 to B24.

[0206] In addition, Figure 21 If the value of the precoder subfield generated in the middle is 0, AP100 can not... Figure 20 The fields B21 to B24 shown indicate the scheduling results of the UL signals sent by STA200. For example, information from the Nc Index subfield can be included in B21 to B24.

[0207] In addition, such as Figure 20 As shown, prior to the expansion, B21–B24 were assigned an Nc index subfield. This subfield represents the number of columns in the compressed beamforming feedback matrix (e.g., see section 9.4.1.67 of Non-Patent Document 3). In Method 2, since AP100 informs STA200 of the stream numbering pattern instead of the compressed beamforming feedback matrix, the information in the Nc index subfield may not be required.

[0208] Figure 22 Showing the setting in Figure 20 Examples of the correspondence between values ​​in B21 to B24 and control values ​​(e.g., the number of UL signal transmission streams) are shown. Furthermore, Figure 23 Examples of the number of streams assigned to STA200 and their effects are shown.

[0209] like Figure 19 As shown, AP100 (e.g., preamble generation unit 111 or data generation unit 112) generates NDP after transmitting NDPA and then transmits NDP.

[0210] The STA200 (e.g., demultiplexing unit 202, preamble demodulation unit 203, and data demodulation unit 205) separates the NDPA transmitted from the AP100 into a preamble signal and a data signal, and demodulates them separately. The STA200 (e.g., data decoding unit 206) decodes the NDPA frame of the data signal. When decoding the NDPA frame, if a value of 1 is obtained in the precoder subfield, the STA200 interprets B21 to B24 of the NDPA frame as the stream number and retains that value.

[0211] Furthermore, when an NDP is received after receiving an NDPA, the STA200 (e.g., the preamble demodulation unit 203 and the channel estimation unit 204) demodulates the NDP and performs a quality estimation of the DL channel based on the reference signal contained in the NDP.

[0212] Here, it is assumed that UL and DL have channel reciprocity, and STA200 can estimate the quality of the UL channel from the quality estimate of the DL channel. Under the assumption of reciprocity between UL and DL, the UL channel can be derived using equation (5). In equation (5), H... UL H represents the estimated channel matrix of UL. DL This represents the estimated channel matrix for DL.

[0213] [Formula 5]

[0214]

[0215] STA200 (e.g., pre-encoder generation unit 207) is based on the estimated UL channel (H UL ) and generate UL pre-encoders from the stream number notified by AP100.

[0216] Here, it could be, for Figure 23 For each assigned stream number shown, the STA200 generates a UL pre-encoder in the following manner.

[0217] (1) The case where the number of allocated streams is the maximum number of streams in MIMO:

[0218] The STA200 is used in conjunction with the maximum number of MIMO streams to generate a precoder.

[0219] (2) The case where the number of allocated streams is greater than the maximum number of streams in MIMO:

[0220] The STA200 generates a precoder by allocating the number of streams based on the number of precoder generation methods maintained by the STA200.

[0221] As an example, let's consider the STA200, which has a maximum of 2 MIMO streams and employs three precoder generation methods: identity matrix, ZF (ZeroForcing), and MRC (Maximum Ratio Combination). The STA200 is notified via NDPA that it has been allocated 6 streams. In this case, the STA200 uses two streams to generate the identity matrix, ZF, and MRC precoders respectively. These precoders are multiplexed using orthogonal codes and transmitted via a single UL signal. Furthermore, the allocation of the allocated streams notified from the AP100 is not limited to the above example. For instance, under the same conditions, the STA200 could also use three streams to generate the ZF precoder, two streams to generate the MRC precoder, and one stream to generate the identity matrix precoder. Alternatively, it could use three streams to generate both the ZF and MRC precoders separately, without generating the identity matrix precoder.

[0222] Therefore, the AP100 can select the stream number across precoders, so it is not necessary to know the type of precoder that the STA200 is used for UL signals.

[0223] (3) The case where the number of allocated streams is less than the maximum number of streams in MIMO:

[0224] The STA200 generates a precoder based on the number of streams notified.

[0225] The above illustrates examples of UL precoder generation that vary depending on the number of allocated streams.

[0226] STA200 (e.g., precoder holding unit 209 and stream numbering mode holding unit 208) stores the generated precoder and the stream number according to the number of transmitted streams.

[0227] <Signal transmission for controlling UL signals>

[0228] like Figure 19 As shown, after sending NDPA and NDP, AP100 (e.g., data generation unit 112) generates a trigger frame to instruct STA200 to send the UL signal (pre-encoded NDP) and sends the trigger frame.

[0229] Here, for example, as a new trigger type for trigger frames, a new "Precoded ULSignal Trigger" has been added. Figure 24 An example is shown that the trigger type includes the contents of the existing trigger type subfield (e.g., see Non-Patent Document 3) and the newly added "precoded UL signal trigger".

[0230] Figure 25 This shows an example of a general information field triggered by a precoded UL signal. Figure 26 This shows an example of a user information field triggered by a precoded UL signal.

[0231] exist Figure 25 In the general information fields shown, in the indication sent by NDP without accompanying data, the existing general information fields (e.g., Figure 14The following subfields in (e.g., control information related to data generation) are set to reserved: ULBW, GI and HE / EHT-LTF Type / TriggeredTXOP Sharing Mode, LDPC Extra Symbol Segment, Pre-FEC Padding Factor, PE Disambiguity, UL Spatial Reuse, Special User Info Field Flag, EHT Reserved, and Trigger Dependent Common Info.

[0232] For example, the UL BW subfield is a subfield representing the bandwidth of the TB PPDU. Since the STA200 transmits the UL signal based on the bandwidth of the AP100's NDP, therefore... Figure 25 In the middle, set the UL BW subfield as reserved.

[0233] Additionally, for example, the GI And HE, EHT-LTF type, and triggered TXOP sharing mode subfields are information related to TBPPDU and TXOP sharing, therefore in Figure 25 The middle setting is reserved.

[0234] Additionally, for example, the FEC pre-fill factor subfield and the PE disambiguation subfield contain information related to MU PPDU and TB PPDU, so they are reserved.

[0235] Additionally, for example, since space reuse is not considered in this embodiment, the UL space reuse subfield is set as reserved.

[0236] Additionally, for example, since the Special User Info field is not used in this embodiment, the Special User Info field identifier subfield is set to reserved.

[0237] Additionally, for example, the trigger-related general information subfield is not used in this embodiment.

[0238] exist Figure 26 The user information fields shown will include the existing basic triggered user information fields (e.g., Figure 15The following subfields in ) are set as reserved: UL FEC Coding Type, UL EHT-MCS, PS160, and Trigger Dependent User Info.

[0239] For example, the UL FEC encoding type subfield and the UL EHT-MCS subfield are information related to the TB PPDU, so they are reserved.

[0240] Additionally, for example, since the STA200 transmits UL signals based on the NDP band of the AP100, therefore in Figure 26 In the middle, set the PS160 subfield as reserved.

[0241] Additionally, for example, the triggering of related user information subfields is not used in this implementation.

[0242] in addition, Figure 25 and Figure 26 The subfields that are the same as those in the existing general information fields and existing user information fields (e.g., UL length) have the same functions and processing content as in the prior art.

[0243] Figure 27 It shows Figure 25 This example illustrates the correspondence between the values ​​of the "Number Of HE / EHT-LTF Symbols" subfield in the General Information field and the corresponding content. Figure 27 In this context, the existing content is expanded by adding values ​​5 and 6 (e.g., 12-bit and 16-bit).

[0244] In the above extension, the P matrix size (LTF symbol count × LTF symbol count) is increased, with the aim of improving throughput by increasing the number of reusable STAs and streams.

[0245] In addition, regarding Figure 27 The EHT-LTF symbol used as the LTF symbol in the EHT version can also be set as "UHR-LTF symbol" in the case of the UHR version.

[0246] In addition, compared with existing user information fields, Figure 26 The number of bits in the SSAllocation field and the Number of Spatial Streams subfield of the user information field shown has been expanded. This expansion is a simple expansion that changes the maximum number of spatial streams that a STA200 can send from the existing 4 to 16.

[0247] Thus, the number of UL signals is notified, for example, via NDPA (B21-B24) or precoded UL signal triggering (spatial stream count subfield). Alternatively, in the case of notification via NDPA, the value of the spatial stream count subfield for precoded UL signal triggering may be ignored, or set to the same value as set in NDPA.

[0248] <Pre-encoded NDP transmission and stream numbering mode determination>

[0249] like Figure 19 As shown, when the STA200 receives a precoded UL signal trigger, it uses the generated precoder to generate a precoded NDP (UL signal) and sends the generated precoded NDP to the AP100. For example, the STA200 (e.g., the reference signal generation unit 210 and the precoded matrix multiplication unit 213) applies the generated precoder to the generated reference signal.

[0250] Upon receiving the precoded NDP from STA200, AP100, similar to Method 1, estimates the channel and receive quality of each stream of the precoded NDP and determines the stream numbering pattern. Then, AP100, for example, uses a basic trigger to notify STA200 of the stream numbering pattern. STA200 applies a precoder to transmit UL data based on the stream numbering notified via the stream numbering pattern.

[0251] In Operation Example 2-1, since the number of UL signal streams can be set to be greater than or less than the maximum number of MIMO streams, various precoder types can be applied, and the number of STAs that can multiplex UL signal transmissions can be increased.

[0252] For example, when using multiple precoders (e.g., when the number of streams allocated exceeds the maximum number of streams for MIMO), the AP100 can select the stream with better (e.g., best) reception quality across different categories of precoders.

[0253] Additionally, for example, when the number of STAs performing UL signal multiplexing is increased (e.g., when the number of allocated streams is less than the maximum number of MIMO streams), AP100 notifies the number of streams via NDPA, thereby scheduling multiple STA200s and improving the overall throughput of the wireless communication system.

[0254] Additionally, the AP100 notifies the STA200 in advance via NDPA whether a precoded UL signal will follow the NDP trigger, thus, as Figure 19As shown, the STA200 can begin generating a precoder immediately upon receiving the NDP, that is, before the precoded UL signal is triggered. Therefore, for example, even STAs with low processing power can increase the likelihood of generating a precoder before the UL signal is transmitted.

[0255] In addition, the STA200 can also generate a precoder based on a training signal (e.g., LTF) sent simultaneously with the control signal (e.g., trigger frame) sent from the AP100. Figure 28 An example of the timing in this case is shown. In this case, AP100 instructs STA200 to generate the pre-encoder and send the UL signal via a control signal (triggered by the pre-encoded UL signal).

[0256] Additionally, the AP100 can use the identity matrix as a precoding matrix for both the reference and data signals, enabling the STA200 to generate a precoder based on the training signal. This reduces the overhead of the NDPA and NDP sections.

[0257] Additionally, the precoded UL signal triggering in Method 2 can also be used in conjunction with the BFRP (BF Report Poll) trigger. For example, it can also be applied... Figure 29 The timing sequence is shown.

[0258] [Operation example 2-2]

[0259] Figure 30 This is a timing diagram representing the operation examples AP100 (abbreviated as AP) and STA200 (abbreviated as STA) in operation example 2-2 of method 2.

[0260] In Operation Example 2-2, STA200 transmits more than one data packet (UL signal) based on the control signal (pre-encoded UL signal trigger) used in Operation Example 2-1. At this time, STA200 can transmit data packets using different pre-encoders applied to each data packet. AP100 selects the data packet with the best reception quality and the stream numbering mode. Figure 30 In the example, the STA200 sends three data packets in time-division multiplexing mode.

[0261] <Instructions generated by the pre-encoder>

[0262] In Operation Example 2-2, similar to Operation Example 2-1, AP100 instructs STA200 to generate a precoder by sending NDPA and NDP.

[0263] After receiving the NDP, STA200 performs channel estimation and generates a precoder based on the flow count notified by NDPA. At this point, the type of precoder generated by STA200 and the number of data packets transmitted can depend on the implementation or capabilities of STA200 (which are already shared between AP-STAs). Furthermore, the number of data packets transmitted can be notified to STA200 from AP100, for example, via NDPA or a trigger frame.

[0264] In addition, it is assumed that the flow count for each packet is the same (e.g., the number notified by NDPA). Alternatively, the flow count for each packet can also be different.

[0265] STA200 (e.g., stream number pattern holding unit 208) stores stream numbers that are all different across precoders as stream numbers corresponding to each precoder.

[0266] STA200 (e.g., precoder holding section 209) stores all generated precoders.

[0267] After sending the NDP, the AP100 generates a precoded UL signal trigger and sends the generated precoded UL signal trigger to the STA200.

[0268] <Sending data packets>

[0269] When the STA200 receives a precoded UL signal trigger, it applies the generated precoder to each data packet. For example, the STA200 (e.g., the reference signal generation unit 210 and the control signal generation unit 212) generates reference signals and control signals to be included in the data packets. Furthermore, the STA200 (e.g., the precoded matrix multiplication unit 213) applies the generated precoder to the reference signals of each data packet.

[0270] The STA200 (e.g., orthogonalization unit 215) orthogonalizes the reference signal contained in the stream of each data packet by multiplying it by an orthogonal code. The orthogonal codes used between data packets may be the same or different.

[0271] STA200 will send the data packets generated through the above operations to AP100.

[0272] <Packet Reception and Stream Number Acquisition>

[0273] When AP100 (e.g., channel estimation unit 105, quality estimation unit 106, and precoder selection unit 107) receives a data packet from STA200, it estimates the channel and reception quality of each stream in the same manner as in method 1, and determines the stream numbering pattern for each data packet.

[0274] At this point, AP100 compares the reception quality (e.g., capacity) among the data packets and informs STA200 of the flow numbering pattern of the data packet with the best reception quality.

[0275] For example, when STA200 sends three data packets (e.g., data packet 1, data packet 2, and data packet 3) using three streams respectively, the stream numbering pattern is determined from the stream numbers 1, 2, and 3 of data packet 1, the stream numbers 4, 5, and 6 of data packet 2, and the stream numbers 7, 8, and 9 of data packet 3, and the STA200 is notified.

[0276] In addition, as another notification method, AP100 can notify the field representing the packet number and the field representing the flow number separately. For example, in the case of the above example of 3 flows and 3 packets, AP100 can notify STA200 of the flow number pattern including packet 1 and flows 1 and 2.

[0277] The STA200 uses a pre-encoder based on the flow numbering pattern notified from the AP100 to send UL data.

[0278] In Operation Example 2-2, STA200 sends one or more UL signals based on the control information notified by AP100, thereby enabling AP100 to select the precoder category and stream number that are optimal for reception.

[0279] Alternatively, the transmit antenna of the STA200 can be made different for each data packet (e.g., called antenna selecting), and the AP100 can select the transmit antenna that is optimal for reception based on the stream numbering pattern.

[0280] Furthermore, the multiplexing method for transmitting multiple data packets is not limited to time division multiplexing; for example, frequency division multiplexing can also be used, combining other orthogonal resources with orthogonal codes. Information related to orthogonal resources can be notified to STA200 from AP100, for example. Thus, AP100 can select the orthogonal resources (e.g., time resources or frequency resources) that are optimal for reception. Figure 31 Examples of orthogonal resources contained in control signals and their effects are shown.

[0281] Furthermore, for example, AP100 can also directly inform STA200 of the precoder category and control it to form the beam optimal for reception in AP100. For example, this can be achieved through STA information in NDPA (e.g., Figure 20 ) or user information triggered by pre-coded UL signals (e.g., Figure 26In the documentation, a new subfield (e.g., 3 bits) is added to indicate the precoder category. This new subfield can be named, for example, "Precoder Type". Figure 32 An example illustrating the correspondence between the values ​​of the precoder type subfield and the content is shown. The precoder type subfield may contain values ​​indicating that the AP100 does not specify a precoder category but the STA200 generates the precoder (e.g., Figure 32 (The value is 0). In addition, AP100 can determine the category of precoder to be notified based on the capability information of STA200.

[0282] Furthermore, the capabilities of STA200 (e.g., the method of generating the precoder) can be shared between AP-STA at the beginning of the aforementioned timing by methods such as notifying AP100 from STA200 when associated with AP100, notifying separately via PPDU, or by defining notifications via specifications or beacons.

[0283] The STA200 generates a pre-encoder based on the notified pre-encoder category and stream number, multiplies it with the UL signal, and sends it.

[0284] Furthermore, AP100 can assign multiple user information fields to a single STA200, each indicating multiple precoder categories to be notified. In this case, STA200 can generate data packets based on Operation Example 2-2, using the multiple precoder categories indicated by AP100, and multiplex them using orthogonal resources such as time or frequency.

[0285] The above describes the operating examples of AP100 and STA200.

[0286] Thus, in this embodiment, AP100 sends the stream numbering pattern corresponding to the UL signal from STA200 to STA200, and receives the UL data pre-encoded based on the stream numbering pattern in STA200. Furthermore, STA200 receives the stream numbering pattern corresponding to the UL signal from STA200, and sends the UL data pre-encoded based on the received stream numbering pattern.

[0287] Therefore, AP100 only needs to notify STA200 of the pattern of the stream number corresponding to the UL signal (e.g., the stream constituting the UL signal) from STA200, thus suppressing the increase in overhead compared to notifying STA200 of the precoder determined by AP100. Furthermore, AP100 can determine the stream number (or precoder) based on the reception quality of the UL signal, thus suppressing reception quality degradation even when reciprocity between uplink and downlink is not met. Therefore, according to this embodiment, the efficiency of transmission control in wireless communication can be improved.

[0288] (Implementation Method 2)

[0289] [Structure of a wireless communication system]

[0290] The wireless communication system of this embodiment may include, for example, AP100a and STA200. There may be more than two AP100a and STA200 in the wireless communication system.

[0291] [Structure example of AP100a]

[0292] Figure 33 This is a block diagram illustrating a structural example of AP100a according to this embodiment. AP100a differs from Embodiment 1 in that it includes a MAP (Multi-AP) control unit 114.

[0293] exist Figure 33 In this process, the MAP control unit 114 instructs the data generation unit 112 to generate control signals (e.g., also known as trigger frames or MAP triggers) for coordination between APs in MAP coordination or signals to be transmitted for MAP coordination (e.g., NDPA).

[0294] [Structure example of STA200]

[0295] The structure of STA200 in this embodiment can be the same as that of STA200 in embodiment 1 (for example, Figure 5 (The same structure)

[0296] [Operating Examples of AP100a and STA200]

[0297] The following describes operating examples for AP100a and STA200.

[0298] [Method 3]

[0299] Figure 34 This is a timing diagram representing the operation examples of AP100a (abbreviated as AP) and STA200 (abbreviated as STA) in method 3.

[0300] exist Figure 34In the example, the Sharing AP is set as AP1, the Shared AP is set as AP2, and the STAs 200 respectively connected to AP1 and AP2 are set as STA1 and STA2.

[0301] In Method 3, the MAP coordinates the Joint NDP sounding during transmission (for example, refer to Non-Patent Documents 7 and 8).

[0302] As Figure 34 shown, in Method 3, between the coordinated APs, the Sharing AP sends a MAP Trigger to the Shared AP. When the Shared AP receives the MAP Trigger, it simultaneously sends a MAP NDPA, a MAP NDP, and a precoded UL signal trigger (for example, the same as in Method 2) to each STA 200 (the STA 200 connected to the Sharing AP and the Shared AP).

[0303] Thereby, channel estimation can be performed between the Sharing AP and the Shared AP and the STAs 200 connected to each AP. In addition, by sending and sharing the information related to the reception quality measured in the Shared AP to the Sharing AP, the outflow number pattern (selecting the precoder of the STA) can be determined in a manner that optimizes reception in multiple APs 100a.

[0304] <Generation of MAP Trigger>

[0305] The Sharing AP (for example, the data generation unit 112) generates a MAP Trigger.

[0306] The MAP Trigger, for example, requests the Shared AP to send the same NDPA as in Method 2 (the NDPA indicating that the STA 200 generates a precoder).

[0307] In addition, the signal (MAP Trigger) requesting the transmission of the same NDPA as in Method 2 can also be a control frame different from the trigger frame, or other newly defined signals. In this case, the control frame can contain the information (for example, subfield) requesting the transmission of the same NDPA as in Method 2.

[0308] In Method 3, the advantage of using the trigger frame is that it can share the transmission opportunity (TXOP sharing) with more than one Shared AP, and can increase the propagation paths between the APs and STAs for which channel estimation can be performed.

[0309] In addition, regarding the format of the MAP Trigger, for example, the format of the existing basic trigger can be followed.

[0310] In method 3, for example, a new "MAP Trigger (Sounding)" corresponding to the MAP trigger requesting NDPA transmission is added to the trigger types. Furthermore, the trigger types may also include the precoded UL signal trigger of implementation 1. Figure 35 This shows an example of the trigger type in the case of a newly added MAP trigger (probe).

[0311] also, Figure 36 This shows an example of the overall format of a trigger frame related to MAP triggering (probing). In Figure 36 In the case of MAP triggering (probing), the broadcast address is set in the RA (Receiver Address) field.

[0312] Figure 37 This shows an example of a common information field for MAP triggering (probing). Figure 38 This shows an example of a user information field triggered by a MAP probe. Additionally, Figure 37 and Figure 38 The formats shown illustrate examples of formats that follow the basic trigger.

[0313] When triggered by a MAP (probe), add a "Precoder Calculation Indication" subfield (e.g., 1 bit) to the General Information field. Figure 37 In this example, B53 (reserved in the existing format) is set as the precoder calculation indicator subfield. The precoder calculation indicator subfield notifies the shared AP whether to send an instruction to STA200 to generate the precoder's NDPA.

[0314] Furthermore, the aforementioned instruction to generate the pre-encoder's NDPA refers to method 2 (e.g., Figure 20 and Figure 21 In NDPA, the value of the precoder subfield is set to 1.

[0315] Figure 39 This illustrates an example of how the precoder calculates the correspondence between the values ​​of an indicator subfield and the content. In Figure 39 In the configuration, if the value of the precoder calculation indicator subfield is 1, the shared AP is requested to send an indication to STA200 to generate the precoder's NDPA; if the value of the precoder calculation indicator subfield is 0, the shared AP is not requested to send an indication to STA200 to generate the precoder's NDPA. Furthermore, it is possible to... Figure 39When the pre-encoder calculates that the value of the indicator subfield is 0, the steps of the proposed Joint NDP sounding (see, for example, non-patent documents 7 and 8) are implemented.

[0316] In addition, when the MAP triggers (probes), the trigger-related general information fields can be omitted.

[0317] In addition, in the user information field triggered (probeed) by MAP (e.g., Figure 38 In the AID12 subfield, set the AID (Association ID (Identification (Identifier))) of the shared AP. Alternatively, you can choose not to use the trigger-related user information.

[0318] <map ndpa的发送>

[0319] The sharing AP and the shared AP (e.g., MAP control unit 114) instruct the data generation unit 112 to generate MAP NDPA based on information related to MAP triggering.

[0320] MAP NDPA can be as follows Figure 40 The format extends the existing NDPA frame as shown. Figure 40 In the STA information field, the value of the "Generate Precoder" subfield is set to 1, instructing STA200 to generate a precoder. Alternatively, if the value of the "Generate Precoder" subfield is set to 0, no instruction to STA200 to generate a precoder is given.

[0321] This is possible if the precoder subfield is 1. Figure 40 B21 to B24, as shown, notify each STA200 of the number of UL signals sent by the STA200 (the same method as in Method 2).

[0322] also, Figure 40 Fields B25 to B30 are set as the "Joint NDP sounding AP ID" subfield, used to notify the identifier of the AP100a sending the MAP NDP. This identifier can be an identifier (different from the MAC address) determined by the AP managing the MAP coordination (the coordinating AP) during the negotiation of the MAP coordination set.

[0323] Furthermore, by assigning multiple STA information fields to a single STA200, information related to multiple AP100a (e.g., all AP100a) that send MAP NDP can be communicated.

[0324] It should be noted that in the multiple STA information fields assigned to a STA200, the number of UL signals (e.g., B21 to B24) can all be the same value. Alternatively, the number of UL signals can be set in the first STA information field among the multiple STA information fields, and the other STA information fields (B21 to B24) can be set as reserved.

[0325] like Figure 34 As shown, the sharing AP and the AP being shared send the generated MAP NDPA to the STA200 (STA1 in AP1 and STA2 in AP2) connected to the AP at the same time.

[0326] The STA200 demodulates and decodes the received MAP NDPA, and obtains the destination AP and stream number of the UL signal (pre-encoded NDP) based on the joint NDP probe AP ID and stream number (e.g., B21 to B24) contained in the data signal.

[0327] <map ndp的发送>

[0328] The shared AP and the shared-by AP (e.g., the preamble generation unit 111) generate a MAP NDP after transmitting a MAP NDPA.

[0329] Here, the number of rows and the starting row number of the orthogonal code (P matrix) applied by the shared-by AP to the MAP NDP are values notified by the "number of spatial streams" subfield and the "starting spatial stream" subfield triggered by the MAP (e.g., Figure 38 ).

[0330] For example, the shared AP notifies the shared-by AP of the number of rows (number of spatial streams) and the starting row number (starting spatial stream) of the orthogonal code applied to the MAP NDP. For example, when the shared AP and the shared-by AP each use 4 streams to transmit the MAP NDP, the shared AP notifies the shared-by AP of the number of spatial streams = 3 (4 streams) and the starting spatial stream = 4 through the MAP trigger. For example, the following is notified: the shared AP uses 4 rows with indices 0 to 3, and the shared-by AP uses 4 rows with indices 4 to 7.

[0331] As Figure 34 shown, the shared AP and the shared-by AP transmit the generated MAP NDP at the same time and the same frequency.

[0332] <STA's precoder generation>

[0333] When STA200 receives the MAP NDP, it demodulates the preamble signal included in the MAP NDP, performs channel estimation, and generates a precoder. For example, STA200 (e.g., the channel estimation unit 204) can estimate the DL channel for each AP100a based on the MAP NDP and assume reciprocity to estimate the UL channel. For example, STA200 (e.g., the precoder generation unit 207) generates a precoder based on the number of streams notified by the MAP NDPA.

[0334] Here, the generated precoder forms a beam for each AP100a that transmitted the MAP NDP.

[0335] <AP's precoded UL signal trigger transmission>

[0336] Each AP100a (e.g., the data generation unit 112) generates a precoded UL signal trigger after transmitting the MAP NDP. For example, regarding the user information field in the precoded UL signal trigger of method 2, the format can be extended as Figure 41 shown. For example, in Figure 41 , a new "Joint Sounding" subfield is added. Figure 42 An example of the correspondence between the values and contents of the joint detection subfield is shown.

[0337] As Figure 34 shown, the shared AP and the shared-by AP trigger the transmission of the generated precoded UL signal to STA200.

[0338]

[0339] When STA200 receives the precoded UL signal trigger, it separates the preamble signal and the data signal of the precoded UL signal trigger and demodulates them separately. In addition, STA200 (e.g., data decoding unit 206) obtains the control information included in the precoded UL signal trigger.

[0340] STA200 (e.g., reference signal generation unit 210 and control signal generation unit 212) generates the preamble signal included in the UL signal.

[0341] At this time, STA200 sets the AP notified by the joint NDP detection AP ID of MAP NDPA as the destination. For example, in Figure 42 the example, when the value of the joint detection subfield is 1, STA200 determines that the NDP received by STA200 corresponds to MAP NDP and determines the destination of the UL signal as the shared AP and the shared-by AP. In addition, in Figure 42 the example, when the value of the joint detection subfield is 0, STA200 determines that the NDP received by STA200 does not correspond to MAP NDP and regards the trigger frame as the same precoded UL signal trigger as method 2 to determine the destination of the UL signal.

[0342] STA200 (e.g., precoding matrix multiplication unit 213) applies the generated precoder to the reference signal (and, in the case where the UL signal is a TB PPDU, to the data signal).

[0343] In the case of performing MAP coordination, as Figure 34 shown, STA200 transmits the generated UL signal to the shared AP and the shared-by AP.

[0344] <Quality Information Sharing between APs>

[0345] Each AP100a performs channel estimation and reception quality estimation based on the preamble signal included in the received UL signal.

[0346] The shared AP (e.g., preamble generation unit 111 and data generation unit 112) generates a data signal (e.g., MU PPDU) for transmitting quality information estimated by the shared AP (e.g., reception quality information) to the sharing AP. Figure 34 As shown, the shared AP sends the generated data signal to the sharing AP. Thus, the reception quality between each AP110a and STA200 is shared among multiple AP110a.

[0347] <Stream numbering pattern determination and UL data transmission>

[0348] After receiving data signals from the shared AP, the shared AP demodulates and decodes them, and saves the reception quality information.

[0349] The shared AP (e.g., the precoder selection unit 107) determines the stream numbering mode of each STA200 based on the received reception quality information of the shared AP and the reception quality information estimated by the shared AP from the UL signal.

[0350] For example, such as Figure 34 As shown, the shared AP (e.g., data generation unit 112) uses the basic triggering method 1 to notify each STA 200 to send UL data. In Figure 34 In the example, AP1 (the sharing AP) notifies STA1, which is connected to AP1, of the flow number so that it does not beam toward AP2 (the shared AP). Additionally, AP1 notifies STA2, which is connected to AP2, of the flow number so that it does not beam toward AP1 but rather toward AP2.

[0351] Upon receiving a basic trigger, the STA200, for example, similar to method 1, applies a pre-encoder to the UL data signal based on the acquired stream numbering pattern and sends the UL data to its respective destination, AP100a.

[0352] The above describes an operational example of AP100a and STA200 in this embodiment.

[0353] In this implementation (method 3), multiple AP100a coordinate to perform NDP probing, thereby enabling UL precoder selection that takes into account interference with Overlapping Basic Service Set (OBSS) APs, thus expecting an increase in system throughput.

[0354] (Transformation)

[0355] The following describes a method for extending the above embodiments (e.g., methods 1 to 3) to transmit UL signals and UL data multiplexed by multiple STA200s to an AP (AP100 or AP100a) via UL MU-MIMO.

[0356] When applying the MU condition, the methods in methods 1-3 can be simply extended. Here, the starting indices are made different so that the space flows allocated to each STA200 are orthogonal. For this purpose, for example, in the user information field of the basic trigger in method 1 (e.g., Figure 15 In this system, by setting the starting spatial flow subfield (e.g., B26 to B29) for each STA200, code division multiplexing between MUs based on orthogonal codes (e.g., P matrix) can be achieved.

[0357] As an example, this describes a scenario where, for an AP (AP100 or AP100a), STA1 and STA2 each send UL signals using three streams. The AP notifies STA1 of stream numbers 1 and 3, and STA2 of stream numbers 1, 2, and 3.

[0358] In this case, since STA1 can be used starting from the first row of the P matrix, the value of the initial spatial stream for STA1 is set to 0 (corresponding to the first row), and the two streams numbered 1 and 3 are notified to send. Since a P matrix with 2 rows (equivalent to 2 streams) is used for STA1, the value of the initial spatial stream for STA2 is 2 (e.g., corresponding to the third row), and the three streams are notified to send. Here, for example, if STA3 is also multiplexed, since a P matrix with 5 rows (equivalent to 5 streams) is used for STA1 and STA2, the value of the initial spatial stream for STA3 is 5 (e.g., corresponding to the sixth row).

[0359] In methods 1-3, the MU is multiplexed by multiple STA200s, so the AP can take into account the reception quality of the non-orthogonal precoders between STA200s, thereby enabling the selection of MU pairings with good reception quality in the AP (e.g., combination and number of STA200s).

[0360] The above describes various embodiments of this disclosure.

[0361] Furthermore, while the above embodiments describe communication between AP-STAs, these embodiments are not limited to communication between AP-STAs; for example, they can also be applied to communication between APs in a MAP.

[0362] Furthermore, in the above embodiments, the "control signal" that includes the stream numbering pattern can be, for example, a trigger frame, or other signals different from the trigger frame.

[0363] Furthermore, in the above embodiments, the time corresponding to "recent" (e.g., denoted as X) can be pre-defined in the standard or notified to STA200 from AP (e.g., AP100 or AP100a) via a beacon. For example, if time X has elapsed since the transmission of the UL signal, STA200 may transmit the UL data without precoding it. Additionally, for example, an identifier for the UL signal may be transmitted from AP to correspond the stream numbering pattern to a UL signal other than the most recent UL signal. The identifier for the UL signal may be a temporarily issued identifier (e.g., also called a token) for each UL signal, or it may be an identifier assigned separately to each precoder. In the case where the identifier is assigned separately to each precoder, the same identifier can be assigned to multiple UL signals using the same precoder.

[0364] The identifier of the aforementioned UL signal can be included in the control signal (e.g., trigger frame) from the AP100. For example, for Figure 15 The user information field of the basic trigger shown can use bits from existing subfields (e.g., 2 bits from the Preferred AC subfield in the trigger-related user information, or 1 bit each from the RU Allocation subfield and the PS160 subfield) as subfields that serve as identifiers for notifying UL signals.

[0365] Furthermore, the AP100 can also notify the STA200 by including the identifier of the aforementioned UL signal in the trigger frame of the new trigger type. For example, it can be as follows: Figure 43 As shown, a new trigger type, "Stream NumberIndication Trigger," has been added as a control signal that includes an identifier for the UL signal.

[0366] Here, the format for the stream number indicator trigger can follow the existing basic trigger format. Figure 44 This shows an example of a generic information field triggered by a flow number indicator. Figure 45 This shows an example of a user information field triggered by a flow number indicator. Additionally, Figure 44 and Figure 45 The formats shown illustrate examples of formats that follow the basic trigger.

[0367] Here, about Figure 45 The user information field shown, the stream number pattern subfield uses 4 bits to notify implementation method 1 and Figures 10-13 , Figure 15 The subfields of the stream numbering pattern shown. In addition, Figure 45 The UL SignalID subfield shown is a subfield that identifies the UL signal (the UL signal sent before the flow number indication sent by AP100) using an 8-bit notification that corresponds to the flow number pattern. Furthermore, the number of bits for both the flow number pattern subfield and the UL SignalID subfield is only one example; other numbers of bits are also possible.

[0368] Furthermore, in the above embodiments, the UL transmission operation in the absence of a basic trigger (when STA200 does not receive a trigger frame) can be any of the following.

[0369] (A)STA200 transmits UL data based on the most recent instructions from AP100 after precoding.

[0370] (B)STA200 sends UL data without precoding.

[0371] (C) The AP (AP100 or AP100a) decides (or selects) one of operations (A) and (B) and notifies the STA200 via a beacon or the like.

[0372] Furthermore, in the above embodiments, the operation of STA supporting existing standards can be any of the following.

[0373] (A) The STA does not generate a precoder. The STA provides feedback on the NDP from the AP. The STA treats the NDPA of Method 2 and Method 3 as the existing standard NDPA.

[0374] (B) Regarding operation (A), the STA does not send feedback until it receives a BFRP (BF Report Poll) from the AP.

[0375] (C) STA does not generate a pre-encoder and does not send UL signals.

[0376] Furthermore, in the above embodiments, the field (or subfield) used for notifying control information is only one example; other fields or subfields may also be used. Additionally, the number of bits used for notifying control information in each field or subfield is only one example; other numbers of bits may also be used. Moreover, in the name of the field or subfield, the term "UHR" may be omitted, or other terms indicating versions of other standards or terminal capabilities may be used instead.

[0377] Furthermore, the signal format described in the above embodiments is only one example. It may also be another structure in which at least one of the following has been added or deleted: other fields have been added or deleted: other subfields ...

[0378] Furthermore, although the above embodiments illustrate a case based on the format specified in IEEE 802.11 as an example, the format of an embodiment of this disclosure is not limited to the IEEE 802.11 format.

[0379] Furthermore, in the above embodiment, the value, size (number of bits) of the control information notified to STA200, and the content corresponding to the value of the control information are only one example, and may be other values, sizes, and contents.

[0380] This disclosure can be implemented in software, hardware, or software in cooperation with hardware. The functional blocks used in the above embodiments are implemented partially or wholly as LSIs (Large Scale Integration), and the processes described in the above embodiments can also be controlled partially or wholly by a single LSI or a combination of LSIs. An LSI can be composed of individual chips, or it can be composed of a single chip containing some or all of the functional blocks. An LSI may also include data input and output. Depending on the degree of integration, an LSI may also be referred to as an "IC (Integrated Circuit)," a "System LSI," a "Super LSI," or an "Ultra LSI."

[0381] The method of integrating LSIs is not limited to LSIs; it can also be implemented using dedicated circuits, general-purpose processors, or special-purpose processors. Alternatively, LSIs can be used to fabricate programmable FPGAs (Field Programmable Gate Arrays), or reconfigurable processors that allow for reconfiguration of the connections or settings of the circuit blocks within the LSI. This disclosure can also be implemented for digital or analog processing.

[0382] Furthermore, if advancements in semiconductor technology or the emergence of other derivative technologies lead to integrated circuit technologies that can replace LSIs, these technologies could also be used to integrate functional blocks. There are also possibilities for applications such as biotechnology.

[0383] This disclosure can be implemented in all kinds of devices, apparatuses, and systems with communication capabilities (collectively referred to as "communication devices"). A communication device may also include a wireless transceiver and processing / control circuitry. The wireless transceiver may also include a receiving unit and a transmitting unit, or perform the functions of these units. 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 similar devices. Non-limiting examples of communication devices include: telephones (mobile phones, smartphones, etc.), tablet computers, personal computers (PCs) (laptops, desktops, laptops, etc.), cameras (digital cameras, digital camcorders, etc.), digital players (digital audio / video players, etc.), wearable devices (wearable cameras, smartwatches, tracking devices, etc.), game consoles, e-book readers, remote health / telemedicine (remote healthcare / medical prescription) devices, vehicles or transportation vehicles with communication capabilities (cars, airplanes, ships, etc.), and combinations of the various devices described above.

[0384] Communication devices are not limited to portable or movable devices, but also include all kinds of devices, equipment, and systems that cannot be carried or fixed. Examples 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.

[0385] In addition to data communication via cellular systems, wireless LAN (Local Area Network) systems, and communication satellite systems, communication also includes data communication via a combination of these systems.

[0386] In addition, the communication device also includes devices such as controllers or sensors that are connected or linked to a communication device performing the communication functions described in this disclosure. For example, it includes a controller or sensor that generates control signals or data signals used by the communication device to perform the communication functions of the communication device.

[0387] In addition, the communication device includes infrastructure equipment that communicates with or controls the various devices described above (not limited to these), such as base stations, access points, and all other devices, equipment, and systems.

[0388] An access point according to one embodiment of this disclosure includes: a transmitting circuit that transmits information about a pattern of a stream corresponding to an uplink signal from a terminal to the terminal; and a receiving circuit that receives a signal pre-coded based on the pattern.

[0389] In one embodiment of this disclosure, the mode includes at least one of a plurality of streams applied to the uplink signal.

[0390] In one embodiment of this disclosure, the pattern includes non-contiguous numbers among the numberings assigned to the plurality of streams.

[0391] In one embodiment of this disclosure, the uplink signal is an empty data packet (NDP) sent using the plurality of streams, or a signal containing data sent using the plurality of streams.

[0392] In one embodiment of this disclosure, the uplink signal is a signal received by the access point from the terminal within a specified time.

[0393] In one embodiment of this disclosure, the uplink signal is the latest signal received by the access point from the signals received by the terminal.

[0394] In one embodiment of this disclosure, the transmitting circuit sends to the terminal a signal indicating the generation of a precoder and a training signal, the mode being determined using the uplink signal to which the precoder is applied, the precoder being generated in the terminal based on a channel estimate estimated using the training signal.

[0395] In one embodiment of this disclosure, the transmitting circuit sends a control signal to the terminal indicating the transmission of the uplink signal.

[0396] In one embodiment of this disclosure, the mode is determined based on channel estimates between the terminal and each of the multiple access points.

[0397] One embodiment of the present disclosure includes a terminal comprising: a receiving circuit for receiving information about a pattern of a stream corresponding to an uplink signal from the terminal; and a transmitting circuit for transmitting a signal pre-coded based on the pattern.

[0398] In a communication method according to an embodiment of this disclosure, an access point performs the following steps: sending information about a pattern of a stream corresponding to an uplink signal from a terminal to the terminal; and receiving a signal pre-coded based on the pattern.

[0399] In a communication method according to an embodiment of this disclosure, a terminal performs the following steps: receiving information about a pattern of a stream corresponding to an uplink signal from the terminal; and sending a signal pre-coded based on the pattern.

[0400] The entire contents of the specification, drawings and abstract of the specification contained in Japanese Patent Application No. 2023-191792, filed on November 9, 2023, are incorporated herein by reference.

[0401] Industrial applicability

[0402] One embodiment of this disclosure is useful for wireless communication systems.

[0403] Explanation of reference numerals in the attached figures

[0404] 100, 100a AP

[0405] Wireless transceiver units 101 and 201

[0406] 102, 202 Demultiplexing Section

[0407] 103 Orthogonal Separation Part

[0408] 104, 203 Preamble Demodulation Unit

[0409] Channel estimation units 105 and 204

[0410] 106 Quality Estimation Department

[0411] 107 Pre-encoder selection section

[0412] Data Demodulation Departments 108 and 205

[0413] Data Decoding Departments 109 and 206

[0414] 110, 208 Stream Numbering Pattern Preservation Department

[0415] 111 Preamble Generation Unit

[0416] Data Generation Departments 112 and 211

[0417] 113, 216 Reuse Section

[0418] 114 MAP Control Department

[0419] 200 STA

[0420] 207 Pre-encoder generation unit

[0421] 209 Pre-encoder holding section

[0422] 210 Reference Signal Generation Unit

[0423] 212 Control Signal Generation Unit

[0424] 213 Precoding matrix multiplication part

[0425] 214 Modulation Section

[0426] 215 Orthogonalization section< / map> < / map>

Claims

1. An access point, characterized in that, have: The transmitting circuit transmits information about the pattern of the stream corresponding to the uplink signal from the terminal to the terminal; and A receiving circuit receives a signal pre-coded based on the stated pattern.

2. The access point as described in claim 1, wherein, The mode includes at least one of a plurality of streams applied to the uplink signal.

3. The access point as described in claim 2, wherein, The pattern includes non-contiguous numbers among the numbers assigned to the plurality of streams.

4. The access point as described in claim 2, wherein, The uplink signal is an empty data packet (NDP) sent using the multiple streams, or a signal containing data sent using the multiple streams.

5. The access point as described in claim 1, wherein, The uplink signal is the signal received by the access point from the terminal within a specified time.

6. The access point as described in claim 1, wherein, The uplink signal is the latest signal received by the access point from the signals received by the terminal.

7. The access point as described in claim 1, wherein, The transmitting circuit sends a signal indicating the generation of the pre-encoder and a training signal to the terminal. The mode is determined using the uplink signal to which the precoder is applied, the precoder being generated in the terminal based on a channel estimate estimated using the training signal.

8. The access point as described in claim 7, wherein, The transmitting circuit sends a control signal to the terminal, instructing the transmission of the uplink signal.

9. The access point as described in claim 1, wherein, The mode is determined based on the channel estimates between each of the multiple access points and the terminal.

10. A terminal, characterized in that, have: A receiving circuit that receives information about the pattern of the stream corresponding to the uplink signal from the terminal; and The transmitting circuit transmits a signal pre-coded based on the stated pattern.

11. A communication method, characterized in that, The access point performs the following steps: Information about the pattern of the stream corresponding to the uplink signal from the terminal is sent to the terminal; and Receive the signal pre-coded based on the pattern.

12. A communication method, characterized in that, The terminal performs the following steps: Receive information about the pattern of the stream corresponding to the uplink signal from the terminal; and Send a signal that has been precoded based on the pattern.

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