Obtaining channel information for multi-access point coordination

Abstract

A method performed by a sharing access point (AP) for implementing coordinated spatial multiplexing with a shared AP. The sharing AP belongs to a first basic service set (BSS) and the shared AP belongs to a second BSS. The method includes sending a multi-AP (M-AP) trigger frame to the shared AP, sending a first measurement frame to a first station (STA) belonging to the first BSS, wherein the shared AP sends a second measurement frame to a second STA belonging to the second BSS in response to receiving the M-AP trigger frame, sending an interference measurement feedback request frame to the first STA, and receiving an interference measurement feedback frame from the first STA in response to the interference measurement feedback request frame, the interference measurement feedback frame including an indication of a first downlink interference amount at the first STA caused by the second measurement frame.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 619,691, filed January 10, 2024, entitled “Interference measurement of Coordinated Spatial Reuse (C-SR) with Distributed Tone RU (dRU) beyond IEEE 802.11be”, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This disclosure generally relates to wireless communications, and more specifically, to obtaining channel information for multi-access point coordination. Background Technology

[0004] The Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard is a set of standards for enabling wireless local area network (WLAN) communication across a variety of frequencies, including but not limited to the 2.4 GHz, 5 GHz, 6 GHz, and 60 GHz bands. These standards define the protocols that enable Wi-Fi devices to communicate with each other. The IEEE 802.11 family of standards has evolved over time to accommodate higher data rates, improved security, and better performance in different environments. Some of the most widely used standards include 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac, and 802.11ax (also known as “Wi-Fi 6”). These standards specify modulation techniques, channel bandwidth, and other technical aspects to facilitate interoperability between devices from different manufacturers. IEEE 802.11 has played a significant role in the widespread adoption of wireless networks in homes, offices, and public places, allowing users to connect their devices to the internet and to each other without a wired connection.

[0005] IEEE 802.11be, also known as "Wi-Fi 7," is the next generation of the IEEE 802.11 family of standards for wireless local area networks. Currently under development, 802.11be aims to significantly improve upon its predecessor, 802.11ax / Wi-Fi 6, by providing higher data rates, lower latency, and greater reliability. The standard is expected to leverage advanced technologies such as Multi-Link Operation (MLO), which allows devices to use multiple frequency bands and channels simultaneously to enhance performance and reliability. Furthermore, 802.11be will introduce 4096-QAM (Quadrature Amplitude Modulation), achieving higher data rates by encoding more bits per symbol. The standard will also feature improved Media Access Control (MAC) efficiency, enhanced energy efficiency, and better support for high-density environments. With these advancements, 802.11be is expected to deliver a theoretical maximum data rate of up to 46 gigabits per second (Gbps), making it suitable for bandwidth-intensive applications such as virtual and augmented reality, 8K video streaming, and high-performance gaming. The IEEE 802.11be standard is expected to be finalized by the end of 2024, paving the way for next-generation Wi-Fi devices and networks.

[0006] Coordinated Space Reuse (C-SR) and Distributed Spectrum Resource Units (dRUs) are techniques that help improve the spectrum efficiency of wireless networks. C-SR can help improve spectrum efficiency by allowing multiple devices to transmit simultaneously in the same frequency band without causing significant interference. During C-SR, two APs can simultaneously send downlink (DL) Physical Layer Protocol Data Units (PPDUs) to a Station (STA) or request simultaneous uplink (UL) PPDUs from the STA. To successfully implement C-SR without interference between different Basic Service Sets (BSSs), an "interference measurement phase" can initially be performed to determine the amount of interference between different BSSs. The interference measurement phase can include a downlink interference measurement phase and an uplink interference measurement phase. The transmit power used for DL ​​transmission and / or UL transmission during C-SR can be determined based on the amount of interference between different BSSs. The goal of determining the transmit power is to reduce the amount of interference between different BSSs to allow simultaneous transmission.

[0007] A resource unit (dRU) can be a collection of subcarriers (non-contiguous subcarriers) distributed across the entire spectrum. dRUs can help overcome power spectral density (PSD) limitations. Various power modes are defined in the 6 GHz band, such as standard power (SP) mode, very low power (VLP) mode, and low power indoor (LPI) mode. PSD limitations are very stringent, especially in VLP and LPI modes in the 6 GHz band, particularly for non-AP STAs. For example, the PSD limit for non-AP STAs in LPI mode is -1 dBM / MHz. Therefore, due to the strict PSD limitations, using a large number of resource unit (RU) subcarriers within a limited bandwidth reduces transmit power. Attached Figure Description

[0008] This disclosure will be more fully understood from the detailed description and the accompanying drawings depicting various embodiments of this disclosure provided below. However, these drawings should not be construed as limiting this disclosure to the specific embodiments shown; they are for explanation and understanding only.

[0009] Figure 1 Examples of wireless local area networks (WLANs) with a basic service set (BSS) that include multiple wireless devices are shown according to some embodiments of the present disclosure.

[0010] Figure 2 This is a schematic diagram of a wireless device according to some embodiments of the present disclosure.

[0011] Figure 3A Components of a wireless device configured to transmit data according to some embodiments of the present disclosure are shown.

[0012] Figure 3B Components of a wireless device configured to receive data according to some embodiments of the present disclosure are shown.

[0013] Figure 4 Inter-frame spacing (IFS) relationships according to some embodiments of this disclosure are shown.

[0014] Figure 5 A frame transmission process based on Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA) according to some embodiments of this disclosure is illustrated.

[0015] Figure 6 The highest physical layer (PHY) rate of the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard is shown according to some embodiments of this disclosure.

[0016] Figure 7 Detailed descriptions of the fields in an Extremely High Throughput (EHT) Physical Protocol Data Unit (PPDU) frame according to some embodiments of this disclosure are provided, including their purpose and characteristics.

[0017] Figure 8 Examples of multi-user (MU) transport in orthogonal frequency division multiple access (OFDMA) according to some embodiments of the present disclosure are shown.

[0018] Figure 9 An example is shown whereby an access point according to some embodiments of the present disclosure sends a trigger frame to multiple associated sites and receives an uplink orthogonal frequency division multiple access trigger base physical protocol data unit (UL OFDMA TB PPDU) in response.

[0019] Figure 10 This is a schematic diagram of two main stages of the Coordinated Space Reuse (C-SR) process according to some embodiments.

[0020] Figure 11 This is a communication sequence diagram of the interference measurement phase (for option 1) according to some embodiments.

[0021] Figure 12 This is a communication sequence diagram of the interference measurement phase (for option 2) according to some embodiments.

[0022] Figure 13 This is a schematic diagram illustrating uplink interference in a wireless network during C-SR according to some embodiments.

[0023] Figure 14 This is a communication sequence diagram illustrating an interference measurement phase that allows the determination of uplink interference levels in a dRU, according to some embodiments.

[0024] Figure 15 This is a flowchart of a method for implementing C-SR in the downlink direction according to some embodiments.

[0025] Figure 16 This is a flowchart of a method for implementing C-SR in the uplink direction according to some embodiments.

[0026] Figure 17 This is a flowchart of a method for providing downlink interference measurement feedback information according to some embodiments.

[0027] Figure 18 This is a flowchart of a method for obtaining channel information according to some embodiments.

[0028] Figure 19 This is a flowchart of a method for providing channel information according to some embodiments. Detailed Implementation

[0029] This disclosure generally relates to wireless communications, and more specifically, to obtaining channel information for multi-access point (M-AP) coordination.

[0030] Coordinated Spatial Reuse (C-SR) is a multi-AP coordination scheme that helps improve spectrum efficiency. For successful C-SR implementation, controlling the transmit power of participating devices to reduce interference is crucial. This paper describes techniques that allow a Station (STA) to provide information about the amount of downlink interference at its location to an Access Point (AP), enabling the AP to determine the appropriate transmit power for multiple APs to apply to downlink transmissions to the STA for C-SR. Furthermore, this paper describes techniques that allow an AP to determine the amount of uplink interference at its location, enabling the AP to determine the appropriate transmit power for STAs to apply to uplink transmissions to the AP for C-SR. In one embodiment, the STA provides information about the amount of downlink interference at its location to the AP in a frame referred to herein as an interference measurement feedback frame. In another embodiment, the STA sends the interference measurement feedback frame to the AP in a Distributed Spectrum Resource Unit (dRU), allowing the AP to determine the amount of uplink interference at its location relative to that dRU without additional overhead (e.g., without sending / swapping additional frames).

[0031] According to some embodiments, a shared AP belonging to a first basic service set (BSS) can send a multi-AP trigger frame to a shared AP belonging to a second BSS. After sending the multi-AP trigger frame, the shared AP can send a first measurement frame to a first STA belonging to the first BSS. In response to receiving the M-AP trigger frame from the shared AP, the shared AP can send a second measurement frame to a second STA belonging to the second BSS. The sending of the first measurement frame by the shared AP and the sending of the second measurement frame by the shared AP can occur simultaneously. The first STA can determine a first amount of interference caused by the second BSS at the first STA based on the received signal strength of the first and second measurement frames. Similarly, the second STA can determine a second amount of interference caused by the first BSS at the second STA based on the received signal strength of the first and second measurement frames. The shared AP can send an interference measurement feedback request frame to both the first and second STAs, requesting interference measurements from both STAs. In response to receiving the interference measurement feedback request frame, the first STA can send a first interference measurement feedback frame to the shared AP, which includes an indication of the amount of downlink interference caused by the second BSS at the first STA. Similarly, in response to receiving an interference measurement feedback request frame, the second STA can send a second interference measurement feedback frame to the shared AP, the second interference measurement feedback frame including an indication of the amount of downlink interference caused by the first BSS at the second STA.

[0032] The sharing AP can determine the first downlink transmit power to be used by the sharing AP and the second downlink transmit power to be used by the shared AP based on the first downlink interference level and the second downlink interference level. The sharing AP can send a power control information frame to the shared AP, which includes an indication of the second downlink transmit power. The sharing AP can then send a first downlink frame to a first STA using the first downlink transmit power. The shared AP can send a second downlink frame to a second STA using the second downlink transmit power indicated in the power control information frame. The sharing AP sending the first downlink frame and the shared AP sending the second downlink frame can occur simultaneously to achieve C-SR in the downlink direction.

[0033] In this embodiment, the first STA and the second STA transmit a first interference measurement feedback frame and a second interference measurement feedback frame to the shared AP from within the dRU, respectively. The shared AP can determine the amount of first uplink interference caused by the second BSS at the shared AP and the amount of second uplink interference caused by the first BSS at the shared AP based on the received signal strength of the first interference measurement feedback frame received from the first STA and the second interference measurement feedback frame received from the second STA. Transmitting the interference measurement feedback frame in the dRU enables the shared AP to determine the amount of uplink interference at the shared AP for that dRU and / or the amount of uplink interference at the shared AP for that dRU without additional overhead (e.g., without sending / swapping additional frames).

[0034] The shared AP can determine a first uplink transmit power to be used by the first STA and a second uplink transmit power to be used by the second STA based on a first uplink interference level and a second uplink interference level. The shared AP can include an indication of the second uplink transmit power in its power control information frames sent to the shared AP (therefore, the power control information frames can include indications of both the second downlink transmit power and the second uplink transmit power). The shared AP can send a first trigger frame to the first STA using the first downlink transmit power to request uplink transmission from the first STA, wherein the first trigger frame includes an indication of the first uplink transmit power. The shared AP can simultaneously send a second trigger frame to the second STA using the second downlink transmit power to request uplink transmission from the second STA, wherein the second trigger frame includes an indication of the second uplink transmit power. The sending of the first trigger frame by the shared AP and the sending of the second trigger frame by the shared AP can occur simultaneously to implement C-SR in the downlink direction. In response to receiving the first trigger frame, the first STA can send a first uplink frame to the shared AP in the dRU using the first uplink transmit power. Furthermore, in response to receiving the second trigger frame, the second STA can use the second uplink transmit power to send the second uplink frame to the shared AP in the dRU. The first STA sending the first uplink frame and the second STA sending the second uplink frame can occur simultaneously to achieve C-SR in the uplink direction.

[0035] For illustrative purposes, this document describes various embodiments within the context of wireless networks based on the IEEE 802.11 standard and using its terminology and concepts. Those skilled in the art will understand that the embodiments disclosed herein can be modified / adapted for use in other types of wireless networks.

[0036] In the following detailed description, certain embodiments of the invention are shown and described by way of illustration only. As those skilled in the art will recognize, the described embodiments can be modified in different ways without departing from the spirit or scope of the invention. Therefore, the drawings and descriptions should be considered illustrative in nature and not restrictive. Throughout the specification, the same reference numerals denote the same elements.

[0037] Figure 1 A wireless local area network (WLAN) 100 with a basic service set (BSS) 102 is illustrated, which includes multiple wireless devices 104 (sometimes referred to as WLAN devices 104). Each wireless device 104 may include a media access control (MAC) layer and a physical (PHY) layer according to IEEE (Institute of Electrical and Electronics Engineers) standard 802.11 (including one or more revisions, such as 802.11a / b / g / n / p / ac / ax / bd / be)). In one embodiment, the MAC layer of wireless device 104 may initiate the transmission of a frame to another wireless device 104 by passing a PHY-TXSTART.request (TXVECTOR) to the PHY layer. The TXVECTOR provides parameters for generating and / or transmitting the corresponding frame. Similarly, the PHY layer of a receiving wireless device may generate an RXVECTOR, which includes parameters for receiving the frame and is passed to the MAC layer for processing.

[0038] Multiple wireless devices 104 may include wireless device 104A acting as an access point (sometimes referred to as an AP site or AP STA) and other wireless devices 104B1-104B4 acting as non-AP sites (sometimes referred to as non-AP STAs). Alternatively, in an ad-hoc network environment, all multiple wireless devices 104 may be non-AP STAs. Typically, AP STAs (e.g., wireless device 104A) and non-AP STAs (e.g., wireless devices 104B1-104B4) may be collectively referred to as STAs. However, for ease of description, unless the context otherwise requires, only non-AP STAs may be referred to as STAs. Although four non-AP STAs (e.g., wireless devices 104B1-104B4) are shown, WLAN 100 may include any number of non-AP STAs (e.g., one or more wireless devices 104B).

[0039] Figure 2 A schematic block diagram of a wireless device 104 according to an embodiment is shown. The wireless device 104 may be... Figure 1 The wireless device 104A (i.e., the AP of WLAN 100) or any of the wireless devices 104B1-104B4. Wireless device 104 includes a baseband processor 210, a radio frequency (RF) transceiver 240, an antenna unit 250, a storage device (e.g., a memory device) 232, one or more input interfaces 234, and one or more output interfaces 236. The baseband processor 210, storage device 232, input interface 234, output interface 236, and RF transceiver 240 can communicate with each other via bus 260.

[0040] The baseband processor 210 performs baseband signal processing and includes a MAC processor 212 and a PHY processor 222. The baseband processor 210 may utilize a memory 232, which may include a non-transitory computer / machine-readable medium storing software (e.g., computer / machine program instructions) and data.

[0041] In this embodiment, the MAC processor 212 includes a MAC software processing unit 214 and a MAC hardware processing unit 216. The MAC software processing unit 214 can implement a first plurality of functions of the MAC layer by executing MAC software, which may be included in software stored in the storage device 232. The MAC hardware processing unit 216 can implement a second plurality of functions of the MAC layer in dedicated hardware. However, the MAC processor 212 is not limited thereto. For example, depending on the implementation, the MAC processor 212 may be configured to execute the first plurality of and second plurality of functions entirely in software or entirely in hardware.

[0042] PHY processor 222 includes a transmit (TX) signal processing unit (SPU) 224 and a receive (RX) SPU 226. PHY processor 222 implements multiple functions of the PHY layer. Depending on the implementation, these functions can be executed in software, hardware, or a combination thereof.

[0043] The functions performed by the transmitting SPU 224 may include one or more of the following: forward error correction (FEC) coding, parsing a stream into one or more spatial streams, diversity coding of a spatial stream into multiple space-time streams, spatial mapping of space-time streams to a transmission chain, inverse Fourier transform (iFT) calculation, cyclic prefix (CP) insertion to create a guard interval (GI), etc. The functions performed by the receiving SPU 226 may include the inverse processes of the functions performed by the transmitting SPU 224, such as GI removal, Fourier transform calculation, etc.

[0044] RF transceiver 240 includes an RF transmitter 242 and an RF receiver 244. RF transceiver 240 is configured to transmit first information received from baseband processor 210 to WLAN 100 (e.g., to another WLAN device 104 of WLAN 100) and to provide second information received from WLAN 100 (e.g., from another WLAN device 104 of WLAN 100) to baseband processor 210.

[0045] Antenna element 250 includes one or more antennas. When using multiple-input multiple-output (MIMO) or multi-user MIMO (MU-MIMO), antenna element 250 may include multiple antennas. In an embodiment, the antennas in antenna element 250 may operate as a beamforming antenna array. In one embodiment, the antennas in antenna element 250 may be directional antennas, which may be fixed or steerable.

[0046] Input interface 234 receives information from the user, and output interface 236 outputs information to the user. Input interface 234 may include one or more of a keyboard, keypad, mouse, touchscreen, microphone, etc. Output interface 236 may include one or more of a display, touchscreen, speaker, etc.

[0047] As described herein, many of the functions of the WLAN device 104 can be implemented in hardware or software. Which functions are implemented in software and which are implemented in hardware will vary depending on the constraints imposed on the design. Constraints may include one or more of the following: design cost, manufacturing cost, time to market, power consumption, available semiconductor technology, etc.

[0048] As described herein, the functions of the components of WLAN device 104 can be implemented using a wide variety of electronic devices, circuits, firmware, software, and combinations thereof. Furthermore, WLAN device 104 may include other components such as application processors, storage interfaces, clock generator circuits, power supply circuits, etc., which have been omitted for the sake of brevity.

[0049] Figure 3A Components of a WLAN device 104 configured to transmit data according to one embodiment are shown, including a transmit (Tx) SPU (TxSP) 324, an RF transmitter 342, and an antenna 352. In the embodiment, the TxSP 324, RF transmitter 342, and antenna 352 correspond to... Figure 2 The antenna of the transmitting SPU 224, RF transmitter 242 and antenna unit 250.

[0050] The TxSP 324 includes an encoder 300, an interleaver 302, a mapper 304, an inverse Fourier transform (IFT) 306, and a guard interval (GI) inserter 308.

[0051] Encoder 300 receives and encodes input data. In an embodiment, encoder 300 includes a forward error correction (FEC) encoder. The FEC encoder may include a binary convolutional code (BCC) encoder and a subsequent punching device. The FEC encoder may include a low-density parity check (LDPC) encoder.

[0052] The TxSP 324 may also include a scrambler for scrambling the input data before the encoder 300 performs encoding to reduce the probability of long sequences of 0s or 1s. When the encoder 300 performs BCC encoding, the TxSP 324 may also include an encoder parser for demultiplexing the scrambled bits among multiple BCC encoders. If LDPC encoding is used in the encoder, the TxSP 324 may not need an encoder parser.

[0053] Interleaver 302 interleaves the bits of each stream output from encoder 300 to change the order of the bits. Interleaver 302 can apply interleaving only when encoder 300 performs BCC encoding; otherwise, it can output the streams output from encoder 300 without changing the bit order.

[0054] Mapper 304 maps the bit sequence output from interleaver 302 to constellation points. If encoder 300 performs LDPC encoding, mapper 304 can perform LDPC subcarrier mapping in addition to constellation mapping.

[0055] When the TxSP 324 performs MIMO or MU-MIMO transmission, it can include multiple interleavers 302 and multiple mappers 304 depending on the number of spatial streams (NSS) being transmitted. The TxSP 324 may also include a stream resolver for dividing the output of the encoder 300 into blocks and sending the blocks to different interleavers 302 or mappers 304. The TxSP 324 may also include a space-time block code (STBC) encoder for extending constellation points from the spatial streams to multiple space-time streams (NSTS), and a spatial mapper for mapping the space-time streams to the transmit chain. The spatial mapper can use direct mapping, spatial spreading, or beamforming.

[0056] IFT 306 converts the constellation point blocks output from mapper 304 (or, when performing MIMO or MU-MIMO, from the spatial mapper) into time-domain blocks (i.e., symbols) using inverse discrete Fourier transform (IDFT) or inverse fast Fourier transform (IFFT). If an STBC encoder and spatial mapper are used, IFT 306 can be provided for each transmit chain.

[0057] When the TxSP 324 performs MIMO or MU-MIMO transmissions, it can insert cyclic shift diversity (CSD) to prevent unintentional beamforming. The TxSP 324 can insert CSD before or after IFT 306. CSD can be specified by transmit chain or by space-time stream. Alternatively, CSD can be applied as part of a spatial mapper.

[0058] When the TxSP 324 performs MIMO or MU-MIMO transmissions, some blocks prior to the space mapper can be provided for each user.

[0059] The GI inserter 308 adds a GI before each symbol produced by the IFT 306. Each GI may include a cyclic prefix (CP), which corresponds to the repeating portion at the end of the symbol preceding that GI. After inserting the GI, the TxSP 324 may optionally perform windowing to smooth the edges of each symbol.

[0060] RF transmitter 342 converts symbols into RF signals and transmits the RF signals through antenna 352. When TxSP 324 performs MIMO or MU-MIMO transmission, a GI inserter 308 and an RF transmitter 342 can be provided for each transmission chain.

[0061] Figure 3B Components of a WLAN device 104 configured to receive data according to an embodiment are shown, including a receiver (Rx) SPU (RxSP) 326, an RF receiver 344, and an antenna 354. In the embodiment, the RxSP 326, RF receiver 344, and antenna 354 may correspond to... Figure 2 The antenna of the receiving SPU 226, RF receiver 244 and antenna unit 250.

[0062] The RxSP 326 includes a GI remover 318, a Fourier transform (FT) 316, a demapper 314, a deinterleaver 312, and a decoder 310.

[0063] RF receiver 344 receives RF signals via antenna 354 and converts the RF signals into symbols. GI remover 318 removes GIs from each symbol. When the received transmission is a MIMO or MU-MIMO transmission, RF receiver 344 and GI remover 318 can be provided for each receive chain.

[0064] FT 316 transforms each symbol (i.e., each time-domain block) into a frequency-domain block of constellation points using either the Discrete Fourier Transform (DFT) or the Fast Fourier Transform (FFT). FT 316 can be provided for each receiver chain.

[0065] When the received transmission is a MIMO or MU-MIMO transmission, the RxSP 326 may include a spatial demapper for converting the corresponding output of the FT 316 of the receive chain into constellation points of multiple space-time streams, and an STBC decoder for de-expanding the constellation points from the space-time streams into one or more spatial streams.

[0066] Demapper 314 demaps the constellation points output from the FT 316 or STBC decoder into a bitstream. If the received transmission is encoded using LDPC encoding, demapper 314 may also perform LDPC subcarrier demapping before performing constellation demapping.

[0067] Deinterleaver 312 deinterleaves the bits of each stream output from demapper 314. Deinterleaver 312 may perform deinterleaving only if the received transmission is encoded using BCC encoding; otherwise, it may output the streams from demapper 314 without performing deinterleaving.

[0068] When the received transmission is a MIMO or MU-MIMO transmission, the RxSP 326 can use multiple demappers 314 and multiple deinterleavers 312 corresponding to the number of spatial streams transmitted. In this case, the RxSP 326 may also include a stream inverse parser for combining the streams output from the deinterleavers 312.

[0069] Decoder 310 decodes the stream output from deinterleaver 312 or stream de-parser. In an embodiment, decoder 310 includes an FEC decoder. The FEC decoder may include a BCC decoder or an LDPC decoder.

[0070] RxSP 326 may also include a descrambler for descrambling the decoded data. When decoder 310 performs BCC decoding, RxSP 326 may also include an encoder inverse parser for multiplexing data decoded by multiple BCC decoders. When decoder 310 performs LDPC decoding, RxSP 326 may not use an encoder inverse parser.

[0071] Before transmission, wireless devices such as wireless device 104 use idle channel assessment (CCA) to evaluate the availability of the wireless medium. If the medium is occupied, CCA can determine that it is busy; if the medium is available, CCA can determine that it is idle.

[0072] The IEEE 802.11 PHY entities are based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). In the OFDM or OFDMA physical (PHY) layer, a STA (e.g., wireless device 104) is able to transmit and receive Physical Layer (PHY) Protocol Data Units (PPDUs) conforming to the mandatory PHY specification (also known as PLCP (Physical Layer Convergence Process) Protocol Data Units). The PHY specification defines a set of modulation and encoding / decoding schemes (MCS) and a maximum number of spatial streams. Some PHY entities define downlink (DL) and uplink (UL) multi-user (MU) transmissions with a maximum number of space-time streams (STS) per user and employing a maximum predetermined total number of STSs. The PHY entity can provide support for continuous channel widths of 10 MHz, 20 MHz, 40 MHz, 80 MHz, 160 MHz, 240 MHz, and 320 MHz, as well as non-contiguous channel widths of 80+80, 80+160 MHz, and 160+160 MHz. Each channel comprises multiple subcarriers, which may also be referred to as tones. The PHY entity can define signaling fields within the PPDU, represented as Traditional Signal (L-SIG), Signal A (SIG-A), and Signal B (SIG-B), through which necessary information about the attributes of the PHY Service Data Unit (PSDU) is conveyed. For completeness and simplicity, the following description refers to OFDM-based 802.11 technology. Unless otherwise specified, a site refers to a non-AP STA.

[0073] Figure 4 The inter-frame spacing (IFS) relationship is shown. Specifically, Figure 4 The Short IFS (SIFS), Point Coordination Function (PCF) IFS (PIFS), Distributed Coordination Function (DCF) IFS (DIFS), and Arbitration IFS (AIFS[i]) corresponding to Access Class (AC) 'i' are shown. Figure 4 The time slot duration and the data frame used to transmit data forwarded to higher layers are also shown. As illustrated, if the DIFS has expired during the medium idle period, the WLAN device 104 sends a data frame after performing a backoff.

[0074] Management frames can be used to exchange management information, which is not forwarded to higher layers. Subtypes of management frames include beacon frames, association request / response frames, probe request / response frames, and authentication request / response frames.

[0075] Control frames can be used to control access to the medium. Subtypes of control frames include Request to Send (RTS) frames, Clear to Send (CTS) frames, and Acknowledge (ACK) frames.

[0076] When the control frame is not a response frame to another frame, if the DIFS has passed during the medium idle period, the WLAN device 104 sends the control frame after performing backoff. When the control frame is a response frame to another frame, the WLAN device 104 sends the control frame after the SIFS has passed, without performing backoff or checking if the medium is idle.

[0077] If the AIFS (i.e., AIFS[AC]) of the associated Access Class (AC) has passed, the WLAN device 104 (i.e., the QoS STA) that supports Quality of Service (QoS) can send a frame after performing backoff. When sent by the QoS STA, any data frame, management frame, and control frame that is not a response frame can use the AIFS[AC] of the AC of the frame being sent.

[0078] When a WLAN device 104, ready to transmit a frame, detects that the medium is busy, the WLAN device 104 can perform a backoff procedure. The backoff procedure includes determining a random backoff time consisting of N backoff slots, where the duration of each backoff slot is equal to the slot time, and N is an integer greater than or equal to zero. The backoff time can be determined based on the length of the contention window (CW). In an embodiment, the backoff time can be determined based on the frame's AC (Acceptance Time). All backoff slots occur after a DIFS (Distributed Incoming Window) or Extended IFS (EIFS) period, during which the medium is determined to be idle.

[0079] When WLAN device 104 does not detect media activity during a specific backoff time slot, the backoff process should reduce the backoff time by one time slot. When WLAN device 104 determines that the media is busy during the backoff time slot, the backoff process is suspended until the media is again determined to be idle during the DIFS or EIFS period. When the backoff timer reaches zero, WLAN device 104 can perform frame transmission or retransmission.

[0080] The backoff process operates in such a way that when multiple WLAN devices 104 are delaying and executing the backoff process, each WLAN device 104 can use a random function to select the backoff time, and the WLAN device 104 that selects the shortest backoff time may win the competition, thereby reducing the probability of collision.

[0081] Figure 5 A frame transmission process based on Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) for avoiding collisions between frames in a channel, according to an embodiment, is illustrated. Figure 5 The diagram illustrates a first station STA1 transmitting data, a second station STA2 receiving data, and a third station STA3, which may be located in an area capable of receiving frames transmitted from STA1, frames transmitted from STA2, or both. Stations STA1, STA2, and STA3 can be... Figure 1WLAN device 104.

[0082] Station STA1 can determine whether the channel is busy through carrier sensing. Station STA1 can determine channel occupancy / state based on the energy level in the channel or the autocorrelation of the signal in the channel, or it can determine channel occupancy by using a network allocation vector (NAV) timer.

[0083] Once it is determined that the channel is not used by other devices during DIFS (i.e., the channel is idle) (and backoff is performed if necessary), station STA1 can send a Request to Send (RTS) frame to station STA2. Upon receiving the RTS frame, station STA2 can send a Clear to Send (CTS) frame after SIFS as a response to the RTS frame. If dual CTS is enabled and station STA2 is an AP, the AP can send two CTS frames in response to the RTS frame (e.g., the first CTS frame is in a non-high throughput format, and the second CTS frame is in HT format).

[0084] When station STA3 receives an RTS frame, it can use the duration information included in the RTS frame to set its NAV timer for the transmission duration of subsequent frames (e.g., SIFS + CTS frame duration + SIFS + data frame duration + SIFS + ACK frame duration). When station STA3 receives a CTS frame, it can use the duration information included in the CTS frame to set its NAV timer for the transmission duration of subsequent frames. If a new frame is received before the NAV timer expires, station STA3 can update its NAV timer using the duration information included in the new frame. Station STA3 will not attempt to access the channel before the NAV timer expires.

[0085] When station STA1 receives a CTS frame from station STA2, it can send a data frame to station STA2 after the SIFS period has elapsed since the CTS frame was fully received. After successfully receiving the data frame, station STA2 can send an ACK frame as a response to the data frame after the SIFS period has elapsed.

[0086] When the NAV timer expires, the third site STA3 can use carrier sensing to determine if the channel is busy. After determining that the channel has not been used by other devices during the DIFS period after the NAV timer expires, site STA3 can attempt to access the channel after the contention window, according to the backoff procedure.

[0087] When dual CTS is enabled, a station that has acquired a Transmission Opportunity (TXOP) but has no data to send can send a CF-End frame to shorten the TXOP. An AP that receives a CF-End frame with its Basic Service Set Identifier (BSSID) as the destination address can respond by sending two additional CF-End frames: the first CF-End frame using Space-Time Block Codec (STBC), and the second CF-End frame using a non-STBC method. The station that receives the CF-End frame resets its NAV timer to 0 at the end of the PPDU that includes the CF-End frame. Figure 5 The image shows that station STA2 sends an ACK frame to confirm that the receiver has successfully received the frame.

[0088] The IEEE 802.11bn (Ultra-High Reliability, UHR) working group has been formed to address the growing need for higher peak throughput and reliability in Wi-Fi. Figure 6 As shown, the peak PHY rate increases significantly from IEEE 802.11b to IEEE 802.11be (Wi-Fi 7), with the latter focusing on further improving peak throughput. The UHR research group aims to enhance latency distribution and jitter tails to support applications requiring low latency, such as WLAN video transmission, gaming, AR, and VR. It should be noted that various characteristics of UHR (e.g., maximum PHY rate, PHY rate enhancement, bandwidth / spatial stream count, operating frequency band) remain to be determined.

[0089] IEEE 802.11be primarily focuses on indoor and outdoor WLAN operation with stationary and walking speeds in the 2.4, 5, and 6 GHz bands. In addition to peak PHY rates, various candidate features are under discussion. These candidate features include (1) 320 MHz bandwidth and more efficient use of discontinuous spectrum, (2) multi-band / multi-channel aggregation and operation, (3) 16 spatial streams and enhanced multiple-input multiple-output (MIMO) protocols, (4) multi-access point (AP) coordination (e.g., coordinated and joint transmission), (5) enhanced link adaptation and retransmission protocols (e.g., Hybrid Automatic Repeat Request (HARQ)), and (6) adaptation to regulatory rules specific to the 6 GHz spectrum.

[0090] The focus of IEEE 802.11bn (UHR) is still under discussion, with candidate features including MLO enhancements (e.g., in terms of improving throughput / reliability and reducing latency), latency and reliability improvements (e.g., multi-AP coordination to support low-latency traffic), bandwidth expansion (e.g., to 240, 480, 640 MHz), aggregated PPDU (A-PPDU), enhanced multi-link single radio (eMLSR) extension to APs, roaming improvements, and energy-saving schemes to extend battery life.

[0091] Some features, such as increased bandwidth and spatial stream count, are solutions that have proven effective in previous projects focused on improving link throughput, and their feasibility demonstrations are achievable.

[0092] Regarding the operating frequency bands of IEEE 802.11be (e.g., 2.4 / 5 / 6 GHz), since the 6 GHz band (5.925–7.125 GHz) is being considered for unlicensed use, there may be additional unlicensed spectrum available exceeding 1 GHz. This would allow APs and STAs to become tri-band devices. Data transmission frequencies greater than 160 MHz (e.g., 320 MHz or 640 MHz) can be considered to increase the maximum PHY rate. For example, 320 MHz or 160+160 MHz data could be transmitted in the 6 GHz band. Similarly, 160+160 MHz data could be transmitted across the 5 and 6 GHz bands.

[0093] During wireless communication, the transmitting station (STA) creates a Physical Layer Protocol Data Unit (PPDU) frame and sends it to the receiving STA. The receiving STA then receives, detects, and processes the PPDU.

[0094] An Extremely High Throughput (EHT) PPDU frame comprises several parts. It includes a legacy section containing fields such as the Legacy Short Training Field (L-STF), Legacy Long Training Field (L-LTF), Legacy Signal Field (L-SIG), and Repeated Legacy Signal Field (RL-SIG). These fields are used to maintain compatibility with older Wi-Fi standards.

[0095] In addition to the traditional components, EHT PPDU frames also include the Universal Signaling Field (U-SIG), the EHT Signaling Field (EHT-SIG), the EHT Short Training Field (EHT-STF), and the EHT Long Training Field (EHT-LTF). These fields are specific to the EHT standard and are used for various purposes, such as signaling, synchronization, and channel estimation.

[0096] Figure 7 A more detailed description of each field in the EHT PPDU frame is provided, including its purpose and characteristics.

[0097] Regarding the Ultra-High Reliability (UHR) PPDU, its frame structure is currently undefined and will be determined through further discussions by relevant working groups or research groups. This indicates that the specific details of the UHR PPDU are still under development and will be finalized based on the results of future deliberations.

[0098] The distributed nature of channel access networks such as IEEE 802.11 WLANs makes carrier sense mechanisms useful for ensuring collision-free operation. Each station (STA) uses its physical carrier sense to detect transmissions from other STAs. However, in some cases, an STA may fail to detect every transmission. For example, when one STA moves away from another, it may assume the medium is idle and begin sending frames, leading to a collision. To mitigate this hidden node problem, Network Allocation Vector (NAV) was introduced.

[0099] With the continuous development of the IEEE 802.11 standard, scenarios now include multiple users within a Basic Service Set (BSS) that can simultaneously send or receive data, such as cascaded uplink (UL) and downlink (DL) multi-user (MU) transmissions. In these cases, existing carrier sense and NAV mechanisms may be insufficient to meet the requirements, and modified or newly defined mechanisms may be needed to facilitate efficient and collision-free operation.

[0100] For the purposes of this disclosure, MU transmission refers to the situation where multiple frames are simultaneously transmitted to or received from multiple STAs using different resources. Examples of such resources include different frequency resources in Orthogonal Frequency Division Multiple Access (OFDMA) transmissions and different spatial streams in Multi-User Multiple-Input Multiple-Output (MU-MIMO) transmissions. Therefore, downlink OFDMA (DL-OFDMA), downlink MU-MIMO (DL-MU-MIMO), uplink OFDMA (UL-OFDMA), uplink MU-MIMO (UL-MU-MIMO), and OFDMA with MU-MIMO are all considered examples of MU transmissions.

[0101] Figure 8 Examples of multi-user (MU) transport in orthogonal frequency division multiple access (OFDMA) according to some embodiments of the present disclosure are shown.

[0102] In the IEEE 802.11ax and 802.11be specifications, trigger frames play a crucial role in facilitating uplink multi-user (MU) transmissions. The purpose of trigger frames is to allocate resources and request the transmission of one or more trigger-based (TB) physical layer protocol data units (PPDUs) from the associated site (STA).

[0103] The trigger frame contains the information required for the STA to send its uplink TB PPDU. This information includes the trigger type (specifying the type of the expected TB PPDU) and the uplink length (UL length, indicating the duration of the uplink transmission).

[0104] Figure 9An example scenario is shown where an access point (AP) operating in an 80MHz bandwidth environment sends trigger frames to multiple associated STAs. Upon receiving the trigger frames, the STAs respond by sending their respective uplink orthogonal frequency division multiple access (UL OFDMA) TB PPDUs, utilizing allocated resources within the specified 80 MHz bandwidth.

[0105] Upon successfully receiving the UL OFDMA TB PPDU, the AP acknowledges the STA by sending an acknowledgment frame. This acknowledgment can be in the form of an 80MHz wide multi-STA block acknowledgment (Block Ack) or a block acknowledgment using the Direct Feedback (DF) OFDMA method. Multi-STA block acknowledgment allows the AP to acknowledge multiple STAs simultaneously, while block acknowledgment with DF OFDMA enables the AP to provide feedback to the STAs using the same OFDMA technology as in uplink transmissions.

[0106] Trigger frames are a useful component for achieving efficient uplink MU transmission in IEEE 802.11ax and 802.11be networks by allocating resources and coordinating uplink transmissions from multiple STAs within the same bandwidth.

[0107] When the transmitter (TX) does not receive an acknowledgment from the receiver (RX) or the receiver fails to decode a Media Access Control (MAC) Protocol Data Unit (MPDU), a wireless network system can rely on retransmission of the MPDU. Using the Automatic Repeat Request (ARQ) method, the receiver discards the last failed MPDU before receiving a new retransmitted MPDU. With increasing demands for enhanced reliability and reduced latency, wireless network systems can evolve towards a Hybrid ARQ (HARQ) approach.

[0108] There are two methods for HARQ processing. In the first type of HARQ scheme, also known as Catch-up Combined (CC) HARQ (CC-HARQ), the signal to be retransmitted is the same as the previously failed signal because all retransmitted sub-packets use the same puncturing pattern. After encoding with error-correcting codes, puncturing is required to remove some parity bits. The reason CC-HARQ uses the same puncturing pattern is to generate an encoded and decoded data sequence with forward error correction (FEC) and to allow the receiver to use maximum ratio combining (MRC) to combine the received retransmitted bits with the same bits from the previous transmission. For example, the information sequence is transmitted in fixed-length packets. At the receiver, error correction and detection are performed on the entire packet. However, HARQ schemes can be inefficient when burst errors are present. To address this problem more efficiently, sub-packets are used. In sub-packet transmission, only those sub-packets containing errors need to be retransmitted.

[0109] Because the receiver uses currently and previously received sub-packets to decode data, the probability of errors during decoding decreases as the number of sub-packets used increases. The decoding process uses Cyclic Redundancy Check (CRC) and terminates when the entire packet is decoded without errors or when the maximum number of sub-packets is reached. Specifically, the scheme employs a stop-and-wait protocol, such that if the receiver can decode the packet, it sends an acknowledgment (ACK) to the sender. When the sender successfully receives the ACK, it terminates the HARQ transmission for that packet. If the receiver cannot decode the packet, it sends a negative acknowledgment (NAK) to the sender, and the sender performs a retransmission process.

[0110] In the second type of HARQ scheme, also known as Incremental Redundancy (IR) HARQ (IR-HARQ), each sub-packet uses a different puncturing pattern, causing the signal of each retransmitted sub-packet to change compared to the original transmitted sub-packet. IR-HARQ alternates between the two puncturing patterns for odd-numbered and even-numbered transmissions, respectively. The redundancy scheme of IR-HARQ improves the log-likelihood ratio (LLR) of the parity bits to combine information sent across different transmissions due to requests, and reduces the code rate by using additional sub-packets. This results in a lower error rate for sub-packets compared to CC-HARQ. The puncturing pattern used in IR-HARQ is indicated by a Sub-packet Identifier (SPID). The SPID of the first sub-packet may always be set to 0, and all system bits and punctured parity bits are transmitted in the first sub-packet. Self-decoding is possible when the received signal-to-noise ratio (SNR) environment is good (i.e., high SNR). In some embodiments, the sub-packets to be transmitted with corresponding SPIDs are arranged in ascending order of SPIDs, but can be swapped / switched except for the first SPID.

[0111] AP coordination has been considered a potential technology for improving WLAN system throughput in the IEEE 802.11be standard and is still under discussion in the IEEE 802.11bn (UHR) standard. To support various AP coordination schemes, such as coordinated beamforming, OFDMA, TDMA, spatial multiplexing, and joint transmission, predefined mechanisms for APs are required.

[0112] In the context of Coordinated TDMA (C-TDMA), the AP that acquires a Transmission Opportunity (TXOP) is called the sharing AP. This AP initiates an AP coordination scheme to determine the AP candidate set by sending frames (such as beacon frames or probe response frames) that include information about the AP coordination scheme's capabilities. The AP that participates in the AP coordination scheme after receiving a frame from the sharing AP is called the shared AP. The sharing AP is also called the master AP or coordinating AP, while the shared AP is called the slave AP or coordinated AP.

[0113] The operation of various AP coordination schemes has been discussed in the IEEE 802.11be and UHR standards:

[0114] Coordinated Beamforming (C-BF): Multiple APs coordinate and form spatial nulls to transmit on the same frequency resource, allowing simultaneous transmission from multiple APs.

[0115] Coordinated OFDMA (C-OFDMA): The AP achieves more efficient spectrum utilization by coordinating and dividing the spectrum for transmission on orthogonal frequency resources.

[0116] Joint Transmission (JTX): Multiple access points (APs) jointly transmit data to a given user by sharing data among themselves.

[0117] Coordinated Space Reuse (C-SR): Multiple APs or STAs adjust their transmit power to reduce interference between APs.

[0118] By implementing these AP coordination schemes, WLAN systems can leverage cooperation among multiple APs to improve their overall throughput and efficiency.

[0119] C-SR is a multi-AP coordination scheme being considered for future wireless networks (e.g., those implementing the upcoming IEEE 802.11bn wireless network standard, i.e., UHR) to improve spectral efficiency and throughput. C-SR is attractive because it is simple to implement compared to other multi-AP coordination schemes. C-SR allows two BSSs to transmit / receive simultaneously within the same transmission opportunity (TXOP). During C-SR, it is important that the two BSSs control their transmit power to avoid interfering with each other's transmissions.

[0120] Figure 10 This is a schematic diagram illustrating two main stages of the C-SR process according to some embodiments.

[0121] The C-SR process can be performed in a wireless network including a first AP (AP1), a second AP (AP2), a STA associated with AP1 (STA11), and a STA associated with AP2 (STA21). AP1 and STA11 may belong to the first BSS. AP2 and STA21 may belong to the second BSS. AP1 and AP2 can coordinate with each other to implement C-SR. In this example, AP1 is the sharing AP, and AP2 is the shared AP. The sharing AP can be the AP that initiates multi-AP coordination (e.g., for C-SR). The shared AP can be the AP that participates in multi-AP coordination with the sharing AP in response to the initiation of the sharing AP.

[0122] During downlink C-SR, AP1 and AP2 can simultaneously transmit downlink frames to STA11 and STA21, respectively. AP1's downlink transmission may cause interference at STA21 (X1), while AP2's downlink transmission may cause interference at STA11 (X2). To successfully achieve downlink C-SR, AP1 and AP2 need to control their downlink transmit power to avoid / reduce the amount of downlink interference at the STAs.

[0123] As shown in the figure, the C-SR process can include two main phases: an interference measurement phase and a C-SR transmission phase. The interference measurement phase may involve determining the amount of interference at STA11 and STA12. The interference amounts at STA11 and STA12 can be used to determine the transmit power that AP1 and AP2 should use to avoid / reduce downlink interference. During the C-SR transmission phase, AP1 and AP2 can simultaneously transmit downlink frames to STA11 and STA21 using the determined transmit power, respectively, to achieve C-SR.

[0124] Distributed subcarrier RU (dRU) is a physical layer feature being considered for future wireless networks to improve spectral efficiency. dRUs may help overcome power spectral density (PSD) limitations. Various power modes are defined in the 6 GHz band, such as standard power (SP) mode, very low power (VLP) mode, and low power indoor (LPI) mode. PSD limitations are very stringent, especially in VLP and LPI modes in the 6 GHz band, particularly for non-AP STAs. For example, the PSD limitation for non-AP STAs in LPI mode is -1 dBM / MHz. Therefore, using many RU subcarriers within a limited bandwidth will reduce transmit power due to the strict PSD limitations.

[0125] To successfully implement C-SR, it is important to control the transmit power of each BSS so that simultaneous transmissions by BSSs do not interfere with each other. The maximum permissible transmit power of a BSS can be determined by the allowable interference level.

[0126] Figure 11 and Figure 12 This is a schematic diagram illustrating the communication sequence during the interference measurement phase. Figure 11 The communication sequence shown is with Figure 12 The difference between the communication sequences shown is that the measurement frames (e.g., Figure 11 Frames 1110 and 1115 shown are in Figure 11 The communication sequence shown is transmitted simultaneously, while measurement frames (e.g., Figure 12 Frames 1210 and 1215 shown are in Figure 12 The communication sequence shown transmits sequentially (not simultaneously). Figure 11 The communication sequence shown may be referred to as Option 1 in this document. Figure 12 The communication sequence shown can be referred to as Option 2 in this paper.

[0127] Figure 11 This is a schematic diagram illustrating a communication sequence during the interference measurement phase according to some embodiments.

[0128] As shown in the figure, AP1 can send an M-AP trigger frame 1105 (“M-AP TF”) to AP2 to cause AP2 to send a measurement frame. The M-AP trigger frame 1105 may include information about the transmit power and / or modulation codec scheme (MCS) used by AP2 to send the measurement frame. As used herein, the M-AP trigger frame can be any type of frame that can be used to initiate coordination between multiple APs.

[0129] After sending M-AP trigger frame 1105, AP1 can send measurement frame 1110 to STA11. Furthermore, in response to receiving M-AP trigger frame 1105, AP2 can send measurement frame 1115 to STA21. In the example shown in the figure (reflecting Option 1), AP1 sending measurement frame 1110 and AP2 sending measurement frame 1115 occur simultaneously. The transmission of measurement frames allows the STA to determine the amount of interference caused by the Overlapping BSS (OBSS). In the example shown in the figure, each AP sends a single measurement frame. In some embodiments, each AP can send multiple frames to allow the STA to determine the amount of interference caused by the OBSS. For example, each AP can sequentially send a Null Packet Advertisement (NDP) frame and an NDP frame. As used herein, a measurement frame can be any type of frame sent for the purpose of allowing the device receiving / listening to the frame to determine / measure the channel state / characteristics based on the frame.

[0130] STA11 can determine the amount of interference (X2) caused by the second BSS based on the received signal strength (e.g., Received Signal Strength Indication (RSSI)) of measurement frames 1110 and 1115. Similarly, STA21 can determine the amount of interference (X1) caused by the first BSS based on the received signal strength (e.g., Received Signal Strength Indication (RSSI)) of measurement frames 1110 and 1115. The STA can use the preamble and / or data portion of the measurement frame to determine the received signal strength of the measurement frame (e.g., unless the frame is an NDP frame). If it is assumed that the STA knows the transmit power of the measurement frame, any difference between the transmit power and the received signal strength of the measurement frame can be considered as being due to interference.

[0131] AP1 can send interference measurement feedback request frames 1120 (“Request X1 and X2”) to STA11 and STA21 to request interference measurements from STA11 and STA21. In some embodiments, AP1 and AP2 can each send separate interference measurement feedback request frames to request interference measurements from STA11 and STA21. The example shown in the figure is where AP1 sends interference measurement feedback request frames 1120 to STA11 and STA21 to request interference measurements from both STA11 and STA21. In an embodiment, interference measurement feedback request frame 1120 is a beamforming report (BFRP) trigger frame or a variant thereof. In response to receiving interference measurement feedback request frame 1120, STA11 can send a first interference measurement feedback frame 1125 (“Feedback X2”) to the shared AP, which includes an indication of the amount of downlink interference (X2) caused by the second BSS at STA11. Similarly, in response to receiving the interference measurement feedback request frame 1120, STA21 may send a second interference measurement feedback frame 1130 (“Feedback X1”) to the shared AP, which includes an indication of the amount of downlink interference (X1) caused by the first BSS at STA21.

[0132] Upon receiving the interference measurement feedback frame, AP1 can determine the first downlink transmit power to be used and the second downlink transmit power to be used by AP2 based on the downlink interference caused by the second BSS at STA11 and the downlink interference caused by the first BSS at STA21. AP1 can determine the first downlink transmit power and the second downlink transmit power in a manner that reduces the downlink interference caused by AP1 and AP2, thereby achieving C-SR in the downlink direction.

[0133] AP1 can send a power control information frame 1135 (“shared power control information”) to AP2, which includes indications of a first downlink transmit power and a second downlink transmit power. In an embodiment, the power control information frame 1135 includes only an indication of the second downlink transmit power (excluding the first downlink transmit power).

[0134] During the C-SR transmission phase, AP1 can use its first downlink transmit power to send downlink frames to STA11, and AP2 can use its second downlink transmit power to send downlink frames to STA21. Downlink frame transmissions by AP1 and AP2 can occur simultaneously to achieve downlink C-SR.

[0135] Figure 12 This is a schematic diagram illustrating a communication sequence during an interference measurement phase according to some embodiments. The communication sequence shown in the figure involves many... Figure 11 The frames / sequences shown are the same or similar to those described above. Those skilled in the art will understand that the above description... Figure 11The provided description is also applicable Figure 12 The communication sequence is shown. However, for the sake of brevity, not all details are repeated here.

[0136] As shown in the figure, AP1 can send an M-AP trigger frame 1205 (“M-AP TF”) to AP2 to cause AP2 to send a measurement frame.

[0137] After sending M-AP trigger frame 1105, AP1 can send measurement frame 1210 to STA11. Furthermore, in response to receiving M-AP trigger frame 1105, AP2 can send measurement frame 1215 to STA21. In the example shown in the figure (reflecting option 2), measurement frames 1210 and 1215 are sent sequentially (not simultaneously). In an embodiment, M-AP trigger frame 1205 may include an indication of the timing / sequence of the measurement frame transmission.

[0138] STA11 can determine the amount of interference (X2) caused by the second BSS based on the received signal strength (e.g., Received Signal Strength Indication (RSSI)) of measurement frames 1210 and 1215. Similarly, STA21 can determine the amount of interference (X1) caused by the first BSS based on the received signal strength (e.g., Received Signal Strength Indication (RSSI)) of measurement frames 1210 and 1215.

[0139] In an embodiment, if the STA knows the received signal strength of frames previously transmitted by its associated AP, the STA can determine the amount of interference caused by the OBSS at that STA as follows: The STA can determine the received signal strength of frames previously transmitted by its associated AP through a beacon measurement request / report procedure. The STA can listen to measurement frames transmitted by the OBSS AP and measure the received signal strength of those measurement frames. The STA can determine the amount of interference caused by the OBSS at that STA based on the known received signal strength of frames previously transmitted by its associated AP and the received signal strength of measurement frames transmitted by the OBSS AP. For example, STA11 can know the received signal strength of frames previously transmitted by AP1 (STA11's associated AP) through a beacon measurement request / report procedure with AP1. Furthermore, STA11 can listen to measurement frame 1215 transmitted by AP2 (which is the OBSS AP relative to STA11) and measure the received signal strength of measurement frame 1215. STA11 can determine the amount of interference (X2) caused by the second BSS at STA11 based on the known received signal strength of frames previously transmitted by AP1 and the received signal strength of measurement frame 1215. STA21 can determine the amount of interference (X1) caused by the first BSS at STA21 in a similar manner.

[0140] In an embodiment, if the STA is unaware of the received signal strength of frames previously transmitted by its associated AP, the STA can determine the amount of interference caused by the OBSS at that STA as follows: The STA can measure the received signal strength of measurement frames transmitted by its associated AP. Furthermore, the STA can measure the received signal strength of measurement frames transmitted by the OBSS AP. Based on the received signal strength of measurement frames transmitted by its associated AP and the OBSS AP, the STA can implicitly determine the amount of interference caused by the OBSS at that STA. For example, STA11 can measure the received signal strength of measurement frame 1210 transmitted by AP1 (STA11's associated AP). Furthermore, STA11 can measure the received signal strength of measurement frame 1215 transmitted by AP2 (which is the OBSS AP relative to STA11). Based on the received signal strength of measurement frame 1210 transmitted by AP1 and measurement frame 1215 transmitted by AP2, STA11 can implicitly determine the amount of interference (X2) caused by the second BSS at that STA. STA21 can implicitly determine the amount of interference (X1) caused by the first BSS at STA21 in a similar manner.

[0141] AP1 can send interference measurement feedback request frames 1220 (“Request X1 and X2”) to STA11 and STA21 to request interference measurements from STA11 and STA21. In response to receiving the interference measurement feedback request frame 1220, STA11 can send a first interference measurement feedback frame 1225 (“Feedback X2”) to the shared AP, which includes an indication of the amount of downlink interference (X2) caused by the second BSS at STA11. Similarly, in response to receiving the interference measurement feedback request frame 1220, STA21 can send a second interference measurement feedback frame 1230 (“Feedback X1”) to the shared AP, which includes an indication of the amount of downlink interference (X1) caused by the first BSS at STA21.

[0142] Upon receiving the interference measurement feedback frame, AP1 can determine the first downlink transmit power to be used and the second downlink transmit power to be used by AP2 based on the downlink interference caused by the second BSS at STA11 and the downlink interference caused by the first BSS at STA21. AP1 can determine the first downlink transmit power and the second downlink transmit power in a manner that reduces the downlink interference caused by AP1 and AP2, thereby achieving C-SR in the downlink direction.

[0143] AP1 can send a power control information frame 1235 (“Shared Power Control Information”) to AP2, which includes an indication of the second downlink transmit power.

[0144] During the C-SR transmission phase, AP1 can use its first downlink transmit power to send downlink frames to STA11, and AP2 can use its second downlink transmit power to send downlink frames to STA21. Downlink frame transmissions by AP1 and AP2 can occur simultaneously to achieve downlink C-SR.

[0145] Interference measurements may also be needed to implement C-SR in the uplink direction. STA can be transmitted in the dRU in the uplink direction to increase transmit power.

[0146] Figure 13 This is a schematic diagram illustrating uplink interference during C-SR in a wireless network according to some embodiments.

[0147] The diagram illustrates its configuration and... Figure 10 The wireless network shown is a similar wireless network. For example, this wireless network includes AP1, AP2, STA11, and STA21. AP1 and STA11 can belong to the first BSS. AP2 and STA21 can belong to the second BSS. AP1 and AP2 can coordinate with each other to implement C-SR. AP1 is a shared AP, and AP2 is a shared AP.

[0148] During uplink C-SR, STA11 and STA21 can simultaneously transmit uplink frames to AP1 and AP2, respectively. STA11's uplink transmission can cause interference (Y1) at AP2, and STA2's uplink transmission can cause interference (Y2) at AP1. To successfully achieve uplink C-SR, STA11 and STA21 need to control their uplink transmit power to avoid / reduce uplink interference. Additionally, STA11 and STA21 can transmit their uplink frames in the dRU at a higher transmit power.

[0149] The technique described herein allows an AP to determine the amount of uplink interference at the AP relative to a dRU, so that the AP can determine the appropriate transmit power that the STA should apply for uplink transmissions to the AP in the dRU to achieve uplink C-SR. It is assumed that the dRU used by the STA for uplink transmissions is predefined or otherwise known. In an embodiment, the STA transmits an interference measurement feedback frame in the dRU (e.g., ...). Figure 11Interference measurement feedback frames 1125 and 1130 are shown. The AP can implicitly determine the amount of uplink interference caused by its own BSS and the amount of uplink interference caused by the OBSS based on the received signal strength of the interference measurement feedback frame. The AP can determine the uplink transmit power used by the STA for uplink transmission based on the amount of uplink interference caused by its own BSS and the amount of uplink interference caused by the OBSS. Having the STA send the interference measurement feedback frame in the dRU allows the AP to determine the amount of uplink interference in the dRU without additional overhead (e.g., without sending / swapping additional frames). That is, the interference measurement feedback frames can provide a dual function: (1) they provide information about the amount of downlink interference at the STA; and (2) they act as “measurement” frames in the uplink direction, allowing the AP to determine the amount of uplink interference caused by the OBSS at the AP.

[0150] Figure 14 This is a schematic diagram illustrating a communication sequence for an interference measurement phase that allows determination of the uplink interference amount of a dRU, according to some embodiments. The diagram shows two examples of the communication sequences. In the first communication sequence, measurement frames are transmitted simultaneously. In the second communication sequence, measurement frames are transmitted sequentially (not simultaneously).

[0151] In the first example, as shown in the figure, AP1 can send an M-AP trigger frame 1402 (“M-AP TF”) to AP2 to cause AP2 to send a measurement frame.

[0152] After sending M-AP trigger frame 1402, AP1 can send measurement frame 1404 to STA11. Furthermore, in response to receiving M-AP trigger frame 1402, AP2 can send measurement frame 1406 to STA21. In the first example, measurement frames 1404 and 1406 are sent simultaneously.

[0153] STA11 can determine the amount of downlink interference (X2) caused by the second BSS based on the received signal strength (e.g., Received Signal Strength Indication (RSSI)) of measurement frames 1404 and 1406. Similarly, STA21 can determine the amount of downlink interference (X1) caused by the first BSS based on the received signal strength (e.g., Received Signal Strength Indication (RSSI)) of measurement frames 1404 and 1406.

[0154] AP1 can send interference measurement feedback request frames 1408 (“Request X1 and X2”) to STA11 and STA21 to request interference measurements from STA11 and STA21. In response to receiving the interference measurement feedback request frame 1408, STA11 can send a first interference measurement feedback frame 1410 (“Feedback X2 in dRU”) to the shared AP from the dRU. The first interference measurement feedback frame 1410 may include an indication of the amount of downlink interference (X2) caused by the second BSS at STA11. Similarly, in response to receiving the interference measurement feedback request frame 1408, STA21 can send a second interference measurement feedback frame 1412 (“Feedback X1 in dRU”) to AP1 from the dRU. The second interference measurement feedback frame 1412 may include an indication of the amount of downlink interference (X1) caused by the first BSS at STA21.

[0155] AP1 can determine the uplink interference (Y2) caused by the second BSS at AP1 and the uplink interference (Y1) caused by the first BSS at AP2 based on the received signal strength of the first interference measurement feedback frame 1410 and the second interference measurement feedback frame 1412. For example, AP1 can know the transmit power of the first interference measurement feedback frame 1410 and the second interference measurement feedback frame 1412. Furthermore, AP1 can use the preamble and / or data portions of these frames to determine the received signal strength of these frames. Any difference between the transmit power and the received signal strength of these frames can be considered as being due to interference. In an embodiment, AP2 determines the uplink interference (Y1) caused by the first BSS at AP2 and provides this information to AP1.

[0156] AP1 can determine the first downlink transmit power to be used by AP1 and the second downlink transmit power to be used by AP2 based on the downlink interference (X2) caused by the second BSS at STA11 and the downlink interference (X1) caused by the first BSS at STA21. Furthermore, AP1 can determine the first uplink transmit power to be used by STA11 and the second uplink transmit power to be used by STA21 based on the uplink interference (Y2) caused by the second BSS at AP1 and the uplink interference (Y1) caused by the first BSS at AP2.

[0157] AP1 can send a power control information frame 1414 (“shared power control information”) to AP2, which includes indications of a first downlink transmit power, a second downlink transmit power, a first uplink transmit power, and a second uplink transmit power. In an embodiment, the power control information frame 1414 includes only indications of the second downlink transmit power and the second uplink transmit power (excluding the first downlink transmit power and the first uplink transmit power).

[0158] During the C-SR transmission phase, AP1 may send trigger frame 1416 (“TF”) to STA11 to request uplink transmission from STA11, and AP2 may send trigger frame 1418 (“TF”) to STA21 to request uplink transmission from STA21. AP1 sending trigger frame 1416 and AP2 sending trigger frame 1418 can occur simultaneously. AP1 may send trigger frame 1416 using a first downlink transmit power, and AP2 may send trigger frame 1418 using a second downlink transmit power to achieve downlink C-SR. Trigger frame 1416 may include an indication of the first uplink transmit power, and trigger frame 1418 may include an indication of the second uplink transmit power. In response to receiving trigger frame 1416, STA11 may send uplink frame 1420 (“UL data”) to AP1 in the dRU, and STA21 may send uplink frame 1422 (“UL data”) to AP2 in the dRU. STA11 sending uplink frame 1420 and STA21 sending uplink frame 1422 can occur simultaneously. STA11 can transmit uplink frame 1420 using the first uplink transmit power indicated in trigger frame 1416, and STA21 can transmit uplink frame 1422 using the second uplink transmit power indicated in trigger frame 1418, to achieve C-SR in the uplink direction.

[0159] In response to receiving uplink frame 1420, AP1 can send an acknowledgment frame 1424 (“ACK”) to STA11. Furthermore, in response to receiving uplink frame 1422, AP2 can send an ACK frame 1426 (“ACK”) to STA21. AP1 sending ACK frame 1424 and AP2 sending ACK frame 1426 can occur simultaneously.

[0160] In the second example, as shown in the figure, AP1 can send an M-AP trigger frame 1402 (“M-AP TF”) to AP2 to cause AP2 to send a measurement frame.

[0161] After sending M-AP trigger frame 1452, AP1 can send measurement frame 1454 to STA11. Furthermore, in response to receiving M-AP trigger frame 1452, AP2 can send measurement frame 1456 to STA21. In the second example, measurement frames 1454 and 1456 are sent sequentially (not simultaneously). In this embodiment, the timing / sequence of the measurement frame transmissions is indicated in M-AP trigger frame 1452.

[0162] AP1 can send an interference measurement feedback request frame 1458 (“Request X1 and X2”) to STA11 and STA21 to request interference measurements from STA11 and STA21. In response to receiving the interference measurement feedback request frame 1458, STA11 can send a first interference measurement feedback frame 1460 (“Feedback X2 in dRU”) to AP1 from the dRU. The first interference measurement feedback frame 1460 may include an indication of the amount of downlink interference (X2) caused by the second BSS at STA11. Similarly, in response to receiving the interference measurement feedback request frame 1458, STA21 can send a second interference measurement feedback frame 1462 (“X1 in dRU”) to AP1 from the dRU. The second interference measurement feedback frame 1462 may include an indication of the amount of downlink interference (X1) caused by the first BSS at STA21.

[0163] AP1 can determine the uplink interference amount (Y2) caused by the second BSS and the uplink interference amount (Y1) caused by the first BSS based on the received signal strength of the first interference measurement feedback frame 1460 and the second interference measurement feedback frame 1462.

[0164] AP1 can determine the first downlink transmit power to be used by AP1 and the second downlink transmit power to be used by AP2 based on the downlink interference (X2) caused by the second BSS at STA11 and the downlink interference (X1) caused by the first BSS at STA21. Furthermore, AP1 can determine the first uplink transmit power to be used by STA11 and the second uplink transmit power to be used by STA21 based on the uplink interference (Y2) caused by the second BSS at AP1 and the uplink interference (Y1) caused by the first BSS at AP2.

[0165] AP1 can send a power control information frame 1464 (“shared power control information”) to AP2, which includes indications of a first downlink transmit power, a second downlink transmit power, a first uplink transmit power, and a second uplink transmit power. In an embodiment, the power control information frame 1464 includes only indications of the second downlink transmit power and the second uplink transmit power (excluding the first downlink transmit power and the first uplink transmit power).

[0166] During the C-SR transmission phase, AP1 can send trigger frame 1466 (“TF”) to STA11 to request uplink transmission from STA11, and AP2 can send trigger frame 1468 (“TF”) to STA21 to request uplink transmission from STA21. AP1 sending trigger frame 1466 and AP2 sending trigger frame 1468 can occur simultaneously. AP1 can send trigger frame 1466 using a first downlink transmit power, and AP2 can send trigger frame 1468 using a second downlink transmit power to achieve downlink C-SR. Trigger frame 1466 may include an indication of the first uplink transmit power, and trigger frame 1468 may include an indication of the second uplink transmit power. In response to receiving trigger frame 1466, STA11 can send uplink frame 1470 (“UL data”) to AP1 in the dRU, and STA21 can send uplink frame 1472 (“UL data”) to AP2 in the dRU. STA11 sending uplink frame 1470 and STA21 sending uplink frame 1472 can occur simultaneously. STA11 can transmit uplink frame 1470 using the first uplink transmit power indicated in trigger frame 1466, and STA21 can transmit uplink frame 1472 using the second uplink transmit power indicated in trigger frame 1468, to achieve C-SR in the uplink direction.

[0167] In response to receiving uplink frame 1470, AP1 can send ACK frame 1474 (“ACK”) to STA11. Furthermore, in response to receiving uplink frame 1472, AP2 can send ACK frame 1476 (“ACK”) to STA21. AP1 sending ACK frame 1474 and AP2 sending ACK frame 1476 can occur simultaneously.

[0168] While specific communication sequences are illustrated in the figures and described herein, those skilled in the art will understand that the communication sequences can be modified to achieve the same results / effects without departing from the spirit and scope of this disclosure. Therefore, the communication sequences shown in the figures should be considered illustrative rather than restrictive.

[0169] The techniques described herein allow the STA to provide information to the AP regarding the amount of downlink interference at the STA. The AP can use this feedback information to control and coordinate the downlink transmit power of the AP to achieve successful C-SR (interference-free) in the downlink direction. Furthermore, the STA can send interference measurement feedback frames from the dRU to the AP, enabling the AP to determine the amount of uplink interference at the dRU without incurring additional overhead. The AP can leverage its knowledge of the uplink interference at the dRU to control the uplink transmit power of the STA to achieve successful C-SR (interference-free) in the uplink direction.

[0170] Various embodiments are described in the context of requesting / acquiring interference measurements for use in C-SR. However, it should be understood that the embodiments are not limited thereto. The techniques described herein can be used to request / acquire other types of channel information for other multi-AP coordination schemes. More generally, a first AP may send an M-AP frame to cause a second AP to send a measurement frame. STAs associated with the first AP may determine channel information based on the measurement frames sent by the second AP (and in some cases, also based on the measurement frames sent by the first AP). The first AP may then send a channel information feedback request frame to request channel information from the associated STA. In response to receiving the channel information feedback request frame, the STA may send a channel information feedback frame containing the channel information to the first AP. In this way, the first AP is able to determine how the second AP affects the channel state at its associated STAs.

[0171] Now for reference Figure 15 The following describes a method 1500 for implementing C-SR in the downlink direction according to an example embodiment. Method 1500 can be performed by a shared AP belonging to a first BSS to implement C-SR with a shared AP belonging to a second BSS. The shared AP can be implemented by a wireless device (e.g., wireless device 104).

[0172] Furthermore, although shown in a specific order, in some embodiments, the operations of method 1500 (and other methods shown in the figures) may be performed in a different order. For example, although the operations of method 1500 are shown to be performed sequentially, some operations may be performed in partially or completely overlapping time periods.

[0173] In operation 1505, the sharing AP sends an M-AP trigger frame to the shared AP.

[0174] In operation 1510, after sending the M-AP trigger frame, the sharing AP sends a first measurement frame to a first STA belonging to a first BSS, wherein the shared AP, in response to receiving the M-AP trigger frame from the sharing AP, sends a second measurement frame to a second STA belonging to a second BSS. In an embodiment, the M-AP trigger frame includes information about the transmit power used by the shared AP to send the second measurement frame. In an embodiment, the first measurement frame includes multiple frames. In an embodiment, the multiple frames include NDPA frames and NDP frames. In an embodiment, the first measurement frame and the second measurement frame are sent simultaneously. In an embodiment, the first measurement frame and the second measurement frame are not sent simultaneously.

[0175] In operation 1515, the shared AP sends an interference measurement feedback request frame to request interference measurements from the first STA. In this embodiment, the interference measurement feedback request frame is a BFRP trigger frame or a variant thereof.

[0176] In operation 1520, the shared AP receives an interference measurement feedback frame from the first STA as a response to an interference measurement feedback request frame. The interference measurement feedback frame includes an indication of the amount of first downlink interference caused by a second measurement frame at the first STA. In this embodiment, the interference measurement feedback frame is transmitted by the first STA in the dRU.

[0177] In operation 1525, the shared AP determines the amount of second downlink interference caused by the first measurement frame at the second STA. In an embodiment, the interference measurement feedback request frame also requests interference measurement from the second STA, wherein the second downlink interference amount is determined based on an indication of the second downlink interference amount included in the interference measurement feedback frame received from the second STA.

[0178] In operation 1530, the sharing AP determines the first downlink transmit power to be used by the sharing AP and the second downlink transmit power to be used by the shared AP based on the first downlink interference and the second downlink interference.

[0179] In operation 1535, the sharing AP sends a power control information frame to the shared AP, the power control information frame including an indication of a second downlink transmit power. In an embodiment, the power control information frame also includes an indication of a first downlink transmit power.

[0180] In operation 1540, the shared AP uses the first downlink transmit power to send the first downlink frame to the first STA, while the shared AP simultaneously uses the second downlink transmit power to send the second downlink frame to the second STA.

[0181] Next reference Figure 16 This document describes a method 1600 for implementing uplink C-SR according to an example embodiment. Method 1600 can be performed by a sharing AP that works in conjunction with the shared AP. The sharing AP may belong to a first BSS, and the shared AP may belong to a second BSS. The sharing AP may be implemented by a wireless device (e.g., wireless device 104). As described above, the sharing AP can combine method 1500 with method 1600 to implement C-SR in both downlink and uplink directions with minimal overhead.

[0182] In operation 1605, the shared AP determines a first uplink interference amount at the shared AP and a second uplink interference amount at the shared AP based on the received signal strength of a first interference measurement feedback frame (e.g., in a dRU) received by a first STA belonging to a first BSS and the received signal strength of a second interference measurement feedback frame sent by a second STA belonging to a second BSS.

[0183] In operation 1610, the shared AP determines a first uplink transmit power to be used by the first STA and a second uplink transmit power to be used by the second STA based on a first uplink interference amount and a second uplink interference amount, wherein the indication of the second uplink transmit power is included in a power control information frame sent by the shared AP to the shared AP.

[0184] In operation 1615, the shared AP sends a first trigger frame to the first STA, which requests uplink transmission from the first STA, and the first trigger frame includes an indication of a first uplink transmit power. The shared AP may simultaneously send a second trigger frame to the second STA, which requests uplink transmission from the second STA, and the second trigger frame includes an indication of a second uplink transmit power.

[0185] In operation 1620, the shared AP receives a first uplink frame from a first STA in response to a first trigger frame, wherein the first STA transmits the first uplink frame to the shared AP (e.g., in the dRU) using a first uplink transmit power (indicated in the first trigger frame). The second STA may simultaneously transmit a second uplink frame to the shared AP using a second uplink transmit power (indicated in the first trigger frame) in response to the second trigger frame.

[0186] Now for reference Figure 17 The following describes a method 1700 for providing downlink interference measurement feedback information according to an exemplary embodiment. Method 1700 can be performed by a STA to provide downlink interference measurement feedback information to an AP. The STA and AP can belong to a first BSS that overlaps with a second BSS. The STA can be implemented by a wireless device (e.g., wireless device 104).

[0187] In operation 1705, the STA determines the amount of downlink interference caused by the second BSS at the STA.

[0188] In operation 1710, the STA receives an interference measurement feedback request frame from the AP requesting interference measurements. In this embodiment, the interference measurement feedback request frame is a BFRP trigger frame or a variant thereof.

[0189] In operation 1715, in response to receiving an interference measurement feedback request frame, the STA sends an interference measurement feedback frame to the AP (e.g., in the dRU), which includes an indication of the amount of downlink interference at the STA.

[0190] In an embodiment, during operation 1720, the STA receives a downlink frame from the AP, wherein the downlink frame is transmitted by the AP using a downlink transmit power determined by the downlink interference at the STA and the downlink interference caused by the first BSS at the second STA belonging to the second BSS, wherein the second AP belonging to the second BSS simultaneously transmits a downlink frame to the second STA to implement C-SR in the downlink direction.

[0191] In one embodiment, during operation 1725, the STA receives a trigger frame from the AP requesting uplink transmission from the STA, wherein the trigger frame includes an indication of the uplink transmit power to be used by the STA.

[0192] In an embodiment, during operation 1730, in response to receiving a trigger frame, the STA transmits an uplink frame to the AP in the dRU using the uplink transmit power (indicated in the trigger frame).

[0193] In an embodiment, the STA receives a first measurement frame from the AP, determines the received signal strength of the first measurement frame, listens to a second measurement frame sent by a second AP belonging to a second BSS, and determines the received signal strength of the second measurement frame. The STA can determine the amount of downlink interference (caused by the second BSS at the STA) based on the received signal strength of the first and second measurement frames. In an embodiment, the first measurement frame includes multiple frames. In an embodiment, these multiple frames include NDPA frames and NDP frames.

[0194] In an embodiment, the STA listens to measurement frames sent by the second AP belonging to the second BSS and determines the received signal strength of the measurement frame. The STA can determine the amount of downlink interference (caused by the second BSS at the STA) based on the received signal strength obtained through the beacon measurement request / report phase with the AP and the received signal strength of the measurement frame.

[0195] Now for reference Figure 18 The present invention will describe a method 1800 for acquiring channel information according to an exemplary embodiment. Method 1800 may be performed by a first AP to acquire channel information in coordination with a second AP. The first AP may belong to a first BSS, and the second AP may belong to a second BSS. The first AP may be implemented by a wireless device (e.g., wireless device 104).

[0196] In operation 1805, the first AP sends a multi-AP (M-AP) trigger frame to the second AP, so that the second AP sends a measurement frame.

[0197] In operation 1810, the first AP sends a Channel Information Feedback Request frame to request channel information from STAs belonging to the first BSS. In this embodiment, the Channel Information Feedback Request frame is a BFRP trigger frame or a variant thereof.

[0198] In operation 1815, the first AP receives a channel information feedback frame, including channel information, from the STA as a response to a channel information feedback request frame, wherein the channel information is determined by the STA based on a measurement frame sent by the second AP. In this embodiment, the measurement frame is an NDP frame.

[0199] In one embodiment, the first AP transmits a second measurement frame simultaneously with the measurement frame transmitted by the second AP, wherein the channel information included in the channel information feedback frame is further determined by the STA based on the second measurement frame transmitted by the first AP. In another embodiment, the channel information included in the channel information feedback frame includes information about the amount of interference caused at the STA by the measurement frame transmitted by the second AP.

[0200] Now for reference Figure 19 The present invention will describe a method 1900 for providing channel information according to an exemplary embodiment. Method 1900 may be performed by a STA to provide channel information to a first AP coordinating with a second AP. The first AP and the STA may belong to a first BSS, and the second AP may belong to a second BSS. The STA may be implemented by a wireless device (e.g., wireless device 104).

[0201] In operation 1905, the STA receives measurement frames from the second AP belonging to the second BSS.

[0202] In operation 1910, the STA determines channel information based on the measurement frame. In an embodiment, the measurement frame is an NDP frame. In an embodiment, the STA receives a second measurement frame from the first AP while simultaneously receiving the measurement frame from the second AP. The STA can further determine channel information based on the second measurement frame. In an embodiment, the channel information includes information about the amount of interference caused at the STA by the measurement frame received from the second AP.

[0203] In operation 1915, the STA receives a channel information feedback request frame from the first AP, which requests channel information. In this embodiment, the channel information feedback request frame is a BFRP trigger frame or a variant thereof.

[0204] In operation 1920, in response to receiving a channel information feedback request frame, the STA sends a channel information feedback frame including channel information to the first AP.

[0205] While many of the solutions and techniques described herein are based on WLAN systems, it should be understood that these solutions and techniques are also applicable to other network environments, such as cellular telecommunications networks, wired networks, etc. In some embodiments, the solutions and techniques provided herein may be embodied in or in an article of manufacture in which instructions are stored on a non-transitory machine-readable medium (e.g., microelectronic memory) that program one or more data processing components (collectively referred to herein as “processors” or “processing units”) to perform the operations described herein. In other embodiments, some of these operations may be performed by specific hardware components containing hard-wired logic (e.g., dedicated digital filter blocks and state machines). These operations may alternatively be performed by any combination of programmed data processing components and fixed hard-wired circuit components.

[0206] In some cases, an embodiment may be an apparatus (e.g., an AP STA, non-AP STA, or other network or computing device) that includes one or more hardware and software logic structures for performing one or more of the operations described herein. For example, as described herein, the apparatus may include a storage unit that stores instructions executable by a hardware processor mounted in the apparatus. The apparatus may also include one or more other hardware or software elements, including network interfaces, display devices, etc.

[0207] Some of the parts described in detail above are presented in symbolic representations of algorithms and data bit operations within computer memory. These algorithmic descriptions and representations are the most effective way for those skilled in the art of data processing to communicate the essence of their work to others skilled in the art. Algorithms are, and are generally considered, a self-consistent sequence of operations that leads to a desired result. These operations are those that require physical manipulation of physical quantities. Typically, though not always, these quantities are in the form of electrical or magnetic signals that can be stored, combined, compared, and otherwise manipulated. Sometimes, primarily for reasons of general use, it is convenient to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, etc.

[0208] However, it should be remembered that all these and similar terms are associated with appropriate physical quantities and are merely convenient labels applied to those quantities. This disclosure may relate to the actions and processes of computer systems or similar electronic computing devices that manipulate and transform data represented as physical (electronic) quantities in the registers and memories of the computer system into other data similarly represented as physical quantities in the computer system's memory or registers or other such information storage systems.

[0209] This disclosure also relates to apparatus for performing the operations described herein. Such apparatus may be specifically constructed for a particular purpose, or it may comprise a general-purpose computer selectively activated or reconfigured by a computer program stored in a computer. For example, a computer system or other data processing system may perform the computer-implemented methods described herein in response to its processor executing a computer program (e.g., a sequence of instructions) contained in memory or other non-transitory machine-readable storage medium. Such a computer program may be stored in a computer-readable storage medium, such as, but not limited to, any type of disk, including floppy disks, optical disks, CD-ROMs and magneto-optical disks, read-only memory (ROM), random access memory (RAM), EPROM, EEPROM, magnetic cards or optical cards, or any type of medium suitable for storing electronic instructions, each medium coupled to a computer system bus.

[0210] The algorithms and displays presented herein are not inherently linked to any particular computer or other device. Various general-purpose systems can be used with the programs taught herein, or it may be more convenient to construct more specialized devices to perform the methods. The structures of many such systems will be described below. Furthermore, this disclosure does not refer to any particular programming language. It should be understood that the teachings of this disclosure as described herein can be implemented using various programming languages.

[0211] This disclosure may be provided as a computer program product or software, which may include a machine-readable medium having instructions stored thereon that can be used to program a computer system (or other electronic device) to perform processes according to this disclosure. A machine-readable medium includes any mechanism that stores information in a machine-readable (e.g., computer-readable) form. In some embodiments, a machine-readable medium includes a machine-readable storage medium, such as a read-only memory (“ROM”), random access memory (“RAM”), a disk storage medium, an optical storage medium, a flash memory assembly, etc.

[0212] In the foregoing specification, embodiments of the present disclosure have been described with reference to specific exemplary embodiments. It will be apparent that various modifications may be made to the embodiments of the present disclosure without departing from the broader spirit and scope set forth in the appended claims. Therefore, the specification and drawings should be considered illustrative rather than restrictive.

Claims

1. A method for implementing Cooperative Spatial Reuse (C-SR) with a shared access point (AP) for use with a shared AP, wherein the shared AP belongs to a first Basic Service Set (BSS) and the shared AP belongs to a second BSS, the method comprising: Send a multi-AP, M-AP, trigger frame to the shared AP; After sending the M-AP trigger frame, a first measurement frame is sent to a first STA belonging to the first BSS, wherein the shared AP, in response to receiving the M-AP trigger frame from the shared AP, sends a second measurement frame to a second STA belonging to the second BSS; Send an interference measurement feedback request frame to request interference measurements from the first STA; In response to the interference measurement feedback request frame, an interference measurement feedback frame is received from the first STA, the interference measurement feedback frame including an indication of a first downlink interference amount caused at the first STA by the second measurement frame; Determine the amount of second downlink interference caused by the first measurement frame at the second STA; Based on the first downlink interference and the second downlink interference, the first downlink transmit power to be used by the shared AP and the second downlink transmit power to be used by the shared AP are determined. Send a power control information frame to the shared AP, the power control information frame including an indication of the second downlink transmit power; and The first downlink frame is sent to the first STA using the first downlink transmit power, wherein the shared AP simultaneously sends a second downlink frame to the second STA using the second downlink transmit power.

2. The method of claim 1, wherein the M-AP trigger frame includes information related to the transmit power to be used by the shared AP to transmit the second measurement frame.

3. The method according to claim 1, wherein the first measurement frame comprises a plurality of frames.

4. The method of claim 3, wherein the plurality of frames includes a Null Packet Announcement (NDPA) frame and a Null Packet Announcement (NDP) frame.

5. The method according to claim 1, wherein the first measurement frame and the second measurement frame are transmitted simultaneously.

6. The method according to claim 1, wherein the first measurement frame and the second measurement frame are not sent simultaneously.

7. The method of claim 1, wherein the interference measurement feedback request frame further requests interference measurement from the second STA, wherein the second downlink interference amount is determined based on an indication of the second downlink interference amount included in the interference measurement feedback frame received from the second STA.

8. The method of claim 1, wherein the interference measurement feedback request frame is a beamforming report (BFRP) trigger frame or a variant thereof.

9. The method of claim 1, wherein the power control information frame further includes an indication of the first downlink transmit power.

10. The method of claim 1, wherein the interference measurement feedback frame is sent by the first STA in the distributed resource unit (dRU).

11. The method of claim 10, further comprising: Based on the received signal strength of the interference measurement feedback frame received from the first STA and the received signal strength of the second interference measurement feedback frame sent by the second STA, the first uplink interference amount at the shared AP and the second uplink interference amount at the shared AP are determined. Based on the first uplink interference and the second uplink interference, a first uplink transmit power to be used by the first STA and a second uplink transmit power to be used by the second STA are determined, wherein an indication of the second uplink transmit power is included in the power control information frame. The shared AP sends a first trigger frame to the first STA using the first downlink transmit power to request uplink transmission from the first STA, wherein the first trigger frame includes an indication of the first uplink transmit power; and the shared AP simultaneously sends a second trigger frame to the second STA using the second downlink transmit power to request uplink transmission from the second STA, wherein the second trigger frame includes an indication of the second uplink transmit power; and In response to the first trigger frame, a first uplink frame is received from the first STA, wherein the first STA transmits the first uplink frame to the shared AP in the dRU using the first uplink transmit power, wherein the second STA transmits a second uplink frame to the shared AP simultaneously using the second uplink transmit power, in response to the second trigger frame.

12. A method performed by a site STA for providing interference measurement feedback information to an access point AP, wherein the AP and the STA belong to a first BSS overlapping with a second basic service set BSS, the method comprising: Determine the amount of downlink interference caused by the second BSS at the STA; Receive an interference measurement feedback request frame from the AP for requesting interference measurement; and In response to receiving the interference measurement feedback request frame, an interference measurement feedback frame including an indication of the downlink interference amount at the STA is sent to the AP.

13. The method of claim 12, further comprising: The AP receives downlink frames, wherein the downlink frames are transmitted by the AP using downlink transmit power determined by the AP based on the downlink interference at the STA and the downlink interference caused by the first BSS at a second STA belonging to the second BSS, wherein the second AP belonging to the second BSS simultaneously transmits downlink frames to the second STA to achieve cooperative spatial multiplexing.

14. The method of claim 12, wherein the interference measurement feedback request frame is a beamforming report (BFRP) trigger frame or a variant thereof.

15. The method of claim 12, wherein the interference measurement feedback frame is transmitted in a distributed resource unit (dRU).

16. The method of claim 15, further comprising: Receive a trigger frame from the AP to request uplink transmission from the STA, wherein the trigger frame includes an indication of the uplink transmit power to be used by the STA; and In response to receiving the trigger frame, an uplink frame is transmitted from the dRU to the AP using the uplink transmit power.

17. The method of claim 12, further comprising: Receive a first measurement frame from the AP; Determine the received signal strength of the first measurement frame; Listen for the second measurement frame sent by the second AP belonging to the second BSS; and Determine the received signal strength of the second measurement frame. The downlink interference amount is determined based on the received signal strength of the first measurement frame and the received signal strength of the second measurement frame.

18. The method of claim 17, wherein the first measurement frame comprises a plurality of frames.

19. The method of claim 18, wherein the plurality of frames includes a Null Packet Announcement (NDPA) frame and a Null Packet Announcement (NDP) frame.

20. The method of claim 12, further comprising: Listen for measurement frames sent by the second AP belonging to the second BSS; and Determine the received signal strength of the measurement frame. The interference level is determined based on the received signal strength obtained through the beacon measurement request / report phase with the AP and the received signal strength of the measurement frame.

21. A method performed by a first access point (AP) for cooperating with a second AP to acquire channel information, wherein the first AP belongs to a first basic service set (BSS) and the second AP belongs to a second BSS, the method comprising: Send a multi-AP, M-AP trigger frame to the second AP to cause the second AP to send a measurement frame; Send a channel information feedback request frame to request the channel information from a station STA belonging to the first BSS; and In response to the channel information feedback request frame, a channel information feedback frame including the channel information is received from the STA, wherein the channel information is determined by the STA based on the measurement frame sent by the second AP.

22. The method of claim 21, wherein the measurement frame is an empty data packet (NDP) frame.

23. The method of claim 21, wherein the channel information feedback request frame is a beamforming report (BFRP) trigger frame or a variant thereof.

24. The method of claim 21, further comprising: A second measurement frame is sent simultaneously with the measurement frame sent by the second AP, wherein the channel information included in the channel information feedback frame is also determined by the STA based on the second measurement frame sent by the first AP.

25. The method of claim 24, wherein the channel information included in the channel information feedback frame includes information related to the amount of interference caused by the measurement frame transmitted by the second AP at the STA.

26. A method performed by a site STA for providing channel information to a first AP cooperating with a second access point AP, wherein the first AP and the STA belong to a first basic service set (BSS), and the second AP belongs to a second BSS, the method comprising: Receive measurement frames from the second AP belonging to the second BSS; The channel information is determined based on the measurement frame; Receive a channel information feedback request frame from the first AP for requesting the channel information; and In response to receiving the channel information feedback frame, a channel information feedback frame including the channel information is sent to the first AP.

27. The method of claim 26, wherein the measurement frame is an empty data packet (NDP) frame.

28. The method of claim 26, wherein the channel information feedback request frame is a beamforming report (BFRP) trigger frame or a variant thereof.

29. The method of claim 26, further comprising: Simultaneously with the measurement frame received from the second AP, a second measurement frame is received from the first AP, wherein the channel information is further determined based on the second measurement frame.

30. The method of claim 29, wherein the channel information includes information related to the amount of interference caused at the STA by the measurement frame received from the second AP.

31. A wireless device, comprising: Radio frequency transceiver; Memory stores instruction sets; and A processor coupled to the memory, wherein the instruction set, when executed by the processor, causes the wireless device to perform the method according to any one of claims 1 to 11.

32. A wireless device, comprising: Radio frequency transceiver; Memory stores instruction sets; and A processor coupled to the memory, wherein the instruction set, when executed by the processor, causes the wireless device to perform the method according to any one of claims 12 to 20.

33. A wireless device, comprising: Radio frequency transceiver; Memory stores instruction sets; and A processor coupled to the memory, wherein the instruction set, when executed by the processor, causes the wireless device to perform the method according to any one of claims 21 to 25.

34. A wireless device, comprising: Radio frequency transceiver; Memory stores instruction sets; and A processor coupled to the memory, wherein the instruction set, when executed by the processor, causes the wireless device to perform the method according to any one of claims 26 to 30.

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