Obtaining channel information for multi-access point coordination

Abstract

A method performed by a sharing access point (AP) to achieve coordinated spatial reuse 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 transmitting a multi-AP (M-AP) trigger frame to the shared AP, transmitting a first measurement frame to a first station (STA) that belongs to the first BSS, wherein the shared AP transmits a second measurement frame to a second STA that belongs to the second BSS responsive to receiving the M-AP trigger frame, transmitting an interference measurement feedback solicitation frame to the first STA, and receiving, as a response to the interference measurement feedback solicitation frame, an interference measurement feedback frame from the first STA that includes an indication of a first amount of downlink interference caused by the second measurement frame at the first STA.

Description

SPECIFICATIONOBTAINING CHANNEL INFORMATION FOR MULTI-ACCESS POINT COORDINATIONCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S. Provisional Application No. 63 / 619,691, filed January 10, 2024, titled “Interference measurement of Coordinated Spatial Reuse (C-SR) with Distributed Tone RU (dRU) beyond IEEE 802.1 Ibe”, which is hereby incorporated by reference.TECHNICAL FIELD

[0002] The present disclosure generally relates to wireless communications, and more specifically, relates to obtaining channel information for multi-access point coordination.BACKGROUND

[0003] Institute of Electrical and Electronics Engineers (IEEE) 802.11 is a set of standards for implementing wireless local area network communication in various frequencies, including but not limited to the 2.4 gigahertz (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, 802.1 In, 802.1 lac, and 802.1 lax (also known as “Wi-Fi 6”). These standards specify the modulation techniques, channel bandwidths, and other technical aspects that facilitate interoperability between devices from various manufacturers. IEEE 802.11 has played an important role in the widespread adoption of wireless networking in homes, offices, and public spaces, enabling users to connect their devices to the internet and each other without the need for wired connections.

[0004] IEEE 802.1 Ibe, 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, 802.1 Ibe aims to significantly improve upon the capabilities of its predecessor, 802.1 lax / Wi-Fi 6, by offering even higher data rates, lower latency, and increased reliability. The standard is expected to leverage advanced technologies such as multi-link operation (MLO), which allows devices to simultaneously use multiple frequency bands and channels for enhanced performance andreliability. Additionally, 802.11be will introduce 4096-QAM (Quadrature Amplitude Modulation), enabling higher data rates by encoding more bits per symbol. The standard will also feature improved medium access control (MAC) efficiency, enhanced power saving capabilities, and better support for high-density environments. With these advancements, 802.1 Ibe is expected to deliver theoretical maximum data rates 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 802.1 Ibe standard is projected to be finalized by the end of 2024, paving the way for the next generation of Wi-Fi devices and networks.

[0005] Coordinated spatial reuse (C-SR) and distributed tone resource unit (dRU) are technologies that can help improve spectral efficiency in wireless networks. C-SR can help improve spectral efficiency by allowing multiple devices to transmit simultaneously in the same frequency band without causing significant interference. During C-SR, two APs may simultaneously transmit downlink (DL) physical layer protocol data units (PPDUs) to stations (STA) or solicit simultaneous uplink (UL) PPDUs from STAs. To successfully achieve C-SR without interference between different basic service sets (BSSs), an “interference measurement phase” may initially be performed to determine the amount of interference between different BSSs. The interference measurement phase may include a downlink interference measurement phase and an uplink interference measurement phase. The transmit power to be used during C- SR for DL transmissions and / or UL transmissions may be determined based on the amount of interference between the different BSSs. The transmit power may be determined with the goal of reducing the amount of interference between the different BSSs to allow simultaneous transmission.

[0006] A dRU may be a resource unit that is composed of tones that are distributed across a spectrum (non-contiguous tones). dRU may help overcome the power spectral density (PSD) limitation. Various power modes are defined in 6 GHz bands such as standard power (SP) mode, very low power (VLP) mode, and low power indoor (LPI) mode. The PSD limitation is very tough especially in VLP mode and LPI mode in 6 GHz bands and especially for non-AP STAs. For example, the PSD limitation of a non-AP STA in LPI mode is -1 dBM / MHz. As a result, using many resource unit (RU) tones in a limited bandwidth can decrease transmit power due to the tough PSD limitation.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The disclosure will be more fully understood from the detailed description provided below and the accompanying drawings that depict various embodiments of the disclosure. However, these drawings should not be interpreted as limiting the disclosure to the specific embodiments shown; they are provided for explanation and understanding only.

[0008] Figure 1 illustrates an example of a wireless local area network (WLAN) with a basic service set (BSS) that includes multiple wireless devices, in accordance with some embodiments of the present disclosure.

[0009] Figure 2 is a schematic diagram of a wireless device, in accordance with some embodiments of the present disclosure.

[0010] Figure 3 A illustrates components of a wireless device configured to transmit data, in accordance with some embodiments of the present disclosure.

[0011] Figure 3B illustrates components of a wireless device configured to receive data, in accordance with some embodiments of the present disclosure.

[0012] Figure 4 illustrates interframe space (IFS) relationships, in accordance with some embodiments of the present disclosure.

[0013] Figure 5 illustrates a Carrier Sense Multiple Access with Collision Avoidance (CSMA / CA)-based frame transmission procedure, in accordance with some embodiments of the present disclosure.

[0014] Figure 6 illustrates maximum physical layer (PHY) rates for Institute of Electrical and Electronics Engineers (IEEE) 802.11 standards, in accordance with some embodiments of the present disclosure.

[0015] Figure 7 provides a detailed description of fields in Extremely High Throughput (EHT) Physical Protocol Data Unit (PPDU) frames, including their purposes and characteristics, in accordance with some embodiments of the present disclosure.

[0016] Figure 8 illustrates an example of multi-user (MU) transmission in Orthogonal Frequency -Di vision Multiple Access (OFDMA), in accordance with some embodiments of the present disclosure.

[0017] Figure 9 illustrates an example of an access point sending a trigger frame to multiple associated stations and receiving Uplink Orthogonal Frequency -Division Multiple Access Trigger-Based Physical Protocol Data Units (UL OFDMA TB PPDUs) in response, in accordance with some embodiments of the present disclosure.

[0018] Figure 10 is a diagram showing two main phases of a coordinated spatial reuse (C-SR) procedure, according to some embodiments.

[0019] Figure 11 is a diagram showing a communication sequence for an interference measurement phase (for option 1), according to some embodiments.

[0020] Figure 12 is a diagram showing a communication sequence for an interference measurement phase (for option 2), according to some embodiments.

[0021] Figure 13 is a diagram showing uplink interference in a wireless network during C-SR, according to some embodiments.

[0022] Figure 14 is a diagram showing a communication sequence for an interference measurement phase that allows for determining the amount of uplink interference for a dRU, according to some embodiments.

[0023] Figure 15 is a flow diagram of a method for achieving C-SR in the downlink direction, according to some embodiments.

[0024] Figure 16 is a flow diagram of a method for achieving C-SR in the uplink direction, according to some embodiments.

[0025] Figure 17 is a flow diagram of a method for providing downlink interference measurement feedback information, according to some embodiments.

[0026] Figure 18 is a flow diagram of a method for obtaining channel information, according to some embodiments.

[0027] Figure 19 is a flow diagram of a method for providing channel information, according to some embodiments.DETAILED DESCRIPTION

[0028] The present disclosure generally relates to wireless communications, and more specifically, relates to obtaining channel information for multi -access point (multi-AP) coordination.

[0029] Coordinated spatial reuse (C-SR) is a type of multi-AP coordination scheme that can help improve spectral efficiency. To successfully achieve C-SR, it is important to control the transmit power of the devices participating in C-SR to reduce interference. Techniques are described herein that allow stations (STAs) to provide information regarding the amount of downlink interference at the STAs to an access point (AP) so that the AP can determine the appropriate transmit power that multiple APs should use for downlink transmissions to the STAs to achieve C-SR. Also, techniques are described herein that allow the AP to determine the amount of uplink interference at the AP so that the AP can determine the appropriate transmit power that STAs should use for uplink transmissions to the AP to achieve C-SR. In an embodiment, a STA provides information regarding the amount of downlink interference at theSTA to the AP in a frame that is referred to herein as an interference measurement feedback frame. In an embodiment, the STA transmits the interference measurement feedback frame to the AP in a distributed tone resource unit (dRU), which allows the AP to determine the amount of uplink interference at the AP for the dRU without additional overhead (e.g., without having to transmit / exchange additional frames).

[0030] According to some embodiments, a sharing AP that belongs to a first basic service set (BSS) may transmit a multi-AP trigger frame to a shared AP that belongs to a second BSS. After transmitting the multi-AP trigger frame, the sharing AP may transmit a first measurement frame to a first STA that belongs to the first BSS. Responsive to receiving the M-AP trigger frame from the sharing AP, the shared AP may transmit a second measurement frame to a second STA that belongs to the second BSS. The sharing AP’s transmission of the first measurement frame and the shared AP’s transmission of the second measurement frame may occur simultaneously. The first STA may determine a first amount of interference caused by the second BSS at the first STA based on the received signal strengths of the first measurement frame and the second measurement frame. Similarly, the second STA may determine a second amount of interference caused by the first BSS at the second STA based on the received signal strengths of the first measurement frame and the second measurement frame. The sharing AP may transmit an interference measurement feedback solicitation frame to the first STA and second STA that solicits interference measurements from the first STA and the second STA.Responsive to receiving the interference measurement feedback solicitation frame, the first STA may transmit a first interference measurement feedback frame to the sharing AP that includes an indication of the first amount of downlink interference caused by the second BSS at the first STA. Similarly, responsive to receiving the interference measurement feedback solicitation frame, the second STA may transmit a second interference measurement feedback frame to the sharing AP that includes an indication of the second amount of downlink interference caused by the first BSS at the second STA.

[0031] The sharing AP may determine a first downlink transmit power to be used by the sharing AP and a second downlink transmit power to be used by the shared AP based on the first amount of downlink interference and the second amount of downlink interference. The sharing AP may transmit a power control information frame to the shared AP that includes an indication of the second downlink transmit power. The sharing AP may then transmit a first downlink frame to the first STA using the first downlink transmit power. The shared AP may transmit a second downlink frame to the second STA using the second downlink transmit power indicated in the power control information frame. The sharing AP’s transmission of the first downlinkframe and the shared AP’s transmission of the second downlink frame may occur simultaneously to achieve C-SR in the downlink direction.

[0032] In an embodiment, the first STA and the second STA transmit the first interference measurement feedback frame and the second interference measurement feedback frame, respectively, to the sharing AP in a dRU. The sharing AP may determine a first amount of uplink interference caused by the second BSS at the sharing AP and a second amount of uplink interference caused by the first BSS at the shared AP based on received signal strengths of the first interference measurement feedback frame received from the first STA and the second interference measurement feedback frame received from second STA. Transmitting the interference measurement feedback frames in the dRU allows the sharing AP to determine the amount of uplink interference at the sharing AP for the dRU and / or the amount of uplink interference at the shared AP for the dRU without additional overhead (e.g., without having to transmit / exchange additional frames).

[0033] The sharing AP may determine a first uplink transmit power that is to be used by the first STA and a second uplink transmit power that is to be used by the second STA based on the first amount of uplink interference and the second amount of uplink interference. The sharing AP may include an indication of the second uplink transmit power in the power control information frame that it transmits to the shared AP (thus, the power control information frame may include an indication of the second downlink transmit power and the second uplink transmit power). The sharing AP may transmit a first trigger frame to the first STA using the first downlink transmit power that solicits an uplink transmission from the first STA, wherein the first trigger frame includes an indication of the first uplink transmit power. The shared AP may simultaneously transmit a second trigger frame to the second STA using the second downlink transmit power that solicits an uplink transmission from the second STA, wherein the second trigger frame includes an indication of the second uplink transmit power. The sharing AP’s transmission of the first trigger frame and the shared AP’s transmission of the second trigger frame may occur simultaneously to achieve C-SR in the downlink direction. Responsive to receiving the first trigger frame, the first STA may transmit a first uplink frame to the sharing AP in the dRU using the first uplink transmit power. Also, responsive to receiving the second trigger frame, the second STA may transmit a second uplink frame to the shared AP in the dRU using the second uplink transmit power. The first STA’s transmission of the first uplink frame and the second STA’s transmission of the second uplink frame may occur simultaneously to achieve C-SR in the uplink direction.

[0034] For purposes of illustration, various embodiments are described herein in the context of wireless networks that are based on IEEE 802.11 standards and using terminology and concepts thereof. Those skilled in the art will appreciate that the embodiments disclosed herein can be modified / adapted for use in other types of wireless networks.

[0035] In the following detailed description, only certain embodiments of the present invention have been shown and described, simply by way of illustration. As those skilled in the art would realize, the described embodiments may be modified in different ways, all without departing from the spirit or scope of the present invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not restrictive. Like reference numerals designate like elements throughout the specification.

[0036] Figure 1 shows a wireless local area network (WLAN) 100 with a basic service set (BSS) 102 that includes a plurality of wireless devices 104 (sometimes referred to as WLAN devices 104). Each of the wireless devices 104 may include a medium access control (MAC) layer and a physical (PHY) layer according to an IEEE (Institute of Electrical and Electronics Engineers) standard 802.11, including one or more of the amendments(e.g., 802.1 la / b / g / n / p / ac / ax / bd / be). In one embodiment, the MAC layer of a wireless device 104 may initiate 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 a corresponding frame. Similarly, a PHY layer of a receiving wireless device may generate an RXVECTOR, which includes parameters of a received frame and is passed to a MAC layer for processing.

[0037] The plurality of wireless devices 104 may include a wireless device 104A that is an access point (sometimes referred to as an AP station or AP STA) and the other wireless devices 104B1-104B4 that are non-AP stations (sometimes referred to as non-AP STAs). Alternatively, all the plurality of wireless devices 104 may be non-AP STAs in an ad-hoc networking environment. In general, the AP STA (e.g., wireless device 104 A) and the non-AP STAs (e.g., wireless devices 104B1-104B4) may be collectively referred to as STAs. However, for ease of description, only the non-AP STAs may be referred to as STAs unless the context indicates otherwise. Although shown with four non-AP STAs (e.g., the wireless devices 104B1- IO4B4), the WLAN 100 may include any number of non-AP STAs (e.g., one or more wireless devices 104B).

[0038] Figure 2 illustrates a schematic block diagram of a wireless device 104, according to an embodiment. The wireless device 104 may be the wireless device 104 A (i.e., the AP of the WLAN 100) or any of the wireless devices 104B1-104B4 in Figure 1. The wireless device 104includes a baseband processor 210, a radio frequency (RF) transceiver 240, an antenna unit 250, a storage device (e.g., memory device) 232, one or more input interfaces 234, and one or more output interfaces 236. The baseband processor 210, the storage device 232, the input interfaces 234, the output interfaces 236, and the RF transceiver 240 may communicate with each other via a bus 260.

[0039] 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 the memory 232, which may include a non-transitory computer / machine readable medium having software (e.g., computer / machine programing instructions) and data stored therein.

[0040] In an 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 may implement a first plurality of functions of the MAC layer by executing MAC software, which may be included in the software stored in the storage device 232. The MAC hardware processing unit 216 may implement a second plurality of functions of the MAC layer in specialpurpose hardware. However, the MAC processor 212 is not limited thereto. For example, the MAC processor 212 may be configured to perform the first and second plurality of functions entirely in software or entirely in hardware according to an implementation.

[0041] The PHY processor 222 includes a transmitting (TX) signal processing unit (SPU) 224 and a receiving (RX) SPU 226. The PHY processor 222 implements a plurality of functions of the PHY layer. These functions may be performed in software, hardware, or a combination thereof according to an implementation.

[0042] Functions performed by the transmitting SPU 224 may include one or more of Forward Error Correction (FEC) encoding, stream parsing into one or more spatial streams, diversity encoding of the spatial streams into a plurality of space-time streams, spatial mapping of the space-time streams to transmit chains, inverse Fourier Transform (iFT) computation, Cyclic Prefix (CP) insertion to create a Guard Interval (GI), and the like. Functions performed by the receiving SPU 226 may include inverses of the functions performed by the transmitting SPU 224, such as GI removal, Fourier Transform computation, and the like.

[0043] The RF transceiver 240 includes an RF transmitter 242 and an RF receiver 244. The RF transceiver 240 is configured to transmit first information received from the baseband processor 210 to the WLAN 100 (e.g., to another WLAN device 104 of the WLAN 100) and provide second information received from the WLAN 100 (e.g., from another WLAN device 104 of the WLAN 100) to the baseband processor 210.

[0044] The antenna unit 250 includes one or more antennas. When Multiple-Input Multiple- Output (MIMO) or Multi-User MIMO (MU-MIMO) is used, the antenna unit 250 may include a plurality of antennas. In an embodiment, the antennas in the antenna unit 250 may operate as a beam-formed antenna array. In an embodiment, the antennas in the antenna unit 250 may be directional antennas, which may be fixed or steerable.

[0045] The input interfaces 234 receive information from a user, and the output interfaces 236 output information to the user. The input interfaces 234 may include one or more of a keyboard, keypad, mouse, touchscreen, microphone, and the like. The output interfaces 236 may include one or more of a display device, touch screen, speaker, and the like.

[0046] As described herein, many functions of the WLAN device 104 may be implemented in either hardware or software. Which functions are implemented in software and which functions are implemented in hardware will vary according to constraints imposed on a design. The constraints may include one or more of design cost, manufacturing cost, time to market, power consumption, available semiconductor technology, etc.

[0047] As described herein, a wide variety of electronic devices, circuits, firmware, software, and combinations thereof may be used to implement the functions of the components of the WLAN device 104. Furthermore, the WLAN device 104 may include other components, such as application processors, storage interfaces, clock generator circuits, power supply circuits, and the like, which have been omitted in the interest of brevity.

[0048] Figure 3 A illustrates components of a WLAN device 104 configured to transmit data according to an embodiment, including a transmitting (Tx) SPU (TxSP) 324, an RF transmitter 342, and an antenna 352. In an embodiment, the TxSP 324, the RF transmitter 342, and the antenna 352 correspond to the transmitting SPU 224, the RF transmitter 242, and an antenna of the antenna unit 250 of Figure 2, respectively.

[0049] The TxSP 324 includes an encoder 300, an interleaver 302, a mapper 304, an inverse Fourier transformer (TFT) 306, and a guard interval (GI) inserter 308.

[0050] The encoder 300 receives and encodes input data. In an embodiment, the encoder 300 includes a forward error correction (FEC) encoder. The FEC encoder may include a binary convolution code (BCC) encoder followed by a puncturing device. The FEC encoder may include a low-density parity-check (LDPC) encoder.

[0051] The TxSP 324 may further include a scrambler for scrambling the input data before the encoding is performed by the encoder 300 to reduce the probability of long sequences of 0s or Is. When the encoder 300 performs the BCC encoding, the TxSP 324 may further include anencoder parser for demultiplexing the scrambled bits among a plurality of BCC encoders. If LDPC encoding is used in the encoder, the TxSP 324 may not use the encoder parser.

[0052] The interleaver 302 interleaves the bits of each stream output from the encoder 300 to change an order of bits therein. The interleaver 302 may apply the interleaving only when the encoder 300 performs BCC encoding and otherwise may output the stream output from the encoder 300 without changing the order of the bits therein.

[0053] The mapper 304 maps the sequence of bits output from the interleaver 302 to constellation points. If the encoder 300 performed LDPC encoding, the mapper 304 may also perform LDPC tone mapping in addition to constellation mapping.

[0054] When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324 may include a plurality of interleavers 302 and a plurality of mappers 304 according to a number of spatial streams (NSS) of the transmission. The TxSP 324 may further include a stream parser for dividing the output of the encoder 300 into blocks and may respectively send the blocks to different interleavers 302 or mappers 304. The TxSP 324 may further include a space-time block code (STBC) encoder for spreading the constellation points from the spatial streams into a number of space-time streams (NSTS) and a spatial mapper for mapping the space-time streams to transmit chains. The spatial mapper may use direct mapping, spatial expansion, or beamforming.

[0055] The IFT 306 converts a block of the constellation points output from the mapper 304 (or, when MIMO or MU-MIMO is performed, the spatial mapper) to a time domain block (i.e., a symbol) by using an inverse discrete Fourier transform (IDFT) or an inverse fast Fourier transform (IFFT). If the STBC encoder and the spatial mapper are used, the IFT 306 may be provided for each transmit chain.

[0056] When the TxSP 324 performs a MIMO or MU-MIMO transmission, the TxSP 324 may insert cyclic shift diversities (CSDs) to prevent unintentional beamforming. The TxSP 324 may perform the insertion of the CSD before or after the IFT 306. The CSD may be specified per transmit chain or may be specified per space-time stream. Alternatively, the CSD may be applied as a part of the spatial mapper.

[0057] When the TxSP 324 performs a MIMO or MU-MIMO transmission, some blocks before the spatial mapper may be provided for each user.

[0058] The GI inserter 308 prepends a GI to each symbol produced by the IFT 306. Each GI may include a Cyclic Prefix (CP) corresponding to a repeated portion of the end of the symbol that the GI precedes. The TxSP 324 may optionally perform windowing to smooth edges of each symbol after inserting the GI.

[0059] The RF transmitter 342 converts the symbols into an RF signal and transmits the RF signal via the antenna 352. When the TxSP 324 performs a MIMO or MU-MIMO transmission, the GI inserter 308 and the RF transmitter 342 may be provided for each transmit chain.

[0060] Figure 3B illustrates components of a WLAN device 104 configured to receive data according to an embodiment, including a Receiver (Rx) SPU (RxSP) 326, an RF receiver 344, and an antenna 354. In an embodiment, the RxSP 326, RF receiver 344, and antenna 354 may correspond to the receiving SPU 226, the RF receiver 244, and an antenna of the antenna unit 250 of Figure 2, respectively.

[0061] The RxSP 326 includes a GI remover 318, a Fourier transformer (FT) 316, a demapper 314, a deinterleaver 312, and a decoder 310.

[0062] The RF receiver 344 receives an RF signal via the antenna 354 and converts the RF signal into symbols. The GI remover 318 removes the GI from each of the symbols. When the received transmission is a MIMO or MU-MIMO transmission, the RF receiver 344 and the GI remover 318 may be provided for each receive chain.

[0063] The FT 316 converts each symbol (that is, each time domain block) into a frequency domain block of constellation points by using a discrete Fourier transform (DFT) or a fast Fourier transform (FFT). The FT 316 may be provided for each receive chain.

[0064] When the received transmission is the MIMO or MU-MIMO transmission, the RxSP 326 may include a spatial demapper for converting the respective outputs of the FTs 316 of the receiver chains to constellation points of a plurality of space-time streams, and an STBC decoder for despreading the constellation points from the space-time streams into one or more spatial streams.

[0065] The demapper 314 demaps the constellation points output from the FT 316 or the STBC decoder to bit streams. If the received transmission was encoded using LDPC encoding, the demapper 314 may further perform LDPC tone demapping before performing the constellation demapping.

[0066] The deinterleaver 312 deinterleaves the bits of each stream output from the demapper 314. The deinterleaver 312 may perform the deinterleaving only when the received transmission was encoded using BCC encoding, and otherwise may output the stream output by the demapper 314 without performing deinterleaving.

[0067] When the received transmission is the MIMO or MU-MIMO transmission, the RxSP 326 may use a plurality of demappers 314 and a plurality of deinterleavers 312 corresponding to the number of spatial streams of the transmission. In this case, the RxSP 326may further include a stream deparser for combining the streams output from the deinterleavers 312.

[0068] The decoder 310 decodes the streams output from the deinterleaver 312 or the stream deparser. In an embodiment, the decoder 310 includes an FEC decoder. The FEC decoder may include a BCC decoder or an LDPC decoder.

[0069] The RxSP 326 may further include a descrambler for descrambling the decoded data. When the decoder 310 performs BCC decoding, the RxSP 326 may further include an encoder deparser for multiplexing the data decoded by a plurality of BCC decoders. When the decoder 310 performs the LDPC decoding, the RxSP 326 may not use the encoder deparser.

[0070] Before making a transmission, wireless devices such as wireless device 104 will assess the availability of the wireless medium using Clear Channel Assessment (CCA). If the medium is occupied, CCA may determine that it is busy, while if the medium is available, CCA determines that it is idle.

[0071] The PHY entity for IEEE 802.11 is based on Orthogonal Frequency Division Multiplexing (OFDM) or Orthogonal Frequency Division Multiple Access (OFDMA). In either OFDM or OFDMA Physical (PHY) layers, a STA (e.g., a wireless device 104) is capable of transmitting and receiving Physical Layer (PHY) Protocol Data Units (PPDUs) (also referred to as PLCP (Physical Layer Convergence Procedure) Protocol Data Units) that are compliant with the mandatory PHY specifications. A PHY specification defines a set of Modulation and Coding Schemes (MCS) and a maximum number of spatial streams. Some PHY entities define downlink (DL) and uplink (UL) Multi-User (MU) transmissions having a maximum number of space-time streams (STS) per user and employing up to a predetermined total number of STSs. A PHY entity may provide support for 10 Megahertz (MHz), 20 MHz, 40 MHz, 80 MHz, 160 MHz, 240 MHz, and 320 MHz contiguous channel widths and support for an 80+80, 80+160 MHz, and 160+160 MHz non-contiguous channel width. Each channel includes a plurality of subcarriers, which may also be referred to as tones. A PHY entity may define signaling fields denoted as Legacy Signal (L-SIG), Signal A (SIG-A), and Signal B (SIG-B), and the like within a PPDU by which some necessary information about PHY Service Data Unit (PSDU) attributes are communicated. The descriptions below, for sake of completeness and brevity, refer to OFDM-based 802.11 technology. Unless otherwise indicated, a station refers to a non-AP STA.

[0072] Figure 4 illustrates Inter-Frame Space (IFS) relationships. In particular, Figure 4 illustrates a Short IFS (SIFS), a Point Coordination Function (PCF) IFS (PIFS), a Distributed Coordination Function (DCF) IFS (DIFS), and an Arbitration IFSs corresponding to an Access Category (AC) ‘i’ (AIFS[i]). Figure 4 also illustrates a slot time and a data frame is used fortransmission of data forwarded to a higher layer. As shown, a WLAN device 104 transmits the data frame after performing backoff if a DIFS has elapsed during which the medium has been idle.

[0073] A management frame may be used for exchanging management information, which is not forwarded to the higher layer. Subtype frames of the management frame include a beacon frame, an association request / response frame, a probe request / response frame, and an authentication request / response frame.

[0074] A control frame may be used for controlling access to the medium. Subtype frames of the control frame include a request to send (RTS) frame, a clear to send (CTS) frame, and an acknowledgement (ACK) frame.

[0075] When the control frame is not a response frame of another frame, the WLAN device 104 transmits the control frame after performing backoff if a DIFS has elapsed during which the medium has been idle. When the control frame is the response frame of another frame, the WLAN device 104 transmits the control frame after a SIFS has elapsed without performing backoff or checking whether the medium is idle.

[0076] A WLAN device 104 that supports Quality of Service (QoS) functionality (that is, a QoS STA) may transmit the frame after performing backoff if an AIFS for an associated access category (AC) (i.e., AIFS[AC]) has elapsed. When transmitted by the QoS STA, any of the data frame, the management frame, and the control frame, which is not the response frame, may use the AIFS[AC] of the AC of the transmitted frame.

[0077] A WLAN device 104 may perform a backoff procedure when the WLAN device 104 that is ready to transfer a frame finds the medium busy. The backoff procedure includes determining a random backoff time composed of N backoff slots, where each backoff slot has a duration equal to a slot time and N being an integer number greater than or equal to zero. The backoff time may be determined according to a length of a Contention Window (CW). In an embodiment, the backoff time may be determined according to an AC of the frame. All backoff slots occur following a DIFS or Extended IFS (EIFS) period during which the medium is determined to be idle for the duration of the period.

[0078] When the WLAN device 104 detects no medium activity for the duration of a particular backoff slot, the backoff procedure shall decrement the backoff time by the slot time. When the WLAN device 104 determines that the medium is busy during a backoff slot, the backoff procedure is suspended until the medium is again determined to be idle for the duration of a DIFS or EIFS period. The WLAN device 104 may perform transmission or retransmission of the frame when the backoff timer reaches zero.

[0079] The backoff procedure operates so that when multiple WLAN devices 104 are deferring and execute the backoff procedure, each WLAN device 104 may select a backoff time using a random function and the WLAN device 104 that selects the smallest backoff time may win the contention, reducing the probability of a collision.

[0080] Figure 5 illustrates a Carrier Sense Multiple Access / Collision Avoidance (CSMA / CA) based frame transmission procedure for avoiding collision between frames in a channel according to an embodiment. Figure 5 shows a first station STA1 transmitting data, a second station STA2 receiving the data, and a third station STA3 that may be located in an area where a frame transmitted from the STA1 can be received, a frame transmitted from the second station STA2 can be received, or both can be received. The stations STA1, STA2, and STA3 may be WLAN devices 104 of Figure 1.

[0081] The station STA1 may determine whether the channel is busy by carrier sensing. The station STA1 may determine channel occupation / status based on an energy level in the channel or an autocorrelation of signals in the channel, or may determine the channel occupation by using a network allocation vector (NAV) timer.

[0082] After determining that the channel is not used by other devices (that is, that the channel is IDLE) during a DIFS (and performing backoff if required), the station STA1 may transmit a Request-To-Send (RTS) frame to the station STA2. Upon receiving the RTS frame, after a SIFS the station STA2 may transmit a Clear-To-Send (CTS) frame as a response to the RTS frame. If Dual-CTS is enabled and the station STA2 is an AP, the AP may send two CTS frames in response to the RTS frame (e.g., a first CTS frame in a non-High Throughput format and a second CTS frame in the HT format).

[0083] When the station STA3 receives the RTS frame, it may set a NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames (for example, a duration of SIFS + CTS frame duration + SIFS + data frame duration + SIFS + ACK frame duration) using duration information included in the RTS frame. When the station STA3 receives the CTS frame, it may set the NAV timer of the station STA3 for a transmission duration of subsequently transmitted frames using duration information included in the CTS frame. Upon receiving a new frame before the NAV timer expires, the station STA3 may update the NAV timer of the station STA3 by using duration information included in the new frame. The station STA3 does not attempt to access the channel until the NAV timer expires.

[0084] When the station STA1 receives the CTS frame from the station STA2, it may transmit a data frame to the station STA2 after a SIFS period elapses from a time when the CTS framehas been completely received. Upon successfully receiving the data frame, the station STA2 may transmit an ACK frame as a response to the data frame after a SIFS period elapses.

[0085] When the NAV timer expires, the third station STA3 may determine whether the channel is busy using the carrier sensing. Upon determining that the channel is not used by other devices during a DIFS period after the NAV timer has expired, the station STA3 may attempt to access the channel after a contention window elapses according to a backoff process.

[0086] When Dual-CTS is enabled, a station that has obtained a transmission opportunity (TXOP) and that has no data to transmit may transmit a CF-End frame to cut short the TXOP. An AP receiving a CF-End frame having a Basic Service Set Identifier (BSSID) of the AP as a destination address may respond by transmitting two more CF-End frames: a first CF-End frame using Space Time Block Coding (STBC) and a second CF-End frame using non-STBC. A station receiving a CF-End frame resets its NAV timer to 0 at the end of the PPDU containing the CF-End frame. Figure 5 shows the station STA2 transmitting an ACK frame to acknowledge the successful reception of a frame by the recipient.

[0087] The IEEE 802.1 Ibn (Ultra High Reliability, UHR) working group has been established to address the growing demand for higher peak throughput and reliability in Wi-Fi. As shown in Figure 6, the peak PHY rate has significantly increased from IEEE 802.1 lb to IEEE 802.1 Ibe (Wi-Fi 7), with the latter focusing on further improving peak throughput. The UHR study group aims to enhance the tail of the latency distribution and jitter to support applications that require low latency, such as video-over- WLAN, gaming, AR, and VR. It is noted that various characteristics of UHR (e.g., max PHY rate, PHY rate enhancement, bandwidth / number of spatial streams, and operating bands) are still to be determined.

[0088] The focus of IEEE 802.1 Ibe is primarily on WLAN indoor and outdoor operation with stationary and pedestrian speeds in the 2.4, 5, and 6 GHz frequency bands. In addition to peak PHY rate, different candidate features are under discussion. These candidate features include (1) a 320MHz bandwidth and a more efficient utilization of a non-contiguous spectrum, (2) multi -band / multi-channel aggregation and operation, (3) 16 spatial streams and Multiple Input Multiple Output (MIMO) protocol enhancements, (4) multi-Access Point (AP) Coordination (e.g., coordinated and joint transmission), (5) an enhanced link adaptation and retransmission protocol (e.g., Hybrid Automatic Repeat Request (HARQ)), and (6) adaptation to regulatory rules specific to a 6 GHz spectrum.

[0089] The focus of IEEE 802.1 Ibn (UHR) is still under discussion, with candidate features including MLO enhancements (e.g., in terms of increased throughput / reliability and decreased latency), latency and reliability improvements (e.g., multi-AP coordination to support lowlatency traffic), bandwidth expansion (e.g., to 240, 480, 640 MHz), aggregated PPDU (A- PPDU), enhanced multi-link single-radio (eMLSR) extensions to AP, roaming improvements, and power-saving schemes for prolonging battery life.

[0090] Some features, such as increasing the bandwidth and the number of spatial streams, are solutions that have been proven to be effective in previous projects focused on increasing link throughput and on which feasibility demonstration is achievable.

[0091] With respect to operational bands (e.g., 2.4 / 5 / 6 GHz) for IEEE 802.1 Ibe, more than 1 GHz of additional unlicensed spectrum is likely to be available because the 6 GHz band(5.925- 7.125 GHz) is being considered for unlicensed use. This would allow APs and STAs to become tri-band devices. Larger than 160MHz data transmissions (e.g., 320 MHz or 640 MHz) could be considered to increase the maximum PHY rate. For example, 320 MHz or 160+160MHz data could be transmitted in the 6 GHz band. For example, 160+160 MHz data could be transmitted across the 5 and 6 GHz bands.

[0092] In the process of wireless communication, a transmitting station (STA) creates a Physical Layer Protocol Data Unit (PPDU) frame and sends it to a receiving STA. The receiving STA then receives, detects, and processes the PPDU.

[0093] The Extremely High Throughput (EHT) PPDU frame encompasses several components. It includes a legacy part, which comprises 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.

[0094] In addition to the legacy part, the EHT PPDU frame also contains the Universal Signal Field (U-SIG), EHT Signal Field (EHT-SIG), EHT Short Training Field (EHT-STF), and 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.

[0095] Figure 7 provides a more detailed description of each field in the EHT PPDU frame, including their purposes and characteristics.

[0096] Regarding the Ultra High Reliability (UHR) PPDU, its frame structure is currently undefined and will be determined through further discussions within the relevant working group or study group. This indicates that the specifics of the UHR PPDU are still under development and will be finalized based on the outcomes of future deliberations.

[0097] The distributed nature of channel access networks, such as IEEE 802.11 WLANs, makes the carrier sense mechanism useful for ensuring collision-free operation. Each station (STA) uses its physical carrier sense to detect transmissions from other STAs. However, incertain situations, it may not be possible for a STA to detect every transmission. For instance, when one STA is located far away from another STA, it might perceive the medium as idle and start transmitting a frame, leading to collisions. To mitigate this hidden node problem, the network allocation vector (NAV) has been introduced.

[0098] As the IEEE 802.11 standard continues to evolve, it now includes scenarios where multiple users can simultaneously transmit or receive data within a basic service set (BSS), such as uplink (UL) and downlink (DL) multi-user (MU) transmissions in a cascaded manner. In these cases, the existing carrier sense and NAV mechanisms may not be sufficient, and modifications or newly defined mechanisms may be required to facilitate efficient and collision- free operation.

[0099] For the purpose of this disclosure, MU transmission refers to situations where multiple frames are transmitted to or from multiple STAs simultaneously using different resources. Examples of these resources include different frequency resources in Orthogonal Frequency Division Multiple Access (OFDMA) transmission and different spatial streams in Multi-User Multiple Input Multiple Output (MU-MIMO) transmission. Consequently, 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 transmission.

[0100] Figure 8 illustrates an example of multi-user (MU) transmission in Orthogonal Frequency -Division Multiple Access (OFDMA), in accordance with some embodiments of the present disclosure.

[0101] In the IEEE 802.1 lax and 802.1 Ibe specifications, the trigger frame plays a useful role in facilitating uplink multi-user (MU) transmissions. The purpose of the trigger frame is to allocate resources and solicit one or more Trigger-based (TB) Physical Layer Protocol Data Unit (PPDU) transmissions from the associated stations (STAs).

[0102] The trigger frame contains information required by the responding STAs to send their Uplink TB PPDUs. This information includes the Trigger type, which specifies the type of TB PPDU expected, and the Uplink Length (UL Length), which indicates the duration of the uplink transmission.

[0103] Figure 9 illustrates an example scenario where an access point (AP) operating in an 80MHz bandwidth environment sends a Trigger frame to multiple associated STAs. Upon receiving the Trigger frame, the STAs respond by sending their respective Uplink Orthogonal Frequency Division Multiple Access (UL OFDMA) TB PPDUs, utilizing the allocated resources within the specified 80 MHz bandwidth.

[0104] After successfully receiving the UL OFDMA TB PPDUs, the AP acknowledges the STAs by sending an acknowledgement frame. This acknowledgement can be in the form of an 80MHz width multi-STA Block Acknowledgement (Block Ack) or a Block Acknowledgement with a Direct Feedback (DF) OFDMA method. The multi-STA Block Ack allows the AP to acknowledge multiple STAs simultaneously, while the Block Ack with DF OFDMA enables the AP to provide feedback to the STAs using the same OFDMA technique employed in the uplink transmission.

[0105] The trigger frame is a useful component in enabling efficient uplink MU transmissions in IEEE 802.1 lax and 802.1 Ibe networks, by allocating resources and coordinating the uplink transmissions from multiple STAs within the same bandwidth.

[0106] Wireless network systems can rely on retransmission of media access control (MAC) protocol data units (MPDUs) when the transmitter (TX) does not receive an acknowledgement from the receiver (RX) or MPDUs are not successfully decoded by the receiver. Using an automatic repeat request (ARQ) approach, the receiver discards the last failed MPDU before receiving the newly retransmitted MPDU. With requirements of enhanced reliability and reduced latency, the wireless network system can evolve toward a hybrid ARQ (HARQ) approach.

[0107] There are two methods of HARQ processing. In a first type of HARQ scheme, also referred to as chase combining (CC) HARQ (CC-HARQ) scheme, signals to be retransmitted are the same as the signals that previously failed because all subpackets to be retransmitted use the same puncturing pattern. The puncturing is needed to remove some of the parity bits after encoding using an error-correction code. The reason why the same puncturing pattern is used with CC-HARQ is to generate a coded data sequence with forward error correction (FEC) and to make the receiver use a maximum-ratio combining (MRC) to combine the received, retransmitted bits with the same bits from the previous transmission. For example, information sequences are transmitted in packets with a fixed length. At a receiver, error correction and detection are carried out over the whole packet. However, the ARQ scheme may be inefficient in the presence of burst errors. To solve this more efficiently, subpackets are used. In subpacket transmissions, only those subpackets that include errors need to be retransmitted.

[0108] Since the receiver uses both the current and the previously received subpackets for decoding data, the error probability in decoding decreases as the number of used subpackets increases. The decoding process passes a cyclic redundancy check (CRC) and ends when the entire packet is decoded without error or the maximum number of subpackets is reached. In particular, this scheme operates on a stop-and-wait protocol such that if the receiver can decodethe packet, it sends an acknowledgement (ACK) to the transmitter. When the transmitter receives an ACK successfully, it terminates the HARQ transmission of the packet. If the receiver cannot decode the packet, it sends a negative acknowledgement (NAK) to the transmitter and the transmitter performs the retransmission process.

[0109] In a second type of HARQ scheme, also referred to as an incremental redundancy (IR) HARQ (IR-HARQ) scheme, different puncturing patterns are used for each subpacket such that the signal changes for each retransmitted subpacket in comparison to the originally transmitted subpacket. IR-HARQ alternatively uses two puncturing patterns for odd numbered and even numbered transmissions, respectively. The redundancy scheme of IR-HARQ improves the log likelihood ratio (LLR) of parity bit(s) in order to combine information sent across different transmissions due to requests and lowers the code rate as the additional subpacket is used. This results in a lower error rate of the subpacket in comparison to CC-HARQ. The puncturing pattern used in IR-HARQ is indicated by a subpacket identity (SPID) indication. The SPID of the first subpacket may always be set to 0 and all the systematic bits and the punctured parity bits are transmitted in the first subpacket. Self-decoding is possible when the receiving signal- to-noise ratio (SNR) environment is good (i.e., a high SNR). In some embodiments, subpackets with corresponding SPIDs to be transmitted are in increasing order of SPID but can be exchanged / switched except for the first SPID.

[0110] AP coordination has been considered as a potential technology to improve WLAN system throughput in the IEEE 802.1 Ibe standard and is still being discussed in the IEEE 802.11bn (UHR) standard. To support various AP coordination schemes, such as coordinated beamforming, OFDMA, TDMA, spatial reuse, and joint transmission, a predefined mechanism for APs is necessary.

[0111] In the context of coordinated TDMA (C-TDMA), the AP that obtains a transmit opportunity (TXOP) is referred to as the sharing AP. This AP initiates the AP coordination schemes to determine the AP candidate set by sending a frame, such as a Beacon frame or probe response frame, which includes information about the AP coordination scheme capabilities. The AP that participates in the AP coordination schemes after receiving the frame from the sharing AP is called the shared AP. The sharing AP is also known as the master AP or coordinating AP, while the shared AP is referred to as the slave AP or coordinated AP.

[0112] The operation of various AP coordination schemes has been discussed in the IEEE 802.1 Ibe and UHR standards:

[0113] Coordinated Beamforming (C-BF): Multiple APs transmit on the same frequency resource by coordinating and forming spatial nulls, allowing for simultaneous transmission from multiple APs.

[0114] Coordinated OFDMA (C-OFDMA): APs transmit on orthogonal frequency resources by coordinating and splitting the spectrum, enabling more efficient spectrum utilization.

[0115] Joint Transmission (JTX): Multiple APs transmit jointly to a given user simultaneously by sharing data between the APs.

[0116] Coordinated Spatial Reuse (C-SR): Multiple APs or STAs adjust their transmit power to reduce interference between APs.

[0117] By implementing these AP coordination schemes, WLAN systems can improve their overall throughput and efficiency by leveraging the cooperation between multiple APs.

[0118] C-SR is a type of multi-AP coordination scheme that is being considered for use in future wireless networks (e.g., wireless networks that will implement the upcoming IEEE 802.1 Ibn wireless networking standard (i.e., UHR)) to increase spectral efficiency and throughput. C-SR is attractive because it is simple to implement compared to other multi-AP coordination schemes. C-SR can allow two BSSs to simultaneously transmit / receive 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.

[0119] Figure 10 is a diagram showing two main phases of a C-SR procedure, according to some embodiments.

[0120] The C-SR procedure may be performed in a wireless network that includes a first AP (API), a second AP (AP2), a STA that is associated with API (STA11), and a STA that is associated with AP2 (STA21). API and STA11 may belong to a first BSS. AP2 and STA21 may belong to a second BSS. API and AP2 may coordinate with each other to achieve C-SR. In this example, API is the sharing AP and AP2 is the shared AP. The sharing AP may be an AP that initiates multi-AP coordination (e.g., for C-SR). The shared AP may be an AP that participates in multi-AP coordination with the sharing AP in response to the sharing AP’s initiation.

[0121] During C-SR in the downlink direction, API and AP2 may simultaneously transmit downlink frames to STA11 and STA21, respectively. API’s downlink transmission may cause interference (XI) at STA21 and AP2’s downlink transmission may cause interference (X2) atSTA11. To successfully achieve C-SR in the downlink direction, API and AP2 need to control their downlink transmit power to avoid / reduce the amount of downlink interference at the STAs.

[0122] As shown in the diagram, a C-SR procedure may 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 amount of interference at STA11 and STA12 may be used to determine the transmit power that API and AP2 should use to avoid / reduce downlink interference. During the C-SR transmission phase, API and AP2 may simultaneously transmit downlink frames to STA11 and STA21, respectively, using the determined transmit power to achieve C-SR.

[0123] Distributed tone RU (dRU) is a physical layer feature that is being considered for use in future wireless networks to improve spectral efficiency. dRU may help overcome the power spectral density (PSD) limitation. Various power modes are defined in 6 GHz bands such as standard power (SP) mode, very low power (VLP) mode, and low power indoor (LPI) mode. The PSD limitation is very tough especially in VLP mode and LPI mode in 6 GHz bands and especially for non-AP STAs. For example, the PSD limitation of a non-AP STA in LPI mode is -1 dBM / MHz. As a result, using many RU tones in a limited bandwidth can decrease transmit power due to the tough PSD limitation.

[0124] To successfully achieve C-SR, it is important to control the transmit power of each BSS so that simultaneous transmissions by the BSSs do not interfere with each other. The maximum allowable transmit power of a BSS may depend on the allowable interference level.

[0125] Figure 11 and Figure 12 are diagrams showing a communication sequence for an interference measurement phase. The difference between the communication sequence shown in Figure 11 and the communication sequence shown in Figure 12 is that the measurement frames (e.g., frame 1110 and frame 1115 shown in Figure 11) are transmitted simultaneously in the communication sequence shown in Figure 11 and the measurement frames (e.g., frame 1210 and frame 1215 shown in Figure 12) are transmitted sequentially (non-simultaneously) in the communication sequence shown in Figure 12. The communication sequence shown in Figure 11 may be referred to herein as option 1 and the communication sequence shown in Figure 12 may be referred to herein as option 2.

[0126] Figure 11 is a diagram showing a communication sequence for an interference measurement phase, according to some embodiments.

[0127] As shown in the diagram, API may transmit a M-AP trigger frame 1105 (“M-AP TF”) to AP2 to cause AP2 to transmit a measurement frame. The M-AP trigger frame 1105 may include information regarding a transmit power and / or a modulation coding scheme (MCS) thatAP2 is to use for transmitting a measurement frame. As used herein, a M-AP trigger frame may be any type of frame that can be used for initiating coordination between multiple APs.

[0128] After transmitting the M-AP trigger frame 1105, API may transmit measurement frame 1110 to STA11. Also, responsive to receiving the M-AP trigger frame 1105, AP2 may transmit measurement frame 1115 to STA21. In the example shown in the diagram (which reflects option 1), API’s transmission of measurement frame 1110 and AP2’s transmission of measurement frame 1115 occur simultaneously. The transmission of the measurement frames may allow the STAs to determine the amount of interference caused by an overlapping BSS (OBSS). In the example shown in the diagram, each AP transmits a single measurement frame. In some embodiments, each AP may transmit multiple frames to allow the STAs to determine the amount of interference caused by an OBSS. For example, each AP may sequentially transmit a null data packet announcement (NDP) frame and a NDP frame. As used herein, a measurement frame may be any type of frame that is transmitted for the purpose of allowing device(s) that receive / overhear the frame to determine / measure the channel state / characteristics based on the frame.

[0129] ST Al 1 may determine the amount of interference (X2) caused by the second BSS based on the received signal strengths (e.g., received signal strength indicator (RSSI)) of measurement frame 1110 and measurement frame 1115. Similarly, STA21 may determine the amount of interference (XI) caused by the first BSS based on the received signal strengths (e.g., received signal strength indicator (RSSI)) of measurement frame 1110 and measurement frame 1115. A STA may determine the received signal strength of a measurement frame using the preamble and / or the data part of the measurement frame (e.g., unless the frame is a NDP frame). If it is assumed that a STA knows the transmit power of a measurement frame, any difference between the transmit power of the measurement frame and the received signal strength of the measurement frame may be considered as being due to interference.

[0130] API may transmit an interference measurement feedback solicitation frame 1120 (“Solicit XI and X2”) to STA11 and STA21 that solicits interference measurements from STA11 and STA21. In some embodiments, API and AP2 may transmit separate interference measurement feedback solicitation frames to solicit interference measurements from STA11 and STA21, respectively. The example shown in the diagram is a case where API transmits an interference measurement feedback solicitation frame 1120 to STA11 and STA21 that solicits interference measurements from both STA11 and STA21. In an embodiment, the interference measurement feedback solicitation frame 1120 is a beamforming report (BFRP) trigger frame or a variation thereof. Responsive to receiving the interference measurement feedback solicitationframe 1120, STA11 may transmit a first interference measurement feedback frame 1125 (“feedback X2”) to the sharing AP that includes an indication of the amount of downlink interference (X2) caused by the second BSS at STA11. Similarly, responsive to receiving the interference measurement feedback solicitation frame 1120, STA21 may transmit a second interference measurement feedback frame 1130 (“feedback XI”) to the sharing AP that includes an indication of the amount of downlink interference (XI) caused by the first BSS at STA21.

[0131] After receiving the interference measurement feedback frames, API may determine a first downlink transmit power to be used by API and a second downlink transmit power to be used by AP2 based on the amount of downlink interference caused by the second BSS at STA11 and the amount of downlink interference caused by the first BSS at STA21. API may determine the first downlink transmit power and the second downlink transmit power in a manner that will reduce the amount of downlink interference caused by API and AP2 to achieve C-SR in the downlink direction.

[0132] API may transmit a power control information frame 1135 (“Share Power Control Info”) to AP2 that includes an indication of the first downlink transmit power and the second downlink transmit power. In an embodiment, the power control information frame 1135 only includes an indication of the second downlink transmit power (and not the first downlink transmit power).

[0133] During a C-SR transmission phase, API may transmit downlink frames to STA11 using the first downlink transmit power and AP2 may transmit downlink frames to STA21 using the second downlink transmit power. API’s transmission of downlink frames and AP2’s transmission of downlink frames may occur simultaneously to achieve C-SR in the downlink direction.

[0134] Figure 12 is a diagram showing a communication sequence for an interference measurement phase, according to some embodiments. The communication sequence shown in the diagram involves many of the same or similar frames / sequences as shown in Figure 11 and described above. One having ordinary skill in the art will appreciate that the descriptions provided above with regard to Figure 11 may also apply to the communication sequence shown in Figure 12. However, not all of the details are repeated herein for the sake of conciseness.

[0135] As shown in the diagram, API may transmit a M-AP trigger frame 1205 (“M-AP TF”) to AP2 to cause AP2 to transmit a measurement frame.

[0136] After transmitting the M-AP trigger frame 1105, API may transmit measurement frame 1210 to STA11. Also, responsive to receiving the M-AP trigger frame 1105, AP2 may transmit measurement frame 1215 to STA21. In the example shown in the diagram (whichreflects option 2), measurement frame 1210 and measurement frame 1215 are transmitted sequentially (non-simultaneously). In an embodiment, the M-AP trigger frame 1205 may include an indication of the timing / order of the measurement frame transmissions.

[0137] ST Al 1 may determine the amount of interference (X2) caused by the second BSS based on the received signal strengths (e.g., received signal strength indicator (RSSI)) of measurement frame 1210 and measurement frame 1215. Similarly, STA21 may determine the amount of interference (XI) caused by the first BSS based on the received signal strengths (e.g., received signal strength indicator (RSSI)) of measurement frame 1210 and measurement frame 1215.

[0138] In an embodiment, if a STA is aware of the received signal strength of a frame that was previously transmitted by its associated AP, the STA may determine the amount of interference caused by the OBSS at the STA as follows. The STA may determine the received signal strength of the frame previously transmitted by its associated AP through a beacon measurement request / report procedure. The STA may overhear the measurement frame transmitted by the OBSS AP and measure the received signal strength of this measurement frame. The STA may determine the amount of interference caused by the OBSS at the STA based on the known received signal strength of the frame that was previously transmitted by its associated AP and the received signal strength of the measurement frame transmitted by the OBSS AP. For example, STA11 may know the received signal strength of a frame previously transmitted by API (which is STA1 l’s associated AP) through a beacon measurement request / report procedure with API. Also, STA11 may overhear measurement frame 1215 transmitted by AP2 (which is an OBSS AP with respect to STA11) and measure the received signal strength of measurement frame 1215. STA11 may determine the amount of interference (X2) caused by the second BSS at STA11 based on the known received signal strength of the frame previously transmitted by API and the received signal strength of measurement frame 1215. STA21 may determine the amount of interference (XI) caused by the first BSS at STA21 in a similar manner.

[0139] In an embodiment, if a STA is not aware of the received signal strength of a frame that was previously transmitted by its associated AP, the STA may determine the amount of interference caused by the OBSS at the STA as follows. The STA may measure the received signal strength of the measurement frame transmitted by its associated AP. Also, the STA may measure the received signal strength of the measurement frame transmitted by the OBSS AP. The STA may implicitly determine the amount of interference caused by the OBSS at the STA based on the received signal strength of the measurement frame transmitted by its associated APand the received signal strength of the measurement frame transmitted by the OBSS AP. For example, STA11 may measure the received signal strength of measurement frame 1210 transmitted by API (which is STA1 l’s associated AP). Also, STA11 may measure the received signal strength of measurement frame 1215 transmitted by AP2 (which is an OBSS AP with respect to STA11). STA11 may implicitly determine the amount of interference (X2) caused by the second BSS at the STA based on the received signal strength of measurement frame 1210 transmitted by API and the received signal strength of measurement frame 1215 transmitted by AP2. STA21 may implicitly determine the amount of interference (XI) caused by the first BSS at STA21 in a similar manner.

[0140] API may transmit an interference measurement feedback solicitation frame 1220 (“Solicit XI and X2”) to STA11 and STA21 that solicits interference measurements from STA11 and STA21. Responsive to receiving the interference measurement feedback solicitation frame 1220, STA11 may transmit a first interference measurement feedback frame 1225 (“feedback X2”) to the sharing AP that includes an indication of the amount of downlink interference (X2) caused by the second BSS at STA11. Similarly, responsive to receiving the interference measurement feedback solicitation frame 1220, STA21 may transmit a second interference measurement feedback frame 1230 (“feedback XI”) to the sharing AP that includes an indication of the amount of downlink interference (XI) caused by the first BSS at STA21.

[0141] After receiving the interference measurement feedback frames, API may determine a first downlink transmit power to be used by API and a second downlink transmit power to be used by AP2 based on the amount of downlink interference caused by the second BSS at STA11 and the amount of downlink interference caused by the first BSS at STA21. API may determine the first downlink transmit power and the second downlink transmit power in a manner that will reduce the amount of downlink interference caused by API and AP2 to achieve C-SR in the downlink direction.

[0142] API may transmit a power control information frame 1235 (“Share Power Control Info”) to AP2 that includes an indication of the second downlink transmit power.

[0143] During a C-SR transmission phase, API may transmit downlink frames to STA11 using the first downlink transmit power and AP2 may transmit downlink frames to STA21 using the second downlink transmit power. API’s transmission of downlink frames and AP2’s transmission of downlink frames may occur simultaneously to achieve C-SR in the downlink direction.

[0144] Interference measurements may also be needed to achieve C-SR in the uplink direction. STAs may transmit in the uplink direction in a dRU to increase transmit power.

[0145] Figure 13 is a diagram showing uplink interference in a wireless network during C- SR, according to some embodiments.

[0146] The diagram shows a wireless network that has a similar configuration as the wireless network shown in Figure 10. For example, the wireless network includes API, AP2, STA11, and STA21. API and STA11 may belong to a first BSS. AP2 and STA21 may belong to a second BSS. API and AP2 may coordinate with each other to achieve C-SR. API is the sharing AP and AP2 is the shared AP.

[0147] During C-SR in the uplink direction, STA11 and STA21 may simultaneously transmit uplink frames to API and AP2, respectively. STA1 l’s uplink transmission may cause interference (Yl) at AP2 and STA2’s uplink transmission may cause interference (Y2) at API. To successfully achieve C-SR in the uplink direction, STA11 and STA21 need to control their uplink transmit power to avoid / reduce the amount of uplink interference. Also, STA11 and STA21 may transmit their uplink frames in a dRU to transmit with higher transmit power.

[0148] Techniques are described herein that allow an AP to determine the amount of uplink interference at the AP for a dRU so that the AP can determine the appropriate transmit power that STAs should use for uplink transmissions to the AP in the dRU to achieve C-SR in the uplink direction. It is assumed that the dRU that the STAs use for uplink transmissions are predefined or otherwise known. In an embodiment, STAs transmit interference measurement feedback frames (e.g., interference measurement feedback frames 1125 and 1130 shown in Figure 11) in the dRU. The AP may 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 strengths of the interference measurement feedback frames. The AP may determine an uplink transmit power that is to be used by the STAs for uplink transmissions based on the amount of uplink interference caused by its own BSS and the amount of uplink interference caused by the OBSS. Having the STAs transmit interference measurement feedback frames in the dRU allows the AP to determine the amount of uplink interference for the dRU without additional overhead (e.g., without transmitting / exchanging additional frames). That is, the interference measurement feedback frames may provide dual functionality: (1) they provide information regarding the amount of downlink interference at the STAs; and (2) they function as “measurement” frames for the uplink direction that allow an AP to determine the amount of uplink interference caused by an OBSS at the AP.

[0149] Figure 14 is a diagram showing a communication sequence for an interference measurement phase that allows for determining the amount of uplink interference for a dRU, according to some embodiments. The diagram shows two examples of communicationsequences. In the first communication sequence the measurement frames are transmitted simultaneously. In the second communication sequence the measurement frames are transmitted sequentially (non-simultaneously).

[0150] In the first example, as shown in the diagram, API may transmit a M-AP trigger frame 1402 (“M-AP TF”) to AP2 to cause AP2 to transmit a measurement frame.

[0151] After transmitting the M-AP trigger frame 1402, API may transmit measurement frame 1404 to STA11. Also, responsive to receiving the M-AP trigger frame 1402, AP2 may transmit measurement frame 1406 to STA21. In the first example, measurement frame 1404 and measurement frame 1406 are transmitted simultaneously.

[0152] ST Al 1 may determine the amount of downlink interference (X2) caused by the second BSS based on the received signal strengths (e.g., received signal strength indicator (RSSI)) of measurement frame 1404 and measurement frame 1406. Similarly, STA21 may determine the amount of downlink interference (XI) caused by the first BSS based on the received signal strengths (e.g., received signal strength indicator (RSSI)) of measurement frame 1404 and measurement frame 1406.

[0153] API may transmit an interference measurement feedback solicitation frame 1408 (“Solicit XI and X2”) to STA11 and STA21 that solicits interference measurements from STA11 and STA21. Responsive to receiving the interference measurement feedback solicitation frame 1408, STA11 may transmit a first interference measurement feedback frame 1410 (“Feedback X2 in dRU”) to the sharing AP in a 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, responsive to receiving the interference measurement feedback solicitation frame 1408, STA21 may transmit a second interference measurement feedback frame 1412 (“Feedback XI in dRU”) to API in the dRU. The second interference measurement feedback frame 1412 may include an indication of the amount of downlink interference (XI) caused by the first BSS at STA21.

[0154] API may determine the amount of uplink interference (Y2) caused by the second BSS at API and the amount of uplink interference (Yl) caused by the first BSS at AP2 based on the received signal strengths of the first interference measurement feedback frame 1410 and the second interference measurement feedback frame 1412. For example, API may know the transmit power of the first interference measurement feedback frame 1410 and the second interference measurement feedback frame 1412. Also, API may determine the received signal strengths of these frames using the preambles and / or data parts of these frames. Any difference between the transmit power of these frames and the received signal strengths of these frames canbe considered as being due to interference. In an embodiment, AP2 determines the amount of uplink interference (Yl) caused by the first BSS at AP2 and provides this information to API.

[0155] API may determine a first downlink transmit power to be used by API and a second downlink transmit power to be used by AP2 based on the amount of downlink interference (X2) caused by the second BSS at STA11 and the amount of downlink interference (XI) caused by the first BSS at STA21. Also, API may determine a first uplink transmit power to be used by STA11 and a second uplink transmit power to be used by STA 21 based on the amount of uplink interference (Y2) caused by the second BSS at API and the amount of uplink interference (Yl) caused by the first BSS at AP2.

[0156] API may transmit a power control information frame 1414 (“Share Power Control Info”) to AP2 that includes an indication of the first downlink transmit power, the second downlink transmit power, the first uplink transmit power, and the second uplink transmit power. In an embodiment, the power control information frame 1414 only includes indications of the second downlink transmit power and the second uplink transmit power (and not the first downlink transmit power and the first uplink transmit power).

[0157] During a C-SR transmission phase, API may transmit trigger frame 1416 (“TF”) to STA11 to solicit an uplink transmission from STA11 and AP2 may transmit trigger frame 1418 (“TF”) to STA21 to solicit an uplink transmission from STA21. API’s transmission of trigger frame 1416 and AP2’s transmission of trigger frame 1418 may occur simultaneously. API may transmit trigger frame 1416 using the first downlink transmit power and AP2 may transmit trigger frame 1418 using the second downlink transmit power to achieve C-SR in the downlink direction. 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 transmit uplink frame 1420 (“UL Data”) to API in the dRU and STA21 may transmit uplink frame 1422 (“UL Data”) to AP2 in the dRU. STA1 l’s transmission of uplink frame 1420 and STA2Ts transmission of uplink frame 1422 may occur simultaneously. STA11 may transmit uplink frame 1420 using the first uplink transmit power indicated in trigger frame 1416 and STA21 may transmit uplink frame 1422 using the second uplink transmit power indicated in trigger frame 1418 to achieve C-SR in the uplink direction.

[0158] In response to receiving uplink frame 1420, API may transmit acknowledgement frame 1424 (“ACK”) to STA11. Also, in response to receiving uplink frame 1422, AP2 may transmit ACK frame 1426 (“ACK”) to STA21. API’s transmission of ACK frame 1424 and AP2’s transmission of ACK frame 1426 may occur simultaneously.

[0159] In the second example, as shown in the diagram, API may transmit a M-AP trigger frame 1402 (“M-AP TF”) to AP2 to cause AP2 to transmit a measurement frame.

[0160] After transmitting the M-AP trigger frame 1452, API may transmit measurement frame 1454 to STA11. Also, responsive to receiving the M-AP trigger frame 1452, AP2 may transmit measurement frame 1456 to STA21. In the second example, measurement frame 1454 and measurement frame 1456 are transmitted sequentially (non-simultaneously). In an embodiment, the timing / order of the measurement frame transmissions is indicated in the M-AP trigger frame 1452.

[0161] API may transmit an interference measurement feedback solicitation frame 1458 (“Solicit XI and X2”) to STA11 and STA21 that solicits interference measurements from STA11 and STA21. Responsive to receiving the interference measurement feedback solicitation frame 1458, STA11 may transmit a first interference measurement feedback frame 1460 (“Feedback X2 in dRU”) to API in a 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, responsive to receiving the interference measurement feedback solicitation frame 1458, STA21 may transmit a second interference measurement feedback frame 1462 (“Feedback XI in dRU”) to API in the dRU. The second interference measurement feedback frame 1462 may include an indication of the amount of downlink interference (XI) caused by the first BSS at STA21.

[0162] API may determine the amount of uplink interference (Y2) caused by the second BSS and the amount of uplink interference (Yl) caused by the first BSS based on the received signal strengths of the first interference measurement feedback frame 1460 and the second interference measurement feedback frame 1462.

[0163] API may determine a first downlink transmit power to be used by API and a second downlink transmit power to be used by AP2 based on the amount of downlink interference (X2) caused by the second BSS at STA11 and the amount of downlink interference (XI) caused by the first BSS at STA21. Also, API may determine a first uplink transmit power to be used by STA11 and a second uplink transmit power to be used by STA 21 based on the amount of uplink interference (Y2) caused by the second BSS at API and the amount of uplink interference (Yl) caused by the first BSS at AP2.

[0164] API may transmit a power control information frame 1464 (“Share Power Control Info”) to AP2 that includes an indication of the first downlink transmit power, the second downlink transmit power, the first uplink transmit power, and the second uplink transmit power. In an embodiment, the power control information frame 1464 only includes indications of thesecond downlink transmit power and the second uplink transmit power (and not the first downlink transmit power and the first uplink transmit power).

[0165] During a C-SR transmission phase, API may transmit trigger frame 1466 (“TF”) to STA11 to solicit an uplink transmission from STA11 and AP2 may transmit trigger frame 1468 (“TF”) to STA21 to solicit an uplink transmission from STA21. API’s transmission of trigger frame 1466 and AP2’s transmission of trigger frame 1468 may occur simultaneously. API may transmit trigger frame 1466 using the first downlink transmit power and AP2 may transmit trigger frame 1468 using the second downlink transmit power to achieve C-SR in the downlink direction. 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 may transmit uplink frame 1470 (“UL Data”) to API in the dRU and STA21 may transmit uplink frame 1472 (“UL Data”) to AP2 in the dRU. STA1 l’s transmission of uplink frame 1470 and STA21’s transmission of uplink frame 1472 may occur simultaneously. STA11 may transmit uplink frame 1470 using the first uplink transmit power indicated in trigger frame 1466 and STA21 may transmit uplink frame 1472 using the second uplink transmit power indicated in trigger frame 1468 to achieve C-SR in the uplink direction.

[0166] In response to receiving uplink frame 1470, API may transmit ACK frame 1474 (“ACK”) to STA11. Also, in response to receiving uplink frame 1472, AP2 may transmit ACK frame 1476 (“ACK”) to STA21. API’s transmission of ACK frame 1474 and AP2’s transmission of ACK frame 1476 may occur simultaneously.

[0167] While particular communication sequences are shown in the diagrams and described herein, one having ordinary skill in the art will appreciate that the communication sequences can be modified to achieve the same result / effect without departing from the spirit and scope of the present disclosure. Thus, the communication sequences shown in the diagrams should be regarded as illustrative rather than limiting.

[0168] The techniques described herein allow STAs to provide information regarding the amount of downlink interference at the STAs to an AP. The AP may use such feedback information to control the downlink transmit power of coordinating APs in order to achieve successful C-SR in the downlink direction (without interference). Also, the STAs may transmit interference measurement feedback frames to the AP in a dRU to allow the AP to determine the amount of uplink interference for the dRU without adding additional overhead. The AP may use its knowledge of the amount of uplink interference for the dRU to control the uplink transmit power of STAs in order to achieve successful C-SR in the uplink direction (without interference).

[0169] Various embodiments are described herein in the context of soliciting / obtaining interference measurements for usage in C-SR. However, it should be appreciated that embodiments are not so limited. The techniques described herein can be used for soliciting / obtaining other types of channel information for other multi-AP coordination schemes. More generally, a first AP may transmit a M-AP frame to cause a second AP to transmit a measurement frame. A STA associated with the first AP may determine channel information based on the measurement frame transmitted by the second AP (and also based on a measurement frame transmitted by the first AP in some cases). The first AP may then transmit a channel information feedback solicitation frame that solicits channel information from the associated STA. Responsive to receiving the channel information feedback solicitation frame, the STA may transmit a channel information feedback frame to the first AP that includes the channel information. In this way, the first AP is able to determine how the second AP affects the channel state at first AP’s associated STA.

[0170] Turning now to Figure 15, a method 1500 will be described for achieving C-SR in the downlink direction, in accordance with an example embodiment. The method 1500 may be performed by a sharing AP that belongs to a first BSS to achieve C-SR with a shared AP that belongs to a second BSS. The sharing AP may be implemented by a wireless device (e.g., wireless device 104).

[0171] Additionally, although shown in a particular order, in some embodiments the operations of the method 1500 (and the other methods shown in the other figures) may be performed in a different order. For example, although the operations of the method 1500 are shown in a sequential order, some of the operations may be performed in partially or entirely overlapping time periods.

[0172] At operation 1505, the sharing AP transmits a M-AP trigger frame to the shared AP.

[0173] At operation 1510, after transmitting the M-AP trigger frame, the sharing AP transmits a first measurement frame to a first STA that belongs to the first BSS, wherein the shared AP transmits a second measurement frame to a second STA that belongs to the second BSS responsive to receiving the M-AP trigger frame from the sharing AP. In an embodiment, the M-AP trigger frame includes information regarding a transmit power that the shared AP is to use for transmitting the second measurement frame. In an embodiment, the first measurement frame comprises a plurality of frames. In an embodiment, the plurality of frames includes a NDPA frame and a NDP frame. In an embodiment, the first measurement frame and the second measurement frame are transmitted simultaneously. In an embodiment, the first measurement frame and the second measurement frame are transmitted non-simultaneously.

[0174] At operation 1515, the sharing AP transmits an interference measurement feedback solicitation frame that solicits an interference measurement from the first STA. In an embodiment, the interference measurement feedback solicitation frame is a BFRP trigger frame or a variation thereof.

[0175] At operation 1520, the sharing AP receives, as a response to the interference measurement feedback solicitation frame, an interference measurement feedback frame from the first STA that includes an indication of a first amount of downlink interference caused by the second measurement frame at the first STA. In an embodiment, the interference measurement feedback frame is transmitted by the first STA in a dRU.

[0176] At operation 1525, the sharing AP determines a second amount of downlink interference caused by the first measurement frame at the second STA. In an embodiment, the interference measurement feedback solicitation frame also solicits an interference measurement from the second STA, wherein the second amount of downlink interference is determined based on an indication of the second amount of downlink interference included in an interference measurement feedback frame received from the second STA.

[0177] At operation 1530, the sharing AP determines a first downlink transmit power to be used by the sharing AP and a second downlink transmit power to be used by the shared AP based on the first amount of downlink interference and the second amount of downlink interference.

[0178] At operation 1535, the sharing AP transmits a power control information frame to the shared AP that includes an indication of the second downlink transmit power. In an embodiment, the power control information frame further includes an indication of the first downlink transmit power.

[0179] At operation 1540, the sharing AP transmits a first downlink frame to the first STA using the first downlink transmit power, wherein the sharing AP simultaneously transmits a second downlink frame to the second STA using the second downlink transmit power.

[0180] Turning now to Figure 16, a method 1600 will be described for achieving C-SR in the uplink direction, in accordance with an example embodiment. The method 1600 may be performed by a sharing AP that coordinates with a 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). The sharing AP may combine method 1500 and method 1600 to achieve C-SR in both the downlink and uplink directions with minimal overhead, as described above.

[0181] At operation 1605, the sharing AP determines a first amount of uplink interference at the sharing AP and a second amount of uplink interference at the shared AP based on a received signal strength of a first interference measurement feedback frame received from a first STA that belongs to the first BSS (e.g., in a dRU) and a received signal strength of a second interference measurement feedback frame transmitted by a second STA that belongs to the second BSS.

[0182] At operation 1610, the sharing AP determines a first uplink transmit power that is to be used by the first STA and a second uplink transmit power that is to be used by the second STA based on the first amount of uplink interference and the second amount of uplink interference, wherein an indication of the second uplink transmit power is included in a power control information frame that is transmitted by the sharing AP to the shared AP.

[0183] At operation 1615, the sharing AP transmits a first trigger frame to the first STA that solicits an uplink transmission from the first STA, wherein the first trigger frame includes an indication of the first uplink transmit power. The shared AP may simultaneously transmit a second trigger frame to the second STA that solicits an uplink transmission from the second STA, wherein the second trigger frame includes an indication of the second uplink transmit power.

[0184] At operation 1620, the sharing AP receives, as a response to the first trigger frame, a first uplink frame from the first STA, wherein the first STA transmits the first uplink frame to the sharing AP (e.g., in the dRU) using the first uplink transmit power (which was indicated in the first trigger frame). The second STA may simultaneously transmit a second uplink frame to the shared AP using the second uplink transmit power (which was indicated in the first trigger frame) as a response to the second trigger frame.

[0185] Turning now to Figure 17, a method 1700 will be described for providing downlink interference measurement feedback information, in accordance with an example embodiment. The method 1700 may be performed by a STA to provide downlink interference measurement feedback information to an AP. The STA and the AP may belong to a first BSS that overlaps with a second BSS. The STA may be implemented by a wireless device (e.g., wireless device 104).

[0186] At operation 1705, the STA determines an amount of downlink interference caused by the second BSS at the STA.

[0187] At operation 1710, the STA receives an interference measurement feedback solicitation frame from the AP that solicits an interference measurement. In an embodiment, theinterference measurement feedback solicitation frame is a BFRP trigger frame or a variation thereof.

[0188] At operation 1715, responsive to receiving the interference measurement feedback solicitation frame, the STA transmits an interference measurement feedback frame to the AP (e.g., in a dRU) that includes an indication of the amount of downlink interference at the STA.

[0189] In an embodiment, at 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 that was determined based on the amount of downlink interference at the STA and an amount of downlink interference caused by the first BSS at a second STA that belongs to the second BSS, wherein a second AP that belongs to the second BSS simultaneously transmits a downlink frame to the second STA to achieve C-SR in the downlink direction.

[0190] In an embodiment, at operation 1725, the STA receives a trigger frame from the AP that solicits an uplink transmission from the STA, wherein the trigger frame includes an indication of an uplink transmit power to be used by the STA.

[0191] In an embodiment, at operation 1730, responsive to receiving the trigger frame, the STA transmits an uplink frame to the AP in the dRU using the uplink transmit power (which was indicated in the trigger frame).

[0192] In an embodiment, the STA receives a first measurement frame from the AP, determines a received signal strength of the first measurement frame, overhears a second measurement frame transmitted by a second AP that belongs to the second BSS, and determines a received signal strength of the second measurement frame. The STA may determine the amount of downlink interference (caused by the second BSS at the STA) based on the received signal strength of the first measurement frame and the received signal strength of the second measurement frame. In an embodiment, the first measurement frame comprises a plurality of frames. In an embodiment, the plurality of frames includes a NDPA frame and a NDP frame.

[0193] In an embodiment, the STA overhears a measurement frame transmitted by a second AP that belongs to the second BSS and determines a received signal strength of the measurement frame. The STA may determine the amount of downlink interference (caused by the second BSS at the STA) based on a received signal strength obtained through a beacon measurement request / report phase with the AP and the received signal strength of the measurement frame.

[0194] Turning now to Figure 18, a method 1800 will be described for obtaining channel information, in accordance with an example embodiment. The method 1800 may be performed by a first AP to obtain channel information in coordination with a second AP. The first AP maybelong 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).

[0195] At operation 1805, the first AP transmits a M-AP trigger frame to the second AP to cause the second AP to transmit a measurement frame.

[0196] At operation 1810, the first AP transmits a channel information feedback solicitation frame that solicits the channel information from a STA that belongs to the first BSS. In an embodiment, the channel information feedback solicitation frame is a BFRP trigger frame or a variation thereof.

[0197] At operation 1815, the first AP receives, as a response to the channel information feedback solicitation frame, a channel information feedback frame from the STA that includes the channel information, wherein the channel information was determined by the STA based on the measurement frame transmitted by the second AP. In an embodiment, the measurement frame is a NDP frame.

[0198] In an 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 was further determined by the STA based on the second measurement frame transmitted by the first AP. In an embodiment, the channel information included in the channel information feedback frame includes information regarding an amount of interference caused by the measurement frame transmitted by the second AP at the STA.

[0199] Turning now to Figure 19, a method 1900 will be described for providing channel information, in accordance with an example embodiment. The method 1900 may be performed by a STA to provide channel information to a first AP that is 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).

[0200] At operation 1905, the STA receives a measurement frame from a second AP that belongs to the second BSS.

[0201] At operation 1910, the STA determines channel information based on the measurement frame. In an embodiment, the measurement frame is a NDP frame. In an embodiment, the STA receives a second measurement frame from the first AP simultaneously with the measurement frame received from the second AP. The STA may determine the channel information further based on the second measurement frame. In an embodiment, the channel information includes information regarding an amount of interference caused by the measurement frame received from the second AP at the STA.

[0202] At operation 1915, the STA receives a channel information feedback solicitation frame from the first AP that solicits the channel information. In an embodiment, the channel information feedback solicitation frame is a BFRP trigger frame or a variation thereof.

[0203] At operation 1920, responsive to receiving the channel information feedback solicitation frame, the STA transmits a channel information feedback frame to the first AP that includes the channel information.

[0204] Although many of the solutions and techniques provided herein have been described with reference to a WLAN system, it should be understood that these solutions and techniques are also applicable to other network environments, such as cellular telecommunication networks, wired networks, etc. In some embodiments, the solutions and techniques provided herein may be or may be embodied in an article of manufacture in which a non-transitory machine-readable medium (such as microelectronic memory) has stored thereon instructions which program one or more data processing components (generically referred to here as a “processor” or “processing unit”) to perform the operations described herein. In other embodiments, some of these operations might be performed by specific hardware components that contain hardwired logic (e.g., dedicated digital filter blocks and state machines). Those operations might alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

[0205] In some cases, an embodiment may be an apparatus (e.g., an AP STA, a non-AP STA, or another 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, an apparatus may include a memory unit, which stores instructions that may be executed by a hardware processor installed in the apparatus. The apparatus may also include one or more other hardware or software elements, including a network interface, a display device, etc.

[0206] Some portions of the preceding detailed descriptions have been presented in terms of algorithms and symbolic representations of operations on data bits within a computer memory. These algorithmic descriptions and representations are the ways used by those skilled in the data processing arts to most effectively convey the substance of their work to others skilled in the art. An algorithm is here, and generally, conceived to be a self-consi stent sequence of operations leading to a desired result. The operations are those requiring physical manipulations of physical quantities. Usually, though not necessarily, these quantities take the form of electrical or magnetic signals capable of being stored, combined, compared, and otherwise manipulated.It has proven convenient at times, principally for reasons of common usage, to refer to these signals as bits, values, elements, symbols, characters, terms, numbers, or the like.

[0207] It should be borne in mind, however, that all of these and similar terms are to be associated with the appropriate physical quantities and are merely convenient labels applied to these quantities. The present disclosure can refer to the action and processes of a computer system, or similar electronic computing device, that manipulates and transforms data represented as physical (electronic) quantities within the computer system's registers and memories into other data similarly represented as physical quantities within the computer system memories or registers or other such information storage systems.

[0208] The present disclosure also relates to an apparatus for performing the operations herein. This apparatus can be specially constructed for the intended purposes, or it can include a general -purpose computer selectively activated or reconfigured by a computer program stored in the computer. For example, a computer system or other data processing system may carry out the computer-implemented methods described herein in response to its processor executing a computer program (e.g., a sequence of instructions) contained in a memory or other non- transitory machine-readable storage medium. Such a computer program can 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 magnetic-optical disks, read-only memories (ROMs), random access memories (RAMs), EPROMs, EEPROMs, magnetic or optical cards, or any type of media suitable for storing electronic instructions, each coupled to a computer system bus.

[0209] The algorithms and displays presented herein are not inherently related to any particular computer or other apparatus. Various general -purpose systems can be used with programs in accordance with the teachings herein, or it can prove convenient to construct a more specialized apparatus to perform the method. The structure for a variety of these systems will appear as set forth in the description below. In addition, the present disclosure is not described with reference to any particular programming language. It will be appreciated that a variety of programming languages can be used to implement the teachings of the disclosure as described herein.

[0210] The present disclosure can be provided as a computer program product, or software, that can include a machine-readable medium having stored thereon instructions, which can be used to program a computer system (or other electronic devices) to perform a process according to the present disclosure. A machine-readable medium includes any mechanism for storing information in a form readable by a machine (e.g., a computer). In some embodiments, a machine-readable (e.g., computer-readable) medium includes a machine (e.g., a computer)readable storage medium such as a read only memory (“ROM”), random access memory (“RAM”), magnetic disk storage media, optical storage media, flash memory components, etc.

[0211] In the foregoing specification, embodiments of the disclosure have been described with reference to specific example embodiments thereof. It will be evident that various modifications can be made thereto without departing from the broader spirit and scope of embodiments of the disclosure as set forth in the following claims. The specification and drawings are, accordingly, to be regarded in an illustrative sense rather than a restrictive sense.

Claims

CLAIMSWhat is claimed is:

1. A method performed by a sharing access point (AP) to achieve coordinated spatial reuse (C-SR) with a shared AP, wherein the sharing AP belongs to a first basic service set (BSS) and the shared AP belongs to a second BSS, the method comprising: transmitting a multi-AP (M-AP) trigger frame to the shared AP; after transmitting the M-AP trigger frame, transmitting a first measurement frame to a first station (STA) that belongs to the first BSS, wherein the shared AP transmits a second measurement frame to a second STA that belongs to the second BSS responsive to receiving the M-AP trigger frame from the sharing AP; transmitting an interference measurement feedback solicitation frame that solicits an interference measurement from the first STA; receiving, as a response to the interference measurement feedback solicitation frame, an interference measurement feedback frame from the first STA that includes an indication of a first amount of downlink interference caused by the second measurement frame at the first STA; determining a second amount of downlink interference caused by the first measurement frame at the second STA; determining a first downlink transmit power to be used by the sharing AP and a second downlink transmit power to be used by the shared AP based on the first amount of downlink interference and the second amount of downlink interference; transmitting a power control information frame to the shared AP that includes an indication of the second downlink transmit power; and transmitting a first downlink frame to the first STA using the first downlink transmit power, wherein the sharing AP simultaneously transmits 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 regarding a transmit power that the shared AP is to use for transmitting the second measurement frame.

3. The method of 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 data packet announcement (NDPA) frame and a null data packet (NDP) frame.

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

6. The method of claim 1, wherein the first measurement frame and the second measurement frame are transmitted non-simultaneously.

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

8. The method of claim 1, wherein the interference measurement feedback solicitation frame is a beamforming report (BFRP) trigger frame or a variation 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 transmitted by the first STA in a distributed resource unit (dRU).

11. The method of claim 10, further comprising: determining a first amount of uplink interference at the sharing AP and a second amount of uplink interference at the shared AP based on a received signal strength of the interference measurement feedback frame received from the first STA and a received signal strength of a second interference measurement feedback frame transmitted by the second STA; determining a first uplink transmit power that is to be used by the first STA and a second uplink transmit power that is to be used by the second STA based on the first amount of uplink interference and the second amount of uplink interference, wherein an indication of the second uplink transmit power is included in the power control information frame; transmitting a first trigger frame to the first STA using the first downlink transmit power that solicits an uplink transmission from the first STA, wherein the first triggerframe includes an indication of the first uplink transmit power, wherein the shared AP simultaneously transmits a second trigger frame to the second STA using the second downlink transmit power that solicits an uplink transmission from the second STA, wherein the second trigger frame includes an indication of the second uplink transmit power; and receiving, as a response to the first trigger frame, a first uplink frame from the first STA, wherein the first STA transmits the first uplink frame to the sharing AP in the dRU using the first uplink transmit power, wherein the second STA simultaneously transmits a second uplink frame to the shared AP using the second uplink transmit power as a response to the second trigger frame.

12. A method performed by a station (STA) to provide interference measurement feedback information to an access point (AP), wherein the AP and the STA belong to a first basic service set (BSS) that overlaps with a second BSS, the method comprising: determining an amount of downlink interference caused by the second BSS at the STA; receiving an interference measurement feedback solicitation frame from the AP that solicits an interference measurement; and responsive to receiving the interference measurement feedback solicitation frame, transmitting an interference measurement feedback frame to the AP that includes an indication of the amount of downlink interference at the STA.

13. The method of claim 12, further comprising: receiving a downlink frame from the AP, wherein the downlink frame is transmitted by the AP using a downlink transmit power that was determined based on the amount of downlink interference at the STA and an amount of downlink interference caused by the first BSS at a second STA that belongs to the second BSS, wherein a second AP that belongs to the second BSS simultaneously transmits a downlink frame to the second STA to achieve coordinated spatial reuse.

14. The method of claim 12, wherein the interference measurement feedback solicitation frame is a beamforming report (BFRP) trigger frame or a variation 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: receiving a trigger frame from the AP that solicits an uplink transmission from the STA, wherein the trigger frame includes an indication of an uplink transmit power to be used by the STA; and responsive to receiving the trigger frame, transmitting an uplink frame to the AP in the dRU using the uplink transmit power.

17. The method of claim 12, further comprising: receiving a first measurement frame from the AP; determining a received signal strength of the first measurement frame; overhearing a second measurement frame transmitted by a second AP that belongs to the second BSS; and determining a received signal strength of the second measurement frame, wherein the amount of downlink interference 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 data packet announcement (NDPA) frame and a null data packet (NDP) frame.

20. The method of claim 12, further comprising: overhearing a measurement frame transmitted by a second AP that belongs to the second BSS; and determining a received signal strength of the measurement frame, wherein the amount of interference is determined based on a received signal strength obtained through a 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) to obtain channel information in coordination with a second AP, wherein the first AP belongs to a first basic service set (BSS) and the second AP belongs to a second BSS, the method comprising: transmitting a multi-AP (M-AP) trigger frame to the second AP to cause the second AP to transmit a measurement frame;transmitting a channel information feedback solicitation frame that solicits the channel information from a station (STA) that belongs to the first BSS; and receiving, as a response to the channel information feedback solicitation frame, a channel information feedback frame from the STA that includes the channel information, wherein the channel information was determined by the STA based on the measurement frame transmitted by the second AP.

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

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

24. The method of claim 21, further comprising: transmitting 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 was further determined by the STA based on the second measurement frame transmitted by the first AP.

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

26. A method performed by a station (STA) to provide channel information to a first access point (AP) that is coordinating with a second 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: receiving a measurement frame from a second AP that belongs to the second BSS; determining the channel information based on the measurement frame; receiving a channel information feedback solicitation frame from the first AP that solicits the channel information; and responsive to receiving the channel information feedback frame, transmitting a channel information feedback frame to the first AP that includes the channel information.

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

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

29. The method of claim 26, further comprising: receiving a second measurement frame from the first AP simultaneously with the measurement frame received from the second 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 regarding an amount of interference caused by the measurement frame received from the second AP at the STA.

31. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 1-11.

32. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 12-20.

33. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; and a processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 21-25.

34. A wireless device comprising: a radio frequency transceiver; a memory device storing a set of instructions; anda processor coupled to the memory device, wherein the set of instructions, when executed by the processor, causes the wireless device to perform the method of any one of claims 26-30.

Images