Coordinated spatial reuse

Abstract

In some implementations, a first access point (AP) selects one or more other APs to participate in a coordinated access point transmission session with the first AP. The first AP obtains a transmit opportunity (TXOP) and transmits a frame indicating scheduling information for uplink (UL) or downlink (DL) transmissions to or from the selected AP, the scheduling information indicating respective start times of the UL or DL transmissions to or from the selected AP, at least two of the start times being offset from each other by a time period associated with a decoded preamble of a wireless packet. The first AP transmits or receives wireless packets to or from one or more associated stations (STAs) based on the scheduling information, at least partially concurrently with the selected AP transmitting or receiving wireless packets to or from their respective associated stations (STAs).

Description

[0001] Cross-references

[0002] This patent application claims the benefit of U.S. patent application No. 17 / 651,401, entitled “COORDINATED SPATIAL REUSE,” filed by SUN et al. on February 16, 2022, which is assigned to the assignee of this patent application. Technical Field

[0003] The present disclosure relates generally to wireless networks, and more particularly to coordinating spatial reuse transmissions to or from multiple access points (APs) associated with different basic service sets (BSSs).

[0004] Description of Related Technology

[0005] A wireless local area network (WLAN) can be formed by one or more access points (APs) that provide a shared wireless communication medium for use by multiple client devices, also known as stations (STAs). The fundamental building block of a WLAN that complies with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards is the Basic Service Set (BSS) managed by the AP. Each BSS is identified by a Basic Service Set Identifier (BSSID) announced by the AP. The AP periodically broadcasts beacon frames to enable any STA within the AP's wireless range to establish or maintain a communication link with the WLAN.

[0006] Many wireless networks use a random channel access mechanism during which wireless devices (including APs and STAs) contend with each other for access to the wireless medium. The wireless device that wins the contention operation becomes the owner of a transmit opportunity (TXOP) and may use the wireless medium for the duration of the TXOP. For example, to prevent interference with transmissions from the TXOP owner, other wireless devices are typically prevented from transmitting data during the TXOP. 802.11ax, 802.11be, and subsequent amendments to the IEEE 802.11 family of wireless communication standards allow an AP that obtains a TXOP on the wireless medium to share some or all of the obtained TXOP with one or more STAs associated with the AP.

[0007] An AP associated with a first BSS may operate in the presence of other APs belonging to BSSs other than the first BSS. Typically, there is a lack of coordination between the first AP and the other APs, and transmissions associated with these other overlapping BSSs (OBSSs) may interfere with transmissions associated with the first BSS. While spatial reuse (SR) techniques may allow the first AP to transmit data to its associated STAs in the presence of OBSS interference, the lack of coordination between SR transmissions and OBSS transmissions may limit the extent to which OBSSs can operate in close proximity to each other. Summary of the Invention

[0008] The systems, methods, and devices of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0009] One innovative aspect of the subject matter described in the present disclosure can be implemented as a method for wireless communications by a first access point (AP) associated with a first basic service set (BSS). In some implementations, the method includes selecting one or more other APs to participate in a coordinated access point transmission session on a wireless medium with the first AP, the one or more selected APs being associated with respective BSSs other than the first BSS. The method may include obtaining a transmit opportunity (TXOP) on the wireless medium; and transmitting a frame indicating scheduling information for uplink (UL) or downlink (DL) transmissions to or from each of the selected APs during at least a portion of the TXOP obtained by the first AP, the scheduling information indicating respective start times of respective UL or DL transmissions to or from each of the selected APs during at least a portion of the TXOP obtained by the first AP, at least two of the start times being offset from each other by a time period associated with a preamble of a decoded wireless packet. The method may include transmitting, with each of the selected APs, one or more respective wireless packets to or from one or more respective STAs associated with the respective APs based on the scheduling information, at least partially concurrently with transmitting, with or from one or more STAs associated with the first AP. In some aspects, the frame indicates whether the coordinating access point transmit session is designated for UL transmission or DL transmission.

[0010] In various implementations, the respective start times of the UL or DL transmissions to or from the selected APs are based at least in part on one or both of a signal strength of wireless packets received by the first AP from the selected APs or an interference level associated with the selected APs. In some instances, the respective start times of the UL or DL transmissions to or from at least some of the selected APs are the same based at least in part on the respective signal strengths or interference levels associated with at least some of the selected APs being less than a certain value. In some other instances, the respective start times of the UL or DL transmissions to or from at least two of the selected APs are offset from each other by a period of time based at least in part on the respective signal strengths or interference levels associated with the at least two selected APs being greater than a certain value.

[0011] In some implementations, the scheduling information may also indicate one or more of a respective modulation and coding scheme (MCS) to be used for the UL or DL transmissions to or from each of the selected APs, a respective transmit power level to be used for the UL or DL transmissions to or from each of the selected APs, or a respective duration of the UL or DL transmissions to or from each of the selected APs. In some instances, the respective durations of the UL or DL transmissions to or from the selected APs may be the same. In other instances, the respective durations of the UL or DL transmissions to or from the selected APs may differ from each other by a second time period. In some aspects, the second time period may be associated with a preamble of a decoding acknowledgement (ACK) frame or a block acknowledgement (BA) frame.

[0012] In other specific implementations, the frame may further indicate the respective durations of ACK frames or BA frames to be transmitted by one or more STAs associated with the respective APs in the selected APs. In some instances, the respective durations of the ACK frames or BA frames may be the same as one another. In other instances, the respective durations of the ACK frames or BA frames may be offset in time from one another.

[0013] In various implementations, the method further includes sending a polling frame to a plurality of APs associated with a BSS different from the first BSS. The method may further include receiving, in response to the polling frame, a request from one or more of the plurality of APs for the first AP to share a portion of the obtained TXOP with the respective APs. The method may further include selecting, based on the received request, one or more APs to participate in the coordinated access point transmission session. In some implementations, the method further includes selectively adjusting a length or duration of each of the one or more wireless packets sent to or received from one or more STAs associated with the first AP based at least in part on one or more of the respective signal strengths of the wireless packets received by the first AP from the selected APs, respective interference levels associated with the selected APs, or respective decoding error rates of the first AP and the selected APs. In some instances, the frame includes instructions for each of the selected APs to send scheduling information to the one or more STAs associated with the respective selected APs. In some aspects, the scheduling information is sent to the one or more STAs associated with the first AP as respective non-high throughput (HT) copies over corresponding multiple subchannels of the wireless medium.

[0014] Another innovative aspect of the subject matter described in this disclosure can be implemented in a wireless communication device. The wireless communication device may include at least one processor and at least one memory communicatively coupled to the at least one processor. In some implementations, the at least one memory stores processor-readable code that, when executed by the at least one processor, is configured to: select one or more other APs to participate in a coordinated access point transmission session on a wireless medium with a first AP, the one or more selected APs being associated with respective BSSs other than the first BSS. Execution of the processor-readable code may further be configured to: obtain a TXOP on the wireless medium, and transmit a frame indicating scheduling information for UL or DL transmissions to or from each of the selected APs during at least a portion of the TXOP obtained by the first AP, the scheduling information indicating respective start times of respective UL or DL transmissions to or from each of the selected APs during at least a portion of the TXOP obtained by the first AP, at least two of the start times being offset from each other by a time period associated with a preamble of a decoded wireless packet. The execution of the processor-readable code can be configured to: send one or more corresponding wireless packets to one or more corresponding STAs associated with the corresponding AP or receive one or more corresponding wireless packets from one or more corresponding STAs associated with the corresponding AP with each selected AP based on the scheduling information, and at least partially concurrently send one or more wireless packets to one or more STAs associated with the first AP or receive one or more wireless packets from one or more STAs associated with the first AP.

[0015] In various implementations, the respective start times of the UL or DL transmissions to or from the selected APs are based at least in part on one or both of a signal strength of wireless packets received by the first AP from the selected APs or an interference level associated with the selected APs. In some instances, the respective start times of the UL or DL transmissions to or from at least some of the selected APs are the same based at least in part on the respective signal strengths or interference levels associated with at least some of the selected APs being less than a certain value. In some other instances, the respective start times of the UL or DL transmissions to or from at least two of the selected APs are offset from each other by a period of time based at least in part on the respective signal strengths or interference levels associated with the at least two selected APs being greater than a certain value.

[0016] In some implementations, the scheduling information may further indicate one or more of a respective MCS to be used for the UL or DL transmissions to or from each of the selected APs, a respective transmit power level to be used for the UL or DL transmissions to or from each of the selected APs, or a respective duration of the UL or DL transmissions to or from each of the selected APs. In some instances, the respective durations of the UL or DL transmissions to or from the selected APs may be the same. In other instances, the respective durations of the UL or DL transmissions to or from the selected APs may differ from each other by a second time period. In some aspects, the second time period may be associated with decoding a preamble of an ACK frame or a BA frame.

[0017] In other specific implementations, the frame may further indicate the respective durations of ACK frames or BA frames to be transmitted by one or more STAs associated with the respective APs in the selected APs. In some instances, the respective durations of the ACK frames or BA frames may be the same as one another. In other instances, the respective durations of the ACK frames or BA frames may be offset in time from one another.

[0018] In various implementations, execution of the processor-readable code for selecting one or more APs may be configured to send a polling frame to multiple APs associated with a BSS different from a first BSS. Execution of the processor-readable code may be further configured to receive, in response to the polling frame, a request from one or more of the multiple APs for the first AP to share a portion of an acquired TXOP with the respective AP. Execution of the processor-readable code may be further configured to select one or more APs to participate in a coordinated access point transmission session based on the received request. In some implementations, execution of the processor-readable code may be further configured to selectively adjust the length or duration of each of the one or more wireless packets sent to or received from one or more STAs associated with the first AP based at least in part on one or more of the respective signal strengths of wireless packets received by the first AP from the selected APs, respective interference levels associated with the selected APs, or respective decoding error rates of the first AP and the selected APs. In some instances, the frame includes instructions for each of the selected APs to send scheduling information to one or more respective STAs associated with the respective selected APs. In some aspects, the scheduling information is transmitted as a respective plurality of non-HT copies to one or more STAs associated with the first AP over a corresponding plurality of sub-channels of the wireless medium.

[0019] The details of one or more specific implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. Note that relative dimensions in the drawings may not be drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic diagram of an example wireless communication network is shown.

[0021] Figure 2A Example protocol data units (PDUs) that may be used for communications between an access point (AP) and one or more wireless stations (STAs) are shown.

[0022] Figure 2B Shown Figure 2A Example fields in the PDU.

[0023] Figure 3A Another example PDU that may be used for communication between an AP and one or more STAs is shown.

[0024] Figure 3B Another example PDU that may be used for communication between an AP and one or more STAs is shown.

[0025] Figure 4 Example physical layer convergence protocol (PLCP) protocol data units (PPDUs) that may be used for communication between an AP and several STAs are shown.

[0026] Figure 5 A block diagram of an example wireless communication device is shown.

[0027] Figure 6A A block diagram of an example access point (AP) is shown.

[0028] Figure 6B A block diagram of an example station (STA) is shown.

[0029] Figure 7A A timing diagram illustrating example wireless communications supporting coordinated spatial reuse of uplink (UL) transmissions in accordance with some implementations is shown.

[0030] Figure 7B A timing diagram illustrating example wireless communications supporting coordinated spatial reuse of downlink (DL) transmissions according to some other implementations is shown.

[0031] Figure 8 A timing diagram illustrating another example wireless communication supporting coordinated spatial reuse of DL transmissions according to some implementations is shown.

[0032] Figures 9A to 9CA timing diagram illustrating example wireless communications supporting coordinated spatial reuse of DL transmissions according to some other implementations is shown.

[0033] Figure 10 A timing diagram illustrating example wireless communications supporting coordinated spatial reuse of UL transmissions according to some other implementations is shown.

[0034] Figure 11 A flow chart illustrating an example process for wireless communications supporting coordinated spatial reuse transmissions according to some implementations is shown.

[0035] Figure 12 A flow chart illustrating an example process for wireless communications supporting coordinated spatial reuse transmissions according to some implementations is shown.

[0036] Figure 13 A flow chart illustrating an example process for wireless communications supporting coordinated spatial reuse transmissions according to some implementations is shown.

[0037] Figure 14A An example spatial reuse (SR) start frame is shown according to some implementations.

[0038] Figure 14B An example SR start frame according to some other implementations is shown.

[0039] Figure 15 A block diagram of an example wireless communication device is shown, according to some implementations.

[0040] The same reference numbers and names in different drawings represent the same elements. DETAILED DESCRIPTION

[0041] The following description is directed to some specific implementations for the purpose of describing the innovative aspects of the present disclosure. However, one of ordinary skill in the art will readily recognize that the teachings herein can be applied in a variety of different ways. The described implementations can be implemented in any device, system, or network capable of sending and receiving radio frequency (RF) signals in accordance with one or more of the following: Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards promulgated by the 3rd Generation Partnership Project (3GPP), the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, or as defined by the Bluetooth Special Interest Group (SIG). Standards, etc. The described implementations may be implemented in any device, system, or network capable of sending and receiving RF signals according to one or more of the following technologies or techniques: code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), single-user (SU) multiple-input multiple-output (MIMO), and multi-user (MU) MIMO. The described implementations may also be implemented using other wireless communication protocols or RF signals suitable for use in one or more of a wireless wide area network (WWAN), a wireless personal area network (WPAN), a wireless local area network (WLAN), or an Internet of Things (IoT) network.

[0042] Various embodiments generally relate to sharing resources of a wireless medium with a group of wireless communication devices, regardless of which wireless communication device is the owner of a transmit opportunity (TXOP) on the wireless medium. More specifically, some embodiments relate to a first access point (AP) managing a first basic service set (BSS) sharing some or all of the obtained TXOPs on the wireless medium with other APs associated with other overlapping BSSs (OBSSs) operating independently of the first BSS. In some embodiments, the first AP may select one or more of the other APs to participate in a coordinated access point transmit session with the first AP, during which the first AP shares at least a portion of the TXOP with the one or more selected APs for uplink (UL) transmissions to the selected APs or downlink (DL) transmissions from the selected APs. In some examples, the first AP may request or obtain information indicating whether the other APs intend to participate in the coordinated access point transmit session and, if so, request an amount of wireless resources to be shared by the first AP. The first AP may use the obtained information to determine or select which of the other APs to permit as participants in the coordinated access point transmit session. After obtaining a TXOP on the wireless medium, the first AP may send a frame to one or more selected APs indicating scheduling information for UL transmissions to or DL transmissions from each of the selected APs during a specified portion of the TXOP obtained by the first AP. The scheduling information may be based at least in part on one or more of respective signal strengths of wireless packets received from the selected APs, respective interference levels associated with the selected APs, respective decoding error rates of the first AP and the selected APs, or wireless resources requested by the selected APs.

[0043] During a coordinated access point transmission session, a first AP may, based on scheduling information, transmit or receive one or more corresponding wireless packets to or from one or more corresponding STAs associated with the respective APs at least partially concurrently with the selected APs. In some implementations, the scheduling information indicates a respective start time for UL or DL transmissions to or from each of the selected APs during at least a portion of a TXOP obtained by the first AP. In some instances, the respective start times may be the same as one another. In other instances, the respective start times may be offset from one another by the time period. In some aspects, the time period may be based on an amount of time associated with the participating APs decoding a preamble of a wireless packet and determining, based on the decoded preamble, whether the wireless packet is an intra-BSS packet or an OBSS packet.

[0044] Certain implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages. By allowing a group of APs associated with different BSSs to participate in a coordinated access point transmission session during which the group of APs may share at least a portion of a TXOP obtained by any of the participating APs, aspects of the present disclosure may increase the throughput of the wireless medium across all of the BSSs associated with the participating APs. Furthermore, by scheduling UL transmissions to or DL transmissions from participating APs at start times that may be the same as one another or offset by a period of time, aspects of the present disclosure may maximize medium utilization while also minimizing packet loss due to OBSS interference. For example, the start times may be the same when the signal strength or interference level associated with the selected AP is relatively low (such as less than a certain value), or when the decoding error rate of the participating AP is relatively low (such as less than a certain threshold). In this way, aspects of the present disclosure may align UL transmissions to or DL transmissions from participating APs with one another in a manner that maximizes medium utilization. Furthermore, aligning UL transmissions to or DL transmissions from participating APs may allow corresponding UL data or DL data to be transmitted using multi-user (MU) multiple-input multiple-output (MIMO) transmission technology.

[0045] Conversely, when the signal strength or interference level associated with the selected AP is relatively high (such as greater than this value), or when the decoding error rate of the participating AP is relatively high (such as greater than this threshold), the start times may be offset from each other by a time period associated with decoding the preamble of the wireless packet and determining whether the wireless packet is an intra-BSS packet or an OBSS packet based on the decoded preamble. For example, the time period between the transmission of the intra-BSS packet and the transmission of the OBSS packet may allow the corresponding AP (or its associated STA) to decode the preamble of the wireless packet and obtain the BSS color value carried in the wireless packet to determine whether the wireless packet is an intra-BSS packet or an OBSS packet. In this way, aspects of the present disclosure can ensure that each of the participating APs and their associated STAs are able to receive and decode intra-BSS packets in the presence of OBSS interference.

[0046] Figure 1 A block diagram of an example wireless communication network 100 is shown. According to some aspects, the wireless communication network 100 may be an example of a wireless local area network (WLAN), such as a Wi-Fi network (and will be referred to as WLAN 100 hereinafter). For example, the WLAN 100 may be a network that implements at least one of the IEEE 802.11 family of standards, such as those defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be. The WLAN 100 may include numerous wireless communication devices, such as an access point (AP) 102 and a plurality of stations (STAs) 104. Although only one AP 102 is shown, the WLAN 100 may also include multiple APs 102.

[0047] Each STA 104 may also be referred to as a mobile station (MS), a mobile device, a mobile handset, a wireless handset, an access terminal (AT), a user equipment (UE), a subscriber station (SS), or a subscriber unit, etc. STA 104 may represent a variety of devices, such as mobile phones, personal digital assistants (PDAs), other handheld devices, netbooks, notebook computers, tablet computers, laptops, display devices (e.g., TVs, computer monitors, navigation systems, etc.), music or other audio or stereo equipment, remote control devices (“remote controls”), printers, kitchen or other home appliances, key fobs (e.g., for passive keyless entry and start (PKES) systems), etc.

[0048] A single AP 102 and the associated set of STAs 104 may be referred to as a basic service set (BSS), which is managed by the corresponding AP 102 . Figure 1 Additionally shown is an example coverage area 106 of an AP 102, which may represent a basic service area (BSA) of the WLAN 100. A BSS may be identified to users by a service set identifier (SSID), and to other devices by a basic service set identifier (BSSID), which may be the media access control (MAC) address of the AP 102. The AP 102 periodically broadcasts beacon frames ("beacons") including the BSSID to enable any STA 104 within wireless range of the AP 102 to "associate" or reassociate with the AP 102 to establish or maintain a corresponding communication link 108 (hereinafter also referred to as a "Wi-Fi link") with the AP 102. For example, the beacon may include an identification of a primary channel used by the respective AP 102 and a timing synchronization function for establishing or maintaining timing synchronization with the AP 102. The AP 102 may provide access to external networks to the various STAs 104 in the WLAN via the corresponding communication links 108.

[0049] To establish a communication link 108 with the AP 102, each STA 104 is configured to perform passive or active scanning operations ("scans") on frequency channels in one or more frequency bands (eg, the 2.4 GHz, 5.0 GHz, 6.0 GHz, or 60 GHz bands). To perform passive scanning, the STA 104 listens for beacons transmitted by the corresponding AP 102 at periodic time intervals, referred to as target beacon transmit times (TBTTs), measured in time units (TUs), where one TU may be equal to 1024 microseconds (μs). To perform active scanning, the STA 104 generates and sequentially transmits probe requests on each channel to be scanned, and listens for probe responses from the AP 102. Each STA 104 may be configured to identify or select an AP 102 with which to associate based on the scan information obtained through passive or active scanning, and perform authentication and association operations to establish a communication link 108 with the selected AP 102. The AP 102 assigns an association identifier (AID) to the STA 104 at the end of the association operation, and the AP 102 uses the association identifier (AID) to track the STA 104.

[0050] As wireless networks become increasingly common, a STA 104 may have the opportunity to select one of many BSSs within range of the STA or multiple APs 102 that together form an extended service set (ESS) (including multiple connected BSSs). Extended network stations associated with a WLAN 100 may be connected to a wired or wireless distribution system that allows multiple APs 102 to be connected in such an ESS. In this way, a STA 104 may be covered by more than one AP 102 and may associate with different APs 102 at different times for different transmissions. Additionally, after associating with an AP 102, the STA 104 may be configured to periodically scan its surroundings to find a more suitable AP 102 with which to associate. For example, a STA 104 that is moving relative to its associated AP 102 may perform a "roaming" scan to find another AP 102 with more favorable network characteristics, such as a greater received signal strength indicator (RSSI) or reduced traffic load.

[0051] In some cases, STAs 104 may form a network without an AP 102 or other equipment other than the STAs 104 themselves. An example of such a network is an ad hoc network (or wireless ad hoc network). An ad hoc network may alternatively be referred to as a mesh network or a peer-to-peer (P2P) network. In some cases, an ad hoc network may be implemented within a larger wireless network, such as WLAN 100. In such an implementation, while STAs 104 may be able to communicate with each other via AP 102 using communication link 108, STAs 104 may also communicate directly with each other via direct communication link 110. Additionally, two STAs 104 may communicate via direct communication link 110 regardless of whether they are associated with and served by the same AP 102. In such an ad hoc system, one or more STAs 104 may assume the role played by AP 102 in a BSS. Such STAs 104 may be referred to as group owners (GOs) and may coordinate transmissions within the ad hoc network. Examples of direct communication link 110 include a Wi-Fi direct connection, a connection established by using a Wi-Fi Tunneled Direct Link Setup (TDLS) link, and other P2P group connections.

[0052] The AP 102 and the STA 104 may operate and communicate (via corresponding communication links 108) in accordance with the IEEE 802.11 family of standards, such as those defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be. These standards define WLAN radio and baseband protocols for the PHY and medium access control (MAC) layers. The AP 102 and the STA 104 send and receive wireless communications (hereinafter also referred to as "Wi-Fi communications") to and from each other in the form of physical layer convergence protocol (PLCP) protocol data units (PPDUs). The AP 102 and STA 104 in the WLAN 100 can send PPDUs on an unlicensed spectrum, which can be a portion of the spectrum that includes frequency bands traditionally used by Wi-Fi technology, such as the 2.4 GHz band, the 5.0 GHz band, the 60 GHz band, the 3.6 GHz band, and the 900 MHz band. Some implementations of the AP 102 and STA 104 described herein can also communicate in other frequency bands, such as the 6.0 GHz band, that can support both licensed and unlicensed communications. The AP 102 and STA 104 can also be configured to communicate in other frequency bands, such as shared licensed bands, where multiple operators may have licenses to operate in one or more of the same or overlapping frequency bands.

[0053] Each of the frequency bands can include multiple sub-bands or frequency channels. For example, PPDUs compliant with IEEE 802.11n, 802.11ac, and 802.11ax standard amendments can be sent in the 2.4 GHz and 5.0 GHz frequency bands, where each frequency band is divided into multiple 20 MHz channels. Thus, these PPDUs are sent on physical channels with a minimum bandwidth of 20 MHz, but larger channels can be formed through channel bonding. For example, a PPDU can be sent on a physical channel with a bandwidth of 40 MHz, 80 MHz, 160 MHz, or 320 MHz by bonding multiple 20 MHz channels together.

[0054] Each PPDU is a composite structure that includes a PHY preamble and a payload in the form of a PLCP service data unit (PSDU). The information provided in the preamble can be used by the receiving device to decode subsequent data in the PSDU. In instances where the PPDU is sent on a bonded channel, the preamble field can be copied and sent in each of the multiple component channels. The PHY preamble may include both a legacy portion (or "legacy preamble") and a non-legacy portion (or "non-legacy preamble"). The legacy preamble can be used for packet detection, automatic gain control, and channel estimation, among other purposes. The legacy preamble can also generally be used to maintain compatibility with legacy devices. The format, decoding, and information provided therein of the non-legacy portion of the preamble are based on the specific IEEE 802.11 protocol to be used to send the payload.

[0055] Figure 2A An example protocol data unit (PDU) 200 is shown that can be used for wireless communication between an AP 102 and one or more STAs 104. For example, the PDU 200 can be configured as a PPDU. As shown, the PDU 200 includes a PHY preamble 202 and a payload 204. For example, the preamble 202 can include a legacy portion that itself includes a legacy short training field (L-STF) 206 that can consist of two BPSK symbols, a legacy long training field (L-LTF) 208 that can consist of two BPSK symbols, and a legacy signal field (L-SIG) 210 that can consist of two BPSK symbols. The legacy portion of the preamble 202 can be configured in accordance with the IEEE 802.11a wireless communication protocol standard. The preamble 202 may also include a non-legacy portion including, for example, one or more non-legacy fields 212 that comply with an IEEE wireless communication protocol, such as IEEE 802.11ac, 802.11ax, 802.11be, or a later wireless communication protocol.

[0056] The L-STF 206 generally enables the receiving device to perform automatic gain control (AGC) and coarse timing and frequency estimation. The L-LTF 208 generally enables the receiving device to perform fine timing and frequency estimation, and can also perform an initial estimate of the wireless channel. The L-SIG 210 generally enables the receiving device to determine the duration of the PDU and use the determined duration to avoid sending over the PDU. For example, the L-STF 206, L-LTF 208, and L-SIG 210 can be modulated according to a binary phase shift keying (BPSK) modulation scheme. The payload 204 can be modulated according to a BPSK modulation scheme, a quadrature BPSK (Q-BPSK) modulation scheme, a quadrature amplitude modulation (QAM) modulation scheme, or another appropriate modulation scheme. The payload 204 may include a PSDU including a data field (DATA) 214, which in turn may carry higher layer data, such as in the form of a medium access control (MAC) protocol data unit (MPDU) or an aggregated MPDU (A-MPDU).

[0057] Figure 2B Shown Figure 2A 2. Example L-SIG 210 in PDU 200. L-SIG 210 includes a data rate field 222, reserved bits 224, a length field 226, parity bits 228, and a tail field 230. Data rate field 222 indicates the data rate (note that the data rate indicated in data rate field 222 may not be the actual data rate of the data carried in payload 204). Length field 226 indicates the packet length, for example, in symbols or bytes. Parity bits 228 can be used to detect bit errors. Tail field 230 includes tail bits that can be used by a receiving device to terminate the operation of a decoder (e.g., a Viterbi decoder). The receiving device can use the data rate and length indicated in data rate field 222 and length field 226 to determine the packet duration, for example, in microseconds (μs) or other time units.

[0058] Figure 3A Another example PDU 300 is shown that can be used for wireless communication between an AP and one or more STAs. PDU 300 can be used for SU, OFDMA, or MU-MIMO transmission. PDU 300 can be formatted as a High-Efficiency (HE) WLAN PPDU in accordance with the IEEE 802.11ax amendment to the IEEE 802.11 wireless communication protocol standard. PDU 300 includes a PHY preamble that includes a legacy portion 302 and a non-legacy portion 304. PDU 300 may also include a payload 306 (e.g., in the form of a PSDU including a data field 324) following the preamble.

[0059] The legacy portion 302 of the preamble includes an L-STF 308, an L-LTF 310, and an L-SIG 312. The non-legacy portion 304 includes a repetition of the L-SIG (RL-SIG) 314, a first HE signal field (HE-SIG-A) 316, a HE short training field (HE-STF) 320, and one or more HE long training fields (or symbols) (HE-LTF) 322. For OFDMA or MU-MIMO communications, the non-legacy portion 304 also includes a second HE signal field (HE-SIG-B) 318 that is encoded separately from the HE-SIG-A 316. As with the L-STF 308, L-LTF 310, and L-SIG 312, in instances involving the use of bonded channels, the information in the RL-SIG 314 and HE-SIG-A 316 may be replicated and transmitted in each component 20 MHz channel. In contrast, the content in the HE-SIG-B 318 may be unique to each 20 MHz channel and target specific STA 104 .

[0060] The RL-SIG 314 may indicate to the HE-compatible STA 104 that the PDU 300 is a HE PPDU. The AP 102 may use the HE-SIG-A 316 to identify multiple STAs 104 and inform them that the AP has scheduled UL or DL resources for them. For example, the HE-SIG-A 316 may include a resource allocation subfield indicating resource allocation for the identified STA 104. The HE-SIG-A 316 may be decoded by each HE-compatible STA 104 served by the AP 102. For MU transmissions, the HE-SIG-A 316 also includes information that can be used by each identified STA 104 to decode the associated HE-SIG-B 318. For example, the HE-SIG-A 316 may indicate the frame format (including the location and length of the HE-SIG-B 318), the available channel bandwidth, and the modulation and coding scheme (MCS), among other examples. The HE-SIG-A 316 may also include HE WLAN signaling information that can be used by STAs 104 other than the identified STA 104.

[0061] The HE-SIG-B 318 may carry STA-specific scheduling information, such as, for example, STA-specific (or "user-specific") MCS values and STA-specific RU allocation information. In the context of DL MU-OFDMA, such information enables the corresponding STA 104 to identify and decode the corresponding resource unit (RU) in the associated data field 324. Each HE-SIG-B 318 includes a common field and at least one STA-specific field. The common field may indicate the RU allocation (including RU assignment in the frequency domain) to multiple STAs 104, indicate which RUs are allocated for MU-MIMO transmission and which RUs correspond to MU-OFDMA transmission, and the number of users in the allocation, among other examples. The common field may be encoded with common bits, CRC bits, and tail bits. The user-specific fields are assigned to a specific STA 104 and may be used to schedule a specific RU and indicate the schedule to other WLAN devices. Each user-specific field may include multiple user block fields. Each user block field may include two user fields containing information for two corresponding STAs to decode their corresponding RU payloads in the data field 324 .

[0062] Figure 3B Another example PPDU 350 is shown that can be used for wireless communication between an AP and one or more STAs. PDU 350 can be used for SU, OFDMA, or MU-MIMO transmission. PDU 350 can be formatted as an Extremely High Throughput (EHT) WLAN PPDU in accordance with the IEEE 802.11be amendment to the IEEE 802.11 wireless communication protocol standard, or can be formatted as a PPDU compliant with any future (post-EHT) version of a new wireless communication protocol (compliant with a future IEEE 802.11 wireless communication protocol standard or other wireless communication standards). PDU 350 includes a PHY preamble that includes a legacy portion 352 and a non-legacy portion 354. PDU 350 may also include a PHY payload 356 (e.g., in the form of a PSDU including a data field 376) following the preamble.

[0063] The legacy portion 352 of the preamble includes an L-STF 358, an L-LTF 360, and an L-SIG 362. The non-legacy portion 354 of the preamble includes an RL-SIG 364 and a plurality of wireless communication protocol version-related signal fields following the RL-SIG 364. For example, the non-legacy portion 354 may include a universal signal field 366 (referred to herein as "U-SIG 366") and an EHT signal field 368 (referred to herein as "EHT-SIG 368"). One or both of the U-SIG 366 and the EHT-SIG 368 may be configured for wireless communication protocol versions other than EHT and carry information related to the version. The non-legacy portion 354 also includes an additional short training field 372 (referred to herein as "EHT-STF 372," but may also be configured to be used for and carry version-related information for wireless communication protocol versions other than EHT) and one or more additional long training fields 374 (referred to herein as "EHT-LTF 374," but may also be configured to be used for and carry version-related information for wireless communication protocol versions other than EHT). As with the L-STF 358, L-LTF 360, and L-SIG 362, in instances involving the use of bonded channels, the information in the U-SIG 366 and EHT-SIG 368 may be replicated and transmitted in each component 20 MHz channel. In some implementations, the EHT-SIG 368 may additionally or alternatively carry different information in one or more non-primary 20 MHz channels than in the primary 20 MHz channel.

[0064] The EHT-SIG 368 may include one or more jointly coded symbols and may be encoded in a different block than the block in which the U-SIG 366 is encoded. The EHT-SIG 368 may be used by the AP to identify multiple STAs 104 and inform them that the AP has scheduled UL or DL resources for them. The EHT-SIG 368 may be decoded by each compatible STA 104 served by the AP 102. The EHT-SIG 368 may generally be used by a receiving device to interpret the bits in the data field 376. For example, the EHT-SIG 368 may include RU allocation information, spatial stream configuration information, and per-user signaling information (such as MCS), among other examples. The EHT-SIG 368 may also include a cyclic redundancy check (CRC) (e.g., four bits) and a tail (e.g., six bits) that may be used for a binary convolutional code (BCC). In some implementations, the EHT-SIG 368 may include one or more code blocks, each including a CRC and a tail. In some aspects, each code block may be encoded separately.

[0065] The EHT-SIG 368 may carry STA-specific scheduling information, such as, for example, user-specific MCS values and user-specific RU allocation information. The EHT-SIG 368 is generally used by a receiving device to interpret the bits in the data field 376. In the context of DL MU-OFDMA, such information enables the corresponding STA 104 to identify and decode the corresponding RU in the associated data field 376. Each EHT-SIG 368 may include a common field and at least one user-specific field. The common field may indicate the RU distribution for multiple STAs 104, the RU assignment in the frequency domain, which RUs are allocated for MU-MIMO transmission and which RUs correspond to MU-OFDMA transmission, and the number of users in the assignment, among other examples. The common field may be encoded with common bits, CRC bits, and tail bits. The user-specific fields are assigned to a specific STA 104 and may be used to schedule specific RUs and indicate this schedule to other WLAN devices. Each user-specific field may include multiple user block fields. Each user block field may include, for example, two user fields containing information for two corresponding STAs to decode their corresponding RU payloads.

[0066] The presence of the RL-SIG 364 and the U-SIG 366 may indicate to the EHT- or later-version compatible STA 104 that the PPDU 350 is an EHT PPDU or a PPDU compliant with any later (post-EHT) version of a new wireless communication protocol (compliant with future IEEE 802.11 wireless communication protocol standards). For example, the U-SIG 366 may be used by a receiving device to interpret bits in one or more of the EHT-SIG 368 or the data field 376.

[0067] Figure 4 An example PPDU 400 is shown that can be used for communication between an AP 102 and several STAs 104. As described above, each PPDU 400 includes a PHY preamble 402 and a PSDU 404. Each PSDU 404 can carry one or more MAC protocol data units (MPDUs), such as, for example, an aggregate MPDU (A-MPDU) 406 including multiple MPDU subframes 408. Each MPDU subframe 408 can include a MAC delimiter 412 and a MAC header 414, preceded by an accompanying frame body 416 (which includes the data portion or "payload" of the MPDU subframe 408). The frame body 416 can carry one or more MAC service data units (MSDUs), such as, for example, an aggregate MSDU (A-MSDU) 422 including multiple MSDU subframes 424. Each MSDU subframe 424 includes a corresponding MSDU 426, which includes a subframe header 428, a frame body 430, and one or more padding bits 432.

[0068] Referring back to the A-MPDU subframe 406, the MAC header 414 may include several fields containing information defining or indicating characteristics or attributes of the data encapsulated within the frame body 416. The MAC header 414 also includes several fields indicating the address for the data encapsulated within the frame body 416. For example, the MAC header 414 may include a combination of a source address, a transmitter address, a receiver address, or a destination address. The MAC header 414 may include a frame control field containing control information. The frame control field specifies the frame type, such as a data frame, a control frame, or a management frame. The MAC header 414 may also include a duration field indicating the duration from the end of the PPDU to the end of the acknowledgement (ACK) (e.g., a block ACK (BA) in the case of an A-MPDU) for the last PPDU to be transmitted by the wireless communication device. The duration field is used to reserve the wireless medium for the indicated duration, thereby establishing a NAV. Each A-MPDU subframe 408 may also include a frame check sequence (FCS) field 418 for error detection. For example, the FCS field 418 may include a cyclic redundancy check (CRC) and may be followed by one or more padding bits 420 .

[0069] As described above, the AP 102 and the STAs 104 may support multi-user (MU) communications. That is, concurrent transmissions from one device to each of multiple devices (e.g., multiple simultaneous downlink (DL) communications from the AP 102 to the corresponding STAs 104), or concurrent transmissions from multiple devices to a single device (e.g., multiple simultaneous uplink (UL) transmissions from the corresponding STAs 104 to the AP 102). To support MU transmissions, the AP 102 and the STAs 104 may utilize multi-user multiple-input multiple-output (MU-MIMO) and multi-user orthogonal frequency division multiple access (MU-OFDMA) technologies.

[0070] In the MU-OFDMA scheme, the available spectrum of a wireless channel can be divided into multiple resource units (RUs), each of which includes several different frequency subcarriers ("tones"). Different RUs can be allocated or assigned to different STAs 104 by the AP 102 at a specific time. The size and distribution of the RUs can be referred to as RU allocation. In some implementations, RUs can be allocated in 2 MHz intervals, and as such, the smallest RU can include 26 tones including 24 data tones and 2 pilot tones. Thus, in a 20 MHz channel, up to 9 RUs (such as 2 MHz, 26-tone RUs) can be allocated (because some tones are reserved for other purposes). Similarly, in a 160 MHz channel, up to 74 RUs can be allocated. Larger RUs of 52 tones, 106 tones, 242 tones, 484 tones, and 996 tones can also be allocated. Adjacent RUs may be separated by nulled subcarriers, such as a DC subcarrier, for example, to reduce interference between adjacent RUs, reduce receiver DC offset, and avoid transmit center frequency leakage.

[0071] For UL MU transmissions, the AP 102 may send a trigger frame to initiate and synchronize UL MU-OFDMA or UL MU-MIMO transmissions from multiple STAs 104 to the AP 102. Such a trigger frame may thereby enable multiple STAs 104 to transmit UL traffic concurrently in time to the AP 102. The trigger frame may address one or more STAs 104 by corresponding association identifiers (AIDs) and may assign one or more RUs to each AID (and thus each STA 104) that may be used to transmit UL traffic to the AP 102. The AP may also specify one or more random access (RA) RUs that unscheduled STAs 104 may contend for.

[0072] Figure 5 1 shows a block diagram of an example wireless communication device 500. In some implementations, the wireless communication device 500 may be a STA (such as the one referenced above) Figure 1 In some implementations, the wireless communication device 500 may be an example of a device in an AP (such as one of the STAs 104 described above). Figure 1The wireless communication device 500 is an example of a device in the described AP 102. The wireless communication device 500 is capable of sending (or outputting for transmission) and receiving wireless communications (e.g., in the form of wireless packets). For example, the wireless communication device 500 can be configured to send and receive packets in the form of physical layer convergence protocol (PLCP) protocol data units (PPDUs) and medium access control (MAC) protocol data units (MPDUs) that comply with the IEEE 802.11 standard (such as the standard defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be).

[0073] The wireless communication device 500 may be or may include a chip, system on chip (SoC), chipset, package, or device that includes one or more modems 502 (e.g., Wi-Fi (IEEE 802.11 compliant) modems). In some implementations, the one or more modems 502 (collectively, “modems 502”) additionally include a WWAN modem (e.g., a 3GPP 4G LTE or 5G compatible modem). In some implementations, the wireless communication device 500 also includes one or more radios 504 (collectively, “radios 504”). In some implementations, the wireless communication device 500 also includes one or more processors, processing blocks, or processing elements (collectively, “processor 506”) and one or more memory blocks or elements (collectively, “memory 508”).

[0074] The modem 502 may include intelligent hardware blocks or devices, such as, for example, an application specific integrated circuit (ASIC) or the like. The modem 502 is generally configured to implement the PHY layer. For example, the modem 502 is configured to modulate packets and output the modulated packets to the radio 504 for transmission over the wireless medium. Similarly, the modem 502 is configured to obtain the modulated packets received by the radio 504 and demodulate the packets to provide demodulated packets. In addition to the modulator and demodulator, the modem 502 may also include digital signal processing (DSP) circuitry, automatic gain control (AGC), a decoder, a decoder, a multiplexer, and a demultiplexer. For example, when in transmit mode, data obtained from the processor 506 is provided to a decoder, which encodes the data to provide coded bits. The coded bits are then mapped to points in the modulation constellation (using the selected MCS) to provide modulated symbols. The modulated symbols can then be mapped to a number N SS spatial streams or the number N STSThe modulated symbols in the corresponding spatial or space-time streams may then be multiplexed, transformed via an inverse fast Fourier transform (IFFT) block, and then provided to the DSP circuitry for Tx windowing and filtering. The digital signal may then be provided to a digital-to-analog converter (DAC). The resulting analog signal may then be provided to an upconverter and ultimately to the radio 504. In specific implementations involving beamforming, the modulated symbols in the corresponding spatial streams may be pre-coded via a steering matrix before being provided to the IFFT block.

[0075] When in receive mode, a digital signal received from radio 504 is provided to a DSP circuit configured to acquire the received signal, for example, by detecting the presence of a signal and estimating initial timing and frequency offset. The DSP circuit is further configured to digitally condition the digital signal, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correcting I / Q imbalance), and applying digital gain to ultimately obtain a narrowband signal. The output of the DSP circuit can then be fed to an AGC, which is configured to use information extracted from the digital signal (e.g., in one or more received training fields) to determine an appropriate gain. The output of the DSP circuit is also coupled to a demodulator, which is configured to extract the modulated symbols from the signal and, for example, calculate a log-likelihood ratio (LLR) for each bit position of each subcarrier in each spatial stream. The demodulator is coupled to a decoder, which can be configured to process the LLRs to provide decoded bits. The decoded bits from all spatial streams are then fed to a demultiplexer for demultiplexing. The demultiplexed bits may then be descrambled and provided to the MAC layer (processor 506) for processing, evaluation, or interpretation.

[0076] The radio 504 generally includes at least one radio frequency (RF) transmitter (or "transmitter chain") and at least one RF receiver (or "receiver chain"), which can be combined into one or more transceivers. For example, the RF transmitter and receiver can include various DSP circuits, including at least one power amplifier (PA) and at least one low noise amplifier (LNA), respectively. The RF transmitter and receiver can, in turn, be coupled to one or more antennas. For example, in some implementations, the wireless communication device 500 can include or be coupled to multiple transmit antennas (each with a corresponding transmit chain) and multiple receive antennas (each with a corresponding receive chain). The symbols output from the modem 502 are provided to the radio 504, which then transmits the symbols via the coupled antennas. Similarly, the symbols received via the antennas are obtained by the radio 504, which then provides the symbols to the modem 502.

[0077] The processor 506 may comprise an intelligent hardware block or device designed to perform the functions described herein, such as a processing core, a processing block, a central processing unit (CPU), a microprocessor, a microcontroller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD) (such as a field-programmable gate array (FPGA)), discrete gate or transistor logic components, discrete hardware components, or any combination thereof. The processor 506 processes information received via the radio 504 and the modem 502, and processes information to be output by the modem 502 and the radio 504 for transmission over the wireless medium. For example, the processor 506 may implement the control plane and MAC layer, which are configured to perform various operations related to the generation and transmission of MPDUs, frames, or packets. The MAC layer is configured to perform or facilitate frame coding and decoding, spatial multiplexing, space-time block coding (STBC), beamforming, and OFDMA resource allocation, among other operations or techniques. In some implementations, the processor 506 may generally control the modem 502 to cause it to perform the various operations described above.

[0078] The memory 508 may include a tangible storage medium such as a random access memory (RAM) or a read-only memory (ROM) or a combination thereof. The memory 508 may also store non-transitory processor or computer executable software (SW) code containing instructions that, when executed by the processor 506, cause the processor to perform various operations for wireless communication described herein, including the generation, transmission, reception, and interpretation of MDPUs, frames, or packets. For example, the various functions of the various components disclosed herein or the various blocks or steps of the methods, operations, processes, or algorithms disclosed herein may be implemented as one or more modules of one or more computer programs.

[0079] Figure 6A FIG shows a block diagram of an example AP 602. For example, the AP 602 may be a reference Figure 1 The example implementation of the AP 102 is described. The AP 602 includes a wireless communication device (WCD) 610. For example, the wireless communication device 610 may be a reference Figure 5An example implementation of the wireless communication device 500 is described. AP 602 also includes multiple antennas 620 coupled to the wireless communication device 610 for transmitting and receiving wireless communications. In some implementations, AP 602 additionally includes an application processor 630 coupled to the wireless communication device 610 and a memory 640 coupled to the application processor 630. AP 602 also includes at least one external network interface 650 that enables AP 602 to communicate with a core network or a backhaul network to gain access to an external network, including the Internet. For example, external network interface 650 may include one or both of a wired (e.g., Ethernet) network interface and a wireless network interface (such as a WWAN interface). Components of the aforementioned components may communicate directly or indirectly with other components of the components via at least one bus. AP 602 also includes a housing that encloses the wireless communication device 610, application processor 630, memory 640, and at least portions of antennas 620 and external network interface 650.

[0080] Figure 6B 604. For example, STA 604 may be a reference Figure 1 The example implementation of the STA 104 is described. The STA 604 includes a wireless communication device 615. For example, the wireless communication device 615 may be a reference Figure 5 An example implementation of the wireless communication device 500 is described. STA 604 also includes one or more antennas 625 coupled to the wireless communication device 615 for transmitting and receiving wireless communications. STA 604 additionally includes an application processor 635 coupled to the wireless communication device 615 and a memory 645 coupled to the application processor 635. In some implementations, STA 604 also includes a user interface (UI) 655 (such as a touch screen or keyboard) and a display 665, which can be integrated with the UI 655 to form a touch screen display. In some implementations, STA 604 can also include one or more sensors 675 (such as, for example, one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors). Components of the aforementioned components can communicate directly or indirectly with other components of the components via at least one bus. STA 604 also includes a housing that encloses the wireless communication device 615, the application processor 635, the memory 645, and at least portions of the antenna 625, the UI 655, and the display 665.

[0081] As described above, various embodiments generally relate to sharing resources of a wireless medium with a group of wireless communication devices, regardless of which wireless communication device is the owner of a TXOP on the wireless medium. More specifically, some embodiments relate to a first AP associated with a first BSS sharing some or all of an acquired TXOP on the wireless medium with other APs associated with an OBSS operating independently of the first BSS. In some embodiments, the first AP may select one or more of the other APs to participate in a coordinated access point transmission session, during which the first AP shares at least a portion of the TXOP with the one or more selected APs for UL transmissions to or DL transmissions from the participating APs. After acquiring the TXOP on the wireless medium, the first AP may send a frame to the one or more selected APs indicating scheduling information for UL transmissions to or DL transmissions from each of the selected APs during a specified portion of the TXOP acquired by the first AP. The scheduling information may be based on one or more of signal strength of wireless packets received from the selected AP, interference levels associated with the selected AP, decoding error rates of the first AP and the selected AP, or wireless resources requested by the selected AP.

[0082] During a coordinated access point transmission session, a first AP may, based on scheduling information, transmit or receive one or more wireless packets to or from one or more STAs associated with the corresponding selected APs at least partially concurrently with the transmission of one or more wireless packets to or from one or more STAs associated with the first AP. In some implementations, the scheduling information indicates a start time for UL or DL transmissions to or from each of the selected APs during at least a portion of a TXOP obtained by the first AP. In some instances, the start times may be the same. In other instances, the start times may be offset by a period of time. In some aspects, the period of time may be based on an amount of time associated with a participating AP decoding a preamble of a wireless packet and determining, based on the decoded preamble, whether the wireless packet is an intra-BSS packet or an OBSS packet.

[0083] Certain implementations of the subject matter described in this disclosure can be implemented to achieve one or more of the following potential advantages. By allowing a group of APs associated with different BSSs or associated with different BSSs to participate in a coordinated access point transmission session, during which the group of APs can share at least a portion of the TXOP obtained by any of the participating APs, aspects of the present disclosure can increase the throughput of the wireless medium across all of the BSSs associated with the participating APs. Furthermore, by scheduling UL transmissions to or DL transmissions from participating APs at start times that can be the same or offset by a certain period of time, aspects of the present disclosure can maximize medium utilization while also minimizing packet loss due to OBSS interference. For example, the start times can be the same when the signal strength or interference level associated with the selected AP is relatively low (such as less than a certain value), or when the decoding error rate of the participating AP is relatively low (such as less than a certain threshold). In this way, aspects of the present disclosure can align UL transmissions to or DL transmissions from participating APs in a manner that maximizes medium utilization. Furthermore, aligning UL transmissions to or DL transmissions from participating APs may allow corresponding UL data or DL data to be transmitted using multi-user (MU) multiple-input multiple-output (MIMO) transmission technology.

[0084] Conversely, when the signal strength or interference level associated with the selected AP is relatively high (such as greater than this value), or when the decoding error rate of the participating AP is relatively high (such as greater than this threshold), the start times may be offset from each other by a time period associated with decoding the preamble of the wireless packet and determining whether the wireless packet is an intra-BSS packet or an OBSS packet based on the decoded preamble. For example, the time period between the transmission of the intra-BSS packet and the transmission of the OBSS packet may allow the corresponding AP (or its associated STA) to decode the preamble of the wireless packet and obtain the BSS color value carried in the wireless packet to determine whether the wireless packet is an intra-BSS packet or an OBSS packet. In this way, aspects of the present disclosure can ensure that each of the participating APs and their associated STAs are able to receive and decode intra-BSS packets in the presence of OBSS transmissions associated with other participating APs.

[0085] Figure 7AA timing diagram of an example wireless communication 700A supporting coordinated spatial reuse of UL transmissions according to some implementations is shown. The wireless communication 700A is shown to include a first AP (AP1), a second AP (AP2), and a third AP (AP3). Each of AP1, AP2, and AP3 can be any suitable access point, access terminal, or peer-to-peer (P2P) device capable of operating a basic service set (BSS) on a wireless medium, such as a soft AP. In some implementations, each of AP1, AP2, and AP3 can be a Figure 1 AP 102 or Figure 6A 7 , one embodiment of an AP 602. In some examples, AP1 may belong to or be associated with a first BSS, AP2 may belong to or be associated with a second BSS, and AP3 may belong to or be associated with a third BSS, where the first BSS, the second BSS, and the third BSS are different from each other. Although not shown in FIG. 7 for simplicity, one or more wireless stations (STAs) may be associated with each of AP1, AP2, and AP3.

[0086] In some implementations, AP1, AP2, and AP3 may be located near one another such that their wireless coverage areas at least partially overlap. For example, in some instances, AP1, AP2, and AP3 may operate independent BSSs within the same home, business, building, etc., and may benefit from sharing wireless resources with one another in a coordinated manner. In some aspects, AP1, AP2, and AP3 may be associated with the same entity or controlled by the same administrator. In some implementations, AP1, AP2, and AP3 may be connected to one another via a backhaul connection, over which capabilities, resource allocations, scheduling information, and other data may be exchanged between AP1, AP2, and AP3. When the wireless coverage areas of AP1, AP2, and AP3 overlap or are within a threshold distance of one another, wireless transmissions associated with one of the BSSs may interfere with wireless transmissions associated with the other BSSs. Thus, the BSS operated by AP1, AP2, and AP3 may be an OBSS.

[0087] Figure 7AThe coordinated access point transmission session depicted in wireless communication 700A may include a resource polling phase 705, a scheduling phase 710, and a transmission phase 720. The resource polling phase 705 may be used to identify nearby APs and select one or more of the identified APs to participate in the coordinated access point transmission session. The scheduling phase 710 may be used to allocate wireless resources to the selected APs and determine or obtain scheduling information for UL transmissions to the selected APs during the coordinated access point transmission session. For example, the transmission phase 720 may be used to share a portion of the TXOP obtained by AP1 with the selected APs so that each of the APs can receive UL transmissions from their associated STAs during the coordinated access point transmission session.

[0088] In some implementations, the resource polling phase 705 may begin at time t0, with AP1 sending a polling frame over the wireless medium to nearby APs, such as AP2 and AP3. The polling frame (which may be any suitable polling frame, action frame, control frame, or management frame) may announce or otherwise indicate the presence of a coordinated access point transmit session on the wireless medium. In some examples, the polling frame may request each receiving AP to indicate whether the receiving AP intends to participate in the coordinated access point transmit session. The polling frame may also solicit a request for wireless resources from each of the receiving APs.

[0089] One or more of the receiving APs (such as AP2 and AP3) receive the polling frame and determine whether to participate in the coordinated access point transmission session. Figure 7A In the example shown in FIG2 , AP2 and AP3 signal their intent to participate in a coordinated access point transmission session by sending response frames to AP1 over the wireless medium between times t2 and t3. The response frames may indicate the operational capabilities of AP2 and AP3 and may include a request for wireless resources for UL transmissions during the coordinated access point transmission session. In some instances, the response frames may request an allocation of time and frequency resources from the respective APs. In other instances, the response frames may request that AP1 share a specific portion or duration of a TXOP acquired by AP1 with the respective APs.

[0090] AP1 receives the response frames transmitted by AP2 and AP3 and may use the information carried in the response frames to determine or select which APs to admit as participants in the coordinated access point transmission session. AP1 may also use the information carried in the response frames to allocate time and frequency resources to participating APs, determine or select the portion of the TXOP to be shared with participating APs, and determine or obtain scheduling information for UL transmissions to participating APs. Figure 7A In the example of FIG, resource polling phase 705 ends at time t4.

[0091] Between time t4 and t5, AP1 obtains a TXOP on the wireless medium. In some implementations, AP1 may sense that the wireless medium is idle for a certain period of time based on a channel sensing operation, such as a clear channel assessment (CCA), before contending for channel access. In some instances, AP1 may sense that the wireless medium is idle for a duration of PIFS before attempting to gain channel access. In some other instances, AP1 may sense that the wireless medium is idle for a duration of DIFS before attempting to gain channel access.

[0092] In some implementations, the scheduling phase 710 may begin at time t5, with AP1 transmitting a spatial reuse (SR) start frame to AP2 and AP3 over the wireless medium. The SR start frame may identify AP2 and AP3, may indicate an allocation of wireless resources to a second BSS and a third BSS (operated by AP2 and AP3, respectively) during the coordinated access point transmission session, and may include scheduling information for UL transmissions to AP2 and AP3 during the coordinated access point transmission session. In some aspects, the SR start frame may also include instructions for AP2 and AP3 to retransmit the scheduling information and resource allocation indicated in the SR start frame to their associated STAs in one or more scheduled frames. In some instances, the scheduling information may indicate a start time for UL transmissions to each of the participating APs. In some other instances, the scheduling information may also indicate one or more of an MCS to be used for UL transmissions to the participating APs, a transmit power level to be used for UL transmissions to the participating APs, or a duration for UL transmissions to the participating APs. In some other examples, the scheduling information may also indicate a transmit power limit and / or an allowable interference level for each of the participating APs.

[0093] AP2 and AP3 receive the SR Start frame and may decode the SR Start frame to obtain the scheduling information and resource allocation provided by AP1. In some examples, each of AP2 and AP3 may send a Clear to Send (CTS) frame over the wireless medium to acknowledge receipt of the SR Start frame and reserve the wireless medium. In other examples, AP2 and AP3 may not send a frame in response to the SR Start frame.

[0094] In some examples, at time t7, AP1, AP2, and AP3 may transmit a scheduling frame to their associated STAs via the wireless medium. The scheduling frame may include the same information carried in the SR Start frame (such as, but not limited to, scheduling information and resource allocation), for example, to ensure that all of the STAs associated with AP2 and AP3 obtain the scheduling information and resource allocation before the start of the transmission phase 720. For example, although AP2 and AP3 may be within the wireless range of AP1 and able to receive and decode the SR Start frame, some of the STAs associated with AP2 or AP3 (or both) may not be within the wireless range of AP1 and, therefore, may not be able to receive or decode the SR Start frame transmitted by AP1. In this way, STAs associated with AP2 may obtain resource allocation and scheduling information from the scheduling frame transmitted by AP2, and STAs associated with AP3 may obtain resource allocation and scheduling information from the scheduling frame transmitted by AP3.

[0095] In some implementations, the scheduling frames can be identical to each other and carry the same information as the SR start frame. For example, the scheduling frames can have the same format and the same transmission duration, can be sent using the same MCS, etc. In this way, the transmission of the scheduling frames from the corresponding AP can have minimal (if any) impact on the transmission of scheduling frames from other APs participating in the coordinated access point transmission session.

[0096] In some instances, the schedule frame may be transmitted over the wireless medium as multiple identical non-HT replica PPDUs. For example, the schedule frame may be formatted for transmission on a 20 MHz subchannel, replicated N times, and transmitted as N replicas across an N x 20 MHz bandwidth (where N is an integer greater than 1). In other aspects, the schedule frame may be formatted for transmission on a wider subchannel, such as a 40 MHz or 80 MHz subchannel. Concurrent transmission of non-HT replicas carrying the same scheduling information and the same resource allocations on multiple different subchannels may allow STAs associated with participating APs to receive the schedule frame and obtain the scheduling information and resource allocations carried therein, regardless of the specific subchannel on which the associated STAs may operate. STAs associated with AP1, AP2, and AP3 receive the schedule frame between times t8 and t9 and obtain the scheduling information and resource allocations indicated in the SR Start frame.

[0097] In some other instances, for example, when STAs associated with AP2 and AP3 can obtain scheduling information and resource allocation provided by AP1 from the SR start frame, AP1, AP2, and AP3 may not send a scheduling frame. In such instances, the transmission phase 720 may start at time t7 (instead of Figure 7A at time t9).

[0098] In some implementations, the sending phase 720 may begin at time t9, where AP1 sends the data between time t9 and t 10 1 and AP3 over the wireless medium. The trigger frames may identify AP2 and AP3 and may allocate time and frequency resources to the respective BSSs operated by AP2 and AP3 for UL transmissions from one or more STAs associated with the respective BSSs. The trigger frames may be any suitable trigger frames, including but not limited to basic trigger frames or MU-RTS trigger frames. In some examples, AP2 may send a trigger frame to its associated STAs over the wireless medium at time t9, and AP3 may send a trigger frame to its associated STAs over the wireless medium at time t9. The trigger frame sent by AP2 may include scheduling information and resource allocations for the STAs associated with AP2, and the trigger frame sent by AP3 may include scheduling information and resource allocations for the STAs associated with AP3. In some other implementations, AP1, AP2, and AP3 may not send trigger frames, and the transmission phase 720 may begin by sending UL data 701, 702, and 703 to AP1, AP2, and AP3, respectively.

[0099] At time t 11 With t 12 , one or more STAs associated with a first BSS transmit UL data 701 to AP1 via a wireless medium, one or more STAs associated with a second BSS transmit UL data 702 to AP2 via a wireless medium, and one or more STAs associated with a third BSS transmit UL data 703 to AP3 via a wireless medium. In some instances, the UL data transmissions to AP1, AP2, and AP3 may begin simultaneously (such as by having the same start time). In other instances, the UL data transmissions to AP1, AP2, and AP3 may be offset from each other by a certain period of time. In some aspects, the period of time may be based on an amount of time associated with determining whether a wireless packet detected on the wireless medium is an intra-BSS packet or an OBSS packet.

[0100] Each of AP1, AP2, and AP3 receives an UL transmission from their respective associated STA and can be accessed by 13 ACKs are sent to their respective associated STAs to indicate their successful reception. These ACKs can be ACK (Acknowledgement) frames, Block Acknowledgement (BA) frames, or some other suitable frames. Figure 7A It is shown as a BA frame for illustration purposes only.

[0101] STAs associated with the first BSS, the second BSS, and the third BSS at time t 13 With t 14In some examples, the sending phase 720 receives BA frames from AP1, AP2, and AP3 at time t. 14 ends, and the TXOP obtained by AP1 is completed at time t 15 In other examples, the TXOP obtained by AP1 may extend beyond time t 15 , and the sending phase 720 may extend beyond time t 14 .

[0102] Figure 7B A timing diagram illustrating an example wireless communication 700B supporting coordinated spatial reuse of DL transmissions according to some implementations is shown. The wireless communication 700B is shown to include reference Figure 7A The wireless communication 700B is similar to the AP1, AP2 and AP3 described above. Figure 7A The wireless communication 700A is different in that Figure 7B The depicted coordinated access point transmission session is designated for DL transmissions from AP1, AP2, and AP3. In some instances, the resource polling phase 705 and the scheduling phase 710 shown in the example wireless communication 700B are similar to the reference 700B. Figure 7A The polling phase 705 and the scheduling phase 710 are described.

[0103] The transmission phase 720 may begin at time t7, where AP1 transmits DL data 721 to one or more STAs associated with the first BSS, AP2 transmits DL data 722 to one or more STAs associated with the second BSS, and AP3 transmits DL data 723 to one or more STAs associated with the third BSS. In some examples, the DL data transmissions from AP1, AP2, and AP3 may begin simultaneously, e.g., Figure 7B In other examples, the DL data transmissions from AP1, AP2, and AP3 may be offset from each other by a certain period of time. In some examples, the DL data transmissions from AP1, AP2, and AP3 may end concurrently at time t8, as shown in FIG. Figure 7B In other examples, the DL data transmissions from AP1, AP2, and AP3 may end at different times.

[0104] Between time t7 and t8, one or more STAs associated with the first BSS receive DL data 721 from AP1, one or more STAs associated with the second BSS receive DL data 722 from AP2, and one or more STAs associated with the third BSS receive DL data 723 from AP3. At time t9, the STAs associated with AP1, AP2, and AP3 may indicate the successful reception of the corresponding DL data 721, 722, and 723 by sending acknowledgments to their respective APs. These acknowledgments may be ACK frames, BA frames, or other suitable frames capable of indicating which portions of the DL data were successfully decoded by the respective STAs and which portions of the DL data were not received or were not successfully decoded by the respective STAs. These acknowledgments may be received by the respective STAs at the time t9. Figure 7A It is shown as a BA frame for illustration purposes only.

[0105] AP1, AP2 and AP3 can be connected at time t9 and t 10 In some instances, the transmission phase 720 receives BA frames from their respective associated STAs at time t 10 ends, and the TXOP obtained by AP1 is completed at time t 11 In other examples, the TXOP obtained by AP1 may extend beyond time t 11 , and the sending phase 720 may extend beyond time t 10 .

[0106] Figure 8 A timing diagram of another example wireless communication 800 supporting coordinated spatial reuse of DL transmissions according to some implementations is shown. The wireless communication 800 is shown to include reference Figure 7A and Figure 7B In some implementations, the wireless communication 800 may be Figure 7B For example, in some aspects, Figure 8 The resource polling phase (not shown for simplicity) and the scheduling phase 810 of the example are similar to those of reference 1 and reference 2, respectively. Figure 7A and Figure 7B The polling phase 705 and the scheduling phase 710 are described. Figure 8 In the example shown in Figure 2, the scheduling information carried in the SR Start frame indicates that DL transmissions from AP1, AP2, and AP3 start simultaneously and have the same transmission duration. Thus, DL transmissions from AP1, AP2, and AP3 can be aligned in time because they all have the same start time and the same end time.

[0107] The transmission phase 820 may begin at time t2, wherein AP1 transmits a DL PPDU 801 to one or more STAs associated with a first BSS between time t2 and t4, wherein AP2 transmits a DL PPDU 802 to one or more STAs associated with a second BSS between time t2 and t4, and wherein AP3 transmits a DL PPDU 803 to one or more STAs associated with a third BSS between time t2 and t4. Specifically, the concurrent transmissions of the DL PPDU 801, the DL PPDU 802, and the DL PPDU 803 have the same start time, the same transmission duration, and the same end time. Although for simplicity, Figure 8 The example shows that AP1, AP2, and AP3 transmit a single DL PPDU during the transmission phase 820, but in some other implementations, each of AP1, AP2, and AP3 may transmit multiple DL PPDUs to their associated STAs during the transmission phase 820.

[0108] One or more STAs associated with AP1 receive DL PPDU 801 and indicate successful reception of DL PPDU 801 by sending an acknowledgment to AP1 at time t5. Similarly, one or more STAs associated with AP2 indicate successful reception of DL PPDU 802 by sending an acknowledgment to AP2 at time t5, and one or more STAs associated with AP3 indicate successful reception of DL PPDU 803 by sending an acknowledgment to AP3 at time t5. As discussed, these acknowledgments can be any suitable frames (such as ACK frames or BA frames) that can indicate which portions of the DL data transmission were successfully decoded by the respective STAs and which portions of the DL data transmission were not successfully decoded.

[0109] Acknowledgements transmitted by one or more STAs associated with the first, second, and third BSSs may be received by AP1, AP2, and AP3 at time t6. Figure 8 8. The TXOP obtained by AP1 may be extended beyond time t7, and the TXOP obtained by AP1 may be extended beyond time t6.

[0110] As discussed, the transmission of DL PPDUs 801-803 is aligned in time with one another and, therefore, may be suitable for transmission using MU-MIMO. Alignment of DL PPDUs 801-803 may also increase medium utilization and data throughput during the transmission phase 820. In some instances, aligning DL PPDUs 801-803 with one another may allow OBSS transmissions associated with the second or third BSS to interfere with the ability of STAs associated with AP1 to detect and successfully decode DL PPDU 801 (or other packets or frames associated with the first BSS). For example, if the signal strength of DL PPDU 802 at a respective STA is greater than the level at the respective STA and DL PPDU 802 arrives at the respective STA slightly earlier than DL PPDU 801, the respective STA may detect DL PPDU 802 transmitted from AP2 rather than DL PPDU 801 transmitted from AP1 and lock onto the DL PPDU transmitted from AP2. The STA may decode the fields and subfields of the preamble of the DL PPDU 802 until the STA obtains an indication of the BSS associated with the DL PPDU 802. In some aspects, the STA may decode the preamble of the DL PPDU 802 until the BSS color value carried in the preamble is obtained. The STA may use the obtained BSS color value to determine whether the DL PPDU 802 is an intra-BSS packet or an OBSS packet.

[0111] For instances where the STA determines that the DL PPDU 802 is an OBSS packet transmitted from another participating AP, the STA may discard the DL PPDU 802 and listen to the wireless medium for intra-BSS transmissions (such as DL PPDU 801). Aspects of the present disclosure recognize that because the preambles of the DL PPDUs 801-803 are aligned in time with each other, the STA may miss the preamble of the DL PPDU 802 when decoding the preamble of the DL PPDU 801 and, therefore, may fail to receive the data carried in the DL PPDU 801 from AP1 in the presence of OBSS interference from AP2. In some implementations, the likelihood of the STA (and other STAs associated with AP1) missing the intra-BSS packet when decoding the preamble of the OBSS packet can be reduced (or eliminated) by offsetting the transmissions of the DL PPDUs 801-803 from each other by a certain period of time, as described with reference to FIG. Figure 9A described.

[0112] Figure 9A A timing diagram illustrating an example wireless communication 900A supporting coordinated spatial reuse of DL transmissions according to some other implementations is shown. The wireless communication 900A is shown to include reference Figure 7A 、 Figure 7B and Figure 8 In some implementations, wireless communication 900A may be Figure 7B Another example of wireless communication 700B. In some aspects, Figure 9A The resource polling phase and the scheduling phase 910 are similar to those of reference Figure 8 The polling phase and scheduling phase 810 are described with at least one notable exception (for simplicity, Figure 9A The resource polling phase is not shown in ). For example, in Figure 8 The scheduling information carried in the SR start frame indicates that the start time of DL transmission from AP1 to AP3 is the same, while Figure 9A The scheduling information carried in the SR start frame indicates that the start times of DL transmissions from AP1 to AP3 are offset from each other by a certain period of time.

[0113] Scheduling phase 910 begins at time t0, with AP1 sending an SR Start frame to AP2 and AP3 over the wireless medium. As discussed, the SR Start frame may indicate scheduling information and resource allocations for DL transmissions associated with participating APs. Each of AP2 and AP3 receives the SR Start frame and obtains the DL transmission start time and resource allocation indicated by AP1.

[0114] The transmission phase 920 begins at time t2, where AP1 transmits a DL PPDU 901 to one or more STAs associated with the first BSS. At time t3, AP2 begins transmitting a DL PPDU 902 to one or more STAs associated with the second BSS. At time t4, AP3 begins transmitting a DL PPDU 903 to one or more STAs associated with the third BSS. Thus, the start of transmission of the DL PPDU 902 to the STAs associated with the second BSS is offset by a certain period of time relative to the start of transmission of the DL PPDU 901 to the STAs associated with the first BSS. Similarly, the start of transmission of the DL PPDU 903 to the STAs associated with the third BSS is offset by a certain period of time relative to the start of transmission of the DL PPDU 902 to the STAs associated with the second BSS. Although for simplicity, Figure 9A The example shows that AP1, AP2, and AP3 transmit a single DL PPDU during the transmission phase 920, but in some other implementations, each of AP1, AP2, and AP3 may transmit multiple DL PPDUs to their associated STAs during the transmission phase 920.

[0115] In some examples, the time offset between time t2 and t3 may allow a STA associated with a first BSS to detect DL PPDU 901, decode the preamble, and use the decoded preamble to determine that DL PPDU 901 is an intra-BSS packet that may be intended for one or more STAs associated with the first BSS. Additionally, the time offset between time t2 and t3 may allow a STA associated with a second BSS that receives DL PPDU 901 from AP1 to determine that DL PPDU 901 is an OBSS packet and discard DL PPDU 902 before transmitting DL PPDU 901 from AP2. Similarly, the time offset between time t3 and t4 may allow a STA associated with a second BSS to detect DL PPDU 902, decode the preamble, and use the decoded preamble to determine that DL PPDU 902 is an intra-BSS packet that may be intended for one or more STAs associated with the second BSS. Additionally, the time offset between times t3 and t4 may allow a STA associated with a third BSS that receives the DL PPDU 902 from AP2 to determine that the DL PPDU 902 is an OBSS packet and discard the packet before sending the DL PPDU 903 from AP3.

[0116] In some implementations, the length or duration of one or more of the DL PPDUs 901-903 can be selectively adjusted or configured so that the transmission of the corresponding DL PPDUs 901-903 ends at the same time. For example, in some instances, the transmission duration d1 of the DL PPDU 901 can be configured or adjusted so that the transmission of the DL PPDU 901 ends at time t6. Similarly, the transmission duration d2 of the DL PPDU 902 can be configured or adjusted so that the transmission of the DL PPDU 902 also ends at time t6, and the transmission duration d3 of the DL PPDU 903 can be configured or adjusted so that the transmission of the DL PPDU 903 also ends at time t6.

[0117] In some examples, aligning the transmission end times of DL PPDUs 901-903 can cause STAs that receive DL PPDUs 901-903 to simultaneously send acknowledgments to their respective APs. For example, STAs associated with each of the first, second, and third BSSs can send acknowledgments to their respective APs some time after time t6. In some examples, STAs associated with AP1, AP2, and AP3 send BA frames 941-943 to their respective APs at time t7, which occurs a SIFS duration after time t6. BA frames 941-943 can be received by AP1-AP3, respectively, at time t8. In some examples, the transmission phase 920 ends at time t8, and the TXOP obtained by AP1 ends at time t9. In other examples, the TXOP obtained by AP1 may extend beyond time t9, and the transmission phase 920 may extend beyond time t8.

[0118] Aligning the transmission of BA frames 941-943 with one another may allow OBSS transmissions associated with the second or third BSS to interfere with AP1's ability to detect or receive BA frame 941 transmitted by its associated STA. For example, if the signal strength of BA frame 942 at AP1 is greater than a certain level, AP1 may detect BA frame 942 transmitted by the STA associated with the second BSS, rather than BA frame 941 transmitted by the STA associated with the first BSS, and lock onto the BA frame transmitted by the STA associated with the second BSS. In some examples, AP1 may decode fields and subfields of the preamble of BA frame 942 until an indication of the BSS associated with BA frame 942 is obtained. In some aspects, AP1 may decode the preamble of BA frame 942 until a BSS color value carried in the preamble of BA frame 942 is obtained. AP1 may use the obtained BSS color value or some other indication of the BSS, such as a MAC address, to determine whether BA frame 942 is an intra-BSS packet or an OBSS packet.

[0119] After determining that the BA frame 942 is an OBSS packet, AP1 may discard the BA frame 942 and begin listening on the wireless medium for BA frames sent from its associated STAs. In some instances, when AP1 begins listening to the wireless medium again, the preamble of the BA frame 941 may have already been sent over the wireless medium, which in turn may cause AP1 to incorrectly conclude that its associated STA did not send any acknowledgment in response to receiving the DL PPDU 901.

[0120] In some specific implementations, such as reference Figure 9BAs described, the likelihood of a respective AP missing a BA frame transmitted from its associated STA when decoding a preamble of a BA frame associated with another BSS can be reduced (or eliminated) by offsetting the respective transmissions of the BA frames 941-943 relative to each other by a certain period of time.

[0121] Figure 9B A timing diagram of another example wireless communication 900B supporting coordinated spatial reuse of DL transmissions according to some other implementations is shown. The wireless communication 900B is shown to include reference Figure 7A 、 Figure 7B and Figure 8 In some implementations, wireless communication 900B may be Figure 7B Another example of wireless communication 700B. In some aspects, Figure 9B The resource polling phase and the scheduling phase 910 are similar to those of reference Figure 7B The polling phase 705 and the scheduling phase 710 are described (for simplicity, Figure 9B The resource polling phase is not shown).

[0122] The transmission phase 920 begins at time t2, where AP1 transmits a DL PPDU 911 to one or more STAs associated with the first BSS. At time t3, which is offset by a certain period of time from time t2, AP2 transmits a DL PPDU 912 to one or more STAs associated with the second BSS. At time t4, which is offset by the same period of time from time t3, AP3 transmits a DL PPDU 913 to one or more STAs associated with the third BSS. Although for simplicity, Figure 9B The example shows that AP1, AP2, and AP3 transmit a single DL PPDU during the transmission phase 920, but in some other implementations, each of AP1, AP2, and AP3 may transmit multiple DL PPDUs to their associated STAs during the transmission phase 920.

[0123] exist Figure 9BIn the example of , the length or duration of one or more of the DL PPDUs 911-913 can be selectively adjusted or configured so that their respective transmission durations d1, d2, and d3 are the same as each other. For example, in some instances, the transmission duration d1 of the DL PPDU 911 can be configured or adjusted so that the transmission of the DL PPDU 911 ends at time t6, the transmission duration d2 of the DL PPDU 912 can be configured or adjusted so that the transmission of the DL PPDU 912 ends at time t7 (which is offset from time t6 by the time period), and the transmission duration d3 of the DL PPDU 913 can be configured or adjusted so that the transmission of the DL PPDU 913 ends at time t8 (which is offset from time t7 by the time period).

[0124] In some aspects, offsetting the end time of transmission of the DL PPDUs 911-913 by the time period causes the start times of transmission of acknowledgements of the DL PPDUs 911-913 to be offset from each other by the time period. For example, a STA associated with a first BSS may transmit a BA frame 951 to AP1 after a SIFS duration from the end of the DL PPDU 911, a STA associated with a second BSS may transmit a BA frame 952 to AP2 after a SIFS duration from the end of the DL PPDU 912, and a STA associated with a third BSS may transmit a BA frame 953 to AP3 after a SIFS duration from the end of the DL PPDU 913, wherein the transmission of BA frame 952 is offset from the transmission of BA frame 951 by the time period, and the transmission of BA frame 953 is offset from the transmission of BA frame 952 by the time period. BA frames 951-953 may be received by AP1-AP3, respectively, at times offset from each other by the time period.

[0125] In some implementations, the time period between the transmission start times of the respective BA frames 951-953 can be the same as the time period between the transmission start times of the DL PPDUs 911-913. For example, the time period between the transmission start time of BA frame 951 and the transmission start time of BA frame 952 can be the same as the time period between time t2 and t3, and the time period between the transmission start time of BA frame 952 and the transmission start time of BA frame 953 can be the same as the time period between time t3 and t4. By using the same timing offset between the transmission start times of BA frames 951-953 and the transmission start times of DL PPDUs 911-913, aspects of the present disclosure can ensure that AP3 does not miss the BA frame 953 transmitted from one or more of its associated STAs when decoding a BA frame 951 or 952 transmitted from an OBSS STA. For example, the offset may be selected based on one or both of the formats of the DL PPDUs 911-913 and the formats of the BA frames 951-953 to ensure that AP3 does not miss the BA frame 953 sent from one or more of its associated STAs when decoding the BA frame 951 or 952 sent from the OBSS STA associated with AP1 or AP2.

[0126] In some examples, the sending phase 920 is performed at time t 11 ends, and the TXOP obtained by AP1 is completed at time t 12 In other examples, the TXOP obtained by AP1 may extend beyond time t 12 , and the sending phase 920 may extend beyond time t 11 .

[0127] Figure 9C A timing diagram of another example wireless communication 900C supporting coordinated spatial reuse of DL transmissions according to some other implementations is shown. The wireless communication 900C is shown to include reference Figure 7A 、 Figure 7B and Figure 8 In some implementations, wireless communication 900C may be Figure 7B Another example of wireless communication 700B. In some aspects, Figure 9C The resource polling phase and the scheduling phase 910 are similar to those of reference Figure 7B The polling phase 705 and the scheduling phase 710 are described (for simplicity, Figure 9C The resource polling phase is not shown).

[0128] The transmission phase 920 begins at time t2, where AP1 transmits a DL PPDU 921 to one or more STAs associated with the first BSS. At time t3, which is offset by a certain period of time from time t2, AP2 transmits a DL PPDU 922 to one or more STAs associated with the second BSS. At time t4, which is offset by the same period of time from time t3, AP3 transmits a DL PPDU 923 to one or more STAs associated with the third BSS. Although for simplicity, Figure 9C The example shows that AP1, AP2, and AP3 transmit a single DL PPDU during the transmission phase 920, but in some other implementations, each of AP1, AP2, and AP3 may transmit multiple DL PPDUs to their associated STAs during the transmission phase 920.

[0129] exist Figure 9C In the example, the lengths or durations of DL PPDUs 921-923 may differ from one another, such that the transmission end times of the DL PPDUs 921-923 are offset by different time periods and do not appear in the same order as the transmission start times of the DL PPDUs 921-923. For example, when DL PPDU 921 transmitted from AP1 is the first DL transmission at time t2, DL PPDU 921 has the latest transmission end time at time t8. For another example, when DL PPDU 922 transmitted from AP2 is the second DL transmission at time t3, DL PPDU 922 has the earliest transmission end time at time t6. Therefore, the DL PPDUs 921-923 are misaligned with one another in a manner that not only prevents them from being transmitted using MU-MIMO, but also fails to prevent STAs from missing intra-BSS transmissions (such as DL PPDUs) when decoding the preamble of an OBSS packet.

[0130] Aspects of the present disclosure recognize that adjusting the duration of DL PPDUs 921-923 may not always be feasible. Thus, in some implementations, one or more of AP1, AP2, and AP3 may add different amounts of padding to the respective DL PPDUs 921, 922, and 923 such that the end times of transmission of the DL PPDUs 921-923 are offset from one another by a certain period of time. In some instances, the period of time may correspond to the amount of time associated with decoding the preamble of a wireless packet and determining, based on the decoded preamble, whether the wireless packet is an intra-BSS packet or an OBSS packet. Figure 9CIn the example of FIG, AP3 adds a certain amount of padding 983 to the DL PPDU 923 so that the transmission end time of the padded DL PPDU 923 is at time t9, and AP2 adds a certain amount of padding 982 to the DL PPDU 922 so that the transmission end time of the padded DL PPDU 922 is at time t 10 , and AP1 adds a certain amount of padding 981 to the DL PPDU 921 so that the transmission end time of the padded DL PPDU 921 is at time t 11 , for example, where time t 10 The period is offset from time t9, and time t 11 From time t 10 In this way, the time offset between the transmission end times of the corresponding DL PPDUs 921-923 may be the same as (or similar to) the time offset between the transmission start times of the corresponding DL PPDUs 921-923.

[0131] In some aspects, offsetting the end time of transmission of the DL PPDUs 921-923 by the time period causes the start times of transmission of acknowledgments of the DL PPDUs 921-923 to be offset from each other by the time period. For example, a STA associated with the third BSS may transmit a BA frame 963 to AP3 after a SIFS duration from the end of the DL PPDU 923, a STA associated with the second BSS may transmit a BA frame 962 to AP2 after a SIFS duration from the end of the DL PPDU 922, and a STA associated with the first BSS may transmit a BA frame 961 to AP1 after a SIFS duration from the end of the DL PPDU 921, wherein the transmission of the BA frame 962 is offset from the transmission of the BA frame 963 by the time period, and the transmission of the BA frame 961 is offset from the transmission of the BA frame 962 by the time period. BA frames 961-963 may be received by AP1-AP3, respectively, at times offset from each other by the time period.

[0132] In some instances, the TXOP obtained by AP1 at time t 12 In other examples, the TXOP obtained by AP1 may extend beyond time t 12 .

[0133] Figure 10 A timing diagram of an example wireless communication 1000 supporting coordinated spatial reuse of UL transmissions according to some other implementations is shown. The wireless communication 1000 is shown to include reference Figure 7A 、 Figure 7B and Figure 8 In some implementations, the wireless communication 1000 may be Figure 7AIn some aspects, Figure 10 The resource polling phase and scheduling phase 1010 of the example are similar to those of reference Figure 7A The polling phase 705 and the scheduling phase 710 are described (for simplicity, Figure 10 The resource polling phase is not shown in Figure 10 In the example of FIG, a coordinated access point transmission session may be designated for UL transmissions to AP1, AP2, and AP3.

[0134] The scheduling phase 1010 begins with AP1 transmitting an SR start frame to AP2 and AP3 over the wireless medium between times t0 and t1. The SR start frame may identify AP2 and AP3 (and other selected APs, if any) and may indicate scheduling information for UL transmissions to each of AP1, AP2, and AP3 during the coordinated access point transmission session. The SR start frame may also allocate wireless resources to the first, second, and third BSSs operated by AP1, AP2, and AP3, respectively. In some aspects, the SR start frame may indicate one or more portions of the TXOP shared by the first AP during the transmission phase 1030.

[0135] As discussed, the scheduling information may indicate the start time of UL transmissions to each of AP1, AP2, and AP3. The scheduling information may also indicate one or more of the MCS to be used for UL transmissions to each AP, the transmit power level to be used for UL transmissions to each AP, or the duration of UL transmissions to each AP. In some implementations, the SR Start frame may also include instructions for AP2 and AP3 to retransmit the scheduling information and resource allocations carried in the SR Start frame to their associated STAs in one or more scheduling frames. In some instances, the scheduling frame may be sent as multiple non-HT copy PPDUs over corresponding multiple subchannels of the wireless medium to one or more STAs associated with the respective APs. In this way, STAs with queued UL data may be able to detect and receive the scheduling frame regardless of the specific subchannel or subchannels on which the STA operates or resides.

[0136] AP2 and AP3 receive the SR Start frame and can decode the SR Start frame to obtain the scheduling information and resource allocation provided by AP1. In some instances, AP2 and AP3 can send a CTS frame over the wireless medium to acknowledge receipt of the SR Start frame. In other instances, AP2 and AP3 may not send a frame in response to the SR Start frame.

[0137] At time t2, AP1, AP2, and AP3 transmit a scheduling frame to their associated STAs over the wireless medium. The scheduling frame may include the same information carried in the SR Start frame (such as, but not limited to, scheduling information and resource allocation), for example, to ensure that all of the STAs associated with AP2 and AP3 obtain the scheduling information and resource allocation before the start of the transmission phase 1020. For example, although AP2 and AP3 may be within the wireless range of AP1 and able to receive and decode the SR Start frame, some of the STAs associated with AP2 or AP3 (or both) may not be within the wireless range of AP1 and, therefore, may not be able to receive or decode the SR Start frame transmitted by AP1. In this way, STAs associated with AP2 may obtain resource allocation and scheduling information from the scheduling frame transmitted by AP2, and STAs associated with AP3 may obtain resource allocation and scheduling information from the scheduling frame transmitted by AP3.

[0138] As discussed, in some implementations, the scheduling frame can be identical or similar to the SR start frame. In some implementations, the scheduling frames can be identical to each other and carry the same information as the SR start frame. For example, the scheduling frames can have the same format and the same transmission duration as each other, can be transmitted using the same MCS as each other, etc. In this way, the transmission of the scheduling frame from the corresponding AP can have minimal (if any) impact on the transmission of scheduling frames from other APs participating in the coordinated access point transmission session. As discussed, in some instances, the scheduling frame can be transmitted as multiple identical non-HT copy PPDUs over the wireless medium. The STAs associated with AP1, AP2, and AP3 receive the scheduling frame between time t3 and t4 and obtain the scheduling information and resource allocation indicated in the SR start frame.

[0139] The transmission phase 1020 begins at time t4, where AP1 receives an UL PPDU 1001 from one or more STAs associated with the first BSS. At time t5, which is offset by a certain period of time from time t4, AP2 begins receiving an UL PPDU 1002 from one or more STAs associated with the second BSS. At time t6, which is offset by the period of time from time t5, AP3 begins receiving an UL PPDU 1003 from one or more STAs associated with the third BSS. In some implementations, the transmission duration d1 of the UL PPDU 1001 can be configured or adjusted so that the transmission of the UL PPDU 1001 ends at time t8, the transmission duration d2 of the UL PPDU 1002 can be configured or adjusted so that the transmission of the UL PPDU 1002 ends at time t9 (which is offset by the period of time from time t8), and the transmission duration d3 of the UL PPDU 1003 can be configured or adjusted so that the transmission of the UL PPDU 1003 ends at time t9. 10(which is offset from time t9 by this time period) ends. Although for simplicity, Figure 10 The example shows that each of AP1, AP2, and AP3 receives a single UL PPDU during the transmission phase 1020, but in some other specific implementations, each of AP1, AP2, and AP3 may receive multiple UL PPDUs from their associated STAs during the transmission phase 1020.

[0140] In some implementations, AP1 may detect the transmission of UL PPDU 1001, decode the preamble of UL PPDU 1001 between time t4 and t5, and use the decoded preamble to determine that UL PPDU 1001 is an intra-BSS packet. Similarly, AP2 may detect the transmission of UL PPDU 1002, decode the preamble of UL PPDU 1002 between time t5 and t6, and use the decoded preamble to determine that UL PPDU 1002 is an intra-BSS packet. AP3 may detect the transmission of UL PPDU 1003, decode the preamble of UL PPDU 1003 between time t6 and t7, and use the decoded preamble to determine that UL PPDU 1003 is an intra-BSS packet. Figure 10 In the example shown in FIG, the transmission of UL PPDU 1001 to AP1 ends at time t8, the transmission of UL PPDU 1002 to AP2 ends at time t9, and the transmission of UL PPDU 1003 to AP3 ends at time t 10 Finish.

[0141] In some instances, shifting the transmission end times of the UL PPDUs 1001-1003 by the time period causes the transmission start times of the acknowledgements of the UL PPDUs 1001-1003 to be shifted by the time period. For example, AP1 transmits a BA frame 1011 over the wireless medium at time t9 (which may be a SIFS duration after time t8) to acknowledge successful reception of the UL PPDU 1001, and AP2 transmits a BA frame 1011 at time t9 (which may be a SIFS duration after time t8) to acknowledge successful reception of the UL PPDU 1001. 10 (which may be a SIFS duration after time t9) sends a BA frame 1012 over the wireless medium to acknowledge successful reception of the ULPPDU 1002, and AP3 receives the BA frame 1012 at time t9. 11 (It can be time t 10 1013 is transmitted over the wireless medium (after a SIFS duration) to confirm the successful reception of the UL PPDU 1003. In this way, the transmission of the BA frame 1012 is offset from the transmission of the BA frame 1011 by the time period, and the transmission of the BA frame 1013 is offset from the transmission of the BA frame 1012 by the time period. In some examples, the transmission phase 1020 is at time t 12ends, and the TXOP obtained by AP1 is completed at time t 13 In other examples, the TXOP obtained by AP1 may extend beyond time t 13 , and the sending phase 1020 may extend beyond time t 12 .

[0142] Although not shown for simplicity, in some other implementations, AP1 may send a trigger frame to AP2 and AP3 over the wireless medium between time t3 and t4. The trigger frame may identify AP2 and AP3 and may allocate wireless resources to the BSS operated by AP2 and AP3. The trigger frame may be any suitable trigger frame, including but not limited to a basic trigger frame or a MU-RTS trigger frame.

[0143] In some implementations, the offset between time t4 and t5 can be based on an amount of time associated with AP1 decoding a preamble of a wireless packet and determining, based on the decoded preamble, whether the wireless packet is an intra-BSS packet or an OBSS packet. For example, the offset between time t4 and t5 can allow AP1 to detect the transmission of the UL PPDU 1001, decode the preamble of the UL PPDU 1001, and use the decoded preamble to determine that the UL PPDU 1001 is an intra-BSS packet that may be intended for AP1.

[0144] For instances in which AP2 also detects the transmission of the UL PPDU 1001 and begins decoding the UL PPDU 1001, the offset between times t4 and t5 may allow AP2 time to decode the preamble of the UL PPDU 1001, determine that the UL PPDU 1001 is an OBSS packet based on the decoded preamble (such as the BSS color value carried in the preamble of the UL PPDU 1001), and discard the UL PPDU 1001 before AP2 receives the UL PPDU 1002. Then, between times t5 and t6, AP2 may detect the transmission of the UL PPDU 1002, decode the preamble of the UL PPDU 1002, and use the decoded preamble to determine that the UL PPDU 1002 is an intra-BSS packet that may be intended for AP2.

[0145] For the instance in which AP3 detects the transmission of the UL PPDU 1002 and begins decoding the UL PPDU 1002, the offset between times t5 and t6 may allow AP3 time to decode the preamble of the UL PPDU 1002, determine that the UL PPDU 1002 is an OBSS packet based on the decoded preamble (such as a BSS color value), and discard the UL PPDU 1002 before AP3 receives the UL PPDU 1003. Then, between times t6 and t7, AP3 may detect the transmission of the UL PPDU 1003, decode the preamble of the UL PPDU 1003, and use the decoded preamble to determine that the UL PPDU 1003 is an intra-BSS packet that may be intended for AP3.

[0146] In some implementations, the length or duration of one or more of the UL PPDUs 1001-1003 can be selectively adjusted or configured so that their respective durations d1, d2, and d3 are the same, ensuring that the transmission of the corresponding BA frames 1011-1013 is also offset from each other by this period. In this way, aspects of the present disclosure can ensure that the BA frames 1011-1013 are received and successfully decoded by AP1, AP2, and AP3, respectively.

[0147] Figure 11 A flow chart illustrating an example process 1100 for wireless communication supporting coordinated spatial reuse transmission according to some implementations is shown. Process 1100 may be performed by a wireless communication device such as a reference device. Figure 5 In some implementations, process 1100 can be performed by a first AP associated with a first BSS (such as a wireless communication device 500 described in the accompanying drawings). Figure 1 and Figure 6A For example, in some instances, process 1100 may be performed by one of the APs 102 and 602 described above. Figure 8 、 Figures 9A to 9C or Figure 10 The first AP described in one or more of the above is executed.

[0148] In some implementations, process 1100 begins at block 1102, where one or more other APs are selected for participating in a coordinated access point transmission session on a wireless medium with a first AP, wherein the one or more selected APs are associated with respective BSSs other than the first BSS. At block 1104, process 1100 continues with obtaining a transmit opportunity (TXOP) on the wireless medium. At block 1106, process 1100 continues with transmitting a frame indicating scheduling information for uplink (UL) or downlink (DL) transmissions to or from each of the selected APs during at least a portion of the TXOP obtained by the first AP, the scheduling information indicating respective start times of respective UL or DL transmissions to or from each of the selected APs during at least a portion of the TXOP obtained by the first AP, at least two of the start times being offset from each other by a time period associated with a preamble of a decoded wireless packet. In block 1108, the process 1100 continues by transmitting, at least partially concurrently with each of the selected APs transmitting, or receiving, one or more corresponding wireless packets to or from one or more corresponding STAs associated with the respective APs based on the scheduling information, one or more wireless packets to or from one or more corresponding STAs associated with the respective APs. In some aspects, the frame may indicate whether the coordinating access point transmit session is designated for UL transmissions or DL transmissions. In some other aspects, the frame may indicate an allocation of wireless resources for each of the selected APs during at least a portion of a TXOP obtained by the first AP.

[0149] In some implementations, the respective start times of UL or DL transmissions to or from the selected APs are based at least in part on one or both of the signal strength of wireless packets received by the first AP from the selected APs or the interference level associated with the selected APs. In some instances, the respective start times of UL or DL transmissions to or from at least some of the selected APs may be the same, for example, based at least in part on the respective signal strengths or interference levels associated with the at least some of the selected APs being relatively low (such as less than a certain value). Additionally or alternatively, the respective start times of UL or DL transmissions to or from at least some of the selected APs may be the same, for example, based at least in part on the respective decoding error rates of the first AP and at least some of the selected APs being relatively low (such as less than a certain threshold). In some other instances, the respective start times of UL or DL transmissions to or from at least two selected APs may be offset from each other by the time period, for example, based at least in part on the respective signal strengths or interference levels associated with the at least two selected APs being relatively high (such as greater than a certain value). Additionally or alternatively, respective start times of UL or DL transmissions to or from the at least two selected APs may be offset from one another by the time period, for example, based at least in part on respective decoding error rates of the first AP and the at least two selected APs being relatively high (e.g., greater than a certain threshold). In some aspects, the time period may be based at least in part on an amount of time associated with the respective APs decoding a preamble of a wireless packet and determining, based on the decoded preamble, whether the wireless packet is an intra-BSS packet or an OBSS packet.

[0150] In some other implementations, the scheduling information may indicate one or more of a respective modulation and coding scheme (MCS) to be used for UL or DL transmissions to or from each of the selected APs, a respective transmit power level to be used for UL or DL transmissions to or from each of the selected APs, or a respective duration of UL or DL transmissions to or from each of the selected APs. In some instances, the respective durations of UL or DL transmissions to or from the selected APs may be the same as one another. In some other instances, the respective durations of UL or DL transmissions to or from the selected APs may be different from one another.

[0151] In some instances, the frame may also indicate the respective durations of ACK frames or BA frames to be transmitted by one or more STAs associated with the respective AP. In some aspects, the respective durations of the ACK frames or BA frames may be the same as one another. In some other aspects, the respective durations of the ACK frames or BA frames may be different from one another.

[0152] In some other implementations, the frame may also include instructions for each of the selected APs to transmit scheduling information and resource allocations in a scheduling frame to one or more STAs associated with the corresponding AP. In some aspects, the scheduling frame may be transmitted as multiple high-throughput (HT) copies to the one or more STAs associated with the corresponding AP over a corresponding plurality of subchannels of the wireless medium. In this way, STAs associated with DL transmissions from the selected AP may be able to detect and receive the scheduling frame regardless of the specific subchannel that the corresponding STA is monitoring.

[0153] Figure 12 A flow chart illustrating an example process 1200 for wireless communication supporting coordinated spatial reuse transmission according to some implementations is shown. The process 1200 may be performed by a wireless communication device such as a reference device. Figure 5 In some implementations, process 1200 can be performed by a first AP associated with a first BSS (such as a wireless communication device 500 described in the accompanying drawings). Figure 1 and Figure 6A For example, in some instances, process 1200 may be performed by one of the APs 102 and 602 described above. Figure 8 、 Figures 9A to 9C or Figure 10 The first AP described in one or more of is executed.

[0154] In some examples, process 1200 may be Figure 11 The process 1200 may be implemented as a specific embodiment of the process 1200 in block 1102. For example, at block 1202, the process 1200 may begin by sending a polling frame to a plurality of APs associated with a BSS different from the first BSS. At block 1204, the process 1200 may continue by receiving, in response to the polling frame, a request from one or more of the plurality of APs for the first AP to share a portion of the obtained TXOP with the respective APs. At block 1206, the process 1200 may continue by selecting, based on the received requests, one or more APs to participate in the coordinated access point transmission session.

[0155] Figure 13 A flow chart illustrating an example process 1300 for wireless communication supporting coordinated spatial reuse transmission according to some implementations is shown. Process 1300 may be performed by a wireless communication device (such as the one described above with reference to FIG. Figure 5 In some implementations, the process 1300 may be performed by a first AP (such as the wireless communication device 500 described above). Figure 1 and Figure 6A For example, in some instances, process 1300 may be performed by one of the APs 102 and 602 described above. Figure 8 、 Figures 9A to 9Cor Figure 10 The first AP described in one or more of is executed.

[0156] In some examples, process 1300 can be combined with Figure 11 The process 1300 may be performed in conjunction with sending or receiving one or more wireless packets in block 1108 of the process 1300. For example, at block 1302, the process 1300 may begin by selectively adjusting a length or duration of each of one or more wireless packets sent to or received from one or more STAs associated with a first AP based at least in part on one or more of a respective signal strength of the wireless packets received from the selected AP, a respective interference level associated with the selected AP, or a respective decoding error rate of the first AP and the selected AP.

[0157] Figure 14A An example SR start frame 1400 according to some implementations is shown. The SR start frame 1400 is shown to include a PHY preamble 1401, a MAC header 1402, a common information field 1403, a plurality of per-BSS information fields 1404(1)-1404(n), and a frame check sequence (FCS) field 1405. The PHY preamble 1401 may include a legacy preamble portion and a non-legacy preamble portion (not shown for simplicity). The legacy preamble portion (which may be Figure 3B An example of a legacy preamble portion 322 of FIG. 1 includes L-STF, L-LTF, and L-SIG fields. In some instances, the non-legacy preamble portion may be Figure 3B The MAC header 1402 may include a frame control field, a duration field, a receiver address (RA) field, and a transmitter address (TA) field. The frame control field may include a type and subtype field 1410, which may be set to new or unused values to indicate the SR start frame 1400.

[0158] The common information field 1403 may store information common to the APs participating in the coordinated access point transmission session. In some implementations, the common information field 1403 may include a data duration subfield 1421, a response duration subfield 1422, a bandwidth subfield 1423, and a UL / DL indication subfield 1424. The data duration subfield 1421 may indicate the respective time durations of UL or DL transmissions to or from the participating AP. The response duration subfield 1422 may indicate the respective time durations of ACK frames or BA frames to be sent by STAs associated with the participating AP. The bandwidth subfield 1423 may indicate the channel width available to the participating AP for UL or DL transmissions during the coordinated access point transmission session. The UL / DL indication subfield 1424 may indicate whether the coordinated access point transmission session is designated for UL transmissions to or from the participating AP.

[0159] Each of the per-BSS information fields 1404(1)-1404(n) may store scheduling information for the BSS of the corresponding participating AP. In some instances, each of the per-BSS information fields 1404(1)-1404(n) may include one or more of an AP ID subfield 1431, a STA ID subfield 1432, a Tx power limit subfield 1433, a maximum interference subfield 1434, and a scheduling information subfield 1435. The AP ID subfield 1431 carries information identifying the corresponding participating AP. The STA ID subfield 1432 carries information identifying the STA associated with the corresponding participating AP. The Tx power limit subfield 1433 may indicate a transmit power level limit that will not be exceeded during a coordinated access point transmission session. The maximum interference subfield 1434 may indicate a maximum interference level that can be tolerated at the corresponding participating AP during a coordinated access point transmission session. The scheduling information subfield 1435 may indicate a transmission schedule for UL or DL transmissions to or from the corresponding participating AP. In some instances, the scheduling information subfield 1435 may also indicate one or more of a corresponding MCS to be used for UL or DL transmissions to or from each selected AP in the selected APs, a corresponding start time to be used for UL or DL transmissions to or from each selected AP in the selected APs, or a corresponding duration of UL or DL transmissions to or from each selected AP in the selected APs.

[0160] In other implementations, the SR Start frame 1400 may be based on a new variant of the base trigger frame specified by 802.11ax, 802.11be, and subsequent amendments to the IEEE 802.11 family of wireless communication standards. In some aspects, as disclosed herein, a new or unused value carried in the subtype field of the MAC header of the base trigger frame may indicate that the frame is an SR Start frame. In some other implementations, the SR Start frame 1400 may be based on the MU-RTS trigger frame specified by 802.11ax, 802.11be, and subsequent amendments to the IEEE 802.11 family of wireless communication standards. In some aspects, one or more reserved bits in the PHY header or MAC header of the MU-RTS trigger frame may be used to indicate that the frame is an SR Start frame.

[0161] Figure 14B An example SR start frame 1450 according to some other implementations is shown. The SR start frame 1450 is similar to Figure 14A 1450, except that the common information field 1453 of the SR start frame 1450 includes a scheduling information subfield 1455 (instead of each of the per-BSS information fields 1454(1)-1454(n) of the SR start frame 1450). Specifically, the scheduling information subfield 1455 of the SR start frame 1450 carries scheduling information that is common to all of the APs participating in the coordinated access point transmission session. In some examples, the scheduling information subfield 1455 can be a single bit that indicates whether the start times of UL or DL transmissions to or from the participating APs are offset from each other by a certain period of time. In other examples, the scheduling information subfield 1455 can carry a common transmission start time, a common MCS, a common transmission time offset, a common UL or DL transmission duration, or any combination thereof.

[0162] Figure 15 A block diagram of an example wireless communication device 1500 is shown. In some implementations, the wireless communication device 1500 can be configured to perform respective references to Figure 11 、 Figure 12 and Figure 13 One or more of the processes 1100, 1200, or 1300 described. The wireless communication device 1500 may be Figure 1 Any STA among STA 104, Figure 5 Wireless communication device 500 or Figure 6B More specifically, the wireless communication device 1500 may be a chip, SoC, chipset, package, or device that includes at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0163] The wireless communication device 1500 includes a receiving component 1510, a communication manager 1520, and a transmitting component 1530. The communication manager 1520 also includes an AP selection component 1522, a TXOP sharing component 1524, and / or a UL / DL alignment component 1526. Portions of one or more of the components 1522, 1524, or 1526 may be implemented at least in part in hardware or firmware. In some implementations, one or more of the components 1522, 1524, or 1526 are implemented at least in part as a memory device stored in a memory such as a computer. Figure 5 For example, portions of one or more of components 1522, 1524, or 1526 may be implemented as software that can be executed by a processor such as Figure 5 Non-transitory instructions (or “code”) executed by the processor 506 of the device to perform the functions or operations of the corresponding component.

[0164] The receiving component 1510 is configured to receive RX signals from one or more other wireless communication devices, and the transmitting component 1530 is configured to transmit TX signals to one or more other wireless communication devices. The communication manager 1520 is configured to manage wireless communications with one or more other wireless communication devices. In some implementations, the AP selection component 1522 may identify or select one or more other APs for participating in a coordinated access point transmission session on the wireless medium. The TXOP sharing component 1524 may allocate one or more portions of the TXOP on the wireless medium obtained by the wireless communication device 1500 to the one or more other APs selected for participating in the coordinated access point transmission session. The UL / DL alignment component 1526 may selectively adjust the timing or duration (or both) of UL transmissions to one or more selected APs or DL transmissions from one or more selected APs based on one or more of signal strength, interference level, or decoding error rates of the first AP and the selected APs.

[0165] Specific implementation examples are described in the following numbered clauses:

[0166] 1. A method for wireless communication by a first access point (AP) associated with a first basic service set (BSS), comprising:

[0167] selecting one or more other APs for participating in a coordinated access point transmission session on a wireless medium with the first AP, the one or more selected APs being associated with respective BSSs other than the first BSS;

[0168] Obtaining a transmit opportunity (TXOP) on the wireless medium;

[0169] transmitting a frame indicating scheduling information for uplink (UL) or downlink (DL) transmissions to or from each of the selected APs during at least a portion of the TXOP obtained by the first AP, the scheduling information indicating respective start times of the respective UL or DL transmissions to or from the selected APs during at least the portion of the TXOP obtained by the first AP, at least two of the start times being offset from each other by a time period associated with a preamble of a decoded wireless packet; and

[0170] Based on the scheduling information, each of the selected APs sends one or more corresponding wireless packets to one or more corresponding stations (STAs) associated with the corresponding AP or receives one or more corresponding wireless packets from the one or more corresponding stations (STAs) associated with the corresponding AP, and at least partially concurrently sends one or more wireless packets to one or more STAs associated with the first AP or receives one or more wireless packets from the one or more STAs associated with the first AP.

[0171] 2. The method of clause 1, wherein the frame indicates whether the coordinated access point transmission session is designated for UL transmissions to the selected AP or DL transmissions from the selected AP.

[0172] 3. A method according to any one or more of clauses 1 to 2, wherein the respective start times of the UL or DL transmissions to or from the selected AP are based at least in part on one or both of the signal strength of wireless packets received by the first AP from the selected AP or the interference level associated with the selected AP.

[0173] 4. A method according to clause 3, wherein the respective start times of the UL or DL transmissions to or from at least some of the selected APs are the same as each other based at least in part on respective signal strengths or interference levels associated with the at least some of the selected APs being less than a certain value.

[0174] 5. A method according to any one or more of clauses 1 to 3, wherein the respective start times of the UL or DL transmissions to or from the at least two selected APs are offset from each other by the time period based at least in part on the respective signal strengths or interference levels associated with the at least two selected APs being greater than a certain value.

[0175] 6. A method according to any one or more of clauses 1 to 5, wherein the scheduling information indicates one or more of a corresponding modulation and coding scheme (MCS) to be used for the UL or DL transmission to or from each selected AP in the selected APs, a corresponding transmission power level to be used for the UL or DL transmission to or from each selected AP in the selected APs, or a corresponding duration of the UL or DL transmission to or from each selected AP in the selected APs.

[0176] 7. The method of clause 6, wherein the respective durations of the UL or DL transmissions to or from the selected AP are identical to one another.

[0177] 8. A method according to clause 6, wherein the respective durations of the UL or DL transmissions to or from at least some of the selected APs differ from each other by a second time period associated with the decoding of a preamble of an acknowledgment (ACK) frame or a block acknowledgment (BA) frame received by a respective AP among the at least some of the selected APs.

[0178] 9. A method according to any one or more of clauses 1 to 8, wherein the frame further indicates a corresponding duration of an acknowledgment (ACK) frame or a block acknowledgment (BA) frame to be transmitted by the one or more corresponding STAs associated with each of the selected APs.

[0179] 10. The method of clause 9, wherein the respective durations of the ACK frame or the BA frame are identical to one another.

[0180] 11. A method according to any one or more of clauses 1 to 10, wherein the frame further indicates an allocation of time or frequency resources for the corresponding UL or DL transmission to or from each of the selected APs during at least the portion of the TXOP obtained by the first AP.

[0181] 12. The method according to any one or more of clauses 1 to 11, wherein the selecting comprises:

[0182] sending a polling frame to a plurality of APs associated with a BSS different from the first BSS;

[0183] receiving, in response to the polling frame, from each of one or more of the plurality of APs, a request for the first AP to share a portion of the obtained TXOP with the corresponding AP; and

[0184] The one or more APs are selected for participating in the coordinated access point transmission session based on the received request.

[0185] 13. The method according to any one or more of clauses 1 to 12, further comprising:

[0186] The length or duration of each of the one or more wireless packets sent to or received from the one or more STAs associated with the first AP is selectively adjusted based at least in part on the signal strength of the wireless packets received by the first AP from the selected AP, the interference level associated with the selected AP, or one or more of the decoding error rates of the first AP and the selected AP.

[0187] 14. A method as described in any one or more of clauses 1 to 13, wherein the frame includes instructions for each of the selected APs to send the scheduling information to the one or more respective STAs associated with the respective selected AP.

[0188] 15. The method of clause 14, wherein the scheduling information is sent as a respective plurality of non-high throughput (HT) copies to the one or more STAs associated with the first AP over a corresponding plurality of subchannels of the wireless medium.

[0189] 16. A first access point (AP) associated with a first basic service set (BSS), comprising:

[0190] at least one processor; and

[0191] at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor, is configured to:

[0192] selecting one or more other APs for participating in a coordinated access point transmission session on a wireless medium with the first AP, the one or more selected APs being associated with respective BSSs other than the first BSS;

[0193] transmitting a frame indicating scheduling information for uplink (UL) or downlink (DL) transmissions to or from each of the selected APs during at least a portion of the TXOP obtained by the first AP, the scheduling information indicating respective start times of the respective UL or DL transmissions to or from the selected APs during at least the portion of the TXOP obtained by the first AP, at least two of the start times being offset from each other by a time period associated with a preamble of a decoded wireless packet; and

[0194] Based on the scheduling information, each of the selected APs sends one or more corresponding wireless packets to one or more corresponding stations (STAs) associated with the corresponding AP or receives one or more corresponding wireless packets from the one or more corresponding stations (STAs) associated with the corresponding AP, and at least partially concurrently sends one or more wireless packets to one or more STAs associated with the first AP or receives one or more wireless packets from the one or more STAs associated with the first AP.

[0195] 17. The first AP of clause 16, wherein the frame indicates whether the coordinated access point transmission session is designated for UL transmissions to the selected AP or DL transmissions from the selected AP.

[0196] 18. A first AP as described in any one or more of clauses 16 to 17, wherein the respective start times of the UL or DL transmissions to or from the selected AP are based at least in part on one or both of the signal strength of wireless packets received by the first AP from the selected AP or the interference level associated with the selected AP.

[0197] 19. A first AP according to clause 18, wherein the respective start times of the UL or DL transmissions to or from at least some of the selected APs are the same as each other based at least in part on respective signal strengths or interference levels associated with the at least some of the selected APs being less than a certain value.

[0198] 20. The first AP of clause 18, wherein the respective start times of the UL or DL transmissions to or from the at least two selected APs are offset from each other by the time period based at least in part on a determined signal strength or interference level associated with the at least two selected APs being greater than a certain value.

[0199] 21. A first AP according to any one or more of clauses 16 to 20, wherein the scheduling information indicates one or more of a corresponding modulation and coding scheme (MCS) to be used for the UL or DL transmission to or from each selected AP in the selected APs, a corresponding transmission power level to be used for the UL or DL transmission to or from each selected AP in the selected APs, or a corresponding duration of the UL or DL transmission to or from each selected AP in the selected APs.

[0200] 22. The first AP of clause 21, wherein the respective durations of the UL or DL transmissions to or from the selected AP are identical to one another.

[0201] 23. A first AP according to clause 21, wherein the respective durations of the UL or DL transmissions to or from at least some of the selected APs differ from each other by a second time period associated with a respective AP among the at least some of the selected APs decoding a preamble of an acknowledgment (ACK) frame or a block acknowledgment (BA) frame received by the respective AP.

[0202] 24. The first AP of any one or more of clauses 16 to 23, wherein the frame further indicates an acknowledgement (ACK) frame or a block acknowledgement (BA) frame to be transmitted by the one or more respective STAs associated with each of the selected APs.

[0203] The corresponding duration of the frame.

[0204] 25. The first AP of clause 24, wherein the respective durations of the ACK frame or the BA frame are identical to one another.

[0205] 26. A first AP according to any one or more of clauses 16 to 25, wherein the frame further indicates an allocation of time or frequency resources for the corresponding UL or DL transmission to or from each of the selected APs during at least the portion of the TXOP obtained by the first AP.

[0206] 27. The first AP of any one or more of clauses 16 to 26, wherein execution of the processor readable code for selecting the one or more APs is configured to:

[0207] sending a polling frame to a plurality of APs associated with a BSS different from the first BSS;

[0208] receiving, in response to the polling frame, a request from one or more of the plurality of APs for the first AP to share a portion of the obtained TXOP with the corresponding AP; and

[0209] The one or more APs are selected for participating in the coordinated access point transmission session based on the received request.

[0210] 28. The first AP of any one or more of clauses 16 to 27, wherein execution of the processor readable code is further configured to:

[0211] The length or duration of each of the one or more wireless packets sent to or received from the one or more STAs associated with the first AP is selectively adjusted based at least in part on one or more of the corresponding signal strength of the wireless packets received by the first AP from the selected AP, the corresponding interference level associated with the selected AP, or the corresponding decoding error rates of the first AP and the selected AP.

[0212] 29. The first AP of any one or more of clauses 16 to 28, wherein the frame includes a first AP for each of the selected APs to send a first AP to the corresponding selected AP.

[0213] The one or more associated corresponding STAs send an instruction of the scheduling information.

[0214] 30. The first AP of clause 29, wherein the scheduling information is sent as a respective plurality of non-high throughput (HT) copies to the one or more STAs associated with the first AP over a corresponding plurality of subchannels of the wireless medium.

[0215] As used herein, a phrase referring to "at least one of" or "one or more of" a list of items refers to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to cover the following possibilities: only a, only b, only c, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b, and c. As used herein, "based on" is intended to be interpreted in an inclusive sense unless otherwise expressly indicated. For example, "based on" can be used interchangeably with "based at least in part on" unless otherwise expressly indicated. Specifically, unless the phrase in the context means "based only on 'one'" or the equivalent, whether it is "based on 'one'" or "based at least in part on 'one'" can be based on "one" alone or on a combination of "one" and one or more other factors, conditions, or information.

[0216] The various illustrative components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in conjunction with the specific implementations disclosed herein may be implemented as electronic hardware, firmware, software, or a combination of hardware, firmware, or software, including the structures disclosed in this specification and their structural equivalents. This interchangeability of hardware, firmware, and software has been generally described in terms of their functionality and exemplified in the various illustrative components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the specific application and the design constraints imposed on the overall system.

[0217] Various modifications to the specific implementations described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other specific implementations without departing from the spirit or scope of this disclosure. Therefore, the claims are not intended to be limited to the specific implementations shown herein but are to be accorded the widest scope consistent with this disclosure, the principles, and the novel features disclosed herein.

[0218] Additionally, various features described in this specification in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented in multiple implementations separately or in any suitable subcombination. Thus, although features may be described above as functioning in a particular combination and even initially claimed as such, one or more features from a claimed combination may in some cases be deleted from the combination, and a claimed combination may be directed to a subcombination or variations of the subcombination.

[0219] Similarly, although operations are depicted in a specific order in the figures, this should not be understood as requiring such operations to be performed in the specific order shown or in a sequential order, or to perform all illustrated operations to achieve the desired result. In addition, the accompanying drawings may schematically depict one or more example processes in the form of a flow chart or a flow diagram. However, other operations not depicted may be incorporated into the example processes schematically illustrated. For example, one or more additional operations may be performed before, after, simultaneously, or between any of the illustrated operations. In some cases, multitasking and parallel processing may be advantageous. In addition, the separation of the various system components in the specific implementation described above should not be understood as requiring such separation in all specific implementations, but rather should be understood as described program components and systems that can be integrated together in a single software product, or be packaged into multiple software products.

Claims

1. A method for wireless communication by a first access point (AP), comprising: selecting one or more other APs for participating in a coordinated access point transmission session on a wireless medium with the first AP, the selected one or more APs being associated with respective other basic service sets (OBSSs) different from a first basic service set (BSS) associated with the first AP; transmitting a frame indicating scheduling information for uplink (UL) or downlink (DL) transmissions to or from each selected AP of the selected APs during at least a portion of a transmit opportunity (TXOP) obtained by the first AP, the scheduling information indicating respective start times of respective UL or DL transmissions to or from each selected AP of the selected APs during the portion of the TXOP, at least two of the start times being offset from each other by a time period associated with decoding a preamble of a wireless packet and associated with determining whether the wireless packet is an intra-BSS packet or an OBSS packet; as well as Based on the scheduling information, each of the selected APs sends one or more corresponding wireless packets to one or more corresponding stations (STAs) associated with the corresponding AP or receives one or more corresponding wireless packets from the one or more corresponding stations (STAs) associated with the corresponding AP, and at least partially concurrently sends one or more wireless packets to one or more STAs associated with the first AP or receives one or more wireless packets from the one or more STAs associated with the first AP.

2. The method of claim 1, wherein the frame indicates whether the coordinated access point transmission session is designated for UL transmissions to the selected AP or DL transmissions from the selected AP.

3. The method of claim 1 , wherein the respective start times of the UL or DL transmissions to or from the selected AP are based at least in part on one or both of a signal strength of wireless packets received by the first AP from the selected AP or an interference level associated with the selected AP.

4. The method of claim 3 , wherein the respective start times of the UL or DL transmissions to or from at least some of the selected APs are the same as one another based at least in part on respective signal strengths or interference levels associated with the at least some of the selected APs being less than a certain value.

5. The method of claim 3 , wherein the respective start times of the UL or DL transmissions to or from the at least two selected APs are offset from each other by the time period based at least in part on respective signal strengths or interference levels associated with the at least two selected APs being greater than a certain value.

6. A method according to claim 1, wherein the scheduling information indicates one or more of a corresponding modulation and coding scheme (MCS) to be used for the UL or DL transmission to or from each selected AP in the selected APs, a corresponding transmission power level to be used for the UL or DL transmission to or from each selected AP in the selected APs, or a corresponding duration of the UL or DL transmission to or from each selected AP in the selected APs.

7. The method of claim 6, wherein the respective durations of the UL or DL transmissions to or from the selected AP are identical to one another.

8. A method according to claim 6, wherein the respective durations of the UL or DL transmissions to or from at least some of the selected APs differ from each other by a second time period associated with the decoding of a preamble of an acknowledgment (ACK) frame or a block acknowledgment (BA) frame received by a respective AP among the at least some of the selected APs.

9. The method of claim 1, wherein the frame further indicates respective durations of acknowledgement (ACK) frames or block acknowledgement (BA) frames to be transmitted by the one or more respective STAs associated with each of the selected APs.

10. The method of claim 9, wherein the respective durations of the ACK frame or the BA frame are identical to each other.

11. The method of claim 1 , wherein the frame further indicates an allocation of time or frequency resources for the respective UL or DL transmissions to or from each of the selected APs during at least the portion of the TXOP obtained by the first AP.

12. The method of claim 1, wherein the selecting comprises: sending a polling frame to a plurality of APs associated with a BSS different from the first BSS; receiving, in response to the polling frame, from each of one or more of the plurality of APs, a request for the first AP to share a portion of the obtained TXOP with the corresponding AP; as well as The one or more APs are selected for participating in the coordinated access point transmission session based on the received request.

13. The method according to claim 1, further comprising: The length or duration of each of the one or more wireless packets sent to or received from the one or more STAs associated with the first AP is selectively adjusted based at least in part on one or more of the corresponding signal strength of the wireless packets received by the first AP from the selected AP, the corresponding interference level associated with the selected AP, or the corresponding decoding error rate of the first AP and the selected AP.

14. The method of claim 1, wherein the frame includes instructions for each of the selected APs to transmit the scheduling information to the one or more respective STAs associated with the respective selected AP.

15. The method of claim 14, wherein the scheduling information is transmitted as a respective plurality of non-high throughput (HT) copies to the one or more STAs associated with the first AP over a corresponding plurality of sub-channels of the wireless medium.

16. A first access point (AP), comprising: at least one processor; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor, is configured to: selecting one or more other APs for participating in a coordinated access point transmission session on a wireless medium with the first AP, the selected one or more APs being associated with respective other basic service sets (OBSSs) different from a first basic service set (BSS) associated with the first AP; transmitting a frame indicating scheduling information for uplink (UL) or downlink (DL) transmissions to or from each selected AP of the selected APs during at least a portion of a transmit opportunity (TXOP) obtained by the first AP, the scheduling information indicating respective start times of respective UL or DL transmissions to or from each selected AP of the selected APs during the portion of the TXOP, at least two of the start times being offset from each other by a time period associated with decoding a preamble of a wireless packet and associated with determining whether the wireless packet is an intra-BSS packet or an OBSS packet; as well as Based on the scheduling information, each of the selected APs sends one or more corresponding wireless packets to one or more corresponding stations (STAs) associated with the corresponding AP or receives one or more corresponding wireless packets from the one or more corresponding stations (STAs) associated with the corresponding AP, and at least partially concurrently sends one or more wireless packets to one or more STAs associated with the first AP or receives one or more wireless packets from the one or more STAs associated with the first AP.

17. The first AP of claim 16, wherein the frame indicates whether the coordinated access point transmission session is designated for UL transmissions to the selected AP or DL transmissions from the selected AP.

18. A first AP according to claim 16, wherein the respective start times of the UL or DL transmissions to or from the selected AP are based at least in part on one or both of the signal strength of wireless packets received by the first AP from the selected AP or the interference level associated with the selected AP.

19. A first AP according to claim 18, wherein the respective start times of the UL or DL transmissions to or from at least some of the selected APs are the same as each other based at least in part on respective signal strengths or interference levels associated with the at least some of the selected APs being less than a certain value.

20. The first AP of claim 18, wherein the respective start times of the UL or DL transmissions to or from the at least two selected APs are offset from each other by the time period based at least in part on a determined signal strength or interference level associated with the at least two selected APs being greater than a certain value.

21. A first AP according to claim 16, wherein the scheduling information indicates one or more of a corresponding modulation and coding scheme (MCS) to be used for the UL or DL transmission to or from each selected AP in the selected APs, a corresponding transmission power level to be used for the UL or DL transmission to or from each selected AP in the selected APs, or a corresponding duration of the UL or DL transmission to or from each selected AP in the selected APs.

22. The first AP of claim 21, wherein the respective durations of the UL or DL transmissions to or from the selected AP are identical to one another.

23. A first AP according to claim 21, wherein the respective durations of the UL or DL transmissions to or from at least some of the selected APs differ from each other by a second time period associated with the decoding of a preamble of an acknowledgment (ACK) frame or a block acknowledgment (BA) frame received by a respective AP among the at least some of the selected APs.

24. The first AP of claim 16, wherein the frame further indicates respective durations of acknowledgement (ACK) frames or block acknowledgement (BA) frames to be transmitted by the one or more respective STAs associated with each of the selected APs.

25. The first AP of claim 24, wherein the respective durations of the ACK frame or the BA frame are identical to each other.

26. The first AP of claim 16, wherein the frame further indicates an allocation of time or frequency resources for the respective UL or DL transmissions to or from each of the selected APs during at least the portion of the TXOP obtained by the first AP.

27. The first AP of claim 16, wherein execution of the processor readable code for selecting the one or more APs is configured to: sending a polling frame to a plurality of APs associated with a BSS different from the first BSS; receiving, in response to the polling frame, a request from one or more of the plurality of APs for the first AP to share a portion of the obtained TXOP with the respective AP; as well as The one or more APs are selected for participating in the coordinated access point transmission session based on the received request.

28. The first AP of claim 16, wherein execution of the processor readable code is further configured to: The length or duration of each of the one or more wireless packets sent to or received from the one or more STAs associated with the first AP is selectively adjusted based at least in part on one or more of the corresponding signal strength of the wireless packets received by the first AP from the selected AP, the corresponding interference level associated with the selected AP, or the corresponding decoding error rate of the first AP and the selected AP.

29. The first AP of claim 16, wherein the frame includes instructions for each of the selected APs to transmit the scheduling information to the one or more respective STAs associated with the respective selected AP.

30. The first AP of claim 29, wherein the scheduling information is transmitted as a respective plurality of non-high throughput (HT) copies to the one or more STAs associated with the first AP over a corresponding plurality of sub-channels of the wireless medium.

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