Power control for coordinated transmissions from overlapping wireless local area networks

Abstract

This disclosure provides systems, devices, apparatuses, and methods, including computer programs encoded on a storage medium, for blocking or reducing cross-network interference associated with coordinated transmissions on a wireless channel. A first access point (AP) of a first basic service set (BSS) and a second AP of a second BSS may concurrently use wireless channels during a portion of a transmission opportunity (TXOP) using coordinated transmissions. A TXOP owner, such as a first AP, may allocate a resource assignment to a second AP such that the resource assignment is conditionally available to the second AP for coordinated transmissions. The condition may prevent the second BSS from using the resource assignment if the use of the resource assignment by the second BSS may interfere with the first BSS. The condition may be based on a transmit power of a downlink communication or an uplink communication in the second BSS.

Description

[0001] This application is a divisional application of an application with an application date of October 1, 2019, application number 201980063091.4 (international application number PCT / US2019 / 054018), and name “Power Control for Coordinated Transmissions from Overlapping Wireless Local Area Networks”.

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This patent application claims priority to U.S. Provisional Patent Application No. 16 / 589,041 filed on September 30, 2019, and U.S. Provisional Patent Application No. 62 / 739,768 filed on October 1, 2018, both of which are entitled "POWER CONTROL FOR COORDINATED TRANSMISSIONS FROM OVERLAPPING WIRELESSLOCAL AREA NETWORKS" and are assigned to the assignee of this application. The disclosures of these prior applications are considered part of this patent application and are incorporated into this patent application by reference. Technical Field

[0004] The present disclosure relates generally to the field of wireless communications, and more particularly to coordinated transmissions from overlapping wireless local area networks. Background Art

[0005] A wireless local area network (WLAN) may be formed by one or more access points (APs) that provide a shared wireless communication medium for use by several client devices (also referred to as stations (STAs)). The basic building block of a WLAN that complies with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards is a basic service set (BSS) managed by an AP. Each BSS is identified by a basic service set identifier (BSSID) announced by the AP. The AP periodically broadcasts beacon frames so that any STA within the wireless range of the AP can establish or maintain a communication link with the WLAN. The STA may have a wireless connection (referred to as a wireless association, or simply "association") if it has been authenticated and has established a wireless session with the AP. One or more STAs in the WLAN may communicate with the AP using the shared wireless communication medium. The AP may have the opportunity to influence the distribution of available resources in the shared wireless communication medium.

[0006] As more WLANs are deployed in an environment, the wireless medium may be shared by multiple APs and their corresponding BSSs. For example, a first BSS (managed by a first AP) may utilize a first wireless channel. A second BSS (managed by a second AP) may also utilize the first wireless channel for separate communications independent of the first BSS. The second BSS may be referred to as an overlapping BSS (OBSS) relative to the first BSS. It may be desirable to coordinate communications performed by multiple BSSs in an environment to improve spectrum efficiency and quality of service for WLAN devices in the corresponding BSSs. Summary of the invention

[0007] 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.

[0008] One innovative aspect of the subject matter described in the present disclosure may be implemented in a method for wireless communication. In some implementations, the method may be performed by a first access point (AP) of a first basic service set (BSS). The method may also be performed by a wireless device (such as a station) that provides at least a portion of the functionality of an AP in the first BSS. The method may include: transmitting a multi-AP scheduling trigger (MAP-Sch-Trigger) message to multiple APs during a first portion of a transmission opportunity, the multiple APs including one or more second APs of one or more corresponding second BSSs. The method may include: receiving one or more scheduling indications from the one or more second APs in response to the MAP-Sch-Trigger message. The method may include: allocating resources to the one or more second APs based on the scheduling indication for coordinated transmission on a wireless channel during a second portion of the transmission opportunity, the resources allocated to each of the one or more second APs being subject to a condition based on a corresponding transmit power of a corresponding second AP or a corresponding second station (STA) of the corresponding second BSS and being available to the second AP or the second STA. The method may include transmitting a multi-AP coordinated transmission trigger (MAP-CT-Trigger) message to the multiple APs to indicate the start of the second portion of the allocated resources and the transmission opportunity. The method may include transmitting data to or receiving data from at least a first STA of the first BSS as part of the coordinated transmission during the second portion of the transmission opportunity.

[0009] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a method for wireless communication. In some implementations, the method may be performed by a first access point (AP) of a wireless local area network (WLAN). The method may also be performed by a wireless device (such as a station) in the WLAN that provides at least a portion of the functionality of an AP. The method may include: communicating a multi-AP scheduling trigger (MAP-Sch-Trigger) message during a first portion of a transmission opportunity of a wireless channel. The first AP may be a controller of the transmission opportunity. The method may include: providing a resource assignment to a second AP for coordinated transmission on the wireless channel during a second portion of the transmission opportunity. The resource assignment may be conditionally available to the second WLAN based at least in part on a condition that the use of the resource assignment by the second WLAN will cause interference to the first WLAN. The method may include: communicating a multi-AP coordinated transmission trigger (MAP-CT-Trigger) message to indicate the start of the second portion of the transmission opportunity. The method may include: communicating between the first AP and at least a first station (STA) associated with the first AP via coordinated transmission during the second portion of the transmission opportunity.

[0010] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a wireless communication device. In some implementations, the wireless communication device may be used in a first AP of a first BSS. The wireless communication device may include at least one modem, at least one processor communicatively coupled to the at least one modem. The wireless communication device may include at least one memory communicatively coupled to the at least one processor and storing processor-readable code, which, when executed by the at least one processor in conjunction with the at least one modem, causes the wireless communication device to implement any method of the present disclosure.

[0011] Another innovative aspect of the subject matter described in this disclosure can be implemented in a tangible computer-readable storage medium including non-transitory processor-executable code that, when executed by at least one processor of a wireless device, can cause the wireless device to implement any of the methods in this disclosure.

[0012] In some implementations, methods, wireless communication devices, and computer-readable storage media may be configured to determine that the first AP is a controller of the transmission opportunity based on determining that the first AP has won contention for the transmission opportunity.

[0013] In some implementations, the first AP may be a master AP or other AP with a dedicated role as the controller of transmission opportunities including this transmission opportunity.

[0014] In some implementations, the coordinated transmission includes concurrent uplink communication from the first STA to the first AP and from one or more second STAs to the respective second APs. The condition may be configured to prevent the second STA from using the respective allocated resources when the transmit power of the respective second STA is above a threshold.

[0015] In some implementations, various methods, wireless communication devices, and computer-readable storage media may be configured to include a coordinated uplink (CO-UL) parameter in a MAP-Sch-Trigger message or a MAP-CT-Trigger message, the CO-UL parameter indicating the condition.

[0016] In some implementations, the CO-UL parameters are based on the transmit power of the first AP and the amount of interference that the first AP will tolerate.

[0017] In some implementations, the MAP-Sch-Trigger message is configured to cause one or more second APs to retransmit the CO-UL parameter to one or more second STAs in the corresponding second STAs. The CO-UL parameter can be used by each second STA to determine whether the transmit power of the second STA will cause interference to the first AP above a threshold.

[0018] In some implementations, the coordinated transmission may include concurrent downlink communications from the first AP to the first STA and from one or more second APs to respective second STAs. The condition may be configured to prevent the second AP from using the respective allocated resources when the transmit power of the respective second AP is above a threshold.

[0019] In some implementations, methods, wireless communication devices, and computer-readable storage media may be configured to: indicate to the first STA during the first part of the transmission opportunity to transmit a test communication for measuring a first received signal strength indicator (RSSI) between the first STA and the first AP. In some implementations, methods, wireless communication devices, and computer-readable storage media may be configured to: determine a coordinated downlink (CO-DL) parameter based at least in part on an estimated transmit power used by the first AP for coordinated transmission and an estimated channel quality between the first AP and the first STA. The estimated channel quality may be estimated based on the first RSSI. In some implementations, methods, wireless communication devices, and computer-readable storage media may be configured to: include the CO-DL parameter in a MAP-Sch-Trigger message or a MAP-CT-Trigger message to a second AP.

[0020] In some implementations, the test communication may be a null packet or a quality of service (QoS) packet.

[0021] In some implementations, the methods, wireless communication devices, and computer-readable storage media may be configured to cause one or more second APs to measure a corresponding second RSSI of a test communication from a first STA. The CO-DL parameter and the corresponding second RSSI may be used by the second AP to determine whether a corresponding transmit power of the second AP will cause interference to the first STA above a threshold.

[0022] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a method for wireless communication. In some implementations, the method may be performed by a second AP. Another innovative aspect of the subject matter described in the present disclosure may be implemented in a second AP. The second AP may include at least one processor and at least one memory communicatively coupled to the at least one processor. The memory may store processor-readable code, which, when executed by the at least one processor, may cause the second AP to perform operations as described in the method. Another innovative aspect of the subject matter described in the present disclosure may be implemented in a tangible computer-readable storage medium including non-transient processor executable code, which, when executed by at least one processor of a STA, may cause the STA to perform the operations of the described method.

[0023] In some implementations, the methods and operations may include: receiving a multi-AP scheduling trigger (MAP-Sch-Trigger) message from a first AP of a first BSS during a first portion of a transmission opportunity. In some implementations, the first AP may be a controller of the transmission opportunity. In some implementations, the methods and operations may include: transmitting one or more scheduling indications from a second AP to the first AP in response to the MAP-Sch-Trigger message. In some implementations, the methods and operations may include: receiving a multi-AP coordinated transmission trigger (MAP-CT-Trigger) message from a first AP, wherein the MAP-CT-Trigger message indicates the start of the second portion of the allocated resources and the transmission opportunity. The allocated resources may be allocated by the first AP based on the scheduling indication for coordinated transmission on a wireless channel during the second portion of the transmission opportunity. The resources allocated to the second AP may be subject to conditions based on the corresponding transmit power of the second AP or the second station (STA) of the second BSS and available to the second AP or the second STA. In some implementations, methods and operations may include transmitting or receiving data to or from a second STA concurrently with communications between the first AP and the first STA as part of a coordinated transmission using the allocated resources during the second portion of the transmission opportunity.

[0024] In some implementations, the coordinated transmission includes concurrent uplink communications from the first STA to the first AP and from the second STA to the second AP.The condition may be configured to prevent the second STA from using the allocated resources when the transmit power of the second STA is above a threshold.

[0025] In some implementations, the methods and operations may include receiving a coordinated uplink (CO-UL) parameter in a MAP-Sch-Trigger message or a MAP-CT-Trigger message, the CO-UL parameter indicating the condition. For example, the CO-UL parameter may be based on a transmit power of the first AP and an amount of interference that the first AP will tolerate.

[0026] In some implementations, the methods and operations may include retransmitting the CO-UL parameters to the second STAs in the scheduling message. The CO-UL parameters may be used by each second STA to determine whether the transmit power of the second STA will cause an amount of interference above a threshold to the first AP.

[0027] In some implementations, coordinated transmissions may be configured for concurrent downlink communications from a first AP to a first STA and from a second AP to a second STA. The condition may be configured to prevent the second AP from using resource assignments when the transmit power of the second AP would cause interference to the first STA above a threshold.

[0028] In some implementations, methods and operations may include receiving coordinated downlink (CO-DL) parameters from the first AP in a MAP-Sch-Trigger message or a MAP-CT-Trigger message during a first portion of a transmission opportunity. The CO-DL parameters may indicate the condition.

[0029] In some implementations, the methods and operations may include measuring a first received signal strength indicator (RSSI) between the first STA and the second AP based on a test communication transmitted by the first STA. In some implementations, the methods and operations may include determining a downlink power limit based at least in part on the CO-DL parameters and the first RSSI. In some implementations, the methods and operations may include determining whether to use resource assignments for concurrent downlink communications based at least in part on the downlink power limit and a power setting of the second AP.

[0030] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a method for wireless communication. In some implementations, the method may be performed by a second STA of a second BSS. Another innovative aspect of the subject matter described in the present disclosure may be implemented in a second STA. The second STA may include at least one processor and at least one memory communicatively coupled to the at least one processor. The memory may store processor-readable code, which, when executed by the at least one processor, may cause the second STA to perform operations as described in the method. Another innovative aspect of the subject matter described in the present disclosure may be implemented in a tangible computer-readable storage medium including non-transient processor-executable code, which, when executed by at least one processor of the second STA, may cause the second STA to perform operations. In some implementations, each method and operation may include: during a first portion of a transmission opportunity and receiving a message from a second AP, the message including the allocated resources of the transmission opportunity for coordinated transmission during a second portion of the transmission opportunity controlled by a first AP of the first BSS. In some implementations, the methods and operations may include determining at least one condition for preventing use of the allocated resources based on whether a transmit power of the second STA would cause interference above a threshold amount to communications between the first AP and the first STA associated with the first AP. In some implementations, the methods and operations may include transmitting data from the second STA to the second AP concurrently with communications between the first STA and the first AP as part of the coordinated transmission during the second portion of the transmission opportunity based on determining that the at least one condition is satisfied.

[0031] In some implementations, the condition may be based on an amount of interference that the first AP will tolerate due to the second STA's use of the allocated resources.

[0032] In some implementations, the methods and operations may include receiving a coordinated uplink (CO-UL) parameter and an identifier of a first AP. In some implementations, the methods and operations may include detecting a multi-AP coordinated transmission trigger (MAP-CT-Trigger) message transmitted from the first AP using the identifier of the first AP, the MAP-CT-Trigger message indicating the start of a second portion of the transmission opportunity. In some implementations, the methods and operations may include determining whether to use the allocated resources based at least in part on the CO-UL parameter.

[0033] In some implementations, the methods and operations may include measuring the signal strength of the MAP-CT-Trigger message. In some implementations, the methods and operations may include determining an uplink power limit for coordinated transmissions from the second STA to the second AP based on the signal strength and the CO-UL parameter. In some implementations, the methods and operations may include determining whether the condition is met based at least in part on the uplink limit and the transmit power setting of the second STA. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Details of one or more implementations of the subject matter described in the present disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from this description, the accompanying drawings, and the claims. It should be noted that the relative dimensions of the following drawings may not be drawn to scale.

[0035] Figure 1A A schematic diagram of an example wireless communication network is shown.

[0036] Figure 1B A schematic diagram showing multiple wireless local area networks (WLANs) that may use coordinated transmissions is shown.

[0037] Figure 2 A conceptual diagram of Orthogonal Frequency Division Multiplexing (OFDM) and Orthogonal Frequency Division Multiple Access (OFDMA) is shown to illustrate resource assignment for wireless channels.

[0038] Figure 3 An example of a multi-access point (multi-AP) coordination technique that supports coordinated transmission during a transmission opportunity (TXOP) is illustrated.

[0039] Figure 4 An example of a multiple access point scheduling technique in the first part of a TXOP is illustrated.

[0040] Figure 5 An example of concurrent scheduling for multiple access points (APs) in the first part of a TXOP is illustrated.

[0041] Figure 6 An example of uplink coordinated transmission in which interference may be a consideration is illustrated.

[0042] Figure 7 An example of downlink coordinated transmission in which interference may be a consideration is illustrated.

[0043] Figure 8 An example of a protocol sequence for uplink OFDMA to support uplink coordinated transmission is illustrated.

[0044] Fig. 9An example of a protocol sequence for downlink OFDMA to support downlink coordinated transmission is illustrated.

[0045] Fig. 10A An example of a multi-AP physical protocol data unit is illustrated.

[0046] Fig. 10B Another example of a multi-AP physical protocol data unit is illustrated.

[0047] Fig.11 A conceptual diagram illustrating an example message format for communicating one or more parameters for coordinated transmissions.

[0048] Fig.12 A block diagram of an example wireless communication device is shown.

[0049] Fig.13A A block diagram of an example access point (AP) is shown.

[0050] Fig. 13B A block diagram of an example station (STA) is shown.

[0051] Fig.14 A flow chart illustrating an example process for coordinated transmission performed by a first AP according to some implementations is shown.

[0052] Fig.15 A flow chart illustrating another example process for coordinated transmission performed by a first AP according to some implementations is shown.

[0053] Fig.16 A flow chart illustrating an example process for coordinated transmission performed by a second AP according to some implementations is shown.

[0054] Fig.17 A flow chart illustrating another example process for coordinated transmission performed by a second AP according to some implementations is shown.

[0055] Fig.18 A flow diagram is shown illustrating an example process for coordinated transmissions performed by STAs associated with neighboring APs according to some implementations.

[0056] Fig.19 A block diagram of an example AP is shown in accordance with some implementations.

[0057] Fig. 20 A block diagram of an example STA according to some implementations is shown.

[0058] Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION

[0059] The following description is directed to certain implementations in order to describe 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 many different ways. The described implementations can be implemented in a manner that can be implemented in accordance with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, the Bluetooth Special Interest Group (SIG), or the like. The described implementations may be implemented in any device, system, or network capable of transmitting and receiving radio frequency (RF) signals according to one or more of the LTE, 3G, 4G, or 5G standards, etc. The described implementations may be implemented in any device, system, or network capable of transmitting 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 frequency division multiple access (OFDMA), 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 personal area network (WPAN), a wireless local area network (WLAN), a wireless wide area network (WWAN), or an Internet of Things (IoT) network.

[0060] A wireless local area network (WLAN, sometimes called Wi-Fi) in a home, apartment, business, or other area. TM A network) may include one or more WLAN devices. Each WLAN device may have a station (STA) interface, which is an addressable entity that shares a wireless communication medium with other STAs. An access point (AP) is a WLAN device that includes a STA interface and a distribution system access function. For the sake of brevity in this disclosure, a WLAN device may be referred to as an AP or a STA to distinguish the functional role of a WLAN device in a WLAN. The basic building block of a WLAN is a basic service set (BSS), which is managed by an AP and includes one or more STAs associated with the AP. For the sake of brevity in this disclosure, a first WLAN includes a first AP and a first STA associated with the first AP, and a second WLAN includes a second AP and a second STA associated with the second AP. The first WLAN may be referred to as a first BSS, and the second WLAN may be referred to as a second BSS (or overlapping BSS, OBSS).

[0061] Various implementations of the present disclosure generally relate to coordinated transmissions performed by different WLANs during a transmission opportunity (TXOP) of a wireless channel. In some aspects of the present disclosure, a scheme for multi-AP scheduling is provided, in which a first AP can obtain channel access and become a TXOP owner (which can also be referred to as a leader AP of the TXOP). In the present disclosure, for simplicity, each example consistently uses the first AP as the TXOP owner and the second AP as a neighboring AP. In other examples (such as different TXOPs), the second AP can be the TXOP owner. As a TXOP owner, the first AP can communicate with the second AP (such as a neighboring AP, which is not the TXOP owner of the TXOP) to allow both the first AP and the second AP to access the wireless channel concurrently during the TXOP using coordinated transmission. During the coordinated transmission, the first WLAN and the second WLAN can communicate concurrently using different resources of the wireless channel. The use of coordinated transmission can improve the spectral efficiency of the wireless channel. However, the potential risk of coordinated transmission is that the second WLAN may cause cross-network interference to the first WLAN. In the case where the second WLAN's participation in coordinated transmission will interfere with the first WLAN, it may be desirable to limit or prevent the second WLAN from participating in coordinated transmission.

[0062] According to the present disclosure, a first AP (as a TXOP owner) may allocate a resource assignment that is conditionally available to a second AP for coordinated transmission on a wireless channel during a portion of the TXOP. The first AP may communicate at least one condition for preventing the use of the resource assignment if the use of the resource assignment would cause interference to the first AP. The first AP may send a parameter to the second AP that the second AP (or a STA associated with the second AP) may use to determine whether to participate in coordinated transmission. For example, the parameter may be related to the power level, channel quality, interference tolerance, or a combination thereof regarding the first WLAN. The first AP may calculate the parameter and provide it to the second AP. The second AP may use the parameter and information about the second WLAN (such as power level or estimated signal path loss) to determine whether the use of the resource assignment will cause too much interference to the first WLAN.

[0063] In some aspects of the present disclosure, coordinated transmission may involve uplink communication (from STA to AP) performed by both a first WLAN and a second WLAN. For example, a first STA may communicate with a first AP while a second STA communicates with a second AP at the same time. However, if the first AP receives an uplink transmission of the second STA with a signal strength above a threshold, the transmission of the second STA may interfere with the uplink transmission of the first STA. The first AP may not be able to successfully decode the uplink transmission of the first STA. This may occur, for example, when the second STA is closer to the first AP than the first STA. According to the present disclosure, the second STA (or any other STA of the OBSS) may refrain from participating in the coordinated transmission if participating in the coordinated transmission will interfere with the uplink communication of the first WLAN. Since the first AP (and thus the first BSS) is the TXOP owner of the TXOP, the goal may be to ensure that the first WLAN can use the TXOP even if the first WLAN has provided resource assignments to the second WLAN.

[0064] In some implementations, a first AP may send a coordinated uplink (CO-UL) parameter to a second AP. The CO-UL parameter may be included in a multi-AP scheduling trigger (MAP-Sch-Trigger) message for providing resource assignments to neighboring APs. A neighboring AP (such as a second AP) may retransmit the CO-UL parameter to its corresponding STA (such as a second STA). The OBSS STA may use the CO-UL parameter to determine whether to utilize coordinated transmission. In some implementations, the CO-UL parameter is related to the amount of interference that the first AP will tolerate due to the use of resource assignments by the OBSS STA. The OBSS AP (such as a second AP) may also indicate an identifier of the first AP (such as a color code or a BSSID) so that the OBSS STA can detect transmissions from the first AP. The OBSS STA may measure the signal strength of the transmission from the first AP. The OBSS STA may also estimate the amount of transmit power used to enable the OBSS STA to communicate OBSS uplink communications to the OBSS AP as part of a coordinated transmission. In some implementations, the OBSS STA may participate in coordinated transmissions after determining that the estimated transmit power of the OBSS uplink communication is below a limit. The limit may be determined using the signal strength of the transmission from the first AP and the CO-UL parameters.

[0065] In some aspects of the present disclosure, coordinated transmissions may involve downlink communications (from AP to STA) performed by both a first WLAN and a second WLAN. For example, a first AP may communicate with a first STA while a second AP communicates with a second STA at the same time. However, if the first STA receives a downlink transmission of the second AP with a signal strength above a threshold, the transmission of the second AP may interfere with the downlink transmission of the first AP. The first STA may not be able to successfully decode the downlink transmission of the first AP. This may occur, for example, when the first STA is closer to the second AP than the first AP. According to the present disclosure, the second AP may refrain from participating in the coordinated transmission if participating in the coordinated transmission interferes with the downlink communication of the first WLAN. Since the first AP (and thus the first BSS) is the TXOP owner of the TXOP, the goal may be to ensure that the first WLAN can use the TXOP even if the first WLAN has provided resource assignments to the second WLAN.

[0066] In some implementations, the first AP may send a coordinated downlink (CO-DL) parameter to the second AP. The CO-DL parameter may be included in a MAP-Sch-Trigger message used to provide resource assignments to neighboring APs. A neighboring AP (such as a second AP) may use the CO-DL parameter to determine whether to utilize coordinated transmission. In some implementations, the first AP may also cause its intended downlink STA (such as a first STA) to transmit a test communication, which the first AP and the neighboring AP may use to determine signal strength or path loss. The neighboring AP may measure the signal strength of the test communication from the first STA. The neighboring AP may also estimate the amount of transmit power used to enable the neighboring AP to communicate OBSS downlink communications to the OBSS STA as part of the coordinated transmission. The neighboring AP may participate in the coordinated transmission after determining that the estimated transmit power of the OBSS downlink communication is below a limit. The limit may be determined using the signal strength of the test communication from the first STA and the CO-DL parameter.

[0067] Specific implementations of the subject matter described in the present disclosure may be implemented to achieve one or more of the following potential advantages. A first AP of a first WLAN (as a TXOP owner) may share a frequency portion of a TXOP (as a resource assignment) with a second AP of a second WLAN (a neighboring AP) for coordinated transmissions during a portion of the TXOP. The second AP may use the resource assignment when the second AP's use of the resource assignment will not interfere with the first AP's use of the TXOP. Thus, the TXOP owner is not penalized for sharing a portion of the TXOP, while the use of coordinated transmissions may improve the spectral efficiency of the wireless channel. In addition, in some implementations, the use of coordinated transmissions may be implemented without direct management or backhaul coordination by different WLANs sharing the wireless channel. The use of a CO-UL parameter or a CO-DL parameter may represent a concise metric that provides sufficient information for a second AP or STA in a second WLAN to determine whether to participate in coordinated transmissions.

[0068] Figure 1A 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 802.11 family of wireless communication protocol 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 network 100 may also include a plurality of APs 102.

[0069] 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.

[0070] A single AP 102 and an associated set of STAs 104 may be referred to as a basic service set (BSS), which is managed by the corresponding AP 102 . Figure 1A Additionally shown is an example coverage area 106 of the AP 102, which may represent a basic service area (BSA) of the WLAN 100. The 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 a media access control (MAC) address of the AP 102. The AP 102 periodically broadcasts a beacon frame ("beacon") including the BSSID to enable any STA 104 within the wireless range of the AP 102 to "associate" or re-associate 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 corresponding 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 respective STAs 104 in the WLAN via the corresponding communication links 108.

[0071] 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 GHz, 6 GHz, or 60 GHz bands). To perform a passive scan, the STA 104 listens for beacons transmitted by the corresponding AP 102 at periodic time intervals, referred to as target beacon transmission times (TBTTs), measured in time units (TUs), where one TU may be equal to 1024 microseconds (μs). To perform an active scan, the STA 104 generates a probe request and sequentially transmits the probe request 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 to associate with 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. At the end of the association operation, the AP 102 assigns an association identifier (AID) to the STA 104, which the AP 102 uses to track the STA 104.

[0072] As wireless networks become more and more popular, STA 104 may have the opportunity to select one of many BSSs within the range of the STA, or to select among multiple APs 102 that together form an extended service set (ESS) including multiple connected BSSs. The extended network station associated with 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, STA 104 can be covered by more than one AP 102 and can be associated with different APs 102 at different times for different transmissions. Additionally, after associating with AP 102, STA 104 may also be configured to periodically scan its surroundings to find a more suitable AP 102 to associate with. 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 desirable network characteristics (such as a larger received signal strength indicator (RSSI) or a reduced traffic load).

[0073] In some cases, STA 104 may form a network without AP 102 or other equipment other than STA 104 itself. 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, although STA 104 may be able to communicate with each other through AP 102 using a communication link 108, STA 104 may also communicate directly with each other via a direct wireless link 110. Additionally, two STAs 104 may communicate via a direct communication link 110, regardless of whether the two STAs 104 are associated with the same AP 102 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 a STA 104 may be referred to as a group master (GO) and may coordinate transmissions within the ad hoc network. Examples of direct wireless 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.

[0074] The AP 102 and the STA 104 may function and communicate (via corresponding communication links 108) in accordance with the IEEE 802.11 family of wireless communication protocol standards, such as those defined by the IEEE 802.11-2016 specification or its revisions, 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 media access control (MAC) layers. The AP 102 and the STA 104 transmit and receive wireless communications (hereinafter also referred to as "Wi-Fi communications") to 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 may transmit PPDUs on an unlicensed spectrum, which may be a portion of a spectrum that includes frequency bands traditionally used by Wi-Fi technology, such as the 2.4 GHz band, the 5 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 may also communicate in other frequency bands, such as the 6 GHz band, that may support both licensed and unlicensed communications. The AP 102 and STA 104 may also be configured to communicate on other frequency bands, such as shared licensed frequency bands, where multiple operators may have licenses to operate in the same or overlapping frequency band or bands.

[0075] Each frequency band may include multiple sub-bands or frequency channels. For example, PPDUs that comply with IEEE 802.11n, 802.11ac, and 802.11ax standard revisions may be transmitted on 2.4 and 5 GHz frequency bands, where each frequency band is divided into multiple 20 MHz channels. In this way, these PPDUs are transmitted on a physical channel with a minimum bandwidth of 20 MHz, but larger channels may be formed through channel bonding. For example, a PPDU may be transmitted on a physical channel with a bandwidth of 40 MHz, 80 MHz, 160 MHz, or 320 MHz by bonding multiple 20 MHz channels together.

[0076] 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 PDSU. In an instance where the PPDU is transmitted over a bonded channel, the preamble field can be replicated and transmitted in each of a plurality of 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 may be used for packet detection, automatic gain control, and channel estimation, among other purposes. The legacy preamble may also generally be used to maintain compatibility with legacy devices. The format, encoding, and information provided therein of the legacy portion of the preamble are based on the specific IEEE 802.11 protocol to be used to transmit the payload.

[0077] Figure 1B A schematic diagram showing multiple WLANs that may use coordinated transmissions is shown. Figure 1B A system diagram 101 includes an environment with more than one WLAN operating overlapping coverage areas. A first WLAN may be managed by a first AP 110 establishing a first BSS. Similarly, a second WLAN may be managed by a second AP 120 establishing a second BSS, and a third WLAN may be managed by a third AP 130 establishing a third BSS. Each of the APs 110, 120, and 130 may be similar to Figure 1A 102 described in . Each WLAN may be a network that implements at least one of the IEEE 802.11 family of standards, such as the standards defined by the IEEE 802.11-2016 specification or its revisions. Each WLAN may provide access to other networks (not shown). For example, AP 110 may be connected to a gateway device (not shown) that provides connectivity to another network (not shown). Each WLAN may include numerous wireless communication devices, such as an AP and a plurality of STAs. Figure 1B In the example of FIG. 1 , the first AP 110 may have multiple STAs 104 and 114 that are wirelessly associated with the first AP 110. Although the first AP 110 is described as an access point using an infrastructure mode, in some implementations, the first AP 110 may be a STA that operates as an AP. For example, the first AP 110 may be a STA that can operate in a peer-to-peer mode or an independent mode. In other examples, the first AP 110 may be a software AP (SoftAP) that operates on a computer system.

[0078] A single AP and its associated STAs may be referred to as a basic service set (BSS), which is managed by the corresponding AP. Figure 1BIn the example of , the first BSS includes the first AP 110 and the first STA 114. The second BSS includes the second AP 120 and the second STA 124. The third BSS includes the third AP 130 and the third STA 134. It should be noted that Figure 1B The locations of the STAs 104, 114, 124, 134 in FIG. 1 are arbitrarily illustrated as examples. The STAs 104, 114, 124, 134 may have different locations relative to their associated APs. The STAs 104, 114, 124, 134 may be mobile and change location over time. Figure 1B As shown in , an associated STA may be closer to a different AP than the AP to which the STA is associated. For example, a first STA 114 may be closer to a second AP 120, even though the first STA 114 is wirelessly associated with the first AP 110. "Non-associated STAs" may not be considered part of the BSS because they do not have a wireless session established at the AP. The BSS is identified by a service set identifier (SSID) advertised by the AP. Each STA in the WLAN can communicate with an external network and each other via the AP 110 and the corresponding communication link 106.

[0079] Figure 1B Additionally illustrated are example coverage areas associated with each AP. For example, a first coverage area 118 of AP 110 is illustrated, which may represent a basic service area (BSA) of a first WLAN. An example second coverage area 128 of a second AP 120 may form a BSA of a second WLAN, and an example third coverage area 138 of a third AP 130 may form a BSA of a third WLAN. As wireless networks become more popular, a STA may have the opportunity to select one of many BSSs within range of the STA, or to select among multiple APs that together form an extended service set (ESS) including multiple connected BSSs.

[0080] exist Figure 1B In the example of , APs 110, 120, and 130 may be configured to use the same wireless channel. For example, the first BSS, the second BSS, and the third BSS may be referred to as overlapping BSSs (OBSSs) because they are configured for the same wireless channel in the same location. Typically, APs may share wireless channels using time-based partitioning of wireless channels or obtaining access through contention-based procedures. For example, channel access may use orthogonal frequency division multiplexing (OFDM). In newer WLAN communication technologies, orthogonal frequency division multiple access (OFDMA) may provide more efficient use of wireless channels. OFDMA is used in Figure 2 OFDMA refers to the ability to subdivide a wireless channel into resource units that can be assigned to different WLAN devices.

[0081] In a contention-based procedure, WLAN devices (such as APs 110, 120, and 130) can determine whether a wireless channel is available and can win contention for an upcoming transmission opportunity (TXOP). Following conventional contention-based procedures, a TXOP will be reserved exclusively for the WLAN device that wins contention for channel access. For example, the first AP 110 can win contention for the next TXOP. The first AP 110 can be referred to as a TXOP owner. In newer technologies, APs can be configured to support coordinated transmissions on wireless channels. Coordinated transmission refers to a technology in which multiple WLAN devices can transmit concurrently using subbands (or resource assignments) during a portion of a TXOP. A TXOP owner (such as the first AP 110) can allocate a resource assignment to another AP (such as the second AP 120). The resource assignment can be a subchannel or frequency-divided resource unit (similar to OFDMA) from a wireless channel during the time of coordinated transmission.

[0082] During coordinated transmission, the first WLAN and the second WLAN may communicate concurrently using different resource assignments of the wireless channel. The use of coordinated transmission may improve the spectrum efficiency of the wireless channel. However, a potential risk of coordinated transmission is that the second WLAN may cause cross-network interference to the first WLAN. For example, as described above, the first STA 114 may be closer to the second AP 120 than the first AP 110 to which it is associated. If both the first AP 110 and the second AP 120 transmit downlink signals during coordinated transmission, the downlink signal from the second AP 120 may cause interference that prevents the first STA 114 from correctly receiving the downlink signal from the first AP 110. Similarly, for uplink signals, the first STA 114 and the second STA 124 may transmit uplink signals concurrently to the first AP 110 and the second AP 120, respectively. The second STA 124 may be closer to the first AP 110 , and the coordinated transmission may unintentionally cause interference to the first AP 110 , which prevents the first AP 110 from properly receiving uplink signals from the first STA 114 .

[0083] In an example of the present disclosure, a first WLAN (including a first AP 110 and a first STA 114) may be a TXOP owner. Although the use of coordinated transmission may permit the first WLAN to share a wireless channel with another WLAN, it may be desirable to limit or prevent the second WLAN from participating in the coordinated transmission if the second WLAN's participation in the coordinated transmission would interfere with the first WLAN. Therefore, in some implementations, the first WLAN may conditionally provide a resource assignment so that the second WLAN uses the resource assignment only if the second WLAN can use the resource assignment without interfering with the first WLAN. For concurrent downlink coordinated transmissions, the first AP 110 may communicate at least one parameter (referred to as a CO-DL parameter in the present disclosure) to the second AP, which the second AP 120 may use to determine whether the resource assignment may be used without interfering with the second STA 124. For concurrent uplink coordinated transmissions, the first AP 110 may communicate at least one parameter (referred to as a CO-UL parameter in the present disclosure) to the second AP 120, which the second AP 120 may send to the second STA 124. The second STA 124 may use the CO-UL parameters to determine whether the resource assignment may be used without interfering with the first AP 110 .

[0084] Figure 2 A conceptual diagram of OFDM and OFDMA is shown to illustrate resource assignment for a wireless channel. Figure 2 The top of the figure shows a conceptual diagram of OFDM 201. The OFDM channel width may include multiple subcarriers. WLAN packet 230 (also referred to as PPDU) includes data encoded using subcarriers of the channel width. For example, a first STA may transmit a first PPDU 210 during a first time period. During a second time period, a second STA may transmit a second PPDU 220. PPDUs 210 and 220 may be of different time lengths. Typically, the first STA and the second STA (as well as any other STA in the BSS) will contend for access to the channel. Once a STA wins the contention, the STA may use the channel to transmit a PPDU. As shown in FIG. Figure 2 As shown in , the different shading of the PPDU indicates that different STAs can utilize the wireless channels in sequence, one at a time. However, this communication structure may be inefficient if the STA does not have enough data to justify the use of the full channel width. IEEE 802.11ax introduces the use of OFDMA in WLAN.

[0085] Figure 2The bottom of the figure shows a conceptual diagram of OFDMA 202. OFDMA decomposes the channel width into multiple resource units (RUs). Each RU may include a different number of subcarriers. Using OFDMA, the AP can allocate different RUs to different STAs. For example, PPDU 250 may include different RUs allocated for a first STA, a second STA, a third STA, and a fourth STA. One RU240 is allocated for a STA to transmit uplink data in PPDU 250, while other RUs are allocated for different STAs. The allocation of RUs can be used to schedule channel access. For example, a trigger message from an AP may indicate which RUs are allocated to a specific STA for uplink traffic in a PPDU following the trigger message.

[0086] According to the present disclosure, the concept of scheduling resource assignments can be used in conjunction with coordinated transmissions. For example, a TXOP owner (such as a first AP) can provide a resource assignment to a neighboring AP (such as a second AP). The neighboring AP can use the resource assignment to schedule RUs for OBSS STAs, or can use the resource assignment for downlink transmissions. By using coordinated transmissions, both the first AP and the second AP can be able to transmit or receive wireless communications during the TXOP.

[0087] Figure 3 An example of a multi-AP coordination technique 300 that supports coordinated transmission during a TXOP 303 is illustrated. In this example, a first AP 110, a second AP 120, and a third AP 130 may perform coordinated transmission 325. This example is based on a contention-based communication system. In some newer frequency bands (such as 6G), wireless channels may be scheduled by a delegated or selected semi-permanent TXOP owner. Initially, in a contention-based procedure, APs 110, 120, and 130 may contend for access to a wireless channel during a contention / countdown window 305. In this example, the first AP 110 may first contend for channel access (such as according to a contention-based EDCA channel access procedure) and may win control of the TXOP. The first AP 110 may be referred to as a TXOP owner. In other systems, there may be other ways for the first AP 110 to become the TXOP owner of the upcoming TXOP. Regardless of how the first AP 110 becomes the TXOP owner of the wireless channel, the first AP 110 may control scheduling resources during the TXOP.

[0088] Upon winning the contention-based channel access procedure, the first AP 110 may initiate a multi-AP scheduling phase during the first portion 307 of the TXOP. Figure 3In an example of , the first AP 110 may transmit a multi-AP scheduling trigger (which may be referred to as a MAP-Sch-Trigger 310 message). The MAP-Sch-Trigger 310 may be received by each of the second AP 120 and the third AP 130. The MAP-Sch-Trigger 310 may be a MAP PPDU that the first AP 110 transmits to initiate scheduling of multi-AP communications. The second AP 120 and the third AP 130 may transmit one or more multi-AP scheduling 315 communications, which may be received by one or more associated STAs and also received by the first AP 110. Based on the transmissions of the second AP 120 and the third AP 130, the first AP 110 may determine the wireless resources (such as frequency resources, time resources, or a combination thereof) that will be used for multi-AP communications in the second portion 317 of the TXOP. The first AP 110 may then transmit a multi-AP coordinated transmission trigger message (which may be referred to as a MAP-CT-Trigger 320 message) to indicate the start of the second portion 317 of the TXOP. The MAP-CT-Trigger 320 may indicate to each of the other APs 120 and 130 that a coordinated transmission may follow. In some cases, the coordinated transmission 325 may include transmissions from all participating BSSs simultaneously within the second portion 317 of the TXOP. As indicated above, the resources within the coordinated transmission 325 may be allocated based on time resources, frequency resources, or using coordinated OFDMA utilizing orthogonal channels.

[0089] Figure 4An example of a multi-access point scheduling technique 400 in the first part of a TXOP is illustrated. As with all examples in this disclosure, a first AP 110 may be the TXOP owner of an upcoming TXOP. The first AP 110 may transmit a MAP-Sch-Trigger to each neighboring AP 120 and 130 (one neighboring AP at a time) to initiate scheduling for multi-AP communications. The first AP 110 may send a first MAP-Sch-Trigger 410, which may be received by a second AP 120. In this case, the second AP 120 may transmit a scheduling indication 415 to its associated STAs, which may also be received by the first AP 110. The first AP 110 may then send a second MAP-Sch-Trigger 420, which may be received by a third AP 130. In this case, the third AP 130 may transmit a scheduling indication 425 to its associated STAs, which may also be received by the first AP 110. Based on the scheduling indications 415 and 425, the first AP 110 may determine resources for transmissions of each of the APs 110, 120, and 130, and may transmit a MAP-Trigger 430 to initiate the coordinated transmission 325.

[0090] In this example, the MAP-Sch-trigger 410 or 420 targets only one neighboring AP at any time, and the scheduling indications 415 and 425 will not interfere with each other. In some cases, the scheduling indications 415 and 425 may include scheduling indication (SI) frame transmissions sent by each neighboring AP 120 and 130 to its associated STAs. As the TXOP owner, the first AP 110 monitors the SI frames and can determine when to poll the next AP. Such techniques provide relatively simple scheduling for multi-AP communications, but consume time resources associated with multiple APs.

[0091] Figure 5 An example of concurrent scheduling 500 for multiple APs in a first portion of a TXOP is illustrated. In this example, a first AP 110, a second AP 120, and a third AP 130 may perform coordinated transmissions in which concurrent scheduling of multiple APs 110, 120, and 130 may be achieved. As previously described, the first AP 110 may be the TXOP owner of an upcoming TXOP. The first AP 110 may transmit a MAP-Sch-Trigger 310 to initiate scheduling of multi-AP communications. In this case, the second AP 120 and the third AP 130 may concurrently transmit scheduling indications.

[0092] In some cases, the scheduling indication may be provided in a MAP-PPDU from each of the second AP 120 and the third AP 130. The subchannel used by each AP 120 and 130 to transmit the SI frame may be derived from the MAP-Sch-Trigger 310. Figure 5 , the second AP 120 may transmit a scheduling indication including a preamble 515-a and an SI frame 520 occupying a first subchannel of a plurality of available subchannels, such as a first 20 MHz channel of a plurality of available 20 MHz channels. In this example, two subchannels are illustrated, and the second AP 120 has an unused second subchannel 525. Similarly, the third AP 130 may transmit a scheduling indication including a preamble 515-b and an SI frame 530 occupying the second subchannel, leaving the first subchannel as an unused subchannel 535. Thus, these different SI frames 520 and 530 will not interfere with each other and may be transmitted concurrently, which may more efficiently use time and frequency resources.

[0093] In some cases, the MAP-Sch-Trigger 310 may be transmitted by the first AP 110 as the TXOP owner AP to each of the other neighboring APs 120 and 130, and may trigger these other APs 120 and 130 to transmit SI frames 520 and 530, respectively. In some cases, the preambles 515-a and 515-b transmitted by each AP 120 and 130, respectively, may include an AP identifier (such as an AP identifier expressed using a short BSSID or a color code, or a reserved or unique association ID (AID)) and an indication of the subchannel of the SI frame. In some cases, the preamble 515 and the SI frames 520 and 530 may be formatted in a MAP-PPDU. In some cases, associated STAs of different APs can determine the subchannels used by their APs 110, 120, and 130 by decoding the preamble 515, and each STA in the associated BSS can tune to the subchannel assigned for its corresponding AP 120 or 130, and all information per STA (such as MAC information) can be carried within the SI frame.

[0094] The first AP 110 may determine resources for transmission of each AP 120 and 130 based on the SI frames 520 and 530. After the multi-AP scheduling phase, the first AP 110 may transmit a MAP-CT-Trigger 320 to initiate a coordinated transmission 325.

[0095] Figure 6 An example of downlink coordinated transmission in which interference may be a consideration is illustrated. As with other examples in the present disclosure, the first AP 110 may be Figure 6. The first AP 110 may provide a resource assignment for an OBSS to concurrently use a portion of a TXOP using coordinated transmission. In this example, the first STA 114 may have uplink data to be transmitted to the first AP 110 (shown as a first uplink transmission 611). Similarly, the second STA 124 may have uplink data to be transmitted to the second AP 120 (shown as a second uplink transmission 621). Even though the first STA 114 and the second STA 124 are associated with different APs, these uplink transmissions may be transmitted concurrently in different resource units of a wireless channel using the coordinated transmission techniques of the present disclosure. For example, the first AP 110 may provide a resource assignment to the second AP 120, and the second AP 120 may schedule a second uplink transmission 621 in the resource assignment. However, the second uplink transmission 621 may cause interference 622, which prevents the first AP 110 from correctly receiving the first uplink transmission 611. Even though the first uplink transmission 611 and the interference 622 may occupy different subbands or RUs of the coordinated transmission of the wireless channel, the interference 622 may exist. For example, when the second STA 124 is closer to the first AP 110 than the first STA 114 during the coordinated transmission, the interference 622 may be more prominent. Since the first AP 110 is the TXOP owner, it may be desirable to protect the first uplink transmission 611 from the interference 622.

[0096] According to an aspect of the present disclosure, the first AP 110 may make the use of the resource assignment conditional based on the amount of potential interference 622. The first AP 110 may communicate a parameter (CO-UL parameter) to the second AP 120, which further communicates the parameter to the second STA 124. The second STA 124 may use the CO-UL parameter to determine whether it can use the resource assignment without causing interference 622 that is higher than the amount that the first AP 110 can tolerate. Figure 8As further described in , the second STA 124 may measure the signal strength of the communication from the first AP 110, and use the measured signal strength and the CO-UL parameter to determine the maximum amount of transmit power that the second STA 124 can use for the second uplink transmission 621 (as the uplink power limit of the second STA 124). The second STA 124 may further determine an estimated transmit power for the second uplink transmission 621 that enables the second uplink transmission 621 to be correctly decoded by the second AP 120. If the estimated transmit power is lower than the uplink power limit, the second STA 124 may proceed to transmit the second uplink transmission 621. However, if the estimated transmit power is higher than the uplink power limit, the second STA 124 may determine that transmitting the second uplink transmission 621 will cause too much interference 622 so that the first AP 110 cannot correctly receive the first uplink transmission 611. In this scenario, the second STA 124 may refrain from using the resource assignment.

[0097] Figure 7 An example of downlink coordinated transmission in which interference may be a consideration is illustrated. As with other examples in the present disclosure, the first AP 110 may be Figure 7 . The first AP 110 may provide a resource assignment for an OBSS to concurrently use a portion of a TXOP using coordinated transmission. In this example, the first AP 110 may have downlink data to be transmitted to the first STA 114 (shown as a first downlink transmission 651). Similarly, the second AP 120 may have downlink data to be transmitted to the second STA 124 (shown as a second downlink transmission 652). Using the coordinated transmission techniques in the present disclosure, these downlink transmissions may be transmitted concurrently in different resource units of a wireless channel. For example, the first AP 110 may provide a resource assignment to the second AP 120, and the second AP 120 may schedule a second downlink transmission 652 in the resource assignment. However, the second downlink transmission 652 may cause interference 653, which prevents the first STA 114 from correctly receiving the first downlink transmission 651. Even though the first downlink transmission 651 and the interference 653 may occupy different subbands or RUs of the coordinated transmission of the wireless channel, the interference 653 may exist. For example, when the first STA 114 is closer to the second AP 120 than the first AP 110 during the coordinated transmission, the interference 653 may be more prominent. Since the first AP 110 is the TXOP owner, it may be desirable to protect the first downlink transmission 651 from the interference 653.

[0098] According to an aspect of the present disclosure, the first AP 110 may make the use of the resource assignment conditional based on the amount of potential interference 653. The first AP 110 may communicate a parameter (CO-DL parameter) to the second AP 120. The second AP 120 may use the CO-DL parameter to determine whether it can use the resource assignment without causing interference 653 above the amount that the first AP 110 can tolerate. In some implementations, the first AP 110 may also cause the first STA 114 (or any other target STA for which downlink traffic is to be sent) to send a test communication. The test communication may be a null packet, a quality of service null frame, or a newly defined type of frame for test communications. For example, the first AP 110 may send a null packet request trigger frame to the first STA 114 to cause the first STA 114 to send the test communication. The second AP 120 may obtain an RSSI measurement associated with the test communication from the first STA 114, even if the first STA 114 belongs to a first BSS different from the second AP 120. Using the RSSI measurement of the test communication and the CO-DL parameters, the second AP 120 can determine the maximum amount of transmit power that the second AP 120 can use for the second downlink transmission 652 (as the downlink power limit of the second AP 120). The second AP 120 can further determine an estimated transmit power for the second downlink transmission 652 that enables the second downlink transmission 652 to be correctly decoded by the second STA 124. If the estimated transmit power is below the downlink power limit, the second AP 120 can proceed to transmit the second downlink transmission 652. However, if the estimated transmit power is above the downlink power limit, the second AP 120 can determine that transmitting the second downlink transmission 652 will cause too much interference 653 for the first STA 114 to correctly receive the first downlink transmission 651. In this scenario, the second AP 120 can refrain from using the resource assignment.

[0099] Figure 8 An example of a protocol sequence 800 for uplink OFDMA supporting uplink coordinated transmission is illustrated. In this example, a first AP 110, a second AP 120, and a third AP 130 may perform uplink coordinated transmission. Since the first AP 110 is the TXOP owner for this example, the first AP 110 may transmit a scheduling trigger (such as a MAP-Sch-Trigger 810), which may be received by the second AP 120 and the third AP 120. The MAP-Sch-Trigger 810 may include a CO-UL parameter as a variable, which may be used by the OBSS STA to determine the uplink power limit. Figure 8 The example depicts the Figure 5. Other implementations may use sequential scheduling. In this case, the second AP 120 and the third AP 130 may perform multi-AP scheduling according to any of the examples discussed herein. For example, the second AP 120 and the third AP 130 may send SI frames 815 and 825 to their respective BSSs. In this example, the SI frames 815 and 825 may include CO-UL parameters. For example, the second AP 120 may obtain the CO-UL parameters from the MAP-Sch-Trigger 810 and transmit the CO-UL parameters to the STA that needs to transmit uplink data. After the multi-AP scheduling phase, the first AP 110 may determine the resources for uplink transmission from the OBSS STA to each neighboring AP 120 and 130 based on the multi-AP scheduling. In order to initiate uplink coordinated transmission, the first AP 110 may transmit a MAP-CT-Trigger 820 message. The OBSS STAs may measure the RSSI of the MAP-CT-Trigger 820 to determine variables in the power limit calculation, as further described below. For example, the second STA 124 may perform an RSSI measurement 885 with respect to the MAP-CT-Trigger 820. In some implementations, the SI frames 815 and 825 may include an AP identifier associated with the first AP 110 (such as an AP identifier expressed using a short BSSID or a color code, or a reserved or unique AID). For example, the second AP 120 may include a color code of the first AP 110 to assist its STAs (such as STAs of the second AP 120) in identifying the MAP-CT-Trigger 820 and obtaining RSSI measurements 885. The third STA 134 may perform a similar process (shown as RSSI measurement 887).

[0100] After MAP-CT-Trigger 820, APs 110, 120, and 130 may trigger uplink coordinated transmission. In this example, multi-AP coordinated transmission may use OFDMA to provide concurrent transmission of multiple APs 110, 120, and 130 and STAs, and uplink transmissions of these STAs may be triggered by corresponding triggers (such as triggers 830, 845, 860) from their respective APs. In this example, the first AP 110 may transmit a preamble across several subchannels, and may use a first subchannel (such as a primary 20 MHz channel) to transmit the trigger 830 while the remaining subchannels are idle. The trigger 830 may trigger the corresponding STA(s) (such as the first STA 114) to transmit a UL PPDU 835 in the first subchannel while the remaining subchannels are idle. The second AP 120 may transmit a preamble across several subchannels, and may use a second subchannel (such as a secondary 20 MHz channel) to transmit the trigger 845 while the remaining subchannels are idle. The trigger 845 may trigger the corresponding STA(s) (such as the second STA 124) to transmit the UL PPDU 850 in the second subchannel while the remaining subchannels are idle. The third AP 130 may transmit a preamble spanning several subchannels and may use a third subchannel (such as a secondary 40 MHz channel) to transmit the trigger 860 while the remaining subchannels are idle. The trigger 860 may trigger the corresponding STA(s) (such as the third STA 134) to transmit the UL PPDU 865 in all or a portion of the third subchannel while the remaining subchannels are idle. In some examples, the UL PPDUs on different subchannels may end at different times. In this example, as the TXOP owner, the first AP 110 may indicate the subchannels for each neighboring AP 120 and 130.

[0101] After a trigger from the first AP 110, the first STA 114 may proceed to its UL coordinated transmission. However, as described above, the second STA 124 and the third STA 134 may determine whether to proceed to (or refrain from) transmitting the UL PPDU 850 and UL PPDU 865 transmissions, respectively, based on whether these UL transmissions would exceed the uplink power limit. The uplink power limit may be calculated using the CO-UL parameters and the RSSI measurement 885 associated with the first AP 110.

[0102] The following is an example of how the CO-UL parameters may be calculated. The calculation is based on determining the maximum interference (I1) that the first AP 110 can allow from a neighboring BSS on its idle RU without compromising its ability to properly receive UL transmissions from the first STA 114. The maximum interference (I1) is based on the amount of transmit power of the second STA 124 minus the amount of path loss between the second STA 124 and the first AP 110.

[0103] I1 = T2 – PL 12, (1)

[0104] where T2 represents the Tx (transmit) power of the second STA 124 (for its UL transmission), and PL 12 represents the path loss from the second STA 124 to the first AP 110.

[0105] The path loss from the second STA 124 to the first AP 110 may be expressed as follows:

[0106] PL 12 = TA1 – R 12, (2)

[0107] Where TA1 represents the transmit power of the first AP 110 (for the MAP-CT-Trigger frame), and R 12 represents the received power of the first AP 110 measured by the second STA 124 (based on the RSSI measurement 885 for the MAP-CT-Trigger frame).

[0108] Combining equations (1) and (2), the equation for the maximum interference (I1) can thus be expressed as:

[0109] I1 = T2 – (TA1 – R 12 ). (3)

[0110] The second STA 124 may already know T2 (because T2 is related to the transmit power of the second STA 124). The first AP 110 may reorganize the equation to prepare the CO-UL parameters based on other variables known to the first AP 110:

[0111] T2 = (TA1 – R 12 ) + I1 (4)

[0112] T2 = (TA1 + I1) – R 12 ) (5)

[0113] Since the first AP 110 knows both TA1 and I1, it can calculate the CO-UL parameters based on these values.

[0114] CO-UL parameter = (TA1 + I1)(6)

[0115] R 12 The value of represents the received power of the first AP 110 measured by the second STA 124 (based on the RSSI measurement 885 for the MAP-CT-Trigger frame). Thus, the second STA 124 can measure this value.

[0116] Using the CO-UL parameter and R 12 , the second STA 124 can determine the uplink power limit (CO-UL parameter - R 12 ).

[0117] In process 890, the second STA 124 can determine the uplink power limit and the transmit power required for the second STA 124 to communicate with the second AP 120. If the transmit power of the second STA 124 is lower than the uplink power limit (e.g., T2 < CO-UL parameter - R 12 ), then the second STA 124 can proceed to perform uplink coordinated transmission using resource assignment. Other STAs (such as the third STA 134) can perform similar independent determinations (such as process 892) to determine whether to use resource assignment.

[0118] Fig. 9 An example of a protocol sequence 900 for downlink OFDMA to support downlink coordinated transmission is illustrated. In this example, the first AP 110, the second AP 120, and the third AP 130 can perform downlink coordinated transmission. Since the first AP 110 is the TXOP owner for this example, the first AP 110 can transmit a scheduling trigger, such as the MAP-Sch-Trigger 910. The MAP-Sch-Trigger 910 can include the CO-DL parameter as a variable that can be used by the OBSS AP to determine the downlink power limit. The MAP-Sch-Trigger 910 can be received by the second AP 120 and the third AP 130. The MAP-Sch-Trigger 910 can initiate the scheduling phase of multi-AP communication. Figure 8 The example of depicts as Figure 5915 and 925. In this example, the SI frames 915 and 925 may indicate downlink resources for each of the second AP 120 and the third AP 130, respectively.

[0119] In this example, as the TXOP owner, the first AP 110 may indicate the subchannels for each neighboring AP 120 and 130. Such an indication may be provided in the MAP-Sch-Trigger 910, and the second AP 120 and the third AP 130 may use the allocated subchannels to serve their STAs. In some cases, the subchannels used for data communication may be different from the subchannels assigned to send SI frames during the multi-AP scheduling phase in the example of providing concurrent transmission of SI frames. In some cases, each neighboring AP may select the STAs that will be served during the coordinated OFDMA phase, and the SI frames may be used to provide an indication of the selected STAs (the first AP 110 may not be aware of the list of selected STAs). In some examples, as part of the multi-AP scheduling, the second AP 120 and the third AP 130 may transmit SI frames to the STAs selected to be served during the coordinated OFDMA period, and the RUs assigned to the APs within the subchannels are assigned by the first AP 110 as the TXOP owner. In some cases, the first AP 110 may use the MAP-Sch-Trigger 910 frame to assign subchannels for coordinated OFDMA transmissions.

[0120] In this example, the coordinated OFDMA transmission is initiated in response to a MAP-CT-Trigger 920. The MAP-CT-Trigger 920 may provide scheduling information about the coordinated OFDMA, which may include subchannel assignments for each participating AP 110, 120, and 130 for use when transmitting uplink coordinated transmissions. In some cases, the subchannel assignments may be provided in the MAP scheduling trigger 910, and these assignments may be carried to the coordinated OFDMA communication. In other cases, the first AP 110 may assign subchannels at the time of scheduling so that resources can be allocated more efficiently. In this example, multi-AP coordinated transmissions may use OFDMA to provide concurrent transmissions of multiple APs 120 and 130. In this example, the first AP 110 may transmit a preamble that spans several subchannels, and may use a first subchannel (such as a primary 20 MHz channel) to transmit (all) DLPSDU 930 while the remaining subchannels are idle. The second AP 120 may transmit a preamble across several channels and may use a second subchannel (such as a secondary 20 MHz channel) to transmit PSDU(s) 940 while the remaining subchannels are idle. Similarly, the third AP 130 may transmit a preamble across several subchannels and may use a third subchannel (such as a secondary 40 MHz channel) to transmit PSDU(s) 950 while the remaining subchannels are idle.

[0121] like Figure 7As described in , coordinated transmissions (such as DL PSDU(s) 940 or DL ​​PSDU(s) 950) may interfere with downlink transmissions from the first AP 110 to the first STA 114. Therefore, the second AP 120 and the third AP 130 may determine whether to transmit the transmissions based on whether the DL PSDU(s) 940 and DL PSDU(s) 950 transmissions may cause interference above a threshold amount. The CO-DL parameter included in the MAP-Sch-Trigger 910 may be a value calculated by the first AP 110 for use by the second AP 120 and the third AP 130 in determining an uplink power limit. For example, the downlink power limit may be calculated using the CO-DL parameter and the RSSI measurement 980 associated with the test communication from the first STA 114. For example, if the first AP 110 has downlink traffic for the first STA 114, the first AP 110 may facilitate a test communication from the first STA 114 that may be detected and measured by the second AP 120 and the third AP 130. The first AP 110 may transmit a null packet request (such as NP-REQ 905) to the first STA 114. In response to the NP-REQ 905, the first STA 114 may transmit a test communication (such as a null packet NP 925). The second AP 120 may detect the SI frame 925 and obtain an RSSI measurement 980. The RSSI measurement 980 may be a variable that, along with the CO-DL parameter, may be used by the second AP 120 to determine the downlink power limit of its downlink coordinated transmission (such as (s) DL PSDU 940). The third AP 130 may perform a similar process (shown as RSSI measurement 982).

[0122] The following is an example of how the CO-DL parameters may be calculated. The calculation is based on the transmit power of the first AP 110 and the neighboring APs and the path loss between the first STA 114 and the neighboring APs. The CO-DL parameters may be calculated as variable inputs that may be used by each neighboring AP along with its independent RSSI measurements 980, 982 about the first STA 114. The CO-DL parameters are premised on an initial formula that describes a goal of having the transmit power of the first AP 110 be greater than the transmit power of the neighboring APs plus a margin to accommodate interference. The initial goal may be represented by equation (7):

[0123] (T1 – PL1) > (T2 – PL2) + K, (7)

[0124] Wherein T1 represents the Tx power of the first AP 110 for DL ​​coordinated transmission that the AP needs to send to the first STA 114,

[0125] T2 represents the Tx power of the second AP 120 for DL ​​coordinated transmission to one STA associated with the second AP 120,

[0126] PL1 represents the path loss from the first AP 110 to the first STA 114,

[0127] PL2 represents the path loss from the second AP 120 to the first STA 114, and

[0128] K represents a margin determined by the TXOP owner. The margin may be statically or dynamically determined. For example, the value of K may be dynamically determined based on a history of channel quality associated with a wireless channel. Alternatively, the value of K may be system-configured, user-configured, or manufacturer-configured.

[0129] The initial objective formula (7) may be reorganized to isolate T2, which is a value that the first AP 110 may not know, but the second AP 120 does.

[0130] T2 < T1 – (PL1 – PL2) – K (8)

[0131] The metric of path loss may be reduced to a value-based RSSI measurement associated with the SI frame 925 from the first STA 114:

[0132] PL1 – PL2 = (T s –PL2) – (T s – PL1) = Rx2 – Rx1 (9)

[0133] Where T s represents the Tx power of the SI frame 925 measured by the first STA 114,

[0134] Rx1 represents the Rx (received) power of the SI frame 925 measured by the first AP 110 , and Rx2 represents the Rx power of the SI frame 925 measured by the second AP 120 .

[0135] Using the equivalent variables in equation (9) to replace the path loss variables in equation (8), the objective equation can be written as equation (10) and reorganized as equation (11):

[0136] T2 < T1 – (Rx2 – Rx1) – K (10)

[0137] T2 < (T1 + Rx1 – K) – Rx2 (11)

[0138] Since the first AP 110 knows the values of T1, Rx1, and K, it can calculate the CO-DL parameter based on these values.

[0139] CO-DL = (T1 + Rx1 – K) (12)

[0140] In some implementations, the first AP 110 may send the CO-DL parameter in the MAP-CT-Trigger 920. Alternatively, the first AP 110 may calculate the CO-UL parameter before the MAP-Sch-Trigger 910 and include the CO-UL parameter in the MAP-Sch-Trigger 910. For example, the first AP 110 may facilitate test communication (SI frame 925) before starting the multi-AP scheduling phase.

[0141] In process 985, the second AP 120 may determine the downlink power limit based on the RSSI measurement 980 for the SI frame 925 and determine the transmit power required for the second AP 120 to communicate with the second STA 124. If the transmit power of the second AP 120 is lower than the downlink power limit (e.g., T2 < CO-DL parameter - Rx1), then the second AP 120 may proceed to perform downlink coordinated transmission using resource assignment. Otherwise, the second AP 120 may refrain from using resource assignment. Other APs (such as the third AP 130) may perform similar independent determinations (such as process 987) to determine whether to use their resource assignments.

[0142] Fig. 10A An example of a multi-AP physical protocol data unit (MAP PPDU) 1000 is illustrated. In this example, the MAP PPDU 1000 may reuse the defined format of the HE MU PPDU, which may include an L-STF field 1004, an L-LTF field 1008, an L-SIG field 1012, an RL-SIG field 1016, a HE-SIG-A field 1020, a HE-SIG-B field 1024, a HE-STF field 1028, one or more HE-LTF fields 1032 to 1036, a data section 1040, and a packet extension (PE) field 1044. In this example, the MAP PPDU 1000 may use the STA ID fields of the HE-SIG-B field 1024 to carry the identifier of each neighboring AP (e.g., an identifier determined from the short BSSID, a color code, or a reserved or unique AID value of these APs).

[0143] In some cases, the STA-ID field of the HE-SIG B 1024 may carry the AID of the STA. In some cases, for the purpose of coordinated reuse, the STA-ID may be overloaded to carry the BSS identifier of the AP so that the STA associated with the BSS decodes the corresponding resource unit. In some cases, one or more fields in the HE-SIG-A 1020 may indicate whether the HE-SIG-B field 1024 has an alternative interpretation. For example, by setting the BSS color field in the SIG-A to a reserved or unique value (e.g., color = 63). In other examples, the UL flag in the SIG-A may be used (in legacy systems, the flag may be set to 1 in the case of STA UL to AP and may be set to 0 in the case of AP DL to STA, and in both cases the STA-ID may be set to the AID of the intended STA, so that the transmitting AP will not set UL to 1). For example, the AP may set UL to 1 in the MU PPDU to indicate that the STA-ID carries the BSS identifier. The BSS identifier may be set to, for example, a random AID value picked by each AP and advertised in the AP's beacon to inform associated STAs, derived based on the AP's BSSID (such as by each STA applying a hash function to the BSSID), or a BSS color indication.

[0144] Fig. 10BAnother example of a multi-AP physical protocol data unit 1050 is illustrated. In this example, the MAP PPDU 1050 may modify the format of the defined HE TB PPDU, which may include an L-STF field 1054, an L-LTF field 1058, an L-SIG field 1062, an RL-SIG field 1066, a HE-SIG-A field 1070, a HE-STF field 1074, one or more HE-LTF fields 1078 to 1082, a data portion 1086, and a packet extension (PE) field 1090. In this example, the MAP PPDU 1050 may have a new field (such as HE-SIG-C) defined as a preamble to carry an AP identifier to a subchannel mapping. In other examples, the MAP PPDU 1050 may reuse the HE TB PPDU by reusing certain reserved / unused fields. For example, the spatial reuse field of the HE-SIG-A may be used to carry the AP identifier and the subchannel mapping. In a further example, a new EHT PPDU format may be defined to provide information as discussed for the MAP PPDU. For example, the SR bit in the HE-SIG-A field 1070 may be used to provide coordinated transmission information. In such a case, 25+1 of the 25+1 bits are available and may be used to carry information such as an indication of a new interpretation of the SIG-A (1 bit) (such as bit 23) BSS color (such as 6 bits per BSS) or subchannels available for reuse (16 bits, with 1 bit for each 20 MHz of the 320 MHz BW).

[0145] In some cases, in order to ensure that the HE-SIG-A and HE-SIG-B fields sent by all APs are the same, the TXOP owner AP may explicitly or implicitly send the content of HE SIG-A and HE-SIG-BA to neighboring APs, and may set the BSS color in HE-SIG-A to a single value (e.g., color 0).

[0146] Fig.11 A conceptual diagram of an example message format for communicating one or more parameters for coordinated transmission is shown. For example, a message may be sent from a first AP 110 to a second AP 120 or from a second AP 120 to one of its STAs. The message format 1100 may be used to communicate parameters that define conditions or provisions (also referred to as preconditions) for an OBSS to utilize resource assignments in a coordinated transmission. Fig.11An example data frame 1120 is included. The data frame 1120 may include a preamble 1122, a frame header 1124, a frame body 1110, and a frame check sequence (FCS) 1126. If the preamble 1122 is included, the preamble 1122 may include one or more bits for establishing synchronization. In some WLANs where synchronization can be established by conventional communications, the preamble 1122 may be omitted. The frame header 1124 may include source and destination network addresses (such as the network addresses of the sender AP and the receiver AP, respectively), the length of the data frame, or other frame control information. The frame body 1110 may be organized in a message format and may include a variety of fields or information elements 1132, 1136, and 1138.

[0147] Fig.11 100. An example information element 1160 is shown in FIG. The example information element 1160 includes a field 1162 with CO-UL parameters, a field 1164 with CO-DL parameters, and a field 1166 with resource assignments. In some implementations, the first AP 110 (as the TXOP owner) may send the CO-UL parameters or the CO-DL parameters in the MAP-Sch-Trigger message. Alternatively, the first AP 110 may send both the CO-UL parameters and the CO-DL parameters.

[0148] Fig.12 1 shows a block diagram of an example wireless communication device 1200. In some implementations, the wireless communication device 1200 may be a STA (such as the one described above with reference to Figure 1A and 1B In some implementations, the wireless communication device 1200 may be an example of a device used in an AP (such as one of the STAs 104, 114, 124, and 134 described above). Figure 1A and 1B An example of a device used in the described APs 102, 110, 120, and 130. The wireless communication device 1200 is capable of transmitting (or outputting for transmission) and receiving wireless communications (e.g., in the form of wireless packets). For example, the wireless communication device can be configured to: transmit and receive packets in the form of physical layer convergence protocol (PLCP) protocol data units (PPDUs) and media access control (MAC) protocol data units (MPDUs) that comply with IEEE 802.11 wireless communication protocol 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).

[0149] The wireless communication device 1200 may be or may include a chip, system on chip (SoC), chipset, package, or device including one or more modems 1202 (e.g., Wi-Fi (IEEE 802.11 compatible) modems). In some implementations, the one or more modems 1202 (collectively referred to as "modems 1202") additionally include a WWAN modem (e.g., a modem compatible with 3GPP 4G LTE or 5G). In some implementations, the wireless communication device 1200 also includes one or more radios 1204 (collectively referred to as "radios 1204"). In some implementations, the wireless communication device 1206 further includes one or more processors, processing blocks, or processing elements 1206 (collectively referred to as "processors 1206"), and one or more memory blocks or elements 208 (collectively referred to as "memory 1208").

[0150] The modem 1202 may include an intelligent hardware block or device, such as, for example, an application specific integrated circuit (ASIC), etc. The modem 1202 is generally configured to implement the PHY layer. For example, the modem 1202 is configured to modulate packets and output the modulated packets to the radio 1204 for transmission on the wireless medium. The modem 1202 is similarly configured to obtain the modulated packets received by the radio 1204 and demodulate the packets to provide demodulated packets. In addition to the modulator and demodulator, the modem 1202 may further include a digital signal processing (DSP) circuit system, an automatic gain control (AGC), an encoder, a decoder, a multiplexer, and a demultiplexer. For example, when in a transmission mode, the data obtained from the processor 1206 is provided to an encoder, which encodes the data to provide coded bits. The coded bits are then mapped (using the selected MCS) to points in the modulation constellation to provide modulated symbols. The modulated symbols may then be mapped to NSS number of spatial streams or NSTS number of space-time streams. The modulated symbols in the corresponding spatial stream or space-time stream 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 1204. In an implementation involving beamforming, the modulated symbols in the corresponding spatial stream are precoded via a steering matrix before being provided to the IFFT block.

[0151] When in receive mode, a digital signal received from the radio 1204 is provided to a DSP circuit system, which is configured to capture the received signal, for example, by detecting the presence of the received signal and estimating the initial timing and frequency offset. The DSP circuit system is further configured to digitally condition the digital signal, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correction for I / O imbalance), and applying digital gain to ultimately obtain a narrowband signal. The output of the DSP circuit system may then be fed to an AGC, which is configured to determine an appropriate gain using information extracted from the digital signal, for example, in one or more received training fields. The output of the DSP circuit system is also coupled to a demodulator, which is configured to extract 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 may 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 1206) for processing, evaluation, or interpretation.

[0152] The radio 1204 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 may include various DSP circuit systems, which include 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 1200 may 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 codewords output from the modem 1202 are provided to the radio 1204, which then transmits the codewords via the coupled antennas. Similarly, the codewords received via the antennas are obtained by the radio 1204, which then provides the codewords to the modem 1202.

[0153] The processor 1206 may include an intelligent hardware block or device, such as, for example, 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, discrete hardware components, or any combination thereof. The processor 1206 processes information received through the radio 1204 and the modem 1202, and processes information to be output by the modem 1202 and the radio 1204 for transmission over a wireless medium. For example, the processor 1206 may implement a control plane and a MAC layer, which is 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 encoding and decoding of frames, spatial multiplexing, space time block coding (STBC), beamforming, and OFDMA resource allocation, as well as other operations or techniques. In some implementations, the processor 1206 may generally control the modem 1202 so that the modem performs the various operations described above.

[0154] The memory 1204 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 1204 may also store non-transient processor or computer executable software (SW) code containing instructions that, when executed by the processor 1206, cause the processor to perform various operations for wireless communication described herein, including generation, transmission, reception, and interpretation of MPDUs, 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.

[0155] Fig.13A A block diagram of an example AP 1302 is shown. For example, the AP 1302 may be a reference Figure 1A and 1B 102, 110, 120, and 130 are described as example implementations. AP 1302 includes a wireless communication device (WCD) 1310 (although AP 1302 itself may also be generally referred to as a wireless communication device, as used herein). For example, wireless communication device 1310 may be a wireless communication device (WCD) 1310. Fig.12An example implementation of the wireless communication device 1200 described. The AP 1302 also includes a plurality of antennas 1320 coupled to the wireless communication device 1310 to transmit and receive wireless communications. In some implementations, the AP 1302 additionally includes an application processor 1330 coupled to the wireless communication device 1310, and a memory 1340 coupled to the application processor 1330. The AP 1302 further includes at least one external network interface 1350 that enables the AP 1302 to communicate with a core network or a backhaul network to obtain access to an external network (including the Internet). For example, the external network interface 1350 may include one or both of a wired (e.g., Ethernet) network interface and a wireless network interface (such as a WWAN interface). Some of the foregoing components may communicate directly or indirectly with other components on at least one bus. The AP 1302 further includes a housing that covers at least portions of the wireless communication device 1310, the application processor 1330, the memory 1340, and the antennas 1320 and the external network interface 1350.

[0156] Fig. 13B 1 shows a block diagram of an example STA 1304. For example, STA 1304 may be a reference Figure 1A and 1B 104, 114, 124, and 134 are described as example implementations. STA 1304 includes a wireless communication device 1315 (although STA 1304 itself may also be generally referred to as a wireless communication device, as used herein). For example, wireless communication device 1315 may be a wireless communication device as described herein. Fig.12 An example implementation of the wireless communication device 1200 described herein. The STA 1304 also includes one or more antennas 1325 coupled to the wireless communication device 1315 to transmit and receive wireless communications. The STA 1304 additionally includes an application processor 1335 coupled to the wireless communication device 1315, and a memory 1345 coupled to the application processor 1335. In some implementations, the STA 1304 further includes a user interface (UI) 1355 (such as a touch screen or keypad) and a display 1365, which can be integrated with the UI 1355 to form a touch screen display. In some implementations, the STA 1304 can further include one or more sensors 1375, such as, for example, one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors. Some of the foregoing components can communicate directly or indirectly with other components on at least one bus. STA 1304 further includes a housing that covers the wireless communication device 1315 , the application processor 1335 , the memory 1345 , and at least portions of the antenna 1325 , the UI 1355 , and the display 1365 .

[0157] Various implementations of the present disclosure generally relate to coordinated transmissions by different WLANs during a TXOP of a wireless channel. In some aspects of the present disclosure, a scheme for multi-AP scheduling is provided, in which a first AP can obtain channel access and become a TXOP owner. The TXOP owner can provide resource assignments in the TXOP for use by a neighboring AP (such as another AP of another BSS that is not the TXOP owner of the TXOP). During the coordinated transmission, the first WLAN and the second WLAN can communicate concurrently using different resources of the wireless channel. According to the present disclosure, an uplink power limit or a downlink power limit can be determined by an OBSS. Parameters (such as CO-UL parameters or CO-DL parameters) can be calculated and provided by the TXOP owner. The parameters are values ​​that can be shared with an OBSS AP or OBSS STA. The OBSS AP or OBSS STA can use the parameters and RSSI measurements from the BSS of the TXOP owner to determine the uplink power limit or the downlink power limit. If the OBSS AP or OBSS STA can send a coordinated transmission with a transmit power below the uplink power limit or the downlink power limit, the OBSS AP or OBSS STA may proceed to use resource assignment for coordinated transmission. Otherwise, if the OBSS AP or OBSS STA requires a transmit power above the uplink limit or the downlink limit, the OBSS AP or OBSS STA may refrain from using resource assignment for coordinated transmission.

[0158] Specific implementations of the subject matter described in the present disclosure may be implemented to achieve one or more of the following potential advantages. A first AP (as a TXOP owner) may share a frequency portion of a TXOP (as a resource assignment) with a second AP (a neighboring AP) for coordinated transmissions during a portion of the TXOP. The second AP may use the resource assignment in circumstances where the second AP's use of the resource assignment will not interfere with the first AP's use of the TXOP. Thus, the TXOP owner is not penalized for sharing a portion of the TXOP, while the use of coordinated transmissions may improve the spectral efficiency of the wireless channel. Furthermore, in some implementations, the use of coordinated transmissions may be implemented without direct management or backhaul coordination by different WLANs sharing the wireless channel. The use of a CO-UL parameter or a CO-DL parameter may represent a concise metric that provides sufficient information for a second WLAN to determine whether to participate in coordinated transmissions.

[0159] Fig.14A flow chart illustrating an example process for coordinated transmission performed by a first AP according to some implementations is shown. In some implementations, process 1400 may be performed by a TXOP owner (such as first AP 110 in the examples of the present disclosure). In some implementations, process 1400 begins in block 1410 by communicating a multi-AP scheduling trigger (MAP-Sch-Trigger) message during a first portion of a transmission opportunity of a wireless channel. The first AP may be a controller of the transmission opportunity. For example, the first AP may win a contention-based procedure to become the TXOP owner of the TXOP.

[0160] At block 1420, process 1400 proceeds to provide a resource assignment to the second AP for use for coordinated transmission on the wireless channel during a second portion of the transmission opportunity. The resource assignment may be conditionally available for use by the second WLAN based at least in part on an amount of interference that use of the resource assignment by the second WLAN would cause to the first WLAN.

[0161] At block 1430, process 1400 proceeds to communicate a Multi-AP Coordinated Transmission Trigger (MAP-CT-Trigger) message to indicate the start of the second portion of the transmission opportunity.

[0162] At block 1440, process 1400 proceeds to communicate between the first AP and at least a first station (STA) via coordinated transmissions during a second portion of the transmission opportunity. The first STA may be associated with the first AP and a portion of the first WLAN.

[0163] In some implementations, coordinated transmissions may be configured for concurrent uplink communications from a first STA to a first AP and from a second STA to a second AP. The condition may be configured to prevent the second STA from using a resource assignment if the second STA's use of the resource assignment would cause interference to the first AP above a threshold.

[0164] In some implementations, process 1400 includes communicating the CO-UL parameter in a MAP-Sch-Trigger message.The CO-UL parameter can be based at least in part on an amount of interference that the first AP will tolerate due to the second WLAN using the resource assignment.

[0165] Fig.15A flow chart illustrating another example process for coordinated transmission performed by a first AP according to some implementations is shown. In some implementations, process 1500 may be performed by a TXOP owner (such as first AP 110 in the examples of the present disclosure). In some implementations, process 1500 begins in block 1510 by transmitting a multi-AP scheduling trigger (MAP-Sch-Trigger) message to a plurality of APs during a first portion of a transmission opportunity. The plurality of APs may include one or more second APs of one or more respective second BSSs.

[0166] At block 1530, process 1500 proceeds to receive one or more scheduling indications from the one or more second APs in response to the MAP-Sch-Trigger message.

[0167] In box 1540, process 1500 proceeds to allocate resources to the one or more second APs for coordinated transmission on the wireless channel during the second part of the transmission opportunity based on the scheduling indication, and the resources allocated to each of the one or more second APs are available to the second AP or the second STA subject to the condition of the corresponding transmission power of the corresponding second AP or the corresponding second station (STA) of the corresponding second BSS.

[0168] At block 1550 , process 1500 proceeds to transmit a Multi-AP Coordinated Transmission Trigger (MAP-CT-Trigger) message to the plurality of APs to indicate the allocated resources and the start of the second portion of the transmission opportunity.

[0169] At block 1560, process 1500 proceeds to transmit or receive data to or from at least a first STA of the first BSS as part of the coordinated transmission during the second portion of the transmission opportunity.

[0170] Fig.16 A flow chart illustrating an example process 1600 for coordinated transmission performed by a second AP according to some implementations is shown. In some implementations, the process 1600 may be performed by a neighboring AP, such as the second AP 120 in the examples of the present disclosure. In some implementations, the process 1600 begins in block 1610 by receiving a multi-AP scheduling trigger (MAP-Sch-Trigger) message from a first AP during a first portion of a transmission opportunity of a wireless channel, where the first AP is a controller of the transmission opportunity.

[0171] At block 1620, process 1600 proceeds to determine a resource assignment provided by the first AP for use by the second WLAN for coordinated transmission on the wireless channel during a second portion of the transmission opportunity. The resource assignment may be conditionally available for use by the second WLAN based at least in part on an amount of interference that use of the resource assignment by the second WLAN would cause to the first WLAN.

[0172] At block 1630, process 1600 proceeds to receiving a MAP-CT-Trigger message to indicate the start of the second portion of the transmission opportunity.

[0173] At block 1640 , the process 1600 proceeds to communicate between the second AP and at least a second STA concurrently with the communication between the first AP and the first STA via the coordinated transmission during a second portion of the transmission opportunity.

[0174] In some implementations, coordinated transmission is configured for concurrent uplink communications from a first STA to a first AP and from a second STA to a second AP. The condition may be configured to prevent the second STA from using the resource assignment if the second STA's use of the resource assignment would cause interference to the first AP above a threshold.

[0175] In some implementations, coordinated transmission is configured for concurrent downlink communications from the first AP to the first STA and from the second AP to the second STA. The condition can be configured to prevent the second AP from using the resource assignment if the second AP's use of the resource assignment would cause interference to the first STA above a threshold.

[0176] Fig.17 A flow chart illustrating an example process 1700 for coordinated transmission performed by a second AP according to some implementations is shown. In some implementations, the process 1700 may be performed by a neighboring AP (such as the second AP 120 in the examples of the present disclosure). In some implementations, the process 1700 begins in block 1710 by receiving a multi-AP scheduling trigger (MAP-Sch-Trigger) message from a first AP of a first BSS during a first portion of a transmission opportunity of a wireless channel. For example, the first AP may be a controller of the transmission opportunity.

[0177] At block 1720 , process 1700 proceeds to transmit one or more scheduling indications from the second AP to the first AP in response to the MAP-Sch-Trigger message.

[0178] In box 1730, process 1700 proceeds to receiving a multi-AP coordinated transmission trigger (MAP-CT-Trigger) message from the first AP, wherein the MAP-CT-Trigger message indicates the allocated resources and the start of the second part of the transmission opportunity, the allocated resources are allocated by the first AP based on the scheduling indication for coordinated transmission on the wireless channel during the second part of the transmission opportunity, and the resources allocated to the second AP are subject to the condition of the corresponding transmission power of the second AP or the second station (STA) based on the second BSS and are available to the second AP or the second STA.

[0179] In block 1740, the process 1700 proceeds to transmit or receive data to or from at least a second STA concurrently with the communication between the first AP and the first STA as part of the coordinated transmission during the second portion of the transmission opportunity using the allocated resources.

[0180] Fig.18 A flow chart illustrating an example process 1800 for coordinated transmission performed by STAs associated with neighboring APs according to some implementations is shown. In some implementations, the process 1800 may be performed by a STA of a neighboring AP, such as the second STA 124 in the examples of the present disclosure. In some implementations, the process 1800 begins in block 1810 by receiving a message during a first portion of a transmission opportunity and from a second AP, the message including allocated resources of the transmission opportunity for coordinated transmission during a second portion of the transmission opportunity controlled by a first AP of a first BSS.

[0181] At block 1820, process 1800 proceeds to determine at least one condition for preventing use of the allocated resources based on whether the transmit power of the second STA would cause interference above a threshold amount to communications between the first AP and a first STA associated with the first AP.

[0182] In block 1830 , process 1800 proceeds to transmit data from the second STA to the second AP concurrently with communication between the first STA and the first AP as part of a coordinated transmission during a second portion of the transmission opportunity based on the at least one condition being satisfied.

[0183] In some implementations, the condition is based on a CO-UL parameter and a transmit power setting of the second STA. For example, the second STA may receive the CO-UL parameter and an identifier of the first AP along with a scheduling indicator. The second STA may use the identifier of the first AP to detect a multi-AP coordinated transmission trigger (MAP-CT-Trigger) message transmitted from the first AP. The second STA may measure the signal strength of the MAP-CT-Trigger message. The second STA may determine the uplink power limit of the coordinated transmission from the second STA to the second AP based at least in part on the signal strength and the CO-UL parameter. The second STA may determine whether the condition is met based at least in part on the uplink power limit and the transmit power setting of the second STA. For example, if the transmit power setting of the second STA is lower than the uplink power limit, the condition may be met.

[0184] Fig.19 A block diagram of an example AP 1900 according to some implementations is shown. For example, the AP 1900 may be an example of aspects of the AP 102, the AP 1302, the first AP 110, the second AP 120, or the third AP 130 described with reference to other figures of the present disclosure. The AP 1900 is capable of transmitting and receiving wireless communications (e.g., in the form of wireless packets) and encoding and decoding such communications. For example, the wireless communications may include Wi-Fi packets that include frames that comply with IEEE 802.11 standards (such as those defined by the IEEE 802.11-2016 specification or its revisions, including but not limited to 802.11ah, 802.11ay, 802.11ax, 802.11az, and 802.11ba). The AP 1900 includes at least one processor 1910 (collectively referred to as "processor 1910"), at least one memory 1920 (collectively referred to as "memory 1920"), at least one modem 1930 (collectively referred to as "modem 1930"), at least one antenna 1940 (collectively referred to as "antenna 1940"), at least one external network interface 1950 (collectively referred to as "network interface 1950"), and in some instances, a user interface (UI) 1960. Fig.19 Each component (or "module") described may communicate directly or indirectly with other components on at least one bus 1905. Although illustrated as being coupled to the bus 1905, the memory 1920 may also be coupled to the processor 1910.

[0185] The processor 1910 may include an intelligent hardware device, such as, for example, a central processing unit (CPU), a microcontroller, an application specific integrated circuit (ASIC), or a programmable logic device (PLD) (such as a field programmable gate array (FPGA)), etc. The processor 1910 processes information received through the modem 1930 and the external network interface 1930. The processor 1910 may also process information to be sent to the modem 1930 for transmission through the antenna 1940 and information to be sent to the external network interface 1930. The processor 1910 may generally be configured to perform various operations related to generating and transmitting downlink frames and receiving uplink frames.

[0186] The memory 1920 may include random access memory (RAM) and read-only memory (ROM). The memory 1920 may also store processor or computer executable software (SW) code containing instructions that, when executed by the processor 1910, cause the processor to perform various functions described herein for wireless communications, including generation and transmission of downlink frames and reception of uplink frames.

[0187] The modem 1930 is generally configured to modulate packets and provide the modulated packets to the antenna 1940 for transmission, and to demodulate packets received from the antenna 1940 to provide demodulated packets. The modem 1930 generally includes or is coupled to at least one radio frequency (RF) transmitter and at least one RF receiver, which can be combined into one or more transceivers, and the one or more transceivers are in turn coupled to one or more antennas 1940. For example, in some AP implementations, the AP 1900 may include multiple transmit antennas (each with a corresponding transmit chain) and multiple receive antennas (each with a corresponding receive chain). The modem 1930 can communicate with at least one wireless device (such as a wireless device) via the antenna 1940. Figure 1B The first STA 114 described performs bidirectional communication.

[0188] The modem 1930 may include a digital processing circuit system, an automatic gain control (AGC), a demodulator, a decoder, and a demultiplexer. The digital signal received from the transceiver is provided to the digital signal processing circuit system, which is configured to capture the received signal, for example, by detecting the presence of the received signal and estimating the initial timing and frequency offset. The digital signal processing circuit system is further configured to digitally condition the digital signal to ultimately obtain a narrowband signal, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correction for I / O imbalance), and applying digital gain. The output of the digital signal processing circuit system is fed to the AGC, which is configured to determine the appropriate gain using information extracted from the digital signal, for example, in one or more received training fields. The output of the digital signal processing circuit system is also coupled to a demodulator, which is configured to extract modulated symbols from the signal and reversely map the symbols to points in the modulation constellation to provide demodulated bits. The demodulator is coupled to a decoder that is configured to decode the demodulated bits to provide decoded bits, which are then fed to a demultiplexer for demultiplexing. The demultiplexed bits may then be provided to a processor 1910 for processing, evaluation, or interpretation, for example, by one or more host applications executing on the processor.

[0189] The AP 1900 may communicate with a core or backhaul network to obtain access to an external network including the Internet through an external network interface 1950. For example, the external network interface 1950 may include one or both of a wired (e.g., Ethernet) network interface or a wireless (e.g., LTE, 4G, or 5G) network interface.

[0190] The AP 1900 may include a coordinated transmission control unit 1970. The coordinated transmission control unit 1970 may implement any coordinated transmission technology described in the present disclosure. For example, the coordinated transmission control unit 1970 in the first AP 190 may be configured to make resource assignments to neighboring APs. The coordinated transmission control unit 1970 may determine one or more parameters (such as CO-UL parameters or CO-DL parameters, or both) and transmit them to the neighboring APs. According to various implementations of the present disclosure, the coordinated transmission control unit 1970 in the neighboring AP (such as the second AP 120) may use these parameters to determine whether to use resource assignments. In some implementations, the coordinated transmission control unit 1970 may be distributed within the processor 1910, the memory 1920, and the bus 1905. The memory 1920 may include computer instructions that can be executed by the processor 1910 to implement the functionality of the coordinated transmission control unit 1970. Any of these functionalities may be implemented partially (or completely) in hardware or on the processor 1910.

[0191] Fig. 20 A block diagram of an example STA 1200 according to some implementations is shown. For example, the wireless device 2000 may be an example of aspects of the STA 104, STA 1304, first STA 114, or second STA 124 described with reference to other figures in the present disclosure. The wireless device 2000 may be capable of transmitting and receiving wireless communications and encoding and decoding such communications. The wireless communications may follow any of a number of different wireless communication protocols. For example, the wireless device 2000 may be capable of transmitting and receiving Wi-Fi packets that include frames that follow the IEEE 802.11 standard (such as a standard defined by the IEEE 802.11-2016 specification or a revision thereof, including but not limited to 802.11ah, 802.11ay, 802.11ax, 802.11az, and 802.11ba). Additionally or alternatively, the wireless device 2000 may be capable of transmitting and receiving Bluetooth packets that follow the Bluetooth standard (such as in IEEE 802.15 or defined by the Bluetooth SIG). Additionally or alternatively, the wireless device 2000 may be capable of transmitting and receiving wireless packets associated with Long Term Evolution (LTE), Advanced International Mobile Telecommunications (IMT-Advanced) 4G or 5G standards.

[0192] The wireless device 2000 includes at least one processor 2010 (collectively referred to as “processor 2010”), at least one memory 2020 (collectively referred to as “memory 2020”), at least one modem 2030 (collectively referred to as “modem 2030”), and at least one antenna 2040 (collectively referred to as “antenna 2040”). In some implementations, the wireless device 2000 additionally includes some or all of the following: a user interface (UI) 2050 (such as a touch screen or a keypad), one or more sensors 2070 (such as one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors), and a display 2080. Fig. 20 Each of the components (or “modules”) described may communicate with each other directly or indirectly over at least one bus 2005. Although illustrated as being coupled to the bus 2005, the memory 2020 may also be coupled to the processor 2010.

[0193] The processor 2010 includes an intelligent hardware device such as, for example, a CPU, a microcontroller, an ASIC or a PLD (such as an FPGA), etc. The processor 2010 processes information received through the modem 2030 and information to be sent to the modem 2030 for transmission through the antenna 2040. The processor 2010 may be configured to perform various operations related to receiving a downlink frame and generating and transmitting an uplink frame.

[0194] The memory 2020 may include RAM and ROM. The memory 2020 may also store processor or computer executable SW code containing instructions that, when executed, cause the processor 2010 to perform various functions described herein for wireless communication, including reception of downlink frames and generation and transmission of uplink frames.

[0195] The modem 2030 is generally configured to modulate packets and provide the modulated packets to the antenna 2040 for transmission, and to demodulate packets received from the antenna 2040 to provide demodulated packets. The modem 2030 generally includes or is coupled with at least one radio frequency (RF) transmitter and at least one RF receiver, which can be combined into one or more transceivers, and the one or more transceivers are further coupled to one or more antennas 2040. For example, in some implementations, the wireless device 2000 may include multiple transmit antennas (each with a corresponding transmit chain) and multiple receive antennas (each with a corresponding receive chain). The modem 2030 may communicate bidirectionally with at least one AP (such as the first AP 110 or the second AP 120) via the antenna 2040. As described above, in some implementations, the modem may also communicate bidirectionally with other STAs directly via the antenna 2040 without using an intermediate AP.

[0196] The modem 2030 may include a digital processing circuit system, an automatic gain control (AGC), a demodulator, a decoder, and a demultiplexer. The digital signal received from the transceiver is provided to the digital signal processing circuit system, which is configured to capture the received signal, for example, by detecting the presence of the received signal and estimating the initial timing and frequency offset. The digital signal processing circuit system is further configured to digitally condition the digital signal to ultimately obtain a narrowband signal, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correction for I / O imbalance), and applying digital gain. The output of the digital signal processing circuit system is fed to the AGC, which is configured to determine the appropriate gain using information extracted from the digital signal, for example, in one or more received training fields. The output of the digital signal processing circuit system is also coupled to a demodulator, which is configured to extract modulated symbols from the signal and reversely map the symbols to points in the modulation constellation to provide demodulated bits. The demodulator is coupled to a decoder that is configured to decode the demodulated bits to provide decoded bits that are then fed to a demultiplexer for demultiplexing. The demultiplexed bits can then be provided to the processor 2010 for processing, evaluation, or interpretation, for example, by one or more host applications executing on the processor.

[0197] The wireless device 2000 may include a coordinated transmission control unit 2090. The coordinated transmission control unit 2090 may implement any coordinated transmission technology described in the present disclosure. For example, the coordinated transmission control unit 2090 may be configured to determine whether to use resource assignment based on RSSI measurements of a MAP-CT-Trigger message from a TXOP owner. In some implementations, the coordinated transmission control unit 2090 may be distributed within the processor 2010, the memory 2020, and the bus 2005. The memory 2020 may include computer instructions that can be executed by the processor 2010 to implement the functionality of the coordinated transmission control unit 2090. Any of these functionalities may be implemented partially (or completely) in hardware or on the processor 2010.

[0198] Figures 1-20 and the operations described herein are examples intended to aid in understanding example implementations and should not be used to limit potential implementations or to limit the scope of the claims. Some implementations may perform additional operations, perform fewer operations, perform operations in parallel or in a different order, and perform some operations differently.

[0199] As used herein, a phrase referring to "at least one" 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.

[0200] The various illustrative components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in conjunction with the 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 is illustrated 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.

[0201] The hardware and data processing apparatus for implementing the various illustrative components, logic, logic blocks, modules, and circuits described in conjunction with the aspects disclosed herein may be implemented or executed with a general purpose single-chip or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, specific processes, operations, and methods may be performed by circuit systems dedicated to a given function.

[0202] As described above, in some aspects, the realization of the subject matter described in this specification can be implemented as software.For example, each function of each component disclosed herein or each frame or step of the method, operation, process or algorithm disclosed herein can be implemented as one or more modules of one or more computer programs.Such computer programs may include non-transient processors or computer executable instructions encoded on one or more tangible processors or computer-readable storage media, which are used to be executed or control the operation of the data processing device by the data processing device including the components of the device described herein.As an example and not limitation, this storage medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, or any other medium that can be used to store program codes in the form of instructions or data structures.The above combination should also be included in the scope of storage media.

[0203] Various modifications to the implementations described in this disclosure may be apparent to those of ordinary skill in the art, and the universal principles defined herein may be applied to other implementations without departing from the spirit or scope of the disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but should be granted the widest scope consistent with the disclosure, the principles and novel features disclosed herein.

[0204] In addition, 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, while 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 removed from the combination, and a claimed combination may be directed to a subcombination, or a variation of a subcombination.

[0205] Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be understood as requiring such operations to be performed in the particular order shown or in a sequential order, or to perform all the 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 that are 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 illustrated operations. In some environments, multitasking and parallel processing may be advantageous. In addition, the separation of various system components in the implementation described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

Claims

1. A wireless communication device for use in a first station (STA) associated with a first access point (AP) of a first basic service set (BSS), comprising: at least one modem; at least one processor communicatively coupled to the at least one modem; as well as 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 in conjunction with the at least one modem, is configured to: receiving a message from the first AP indicating allocated resources for coordinated transmission during a portion of a transmission opportunity controlled by a second AP of a second BSS; as well as Data is transmitted from the first STA to the first AP as part of the coordinated transmission during the portion of the transmission opportunities concurrently with communications between a second AP and a second STA associated with the second AP.

2. The first STA as claimed in claim 1, wherein: The condition for preventing the use of the allocated resources is based at least in part on whether the transmit power of the first STA will cause interference above a threshold amount to communications between the second AP and a second STA associated with the second AP, and is based at least in part on an amount of interference that the second AP will tolerate as a result of the first STA using the allocated resources.

3. The first STA of claim 2, wherein the processor readable code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to: receiving coordinated uplink (CO-UL) parameters and an identifier of the second AP; and A Multi-AP Coordinated Transmission Trigger (MAP-CT-Trigger) message transmitted from the second AP is detected using the identifier of the second AP, wherein the MAP-CT-Trigger message indicates a start of the portion of the transmission opportunities.

4. The first STA of claim 3, wherein the processor readable code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to: A determination is made whether to use the allocated resources based at least in part on the CO-UL parameters.

5. The first STA of claim 3, wherein the processor readable code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to: measuring the signal strength of the MAP-CT-Trigger message; and An uplink power limit for the coordinated transmission from the first STA to the second AP is determined based at least in part on the signal strength and the CO-UL parameter.

6. The first STA of claim 5, wherein the processor readable code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to: Whether the condition is satisfied is determined based at least in part on the uplink power limit and a transmit power setting of the first STA.

7. A wireless communication device for use in a first access point (AP) of a first basic service set (BSS), comprising: at least one modem; at least one processor communicatively coupled to the at least one modem; as well as 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 in conjunction with the at least one modem, is configured to: transmitting a multi-AP coordinated transmission trigger (MAP-CT-Trigger) message to a plurality of APs to indicate the start of a portion of allocated resources and a transmission opportunity, wherein the allocated resources are allocated to one or more second APs of the plurality of APs for coordinated transmission on a wireless channel during the portion of the transmission opportunity; as well as As part of the coordinated transmission during the portion of the transmission opportunities, data is transmitted to or received from at least a first STA of the first BSS.

8. The wireless communication device of claim 7, wherein the processor readable code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to: Operating as a controller of the transmission opportunity based at least in part on determining that the first AP has won contention for the transmission opportunity.

9. The wireless communication device of claim 7, wherein the first AP is a master AP or other AP having a dedicated role as a controller of transmission opportunities including the transmission opportunity.

10. The wireless communication device of claim 7, wherein: The coordinated transmission includes concurrent uplink communications from the first STA to the first AP and from one or more second STAs to the one or more second APs, and The condition to which the one or more second APs or the one or more second STAs are subject is configured to prevent the one or more second STAs from using the allocated resources when the transmit power of the one or more second STAs is higher than a threshold.

11. The wireless communication device of claim 10, wherein the processor readable code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to: A coordinated uplink (CO-UL) parameter is included in a multi-AP scheduling trigger (MAP-Sch-Trigger) message, where the CO-UL parameter indicates the condition.

12. The wireless communication device of claim 11, wherein the CO-UL parameter is based at least in part on the transmit power of the first AP and an amount of interference that the first AP will tolerate.

13. The wireless communication device of claim 11, wherein: The MAP-Sch-Trigger message is configured to cause the one or more second APs to retransmit the CO-UL parameters to the one or more second STAs, and The CO-UL parameter can be used by each of the one or more second STAs to determine whether its transmit power will cause interference to the first AP above the threshold.

14. The wireless communication device of claim 7, wherein: The coordinated transmission includes concurrent downlink communications from the first AP to the first STA and from the one or more second APs to one or more second STAs, and The condition to which the one or more second APs or the one or more second STAs are subject is configured to prevent the one or more second APs from using the allocated resources when a transmit power of the one or more second APs is higher than a threshold.

15. The wireless communication device of claim 14, wherein the processor readable code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to: during the transmission opportunity: instructing the first STA to transmit a test communication for measuring a first received signal strength indicator (RSSI) between the first STA and the first AP, wherein the test communication is a null packet or a quality of service (QoS) packet; determining a coordinated downlink (CO-DL) parameter based at least in part on an estimated transmit power of the first AP for the coordinated transmission and an estimated channel quality between the first AP and the first STA, wherein the estimated channel quality is estimated based on the first RSSI; as well as The CO-DL parameters for the one or more second APs are included in a multi-AP scheduling trigger (MAP-Sch-Trigger) message or the MAP-CT-Trigger message.

16. A method performed by a first station (STA) associated with a first access point (AP) of a first basic service set (BSS), comprising: receiving a message from the first AP indicating allocated resources for coordinated transmission during a portion of a transmission opportunity controlled by a second AP of a second BSS; as well as Data is transmitted from the first STA to the first AP as part of the coordinated transmission during the portion of the transmission opportunities concurrently with communications between a second AP and a second STA associated with the first AP.

17. A method as claimed in claim 16, wherein the condition for preventing the use of the allocated resources is based at least in part on whether the transmit power of the first STA will cause interference higher than a threshold amount to communications between the second AP and a second STA associated with the second AP, and is based at least in part on the amount of interference that the second AP will tolerate as a result of the first STA using the allocated resources.

18. The method of claim 17, further comprising: receiving coordinated uplink (CO-UL) parameters and an identifier of the second AP; detecting a Multi-AP Coordinated Transmission Trigger (MAP-CT-Trigger) message transmitted from the second AP using the identifier of the second AP, wherein the MAP-CT-Trigger message indicates a start of the portion of the transmission opportunity; and A determination is made whether to use the allocated resources based at least in part on the CO-UL parameters.

19. The method of claim 17, further comprising, prior to the coordinated transmission: measuring the signal strength of the MAP-CT-Trigger message; and An uplink power limit for the coordinated transmission from the first STA to the first AP is determined based at least in part on the signal strength and the CO-UL parameter.

20. The method of claim 19, further comprising: Whether the condition is satisfied is determined based at least in part on the uplink power limit and a transmit power setting of the first STA.

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