Method and apparatus for coexistence via synchronous channel access

Abstract

The present disclosure provides methods, devices, and systems for synchronized channel access. Some implementations more specifically relate to facilitating coexistence between wireless communication devices that support synchronized channel access and wireless communication devices that do not support synchronized channel access. A group of access points may schedule periodically recurring synchronized channel access periods by periodically transmitting silence elements. The silence elements establish recurring silence periods during which legacy devices are not permitted to transmit. In some implementations, an access point may transmit one or more silence override elements, each of which is associated with a corresponding silence element and indicates to other access points that support synchronized channel access that they are permitted to contend for access during the corresponding silence period. In some other implementations of synchronized channel access, an access point that supports synchronized channel access that wins contention after one or more consecutive synchronized channel access periods during which no other synchronized access point wins contention may be eligible for an extended TXOP.

Description

[0001] Priority information

[0002] This patent application claims priority under 35 U.S.C. §119 to U.S. Provisional Patent Application No. 62 / 889,919, entitled “SYNCHRONIZED CHANNEL ACCESS COEXISTENCE,” filed on August 21, 2019, and U.S. Non-Provisional Patent Application No. 16 / 991,943, entitled “SYNCHRONIZED CHANNEL ACCESS COEXISTENCE,” filed on August 12, 2020, both of which are assigned to the assignee of this application and are expressly incorporated herein by reference. Technical Field

[0003] The present disclosure relates generally to wireless communications and, more particularly, to techniques for facilitating coexistence with wireless communication devices supporting access via synchronous channels.

[0004] Related technical description

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

[0006] In a typical WLAN deployment, wireless communication devices are free to contend for access to a wireless channel according to specific rules. Generally speaking, before a wireless communication device (such as an AP or STA) is allowed to transmit data, it must perform a clear channel assessment (CCA) and determine that the desired wireless channel is idle. For example, physical carrier sensing may involve measuring the received signal strength of an interfering frame, and then comparing this measurement to a threshold to determine whether the channel is busy. If the channel remains idle, the wireless communication device initiates a backoff timer, which indicates the duration of time the device must sense that the medium is idle before the device is allowed to transmit. If the channel remains idle until the backoff timer expires, the wireless communication device becomes the owner of the transmission opportunity (TXOP) and can begin transmitting.

[0007] Overview

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

[0009] One innovative aspect of the subject matter described in the present disclosure can be implemented in a method for wireless communication by wireless communication devices of a first access point (AP). The method includes exchanging wireless packets with at least a first group of wireless communication devices. The wireless packets include one or more silence elements, each silence element indicating to a second group of wireless communication devices that they are not permitted to transmit on a wireless channel during a silence period defined by the silence element. The wireless packets also include a silence override element indicating to the first group of wireless communication devices whether, for each of one or more of the silence elements, they are permitted to contend for access to the wireless channel during a contention period within the silence period defined by the corresponding silence element. The method further includes contending for access to the wireless channel during one or more of the contention periods indicated by the corresponding silence element and the silence override element.

[0010] Another innovative aspect of the subject matter described in this disclosure can be implemented in a wireless communication device of a first access point (AP). The wireless communication device includes at least one modem, at least one processor communicatively coupled to the at least one modem, and at least one memory communicatively coupled to the at least one processor and storing processor-readable code. The code, when executed by the at least one processor in conjunction with the at least one modem, is configured to cause the wireless communication device to exchange wireless packets with at least a first group of wireless communication devices. The wireless packets include one or more silence elements, each silence element indicating to the second group of wireless communication devices that they are not permitted to transmit on a wireless channel during a silence period defined by the silence element. The wireless packets also include a silence override element indicating to the first group of wireless communication devices whether, for each of one or more of the silence elements, they are permitted to contention for access to the wireless channel during a contention period within the silence period defined by the corresponding silence element. The code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to cause the wireless communication device to contention for access to the wireless channel during one or more of the contention periods indicated by the corresponding silence element and the silence override element.

[0011] In some implementations of the above methods and wireless communication devices, the silence override element is not interpretable by the second group of wireless communication devices. In some implementations of the above methods and wireless communication devices, the first group of wireless communication devices is not permitted to contend for access to the wireless channel during each silence period for a remainder following the corresponding contention period.

[0012] In some implementations of the above methods and wireless communication devices, each silence element includes a field indicating the periodicity of the corresponding silence period, a field indicating the duration of the corresponding silence period, and a field indicating the beginning of the corresponding silence period. In some implementations of the above methods and wireless communication devices, a silence override element includes a bitmap comprising a plurality of bits, each bit of the plurality of bits being associated with a corresponding silence element and indicating whether the first group of wireless communication devices is permitted to contend for access to the wireless channel during a contention period within the silence period defined by the corresponding silence element. In some implementations of the above methods and wireless communication devices, the silence override element indicates the duration of each contention period.

[0013] In some implementations of the above methods and wireless communication devices, the exchange of wireless packets includes transmitting or receiving a management frame that includes one or more silence elements and silence override elements. For example, the management frame may be a beacon frame. In some implementations of the above methods and wireless communication devices, the first AP may transmit an operation element indicating that the first AP supports the use of the silence override element. In some implementations of the above methods and wireless communication devices, the first AP may receive a capability element from a wireless communication device in the first group of wireless communication devices indicating that the wireless communication device supports the use of the silence override element.

[0014] In some implementations of the above methods and wireless communication devices, the first group of wireless communication devices includes one or more other APs, and the first AP is configured to synchronize a clock with a clock of each of the one or more other APs. In some implementations of the above methods and wireless communication devices, the first group of wireless communication devices does not include any stations.

[0015] In some implementations of the above methods and wireless communication devices, the first AP obtains a transmission opportunity (TXOP) on the wireless channel during a corresponding silent period based on winning contention in a corresponding contention period. The first AP can then exchange one or more wireless data packets on the wireless channel during the TXOP.

[0016] Another innovative aspect of the subject matter described in the present disclosure can be implemented in a method for wireless communication by a wireless communication device of a first access point (AP). The method includes exchanging wireless packets with at least a first group of wireless communication devices including the first AP. The wireless packets include channel access information indicating recurring channel access periods for a wireless channel, each channel access period including a contention period during which the first group of wireless communication devices is scheduled to contend for access to the wireless channel. The method also includes contending for access to the wireless channel during a plurality of contention periods associated with the plurality of corresponding channel access periods. The method also includes determining a number of consecutive channel access periods in the plurality of channel access periods during which no wireless communication device in the first group of wireless communication devices wins contention. The method also includes obtaining a transmission opportunity (TXOP) on the wireless channel during another channel access period in the plurality of channel access periods based on winning contention in the corresponding contention period, the TXOP having a length based on the number. The method also includes exchanging one or more wireless data packets on the wireless channel during the TXOP.

[0017] Another innovative aspect of the subject matter described in this disclosure can be implemented in a wireless communication device of a first AP. The wireless communication device includes at least one modem, at least one processor communicatively coupled to the at least one modem, and at least one memory communicatively coupled to the at least one processor and storing processor-readable code. The code, when executed by the at least one processor in conjunction with the at least one modem, is configured to cause the wireless communication device to exchange wireless packets with at least a first group of wireless communication devices comprising the first AP. The wireless packets include channel access information indicating recurring channel access periods for a wireless channel, each channel access period including a contention period during which the first group of wireless communication devices is scheduled to contend for access to the wireless channel. The code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to cause the wireless communication device to contend for access to the wireless channel during a plurality of contention periods associated with the plurality of corresponding channel access periods. The code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to cause the wireless communication device to determine a number of consecutive channel access periods in the plurality of channel access periods during which no wireless communication device in the first group won a contention. The code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to cause the wireless communication device to obtain a transmission opportunity (TXOP) on the wireless channel during another channel access period of the plurality of channel access periods based on winning contention in the corresponding contention period, the TXOP having a length based on the quantity. The code, when executed by the at least one processor in conjunction with the at least one modem, is further configured to cause the wireless communication device to exchange one or more wireless packets on the wireless channel during the TXOP.

[0018] In some implementations of the above methods and wireless communication devices, the first group of wireless communication devices is not permitted to contend for access to the wireless channel during a remainder of each channel access period after a corresponding contention period.

[0019] In some implementations of the above methods and wireless communication devices, the exchange of wireless packets includes transmitting or receiving a management frame that includes channel access information. For example, the management frame may be a beacon frame. In some implementations of the above methods and wireless communication devices, the channel access information indicates the periodicity of a recurring channel access period, the duration of a recurring channel access period, the start of a next channel access period, and the duration of a contention period.

[0020] In some implementations of the above methods and wireless communication devices, the first AP may transmit an operations element indicating that the first AP supports the use of a channel access period. In some implementations of the above methods and wireless communication devices, the first AP may receive a capabilities element from a wireless communication device in the first group of wireless communication devices indicating that the wireless communication device supports the use of a channel access period.

[0021] In some implementations of the above methods and wireless communication devices, the first group of wireless communication devices includes one or more other APs, and the first AP is configured to synchronize a clock with a clock of each of the one or more other APs. In some implementations of the above methods and wireless communication devices, the first group of wireless communication devices does not include any stations. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. It should be noted that the relative dimensions of the following figures may not be drawn to scale.

[0024] Figure 1 A schematic diagram illustrating an example wireless communication network is shown.

[0025] Figure 2A An example protocol data unit (PDU) that can be used for communication between an access point (AP) and a number of stations (STAs) is shown.

[0026] Figure 2B Show Figure 2A Example fields in the PDU.

[0027] Figure 3 Another example PDU that can be used for communication between an AP and several STAs is shown.

[0028] Figure 4 A block diagram of an example wireless communication device is shown.

[0029] Figure 5AA block diagram of an example access point (AP) is shown.

[0030] Figure 5B A block diagram of an example station (STA) is shown.

[0031] Figure 6A An example synchronized channel access period is shown.

[0032] Figure 6B An example synchronized channel access period is shown during which there are interfering transmissions from other wireless communication devices.

[0033] Figure 7 An example recurring silent period is shown.

[0034] Figure 8 Example silence elements that may be used to signal corresponding silence periods are shown.

[0035] Figure 9 Synchronized channel access techniques according to some implementations are shown.

[0036] Figure 10 A flowchart illustrating an example process for synchronized channel access according to some implementations is shown.

[0037] Figure 11 An example silence override element is shown that may be used to signal an override of a corresponding silence period.

[0038] Figure 12 A flow chart illustrating a process for exchanging one or more wireless data packets is shown.

[0039] Figure 13 A block diagram of an example wireless communication device is shown in accordance with some implementations.

[0040] Figure 14 A flow chart illustrating another example process for synchronized channel access according to some implementations is shown.

[0041] Figure 15 Synchronized channel access techniques according to some implementations are shown.

[0042] Figure 16 A block diagram of an example wireless communication device is shown in accordance with some implementations.

[0043] Like reference numbers and designations in the various drawings indicate like elements.

[0044] Detailed description

[0045] The following description is directed to certain specific implementations for the purpose of describing the innovative aspects of the present disclosure. However, one of ordinary skill in the art will readily recognize that the teachings herein can be applied in many different ways. The described implementations can be implemented in a manner that is capable of being 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 any other standard defined by the IEEE. The described implementations may be implemented in any device, system, or network capable of transmitting and receiving radio frequency (RF) signals in accordance with one or more of the Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards promulgated by the Third Generation Partnership Project (3GPP). The described implementations may be implemented in any device, system, or network capable of transmitting and receiving RF signals in accordance with one or more of the following technologies or techniques: code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), single-user (SU) multiple-input multiple-output (MIMO), and multi-user (MU) MIMO. The described implementations may also be implemented using other wireless communication protocols or RF signals suitable for use in one or more of a wireless personal area network (WPAN), a wireless local area network (WLAN), a wireless wide area network (WWAN), or an Internet of Things (IoT) network.

[0046] Various implementations generally relate to synchronized channel access techniques. Some implementations more specifically relate to techniques for facilitating coexistence between wireless communication devices that support synchronized channel access and wireless communication devices that do not support synchronized channel access. Each synchronized channel access period may include a scheduled contention period during which multiple synchronized APs contend for access, followed by a communication period during which the successful AP holds the TXOP. In some implementations, synchronized APs may schedule periodically recurring synchronized channel access periods by periodically transmitting quiet elements. The quiet elements establish recurring quiet periods during which legacy devices are not permitted to transmit. For example, one or more synchronized APs may transmit a management frame (e.g., a beacon frame or a probe response frame) that includes one or more quiet elements specifying corresponding quiet periods. In some implementations, the management frame containing the quiet elements may further include one or more quiet override elements, each associated with a corresponding quiet element. The quiet override elements indicate to the synchronized APs that the quiet period established by the corresponding quiet element will be used for synchronized channel access and, therefore, that the synchronized APs are permitted to contend for access during the corresponding contention period.

[0047] In some implementations of synchronized channel access described herein, a synchronized AP that wins contention after one or more consecutive contention periods during which no synchronized AP wins contention may be eligible for an extended TXOP. In some such implementations, the length of the extended TXOP may be based on the number (quantity) of consecutive contention periods during which no synchronized AP wins contention. For example, the length of the extended TXOP may be an integer multiple of the normal maximum duration of the TXOP, where the value of the integer is equal to the number of consecutive contention periods determined to have been missed (i.e., contention periods during which no synchronized AP wins contention).

[0048] Specific implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages. In some implementations, the described techniques may be used to facilitate coexistence between wireless communication devices configured for access via synchronized channels and wireless communication devices that are not configured for access via synchronized channels. Some implementations ensure that wireless communication devices that support access via synchronized channels are provided with sufficient access to the wireless medium to, for example, meet their throughput and latency requirements. For example, some implementations enable efficient use of the wireless medium by reserving a wireless channel for use by the AP to transmit downlink communications to associated STAs and to schedule uplink communication transmissions from associated STAs during a synchronized channel access period. As another example, some implementations enable efficient use of the wireless channel by granting a wireless communication device configured for access via synchronized channels an extended time duration for communicating with an associated station (STA).

[0049] Figure 1 A block diagram of an example wireless communication network 100 is shown. According to some aspects, the wireless communication network 100 may be an example of a wireless local area network (WLAN), such as a Wi-Fi network (and will be referred to as WLAN 100 hereinafter). For example, the WLAN 100 may be a network that implements at least one of the IEEE 802.11 family of 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 multiple APs 102.

[0050] 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, among other possibilities. STA 104 may represent a variety of devices, such as a mobile phone, a personal digital assistant (PDA), other handheld devices, a netbook, a netbook computer, a tablet computer, a laptop device, a display device (e.g., a TV, a computer monitor, a navigation system, etc.), a music or other audio or stereo device, a remote control device ("remote control"), a printer, a kitchen or other home appliance, a key fob (e.g., for a passive keyless entry and start (PKES) system), and other possibilities.

[0051] A single AP 102 and the associated set of STAs 104 may be referred to as a basic service set (BSS), which is managed by the corresponding AP 102 . Figure 1 Additionally shown is an example coverage area 106 of the AP 102, which may represent a basic service area (BSA) of the WLAN 100. A BSS may be identified to users by a service set identifier (SSID) and may also be identified to other devices by a basic service set identifier (BSSID), which may be the media access control (MAC) address of the AP 102. The AP 102 periodically broadcasts a beacon frame ("beacon") including the BSSID to enable any STA 104 within 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.

[0052] 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, 2.4 GHz, 5 GHz, 6 GHz, or 60 GHz bands). To perform a passive scan, a STA 104 listens for beacons transmitted by a 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, a STA 104 generates probe requests and sequentially transmits these probe requests on each channel to be scanned, and listens for probe responses from the AP 102. Each STA 104 may be configured to identify or select an AP 102 with which to associate based on scan information obtained through passive or active scanning, and to perform authentication and association operations to establish a communication link 108 with the selected AP 102. The AP 102 assigns an association identifier (AID) to the STA 104 at the end of the association operation, and the AP 102 uses the AID to track the STA 104.

[0053] As wireless networks become increasingly common, a STA 104 may have the opportunity to select one of many B16s within range of the STA or multiple APs 102 that together form an extended service set (ESS) (including multiple connected B16s). Extended network stations associated with a WLAN 100 may be connected to a wired or wireless distribution system that allows multiple APs 102 to be connected in such an ESS. In this way, a STA 104 may be covered by more than one AP 102 and may associate with different APs 102 at different times for different transmissions. In addition, after associating with an AP 102, the 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 with more suitable network characteristics (such as a greater received signal strength indicator (RSSI) or reduced traffic load).

[0054] In some cases, STAs 104 may form a network without APs 102 or other equipment other than the STAs 104 themselves. One example of such a network is an ad hoc network (or wireless ad hoc network). An ad hoc network may alternatively be referred to as a mesh network or a peer-to-peer (P2P) network. In some cases, an ad hoc network may be implemented within a larger wireless network, such as WLAN 100. In such an implementation, while STAs 104 may be able to communicate with each other via APs 102 using communication links 108, STAs 104 may also communicate directly with each other via direct wireless links 110. In addition, two STAs 104 may communicate via direct communication links 110 regardless of whether they are associated with and served by the same AP 102. In such an ad hoc system, one or more STAs 104 may assume the role played by APs 102 in a BSS. Such STAs 104 may be referred to as group owners (GOs) and may coordinate transmissions within the ad hoc network. Examples of direct 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.

[0055] The AP 102 and the STA 104 can 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 amendments, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be. These standards define WLAN radio and baseband protocols for the PHY and 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 and from each other in the form of physical layer convergence protocol (PLCP) protocol data units (PPDUs). The AP 102 and STA 104 in the WLAN 100 can transmit PPDUs on an unlicensed spectrum, which can be a portion of the spectrum that includes frequency bands traditionally used by Wi-Fi technology, such as the 2.4 GHz band, the 5 GHz band, the 60 GHz band, the 3.6 GHz band, and the 900 MHz band. Some implementations of the AP 102 and STA 104 described herein can also communicate in other frequency bands, such as the 6 GHz band, that can support both licensed and unlicensed communications. The AP 102 and STA 104 can also be configured to communicate in other frequency bands, such as shared licensed bands, where multiple operators may have licenses to operate in one or more of the same or overlapping frequency bands.

[0056] Each frequency band can include multiple sub-bands or frequency channels. For example, PPDUs compliant with the IEEE 802.11n, 802.11ac, and 802.11ax standard amendments can be transmitted in the 2.4 GHz and 5 GHz frequency bands, where each frequency band is divided into multiple 20 MHz channels. Thus, these PPDUs are transmitted on physical channels with a minimum bandwidth of 20 MHz, but larger channels can be formed through channel bonding. For example, a PPDU can be 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.

[0057] Each PPDU is a composite structure that includes a PHY preamble and a payload in the form of a PLCP service data unit (PSDU). The information provided in the preamble can be used by the receiving device to decode subsequent data in the PSDU. In instances where the PPDU is transmitted over a bonded channel, the preamble field can be replicated and transmitted in each of the multiple component channels. The PHY preamble may include both a legacy portion (or "legacy preamble") and a non-legacy portion (or "non-legacy preamble"). The legacy preamble can be used for packet detection, automatic gain control, and channel estimation, among other purposes. The legacy preamble can also generally be used to maintain compatibility with legacy devices. The format, encoding, and information provided therein of the non-legacy portion of the preamble are based on the specific IEEE 802.11 protocol to be used to transmit the payload.

[0058] Figure 2A An example protocol data unit (PDU) 200 is shown that can be used for wireless communication between an AP and a number of STAs. For example, PDU 200 can be configured as a PPDU. As shown, PDU 200 includes a PHY preamble 202 and a PHY payload 204. For example, preamble 202 can include a legacy portion, which itself includes a legacy short training field (L-STF) 206, which can be composed of two BPSK symbols, a legacy long training field (L-LTF) 208, which can be composed of two BPSK symbols, and a legacy signal field (L-SIG) 210, which can be composed of two BPSK symbols. The legacy portion of preamble 202 can be configured according to the IEEE 802.11a wireless communication protocol standard. The preamble 202 may also include a non-legacy portion including, for example, one or more non-legacy fields 212 that comply with an IEEE wireless communication protocol, such as IEEE 802.11ac, 802.11ax, 802.11be, or a later wireless communication standard.

[0059] The L-STF 206 generally enables the receiving device to perform automatic gain control (AGC) and coarse timing and frequency estimation. The L-LTF 208 generally enables the receiving device to perform fine timing and frequency estimation, and can also perform an initial estimate of the wireless channel. The L-SIG 210 generally enables the receiving device to determine the duration of the PDU and use the determined duration to avoid transmitting over the PDU. For example, the L-STF 206, L-LTF 208, and L-SIG 210 can be modulated according to a binary phase shift keying (BPSK) modulation scheme. The payload 204 can be modulated according to a BPSK modulation scheme, a quadrature BPSK (Q-BPSK) modulation scheme, a quadrature amplitude modulation (QAM) modulation scheme, or another appropriate modulation scheme. The payload 204 may include a PSDU including a data field (DATA) 214, which in turn may carry higher layer data, such as in the form of a media access control (MAC) protocol data unit (MPDU) or an aggregated MPDU (A-MPDU).

[0060] Figure 2B Shown Figure 2A 2. Example L-SIG 210 in PDU 200. L-SIG 210 includes a data rate field 222, reserved bits 224, a length field 226, parity bits 228, and a tail field 230. Data rate field 222 indicates the data rate (note that the data rate indicated in data rate field 212 may not be the actual data rate of the data carried in payload 204). Length field 226 indicates the packet length, for example, in symbols or bytes. Parity bits 228 can be used to detect bit errors. Tail field 230 includes tail bits, which can be used by a receiving device to terminate the operation of a decoder (e.g., a Viterbi decoder). The receiving device can use the data rate and length indicated in data rate field 222 and length field 226 to determine the packet duration, for example, in microseconds (μs) or other time units.

[0061] Figure 3Another example PDU 350 is shown that can be used for wireless communication between an AP and several STAs. PDU 350 can be used for MU-OFDMA or MU-MIMO transmission. PDU 350 includes a PHY preamble, which includes a legacy portion 352 and a non-legacy portion 354. PDU 350 may further include a PHY payload 356 following the preamble (e.g., in the form of a PSDU including a data field 374). Legacy portion 352 includes L-STF 358, L-LTF 360, and L-SIG 362. According to the IEEE 802.11ax amendment to the IEEE 802.11 wireless communication protocol standard, non-legacy portion 354 of the preamble and data field 374 may be formatted as a high-efficiency (HE) WLAN preamble and frame, respectively. The non-legacy portion 354 includes a repeated legacy signal field (RL-SIG) 364, a first HE signal field (HE-SIG-A) 366, a second HE signal field (HE-SIG-B) 368 encoded separately from the HE-SIG-A 366, a HE short training field (HE-STF) 370, and several HE long training fields (HE-LTF) 372. As with the L-STF 358, L-LTF 360, and L-SIG 362, in instances involving the use of bonded channels, the information in the RL-SIG 364 and HE-SIG-A 366 may be replicated and transmitted in each component 20 MHz channel. In contrast, the HE-SIG-B 368 may be unique to each 20 MHz channel and may be specific to a particular STA 104.

[0062] The RL-SIG 364 may indicate to the HE-compatible STAs 104 that the PPDU is a HE PPDU. The AP 102 may use the HE-SIG-A 366 to identify multiple STAs 104 and inform them that the AP has scheduled UL or DL ​​resources for them. The HE-SIG-A 366 may be decoded by each HE-compatible STA 104 served by the AP 102. The HE-SIG-A 366 includes information that may be used by each identified STA 104 to decode the associated HE-SIG-B 368. For example, the HE-SIG-A 366 may indicate the frame format (including the location and length of the HE-SIG-B 368), available channel bandwidth, modulation and coding scheme (MCS), and other possibilities. The HE-SIG-A 366 may also include HE WLAN signaling information that may be used by STAs 104 other than the identified STAs 104.

[0063] The HE-SIG-B 368 may carry STA-specific scheduling information, such as, for example, per-user MCS values ​​and per-user RU allocation information. In the context of DL MU-OFDMA, such information enables the corresponding STA 104 to identify and decode the corresponding RU in the associated data field. Each HE-SIG-B 368 includes a common field and at least one STA-specific ("user-specific") field. The common field may indicate the RU distribution for multiple STAs 104, indicate the RU assignment in the frequency domain, indicate which RUs are allocated for MU-MIMO transmission and which RUs correspond to MU-OFDMA transmission, and the number of users in the allocation, etc. The common field may be encoded with common bits, CRC bits, and tail bits. The user-specific fields are assigned to a specific STA 104 and may be used to schedule specific RUs and indicate the schedule to other WLAN devices. Each user-specific field may include multiple user block fields (which may be followed by padding). Each user block field may include two user fields containing information for two respective STAs to decode their respective RU payloads in the data field 374 .

[0064] As described above, the AP 102 and the STAs 104 may support multi-user (MU) communications; that is, concurrent transmissions from one device to each of multiple devices (e.g., multiple simultaneous downlink (DL) communications from the AP 102 to the corresponding STAs 104), or concurrent transmissions from multiple devices to a single device (e.g., multiple simultaneous uplink (UL) transmissions from the corresponding STAs 104 to the AP 102). To support MU transmissions, the AP 102 and the STAs 104 may utilize multi-user multiple-input multiple-output (MU-MIMO) and multi-user orthogonal frequency division multiple access (MU-OFDMA) techniques.

[0065] In the MU-OFDMA scheme, the available spectrum of a wireless channel can be divided into multiple resource units (RUs), each of which includes a number of different frequency subcarriers ("tones"). Different RUs can be allocated or assigned by the AP 102 to different STAs 104 at a specific time. The size and distribution of the RUs can be referred to as RU allocation. In some implementations, RUs can be allocated in 2 MHz intervals, and as such, the smallest RU can include 26 tones consisting of 24 data tones and 2 pilot tones. Therefore, in a 20 MHz channel, up to 9 RUs (such as a 26-tone RU at 2 MHz) can be allocated (because some tones are reserved for other purposes). Similarly, in a 160 MHz channel, up to 74 RUs can be allocated. Larger 52-tone, 106-tone, 242-tone, 484-tone, and 996-tone RUs can also be allocated. Adjacent RUs can be separated by empty subcarriers (such as a DC subcarrier), for example, to reduce interference between adjacent RUs, reduce receiver DC offset, and avoid transmit center frequency leakage.

[0066] For UL MU transmissions, the AP 102 may transmit a trigger frame to initiate and synchronize UL MU-OFDMA or UL MU-MIMO transmissions from multiple STAs 104 to the AP 102. Such a trigger frame may thereby enable multiple STAs 104 to send UL traffic concurrently in time to the AP 102. The trigger frame may address one or more STAs 104 by corresponding association identifiers (AIDs) and may assign one or more RUs to each AID (and thus each STA 104) that may be used to transmit UL traffic to the AP 102. The AP may also specify one or more random access (RA) RUs that unscheduled STAs 104 may contend for.

[0067] Figure 4 4 shows a block diagram of an example wireless communication device 400. In some implementations, the wireless communication device 400 may be a STA (such as the one described above with reference to FIG. Figure 1 In some implementations, the wireless communication device 400 may be an example of a device for an AP (such as one of the STAs 104 described above). Figure 1The wireless communication device 400 is an example of a device in the described AP 102. The wireless communication device 400 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 the 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).

[0068] The wireless communication device 400 may be or may include a chip, system on chip (SoC), chipset, package, or device that includes one or more modems 402 (e.g., Wi-Fi (IEEE 802.11 compliant) modems). In some implementations, the one or more modems 402 (collectively, “modems 402”) additionally include a WWAN modem (e.g., a 3GPP 4G LTE or 5G compatible modem). In some implementations, the wireless communication device 400 also includes one or more radios 404 (collectively, “radios 404”). In some implementations, the wireless communication device 406 further includes one or more processors, processing blocks, or processing elements 406 (collectively, “processors 406”) and one or more memory blocks or elements 408 (collectively, “memory 408”).

[0069] The modem 402 may include an intelligent hardware block or device (e.g., such as an application specific integrated circuit (ASIC)). The modem 402 is generally configured to implement the PHY layer. For example, the modem 402 is configured to modulate packets and output the modulated packets to the radio 404 for transmission on the wireless medium. Similarly, the modem 402 is configured to obtain modulated packets received by the radio 404 and demodulate these packets to provide demodulated packets. In addition to the modulator and demodulator, the modem 402 may further include digital signal processing (DSP) circuitry, automatic gain control (AGC), an encoder, a decoder, a multiplexer, and a demultiplexer. For example, when in transmit mode, data obtained from the processor 406 is provided to an encoder, which encodes the data to provide coded bits. The coded bits are then mapped to points in the modulation constellation (using the selected MCS) to provide modulated symbols. The modulated symbols may then be mapped to a number (N SS ) spatial streams or several (N STS) space-time streams. The modulated symbols in the corresponding spatial streams or space-time streams can 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 can then be provided to a digital-to-analog converter (DAC). The resulting analog signal can then be provided to an upconverter and ultimately to the radio 404. In implementations involving beamforming, the modulated symbols in the corresponding spatial streams are precoded via a steering matrix before being provided to the IFFT block.

[0070] When in receive mode, a digital signal received from radio 404 is provided to a DSP circuitry configured to acquire the received signal, for example, by detecting the presence of a signal and estimating initial timing and frequency offset. The DSP circuitry is further configured to digitally condition the digital signal, for example, using channel (narrowband) filtering, analog impairment adjustment (such as correcting I / Q imbalance), and applying digital gain to ultimately obtain a narrowband signal. The output of the DSP circuitry can then be fed to an AGC, which is configured to use information extracted from the digital signal (e.g., in one or more received training fields) to determine an appropriate gain. The output of the DSP circuitry 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 can be configured to process the LLRs to provide decoded bits. The decoded bits from all spatial streams are then fed to a demultiplexer for demultiplexing. The demultiplexed bits may then be descrambled and provided to the MAC layer (processor 406) for processing, evaluation, or interpretation.

[0071] The radio 404 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 circuitry, including at least one power amplifier (PA) and at least one low noise amplifier (LNA), respectively. The RF transmitter and receiver may, in turn, be coupled to one or more antennas. For example, in some implementations, the wireless communication device 400 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 symbols output from the modem 402 are provided to the radio 404, which then transmits these symbols via the coupled antennas. Similarly, the symbols received via the antennas are obtained by the radio 404, which then provides these symbols to the modem 402.

[0072] The processor 406 may comprise an intelligent hardware block or device designed to perform the functions described herein, 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 406 processes information received via the radio 404 and the modem 402, and processes information to be output by the modem 402 and the radio 404 for transmission over the wireless medium. For example, the processor 406 may implement the control plane and MAC layer, which are configured to perform various operations related to the generation and transmission of MPDUs, frames, or packets. The MAC layer is configured to perform or facilitate frame encoding and decoding, spatial multiplexing, space-time block coding (STBC), beamforming, and OFDMA resource allocation, among other operations or techniques. In some implementations, the processor 406 may generally control the modem 402 to cause the modem to perform the various operations described above.

[0073] The memory 404 may include tangible storage media such as random access memory (RAM) or read-only memory (ROM), or a combination thereof. The memory 404 may also store non-transitory processor or computer-executable software (SW) code containing instructions that, when executed by the processor 406, cause the processor to perform various operations for wireless communication described herein, including the 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.

[0074] Figure 5A A block diagram of an example AP 502 is shown. For example, the AP 502 may be a reference Figure 1 An example implementation of the AP 102 is described. The AP 502 includes a wireless communication device (WCD) 510 (although the AP 502 itself may also be generally referred to as a wireless communication device as used herein). For example, the wireless communication device 510 may be a wireless communication device (WCD) 510. Figure 41. An example implementation of the wireless communication device 4000 is described. AP 502 also includes multiple antennas 520 coupled to the wireless communication device 510 for transmitting and receiving wireless communications. In some implementations, AP 502 additionally includes an application processor 530 coupled to the wireless communication device 510, and a memory 540 coupled to the application processor 530. AP 502 further includes at least one external network interface 550 that enables AP 502 to communicate with a core network or backhaul network to gain access to an external network, including the Internet. For example, the external network interface 550 may include one or both of a wired (e.g., Ethernet) network interface and a wireless network interface (such as a WWAN interface). Components of the aforementioned components may communicate with other components of these components directly or indirectly over at least one bus. AP 502 further includes a housing that surrounds the wireless communication device 510, the application processor 530, the memory 540, and at least a portion of the antennas 520 and the external network interface 550.

[0075] Figure 5B A block diagram of an example STA 504 is shown. For example, STA 504 may be a reference Figure 1 104. The STA 504 includes a wireless communication device 515 (although the STA 504 itself may also be generally referred to as a wireless communication device as used herein). For example, the wireless communication device 515 may be a reference to Figure 4 1. Example implementation of the wireless communication device 400 described. STA 504 also includes one or more antennas 525 coupled to the wireless communication device 515 for transmitting and receiving wireless communications. STA 504 additionally includes an application processor 535 coupled to the wireless communication device 515, and a memory 545 coupled to the application processor 535. In some implementations, STA 504 further includes a user interface (UI) 555 (such as a touch screen or keyboard) and a display 565, which can be integrated with the UI 555 to form a touch screen display. In some implementations, STA 504 can further include one or more sensors 575 (such as one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors, for example). Components of the aforementioned components can communicate directly or indirectly with other components of these components over at least one bus. STA 504 further includes a housing that surrounds the wireless communication device 515, the application processor 535, the memory 545, and at least a portion of the antenna 525, the UI 555, and the display 565.

[0076] Access to the shared wireless medium is typically governed by a distributed coordination function (DCF). With DCF, there is no centralized master device that allocates the time and frequency resources of the shared wireless medium. Instead, before a wireless communication device (such as AP 102 or STA 104) is allowed to transmit data, the wireless communication device must wait for a specific time and then contend for access to the wireless medium. In some implementations, the wireless communication device can be configured to implement DCF by using carrier sense multiple access (CSMA) with collision avoidance (CA) (CSMA / CA) and timing intervals. Before transmitting data, the wireless communication device must perform a clear channel assessment (CCA) and determine whether the appropriate wireless channel is idle. CCA includes physical (PHY-level) carrier sensing and virtual (MAC-level) carrier sensing. Physical carrier sensing is accomplished by measuring the received signal strength of a valid frame, which is then compared to a threshold to determine whether the channel is busy. For example, if the received signal strength of a properly decoded preamble is above a threshold, the medium is considered busy. Physical carrier sensing also includes energy detection. Energy detection involves measuring the total energy received by the wireless communication device, regardless of whether the received signal represents a valid frame. If the total energy detected is above a threshold, the medium is considered busy. Virtual carrier sensing is accomplished using a Network Allocation Vector (NAV), which is an indicator of when the medium may next become idle. The NAV is reset each time a valid frame not addressed to the wireless communication device is received. The NAV effectively serves as a duration of time that must elapse before the wireless communication device can contend for access, even in the absence of a detected preamble or even if the detected energy is below a relevant threshold.

[0077] When the NAV reaches 0, the wireless communication device performs physical carrier sensing. If the channel remains idle for the appropriate interframe space (IFS), the wireless communication device initiates a backoff timer, which represents the duration of time the device must sense the medium as idle before the device is allowed to transmit. The backoff timer decrements by one slot each time the medium is sensed as idle during the corresponding slot interval. If the channel remains idle until the backoff timer expires, the wireless communication device becomes the owner (or owner) of a transmission opportunity (TXOP) and can begin transmitting. A TXOP is the duration of time the wireless communication device can transmit frames on a channel after it has won contention for the wireless medium. On the other hand, if one or more carrier sensing mechanisms indicate that the channel is busy, the MAC controller within the wireless communication device will not permit transmission.

[0078] Some APs and STAs can be configured to implement spatial reuse technology. For example, APs and STAs configured to communicate using IEEE802.11ax or 802.11be can be configured with BSS colors. APs associated with different BSSs can be associated with different BSS colors. If an AP or STA detects a wireless packet from another wireless communication device while contending for access, the AP or STA may apply different contention parameters based on whether the wireless packet is transmitted by or to another wireless communication device within its BSS, or is transmitted from a wireless communication device from an overlapping BSS (OBSS) (as determined by the BSS color indication in the preamble of the wireless packet). For example, if the BSS color associated with the wireless packet is the same as the BSS color of the AP or STA, the AP or STA can use the first received signal strength indication (RSSI) detection threshold when performing CCA on the wireless channel. However, if the BSS color associated with the wireless packet is different from the BSS color of the AP or STA, the AP or STA may use a second RSSI detection threshold value, which is greater than the first RSSI detection threshold value, instead of the first RSSI detection threshold value when performing CCA on the wireless channel. In this way, the requirement to win contention is relaxed when the interfering transmission is associated with the OBSS.

[0079] Recent wireless communication protocols, including IEEE 802.11be, may support scheduled access techniques as a supplement to or alternative to conventional DCF techniques, enabling multiple APs and STAs to share and communicate on a wireless medium. For example, multiple APs may be configured to support synchronized channel access techniques (such APs are hereinafter referred to as "synchronized APs"), which include using recurring channel access periods (hereinafter referred to as "synchronized channel access periods") during which the multiple synchronized APs are scheduled to contend for access to one or more wireless channels of a shared frequency band.

[0080] Figure 6A An example synchronized channel access period 602 is shown (eg, comprising a first channel access period 6021, a second channel access period 6022, and a third channel access period 6023). The channel access period 602 is based on a time interval τ. 接入 Each channel access period 602 includes a time duration τ at the beginning of the channel access period. 争用 Each channel access period 602 may also include a channel access period having a duration τ 通信602. Only during the contention period 604 at the beginning of the scheduled channel access period 602 does an AP that enables synchronized channel access and desires to communicate on the wireless channel contend for access. In addition, a STA that supports synchronized channel access may also understand the channel access information and remain silent during the channel access period 602 unless triggered by its associated AP.

[0081] The winner of the contention during the contention period 604 becomes the owner of a TXOP 606 (e.g., one of TXOPs 6061, 6062, and 6063), which may extend from the beginning of the corresponding communication period to the end of the communication period. However, the owner of the TXOP may not need the entire communication period. For example, in the second channel access period 6022, the TXOP 6062 does not extend to the end of the corresponding communication period. In some implementations, the synchronized AP is not permitted to contend for access to the wireless channel for the remainder of the corresponding channel access period after the contention period, even if the TXOP owner has completed transmission and reception. However, in some implementations, there may be a TXOP with a duration of τ between adjacent channel access periods 602. 开放 A time period (hereinafter also referred to as an "open period") during which the wireless medium is open for conventional contention-based access as governed by, for example, the above-mentioned CSMA / CA technique.

[0082] Figure 6B An example synchronized channel access period 602 is shown during which there are interfering transmissions from other wireless communication devices. For example, multiple synchronized APs may contend for access during a first contention period 6041 of a first channel access period 6021 beginning at time t1. One of the synchronized APs wins the contention and obtains a first TXOP 6061 beginning at time t2 and extending to time t3. During the first TXOP 6061, the AP may transmit or trigger the transmission of DL communications to one or more STAs, and receive UL communications from one or more STAs.

[0083] At time t4, during an open period between the end of the first TXOP 6061 of the first channel access period 6021 and the beginning of the contention period 6042 of the second channel access period 6022, another wireless communication device (e.g., an AP or STA not configured for access via the synchronized channel) contends for access to the wireless medium and obtains a TXOP 6081 that extends through the second contention period 6042. Thus, when the synchronized APs contend for access during the second contention period 6042 starting at time t5, they will detect that the wireless channel is busy (or "not idle" or "not clear") and none of them will obtain a TXOP during a subsequent communication period of the second channel access period 6022. Similarly, at time t6, during a communication period of the second channel access period 6022 that should have been used for a TXOP by one of the synchronized APs, another wireless communication device (e.g., an AP or STA not configured for access via the synchronized channel) contends for access to the wireless medium and obtains a TXOP 6082 that extends through the third contention period 6043. Thus, when the synchronized APs contend for access during the third contention period 6043 starting at time t7, they will detect that the wireless channel is not idle and none of them will obtain a TXOP during a subsequent communication period of the third channel access period 6023. In this way, the synchronized APs and their associated STAs may be unable to obtain access to the shared wireless medium due to other APs or STAs that are not configured for synchronized channel access.

[0084] Some wireless communication protocols, including those supporting the IEEE 802.11 standard, support the use of silent periods. Each silent period refers to a duration of time during which no wireless communication devices (including APs and STAs) are generally permitted to access one or more designated wireless channels of a shared frequency band. One initial motivation for supporting silent periods is to allow APs to perform measurements without interference, such as those required for dynamic frequency selection (DFS). In some implementations, silent periods can recur, for example, based on a given beacon interval. Furthermore, more than one silent period can be defined for each beacon interval.

[0085] Figure 7 Example recurring silent periods 704 and 706 are shown. In the illustrated example, recurring silent periods 704 and 706 (also referred to herein as "silent intervals" or "silent times") are arranged according to a time interval τ TBTT The target beacon transmission time (TBTT) is used to reproduce the Figure 7 In the example of FIG, the first set of recurring silent periods 704 (including silent periods 7041, 7042, and 7043) each has a duration τ QP1 , and the second set of recurring silent periods 706 (including silent periods 7061, 7062 and 7063) each has a duration τ QP2The silent period may be signaled, for example, by an AP in a BSS or a STA in a mesh BSS (MBSS) in a beacon, probe response, or other management frame. For example, the first and second sets of silent periods 704 and 706 may be signaled in beacon 702 (including beacons 7021, 7022, and 7023) transmitted at the TBTT.

[0086] Figure 8 An example silence element 800 is shown that can be used to signal a corresponding silent period. The silence element 800 can be transmitted to signal a silent period in a designated wireless channel or multiple (or even all) wireless channels of a shared frequency band. As described above, an AP or STA can include a silence element, such as silence element 800, in management frames including beacon frames and probe response frames. In the illustrated example, silence element 800 includes multiple fields, including an element ID 802, a length 804, a silence count 806, a silent period 808, a silent duration 810, and a silent offset 812. Element ID 802 can be a unique identifier for silence element 800. Length 804 can indicate the length of silence element 800. Silence count 806 can indicate the number of TBTTs remaining in the beacon interval until the next corresponding silent period begins. Silent period 808 can similarly indicate the number of beacon intervals until the next corresponding silent period begins. The silence duration 810 may indicate the duration of the corresponding silence period in, for example, TUs. The silence offset 812 may indicate the offset between the beginning of the corresponding silence period and the TBTT indicated by the silence count 806 in, for example, TUs.

[0087] Various implementations generally relate to synchronized channel access techniques. Some implementations more specifically relate to techniques for facilitating coexistence between wireless communication devices that support synchronized channel access and wireless communication devices that do not support synchronized channel access. Each synchronized channel access period may include a scheduled contention period during which multiple synchronized APs contend for access, followed by a communication period during which the successful AP holds a TXOP. In some implementations, synchronized APs may schedule periodically recurring synchronized channel access periods by periodically transmitting quiet elements. The quiet elements establish recurring quiet periods during which legacy devices are not permitted to transmit. For example, one or more synchronized APs may transmit a management frame (e.g., a beacon frame or a probe response frame) that includes one or more quiet elements specifying corresponding quiet periods. In some implementations, the management frame containing the quiet elements may further include one or more quiet override elements, each associated with a corresponding quiet element. The quiet override elements indicate to the synchronized APs that the quiet period established by the corresponding quiet element will be used for synchronized channel access and, therefore, that the synchronized APs are permitted to contend for access during the corresponding contention period.

[0088] In some implementations of synchronized channel access described herein, a synchronized AP that wins contention after one or more consecutive contention periods during which no synchronized AP wins contention may be eligible for an extended TXOP. In some such implementations, the length of the extended TXOP may be based on the number (quantity) of consecutive contention periods during which no synchronized AP wins contention. For example, the length of the extended TXOP may be an integer multiple of the normal maximum duration of the TXOP, where the value of the integer is equal to the number of consecutive contention periods determined to have been missed (i.e., contention periods during which no synchronized AP wins contention).

[0089] Specific implementations of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages. In some implementations, the described techniques may be used to facilitate coexistence between wireless communication devices configured for synchronous channel access and wireless communication devices that are not configured for synchronous channel access. Some implementations ensure that wireless communication devices that support synchronous channel access are provided with sufficient access to the wireless medium to, for example, meet their throughput and latency requirements. For example, some implementations enable efficient use of the wireless medium by reserving a wireless channel for use by an AP to transmit downlink communications to associated STAs and to schedule uplink communication transmissions from associated STAs during a synchronous channel access period. As another example, some implementations enable efficient use of the wireless channel by granting a wireless communication device configured for synchronous channel access an extended time duration for communicating with an associated station (STA).

[0090] Figure 9 Synchronous channel access techniques according to some implementations are shown. For example, Figure 9 The synchronized recurring channel access period 902 (eg, comprising a first channel access period 9021, a second channel access period 9022, and a third channel access period 9023) is shown. The channel access period 902 is based on a time interval τ. 接入 Each channel access period 902 includes a channel access period having a duration τ at the beginning of the channel access period. 争用 Each channel access period 902 may also include a channel access period having a duration τ 通信 9061, 9062, and 9063). In some implementations, only during the contention period 904 at the beginning of the scheduled channel access period 902, an AP that enables synchronized channel access and desires to communicate on the wireless channel contends for access. In some implementations, between adjacent channel access periods 902, there may be a contention period of duration τ 开放An open period during which the wireless medium is open for conventional contention-based access by other wireless communication devices (and optionally also by synchronized APs), as governed by, for example, the DCF.

[0091] Figure 10 A flow chart illustrating an example process 1000 for accessing via a synchronous channel according to some implementations is shown. The operations of process 1000 may be implemented by an AP or components thereof as described herein. For example, process 1000 may be performed by a wireless communication device (such as the one described above with reference to FIG. Figure 4 In some implementations, process 1000 may be performed by an AP configured for access via a synchronous channel (such as the wireless communication device 400 described above). Figure 1 and 5A 1 and 502 described herein).

[0092] In some implementations, in block 1002, a wireless communication device exchanges wireless packets with at least a first group of wireless communication devices. The wireless packets include channel access information establishing one or more recurring synchronized channel access periods. In some implementations, the channel access information is conveyed by one or more silence elements and one or more silence override elements included within the wireless packets exchanged in block 1002. Each silence element indicates to the second group of wireless communication devices that they are not permitted to transmit on the wireless channel during the silence period defined by the silence element. In some implementations, the silence override element indicates to the first group of wireless communication devices whether, for each of one or more of the silence elements, they are permitted to contend for access to the wireless channel during a contention period within the silence period defined by the corresponding silence element. In this way, the first group of wireless communication devices can schedule periodically recurring synchronized channel access periods by establishing periodic silence periods, such as with reference to FIG. Figure 9 A synchronized channel access period 902 is described.

[0093] If the silence override element indicates that the first group of wireless communication devices is permitted to contend for access during a corresponding contention period in each of the one or more upcoming silence periods, each of the first group of wireless communication devices may contend for access to the wireless channel during one or more of the contention periods indicated by the corresponding silence element and the silence override element in block 1004. If the wireless communication device wins the contention during one of the contention periods 904 in block 1004, the wireless communication device is the owner of the TXOP on the wireless channel during the corresponding communication period 906 in the corresponding channel access period 902. The wireless communication device may then exchange one or more wireless data packets on the wireless channel during the TXOP.

[0094] As described above, a silence element establishes a recurring silence period during which a compatible device that receives the silence element is generally not permitted to transmit. In this way, access to synchronized channels can be protected. For example, compatible devices may include a first group of wireless communication devices and a second group of wireless communication devices. The first group of wireless communication devices is an AP that supports access to synchronized channels (synchronized APs). However, although generally no device is permitted to contend for access during a silence period, a silence override element indicates to the first group of wireless communication devices that the silence period established by the corresponding silence element will be used for access to synchronized channels and thus the first group of wireless communication devices are permitted to contend for access during the corresponding contention period. In addition, STAs that support access to synchronized channels may also understand the silence override element and may thereby be configured to receive DL communications from the associated synchronized AP during the silence period and transmit UL communications to the associated AP in response to receiving a trigger frame from the associated AP during the silence period.

[0095] The second group of wireless communication devices may include legacy devices, which may be configured to operate in accordance with IEEE 802.11ax or an earlier revision or version of the IEEE 802.11 family of standards, but not configured to operate in accordance with IEEE 802.11be or a later revision or version of the IEEE 802.11 family of standards. The second group of wireless communication devices may also include devices that do not support, have been disabled, or do not implement access to synchronous channels for some reason. The second group of wireless communication devices may be configured to interpret silence elements, but may not be configured to interpret silence override elements.

[0096] For example, exchanging wireless packets including channel access information in block 1002 may include broadcasting, multicasting, or otherwise transmitting or receiving frames such as management frames that include or indicate silence elements and silence override elements. Figure 9 Channel access information including silence elements and silence override elements may be shared in beacons 908 (including beacons 9081, 9082, and 9083) or in probe response frames. For example, beacon 9081 may include a first silence element and a silence override element identifying a first silence period to be used as a channel access period 9021 by a first group of wireless communication devices.

[0097] In some implementations or instances where the wireless communication device may or may not be a master (or controller) AP (or may or may not be configured to operate within a master AP), the wireless communication device may transmit wireless packets including channel access information to other synchronized APs in the first group of wireless communication devices in block 1002. Alternatively, in some other implementations or instances, again where the wireless communication device may or may not be a master (or controller) AP (or may or may not be configured to operate within a master AP), the wireless communication device may receive wireless packets including channel access information from at least one other synchronized AP in block 1002.

[0098] The channel access information exchanged in block 1002 may include various channel access parameters associated with a recurring channel access period 902, such as, for example, one or more of the following: one or more relevant wireless channels defining scheduled channel access thereto, a start time for the next channel access period 902, a time interval τ between the beginnings of consecutive channel access periods 902, and a time interval τ between the beginnings of consecutive channel access periods 902. 接入 , the duration of each contention period 904 τ 争用 , the duration of each communication period 906 τ 通信 , or the total duration of each channel access period 902. For example, each silence element may be as shown in FIG. Figure 8 The described silence element 800 includes some or all of the following: element ID, length, silence count, silence period, silence duration, and silence offset, including information indicating the duration of the silence period and the beginning of the next silence period. As described above, each silence period can be repeated according to TBTT or other time intervals.

[0099] As described above, although devices are generally not permitted to contend for access during a silence period, the silence override element indicates to the first group of wireless communication devices that the silence period established by the corresponding silence element will be used for access via the synchronized channel, and thereby the first group of wireless communication devices are permitted to contend for access during the corresponding contention period 904 in the corresponding synchronized channel access period 902. Figure 11An example silence override element 1100 is shown that can be used to signal an override of a corresponding silence period. In the example shown, the silence override element 1100 includes multiple fields, including an element ID 1102, a length 1104, and a silence override map 1106, as well as, in some implementations, a duration field 1108 or a reserved field 1110. Element ID 1102 can be a unique identifier for the silence override element 1100. Length 1104 can indicate the length of the silence override element 1100. Silence override map 1106 can include a bitmap in which each bit is associated with a corresponding silence element. The value of each bit in bitmap 1106 can indicate whether the silence period defined by the corresponding silence element will be used for the synchronized channel access period 902, and thus whether the first group of wireless communication devices is permitted to contention access during the contention period defined by the silence element associated with that bit in the corresponding channel access period. Duration field 1108 can indicate the duration of each contention period. For example, the duration field 1108 may include a 4-bit value indicating the duration to be used for all contention periods (in some other implementations, the duration field 1108 may include multiple subfields that each indicate the duration of a corresponding contention period in a corresponding silent period). In some other examples, another field in a beacon or other management frame shared by synchronized APs may be used to signal the duration of the contention period.

[0100] As described above, if the wireless communication device wins contention during one of the contention periods 904 in block 1004, the wireless communication device is the owner of the TXOP on the wireless channel during the corresponding communication period 906 in the corresponding channel access period 902. The wireless communication device may then exchange one or more wireless data packets on the wireless channel during the TXOP. Figure 12 A flow chart illustrating a process 1200 for exchanging one or more wireless data packets is shown. The operations of process 1200 may be implemented by an AP or its components as described herein. For example, process 1200 may be implemented by a wireless communication device (such as the one described above with reference to FIG. Figure 4 In some implementations, process 1200 may be performed by an AP configured for synchronous channel access (such as the wireless communication device 400 described above). Figure 1 and 5A In some implementations, process 1200 is performed with reference to one of the APs 102 and 502 described herein. Figure 10 Block 1004 of the depicted process 1000 is performed after contention access.

[0101] In block 1202, the wireless communication device obtains a TXOP based on contention access in block 1004. In block 1204, the wireless communication device may then exchange one or more wireless data packets on a wireless channel during the TXOP. For example, in block 1206, the wireless communication device may transmit DL data to an associated STA. Additionally or alternatively, the wireless communication device may receive UL data from an associated STA. For example, in block 1208, the wireless communication device may transmit one or more trigger frames to one or more STAs allocating resources for UL transmission to the STAs, and in response, in block 1210, receive one or more wireless packets including UL data from each of the one or more STAs.

[0102] In some implementations, an AP may signal its support for synchronized channel access to other synchronized APs (and to STAs) in management frames (such as beacon frames and probe response frames, or other frames transmitted between synchronized APs). For example, a synchronized AP may signal its support for synchronized channel access in an Operation element included in a beacon, probe response, or other frame. A synchronized AP may also receive management frames, such as probe requests, from STAs indicating that the STA supports synchronized channel access. For example, such a STA may signal its support for synchronized channel access in a Capabilities element included in a Probe Request frame.

[0103] In some implementations, a synchronized AP may receive one or more explicit synchronization signals from a dedicated controller or another AP operating as a master (or controlling) AP. The APs may synchronize their respective clocks based on the synchronization signals to facilitate the implementation of the recurring channel access period. In some other implementations, the AP may synchronize its clock based on receiving various frames (e.g., beacons or other management frames, control frames, or data frames) from other APs participating in the recurring channel access period.

[0104] Some implementations of the synchronized channel access techniques described herein may also be used in conjunction with target wake time (TWT) techniques, such as those defined in IEEE 802.11ax. For example, a wireless communication device may transmit information to one or more associated STAs indicating a schedule for one or more wake-up periods during which the one or more STAs will wake up to transmit or receive wireless packets to or from the wireless communication device. In such implementations, the one or more wake-up periods are timed to occur within a channel access period associated with a silent period.

[0105] Figure 13 A block diagram of an example wireless communication device 1300 is shown according to some implementations. In some implementations, the wireless communication device 1300 is configured to perform the above-mentioned Figure 9 and12 One or more of the processes 900 and 1200 described above. The wireless communication device 1300 may be the one described above with reference to Figure 4 Example implementations of the wireless communication device 400 described herein. For example, the wireless communication device 1300 may be a chip, SoC, chipset, package, or device that includes at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem). In some implementations, the wireless communication device 1300 may be a processor for use in an AP (such as those described above with reference to FIG. Figure 1 and 5A In some other implementations, the wireless communication device 1300 may be an AP that includes such a chip, SoC, chipset, package, or device, as well as at least one transmitter, at least one receiver, and at least one antenna.

[0106] Wireless communication device 1300 includes a packet switching module 1302, a channel access management module 1304, and a contention module 1306. Portions of one or more of modules 1302, 1304, and 1306 can be implemented at least in part in hardware or firmware. For example, packet switching module 1302 can be implemented at least in part by a modem (such as modem 402). In some implementations, at least some of modules 1302, 1304, and 1306 are implemented at least in part as software stored in a memory (such as memory 408). For example, portions of one or more of modules 1302, 1304, and 1306 can be implemented as non-transitory instructions (or "code") that can be executed by a processor (such as processor 406) to perform the functions or operations of the corresponding module.

[0107] The packet switching module 1302 is configured to generate, transmit, and receive PDUs, including multi-user PDUs and single-user PDUs. For example, the packet switching module 1302 may be implemented by the PHY layer and the MAC layer. The packet switching module 1302 is generally configured to generate MPDUs and encode these MPDUs into code blocks. The code blocks may then be encoded into code words. The packet switching module 1302 may then map the code words to symbols and modulate the symbols onto multiple subcarriers as PPDUs. Similarly, the packet switching module 1302 is configured to receive PPDUs, demodulate and de-map the symbols to code words, decode the code words, and decode the MPDUs based on the decoded code words.

[0108] The packet exchange module 1302 is configured to exchange wireless packets with at least a first group of wireless communication devices. For example, the packet exchange module 1302 may be configured to perform a reference Figure 10The packet exchange module 1302 may exchange wireless packets including channel access information that establishes one or more recurring synchronized channel access periods. In some implementations, the channel access information may be conveyed by one or more silence elements and one or more silence override elements included within the wireless packets. For example, each silence element and silence override element may be a reference to a respective Figure 8 and 11 1. An example of a silence element 800 or silence override element 1100 is described. Each silence element indicates to the second group of wireless communication devices that they are not permitted to transmit on the wireless channel during the silence period defined by the silence element. In some implementations, the silence override element indicates to the first group of wireless communication devices whether, for each of one or more of the silence elements, they are permitted to contend for access to the wireless channel during a contention period within the silence period defined by the corresponding silence element. In this way, the first group of wireless communication devices can schedule periodically recurring synchronized channel access periods by establishing periodic silence periods.

[0109] The first group of wireless communication devices are APs that support access via a synchronization channel (synchronized APs). Although generally no device is permitted to contend for access during a silence period, a silence override element indicates to the first group of wireless communication devices that the silence period established by the corresponding silence element will be used for access via a synchronization channel and thus the first group of wireless communication devices are permitted to contend for access during the corresponding contention period.

[0110] The second group of wireless communication devices may include legacy devices, which may be configured to operate in accordance with IEEE 802.11ax or an earlier revision or version of the IEEE 802.11 family of standards, but not configured to operate in accordance with IEEE 802.11be or a later revision or version of the IEEE 802.11 family of standards. The second group of wireless communication devices may also include devices that do not support, have been disabled, or do not implement access to synchronous channels for some reason. The second group of wireless communication devices may be configured to interpret silence elements, but may not be configured to interpret silence override elements.

[0111] Exchanging wireless packets including channel access information may include broadcasting, multicasting, or otherwise transmitting or receiving frames, such as management frames, that include or indicate silence elements and silence override elements. In some implementations or instances where the wireless communication device may or may not be a master (or controller) AP (or may or may not be configured to operate within a master AP), the packet exchange module 1302 may transmit wireless packets including channel access information to other synchronized APs in the first group of wireless communication devices when exchanging wireless packets. Alternatively, in some other implementations or instances where the wireless communication device may or may not be a master (or controller) AP (or may or may not be configured to operate within a master AP), the packet exchange module 1302 may receive wireless packets including channel access information from at least one other synchronized AP when exchanging wireless packets.

[0112] The packet switching module 1302 may also be configured to perform a reference Figure 12 1204 of the described process 1200. As described above, if the wireless communication device wins contention during a contention period, the wireless communication device is the owner of the TXOP on the wireless channel during the corresponding communication period in the corresponding channel access period. The packet exchange module 1302 can then exchange one or more wireless data packets on the wireless channel during the TXOP. For example, the packet exchange module 1302 can transmit DL data to the associated STA. Additionally or alternatively, the packet exchange module 1302 can receive UL data from the associated STA. For example, the packet exchange module 1302 can transmit one or more trigger frames to one or more STAs that allocate resources for UL transmission to the STAs, and in response, receive one or more wireless packets including UL data from each of the one or more stations.

[0113] The channel access management module 1304 is configured to extract channel access information including one or more silence elements and one or more silence override elements from the wireless packet. The channel access information may include various channel access parameters associated with a recurring channel access period, such as, for example, one or more of the following: one or more relevant wireless channels for which scheduled channel access is defined, a start time for a next channel access period, a time interval τ between the beginnings of consecutive channel access periods, and a time interval τ between the beginnings of consecutive channel access periods. 接入 , the duration of each contention period τ 争用 , the duration of each communication period τ 通信 , or the total duration of each channel access period. For example, each silence element can be as shown in the reference Figure 8The silence element 800 is described and includes some or all of the following: element ID, length, silence count, silence period, silence duration, and silence offset, including information indicating the duration of the silence period and the beginning of the next silence period. Each silence override element can be as described with reference to Figure 11 A silence override element 1100 is depicted and includes some or all of an element ID, a length, a silence override map 1106, and a contention period duration.

[0114] In some implementations, the channel access management module 1304 is generally configured to instruct the packet switching module 1302 when to transmit wireless packets establishing access to the synchronized channel. The channel access management module 1304 is also configured to identify contention periods within a recurring channel access period and instruct the contention module 1306 when to contend for access. The channel access management module 1304 can be further configured to instruct the packet switching module 1302 when to transmit wireless data packets during corresponding communication periods within the channel access period.

[0115] In some implementations, the channel access management module 1304 is further configured to synchronize its clock with the clocks of other APs to facilitate synchronized channel access. For example, the packet switching module 1302 may receive one or more explicit synchronization signals from a dedicated controller or another AP operating as a master AP. The channel access management module 1304 may synchronize its clock based on the synchronization signals to facilitate implementation of the recurring channel access period. In some other implementations, the channel access management module 1304 may synchronize its clock based on receiving various frames (e.g., beacons or other management frames, control frames, or data frames) from other APs participating in the recurring channel access period.

[0116] If the channel access management module 1304 determines that the silence override element indicates that the first group of wireless communication devices is permitted to contend for access during a corresponding contention period in each of one or more upcoming silent periods, the module then instructs the contention module 1306 to contend for access to the wireless channel during one or more of the contention periods indicated by the corresponding silent element and the silence override element. If the contention module 1306 wins the contention during one of these contention periods, the wireless communication device is the owner of the TXOP on the wireless channel during the corresponding communication period in the corresponding channel access period. The contention module 1306 can then inform the packet switching module 1302 accordingly.

[0117] Figure 14 Another flow chart illustrating an example process 1400 for synchronous channel access according to some implementations is shown. The process 1400 may be performed by a wireless communication device (such as the one described above with reference to FIG. Figure 4In some implementations, process 1400 may be performed by an AP configured for access via a synchronous channel (such as the wireless communication device 400 described above). Figure 1 and Figure 5A The method is performed by a wireless communication device operating at or within one of the described APs 102 and 502.

[0118] In some implementations, in block 1402, the wireless communication device exchanges wireless packets including channel access information with at least a first group of wireless communication devices. In some implementations, the channel access information indicates a first schedule of recurring channel access periods for a wireless channel. In some such implementations, each channel access period includes a corresponding contention period, e.g., at the start of the channel access period, during which a first group of wireless communication devices, including the wireless communication device, is scheduled to contend for access to the wireless channel. The first group of wireless communication devices are wireless communication devices that support synchronized channel access as described herein, including APs and STAs. For example, STAs that support synchronized channel access may also understand the channel access information and remain silent during the channel access period unless triggered by their associated AP.

[0119] Figure 15 Synchronized channel access techniques according to some implementations are shown. For example, Figure 15 The synchronized recurring channel access period 1502 (eg, comprising a first channel access period 15021, a second channel access period 15022, and a third channel access period 15023) is shown. The channel access period 1502 is based on a time interval τ. 接入 Each channel access period 1502 includes a time duration τ at the beginning of the channel access period. 争用 Each channel access period 1502 may also include a channel access period having a duration τ 通信 1506 ) (e.g., communication periods 15061, 15062, and 15063). Only during the contention period 1504 at the beginning of the scheduled channel access period 1502, an AP that enables synchronized channel access and desires to communicate on the wireless channel contends for access. Between adjacent channel access periods 1502, there may be a contention period of duration τ 开放 An open period during which the wireless medium is open for conventional contention-based access, governed by, for example, the above-mentioned CMSA / CA techniques.

[0120] Refer again Figure 14In some implementations, exchanging wireless packets including channel access information with at least one other wireless communication device in block 1402 includes broadcasting, multicasting, otherwise transmitting, or receiving frames, such as management frames (e.g., beacon frames or probe response frames), including or indicating channel access information. In some implementations or instances where the wireless communication device may or may not be a master (or controller) AP (or may or may not be configured to operate within a master AP), the wireless communication device may transmit wireless packets including channel access information to other synchronized APs in the first group of wireless communication devices in block 1402. Alternatively, in some other implementations or instances where the wireless communication device may or may not be a master (or controller) AP (or may or may not be configured to operate within a master AP), the wireless communication device may receive wireless packets including channel access information from at least one other synchronized AP in block 1402.

[0121] The channel access information may include various channel access parameters associated with the recurring channel access period 1502, such as, for example, one or more of the following: one or more relevant wireless channels defining the scheduled channel access thereto, a start time of the next channel access period 1502, a time interval τ between the beginnings of consecutive channel access periods 1502, and a time interval τ between the beginnings of consecutive channel access periods 1502. 接入 , the duration of each contention period 1504 τ 争用 , the duration of each communication period 1506 is τ 通信 , or the total duration of each channel access period 1502.

[0122] In block 1404, the wireless communication device contends for access to the wireless channel during a number of contention periods 1504. For example, in a first contention period 15041 starting at time t1, the wireless communication device contends for access and wins the contention. As a result, the wireless communication device contends for access to the wireless channel during a contention period with a maximum duration τ 通信 The wireless communication device becomes the owner of the TXOP on the wireless channel during the corresponding communication period 15061. The wireless communication device exchanges one or more wireless data packets on the wireless channel during the TXOP, for example, referring to Figure 12 Descriptive.

[0123] At time t2, the wireless communication device again contends for access to the wireless channel during a second contention period 15042. However, this time, the wireless communication fails to win the contention. Indeed, in the illustrated example, no synchronized AP wins contention during the second contention period 15042 due to, for example, the detection of interfering transmissions from a wireless communication device that does not support or participate in synchronized channel access. At time t3, the wireless communication device again contends for access to the wireless channel during a third contention period 15043. The wireless communication device again fails to win contention. Furthermore, no other synchronized AP wins contention during the third contention period 15043, again due to, for example, the detection of interfering transmissions from a wireless communication device that does not support or participate in synchronized channel access. In some implementations, based on the failure to win contention in the second and third contention periods 15042 and 15043, respectively, the wireless communication device may determine, in block 1406, the number (two in the illustrated example) of previous consecutive channel access periods during which no device in the first group of wireless communication devices won contention.

[0124] At time t4, the wireless communication device again contends for access to the wireless channel during a fourth contention period 15044. This time, the wireless communication device wins the contention and thereby becomes the owner of the TXOP 15062 on the wireless channel in block 1408. In block 1410, having obtained the TXOP 15062, the wireless communication device may then exchange one or more wireless data packets on the wireless channel during the TXOP 15062, e.g., with reference to FIG. Figure 12 However, this time the duration of the TXOP may be extended. In some implementations, a synchronized AP among the synchronized APs that wins contention after one or more consecutive contention periods during which no synchronized AP wins contention may be eligible for an extended TXOP. In some such implementations, the length of the extended TXOP may be based on the number (e.g., quantity) of consecutive contention periods during which no synchronized AP wins contention. In some implementations, the length of the subsequent extended TXOP 15062 may be calculated by increasing the normal maximum duration τ of the TXOP by 15062. 通信 For example, the length of the extended TXOP 15062 may be, for example, the normal maximum duration τ 通信 An integer multiple of , where the value of the integer is equal to the number of consecutive contention periods determined to have been missed (i.e., contention periods during which no synchronized AP won contention). Figure 15 In the example shown, a wireless communication device that wins contention during the fourth contention period 15044 may be eligible for a subsequent TXOP 15062 having a maximum duration τ that may be normal due to having missed two consecutive channel access periods. 通信 Twice the duration.

[0125] A first group of wireless communication devices (APs that support and participate in synchronized channel access) including the wireless communication device may be configured to determine whether an interfering transmission detected during a synchronized channel access contention period is from a device that is not participating in synchronized channel access (i.e., a device outside the first group of wireless communication devices). For example, as described above, the AP may be configured to determine whether these APs and STAs support synchronized channel access by receiving operation or capability elements from its neighboring APs and STAs. In some implementations, the wireless communication device may determine whether a transmission detected during a synchronized channel access contention period is from a device participating in synchronized channel access based on an address associated with the device participating in synchronized channel access indicated in a wireless transmission. Based on the address, the wireless communication device may access an internal data store to determine whether the address is associated with a device that supports synchronized channel access (e.g., as previously determined based on receiving an operation or capability element from the device).

[0126] Figure 16 FIG2 shows a block diagram of an example wireless communication device 1600 according to some implementations. In some implementations, the wireless communication device 1600 is configured to perform the above-mentioned respective references to Figure 12 and 14 One or more of the processes 1200 and 1400 described above. The wireless communication device 1600 may be the one described above with reference to Figure 4 Example implementations of the wireless communication device 400 described herein. For example, the wireless communication device 1600 may be a chip, SoC, chipset, package, or device that includes at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem). In some implementations, the wireless communication device 1600 may be a processor for use in an AP (such as those described above with reference to FIG. Figure 1 and 5A In some other implementations, the wireless communication device 1600 may be an AP that includes such a chip, SoC, chipset, package, or device, as well as at least one transmitter, at least one receiver, and at least one antenna.

[0127] Wireless communication device 1600 includes a packet switching module 1602, a channel access management module 1604, and a contention module 1606. Portions of one or more of modules 1602, 1604, and 1606 can be implemented at least in part in hardware or firmware. For example, packet switching module 1602 can be implemented at least in part by a modem (such as modem 402). In some implementations, at least some of modules 1602, 1604, and 1606 are implemented at least in part as software stored in a memory (such as memory 408). For example, portions of one or more of modules 1602, 1604, and 1606 can be implemented as non-transitory instructions (or "code") that can be executed by a processor (such as processor 406) to perform the functions or operations of the corresponding module.

[0128] The packet switching module 1602 is configured to generate, transmit, and receive PDUs, including multi-user PDUs or single-user PDUs. For example, the packet switching module 1602 may be implemented by the PHY layer and the MAC layer. The packet switching module 1602 is generally configured to generate an MPDU and encode the MPDU into a code block. The code block may then be encoded into a codeword. The packet switching module 1602 may then map the codeword to a code symbol and modulate the code symbol onto multiple subcarriers as a PPDU. Similarly, the packet switching module 1602 is configured to receive a PPDU, demodulate and de-map the code symbol to a codeword, decode the codeword, and decode the MPDU based on the decoded codeword.

[0129] The packet exchange module 1602 is configured to exchange wireless packets with at least a first group of wireless communication devices. The first group of wireless communication devices are APs that support synchronous channel access (synchronous APs). For example, the packet exchange module 1602 may be configured to perform a reference Figure 10 Block 1002 of the described process 1000. The packet exchange module 1602 can exchange wireless packets with at least a first group of wireless communication devices. The wireless packets include channel access information establishing one or more recurring synchronized channel access periods.

[0130] Exchanging wireless packets including channel access information may include broadcasting, multicasting, or otherwise transmitting or receiving frames, such as management frames, including or indicating channel access information. In some implementations or instances where the wireless communication device may or may not be a master (or controller) AP (or may or may not be configured to operate within a master AP), the packet exchange module 1602 may transmit wireless packets including channel access information to other synchronized APs in the first group of wireless communication devices when exchanging wireless packets. Alternatively, in some other implementations or instances where the wireless communication device may or may not be a master (or controller) AP (or may or may not be configured to operate within a master AP), the packet exchange module 1602 may receive wireless packets including channel access information from at least one other synchronized AP when exchanging wireless packets.

[0131] The packet switching module 1602 may also be configured to perform a reference Figure 12 Block 1204 of the described process 1200. As described above, if the wireless communication device wins contention during a contention period, the wireless communication device is the owner of the TXOP on the wireless channel during the corresponding communication period in the corresponding channel access period. The packet exchange module 1602 can then exchange one or more wireless data packets on the wireless channel during the TXOP. For example, the packet exchange module 1602 can transmit DL data to the associated STA. Additionally or alternatively, the packet exchange module 1602 can receive UL data from the associated STA. For example, the packet exchange module 1602 can transmit one or more trigger frames to one or more STAs that allocate resources for UL transmission to the STAs, and in response, receive one or more wireless packets including UL data from each of the one or more stations.

[0132] The channel access management module 1604 is configured to extract channel access information from the wireless packet. The channel access information may include various channel access parameters associated with a recurring channel access period, such as, for example, one or more of the following: one or more relevant wireless channels for which scheduled channel access is defined, a start time for the next channel access period, a time interval τ between the beginnings of consecutive channel access periods, and a time interval τ between the beginnings of consecutive channel access periods. 接入 , the duration of each contention period τ 争用 , the duration of each communication period τ 通信 , or the total duration of each channel access period.

[0133] In some implementations, the channel access management module 1604 is generally configured to instruct the packet switch module 1602 when to transmit wireless packets establishing access to the synchronized channel. The channel access management module 1604 is also configured to identify contention periods within a recurring channel access period and instruct the contention module 1606 when to contend for access. The channel access management module 1604 can be further configured to instruct the packet switch module 1602 when to transmit wireless data during corresponding communication periods within the channel access period.

[0134] In some implementations, the channel access management module 1604 is further configured to synchronize its clock with the clocks of other APs to facilitate synchronized channel access. For example, the packet switching module 1602 may receive one or more explicit synchronization signals from a dedicated controller or another AP operating as a master AP. The channel access management module 1604 may synchronize its clock based on the synchronization signals to facilitate implementation of the recurring channel access period. In some other implementations, the channel access management module 1604 may synchronize its clock based on receiving various frames (e.g., beacons or other management frames, control frames, or data frames) from other APs participating in the recurring channel access period.

[0135] If the channel access management module 1604 determines that a contention period for the synchronized channel has begun, it instructs the contention module 1606 to contend for access to the wireless channel. If the contention module 1606 does not win contention during the contention period, in some implementations, the channel access management module 1604 may determine the number of previous consecutive channel access periods during which no device in the first group of wireless communication devices won contention.

[0136] If the contention module 1606 wins contention during a contention period, it is the owner of the TXOP on the wireless channel during the corresponding communication period in the corresponding channel access period. In some implementations, if the contention module 1606 wins contention after one or more consecutive contention periods during which no synchronized AP wins contention, it may determine an extended TXOP for the communication period and inform the packet exchange module 1602 accordingly. In some such implementations, the length of the extended TXOP may be based on the number (e.g., quantity) of consecutive contention periods during which no synchronized AP wins contention. In some implementations, the length of the subsequent extended TXOP 15062 may be determined by increasing the normal maximum duration τ of the TXOP. 通信 For example, the length of the extended TXOP 15062 may be the normal maximum duration τ 通信 An integer multiple of , where the value of the integer is equal to the number of consecutive contention periods determined to have been missed (ie, contention periods during which no synchronized AP won contention).

[0137] The channel access management module 1604 may be further configured to determine whether an interfering transmission detected during the synchronized channel access contention period is from a device not participating in the synchronized channel access (i.e., a device outside the first group of wireless communication devices). For example, as described above, an AP may be configured to determine whether its neighboring APs and STAs support synchronized channel access by receiving operation or capability elements from those APs and STAs. In some implementations, the channel access management module 1604 may determine whether a transmission detected during the synchronized channel access contention period is from a device participating in the synchronized channel access based on an address associated with the device participating in the synchronized channel access indicated in the wireless transmission. Based on the address, the channel access management module 1604 may determine whether the address is associated with a device that supports synchronized channel access (e.g., as previously determined based on receiving an operation or capability element from the device).

[0138] As used herein, unless explicitly indicated otherwise, "or" is intended to be interpreted in an inclusive sense. For example, "a or b" may include only a, only b, or a combination of a and b. 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 individual members. For example, "at least one of a, b, or c" is intended to encompass 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.

[0139] 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 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.

[0140] Various modifications to the implementations described in this disclosure may be apparent to those skilled in the art, and the general 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 accorded the widest scope consistent with this disclosure, the principles, and the novel features disclosed herein.

[0141] 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, although features may be described above as functioning in a particular combination and even initially claimed as such, one or more features from a claimed combination may in some cases be omitted from that combination, and a claimed combination may be directed to a subcombination, or variations of a subcombination.

[0142] Similarly, although the 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 of the illustrated operations in order 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 flow diagram. However, other operations not depicted may be incorporated into the schematically illustrated example processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the illustrated operations. In some environments, multitasking and parallel processing may be advantageous. In addition, the separation of the various system components in the implementations 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 method for wireless communication by a wireless access point AP, comprising: transmitting first information indicating at least one silent period, during which a group of wireless stations STA do not transmit on a wireless channel; transmitting second information indicating a schedule of awake periods during which a subset of the set of wireless STAs are to awaken, the at least one silent period at least partially overlapping with at least one of the awake periods, the second information indicating to the subset of wireless STAs that they can receive communications or transmit communications in response to a trigger during the at least one awake period regardless of the at least one silent period at least partially overlapping with the at least one awake period; as well as During the at least one awake period, communications are transmitted to at least one wireless STA in the subset of wireless STAs at a time that is during the at least one silent period. 2 . The method of claim 1 , wherein the first information indicates a periodicity of the at least one silent period, a duration of the at least one silent period, and a beginning of the at least one silent period.

3. The method of claim 1, wherein the wireless AP is associated with a first basic service set (BSS) color, the method further comprising: detecting, during the at least one awake period, wireless transmissions from wireless STAs that are not in the subset of wireless STAs; as well as A second BSS color associated with the wireless STA is identified, wherein the transmission of the communication is based on determining that the second BSS color is different than the first BSS color.

4. The method of claim 1, wherein the communication comprises a trigger that triggers the at least one wireless STA to transmit a communication during the at least one awake period.

5. A method for wireless communication by a wireless station STA, comprising: receiving first information indicating at least one silent period during which a group of wireless stations STA do not transmit on a wireless channel; receiving second information indicating a schedule of awake periods during which a subset of wireless STAs of the set of wireless STAs are to awaken, the subset of wireless STAs including the wireless STA, the at least one silent period at least partially overlapping with at least one of the awake periods, the second information indicating to the subset of wireless STAs that they can receive communications or transmit communications in response to a trigger during the at least one awake period despite the at least one silent period at least partially overlapping with the at least one awake period; as well as During the at least one awake period, a communication is received at a time during the at least one silent period or a communication is transmitted in response to a trigger.

6. The method of claim 5, wherein the first information indicates a periodicity of the at least one silent period, a duration of the at least one silent period, and a beginning of the at least one silent period.

7. A wireless access point AP, comprising: one or more processors; as well as One or more memories coupled to the one or more processors and storing processor-executable code, the processor-executable code, when executed by the one or more processors, configured to cause the wireless AP to: transmitting first information indicating at least one silent period, during which a group of wireless stations STA do not transmit on a wireless channel; transmitting second information indicating a schedule of awake periods during which a subset of the set of wireless STAs are to awaken, the at least one silent period at least partially overlapping with at least one of the awake periods, the second information indicating to the subset of wireless STAs that they can receive communications or transmit communications in response to a trigger during the at least one awake period regardless of the at least one silent period at least partially overlapping with the at least one awake period; as well as During the at least one awake period, communications are transmitted to at least one wireless STA in the subset of wireless STAs at a time that is during the at least one silent period.

8. The wireless AP of claim 7, wherein the first information indicates a periodicity of the at least one silent period, a duration of the at least one silent period, and a beginning of the at least one silent period.

9. The wireless AP of claim 7, wherein the wireless AP is associated with a first basic service set (BSS) color, and wherein the code, when executed by the one or more processors, is further configured to cause the wireless AP to: detecting, during the at least one awake period, wireless transmissions from wireless STAs that are not in the subset of wireless STAs; A second BSS color associated with the wireless STA is identified, wherein the transmission of the communication is based on determining that the second BSS color is different than the first BSS color.

10. The wireless AP of claim 7, wherein the communication comprises a trigger that triggers the at least one wireless STA to transmit a communication during the at least one awake period.

11. A wireless station STA, comprising: one or more processors; as well as one or more memories coupled to the one or more processors and storing processor-executable code configured to cause the wireless STA to: receiving first information indicating at least one silent period during which a group of wireless stations STA do not transmit on a wireless channel; receiving second information indicating a schedule of awake periods during which a subset of wireless STAs of the set of wireless STAs are to awaken, the subset of wireless STAs including the wireless STA, the at least one silent period at least partially overlapping with at least one of the awake periods, the second information indicating to the subset of wireless STAs that they can receive communications or transmit communications in response to a trigger during the at least one awake period despite the at least one silent period at least partially overlapping with the at least one awake period; as well as During the at least one awake period, a communication is received at a time during the at least one silent period or a communication is transmitted in response to a trigger.

12. The wireless STA of claim 11, wherein the first information indicates a periodicity of the at least one silent period, a duration of the at least one silent period, and a beginning of the at least one silent period.

13. A device for wireless communication by a wireless access point AP, comprising: means for transmitting first information indicating at least one silent period during which a group of wireless stations STA do not transmit on a wireless channel; means for transmitting second information indicating a schedule of awake periods during which a subset of the set of wireless STAs are to awaken, the at least one silent period at least partially overlapping with at least one of the awake periods, the second information indicating to the subset of wireless STAs that they can receive communications or transmit communications in response to a trigger during the at least one awake period regardless of the at least one silent period at least partially overlapping with the at least one awake period; as well as Means for transmitting, during the at least one awake period, a communication to at least one wireless STA in the subset of wireless STAs at a time that is during the at least one silent period.

14. A device for wireless communication by a wireless station STA, comprising: means for receiving first information indicating at least one silent period during which a group of wireless stations STA do not transmit on a wireless channel; means for receiving second information indicating a schedule of awake periods during which a subset of wireless STAs of the set of wireless STAs are to awaken, the subset of wireless STAs including the wireless STA, the at least one silent period at least partially overlapping with at least one of the awake periods, the second information indicating to the subset of wireless STAs that they can receive communications or transmit communications in response to a trigger during the at least one awake period regardless of the at least one silent period at least partially overlapping with the at least one awake period; as well as Means for receiving a communication during the at least one awake period at a time during the at least one silent period or transmitting a communication in response to a trigger.

15. A computer readable medium having stored thereon processor executable instructions for wireless communication by a wireless access point (AP), wherein when the processor executable instructions are executed by a processor, the wireless access point (AP) is configured to: transmitting first information indicating at least one silent period, during which a group of wireless stations STA do not transmit on a wireless channel; transmitting second information indicating a schedule of awake periods during which a subset of the set of wireless STAs are to awaken, the at least one silent period at least partially overlapping with at least one of the awake periods, the second information indicating to the subset of wireless STAs that they can receive communications or transmit communications in response to a trigger during the at least one awake period regardless of the at least one silent period at least partially overlapping with the at least one awake period; as well as During the at least one awake period, communications are transmitted to at least one wireless STA in the subset of wireless STAs at a time that is during the at least one silent period.

16. A computer readable medium having stored thereon processor executable instructions for wireless communication by a wireless station (STA), the processor executable instructions, when executed by a processor, for causing the wireless STA to: receiving first information indicating at least one silent period during which a group of wireless stations STA do not transmit on a wireless channel; receiving second information indicating a schedule of awake periods during which a subset of wireless STAs of the set of wireless STAs are to awaken, the subset of wireless STAs including the wireless STA, the at least one silent period at least partially overlapping with at least one of the awake periods, the second information indicating to the subset of wireless STAs that they can receive communications or transmit communications in response to a trigger during the at least one awake period despite the at least one silent period at least partially overlapping with the at least one awake period; as well as During the at least one awake period, a communication is received at a time during the at least one silent period or a communication is transmitted in response to a trigger.

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