TW202520777A - Txop duration negotiation to address asymmetric channel view for multiple primary channels - Google Patents

Abstract

This disclosure provides methods, components, devices and systems that may help determine transmit opportunity (TXOP) durations for an opportunistic primary channel (O-Primary) for a transmitter and receiver that may have different (asymmetric) views of a main primary (M-Primary) channel. An example method, performed at a first wireless node, generally includes switching from communicating via a first primary channel to communicating via a second primary channel, after a detection of an overlapping basic service set (BSS), outputting, for transmission on the second primary channel, a first frame indicating a requested duration for a transmission opportunity (TXOP) associated with the second primary channel, obtaining, after outputting the first frame, an indication of an allowed duration for the TXOP, and communicating with at least a second wireless node in accordance with the allowed duration for the TXOP.

Description

Solving TXOP duration negotiation for asymmetric channel views of multiple main channels

Cross-reference to related applications

This application claims priority to Indian Patent Application No. 202341072929 filed on October 26, 2023, which is assigned to the assignee of this application and is hereby expressly incorporated herein by reference in its entirety as if fully set forth herein and for all applicable purposes.

The present disclosure relates generally to wireless communications and, more particularly, to aspects related to mechanisms for determining transmit opportunity (TXOP) duration when a transmitter and a receiver have asymmetric channel views for a network supporting multiple channels competing for access to a wireless medium.

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

In some WLAN scenarios, devices share access to the wireless medium. In such scenarios, contention-based channel access is the mechanism used to share the wireless medium. This mechanism allows multiple devices to access the same wireless channel without a centralized coordinator, making it suitable for scenarios with a variable number of devices.

For example, a device that wants to transmit data first senses the wireless channel. This process is called carrier sensing, where the device first checks whether the channel is idle or busy. If the channel is sensed as busy, indicating that another device is currently transmitting, the carrier sensing device will wait for an idle period before attempting to transmit.

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

One aspect provides a method for wireless communication by a first wireless device, which is related to selecting a transmission opportunity (TXOP) duration when switching from communication via a first primary channel to communication via a second primary channel after detecting an overlapping basic service set (BSS). The first wireless device may output a first frame for transmission on the second primary channel, the first frame indicating a requested duration of a transmission opportunity (TXOP) associated with the second primary channel; after outputting the first frame, obtain an indication of an allowed duration of the TXOP; and communicate with at least one second wireless node according to the allowed duration of the TXOP.

One aspect provides a method for wireless communication by a second wireless device, which is related to selecting a transmission opportunity (TXOP) duration when switching from communication via a first primary channel to communication via a second primary channel after detecting an overlapping basic service set (BSS). The second wireless device may obtain a first frame on the second primary channel, the first frame indicating a requested duration of a transmission opportunity (TXOP) associated with the second primary channel; output an indication of an allowed duration of the TXOP transmitted in response to the first frame; and communicate with at least one first wireless node according to the allowed duration of the TXOP.

Other aspects provide: an apparatus operable, configured, or otherwise adapted to perform any one or more of the aforementioned methods and/or those methods described elsewhere herein; a non-transitory computer-readable medium containing instructions that, when executed by a processor of a device, cause the device to perform the aforementioned methods and those methods described elsewhere herein; a computer program product embodied on a computer-readable storage medium containing code for performing the aforementioned methods and those methods described elsewhere herein; and/or an apparatus comprising components for performing the aforementioned methods and those methods described elsewhere herein. For example, an apparatus may include a processing system, a device having a processing system, or processing systems cooperating through one or more networks.

Details of one or more embodiments of the subject matter described in the present disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the specification, drawings, and claims. Please note that the relative sizes of the following drawings may not be drawn to scale.

The following description is about some specific examples for the purpose of describing the innovative aspects of the present disclosure. However, it will be readily appreciated by those skilled in the art that the teachings herein can be applied in many different ways. Some or all of the described examples 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 Institute of Electrical and Electronics Engineers ( ^IEEE ) 802.11 standard, the IEEE 802.15 standard, the ^Bluetooth® standard defined by the Special Interest Group (SIG), or the Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards promulgated by the 3rd Generation Partnership Project (3GPP), among others. The described examples 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), orthogonal frequency division multiplexing (OFDM), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrier FDMA (SC-FDMA), spatial division multiple access (SDMA), rate-splitting multiple access (RSMA), multi-user shared access (MUSA), single-user (SU) multiple-input multiple-output (MIMO), and multi-user (MU)-MIMO. (MU-MIMO). The described examples may also be implemented using other wireless communication protocols or RF signals suitable for one or more of the following: a wireless personal area network (WPAN), a wireless local area network (WLAN), a wireless wide area network (WWAN), a wireless metropolitan area network (WMAN), or an Internet of Things (IoT) network.

Aspects generally relate to wireless communications and, more particularly, to techniques for determining a transmission opportunity (TXOP) duration for a network supporting multiple channels competing for access to a wireless medium.

Contention-based channel access generally refers to the mechanism used to share wireless media. A device that wants to transmit data first senses the wireless channel. This process is called carrier sensing, where the device first checks whether the channel is idle or busy. If the channel is sensed to be busy, indicating that another device is currently transmitting, the carrier sensing device will wait for an idle period before attempting to transmit.

Contention-based channel access can be used to share access in WLANs that support relatively large bandwidths. For example, IEEE 802.11be Extremely High Throughput (EHT), also known as Wi-Fi 7, has defined support for bandwidths up to 320 MHz. Within this large bandwidth, a 20 MHz channel is designated as the primary channel.

For example, FIG2 depicts a diagram 200 of an example bandwidth configuration for 160 MHz bandwidth, where the 20 MHz primary channel is labeled P20. Wi-Fi devices contend for access only on the primary channel, and access to a wider bandwidth (no matter how large) is contingent upon access to the primary channel.

Thus, if an overlapping basic service set (OBSS) station (STA) occupies the primary channel, another STA (in the BSS) can detect OBSS transmissions 202 while performing channel access on the primary channel. Because access to the wider bandwidth (for transmissions 206 in the BS) depends on access to the primary channel, the remainder of the bandwidth 204 remains unused, which results in lower throughput and longer latency.

However, in some WLAN scenarios, a WLAN device may be able to monitor additional 20 MHz channels within the operating bandwidth to contend for channel access. Such monitoring may be performed sequentially or in parallel. With sequential monitoring, when one 20 MHz primary channel is found to be busy, the device switches to the next 20 MHz channel to contend for access. With parallel monitoring, the device may monitor each 20 MHz channel simultaneously. In such scenarios, the initial primary channel is referred to as the primary primary channel (M-primary channel), and the additional 20 MHz channels/sub-channels are referred to as opportunistic primary channels (O-primary channels).

One potential challenge with using multi-primary channel access is how to determine the transmission opportunity (TXOP) duration when wireless nodes (e.g., access points (APs) and non-AP STAs) utilizing multiple channels for channel access have asymmetric views of one or more of the channels. Since other devices can set the network allocation vector or NAV based on the TXOP duration (and stay away from the medium before the NAV timer expires), the TXOP duration generally refers to a finite time period during which uncontended channel access is available to the station owning the channel. One benefit of the TXOP duration mechanism is that it can increase throughput and reduce latency by eliminating contention periods between transmissions.

The duration of the TXOP on the O-primary channel is generally determined based on the TXOP duration of the OBSS transmission detected on the M-primary channel. In large networks, the AP and STA have different (asymmetric) views of the M-primary channel which may result in different TXOP durations. For example, the AP and STA may detect different OBSS PPDUs. If the OBSS TXOP duration/NAV observed at the receiver (AP or STA) is shorter than the TXOP duration/NAV observed at the transmitter (STA or AP), there may be some ambiguity in the TXOP duration of the O-primary channel.

This ambiguity may make it unclear how long the receiver should wait before PPDU reception is complete, which may cause certain problems. For example, if the receiver is an AP, waiting for PPDU reception to be complete (and transmitting an acknowledgement/ACK) may cause backtracking compatibility issues. On the other hand, a receiver terminating PPDU reception early and switching back to the M-primary channel may cause performance loss on the O-primary channel, which reduces the potential gain of the multi-primary channel access feature.

However, aspects of the present disclosure provide a mechanism by which a transmitter and a receiver can effectively negotiate the TXOP of an O-primary channel. As will be described in more detail below, the transmitter and the receiver can exchange information about the TXOP duration allowed on the O-primary channel. In some cases, the NAV of the O-primary channel can be set after this exchange of information is completed.

Certain aspects of the subject matter described in this disclosure may be implemented to achieve one or more of the following potential advantages. In some examples, the described techniques may be used to set the TXOP duration of the O-primary channel in a manner that prevents excessive inhibition of other devices from competing for access on the O-primary channel. As a result, the techniques may result in improved system performance and better resource utilization.

Although some aspects of the present disclosure are described in the context of multi-primary channel access with an M-primary channel and one or more O-primary channels, the concepts and technical applications described herein are more broadly applicable to any type of system with different types of channels or links for competing channel access. In some embodiments, the techniques described herein may be applied in a system where the M-primary channel and the O-primary channel are sub-channels within the operating bandwidth (such as in multi-primary channel access). In some other embodiments, the techniques described herein may be applied in a situation where the M-primary channel and the O-primary channel are different links (such as in an enhanced multi-link single radio (eMLSR) AP system).

FIG. 1 shows a diagram of an example wireless communication network 100. According to some aspects, the wireless communication network 100 can be an example of a wireless local area network (WLAN), such as a Wi-Fi network. For example, the wireless communication network 100 can be a network that implements at least one of the IEEE 802.11 wireless communication protocol standard series (such as defined by the IEEE 802.11-2020 specification or its amendments, including but not limited to 802.11ay, 802.11ax, 802.11az, 802.11ba, 802.11bd, 802.11be, 802.11bf, and 802.11bn). In some other examples, the wireless communication network 100 may be an example of a cellular radio access network (RAN), such as a 5G or 6G RAN that implements one or more cellular protocols, such as those specified in one or more 3GPP standards. In some other examples, the wireless communication network 100 may include a WLAN that operates in an interoperable or converged manner with one or more cellular RANs to provide greater or enhanced network coverage to wireless communication devices within the wireless communication network 100 or to enable such devices to connect to the core of the cellular network, such as to access network management capabilities and functionality provided by the cellular network core.

The wireless communication network 100 may include a plurality of wireless communication devices, including at least one wireless access point (AP) 102 and any number of wireless stations (STAs) 104. Although only one AP 102 is shown in FIG. 1 , the wireless communication network 100 may include a plurality of APs 102. AP 102 may be or represent various types of network entities, including but not limited to a home network AP, an enterprise-class AP, a single-band AP, a dual-band simultaneous (DBS) AP, a tri-band simultaneous (TBS) AP, a standalone AP, a non-standalone AP, a software-enabled AP (soft AP), and a multi-link AP (also referred to as an AP multi-link device (MLD)), as well as a cellular (such as 3GPP, 4G LTE, 5G, or 6G) base station or other cellular network node (such as a Node B, an evolved Node B (eNB), a gNB, a transmission reception point (TRP)) or another type of device or equipment included in a radio access network (RAN), including an open RAN. (O-RAN) network entity, such as a central unit (CU), distributed unit (DU), or radio unit (RU).

Each of the STAs 104 may also be referred to as a mobile station (MS), a mobile device, a mobile phone, a wireless phone, an access terminal (AT), a user equipment (UE), a subscriber station (SS), or a subscriber unit, among others. STA 104 may represent a variety of devices, such as, among others, a mobile phone, other handheld or wearable communication device, a lightweight notebook, laptop, tablet, laptop, Chromebook, an augmented reality (AR), virtual reality (VR), mixed reality (MR), or extended reality (XR) wireless headset or other peripheral device, wireless earbuds, other wearable devices, a display device (e.g., a television, computer monitor, or video game console), a video game controller, a navigation system, a music or other audio or stereo device, a remote control device, a printer, a kitchen appliance (including a smart refrigerator) or other household appliance, a keychain (e.g., for passive keyless entry and startup), a wireless headset ... keyless entry and start (PKES) systems), Internet of Things (IoT) devices, and vehicles.

A single AP 102 and a set of associated STAs 104 may be referred to as a basic service set (BSS), which is managed by the respective AP 102. FIG. 1 additionally shows an example coverage area 108 of the AP 102, which may represent a basic service area (BSA) of the wireless communication network 100. The BSS may be identified by the STAs 104 and other devices via a service set identifier (SSID) and a basic service set identifier (BSSID), which may be a medium access control (MAC) address of the AP 102. The AP 102 may periodically broadcast a beacon frame (“beacon”) including a BSSID to enable any STA 104 within the wireless range of the AP 102 to “associate” or reassociate with the AP 102 to establish or maintain a respective communication link 106 (hereinafter also referred to as a “Wi-Fi link”) with the AP 102. For example, the beacon may include an identification or indication of a primary channel used by the respective AP 102 and a timing synchronization function (TSF) for establishing or maintaining timing synchronization with the AP 102. The AP 102 may provide access to external networks to various STAs 104 in the wireless communication network 100 via respective communication links 106.

To establish a communication link 106 with an AP 102, each of the STAs 104 is configured to perform a passive or active scanning operation ("scan") on channels in one or more frequency bands (e.g., 2.4 GHz, 5 GHz, 6 GHz, 45 GHz, or 60 GHz bands). To perform a passive scan, the STA 104 listens for beacons transmitted by respective APs 102 at periodic time intervals, which are referred to as target beacon transmission times (TBTT). To perform an active scan, the STA 104 generates and sequentially transmits a probe request on each channel to be scanned, and listens for probe responses from the AP 102. Each STA 104 may identify, determine, determine, or select an AP 102 to associate with based on the scan information obtained through passive or active scanning, and perform authentication and association operations to establish a communication link 106 with the selected AP 102. The selected AP 102 assigns an association identifier (AID) to the STA 104 at the apex of the association operation, and the AP 102 tracks the STA 104 using the association identifier.

As wireless networks become more popular, a STA 104 may have the opportunity to select one of many BSSs within range of the STA 104, or to select from multiple APs 102 that together form an extended service set (ESS) including multiple connected BSSs. For example, the wireless communication network 100 may be connected to a wired or wireless distribution system that enables multiple APs 102 to be connected in such an ESS. Therefore, a STA 104 may be covered by more than one AP 102 and may associate with different APs 102 at different times for different transmissions. Additionally, after associating with an AP 102, the STA 104 may also periodically scan its surrounding environment to find a more suitable AP 102 with which to associate. For example, a STA 104 that is moving relative to its associated AP 102 may perform a “roaming” scan to find another AP 102 with more desirable network characteristics, such as a greater received signal strength indicator (RSSI) or reduced traffic load.

In some cases, STA 104 may form a network without AP 102 or other devices other than STA 104 itself. An example of such a network is an ad hoc network (or wireless ad hoc network). An ad hoc network may alternatively be referred to as a mesh network or a peer-to-peer (P2P) network. In some cases, an ad hoc network may be implemented within a larger network (such as wireless communication network 100). In such an example, while STA 104 may be able to communicate with each other through AP 102 using communication link 106, STA 104 may also communicate directly with each other via direct wireless communication link 110. Additionally, two STAs 104 may communicate via a direct communication link 110, regardless of whether the two STAs 104 are associated with and served by the same AP 102. In such an ad hoc system, one or more of the STAs 104 may assume the role played by the AP 102 in the BSS. Such a STA 104 may be referred to as a group owner (GO) and may coordinate transmissions within the ad hoc network. Examples of direct wireless communication links 110 include Wi-Fi direct connections, connections established using a Wi-Fi Tunneled Direct Link Setup (TDLS) link, and other P2P group connections.

In some networks, the AP 102 or the STA 104, or both, may support applications associated with high throughput or low latency requirements, or may provide lossless audio to one or more other devices. For example, the AP 102 or the STA 104 may support applications and use cases associated with ultra-low-latency (ULL), such as ULL gaming, or streaming lossless audio and video to one or more personal audio devices (e.g., peripherals) or AR/VR/MR/XR headsets. In scenarios where a user uses two or more peripherals, the AP 102 or the STA 104 may support an extended personal audio network that facilitates communication with the two or more peripherals. Additionally, AP 102 and STA 104 may support additional ULL applications, such as cloud-based applications with ULL and high throughput requirements (e.g., VR cloud gaming).

As indicated above, in some implementations, the AP 102 and the STA 104 may operate and communicate (via respective communication links 106) in accordance with one or more of the IEEE 802.11 family of wireless communication protocol standards. These standards define WLAN radio and baseband protocols at the physical (PHY) and MAC layers. The AP 102 and the STA 104 transmit and receive wireless communications (hereinafter also referred to as "Wi-Fi communications" or "wireless packets") to each other in the form of PHY protocol data units (PPDUs).

Each PPDU is a composite structure that includes a PHY preamble and a payload in the form of a PHY Service Data Unit (PSDU). The information provided in the preamble can be used by a receiving device to decode subsequent data in the PSDU. In instances where the PPDU is transmitted over a combined or broadband channel, the preamble field may be replicated and transmitted in each of multiple component channels. The PHY preamble may include a traditional portion (or "legacy preamble") and a non-legacy portion (or "non-legacy preamble"). The traditional preamble may be used for packet detection, automatic gain control, and channel assessment, among other purposes. The traditional preamble may also generally be used to maintain compatibility with legacy devices. The format of the information in the non-legacy portion of the preamble, the encoding of the information, and the association of the information with the specific IEEE 802.11 wireless communication protocol to be used to transmit the payload are provided.

The AP 102 and STA 104 in the WLAN 100 may transmit PPDUs over an unlicensed spectrum, which may be a portion of the spectrum that includes bands traditionally used by Wi-Fi technology, such as the 2.4 GHz, 5 GHz, 6 GHz, 45 GHz, and 60 GHz bands. Some examples of the AP 102 and STA 104 described herein may also communicate in other bands that may support both licensed and unlicensed communications. For example, the AP 102 or the STA 104, or both, may also be able to communicate over a licensed band, where multiple operators may have separate licenses to operate in the same or overlapping frequency ranges. Such licensed operating bands may be mapped to or associated with the frequency range names FR1 (410 MHz to 7.125 GHz), FR2 (24.25 GHz to 52.6 GHz), FR3 (7.125 GHz to 24.25 GHz), FR4a or FR4-1 (52.6 GHz to 71 GHz), FR4 (52.6 GHz to 114.25 GHz), and FR5 (114.25 GHz to 300 GHz).

Each of the frequency bands may include multiple sub-bands and frequency channels (also referred to as sub-channels). For example, PPDUs compliant with IEEE 802.11n, 802.11ac, 802.11ax, 802.11be, and 802.11bn standard amendments may be transmitted over one or more of the 2.4 GHz, 5 GHz, or 6 GHz frequency bands, each of which is divided into multiple 20 MHz channels. Thus, these PPDUs are transmitted over physical channels with a minimum bandwidth of 20 MHz, but larger channels may be formed through channel bundling. For example, the PPDU may be transmitted over a physical channel having a bandwidth of 40 MHz, 80 MHz, 160 MHz, 240 MHz, 320 MHz, 480 MHz, or 640 MHz by bonding multiple 20 MHz channels together.

In some examples, the AP 102 or STA 104 of the WLAN 100 may implement Extremely High Throughput (EHT) or other features of current and future generations of the IEEE 802.11 wireless communication protocol standard series (such as IEEE 802.11be and IEEE 802.11bn standard amendments) to provide additional capabilities over other previous systems (e.g., high efficiency (HE) systems or other legacy systems). For example, the IEEE 802.11be standard amendment introduced 320 MHz channels, which are twice as wide as those channels that may be used with the IEEE 802.11ax standard amendment. Thus, the AP 102 or STA 104 may use a 320 MHz channel that doubles throughput and network capacity, and provides rate-to-range gains at high data rates due to a linear bandwidth-to-log SNR tradeoff. EHT and newer wireless communication protocols (such as those referred to as or associated with the IEEE 802.11bn standard amendment) may support flexible operating bandwidth enhancements, such as widened operating bandwidths relative to traditional operating bandwidths or more granular operations relative to traditional operations. For example, an EHT system may allow communications across operating bandwidths of 20 MHz, 40 MHz, 80 MHz, 160 MHz, 240 MHz, and 320 MHz. The EHT system can support multiple bandwidth modes, such as continuous 240 MHz bandwidth mode, continuous 320 MHz bandwidth mode, non-continuous 160+160 MHz bandwidth mode, or non-continuous 80+80+80+80 (or "4x80") MHz bandwidth mode.

In some examples where a wireless communication device (such as AP 102 or STA 104) operates in a continuous 320 MHz bandwidth mode or a 160+160 MHz bandwidth mode, signals for transmission may be generated by two different transmission chains of the wireless communication device, each having or associated with a 160 MHz bandwidth (and each coupled to a different power amplifier). In some other examples, the two transmission chains may be used to support a 240 MHz/160+80 MHz bandwidth mode by dropping the 320 MHz/160+160 MHz bandwidth mode with one or more 80 MHz sub-channels. For example, the signal for transmission may be generated by two different transmission links of the wireless communication device, each having a bandwidth of 160 MHz, wherein one of the transmission links outputs a signal having a redundant 80 MHz subchannel deleted therein. In some other examples where the wireless communication device may operate in a continuous 240 MHz bandwidth mode or a non-continuous 160+80 MHz bandwidth mode, the signal for transmission may be generated by three different transmission links of the wireless communication device, each having a bandwidth of 80 MHz. In some other examples, the signal for transmission may be generated by four or more different transmission links of the wireless communication device, each having a bandwidth of 80 MHz.

In non-contiguous examples, the operating bandwidth may span one or more distinct sets of subchannels. For example, a 320 MHz bandwidth may be contiguous and in the same 6 GHz band, or non-contiguous and in different bands or different regions within a band (e.g., partly in the 5 GHz band and partly in the 6 GHz band).

In some examples, the AP 102 or STA 104 may benefit from operability enhancements associated with EHT and newer generations of the IEEE 802.11 wireless communication protocol standard family. For example, an AP 102 or STA 104 attempting to gain access to the wireless medium of the WLAN 100 may implement techniques such as EHT-enhanced clear channel assessment (CCA) operations (which may include modifications to existing rules, structures, or messaging for legacy system implementations), such as increased bandwidth, deduplication, or improvements to carrier sensing and signal reporting mechanisms.

Access to the shared wireless medium is typically managed by a distributed coordination function (DCF). With DCF, there is typically no centralized master device that allocates time and frequency resources for the shared wireless medium. Instead, a wireless communication device (such as AP 102 or STA 104) may wait for a certain time and then compete for access to the wireless medium before being allowed to transmit data. DCF is implemented using time intervals including slot time (or "slot interval") and inter-frame space (IFS). IFS provides priority access to control frames for proper network operation. Transmissions may start at slot boundaries. There are different variations of IFS, including short IFS (SIFS), distributed IFS (DIFS), extended IFS (EIFS), and arbitration IFS (AIFS). The values of slot time and IFS may be provided by appropriate standard specifications, such as one or more of the IEEE 802.11 family of wireless communication protocol standards.

In some examples, a wireless communication device (such as AP 102 or STA 104) can implement DCF through the use of carrier sense multiple access (CSMA) with collision avoidance (CA) (CSMA/CA) techniques. According to such techniques, before transmitting data, the wireless communication device can perform idle channel assessment (CCA) and can determine (e.g., identify, detect, determine, calculate, or compute) that an associated wireless channel is idle. CCA includes physical (PHY layer level) carrier sensing and virtual (MAC layer level) carrier sensing. Physical carrier detection is accomplished by measuring the received signal strength of a valid frame and then comparing it to a threshold to determine (e.g., identify, detect, determine, calculate, or compute) whether the channel is busy. For example, if the received signal strength of the detected preamble is above the threshold, the medium is considered busy. Physical carrier detection 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 detected total energy is above the threshold, the medium is considered busy.

Virtual carrier detection is achieved through the use of a network allocation vector (NAV), which effectively acts as the duration that elapses before the wireless communication device can contend for access, even if the detected symbol is not present or even if the detected energy is below an associated threshold. The NAV is reset each time a valid frame is received that is not addressed to the wireless communication device. When the NAV reaches 0, the wireless communication device performs physical carrier detection. If the channel remains idle for an appropriate IFS, the wireless communication device starts a back-off timer, which represents the duration of time it hears the medium as idle before allowing the device to transmit. If the channel remains idle until the backoff timer expires, the wireless communication device becomes the holder (or "owner") of a transmission opportunity (TXOP) and can begin transmitting. A TXOP is the duration for which a wireless communication device can transmit frames over a channel after it has "won" contention for the wireless medium. The TXOP duration may be indicated in the U-SIG field of the PPDU. On the other hand, if one or more of the carrier detection mechanisms indicate that the channel is busy, the MAC controller within the wireless communication device will not allow transmission.

Each time the wireless communication device generates a new PPDU for transmission in a new TXOP, it randomly selects a new backoff timer duration. The available distribution of numbers that can be randomly selected for the backoff timer is called the contention window (CW). There are different CW and TXOP durations for each of the four access categories (ACs): voice (AC_VO), video (AC_VI), background (AC_BK), and best effort (AC_BE). This allows specific types of traffic to be prioritized in the network.

In some other examples, wireless communication devices (e.g., AP 102 or STA 104) may compete for access to the wireless medium of WLAN 100 according to an enhanced distributed channel access (EDCA) procedure. A random channel access mechanism such as EDCA may provide high priority traffic with a greater likelihood of obtaining medium access than low priority traffic. Wireless communication devices using EDCA may classify data into different access categories. Each AC may be associated with a different priority level and may be assigned a different random backoff (RBO) range, making it more likely that higher priority data will win a TXOP than lower priority data (e.g., by assigning a lower RBO to be higher, the likelihood that low latency data traffic will gain access to the shared wireless medium during a given contention period is increased. Unpredictable results of media access contention operations may prevent low latency applications from achieving a specific throughput level or meeting a specific latency requirement. Overview of Channel Numbering

The primary channel generally refers to the channel that the STA monitors for contention-based channel access. As described above with reference to FIG. 2 , in a WLAN supporting relatively large bandwidth, a 20 MHz channel may be designated as the primary channel. This channel may be referred to as primary channel 20, or as indicated in FIG. 2 , abbreviated as P20.

The selection of the bandwidth of the P20 channel generally determines all other channels. For example, in the case of a 160 MHz operating bandwidth, the selection of P20 may determine the secondary 20 MHz channel (S20), the primary 40 MHz channel (P40), the secondary 40 MHz channel (S40), the primary 80 MHz channel (P80), and the secondary 80 MHz channel (S80).

Figures 3A and 3B show examples of primary and secondary channel selection for a given channel. Graph 300 of Figure 3A shows how the bandwidth of 160 MHz channel number 163 can be allocated to form different 80 MHz channels (155 and 171), 40 MHz channels (151, 159, 167, and 175), and 20 MHz channels (149, 153, 157, 161, 165, 169, 173, 177). The specific channel frequencies of these channels can be determined based on a set of equations, determined by the operating bandwidth and the channel selection parameter X.

Table 350 of FIG. 3B shows possible combinations of channel frequencies for P20, S20, P40, S40, P80, and S80 channels for the 160 MHz bandwidth channel 163 shown in FIG. 3A. As shown, selecting parameter X is essentially the same as picking the channel frequency for P20. For example, picking X = 1 means that P20 is 153 and vice versa, resulting in S20 = 149, P40 = 151), S40 = 159, P80 = 155, and S80 = 171. Overview of Multiple Primary Channels

As mentioned above, in some WLAN scenarios, STAs may be able to monitor additional 20 MHz channels within the operating bandwidth to compete for channel access. In such scenarios, the initial primary channel is called the primary primary channel (M-primary channel or M-P20), and the additional 20 MHz channels/sub-channels are called opportunity primary channels (O-primary channels or O-P20).

4 shows an example diagram 400 of channel access for an AP and a STA (STA1) using sequential monitoring of multiple primary channels. As shown, using sequential monitoring, when the M-primary channel is found to be busy (as indicated by detecting a transmission 402 in the OBSS), the device can switch to the O-primary channel to contend for access.

The device may detect that the M-primary channel is busy by decoding the PPDU and determining that the PPDU is an OBSS PPDU. The device may also store the OBSS network allocation vector (NAV) indicated by the duration field in the OBSS PPDU to determine when to switch back to the M-primary channel.

In some cases, the AP may send an RTS frame 404 to cause STA1 to switch to the O-primary channel. STA1 may respond with a CTS frame 406 to confirm that STA1 has switched to the O-primary channel. As shown, the device may switch its primary radio back to the M-primary channel before the OBSS NAV expires (e.g., after a data transmission confirmed by ACK 408).

As shown in Figure 5, using parallel monitoring, the device can monitor each 20 MHz channel simultaneously. For example, a STA may have an auxiliary (AUX) radio that can be used for parallel monitoring. In the illustrated example, the AP sees the OBSS PPDU 502 on the M-primary channel and switches its primary radio to the O-primary channel and starts a TXOP. Although STA1 does not see the OBSS PPDU 502 on the M-primary channel, it can still monitor the O-primary channel via its AUX radio. Therefore, it can detect the RTS frame from the AP and switch to the O-primary channel accordingly. States related to TXOP duration determination for the O- primary channel

As described above, one potential challenge with using multi-primary channel access is how to determine the transmission opportunity (TXOP) duration when a wireless node using multiple channels for channel access has an asymmetric view of one or more of the channels.

The concept of asymmetric channel view can be understood with reference to the diagram 600 of FIG6. As shown, the AP can detect a first OBSS transmission 602 on a primary channel (e.g., M-primary channel) and switch to a non-primary channel (e.g., O-primary channel). Similarly, the STA detects a second OBSS transmission 604 on the primary channel and switches to the non-primary channel.

As shown, the first OBSS transmission 602 may end sooner than the OBSS transmission 604. As a result, the AP and the STA may have different determined TXOP durations that apply when they switch to the non-primary channel to communicate. In the example shown, the STA has data to transmit (as shown by the solid line). Due to the different views of the primary channel, the AP's TXOP duration may expire sooner than the STA's TXOP duration, and the AP may therefore return to the primary channel before the data transmission 606 from the STA is completed.

Therefore, in this example, if the receiver/AP terminates PPDU reception prematurely and switches back to the M-primary channel, performance loss may occur on the O-primary channel. This performance loss reduces the potential gain of the multi-primary channel feature.

However, aspects of the present disclosure provide a mechanism by which a transmitter and a receiver can effectively negotiate the TXOP duration allowed for the O-primary channel. As will be described in more detail below, a transmitter and a receiver can exchange information about the TXOP duration allowed on the O-primary channel. In some cases, the NAV of the O-primary channel can be set after this exchange of information is completed. As a result, the transmitter and the receiver can reach an agreement on the TXOP duration when to switch to the O-primary channel.

TXOP determination according to aspects of the present disclosure may be understood with reference to the example call flow diagram 700 of FIG. 7 .

In some aspects, one of the wireless nodes and OBSS AP shown in FIG7 can be an instance of AP 102 (e.g., AP STA) depicted and described with respect to FIG1. In some aspects, one of the wireless nodes shown in FIG7 can be an instance of (non-AP) STA 104 depicted and described with respect to FIG1.

As indicated at 702, a first wireless node (eg, an AP or a STA) may detect an OBSS transmission on a first primary channel (eg, an M-primary channel).

The first wireless node may then transmit a first frame to the second wireless node, the first frame indicating a requested TXOP duration determined based on the detected OBSS transmission.

After receiving the first frame, the second wireless node may determine an allowed TXOP duration, as indicated at 704. The second wireless node may then transmit a second frame indicating the allowed TXOP duration.

As indicated at 706 and 708, the first and second wireless nodes may then communicate with each other according to the allowed TXOP duration.

8 and 9 illustrate examples of TXOP duration determination based on exchanging information between a transmitter and a receiver regarding an allowed TXOP duration on an O-primary channel according to aspects of the present disclosure.

Referring first to the diagram 800 of Figure 8, the illustrated example assumes that the transmitter is a STA and the receiver is an AP. Since the STA has the amount of data to transmit, it can be considered a transmitter in this context and therefore knows the corresponding TXOP duration to be requested for the data transmission.

After detecting an OBSS transmission on the primary channel (M-primary channel), the transmitter and receiver switch to a non-primary channel (O-primary channel) to exchange information regarding the allowed TXOP duration on the O-primary channel. In the illustrated example, the receiver (AP) detects OBSS transmission 802 and the transmitter (STA) detects OBSS transmission 804.

The exchange of information may involve any suitable type of frame. As illustrated, according to certain aspects, the exchange of information regarding the TXOP duration allowed on the O-primary channel may occur in an initial control frame (ICF) on the O-primary channel. An ICF generally refers to a frame sent to acknowledge that a peer STA has switched to the O-primary channel. Depending on the capabilities of the peer, the ICF may also be designed to cause the STA's primary radio to switch to the O-primary channel if the STA's primary radio has not already switched (e.g., if it has not detected the OBSS).

Once the exchange of the ICF (and its response from the AP) is complete, the NAV on the O-primary channel may be set. In some cases, the response from the AP may indicate the allowed TXOP duration for the O-primary channel, and the NAV is set based on the allowed TXOP duration.

According to certain aspects, the exchange of TXOP duration information can occur after the ICF frame exchange is completed. More generally, TXOP duration negotiation can occur in any short frame exchange (such as RTS/CTS, MU-RTS, BSRP/BSR, BAR/BA, MU-BAR/BA) and can even occur on the M-Primary channel.

As shown in FIG8 , the allowed TXOP duration may be significantly shorter than the TXOP duration requested by the STA. In such cases, the STA may adjust the duration of the PPDU or TXOP or both accordingly. This approach may prevent undue suppression of competition for access to the medium by other wireless nodes.

In some cases, the PPDU size may not need to be adjusted. For example, if the requested TXOP duration is based on a sequence of n PPDUs ("PPDU1 -- ACK1 -- PPDU2 -- ACK2 -- .. -- PPDU-N -- ACK-n"), after receiving the allowed duration from the receiver, the transmitter can simply adjust the number of PPDUs (e.g., by limiting the sequence to "PPDU1 -- ACK1 -- PPDU2 -- ACK2 -- .. -- PPDU-m -- ACK-m", where m < n).

In some cases, the allowed TXOP duration on the O-primary channel may be determined as the minimum of the TXOP duration requested by the transmitter and the TXOP duration allowed at the receiver: TXOP _{O- primary channel} = min (TXOP requested by TX, TXOP allowed at RX).

In this context, the TXOP requested by the transmitter can be the minimum duration required to transmit the amount of data (e.g., to flush a number of PPDUs) and the TXOP duration allowed by the transmitter: TXOP requested by TX = min(time required to flush PPDUs, TXOP allowed by TX).

The TXOP duration allowed at the transmitter and receiver may depend on the OBSS transmissions they detect (804 and 802).

For example, the TXOP duration allowed at the transmitter may be equal to the remaining duration of the OBSS transmission 802 as seen by the transmitter on the M-primary channel. The TXOP allowed at the receiver may be equal to the remaining NAV of the OBSS STA as seen by the receiver on the M-primary channel (based on the OBSS transmission 804). The duration of the OBSS transmission (802/804) may be based on (i) the value indicated in the Duration field of the frame received from the OBSS STA (which is the NAV), or (ii) the value indicated in the Length subfield of the L-SIG field of the PPDU received from the OBSS STA.

As will be described in more detail below, if there is more than one receiver (e.g., if the transmitter is an AP transmitting to multiple STAs), the allowed TXOP duration on the O-primary channel may be considered to be based on the minimum of the allowed TXOP durations of all receivers.

As shown in FIG8 , after receiving an ACK 808 for its PPDU 806, the STA may switch back to the M-primary channel. In some cases, the transmitter may switch after receiving an ACK for the final PPDU. In the case of transmitting a sequence of PPDUs (e.g., via a SIFS burst), all PPDUs and ACKs may need to be completed within the allowed TXOP duration. In some cases, PPDU transmissions may be adjusted to account for the transition delay required to switch the radio from the O-primary channel to the M-primary channel.

As mentioned above, the TXOP duration requested by the transmitter can be indicated using an ICF on the O-primary channel. The ICF can be a type of trigger frame such as a multi-user (MU) request to send (MU-RTS), a buffer status report poll (BSRP), or a MU block acknowledgement request (MU-BAR).

In some cases, the duration field of the ICF may be set to a relatively small value. The value in this field is used by neighbor STAs to set their NAV values. As shown in FIG8 , the duration value may protect only the response frames (e.g., the marked CTS frame and applicable SIFS). One benefit of this approach is that neighbor STAs will not unnecessarily set their NAVs to large values if the requested TXOP is not permissible at the receiver (resulting in a smaller allowed TXOP duration).

The TXOP requested by the transmitter may be indicated in a field inside the ICF. For example, the "UL Length" field in the common information field of the trigger frame may be used to specify the requested TXOP duration. Alternatively, the "Allocated Duration" field in the common information field of the trigger frame may be used to specify the requested TXOP duration. In some cases, a newly defined subfield in the common information or user information field of the trigger frame or an A-Control field defined for the trigger frame may be used to specify the requested TXOP duration.

As indicated above, the transmitter may calculate the value of the requested TXOP duration based on the remaining duration of the OBSS transmission and/or how much data is in its queue. For example, if the remaining duration of the OBSS is greater than the time to clear the transmitter PPDU, the requested TXOP duration may be set to the time to clear the transmitter PPDU. On the other hand, if the remaining duration of the OBSS is less than the time to clear the transmitter PPDU, the requested TXOP duration may be set to the remaining duration of the OBSS.

Aspects of the present disclosure may be used in both single user (SU) and multi-user (MU) scenarios.

In a SU scenario, meaning that the transmitter is initiating a TXOP to communicate with only one STA (e.g., UL or DL SU TXOP), the allowed TXOP duration may be indicated in the "Duration" field of the frame sent in response to the ICF. Neighboring STAs on the O-Primary channel shall set their NAVs based on this value.

In MU scenarios, meaning that the transmitter is initiating a TXOP to communicate with more than one STA (e.g., AP initiated DL MU TXOP), the "Duration" field of the frame sent in response to the ICF is set to a small value. This value can be calculated, for example: Duration(Response) = Duration(ICF) – SIFS – Time taken to transmit the response.

As an alternative, the value may be set to protect the subsequent SIFS. As mentioned above, one benefit of this approach is that a neighboring STA will not unnecessarily set its NAV to a large value if the allowed TXOP at some other STA is not large enough.

In some cases, the TXOP allowed by the receiver may be indicated in a field inside the response frame. For example, the TXOP allowed by the receiver may be indicated in an A-Control field included in the response frame.

Certain calculations may be common to both MU and SU scenarios. For example, the receiver may calculate the allowed TXOP duration based on the remaining OBSS duration it sees (e.g., OBSS NAV) and the TXOP duration requested by the transmitter. For example, if the remaining OBSS duration is greater than the TXOP duration requested by the transmitter, the allowed TXOP duration may be equal to the TXOP duration requested by the transmitter. On the other hand, if the remaining OBSS duration is less than the TXOP duration requested by the transmitter, the allowed TXOP duration may be equal to the remaining OBSS duration.

Referring again to FIG. 8 , the transmitter (STA in this example) may limit the TXOP duration on the O-primary channel to the allowed TXOP duration (eg, the value indicated by the receiver in the Duration field of the frame sent in response to the ICF).

In the MU scenario described in more detail below with reference to FIG. 9 , the transmitter may discard one or more receivers (eg, STA1 or STA2) from subsequent frames if their allowed TXOP duration is less than the transmitter's preferred TXOP duration.

In general, the transmitter may calculate the allowed TXOP duration as the minimum value of the TXOP allowed by the receiver served in the subsequent frame. In the SU case, the duration value set in the subsequent frame may follow the baseline behavior. In the MU case, the duration value of the first frame sent after receiving the response frame may be set according to the allowed TXOP indicated by the receiver. If the transmitter is a STA, it may switch back to the M-primary channel after the TXOP ends.

Referring to diagram 900 of FIG. 9 , the illustrated example assumes that the transmitter is an AP and the plurality of STAs are receivers.

After detecting an OBSS transmission on the primary channel (M-primary channel), the transmitter and receiver switch to a non-primary channel (O-primary channel) to exchange information about the TXOP duration allowed on the O-primary channel. In the illustrated example, the AP detects OBSS transmission 904, STA1 detects OBSS transmission 902, and STA2 detects OBSS transmission 912.

9, when the transmitter is an AP, it may switch back to the M-primary channel after the TXOP ends (after receiving ACK 908 from STA1 and/or ACK 918 from STA2). Alternatively, the AP may initiate a TXOP with another STA after the TXOP ends.

In some cases, the type of TXOP duration decision for the O-primary channel may be limited to either the SU case or the MU case. For example, it may be possible to define only the MU case, and in such cases, the MU case may be reused for the SU case (e.g., where the number of receivers = 1). As another example, only the SU case may be defined.

MU scenarios are often applicable for DL TXOPs. In such scenarios, if the non-AP STA remains on the O-primary channel beyond the OBSS NAV seen on the M-primary channel, there are no compatibility issues with other (legacy) devices, because the non-AP STA may not communicate (e.g., exchange data frames) with STAs outside the associated AP. However, after switching back to the M-primary channel, (multiple) STAs may need to perform some form of media synchronization recovery on the M-primary channel. In some scenarios, if the non-AP STA participates in frame exchanges with other non-AP STAs (e.g., in P2P frame exchanges), the non-AP STA may indicate to the AP that it cannot extend the frame exchange on the O-primary channel beyond the TXOP of the OBSS STA on the M-primary channel.

As described above, one potential benefit of the proposed mechanism is that the duration of the O-primary channel TXOP can be determined without overly suppressing neighboring STAs (e.g., by not setting their NAVs beyond the actual use of the channel), because the NAV is generally set by the transmitter and/or receiver only after the duration of the allowed TXOP carried in a field inside a request and response frame (such as an ICF) is exchanged between the transmitter and the receiver.

However, other options of the proposed solution are possible which may have different effects on the suppression of neighboring STAs.

For example, according to the first option, the transmitter may indicate the requested TXOP duration in the "Duration" field. The receiver may indicate the allowed TXOP duration in the "Duration" field, and the transmitter may adjust the TXOP duration on the O-primary channel based on the value indicated by the receiver. This option has the potential to cause over-throttling if the OBSS NAV seen at the transmitter is greater than the OBSS NAV seen at the receiver.

According to the second option, the transmitter may set a short NAV but may not indicate a requested TXOP duration. The receiver may set the allowed TXOP duration in the "Duration" field, and the transmitter may start a TXOP according to this indicated allowed TXOP duration. This option also has the potential to cause over-throttling, for example, if the transmitter does not have enough PPDUs in its queue to utilize the entire allowed TXOP duration.

Although some examples of applying the techniques proposed herein are in the context of multi-primary channel access and on an O-primary channel, in general, the TXOP duration negotiation mechanism proposed herein can also be widely applied to other use cases.

One example is that the receiver may have some in-device coexistence considerations, such as the receiver needs to release its antenna/resources from other wireless (e.g., 802.11) transmissions for an upcoming Bluetooth transmission. In such a case, the receiver may want to terminate the TXOP faster than the transmitter requested. In this scenario, the negotiation procedure proposed herein may be applicable. In other words, the negotiation may be performed on the M-primary channel for various reasons, such as in-device coexistence. In fact, in some cases, the transmitter and receiver performing the negotiation may not even support multi-primary channel access.

FIG. 10 is a flow chart illustrating an example process 1000 that may be performed at a first wireless node according to some aspects of the present disclosure. The operations of process 1000 may be performed by a wireless AP or a wireless STA or components thereof as described herein. For example, process 1000 may be performed by a wireless communication device operating as or within a wireless AP or a wireless STA, such as the wireless communication device 1200 described with reference to FIG. 12 . In some examples, process 1000 may be performed by a wireless AP or a wireless STA, such as one of the APs 102 or one of the wireless STAs 104 described with reference to FIG. 1 .

Process 1000 begins at step 1005, where communication is switched from a first primary channel to a second primary channel after (eg, based on) detecting an overlapping basic service set (BSS).

Process 1000 then proceeds to step 1010 where a first frame for transmission on a second primary channel is output, the first frame indicating a requested duration of a transmission opportunity (TXOP) associated with the second primary channel.

Process 1000 then proceeds to step 1015 where, after outputting (eg, in response to) the first frame, an indication of an allowed duration of the TXOP is obtained.

Process 1000 then proceeds to step 1020, where the at least one second wireless node is communicated with according to the allowed duration of the TXOP.

In one aspect, process 1000 or any aspects related thereto may be performed by an apparatus, such as wireless communication device 1200 of FIG. 12 , which includes various components operable, configured, or adapted to perform process 1000. Wireless communication device 1200 is described in greater detail below.

It should be noted that FIG. 10 is merely one example of a method, and other methods including fewer, additional, or alternative steps are possible consistent with the present disclosure.

FIG. 11 is a flow chart illustrating an example process 1100 that may be performed at a second wireless node according to some aspects of the present disclosure. The operations of process 1100 may be performed by a wireless AP or a wireless STA or components thereof as described herein. For example, process 1100 may be performed by a wireless communication device operating as or within a wireless AP or a wireless STA, such as the wireless communication device 1200 described with reference to FIG. 12 . In some examples, process 1100 may be performed by a wireless AP or a wireless STA, such as one of the APs 102 or one of the wireless STAs 104 described with reference to FIG. 1 .

Process 1100 begins at step 1105, where communication via a first primary channel is switched to communication via a second primary channel after (eg, based on) detecting an overlapping basic service set (BSS).

Process 1100 then proceeds to step 1110 where a first frame is obtained on a second primary channel, the first frame indicating a requested duration of a transmission opportunity (TXOP) associated with the second primary channel.

Process 1100 then proceeds to step 1115 where an indication of the allowed duration of the TXOP transmitted after acquiring the first frame is output.

Process 1100 then proceeds to step 1120 where communication is performed with at least one first wireless node according to the allowed duration of the TXOP.

In one aspect, the process 1100 or any aspects related thereto may be performed by an apparatus, such as the wireless communication device 1200 of FIG. 12 , which includes various components operable, configured, or adapted to perform the process 1100. The wireless communication device 1200 is described in more detail below.

It should be noted that FIG. 11 is merely one example of a method, and other methods including fewer, additional, or alternative steps are possible consistent with the present disclosure.

FIG12 shows a block diagram of an example wireless communication device 1200 according to some aspects of the present disclosure. In one example, the wireless communication device 1200 is configured or operable to perform the process 1000 described with reference to FIG10 and/or the process 1100 described with reference to FIG11. In various embodiments, the wireless communication device 1200 may be a chip, SoC, chipset, package, or device, which may include: one or more modems (such as a Wi-Fi (IEEE 802.11) modem or a cellular modem, such as a 3GPP 4G LTE, or 5G compatible modem); one or more processors, processing blocks, or processing elements (collectively referred to as "processors"); one or more radio devices (collectively referred to as "radio devices"); and one or more memories or memory blocks (collectively referred to as "memories").

In some examples, the wireless communication device 1200 may be a device for use in an AP, such as the AP 102 described with reference to FIG. 1 . In some examples, the wireless communication device 1200 may be a device for use in a STA, such as the STA 104 described with reference to FIG. 1 . In some other examples, the wireless communication device 1200 may be an AP or STA including such a chip, SoC, chipset, package, or device, and multiple antennas. The wireless communication device 1200 is capable of transmitting and receiving wireless communications in the form of, for example, wireless packets. For example, the wireless communication device may be configured or operable to transmit and receive packets in the form of physical layer PPDUs and MPDUs that conform to one or more of the IEEE 802.11 wireless communication protocol standard family. In some embodiments, the wireless communication device 1200 also includes or may be coupled to an application processor, which may be further coupled to another memory. In some embodiments, the wireless communication device 1200 further includes at least one external network interface that facilitates communication with a core network or a backhaul network to obtain access to an external network including the Internet.

The wireless communication device 1200 includes at least a switching component 1202, an acquisition component 1204, an output component 1206, a communication component 1208, an adjustment component 1210, a calculation component 1212, an initiation component 1214, and an indication component 1216. Portions of one or more of the components 1202, 1204, 1206, 1208, 1210, 1212, 1214, and/or 1216 may be at least partially implemented in hardware or firmware. For example, the acquisition component 1202 may be at least partially implemented by a modem. In some examples, at least some of the components 1202, 1204, 1206, 1208, 1210, 1212, 1214, and/or 1216 are at least partially implemented by a processor and implemented as software stored in memory. For example, portions of one or more of the components 1202, 1204, 1206, 1208, 1210, 1212, 1214, and/or 1216 may be implemented as non-transitory instructions (or "code") that can be executed by a processor to perform the functions or operations of the respective modules.

In some embodiments, a processor may be a component of a processing system. A processing system may generally refer to a system or series of machines or components that receives input and processes the input to produce a set of outputs (which may be transmitted to other systems or, for example, components of the wireless communication device 1200). For example, a processing system of the wireless communication device 1200 may refer to a system that includes various other components or subcomponents of the wireless communication device 1200, such as a processor, or a transceiver, or a communication manager, or other components or combinations of components of the wireless communication device 1200. The processing system of the wireless communication device 1200 may interface with other components of the wireless communication device 1200 and may process information (such as input or signals) received from the other components or output information to the other components. For example, the chip or modem of the wireless communication device 1200 may include a processing system, a first interface for outputting information, and a second interface for obtaining information. In some embodiments, the first interface may refer to an interface between the processing system of the chip or modem and a transmitter, so that the wireless communication device 1200 can transmit information output from the chip or modem. In some embodiments, the second interface may refer to an interface between the processing system of the chip or modem and a receiver, so that the wireless communication device 1200 can obtain information or signal input, and the information can be transmitted to the processing system. A person having ordinary knowledge in the art will easily recognize that the first interface can also obtain information or signal input, and the second interface can also output information or signal output. Example terms

Examples of implementations are described in the following numbered clauses:

Item 1: A method for wireless communication at a first wireless node, comprising: upon detecting an overlapping basic service set (BSS), switching from communication via a first primary channel to communication via a second primary channel; outputting a first frame for transmission on the second primary channel, the first frame indicating a requested duration of a transmission opportunity (TXOP) associated with the second primary channel; after outputting the first frame, obtaining an indication of an allowed duration of the TXOP; and communicating with at least one second wireless node according to the allowed duration of the TXOP.

Clause 2: The method of clause 1, wherein: the first main channel comprises a primary main channel; and the at least one second main channel comprises a chance main channel.

Clause 3: The method of any one of clauses 1 to 2, wherein the communicating comprises: outputting at least one physical layer protocol data unit (PPDU) transmitted according to the allowed duration of the TXOP; and switching back from the second primary channel to the first primary channel after the TXOP ends.

Clause 4: The method of clause 3, further comprising adjusting at least one of a duration of the at least one PPDU or a duration of the TXOP based on the allowed duration of the TXOP

Clause 5: The method of any one of clauses 1 to 4, wherein the first frame comprises an initial control frame (ICF).

Clause 6: The method of any of clauses 1 to 5, further comprising calculating the requested duration based on at least one of: a duration of an overlapping BSS transmission, or an amount of data in a queue associated with the transmitter device.

Clause 7: A method as in any of clauses 1 to 6, wherein: the TXOP comprises a multi-user (MU) TXOP; and the allowed duration is based on at least one of the requested duration, a short inter-frame space (SIFS) associated with the second wireless node, or a time associated with the transmission of the indication.

Clause 8: The method of any one of clauses 1 to 7, wherein the first wireless node comprises an access point (AP) device.

Clause 9: The method of any one of clauses 1 to 8, further comprising initiating a second TXOP with a third wireless node after the allowed duration expires.

Clause 10: The method of any one of clauses 1 to 9, wherein the first wireless node comprises a non-access point (AP) STA device.

Clause 11: The method of any one of clauses 1 to 10, wherein the first frame comprises a trigger frame including at least one of an uplink length field, an allocated duration field, a duration field, or a subfield indicating the requested duration.

Clause 12: The method of any of clauses 1 to 11, wherein the allowed duration is indicated in at least one of: an uplink length field, an allocated duration field, a duration field, or a subfield of a second frame obtained in response to the first frame.

Item 13: A method for wireless communication at a second wireless node, comprising: switching from communication via a first primary channel to communication via a second primary channel after detecting an overlapping basic service set (BSS); obtaining a first frame on the second primary channel, the first frame indicating a requested duration of a transmission opportunity (TXOP) associated with the second primary channel; outputting an indication of an allowed duration of the TXOP transmitted after obtaining the first frame; and communicating with at least one first wireless node according to the allowed duration of the TXOP.

Item 14: The method of Item 13, wherein: the first main channel comprises a primary main channel; and the at least one second main channel comprises a chance main channel.

Clause 15: The method of any one of clauses 13 to 14, wherein the communicating comprises: obtaining at least one physical layer protocol data unit (PPDU) according to the allowed duration of the TXOP; and switching back from the second primary channel to the first primary channel after the TXOP ends.

Clause 16: The method of any one of clauses 13 to 15, further comprising adjusting a duration of the TXOP according to the allowed duration of the TXOP

Clause 17: The method of any one of clauses 13 to 16, wherein the first frame comprises an initial control frame (ICF).

Clause 18: The method of any one of clauses 13 to 17, further comprising calculating the allowed duration based on at least one of: a duration of an overlapping BSS transmission;

Clause 19: A method as in any of clauses 13 to 18, wherein: the TXOP comprises a multi-user (MU) TXOP; and the allowed duration is based on at least one of the requested duration, a short inter-frame space (SIFS) associated with the second wireless node, or a time associated with the transmission of the indication.

Clause 20: The method of any one of clauses 13 to 19, wherein the first wireless node comprises an access point (AP) device.

Clause 21: The method of any one of clauses 13 to 20, wherein the first wireless node comprises a non-access point (AP) STA device.

Item 22: The method of any one of items 13 to 21, wherein the first frame comprises a trigger frame, the trigger frame including at least one of an uplink length field, an allocated duration field, a duration field, or a subfield indicating the requested duration.

Clause 23: The method of any of clauses 13 to 22, wherein the allowed duration is indicated in at least one of: an uplink length field, an allocated duration field, a duration field, or a subfield of a second frame obtained in response to the first frame.

Item 24: A device comprising: at least one memory comprising executable instructions; and at least one processor configured to execute the executable instructions and cause the device to perform the method of any one of items 1 to 23.

Clause 25: An apparatus comprising means for performing the method of any one of clauses 1 to 23.

Item 26: A non-transitory computer-readable medium comprising executable instructions that, when executed by at least one processor of a device, cause the device to perform the method of any one of items 1 to 23.

Item 27: A computer program product embodied on a computer-readable storage medium, comprising code for executing the method of any one of items 1 to 23.

Item 28: A wireless node comprising: at least one transceiver; at least one memory comprising executable instructions; and at least one processor configured to execute the executable instructions and cause the wireless node to perform a method as described in any one of Items 1 to 12, wherein the at least one transceiver is configured to transmit the first frame.

Clause 29: A wireless node comprising: at least one transceiver; at least one memory comprising executable instructions; and at least one processor configured to execute the executable instructions and cause the wireless node to perform the method of any one of clauses 13 to 23, wherein the at least one transceiver is configured to transmit the first frame. Additional Considerations

As used herein, the term "determine" or "determining" encompasses a wide variety of actions, and thus, "determining" may include calculating, computing, processing, deriving, estimating, investigating, looking up (e.g., by looking up in a table, a database, or another data structure), inferring, ascertaining, or measuring, among other possibilities. Moreover, "determining" may include receiving (e.g., receiving information), accessing (e.g., accessing data stored in a memory), or transmitting (e.g., transmitting a message), among other possibilities. Additionally, "determining" may include resolving, selecting, obtaining, choosing, establishing, and other such similar actions.

As used herein, the phrase "at least one of" or "one or more of" in a list of items refers to any combination of those items, including a single component. As an example, "at least one of: a, b, or c" is intended to cover: a, b, c, a-b, a-c, b-c, and a-b-c. As used herein, "or" is intended to be interpreted as inclusive unless otherwise expressly indicated. For example, "a or b" may include only a, only b, or a combination of a and b. In addition, as used herein, a phrase referring to "a or an" element refers to one or more of such elements that act individually or collectively to perform the described function(s). Additionally, a "set" refers to one or more items, and a "subset" refers to a set that is smaller than the entire set but not empty.

As used herein, "a processor," "at least one processor," or "one or more processors" generally refers to a single processor configured to perform one or more operations, or multiple processors configured to collectively perform one or more operations. In the case of multiple processors, execution of the one or more operations may be divided among different processors, although one processor may perform multiple operations and multiple processors may collectively perform a single operation. Similarly, “a memory”, “at least one memory”, or “one or more memories” generally refers to a single memory configured to store data and/or instructions, or multiple memories configured to collectively store data and/or instructions.

The components for switching, the components for obtaining, the components for outputting, the components for communicating, the components for adjusting, the components for calculating, the components for initiating, and/or the components for indicating may include one or more processors, such as one or more of the processors described above with reference to Figure 12.

As used herein, "based on" is intended to be interpreted as inclusive, unless expressly indicated otherwise. For example, "based on" may be used interchangeably with "based at least in part on," "associated with," "in association with," or "in accordance with," unless expressly indicated otherwise. Specifically, unless the phrase refers to "based on only 'a'" or an equivalent in context, whether "based on 'a'" or "based at least in part on 'a'" may be based on 'a' alone, or based on a combination of 'a' and one or more other factors, conditions, or information.

The various illustrative components, logic, logic blocks, modules, circuits, operations, and algorithmic procedures described in conjunction with the examples 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. The interchangeability of hardware, firmware, and software is generally described in terms of functionality and is illustrated in the various illustrative components, blocks, modules, circuits, and procedures 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.

Various modifications of the examples described in this disclosure may be apparent to those skilled in the art, and the general principles defined herein may be applied to other examples without departing from the spirit or scope of this disclosure. Therefore, it is not intended that the scope of the patent application be limited to the examples shown herein, but rather to be consistent with the maximum scope consistent with this disclosure, the principles and novel features disclosed herein.

Additionally, various features described in this specification in the context of separate examples may also be implemented in combination in a single embodiment. Conversely, various features described in the context of a single embodiment may also be implemented separately in multiple embodiments, or in any suitable subcombination. Thus, while features may be described above as acting in a particular combination, and even initially claimed as such, one or more features from the claimed combination may be deleted from the combination in some cases, and the claimed combination may relate to subcombinations or variations of subcombinations.

Similarly, although operations are depicted in a particular order in the drawings, this should not be understood as requiring that such operations be performed in the particular order shown or in a sequential order, or that all depicted operations be performed, to achieve the desired result. Further, the drawings may schematically depict one or more example procedures in the form of a flowchart or flow diagram. However, other operations not depicted may be incorporated into the schematically depicted example procedures. For example, one or more additional operations may be performed before, after, simultaneously with, or between any of the depicted operations. In some cases, multitasking and parallel processing may be advantageous. Furthermore, the separation of various system components in the examples described above should not be understood as requiring such separation in all examples, and it should be understood that the described program components and systems may generally be integrated together in a single software product or packaged into multiple software products.

100: wireless communication network; WLAN 102: wireless access point (AP); AP 104: wireless station (STA); STA 106: communication link 108: coverage area 110: direct wireless communication link; direct communication link 149,153,157,161,165,169,173,177: 20 MHz channel 151,159,167, and 175: 40 MHz channel 155 and 171: 80 MHz channel 163: channel number; channel 200: figure 202: OBSS transmission 204: wideband bandwidth 206: transmission in BS 300: figure 350: table 400: figure 402: Transmission 404: RTS frame 406: CTS frame 408: ACK 502: OBSS PPDU 600: Figure 602: First OBSS transmission 604: Second OBSS transmission; OBSS transmission 606: Data transmission 700: Call flow chart 702: Step 704: Step 706: Step 708: Step 800: Figure 802: OBSS transmission 804: OBSS transmission 806: PPDU 808: ACK 900: Figure 902: OBSS transmission 904: OBSS transmission 908: ACK 912: OBSS transmission 918: ACK 1000: Procedure 1005: step 1010: step 1015: step 1020: step 1100: procedure 1105: step 1110: step 1115: step 1120: step 1200: wireless communication device 1202: switching component; component 1204: obtaining component; component 1206: output component; component 1208: communication component; component 1210: adjustment component; component 1212: calculation component; component 1214: starting component; component 1216: indication component; component AP: access point P20: 20 MHz main channel P40: main 40 MHz channel P80: Primary 80 MHz channel S20: Secondary 20 MHz channel S40: Secondary 40 MHz channel S80: Secondary 80 MHz channel STA: Station

The accompanying figures depict certain features of various aspects disclosed herein and should not be construed as limiting the scope of the present disclosure. [FIG. 1] shows a diagram of an example wireless communication network. [FIG. 2] shows a diagram of an example bandwidth configuration for a wireless local area network (WLAN). [FIG. 3A] and [FIG. 3B] show examples of primary and secondary channel selection for a given channel. [FIG. 4] and [FIG. 5] show examples of channel access using multiple primary channels that can utilize aspects of the present disclosure. [FIG. 6] shows an example of an asymmetric channel view that can be resolved according to aspects of the present disclosure. [FIG. 7] shows an example call flow diagram of a transmission opportunity (TXOP) duration determination according to aspects of the present disclosure. [FIG. 8] and [FIG. 9] illustrate examples of TXOP duration determination according to aspects of the present disclosure. [FIG. 10] illustrates a flow chart of an example process that can be executed at a first wireless node that supports TXOP duration determination associated with aspects of the present disclosure. [FIG. 11] illustrates a flow chart of an example process that can be executed at a second wireless node that supports TXOP duration determination associated with aspects of the present disclosure. [FIG. 12] illustrates a block diagram of an example wireless communication device that supports aspects of the present disclosure.

Similar component numbers and naming in the various drawings indicate similar components.

1000:Process

1005: Steps

1010: Steps

1015: Steps

1020: Steps

Claims (23)

A device for wireless communication, comprising: At least one memory including computer executable instructions; and One or more processors configured to execute the computer executable instructions and cause the device to: Switch from communication via a first primary channel to communication via a second primary channel at a first wireless node upon detection of an overlapping basic service set (BSS); Output a first frame for transmission on the second primary channel, the first frame indicating a requested duration of a transmission opportunity (TXOP) associated with the second primary channel; After outputting the first frame, obtain an indication of an allowed duration of the TXOP; and Communicate with at least one second wireless node according to the allowed duration of the TXOP. The device of claim 1, wherein: the first main channel comprises a primary main channel; and the second main channel comprises a chance main channel. The device of claim 1, wherein for communication, the one or more processors are further configured to cause the first device to: output at least one physical layer protocol data unit (PPDU) transmitted according to the allowed duration of the TXOP; and after the TXOP ends, switch back from the second primary channel to the first primary channel. The device of claim 3, wherein the one or more processors are further configured to cause the device to adjust at least one of a duration of the at least one PPDU or a duration of the TXOP based on the allowed duration of the TXOP. The device of claim 1, wherein the first frame comprises an initial control frame (ICF). The device of claim 1, wherein the one or more processors are further configured to cause the device to calculate the requested duration based on at least one of: a duration of an overlapping BSS transmission; or an amount of data in a queue associated with the first wireless node. The apparatus of claim 1, wherein: the TXOP comprises a multi-user (MU) TXOP; and the allowed duration is based on at least one of the requested duration, a short interframe space (SIFS) associated with the second wireless node, or a time associated with the indicated transmission. The device of claim 1, wherein the one or more processors are further configured to cause the device to initiate a second TXOP with a third wireless node after the allowed duration expires. The apparatus of claim 1, wherein the first frame comprises a trigger frame including at least one of an uplink length field, an allocated duration field, a duration field, or a subfield indicating the requested duration. The apparatus of claim 1, wherein the allowed duration is indicated in at least one of: an uplink length field, an allocated duration field, a duration field, or a subfield of a second frame obtained in response to the first frame. The device of claim 1, further comprising at least one transceiver configured to transmit the first frame, wherein the device is configured as a wireless station or an access point (AP). A device for wireless communication, comprising: At least one memory including computer executable instructions; and One or more processors configured to execute the computer executable instructions and cause the device to: Switch from communication via a first primary channel to communication via a second primary channel at a second wireless node upon detecting an overlapping basic service set (BSS); Obtain a first frame on the second primary channel, the first frame indicating a requested duration of a transmission opportunity (TXOP) associated with the second primary channel; Output an indication of an allowed duration of the TXOP transmitted after obtaining the first frame; and Communicate with at least one first wireless node based on the allowed duration of the TXOP. The apparatus of claim 12, wherein: the first main channel comprises a primary main channel; and the second main channel comprises a chance main channel. The device of claim 12, wherein for communication, the one or more processors are further configured to cause the device to: obtain at least one physical layer protocol data unit (PPDU) according to the allowed duration of the TXOP; and switch back to the first primary channel from the second primary channel after the TXOP ends. A device as claimed in claim 12, wherein the one or more processors are further configured to enable the device to adjust a duration of the TXOP based on the allowed duration of the TXOP. The apparatus of claim 12, wherein the first frame comprises an initial control frame (ICF). The device of claim 12, wherein the one or more processors are further configured to cause the device to calculate the allowed duration based on at least one of: a duration of an overlapping BSS transmission. The apparatus of claim 12, wherein: the TXOP comprises a multi-user (MU) TXOP; and the allowed duration is based on at least one of the requested duration, a short inter-frame space (SIFS) associated with the second wireless node, or a time associated with the transmission of the indication. The apparatus of claim 12, wherein the first frame comprises a trigger frame including at least one of an uplink length field, an allocated duration field, a duration field, or a subfield indicating the requested duration. The apparatus of claim 12, wherein the allowed duration is indicated in at least one of: an uplink length field, an allocated duration field, a duration field, or a subfield of a second frame obtained in response to the first frame. The device of claim 12, further comprising at least one transceiver configured to receive the first frame, wherein the device is configured as a wireless station or an access point (AP). A method for wireless communication at a first wireless node, comprising: Based on detecting an overlapping basic service set (BSS), switching from communication via a first primary channel to communication via a second primary channel; Outputting a first frame for transmission on the second primary channel, the first frame indicating a requested duration of a transmission opportunity (TXOP) associated with the second primary channel; Responsive to the first frame, obtaining an indication of an allowed duration of the TXOP; and Communicating with at least a second wireless node according to the allowed duration of the TXOP. A method for wireless communication at a second wireless node, comprising: switching from communication via a first primary channel to communication via a second primary channel based on detection of an overlapping basic service set (BSS); obtaining a first frame on the second primary channel, the first frame indicating a requested duration of a transmission opportunity (TXOP) associated with the second primary channel; outputting an indication of an allowed duration of the TXOP transmitted after obtaining the first frame; and communicating with at least one first wireless node according to the allowed duration of the TXOP.

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