Uplink (UL) aggregation for multi-link operation (MLO)

Abstract

The present disclosure provides methods, devices, and systems for transmitting and receiving physical protocol data units (PPDUs) over multiple links. In some aspects, a wireless communication device may determine that a first random backoff (RBO) for a first channel of a first link has been countdown to zero. The wireless communication device may determine that a second RBO for a second channel of the second link has a remaining countdown when the first RBO has been countdown to zero. The wireless communication device may optionally transmit a medium retention message on a first link that retains a transmission opportunity (TXOP). The wireless communication device may determine whether to wait for the second RBO prior to transmitting on the first link. The wireless communication device may transmit at least a first PPDU on a first link during the TXOP.

Description

[0001] This application is a divisional application of the invention patent application entitled “Uplink (UL) aggregation for multi-link operation (MLO)” with an international application date of March 2, 2021 and application number 202180017706.7 (international application number PCT / US2021 / 020498).

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This application claims priority to U.S. Provisional Application No. 62 / 985,212, filed on March 4, 2020, entitled “UPLINK (UL) AGGREGATION FOR MULTI-LINK OPERATION (MLO)”, U.S. Provisional Application No. 63 / 008,413, filed on April 10, 2020, entitled “UPLINK (UL) AGGREGATION FOR MULTI-LINK OPERATION (MLO)”, and U.S. Patent Application No. 17 / 188,723, filed on March 1, 2021, entitled “UPLINK (UL) AGGREGATION FOR MULTI-LINK OPERATION (MLO)”, which are assigned to the assignee of this application and are incorporated herein by reference in their entirety. Technical Field

[0004] The present disclosure relates generally to wireless communications and, more particularly, to aggregation of uplink transmissions in multi-link operations (MLO). Background Art

[0005] A wireless local area network (WLAN) may be formed by one or more access points (APs) that provide a shared wireless communication medium for use by several client devices, also referred to as stations (STAs). The basic building block of a WLAN that complies with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards is a basic service set (BSS) managed by an AP. Each BSS is identified by a basic service set identifier (BSSID) announced by the AP. The AP periodically broadcasts beacon frames to enable any STA within the wireless range of the AP to establish or maintain a communication link with the WLAN. Summary of the invention

[0006] The systems, methods, and devices of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0007] An innovative aspect of the subject matter described in the present disclosure may be implemented in a method for wireless communication. The method includes determining that a first random backoff (RBO) for a first channel of a first link has been counted down to zero. The method further includes determining that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero. Additionally, the method further includes determining whether to wait for a second RBO before transmitting on the first link. Additionally, the method further includes transmitting at least a first physical protocol data unit (PPDU) on the first link during a transmission opportunity (TXOP) that begins when the first RBO has been counted down to zero.

[0008] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a wireless communication device. 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. When the processor-readable code is executed by the at least one processor in combination with the at least one modem, the wireless communication device is configured to: determine that the first RBO for the first channel of the first link has been counted down to zero. The wireless communication device is further configured to determine that the second RBO for the second channel of the second link has a remaining countdown when the first RBO has been counted down to zero. Additionally, the wireless communication device is further configured to determine whether to wait for the second RBO before transmitting on the first link. Additionally, the wireless communication device is further configured to transmit at least a first PPDU on the first link during the TXOP.

[0009] Another innovative aspect of the subject matter described in the present disclosure may be implemented in an apparatus for wireless communication by a wireless communication device, the apparatus comprising a device for determining that a first RBO for a first channel of a first link with an access point has been counted down to zero. The apparatus further comprises a device for determining that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero. Additionally, the apparatus further comprises a device for transmitting a medium reservation message for reserving a TXOP on the first link. Additionally, the apparatus further comprises a device for determining whether to wait for a second RBO before transmitting on the first link. Additionally, the apparatus further comprises a device for transmitting at least a first PPDU on the first link during the TXOP.

[0010] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a computer-readable medium comprising stored instructions for wireless communications by a wireless communication device, the instructions being executable by a processor to: determine that a first RBO for a first channel of a first link has been counted down to zero. The instructions are further executable to determine that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero. Additionally, the instructions are further executable to transmit a medium reservation message on the first link to reserve a TXOP. Additionally, the instructions are further executable to determine whether to wait for a second RBO before transmitting on the first link. Additionally, the instructions are further executable to transmit at least a first PPDU on the first link during the TXOP.

[0011] In some implementations, the methods and wireless communication devices may be configured to: determine that the second RBO has been counted down to zero in response to determining to wait for the second RBO; and transmit the second PPDU on the second link. The start time and end time of the first PPDU and the second PPDU are aligned.

[0012] In some implementations, these methods and wireless communication devices may be configured to transmit a medium reservation message reserving a TXOP on a first link.

[0013] In some implementations, the medium reservation message is one of a Clear to Send to Self (CTS2Self) message or a modified Request to Send (RTS) message.

[0014] In some implementations of these methods and wireless communication devices, determining whether to wait for the second RBO before transmitting on the first link includes determining to transmit the first PPDU without waiting in response to determining that the second RBO is greater than a threshold.

[0015] In some implementations of these methods and wireless communication devices, determining whether to wait for the second RBO before transmitting on the first link includes: determining to transmit the first PPDU without waiting in response to determining that the second channel is blocked by a network allocation vector (NAV).

[0016] In some implementations of these methods and wireless communication devices, the medium reservation message interrupts a second RBO for the second link. These methods and wireless communication devices may be configured to restore the second RBO after the medium reservation message.

[0017] In some implementations of these methods and wireless communication devices, determining whether to wait for a second RBO before transmitting on the first link is based on a probability of accessing the second link and an idle period on the first link between the medium reservation message and the expected availability of the second link.

[0018] In some implementations of these methods and wireless communication devices, determining whether to wait for the second RBO before transmitting on the first link includes: determining to wait for the second RBO before transmitting on the first link; and determining to transmit on the first link without waiting in response to determining that the second link is blocked. Determining that the second link is blocked may include determining that the wait time has expired.

[0019] In some implementations of the methods and wireless communication devices, the access point refrains from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

[0020] In some implementations of these methods and wireless communication devices, the access point for the second link announces an EDCA set including second stage enhanced distributed channel access (EDCA) parameters. These methods and wireless communication devices can be configured to adjust the second RBO based on the second stage EDCA parameters in response to transmitting the medium reservation message.

[0021] In some implementations of these methods and wireless communication devices, the first RBO and the second RBO are initialized with the same value.

[0022] In some implementations, the methods and wireless communication devices may be configured to: determine that a remaining countdown of the second RBO is less than a threshold; and set the remaining countdown of the second RBO to zero.

[0023] In some implementations, the methods and wireless communication devices may be configured to: select a new RBO for a second channel of a second link; and increase the new RBO based on a residual value of the second RBO.

[0024] In some implementations, increasing the new RBO based on the residual value of the second RBO includes multiplying the residual value of increasing the new RBO by a configurable weighting factor.

[0025] In some implementations, the methods and wireless communication devices may be configured to add an offset to the first RBO and the second RBO based on a configurable weighting factor. Transmitting at least a first PPDU on the first link during the TXOP may include transmitting the first PPDU on the first link and transmitting the second PPDU on the second link in response to determining that the first RBO or the second RBO has been counted down to zero. The start time and the end time of the first PPDU and the second PPDU may be aligned.

[0026] In some implementations of these methods and wireless communication devices, determining whether to wait for the second RBO before transmitting on the first link includes: determining to wait for the second RBO before transmitting on the first link; resetting the first RBO in response to another device using the first channel; and waiting for the first RBO and the second RBO to count down to zero. In some implementations, resetting the first RBO includes: setting the value of the first RBO based on the remaining countdown of the second RBO.

[0027] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a method for wireless communication. The method includes announcing a first enhanced distributed channel access (EDCA) set, the first EDCA set including a first EDCA parameter for a first link. The method includes announcing a second EDCA set, the second EDCA set including a second EDCA parameter for a second link. The method includes receiving a first physical protocol data unit (PPDU) from a station on a first link during the TXOP. The method includes receiving a second PPDU from the station on a second link during the TXOP. The start time and the end time of the first PPDU and the second PPDU are aligned.

[0028] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a wireless access point. The wireless access point 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. When the processor-readable code is executed by the at least one processor in combination with the at least one modem, the wireless access point is configured to: the processor is configured to: announce a first EDCA set, the first EDCA set including first EDCA parameters for a first link. The wireless access point is configured to: announce a second EDCA set, the second EDCA set including second EDCA parameters for a second link. The wireless access point is configured to: receive a first PPDU from a station on a first link during the TXOP. The wireless access point is configured to: receive a second PPDU from the station on a second link during the TXOP. The start time and the end time of the first PPDU and the second PPDU are aligned.

[0029] Another innovative aspect of the subject matter described in the present disclosure may be implemented in an apparatus for wireless communication by a wireless communication device, the apparatus comprising means for announcing a first EDCA set, the first EDCA set comprising first EDCA parameters for a first link. The apparatus comprises means for announcing a second EDCA set, the second EDCA set comprising second EDCA parameters for a second link. The apparatus comprises means for receiving a first PPDU from a station on the first link during the TXOP. The apparatus comprises means for receiving a second PPDU from the station on the second link during the TXOP. The start time and the end time of the first PPDU and the second PPDU are aligned.

[0030] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a computer-readable medium comprising stored instructions for wireless communication by a wireless communication device, the instructions executable by a processor to: announce a first EDCA set, the first EDCA set comprising first EDCA parameters for a first link. The instructions are further executable to announce a second EDCA set, the second EDCA set comprising second EDCA parameters for a second link. The instructions are further executable to receive a first PPDU from a station on the first link during the TXOP. The instructions are further executable to receive a second PPDU from the station on the second link during the TXOP. The start time and the end time of the first PPDU and the second PPDU are aligned.

[0031] In some implementations, the methods and wireless communication devices may be configured to receive a medium reservation message on the first link reserving the TXOP for the station.

[0032] In some implementations, the medium reservation message is one of a CTS2Self message or a modified RTS message.

[0033] In some implementations, the methods and wireless communication devices may be configured to refrain from transmitting a downlink PPDU on the second link during the TXOP in response to the medium reservation message.

[0034] In some implementations, the second EDCA set includes: first-stage EDCA parameters to be used when the station has not yet mastered another channel, and second-stage EDCA parameters to be used when the station has mastered another channel, and a random backoff (RBO) range of the second-stage EDCA parameters includes a value smaller than the RBO range of the first-stage EDCA parameters.

[0035] Details of one or more implementations of the subject matter described in the present disclosure are set forth in the accompanying drawings and the following description. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. It should be noted that the relative sizes of the following drawings may not be drawn to scale. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 A schematic diagram of an example wireless communication network is shown.

[0037] Figure 2A An example physical (PHY) protocol data unit (PPDU) that may be used for communications between an access point (AP) and a number of stations (STAs) is shown.

[0038] Figure 2B Shows Figure 2A Example fields in a PDU.

[0039] Figure 3A Another example PPDU that may be used for communication between an AP and several STAs is shown.

[0040] Figure 3B Another example PDU that may be used for communication between an AP and several STAs is shown.

[0041] Figure 4 A block diagram of an example wireless communication device is shown.

[0042] Figure 5A A block diagram of an example access point (AP) is shown.

[0043] Figure 5B A block diagram of an example station (STA) is shown.

[0044] Fig. 6A Example scenarios for multi-link operation using synchronous PPDUs with point coordination function (PCF) interframe space (PIFS) access are shown.

[0045] Figure 6B Example scenarios for multi-link operation (MLO) using synchronous PPDUs without PIFS access are shown.

[0046] Figure 7 An example scenario for multi-link operation including a medium reservation message to wait for a second link to become available is shown.

[0047] Figure 8 An example scenario for multi-link operation including medium reservation messages and secondary link parameters is shown.

[0048] Fig. 9 A block diagram of an example wireless communication device is shown.

[0049] Fig.10 A flow chart illustrating an example process for transmitting over multiple links is shown.

[0050] Fig.11 Show explanation Fig.10 A flowchart of an example process with additional optional blocks is provided.

[0051] Fig.12 A block diagram of an example wireless communication device is shown.

[0052] Fig.13 A flow chart illustrating an example process for receiving PPDUs on multiple links is shown.

[0053] Fig.14 An example state transition diagram including different states for a wireless device utilizing a credit-based enhanced distributed channel access (EDCA) mechanism is shown.

[0054] Like reference numbers and designations in the various drawings indicate like elements. DETAILED DESCRIPTION

[0055] The following description is directed to some specific implementations in order to describe the innovative aspects of the present disclosure. However, one of ordinary skill in the art will readily recognize that the teachings herein can be applied in many different ways. The described implementations can be implemented in a manner that can be implemented in accordance with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, the Bluetooth Special Interest Group (SIG) standard, or the like. 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, or the like released 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.

[0056] Multi-link operation (MLO) allows physical (PHY) protocol data units (PPDUs) to be sent on more than one link between a STA and an AP. These links may be carried on different channels, which may be in different frequency bands. Based on the frequency band or channel separation and filter performance, there may be restrictions on how the PPDU is sent on each of these links.

[0057] In basic transmission mode, there may be multiple primary links, but the device may transmit on one link at a time. The device (such as an AP or STA) may count down the random backoff (RBO) on both links. The device may transmit on the link that wins the medium. The other links may be blocked by intra-device interference. For example, the leakage into the second frequency band may be greater than about -62dBm. As such, the basic transmission mode may not achieve aggregate gain.

[0058] In asynchronous transfer mode, the device can count down the RBO on both links. PPDU transmission can be performed independently on each link. When the device can support simultaneous transmission and reception (for example, when the frequency bands have sufficient spacing (such as 2.4 GHz band and 5 GHz band)), asynchronous transfer mode may be possible. Asynchronous transfer mode can provide both latency gain and aggregation gain. However, asynchronous transfer mode can utilize expensive filters (in terms of size or material), which may not be feasible for client devices (such as STA).

[0059] In synchronous PPDU transmission mode, the device can count down the RBO on both links. If the first link wins the medium, both links can transmit PPDUs simultaneously. Simultaneous transmission can minimize intra-device interference. Synchronous PPDU transmission mode can work with low filter performance. Synchronous PPDU transmission mode can provide both latency gain and aggregation gain.

[0060] The various implementations disclosed herein generally involve transmitting synchronous PPDUs on channels on different frequency bands of different links by waiting for the random backoff (RBO) of the second link to count down to zero while reserving a transmission opportunity (TXOP) for the first link. Some implementations more specifically involve determining whether to wait for the second RBO before transmitting on the first link. By waiting for the second RBO, the wireless device may be able to increase the transmission bandwidth by transmitting two PPDUs with aligned start and end times to minimize interference between devices. In some implementations, the wireless device may determine whether to wait for the second RBO based on a trade-off between the added bandwidth of the second link and the idle time of the first link when waiting for the second RBO. For example, in some implementations, when the second RBO exceeds a threshold or the second link is blocked or becomes blocked while waiting, the wireless device may determine not to wait. In some implementations, the wireless device may select or adjust the value of the second RBO to increase the possibility that the second RBO counts down to zero. For example, the wireless device may set the second RBO to zero to allow transmission on the second link. In some implementations, the wireless device may store the residual value of the second RBO when adjusting the second RBO. The wireless device may increase a second RBO for subsequent transmissions based on the residual value.

[0061] 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 achieve one or both of bandwidth gain and latency reduction compared to single link transmissions. For example, by selectively using synchronous transmissions on a first link and a second link, the subject matter described herein may increase transmission bandwidth when channels of the two links are available. In addition, because the wireless device can transmit on whichever link becomes available first without waiting for the second link, the subject matter described herein may reduce latency. Additionally, in the case where the wireless device adjusts the second RBO, increasing the second RBO for subsequent transmissions may improve fairness to other devices that share the channels of the second link.

[0062] Figure 1A 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 the standards defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be. The WLAN 100 may include numerous wireless communication devices, such as an access point (AP) 102 and a plurality of stations (STAs) 104. Although only one AP 102 is shown, the WLAN network 100 may also include a plurality of APs 102. In an aspect, one or more wireless communication devices, such as STAs 104, may include a multi-link Tx component 915 as described herein. In an aspect, one or more wireless communication devices, such as AP 102, may include a multi-link Rx component 1215 as described herein.

[0063] 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 mobile phones, personal digital assistants (PDAs), other handheld devices, netbooks, notebook computers, tablet computers, laptops, display devices (e.g., TVs, computer monitors, navigation systems, etc.), music or other audio or stereo equipment, remote control devices (“remote controls”), printers, kitchen or other home appliances, key fobs (e.g., for passive keyless entry and start (PKES) systems), and other possibilities.

[0064] 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 respective AP 102 . Figure 1Additionally shown is an example coverage area 106 of the AP 102, which may represent a basic service area (BSA) of the WLAN 100. The BSS may be identified to users by a service set identifier (SSID) and may also be identified to other devices by a basic service set identifier (BSSID), which may be a media access control (MAC) address of the AP 102. The AP 102 periodically broadcasts a beacon frame (“beacon”) including the BSSID to enable any STA 104 within the wireless range of the AP 102 to “associate” or re-associate with the AP 102 to establish or maintain a corresponding communication link 108 (hereinafter also referred to as a “Wi-Fi link”) with the AP 102. For example, the beacon may include an identification of a primary channel used by the corresponding AP 102 and a timing synchronization function for establishing or maintaining timing synchronization with the AP 102. The AP 102 may provide access to external networks to the respective STAs 104 in the WLAN via the corresponding communication links 108.

[0065] To establish a communication link 108 with the AP 102, each STA 104 is configured to perform passive or active scanning operations ("scanning") 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, the STA 104 listens for beacons transmitted by the corresponding AP 102 at periodic time intervals, referred to as target beacon transmission times (TBTTs), measured in time units (TUs), where one TU may be equal to 1024 microseconds (μs). To perform an active scan, the STA 104 generates 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 to associate with based on the scan information obtained through passive or active scanning, and perform authentication and association operations to establish a communication link 108 with the selected AP 102. 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.

[0066] As a result of the increasing popularity of wireless networks, a STA 104 may have the opportunity to select one of many B9s within the STA's range or to select among multiple APs 102 that together form an extended service set (ESS) (including multiple connected B9s). An extended network station 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 be associated with different APs 102 at different times for different transmissions. Additionally, 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 102 with a more suitable network characteristic (such as a larger received signal strength indicator (RSSI) or a reduced traffic load).

[0067] In some cases, STA 104 may form a network without AP 102 or other equipment other than STA 104 itself. An example of such a network is an ad hoc network (or wireless ad hoc network). An ad hoc network may alternatively be referred to as a mesh network or a peer-to-peer (P2P) network. In some cases, an ad hoc network may be implemented within a larger wireless network (such as WLAN 100). In such an implementation, although STA 104 may be able to communicate with each other through AP 102 using a communication link 108, STA 104 may also communicate directly with each other via a direct wireless link 110. Additionally, two STAs 104 may communicate via a direct communication link 110, regardless of whether the two STAs 104 are associated with and served by the same AP 102. In such an ad hoc system, one or more STAs 104 may assume the role played by AP 102 in a BSS. Such a STA 104 may be referred to as a group master (GO) and may coordinate transmissions within the ad hoc network. Examples of direct wireless link 110 include a Wi-Fi Direct connection, a connection established by using a Wi-Fi Tunneled Direct Link Setup (TDLS) link, and other P2P group connections.

[0068] The AP 102 and the STA 104 may function and communicate (via corresponding communication links 108) in accordance with the IEEE 802.11 family of wireless communication protocol standards, such as those defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 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 PHY protocol data units (PPDUs) (or physical layer convergence protocol (PLCP) PDUs). The AP 102 and STA 104 in the WLAN 100 may transmit PPDUs on an unlicensed spectrum, which may be a portion of a spectrum that includes frequency bands traditionally used by Wi-Fi technology, such as the 2.4 GHz band, the 5 GHz band, the 60 GHz band, the 3.6 GHz band, and the 900 MHz band. Some implementations of the AP 102 and STA 104 described herein may also communicate in other frequency bands, such as the 6 GHz band, that may support both licensed and unlicensed communications. The AP 102 and STA 104 may also be configured to communicate on other frequency bands, such as shared licensed frequency bands, where multiple operators may have licenses to operate in one or more of the same or overlapping frequency bands.

[0069] Each frequency band may include multiple sub-bands or frequency channels. For example, PPDUs that comply with IEEE 802.11n, 802.11ac, 802.11ax, and 802.11be standard amendments may be transmitted on 2.4 GHz, 5 GHz, or 6 GHz frequency bands, where each frequency band is divided into multiple 20 MHz channels. In this way, these PPDUs are transmitted on a physical channel with a minimum bandwidth of 20 MHz, but larger channels may be formed by channel bonding. For example, a PPDU may be transmitted on a physical channel with a bandwidth of 40 MHz, 80 MHz, 160 MHz, or 320 MHz by bonding multiple 20 MHz channels together.

[0070] Each PPDU is a composite structure including 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 the receiving device to decode subsequent data in the PSDU. In an instance where the PPDU is transmitted over a bonded channel, the preamble field can be replicated and transmitted in each of a plurality of component channels. The PHY preamble may include both a legacy portion (or "legacy preamble") and a non-legacy portion (or "non-legacy preamble"). Legacy preambles can be used for packet detection, automatic gain control, and channel estimation, etc. Legacy preambles can also be generally used to maintain compatibility with legacy devices. The format, decoding, and information provided therein of the non-legacy portion of the preamble are based on the specific IEEE 802.11 protocol to be used to transmit the payload.

[0071] Figure 2A An example protocol data unit (PDU) 200 that can be used for wireless communication between an AP and a number of STAs is shown. For example, the PDU 200 can be configured as a PPDU. As shown, the PDU 200 includes a PHY preamble 202 and a PHY payload 204. For example, the preamble 202 can include a legacy portion, which itself includes a legacy short training field (L-STF) 206 that can be composed of two BPSK symbols, a legacy long training field (L-LTF) 208 that can be composed of two BPSK symbols, and a legacy signal field (L-SIG) 210 that can be composed of two BPSK symbols. The legacy portion of the 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 one or more non-legacy fields 212 that comply with, for example, an IEEE wireless communication protocol, such as IEEE 802.11ac, 802.11ax, 802.11be, or a later wireless communication protocol standard.

[0072] L-STF 206 generally enables the receiving device to perform automatic gain control (AGC) and coarse timing and frequency estimation. L-LTF 208 generally enables the receiving device to perform fine timing and frequency estimation, and can also perform initial estimation of the wireless channel. L-SIG 210 generally enables the receiving device to determine the duration of the PDU and use the determined duration to avoid transmitting on the PDU. For example, L-STF 206, L-LTF 208 and L-SIG 210 can be modulated according to a binary phase shift keying (BPSK) modulation scheme. Payload 204 can be modulated according to a BPSK modulation scheme, an orthogonal BPSK (Q-BPSK) modulation scheme, an orthogonal amplitude modulation (QAM) modulation scheme, or another appropriate modulation scheme. Payload 204 may include a PSDU including a data field (DATA) 214, which in turn may carry, for example, a higher layer data in the form of a media access control (MAC) protocol data unit (MPDU) or an aggregated MPDU (A-MPDU).

[0073] Figure 2B Shows Figure 2A 2. An example L-SIG 210 in a PDU 200 of FIG. 210 includes a data rate field 222, a reserved (R) bit 224, a length field 226, a parity (P) bit 228, and a tail field 230. The data rate field 222 indicates the data rate (note that the data rate indicated in the data rate field 212 may not be the actual data rate of the data carried in the payload 204). The length field 226 indicates the packet length, for example, in units of symbols or bytes. The parity bit 228 may be used to detect bit errors. The tail field 230 includes tail bits, which may be used by a receiving device to terminate the operation of a decoder (e.g., a Viterbi decoder). The receiving device may use the data rate and length indicated in the data rate field 222 and the length field 226 to determine the packet duration, for example, in microseconds (μs) or other time units.

[0074] Figure 3AAnother example PDU 300 that can be used for wireless communication between an AP and a number of STAs is shown. The PDU 300 can be used for MU-OFDMA or MU-MIMO transmission. The PDU 300 includes a PHY preamble, which includes a legacy portion 302 and a non-legacy portion 304. The PDU 300 may further include a PHY payload 306 after the preamble (e.g., in the form of a PSDU including a data field 324). The legacy portion 302 of the preamble includes an L-STF 308, an L-LTF 310, and an L-SIG 312. According to the IEEE 802.11ax amendment to the IEEE 802.11 wireless communication protocol standard, the non-legacy portion 304 of the preamble, and the data field 374 may be formatted as a high-efficiency (HE) WLAN preamble and frame, respectively. The non-legacy portion 304 includes a repeating legacy signal field (RL-SIG) 314, a first HE signal field (HE-SIG-A) 316, a second HE signal field (HE-SIG-B) 318 that is encoded separately from the HE-SIG-A 316, a HE short training field (HE-STF) 320, and a number of HE long training fields (HE-LTF) 322. As with the L-STF 308, L-LTF 310, and L-SIG 312, in instances involving the use of bonded channels, the information in the RL-SIG 314 and HE-SIG-A 316 may be replicated and transmitted in each component 20 MHz channel. In contrast, the HE-SIG-B 318 may be unique to each 20 MHz channel and may be targeted to a specific STA 104.

[0075] The RL-SIG 314 may indicate to the HE-compatible STA 104 that the PPDU is a HE PPDU. The AP 102 may use the HE-SIG-A 316 to identify multiple STAs 104 and inform the multiple STAs 104 that the AP has scheduled UL or DL ​​resources for them. The HE-SIG-A 316 may be decoded by each HE-compatible STA 104 served by the AP 102. The HE-SIG-A 316 includes information that may be used by each identified STA 104 to decode the associated HE-SIG-B 318. For example, the HE-SIG-A 316 may indicate the frame format (including the location and length of the HE-SIG-B 318), the available channel bandwidth, the modulation and coding scheme (MCS), and other possibilities. The HE-SIG-A 316 may also include HE WLAN signaling information that may be used by STAs 104 other than the identified STAs 104.

[0076] HE-SIG-B 318 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 318 includes a common field and at least one field that varies from STA to STA ("user-specific"). The common field may indicate the RU distribution to 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 a specific RU and indicate the scheduling 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 corresponding STAs to decode their corresponding RU payloads in the data field 324 .

[0077] Figure 3B An example PPDU 350 that can be used for wireless communication between an AP and a number of STAs is shown. The PPDU 350 can be used for SU, MU-OFDMA, or MU-MIMO transmissions. The PPDU 350 includes a PHY preamble that includes a legacy portion 352 and a non-legacy portion 354. The PPDU 350 may further include a PHY payload 356 (e.g., in the form of a PSDU including a data field 376) after the preamble. The legacy portion 352 includes an L-STF 358, an L-LTF 360, and an L-SIG 362. The non-legacy portion 354 of the preamble, and the data field 376 may be formatted as an extremely high throughput (EHT) WLAN preamble and frame, respectively, according to the IEEE 802.11be revision to the IEEE 802.11 wireless communication protocol standard, or may be formatted as a preamble and frame, respectively, compliant with any later (post-HE) version of a new wireless communication protocol (compliant with future IEEE 802.11 wireless communication protocol standards or other standards).

[0078] The non-legacy portion 354 of the preamble includes a second signal field 366 (referred to herein as "Pre-SIG"), a third signal field 368 (referred to herein as "EHT-SIG-A", but it may also be constructed to be used for other wireless communication protocol versions above EHT and carry version-related information), and a fourth signal field 370 (referred to herein as "EHT-SIG-B", but it may also be constructed to be used for other wireless communication protocol versions above EHT and carry version-related information). The non-legacy portion 354 further includes an additional short training field 372 (referred to herein as "EHT-STF", but it may also be constructed to be used for other wireless communication protocol versions above EHT and carry version-related information) and several additional long training fields 374 (referred to herein as "EHT-LTF", but they may be constructed to be used for other wireless communication protocol versions above EHT and carry version-related information). 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 Pre-SIG 366 and EHT-SIG-A 368 may be replicated and transmitted in each component 20 MHz channel. In some implementations, the EHT-SIG-A 368 may additionally or alternatively carry information in one or more non-primary 20 MHz channels that is different from the information carried in the primary 20 MHz channel. The EHT-SIG-B 370 may be unique to each 20 MHz channel and, as described above, may be specific to a particular STA 104. The non-legacy portion 354 of the preamble may or may not include a repeated legacy signal field (RL-SIG) 364 after the L-SIG 362 and before the Pre-SIG 366.

[0079] The EHT-SIG-A 368 may include one or more jointly encoded symbols and may be encoded in a different block than the block in which the Pre-SIG 366 is encoded. The EHT-SIG-A 368 may be used by the AP to identify multiple STAs 104 and to inform the multiple STAs 104 that the AP has scheduled UL or DL ​​resources. The EHT-SIG-A 368 may be decoded by each compatible STA 104 served by the AP 102. The EHT-SIG-A 368 includes information that may be used by the identified STA 104 to decode the associated EHT-SIG-B 370. The EHT-SIG-A 368 may generally be used by a receiving device to interpret bits in the EHT-SIG-B 370 or the data field 376. For example, the EHT-SIG-A 368 may indicate the location and length of the EHT-SIG-B 370 in each component channel, the available channel bandwidth, and the modulation and coding scheme (MCS), among other things. The EHT-SIG-A 368 may further include a cyclic redundancy check (CRC) (eg, 4 bits) and a tail (eg, 6 bits) that may be used for a binary convolutional code (BCC).

[0080] The EHT-SIG-B 370 may include multiple symbols that may be encoded in a different block than the block in which the EHT-SIG-A 368 is encoded. In some other implementations, the EHT-SIG-A 368 may be jointly encoded with some or all of the EHT-SIG-B 370. For example, the EHT-SIG-A 368 may be jointly encoded with a first portion of the EHT-SIG-B 370 that includes information common to all users served by the PPDU 350. The EHT-SIG-B 370 may carry STA-specific scheduling information, such as, for example, per-user MCS values ​​and per-user RU allocation information. The EHT-SIG-B 370 may generally be used by a receiving device to interpret the bits in the data field 376. In the context of DL MU-OFDMA, such information enables the corresponding STA 104 to identify and decode the corresponding RU in the associated data field 376. Each EHT-SIG-B 370 includes a common field and at least one field that is specific to a STA ("user-specific"). The common field may indicate the RU distribution to 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 a specific RU and indicate the scheduling 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, for example, two user fields that contain information for two corresponding STAs to decode their corresponding RU payloads.

[0081] The Pre-SIG 366 (and the RL-SIG 364, if present) may indicate to the STA 104 that complies with EHT or later versions that the PPDU 350 is an EHT PPDU or a PPDU that complies with another non-legacy wireless communication protocol version. For example, the Pre-SIG 366 may be used by the receiving device to interpret bits in one or more of the EHT-SIG-A 368, the EHT-SIG-B 370, or the data field 376. In some implementations, the Pre-SIG 366 may include a reserved bit that indicates whether the PPDU 350 complies with, for example, EHT or a later version of the IEEE 802.11 wireless communication protocol standard family or other standards (e.g., after IEEE 802.11ax). In some implementations, the Pre-SIG 366 includes a version field that includes at least one bit that indicates the specific wireless communication protocol version that the PPDU 350 complies with.

[0082] Access to the shared wireless medium is typically managed by a distributed coordination function (DCF). With DCF, there is generally no centralized master device that allocates time and frequency resources for the shared wireless medium. Instead, before a wireless communication device (such as AP102 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 may be configured to implement DCF by using carrier sense multiple access (CSMA) (CSMA / CA) technology with collision avoidance (CA) and timing intervals. Before transmitting data, the wireless communication device may perform a clear channel assessment (CCA) and determine that the appropriate wireless channel is idle. CCA includes physical (PHY level) carrier sense and virtual (MAC level) carrier sense. Physical carrier sense is accomplished via measurement of 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 the detected preamble is higher than a threshold, the medium is considered busy. Physical carrier sense also includes energy detection (ED). 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 via the use of a network allocation vector (NAV), which is an indicator of the time when the medium may next become idle. The NAV is reset each time a valid frame is received that is not addressed to the wireless communication device. 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 detected symbols or even if the detected energy is below a related threshold.

[0083] As described above, DCF is implemented by using time intervals. These time intervals include slot times (or "slot intervals") and interframe spaces (IFS). Slot times are basic timing units and can be determined based on one or more of transmit-receive turnaround time, channel sensing time, propagation delay, and MAC processing time. Measurements of channel sensing are performed for each slot. All transmissions can start at slot boundaries. There are different variants of IFS, including short IFS (SIFS), distributed IFS (DIFS), extended IFS (EIFS), and arbitration IFS (AIFS). For example, DIFS can be defined as the sum of SIFS and twice the slot time. The values ​​of slot times and IFS can be provided by suitable standard specifications, such as one of the IEEE 802.11 wireless communication protocol standard family (such as standards defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be).

[0084] When the NAV reaches 0, the wireless communication device performs physical carrier sensing. If the channel remains idle within an appropriate IFS (e.g., DIFS), the wireless communication device initiates a backoff timer (or random backoff (RBO) timer), which indicates the duration of time the device must sense that the medium is idle before the device is allowed to transmit. The backoff timer decrements one slot each time the medium is sensed to be idle during the corresponding time slot interval. If the channel remains idle until the backoff timer expires, the wireless communication device becomes the owner (or "owner") of the transmission opportunity (TXOP) and can begin transmitting. TXOP is the duration of time that the wireless communication device can transmit frames on the channel after the wireless communication device 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 allow transmission.

[0085] Each time a wireless communication device generates a new PPDU for transmission in a new TXOP, the wireless communication device randomly selects a new backoff timer duration. The available distribution of numbers that can be randomly selected for the backoff timer is called a contention window (CW). When the backoff timer expires, if the wireless communication device transmits the PPDU, but the medium is still busy, there may be a conflict. Additionally, if there is too much energy on the wireless channel, resulting in a poor signal-to-noise ratio (SNR), the communication may be damaged or otherwise not successfully received. In such instances, the wireless communication device may not receive a communication confirming the transmission of the PDU within the timeout interval. The MAC may then increase the CW exponentially (e.g., double it) and randomly select a new backoff timer duration from the CW before each retransmission attempted for the PPDU. Before each retransmission attempted, the wireless communication device may wait for a duration of DIFS, and if the medium remains idle, proceed to initiate a new backoff timer. There are different CW and TXOP durations for each of the four access categories (AC): Voice (AC_VO), Video (AC_VI), Background (AC_BK), and Best Effort (AC_BE). This enables specific types of traffic to be prioritized in the network.

[0086] 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 a Figure 1 In some implementations, the wireless communication device 400 may be an example of a device in an AP (such as one of the STAs 104 described above). Figure 1The wireless communication device 400 is capable of transmitting and receiving wireless communications, for example, in the form of wireless packets. For example, the wireless communication device may be configured to transmit and receive packets in the form of physical layer convergence protocol (PLCP) protocol data units (PPDUs) and media access control (MAC) protocol data units (MPDUs) that comply with IEEE 802.11 wireless communication protocol standards (such as those defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be).

[0087] The wireless communication device 400 may be or may include a chip, system on chip (SoC), chipset, package, or device including one or more modems 404 (e.g., Wi-Fi (IEEE 802.11 compliant) modems). In some implementations, one or more modems 404 (collectively, “modems 404”) 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 processors, processing blocks, or processing elements 402 (collectively, “processors 402”) coupled to the modems 404. In some implementations, the wireless communication device 400 additionally includes one or more radios 406 (collectively, “radios 406”) coupled to the modems 404. In some implementations, the wireless communication device 400 further includes one or more memory blocks or elements 408 (collectively, “memory 408”) coupled to the processor 402 or the modem 404.

[0088] The modem 404 may include an intelligent hardware block or device (for example, such as an application specific integrated circuit (ASIC)). The modem 404 is generally configured to implement the PHY layer, and in some implementations also implements a portion of the MAC layer (e.g., a hardware portion of the MAC layer). For example, the modem 404 is configured to modulate packets and output the modulated packets to the radio 406 for transmission on the wireless medium. Similarly, the modem 404 is configured to obtain modulated packets received by the radio 406 and demodulate the packets to provide demodulated packets. In addition to the modulator and demodulator, the modem 404 may further include a digital signal processing (DSP) circuit system, an automatic gain control (AGC) circuit system, an encoder, a decoder, a multiplexer, and a demultiplexer. For example, when in a transmission mode, data obtained from the processor 402 may be provided to an encoder, which encodes the data to provide encoded bits. The encoded bits may then be mapped to a number (N SS) spatial streams for spatial multiplexing or several (N STS The coded bits in each stream may then be mapped (using the selected MCS) to points in the modulation constellation to provide modulated symbols. The modulated symbols in the corresponding spatial stream or space-time stream may be multiplexed, transformed via an inverse fast Fourier transform (IFFT) block, and then provided to the DSP circuit system (e.g., for Tx windowing and filtering). The digital signal may then be provided to a digital-to-analog converter (DAC). The resulting analog signal may then be provided to an upconverter and ultimately to the radio 406. In an implementation involving beamforming, the modulated symbols in the corresponding spatial streams are precoded via a steering matrix before being provided to the IFFT block.

[0089] When in receive mode, the DSP circuit system is configured to acquire a signal including modulated symbols received from the radio 404, for example, by detecting the presence of the signal and estimating initial timing and frequency offset. The DSP circuit system is further configured to digitally condition the signal, for example, using channel (narrowband) filtering and analog impairment conditioning (such as correcting I / Q imbalance), and by applying digital gain to ultimately obtain a narrowband signal. Subsequently, the output of the DSP circuit system may be fed to the AGC, which is configured to use information extracted from the digital signal (e.g., in one or more received training fields) to determine the appropriate gain. The output of the DSP circuit system is also coupled to a demultiplexer that demultiplexes the modulated symbols when multiple spatial streams or space-time streams are received. The demultiplexed symbols may be provided to a demodulator that is configured to extract the 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 that may be configured to process the LLRs to provide decoded bits. The coded bits may then be descrambled and provided to the MAC layer (processor 402) for processing, evaluation, or interpretation.

[0090] The radio 406 generally includes at least one radio frequency (RF) transmitter (or "transmitter chain") and at least one RF receiver (or "receiver chain"), which may be combined into one or more transceivers. For example, each of the RF transmitter and receiver may include various analog circuit systems, 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 having a corresponding transmit chain) and multiple receive antennas (each having a corresponding receive chain). The codewords output from the modem 404 are provided to the radio 406, which then transmits the codewords via the coupled antennas. Similarly, the codewords received via the antennas are obtained by the radio 406, which then provides the codewords to the modem 404.

[0091] The processor 402 may include 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 402 processes information received through the radio 406 and the modem 404, and processes information to be output by the modem 404 and the radio 406 for transmission over a wireless medium. For example, the processor 402 may implement a control plane and at least a portion of a MAC layer, which is configured to perform various operations related to the generation, transmission, reception, and processing of MPDUs, frames, or packets. In some implementations, the MAC layer is configured to generate an MPDU to provide to the PHY layer for encoding, and to receive decoded information bits from the PHY layer for processing as an MPDU. The MAC layer may be further configured to allocate time and frequency resources, for example, for OFDMA, or other operations or technologies. In some implementations, processor 402 may generally control modem 404 to cause the modem to perform the various operations described above.

[0092] The memory 408 may include a tangible storage medium, such as a random access memory (RAM) or a read-only memory (ROM) or a combination thereof. The memory 408 may also store non-transient processor or computer executable software (SW) code containing instructions that, when executed by the processor 402, cause the processor to perform various operations for wireless communication described herein, including generation, transmission, reception, and interpretation of MPDUs, frames, or packets. For example, the various functions of the various components disclosed herein or the various blocks or steps of the methods, operations, processes, or algorithms disclosed herein may be implemented as one or more modules of one or more computer programs.

[0093] Figure 5A 5 shows a block diagram of an example AP 502. For example, the AP 502 may be a reference Figure 1 1. An example implementation of AP 102 is described. AP 502 includes a wireless communication device (WCD) 510 (although AP 502 itself may also be generally referred to as a wireless communication device, as used herein). For example, wireless communication device 510 may be a wireless communication device (WCD) 510. Figure 4 An example implementation of the wireless communication device 400 described herein. The AP 502 also includes a plurality of antennas 520 coupled to the wireless communication device 510 to transmit and receive wireless communications. In some implementations, the 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. The AP 502 further includes at least one external network interface 550 that enables the AP 502 to communicate with a core network or a backhaul network to obtain access to an external network including the Internet. For example, the external network interface 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 in the aforementioned components may communicate directly or indirectly with other components in these components on at least one bus. The AP 502 further includes a housing that encloses the wireless communication device 510, the application processor 530, the memory 540, and at least portions of the antenna 520 and the external network interface 550.

[0094] Figure 5B 5 shows a block diagram of an example STA 504. For example, STA 504 may be a reference Figure 1 104. STA 504 includes a wireless communication device 515 (although STA 504 itself may also be generally referred to as a wireless communication device, as used herein). For example, wireless communication device 515 may be a wireless communication device. Figure 45. The STA 504 further includes one or more antennas 525 coupled to the wireless communication device 515 to transmit and receive wireless communications. The 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, the 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, the STA 504 can further include one or more sensors 575 (such as, for example, one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors). Components in the aforementioned components can communicate directly or indirectly with other components in these components on at least one bus. The STA 504 further includes a housing that encloses the wireless communication device 515, the application processor 535, the memory 545, and at least portions of the antenna 525, the UI 555, and the display 565.

[0095] As described above, in the synchronous PPDU transmission mode for multi-link operation, the wireless device may count down the RBO on the two links. In some cases, the wireless device may be restricted from accessing the channel of the second link at the same time that the wireless device can access the channel of the first link. A multi-link device (MLD) that can transmit and receive simultaneously on multiple links of a given link set may be referred to as a simultaneous transmit receive (STR) device. For example, an MLD with a standard filter can transmit on the 2.4 GHz band and receive on the 5 GHz band at the same time, and is considered an STR device for these links. An MLD that is not capable of transmitting and receiving simultaneously on multiple links of a given link set may be referred to as a non-STR (NSTR) device. For example, an MLD device with a standard filter may not be able to transmit on the 5 GHz band and receive on the 6 GHz band at the same time, and may be considered an NSTR device for these links. In contrast, if the MLD device has a very good filter (which may be true for the AP), the MLD device may be able to transmit on the 5 GHz band and receive on the 6 GHz band at the same time, and may be considered an STR device for these links.

[0096] Fig. 6AAn example scenario 600 for multi-link operation (MLO) using synchronous PPDUs with point coordination function (PCF) interframe space (PIFS) access is shown. When a wireless device gains access to a first channel 610 of a first link 616, the PIFS access allows the wireless device to access a second channel 620 of a second link 626 based on a previous idle period. For example, in the scenario 600, the wireless device may count down a first RBO 612 for the first channel 610 and a second RBO 622 for the second channel 620. When the first RBO 612 counts down to zero, the wireless device may check whether the second channel 620 has been clear (e.g., detected energy is less than about -72 dBm) for a PIFS period. If so, the wireless device may transmit on the second channel 620 as well as the first channel 610.

[0097] In some aspects, for example, where the first channel 610 and the second channel 620 are in different frequency bands, the wireless device may not be allowed to use PIFS access to transmit on the second channel 620. For example, a regulation or standards document may indicate that PIFS access may not be used for inter-band multilink operations.

[0098] Figure 6B An example scenario 650 for multi-link operation using synchronous PPDUs without PIFS access is shown. Similar to scenario 600, the wireless device may count down a first RBO 612 for a first channel 610 and a second RBO 622 for a second channel 620. When the first RBO 612 counts down to zero, the second RBO 622 may have a remaining countdown. For example, when the first RBO 612 counts down to zero, the RBO 622 may have a value of four (4). The second RBO 622 may continue to count down until it reaches zero. If the wireless device is an NSTR device for the first channel 610 and the second channel 620, the wireless device may not be able to monitor the second channel 620 while transmitting on the first channel 610. For example, the wireless device may delay transmission on the first channel 610 until the second RBO 622 counts down to zero. However, if the wireless device does not immediately access the first channel 610 after it wins the first channel 610, some other device may seize the first channel 610. The wireless device may reset the first RBO in response to the other device using the first channel. The wireless device may wait for the first RBO 612 and the second RBO 622 to count down to zero. Accordingly, waiting for the second RBO 622 may result in poor performance, such as the increased waiting time in scenario 650.

[0099] Figure 7An example scenario 700 for multi-link operation including a medium reservation message 710 to wait for a second link to become available is shown. Similar to scenario 600, the wireless device may count down a first RB0 612 for a first channel 610 of a first link 616 and a second RB0 622 for a second channel 620 of a second link 626. The first link 616 and the second link 626 may be in different frequency bands, but transmission on one of these links may cause inter-device interference to the other link. Accordingly, the wireless device may not be able to transmit on one of the first link 616 or the second link 626 and receive on the other of the first link 616 or the second link 626 at the same time. However, the wireless device may be able to transmit on both the first link 616 and the second link 626 at the same time or receive on the first link 616 and the second link 626 at the same time. In some implementations, the first link 616 may be in one of the 5 GHz band or the 6 GHz band, and the second link 626 may be in the other of the 5 GHz band or the 6 GHz band.

[0100] When the first RBO 612 counts down to zero, the second RBO 622 may have a remaining countdown. The wireless device may transmit a medium reservation message 710 on the first channel 610 of the first link 616 to reserve a TXOP 714. In some implementations, the medium reservation message 710 may be a clear to send to oneself (CTS2Self) message to reserve a TXOP 714. In some implementations, the medium reservation message 710 may be a modified request to send (RTS) message requesting a TXOP 714. For example, the modified RTS message may use a special scrambling code to indicate that the PPDU on the first channel 610 may not start immediately. The AP may respond with a CTS message indicating the TXOP 714. The TXOP 714 may be used to transmit a PPDU at any time during the TXOP 714. The wireless device may wait for the second RBO 622 to count down to zero or transmit a PPDU on the first channel 610 without waiting.

[0101] Generally, determining whether to wait for the second RBO 622 before transmitting on the first link 616 may be based on the probability of accessing the second link 626, and the idle period between the medium reservation message and the expected availability of the second link 626 on the first link 616. For example, determining whether to wait for the second RBO may be based on a trade-off between the added bandwidth of the second link 626 and the idle time 712 of the first link 616 when waiting for the second RBO 622. In some implementations, determining whether to wait for the second RBO before transmitting on the first link 616 may include determining to transmit the first PPDU without waiting in response to determining that the remaining countdown of the second RBO 622 is greater than a threshold. The threshold may be configured by the wireless device. In some implementations, determining whether to wait for the second RBO before transmitting on the first link 616 may include determining to transmit the first PPDU without waiting in response to determining that the second channel 620 is blocked by the network allocation vector (NAV). In some implementations, the wireless device may initially determine to wait for the second RBO 622 before transmitting on the first link 616. The wireless device may later determine to transmit on the first link 616 without waiting in response to determining that the second link 626 has become blocked (e.g., by NAV). Determining that the second link 626 has become blocked may include determining that a wait time has expired. For example, the wait time may be configured by the wireless device or indicated by the AP.

[0102] In some aspects, the medium reservation message 710 may cause inter-device interference on the second channel 620. Accordingly, during the period 720, the CCA procedure for the second channel 620 may be blocked and may not be able to count down the second RBO 622. The wireless device may resume counting down the second RBO 622 after the period 720. For example, the wireless device may skip the DIFS or AIFS because the interference on the second link 626 is caused by transmitting the medium reservation message 710 on the first link 616.

[0103] Figure 8An example scenario for multi-link operation including medium reservation message and secondary link parameters is shown. Similar to scenario 700, the wireless device may count down the first RBO 612 for the first channel 610 and the second RBO 622 for the second channel 620. When the first RBO 612 counts down to zero, the second RBO 622 may have a remaining countdown. The wireless device may transmit a medium reservation message 710 for retaining TXOP 714 on the first channel 610 of the first link 616. In scenario 800, the second RBO 622 may have a much larger value than the first RBO 612. In some implementations, the second link 626 may be configured with a secondary enhanced distributed channel access (EDCA) set. The secondary EDCA set may include a first-stage EDCA parameter to be used when the station has not yet mastered another channel and a second-stage EDCA parameter to be used when the station has mastered another channel. The random backoff (RBO) range (contention window) of the second-stage EDCA parameter may include a value less than the RBO range of the first-stage EDCA parameter. The wireless device may adjust the remaining count 810 of the second RBO 622 based on the second stage EDCA parameters in response to transmitting the medium reservation message 710. For example, when the remaining count 810 is less than the threshold (h), the wireless device may adjust the remaining count 810. Accordingly, based on the second stage EDCA parameters, the second RBO 622 is more likely to count down to zero during the TXOP 714. In some aspects, when the wireless device adjusts the remaining count 810 of the second RBO 622, the remaining count 810 may be stored as a residual value (c). The residual value may be regarded as a "credit" that the wireless device has borrowed. The wireless device may add the residual value (possibly together with a weighting factor (α)) to a subsequent RBO for the second link. Accordingly, in order to be fair to other devices, the wireless device counts down the additional α*c before subsequent transmissions on the second link. Parameters h and α may be dynamically configured to achieve fairness. For example, the threshold h may be set to a relatively high value when the channel traffic is relatively low, and to a relatively low value when the channel traffic is relatively high. The weighting factor α may be set to 1 in low traffic scenarios and to a higher value in higher traffic scenarios.

[0104] Fig. 9 A block diagram of an example wireless communication device 900 is shown. In some implementations, the wireless communication device 900 is configured to perform a reference Fig.10 and 11 The wireless communication device 900 may be a reference to the process 1000 described herein. Figure 44. For example, the wireless communication device 900 may be a chip, SoC, chipset, package, or device including 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 900 may be a STA (such as a STA, respectively, or a STA). Figure 1 and 5B In some other implementations, the wireless communication device 900 may be a STA including such a chip, SoC, chipset, package or device and at least one transmitter, at least one receiver and at least one antenna.

[0105] The wireless communication device 900 includes a processor 905 and a memory 910. The wireless communication device 900 may include a multi-link Tx component 915, which may include a first RBO component 920, a second RBO component 925, a reservation component 930, a first transmission component 940, a second transmission component 945, and an RBO adjustment component 950. Portions of one or more of the components 915, 920, 925, 930, 940, 945, and 950 may be implemented at least in part in hardware or firmware. For example, the multi-link Tx component 915 may be implemented at least in part by a modem (such as modem 404). In some implementations, at least some of the components 915, 920, 925, 930, 940, 945, and 950 are implemented at least in part as software stored in a memory (such as memory 408 or memory 910). For example, portions of one or more of components 915, 920, 925, 930, 940, 945, and 950 may be implemented as non-transient instructions (or "code") that can be executed by a processor (such as processor 402 or processor 905) to perform the functions or operations of the corresponding component.

[0106] The multi-link Tx component 915 is configured to transmit synchronous PPDUs on channels on different frequency bands of different links by reserving a TXOP for the first link 616 while waiting for the RBO of the second link 626 to count down to zero.

[0107] The first RBO component 920 is configured to: count down a first RBO for a first channel of the first link 616; and determine that the first RBO has been counted down to zero.

[0108] The second RBO component 925 is configured to count down a second RBO for a second channel of the second link 626, and determine that the second RBO has a remaining countdown when the first RBO has been counted down to zero. In some implementations, the second RBO component 925 may be configured to determine that the second RBO has been counted down to zero in response to determining that the second RBO is to be waited.

[0109] The reservation component 930 is configured to transmit a medium reservation message reserving the TXOP on the first link 616. In some implementations, the medium reservation message is one of a CTS2Self message or a modified RTS message.

[0110] The wait decision component 935 is configured to determine whether to wait for a second RBO before transmitting on the first link 616 .

[0111] The first transmitting component 940 is configured to transmit at least a first PPDU on the first link 616 during the TXOP.

[0112] The second transmitting component 945 is configured to transmit the second PPDU on the second link 626. The second transmitting component 945 can align the start time and the end time of the first PPDU and the second PPDU.

[0113] Fig.10 A flow chart illustrating an example process 1000 for transmitting on multiple links is shown. Process 1000 may be performed by a wireless communication device (such as a wireless communication device such as a wireless communication device). Figure 4 In some implementations, process 1000 may be performed by a STA (such as a wireless communication device 400 described in detail in the accompanying drawings). Figure 1 and Figure 5B The STA 104 and 504 described above may be one of which may be used to perform the wireless communication operation. Optional blocks are shown with dashed lines.

[0114] At block 1002, process 1000 includes determining that a first RBO for a first channel of a first link 616 has been counted down to zero. For example, in one aspect, the wireless communication device 900, the processor 905, the memory 910, the multi-link Tx component 915, or the first RBO component 920 may be configured to perform or may include means for performing the following operations: determining that a first RBO for a first channel of a first link 616 with an access point has been counted down to zero. For example, the first RBO component 920 may count down (e.g., decrement) the first RBO 612 each time the first channel is not occupied in a time slot. The first RBO component 920 may determine that the first RBO 612 has been counted down to zero when the value of the first RBO 612 reaches zero.

[0115] At block 1004, the process 1000 includes determining that a second RBO for a second channel of a second link 626 has a remaining countdown when the first RBO has been counted down to zero. For example, in one aspect, the wireless communication device 900, the processor 905, the memory 910, the multi-link Tx component 915, or the second RBO component 925 may be configured to perform the following operations or may include means for the following operations: determining that a second RBO 622 for a second channel 620 of a second link 626 has a remaining countdown when the first RBO 612 has been counted down to zero. For example, the second RBO component 925 may determine the value of the second RBO 622 in response to the first RBO component 920 indicating that the first RBO 612 has been counted down to zero. If the value of the second RBO 622 is greater than zero, the second RBO component 925 may determine that the second link 626 has a remaining countdown.

[0116] At block 1006, the process 1000 may optionally include transmitting a medium reservation message on the first link 616 to reserve the TXOP. For example, in one aspect, the wireless communication device 900, the processor 905, the memory 910, the multi-link Tx component 915, or the reservation component 930 may be configured to perform the following operations or may include means for the following operations: transmitting a medium reservation message 710 on the first link 616 to reserve the TXOP 714. In some implementations, the medium reservation message 710 is one of a CTS2Self message or a modified RTS message. The medium reservation message 710 may reserve the first channel 610 of the first link 616 so that other devices do not obtain the first channel 610 when the wireless communication device 900 is waiting for the second RBO 622. The CTS2Self message may be transmitted by the wireless communication device 900 without involving the AP. The modified RTS message may notify the AP that the PPDU may be delayed. The AP may transmit a CTS message that may be received by an additional device (such as a hidden node), thereby preventing conflicts during the TXOP 714.

[0117] At block 1008, process 1000 includes determining whether to wait for a second RBO before transmitting on the first link 616. For example, in one implementation, the wireless communication device 900, the processor 905, the memory 910, the multi-link Tx component 915, or the wait decision component 935 may be configured to perform or may include means for determining whether to wait for a second RBO before transmitting on the first link 616. In some implementations, the determination in block 1008 may be based on the probability of accessing the second link 626 and the idle time 712 on the first link 616 between the medium reservation message 710 and the expected availability of the second link 626. The expected availability of the second link 626 may be estimated based on the second RBO 622. In some implementations, the wait decision component 935 may apply a rule to determine whether to wait for the second RBO 622. For example, the wait decision component 935 may determine to transmit the first PPDU without waiting in response to determining that the second RBO is greater than a threshold. The threshold may be based on the configuration of the wait decision component 935. In one implementation, the threshold may be selected based on a machine learning process that selects the threshold to optimize a transmission metric such as latency or bandwidth. As another example, the wait decision component 935 may determine to transmit the first PPDU without waiting in response to determining that the second channel is blocked by the NAV. Further details on determining to wait for the second RBO 622 are provided below. Fig.11 to describe.

[0118] At block 1010, the process 1000 includes transmitting at least a first PPDU on the first link 616 during the TXOP. For example, in an aspect, the wireless communication device 900, the processor 905, the memory 910, the multi-link Tx component 915, or the first transmitting component 940 may be configured to perform or may include means for transmitting at least a first PPDU 614 on the first link 616 during the TXOP 714.

[0119] Fig.11 A flow chart illustrating additional optional blocks of the example process 1000 is shown.

[0120] In some implementations, at block 1102, the process 1000 may include adjusting the second RBO in response to transmitting a medium reservation message. For example, in one aspect, the wireless communication device 900, the processor 905, the memory 910, the multi-link Tx component 915, or the RBO adjustment component 950 may be configured to adjust the second RBO 622 in response to transmitting a medium reservation message 710. For example, in some implementations, the access point (AP) of the second link 626 may announce an EDCA set including a second-stage EDCA parameter. The RBO adjustment component 950 may adjust the second RBO 622 based on the second-stage EDCA parameter in response to transmitting a medium reservation message. As another example, in some implementations, the RBO adjustment component 950 may determine that the remaining countdown of the second RBO 622 is less than a threshold value (h). The adjustment component 950 may set the remaining countdown of the second RBO 622 to zero. In some implementations, the RBO adjustment component 950 may store the remaining countdown of the second RBO 622 as a residual value (c).

[0121] In some implementations, at block 1104, the process 1000 may include determining to wait for a second RBO before transmitting on the first link 616. For example, the wait decision component 935 may determine that the second RBO is less than a threshold. The wait decision component 935 may reset the first RBO in response to another device using the first channel. For example, the wait decision component 935 may set the value of the first RBO based on the remaining countdown of the second RBO. For example, the wait decision component 935 may set the value of the first RBO to the remaining countdown of the second RBO. In one implementation, the value of the first RBO may be within 5% of the remaining countdown of the second RBO. The wireless device 900 may wait for the first RBO 612 and the second RBO 622 to count down to zero.

[0122] In some implementations, process 1000 may include resuming second RBO 622 after the medium reservation message at block 1106. For example, second RBO component 925 may resume second RBO 622 after medium reservation message 710. Second RBO component 925 may continue to count down second RBO 622 in each time slot in which the second channel is not occupied.

[0123] In some implementations, at block 1108 , process 1000 may include determining whether the second RBO has been counted down to zero.

[0124] In some implementations, at block 1110, process 1000 may include determining that the second RBO has been counted down to zero in response to determining to wait for the second RBO. For example, second RBO component 925 may determine that second RBO 622 has been counted down to zero in response to determining to wait for the second RBO 622.

[0125] In some implementations, at block 1112, process 1000 may include transmitting a second PPDU on second link 626. In one aspect, for example, second transmitting component 945 may transmit the second PPDU on second link 626. The start time and end time of the first PPDU and the second PPDU are aligned.

[0126] In some implementations, at block 1114, process 1000 may include determining to transmit on first link 616 without waiting in response to determining that second link 626 is blocked. For example, determining that second link 626 is blocked may include determining that a wait time has expired. The wait time may be configured for wireless communication device 900. In some implementations, the AP may configure the wait time as a maximum time allowed between the medium reservation message and the transmission of the PPDU.

[0127] In some implementations, process 1000 may include selecting a new RBO for a second channel of the second link at block 1116. For example, the new RBO may be based on the first phase EDCA parameters for the second link.

[0128] In some implementations, at block 1118, process 1000 may include increasing the new RBO based on the residual value of the second RBO. For example, the RBO adjustment component 950 may add the residual value c to the new RBO. In some implementations, the residual value c may be adjusted by a weighting factor α. For example, the RBO adjustment component 950 may add the value of α*c to the new RBO. The increase in the new RBO may compensate for the previous reduction of the second RBO to achieve fairness to other devices sharing the second link. In some implementations, the first new RBO for the first channel and the second new RBO for the second channel may be increased based on EDCA parameters such as a threshold h, a weighting factor α, or a combination thereof. For example, the RBO adjustment component 950 may add an offset to the first new RBO and the second new RBO to establish a credit. For example, the RBO adjustment component 950 may add the value of α*h to the first new RBO and the second new RBO. When the first new RBO or the second new RBO counts down to zero, the wireless communication device 400 may transmit a PPDU on both the first channel and the second channel.

[0129] Fig.12 A block diagram of an example wireless communication device 1200 is shown. In some implementations, the wireless communication device 1200 is configured to perform a reference Fig.13 The wireless communication device 1200 may be a reference to Figure 41. For example, the wireless communication device 1200 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 1200 may be a processor for use in an AP (such as a wireless modem or a wireless modem). Figure 1 and 5A In some other implementations, the wireless communication device 1200 may be an AP including such a chip, SoC, chipset, package or device and at least one transmitter, at least one receiver and at least one antenna.

[0130] The wireless communication device 1200 includes a processor 1205 and a memory 1210. The wireless communication device 1200 may include a multi-link Rx component 1215, which may include a first EDCA component 1220, a second EDCA element 1225, a reservation component 1230, a first receive component 1240, a second receive component 1245, and an optional downlink component 1250. Portions of one or more of the components 1215, 1220, 1225, 1230, 1240, 1245, and 1250 may be implemented at least in part in hardware or firmware. For example, the multi-link Rx component 1215 may be implemented at least in part by a modem, such as the modem 404. In some implementations, at least some of the components 1215, 1220, 1225, 1230, 1240, 1245, and 1250 are at least partially implemented as software stored in a memory, such as memory 408 or memory 1210. For example, portions of one or more of the components 1215, 1220, 1225, 1230, 1240, 1245, and 1250 may be implemented as non-transitory instructions (or "code") that can be executed by a processor, such as processor 402 or processor 1205, to perform the functions or operations of the corresponding module.

[0131] The first EDCA component 1220 is configured to announce a first EDCA set including first EDCA parameters for the first link 616 .

[0132] The second EDCA component 1225 is configured to announce a second EDCA set including second EDCA parameters for the second link 626 .

[0133] The reserving component 1230 is configured to receive a medium reservation message on the first link 616 reserving a TXOP for a station.

[0134] The first receiving component 1240 is configured to receive a first PPDU on the first link 616 during the TXOP and to receive a second PPDU on the second link 626 during the TXOP.

[0135] The second receiving component 1245 is configured to receive a second PPDU during the TXOP on the second link 626. The start time and the end time of the first PPDU and the second PPDU are aligned.

[0136] The downlink component 1250 is configured to refrain from transmitting a downlink PPDU on the second link 626 during the TXOP in response to the medium reservation message.

[0137] Fig.13 1 is a flowchart illustrating an example process 1300 for receiving a PPDU on multiple links. The operations of process 1300 may be implemented by an AP or components thereof as described herein. For example, process 1300 may be performed by a wireless communication device (such as a wireless communication device described in conjunction with FIG. 1 ). Figure 4 In some implementations, process 1300 may be performed by an AP (such as the wireless communication device 400 described in detail in the accompanying drawings). Figure 1 and 5A 1 and 502 described herein).

[0138] At block 1302, the process 1300 includes announcing a first EDCA set, the first EDCA set including first EDCA parameters for the first link 616. For example, in an aspect, the wireless communication device 1200, the processor 1205, the memory 1210, the multi-link Rx component 1215, or the first EDCA component 1220 may be configured to perform or may include means for announcing a first EDCA set, the first EDCA set including first EDCA parameters for the first link 616. For example, the first EDCA component 1220 may transmit a timing announcement frame indicating the first EDCA set.

[0139] At block 1304, the process 1300 includes announcing a second EDCA set including second EDCA parameters for the second link 626. For example, in an aspect, the wireless communication device 1200, the processor 1205, the memory 1210, the multi-link Rx component 1215, or the second EDCA component 1225 may be configured to perform or may include means for announcing a second EDCA set including second EDCA parameters for the second link 626. For example, the second EDCA component 1225 may transmit a timing announcement frame indicating the second EDCA set.

[0140] At block 1306, the process 1300 may optionally include receiving a medium reservation message on the first link 616 that reserves a TXOP for the station. For example, in an aspect, the wireless communication device 1200, the processor 1205, the memory 1210, the multi-link Rx component 1215, or the reservation component 1230 may be configured to perform or may include means for performing the following operations: receiving a medium reservation message 710 on the first link 616 that reserves a TXOP 714 for the station. In some implementations, the medium reservation message is one of a CTS2Self message or a modified RTS message. In response to the modified RTS message, the reservation component 1230 may transmit a CTS message indicating the TXOP 714.

[0141] At block 1308, the process 1300 includes receiving a first physical protocol data unit (PPDU) on the first link 616 during the TXOP. For example, in an aspect, the wireless communication device 1200, the processor 1205, the memory 1210, the multi-link Rx component 1215, or the first receiving component 1240 may be configured to perform or may include means for receiving the first PPDU 614 on the first link 616 during the TXOP 714.

[0142] In block 1310, process 1300 includes receiving a second PPDU on the second link 626 during the TXOP. For example, in an aspect, wireless communication device 1200, processor 1205, memory 1210, multi-link Rx component 1215, or second receive component 1245 may be configured to, or may include means for, receiving the second PPDU 624 on the second link 626 during the TXOP 714. The start time and the end time of the first PPDU and the second PPDU are aligned.

[0143] Fig.14An example state transition diagram 1400 including different states for a wireless device utilizing a credit-based EDCA mechanism is shown. In state 1410, the wireless device may monitor the medium and update the NAV. In state 1420, the wireless device may wait for the DIFS to elapse. In state 1430, the wireless device may count down the RBO. In state 1440, the wireless device may transmit. The wireless device may transition from state 1410 to state 1420 when the packet queue has data (such as greater than 0) and the medium is not busy. The wireless device may transition from state 1420 to state 1430 when the DIFS has elapsed and the CCA and NAV are not set. The wireless device may obtain a new RBO. If the RBO adjustment component 950 did not previously set the RBO to 0, the residual value c may be 0. Otherwise, the residual value c may be equal to the previous RBO value. The wireless device may increase the new RBO by the residual value c multiplied by a weighting factor α. When the link that counts down to 0 wins the TXOP, the wireless device may transition from state 1430 to state 1440. If the RBO for another link is less than a threshold h, the wireless device may set the RBO for the other link to 0 and store the remaining RBO of the other link as a residual value c. When the transmission is complete, the wireless device may transition from state 1440 to state 1410. When CCA or NAV is set, the wireless device may transition from state 1420 or state 1430.

[0144] Some further example clauses

[0145] Various implementation examples are described in the following numbered clauses.

[0146] 1. A method for wireless communication by a wireless communication device, comprising:

[0147] determining that a first random backoff (RBO) for a first channel of a first link has counted down to zero;

[0148] determining that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero;

[0149] determining whether to wait for a second RBO before transmitting on the first link; and

[0150] At least a first physical protocol data unit (PPDU) is transmitted on the first link during a transmission opportunity (TXOP) that begins when the first RBO has been counted down to zero.

[0151] 2. The method of clause 1, further comprising:

[0152] In response to determining to wait for the second RBO, determining that the second RBO has been counted down to zero; and

[0153] A second PPDU is transmitted on the second link, wherein the start time and the end time of the first PPDU and the second PPDU are aligned.

[0154] 3. The method of clause 1 or 2, further comprising: transmitting a medium reservation message on the first link to reserve the TXOP.

[0155] 4. The method of clause 3, wherein the medium reservation message is one of a Clear to Send to Self (CTS2Self) message or a modified Request to Send (RTS) message.

[0156] 5. A method as described in clause 3 or 4, wherein the medium reservation message interrupts the second RBO for the second link, and the method further includes: restoring the second RBO after the medium reservation message.

[0157] 6. A method as in any of clauses 3-5, wherein determining whether to wait for the second RBO before transmitting on the first link is based on a probability of accessing the second link and an idle period on the first link between the medium reservation message and the expected availability of the second link.

[0158] 7. The method of any of clauses 3-6, wherein an access point (AP) refrains from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

[0159] 8. A method as in any of clauses 3-7, wherein the access point of the second link announces an EDCA set including second-stage enhanced distributed channel access (EDCA) parameters, the method further comprising: adjusting the second RBO based on the second-stage EDCA parameters in response to transmitting the medium reservation message.

[0160] 9. The method of any of clauses 3-8, wherein determining whether to wait for the second RBO before transmitting on the first link comprises: determining to transmit the first PPDU without waiting in response to determining that the second RBO is greater than a threshold.

[0161] 10. The method of any of clauses 1 or 3-8, wherein determining whether to wait for the second RBO before transmitting on the first link comprises: determining to transmit the first PPDU without waiting in response to determining that the second channel is blocked by a network allocation vector (NAV).

[0162] 11. The method of any of clauses 1 or 3-8, wherein determining whether to wait for a second RBO before transmitting on the first link comprises:

[0163] determining to wait for a second RBO before transmitting on the first link; and

[0164] A determination is made to transmit on the first link without waiting in response to determining that the second link is blocked.

[0165] 12. The method of clause 11, wherein determining that the second link is blocked comprises determining that a wait time has expired.

[0166] 13. The method of any of clauses 1-12, wherein the first RBO and the second RBO are initialized with the same value.

[0167] 14. The method of clause 1, further comprising:

[0168] Determining that the remaining countdown of the second RBO is less than a threshold value; and

[0169] When the second channel is idle, the remaining countdown of the second RBO is set to zero.

[0170] 15. The method of clause 14, further comprising:

[0171] selecting a new RBO for the second channel of the second link; and

[0172] The new RBO is increased based on the residual value of the second RBO.

[0173] 16. The method of clause 15, wherein increasing the new RBO based on the residual value of the second RBO comprises: multiplying the new RBO increased residual value by a configurable weighting factor.

[0174] 17. The method of clause 1, further comprising:

[0175] Adding an offset to a first RBO and a second RBO based on a configurable weighting factor, wherein transmitting at least a first PPDU on the first link during the TXOP includes: transmitting the first PPDU on the first link and transmitting the second PPDU on the second link in response to determining that the first RBO or the second RBO has been counted down to zero, wherein a start time and an end time of the first PPDU and the second PPDU are aligned.

[0176] 18. The method of clause 1, wherein determining whether to wait for a second RBO before transmitting on the first link comprises:

[0177] Determining to wait for a second RBO before transmitting on the first link;

[0178] resetting the first RBO in response to another device using the first channel; and

[0179] Wait for the first RBO and the second RBO to count down to zero.

[0180] 19. The method of clause 18, wherein resetting the first RBO comprises setting a value of the first RBO based on a remaining countdown of the second RBO.

[0181] 20. A method for wireless communication by a wireless access point (AP), comprising:

[0182] announcing a first enhanced distributed channel access (EDCA) set, the first EDCA set comprising first EDCA parameters for a first link;

[0183] announcing a second EDCA set, the second EDCA set including second EDCA parameters for the second link;

[0184] receiving a first physical protocol data unit (PPDU) from a station on a first link during a transmission opportunity (TXOP); and

[0185] A second PPDU is received from the station on a second link during the TXOP, wherein a start time of the first PPDU and an end time of the second PPDU are aligned.

[0186] 21. The method of clause 20, further comprising: receiving a medium reservation message on the first link reserving the TXOP for the station.

[0187] 22. The method of clause 21, wherein the medium reservation message is one of a Clear to Send to Self (CTS2Self) message or a modified Request to Send (RTS) message.

[0188] 23. The method of clause 21 or 22, further comprising: refraining from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

[0189] 24. A method as in any of clauses 20-23, wherein the second EDCA set includes: first-stage EDCA parameters to be used when the station has not yet mastered another channel, and second-stage EDCA parameters to be used when the station has mastered another channel, wherein a random backoff (RBO) range of the second-stage EDCA parameters includes a value that is smaller than the RBO range of the first-stage EDCA parameters.

[0190] 25. A wireless communication device, comprising:

[0191] at least one modem;

[0192] at least one processor communicatively coupled to the at least one modem; and

[0193] at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to:

[0194] determining that a first random backoff (RBO) for a first channel of a first link has counted down to zero;

[0195] determining that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero;

[0196] determining whether to wait for a second RBO before transmitting on the first link; and

[0197] At least a first physical protocol data unit (PPDU) is transmitted on the first link during a transmission opportunity (TXOP) that begins when the first RBO has been counted down to zero.

[0198] 26. The wireless communication device of clause 25, wherein the processor readable code is configured to:

[0199] In response to determining to wait for the second RBO, determining that the second RBO has been counted down to zero; and

[0200] A second PPDU is transmitted on the second link, wherein the start time and the end time of the first PPDU and the second PPDU are aligned.

[0201] 27. The wireless communication device of clause 25, wherein the processor readable code is configured to: transmit a medium reservation message reserving the TXOP on the first link.

[0202] 28. The wireless communication device of clause 27, wherein the medium reservation message is one of a Clear to Send to Self (CTS2Self) message or a modified Request to Send (RTS) message.

[0203] 29. The wireless communication device of clause 27 or 28, wherein the medium reservation message interrupts a second RBO for the second link, the wireless communication device further comprising: restoring the second RBO after the medium reservation message.

[0204] 30 A wireless communication device as in clause 27 or 28, wherein the processor readable code is configured to determine whether to wait for a second RBO before transmitting on the first link based on a probability of accessing the second link and an idle period on the first link between the medium reservation message and the expected availability of the second link.

[0205] 31. The wireless communications device of clause 27, wherein the access point refrains from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

[0206] 32. A wireless communication device as in any one of clauses 27-31, wherein the access point announcement of the second link includes an EDCA set of second-stage enhanced distributed channel access (EDCA) parameters, and the wireless communication device further includes: adjusting the second RBO based on the second-stage EDCA parameters in response to transmitting the medium reservation message.

[0207] 33. The wireless communication device of any of clauses 27-32, wherein the processor readable code for determining whether to wait for the second RBO before transmitting on the first link comprises: processor readable code for determining to transmit the first PPDU without waiting in response to determining that the second RBO is greater than a threshold.

[0208] 34. A wireless communication device as in any of clauses 27 or 29-33, wherein the processor-readable code for determining whether to wait for the second RBO before transmitting on the first link includes: processor-readable code for determining to transmit the first PPDU without waiting in response to determining that the second channel is blocked by the network allocation vector (NAV).

[0209] 35. The wireless communication device of any of clauses 27 or 29-34, wherein the processor readable code for determining whether to wait for a second RBO before transmitting on the first link comprises processor readable code for:

[0210] determining to wait for a second RBO before transmitting on the first link; and

[0211] A determination is made to transmit on the first link without waiting in response to determining that the second link is blocked.

[0212] 36. The wireless communication device of clause 35, wherein the processor readable code for determining that the second link is blocked comprises processor readable code for determining that a wait time has expired.

[0213] 37. The wireless communication device of any of clauses 27-36, wherein the first RBO and the second RBO are initialized with the same value.

[0214] 38. The wireless communication device of clause 25, wherein the processor readable code is configured to:

[0215] Determining that the remaining countdown of the second RBO is less than a threshold value; and

[0216] When the second channel is idle, the remaining countdown of the second RBO is set to zero.

[0217] 39. The wireless communication device of clause 38, wherein the processor readable code is configured to:

[0218] selecting a new RBO for the second channel of the second link; and

[0219] The new RBO is increased based on the residual value of the second RBO.

[0220] 40. The wireless communication device of clause 39, wherein the processor readable code for increasing the new RBO based on the residual value of the second RBO comprises: processor readable code for increasing the new RBO by multiplying the residual value by a configurable weighting factor.

[0221] 41. The wireless communication device of clause 25, wherein the processor readable code is configured to:

[0222] An offset is added to a first RBO and a second RBO based on a configurable weighting factor, wherein processor-readable code for transmitting at least a first PPDU on a first link during the TXOP includes: processor-readable code for transmitting a first PPDU on the first link and a second PPDU on the second link in response to determining that the first RBO or the second RBO has been counted down to zero, wherein a start time and an end time of the first PPDU and the second PPDU are aligned.

[0223] 42. The wireless communication device of clause 25, wherein the processor readable code is configured to:

[0224] Determining to wait for a second RBO before transmitting on the first link;

[0225] resetting the first RBO in response to another device using the first channel; and

[0226] Wait for the first RBO and the second RBO to count down to zero.

[0227] 43. The wireless communication device of clause 42, wherein the processor readable code is configured to: set the value of the first RBO based on a remaining countdown of the second RBO.

[0228] 44. A wireless access point, comprising:

[0229] at least one modem;

[0230] at least one processor communicatively coupled to the at least one modem; and

[0231] at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to:

[0232] announcing a first enhanced distributed channel access (EDCA) set, the first EDCA set comprising first EDCA parameters for a first link;

[0233] announcing a second EDCA set, the second EDCA set including second EDCA parameters for the second link;

[0234] receiving a first physical protocol data unit (PPDU) from a station on a first link during a transmission opportunity (TXOP); and

[0235] A second PPDU is received from the station on a second link during the TXOP, wherein a start time of the first PPDU and an end time of the second PPDU are aligned.

[0236] 45. The wireless access point of clause 44, wherein the processor readable code is configured to: receive a medium reservation message on the first link reserving the TXOP for the station.

[0237] 46. ​​The wireless access point of clause 45, wherein the medium reservation message is one of a Clear to Send to Self (CTS2Self) message or a modified Request to Send (RTS) message.

[0238] 47. The wireless access point of clause 45 or 46, wherein the processor readable code is configured to: refrain from transmitting a downlink PPDU on the second link during the TXOP in response to the medium reservation message.

[0239] 48. A wireless access point as in any of clauses 44-47, wherein the second EDCA set includes: first-stage EDCA parameters to be used when the station has not yet mastered another channel, and second-stage EDCA parameters to be used when the station has mastered another channel, wherein a random backoff (RBO) range of the second-stage EDCA parameters includes a value that is smaller than the RBO range of the first-stage EDCA parameters.

[0240] 49. An apparatus for wireless communication by a wireless communication device, comprising:

[0241] means for determining that a first random backoff (RBO) for a first channel of a first link has counted down to zero;

[0242] means for determining that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero;

[0243] means for determining whether to wait for a second RBO before transmitting on the first link; and

[0244] Means for transmitting at least a first physical protocol data unit (PPDU) on a first link during a transmission opportunity (TXOP) that begins when a first RBO has been counted down to zero.

[0245] 50. The device of clause 49, further comprising:

[0246] means for determining that the second RBO has been counted down to zero in response to determining that the second RBO is to be waited; and

[0247] Means for transmitting a second PPDU on a second link, wherein a start time and an end time of the first PPDU and the second PPDU are aligned.

[0248] 51. The apparatus of clause 49 or 50, further comprising: means for transmitting a medium reservation message reserving the TXOP on the first link.

[0249] 52. The apparatus of clause 51, wherein the medium reservation message is one of a clear to send to self (CTS2Self) message or a modified request to send (RTS) message.

[0250] 53. The apparatus of clause 51 or 52, wherein the medium reservation message interrupts a second RBO for the second link, the method further comprising: restoring the second RBO after the medium reservation message.

[0251] 54. An apparatus as in any of clauses 51-53, wherein the means for determining whether to wait for the second RBO before transmitting on the first link is based on a probability of accessing the second link and an idle period on the first link between the medium reservation message and an expected availability of the second link.

[0252] 55. The apparatus of any of clauses 51-54, wherein the access point refrains from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

[0253] 56. An apparatus as in any one of clauses 51-55, wherein the access point announcement for the second link includes an EDCA set of second-stage enhanced distributed channel access (EDCA) parameters, the method further comprising: a device for adjusting the second RBO based on the second-stage EDCA parameters in response to transmitting the medium reservation message.

[0254] 57. The apparatus of any of clauses 49 or 51-56, wherein the means for determining whether to wait for the second RBO before transmitting on the first link is configured to: determine to transmit the first PPDU without waiting in response to determining that the second RBO is greater than a threshold.

[0255] 58. An apparatus as in any of clauses 49 or 51-56, wherein the means for determining whether to wait for the second RBO before transmitting on the first link is configured to: determine to transmit the first PPDU without waiting in response to determining that the second channel is blocked by a network allocation vector (NAV).

[0256] 59. The apparatus of any of clauses 49 or 51-56, wherein the means for determining whether to wait for a second RBO before transmitting on the first link is configured to:

[0257] determining to wait for a second RBO before transmitting on the first link; and

[0258] A determination is made to transmit on the first link without waiting in response to determining that the second link is blocked.

[0259] 60. The apparatus of clause 59, wherein the means for determining that the second link is blocked is configured to: determine that a wait time has expired.

[0260] 61. The apparatus of any of clauses 49 or 60, wherein the first RBO and the second RBO are initialized with the same value.

[0261] 62. The equipment of clause 49, further comprising:

[0262] means for determining that the remaining countdown of the second RBO is less than a threshold value; and

[0263] Means for setting the remaining countdown of the second RBO to zero when the second channel is idle.

[0264] 63. The apparatus of clause 61, further comprising:

[0265] means for selecting a new RBO for a second channel of a second link; and

[0266] Means for increasing the new RBO based on the residual value of the second RBO.

[0267] 64. The apparatus of clause 63, wherein the means for increasing the new RBO based on the residual value of the second RBO is configured to: increase the new RBO by multiplying the residual value by a configurable weighting factor.

[0268] 65. The equipment of clause 49, further comprising:

[0269] An apparatus for adding an offset to a first RBO and a second RBO based on a configurable weighting factor, wherein transmitting at least a first PPDU on a first link during the TXOP comprises transmitting the first PPDU on the first link and transmitting the second PPDU on the second link in response to determining that the first RBO or the second RBO has been counted down to zero, wherein a start time and an end time of the first PPDU and the second PPDU are aligned.

[0270] 66. The apparatus of clause 49, wherein the means for determining whether to wait for the second RBO before transmitting on the first link is configured to:

[0271] Determining to wait for a second RBO before transmitting on the first link;

[0272] resetting the first RBO in response to another device using the first channel; and

[0273] Wait for the first RBO and the second RBO to count down to zero.

[0274] 67. The apparatus of clause 49, wherein the means for determining whether to wait for the second RBO before transmitting on the first link is configured to set the value of the first RBO based on a remaining countdown of the second RBO.

[0275] 68. A device for wireless communication by a wireless access point, comprising:

[0276] means for announcing a first enhanced distributed channel access (EDCA) set, the first EDCA set comprising first EDCA parameters for a first link;

[0277] means for announcing a second EDCA set, the second EDCA set comprising second EDCA parameters for a second link;

[0278] means for receiving a first physical protocol data unit (PPDU) from a station on a first link during a transmission opportunity (TXOP); and

[0279] Means for receiving a second PPDU from the station on a second link during the TXOP, wherein a start time and an end time of the first PPDU and the second PPDU are aligned.

[0280] 69. The apparatus of clause 68, further comprising: means for receiving a medium reservation message on the first link reserving the TXOP for the station.

[0281] 70. The apparatus of clause 69, wherein the medium reservation message is one of a clear to send to self (CTS2Self) message or a modified request to send (RTS) message.

[0282] 71. The apparatus of clause 69 or 70, further comprising: means for refraining from transmitting a downlink PPDU on the second link during the TXOP in response to the medium reservation message.

[0283] 72. An apparatus as in any of clauses 68-71, wherein the second EDCA set includes: first-stage EDCA parameters to be used when the station has not yet mastered another channel, and second-stage EDCA parameters to be used when the station has mastered another channel, wherein a random backoff (RBO) range of the second-stage EDCA parameters includes a value that is smaller than the RBO range of the first-stage EDCA parameters.

[0284] 73. A non-transitory computer readable medium comprising stored instructions for wireless communication by a wireless communication device, the stored instructions executable by a processor to:

[0285] determining that a first random backoff (RBO) for a first channel of a first link has counted down to zero;

[0286] determining that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero;

[0287] determining whether to wait for a second RBO before transmitting on the first link; and

[0288] At least a first physical protocol data unit (PPDU) is transmitted on the first link during a transmission opportunity (TXOP) that begins when the first RBO has been counted down to zero.

[0289] 74. The non-transitory computer readable medium of clause 73, wherein the stored instructions include instructions for:

[0290] In response to determining to wait for the second RBO, determining that the second RBO has been counted down to zero; and

[0291] A second PPDU is transmitted on the second link, wherein the start time and the end time of the first PPDU and the second PPDU are aligned.

[0292] 75. The non-transitory computer-readable medium of clause 73 or 74, wherein the stored instructions include instructions for transmitting a medium reservation message reserving the TXOP on the first link.

[0293] 76. The non-transitory computer-readable medium of clause 75, wherein the medium reservation message is one of a Clear Send to Self (CTS2Self) message or a modified Request to Send (RTS) message.

[0294] 77. The non-transitory computer-readable medium of clause 75, wherein the medium reservation message interrupts the second RBO for the second link, the non-transitory computer-readable medium further comprising: restoring the second RBO after the medium reservation message.

[0295] 78. A non-transitory computer-readable medium as in any of clauses 75-78, wherein the stored instructions for determining whether to wait for a second RBO before transmitting on a first link are based on a probability of accessing the second link and an idle period on the first link between the medium reservation message and the expected availability of the second link.

[0296] 79. The non-transitory computer-readable medium of any of clauses 75-79, wherein the access point refrains from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

[0297] 80. A non-transitory computer-readable medium as in any of clauses 75-79, wherein the access point announcement for the second link includes an EDCA set of second-stage enhanced distributed channel access (EDCA) parameters, the non-transitory computer-readable medium further comprising: stored instructions for adjusting the second RBO based on the second-stage EDCA parameters in response to transmitting the medium reservation message.

[0298] 81. A non-transitory computer-readable medium as in any of clauses 73 or 75-80, wherein the stored instructions for determining whether to wait for the second RBO before transmitting on the first link include: stored instructions for determining to transmit the first PPDU without waiting in response to determining that the second RBO is greater than a threshold.

[0299] 82. A non-transitory computer-readable medium as in any of clauses 73 or 75-80, wherein the stored instructions for determining whether to wait for the second RBO before transmitting on the first link include: stored instructions for transmitting the first PPDU without waiting in response to determining that the second channel is blocked by a network allocation vector (NAV).

[0300] 83. The non-transitory computer-readable medium of any of clauses 73 or 75-80, wherein the stored instructions for determining whether to wait for the second RBO before transmitting on the first link comprise stored instructions for:

[0301] determining to wait for a second RBO before transmitting on the first link; and

[0302] A determination is made to transmit on the first link without waiting in response to determining that the second link is blocked.

[0303] 84. The non-transitory computer-readable medium of clause 83, wherein the stored instructions for determining that the second link is blocked include stored instructions for determining that a wait time has expired.

[0304] 85. The non-transitory computer-readable medium of any of clauses 73-84, wherein the first RBO and the second RBO are initialized with the same value.

[0305] 86. The non-transitory computer-readable medium of clause 73, wherein the stored instructions include instructions for:

[0306] Determining that the remaining countdown of the second RBO is less than a threshold value; and

[0307] When the second channel is idle, the remaining countdown of the second RBO is set to zero.

[0308] 87. The non-transitory computer readable medium of clause 86, wherein the stored instructions include instructions for:

[0309] selecting a new RBO for the second channel of the second link; and

[0310] The new RBO is increased based on the residual value of the second RBO.

[0311] 88. The non-transitory computer-readable medium of clause 87, wherein the stored instructions for increasing the new RBO based on the residual value of the second RBO include: stored instructions for increasing the new RBO by multiplying the residual value by a configurable weighting factor.

[0312] 89. The non-transitory computer-readable medium of clause 73, wherein the stored instructions include instructions for:

[0313] An offset is added to a first RBO and a second RBO based on a configurable weighting factor, wherein the stored instructions for transmitting at least a first PPDU on the first link during the TXOP include: stored instructions for transmitting a first PPDU on the first link and a second PPDU on the second link in response to determining that the first RBO or the second RBO has been counted down to zero, wherein a start time and an end time of the first PPDU and the second PPDU are aligned.

[0314] 90. The non-transitory computer-readable medium of clause 73, wherein the stored instructions include instructions for:

[0315] Determining to wait for a second RBO before transmitting on the first link;

[0316] resetting the first RBO in response to another device using the first channel; and

[0317] Wait for the first RBO and the second RBO to count down to zero.

[0318] 91. The non-transitory computer-readable medium of clause 76, wherein the stored instructions include instructions for setting a value of the first RBO based on a remaining countdown of the second RBO.

[0319] 92. A non-transitory computer readable medium comprising stored instructions for wireless communications by a wireless access point, the stored instructions executable by a processor to:

[0320] announcing a first enhanced distributed channel access (EDCA) set, the first EDCA set comprising first EDCA parameters for a first link;

[0321] announcing a second EDCA set, the second EDCA set including second EDCA parameters for the second link;

[0322] receiving a first physical protocol data unit (PPDU) from a station on a first link during a transmission opportunity (TXOP); and

[0323] A second PPDU is received from the station on a second link during the TXOP, wherein a start time of the first PPDU and an end time of the second PPDU are aligned.

[0324] 93. The non-transitory computer-readable medium of clause 92, wherein the stored instructions are configured to: receive a medium reservation message on the first link reserving the TXOP for the station.

[0325] 94. The non-transitory computer-readable medium of clause 93, wherein the medium reservation message is one of a Clear Send to Self (CTS2Self) message or a modified Request to Send (RTS) message.

[0326] 95. The non-transitory computer-readable medium of clause 93 or 94, wherein the stored instructions are configured to: refrain from transmitting a downlink PPDU on the second link during the TXOP in response to the medium reservation message.

[0327] 96. A non-transitory computer-readable medium as in any of clauses 92-95, wherein the second EDCA set comprises: first-stage EDCA parameters to be used when the station has not yet mastered another channel, and second-stage EDCA parameters to be used when the station has mastered another channel, wherein a random backoff (RBO) range of the second-stage EDCA parameters comprises a value that is smaller than the RBO range of the first-stage EDCA parameters.

[0328] As used herein, "or" is intended to be interpreted in an inclusive sense unless otherwise expressly indicated. For example, "a or b" may include only a, only b, or a combination of a and b. As used herein, a phrase that refers to "at least one of" 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 cover the following possibilities: only a, only b, only c, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b, and c.

[0329] 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.

[0330] The hardware and data processing apparatus for implementing the various illustrative logics, logic blocks, modules, and circuits described in conjunction with the aspects disclosed herein may be implemented or executed with a general purpose single-chip or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in cooperation with a DSP core, or any other such configuration. In some implementations, specific processes and methods may be performed by circuit systems dedicated to a given function.

[0331] In one or more aspects, the functions described may be implemented in hardware, digital electronic circuitry, computer software, firmware (including the structures disclosed in this specification and their structural equivalents), or in any combination thereof. Implementations of the subject matter described in this specification may also be implemented as one or more computer programs, i.e., one or more modules of computer program instructions encoded on a computer storage medium for execution by a data processing apparatus or for controlling the operation of a data processing apparatus.

[0332] If implemented in software, each function can be stored on a computer-readable medium or transmitted therethrough as one or more instructions or codes. The process of the method or algorithm disclosed herein can be implemented in a processor executable software module that can reside on a computer-readable medium. Computer-readable media include both computer storage media and communication media, including any medium that can be implemented to transfer a computer program from one place to another. Storage media can be any available medium that can be accessed by a computer. As an example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage devices, or any other medium that can be used to store the desired program code in the form of an instruction or data structure and can be accessed by a computer. Any connection may also be appropriately referred to as a computer-readable medium. As used herein, disks and discs include compact discs (CDs), laser discs, optical discs, digital versatile discs (DVDs), floppy disks and blue-ray discs, wherein disks often reproduce data magnetically and discs reproduce data optically with lasers. The above combination should also be included in the scope of computer-readable media. Additionally, the operations of a method or algorithm may reside as one or any combination or set of codes and instructions on a machine-readable medium and a computer-readable medium, which may be incorporated into a computer program product.

[0333] Various modifications to the implementations described in this disclosure may be apparent to those of ordinary skill in the art, and the universal principles defined herein may be applied to other implementations without departing from the spirit or scope of the disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but should be granted the widest scope consistent with the disclosure, the principles and novel features disclosed herein.

[0334] Additionally, various features described in this specification in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented in multiple implementations separately or in any suitable subcombination. Thus, while features may be described above as functioning in a particular combination and even initially claimed as such, one or more features from a claimed combination may in some cases be removed from the combination, and a claimed combination may be directed to a subcombination, or a variation of a subcombination.

[0335] Similarly, although operations are depicted in a particular order in the accompanying drawings, this should not be understood as requiring such operations to be performed in the particular order shown or in a sequential order, or to perform all the illustrated operations to achieve the desired result. In addition, the accompanying drawings may schematically depict one or more example processes in the form of a flow chart or a flow diagram. However, other operations not depicted may be incorporated into the schematically illustrated example processes. For example, one or more additional operations may be performed before, after, simultaneously, or between any illustrated operations. In some environments, multitasking and parallel processing may be advantageous. In addition, the separation of various system components in the above implementations 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 communication device, comprising: Determining that a first random backoff RBO for a first channel of a first link has counted down to zero; determining that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero; determining whether to wait for the second RBO before transmitting on the first link; as well as At least a first physical protocol data unit PPDU is transmitted on the first link during a transmission opportunity TXOP that begins when the first RBO has been counted down to zero.

2. The method of claim 1, further comprising: In response to determining to wait for the second RBO, determining that the second RBO has been counted down to zero; as well as A second PPDU is transmitted over the second link, wherein a start time and an end time of the first PPDU and the second PPDU are aligned.

3. The method of claim 1, further comprising: A medium reservation message reserving the TXOP is transmitted on the first link.

4. The method of claim 3, wherein the medium reservation message is one of a Clear to Send (CTS2Self) message or a modified Request to Send (RTS) message.

5. The method of claim 3, wherein the medium reservation message interrupts the second RBO for the second link, the method further comprising: The second RBO is restored after the medium reservation message.

6. The method of claim 3, wherein determining whether to wait for the second RBO before transmitting on the first link is based on a probability of accessing the second link and an idle period on the first link between the medium reservation message and the expected availability of the second link.

7. The method of claim 3, wherein an access point (AP) refrains from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

8. The method of claim 3, wherein the access point for the second link announces an EDCA set including second phase Enhanced Distributed Channel Access (EDCA) parameters, the method further comprising: The second RBO is adjusted based on the second stage EDCA parameters in response to transmitting the medium reservation message.

9. The method of claim 1 , wherein determining whether to wait for the second RBO before transmitting on the first link comprises: In response to determining that the second RBO is greater than a threshold, it is determined that the first PPDU is to be transmitted without waiting.

10. The method of claim 1, wherein determining whether to wait for the second RBO before transmitting on the first link comprises: In response to determining that the second channel is blocked by a network allocation vector NAV, determining to transmit the first PPDU without waiting.

11. The method of claim 1 , wherein determining whether to wait for the second RBO before transmitting on the first link comprises: determining to wait for the second RBO before transmitting on the first link; as well as A determination is made to transmit on the first link without waiting in response to determining that the second link is blocked.

12. The method of claim 11, wherein determining that the second link is blocked comprises: Make sure the wait time has expired.

13. The method of claim 1, wherein the first RBO and the second RBO are initialized with the same value.

14. The method of claim 1, further comprising: Determining that the remaining countdown of the second RBO is less than a threshold; as well as The remaining countdown of the second RBO is set to zero when the second channel is idle.

15. The method of claim 14, further comprising: selecting a new RBO for the second channel of the second link; as well as The new RBO is increased based on the residual value of the second RBO.

16. The method of claim 15, wherein increasing the new RBO based on the residual value of the second RBO comprises: The new RBO is increased by the residual value multiplied by a configurable weighting factor.

17. The method of claim 1, further comprising: Adding an offset to the first RBO and the second RBO based on a configurable weighting factor, wherein transmitting at least the first PPDU on the first link during the TXOP includes: transmitting the first PPDU on the first link and transmitting the second PPDU on the second link in response to determining that the first RBO or the second RBO has been counted down to zero, wherein the start time and the end time of the first PPDU and the second PPDU are aligned.

18. The method of claim 1, wherein determining whether to wait for the second RBO before transmitting on the first link comprises: determining to wait for the second RBO before transmitting on the first link; resetting the first RBO in response to another device using the first channel; as well as Wait for the first RBO and the second RBO to count down to zero.

19. The method of claim 18, wherein resetting the first RBO comprises: The value of the first RBO is set based on the remaining countdown of the second RBO.

20. A method for wireless communication by a wireless access point AP, comprising: announcing a first enhanced distributed channel access EDCA set, wherein the first EDCA set includes first EDCA parameters for a first link; announcing a second EDCA set, the second EDCA set comprising second EDCA parameters for a second link; receiving a first physical protocol data unit PPDU from a station on said first link during a transmission opportunity TXOP; as well as A second PPDU is received from the station on the second link during the TXOP, wherein start times and end times of the first PPDU and the second PPDU are aligned.

21. The method of claim 20, further comprising: A medium reservation message is received on the first link reserving the TXOP for the station.

22. The method of claim 21, wherein the medium reservation message is one of a Clear to Send (CTS2Self) message or a modified Request to Send (RTS) message.

23. The method of claim 21, further comprising: Transmitting downlink PPDUs on the second link during the TXOP is refrained in response to the medium reservation message.

24. The method of claim 20, wherein the second EDCA set comprises: First-stage EDCA parameters to be used when the station has not yet mastered another channel, and second-stage EDCA parameters to be used when the station has mastered another channel, wherein a random backoff RBO range of the second-stage EDCA parameters includes a value smaller than the RBO range of the first-stage EDCA parameters.

25. A wireless communication device, comprising: at least one modem; at least one processor communicatively coupled to the at least one modem; as well as at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to: Determining that a first random backoff RBO for a first channel of a first link has counted down to zero; determining that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero; determining whether to wait for the second RBO before transmitting on the first link; as well as At least a first physical protocol data unit PPDU is transmitted on the first link during a transmission opportunity TXOP that begins when the first RBO has been counted down to zero.

26. The wireless communication device of claim 25, wherein the processor readable code is configured to: In response to determining to wait for the second RBO, determining that the second RBO has been counted down to zero; and A second PPDU is transmitted over the second link, wherein a start time and an end time of the first PPDU and the second PPDU are aligned.

27. The wireless communication device of claim 25, wherein the processor readable code is configured to transmit a medium reservation message reserving the TXOP on the first link.

28. The wireless communication device of claim 27, wherein the medium reservation message is one of a Clear to Send (CTS2Self) message or a modified Request to Send (RTS) message.

29. The wireless communication device of claim 27, wherein the medium reservation message interrupts the second RBO for the second link, wherein the processor readable code is further configured to: restore the second RBO after the medium reservation message.

30. A wireless communication device as described in claim 27, wherein the processor readable code configured to determine whether to wait for the second RBO before transmitting on the first link is based on the probability of accessing the second link and an idle period on the first link between the medium reservation message and the expected availability of the second link.

31. The wireless communication device of claim 27, wherein an access point refrains from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

32. The wireless communication device of claim 27, wherein the access point announcement for the second link includes an EDCA set of second phase enhanced distributed channel access EDCA parameters, wherein the processor readable code is further configured to adjust the second RBO based on the second phase EDCA parameters in response to transmitting the medium reservation message.

33. The wireless communication device of claim 25, wherein the processor readable code for determining whether to wait for the second RBO before transmitting on the first link comprises: Processor readable code for determining to transmit the first PPDU without waiting in response to determining that the second RBO is greater than a threshold.

34. The wireless communication device of claim 25, wherein the processor readable code for determining whether to wait for the second RBO before transmitting on the first link comprises: Processor readable code for determining to transmit the first PPDU without waiting in response to determining that the second channel is blocked by a network allocation vector NAV.

35. The wireless communication device of claim 25, wherein the processor readable code for determining whether to wait for the second RBO before transmitting on the first link comprises processor readable code for: determining to wait for the second RBO before transmitting on the first link; and A determination is made to transmit on the first link without waiting in response to determining that the second link is blocked.

36. The wireless communication device of claim 35, wherein the processor readable code for determining that the second link is blocked comprises: Processor readable code for determining that a wait time has expired.

37. The wireless communication device of claim 25, wherein the first RBO and the second RBO are initialized with the same value.

38. The wireless communication device of claim 25, wherein the processor readable code is configured to: Determining that the remaining countdown of the second RBO is less than a threshold; and The remaining countdown of the second RBO is set to zero when the second channel is idle.

39. The wireless communication device of claim 38, wherein the processor readable code is configured to: selecting a new RBO for the second channel of the second link; and The new RBO is increased based on the residual value of the second RBO.

40. The wireless communication device of claim 39, wherein the processor readable code for increasing the new RBO based on the residual value of the second RBO comprises: Processor readable code for increasing the new RBO by the residual value multiplied by a configurable weighting factor.

41. The wireless communication device of claim 25, wherein the processor readable code is configured to: adding an offset to the first RBO and the second RBO based on a configurable weighting factor, wherein the processor readable code for transmitting at least the first PPDU on the first link during the TXOP comprises: Processor readable code for transmitting the first PPDU on the first link and transmitting the second PPDU on the second link in response to determining that the first RBO or the second RBO has been counted down to zero, wherein the start time and the end time of the first PPDU and the second PPDU are aligned.

42. The wireless communication device of claim 25, wherein the processor readable code is configured to: determining to wait for the second RBO before transmitting on the first link; resetting the first RBO in response to another device using the first channel; and Wait for the first RBO and the second RBO to count down to zero.

43. The wireless communication device of claim 42, wherein the processor readable code is configured to set a value of the first RBO based on the remaining countdown of the second RBO.

44. A wireless access point, comprising: at least one modem; at least one processor communicatively coupled to the at least one modem; as well as at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor in conjunction with the at least one modem, is configured to: announcing a first enhanced distributed channel access EDCA set, wherein the first EDCA set includes first EDCA parameters for a first link; announcing a second EDCA set, the second EDCA set comprising second EDCA parameters for a second link; receiving a first physical protocol data unit PPDU from a station on said first link during a transmission opportunity TXOP; as well as A second PPDU is received from the station on the second link during the TXOP, wherein start times and end times of the first PPDU and the second PPDU are aligned.

45. The wireless access point of claim 44, wherein the processor readable code is configured to receive a medium reservation message on the first link reserving the TXOP for the station.

46. ​​The wireless access point of claim 45, wherein the medium reservation message is one of a Clear to Send (CTS2Self) message or a modified Request to Send (RTS) message.

47. The wireless access point of claim 45, wherein the processor readable code is configured to refrain from transmitting a downlink PPDU on the second link during the TXOP in response to the medium reservation message.

48. The wireless access point of claim 44, wherein the second EDCA set comprises: First-stage EDCA parameters to be used when the station has not yet mastered another channel, and second-stage EDCA parameters to be used when the station has mastered another channel, wherein a random backoff RBO range of the second-stage EDCA parameters includes a value smaller than the RBO range of the first-stage EDCA parameters.

49. An apparatus for wireless communication by a wireless communication device, comprising: means for determining that a first random backoff RBO for a first channel of a first link has counted down to zero; means for determining that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero; means for determining whether to wait for the second RBO before transmitting on the first link; as well as Means for transmitting at least a first physical protocol data unit (PPDU) on the first link during a transmission opportunity (TXOP) that begins when the first RBO has been counted down to zero.

50. The apparatus of claim 49, further comprising: means for determining that the second RBO has been counted down to zero in response to determining that the second RBO is to be waited; as well as Means for transmitting a second PPDU on the second link, wherein a start time and an end time of the first PPDU and the second PPDU are aligned.

51. The apparatus of claim 49, further comprising: Means for transmitting a medium reservation message reserving the TXOP on the first link.

52. The apparatus of claim 51, wherein the medium reservation message is one of a Clear to Send (CTS2Self) message or a modified Request to Send (RTS) message.

53. The apparatus of claim 51, wherein the medium reservation message interrupts the second RBO for the second link, the apparatus further comprising: Means for recovering the second RBO after the medium reservation message.

54. An apparatus as described in claim 51, wherein the device for determining whether to wait for the second RBO before transmitting on the first link is based on the probability of accessing the second link and the idle period on the first link between the medium reservation message and the expected availability of the second link.

55. The apparatus of claim 51, wherein an access point refrains from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

56. The apparatus of claim 51, wherein the access point for the second link announces an EDCA set including second phase Enhanced Distributed Channel Access (EDCA) parameters, the apparatus further comprising: Means for adjusting the second RBO based on the second stage EDCA parameters in response to transmitting the medium reservation message.

57. The apparatus of claim 49, wherein the means for determining whether to wait for the second RBO before transmitting on the first link is configured to determine to transmit the first PPDU without waiting in response to determining that the second RBO is greater than a threshold.

58. The apparatus of claim 49, wherein the means for determining whether to wait for the second RBO before transmitting on the first link is configured to determine to transmit the first PPDU without waiting in response to determining that the second channel is blocked by a network allocation vector NAV.

59. The apparatus of claim 49, wherein the means for determining whether to wait for the second RBO before transmitting on the first link is configured to: determining to wait for the second RBO before transmitting on the first link; and A determination is made to transmit on the first link without waiting in response to determining that the second link is blocked.

60. The apparatus of claim 59, wherein the means for determining that the second link is blocked is configured to determine that a wait time has expired.

61. The apparatus of claim 49, wherein the first RBO and the second RBO are initialized with the same value.

62. The apparatus of claim 49, further comprising: means for determining that the remaining countdown of the second RBO is less than a threshold; as well as Means for setting the remaining countdown of the second RBO to zero when the second channel is idle.

63. The apparatus of claim 61, further comprising: means for selecting a new RBO for said second channel of said second link; as well as Means for increasing the new RBO based on the residual value of the second RBO.

64. The apparatus of claim 63, wherein the means for increasing the new RBO based on the residual value of the second RBO is configured to increase the new RBO by multiplying the residual value by a configurable weighting factor.

65. The apparatus of claim 49, further comprising: A device for adding an offset to the first RBO and the second RBO based on a configurable weighting factor, wherein transmitting at least the first PPDU on the first link during the TXOP includes: transmitting the first PPDU on the first link and transmitting the second PPDU on the second link in response to determining that the first RBO or the second RBO has been counted down to zero, wherein the start time and the end time of the first PPDU and the second PPDU are aligned.

66. The apparatus of claim 49, wherein the means for determining whether to wait for the second RBO before transmitting on the first link is configured to: determining to wait for the second RBO before transmitting on the first link; resetting the first RBO in response to another device using the first channel; as well as Wait for the first RBO and the second RBO to count down to zero.

67. The apparatus of claim 49, wherein the means for determining whether to wait for the second RBO before transmitting on the first link is configured to set a value of the first RBO based on the remaining countdown of the second RBO.

68. A device for wireless communication by a wireless access point, comprising: means for announcing a first enhanced distributed channel access (EDCA) set, the first EDCA set comprising first EDCA parameters for a first link; means for announcing a second EDCA set, the second EDCA set comprising second EDCA parameters for a second link; means for receiving a first physical protocol data unit (PPDU) from a station on said first link during a transmission opportunity (TXOP); as well as means for receiving a second PPDU from the station on the second link during the TXOP, wherein start times and end times of the first PPDU and the second PPDU are aligned.

69. The apparatus of claim 68, further comprising: Means for receiving a medium reservation message on the first link reserving the TXOP for the station.

70. The apparatus of claim 69, wherein the medium reservation message is one of a Clear to Send (CTS2Self) message or a modified Request to Send (RTS) message.

71. The apparatus of claim 69, further comprising: means for refraining from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

72. The apparatus of claim 68, wherein the second EDCA set comprises: First-stage EDCA parameters to be used when the station has not yet mastered another channel, and second-stage EDCA parameters to be used when the station has mastered another channel, wherein a random backoff RBO range of the second-stage EDCA parameters includes a value smaller than the RBO range of the first-stage EDCA parameters.

73. A non-transitory computer readable medium comprising stored instructions for wireless communications by a wireless communications device, the stored instructions executable by a processor to: Determining that a first random backoff RBO for a first channel of a first link has counted down to zero; determining that a second RBO for a second channel of a second link has a remaining countdown when the first RBO has been counted down to zero; determining whether to wait for the second RBO before transmitting on the first link; as well as At least a first physical protocol data unit PPDU is transmitted on the first link during a transmission opportunity TXOP that begins when the first RBO has been counted down to zero.

74. The non-transitory computer readable medium of claim 73, wherein the stored instructions include instructions for: In response to determining to wait for the second RBO, determining that the second RBO has been counted down to zero; and A second PPDU is transmitted over the second link, wherein a start time and an end time of the first PPDU and the second PPDU are aligned.

75. The non-transitory computer readable medium of claim 73, wherein the stored instructions include: Instructions for transmitting a medium reservation message reserving the TXOP on the first link.

76. The non-transitory computer-readable medium of claim 75, wherein the medium reservation message is one of a Clear-To-Self (CTS2Self) message or a modified Request-To-Send (RTS) message.

77. The non-transitory computer readable medium of claim 75, wherein the medium reservation message interrupts the second RBO for the second link, wherein the stored instructions further comprise: Instructions for restoring the second RBO after the medium reservation message.

78. A non-transitory computer-readable medium as described in claim 75, wherein the stored instructions for determining whether to wait for the second RBO before transmitting on the first link are based on a probability of accessing the second link and an idle period on the first link between the medium reservation message and the expected availability of the second link.

79. The non-transitory computer-readable medium of claim 75, wherein the access point refrains from transmitting downlink PPDUs on the second link during the TXOP in response to the medium reservation message.

80. The non-transitory computer readable medium of claim 75, wherein the access point for the second link announces an EDCA set comprising second phase Enhanced Distributed Channel Access (EDCA) parameters, wherein the stored instructions further comprise: Instructions for adjusting the second RBO based on the second phase EDCA parameters in response to transmitting the medium reservation message.

81. The non-transitory computer readable medium of claim 73, wherein the stored instructions for determining whether to wait for the second RBO before transmitting on the first link comprise: The stored instructions are for determining, in response to determining that the second RBO is greater than a threshold, to transmit the first PPDU without waiting.

82. The non-transitory computer readable medium of claim 73, wherein the stored instructions for determining whether to wait for the second RBO before transmitting on the first link comprise: The stored instructions are for transmitting the first PPDU without waiting in response to determining that the second channel is blocked by a network allocation vector, NAV.

83. The non-transitory computer-readable medium of claim 73, wherein the stored instructions for determining whether to wait for the second RBO before transmitting on the first link comprise stored instructions for: determining to wait for the second RBO before transmitting on the first link; and A determination is made to transmit on the first link without waiting in response to determining that the second link is blocked.

84. The non-transitory computer readable medium of claim 83, wherein the stored instructions for determining that the second link is blocked comprise: Stored instructions for determining that a wait time has expired.

85. The non-transitory computer readable medium of claim 73, wherein the first RBO and the second RBO are initialized with the same value.

86. The non-transitory computer readable medium of claim 73, wherein the stored instructions include instructions for: Determining that the remaining countdown of the second RBO is less than a threshold; and The remaining countdown of the second RBO is set to zero when the second channel is idle.

87. The non-transitory computer readable medium of claim 86, wherein the stored instructions include instructions for: selecting a new RBO for the second channel of the second link; and The new RBO is increased based on the residual value of the second RBO.

88. The non-transitory computer readable medium of claim 87, wherein the stored instructions for increasing the new RBO based on the residual value of the second RBO comprise: Stored instructions for increasing the new RBO by the residual value multiplied by a configurable weighting factor.

89. The non-transitory computer readable medium of claim 73, wherein the stored instructions include instructions for: adding an offset to the first RBO and the second RBO based on a configurable weighting factor, wherein the stored instructions for transmitting at least the first PPDU on the first link during the TXOP comprise: The stored instructions are for transmitting the first PPDU on the first link and transmitting the second PPDU on the second link in response to determining that the first RBO or the second RBO has been counted down to zero, wherein the start time and the end time of the first PPDU and the second PPDU are aligned.

90. The non-transitory computer readable medium of claim 73, wherein the stored instructions include instructions for: determining to wait for the second RBO before transmitting on the first link; resetting the first RBO in response to another device using the first channel; and Wait for the first RBO and the second RBO to count down to zero.

91. The non-transitory computer readable medium of claim 76, wherein the stored instructions include: Instructions for setting a value of the first RBO based on the remaining countdown of the second RBO.

92. A non-transitory computer readable medium comprising stored instructions for wireless communications by a wireless access point, the stored instructions executable by a processor to: announcing a first enhanced distributed channel access EDCA set, wherein the first EDCA set includes first EDCA parameters for a first link; announcing a second EDCA set, the second EDCA set comprising second EDCA parameters for a second link; receiving a first physical protocol data unit PPDU from a station on said first link during a transmission opportunity TXOP; as well as A second PPDU is received from the station on the second link during the TXOP, wherein start times and end times of the first PPDU and the second PPDU are aligned.

93. The non-transitory computer-readable medium of claim 92, wherein the stored instructions are configured to: receive a medium reservation message on the first link reserving the TXOP for the station.

94. The non-transitory computer-readable medium of claim 93, wherein the medium reservation message is one of a Clear-To-Self (CTS2Self) message or a modified Request-To-Send (RTS) message.

95. The non-transitory computer-readable medium of claim 93, wherein the stored instructions are configured to refrain from transmitting a downlink PPDU on the second link during the TXOP in response to the medium reservation message.

96. The non-transitory computer readable medium of claim 92, wherein the second EDCA set comprises: First-stage EDCA parameters to be used when the station has not yet mastered another channel, and second-stage EDCA parameters to be used when the station has mastered another channel, wherein a random backoff RBO range of the second-stage EDCA parameters includes a value smaller than the RBO range of the first-stage EDCA parameters.

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