Method and apparatus for r-twt operation of latency sensitive traffic in a wlan

Abstract

This application is a divisional application of CN202180095207.X. Embodiments of the invention provide methods and devices for restricted target wake time (R-TWT) operation of latency sensitive traffic in WLAN. The method performed by an access point (AP) in an AP multi-link device (MLD) includes: sending a first response to a first station (STA) in a non-AP MLD, the first STA mapping at least one traffic identifier (TID) for latency sensitive traffic to at least one link established between the AP MLD and the non-AP MLD, wherein the AP MLD includes a plurality of APs and the non-AP MLD includes a plurality of non-AP STAs; and sending an R-TWT response to the first STA to establish an R-TWT protocol on any one or more of the at least one link to which at least one TID for latency sensitive traffic has been mapped.

Description

[0001] This application is a divisional application of the patent application No. CN202180095207.X titled "Method and apparatus for restricted target wake time operation for latency sensitive traffic in wireless local area network" filed on April 23, 2021. TECHNICAL FIELD

[0002] The present disclosure relates to target wake time (TWT) mechanism in wireless communication, and more particularly to a method and apparatus for restricted TWT (R-TWT) operation for latency sensitive traffic in wireless local area network (WLAN). BACKGROUND

[0003] The TWT mechanism was originally designed to manage activities in a basic service set (BSS) by scheduling stations (STAs) to reduce the wake-up time of the STAs required for power management. The Institute of Electrical and Electronics Engineers (IEEE) 802.11be introduces R-TWT operation, which provides more predictable latency with higher reliability for latency sensitive traffic based on the TWT mechanism. Generally, the R-TWT mechanism is used for protected transmission of latency sensitive traffic. Each latency sensitive traffic has a corresponding traffic identifier (TID).

[0004] In addition, the 802.11be also defines a directional based TID-to-link mapping mechanism across multiple links established between an access point (AP) multi-link device (MLD) including multiple APs and a non-AP MLD including multiple non-AP STAs. After successfully establishing multiple links between the AP MLD and the non-AP MLD, the TID-to-link mapping can be updated through negotiation between the AP MLD and the non-AP MLD if necessary.

[0005] However, the existing 802.11be has not defined a mechanism for R-TWT operation to cooperate with TID-to-link mapping. This can lead to inconsistency between scenarios formed by R-TWT operation and TID-to-link mapping.

[0006] Therefore, it is desirable to provide an effective mechanism for R-TWT operation for latency sensitive traffic to cooperate with TID-to-link mapping in WLAN, especially in IEEE 802.11be EHT WLAN. SUMMARY

[0007] Embodiments of the present disclosure provide a method and apparatus for R-TWT operation for latency sensitive traffic in WLAN. With the method and apparatus proposed in various embodiments of the present disclosure, R-TWT operation can effectively cooperate with TID-to-link mapping to avoid any possible inconsistent scenarios.

[0008] According to a first aspect of the present application, various embodiments of the present application provide a first method for R-TWT operation for latency sensitive traffic in WLAN performed at an AP side. The method can comprise: sending, by a first AP in an AP MLD, a first response to a first STA in a non-AP MLD to map at least one TID of latency sensitive traffic to at least one link established between the AP MLD and the non-AP MLD, wherein the AP MLD comprises a plurality of APs and the non-AP MLD comprises a plurality of non-AP STAs; and sending, by the first AP, an R-TWT response to the first STA to establish an R-TWT protocol on any one or more of the at least one link to which the at least one TID of latency sensitive traffic has been mapped.

[0009] According to a second aspect of the present application, various embodiments of the present application provide a second method for R-TWT operation for latency sensitive traffic in WLAN performed at a STA. The method can comprise: receiving, by a first STA in a non-AP MLD, a first response from a first AP in an AP MLD to map at least one TID of latency sensitive traffic to at least one link established between the AP MLD and the non-AP MLD, wherein the AP MLD comprises a plurality of APs and the non-AP MLD comprises a plurality of non-AP STAs; and receiving, by the first STA, an R-TWT response to establish an R-TWT protocol on any one or more of the at least one link to which the at least one TID of latency sensitive traffic has been mapped.

[0010] According to a third aspect of the present application, various embodiments of the present application provide an AP for R-TWT operation for latency sensitive traffic in WLAN. The AP can comprise: a TID-to-link mapping unit configured to send, to a first STA in a non-AP MLD, a first response to map at least one TID of latency sensitive traffic to at least one link established between an AP MLD and the non-AP MLD, wherein the AP MLD comprises a plurality of APs including the AP, and the non-AP MLD comprises a plurality of non-AP STAs including the first STA; and an R-TWT establishment unit configured to send, to the first STA, an R-TWT response to establish an R-TWT protocol on any one or more of the at least one link to which the at least one TID of latency sensitive traffic has been mapped.

[0011] According to a fourth aspect of the present application, various embodiments of the present application provide a STA for R-TWT operation of latency sensitive traffic in a WLAN. The STA can comprise: a TID-to-link mapping request unit configured to receive a first response from a first AP in an AP MLD to map at least one TID of latency sensitive traffic to at least one link established between the AP MLD and a non-AP MLD, wherein the AP MLD comprises a plurality of APs including the first AP, and the non-AP MLD comprises a plurality of non-AP STAs including the STA; and an R-TWT request unit configured to receive an R-TWT response from the first AP to establish an R-TWT protocol on any one or more of the at least one link to which the at least one TID of latency sensitive traffic has been mapped.

[0012] According to a fifth aspect of the present application, various embodiments of the present application provide an AP for R-TWT operation of latency sensitive traffic in a WLAN. The AP can comprise: a memory configured to store instructions for executing a first method for R-TWT operation of latency sensitive traffic in a WLAN; and a processor communicatively coupled to the memory, the processor configured to execute the instructions to perform the first method for R-TWT operation of latency sensitive traffic in a WLAN as described in various embodiments of the present application.

[0013] According to a sixth aspect of the present application, various embodiments of the present application provide a STA for R-TWT operation of latency sensitive traffic in a WLAN. The STA can comprise: a memory configured to store instructions for executing a second method for R-TWT operation of latency sensitive traffic in a WLAN; and a processor communicatively coupled to the memory, the processor configured to execute the instructions to perform the second method for R-TWT operation of latency sensitive traffic in a WLAN as described in various embodiments of the present application.

[0014] According to a seventh aspect of the present application, various embodiments of the present application provide a computer program product. The computer program product comprises instructions for causing a computer to perform the first method or the second method for R-TWT operation of latency sensitive traffic in a WLAN according to any of the embodiments of the present application when the instructions are executed on the computer.

[0015] According to an eighth aspect of the present application, various embodiments of the present application provide a computer program comprising instructions for causing a computer to perform the method for R-TWT operation of latency sensitive traffic in a WLAN according to any of the embodiments of the present application when the instructions are executed on the computer.

[0016] According to a ninth aspect of the present application, various embodiments of the present application provide a chip configured to perform the method for R-TWT operation for latency sensitive traffic in WLAN according to any of the embodiments of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0017] The present application will be described in detail with reference to the attached drawings, in which:

[0018] Figure 1 is a flow chart illustrating a first method for R-TWT operation for latency sensitive traffic in WLAN performed by a first AP according to various embodiments of the present application.

[0019] Figure 2 is a flow chart illustrating a second method for R-TWT operation for latency sensitive traffic in WLAN performed by a first non-AP STA according to various embodiments of the present application.

[0020] Figure 3A is a schematic diagram illustrating a method for R-TWT operation for latency sensitive traffic in WLAN according to a first embodiment of the present application.

[0021] Figure 3B is a block diagram illustrating a format of an R-TWT element according to some embodiments of the present application.

[0022] Figure 4 is a schematic diagram illustrating a method for R-TWT operation for latency sensitive traffic in WLAN according to a second embodiment of the present application.

[0023] Figure 5 is a schematic diagram illustrating a method for R-TWT operation for latency sensitive traffic in WLAN according to a third embodiment of the present application.

[0024] Figure 6 is a schematic diagram illustrating a method for R-TWT operation for latency sensitive traffic in WLAN according to a fourth embodiment of the present application.

[0025] Figure 7A is a block diagram illustrating a first format of a broadcast R-TWT parameter set field of an R-TWT element with TID-to-link mapping information according to some embodiments of the present application.

[0026] Figure 7B is a block diagram illustrating a second format of a broadcast R-TWT parameter set field of an R-TWT element with TID-to-link mapping information according to some embodiments of the present application.

[0027] Figure 7Cis a block diagram illustrating a third format of a broadcast R-TWT Parameter Set field of an R-TWT element with TID-to-link mapping information according to some embodiments of the application.

[0028] Figure 8A is a diagram illustrating R-TWT operation with a quiet element after R-TWT protocol has been established on multiple links according to one embodiment of the application.

[0029] Figure 8B is a diagram illustrating R-TWT operation with a TID-to-link mapping element indicating a suspended R-TWT operation mode after R-TWT protocol has been established on multiple links according to one embodiment of the application.

[0030] Figure 8C is a diagram illustrating R-TWT operation with a TID-to-link mapping element indicating a terminated R-TWT operation mode after R-TWT protocol has been established on multiple links according to one embodiment of the application.

[0031] Figure 9 is a block diagram illustrating a format of a TID-to-link mapping element of R-TWT information with a TIDx field according to some embodiments of the application.

[0032] Figure 10 is a diagram illustrating an AP according to some embodiments of the application.

[0033] Figure 11 is a diagram illustrating a STA according to some embodiments of the application. DETAILED DESCRIPTION

[0034] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the various illustrative embodiments of the present application. It will be apparent, however, to one skilled in the art that embodiments of the present application can be practiced without some or all of these specific details. It should be understood that the phraseology and terminology used herein is for the purpose of description and not of limitation.

[0035] Embodiments described in the context of a method or an apparatus are similarly applicable to the other and vice versa. Similarly, embodiments described in the context of a method are similarly applicable to an apparatus and vice versa.

[0036] Features described in the context of one embodiment can correspondingly be applied to the same or similar features in other embodiments. Features described in the context of one embodiment can correspondingly be applied to other embodiments, even if not explicitly described in these other embodiments. Furthermore, additions and / or combinations and / or alternatives of features described in the context of one embodiment can correspondingly be applied to the same or similar features in other embodiments.

[0037] As used herein, the articles “a,” “an,” and “the” include reference to one or more features or elements. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. As used herein, the terms “first,” “second,” and “third,” etc. are used only as labels, and do not imply a numerical requirement for their objects. As used herein, the term “configured to” can be interchangeable with “operated to” or “adapted to.”

[0038] Various embodiments of the present invention provide mechanisms for coordinating R-TWT protocol establishment procedures and R-TWT operation with TID-to-link mapping in WLANs. R-TWT operation is provided to allow an AP to use enhanced medium access protection and resource reservation mechanisms to provide more predictable latency and reduce worst-case latency and / or jitter, making the AP more reliable for latency-sensitive traffic. TID-to-link mapping is a directional-based TID-to-link mapping mechanism across multiple links established between an AP MLD comprising multiple APs and a non-AP MLD comprising multiple non-AP STAs. Each TID is used by a higher layer entity to differentiate media access control (MAC) service data units (MSDUs) to a MAC entity that supports quality of service (QoS) within MAC data traffic.

[0039] Figure 1 is a flowchart illustrating a first method 100 performed by a first AP for R-TWT operation for latency-sensitive traffic in a WLAN, according to various embodiments of the present invention. The first AP is an AP in an AP MLD comprising multiple APs, and a link can be established between the first AP and a first non-AP STA in a non-AP MLD comprising multiple non-AP STAs.

[0040] At block 101, a first request from a first STA is received by the first AP.

[0041] At block 102, a first response is sent by the first AP to the first STA to map at least one TID of latency-sensitive traffic to at least one link established between an AP MLD and a non-AP MLD, wherein the AP MLD comprises multiple APs and the non-AP MLD comprises multiple non-AP STAs.

[0042] In embodiments of the present application, the TIDs of latency sensitive traffic are also referred to as LL TIDs.

[0043] At block 103, an R-TWT request is received by the first AP from the first STA.

[0044] At block 104, an R-TWT response is sent by the first AP to the first STA to establish an R-TWT protocol on any one or more of the at least one link to which the at least one LL TID has been mapped.

[0045] While in the first method 100, the first AP sends the first response upon receiving the first request from the first STA, it should be noted that in some embodiments, the first AP can send an unsolicited first response to map the at least one TID of latency sensitive traffic to the at least one link established between the AP MLD and the non-AP MLD without receiving the first request. Further, in the first method 100, the R-TWT protocol is established through two steps in blocks 103 and 104. However, it should be noted that in other embodiments, the R-TWT protocol regarding any one or more of the at least one link to which the at least one LL TID has been mapped can be established through an unsolicited R-TWT response from the first AP to the first STA. That is, the first AP can not receive the R-TWT request from the first STA, but only send the unsolicited R-TWT response to the first STA to establish the R-TWT protocol on any one or more of the at least one link to which the at least one LL TID has been mapped.

[0046] Figure 2 is a flowchart illustrating a second method 200 performed by a first non-AP STA for R-TWT operation for latency sensitive traffic in a WLAN according to various embodiments of the present application.

[0047] At block 201, a first request is sent by the first STA to the first AP.

[0048] At block 202, a first response is received by the first STA from the first AP to map at least one LL TID to at least one link established between an AP MLD and a non-AP MLD, wherein the AP MLD comprises a plurality of APs and the non-AP MLD comprises a plurality of non-AP STAs.

[0049] At block 203, an R-TWT request is sent by the first STA to the first AP.

[0050] At block 204, the R-TWT response from the first AP is received by the first STA to establish the R-TWT protocol on any one or more of the at least one link to which the at least one LL TID has been mapped.

[0051] Although in the second method 200, the first STA sends the first request to the first AP before receiving the first response from the first AP, it should be noted that in some embodiments, the first STA can not send the first request and only receive the unsolicited first response from the first AP to map the at least one TID of the latency sensitive traffic to the at least one link established between the AP MLD and the non-AP MLD. Further, in the second method 200, the R-TWT protocol is established through two steps in blocks 103 and 104. However, it should be noted that in other embodiments, the R-TWT protocol regarding any one or more of the at least one link to which the at least one LL TID has been mapped can be established through an unsolicited R-TWT response from the first AP to the first STA. That is, the first STA can not send the R-TWT request and only receive the unsolicited R-TWT response from the first AP to establish the R-TWT protocol on any one or more of the at least one link to which the at least one LL TID has been mapped.

[0052] Multi-link setup procedure with default TID-to-link mapping

[0053] In some embodiments, the TID-to-link mapping procedure can be a default procedure conducted during or after a multi-link establishment procedure between the AP MLD and the non-AP MLD. In these embodiments, the first request received by the first AP can be a first multi-link association request from the first STA. The first response sent by the first AP can be a first multi-link association response sent to the first STA to establish multiple links between an AP in the AP MLD and a STA in the non-AP MLD and to default map all TIDs to all of the multiple links established between the AP MLD and the non-AP MLD, where the all TIDs include the at least one LL TID. In these embodiments, the R-TWT protocol can be established for any one or more of the links established between the AP MLD and the non-AP MLD.

[0054] Multi-link setup procedure with TID-to-link mapping negotiation

[0055] In some embodiments, the TID-to-link mapping can be established during a multi-link setup procedure through TID-to-link mapping negotiation, i.e., the negotiation can be included in the multi-link setup procedure. In these embodiments, the first request received by the first AP can be a second multi-link association request from the first STA. The first response sent by the first AP can be a second multi-link association response sent to the first STA to establish multiple links between the APs in the AP-MLD and the STAs in the non-AP MLD and map at least one TID of latency sensitive traffic to a subset of the links established between the AP-MLD and the non-AP MLD through negotiation between the first STA and the first AP.

[0056] In these embodiments, the at least one LL TID can be mapped to a subset of the links between the AP-MLD and the non-AP MLD. Each TID can be mapped to the same set of links or different sets of links. In one example, the non-AP MLD can indicate during the multi-link setup procedure (e.g., in the second multi-link association request sent from the first STA to the first AP) that the same set of links or different sets of links can be used for each TID. For example, the first STA can indicate in the second multi-link association request that the same set of links is used for all TIDs, or all TIDs are mapped to all the links established between the AP-MLD and the non-AP MLD.

[0057] TID-to-link mapping negotiation

[0058] In some embodiments, the TID-to-link mapping can be updated after the multi-link setup procedure through negotiation between the AP-MLD and the non-AP MLD, e.g., through negotiation between the first AP and the first STA. The negotiation can be initiated by the AP-MLD or the non-AP MLD according to uplink and downlink load, link status, and / or performance. The link status can include power saving status. In one embodiment, the first AP side negotiation can include receiving by the first AP a TID-to-link mapping request from the first STA, sending by the first AP a TID-to-link mapping response to the first STA to map at least one LL TID to a link between the AP-MLD and the non-AP MLD to which the at least one LL TID has not been mapped yet. Correspondingly, the first STA side negotiation can include sending by the first STA a TID-to-link mapping request to the first AP, receiving by the first STA a TID-to-link mapping response from the first AP to map at least one TID of latency sensitive traffic to a link between the AP-MLD and the non-AP MLD to which the at least one LL TID has not been mapped yet.

[0059] It should be noted that in some embodiments of the present application, TID-to-link mapping negotiation for all links established between the AP MLD and the non-AP MLD can be performed through this separate TID-to-link mapping negotiation procedure, instead of being performed together with the multi-link setup procedure or as a default procedure without negotiation.

[0060] In various embodiments, the R-TWT protocol setup procedure (i.e., the procedure of setting up the R-TWT protocol on any one or more of the at least one link to which the at least one LL TID has been mapped) is conducted through a negotiation between the AP MLD and the non-AP MLD (e.g., a negotiation between the first AP and the first STA). In the negotiation procedure, an R-TWT request is received by the first AP from the first STA; a first R-TWT response is sent by the first AP to the first STA to set up the R-TWT protocol on any one or more of the at least one link to which the at least one LL TID has been mapped. In one example, if there are two links between the AP MLD and the non-AP MLD, link 1 is established between the first AP and the first STA, and link 2 is established between the second AP and the second STA, then a negotiation between the first AP and the first STA can be conducted to set up the R-TWT protocol on link 1, or link 2, or both. The R-TWT protocols set up on link 1 and link 2 can have the same or different start time, end time, and other parameters.

[0061] In some embodiments, the R-TWT request from the first STA and / or the R-TWT response from the first AP can include an R-TWT element including a first subfield and a second subfield in a control field, where the first subfield is set to indicate whether the information included in the R-TWT element is used for negotiation of R-TWT parameters, and the second subfield is set to indicate whether the information included in the R-TWT element applies to all links to which at least one TID of latency-sensitive traffic has been mapped.

[0062] R-TWT setup procedure with integrated TID-to-link mapping negotiation

[0063] In some embodiments, the TID-to-link mapping procedure and the R-TWT establishment procedure can be conducted together with a negotiation between the AP MLD and the non-AP MLD (e.g., a negotiation between the first AP and the first STA). The first-AP-side negotiation can include receiving, by the first AP, an integrated R-TWT request from the first STA, and transmitting, by the first AP to the first STA, an integrated R-TWT response to map at least one TID of latency-sensitive traffic to at least one link between the AP-MLD and the non-AP MLD to which the at least one LL TID has not been mapped yet, and establish an R-TWT protocol on any one or more of the at least one link to which the at least one LL TID has been mapped.

[0064] Accordingly, the first-STA-side negotiation can include transmitting, by the first STA to the first AP, an integrated R-TWT request, and receiving, by the first STA from the first AP, an integrated R-TWT response to map at least one TID of latency-sensitive traffic to at least one link between the AP-MLD and the non-AP MLD to which the at least one LL TID has not been mapped yet, and establish an R-TWT protocol on any one or more of the at least one link to which the at least one LL TID has been mapped.

[0065] It should be noted that, in some embodiments, all TID-to-link mapping negotiation between the AP MLD and the non-AP MLD can be conducted through the integrated procedure, or only the negotiation procedure can be conducted to establish TID-to-link mapping for a specific link after TID-to-link mapping for multiple links between the AP MLD and the non-AP MLD has been established during the multi-link establishment procedure.

[0066] In some embodiments, the integrated R-TWT request can include a first R-TWT element set to indicate both the at least one link on which the R-TWT protocol is to be established and the at least one link to which the at least one LL TID is to be mapped. In some embodiments, the integrated R-TWT response can include a second R-TWT element set to indicate both the one or more links on which the R-TWT protocol has been established and the at least one link to which the at least one LL TID has been mapped. Preferably, the R-TWT element can be included in both the second R-TWT request and the second R-TWT response.

[0067] In some embodiments, the integrated R-TWT request and / or the integrated R-TWT response can be set to include at least one first R-TWT element indicating at least one link on which to establish an R-TWT protocol, e.g., at least one link on which to establish or has established an R protocol, and at least one TID-to-link mapping element indicating at least one link to which at least one TID of latency sensitive traffic is mapped, e.g., at least one LL TID is to be mapped or has been mapped to.

[0068] Alternatively, in some embodiments, the integrated R-TWT request and / or the integrated R-TWT response can be set to include at least one second R-TWT element indicating one or more links on which to establish an R-TWT protocol and at least one link to which at least one TID of latency sensitive traffic is mapped. In a first example, the second R-TWT element can include a broadcast R-TWT parameter set field set to include a first subfield (e.g., a link ID bitmap field) indicating at least one link to which an R-TWT is applied, a second subfield (e.g., a link mapping of TIDs of downlink) indicating at least one link on which to send frames belonging to TIDs of latency sensitive traffic of downlink, and a third subfield (e.g., a link mapping of TIDs of uplink) indicating at least one link on which to send frames belonging to TIDs of latency sensitive traffic of uplink. In a second example, the second R-TWT element can include a broadcast R-TWT parameter set field set to include a R-TWT traffic information field, a link ID bitmap field, and a subfield of request type field for R-TWT, e.g., an R-TWT subfield set to indicate whether a TWT schedule specified by a corresponding broadcast TWT parameter set field is an R-TWT schedule. In a third example, the second R-TWT element is the same as the second example, except in the third example, the broadcast R-TWT parameter set field includes two link ID bitmap fields, e.g., a link ID bitmap field of UL TIDs and a link ID bitmap field of DL TIDs.

[0069] R-TWT operation after R-TWT setup procedure

[0070] In some embodiments, the method can further comprise: if no TID of latency sensitive traffic is mapped to the first link established between the first AP and the first STA due to the TID-to-link mapping update / change, the R-TWT protocol established on the first link is torn down by the first AP and the first STA. For example, the R-TWT protocol can be torn down by a termination procedure, which comprises: the first AP sends a TID-to-link mapping element with an R-TWT termination mode indication on the first link to terminate the R-TWT protocol on the first link. Accordingly, the first STA tears down the R-TWT protocol on the first link upon receiving the TID-to-link mapping element with the R-TWT termination mode indication sent on the first link. The termination procedure can be performed when the AP MLD and the non-AP MLD do not support or enter the suspended R-TWT operation mode.

[0071] In some embodiments, when the AP MLD and the non-AP MLD support the suspended R-TWT operation mode, the first method 100 at the first AP can further comprise: if no TID of latency sensitive traffic is mapped to the first link established between the first AP and the first STA, the first AP can send an R-TWT SP silent element or a TID-to-link mapping element with a suspended R-TWT mode indication on the first link to make the first link enter the suspended R-TWT operation mode, or the first AP can send a TID-to-link mapping element with an R-TWT termination mode indication on the first link to terminate the R-TWT protocol on the first link.

[0072] Accordingly, the second method 200 at the first STA can further comprise: when no TID of latency sensitive traffic is mapped to the first link established between the first AP and the first STA, the first STA receives the R-TWT SP silent element or the TID-to-link mapping element with the suspended R-TWT mode indication sent by the first AP on the first link, and the first STA makes the first link enter the suspended R-TWT operation mode; or, the first STA makes the R-TWT protocol on the first link enter the R-TWT termination mode upon receiving the TID-to-link mapping element with the R-TWT termination mode indication. Preferably, the first method 100 and the second method 200 can further comprise: when the first link enters the suspended R-TWT operation mode, if the duration of the suspended R-TWT operation mode exceeds a predetermined threshold, the R-TWT protocol on the first link can be torn down.

[0073] In some embodiments, the TID-to-link mapping element can include an R-TWT information field for the TID, which is set to indicate whether at least one TID of the delay-sensitive traffic is mapped to the plurality of links established between the AP MLD and the non-AP MLD, and a status of the R-TWT operation, wherein the R-TWT operation status is set to indicate a paused R-TWT operation mode, or an R-TWT terminated mode, or an R-TWT mode that is not present.

[0074] It should be noted that the R-TWT protocol establishment procedure in various embodiments of the present application can also include establishing membership for non-AP STAs in the non-AP MLD in a broadcast TWT after the R-TWT protocol has been established between the non-AP MLD and the AP MLD. Some embodiments of the present application will be described below to illustrate the method for R-TWT operation for delay-sensitive traffic in a WLAN according to various embodiments of the present application. It should be noted that these embodiments are provided only for illustrative purposes, and are not intended to limit the scope of the present application.

[0075] First embodiment (multi-link setup with default TID-to-link mapping)

[0076] Figure 3A is a schematic diagram showing a method 300 for R-TWT operation for delay-sensitive traffic in a WLAN according to a first embodiment of the present application. In this embodiment, the AP MLD includes three APs, i.e., AP1, AP2 and AP3, and the non-AP MLD includes three non-AP STAs, i.e., STA1, STA2 and STA3. As shown in FIG. 3, the method 300 includes the following steps:

[0077] Step 301, STA1 sends a first multi-link association request to AP1 to request the establishment of a plurality of links between the AP MLD and the non-AP MLD. In this embodiment, the plurality of links between the AP MLD and the non-AP MLD includes a link 1 between AP1 and STA1, a link 2 between AP2 and STA2, and a link 3 between AP3 and STA3.

[0078] Step 302, after receiving the first multi-link association request, AP1 sends a first multi-link association response to AP1 to establish the link 1, the link 2 and the link 3.

[0079] Step 303, all TIDs are mapped to all links established between the AP MLD and the non-AP MLD, i.e., the link 1, the link 2 and the link 3.

[0080] Steps 301 and 302 are performed to establish link 1 between AP1 and STA1, link 2 between AP2 and STA2, and link 3 between AP3 and STA3. This is the multi-link setup procedure in the present embodiment. Although the multi-link setup procedure is performed using AP1 and STA1 in the present embodiment, it is appreciated by those skilled in the art that the multi-link setup procedure can also be performed using AP2 and STA2, or AP3 and STA3 in other embodiments. In the present embodiment, the TID-to-link mapping is a default procedure performed after the multi-link setup procedure. In the default procedure, all TIDs including at least one TID of latency-sensitive traffic are mapped to all links established between the AP MLD and the non-AP MLD, i.e., link 1, link 2 and link 3 in the present embodiment.

[0081] Step 304, STA1 sends an R-TWT request to AP1 to request to establish the R-TWT protocol on all links established between the AP MLD and the non-AP MLD.

[0082] Step 305, AP1 sends an R-TWT response to STA1 to establish the R-TWT protocol on all links established between the AP MLD and the non-AP MLD after receiving the R-TWT request from STA1.

[0083] Step 306, the R-TWT protocol is established on all links established between the AP MLD and the non-AP MLD, i.e., link 1, link 2 and link 3 in the present embodiment.

[0084] It is noted that although the R-TWT protocol is established on all links established between the AP MLD and the non-AP MLD in the present embodiment, in other embodiments, the R-TWT protocol can be established on any one or more links established between the AP MLD and the non-AP MLD.

[0085] In the first embodiment, the R-TWT request and / or the R-TWT response can include one or more R-TWT elements set to indicate whether to establish the R-TWT protocol on all links between the AP MLD and the non-AP MLD.

[0086] Figure 3B is a block diagram showing the format of an R-TWT element according to some embodiments of the present application. As Figure 3BAs shown, the control field of the R-TWT element includes a restricted-TWT (R-TWT) indicator subfield and an applied link indicator subfield. The R-TWT indicator subfield is set to indicate whether the information included in the element is for negotiation of R-TWT parameters. For example, the R-TWT indicator subfield can be set to 1 to indicate that the information is for R-TWT, or set to 0 to indicate that the information is not for R-TWT. In this embodiment, the applied link indicator subfield can be set to indicate whether the information included in the element is to be applied to all links established between the AP-MLD and the non-AP MLD. Alternatively, the applied link indicator subfield can be set to indicate whether the information included in the element is to be applied to all links to which at least one TID of latency-sensitive traffic has been mapped. For example, the applied link indicator subfield can be set to 1 to indicate “yes”, i.e., the information is to be applied to all links to which at least one TID of latency-sensitive traffic has been mapped, or set to 0 to indicate “no”, i.e., the information is not to be applied to all links to which at least one TID of latency-sensitive traffic has been mapped. It should be noted that in other embodiments, the R-TWT indicator subfield and the applied link subfield in the control field of the R-TWT element can have different names.

[0087] Second embodiment (multi-link setup with TID-to-link mapping negotiation)

[0088] Figure 4 is a schematic diagram showing a method 400 for R-TWT operation for latency-sensitive traffic in a WLAN according to a second embodiment of the present application. In this embodiment, the AP MLD includes three APs, i.e., AP1, AP2 and AP3, and the non-AP MLD includes three non-AP STAs, i.e., STA1, STA2 and STA3. As shown in FIG. 4A, the method 400 includes the following steps: Figure 4

[0089] Step 401, STA1 sends a second multi-link association request to AP1 to request establishment of multiple links between the AP MLD and the non-AP MLD. In this embodiment, the multiple links include a link 1 between AP1 and STA1, a link 2 between AP2 and STA2, and a link 3 between AP3 and STA3.

[0090] Step 402, after receiving the multi-link association request, AP1 sends a second multi-link association response to AP1 to establish the link 1, the link 2 and the link 3.

[0091] Step 403, a TID of latency-sensitive traffic is mapped to the link 1 and the link 2. In this embodiment, there is more than one TID of latency-sensitive traffic mapped to the link 1 and the link 2.

[0092] ​At step 404, STA1 sends an R-TWT request to AP1 to request to establish an R-TWT protocol on Link 1 and Link 2.

[0093] At step 405, AP1 sends an R-TWT response to STA1 to establish an R-TWT protocol on Link 1 and Link 2 after receiving the R-TWT request from STA1.

[0094] At step 406, an R-TWT protocol is established on Link 1 and Link 2.

[0095] In the second embodiment, steps 401 and 402 are performed to establish multiple links between the AP MLD and the non-AP MLD. The multi-link establishment procedure is the same as in the first embodiment. In this embodiment, the mapping of TIDs to links is a negotiation procedure that is performed together with the multi-link establishment procedure. After the negotiation procedure, at least one TID of the latency-sensitive traffic is mapped to only Link 1 and Link 2 among all the links established between the AP MLD and the non-AP MLD.

[0096] In the second embodiment, an R-TWT protocol is established on all the links (i.e., Link 1 and Link 2) to which at least one TID of the latency-sensitive traffic is mapped. It should be noted that in other embodiments, the R-TWT protocol can be mapped to only Link 1 or Link 2.

[0097] In the second embodiment, the R-TWT request and / or the R-TWT response can include one or more R-TWT elements that are set to indicate whether an R-TWT protocol is established on all the links to which at least one TID of the latency-sensitive traffic is mapped. The format of the R-TWT element can be as shown in Figure 3B The control field of the R-TWT element includes an R-TWT indicator subfield and an apply link subfield. The R-TWT indicator subfield is set to indicate whether the information included in the element is used for negotiation of R-TWT parameters (e.g., the parameters shown in the R-TWT parameter set field of the R-TWT element). For example, the R-TWT indicator subfield can be set to 1 to indicate that the information is used for R-TWT, or set to 0 to indicate that the information is not used for R-TWT. The apply link indicator subfield can be set to indicate whether the information included in the element is to be applied to all the links to which at least one TID of the latency-sensitive traffic is mapped. For example, the apply link indicator subfield can be set to 1 to indicate that the information is to be applied to all the links to which at least one TID of the latency-sensitive traffic is mapped, or set to 0 to indicate that the information is not to be applied to all the links to which at least one TID of the latency-sensitive traffic is mapped.

[0098] Third embodiment (separate TID-to-link mapping)

[0099] Figure 5 is a schematic diagram illustrating a method 500 for R-TWT operation for latency sensitive traffic in WLAN according to a third embodiment of the present application. In this embodiment, the AP MLD comprises three APs, i.e., AP1, AP2 and AP3, and the non-AP MLD comprises three non-AP STAs, i.e., STA1, STA2 and STA3. As shown, the method 500 comprises the following steps: Figure 5

[0100] Steps 501 to 503 are the same as steps 401 to 403 respectively. They are not repeated here.

[0101] Step 504, STA1 sends a TID-to-link mapping request to STA1 to request mapping at least one TID of latency sensitive traffic to link 3.

[0102] Step 505, AP1 sends a TID-to-link mapping response to STA1 to map at least one TID of latency sensitive traffic to link 3 after receiving the TID-to-link mapping request.

[0103] Step 506, the TID of latency sensitive traffic is mapped to link 3. It should be noted that in this embodiment, multiple TIDs of latency sensitive traffic are mapped to link 3.

[0104] Step 507, STA1 sends an R-TWT request to AP1 to request establishing R-TWT protocol on all links to which at least one TID of latency sensitive traffic has been mapped. In this embodiment, the links include link 1, link 2 and link 3.

[0105] Step 508, AP1 sends an R-TWT response to STA1 to establish R-TWT protocol on link 1, link 2 and link 3 after receiving the first R-TWT request from STA1.

[0106] Step 509, R-TWT protocol is established on link 1, link 2, link 3.

[0107] The same as the second embodiment, in the third embodiment, after the TID-to-link mapping negotiation, at least one LL TID is only mapped to link 1 and link 2, and no LL TID is mapped to link 3. However, the STA1 initiates a TID-to-link mapping update negotiation to establish the mapping of at least one LL TID to link 3. After mapping at least one LL TID to link 3, the R-TWT protocol establishment process is performed to establish R-TWT protocol on all links to which at least one LL TID has been mapped.

[0108] ​Similar to the second embodiment, in the third embodiment, the R-TWT request and / or the R-TWT response can include one or more R-TWT elements set to indicate whether to establish the R-TWT protocol on all links to which the at least one LL TID has been mapped. The format of the R-TWT element can be as shown in Figure 3B

[0109] Fourth embodiment (R-TWT setup with integrated TID-to-link mapping negotiation)

[0110] Figure 6 is a schematic diagram showing a method 600 for R-TWT operation for latency sensitive traffic in a WLAN according to a fourth embodiment of the present application. In this embodiment, the AP MLD includes three APs, i.e., AP1, AP2 and AP3, and the non-AP MLD includes three non-AP STAs, i.e., STA1, STA2 and STA3. As shown in Figure 5

[0111] Steps 601 to 603 are the same as steps 401 to 403 respectively. They are not repeated here. In this embodiment, link 1, link 2 and link 3 are established during the multi-link setup procedure, and through the TID-to-link mapping negotiation, the at least one LL TID is mapped to only link 1 and link 2. No LL TID is mapped to link 3.

[0112] Step 604, STA1 sends an integrated R-TWT request to AP1 to request mapping the at least one LL TID to link 3, and to request establishing the R-TWT protocol on link 1, link 2 and link 3.

[0113] Step 605, after receiving the integrated R-TWT request from STA1, AP1 sends an integrated R-TWT response to STA1 to map the TID of the latency sensitive traffic to link 3, and to establish the R-TWT protocol on link 1, link 2 and link 3.

[0114] Step 606, the R-TWT protocol is established on link 1, link 2 and link 3.

[0115] ​​Unlike the above embodiments, in this embodiment, the TID-to-link mapping negotiation for link 3 is integrated with the R-TWT setup procedure. To conduct the TID-to-link mapping negotiation together with the R-TWT setup procedure, the integrated R-TWT request and the integrated R-TWT response can be set to include one or more R-TWT elements and a TID-to-link mapping element. Alternatively, the integrated R-TWT request and the integrated R-TWT response can be set to include one or more R-TWT elements, where each R-TWT element is set to include one or more TID-to-link mapping subfields.

[0116] In one example, the integrated R-TWT request can be set to include an R-TWT element that is set to indicate not only the link on which the R-TWT protocol is to be established, but also the link to which the TID of the latency-sensitive traffic is to be mapped. Upon receiving the integrated R-TWT request, AP 1 decides whether to establish the requested TID-to-link mapping for link 3, as well as whether to establish the R-TWT protocol on the requested links (i.e., link 1, link 2, and link 3 in this embodiment), and sends an integrated R-TWT response to STA 1. The integrated R-TWT response can be set to include an R-TWT element that is set to indicate the link to which the TID of the latency-sensitive traffic has been mapped and on which the R-TWT protocol has been established, e.g., by accepting the value of TWT.

[0117] Figure 7A is a block diagram illustrating a first format of a broadcast R-TWT parameter set field of an R-TWT element with TID-to-link mapping information according to some embodiments of the application. As shown in Figure 7A the broadcast R-TWT parameter set field is set to include a link ID bitmap subfield, a TID-to-link mapping subfield for the downlink direction, and a TID-to-link mapping subfield for the uplink direction.

[0118] The link ID bitmap subfield is set to indicate at least one link to which the R-TWT element is applied. Each bit position of the link bitmap subfield corresponds to a link ID associated with a link. Each bit position can be set to indicate whether the R-TWT element is applied to the associated link. For example, bit position m of the link bitmap subfield corresponds to link ID m. Bit position m can be set to “1” to indicate that the R-TWT element is applied to the link associated with link ID m, or set to “0” to indicate that the R-TWT element is not applied to the link associated with link ID m. If the link ID bitmap subfield is not present in the broadcast R-TWT parameter field, the link to which the R-TWT element is applied is the link on which the R-TWT element is transmitted.

[0119] The link mapping subfield for a downlink TID (e.g., TID i) can be set to indicate at least one link over which frames belonging to the latency sensitive traffic of TID i in the downlink direction are transmitted. Each bit position of the link mapping subfield for a downlink TID i can correspond to a link ID associated with a link. For example, bit position m of the link mapping subfield for a downlink TID i corresponds to link ID m. Bit position m can be set to "1" to indicate that TID i is mapped to the link associated with link ID m in the downlink direction, or set to "0" to indicate that TID i is not mapped to the link associated with link ID m in the downlink direction.

[0120] The link mapping subfield for a downlink TID (e.g., TID i) can be set to indicate at least one link over which frames belonging to the latency sensitive traffic of TID i in the downlink direction are transmitted. Each bit position of the link mapping subfield for a downlink TID i can correspond to a link ID associated with a link. For example, bit position m of the link mapping subfield for a downlink TID i corresponds to link ID m. Bit position m can be set to "1" to indicate that TID i is mapped to the link associated with link ID m in the downlink direction, or set to "0" to indicate that TID i is not mapped to the link associated with link ID m in the downlink direction.

[0121] Figure 7B is a block diagram illustrating a second format of the broadcast R-TWT parameter set field of the R-TWT element with TID-to-link mapping information according to some embodiments of the application. As shown in Figure 7B the request type field of the broadcast R-TWT parameter set field includes an R-TWT subfield set to indicate whether the TWT schedule specified by the corresponding broadcast TWT parameter set field is an R-TWT schedule. For example, the R-TWT subfield can be set to 1 to indicate that the TWT schedule specified by the corresponding broadcast TWT parameter set field is an R-TWT schedule, and 0 otherwise. The broadcast R-TWT parameter set field further includes a link ID bitmap field and an R-TWT traffic information field.

[0122] In this example, the Link ID bitmap is a field of the Broadcast TWT Parameter Set field. Alternatively, in other embodiments of the invention, the Link ID bitmap can be a subfield of the R-TWT Traffic Information field. The Link ID bitmap field is set to indicate at least one link to which the R-TWT element is applied. A value of 1 in bit position m of the Link ID bitmap field can indicate that the link associated with Link ID m is a link to which the R-TWT element is applied. A value of 0 in bit position m of the Link ID bitmap field can indicate that the link associated with Link ID m is not a link to which the TWT element is applied. If the Link ID bitmap field is not present in the Broadcast TWT Parameter Set field, the link to which the R-TWT element is applied is the link on which the R-TWT element is transmitted.

[0123] The R-TWT DL / UL TID bitmap subfield in the R-TWT Traffic Information field is set to indicate which TID(s) is / are identified by the TWT scheduling AP or by the TWT scheduled STA as latency sensitive traffic stream in the downlink direction on the link indicated in the Link ID bitmap subfield. The Restricted TWT UL TID bitmap subfield is set to indicate which TID(s) is / are identified by the TWT scheduling AP or by the TWT scheduled STA as latency sensitive traffic stream in the uplink direction on the link indicated in the Link ID bitmap subfield. A value of 1 or 0 at bit position k in the bitmap can be set to indicate that TID k is classified as latency sensitive traffic stream and MSDUs of TID k are allowed / not allowed to be transmitted on the link indicated in the Link ID bitmap subfield in the one or more R-TWT SPs indicated by the TWT element.

[0124] Figure 7C is a block diagram illustrating a third format of the Broadcast R-TWT Parameter Set field of the R-TWT element with TID-to-link mapping information according to some embodiments of the invention. As Figure 7C shown, in the third format, the Request Type field of the Broadcast R-TWT Parameter Set field includes an R-TWT subfield, which is the same as the R-TWT subfield in the second example shown in Figure 7B The Broadcast R-TWT Parameter Set field also includes a Link ID bitmap field of UL TIDs, a Link ID bitmap field of DL TIDs, and an R-TWT Traffic Information field.

[0125] The Link ID bitmap of DL TIDs is in this third format as Figure 7CThe Link ID bitmap field of the Broadcast TWT Parameter Set field is set to indicate at least one link to which one or more DL TIDs are mapped. A value of 1 in bit position m of the Link ID bitmap field of the DL TIDs can indicate that the link associated with Link ID m is a link to which one or more DL TIDs are mapped. A value of 0 in bit position m of the Link ID bitmap field of the DL TIDs can indicate that the link associated with Link ID m is not a link to which one or more DL TIDs are mapped.

[0126] Similarly, the Link ID bitmap of the UL TIDs is a field of the Broadcast TWT Parameter Set field in the third format as shown in Figure 7C The Link ID bitmap field of the Broadcast TWT Parameter Set field is set to indicate at least one link to which one or more UL TIDs are mapped. A value of 1 in bit position m of the Link ID bitmap field of the UL TIDs can indicate that the link associated with Link ID m is a link to which one or more UL TIDs are mapped. A value of 0 in bit position m of the Link ID bitmap field of the UL TIDs can indicate that the link associated with Link ID m is not a link to which one or more UL TIDs are mapped.

[0127] The R-TWT DL TID bitmap subfield in the R-TWT Traffic Information field can be set to indicate which TID(s) are identified by the TWT scheduling AP or the TWT scheduled STA as latency sensitive traffic flows in the downlink on the links indicated in the Link ID bitmap field of the DL TIDs. A value of 1 or 0 at bit position k in the bitmap can indicate that TID k is classified as a latency sensitive traffic flow and MSDUs of TID k are allowed or not allowed to be transmitted in the one or more restricted TWT SPs specified by the TWT element on the links indicated in the Link ID bitmap field of the DL TIDs.

[0128] The R-TWT UL TID bitmap subfield in the R-TWT Traffic Information field can be set to indicate which TID(s) are identified by the TWT scheduling AP or the TWT scheduled STA as latency sensitive traffic flows in the uplink on the links indicated in the Link ID bitmap subfield of the UL TIDs. A value of 1 or 0 at bit position k in the bitmap can indicate that TID k is classified as a latency sensitive traffic flow and MSDUs of TID k are allowed or not allowed to be transmitted in the one or more restricted TWT SPs specified by the TWT element on the links indicated in the Link ID bitmap field of the UL TIDs.

[0129] Those skilled in the art should understand that in other embodiments of the present application, if AP1 does not accept the request for TID-to-link mapping, the requested TID-to-link mapping can not be established, and accordingly, the R-TWT protocol can only be established on one or more requested links according to the decision of AP1.

[0130] In some embodiments of the present application, after the R-TWT protocol is successfully established on at least one link between the AP MLD and the non-AP MLD, it can be found that no LL TID is mapped to one or more links on which the R-TWT protocol has been established due to TID-to-link mapping update / change. Figures 8A to 8C Three possible ways of R-TWT operation in these scenarios are shown according to some embodiments of the present application.

[0131] R-TWT SP silence element

[0132] Figure 8A is a schematic diagram showing R-TWT operation with the silent element after the R-TWT protocol is established on multiple links according to one embodiment of the present application. In this embodiment, the AP MLD and the non-AP MLD do not support the paused R-TWT operation mode. In this embodiment, AP1, AP2, AP3 in the AP MLD are EHT APs, and the non-AP STA in the non-AP MLD can be an EHT STA or a pre-EHT STA.

[0133] Referring to Figure 8A , the R-TWT protocol has been established on three links (i.e., link 1, link 2, and link 3) between the AP MLD and the non-AP MLD. When no LL TID is mapped to link 1 due to TID-to-link mapping update / change, AP1 sends / broadcasts an R-TWT SP silent element on link 1 to announce an R-TWT SP silent interval. During the R-TWT SP silent interval, the R-TWT SP will be ignored. As shown in Figure 8A , two R-TWT SP silent elements are sent on link 1. Similarly, in this embodiment, no LL TID is mapped to link 3 due to TID-to-link mapping update, three R-TWT SP silent elements are sent by AP3 on link 3. The R-TWT SP silent element can be included in a management (MGMT) frame sent from AP1 / AP3 to STA1 / STA3. STA1 and STA3 receive the R-TWT SP silent element and will ignore the R-TWT SP overlapping with the R-TWT SP silent interval. In addition, if the duration of the R-TWT silent interval on a link exceeds a predetermined threshold, the R-TWT protocol on that link can be torn down.

[0134] Paused R-TWT operation mode

[0135] Figure 8B is a diagram illustrating R-TWT operation with TID-to-link mapping element with suspend indication after R-TWT protocol has been established on multiple links according to one embodiment of the present application. In this embodiment, the AP MLD and non-AP MLD support suspend R-TWT operation mode. In this embodiment, AP1, AP2, AP3 in the AP MLD are EHT APs, while the non-AP STAs in the non-AP MLD can be EHT STAs or pre-EHT STAs.

[0136] Referring to Figure 8B , R-TWT protocol has been established on three links (i.e., Link 1, Link 2, and Link 3) between the AP MLD and the non-AP MLD. When there is no LL TID mapped to Link 1 due to TID-to-link mapping update / change, AP1 sends / broadcasts TID-to-link mapping element with suspend R-TWT mode indication on Link 1 to announce the updated TID mapped to Link 1. The TID-to-link mapping element with suspend R-TWT mode indication can be included in the MGMT frame transmitted from AP1 to STA1 on Link 1. In this embodiment, two TID-to-link mapping elements are transmitted on Link 1. Similarly, in this embodiment, there is also no LL TID mapped to Link 3 due to TID-to-link mapping update, three TID-to-link mapping elements are sent by AP3 on Link 3.

[0137] Once STA1 and STA3 receive the TID-to-link mapping element with suspend R-TWT mode indication on Link 1 and Link 3, respectively, the R-TWT SP will be ignored during the validity time interval of the updated TID-to-link mapping indicated in the TID-to-link mapping element. In addition, if the duration of the updated TID-to-link mapping indicated in the TID-to-link mapping element on a link exceeds a predetermined threshold, the R-TWT protocol on that link can be torn down.

[0138] Terminated R-TWT operation mode

[0139] Figure 8CThis is a schematic diagram illustrating R-TWT operation of a TID-to-link mapping element using an indicated termination R-TWT operation mode after R-TWT protocols have been established on multiple links, according to an embodiment of the present invention. In this embodiment, both AP MLDs and non-AP MLDs support a suspended R-TWT operation mode. In this embodiment, AP1, AP2, and AP3 in the AP MLD are EHT APs, while the non-AP STAs in the non-AP MLD can be EHT STAs or pre-EHT STAs.

[0140] Reference Figure 8C The R-TWT protocol has been established on three links (i.e., link 1, link 2, and link 3) between the AP MLD and the non-AP MLD. When no LL TID is mapped to all of links 1, 2, and 3 due to a TID-to-link mapping update / change, each AP in the AP MLD sends a TID-to-link mapping element with a terminating R-TWT mode indication on the corresponding link to announce the updated TID mapped to the corresponding link. The TID-to-link mapping element can be included in the MGMT frame transmitted from the AP to the STA on the corresponding link.

[0141] Once each STA in a non-AP MLD receives a TID-to-link mapping element on its corresponding link, the R-TWT SP will be ignored during the valid time interval of the updated TID-to-link mapping indicated in the TID-to-link mapping element. Furthermore, if the duration of the updated TID-to-link mapping indicated in the TID-to-link mapping element on the link exceeds a predetermined threshold, the R-TWT protocol on that link can be terminated.

[0142] Figure 9 This is a block diagram illustrating the format of a TID-to-link mapping element having an R-TWT information field with TID x according to some embodiments of the present invention. Figure 9 The format shown can be used in Figure 8B and Figure 8C In the embodiments described above. See also Figure 9 The TID-to-link mapping element is configured to include an R-TWT information field for TID x. The R-TWT information field for TID x is configured to indicate whether any LL TID is mapped to a link established between an AP MLD and a non-AP MLD, and whether R-TWT is permitted on these links. Two bits are allocated to each link to indicate the status of R-TWT operation on the link. For example, the two bits allocated to a link can be set to "11" to indicate that R-TWT operation is terminated on that link, or set to "10" to indicate that R-TWT operation is paused on that link, or set to "00" to indicate that an R-TWT protocol has not yet been established on that link.

[0143] In the above embodiments as shown in Figures 8A to 8C the R-TWT element, the R-TWT SP silent element, the TID-to-link mapping element with pause R-TWT mode indication, and the TID-to-link mapping element with terminate R-TWT mode indication can be broadcast elements on a link established between the AP MLD and the non-AP MLD. However, in other embodiments, these elements can not be broadcast elements.

[0144] Various embodiments of the present disclosure also provide an AP for R-TWT operation for latency sensitive traffic in a WLAN. Figure 10 is a schematic diagram illustrating an AP 1000 according to some embodiments of the present disclosure. Referring to Figure 10 , the AP 1000 can comprise a TID-to-link mapping unit 1010 and an R-TWT establishment unit 1020. The TID-to-link mapping unit 1010 can be configured to send a first response to a first STA in a non-AP MLD to map at least one TID of latency sensitive traffic to at least one link established between an AP MLD and the non-AP MLD, wherein the AP MLD comprises a plurality of APs including the AP, and the non-AP MLD comprises a plurality of non-AP STAs including the first STA. The R-TWT establishment unit 1020 can be configured to send an R-TWT response to the first STA to establish an R-TWT protocol on any one or more of the at least one link to which the at least one TID of latency sensitive traffic has been mapped.

[0145] In some embodiments, the TID-to-link mapping unit can be further configured to receive a first request from the first STA. That is, the first response from the first AP can be an unsolicited response or a solicited response.

[0146] In some embodiments, the TID-to-link mapping unit 1010 can comprise a first receiving unit configured to receive a first multi-link association request from the first STA, and a first transmitting unit 1 configured to send a first multi-link association response to the first STA to establish a plurality of links between an AP in an AP-MLD and a STA in a non-AP MLD, and to map all TIDs to all of the plurality of links established between the AP MLD and the non-AP MLD by default, wherein the all TIDs comprise the at least one TID of latency sensitive traffic.

[0147] Alternatively, in some embodiments, the TID-to-link mapping unit 1010 can comprise a second receiving unit configured to receive a second multi-link association request from the first STA, and a second transmitting unit configured to transmit a second multi-link association response to the first STA to establish a plurality of links between the AP in the AP-MLD and the STA in the non-AP MLD, and map the at least one TID of the latency sensitive traffic to a subset of the links established between the AP-MLD and the non-AP MLD through a negotiation process with the first STA.

[0148] In some embodiments, the TID-to-link mapping unit 1010 can be further configured to receive a TID-to-link mapping request from the first STA in the non-AP MLD, and transmit a TID-to-link mapping response to the first STA to map the at least one TID of the latency sensitive traffic to a link between the AP-MLD and the non-AP MLD to which the at least one TID of the latency sensitive traffic has not been mapped yet.

[0149] In some embodiments, the R-TWT establishing unit can be further configured to receive the R-TWT request from the first STA before transmitting the R-TWT response to the first STA. That is, the R-TWT protocol can be established through an unsolicited R-TWT response from the first AP or a solicited R-TWT response from the first AP.

[0150] In some embodiments, the R-TWT request and / or the R-TWT response can comprise an R-TWT element including a first subfield and a second subfield in a control field, wherein the first subfield is set to indicate whether information included in the R-TWT element is used for negotiation of parameters of the R-TWT, and the second subfield is set to indicate whether the information included in the R-TWT element is applied to all links to which the at least one TID of the latency sensitive traffic has been mapped.

[0151] In some embodiments, the R-TWT establishing unit 1020 can be further configured to receive an integrated R-TWT request from the first STA, and transmit an integrated R-TWT response to the first STA to map the at least one TID of the latency sensitive traffic to at least one link between the AP-MLD and the non-AP MLD to which the at least one TID of the latency sensitive traffic has not been mapped yet, and establish the R-TWT protocol on any one or more of the at least one link to which the at least one TID of the latency sensitive traffic has been mapped.

[0152] In some embodiments, the integrated R-TWT request and / or the integrated R-TWT response can be set to include at least one first R-TWT element indicating at least one link on which the R-TWT protocol is established and at least one TID-to-link mapping element indicating at least one TID of the latency sensitive traffic mapped to at least one link. Alternatively, in some embodiments, the integrated R-TWT request and / or the integrated R-TWT response can be set to include at least one second R-TWT element indicating one or more links on which the R-TWT protocol is established and at least one TID of the latency sensitive traffic mapped to at least one link. Figures 7A to 7C Three examples of the format of the Broadcast TWT Parameter Set field in the R-TWT element are shown in FIGS. 13A, 13B and 13C.

[0153] In some embodiments, the AP 1000 can further include a first R-TWT termination unit configured to tear down the R-TWT protocol established on the first link between the AP and the first STA if no TID of the latency sensitive traffic is mapped to the first link due to the TID-to-link mapping update.

[0154] In some embodiments, the AP 1000 can further include a second R-TWT termination unit configured to transmit, on the first link, an R-TWT SP silent element or a TID-to-link mapping element with a suspended R-TWT mode indication to enter the first link into a suspended TWT operation mode or a TID-to-link mapping element with an R-TWT termination mode indication to terminate the R-TWT protocol on the first link if the AP MLD and the non-AP MLD support a suspended R-TWT operation mode and no TID of the latency sensitive traffic is mapped to the first link established between the AP and the first STA. In some embodiments, the second R-TWT termination unit 1030B can be further configured to tear down the R-TWT protocol on the first link if a duration of the suspended R-TWT operation mode exceeds a predetermined threshold.

[0155] In some embodiments, the TID-to-link mapping element can include an R-TWT information field for the TID set to indicate whether at least one TID of the latency sensitive traffic is mapped to the plurality of links established between the AP MLD and the non-AP MLD and a status of the R-TWT operation, wherein the status of the R-TWT operation is set to indicate a suspended R-TWT operation mode, or an R-TWT termination mode, or an absent R-TWT mode.

[0156] Various embodiments of the present application also provide a STA for R-TWT operation for latency sensitive traffic in a WLAN. Figure 11 is a schematic diagram illustrating a STA 1100 according to some embodiments of the present application. Referring to Figure 11 , the STA 1100 can include a TID-to-link mapping request unit 1110 and an R-TWT request unit 1120. The TID-to-link mapping request unit 1110 can be configured to receive a first response from a first AP in an AP MLD to map at least one TID of latency sensitive traffic to at least one link established between the AP MLD and a non-AP MLD, where the AP MLD includes a plurality of APs including the first AP, and the non-AP MLD includes a plurality of non-AP STAs including the STA. The R-TWT request unit 1120 can be configured to receive an R-TWT response from the first AP to establish an R-TWT protocol on any one or more of the at least one link to which the at least one TID of latency sensitive traffic has been mapped.

[0157] In some embodiments, the TID-to-link mapping request unit 1110 can be further configured to send a first request to the first AP. That is, the first response from the first AP can be an unsolicited response or a solicited response.

[0158] In some embodiments, the TID-to-link mapping request unit 1110 can include a first transmission unit configured to send a first multi-link association request to the first AP, and a first reception unit configured to receive a first multi-link association response from the first AP to establish a plurality of links between APs in the AP MLD and STAs in the non-AP MLD, and to map all TIDs to all of the plurality of links established between the AP MLD and the non-AP MLD by default, where the all TIDs include the at least one TID for latency sensitive traffic.

[0159] Alternatively, in some embodiments, the TID-to-link mapping request unit 1110 can include a second transmission unit configured to send a second multi-link association request to the first AP, and a second reception unit configured to receive a second multi-link association response from the first AP to establish a plurality of links between APs in the AP MLD and STAs in the non-AP MLD, and to map the at least one TID of latency sensitive traffic to a subset of the links established between the AP MLD and the non-AP MLD through a negotiation process with the first AP.

[0160] In some embodiments, the TID-to-link mapping request unit 1110 can be further configured to send a TID-to-link mapping request to the first AP and receive a TID-to-link mapping response from the first AP to map the at least one TID of the latency sensitive traffic to a link between the AP MLD and the non-AP MLD that the at least one TID of the latency sensitive traffic has not been mapped to.

[0161] In some embodiments, the R-TWT request unit can be further configured to send the R-TWT request to the first AP before receiving the R-TWT response. That is, the R-TWT protocol can be established by an unsolicited R-TWT response from the first AP or a solicited R-TWT response from the first AP.

[0162] In some embodiments, the R-TWT request and / or the R-TWT response can include an R-TWT element including a first subfield and a second subfield in a control field, where the first subfield is set to indicate whether information included in the R-TWT element is for negotiation of parameters of the R-TWT and the second subfield is set to indicate whether information included in the R-TWT element is applied to all links to which the at least one TID of the latency sensitive traffic has been mapped.

[0163] In some embodiments, the R-TWT request unit 1120 can be further configured to send an integrated R-TWT request to the first AP and receive an integrated R-TWT response from the first AP to map the at least one TID of the latency sensitive traffic to at least one link between the AP-MLD and the non-AP MLD that the at least one TID of the latency sensitive traffic has not been mapped to and establish the R-TWT protocol on any one or more of the at least one link to which the at least one TID of the latency sensitive traffic has been mapped.

[0164] In some embodiments, the integrated R-TWT request and / or the integrated R-TWT response can be set to include at least one first R-TWT element indicating the at least one link on which the R-TWT protocol is established and at least one TID-to-link mapping element indicating the at least one link to which the at least one TID of the latency sensitive traffic is mapped.

[0165] Alternatively, in some embodiments, the integrated R-TWT request and / or the integrated R-TWT response can be set to include at least one second R-TWT element indicating one or more links on which the R-TWT protocol is established and the at least one link to which the at least one TID of the latency sensitive traffic is mapped. Figures 7A to 7CThree examples of the format of the Broadcast TWT Parameter Set field in the R-TWT element are shown in FIG. 13.

[0166] In some embodiments, the STA 1100 can further include a first R-TWT termination unit configured to tear down the R-TWT protocol established on the first link between the first AP and the STA if no TID of the latency sensitive traffic is mapped to the first link.

[0167] In some embodiments, the STA 1100 can further include a second R-TWT termination unit configured to, if the AP MLD and the non-AP MLD support a suspended R-TWT operation mode and no TID of the latency sensitive traffic is mapped to the first link established between the first AP and the STA, enter the first link into the suspended TWT operation mode upon receiving a R-TWT SP silent element or a TID-to-link mapping element with a suspended R-TWT mode indication sent by the first AP on the first link, or terminate the R-TWT protocol on the first link upon receiving a TID-to-link mapping element with a R-TWT termination indication sent by the first AP on the first link. Preferably, the second R-TWT termination unit can be further configured to tear down the R-TWT protocol on the first link if a duration of the suspended R-TWT operation mode exceeds a predetermined threshold.

[0168] In some embodiments, the TID-to-link mapping element includes an R-TWT information field for the TID, which is set to indicate whether at least one TID of the latency sensitive traffic is mapped to a plurality of links established between the AP MLD and the non-AP MLD, and a status of the R-TWT operation, wherein the status of the R-TWT operation is set to indicate a suspended R-TWT operation mode, or a R-TWT termination mode, or an absent R-TWT mode.

[0169] Various embodiments of the present disclosure also provide an AP for R-TWT operation for latency sensitive traffic in a WLAN. The AP can include a memory for storing instructions for executing a first method for R-TWT operation for latency sensitive traffic in a WLAN, and a processor communicatively coupled with the memory, the processor configured to execute the instructions to perform the first method for R-TWT operation for latency sensitive traffic in a WLAN as described in various embodiments of the present disclosure.

[0170] Various embodiments of the application also provide a STA for R-TWT operation for latency sensitive traffic in a WLAN. The STA can include a memory for storing instructions for executing a second method for R-TWT operation for latency sensitive traffic in a WLAN; and a processor communicably coupled with the memory, the processor configured to execute the instructions to perform the second method for R-TWT operation for latency sensitive traffic in a WLAN as described in the various embodiments of the application.

[0171] Various embodiments of the application also provide a computer program product comprising instructions for causing a computer to perform any of the methods for R-TWT operation for latency sensitive traffic in a WLAN according to any of the embodiments of the application when the instructions are executed on the computer.

[0172] Various embodiments of the application also provide a computer program comprising instructions for causing a computer to perform the method for R-TWT operation for latency sensitive traffic in a WLAN according to any of the embodiments of the application when the instructions are executed on the computer.

[0173] Various embodiments of the application also provide a non-transitory storage medium comprising computer program code which, when executed on a computer, is for causing the computer to perform the method for R-TWT operation for latency sensitive traffic in a WLAN according to any of the embodiments of the application.

[0174] Various embodiments of the application also provide a chip configured to perform the method for R-TWT operation for latency sensitive traffic in a WLAN according to any of the embodiments of the application.

[0175] At least some of the steps of the method for R-TWT operation for latency sensitive traffic in a WLAN according to any of the embodiments of the application described above can be implemented with hardware, a processor executing firmware instructions, a processor executing software instructions, or any combination thereof. When implemented with a processor executing software or firmware instructions, the software or firmware instructions can be stored in any computer-readable memory such as, for example, magnetic disks, optical disks, or other storage media, stored in RAM or ROM or flash memory, a processor, a hard disk drive, an optical disk drive, a tape drive, etc. Likewise, the software or firmware instructions can be transferred to a user or a system via any known or desired transfer method, including, for example, on a computer readable disk or other portable computer storage mechanism, or via a communication medium.

[0176] As described above, various embodiments of the present application provide an efficient mechanism for R-TWT operation for latency sensitive traffic in WLAN to further optimize the spectral efficiency, improve the throughput and reduce the power consumption of the WLAN. With the methods and devices provided in the embodiments of the present application, the mapping of TIDs to links can be performed as a default procedure during or after the multi-link setup procedure, a negotiation procedure together with the multi-link setup procedure, a separate negotiation procedure after the multi-link setup procedure, or a negotiation procedure integrated with the R-TWT setup procedure, depending on the actual needs of the communication system.

[0177] It is to be understood that the embodiments and features described above are to be considered illustrative rather than restrictive. Numerous other embodiments will become apparent to those skilled in the art upon consideration of the specification and practice of the application. Accordingly, the scope of the application should be determined by the appended claims, and their full scope of equivalents, not by the foregoing description. Furthermore, certain terms are used for the sake of clarity only and are not intended to limit the scope of the embodiments of the present application.

Claims

1. A method for restricted target wake time, R-TWT, operation for latency sensitive traffic in a wireless local area network, WLAN, the method comprising: sending, by a first station, STA, in a non-access point multi-link device, AP MLD, a first request to a first access point, AP, from the AP MLD; receiving, by the first STA, a first response of the first AP to map at least one traffic identifier, TID, of latency sensitive traffic to at least one link established between the AP MLD and the non-AP MLD, wherein the AP MLD comprises a plurality of APs and the non-AP MLD comprises a plurality of non-AP STAs; and receiving, by the first STA, an R-TWT response to establish an R-TWT protocol on any one or more of the at least one link to which the at least one TID of latency sensitive traffic has been mapped. the sending the first request comprises:

2. The method of claim 1, wherein, sending, by the first STA, a first multi-link association request to the first AP, and the receiving the first response comprises: receiving, by the first STA, a first multi-link association response from the first AP to establish a plurality of links between APs in the AP MLD and STAs in the non-AP MLD and to map all TIDs, including the at least one TID of latency sensitive traffic, to all links established between the AP MLD and the non-AP MLD by default. the sending the first request comprises: sending, by the first STA, a second multi-link association request from the first STA, and the receiving the first response comprises: receiving, by the first STA, a second multi-link association response from the first AP to establish a plurality of links between APs in the AP MLD and STAs in the non-AP MLD and to map the at least one TID of latency sensitive traffic to a subset of links established between the AP MLD and the non-AP MLD through a negotiation process with the first AP.

3. The method of claim 1, wherein, 4. The method of claim 3, further comprising: sending, by the first STA, a TID-to-link mapping request to the first AP; and receiving, by the first STA, a TID-to-link mapping response from the first AP to map the at least one TID of latency sensitive traffic to a link between the AP MLD and the non-AP MLD to which the at least one TID of latency sensitive traffic has not been mapped. sending, by the first STA, an R-TWT request to the first AP prior to receiving the R-TWT response. ​ 5. The method of any one of claims 1 to 4, further comprising: ​ 6. The method of claim 5, wherein, The R-TWT request and / or the R-TWT response includes an R-TWT element including a first subfield and a second subfield in a control field, wherein the first subfield is set to indicate whether information included in the R-TWT element is for negotiation of parameters of the R-TWT, and the second subfield is set to indicate whether the information included in the R-TWT element is applied to all links to which the at least one TID of latency sensitive traffic has been mapped.

7. The method of claim 5, wherein, The sending the R-TWT request includes: sending, by the first STA, an integrated R-TWT request to the first AP; and The receiving the R-TWT response includes: receiving, by the first STA, an integrated R-TWT response from the first AP to map the at least one TID of latency sensitive traffic to at least one link between the AP MLD and the non-AP MLD to which the at least one TID of latency sensitive traffic has not been mapped, and establishing an R-TWT protocol on any one or more of the at least one link to which the at least one TID of latency sensitive traffic has been mapped.

8. The method of claim 7, wherein, The integrated R-TWT request and / or the integrated R-TWT response is set to include at least one first R-TWT element indicating the at least one link on which the R-TWT protocol is established and at least one TID-to-link mapping element indicating the at least one link to which the at least one TID of latency sensitive traffic is mapped.

9. The method of claim 7, wherein, The integrated R-TWT request and / or the integrated R-TWT response is set to include at least one second R-TWT element indicating the one or more links on which the R-TWT protocol is established and the at least one link to which the at least one TID of latency sensitive traffic is mapped.

10. The method of claim 9, wherein, The second R-TWT element includes a broadcast R-TWT parameter set field set to include a first subfield, a second subfield, and a third subfield, the first subfield indicating at least one link to which the R-TWT is applied, the second subfield indicating at least one link on which frames belonging to TIDs of latency sensitive traffic in a downlink direction are transmitted, and the third subfield indicating at least one link on which frames belonging to TIDs of latency sensitive traffic in an uplink direction are transmitted.

11. A station (STA) for restricted target wake time (R-TWT) operation of latency sensitive traffic in a wireless local area network (WLAN), the STA comprising: a memory for storing instructions for performing the method for R-TWT operation for latency sensitive traffic in a WLAN according to any one of claims 1 to 10; and a processor communicatively coupled with the memory, the processor configured to execute the instructions stored in the memory to perform the method for R-TWT operation for latency sensitive traffic in a WLAN. a memory for storing instructions for performing the method for R-TWT operation for latency sensitive traffic in a WLAN according to any one of claims 1 to 10; and a processor communicatively coupled with the memory, the processor configured to execute the instructions stored in the memory to perform the method for R-TWT operation for latency sensitive traffic in a WLAN.

Images