CN112788791A - Multi-link channel access method - Google Patents

Abstract

Translated fromChinese

一个装置(如，存取点(AP))建立包括主要链路以及至少一个辅助链路的多个链路。所述装置在所述主要链路上传输管理帧来指示所述AP的多链路性能。所述装置通过所述主要链路上的关联进程用多链路性能以及操作参数为一个或多个非AP站(STA)配置所述辅助链路，所述一个或多个非AP STA能够在所述主要链路以及辅助链路上操作。

A device (eg, an access point (AP)) establishes multiple links including a primary link and at least one secondary link. The apparatus transmits a management frame on the primary link to indicate the multi-link capability of the AP. The apparatus configures the secondary link for one or more non-AP stations (STAs) with multilink capabilities and operating parameters through an association process on the primary link, the one or more non-AP STAs capable of Operates on the primary link as well as the secondary link.

Description

Multi-link channel access method

Technical Field

The present invention relates generally to wireless communications, and more particularly to enhanced high-throughput (EHT) multilink channel access and operation.

Background

Unless otherwise indicated herein, the approaches described in this section are not background to the claims set forth below and are not admitted to be background by inclusion in this section.

In a Wireless Local Area Network (WLAN), a Station (STA) capable of multilink transmission needs to access any one of the multiple links to satisfy an EHT Project Authorization Request (PAR) with respect to the Institute of Electrical and Electronics Engineers (IEEE)802.11 standard as long as one or more of the multiple links are available. Due to in-device coexistence (IDC) (e.g., between 5GHz and 6GHz bands) interference, multilink performance may not be efficiently utilized in situations where an Access Point (AP) capable of multilink operation has constraints on receiving and transmitting frames synchronously in the multilink due to IDC interference. For example, when an AP performs frame exchange with one or more STAs on one link, then other relevant STAs will not transmit on another link even if this channel is idle to these STAs, otherwise the AP may be subject to IDC interference. One approach to solving this problem may force STAs that detect frame exchanges from their own Basic Service Set (BSS) on one link to defer backoff or perform an internal collision resolution approach on another link that has IDC constraints with the transmitting link. However, this would result in an under-utilization of the multilink resources. Therefore, there remains a need for a solution for avoiding IDC interference problems while efficiently utilizing multi-link resources without forcing STAs to defer backoff (backoff) or perform internal collision solutions for channel access on links with constraints.

Disclosure of Invention

The following summary is illustrative only and is not intended to be in any way limiting. That is, the following summary is provided to introduce concepts, points, benefits and advantages of the non-obvious techniques described herein. Selected embodiments are further described in the detailed description below. Accordingly, the following summary is not intended to identify essential features of the claimed subject matter, nor is it intended for use in determining the scope of the claimed subject matter.

It is an object of the present invention to provide schemes, concepts, designs, techniques, methods and apparatus relating to EHT multilink channel access and operation. Under the proposed scheme according to the present invention, it is believed that IDC interference problems can be avoided while efficiently utilizing multi-link resources without forcing STAs to defer back or performing internal collision resolution methods for channels on multiple links with constraints.

In one aspect, a method may involve establishing, by a processor of a device implemented in an Access Point (AP), a plurality of links including a primary link and at least one secondary link. The method also involves transmitting, by the processor, a management frame over the primary link to indicate multi-link performance of the AP. The method may further involve configuring, by the apparatus, the secondary link with multi-link performance and operating parameters for one or more non-AP Stations (STAs) capable of operating on the primary link and the secondary link through an association process on the primary link.

In another aspect, a method involves receiving, by a processor of an apparatus implemented at a Station (STA), a management frame from an Access Point (AP) on a primary link of a plurality of links, the plurality of links including the primary link and at least one secondary link, the management frame indicating multi-link performance of the AP, the AP capable of operating on the primary link and the secondary link. The method also involves executing, by the processor, an association process on the primary link. The method may further involve the processor receiving a setup configuration from the AP at the primary link, setting up the secondary link.

Notably, while the description provided herein may be in the context of certain radio access technologies, networks, and network topologies (e.g., WIFI), the proposed concepts, schemes, and any variations/derivations may be implemented in, for, and by other types of radio access technologies, networks, and network topologies, such as, for example and without limitation, bluetooth, ZigBee, 5 th generation (5G)/New Radio (NR), Long Term Evolution (LTE), LTE-Advanced pro, internet of things (IoT), industrial IoT (iiot), and narrowband IoT (NB-IoT). Accordingly, the scope of the invention is not limited to the examples described herein.

Drawings

The accompanying drawings are provided to include a further understanding of the invention and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and together with the description serve to explain the principles of the invention. It is to be understood that the drawings are not necessarily drawn to scale, since some of the elements are shown out of scale in the practice of the invention to clearly illustrate the principles of the invention.

FIG. 1 sets forth a diagram of an exemplary network environment in which various solutions and schemes according to embodiments of the present invention may be implemented.

Fig. 2 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 3 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 4 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 5 illustrates an exemplary format according to an embodiment of the present invention.

Fig. 6 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 7 illustrates an exemplary format according to an embodiment of the present invention.

Fig. 8 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 9 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 10 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 11 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 12 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 13 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 14 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 15 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 16 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 17 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 18 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 19 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 20 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 21 shows an exemplary scenario according to an embodiment of the present invention.

Fig. 22 shows a block diagram of an exemplary communication system in accordance with an embodiment of the present invention.

FIG. 23 illustrates a flow diagram of an exemplary process according to an embodiment of the invention.

FIG. 24 shows a flowchart of an exemplary process according to an embodiment of the present invention.

Detailed Description

Specific embodiments and implementations of the claimed subject matter are disclosed herein. However, it is to be understood that the disclosed embodiments and implementations are merely illustrative of the claimed subject matter, which can be embodied in various forms. This invention may, however, be embodied in many different forms and should not be construed as limited to the exemplary embodiments and implementations set forth herein. Rather, these exemplary embodiments and implementations are provided so that this description of the invention is thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the following description, well-known features and technical details may be omitted to avoid unnecessarily obscuring the embodiments and the implementation of the invention.

Embodiments in accordance with the present invention relate to various techniques, methods, schemes and/or solutions relating to EHT multilink channel access and operation in wireless communications. The various possible solutions according to the invention can be implemented individually or jointly. That is, although the possible solutions are described below separately, one or both of the possible solutions may be implemented in one or another combination.

Fig. 1 illustrates anexemplary network environment 100 in which various solutions and schemes according to the present invention may be implemented. Fig. 2-21 illustrate exemplary embodiments of various proposed schemes in anetwork environment 100 according to the present invention. Subsequent descriptions of various proposed schemes are provided with reference to fig. 1-21.

Referring to section (a) of fig. 1,network environment 100 may involve at least one STA110 andSTA 115 associated with and in wireless communication with an AP120 in aBSS 130 according to one or more IEEE 802.11 standards. Each STA110 (interchangeably labeled herein as "STA 1") and STA 115 (interchangeably labeled herein as "STA 2") may be a multi-link STA having one or more links operating in, for example, but not limited to, a 2.4GHz band, a 5GHz band, and/or a 6GHz band. Similarly, AP120 may be multi-link capable and therefore may communicate with STA110 and/orSTA 115 over one or more links (e.g., link 1 and link 2). Under various proposed schemes according to the present invention, STA110,STA 115, and AP120 may be used to perform EHT multilink channel access and operations in wireless communications according to various proposed schemes of the present invention described below.

Referring to part (B) of fig. 1, assuming thatlink 1 andlink 2 have IDC interference, when STA110 obtains a channel or transmission opportunity (TXOP) onlink 1, STA110 may transmit a frame to AP120 in the obtained channel/TXOP onlink 1.STA 115 still contends for the other link (e.g., link 2) to meet the low latency requirement in the transmission. When theSTA 115 obtains a channel or TXOP onlink 2, theSTA 115 may transmit frames to the AP120 on the obtained channel/TXOP onlink 2. However, in the event that AP120 has constraints on the reception and transmission frames synchronized across multiple links (e.g., link 1 and link 2) due to IDC interference (e.g., in the 5GHz and 6GHz bands), aggregated Medium Access Control (MAC) protocol data units (a-MPDUs) or Physical Layer Convergence Process (PLCP) protocol data units (PPDUs) transmitted bySTA 115 may not be correctly received by AP120 due to IDC interference when AP120 needs to provide a feedback Block Acknowledgement (BA) to STA110 onlink 1.

As explained further below, under one or more various proposed schemes for EHT multilink channel access and operation in accordance with the present invention, an AP (e.g., AP 120) having constrained multilink capability for transmission and reception (TX/RX) that is synchronized on different links may follow certain rules. For example, the AP120 may set up theBSS 130 and transmit management frames (e.g., beacons, probe responses) on the primary link (primary link) to indicate the multi-link performance of the AP120 to the STAs (e.g., STA110 and SAT 115) in theBSS 130. The AP120 may allow legacy STAs and EHT STAs that are not capable of multi-link operation to associate with the AP only on the primary link, not the secondary link. The AP120 may also configure one or more secondary links to be enabled for trigger-based UL transmissions and disabled for Enhanced Distributed Channel Access (EDCA) UL transmissions. Further, a TXOP initiated on a primary link (interchangeably referred to herein as a "triggered TXOP") may trigger a TXOP on a secondary link (interchangeably referred to herein as a "triggered TXOP"). Furthermore, the triggered TXOP and the triggered TXOP may be synchronized. Furthermore, the end point of a triggered TXOP on the secondary link may be limited by the end point of the triggered TXOP on the primary link.

As disclosed below, under one or more various proposed schemes for EHT multilink channel access and operation in accordance with the present invention, a non-AP STA (e.g., STA110 or STA 115) having multilink capability with TX/RX constraints on synchronization on different links may follow certain rules. For example,STA 110/STA 115 may only contend for the medium on the primary link. Further,STA 110/STA 115 may monitor the secondary link configured for trigger frames (trigger frames). Further,STA 110/STA 115 may request to be triggered on the configured secondary link. Further,STA 110/STA 115 may not respond to a trigger frame addressed to it on the secondary link unless it has performed a Clear Channel Assessment (CCA) untilSTA 110/STA 115 detects a frame whose Network Allocation Vector (NAV) may be set, or until a period equal to a predetermined delay has elapsed, whichever is earlier.

Under the proposed scheme according to the present invention, the AP120 may set a primary link and one or more secondary links among a plurality of links. For example, AP120 may transmit management frames (e.g., beacons) as well as other management frames over the primary link. In addition, AP120 may configure the performance and operating parameters of the secondary link with multiple links for its associated STAs (including STA110 and STA 115) via the primary link. In addition, the AP120 may transmit short beacons (short beacons) on the secondary link, each with a time stamp (time stamp) and BSS identifier information.

Under the proposed scheme, where the AP120 cannot support synchronized transmission and reception on the primary link and the at least one secondary link, respectively, the AP120 may indicate in the configuration for the secondary link the following: (a) channel access based on UL triggers is enabled; and (b) channel access based on Distributed Coordination Function (DCF) and/or EDCA contention is disabled. For example, the AP120 may configure the secondary link for UL triggering to be based only on the trigger, and there will be no allowed channel contention on this secondary link. Further, AP120 may trigger its associated STAs (including STA110 and STA 115) to perform UL transmissions on the secondary link in at least one of a number of ways. The first approach would involve the AP120 contending for the medium directly on the secondary link for transmission of the UL trigger frame. The second approach would involve initiation by the relevant STA (e.g., STA110 or STA 115) via a trigger request indication (e.g., a reverse exchange indication) in the ongoing PPDU on the primary link. A third approach would involve multi-link acknowledgement by the AP120 with trigger information or BA plus multi-trigger on the primary link or on both the primary and secondary links.

Under the proposed scheme according to the present invention, relevant STAs with multiple link capabilities (e.g., STA110 and STA 115) may stay on the primary link. For example, a given non-AP STA (e.g., of STA110 or STA 115) may associate with AP120 over a primary link and may indicate its multi-link performance. The primary link to the non-AP STA may be the link on which the non-AP STA associates with or resides on theAP 120. non-AP STAs may support multiple radios or a single radio. Further, the non-AP STA may or may not support synchronized transmission and reception.

Under the proposed scheme, a given non-AP STA (e.g., STA110 or STA 115) may configure one or more secondary links over a primary link. For example, for each secondary link, the non-AP STA may be configured for UL channel access, such as trigger-based channel access only or contention-based channel access only, or both. In the event that the AP120 cannot accommodate synchronized transmission and reception on the primary link and the particular secondary link, then the particular secondary link may be configured for UL channel access, as based on triggers only. Unless the channel access policy is explicitly indicated, there is no limitation on the channel access method on the primary link for non-AP STAs.

Under the proposed scheme, a given non-AP STA (e.g., STA110 or STA 115) may contend for medium for channel access on the primary link and/or the secondary link, which is not indicated as being based on only the triggered UL. Further, when the secondary link is only indicated as trigger-based UL, the non-AP STA may monitor trigger frames or trigger information on the primary link and/or the secondary link for the non-AP STA to transmit UL data on the secondary link. For example, a non-AP STA with multiple radios may perform CCA detection only on the secondary link for NAV setting and resetting on the link without attempting to decode the packet when: (a) the AP120 indicates that a trigger frame or trigger information is to be sent only on the primary link, or (b) the non-AP STA indicates to enter a low power mode (e.g., perform CCA detection only on the secondary link by keeping the primary link fully on). In addition, a non-AP STA with multiple radios may keep monitoring the primary link to decode packets including trigger information.

Under the proposed scheme according to the present invention, an ongoing TXOP of intra-BSS frame exchange on the primary link may trigger a secondary TXOP on the secondary link. Under the proposed scheme, the ongoing TXOP of an intra-frame BSS frame exchange may be initiated by AP120 or a non-AP STA (e.g., STA110 or STA 115). Under the proposed scheme, when the TXOP initiator is a non-AP STA, one or more of the multiple operations may be performed separately or in combination. In one operation, a TXOP initiator (e.g., STA110 or STA 115) may indicate a grant (e.g., a link Identifier (ID) bitmap) for AP120 to trigger a TXOP that begins UL transmissions by entities and/or other non-AP STAs on the primary link and/or the secondary link. For example, the TXOP initiator may indicate the buffer status of one or more Traffic IDs (TIDs) for traffic flows, bandwidth requirements, and preferred/available link IDs. In another operation, a TXOP responder (e.g., AP 120) may respond to a TXOP initiator with an acknowledgement, trigger information, and/or information with or without a grant of the TXOP initiator. For example, the AP120 may trigger one or more non-AP STAs for UL transmission on the primary link and/or the secondary link. Further, the trigger or trigger information may be sent on the primary link or both the primary and secondary links. Under the proposed scheme, the trigger indication may indicate one or more of the following information: (a) a link ID for one or more specific non-AP STAs to monitor for triggers on a specific link; (b) a target time for one or more particular non-AP STAs to receive a trigger; and (c) resource scheduling information and/or transmission parameters.

Fig. 2 shows anexemplary scenario 200 according to an embodiment of the present invention. Incase 200, STA110 (labeled "STA 1" in fig. 2), as the TXOP initiator, may transmit a first PPDU (labeled "PPDU 1" in fig. 2) indicating a grant for AP120 to trigger STA110 (optionally STA 115) for UL transmission on one or both of a primary link (labeled "P-link" in fig. 2) and a secondary link (labeled "S-link" in fig. 2). In response, in response to receiving the first PPDU, the AP120 may transmit a multi-link block acknowledgement (ML-BA) on both the primary link and the secondary link to request synchronized UL transmissions on the P-link and the S-link. Accordingly, STA110 may transmit a second PPDU (labeled "PPDU 2" in fig. 2) on the primary link and a third PPDU (labeled "PPDU 3" in fig. 2) on the secondary link. Upon receiving PPDU2 and PPDU3, AP120 may transmit BAs on each of the primary link and the secondary link.

Under the proposed scheme, when the TXOP initiator is AP120, the TXOP initiator may trigger one or more TXOP responders (e.g., STA110 and/or STA 115) for UL transmissions on the primary link and/or the secondary link. For example, a trigger or trigger information may be sent on the primary link to trigger the non-AP STA to transmit on the secondary link. Alternatively, the trigger or trigger information may be transmitted on the primary link to instruct one or more target non-AP STAs to receive the trigger on the secondary link.

Under the proposed scheme, a TXOP responder (e.g., STA110 or STA 115) may respond to a TXOP initiator with a UL trigger based PPDU on the primary link and request a trigger on the secondary link. For example, a TXOP responder may not respond to a trigger frame addressed to it on the secondary link unless the TXOP responder has performed a CCA until the TXOP responder detects a frame that can set its NAV, or until a period of time equal to a predetermined delay has elapsed, whichever is earlier.

Fig. 3 shows anexemplary scenario 300 according to an embodiment of the present invention. Inscenario 300, STA110 (labeled "STA 1" in fig. 3) (as a TXOP responder) may receive a multi-link UL trigger from AP120 (as a TXOP initiator) as a TXOP initiator. Thus, STA110 may transmit a trigger-based first PPDU (labeled "PPDU 1" in fig. 3) over the primary link and a BA followed by a multi-link trigger over each of the primary link (labeled "P-link" in fig. 3) and the secondary link (labeled "S-link" in fig. 3). In response, STA110 may transmit a trigger-based second PPDU (labeled "PPDU 2" in fig. 3) on the primary link and a trigger-based third PPDU (labeled "PPDU 3" in fig. 3) on the secondary link. Upon receiving PPDU2 and PPDU3, AP120 may transmit BAs on each primary link as well as the secondary link.

Under the proposed scheme according to the present invention, the end point of the triggered TXOP on the secondary link may be at the same time or earlier than the end point of the triggered TXOP on the primary link. Under the proposed scheme, triggering a TXOP and the triggered TXOP may be synchronized during the triggered TXOP. For example, PPDUs on the primary link and the secondary link may be aligned during the trigger TXOP. In addition, synchronized transmission and reception on the primary and secondary links may be supported. In addition, there is no Point Coordination Function (PCF) inter-frame space (PIFS) on the secondary link to resume transmission.

Fig. 4 shows anexemplary scenario 400 according to an embodiment of the present invention. Inscenario 400. STA110 (labeled "STA 1" in fig. 4) may transmit a first PPDU (labeled "PPDU 1" in fig. 4) indicating a grant for AP120 to trigger STA110 (and, optionally, STA 115) for UL transmissions on each or both of the primary link (labeled "P-link" in fig. 4) and the secondary link (labeled "S-link" in fig. 4). In response, in response to receiving the first PPDU, the AP120 may transmit a control frame (e.g., ML-BA) on both the primary link and the secondary link to request UL transmissions synchronized on the P-link and the S-link. Thus, STA110 may transmit a second PPDU (labeled "PPDU 2" on fig. 4) on the primary link and a third PPDU (labeled "PPDU 3" on fig. 4) on the secondary link. Upon receiving PPDU2 and PPDU3, AP120 may transmit BAs on each primary link as well as the secondary link. Further, STA110 may transmit a fourth PPDU (labeled as "PPDU 4" in fig. 4) on the primary link, which may be followed by a BA from AP120 on the primary link. Inscenario 400, a triggered TXOP on a secondary link and a triggered TXOP on a primary link may be synchronized and both may end at the same time.

Under the proposed scheme according to the present invention, the ML-BA may be one of a plurality of possible formats. FIG. 5 shows an exemplary format 500 (not to scale) according to an embodiment of the invention. Referring to fig. 5, in a first option (option 1), the ML-BA may include a link ID bitmap. Further, the multilink type bit in the BA control field may indicate ML-BA. Further, a link ID bitmap field with a value of "1" on the corresponding bit may indicate that the link is to be triggered (and a value of "0" may indicate that the link is not to be triggered). In addition, the UL PPDU length field may indicate the length of the next trigger-based PPDU.

Fig. 6 illustrates anexemplary scenario 600 according to an embodiment of the present invention. Referring to fig. 6, in the second option (option 2), a BA or an Acknowledgement (ACK) may be serialized with a multilink trigger variable. For example, the trigger type may be a multi-link trigger. Further, the multi-link trigger may include a link ID bitmap indicating which link of the plurality of links is to be triggered. Further, the multi-link trigger may include a common PPDU length scheduled for a next PPDU on the multiple links. Further, the BA/ACK and the multi-link trigger may be aggregated in one A-MPDU.

FIG. 7 shows an exemplary format 700 (not to scale) according to an embodiment of the invention. Referring to fig. 7, in the second option (option 2), the period field may be set link by link and the Receiver Address (RA) may be set to the MAC address of each receiving link. Further, the Transmitter Address (TA) may be a MAC address of the STA which transmits the trigger frame. In addition, the common information field may include a trigger type subfield and an UL length subfield. For example, the UL length in the common information field of the trigger frame may include a common PPDU length for a subsequent PPDU. Further, the user information field may contain at least one link ID bitmap indicating the links to be triggered.

Fig. 8 shows anexemplary scenario 800 according to an embodiment of the present invention. Inscenario 800, AP120 may be multi-link capable but AP120 may not perform TX/RX synchronously on its multiple links. The AP120 may configure the primary link (0 labeled "P-link" in fig. 8) and transmit management frames (e.g., beacons, probe frames) over the primary link to indicate its multi-link performance. Since synchronized TX/RX is not supported on different links, the AP120 may also configure one or more auxiliary links (labeled "S-link" in fig. 8) for trigger-based UL enablement and EDCA UL disablement. Inscenario 800, STA110 (labeled "STA 1" in fig. 8) may only be associated with AP120 over the primary link. AP120 may configure the secondary link for STA110 with the operating parameters of the secondary link through the primary link. STA110 may contend for the channel only over the primary link. When STA110 obtains a TXOP on the primary link, STA110 may indicate a secondary link request in a first PPDU (labeled "PPDU 1" in fig. 8) with a link ID bitmap or indication. STA110 may also indicate its buffer status and bandwidth requirements. In response to receiving the first PPDU, the AP120 may request synchronized UL transmissions on the P-link and the S-link in response to receiving the first PPDU on both the primary link and the secondary link with trigger information in a control frame (e.g., ML-BA). Thus, STA110 may be triggered to transmit a second PPDU (labeled "PPDU 2" in fig. 8) and a third PPDU (labeled "PPDU 3" in fig. 8) on both the primary link and the secondary link. The TXOP on the secondary link may be limited by the TXOP duration of the primary link.

Fig. 9 shows anexemplary scenario 900 according to an embodiment of the invention. Inscenario 900, the AP120 may be multi-link capable and may configure a primary link (labeled "P-link" in fig. 9) and transmit management frames (e.g., beacons, probe frames) on the primary link to indicate its multi-link performance. Inscenario 900, STA110 (labeled "STA 1" in fig. 9) and STA 115 (labeled "STA 2" in fig. 9) may associate with AP120 on the primary link and each may indicate its multi-link performance on the primary link. AP120 may configure one or more secondary links (labeled "S-links" in fig. 9) for each STA110 andSTA 115, respectively, with the operating parameters of the secondary link over the primary link. Inscenario 900, the AP120 may not transmit and receive simultaneously and may configure the secondary link to trigger-based UL enabling and EDCA UL disabling. Further, STA110 andSTA 115 may contend for the channel only over the primary link. When STA110 obtains a TXOP on the primary link, STA110 may indicate a secondary link request in a first PPDU (labeled "PPDU 1" in fig. 9). When the secondary link is detected to be idle, in response to receiving the first PPDU, the AP120 may request synchronized transmissions on the P link and the S link in response to receipt of the first PPDU by transmitting trigger information in a control frame (e.g., ML-BA) on both the primary link and the secondary link. In response to the trigger, STA110 and/orSTA 115 may be triggered to transmit a third PPDU (labeled "PPDU 3" in fig. 9) and a fourth PPDU (labeled "PPDU 4" in fig. 9), respectively, on the secondary link. In addition, STA110 may also transmit a second PPDU (labeled as "PPDU 2" in fig. 9) on the primary link.STA 115 may still be triggered by AP120 at the primary link and/or the secondary link when STA110 does not indicate a secondary link request in the first PPDU. The triggered TXOP may be limited by the duration of the TXOP on the primary link. Further, AP120 may respond to the receipt of the second, third, and fourth PPDUs on the link and on a particular link with a BA, or to a joint BA/multi-TID BA for STA110 on the primary link and transmit the BA forSTA 115 on the secondary link.

Inscenario 900, idle detection on a link (e.g., a secondary link) may be performed in one or more ways that can be implemented separately or in combination. For example, the AP120 may check the NAV status on the secondary link, and in the case of NAV of 0, then the AP120 may decide that the secondary link is virtual Carrier Sense (CS) idle. Alternatively, the AP120 may initiate a new EDCA backoff process or continue the existing EDCA backoff process and perform a full CCA (e.g., random backoff with Packet Detection (PD) and power detection (ED) thresholds on the primary 20MHz channel of the secondary channel). Alternatively, the AP120 may perform PIFS detection on the secondary channel of the secondary link and, in the event that the channel is idle during the PIFS time, then the AP120 may decide that the secondary channel of the secondary link is physically CS idle. Alternatively, the AP120 may perform PIFS detection on the primary channel of the secondary link and, in the event that the channel is idle during the PIFS time, then the AP120 may decide that the primary channel of the secondary link is physically CS idle. Alternatively, the AP120 may perform EDCA backoff at some starting point (e.g., a starting time of backoff according to a value of a backoff count randomly selected by the AP 120).

Fig. 10 shows anexemplary scenario 1000 according to an embodiment of the present invention. Inscenario 1000, the AP120 may be multi-link capable and may configure the primary link (labeled "P-link" in fig. 10) and transmit management frames (e.g., beacons, probe responses) on the primary link to indicate its multi-link performance at TX/RX with no synchronization. Inscenario 1000, STA110 (labeled "STA 1" in fig. 10) and STA 115 (labeled "STA 2" in fig. 10) may associate with AP120 on the primary link and each may indicate its multi-link performance on the primary link. AP120 may configure one or more secondary links (labeled "S-links" in fig. 10) for STA110 andSTA 115 with the operating parameters of the secondary links over the primary link. Inscenario 900, the AP120 may configure the secondary link to be trigger-based UL enabled and EDCA UL disabled. Further, AP120 may acquire the channel over the primary link and transmit a multi-link UL trigger toSTA 110. The multi-link UL trigger may indicate resource allocation for STA110 andSTA 115 to transmit the first PPDU (labeled "PPDU 1" in fig. 10) and the second PPDU (labeled "PPDU 2" in fig. 10), respectively. The multi-link UL trigger may indicate a link ID to trigger STA110 and/orSTA 115 to transmit on the primary link and/or the secondary link in a subsequent frame exchange. Thus, STA110 and/orSTA 115 may transmit the first PPDU and the second PPDU with link IDs, respectively, to indicate the available links. STA110 and/orSTA 115 may also include buffer status and/or bandwidth requirements in the first PPDU and the second PPDU, respectively, where the link ID indicates the available links. In response to receiving the first PPDU, STA110 andSTA 115 may receive control frames (e.g., ML-BAs) over the primary link and the secondary link to request UL transmissions that are synchronized over the P-link and the S-link. STA110 may then transmit a third PPDU (labeled "PPDU 3" in fig. 10) on the primary link andSTA 115 may transmit a fourth PPDU (labeled "PPDU 4" in fig. 10) on the secondary link. Subsequent frame exchanges on the primary link as well as the secondary link may be synchronized. The TXOP triggered on the secondary link may be limited by the duration of the TXOP on the primary link.

Notably, for an AP capable of multi-link operation (e.g., AP 120), there are synchronous TX/RX constraints for some link pairs (pair of links). For example, in the worst case, DL transmissions on one link and UL transmissions on another link may overlap most of the time. Furthermore, when there are some legacy STAs (e.g., STAs that do not support multi-link operation), it is difficult for the AP to coordinate transmissions on both links. Therefore, to improve the link spectral efficiency with IDC interference problems, the present invention proposes a number of rules as described below to avoid simultaneous DL and UL transmissions on both links.

Under the proposed scheme according to the present invention, for a multi-link STA, the AP120 may configure one link as a primary link or a P-link and the other link as a secondary link or an S-link. Under the proposed scheme, legacy STAs or STAs that are not capable of multi-link operation may be allowed to associate on the P-link only. For example, the AP may set BSS members as multi-link capable devices that are only indicated in certain management frames (e.g., beacons, probe responses, etc.) on the secondary link, and/or the AP may transmit management frames on the secondary link using a PPDU format (e.g., EHT PPDU) that legacy STAs cannot decode, or the AP may not transmit certain management frames (e.g., beacons) on the secondary link. Under the proposed scheme, EDCA channel contention may be allowed on the P-link for DL as well as UL transmissions. Furthermore, in the following description of the present invention, with some other exceptions, EDCA channel contention on the S-link is only allowed for the AP120 to trigger UL transmissions. For example, EDCA channel contention may be allowed for non-AP STAs (e.g., STA110 and STA 115) on the S-link when AP120 has no DL transmissions on the P-link for a period of time (e.g., at light DL traffic load and heavy UL traffic load). Under the proposed scheme, DL transmission on the S-link and DL transmission on the P-link may be performed together when the S-link is idle. Furthermore, separate DL transmission on the S-link may not be allowed to avoid the situation where UL transmission on the P-link and DL transmission on the S-link occur simultaneously.

Fig. 11 illustrates anexemplary scenario 1100 according to an embodiment of the invention. Inscenario 1100, a multi-link AP (e.g., AP 120) may start DL transmission on the S-link and start DL transmission on the P-link together. For example, as shown in each of parts (a) and (B) of fig. 11, when the carrier sensing mechanism of the AP120 indicates that the medium is idle on the S-link, the AP120 may start DL transmission on the S-link and DL transmission on the P-link together, such as during PIFS before DL transmission on the P-link begins or the EDCA backoff count reaches 0.

Fig. 12 illustrates anexemplary scenario 1200 according to an embodiment of the invention. Inscenario 1200, the P-link may contend with EDCA fallback procedures by the multi-link AP120 and non-AP STAs (e.g., including STA 110). The AP120 may obtain the TXOP on the P-link with an EDCA fallback procedure. For example, when the back-off timer count falls to 0, the AP120 may start DL transmission on the P-link. When AP120 detects that the medium is idle, such as PIFS is idle on the S-link before DL transmission begins on the P-link (e.g., NAV 0 and/or CCA idle based on PIFS power detection (ED)), AP120 may begin DL transmission on the S-link and DL transmission on the P-link simultaneously. Transmissions and receptions on both links within a TXOP may be synchronized by the control of theAP 120.

Fig. 13 shows anexemplary scenario 1300 according to an embodiment of the present invention.Scenario 1300 is similar toscenario 1200, except that DL transmissions on both the P-link and S-link may include DL data and/or trigger frames to trigger UL transmissions.

Under the proposed scheme in accordance with the present invention, for rules regarding channel access for secondary links, in response to one or more of certain conditions being met, when there is no synchronized DL transmission on the P-link for a period of time, the multi-link AP120 may perform an EDCA fallback procedure to contend for the medium for triggering UL transmission on the S-link (but not on the P-link). Such conditions may include, by way of example and not limitation, (a) when there is no ongoing Downlink (DL) transmission on the P-link; (b) when relevant non-AP STAs (e.g., STA110 and STA 115) obtain a TXOP on the P-link; (c) when the basic NAV of AP120 on the P-link is set (as defined by the current IEEE standard, the timer is set by an Overlapping Basic Service Set (OBSS) TXOP, meaning there is an ongoing DL transmission on the P-link from other BSSs); and (d) when the AP120 indicates no DL transmission on the P-link for a period of time (e.g., the AP120 itself will not perform DL transmission). Under the proposed scheme, when AP120 indicates no DL transmission on the P-link for a period of time, each STA110 andSTA 115 may perform an EDCA backoff procedure to contend for the medium for UL transmission on the S-link.

FIG. 14 shows anexample scenario 1400 according to an embodiment of the invention. Inscenario 1400, the P-link may be contended by AP120 and non-AP STAs (e.g., STA110 and/or STA 115) with an EDCA backoff procedure. When the AP120 detects a UL transmission on the P-link targeted for the AP120, the AP120 may contend for the medium on the S-link with an EDCA backoff procedure. When its back-off timer count falls to 0, the AP120 may send a trigger frame (labeled "TF" in fig. 14) on the S-link. UL trigger based transmission on the S-link (labeled "TUL" in fig. 14) may be limited to ending at the same time as TUL on the P-link. When a TXOP holder (e.g., a non-AP STA) supports trigger-based UL transmissions on the P-link, transmissions and receptions on the P-link and the S-link within the TXOP may be synchronized by the control of theAP 120. The duration of a TXOP on the S-link may be less than or equal to the duration of a TXOP on the P-link.

Fig. 15 shows anexemplary scenario 1500 according to an embodiment of the invention.Scenario 1500 is similar toscenario 1400 except that the TXOP holder (e.g., non-AP STAs) on the P-link is a legacy STA that does not support trigger-based UL transmissions. Inscenario 1500, AP120 may trigger UL transmission on the S-link when its back-off timer count falls to 0 on the S-link. In addition, the period of TXOP on the S-link may be less than or equal to the period of TXOP on the P-link.

Fig. 16 shows anexemplary scenario 1600 according to an embodiment of the invention. Inscenario 1600, AP120 may detect that the channel is busy on the P-link due to OBSS (e.g., basic NAV > 0). The timer at AP120 for EDCA backoff may drop to 0 on the S-link and then AP120 may transmit an UL trigger frame to trigger UL transmissions from STAs (e.g., STA110 or STA 115). The timers for EDCA backoff at the non-AP STAs (e.g., STA110 and STA 115) may drop on the P-link and then the non-AP STA may transmit an UL transmission targeted atAP 120. The TXOP on the S-link for UL trigger based transmission (labeled "TUL" in fig. 16) may be limited to the OBSS NAV on the P-link. TXOP on both P-link and S-link may be used for UL transmission.

Fig. 17 shows anexemplary scenario 1700 according to an embodiment of the invention. Inscenario 1700, the P-link may be contended by the AP120 and non-AP STAs (e.g., STA110 and STA 115) with an EDCA backoff procedure. When the AP120 indicates no DL transmission on the P-link for a period of time (e.g., a Target Wake Time (TWT), a beacon interval, a Delivery Traffic Indication Map (DTIM) interval, etc.), the AP may use EDCA on the S-link to contend for the medium on the S-link for the indicated period of time to trigger UL transmission. When the AP120 on the S-link drops its back-off timer to 0, the AP120 may initiate the TXOP and transmit the UL trigger on the S-link. The non-AP STA may obtain another TXOP on the P-link for UL transmissions. The two TXOPs may be independent of each other.

Fig. 18 shows anexemplary scenario 1800 according to an embodiment of the invention. Inscenario 1800, the P-link may be contended by the AP120 and non-AP STAs (e.g., STA110 and STA 115) with an EDCA backoff procedure. When the AP120 indicates no DL transmission on the P-link for a period of time (e.g., TWT, beacon interval, DTIM interval, etc.), the non-AP STAs may use EDCA to contend for the medium for UL transmission on the S-link for the indicated period of time. When a non-AP STA (e.g., STA110 or STA 115) drops its back-off timer to 0 on the S-link, the non-AP STA may initiate a TXOP and start an UL transmission on the S-link. Another TXOP on the P-link may be obtained by the same or a different non-AP STA for UL transmissions. The two TXOPs may be independent of each other.

Under the proposed scheme for requesting UL TXOP according to the present invention, a multi-link device (e.g., AP 120) may set a link pair and by sending a request frame using EDCA, the multi-link device may require a non-AP STA to request UL TXOP (e.g., request grant) on each link of the link pair. In response to a request frame on the link, a multi-link AP120 receiving a request frame on one link may transmit a response frame. For example, AP120 may transmit a response frame upon receiving a request frame when there is no TXOP of an ongoing DL data transmission on the other link of the link pair. Under the proposed scheme, the AP120 may trigger UL transmission on the other link of the pair. Further, during the request frame request, the AP120 may not contend for DL transmission on the other link of the link pair. Further, on each link of the link pair, the AP120 may contend for the medium independently using EDCA. Some examples of requested contention-based channel access for UL transmissions are shown in fig. 19-21.

Fig. 19 shows anexemplary scenario 1900 in accordance with the present invention. Inscenario 1900, a multi-link device (e.g., AP 120) may set up two links (e.g., link 1 and link 2) in the 6GHz band. The AP120 may not support simultaneous transmission on one link and reception on another link. On each link, AP 210 indicates that non-AP STAs (e.g., STA110 and STA 115) will use EDCA to send a request frame to request the TXOP for UL transmissions. For example, the AP120 may set a Request To Send (RTS) threshold of 0 or a smaller value based on the TXOP such that non-AP STAs may always transmit an RTS frame to obtain the TXOP for UL data transmission. A non-AP STA (e.g., STA110 or STA 115) may use the EDCA contention medium onlink 2 to send a request frame (e.g., RTS) and wait for a response frame (e.g., Clear To Send (CTS)). However, in this example, the AP120 may not respond to the request frame onlink 2 because there is an ongoing DL TXOP onlink 1.

Fig. 20 shows anexemplary scenario 2000 according to an embodiment of the invention. Inscenario 2000, a multi-link device (e.g., AP 120) may set up two links (e.g., link 1 and link 2) in the 6GHz band. AP120 may not support simultaneous transmission on one link and reception on another link. On each link, AP120 may indicate that non-AP STAs (e.g., STA110 and STA 115) are to use EDCA generation request frames to request TXOPs for UL transmissions. For example, the AP120 may set the TXOP-based RTS threshold to a value of 0 or less such that non-AP STAs will always transmit an RTS frame to obtain a TXOP for UL data transmission. A non-AP STA on link 2 (e.g., STA110 or STA 115) may transmit a request frame (e.g., RTS) using the EDCA contention medium and wait for a response frame (e.g., CTS). A non-AP STA onlink 2 may receive the CTS frame and obtain the TXOP for transmitting UL data. The AP may use EDCA onlink 1 to trigger UL transmissions.

Fig. 21 shows anexemplary scenario 2100 according to an embodiment of the invention. Inscenario 2100, a multi-link device (e.g., AP 120) may set up two links (e.g., link 1 and link 2) in the 6GHz band. AP120 may not support simultaneous transmission on one link and reception on another link. On each link, the AP120 may indicate that non-AP STAs are to use EDCA transmit request frames to request TXOPs for UL transmissions. For example, AP120 may set the RTS threshold based on the TXOP to 0 or a smaller value such that non-AP STAs (e.g., STA110 and STA 115) always transmit an RTS frame to obtain the TXOP for UL data transmission. non-AP STAs (e.g., STA110 and STA 115) may use the EDCA contention medium onlink 2 to send request frames (e.g., RTS) and wait for response frames (e.g., CTS). Because there is no ongoing DL TXOP onlink 1, the AP120 may respond to the request frame onlink 2. In the example shown in fig. 21, AP120 may not start DL transmission onlink 1 during the TXOP obtained by STA1 onlink 2. For example, the AP120 may defer any ongoing backoff procedures onlink 1 for DL transmissions until the end of the TXOP period onlink 2. Alternatively, there may be internal collisions until the end of the TXOP period onlink 2.

Fig. 22 illustrates anexemplary system 2200 having at least one exemplary apparatus 2210 and an exemplary apparatus 2220 according to an embodiment of the invention. Each device 2210 and device 2220 may perform various functions to implement the schemes, techniques, processes, and methods described herein for EHT multilink access and operation in wireless communications, including the various schemes described above for the various proposed designs, concepts, schemes, systems, and methods and the processes described below. For example, apparatus 2210 may be implemented in STA110 orSTA 115 and apparatus 2220 may be implemented in AP120, or vice versa.

Each device 2210 and 2220 may be part of an electronic device, which may be a STA or AP, such as a portable or mobile device, a wearable device, a wireless communication device, or a computing device. When implemented in a STA, each of the device 2210 and the device 2220 may be implemented in a smart phone, a smart watch, a personal digital assistant, a digital camera, or a computing device, such as a tablet, a desktop, or a laptop. Each device 2210 and device 2220 can also be part of a machine type device, which can be an IoT device, such as a stationary or fixed device, a home device, a wireless communication device, or a computing device. For example, each device 2210 and 2220 may be implemented in an intelligent thermostat, an intelligent refrigerator, an intelligent door lock, a wireless speaker, or a home control center. When implemented or implemented as a network device, the device 2210 and/or the device 2220 can be implemented in a network node, such as an AP in a WLAN.

In some embodiments, each of the device 2210 and the device 2220 may be implemented in the form of one or more Integrated Circuit (IC) chips, such as, but not limited to, one or more single-core processors, one or more multi-core processors, one or more Reduced Instruction Set Computing (RISC) processors, or one or more Complex Instruction Set Computing (CISC) processors. In various aspects described above, each of the apparatus 2210 and the apparatus 2220 may be implemented at or as a STA or an AP. Each of the device 2210 and the device 2220 may include at least some of the elements shown in fig. 22, e.g., a processor 2212 and a processor 2222, respectively. Each of the device 2210 and the device 2220 may further include one or more other elements (e.g., an internal power source, a display device, and/or a user interface device) not suggested in connection with the present invention, and, thus, for the sake of brevity, such devices of the device 2210 and the device 2220 are not shown in fig. 22 and will not be described further below.

In an aspect, each of processor 2212 and processor 2222 may be implemented in the form of one or more single-core processors, one or more multi-core processors, one or more ric processors, or one or more CISC processors. That is, even though the term "processor" may be used herein to refer to both the processor 2212 and the processor 2222, each of the processor 2212 and the processor 2222 may include multiple processors in some embodiments and a single processor in some other embodiments, in accordance with the present invention. On the other hand, each of the processor 2212 and the processor 2222 may be implemented in hardware (e.g., optionally, firmware) with electronic components such as, but not limited to, one or more transistors, one or more diodes, one or more capacitors, one or more resistors, one or more inductors, one or more memristors, and/or one or more varactors configured and used to achieve particular objectives according to the present disclosure. In other words, in at least some embodiments, each of processor 2212 and processor 2222 is a specially designed, configured, and configured special purpose machine for performing specific tasks, including with respect to EHT multilink access and operation in wireless communications according to embodiments of the present invention.

In some embodiments, the apparatus 2210 may further include atransceiver 2216 coupled to the processor 2212. Thetransceiver 2216 may include a transmitter capable of wirelessly transmitting data and a receiver capable of wirelessly receiving data. In some embodiments, the device 2220 may also include a transceiver 2226 coupled to the processor 2222. The transceiver 2226 may include a transmitter capable of wirelessly transmitting data and a receiver capable of wirelessly receiving data.

In some embodiments, the apparatus 2210 may further include amemory 2214 coupled to the processor 2212 and capable of being accessed by the processor 2212 and storing data therein. In some embodiments, the device 2220 may further include a memory 2224 coupled to the processor 2222 and capable of being accessed by the processor 2222 and storing data therein. Each ofmemory 2214 and memory 2224 may include one type of Random Access Memory (RAM), such as dynamic RAM (dram), static RAM (sram), transistor RAM (T-RAM), and/or 0-capacitor RAM (Z-RAM). Alternatively, each ofmemory 2214 and memory 2224 may include a type of Read Only Memory (ROM), such as a mask ROM, a Programmable ROM (PROM), an Erasable Programmable ROM (EPROM), and/or an Electrically Erasable Programmable ROM (EEPROM). Alternatively, or in addition, each of memory 214 and memory 2224 may include a type of non-volatile random access memory (NVRAM) such as flash memory, solid-state memory, ferroelectric ram (feram), magnetoresistive ram (mram), and/or phase change memory.

Each of the device 2210 and the device 2220 may be communication entities capable of communicating with each other using the scheme proposed according to the present invention. For purposes of illustration, and not limitation, the following provides a description of the performance of device 2210 (e.g., a STA) and device 2220 (e.g., an AP). It is noted that although the described exemplary embodiments are provided in the context of a WLAN, the same may apply to other types of networks as well.

Under the proposed scheme for EHT multilink channel access in accordance with the present invention, wherein the device 2210 is implemented or embodied as a STA110 and the device 2220 is implemented or embodied as an AP120 associated with a BSS (e.g., BSS 130) of a wireless network (e.g., a WLAN in a network environment in accordance with one or more IEEE 802.11 standards), the processor 2222 of the device 2220 may establish a plurality of links including a primary link and at least one secondary link via the transceiver 2226. Further, the processor 2222 may transmit a management frame (e.g., a beacon) on the primary link via the transceiver 2226 to indicate the multi-link performance of the device 2220. Further, processor 2222 may configure the secondary link for one or more non-AP STAs (e.g., for device 2210 of STA 110) capable of operating on the primary link as well as the secondary link via the transceiver 2226 through the multilink performance and operating parameters of the associated process on the primary link. In some embodiments, the processor 2222 may establish the primary link and the secondary link when the device 2220 is unable to support transmission and reception that are synchronized on the primary link and the secondary link. In some embodiments, the processor 2222 may allow another one or more non-AP STAs (e.g., legacy STAs) that are not capable of multi-link operation to associate on the primary link but not on the secondary link.

In some embodiments, processor 2222 may configure the secondary link to be enabled for trigger-based uplink channel access and disabled for contention-based uplink channel access. In this case, the processor 2222 may configure the secondary link when the device 2220 is unable to support simultaneous transmissions and receptions over the primary link and the secondary link.

In some embodiments, a TXOP initiated on a primary link (e.g., triggering a TXOP) may trigger another TXOP (triggered TXOP) on a secondary link. In some embodiments, triggering a TXOP and the triggered TXOP may be synchronized. For example, the end point of the triggered TXOP on the secondary link may be the same or earlier than the end point of the triggered TXOP on the primary link. In some embodiments, the start and end points of PPDUs on the primary and secondary links may be aligned with the period of the triggered TXOP.

In some embodiments, the processor 2222 may perform additional operations. For example, the processor 2222 may trigger the associated one or more STAs via the transceiver 2226 to perform UL transmission on the secondary link by at least one of: (a) contend for the medium directly on the secondary link for transmission of the UL trigger frame; (b) initiated by one of the one or more STAs via a trigger request indication (e.g., a reverse exchange indication) in an ongoing PPDU on the primary link; (c) a multi-link acknowledgement with trigger information on the primary link or on both the primary and secondary links.

In some embodiments, the processor 2222 may perform additional operations. For example, the processor 2222 may receive a first PPDU from a device 2210 (e.g., a first STA (e.g., STA 110) of the one or more STAs) on a primary link via the transceiver 2226, wherein the first PPDU includes a request to trigger UL transmission on the secondary link. Further, in response to receiving the first PPDU, processor 2222 may transmit a control frame (e.g., a ML-BA) with trigger information over a primary link and a secondary link via transceiver 2226, requesting synchronized UL transmissions over the primary link and the secondary link. Further, in response to transmitting the control frame, the processor 2222 may receive a plurality of additional PPDUs from the apparatus 2210 or from the apparatus 2210 and at least one second STA of the associated one or more STAs on the primary link as well as the secondary link via the transceiver 2226. Further, in response to receiving the plurality of additional PPDUs, processor 2222 may transmit via transceiver 2226 a plurality of BAs in synchronization on the primary link and the secondary link, each BA for a respective PPDU of the plurality of additional PPDUs.

In some embodiments, the processor 2222 may perform additional operations. For example, processor 2222 may transmit a multi-link UL trigger on the primary link via transceiver 2226, wherein the multi-link UL trigger comprises a link ID bitmap indicating that at least one link of the plurality of links is triggered. Further, the processor 2222 may receive one or more PPDUs from the associated one or more STAs on the triggered at least one link via the transceiver 2226.

In some embodiments, the processor 2222 may perform additional operations. For example, the processor 2222 may configure the primary link and the secondary link via the transceiver 2226 such that: (a) at least one of the one or more STAs and the one or more other APs contend on the primary link by the EDCA channel contention for being allowed for DL and UL transmissions; and (b) at least one of the one or more STAs and one or more other APs contend on the secondary link by the EDCA channel contention is allowed for the device 2220 to trigger UL transmissions, except that the device 2220 indicates as an AP. For example, the device 2220 may indicate that no DL transmission is allowed on the primary link for a period of time. In this case, EDCA channel contention by one or more STAs on the secondary link may be allowed. Further, processor 2222 can perform an EDCA fallback procedure via transceiver 2226 to contend for the medium on the secondary link to trigger UL transmission when there is no synchronized DL transmission on the primary link for a period of time. Further, processor 2222 may trigger UL transmissions on the secondary link via transceiver 2226.

In some embodiments, the processor 2222 may also configure the primary link as well as the secondary link such that DL transmissions contended by the EDCA channel on the secondary link are only allowed together with DL transmissions on the primary link.

In some embodiments, the processor 2222 may perform additional operations. For example, the processor 2222 may instruct, via the transceiver 2226, one or more STAs on each of a first link and a second link (e.g., a primary link and one secondary link) of the multiple links to request an UL TXOP using EDCA. Further, in response to the indication, processor 2222 may receive a request frame on the second link from a first STA (e.g., device 2210 as STA 110) of the one or more STAs via transceiver 2226. Further, when there is no ongoing DL TXOP on the first link, processor 2222 may transmit a response frame to the first STA via transceiver 2226, resulting in the first STA obtaining an UL TXOP on the second link. Further, the processor 2222 may perform one of the following: (1) trigger UL transmissions on the first link using EDCA, and (2) suppress DL transmissions on the first link during an UL TXOP on the second link obtained by the first STA.

Under the proposed scheme with respect to EHT multilink channel access and operation in accordance with an embodiment of the invention, device 2210 is implemented or embodied as STA110 and device 2220 is implemented or embodied as AP120 associated with a BSS (e.g., BSS 130) of a wireless network (e.g., a WLAN innetwork environment 100 according to one or more IEEE 802.11 standards), processor 2212 of device 2210 may receive via transceiver 2216 a management frame (e.g., a beacon) from device 2220 (as an AP, such as AP 120) on a primary link of a plurality of links, including the primary link and at least one secondary link, the management frame indicating the multilink performance of device 2220 (and on which device 2210 is capable of operating). Further, the processor 2212 may perform association processes on the primary link via thetransceiver 2216. Further, the processor 2212 may receive configuration from the device 2220 over the primary link via thetransceiver 2216, which configures the secondary link. Further, processor 2212 may perform one or more UL transmissions viatransceiver 2216 by: (i) contending for the medium on the primary link; (ii) each or both of the primary link and the secondary link are monitored for triggers.

In some embodiments, the processor 2212 may perform additional operations. For example, when the apparatus 2210 is not capable of multi-link operation, the processor 2212 may perform association over a primary link but not a secondary link via thetransceiver 2216. Further, processor 2212 may perform one or more UL transmissions viatransceiver 2216 by one or both of (i) contending for the medium on the primary link; (ii) the primary link is monitored for triggers.

In some embodiments, an ongoing TXOP (e.g., a triggered TXOP) of an intra-frame BSS frame exchange on a primary link may trigger another TXOP (e.g., a triggered TXOP) on a secondary link. In some embodiments, triggering a TXOP and the triggered TXOP may be synchronized. In some embodiments, the end point of the triggered TXOP on the secondary link may be the same or earlier than the end point of the triggered TXOP on the primary link.

In some embodiments, when the apparatus 2210 initiates an ongoing TXOP, the apparatus 2210 may indicate to the apparatus 2220 that the apparatus 2220 is granted permission to trigger the apparatus 2210 or related other STAs to perform UL transmissions on each or both of the primary link and the secondary link. Further, the device 2220 may respond to the device 2210 with acknowledgement and trigger information to trigger one or more STAs associated with the device 2220 to perform UL transmissions on each or both of the primary link and the secondary link.

In some embodiments, trigger information may be transmitted on each or both of the primary link and the secondary link. In some embodiments, the trigger information may indicate at least one of: (a) a link ID bitmap instructing at least one of the one or more STAs to monitor for a trigger on at least one of the plurality of links that is triggered; (b) a target time for at least one STA of the one or more STAs to receive a trigger; and (c) resource scheduling information or transmission parameters or both.

In some embodiments, when the device 2220 initiates an ongoing TXOP, the device 2220 may trigger one or more related STAs to perform UL transmissions on each or both of the primary link and the secondary link. Further, the device 2220 may be triggered by transmitting trigger information on the primary link.

In some embodiments, in response to receiving the trigger information from the apparatus 2220, the apparatus 2210 may respond to the trigger-based PPDU and request another trigger for use on the primary link and the secondary link.

In some embodiments, the processor 2212 may perform additional operations. For example, the processor 2212 may transmit a request to the device 2220 via the transceiver on the primary link, the request being triggered for UL transmission on the secondary link. Further, in response to transmitting the request, the processor 2212 may receive a trigger frame addressed to the apparatus 2210 over the secondary link via thetransceiver 2216. Further, in response to receiving the trigger frame, the processor 2212 may perform CCA on the secondary link via thetransceiver 2216. Further, processor 2212 may refrain from UL transmission on the secondary link until a frame is detected by apparatus 2210 that may set a NAV or until a period of time equal to a predetermined delay has elapsed, whichever is earlier.

In some embodiments, the processor 2212 may perform additional operations. For example, processor 2212 may transmit a first PPDU viatransceiver 2216, where the first PPDU includes a request for device 2220 to trigger a UL transmission on the secondary link. Further, in response to transmitting the first PPDU, processor 2212 may receive control frames (e.g., BL-BA) over the primary link and the secondary link viatransceiver 2216 to request synchronized UL transmissions over the primary link and the secondary link. Further, in response to receiving the control frame, processor 2212 may transmit one or more additional PPDUs over the primary link and the secondary link viatransceiver 2216. Further, in response to transmitting the one or more additional PPDUs, processor 2212 may receive, viatransceiver 2216, a plurality of BAs on the primary link as well as the secondary link, each BA for a respective PPDU of the one or more additional PPDUs.

In some embodiments, the processor 2212 may perform additional operations. For example, processor 2212 may receive a plurality of link UL transmissions on a primary link viatransceiver 2216, where the plurality of link UL triggers include a link ID bitmap indicating that at least one of the plurality of links is triggered. Further, the processor 2212 may transmit one or more PPDUs over the triggered at least one link via thetransceiver 2216.

In some embodiments, the processor 2212 may perform additional operations. For example, processor 2212 may receive configuration from the AP (e.g., device 2220 as AP 120) viatransceiver 2216, configure the primary link and the secondary link such that: (a) the one or more STAs contend by the EDCA channel contention on the primary link for being allowed for DL and UL transmissions, and (b) the one or more STAs contend by the EDCA channel contention on the secondary link for being allowed for the AP to trigger UL transmissions, except that no DL transmissions are allowed on the primary link for a period of time as indicated by the AP, EDCA channel contention on the secondary link by the one or more STAs is allowed. Further, when the AP indicates no DL transmission on the secondary link for a period of time, the processor 2212 may perform an EDCA fallback procedure via thetransceiver 2216 to contend for the medium on the secondary link for UL transmission.

In some embodiments, processor 2212 may also receive configuration from the AP viatransceiver 2216, configuring the primary link as well as the secondary link such that DL transmissions contended by the EDCA channel on the secondary link are only allowed together with DL transmissions on the primary link.

In some embodiments, the processor 2212 may perform additional operations. For example, the processor 2212 may receive an indication from the AP on each of a first link and a second link of the multiple links via thetransceiver 2216 to request an UL TXOP using EDCA. Further, in response to receiving the indication, the processor 2212 may transmit a request frame over the second link via thetransceiver 2216. Further, when there is no ongoing DL TXOP on the first link, processor 2212 may receive a response frame from the AP viatransceiver 2216 to cause the STA to obtain an UL TXOP on the secondary link. Further, the processor 2212 via thetransceiver 2216 may perform one or both of the following: (i) perform UL transmission on the second link during the UL TXOP, and (ii) receive a trigger frame from the AP, triggering UL transmission on the first link.

Fig. 23 illustrates anexemplary process 2300, according to an embodiment of the invention.Process 2300 may represent an aspect that implements various proposed designs, concepts, schemes, systems and methods described above. More particularly,process 2300 may represent an aspect of the proposed concepts and schemes regarding EHT multilink channel access and operation in accordance with embodiments of the present invention.Process 2300 can include one or more operations, actions, or functions illustrated byblocks 2310, 2320, and 2330. Although shown as separate blocks, various blocks ofprocess 2300 may be split into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. Further, the blocks/sub-blocks ofprocess 2300 may be implemented in the order shown in fig. 23 or in a different order. Further, one or more blocks/sub-blocks ofprocess 2300 may be performed repeatedly or iteratively. Theprocess 2300 may be comprised of or implemented by the devices 2210 and 2220 as well as any variations thereof. For purposes of illustration only and not limitation,process 2300 is described in the context of device 2210 being implemented in or as STA110 and device 2220 being implemented in or as AP120 of a wireless network, such as a WLAN in anetwork environment 100 in accordance with one or more IEEE 802.11 standards.Process 2300 can begin atblock 2310.

At 2310,process 2300 can involve processor 2222 of device 2220 establishing a plurality of links including a primary link and at least one secondary link via transceiver 2226. From 2310,process 2300 can proceed to 2320.

At 2320,process 2300 can involve processor 2222 transmitting a management frame (e.g., a beacon) over the primary link via transceiver 2226 to indicate multi-link performance of device 2220. From 2320,process 2300 may proceed to 2330.

At 2330,process 2300 may involve processor 2222 configuring, via transceiver 2226, a secondary link with multi-link performance and operating parameters for one or more non-AP STAs (e.g., device 2210 as STA 110) capable of operating on the primary link as well as the secondary link through an associated process on the primary link.

In some embodiments,process 2300 can also involve processor 2222 establishing a primary link and a secondary link when device 2220 is unable to support simultaneous transmission and reception on the primary link and the secondary link.

In some embodiments,processor 2300 may also involve processor 2222 allowing another one or more non-AP STAs that are not capable of multi-link operation to associate on the primary link but not on the secondary link.

In some embodiments,process 2300 also involves processor 2222 configuring the secondary link to be enabled for trigger-based uplink channel access and disabled for contention-based uplink channel access. In this case,process 2300 can involve processor 2222 configuring the secondary link when device 2220 is unable to support simultaneous transmission and reception on the primary link and the secondary link.

In some embodiments, a TXOP initiated on a primary link (as a trigger TXOP) may trigger another TXOP (triggered TXOP) on a secondary link. In some embodiments, triggering a TXOP and the triggered TXOP may be synchronized. For example, the end point of the triggered TXOP on the secondary link is the same or earlier than the end point of the triggered TXOP on the primary link. In some embodiments, the start and end points of PPDUs on the primary and secondary links may be aligned with the period of the triggered TXOP.

In some embodiments,process 2300 may involve processor 2222 performing additional operations. For example,process 2300 may involve processor 2222 triggering, via transceiver 2226, the associated one or more STAs to perform UL transmissions on the secondary link by at least one of: (a) contend for the medium directly on the secondary link for transmission of the UL trigger frame; (b) initiated by one of the one or more STAs through a trigger request indication (reverse switching indication); and (c) a multi-link acknowledgement with trigger information on the primary link or on both the primary and secondary links.

In some embodiments,process 2300 may involve processor 2222 performing additional operations. For example,process 2300 may involve processor 2222 receiving a first PPDU from a device 2210 (a first STA that is one or more STAs, e.g., STA 110) on a primary link via transceiver 2226, wherein the first PPDU includes a request for the AP to trigger UL transmission on the second link. Further, in response to receiving the first PPDU,process 2300 may involve processor 2222 requesting synchronized UL transmissions on the primary link and the secondary link via transceiver 2226 for transmission of a control frame (e.g., a ML-BA) having trigger information on the primary link and the secondary link. Further, in response to transmitting the control frame,process 2300 may involve processor 2222 receiving, via transceiver 2226, a plurality of additional PPDUs from device 2210 or from device 2210 and at least one second STA of the associated one or more STAs on the primary and secondary links. Further, in response to receiving the plurality of additional PPDUs,process 2300 may involve processor 2222 transmitting, via transceiver 2226, a plurality of BAs on the primary link and the secondary link, each BA for a respective PPDU of the plurality of additional PPDUs.

In some embodiments,process 2300 may involve processor 2222 performing additional operations. For example,process 2300 can involve processor 2222 transmitting, via transceiver 2226, a multilink ML trigger over the primary link, wherein the multilink trigger comprises a link ID bitmap indicating that at least one link of the plurality of links is triggered. Further,process 2300 may involve processor 2222 receiving, via transceiver 22226, one or more PPDUs from an associated one or more STAs on the triggered at least one link.

In some embodiments,process 2300 may involve processor 2222 performing additional operations. For example,process 2300 may involve processor 2222 configuring, via transceiver 2226, a primary link and a secondary link such that (a) contention by EDCA channel contention on the primary link by at least one of the one or more STAs and one or more other APs is allowed for DL and UL transmissions, and (b) contention by EDCA channel contention on the secondary link by at least one of the one or more STAs and the one or more other APs is allowed for device 2220 to trigger UL transmissions, except as indicated by device 2220 as an AP. For example, the device 2220 may indicate that no DL transmission is allowed on the primary link for a period of time. Thus, EDCA channel contention by one or more STAs on the secondary link may be allowed. Further,process 2300 can involve processor 2222 executing an EDCA fallback process via transceiver 2226 to contend for a medium on a secondary link to trigger UL transmission when there is no DL transmission on the primary link for a period of time. Further,process 2300 can involve processor 2222 triggering UL transmissions on the secondary link via transceiver 2226.

In some embodiments,processor 2300 may be directed to processor 2222 to configure the primary link as well as the secondary link such that DL transmissions contended by the EDCA channel on the secondary link are only allowed along with DL transmissions on the primary link.

In some embodiments,process 2300 may involve processor 2222 performing additional operations. For example,process 2300 may involve processor instructing, via transceiver 2226, the one or more STAs on each of a first link and a second link (e.g., one of a primary link and a plurality of secondary links) of a plurality of links to request an UL TXOP using EDCA. Further, in response to the indication,process 2300 may involve processor 2222 receiving a request frame from a first STA of the one or more STAs (e.g., device 2210 as STA 110) on the second link via transceiver 2226. Further, in the absence of an ongoing DL TXOP on the first link,process 2300 may involve processor 2222 transmitting a response frame to the first STA via transceiver 2226 to cause the first STA to obtain an UL TXOP on the second link. Further,process 2300 can involve processor 2222 performing one of: (1) trigger UL transmissions on the one link using EDCA, and (2) refrain from DL transmissions on the first link during an UL TXOP on the second link obtained by the first STA.

Fig. 24 illustrates anexemplary process 2400 according to an embodiment of the invention.Process 2400 can represent an aspect of the above-described implementations of various proposed designs, concepts, schemes, systems and methods. More specifically,process 2400 may represent a proposed aspect of EHT multilink channel access and operation in wireless communications according to an embodiment of the present invention.Process 2400 can include one or more operations, actions, or functions illustrated by one or more ofblocks 2410, 2420, and 2430. Although shown as separate blocks, various blocks ofprocess 2400 may be broken down into additional blocks, combined into fewer blocks, or eliminated, depending on the desired implementation. Further, the blocks/sub-blocks ofprocess 2400 may be performed in the order shown in fig. 24 or in a different order. Further, one or more blocks/sub-blocks ofprocess 2400 can be repeatedly or iteratively performed. Theprocess 2400 can be comprised by or implemented in the device 2210 as well as the device 2220 as well as variations thereof. For purposes of illustration only and not limitation,process 2400 is described in the context of device 2210 being implemented in or as STA110 and device 2220 being implemented in or as AP120 of a wireless network (e.g., a WLAN innetwork environment 100 according to one or more IEEE 802.11 standards).Process 2400 may begin at block 2410.

At 2410,process 2400 may involve processor 2212 of device 2210 receiving, via transceiver 226, a management frame (e.g., a beacon) from device 2220 (as an AP (e.g., AP 120)) on a primary link of a plurality of links including the primary link and at least one secondary link, the management frame indicating multi-link performance of device 2220 (and device 2210 being capable of operating on the primary link as well as the secondary link). From 2410,process 2400 may proceed to 2420.

At 2420,process 2400 may involve processor 2212 performing an association process on the primary link viatransceiver 2216. From 2420,process 2400 may proceed to 2430.

At 2430,process 2400 can involve processor 2212 receiving a setup configuration to set up the secondary link from device 2220 over a primary link viatransceiver 2216.

In some embodiments,process 2400 may involve processor 2212 performing additional operations. For example, by performing operations,process 2400 may involve processor 2212 performing one or more UL transmissions viatransceiver 2216. In some embodiments,process 2400 may involve processor 2212 contending for the medium on a primary link. Further,process 2400 may involve processor 2212 monitoring each or both of the primary link and the secondary link for triggers.

In some embodiments,process 2400 may involve processor 2212 performing additional operations. For example, where apparatus 2210 is capable of multi-link operation,process 2400 may involve processor 2212 performing association over a primary link but not a secondary link viatransceiver 2216. Further,process 2400 can involve processor 2212 performing one or more UL transmissions viatransceiver 2216, by one or both of: (i) contend for the medium on the primary link, and (ii) monitor the primary link for a trigger.

In some embodiments, an ongoing TXOP (TXOP triggered) of an intra-frame BSS frame exchange on the primary link may trigger another TXOP (as a triggered TXOP) on the secondary link. In some embodiments, the triggered TXOP and the triggered TXOP are synchronized. In some embodiments, the end point of the triggered TXOP on the secondary link may be the same or earlier than the end point of the triggered TXOP on the primary link.

In some embodiments, upon initiation of an ongoing TXOP by the apparatus 2210, the apparatus 2210 may indicate a grant to the apparatus 2220 for the apparatus 2220 to trigger the apparatus 2210 or another related STA to perform UL transmissions on one or both of the primary link and the secondary link. Further, the means 2220 may respond to the means 2210 with acknowledgement and trigger information to trigger one or more STAs associated with the AP to perform UL transmissions on one or both of the primary link and the secondary link.

In some embodiments, the trigger information may be transmitted on one or both of the primary link and the secondary link. In some embodiments, the trigger information may indicate at least one of: (a) a link ID bitmap instructing at least one of the one or more STAs to monitor for a trigger on at least one of a plurality of links that is triggered; (b) a target time for at least one of the one or more STAs to receive a trigger; and (c) resource scheduling information or transmission parameters or both.

In some embodiments, upon initiation of an ongoing TXOP by the device 2220, the device 2220 may trigger one or more related STAs to perform UL transmissions on one or both of the primary link and the secondary link. Further, the means 2220 may trigger the one or more STAs by transmitting trigger information on the primary link.

In some embodiments, in response to receiving the trigger information from the apparatus 2220, the apparatus 2210 may respond to a trigger-based PPDU and a request for another trigger on the primary link and the secondary link.

In some embodiments,process 2400 may involve processor 2212 performing additional operations. For example,process 2400 can involve processor 2212 transmitting a request to device 2220 on a primary link viatransceiver 2216, the request being triggered for UL transmission on a secondary link. Further, in response to transmitting the request,process 2400 can involve processor 2212 receiving a trigger frame addressed to device 2210 over the secondary link viatransceiver 2216. Further, in response to receiving the trigger frame,process 2400 can involve the processor performing a CCA on the secondary link viatransceiver 2216. Further,process 2400 can involve processor 2212 refraining from UL transmission on the secondary link until device 2210 detects a frame that can set a NAV or until a period of time equal to a predetermined delay has elapsed, whichever is earlier.

In some embodiments,process 2400 may involve processor 2212 performing additional operations. For example,process 2400 may involve processor 2212 transmitting a first PPDU viatransceiver 2216, where the first PPDU includes a request for device 2220 to trigger a UL transmission on a secondary link. Further, in response to transmitting the first PPDU,process 2400 can involve processor 2212 receiving a control frame (e.g., ML-BA) over the primary link and the secondary link viatransceiver 2216 requesting UL transmissions synchronized over the primary link and the secondary link. Further, in response to receiving the control frame,process 2400 can involve processor 2212 transmitting one or more additional PPDUs over a primary link as well as a secondary link viatransceiver 2216. Further, in response to transmitting the one or more additional PPDUs,process 2400 may involve processor 2212 receiving, viatransceiver 2216, a plurality of BAs on a primary link and a secondary link, each BA for a respective PPDU of the one or more additional PPDUs.

In some embodiments,process 2400 may involve processor 2212 performing additional operations. For example,process 2400 can involve processor 2212 receiving a multi-link trigger on a primary link viatransceiver 2216, where the multi-link trigger contains a link ID bitmap indicating that at least one link of the plurality of links is triggered. Further,process 2400 can involve processor 2212 transmitting one or more PPDUs over the triggered at least one link viatransceiver 2216.

In some embodiments,process 2400 may involve processor 2212 performing additional operations. For example,process 2400 may involve processor 2212 receiving a configuration from an AP (e.g., device 2220 as AP 120) viatransceiver 2216, configuring a primary link and a secondary link such that: (a) contention by one or more STAs on the primary link through EDCA channel contention is allowed for DL as well as UL transmissions, and (b) contention by one or more STAs on the secondary link through EDCA channel contention is allowed for the AP to trigger UL transmissions, except in response to the AP indicating that no DL transmissions are allowed on the primary link for a period of time, EDCA channel contention by one or more STAs on the secondary link is allowed. Further, when the AP indicates no DL transmission on the primary link for a period of time,process 2400 may involve processor 2212 performing an EDCA fallback process viatransceiver 2216 to contend for the medium on the secondary link for UL transmission.

In some embodiments,process 2400 may also involve the processor receiving a configuration from the AP, configuring the primary link and the secondary link such that DL transmissions contended by the EDCA channel on the secondary link are only allowed along with DL transmissions on the primary link.

In some embodiments,process 2400 may also involve processor 2212 performing additional operations. For example,process 2400 may involve the processor receiving an indication on each of a first link and a second link of a plurality of links viatransceiver 2216 to request an UL TXOP using EDCA. Further, in response to receiving the indication,process 2400 can involve processor 2212 transmitting a request frame on a second link via the transceiver. Further, when there is no ongoing DL TXOP on the first link,process 2400 may involve processor 2212 receiving a response frame from the AP viatransceiver 2216, causing the STA to obtain the UL TXOP on the second link. Further, theprocess 2400 can involve the processor 2212 performing, via thetransceiver 2216, one or both of: (i) perform UL transmissions on the second link during an UL TXOP, and (ii) receive a trigger frame from the AP that triggered UL transmissions on the first link.

The subject matter described herein sometimes illustrates different components contained within, or connected with, other different components. It is to be understood that the architectures depicted are merely exemplary, and that in fact other architectures can be implemented which achieve the same functionality. Conceptually, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Hence, any two components herein combined to achieve a particular functionality can be seen as associated with each other such that the desired functionality is achieved, irrespective of architectures or intermedial components. Likewise, any two components so associated can be viewed as being "operably connected," or "operably coupled," to each other to achieve the desired functionality, and any two components capable of being so associated can also be viewed as being "operably couplable," to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components, and/or wirelessly interactable and/or wirelessly interacting components, and/or logically interacting and/or logically interactable components.

Furthermore, with respect to the use of substantially any plural and/or singular terms herein, those having ordinary skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. Various singular/plural permutations may be expressly set forth herein for the sake of clarity.

Furthermore, those of ordinary skill in the art will understand that, in general, terms used herein, and especially terms used in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms, e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc. It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, as an aid to understanding, the following appended claims may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an," the same applies to indefinite articles such as "at least one" or "one or more. Furthermore, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least one of the recited number, and the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations. Further, where a convention analogous to "at least one A, B and C, etc." is used, in general such a construction is intended that one of ordinary skill in the art will understand the convention such that "a system has at least one A, B and C" will include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B and C together, etc. In those instances where a convention analogous to "at least one A, B or C" is used, it is generally intended that such a construction will be understood by those of ordinary skill in the art that the convention such as "a system has at least one A, B or C" will include but not be limited to systems having a alone, B alone, C alone, a and B together, a and C together, B and C together, and/or A, B and C together, and the like. It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, in the description, claims, or drawings, will be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "a or B" will be understood to include the possibility of "a or B" or "a and B".

From the foregoing, it will be appreciated that various embodiments of the invention have been described herein for purposes of illustration, and that various modifications may be made without deviating from the scope and spirit of the invention. Accordingly, the various embodiments described herein are not intended to be limiting, with the true scope and spirit being indicated by the following claims.

Claims (30)

1. A method for multilink channel access, the method comprising:

establishing, by an apparatus implemented in an AP, a plurality of links, the plurality of links comprising a primary link and at least one secondary link;

transmitting, by the apparatus, a management frame on the primary link to indicate a multi-link performance of the AP; and

configuring, by the apparatus, the secondary link with multi-link performance and operating parameters for one or more non-AP STAs capable of operating on the primary link and the secondary link through an association process on the primary link.

2. The method for multilink channel access of claim 1, further comprising:

establishing, by the apparatus, the primary link and the secondary link if the AP cannot support simultaneous transmission and reception on the primary link and the secondary link.

3. The method for multilink channel access of claim 1, further comprising:

allowing, by the apparatus, another one or more non-AP STAs that are not multi-link capable of operation to associate on the primary link but not on the secondary link.

4. The method for multilink channel access of claim 1, further comprising:

configuring, by the apparatus, the secondary link to be enabled for trigger-based uplink channel access and disabled for contention-based uplink channel access.

5. The method for multilink channel access according to claim 4, wherein said configuring the secondary link to be enabled for trigger-based uplink channel access and disabled for contention-based uplink channel access comprises: configuring the secondary link if the AP cannot support simultaneous transmission and reception on the primary link and the secondary link.

6. The method for multilink channel access according to claim 1, wherein a transmission opportunity initiated on the primary link triggers another transmission opportunity on the secondary link, and wherein the transmission opportunity initiated on the primary link is synchronized with the another transmission opportunity on the secondary link.

7. The method for multilink channel access of claim 1, further comprising:

triggering, by the apparatus, the one or more non-AP STAs to perform uplink transmissions on the secondary link,

contend for a medium directly on the secondary link for transmission of an uplink trigger frame;

initiating, by one of the one or more non-AP STAs, a request-to-trigger uplink transmission through a trigger request indication in an ongoing PPDU on the primary link; and

a multi-link acknowledgement with trigger information on the primary link or on both the primary link and the secondary link.

8. The method for multilink channel access of claim 1, further comprising:

receiving, by the apparatus, a first PPDU from a first STA of the one or more non-AP STAs on the primary link, the first PPDU including a request to trigger an uplink transmission on the secondary link; and

transmitting, by the apparatus, a control frame with trigger information on the primary link and a secondary link requesting synchronized uplink transmissions on the primary link and the secondary link in response to receiving the first PPDU.

9. The method for multilink channel access of claim 8, further comprising:

receiving, by the apparatus, a plurality of additional PPDUs from the first STA or from the first STA and at least one second STA of the one or more non-AP STAs over the primary link and the secondary link in response to transmitting the control frame; and

transmitting, by the apparatus, a synchronized plurality of block acknowledgements over the primary link and the secondary link, each block acknowledgement for a respective PPDU of the plurality of additional PPDUs, in response to receiving the plurality of additional PPDUs.

10. The method for multilink channel access of claim 1, further comprising:

transmitting, by the apparatus, a multi-link uplink trigger on the primary link, the multi-link UL trigger including a link identifier bitmap indicating that at least one link of the plurality of links is triggered; and

receiving, by the apparatus, one or more PPDUs from the one or more non-AP STAs on the at least one triggered link.

11. The method for multilink channel access of claim 1, further comprising:

configuring, by the apparatus, the primary link and the secondary link such that:

contention on the primary link by an enhanced distributed channel access channel contention by at least one of the one or more STAs and one or more other APs is allowed for downlink transmissions and uplink transmissions; and

at least one of the one or more STAs and the one or more other APs is allowed to trigger uplink transmissions for the AP except as indicated by the AP on the secondary link by enhancing contention for a distributed channel access channel contention.

12. The method for multilink channel access of claim 11, further comprising:

performing, by the apparatus, an enhanced distributed channel access backoff procedure to contend for a medium on the secondary link to trigger an uplink transmission without a synchronized downlink transmission on the primary link for a period of time; and

triggering, by the apparatus, an uplink transmission on the secondary link.

13. The method for multilink channel access of claim 1, further comprising:

configuring, by the apparatus, the primary link and the secondary link such that downlink transmissions on the secondary link are only allowed together with downlink transmissions on the primary link through enhanced distributed channel access channel contention.

14. The method for multilink channel access of claim 1, further comprising:

instructing, by the device, the one or more STAs on each of a first link and a second link of the plurality of links to use an enhanced separate channel access request uplink transmission opportunity; and

in response to the indication, the apparatus receives a request frame from a first STA of the one or more non-AP STAs on the secondary link.

15. The method for multilink channel access of claim 14, further comprising:

transmitting, by the apparatus, a response frame to the first STA to cause the first STA to obtain the uplink transmission opportunity on the secondary link in the event that there is no ongoing downlink transmission opportunity on the first link; and

performing, by the device, one of:

performing a triggered uplink transmission on the first link; or

Refraining from transmitting downlink transmissions on the first link during the uplink transmission opportunity on the second link obtained by the first STA.

16. A method for multilink channel access, the method comprising:

receiving, by an apparatus implemented at a STA, a management frame from an AP on a primary link of a plurality of links, the plurality of links including the primary link and at least one secondary link, the management frame indicating multi-link performance of the AP;

performing, by the apparatus, an association process on the primary link; and

receiving, by the device operable on the primary link and the secondary link, a setup configuration from the AP on the primary link, setting up the secondary link.

17. The method for multilink channel access of claim 16, further comprising:

performing, by the apparatus, one or more uplink transmissions by:

by contending for the medium on the primary link; and

monitoring one or both of the primary link and the secondary link for triggering uplink transmissions.

18. The method for multilink channel access of claim 16, further comprising:

performing, by the device incapable of multi-link operation, an association process on the primary link and not on the secondary link; and

the apparatus performs one or more uplink transmissions by one or both of:

contending for a medium on the primary link and;

monitoring the primary link for triggering uplink transmissions.

19. The method for multilink channel access according to claim 16, wherein an ongoing transmission opportunity of an intra-base service set frame exchange on the primary link triggers another transmission opportunity on the secondary link, and wherein the ongoing transmission opportunity is synchronized with the another transmission opportunity on the secondary link.

20. The method for multilink channel access according to claim 19, wherein in the event that the ongoing transmission opportunity is initiated by the STA:

the STA indicating to the AP a grant for the AP to trigger the STA or another related STA to perform uplink transmissions on one or both of the primary link and the secondary link, and

the AP responding to the STAs with acknowledgement and trigger information to trigger one or more STAs associated with the AP to perform uplink transmissions on one or both of the primary link and the secondary link, wherein the trigger information is transmitted on one or both of the primary link and the secondary link, and wherein the trigger information indicates at least one of:

a link identifier bitmap indicating at least one of the one or more STAs to monitor for the trigger on at least one of the plurality of links that is triggered;

a target time for the at least one of the one or more STAs to receive the trigger; and

resource scheduling information or transmission parameters or both.

21. The method for multilink channel access according to claim 19, wherein in the event that the ongoing transmission opportunity is initiated by the AP:

the AP triggers the associated one or more STAs to perform uplink transmissions on one or both of the primary link and the secondary link.

22. The method for multilink channel access according to claim 21, wherein in response to receiving the trigger information from the AP, the STA responds to a trigger-based PPDU and requests another trigger for use on the primary link and the secondary link.

23. The method for multilink channel access of claim 16, further comprising:

transmitting, by the apparatus, a request to the AP on the primary link, the request being triggered for uplink transmission on the secondary link; and

receiving, by the device, a trigger frame addressed to the STA on the secondary link in response to transmitting the request.

24. The method for multilink channel access of claim 16, further comprising:

transmitting, by the apparatus, a first PPDU that includes a request for the AP to trigger an uplink transmission on the secondary link;

receiving, by the apparatus, a control frame on the primary link and on the secondary link in response to transmitting the first PPDU;

transmitting, by the apparatus, one or more additional PPDUs over the primary link and the secondary link in response to receiving the control frame; and

receiving, by the apparatus, a plurality of block acknowledgements over the primary link and the secondary link in response to transmitting the one or more additional PPDUs, each block acknowledgement for a respective PPDU of the one or more additional PPDUs.

25. The method for multilink channel access of claim 16, further comprising:

receiving, by the apparatus, a multi-link uplink trigger on the primary link, the multi-link uplink trigger comprising a link identifier bitmap indicating that at least one link of the plurality of links is triggered; and

transmitting, by the apparatus, one or more PPDUs on the at least one triggered link.

26. The method for multilink channel access of claim 16, further comprising:

receiving, by the apparatus, a configuration from the AP, the primary link and the secondary link being configured such that:

contention on the primary link by one or more STAs through enhanced distributed channel access channel contention is allowed for downlink and uplink transmissions, an

No downlink transmission is allowed on the primary link for a period of time as indicated by the AP, except for enhanced distributed channel access channel contention on the secondary link by the one or more STAs that is allowed for uplink transmission by the AP through enhanced distributed channel access channel contention on the secondary link.

27. The method for multilink channel access of claim 16, further comprising:

performing, by the apparatus, an enhanced distributed channel access backoff procedure to contend for a medium on the secondary link, if the AP indicates no downlink transmission on the primary link for a period of time.

28. The method for multilink channel access of claim 16, further comprising:

receiving, by the apparatus, a configuration from the AP, configuring the primary link and the secondary link such that downlink transmissions on the secondary link contended by an enhanced distributed channel access channel are only allowed with downlink transmissions on the primary link.

29. The method for multilink channel access of claim 16, further comprising:

receiving, by the apparatus, an indication from the AP on each of a first link and a second link of the plurality of links to use an enhanced distributed channel access request uplink transmission opportunity; and

transmitting, by the apparatus, a request frame on the second link in response to receiving the indication.

30. The method for multilink channel access of claim 29, further comprising:

receiving, by the apparatus, a response frame from the AP in the absence of an ongoing downlink transmission opportunity on the first link, resulting in the STA obtaining the uplink transmission opportunity on the secondary link; and

performing, by the apparatus, one or both of:

performing an uplink transmission on the second link during the uplink transmission opportunity; and

receiving a trigger frame from the AP triggering uplink transmission on the first link.

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