CN116582961A

CN116582961A - Wireless communication method and related device

Info

Publication number: CN116582961A
Application number: CN202310096344.6A
Authority: CN
Inventors: 石镕豪; 易志熹
Original assignee: MediaTek Singapore Pte Ltd
Current assignee: MediaTek Singapore Pte Ltd
Priority date: 2022-02-08
Filing date: 2023-02-07
Publication date: 2023-08-11

Abstract

The application provides a wireless communication method and a related device. The first multi-link device (MLD) determines that if/once a frame exchange of a first MLD with a second MLD on a second link of a plurality of enhanced multi-link single radio frequencies (EMLSRs) is to begin when a back-off timer associated with the second link expires or when a request frame associated with the second link is received, the frame exchange will overlap with reception of one or more frames from the second MLD to the first MLD on the first link of the plurality of EMLSRs. In response to the determination, the first MLD refrains from initiating a frame exchange on the second link upon expiration of a back-off timer associated with the second link in response to the back-off timer expiring or refrains from transmitting the requested frame on the second link in response to receiving the request frame.

Description

Wireless communication method and related device

Technical Field

The present application relates generally to wireless communications, and more particularly to an enhanced multi-link single-radio-frequency (EMLSR) channel access procedure (channel access procedure) in wireless communications.

Background

In a wireless local area network (wireless local area network, WLAN) according to the current institute of electrical and electronics engineers (Institute of Electrical and Electronics Engineer, IEEE) 802.11 specification, only one STA of a plurality of Stations (STAs) affiliated with a non-access point (non-AP) multi-link device (MLD) that is operating on one of one or more EMLSR links is capable of initiating a frame exchange with an Access Point (AP) MLD. However, after receiving a group-addressed medium access control (medium access control, MAC) protocol data unit (protocol data unit, MPDU), one or more other STAs attached to the non-AP MLD and not initiating the frame exchange may begin transmitting without performing a backoff procedure (backoff procedure). This may undesirably lead to collision. Accordingly, a solution for an EMLSR channel access procedure in wireless communications is needed.

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 a selection of concepts, benefits, and advantages of the novel and non-obvious techniques described herein. Selected implementations are described further below in the detailed description. Thus, the following summary is not intended to identify essential features of the claimed subject matter, nor is it intended to be used to identify the scope of the claimed subject matter.

It is an object of the present invention to provide schemes, concepts, designs, techniques, methods and apparatus related to EMLSR channel access procedures in wireless communications. The problems described herein may be solved under various proposals according to the present invention.

In a first aspect, the present invention provides a wireless communication method, comprising: the first multi-link device MLD determining that if a frame exchange of the first MLD with the second MLD on a second link of the plurality of enhanced multi-link single-radio EMLSR links is to begin when a back-off timer associated with the second link expires or when a request frame associated with the second link is received, the frame exchange will overlap with reception of one or more frames from the second MLD to the first MLD on a first link of the plurality of EMLSR links; and in response to the determination, the first MLD refrains from initiating the frame exchange on the second link upon expiration of the back-off timer in response to expiration of the back-off timer associated with the second link or refrains from transmitting the requested frame on the second link in response to receiving the request frame.

In some embodiments, avoiding initiating the frame exchange includes: the frame exchange is deferred until a time after the reception of the one or more frames on the first link ends.

In some embodiments, deferral of the frame exchange includes: performing a clear channel assessment, CCA, for the second link after the reception of the one or more frames on the first link is completed; invoking at least one backoff procedure on the second link when the CCA indicates that the second link is clear for transmission; and initiating the frame exchange on the second link upon expiration of the at least one backoff procedure.

In some embodiments, deferral of the frame exchange includes: the frame exchange is initiated after a clear channel assessment, CCA, on the second link and in a case where the CCA indicates that the second link is clear for transmission, wherein the CCA is performed after reception of the one or more frames on the first link is over.

In some embodiments, the receiving of the one or more frames comprises: one or more groups address the reception of media access control, MAC, protocol data unit MPDUs.

In some embodiments, the receiving of the one or more frames comprises: and receiving one or more beacon frames, wherein each beacon frame comprises a delivery service indication message (DTIM).

In some embodiments, the request frame includes: request to send an RTS frame or a trigger frame, and the requested frame includes: the CTS frame or the trigger-based TB physical layer protocol data unit PPDU is cleared.

In a second aspect, the present invention provides a wireless communication method, comprising: the first multi-link device MLD determining that if a frame exchange of the first MLD with the second MLD on a second link of the plurality of enhanced multi-link single-radio EMLSR links is to begin when a back-off timer associated with the second link expires, the frame exchange will overlap with reception of one or more frames from the second MLD to the first MLD on a first link of the plurality of EMLSR links; and, in response to the determination, the first MLD deferring the frame exchange to a time after receipt of the one or more frames on the first link ends.

In some embodiments, the frame exchange includes a transmission requesting to send an RTS frame.

In a third aspect, the present invention provides a wireless communication apparatus, implementable in a first multi-link device, MLD, the apparatus comprising a transceiver configured to wirelessly communicate with a second MLD, and a processor coupled to the transceiver and configured to: determining that if a frame exchange of the first MLD and the second MLD on a second link of the plurality of enhanced multi-link single-radio EMLSR links begins when a back-off timer associated with the second link expires or when a request frame associated with the second link is received, the frame exchange will overlap with reception of one or more frames from the second MLD to the first MLD on a first link of the plurality of EMLSR links; and in response to the determination, refraining from initiating the frame exchange on the second link upon expiration of the back-off timer in response to expiration of the back-off timer associated with the second link or refraining from transmitting the requested frame on the second link in response to receiving the request frame.

Notably, while the description provided herein is in the context of certain Radio access technologies, networks, and network topologies (e.g., wi-Fi), the proposed concepts, schemes, and any variants/derivatives thereof may be implemented in, for, or by other types of Radio access technologies, networks, and network topologies, such as, but not limited to, bluetooth, zigBee, fifth generation (5G)/New Radio (NR), long Term Evolution (LTE), LTE-Advanced (LTE-Advanced), LTE-Advanced Pro, internet of things (Internet-of-things (IoT), industrial Internet of things (IIoT), and narrowband Internet of things (NB-IoT). Accordingly, the scope of the invention is not limited to the examples described herein.

These and other objects of the present invention will be readily understood by those skilled in the art after reading the following detailed description of the preferred embodiments as illustrated in the accompanying drawings. The detailed description will be given in the following embodiments with reference to the accompanying drawings.

Drawings

The present invention will be more fully understood from the following detailed description and examples given with reference to the accompanying drawings.

FIG. 1 is a schematic diagram of an example network environment in which various solutions and schemes according to the invention may be implemented.

Fig. 2 is a schematic diagram of an example scenario according to an embodiment of the present invention.

Fig. 3 is a schematic diagram of an example scenario in accordance with an embodiment of the present invention.

Fig. 4 is a schematic diagram of an example scenario in accordance with an embodiment of the present invention.

Fig. 5 is a block diagram of an example communication system in accordance with an embodiment of the present invention.

Fig. 6 is a flow chart of an example method according to an embodiment of the invention.

Fig. 7 is a flow chart of an example method according to an embodiment of the invention.

In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the invention. It will be apparent, however, that one or more embodiments may be practiced without these specific details, and that different embodiments may be combined as desired and should not be limited to the embodiments set forth in the drawings.

Detailed Description

The following description is of preferred embodiments of the invention, which are intended to illustrate the technical features of the invention, but not to limit the scope of the invention. Certain terms are used throughout the description and claims to refer to particular elements, and it will be understood by those skilled in the art that manufacturers may refer to a like element by different names. Therefore, the present specification and claims do not take the difference in names as a way of distinguishing elements, but rather take the difference in functions of elements as a basis for distinction. The terms "element," "system," and "apparatus" as used in the present invention may be a computer-related entity, either hardware, software, or a combination of hardware and software. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to …". Furthermore, the term "coupled" means an indirect or direct electrical connection. Thus, if one device is coupled to another device, that device can be directly electrically connected to the other device or indirectly electrically connected to the other device through other devices or connection means.

Wherein corresponding numerals and symbols in the various drawings generally refer to corresponding parts, unless otherwise indicated. The drawings are clearly illustrative of relevant portions of the embodiments and are not necessarily drawn to scale.

The term "substantially" or "approximately" as used herein means that within an acceptable range, a person skilled in the art can solve the technical problem to be solved, substantially to achieve the technical effect to be achieved. For example, "substantially equal" refers to a manner in which a technician can accept a certain error from "exactly equal" without affecting the accuracy of the result.

SUMMARY

Embodiments in accordance with the present invention relate to various techniques, methods, schemes and/or solutions related to an EMLSR channel access procedure (channel access procedure) in wireless communications. According to the invention, a plurality of possible solutions can be implemented individually or in combination. That is, although the following describes the possible solutions separately, two or more of the possible solutions may be implemented in one combination or another.

FIG. 1 illustrates an example network environment 100 in which various solutions and techniques according to the present invention may be implemented. Fig. 2-7 illustrate example implementations of various proposed schemes in a network environment 100 according to the present invention. Referring to fig. 1 to 7, the present invention provides the following description of various proposed schemes.

Referring to fig. 1, a network environment 100 involves a first non-AP MLD (MLD 110) and a second non-AP MLD (MLD 120), which communicate wirelessly with the AP MLD (MLD 130) over a plurality of LINKs (e.g., labeled LINK1, LINK2, …, LINK N in the figures) according to one or more IEEE 802.11 standards. Each of MLD 110 and MLD120 may act as a non-AP MLD having multiple virtual (virtual) STAs attached thereto, and MLD 130 may act as an AP MLD having multiple virtual APs attached thereto. For purposes of illustration and not limiting the scope of the invention, in fig. 2-4, the MLD 110 is shown as being affiliated with a plurality of non-AP STAs (e.g., STA 11 and STA 12), and the MLD120 is shown as being affiliated with a plurality of non-AP STAs (e.g., STA 21 and STA 22). Accordingly, in fig. 2 to 4, the MLD 130 is shown as being affiliated with a plurality of AP STAs (e.g., AP 1 and AP 2). It is noted that while a certain number of STAs (e.g., two) are shown as being affiliated (also described as "affiliated") with each of the MLD 110, the MLD120, and the MLD 130, in practical implementations, the number of N STAs affiliated with each of the MLD 110, the MLD120, and the MLD 130 and the corresponding links therebetween may be the same or different, and are not limited to the number shown in the figures. Under various proposed schemes according to the present invention, the MLD 110, the MLD120, and the MLD 130 may be configured to perform an EMLSR channel access procedure (EMLSR channel access procedure) in wireless communication according to various proposed schemes described herein. It is noted that the various proposals may be implemented alone or, alternatively, in combination (e.g., two or more proposals are implemented together), although each of the various proposals is described below separately.

Under the current IEEE specifications, with respect to the EMLSR procedure, a non-AP MLD (e.g., each of MLD 110 and MLD 120) may operate in EMLSR mode on a specified set (specified set) of enabled (enabled) one or more links (one or more enabled links, which may also be described as "one or more enabled links") between the non-AP MLD and its associated AP MLD (e.g., MLD 130). The specified set of one or more enabled links (in which the EMLSR mode is applied) may be referred to as an EMLSR link (EMLSR links). An EMLSR link may be indicated in an enhanced multi-link (EML) link bitmap subfield of an EML Control field (Control field) of an enhanced EML operation mode notification frame (Operating Mode Notification frame) by setting a corresponding bit position (bit position) of the EMLSR link bitmap subfield (EMLSR Link Bitmap subfield) to 1. For EMLSR mode enabled in a single-radio-non-AP MLD (e.g., each of MLD 110 and MLD 120), if an STA affiliated (also may be described as "affiliated") with the non-AP MLD and operating on one of the EMLSR links is in a wake state, then one or more STAs affiliated with the non-AP MLD and operating on one of the EMLSR link bitmap subfield are in a sleep state (doze state) corresponding to a bit position or positions set to 0. In addition, the MLD of the dot11ehteml sroptioncompleted equal to 'true' may set the EML current capability subfield (EML Capabilities Present subfield) to 1, and may also set the EMLSR support subfield (EMLSR Support subfield) of the common information field (Common Info field) of the Basic Multi-Link element to 1 in all management frames (except authentication frames) including the Basic Multi-Link element. In one aspect, the MLD of the dot11EHTEMLM SROPTION implemented equal to 'false' and the dot11EHTEMLM MROPTION implemented equal to 'true' may set the EML current capability subfield to 1 and may also set the EMLSR support subfield of the EML capability subfield to 0. On the other hand, the MLD with dot11EHTEMLM SROPTION implemented equal to 'false' and dot11EHTEMLM OPTION implemented equal to 'false' may set the EML current capability subfield to 0.

Regarding the execution of the EMLSR procedure, when a non-AP MLD (e.g., each of MLD 110 and MLD 120) with dot11ehteml srop-implemented equal to 'true' wants/intends (ends to) to operate in an EMLSR mode on an EMLSR link, a STA attached to the non-AP MLD sends an EML operation mode notification frame to an AP attached to an AP MLD with dot11ehteml srop-implemented equal to 'true', wherein an EMLSR mode subfield (EMLSR Mode subfield) of an EML control field of the frame is set to 1. In addition, the AP attached to the AP MLD and receiving the EML operation mode notification frame from the STA attached to the non-AP MLD may transmit an EML operation mode notification frame as an acknowledgement (acknowledgement) of the EML operation mode notification frame transmitted by the STA attached to the non-AP MLD within a timeout interval (timeout interval) indicated in a transition timeout subfield (Transition Timeout subfield) in an EML capability subfield of a basic multi-link element and starting from a physical-layer protocol data unit (physical-layer protocol data unit, PPDU) transmitted by the AP attached to the AP MLD. The STA affiliated to the non-AP MLD operates in the EMLSR mode after successful transmission of the EML operation mode notification frame on one of the plurality of EMLSR links, and the STA on the other link of the EMLSR link may transition to the active mode (active mode) after a transition delay (transition delay) indicated in the transition timeout subfield of the EML capability subfield of the basic multi-link element, or, alternatively, immediately transition to the active mode after receiving the EML operation mode notification frame from one of the APs operating on the EMLSR link and affiliated to the AP MLD. In addition, the STA on one of the other links of the EMLSR link does not transmit a frame in which the power management subfield (Power Management subfield) is set to 1 until an EML operation mode notification frame is received from an AP affiliated with the AP MLD or until the timeout interval ends.

Regarding disable (disable) or present (execute) EMLSR procedures, when a non-AP MLD (e.g., each of MLD 110 and MLD 120) with dot11ehteml srop-implemented equal to 'true' intends to disable the EMLSR mode, an STA attached to the non-AP MLD may send an EML operation mode notification frame (with an EMLSR mode subfield of an EML control field of the frame set to 0) to an AP attached to an AP MLD (e.g., MLD 130) with dot11ehteml srop-implemented equal to 'true'. Accordingly, the AP attached to the AP MLD and receiving the EML operation mode notification frame from the STA attached to the non-AP MLD may transmit the EML operation mode notification frame to one of the plurality of STAs attached to the non-AP MLD as an acknowledgement of the EML operation mode notification frame transmitted by the STA attached to the non-AP MLD within a timeout interval indicated in a transition timeout subfield in an EML capability subfield of the basic multi-link element and started at the end of a PPDU transmitted by the AP attached to the AP MLD. After successful transmission of the EML operation mode notification frame sent by the STA affiliated with the non-AP MLD on one of the EMLSR links, the non-AP MLD may disable the EMLSR mode and the STA on the other link of the EMLSR link may transition to a power-save mode (power-save mode) immediately after a transition delay indicated in a transition timeout subfield in the EML capability subfield of the basic multi-link element or after receiving the EML operation mode notification frame from one of the plurality of APs affiliated with the AP MLD and operating on the EMLSR link. In addition, a STA on one of the other links of the EMLSR link does not transmit a frame with the power management subfield set to 0 until an EML operation mode notification frame is received from an AP affiliated with the AP MLD or until the timeout interval ends.

When the non-AP MLD (e.g., each of MLD 110 and MLD 120) operates in an EMLSR mode and the AP MLD (e.g., MLD 130) supports the EMLSR mode, certain circumstances may apply as described below. For example, by placing STA(s) (also referred to as "dependent STAs") corresponding to and attached to the EMLSR link in an awake state (awake state), the non-AP MLD may listen (listen) on the EMLSR link (EMLSR link), which may include a clear channel assessment (clear channel assessment, CCA) and receiving a frame-switched initial control frame (initial Control frame) initiated by the AP MLD. Furthermore, the frame-switched initial control frame may be a burst (e.g., a burst) of a multi-user request-to-RTS) or a buffer status poll (Buffer Status Report Poll, BSRP) using a rate of 6Mbps, 12Mbps or 24Mbps to copy PPDU format (duplicate PPDU forma) in orthogonal frequency division multiplexing (orthogonal frequency-division multiplexing, OFDM) or non-high-throughput (non-HT), the number of burst-to-RTS) trigger fields may be limited by the number of burst-buffer status trigger frames (e.g., a burst-to-RTS) in the BSRP field, which may be a burst-buffer status poll (e.g., a burst-to-RTS) of the multi-user request-transmission (multi-user request-to-RTS) and a Burst (BSRP) of the non-throughput (non-high-throughput) or non-throughput (non-HT) of PPDU) may be transmitted in the burst mode, the non-buffer status, the buffer status (tsw) of the buffer status (tsw) or buffer status) of the non-buffer status (tsw) link (tsw) at the buffer status), the buffer status (tsw) or buffer status (tsw) of the buffer status), and the buffer status (buffer status) may be limited, an AP affiliated with the AP MLD and initiating a frame exchange with the non-AP MLD on one of the multiple EMLSR links begins the frame exchange by sending an initial control frame to the non-AP MLD. Upon receiving an initial control frame of a frame exchange, STAs listening on the corresponding links affiliated with the non-AP MLD and on which the initial control frame was received may send or receive frames on the link on which the initial control frame was received, but not on the other EMLSR link(s) until the frame exchange is completed. A STA affiliated to a non-AP MLD can receive a PPDU after a short inter-frame space (SIFS) that begins at the end of its response frame transmission of an initial control frame request, according to its spatial stream capabilities, mode of operation, and link switching delays, wherein the PPDU is transmitted using multiple spatial streams on the link that received the initial control frame. During frame switching, other AP(s) affiliated with the AP MLD will not transmit frames to other STA(s) affiliated with the non-AP MLD over other EMLSR links of the plurality of EMLSR links.

If any particular condition described below is met, the non-AP MLD switches back (switch back to) listening operations on the plurality of EMLSR links after the time indicated in the EMLSR switch delay subfield of the EML capability subfield in the common information field of the basic multilink element, and this is defined as the end of frame switch. For example, a Medium Access Control (MAC) layer of a STA affiliated to a non-AP MLD and receiving an initial control frame does not receive a PHY-rxstart. Indication primitive (pritive) during a timeout interval (timeout interval) of asifstime+aslottime+arxphystartdelay, where the timeout interval starts when a PPDU transmitted from a STA affiliated to an AP MLD as a response to a frame recently received from the AP affiliated to the AP MLD ends, or alternatively, when the timeout interval starts when an PPDU including a frame for the STA and not requiring immediate acknowledgement is received from an AP affiliated to the AP MLD ends. Further, the MAC layer of the STA affiliated to the non-AP MLD and receiving the initial control frame receives the PHY-rxstart. Indication primitive during the time-out interval of asifstime+aslottime+arxphystartdelay (wherein the time-out interval starts when the PPDU transmitted from the STA of the non-AP MLD as a response to the frame recently received from the AP affiliated to the AP MLD ends or, alternatively, the time-out interval starts when the PPDU received from the AP affiliated to the AP MLD, which contains the frame for the STA and does not require immediate acknowledgement, ends), and the STA affiliated to the non-AP d does not detect any of the following frames within the PPDU corresponding to the PHY-rxstart. Indication: (a) A separately addressed frame (individually addressed frame) with RA equal to the MAC address of the STA attached to the non-AP MLD; (b) A trigger frame, one of the user information fields of which is addressed to a STA affiliated with the non-AP MLD; (c) CTS-to-self frame with RA equal to the MAC address of the AP attached to the AP MLD; (d) A Multi-STA (Multi-STA) block acknowledgement (Block Acknowledgement, blockAck) frame with one of its association identifier (Association Identifier, AID) traffic identifier (traffic identifier, TID) information field (Per Association Identifier (AID) Traffic Identifier (TID) Info fields) addressed to STAs other than AP MLD; and, (e) a neighbor discovery protocol (Neighbor Discovery Protocol, NDP) advertise a frame, one of the STA info fields of which is addressed to STAs affiliated with the non-AP MLD. Finally, STAs attached to the non-AP MLD and receiving the initial control frame do not respond to frames recently received from the AP attached to the AP MLD and requiring an immediate response after SIFS.

When a non-AP MLD (e.g., MLD 110) is operating in EMLSR mode and an AP MLD (e.g., MLD 130) supports EMLSR mode, there are other applicable scenarios as described below. For example, if (in case coat) an AP affiliated with an AP MLD wants (end to) to continue frame exchange with an STA affiliated with a non-AP MLD and no response frame is received from this STA for the most recently transmitted frame requiring an immediate response after SIFS, then before the transmission network allocation vector (transmission network allocation vector, TXNAV) timer expires, the AP affiliated with the AP MLD sends another initial control frame addressed to the STA affiliated with the non-AP MLD. When the STA of the non-AP MLD starts a transmission opportunity (transmission opportunity, TXOP), the non-AP MLD switches back to listening operation on the EMLSR link after the duration indicated in the EMLSR switch delay subfield after the end of the TXOP. In addition, only one STA among the STAs affiliated with the non-AP MLD and operating on one of the EMLSR links may initiate a frame exchange with the AP MLD.

Fig. 2 shows an exemplary scenario 200 of an EMLSR channel access procedure under the proposed solution according to the present invention. In scenario 200, STA 11 and STA 12 affiliated with MLD 110 (non-AP MLD) operate on link 1 and link 2 (where link 1 and link 2 are EMLSR links) and communicate with the corresponding AP affiliated with MLD 130. In addition, STAs 21 and 22 affiliated to the MLD 120 (non-AP MLD) also operate on links 1 and 2 and communicate with corresponding APs affiliated to the MLD 130 (AP MLD). According to the proposed scheme of the present invention, in case a backoff timer (backoff timer) attached to a STA of a non-AP MLD on one of the plurality of EMLSR links expires, if a frame exchange on the one EMLSR link will overlap in time with the reception of one or more group-addressed MPDUs in another one of the plurality of EMLSR links, the STA attached to the non-AP MLD does not initiate (initiate) a frame exchange with the AP MLD (e.g. by delaying/deferring transmission), e.g. the one or more group-addressed MPDUs comprise one or more beacon frames of one or more delivery traffic indication messages (delivery traffic indication message, DTIM).

Referring to fig. 2, when the backoff timer of STA 12 on link 2 expires (e.g., the backoff timer of STA 12 counts down to 0), a possible frame exchange (would-be frame exchange, also described as "potential frame exchange" or "pending frame exchange") between STA 12 and the corresponding AP (e.g., AP 2) attached to MLD 130 and on link 2 is deferred (beled), and is not initiated by STA 12. Theoretically, this can avoid collision (collision) during the period of time that the reception of the group-addressed (or groups) MPDU (e.g., one or more beacon frames with DTIM) from the respective AP (e.g., AP 1) attached to MLD 130 to STA 11 over link 1 overlaps with the potential frame exchange (would-be frame exchange) between STA 12 and AP 2. Likewise, when the back-off timer of STA 22 on link 2 expires (e.g., the back-off timer of STA 22 counts down to 0), a potential frame exchange between STA 22 and the corresponding AP (e.g., AP 2) affiliated with MLD 130 and on link 2 may be deferred (labeled "Defer Tx" in the figure) and not initiated by STA 22. In theory, this may avoid collisions during periods of time from the reception of one or more group addressed MPDUs (e.g., one or more beacon frames with DTIM), labeled "Rx DTIM" on link 1, from the corresponding AP (e.g., AP 1) affiliated with MLD 130 to STA 21, overlapping with the potential frame exchange between STA 22 and AP 2.

Fig. 3 shows an example scenario 300 of an EMLSR channel access procedure without implementing the proposed scheme according to the present invention. Scene 300 may be a hypothetical continuation of scene 200 (hypothetical continuation). In scenario 300, after receiving the group addressing MPDU(s), a collision may occur if STAs that are attached to the non-AP MLD and do not initiate a frame exchange begin frame transmission without performing another backoff procedure.

Referring to fig. 3, after receiving the group addressing MPDU(s), if each of the STA 12 and STA 22 (neither STA 12 nor STA 22 initiates a frame exchange with AP 2) does not perform another backoff procedure (although the transmission of STA 12 on link 2 and the transmission of STA 22 on link 2 (e.g., RTS frames) collide) starts simultaneously on link 2 after the CCA based on the duration of the arbitrated inter-frame space (arbitration inter-frame space, AIFS) determines that channel (or link 2) is idle). This is undesirable and should be avoided.

Fig. 4 shows an exemplary scenario 400 of an EMLSR channel access procedure according to the proposed solution of the present invention. In scenario 400, when the non-AP MLD switches back to listening operation on the EMLSR link (listening operation), the STA attached to the non-AP MLD invokes a new backoff procedure in the event that the value of the STA's backoff counter is 0 (e.g., has expired due to a previous countdown).

Referring to fig. 4, after the initial (initial) backoff process counts down to 0, each of MLD 110 and MLD 120 switches back to listening operation on link 2. Further, since the value of the back-off timer is 0, each of the STA 12 and the STA 22 invokes a new back-off procedure on the link 2 before performing any transmission on the link 2 (e.g., after detecting that the link 2 is idle through the CCA). In theory, this may avoid simultaneous transmissions of STA 12 and STA 22 on link 2, thereby avoiding collisions.

Illustrative embodiments

Fig. 5 illustrates an example system 500 having at least example apparatus 510 and example apparatus 520 according to an embodiment of the invention. Each of the apparatus 510 and the apparatus 520 may perform various functions to implement the schemes, techniques, procedures, and methods described herein in connection with an EMLSR channel access procedure in wireless communications, including the various schemes described above with respect to the various proposed designs, concepts, schemes, systems, and methods, and the procedures described below. For example, apparatus 510 may be an example implementation of MLD 110 or MLD 120, and apparatus 520 may be an example implementation of MLD 130.

Each of the devices 510 and 520 may be part of an electronic device such as, but not limited to: a portable or mobile device, a wearable device, a wireless communication device, or a computing device. For example, each of apparatus 510 and apparatus 520 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 computer, a laptop computer, or a notebook computer. Each of the devices 510 and 520 may also be part of a machine type device, which may be an internet of things (IoT) device, for example, a fixed or non-mobile device, a home device, a wired communication device, or a computing device. For example, each of the devices 510 and 520 may be implemented in a smart thermostat, a smart refrigerator, a smart door lock, a wireless speaker, or a home control center. When implemented in or as a network device, device 510 and/or device 520 may be implemented in a network node, e.g., an AP in a WLAN.

In some embodiments, each of the apparatus 510 and the apparatus 520 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. Each of the apparatus 510 and the apparatus 520 may include at least some of those components shown in fig. 5, e.g., the processor 512 and the processor 522, respectively. Each of the apparatus 510 and the apparatus 520 may also include one or more other components (e.g., an internal power source, a display device, and/or a user interface device) not related to the proposed solution of the present invention, and thus, for simplicity, none of these components of the apparatus 510 and the apparatus 520 are shown in fig. 5, nor described below.

In an aspect, each of processor 512 and processor 522 may be implemented in the form of one or more single-core processors, one or more multi-core processors, one or more RISC processors, or one or more CISC processors. That is, although the singular term "processor" is used herein to refer to processor 512 and processor 522, each of processor 512 and processor 522 may include multiple processors in some embodiments, and may include a single processor in other embodiments according to the invention. In another aspect, each of processor 512 and processor 522 may be implemented in hardware (and, optionally, firmware) having electronic components including, for example, 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 arranged in accordance with the present invention to achieve a particular purpose. In other words, in at least some embodiments, each of processor 512 and processor 522 is a special purpose machine specifically designed, arranged, and configured to perform specific tasks including those tasks related to EMLSR channel access procedures in wireless communications according to various embodiments of the invention.

In some implementations, the apparatus 510 may further include a transceiver 516 coupled to the processor 512. The transceiver 516 is capable of wirelessly transmitting and receiving data. In some implementations, the apparatus 520 may further include a transceiver 526 coupled to the processor 522. The transceiver 526 may include a transceiver capable of wirelessly transmitting and receiving data. The transceiver 516 of the apparatus 510 and the transceiver 526 of the apparatus 520 may communicate with each other over one or more of a plurality of links link 1-link N, where N is a positive integer greater than 1, e.g., a first link and a second link (n=2).

In some implementations, the apparatus 510 may also include a memory 514 coupled to the processor 512 and capable of being accessed by and storing data in the processor 512. In some implementations, the apparatus 520 may further include a memory 524 coupled to the processor 522 and capable of being accessed by the processor 522 and storing data therein. Each of the memory 514 and the memory 524 may include a random-access memory (RAM), such as Dynamic RAM (DRAM), static RAM (SRAM), thyristor RAM (T-RAM), and/or zero-capacitor RAM (Z-RAM). Alternatively or additionally, each of memory 514 and memory 524 may include a type of read-only memory (ROM), such as mask ROM, programmable ROM (PROM), erasable programmable ROM (erasable programmable ROM, EPROM), and/or electrically erasable programmable ROM (erasable programmable ROM, EEPROM). Alternatively or additionally, each of the memory 514 and the memory 524 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 apparatus 510 and the apparatus 520 may be communication entities capable of communicating with each other using various proposed schemes according to the present invention. For illustrative purposes, and not limitation, the following description of the ability of device 510 as either MLD 110 or MLD 120 (MLD 110 and MLD 120 are non-AP MLDs) and device 520 as MLD 130 (MLD 130 is an AP MLD) is provided. It is noted that while the example embodiments described below are provided in the context of a WLAN, they may be implemented in other types of networks as well.

Under the proposed scheme in accordance with the present invention for an EMLSR channel access procedure in wireless communications, the processor 512 of the device 510 as a first MLD (e.g., MLD 110 or MLD 120) determines that once (in an event that, which may also be described as "if") a frame exchange of the device 510 with a second MLD on a second link of the plurality of EMLSR links is to be initiated upon expiration of a back-off timer of the second link-related (regarding) or upon receipt of a request frame of the second link-related, that frame exchange on the second link will overlap with the receipt of one or more frames from the second MLD (e.g., device 520) to the device 510 on the first link of the plurality of EMLSR links. Further, in response to the determination, the processor 512 refrains from (also described as "refraining") from: (i) A frame exchange is initiated on the second link upon expiration of the back-off timer in response to the expiration of the second link, or (ii) a requested frame (a solicited frame) is sent on the second link in response to the receipt of a soliciting frame (soliciting frame), e.g., the soliciting frame includes a solicited-to-send (RTS) frame or a trigger frame (trigger frame), the requested frame includes a clear-to-send (CTS) frame or a trigger-based (TB) physical-layer protocol data unit (physical-layer protocol data unit, PPDU).

In some implementations, the processor 512 defers (defers) the frame exchange to a time after the reception of the one or more frames on the first link ends (a time after an end of the reception) in avoiding initiating the frame exchange.

In some embodiments, during deferred frame exchanges, processor 512 initiates the frame exchanges after a CCA (clear channel assessment) on the second link indicates that the second link is clear (clear) for transmission (i.e., indicates that the second link is a transmissible link), which CCA is performed after the end of the reception of one or more frames on the first link. For example, processor 512 may perform CCA on the second link after the reception of one or more frames on the first link is completed. Further, the processor 512 may invoke at least one backoff procedure on the second link when the CCA indicates that the second link is clear and available for transmission. Further, the processor 512 may initiate a frame exchange on the second link upon expiration (expiration) of the at least one backoff procedure.

In some embodiments, the receiving of the one or more frames may include receiving one or more group-addressed MPDUs (group-addressed MPDUs).

In some implementations, the receiving of the one or more frames may include receiving one or more beacon frames, wherein each beacon frame includes a DTIM (delivery traffic indication message).

In some implementations, the frame exchange may include transmission of an RTS frame.

Under another proposed scheme in accordance with the present invention for an EMLSR channel access procedure in wireless communications, the processor 512 of the device 510 as a first MLD (e.g., MLD 110 or MLD 120) determines that there is an overlap between a frame exchange on a second link of a plurality of EMLSR links and reception of one or more frames from the second MLD (e.g., device 520) to the device 510 on a first link of the plurality of EMLSR links if the frame exchange with the second MLD on the second link begins when a back-off timer associated with the second link expires. Further, in response to the determination, processor 512 may delay the exchange of frames on the second link to a time after the receipt of one or more frames on the first link ends.

In some implementations, during deferred frame exchanges, processor 512 may initiate frame exchanges after a CCA on the second link indicates that the second link is clean and available for transmission, where the CCA is performed after the end of the reception of one or more frames on the first link. For example, processor 512 may perform CCA on the second link after the reception of one or more frames on the first link is completed. Further, the processor 512 may invoke at least one backoff procedure on the second link when the CCA indicates that the second link is clear and available for transmission (clear for transmission). Further, the processor 512 may initiate a frame exchange on the second link upon expiration of the at least one backoff procedure.

In some implementations, the receiving of the one or more frames may include receiving of one or more group-addressed MPDUs.

Illustrative procedure

Fig. 6 illustrates an example method 600 according to an embodiment of the invention. Process 600 may represent aspects of implementing the various proposed designs, concepts, schemes, systems and methods described above. More particularly, process 600 may represent aspects of the proposed concepts and schemes related to an EMLSR channel access procedure in wireless communications according to the present invention. Process 600 may include one or more operations, actions, or functions as illustrated by one or more of blocks 610 and 620. Although illustrated as discrete blocks, the blocks of process 600 may be divided into additional blocks, combined into fewer blocks, or removed depending on the desired implementation. Furthermore, the blocks/sub-blocks of process 600 may be performed in the order shown in fig. 6, or, alternatively, in a different order. Further, one or more blocks/sub-blocks of process 600 may be repeated or iteratively performed. Process 600 may be implemented by apparatus 510 and apparatus 520, and any variations thereof, or in apparatus 510 and apparatus 520. For purposes of illustration only and not limitation, the process 600 is described in the context of the device 510 as an MLD 110 or an MLD 120 (e.g., a non-AP MLD) of a wireless network and the device 520 as an MLD 130 (e.g., a peer STA MLD or an AP MLD) of a wireless network, such as a WLAN according to one or more IEEE 802.11 standards. Process 600 may begin at block 610.

At 610, process 600 may include: the processor 512 of the device 510 as the first MLD (e.g., MLD 110 or MLD 120) determines that if the frame exchange on the second link of the plurality of EMLSR links by the device 510 and the second MLD (e.g., device 520) is to begin if either case (i) or (ii) occurs, there is an overlap with the reception of one or more frames from the second MLD to the device 510 on the first link of the plurality of EMLSR links, wherein (i) a backoff timer associated with the second link expires; (ii) A request frame (e.g., an RTS frame or a trigger frame) is received in connection with the second link. Process 600 may proceed from 610 to 620.

At 620, process 600 may include: in response to this determination, processor 512 refrains from occurrence of either (i) or (ii) below: (i) Initiating a frame exchange on the second link upon expiration of a back-off timer associated with the second link in response to the expiration of the back-off timer; (ii) The requested frame (e.g., a CTS frame or a TB PPDU) is transmitted on the second link in response to receiving the request frame.

In some implementations, in avoiding initiating a frame exchange, process 600 may include: processor 512 delays the frame exchange to a time after the reception of one or more frames on the first link ends.

In some implementations, in deferring a frame exchange, process 600 may include: the processor 512 initiates a frame exchange after a CCA on the second link, the CCA being performed after the end of the reception of the one or more frames on the first link, and the CCA indicating that the second link is clean available for transmission. For example, process 600 may include: processor 512 performs CCA on the second link after the reception of one or more frames on the first link is completed. Additionally, process 600 may include: the processor 512 invokes at least one backoff procedure on the second link when the CCA indicates that the second link is clear for transmission. Further, process 600 may include: processor 512 initiates a frame exchange on the second link upon expiration of the at least one backoff procedure.

Fig. 7 illustrates an example method 700 according to an embodiment of the invention. Method 700 may represent aspects of designs, concepts, schemes, systems, and methods that implement the various proposals described above. More particularly, method 700 may represent aspects of the proposed concepts and schemes related to EMLSR channel access procedures in wireless communications according to the present invention. The method 700 may include one or more operations, actions, or functions as illustrated by one or more of blocks 710 and 720. Although illustrated as separate blocks, the blocks of method 700 may be separated into additional blocks, combined into fewer blocks, or removed depending on the desired implementation. Furthermore, the blocks/sub-blocks of method 700 may be performed in the order shown in fig. 7, or, alternatively, in a different order. Further, one or more blocks/sub-blocks of method 700 may be repeated or iteratively performed. Method 700 may be implemented by apparatus 510 and apparatus 520, and any variations thereof, or in apparatus 510 and apparatus 520. For purposes of illustration only and not limitation, the method 700 is described in a wireless network in which the apparatus 510 acts as an MLD 110 or an MLD 120 (e.g., a non-AP MLD) and the apparatus 520 acts as an MLD 130 (e.g., a peer STA MLD or an AP MLD), such as a WLAN according to one or more IEEE 802.11 standards. The method 700 may begin at block 710.

At 710, the method 700 may include: the processor 512 of the device 510 as a first MLD (e.g., MLD 110 or MLD 120) determines that if the frame exchange of the device 510 with a second MLD on a second link of the plurality of EMLSR links is to begin when a back-off timer associated with the second link expires, the frame exchange will overlap with the reception of one or more frames from the second MLD to the device 510 on the first link of the plurality of EMLSR links. Method 700 may proceed from 710 to 720.

At 720, method 700 may include: in response to the determination, the processor 512 delays the exchange of frames on the second link to a time after the receipt of one or more frames on the first link ends.

In some implementations, in deferring a frame exchange, method 700 may include: the processor 512 initiates a frame exchange after a CCA on the second link and in a case where the CCA indicates that the second link is clean and available for transmission, wherein the CCA is performed after the reception of one or more frames on the first link is completed. For example, method 700 may include: processor 512 performs CCA on the second link after the reception of one or more frames on the first link is completed. Additionally, method 700 may include: the processor 512 invokes at least one backoff procedure on the second link when the CCA indicates that the second link is clear for transmission. Furthermore, the method 700 may include: processor 512 initiates a frame exchange on the second link upon expiration of the at least one backoff procedure.

In some implementations, the receiving of the one or more frames may include receiving one or more beacon frames, wherein each beacon frame includes a DTIM.

Additional description

The subject matter described herein sometimes illustrates different components contained within or connected with other different components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures can be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality is achieved. Thus, 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 also 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 coupled," to each other to achieve the desired functionality. Specific examples of operably coupled 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 depending on the context and/or application. For clarity, various singular/plural permutations may be explicitly set forth herein.

Furthermore, it will be understood by those of ordinary skill in the art that terms used herein, and particularly those used in the appended claims, such as the subject matter of the appended claims, are generally intended as "open" terms such as the term "comprising" should be interpreted as "including but not limited to," the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," etc. It will be further appreciated by those of ordinary skill in the art that if a specific number of an introduced claim element is intended, such intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, to facilitate understanding, an appended request term may contain the use of the introductory phrases "at least one" and "one or more" to introduce request term elements. However, the use of such phrases should not be construed to imply that the introduction of a request element by the indefinite articles "a" or "an" limits any particular request element containing such introduced request element to only one such element, even when the same request element contains the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an", e.g. "an" and/or "an" are to be interpreted to mean "at least one" or "one or more", as well as to the use of the indefinite articles used to introduce a request element. Furthermore, even if a specific number of an introduced claim element is explicitly recited, those of ordinary skill in the art will recognize that such recitation should be interpreted to mean at least the recited number, such as the bare recitation of "two elements," without other modifiers, meaning at least two elements, or two or more elements. Further, where a structure similar to "at least one of a, B, and C, etc." is used, for its purpose, such a construction is typical, and one having ordinary skill in the art would understand this convention, e.g. "the system has at least one of a, B, and C" would include, but not be limited to, the system having a alone, B alone, C, A alone and B together, a and C together, B and C together, and/or A, B and C together, etc. Where a structure similar to "at least one of a, B, or C, etc." is used, for its purpose, such a construction is typical, and one having ordinary skill in the art would understand the convention, e.g. "a system has at least one of a, B, or C" would include, but not be limited to, a system having a alone, B alone, C, A and B together, a and C together, B and C together, and/or A, B and C together, etc. Those of ordinary skill in the art will further understand that virtually any disjunctive word and/or phrase presenting two or more alternatives, whether in the description, request, or drawings, should be understood to contemplate the possibilities of including one of the plurality of terms, either of the plurality of terms, or both terms. For example, the phrase "a or B" will be understood to include the possibilities of "a" or "B" or "a and B".

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

In the claims, ordinal terms such as "first," "second," "third," etc., are used to modify a claim element, and do not by itself connote any priority, precedence, or order of one claim element over another or the temporal order in which acts of a method are performed, but are used merely as labels to distinguish one claim element having a same name from another element having a same name using the ordinal term.

While the application has been described by way of example and in terms of preferred embodiments, it is to be understood that the application is not limited to the disclosed embodiments. On the contrary, it is intended to cover various modifications and similar arrangements (as will be apparent to those skilled in the art), e.g., combinations or alternatives of the different features in the different embodiments. The scope of the following claims is, therefore, to be accorded the broadest interpretation so as to encompass all such modifications and similar structures.

Claims

1. A method of wireless communication, comprising:

the first multi-link device MLD determining that if a frame exchange of the first MLD with the second MLD on a second link of the plurality of enhanced multi-link single-radio EMLSR links is to begin when a back-off timer associated with the second link expires or when a request frame associated with the second link is received, the frame exchange will overlap with reception of one or more frames from the second MLD to the first MLD on a first link of the plurality of EMLSR links; the method comprises the steps of,

in response to the determination, the first MLD refrains from initiating the frame exchange on the second link upon expiration of the back-off timer in response to expiration of the back-off timer associated with the second link or refrains from transmitting the requested frame on the second link in response to receiving the request frame.

2. The method of claim 1, wherein avoiding initiating the frame exchange comprises: the frame exchange is deferred until a time after the reception of the one or more frames on the first link ends.

3. The method of claim 2, wherein deferring the frame exchange comprises:

performing a clear channel assessment, CCA, for the second link after the reception of the one or more frames on the first link is completed;

Invoking at least one backoff procedure on the second link when the CCA indicates that the second link is clear for transmission; the method comprises the steps of,

the frame exchange is initiated on the second link upon expiration of the at least one backoff procedure.

4. The method of claim 2, wherein deferring the frame exchange comprises: the frame exchange is initiated after a clear channel assessment, CCA, on the second link and in a case where the CCA indicates that the second link is clear for transmission, wherein the CCA is performed after reception of the one or more frames on the first link is over.

5. The method of claim 1, wherein the receiving of the one or more frames comprises: one or more groups address the reception of media access control, MAC, protocol data unit MPDUs.

6. The method of claim 1, wherein the receiving of the one or more frames comprises: and receiving one or more beacon frames, wherein each beacon frame comprises a delivery service indication message (DTIM).

7. The method of claim 1, wherein the request frame comprises: request to send an RTS frame or a trigger frame, and the requested frame includes: the CTS frame or the trigger-based TB physical layer protocol data unit PPDU is cleared.

8. A method of wireless communication, comprising:

the first multi-link device MLD determining that if a frame exchange of the first MLD with the second MLD on a second link of the plurality of enhanced multi-link single-radio EMLSR links is to begin when a back-off timer associated with the second link expires, the frame exchange will overlap with reception of one or more frames from the second MLD to the first MLD on a first link of the plurality of EMLSR links; the method comprises the steps of,

in response to the determination, the first MLD delays the frame exchange to a time after receipt of the one or more frames on the first link ends.

9. The method of claim 8 wherein deferring the frame exchange comprises:

10. The method of claim 8 wherein deferring the frame exchange comprises: the frame exchange is initiated after a clear channel assessment, CCA, on the second link and in a case where the CCA indicates that the second link is clear for transmission, wherein the CCA is performed after reception of the one or more frames on the first link is over.

11. The method of claim 8, wherein the receiving of the one or more frames comprises: one or more groups address the reception of media access control, MAC, protocol data unit MPDUs.

12. The method of claim 8, wherein the receiving of the one or more frames comprises: and receiving one or more beacon frames, wherein each beacon frame comprises a delivery service indication message (DTIM).

13. The method of claim 8 wherein the frame exchange includes requesting transmission of an RTS frame.

14. A wireless communications apparatus that can be implemented in a first multi-link device MLD, comprising:

a transceiver configured to wirelessly communicate with a second MLD; the method comprises the steps of,

a processor coupled to the transceiver and configured to:

determining that if a frame exchange of the first MLD and the second MLD on a second link of the plurality of enhanced multi-link single-radio EMLSR links begins when a back-off timer associated with the second link expires or when a request frame associated with the second link is received, the frame exchange will overlap with reception of one or more frames from the second MLD to the first MLD on a first link of the plurality of EMLSR links; the method comprises the steps of,

In response to the determination, refraining from initiating the frame exchange on the second link upon expiration of the back-off timer in response to expiration of the back-off timer associated with the second link or refraining from transmitting the requested frame on the second link in response to receiving the request frame.

15. The apparatus of claim 14, wherein refraining from initiating the frame exchange comprises: the frame exchange is deferred until a time after the reception of the one or more frames on the first link ends.

16. The apparatus of claim 15, wherein deferring the frame exchange comprises:

17. The apparatus of claim 15, wherein deferring the frame exchange comprises: the frame exchange is initiated after a clear channel assessment, CCA, on the second link and in a case where the CCA indicates that the second link is clear for transmission, wherein the CCA is performed after reception of the one or more frames on the first link is over.

18. The apparatus of claim 14, wherein the receiving of the one or more frames comprises: one or more groups address the reception of media access control, MAC, protocol data unit MPDUs.

19. The apparatus of claim 14, wherein the receiving of the one or more frames comprises: and receiving one or more beacon frames, wherein each beacon frame comprises a delivery service indication message (DTIM).

20. The apparatus of claim 14, wherein the request frame comprises: request to send an RTS frame or a trigger frame, and the requested frame includes: the CTS frame or the trigger-based TB physical layer protocol data unit PPDU is cleared.