Patent Application
20240205973
Various exemplary embodiments disclosed herein relate to clear to send (CTS) frame transmission on a non-primary channel.
Multi-user request to send (MU-RTS) Trigger frame indicates whether the clear to send (CTS) frame is to be sent on the primary 20 MHz channel, primary 40 MHz channel, primary 80 MHz channel, primary 160 MHz channel, 80+80 MHz channel, or 320 MHz channel. The MU-RTS/CTS procedure may incur unnecessary resource waste and reduce transmission opportunities within the basic service set (BSS). The transmit opportunity (TXOP) protection mechanism using an RTS or an MU-RTS Trigger frame does not provide the TXOP protection to an subchannel selective transmission (SST) non-access point (AP) station (STA).
A summary of various exemplary embodiments is presented below.
Various embodiments relate to a method including: transmitting, by an access point (AP), a multi-user request to send (MU-RTS) frame requesting a non-AP station (non-AP STA) to respond with a clear to send (CTS) frame on one or more 20 MHz non-primary subchannels; and receiving, by the AP, a CTS frame from the non-AP STA on the one or more 20 MHz non-primary subchannels.
Various embodiments are described, wherein the non-AP STA may respond on at least one of a plurality of 20 MHz non-primary subchannels and wherein the received CTS frame is received on at least one of the plurality of 20 MHz non-primary channels.
Various embodiments are described, wherein the non-AP STA may respond on at least one of a plurality of 20 MHz non-primary subchannels when at least one of the plurality of 20 MHz non-primary channels is idle.
Various embodiments are described, wherein the CTS frame is further transmitted on a 20 MHz primary channel in addition to the one or more 20 MHz non-primary subchannels.
Various embodiments are described, wherein the non-AP STA is a subchannel selective transmission (SST) non-AP STA.
Various embodiments are described, further including sending, by the AP, sub-band scheduling information to the non-AP STA.
Various embodiments are described, wherein the MU-RTS frame includes resource unit (RU) allocation bitmap indicating 20 MHz non-primary subchannels that may be used by the non-AP STA for a CTS frame transmission.
Various embodiments are described, wherein the MU-RTS frame includes RU allocation control subfield indicating if the RU allocation bitmap is used by the non-AP STA for a CTS frame transmission.
Various embodiments are described, wherein the MU-RTS frame includes a bit indication that indicates where the RU allocation bitmap subfield or the RU allocation subfield indicates a non-primary channel.
Further various embodiments relate to a method including: receiving, by a non-access point station (non-AP STA) from an access point (AP), an multi-user request to send (MU-RTS) indicating that the non-AP STA responds with a clear to send (CTS) frame on one or more 20 MHz non-primary subchannels; performing, by the non-AP STA, a carrier sense operation on the one or more 20 MHz non-primary subchannels to determine whether the 20 MHz non-primary subchannel is idle; and transmitting, by the non-AP STA, a CTS frame on the one or more 20 MHz non-primary subchannels when the corresponding 20 MHz non-primary subchannel is idle based on the carrier sense operation.
Various embodiments are described, wherein the non-AP STA may respond on at least one of a plurality of 20 MHz non-primary subchannels and wherein the CTS frame is transmitted on at least one of the plurality of 20 MHz non-primary channels.
Various embodiments are described, wherein the non-AP STA may transmit the CTS frame on at least one of a plurality of 20 MHz non-primary subchannels when at least one of the plurality of 20 MHz non-primary channels is idle.
Various embodiments are described, wherein the CTS frame is further transmitted on a 20 MHz primary channel in addition to the one or more 20 MHz non-primary subchannels.
Various embodiments are described, wherein the non-AP STA is a subchannel selective transmission (SST) non-AP STA.
Various embodiments are described, further including receiving, by the non-AP STA, from the AP sub-band scheduling information.
Various embodiments are described, wherein the MU-RTS frame includes resource unit (RU) allocation bitmap indicating 20 MHz non-primary subchannels that may be used by the non-AP STA for a CTS frame transmission.
Various embodiments are described, wherein the MU-RTS frame includes RU allocation control subfield indicating if the RU allocation bitmap is used by the non-AP STA for a CTS frame transmission.
Various embodiments are described, wherein the MU-RTS frame includes a bit indication that indicates where the RU allocation bitmap subfield or the RU allocation subfield indicates a non-primary subchannel allocation.
Further various embodiments relate to an access point (AP), including a processor configured to: transmit a multi-user request to send (MU-RTS) frame requesting a non-AP station (non-AP STA) to respond with a clear to send (CTS) frame on one or more 20 MHz non-primary subchannels; and receive a CTS frame from the non-AP STA on the one or more 20 MHz non-primary subchannels.
Further various embodiments relate to a non-access point station (non-AP STA), including a processor configured to: receive an multi-user request to send (MU-RTS) indicating that the non-AP STA responds with a clear to send (CTS) frame on one or more 20 MHz non-primary subchannels; perform a carrier sense operation on the one or more 20 MHz non-primary subchannels to determine whether the 20 MHz non-primary subchannel is idle; and transmit a CTS frame on the one or more 20 MHz non-primary subchannels when the corresponding 20 MHz non-primary subchannel is idle based on the carrier sense operation.
The foregoing has outlined rather broadly the features and technical advantages of examples according to the disclosure in order that the detailed description that follows may be better understood. Additional features and advantages will be described hereinafter. The conception and specific examples disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present disclosure. Such equivalent constructions do not depart from the scope of the appended claims. Characteristics of the concepts disclosed herein, both their organization and method of operation, together with associated advantages will be better understood from the following description when considered in connection with the accompanying figures. Each of the figures is provided for the purposes of illustration and description, and not as a definition of the limits of the claims.
So that the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects. The same reference numbers in different drawings may identify the same or similar elements.
Various aspects of the disclosure are described more fully hereinafter with reference to the accompanying drawings. This disclosure may, however, be embodied in many different forms and should not be construed as limited to any specific structure or function presented throughout this disclosure. Rather, these aspects are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art. Based on the teachings herein one skilled in the art should appreciate that the scope of the disclosure is intended to cover any aspect of the disclosure disclosed herein, whether implemented independently of or combined with any other aspect of the disclosure. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to or other than the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim.
Several aspects of wireless networks with primary link operation with single radio MLD or NSTR AP MLD systems will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, and/or the like (collectively referred to as “elements”). These elements may be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.
Several aspects of WiFi systems will now be presented with reference to various apparatuses and techniques. These apparatuses and techniques will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, modules, components, circuits, steps, processes, algorithms, and/or the like (collectively referred to as “elements”). These elements may be implemented using hardware, software, or combinations thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.
Although the depicted multi-link communications system 10 is shown in
In the embodiment depicted in
In some embodiments, an AP MLD (e.g., AP MLD 1) connects to a local area network (e.g., a LAN) and/or to a backbone network (e.g., the Internet) through a wired connection and wirelessly connects to wireless STAs, for example, through one or more WLAN communications protocols, such as an IEEE 802.11 protocol. In some embodiment, an AP (e.g., AP18-1 and/or AP28-2) includes multiple RF chains. In some embodiments, an AP (e.g., AP18-1 and/or AP28-2) includes at least one antenna, at least one transceiver operably connected to the at least one antenna, and at least one controller operably connected to the corresponding transceiver. In some embodiments, at least one transceiver includes a physical layer (PHY) device. The at least one controller may be configured to control the at least one transceiver to process received packets through the at least one antenna. In some embodiments, the at least one controller may be implemented within a processor, such as a microcontroller, a host processor, a host, a digital signal processor (DSP), or a central processing unit (CPU), which can be integrated in a corresponding transceiver. In some embodiments, each of the APs 8-1 or 8-2 of the AP MLD 1 with multiple RF chains may operate in a different basic service set (BSS) operating channel (in a different link). For example, AP18-1 may operate in a 320 MHz BSS operating channel at 6 GHz band, and AP28-2 may operate in a 160 MHz BSS operating channel at 5 GHz band. Although the AP MLD 1 is shown in
In the embodiment depicted in
In some embodiments, the AP MLD 1 and/or the STA MLD 13 may identify which communication links support multi-link operation during a multi-link operation setup phase and/or exchanges information regarding multi-link capabilities during the multi-link operation setup phase. In some embodiments, each of the non-AP STAs 5-1 and 5-2 of the STA MLD 13 in different link may operate in a different frequency band. For example, the non-AP STA15-1 in one link may operate in the 2.4 GHz frequency band and the non-AP STA25-2 in another link may operate in the 5 GHz frequency band. In some embodiments, each STA includes at least one antenna, at least one transceiver operably connected to the at least one antenna, and at least one controller connected to the corresponding transceiver. In some embodiments, at least one transceiver includes a PHY device. The at least one controller may be configured to control the at least one transceiver to process received packets through the at least one antenna. In some embodiments, the at least one controller may be implemented within a processor, such as a microcontroller, a host processor, a host, a DSP, or a CPU, which can be integrated in a corresponding transceiver.
In the embodiment depicted in
As described above a multi-link AP MLD has one or multiple links where each link has one AP affiliated with the AP MLD. This may be accomplished by having the different radios for the different affiliated APs.
A multi-link STA MLD has one or multiple links where each link has one STA affiliated with the STA MLD. One way to implement the multi-link STA MLD is using two or more radios, where each radio is associated with a specific link. For example, an multi-link multi-radio (MLMR) non-AP MLD may be used. The MLMR non-AP MLD uses multiple full functional radios to monitor the medium in multiple links. Another way to implement the multi-link STA MLD is using a single radio in two different bands. Each band may be associated with a specific link. In this case only one link is available at a time. In yet another implementation, an enhanced single-radio (ESR) STA MLD may be used that operates in an enhanced multi-link single radio (cMLSR) mode. The ESR STA MLD uses two radios in different bands to implement the MLD. For example, one radio may be a lower cost radio with lesser capabilities and the other radio may be a fully functional radio supporting the latest protocols. The ESR STA MLD may dynamically switch its working link while it can only transmit or receive through one link at any time. The ESR STA MLD may monitor two links simultaneously, for example, detecting medium idle/busy status of each link, or receiving a PPDU on each link. Each radio may have its own backoff time, and when the backoff counter for one of the radios becomes zero that radio and link may be used for transmission. For example, if an AP wants to use the fully functional radio, it may send a control frame that is long enough for the ESR STA MLD to switch from the lesser capable radio to the fully functional radio that may then transmit data to the AP. When an ESS includes multiple AP MLDs in different locations and a STA MLD executed the data frame exchanges with one of the AP MLDs (say AP MLD1), as the STA MLD's associated AP MLD moves to other location to do the data frame exchanges with another one of the AP MLDs (say AP MLD2), the STA MLD (same as a non-AP MLD herein) needs to finish the association with AP MLD2 before doing the data frame exchanges with AP MLD2. There is a requirement to decrease the number of associations within the ESS.
Multi-user request to send (MU-RTS) Trigger frame indicates whether the clear to send (CTS) frame is to be sent on the primary 20 MHz channel, primary 40 MHz channel, primary 80 MHz channel, primary 160 MHz channel, 80+80 MHz channel, or 320 MHz channel. The MU-RTS/CTS procedure may incur unnecessary resource waste and reduce transmission opportunities within the basic service set (BSS). The transmit opportunity (TXOP) protection mechanism using an RTS or an MU-RTS Trigger frame does not provide the TXOP protection to an subchannel selective transmission (SST) non-access point (AP) station (STA).
Embodiments of CTS frame transmission include the following features. The CTS frame in response to an MU-RTS frame can be transmitted on secondary channel only. The CTS frame in response to an MU-RTS frame can be transmitted on the primary 20 MHz channel and on secondary subchannel(s). The CTS frame in response to an MU-RTS frame can be transmitted by an SST non-AP STA and a sub-band scheduled non-AP STA. The CTS frame in response to an MU-RTS frame can be transmitted even when one of the allocated subchannel is busy.
The MU-RTS Trigger/CTS frame exchange sequence procedure allows an AP to initiate a TXOP and protect the TXOP frame exchange sequences. An AP may transmit an MU-RTS Trigger frame to solicit simultaneous CTS frame transmissions from one or more non-AP STAs.
The RU Allocation subfield in the User Info field of the MU-RTS Trigger frame addressed to the non-AP STA indicates whether the CTS frame is to be sent on the primary 20 MHz channel, primary 40 MHz channel, primary 80 MHz channel, primary 160 MHz channel, 80+80 MHz channel, or 320 MHz channel.
In SST operation, an HE STA that supports HE SST operation is an HE SST non-AP STA. An HE AP that supports HE subchannel selective transmission (SST) operation is an HE SST AP. An HE SST non-AP STA and an HE SST AP may set up SST operation by negotiating a trigger-enabled target wake time (TWT) as defined in 26.8.2 (Individual TWT agreements) of the IEEE 802.11 specification with the following exceptions.
The TWT request may have a TWT Channel field with up to one bit set to 1 to indicate the secondary channel requested to contain the resource unit (RU) allocations addressed to the HE SST non-AP STA that is a 20 MHz operating STA. The TWT request may have a TWT Channel field with all 4 LSBs or all 4 MSBs set to 1 to indicate whether the primary 80 MHZ channel or the secondary 80 MHz channel is requested to contain the RU allocations addressed to the HE SST non-AP STA that is an 80 MHz operating STA. The TWT response shall have a TWT Channel field with up to one bit set to 1 to indicate the secondary channel that will contain the RU allocations addressed to the HE SST non-AP STA that is a 20 MHz operating STA. The TWT response shall have a TWT Channel field with all 4 LSBs or all 4 MSBs set to 1 to indicate whether the primary 80 MHz channel or the secondary 80 MHz channel will contain the RU allocations addressed to the HE SST non-AP STA that is a 80 MHz operating STA.
The HE SST AP follows the rules in section 26.8.2 (Individual TWT agreements) of the IEEE 802.11 specification to exchange frames with the HE SST non-AP STA during trigger-enabled TWT SPs, except that the AP shall ensure the following. The individually addressed RUs allocated in downlink (DL) MU PPDUs and in Trigger frames addressed to the HE SST non-AP STA are within the subchannel indicated in the TWT Channel field of the TWT response and follow the RU restriction rules defined in section 27.3.2.8 (RU restrictions for 20 MHZ operation) of the IEEE 802.11 specification if the HE SST non-AP STA is a 20 MHz operating STA and in section 27.3.2.9 (80 MHz operating non-AP HE STAs) of the IEEE 802.11 specification if the HE SST non-AP STA is an 80 MHz operating STA.
The HE SST non-AP STA follows the rules in section 26.8.2 (Individual TWT agreements) of the IEEE 802.11 specification to exchange frames with the HE SST AP during trigger-enabled TWT SPs, except that the STA shall be available in the subchannel indicated in the TWT Channel field of the TWT response at TWT start times and shall not access the medium in the subchannel using distributed coordination function (DCF) or enhanced distributed channel access function (EDCAF).
There are a number of motivations to allow for a CTS frame in response to a MU-RTS Trigger frame to be carried in a secondary channel.
A CTS frame in response to an MU-RTS Trigger frame can be transmitted on the primary 20 MHz channel, primary 40 MHz channel, primary 80 MHz channel, primary 160 MHZ channel, 80+80 MHz channel, or 320 MHz channel in the non-HT (duplicate) PPDU.
For example, the MU-RTS Trigger frame 302 indicates RU allocations of primary 20 MHz channel to STA1, primary 40 MHz channel to STA2, primary 80 MHz channel to STA3, and primary 160 MHz channel to STA4. The STAs send back CTS frames 304, 306, and 308. If a 20 MHz subchannel of the allocated RU is busy based on the combination of virtual CS and ED-based CCA during the SIFS after the PPDU containing the MU-RTS Trigger frame (e.g., STA4 senses the busy channel of the secondary 20 MHz channel 308), the STA(e.g., STA4) shall not respond with the CTS frame 308. Even though an AP intends to allocate secondary 80 MHz channel resource to STA4 through the following Trigger frame 310, the AP is not able to do it since the AP does not receive CTS frame on the secondary 80 MHz channel from the STA4. It incurs resource waste and reduces transmission opportunities within the BSS. STA1, STA2, and STA3 respond to the Trigger frame 310 with TB PPDUs 312, 314, and 316. The AP then send a multi-STA block acknowledgement (M-BA).
In some situations, more than one CTS frames in response to an MU-RTS Trigger frame may overlap one or more 20 MHz subchannels.
In some situations, an SST non-AP STA may do the subchannel selective transmission operation after individual TWT negotiation.
In another situation, similar to SST operation, if a mechanism is defined for sub-band scheduling operation through non-AP STA's switching to a non-primary sub-band (e.g., secondary 160 MHz sub-band), a non-AP STA may switch to the non-primary sub-band after receiving a sub-band scheduling information from an AP.
Therefore, the existing TXOP protection mechanism using an RTS or an MU-RTS Trigger frame does not provide TXOP protection to a non-primary sub-band scheduled non-AP STA. The AP sends a non-HT Dup PPDU 602 with scheduling information. The AP then sends an MU-RTS 604 and STA1 responds with CTS 606, but STA2 cannot respond 608. The AP then sends a PPDU 610 and STA1 and STA2 respond with BAs 612 and 614.
Various embodiments of CTS transmission using a secondary channel will be described.
A CTS transmission may only be done only on the secondary channel.
For example, an MU-RTS 702 indicates RU allocations of primary 20 MHz channel to STA1, secondary 20 MHz channel to STA2, secondary 40 MHz channel to STA3, and secondary 80 MHz channel to STA4. If a STA senses the allocated channel being idle, STA1, STA2, STA3, and STA4 may respond with a CTS frame 704, 706, 708, and 710 on the allocated 20 MHZ subchannel(s) in a non-HT (duplicate) PPDU. Based on the channel bandwidth of the received CTS frame(s) 704, 706, 708, and 710 (e.g., one or more 20 MHz subchannel(s) where the CTS frame(s) is received), the AP may schedule uplink and/or downlink transmission for non-AP STA(s) during the TXOP. Accordingly, STA1, STA2, STA3, and STA4 may transmit TB PPDUs 714, 716, 718, and 720 respectively. Then the AP responds with a M-BA 722.
A CTS transmission may only be done only on the secondary channel.
A CTS transmission by an SST non-AP STA will now be described.
A CTS transmission may be carried by a sub-band scheduled non-AP STA.
CTS frame detection at an AP will now be discussed. To reduce the complexity for parallel processing of the CTS frame received on 20 MHz subchannels, an AP can do at least one of the following. The AP may detect a CTS frame on a specific 20 MHz subchannel (e.g., virtual control channel for CTS frame reception) per 40 MHz CH or per 80 MHz CH to determine the TXOP BW. For example, if a virtual control channel is assigned per 40 MHz, an AP can detect a CTS frame per 40 MHz channel within the BW (e.g., P40CH and S40CH of P80CH, and 1st 40CH and 2nd 40CH of S80CH in 160 MHz BW, etc.).
The AP may limit the number of allocated RU in an MU-RTS Trigger frame. For example, in the embodiment of
The AP may detect a CTS frame on the primary channel and determine the CTS frame reception based on the energy detection or the preamble detection (e.g., L-STF, L-LTF, etc.) on each 20 MHz subchannel of the secondary channel where the RU is allocated, or, e.g., the clear channel assessment (CCA) result of each 20 MHz subchannel can be used to determine whether a CTS frame is received on the 20 MHz subchannel of the secondary channel.
The foregoing disclosure provides illustration and description but is not intended to be exhaustive or to limit the aspects to the precise form disclosed. Modifications and variations may be made in light of the above disclosure or may be acquired from practice of the aspects.
As used herein, the term “component” is intended to be broadly construed as hardware, firmware, and/or a combination of hardware and software. As used herein, a processor is implemented in hardware, firmware, and/or a combination of hardware and software.
As used herein, satisfying a threshold may, depending on the context, refer to a value being greater than the threshold, greater than or equal to the threshold, less than the threshold, less than or equal to the threshold, equal to the threshold, not equal to the threshold, and/or the like. It will be apparent that systems and/or methods described herein may be implemented in different forms of hardware, firmware, and/or a combination of hardware and software. The actual specialized control hardware or software code used to implement these systems and/or methods is not limiting of the aspects. Thus, the operation and behavior of the systems and/or methods were described herein without reference to specific software code—it being understood that software and hardware can be designed to implement the systems and/or methods based, at least in part, on the description herein.
As used herein, the term “non-transitory machine-readable storage medium” will be understood to exclude a transitory propagation signal but to include all forms of volatile and non-volatile memory. When software is implemented on a processor, the combination of software and processor becomes a specific dedicated machine.
Because the data processing implementing the embodiments described herein is, for the most part, composed of electronic components and circuits known to those skilled in the art, circuit details will not be explained in any greater extent than that considered necessary as illustrated above, for the understanding and appreciation of the underlying concepts of the aspects described herein and in order not to obfuscate or distract from the teachings of the aspects described herein.
Unless stated otherwise, terms such as “first” and “second” are used to arbitrarily distinguish between the elements such terms describe. Thus, these terms are not necessarily intended to indicate temporal or other prioritization of such elements.
It should be appreciated by those skilled in the art that any block diagrams herein represent conceptual views of illustrative hardware embodying the principles of the aspects.
While each of the embodiments are described above in terms of their structural arrangements, it should be appreciated that the aspects also cover the associated methods of using the embodiments described above.
Unless otherwise indicated, all numbers expressing parameter values and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by embodiments of the present disclosure. As used herein, “about” may be understood by persons of ordinary skill in the art and can vary to some extent depending upon the context in which it is used. If there are uses of the term which are not clear to persons of ordinary skill in the art, given the context in which it is used, “about” may mean up to plus or minus 10% of the particular term.
Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of various aspects. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one claim, the disclosure of various aspects includes each dependent claim in combination with every other claim in the claim set. A phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).
No element, act, or instruction used herein should be construed as critical or essential unless explicitly described as such. Also, as used herein, the articles “a” and “an” are intended to include one or more items and may be used interchangeably with “one or more.” Furthermore, as used herein, the terms “set” and “group” are intended to include one or more items (e.g., related items, unrelated items, a combination of related and unrelated items, and/or the like), and may be used interchangeably with “one or more.” Where only one item is intended, the phrase “only one” or similar language is used. Also, as used herein, the terms “has,” “have,” “having,” and/or the like are intended to be open-ended terms. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.
This application claims the benefit of U.S. Provisional Patent Application No. 63/387,700, filed Dec. 16, 2022, the contents of which are incorporated for all purposes by reference herein in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63387700 | Dec 2022 | US |
