Systems for communicating with unassociated stations

Methods and apparatus for communicating in a wireless network. In one aspect, a first wireless communication device may generate a first frame that includes at least a first aggregated media access control protocol data unit (A-MPDU). The first A-MPDU may include one or more media access control protocol data units (MPDUs). The first wireless communication device may set a first recipient address (RA) field to a first value in a first MPDU, and set a first field in the first MPDU to a second value that represents an identifier of a second wireless communication device. In one aspect, the first wireless communication device may set a second field in the first MPDU to a third value that represents an identifier of a third wireless communication device. The wireless communication device may output the first frame for transmission to at least the second and third wireless communication devices.

TECHNICAL FIELD

This disclosure relates generally to wireless communications, and more specifically, to communicating with unassociated stations.

DESCRIPTION OF THE RELATED TECHNOLOGY

A wireless local area network (WLAN) may be formed by one or more access points (APs) that provide a shared wireless communication medium for use by one or more client devices, also referred to as stations (STAs). The basic building block of a WLAN conforming to the IEEE 802.11 family of standards is a Basic Service Set (BSS), which is managed by an AP that serves one or more STAs. Each BSS is identified by a service set identifier (SSID) that is advertised by the AP.

An AP periodically broadcasts beacon frames to enable any STAs within wireless range of the AP to establish and/or maintain a communication link with the WLAN. To identify an AP with which to associate, a STA may wait to receive a beacon frame from an AP or may be configured to perform active scans on the wireless channels of each of one or more frequency bands by sending one or more probe requests to elicit one or more probe responses from one or more APs. Using the information received in a beacon or a probe response, a STA may select an AP from one or more available APs within range of the STA. The STA may then associate with the selected AP and begin data communication through the AP after completion of the association process.

In some situations, an AP may send a communication that will be received by one or more STAs that are not already associated with the AP. The communication from the AP may be included in a single-user (SU) data unit directed to a single station, or a multi-user (MU) data unit directed to multiple stations. The use of an MU data unit for communicating with unassociated stations may introduce a few issues that could benefit from new ways to communicate between an AP and unassociated stations.

SUMMARY

One innovative aspect of the subject matter described in this disclosure can be implemented by a first wireless communication device. The first wireless communication device may generate a first frame that includes at least a first aggregated media access control protocol data unit (A-MPDU). The first A-MPDU may include one or more media access control protocol data units (MPDUs). The first wireless communication device may set a first recipient address (RA) field to a first value in a first MPDU of the one or more MPDUs in the first A-MPDU. The first wireless communication device may set a first field in the first MPDU to a second value. The first wireless communication device may output the first frame for transmission to at least a second wireless communication device.

In some implementations, the first wireless communication device may set the first field to the second value that represents an identifier of the second wireless communication device. The first wireless communication device also may set a second field in the first MPDU to a third value, different than the second value, that represents an identifier of a third wireless communication device. The first wireless communication device may output the first frame for transmission to at least the second and third wireless communication devices.

In some implementations, the first frame may be a Multi-Station (Multi-STA) BlockAck (BA) frame. The first wireless communication device setting the first RA field may include setting the first RA field to a broadcast address. The first wireless communication device setting the first field may include setting a first RA subfield of the first field to a first media access control (MAC) address associated with the second wireless communication device. The first wireless communication device setting the second field may include setting a second RA subfield of the second field to a second MAC address associated with the third wireless communication device.

In some implementations, the first frame may be included in a resource unit of a downlink (DL) multi-user (MU) PPDU having a station identification (STA ID) field set to a value of 2045, which may indicate a broadcast communication with one or more unassociated wireless communication devices.

Another innovative aspect of the subject matter described in this disclosure can be implemented by a second wireless communication device. The second wireless communication device may receive a first frame, from a first wireless communication device, that includes at least a first A-MPDU. The first A-MPDU may include one or more MPDUs. The second wireless communication device may decode at least a portion of a first MPDU of the one or more MPDUs in the first A-MPDU and identifying a first RA field in the first MPDU. The second wireless communication device may determine that the first RA field of the first MPDU includes a first value. The second wireless communication device may determine whether a first field in the first MPDU is addressed to the second wireless communication device or a different wireless communication device, in response to the first RA field including the first value.

Another innovative aspect of the subject matter described in this disclosure can be implemented by a wireless communication apparatus of a first wireless communication device. The wireless communication apparatus may include a processor and a transmitter. The processor may be configured to generate a first frame that includes at least a first A-MPDU. The first A-MPDU may include one or more MPDUs. The processor may be configured to set a first RA field to a first value in a first MPDU of the one or more MPDUs in the first A-MPDU, and set a first field in the first MPDU to a second value. The transmitter may be coupled with the processor, and the transmitter may be configured to output the first frame for transmission to at least a second wireless communication device.

Another innovative aspect of the subject matter described in this disclosure can be implemented by a wireless communication apparatus of a second wireless communication device. The wireless communication apparatus may include a receiver and a processor. The receiver may be configured to receive a first frame, from a first wireless communication device, that includes at least a first A-MPDU. The first A-MPDU may include one or more MPDUs. The processor may be coupled with the receiver, and the processor may be configured to decode at least a portion of a first MPDU of the one or more MPDUs in the first A-MPDU and identify a first RA field in the first MPDU. The processor may be configured to determine that the first RA field of the first MPDU includes a first value, and determine whether a first field in the first MPDU is addressed to the second wireless communication device or a different wireless communication device, in response to a determination that the first RA field includes the first value.

DETAILED DESCRIPTION

The systems and techniques described in this detailed description provide various mechanisms for communicating between a first communication device and one or more other communication devices. These mechanisms may be helpful for enabling communications between an access point (AP) and stations (STAs) that are not already associated with the AP. As one example, an IEEE 802.11ax AP may send a trigger frame (e.g., the trigger frame200ofFIG. 2) that allocates one or more resource units (RUs) for random access communications by STAs that are not currently associated with the AP. An RU may be a sub-channel, within a larger channel bandwidth, that includes a subset of the channel's total available subcarriers. For example, in IEEE 802.11ax, an RU may be a group of 26, 52, 106, 242, 484, or 996 subcarriers (or tones). The RUs may be used by one or more STAs, such as in an orthogonal frequency-division multiple access (OFDMA) system.

After identifying an RU that is allocated for random access communications by unassociated STAs, an unassociated STA may elect to use the allocated RU to send a frame (e.g., a management frame, such as a probe request or association request) to the AP. Multiple unassociated STAs may elect to send a frame to the AP in response to the AP's trigger frame. In some situations, the AP may respond (e.g., send a probe response or association response) to each of these multiple unassociated STAs by sending a single-user (SU) physical layer conformance procedure (PLCP) protocol data unit (PPDU) to each individual STA (which results in multiple SU PPDUs being sent by the AP). In other situations, the AP may try to respond to the multiple unassociated STAs by sending a downlink (DL) multi-user (MU) PPDU. In some situations, the use of the MU PPDU may reduce the number of data units sent by the AP to service the uplink trigger-based messages from the unassociated STAs. The use of an MU PPDU for communicating with unassociated stations may introduce a few issues that could benefit from new ways to communicate between an AP and unassociated stations.

To overcome a first potential issue, a new way to address multiple unassociated stations (e.g., via multiple media access control protocol data unit (MPDUs)) inside of a single aggregated MPDU (A-MPDU) within an MU PPDU may be beneficial in some implementations. An 802.11ax AP may send a downlink MU PPDU having a station identification (STA ID) field set to indicate a broadcast RU for unassociated STAs (e.g., the RU is intended for more than one unassociated STA). The AP may send an A-MPDU on this RU to communicate with multiple different STAs. However, section 9.7.3 of the 802.11-2016 standard states that “[a]ll of the MPDUs within an A-MPDU are addressed to the same RA.” The phrase “the same RA” indicates that the same recipient address (RA) value, which is used to identify the station at which the MPDU is directed, should be used in each MPDU within a single A-MPDU. Therefore, when following this rule, all the MPDUs in the A-MPDU would need to be sent to the same recipient address, which could undermine the ability for some implementations to allow an RU to carry an A-MPDU containing MPDUs intended for more than one STA.

To overcome a second potential issue, a new way to receive further communications (e.g., other than the initial uplink management frame sent in response to the trigger frame) from an unassociated STA at an AP may be beneficial in some implementations. Some implementations of 802.11ax may only allow an unassociated STA to send management frames (e.g., a probe request) using random access communications in response to a trigger frame allocating an RU for unassociated STAs. These implementations of 802.11ax may also limit the AP's response, when responding in a downlink MU PPDU, to only send a management frame (e.g., a probe response). In such implementations, the AP may not be able to solicit an immediate response to its downlink response. For example, an unassociated STA may not have an RU allocated and available for an uplink response message to acknowledge receipt of the downlink MU PPDU (e.g., to acknowledge receipt of a probe response contained within the MU PPDU).

To overcome a third potential issue, a new way to determine whether a STA should process a transmission from an AP containing an RU allocated for unassociated STAs may be beneficial in some implementations. Some implementations of 802.11ax may not specify which unassociated STA(s) are addressed by the AP in the RU allocated for communication with unassociated STAs. For example, some downlink frames may not identify that the frames are only meant for certain unassociated STAs and that other unassociated STAs can ignore these frames. In these situations, all unassociated STAs in the area of the AP may attempt to decode and process a transmission from the AP containing an RU allocated for communications with unassociated STAs. Unassociated STAs that did not previously send a message to the AP in response to the AP's trigger frame may unnecessarily waste processing cycles or battery power to process these incoming frames.

Various solutions to these potential issues will be discussed in more detail below, such as in the descriptions below related toFIGS. 5-20. In some implementations, the AP may send a DL MU PPDU that is directed to all unassociated STAs, having the recipient address (RA) field set to a broadcast address. The AP also may send a DL MU PPDU that is a Multi-STA BlockAck (BA) frame type and is directed to one or more unassociated STAs. The DL MU PPDU may have the RA field set to a broadcast address, and may include RA information for the one or more unassociated STAs in one of the BA fields of the Multi-STA BA frame. The AP also may send a DL MU PPDU that is directed to a single unassociated STA, having the RA field set to an address (such as a media access control (MAC) address) of the unassociated STA. Additional types of DL MU PPDUs are also described here, such as a DL MU PPDU having at least a first MPDU and a second MPDU, where the first MPDU includes a first field having a first value that represents an identifier of a first unassociated STA, and the second MPDU includes a second field having a second value that represents an identifier of a second unassociated STA. Also, note that although several of the solutions and implementations described herein are discussed in the context of communication with an unassociated STA or a group of unassociated STAs, these same solutions and implementations can also be used for communication with a STA or a group of STAs that are already associated with the AP.

FIG. 1is a wireless communication system100illustrating an example of a wireless local area network (WLAN) deployment in connection with various techniques described herein for a first device (e.g., an AP) to provide additional communication characteristics regarding its operation to other devices (e.g., STAs.) The WLAN deployment may include one or more access points (APs) and one or more wireless stations (STAs) associated with a respective AP. In this example, there are two APs deployed for illustrative purposes: AP1105-ain basic service set 1 (BSS1) and AP2105-bin BSS2. BSS1 and BSS2 may be identified by different BSS color indicators in communications to allow receiving devices to differentiate the source BSS of a communication according to which BSS color indicator is included in the communication. AP1105-ais shown having multiple associated STAs (STA1115-a, STA2115-b, STA4115-d, and STA5115-e) and coverage area110-a, while AP2105-bis shown having multiple associated STAs (STA1115-aand STA3115-c) and coverage area110-b. In the example ofFIG. 1, the coverage area of API105-aoverlaps part of the coverage area of AP2105-bsuch that STA1115-ais within the overlapping portion of the coverage areas. The number of BSSs, APs, and STAs, and the coverage areas of the APs described in connection with the WLAN deployment ofFIG. 1are provided by way of illustration and not of limitation. Moreover, aspects of the various techniques described herein are at least partially based on the example WLAN deployment ofFIG. 1but need not be so limited.

The APs (e.g., AP1105-aand AP2105-b) shown inFIG. 1are generally fixed terminals that provide backhaul services to STAs within its coverage area or region. In some applications, however, the AP may be a mobile or non-fixed terminal. The AP may also be a STA, such as a STA operating in an AP role. The STAs (e.g., STA1115-a, STA2115-b, STA3115-c, STA4115-d, and STA5115-e) shown inFIG. 1, which may be fixed, non-fixed, or mobile terminals, utilize the backhaul services of their respective AP to connect to a network (see, e.g., network318inFIGS. 3 and 4), such as the Internet. Examples of a STA include, but are not limited to: a cellular phone, a smart phone, a laptop computer, a desktop computer, a personal digital assistant (PDA), a personal communication system (PCS) device, a personal information manager (PIM), personal navigation device (PND), a global positioning system, a multimedia device, a video device, an audio device, a device for the Internet-of-Things (IoT), or any other suitable wireless apparatus requiring the backhaul services of an AP. A STA may also be referred to by those skilled in the art as: a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless station, a remote terminal, a handset, a user agent, a mobile client, a client, user equipment (UE), or some other suitable terminology. An AP may also be referred to as: a base station, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a small cell, or any other suitable terminology. The various concepts described throughout this disclosure are intended to apply to all suitable wireless apparatus regardless of their specific nomenclature.

Each of STA1115-a, STA2115-b, STA3115-c, STA4115-d, and STA5115-emay be implemented with a protocol stack. The protocol stack can include a physical layer for transmitting and receiving data in accordance with the physical and electrical specifications of the wireless channel, a data link layer for managing access to the wireless channel, a network layer for managing source to destination data transfer, a transport layer for managing transparent transfer of data between end users, and any other layers necessary or desirable for establishing or supporting a connection to a network.

Each of API105-aand AP2105-bcan include software applications and/or circuitry to enable associated STAs to connect to a network via communications links125. The APs can send frames to their respective STAs and receive frames from their respective STAs to communicate data and/or control information (e.g., signaling).

Each of AP1105-aand AP2105-bcan establish a communications link125with a STA that is within the coverage area of the AP. Communications links125can comprise communications channels that can enable both uplink and downlink communications. When connecting to an AP, a STA can first authenticate itself with the AP and then associate itself with the AP. Once associated, a communications link125can be established between the AP and the STA such that the AP and the associated STA can exchange frames or messages through a direct communications channel.

While aspects of the present disclosure are described in connection with a WLAN deployment or the use of IEEE 802.11-compliant networks, those skilled in the art will readily appreciate, the various aspects described throughout this disclosure may be extended to other networks employing various standards or protocols including, by way of example, BLUETOOTH® (Bluetooth), HiperLAN, and other technologies used in wide area networks (WANs), cellular networks, WLANs, personal area networks (PAN)s, or other suitable networks now known or later developed.

FIG. 2illustrates an example of a trigger frame200. An AP may send a trigger frame200to provide a transmission schedule to STAs. For example, the trigger frame200may specify which STAs can transmit during certain times and which subsets of orthogonal frequency-division multiple access (OFDMA) sub-carriers they will use. The trigger frame200solicits and allocates resources for uplink (UL) transmissions (including multi-user (MU) transmissions) scheduled after the Physical Layer Convergence Procedure (PLCP) protocol data unit (PPDU) that carries the trigger frame200. The trigger frame200carries information used by the responding STA to send a trigger-based (TB) PPDU back to the AP. In one implementation, the trigger frame200may include a frame control field202, a duration field204, a recipient address (RA) field206, a transmitter address (TA) field208, a common information field210, one or more user information fields212,214, and216(where field214represents zero or more additional user information fields), padding218, and a frame check sequence (FCS) field220.

As will be discussed in more detail below in connection withFIGS. 5-20, the systems described herein may use the trigger frame200to allocate an RU for random access communications between an AP and unassociated STAs. A receiving STA that is unassociated with the AP may then send a trigger-based message back to the AP that sent the trigger frame200. The trigger-based message may then result in further communications between the AP and the unassociated STA that sent the trigger-based message, as will be discussed further below.

FIG. 3illustrates an example wireless communication system300that includes multiple STAs115in wireless communication with at least one AP105connected to network318. The STAs115may communicate with network318via AP105. In an example, STAs115may transmit and/or receive wireless communication to and/or from AP105via one or more communication links125. Such wireless communications may include, but are not limited to, data, audio and/or video information. In some instances, such wireless communications may include control or similar information. An AP, such as AP105, may be configured to perform the techniques related to communications between the AP and unassociated stations as described herein (see, e.g.,FIGS. 5-20).

In accordance with the present disclosure, AP105may include a memory330, one or more processors303and a transceiver306. The memory330, the one or more processors303and the transceiver306may communicate internally via a bus311. In some examples, the memory330and the one or more processors303may be part of the same hardware component (e.g., may be part of a same board, module, or integrated circuit). Alternatively, the memory330and the one or more processors303may be separate components that may act in conjunction with one another. The bus311may be a communication system that transfers data between multiple components and subcomponents of the AP105. In some examples, the one or more processors303may include any one or combination of modem processor, baseband processor, digital signal processor, and/or transmit processor. The one or more processors303may include a modem365. The AP105includes an unassociated station communications component340for carrying out one or more methods or procedures described herein in connection with an AP. The unassociated station communications component340may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in a memory (e.g., a computer-readable storage medium). For example, the unassociated station communications component340may be implemented by the processor303executing instructions stored on memory330.

In some examples, the memory330may be configured for storing data that is used in connection with local applications, and/or in connection with the unassociated station communications component340and/or one or more of any subcomponents being executed by the one or more processors303. Memory330can include any type of computer-readable medium usable by a computer or processor303, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory330may be a computer-readable storage medium (e.g., a non-transitory medium) that stores computer-executable code. The computer-executable code may define one or more operations or functions of the unassociated station communications component340and/or one or more of any subcomponents, and/or data associated therewith. The computer-executable code may define these one or more operations or functions when AP105is using processor303to execute the unassociated station communications component340and/or one or more of any subcomponents. In some examples, the AP105may further include the transceiver306for transmitting and/or receiving one or more data and control signals (e.g., messages) to/from a STA. For example, the AP105may transmit trigger frames, probe responses, broadcast probe responses, beacons, Fast Initial Link Setup (FILS) discovery frames, or other data or control frames. The transceiver306may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in a memory (e.g., a computer-readable storage medium). The transceiver306may include one or more radios, including a radio307comprising a transmitter308and a receiver315. The radio307may utilize one or more antennas302(e.g., antennas302-a, . . . ,302-n) for transmitting signals to and receiving signals from a plurality of STAs. The receiver315may include one or more components that form a receiving chain and the transmitter308may include one or more components that form a transmitting chain.

The unassociated station communications component340may be configured to perform, alone or in combination with other components of the AP105, at least any AP-side functions described in connection with the flow diagrams ofFIGS. 5-11andFIGS. 18-19.

FIG. 4illustrates an example wireless communication system400similar to the wireless communication system300inFIG. 3. One or more of the STAs115may be configured to participate in the communication characteristic signaling process described herein.

In accordance with the present disclosure, a STA115may include a memory430, one or more processors403and a transceiver406. The memory430, the one or more processors403and the transceiver406may communicate internally via a bus411. In some examples, the memory430and the one or more processors403may be part of the same hardware component (e.g., may be part of a same board, module, or integrated circuit). Alternatively, the memory430and the one or more processors403may be separate components that may act in conjunction with one another. The bus411may be a communication system that transfers data between multiple components and subcomponents of the STA115. In some examples, the one or more processors403may include any one or combination of modem processor, baseband processor, digital signal processor, and/or transmit processor. The one or more processors403may include a modem465. The STA115includes an unassociated station communications component440for carrying out one or more methods or procedures described herein in connection with a STA. The unassociated station communications component440may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in a memory (e.g., a computer-readable storage medium). For example, the unassociated station communications component440may be implemented by the processor403executing instructions stored on memory430.

In some examples, the memory430may be configured for storing data that is used in connection with local applications, and/or in connection with the unassociated station communications component440and/or one or more of any subcomponents being executed by the one or more processors403. Memory430can include any type of computer-readable medium usable by a computer or processor403, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory430may be a computer-readable storage medium (e.g., a non-transitory medium) that stores computer-executable code. The computer-executable code may define one or more operations or functions of the unassociated station communications component440and/or one or more of any subcomponents, and/or data associated therewith. The computer-executable code may define these one or more operations or functions when STA115is using processor403to execute the unassociated station communications component440and/or one or more of any subcomponents. In some examples, the STA115may further include the transceiver406for transmitting and/or receiving one or more data and control signals (e.g., messages) to/from a STA. The transceiver406may comprise hardware, firmware, and/or software and may be configured to execute code or perform instructions stored in a memory (e.g., a computer-readable storage medium). The transceiver406may include multiple radios that enable the STA115to operate as a multi-mode device or client. In this example, the transceiver406may include a first radio407having a transmitter (TX)408and a receiver (RX)409, and a second radio415having a TX416and a RX417. The first radio407may be a WLAN or Wi-Fi radio and the second radio415may be a non-WLAN system or non-Wi-Fi system radio (e.g., an LAA radio, an LTE-U radio).

Each of the first radio407and the second radio415may utilize one or more antennas402(e.g., antennas402-a, . . . ,402-n) for transmitting signals to and receiving signals from an AP. The receivers409and417may include one or more components that form a receiving chain, and the transmitters408and416may include one or more components that form a transmitting chain.

The unassociated station communications component440may be configured to perform, alone or in combination with other components of the STA115, at least the STA-side functions described in connection with the flow diagrams ofFIGS. 5-11andFIGS. 18-19.

Referring toFIGS. 5-11andFIGS. 18-19, examples of one or more operations related to the AP105(FIG. 3) and the STA115(FIG. 4) are described with reference to one or more methods and one or more components. Although the operations described below are presented in a particular order and/or as being performed by an example component, it should be understood that the ordering of the actions and the components performing the actions may be varied, depending on the implementation. Moreover, it should be understood that the following actions may be performed by a specially-programmed processor, a processor executing specially-programmed software or computer-readable media, or by any other combination of a hardware component and/or a software component specially configured for performing the described actions or components. For example, the various steps shown inFIGS. 5-11andFIGS. 18-19may be performed by a processor (e.g., processor303for AP-side functions or processor403for STA-side functions) coupled with memory (e.g., memory330for AP-side functions or memory430for STA-side functions) that stores instructions executable by the processor to perform the described action. Other STA or AP sub-components may also be involved in each step, such as transceivers and antennas for any receive and/or transmit steps. Also, any steps described as being performed by an AP may alternatively be performed by a STA, such as a STA operating in an AP mode or in a STA-to-STA direct communication mode. Similarly, any steps described as being performed by a STA may alternatively be performed by an AP, such as an AP communicating with other APs or STAs.

FIG. 5is a flow diagram illustrating an example of a process500for communicating with multiple different stations via an aggregated data unit (e.g., an A-MPDU), in accordance with various aspects of the present disclosure. In process500, a wireless communication device, such as an AP (for responding to multiple STAs that sent trigger-based uplink messages) or a STA (for responding to other STAs and/or APs that sent trigger-based messages) generates a frame that includes an aggregated data unit. Note that for the remainder of the description of this flow diagram, an AP (e.g., AP105ofFIG. 3) will be described as the wireless communication device sending the frame that includes the aggregated data unit, although the frame may be generated by a STA (e.g., STA115ofFIG. 4) in other implementations.

In some implementations, process500begins at a point in the sequence when the AP has already (1) sent a trigger frame to multiple unassociated STAs allocating one or more RUs for random access communications; and (2) received multiple trigger-based messages from multiple unassociated STAs. Thus, process500starts when the AP determines that it will send a downlink response to the multiple trigger-based messages. At block502, the AP generates a frame to respond to the multiple trigger-based messages from multiple unassociated STAs. Other implementations may use the techniques ofFIG. 5in other contexts. In the implementation ofFIG. 5, the AP may determine that it will respond to the multiple STAs in a single downlink MU PPDU.

FIG. 12illustrates one example of an MU PPDU1202that may be used by the AP in process500to transmit multiple responses to the multiple received trigger-based messages from multiple unassociated STAs. The MU PPDU1202includes a header1204. The header1204includes a number of different header fields, including header fields that provide an indication of the recipient of various data units included within the MU PPDU1202or an indication of the type of use (e.g., a broadcast to unassociated stations, a broadcast to associated stations, etc.) of a specific RU that will be used for a data unit included within the MU PPDU1202. For example, the header1204may include an indication1206regarding the recipient or type of use of RU1210and an indication1208regarding the recipient or type of use of RU1212.

The indications1206and1208may be located in a station identification portion of the header1204(e.g., a STA ID field). As a first example, when the AP sets the STA ID field to a value of 0, the AP is indicating broadcast (e.g., multi-recipient) communications with STAs that are already associated with the AP. As a second example, when the AP sets the STA ID field to a value of 2045, the AP is indicating broadcast (e.g., multi-recipient) communications with STAs that are unassociated with the AP. Although the value STA ID=2045 is used herein to indicate a situation where at least one resource unit is allocated for random access communications by STAs that are unassociated with the AP, values other than 2045 may instead be designated to indicate this situation in other implementations (such as if the IEEE 802.11ax standard, or later standards, changes which value signals this type of allocation). In a third example, when the AP sets the STA ID field to a specific value associated with a specific station, the AP is directing the communication to that specific station.

The MU PPDU1202may include multiple different frames to be carried on RUs. In the example ofFIG. 12, the MU PPDU1202includes a first A-MPDU1214to be carried on RU1210. Inside of the A-MPDU1214are multiple MPDUs1216,1218, and1220. The MPDUs1216,1218, and1220each include a recipient address (RA) field1222,1224, and1226that indicates the intended recipient of the MPDU. The MU PPDU1202may also contain other frames. For example, the MU PPDU1202may also include a frame, such as an A-MPDU or MPDU, to be carried on RU1212(although this additional frame is not shown inFIG. 12). The MU PPDU may also contain one or more other frames (not shown) to be carried on or more other RUs (not shown).

Returning to block502ofFIG. 5, the AP generates a frame that includes at least one A-MPDU that will be designated to communicate with multiple unassociated STAs (see, e.g., A-MPDU1214ofFIG. 12). In this situation, the AP will set the STA ID indication1206to a special value (e.g., 2045) that indicates broadcast communication on RU1210with unassociated STAs. The RU1210will then be used to carry the A-MPDU1214to communicate with the multiple unassociated STAs. At block504, the AP will set the RA field1222in a first MPDU1216of the A-MPDU1214to a first value that identifies a first STA that sent an uplink trigger-based message to the AP. At block506, the AP will set the RA field1224in a second MPDU1218of the A-MPDU1214to a second value, different than the first value, that identifies a second STA that sent an uplink trigger-based message to the AP. The AP may also set the RA field for one or more other MPDUs of the A-MPDU1214to address other STAs, such as the RA field1226in the MPDU1220ofFIG. 12. This implementation may be based on an exception to the current rules (see section 9.7.3 of the 802.11-2016 standard that “[a]ll of the MPDUs within an A-MPDU are addressed to the same RA”) that would allow the AP to address different MPDUs within an A-MPDU to different STAs. This exception may be triggered for case where the STA ID for the RU is set to a special value (e.g., 2045) that indicates broadcast communications with unassociated STAs.

At block508, the AP allocates one or more resource units to enable the STAs that will receive the messages included in the MPDUs1216,1218, and1220to send an uplink response message. The uplink response message may be an acknowledgement message acknowledging that the downlink MPDU was successfully received.

In a first implementation to allocate an RU for the uplink response message, the AP may include a triggered response scheduling (TRS) control field (which also may be referred to as an uplink multi-user response scheduling (UMRS) control field) of the MPDU to assign an RU to the STA to send an immediate response frame after receipt of the MPDU. For example, the TRS control field (or the UMRS control field) may be in the high efficiency (HE) control field of the MPDU.FIG. 13illustrates one example of the A-MPDU1214ofFIG. 12that includes an optional TRS control field in one or more of the MPDUs of the A-MPDU. Specifically,FIG. 13illustrates: (1) a TRS control field1302in MPDU1216to allocate an RU for an uplink response message from the STA identified in the RA field1222of the MPDU1216; (2) a TRS control field1304in MPDU1218to allocate an RU for an uplink response message from the STA identified in the RA field1224of the MPDU1218; and (3) a TRS control field1306in MPDU1220to allocate an RU for an uplink response message from the STA identified in the RA field1226of the MPDU1220.FIG. 17an example of an TRS control field1700usable within each of the MPDUs of the A-MPDU1214to allocate an RU for each receiving STA. In some implementations, the TRS control field1700may include a high efficiency (HE) trigger-based (TB) PPDU length field1702, an RU allocation field1704, a DL Tx power field1706, an UL target received signal strength indicator (RSSI)1708, an UL modulation coding scheme (MCS) field1710, and reserved field(s)1712. This implementation may be based on an exception to the general rule that all TRS control fields within an A-MPDU will have identical content. Rather, to enable this implementation, TRS control fields1302,1304, and1306will have different content to allocate potentially different RUs to potentially different STAs.

In a second implementation to allocate an RU for the uplink response message, the AP may aggregate one or more trigger frames within the A-MPDU that carries the MPDUs for the multiple unassociated STAs. Each trigger frame may allocate an RU for each STA to send its uplink response frame (e.g., acknowledgement of receipt of an MPDU) to the AP.FIG. 14illustrates one example of the A-MPDU1214ofFIG. 12that includes one or more trigger frames1402,1404, and1406to allocate future uplink resources for the STAs that receive the A-MPDU1214. Specifically,FIG. 14illustrates: (1) a trigger frame1402positioned directly after MPDU1216to allocate an RU for an uplink response message from the STA identified in the RA field1222of the MPDU1216; (2) a trigger frame1404positioned directly after MPDU1218to allocate an RU for an uplink response message from the STA identified in the RA field1222of the MPDU1218; and (3) a trigger frame1406positioned directly after MPDU1220to allocate an RU for an uplink response message from the STA identified in the RA field1222of the MPDU1220.FIG. 2an example of trigger frame200usable within the A-MPDU1214to allocate an RU for a STA that receives the A-MPDU. This implementation may be based on an exception to the general rule that all trigger frames within an A-MPDU will have identical content. Rather, to enable this implementation, trigger frames1402,1404, and1406will have different content to allocate potentially different RUs to potentially different STAs.

In some implementations, unassociated STAs do not have an association identification (AID) assigned to them for communications with the AP (because they are currently unassociated). In these implementations, the AP may not be able to use a single trigger frame in the A-MPDU1214to assign RUs for all the STAs in the transaction. Thus, the implementation ofFIG. 14solves this potential issue by positioning the trigger frames1402,1404, and1406at locations within the A-MPDU1214that would allow a receiving STA to determine the intended recipient of the trigger frame by proximity to other frames that do identify a specific STA. For example, a receiving STA would process MPDU1216and determine that the RA field1222indicates that MPDU1216is intended for a specific STA. Based on the trigger frame1402being the next frame in the sequence of frames within the A-MPDU1214, the STA can then assume that any RU allocated by the trigger frame1402will be for the STA that is identified in the RA field1222. For example, the receiving STA can ignore the value of the association ID field (e.g., an AID12 subfield) of the trigger frame and instead rely on identifying the intended recipient based on the proximity to the MPDU. Similar assumptions may be made for the trigger frame1404based on its position relative to MPDU1218and trigger frame1406based on its position relative to MPDU1220. Alternatively, instead of using an assumed intended recipient of the trigger frame based on position of the trigger frame relative to other frames, the trigger frame could include an association ID field (e.g., an AID12 subfield) with a value that signals an association with a specific wireless communication device or a group of wireless communication devices.

Placing a trigger frame immediately after the MPDU that is associated with the trigger frame (e.g., the trigger frame is allocating an RU for the STA addressed in the MPDU to respond to the MPDU), rather than at the end of the sequence of frames of the A-MPDU may also allow partial A-MPDU recovery in the event that a portion of the A-MPDU was lost, corrupted, or otherwise not received by the intended recipient. For example, if the A-MPDU1214ofFIG. 14was corrupted at a position between the trigger frame1402and the MPDU1218, then the STA associated with the MPDU1216and the trigger frame1402may still be able to process and respond to the AP that sent the MPDU1216and the trigger frame1402. If all the trigger frames1402,1404, and1406in this example would have been placed at the end of the frame sequence in the A-MPDU1214, then this partial recovery may not have been available because the STA would not have had an allocated RU to enable an acknowledgement of at least this information. The STA would not have been able to send an acknowledgement and the AP would assume that all information of the A-MPDU was lost. It may then try to resend the entirely of the A-MPDU1214again despite successful reception of the MPDU1216. In the example where the A-MPDU was corrupted at a position between the trigger frame1402and the MPDU1218, then the STA associated with the MPDU1218and the trigger frame1404, and the STA associated with the MPDU1220and the trigger frame1406, will be unable to decode and process the corrupted/lost portion of the A-MPDU1214and thus may determine that their uplink transmission was not successful. If the downlink response does not arrive in a retransmission of the corrupted/lost A-MPDU, then STAs may eventually try to initiate future random access communications with the AP in future RUs allocated for communications with unassociated STAs.

Returning toFIG. 5, at block510, the AP outputs the frame, which includes the A-MPDU1214, for transmission to multiple unassociated STAs. In one implementation, a microchip or integrated circuit (e.g., a modem chip) that is a sub-component of the AP may output the frame for eventual physical transmission over the air through other sub-components of the AP, such as a radio frequency transmitter and an antenna of the AP (and other radio frequency transmission components of the AP). In another implementation, the AP itself as an entire unit outputs the frame for transmission by formatting the message data and generating the physical over-the-air transmission of the data of the frame to be received by multiple STAs.

FIG. 6is a flow diagram illustrating an example of a process600for processing an incoming aggregated data unit that communicates with multiple different stations. In process600, a wireless communication device may receive a frame that includes an aggregated data unit from a second device. The wireless communication device may be a STA (when receiving the frame from an AP or another STA) or an AP (when receiving the frame from a STA or another AP). Note that for the remainder of the description of this flow diagram, a STA (e.g., STA115ofFIG. 4) will be described as the wireless communication device receiving and processing the frame, although the frame may be received by an AP (e.g., AP105ofFIG. 3) in other implementations.

In some implementations, process600begins at a point in the sequence when the STA has already (1) received a trigger frame from an AP allocating one or more RUs for random access communications; and (2) sent a trigger-based message to the AP on the allocated RU in response to the trigger frame. Thus, process500starts when the STA receives a downlink response to the trigger-based message sent by the STA. Other implementations may use the techniques ofFIG. 6in other contexts. In one implementation, the process600ofFIG. 6is the station-side counterpart to the AP-side process500ofFIG. 5. For example, in process600the actions are performed by a STA receiving and processing an incoming MU PPDU formatted by an AP according to the process500ofFIG. 5.

At block602, a STA receives a frame from another device, such as an AP. The frame may be structured the same or similar to the MU PPDU1202ofFIG. 12(as optionally modified in some implementations by the various additional options ofFIGS. 13 and 14). The MU PPDU1202includes at least one A-MPDU (see A-MPDU1214). A-MPDU1214includes multiple MPDUs1216,1218, and1220, which include RA fields1222,1224, and1226respectively.

At block604, the STA decodes a first MPDU1216in the received A-MPDU1214and identifies the RA field1222in the first MPDU1216. At block606, the STA analyzes the value of the RA field1222and determines that the MPDU1216is not intended for the receiving STA. For example, the RA field1222may identify a different STA that also sent a message to the AP in response to the AP's trigger frame that allocated an RU for random access communications by unassociated STAs. If the STA was to follow current section 9.7.3 of the 802.11-2016 standard (stating that “[a]ll of the MPDUs within an A-MPDU are addressed to the same RA”), the STA could skip processing the remaining MPDUs of the A-MPDU1214because all the MPDUs of the A-MPDU would be expected to be addressed to the same STA. However, when the AP has included MPDUs directed to different STAs within a single A-MPDU (as done in the process500ofFIG. 5), the receiving STA may then continue to process additional MPDUs of the A-MPDU even when the first MPDU is not addressed to this STA. Thus, at block608, the STA continues decoding MPDUs and moves to decode a second MPDU1218and identify the RA field1224of the second MPDU1218.

At block610, the STA determines that the MPDU1218is intended for the receiving STA. For example, the STA may determine that the RA field1224includes a value that identifies the receiving STA as the intended recipient. At block612, the STA processes the MPDU1218and generates an uplink response frame, such as an acknowledgement confirming receipt of the MPDU1218. The STA may also decode any additional MPDUs within the A-MPDU1214, such as MPDU1220and determine if MPDU1220is intended for the STA. At block614, the STA identifies an RU allocated for the STA to send the uplink response frame, and then outputs the uplink response frame for transmission to the AP. The STA may identify an RU allocation by processing a TRS control field in the MPDU1218(see TRS control field1304ofFIG. 13) or by processing a trigger frame associated with the MPDU1218(see trigger frame1404ofFIG. 14), as discussed more fully above in connection with block508ofFIG. 5.

FIG. 7is a flow diagram illustrating an example of a process700for communicating with multiple different stations via an aggregated data unit (e.g., an A-MPDU), in accordance with various aspects of the present disclosure. In process700, a wireless communication device, such as an AP (for responding to other STAs and/or APs that sent trigger-based messages) or a STA (for responding to other STAs and/or APs that sent trigger-based messages) generates a frame that includes an aggregated data unit. Note that for the remainder of the description of this flow diagram, an AP (e.g., AP105ofFIG. 3) will be described as the wireless communication device sending the frame that includes the aggregated data unit, although the frame may be generated by a STA (e.g., STA115ofFIG. 4) in other implementations.

In some implementations, process700begins at a point in the sequence when the AP has already (1) sent a trigger frame to multiple unassociated STAs allocating one or more RUs for random access communications; and (2) received multiple trigger-based messages from multiple unassociated STAs. Thus, process700starts when the AP determines that it will send a downlink response to the multiple trigger-based messages. At block702, the AP generates a frame to respond to the multiple trigger-based messages from multiple unassociated STAs. Other implementations may use the techniques ofFIG. 7in other contexts. In the implementation ofFIG. 7, the AP may determine that it will respond to the multiple STAs in a single downlink MU PPDU.

At block702, the AP generates a frame that includes at least one A-MPDU that will be designated to communicate with multiple unassociated STAs (see, e.g., A-MPDU1214ofFIG. 12). In this situation, the AP will set the STA ID indication1206to a value (e.g., 2045) that indicates broadcast communication on RU1210with unassociated STAs. The RU1210will then be used to carry the A-MPDU1214to communicate with the multiple unassociated STAs.

At block704, the AP will set the RA fields in multiple MPDUs of the A-MPDU1214to a same value. For example, the AP may set the RA fields1222,1224, and1226to be the same value, such as a value that indicates a broadcast communication type (e.g., a multi-recipient communication type). In this implementation, because each of the RA fields1222,1224, and1226will not identify a unique STA as the recipient of the MPDU, the AP may use a different portion of the MPDU to identify the specific intended recipient. As one example, the AP may use an address4field to identify a single intended recipient of an MPDU (as described inFIGS. 7, 8, 13, and 16). As another example, the AP may use one of the BA fields (such as the BA information field) in a Multi-STA BlockAck (BA) frame type to identify one or more intended recipients of an MPDU (as described inFIGS. 18, 19, and 20).FIG. 16illustrates one example of a media access control (MAC) frame format that includes an address1field1606, an address4field1614, and other fields (including other address fields). In some implementations, the additional fields may include a frame control field1602, a duration/ID field1604, an address2field1608, an address3field1610, a sequence control field1612, a QoS control field1616, a HT control field1618, a frame body1620, and an FCS1622. In some implementations, the HT control field1618may include an A-Control subfield that includes the TRS control field1700shown inFIG. 17. In one implementation for process700, the AP may use the address1field1606to be the RA field that carries a value common to all MPDUs within one A-MPDU, and may use the address4field1614to carry the unique address of the intended STA recipient. This implementation may be based on an exception to the general practice that the address4field is not used in many types of communications. Rather, to enable this implementation, the address4field will be enabled for situations where an MPDU is carried in an A-MPDU for an RU with a station identification (STA ID) field indicating communication with unassociated STAs.

FIG. 13illustrates one example of the A-MPDU1214ofFIG. 12that includes an optional address4field (e.g., in the format shown inFIG. 16) in one or more of the MPDUs of the A-MPDU. Specifically,FIG. 13illustrates: (1) an address4field1308in MPDU1216to identify a first STA as the intended recipient of MPDU1216; (2) an address4field1310in MPDU1216to identify a second STA as the intended recipient of MPDU1218; and (3) an address4field1312in MPDU1220to identify a third STA as the intended recipient of MPDU1220.

At block706ofFIG. 7, the AP sets the address4field1308(ofFIG. 13) to a first value that identifies a first STA that sent an uplink trigger-based message to the AP. At block708, sets the address4field1310(ofFIG. 13) to a second value, different than the first value, that identifies a second STA that sent an uplink trigger-based message to the AP. The AP may also set the address4field for one or more other MPDUs of the A-MPDU1214to address other STAs, such as the address4field1312in the MPDU1220ofFIG. 13.

At block710, the AP allocates one or more resource units to enable the STAs that will receive the messages included in the MPDUs1216,1218, and1220to send an uplink response message. The operations of block710are described above in connection with block508(including with reference to the options involving the TRS control filed and/or aggregating trigger frames with the MPDUs of the A-MPDU1214). At block712, the AP outputs the frame, which includes the A-MPDU1214, for transmission to multiple unassociated STAs, as described above in connection with block510.

FIG. 8is a flow diagram illustrating an example of a process800for processing an incoming aggregated data unit that communicates with multiple different stations. In process600, a wireless communication device may receive a frame that includes an aggregated data unit from a second device. The wireless communication device may be a STA (when receiving the frame from an AP or another STA) or an AP (when receiving the frame from a STA or another AP). Note that for the remainder of the description of this flow diagram, a STA (e.g., STA115ofFIG. 4) will be described as the wireless communication device receiving and processing the frame, although the frame may be received by an AP (e.g., AP105ofFIG. 3) in other implementations.

In some implementations, process800begins at a point in the sequence when the STA has already (1) received a trigger frame from an AP allocating one or more RUs for random access communications; and (2) sent a trigger-based message to the AP on the allocated RU in response to the trigger frame. Thus, process800starts when the STA receives a downlink response to the trigger-based message sent by the STA. Other implementations may use the techniques ofFIG. 8in other contexts. In one implementation, the process800ofFIG. 8is the station-side counterpart to the AP-side process700ofFIG. 7. For example, in process800the actions are performed by a STA receiving and processing an incoming MU PPDU formatted by an AP according to the process700ofFIG. 7.

At block802, a STA receives a frame from another device, such as an AP. The frame may be structured the same or similar to the MU PPDU1202ofFIG. 12(as optionally modified in some implementations by the various additional options ofFIGS. 13 and 14). The MU PPDU1202includes at least one A-MPDU (see A-MPDU1214). A-MPDU1214includes multiple MPDUs1216,1218, and1220, which include RA fields1222,1224, and1226respectively. For the implementation of process800, the MPDUs1216,1218, and1220also include address4fields1308,1310, and1312(seeFIG. 13).

At block804, the STA decodes a first MPDU1216in the received A-MPDU1214and identifies the RA field1222in the first MPDU1216. At block806, the STA analyzes the value of the RA field1222and determines that the RA field1222includes a special value (such as a value that indicates a broadcast communication type or a multiple recipient communication type). In some implementations, this same value may be included in the RA fields for all the MPDUs in the A-MPDU1214. As an alternative to analyzing the RA field1222at block806, the STA may determine that the A-MPDU1214is carried in an RU allocated for communication with unassociated stations (in which case the STA may ignore the RA field in some implementations). In response to identifying the special (e.g., broadcast) value in the RA field1222or that the A-MPDU1214is carried in an RU allocated for communication with unassociated stations, the STA knows to analyze an address4field1308in the first MPDU1216(seeFIG. 13) instead of the RA field1222to determine whether the MPDU1216is addressed to this specific STA. At block808, the STA analyzes the address4field1308and at block810determines that the address4field1308contains a value that identifies this specific STA. In the example of process800, the first MPDU1216included an address4field1308that identifies the receiving STA. However, in other examples, the STA may find a matching address4field in a later MPDU or no MPDU at all. Thus, the STA may continue processing RA and address4fields of subsequent MPDUs similar to the processing at blocks804,806, and808.

At block812, the STA processes the MPDU1216and generates an uplink response frame, such as an acknowledgement confirming receipt of the MPDU1216. At block814, the STA identifies an RU allocated for the STA to send the uplink response frame, and then outputs the uplink response frame for transmission to the AP. The STA may identify an RU allocation by processing a TRS control field in the MPDU1216(see TRS control field1302ofFIG. 13) or by processing a trigger frame associated with the MPDU1216(see trigger frame1402ofFIG. 14), as discussed more fully above in connection with block508ofFIG. 5.

FIG. 9is a flow diagram illustrating an example of a process900for sending multiple frames related to random access communications with multiple unassociated devices, in accordance with various aspects of the present disclosure. In process900, a wireless communication device, such as an AP (for responding to multiple STAs that sent trigger-based uplink messages) or a STA (for responding to other STAs and/or APs that sent trigger-based messages) generates multiple frames related to random access communications with multiple unassociated devices. Note that for the remainder of the description of this flow diagram, an AP (e.g., AP105ofFIG. 3) will be described as the wireless communication device sending the multiple frames related to random access communications with multiple unassociated stations, although the frame may be generated by a STA (e.g., STA115ofFIG. 4) in other implementations.

At block902, the AP outputs a trigger frame (e.g., the trigger frame200ofFIG. 2) that allocates one or more RUs for random access communications by one or more STAs that are currently unassociated with the AP. Random access communications in one implementation differ from directed communications in that any STA within a designated category (e.g., all associated STAs or all unassociated STAs) may access an allocated RU in random access communication mode as opposed to only a specific STA directed by the AP to use the RU in directed communication mode. When an RU is allocated for random access communications by unassociated STAs, any unassociated STA may contend for the allocated RU. The AP may customize the fields of the trigger frame to indicate that it allocates one or more RUs for random access communications by one or more STAs that are currently unassociated with the AP. In one implementation, the AP may signal the random access RU allocation in a user information field of the trigger frame (e.g., user information field212of trigger frame200ofFIG. 2). The user information field212may include multiple subfields such as an AID12 subfield and an RU allocation subfield (among other subfields). In one implementation, the AP uses the AID12 subfield to signal that the trigger frame includes one or more RUs (as identified by the RU allocation subfield of the user information field212) allocated for random access communications by one or more STAs that are currently unassociated with the AP. The AID12 subfield carries the 12 least significant bits of the association identification (AID) of the STA for which the user information field of the trigger frame is intended. When the AP sets the AID12 subfield to a value of 2045 (or any other designated value), the AP is indicating that the user information field is allocated for random access communications by STAs that are unassociated with the AP.

At block904, the AP receives multiple uplink messages sent in response to the trigger frame output at block902. A STA that receives the trigger frame from block902may send a trigger-based PPDU in response to the trigger frame on the allocated RU (e.g., it may use the subcarriers of the allocated RU to transmit its response frame). At block906, the AP determines that the received uplink messages require downlink responses. For example, if the STAs send probe requests to the AP, then the AP may determine that it will respond with a probe response back to each of the requesting STAs.

When multiple STAs use the opportunity to communicate with the AP, the AP may need to coordinate multiple response frames responses back to the STAs. As discussed above in connection withFIGS. 5 and 7, there are some implementations that allow a single MU frame to communicate response messages back to multiple STAs. However, these implementations may be enabled by a standard change that allows the RA fields of different MPDUs in an A-MPDU to have different values (seeFIG. 5) or by use of extra address field, such as an address4field (seeFIG. 7). Some other implementations may not desire these types of changes. These implementations may instead break up the responses into multiple different transmission opportunities instead of trying to package all responses into a single MU frame.

At block908, the AP generates an MU frame. When the AP has multiple responses due to multiple different STAs who sent messages to the AP on the RU allocated in the trigger frame for communications by unassociated STAs, the AP may elect to include at least one of the responses in the MU frame. The AP may then send the other responses in different transmission opportunities (either earlier or later than the transmission opportunity that was used for the MU frame). The other responses may be separate single-user (SU) transmissions or may be separate MU transmissions. By including at least one response to an unassociated STA into an MU frame that contains other frames targeted to other STAs, the AP can gain some transmission efficiency relative to keeping all downlink messages intended for unassociated STAs for separate later transmission opportunities.

FIG. 15is one example of an MU frame followed by a second frame (which could either be MU or SU).FIG. 15shows an example of the MU frame1202(which is shown as a simplified version of the frame shown inFIG. 12) where the A-MPDU1214includes an MPDU1216intended for one of the unassociated STAs that sent a trigger-based message to the AP. The MPDU1216includes an RA field1222that identifies the unassociated STA that is the intended recipient of the MPDU1216. The AP may also allocate an RU for the STA addressed by the RA field1222to send a response frame back to the AP (e.g., to acknowledge receipt of the MPDU1216). The AP may either include a TRS control field1302in the MPDU1216or may aggregate a trigger frame1402with the MPDU1216to allocate the RU for the future uplink response. The MU frame1202may also include other frames (not shown) intended for other STAs. At block910, the AP outputs the MU PPDU1202for transmission to the STA addressed by the MPDU1216and any other STA addressed by other frames in the MU PPDU1202.

At block912ofFIG. 9, the AP generates a second frame to be transmitted in a second transmission opportunity to carry one or more other responses to unassociated STAs that sent trigger-based messages to the AP.FIG. 15shows an example of a second frame1502that is used to carry the second MPDU1218that is intended for an unassociated STA. The second frame1502includes an indication1504regarding the recipient or type of use of the RU that will carry the MPDU1218. In one implementation, the indication1504may be located in a station identification portion of a frame header (e.g., a STA ID field). When the AP sets the STA ID field to a value of 2045 (or any other designated value), the AP is indicating broadcast communications with STAs that are unassociated with the AP. The second MPDU1218may include an RA field1224that identifies the intended unassociated recipient STA. The AP may also allocate an RU for the STA addressed by the RA field1224to send a response frame back to the AP (e.g., to acknowledge receipt of the MPDU1216). The AP may either include a TRS control field1304in the MPDU1218or may aggregate a trigger frame1404with the MPDU1218to allocate the RU for the future uplink response. Returning toFIG. 9, at block914, the AP outputs the second frame1502for transmission to the STA addressed by the MPDU1218.

FIG. 10is a flow diagram illustrating an example of a process1000for processing multiple frames related to random access communications. In process1000, a wireless communication device may receive multiple frames related to random access communications from a second device. The wireless communication device may be a STA (when receiving the frames from an AP or another STA) or an AP (when receiving the frames from a STA or another AP). Note that for the remainder of the description of this flow diagram, a STA (e.g., STA115ofFIG. 4) will be described as the wireless communication device receiving and processing the multiple frames related to random access communications, although the frames may be received by an AP (e.g., AP105ofFIG. 3) in other implementations. In one implementation, the process1000ofFIG. 10is the STA-side counterpart to the AP-side process900ofFIG. 9. For example, in process1000the actions are performed by a STA receiving and processing an incoming MU PPDU, and at least a second frame, all formatted by an AP according to the process900ofFIG. 9.

At block1002, a STA receives a trigger frame that allocates one or more RUs for communications by unassociated STAs. The trigger frame may be formatted as discussed above in connection with block902(FIG. 9). At block1004, the STA outputs a trigger-based response to the AP (e.g., a probe response or other management frame) on the RU allocated by the trigger frame. At block1006, the STA receives an MU frame (e.g., MU PPDU1202ofFIG. 15) sent in a first transmission opportunity after the AP receives the uplink trigger-based message from the STA. The MU frame may be formatted as discussed above in connection with block908. At block1008, the STA determines that the MU frame does not contain a response to the trigger based message the STA previously sent to the AP in response to the trigger frame. For example, the STA may analyze the indication1206, the RA field1222, or both, and determine that the A-MPDU1214is not intended for the STA. The STA may also analyze other RUs used by the MU PPDU1202and determine that those RUs also do not contain a response for the STA.

At block1010, the STA may receive a second frame (e.g., the frame1502ofFIG. 15) sent in a second (or subsequent) transmission opportunity after the AP receives the uplink trigger-based message from the STA. The second frame may be formatted as discussed above in connection with block912. At block1012, the STA determines that the second frame does contain a response to the trigger based message the STA previously sent to the AP in response to the trigger frame. For example, the STA may analyze the indication1504, the RA field1224, or both, and determine that the MPDU1218is intended for the STA. At block1014, the STA fully processes the second frame because it is intended for the receiving frame, identifies an RU allocation for an uplink response message (e.g., an acknowledgment of receipt of the MPDU1218) by using an RU allocation signaled in TRS control field1304or trigger frame1404(seeFIG. 15), and outputs the uplink response message for transmission to the AP on the allocated RU.

As discussed above, there are multiple different solutions for ways to address and communicate with unassociated STAs. As a first example, the solutions ofFIGS. 5 and 6relate to using different values in the RA fields of different MPDUs to differentiate the intended recipients. As a second example, the solutions ofFIGS. 7 and 8relate to using different values in the address4fields of different MPDUs to differentiate the intended recipients. As a third example, the solutions ofFIGS. 9 and 10relate to using multiple frames in multiple different transmission opportunities to differentiate the intended recipients. The first and second examples may be enabled by an exception to the IEEE 802.11 baseline standard processing (as discussed above). Thus, these solutions may be conditionally enabled by a capability advertisement sent by the STAs to the AP, such as in a bit of the high efficiency (HE) capabilities element. The capability advertisement may indicate whether the STA can support multi-destination receiving in a broadcast RU. For example, STAs may advertise that they can support receiving A-MPDUs that have MPDUs with different RA values or can support receiving MPDUs where the intended recipient is indicated in the address4field. An AP may then use this indication to decide which STAs to include in such multi-destination A-MPDUs. For STAs that do not signal this capability, the AP may use the example solution ofFIGS. 9 and 10or may communicate with SU transmissions.

FIG. 11is a flow diagram illustrating an example of a process1100for determining whether to decode an incoming message related to random access communication. In process1100, a wireless communication device may receive a frame related to random access communications from a second device. The wireless communication device may be a STA (when receiving the frame from an AP or another STA) or an AP (when receiving the frame from a STA or another AP). Note that for the remainder of the description of this flow diagram, a STA (e.g., STA115ofFIG. 4) will be described as the wireless communication device receiving and processing the frame related to random access communications, although the frame may be received by an AP (e.g., AP105ofFIG. 3) in other implementations.

At block1102, a STA receives a trigger frame that allocates one or more RUs for communications by unassociated STAs. The trigger frame may be formatted as discussed above in connection with block902(FIG. 9). At block1104, the STA elects to not send a message back to the AP in response to the trigger frame. For example, the STA may not be interested in associating with this AP or discovering additional information about the AP. At block1106, the STA receives a frame from the AP (e.g., the device that sent the trigger frame). The frame may be sent in a next transmission opportunity after a response to the trigger frame would have been sent (if any was elected to be sent). The frame may be a downlink MU PPDU and include an indication that the frame contains information for one or more unassociated STAs. For example, the frame may include a value of 2045 (or any other designated broadcast special value) for the station identification (STA ID) field of the frame. The STA may decode at least a portion of the frame and determine that the frame is a response to an uplink message sent by a STA in response to the trigger frame. However, because the STA knows that it did not send any message to the AP in response to the trigger frame, the STA can determine on its own (e.g., without needing to find a specific address of a different STA in the message) that this message is not intended for this STA. Thus, at block1110, the STA may elect not to decode at least a portion of the frame thereby saving processing effort and/or battery power that would otherwise be used to process a frame that is not intended for the STA.

FIG. 18is a flow diagram illustrating an example of a process1800for communicating with one or more unassociated STAs via an aggregated data unit (e.g., an A-MPDU), in accordance with various aspects of the present disclosure. In process1800, a wireless communication device, such as an AP (for responding to other STAs and/or APs that sent trigger-based messages) or a STA (for responding to other STAs and/or APs that sent trigger-based messages) generates a first frame that includes an aggregated data unit. Note that for the remainder of the description of this flow diagram, an AP (e.g., AP105ofFIG. 3) will be described as the wireless communication device sending the first frame that includes the aggregated data unit, although the frame may be generated by a STA (e.g., STA115ofFIG. 4) in other implementations.

In some implementations, process1800begins at a point in the sequence when the AP has already (1) sent a trigger frame to multiple unassociated STAs allocating one or more RUs for random access communications; and (2) received multiple trigger-based messages from multiple unassociated STAs. Thus, process1800starts when the AP determines that it will send a downlink response to the multiple trigger-based messages. At block1802, the AP generates a frame to respond to the multiple trigger-based messages from multiple unassociated STAs. Other implementations may use the techniques ofFIG. 7in other contexts. In the implementation ofFIG. 7, the AP may determine that it will respond to the multiple STAs in a single downlink (DL) MU PPDU.

At block1802, the AP generates a first frame that includes at least a first A-MPDU that will be designated to communicate with multiple unassociated STAs. The first A-MPDU may include one or more MPDUs, and may set the STA ID indication to a value (e.g., 2045) that indicates the first frame is a broadcast communication with unassociated STAs. A RU may be used to carry the A-MPDU to communicate with the multiple unassociated STAs. In some implementations, the first frame may be a Multi-STA BlockAck (BA) frame type. In some implementations, the first frame (such as a BlockAck BA frame) may be included in an RU (such as a broadcast RU) of a DL MU PPDU having a STA ID field set to a value that indicates a broadcast communication with one or more unassociated wireless communication devices. For example, the STA ID field may be set to a value of 2045. In some implementations, the first frame may be included in the DL MU PPDU1202shown inFIG. 12, which may include the RU1210having the A-MPDU1214that may include one or more MPDUs (such as MPDU1216).

FIG. 20illustrates one example of a Multi-STA BA frame format that includes a BA information field having one or more RA subfields. In some implementations, the Multi-STA BA frame2000may include a frame control field2002, a duration field2004, an RA field2006, a TA field2008, a BA control field2010, one or more BA information field(s)2012, and an FCS field2014. The BA information field(s) may include one or more corresponding RA subfield(s)2025. In some implementations, the BA information field may include one or more AID/TID fields, and each AID/TID fields may include an RA subfield2025.

Returning toFIG. 18, at block1804, the AP sets a first RA field to a first value in a first MPDU of the one or more MPDUs in the first A-MPDU. For example, the AP may set the RA field2006of the Multi-STA BA frame2000to a broadcast address that indicates a broadcast communication type (e.g., a multi-recipient communication type).

At block1806, the AP (which may be referred to as a first wireless communication device) sets a first field in the first MPDU to a second value. In some implementations, the second value may represent an identifier of a first STA (which may be referred to as a second wireless communication device). For example, the AP may set a first RA subfield2025of the first field (such as a first BA information field2012) to a first address (such as a first MAC address) associated with the first STA. In some implementations, the first field may be a different field in the same or a different frame type. For example, as described above inFIGS. 7 and 8, the first field may be a first address4field of a MAC frame type, or, as described inFIGS. 5 and 6, the first field may be a first RA field.

In some implementations, the AP may set a second field in the first MPDU to a third value, different than the second value, that represents an identifier of a second STA (which may be referred to as a third wireless communication device). For example, the AP may set a second RA subfield2025of the second field (such as a second BA information field2012) to a second address (such as a second MAC address) associated with the second STA. In some implementations, the second field may be a different field in the same or a different MPDU in the same or a different frame type. For example, as described above inFIGS. 7 and 8, the second field may be a second address4field in a second MPDU of a MAC frame type, or, as described inFIGS. 5 and 6, the second field may be a second RA field in a second MPDU.

At block1808, the AP outputs the first frame for transmission to at least the first STA. The AP may broadcast the first frame to multiple STAs, such as the first STA and the second STA, when the BA information field of the first frame includes multiple RA subfields2025(such as the first and second RA subfields2025), as described herein in connection with block1806.

In some implementations, the first frame may be a unicast Multi-STA BA frame that may be directed to a single STA, such as the first STA. In a unicast Multi-STA BA frame, the first value of the first RA field may be the same as the second value of the first field of the first MPDU. For example, both the first RA and the first field of the first MPDU may be set to an address (such as a MAC address) associated with the first STA. In some implementations, the first RA field may be set to a broadcast address, and the first field of the first MPDU may be set to an address (such as a MAC address) associated with the first STA. In some implementations, the first frame (such as the unicast BlockAck BA frame described herein) may be included in an RU (such as a broadcast RU) of a DL MU PPDU having a STA ID field set to a value that indicates a broadcast communication with one or more unassociated wireless communication devices. For example, the STA ID field may be set to a value of 2045. In some implementations, the first frame may be included in the DL MU PPDU1202shown inFIG. 12, which may include the RU1210having the A-MPDU1214that may include one or more MPDUs (such as MPDU1216).

In some implementations, the first frame may be a response frame that is transmitted to each of one or more unassociated STAs (such as the first STA and the second STA). For example, the response frame may be a probe response frame, a (re)association response frame, or an authentication response frame. In some implementations, the AP may transmit the response frame after broadcasting a Multi-STA BA frame, such as the Multi-STA BA frame2000, to the one or more unassociated STAs. The AP may generate and output for transmission the response frame to each of the one or more unassociated STAs that previously communicated with the AP. For example, the AP may transmit a first response frame to the first STA (which may have previously responded to the AP's trigger frame), and a second response frame to the second STA (which may also have previously responded to the AP's trigger frame). In some implementations, instead of including a broadcast address as the first value in the first RA field, since the response frame may be directed to a single STA, the first RA field of the response frame may indicate a MAC address of the respective STA. In some implementations, the response frame may also include a TRS control field (such as the TRS control field described inFIG. 17). The TRS control field may allocate resources and provides response information to the respective STA so that the STA knows when and where to respond (such as sending an acknowledgement frame). For example, the TRS control field may allocate an RU for the respective STA to use for communications. The TRS control field also may specify a PPDU length, a transmission power, a target RSSI, and modulation coding scheme (MCS). In some implementations, the first frame (such as the response frame described herein) may be included in an RU (such as a broadcast RU) of a DL MU PPDU having a STA ID field set to a value that indicates a broadcast communication with one or more unassociated wireless communication devices. For example, the STA ID field may be set to a value of 2045. In some implementations, the first frame may be included in the DL MU PPDU1202shown inFIG. 12, which may include the RU1210having the A-MPDU1214that may include one or more MPDUs (such as MPDU1216).

In some implementations, the first frame may be directed to all unassociated STAs in the network, including at least the first STA. For example, the first frame may be a beacon frame, a probe response frame, or a FILS discovery frame. The first RA field in the first MPDU may be set to a broadcast address to indicate the frame is directed to all unassociated STAs in the network. In some implementations, the first frame (such as the beacon frame, probe response frame, or a FILS discovery frame described herein) may be included in an RU (such as a broadcast RU) of a DL MU PPDU having a STA ID field set to a value that indicates a broadcast communication with all unassociated wireless communication devices. For example, the STA ID field may be set to a value of 2045. In some implementations, the first frame may be included in the DL MU PPDU1202shown inFIG. 12, which may include the RU1210having the A-MPDU1214that may include one or more MPDUs (such as MPDU1216).

FIG. 19is a flow diagram illustrating an example of a process1900for processing an incoming aggregated data unit that communicates with one or more unassociated STAs. In process1900, a wireless communication device may receive a first frame that includes an aggregated data unit from a second device. The wireless communication device may be a STA (when receiving the frame from an AP or another STA) or an AP (when receiving the frame from a STA or another AP). Note that for the remainder of the description of this flow diagram, a STA (e.g., STA115ofFIG. 4) will be described as the wireless communication device receiving and processing the first frame, although the first frame may be received by an AP (e.g., AP105ofFIG. 3) in other implementations.

In some implementations, process1900begins at a point in the sequence when the STA has already (1) received a trigger frame from an AP allocating one or more RUs for random access communications; and (2) sent a trigger-based message to the AP on the allocated RU in response to the trigger frame. Thus, process1900starts when the STA receives a downlink response to the trigger-based message sent by the STA. Other implementations may use the techniques ofFIG. 19in other contexts. In one implementation, the process1900ofFIG. 19is the station-side counterpart to the AP-side process1800ofFIG. 18. For example, in process1900the actions are performed by a STA receiving and processing an incoming MU PPDU formatted by an AP according to the process1800ofFIG. 18.

At block1902, a STA (also referred to as a second wireless communication device) receives a first frame from a second device, such an AP (also referred to as a first wireless communication device). The first frame may include at least a first A-MPDU, and the first A-MPDU may include one or more MPDUs.

At block1904, the STA decodes at least a portion of a first MPDU of the one or more MPDUs in the first A-MPDU and identifies an RA field in the first MPDU.

At block1906, the STA determines that the RA field of the first MPDU includes a first value. In some implementations, the first value may be a broadcast address.

At block1908, the STA determines whether a first field in the first MPDU is addressed to the STA or a different device, in response to determining the RA field includes the first value. In some implementations, in response to determining the RA field includes the first value and determining the first field is addressed to the STA, the STA processes information associated with the first field that is directed to the STA. In response to determining the RA field includes the first value and determining the first field is not addressed to the STA (and instead the first field is addressed to a different device), the STA determines whether a second field in the first MPDU is addressed to the STA or a different device. In response to determining the RA field includes the first value and determining the second field is addressed to the STA, the STA processes information associated with the second field that is directed to the STA.

In some implementations, the first frame is a Multi-STA BA frame. The first field may include a first RA subfield having a second value, and the second field may include a second RA subfield having a third value. The STA may determine that the first field is addressed to the STA in response to determining that the second value is a first MAC address associated with the STA. The STA may determine that the second field is addressed to the STA in response to determining that the third value is the first MAC address associated with the STA.

In some implementations, the first frame may include the first field in the first MPDU having a second value, and the first frame may include a second field in a second MPDU having a third value. For example, as described inFIGS. 7 and 8, the first field of the first MPDU may be a first address4field and the second field of the second MPDU may be a second address4field. As another example, as described inFIGS. 5 and 6, the first field of the first MPDU may be a first RA field and the second field of the second MPDU may be a second RA field.

In some implementations, the first frame that is received by the STA may be a unicast Multi-STA BA frame that is be directed to a single STA. In a unicast Multi-STA BA frame, the first value of the first RA field may be the same as the second value of the first field of the first MPDU. For example, both the first RA and the first field of the first MPDU may be set to a MAC address associated with the STA. In some implementations, the first RA field may be set to a broadcast address, and the first field of the first MPDU may be set to the MAC address associated with the STA.

In some implementations, the STA may receive a second frame from the AP after receiving the first frame (such as the Multi-STA BA frame). The second frame may include a second RA field that indicates a MAC address of the STA. The second frame also may include a triggered response scheduling (TRS) control field that allocates resources and provides response information to the STA. The second frame may be a response frame (such as a Probe Response Frame, a (re)association response, an authentication response, etc.). In some implementations, instead of including a broadcast address in the RA field of the response frame, since the response frame may be directed to a single STA, the RA field of the response frame may indicate a MAC address of the STA. For example, the TRS control field may allocate an RU for the STA to use for communications (such as sending an acknowledgement frame to the AP). The TRS control field also may specify a PPDU length, a transmission power, a target RSSI, and modulation coding scheme (MCS) that the STA can use for communications with the AP.

In some implementations, the first frame received by the STA may be a frame that is directed to all unassociated STAs in the network, including at least the STA. For example, the first frame may be a beacon frame, a probe response frame, or a FILS discovery frame. The first RA field in the first MPDU may be set to a broadcast address to indicate the frame is directed to all unassociated STAs in the network.

As described above, in some aspects implementations of the subject matter described in this specification can be implemented as software. For example, various functions of components disclosed herein or various blocks or steps of a method, operation, process or algorithm disclosed herein can be implemented as one or more modules of one or more computer programs. Such computer programs can include non-transitory processor- or computer-executable instructions encoded on one or more tangible processor- or computer-readable storage media for execution by, or to control the operation of, data processing apparatus including the components of the devices described herein. By way of example, and not limitation, such storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other medium that may be used to store program code in the form of instructions or data structures. Combinations of the above should also be included within the scope of storage media.

It should be understood that any reference to an element herein using a designation such as “first,” “second,” and so forth does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient method of distinguishing between two or more elements or instances of an element. Thus, a reference to first and second elements does not mean that only two elements may be employed there or that the first element must precede the second element in some manner. Also, unless stated otherwise a set of elements may comprise one or more elements. In addition, terminology of the form “at least one of A, B, or C” or “one or more of A, B, or C” or “at least one of the group consisting of A, B, and C” used in the description or the claims means “A or B or C or any combination of these elements.” For example, this terminology may include A, or B, or C, or A and B, or A and C, or A and B and C, or2A, or2B, or2C, and so on. Furthermore, although certain aspects may be described or claimed in the singular, the plural is contemplated unless limitation to the singular is explicitly stated.