Communication apparatus and communication method for tunnel sensing by a proxy

Abstract

Communication devices and methods are provided for tunnel sensing by a proxy. One exemplary embodiment provides a first communication device comprising: circuitry to generate a request frame to request a second communication device to perform measurements on one or more links of the second communication device, each of the one or more links attached to one or more third communication devices; a transmitter that transmits the request frame to the second communication device; and a receiver receiving a report frame from the second communication device, the report frame carrying one or more reports corresponding to the measurements of the one or more links, respectively, in which a frame body of the request frame is carried in a payload field of a first data frame, and the frame body of the report frame is carried in the payload field of the second data frame.

Description

Technical Field

[0001] The present disclosure relates generally to communication methods and apparatus, and more particularly to methods and apparatus for tunnel sensing by a proxy. Background Art

[0002] Wireless Local Area Network (WLAN) sensing is being developed by the Institute of Electrical and Electronics Engineers (IEEE) 802.11 bf task group. In the task group, Sensing by Proxy (SBP) is proposed, which enables the client to obtain sensing measurements via a proxy device, but the details of the protocol / process for selecting the best link / STA for the SBP process have not yet been discussed in the task group.

[0003] However, there is limited discussion regarding communication devices and methods for sensing by a proxy in a connected wireless network or sensing by a proxy in a traditional wireless network.

[0004] Therefore, a communication device and method that can solve the above problems are needed. Furthermore, other desirable features and characteristics will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the drawings and background of the disclosure. Summary of the invention

[0005] Non-limiting and exemplary embodiments facilitate providing a communication apparatus and a communication method for tunnel sensing by a proxy.

[0006] According to one aspect of the present disclosure, a first communication device is provided, comprising: a circuit, which generates a request frame to request a second communication device to perform measurements on one or more links of the second communication device, each of the one or more links being attached to one or more third communication devices; a transmitter, which sends the request frame to the second communication device; and a receiver, which receives a report frame from the second communication device, the report frame carrying one or more reports corresponding to the measurements of the one or more links, respectively, wherein a frame body of the request frame is carried in a payload field of a first data frame, and a frame body of the report frame is carried in a payload field of a second data frame.

[0007] According to another aspect of the present disclosure, a second communication device is provided, comprising: a receiver, which receives a request frame from a first communication device to perform measurements on one or more links of the second communication device, the one or more links being attached to one or more third communication devices; a circuit, which performs the measurements; and a transmitter, which sends a report frame carrying one or more reports of measurements corresponding to the one or more links, wherein a frame body of the request frame is carried in a payload field of a first data frame, and a frame body of the report frame is carried in a payload field of a second data frame.

[0008] According to another aspect of the present disclosure, a communication method is provided, comprising: generating a request frame by a first communication device to request a second communication device to perform measurements on one or more links of the second communication device, each of the one or more links being attached to one or more third communication devices; sending the request frame to the second communication device; and receiving a report frame from the second communication device, the report frame carrying one or more reports corresponding to the measurements of the one or more links, respectively, wherein a frame body of the request frame is carried in a payload field of a first data frame, and a frame body of the report frame is carried in a payload field of a second data frame.

[0009] It should be noted that the general or specific embodiments may be implemented as a system, method, integrated circuit, computer program, storage medium, or any selective combination thereof. Additional benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. Benefits and / or advantages may be obtained individually by the various embodiments and features of the specification and drawings, and these embodiments and features do not need to be provided in full in order to obtain one or more such benefits and / or advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings are used to illustrate various embodiments and explain various principles and advantages according to the present embodiments. In the accompanying drawings, the same figure marks refer to the same or functionally similar elements throughout the separate views, and the accompanying drawings together with the following specific embodiments are incorporated into the specification and form a part of the specification.

[0011] FIG1 depicts a schematic diagram illustrating single user (SU) communication between an access point (AP) and a station (STA) in a MIMO (Multiple Input Multiple Output) wireless network.

[0012] 2 depicts a schematic diagram illustrating downlink multi-user (MU) communications between an AP and multiple STAs in a MIMO wireless network.

[0013] 3 depicts a schematic diagram illustrating trigger-based (TB) uplink MU communication between an AP and multiple STAs in a MIMO wireless network.

[0014] FIG4 depicts a schematic diagram showing the communication between a STA and an AP for a basic sensing by proxy (SBP) process.

[0015] FIG. 5 shows a schematic diagram illustrating communications in an exemplary extended SBP process.

[0016] FIG. 6 shows a schematic diagram illustrating communications in an alternative exemplary extended SBP process.

[0017] FIG. 7 shows a schematic diagram illustrating communications in an SBP process according to an example of the present disclosure.

[0018] FIG8 shows a schematic diagram illustrating communications in an exemplary SBP process according to various embodiments of the present disclosure.

[0019] FIG. 9A depicts a diagram of an exemplary SBP Ethertype 89-0d data frame, according to various embodiments of the present disclosure.

[0020] FIG9B depicts a diagram of an exemplary 1905.1 message, in accordance with various embodiments of the present disclosure.

[0021] FIG. 10 shows an exemplary flow chart illustrating an overview of an SBP process between two APs and three non-AP STAs according to various embodiments of the present disclosure.

[0022] 11 shows an exemplary flow chart illustrating a signaling overview of an SBP procedure between two APs and three non-AP STAs according to various embodiments of the present disclosure.

[0023] FIG. 12A illustrates an exemplary structure of an SBP request frame and an SBP response frame according to various embodiments of the present disclosure.

[0024] FIG. 12B depicts an exemplary structure of a protected SBP request frame and a protected SBP response frame according to various embodiments of the present disclosure.

[0025] FIG. 13 depicts an example illustration of an SBP parameter element in accordance with various embodiments of the present disclosure.

[0026] FIG. 14 depicts an example illustration of an SBP link information element in accordance with various embodiments of the present disclosure.

[0027] FIG. 15A depicts an example illustration of a protected SBP reporting frame, in accordance with various embodiments of the present disclosure.

[0028] 15B depicts an alternative example illustration of a protected SBP reporting frame, in accordance with various embodiments of the present disclosure.

[0029] FIG. 16 depicts exemplary structures of an SBP termination frame and a protected SBP termination frame according to various embodiments of the present disclosure.

[0030] FIG. 17 depicts an exemplary structure of a protected authorization verification request frame and a protected authorization verification response frame according to various embodiments of the present disclosure.

[0031] FIG. 18 illustrates communications in a variation of the SBP process according to various embodiments of the present disclosure.

[0032] FIG. 19 shows an exemplary flow chart illustrating an overview of an SBP process between three APs and four non-AP STAs according to various embodiments of the present disclosure.

[0033] 20 shows an exemplary flow chart illustrating a signaling overview of an SBP procedure between three APs and four non-AP STAs according to various embodiments of the present disclosure.

[0034] FIG. 21 depicts an exemplary 1905.1 message type in accordance with various embodiments of the present disclosure.

[0035] FIG. 22 illustrates communication in an SBP process according to various embodiments of the present disclosure, where the SBP responder is a non-AP STA or a non-AP MLD.

[0036] FIG23 depicts an example illustration of an extended capability element in accordance with various embodiments of the present disclosure.

[0037] FIG. 24 shows an exemplary flow chart illustrating an overview of an SBP process between two APs and three non-AP STAs according to various embodiments of the present disclosure.

[0038] 25 shows an exemplary flow chart illustrating a signaling overview of an SBP procedure between two APs and three non-AP STAs according to various embodiments of the present disclosure.

[0039] FIG. 26 depicts an example illustration of a sensing measurement instance in accordance with various embodiments of the present disclosure.

[0040] FIG. 27 illustrates communications in an SBP process according to various embodiments of the present disclosure, wherein a 1905.1 SBP message is used to encapsulate an SBP frame.

[0041] FIG. 28A depicts an alternative example illustration of a protected SBP reporting frame, in accordance with various embodiments of the present disclosure.

[0042] FIG28B depicts an example illustration of a sensing report trigger frame in accordance with various embodiments of the present disclosure.

[0043] FIG. 29 shows an exemplary flow chart illustrating an overview of an SBP process between three APs and three non-AP STAs according to various embodiments of the present disclosure.

[0044] 30A depicts an example illustration of an SBP Acknowledgement (Ack) frame and a protected SBP Ack frame, according to various embodiments of the present disclosure.

[0045] FIG30B depicts an example illustration of a protected SBP report request frame, in accordance with various embodiments of the present disclosure.

[0046] 31 illustrates an exemplary flow chart showing an overview of an SBP procedure between three APs and three non-AP STAs in which SBP Ack is utilized according to various embodiments of the present disclosure.

[0047] 32 depicts an example configuration of a non-AP device suitable for sensing and communication in accordance with various embodiments of the present disclosure.

[0048] 33 depicts another example configuration of a non-AP device suitable for sensing and communication in accordance with various embodiments of the present disclosure.

[0049] FIG. 34 depicts an example configuration of an AP device suitable for sensing and communication according to various embodiments of the present disclosure.

[0050] FIG. 35 shows a flow chart illustrating a method for tunnel sensing by a proxy according to various embodiments of the present disclosure.

[0051] 36 illustrates a schematic partial cross-sectional view of a STA that may be implemented for tunnel sensing by a proxy according to various embodiments of the present disclosure.

[0052] Those skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. DETAILED DESCRIPTION

[0053] The following detailed description is merely exemplary in nature and is not intended to limit the embodiments or the application and use of the embodiments. It is not intended to be bound by any theory presented in the foregoing background technology or this detailed description. In addition, in conjunction with the drawings and background technology of the present disclosure, other desired features and characteristics will become apparent from the subsequent detailed description and the appended claims.

[0054] Some embodiments of the present disclosure will be described by way of example only with reference to the accompanying drawings. Like reference numerals and characters in the drawings represent like elements or equivalents.

[0055] In the following paragraphs, certain exemplary embodiments are explained with reference to access points (APs) and stations (STAs) for sensing by a proxy, particularly in a multiple-input multiple-output (MIMO) wireless network.

[0056] In the context of IEEE 802.11 (Wi-Fi) technology, a station, interchangeably referred to as a STA, is a communication device capable of using the 802.11 protocol. Based on the IEEE 802.11-2016 definition, a STA can be any device that includes an IEEE 802.11-compliant medium access control (MAC) and physical layer (PHY) interface to the wireless medium (WM).

[0057] For example, a STA can be a laptop, desktop personal computer (PC), personal digital assistant (PDA), access point, or Wi-Fi phone in a wireless local area network (WLAN) environment. A STA can be fixed or mobile. In a WLAN environment, the terms "STA", "wireless client", "user", "user equipment", and "node" are often used interchangeably.

[0058] Similarly, an AP (which may be interchangeably referred to as a wireless access point (WAP) in the context of IEEE 802.11 (Wi-Fi) technology) is a communication device that allows STAs in a WLAN to connect to a wired network. An AP is typically connected to a router (via a wired network) as a standalone device, but it may also be integrated with or used in a router.

[0059] As described above, a STA in a WLAN can be used as an AP at different times, and vice versa. This is because a communication device in the context of IEEE 802.11 (Wi-Fi) technology can include both STA hardware components and AP hardware components. In this way, the communication device can switch between STA mode and AP mode based on actual WLAN conditions and / or requirements.

[0060] In a MIMO wireless network, "multiple" refers to multiple antennas used for transmission and multiple antennas used for reception simultaneously on a radio channel. In this regard, "multiple input" refers to multiple transmitter antennas that input radio signals into a channel, and "multiple output" refers to multiple receiver antennas that receive radio signals from a channel and enter a receiver. For example, in an N × M MIMO network system, N is the number of transmitter antennas, M is the number of receiver antennas, and N may or may not be equal to M. For simplicity, the respective numbers of transmitter antennas and receiver antennas are not further discussed in this disclosure.

[0061] In a MIMO wireless network, single-user (SU) communication and multi-user (MU) communication may be deployed for communication between communication devices such as APs and STAs. MIMO wireless networks have benefits such as spatial multiplexing and spatial diversity, which achieve higher data rates and robustness by using multiple spatial streams. According to various embodiments, the term "spatial stream" may be used interchangeably with the term "space-time stream" (or STS).

[0062] FIG. 1 depicts a schematic diagram illustrating SU communication 100 between an AP 102 and a STA 104 in a MIMO wireless network. As shown, the MIMO wireless network may include one or more STAs (e.g., STA 104, STA 106, etc.). If the SU communication 100 in a channel is performed over the entire channel bandwidth, it is referred to as full-bandwidth SU communication. If the SU communication 100 in a channel is performed over a portion of the channel bandwidth (e.g., one or more 20 MHz sub-channels within the channel are punctured), it is referred to as punctured SU communication. In the SU communication 100, the AP 102 uses multiple antennas (e.g., four antennas as shown in FIG. 1) to transmit multiple space-time streams, where all space-time streams are directed to a single communication device (i.e., STA 104). For simplicity, the multiple space-time streams directed to the STA 104 are shown as packet data transmission arrows 108 directed to the STA 104.

[0063] SU communication 100 may be configured for bidirectional transmission. As shown in FIG. 1 , in SU communication 100, STA 104 may use multiple antennas (e.g., two antennas as shown in FIG. 1 ) to transmit multiple space-time streams, where all space-time streams are directed to AP 102. For simplicity, multiple space-time streams directed to AP 102 are shown as packet data transmission arrows 110 directed to AP 102.

[0064] Thus, the SU communication 100 depicted in FIG. 1 implements both uplink SU transmissions and downlink SU transmissions in a MIMO wireless network.

[0065] FIG. 2 depicts a schematic diagram showing downlink MU (multi-user) communication 200 between an AP 202 and multiple STAs 204, 206, 208 in a MIMO wireless network. The MIMO wireless network may include one or more STAs (e.g., STA 204, STA 206, STA 208, etc.). The MU communication 200 may be OFDMA (orthogonal frequency division multiple access) communication or MU-MIMO communication. For OFDMA communication in a channel, the AP 202 simultaneously transmits multiple streams to the STAs 204, 206, 208 in the network at different resource units (Ru) within the channel bandwidth. For MU-MIMO communication in a channel, the AP 202 simultaneously transmits multiple streams to the STAs 204, 206, 208 at the same RU within the channel bandwidth using multiple antennas via spatial mapping or precoding techniques. If the RU used for OFDMA or MU-MIMO communication occupies the entire channel bandwidth, the OFDMA or MU-MIMO communication is referred to as full-bandwidth OFDMA or MU-MIMO communication. If the RU used for OFDMA or MU-MIMO communication occupies a portion of the channel bandwidth (e.g., one or more 20 MHz subchannels within the channel are punctured), then OFDMA or MU-MIMO communication is referred to as punctured OFDMA or MU-MIMO communication. For example, two space-time streams may be directed to STA 206, another space-time stream may be directed to STA 204, and yet another space-time stream may be directed to STA 208. For simplicity, the two space-time streams directed to STA 206 are shown as packet data transmission arrows 212, the space-time stream directed to STA 204 is shown as data transmission arrows 210, and the space-time stream directed to STA 208 is shown as data transmission arrows 214.

[0066] To enable uplink MU transmission, trigger-based communication is provided to the MIMO wireless network. In this regard, FIG3 depicts a schematic diagram illustrating trigger-based (TB) uplink MU communication 300 between an AP 302 and a plurality of STAs 304, 306, 308 in a MIMO wireless network.

[0067] Since there are multiple STAs 304 , 306 , 308 that respectively participate in the triggered uplink MU communication, the AP 302 needs to coordinate simultaneous transmissions of the multiple STAs 304 , 306 , 308 .

[0068] 3, AP 302 simultaneously sends trigger frames 310, 314, 318 to STAs 304, 306, 308, respectively, to indicate user-specific resource allocation information (e.g., the number of space-time streams, the starting STS number, and the allocated RUs) that each STA can use. In response to the trigger frames, STAs 304, 306, 308 can then simultaneously send their respective space-time streams to AP 302 according to the user-specific resource allocation information indicated in the trigger frames 310, 314, 318. For example, two space-time streams can be directed from STA 306 to AP 302, another space-time stream can be directed from STA 304 to AP 302, and yet another space-time stream can be directed from STA 308 to AP 302. For simplicity, two space-time flows directed from STA 306 to AP 302 are shown as packet data transmission arrows 316, the space-time flow directed from STA 304 to AP 302 is shown as data transmission arrow 312, and the space-time flow directed from STA 308 to AP 302 is shown as data transmission arrow 320.

[0069] Due to the packet / PPDU (physical layer protocol data unit) based transmission and distributed MAC (medium access control) scheme in 802.11 WLAN, there is no time scheduling (e.g., TDMA (time division multiple access) type periodic time slot assignment for data transmission) in 802.11 WLAN. Frequency and space resource scheduling is performed on a packet basis. In other words, resource allocation information is based on PPDU.

[0070] According to various embodiments, the WLAN supports non-trigger-based communication as shown in Figures 1 and 2 and trigger-based communication as shown in Figure 3. In non-trigger-based communication, a communication device sends a PPDU to one or more other communication devices in an unsolicited manner. In trigger-based communication, a communication device sends a PPDU to one or more other communication devices only after receiving a solicitation trigger frame.

[0071] According to the present disclosure, the term "sensing initiator" refers to a device that initiates sensing measurements with a STA (referred to herein as a "client") and requests sensing results from the STA. The term "sensing responder" is a STA that responds to the sensing initiator and participates in the sensing measurement. In the following various embodiments, unless otherwise specified, the terms "initiator" and "responder" refer to "sensing initiator" and "sensing responder", respectively. Typically (for example, in trigger-based (TB) sensing measurements), the initiator is the AP and the responder is a non-AP STA; however, this need not always be the case, and sometimes a non-AP STA may also be an initiator, and an AP may be a responder (for example, in non-TB sensing measurements or fine timing measurements (FTM) / ranging).

[0072] In contrast to "sensing initiator" and "sensing responder", the term "sensing by proxy (SBP) initiator" refers to a STA that initiates the SBP process and requests a device (e.g., an AP or a sensing initiator) to initiate a sensing session as a proxy sensing initiator and request sensing results from another STA (e.g., a client of a device) on its behalf. The term "SBP responder" refers to a device that responds to the SBP initiator and agrees to participate in the SBP process to become a proxy sensing initiator. Note that the SBP initiator can be a sensing responder or one of multiple sensing responders of an SBP responder (sensing initiator).

[0073] As previously mentioned, SBP was introduced in IEEE 802.11 bf, which enables clients to obtain sensing measurements using multiple radio links. FIG. 4 depicts a schematic diagram 400 showing the communication between a STA (client 0) and an AP for a basic SBP process. According to the basic concept, the process of sensing by proxy includes SBP process establishment, sensing measurement, SBP process report, and SBP process termination. During the SBP process establishment, a client (e.g., client 0) requests the AP to obtain sensing measurements with other clients (e.g., clients 1 and 2). The AP acts as a proxy initiator for the requesting client. In the various embodiments shown in the present disclosure, such a requesting client is referred to as an SBP requesting STA or an SBP initiator, and the AP is referred to as a proxy AP or an SBP responder. The proxy is established by exchanging SBP request / response frames 412 between the SBP initiator and the SBP responder. Then, the AP performs sensing measurements with one or more clients (e.g., clients 1 and 2), for example, by exchanging measurement establishment request / response frames to establish a session and / or measurement report frames 414a, 414b during (one or more) measurement instances. 4, the SBP initiator is one of the clients, and the AP may also perform sensing measurements with the SBP initiator by exchanging related frames 414c. During the SBP process report, the AP that obtains the measurement reports of the clients then reports them to the SBP initiator, for example, by transmitting an SBP report frame 416. After the SBP process report, the SBP process may be terminated at any time by the SBP initiator or the SBP responder by sending an SBP termination frame (not shown).

[0074] The above-described 11bf SBP process may be extended as shown in diagrams 500 and 600 of FIGS. 5 and 6 , respectively. For example, in diagram 500, it may be possible to enable an SBP initiator 502 to obtain sensing measurements from an AP (e.g., AP-2 504) that does not have a direct wireless medium (WM) connection to the AP. Furthermore, in diagram 600, it may be possible to enable an SBP initiator 602 to obtain sensing measurements from multiple APs acting as its proxies (e.g., AP-1 604 as a primary SBP responder, AP-2 606 as a secondary SBP responder, and AP-3 608) in a single SBP process. These examples are based on the assumption that all APs are SBP-capable and that the proxy of the SBP is always an AP.

[0075] In the present disclosure, an embodiment is provided for implementing SBP even when one or more intermediate APs do not support SBP. For example, referring to the diagram 700 of FIG. 7 , in a first scenario, the SBP initiator (e.g., STA-5 702) is within the range of an AP that does not have SBP capability (e.g., AP-1 704), but is outside the range of an AP that has SBP capability (e.g., AP-2 706). AP-1 704 may not even have 11bf capability (e.g., it may be a legacy AP). In a second scenario, none of the APs (e.g., AP-1 704, AP-2 706) may have SBP capability, but their associated non-AP STAs (e.g., STA-6 708, STA-7 710) have 11bf capability. In addition, the APs may not even have 11bf capability (e.g., they may be legacy APs). The APs and non-AP STAs may be independent APs / STAs, or may be attached to an MLD. BSS-1 (AP-1 and associated non-AP STAs STA-5 and STA-8) and BSS-2 (AP-2 and associated non-AP STAs STA-6 and STA-7) may be in different locations (e.g., in different rooms / floors, etc.). To implement SBP for these scenarios, the SBP frame may be encapsulated in a data frame (by the SBP initiator and the SBP responder) and is thus transparent to the intermediate APs. In the first case, the SBP responder is an AP (or an AP MLD). In the second case, the SBP responder is a non-AP STA (or a non-AP MLD). Advantageously, SBP may be implemented even when none of the APs within the range of the SBP initiator supports SBP. Furthermore, SBP may be implemented even when none of the APs supports SBP. For example, the data frame may be any IEEE 802.11 data frame (including valid subtypes, such as non-QoS data frames, QoS data frames, etc.) or an IEEE 802.15.4 data frame, etc. A data frame may carry a single MSDU (Medium Access Control (MAC) Service Data Unit) or may carry an aggregated MSDU (A-MSDU). A data frame may also be referred to as a data MPDU (Medium Access Control (MAC) Protocol Data Unit) and may be a standalone unit or may be carried in an aggregated MPDU (A-MPDU).

[0076] Referring to diagram 800 of FIG. 8 , in an embodiment where the SBP responder is an AP (or AP MLD), the SBP frame may be encapsulated in a data frame (e.g., in an SBP Ethernet Type 89-0d data frame or in a higher layer protocol message such as a 1905.1 (IEEE 1905.1) message), and the SBP responder may be any AP (e.g., AP-2 806) addressed by the Address 3 (A3) field of the data frame encapsulating the SBP request frame. The encapsulated SBP frame may be forwarded by an intermediate AP (e.g., AP-1 804) following the baseline addressing rules for forwarding of data frames. In order to forward the frame to the SBP responder AP, since the SBP frame is encapsulated in a data frame, the intermediate AP (e.g., AP-1 804) does not need to have SBP capability, or even 11bf capability. In diagram 800 , AP-1 804 does not have SBP capability, but AP-2 806 does. The SBP initiator (STA-5) 802 requests AP-2 806 to act as an SBP responder and perform sensing measurements on its behalf. BSS-1 (AP-1 804 and associated non-AP STAs STA-5 802 and STA-8 812) and BSS-2 (AP-2 806 and associated non-AP STAs STA-6 808 and STA-7 810) may be in different locations (e.g., in different rooms / floors, etc.). Advantageously, SBP can be implemented even when none of the APs within the range of the SBP initiator supports SBP.

[0077] FIG. 9A depicts an illustration of an exemplary SBP Ethernet type 89-0d data frame 900 according to various embodiments of the present disclosure. When encapsulated in an SBP Ethernet type 89-0d data frame (such as the SBP Ethernet type 89-0d data frame 900), the frame body of the SBP frame and the authorization verification frame (e.g., the content of the frame except the MAC header and the FCS field) may be carried in the payload field 910 within the frame body 914 of the Ethernet type 89-0d data frame 900. The authorization verification frame refers to a frame for requesting / carrying a password. The authorization verification frame exchange may be performed between the sensing responder and the SBP initiator during the measurement establishment request process. If the authorization verification is successful, the sensing responder accepts the measurement establishment request and the SBP establishment is successful. If the authorization verification is unsuccessful, the sensing responder rejects the measurement establishment request and the SBP establishment fails. Referring back to FIG8 , the SBP initiator (STA-5 802) encapsulates the SBP request frame in an SBP Ethernet type 89-0d data frame; sets the A3 field of the data frame to the MAC address of the intended SBP responder (AP-2 806), and sends the frame to AP-1 804, which forwards the frame to AP-2 806 based on the A3 field. Similarly, the SBP responder (AP-2 806) encapsulates the SBP response frame and the SBP report frame in an SBP Ethernet type 89-0d data frame; sets the A3 field of the data frame to the MAC address of the intended SBP initiator (STA-5 802), and sends the frame to AP-1 804, which forwards the frame to STA-5 802 based on the A3 field.

[0078] The Address 4 (A4) field 906 is present only when the frame is sent by one AP to another AP and carries the Source Address (SA), i.e., the MAC address of the STA from which the frame originates (i.e., the SBP initiator or SBP responder). In encapsulated SBP request frames and encapsulated SBP termination frames sent by the SBP initiator, the Address 3 (A3) field 904 carries the Destination Address (DA) and indicates the AP requested to be the SBP responder. If it is different from the AP that received the encapsulated SBP request frame (identified by the Address 1 (A1) field 902 carrying the Receiver Address (RA), the frame is forwarded to the AP addressed by the A3 field 904. When both the A1 and A3 fields match the AP's MAC address, it knows that the SBP request is addressed to it and that it is the SBP responder. When the AP receives the frame from another AP, the A4 field 906 carries the SA (e.g., the address of the SBP initiator). Similarly, in the reverse direction (e.g., in an encapsulated SBP response frame or an encapsulated SBP report frame sent by an SBP responder), when the AP is the receiver, the A3 field (DA) 904 carries the address of the SBP initiator, and the A4 field (SA) 906 carries the address of the SBP responder. In a frame sent by the final AP to the SBP initiator, the A3 field (SA) 904 carries the address of the SBP responder.

[0079] In addition, the payload type field 908 indicates a value corresponding to a payload type based on the example table 912. For example, a value of '5' corresponds to an enhanced client discovery payload type, and a value of '6' corresponds to an SBP payload type.

[0080] Alternatively, instead of an SBP Ethernet type 89-0d data frame, a new 1905.1 message type (SBP) may be used to transmit SBP-related messages, such as the 1905.1 message 950 of FIG. 9B , which depicts an example illustration of an 802.11 data frame used to encapsulate a 1905.1 SBP message. When sent over the air (e.g., between a non-AP STA and an associated AP), the 1905.1 SBP message is encapsulated using an 802.11 data frame, as shown in illustration 950. For example, the Address 2 (A2) field 956 is set to SBP (e.g., value=0x8036), and the 1905.1 Protocol TLV (SBP) field 958 is set according to the values ​​indicated in Table 2-5. The details of the 1905.1 message are described in a later section. When encapsulated in a 1905.1 message, the contents of the SBP frame and the authorization verification frame (e.g., the contents of the frame excluding the MAC header and the FCS field) may be carried as TLVs within the payload field of the 1905.1 message, while the 1905.1 message itself is carried within the frame body 954 of the data frame 950. Referring back to FIG8 , the SBP initiator (STA-5 802) encapsulates the SBP request frame within the data frame carrying the 1905.1 SBP message; sets the A3 field of the data frame to the MAC address of the intended SBP responder (AP-2 806), and sends the frame to AP-1 804, which forwards the frame to AP-2 806 based on the A3 field. Similarly, the SBP responder (AP-2 806) encapsulates the SBP response frame and the SBP report frame in a data frame carrying the 1905.1 SBP message; sets the A3 field of the data frame to the MAC address of the intended SBP initiator (STA-5 802), and sends the frame to AP-1 804, which forwards the frame to STA-5 802.8 based on the A3 field, such as 1905.1 message 950 of FIG. 9B , which depicts an example illustration of an 802.11 data frame used to encapsulate the 1905.1 SBP message. When transmitted over the air (e.g., when transmitted between a non-AP STA and an associated AP), the 1905.1 SBP message is encapsulated using an 802.11 data frame, as shown in diagram 950. For example, the Address 2 (A2) field 956 is set to SBP (e.g., value = 0x8036), and the 1905.1 Protocol TLV (SBP) field 958 is set according to the value indicated in Table 2-5. The details of the 1905.1 message are described in a later section. When encapsulated in a 1905.1 message, the contents of the SBP frame and the authorization verification frame (e.g., the contents of the frame excluding the MAC header and the FCS field) can be carried as TLVs within the payload field of the 1905.1 message, and the 1905.1 message itself is carried within the frame body 954 of the data frame 950.Referring back to FIG8 , the SBP initiator (STA-5 802) encapsulates the SBP request frame in a data frame carrying the 1905.1 SBP message; sets the A3 field of the data frame to the MAC address of the intended SBP responder (AP-2 806), and sends the frame to AP-1 804, which forwards the frame to AP-2 806 based on the A3 field. Similarly, the SBP responder (AP-2 806) encapsulates the SBP response frame and the SBP report frame in a data frame carrying the 1905.1 SBP message; sets the A3 field of the data frame to the MAC address of the intended SBP initiator (STA-5 802), and sends the frame to AP-1 804, which forwards the frame to STA-5 802 based on the A3 field.

[0081] Upon receiving SBP frames encapsulated in SBP Ethernet type 89-0d data frames or 1905.1 messages, the SBP initiator and SBP responder shall process them exactly as if they had received raw SBP frames (which are management frames).

[0082] FIG. 10 shows an exemplary flow chart 1000 illustrating an overview of the SBP process between an AP and a non-AP STA (e.g., an AP and a non-AP STA as shown in diagram 800 of FIG. 8 ). In the discovery phase, STA-5 802 (e.g., an SBP initiator) discovers AP-2 806 (e.g., an SBP responder) through basic SBP discovery, and optionally discovers non-AP STAs associated with AP-2 through enhanced client discovery. In basic SBP discovery, the SBP initiator discovers the SBP capabilities of the SBP responder (AP-2), for example, through a simplified neighbor report element in a beacon / probe response frame. In enhanced client discovery, the AP (e.g., AP-2 806) typically already has basic information about the associated STAs (e.g., STA-6 808 and STA-7 810), such as (one or more) operating channels, sensing capabilities, R2R sensing capabilities, etc., and the SBP initiator can obtain such information from the AP using a level 1 client discovery query. Upon receiving a request from the SBP initiator (or even itself), the AP may also collect other relevant information from its associated STAs, such as the location / positioning of the STA, received signal strength indicator (RSSI) or propagation loss to / from the STA (e.g., as a representative indication of the distance between the STA and the AP), information about the STA's neighboring STAs (including link metrics), and other similar information. The SBP initiator may obtain such information about the AP's associated STAs (and their neighbor STAs) from the AP using a level 2 client discovery query. Based on the above information, the SBP initiator may select one or more APs as SBP responders and one or more non-AP STAs as sensing responders for the SBP process. Alternatively, for example, if the AP does not support enhanced client discovery, or in addition to the information collected via enhanced client discovery, the SBP initiator may also use information received via other means (e.g., IP / MAC addresses provided by upper layer applications, etc.) to select SBP responders and sensing responders for the SBP process. Alternatively, it is also possible that the SBP initiator initially requests measurements from "all / many" available links, but then selects a subset of links that are most suitable for the sensing application in subsequent SBP requests. Link selection may be based on a statistical analysis of the sensing measurement reports of the links; for example, links where channel state information (CSI) feedback is not sensitive to the needs of the sensing application may be omitted in later SBP requests.

[0083] In the SBP establishment phase, the SBP initiator STA-5 802 sets the A3 (DA) field of the encapsulated SBP request frame (e.g., in an Ethernet type 89-0d data frame) to the MAC address of AP-2 806, and transmits the encapsulated SBP request to AP-2 806 (via AP-1 804) to request it to perform measurements on one or more of its links (e.g., links attached to STA-6 808 and STA-7 810). AP-2 806 performs a sensing measurement establishment with STA-6 808 and STA-7 810, and then transmits an encapsulated SBP response to STA-5 802 via AP-1 804. The encapsulated SBP response sent by AP-2 806 indicates STA-5 802 in the A3 field. In the sensing measurement phase, AP-2 806 performs sensing measurements with STA-6 808 and transmits an encapsulated SBP report to STA-5 802 via AP-1 804, and performs sensing measurements with STA-7 810 and transmits an encapsulated SBP report to STA-5 802 via AP-1 804. When sending to AP-1 804, the SBP responder (e.g., AP-2 806) sets the A3 (DA) field of the encapsulated SBP response frame and the encapsulated SBP report frame to the MAC address of STA-5 802. In the termination phase, the SBP initiator STA-5 802 sets the A3 (DA) field of the encapsulated SBP termination request to the MAC address of AP-2 806 and transmits to AP-2 806 via AP-1 804. AP-2 806 then transmits a sensing measurement termination instruction to STA-6 808 and STA-7 810.

[0084] In flowchart 1000, AP-1 804 may perform forwarding of SBP frames between STA-5 and AP-2. The A3 field value (indicating STA-5) in the encapsulated SBP response frame and the encapsulated SBP report frame shown in flowchart 1000 may only apply when the recipient is AP-1 804. When sent by AP-1 804 to its associated STAs (e.g., to STA-5 802), the A3 field carries the address of the SBP responder (e.g., AP-2 806).

[0085] FIG11 shows an exemplary flow chart 1100 illustrating a signaling overview of the flow chart 1000 shown in FIG10. In the discovery phase, STA-5 802 discovers AP-2 806 (e.g., through a beacon / probe response frame) and selects it as the SBP responder. In the SBP establishment phase, STA-5 802 sets the A3 (DA) field of the encapsulated SBP request to AP-2 806, sends the request to AP-1 804, and then AP-1 804 forwards it to AP-2 806. A sensing measurement setup is then performed between AP-2 806 and STA-6 808 (e.g., a protected sensing measurement setup (MS) request with MSID=1 is transmitted from AP-2 806 to STA-6 808, and STA-6 808 responds by transmitting a protected sensing MS response with MSID=1), and a sensing measurement setup is performed between AP-2 806 and STA-7 810 (e.g., a protected sensing MS request with MSID=2 is transmitted from AP-2 806 to STA-7 810, and STA-7 810 responds by transmitting a protected sensing MS response with MSID=2), where MSID=1 is used for STA-6 808 and MSID=2 is used for STA-7 810. AP-2 806 then selects one of the MSIDs (e.g., 1) to represent the SBP procedure. For example, AP- 2 806 sets the A3 (DA) field of the encapsulated SBP frame to STA- 5 802 , selects MSID=1 to indicate the SBP procedure, and transmits the encapsulated SBP response frame to AP- 1 804 , which forwards it to STA- 5 802 .

[0086] In the sensing measurement phase, AP-2 806 performs link measurement and reporting by initiating an appropriate measurement instance (e.g., a TB measurement instance indicating an appropriate MSID) and sending a sensing NDPA frame and a measurement PPDU (e.g., I2R NDP) to STA-6 808 and STA-7 810, and receiving a measurement report (indicating an appropriate MSID) in response to the measurement PPDU from STA-6 808 and STA-7 810, respectively. Alternatively, AP-2 806 may also solicit a measurement PPDU (e.g., R2I NDP) from STA-6 808 and STA-7 810 by sending a sensing probe trigger frame, and AP-2 calculates sensing measurements based on the R2I NDP. In the reporting phase, AP-to-AP reporting and SBP reporting are performed. For example, an encapsulated SBP report based on the measurement report or measurement PPDU from STA-6 808 may be transmitted from AP-2 806 (e.g., indicating MSID=1) to AP-1 804, which then forwards it to STA-5 802. An encapsulated SBP report based on the measurement report or measurement PPDU from STA-6 810 may also be transmitted from AP-2 806 (e.g., indicating MSID=2) to AP-1 804, which then forwards it to STA-5 802. Before transmitting the encapsulated SBP report, the SBP responder AP-2 806 may perform a translation of the MSID (if necessary) and add link information to the measurement report.

[0087] FIG. 12A shows an exemplary structure of an SBP request frame 1200 and an SBP response frame 1202 according to various embodiments of the present disclosure. FIG. 12B shows an exemplary structure of a protected SBP request frame 1204 and a protected SBP response frame 1206 according to various embodiments of the present disclosure. During SBP establishment, if there is no security association (SA) between the SBP initiator and the SBP responder, the SBP initiator and the SBP responder may exchange SBP request / response frames to establish the SBP process. If the SA exists, a protected SBP request / response frame is used. The measurement establishment ID field 1208 (e.g., in the SBP response frames 1202 and 1206) is set to the measurement establishment ID value selected by the AP that accepts the corresponding SBP request to represent the SBP process. The measurement establishment ID field 1208 is present in the SBP response frame only when the status code is equal to success. The SBP request frame, the SBP response frame, the protected SBP request frame, or the protected SBP response frame may be encapsulated in an SBP Ethernet type 89-0d data frame by including the frame body 1210, 1212, 1214, or 1216 in the payload field of the SBP Ethernet type 89-0d frame body. Similarly, the SBP request frame, the SBP response frame, the protected SBP request frame, or the protected SBP response frame may be encapsulated in a 1905.1 message by including the frame body 1210, 1212, 1214, or 1216 in the corresponding SBP TLV.

[0088] Although not shown in Figures 12A and 12B, a timeout or no response period may also be included in the SBP request frame 1200 and / or the protected SBP request frame 1204 to indicate a duration. If the SBP initiator does not receive an SBP response during the duration, the SBP process initiation will be terminated, and all resources (e.g., memory) allocated for the SBP process will be released. Similarly, a timeout or no response period may also be included in the SBP response frame 1202 and / or the protected SBP response frame 1206 to indicate a duration. If the SBP responder does not obtain any response from the SBP initiator during the duration, the SBP process will be terminated, and all resources (e.g., memory, SBP measurement establishment ID, etc.) allocated for the SBP process will be released.

[0089] The SBP initiator and the SBP responder may indicate the operational attributes to be used for the WLAN sensing process in the SBP parameter element 1300 present in the SBP request frames 1200 and 1204 and the SBP response frames 1202 and 1206. The SBP parameter element 1300 is shown in more detail in FIG. 13. In the SBP parameter element 1300, there may be an SBP parameter field 1302, which includes a link parameter field 1304, a measurement parameter field 1306, and a report parameter field 1308. The link parameter field 1304 indicates the attributes related to the link to be measured, and includes an Include SBP Initiator Bit subfield 1310, an Include R2R Bit subfield 1312, a Minimum RSSI / RCPI subfield 1314, and a Number of Measured Links subfield 1316. The Include SBP Initiator Bit subfield 1310 is set to 1 to request that the SBP initiator be included as one of the sensing responders. The Include R2R Bit subfield 1312 is set to 1 to indicate that sensing responder to sensing responder (R2R) links may also be considered. The Minimum RSSI / RCPI subfield 1314 indicates the average received signal strength indicator (RSSI) or received channel power indicator (RCPI) observed for frames sent on the selected link that is expected to be above the indicated level. The Number of Measured Links subfield 1308 indicates the number of links to be used for sensing measurements.

[0090] The measurement parameter field 1306 indicates properties related to the measurement PPDU and includes an NDP type subfield 1318 indicating a null data packet (NDP) type (or format, such as high efficiency (HE) or very high throughput (EHT) or ranging, etc.) to be used for measuring the channel, an NDP bandwidth subfield 1320 indicating a channel bandwidth of the NDP to be used for measuring the channel, and a sampling rate subfield 1322 for indicating a measurement frequency, such as the frequency at which sensing measurements are performed, such as in Hz (measurements per second). In addition, the reporting parameter field 1308 indicates properties related to SBP reporting and includes at least a measurement report type subfield 1324 and a CSI change threshold subfield 1326, the measurement report type subfield 1324 identifying the type of sensing measurement report to be used during SBP reporting, and a CSI change threshold subfield 1326 showing a number between 0 and 1 indicating a threshold to be used to determine whether a change in the measured CSI is significant enough for the AP to generate an SBP report.

[0091] The SBP responder may indicate information of the measured link corresponding to the SBP process in the SBP link information element 1400 present in the SBP response frames 1202 and 1206, and is shown in more detail in FIG. 14. In the SBP link information element 1400, there may be an SBP link information field 1402, which includes a link information count field 1404 and 1 to N link information fields 1406, the link information count field 1404 indicating the number of link information fields present in the SBP link information field 1402 (e.g., in this case, the indicated number is N). Each of the 1 to N link information fields 1406 may carry an ID (e.g., a MAC address or AID) of a STA or AP to identify the link corresponding to the sensing measurement report. The STA 1 ID always exists, while the STA 2 ID exists only for R2R links or for links of other BSSs. Alternatively, instead of the STA ID, the SBP responder may assign a unique link ID to identify each measured link. For example, the first link information field (e.g., Link Information 1 field) may include a STA 1ID subfield that identifies a non-AP STA of the AP's own basic service set (BSS) for an initiator-to-responder (I2R) or responder-to-initiator (R2I) link. The last link information field (e.g., Link Information N field) may include STA 1ID and STA 2ID subfields that identify two non-AP STAs of the AP's own BSS for the R2R link. If the link is from another AP's BSS, STA1 ID and STA2 ID may identify the STA corresponding to the link from the other BSS.

[0092] During the SBP reporting phase, the sensing measurement results obtained in the WLAN sensing process generated by the SBP request are reported to the SBP initiator (reported by the SBP responder) in a protected SBP report frame (e.g., protected SBP report frame 1500 of FIG. 15A ), which is constructed by the AP itself (if the AP is also a sensing receiver) or by adding a link information field (e.g., link information field 1504) to each sensing measurement report field (e.g., sensing measurement report field 1502) obtained in the sensing measurement report frame transmitted by the sensing responder in its own BSS and the sensing measurement report frame received from other APs. If the measurement establishment (MS) ID assigned by the other APs is different from the MSID assigned by the SBP responder for the SBP process, the SBP responder also replaces the MSID of the applicable sensing measurement report with the MSID representing the SBP process.

[0093] The link information field 1504 carries the ID (e.g., MAC address or AID) of the sensing responder to identify the link corresponding to the sensing measurement report. The STA 1 ID is always present, while the STA 2 ID is only present for R2R links or for links of other BSSs. Alternatively, the link information field 1504 may carry a unique link ID that identifies each corresponding measurement link. The sensing measurement report field 1502 may also include at least a report length field indicating the length of the sensing measurement report field 1502, a measurement establishment ID field that identifies the measurement establishment ID value selected by the AP that accepts the corresponding SBP request to represent the SBP process, a sensing measurement time field indicating a measurement timestamp (e.g., the time when the sensing receiver performs the measurement), and a sensing measurement feedback field indicating a sensing measurement result (e.g., CSI, partial_CSI, or other similar measurement result).

[0094] Alternatively, the sensing measurement report may also be carried in one or more sensing measurement report elements (each with its own element ID, length, and element ID extension field) instead of using the field, and the sensing measurement report already carries the link information field (e.g., as shown in 1552 of the protected SBP report frame 1550 of FIG. 15B). Since the extension element can carry up to 254 octets, a single element may not be sufficient to carry the entire sensing measurement report and may be segmented into two or more reports and carried in two or more elements. The report ID subfield 1554 uniquely identifies a sensing measurement report that may be segmented into multiple sensing measurement report elements and is the same across multiple segments of the same sensing measurement report. The sequence number subfield 1556 carries the sequence number of the sensing measurement report segment carried in the sensing measurement report element. The last segment subfield 1558 is set to 1 in the last sensing measurement report element transmitted with the same report ID. Otherwise, it is set to 0. The last SBP report subfield 1560 is set to 1 in the last sensing measurement report element transmitted in the SBP reporting phase of the current sensing measurement instance. Otherwise, it is set to 0.

[0095] The SBP report frame is encapsulated in an SBP Ethernet type 89-0d data frame by including a frame body 1516, 1566 in the payload field of the SBP Ethernet type 89-0d frame body, the frame body 1516, 1566 including a category field (e.g., set to "protected sensing"), an action field (e.g., set to "protected SBP reporting"), a dialog token field, and a sensing measurement report list field (e.g., including a sensing measurement report field). Similarly, the SBP report frame is encapsulated in a 1905.1 message by including the frame body 1516, 1566 in the corresponding SBP TLV. It is also possible that, instead of defining a new frame type (protected SBP report frame), the protected sensing measurement report frame is reused for SBP reporting, i.e., the protected sensing measurement report frame is also used to report sensing measurement reports to the SBP initiator.

[0096] The SBP process can be terminated by the SBP initiator or the SBP responder at any time by sending an SBP termination frame or a protected SBP termination frame (e.g., the SBP termination frame 1600 and the protected SBP termination frame 1602 of FIG. 16). The SBP termination frame 1600 includes a MAC header (e.g., including a frame control field, a duration field, an RA field, and a TA field), a category field set to "public", a public action field set to "SBP termination", a measurement establishment ID field, and an FCS field. The protected SBP termination frame 1602 includes a MAC header (e.g., including a frame control field, a duration field, an RA field, and a TA field), a category field set to "protected dual public action", a public action field set to "protected SBP termination", a measurement establishment ID field, and an FCS field. The measurement establishment ID field is set to a measurement establishment ID value assigned by the SBP responder (AP) corresponding to the SBP process to be terminated. For both termination frames, the frame body 1604 or 1606 including the Class field, Common Action field, and Measurement Setup ID field may be carried in the payload field of an encapsulated SBP Ethernet Type 89-0d frame or in a corresponding SBP TLV within a 1905.1 message.

[0097] During SBP establishment, authorization verification may be performed, wherein the AP forwards authorization verification request / response frames using the "requesting STA ID" and "target STA ID" fields, such as the protected authorization verification request frame 1700 and the protected authorization verification response frame 1702 of FIG. 17 . The protected authorization verification request frame 1700 includes a MAC header, an FCS field, and a frame body, and the frame body includes a category field set to "protected discovery", an action field set to "protected authorization verification request frame", a dialog token field, a requesting STA ID field 1704, a target STA ID field 1706, and an authentication mode field 1708. The protected authorization verification response frame 1702 includes a MAC header, an FCS field, and a frame body, and the frame body includes a category field set to "protected discovery", an action field set to "protected authorization verification response frame", a dialog token field, a requesting STA ID field 1704, a target STA ID field 1706, an authentication mode field 1708, and an authentication information field 1710.

[0098] For both frames, the requesting STA ID field 1704 indicates the ID (e.g., MAC address) of the STA requesting authorization verification, the target STA ID field 1706 indicates the ID (e.g., MAC address) of the SBP initiator STA, and the verification mode field 1708 indicates a value corresponding to the verification mode, as shown in the example table 1712. For example, a value of "0" indicates a plain text password, while a value of "1" indicates a hashed password. In addition, the verification information field 1710 may include a PN / TSF field, a length field, and a verification text field, which carries a plain text password or a hashed password based on the verification mode field 1708. In addition, the frame body 1714 of the protected authorization verification request frame 1700 and / or the frame body 1716 of the protected authorization verification response frame 1702 may be carried in the payload field of the encapsulated SBP Ethernet type 89-0d frame or in the corresponding SBP TLV within the 1905.1 message.

[0099] Upon receiving a sensing measurement setup request for an SBP procedure, the STA receiving the request may perform an over-the-air authorization verification to verify that the SBP initiator is authorized for the SBP procedure by sending a protected authorization verification request frame to the SBP initiator (via the AP). Upon receiving the protected authorization verification request frame, the SBP initiator sends a protected authorization verification response frame carrying verification information (e.g., a shared password) in the requested format.

[0100] If the STA has other means of verifying the authorization of the SBP initiator, the authorization verification request / response may be skipped. For example, the STA may maintain a list of authorized devices, or it may consult a list of authorized devices from a database on a server, or other similar methods. A hash password such as SHA-256 (key, PN / TSF "plaintext password") may be used, where the key is a public private secret key known to both parties, such as a pairwise temporary key (PTK) generated during a security association, or a dedicated secret key for sensing provided by an AP / upper layer application. PN / TSF is the value of the PN / TSF field, and the sender of the hash password can ensure that the same value is never used twice to prevent replay attacks. For example, it may be a monotonically increasing number, or it may contain the current value of the sender time synchronization function (TSF).

[0101] In an embodiment, the SBP responder (AP) may request other APs to also act as sensing initiators and perform WLAN sensing for the SBP process. The (one or more) other APs may be co-located (one or more) APs, or (one or more) other APs attached to the same MLD, or (one or more) other APs connected via wired / wireless backhaul (e.g., (one or more) APs that are part of the same enterprise network, EasyMesh network, or other similar network). The SBP responder collects sensing measurement reports from other APs and transmits them to the SBP initiator after encapsulating them into data frames. 1905.1 (IEEE 1905.1) messages are used to encapsulate SBP frames between the SBP responder and other APs. Referring to the diagram 1800 of FIG. 18 , AP-1 1804 does not have SBP capabilities, while AP-2 1806 and AP-3 1808 have SBP capabilities. AP-1 1804 does not even need to have 11bf capabilities. The SBP initiator (STA-5 1802) requests AP-2 1806 to act as an SBP responder and perform sensing measurements on its behalf. AP-2 1806 (e.g., SBP responder) requests AP-3 1808 to act as an additional sensing initiator for the SBP process. BSS-1 (e.g., a network including AP-1 1804 and associated non-AP STAs STA-5 1802 and STA-8), BSS-2 (e.g., a network including AP-2 1806 and associated non-AP STAs STA-6 and STA-7), and BSS-3 (e.g., a network including AP-3 1808 and associated STAs STA-3 and STA-4) may be in different locations (e.g., in different rooms / floors, etc.), such as a mesh network.

[0102] FIG. 19 shows an exemplary flow chart 1900 illustrating an overview of the SBP process of diagram 1800. As described above, AP-3 1808 acts as an additional sensing initiator. After performing basic SBP discovery and enhanced client discovery, SBP initiator STA-5 1802 sets the A3 (DA) field of the encapsulated SBP request to the MAC address of AP-2 1806 (in A3), specifies AP-2 1806 and AP-3 1808 as target APs, and sends the encapsulated SBP request to AP-1 1804, which forwards it to AP-2 1806. AP-2 1806 receives the encapsulated SBP request and instructs AP-3 1808 to perform WLAN sensing accordingly (e.g., via the backhaul). Higher layer protocols may be used for communication between APs (e.g., using 1905 (IEEE 1905) messages), such as for this instruction to AP-3 1808 to perform WLAN sensing.

[0103] A sensing measurement setup is then performed between the sensing responder STA-7 and the SBP responder / sensing initiator AP-2 1806 (e.g., with MSID=1), and a sensing measurement setup is performed between the additional sensing initiator AP-3 1808, the sensing responder STA-3, and the sensing responder STA-4. Thereafter, AP-3 1808 delivers the result of the sensing measurement setup to AP-2 1806 via the backhaul, and AP-2 1806 then sends an encapsulated SBP response frame to STA-5 1802 via AP-1 1804 (e.g., an encapsulated SBP response frame with the A3 field set to STA-5 1802, MSID=1, link information, and AP information). Sensing measurement instances (e.g., I2R, R2I, and R2R) may then be performed, and AP-3 1808 forwards a sensing measurement report based on the R2R sensing measurement instance (e.g., performed by STA-3 and STA-4) to AP-2 1806 via the backhaul. AP-2 1806 then sends an encapsulated SBP report frame (e.g., an encapsulated SBP report frame with the A3 field set to STA-5 1802, MSID=1, and link information of the sensing report) reporting these sensing measurement instances (e.g., I2R, R2I, and R2R) to STA-5 1802 via AP-1 1804. When sending an encapsulated SBP response frame or an encapsulated SBP report frame to AP-1 1804, the SBP responder (AP-2 1806) sets the A3 (DA) field of the encapsulated SBP response frame and the encapsulated SBP report frame to STA-5 1802.

[0104] To terminate the SBP process, an encapsulated SBP termination frame (e.g., an encapsulated SBP termination frame with the A3 field set to AP-2 1806 and MSID=1) may be sent from STA-5 1802 to AP-1 1804, which forwards it to AP-2 1806. AP-2 1806 accordingly transmits a sensing measurement termination instruction (e.g., an instruction with MSID=1) to STA-7, and AP-3 1808 accordingly transmits a sensing measurement termination instruction (e.g., an instruction with MSID=2) to STA-3 and STA-4. It should be understood that the A3 field value (e.g., indicating STA-5 1802) in the encapsulated SBP response frame and the encapsulated SBP report frame shown in flowchart 1900 is only applicable when the recipient is AP-1 1804. When sent by AP-1 1804 (towards STA-5 1802), the A3 field (SA) carries the address of the SBP responder (AP-2 1806).

[0105] 20 shows an exemplary flow chart illustrating a signaling overview of the SBP process of flow chart 1900. In the discovery phase, STA-5 1802 discovers AP-2 1806 (e.g., through a beacon / probe response frame) and selects it as the SBP responder. STA-5 1802 may send a protected client discovery query frame to AP-1 1804, and AP-1 1804 may respond by sending a protected client discovery response frame to STA-5 1802 (e.g., including a list of the AP's associated STAs and neighboring STAs).

[0106] In the SBP establishment phase, STA-5 1802 sets the A3 (DA) field of the encapsulated SBP request to AP-2 1806, specifies AP-2 1806 and AP-3 1808 as target APs (e.g., in the SBP parameter field), and sends the encapsulated SBP request to AP-1 1804, which forwards it to AP-2 1806. AP-2 1806 then instructs AP-3 1808 (e.g., an additional sensing initiator) to perform WLAN sensing. A sensing measurement establishment (e.g., I2R) is then performed between the sensing responder STA-7 and the SBP responder / sensing initiator AP-2 1806. For example, AP-2 1806 sends a protected sensing MS request to STA-7, whose MSID=1, and STA-7 then responds by sending a protected sensing MS response to AP-2 1806, whose MSID=1. A sensing measurement setup (e.g., R2R) is also performed between the additional sensing initiator AP-3 1808, the sensing responder STA-3, and the sensing responder STA-4. For example, AP-3 1808 sends a protected sensing MS request with MSID=3 to STA-3 to request the measurement setup of the link between AP-3 and STA-3 and the R2R link between STA-3 and STA-4, and then STA-3 responds by sending a protected sensing MS response with MSID=3 to AP-3 1808. Thereafter, AP-3 1808 delivers the result of the sensing measurement setup to AP-2 1806 via the backhaul. AP-2 1806 selects one of the MSIDs to represent the SBP process and sends an encapsulated SBP response frame to STA-5 1802 via AP-1 1804 (e.g., an encapsulated SBP response frame with A3 field set to STA-5 1802, status code=success, MSID=1, link information, and AP information).

[0107] Sensing measurement instances (e.g., I2R, R2I, and R2R) may then be performed, such as transmitting a measurement PPDU (e.g., indicating MSID=1 and MIID=1) to STA-7 by AP-2 1806 and receiving a measurement report (e.g., indicating MSID=1 and MIID=1) in response to the measurement PPDU from STA-7, and transmitting a measurement PPDU (e.g., indicating MSID=3 and MIID=1) to STA-4 by STA-3 and receiving a measurement report (e.g., indicating MSID=3 and MIID=1) in response to the measurement PPDU from STA-4. STA-3 transmits the measurement report (e.g., indicating MSID=3 and MIID=1) to AP-3 1808, and then AP-3 1808 forwards a sensing measurement report based on the R2R sensing measurement instance (e.g., a sensing measurement report performed by STA-3 based on the NDP sent by STA-4 and reported in the measurement report transmitted from STA-3) to AP-2 1806 via the backhaul. AP-2 1806 then sends an encapsulated SBP report frame (e.g., an encapsulated SBP report frame with the A3 field set to STA-5 1802, MSID=1, indicating STA-7 for the sensing report from STA-7, and another encapsulated SBP report frame with the A3 field set to STA-5 1802, MSID=1, indicating STA-3 and STA-4 for the sensing report from STA-3) to STA-5 1802 via AP-1 1804. When sending an encapsulated SBP response frame or an encapsulated SBP report frame to AP-1 1804, the SBP responder (AP-2 1806) sets the A3 (DA) field of the encapsulated SBP response frame and the encapsulated SBP report frame to STA-5 1802. In addition, the SBP responder AP-2 1806 may perform a translation of the MSID (if necessary) and add link information to the measurement report(s) before sending the encapsulated SBP report frame.

[0108] Between APs with SBP capability (e.g., AP-2 1806 and AP-3 1808), a new 1905.1 message type (SBP) may be used to transmit SBP-related messages, such as the 1905.1 message 2100 of FIG. 21. The 1905.1 message 2100 includes a destination address (DA) field, a source address (SA) field, an Ethernet type field, a payload field, and an FCS field. The payload field includes a message version field, a message type field (e.g., set to a value of 0x8036 to indicate an SBP message type), a message identifier (MID) field, a segment identifier (FID) field, a last segment indicator field, a last segment indicator field, a relay indicator field, a 1905.1 protocol TLV (type, length, value) field, and a message TLV end field. A new 1905.1 TLV may be defined for the 1905.1 protocol TLV field to carry the content of the corresponding SBP message, such as shown in Table 1 below.

[0109]

[0110] Table 1

[0111] A single 1905.1 message type may be defined for all SBP messages, where individual SBP frame types are distinguished by TLV types. In the forward direction (e.g., from an SBP initiator to an SBP responder), upon receiving an encapsulated SBP frame, the SBP responder (AP-2) converts the SBP frame (e.g., SBP request or SBP termination) into a corresponding 1905.1 message and forwards it to the next AP (AP-3). Similarly, in the reverse direction (e.g., from an SBP responder to an SBP initiator), upon receiving a 1905.1 message carrying an SBP message (e.g., SBP response or SBP report), the SBP responder (AP-2) converts the 1905.1 message into a corresponding encapsulated SBP frame and forwards it to the SBP initiator.

[0112] Table 2 below shows the contents of the SBP request frame in the SBP request TLV format.

[0113]

[0114] Table 2

[0115] Table 3 below shows the contents of the SBP response frame in the SBP response TLV format.

[0116]

[0117] Table 3

[0118] Table 4 below shows the contents of the SBP report frame in the SBP report TLV format.

[0119]

[0120] Table 4

[0121] Table 5 below shows the contents of the SBP Termination frame for the SBP Termination TLV format.

[0122]

[0123] Table 5

[0124] In an embodiment, the SBP responder may be a non-AP STA (or a non-AP MLD). The non-AP STA supports the SBP process as an SBP responder, i.e., it has SBP responder capability. Referring to diagram 2200 of FIG. 22 , AP-1 2204 and AP-2 2206 do not have SBP capability, but STA-6 2208 has SBP responder capability. The SBP initiator (STA-5 2202) requests STA-6 2208 to act as an SBP responder and perform sensing measurements on its behalf. STA-6 2208, acting as a sensing initiator, performs sensing on two links (STA6 - AP-2 and STA-6 - STA-7) on behalf of STA-5 2202. The SBP frame is encapsulated in an Ethernet type 89-0d data frame, and the SBP responder may be any non-AP STA (e.g., such as STA-7) addressed by the address 3 (A3) field of the data frame encapsulating the SBP request frame. The encapsulated SBP frame is forwarded by the intermediate AP(s) (e.g., AP-1 2204, AP-2 2206) following the baseline rules for forwarding data frames. The AP associated with the SBP responder (e.g., an associated AP such as AP-2 2206) may or may not be 11bf capable, and the other intermediate APs (e.g., AP-1 2204) do not even need to be 11bf capable. Advantageously, SBP can be implemented even when none of the APs support SBP.

[0125] FIG. 23 depicts an example illustration of an extended capability element 2300 used in the SBP process of FIG. 22 . The extended capability element 2300 may include an SBP responder subfield 2304 in the extended capability field indicating whether the SBP responder role is supported. For example, a value of '0' indicates that the SBP responder role is not supported, while a value of '1' indicates that the SBP responder role is supported. In addition, the SBP subfield bit 2302 in the extended capability field may indicate the ability of the non-AP STA to assume the SBP initiator role.

[0126] FIG24 shows an exemplary flow chart 2400 illustrating an overview of the SBP process of diagram 2200. As described above, non-AP STA-6 2208 acts as an SBP responder. After performing basic SBP discovery and enhanced client discovery, SBP initiator STA-5 2202 discovers that STA-6 has SBP responder capabilities. STA-5 2202 sets the A3 (DA) field of the encapsulated SBP request to STA-6 2208 (in A3) and sends the encapsulated SBP request to STA-6 2208.

[0127] STA-6 2208 then performs a sensing measurement setup with AP-2 2206 (e.g., with MSID=1) and STA-7 (e.g., with MSID=2). Upon receiving the encapsulated SBP request, a tunnel direct link setup (TDLS) and TDLS peer key security may also be performed between the non-AP STA SBP responder and another non-AP STA before any sensing measurement setup. Thereafter, STA-6 2208 sends an encapsulated SBP response frame (e.g., an encapsulated SBP response frame with MSID=1 and link information) to STA-5 2202. STA-6 2208 performs sensing measurements with AP-2 2206 and transmits a corresponding encapsulated SBP report (e.g., an encapsulated SBP report with A3=STA-5, MSID=1, and link information corresponding to the sensing measurement) to STA-5 2202. STA- 6 2208 also performs sensing measurement with STA- 7 and transmits a corresponding encapsulated SBP report (eg, an encapsulated SBP report with A3=STA- 5 , MSID=1 , and link information corresponding to the sensing measurement) to STA- 5 2202 .

[0128] To terminate the SBP process, an encapsulated SBP termination frame (e.g., an encapsulated SBP termination frame with the A3 field set to STA-6 2208 and MSID=1) may be sent from STA-5 2202 to STA-6 2208. STA-6 2208 accordingly transmits a sensing measurement termination instruction to AP-2 2206 (e.g., with MSID=1) and STA-7 (e.g., with MSID=2). Thereafter, a TDLS teardown may be performed.

[0129] If the associated AP (e.g., AP-2 2206) is 11bf capable, the non-AP STA SBP responder (STA-6 2208) can perform sensing on the link with the AP. Otherwise, it can perform sensing measurements only with other non-AP STAs with 11bf capability. In the encapsulated SBP request frame and the encapsulated SBP termination frame, the A3 field (DA) indicates the non-AP STA (STA-6 2208) requested to be the SBP responder, and if the non-AP STA is not associated with the AP (e.g., AP-1 2204) identified by the A1 field (RA), the frame is forwarded to the AP associated with the non-AP STA (e.g., AP-2 2206), and the A4 field (SA) carries the address of the SBP initiator. When the frame is sent by the AP associated with the SBP responder (e.g., AP-2 2206) to the SBP responder, the A3 field (SA) carries the address of the SBP initiator. Similarly, in the reverse direction (e.g., in an encapsulated SBP response frame or an encapsulated SBP report frame), when the AP is the receiver, the A3 field (DA) carries the address of the SBP initiator and the A4 field (SA) carries the address of the SBP responder (STA-6 2208).

[0130] 25 shows an exemplary flow chart illustrating a signaling overview of the SBP process of flow chart 2400. In the discovery phase, STA-5 2202 discovers STA-6 2208 (e.g., through beacon / probe response frames and client discovery response frames) and selects it as the SBP responder. STA-5 2202 may send a protected client discovery query frame to AP-1 2204, and AP-1 2204 may respond by sending a protected client discovery response frame to STA-5 2202 (e.g., including a list of the AP's associated STAs and neighboring STAs).

[0131] In the SBP establishment phase, STA-5 2202 sets the A3 (DA) field of the encapsulated SBP request to STA-6 2208 and sends the encapsulated SBP request to AP-1 2204, which forwards it to STA-6 2208 via AP-2 2206. Sensing measurement establishment is then performed between STA-6 2208 and AP-2 2206. For example, STA-6 2208 sends a protected sensing MS request with MSID=1 to AP-2 2206, which then responds by sending a protected sensing MS response with MSID=1 to STA-6 2208. Sensing measurement establishment is also performed between STA-6 2208 and STA-7. For example, STA-6 2208 sends a protected Sensing MS Request with MSID=2 to STA-7, which then responds by sending a protected Sensing MS Response with MSID=2 to STA-6 2208. Thereafter, STA-6 2208 selects one of the MSIDs to represent the SBP procedure and sends an encapsulated SBP response frame (e.g., an encapsulated SBP response frame with A3 field set to STA-5 2202, Status Code=Success, MSID=1) to STA-5 2202 via AP-1 2204.

[0132] Sensing measurement instances (e.g., I2R, R2I, and R2R) may then be performed, such as transmitting, by STA-6 2208, a measurement PPDU (e.g., indicating MSID=1 and MIID=1) to AP-2 2206 and receiving, from AP-2 2206, a measurement report (e.g., indicating MSID=1 and MIID=1) in response to the measurement PPDU, and transmitting, by STA-6 2208, a measurement PPDU (e.g., indicating MSID=2 and MIID=1) to STA-7 and receiving, by STA-7, a measurement report (e.g., indicating MSID=2 and MIID=1) in response to the measurement PPDU. STA-6 2208 then sends an encapsulated SBP report frame to STA-5 2202 via AP-1 2204 (e.g., an encapsulated SBP report frame with MSID=1 indicating STA-7 for a sensing report from STA-7, and another encapsulated SBP report frame with MSID=1 indicating AP-2 2206 for a sensing report from AP-2 2206).

[0133] When sending an encapsulated SBP response frame or an encapsulated SBP report frame to AP-2 2206 for forwarding to STA-5 2202 (via AP-1 2204), the SBP responder (STA-6 2208) sets the A3 (DA) field of the encapsulated SBP response frame and the encapsulated SBP report frame to STA-5 2202. In addition, the sensing initiator (also STA-6 2208) may perform a translation of the MSID (if necessary) and add link information to the measurement report(s) before sending the encapsulated SBP report frame. Although not shown in the figure, a P2P negotiation (e.g., tunnel direct link setup (TDLS)) may be performed between a non-AP STA SBP responder and another non-AP STA prior to any sensing measurement setup and subsequent sensing measurement and reporting between non-AP STAs. The P2P negotiation (e.g., TDLS link) may also be torn down when the SBP process terminates. The A3 field (DA) value in the encapsulated SBP response frame and encapsulated SBP report frame in the figure (STA-5 2202) is applicable only when the recipient is an AP (AP-1 2204 or AP-2 2206). When forwarded by AP-2 2206 to AP-1 2204, the A4 field (SA) carries the address of the SBP responder (STA-6 2208). When sent by AP-1 2204 (towards STA-5 2202), the A3 field (SA) carries the address of the SBP responder (STA-6 2208).

[0134] 26 depicts an example diagram 2600 of a sensing measurement instance (e.g., for non-TB sensing measurements) that may be utilized in flowchart 2400. For example, the SBP responder (STA-6 2208) performs non-TB sensing measurements with AP-2 2206 (see sensing measurement instance 2602) and STA-7 (see sensing measurement instance 2604). The sensing measurements with STA-7 are performed over a TDLS link. For simplicity, SBP responses, sensing measurement establishment, etc. are not shown in diagram 2600. Upon receiving an SBP request, before any sensing measurement establishment, if a P2P link with STA-7 does not already exist, the SBP responder (STA-6 2208) initiates a P2P link with STA-7, such as tunnel direct link establishment (TDLS) and TDLS peer key security. All subsequent communications between STA-6 and STA-7 occur over the TDLS link.

[0135] In an embodiment, the 1905.1 SBP message may be used to encapsulate the SBP frame from start to finish (i.e., from the SBP initiator to the SBP responder). It is assumed that the SBP initiator and the SBP responder, as well as any intermediate APs, support the 1905.1 SBP message. The AP may be part of an AP network (e.g., an EasyMesh AP network). Referring to diagram 2700 of FIG. 27 , the SBP responder may be an AP (e.g., AP-3 2708) or a non-AP STA (e.g., STA-3 2710), as indicated by the MAC address field of the SBP responder of the SBP request TLV (e.g., as shown in Table 2-5 above). AP-1 2704, AP-2 2706, and AP-3 2708 do not have SBP capabilities, but STA-3 2710 has SBP responder capabilities. The SBP initiator (STA-5 2702) requests STA-3 2710 to act as an SBP responder and perform sensing measurements on its behalf. STA-3 2710, acting as a sensing initiator, performs sensing on both links (STA-3 - AP-3 and STA-3 - STA-4) on behalf of STA-5 2702. The AP associated with the SBP responder (when it is a non-AP STA) (i.e., the associated AP, such as AP-3 2708) may or may not have 11bf capabilities. In addition, other intermediate APs (e.g., AP-1 2704, AP-2 2706) do not even need to have 11bf capabilities. This advantageously enables simpler operation because the same protocol (1905.1) is used to encapsulate SBP messages.

[0136] When sent over the air (e.g., between a non-AP STA and an associated AP), the 1905.1 SBP message is encapsulated using an 802.11 data frame, as shown in diagram 950 in FIG. 9B . For example, the Address 2 (A2) field 952 is set to SBP (e.g., value = 0x8036), and the 1905.1 Protocol TLV (SBP) field 958 is set according to the values ​​indicated in Table 2-5. When sent over a wired interface (e.g., between two APs), the 1905.1 SBP message is encapsulated in an appropriate layer 2 packet (e.g., Ethernet), and the format is as described in FIG. 21 .

[0137] FIG28A depicts an alternative example illustration of a protected SBP report frame according to various embodiments of the present disclosure. The SBP report frame 2800 may carry one or more sensing measurement reports 2802, each sensing measurement report 2802 carrying a sensing measurement feedback field 2804, which contains the entirety or a segment of the CSI measurement results of the link. The report length field 2804 indicates the length of the sensing measurement report field 2802 (in units of eight bits) and is large enough (e.g., 2 eight bits) to signal the maximum possible sensing measurement report field. The remaining fields are as described in FIG15B. Although FIG28A depicts a protected SBP report frame, the same format may also be used for a protected sensing measurement report frame to report the results of sensing measurements between a sensing receiver and a sensing initiator, except that the action field of the frame is set to a protected sensing measurement report instead of a protected SBP report. Sometimes, the sensing measurement feedback (i.e., CSI measurement feedback) may be too large (e.g., greater than 11450 octets), causing the main frame (e.g., SBP report frame or protected sensing measurement report frame) to exceed the maximum MPDU size (11454 octets). In such a case, the CSI measurement feedback (identified by the report ID) is divided into two or more segments of the same size except for the last segment, each segment is identified by a unique sequence number and carried in a different sensing measurement report field 2802. If the sensing initiator does not receive one or more segments of the sensing measurement report during the TB sensing measurement instance, the sensing initiator can send a sensing report trigger frame 2850 as shown in FIG. 28B to selectively solicit the missing segments. The report ID field 2852 indicates the ID of the sensing measurement report, and the segment number bitmap field 2854 carries a bitmap (e.g., 16 bits), each bit set to 1 (starting from the first bit B0 of the first segment) indicates the sequence number (SN) of the segment requested for retransmission, for example, bits 3 and 5 set to 1 indicate that segments with SN=3 and 5 are requested to be retransmitted.

[0138] FIG29 shows an exemplary flow chart 2900 illustrating an overview of the SBP process of FIG2700. Non-AP STA-3 2710 acts as an SBP responder (rather than an AP). After performing basic SBP discovery and enhanced client discovery, SBP initiator STA-5 2702 discovers that STA-3 2710 has SBP responder capabilities. STA-5 2702 sends an encapsulated SBP request to STA-3 2710.

[0139] STA-3 2710 then performs a sensing measurement setup with AP-3 2708 (e.g., with MSID=1) and STA-4 (e.g., with MSID=2). Upon receiving the encapsulated SBP request, a tunnel direct link setup (TDLS) and TDLS peer key security may also be performed between the non-AP STA SBP responder and another non-AP STA before any sensing measurement setup. Thereafter, STA-3 2710 sends an encapsulated SBP response frame to STA-5 2702. STA-3 2710 performs sensing measurements with AP-3 2708 and transmits a corresponding encapsulated SBP report to STA-5 2702. STA-3 2710 also performs sensing measurements with STA-4 and transmits a corresponding encapsulated SBP report to STA-5 2702.

[0140] To terminate the SBP process, an encapsulated SBP termination frame may be sent from STA-3 2710 to STA-5 2702. STA-3 2710 accordingly transmits a sensing measurement termination instruction to AP-3 2708 (eg, with MSID = 1) and STA-4 (eg, with MSID = 2). Thereafter, TDLS teardown may be performed.

[0141] If the associated AP (e.g., AP-3 2708) is 11bf capable, the non-AP STA SBP responder (STA-3 2710) can perform sensing on the link with the AP. Otherwise, it can perform sensing measurements only with other non-AP STAs (e.g., STA-4) that are 11bf capable. The main difference between the SBP process of flowchart 2800 and flowchart 1800 is that the communication between STA-5 2702 and STA-3 2710 is under end-to-end encapsulation.

[0142] 30A depicts an example illustration of an SBP Ack frame 3000 and a protected SBP Ack frame 3002 according to various embodiments. When the SBP initiator and the SBP responder are not directly connected via a wireless medium (WM), it may sometimes be difficult to determine whether the SBP message has been delivered to the peer STA because the 802.11 Ack frame is not forwarded beyond the current (immediate) BSS, resulting in unnecessary timeouts or other similar problems. The SBP Ack frame 3000 (and its protected version, the protected SBP Ack frame 3002) may be used to confirm the receipt of any SBP message. Specifically, the SBP frame type field 3004 indicates the type of SBP frame confirmed by the SBP Ack frame 3000 or 3002, for example, by indicating a value corresponding to the SBP frame type as shown in Table 6 below.

[0143]

[0144] Table 6

[0145] In addition, the Dialogue Token field 3006 value may be copied from the Dialogue Token field of the SBP frame being acknowledged. In the SBP Ack frame of some SBP frames that do not contain a Dialogue Token field (e.g., an SBP Report frame), the Dialogue Token may alternatively carry the Measurement Instance ID. The Dialogue Token field 3006 uniquely identifies the SBP frame being acknowledged. The SBP Ack frame is encapsulated in an SBP EtherType 89-0d Data frame by including a Frame Body 3008 in the Payload field of the SBP EtherType 89-0d Frame Body.

[0146] When the SBP Ack TLV is carried in the 1905.1 message, it carries the content of the SBP Ack frame, such as the SBP Ack TLV format shown in Table 7 below.

[0147]

[0148] Table 7

[0149] 30B depicts an example illustration of a protected SBP report request frame 3050 according to various embodiments. The SBP initiator may use the protected SBP report request frame to request the SBP responder to send one or more SBP reports corresponding to a measurement establishment ID and / or a report ID, or to selectively retransmit one or more segments of an SBP report. The protected SBP report request frame 3050 carries a measurement establishment ID field 3056 indicating a measurement establishment ID representing an SBP process, and an SBP report request list field 3052 including a count field 3054 and one or more SBP report fields, the count field 3054 indicating the number of SBP report fields included in the SBP report request list field. Each SBP report field includes a report ID field 3058 and a segment number bitmap field 3060. The report ID field 3058 indicates the ID of the SBP report, and the segment number bitmap field 3060 carries a bitmap (e.g., 16 bits), each bit set to 1 (starting from the first bit B0 of the first segment) indicates the sequence number (SN) of the segment requested for retransmission, for example, bits 3, 5 set to 1 indicate that segments with SN=3 and 5 are requested for retransmission. If the SBP report request frame does not include an SBP report request list, it indicates that the SBP initiator is requesting the SBP responder to send any available SBP report. The SBP report request frame is encapsulated in an SBP Ethernet type 89-0d data frame by including a frame body 3062 in the payload field of the SBP Ethernet type 89-0d frame body.

[0150] When carried in a 1905.1 message, the SBP Report Request TLV carries the content of the SBP Ack frame, such as the SBP Report Request TLV format shown in Table 8 below.

[0151]

[0152] Table 8

[0153] An example of how SBP Ack and SBP Report Request can be utilized is shown in the flowchart 3100 of FIG. 31 . The SBP initiator may specify a timeout value T1 in the SBP request frame, such that if the SBP responder cannot send an SBP response within T1, the SBP responder must send an SBP Ack frame to the SBP initiator. In addition, the SBP responder may specify a timeout value T2 in the SBP response frame, such that the SBP initiator must send an SBP Ack frame to the SBP responder within T2. ​​During link measurement and reporting, the SBP responder performs sensing measurements (e.g., for MIID=1) and transmits an SBP report to the SBP initiator. If the SBP Ack is not received within T2, the SBP responder retransmits the SBP report to the SBP initiator. Once the SBP Ack is received, the SBP report for the next MIID may be sent. The timeout values ​​(T1, T2) may be carried in the SBP request and SBP response, respectively, and may have the same or different durations, or they may be constant values ​​specified by the 802.11 specification. If no response to the SBP frame / message is received from the peer STA within the specified timeout duration, the transmitter (SBP initiator or SBP responder) may choose to retransmit the SBP frame after an implementation-dependent time period; if no response is still received, the SBP process may be torn down and all allocated resources for the SBP process may be released. The SBP initiator (STA-5) may also request the SBP initiator (STA-3) to retransmit one or more segments of the SBP report by sending an SBP report request 3102 indicating the requested report ID and the sequence number of the requested segment. This may be used, for example, when some segments of the SBP report are not received correctly. Upon receiving the SBP report request, the SBP responder retransmits the requested segment of the SBP report 3104. Although the above example shows a case where the SBP initiator and the SBP responder do not have a direct WM connection, the SBP Ack frame may also be used when both are part of the same BSS (e.g., when the SBP initiator and the SBP responder have a direct WM connection).

[0154] FIG32 shows an example configuration of a non-AP communication device 3200. According to various embodiments of the present disclosure, the communication device 3200 is implemented as a STA for tunnel sensing by a proxy. The communication device 3200 may include at least one radio transmitter 3203 and at least one radio receiver 3202 (for simplicity, only one radio transmitter, radio receiver and antenna are shown in FIG32 ) cooperating with at least one antenna 3222, respectively for signal transmission and reception. The communication device 3200 also includes a circuit 3204 that implements 802.11 MAC / PHY sublayer functions (802.11 MAC / PHY sublayer 3204), which includes a sensing module 3206 for channel measurement, layer management service interfaces such as MLME SAP 3208 and MAC SAP 3210 (through which defined primitives are exchanged to transfer information and layer management functions such as WLAN sensing can be called), and a higher layer application (e.g., WLAN sensing abstraction layer 3214) that communicates with the 802.11 MAC / PHY 3204 through the MLME SAP 3208.

[0155] In addition, the 802.11 MAC / PHY sublayer 3204 can communicate with a WLAN data application (not shown) via a MAC SAP 3210. In this example, the sensing module 3206 performs channel measurements and provides raw results to the WLAN sensing abstraction layer 3214 via a WLAN sensing API. The WLAN abstraction layer 3214 collects and merges channel measurement results from 802.11 devices, and can process the results (e.g., smooth compression, etc.), and then pass the processed results to WLAN sensing client applications, such as WLAN sensing client application 1 (vital sign detection) 3216 and WLAN sensing client application 2 (motion detection) 3218. The WLAN sensing client applications (such as 3216, 3218) can perform WLAN sensing based on the channel measurements (e.g., using application-specific machine learning algorithms, etc.) and provide results of the WLAN sensing, in this case, providing presence / absence of human detection and human motion detection.

[0156] The communication device also includes a layer-related entity Station Management Entity (SME) (not shown) that performs functions on behalf of the general system management entity and will implement standard management protocols, such as to ensure correct MAC operation. The layer-related entities provide interfaces such as MLME SAP 3208 and PLME SAP (not shown) for exchanging primitives and communicating with MLME and PLME respectively.

[0157] The MAC / PHY sublayer 3204 may receive information or WLAN sensing related MAC / PHY parameters to form an SBP request frame. Then, the trigger frame or PPDU is sent to one or more communication devices (e.g., AP or SBP responder) via at least one radio transmitter 3203 via antenna 3222.

[0158] The MAC / PHY sublayer 3204 may also unpack a response or measurement PPDU (eg, an SBP response frame and an SBP report frame received from another communication device) and pass information related to the received PPDU to the sensing module 3206 .

[0159] The sensing module 3206 includes a link / STA / AP selection module 3220 that selects one or more links, STAs, and / or APs to participate in the SBP process. The selection may be included in the frame, for example, as target STA / link or target AP information. The sensing module 3206 also includes an SBP responder module 3221 that generates responses to SBP-related communications that may be received from other STAs / APs.

[0160] FIG33 shows another example configuration of a communication device 3300. According to various embodiments of the present disclosure, the communication device 3300 is implemented as a non-AP STA for tunnel sensing by a proxy. The communication device 3300 includes a power supply 3302, a memory 3304, a central processing unit (CPU) 3306 including at least one processor, an auxiliary storage device 3308, a wired interface (I / F) 3310, and a wireless I / F 3312. The memory 3304 may be a non-transitory computer-readable storage medium in which data representing instructions that can be executed by at least one processor of the CPU 3306 to communicate with the wireless I / F 3312 to perform an enhanced client discovery process according to various embodiments described in the present disclosure is stored. The wireless I / F 3312 includes a MAC layer 3314 and a PHY layer 3316. The PHY layer 3316 is connected to a radio transmitter (not shown), a radio receiver (not shown), and an antenna 3322 for sending / receiving signals to / from other communication devices (e.g., STA / AP). Alternatively, the communication device 3300 may transmit / receive signals to / from other communication devices (eg, STA) via the wired I / F 3310. The auxiliary storage device 3308 may store the AID of the associated communication device.

[0161] The MAC layer 3314 also includes a sensing module 3318. The sensing module 3318 generates and processes frames (e.g., client discovery query / response frames, authorization verification request / response frames, report frames) according to the above-mentioned various embodiments to perform the SBP process (e.g., as an SBP initiator / responder). The sensing module 3318 includes a link / STA / AP selection module 3320, which selects one or more links, STAs and / or APs to participate in the SBP process. The selection can be included in the frame, for example, as target STA / link or target AP information. The sensing module 3318 also includes an SBP responder module 3321, which generates a response to SBP-related communications that can be received from other STAs / APs.

[0162] FIG. 34 shows another example configuration of a communication device 3400. According to the present disclosure, the communication device 3400 is implemented as an AP for tunnel sensing by a proxy. The communication device 3400 includes a power supply 3402, a memory 3404, a central processing unit (CPU) 3406 including at least one processor, an auxiliary storage device 3408, a wired I / F 3410, and a wireless I / F 3412. The memory 3404 may be a non-transitory computer-readable storage medium in which data representing instructions that can be executed by at least one processor of the CPU 3406 to communicate with the wireless I / F 3412 to perform multi-generation random access according to various embodiments in the present disclosure are stored. The wireless I / F 3412 includes a MAC layer 3414 and a PHY layer 3416. The PHY layer 3416 is connected to a radio transmitter (not shown) for sending / receiving signals to / from other (base station) communication devices, a radio receiver (not shown), and an antenna 3422. Alternatively, the communication device 3400 may transmit / receive signals to / from other communication devices via the wired I / F 3410 .

[0163] The MAC layer 3414 also includes a sensing module 3418. The sensing module 3418 generates and processes frames (e.g., client discovery query / response frames, authorization verification request / response frames, report frames) according to the various embodiments described above to perform the SBP process (e.g., as an SBP responder, a sensing initiator, or a sensing responder). The sensing module 3418 includes a link / STA / AP selection module 3420, which selects one or more links, STAs, and / or other APs to participate in the SBP process. The selection can be included in the frame, for example, as target STA / link or target AP information in a sensing request sent to another AP.

[0164] The AP-to-AP communication module 3422 facilitates communication between the wired I / F 3410 and the wireless I / F 3412. For example, multiple APs may be connected via a wired backhaul in the wired I / F 3410, and the APs communicate with other STAs via the wireless I / F 3412. When a frame (e.g., an SBP request frame) is received from a non-AP STA via the wireless I / F 3412, the AP-to-AP communication module 3422 may forward the frame (or generate another frame with information) to other co-located APs or other APs within the same MLD, or APs interconnected via a wired backhaul link in the wired I / F 3410. Similarly, when a frame (e.g., an SBP request frame) is received from another AP via the wired I / F 3410, the AP-to-AP communication module 3422 may forward the frame (or generate another frame with the information) to a STA wirelessly connected to the communication device 3400 via the wireless IF 3412.

[0165] FIG35 shows a flow chart 3500 illustrating a communication method according to various embodiments. At step 3502, a request frame is generated by a first communication device to request a second communication device to perform measurements on one or more links of the second communication device, each of the one or more links being attached to one or more third communication devices. At step 3504, the request frame is sent to the second communication device. At step 3506, a report frame is received from the second communication device, the report frame carrying one or more reports corresponding to the measurements of the one or more links, respectively, wherein a frame body of the request frame is carried in a payload field of a first data frame, and a frame body of the report frame is carried in a payload field of a second data frame.

[0166] 36 shows a schematic partial cross-sectional view of a communication device 3600 that may be implemented for tunnel sensing by a proxy according to various embodiments. According to various embodiments, the communication device 3600 may be implemented as a STA or an AP.

[0167] The various functions and operations of the communication device 3600 are arranged into layers according to a hierarchical model. In this model, the lower layers report to and receive instructions from the higher layers according to the IEEE specification. For simplicity, the details of the hierarchical model are not discussed in this disclosure.

[0168] As shown in FIG. 36 , the communication device 3600 may include a circuit 3614, at least one radio transmitter 3602, at least one radio receiver 3604, and multiple antennas 3612 (for simplicity, only one antenna is depicted in FIG. 36 for illustration purposes). The circuit may include at least one controller 3606 for software and hardware assistance to perform the tasks it is designed to perform, including controlling communication with one or more other devices in the wireless network. The at least one controller 3606 may control at least one transmit signal generator 3608 and at least one receive signal processor 3610, the at least one transmit signal generator 3608 is used to generate a frame to be transmitted to one or more other STAs or APs through the at least one radio transmitter 3602, and the at least one receive signal processor 3610 is used to process frames received from one or more other STAs or APs through the at least one radio receiver 3604. The at least one transmit signal generator 3608 and the at least one receive signal processor 3610 may be independent modules of the communication device 3600, which communicate with the at least one controller 3606 for the above functions. Alternatively, the at least one transmit signal generator 3608 and the at least one receive signal processor 3610 may be included in the at least one controller 3606. It will be appreciated by those skilled in the art that the arrangement of these functional modules is flexible and may vary according to actual needs and / or requirements. Data processing, storage and other related control devices may be provided on an appropriate circuit board and / or in a chipset.

[0169] In various embodiments, at least one radio transmitter 3602, at least one radio receiver 3604, and at least one antenna 3612 may be controlled by at least one controller 3606. Furthermore, while only one radio transmitter 3602 is shown, it should be understood that more than one such transmitter may be present.

[0170] In various embodiments, at least one radio receiver 3604 together with at least one receive signal processor 3610 forms a receiver of the communication device 3600. The receiver of the communication device 3600 provides the functionality required for tunnel sensing by the agent. Although only one radio receiver 3604 is shown, it should be understood that there may be more than one such receiver.

[0171] The communication device 3600 provides the functionality required for tunnel sensing by an agent. For example, the communication device 3600 may be a first communication device. The circuit 3614 may generate a request frame to request a second communication device to perform measurements on one or more links of the second communication device, each of which is attached to one or more third communication devices. The transmitter 3602 may send a request frame to the second communication device. The receiver 3604 may receive a report frame carrying one or more reports of measurements corresponding to the one or more links, respectively, from the second communication device, wherein the frame body of the request frame is carried in a payload field of a first data frame, and the frame body of the report frame is carried in a payload field of a second data frame.

[0172] The request frame may be an SBP establishment request frame, and the first data frame or the second data frame may be an IEEE 802.11 data frame or an IEEE 802.15.4 data frame. The measurement may be a sensing measurement, and the report frame may be an SBP report frame. The receiver 3604 may also receive an SBP establishment response frame indicating whether the SBP establishment request is accepted, and the frame body of the SBP establishment response frame is carried in the payload field of the third data frame. The transmitter 3602 may also send an SBP termination frame to the second communication device to terminate the SBP process, or the receiver 3604 may also receive an SBP termination frame from the second communication device to terminate the SBP process, and the frame body of the SBP termination frame is carried in the payload field of the fourth data frame. The first communication device and one or more third communication devices may be non-AP STAs, and the second communication device may be an AP. The first communication device and the second communication device may be non-AP STAs, and each of the one or more third communication devices may be an AP STA or a non-AP STA. The transmitter 3602 may also send an SBP Ack frame to the second communication device to confirm reception of the SBP response frame, the SBP report frame, or the SBP termination frame, the frame body of the SBP Ack frame being carried in the payload field of the fifth data frame.

[0173] Each of the first data frame and the second data frame may be an Ethernet type 89-0d data frame. The payload field of the first data frame and the payload field of the second data frame may be a 1905.1 message. The request frame may identify the second communication device in the address 3 (A3) field of the data frame carrying the frame body of the request frame. The request frame or the report frame may identify the second communication device in the MAC address field of the SBP responder carried in the 1905.1 message.

[0174] In addition, the communication device 3600 may be a second communication device. The receiver 3604 may receive a request frame from the first communication device to perform measurements on one or more links of the second communication device, the one or more links being attached to one or more third communication devices. The circuit 3614 may perform the measurements. The transmitter 3602 may send a report frame carrying one or more reports of measurements corresponding to the one or more links, wherein the frame body of the request frame is carried in the payload field of the first data frame, and the frame body of the report frame is carried in the payload field of the second data frame.

[0175] The second communication device may be an AP, and the first data frame or the second data frame may be an IEEE 802.11 data frame or an IEEE 802.15.4 data frame. The second communication device may be a non-AP STA, and the transmitter 3602 may also send an indication that the second communication device can act as an SBP responder separately from an indication that the second communication device can act as an SBP initiator. The transmitter 3602 may also send a request to the fourth communication device to perform measurements on one or more links of the fourth communication device, each of which is attached to one or more third communication devices. Each of the first data frame and the second data frame may be an Ethernet type 89-0d data frame, or the payload field of the first data frame and the payload field of the second frame are 1905.1 messages. The request frame may be an SBP request frame, and the transmitter 3602 may also send an SBP Ack frame to the first communication device to confirm the receipt of the SBP request frame, the frame body of the SBP Ack frame being carried in the payload field of the fifth data frame. The report frame may be an SBP report frame, and the transmitter 3602 may further retransmit the SBP report frame if an SBP Ack frame acknowledging reception of the SBP report frame is not received from the first communication device within a specified timeout duration.

[0176] The present disclosure can be implemented by software, hardware, or software in collaboration with hardware. Each functional block used in the description of each of the above embodiments can be partially or entirely implemented by an LSI such as an integrated circuit, and each process described in each embodiment can be partially or entirely controlled by the same LSI or a combination of LSIs. The LSI can be formed as a chip alone, or a chip can be formed to include a part or all of the functional blocks. The LSI may include data input and output coupled thereto. According to the difference in integration, the LSI here may be referred to as an IC, a system LSI, a super LSI, or an ultra LSI. However, the technology for implementing the integrated circuit is not limited to the LSI, and can be implemented by using a dedicated circuit, a general-purpose processor, or a dedicated processor. In addition, an FPGA (field programmable gate array) that can be programmed after the LSI is manufactured or a reconfigurable processor that can reconfigure the connection and setting of the circuit unit arranged inside the LSI can be used. The present disclosure can be implemented as digital processing or analog processing. If, as a result of the advancement of semiconductor technology or other derivative technologies, future integrated circuit technology replaces LSI, future integrated circuit technology can be used to integrate the functional blocks. Biotechnology can also be applied.

[0177] The present disclosure may be implemented by any kind of apparatus, device, or system having a communication function, which is referred to as a communication device.

[0178] Some non-limiting examples of such communication devices include phones (e.g., cellular (cell) phones, smart phones), tablets, personal computers (PCs) (e.g., laptops, desktops, netbooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices), game consoles, digital book readers, telemedicine / telemedicine (remote health and medicine) devices, and vehicles providing communication capabilities (e.g., cars, airplanes, ships), and various combinations thereof.

[0179] Communication devices are not limited to portable or transportable, and may also include any kind of apparatus, device, or system that is non-portable or fixed, such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines, and any other “things” in a network of the “Internet of Things (IoT)”.

[0180] Communications may include exchanging data via, for example, cellular systems, wireless LAN systems, satellite systems, etc., and various combinations thereof.

[0181] The communication device may include a device such as a controller or a sensor, which is coupled to the communication device that performs the communication functions described in the present disclosure. For example, the communication device may include a controller or a sensor that generates a control signal or a data signal used by the communication device that performs the communication functions of the communication device.

[0182] Communications equipment may also include infrastructure facilities such as base stations, access points, and any other device, equipment, or system that communicates with or controls devices such as those in the above non-limiting examples.

[0183] A non-limiting example of a station may be a station included in a first plurality of stations attached to a multi-link station logical entity (i.e., such as an MLD), wherein as part of the first plurality of stations attached to the multi-link station logical entity, the stations in the first plurality of stations share a common medium access control (MAC) data service interface to an upper layer, wherein the common MAC data service interface is associated with a common MAC address or traffic identifier (TID).

[0184] Therefore, it can be seen that the present embodiment provides a communication device and method for tunnel sensing by a proxy.

[0185] Although exemplary embodiments have been presented in the foregoing detailed description of the present embodiment, it should be understood that there are a large number of variations. It should also be understood that the exemplary embodiments are examples and are not intended to limit the scope, applicability, operation or configuration of the present disclosure in any way. On the contrary, the foregoing detailed description will provide a convenient roadmap for implementing the exemplary embodiments for those skilled in the art, and it should be understood that various changes may be made to the functions and arrangements of the steps and operating methods described in the exemplary embodiments and the modules and structures of the devices described in the exemplary embodiments without departing from the scope of the subject matter set forth in the appended claims.

Claims

1. A first communication device, comprising: circuitry that generates a request frame to request a second communication device to perform measurements on one or more links of the second communication device, each of the one or more links being attached to one or more third communication devices; A transmitter, sending the request frame to the second communication device; and A receiver receives a report frame from the second communication device, the report frame carrying one or more reports corresponding to the measurements of the one or more links, wherein the frame body of the request frame is carried in the payload field of the first data frame and the frame body of the report frame is carried in the payload field of the second data frame.

2. The first communication device according to claim 1, wherein: The request frame is a proxy sensing (SBP) setup request frame, and the first data frame or the second data frame is an IEEE 802.11 data frame or an IEEE 802.15.4 data frame.

3. The first communication device according to claim 1, wherein: The measurement is a sensing measurement and the report frame is a SBP report frame.

4. The first communication device according to claim 2, wherein: The receiver also receives an SBP setup response frame indicating whether the SBP setup request is accepted, the frame body of the SBP setup response frame being carried in a payload field of a third data frame.

5. The first communication device according to claim 1, wherein: The transmitter further transmits an SBP termination frame to the second communication device to terminate the SBP process, or the receiver further receives the SBP termination frame from the second communication device to terminate the SBP process, the frame body of the SBP termination frame being carried in a payload field of a fourth data frame.

6. The first communication device according to claim 2, wherein: The first communication device and the one or more third communication devices are non-access point AP stations STA, and the second communication device is an AP.

7. The first communication device according to claim 2, wherein: The first communication device and the second communication device are non-access point AP stations STA, and each of the one or more third communication devices is an AP STA or a non-AP STA.

8. The first communication device according to claim 1, wherein: Each of the first data frame and the second data frame is an Ethernet type 89-0d data frame.

9. The first communication device of claim 1, wherein the payload field of the first data frame and the payload field of the second data frame are 1905.1 messages.

10. The first communication device according to claim 8 or 9, wherein: The request frame identifies the second communication device in an Address 3 (A3) field of the data frame carrying the frame body of the request frame.

11. The first communication device according to claim 9, wherein: The request frame or the report frame identifies the second communication device in a MAC address field carried in the 1905.1 message.

12. The first communication device according to claim 3, 4 or 5, wherein: The transmitter also transmits an SBP confirmation (Ack) frame to the second communication device to confirm reception of the SBP response frame, the SBP report frame or the SBP termination frame, the frame body of the SBP Ack frame being carried in a payload field of a fifth data frame.

13. A second communication device, comprising: a receiver that receives a request frame from a first communication device to perform measurements on one or more links of the second communication device, the one or more links being attached to one or more third communication devices; a circuit for performing said measurement; and A transmitter sends a report frame, the report frame carrying one or more reports of the measurements corresponding to the one or more links, wherein the frame body of the request frame is carried in a payload field of a first data frame and the frame body of the report frame is carried in a payload field of a second data frame.

14. The second communication device according to claim 13, wherein: The second communication device is an AP, and the first data frame or the second data frame is an IEEE 802.11 data frame or an IEEE 802.15.4 data frame.

15. The second communication device according to claim 13, wherein: The second communication device is a non-AP STA, and the transmitter further transmits an indication that the second communication device is capable of being an SBP responder separately from the indication that the second communication device is capable of being an SBP initiator.

16. The second communication device according to claim 14, wherein: The transmitter also sends a request to a fourth communication device to perform measurements on one or more links of the fourth communication device, each of the one or more links being attached to the one or more third communication devices.

17. The second communication device according to claim 13, wherein: Each of the first data frame and the second data frame is an Ethernet type 89-0d data frame, or the payload field of the first data frame and the payload field of the second data frame are 1905.1 messages.

18. The second communication device according to claim 13, wherein: The request frame is an SBP request frame, and the transmitter further sends an SBP Ack frame to the first communication device to confirm reception of the SBP request frame, a frame body of the SBP Ack frame being carried in a payload field of a fifth data frame.

19. The second communication device according to claim 13, wherein: The report frame is an SBP report frame, and the transmitter further retransmits the SBP report frame if an SBP Ack frame acknowledging receipt of the SBP report frame is not received from the first communication device within a specified timeout duration.

20. A communication method, comprising: generating, by a first communication device, a request frame to request a second communication device to perform measurements on one or more links of the second communication device, each of the one or more links being attached to one or more third communication devices; sending the request frame to the second communication device; and A report frame is received from the second communication device, the report frame carrying one or more reports corresponding to the measurements of the one or more links, respectively, wherein a frame body of the request frame is carried in a payload field of a first data frame and a frame body of the report frame is carried in a payload field of a second data frame.

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