Communication device and communication method for wireless local area network sensing

Abstract

The present disclosure provides a communications apparatus and method for wireless local area network sensing, the communications apparatus including: a transmitter that, in operation, transmits a request frame to one or more peer communications devices, the request frame carrying transmission parameters to be used by each of the one or more peer communications devices to transmit physical layer protocol data units (PPDUs) used for channel measurement; a sensing module configured to perform channel measurements based on respective PPDU(s) received from the one or more peer communications devices; and an interface configured to obtain the sensing parameters from an upper layer application and pass results of the channel measurements to the upper layer application.

Description

Technical Field

[0001] The present disclosure relates to a communication device and method for wireless local area network (WLAN) sensing, and more particularly, to a communication device and method for WLAN sensing in the presence of various types (revised) of 802.11 devices.

Background Art

[0002] WLAN sensing is the use of received WLAN signals by a WLAN-sensing capable communication device to detect characteristics of a target (s) of interest in a given environment. In particular, examples of characteristics for WLAN sensing include range, speed, angle, movement, presence of proximity, gesture, people counting, etc., examples of targets for WLAN sensing include objects, humans, animals, etc., and examples of environments include rooms, homes, cars, enterprises, etc. The differentiating factor of WLAN sensing compared to other similar applications is that the target does not need to have a WLAN or any other wireless device. In other words, WLAN sensing functions even if the target is not aware of the sensing / detection being performed.

[0003] Currently, there are several examples of use cases that utilize WLAN sensing, such as smart homes, gesture recognition, game control, home / car presence and proximity detection, liveliness, in-store location tracking, and audio (follow-me sound) with user tracking.

[0004] Two categories of 802.11 devices are conceivable. (i) Mainstream 802.11 devices that operate in a frequency band below 7 GHz, such as high throughput (HT), very high throughput (VHT), and high efficiency (HE). These typically perform WLAN sensing by conducting channel measurements and are suitable for use cases that do not require high-resolution sensing. And (ii) Millimeter-wave 802.11 devices that operate in a frequency band above 60 GHz, such as digital multi-gigabit (DMG) and enhanced digital multi-gigabit (EDMG), where a single device can perform high-resolution sensing in a monostatic manner (similar to radar).

[0005] Regarding mainstream 802.11 devices, WLAN sensing applications typically involve conducting channel measurements, tracking one or more wireless links over time, and classifying channel variations into events or activities. Channel State Information (CSI) is a common channel measurement parameter for WLAN sensing because it provides information on how a wireless signal propagates through the channel with various effects such as time delay, amplitude attenuation, and phase shift on each subcarrier. However, existing WLAN devices do not provide a standardized interface for upper-layer applications to obtain CSI or to configure the parameters used for channel measurements.

[0006] In particular, the IEEE802.11 Project Authorization Request (PAR) states that the new Task Group (TG) 802.11bf formed for WLAN sensing will be a modification of the media access control (MAC) in the frequency band below 7 GHz, that is, there is no change in the physical layer. Legacy 802.11 devices can support the features of 802.11bf using the existing hardware by performing firmware / software updates. In other words, when the 802.11bf specification is released, 802.11n, 802.11ac, 802.11ax, 802.11az and 802.11be devices are likely to be used in the market.

[0007] It is important to investigate the issues when 11bf is implemented in various 802.11 modifications and whether WLAN sensing can be performed even on 802.11 devices that do not implement 11bf. Therefore, there is a need for a communication device and method that provide a feasible technical solution for WLAN sensing in the context of a mixture of various types (modifications) of 802.11 devices. Further, other desirable features and characteristics will become apparent from the following detailed description and the appended claims, which are to be construed in conjunction with the accompanying drawings and the background of this disclosure.

Summary of the Invention

Problems to be Solved by the Invention

[0008] Non-limiting and exemplary embodiments facilitate providing a communication device and a communication method for wireless local area network (WLAN) sensing across various 802.11 devices.

Means for Solving the Problems

[0009] In the first embodiment, the present disclosure provides a communication device including a transmitter that transmits a request frame to one or more peer communication devices during operation, where the request frame carries transmission parameters used by each of the one or more peer communication devices to transmit a physical layer protocol data unit (PPDU) used for channel measurement; a sensing module configured to perform channel measurement based on each received PPDU (singular or plural) from the one or more peer communication devices; and an interface configured to obtain sensing parameters from an upper layer application and pass the results of the channel measurement to the upper layer application.

[0010] In the second embodiment, the present disclosure provides a peer communication device including a receiver that receives a request frame including transmission parameters from a communication device during operation, and a transmitter that transmits a physical layer protocol data unit (PPDU) used for channel measurement during operation, where the PPDU applies the transmission parameters.

[0011] In the third embodiment, the present disclosure provides a peer communication device including a transmitter that periodically transmits an unsolicited sounding PPDU used for channel measurement during operation.

[0012] In the fourth embodiment, the present disclosure provides a communication method including the steps of obtaining sensing parameters from an upper layer application; transmitting a request frame to one or more peer communication devices, where the request frame carries transmission parameters used by each of the one or more peer communication devices to transmit a physical layer protocol data unit (PPDU) used for channel measurement; performing channel measurement based on each received PPDU (singular or plural) from the one or more peer communication devices; and passing the results of the channel measurement to the upper layer application.

[0013] Note that a general embodiment or a specific embodiment can be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any optional combination thereof.

[0014] Further benefits and advantages of the disclosed embodiments will become apparent from the specification and the drawings. These benefits and / or advantages can be obtained individually by various embodiments and features of the specification and the drawings, which do not all need to be provided in order to obtain one or more of such benefits and / or advantages.

[0015] The embodiments of the present disclosure will be better understood and readily apparent to those of ordinary skill in the art from the following written description, taken in conjunction with the drawings, which are by way of illustration only.

Brief Description of the Drawings

[0016]

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Embodiments for Carrying Out the Invention

[0017] Those skilled in the art will recognize that the elements in the drawings are shown for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some elements in the figures, block diagrams, or flowcharts may be exaggerated relative to other elements to assist in the accurate understanding of the present embodiment.

[0018] Some embodiments of the present disclosure are described by way of example only with reference to the drawings. Like reference numerals and letters in the drawings refer to like elements or equivalents.

[0019] In the following paragraphs, an exemplary embodiment will be described in relation to an access point (AP) and a station (STA) for a wireless local area network (WLAN).

[0020] In the context of IEEE 802.11 (Wi-Fi) technology, a station is interchangeably referred to as an STA and is a communication device having the ability to use the 802.11 protocol. Based on the definition of IEEE 802.11-2016, an STA is any device including an IEEE 802.11-compliant medium access control (MAC) and physical layer (PHY) interface to a wireless medium (WM).

[0021] For example, an STA can be a laptop, a desktop personal computer (PC), a personal digital assistant (PDA), an access point, or a Wi-Fi phone in a wireless local area network (WLAN) environment. An STA can be either fixed or mobile. In a WLAN environment, the terms "STA", "wireless client", "user", "user device", and "node" are often used interchangeably.

[0022] Similarly, an AP can be interchangeably referred to as a wireless access point (WAP) in the context of IEEE 802.11 (Wi-Fi) technology and is a communication device that enables an STA within a WLAN to connect to a wired network. An AP typically connects to a router as a stand-alone device (via a wired network), but can also be integrated with or used within a router.

[0023] As described above, a STA within a WLAN can act as an AP at different times, and vice versa. This is because in the context of IEEE802.11 (Wi-Fi) technology, a communication device can include both STA hardware components and AP hardware components. In this way, the communication device can switch between the STA mode and the AP mode based on the actual WLAN conditions and / or requirements. In the various embodiments below, the term "STA" is used to refer to a communication device that can be implemented as a sensing initiator (requester), a sensing responder, a sensing transmitter, and / or a sensing receiver.

[0024] In WLAN sensing, a sensing initiator can be a STA (or an AP) that transmits a Null Data Packet (NDP) request frame to claim an NDP from another STA (or another AP) for channel measurement, while a sensing responder can be another STA (or another AP) that receives the NDP request frame and transmits the NDP to the sensing initiator. Next, the sensing initiator performs channel measurement based on the NDP frame, and the channel measurement result (e.g., channel state information) is used for WLAN sensing. In the various embodiments below, WLAN sensing is performed without a STA transmitting an NDP request frame to claim an NDP from another STA for channel measurement. Instead, one STA transmits an NDP to another STA, and the other STA that receives the NDP performs channel measurement based on the NDP.

[0025] In the following various embodiments, the term "null data packet" or "NDP" may be used interchangeably with the term "sounding physical layer protocol data unit (PPDU)" or "response PPDU". The term "spatial stream" may be used interchangeably with the term "spatiotemporal stream". The terms "802.11n", "802.11ac", "802.11ax", "802.11az", "802.11be", and "802.11bf" may be used as "11n", "11ac", "11ax", "11az", "11be", and "11bf", respectively.

[0026] Figure 1 shows a flow diagram depicting a conventional WLAN sensing procedure 100 between a STA (STA1) 102 as a sensing requester with different sounding capabilities and two other STAs (STA2, STA3) 104, 106 as sensing responders. Each responder determines the transmission parameters of its sounding PPDU based on its own considerations, for example, based on the capabilities of itself and / or the requester, the current transmission configuration, etc. A contention-based channel access procedure, such as an Enhanced Distributed Channel Access (EDCA) procedure, is indicated by block 108, and short interframe spacings (SIFS) 111, 115 are shown. The sensing requester 102 transmits a non-high-throughput (non-HT) physical layer protocol data unit (PPDU) carrying a request frame to request respective null data packets (NDPs) from the sensing responders 104, 106. The request frame carries the identifiers (e.g., Association Identifier (AID) or MAC address) of the sensing responders 104 and 106, and the order of the identifiers determines the order in which the sensing responders transmit the NDPs. After the last symbol of the non-HT PPDU is transmitted, SIFS 111 becomes valid, and at 112, STA2 104 transmits an HT NDP 114 through two spatial streams based on the capabilities of STA1 102, in this case 11ax + 11bf, and its own sounding capabilities (e.g., STA2 104 only supports two spatial streams and can only transmit HT NDPs), in this case 11n + 11bf. After the last symbol of the HT NDP 114 is transmitted, SIFS 115 becomes valid, and at 116, STA3 106 transmits a HE NDP based on the capabilities of STA1 102 and its own sounding capabilities, in this case 11ax + 11bf (e.g., both STA1 102 and STA3 106 support four spatial streams and are both 11ax devices, and thus can transmit / receive HE NDPs).

[0027] However, this conventional WLAN sensing procedure can lead to channel measurement contradictions and errors in WLAN sensing. For example, although WLAN sensing may be machine learning trained using HT NDP, HE NDP (e.g., received from STA106) can provide significantly different channel measurements during actual deployment.

[0028] To address such issues of different device capabilities, the 11bf specification can define that the transmission parameters for the sounding PPDU are based on values that are receivable by all devices participating in the measurement. Thus, even if only one participating device is an HT device, the NDP format of all participating devices is restricted to HT PPDU, or the number of spatial streams used for NDP transmission is restricted to the minimum number of spatial streams among all participating devices, etc. However, such constraints limit the potential of WLAN sensing.

[0029] FIG. 2 shows a configuration example of a communication device 200 according to various embodiments. The communication device 200 can be implemented as a sensing requester or a sensing responder in accordance with the present disclosure and configured for WLAN sensing. As shown in FIG. 2, the communication device can include at least one wireless transmitter 204, at least one wireless receiver 206, and at least one antenna 202 (for the sake of simplicity, only one antenna is shown in FIG. 2 for illustrative purposes). At least one transmission signal generator 208 can generate a request frame to one or more peer communication devices (other STAs), and the request frame carries the transmission parameters used by each of the one or more peer communication devices to transmit a PPDU for channel measurement. At least one wireless transmitter 206 transmits the generated request frame to one or more peer communication devices.

[0030] At least one wireless receiver 204 may receive a PPDU from each of one or more peer communication devices. The communication device 200 may further include a sensing module 210 configured to perform channel measurements based on each of the respective PPDU(s) received from one or more peer communication devices, and an interface 212 configured to obtain sensing parameters from an upper layer application 214 and pass the results of the channel measurements to the upper layer application 214. The sensing module 210 also communicates with a transmission signal generator to pass the sensing parameters obtained from the upper layer application (e.g., to determine the transmission parameters to include in an NDP request frame).

[0031] FIG. 3 shows a flow diagram illustrating a communication method 300 according to the present disclosure. At step 302, a step of obtaining sensing parameters from an upper layer application is performed. At step 304, a step of transmitting a request frame to one or more peer communication devices is performed. The request frame carries the transmission parameters used by each of the one or more peer communication devices to transmit a PPDU for channel measurement. At step 306, a step of performing channel measurements based on each of the respective PPDU(s) received from one or more peer communication devices is performed. At step 308, a step of passing the results of the channel measurements to the upper layer application is performed.

[0032] According to the present disclosure, two modes of channel measurements for WLAN sensing are proposed. (i) Solicited channel measurement in which an 11bf-capable STA requests another STA to transmit a sounding PPDU. The requester specifies the transmission parameters of the sounding PPDU, such as the format of the PPDU (e.g., HT NDP, VHT NDP, or HE NDP), as well as the transmission power of the requester and the target received signal strength indicator (RSSI), bandwidth, number of spatial streams, etc. And (ii) Unsolicited channel measurement in which an 11bf-capable STA periodically transmits an unsolicited sounding PPDU. The solicited / unsolicited sounding PPDUs are used by 11bf STA(s) / device(s) to perform channel measurements that are further used for WLAN sensing.

[0033] In various embodiments, an 11bf-capable device that requests another device to sound a channel may be referred to as a WLAN sensing requester / initiator. An 11bf-capable device that responds to a sensing request to sound the channel of another device may be referred to as a WLAN sensing responder. A WLAN sensing transmitter is a device that transmits a sounding PPDU (solicited or unsolicited). In the case of solicited, this may be the same as the WLAN sensing responder. A device that performs channel measurements based on the received sounding PPDU is a WLAN sensing receiver. In the case of solicited, this may be the same as the WLAN sensing requester / initiator.

[0034] According to one embodiment, an 11bf device advertises its WLAN sensing capability in an extended capability element such as a capability bit within a frame as shown in Table 1, for example. In particular, the capability bit indicates that the 11bf device can be (i) a sensing requester, i.e., a device that can request another device to send a sounding PPDU and provide channel measurement results to an upper layer application, (ii) a sensing responder, i.e., a device that can act as a WLAN sensing responder and send a sounding PPDU(s) (e.g., NDP) in response to a request, (iii) a SENS channel measurement, i.e., a device that can perform channel measurements for WLAN sensing and provide the results to an upper layer, and (iv) unsolicited sounding, i.e., a device that can provide periodic transmission of sounding frames in an unsolicited manner. [Table 1]

[0035] FIG. 4 shows a network architecture 400 including two basic service sets (BSSs) 402, 404 according to an embodiment. The first BSS (BSS1) 402 includes an AP (AP-1) 406 and two STAs (STA1, STA-2) 408, 410, where AP1 406 and STA-2 410 are 11bf compliant devices and STA1 408 is not. The second BSS (BSS2) 404 includes an AP (AP-2) 414 and an STA (STA-3) 412, and both AP-2 414 and STA-3 412 are 11bf compliant devices. In one embodiment, in beacon frames, probe response frames, fast initial link setup (FILS) discovery frames, etc., transmitted by APs such as 406, 414, capability bits related to the sensing ability of 11bf devices may be carried. In another embodiment, in probe request frames, association request frames transmitted by non-AP STAs such as 408, 410, 412, capability bits related to the sensing ability of 11bf devices may be carried. In yet another embodiment, in other unicast frame exchanges, capability bits related to the sensing ability of 11bf devices may be exchanged.

[0036] According to various embodiments, an 11bf-capable AP advertises its WLAN sensing operation parameters, for example, in a WLAN sensing operation element. FIG. 5 shows an example format of a WLAN sensing operation element 500. The WLAN sensing operation element 500 may include an element identifier (ID) field, a length field, an element ID extension field, a solicited sounding information field 502, and an unsolicited sounding information field 504. The solicited sounding information field 502 includes sub-fields related to solicited sounding transmission (TX) parameters such as the maximum value supported by the response PPDU for the solicited sounding PPDU: channel bandwidth, number of spatial streams, and transmission power, etc. On the other hand, the unsolicited sounding information field includes sub-fields related to unsolicited sounding periodicity, unsolicited sounding PPDU format, and unsolicited sounding TX parameters such as channel bandwidth, number of streams, TX power, etc. for the unsolicited sounding PPDU.

[0037] According to the present disclosure, before actual WLAN sensing begins, an initial setup can be performed, and two or more sensing-capable devices can form a group (hereinafter referred to as a "sensing group"). In the simplest case, the sensing group includes only two devices. The sensing group can be formed by two devices across different BSSs. FIG. 6 shows a network architecture including two basic service sets and two sensing groups according to one embodiment. Similar to the network architecture of FIG. 4, the first BSS (BSS1) 602 includes an AP (AP-1) 606 and two STAs (STA1, STA-2) 608, 610, and the AP1 606 and STA1 610 are 11bf-compliant devices, while the STA-2 608 is not. The second BSS (BSS2) 604 includes an AP (AP-2) 614 and an STA (STA-3) 612, and both the AP-2 614 and STA-3 612 are 11bf-compliant devices. In this embodiment, after the setup of the WLAN sensing group, a sensing group 1 616 including the AP-1 606, STA1 618, and AP-2 614 and a sensing group 2 618 including the AP-1 606, AP-2 614, and STA-3 612 are formed. Once the sensing group is formed, any member of the group can perform any sensing role (such as requester / responder) based on its own and the peer STA's capabilities.

[0038] Each sensing group within the network architecture is identified by a group ID. A unique sounding group ID (SGID) or member ID can also be assigned to each member of the group within the group. The device that starts group formation, such as the STA1 702 in FIG. 7, acts as a group leader and is responsible for the assignment of the group ID and member ID. If all STAs are associated STAs, an associated identifier (AID) can be used instead. One device can be a member of multiple sensing groups.

[0039] FIG. 7 shows a flowchart illustrating the communication of WLAN sensing group setup according to an embodiment. In this embodiment, STA1 702 starts forming a sensing group with STA2 704, STA3 706, and STA4 708. At step 710, when STA1 702 sends a WLAN sensing group request including a group ID and a member ID to STA2 704, the WLAN sensing group setup can start. The group ID refers to the ID of the sensing group, while the member ID refers to the ID assigned to STA2 when STA2 accepts the group request. STA2 704 receives the sensing group request. Subsequently, at step 712, STA2 704 can accept the sensing group request and send a WLAN sensing group response with the acceptance status. Similar steps are continuously executed for other STAs such as STA3 706 and STA4 708. At step 714, STA1 702 sends a WLAN sensing group request including a group ID and a member ID to STA3 706. STA3 706 receives the sensing group request. Subsequently, at step 716, STA3 706 can accept the sensing group request and send a WLAN sensing group response with the acceptance status. At step 718, STA1 702 sends a WLAN sensing group request including a group ID and a member ID to STA4 708. STA4 708 receives the sensing group request. Subsequently, at step 720, STA4 708 can accept the sensing group request and send a WLAN sensing group response with the acceptance status. In this way, a sensing group including STA1 702, STA2 704, STA3 706, and STA4 708 is formed.

[0040] In one embodiment, the group ID + member ID can help identify a device during WLAN sensing even if the device's MAC address changes (e.g., by randomizing the MAC address). The device can also be authenticated when forming a sensing group, for example, using a pre - set password or other authentication token. For example, the requesting device can use a pre - set password as a secret key and calculate an authentication tag by performing a hash operation, e.g., authentication tag = HASH(password, requester's MAC address, salt). HASH can be any commonly used hash function such as HMAC or SHA - 256. The salt can be a different numerical value chosen by the requester each time and is included in the WLAN sensing group request frame along with the authentication tag. The device receiving the request can perform the exact same procedure to calculate its own version of the authentication tag using its own password, the requester's MAC address, and the provided salt. If the calculated authentication tag is the same as the authentication tag included in the request frame, the receiver can conclude that the requester also has access to the same password and thus has the authority to start group formation. A similar method can also be used in the reverse direction to authenticate the receiver in the WLAN sensing group response frame.

[0041] The sensing group leader can also assign a member ID to itself and advertise it to the group, which can be a fixed value (e.g., 0) known to the group members. Alternatively, the formation of the sensing group can be coordinated by a central entity (the AP or server in the DS), while multiple STAs within the group can also start group formation with different STAs (with the same group ID).

[0042] Figure 8 shows an example scenario under a network architecture of six BSSs and one sensing group. The area within the solid line 800 (with respect to the dashed line 801) represents a deployment location, for example, an office, and the dashed line 801 represents the area outside the office. In this example scenario, there are six APs and thus six BSSs represented by circles 802, 804, 806, 808, 810, and 812. Two WLAN sensing applications can be deployed for (i) presence detection and (ii) movement detection. Presence detection is used to detect the presence and / or absence of people in a conference room during business hours, and the coverage area is restricted to each room. Movement detection is used to detect the movement of people within a target area outside business hours, and the coverage area expands to the entire office area 800.

[0043] For the presence detection application running in each conference room, since the coverage area is restricted to each conference room, it can be assumed that all sensing devices (inside the conference room) are part of the same BSS (for example, BSS802 including AP-1 and STA-1 in Room 1, BSS806 including AP-3 and STA-3 in Room 2, BSS812 including AP-6 and STA-6 in Room 3), so the formation of a sensing group (across different BSSs) may not be necessary. However, for the movement detection application, since the coverage area is large, multiple BSSs can be grouped and formed as part of the same sensing group. In this example, since the coverage area is expanded to cover the entire office, a sensing group including all six BSSs 802, 804, 806, 808, 810, and 812 can be formed. All 11bf-compliant devices (within the six BSSs 802, 804, 806, 808, 810, and 812) within the office can be part of the security sensing group, but the AP-x 814 and STA-x 816 outside the office are not. The above is based on the assumption that all APs are within the coverage of at least one central AP (for example, AP-2 or AP-5), and for STAs outside the coverage of the central AP, the group formation process can be relayed by the edge APs.

[0044] In this example, both WLAN sensing applications can be executed on a centralized server. Each SENS (sensing) device capable of channel measurement (e.g., all APs) uploads the results of channel measurement (e.g., CSI values) to the server, such as the server in FIG. 26B, and this is processed by each WLAN sensing application (e.g., using various machine learning techniques) to extract relevant results (e.g., presence / absence, human movement, etc.).

[0045] For example, two public action frames are defined as the WLAN sensing group request frame and the WLAN sensing group response frame used for the initial setup and formation of the WLAN sensing group in FIG. 8. FIG. 9 shows an example of the WLAN sensing group request frame 900 and an example of the WLAN sensing group response frame 906 for WLAN sensing group setup. The public action frame is a Class 1 frame and can be used to communicate with non-associated STAs. The category fields 902, 908 are set to 4 (public action) in the public action frame. The public action field, which is the field immediately following the category fields 902, 908, is used to distinguish various types of public action frames. For example, the public action field value 46 is defined to indicate a WLAN sensing group request, and the public action field value 47 is defined to indicate a WLAN sensing group response.

[0046] The public action frames 900, 906 may include a frame control field, a duration field, three address fields, a sequence control field, an HT control field, a category field (or public action field) 902, 908, a dialog token field, and a frame check sequence (FCS) field. The frame control field, the duration field, the three address fields, the sequence control field, and the HT control field may be grouped as a MAC header, while the category field (or public action field) 902, 908 and the dialog token field may be grouped below the frame body. Depending on the category field or public action field value that defines its function for WLAN sensing group formation, the frame body of the public action frames 900, 906 may include additional fields. For example, if the category field 902 has a value of 4 (public action) and the public action field has a value of 46 indicating a WLAN sensing group request, the public action frame 900 functions as a WLAN sensing group request frame and may further include a WLAN sensing group request field, a group / member information field, and a WLAN sensing capability field in the frame body. The group / member information field may include a group ID subfield and a member ID assigned to the recipient of the WLAN sensing group request frame 900 if the recipient accepts the group request. The request frame may also indicate the nominal periodicity of the channel measurement exchange, i.e., the frequency at which group members are expected to participate in channel measurements (e.g., by transmitting one sounding PPDU every 20 microseconds). The recipient may reject the group formation request if it cannot respond to the request (e.g., because the channel measurement requests are too frequent).

[0047] On the other hand, when the category field 902 has a value of 4 (public action) and the public action field has a value of 47 indicating a WLAN sensing group response, the public action frame 906 functions as a WLAN sensing group response frame and may further include a WLAN sensing group response field, a status (accept / reject) field, and a WLAN sensing capability field in the frame body.

[0048] In the following paragraphs, various examples related to the first embodiment of the present disclosure are described in relation to a solicited and unsolicited channel measurement sensing requester and a sensing responder that are further used for WLAN sensing.

[0049] According to the first embodiment, during solicited channel measurement (i.e., request / response exchange), the request specifies transmission parameters of the response PPDU such as the format of the response PPDU (HT NDP, VHT NDP, HE NDP, etc.), the transmission power of the requester and the target RSSI for the response PPDU, the number of spatial streams in the response PPDU, and the bandwidth of the response PPDU (less than or equal to the bandwidth of the PPDU carrying the request frame). Next, the responder transmits the response PPDU using the requested transmission parameters.

[0050] FIG. 10 shows a flow diagram 1000 illustrating communication for solicited channel measurement between a sensing requester 1002 and a sensing responder 1004 according to a first embodiment of the present disclosure. Both the sensing requester 1002 and the sensing responder 1004 are 11bf devices. A contention-based channel access procedure, such as an EDCA procedure, is indicated by block 1006. The sensing requester 1002 transmits a request frame 1008 to the sensing responder 1004, and the request frame 1008 specifies transmission parameters of a response PPDU requested for channel measurement. After the last symbol of the request frame 1008 is transmitted, the sensing responder 1004 generates a response PPDU 1010 using the requested transmission parameters and transmits the response PPDU 1010 to the sensing requester 1002 after an interval of SIFS. Subsequently, the sensing requester performs channel measurement using the response PPDU.

[0051] The sounding request frame used to claim a response PPDU for solicited channel measurement in FIG. 10 can be a control frame. FIG. 11A shows an example of a request frame 1100 for solicited channel measurement. The request frame 1100 can include a frame control field, a duration field, a recipient address (RA) field, a transmission address (TA) field, a SENS (sensing) control field, a group / member information field 1104, a requester transmit power field 1106, a sounding information field 1108, and an FCS field. The SENS control field can further include a transmission opportunity (TXOP) transfer subfield set to "0", and a joint sounding subfield also set to "0" to indicate sequential sounding. The group / member information field can further include a group ID subfield 1110 indicating a WLAN sensing group, a session ID subfield 1112 indicating a WLAN sensing session, and a member ID list subfield 1114 indicating one or more STAs for which a response is claimed. When multiple member IDs are included, the response PPDUs are transmitted sequentially with a SIFS gap between each response PPDU, and the STA transmits in the order in which its ID appears in the list.

[0052] The requester transmission power field 1106 indicates the transmission power used for the request frame. In particular, the requester transmission power subfield 1106 indicates the transmission power (TX_Power) used for the request frame, and the target RSSI field indicates the expected received power (Target_RSSI) at the requester in the non-legacy LTF of the response PPDU. If RX_RSSI is the received power at which the request frame was received (by the responder), the responder can calculate the path loss using TX_Power: PL = TX_Power - RX_RSSI. The responder can then calculate the transmission power as Target_RSSI + PL. This helps to ensure that the received power of the sounding PPDU in different instances of channel measurement remains the same or close, in order to minimize the variation of channel measurement (especially CSI amplitude).

[0053] The sounding information field 1108 indicates transmission parameters for the response PPDU and may include a sounding PPDU format subfield 1116, a stream number subfield 1118, a target RSSI subfield 1120, a bandwidth subfield 1122, a transmission configuration hold subfield, and a transmit power hold subfield 1124. Each PPDU format represented by the value of the sounding PPDU format subfield 1116 is shown in the table of FIG. 11. The stream number subfield 1118 indicates the number of spatial streams used in the response PPDU. The target RSSI subfield 1120 indicates the expected received power at the requester in the non-legacy long training field (LTF) of the response PPDU. Examples of non-legacy LTFs for HT-LTF, VHT-LTF, 1xHE-LTF with 64 subcarriers, 2xHE-LTF with 128 subcarriers, and 4xHE-LTF with 256 subcarriers are shown in FIGS. 11B - F, respectively. In the HE sounding PPDU, the 2xHE-LTF at either 8 μS or 1.6 μS GI is mandatory, while the 4xHE-LTF at 3.2 μS GI is optional. The subcarrier spacings of HT-LTF and VHT-LTF are 312.5 kHz, 312.5 kHz, and 78.125 kHz, respectively.

[0054] The transmit power hold subfield 1124 indicates that the transmit power of the response PPDU must not change during the sensing session, while "transmission configuration hold" requires that the responder not change other transmission settings of the sensing responder, such as the number of transmit antennas and / or the antennas used, and beamforming updates, etc., when transmitting the response PPDU.

[0055] Figures 12A - B show a flow diagram illustrating communication for solicited channel measurement according to the first embodiment. According to an example of the first embodiment, the HE STA requests VHT NDPs from one HE and two VHT sensing responders. Communication between the HE STA or sensing requester (STA1) 1202, the HE sensing responder (STA2) 1204, and the two VHT sensing responders (STA3, STA4) 1206, 1208 can be shown in Fig. 12A. The sensing group members, i.e., STA1 - 4, can communicate with each other, thus resulting in a total of six measured channels as correspondingly shown by the six bidirectional arrows in Fig. 12A.

[0056] For better protection, the sounding request frame 1211 can be carried in the non - HT PPDU 1212. The sounding request frame 1211 may include the IDs of STA2, STA3, and STA4 and indicates the response PPDU format as VHT. Thus, as shown in Fig. 12B, after the last symbol of the non - HT PPDU 1212 is transmitted, SIFS 1213 can become active, and the three sensing responders STA2 - 4 1204, 1206, 1208 sequentially transmit their respective VHT NDPs 1216, 1220, 1224 with SIFS gaps 1217, 1221 between the VHT NDPs, as indicated by the three arrows C21, C31, and C41 respectively. Subsequently, STA1 receives the VHT NDP and measures channels C21, C31, and C41.

[0057] Furthermore, in this example, the sensing channel measurement is initiated by STA1. However, if the responder can also perform channel measurement for WLAN sensing, this non - transmitting responder can also perform channel measurement using (unintended) sounding PPDUs, in this case VHT NDPs. The requester STA1, 1202 can also select the transmission parameters of the response PPDU so that all STAs can receive the response PPDU and perform channel measurement.

[0058] The STA can identify the transmitter (and thereby the channel) of an unintended sounding PPDU based on the information (group ID, list of member IDs) carried in the request frame. During the formation of a sensing group, the STA can record the mapping of the member IDs and MAC addresses of other STAs within the group, and the transmitter of an unsolicited PPDU can be identified based on the position of the member ID within the request frame. Since the upper layer may not recognize the member ID assigned to the STA, the STA that measures the channel based on an unintended (or unsolicited) sounding PPDU can use the mapping of the member ID to the MAC address when reporting the results of the channel measurement (identified by the MAC address) to the upper layer application.

[0059] For example, returning to FIG. 12B, STA2 1204 is an unintended recipient of the VHT NDPs 1220 and 1224 transmitted as shown by arrows C32 and C42, and can identify the transmitters of the VHT NDPs, i.e., STA3 1206 and STA4 1208, based on the information carried in the request frame 1212 respectively. In this way, if STA2 1204 can perform channel measurements, STA2 1204 can measure channels C32 and C42.

[0060] According to the present disclosure, with respect to unsolicited channel measurement, an 11bf-compliant STA can also provide unsolicited sounding as a service. For example, if there are multiple sensing initiators that request the 11bf-compliant STA to respond periodically with sounding frames, the STA can choose to transmit unsolicited sounding PPDUs periodically (e.g., once every 20 TUs).

[0061] The transmitting STA (e.g., an AP) advertises its unsolicited sounding ability, transmission periodicity, etc. in beacon frames or probe response frames. A sensing device interested in measuring the channel from the transmitting STA can join the STA's service, for example, by performing management frame exchanges. Alternatively, the transmitting STA may passively perform channel measurements without recognizing the presence of the sensing device. Such a device may be called a WLAN sensing passive receiver. In the following various embodiments, regarding unsolicited channel measurements, the device that starts transmitting a sounding PPDU can be called a WLAN sensing transmitter, while the device that receives a sounding PPDU for the purpose of channel measurement can be called a WLAN sensing receiver.

[0062] The sounding PPDU for unsolicited channel measurements must be in a format (such as 11n NDP) that can be understood by all devices joined to such a service. When the NDP is used as an unsolicited sounding frame, a CTS-to-self frame or a broadcast HT / VHT / HE NDP announcement frame not addressed to any associated STA is transmitted before the SIFS of the NDP to identify the transmitter of the NDP.

[0063] If the transmitting STA is already transmitting other frames at a certain periodicity (e.g., an HE AP that transmits FILS discovery frames every 20 μS in the 6 GHz band, or a VHT AP that transmits beacon frames every 100 ms in the 5 GHz band), the PPDU carrying such frames can be customized to be used simultaneously for unsolicited channel measurements (e.g., by carrying additional LTFs).

[0064] FIG. 13 shows a flow diagram 1300 illustrating communication for solicited channel measurement according to the first embodiment. The process for unsolicited channel measurement may begin at step 1310 when a WLAN sensing transmitter, in this case STA1 1302, advertises its sounding capabilities and transmission parameters for unsolicited sounding to WLAN sensing receivers, in this case STA2 1304, STA3 1306, and STA4 1308. Optionally, receivers such as 1304, 1308, etc. may perform unsolicited negotiation with the transmitter 1302. In this case, at step 1312, STA2 1304 transmits a request frame for unsolicited sounding including transmission parameters based on its own and the transmitter's capabilities to STA1 1302, and at step 1314, STA1 1302 then transmits a response frame accepting or rejecting the transmission parameters to STA2 1304. Subsequently, at step 1316, STA4 1308 transmits a request frame for unsolicited sounding including transmission parameters based on its own and the transmitter's capabilities to STA1 1302, and at step 1318, STA1 1302 then transmits a response frame accepting or rejecting the transmission parameters to STA4 1308. At step 1319, STA1 then determines transmission parameters for unsolicited sounding based on requests during the unsolicited sounding negotiation phase. Alternatively, the transmission parameters and transmission periodicity of the unsolicited sounding PPDU may be determined by a sensing application (e.g., running on a central server). The trigger to initiate transmission of the unsolicited sounding PPDU may also be provided by the sensing application (e.g., in the case of the motion detection application shown in FIG. 8, the unsolicited sounding PPDU may be transmitted with a periodicity of 20 μS daily outside business hours: 8 PM to 8 AM, etc.).

[0065] During unsolicited channel measurements, transmitter 1302 can transmit CTA-to-Self frames in steps 1320, 1324, 1328 and then transmit unsolicited sounding PPDUs (NDPs) to all receivers simultaneously in steps 1322, 1326, 1330 after each unsolicited sounding interval 1323. Receiver STAs STA2-4, 1304, 1306, 1308 identify transmitter 1302 of the unsolicited sounding frame using the TA address in the CTS-to-Self frame. Subsequently, each receiver performs its own channel measurement based on the received unsolicited sounding PPDU.

[0066] Note that if the transmission time of the unsolicited sounding is the same as or very close to the target beacon transmission time (TBTT) and the beacon frame is not a delivery traffic indication map (DTIM) beacon, the STA can transmit the unsolicited sounding PPDU after the SIFS of the beacon frame. Since the TA field of the beacon frame can be used to identify the transmitter of the unsolicited sounding PPDU, in such a case, a CTS-to-Self frame does not need to be transmitted. The beacon frame is usually transmitted only on the primary 20 MHz channel, but the unsolicited sounding PPDU can be transmitted with a wider bandwidth if the secondary channel shows an IDLE clear channel assessment (CCA) within the SIFS.

[0067] Similarly, if the periodicity of the sounding PPDU matches, for example, the transmission time of the FILS discovery frame in the 6 GHz band, the sounding PPDU (e.g., NDP) can be transmitted after the SIFS of the transmission end time of the FILS discovery frame. The receiver can identify the transmitter of the NDP by identifying the TA field of the FILS discovery frame.

[0068] For example, in FIG. 13, a new type of action frame is defined as an unsolicited sounding request frame and an unsolicited sounding response frame used for unsolicited sounding negotiation between a transmitter and a receiver before transmitting an unsolicited sounding PPDU. FIG. 14 shows an example of an unsolicited sounding request frame and an example of an unsolicited sounding response frame for unsolicited channel measurement. The category fields 1402, 1406 indicate a new type of action frame for WLAN sensing, while the subsequent action field indicates various types of frames used for WLAN sensing. The action field value 0 is defined to refer to an unsolicited sounding request frame, and the action field value 1 is defined to refer to an unsolicited sounding response frame.

[0069] The action frames 1400, 1404 may include a frame control field, a duration field, three address fields, a sequence control field, an HT control field, a category field (or action field) 1402, 1406, a dialog token field, and a frame check sequence (FCS) field. The frame control field, the duration field, the three address fields, the sequence control field, and the HT control field may be grouped as a MAC header, while the category field (or action field) 1402, 1406 and the dialog token field may be grouped under the frame body. Depending on the category field or action field value that defines its function for unsolicited WLAN sensing, the frame body of the action frames 1400, 1406 may include additional fields. For example, if the category field 1402 indicates WLAN sensing and the action field has a value of 0 indicating an unsolicited sounding request, the action frame 1400 functions as an unsolicited sounding request frame and may further include an unsolicited sounding request field and a requested TX parameter field in the frame body. The requested TX parameter field may include a sounding PPDU format subfield, a stream number subfield, a bandwidth subfield, and a periodicity subfield.

[0070] On the other hand, if the category field 1406 indicates WLAN sensing and the action field has a value of 1 indicating an unsolicited sounding response, the action frame 1404 may function as an unsolicited sounding response frame and may further include an unsolicited sounding response field, a status (acceptance / rejection) field, and an actual TX parameter field in the frame body. The actual TX parameter field may include a sounding PPDU format subfield, a stream number subfield, a bandwidth subfield, and a periodicity subfield.

[0071] According to the present disclosure, a new SENS NDP announcement for announcing unsolicited NDP may also be defined. FIG. 15A shows an example of a SENS announcement frame 1500 for unsolicited channel measurement. The SENS NDP announcement frame 1500 may include a frame control field, a period field, an RA field, a TA field, a sounding dialog token field, a STA information list field 1502, and an FCS field. The RA field may include a broadcast MAC address subfield. The sounding dialog token field may include a SENS subfield set to 1, an HE subfield (set to either 0 or 1), and a sounding dialog token number subfield. The STA information list field includes an AID12 subfield 1504, a broadcast subfield 1506. When the broadcast subfield 1506 is set to 1, it indicates that an unsolicited broadcast NDP follows and the recipient is not expected to return a beamforming feedback frame. When the broadcast subfield 1506 bit is set to 1, the AID12 subfield 1504 may be set to the BSS color of the (BSS) or the group ID of the (sensing group) or the session ID of the (sensing session) instead of the recipient's AID to help the receiver classify the subsequent NDP.

[0072] When the SENS NDP announcement frame uses the format of the HE NDP announcement frame (i.e., the HE bit of the sounding dialog token is also set to 1), the STA information list is 4 octets long and may also carry the transmit power used for the subsequent HE NDP. The transmit power information may be used by the receiver to normalize the received power value of the NDP to avoid fluctuations in the CSI amplitude value due to variations in the transmit power of different (unsolicited) NDPs.

[0073] Each of the 11bf receivers performs channel measurements, passes the CSI results to their respective upper-layer WLAN sensing applications, which perform further processing (smoothing, compression, etc.) on the CSI results and transfer the results to a central server via a wired communication link. One or more WLAN sensing client applications running on the server can use the integrated CSI results from multiple 11bf devices to derive application-specific results (motion, presence, etc.).

[0074] Figure 15B shows a flowchart 1502 depicting the communication between a sensing transmitter 1512 and three sensing receivers 1514, 1516, 1518 for unsolicited channel measurements according to the first embodiment. A contention-based channel access procedure, such as an EDCA procedure, is shown by block 1520, and SIFS 1523 is shown. The sensing transmitter 1512 broadcasts a SENS NDP Announcement (SENS NDPA) frame 1522 in a broadcast-like fashion (received by all three sensing receivers 1514, 1516, 1518). After the last symbol of the SENS NDPA frame 1522 is transmitted, the SIF may become active, and the sensing transmitter 1512 then broadcasts a sounding PPDU 1526, such as a VHT NDP in this case, in a broadcast-like fashion (received by all three sensing receivers 1514, 1516, 1518). Subsequently, each of the sensing receivers 1514, 1516, 1518 performs channel measurements using the sounding PPDU 1526, while using the SENS NDPA frame 1522 to identify the sensing transmitter, sensing group / session, etc.

[0075] According to various embodiments of the present disclosure, a dedicated sensing service access point (SENS-SAP) may be defined or an existing MAC layer management entity SAP (MLME-SAP) may be extended to enable an upper layer application to adjust MAC / PHY parameters related to WLAN sensing, request the MLME to start channel measurement, and the MLME to pass channel measurement information to the upper layer application.

[0076] In one embodiment, a sensing requester, such as STA1 1002 in FIG. 10, may include a MAC interface configured to obtain sensing parameters from an upper layer application. This MAC interface is a primitive for the purpose of starting a solicited channel measurement and requesting the transmission of a request frame such as 1008 to one or more sensing responders such as STA2 1004 in FIG. 10, for example, MLME-Sensing.request (responder MAC address, group IP, member ID list, session ID, sounding PPDU format, number of streams, bandwidth, request type, and NDPA information). Such a primitive is issued by the upper layer application and can be passed from the upper layer application to a sensing requester such as STA1 1002 in FIG. 10. Upon receiving the primitive, the MLME of the sensing requester may then construct a sounding request frame for transmission to one or more sensing responders. Further details regarding the parameters included in the MLME-Sensing.request() primitive (hereinafter referred to as the ".request primitive") can be found in Table 2.

[0077] In particular, with respect to the request type parameter, the term "solicited serial" means that a sounding PPDU issued by a sensing application running on, for example, STA1 1202 of FIG. 12B is required to be transmitted serially. The term "solicited joint" means that a SENS NDPA and a sounding PPDU issued by a sensing application running on, for example, STA1 of FIG. 23 are required to be transmitted together by a requester. The term "unsolicited" means that a device is required to perform channel measurements based on the received unsolicited sounding PPDU. When this option is required, fields (PPDU format, number of streams, bandwidth, etc.) included in the request frame may be omitted in the.request primitive. If the request parameter is included in the.request primitive, the request for unsolicited sensing may also trigger joining the unsolicited sounding service as shown in FIG. 13. For example, in a sensing application that requires frequent periodic reporting of channel measurements (e.g., CSI values) when using unsolicited sounding, consecutive channel measurements may be highly correlated. The.request primitive can also include a threshold such that the device reports only new CSI values whose difference from previous CSI values is greater than the threshold. If the change in the CSI value is less than the threshold, the new CSI value is not reported to the upper layer. For example, the average correlation between the new CSI and the previous CSI can be used as the threshold. A high value of the threshold indicates low correlation, and a low value indicates high correlation.

[0078] In another embodiment, a sensing requester such as STA1 1002 in FIG. 10 may include a MAC interface including another primitive, e.g., MLME-Sensing.confirm(Responder MAC address, Session ID, PPDU format, Bandwidth, Channel matrix type, NumberOfSubcarriers_Ns, NumberOfColumns_Nc, NumberOfReceiveChains_Nr, NumberOfBitsPerElement_Nb, ChannelMatrix, SNRList), for the purpose of reporting the results of (solicited / unsolicited) channel measurements. Such a primitive is generated by a sensing requester such as STA1 1002 upon reception of a sounding PPDU such as 1010 from the sensing responder 1004 in FIG. 10 and issued by the sensing requester such as STA1 1002 to its upper layer application. Further details regarding the parameters included in the MLME-Sensing.confirm() primitive (hereinafter referred to as the ".confirm primitive") can be found in Table 3.

[0079] In particular, when the channel measurement is based on a compressed / uncompressed feedback frame received from a legacy STA, a channel matrix type other than CSI may be used (this is described in more detail in the sixth embodiment and FIGS. 25A - B). When the channel measurement is performed by the requester / receiving STA itself based on a sounding PPDU, the CSI channel matrix type may be used as the default option. As previously explained, if the.request primitive includes a threshold, the device only generates a.confirm primitive to report a new CSI value whose difference from the previous CSI value is greater than the threshold. If the change in the CSI value is less than the threshold, the.confirm primitive is not generated.

[0080] In yet another embodiment, for unsolicited channel measurements, a primitive, such as MLME-Unsolicited-Sounding.request(PPDU format, bandwidth, number of streams, SoundingPeriod), which aims to request a sensing transmitter such as STA1 1302 in FIG. 13 to start periodic unsolicited sounding to the MLME, may be included in the MAC interface. Such a primitive is issued by a higher layer application to a sensing transmitter such as STA1 1302 in FIG. 13. Upon receiving the primitive, the MLME of the sensing transmitter generates a periodic command to the PHY to transmit a sounding PPDU once every SoundingPeriod (by issuing a PHY-TXSTART.request primitive). Further details about the parameters included in the MLME-Unsolicited-Sounding.request() primitive can be found in Table 4.

[0081] According to various embodiments of the present disclosure, a dedicated sensing physical layer management entity (SENSE-PLME-SAP) may be defined or an existing PLME-SAP may be extended to enable the MLME to adjust PHY parameters related to WLAN sensing and the PLME to pass information related to the received sounding frame to the MLME.

[0082] In one embodiment, a sensing requester such as STA1 1002 in FIG. 10 may include a PHY interface including a primitive, e.g., PLME-Configure-ChannelMatrixType.request(CHAN_MAT_TYPE), for the purpose of configuring a desired channel matrix type to be used by the sensing requester to report the result of channel measurement to the MAC layer. Such a PLME primitive may be issued by the MAC layer of the sensing requester such as STA1 1002 in FIG. 10 to its PHY. When the PLME primitive is received by the PHY, the PLME configures the PHY to report the CHAN_MAT parameter of the RXVECTOR with the requested channel matrix type. The PLME also sets the CHAN_MAT_TYPE parameter of the RXVECTOR to the requested channel matrix type. Further details regarding the parameter CHAN_MAT_TYPE included in the PLME primitive can be found in Table 5.

[0083] In the following paragraphs, a second embodiment of the present disclosure is described in relation to a sensing requester and a sensing responder for solicited channel measurement that are further used for WLAN sensing.

[0084] According to the second embodiment of the present disclosure, the format and bandwidth of the response PPDU are implicitly indicated by the format of the PPDU that carries the request frame. In this embodiment, the requesting STA uses the same PPDU format and bandwidth as that requested from the response PPDU to carry the request frame. The responding STA uses the same PPDU format and bandwidth as that used to carry the request frame for the response PPDU. Note that in this embodiment, by using a PPDU format other than non-HT as the initial PPDU of the TXOP, there may be a risk that a third-party STA cannot correctly receive the initial PPDU, and thus cannot set the Network Allocation Vector (NAV) used to protect the TXOP, and a request-to-send / clear-to-send (RTS / CTS) frame exchange carried by a non-HT / non-HT duplicate PPDU is required to protect subsequent PPDU exchanges.

[0085] FIG. 16A shows a flow diagram 1600 illustrating communication between a sensing requester and a sensing responder for solicited channel measurement according to the second embodiment of the present disclosure.

[0086] A contention-based channel access procedure, such as an EDCA procedure, is indicated by block 1605. The sensing requester 1602 transmits an RTS frame 1606 carried in a non-HT PPDU to the sensing responder 1604. Subsequently, the sensing responder 1604 transmits a CTS frame 1608 carried in a non-HT PPDU to the sensing requester 1602. In this example, after the RTS / CTS frame exchange, the sensing requester 1602 transmits a 20 MHz HT PPDU carrying a request frame 1610 to the sensing responder 1604. Subsequently, the sensing responder 1604 transmits a response PPDU 1612 (20 MHz HT PPDU) under the same format and bandwidth as that of the PPDU carrying the request frame 1610. The sensing requester 1602 performs channel measurement using the received 20 MHz HT response PPDU 1612.

[0087] FIG. 16B shows another flow diagram 1620 illustrating communication between a sensing requester and a sensing responder for solicited channel measurement according to a second embodiment of the present disclosure.

[0088] A contention-based channel access procedure, such as an EDCA procedure, is indicated by block 1625. Sensing requester 1622 transmits two RTS frames 1626, 1627 carried in a 40 MHz non-HT duplicate PPDU to sensing responder 1624 together. Subsequently, sensing responder 1624 transmits two CTS frames 1628, 1629 carried in a 40 MHz non-HT duplicate PPDU to sensing requester 1622 together. Similarly, in this example, after the RTS / CTS frame exchange, sensing requester 1622 transmits a 40 MHz HE PPDU carrying a request frame 1630 to sensing responder 1624. Subsequently, sensing responder 1624 transmits a response PPDU 1632 (40 MHz HE PPDU) under the same format and bandwidth as that of the PPDU carrying request frame 1630. Sensing requester 1624 performs channel measurement using the received 40 MHz HE response PPDU.

[0089] In the following paragraphs, a third embodiment of the present disclosure is described in relation to a sensing requester and a sensing responder for solicited channel measurement that are further used for WLAN sensing.

[0090] According to the third embodiment of the present disclosure, the transmission parameters of the response PPDU are negotiated between the sensing requester and one or more sensing responders during the setup phase of the WLAN sensing session and remain the same throughout the WLAN sensing session. FIG. 17 shows a flow diagram 1700 illustrating communication for sensing session negotiation and solicited channel measurement according to the third embodiment of the present disclosure. The process for sensing session negotiation may begin at step 1708 when a WLAN sensing requester, in this case STA1 1702, transmits a sensing session request frame including a session ID and transmission parameters for subsequent solicited channel measurement to a first sensing receiver, in this case STA2 1704. At step 1710, the first sensing receiver 1704 then transmits a sensing session response frame including a status indicating acceptance or rejection of the request. Subsequently, at step 1712, the sensing requester 1702 transmits a sensing session request frame including a session ID and transmission parameters to a second sensing receiver, in this case STA3 1705. Similarly, at step 1714, the second sensing receiver 1705 then transmits a sensing session response including a status indicating acceptance or rejection of the request. Subsequently, the same steps of transmitting a sensing session request frame including a session ID and transmission parameters from the sensing requester 1702 to a third sensing receiver STA4 1706 and transmitting a sensing session response frame indicating acceptance or rejection of the request from the third sensing receiver 1706 to the sensing requester are executed at steps 1716 and 1718, respectively. The STA that accepts the session request saves the session ID and the corresponding TX parameters. In this way, the process for sensing session negotiation may be completed.

[0091] According to this embodiment, during the sensing session negotiation phase, parameters such as the session ID and transmission parameters accepted by the sensing receivers, in this case 1704 - 1706, are used for subsequent solicited channel measurements and remain the same throughout the WLAN sensing session. In particular, following the sensing session negotiation phase, the process for solicited channel measurements can begin when, at step 1720, the sensing requester 1702 simultaneously transmits a sounding request frame containing the session ID to all sensing receivers 1704 - 1706. SIFS can be enabled. As shown in steps 1722, 1724, 1726, the sensing receivers 1704 - 1706 then sequentially transmit their respective sounding PPDUs using the stored TX parameters with a gap of SIFS between the sounding PPDUs. Subsequently, a second solicited channel measurement can be performed within the sensing session. The process for the second solicited channel measurement can begin when, at step 1728, the sensing requester 1702 again simultaneously transmits another sounding request frame containing the same session ID to all sensing receivers 1704 - 1706. SIFS can be enabled. As shown in steps 1730, 1732, 1734, the sensing receivers 1704 - 1706 then again sequentially transmit their respective sounding PPDUs using the stored TX parameters with a gap of SIFS between the sounding PPDUs.

[0092] According to the third embodiment, for example, two public action frames are defined as a WLAN sensing session request frame and a WLAN sensing session response frame used for WLAN sensing session negotiation in FIG. 17. FIG. 18 shows an example of a WLAN sensing session request frame 1800, an example of a WLAN sensing session response frame 1804, and an example of a sounding request frame 1808 according to the third embodiment. The public action frame is a class 1 frame and can be used to communicate with non-associated STAs. When the category fields 1802, 1806 indicate a public action frame, the public action field value 48 is defined to indicate a WLAN sensing session request, and the public action field value 49 is defined to indicate a WLAN sensing session response.

[0093] The public action frames 1800, 1804 may include a frame control field, a duration field, three address fields, a sequence control field, an HT control field, a category field (or public action field) 902, 908, a dialog token field, and a frame check sequence (FCS) field. The frame control field, the duration field, the three address fields, the sequence control field, and the HT control field may be grouped as a MAC header, while the category fields 1802, 1806, the public action field, and the dialog token field, etc. may be grouped below the frame body. Depending on the category field or public action field value that defines its function for WLAN sensing group formation, the frame body of the public action frames 1800, 1806 may include additional fields. In this embodiment, when the public action field has a value of 48 that indicates a WLAN sensing session request, the public action frame 1800 functions as a WLAN sensing session request frame and may further include a WLAN session request field, a group / member information field, a session ID field, and a response transmission parameter field in the frame body. The group / member information field includes a group ID subfield and a member ID subfield. The response transmission parameter field may include a sounding PPDU format subfield, a stream number subfield, a target RSSI subfield, a bandwidth subfield, a transmission configuration hold subfield, and a transmission power hold subfield.

[0094] On the other hand, when the public action field has a value of 49 that indicates a WLAN sensing session response, the public action frame 1806 functions as a WLAN sensing session response frame and may further include a WLAN sensing session response field and a status (acceptance / rejection) field in the frame body.

[0095] For example, the sounding request frame 1808 used for solicited channel measurement after a sensing session negotiation in FIG. 17 may be a simplified version of the request frame 1100 in FIG. 11A, and may include a frame control field, a period field, an RA field, a TA field, a group / member information field, a session ID field, and an FCS field. The group / member information may include a group ID subfield and a member ID list subfield. Although not shown in FIG. 18, the sounding request frame 1808 may also carry a sounding control field.

[0096] In the following paragraphs, a fourth embodiment of the present disclosure is described in relation to a sensing requester and a sensing responder for solicited channel measurement further used for WLAN sensing.

[0097] According to the present disclosure, for example, by using a new variation of the HE trigger frame for WLAN sensing to request and using HE trigger-based (TB) ranging NDP (defined in IEEE 802.11az) transmitted on non-overlapping 20 MHz channels to respond, it is possible to claim response PPDUs from multiple sensing responders using orthogonal frequency division multiple access (OFDMA). Note that this is different from the HE TB ranging NDP transmitted over the entire bandwidth body using different spatial streams in 802.11az. Furthermore, HE TB PPDUs that do not carry a data field may also be utilized to achieve such multi-user sounding. Such HE TB PPDUs may be referred to as HE TB sensing NDP.

[0098] FIG. 19 shows a flow diagram illustrating communication for solicited channel measurements from multiple sensing responders using OFDMA according to a fourth embodiment of the present disclosure. A contention-based channel access procedure, such as an EDCA procedure, is shown by block 1910, and SIFS 1913 is shown. A sensing requester 1902 simultaneously transmits a trigger frame 1912 to three sensing responders (STA2, STA3, STA4) 1904, 1906, 1908. In this example, the request frame 1912 requests one 40 MHz sounding PPDU from STA2 1904, one 20 MHz sounding PPDU from STA3 1906, and one 20 MHz sounding PPDU from STA4 1908. After the last symbol of the trigger frame 1912 is transmitted, SIFS 1913 can become active, and at 1914, the sensing responder 1904 transmits a 40 MHz HE TB ranging NDP 1916a in the first and second 20 MHz subchannels of the 80 MHz frequency segment, the sensing responder 1906 transmits a 20 MHz HE TB ranging NDP 1916b in the third 20 MHz subchannel of the 80 MHz frequency segment, the sensing responder 1908 transmits a 20 MHz HE TB ranging NDP 1916c in the fourth 20 MHz subchannel of the 80 MHz frequency segment, and the three HE TB ranging PPDUs 1916a - c are all transmitted simultaneously to the sensing requester 1902 on non-overlapping 20 MHz subchannels using OFDMA. Subsequently, the sensing requester 1902 performs channel measurements of the sensing responders 1904 - 1908 using the HE TB ranging PPDUs 1916a - c, respectively.

[0099] According to the fourth embodiment of the present disclosure, a new variation of the HE trigger frame for WLAN sensing is defined and used to solicit response PPDUs from multiple responders using OFDMA. FIG. 20 shows an example of a sensing trigger frame used as the trigger frame 1902 of FIG. 19, for example, to solicit response PPDUs from multiple responders using OFDMA according to the fourth embodiment. The sensing trigger frame includes a frame control field, a duration field, an RA field, a TA field, a common information field 2002, a user information list field 2004, a padding field, and an FCS field. The common field 2002 further includes a trigger type field 2006 and a trigger-dependent common information field 2008. The trigger type field indicates a new trigger type variant for sensing. The trigger-dependent common information 2008 further includes a group ID subfield indicating a WLAN sensing group, a stream number field indicating the number of spatio-temporal streams used for the response PPDU, and a transmission configuration hold subfield.

[0100] The user information list field 2004 further includes an AID12 / SGID field, an RU allocation field 2014 indicating the resource units used for the response PPDU, a spatial stream (SS: Spatial Stream) allocation field, and an uplink (UL: Uplink) target RSSI field.

[0101] In the following paragraphs, the fifth embodiment of the present disclosure is described in relation to cooperative channel measurements further used for WLAN sensing.

[0102] In use cases where many channels need to be measured (e.g., motion / presence detection for security), a WLAN sensing STA may coordinate channel measurements to reduce the overhead of channel measurements. In such an embodiment, a sensing requester may transfer an unused portion of a transmission opportunity (TXOP) to another sensing requester to have its own WLAN sensing performed. Such cooperative channel measurements are useful when only a subset of 11bf devices can perform channel measurements and / or when channel measurements based on unintended sounding PPDUs (slide 16) are not desired.

[0103] Figures 21A - B show a flow diagram illustrating communication for cooperative channel measurements according to the fifth embodiment. In this embodiment, members of a sensing group, i.e., STA1 - 4, can communicate with each other, thus resulting in a total of six channels being measured, as correspondingly shown by the six bidirectional arrows in Figure 21A.

[0104] As shown in FIG. 21B, a contention-based channel access procedure, e.g., an EDCA procedure, is indicated by block 2111, and SIFS2113, 2117, 2122, 2129, 2133, 2137, 2141, 2146, 2149 are indicated. Similar to the solicited channel measurement in FIG. 12B, STA1 2102 transmits a request frame 2112 to three STAs, namely STA2 2104, STA3 2106, and STA4 2108. The request frame 2112 may specify the IDs of STA3 and STA4 and the transmission parameters used by the response PPDU. After the last symbol of the request frame 2112 is transmitted, SIFS2113 may become valid, and all three STAs, STA2, STA3, and STA4, may sequentially transmit their respective response PPDUs 2116, 2120, 2124 with gaps of SIFS2117, 2121 between the response PPDUs 2116, 2120, 2124, as indicated by the three arrows C21, C31, C41 respectively. STA1 then measures channels C21, C31, and C41 using the response PPDUs 2116, 2120, 2124 received from STA2, STA3, and STA4 respectively.

[0105] Subsequently, if there is an unused portion of TXOP2110, STA1 2102 may transmit a SENS start request frame 2128 to transfer the unused portion (or the remaining period) of TXOP2110 to STA2. As a result, STA2 may then act as a sensing requester and transmit a request frame 2132 to STA3 and STA4 to request response PPDUs for channel measurement. The request frame 2132 may specify the IDs of STA2, STA3, STA4 and the transmission parameters used by the response PPDU. After the last symbol of the request frame 2132 is transmitted, SIFS may become valid, and both STA3 and STA4 may sequentially transmit their respective response PPDUs 2136, 2140 with a gap of SIFS2137 between the response PPDUs 2136, 2140, as indicated by the two arrows C32, C42 respectively. STA2 then correspondingly measures channels C32 and C42 using the response PPDUs 2136, 2140 received from STA3 and STA4.

[0106] Similarly, if there is still an unused portion of TXOP2110, STA2 2104 can then send a SENS start request frame 2144 to transfer the unused portion (or remaining period) of TXOP2110 to STA3. As a result, STA3 can then act as a sensing requester and send a request frame 2148 to STA4 to request a response PPDU for channel measurement. The request frame 2148 can specify the ID of STA4 and the transmission parameters used by the response PPDU. After the last symbol of the request frame 2148 is transmitted, SIFS can become active, STA4 can send a response PPDU2152 as indicated by arrow C43, and STA3 can then measure channel C43 using the response PPDU2152 received from STA4. In this way, it is advantageous that channel measurements of all six channels can be performed with a single TXOP.

[0107] For example, a variation of the sounding request frame from that of FIG. 11A is defined and used as a SENS start request frame to request another 11bf device to start its channel measurement. FIG. 22 shows an example of a SENS start request frame 2200 for cooperative channel measurement. The SENS start request frame 2200 includes a frame control field, a duration field 2202, an RA field, a TA field and a SENS control field 2204, a group / member information field 2206 and an FCS field. The duration field indicates the remaining TXOP period. The SENS control field 2204 includes a TXOP transfer field set to 1 to indicate a new variation of the sounding request frame, and joint sounding set to 0. The group / member information field 2206 includes a group ID field, a session ID field and a member ID list field 2208. In this example, the group / member information can indicate the group ID or session ID of the current channel measurement, while the member ID list field 2208 is preliminary.

[0108] Alternatively, if TXOP transfer control is also defined for data frames (e.g., in multi-AP coordinated TDMA (C-TDMA: Coordinated TDMA)), one bit in the frame can be used to distinguish the frame for use in TXOP transfer for sounding. In this case, the TXOP recipient AP uses the remaining TXOP for sounding.

[0109] According to another example of the fifth embodiment for cooperative channel measurement, instead of serially sounding channels for measurement, two or more WLAN sensing transmitters can sound channels simultaneously in a joint manner. In particular, one sensing transmitter starts joint sounding by transmitting a SENS request trigger frame to one or more transmitters. Two or more sensing transmitters transmit SENS NDPAs simultaneously (after SIFS for transmission / reception of the SENS request trigger frame). The sensing transmitters transmit sounding PPDUs simultaneously (after SIFS for transmission of the SENS NDPA).

[0110] FIG. 23 shows a flowchart showing communication for joint sounding and cooperative channel measurement according to the fifth embodiment. A contention-based channel access procedure, such as an EDCA procedure, is shown by block 2310. A sensing transmitter, such as sensing transmitter 1 2302, starts joint sounding by transmitting a SENS request trigger frame 2312 to one or more sensing transmitters, such as sensing transmitter 2 2304. After the last symbol of the SENS request trigger frame such as 2312 is transmitted, SIFS 2313 can become valid, and two or more transmitters, such as sensing transmitter 1 2302 and sensing transmitter 2 2304, simultaneously transmit their respective SENS NDPA frames 2316, 2318 to sensing receivers, such as sensing receiver 1 2306 and sensing receiver 2 2308.

[0111] After the last symbol of the SENS NDPA frame is transmitted, SIFS 2319 can become active, and two or more transmitters 2302, 2304 can simultaneously transmit their respective (joint) sounding PPDUs, in this case VHT NDPs 2322, 2324, to sensing receivers 2306, 2308. Subsequently, sensing receivers 2306 and 2308 perform channel measurements (of the aggregated channel) using the received sounding PPDUs.

[0112] This example is based on the assumption that the transmitting transmitters can maintain tight synchronization (time, CFO). This mode can be called "joint sensing" and can be useful for use cases that require channel measurements involving multiple transmitters and receivers, such as detecting human movement throughout an office as in the case of FIG. 8. Performing joint sounding, instead of performing channel measurements serially one channel at a time (e.g., T1 to R1, T1 to R2, T2 to R1, T2 to R2), can help reduce the airtime overhead of WLAN sensing. The same SENS NDPA frame is transmitted by all transmitters. The next NDP can also be the same, or the non-legacy LTF tone groups of the NDP can be orthogonally coded. When an HE PPDU is used for SENS NDPA and NDP, the BSS_Color parameter (HE SIG-A1) of the PHY header is set to 0.

[0113] Variations of the sounding request frame from, for example, that of FIG. 11A are defined and used as SENS request trigger frames to request another 11bf device to perform joint sounding. FIG. 24 shows an example of a SENS request trigger frame 2400 for joint sounding and cooperative channel measurement. The SENS request trigger frame 2400 includes a frame control field, a duration field, an RA field, a TA field and a SENS control field, a group / member information field, a requested transmit power field, sounding information, an NDPA information field 2402 and an FCS field.

[0114] When multiple transmitters are addressed, the RA field is set to the broadcast MAC address; otherwise, it is set to the RA of the other transmitter participating in the joint sounding. The SENS control field includes a TXOP transfer field set to 0 and a joint sounding field 2401 set to 1 to indicate joint sounding. The group / member information field 2206 includes a group ID field, a session ID field, and a member ID list field. The group ID field indicates the group ID associated with the sensing group if it exists; otherwise, the group ID field is reserved. When multiple transmitters are addressed, the "list of member IDs" field indicates the member IDs of the transmitters participating in the joint sounding. The requester transmit power field indicates the transmit power used for the joint sounding PPDU.

[0115] The sounding information field indicates information for the joint sounding PPDU and includes a sounding PPDU format field, a stream number field, a target RSSI field, a bandwidth field, a transmit configuration hold field, and a transmit power hold field. The target RSSI field is reserved for joint sounding.

[0116] When the joint sounding field 2401 is set to 1, the NDPA information field 2402 exists. The NDPA information field 2402 includes a TA field 2404, as well as a sounding dialog token number field 2406 and an AID12 field 2408, which carry information used for subsequent NDPA frames such as 2410 transmitted by all sensing transmitters (the same as SENS NDPA2316 and 2318 in Figure 23).

[0117] In particular, the SENS NDP announcement frame 2410 for joint sounding includes a frame control field, a period field, an RA field 2412, a TA field 2414, a sounding dialog token, an STA information list field 2416, and an FCS field. The sounding dialog token field further includes a SENS field set to 0, a HE field set to either 0 or 1, and a sounding dialog token number field 2418. The STA information list field 2416 further includes an AID12 field and a broadcast field set to 1. When the sensing transmitter that transmits the request frame 2400 also participates in the transmission of the sounding PPDU, the TA field 2404 is set as the MAC address of the sensing transmitter, and otherwise it can be set to one of the other sensing transmitters.

[0118] The TA field 2414, the sounding dialog token number field 2418, and the AID12 field 2420 of the SNES NDPA frame 2410 can correspond to the TA field 2404, the sounding dialog token number field 2406, and the AID12 field 2408 of the SENS request trigger frame 2400, as indicated by the arrows 2418, 2420, 2422.

[0119] In the following paragraphs, a sixth embodiment of the present disclosure is described in relation to cooperative channel measurement further used for WLAN sensing.

[0120] According to the sixth embodiment of the present disclosure, the 11bf-capable STA may also be able to perform WLAN sensing with a non-11bf device that does not support WLAN sensing capabilities. This can be achieved by (i) performing channel measurements based on passively listening for beacons and data frames transmitted by the non-11bf device, (ii) having the non-11bf device sound the channel for other purposes, such as implicit beamforming feedback (.11n), TB sounding for ranging (.11az), etc., and performing channel measurements based on the received sounding frames, or (iii) inducing (compressed / uncompressed) beamforming feedback (.11n, 11ac, 11ax) and using the feedback as the result of channel measurements. The mode of WLAN sensing with this non-11bf device may be restricted to 802.11 STAs that are part of the same BSS. Such a non-11bf device may be referred to as a non-WLAN sensing responder. Other WLAN sensing passive receivers that can listen for channel measurement exchanges may also perform opportunistic WLAN sensing using sounding frames or beamforming feedback frames.

[0121] FIG. 25A shows a flowchart illustrating communication between an 802.11bf compliant STA and a non-802.11bf compliant STA for WLAN sensing. In this example, an 11bf compliant 11n STA1 as a sensing requester 2502 causes another 11n STA2 (not 11bf compliant) as a sensing responder 2504 to sound the channel (via implicit beamforming) and measure the channel using a sounding PPDU. A contention-based channel access procedure, such as an EDCA procedure, is shown by block 2506. The sensing requester 2502 transmits an HT frame 2508 to the non-11bf compliant sensing responder 2504. The HT frame 2508 has its Training Request (TRQ) bit set to 1 to request the responder to transmit a sounding PPDU. After the last symbol of the HT frame 2508 is transmitted, the sensing responder 2504 then transmits an HT sounding PPDU 2510 to the sensing requester 2502 after an SIFS. Subsequently, the sensing requester 2502 performs channel measurements based on the received HT sounding PPDU 2510.

[0122] Figure 25B shows a flowchart depicting communication between an 802.11bf-compliant STA for WLAN sensing and two non-802.11bf-compliant STAs. In this example, the 11bf-compliant 11ac STA1 as the sensing requester 2522 sounds the channel (via explicit beamforming) and collects compressed beamforming feedback from two 11ax (non-11bf-compliant) STAs, e.g., STA2 2524 and STA3 2526, and uses the beamforming feedback as the result of channel measurement. A contention-based channel access procedure, e.g., the EDCA procedure, is indicated by block 2528. The sensing requester 2522 simultaneously transmits a VHT announcement frame 2530 to the non-11bf-compliant sensing responders 2524, 2526. After the last symbol of the VHT announcement frame 2530 is transmitted, SIFS may become active, and then the sensing requester 2502 simultaneously transmits a VHT NDP 2534 to the sensing responders 2524, 2526. After the last symbol of the VHT NDP 2534 is transmitted, SIFS may become active, and then sensing responder 1 2524 transmits a VHT compressed beamforming frame 2538 to the sensing requester 2522 after SIFS. The sensing requester 2522 uses the feedback from sensing responder 1 2524, i.e., the VHT compressed beamforming frame 2538, as the result of the channel measurement of sensing responder 1 2524.

[0123] After the last symbol of the VHT compressed beamforming frame 2538 is transmitted, SIFS may become active, and the sensing requester 2522 may then send a beamforming reporting pole 2542 to the sensing responder 2 2526. After the last symbol of the beamforming reporting pole 2542 is transmitted, the sensing responder 2 2526 may then send a VHT compressed beamforming frame 2456 after SIFS. The sensing requester 2522 uses the feedback from the sensing responder 2 2526, i.e., the VHT compressed beamforming frame 2538, as the result of the channel measurement of the sensing responder 2 2526.

[0124] In one embodiment, a sensing requester such as the STA1 2502, 2522 of FIGS. 25A and 25B may include a MAC interface that includes primitives for the purpose of starting legacy channel measurement procedures, such as MLME-Legacy-Sensing.request (responder MAC address, feedback type, STA information list, bandwidth, channel matrix type). Such primitives may be issued by a higher layer application and passed from the higher layer application to a sensing requester such as the STA1 2502, 2522 to trigger an implicit beamforming feedback as shown in FIG. 25A or an explicit beamforming feedback as shown in FIG. 25B. Upon receiving the primitive, the MLME of the sensing requester starts an implicit or explicit beamforming feedback sequence in the requested format. The results of the channel measurement are passed to the higher layer application using the MLME-Sensing.confirm primitive. Further details about the parameters included in the MLME-Legacy-Sensing.request() primitive can be found in Table 6.

[0125] FIG. 26A shows a configuration example of a communication device 2600 that can be implemented as a sensing requester, or a sensing receiver or a sensing transmitter, in accordance with the present disclosure and configured for WLAN sensing. The communication device may include at least one antenna 2602 for transmitting and receiving signals (only one antenna is shown in FIG. 26A for simplicity). The communication device may include a MAC sublayer 2606 and a PHY sublayer 2610. Both the MAC and PHY layers include respective management entities called a MAC sublayer management entity (MLME) 2614 and a PHY sublayer management entity (PLME) 2630. These entities provide layer management service interfaces such as a SENSE service access point (SAP) 2612 and an MLME-PLME SAP 2616, through which primitives defined therein are exchanged and information is passed, and layer management functions such as WLAN sensing can be invoked. In this example, a dedicated SENSE-PLME-SAP 2618 can be defined and used to exchange primitives between the MLME and the PLME, or an existing PLME-SAP can be extended for the same function and purpose. The MLME 2614 may further include a sensing module 2615 configured to perform channel measurements.

[0126] The communication device further includes a station management entity (SME) that is a layer-dependent entity that performs functions in place of a general system management entity and implements a standard management protocol to ensure correct MAC operation. The layer-dependent entity 2626 provides interfaces such as an MLME SAP 2622 and a PLME SAP 2624 for exchanging primitives and communicating with the MLME and the PLME, respectively.

[0127] The communication device includes upper layer applications such as the WLAN sensing application 2628. The upper layer application communicates with the MLME by exchanging primitives through a dedicated SENSE SAP2612 interface or an existing MLME-SAP extended for the same function and purpose.

[0128] For channel measurement, the upper layer application may request the MLME2614 to start channel measurement through the SENSE SAP2612, for example, using the MLME-Sensing.request primitive. The information included in the request can be found in Tables 2, 4, and 6 for solicited channel measurement, unsolicited channel measurement, and solicited legacy channel measurement, respectively. The MLME2614 can pass information or PHY parameters related to WLAN sensing to the PLME through the MLME-PLME SAP2616 and the SENSE-PLME SAP2618 for the PHY sublayer 2610 to form a physical layer protocol data unit (PPDU), such as a sounding PPDU (NDP), a request frame, or an announcement frame including a PPDU. The PPDU is then transmitted to one or more peer communication devices through the antenna 2602 via at least one wireless transmitter (not shown).

[0129] When a response PPDU, such as a response PPDU, a sounding PPDU, or an NDP, is received from one or more peer communication devices, the PPDU is unpacked at the PHY sublayer 2610, and the information related to the received PPDU is passed from the PLME2630 to the MLME2614 through the SENSE-PLME SAP2618. The sensing module 2615 can then perform channel measurement based on the information of the received PPDU. Subsequently, the MLME2614 can notify the WLAN sensing application 2628 of the result of the channel measurement through the MLME SAP2622 via the SME2626 or directly through the SENSE SAP2612. The information included in the notification to the SME can be found in Table 3.

[0130] In a simple use case / deployment, the entire WLAN sensing platform can be implemented in a single communication device. FIG. 26B shows another configuration example of a communication device 2600 with the entire WLAN sensing platform 2634 implemented therein according to the present disclosure. This communication device 2630 may include at least one antenna 2632 for transmitting and receiving signals (only one antenna is shown in FIG. 26B for simplicity). Similar to the communication device 2600 of FIG. 26A, the communication device 2630 includes an 802.11 MAC / PHY sublayer 2636 including a sensing module 2639 for channel measurement, layer management service interfaces such as an MLME SAP 2640 and a MAC SAP 2638 where primitives defined for passing information are exchanged and layer management functions such as WLAN sensing can be called, and an upper layer application (e.g., a WLAN sensing application) 2642 that communicates with the 802.11 MAC / PHY 2636 through the MLME SAP 2640.

[0131] Furthermore, the 802.11 MAC / PHY sublayer 2636 can communicate with a WLAN data application 2644 through the MAC SAP 2638 and the MLME SAP 2640. In this example, the sensing module 2639 performs channel measurement and provides raw results to the WLAN sensing application 2642 via the WLAN sensing API. The WLAN sensing application 2642 collects and integrates channel measurement results from the 802.11 device, processes the results (e.g., smoothes, compresses), and then can pass the processed results to WLAN sensing client applications such as 2646 and 2648. WLAN sensing client applications such as 2646 and 2648 perform WLAN sensing based on the channel measurement (e.g., using application-specific machine learning algorithms, etc.) and provide the results of WLAN sensing, in this case human presence / absence detection and human movement detection.

[0132] In more complex use cases or larger-scale deployments, the WLAN sensing platform can be implemented at a central location (e.g., a central server) using the channel measurement results of multiple 802.11 devices. FIG. 26C shows another configuration example of a plurality of communication devices 2660, 2662 in which the WLAN sensing platform according to the present disclosure is implemented at a central location. Similar to the communication device 2630 in FIG. 26B, each communication device such as 2660, 2662 includes an 802.11 MAC / PHY sublayer including a sensing module for channel measurement, layer management service interfaces such as MLME SAP and MAC SAP through which primitives defined for passing information are exchanged and layer management functions such as WLAN sensing can be called, and upper layer applications (e.g., WLAN sensing applications and WLAN data applications) that communicate with 802.11 MAC / PHY 2636 through MLME SAP and / or MAC SAP.

[0133] The sensing module of each of the communication devices 2660, 2662 can perform channel measurements and provide the raw results to their respective WLAN sensing applications. The WLAN sensing applications then collect and integrate the channel measurement results from their respective 802.11 MAC / PHY sublayers, process the results (e.g., smooth, compress, etc.), and pass the processed results to the central server 2664.

[0134] The channel measurement results are passed through the switch / router 2664 to the client server 2668 and one or more client modules 2666 running on the client server. Next, WLAN sensing applications such as 2670, 2672 of the client module 2666 perform WLAN sensing based on the channel measurement results received by the client server 2668 (e.g., using application-specific ML algorithms, etc.) and provide the results of the WLAN sensing (presence / absence, human movement, etc.).

[0135] As described above, embodiments of the present disclosure provide an advanced communication system, communication method, and communication apparatus for WLAN sensing across various 802.11 devices.

[0136] The present disclosure can be implemented by software, hardware, or software cooperating with hardware. Each functional block used in the description of each of the above-described embodiments can be implemented, in part or in whole, by an LSI such as an integrated circuit, and each process described in each embodiment can be controlled, in part or in whole, by the same LSI or a combination of LSIs. The LSI can be formed individually as a chip, or one chip can be formed to include part or all of the functional blocks. The LSI can include a data input / output section coupled thereto. Here, the LSI can be referred to as an IC, system LSI, super LSI, or ultra LSI depending on the degree of integration. However, the technology for implementing the integrated circuit is not limited to the LSI and can be realized by using an application-specific circuit, a general-purpose processor, or a dedicated processor. In addition, an FPGA (Field Programmable Gate Array) that can be programmed after the manufacture of the LSI, or a reconfigurable processor in which the connection and setting of circuit cells arranged inside the LSI can be reconfigured can be used. The present disclosure can be realized as digital processing or analog processing. When future integrated circuit technology replaces the LSI as a result of the progress of semiconductor technology or another derivative technology, the functional blocks can be integrated using the future integrated circuit technology. Biotechnology can also be applied.

[0137] The present disclosure can be implemented by any type of device, apparatus, or system having a communication function referred to as a communication apparatus.

[0138] A communication device may include a transceiver and processing / control circuitry. The transceiver may include a receiver and a transmitter, and / or may function as a receiver and a transmitter. The transceiver may include, as a transmitter and a receiver, an RF (radio frequency) module including an amplifier, an RF modulator / demodulator, etc., and one or more antennas.

[0139] Some non-limiting examples of such communication devices include telephones (e.g., cellular (mobile) phones, smartphones), 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, smartwatches, tracking devices), game consoles, digital book readers, telehealth / telemedicine (remote health and medical) devices, and vehicles providing communication functions (e.g., automobiles, airplanes, ships), as well as various combinations thereof.

[0140] The communication device is not limited to being portable or mobile, and may also include non-portable or stationary devices, devices or systems of any kind, such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines, and any other "things" within the network of the "Internet of Things (IoT)", etc.

[0141] Communication may include data exchange through, for example, cellular systems, wireless LAN systems, satellite systems, etc., and various combinations thereof.

[0142] The communication device may include devices such as a controller or a sensor connected to a 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 a communication device that performs the communication functions of the communication device.

[0143] The communication device may also include an infrastructure facility such as a base station, an access point, and any other device, apparatus, or system that communicates with or controls those among the above non-limiting examples.

[0144] Although some characteristics of various embodiments have been described in relation to the device, it will be understood that the corresponding characteristics also apply to the methods of the various embodiments, and vice versa.

[0145] Those skilled in the art will recognize that numerous variations and / or modifications can be made to the present disclosure as shown in the specific embodiments without departing from the spirit or scope of the present disclosure as broadly described. Accordingly, the present embodiments must be considered in all respects to be illustrative and not restrictive. [Table 2] [Table 3] [Table 4] [Table 5] [Table 6]

Claims

1. A transmitter that transmits a request frame including a session identifier for identifying a sensing session during operation and transmission parameters used by each of one or more peer communication devices to transmit a physical layer protocol data unit (PPDU) for channel measurement, to the one or more peer communication devices; A sensing module configured to perform the channel measurement based on each of the PPDU(s) received from the one or more peer communication devices; An interface configured to obtain sensing parameters from an upper layer application and pass the result of the channel measurement to the upper layer application; A communication device including the above.

2. The PPDU(s) received from the one or more peer communication devices used for channel measurement are transmitted using the same PPDU format and the same channel bandwidth as a request PPDU including the request frame. The communication device according to Claim 1.

3. The transmission parameters include a group identifier, identifiers of each of the one or more peer communication devices, and at least one of a PPDU format, a number of spatial streams, a channel bandwidth, a target received power, and a transmission power. The communication device according to Claim 1.

4. The request frame further includes a transmission power holding field for indicating to the one or more peer communication devices to transmit the PPDU(s) using the same transmission power during the sensing session. The communication device according to Claim 1.

5. The transmission parameters are negotiated with the one or more communication devices during setup of the sensing session. The communication device according to any one of Claims 1 to 4.

6. The interface includes primitives for requesting transmission of the request frame to the one or more peer communication devices and passing, from the upper layer application, a group identifier, a session identifier, identifiers of each of the one or more peer devices or a media access control address of one of the one or more peer communication devices, a PPDU format, a number of spatial streams, and a channel bandwidth. The communication device according to any one of claims 1, 2, 4, and 5.

7. The interface includes primitives for passing to the upper layer application a session identifier, a media access control address of one of the one or more peer communication devices, a PPDU format, a channel bandwidth, and a result of channel measurement. The communication device according to any one of claims 1, 2, 4, and 5.

8. The sensing module is further configured to perform channel measurement periodically based on an unsolicited PPDU received from at least one of the one or more peer communication devices. The communication device according to any one of claims 1 to 7.

9. Each of the at least one of the one or more peer communication devices is identified by a transmitter address field of a frame received immediately before the unsolicited PPDU. The communication device according to claim 8.

10. The interface includes primitives for requesting the one or more peer communication devices to initiate a legacy channel measurement procedure. The communication device according to any one of claims 1 to 9.

11. A receiver that receives, during operation, a request frame including transmission parameters and a session identifier that identifies a sensing session from a communication device; A transmitter that transmits, during operation, a physical layer protocol data unit (PPDU) used for channel measurement, the PPDU applying the transmission parameters. A peer communication device including the above.

12. The PPDU is transmitted using the same PPDU format and the same channel bandwidth as a request PPDU including the request frame. The peer communication device according to claim 11.

13. The transmission parameters include a PPDU format, a number of spatial streams, a channel bandwidth, and a target received power. The peer communication device according to claim 11 or 12.

14. Obtaining sensing parameters from an upper layer application; Transmitting, to the one or more peer communication devices, a request frame including a session identifier that identifies a sensing session and transmission parameters used by each of the one or more peer communication devices for transmitting a physical layer protocol data unit (PPDU) used for channel measurement. Performing the channel measurement based on each of the one or more received PPDUs (singular or plural) from the peer communication devices; Passing the result of the channel measurement to the upper layer application; A communication method including the above steps.

15. The request frame is a public action frame including a public action field with a first value set, The public action frame with a second value set in the public action field functions as a response frame to the request frame. The communication device according to claim 1.

16. Receiving, from a communication device, a request frame including a transmission parameter and a session identifier for identifying a sensing session; Transmitting a physical layer protocol data unit (PPDU) used for channel measurement, where the PPDU applies the transmission parameter. A communication method including the above steps.

17. A process of obtaining sensing parameters from an upper layer application; A process of transmitting, to the one or more peer communication devices, a request frame including a session identifier for identifying a sensing session and transmission parameters used by each of the one or more peer communication devices for transmitting a physical layer protocol data unit (PPDU) used for channel measurement; Performing the channel measurement based on each of the one or more received PPDUs (singular or plural) from the peer communication devices; Passing the result of the channel measurement to the upper layer application. An integrated circuit for controlling the above processes.

18. A process of receiving, from a communication device, a request frame including a transmission parameter and a session identifier for identifying a sensing session; A process of transmitting a physical layer protocol data unit (PPDU) used for channel measurement, where the PPDU applies the transmission parameter. An integrated circuit for controlling the above processes.

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