COMMUNICATION APPARATUS AND METHOD FOR OPPORTUNISTIC WLAN SENSING - Patent application

Abstract

A communication device and a communication method corresponding to opportunistic WLAN sensing are provided. An exemplary embodiment provides a first communication device, the first communication device comprising: a receiver that receives, during operation, a first PPDU and a second PPDU, where the first PPDU indicates a PHY parameter of the first PPDU and the second PPDU indicates a PHY parameter of the second PPDU, and a circuit that, during operation, compares the first PPDU with the second PPDU and determines whether the PHY parameters of the first PPDU and the second PPDU are used for sensing based on the PHY parameters of the first PPDU and the second PPDU.

Description

[Technical field]

[0001] The present embodiments relate generally to communication devices, and more particularly, to methods and apparatus supporting opportunistic wireless local area network (WLAN) sensing. [Background technology]

[0002] In the standardization of next-generation wireless local area networks (WLANs), a new radio access technology that is backward compatible with IEEE 802.11a / b / g / n / ac / ax technologies was discussed in the IEEE 802.11 Working Group and named 802.11be Extremely High Throughput (EHT) WLAN.

[0003] P802.11bf PAR defines an amendment that allows "MAC service interface for layers above MAC to request and obtain WLAN sensing measurements." WLAN sensing measurements can use Physical Protocol Data Units (PPDUs), such as null data PPDUs (NDP), for sensing.

[0004] How to efficiently perform the WLAN sensing procedure is being considered. The details to be included in the WLAN sensing procedure are still under discussion. Such details include: - How to reduce overhead, such as overhead resulting from special sequences for WLAN sensing (which also exists in threshold-based WLAN sensing) - When and how the receiver forwards channel measurements to higher layers (this is not limited to opportunistic sensing, but can also apply to NDP if special sequences dedicated to sensing (such as NDPA for sensing) are not used) - How does the receiver know the necessary transmit parameters to perform channel measurements? - How does the receiver know for which PPDU it should forward channel measurements to higher layers for opportunistic sensing? - If the PPDU is an NDP, it is possible to perform channel measurements and forward the results to the MAC, but currently this procedure is not done for non-sounding PPDUs. Therefore, how can the receiver be able to forward channel measurements to upper layers in the case of a normal PPDU (e.g., if channel measurements are performed using an NDP, there is an NDPA frame before the NDP, and the receiver forwards the channel measurement results based on this NDPA frame to the MAC, but not in the case of other PPDUs)? - How to ensure that the format and transmission parameters of regular PPDUs do not affect the channel measurement results of opportunistic WLAN sensing when changed due to channel conditions. For example, referring to diagram 600 of FIG. 6, due to beamforming 606 due to channel conditions or other factors, the channel conditions may change between the transmission of PPDU 602 and PPDU 604, which may affect the channel measurement results calculated using PPDU 602 and the channel measurement results calculated from PPDU 604. PPDUs 602 and 604 may be NDP, data frames, beacons, or other similar frames.

[0005] However, there has been no discussion of opportunistic WLAN sensing to date. [Prior art documents] [Non-patent literature]

[0006] [Non-Patent Document 1] IEEE contributions 21 / 504r1 (Specification Framework for TGbf, Claudio da Silva) [Non-Patent Document 2] 20 / 1851r4 (Overview of Wi-Fi Sensing Protocol, Cheng Chen et. al.) [Non-Patent Document 3] IEEE 802.11-21 / 1069 (Threshold-based Sensing Measurement Follow up (Huawei)) [Non-Patent Document 4] IEEE 802.11-21 / 1015 Non-TB and TB measurement procedure for WLAN Sensing. (LGE) [Non-Patent Document 5] IEEE 802.11-21 / 908 Sensing measurements: Interfaces and reporting (Intel,908) Summary of the Invention [Problem to be solved by the invention]

[0007] Therefore, what is needed is a communication apparatus and method that can solve the problems set forth above. Furthermore, other desirable features and characteristics will become apparent from the following detailed description and the appended claims, taken in conjunction with the accompanying drawings and the Background section of this disclosure.

[0008] Non-limiting and exemplary embodiments facilitate providing a communications apparatus and method that supports opportunistic WLAN sensing. [Means for solving the problem]

[0009] According to one aspect of the present disclosure, a first communications device is provided, the first communications device comprising: a receiver that, during operation, receives a first PPDU and a second PPDU, where the first PPDU indicates PHY parameters of the first PPDU and the second PPDU indicates PHY parameters of the second PPDU; and a circuit that, during operation, compares the first PPDU with the second PPDU and determines whether the PHY parameters of the first PPDU and the second PPDU are used for sensing based on the PHY parameters of the first PPDU and the second PPDU.

[0010] According to another aspect of the present disclosure, there is provided a second communications device comprising: a circuit for generating, during operation, a PPDU indicating a change in a transmission parameter; and a transmitter for transmitting, during operation, the PPDU to the first communications device such that channel measurements can be performed based on the PPDU and the indicated change in the transmission parameter.

[0011] According to another aspect of the present disclosure, there is provided a communication method including the steps of receiving a first PPDU and a second PPDU, where the first PPDU indicates a PHY parameter of the first PPDU and the second PPDU indicates a PHY parameter of the second PPDU, and comparing the first PPDU with the second PPDU and determining whether the first PPDU and the second PPDU are used for sensing based on the PHY parameters of the first PPDU and the second PPDU.

[0012] It should be noted that the general or specific embodiments may be implemented as a system, a method, an integrated circuit, a computer program, a storage medium, or any selective combination thereof. Additional benefits and advantages of the disclosed embodiments will become apparent from the specification and drawings. These benefits and / or advantages may be obtained individually by the various embodiments and features of the specification and drawings, and it is not necessary for all of the embodiments and features to be provided in order to obtain one or more of such benefits and / or advantages. [Brief description of the drawings]

[0013] The accompanying drawings, together with the following detailed description, are incorporated in and form a part of this specification, and serve to illustrate various embodiments and to explain various principles and advantages according to the present embodiments. Throughout the different drawings, like reference numbers indicate identical or functionally similar elements. [Figure 1] 1 illustrates an illustration of a WLAN sensing process using null data packets (NDP), according to an example. [Diagram 2] 1 illustrates an illustration of a High Efficiency (HE) Physical Protocol Data Unit (PPDU) frame format, according to an example. [Diagram 3] 1 illustrates an illustration of various Orthogonal Frequency Division Multiple Access (OFDMA) PPDU formats, according to an example. [Figure 4] 1 illustrates an implementation of threshold-based feedback for WLAN sensing, according to an example. [Diagram 5] 13 illustrates an implementation of threshold-based feedback for WLAN sensing according to another example. [Figure 6] 1 illustrates an illustration of a channel measurement process according to an example. [Figure 7A] FIG. 1 illustrates how WLAN sensing can be performed, according to an example. [Figure 7B] FIG. 1 illustrates how WLAN sensing can be performed, according to an example. [Figure 8] 1 shows an illustration of channel measurement using NDP, according to an example. [Figure 9] 1 illustrates an illustration of a station (STA) information field format in an EHT (Extra High Throughput) NDP announcement frame, according to an example. [Figure 10] 13 illustrates an illustration of a variant of a sensing trigger frame according to an example. [Figure 11]1 illustrates an illustration of medium access control (MAC) filtering of received PPDUs used for sensing, according to an example. [Figure 12] 1 shows an illustration of a sensing NDP according to an example. [Figure 13] 1 shows an illustration of a sensing process according to an example. [Figure 14] 13 shows an illustration of a sensing process according to another example. [Figure 15] 1 shows an illustration of opportunistic WLAN sensing in accordance with various embodiments. [Figure 16] 1 shows another illustration of opportunistic WLAN sensing in accordance with various embodiments. [Figure 17] 1 illustrates an example of how a receiver STA performs opportunistic WLAN sensing with a target STA and filters out PPDUs from other STAs according to a first embodiment. [Figure 18] 2 shows an illustration of a method for selecting a benchmark PPDU according to a first embodiment; [Figure 19] 4 shows an illustration of the operation of the sensing receiver according to the first embodiment; [Figure 20] 1 illustrates an illustration of a medium access control (MAC) primitive issued to a physical layer (PHY) to extract CSI from a target PPDU. [Figure 21] 4 shows another illustration of the operation of the sensing receiver according to the first embodiment. [Figure 22] 1 shows another illustration of a medium access control (MAC) primitive that is set by the MAC to filter a particular PPDU, such that the physical layer (PHY) automatically passes the CSI from the filtered PPDU to the MAC. [Figure 23] 1 shows an illustration of WLAN sensing using transmit beamforming sequences according to a variant of the first embodiment; [Figure 24]13 shows an illustration of WLAN sensing using ranging sequences according to another variant of the first embodiment; [Diagram 25] 1 shows an illustration of a WLAN sensing procedure according to a second embodiment. [Figure 26] 13 illustrates an illustration of opportunistic sensing support capability in a WLAN sensing capability element according to a second embodiment. [Figure 27] 13 illustrates an illustration of a Tunneled Direct Link Setup (TDLS) discovery request frame that can be used to advertise opportunistic sensing capabilities according to a second embodiment. [Figure 28] 4 shows an illustration of a sensing session according to the second embodiment. [Figure 29] 6 shows an illustration of a sensing session according to a variant of the second embodiment. [Diagram 30] 6 shows an illustration of a sensing session according to a variant of the second embodiment. [Diagram 31] 13 illustrates an example HE Link Adaptation (HLA) A-control field illustration according to a second embodiment. [Diagram 32] 6 shows an illustration of a channel measurement process adapted by a receiver to compensate for changes in transmission parameters according to a second embodiment; [Diagram 33] 13 illustrates an example WLAN Sensing Transmit (Tx) parameter indication frame diagram according to a second embodiment. [Diagram 34] 13 shows an illustration of how a transmitting STA indicates new parameters to a receiving STA according to a second embodiment; [Diagram 35] 13 shows an illustration of an exemplary threshold-based sensing procedure according to a third embodiment. [Diagram 36]13 shows an illustration of an exemplary threshold-based sensing procedure using NDP according to a third embodiment. [Figure 37] 13 illustrates an exemplary sensing type normal PPDU diagram according to the fourth embodiment. [Figure 38] 13 shows an illustration of a sensing process using periodically transmitted PPDUs according to a fifth embodiment; [Figure 39] 1 shows a schematic diagram of a receiver according to various embodiments; [Diagram 40] 1 shows a schematic diagram of a transmitter according to various embodiments. [Diagram 41] 1 shows a flow diagram illustrating a method for opportunistic WLAN sensing according to various embodiments. [Diagram 42] 1 shows a partially boxed schematic diagram of a STA that may be implemented for opportunistic WLAN sensing in accordance with various embodiments.

[0014] Skilled artisans will appreciate that elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] The following detailed description is merely exemplary in nature and is not intended to limit the embodiments or the application and uses of the embodiments. Moreover, there is no intention to be bound by the theories presented in the preceding Background or Detailed Description sections. Moreover, other desirable features and characteristics will become apparent from the following detailed description and the appended claims, taken in conjunction with the accompanying drawings and the background of this disclosure.

[0016] An overview of the WLAN sensing protocol is provided in Non-Patent Document 1 and Non-Patent Document 2. Referring to Fig. 1, an NDP 106 can be used in a WLAN sensing process 100 between a transmitter 102 and a receiver 104. The NDP 106 can be referred to as a sensing NDP.

[0017] Multiple-input multiple-output (MIMO) channel measurements are performed on every PPDU as a result of transmitting a long training field (LTF) as part of the PHY preamble. For example, referring to Figure 2, the HE-LTF field 202 of the HE PPDU frame format 200 can be used for channel measurements.

[0018] The spatial mapping matrix specifies the type of spatial mapping used in the signal. In the IEEE 802.11n / ac / ax / be[2] standard, the spatial mapping matrix is ​​sometimes referred to as the "Q matrix". There are various types of Q matrices that can be used by the transmitter in the WLAN sensing process. When an identity matrix is ​​used by the transmitter, the Q matrix is ​​known as direct allocation. In direct allocation, each space-time stream is sent to only one transmitter antenna, and there is no interference between the space-time streams. The Q matrix is ​​also known as the Fourier matrix. The Fourier matrix mixes all space-time streams to all selected antennas and is commonly used when deploying operational transmitters.

[0019] In explicit beamforming, in order for STA A to transmit a beamformed packet to STA B, STA B measures the channel metric and informs STA A of the effective channel H eff,k , or the beamforming feedback matrix V k STA A transmits one of the steering matrix Q steer,k =Q k V k Determine where Q k V kis the orthogonal spatial mapping matrix used to transmit the sounding PPDU that elicits steer,k is the Q k is defined as the mathematical term for updating the new steering matrix of

[0020] There are two types of beamforming feedback matrices: uncompressed beamforming feedback and compressed beamforming feedback. In the current specification (802.11ax), compressed beamforming feedback is implemented. The beamformer uses compressed beamforming feedback to calculate the steering matrix Q k can be determined.

[0021] The PPDU format and transmission parameters may change based on channel conditions, adjacent channel interference, etc. As shown in diagram 300 in Figure 3, 11ax itself has five different types of ODFMA HE PPDU formats, e.g., HE-Single User (HE-SU) 302, HE-Multi-User (HE-MU) 304, HE-Outdoor Single User (HE-xSU) 306, HE-Trigger Response (HE-TRIG) 308, and HE-NDP 310 for downlink channel sounding. Transmission parameters such as Q-matrix, number of LTFs in the PPDU, Modulation and Coding Scheme (MCS), and bandwidth may vary depending on the channel conditions.

[0022] Non-Patent Document 3 describes threshold-based feedback for WLAN sensing, which aims to reduce the overhead of sending feedback every time a channel measurement is performed. For example, diagram 400 in FIG. 4 shows an exemplary WLAN sensing process using threshold-based feedback with NDP 402. Although threshold-based measurement reduces the number of times explicit feedback is sent, a special sequence for WLAN sensing is still used (e.g., channel measurement needs to send NDPA 404 and NDP 402 only to check whether the threshold is exceeded, which is still overhead).

[0023] Task group TGbf on WLAN sensing has proposed several ways in which WLAN sensing can be performed, such as trigger-based (TB) sensing, non-TB sensing, and NDP-based sensing (e.g., Non-Patent Document 4). It is also possible that WLAN sensing can be performed based on a PPDU other than a normal PPDU, e.g., a PPDU dedicated for sensing, such as a sensing NDP (such a normal PPDU can be referred to as a non-sensing PPDU). With reference to Figure 3, various HE PPDU formats include a data frame and an NDP frame (e.g., HE-NDP 310). In the 802.11 specification, the LTF (e.g., the HE-LTF field in various HE PPDU formats) is defined as a long training field used for channel estimation.

[0024] There is little advantage to using NDP for WLAN sensing, but the need to transmit special frames for sensing, such as NDPA and NDP frames, adds overhead to ongoing communications. It is possible to measure the channel using normal PPDUs with minimal or no overhead, since these PPDUs are transmitted for ongoing WiFi operations. A receiver (e.g., a receiving STA or a receiver STA) may receive multiple PPDUs from a transmitter (e.g., a transmitting STA or a transmitter STA) and may unnecessarily consume system and computing resources by processing channel state information (CSI) from all received PPDUs. The receiver should also be able to filter out PPDUs that are not from STAs with which the receiver wants to perform WLAN sensing, for example, as further illustrated and described in Figures 7A and 7B.

[0025] A STA may perform channel measurement based on a normal PPDU received from another STA to check whether a threshold is exceeded. If a threshold is exceeded, the STA may perform a complete channel measurement based on the LTF in the received PPDU and send explicit feedback. For example, referring to the diagram 500 of FIG. 5, in order to further reduce the overhead of NDPA and NDP transmission for detecting whether a threshold is exceeded, WLAN sensing may be performed using non-sensing frames such as normal PPDUs 502 and 504. The CSI (i.e., the channel measured during the training symbol of the received PPDU) is a kind of sensing measurement result for sub-7 GHz WLAN sensing, as discussed in Non-Patent Document 5.

[0026] Opportunistic sensing is defined as a procedure of performing WLAN sensing using non-sensing PPDUs. WLAN sensing can be performed opportunistically by the receiver by extracting CSI from the LTF of the received PPDU and issuing a primitive to request the receiver's MAC to pass the CSI to itself. With reference to Figures 7A and 7B, STA2 704 can be configured to calculate channel measurements from the PPDU 708 received from STA1 702 and the PPDU 710 received from AP3 706, but only requests the MAC to pass the CSI results from the calculation if the Transmit Address (TA) of the frame conveyed in the PPDU matches the TA of the sensing transmitter, e.g., STA1 702 (for whom STA2 704 performs WLAN sensing 712).

[0027] In general, an NDPA frame will have an indication within the frame to inform whether the NDPA frame is a sensing NDPA frame (and therefore also indicate whether a subsequently transmitted NDP frame is a sensing NDP frame). With reference to the diagram 800 of FIG. 8, if an NDPA frame 802 is a sensing NDPA, then an NDP frame 804 is a sensing NDP. A sensing NDP frame can be transmitted following a sensing NDPA frame or in response to a sensing trigger (e.g., a variant of the sensing trigger type shown in diagram 1000 of FIG. 10). Unless the PHY is modified below 7 GHz, the sensing NDP can be in the same format as one of the existing NDPs, e.g., HT NDP, VHT NDP, HE NDP, HE ranging NDP / HE TB ranging NDP (including ranging NDP with secure HE-LTF), or EHT NDP.

[0028] FIG. 9 shows an illustration of a STA information field format 900 in an EHT NDPA frame, which may be used, for example, in the NDPA frame 802 of FIG. 8. The reserved bit 902 may be used to indicate whether the NDPA frame is a sensing NDPA. For example, the reserved bit 902 may be set to 1 to indicate that the NDPA is a sensing NDPA and the following NDP is a sensing NDP. Alternatively, a sensing trigger may be used instead of an NDPA frame, such as in the form of the sensing trigger format 1000 of FIG. 10. In the sensing trigger format 1000, a sensing trigger subtype field 1002 may be used to signal a sub-variant of the sensing trigger frame (e.g., measurement polling, sounding, etc.). For example, a trigger type subfield value of 9 (e.g., entry 1006 of table 1004) may be indicated in the sensing trigger subtype field 1002 to indicate that it is a sensing trigger frame.

[0029] The filtering of PPDUs can be further extended to (but not limited to) the PPDU format for channel measurement. The receiver can select PPDUs for which it requests channel measurement results from the PHY to the MAC. The filtering can be based on one or more of the following: - The receiver can select the minimum number of LTFs (or other PHY parameters such as bandwidth, transmit power, etc.) that must be present in a PPDU in order for the receiver's MAC to request CSI from the MAC layer. - The receiver can choose to request CSI from the MAC only for certain PPDU formats (e.g. SU-PPDU). - The receiver can choose to request CSI from the MAC only for PPDUs carrying a particular frame type (e.g. data frames).

[0030] For frames that satisfy the filtering rules of the sensing receiver, the receiver MAC can issue the PHY primitive PHY-CSI_RECEIVE.request(CSI_PARAMETER) and instruct the PHY to pass the collected sensing measurements to the MAC (e.g., in the PHY-CSI_RECEIVE.confirm(CSI_MATRIX) primitive) if the CSI is not passed to the MAC layer. The main purpose of filtering PPDUs is to solicit CSI for PPDUs from the STAs for which sensing is performed. However, this procedure is not useful if the Tx parameters are changed. To ensure that the format of the PPDU remains the same during the sensing session, the transmitter can transmit the same PPDU format during the sensing session. However, this is not an optimal solution as it affects the data transmission.

[0031] FIG. 11 shows an illustration of a MAC filtering process 1100 according to an example. In step 1102, a receiver receives a PPDU. In step 1104, the receiver checks the MAC filtering rules to select PPDUs that pass the filter for the purpose of measuring the channel. If the received PPDU does not satisfy the filtering rules, the process proceeds to step 1106, where the receiver's MAC discards the PPDU for WLAN sensing. Otherwise, if the filtering rules are satisfied, the process proceeds to step 1108, where the receiver's MAC issues a PHY primitive to request CSI from the PHY if the TA addresses match.

[0032] The problem of "how to ensure that channel measurement results are not affected when the format and transmission parameters of normal PPDUs are changed due to channel conditions in opportunistic WLAN sensing" can also be applied to the NDP for sensing, since no specific rules have been defined to ensure this condition. The IEEE specifications also contain rules for a similar purpose. It may also be necessary to apply such rules to the "NDP for sensing". For example, referring to FIG. 12, the sensing NDP can be defined as a HE sensing NDP 1200 that follows the following rules: Q matrix is ​​not applied to the waveform. The Beamformed field of the HE-SIG-A 1202 of the sensing NDP 1200 is always set to 0. In the transmission of the HE-STF 1204 and HE-LTF 1206, N STS =N TX , the Q matrix is ​​the identity matrix, and N STS <N TX In the case of , the Q matrix is ​​based on the antenna selection matrix without antenna swapping. Furthermore, if all the "0" elements are removed, the Q matrix becomes an identity matrix.

[0033] FIG. 13 shows an illustration of a sensing process 1300 according to an example. A normal PPDU 1306 transmitted from a sensing transmitter AP 1304 to a sensing receiver STA 1302 has the same Tx parameters for sensing during a sensing session, e.g., after sensing setup 1308, until sensing is terminated at 1310 (either by an explicit sensing teardown or an implicit termination rule). If an NDP is transmitted during a sensing session, the NDP may have the same Tx parameters as the normal PPDU 1306 in a first option. The sensing receiver STA 1302 may use both the normal PPDU and the NDP for sensing. In a second option, the NDP does not have the same Tx parameters as the normal PPDU 1306. The rules for the NDP may be the same as those described for the sensing NDP. The sensing receiver STA 1302 may use either the normal PPDU 1306 or the sensing NDP. Alternatively, the sensing receiver STA 1302 may use normal PPDU for sensing and NDP separately for separate sensing.

[0034] FIG. 14 shows an illustration of a sensing process 1400 according to another example. Similar to the sensing process 1300, a measurement setup ID 1412 is negotiated during the sensing setup phase 1408. The measurement setup ID 1412 can be included in a sensing setup request 1414 sent from the sensing receiver STA 1402 to the sensing transmitter AP 1404, or in a sensing setup response 1416 sent from the sensing transmitter AP 1404 to the sensing receiver STA 1402. A normal PPDU 1406 can also include the measurement setup ID in its payload, for example, in the A-control field of the MAC frame carried in the PPDU. The sensing transmitter AP 1404 shall not include a measurement setup ID having the same value as the measurement setup ID 1412 value in the normal PPDU 1406 if the Tx parameters for sensing are different. This rule allows the sensing receiver STA 1402 to recognize that a PPDU containing the same Measurement Setup ID value as the Measurement Setup ID 1412 value has the same Tx parameters for sensing.

[0035] In order to address the various problems mentioned above, various methods for opportunistic WLAN sensing are proposed. Referring to the diagram 1500 of FIG. 15, a method is proposed for the receiver STA2 1504 to perform opportunistic WLAN sensing without changing its behavior in normal WiFi operation. When the receiver STA2 1504 receives PPDUs from other STAs, it performs MAC filtering to filter out PPDUs other than PPDUs from STAs with which the receiver wants to perform WLAN sensing (e.g., PPDUs from the transmitter STA1 1502). The receiver STA2 1504 receives PPDUs of various formats during a period, selects a benchmark PPDU format (e.g., PPDU 1506), and performs WLAN sensing using PPDUs of the same format as the selected benchmark PPDU 1506 to perform consistent channel measurement. The benchmark PPDU format can be defined as the PPDU format received the maximum number of times at receiver STA2 1504 during a beacon interval or the last PPDU format received before a sensing session from a STA with which the receiver wants to perform sensing (e.g., transmitter STA1 1502). Using the filtering method proposed in SPS, PPDUs other than the benchmark PPDU can be filtered out, and the benchmark PPDU is used to extract the benchmark measurements. Information from the benchmark PPDU format, such as RSS1, Nsts, Ntx, etc. can also be stored by receiver STA2 1504.

[0036] If the received PPDU format is the same as the benchmark PPDU format (e.g., PPDU 1508), the receiver performs normalized channel measurement on the channel measurement results of the received PPDU (e.g., extract CSI from PPDU 1508) and the benchmark measurement to minimize the impact of the change in the transmission parameters. Otherwise, if the format of the received PPDU is different from that of the benchmark PPDU (e.g., PPDU 1510), the receiver does not extract CSI. In the normalized channel measurement, a subset of the matrix is ​​extracted based on the rank and order of the current channel measurement results (e.g., CSI matrix) and the benchmark channel measurement results. The rank of a matrix refers to the number of linearly independent rows or columns in the matrix. If the Q matrix is ​​provided by the receiver STA2 1504, the reverse channel can be calculated. The number of rows and columns that a matrix has is called the order or dimension of the matrix. By convention, the rows are listed first and the columns are listed second.

[0037] Referring to the sensing process 1600 of FIG. 16, a method is also proposed for the receiver STA2 1604 to perform channel measurement adaptation based on an instruction from a transmitter, e.g., transmitter STA1 1602. The transmitter 1602 and the receiver 1604 negotiate their respective opportunistic sensing capabilities. When the transmitter 1602 changes a Tx parameter, it provides a Tx parameter change indication 1608 to the receiver 1604 in the PPDU 1606, where the Tx parameter change indication 1608 indicates the change in the Tx parameter from the previous transmission. Thereafter, when the receiver 1604 receives the Tx parameter change indication 1608 from the transmitter 1602, it can perform a normalized channel measurement on the PPDU 1606 incorporating the Tx parameter change 1608, advantageously compensating for variations in the channel measurement due to, e.g., the change in the Tx parameter.

[0038] In the first embodiment, the receiver STA can perform WLAN sensing based on its capabilities from the PPDU received from the STA with which it wants to perform sensing. For example, referring to the diagram 1700 of FIG. 17, STA2 1702 can perform MAC filtering to filter out PPDUs other than those from the STA with which STA2 1704 wants to perform sensing, and then select the benchmark PPDU. Then, WLAN sensing is performed between STA1 1704 and STA2 1702, and STA2 1702 is an opportunistic sensing-enabled STA.

[0039] 18, the benchmark PPDU (e.g., PPDU 1806 received from transmitter 1802) results in a "benchmark" channel measurement (e.g., CSI matrix), which is then used to perform channel measurements. For example, receiver 1804 calculates the rank of the benchmark measurement (e.g., CSI matrix) and stores it. During channel measurements for WLAN sensing, receiver 1804 calculates the CSI of the received PPDU (e.g., PPDU 1810) if the format of the received PPDU is the same as that of the benchmark PPDU 1806, and compares the rank of the calculated CSI matrix with the rank of the benchmark measurement. Otherwise, if the received PPDU is determined to be different from the benchmark PPDU 1806 (e.g., PPDU 1808), the PPDU 1808 is filtered out and the measurements derived from the PPDU 1808 are discarded.

[0040] FIG. 19 shows an illustration of the operation of the sensing receiver according to the first embodiment. In step 1902, the receiver STA receives a PPDU. In step 1904, it is determined whether the format of the received PPDU is the same as that of the benchmark PPDU. If the formats are different, the process proceeds to step 1906 and does not extract CSI for the received PPDU. Otherwise, the process proceeds from step 1904 to step 1908 and determines whether the information in the PHY header is the same as the information in the PHY header of the benchmark PPDU. If it is determined that they are not the same, the process proceeds to step 1910 and does not extract CSI for the received PPDU. If it is determined that they are the same, the process instead proceeds to step 1912 and extracts CSI for the received PPDU.

[0041] An example of a PHY receiving procedure for receiving sensing measurements (e.g., CSI) according to the first embodiment is shown in diagram 2000 of Figure 20. The MAC 2002 issues a PHY_CSI_EXTRACT.request primitive 2010 to the PHY 2004 only after it receives a PPDU (e.g., A-MPDU 2006) from which to extract CSI (e.g., after PHY-RXEND.indication 2008 is issued by PHY 2004). After receiving the indication from the MAC, the PHY 2004 passes the CSI to the MAC 2002 using a new primitive PHY-CSI.indication(RXVECTOR) 2012.

[0042] For parameters such as the Q matrix, when the rank of the current channel measurement matrix remains the same as in the benchmark measurements, the receiver performs the following: - If the matrix order of the current channel measurement is the same as the order of the benchmark measurement, the CSI is used for WLAN sensing. - If the current channel measurement result is a higher order matrix than the benchmark measurement result, the responder can extract a subset matrix from the current measurement result based on the Tx chain and antenna selection pair (normalized measurement) and compare it with the benchmark measurement result. - If the current channel measurement result is a lower order matrix than the previous measurement result, the CSI is used for WLAN sensing. - If the rank of the current channel measurement matrix differs from the rank of the benchmark measurement, that measurement is discarded.

[0043] The rank of the matrix indicates whether the change is due to channel variation or a change in the Tx parameters. A change in the CSI matrix due to channel variation does not result in a change in rank. For threshold-based measurements, benchmark measurements can be used interchangeably with threshold measurements.

[0044] FIG. 21 shows another illustration of the operation of the sensing receiver according to the first embodiment. In step 2102, the sensing receiver performs a benchmark measurement. This is after the benchmark PPDU is selected and the subsequent PPDU is matched with the benchmark PPDU. In step 2104, it is determined whether the rank of the current measurement is different from the rank of the benchmark measurement. If the rank of the current measurement is different from the rank of the benchmark measurement, it means that there is a change in the Tx parameters. If it is determined that they are different, the process proceeds to step 2106, and the CSI is not forwarded to the upper layer. If not, the process proceeds from step 2104 to step 2108, and the order of the current measurement is compared with the order of the benchmark measurement. If it is determined that the order of the current measurement is the same as or smaller than the order of the benchmark measurement, the process proceeds to step 2110 or step 2114, respectively, and the CSI is used for sensing. On the other hand, if it is determined in step 2108 that the order of the current measurement is higher than the order of the benchmark measurement, the process proceeds to step 2112, and a subset is extracted from the current measurement (normalized channel measurement).

[0045] In another option, referring to diagram 2200 of FIG. 22, instead of MAC 2202 performing CSI extraction for all PPDUs matching the benchmark format, MAC 2202 can set a PPDU filter (for at least some, if not all, parameters) for PHY 2204 using, for example, PHY-CSI-FILTER-SET.request primitive 2206. This advantageously allows PHY 2204 to perform the PPDU filtering itself, and if the PPDU passes the filter, PHY 2204 can autonomously pass the CSI to MAC 2202, possibly within the same RXVECTOR of the PHY-START.indication used to indicate the start of the data portion (e.g., using PHY-RXSTART.indication(RXVECTOR) primitive 2208). However, the key modification of RXVECTOR is the presence of the CHAN_MAT primitive even if PSDU_length is greater than 0.

[0046] In a variation of the first embodiment, another option for the receiver to perform opportunistic sensing is via a transmit beamforming sequence. Referring to the diagram 2300 of FIG. 23, the receiver STA2 2304 can perform opportunistic sensing based on transmit beamforming performed between the receiver STA2 2304 and a STA with which the receiver STA2 2304 wants to perform channel measurements, for example, the transmitter STA1 2302. If the NDPA 2306 is addressed to the STA performing the opportunistic sensing, the STA can store the CSI calculated with the NDP 2308. Furthermore, if the NDPA 2306 is addressed to another STA instead, the CSI can be extracted from the explicit feedback 2310.

[0047] In another variation of the first embodiment, 802.11az (ranging) sequences can also be used for WLAN sensing. In this case, sensing can be performed even if the other STA supports only 11az and not 11bf. If both STAs support 11az and 11bf, ranging and sensing can be performed simultaneously. For example, referring to the diagram 2400 of FIG. 24, trigger-based ranging 2400 or non-trigger-based ranging 2420 can be used for WLAN sensing between a responder STA (RSTA) 2402 and an initiator STA (ISTA) 2404. In this setup, NDPs can be used for sensing (e.g., I2R NDPs 2408 and 2416, R2I ranging NDPs 2412, and R2I NDPs 2418). If both the responder RSTA 2402 and the initiator ISTA 2404 also support WLAN sensing capability, the trigger frame (e.g., TF ranging sounding frame 2406) and the NDPA (e.g., R2I ranging NDPA and NDPA 2414) can be modified to support sensing.

[0048] According to the second embodiment, for WLAN sensing to be accurate and reliable, it is important for the transmitter to indicate the change in Tx parameters so that the receiver knows that the fluctuation in channel measurements is due to the change in Tx parameters and not due to changes in channel conditions. For example, referring to the diagram 2500 of FIG. 25, the PPDU 2510 transmitted after beamforming 2508 may be different from the PPDU 2506 before beamforming due to factors such as the change in Tx parameters, changes in the channel, etc. The transmitter STA1 2502 can indicate the change in Tx parameters to the receiver STA2 2504, but negotiation is required between the receiver 2504 and the transmitter 2502 for the receiver STA2 2504 to understand such an indication.

[0049] 26, STAs that support opportunistic WLAN sensing may indicate such support in a Sensing capabilities field 2602 in a WLAN Sensing Capability element 2600, for example, using a one-bit indication 2604 indicating that opportunistic sensing is supported. Discovery of STAs that support opportunistic WLAN sensing may be performed in one or all of the following ways: - An AP may advertise its opportunistic WLAN sensing capabilities using a WLAN Sensing Capability element in a beacon, a probe response frame, an association response frame, a FILS discovery frame, etc. A non-AP STA may advertise its opportunistic WLAN sensing capability by including a WLAN Sensing Capability element in frames such as a Probe Request frame, an Association Request frame, etc.

[0050] A non-AP STA can determine whether other non-AP STAs in a BSS associated with the same AP support opportunistic WLAN sensing capability via TDLS. For example, referring to FIG. 27, the WLAN sensing capability element 2600 can be conveyed in a TDLS discovery request / response frame (e.g., a TDLS discovery request frame 2700 and a TDLS discovery response frame 2708 transmitted from STA1 2702 to STA2 2706 via an AP 2704) or a TDLS setup request / response frame. After the STA discovers the capability, it sets up a TDLS link. For example, the sensing setup is performed directly between the STAs, and the PPDU transmitted on the direct path is used for opportunistic sensing.

[0051] After an opportunistic WLAN sensing-enabled STA is discovered, the initiator sends a sensing request to another opportunistic WLAN sensing-enabled STA. Negotiation is also useful in setting the period during which WLAN sensing is performed opportunistically. Opportunistic sensing can also be performed between an opportunistic WLAN sensing-enabled AP and its associated opportunistic WLAN sensing-enabled STAs at a scheduled SP. The negotiated parameters can be: - Sensing period: The period during which the PPDU is used for WLAN sensing - Tx parameters: Tx power, bandwidth, PHY format, etc. - Periodicity: Periodic transmission shall be negotiated to meet the required performance. For example, since WiFi traffic is bursty in nature, during a sensing session the transmitter may not have a PPDU to transmit. In such a case, the transmitter transmits PPDUs to the receiver with a negotiated periodicity (e.g., 10 ms) during the sensing session. The PPDUs may or may not carry a payload.

[0052] For example, in WiFi, traffic is observed to be bursty in nature, and if a PPDU has not been transmitted during a period designated for opportunistic WLAN sensing to be performed, the transmitter will transmit an NDP, etc. at a designated transmission rate.

[0053] FIG. 28 shows an illustration of a sensing session 2800 according to the second embodiment. During sensing setup 2806, a setup request 2806 sent from a STA 2802 to an AP 2804 may include requests for various parameters, such as sensing period, Tx parameters, feedback type, measurement ID, and periodicity. During a sensing session, there may be various regular PPDUs 2808 with different Tx parameters (e.g., a PPDU of a control frame or management frame may use different Tx parameters than a PPDU of a data frame). A kind of ID may be used to identify PPDUs with the same Tx parameters, for example, a setup ID is included in the "sensing A-control field" if a PPDU is intended to be used for a sensing session. Furthermore, a sensing measurement PPDU 2810 under setup for opportunistic sensing shall have the same Tx parameters as a previous regular PPDU 2808 in the same session of sensing setup.

[0054] 29 and 30 respectively show diagrams 2900 and 3000 of sensing sessions according to a variation of the second embodiment. In this variation, all frames 2916 transmitted during sensing measurements 2914 may be addressed to another STA, not to the STA 2902. The sensing STA 2902 may use normal PPDUs 2908 addressed to other stations, and for example, referring to FIG. 30, the sensing STAs 3002, 3004, and 3006 may listen for PPDUs for other STAs, such as frames from the AP 3010 addressed to the other STA 3008. In that case, the sensing setup 2906 is performed between the sensing STA 2902 and the AP 2904 for traffic from the AP 2904 to the other STA. The sensing setup may advantageously allow such a configuration to increase the benefits of opportunistic sensing. During sensing setup 2906, the STA 2902 may indicate to the AP 2904 that it may listen for PPDUs transmitted to another STA.

[0055] According to the second embodiment, the transmitter shall indicate to the receiver about the change in transmission parameters (if any) after the beamforming or Tx parameter change using a one-bit indication in the HE Link Adaptation (HLA) A-control field. Figure 31 shows an illustration of an exemplary HLA A-control field 3100 according to the second embodiment. The one-bit indication can be provided via bit B25 3104 of the Control Information field 3102 of the HLA A-control field 3100. Alternatively, a new A-control field, e.g., a "sensing A-control field", can be defined to indicate the parameters to the receiver. Upon receiving the indication of the change in transmission parameters from the transmitter, the receiver can perform channel measurement as shown in the channel measurement process 3200 of Figure 32.

[0056] The channel measurement process 3200 begins at step 3202, where the transmitter indicates a change in Tx parameters to the receiver. In step 3204, the receiver determines how the received PPDU is filtered according to the MAC filtering procedure from the SPS. If the received PPDU is filtered out, the process proceeds to step 3206, where the receiver MAC does not request CSI for the received PPDU. Otherwise, the process instead proceeds to step 3208, where the rank of the current channel measurement is compared to the rank of the benchmark measurement. If it is determined that the compared ranks are the same, the process proceeds to step 3210, where the current channel measurement is used. If it is determined that the compared ranks are different, the process proceeds to step 3212, where the order of the current measurement is compared to the order of the benchmark measurement. If it is determined that the order of the current measurement is the same as the order of the benchmark measurement, the process proceeds to step 3214, where the channel measurement result is discarded. If it is determined that the order of the current measurement is greater than the order of the benchmark measurement, the process proceeds to step 3216, where the subset is extracted from the channel measurement. If it is determined that the order of the current measurement is less than the order of the benchmark measurement, the process proceeds to step 3218, where the current channel measurement is used for sensing.

[0057] If threshold-based WLAN sensing is implemented, the receiver may choose to perform threshold detection when the Tx Parameter Change bit is set to 1 but the rank is different, as follows: - If the matrix order of the current channel measurement is the same as the order of the benchmark measurement, the receiver may discard the measurement result. - If the current channel measurements are of a higher order matrix than the benchmark measurements, a subset of the current channel measurements shall be extracted based on the Tx chain and antenna selection pair used to compare to the threshold. This subset is called the normalized channel measurements and can be compared to the threshold to determine if it exceeds the threshold. If the current channel measurement result is a lower order matrix than the previous measurement result, the current channel measurement result is used for sensing.

[0058] A new management frame, for example, the WLAN sensing Tx parameter indication frame 3300 of FIG. 33, can be defined, which can be transmitted by the transmitter upon change of Tx parameters. The WLAN sensing Tx parameter indication frame 3300 can include a Tx change indication field 3302 to indicate a change (when present) of Tx parameters, a Tx power field 3304 to indicate the Tx power of the channel, and a Q matrix field 3306 to indicate the Q matrix applied by the transmitter. The transmitter can transmit the WLAN sensing Tx parameter indication frame 3300 when adapting Tx parameters based on beamforming or channel conditions, etc. This frame can be transmitted immediately after the transmitter changes the Tx parameters.

[0059] When a parameter change is performed, the transmitting STA can indicate the new parameters using the WLAN sensing Tx parameter indication frame 3300. Still referring to the diagram 3400 of FIG. 34, the transmitter STA1 3402 can inform the receiver STA2 3404 of the actual Tx parameters (Q matrix, Tx power, etc.) 3408 that the transmitter STA1 3402 has changed for transmission. When the receiver STA2 3404 receives the new Tx parameters from the transmitter STA1 3402, it can perform channel measurement for the indicated PPDU 3406, take the inverse of the received Q matrix, and multiply it by the current channel measurement matrix to obtain the channel before the Q matrix change (calculated channel measurement). If the rank of the calculated channel matrix and the rank of the benchmark measurement are different from each other, it passes the channel measurement result to the upper layer or initiator. If a parameter such as Tx power has changed from the previous transmission, the transmitter can indicate the change in Tx power from the previous transmission to the current transmission in the WLAN sensing Tx parameter indication frame. If the change exceeds the optimal sensing power in the subsequent PPDU, do not extract CSI from the received PPDU 3406. The optimal sensing power can be defined as 50% of the total transmit power (e.g., 100 mW at 2.4 GHz). This can be negotiated during sensing setup or may be application specific. If the Tx power is known to the receiver, calculate the difference between the current Tx power and the benchmark Tx power and assume that there is a change in the channel parameters if the element-wise current channel matrix changes.

[0060] According to the third embodiment, for threshold-based sensing, the initiator can calculate multiple thresholds using different PPDU formats and indicate the thresholds to the responder so that the thresholds correspond to the PPDU formats that fit a particular responder. The initiator can calculate different thresholds corresponding to the PPDU formats based on different PPDU formats and indicate it using the "WLAN sensing threshold" element. The WLAN sensing threshold element can be conveyed in a broadcast / unicast frame (implementation dependent). To set a threshold for a group of STAs, a broadcast frame such as a beacon, a probe response frame, etc. can be used. To set a threshold for an individual STA, a new management frame such as a sensing request frame can be used. Referring to the diagram 3500 of FIG. 35, each of the PPDUs 3506 and 3508 transmitted from the initiator STA1 3502 to the responder STA2 3504 is a different PPDU format that can be used for threshold calculation for threshold-based sensing. STA2 3504 can use a threshold value corresponding to a PPDU format compatible with STA2 3504, which in this case is the threshold value corresponding to the PPDU format of PPDU 3506. As a result, PPDUs (e.g., PPDU 3510) having a PPDU format corresponding to PPDU 3506 are filtered based on the threshold value used for sensing.

[0061] 36 shows an illustration of an exemplary threshold-based sensing procedure 3600 using an NDP according to the third embodiment. In order to maintain the same format of the NDP during threshold calculation and threshold measurement, the transmitter STA1 3602 can save the format of the NDP 3606 used for threshold calculation (e.g., the number of LTFs in the NDP, PPDU format such as HT / VHT, etc.) and use the same format to detect whether the threshold is exceeded during actual channel measurement. Thus, the next NDP 3608 having the same format as the NDP 3606 can be advantageously used for threshold calculation.

[0062] According to the fourth embodiment, when the transmitter changes any of the Tx parameters, the transmitter can provide an indication using one reserved bit so that the receiver can perform channel measurements accordingly. The indication is carried in a frame carried by the PPDU after beamforming. If the indication is valid, the PPDU is used as a benchmark PPDU. Figure 37 shows an illustration of an exemplary normal PPDU frame 3700 according to the fourth embodiment. The protocol version "02" 3702 can be used by the transmitter to indicate to the receiver that the normal PPDU 3700 can be used for sensing. The indication can be carried in the MAC header of a data frame, a management frame, etc. For example, the indication can be carried in a frame transmitted immediately after beamforming.

[0063] According to a fifth embodiment, opportunistic sensing / threshold detection can also be performed using periodically transmitted frames, e.g., beacons 3802, as shown in sensing process 3800 of Fig. 38. A condition is that during a sensing session, an AP capable of opportunistic sensing should not change the transmission parameters over which sensing is performed. The AP can announce the intervals during which the Tx parameters remain constant, e.g., the target wait time (TWT) interval for sensing.

[0064] Thus, opportunistic WLAN sensing can be done based on receiver capabilities without involving a transmitter or a Tx parameter change indication from a transmitter. Additionally, opportunistic WLAN sensing can involve receiver MAC filtering rules, PPDU benchmarking to select a specific PPDU format for WLAN sensing, a one-bit indication from the transmitter (wherein the receiver performs channel measurements to advantageously correct the Tx parameter change indicated by the one-bit indication), the transmitter indicating new Tx parameters using a management frame, and / or multiple thresholds calculated for different PPDU formats to advantageously minimize the impact of PPDU format changes in threshold-based sensing.

[0065] FIG. 39 shows a schematic diagram of a receiver 3900 according to various embodiments. The receiver 3900 can be configured to communicate with a transmitter for sensing measurements and can include a threshold module 3902, which can be configured to calculate a threshold for threshold-based sensing. The threshold module 3902 can also calculate normalized channel measurements for WLAN sensing. The receiver 3900 can further include a sensing module 3904, which can be configured to perform opportunistic sensing. The sensing module 3904 can have its own built-in memory that can be used to store PPDU formats and related information for performing channel measurements, so that channel measurements can be performed by the receiver 3900 without instructions from or involvement of the transmitter.

[0066] 40 shows a schematic diagram of a transmitter 4000 according to various embodiments. The transmitter 4000 can be configured to communicate with a receiver for sensing measurements and can include a sensing module 4002 that can be configured to track changes in Tx parameters and provide appropriate instructions to a receiver, e.g., receiver 3900, during a sensing session.

[0067] 41 shows a flow diagram 4100 illustrating a method of communication according to various embodiments. In step 4104, a first PPDU and a second PPDU are received, where the first PPDU indicates a PHY parameter of the first PPDU and the second PPDU indicates a PHY parameter of the second PPDU. In step 4104, based on a comparison of the first PPDU and the second PPDU and the PHY parameters of the first PPDU and the second PPDU, it is determined whether the first PPDU and the second PPDU are used for sensing.

[0068] 42 illustrates a partially boxed schematic diagram of a communication device 4200 that can be implemented for opportunistic WLAN sensing according to the first to fifth embodiments. The communication device 4200 can be implemented as a STA or an AP according to various embodiments.

[0069] The various functions and operations of the communication device 4200 are arranged in layers according to a hierarchical model, where lower layers report to and receive instructions from higher layers according to IEEE specifications. For the sake of brevity, the details of the hierarchical model are not described in this disclosure.

[0070] As shown in FIG. 42, the communication device 4200 may include a circuit 4214, at least one wireless transmitter 4202, at least one wireless receiver 4204, and multiple antennas 4212 (for simplicity, only one antenna is depicted in FIG. 42 for illustrative purposes). The circuit may include at least one controller 4206, which is used to execute the tasks it is designed to perform with the aid of software and hardware, including controlling communications with one or more other devices in a wireless network. The at least one controller 4206 may control at least one transmit signal generator 4208 for generating frames to be transmitted to one or more other STAs or APs via the at least one wireless transmitter 4202, and at least one receive signal processor 4210 for processing frames received from one or more other STAs or APs via the at least one wireless receiver 4204. At least one transmit signal generator 4208 and at least one receive signal processor 4210 may be independent modules of the communication device 4200 that communicate with at least one controller 4206 for the above-mentioned functions. Alternatively, at least one transmit signal generator 4208 and at least one receive signal processor 4210 may be included in at least one controller 4206. Those skilled in the art will understand that the arrangement of these functional modules is flexible and may vary according to actual needs and / or requirements. The data processing device, storage device, and other related control devices may be provided on a suitable circuit board and / or chipset.

[0071] In various embodiments, during operation, the at least one wireless transmitter 4202, the at least one wireless receiver 4204, and the at least one antenna 4212 can be controlled by at least one controller 4206. Additionally, while only one wireless transmitter 4202 is shown, it will be understood that there may be multiple such transmitters.

[0072] In various embodiments, in operation, the at least one wireless receiver 4204 together with the at least one receive signal processor 4210 form a receiver of the communication device 4200. In operation, the receiver of the communication device 4200 provides the functionality necessary for sensing operations. Although only one wireless receiver 4204 is shown, it will be understood that there may be multiple such receivers.

[0073] The communication device 4200, during operation, provides functionality necessary for opportunistic WLAN sensing. For example, the communication device 4200 may be a first communication device. The receiver 4204, during operation, may receive a first PPDU and a second PPDU, where the first PPDU indicates a PHY parameter of the first PPDU and the second PPDU indicates a PHY parameter of the second PPDU. The circuit 4214, during operation, may determine whether the PHY parameter of the first PPDU and the PHY parameter of the second PPDU are used for sensing based on a comparison between the first PPDU and the second PPDU and the PHY parameters of the first PPDU and the second PPDU.

[0074] The receiver 4204 may be further configured to receive the first PPDU in a first time period and the second PPDU in a second time period, the second time period being after the first time period, and the circuit 4214 may be further configured to use the second PPDU for sensing based on a determination that the first PPDU and the second PPDU have the same PPDU format. The receiver 4204 may be further configured to receive the first PPDU in a first time period and the second PPDU in a second time period, the second time period being after the first time period, and the circuit 4214 may be further configured to store PHY parameters of the first PPDU and extract CSI of the second PPDU if the second PPDU has the same PHY parameters as the PHY parameters of the first PPDU. The first PPDU may further indicate transmission parameters of the first PPDU, and the second PPDU may further indicate transmission parameters of the second PPDU, the transmission parameters of the PPDU including at least one of a Q matrix, a received transmit (Tx) power, a received signal strength indicator (RSSI), a number of long training fields (LTFs), and a number of spatial streams.

[0075] The circuit 4214 may be further configured to determine a benchmark PPDU based on a PPDU format or PHY parameters including the number of LTFs, the number of spatial streams, and the RSSI. The first PPDU may be a benchmark PPDU, and the circuit 4214 may be further configured to store information associated with the benchmark PPDU, compare a PPDU format of the second PPDU to the stored information, and determine whether to perform channel measurements based on the comparison. The stored information may include a CSI matrix associated with the benchmark PPDU, the number of spatial streams, the number of transmit antennas, the bandwidth, and the RSSI. The second PPDU may further include a CSI matrix, and the circuit 4214 may be further configured to calculate a rank of the stored CSI matrix from the benchmark PPDU and compare the rank of the CSI matrix of the second PPDU to the calculated rank of the stored CSI matrix. The circuit 4214 may be further configured to forward the CSI matrix of the second PPDU to a higher layer if the comparison indicates that the rank of the stored CSI matrix and the rank of the CSI matrix of the second PPDU are the same.

[0076] The first communication device 4200 may be further configured to perform channel measurements with the second communication device, the channel measurements may be based on PPDUs transmitted from the second communication device to the third communication device. The first communication device may be further configured to perform channel measurements based on periodic transmissions transmitted from the second communication device.

[0077] Further, the communication device 4200 may be a second communication device. In operation, the circuit 4214 may generate a PPDU indicating a change in a transmission parameter. In operation, the transmitter 4202 may transmit the PPDU to the first communication device so that channel measurements can be performed based on the PPDU and the indicated change in the transmission parameter.

[0078] The transmitter 4202 may be further configured to transmit another PPDU indicating the actual transmission parameters to the first communication device, and the channel measurement may be based on the actual transmission parameters and the indicated change in the transmission parameters. The circuit 4214 may be further configured to set the another PPDU as a non-beamforming PPDU. The circuit 4214 may be further configured to store a null data packet (NDP) format during the threshold calculation phase, and the transmitter 4202 may be further configured to transmit an NDP having the same NDP format as the stored NDP format to the first communication device for the sensing session. The PPDU may indicate the change in the transmission parameters in a medium access control (MAC) header of the PPDU.

[0079] The present disclosure can be implemented by software, hardware, or software cooperating with hardware. Each functional block used in the description of each embodiment above 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 as multiple chips individually, or a single chip can be formed to include some or all of the functional blocks. The LSI can include a data input / output unit coupled to it. Depending on the degree of integration, the LSI can also be called an IC, a system LSI, a super LSI, or an ultra LSI. However, the technology for implementing the integrated circuit is not limited to the LSI, and can be implemented by using a dedicated circuit, a general-purpose processor, or a dedicated processor. Furthermore, an FPGA (Field Programmable Gate Array) that can be programmed after the LSI is manufactured, or a reconfigurable processor that can reconfigure the connections and settings of the circuit cells arranged inside the LSI, can also be used. The present disclosure can be implemented as digital processing or analog processing. If a future integrated circuit technology replaces LSI as a result of advances in semiconductor technology or other derivative technologies, the future integrated circuit technology can be used to integrate the functional blocks. Biotechnology can also be applied.

[0080] The present disclosure may be implemented by any type of apparatus, device, or system having communication capabilities, referred to as a communications device.

[0081] A communication device may include a transceiver and a processing / control circuit. The transceiver may include and / or function as a receiver and a transmitter. The transceiver as a transmitter and a receiver may include an RF (radio frequency) module including an amplifier, an RF modulator / demodulator, etc., and one or more antennas.

[0082] Some non-limiting examples of such communications devices include phones (e.g., mobile phones, smartphones), tablets, personal computers (PCs) (e.g., laptops, desktops, notebooks), cameras (e.g., digital still / video cameras), digital players (digital audio / video players), wearable devices (e.g., wearable cameras, smart watches, tracking devices), game consoles, e-book readers, telehealth / telemedicine devices, vehicles that provide communications capabilities (e.g., cars, airplanes, ships), and various combinations of these.

[0083] Communications devices are not limited to being portable or portable, but can also include any type of apparatus, device, or system that is non-portable or stationary, such as smart home devices (e.g., appliances, lights, smart meters, control panels), vending machines, and any other "things" in the network of the "Internet of Things" (IoT).

[0084] Communications may include, for example, exchanging data through cellular systems, wireless LAN systems, satellite systems, and various combinations thereof.

[0085] A communications device may include devices such as a controller or sensors coupled to the communications device to perform the communications functions described in this disclosure. For example, a communications device may include a controller or sensors that generate control or data signals used by the communications device to perform the communications functions of the communications device.

[0086] The communications devices may further include infrastructure facilities, such as base stations, access points, and any other apparatus, devices, or systems that communicate with or control apparatus such as the apparatus in the non-limiting examples above.

[0087] A non-limiting example of a station may be a station included in a first plurality of stations belonging to a multi-link station logical entity (i.e., MLD, etc.), where the stations of the first plurality of stations, as part of the first plurality of stations belonging to the multi-link station logical entity, share a common Medium Access Control (MAC) data service interface to higher layers, where the common MAC data service interface is associated with a common MAC address or traffic identifier (TID).

[0088] Thus, it can be seen that the present embodiment provides a communication device and a communication method that support opportunistic WLAN sensing.

[0089] In the above detailed description of the embodiments of the present invention, exemplary embodiments have been presented, but it should be understood that a vast number of variations exist. Furthermore, it should be understood that the exemplary embodiments are examples and are not intended to limit the scope, applicability, operation, or configuration of the present disclosure in any way. Rather, the above detailed description provides those skilled in the art with a convenient guide for implementing the exemplary embodiments. It should be understood that various changes can be made in the function and organization of the steps and methods of operation described in the exemplary embodiments, and in the modules and structures of the devices described in the exemplary embodiments, without departing from the scope of the subject matter described in the appended claims.

Claims

1. a first communication device, a receiver configured to receive a first PPDU and a second PPDU, the first PPDU indicating PHY parameters of the first PPDU and the second PPDU indicating PHY parameters of the second PPDU; circuitry configured to receive the first PPDU during a first period of time and to receive the second PPDU during a second period of time that is after the first period of time; the circuitry is configured to use the second PPDU for sensing if the first PPDU and the second PPDU have the same PPDU format and the same PHY header; the PHY parameters include at least one of a minimum number of long training fields (LTFs), a bandwidth, and a Tx power; A first communication device.

2. the circuitry is further configured to store the PHY parameters of the first PPDU and extract CSI of the second PPDU if the second PPDU has the same PHY parameters as the first PPDU. The first communication device according to claim 1 .

3. the first PPDU further indicates transmission parameters of the first PPDU, and the second PPDU further indicates transmission parameters of the second PPDU, the transmission parameters of the first and second PPDUs including at least one of a Q matrix, a received transmit (Tx) power, a received signal strength indicator (RSSI), a number of long training fields (LTFs), and a number of spatial streams; The first communication device according to claim 1 .

4. the circuitry is further configured to determine a benchmark PPDU based on a PPDU format or PHY parameters including a number of LTFs, a number of spatial streams, and an RSSI. The first communication device according to claim 1 .

5. the first PPDU is a benchmark PPDU, and the circuitry is further configured to store information associated with the benchmark PPDU, compare a PPDU format of the second PPDU with the stored information, and determine whether to perform channel measurements based on the comparison. The first communication device according to claim 4 .

6. the stored information includes a CSI matrix, a number of spatial streams, a number of transmit antennas, a bandwidth, and an RSSI associated with the benchmark PPDU; The first communication device according to claim 5 .

7. the second PPDU further includes a CSI matrix, and the circuitry is further configured to calculate a rank of the stored CSI matrix from the benchmark PPDU and compare the rank of the CSI matrix of the second PPDU with the calculated rank of the stored CSI matrix. The first communication device according to claim 6 .

8. the circuitry is further configured to, if the comparison indicates that a rank of the stored CSI matrix and a rank of a CSI matrix of the second PPDU are the same, forward the CSI matrix of the second PPDU to an upper layer. The first communication device according to claim 7 .

9. and further configured to perform channel measurements with a second communication device, the channel measurements being based on a PPDU transmitted from the second communication device to a third communication device. The first communication device according to claim 1 .

10. and further configured to perform channel measurements based on periodic transmissions sent from the second communication device. The first communication device according to claim 1 .

11. 1. A communication method comprising: receiving a first PPDU and a second PPDU, the first PPDU indicating PHY parameters of the first PPDU and the second PPDU indicating PHY parameters of the second PPDU; receiving the first PPDU during a first time period; receiving the second PPDU during a second period of time that is after the first period of time; If the first PPDU and the second PPDU have the same PPDU format and the same PHY header, the second PPDU is used for sensing; the PHY parameters include at least one of a minimum number of long training fields (LTFs), a bandwidth, and a Tx power; Communication method.

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