Communication device for reducing WLAN sensing overhead

Abstract

In order to reduce sounding overhead, multiple mechanisms and methods are provided that can minimize the use of sounding for wireless local area network (WLAN) sensing and associated frame exchanges. A communication device includes a transceiver and a circuit. The transceiver receives a signal from a WLAN in operation. The circuit demodulates and decodes the signal in operation, the decoded signal includes a first PPDU and a second PPDU, and the circuit performs a full channel measurement based on a first PHY header of the first PPDU and a second PHY header of the second PPDU in operation, the first PHY header and the second PHY header include an LTF for estimating channel quality.

Description

Technical Field

[0001] This disclosure generally relates to wireless local area network (WLAN) communication, and more particularly to communication devices for reducing the overhead of WLAN sensing. Place Related thereto.

Background Art

[0002] In modern society, communication devices are widespread in the form of telephones, tablets, computers, cameras, digital audio / video players, wearable devices, game consoles, telehealth / telemedicine devices, vehicles with communication capabilities, and various combinations of the above. Communication includes, for example, data communication through wireless local area network (WLAN) systems, cellular systems, satellite systems, and various combinations thereof.

[0003] WLAN sensing applications typically perform channel measurements, track one or more wireless links over time, and classify channel variations into events / activities. Channel State Information (CSI) provides information on how wireless signals propagate within a channel with various effects such as time delay, amplitude attenuation, and phase shift on each subcarrier, so CSI measurements may be utilized for WLAN sensing.

[0004] In WLAN communication, CSI is calculated based on the LTF (long training field) of the PHY (physical layer) header. The difference between the transmitted LTF and the received LTF is the channel state information. The receiver estimates the CSI matrix using a predefined signal and the received signal after performing reception processing such as removal of the cyclic prefix, demapping, and OFDM demodulation.

[0005] According to current WLAN specifications, channel measurement is performed using NDP (null data packet) LTF. Consider a scenario where sensing needs to be performed 10 times per beacon interval. Sounding can take up to approximately 1 millisecond during the beacon interval. Depending on the WLAN sensing application, very frequent channel measurements may be required, significantly increasing the number of soundings. Based on WLAN sensing use cases, a sensing overhead of up to 10 percent is expected in many scenarios. In a single initiator and single responder scenario, if channel measurements are performed more than 10 times per beacon interval, the sensing overhead could exceed 10 percent. With multiple initiators and multiple responders, the network overhead for sensing can increase significantly.

[0006] Therefore, in order to reduce the overhead of sounding, there is a need for communication devices and communication methods for reducing the overhead of WLAN sensing to mitigate the aforementioned problems by minimizing the use of sounding for WLAN sensing and the associated frame exchange. Furthermore, other desirable features and characteristics will become apparent from the following detailed description and the attached claims, in conjunction with the attached drawings and their background. [Overview of the project]

[0007] Non-limiting and exemplary embodiments of this disclosure contribute to providing several mechanisms and methods that can minimize the use of sounding for wireless local area network (WLAN) sensing and associated frame exchange in order to reduce sounding overhead.

[0008] In one embodiment, the technology disclosed herein is characterized by a communication device having a transceiver and a circuit. The transceiver receives a signal from a WLAN when in operation. The circuit demodulates and decodes the signal when in operation, the decoded signal includes a first PPDU (physical layer protocol data unit) and a second PPDU, the circuit performs a full channel measurement when in operation based on a first PHY (physical layer) header of the first PPDU and a second PHY header of the second PPDU, the first PHY header and the second PHY header include a long training field (LTF) for estimating channel quality.

[0009] These comprehensive or specific embodiments may be implemented as a system, method, integrated circuit, computer program, or recording medium, or as any combination of a system, device, method, integrated circuit, computer program, and recording medium.

[0010] Further advantages and effects of one embodiment of this disclosure will be made apparent from the specification and drawings. Such advantages and / or effects are provided by several embodiments and features described in the specification and drawings, but not all of them are necessarily provided in order to obtain one or more identical features. [Brief explanation of the drawing]

[0011] In the following, exemplary embodiments will be described in more detail with reference to the attached drawings. [Figure 1] This diagram shows an example of a wireless local area network (WLAN) system and the communication equipment in operation. [Figure 2] Figures 2A and 2B show block diagrams of an example of a communication device. Figure 2A shows an example of a wireless station (STA) communication device, and Figure 2B shows a wireless access point (AP). [Figure 3]This diagram shows an example of conventional WLAN sensing during communication between an access point (AP) and a wireless station (STA) in a WLAN system. [Figure 4] This figure shows a conventional threshold-based feedback mechanism for WLAN sensing. [Figure 5] This figure shows the three phases of the WLAN sensing method related to this disclosure. [Figure 6] This figure shows the communication between the initiator and responder for threshold calculation related to this disclosure. [Figure 7] This figure shows the WLAN sensing threshold elements related to this disclosure. [Figure 8] This figure shows the channel measurement scenario related to this disclosure. [Figure 9] This figure shows a block Ack frame that notifies of a threshold exceedance, as per the disclosure. [Figure 10A] This figure shows the sensing procedure according to this disclosure when multiple responders simultaneously exceed a threshold. [Figure 10B] This figure shows the NDPA frame used in the sensing procedure according to this disclosure when multiple responders simultaneously exceed a threshold. [Figure 11] This figure shows the sensing request frame related to this disclosure. [Figure 12] This diagram shows the sensing procedure when the feedback type field is set to NDP (null data packet) according to this disclosure. [Figure 13] This diagram shows the sensing procedure when the feedback type field is set to "partial feedback" according to this disclosure. [Figure 14] This diagram shows the sensing procedure when the feedback type is set to "explicit feedback" according to this disclosure. [Figure 15] This figure shows the communication between an initiator and multiple responders for threshold calculation related to a modified version of the present disclosure. [Figure 16]Composed of FIGS. 16A and 16B, it shows the threshold setting according to the present disclosure. FIG. 16A is an illustration of the threshold setting, and FIG. 16B is a diagram showing the threshold management frame according to the present disclosure. [Figure 17] It is a diagram showing channel measurement according to the present disclosure, in which the responder notifies the initiator of exceeding the threshold by sending a sensing request frame. [Figure 18] It is a diagram showing the sensing procedure performed according to the sensing request frame according to the present disclosure. [Figure 19] It is a diagram showing the sensing procedure performed according to the sensing request frame sent by the responder according to the present disclosure. [Figure 20] It is a diagram showing the sensing procedure according to the present disclosure, in which the responder notifies exceeding the threshold and directly sends an NDPA frame. [Figure 21] It is a diagram showing the sensing procedure according to the present disclosure, in which the responder directly sends an NDPA frame without first notifying exceeding the threshold. [Figure 22] It is a diagram showing the first cooperative sensing procedure according to the present disclosure, in which the sensing initiator is neither a sensing transmitter nor a sensing receiver. [Figure 23] It is a diagram showing the second cooperative sensing procedure according to the present disclosure, in which the sensing initiator is neither a sensing transmitter nor a sensing receiver. [Figure 24] Composed of FIGS. 24A and 24B, it is a diagram of the frame used in the cooperative sensing procedures of FIGS. 22 and 23 according to the present disclosure. FIG. 24A shows the sensing control frame, and FIG. 24B shows the NDPA frame. [Figure 25] It is a diagram showing the sensing procedure according to the present disclosure, in which a guard PPDU is used to request feedback. [Figure 26] It is a diagram showing the sensing procedure according to the present disclosure, in which an EHT (extra high throughput) PPDU is used to request feedback. [Figure 27]Figures 27A and 27B are diagrams of the PPDU used in the sensing procedure of Figure 26 relating to this disclosure. Figure 27A shows the EHT (extra high throughput) PPDU, and Figure 27B shows the HT (high throughput) PPDU. [Figure 28] This figure shows a beamforming procedure using the sensing procedure described herein. [Figure 29] Conventional WLAN sensing is shown in a diagram. [Figure 30] This diagram shows the WLAN sensing related to this disclosure. [Figure 31] This is a block diagram of the WLAN sensing device related to this disclosure. [Figure 32] This is a block diagram showing the form of a single-device implementation of the WLAN sensing system related to this disclosure. [Figure 33] This is a block diagram showing the configuration of a centralized multiple-device implementation of a WLAN sensing system related to this disclosure.

[0012] Those skilled in the art will understand that the elements in the figure are shown in a simple and clear manner and are not necessarily drawn to a fixed scale. [Modes for carrying out the invention]

[0013] The following detailed description is essentially illustrative and is not intended to limit the exemplary embodiments or the application and use of exemplary embodiments. Furthermore, it is not intended to be constrained by the aforementioned background or any theory presented in the following detailed description. This disclosure is intended to present exemplary embodiments of communication devices and communication methods for reducing WLAN overhead by minimizing the use of sounding for WLAN sensing and associated frame exchange in order to reduce sounding overhead.

[0014] Figure 1 is a diagram 100 showing an example of a WLAN system within office 102. Access points (APs) 110a, 110b, 110c, 110d, 110e, and 110f each have corresponding service areas (BSS: Basic Service Set) 115a, 115b, 115c, 115d, 115e, and 115f, respectively. In densely populated WLAN environments such as within office 102, the locations of APs 110a, 110b, 110c, 110d, 110e, and 110f are defined so that their service areas 115a, 115b, 115c, 115d, 115e, and 115f overlap, as shown in diagram 100, for better service coverage. Within service areas 115a, 115b, 115c, 115d, 115e, and 115f, wireless stations (STAs) 120a, 120b, 120c, 120d, 120e, and 120f communicate with access points (APs) 110a, 110b, 110c, 110d, 110e, and 110f. APs 110a, 110b, 110c, 110d, 110e, and 110f communicate with server 130 to provide STAs 120a, 120b, 120c, 120d, 120e, and 120f with the Internet, intranet, and other resources. Person 135 within service area 115d may affect the channel between STA 120d and AP 110d, as described below. A second office 160 has an AP that communicates internally with STA 150.

[0015] A wireless station (STA) 120 is a communication device that operates on a WLAN system. Figure 2A is a block diagram 200 of an exemplary STA 120. The STA 120 may include devices such as a control unit 202 coupled to a communication device connected to an antenna 206, such as a transceiver 204 that performs communication functions as described in this disclosure. For example, the STA 120 may include a control unit 202 that generates control signals and / or data signals used by the transceiver 204 to perform the communication functions of the STA 120. The STA 120 may also include a memory 208 coupled to the control unit 202 for storing instructions and / or data for the generation of control signals and / or data signals by the control unit 202. The STA 120 may also include an input / output (I / O) circuit 210 coupled to the control unit 202 for receiving input of data and / or instructions to be stored in the memory 208, and / or for generating control signals and / or data signals, and for providing data output in the form of audio, video, text or other media.

[0016] STA120 communicates with access point (AP) 110 within the WLAN system 100 and accesses resource units (RUs) via server 130 to exchange data with the Internet, other communication devices, or other systems. Figure 2B is a block diagram 250 of an exemplary AP110. AP110 includes infrastructure equipment that communicates with or controls STA120a, 120b, 120c, 120d, 120e, 120f, or other communication devices as shown in Figure 2A. AP110 may include devices such as a control unit 252 coupled to a communication device connected to an antenna 256, such as a transceiver 254 that performs communication functions as described in this disclosure. For example, AP110 may include a control unit 252 that generates control signals and / or data signals used by the transceiver 254 to perform the communication functions of AP110 with STA120. AP110 may also include a memory 258 coupled to the control unit 252 for storing instructions and / or data for generating control signals and / or data signals by the control unit 252. AP110 may also include an input / output (I / O) circuit 260 coupled to the controller 252 for receiving input data and / or instructions for storage in the memory 258, and / or for generating control signals and / or data signals to enable communication between STA120 and the RUs, for example, for coupling with various RUs provided by the server 130.

[0017] Conventional WLAN sensing applications perform channel measurements, tracking one or more radio links over time and classifying channel variations into events / activities. Channel Status Information (CSI) is used as a channel measurement parameter in WLAN sensing because it provides information describing how radio signals propagate within a channel, with various effects such as time delay, amplitude attenuation, and phase shift on each subcarrier. The difference between the transmitted Long Training Field (LTF) and the received Long Training Field (LTF) lies in the CSI. After receiving processing such as cyclic prefix removal, demapping, and OFDM demodulation, the receiver estimates the CSI matrix "H" using a predefined signal "x" and the received signal "y". The estimated CSI is a complex-valued three-dimensional matrix H.

[0018] Figure 3 is an illustration 300 of a conventional WLAN sensing example during communication between AP310 and STA320 in a WLAN system. After normal communication 330, WLAN sensing 335 is performed. According to the current specification, channel measurement is performed using LTF from NDP (null data packet) 340. In illustration 300, AP310 is assumed to be the sensing initiator and STA320 is assumed to be the sensing responder. Table 1 shows the sensing airtime when sensing is performed at beacon intervals. [Table 1]

[0019] As shown in Table 1, sounding can take up to approximately 1 millisecond (ms) during a beacon interval. Depending on the WLAN sensing application, very frequent channel measurements may be required, significantly increasing the number of soundings. Conventional WLAN sensing is expected to have a sensing overhead of up to 10% in a single initiator and single responder scenario. In an exemplary wireless local area network system 102 (Figure 1) with multiple initiators and responders, the network overhead for WLAN sensing can increase significantly. The WLAN sensing according to this disclosure minimizes the use of sounding and associated frame exchange for WLAN sensing in order to reduce sounding overhead.

[0020] Figure 4 illustrates a conventional threshold-based feedback mechanism for WLAN sensing.400 The initiator STA (ISTA) sets a threshold for each responding STA by transmitting a sensing NDP405 and periodically transmits an NDP410 to all RSTAs after SIFS (short interframe space). In response to a TF (Trigger Frame) sensing polling415, the responding STA (RSTA1) sends a "CTS (clear to send)"420 to the ISTA. In response to a TF sensing sounding425, the RSTA1 measures the CSI and compares it to the previous measurement result. If the difference in CSI exceeds the threshold, the RSTA1 sends an NDP430 to the ISTA (scheduling may be required). Otherwise, the RSTA1 stores the measurement result and provides no feedback. The ISTA can perform its own sensing measurement based on the NDP430 transmitted by the responding STA. In this conventional WLAN sensing method, NDP sounding is performed to measure the channel to determine if a threshold has been exceeded, but this can be detrimental as it adds overhead to normal communication and results in additional frame exchange.

[0021] Figure 5 illustrates a channel sounding method for reducing overhead and network load according to this disclosure. The channel sounding method according to this disclosure includes three phases 510, 520, and 530. The STA performs channel estimation based on normal PPDU (Physical Layer Protocol Data Unit) received from other STAs and checks whether a threshold has been exceeded. If the threshold has been exceeded, a full channel measurement is performed. In other words, the first phase of the WLAN sensing method according to this disclosure is the threshold setting phase 510. During the threshold setting phase 510, the STA learns the threshold above which a full channel measurement should be performed. During the second normal communication phase 520, the STA performs a channel measurement to extract the CSI and compares the extracted CSI value with a reference CSI value to determine whether a threshold has been exceeded based on the difference in the CSI value. CSI is a channel measurement parameter that measures channel quality. According to this disclosure, other channel measurement parameters, such as time reversal resonating strength (TRRS), signal-to-noise ratio (SNR), or detected channel energy, can be extracted during the execution of channel measurements.

[0022] During sensing processing phase 530, the STA performs a full channel measurement if a threshold is exceeded. A standard PPDU may be used for the channel measurement. In accordance with this disclosure, the sounding overhead is significantly reduced by using a standard PPDU to determine whether a threshold has been exceeded for channel measurement.

[0023] A typical PPDU-based channel measurement is performed only on LTFs present in the PPDU, which may be less than or equal to the number of spatial streams (SS) supported by the transceivers 204, 254, and may or may not estimate the complete channel. According to this disclosure, a full channel measurement may use an NDP (any number of LTFs) or a staggered PPDU (a PPDU containing additional LTFs) for sounding the complete channel.

[0024] Referring to Figure 6, Illustration 600 of the communication between initiator and responder illustrates the threshold calculation relating to this disclosure. Both initiator 610 and responder 620 may be either AP110 or STA120. In Illustration 600, initiator 610 is an AP, and responder 620 is one of the STAs associated with the AP.

[0025] A threshold is calculated before WLAN sensing is performed (630), and WLAN sensing is performed during the offline training phase in accordance with this disclosure. The offline training phase is the time before actual sensing is performed, during which the AP prepares the associated STA and a database of channel impulse responses. When the AP, which is the initiator 610, receives an uplink frame 640 from the responder 620, the initiator 610 calculates the channel impulse response. This step may be repeated at various time instances and locations to prepare a database of channel impulse responses (CIRs) to have knowledge of localized objects in the environment within the AP's associated service area 115. Once the database is prepared, when the AP receives another uplink frame 650, it calculates a time-reversed CIR and convolves it with the CIRs in the database. This is a threshold for the target responder 620, which is set (660) by the transmission (670) of a beacon frame or unicast management frame containing the calculated threshold from the initiator 610 to the responder 620, resulting in the maximum focusing gain for the responder 620.

[0026] According to this disclosure, two methods are possible for calculating the threshold 630. The first method is time-reversed resonance intensity (TRRS) calculation, and the second method is the cross-correlation method. According to the TRRS method, the CIR can be calculated as shown in equations (1) and (2).

number

number

[0027] h1 and h2 are channel impulse responses (CIRs). CIRh2 is time-reversed and convolved with CIRh1. In equation (3), the threshold is calculated as the maximum value of h2 that has been time-reversed and convolved with various values ​​from the database, which is set as the threshold.

number

[0028] Equation (3) reveals that the TR resonance strength is the maximum amplitude of the entry into the cross-correlation between the two complex CIRs. The main reason for using the TR resonance strength instead of the conventional correlation coefficient is to increase robustness against channel estimation errors.

[0029] The threshold can also be calculated using the cross-correlation method, simply by using the correlation coefficient between the two channel impulse responses h1 and h2. To calculate the threshold, it is assumed that the initiator already has a CIR database and understands the responder's position. The threshold is defined as the maximum value of the cross-correlation between the two channel impulse responses.

[0030] As an initiator 610, the AP can set thresholds for all associated STAs participating in WLAN sensing by sending a beacon frame or unicast management frame (670). After the initiator 610 calculates the thresholds for the responders 620 (630), the initiator 610 may set the thresholds according to the threshold setting phase 510 (Figure 5) using the WLAN sensing elements defined in accordance with this disclosure. Referring to Figure 7, Figure 700 shows a WLAN sensing element 710 used to notify the responders 620 of the thresholds. The WLAN sensing element 710 includes a sensing threshold field 720 containing the threshold as a value between 0 and 100 in increments of 10, and a sensing threshold timeout field 730. The sensing threshold timeout field 730 indicates the time during which a full channel measurement may be performed, i.e., if none of the responders 620 (e.g. STAs) with a set threshold exceed the threshold during the “sensing threshold timeout”, the STAs that have timed out may perform a full channel measurement. The WLAN sensing element 710 may be carried in a beacon frame as described above, or in other broadcast frames such as a probe response frame or a unicast management frame.

[0031] Any PPDU in communication received by the responding STA can be used for channel measurement. The important point is the availability of the PHY header for estimating channel quality using the LTF present in the PHY header. Referring to Figure 8, Figure 800 shows a first channel measurement scenario involving three STAs, where STA1 810 is the sensing initiator radio station, and STA2 820 and STA3 830 are the sensing responder radio stations. STA2 820 and STA3 830 perform channel measurement based on the LTF from normal PPDUs 840 and 850 received from STA1 810. STA2 820 and STA3 830 calculate the CSI value (845) and store the CSI value. STA2 820 and STA3 830 then calculate the CSI difference between the later calculated CSI value and the stored CSI value from the previous measurement (855). If the CSI difference exceeds the threshold, the responder STA (STA3 830) that has exceeded the threshold may notify the initiator STA (STA1 810) that the threshold has been exceeded using an uplink frame 860 in OFDMA communication, such as a block Ack (BA) frame or a unicast action frame. The initiator STA (STA1 810) then sends a sensing request 870 to the responder STA that has exceeded the threshold (i.e., STA3 830).

[0032] WLAN sensing applications such as fall detection and motion detection can benefit from the CSI difference calculation (855) when it is calculated between the current CSI value and the previous CSI value. This is because the calculation can provide an instantaneous change in the CSI value that triggers the initiator (STA1 810) to begin full-channel measurement when a threshold is exceeded.

[0033] Referring to Figure 9, Figure 900 shows a block ack frame 910 of block ack 860 according to the present disclosure. The block ack frame 910 includes a block ack request (BAR) control field (BAR control) 920. When responder 830 exceeds a threshold, a threshold exceed bit is set in the block ack frame 910 according to the present disclosure. One threshold exceed bit 930 may be used to indicate the threshold exceeded from a spare bit 940 in the BAR field 920 of the block ack frame 910.

[0034] Returning to Figure 800 (Figure 8), when a sensing responder (e.g., STA3 830) notifies of a threshold exceedance, the initiator (STA1 810) may send a sensing request action frame to the responder to trigger a full channel measurement. In the sensing sequence shown in Figure 800, STA1 810 (initiator) sends a sensing request frame 870 to STA3 830 (responder) that notified of a threshold exceedance. If multiple responders exceed the threshold, the initiator may send WLAN sensing request frames to the responders that have exceeded the sensing threshold.

[0035] Referring to Figure 10A, Figure 1000 shows a sensing procedure according to this disclosure when multiple responders simultaneously exceed a threshold. Multiple responders STA2 820 and STA3 830 simultaneously exceed the threshold. Initiator STA1 810 sequentially transmits sensing requests 1010 and 1020 to the STA. The responder STAs (STA2 820 and STA3 830) according to this disclosure are sensing transmitters and sequentially transmit NDP frames 1018 and 1028 to the initiator STA (STA1 810) in order to perform channel measurements. Before transmitting NDP frames 1018 and 1028, the responder STAs (STA2 820 and STA3 830) transmit NDPA frames 1015 and 1025 to notify the initiator of "no feedback" so that the initiator does not have to send explicit feedback.

[0036] Figure 10B shows an NDPA frame 1050, such as NDPA frame 1015 or NDPA frame 1025, relating to this disclosure. The STA information field 1060 includes a feedback type subfield 1070 which contains information 1080 indicating “No feedback”.

[0037] Referring to Figure 11, Figure 1100 shows a sensing request frame 1110 according to this disclosure. The sensing request frame 1110 includes a MAC header 1120 and a frame body 1130. The sensing request frame 1110 is defined as a management action frame, and according to this disclosure, the frame body 1130 includes a category field 1132, an action field 1134, a responder / initiator flag field 1136, a threshold overflow field 1138, and a feedback type field 1140. The category field 1132 is SENS, and the action field 1134 is a WLAN sensing request. The responder / initiator flag (Resp / Ini flag) field 1136 indicates whether the STA that sent the frame is a responder or an initiator. The threshold overflow field 1138 indicates that the STA that sent the sensing request frame 1110 has exceeded a threshold. The feedback type field 1140 determines the type of feedback during the sensing session. The feedback type field 1140 is allocated one octet, of which two bits are used to indicate the feedback type, and the other bits are reserved for future use. Table 2 shows the types of feedback relating to this disclosure. [Table 2]

[0038] Figure 12 illustrates the sensing procedure according to this disclosure when the feedback type field 1140 in the sensing request frame 1110 is set to NDP (null data packet). When the initiator (STA1 810) receives a threshold exceedance notification in block Ack 1205, it sends a sensing request 1210, in which the feedback type field 1140 in the sensing request frame 1110 is set to NDP, to the responder (STA3 830) that has exceeded the sensing threshold. In this case, when the initiator STA1 810 receives the NDP 1220 from the responder STA3 830, it performs a channel measurement.

[0039] Figure 13 illustrates the sensing procedure according to this disclosure when the feedback type field 1140 in the sensing request frame 1110 is set to "partial feedback". When the initiator (STA1 810) receives a threshold exceedance notification in block Ack 1305, it sends a sensing request 1310 in which the feedback type field 1140 in the sensing request frame 1110 is set to "partial feedback" to the responder (STA3 830) that has exceeded the sensing threshold. After Ack (1320) the sensing request 1310, the responder STA3 830 sends partial feedback 1330, which is part of the stream information corresponding to the number of spatial streams (SS) in the data section, to the initiator STA1 810 based on the received quality information of the LTF contained in the non-NDP PPDU 1350. The initiator STA, such as STA1 810, may request partial feedback depending on the sensing application. For example, in cases such as object location or presence detection, partial feedback can be useful by taking advantage of the fact that if the CSI of the SS related to the data changes, some change may occur in the environment.

[0040] Figure 14 illustrates the sensing procedure according to this disclosure when the feedback type field 1140 in the sensing request frame 1110 is set to "explicit feedback". When the initiator (STA1 810) receives a threshold exceedance notification in block Ack 1405, it sends a sensing request 1410 in which the feedback type field 1140 in the sensing request frame 1110 is set to "explicit feedback" to the responder (STA3 830) that has exceeded the sensing threshold. When initiator STA1 810 requests explicit feedback from responder STA3 830, and responder STA3 830 Ack(1420), initiator STA1 810 sends an NDP frame 1430 to responder STA3 830 notifying that responder STA3 830 has performed a full channel measurement and will provide explicit channel measurement feedback 1440 to initiator STA1 810. This scenario is useful when the responding STA is a computing-intensive device such as a smart TV or laptop computer.

[0041] The initiator may also request channel measurement feedback 1440 from the responder based on the type of application. For applications requiring full channel measurement, the responder may send an NDP to the initiator, and the initiator may perform the full channel measurement itself. The initiator may also request partial feedback 1330, usually based on LTF from PPDU 1350. This may not be a complete channel measurement, but it can significantly reduce the network load for certain applications such as automated lighting. The initiator may request explicit feedback 1440 from the responder if the threshold is exceeded. In this case, the initiator can send an NDP 1430 to the responder so that a full channel measurement is performed and explicit feedback 1440 is sent back. The initiator may also choose not to perform the measurement when the threshold is exceeded, in which case the responder may save the results and continue normal communication.

[0042] Referring to Figure 15, Figure 1500 shows communication between an initiator STA1 1510 and several responders STA2 1520 and STA3 1530 for threshold calculation 1540 according to a modified example of the present disclosure. In Figure 1500, the threshold calculation initiator is STA1 1510. The threshold calculation initiator STA1 1510 may send NDPs 1550, 1560, 1570, and 1580 to responders STA2 1520 and STA3 1530 for initiator STA1 1510 to estimate the complete channel. This process may be repeated several times, as shown in Figure 1500. Responders STA2 1520 and STA3 1530 calculate the CSI and send explicit feedbacks 1555, 1565, 1575, and 1585 containing the calculated CSI. The initiator STA1 1510 may select an appropriate CSI as the reference CSI. The selection of the CSI value can be based on the application. For example, highly sensitive applications that require rapid measurement, such as fall detection or motion detection, may have a lower reference CSI value, such as the minimum CSI received over time from the responders STA2 1520 and STA3 1530. Applications that do not require frequent measurement, such as presence detection or intruder detection, may have a relatively high reference CSI value, such as the maximum CSI received over time from the responders STA2 1520 and STA3 1530. The initiator STA1 1510 determines whether a threshold is exceeded based on the difference between the current CSI measurement and the CSI calculated based on the reference CSI.

[0043] Returning to Figure 8, when a sensing responder (e.g., STA3 830) notifies the initiator STA1 810 of a threshold exceedance in block Ack 860, the initiator sends a sensing request action frame 870 to the responder STA3 830 that notified of the threshold exceedance. For example, suppose AP 110 sets the threshold to 70%. A subset of reference CSIs with SS in the data PPDU is used to calculate the difference between the previous CSI 845 and the next CSI 855. Furthermore, consider the case where the difference is 69% and after 10 iterations the difference decreases to 60%. As long as the threshold of 70% is not exceeded, the value of the CSI difference continues to decrease. In such a case, the threshold may interfere with sensing. To address this problem, according to this disclosure, a reference threshold can be set by the AP / initiator to determine the CSI difference (scheduling may be required). If the CSI difference between the reset threshold and the current CSI value exceeds the threshold, the response STA can notify the AP that the threshold has been exceeded.

[0044] Referring to Figure 16A, Figure 1600 shows a threshold setting according to a modified example of the present disclosure. The initiator STA1 1610 uses a threshold setting management frame 1660 to notify each responder (STA2 1620 and STA3 1630) of their thresholds. That is, the initiator STA1 1610 sends a first threshold setting 1640 to responder STA2 1620 and a second threshold setting 1645 to responder STA3 1630. In this way, each responder can have different thresholds that better control the responder's thresholds, and as a result can provide better sensing capabilities.

[0045] Figure 16B is Figure 1650 of the threshold setting management frame 1660 according to the present disclosure. The threshold management frame 1660 includes a MAC header 1662 and a frame body 1664. The frame body 1664 includes a threshold setting field 1670 indicating that frame 1660 is a threshold setting management frame. The frame body 1664 also includes a reference CSI field 1675 and a sensing threshold timeout field 1680. The reference CSI field is variable and may have a VHT (Very High Throughput) compressed feedback format or a CSI matrix feedback format. The sensing threshold timeout field 1680 includes information indicating the time after which an initiator can perform a full channel measurement.

[0046] Figure 17 is an illustration of channel measurement 1700 in which initiator STA1 1710 communicates with responders STA2 1720 and STA3 1730, and responder STA3 1730 notifies of a threshold exceedance in accordance with this disclosure by sending a sensing request frame 1740 to initiator STA1 1710. The sensing request frame 1740 may be sent by an STA when a threshold is exceeded, if the STA sending the sensing request frame is the initiator itself or a responder.

[0047] Figure 18 illustrates the sensing procedure performed in response to a sensing request frame 1740 according to this disclosure. When an STA exceeds a threshold, it sends a sensing request frame to another STA and requests an NDP 1810 to perform a full-channel measurement. If the STA that exceeds the threshold (STA3 1730) is the initiator, the initiator STA may request the necessary type of feedback (e.g., an NDP 1220, partial feedback 1330, or explicit feedback 1440) as described above. If the STA that exceeds the threshold (STA3 1730) is the responder, it may notify the initiator (STA1 1710) of the threshold exceedance and return a report of the measurement results to the initiator.

[0048] Figure 19 illustrates the sensing procedure 1900 performed in response to a sensing request frame 1740 transmitted by a responder (STA3 1730) to an initiator (STA1 1710) according to the present disclosure. In this case, if the threshold is exceeded, STA3 1730 requests a channel and an NDP 1810 from the initiator, and may, for example, return a report of the full channel measurement result to the initiator STA1 1710 in explicit feedback 1910.

[0049] Figure 20 illustrates a sensing procedure in accordance with this disclosure, in which a responder (STA3 1730) notifies an initiator (STA1 1710) of a threshold exceedance in block Ack frame 2010 and directly transmits NDPA frame 2020 and NDP frame 2030. Since initiator STA1 1710 is a Transmit Opportunity Period (TXOP) holder, it may transmit other PPDUs that could cause a collision with the sensing measurement frames transmitted from STA3 1730. To mitigate this situation, STA3 1730 may perform channel contention and directly transmit a sounding sequence to perform a full channel measurement. In this scenario, NDPA frame 1055 (Figure 10B) may notify "No Feedback" 1080 so that STA1 1710, upon receiving this notification, does not need to send feedback after performing the channel measurement. The sensing procedure shown in Figure 2000 is fast, but requires channel contention by the STA3 1730 as a sensing transmitter.

[0050] Figure 21 illustrates a sensing procedure in accordance with this disclosure in which a responder (STA3 2130) directly transmits an NDPA frame 2140 when the threshold is exceeded, without first notifying that the threshold has been exceeded. The responder STA3 2130 may perform channel contention to directly transmit a sounding frame to the initiator STA1 2110 when the threshold is exceeded without any notification. STA1 2110 can then perform channel measurement and use the measurement results for the sensing application.

[0051] Referring to Figure 22, Figure 2200 shows a first cooperative sensing procedure relating to this disclosure in which the sensing initiator (STA1 2210) is neither a sensing transmitter nor a sensing receiver. STA2 2220 is the sensing transmitter, and STA3 2230 is the sensing responder and sensing receiver. STA2 2220 and STA3 2230 perform WLAN sensing, and STA3 2230 performs channel measurements based on PPDUs 2240 and 2245 from STA2 2220. When a threshold is exceeded, STA3 2230 notifies STA2 2220 of this with a block Ack frame 2250. Upon receiving the block Ack frame 2250, STA2 2220 sends a sensing control frame 2260 to STA1 2210 to notify STA1 2210 of the start of the sensing procedure performed by STA3 2230. Then, STA1 2210 sends NDPA frame 2265 and NDP frame 2270 to STA3 2230, STA3 2230 performs a full channel measurement and returns the result to STA2 2220, STA2 2220 sends the result as explicit feedback 2280 to the initiator (STA1 2210). STAs not participating in normal communication may perform WLAN sensing, and this cooperative sensing procedure is useful in centralized systems where a central entity manages sensing applications.

[0052] Figure 23 illustrates a second cooperative sensing procedure according to this disclosure, in which the sensing initiator STA1 2210 is neither a sensing transmitter nor a sensing receiver. This cooperative sensing procedure operates similarly to the cooperative sensing procedure in Figure 2200 until STA2 2220 transmits a sensing control frame 2260 to STA1 2210. Subsequently, STA1 2210 transmits a "sensing start" frame 2310 to STA2 2220, requesting STA2 2220 to perform a full-channel measurement. STA2 2220 then transmits an NDPA frame 2315 and an NDP frame 2320 to STA3 2230. STA3 2230 performs the full-channel measurement and returns the results to STA2 2220, which then transmits the results as explicit feedback 2280 to the initiator (STA1 2210).

[0053] Figure 24A shows Figure 2400 of the sensing control frame 2260 transmitted to the initiator STA1 2210 when the STA exceeds a threshold, as per the present disclosure. The sensing control field 2410 and the threshold exceeding field 2420 of the frame body 2405 notify the initiator STA1 2210 that a sensing procedure is about to begin. The association ID (AID) 2430 indicates the STA that is about to perform the sensing procedure.

[0054] Figure 24B shows Figure 2450 of NDPA frames 2265 and 2315 relating to this disclosure. As an alternative to the two-part transmission of explicit feedback as shown in Figures 2200 (Figure 22) and 2300 (Figure 23) and described above, the NDPA frame may notify the address 2460 of the initiator to which explicit feedback 2280 is sent (for example, the address of initiator STA1 2210).

[0055] Figure 25 illustrates a sensing procedure relating to this disclosure that utilizes a staggered PPDU to request feedback. Additional signaling is required for the responding STA (STA3 830) to know about the staggered sounding PPDU 2510. When the threshold is exceeded, STA3 830 notifies STA1 810 of the threshold exceedance in block Ack 1405. STA1 810 sends a sensing request 1410 indicating explicit feedback to STA3 830. In a subsequent transmission, STA1 810 sends the staggered sounding PPDU 2510 (i.e., a PPDU with additional LTFs) for full channel sounding. Upon receiving the staggered sounding PPDU 2510, STA3 830 sends explicit feedback 1440 to STA1 810. Using the staggered PPDU2510 for full-channel measurements can eliminate the need for NDP sounding sequences and may be useful for full-channel measurements along with data communication.

[0056] Figure 26 is an illustration of a sensing procedure similar to the sensing procedure in Figure 2550, where, in accordance with this disclosure, an EHT (extra high throughput) PPDU 2610 is used instead of a staggered PPDU 2510 to request feedback.

[0057] Figure 27A is an illustration of an 802.11be EHT PPDU2710 used as EHT PPDU2610 in the sensing procedure illustrated 2600 relating to this disclosure. 802.11be defines the EHT PPDU2710 such that the number of EHT-LTF2720 contained therein may be independent of the number of STS, which helps in estimating the complete channel. Figure 27B is an illustration of an HT (high throughput) PPDU2760 which can be used as an alternative to EHT PPDU2610 in the sensing procedure illustrated 2600 relating to this disclosure.

[0058] Figure 28 illustrates a beamforming procedure using a sensing procedure with an access point AP2810 and a radio station STA2820 according to this disclosure. Channel measurement using a standard PPDU2830 according to this disclosure can also trigger the beamforming procedure. AP2810 can measure the uplink channel, and STA2820 can measure the downlink channel. Based on the LTF difference, the beamforming procedure may be initiated by AP2810.

[0059] Returning to Figure 100 (Figure 1), the steps involved in threshold-based WLAN sensing are described below. Each AP110 calculates a threshold for the STA120 associated with it (i.e., within its associated service area 115). The AP110 may inform the STA120 of the threshold using a beacon frame or a unicast management frame. Once the threshold is set for the STA120, the STA120 performs channel measurements during normal communication to check for threshold exceedance. In Figure 100, AP4 110d and STA4 120d detect a change in channel due to the presence of person 135. Therefore, the threshold for STA4 120d is exceeded based on the specific sensing capabilities of AP4 110d and STA4 120d. Then, full channel measurements are performed for AP4 110d and STA4 120d, and the results may be sent to the initiator (AP110 / STA120 / server 130).

[0060] Figure 29 illustrates conventional WLAN sensing. Unlike WLAN sensing according to this disclosure, channel measurement is not performed during a portion of conventional communication, and the overhead of checking thresholds unfavorably interrupts normal communication.

[0061] Figure 30 is an illustration of the WLAN sensing according to this disclosure. By using the threshold-based WLAN sensing according to this disclosure, channel measurement 3010 can be advantageously performed using a normal PPDU during normal communication 3015, reducing the overhead of the full channel sounding sequence for channel measurement without reducing normal communication time. Since full channel measurement is performed only when the threshold is exceeded, unnecessary sounding-related frame exchanges are suppressed, which has the advantage of reducing overhead. When a threshold exceedance is detected, WLAN sensing 3020 is performed according to this disclosure.

[0062] Figure 31 is a block diagram 3100 of a WLAN sensing device 3110 according to the present disclosure. As described above, the WLAN sensing device 3110 may be an access point (AP) 110 (Figure 1) including a control unit 252, a transmit / receive circuit 254, and an antenna 256 (Figure 2B), or it may be a wireless station (STA) 120 including a control unit 202, a transmit / receive circuit 204, and an antenna 206 (Figure 2A). For simplicity, the WLAN sensing device 3110 is assumed to be an AP 110 which may be an initiator or responder according to the present disclosure, but those skilled in the art will understand that the WLAN portions of the transmit / receive circuit 254 and the control unit 256 are similarly present in the transmit / receive circuit 204 and the control unit 206 of the STA 120.

[0063] Within the transmit / receive circuit 254, the station management entity (SME) 3120 manages the MLME 3130 via the MAC sublayer management entity (MLME) service access point (MLME SAP) 3122 and manages the PLME 3140 via the PHY sublayer management entity (PLME) service access point (PLME SAP) 3124. According to this disclosure, the MLME 3130 communicates with the WLAN sensing application 3150 in the control unit 252 via the SENSE SAP 3152. The MLME 3130 performs WLAN sensing according to this disclosure in the sensing module 3132 and, when operating as an initiator, calculates the threshold for the associated STA 120 in the sensing threshold module 3134. MLME3130 communicates with PLME3140 via MLME-PLME SAP3142 for normal communication and with PLME3140 via SENSE-PLME SAP3144 for WLAN sensing as described herein. MAC sublayer 3160 and PHY sublayer 3170 are encoded or decoded under the control of MLME3130 and PLME3140, respectively, in a manner well known to those skilled in the art, for transmission from or reception by WLAN sensing device 3110.

[0064] In a simple use case / deployment, the entire WLAN sensing platform can be implemented in a single device. Figure 32 shows a block diagram 3200 of a WLAN sensing system implemented in a single device 3210 according to this disclosure. Within the control unit 252, multiple WLAN sensing client applications 3220 perform WLAN sensing based on channel measurements (e.g., using application-specific machine learning algorithms) and provide WLAN sensing results (e.g., presence / absence, human movement) to a WLAN sensing application such as WLAN sensing application 3150 (Figure 31). The WLAN sensing application 3150 collects and integrates channel measurement results from 802.11 devices. The WLAN sensing application 3150 may process the results (e.g., by smoothing or compression) before passing them to the WLAN sensing client applications 3220. In the transceiver unit 254, the sensing module 3132 performs channel measurements and provides the raw results to the WLAN sensing application 3150. The sensing threshold module 3134 performs threshold calculations and provides the threshold set in the STA to the WLAN sensing MAC.

[0065] Referring to Figure 33, block diagram 3300 shows a configuration of a centralized multi-device implementation of a WLAN sensing system according to the present disclosure. The centralized WLAN sensing system includes a server 130 (Figure 1) that communicates with a WLAN sensing device 3110 (e.g., STA120) via an access point 110. The server 130 hosts a WLAN sensing client application 3310 that enables the use of more advanced WLAN sensing algorithms. Furthermore, in the centralized WLAN sensing system, the server 130 may perform threshold calculations for associated APs.

[0066] In a centralized WLAN sensing system, the WLAN sensing application 3150 may require more advanced processing of channel measurement results (e.g., smoothing or compression) to reduce the traffic load on the network infrastructure. To address this, the WLAN sensing device 3110 may have a threshold calculation subsystem.

[0067] Accordingly, it can be seen that the exemplary embodiments relating to this disclosure provide multiple configurations and methods that enable threshold-based methods for performing WLAN sensing using a standard PPDU. Conventional WLAN sensing has proposed threshold-based methods that perform WLAN sensing by sending NDP frames to determine whether a threshold has been exceeded, but the scheduled transmission of NDPs incurs overhead on data communications and interferes with ongoing data communications. However, the WLAN sensing relating to this disclosure reduces data communication overhead because full channel measurement is performed only after the threshold has been exceeded, and therefore, NDP transmission is not required until the threshold is exceeded.

[0068] This disclosure can be implemented by software, hardware, or software that interacts with hardware. Each functional block used in the description of each embodiment described above can be implemented partially or entirely by an LSI (Large Scale Integration) such as an integrated circuit, and each process described in each embodiment may be controlled partially or entirely by the same LSI or a combination of LSIs. The LSI may be formed as individual chips, or a single chip may be formed to include some or all of the functional blocks. The LSI may include data inputs and outputs coupled thereto. Here, LSIs may be called ICs, system LSIs, super LSIs, or ultra LSIs depending on the degree of integration. However, the technology for realizing integrated circuits is not limited to LSIs, and may be implemented using dedicated circuits, general-purpose processors, or application-specific processors. Furthermore, a Field Programmable Gate Array (FPGA) that can be programmed after manufacturing of an LSI or reconfigurable processor in which the connections and settings of circuit cells arranged inside the LSI can be reconfigured may be used. This disclosure can be implemented as digital processing or analog processing. As a result of advancements in semiconductor technology and other derivative technologies, if future integrated circuit technology replaces LSIs, functional blocks can be integrated using future integrated circuit technology. Biotechnology can also be applied.

[0069] This disclosure can be implemented by any type of device, apparatus, or system having communication capabilities, referred to as a communication apparatus. The communication apparatus may have a transceiver and a processing / control circuit. The transceiver may have and / or function as a receiver and a transmitter. The transceiver as a transmitter and receiver may include an RF (Radio Frequency) module including an amplifier, an RF modulator / demodulator, etc., and one or more antennas. The processing / control circuit may include a power management circuit which may include a dedicated circuit, a processor, and instructions for power management control as either firmware or instructions stored in memory provided in the processor.

[0070] Some non-exclusive examples of such communication devices include telephones (e.g., cell 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 telemedicine) devices, and vehicles providing communication capabilities (e.g., automobiles, airplanes, ships), as well as various combinations thereof.

[0071] Communication devices are not limited to being portable or mobile, and may include any type of device, device, or system that is non-portable or fixed, such as smart home devices (e.g., appliances, lighting, smart meters, control panels), vending machines, and any other “thing” in the “Internet of Things (IoT)” network. Communication may include exchanging data via, for example, cellular systems, wireless LAN systems, satellite systems, and various combinations thereof.

[0072] The communication device may include devices such as controllers or sensors coupled to a communication device that performs the communication functions described in this disclosure. For example, the communication device may include controllers or sensors that generate control signals or data signals used by the communication device that performs the communication functions of the communication device.

[0073] The communication equipment may also include infrastructure facilities such as base stations and access points, and any other equipment, devices, or systems that communicate with or control such equipment as those in the non-limiting examples above.

[0074] While exemplary embodiments have been shown in the above-mentioned detailed description of the present invention, it should be understood that a vast number of modifications are possible. Furthermore, it should be understood that these embodiments are merely illustrative and are not intended to limit in any way the scope, applicability, operation, or configuration of the present disclosure. Rather, it should be understood that the above-mentioned detailed description provides a useful roadmap for realizing the exemplary embodiments, and that various modifications can be made to the functions and arrangements of the STA and / or AP communication devices described in the exemplary embodiments without departing from the spirit of the present disclosure as set forth in the appended claims.

[0075] 1. During operation, the transceiver unit receives signals via a wireless local area network (WLAN), During operation, a circuit demodulates and decodes the aforementioned signal, A communication device equipped with, The decoded signal includes a first PPDU (physical layer protocol data unit) and a second PPDU. During operation, the circuit performs full-channel measurement based on the first PHY (physical layer) header of the first PPDU and the second PHY header of the second PPDU. The first PHY header and the second PHY header include an LTF (long training field) for estimating channel quality. Communication device.

[0076] 2. The communication device according to claim 1, wherein the second PPDU is received by the transmitting / receiving unit following the first PPDU.

[0077] 3. The communication device according to claim 2, wherein the circuit performs a full channel measurement based on the difference between the first PPDU and the second PPDU during operation.

[0078] 4. The communication device according to claim 1 or 2, wherein the circuit calculates a first channel measurement parameter based on the first PPDU and a second channel measurement parameter based on the second PPDU during operation.

[0079] 5. The communication device according to claim 4, wherein the circuit performs a full channel measurement based on the difference between the first channel measurement parameter and the second channel measurement parameter during operation.

[0080] 6. The communication device according to claim 4 or 5, wherein the first channel measurement parameter includes first channel state information, and the second channel measurement parameter includes second channel state information.

[0081] 7. The communication device according to claim 4 or 5, wherein the first channel measurement parameter and the second channel measurement parameter include one of the time reversal resonating strength (TRRS), signal-to-noise ratio (SNR), and detected channel energy.

[0082] 8. The communication device according to any one of claims 5 to 7, wherein the circuit performs a full channel measurement based on the difference between the first channel measurement parameter and the second channel measurement parameter that exceeds a threshold during operation.

[0083] 9. The communication device according to claim 8, wherein the circuit generates a threshold exceedance notification based on the difference between the first channel measurement parameter and the second channel measurement parameter that exceeds the threshold during operation, and the transmitting / receiving unit transmits the threshold exceedance notification in an uplink frame during operation.

[0084] 10. The communication device according to claim 9, wherein the frame of the uplink is one of a block ack frame, a sounding frame, and a unicast action frame.

[0085] 11. The communication device according to any one of claims 8 to 10, wherein the transmitting and receiving unit receives a threshold signal in one of a beacon frame, a unicast management frame, and a probe response frame during operation, and the circuit demodulates and decodes the threshold signal in order to obtain the threshold during operation.

[0086] 12. The communication device according to any one of claims 1 to 11, wherein the circuit initiates a beamforming procedure based on the first PHY header of the first PPDU and the second PHY header of the second PPDU when in operation.

[0087] 13. During operation, the transceiver unit receives signals on a wireless local area network (WLAN), During operation, a circuit demodulates and decodes the aforementioned signal, A communication device equipped with, The decoded signal includes a threshold exceedance notification from the associated communication device. When operating, the circuit initiates a WLAN sensing procedure to perform a full channel measurement based on a threshold exceedance notification from the associated communication device. Communication device.

[0088] 14. The communication device according to claim 13, wherein the communication device functions as a WLAN sensing initiator, and the associated communication device functions as a WLAN sensing responder.

[0089] 15. The communication device according to claim 13 or 14, wherein the notification of the threshold being exceeded by the associated communication device is received in a block Ack frame.

[0090] 16. The communication device according to any one of claims 13 to 15, wherein the decoded signal includes a PPDU (physical layer protocol data unit), and the circuit, when in operation, initiates a WLAN sensing procedure to perform a full channel measurement based on the PPDU indicating a threshold exceedance by the associated communication device.

[0091] 17. The communication device according to any one of claims 13 to 16, wherein the circuit initiates the WLAN sensing procedure by generating a sensing request frame including a WLAN sensing request when in operation, and the transmitting / receiving unit transmits the sensing request frame to the associated communication device.

[0092] 18. The communication device according to claim 17, wherein the sensing request frame requests feedback from the associated communication device.

[0093] 19. The communication device according to claim 18, wherein the requested feedback includes one of NDP (null data packet), partial feedback, and explicit feedback.

[0094] 20. The communication device according to claim 19, wherein the circuit, when in operation, performs the full channel measurement based on the requested feedback, including NDP.

[0095] 21. The communication device according to claim 19, wherein the circuit, when in operation, performs a full channel measurement and generates an NDP for transmission to the associated communication device in order to provide explicit channel measurement feedback based on the requested feedback, including explicit feedback.

[0096] 22. The communication device according to claim 21, wherein the circuit further generates a staggered PPDU including an additional LTF (long training field) for transmission to the associated communication device in order to provide the explicit channel measurement feedback during operation.

[0097] 23. The communication device according to claim 19, wherein the decoded signal includes channel quality information of the long training field (LTF) contained in the PPDU received by the associated communication device, based on the requested feedback, which includes partial feedback.

[0098] 24. A communication method in a wireless local area network (WLAN), comprising the step of performing a full channel measurement according to a first PHY (physical layer) header of a first PPDU (physical layer protocol data unit) and a second PHY header of a second PPDU, wherein the first PHY header and the second PHY header include an LTF (long training field) for estimating channel quality, the second PPDU is received following the first PPDU, and the step of performing the full channel measurement is based on the difference between the first PPDU and the second PPDU.

[0099] 25. A step of calculating a first channel measurement parameter based on the first PPDU, A communication method according to claim 24, further comprising the step of calculating a second channel measurement parameter based on the second PPDU, wherein the step of performing a full channel measurement is based on the difference between the first channel measurement parameter and the second channel measurement parameter.

[0100] 26. The communication method according to claim 25, wherein the first channel measurement parameter includes first channel state information, and the second channel measurement parameter includes second channel state information.

[0101] 27. The communication method according to claim 25 or 26, wherein the first channel measurement parameter and the second channel measurement parameter include one of the time reversal resonating strength (TRRS), signal-to-noise ratio (SNR), and detected channel energy.

[0102] 28. The communication method according to any one of claims 25 to 27, wherein the step of performing a full channel measurement includes the step of performing a full channel measurement based on the difference between the first channel measurement parameter and the second channel measurement parameter that exceeds a threshold.

[0103] 29. The communication method according to claim 28, further comprising the step of sending a threshold exceedance notification in an uplink frame based on the difference between the first channel measurement parameter and the second channel measurement parameter that exceeds the threshold.

[0104] 30. The communication method according to claim 29, wherein the uplink frame is one of a block ack frame, a sounding frame, and a unicast action frame.

[0105] 31. The communication method according to any one of claims 28 to 30, further comprising the step of receiving a threshold signal in one of a beacon frame, a unicast management frame, and a probe response frame.

[0106] 32. The communication method according to any one of claims 24 to 30, further comprising the step of initiating a beamforming procedure based on the first PHY header of the first PPDU and the second PHY header of the second PPDU.

[0107] 33. A communication method in a wireless local area network (WLAN), comprising the steps of: receiving a threshold exceedance notification from an associated communication device; and initiating a WLAN sensing procedure to perform a full channel measurement based on the threshold exceedance notification from the associated communication device.

[0108] 34. The communication method according to claim 33, wherein the step of initiating a WLAN sensing procedure includes the step of initiating a WLAN sensing procedure to perform a full channel measurement based on a PPDU (physical layer protocol data unit) indicating a threshold exceedance by the associated communication device.

[0109] 35. The communication method according to claim 33 or 34, wherein the step of initiating the WLAN sensing procedure includes transmitting a sensing request frame containing a WLAN sensing request to the associated communication device.

[0110] 36. The communication method according to claim 35, wherein the step of transmitting the sensing request frame to the associated communication device includes the step of requesting feedback from the associated communication device.

[0111] 37. The communication method according to claim 36, wherein the step of requesting feedback from the associated communication device includes the step of requesting one of NDP (null data packet), partial feedback, and explicit feedback from the associated communication device.

[0112] 38. The communication method according to claim 37, wherein the step of requesting an NDP from the associated communication device includes the step of performing the full channel measurement.

[0113] 39. The communication method according to claim 37, wherein the step of requesting explicit feedback from the associated communication device includes the step of performing the full channel measurement and generating an NDP for transmission to the associated communication device in order to provide explicit channel measurement feedback.

[0114] 40. The communication method according to claim 39, wherein the step of requesting explicit feedback from the associated communication device further includes the step of transmitting a staggered PPDU including an additional LTF (long training field) to the associated communication device in order to provide the explicit channel measurement feedback.

[0115] 41. The step of requesting partial feedback from the associated communication device is: The steps include transmitting the LTF (long training field) contained in the PPDU to the associated communication device, The communication method according to claim 37, comprising the step of receiving channel quality information of the LTF from the associated communication device.

Claims

1. During operation, the system includes a transceiver that receives signals via a wireless local area network (WLAN), During operation, a circuit demodulates and decodes the aforementioned signal, A communication device equipped with, The decoded signal includes a notification from the associated communication device that a threshold has been exceeded for WLAN sensing. The circuit, when operating, generates a request frame requesting feedback from the associated communication device based on the notification of exceeding the threshold, and transmits the request frame to the associated communication device. Communication device.

2. The circuit, when operating, initiates a WLAN sensing procedure to perform a full channel measurement based on a notification of exceeding the threshold. The communication device according to claim 1.

3. The request frame is a sensing request frame that includes a WLAN sensing request, The circuit starts the WLAN sensing procedure by generating the sensing request frame during operation. The transmitting / receiving unit transmits the sensing request frame to the associated communication device. The communication device according to claim 2.

4. The circuit performs the full-channel measurement when in operation. The communication device according to claim 2.

5. The circuit, when operating, performs a full channel measurement and generates an NDP for transmission to the associated communication device in order to provide explicit channel measurement feedback based on the requested feedback, including explicit feedback. The communication device according to claim 1.

6. The circuit, during operation, further generates staggered PPDUs for transmission to the associated communication device in order to provide the explicit channel measurement feedback. The communication device according to claim 5.

7. The decoded signal includes channel quality information of the LTF (long training field) contained in the PPDU received by the associated communication device, based on the requested feedback, including partial feedback. The communication device according to claim 1.

8. An integrated circuit for controlling a communication device, The process of receiving signals on a wireless local area network (WLAN), Control the process of demodulating and decoding the aforementioned signal, The decoded signal includes a notification from the associated communication device that a threshold has been exceeded for WLAN sensing. Based on the notification of exceeding the threshold, the system controls the process of generating a request frame requesting feedback from the associated communication device and transmitting the request frame to the associated communication device. Integrated circuit.

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