Channel state information (CSI) reporting for radio frequency (RF) sensing

Abstract

This application provides systems, methods, and apparatus for reporting Channel Status Information (CSI), including computer programs encoded on a computer storage medium. In some embodiments, a receiving device may acquire a set of Channel Frequency Response (CFR) values ​​associated with one or more probe packets received from a transmitting device, and may classify the set of CFR values ​​into multiple subsets based on a number of transmitting antennas of the transmitting device, a number of receiving antennas of the receiving device, or a number of tones across the bandwidth of a wireless channel. In this embodiment, the receiving device may transmit one or more CSI report frames, each carrying a corresponding subset of CFR values. In some other embodiments, the receiving device may acquire multiple CSIs associated with corresponding probe packets and may transmit a single CSI report frame carrying the CSI for each wireless channel.

Description

[Technical Field]

[0001] This patent application claims priority to Indian Patent Application No. 202141032188, filed on July 16, 2021, entitled “CHANNEL STATE INFORMATION (CSI) REPORTING FOR RADIO FREQUENCY (RF) SENSING,” which has been assigned to the assignee of this application. All disclosures of prior applications are considered part of this patent application and are incorporated herein by reference.

[0002] The following content is generally about radio frequency (RF) sensing, and more specifically about channel status information (CSI) reporting technology used for RF sensing. [Previous Technology]

[0003] Wireless communication devices communicate by transmitting and receiving electromagnetic signals in the radio frequency (RF) spectrum. The operating environment of a wireless communication device affects the propagation of electromagnetic signals. For example, electromagnetic signals transmitted by a transmitting device may be reflected from objects and surfaces in the environment before reaching a distant receiving device. Therefore, the amplitude or phase of the electromagnetic signal received by the receiving device can depend at least in part on the characteristics of the environment.

[0004] Radio frequency sensing is a technique for sensing objects or motion in an environment, at least in part, based on the transmission and reception of electromagnetic signals. More specifically, changes in the environment can be detected based on changes in electromagnetic signals (e.g., phase or amplitude) propagating in the environment. For example, a person moving in the environment interferes with electromagnetic signals transmitted by a transmitting device. A receiving device can detect and characterize such changes in the signals it receives to determine the speed or direction of the person's movement. [Summary of the Invention]

[0005] The systems, methods and apparatuses contained in this case each have several inventive forms, and no single inventive form is solely responsible for the desired properties disclosed herein.

[0006] One innovative aspect of the subject matter described in this case can be implemented as a wireless communication method. This method can be performed by a wireless communication device to report channel status information (CSI) of a wireless channel. In some embodiments, the method may include the following steps: receiving one or more probe packets from a transmitting device via a wireless channel; acquiring channel status information (CSI) associated with the one or more probe packets, wherein the CSI includes a set of values ​​categorized into multiple subsets based on a number (M) of transmitting antennas of the transmitting device, a number (N) of receiving antennas of the wireless communication device, or a number (K) of tones across the bandwidth of the wireless channel, wherein each of the equivalent values ​​indicates a channel frequency response (CFR) associated with a corresponding transmitting antenna among the M transmitting antennas, a corresponding receiving antenna among the N receiving antennas, and a corresponding tone among the K tones; and transmitting one or more CSI report frames, each CSI report frame carrying a corresponding subset of values ​​from the multiple subsets.

[0007] Another innovative aspect of the subject matter described in this case can be implemented in a wireless communication device. The wireless communication device may include: an interface configured to receive one or more probe packets from a transmitting device via a wireless channel; and a processing system configured to: acquire a CSI associated with the one or more probe packets, wherein the CSI includes a set of values ​​categorized into multiple subsets based on a number (M) of transmitting antennas of the transmitting device, a number (N) of receiving antennas of the wireless communication device, or a number (K) of tones across the bandwidth of the wireless channel, wherein each of the equivalent values ​​indicates a CFR associated with a corresponding transmitting antenna among the M transmitting antennas, a corresponding receiving antenna among the N receiving antennas, and a corresponding tone among the K tones; and wherein the interface is further configured to transmit one or more CSI report frames, each CSI report frame carrying a corresponding subset of values ​​from the multiple subsets.

[0008] Another innovative aspect of the subject matter described in this case can be implemented as a wireless communication method. This method can be performed by a wireless communication device to report CSI of a wireless channel. In some embodiments, the method may include the following steps: receiving a first probe packet via a first wireless channel; acquiring a first CSI associated with the first probe packet; receiving a second probe packet via a second wireless channel; acquiring a second CSI associated with the second probe packet; and transmitting a CSI report frame, the CSI report frame including a first report field carrying the first CSI and a second report field carrying the second CSI.

[0009] Another innovative aspect of the subject matter described in this case can be implemented in a wireless communication device. The wireless communication device may include: an interface configured to receive a first probe packet via a first wireless channel and a second probe packet via a second wireless channel; and a processing system configured to acquire a first CSI associated with the first probe packet and a second CSI associated with the second probe packet; and wherein the interface is further configured to transmit a CSI report frame, the CSI report frame including a first report field carrying the first CSI and a second report field carrying the second CSI.

[0010] Details of one or more embodiments of the subject matter described in this document are set forth in the accompanying drawings and the following description. Other features, features, and advantages will become apparent from the specification, drawings, and claims. Note that the relative dimensions in the following drawings may not be drawn to scale.

Implementation Method

[0029] To describe the innovative nature of this invention, the following description pertains to certain specific implementations. However, those skilled in the art will readily recognize that the teachings herein can be applied in a variety of different ways. The described implementations can be implemented in any device, system, or network capable of transmitting and receiving radio frequency (RF) signals according to one or more of the Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards issued by the 3GPP, the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, or the Bluetooth® standard defined by the Bluetooth Special Interest Group (SIG), etc. The described implementations can be implemented in any device, system, or network capable of transmitting and receiving RF signals according to one or more of the following technologies or methods: Code Division Multiple Access (CDMA), Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Orthogonal FDMA (OFDMA), Single Carrier FDMA (SC-FDMA), Single User (SU) Multiple Input Multiple Output (MIMO), and Multiple User (MU) MIMO. The described implementation can also be implemented using other wireless communication protocols or RF signals suitable for use in one or more of wireless wide area networks (WWAN), wireless personal area networks (WPAN), wireless local area networks (WLAN), or Internet of Things (IoT) networks.

[0030] Existing versions of the IEEE 802.11 standard provide channel probing procedures for capturing or acquiring Channel State Information (CSI). CSI describes how a signal propagates through a wireless channel between a transmitting and receiving device. Therefore, CSI is well-suited for radio frequency (RF) sensing applications. CSI is typically represented by a three-dimensional matrix, where each entry in the matrix indicates the channel frequency response (CFR) associated with the corresponding transmitting antenna of the transmitting device, the corresponding receiving antenna of the receiving device, and the corresponding tone or subcarrier of the wireless channel. However, for some RF sensing applications, this level of detail may not be necessary.

[0031] The channel probing procedure can be performed as follows: a transmitting (TX) device transmits a signal of a known pattern or sequence to a receiving (RX) device via a wireless channel, and the receiving (RX) device captures or acquires the CSI based on the received signal. More specifically, the RX device can compare the received signal with a known pattern or sequence to determine the effect of the wireless channel on signal propagation. Therefore, the CSI can be a matrix representation of the wireless channel, where each entry in the matrix represents the CFR for a corresponding tone or subcarrier of the wireless channel between the corresponding transmitting antenna of the TX device and the corresponding receiving antenna of the RX device. Therefore, each entry in the CSI matrix may be referred to herein as a "CFR value". In some cases, the "responder" of the channel probing (which may be the RX device or another device working with the RX device) can report the captured CSI to the "initiator" of the channel probing (which may be the TX device or another device working with the TX device) via a management frame.

[0032] The size of the CSI depends on the bandwidth of the wireless channel and the number of antennas used for transmitting and receiving wireless signals. However, the payload size of the management frame is limited to 11,454 bytes. CSIs exceeding the maximum payload size of the management frame can be segmented for transmission across multiple management frames. According to existing versions of the IEEE 802.11 standard (e.g., IEEE 802.11ax revision), each segment, except for the last segment (which may be smaller), must be 11,454 bytes long. Therefore, each management frame may not be able to carry a subset of the properly defined (or described) CFR values. In other words, the initiating party must first receive each segment before interpreting the associated CSI. However, various aspects of this application recognize that a full CSI report may not be necessary for some RF sensing applications. For example, the presence or movement of an object can be detected based on changes in the wireless channel. Such changes can be detected in any tone (or subset of tone) across the wireless channel bandwidth and for any combination of transmitting and receiving antennas. Therefore, RF sensing requires new CSI reporting technology.

[0033] The embodiments of the subject matter described in this document can be used to report CSI for RF sensing applications. In some embodiments, the RX device can acquire a set of CFR values ​​(representing CSI) associated with one or more probe packets received from the TX device via a wireless channel, and classify the set of CFR values ​​into multiple subsets based on a number (M) of transmit antennas of the TX device, a number (N) of receive antennas of the RX device, or a number (K) of tones across the wireless channel bandwidth. Therefore, the RX device can transmit one or more CSI report frames, each carrying a corresponding subset of CFR values. In some embodiments, each subset of CFR values ​​can be associated with a corresponding subset of K tones, a corresponding subset of M transmit antennas, or a corresponding subset of N receive antennas. In some other embodiments, a first component (e.g., an amplitude component or an in-phase (I) component) of one or more CFR values ​​can be classified into a subset different from a second component (e.g., a phase component or a quadrature (Q) component) of the one or more CFR values.

[0034] In some other embodiments, the RX device can acquire multiple CSIs associated with corresponding probe packets received via multiple radio channels, and can transmit a single CSI report frame carrying the CSI for each radio channel. For example, each CSI can be carried in a corresponding report field of the CSI report frame. In some embodiments, the CSI report frame can further include multiple control fields, each carrying relay data associated with the CSI of the corresponding radio channel. In some embodiments, the control field and report field associated with a given radio channel can be included in the same information element (IE) within the frame body of the CSI report frame. In some other embodiments, each report field can immediately follow the corresponding control field in the frame body of the CSI report frame. In this embodiment, each control field can further carry length information indicating the length of the report field that follows it. Furthermore, in some embodiments, a separator can be added to the frame body of the CSI report frame to signal the start (or end) of each pair of control and report fields.

[0035] Specific implementations of the subject matter described herein can be implemented to achieve one or more of the following potential advantages. By classifying CFR values ​​into multiple subsets, the various forms of the present invention can allow for efficient reporting of CSIs for RF sensing applications. For example, the size of each subset of CFR values ​​can be adapted to be transmitted in a single management frame. Unlike the segmentation techniques defined in existing versions of the IEEE 802.11 standard, each CSI reporting frame in the embodiments herein can include a properly defined subset of CFR values. As a result, the initiator can perform at least a portion of the RF sensing operation in response to each CSI reporting frame received from the RX device (without having to receive each CSI reporting frame associated with a given radio channel). By including multiple CSIs in a single CSI reporting frame, the various forms of the present invention can further reduce the signal transmission management burden associated with CSI reporting. For example, each CSI carried in the CSI report can be associated with a different radio channel. Therefore, the initiator can perform RF sensing in multiple radio channels in response to a single CSI reporting frame.

[0036] FIG1 illustrates a block diagram of an exemplary wireless system 100. The wireless system 100 is illustrated as including a wireless access point (AP) 110 and multiple wireless stations (STAs) 120a–120i. For simplicity, one AP 110 is illustrated in FIG1. ​​The AP 110 may form a wireless local area network (WLAN), which allows the AP 110, STAs 120a–120i and other wireless devices (not illustrated for simplicity) to communicate with each other via a wireless medium. The wireless medium may be divided into multiple channels or multiple resource elements (RUs), which may facilitate wireless communication between the AP 110, STAs 120a–120i and other wireless devices connected to the WLAN. In some embodiments, STAs 120a–120i may communicate with each other using peer communication (e.g., in the absence of AP 110 or without AP 110's participation). For example, the access point manufacturer can assign a unique MAC address to AP 110, which is programmed into AP 110. Similarly, each of STA 120a–120i can also be assigned a unique MAC address.

[0037] In some embodiments, the wireless system 100 may correspond to a multiple-input multiple-output (MIMO) wireless network and may support single-user MIMO (SU-MIMO) and multi-user (MU-MIMO) communication. In some embodiments, the wireless system 100 may support orthogonal frequency division multiple access (OFDMA) communication. Furthermore, although the WLAN is described as an Infrastructure Basic Services Set (BSS) in FIG1, in some other embodiments, the WLAN may be an Independent Basic Services Set (IBSS), an Extended Services Set (ESS), an ad hoc network, or a peer-to-peer (P2P) network (e.g., operating according to one or more Wi-Fi Direct protocols).

[0038] STA 120a–120i can be any suitable Wi-Fi-enabled wireless device, including, for example, mobile phones, personal digital assistants (PDAs), tablet devices, laptops, etc. STA 120a–120i can also be referred to as user equipment (UE), user station, mobile unit, user unit, radio unit, remote unit, mobile device, wireless device, wireless communication device, remote device, mobile user station, access terminal, mobile terminal, wireless terminal, remote terminal, handheld device, user agent, mobile service client, client, or some other suitable terminology.

[0039] AP 110 can be any suitable device that allows one or more wireless devices (e.g., STA 120a–120i) to connect to another network (e.g., a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), or the Internet). In some embodiments, system controller 130 can facilitate communication between AP 110 and other networks or systems. In some embodiments, system controller 130 can facilitate communication between AP 110 and one or more other APs (not shown for simplicity), which may be associated with other wireless networks. Furthermore, or alternatively, AP 110 can use wireless communication to exchange signals and information with one or more other APs.

[0040] AP 110 can periodically broadcast beacon frames to enable STA 120a–120i and other wireless devices within AP 110's wireless range to establish and maintain communication links with AP 110. Beacon frames can indicate downlink (DL) data transmissions to STA 120a–120i and request or schedule uplink (UL) data transmissions from STA 120a–120i. Beacon frames are typically broadcast according to the Target Beacon Transmission Time (TBTT) schedule. The broadcast beacon frames may include AP 110's Timing Synchronization Function (TSF) value. For example, STA 120a–120i can synchronize its own local TSF value with the broadcast TSF value so that all STA 120a–120i are synchronized with each other and with AP 110.

[0041] In some embodiments, each of the stations STA 120a–120i and AP 110 may include one or more transceivers, one or more processing resources (e.g., processors or application-specific integrated circuits (ASICs)), one or more memory resources, and a power supply (e.g., a battery). The one or more transceivers may include Wi-Fi transceivers, Bluetooth transceivers, cellular transceivers, or other suitable radio frequency (RF) transceivers (not illustrated for simplicity) for transmitting and receiving wireless communication signals. In some embodiments, each transceiver may communicate with other wireless devices in different frequency bands or using different communication protocols. Memory resources may include non-transitory computer-readable media (e.g., one or more non-volatile memory elements, such as EPROM, EEPROM, flash memory, hard disks, etc.) storing instructions for performing operations for one or more of Figures 5–11.

[0042] FIG2 illustrates an exemplary wireless station (STA) 200. STA 200 may be an implementation of at least one of the STAs 120a–120i of FIG1. ​​STA 200 may include one or more transceivers 210, a processor 220, a user interface 230, memory 240, and several antennas ANT1–ANTn. Transceivers 210 may be coupled directly to antennas ANT1–ANTn or via antenna selection circuitry (not shown for simplicity). Transceivers 210 may be used to transmit signals to and receive signals from other wireless devices, including, for example, several APs and several other STAs. Although not illustrated in FIG2 for simplicity, transceivers 210 may include any number of transmission chains to process signals and transmit signals to other wireless devices via antennas ANT1–ANTn, and may include any number of receive chains to process signals received from antennas ANT1–ANTn. Therefore, STA 200 may be configured for MIMO communication and OFDMA communication. MIMO communication can include SU-MIMO communication and MU-MIMO communication. In some implementations, STA 200 can use multiple antennas ANT1-ANTn to provide antenna diversity. Antenna diversity can include polarization diversity, mode diversity, and spatial diversity.

[0043] Processor 220 may be any suitable one or more processors capable of executing scripts or instructions of one or more software programs stored in STA 200 (e.g., within memory 240). In some embodiments, processor 220 may be or may include one or more microprocessors providing processor functionality and external memory providing at least a portion of machine-readable medium. In other embodiments, processor 220 may be or may include application-specific integrated circuits (ASICs) having a processor, bus interface, user interface, and at least a portion of machine-readable medium integrated into a single chip. In some other embodiments, processor 220 may be or may include one or more field-programmable gate arrays (FPGAs) or programmable logic devices (PLDs).

[0044] In some embodiments, processor 220 may be an element of a processing system. A processing system may generally refer to a system or family of machines or elements that receives input and processes input to produce a set of outputs (which may be passed to other systems or elements, such as other systems or elements of STA 200). For example, the processing system of STA 200 may refer to a system that includes various other elements or sub-elements of STA 200.

[0045] The processing system of STA 200 can be connected to other components of STA 200 via an interface and can process information received from other components (e.g., inputs or signals), output information to other components, etc. For example, the chip or modem of STA 200 can be coupled to or may include the processing system, a first interface for outputting information, and a second interface for acquiring information. In some examples, the first interface may refer to the interface between the processing system of the chip or modem and the transmitter, allowing STA 200 to transmit information output from the chip or modem. In some cases, the second interface may refer to the interface between the processing system of the chip or modem and the receiver, allowing STA 200 to receive information or signal input and to transmit information to the processing system. It will be readily recognized by those skilled in the art that the first interface can also receive information or signal input, and the second interface can also output information or signal output.

[0046] The user interface 230 coupled to the processor 220 may be or can represent several suitable user input devices, such as, for example, a speaker, microphone, display device, keyboard, touch screen, etc. In some embodiments, the user interface 230 may allow a user to control several operations of the STA 200, interact with one or more applications that can be executed by the STA 200, and other suitable functions.

[0047] In some embodiments, STA 200 may include a Satellite Positioning System (SPS) receiver 250. The SPS receiver 250, coupled to processor 220, may be used to acquire and receive signals transmitted from one or more satellites or satellite systems via an antenna (not shown for simplicity). The signals received by the SPS receiver 250 may be used to determine (or at least assist in determining) the location of STA 200.

[0048] Memory 240 may include device database 241, which may store location data, configuration information, data rate, media access control (MAC) address, timing information, modulation and decoding scheme (MCS), traffic indicator (TID) queue size, ranging capability, and other appropriate information about (or relating to) STA 200. Device database 241 may also store profile information for several other wireless devices. Profile information for a given wireless device may include, for example, the wireless device's Service Set Identifier (SSID), Basic Service Set Identifier (BSSID), operating channel, TSF value, beacon spacing, ranging schedule, Channel Status Information (CSI), Received Signal Strength Indicator (RSSI) value, effective transmission quantity value, and connection history with STA 200. In some embodiments, profile information for a given wireless device may also include clock offset value, carrier frequency offset value, and ranging capability.

[0049] The memory 240 may also be or may include a non-transitory computer-readable storage medium (e.g., one or more non-volatile memory elements, such as EPROM, EEPROM, flash memory, hard disk, etc.), which may store all or part of the computer-executable instructions 242 for performing one or more operations described in the present invention.

[0050] Figure 3 illustrates an exemplary access point (AP) 300. AP 300 may be an implementation of AP 110 of Figure 1. AP 300 may include one or more transceivers 310, a processor 320, memory 330, a network interface 340, and several antennas ANT1-ANTn. Transceivers 310 may be coupled directly to antennas ANT1-ANTn or via antenna selection circuitry (not shown for simplicity). Transceivers 310 may be used to transmit signals to and receive signals from other wireless devices, including, for example, one or more STAs 120a-120i and other APs of Figure 1. Although not illustrated in Figure 3 for simplicity, transceivers 310 may include any number of transmission chains to process signals and transmit signals to other wireless devices via antennas ANT1-ANTn, and may include any number of receive chains to process signals received from antennas ANT1-ANTn. Therefore, AP 300 may be configured for MIMO communication and OFDMA communication. MIMO communication can include SU-MIMO communication and MU-MIMO communication. In some implementations, AP 300 can use multiple antennas ANT1-ANTn to provide antenna diversity. Antenna diversity can include polarization diversity, mode diversity, and spatial diversity.

[0051] In high-frequency (e.g., 60 GHz or millimeter-wave (mmWave)) wireless communication systems (e.g., IEEE 802.11a1 or 802.11ay revisions conforming to the IEEE 802.11 standard), beamforming can be performed on the transmitter and receiver using phased array antennas. Beamforming generally refers to a wireless communication technique in which the transmitting and receiving devices adjust the settings of their transmitting or receiving antennas to achieve the link budget required for subsequent communication. The procedure of adjusting the transmitting and receiving antennas is called beamforming training, which can be initially performed to establish a link between the transmitting and receiving devices, and can also be performed periodically to maintain link quality using optimized transmitting and receiving beams.

[0052] Processor 320 may be any suitable one or more processors capable of executing scripts or instructions of one or more software programs stored in AP 300 (e.g., in memory 330). In some embodiments, processor 320 may be or may include one or more microprocessors providing processor functionality and external memory providing at least a portion of machine-readable medium. In other embodiments, processor 320 may be or may include an ASIC having at least a processor, bus interface, user interface, and machine-readable medium integrated into a single chip. In some other embodiments, processor 320 may be or may include one or more FPGAs or PLDs. In some embodiments, processor 320 may be an element of a processing system. For example, a processing system for AP 300 may refer to a system that includes various other elements or sub-elements of AP 300.

[0053] The processing system of AP 300 can be connected to other components of AP 300 via an interface, and can process information received from other components (e.g., inputs or signals), output information to other components, etc. For example, the chip or modem of AP 300 may include a processing system, a first interface for outputting information, and a second interface for acquiring information. In some examples, the first interface may refer to the interface between the processing system of the chip or modem and the transmitter, enabling AP 300 to transmit information output from the chip or modem. In some cases, the second interface may refer to the interface between the processing system of the chip or modem and the receiver, enabling AP 300 to acquire information or signal input and to transmit information to the processing system. Those skilled in the art will readily recognize that the first interface can also acquire information or signal input, and the second interface can also output information or signal output.

[0054] The network interface 340 coupled to the processor 320 can be used to communicate with the system controller 130 of FIG1. ​​The network interface 340 can also allow the AP 300 to communicate directly or via one or more intermediate networks with other wireless systems, other APs, one or more backhaul networks or any combination thereof.

[0055] Memory 330 may include device database 331, which may store location data, configuration information, data rate, MAC address, timing information, MCS, ranging capability, and other appropriate information about (or relating to) AP 300. Device database 331 may also store profile information of several other wireless devices (e.g., one or more of stations 120a–120i in FIG. 1). Profile information of a given wireless device may include, for example, the wireless device's SSID, BSSID, operating channel, CSI, Received Signal Strength Indicator (RSSI) value, valid transmission amount value, and connection history with AP 300. In some embodiments, profile information of a given wireless device may also include TID queue size, preferred packet duration for trigger-based UL transmission, and the maximum amount of queued UL data that the wireless device can insert into the TB-PPBU.

[0056] The memory 330 may also be or may include a non-transitory computer-readable storage medium (e.g., one or more non-volatile memory elements, such as EPROM, EEPROM, flash memory, hard disk, etc.), which may store all or part of the computer-executable instructions 332 for performing one or more operations described in the present invention.

[0057] Figures 4A and 4B illustrate an exemplary RF sensing system 400. The RF sensing system 400 includes a TX device 410 and an RX device 420. In some embodiments, the TX device 410 may be an instance of AP 110 of Figure 1 or AP 300 of Figure 3. In some other embodiments, the TX device 410 may be an instance of STA 120 of Figure 1 or STA 200 of Figure 2. In some embodiments, the RX device 420 may be an instance of AP 110 of Figure 1 or AP 300 of Figure 3. In some other embodiments, the RX device 420 may be an instance of STA 120 of Figure 1 or STA 200 of Figure 2. In the examples of Figures 4A and 4B, the TX device 410 is the initiator of a channel probe operation, and the RX device 420 is the responder of a channel probe operation.

[0058] Referring to FIG4A, TX device 410 may initiate channel probing operation by transmitting a probe packet 432 to RX device 420 via wireless channel 430. In some embodiments, probe packet 432 may be a null data packet (NDP) which includes, for example, a known pattern or sequence of training signals, such as in one or more long training fields (LTF). Some training signals may be reflected by objects or surfaces in the environment. As shown in FIG4A, a static object or surface 401 (e.g., a wall) reflects probe packet 432 in the direction of RX device 420. RX device 420 receives probe packet 432 and may extract or acquire CSI associated with wireless channel 430 by comparing the training signal (y) in the received probe packet 432 with its known value (x). CSI indicates how wireless channel 430 affects the propagation of signals transmitted from TX device 410 to RX device 420. Therefore, CSI can be modeled as a matrix (H), where y = H*x. In some implementations, the RX device 420 may transmit a CSI report 436, which includes the CSI associated with the wireless channel 430, back to the TX device 410.

[0059] Referring to FIG. 4B, a new object 402 (e.g., a person) may enter the environment of the RF sensing system 400. The TX device 410 may transmit another probe packet 442 to the RX device 420 in the presence of the object 402. The RX device 420 receives the probe packet 442 and may extract or acquire the CSI associated with the wireless channel 440 by comparing the training signal in the received probe packet 442 with its known value. Compared to FIG. 4A, the new object 402 may alter the propagation of at least some signals transmitted from the TX device 410 to the RX device 420. For example, the phase or amplitude of the training signal received (by the RX device 420) in the presence of the object 402 may differ from the phase or amplitude of the training signal received in the absence of the object 402. As a result, the wireless channel 440 may differ from the wireless channel 430 previously measured by the RX device 420. In some implementations, the RX device 420 may transmit a CSI report 446, which includes the CSI associated with the wireless channel 440, back to the TX device 410.

[0060] The TX device 410 can perform RF sensing operations based on changes or differences between wireless channels 430 and 440. Exemplary suitable RF sensing operations may include object detection, motion detection, motion classification (e.g., walking, falling, or gestures), object tracking (e.g., direction, range, or location of movement), and vital sign monitoring (e.g., breathing). The TX device 410 can detect such changes between wireless channels 430 and 440 by comparing the CSI associated with wireless channel 440 (carried in channel report 446) with the CSI associated with wireless channel 430 (carried in channel report 436). Assuming that the TX device 410 and the RX device 420 remain relatively stationary during channel detection operations (e.g., from Figure 4A to Figure 4B), the difference between wireless channels 430 and 440 can be attributed to the presence or movement of a new object 402.

[0061] Figure 5 illustrates an exemplary CSI matrix 500. Referring, for example, to Figures 4A and 4B, CSI matrix 500 can be an instance of the CSI associated with either wireless channel 430 or 440, acquired by RX device 420. As shown in Figure 5, CSI matrix 500 is a three-dimensional matrix of CFR values ​​501 spanning a number (M) of transmit (TX) antennas used for transmitting training signals, a number (N) of receive (RX) antennas used for receiving training signals, and a number (K) of tones spanning the bandwidth of the wireless channel. Each of the CFR values ​​501 can be a complex number having in-phase and quadrature components or amplitude and phase components. More specifically, CFR values ​​501i,j,q represent the channel frequency response associated with the i-th TX antenna (1≤i≤M), the j-th RX antenna (1≤j≤N), and the q-th tone (1≤q≤K). Therefore, the size of CSI matrix 500 depends on the bandwidth of the wireless channel and the number of antennas used for transmitting and receiving training signals.

[0062] In some embodiments, each CSI report can be carried in a management frame (e.g., an action frame). Therefore, any CSI larger than the payload of a management frame (>11,454 bytes) must be transmitted across multiple management frames. Various aspects of this application recognize that some RF sensing applications may not require complete or comprehensive CSI reports. In other words, the TX device or initiator may not need to receive all CFR values ​​5011,1,1–501M,N,K of the CSI matrix 500 to perform one or more RF sensing operations. For example, the TX device or initiator can detect the presence or movement of an object in its surrounding environment based on changes in the wireless channel. For any combination of TX and RX antennas, such changes can be detected in any tone (or subset of tone) across the wireless channel bandwidth. Furthermore, such changes can be detected in any component of the channel frequency response, such as the in-phase, quadrature, amplitude, or phase components of each CFR value 501.

[0063] In some configurations, the RX device or responder can classify CFR values ​​5011,1,1–501M,N,K into multiple subsets for transmission in multiple CFR reports. More specifically, CFR values ​​501 can be classified in such a way that the TX device or initiator responds to each CFR report to perform one or more RF sensing operations. In some implementations, CFR values ​​501 can be classified according to K tones to classify CFR values ​​501 associated with the same tone subset into the same CFR value subset. In some other implementations, CFR values ​​501 can be classified according to M TX antennas to classify CFR values ​​501 associated with the same TX antenna subset into the same CFR value subset. In some implementations, CFR values ​​501 can be classified according to N RX antennas to classify CFR values ​​501 associated with the same RX antenna subset into the same CFR value subset. Furthermore, in some embodiments, portions of each CFR value 501 may be classified into different subsets such that at least one subset includes one or more I components or amplitude components of the CFR value 501, and another subset includes one or more Q components or phase components of the CFR value 501.

[0064] FIG6A illustrates an exemplary CSI matrix 600, which includes a set of CFR values ​​categorized into multiple subsets (groups 1-4). In some embodiments, CSI matrix 600 may be an instance of CSI matrix 500 of FIG5. Referring, for example, to FIG4A and FIG4B, in response to receiving probe packets from TX device 410 via a wireless channel spanning K tones, RX device 420 may capture or acquire CSI matrix 600. More specifically, probe packets may be transmitted using the four TX antennas T1-T4 of TX device 410 and received using the four RX antennas R1-R4 of RX device 420. Thus, each CFR value of CSI matrix 600 indicates the corresponding channel frequency response associated with one of the TX antennas T1-T4, one of the RX antennas R1-R4, and one of the K tones based on its position in the matrix. In some embodiments, each CFR value may be assigned to one of groups 1-4 based on its associated tone.

[0065] In the example of Figure 6A, each of groups 1-4 can include any CFR value across the range of TX antennas T1-T4 and RX antennas R1-R4 and associated with the corresponding tone subset. More specifically, each tone subset is a subtracted subset of K tones with a corresponding offset or starting tone index (ranging from 1 to 4 in the example of Figure 6A). For example, group 1 includes all CFR values ​​associated with the first tone and every fourth tone thereafter, preceding and including the (K-3)th tone; group 2 includes all CFR values ​​associated with the second tone and every fourth tone thereafter, preceding and including the (K-2)th tone; group 3 includes all CFR values ​​associated with the third tone and every fourth tone thereafter, preceding and including the (K-1)th tone; and group 4 includes all CFR values ​​associated with the fourth tone and every fourth tone thereafter, preceding and including the Kth tone. More generally, each subset of CFR values ​​can be identified by a tuple (extraction factor, starting tone index). Therefore, groups 1-4 collectively represent the complete set of CFR values ​​associated with CSI matrix 600. In the example of Figure 6A, each tone subset has an extraction factor equal to 4. However, in some other implementations, any decimation factor can be used to decimate the K tones.

[0066] Figure 6B illustrates an exemplary CSI matrix 610, which includes a set of CFR values ​​categorized into multiple subsets (groups 1-4). In some embodiments, CSI matrix 610 may be an instance of CSI matrix 500 of Figure 5. Referring, for example, to Figures 4A and 4B, in response to receiving probe packets from TX device 410 via a wireless channel spanning K tones, RX device 420 may capture or acquire CSI matrix 610. More specifically, probe packets may be transmitted using the four TX antennas T1-T4 of TX device 410 and received using the four RX antennas R1-R4 of RX device 420. Thus, each CFR value of CSI matrix 610 indicates the corresponding channel frequency response associated with one of the TX antennas T1-T4, one of the RX antennas R1-R4, and one of the K tones based on its position in the matrix. In some embodiments, each CFR value may be assigned to one of groups 1-4 based on its associated tone.

[0067] In the example of Figure 6B, each of groups 1-4 may include any CFR value associated with the range of TX antennas T1-T4 and RX antennas R1-R4 and the corresponding tone subset. More specifically, each tone subset spans the corresponding subband within the wireless channel bandwidth. For example, group 1 includes all CFR values ​​associated with consecutive tones from 1 to x, group 2 includes all CFR values ​​associated with consecutive tones from x+1 to y, group 3 includes all CFR values ​​associated with consecutive tones from y+1 to z, and group 4 includes all CFR values ​​associated with consecutive tones from z+1 to K. Each consecutive tone subset may span the corresponding portion of the bandwidth spanned by tones 1–K. For example, assuming tones 1–K span an 80 MHz bandwidth, each consecutive tone subset may span the corresponding 20 MHz portion of the 80 MHz bandwidth. More generally, each subset of CFR values ​​can be identified via a tuple (BW, BW index), where BW represents the bandwidth of the currently operating channel and the BW index represents the position of the corresponding subband within the channel bandwidth. In some implementations, the BW index may indicate the relative position associated with the currently operating channel (e.g., the first, second, third, or fourth 20 MHz sub-channel of the current 80 MHz channel). In some other implementations, the BW index may be a channel index defined by an existing version of the IEEE 802.11 standard (e.g., a channelization definition). Thus, groups 1-4 collectively represent the complete set of CFR values ​​associated with CSI matrix 610. In the example of Figure 6A, each tone subset spans one-quarter of the overall bandwidth. However, in some other implementations, each tone subset may span any portion of the overall bandwidth.

[0068] Figure 6C illustrates an exemplary CSI matrix 620, which includes a set of CFR values ​​categorized into multiple subsets (groups 1-4). In some embodiments, CSI matrix 620 may be an instance of CSI matrix 500 of Figure 5. Referring, for example, to Figures 4A and 4B, in response to receiving probe packets from TX device 410 via a wireless channel spanning K tones, RX device 420 may capture or acquire CSI matrix 620. More specifically, probe packets may be transmitted using the four TX antennas T1-T4 of TX device 410 and received using the four RX antennas R1-R4 of RX device 420. Thus, each CFR value of CSI matrix 620 indicates the corresponding channel frequency response associated with one of the TX antennas T1-T4, one of the RX antennas R1-R4, and one of the K tones based on its position in the matrix. In some embodiments, each CFR value may be assigned to one of groups 1-4 based on its associated TX antenna.

[0069] In the example of FIG. 6C, each of groups 1-4 may include any CFR value associated with the range of RX antennas R1-R4 and K tones and the corresponding TX antenna subset. For example, group 1 includes all CFR values ​​associated with the first TX antenna T1, group 2 includes all CFR values ​​associated with the second TX antenna T2, group 3 includes all CFR values ​​associated with the third TX antenna T3, and group 4 includes all CFR values ​​associated with the fourth TX antenna T4. Thus, groups 1-4 collectively represent the complete set of CFR values ​​associated with CSI matrix 620. In the example of FIG. 6C, each TX antenna subset includes exactly one TX antenna. However, in some other embodiments, any number of TX antennas may be included in the subset. For example, in some embodiments, each TX antenna subset may include two TX antennas. In this embodiment, the number of CFR value subsets may be halved compared to the number of CFR value subsets shown in FIG. 6C.

[0070] FIG6D illustrates an exemplary CSI matrix 630, which includes a set of CFR values ​​categorized into multiple subsets (groups 1-4). In some embodiments, CSI matrix 630 may be an instance of CSI matrix 500 of FIG5. Referring, for example, to FIG4A and FIG4B, in response to receiving probe packets from TX device 410 via a wireless channel spanning K tones, RX device 420 may capture or acquire CSI matrix 630. More specifically, probe packets may be transmitted using the four TX antennas T1-T4 of TX device 410 and received using the four RX antennas R1-R4 of RX device 420. Thus, each CFR value of CSI matrix 630 indicates the corresponding channel frequency response associated with one of the TX antennas T1-T4, one of the RX antennas R1-R4, and one of the K tones based on its position in the matrix. In some embodiments, each CFR value may be assigned to one of groups 1-4 based on its associated RX antenna.

[0071] In the example of FIG6D, each of groups 1-4 may include any CFR value associated with the range of TX antennas T1-T4 and the range of K tones, and associated with the corresponding subset of RX antennas. For example, group 1 includes all CFR values ​​associated with the first RX antenna R1, group 2 includes all CFR values ​​associated with the second RX antenna R2, group 3 includes all CFR values ​​associated with the third RX antenna R3, and group 4 includes all CFR values ​​associated with the fourth RX antenna R4. Thus, groups 1-4 collectively represent the complete set of CFR values ​​associated with CSI matrix 630. In the example of FIG6D, each subset of RX antennas includes exactly one RX antenna. However, in some other embodiments, any number of RX antennas may be included in the subset. For example, in some embodiments, each subset of RX antennas may include two RX antennas. In this embodiment, the number of CFR value subsets may be halved compared to the number of CFR value subsets shown in FIG6D.

[0072] Figure 6E illustrates an exemplary CSI matrix 640, which includes a set of CFR values ​​categorized into multiple subsets (groups 1 and 2). In some embodiments, CSI matrix 640 may be an instance of CSI matrix 500 of Figure 5. Referring, for example, to Figures 4A and 4B, in response to receiving probe packets from TX device 410 via a wireless channel spanning K tones, RX device 420 may capture or acquire CSI matrix 640. More specifically, probe packets may be transmitted using the four TX antennas T1-T4 of TX device 410 and received using the four RX antennas R1-R4 of RX device 420. Thus, each CFR value of CSI matrix 640 indicates the corresponding channel frequency response associated with one of the TX antennas T1-T4, one of the RX antennas R1-R4, and one of the K tones based on its position in the matrix. In some embodiments, portions of each CFR value may be assigned to one of group 1 or 2, so that different portions of the same CFR value are assigned to different groups.

[0073] In the example of FIG6E, each of groups 1 and 2 may include a corresponding portion of each CFR value across the range of TX antenna T1–T4, the range of RX antenna R1–R4, and the range of K tones. For example, group 1 includes a first portion of each CFR value of CSI matrix 640, and group 2 includes a second portion of each CFR value of CSI matrix 640. In some embodiments, the first portion may represent the in-phase (I) component of each CFR value, and the second portion may represent the quadrature (Q) component of each CFR value. In some other embodiments, the first portion may represent the amplitude component of each CFR value, and the second portion may represent the phase component of each CFR value. Thus, groups 1 and 2 together represent the complete set of CFR values ​​associated with CSI matrix 640. In the example of FIG6E, all CFR values ​​are classified into two subsets. However, in some other implementations, the granularity of the classification can be finer. For example, in some embodiments, group 1 may include only the I component or amplitude component of the subset of CFR values, and group 2 may include the Q component or phase component of that subset of CFR values.

[0074] As previously mentioned, any subset of CFR values ​​shown in Figures 6A-6E can be used to perform one or more RF sensing operations. Furthermore, each subset can be carried in the payload of a single management frame. Therefore, in some embodiments, the RX device can transmit a single CSI report carrying one or more subsets of CFR values ​​in response to receiving a probe packet from the TX device. In some other embodiments, the RX device can transmit multiple CSI reports, each carrying one or more subsets of CFR values, so that the TX device receives the complete set of CFR values ​​in response to the probe packet. Furthermore, in some embodiments, one or more classification techniques described with reference to Figures 6A-6E can be combined to further reduce the size of each CSI report. For example, a given CSI report may include only the CFR values ​​associated with every fourth tone across a 20 MHz subband between a given RX antenna and a given TX antenna.

[0075] FIG7 illustrates a sequence diagram 700 of exemplary message exchange between devices participating in a channel probe operation. In the example of FIG7, a channel probe operation is performed between a TX device 710 (acting as the initiator) and an RX device 720 (acting as the responder). In some embodiments, the TX device 710 may be an instance of AP 110 of FIG1 or AP 300 of FIG3. In some other embodiments, the TX device 710 may be an instance of either STA 120 of FIG1 or STA 200 of FIG2. In some embodiments, the RX device 720 may be an instance of either AP 110 of FIG1 or AP 300 of FIG3. In some other embodiments, the RX device 720 may be an instance of either STA 120 of FIG1 or STA 200 of FIG2.

[0076] TX device 710 initiates a channel probing operation by transmitting a probe announcement to RX device 720, followed by a probe packet. In some embodiments, the probe announcement may be an NDP announcement frame (NDPA), and the probe packet may be an NDP. In some embodiments, the NDPA may indicate one or more subsets of CFR values ​​to be reported by RX device 720 (in one or more CSI reports). In some other embodiments, the NDPA may indicate how to classify CFR values ​​among multiple CSI reports. The probe packet includes a known pattern or sequence (transmitted in one or more LTFs) of training signals that can be used to acquire CSI. TX device 710 may transmit the probe packet over a number (K) tones across the bandwidth of the wireless channel 730 between TX device 710 and RX device 720 via a number (M) of TX antennas. RX device 720 receives the probe packet via a number (N) of RX antennas and acquires CSI based on the received training signals (e.g., as described with reference to Figures 4A and 4B). CSI can be modeled as an MxNxK matrix of CFR values ​​(e.g., CSI matrix 500 in Figure 5), where each CFR value indicates the channel frequency response associated with the corresponding TX antenna among the M TX antennas, the corresponding RX antenna among the N RX antennas, and the corresponding tone among the K tones.

[0077] In some embodiments, the RX device 720 can classify CFR values ​​into multiple subsets (groups 1-4), where each subset of CFR values ​​can be used for one or more RF sensing operations and is small enough to be transmitted in a single management frame. In some implementations, CFR values ​​can be classified according to K tones so that CFR values ​​associated with the same tone subset are classified into the same CFR value subset (e.g., as described in Figures 6A and 6B). In some other implementations, CFR values ​​can be classified according to M TX antennas so that CFR values ​​associated with the same TX antenna subset are classified into the same CFR value subset (e.g., as described in Figure 6C). In some implementations, CFR values ​​can be classified according to N RX antennas so that CFR values ​​associated with the same RX antenna subset are classified into the same CFR value subset (e.g., as described in Figure 6D). Furthermore, in some implementations, at least one subset may include only the in-phase or amplitude components of one or more CFR values, while another subset may include only the quadrature or phase components of the one or more CFR values ​​(e.g., as described with reference to FIG6E).

[0078] The RX device 720 further transmits one or more CSI report frames back to the TX device 710. In some embodiments, each CSI report may include a corresponding subset of CFR values. As shown in FIG7, the RX device 720 transmits a CSI report carrying CFR values ​​in group 1, followed by a CSI report carrying CFR values ​​in group 2, followed by a CSI report carrying CFR values ​​in group 3, and finally a CSI report carrying CFR values ​​in group 4. The TX device 710 may perform one or more RF sensing operations after receiving any CSI report. For example, after receiving a first CSI report from the RX device 720, the TX device 710 may perform at least a portion of the RF sensing operation based on the CFR values ​​in group 1. In some embodiments, each CSI report may be transmitted in response to a corresponding trigger frame (not shown for simplicity) received from the TX device 710. In some other embodiments, such CSI reports may be transmitted in response to a single trigger frame (not shown for simplicity) received from the TX device 710. For example, each CSI report can be transmitted as a corresponding MPDU of the Converged Media Access Control (MAC) Protocol Data Unit (A-MPDU). In response to each subsequent CSI report, the TX device 710 can subsequently update the RF sensing operation or can perform a new RF sensing operation.

[0079] In the example of FIG. 7, RX device 720 transmits four CSI reports carrying CFR values ​​associated with groups 1-4. In some embodiments, groups 1-4 may collectively represent the complete set of CFR values ​​associated with radio channel 730. In some other embodiments, groups 1-4 may include only a partial set of CFR values ​​associated with radio channel 730. Furthermore, in some embodiments, RX device 720 may transmit fewer or more CSI reports than shown in FIG. 7. In some embodiments, TX device 710 and RX device 720 may negotiate the number of CSI reports to be transmitted by RX device 720 before initiating channel probe operation. In this embodiment, TX device 710 and RX device 720 may also negotiate to include a subset of CFR values ​​in each CSI report.

[0080] In some other embodiments, RX device 720 may determine the number of CSI reports to be transmitted to TX device 710 and the subset of CFR values ​​to be included in each CSI report. In this embodiment, RX device 720 may provide classification information in each CSI report, which identifies the subset of CFR values ​​provided in the CSI report. For example, referring to FIG6A, the classification information may indicate the decimation factor and corresponding offset associated with each reported tone subset. For example, referring to FIG6B, the classification information may indicate the corresponding sub-band associated with each reported tone subset. For example, referring to FIG6C, the classification information may indicate the corresponding TX antenna associated with each reported TX antenna subset. For example, referring to FIG6D, the classification information may indicate the corresponding RX antenna associated with each reported RX antenna subset. For example, referring to FIG6E, the classification information may indicate which component of each CFR value is included in each reported subset.

[0081] In some other embodiments, TX device 710 may determine the number of CSI reports to be transmitted by RX device 720 and the subset of CFR values ​​to be included in each CSI report. In this embodiment, TX device 710 may provide a CSI request in a trigger frame or NDPA indicating the subset of CFR values ​​to be included in each CSI report. For example, referring to FIG6A, the CSI request may indicate the decimation factor and corresponding offset associated with each requested tone subset. For example, referring to FIG6B, the CSI request may indicate the corresponding subband associated with each requested tone subset. For example, referring to FIG6C, the CSI request may indicate the corresponding TX antenna associated with each requested TX antenna subset. For example, referring to FIG6D, the CSI request may indicate the corresponding RX antenna associated with each requested RX antenna subset. For example, referring to FIG6E, the CSI request may indicate which component of each CFR value will be included in each requested subset.

[0082] In the example of Figure 7, the RX device 720 transmits each CSI report in response to the same probe packet transmitted by the TX device 710. In other words, the CFR values ​​in each group in groups 1–4 originate from the same CSI capture. Various aspects of this application recognize that a wireless channel may undergo little (if any) change over a short period of time. Therefore, when multiple probe packets are transmitted over such a short period of time, the CSI obtained from each probe packet may be substantially similar. Therefore, in some embodiments, the RX device may acquire different subsets of CFR values ​​in response to different probe packets transmitted by the TX device, wherein each subset of CFR values ​​can be considered as if it came from the same CSI capture.

[0083] FIG8 illustrates a sequence diagram 800 of exemplary message exchange between devices participating in a channel probe operation. In the example of FIG8, a channel probe operation is performed between a TX device 810 (acting as the initiator) and an RX device 820 (acting as the responder). In some embodiments, the TX device 810 may be an instance of AP 110 of FIG1 or AP 300 of FIG3. In some other embodiments, the TX device 810 may be an instance of either STA 120 of FIG1 or STA 200 of FIG2. In some embodiments, the RX device 820 may be an instance of either AP 110 of FIG1 or AP 300 of FIG3. In some other embodiments, the RX device 820 may be an instance of either STA 120 of FIG1 or STA 200 of FIG2.

[0084] The TX device 810 initiates a channel probing operation by transmitting a probe announcement (NDPA) to the RX device 820, followed by a first probe packet (NDP1). In the example of Figure 8, the TX device 810 transmits a series of NDPAs and NDPs within a short time period. More specifically, the TX device 810 transmits three additional probe announcements shortly after transmitting the first probe packet NDP1, each followed by a corresponding probe packet (NDP2–NDP4). In some embodiments, the TX device 810 may transmit each probe packet NDP1–NDP4 over a number (K) tones across the bandwidth of the wireless channel 830 between the TX device 810 and the RX device 820 via a number (M) of TX antennas. The RX device 820 receives each probe packet NDP1–NDP4 via a number (N) RX antennas and acquires CSIs (CSI_1–CSI_4) based on the training signals received in the probe packets NDP1–NDP4 (e.g., as described with reference to Figures 4A and 4B). Therefore, each CSI can be modeled as an MxNxK matrix of the corresponding CFR value (e.g., CSI matrix 500 in Figure 5).

[0085] For each CSI, the RX device 820 can classify the associated CFR values ​​into multiple subsets (groups 1-4), where each subset of CFR values ​​can be used for one or more RF sensing operations and is small enough to be transmitted in a single management frame. In some embodiments, CFR values ​​can be classified according to K tones so that CFR values ​​associated with the same tone subset are classified into the same CFR value subset (e.g., as described in Figures 6A and 6B). In some other embodiments, CFR values ​​can be classified according to M TX antennas so that CFR values ​​associated with the same TX antenna subset are classified into the same CFR value subset (e.g., as described in Figure 6C). In some embodiments, CFR values ​​can be classified according to N RX antennas so that CFR values ​​associated with the same RX antenna subset are classified into the same CFR value subset (e.g., as described in Figure 6D). Furthermore, in some implementations, at least one subset may include only the in-phase or amplitude components of one or more CFR values, while another subset may include only the quadrature or phase components of those one or more CFR values ​​(e.g., as described with reference to FIG6E).

[0086] For each probe packet NDP1–NDP4, RX device 820 transmits the corresponding CSI report frame back to TX device 810. In some embodiments, each CSI report may include a subset of the corresponding CFR values ​​from the corresponding CSI. As shown in FIG8, RX device 820 transmits a CSI report carrying the CFR values ​​in group 1 of CSI_1, followed by a CSI report carrying the CFR values ​​in group 2 of CSI_2, followed by a CSI report carrying the CFR values ​​in group 3 of CSI_3, and followed by a CSI report carrying the CFR values ​​in group 4 of CSI_4. In some embodiments, each CSI report may be transmitted in response to a corresponding trigger frame (not shown for simplicity) received from TX device 810. In some other embodiments, such CSI reports may be transmitted in response to a single trigger frame (not shown for simplicity) received from TX device 810. For example, each CSI report may be transmitted as a corresponding MPDU of an A-MPDU. TX device 810 can perform one or more RF sensing operations after receiving any CSI report. For example, after receiving the first CSI report from RX device 820, TX device 810 can perform at least a portion of the RF sensing operation based on the CFR value in group 1. In response to each subsequent CSI report, TX device 810 can subsequently update the RF sensing operation or perform a new RF sensing operation.

[0087] In the example of FIG8, RX device 820 transmits four CSI reports, each carrying CFR values ​​associated with groups 1–4 of CSI_1–CSI_4. In some embodiments, groups 1–4 may collectively represent the complete set of CFR values ​​associated with radio channel 830. In some other embodiments, groups 1–4 may include only a partial set of CFR values ​​associated with radio channel 830. Furthermore, in some embodiments, RX device 820 may transmit fewer or more CSI reports than shown in FIG8. In some embodiments, TX device 810 and RX device 820 may negotiate the number of CSI reports to be transmitted by RX device 820 before initiating channel probe operation. In this embodiment, TX device 810 and RX device 820 may also negotiate a subset of CFR values ​​to be included in each CSI report.

[0088] In some other embodiments, the RX device 820 may determine the number of CSI reports to be transmitted to the TX device 810 and the subset of CFR values ​​to be included in each CSI report. In this embodiment, the RX device 820 may provide classification information in each CSI report, which identifies the subset of CFR values ​​provided in that CSI report (e.g., referring to FIG. 7). In some other embodiments, the TX device 810 may determine the number of CSI reports to be transmitted by the RX device 820 and the subset of CFR values ​​to be included in each CSI report. In this embodiment, the TX device 810 may provide a CSI request in a trigger frame or in each NDPA, indicating the subset of CFR values ​​to be included in each CSI report (e.g., referring to FIG. 7).

[0089] In the examples of Figures 7 and 8, each CSI report is carried in a corresponding management frame (e.g., an action frame). Various embodiments of this content recognize that by reducing the size of each CSI report, multiple CSI reports can be carried in the same management frame. In some embodiments, each CSI report may include CSIs for different radio channels. In some implementations, the RX device may acquire each CSI in response to a corresponding probe packet transmitted by the same TX device. In some other implementations, the RX device may acquire each CSI in response to a probe packet transmitted by a corresponding TX device. By including multiple CSI reports in a single management frame, various embodiments of this content can reduce the management burden associated with reporting CSIs. For example, the TX device or initiator may perform multiple RF sensing operations (in different radio channels) in response to a single CSI report.

[0090] Figure 9 illustrates a sequence diagram 900 of an exemplary message exchange between devices participating in a channel probe operation. In the example of Figure 9, a channel probe operation is performed between a TX device 910 (acting as the initiator) and an RX device 920 (acting as the responder). In some embodiments, the TX device 910 may be an instance of AP 110 of Figure 1 or AP 300 of Figure 3. In some other embodiments, the TX device 910 may be an instance of either STA 120 of Figure 1 or STA 200 of Figure 2. In some embodiments, the RX device 920 may be an instance of either AP 110 of Figure 1 or AP 300 of Figure 3. In some other embodiments, the RX device 920 may be an instance of either STA 120 of Figure 1 or STA 200 of Figure 2.

[0091] TX device 910 initiates channel probing operation by transmitting a probe announcement (NDPA) to RX device 920, followed by transmitting a first probe packet (NDP1). For example, TX device 910 may transmit NDP1 over a number (K) tones across the bandwidth of a first wireless channel 930 between TX device 910 and RX device 920 via a number (M) of TX antennas. RX device 920 receives NDP1 via a number (N) of RX antennas and acquires a first CSI (CSI_1) based on the training signal received in NDP1 (e.g., as described with reference to Figures 4A and 4B). The first CSI may be modeled as an MxNxK matrix of CFR values ​​(e.g., CSI matrix 500 of Figure 5), where each CFR value indicates the channel frequency response associated with a corresponding TX antenna among the M TX antennas, a corresponding RX antenna among the N RX antennas, and a corresponding tone among the K tones.

[0092] In the example of FIG9, TX device 910 then transmits another probe announcement to RX device 920, followed by a second probe packet (NDP2). For example, TX device 910 may transmit NDP2 over a number (Z) tones across the bandwidth of a second wireless channel 940 between TX device 910 and RX device 920 via a number (X) of TX antennas. RX device 920 receives NDP2 via a number (Y) of RX antennas and acquires a second CSI (CSI_2) based on the training signal received in NDP2 (e.g., as described with reference to FIG4A and FIG4B). The second CSI may be modeled as an XxYxZ matrix of CFR values ​​(e.g., CSI matrix 500 of FIG5), where each CFR value indicates the channel frequency response associated with a corresponding TX antenna among the X TX antennas, a corresponding RX antenna among the Y RX antennas, and a corresponding tone among the Z tones. In some cases, at least one of M, N, or K may be different from X, Y, or Z, respectively. Therefore, CSI_1 can be different from CSI_2.

[0093] In some embodiments, the TX device 910 may transmit a trigger frame to the RX device 920, requesting feedback associated with radio channels 930 and 940. The RX device 920 may respond to the trigger frame (or NDP1 and NDP2) by transmitting a CSI report frame back to the TX device 910. In some cases, the CSI report frame may carry feedback associated with CSI_1 and CSI_2. In some embodiments, the feedback may include the complete set of CFR values ​​for each of CSI_1 and CSI_2. For example, the feedback may include raw or uncompressed CFR values. Alternatively, the size of the feedback may be reduced by compression, quantization, or decimation (e.g., referring to FIG. 6A). In some other embodiments, the feedback may include only a subset of the CFR values ​​for at least one of CSI_1 or CSI_2 (e.g., referring to FIG. 7 and FIG. 8). Therefore, the TX device 910 can perform one or more RF sensing operations in each of the wireless channels 930 and 940, respectively, based on feedback associated with CSI_1 and CSI_2.

[0094] In the example of FIG9, RX device 920 transmits a single CSI report frame carrying feedback or CSI associated with two radio channels 930 and 940. In some embodiments, the CSI report frame may carry feedback or CSI for more than two radio channels. In some other embodiments, the RX device may transmit multiple CSI report frames carrying feedback or CSI for two or more radio channels, wherein each CSI report frame carries a portion of the feedback or CSI for each of the two or more radio channels. In some cases, TX device 910 and RX device 920 may negotiate the number of CSI reports to be transmitted by RX device 920 before initiating channel probing operation. Therefore, TX device 910 and RX device 920 may also negotiate the number of radio channels represented in each CSI report frame and the size of the feedback or CSI associated with each radio channel.

[0095] FIG10 illustrates a sequence diagram 1000 of exemplary message exchange between devices participating in a channel probe operation. In the example of FIG10, a channel probe operation is performed between an initiating device 1040, a plurality of TX devices 1010 and 1030, and an RX device 1020 (acting as a responder). In some embodiments, at least one of the TX devices 1010 or 1030 may be an instance of AP 110 of FIG1 or AP 300 of FIG3. In some other embodiments, at least one of the TX devices 1010 or 1030 may be an instance of STA 120 of FIG1 or STA 200 of FIG2. In some embodiments, RX device 1020 may be an instance of AP 110 of FIG1 or AP 300 of FIG3. In some other embodiments, RX device 1020 may be an instance of STA 120 of FIG1 or STA 200 of FIG2.

[0096] The first TX device 1010 initiates a channel probing operation (representing initiator 1040) by transmitting a probe announcement (NDPA) to the RX device 1020, followed by transmitting a first probe packet (NDP1). For example, the first TX device 1010 may transmit NDP1 over a number (K) tones across the bandwidth of a first wireless channel 1050 between the first TX device 1010 and the RX device 1020 via a number (M) of TX antennas. The RX device 1020 receives NDP1 via a number (N) of RX antennas and acquires a first CSI (CSI_1) based on the training signal received in NDP1 (e.g., as described with reference to Figures 4A and 4B). The first CSI may be modeled as an MxNxK matrix of CFR values ​​(e.g., CSI matrix 500 of Figure 5), where each CFR value indicates the channel frequency response associated with a corresponding TX antenna among the M TX antennas, a corresponding RX antenna among the N RX antennas, and a corresponding tone among the K tones.

[0097] In the example of FIG10, the second TX device 1030 then transmits a probe announcement to the RX device 1020, followed by a second probe packet (NDP2). For example, the second TX device 1030 may transmit NDP2 over a number (Z) tones across the bandwidth of the second wireless channel 1060 between the second TX device 1030 and the RX device 1020 via a number (X) TX antennas. The RX device 1020 receives NDP2 via a number (Y) RX antennas and acquires a second CSI (CSI_2) based on the training signal received in the second probe packet (e.g., as described with reference to FIG4A and FIG4B). The second CSI may be modeled as an XxYxZ matrix of CFR values ​​(e.g., CSI matrix 500 of FIG5), where each CFR value indicates the channel frequency response associated with the corresponding TX antenna among the X TX antennas, the corresponding RX antenna among the Y RX antennas, and the corresponding tone among the Z tones. In some samples, at least one of M, N, or K may be different from X, Y, or Z, respectively. Therefore, CSI_1 may be different from CSI_2.

[0098] In some embodiments, the initiator 1040 may transmit a trigger frame to the RX device 1020 requesting feedback associated with wireless channels 1050 and 1060. The RX device 1020 may respond to the trigger frame by transmitting a CSI report frame back to the initiator 1040. In some cases, the CSI report frame may carry feedback associated with CSI_1 and CSI_2. In some embodiments, the feedback may include the complete set of CFR values ​​for each of CSI_1 and CSI_2. For example, the feedback may include raw or uncompressed CFR values. Alternatively, the size of the feedback may be reduced by compression, quantization, or extraction (e.g., referring to FIG. 6A). In some other embodiments, the feedback may include only a subset of CFR values ​​for at least one of CSI_1 or CSI_2 (e.g., referring to FIG. 7 and FIG. 8). Therefore, the initiator 1040 can perform one or more RF sensing operations in each of the wireless channels 1050 and 1060, respectively, based on feedback associated with CSI_1 and CSI_2.

[0099] In the example of FIG. 10, RX device 1020 transmits a single CSI report frame carrying feedback or CSI associated with two radio channels 1050 and 1060. In some embodiments, the CSI report frame may carry feedback or CSI for more than two radio channels. In some other embodiments, the RX device may transmit multiple CSI report frames carrying feedback or CSI for two or more radio channels, wherein each CSI report frame carries a portion of the feedback or CSI for each of the two or more radio channels. In some cases, initiator 1040 and RX device 1020 may negotiate the number of CSI reports to be transmitted by RX device 1020 before initiating channel probing operation. Therefore, initiator 1040 and RX device 1020 may also negotiate the number of radio channels represented in each CSI report frame and the size of the feedback associated with each radio channel.

[0100] Each CSI report frame may include one or more report fields configured to carry feedback or CSI (including any subset of CFR values) for the corresponding radio channel. In some embodiments, each CSI report frame may also include one or more control fields configured to carry relay data associated with the feedback or CSI carried in the one or more report fields. Various embodiments of this content recognize that the captured CSI depends on the transmission parameters of the TX device, the reception parameters of the RX device, and the characteristics of the environment. In other words, changing any transmission or reception parameters between channel probe events may result in a change in CSI not caused by changes in the environment. In some embodiments, relay data may indicate one or more attributes or characteristics of the transmission or reception of probe packets associated with each CSI capture by the TX device, RX device, or the probe packet. Examples of relay data that can be included in the control fields of a CSI report frame are summarized in Table 1 below. Table 1 type describe Supplier ID Identify the supplier associated with the TX device or initiator, or indicate the CFR format. MAC address Indicates the MAC address of the RX device or the responder. Capture state Indicates whether CSI has been successfully captured or acquired. Capture bandwidth Indicates the bandwidth of the wireless channel or the received probe packets. aisle Indicates the main 20 MHz sub-channel of the wireless channel Frequency band center frequency 1 The first center frequency indicating the bandwidth Frequency band center frequency 2 The second center frequency indicating the bandwidth cfreq / seg0 / seg1 A subset of CFR values ​​included in the identification report Preceding signal type Indicates the version of the PHY pre-signal used to probe the packet (e.g., conventional, high throughput (HT), very high throughput (VHT), high efficiency (HE), or very high throughput (EHT), etc.). NSS Indicates the number of spatial streams or TX antennas used to transmit probe packets. RSSI of each chain Received Signal Strength Indication (RSSI) for each RX antenna chain CFO Indicates the carrier frequency offset (CFO) at the RX device. AGC gain Indicates the gain measured at the RX device via hardware measurement and applied via automatic gain control (AGC). RX chain mask Indicates the RX antenna associated with CSI acquisition. Timestamp Indicates the arrival time of the probe packet. length Indicates the size or length of the corresponding report field. Phase of each chain Indicates the phase change of the received signal that can be caused by the hardware of the RX device for each RX antenna chain. Extract Indicates the extraction factor associated with CSI extraction. RX speed information Indicates the decoding rate or modulation and decoding scheme (MCS) used to transmit probe packets. MU News Indicates whether the probe packet conforms to a single-user (SU) packet format or a multi-user (MU) packet format. Number of bits Indicates the number of bits used to quantize each CFR value.

[0101] Various aspects of this invention recognize that new signaling techniques may be needed to support the aggregation of multiple CSI reports within a single management frame. More specifically, such signaling may be needed to demarcate or distinguish feedback or CSI associated with a given radio channel from feedback or CSI associated with another radio channel within the same CSI report frame. In some embodiments, each pair of control fields and header fields associated with a given radio channel may be carried in a corresponding information element (IE) of the management frame, wherein the IE also includes a length field indicating the length of the IE. In some other embodiments, control fields and header fields may be sequentially located in the frame body of the management frame, wherein each control field immediately precedes the corresponding report field and carries length information indicating the length of the report field. Furthermore, in some embodiments, one or more separators may be added to the frame body of the management frame to demarcate control fields and report fields associated with different radio channels. In some formats, multiple CSI reports can be aggregated for transmission within a single packet or Entity Layer Aggregation Protocol (PLCP) Protocol Data Unit (PPDU). For example, each CSI report can be transmitted as a corresponding MPDU of an A-MPDU.

[0102] FIG11 illustrates exemplary CSI report frames 1100 for multiple captures. In some implementations, CSI report frame 1100 may be an instance of any CSI report frame of FIG7-FIG10. More specifically, CSI report frame 1100 may be a management frame configured to carry feedback or CSI associated with one or more radio channels.

[0103] The CSI report frame 1100 includes a MAC header 1110, a frame body 1120, and a frame check sequence (FCS) 1130. The MAC header 1110 includes a frame control field 1111, a duration field 1112, a receiver address (RA) field 1113, and a transmitter address (TA) field 1114. The frame body 1120 includes a plurality (n) of Interfaces (IEs) 1121, each IE 1121 having a corresponding length field 1122 indicating the length of the IE 1121. In some embodiments, feedback or CSI associated with each radio channel may be carried in the corresponding IE 1121. For example, as shown in FIG11, the IE 1121 may also include a control field 1123 and a report field 1124. The report field 1124 carries the CSI 1126 (or feedback) associated with the corresponding radio channel. In some implementations, CSI 1126 may include the complete set of CFR values ​​captured for the wireless channel. In other implementations, CSI 1126 may include only a subset of CFR values ​​captured for the wireless channel. Control field 1123 carries relay data 1125 associated with CSI 1126. Relay data 1125 may indicate one or more attributes or characteristics of the transmission or reception of TX devices, RX devices, or probe packets associated with CSI 1126. For example, relay data 1125 may include any information listed in Table 1.

[0104] In some embodiments, multiple IEs 1121 can be used to carry feedback or CSI associated with multiple wireless channels respectively. Therefore, the receiver (e.g., a TX device or initiator) of the CSI report frame 1100 can distinguish the CSI associated with each wireless channel based on the length field 1122 of each IE 1121. For example, the TX device or initiator can detect the control field 1123 and the report field 1124 based on the length field 1122, and can determine that the relay data 1125 in the control field 1123 and the CSI 1126 in the report field 1124 are associated with a specific wireless channel.

[0105] FIG12 illustrates exemplary CSI report frames 1200 for multiple captures. In some implementations, CSI report frame 1200 may be an instance of any CSI report frame of FIG7-FIG10. More specifically, CSI report frame 1200 may be a management frame configured to carry feedback or CSI associated with one or more radio channels.

[0106] The CSI report frame 1200 includes a MAC header 1210, a frame body 1220, and an FCS 1230. The MAC header 1210 includes frame control fields 1211, a duration field 1212, an RA field 1213, and a TA field 1214. The frame body 1220 includes several (n) control fields 1221 and report fields 1222. Each report field 1222 carries a CSI 1225 (or feedback) associated with the corresponding radio channel. In some embodiments, the CSI 1225 may include the complete set of CFR values ​​captured for the radio channel. In some other embodiments, the CSI 1225 may include only a subset of the CFR values ​​captured for the radio channel. Each control field 1221 immediately preceding the report field 1222 carries relay data 1224 associated with the CSI 1225 in the report field 1222. Relay data 1224 may indicate one or more attributes or characteristics of the transmission or reception of TX devices, RX devices, or probe packets associated with CSI 1225. For example, relay data 1224 may include any information listed in Table 1.

[0107] Unlike the CSI report frame 1100 of FIG11, the control field 1221 and the report field 1222 are not limited by IE. Therefore, in some configurations, each control field 1221 may also carry length information 1223 indicating the length of the subsequent report field 1222. In some implementations, multiple control fields 1221 and multiple report fields 1222 may be arranged sequentially in the frame body 1220. Therefore, the receiver (e.g., TX device or initiator) of the CSI report frame 1200 can distinguish the CSI associated with each radio channel based on the length information 1223 in each control field 1221. For example, the TX device or initiator can detect the report field 1222 based on the length information 1223 and can determine that the relay data 1224 in the control field 1221 and the CSI 1225 in the report field 1222 are associated with a specific radio channel.

[0108] FIG13 illustrates exemplary CSI report frames 1300 for multiple captures. In some implementations, CSI report frame 1300 may be an instance of any CSI report frame of FIG7-FIG10. More specifically, CSI report frame 1300 may be a management frame configured to carry feedback or CSI associated with one or more radio channels.

[0109] The CSI report frame 1300 includes a MAC header 1310, a frame body 1320, and an FCS 1330. The MAC header 1310 includes frame control fields 1311, a duration field 1312, an RA field 1313, and a TA field 1314. The frame body 1320 includes several (n) control fields 1321 and report fields 1322. Each report field 1322 carries a CSI 1324 (or feedback) associated with the corresponding radio channel. In some embodiments, the CSI 1324 may include the complete set of CFR values ​​captured for the radio channel. In some other embodiments, the CSI 1324 may include only a subset of the CFR values ​​captured for the radio channel. Each control field 1321 immediately preceding the report field 1322 carries relay data 1323 associated with the CSI 1324 in the report field 1322. Relay data 1323 may indicate one or more attributes or characteristics of the transmission or reception of TX devices, RX devices, or probe packets associated with CSI 1324. For example, relay data 1323 may include any information listed in Table 1.

[0110] Unlike the CSI report frame 1100 of FIG11, the control field 1221 and the report field 1222 are not limited by the IE. Therefore, in some configurations, one or more separators may be inserted between the control field 1221 and the report field 1222 associated with different radio channels. For example, each separator may include a known bit sequence. In some implementations, a start separator (SD) may be inserted immediately before each control field 1321. In some other implementations, an end separator (ED) may be inserted immediately after each report field 1322. In some implementations, a plurality of control fields 1321 and a plurality of report fields 1322 may be included in the frame body 1320. Therefore, the receiver (e.g., a TX device or initiator) of the CSI report frame 1300 may distinguish the CSI associated with each radio channel based on the separator (SD or ED). For example, the TX device or initiator can detect the control field 1321 and the report field 1322 based on the position of the separator, and can determine that the relay data 1323 in the control field 1321 and the CSI 1324 in the report field 1322 are associated with a specific wireless channel.

[0111] FIG14 illustrates an illustrative flowchart describing an exemplary wireless communication operation 1400. Exemplary operation 1400 can be performed by a wireless communication device, such as any of the RX devices 720, 820, 920 or 1020 as shown in FIG7-FIG10 respectively.

[0112] The wireless communication device receives one or more probe packets from the transmission device via a wireless channel (1402). The wireless communication device further acquires a CSI associated with the one or more probe packets, wherein the CSI includes a set of values ​​that are classified into multiple subsets according to a number (M) of transmitting antennas of the transmission device, a number (N) of receiving antennas of the wireless communication device, or a number (K) of tones across the bandwidth of the wireless channel, wherein each of the equivalent values ​​indicates a CFR associated with a corresponding transmitting antenna among the M transmitting antennas, a corresponding receiving antenna among the N receiving antennas, and a corresponding tone among the K tones (1404).

[0113] In some embodiments, each of the plurality of values ​​may be associated with the same probe packet in the one or more probe packets. In some other embodiments, the wireless communication device may acquire one or more first values ​​among the plurality of values ​​associated with a first probe packet in the one or more probe packets, wherein the one or more first values ​​are classified in a first subset of the plurality of subsets; and may acquire one or more second values ​​among the plurality of values ​​associated with a second probe packet in the one or more probe packets, wherein the one or more second values ​​are classified in a second subset of the plurality of subsets.

[0114] In some embodiments, the values ​​in the first subset of the plurality of subsets may indicate a CFR associated with one or more of the K tones, and the values ​​in the second subset of the plurality of subsets may indicate a CFR associated with one or more of the K tones that are different from the one or more first tones. For example, the one or more first tones may represent a first extracted subset of the K tones, and the one or more second tones may represent a second extracted subset of the K tones. Alternatively or additionally, the one or more first tones may span a first frequency band within the wireless channel bandwidth, and the one or more second tones may span a second frequency band within the wireless channel bandwidth.

[0115] In some embodiments, the values ​​in the first subset of the plurality of subsets may indicate the CFR associated with one or more of the M transmit antennas, and the values ​​in the second subset of the plurality of subsets may indicate the CFR associated with one or more of the M transmit antennas that are different from the one or more first transmit antennas. In other embodiments, the values ​​in the first subset of the plurality of subsets may indicate the CFR associated with one or more of the N receive antennas, and the values ​​in the second subset of the plurality of subsets may indicate the CFR associated with one or more of the N receive antennas that are different from the one or more first receive antennas.

[0116] In some embodiments, the values ​​in the first subset of the plurality of subsets may represent the in-phase (I) components of one or more CFRs, and the values ​​in the second subset of the plurality of subsets may represent the quadrature (Q) components of the one or more CFRs. In some other embodiments, the values ​​in the first subset of the plurality of subsets may represent the amplitude components of one or more CFRs, and the values ​​in the second subset of the plurality of subsets may represent the phase components of one or more CFRs.

[0117] The wireless communication device transmits one or more CSI report frames, each CSI report frame carrying a corresponding subset of values ​​from the plurality of subsets (1406). In some embodiments, each of the one or more CSI report frames may also carry classification information indicating the subset of values ​​carried in the CSI report frame. In some embodiments, the wireless communication device may also receive a CSI request indicating a corresponding subset of values ​​to be transmitted in each of the one or more CSI report frames.

[0118] Figure 15 illustrates an illustrative flowchart describing an exemplary wireless communication operation 1500. The exemplary operation 1500 can be performed by a wireless communication device, such as any of the RX devices 720, 820, 920 or 1020 as shown in Figures 7-10, respectively.

[0119] The wireless communication device receives a first probe packet via a first wireless channel (1502). The wireless communication device further acquires a first CSI associated with the first probe packet (1504). The wireless communication device receives a second probe packet via a second wireless channel (1506). The wireless communication device further acquires a second CSI associated with the second probe packet (1508). The wireless communication device transmits a CSI report frame (1510) including a first report field carrying the first CSI and a second report field carrying the second CSI.

[0120] In some embodiments, first and second probe packets can be received from the transmitting device. In this embodiment, the wireless communication device can further receive a trigger frame from the transmitting device, wherein a CSI report frame is transmitted to the transmitting device in response to the trigger frame. In some other embodiments, a first probe packet can be received from a first transmitting device, and a second probe packet can be received from a second transmitting device different from the first transmitting device. In this embodiment, the wireless communication device can further receive a trigger frame from an initiating device different from each of the first and second transmitting devices, wherein a CSI report frame is transmitted to the initiating device in response to the trigger frame.

[0121] In some embodiments, the first CSI report frame may further include a first control field carrying relay data associated with the first CSI, and may include a second control field carrying relay data associated with the second CSI. Exemplary relay data may include, but is not limited to: a vendor ID associated with a wireless communication device, a MAC address of a transmission device, an indication of whether a CSI was successfully acquired, a classification of CFR values, a preceding signal type associated with a received probe packet, RSSI per chain, CFO, AGC per chain, receive chain mask, a timestamp associated with a received probe packet, phase information per chain, a modulation type associated with a received probe packet, an indication of whether the received probe packet conforms to a multi-user format, and the number of bits associated with each CFR value.

[0122] In some embodiments, the CSI report frame may be a management frame with a frame body, the frame body including a first IE and a second IE, wherein the first IE includes a first control field and a first report field, and wherein the second IE includes a second control field and a second report field. In some other embodiments, the CSI report frame may be a management frame with a frame body including a first control field and a first report field immediately following it, and including a second control field and a second report field immediately following it, wherein the first control field further carries length information indicating the length of the first report field, and wherein the second control field further carries length information indicating the length of the second report field.

[0123] In some embodiments, the CSI report frame may be a management frame with a frame body including a first control field and a first report field immediately following it, and including a second control field and a second report field immediately following it, wherein the CSI report frame further includes a first separator immediately preceding the first control field and a second separator immediately preceding the second control field. In some other embodiments, the CSI report frame may be a management frame with a frame body including a first control field and a first report field immediately following it, and including a second control field and a second report field immediately following it, wherein the CSI report frame further includes a first separator immediately following the first report field and a second separator immediately following the second report field.

[0124] FIG16 illustrates a block diagram of an exemplary wireless communication device 1600. In some embodiments, the wireless communication device 1600 may be configured to perform process 1400 as described above with reference to FIG14. The wireless communication device 1600 may be an exemplary embodiment of any of the RX devices 720, 820, 920, or 1020 in FIGS. 7-10. More specifically, the wireless communication device 1600 may be a chip, SoC, chipset, package, or device including at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0125] The wireless communication device 1600 includes a receiving element 1610, a communication manager 1620, and a transmitting element 1630. The communication manager 1620 further includes a CFR classification element 1622. A portion of the CFR classification element 1622 may be implemented at least partially in hardware or firmware. In some embodiments, the CFR classification element 1622 is implemented at least partially as software stored in memory (e.g., memory 240 of FIG. 2 or memory 330 of FIG. 3). For example, a portion of the CFR classification element 1622 may be implemented as non-transitory instructions (or "code") executable by a processor (e.g., processor 220 of FIG. 2 or processor 320 of FIG. 3) to perform the functions or operations of the various elements.

[0126] Receiver 1610 is configured to receive RX signals from one or more other wireless communication devices. In some embodiments, receiver 1610 may receive one or more probe packets from a transmitting device via a wireless channel. Communication manager 1620 is configured to manage wireless communications with one or more other wireless communication devices. In some embodiments, CFR classification element 1622 may acquire a CSI associated with the one or more probe packets, wherein the CSI includes a set of values ​​classified into multiple subsets based on a number (M) of transmitting antennas of the transmitting device, a number (N) of receiving antennas of the wireless communication device, or a number (K) of tones across the bandwidth of the wireless channel, wherein each of these values ​​indicates a CFR associated with a corresponding transmitting antenna among the M transmitting antennas, a corresponding receiving antenna among the N receiving antennas, and a corresponding tone among the K tones. Transmitter 1630 is configured to transmit TX signals to one or more other wireless communication devices. In some implementations, the transmission element 1630 may transmit one or more CSI report frames, each CSI report frame carrying a corresponding subset of values ​​from the plurality of subsets.

[0127] FIG17 illustrates a block diagram of an exemplary wireless communication device 1700. In some embodiments, the wireless communication device 1700 may be configured to perform the process 1500 described above with reference to FIG15. The wireless communication device 1700 may be an exemplary embodiment of any of the RX devices 720, 820, 920, or 1020 in FIGS. 7-10. More specifically, the wireless communication device 1700 may be a chip, SoC, chipset, package, or device including at least one processor and at least one modem (e.g., a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0128] The wireless communication device 1700 includes a receiving element 1710, a communication manager 1720, and a transmitting element 1730. The communication manager 1720 further includes a CSI aggregation element 1722. A portion of the CSI aggregation element 1722 may be implemented at least partially in hardware or firmware. In some embodiments, the CSI aggregation element 1722 is at least partially implemented as software stored in memory (e.g., memory 240 of FIG. 2 or memory 330 of FIG. 3). For example, a portion of the CSI aggregation element 1722 may be implemented as non-transitory instructions (or "code") executable by a processor (e.g., processor 220 of FIG. 2 or processor 320 of FIG. 3) to perform the functions or operations of the various elements.

[0129] Receiver 1710 is configured to receive RX signals from one or more other wireless communication devices. In some embodiments, receiver 1710 may receive a first probe packet via a first wireless channel and may further receive a second probe packet via a second wireless channel. Communication manager 1620 is configured to manage wireless communication with one or more other wireless communication devices. In some embodiments, CSI aggregation element 1722 may acquire a first CSI associated with the first probe packet and may acquire a second CSI associated with the second probe packet. Transmitter 1630 is configured to transmit TX signals to one or more other wireless communication devices. In some embodiments, transmitter 1630 may transmit a CSI report frame including a first report field carrying the first CSI and a second report field carrying the second CSI.

[0130] The following numbered clauses describe examples of embodiments: 1. A method for wireless communication performed by a wireless communication device, comprising the steps of: receiving one or more probe packets from a transmitting device via a wireless channel; acquiring channel status information (CSI) associated with the one or more probe packets, the CSI comprising a set of values, the set of values ​​being categorized into a plurality of subsets based on a number (M) of transmitting antennas of the transmitting device, a number (N) of receiving antennas of the wireless communication device, or a number (K) of tones across the bandwidth of the wireless channel, wherein each of the equivalent values ​​indicates a channel frequency response (CFR) associated with a corresponding transmitting antenna among the M transmitting antennas, a corresponding receiving antenna among the N receiving antennas, and a corresponding tone among the K tones; and transmitting one or more CSI report frames, each CSI report frame carrying a corresponding subset of values ​​from the plurality of subsets. 2. The method of Clause 1, wherein the values ​​classified in the first subset of the plurality of subsets indicate CFRs associated with one or more of the K tones, and the values ​​classified in the second subset of the plurality of subsets indicate CFRs associated with one or more of the K tones that are different from the one or more of the first tones. 3. The method of any one of Clauses 1 or 2, wherein the one or more first tones represent a first extracted subset of the K tones, and the one or more second tones represent a second extracted subset of the K tones. 4. The method of any one of Clauses 1-3, wherein the one or more first tones span a first frequency band within the wireless channel bandwidth, and the one or more second tones span a second frequency band within the wireless channel bandwidth. 5. The method according to any one of Clauses 1-4, wherein the values ​​classified in the first subset of the plurality of subsets indicate the CFR associated with one or more of the M transmit antennas, and the values ​​classified in the second subset of the plurality of subsets indicate the CFR associated with one or more of the M transmit antennas that are different from the one or more first transmit antennas. 6. The method according to any one of Clauses 1-5, wherein the values ​​classified in the first subset of the plurality of subsets indicate the CFR associated with one or more of the N receive antennas, and the values ​​classified in the second subset of the plurality of subsets indicate the CFR associated with one or more of the N receive antennas that are different from the one or more first receive antennas. 7. The method according to any one of Clauses 1-6, wherein the values ​​classified in the first subset of the plurality of subsets represent the in-phase (I) component of one or more CFRs, and the values ​​classified in the second subset of the plurality of subsets represent the quadrature (Q) component of one or more CFRs.8. The method of any one of Clauses 1-6, wherein the values ​​classified in the first subset of the plurality of subsets represent the amplitude components of one or more CFRs, and the values ​​classified in the second subset of the plurality of subsets represent the phase components of the one or more CFRs. 9. The method of any one of Clauses 1-8, wherein each of the plurality of values ​​is associated with the same probe packet in the one or more probe packets. 10. The method of any one of Clauses 1-8, wherein the acquisition of the CSI comprises: acquiring one or more first values ​​from the plurality of values ​​associated with a first probe packet in the one or more probe packets, the one or more first values ​​being classified in the first subset of the plurality of subsets; and acquiring one or more second values ​​from the plurality of values ​​associated with a second probe packet in the one or more probe packets, the one or more second values ​​being classified in the second subset of the plurality of subsets. 11. The method of any one of Clauses 1-10, wherein each of the one or more CSI report frames further carries classification information indicating a subset of values ​​carried in the CSI report frame. 12. The method of any one of Clauses 1-11, further comprising the step of: receiving a CSI request indicating a corresponding subset of values ​​to be transmitted in each of the one or more CSI report frames. 13. A wireless communication device, comprising: an interface configured to: receive one or more probe packets from a transmission device via a wireless channel; and a processing system configured to: acquire channel status information (CSI) associated with the one or more probe packets, the CSI comprising a set of values ​​categorized into a plurality of subsets based on a number (M) of transmitting antennas of the transmission device, a number (N) of receiving antennas of the wireless communication device, or a number (K) of tones across the bandwidth of the wireless channel, wherein each of the equivalent values ​​indicates a channel frequency response (CFR) associated with a corresponding transmitting antenna among the M transmitting antennas, a corresponding receiving antenna among the N receiving antennas, and a corresponding tone among the K tones; the interface further configured to transmit one or more CSI report frames, each CSI report frame carrying a corresponding subset of values ​​from the plurality of subsets. 14. A wireless communication device pursuant to Clause 13, wherein the value in the first subset of the plurality of subsets indicates a CFR associated with one or more first tones among the K tones, and the value in the second subset of the plurality of subsets indicates a CFR associated with one or more second tones among the K tones that are different from the one or more first tones.15. A wireless communication device according to any one of Clauses 13 or 14, wherein the value classified in the first subset of the plurality of subsets indicates a CFR associated with one or more of the M transmitting antennas as first transmitting antennas, and the value classified in the second subset of the plurality of subsets indicates a CFR associated with one or more of the M transmitting antennas as second transmitting antennas, different from the one or more first transmitting antennas. 16. A wireless communication device according to any one of Clauses 13-15, wherein the value classified in the first subset of the plurality of subsets indicates a CFR associated with one or more of the N receiving antennas as first receiving antennas, and the value classified in the second subset of the plurality of subsets indicates a CFR associated with one or more of the N receiving antennas as second receiving antennas, different from the one or more first receiving antennas. 17. A wireless communication device according to any one of clauses 13-16, wherein the values ​​classified in a first subset of the plurality of subsets represent the in-phase (I) components of one or more CFRs, and the values ​​classified in a second subset of the plurality of subsets represent the quadrature (Q) components of the one or more CFRs. 18. A wireless communication device according to any one of clauses 13-17, wherein the values ​​classified in a first subset of the plurality of subsets represent the amplitude components of one or more CFRs, and the values ​​classified in a second subset of the plurality of subsets represent the phase components of the one or more CFRs. 19. A method for wireless communication performed by a wireless communication device, comprising the steps of: receiving a first probe packet via a first wireless channel; acquiring first channel status information (CSI) associated with the first probe packet; receiving a second probe packet via a second wireless channel; acquiring a second CSI associated with the second probe packet; and transmitting a CSI report frame including a first report field carrying the first CSI and a second report field carrying the second CSI. 20. The method of Clause 19, wherein the first probe packet and the second probe packet are received from the transmitting device. 21. The method of any one of Clauses 19 or 20, further comprising the step of: receiving a trigger frame from the transmitting device, wherein the CSI report frame is transmitted to the transmitting device in response to the trigger frame. 22. The method of Clause 19, wherein the first probe packet is received from a first transmitting device, and the second probe packet is received from a second transmitting device different from the first transmitting device. 23. The method of any one of Clauses 19 or 22, further comprising the step of: receiving a trigger frame from an initiating device different from each of the first and second transmitting devices, wherein the CSI report frame is transmitted to the initiating device in response to the trigger frame.24. The method of any one of Clauses 19-23, wherein the CSI report frame further includes a first control field carrying relay data associated with the first CSI, and includes a second control field carrying relay data associated with the second CSI. 25. The method of any one of Clauses 19-24, wherein the relay data includes at least one of the following: a vendor identifier (ID) associated with the wireless communication device, a media access control (MAC) address of the transmission device, an indication of whether a CSI was successfully acquired, a classification of channel frequency response (CFR) values, a preceding signal type associated with the received probe packet, a received signal strength indication (RSSI) per chain, a carrier frequency offset (CFO), an automatic gain control (AGC) per chain, a receive chain mask, a timestamp associated with the received probe packet, phase information for each chain, a modulation type associated with the received probe packet, an indication of whether the received probe packet conforms to a multi-user format, and the number of bits associated with each CFR value. 26. The method according to any one of Clauses 19-25, wherein the CSI report frame is a management frame having a frame body, the frame body including a first information element (IE) and a second IE, the first IE including the first control field and the first report field, and the second IE including the second control field and the second report field. 27. The method according to Clauses 19-25, wherein the CSI report frame is a management frame having a frame body including the first control field and the immediately following first report field, and including the second control field and the immediately following second report field, the first control field further carrying length information indicating the length of the first report field, and the second control field further carrying length information indicating the length of the second report field. 28. The method according to Clauses 19-25, wherein the CSI report frame is a management frame having a frame body including the first control field and the immediately following first report field, and including the second control field and the immediately following second report field, the CSI report frame further including one or more separators separating the first report field and the second control field. 29. A wireless communication device, comprising: an interface configured to: receive a first probe packet via a first wireless channel; and receive a second probe packet via a second wireless channel; and a processing system configured to: acquire first channel status information (CSI) associated with the first probe packet; and acquire a second CSI associated with the second probe packet; and the interface further configured to transmit a CSI report frame including a first report field carrying the first CSI and a second report field carrying the second CSI. 30. A wireless communication device pursuant to Clause 29, wherein the first probe packet and the second probe packet are received from the same transmission device.31. A wireless communication device pursuant to Clause 29, wherein the first probe packet is received from a first transmission device, and the second probe packet is received from a second transmission device different from the first transmission device.

[0131] As used herein, the phrase “at least one” or “one or more” in reference to a list of projects means any combination of such projects, including a single member. For example, “at least one of a, b or c” is intended to cover the following possibilities: only a, only b, only c, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b and c.

[0132] The various illustrative elements, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in conjunction with the embodiments disclosed herein can be implemented as electronic hardware, firmware, software, or a combination of hardware, firmware, or software, including the structures disclosed herein and their equivalents. The interchangeability of hardware, firmware, and software has been generally described in the functional profiles and illustrated in the various illustrative elements, blocks, modules, circuits, and processes described above. Whether such functions are implemented in hardware, firmware, or software depends on the specific application and the design constraints imposed on the overall system.

[0133] Various modifications to the embodiments described herein will be obvious to those skilled in the art, and the general principles defined herein can be applied to other embodiments without departing from the spirit or scope of this document. Therefore, the claim is not intended to be limited to the embodiments shown herein, but is to be given the broadest scope consistent with the content of this document, the principles and novel features disclosed herein.

[0134] Furthermore, the various functions described in the context of each independent implementation in this case can also be implemented in combination in a single implementation. Conversely, the various features described in the context of a single implementation can also be implemented independently in multiple implementations or in any suitable sub-combination. Thus, although a feature may be described above as functioning in a particular combination, or even initially claimed in this way, in some cases one or more features may be omitted from the claimed combination, and the claimed combination may refer to a sub-combination or a variation of a sub-combination.

[0135] Similarly, although operations are described in a specific order in the accompanying drawings, this should not be construed as requiring such operations to be performed in the specific order or sequential order shown, or requiring all illustrated operations to be performed to obtain the desired result. Furthermore, the drawings may schematically depict one or more exemplary processes in the form of flowcharts or schematic diagrams. However, other operations not described may be incorporated into the schematically illustrated exemplary processes. For example, one or more additional operations may be performed before, after, simultaneously with, or between any illustrated operation. In some cases, multiplexing and parallel processing may be advantageous. Furthermore, the separation of various system elements in the above embodiments should not be construed as requiring such separation in all embodiments, and it should be understood that the described program elements and systems can generally be integrated into a single software product or packaged into multiple software products. [Simplified Explanation of the Diagram]

[0011] Figure 1 illustrates a block diagram of an exemplary wireless system.

[0012] Figure 2 illustrates a block diagram of an exemplary wireless station (STA).

[0013] Figure 3 illustrates a block diagram of an exemplary access point (AP).

[0014] Figures 4A and 4B illustrate an exemplary radio frequency (RF) sensing system.

[0015] Figure 5 illustrates an exemplary Channel Status Information (CSI) matrix.

[0016] Figures 6A-6E illustrate exemplary CSI matrices, each of which includes a set of channel frequency response (CFR) values ​​categorized into multiple subsets.

[0017] Figure 7 illustrates a sequence diagram of exemplary message exchange between devices participating in a channel detection operation.

[0018] Figure 8 illustrates a sequence diagram of exemplary message exchanges between devices participating in a channel detection operation.

[0019] Figure 9 illustrates a sequence diagram of exemplary message exchange between devices participating in a channel detection operation.

[0020] Figure 10 illustrates a sequence diagram of exemplary message exchange between devices participating in a channel detection operation.

[0021] Figure 11 illustrates an exemplary CSI report message box for multiple captures.

[0022] Figure 12 illustrates an exemplary CSI report message box for multiple captures.

[0023] Figure 13 illustrates an exemplary CSI report message box for multiple captures.

[0024] Figure 14 illustrates an illustrative flowchart describing an exemplary wireless communication operation.

[0025] Figure 15 illustrates an illustrative flowchart describing an exemplary wireless communication operation.

[0026] Figure 16 illustrates a block diagram of an exemplary wireless communication device.

[0027] Figure 17 illustrates a block diagram of an exemplary wireless communication device.

[0028] Similar element symbols and reference numerals in the various figures indicate similar elements. [Biomaterial Storage]

[0137] Domestic storage information (please note in order of storage institution, date, and number): None. International storage information (please note in order of storage country, institution, date, and number): None.

Claims

1. A method for wireless communication performed by a wireless communication device, comprising the steps of: receiving one or more probe packets from a transmission device via a wireless channel; acquiring channel status information (CSI) associated with the one or more probe packets, the CSI comprising a set of values ​​categorized into a plurality of subsets based on a number (M) of transmitting antennas of the transmission device, a number (N) of receiving antennas of the wireless communication device, or a number (K) of tones across a bandwidth of the wireless channel, each of the equivalent values ​​indicating a channel frequency response (CFR) associated with a corresponding transmitting antenna among the M transmitting antennas, a corresponding receiving antenna among the N receiving antennas, and a corresponding tone among the K tones; and transmitting one or more CSI report frames, each CSI report frame carrying a corresponding subset of values ​​from the plurality of subsets.

2. The method of claim 1, wherein the equivalent indication in a first subset of the plurality of subsets is associated with a CFR of one or more first tones among the K tones, and the equivalent indication in a second subset of the plurality of subsets is associated with a CFR of one or more second tones among the K tones that are different from the one or more first tones.

3. The method according to claim 2, wherein the one or more first tones represent a first subset of the K tones, and the one or more second tones represent a second subset of the K tones.

4. The method according to claim 2, wherein the one or more first tones span a first frequency band within the wireless channel bandwidth, and the one or more second tones span a second frequency band within the wireless channel bandwidth.

5. The method of claim 1, wherein the equivalent value in a first subset of the plurality of subsets indicates the CFR associated with one or more of the first transmission antennas among the M transmission antennas, and the equivalent value in a second subset of the plurality of subsets indicates the CFR associated with one or more second transmission antennas among the M transmission antennas that are different from the one or more first transmission antennas.

6. The method of claim 1, wherein the equivalent value in a first subset of the plurality of subsets indicates the CFR associated with one or more first receiving antennas among the N receiving antennas, and the equivalent value in a second subset of the plurality of subsets indicates the CFR associated with one or more second receiving antennas among the N receiving antennas that are different from the one or more first receiving antennas.

7. The method of claim 1, wherein the equivalent value in a first subset of the plurality of subsets represents the in-phase (I) component of one or more CFRs, and the equivalent value in a second subset of the plurality of subsets represents the quadrature (Q) component of the one or more CFRs.

8. The method of claim 1, wherein the equivalent value in a first subset of the plurality of subsets represents the amplitude component of one or more CFRs, and the equivalent value in a second subset of the plurality of subsets represents the phase component of the one or more CFRs.

9. The method of request item 1, wherein each of the plurality of values ​​is associated with the same probe packet in the one or more probe packets.

10. The method of claim 1, wherein the acquisition step of the CSI includes the following steps: acquiring one or more first values ​​from the plurality of values ​​associated with a first probe packet among the one or more probe packets, the one or more first values ​​being classified into a first subset of the plurality of subsets; and acquiring one or more second values ​​from the plurality of values ​​associated with a second probe packet among the one or more probe packets, the one or more second values ​​being classified into a second subset of the plurality of subsets.

11. The method of claim 1, wherein each of the one or more CSI report frames further carries classification information indicating a subset of values ​​carried in the CSI report frame.

12. The method according to request item 1 further includes the following steps: receiving a CSI request indicating the corresponding subset of values ​​to be transmitted in each of the one or more CSI report frames.

13. A wireless communication device, comprising: An interface configured to receive one or more probe packets from a transmission device via a wireless channel; A processing system configured to: acquire Channel Status Information (CSI) associated with the one or more probe packets, the CSI comprising a set of values ​​categorized into multiple subsets based on a number (M) of transmitting antennas of the transmitting device, a number (N) of receiving antennas of the wireless communication device, or a number (K) of tones across a bandwidth of the wireless channel, wherein each of the equivalent values ​​indicates a channel frequency response (CFR) associated with a corresponding transmitting antenna among the M transmitting antennas, a corresponding receiving antenna among the N receiving antennas, and a corresponding tone among the K tones; the interface is further configured to transmit one or more CSI report frames, each CSI report frame carrying a corresponding subset of values ​​from the multiple subsets.

14. The wireless communication device according to claim 13, wherein the equivalent indication classified in a first subset of the plurality of subsets is associated with a CFR of one or more first tones among the K tones, and the equivalent indication classified in a second subset of the plurality of subsets is associated with a CFR of one or more second tones among the K tones that are different from the one or more first tones.

15. The wireless communication device according to claim 13, wherein the equivalent value in a first subset of the plurality of subsets indicates the CFR associated with one or more of the M transmission antennas, and the equivalent value in a second subset of the plurality of subsets indicates the CFR associated with one or more of the M transmission antennas that are different from the one or more first transmission antennas.

16. The wireless communication device according to claim 13, wherein the equivalent value in a first subset of the plurality of subsets is associated with a CFR of one or more first receiving antennas among the N receiving antennas, and the equivalent value in a second subset of the plurality of subsets is associated with a CFR of one or more second receiving antennas among the N receiving antennas that are different from the one or more first receiving antennas.

17. The wireless communication device according to claim 13, wherein the equivalent value in a first subset of the plurality of subsets represents the in-phase (I) component of one or more CFRs, and the equivalent value in a second subset of the plurality of subsets represents the quadrature (Q) component of the one or more CFRs.

18. The wireless communication device according to claim 13, wherein the equivalent value in a first subset of the plurality of subsets represents the amplitude component of one or more CFRs, and the equivalent value in a second subset of the plurality of subsets represents the phase component of the one or more CFRs.

Images