Patent Publication Number: US-2023138224-A1

Title: Wlan sensing frame exchange protocol

Description:
PRIORITY CLAIM 
     This application is a continuation of U.S. patent application Ser. No. 16/897,963, filed Jun. 10, 2020, which claims priority under 35 U.S.C. 119(e) to U.S. Provisional Patent Application Ser. No. 62/864,647, filed Jun. 21, 2019 [reference number AC3254-Z], entitled Wi-Fi Sensing Protocol Design and Frame Exchange, each of which is incorporated herein by reference in its entirety. 
    
    
     TECHNICAL FIELD 
     Embodiments pertain to wireless local area networks (WLANs). Some embodiments pertain to WLAN sensing. Some embodiments pertain to the IEEE 802.11 WLAN Sensing Study Group. Some embodiments pertain to the IEEE 802.11bf WLAN Sensing Task Group. Some embodiments relate to WLAN sensing using high-efficiency (HE) trigger-based (TB) physical-layer protocol data units (PPDUs) (HE TB PPDUs). 
     BACKGROUND 
     WLAN sensing enables motion detection, gesture recognition as well as biometric measurement by using WLAN signals. It creates opportunities for service providers within the home security, health care, enterprise, and building automation and management markets and many more. Thus, there are general needs for a WLAN sensing protocol for various WLAN sensing implementations. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates classification of a sensing initiator and a sensing responder and classification of sensing transmitter and receiver, in accordance with some embodiments of a WLAN sensing protocol; 
         FIG.  2    illustrates scenario one in which an access point (AP) is operating as a sensing initiator and the sensing receiver in accordance with some embodiments of the WLAN sensing protocol; and 
         FIG.  3    illustrates scenario two in which the AP is operating as the sensing initiator and a sensing transmitter in accordance with some embodiments of the WLAN sensing protocol. 
         FIG.  4    illustrates scenario three in which a station (STA1) is operating as a sensing initiator and the STA1 is operating as a sensing receiver in accordance with some embodiments of the WLAN sensing protocol. 
         FIG.  5    illustrates scenario four in which a STA1 is operating as a sensing initiator and the STA1 is operating as a sensing transmitter in accordance with some embodiments of the WLAN sensing protocol. 
         FIG.  6    illustrates scenario five in which a STA1 is operating as a sensing initiator and another STA (STA2) is operating as a sensing receiver in accordance with some embodiments of the WLAN sensing protocol. 
         FIG.  7    illustrates the framework of the WLAN sensing protocol in accordance with some embodiments. 
         FIG.  8    is a flow diagram of the negotiation phase of the WLAN sensing protocol in accordance with some embodiments. 
         FIG.  9    illustrates the measurement and report phases of WLAN sensing protocol for scenario one in accordance with some embodiments. 
         FIG.  10    illustrates the measurement and report phases of WLAN sensing protocol for scenario two in accordance with some embodiments. 
         FIG.  11    illustrates the measurement and report phases of WLAN sensing protocol for scenario three in accordance with some embodiments. 
         FIG.  12    illustrates the measurement and report phases of WLAN sensing protocol for scenario four in accordance with some embodiments. 
         FIG.  13    illustrates the measurement and report phases of WLAN sensing protocol for scenario five in accordance with some embodiments. 
         FIG.  14    illustrates a functional diagram of an exemplary communication station, in accordance with one or more example embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The following description and the drawings sufficiently illustrate specific embodiments to enable those skilled in the art to practice them. Other embodiments may incorporate structural, logical, electrical, process, and other changes. Portions and features of some embodiments may be included in, or substituted for, those of other embodiments. Embodiments set forth in the claims encompass all available equivalents of those claims. 
     In some embodiments, an apparatus of a wireless communication device is configurable for WLAN sensing. The wireless communication device may either be an AP or a non-AP STA. In accordance with some embodiments, the apparatus may comprise processing circuitry and memory. In these embodiments, the processing circuitry is to configure the wireless communication device to perform a WLAN sensing protocol within a basic service set (BSS) comprising one or more stations (STAs) (STA1  104  and STA2  106 ) including an access point station (AP STA). The WLAN sensing protocol may include a discovery phase  202 , a negotiation phase  206 , a measurement phase  208 , and a reporting phase  210 , as illustrated in  FIG.  7   . The WLAN sensing protocol may also include a discovery phase  202  and a calibration phase  204 . As illustrated in  FIG.  1   , to perform the WLAN sensing protocol, the processing circuitry may configure the wireless communication device to operate as either a sensing initiator or a sensing responder. The processing circuitry may also configure the wireless communication device to operate as a sensing transmitter and/or a sensing receiver. 
     In some IEEE 802.11ad or IEEE 802.11ay embodiments (e.g., 60 GHz), the wireless communication device may be a DMG STA and may perform a WLAN sensing protocol within PBSS or IBSS. In some of these embodiments, the AP may operate as a PCP for DMG stations. 
     In some embodiments, during the discovery phase  202 , the STAs of the BSS that support WLAN sensing are discovered, at least one of the STAs is identified as a sensing receiver, and one or more of the STAs are identified as potential sensing transmitters. In some embodiments, during the negotiation phase  206 , a measurement frequency is determined and one or more of the STAs, identified as the potential sensing transmitters, are designated as sensing transmitters. In some embodiments, during the measurement phase  208 , the one or more STAs that are designated as the sensing transmitters are configured to transmit sensing packets for sensing measurements by one or more STAs that are designated as the sensing receivers. In some embodiments, during the reporting phase  210 , the sensing measurements are provided to the sensing initiator. 
     In some embodiments, the sensing measurements may comprise a channel measurement, such as channel state information (CSI), although the scope of the embodiments is not limited in this respect. In some embodiments, a separate discovery phase  202  may not be needed as the operations of the discovery phase  202  may take place during conventional WLAN discovery operations. In some embodiments, the reporting phase  210  is optional. For example, if the sensing initiator is the sensing receiver, reporting of the sensing measurements may not be necessary. In some embodiments, the reporting phase  210  may be performed if the sensing initiator is not the sensing receiver. 
     In the embodiments illustrated in  FIG.  2    and  FIG.  9    (scenario 1), if the wireless communication device is an AP STA  102  and is operating as the sensing initiator and if the AP STA  102  is designated as the sensing receiver during the negotiation phase  206 , during the measurement phase  208 , the AP STA  102  is configured to encode a trigger frame  806  for transmission to the STAs (STA1  104  and STA2  106 ) that have been designated as sensing transmitters during the negotiation phase  206 . The trigger frame  806  triggers the STAs to (regularly and/or periodically) transmit uplink sensing packets to the AP STA  102  (i.e., designated as a sensing receiver) in accordance with either an UL OFDMA or UL technique. In these embodiments, the AP STA  102  is configured to determine the sensing measurements from the UL sensing packets. 
     In the embodiments illustrated in  FIG.  3    and  FIG.  10    (scenario 2) if the wireless communication device is an AP STA  102  and is operating as the sensing initiator, and if the AP STA  102  is designated as a sensing transmitter during the negotiation phase  206 , during the measurement phase  208  the processing circuitry of the AP STA  102  is configured to transmit a downlink (DL) sensing packet to the STAs (STA1  104  and STA2  106 ) that have been designated as the sensing receivers during the negotiation phase  206 . The downlink sensing packet may either be broadcast by the AP STA  102  or transmitted in accordance with either a DL OFDMA or DL MU-MIMO technique to each of the STAs designated as sensing receivers. In these embodiments, the AP STA  102  may encode a trigger frame  806  for transmission following the DL sensing packet  810 . The trigger frame  806  may trigger transmission of measurement report  812  frames by each of the STAs designated as sensing receivers. In these embodiments, during the reporting phase  210 , the AP STA  102  is configured to receive measurement reports  812  from the STAs designated as sensing receivers. The measurement report  812  frames may comprise indicators of the sensing measurements that were measured by the STAs. 
     In the embodiments illustrated in  FIG.  4    and  FIG.  11    (scenario 3) if the wireless communication device is a non-AP STA (STA1  104 ) and is operating as the sensing initiator and the sensing receiver, during the discovery phase  202 , the STA1  104  sends a request to the AP STA  102  to initiate a sensing service, the STA1  104  indicates its availability as the sensing receiver, and the AP STA  102  receives identities of the STA2s  106  that are available as the sensing transmitters. During the negotiation phase  206 , the STA1  104 , operating as the sensing receiver, receives an indication from the AP STA  102  which of the STA2s  106  are designated as the sensing transmitters and a measurement periodicity is determined. In these embodiments, during the measurement phase  208 , the STA1  104  receives UL sensing packets transmitted by the STA2s  106  operating as sensing transmitters in response to a trigger frame  806  transmitted by the AP STA  102 . During the measurement phase  208 , the STA1  104  further receives DL sensing packet  810   s  transmitted by the AP STA  102  if the AP STA  102  is configured to operate as one of the sensing transmitters. During the measurement phase  208 , the STA1  104  may receive the UL sensing packets from the STA2s  106  and the DL sensing packet  810   s  from the AP STA  102  in accordance with the measurement periodicity. In these embodiments, the UL sensing packets may be transmitted by the STA2s  106  in accordance with an UL OFDMA or UL MU-MIMO technique and the UL sensing packets may be transmitted concurrently with the DL sensing packet  810  transmitted by the AP STA  102 , although this is not a requirement. 
     In the embodiments illustrated in  FIG.  5    and  FIG.  12    (scenario 4), if the wireless communication device is a non-AP STA (STA1  104 ) and is operating as the sensing initiator, during the discovery phase  202 , the STA1  104  sends a request to the AP to initiate sensing service. In some embodiments, during the discovery phase  202 , the AP may also find STAs that are available to be transmitters (e.g., STA2s). During the measurement phase  208 , if the STA1  104  is operating as a sensing transmitter, the STA1  104  is configured to decode a trigger frame  806  from the AP STA  102  to trigger the transmission of UL sensing packets from the STA2s  106  designated as sensing transmitters, and encode an UL sensing packet  808  for transmission to the AP STA  102  in response to the trigger frame  806 . In these embodiments, the AP STA  102  is operating as the sensing receive. The UL sensing packet  808  may be multiplexed with UL sensing packet  808   s  transmitted by other STAs operating as the sensing transmitters. In these embodiments, during the reporting phase  210 , the STA1  104 , operating as the sensing initiator, is configured to decode a measurement report  812  sent from the AP STA  102 . The measurement report  812  may comprise indicators of the sensing measurements based on the UL sensing packet  808   s  received from the STA2s  106  by the AP STA  102 . in these embodiments, if the STA1  104  is to operate as the sensing transmitter, the STA1  104  indicates to the AP STA  102  its availability as a sensing transmitter during the discovery phase  202 . In some embodiments, the STA1  104 , when operating as the sensing initiator may receive during the negotiation phase  206  the identities of the STA2s  106  that are available as sensing transmitters from the AP STA  102 . In some embodiments, the AP STA  102  may use an out-of-band technique to communicate the STA2s  106  that are available as potential sensing transmitters. In some of these embodiments, during the negotiation phase  206 , the STA1  104  may indicate to the AP STA  102  which of the STA2s  106  are to be used as sensing transmitters, although this is not a requirement as the AP STA  102  may determine which of the STA2s  106  are to be used as sensing transmitters. In some embodiments during the negotiation phase  206 , the STA1  104 , operating as a sensing transmitter, may request a measurement periodicity. In these embodiments, the UL sensing packet  808   s  may be multiplexed in the frequency domain or the spatial domain. In some other embodiments, the UL sensing packets  808  may be multiplexed in time and separately triggered (i.e., triggered one after the other). In some embodiments, the measurement periodicity may further be negotiated between the AP and other transmitters. 
     In the embodiments illustrated in  FIG.  6    and  FIG.  13    (scenario 5) if the wireless communication device is a non-AP STA (STA1  104 ) and is operating as the sensing initiator. In these embodiments, the AP STA  102  is not operating as a sensing receiver. Another non-AP STA (STA2  106 ) of the BSS may be operating as the sensing receiver. During the discovery phase  202 , the STA1  104  sends a request to the AP STA  102  to initiate sensing service. During the measurement phase  208 , if the STA1  104  is operating as a sensing transmitter, the STA1  104  is configured to decode a trigger frame  806  from the AP STA  102  to trigger transmission of an UL sensing packet  808  and encode the UL sensing packet  808  for transmission to the AP STA  102  in response to the trigger frame  806 . In these embodiments, during the reporting phase  210 , the STA1  104  is configured to decode a measurement report  812  received from the AP STA  102 . The measurement report  812  may comprise sensor measurements that were measured by the other one or more non-AP STAs (STA2)  106  operating as sensing receivers. In these embodiments, if the STA1  104  is to operate as the sensing transmitter, the STA1  104  indicates to the AP STA  102  its availability as a sensing transmitter during the discovery phase  202 . In these embodiments, if the STA1  104  does not operate as a sensing transmitter, the STA1  104  does not indicates to the AP STA  102  its availability as a sensing transmitter during the discovery phase  202 , and the STA1  104  does not need to decode the trigger frame  806  from the AP STA  102  and does not encode the UL sensing packet  808 . In some embodiments, a trigger frame  814  may be used by the AP STA  102  to trigger transmission of measurement report  812  by the STA2  106  for subsequent transmission to the STA1  104 . 
     In some embodiments, the WLAN sensing protocol may include a calibration phase  204 , as illustrated in  FIG.  7   . During the calibration phase  204 , baseline channel estimates may be established for transmitter receiver pairs comprising the sensing receiver and each of the sensing transmitters. The calibration phase  204  is optional and may not be necessary. 
     In some embodiments, the WLAN sensing protocol may further comprise a teardown phase  212  following the reporting phase  210 , as illustrated in  FIG.  7   . During the teardown phase  212 , roles of the STAs of the BSS for performing the WLAN sensing protocol are ended. In some embodiments, the teardown phase  212  may comprise an exchange of messages indicating that the sensing measurements are no longer needed and the STAs may be stripped of their role designation. In some embodiments, the sensing initiator may initiate the teardown stage by sending a message to the AP to notify the sensing transmitters and the sensing receivers. 
     In some embodiments, a sensing session may have a one-time discovery and negotiation phase, but may have multiple measurement and reporting phases, followed by a single teardown phase. In these embodiments, re-negotiation may be performed during the sensing session if necessary, although the scope of the embodiments is not limited in this respect. 
     As illustrated in  FIG.  8   , in some embodiments the negotiation phase  206  may include the sensing initiator sending a sensing request frame  802  to the sensing responder. After an ACK, the sensing responder may send a sensing response frame  804  back to the sensing initiator. The sensing initiator may acknowledge the sensing response frame  804  with an ACK. In some embodiments, the sensing protocol provides for rules and frame exchanges used to establish a sensing session. The sensing session may comprise a successful establishment of a series of uniquely identifiable measurement event(s) through the use of a Sensing Request/Response frame exchange. 
     In some of these embodiments, the sensing initiator may be a HE STA or a DMG STA or another  802 . 11  STA that sets up a sensing session by transmitting a sensing request frame  802 . The sensing responder(s) may be a HE STA or a DMG STA that agrees to participate in a sensing session by transmitting a sensing response frame  804  in response to the reception of a sensing request frame  802 . Sensing transmitter(s) may be a subset of the group formed by the initiator and responder(s), plus possibly legacy STAs, that transmit at each measurement event(s) of a sensing session. Sensing receiver(s) may be a subset of the group formed by the initiator and responder(s) that receive at each measurement event(s) of a sensing session. In some embodiments, the sensing initiators and responders may be part of a BSS and hence authenticated, however the scope of the embodiments is not limited in this respect as some embodiments apply to multi-AP sensing operations. 
     In some embodiments, the STA is an HE STA configured to operate in accordance with an IEEE 802.11ax standard within a 2.4 GHz, a 5 GHz or a 6 GHz band, and wherein the trigger frames  806  comprise extended trigger frames  806  or trigger frame  806  variants. In some embodiments, the STA may be an EHT STA configured to operate in accordance with an IEEE 802.11be standard or draft standard. In some embodiments, the STA is a DMG STA configured to operate in accordance with IEEE 802.11ay or IEEE 802.11ad standard within a 60 GHz band, and wherein the trigger frame  806   s  comprise a CTS-to-self frame appended with a control trailer. 
     In some embodiments, a physical layer protocol data unit may be a physical layer conformance procedure (PLCP) protocol data unit (PPDU). In some embodiments, the AP and STAs may communicate in accordance with one of the IEEE 802.11 standards. IEEE draft specification IEEE P802.11ax/D4.0, February 2019 is incorporated herein by reference in its entirety. In some embodiments, the AP and STAs may be directional multi-gigabit (DMG) STAs or enhanced DMG (EDMG) STAs configured to communicate in accordance with IEEE 802.11ad standard or IEEE draft specification IEEE P802.11ay, February 2019, which is incorporated herein by reference. In some embodiments, an AP or other STA may decode the HE TB PPDUs received from the client devices, and may estimate channel state information (CSI) for a radio link associated with each of the client devices based on an HE-long-training field (LTF) (HE-LTF) of an associated one of the HE-TB PPDUs received from one of the client devices. In accordance with these embodiments, the AP or other STA may process changes in the CSI of the radio links over time for a WLAN sensing application. It should be noted that a sensing receiver that receives packets for sensing measurements does not need to decode the packets as the STA may use the preamble for determining the sensing measurements. In some embodiments, during the measurement phase  208 , the sensing measurements may be performed based on a long-training field (LTF) of received packets. 
       FIG.  14    shows a functional diagram of an exemplary wireless communication device  1400 , in accordance with one or more example embodiments of the present disclosure. In one embodiment, communication device  1400  may be suitable for use as an AP-STA or non-AP STA in accordance with some embodiments described above. The communication station  1400  may also be suitable for use as a handheld device, a mobile device, a cellular telephone, a smartphone, a tablet, a netbook, a wireless terminal, a laptop computer, a wearable computer device, a femtocell, a high data rate (HDR) subscriber station, an access point, an access terminal, or other personal communication system (PCS) devices. In some embodiments, devices participating in WLAN sensing may comprise a plug-in device dedicated to device sensing, a smart IoT device, or other device. 
     The communication station  1400  may include communications circuitry  1402  and a transceiver  1410  for transmitting and receiving signals to and from other communication stations using one or more antennas  1401 . The communications circuitry  1402  may include circuitry that can operate the physical layer (PHY) communications and/or medium access control (MAC) communications for controlling access to the wireless medium, and/or any other communications layers for transmitting and receiving signals. The communication station  1400  may also include processing circuitry  1406  and memory  1408  arranged to perform the operations described herein. In some embodiments, the communications circuitry  1402  and the processing circuitry  1406  may be configured to perform operations detailed in the above figures, diagrams, and flows. 
     In accordance with some embodiments, the communications circuitry  1402  may be arranged to contend for a wireless medium and configure frames or packets for communicating over the wireless medium. The communications circuitry  1402  may be arranged to transmit and receive signals. The communications circuitry  1402  may also include circuitry for modulation/demodulation, upconversion/downconversion, filtering, amplification, etc. In some embodiments, the processing circuitry  1406  of the communication station  1400  may include one or more processors. In other embodiments, two or more antennas  1401  may be coupled to the communications circuitry  1402  arranged for sending and receiving signals. The memory  1408  may store information for configuring the processing circuitry  1406  to perform operations for configuring and transmitting message frames and performing the various operations described herein. The memory  1408  may include any type of memory, including non-transitory memory, for storing information in a form readable by a machine (e.g., a computer). For example, the memory  1408  may include a computer-readable storage device, read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices and other storage devices and media. 
     In some embodiments, the communication station  1400  may be part of a portable wireless communication device, such as a personal digital assistant (PDA), a laptop or portable computer with wireless communication capability, a web tablet, a wireless telephone, a smartphone, a wireless headset, a pager, an instant messaging device, a digital camera, an access point, a television, a medical device (e.g., a heart rate monitor, a blood pressure monitor, etc.), a wearable computer device, or another device that may receive and/or transmit information wirelessly. 
     In some embodiments, the communication station  1400  may include one or more antennas  1401 . The antennas  1401  may include one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas, or other types of antennas suitable for transmission of RF signals. In some embodiments, instead of two or more antennas, a single antenna with multiple apertures may be used. In these embodiments, each aperture may be considered a separate antenna. In some multiple-input multiple-output (MIMO) embodiments, the antennas may be effectively separated for spatial diversity and the different channel characteristics that may result between each of the antennas and the antennas of a transmitting station. 
     In some embodiments, the communication station  1400  may include one or more of a keyboard, a display, a non-volatile memory port, multiple antennas, a graphics processor, an application processor, speakers, and other mobile device elements. The display may be an LCD screen including a touch screen. 
     Although the communication station  1400  is illustrated as having several separate functional elements, two or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs), and/or other hardware elements. For example, some elements may include one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements of the communication station  1400  may refer to one or more processes operating on one or more processing elements. 
     Certain embodiments may be implemented in one or a combination of hardware, firmware, and software. Other embodiments may also be implemented as instructions stored on a computer-readable storage device, which may be read and executed by at least one processor to perform the operations described herein. A computer-readable storage device may include any non-transitory memory mechanism for storing information in a form readable by a machine (e.g., a computer). For example, a computer-readable storage device may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash-memory devices, and other storage devices and media. In some embodiments, the communication station  1400  may include one or more processors and may be configured with instructions stored on a computer-readable storage device. 
     The Abstract is provided to comply with 37 C.F.R. Section 1.72(b) requiring an abstract that will allow the reader to ascertain the nature and gist of the technical disclosure. It is submitted with the understanding that it will not be used to limit or interpret the scope or meaning of the claims. The following claims are hereby incorporated into the detailed description, with each claim standing on its own as a separate embodiment.