Patent Description:
A wireless local area network (WLAN) may be formed by one or more access points (APs) that provide a shared wireless communication medium for use by a number of client devices also referred to as stations (STAs). The basic building block of a WLAN conforming to the Institute of Electrical and Electronics Engineers (IEEE) <NUM> family of standards is a Basic Service Set (BSS), which is managed by an AP. Each BSS is identified by a Basic Service Set Identifier (BSSID) that is advertised by the AP. An AP periodically broadcasts beacon frames to enable any STAs within wireless range of the AP to establish or maintain a communication link with the WLAN.

WLAN sensing or WiFi sensing generally refers to a WLAN in which one or more WLAN devices monitor or map the environment using standard WLAN signals. For example, a WiFi sensing system may use the signal reflections off of walls or other objects, including people, to map and measure the environment, and to identify and track objects within that environment. Document IEEE <NUM>-<NUM>/o842ro, titled "A Channel Measurement Procedure for WLAN Sensing", represents a contribution by Intel dated June <NUM>, <NUM>. Document IEEE <NUM>-<NUM>/0145r5, titled "Collaborative WLAN Sensing - Follow Ups", represents a contribution by LG Electronics dated March <NUM>, <NUM>.

The invention is defined by the independent claims that accompany this disclosure. Any examples and embodiments of the description not falling within the scope of the claims do not form part of the invention as defined by the independent claims.

One innovative aspect of the subject matter described in this disclosure can be implemented in a first wireless communication device. An example first wireless communication device includes an interface configured to obtain a first wireless transmission, the first wireless transmission including a transmit (TX) parameter information element (IE). The interface is also configured to obtain a second wireless transmission. The first wireless communication device also includes a processing system configured to obtain one or more transmission parameters for one or more second wireless communication devices associated with the TX parameter IE. The processing system is also configured to obtain one or more wireless sensing measurements associated with the second wireless transmission and the one or more transmission parameters.

In some aspects, the processing system is further configured to verify an integrity of the TX parameter IE associated with a message integrity code (MIC) in the first wireless transmission. In some aspects, the MIC is configured to verify an integrity of at least an access category (AC) or traffic stream (TS) associated with the first wireless transmission.

In some aspects, the first wireless transmission is obtained from an access point (AP), and the TX parameter IE indicates that each of the one or more second wireless communication devices have static transmission parameters, and the second wireless transmission is obtained from one of the one or more second wireless communication devices.

In some aspects, the first wireless transmission includes a frame obtained from a non-AP station (STA) and the second wireless transmission is obtained from the non-AP STA. In some aspects, the frame is included in an aggregated media access control (MAC) protocol data unit (A-MPDU). In some aspects, the frame includes an initial physical layer (PHY) protocol data unit (PPDU) of an aggregated PPDU (A-PPDU). In some aspects, the frame includes a public frame transmitted at a basic modulation and coding scheme (MCS). In some aspects, the TX parameter IE is obtained with each transmission received from the non-AP STA. In some aspects, the TX parameter IE is obtained periodically from the non-AP STA. In some aspects, the TX parameter IE indicates a transmit power of the non-AP STA. In some aspects, the TX parameter IE indicates one or more of changes in multiple-input multiple-output (MIMO) precoding used by the non-AP STA and changes in beamforming and antenna selection settings used by the non-AP STA. In some aspects an index in the TX parameter IE indicates a change in the MIMO precoding or beamforming and antenna selection settings used by the non-AP STA. In some aspects, the TX parameter IE indicates whether or not the non-AP STA has moved since the non-AP STA transmitted a previous frame including a TX parameter IE.

Another innovative aspect of the subject matter described in this disclosure can be implemented as a method for wireless communication. In some implementations, the method may be performed by a first wireless communication device. The method may include receiving a first wireless transmission, the first wireless transmission including a transmit (TX) parameter information element (IE). The method includes receiving one or more transmission parameters for one or more second wireless communication devices associated with the TX parameter IE. The method includes receiving a second wireless transmission from one of the one or more second wireless communication devices. The method includes receiving one or more wireless sensing measurements associated with the second wireless transmission and the one or more transmission parameters.

In some aspects, the method includes verifying an integrity of the TX parameter IE associated with a message integrity code (MIC) in the first wireless transmission. In some aspects, the MIC is configured to verify an integrity of at least an access category (AC) or traffic stream (TS) associated with the first wireless transmission.

In some aspects, the first wireless transmission is received from an access point (AP), and the TX parameter IE indicates that each of the one or more second wireless communication devices have static transmission parameters.

In some aspects, the first wireless transmission includes a frame received from a non-AP station (STA) and the second wireless transmission is received from the non-AP STA. In some aspects, the frame is included in an aggregated media access control (MAC) protocol data unit (A-MPDU). In some aspects, the frame includes an initial physical layer (PHY) protocol data unit (PPDU) of an aggregated PPDU (A-PPDU). In some aspects, the frame includes a public frame transmitted at a basic modulation and coding scheme (MCS). In some aspects, the TX parameter IE is received with each transmission received from the non-AP STA. In some aspects, the TX parameter IE is received periodically from the non-AP STA. In some aspects, the TX parameter IE indicates a transmit power of the non-AP STA. In some aspects, the TX parameter IE indicates one or more of changes in multiple-input multiple-output (MIMO) precoding used by the non-AP STA and changes in beamforming and antenna selection settings used by the non-AP STA. In some aspects an index in the TX parameter IE indicates a change in the MIMO precoding or beamforming and antenna selection settings used by the non-AP STA. In some aspects, the TX parameter IE indicates whether or not the non-AP STA has moved since the non-AP STA transmitted a previous frame including a TX parameter IE.

Another innovative aspect of the subject matter described in this disclosure can be implemented as a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium stores instructions for execution by one or more processors of a first wireless communication device. Execution of the instructions causes the first wireless communication device to perform operations including receiving a first wireless transmission, the first wireless transmission including a transmit (TX) parameter information element (IE). The operations include receiving one or more transmission parameters for one or more second wireless communication devices associated with the TX parameter IE. The operations include receiving a second wireless transmission from one of the one or more second wireless communication devices. The operations include receiving one or more wireless sensing measurements associated with the second wireless transmission and the one or more transmission parameters.

In some aspects, the operations include verifying an integrity of the TX parameter IE associated with a message integrity code (MIC) in the first wireless transmission. In some aspects, the MIC is configured to verify an integrity of at least an access category (AC) or traffic stream (TS) associated with the first wireless transmission.

Another innovative aspect of the subject matter described in this disclosure can be implemented as a method for wireless communication. In some implementations, the method may be performed by a first wireless communication device. The method may include receiving a first wireless transmission including a transmit (TX) parameter information element (IE). The method includes, in response to a message integrity code (MIC) in the first wireless transmission not verifying an integrity of the TX parameter IE, discarding the first wireless transmission. The method includes, in response to the MIC verifying the integrity of the TX parameter IE, receiving one or more transmission parameters for one or more second wireless communication devices associated with the TX parameter IE, receiving a second wireless transmission from one of the one or more second wireless communication devices, and receiving one or more wireless sensing measurements associated with the second wireless transmission and the one or more transmission parameters.

In some aspects, the MIC is configured to verify an integrity of at least an access category (AC) or traffic stream (TS) associated with the first wireless transmission.

Another innovative aspect of the subject matter described in this disclosure can be implemented in a first wireless communication device. An example first wireless communication device includes an interface configured to obtain a first wireless transmission, the first wireless transmission including a transmit (TX) parameter information element (IE). The interface is also configured to obtain a second wireless transmission. The first wireless communication device also includes a processing system configured to, in response to a message integrity code (MIC) in the first wireless transmission not verifying an integrity of the TX parameter IE, discard the first wireless transmission. The processing system is configured to, in response to the MIC verifying the integrity of the TX parameter IE, obtain one or more transmission parameters for one or more second wireless communication devices associated with the TX parameter IE, and obtain one or more wireless sensing measurements associated with the second wireless transmission and the one or more transmission parameters.

In some aspects, the first wireless transmission is obtained from an access point (AP), and the TX parameter IE indicates that each of the one or more second wireless communication devices have static transmission parameters.

Details of one or more implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description.

The following description is directed to some particular implementations for the purposes of describing innovative aspects of this disclosure. However, a person having ordinary skill in the art will readily recognize that the teachings herein can be applied in a multitude of different ways. The described implementations can be implemented in any device, system, or network that is capable of transmitting and receiving radio frequency (RF) signals according to one or more of the Institute of Electrical and Electronics Engineers (IEEE) <NUM> standards, the IEEE <NUM> standards, the Bluetooth® standards as defined by the Bluetooth Special Interest Group (SIG), or the Long Term Evolution (LTE), <NUM>, <NUM>, or <NUM> (New Radio (NR)) standards promulgated by the 3rd Generation Partnership Project (3GPP), among others. The described implementations can be implemented in any device, system, or network that is capable of transmitting and receiving RF signals according to one or more of the following technologies or techniques: 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 multi-user (MU) MIMO. The described implementations also can be implemented using other wireless communication protocols or RF signals suitable for use in one or more of a wireless personal area network (WPAN), a wireless local area network (WLAN), a wireless wide area network (WWAN), or an internet of things (IOT) network.

An AP periodically broadcasts beacon frames to enable any STAs within wireless range of the AP to establish or maintain a communication link with the WLAN. The STAs may wake from sleep states or low power modes at periodic time intervals such as target beacon transmission times (TBTTs) to receive the beacon frames. A beacon frame may include basic network information, discovery information, capabilities, and the like. Some beacon frames include a traffic indication map (TIM) element indicating the presence of queued downlink (DL) data for one or more of the STAs. Other beacon frames may include a delivery traffic indication map (DTIM) indicating whether the AP has queued DL data scheduled for transmission to one or more of the STAs. In some instances, the DTIM also may indicate the group address for a group of STAs.

Various implementations relate generally to wireless sensing using transmissions from wireless communication devices in a wireless network. For example, some implementations implement WiFi sensing using one or more APs and one or more STAs in a WLAN. WiFi sensing may involve the transmission and monitoring changes in channel state information (CSI) of what might be considered standard WiFi PHY signals, such as frames or packets. The reflections and other alterations to the transmitted signals may be used to map and measure the environment around the wireless communication devices, including monitoring the position of objects within the environment. In other words, WiFi sensing effectively allows transmission and reception of WLAN signals to determine and monitor positions, movements, and characteristics of nearby objects. In some cases, a wireless communication device participating in WiFi sensing operations may operate in a full-duplex mode, allowing one antenna(s) to transmit while the other antenna(s) are receiving.

Any suitable techniques may be used to detect and process changes in CSI of received signals. Changes in CSI may be detected, for example, based on a cross-correlation of one or more sequences in transmitted frames (such as in a channel estimation field). The detection may be based on the cross-correlation (CC) results. For example, the CC may be performed to detect reflections and scatters surrounding the wireless node. Changes in CSI due to these reflections may appear as a new tap in the CC output. The wireless node may generate (such as based on the CC results) a table including a distance, angle, material classification, and speed for each target (such as a detected object). Distance may be determined, for example, by measuring a round trip time for a transmitted signal to return to the receiving antenna of the wireless node. In some cases, a sensing device may determine an angle or arrival (AoA) of a received frame, and based on the angle of arrival, the device may generate position information or three dimensional measurement information (such as based on a known location of a transmitting device, the sensing device, or a nearby object). In some cases, a sensing device may determine a direction of motion of an object. In some cases, multiple sensing devices may provide raw measurement data for a central device (such as an AP) to process and determine position sensor data (such as position/location/direction).

One of the challenges in wireless sensing, such as WiFi sensing, is the coordination between different wireless communication devices, for example, to establish which wireless communication devices are transmitting and when, and to establish the expected transmission parameters for each transmitting device. Such transmission parameters may include, for example, transmission power, MIMO precoding, beamforming (BF) and antenna selection, and so on.

Conventional WiFi sensing techniques may establish a session between wireless communication devices to exchange transmission parameters for the frames to be used for sensing. For example, the transmission parameters may be included in one or more frames which are generated in response to a request from one or more of the devices involved in the session. Subsequently, frames to be used for sensing purposes may be transmitted according to the transmission parameters, and subsequently received and measured by one or more receiving devices in the session. However, such session-based WiFi sensing systems may present a number of drawbacks. For example, frames transmitted by devices not included in an established session may not be used for sensing, even when those frames are transmitted within an environment for which WiFi sensing is desirable. Further, frames transmitted by wireless communication devices in an established session, but which are transmitted for other purposes, such as for data transmission, may not be used for sensing. Further, session-based techniques may not support sessions extending across more than one BSS. Additionally, conventional techniques may not support multiple responder sessions initiated by non-AP devices, and thus many frames transmitted are not used for sensing, requiring the transmission of additional frames for sensing purposes, which may lead to congestion in the wireless environment.

Further, it may be desirable to verify the integrity of frames used for exchanging transmission parameters, in order to reduce the risk of man-in-the-middle attacks on WiFi sensing systems. That is, if another wireless communication device transmits one or more frames purporting to advertise transmission parameters for wireless sensing, it may be desirable to verify the integrity of those transmission parameters in order for accurate sensing measurements to be reliably performed.

Implementations of the present disclosure may provide protected session-less WiFi sensing. In some aspects, a STA may not change its transmission parameters, and may communicate this to an AP, and the AP may share this information in a broadcast message such as a beacon. For example, such a broadcast message may include identifiers, such as MAC addresses, of one or more STAs whose transmission parameters do not change. These identifiers may be included in one or more information elements (IEs) included in such a broadcast message. In some other aspects, a wireless device may advertise its transmission parameters in one or more frames transmitted by the wireless device for other purposes, such as in one or more frames for data transmission. For example, the transmission parameters may be provided within a TX parameters IE and included in one or more frames transmitted by the wireless device. In some aspects, the transmission parameters may be included in a public frame included in a data aggregated medium access control (MAC) protocol data unit (MPDU), such as a public frame included in a data A-MPDU. In some other aspects, the transmission parameters may be included in a public frame transmitted as part of a transmission opportunity (TXOP). Such a public frame may be transmitted at a lower modulation and coding scheme (MCS) as compared to other transmissions of the TXOP. In some other aspects, the transmission parameters may be included in a heading physical layer convergence protocol (PLCP) protocol data unit (PPDU) of an aggregated PPDU (A-PPDU). Such a heading PPDU also may have a lower MCS as compared to other PPDUs of the A-PPDU.

Further, some aspects of the present disclosure may provide an indication of the integrity of the transmission parameters. For example, such an indication of integrity may be provided by modifying the broadcast/multicast integrity protocol (BIP) to provide an indication of an access category (AC) and traffic stream (TS) of the corresponding TXOP. Additionally, a TX parameters action frame category may be defined to include the TX parameters IE and a management message integrity code (MIC) element. This management MIC element may include a new subfield indicating the AC/TS. Accordingly, when such an action frame is used to communicate the TX parameters IE, a receiving wireless device may verify the integrity of the action frame using the management MIC.

Particular implementations of the subject matter described in this disclosure can be implemented to realize one or more of the following potential advantages. A first wireless communication device may communicate its transmission parameters to any other wireless communication devices within range, and those receiving devices may use the communicated transmission parameters for WiFi sensing without previous establishment of a WiFi sensing session. In some implementations, frames transmitted for purposes unrelated to WiFi sensing may be used for WiFi sensing after communication of the transmitting devices transmission parameters. Additionally, frames transmitted by devices within communication range may be used for WiFi sensing regardless of the BSS to which the devices belong, provided that the wireless communication devices communicate their transmission parameters to one another (or to each BSS). Further, a wireless communication device receiving a frame containing transmission parameters for WiFi sensing may verify the integrity of the communicated parameters, improving reliability of subsequent WiFi sensing operations. In addition, aspects of the example implementations may allow for better sensing of moving objects. A moving object may depart from a coverage range of a first wireless communication device, and into the coverage range of a second wireless communication device. Aspects of the sessionless wireless sensing described herein may allow for wireless sensing of the moving object to seamlessly transition from using the signals transmitted by the first wireless communication device to using the signals transmitted by the second wireless communication device.

<FIG> shows a block diagram of an example wireless communication network <NUM>. According to some aspects, the example wireless communication network <NUM> can be an example of a wireless local area network (WLAN) such as a Wi-Fi network (and will hereinafter be referred to as WLAN <NUM>). For example, the WLAN <NUM> can be a network implementing at least one of the IEEE <NUM> family of wireless communication protocol standards (such as that defined by the IEEE <NUM>-<NUM> specification or amendments thereof including, but not limited to, <NUM>. 11ah, <NUM>. 11ad, <NUM>. 11ay, <NUM>. 11ax, <NUM>. 11az, <NUM>. 11ba, and <NUM>. The WLAN <NUM> may include numerous wireless communication devices such as an access point (AP) <NUM> and multiple stations (STAs) <NUM>. While only one AP <NUM> is shown, the example wireless communication network <NUM> also can include multiple APs <NUM>.

Each of the STAs <NUM> also may be referred to as a mobile station (MS), a mobile device, a mobile handset, a wireless handset, an access terminal (AT), a user equipment (UE), a subscriber station (SS), or a subscriber unit, among other possibilities. The STAs <NUM> may represent various devices such as mobile phones, personal digital assistants (PDAs), other handheld devices, netbooks, notebook computers, tablet computers, laptops, display devices (for example, TVs, computer monitors, navigation systems, among others), music or other audio or stereo devices, remote control devices ("remotes"), printers, kitchen or other household appliances, key fobs (for example, for passive keyless entry and start (PKES) systems), among other possibilities.

A single AP <NUM> and an associated set of STAs <NUM> may be referred to as a basic service set (BSS), which is managed by the respective AP <NUM>. <FIG> additionally shows an example coverage area <NUM> of the AP <NUM>, which may represent a basic service area (BSA) of the WLAN <NUM>. The BSS may be identified to users by a service set identifier (SSID), as well as to other devices by a basic service set identifier (BSSID), which may be a medium access control (MAC) address of the AP <NUM>. The AP <NUM> periodically broadcasts beacon frames ("beacons") including the BSSID to enable any STAs <NUM> within wireless range of the AP <NUM> to "associate" or re-associate with the AP <NUM> to establish a respective communication link <NUM> (hereinafter also referred to as a "Wi-Fi link"), or to maintain a communication link <NUM>, with the AP <NUM>. For example, the beacons can include an identification of a primary channel used by the respective AP <NUM> as well as a timing synchronization function for establishing or maintaining timing synchronization with the AP <NUM>. The AP <NUM> may provide access to external networks to various STAs <NUM> in the WLAN via respective communication links <NUM>.

To establish a communication link <NUM> with an AP <NUM>, each of the STAs <NUM> is configured to perform passive or active scanning operations ("scans") on frequency channels in one or more frequency bands (for example, the <NUM>, <NUM>, <NUM>, or <NUM> bands). To perform passive scanning, a STA <NUM> listens for beacons, which are transmitted by respective APs <NUM> at a periodic time interval referred to as the target beacon transmission time (TBTT) (measured in time units (TUs) where one TU may be equal to <NUM> microseconds (µs)). To perform active scanning, a STA <NUM> generates and sequentially transmits probe requests on each channel to be scanned and listens for probe responses from APs <NUM>. Each STA <NUM> may be configured to identify or select an AP <NUM> with which to associate based on the scanning information obtained through the passive or active scans and to perform authentication and association operations to establish a communication link <NUM> with the selected AP <NUM>. The AP <NUM> assigns an association identifier (AID) to the STA <NUM> at the culmination of the association operations, which the AP <NUM> uses to track the STA <NUM>.

As a result of the increasing ubiquity of wireless networks, a STA <NUM> may have the opportunity to select one of many BSSs within range of the STA or to select among multiple APs <NUM> that together form an extended service set (ESS) including multiple connected BSSs. An extended network station associated with the WLAN <NUM> may be connected to a wired or wireless distribution system that may allow multiple APs <NUM> to be connected in such an ESS. As such, a STA <NUM> can be covered by more than one AP <NUM> and can associate with different APs <NUM> at different times for different transmissions. Additionally, after association with an AP <NUM>, a STA <NUM> also may be configured to periodically scan its surroundings to find a more suitable AP <NUM> with which to associate. For example, a STA <NUM> that is moving relative to its associated AP <NUM> may perform a "roaming" scan to find another AP <NUM> having more desirable network characteristics such as a greater received signal strength indicator (RSSI) or a reduced traffic load.

In some cases, STAs <NUM> may form networks without APs <NUM> or other equipment other than the STAs <NUM> themselves. One example of such a network is an ad hoc network (or wireless ad hoc network). Ad hoc networks may alternatively be referred to as mesh networks or peer-to-peer (P2P) networks. In some cases, ad hoc networks may be implemented within a larger wireless network such as the WLAN <NUM>. In such implementations, while the STAs <NUM> may be capable of communicating with each other through the AP <NUM> using communication link <NUM>, STAs <NUM> also can communicate directly with each other via direct wireless links <NUM>. Additionally, two STAs <NUM> may communicate via a direct communication link regardless of whether both STAs <NUM> are associated with and served by the same AP <NUM>. In such an ad hoc system, one or more of the STAs <NUM> may assume the role filled by the AP <NUM> in a BSS. Such a STA <NUM> may be referred to as a group owner (GO) and may coordinate transmissions within the ad hoc network. Examples of direct wireless links <NUM> include Wi-Fi Direct connections, connections established by using a Wi-Fi Tunneled Direct Link Setup (TDLS) link, and other P2P group connections.

The APs <NUM> and STAs <NUM> may function and communicate (via the respective communication links <NUM>) according to the IEEE <NUM> family of wireless communication protocol standards (such as that defined by the IEEE <NUM>-<NUM> specification or amendments thereof including, but not limited to, <NUM>. 11ah, <NUM>. 11ad, <NUM>. 11ay, <NUM>. 11ax, <NUM>. 11az, <NUM>. 11ba, and <NUM>. These standards define the WLAN radio and baseband protocols for the PHY and medium access control (MAC) layers. The APs <NUM> and STAs <NUM> transmit and receive wireless communications (hereinafter also referred to as "Wi-Fi communications") to and from one another in the form of physical layer convergence protocol (PLCP) protocol data units (PPDUs). The APs <NUM> and STAs <NUM> in the WLAN <NUM> may transmit PPDUs over an unlicensed spectrum, which may be a portion of spectrum that includes frequency bands traditionally used by Wi-Fi technology, such as the <NUM> band, the <NUM> band, the <NUM> band, the <NUM> band, and the <NUM> band. Some implementations of the APs <NUM> and STAs <NUM> described herein also may communicate in other frequency bands, such as the <NUM> band, which may support both licensed and unlicensed communications. The APs <NUM> and STAs <NUM> also can be configured to communicate over other frequency bands such as shared licensed frequency bands, where multiple operators may have a license to operate in the same or overlapping frequency band or bands.

Each of the frequency bands may include multiple sub-bands or frequency channels. For example, PPDUs conforming to the IEEE <NUM>. 11n, <NUM>. 11ac, and <NUM>. 11ax standard amendments may be transmitted over the <NUM> and <NUM> bands, each of which is divided into multiple <NUM> channels. As such, these PPDUs are transmitted over a physical channel having a minimum bandwidth of <NUM>, but larger channels can be formed through channel bonding. For example, PPDUs may be transmitted over physical channels having bandwidths of <NUM>, <NUM>, <NUM>, or <NUM> by bonding together multiple <NUM> channels.

Each PPDU is a composite structure that includes a PHY preamble and a payload in the form of a PLCP service data unit (PSDU). The information provided in the preamble may be used by a receiving device to decode the subsequent data in the PSDU. In instances in which PPDUs are transmitted over a bonded channel, the preamble fields may be duplicated and transmitted in each of the multiple component channels. The PHY preamble may include both a legacy portion (or "legacy preamble") and a non-legacy portion (or "non-legacy preamble"). The legacy preamble may be used for packet detection, automatic gain control, and channel estimation, among other uses. The legacy preamble also may generally be used to maintain compatibility with legacy devices. The format of, coding of, and information provided in the non-legacy portion of the preamble is based on the particular IEEE <NUM> protocol to be used to transmit the payload.

Access to the shared wireless medium is generally governed by a distributed coordination function (DCF). With a DCF, there is generally no centralized master device allocating time and frequency resources of the shared wireless medium. On the contrary, before a wireless communication device, such as an AP <NUM> or a STA <NUM>, is permitted to transmit data, it must wait for a particular time and contend for access to the wireless medium. In some implementations, the wireless communication device may be configured to implement the DCF through the use of carrier sense multiple access (CSMA) with collision avoidance (CA) (CSMA/CA) techniques and timing intervals. Before transmitting data, the wireless communication device may perform a clear channel assessment (CCA) and determine that the appropriate wireless channel is idle. The CCA includes both physical (PHY-level) carrier sensing and virtual (MAC-level) carrier sensing. Physical carrier sensing (or packet detection (PD)) is accomplished via a measurement of the received signal strength of a valid frame, which is compared to a value to determine whether the channel is busy. For example, if the received signal strength of a detected preamble is above the value, the medium is considered busy. Physical carrier sensing also includes energy detection (ED). Energy detection involves measuring the total energy the wireless communication device receives regardless of whether the received signal represents a valid frame. If the total energy detected is above a value, the medium is considered busy. Virtual carrier sensing is accomplished via the use of a network allocation vector (NAV), an indicator of a time when the medium may next become idle. The NAV is reset each time a valid frame is received that is not addressed to the wireless communication device. The NAV effectively serves as a time duration that must elapse before the wireless communication device may contend for access even in the absence of a detected symbol or even if the detected energy is below the value.

The DCF is implemented through the use of time intervals. These time intervals include the slot time (or "slot interval") and the inter-frame space (IFS). The slot time is the basic unit of timing and may be determined based on one or more of a transmit-receive turnaround time, a channel sensing time, a propagation delay, and a MAC processing time. Measurements for channel sensing are performed for each slot. All transmissions may begin at slot boundaries. Example varieties of IFS include: the short IFS (SIFS), the distributed IFS (DIFS), the extended IFS (EIFS), or the arbitration IFS (AIFS). For example, the DIFS may be defined as the sum of the SIFS and two times the slot time. The values for the slot time and IFS may be provided by a suitable standard specification, such as one of the IEEE <NUM> family of wireless communication protocol standards (such as that defined by the IEEE <NUM>-<NUM> specification or amendments thereof including, but not limited to, <NUM>. 11ah, <NUM>. 11ad, <NUM>. 11ay, <NUM>. 11ax, <NUM>. 11az, <NUM>. 11ba, and <NUM>.

When the NAV reaches <NUM>, the wireless communication device performs physical carrier sensing. If the channel remains idle for the appropriate IFS (for example, a DIFS), the wireless communication device initiates a backoff timer, which represents a duration of time that the device must sense the medium to be idle before it is permitted to transmit. The backoff timer is decremented by one slot each time the medium is sensed to be idle during a corresponding slot interval. If the channel remains idle until the backoff timer expires, the wireless communication device becomes the holder (or "owner") of a transmit opportunity (TXOP) and may begin transmitting. The TXOP is the duration of time the wireless communication device can transmit frames over the channel after it has won contention for the wireless medium. If, on the other hand, one or more of the carrier sense mechanisms indicate that the channel is busy, a MAC controller within the wireless communication device will not permit transmission.

Each time the wireless communication device generates a new PPDU for transmission in a new TXOP, it randomly selects a new backoff timer duration. The available distribution of numbers that may be randomly selected for the backoff timer is referred to as the contention window (CW). If, when the backoff timer expires, the wireless communication device transmits the PPDU, but the medium is still busy, there may be a collision. Additionally, if there is otherwise too much energy on the wireless channel resulting in a poor signal-to-noise ratio (SNR), the communication may be corrupted or otherwise not successfully received. In such instances, the wireless communication device may not receive a communication acknowledging the transmitted PDU within a timeout interval. The MAC may increase the CW exponentially, for example, doubling it, and randomly select a new backoff timer duration from the CW before each attempted retransmission of the PPDU. Before each attempted retransmission, the wireless communication device may wait a duration of DIFS and, if the medium remains idle, proceed to initiate the new backoff timer. There are different CW and TXOP durations for each of the four access categories (ACs): voice (AC_VO), video (AC_VI), background (AC_BK), and best effort (AC_BE). This enables particular types of traffic to be prioritized in the network.

<FIG> shows a block diagram of an example wireless communication device <NUM>. In some implementations, the wireless communication device <NUM> can be an example of a device for use in a STA such as one of the STAs <NUM> described with reference to <FIG>. In some implementations, the wireless communication device <NUM> can be an example of a device for use in an AP such as the AP <NUM> described with reference to <FIG>. The wireless communication device <NUM> is capable of transmitting (or outputting for transmission) and receiving wireless communications (for example, in the form of wireless packets). For example, the wireless communication device <NUM> can be configured to transmit and receive packets in the form of physical layer convergence protocol (PLCP) protocol data units (PPDUs) and medium access control (MAC) protocol data units (MPDUs) conforming to an IEEE <NUM> wireless communication protocol standard, such as that defined by the IEEE <NUM>-<NUM> specification or amendments thereof including, but not limited to, <NUM>. 11ah, <NUM>. 11ad, <NUM>. 11ay, <NUM>. 11ax, <NUM>. 11az, <NUM>. 11ba, and <NUM>.

The wireless communication device <NUM> can be, or can include, a chip, system on chip (SoC), chipset, package, or device that includes one or more modems <NUM>, for example, a Wi-Fi (IEEE <NUM> compliant) modem. In some implementations, the one or more modems <NUM> (collectively "the modem <NUM>") additionally include a WWAN modem (for example, a 3GPP <NUM> LTE or <NUM> compliant modem). In some implementations, the wireless communication device <NUM> also includes one or more radios <NUM> (collectively "the radio <NUM>"). In some implementations, the wireless communication device <NUM> further includes one or more processors, processing blocks, or processing elements <NUM> (collectively "the processor <NUM>"), and one or more memory blocks or elements <NUM> (collectively "the memory <NUM>").

The modem <NUM> can include an intelligent hardware block or device such as, for example, an application-specific integrated circuit (ASIC) among other possibilities. The modem <NUM> is generally configured to implement a PHY layer. For example, the modem <NUM> is configured to modulate packets and to output the modulated packets to the radio <NUM> for transmission over the wireless medium. The modem <NUM> is similarly configured to obtain modulated packets received by the radio <NUM> and to demodulate the packets to provide demodulated packets. In addition to a modulator and a demodulator, the modem <NUM> may further include digital signal processing (DSP) circuitry, automatic gain control (AGC), a coder, a decoder, a multiplexer, and a demultiplexer. For example, while in a transmission mode, data obtained from the processor <NUM> is provided to a coder, which encodes the data to provide encoded bits. The encoded bits are mapped to points in a modulation constellation (using a selected MCS) to provide modulated symbols. The modulated symbols may be mapped to a number NSS of spatial streams or a number NSTS of space-time streams. The modulated symbols in the respective spatial or space-time streams may be multiplexed, transformed via an inverse fast Fourier transform (IFFT) block, and subsequently provided to the DSP circuitry for Tx windowing and filtering. The digital signals may be provided to a digital-to-analog converter (DAC). The resultant analog signals may be provided to a frequency upconverter, and ultimately, the radio <NUM>. In implementations involving beamforming, the modulated symbols in the respective spatial streams are precoded via a steering matrix prior to their provision to the IFFT block.

While in a reception mode, digital signals received from the radio <NUM> are provided to the DSP circuitry, which is configured to acquire a received signal, for example, by detecting the presence of the signal and estimating the initial timing and frequency offsets. The DSP circuitry is further configured to digitally condition the digital signals, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correcting for I/Q imbalance), and applying digital gain to ultimately obtain a narrowband signal. The output of the DSP circuitry may be fed to the AGC, which is configured to use information extracted from the digital signals, for example, in one or more received training fields, to determine an appropriate gain. The output of the DSP circuitry also is coupled with the demodulator, which is configured to extract modulated symbols from the signal and, for example, compute the logarithm likelihood ratios (LLRs) for each bit position of each subcarrier in each spatial stream. The demodulator is coupled with the decoder, which may be configured to process the LLRs to provide decoded bits. The decoded bits from all of the spatial streams are fed to the demultiplexer for demultiplexing. The demultiplexed bits may be descrambled and provided to the MAC layer (the processor <NUM>) for processing, evaluation, or interpretation.

The radio <NUM> generally includes at least one radio frequency (RF) transmitter (or "transmitter chain") and at least one RF receiver (or "receiver chain"), which may be combined into one or more transceivers. For example, the RF transmitters and receivers may include various DSP circuitry including at least one power amplifier (PA) and at least one low-noise amplifier (LNA), respectively. The RF transmitters and receivers may, in turn, be coupled to one or more antennas. For example, in some implementations, the wireless communication device <NUM> can include, or be coupled with, multiple transmit antennas (each with a corresponding transmit chain) and multiple receive antennas (each with a corresponding receive chain). The symbols output from the modem <NUM> are provided to the radio <NUM>, which transmits the symbols via the coupled antennas. Similarly, symbols received via the antennas are obtained by the radio <NUM>, which provides the symbols to the modem <NUM>.

The processor <NUM> can include an intelligent hardware block or device such as, for example, a processing core, a processing block, a central processing unit (CPU), a microprocessor, a microcontroller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a programmable logic device (PLD) such as a field programmable gate array (FPGA), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processor <NUM> processes information received through the radio <NUM> and the modem <NUM>, and processes information to be output through the modem <NUM> and the radio <NUM> for transmission through the wireless medium. For example, the processor <NUM> may implement a control plane and MAC layer configured to perform various operations related to the generation and transmission of MPDUs, frames, or packets. The MAC layer is configured to perform or facilitate the coding and decoding of frames, spatial multiplexing, space-time block coding (STBC), beamforming, and OFDMA resource allocation, among other operations or techniques. In some implementations, the processor <NUM> may generally control the modem <NUM> to cause the modem to perform various operations described herein.

The memory <NUM> can include tangible storage media such as random-access memory (RAM) or read-only memory (ROM), or combinations thereof. The memory <NUM> also can store non-transitory processor- or computer-executable software (SW) code containing instructions that, when executed by the processor <NUM>, cause the processor to perform various operations described herein for wireless communication, including the generation, transmission, reception, and interpretation of MPDUs, frames, or packets. For example, various functions of components disclosed herein, or various blocks or steps of a method, operation, process, or algorithm disclosed herein, can be implemented as one or more modules of one or more computer programs.

<FIG> shows a block diagram of an example AP <NUM>. For example, the AP <NUM> can be an example implementation of the AP <NUM> described with reference to <FIG>. The AP <NUM> includes a wireless communication device (WCD) <NUM>. For example, the wireless communication device <NUM> may be an example implementation of the wireless communication device <NUM> described with reference to <FIG>. The AP <NUM> also includes multiple antennas <NUM> coupled with the wireless communication device <NUM> to transmit and receive wireless communications. In some implementations, the AP <NUM> additionally includes an application processor <NUM> coupled with the wireless communication device <NUM>, and a memory <NUM> coupled with the application processor <NUM>. The AP <NUM> further includes at least one external network interface <NUM> that enables the AP <NUM> to communicate with a core network or backhaul network to gain access to external networks including the Internet. For example, the external network interface <NUM> may include one or both of a wired (for example, Ethernet) network interface and a wireless network interface (such as a WWAN interface). Any of the aforementioned components can communicate with other components directly or indirectly, over at least one bus. The AP <NUM> further includes a housing that encompasses the wireless communication device <NUM>, the application processor <NUM>, the memory <NUM>, and at least portions of the antennas <NUM> and external network interface <NUM>.

<FIG> shows a block diagram of an example STA <NUM>. For example, the STA <NUM> can be an example implementation of the STA <NUM> described with reference to <FIG>. The STA <NUM> includes a wireless communication device <NUM>. For example, the wireless communication device <NUM> may be an example implementation of the wireless communication device <NUM> described with reference to <FIG>. The STA <NUM> also includes one or more antennas <NUM> coupled with the wireless communication device <NUM> to transmit and receive wireless communications. The STA <NUM> additionally includes an application processor <NUM> coupled with the wireless communication device <NUM>, and a memory <NUM> coupled with the application processor <NUM>. In some implementations, the STA <NUM> further includes a user interface (UI) <NUM> (such as a touchscreen or keypad) and a display <NUM>, which may be integrated with the UI <NUM> to form a touchscreen display. In some implementations, the STA <NUM> may further include one or more sensors <NUM> such as, for example, one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors. Ones of the aforementioned components can communicate with other ones of the components directly or indirectly, over at least one bus. The STA <NUM> further includes a housing that encompasses the wireless communication device <NUM>, the application processor <NUM>, the memory <NUM>, and at least portions of the antennas <NUM>, UI <NUM>, and display <NUM>. In some other implementations, the STA <NUM> may include a processing system and an interface configured to perform the described functions.

Aspects of the present disclosure provide improved communications for wireless devices configured to operate in accordance with the IEEE <NUM> family of standards. Emerging versions of the IEEE <NUM> standards may support WiFi sensing, such as IEEE <NUM>. For example, some WiFi sensing techniques may establish a session between devices to exchange transmission parameters for the frames to be used for sensing. For example, the transmission parameters may be included in one or more frames which are generated in response to a request from one or more of the devices involved in the session. Frames to be used for sensing purposes may be transmitted according to the transmission parameters, and subsequently received and measured by one or more receiving devices in the session. However, such session-based WiFi sensing systems may present a number of drawbacks. For example, frames transmitted by devices not included in an established session may not be used for sensing, even when those frames are transmitted within an environment for which WiFi sensing is desirable. Further, frames transmitted by devices in an established session, but which are transmitted for other purposes, such as for data transmission, may not be used for sensing. Further, session-based techniques may not support sessions extending across more than one BSS. Additionally, session-based techniques may not support multiple responder sessions initiated by non-AP devices, and thus many frames transmitted are not used for sensing, requiring the transmission of additional frames for sensing purposes, which may lead to congestion.

Further, it may be desirable to verify the integrity of frames used for exchanging transmission parameters, in order to reduce the risk of man-in-the-middle attacks on WiFi sensing systems. That is, if another device transmits one or more frames purporting to advertise transmission parameters for wireless sensing, it may be desirable to verify the integrity of those transmission parameters in order for accurate sensing measurements to be reliably performed.

<FIG> shows an example wireless sensing system <NUM>. With respect to <FIG>, the wireless sensing system <NUM> is shown to include a transmitting device <NUM>, a receiving device <NUM>, and an object <NUM>. The transmitting device may be any suitable device capable of transmitting wireless signals, such as the AP <NUM> or STA <NUM> of <FIG>, or the wireless communication device <NUM> of <FIG>. The receiving device <NUM> may be any suitable device capable of receiving wireless signals, such as the AP <NUM> or STA <NUM> of <FIG>, or the wireless communication device <NUM> of <FIG>. The object <NUM> may be an object in the vicinity of the transmitting device <NUM> and the receiving device <NUM>, such as a wall, a piece of furniture, a person or animal, or any suitable object capable of affecting the CSI of transmitted wireless signals, for example by deflection, reflection, and so on. Note that while <FIG> shows a signal having its CSI altered by the object <NUM> by reflection, that detectable changes in CSI of transmitted wireless signals may occur without reflection, for example, the object <NUM> may block part of a transmitted signal, resulting in the receiving device <NUM> detecting a signal having lower power than would be detected without the presence of the object <NUM>. In one example, the transmitting device <NUM> may transmit a transmission <NUM>, and the CSI of the transmission <NUM> may be affected by the object <NUM>, for example deflecting or reflecting off of the object <NUM> and be received at the receiving device <NUM> as CSI altered Tx <NUM>. Note that while <FIG> shows the transmitting device <NUM> and the receiving device <NUM> as separate, in some aspects, a transmitting device also may receive one or more reflections of its own transmissions and perform wireless sensing based on those received reflections. Further, note that while <FIG> shows only a single transmitting device <NUM> and a single receiving device <NUM>, other wireless sensing systems may have any number of transmitting and receiving devices.

A receiving device, such as receiving device <NUM>, may use any suitable techniques may be used to detect and process changes in the CSI of received signals, such as reflection <NUM>, in addition to changes in CSI due to blocking, deflection, and so on which may be caused by nearby objects. Changes in CSI may be detected, for example, based on a cross-correlation of one or more sequences in transmitted frames (such as in a channel estimation field). The detection may be based on the cross-correlation (CC) results. The detection and processing may also be based on subtraction of normalized CSI, for example based on measurements on different frames or training sequences. For example, the CC may be performed to detect reflections and scatters surrounding the receiving device <NUM>. Changes in CSI due to these deflections, reflections, and so on may appear as a new tap in the CC output. The receiving device <NUM> may generate (such as based on the CC results) a table including a distance, angle, material classification, and speed for each target (such as a detected object <NUM>). Distance may be determined, for example, by measuring a round trip time for a transmitted signal to return to the receiving antenna of the receiving device <NUM>. In some cases, a sensing device may determine an angle or arrival of a reflected frame, and based on the angle of arrival, the receiving device <NUM> may generate position information or three dimensional measurement information (such as based on a known location of transmitting device <NUM>, the receiving device <NUM>, or object <NUM>). In some cases, the receiving device <NUM> may determine a direction of motion of an object, such as object <NUM>. In some cases, multiple sensing devices may provide raw measurement data for a central device (such as an AP) to process and determine position sensor data (such as position/location/direction). In some aspects, one or more machine learning (ML) models may be used for correlating changes in CSI with aspects of the detected object <NUM>, such as a position, distance, material classification, speed, and so on.

Session-based WiFi sensing techniques may have significant limitations as to which wireless devices and which wireless transmissions may be used for sensing measurements. For example, a WiFi sensing session may be restricted to a single BSS, such that other wireless devices outside of the BSS but within transmission range of the BSS cannot participate in the WiFi sensing session. Further, frames transmitted for non-sensing purposes may not be used for sensing.

<FIG> shows a diagram <NUM> of three BSSs <NUM>, <NUM>, and <NUM> and their associated STAs. In the example of <FIG>, each of the STAs belongs to only one BSS. In some implementations, the diagram <NUM> may be an overhead diagram depicting relative locations of the wireless devices. A first BSS <NUM> may include STAs <NUM> and <NUM> and an AP <NUM>, a second BSS <NUM> may include STAs <NUM> and <NUM> and an AP <NUM>, while a third BSS <NUM> may include STAs <NUM> and <NUM> and an AP <NUM>. The STA <NUM> may be within transmission range of one or more devices belonging to BSSs <NUM>-<NUM>, but is not associated with any of these BSSs. For session-based WiFi sensing techniques, a first session may be established among one or more devices belonging to BSS <NUM>, a second session may be established among one or more devices belonging to BSS <NUM>, and a third session may be established among one or more devices belonging to BSS <NUM>. However, transmission from devices in one BSS may not be used for sensing by devices in the other BSSs. For example, STA <NUM> may be capable of receiving transmissions from STA <NUM>, AP <NUM>, and STA <NUM>, but these signals may not be used for sensing, because session-based WiFi sensing techniques may not support sessions extending across multiple BSSs.

Implementations of the subject matter disclosed herein may remove the requirement for a session to be established prior to sensing. Such techniques may be called sessionless WiFi sensing techniques. For example, sessionless WiFi sensing techniques may allow wireless devices to include information about transmission parameters in other transmissions, including transmission for other non-sensing purposes, such as data transmissions. A receiving device may receive such transmissions and use the information about transmission parameters for WiFi sensing measurements. For example, the included information may indicate one or more transmission parameters for one or more wireless devices, and the receiving device may subsequently receive one or more transmissions from one of these one or more wireless devices and make one or more wireless sensing measurements for the subsequently received transmissions based on the transmission parameters. Sessionless WiFi sensing techniques may therefore not be restricted to devices within a single BSS and may use a wider variety of transmitted frames for making sensing measurements.

<FIG> shows a diagram <NUM> showing a plurality of wireless devices, each belonging to at most one BSS, illustrating some benefits of sessionless techniques for WiFi sensing. <FIG> shows the same wireless devices and BSSs as depicted in <FIG>; however, sessionless WiFi sensing techniques may allow more wireless devices to exchange signals for sensing, and for a wider variety of transmitted frames to be used for sensing measurements. For example, STA <NUM>, STA <NUM>, AP <NUM>, and STA <NUM> may be within communication range of each other. Information about transmission parameters may be exchanged, in one or more transmission (TX) parameter information elements (IEs), and subsequent transmissions by one of these wireless devices may be received by the other wireless devices and used for WiFi sensing measurements.

<FIG> shows an example TX parameter IE <NUM> which may be used for communicating transmission parameters. With regard to <FIG>, the TX parameter IE may include a transmit power field and a parameter index field. For example, the transmit power field may include one byte (<NUM> bits or one octet), and the parameter index field may include <NUM> bytes (<NUM> bits or two octets). The transmit power field may indicate a transmission power for the wireless device transmitting a frame including the TX parameter IE <NUM>. This transmission power may be expressed in any suitable manner, such as an absolute transmission power, an index corresponding to a transmission power, and so on. The parameter index may indicate changes in one or more transmission parameters of transmissions of the wireless device transmitting a frame including the TX parameter IE <NUM>. The parameter index may indicate changes in transmission parameters such as MIMO precoding, information about beamforming and antenna selection, and so on. When the index is unchanged with respect to a previously transmitted TX parameter IE, the transmission parameters are indicated to be unchanged. Such transmission parameters also may indicate that the device transmitting the TX parameter IE has moved since the device previously transmitted a TX parameter IE. For example, this indication may indicate whether or not the device has moved at least a threshold distance since the previous TX parameter IE was transmitted. In some aspects, the parameter index subfield may be a counter, such as a free-running counter, which increases in value by a known amount, such as one, each time one of the transmission parameters for a transmitted frame is changed with respect to a previous transmission addressed to a same target. In some aspects, the parameter index may also increase when the transmitting device has moved with respect to a position where the transmitting device transmitted the previous transmission. The TX parameter IE <NUM> may optionally include a stationary field, indicating whether or not the transmitting device has moved since the previous transmission, or whether the transmitting device has been stationary since the previous transmission.

<FIG> shows another example TX parameter IE <NUM> which may be used for indicating transmission parameters. While the TX parameter IE <NUM> indicated transmission parameters for a single wireless device, the TX parameter IE <NUM> may indicate that a number of wireless devices have constant transmission parameters. For example, one or more STAs may indicate to an AP that their transmission parameters do not change, and the AP may broadcast an indication of the unchanging transmission parameters. For example, TX parameter IE <NUM> may include a number of reported STA field having one byte. The value of the number of reported STA field indicates the number of MAC address fields which follow, each MAC address field indicating an address of a corresponding STA whose transmission parameters do not change. The TX parameter IE <NUM> may be communicated in a broadcast, such as in a beacon or another broadcast by the AP. A device receiving the broadcast may determine that the STAs whose addresses are indicated in the MAC address fields have unchanging transmission parameters. Relative differences in CSI between subsequently received frames from one of the indicated STAs may be used for WiFi sensing measurements.

Note that the example implementations are not limited to the specific field formats of the TX parameter IE <NUM> and TX parameter IE <NUM>, but that the TX parameter IE may have any suitable field format for indicating the transmission parameters.

A wireless device communicating its own transmission parameters in a TX parameter IE, such as TX parameter IE <NUM>, may include the TX parameter IE in any of a number of suitable transmissions. For example, the TX parameter IE <NUM> may be included in a public frame of a data A-MPDU transmitted by the wireless device. For example, <FIG> shows an example format <NUM> for a data A-MPDU including a frame communicating a TX parameter IE, according to some example implementations. With respect to <FIG>, the A-MPDU may include a first A-MPDU delimiter <NUM>, a TX parameter MAC management protocol data unit (MMPDU) <NUM>, and one or more pairs of A-MPDU delimiters and data MPDUs, such as A-MPDU delimiter <NUM>/data MPDU <NUM> and A-MPDU delimiter <NUM>/data MPDU <NUM>. The TX parameter MMPDU <NUM> may be a public frame including the TX parameter IE, such as TX parameter IE <NUM>. An example frame format of the TX parameter MMPDU is described with respect to <FIG>.

In another aspect, the TX parameter IE may be included in a public frame included in a heading PPDU of an A-PPDU. For example, the heading PPDU may include the TX parameter MMPDU <NUM> described with respect to <FIG> shows an example format <NUM> for an A-PPDU communicating the TX parameter IE, according to some implementations. As shown in <FIG>, the A-PPDU may include an A-PPDU delimiter <NUM>, a PPDU <NUM> including the TX parameter MMPDU, and one or more pairs of A-PPDU delimiters and data PPDUs, such as A-PPDU delimiter <NUM>/data PPDU <NUM>, and A-PPDU delimiter <NUM>/data PPDU <NUM>.

In another aspect, the TX parameter IE may be transmitted as part of a transmission opportunity (TXOP) and may be transmitted in advance of data transmitted during the TXOP. For example, a TX parameter frame, such as the TX parameter MMPDU, may be transmitted in advance of an A-MPDU transmitted during the TXOP. <FIG> shows an example TXOP <NUM>, during which TX parameters may be communicated, according to some implementations. As shown in <FIG>, the TXOP <NUM> may begin with transmission of the TX parameter frame <NUM>, which may be the TX parameter MMPDU. A short delay, such as a reduced interframe space (RIFS) may follow before transmission of the A-MPDU <NUM>. In some aspects, the TX parameter frame <NUM> may be transmitted at a reduced MCS as compared to the MCS used for transmission of the A-MPDU <NUM>. This reduced MCS may be a basic MCS.

After the TX parameters are communicated for one or more wireless devices, for example using one or more frames including a TX parameter IE such as TX parameter IE <NUM> or <NUM>, the TX parameters may be used for WiFi sensing measurements for subsequent frames transmitted by the one or more wireless devices. For example, after receiving the A-MPDU <NUM> or A-PPDU from a transmitting device, a receiving device may determine the transmission parameters based on TX parameter MMPDU <NUM> or the PPDU <NUM> and use subsequent transmissions from the transmitting device for sensing measurements. Similarly, after receiving the TX parameter frame <NUM> from a transmitting device, a receiving device may determine the transmission parameters and use the PPDU containing the A-MPDU <NUM> for sensing measurements. Note that WiFi sensing measurements may be made based on the subsequent transmissions regardless of whether or not the subsequent transmissions are decoded. For example, the WiFi sensing measurements may be based on MPDUs of the A-MPDU <NUM> regardless of whether or not all the MPDUs in A-MPDU <NUM> are decoded.

In some implementations, it may be desirable to verify the integrity of frames used for exchanging transmission parameters, in order to reduce the risk of man-in-the-middle attacks on WiFi sensing systems. That is, if another device transmits one or more frames purporting to advertise transmission parameters for wireless sensing, it may be desirable to verify the integrity of those transmission parameters in order for accurate sensing measurements to be reliably performed. Accordingly, further aspects of the present disclosure provide methods and systems for verifying the integrity of transmission parameters communicated for wireless sensing.

Some known systems provide protection of multiply addressed management frames through authentication of the frame's payload. However, such solutions are not helpful for protecting transmission parameters for WiFi sensing, because they do not allow verification of the integrity of the receiving address (RA) or transmitting address (TA) of the frame. Such protection is important for WiFi sensing, as different transmitting devices (STAs or APs) may have differing transmission parameters, and even the same device may have changing transmission parameters.

Aspects of the present disclosure allow for verification of the integrity of TX parameters for WiFi sensing by appending a message integrity code (MIC) to the frames used for sending the TX parameters IE in such a way that third party receiving devices may verify the MIC sent by a transmitting device before using transmissions for sensing measurements.

More particularly, the example implementations may modify the broadcast/multicast integrity protocol (BIP) to provide an indication of the access category (AC) and traffic stream (TS) of the TXOP used for transmitting the TX parameters IE by adding a field to a management MIC element of the frame used for transmitting the TX parameters IE (for example, the TX parameter MMPDU <NUM>). Additionally, a new category of action frame may be defined to include the TX parameters IE and the management MIC element.

<FIG> shows an example frame format <NUM> for an authenticated TX parameters frame. The authenticated TX parameters frame is shown to include a MAC header <NUM>, a category field <NUM> indicating the category authenticated dual of public action, a public action field <NUM> indicating that the action frame is a TX parameters frame, a TX parameters IE <NUM>, a management MIC element <NUM>, and an FCS <NUM>. The category authenticated dual of public action allows the integrity provided by the management MIC element <NUM> to be applied to frames to be sent within and outside of the BSS to which a transmitting device is associated. The TX parameters frame is a frame type belonging to the category authenticated dual of public action. shows an example frame format <NUM> for a management MIC element. For example, the frame format <NUM> may be a frame format for the management MIC element <NUM> of <FIG>. The frame format <NUM> includes an element ID field <NUM> indicating the ID of the management MIC element, a length field <NUM> indicating length of the management MIC element, an AC/TS field <NUM> indicating the AC/TS of the authenticated TX parameters frame, a Key ID field <NUM> indicating one or more keys associated with calculation of the MIC, a PN field <NUM> indicating a packet number of the authenticated TX parameters frame, and a MIC field <NUM> indicating the MIC of the authenticated TX parameters frame.

In addition, providing integrity protection for the AC/TS, for example by including the AC/TS field <NUM> in the management MIC element, as shown with respect to <FIG>, may be desirable for legacy devices to benefit from the protection of the TX parameters. More particularly, some legacy devices may not be able to perform packet number (PN) generation and MIC-related integrity calculations in legacy hardware (HW). In some aspects, the MIC calculation may be performed by software (SW), while the TX parameters frame may be delivered to the legacy device's HW through regular data frames flow. These data frames may be organized and send in separate queues per AC/TS. Thus, while the TX parameters frame is generated by the SW, including the MIC calculation, the actual order of transmission is not yet known, for example due to the priority quality of service access to the wireless medium. Accordingly, some PNs generated by the SW may be sent and received out of order, particularly when generated as a single sequence. Accordingly, in some aspects, PNs may be generated separately for each AC/TS queue, and the AC/TS field <NUM> thus indicates to which sequence of PNs the PN in the PN field <NUM> belongs. This may allow protection of the TX parameters frame even for legacy devices.

<FIG> shows a flowchart illustrating an example operation <NUM> for wireless communication that supports sessionless wireless sensing. In some implementations, the operation <NUM> may be performed by a wireless communication device operating as or within an AP, such the AP <NUM> of <FIG>, the wireless communication device <NUM> of <FIG> or the AP <NUM> of <FIG>. In some other implementations, the operation <NUM> may be performed by a wireless communication device operating as or within a STA, such as the STA <NUM> of <FIG>, the wireless communication device <NUM> of <FIG>, or the STA <NUM> of <FIG>.

For example, at block <NUM>, the wireless communication device <NUM> receives a first wireless transmission including a transmission (TX) parameter information element (IE). At block <NUM>, the wireless communication device <NUM> obtains one or more transmission parameters for one or more second wireless communication devices associated with the TX parameter IE. At block <NUM>, the wireless communication device <NUM> receives a second wireless transmission from one of the one or more second wireless communication devices. At block <NUM>, the wireless communication device <NUM> obtains one or more wireless sensing measurements associated with the second wireless transmission and the one or more transmission parameters.

In some implementations, the wireless communication device <NUM> further verifies an integrity of the TX parameter IE associated with a message integrity code (MIC) in the first wireless transmission. In some aspects, the MIC is configured to verify an integrity of at least an access category (AC), or traffic stream (TS field) associated with the first wireless transmission.

In some aspects, the first wireless transmission is received from an access point (AP), and the TX parameter IE indicates that each of the at least one second wireless communication devices have static transmission parameters. In some aspects, the first wireless transmission is a broadcast transmission.

In some aspects, the first wireless transmission includes a frame received from a station (STA), and the second wireless transmission is received from the STA. In some aspects, the frame is included in an aggregated media access control (MAC) protocol data unit (A-MPDU). In some aspects, the frame is included in an initial physical layer (PHY) protocol data unit (PPDU) of an aggregated PPDU (A-PPDU). In some aspects, the frame is a public frame transmitted at a basic modulation and coding scheme (MCS).

In some aspects, the TX parameter IE is received with each transmission received from the STA. In some aspects, the TX parameter IE is received periodically from the STA.

In some aspects, the TX parameter IE indicates a transmit power of the STA. In some aspects the TX parameter IE indicates one or more of changes in multiple-input multiple-output (MIMO) precoding used by the STA and changes in beamforming and antenna selection settings used by the STA. In some aspects an index in the TX parameter IE indicates changes in the MIMO precoding or beamforming and antenna selection settings used by the STA.

In some aspects, the TX parameters IE indicates whether or not the STA has moved since the STA transmitted a previous frame including a TX parameter IE.

<FIG> shows a flowchart illustrating an example operation <NUM> for wireless communications that supports sessionless wireless sensing. In some implementations, the operation <NUM> may be performed by a wireless communication device operating as or within an AP, such the AP <NUM> of <FIG>, the wireless communication device <NUM> of <FIG> or the AP <NUM> of <FIG>. In some other implementations, the operation <NUM> may be performed by a wireless communication device operating as or within a STA, such as the STA <NUM> of <FIG>, the wireless communication device <NUM> of <FIG>, or the STA <NUM> of <FIG>.

For example, at block <NUM>, the wireless communication device <NUM> receives a first wireless transmission including a TX parameter IE. At block <NUM>, in response to a message integrity code (MIC) in the first wireless transmission not verifying an integrity of the TX parameter IE, the wireless communication device <NUM> discards the first wireless transmission. In block <NUM>, in response to the MIC verifying the integrity of the TX parameter IE, the wireless communication device <NUM> obtains one or more transmission parameters for one or more second wireless communication devices associated with the TX parameter IE (<NUM>), receives a second wireless transmission from one of the one or more second wireless communication devices (<NUM>), and obtains one or more wireless sensing measurements associated with the second wireless transmission and the one or more transmission parameters (<NUM>).

In some aspects, the MIC is configured to verify an integrity of at least an access category (AC), or traffic stream (TS field) associated with the first wireless transmission.

The term "determining" encompasses a wide variety of actions and, therefore, "determining" can include calculating, computing, processing, deriving, investigating, looking up (such as via looking up in a table, a database, or another data structure), ascertaining and the like. Also, "determining" can include receiving (such as receiving information), accessing (such as accessing data in a memory) and the like. Also, "determining" can include resolving, selecting, choosing, establishing and other such similar actions.

The various illustrative logics, logical blocks, modules, circuits, and algorithm processes described in connection with the implementations disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. The interchangeability of hardware and software has been described generally, in terms of functionality, and illustrated in the various illustrative components, blocks, modules, circuits and processes described herein.

The hardware and data processing apparatus used to implement the various illustrative logics, logical blocks, modules and circuits described in connection with the aspects disclosed herein may be implemented or performed with a general purpose single- or multi-chip processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, or any conventional processor, controller, microcontroller, or state machine. A processor also may be implemented as a combination of computing devices such as, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. In some implementations, particular processes and methods may be performed by circuitry that is specific to a given function.

Claim 1:
A first wireless communication device (<NUM>; <NUM>; <NUM>; <NUM>; <NUM>), comprising:
an interface configured to:
receive a first wireless transmission, the first wireless transmission including a transmit, TX, parameter information element, IE; and
receive a second wireless transmission; and
a processing system configured to:
obtain one or more transmission parameters for one or more second wireless communication devices associated with the TX parameter IE, wherein the second wireless transmission is from one of the one or more second wireless communication devices; and
obtain one or more wireless sensing measurements associated with the second wireless transmission and the one or more transmission parameters.