Unilateral round trip time (RTT) localization estimation

Abstract

The invention provides a method, a device and a system for performing single-side ranging operation. In some implementations, a first device transmits a first frame to a wireless station (STA), and receives a second frame responsive to the first frame from the STA. The first device obtains information indicating a time period between the first device transmitting the first frame and receiving the second frame, and obtains information indicating time delays associated with a plurality of second devices, wherein each of the time delays is between a respective reception of the first frame and the second frame by a respective one of the second devices. The first device obtains a location of the STA based on the time period, the time delay associated with the plurality of second devices, and a signal propagation time between the first device and each of the plurality of second devices.

Description

[0001] Cross-references

[0002] This patent application claims the benefit of U.S. patent application No. 17 / 844,390, entitled “SINGLE-SIDED ROUND TRIP TIME (RTT) LOCATION ESTIMATION,” filed by CHO et al. on June 20, 2022, which is assigned to the assignee of this application. Technical Field

[0003] The present disclosure relates generally to wireless communications and, more particularly, to estimating the location of a wireless device. Background Art

[0004] 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 several client devices, also referred to as stations (STAs). The basic building block of a WLAN that complies with the Institute of Electrical and Electronics Engineers (IEEE) 802.11 family of standards is a basic service set (BSS) managed by an AP. Each BSS is identified by a basic service set identifier (BSSID) announced by the AP. The AP periodically broadcasts beacon frames to enable any STA within the wireless range of the AP to establish or maintain a communication link with the WLAN.

[0005] The continued growth of APs and WLANs has made it possible for positioning systems to use these APs for position determination, especially in areas where there are a large number of active APs (such as urban cores, shopping malls, office buildings, sports venues, etc.). For example, a wireless device such as a mobile phone or tablet computer can use the round-trip time (RTT) of a signal exchanged with an AP to determine the distance between the wireless device and the AP. Once the distance between the wireless device and three APs with known locations is determined, the location of the wireless device can be determined using trilateration techniques.

[0006] As ranging operations become increasingly important for determining the location of wireless devices, there is a need to improve the accuracy of ranging operations. Summary of the invention

[0007] The systems, methods, and devices of the disclosure each have several innovative aspects, no single one of which is solely responsible for the desirable attributes disclosed herein.

[0008] An innovative aspect of the subject matter described in the present disclosure may be implemented in a first device. The first device may include: at least one processor; and at least one memory, the at least one memory being communicatively coupled to the at least one processor. In some specific implementations, the at least one memory stores processor-readable code, which when executed by the at least one processor is configured to: send a first frame to a wireless station (STA); and receive a second frame from the STA, the second frame being in response to the first frame. Execution of the processor-readable code is configured to: obtain information indicating a time period between the first device sending the first frame and the first device receiving the second frame; and obtain information indicating time delays associated with a plurality of second devices, wherein each of the time delays is between the respective reception of the first frame and the second frame by a respective second device in the plurality of second devices. Execution of the processor-readable code is configured to: obtain the position of the STA based on the time period, the time delay associated with the plurality of second devices, and the signal propagation time between the first device and each of the plurality of second devices. In some specific implementations, execution of the processor readable code may also be configured to: in response to the location of the STA being within the area or structure, enable one or more services for the STA; or in response to the location of the STA being outside the area or the structure, disable the one or more services for the STA.

[0009] In some instances, the first frame may be a quality of service (QoS) null frame or a ready to send (RTS) frame, and the second frame may be an acknowledgement (ACK) frame in response to the QoS null frame or a clear to send (CTS) frame in response to the RTS frame. In some other instances, the first frame may be one of a single user (SU) physical layer protocol data unit (PPDU) or a multi-user (MU) PPDU sent over the entire bandwidth of a wireless channel, and the second frame may be an acknowledgement (ACK) frame or a block ACK (BA) frame received over the entire bandwidth of the wireless channel.

[0010] In various specific implementations, the position of the STA may be obtained independently of a time period or time delay associated with the STA. In some instances, the time period may be associated with the end of the transmission of the first frame and the beginning of the reception of the second frame, and each of the time delays may be associated with the end of the reception of the first frame and the beginning of the reception of the second frame by the corresponding second device among the multiple second devices. In some other instances, the time period may be equal to the sum of the signal propagation time from the first device to the STA, the short interframe space (SIFS) duration associated with the STA, and the signal propagation time from the STA to the first device. In some aspects, the corresponding time delay associated with the corresponding second device may be equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the corresponding second device minus the signal propagation time from the first device to the second device.

[0011] In some specific implementations, executing the processor-readable code to obtain the position of the STA may be configured to: obtain a first relationship between the time period and the difference between the coordinates of the STA and the coordinates of the first device. Executing the processor-readable code to obtain the position of the STA may also be configured to: for each second device in the plurality of second devices, obtain a second relationship between the corresponding time delay associated with the corresponding second device and the difference between the coordinates of the STA and the coordinates of the corresponding second device. Executing the processor-readable code to obtain the position of the STA may also be configured to: obtain the coordinates of the plurality of second devices; and obtain the coordinates of the STA based on the trilateral measurement of the first relationship and the plurality of corresponding second relationships. In various aspects, executing the processor-readable code may also be configured to: for each corresponding second device in the plurality of second devices, obtain the coordinates of the STA based on the trilateral measurement of the first relationship and the second relationship. Executing the processor-readable code may also be configured to: send an indication of the SIFS duration to the STA.

[0012] In some specific implementations, the first device may be a first access point (AP) associated with the STA, and the plurality of second devices may be a plurality of corresponding passive listening devices not associated with the STA. In some instances, execution of the processor-readable code may also be configured to: receive a third frame from each of the plurality of second devices, the third frame indicating the time delay associated with the corresponding second device. In some other specific implementations, one or both of the information indicating the time delay associated with the plurality of second devices or the position of the STA may be obtained from a network entity. In some instances, execution of the processor-readable code may also be configured to: obtain from the network entity the coordinates of the STA relative to the coordinates of the first device.

[0013] In some specific implementations, execution of the processor readable code may also be configured to: assign a sequence number to the first frame; send an indication of the sequence number to each of the plurality of second devices; and send instructions to each of the plurality of second devices for reporting the time of arrival (TOA) timestamps of all first frames carrying the indicated sequence number and reporting the TOA timestamps of all second frames responsive to the first frame. In some other specific implementations, execution of the processor readable code may also be configured to: embed a signal or value within the first frame; send an indication of the signal or the value to each of the plurality of second devices; and send instructions to each of the plurality of second devices for reporting the TOA timestamps of all first frames carrying the embedded signal or value and reporting the TOA timestamps of all second frames responsive to the first frame carrying the embedded signal or value. In some aspects, the embedded signal or value may be indicated by one of reserved or unused bits of a preamble of the first frame, reserved or unused bits of a medium access control (MAC) header of the first frame, or reserved or unused bits of an element, field, or subfield following the MAC header of the first frame.

[0014] Another innovative aspect of the subject matter described in the present disclosure may be implemented as a method for wireless communication by a first device. In some specific implementations, the method includes: sending a first frame to a STA; and receiving a second frame from the STA, the second frame responding to the first frame. The method includes: obtaining information indicating a time period between the first device sending the first frame and the first device receiving the second frame; and obtaining information indicating time delays associated with multiple second devices, wherein each of the time delays is between the corresponding reception of the first frame and the second frame by a corresponding second device in the multiple second devices. The method includes: obtaining the location of the STA based on the time period, the time delay associated with the multiple second devices, and the signal propagation time between the first device and each of the multiple second devices. In some specific implementations, the method may also include: enabling one or more services for the STA in response to the location of the STA being within an area or structure; or disabling the one or more services for the STA in response to the location of the STA being outside the area or structure.

[0015] In some instances, the first frame may be a QoS null frame or an RTS frame, and the second frame may be an ACK frame in response to the QoS null frame or a CTS frame in response to the RTS frame. In some other instances, the first frame may be one of a SU PPDU or an MU PPDU sent over the entire bandwidth of a wireless channel, and the second frame may be an ACK frame or a BA frame received over the entire bandwidth of the wireless channel.

[0016] In various specific implementations, the position of the STA may be obtained independently of a time period or time delay associated with the STA. In some instances, the time period may be associated with the end of the transmission of the first frame and the beginning of the reception of the second frame, and each of the time delays may be associated with the end of the reception of the first frame and the beginning of the reception of the second frame by the corresponding second device among the multiple second devices. In some other instances, the time period may be equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the first device. In some aspects, the corresponding time delay associated with the corresponding second device may be equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the corresponding second device minus the signal propagation time from the first device to the second device.

[0017] In some specific implementations, obtaining the position of the STA may include: obtaining a first relationship between the time period and the difference between the coordinates of the STA and the coordinates of the first device. Obtaining the position of the STA may include: for each second device in the plurality of second devices, obtaining a second relationship between the corresponding time delay associated with the corresponding second device and the difference between the coordinates of the STA and the coordinates of the corresponding second device. Obtaining the position of the STA may include: obtaining the coordinates of the plurality of second devices; and obtaining the coordinates of the STA based on trilateral measurements of the first relationship and the plurality of corresponding second relationships. In various aspects, the method may also include: for each corresponding second device in the plurality of second devices, obtaining the coordinates of the STA based on trilateral measurements of the first relationship and the second relationship; and sending an indication of the SIFS duration to the STA.

[0018] In some specific implementations, the first device may be a first AP associated with the STA, and the plurality of second devices may be a plurality of corresponding passive listening devices not associated with the STA. In some instances, the method may further include: receiving a third frame from each of the plurality of second devices, the third frame indicating the time delay associated with the corresponding second device. In some other specific implementations, one or both of the information indicating the time delay associated with the plurality of second devices or the position of the STA may be obtained from a network entity. In some instances, the method may further include: obtaining from the network entity the coordinates of the STA relative to the coordinates of the first device.

[0019] In some specific implementations, the method may also include: assigning a sequence number to the first frame; sending an indication of the sequence number to each of the plurality of second devices; and sending an instruction to each of the plurality of second devices to report the TOA timestamps of all first frames carrying the indicated sequence number and to report the TOA timestamps of all second frames responsive to the first frame. In some other specific implementations, the method may also include: embedding a signal or value within the first frame; sending an indication of the signal or the value to each of the plurality of second devices; and sending an instruction to each of the plurality of second devices to report the TOA timestamps of all first frames carrying the embedded signal or value and to report the TOA timestamps of all second frames responsive to the first frame carrying the embedded signal or value. In some aspects, the embedded signal or value may be indicated by one of a reserved or unused bit of a preamble of the first frame, a reserved or unused bit of a MAC header of the first frame, or a reserved or unused bit of an element, field, or subfield following the MAC header of the first frame.

[0020] Another innovative aspect of the subject matter described in the present disclosure may be implemented as a method for wireless communication by an apparatus. The apparatus may include: a component for sending a first frame to a wireless station (STA); a component for receiving a second frame from the STA, the second frame being responsive to the first frame; and a component for obtaining information indicating a time period between the apparatus sending the first frame and the apparatus receiving the second frame. The apparatus may include: a component for obtaining information indicating time delays associated with a plurality of second devices, wherein each of the time delays is between respective receptions of the first frame and the second frame by respective second devices in the plurality of second devices. The apparatus may include: a component for obtaining a position of the STA based on the time period, the time delays associated with the plurality of second devices, and a signal propagation time between the apparatus and each of the plurality of second devices.

[0021] Another innovative aspect of the subject matter described in the present disclosure may be implemented in a non-transitory computer-readable storage medium. The non-transitory computer-readable storage medium stores processor-readable code that, when executed by one or more processors of a device, causes the device to perform operations. In some specific implementations, the operation may include: sending a first frame to a wireless station (STA); receiving a second frame from the STA, the second frame responding to the first frame; and obtaining information indicating a time period between the device sending the first frame and the device receiving the second frame. The operation may include: obtaining information indicating time delays associated with a plurality of second devices, wherein each of the time delays is between the respective reception of the first frame and the second frame by a respective second device in the plurality of second devices. The operation may include: obtaining the position of the STA based on the time period, the time delay associated with the plurality of second devices, and the signal propagation time between the device and each of the plurality of second devices.

[0022] The details of one or more specific implementations of the subject matter described in this disclosure are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A schematic diagram of an example wireless communication network is shown.

[0024] Figure 2A Example protocol data units (PDUs) that can be used for communications between an access point (AP) and one or more wireless stations (STAs) are shown.

[0025] Figure 2B Shows Figure 2A Example fields in a PDU.

[0026] Figure 3A Another example PDU that can be used for communication between an AP and one or more STAs is shown.

[0027] Figure 3B Another example PDU that can be used for communication between an AP and one or more STAs is shown.

[0028] Figure 4 An example physical layer convergence protocol (PLCP) protocol data unit (PPDU) that can be used for communication between an AP and several STAs is shown.

[0029] Figure 5 A block diagram of an example wireless communication device is shown.

[0030] Fig. 6A A block diagram of an example access point (AP) is shown.

[0031] Figure 6B A block diagram of an example station (STA) is shown.

[0032] Figure 7 A schematic diagram of another example wireless network is shown.

[0033] Figure 8 A timing diagram of an example wireless communication supporting single-sided ranging operations is shown.

[0034] Fig. 9 A timing diagram of another example wireless communication supporting single-sided ranging operation is shown.

[0035] Fig. 10A An illustration depicting an example 2-dimensional positioning of a wireless device is shown.

[0036] Fig. 10B An illustration depicting an example 3-dimensional positioning of a wireless device is shown.

[0037] Figures 11 to 16 A flow diagram illustrating example operations for wireless communications supporting single-sided ranging operations is shown.

[0038] Fig.17 A block diagram of an example wireless communication device is shown in accordance with some implementations.

[0039] The same reference numbers and designations in different drawings indicate similar elements. DETAILED DESCRIPTION

[0040] The following description is directed to some specific implementations in order to describe the innovative aspects of the present disclosure. However, one of ordinary skill in the art will readily recognize that the teachings herein can be applied in a variety of different ways. The described implementations can be implemented in any device, system, or network capable of sending and receiving radio frequency (RF) signals according to one or more of the following: Long Term Evolution (LTE), 3G, 4G, or 5G (New Radio (NR)) standards promulgated by the 3rd Generation Partnership Project (3GPP), the Institute of Electrical and Electronics Engineers (IEEE) 802.11 standard, the IEEE 802.15 standard, or as defined by the Bluetooth Special Interest Group (SIG). Standards, etc. The described implementations may be implemented in any device, system, or network capable of sending 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 may also be implemented using other wireless communication protocols or RF signals suitable for use in one or more of a wireless wide area network (WWAN), a wireless personal area network (WPAN), a wireless local area network (WLAN), or an Internet of Things (IOT) network.

[0041] The distance between a pair of devices can be determined using the round trip time (RTT) of a signal exchanged between the pair of devices. The distance (d) between the first device and the second device can be expressed as d=c*RTT / 2, where c is the speed of light, and RTT is the sum of the signal propagation time of the first frame sent from the first device to the second device and the signal propagation time of the second frame sent from the second device to the first device. Specifically, the value of RTT may be equal to the time difference between the departure time (TOD) of the first frame from the first device and the arrival time (TOA) of the second frame at the first device minus the time delay between the reception of the first frame at the second device and the transmission of the second frame by the second device. The time delay that may be associated with the second device switching from a receive mode to a transmit mode may be a short interframe space (SIFS) duration.

[0042] Due to the process variations inherent in semiconductor manufacturing technology that cause clock drift, the time delay and SIFS duration may vary from wireless device to wireless device, especially from different manufacturers and models of wireless devices. In this way, the SIFS duration associated with the second device is usually estimated, which may lead to unacceptable ranging errors. For example, although the IEEE 802.11 family of wireless communication standards specifies the SIFS duration as 10 microseconds (μs) and has a tolerance of ±900 nanoseconds (ns) for signals sent in the 2.4GHz band, a SIFS estimation error of only ±25ns may result in a ranging error of ±7.5 meters, which may be unacceptable for many indoor positioning applications.

[0043] Although the Fine Timing Measurement (FTM) protocol defined in the 802.11REVmc, 11REVmd, 11REVme, and 11ax amendments to the IEEE 802.11 standard allows RTT values ​​to be obtained without estimating SIFS, the FTM protocol involves exchanging 6 or more frames between ranging devices, which may increase congestion and latency on the shared wireless medium. In addition, many wireless devices do not support the FTM protocol or the RTT ranging procedures described in the IEEE 802.11 standard and are therefore unable to participate in such ranging operations.

[0044] Various specific implementations are generally related to positioning in a wireless network, and specifically to a unilateral RTT operation that can use two frame transmissions to measure the distance of a STA without estimating the SIFS duration of the STA, and regardless of whether the STA supports any standard-based ranging procedures (such as FTM protocols). In some specific implementations, a first device can send a first frame to a STA via a wireless medium. The STA receives the first frame and sends a second frame in response to the first frame to the first device. The first device can obtain information indicating a time period between sending the first frame and receiving the second frame. In some instances, the first device can also obtain information indicating time delays associated with multiple second devices, wherein each of the indicated time delays is between the corresponding reception of the first frame and the second frame by a corresponding second device in the second device. In some specific implementations, the position of the STA can be obtained based on the time period, the time delay associated with the multiple second devices, and the signal propagation time between the first device and each of the multiple second devices. In some aspects, the position of the STA can be obtained independently of the time period, time delay, or other measurement results associated with the STA.

[0045] Specific implementations of the subject matter described in the present disclosure may be implemented to achieve one or more of the following potential advantages. By obtaining the position of a STA based on two frame transmissions as described above and throughout the present application (e.g., without estimating SIFS), the accuracy of the ranging operation can be improved because the position of the STA obtained is independent of the uncertainty and timing error associated with estimating SIFS. Additionally or alternatively, the position of the STA can be obtained while minimizing the overhead, congestion, and latency associated with the ranging operation. For example, compared to the FTM protocol involving the exchange of 6 or more frames between ranging devices, the technique of using two frame transmissions to obtain the positioning of the STA can reduce communications on the network. In addition, the ability to use two frame exchanges to measure the distance of STAs that do not support standard-based positioning procedures can be used to provide a more complete mapping of STAs located in or passing through a specific area or structure (compared to only obtaining the positions of those STAs that support standard-based positioning procedures).

[0046] Figure 1 A block diagram of an example wireless communication network 100 is shown. According to some aspects, the wireless communication network 100 may be an example of a wireless local area network (WLAN) such as a Wi-Fi network (and will be referred to as WLAN 100 hereinafter). For example, the WLAN 100 may be a network that implements at least one of the IEEE 802.11 family of standards such as those defined by the IEEE 802.11-2016 specification or amendments thereof, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be. The WLAN 100 may include numerous wireless communication devices such as an access point (AP) 102 and a plurality of stations (STAs) 104. Although only one AP 102 is shown, the WLAN 100 may also include a plurality of APs 102.

[0047] Each STA 104 may also 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, etc. STA 104 may represent a variety of devices, such as mobile phones, personal digital assistants (PDAs), other handheld devices, netbooks, notebook computers, tablet computers, laptops, display devices (e.g., TVs, computer monitors, navigation systems, etc.), music or other audio or stereo equipment, remote control devices (“remote controls”), printers, kitchen or other home appliances, key fobs (e.g., for passive keyless entry and start (PKES) systems), etc.

[0048] A single AP 102 and the associated set of STAs 104 may be referred to as a basic service set (BSS), which is managed by the corresponding AP 102 . Figure 1Additionally shown is an example coverage area 106 of the AP 102, which may represent a basic service area (BSA) of the WLAN 100. The BSS may be identified to users by a service set identifier (SSID) and to other devices by a basic service set identifier (BSSID), which may be a medium access control (MAC) address of the AP 102. The AP 102 periodically broadcasts a beacon frame (“beacon”) including the BSSID to enable any STA 104 within the wireless range of the AP 102 to “associate” or re-associate with the AP 102, thereby establishing a corresponding communication link 108 (hereinafter also referred to as a “Wi-Fi link”) with the AP 102 or maintaining a communication link 108 with the AP 102. For example, the beacon may include an identification of a primary channel used by the corresponding AP 102 and a timing synchronization function for establishing or maintaining timing synchronization with the AP 102. The AP 102 may provide access to external networks to various STAs 104 in the WLAN via the corresponding communication links 108.

[0049] To establish a communication link 108 with the AP 102, each of the STAs 104 is configured to perform passive or active scanning operations ("scans") on frequency channels in one or more frequency bands (eg, the 2.4 GHz, 5.0 GHz, 6.0 GHz, or 60 GHz bands). To perform passive scanning, the STA 104 listens for beacons transmitted by the corresponding AP 102 at periodic time intervals, referred to as target beacon transmission times (TBTTs), measured in time units (TUs), where one TU may be equal to 1024 microseconds (μs). To perform active scanning, the STA 104 generates probe requests and sequentially transmits these probe requests on each channel to be scanned, and listens for probe responses from the AP 102. Each STA 104 may be configured to identify or select an AP 102 to associate with based on the scanning information obtained through passive or active scanning, and perform authentication and association operations to establish a communication link 108 with the selected AP 102. The AP 102 assigns an association identifier (AID) to the STA 104 at the end of the association operation, and the AP 102 uses the association identifier (AID) to track the STA 104.

[0050] As wireless networks become more and more common, STA 104 may have the opportunity to select one of many BSSs within the range of the STA or to select among multiple APs 102 that together form an extended service set (ESS) (including multiple connected BSSs). Extended network stations associated with WLAN 100 may be connected to a wired or wireless distribution system that allows multiple APs 102 to be connected in such ESS. In this way, STA 104 may be covered by more than one AP 102 and may be associated with different APs 102 at different times for different transmissions. Additionally, after associating with AP 102, STA 104 may also be configured to periodically scan its surroundings to find a more appropriate AP 102 to associate with. For example, a STA 104 that is moving relative to its associated AP 102 may perform a "roaming" scan to find another AP 102 with more suitable network characteristics (such as a larger received signal strength indicator (RSSI) or a reduced traffic load).

[0051] In some cases, STA 104 may form a network without AP 102 or other equipment other than STA 104 itself. An example of such a network is a self-organizing (ad hoc) network (or wireless self-organizing network). A self-organizing network may alternatively be referred to as a mesh network or a peer-to-peer (P2P) network. In some cases, a self-organizing network may be implemented within a larger wireless network (such as WLAN 100). In such a specific implementation, although STA 104 may be able to communicate with each other through AP 102 using communication link 108, STA 104 may also communicate directly with each other via direct communication link 110. Additionally, two STA 104 may communicate via direct communication link 110, regardless of whether the two STA 104 are associated with the same AP 102 and served by the same AP. In such a self-organizing system, one or more STA 104 may assume the role played by AP 102 in the BSS. Such STA 104 may be referred to as a group owner (GO) and may coordinate the transmission within the self-organizing network. Examples of direct communication link 110 include a Wi-Fi direct connection, a connection established by using a Wi-Fi Tunneled Direct Link Setup (TDLS) link, and other P2P group connections.

[0052] The AP 102 and the STA 104 may operate and communicate in accordance with the IEEE 802.11 family of standards (such as those defined by the IEEE 802.11-2016 specification or amendments thereof, including, but not limited to, 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be) (via respective communication links 108). These standards define WLAN radio and baseband protocols for the PHY and medium access control (MAC) layers. The AP 102 and the STA 104 send and receive wireless communications (hereinafter also referred to as "Wi-Fi communications") to and from each other in the form of physical layer convergence protocol (PLCP) protocol data units (PPDUs). The AP 102 and STA 104 in the WLAN 100 may send PPDUs on an unlicensed spectrum, which may be a portion of a spectrum that includes frequency bands traditionally used by Wi-Fi technology, such as the 2.4 GHz band, the 5.0 GHz band, the 60 GHz band, the 3.6 GHz band, and the 900 MHz band. Some implementations of the AP 102 and STA 104 described herein may also communicate in other frequency bands, such as the 6.0 GHz band, that may support both licensed and unlicensed communications. The AP 102 and STA 104 may also be configured to communicate on other frequency bands, such as shared licensed frequency bands, where multiple operators may have licenses to operate in one or more of the same or overlapping frequency bands.

[0053] Each of the frequency bands may include multiple sub-bands or frequency channels. For example, PPDUs that comply with the IEEE 802.11n, 802.11ac, and 802.11ax standard amendments may be sent on 2.4 GHz and 5.0 GHz frequency bands, where each frequency band is divided into multiple 20 MHz channels. In this way, these PPDUs are sent on a physical channel with a minimum bandwidth of 20 MHz, but larger channels may be formed through channel bonding. For example, a PPDU may be sent on a physical channel with a bandwidth of 40 MHz, 80 MHz, 160 MHz, or 320 MHz by bonding multiple 20 MHz channels together.

[0054] Each PPDU is a composite structure including a PHY preamble and a payload in the form of a PLCP service data unit (PSDU). The information provided in the preamble can be used by the receiving device to decode subsequent data in the PSDU. In an instance where the PPDU is sent on a bound channel, the preamble field can be copied and sent in each of a plurality of component channels. The PHY preamble may include both a legacy part (or "legacy preamble") and a non-legacy part (or "non-legacy preamble"). Legacy preambles can be used for packet detection, automatic gain control, and channel estimation, among other purposes. Legacy preambles can also generally be used to maintain compatibility with legacy devices. The format, decoding, and information provided therein of the non-legacy part of the preamble are based on the specific IEEE 802.11 protocol to be used to send the payload.

[0055] Figure 2A An example protocol data unit (PDU) 200 that can be used for wireless communication between an AP 102 and one or more STAs 104 is shown. For example, the PDU 200 can be configured as a PPDU. As shown, the PDU 200 includes a PHY preamble 202 and a payload 204. For example, the preamble 202 can include a legacy portion, which itself includes a legacy short training field (L-STF) 206 that can consist of two BPSK symbols, a legacy long training field (L-LTF) 208 that can consist of two BPSK symbols, and a legacy signal field (L-SIG) 210 that can consist of two BPSK symbols. The legacy portion of the preamble 202 can be configured according to the IEEE 802.11a wireless communication protocol standard. The preamble 202 may also include a non-legacy portion including one or more non-legacy fields 212 that comply with, for example, an IEEE wireless communication protocol, such as IEEE 802.11ac, 802.11ax, 802.11be, or a later wireless communication protocol.

[0056] L-STF 206 generally enables the receiving device to perform automatic gain control (AGC) and coarse timing and frequency estimation. L-LTF 208 generally enables the receiving device to perform fine timing and frequency estimation, and can also perform initial estimation of the wireless channel. L-SIG 210 generally enables the receiving device to determine the duration of the PDU and use the determined duration to avoid sending over the PDU. For example, L-STF 206, L-LTF 208 and L-SIG 210 can be modulated according to a binary phase shift keying (BPSK) modulation scheme. Payload 204 can be modulated according to a BPSK modulation scheme, an orthogonal BPSK (Q-BPSK) modulation scheme, an orthogonal amplitude modulation (QAM) modulation scheme, or another appropriate modulation scheme. Payload 204 may include a PSDU including a data field (DATA) 214, which in turn may carry, for example, a medium access control (MAC) protocol data unit (MPDU) or higher layer data in the form of an aggregated MPDU (A-MPDU).

[0057] Figure 2B Shows Figure 2A 2. Example L-SIG 210 in PDU 200 of FIG. L-SIG 210 includes a data rate field 222, a reserved bit 224, a length field 226, a parity bit 228, and a tail field 230. The data rate field 222 indicates the data rate (note that the data rate indicated in the data rate field 222 may not be the actual data rate of the data carried in the payload 204). The length field 226 indicates the packet length, for example, in symbols or bytes. The parity bit 228 can be used to detect bit errors. The tail field 230 includes a tail bit that can be used by a receiving device to terminate the operation of a decoder (e.g., a Viterbi decoder). The receiving device can use the data rate and length indicated in the data rate field 222 and the length field 226 to determine the packet duration, for example, in microseconds (μs) or other time units.

[0058] Figure 3A Another example PDU 300 that can be used for wireless communication between an AP and one or more STAs is shown. The PDU 300 can be used for SU, OFDMA, or MU-MIMO transmissions. The PDU 300 can be formatted as a high-efficiency (HE) WLAN PPDU according to the IEEE 802.11ax amendment to the IEEE 802.11 wireless communication protocol standard. The PDU 300 includes a PHY preamble that includes a legacy portion 302 and a non-legacy portion 304. The PDU 300 may also include a payload 306 after the preamble (e.g., in the form of a PSDU including a data field 324).

[0059] The legacy portion 302 of the preamble includes an L-STF 308, an L-LTF 310, and an L-SIG 312. The non-legacy portion 304 includes a repetition of the L-SIG (RL-SIG) 314, a first HE signal field (HE-SIG-A) 316, an HE short training field (HE-STF) 320, and one or more HE long training fields (or symbols) (HE-LTF) 322. For OFDMA or MU-MIMO communications, the non-legacy portion 304 also includes a second HE signal field (HE-SIG-B) 318 that is encoded separately from the HE-SIG-A 316. As with the L-STF 308, L-LTF 310, and L-SIG 312, in instances involving the use of bonded channels, the information in the RL-SIG 314 and HE-SIG-A 316 may be replicated and sent in each component 20 MHz channel. In contrast, the content in the HE-SIG-B 318 may be unique to each 20 MHz channel and targeted specific STA 104 .

[0060] The RL-SIG 314 may indicate to the HE-compatible STA 104 that the PDU 300 is a HE PPDU. The AP 102 may use the HE-SIG-A 316 to identify multiple STAs 104 and inform the multiple STAs that the AP has scheduled UL or DL ​​resources for them. For example, the HE-SIG-A 316 may include a resource allocation subfield indicating resource allocation for the identified STA 104. The HE-SIG-A 316 may be decoded by each HE-compatible STA 104 served by the AP 102. For MU transmission, the HE-SIG-A 316 also includes information that can be used by each identified STA 104 to decode the associated HE-SIG-B 318. For example, the HE-SIG-A 316 may indicate the frame format (including the positioning and length of the HE-SIG-B 318), the available channel bandwidth, and the modulation and coding scheme (MCS), among other examples. The HE-SIG-A 316 may also include HE WLAN signaling information that can be used by STAs 104 other than the identified STA 104.

[0061] HE-SIG-B 318 may carry STA-specific scheduling information, such as, for example, STA-specific (or "user-specific") MCS values ​​and STA-specific RU allocation information. In the context of DL MU-OFDMA, such information enables the corresponding STA 104 to identify and decode the corresponding resource unit (RU) in the associated data field 324. Each HE-SIG-B 318 includes a common field and at least one STA-specific field. The common field may indicate RU allocations (including RU assignments in the frequency domain) to multiple STAs 104, indicating which RUs are allocated for MU-MIMO transmissions and which RUs correspond to MU-OFDMA transmissions, as well as the number of users in the allocation and other examples. The common field may be encoded with common bits, CRC bits, and tail bits. User-specific fields are assigned to a specific STA 104 and may be used to schedule a specific RU and indicate the scheduling to other WLAN devices. Each user-specific field may include multiple user block fields. Each user block field may include two user fields containing information for two corresponding STAs to decode their corresponding RU payloads in the data field 324 .

[0062] Figure 3B Another example PPDU 350 that can be used for wireless communication between an AP and one or more STAs is shown. The PDU 350 can be used for SU, OFDMA, or MU-MIMO transmissions. The PDU 350 can be formatted as an extremely high throughput (EHT) WLAN PPDU according to the IEEE 802.11be amendment to the IEEE 802.11 wireless communication protocol standard, or can be formatted as a PPDU that complies with any future (post-EHT) version of a new wireless communication protocol (complying with future IEEE 802.11 wireless communication protocol standards or other wireless communication standards). The PDU 350 includes a PHY preamble that includes a legacy portion 352 and a non-legacy portion 354. The PDU 350 may also include a PHY payload 356 after the preamble (e.g., in the form of a PSDU including a data field 376).

[0063] The legacy portion 352 of the preamble includes an L-STF 358, an L-LTF 360, and an L-SIG 362. The non-legacy portion 354 of the preamble includes an RL-SIG 364 and a plurality of wireless communication protocol version-related signal fields following the RL-SIG 364. For example, the non-legacy portion 354 may include a universal signal field 366 (referred to herein as "U-SIG 366") and an EHT signal field 368 (referred to herein as "EHT-SIG 368"). One or both of the U-SIG 366 and the EHT-SIG 368 may be configured to be used for other wireless communication protocol versions above the EHT and carry information related to the version. The non-legacy portion 354 also includes an additional short training field 372 (referred to herein as "EHT-STF 372", but which may also be constructed and carry version-related information for wireless communication protocol versions other than EHT) and one or more additional long training fields 374 (referred to herein as "EHT-LTF 374", but they may be constructed and carry version-related information for wireless communication protocol versions other than EHT). As with the L-STF 358, L-LTF 360, and L-SIG 362, in instances involving the use of bonded channels, the information in the U-SIG 366 and the EHT-SIG 368 may be replicated and sent in each component 20 MHz channel. In some implementations, the EHT-SIG 368 may additionally or alternatively carry information in one or more non-primary 20 MHz channels that is different from the information carried in the primary 20 MHz channel.

[0064] The EHT-SIG 368 may include one or more jointly coded symbols and may be encoded in a different block from the block in which the U-SIG 366 is encoded. The EHT-SIG 368 may be used by the AP to identify multiple STAs 104 and notify the multiple STAs that the AP has scheduled UL or DL ​​resources for them. The EHT-SIG 368 may be decoded by each compatible STA 104 served by the AP 102. The EHT-SIG 368 may generally be used by the receiving device to interpret the bits in the data field 376. For example, the EHT-SIG 368 may include RU allocation information, spatial stream configuration information, and per-user signaling information (such as MCS) and other examples. The EHT-SIG 368 may also include a cyclic redundancy check (CRC) (e.g., four bits) and a tail (e.g., 6 bits) that may be used for a binary convolutional code (BCC). In some implementations, the EHT-SIG 368 may include one or more code blocks each including a CRC and a tail. In some aspects, each code block may be encoded separately.

[0065] The EHT-SIG 368 may carry STA-specific scheduling information, such as, for example, user-specific MCS values ​​and user-specific RU allocation information. The EHT-SIG 368 may generally be used by a receiving device to interpret bits in the data field 376. In the context of DL MU-OFDMA, such information enables the corresponding STA 104 to identify and decode the corresponding RU in the associated data field 376. Each EHT-SIG 368 may include a common field and at least one user-specific field. The common field may indicate the RU distribution to multiple STAs 104, indicate the RU assignment in the frequency domain, indicate which RUs are allocated for MU-MIMO transmission and which RUs correspond to MU-OFDMA transmission and the number of users in the allocation and other examples. The common field may be encoded with a common bit, a CRC bit, and a tail bit. The user-specific field is assigned to a specific STA 104 and may be used to schedule a specific RU and indicate the scheduling to other WLAN devices. Each user-specific field may include multiple user block fields. Each user block field may include, for example, two user fields containing information for two corresponding STAs to decode their corresponding RU payloads.

[0066] The presence of the RL-SIG 364 and the U-SIG 366 may indicate to the EHT or later version compatible STA 104 that the PPDU 350 is an EHT PPDU or a PPDU of any later (post-EHT) version that complies with a new wireless communication protocol (complying with future IEEE 802.11 wireless communication protocol standards). For example, the U-SIG 366 may be used by a receiving device to interpret bits in one or more of the EHT-SIG 368 or the data field 376.

[0067] Figure 4An example PPDU 400 is shown that can be used for communication between an AP 102 and a number of STAs 104. As described above, each PPDU 400 includes a PHY preamble 402 and a PSDU 404. Each PSDU 404 may carry one or more MAC protocol data units (MPDUs), such as, for example, an aggregate MPDU (A-MPDU) 406 including multiple MPDU subframes 408. Each MPDU subframe 408 may include a MAC delimiter 412 and a MAC header 414 before an accompanying frame body 416 (which includes the data portion or "payload" of the MPDU subframe 408). The frame body 416 may carry one or more MAC service data units (MSDUs), such as, for example, an aggregate MSDU (A-MSDU) 422 including multiple MSDU subframes 424. Each MSDU subframe 424 contains a corresponding MSDU 426, which includes a subframe header 428, a frame body 430, and one or more padding bits 432.

[0068] Referring back to the A-MPDU subframe 406, the MAC header 414 may include: several fields containing information defining or indicating characteristics or attributes of the data encapsulated within the frame body 416. The MAC header 414 also includes several fields indicating addresses for the data encapsulated within the frame body 416. For example, the MAC header 414 may include a combination of a source address, a transmitter address, a receiver address, or a destination address. The MAC header 414 may include: a frame control field containing control information. The frame control field specifies the frame type, for example, a data frame, a control frame, or a management frame. The MAC header 414 may also include a duration field indicating a duration extending from the end of the PPDU to the end of an acknowledgment (ACK) of the last PPDU to be sent by the wireless communication device (e.g., a block ACK (BA) in the case of an A-MPDU). The use duration field is used to reserve the wireless medium for the indicated duration, thereby establishing a NAV. Each A-MPDU subframe 408 may also include a frame check sequence (FCS) field 418 for error detection. For example, the FCS field 418 may include a cyclic redundancy check (CRC) and may be followed by one or more padding bits 420 .

[0069] As described above, the AP 102 and the STA 104 may support multi-user (MU) communications. That is, concurrent transmissions from one device to each of multiple devices (e.g., multiple simultaneous downlink (DL) communications from the AP 102 to the corresponding STAs 104), or concurrent transmissions from multiple devices to a single device (e.g., multiple simultaneous uplink (UL) transmissions from the corresponding STAs 104 to the AP 102). To support MU transmissions, the AP 102 and the STA 104 may utilize multi-user multiple-input multiple-output (MU-MIMO) and multi-user orthogonal frequency division multiple access (MU-OFDMA) techniques.

[0070] In the MU-OFDMA scheme, the available spectrum of a wireless channel may be divided into multiple resource units (RUs), each of which includes several different frequency subcarriers ("tones"). Different RUs may be allocated or assigned to different STAs 104 by AP 102 at a specific time. The size and distribution of RUs may be referred to as RU allocation. In some implementations, RUs may be allocated in 2MHz intervals, and in this way, the minimum RU may include 26 tones including 24 data tones and 2 pilot tones. Therefore, in a 20MHz channel, up to 9 RUs (such as 2MHz, 26-tone RUs) may be allocated (because some tones are reserved for other purposes). Similarly, in a 160MHz channel, up to 74 RUs may be allocated. Larger 52-tone, 106-tone, 242-tone, 484-tone, and 996-tone RUs may also be allocated. Adjacent RUs may be separated by nulled subcarriers, such as a DC subcarrier, for example, to reduce interference between adjacent RUs, reduce receiver DC offset, and avoid transmit center frequency leakage.

[0071] For UL MU transmissions, the AP 102 may send a trigger frame to initiate and synchronize UL MU-OFDMA or UL MU-MIMO transmissions from multiple STAs 104 to the AP 102. Such a trigger frame may thereby enable multiple STAs 104 to transmit UL traffic concurrently in time to the AP 102. The trigger frame may address one or more STAs 104 by a corresponding association identifier (AID), and may assign one or more RUs to each AID (and thus each STA 104), which may be used to transmit UL traffic to the AP 102. The AP may also specify one or more random access (RA) RUs that unscheduled STAs 104 may contend for.

[0072] Figure 5 1 shows a block diagram of an example wireless communication device 500. In some implementations, the wireless communication device 500 may be a wireless communication device for a STA (such as the one described above). Figure 1In some implementations, the wireless communication device 500 may be an example of a device in an AP (such as one of the STAs 104 described above). Figure 1 The wireless communication device 500 is an example of a device in the AP 102 described herein. The wireless communication device 500 is capable of sending (or outputting for sending) and receiving wireless communications (e.g., in the form of wireless packets). For example, the wireless communication device 500 may be configured to send 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) that comply with the IEEE 802.11 standard (such as the standard defined by the IEEE 802.11-2016 specification or its amendments, including but not limited to 802.11ah, 802.11ad, 802.11ay, 802.11ax, 802.11az, 802.11ba, and 802.11be).

[0073] The wireless communication device 500 may be or may include a chip, system on chip (SoC), chipset, package, or device including one or more modems 502 (e.g., Wi-Fi (IEEE 802.11 compliant) modems). In some implementations, one or more modems 502 (collectively, “modems 502”) additionally include a WWAN modem (e.g., a 3GPP 4G LTE or 5G compatible modem). In some implementations, the wireless communication device 500 also includes one or more radio components 504 (collectively, “radio components 504”). In some implementations, the wireless communication device 500 also includes one or more processors, processing blocks, or processing elements (collectively, “processor 506”) and one or more memory blocks or elements (collectively, “memory 508”).

[0074] The modem 502 may include an intelligent hardware block or device, such as an application specific integrated circuit (ASIC) or the like. The modem 502 is generally configured to implement the PHY layer. For example, the modem 502 is configured to modulate packets and output the modulated packets to the radio component 504 for transmission over the wireless medium. Similarly, the modem 502 is configured to obtain the modulated packets received by the radio component 504 and demodulate the packets to provide demodulated packets. In addition to the modulator and demodulator, the modem 502 may also include a digital signal processing (DSP) circuit system, an automatic gain control (AGC), a decoder, a decoder, a multiplexer, and a demultiplexer. For example, when in a transmit mode, data obtained from the processor 506 is provided to a decoder, which encodes the data to provide coded bits. The coded bits are mapped to points in the modulation constellation (using the selected MCS) to provide modulated symbols. The modulated symbols can be mapped to a number NSS The number of spatial streams or N is STS The modulated symbols in the corresponding spatial stream or space-time stream may be multiplexed, transformed via an inverse fast Fourier transform (IFFT) block, and then provided to the DSP circuit system for Tx windowing and filtering. The digital signal may be provided to a digital-to-analog converter (DAC). The resulting analog signal may be provided to an up-converter and ultimately to the radio component 504. In a specific implementation involving beamforming, the modulated symbols in the corresponding spatial stream are pre-decoded via a steering matrix before being provided to the IFFT block.

[0075] When in receive mode, a digital signal received from the radio component 504 is provided to a DSP circuit system, which is configured to acquire the received signal, for example, by detecting the presence of the signal and estimating the initial timing and frequency offset. The DSP circuit system is further configured to digitally condition the digital signal, for example, using channel (narrowband) filtering, analog impairment conditioning (such as correcting I / Q imbalance), and applying digital gain to ultimately obtain a narrowband signal. The output of the DSP circuit system may be fed to an AGC, which is configured to use information extracted from the digital signal (e.g., in one or more received training fields) to determine an appropriate gain. The output of the DSP circuit system is also coupled to a demodulator, which is configured to extract the modulated symbols from the signal and, for example, calculate a log-likelihood ratio (LLR) for each bit position of each subcarrier in each spatial stream. The demodulator is coupled to a decoder, which may be configured to process the LLRs to provide decoded bits. The decoded bits from all spatial streams are fed to a demultiplexer for demultiplexing. The demultiplexed bits may be descrambled and provided to the MAC layer (processor 506) for processing, evaluation, or interpretation.

[0076] The radio component 504 generally includes at least one radio frequency (RF) transmitter (or "transmitter chain") and at least one RF receiver (or "receiver chain"), which can be combined into one or more transceivers. For example, the RF transmitter and receiver may include various DSP circuit systems, including at least one power amplifier (PA) and at least one low noise amplifier (LNA), respectively. The RF transmitter and receiver may be further coupled to one or more antennas. For example, in some specific implementations, the wireless communication device 500 may include or be coupled to 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 502 are provided to the radio component 504, which transmits the symbols via the coupled antenna. Similarly, the symbols received via the antenna are obtained by the radio component 504, which provides the symbols to the modem 502.

[0077] The processor 506 may include an intelligent hardware block or device designed to perform the functions described herein, such as 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)), a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof. The processor 506 processes information received through the radio component 504 and the modem 502, and processes information to be output by the modem 502 and the radio component 504 for transmission through a wireless medium. For example, the processor 506 may implement a control plane and a MAC layer, which are 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, and other operations or techniques. In some specific implementations, the processor 506 may generally control the modem 502 so that the modem performs the above-mentioned various operations.

[0078] The memory 508 may include a tangible storage medium, such as a random access memory (RAM) or a read-only memory (ROM) or a combination thereof. The memory 508 may also store non-transitory processor or computer executable software (SW) code containing instructions that, when executed by the processor 506, cause the processor to perform various operations described herein for wireless communication, including generation, transmission, reception, and interpretation of MPDUs, frames, or packets. For example, the various functions of the various components disclosed herein or the various blocks or steps of the methods, operations, processes, or algorithms disclosed herein may be implemented as one or more modules of one or more computer programs.

[0079] Fig. 6A 602 is a block diagram of an example AP 602. For example, AP 602 may be a reference Figure 1 The AP 102 is described in detail with reference to an example implementation. The AP 602 includes a wireless communication device (WCD) 610. For example, the wireless communication device 610 may be a wireless communication device (WCD) 610. Figure 5The example implementation of the wireless communication device 500 described. The AP 602 also includes a plurality of antennas 620 coupled to the wireless communication device 610 to send and receive wireless communications. In some implementations, the AP 602 additionally includes an application processor 630 coupled to the wireless communication device 610 and a memory 640 coupled to the application processor 630. The AP 602 also includes at least one external network interface 650 that enables the AP 602 to communicate with a core network or a backhaul network to gain access to an external network including the Internet. For example, the external network interface 650 may include one or both of a wired (e.g., Ethernet) network interface and a wireless network interface (such as a WWAN interface). Components of the above components may communicate directly or indirectly with other components of the components via at least one bus. The AP 602 also includes a housing that surrounds the wireless communication device 610, the application processor 630, the memory 640, and at least portions of the antennas 620 and the external network interface 650.

[0080] Figure 6B 604. For example, STA 604 may be a reference Figure 1 The example implementation of STA 104 is described. STA 604 includes a wireless communication device 615. For example, the wireless communication device 615 may be a reference Figure 5 An example implementation of the wireless communication device 500 described. The STA 604 also includes one or more antennas 625 coupled to the wireless communication device 615 to send and receive wireless communications. The STA 604 additionally includes an application processor 635 coupled to the wireless communication device 615 and a memory 645 coupled to the application processor 635. In some implementations, the STA 604 also includes a user interface (UI) 655 (such as a touch screen or keyboard) and a display 665, which can be integrated with the UI 655 to form a touch screen display. In some implementations, the STA 604 may also include one or more sensors 675, such as one or more inertial sensors, accelerometers, temperature sensors, pressure sensors, or altitude sensors. Components of the above components can communicate directly or indirectly with other components of the components via at least one bus. The STA 604 also includes a housing that surrounds the wireless communication device 615, the application processor 635, the memory 645, and at least portions of the antenna 625, the UI 655, and the display 665.

[0081] Figure 7 is a block diagram of another example wireless network 700. In some aspects, the wireless network 700 may be Figure 1100. The wireless network 700 is shown as including a first AP 710A, a second AP 710B, a third AP 710C, and a STA 720. The APs 710A, 710B, and 710C may be any suitable access terminal, base station, or Wi-Fi access point, such as Figure 1 AP 102 Figure 5 The wireless communication device 500 or Fig. 6A AP 602. STA 720 may be any suitable wireless communication device, such as Figure 1 STA 104 Figure 5 The wireless communication device 500 or Figure 6B One of the STAs 604. Figure 7 In the example of FIG. 7 , STA 720 is associated with the first AP 710 and is not associated with the second AP 710B and the third AP 710C. Figure 7 Only three APs 710A-710C are shown in the example, but in some other instances, the example wireless communication 700 may include other numbers of APs. In other specific implementations, one or both of the second AP 710B or the third AP 710C may be replaced by a corresponding passive listening device (such as, for example, a passive STA).

[0082] In some implementations, the APs 710A, 710B, and 710C may be part of an extended basic service set (ESS) or an enterprise network that includes a backhaul connection 730 over which the APs 710A, 710B, and 710C may exchange information such as time delay, signal propagation time, TOD timestamp, TOA timestamp, time difference of arrival (TDOA) information, or TSF values, among other examples. In some instances, the APs 710A, 710B, and 710C may be connected to a network entity 740 via the backhaul connection 730. The network entity 740 may be a network controller, a network administrator, or other suitable entity that may control various operations, configurations, and parameters associated with the wireless network 700. For example, in some instances, the network entity 740 may store positioning information, timing relationships, and other information of the APs 710A-710C that may be used to obtain the location of the STA based on a pair of frames exchanged with the STA 720.

[0083] In some specific implementations, the first AP 710 may send a first frame to the STA 720 via a wireless channel, and the first AP 710 may capture a TOD timestamp of the first frame. In some instances, the TOD timestamp may correspond to the end of the transmission of the first frame by the first AP 710A. The STA 720 receives the first frame and responds by sending a second frame to the first AP 710A using the wireless channel. The time delay between the end of the reception of the first frame at the STA 720 and the start of the transmission of the second frame by the STA 720 may be a SIFS duration associated with the STA 720. The first AP 710A receives the second frame from the STA 720 and captures a TOA timestamp of the second frame. In some aspects, the TOA timestamp of the second frame may correspond to the start of the reception of the second frame by the first AP 710A.

[0084] In some instances, the STA 720, the second AP 710B, and the third AP 710C may be separated from the first AP 710A by different distances, and thus the first frame may be received by the STA 720, the second AP 710B, and the third AP 710C at different times. Similarly, the first AP 710A, the second AP 710B, and the third AP 710C may be separated from the STA 720 by different distances, and thus the second frame may be received by the first AP 710A, the second AP 710B, and the third AP 710C at different times. For example, in Figure 7 In the example of , the second AP 710B is located closest to the first AP 710A, followed by the third AP 710C, and then the STA 720. Therefore, the first frame arrives at the second AP 710B, then the third AP 710C (after a certain period of time), and then the STA 720 (after another period of time). Similarly, in Figure 7 In the example of FIG. 7 , the third AP 710C is located closest to the STA 720, followed by the second AP 710, and then the first AP 710A. Therefore, the second frame arrives at the third AP 710C, then the second AP 710B (after a certain period of time), and then the first AP 710A (after another period of time).

[0085] Figure 8 A sequence diagram of an example wireless communication 800 supporting a single-sided ranging operation is shown. The wireless communication 800 may be used with reference to Figure 7 The depicted STA 720 is associated with APs 710A, 710B, and 710C. As discussed, the STA 720 and the first AP 710A are associated with each other, and the STA 720 is not associated with the second AP 720B and the third AP 710C. Figure 8In the example of FIG. 7 , the third AP 710C is closest to the first AP 710A, followed by the second AP 710B, and then the STA 720. Thus, a frame transmitted by the first AP 710A first reaches the third AP 710C, then the second AP 710B, and then the STA 720. In addition, the second AP 710B is closest to the STA 720, followed by the third AP 710C, and then the first AP 710A. Thus, a frame transmitted by the STA 720 first reaches the second AP 710B, then the third AP 710C, and then the first AP 710A.

[0086] In some examples, at 802, the first AP 710A may assign a sequence number to a first frame to be sent by the first AP 710A to the STA 720. The assigned sequence number may be a unique or selected sequence number indicating that the first frame is associated with a ranging operation. In some other examples, the first AP 710A may embed a signal within the first frame indicating that the first frame is associated with a ranging operation. The signal may be embedded within any suitable portion of the first frame, including, but not limited to, reserved or unused bits of a preamble of the first frame, reserved or unused bits of a MAC header of the first frame, or reserved or unused bits of an element, sub-element, field, or sub-field following a MAC header of the first frame.

[0087] At 804, the first AP 710A may send an indication of the assigned sequence number or embedded signal to the second AP 710B and the third AP 710C (or other nearby passive listening devices). In some instances, the indication may be sent to the second AP 710B and the third AP 710C in an appropriate management frame, control frame, or action frame. In some other instances, the indication may be sent by reference to Figure 7 The backhaul connection 730 is described as being transmitted to the second AP 710B and the third AP 710C. In some other examples, the indication may be provided by reference to Figure 7 The depicted network entity 740 communicates to the second AP 710B and the third AP 710C.

[0088] In some aspects, the presence of the assigned sequence number or embedded signal in the frame sent by the first AP 710A can be an implicit instruction for the second AP 710B and the third AP 710C (and other nearby passive listening devices) to capture the TOA timestamp of the first frame, capture the TOA timestamp of the second frame sent in response to the first frame, and report the captured TOA timestamp to one or both of the first AP 710A or the network entity 740. In some other aspects, at 806, the first AP 710A can send explicit instructions for each of the second AP 710B and the third AP 710C to capture the TOA timestamp of the first frame, capture the TOA timestamp of the second frame, and report the captured TOA timestamp to one or both of the first AP 710A or the network entity 740.

[0089] The second AP 710B and the third AP 710C receive an indication of the assigned sequence number or embedded signal at 808 and 810, respectively, and listen for frames carrying the assigned sequence number or embedded signal at 812 based on implicit instructions associated with the indication or explicit instructions transmitted by the first AP 710A.

[0090] In some examples, at 814, the first AP 710A begins operation 800 by sending a first frame to the STA 720 using the wireless medium, and captures the TOD timestamp of the first frame as the TOD F1,A In some respects, TOD F1,A The timestamp may correspond to the end of transmission of the first frame (such as the last symbol of the first frame transmitted over the wireless medium). The first frame may indicate a sequence number (e.g., assigned at step 802) and may be any suitable frame, packet, or message that elicits a response from the STA 720. In some instances, the first frame may be a QoS null frame or an RTS frame. In other instances, the first frame may be a SU PPDU or a MU PPDU. In some other instances, the first frame may be a MU-RTS trigger frame or an NDP, among other examples.

[0091] STA 720 receives the first frame at 816 and confirms receipt of the first frame by sending a second frame to the first AP 710A using the wireless medium at 818. The second frame can be any suitable frame, packet, or message in response to the first frame. For example, the second frame can be an ACK frame in response to a QoS null frame sent by the first AP 710A, can be a CTS frame in response to an RTS frame, a MU-RTS trigger frame, or an NDP sent by the first AP 710A, or can be an ACK or BA frame in response to a SU PPDU or MU PPDU sent by the first AP 710A. As discussed, the time delay between the end of reception of the first frame by STA 720 and the start of transmission of the second frame by STA 720 can be a SIFS duration associated with STA 720.

[0092] The first AP 710A receives the second frame from the STA 720 at 820 and captures the TOA timestamp at the beginning of the reception of the second frame by the first AP 710A as the TOA F2,A At 822, the first AP 710A may obtain a time interval T indicating a time period T between the transmission of a first frame from the first AP 710A and the reception of a second frame by the first AP 710A. A Information. Time period T A It can be expressed as T A =TOD F1,A –TOA F2,A +S, where S is the SIFS duration associated with the STA 720. In some aspects, the first AP 710A may determine, calculate, or otherwise obtain the time period T A In other aspects, the first AP 710A may be from Figure 7 The network entity 740 obtains the time period T A .

[0093] The second AP 710B and the third AP 710C also receive the first frame transmitted by the first AP 710A and the second frame transmitted by the STA 720. Specifically, the second AP 710B receives the first frame from the first AP 710A at 824, and after a time delay, receives the second frame from the STA 720 at 826. The second AP 710B captures the TOA timestamp of the first frame as the TOA timestamp. F1,B , and capture the TOA timestamp of the second frame as TOA F2,B The time delay (T) between the end of reception of the first frame and the start of reception of the second frame at the second AP 710B B ) can be expressed as T B =TOA F2,B –TOA F1,BSimilarly, the third AP 710C receives the first frame from the first AP 710A at 828 and, after a time delay, receives the second frame from the STA 720 at 830. The third AP 710C captures the TOA timestamp of the first frame as the TOA F1,C , and capture the TOA timestamp of the second frame as TOA F2,C The time delay (T ) between the end of reception of the first frame and the start of reception of the second frame at the third AP 710C is C ) can be expressed as T C =TOA F2,C –TOA F1,C .

[0094] In some examples, at 832, the second AP 710B and the third AP 710C may report the corresponding time delays T to one or both of the first AP 710A or the network entity 740. B and T C In some other examples, the first AP 710A, the second AP 710B, and the third AP 710C may report to the network entity 740 the timing information associated with the corresponding time delay T A , T B and T C In some examples, the second AP 710B may transmit the time delay T to the first AP 710A in a corresponding third frame sent over the wireless medium. B The third AP 710C may transmit an indication of the time delay T to the first AP 710A in a corresponding third frame sent through the wireless medium. C In other examples, the second AP 710B may transmit the captured timestamp (TOA) to the first AP 710A in the corresponding third frame. F1,B and TOA F2,B ), and the third AP 710C may transmit the captured timestamp (TOA) to the first AP 710A in the corresponding third frame. F1,C and TOA F2,C ). The third frame may be a management frame, a control frame, or an action frame, among other examples. In some other examples, the second AP 710B may transmit the T to the first AP 710A or the network entity 740 via the backhaul connection 730. B An indication or a timestamp of the captured TOA F1,B and TOA F2,B , and the third AP 710C may transmit the T to the first AP 710A or the network entity 740 through the backhaul connection 730. C An indication or a timestamp of the captured TOA F1,C and TOA F2,C.

[0095] At 834, the first AP 710A may receive a third frame indicating respective time delays T associated with the second AP 710B and the third AP 710C. B and T C At 836, the first AP 710A may obtain a signal propagation time or distance between the first AP 710A and each of the second AP 710B and the third AP 710C from an associated memory or from the network entity 740. As discussed, the network entity 740 may store the locations of the APs 710A–710C as coordinates, and may obtain the distance between the first AP 710A and each of the second AP 710B and the third AP 710C based on the respective coordinates of the APs 710A–710C. In some instances, the coordinates of the APs 710A–710C may be relative to a reference location or coordinates, such as the location or coordinates of the first AP 710A. In other instances, the coordinates of the APs 710A–710C may be absolute coordinates, such as GPS or other satellite positioning system (SPS) coordinates.

[0096] In some aspects, the network entity 740 or the first AP 710A may obtain the signal propagation time based on the corresponding distance. For example, the signal propagation time T from the first AP to the second AP 710B is AB The distance between APs 710A and 710B can be obtained by dividing the distance between APs 710A and 710B by the speed of light c, and the signal propagation time T from the first AP to the third AP 710C is AC may be obtained by dividing the distance between APs 710A and 710C by c. As discussed, in some implementations, such as when APs 710A-710C are part of the same ESS or multiple BSSID sets, network entity 740 may be provided with the locations (such as GPS coordinates) of APs 710A-710C. In some aspects, network entity 740 may determine, calculate, or otherwise obtain the respective distances T of APs 710A-710C based on the respective locations or coordinates of APs 710A-710C. A , T B and T C .

[0097] In some examples, the first AP 710A can be based at least in part on the time period T A , the reported time delay T B and T C and the signal propagation time T AB and T AC720. In other examples, the first AP 710A may obtain (e.g., receive) the location of the STA 720 from the network entity 740. For example, the network entity 740 may estimate the location of the STA 720 and may transmit coordinates associated with the estimated location to the first AP 710A via the backhaul connection 730.

[0098] In some implementations, at 838, the first AP 710A may enable or disable one or more services for the STA 720 based on the obtained location of the STA 720. Specifically, in some instances, the first AP 710A may enable services for the STA 720 when the STA 720 is located within a specified area or structure, and may disable these services when the STA is no longer located within the specified area or structure. For example, the first AP 710A may be associated with a hotel, and may allow the STA 720 to access the hotel's wireless network when the STA 720 is located within a specified area or portion of the hotel (such as a lobby, a guest room, and a swimming pool, among other examples). When the STA 720 is no longer located within the specified area or portion, or when the STA is located within a restricted area or portion of the hotel (such as a spa, an employee area, or a storage area, among other examples), the first AP 710A may disable these services. In some aspects, the first AP 710A may transmit an indication of the enabled services or disabled services to the STA 720 in a fourth frame sent over the wireless medium.

[0099] In some examples, at 840, the first AP 710A may determine, calculate, or otherwise obtain a SIFS duration associated with the STA 720. In other examples, the first AP 710A may obtain the SIFS duration associated with the STA 720 from the network entity 740. In various aspects, at 842, the first AP 710A may transmit an indication of the SIFS duration to the STA 720 in a fifth frame sent over the wireless medium.

[0100] Fig. 9 A timing diagram of an example wireless communication 900 supporting a single-sided ranging operation is shown. The wireless communication 900 may be used with reference to Figure 7 The depicted STA 720 is associated with APs 710A, 710B, and 710C. As discussed, the STA 720 and the first AP 710A are associated with each other, and the STA 720 is not associated with the second AP 710B and the third AP 710C. Fig. 9In the example of FIG. 7 , the third AP 710C is closest to the first AP 710A, followed by the second AP 710B, and then the STA 720. Thus, a frame transmitted by the first AP 710A first reaches the third AP 710C, then the second AP 710B, and then the STA 720. In addition, the second AP 710B is closest to the STA 720, followed by the third AP 710C, and then the first AP 710A. Thus, a frame transmitted by the STA 720 first reaches the second AP 710B, then the third AP 710C, and then the first AP 710A.

[0101] At time t 0 At time t , the first AP 710A begins sending a first frame to the STA 720 over the wireless medium. As discussed, the first frame may be any suitable frame that elicits a response from the STA 720. 1 At , the last symbol of the first frame is sent through the wireless medium, and the first AP 710A captures the TOD timestamp of the first frame as TOD F1,A The end of the first frame is at time t 2 The third AP 710C captures the TOA timestamp of the second frame as the TOA F1,C Time t 1 With t 2 The time period between corresponds to the signal propagation time T between the first AP 710A and the third AP 710C. AC , and indicates the distance D between the first AP 710A and the third AP 710C AC .

[0102] The end of the first frame is at time t 3 The second AP 710B captures the TOA timestamp of the second frame as the TOA F1,B Time t 1 With t 3 The time period between corresponds to the signal propagation time T between the first AP 710A and the second AP 710B. AB , and indicates the distance D between the first AP 710A and the second AP 710B AB .

[0103] The end of the first frame is at time t 4 Arrives at STA 720. Time t 1 With t 4 The time period between corresponds to the signal propagation time T from the first AP 710A to the STA 720. AS, and indicates the distance D between the first AP 710A and the STA 720 AS At time t 4 With t 5 After a SIFS period between STA 720 and STA 720, STA 720 sends a 5 The first AP 710A starts sending a second frame to the first AP 710A over the wireless medium starting at 0. As discussed, in some instances, the first frame may be a QoS null frame or an RTS frame, and the second frame may be an ACK frame in response to the QoS null frame or a CTS frame in response to the RTS frame. In some other instances, the first frame may be one of a SU-PPDU or a MU PPDU sent over the entire bandwidth of the wireless channel, and the second frame may be an ACK frame or a BA frame received over the entire bandwidth of the wireless channel.

[0104] The beginning or start of the second frame is at time t 6 The second AP 710B captures the TOA timestamp of the second frame as the TOA F2,B Time t 5 With t 6 The time period between corresponds to the signal propagation time T from STA 720 to the second AP 710B. BS , and indicates the distance D between STA 720 and the second AP 710B BS Time t 3 With t 6 The time period between the first frame and the second frame corresponds to the time delay T between the respective receptions of the first frame and the second frame at the second AP 710B. B .

[0105] The beginning or start of the second frame is at time t 7 The third AP 710C captures the TOA timestamp of the second frame as the TOA F2,C Time t 5 With t 7 The time period between corresponds to the signal propagation time T from the STA 720 to the third AP 710C. CS , and instructs STA 720 to use a distance D between the third AP 710C CS Time t 2 With t 7 The time period between the first frame and the second frame corresponds to the time delay T between the respective receptions of the first frame and the second frame at the third AP 710C. C Although for simplicity in Fig. 9710B and the third AP 710C may send a corresponding time delay T to the first AP 710A or the network entity 740 via a wireless network or a distribution system. B and T C instructions.

[0106] The beginning or start of the second frame is at time t 8 The first AP 710A captures the TOA timestamp of the second frame as the TOA F2,A Time t 5 With t 8 The time period between corresponds to the signal propagation time T from the STA 720 to the first AP 710A. AS , and indicates the distance D between STA 720 and the first AP 710A AS Time t 1 With t 8 The time period between corresponds to the time period T between the first frame being sent from the first AP 710A and the second frame being received at the first AP 710A. A .

[0107] like Fig. 9 As depicted, time period T A It can be measured as the timestamp TOD captured by the first AP 710A F1,A with TOA F2,A The time difference between A =T AS +S+T AS , where S is the SIFS duration associated with STA 720. Time delay T B It can be measured as the timestamped TOA captured by the second AP 710B F1,B with TOA F2,B The time difference between B =T AS +S+T BS –T AB . Time delay T C It can be measured as the timestamped TOA captured by the third AP 710C F1,C with TOA F2,C The time difference between C =T AS +S+T CS –T AC As discussed, T may be derived from the stored coordinates of APs 710A- 710C. AB and T AC The value of , leaving four variables T associated with the three formulasAS , T BS , T CS and S.

[0108] Recognizing that four formulas are required to obtain the values ​​of the four variables, aspects of the subject matter disclosed herein may be interpreted as the signal propagation time T AS , T BS and T CS The quadratic expression of is incorporated into the above time value T A , T B and T C Specifically, the signal propagation time T AS , T BS and T CS Each of the coordinates P A , P B , P C and P S Expressed as , these coordinates respectively indicate the corresponding 2-dimensional positions of the first AP 710A, the second AP 710B, the third AP 710C, and the STA 720 through the following quadratic relationship:

[0109]

[0110] and

[0111]

[0112] Where P(x) represents the x-axis coordinate of the corresponding device, and P(y) represents the y-axis coordinate of the corresponding device. A (x) may represent the x-axis coordinate of the first AP 710A, and P A (y) may represent the y-axis coordinate of the first AP 710A; B (x) may represent the x-axis coordinate of the second AP 710B, and P B (y) may represent the y-axis coordinate of the second AP 710B; C (x) may represent the x-axis coordinate of the third AP 710C, and P C (y) may represent the y-axis coordinate of the third AP 710C; S (x) may represent the x-axis coordinate of STA 720, and P S (y) may represent the y-axis coordinate of STA 720. As discussed, in some implementations, such as when APs 710A-710C are part of the same ESS or multiple BSSID sets, network entity 740 may be provided with the corresponding 2-dimensional coordinates P of APs 710A-710C. A (x),P A (y); PB (x),P B (y); and P C (x),P C (y). In some aspects, the network entity 740 may determine, calculate, or otherwise obtain the signal propagation time T between the APs 710A- 710C based on their respective locations or coordinates. AB , T AC and T BC In some aspects, the network entity 740 provides each of the first AP 710A, the second AP 710B, and the third AP 710C with one or both of the coordinates or the signal propagation times of the APs 710A-710C.

[0113] Fig. 10A An illustration 1000 depicting an example 2-dimensional positioning of a wireless device is shown. The illustration 1000 shows reference to the corresponding signal propagation times between the first AP 710A, the second AP 710B, the third AP 710C, and the STA 720. Figures 7 to 9 The distances between the first AP 710A, the second AP 710B, the third AP 710C and the STA 720 are shown. As shown in the figure, the signal propagation time between the first AP 710A and the STA 720 is T AS , and the distance D between the first AP 710A and the STA 720 AS Yes D AS =T AS *c, where c is the speed of light. The signal propagation time between the second AP 710B and the STA 720 is T BS , and the distance D between the second AP 710B and the STA 720 BS Yes D BS =T BS *c. The signal propagation time between the third AP 710C and the STA 720 is T CS , and the distance D between the third AP 710C and the STA 720 CS Yes D CS =T CS *c.

[0114] In some examples, the time period T associated with the first AP 710A A The relationship between the difference between the position coordinates (P) of the first AP 710A and the STA 720 may be used as a fourth expression to obtain the distance between the first AP 710A and the STA 720. For example, in some aspects, the position coordinates of the first AP 710A and the STA 720 may be inserted into T as follows: A In the time delay expression:

[0115]

[0116] Similarly, the time period T associated with the second AP 710B B The relationship between the difference between the position coordinates (P) of the second AP 710B and the STA 720 may be used as a fourth expression to obtain the distance between the second AP 710B and the STA 720. For example, in some aspects, the position coordinates of the second AP 710B and the STA 720 may be inserted into T as follows B In the time delay expression:

[0117]

[0118] Similarly, the time period T associated with the third AP 710C C The relationship between the difference between the position coordinates (P) of the third AP 710C and the STA 720 may be used as a fourth expression to obtain the distance between the third AP 710C and the STA 720. For example, in some aspects, the position coordinates of the third AP 710C and the STA 720 may be inserted into T as follows: C In the time delay expression:

[0119]

[0120] By incorporating the quadratic expression relating the signal propagation time to the coordinates of the APs 710A-710C into the time delay expression, there are now four formulas that are used to solve for the four variables T AS , T BS , T CS and S, these four variables may be solved by the first AP 710A or the network entity 740.

[0121] In some implementations, one or both of the first AP 710A or the network entity 740 may use the corresponding relationship between the time delay and the coordinates of each of the APs 710A-710C and the coordinates of the APs 710A-710C to determine, calculate, or otherwise obtain the position coordinates of the STA 720 and thus obtain the positioning of the STA. In some aspects, the obtained position coordinates of the STA 720 may be relative to the position coordinates of the first AP 710A. In some other aspects, the obtained position coordinates of the STA 720 may be absolute coordinates, such as, for example, GPS coordinates.

[0122] Fig. 10B Illustration 1050 is shown depicting an example 3-dimensional positioning of a wireless device. Illustration 1050 indicates Fig. 10AThe first AP 710A, the second AP 710B, the third AP 710C and the STA 720 are indicated, and the corresponding distance between the fourth AP 710D and each of the first AP 710A, the second AP 710B, the third AP 710C and the STA 720 is also indicated. Fig. 10B In the example of FIG. 7 , the STA 720, the first AP 710A, the second AP 710B, and the third AP 710C are located in the same plane (e.g., xy position) as each other, and the fourth AP 710D is elevated (e.g., along a z-axis perpendicular to the xy plane). For example, in some instances, the STA 720, the first AP 710A, the second AP 710B, and the third AP 710C may be located on the second floor of a building, and the fourth AP 710D may be located on the third floor of the building. In some aspects, the fourth AP 710D may be used to obtain a reference image based at least in part on the reference image captured by the fourth AP 710D. Figure 8 The TOA timestamps of the first frame and the second frame are described to determine, calculate, or otherwise obtain the 3-dimensional position of the STA 720 (eg, the 3-dimensional coordinates of the STA 720 ).

[0123] As discussed, the distance D between the first AP 710A and the STA 720 is AS Yes D AS =T AS *c, where c is the speed of light. The signal propagation time between the second AP 710B and the STA 720 is T BS , and the distance D between the second AP 710B and the STA 720 BS Yes D BS =T BS *c. The signal propagation time between the third AP 710C and the STA 720 is T CS , and the distance D between the third AP 710C and the STA 720 CS Yes D CS =T CS *c. In addition, refer to Fig. 9 , time period T A It can be measured as the timestamp TOD captured by the first AP 710A F1,A with TOA F2,A The time difference between A =T AS +S+T AS , where S is the SIFS duration associated with STA 720. Time delay T B It can be measured as the timestamped TOA captured by the second AP 710B F1,B with TOA F2,BThe time difference between B =T AS +S+T BS –T AB . Time delay T C It can be measured as the timestamped TOA captured by the third AP 710C F1,C with TOA F2,C The time difference between C =T AS +S+T CS –T AC .

[0124] The signal propagation time between the fourth AP 710D and the STA 720 is T DS , and the distance D between the fourth AP 710D and the STA 720 DS Yes D CS =T CS *c. The signal propagation time between the fourth AP 710D and the first AP 710A is T AD , and the distance D between the fourth AP 710D and the first AP 710A AD Yes D AD =T AD *c. The signal propagation time between the fourth AP 710D and the second AP 710B is T BD , and the distance D between the fourth AP 710D and the second AP 710B BD Yes D BD =T BD *c. The signal propagation time between the fourth AP 710D and the third AP 710C is T CD , and the distance D between the fourth AP 710D and the third AP 710C CD Yes D CD =T CD *c.

[0125] In some implementations, the fourth AP 710D may capture Figure 8 The TOA timestamp of the first frame sent by the first AP 710 is used as the TOA F1,D , and can capture Figure 8 STA 720 sends the TOA timestamp of the second frame as the TOA F2,D . Time delay T D It can be measured as the timestamped TOA captured by the fourth AP 710D F1,D with TOA F2,D The time difference between D =T DS +S+TDS –T DC .

[0126] Recognizing that four formulas are required to obtain values ​​for the five variables, aspects of the subject matter disclosed herein may be used to convert the signal propagation time T AS , T BS , T CS and T DS The quadratic expression of is incorporated into the above time value T A , T B , T C and T D Specifically, the signal propagation time T AS , T BS , T CS and T DS Each of the coordinates P A , P B , P C , P D and P S Expressed as , these coordinates respectively indicate the corresponding 3-dimensional positions of the first AP 710A, the second AP 710B, the third AP 710C, the fourth AP 710D, and the STA 720 through the following quadratic relationship:

[0127]

[0128] and

[0129]

[0130] Where P(x) represents the x-axis coordinate of the corresponding device, P(y) represents the y-axis coordinate of the corresponding device, and P(z) represents the z-axis coordinate of the corresponding device. A (x) may represent the x-axis coordinate of the first AP 710A, A (y) may represent the y-axis coordinate of the first AP 710A, and P A (z) may represent the z-axis coordinate of the first AP 710A; B (x) may represent the x-axis coordinate of the second AP 710B, B (y) may represent the y-axis coordinate of the second AP 710B, and P B (z) may represent the z-axis coordinate of the second AP 710B; C (x) may represent the x-axis coordinate of the third AP 710C, C (y) may represent the y-axis coordinate of the third AP 710C, and P C (z) may represent the z-axis coordinate of the third AP 710C; D(x) may represent the x-axis coordinate of the fourth AP 710D, D (y) may represent the y-axis coordinate of the fourth AP 710D, and P D (z) may represent the z-axis coordinate of the fourth AP 710D; S (x) may represent the x-axis coordinate of STA 720, P S (y) may represent the y-axis coordinate of STA720, and P S (z) may represent the z-axis coordinate of STA 720 .

[0131] In some implementations, such as when the APs 710A-710D are part of the same ESS or multiple BSSID sets, the network entity 740 may be provided with the respective 3-dimensional coordinates P of the APs 710A-710D. A (x),P A (y),Pa(z) A (z). In some aspects, network entity 740 may determine, calculate, or otherwise obtain a signal propagation time T between 710A-710D based on their respective locations or coordinates. AB , T AC , T BC , T AD , T BD and T CD In some aspects, the network entity 740 provides each of the first AP 710A, the second AP 710B, the third AP 710C, and the fourth AP 710D with one or both of the coordinates or the signal propagation time of the APs 710A-710D.

[0132] In some examples, the location coordinates of the first AP 710A and the STA 720 may be inserted into T as follows: A In the time delay expression:

[0133]

[0134] The location coordinates of the second AP 710B and STA 720 may be inserted into T as follows B In the time delay expression:

[0135]

[0136] The location coordinates of the third AP 710C and STA 720 may be inserted into T as follows C In the time delay expression:

[0137]

[0138] The location coordinates of the fourth AP 710D and STA 720 may be inserted into T as follows D In the time delay expression:

[0139]

[0140] By incorporating the quadratic expression relating the signal propagation time to the coordinates of the APs 710A-710D into the time delay expression, there are now five formulas that are used to solve for the five variables T AS , T BS , T CS , T DS and S, these five variables may be solved by the first AP 710A or the network entity 740.

[0141] In some implementations, one or both of the first AP 710A or the network entity 740 may use the corresponding relationship between the time delay and the coordinates of each of the APs 710A-710D and the coordinates of the APs 710A-710D to determine, calculate, or otherwise obtain the position coordinates of the STA 720 and thus obtain the positioning of the STA. In some aspects, the obtained position coordinates of the STA 720 may be relative to the position coordinates of the first AP 710A. In some other aspects, the obtained position coordinates of the STA 720 may be absolute coordinates, such as, for example, GPS coordinates.

[0142] Fig.11 1 is a flow chart illustrating example operations 1100 for wireless communications supporting single-sided ranging operations. Operations 1100 may be performed by a wireless communication device (such as the one described above with reference to FIG. Figure 5 In various implementations, the operations 1100 may be performed by an AP (such as the wireless communication device 500 described in the accompanying drawings). Figure 1 and Figure 6B In some examples, operations 1100 may be performed by a first device operating in or within an AP 102 or 602 as described herein. Figures 7 to 9 The first AP 710A described is performed.

[0143] For example, at 1102, a first device sends a first frame to a wireless station (STA). At 1104, the first device receives a second frame from the STA, the second frame responding to the first frame. At 1106, the first device obtains information indicating a time period between the first device sending the first frame and the first device receiving the second frame. At 1108, the first device obtains information indicating time delays associated with a plurality of second devices, wherein each of the time delays is between respective receptions of the first frame and the second frame by respective second devices in the plurality of second devices. At 1110, the first device obtains a position of the STA based on the time period, the time delays associated with the plurality of second devices, and the signal propagation time between the first device and each of the plurality of second devices. At 1112, in response to the position of the STA, the first device selectively enables or disables one or more services for the STA.

[0144] In various implementations, the position of the STA may be obtained independently of a time period or time delay associated with the STA. In this way, the position of the STA may be obtained without estimating a SIFS duration associated with the STA, which may improve the accuracy with which the position of the STA may be estimated, determined, or otherwise obtained. In addition, by obtaining the position of the STA independently of a time period or time delay associated with the STA, implementations of the subject matter disclosed herein do not receive any measurements from the STA for positioning, which may reduce the amount of overhead or congestion associated with frame exchanges on a shared wireless medium, as discussed.

[0145] In some implementations, the first frame may be a quality of service (QoS) null frame or a ready to send (RTS) frame, and the second frame may be an acknowledgement (ACK) frame in response to the QoS null frame, or may be a clear to send (CTS) frame in response to the RTS frame. In some other implementations, the first frame may be one of a single user (SU) physical layer protocol data unit (PPDU) or a multi-user (MU) PPDU sent over the entire bandwidth of the wireless channel, and the second frame may be an acknowledgement (ACK) frame or a block ACK (BA) frame received over the entire bandwidth of the wireless channel.

[0146] In some implementations, the time period may be associated with the end of transmission of the first frame and the beginning of reception of the second frame at the first device. In some instances, each of the time delays may be associated with the end of reception of the first frame and the beginning of reception of the second frame by the corresponding second device. In some other implementations, the time period may be equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the first device. In some instances, the time delay associated with the corresponding second device may be equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the corresponding second device minus the signal propagation time from the first device to the second device.

[0147] Fig.12 A flow chart illustrating example operations 1200 for wireless communications supporting single-sided ranging operations is shown. Operations 1200 may be performed by a wireless communication device (such as the one described above with reference to FIG. Figure 5 In various implementations, the operations 1200 may be performed by an AP (such as the wireless communication device 500 described in the accompanying drawings). Figure 1 and Figure 6B 102 or 602) described herein) or a first device operating within an AP. In some aspects, operations 1200 may be performed by reference to Figures 7 to 9 The first AP 710A described is performed.

[0148] In some examples, operation 1200 may be performed in Fig.11 An example of selectively enabling or disabling one or more services at 1112 of . For example, at 1202, in response to the location of the STA being within an area or structure, the first device enables one or more services for the STA. At 1204, in response to the location of the STA being outside the area or structure, the first device disables one or more services for the STA. In some specific implementations, the first device may enable one or more services for the STA when the STA is within the area or structure, and may continue to enable the one or more services as long as the STA remains within the area or structure. For example, the first device may be associated with a hotel, and may allow the STA to access the hotel's wireless network when the STA is within a designated area or portion of the hotel (such as a lobby, a guest room, and a swimming pool, among other examples). In some instances, the first device may transmit an indication of the enabled services to the STA in a frame sent over the wireless medium. When the STA is no longer within the designated area or portion, or when the STA is within a restricted area or portion of the hotel (such as a spa, an employee area, or a storage area, among other examples), the first device may disable the services provided to the STA.

[0149] Fig.13 A flow chart illustrating example operations 1300 for wireless communications supporting single-sided ranging operations is shown. Operations 1300 may be performed by a wireless communication device (such as the one described above with reference to FIG. Figure 5 In various implementations, the operations 1300 may be performed by an AP (such as the wireless communication device 500 described in the accompanying drawings). Figure 1 and Figure 6B 102 or 602) described herein) or a first device operating within an AP. In some aspects, operations 1300 may be performed by reference to Figures 7 to 9 The first AP 710A described is performed.

[0150] In some examples, operation 1300 may be combined with Fig.11 The method may be performed by the operation 1100 of . For example, at 1302, the first device assigns a sequence number to the first frame. At 1304, the first device sends an indication of the sequence number to each of the plurality of second devices. At 1306, the first device sends an instruction to each of the plurality of second devices to report the time of arrival (TOA) timestamps of all first frames carrying the indicated sequence number and to report the TOA timestamps of all second frames sent over the wireless medium in response to the first frame. In other specific implementations, the presence of the assigned sequence number in the first frame may be an implicit instruction for the second device to capture the TOA timestamp of the first frame, capture the TOA timestamps of other frames sent in response to the first frame, and report the captured TOA timestamps to one or both of the first device or the network entity.

[0151] In some implementations, the assigned sequence number may be a unique or selected value indicating that the first frame is associated with a ranging operation. In some instances, the indication may be sent to each of the second devices in a suitable management frame, control frame, or action frame. In other instances, the indication may be transmitted to each of the second devices via a backhaul connection. In some other instances, the indication may be sent by reference to Figure 7 The described network entity is transmitted to each of the second devices.

[0152] Fig.14 A flow chart illustrating example operations 1400 for wireless communications supporting single-sided ranging operations is shown. Operations 1400 may be performed by a wireless communication device (such as the one described above with reference to FIG. Figure 5 In various implementations, the operations 1400 may be performed by an AP (such as the wireless communication device 500 described in the accompanying drawings). Figure 1 and Figure 6B102 or 602) described herein) or a first device operating within an AP. In some aspects, operations 1400 may be performed by reference to Figures 7 to 9 The first AP 710A described is performed.

[0153] In some examples, operation 1400 may be combined with Fig.11 The method may be performed by the operation 1100 of . For example, at 1402, the first device embeds a signal or value in a first frame. At 1404, the first device sends an indication of the signal or value to each of the plurality of second devices. At 1406, the first device sends an instruction to each of the plurality of second devices for reporting the time of arrival (TOA) timestamps of all first frames carrying the embedded signal or value and reporting the TOA timestamps of all second frames in response to the first frame carrying the embedded signal or value. In other specific implementations, the presence of the embedded signal or value in the first frame may be an implicit instruction for the second device to capture the TOA timestamp of the first frame, capture the TOA timestamps of other frames sent in response to the first frame, and report the captured TOA timestamps to one or both of the first device or the network entity.

[0154] In some implementations, the embedded signal or value may be indicated by one of a reserved or unused bit of a preamble of the first frame, a reserved or unused bit of a MAC header of the first frame, or a reserved or unused bit of an element, field, or subfield following the MAC header of the first frame. In some instances, the indication may be sent to each of the second devices in a suitable management frame, control frame, or action frame. In other instances, the indication may be transmitted to each of the second devices via a backhaul connection. In some other instances, the indication may be sent by a reference to Figure 7 The described network entity is transmitted to each of the second devices.

[0155] In other specific implementations, the AP 710A may not transmit an indication of the frames for which the second AP 710B and the third AP 710C are to capture their TOA timestamps. For example, in some instances, the second AP 710B and the third AP 710C may capture the TOA timestamps of frames received from a particular AP or STA during the time window. In other instances, the second AP 710B and the third AP 710C may capture the TOA timestamps of all frames received during the time window. In some other instances, the second AP 710B and the third AP 710C may capture the TOA timestamps of frames exchanged between a particular AP and a particular STA (e.g., during the time window).

[0156] Fig.15A flow chart illustrating example operations 1500 for wireless communications supporting single-sided ranging operations is shown. Operations 1500 may be performed by a wireless communication device (such as the one described above with reference to FIG. Figure 5 In various implementations, the operations 1500 may be performed by an AP (such as the wireless communication device 500 described in the accompanying drawings). Figure 1 and Figure 6B In some aspects, the operations 1500 may be performed by a first device operating in or within the AP 102 or 602 described herein. Figures 7 to 9 The first AP 710A described is performed.

[0157] In some examples, operation 1500 may be performed in Fig.11 In one example, the first device may receive information indicating a time delay associated with a plurality of second devices at 1108. For example, in some aspects, at 1502, the first device receives a third frame from each of the plurality of second devices, the third frame indicating a time delay associated with the respective second device. In other aspects, at 1504, the first device obtains coordinates of the STA relative to the coordinates of the first device from a network entity.

[0158] Fig.16 A flow chart illustrating example operations 1600 for wireless communications supporting single-sided ranging operations is shown. Operations 1600 may be performed by a wireless communication device (such as the one described above with reference to FIG. Figure 5 In various implementations, the operations 1600 may be performed by an AP (such as the wireless communication device 500 described in the accompanying drawings). Figure 1 and Figure 6B 102 or 602) described herein) or a first device operating within an AP. In some aspects, operations 1600 may be performed by reference to Figures 7 to 9 The first AP 710A described is performed.

[0159] In some examples, operation 1600 may be performed in Fig.11 An example of obtaining the position of the STA at 1110 of the present invention. For example, at 1602, the first device obtains a first relationship between a time period and a difference between the coordinates of the STA and the coordinates of the first device. At 1604, for each second device in a plurality of second devices, the first device obtains a second relationship between a corresponding time delay associated with the corresponding second device and a difference between the coordinates of the STA and the coordinates of the corresponding second device. At 1606, the first device obtains the coordinates of the plurality of second devices. At 1608, for each corresponding second device in the plurality of second devices, the first device obtains the coordinates of the STA based on trilateration of the first relationship and the second relationship.

[0160] In some implementations, the example operation 1600 may be continued. For example, at 1610, the first device obtains a SIFS duration associated with the STA based on the first relationship and the plurality of corresponding second relationships. At 1612, the first device sends an indication of the SIFS duration to the STA. As discussed, the time period may be equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the first device. The time delay associated with the corresponding second device may be equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the corresponding second device minus the signal propagation time from the first device to the second device.

[0161] Fig.17 1 shows a block diagram of an example wireless communication device 1700. In some implementations, the wireless communication device 1700 may be configured to perform the above-mentioned Fig.11 , Fig.12 , Fig.13 , Fig.14 , Fig.15 and Fig.16 One or more of the described operations 1100, 1200, 1300, 1400, 1500, or 1600. The wireless communication device 1700 may be Figure 1 AP 102 Figure 5 A wireless communication device 500, Fig. 6A AP 602 or reference Figures 7 to 9 An example implementation of any of the described first AP 710A. More specifically, the wireless communication device 1700 may be a chip, SoC, chipset, package, or device including at least one processor and at least one modem (eg, a Wi-Fi (IEEE 802.11) modem or a cellular modem).

[0162] The wireless communication device 1700 includes a receiving component 1710, a communication manager 1720, and a transmitting component 1730. The communication manager 1720 includes a ranging component 1722, a measuring component 1724, and a position determination component 1726. Portions of one or more of the components 1722, 1724, and 1726 may be implemented at least in part in hardware or firmware. In some implementations, one or more of the components 1722, 1724, and 1726 may be implemented at least in part as stored in a memory (such as a Figure 5 For example, portions of one or more of components 1724 or 1726 may be implemented as software that can be executed by a processor such as Figure 5The processor 506 of the processor 506 is executed to perform the non-transitory instructions (or "code") of the corresponding component. In some other specific implementations, the location determination component 1726 can reside in the network entity 740.

[0163] The transmitting component 1730 is configured to transmit a TX signal to one or more other wireless communication devices. For example, in some instances, the transmitting component 1730 may be configured to transmit a first frame to a STA in order to perform ranging on the STA. The transmitting component 1730 may also be configured to transmit an indication of a sequence number assigned to the first frame or a signal or value embedded in the first frame. In some instances, the transmitting component 1730 may be configured to transmit instructions for nearby passive listening devices to capture the TOA timestamp of the first frame, capture the TOA timestamps of other frames transmitted in response to the first frame, and transmit a reference to the TOA timestamp. Figure 7 One or both of the depicted wireless communication device 1700 or network entity reports the captured TOA timestamp.In other examples, the transmitting component 1730 can be configured to transmit an indication of the SIFS duration to the STA.

[0164] The receiving component 1710 is configured to receive RX signals from one or more other wireless communication devices. In some instances, the receiving component 1710 may be configured to receive a second frame sent by the STA, the second frame responding to the first frame. The receiving component 1710 may also be configured to obtain information indicating a time delay associated with each of the passive listening devices in the vicinity, wherein each of the time delays is between respective receptions of the first frame and the second frame by respective passive listening devices in the vicinity.

[0165] The communication manager 1720 is configured to manage wireless communications with other wireless communication devices. In some specific implementations, the ranging component 1722 may assign a sequence number to the first frame sent to the STA, or embed a signal or value therein. The assigned sequence number or the embedded signal may indicate that the first frame is associated with the ranging operation of the STA. The measurement component 1724 may be configured to obtain information indicating the time period between the wireless communication device 1700 sending the first frame and the wireless communication device 1700 receiving the second frame. In some instances, the measurement component 1724 may also be configured to obtain a time delay associated with a nearby passive listening device. In some aspects, the measurement component 1724 may also be configured to obtain a SIFS duration associated with the STA. The position determination component 1726 may be configured to obtain the position of the STA based on the time period, the time delay associated with the nearby passive listening device, and the signal propagation time between the first device and each of the nearby passive listening devices.

[0166] In some configurations, the wireless communication device 1700 may include components for all of the component limitations described herein. In some instances, the aforementioned components may be Figure 5 One or more of the modem 502, the radio component 504, the processor 506, or the memory 508. In some examples, the aforementioned components may be Fig. 6A One or more of the memory 640, the application processor 630, the WCD 610, or the antenna 620. In some other examples, the aforementioned components may be Fig.17 One or more of the aforementioned components 1722, 1724 and 1726 of the wireless communication device 1700.

[0167] In some examples, means for sending a first frame may include Figure 5 The modem 502 and the radio component 504, Fig. 6A WCD 610 and antenna 620 or Fig.17 In some examples, the component for receiving the second frame from the STA may include Figure 5 The modem 502 and the radio component 504, Fig. 6A WCD 610 and antenna 620 or Fig.17 In some examples, the component for obtaining information indicating a time period may include: Figure 5 A processor 506 and a memory 508, Fig. 6A Memory 640, application processor 630 and WCD 610 or Fig.17 The position determination component 1726. In some examples, the means for obtaining information indicating the time delay may include Figure 5 The modem 502 and the radio component 504, Fig. 6A WCD 610 and antenna 620 or Fig.17 In some examples, the component for obtaining the location of the STA may include Figure 5 A processor 506 and a memory 508, Fig. 6A Memory 640, application processor 630 and WCD 610 or Fig.17 The location of component 1726 is determined.

[0168] Example aspects

[0169] Aspect 1: A first device, the first device comprising: at least one processor; and at least one memory, the at least one memory being communicatively coupled to the at least one processor and storing processor-readable code, the processor-readable code being configured to: send a first frame to a wireless station (STA); receive a second frame from the STA, the second frame being in response to the first frame; obtain information indicating a time period between the first device sending the first frame and the first device receiving the second frame; obtain information indicating time delays associated with a plurality of second devices, wherein each of the time delays is between corresponding reception of the first frame and the second frame by a corresponding second device among the plurality of second devices; and obtain a position of the STA based on the time period, the time delays associated with the plurality of second devices, and a signal propagation time between the first device and each of the plurality of second devices.

[0170] Aspect 2: The first device according to Aspect 1, wherein the execution of the processor readable code is further configured to: in response to the position of the STA being within an area or a structure, enable one or more services for the STA; or in response to the position of the STA being outside the area or the structure, disable the one or more services for the STA.

[0171] Aspect 3: A first device according to any one or more of Aspects 1 to 2, wherein the first frame includes a quality of service (QoS) empty frame or a ready to send (RTS) frame, and the second frame includes an acknowledgment (ACK) frame in response to the QoS empty frame or a clear to send (CTS) frame in response to the RTS frame.

[0172] Aspect 4: A first device according to any one or more of Aspects 1 to 2, wherein the first frame includes one of a single-user (SU) physical layer protocol data unit (PPDU) or a multi-user (MU) PPDU sent over the entire bandwidth of a wireless channel, and the second frame includes an acknowledgment (ACK) frame or a block ACK (BA) frame received over the entire bandwidth of the wireless channel.

[0173] Aspect 5: A first device according to any one or more of Aspects 1 to 4, wherein the first device comprises a first access point (AP) associated with the STA, and the plurality of second devices comprises a plurality of corresponding passive listening devices not associated with the STA.

[0174] Aspect 6: The first device according to aspect 5, wherein executing the processor readable code to obtain the time delay is further configured to: receive a third frame from each second device of the plurality of second devices, the third frame indicating a corresponding time delay associated with the corresponding second device.

[0175] Aspect 7: The first device according to any one or more of Aspects 1 to 5, wherein one or both of the information indicating the time delays associated with the plurality of second devices or the information indicating the location of the STA is obtained from a network entity.

[0176] Aspect 8: The first device according to aspect 7, wherein executing the processor readable code to obtain the position of the STA is further configured to: obtain coordinates of the STA relative to coordinates of the first device from the network entity.

[0177] Aspect 9: A first device according to any one or more of Aspects 1 to 8, wherein executing the processor readable code is further configured to: assign a sequence number to the first frame; send an indication of the sequence number to each of the multiple second devices; and send instructions to each of the multiple second devices for reporting the time of arrival (TOA) timestamps of all first frames carrying the indicated sequence number and reporting the TOA timestamps of all second frames in response to the first frame.

[0178] Aspect 10: The first device according to any one or more of aspects 1 to 9, wherein the location of the STA is obtained independent of a time period or time delay associated with the STA.

[0179] Aspect 11: A first device according to any one or more of Aspects 1 to 10, wherein the time period is associated with the end of the sending of the first frame and the start of the receiving of the second frame; and each of the time delays is associated with the end of the receiving of the first frame and the start of the receiving of the second frame by the corresponding second device among the multiple second devices.

[0180] Aspect 12: A first device according to any one or more of Aspects 1 to 11, wherein the time period is equal to the sum of the signal propagation time from the first device to the STA, the short interframe space (SIFS) duration associated with the STA, and the signal propagation time from the STA to the first device; and the corresponding time delay associated with the corresponding second device is equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the corresponding second device minus the signal propagation time from the first device to the second device.

[0181] Aspect 13: A first device according to Aspect 12, wherein executing the processor readable code to obtain the position of the STA is further configured to: obtain a first relationship between the time period and the difference between the coordinates of the STA and the coordinates of the first device; for each second device among the multiple second devices, obtain a second relationship between the corresponding time delay associated with the corresponding second device and the difference between the coordinates of the STA and the coordinates of the corresponding second device; obtain the coordinates of the multiple second devices; and for each corresponding second device among the multiple second devices, obtain the coordinates of the STA based on trilateral measurement of the first relationship and the second relationship.

[0182] Aspect 14: A first device according to Aspect 13, wherein executing the processor readable code is further configured to: for each corresponding second device among the multiple second devices, obtain the SIFS duration associated with the STA based on the first relationship and the second relationship; and send an indication of the SIFS duration to the STA.

[0183] Aspect 15: A first device according to any one or more of Aspects 1 to 14, wherein executing the processor readable code is further configured to: embed a signal or value within the first frame; send an indication of the signal or the value to each of the multiple second devices; and send instructions to each of the multiple second devices for reporting arrival time (TOA) timestamps of all first frames carrying the embedded signal or value and reporting TOA timestamps of all second frames in response to the first frame carrying the embedded signal or value.

[0184] Aspect 16: A first device according to Aspect 15, wherein the embedded signal or value is indicated by one of a reserved or unused bit of a preamble code of the first frame, a reserved or unused bit of a medium access control (MAC) header of the first frame, or a reserved or unused bit of an element, field or subfield after the MAC header of the first frame.

[0185] Aspect 17: A method for wireless communication by a first device, the method comprising: sending a first frame to a wireless station (STA); receiving a second frame from the STA, the second frame being in response to the first frame; obtaining information indicating a time period between the first device sending the first frame and the first device receiving the second frame; obtaining information indicating time delays associated with multiple second devices, wherein each of the time delays is between corresponding reception of the first frame and the second frame by a corresponding second device among the multiple second devices; and obtaining a position of the STA based on the time period, the time delays associated with the multiple second devices, and a signal propagation time between the first device and each of the multiple second devices.

[0186] Aspect 18: According to the method described in Aspect 17, the method also includes: in response to the position of the STA being within an area or a structure, enabling one or more services for the STA; or in response to the position of the STA being outside the area or the structure, disabling the one or more services for the STA.

[0187] Aspect 19: A method according to any one or more of Aspects 17 to 18, wherein the first frame includes a quality of service (QoS) empty frame or a ready to send (RTS) frame, and the second frame includes an acknowledgment (ACK) frame in response to the QoS empty frame or a clear to send (CTS) frame in response to the RTS frame.

[0188] Aspect 20: A method according to any one or more of Aspects 17 to 18, wherein the first frame includes one of a single-user (SU) physical layer protocol data unit (PPDU) or a multi-user (MU) PPDU sent over the entire bandwidth of the wireless channel, and the second frame includes an acknowledgment (ACK) frame or a block ACK (BA) frame received over the entire bandwidth of the wireless channel.

[0189] Aspect 21: A method according to any one or more of aspects 17 to 20, wherein the first device includes a first access point (AP) associated with the STA, and the plurality of second devices include a plurality of corresponding passive listening devices not associated with the STA.

[0190] Aspect 22: The method according to aspect 21, wherein obtaining the time delay comprises: receiving a third frame from each second device of the plurality of second devices, the third frame indicating a respective time delay associated with the respective second device.

[0191] Aspect 23: A method according to any one or more of Aspects 17 to 22, wherein the first device includes a network entity, one of the second devices includes a first access point (AP) associated with the STA, and the other second devices include a corresponding second AP not associated with the STA.

[0192] Aspect 24: The method according to Aspect 23, wherein obtaining the position of the STA comprises: receiving coordinates of the STA relative to coordinates of the first device from the network entity.

[0193] Aspect 25: According to the method described in any one or more of Aspects 17 to 24, the method also includes: assigning a sequence number to the first frame; sending an indication of the sequence number to each of the multiple second devices; and sending an instruction to each of the multiple second devices to report the arrival time (TOA) timestamps of all first frames carrying the indicated sequence number and report the TOA timestamps of all second frames in response to the first frame.

[0194] Aspect 26: The method according to any one or more of aspects 17 to 25, wherein the position of the STA is obtained independent of a time period or time delay associated with the STA.

[0195] Aspect 27: A method according to any one or more of Aspects 17 to 26, wherein the time period is associated with the end of the sending of the first frame and the start of the receiving of the second frame; and each of the time delays is associated with the end of the receiving of the first frame and the start of the receiving of the second frame by the corresponding second device among the multiple second devices.

[0196] Aspect 28: A method according to any one or more of Aspects 17 to 27, wherein the time period is equal to the sum of the signal propagation time from the first device to the STA, the short interframe space (SIFS) duration associated with the STA, and the signal propagation time from the STA to the first device; and the corresponding time delay associated with the corresponding second device is equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the corresponding second device minus the signal propagation time from the first device to the second device.

[0197] Aspect 29: A method according to Aspect 28, wherein obtaining the position of the STA includes: obtaining a first relationship between the time period and the difference between the coordinates of the STA and the coordinates of the first device; for each second device among the multiple second devices, obtaining a second relationship between the corresponding time delay associated with the corresponding second device and the difference between the coordinates of the STA and the coordinates of the corresponding second device; obtaining the coordinates of the multiple second devices; and for each corresponding second device among the multiple second devices, obtaining the coordinates of the STA based on trilateral measurement of the first relationship and the second relationship.

[0198] Aspect 30: According to the method described in Aspect 29, the method also includes: for each corresponding second device among the multiple second devices, obtaining the SIFS duration associated with the STA based on the first relationship and the second relationship; and sending an indication of the SIFS duration to the STA.

[0199] Aspect 31: A device for wireless communication, the device comprising: a component for sending a first frame to a wireless station (STA); a component for receiving a second frame from the STA, the second frame being in response to the first frame; a component for obtaining information indicating a time period between the device sending the first frame and the device receiving the second frame; a component for obtaining information indicating time delays associated with a plurality of second devices, wherein each of the time delays is between corresponding reception of the first frame and the second frame by a corresponding second device among the plurality of second devices; and a component for obtaining a position of the STA based on the time period, the time delays associated with the plurality of second devices, and a signal propagation time between the device and each of the plurality of second devices.

[0200] Aspect 32: A non-transitory computer-readable storage medium storing instructions which, when executed by one or more processors of a device, cause the device to perform one or more operations according to any one or more of aspects 17 to 30.

[0201] As used herein, a phrase referring to "at least one of" or "one or more of" a list of items refers to any combination of those items, including single members. For example, "at least one of a, b, or c" is intended to cover the following possibilities: only a, only b, only c, a combination of a and b, a combination of a and c, a combination of b and c, and a combination of a, b, and c.

[0202] The various illustrative components, logic, logic blocks, modules, circuits, operations, and algorithmic processes described in conjunction with the specific implementations disclosed herein may be implemented as electronic hardware, firmware, software, or a combination of hardware, firmware, or software, including the structures disclosed in this specification and their structural equivalents. This interchangeability of hardware, firmware, and software has been generally described in terms of their functionality and exemplified in the various illustrative components, blocks, modules, circuits, and processes described above. Whether such functionality is implemented in hardware, firmware, or software depends on the specific application and the design constraints imposed on the overall system.

[0203] Various modifications to the specific implementations described in this disclosure will be apparent to those of ordinary skill in the art, and the general principles defined herein may be applied to other specific implementations without departing from the spirit or scope of the disclosure. Therefore, the claims are not intended to be limited to the specific implementations shown herein, but are to be consistent with the broadest scope consistent with the disclosure, the principles and novel features disclosed herein.

[0204] Additionally, various features described in this specification in the context of separate implementations may also be implemented in combination in a single implementation. Conversely, individual features described in the context of a single implementation may also be implemented in multiple implementations individually or in any suitable subcombination. Thus, although features may be described above as functioning in a particular combination, and even initially claimed as such, one or more features from a claimed combination may in some cases be deleted from the combination, and a claimed combination may be directed to a subcombination or a variation of a subcombination.

[0205] Similarly, although operations are depicted in a specific order in the figure, this should not be understood as requiring such operations to be performed in the specific order shown or in a sequential order, or to perform all illustrated operations to achieve the desired result. In addition, the accompanying drawings may schematically depict one or more example processes in the form of a flow chart or a flow diagram. However, other operations not depicted may be incorporated into the example processes schematically illustrated. For example, one or more additional operations may be performed before, after, simultaneously or between any operations in the illustrated operations. In some environments, multitasking and parallel processing may be advantageous. In addition, the separation of each system component in the specific implementation described above should not be understood as requiring such separation in all specific implementations, but it should be understood as the described program components and system can usually be integrated together in a single software product, or be packaged in multiple software products.

Claims

1. A first device, comprising: at least one processor; and at least one memory communicatively coupled to the at least one processor and storing processor-readable code that, when executed by the at least one processor, is configured to: Send the first frame to the wireless station (STA); receiving a second frame from the STA, the second frame being responsive to the first frame; Obtaining information indicating a time period between when the first device sends the first frame and when the first device receives the second frame; obtaining information indicating time delays associated with a plurality of second devices, wherein each of the time delays is between respective reception of the first frame and the second frame by a respective second device of the plurality of second devices; as well as The location of the STA is obtained based at least in part on the time period, the time delay associated with the plurality of second devices, and a signal propagation time between the first device and each of the plurality of second devices.

2. The first device of claim 1, wherein executing the processor readable code is further configured to: In response to the location of the STA being within an area or structure, enabling one or more services for the STA; or In response to the location of the STA being outside the area or the structure, the one or more services for the STA are disabled.

3. The first device of claim 1, wherein the first frame comprises a quality of service (QoS) null frame or a ready to send (RTS) frame, and the second frame comprises an acknowledgment (ACK) frame in response to the QoS null frame or a clear to send (CTS) frame in response to the RTS frame.

4. The first device of claim 1 , wherein the first frame comprises one of a single-user (SU) physical layer protocol data unit (PPDU) or a multi-user (MU) PPDU sent over an entire bandwidth of a wireless channel, and the second frame comprises an acknowledgment (ACK) frame or a block ACK (BA) frame received over the entire bandwidth of the wireless channel.

5. The first device of claim 1, wherein the first device comprises a first access point (AP) associated with the STA, and the plurality of second devices comprises a plurality of respective passive listening devices not associated with the STA.

6. The first device of claim 5, wherein executing the processor readable code to obtain the time delay is further configured to: A third frame is received from each second device of the plurality of second devices, the third frame indicating a respective time delay associated with the respective second device. 7 . The first device of claim 1 , wherein one or both of the information indicating the time delays associated with the plurality of second devices or the locations of the STAs are obtained from a network entity.

8. The first device of claim 7, wherein executing the processor readable code to obtain the location of the STA is further configured to: Coordinates of the STA relative to coordinates of the first device are obtained from the network entity.

9. The first device of claim 1, wherein executing the processor readable code is further configured to: assigning a sequence number to the first frame; sending an indication of the sequence number to each second device of the plurality of second devices; and An instruction is sent to each of the plurality of second devices to report a time of arrival (TOA) timestamp of all first frames carrying the indicated sequence number and to report a TOA timestamp of all second frames responsive to the first frame.

10. The first device of claim 1, wherein the location of the STA is obtained independent of a time period or a time delay associated with the STA.

11. The first device according to claim 1, wherein: The time period is associated with an end of the transmission of the first frame and a start of the reception of the second frame; and Each of the time delays is associated with an end of the reception of the first frame and a start of the reception of the second frame by the corresponding second device of the plurality of second devices.

12. The first device according to claim 1, wherein: The time period is equal to the sum of a signal propagation time from the first device to the STA, a short interframe space (SIFS) duration associated with the STA, and a signal propagation time from the STA to the first device; and The corresponding time delay associated with the corresponding second device is equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the corresponding second device minus the signal propagation time from the first device to the second device.

13. The first device of claim 12, wherein executing the processor readable code to obtain the location of the STA is further configured to: Obtaining a first relationship between the time period and a difference between the coordinates of the STA and the coordinates of the first device; For each second device of the plurality of second devices, obtaining a second relationship between the corresponding time delay associated with the corresponding second device and a difference between the coordinates of the STA and the coordinates of the corresponding second device; obtaining the coordinates of the plurality of second devices; as well as For each corresponding second device among the plurality of second devices, the coordinates of the STA are obtained based on trilateration of the first relationship and the second relationship.

14. The first device of claim 13, wherein executing the processor readable code is further configured to: For each corresponding second device among the plurality of second devices, obtaining the SIFS duration associated with the STA based on the first relationship and the second relationship; and An indication of the SIFS duration is sent to the STA.

15. The first device of claim 1, wherein executing the processor readable code is further configured to: embedding a signal or value in said first frame; sending an indication of the signal or the value to each second device of the plurality of second devices; and Instructions are sent to each of the plurality of second devices to report time of arrival (TOA) timestamps of all first frames carrying the embedded signal or value and to report TOA timestamps of all second frames responsive to the first frames carrying the embedded signal or value.

16. A first device according to claim 15, wherein the embedded signal or value is indicated by one of a reserved or unused bit of a preamble of the first frame, a reserved or unused bit of a medium access control (MAC) header of the first frame, or a reserved or unused bit of an element, field or subfield following the MAC header of the first frame.

17. A method for wireless communication by a first device, the method comprising: Send the first frame to the wireless station (STA); receiving a second frame from the STA, the second frame being responsive to the first frame; Obtaining information indicating a time period between when the first device sends the first frame and when the first device receives the second frame; obtaining information indicating time delays associated with a plurality of second devices, wherein each of the time delays is between respective reception of the first frame and the second frame by a respective second device of the plurality of second devices; as well as The location of the STA is obtained based at least in part on the time period, the time delay associated with the plurality of second devices, and a signal propagation time between the first device and each of the plurality of second devices.

18. The method according to claim 17, further comprising: In response to the location of the STA being within an area or a structure, enabling one or more services for the STA; or In response to the location of the STA being outside the area or the structure, the one or more services for the STA are disabled.

19. The method of claim 17, wherein the first frame comprises a quality of service (QoS) null frame or a ready to send (RTS) frame, and the second frame comprises an acknowledgement (ACK) frame in response to the QoS null frame or a clear to send (CTS) frame in response to the RTS frame.

20. The method of claim 17, wherein the first frame comprises one of a single-user (SU) physical layer protocol data unit (PPDU) or a multi-user (MU) PPDU transmitted over an entire bandwidth of a wireless channel, and the second frame comprises an acknowledgement (ACK) frame or a block ACK (BA) frame received over the entire bandwidth of the wireless channel.

21. The method of claim 17, wherein the first device comprises a first access point (AP) associated with the STA, and the plurality of second devices comprises a plurality of respective passive listening devices not associated with the STA.

22. The method of claim 21 , wherein obtaining the time delay comprises: A third frame is received from each second device of the plurality of second devices, the third frame indicating a respective time delay associated with the respective second device.

23. The method of claim 17, wherein the first device comprises a network entity, one of the second devices comprises a first access point (AP) associated with the STA, and the other second devices comprise a corresponding second AP not associated with the STA.

24. The method of claim 23, wherein obtaining the position of the STA comprises: Coordinates of the STA relative to coordinates of the first device are received from the network entity.

25. The method of claim 17, further comprising: assigning a sequence number to the first frame; sending an indication of the sequence number to each second device of the plurality of second devices; as well as An instruction is sent to each of the plurality of second devices to report a time of arrival (TOA) timestamp of all first frames carrying the indicated sequence number and to report a TOA timestamp of all second frames responsive to the first frame.

26. The method of claim 17, wherein the location of the STA is obtained independent of a time period or time delay associated with the STA.

27. The method of claim 17, wherein: The time period is associated with an end of the transmission of the first frame and a start of the reception of the second frame; and Each of the time delays is associated with an end of the reception of the first frame and a start of the reception of the second frame by the corresponding second device of the plurality of second devices.

28. The method of claim 17, wherein: The time period is equal to the sum of a signal propagation time from the first device to the STA, a short interframe space (SIFS) duration associated with the STA, and a signal propagation time from the STA to the first device; and The corresponding time delay associated with the corresponding second device is equal to the sum of the signal propagation time from the first device to the STA, the SIFS duration associated with the STA, and the signal propagation time from the STA to the corresponding second device minus the signal propagation time from the first device to the second device.

29. An apparatus, comprising: A means for sending a first frame to a wireless station (STA); means for receiving a second frame from the STA, the second frame being responsive to the first frame; means for obtaining information indicating a time period between the device transmitting the first frame and the device receiving the second frame; means for obtaining information indicative of time delays associated with a plurality of second devices, wherein each of the time delays is between respective reception of the first frame and the second frame by a respective second device of the plurality of second devices; and means for obtaining a location of the STA based on the time period, the time delay associated with the plurality of second devices, and a signal propagation time between the apparatus and each of the plurality of second devices.

30. A non-transitory computer-readable storage medium storing processor-readable code that, when executed by one or more processors of a device, causes the device to perform operations comprising: Send the first frame to the wireless station (STA); receiving a second frame from the STA, the second frame being responsive to the first frame; obtaining information indicating a time period between the device sending the first frame and the device receiving the second frame; obtaining information indicating time delays associated with a plurality of second devices, wherein each of the time delays is between respective reception of the first frame and the second frame by a respective second device of the plurality of second devices; and The location of the STA is obtained based on the time period, the time delay associated with the plurality of second devices, and a signal propagation time between the apparatus and each of the plurality of second devices.

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