SECURED TIME OF FLIGHT MEASUREMENT

Computing readable media, apparatuses, and methods for secure time of flight measurements are disclosed. An apparatus comprising processing circuitry is disclosed. The processing circuitry configured to encode a fine time measurement (FTM) request. The processing circuitry further configured to decode a FTM response from the responder, where the FTM response is to be received at the wireless device at a time t2, and generate a symmetric key from a private encryption key of the wireless device and the public encryption key of the responder. The processing circuitry further configured to transmit an acknowledgement to the FTM response, the acknowledgement is transmitted at time t3, and decode an encrypted FTM frame from the responder with the symmetric key, the decrypted FTM message comprising a time t1 when the FTM response was to be transmitted and a time t4 when the acknowledgement to the FTM response was to be received.

TECHNICAL FIELD

Embodiments pertain to wireless networks and wireless communications. Some embodiments relate to wireless local area networks (WLANs) and Wi-Fi networks including networks operating in accordance with the IEEE 802.11 family of standards. Some embodiments relate to IEEE 802.11ax/mc. Some embodiments relate to methods, computer readable media, and apparatus for secured time of flight measurements. Some embodiments relate to fine timing measurements (FTM) that are secured.

BACKGROUND

Efficient use of the resources of a wireless local-area network (WLAN) is important to provide bandwidth and acceptable response times to the users of the WLAN. However, often there are many devices trying to share the same resources and some devices may be limited by the communication protocol they use or by their hardware bandwidth. Moreover, wireless devices may need to operate with both newer protocols and with legacy device protocols.

DESCRIPTION

FIG. 1illustrates a WLAN100in accordance with some embodiments. The WLAN100may comprise a basis service set (BSS)100that may include a master station102, which may be an AP, a plurality of high-efficiency wireless (e.g., IEEE 802.11ax) (HE) stations104, and a plurality of legacy (e.g., IEEE 802.1 in/ac) devices106.

The master station102may be an AP using the IEEE 802.11 to transmit and receive. The master station102may be a base station. The master station102may use other communications protocols as well as the IEEE 802.11 protocol. The IEEE 802.11 protocol may be IEEE 802.11ax. The IEEE 802.11 protocol may include using orthogonal frequency division multiple-access (OFDMA), time division multiple access (TDMA), and/or code division multiple access (CDMA). The IEEE 802.11 protocol may include a multiple access technique. For example, the IEEE 802.11 protocol may include space-division multiple access (SDMA) and/or multiple-user multiple-input multiple-output (MU-MIMO). There may be more than one master station102that is part of an extended service set (ESS). A controller (not illustrated) may store information that is common to the more than one master stations102.

The legacy devices106may operate in accordance with one or more of IEEE 802.11 a/b/g/n/ac/ad/af/ah/aj/ay, or another legacy wireless communication standard. The legacy devices106may be STAs or IEEE STAs. The HE STAs104may be wireless transmit and receive devices such as cellular telephone, portable electronic wireless communication devices, smart telephone, handheld wireless device, wireless glasses, wireless watch, wireless personal device, tablet, or another device that may be transmitting and receiving using the IEEE 802.11 protocol such as IEEE 802.11ax or another wireless protocol. In some embodiments, the HE STAs104may be termed high efficiency (HE) stations.

The master station102may communicate with legacy devices106in accordance with legacy IEEE 802.11 communication techniques. In example embodiments, the master station102may also be configured to communicate with HE STAs104in accordance with legacy IEEE 802.11 communication techniques.

In some embodiments, a HE frame may be configurable to have the same bandwidth as a channel. The HE frame may be a physical Layer Convergence Procedure (PLCP) Protocol Data Unit (PPDU).

The bandwidth of a channel may be 20 MHz, 40 MHz, or 80 MHz, 160 MHz, 320 MHz contiguous bandwidths or an 80+80 MHz (160 MHz) non-contiguous bandwidth. In some embodiments, the bandwidth of a channel may be 1 MHz, 1.25 MHz, 2.03 MHz, 2.5 MHz, 4.06 MHz, 5 MHz and 10 MHz, or a combination thereof or another bandwidth that is less or equal to the available bandwidth may also be used. In some embodiments the bandwidth of the channels may be based on a number of active data subcarriers. In some embodiments the bandwidth of the channels is based on 26, 52, 106, 242, 484, 996, or 2×996 active data subcarriers or tones that are spaced by 20 MHz. In some embodiments the bandwidth of the channels is 256 tones spaced by 20 MHz. In some embodiments the channels are multiple of 26 tones or a multiple of 20 MHz. In some embodiments a 20 MHz channel may comprise 242 active data subcarriers or tones, which may determine the size of a Fast Fourier Transform (FFT). An allocation of a bandwidth or a number of tones or sub-carriers may be termed a resource unit (RU) allocation in accordance with some embodiments.

A HE frame may be configured for transmitting a number of spatial streams, which may be in accordance with MU-MIMO and may be in accordance with OFDMA. In other embodiments, the master station102, HE STA104, and/or legacy device106may also implement different technologies such as code division multiple access (CDMA) 2000, CDMA 2000 1×, CDMA 2000 Evolution-Data Optimized (EV-DO), Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Long Term Evolution (LTE), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), BlueTooth®, or other technologies.

Some embodiments relate to HE communications. In accordance with some IEEE 802.11 embodiments, e.g, IEEE 802.11ax embodiments, a master station102may operate as a master station which may be arranged to contend for a wireless medium (e.g., during a contention period) to receive exclusive control of the medium for an HE control period. In some embodiments, the HE control period may be termed a transmission opportunity (TXOP). The master station102may transmit a HE master-sync transmission, which may be a trigger frame or HE control and schedule transmission, at the beginning of the HE control period. The master station102may transmit a time duration of the TXOP and sub-channel information. During the HE control period, HE STAs104may communicate with the master station102in accordance with a non-contention based multiple access technique such as OFDMA or MU-MIMO. This is unlike conventional WLAN communications in which devices communicate in accordance with a contention-based communication technique, rather than a multiple access technique. During the HE control period, the master station102may communicate with HE stations104using one or more HE frames. During the HE control period, the HE STAs104may operate on a sub-channel smaller than the operating range of the master station102. During the HE control period, legacy stations refrain from communicating. The legacy stations may need to receive the communication from the master station102to defer from communicating.

In accordance with some embodiments, during the TXOP the HE STAs104may contend for the wireless medium with the legacy devices106being excluded from contending for the wireless medium during the master-sync transmission. In some embodiments the trigger frame may indicate an uplink (UL) UL-MU-MIMO and/or UL OFDMA TXOP. In some embodiments, the trigger frame may include a DL UL-MU-MIMO and/or DL OFDMA with a schedule indicated in a preamble portion of trigger frame.

In some embodiments, the multiple-access technique used during the HE TXOP may be a scheduled OFDMA technique, although this is not a requirement. In some embodiments, the multiple access technique may be a time-division multiple access (TDMA) technique or a frequency division multiple access (FDMA) technique. In some embodiments, the multiple access technique may be a space-division multiple access (SDMA) technique. In some embodiments, the multiple access technique may be a Code division multiple access (CDMA).

The master station102may also communicate with legacy stations106and/or HE stations104in accordance with legacy IEEE 802.11 communication techniques. In some embodiments, the master station102may also be configurable to communicate with HE stations104outside the HE TXOP in accordance with legacy IEEE 802.11 communication techniques, although this is not a requirement.

In some embodiments the HE station104may be a “group owner” (GO) for peer-to-peer modes of operation. A wireless device may be a HE station102or a master station102.

In some embodiments, the HE station104and/or master station102may be configured to operate in accordance with IEEE 802.11mc.

In example embodiments, the HE station104and/or the master station102are configured to perform the methods and functions described herein in conjunction withFIGS. 1-11.

FIG. 2illustrates a method200of FTM in accordance with some embodiments. Illustrated inFIG. 2is AP/Responder202and STA204. The AP/responder202may be a master station102or a HE station104. The STA204may be a master station102or a HE station104. The method200begins at time t1206with the AP/responder202transmitting a message MO208to the STA204. The AP/responder202may record time t1206. The message MO208may be a FTM response. Prior to time t1the STA204may have transmitted a FTM request to the AP/responder202. The STA204may receive the message MO208at time t2210. The STA204may record the time t2210.

The method200continues at time t3212with the STA204transmitting an acknowledgment (ACK)214to the AP/responder202. The ACK214may be received by the AP/responder202at time t4216. The STA204may record the time t3212. The AP/responder202may record time t4216.

The method200continues at time t5220with the AP/responder202transmitting message m1(t1,t4)218. The message m1comprises time t1206and time t4216. The message m1(t1, t4)218may be received at time t6222by the STA204.

The method200continues at operation224with the STA204determining a distance from AP/responder202. The STA204may determine the distance based on equation (1): round trip time (RTT)=(t4−t1)−(t3−t2). The STA204may perform the FTM method200with one or more additional AP/responders202. In some embodiments, the values of time t1206and time t4216are transmitted over the wireless medium unencrypted.

FIG. 3illustrates a STA performing multiple FTMs and an adversary300in accordance with some embodiments. Illustrated inFIG. 3is FTM responders302, STA304, hyperboles310, and adversary308. Each of STA304, FTM responders302, and adversary308may be either a master station102or HE station104.

The STA304may have performed three FTMs with FTM responder1302.1, FTM responder2302.2, and FTM responder3302.3. The adversary308may determine from the FTM between the STA304and the FTM responder302.1that the STA304is on hyperbole310.1. The adversary308may determine from the FTM between the STA304and the FTM responder302.2that the STA304is on hyperbole310.2. The adversary308may determine from the FTM between the STA304and the FTM responder302.3that the STA304is on hyperbole310.3.

The adversary308can determine the location of the STA304at location305based on intercepting the three FTMs between STA304and the three FTM responders302. The time-tags transmitted in the packets may be unencrypted enabling the adversary308to determine the location of the STA304.

The adversary308may passively intercept the three FTMs between STA304and the three FTM responders302. In some embodiments, the adversary308may be an active and trigger an attack to falsely modify the position which the STA304calculates. For example, the adversary308may respond as if it is one of the FTM responders302. The user of the STA304may have comprised security because of the adversary308learning of the location of the STA304.

FIG. 4illustrates a method400of secured FTM in accordance with some embodiments. Illustrated inFIG. 4is AP/responder402and STA404. Each of AP/responder402and STA404may be master station102or HE station104. The AP/responder402comprises a public key450, private key452, and symmetric (symm) key454. The STA404comprises a public key460, private key462, and symm key464.

The method400optionally begins at operation406with the AP/responder402generating a public key450and a secret or private key452, which may be based on a random number. In some embodiments, the AP/responder402may have already generated a public key450and a private key452and stored the keys. The method400optionally continues at operation408with the STA404generating a public key460and a secret or private key462, which may be based on a random number.

The method400continues with the STA404transmitting FTM request with STA public key410, e.g. public key4060. For example, FTM request with STA public key410may be the same or similar as FTM request frame500, which may include public key subelement514. The public key460of STA404may be a public key subelement600.

The method400continues with symmetric key generation414by the AP/responder402, symm key454. Symmetric key generation414may be performed in parallel to performing other operations, e.g. transmitting FTM response with AP public key416. The AP/responder402may use Elliptic Curve Diffie-Hellman method to generate the symmetric key454. The symmetric key454may be based on the public key460of STA404and the secret key or private key452of AP/responder402. The symmetric key454generation414may be time consuming relative to the time that packets410,416,424,428, and430can be encoded, transmitted, and decoded. The AP/responder402may store the symm key454with an identification of the STA404such as an association identification (AID).

In some embodiments, a public key crypto-system may be used such as N-th Degree Truncated Polynomial Ring (NTRU) or Rivest, Shamir, and Adelman (RSA) rather than Elliptic curve Diffie-Hellman (ECDH).

The method400continues with the AP/responder402transmitting FTM response with AP public key (e.g.,450)416. The AP/responder402may record time t1412when FTM response with AP public key416is transmitted by the AP/responder402. FTM response with AP public key416may be an FTM frame700with the public key (e.g.,450) of AP/responder402being a public key subelement726.

The method400continues with STA404receiving FTM response with AP public key416at time t2418. STA404may store the t2418.

The method400continues with symmetric key generation420by the STA404. The symmetric key generation420may be performed in parallel to other operations performed by STA404. The symmetric key generation420may use the public key450of the AP/responder and the private key462of the STA404to generate the symmetric key454. The symmetric key454may be used to decrypt data encrypted by symmetric key454.

The method400continues with the STA404transmitting acknowledgement (ACK)424at time t3422. STA404may store the time t3422.

The method400continues with AP/Responder402receiving ACK424at time t4426. The AP/Responder402may store time t4426.

The method400continues with the AP/Responder402transmitting encrypted FTM428. The symmetric key generation414is completed before the AP/Responder402transmits the encrypted FTM428. The AP/responder402encrypts the encrypted FTM428with the symmetric key454. The AP/responder402may encrypt a media access control (MAC) portion of the encrypted FTM428. The AP/responder402may set a field of a frame control field (e.g.,800) of encrypted FTM428that indicates that encrypted FTM428is encrypted, e.g., a protected frame802field of a frame control field800.

The encrypted FTM428may be a FTM frame700with a frame control field800with a protected frame802field indicating that the FTM frame700is encrypted. The encrypted FTM428includes TI412and T4426.

The method400continues with the STA404receiving encrypted FTM428. The STA404needs to complete symmetric key464generation420to decrypt encrypted FTM428.

The method400continues with STA404transmitting an ACK430to AP/Responder402. The AP/responder402may receive the ACK430and determine that encrypted FTM428was received by STA404.

In some embodiments, STA404receives the public key450of the AP/responder402in a beacon from the AP/responder402. In some embodiments, STA404receives the public key450of the AP/responder402in a different packet, e.g. from another AP/responder or a central server. The symmetric key generation420may begin at any time after the STA404generates a public key460and a private key452for the STA404and receives the public key450of the AP/responder402.

The AP/responder402and/or the STA404may store the symmetric key450,460, respectively, for use in another communication with one another.

In some embodiments, the FTM request with STA public key410may include a field that indicates that the STA404already has the public key of the AP/responder402, e.g. have public key515ofFIG. 5. The AP/responder402may determine not to transmit the public key450in FTM response with AP public key416if the STA404indicates it already has the public key450of the AP/Responder402.

In some embodiments, the AP/responder402may already have the public key460of the STA404. For example, the AP/responder402may receive the public key460of the STA404from another AP or a central server.

In some embodiments, the STA404and/or AP/responder402may use optimized elliptical curve libraries to determine the symmetric keys464,454, respectively. In some embodiments, the symmetric key464,454, respectively, may be generated by the STA404and/or AP/responder402in 20 ms.

The encrypted FTM428may only be decrypted using the symmetric key464. The symmetric key454can only be generated with the public key460of STA404and private key452of AP/Responder402, or with public key450of AP/responder402and private key462of STA404. So, only the STA404and the AP/responder402can decrypt encrypted FTM428. The location of STA404may be keep confidential by encrypting the encrypted FTM428. In some embodiments, a different set of messages may be exchanged to determine the location of the STA404, but in each case, timing from the AP/Responder402is encrypted and transmitted to the STA404to enable the STA404to confidentially determine the location of the STA404. For example, time of flight (ToF) may be equal to ((t4−t1)−(t3−t2))/2, and the distance from AP/responder402and STA404may be (ToF/2) times speed of light. The STA404can then determine the range from the AP/responder402and use triangulation with a other AP/responders402to determine a location. In some embodiments, the times t1412, t2418, t3422, and t4426may be determined differently. For example, one or more of FTM response with AP public key416, ACK424, and encrypted FTM428may be a different type of packet type. Moreover, in some embodiments, the AP/responder402may initiate the ToF method with the STA404.

FIG. 5illustrates a FTM request frame500in accordance with some embodiments. The FTM request frame500includes category502, public action504, trigger506, location configuration information (LCI) measurement request508, location civic measurement request510, FTM parameters512, public key sub-element514, and have public key515.

The category502may be set to a value indicating a FTM action frame. The public action504may be 32 to indicate it is a FTM request. The trigger506may be set to 1 indicates that the initiating STA requests that the responding STA start or continue sending Fine Timing Measurement frames. The Trigger field set to 0 indicates that the initiating STA requests that the responding STA stop sending Fine Timing Measurement frames. The LCI measurement request508is optional and if present contains a measurement request element that indicates parameters for a report. The location civic measurement request510is optional, and, if present, contains a measurement request element. The FTM parameters512is present in the initial FTM request frame. If present, it contains FTM parameters element. The public key sub-element514is optional, and, if present, may be the same or similar as600ofFIG. 6. Have public key515may indicate whether or not the transmitting wireless device already has the public key515of the receiving wireless device.

FIG. 6illustrates a public key subelement600in accordance with some embodiments. The public key subelement600may include an element identification (ID)602, which may identify the element as public key sub-element, length604, which may be a length of the public key606, and public key606, which may be variable in length. In some embodiments, the public key subelement600may have different fields.

In some embodiments one or more of the fields may not be present. Additionally, in some embodiments, one or more additional fields may be present.

FIG. 7illustrates a FTM frame700in accordance with some embodiments. The FTM frame700may include one or more of the following fields. A category702, a public action704, a dialog token706, a follow up dialog token708, time of department (TOD)710, time of arrival (TOA)712, TOD error714, TOA error716, FTM synchronization information718, LCI report720, location civic report722, fine timing measurement parameters724, public key subelement726.

The category702may be set to a value indicating a FTM action frame. The public action504may indicate it is a FTM measure frame. Dialog token706is a token chosen by the responding STA to identify the FTM frame as the first of a pair of frames. Follow up dialog token708is token to indicate it is a follow up to the FTM frame. TOD710time of department. TOA712time of arrival. TOD error714indicates error parameters. TOA error716indicates error parameters. FTM synchronization information718may include a FTM synchronization information element. LCI report720may be a location configuration information measurement report. Location civic report722is a measurement report element. FTM parameters724may be parameters for FTM measurements.

FIG. 8illustrates a frame control field800in accordance with some embodiments.FIG. 8illustrates frame control field800which may be a frame control field for FTM frame700and/or FTM request frame500. The frame control field800includes a protected frame822, which may be one bit and indicates whether the FTM message is encrypted. In some embodiments, the frame control field800includes one or more of the following fields: protocol version804, type806, subtype808, to distribution system (DS)810, from DS812, more fragments814, retry816, power management818, more data820, protected frame822, and +HTC order824. The following describes embodiments of the frame control field800. The protocol version804may indicate a protocol version. The type806and subtype808may identify the function of the frame. To DS810and from DS812may indicate source and destination of a frame. More fragments814may indicate if there are additional media access control fragments in a next frame. Retry816indicates that the frame is a retransmission. The power management subfield818is used to indicate a power management mode of a station. The more data820subfield may indicate more data or that a station is power save mode. The +HTC/order824subfield may indicate a type of service class. In some embodiments, the frame control field800may be in accordance with one or more communication protocols such as IEEE 802.11mc.

FIG. 9illustrates a method900for secured time of flight measurement in accordance with some embodiments. The method900begins at operation902with encode a fine time measurement (FTM) request comprising a public encryption key of the wireless device for transmission to a responder. For example, STA404may encode FTM request with STA public key410.

Optionally, the method900includes operation with configuring the wireless device to transmit the FTM request to a responder. For example, an apparatus of STA404may configure the STA404to transmit the FTM request with STA public key410.

The method900continues at operation906with decoding a FTM response from the responder, the FTM response comprising a public encryption key of the responder, wherein the FTM response is to be received at the wireless device at a time t2. For example, STA404may receive FTM response with AP public key416from AP/responder402with public key450.

The method900continues at operation908with generating a symmetric key from a private encryption key of the wireless device and the public encryption key of the responder. For example, STA404may generate symmetric key464.

The method900continues at operation910with configuring the wireless device to transmit an acknowledgement to the FTM response, wherein the acknowledgement is to be transmitted at a time t3. For example, an apparatus of STA404may configure STA404to transmit ACK424at time t3.

The method900continues at operation912with decoding an encrypted FTM frame from the responder. For example, STA404may decode encrypted FTM428from AP/Responder402.

The method900continues at operation914with decrypting a MAC portion of the encrypted FTM frame with the symmetric key, the decrypted FTM message comprising a time t1when the FTM response was to be transmitted and a time t4when the acknowledgement to the FTM response was to be received. For example, STA404may decrypt encrypted FTM428which comprises times t1412and t4426.

The method900continues at operation916with determining a distance of the wireless device from the responder based on time t1, time t2, time t3, and time t4. For example, STA404may use the times t1412, t2418, t3422, and t4426to determine a distance from AP/responder402to the STA404.

FIG. 10illustrates a method1000for secured time of flight measurement in accordance with some embodiments. The method1000begins at operation1002with decoding a FTM request comprising a public encryption key of a second wireless device. For example, AP/responder402may decode FTM request with STA public key410, which may include public key460of STA404.

The method1000continues at operation1004with generating a symmetric key from a private encryption key of the first wireless device and the public encryption key of the second wireless device. For example, AP/responder402may generate symmetric key454with private key452and public key460.

The method1000continues at operation1006with encoding a FTM response to the second wireless device, the FTM response comprising a public encryption key of the first wireless device. For example, AP/responder402may encode FTM response with AP public key416, which may include public key450.

The method1000continues at operation1008with configuring the wireless device to transmit the FTM response to the second wireless device at a time t1. For example, an apparatus of the AP/responder402may configure the AP/responder402to transmit FTM response with AP public key416.

The method1000continues at operation1010with decoding an acknowledgement from the second wireless device of the FTM response, the acknowledgment to be received at a time t4. For example, AP/responder402may decode ACK424received at time t4426.

The method1000continues at operation1014with encoding an encrypted FTM with encrypted t1and t4. For example, AP/responder402may encode encrypted FTM428.

The method1000continues at operation1016with configuring the first wireless device to transmit the encrypted FTM to the second wireless device. For example, an apparatus of AP/responder402may configure the AP/responder402to transmit the encrypted FTM428.

Machine (e.g., computer system)1100may include a hardware processor1102(e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory1104and a static memory1106, some or all of which may communicate with each other via an interlink (e.g., bus)1108. The machine1100may further include a display device1110, an input device1112(e.g., a keyboard), and a user interface (UI) navigation device1114(e.g., a mouse). In an example, the display device1110, input device1112and UI navigation device1114may be a touch screen display. The machine1100may additionally include a mass storage (e.g., drive unit)1116, a signal generation device1118(e.g., a speaker), a network interface device1120, and one or more sensors1121, such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor. The machine1100may include an output controller1128, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.). In some embodiments the processor1102and/or instructions1124may comprise processing circuitry and/or transceiver circuitry.

The storage device1116may include a machine readable medium1122on which is stored one or more sets of data structures or instructions1124(e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions1124may also reside, completely or at least partially, within the main memory1104, within static memory1106, or within the hardware processor1102during execution thereof by the machine1100. In an example, one or any combination of the hardware processor1102, the main memory1104, the static memory1106, or the storage device1116may constitute machine readable media.

An apparatus of the machine1100may be one or more of a hardware processor1102(e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory1104and a static memory1106, some or all of which may communicate with each other via an interlink (e.g., bus)1108.

In an example, the network interface device1120may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network1126. In an example, the network interface device1120may include one or more antennas1160to wirelessly communicate using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques. In some examples, the network interface device1120may wirelessly communicate using Multiple User MIMO techniques. The term “transmission medium” shall be taken to include any intangible medium that is capable of storing, encoding or carrying instructions for execution by the machine1100, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software.

Example 1 is an apparatus of a wireless device including: memory; and processing circuitry coupled to the memory, the processing circuitry configured to: encode a fine time measurement (FTM) request including a public encryption key of the wireless device for transmission to a responder; decode a FTM response from the responder, the FTM response including a public encryption key of the responder, where the FTM response is received at the wireless device at a time t2; generate a symmetric key from a private encryption key of the wireless device and the public encryption key of the responder; configure the wireless device to transmit an acknowledgement to the FTM response, where the acknowledgement is to be transmitted at a time t3; decode an encrypted FTM frame from the responder; decrypt a media access control (MAC) portion of the encrypted FTM frame with the symmetric key, the decrypted FTM message including a time t1when the FTM response was transmitted and a time t4when the acknowledgement to the FTM response was received; and determine a distance of the wireless device from the responder based on time t1, time t2, time t3, and time t4.

In Example 2, the subject matter of Example 1 optionally includes where the processing circuitry is configured to: generate the public encryption key of the wireless device and the private encryption key.

In Example 3, the subject matter of any one or more of Examples 1-2 optionally include where the processing circuitry is configured to: begin generating the symmetric key from the private encryption key of the wireless device and the public encryption key of the responder after time t2and complete generating the symmetric key from the private encryption key of the wireless device and the public encryption key of the responder after the time t3.

In Example 4, the subject matter of Example 3 optionally includes where the processing circuitry is configured to generate the symmetric key using an Elliptic Curve Diffie-Hellman method or a public key crypto-system.

In Example 5, the subject matter of any one or more of Examples 3-4 optionally include where the processing circuitry is configured to generate the symmetric key in a parallel process.

In Example 6, the subject matter of any one or more of Examples 1-5 optionally include where the processing circuitry is configured to: configure the wireless device to transmit an acknowledgement of the encrypted FTM message.

In Example 7, the subject matter of any one or more of Examples 1-6 optionally include where the processing circuitry is configured to: perform a second FTM measurement with the responder using the symmetric key.

In Example 8, the subject matter of any one or more of Examples 1-7 optionally include where the processing circuitry is further configured to: configure the wireless device to transmit the FTM request to the responder in accordance with one or both of orthogonal frequency division multiple-access (OFDMA) and multiple-user multiple-input and multiple-output (MU-MIMO).

In Example 9, the subject matter of any one or more of Examples 1-8 optionally include where the processing circuitry is configured to: decode the FTM response from the responder, where the public key of the responder is a part of a subelement, the subelement including an subelement identification, a length, and the public key, where the subelement identification identifies the subelement as a public key subelement.

In Example 10, the subject matter of any one or more of Examples 1-9 optionally include where the processing circuitry is configured to: encode the FTM request including a subelement, the subelement including a subelement identification, a length, and the public key of the wireless device, where the subelement identification identifies the subelement as a public key subelement.

In Example 11, the subject matter of any one or more of Examples 1-10 optionally include where the processing circuitry is configured to: decode the encrypted FTM frame from the responder, where a protected frame bit of a frame control field indicates the MAC portion of the encrypted FTM frame is encrypted.

In Example 12, the subject matter of any one or more of Examples 1-11 optionally include where the wireless device and the one or more stations are each one from the following group: an Institute of Electrical and Electronic Engineers (IEEE) 802.11ax access point, an IEEE 802.11ax station, an IEEE 802.11mc station, an IEEE 802.11mc access point, an IEEE 802.11 station, and an IEEE 802.11 access point.

In Example 13, the subject matter of any one or more of Examples 1-12 optionally include transceiver circuitry coupled to the processing circuitry.

In Example 14, the subject matter of Example 13 optionally includes one or more antennas coupled to the transceiver circuitry.

Example 15 is a non-transitory computer-readable storage medium that stores instructions for execution by one or more processors, the instructions to configure the one or more processors to cause an apparatus of a wireless device to: encode a fine time measurement (FTM) request including a public encryption key of the wireless device for transmission to a responder; decode a FTM response from the responder, the FTM response including a public encryption key of the responder, where the FTM response is received at the wireless device at a time t2; generate a symmetric key from a private encryption key of the wireless device and the public encryption key of the responder; configure the wireless device to transmit an acknowledgement to the FTM response, where the acknowledgement is to be transmitted at a time t3; decode an encrypted FTM frame from the responder; decrypt a media access control (MAC) portion of the encrypted FTM frame with the symmetric key, the decrypted FTM message including a time t1when the FTM response was transmitted and a time t4when the acknowledgement to the FTM response was received; and determine a distance of the wireless device from the responder based on time t1, time t2, time t3, and time t4.

In Example 16, the subject matter of Example 15 optionally includes the instructions to further configure the one or more processors to cause the apparatus to: begin generating the symmetric key from the private encryption key of the wireless device and the public encryption key of the responder after time t2and complete generating the symmetric key from the private encryption key of the wireless device and the public encryption key of the responder after the time t3.

In Example 17, the subject matter of any one or more of Examples 15-16 optionally include the instructions to further configure the one or more processors to cause the apparatus to: generate the symmetric key using an Elliptic Curve Diffie-Hellman method or a public key crypto-system.

Example 18 is a method performed by an apparatus of a wireless device, the method including: encoding a fine time measurement (FTM) request including a public encryption key of the wireless device for transmission to a responder; decoding a FTM response from the responder, the FTM response including a public encryption key of the responder, where the FTM response is received at the wireless device at a time t2: generating a symmetric key from a private encryption key of the wireless device and the public encryption key of the responder; configuring the wireless device to transmit an acknowledgement to the FTM response, where the acknowledgement is to be transmitted at a time t3; decoding an encrypted FTM frame from the responder; decrypting a media access control (MAC) portion of the encrypted FTM frame with the symmetric key, the decrypted FTM message including a time t1when the FTM response was transmitted and a time t4when the acknowledgement to the FTM response was received; and determining a distance of the wireless device from the responder based on time t1, time t2, time t3, and time t4.

In Example 19, the subject matter of Example 18 optionally includes the method further including: beginning to generate the symmetric key from the private encryption key of the wireless device and the public encryption key of the responder after time t2and complete generating the symmetric key from the private encryption key of the wireless device and the public encryption key of the responder after the time t3.

Example 20 is an apparatus of a first wireless device including: memory; and processing circuitry coupled to the memory, the processing circuitry configured to: decode a fine time measurement (FTM) request including a public encryption key of a second wireless device; generate a symmetric key from a private encryption key of the first wireless device and the public encryption key of the second wireless device; encode a FTM response to the second wireless device, the FTM response including a public encryption key of the first wireless device; configure the wireless device to transmit the FTM response to the second wireless device at a time t1; decode an acknowledgement from the second wireless device of the FTM response, the acknowledgment to be received at a time t4; encrypt t1and t4with the symmetric encryption key; encode an encrypted FTM with encrypted t1and t4; and configure the first wireless device to transmit the encrypted FTM to the second wireless device.

In Example 21, the subject matter of Example 20 optionally includes where the processing circuitry is configured to: generate the public encryption key of the first wireless device and the private encryption key of the first wireless device.

In Example 22, the subject matter of any one or more of Examples 20-21 optionally include where the processing circuitry is configured to: begin generating the symmetric key from the private encryption key of the first wireless device and the public encryption key of the second wireless device after the FTM request is decoded and complete generating the symmetric key from the private encryption key of the first wireless device and the public encryption key of the second wireless device before encrypting t1and t4.

In Example 23, the subject matter of Example 22 optionally includes where the processing circuitry is configured to generate the symmetric key using an Elliptic Curve Diffie-Hellman or a public key crypto-system method.

In Example 24, the subject matter of any one or more of Examples 22-23 optionally include where the processing circuitry is configured to generate the symmetric key in a parallel process.

In Example 25, the subject matter of any one or more of Examples 20-24 optionally include transceiver circuitry coupled to the processing circuitry; and, one or more antennas coupled to the transceiver circuitry.

Example 26 is an apparatus of a wireless device including: means for encoding a fine time measurement (FTM) request including a public encryption key of the wireless device for transmission to a responder; means for decoding a FTM response from the responder, the FTM response including a public encryption key of the responder, where the FTM response is received at the wireless device at a time t2; means for generating a symmetric key from a private encryption key of the wireless device and the public encryption key of the responder; means for configuring the wireless device to transmit an acknowledgement to the FTM response, where the acknowledgement is to be transmitted at a time t3; means for decoding an encrypted FTM frame from the responder; means for decrypting a media access control (MAC) portion of the encrypted FTM frame with the symmetric key, the decrypted FTM message including a time t1when the FTM response was transmitted and a time t4when the acknowledgement to the FTM response was received; and means for determining a distance of the wireless device from the responder based on time t1, time t2, time t3, and time t4.

In Example 27, the subject matter of Example 26 optionally includes means for generating the public encryption key of the wireless device and the private encryption key.

In Example 28, the subject matter of any one or more of Examples 26-27 optionally include means for beginning generating the symmetric key from the private encryption key of the wireless device and the public encryption key of the responder after time t2and complete generating the symmetric key from the private encryption key of the wireless device and the public encryption key of the responder after the time t3.

In Example 29, the subject matter of Example 28 optionally includes means for generating the symmetric key using an Elliptic Curve Diffie-Hellman method or a public key crypto-system.

In Example 30, the subject matter of any one or more of Examples 28-29 optionally include means for generating the symmetric key in a parallel process.

In Example 31, the subject matter of any one or more of Examples 26-30 optionally include means for configuring the wireless device to transmit an acknowledgement of the encrypted FTM message.

In Example 32, the subject matter of any one or more of Examples 26-31 optionally include means for performing a second FTM measurement with the responder using the symmetric key.

In Example 33, the subject matter of any one or more of Examples 26-32 optionally include means for configuring the wireless device to transmit the FTM request to the responder in accordance with one or both of orthogonal frequency division multiple-access (OFDMA) and multiple-user multiple-input and multiple-output (MU-MIMO).

In Example 34, the subject matter of any one or more of Examples 26-33 optionally include means for decoding the FTM response from the responder, where the public key of the responder is a part of a subelement, the subelement including an subelement identification, a length, and the public key, where the subelement identification identifies the subelement as a public key subelement.

In Example 35, the subject matter of any one or more of Examples 26-34 optionally include means for encoding the FTM request including a subelement, the subelement including a subelement identification, a length, and the public key of the wireless device, where the subelement identification identifies the subelement as a public key subelement.

In Example 36, the subject matter of any one or more of Examples 26-35 optionally include means for decoding the encrypted FTM frame from the responder, where a protected frame bit of a frame control field indicates the MAC portion of the encrypted FTM frame is encrypted.

In Example 37, the subject matter of any one or more of Examples 26-36 optionally include where the wireless device and the one or more stations are each one from the following group: an Institute of Electrical and Electronic Engineers (IEEE) 802.11ax access point, an IEEE 802.11ax station, an IEEE 802.11mc station, an IEEE 802.11mc access point, an IEEE 802.11 station, and an IEEE 802.11 access point.

In Example 38, the subject matter of any one or more of Examples 26-37 optionally include means for processing radio waves.

In Example 39, the subject matter of Example 38 optionally includes means for transmitting and receiving radio waves.

Example 40 is a non-transitory computer-readable storage medium that stores instructions for execution by one or more processors, the instructions to configure the one or more processors to cause an apparatus of a wireless device to: decode a fine time measurement (FTM) request including a public encryption key of a second wireless device; generate a symmetric key from a private encryption key of the first wireless device and the public encryption key of the second wireless device; encode a FTM response to the second wireless device, the FTM response including a public encryption key of the first wireless device; configure the wireless device to transmit the FTM response to the second wireless device at a time t1; decode an acknowledgement from the second wireless device of the FTM response, the acknowledgment to be received at a time t4; encrypt t1and t4with the symmetric encryption key; encode an encrypted FTM with encrypted t1and t4; and configure the first wireless device to transmit the encrypted FTM to the second wireless device.

In Example 41, the subject matter of Example 40 optionally includes the instructions to further configure the one or more processors to cause the apparatus to: generate the public encryption key of the first wireless device and the private encryption key of the first wireless device.

In Example 42, the subject matter of any one or more of Examples 40-41 optionally include the instructions to further configure the one or more processors to cause the apparatus to: begin generating the symmetric key from the private encryption key of the first wireless device and the public encryption key of the second wireless device after the FTM request is decoded and complete generating the symmetric key from the private encryption key of the first wireless device and the public encryption key of the second wireless device before encrypting t1and t4.

In Example 43, the subject matter of any one or more of Examples 40-42 optionally include the instructions to further configure the one or more processors to cause the apparatus to: generate the symmetric key using an Elliptic Curve Diffie-Hellman or a public key crypto-system method.

In Example 44, the subject matter of any one or more of Examples 40-43 optionally include the instructions to further configure the one or more processors to cause the apparatus to: generate the symmetric key in a parallel process.

Example 45 is a method of an apparatus of a wireless device to, the method including: decoding a fine time measurement (FTM) request including a public encryption key of a second wireless device; generating a symmetric key from a private encryption key of the first wireless device and the public encryption key of the second wireless device; encoding a FTM response to the second wireless device, the FTM response including a public encryption key of the first wireless device; configuring the wireless device to transmit the FTM response to the second wireless device at a time t1; decoding an acknowledgement from the second wireless device of the FTM response, the acknowledgment to be received at a time t4; encrypting t1and t4with the symmetric encryption key; encoding an encrypted FTM with encrypted t1and t4; and configuring the first wireless device to transmit the encrypted FTM to the second wireless device.

In Example 46, the subject matter of Example 45 optionally includes the method further including: generating the public encryption key of the first wireless device and the private encryption key of the first wireless device.

In Example 47, the subject matter of any one or more of Examples 45-46 optionally include the method further including: beginning generating the symmetric key from the private encryption key of the first wireless device and the public encryption key of the second wireless device after the FTM request is decoded and complete generating the symmetric key from the private encryption key of the first wireless device and the public encryption key of the second wireless device before encrypting t1and t4.

In Example 48, the subject matter of any one or more of Examples 45-47 optionally include the method further including: generating the symmetric key using an Elliptic Curve Diffie-Hellman or a public key crypto-system method.

In Example 49, the subject matter of any one or more of Examples 45-48 optionally include the method further including: generating the symmetric key in a parallel process.

Example 50 is an apparatus of a wireless device to, the apparatus including: means for decoding a fine time measurement (FTM) request including a public encryption key of a second wireless device; means for generating a symmetric key from a private encryption key of the first wireless device and the public encryption key of the second wireless device; means for encoding a FTM response to the second wireless device, the FTM response including a public encryption key of the first wireless device; means for configuring the wireless device to transmit the FTM response to the second wireless device at a time t1; means for decoding an acknowledgement from the second wireless device of the FTM response, the acknowledgment to be received at a time t4; means for encrypting t1and t4with the symmetric encryption key; means for encoding an encrypted FTM with encrypted t1and t4: and means for configuring the first wireless device to transmit the encrypted FTM to the second wireless device.

In Example 51, the subject matter of Example 50 optionally includes the apparatus further including: means for generating the public encryption key of the first wireless device and the private encryption key of the first wireless device.

In Example 52, the subject matter of any one or more of Examples 50-51 optionally include the apparatus further including: means for beginning generating the symmetric key from the private encryption key of the first wireless device and the public encryption key of the second wireless device after the FTM request is decoded and complete generating the symmetric key from the private encryption key of the first wireless device and the public encryption key of the second wireless device before encrypting t1and t4.

In Example 53, the subject matter of any one or more of Examples 50-52 optionally include the apparatus further including: means for generating the symmetric key using an Elliptic Curve Diffie-Hellman or a public key crypto-system method.

In Example 54, the subject matter of any one or more of Examples 50-53 optionally include the apparatus further including: means for generating the symmetric key in a parallel process.