Contention-based discovery and secure ranging techniques for congested environments

Abstract

A mobile device may receive a plurality of polling messages, each polling message including an identifier of a particular access device that sends the polling message. Each polling message of the plurality of polling messages may be transmitted during a polling phase. The mobile device may select a time slot for a response phase of the communication session. The mobile device may send a response message during the time slot of the response phase. The mobile device may receive an assignment message during the third phase, the assignment message including an assignment slot for a response phase of the future session. The mobile device may perform secure ranging with one or more access devices of the plurality of access devices during the future session using the assigned time slot. The mobile device may provide access credentials to the one or more access devices based on a location determined using the secure ranging.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 363,705, entitled “Contention-Based Discovery And Secure Ranging Techniques For Congested Environments,” filed on April 27, 2022, and U.S. Patent Application No. 17 / 931,072, entitled “Contention-Based Discovery And Secure Ranging Techniques For Congested Environments,” the disclosures of which are incorporated by reference in their entirety and for all purposes. Technical Field

[0003] The present disclosure generally relates to techniques for ranging and access control using communication devices. Background Art

[0004] Access control is the problem of managing access to restricted areas. By validating credentials at the entryway, authorized persons can be granted access to restricted areas. In general, validating credentials for a group of people can be a time-consuming process due to the scale involved. For example, the Tokyo Metro subway system has 8,700,000 passengers per day.

[0005] To be practical, credential verification methods should balance efficiency and security. Physical credentials, such as magnetic stripe cards or near field communication (NFC) cards, can be secure and private. However, physical credentials are inefficient. Users may misplace their credentials, slowing down entryways, and presenting credentials can be time-consuming compared to other methods.

[0006] Contactless authentication such as facial recognition or wireless communications presents privacy and reliability issues. Privacy concerns may cause authorized users to resist the use of facial recognition, and these issues may be significant if a government agency (e.g., a transportation authority) is performing access control. Wireless messages from mobile devices (e.g., a watch or phone) can be used, but such messages may collide in crowded environments, and establishing a secure channel in a one-to-many scenario may be challenging. In addition, body attenuation or interference caused by wireless messages passing through the human body (e.g., if the electronic device is in a back pocket or purse) may become a significant issue in crowded environments. Therefore, there is a need for improved wireless access control. Summary of the invention

[0007] Certain embodiments relate to technology (eg, a device, method, memory, or non-transitory computer-readable medium storing code or instructions executable by one or more processors) for access control technology.

[0008] A general aspect may include a method for communicating with an access device. The method may include receiving a plurality of polling messages. Each polling message may include an identifier of a particular access device that sent the polling message during a polling phase. The method may include selecting a time slot for a response phase of a communication session. The method may include sending a response message during a time slot in the response phase. The method may include receiving an assignment message including an assigned time slot for a response phase of a future session. The assignment message may be received during a third phase. The method may include performing secure ranging with the access device during a future session using the assigned time slot. The method may include providing access credentials to the access device based on a location determined using secure ranging. Other embodiments of this aspect may include corresponding computer systems, apparatus, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the method.

[0009] Specific implementations may include one or more of the following features. The method may include: contention-based discovery of mobile devices, whereby each mobile device may receive multiple polling messages from multiple access devices (e.g., gates); each mobile device may transmit a response message within a randomly selected time slot; the time slot may be further divided into mini-slots, so that on each mini-slot of the time slot, a different access device may listen for a response from the mobile device; each mobile device may direct its response message to a specific access device by transmitting its response in an appropriate mini-slot within the time slot. The response message may include a public key of the mobile device. A secure channel may be established between the mobile device and the access device using their corresponding public keys. A third message from each access device may broadcast a time slot assignment for use by each mobile device during the secure ranging portion of the protocol. Specific implementations of the described technology may include hardware, methods or processes, or computer software on a computer-accessible medium.

[0010] A general aspect includes a method for secure ranging. The method may include receiving a scheduling message from a plurality of access devices. The scheduling message may identify an assigned response time slot for a future ranging session. The method may include receiving a polling message from a plurality of access devices. The polling message may include access device identification information. The method may include determining a reception time (or a transmission time) of a scheduling message for an access device. The method may include sending a response message during an assigned response time slot. The response message includes a mobile device identifier and one or more reception times of the scheduling message. The method may include receiving an access message from an access device. The access message may include a distance between a mobile device and a first access device. The method may include providing an access certificate to the first access device based on the information indicating the distance. Other embodiments of this aspect include corresponding computer systems, apparatuses, and computer programs recorded on one or more computer storage devices, each configured to perform the actions of the method.

[0011] Specific implementations may include one or more of the following features. A method of encrypting a response message with an access device public key. The method may include decrypting the access message using a private key of the mobile device. The information indicating the distance may include the distance as determined by the first access device. Specific implementations of the described technology may include hardware, methods or processes, or computer software on a computer-accessible medium.

[0012] The nature and advantages of embodiments of the present invention may be better understood by referring to the following detailed description and accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 A sequence diagram for performing ranging measurements between an access device and a mobile device according to an embodiment of the present disclosure is shown.

[0014] Figure 2 A sequence diagram of ranging operations involving an access device having three antennas according to an embodiment of the present disclosure is shown.

[0015] Figure 3 An example of a many-to-many ranging scenario involving multiple devices is schematically illustrated.

[0016] Figure 4 A simplified diagram of access control in a congested environment is shown, according to an embodiment.

[0017] Figure 5 is a simplified diagram illustrating competition-based discovery according to an embodiment.

[0018] Figure 6 A simplified diagram of a serialized ranging block is shown according to an embodiment.

[0019] Figure 7A simplified diagram 700 of a ranging block with mini-slots is shown, according to an embodiment.

[0020] Figure 8 is a simplified diagram illustrating safe ranging according to an embodiment.

[0021] Fig. 9 A simplified diagram showing device positioning using secure ranging, according to an embodiment.

[0022] Fig.10 A simplified diagram showing a mobile device being discovered by an access device according to an embodiment.

[0023] Fig.11 A simplified diagram of a mobile device securely ranging from an access device is shown according to an embodiment.

[0024] Fig.12 is a simplified diagram of safe ranging for a mobile device in an entryway, according to an embodiment.

[0025] Fig.13 is a flow chart illustrating a method for performing contention-based ranging with a mobile device.

[0026] Fig.14 is a flow chart illustrating a method for performing safe ranging with a mobile device.

[0027] Fig.15 is a block diagram of components of a mobile device operable to perform ranging according to an embodiment of the present disclosure.

[0028] Fig.16 is a block diagram of an example device according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] Certain embodiments relate to techniques (eg, devices, methods, memories, or non-transitory computer-readable media storing codes or instructions executable by one or more processors) for discovery or ranging techniques.

[0030] Many-to-many secure ranging techniques can be used to perform wireless access control in congested environments. During a contention-based discovery process, a mobile device can be discovered by several access devices (e.g., gates) and assigned time slots for performing future rounds of secure ranging. Keys for secure ranging can also be established during the discovery phase.

[0031] There may be three phases of discovery. The first (polling) phase involves sending a polling message from an access device. The polling message of an access device may include a public key of the access device. The public key may serve as an identifier of the access device, or the polling message may include a separate identifier. Such a public key may be used for encryption during secure ranging.

[0032] The mobile device may respond during a response phase, which may be subdivided into time slots (e.g., access slots), each of which may potentially be further divided into portions of a time slot, referred to as a minislot. The mobile device may select a time slot at random. As long as the number of time slots is large enough, the probability of a collision is low. As another mechanism to avoid collisions, the time slots may be further divided or organized so that each time slot has minislots, each of which is designated for a specific access device. The mobile device may select a specific minislot assigned to the access device whose polling message has the highest signal strength. The response message may include the public key of the mobile device.

[0033] For example, when each access device is scheduled to send a message (such as a polling message) or is scheduled to receive a message (such as an assigned small time slot), the schedule of the polling message may be known. The scheduling information may include a schedule for three phases (e.g., start and stop times), the timing of the polling signal, the time slots including the small time slots assigned to a specific access device, and the timing of other messages during any phase. Such a schedule may be obtained before the discovery phase, such as from a separate beacon device or downloaded from a server. The selection of a specific small time slot may be performed based on proximity measurements (such as signal strength or flight time). In one example, the time difference of arrival (TDoA) from the scheduled transmission time of the polling signal may be used to determine which access device is closest. The response message may be transmitted to the specific access device that is closest or has the strongest signal.

[0034] When used, various criteria may be used to select mini-slots, for example, proximity or in addition to proximity, or at least one or more criteria that do not correspond to proximity. For example, the highest signal strength may not correspond to the nearest access device. For example, the nearest access device may be in front of a person. However, if a mobile device such as a cellular phone is in a person's back pocket, communication with the nearest device may not be effective. The mobile device may be pointed away from the nearest access device, and another access device may therefore be selected. Signal attenuation (e.g., body attenuation) caused by a message passing through a person's body or a person's body in a crowded environment may mean that a response message is transmitted to a specific access device with the strongest signal strength.

[0035] During the third (possibly final) phase, the access device assigns a time slot to a specific mobile device for performing secure ranging and provides the assignment to the mobile device in an assignment message. The assignment message may include a device identifier indicating whether the message is for a specific mobile device or for multiple mobile devices. In practice, a mobile device may be assigned a specific time slot for performing secure ranging with one or more access devices. A mobile device may be assigned one or more time slots for secure ranging. For example, a mobile device may be assigned a first time slot for performing secure ranging with one or more access devices, and may be assigned a second time slot for performing secure ranging with one or more additional access devices.

[0036] During the safety ranging, the assigned access device can listen to messages from the mobile device during the assigned time slot, and the mobile device can communicate with the available access devices. The assignment message can also specify which access device(s) the mobile device should perform safety ranging with. This target subset of one or more access devices may include access devices selected by the mobile device (e.g., based on the message strength of the corresponding polling message) and based on the message (e.g., signal) strength of the response message as determined by the access device. In this way, additional access devices can be identified for safety ranging. Alternatively, both access devices on either side of the selected target access device can be automatically used for safety ranging. The assignment message can be transmitted by the access device that receives the response.

[0037] The necessary keys to establish secure ranging (e.g., the public key of the access device) may be transmitted in the third phase, or may be exchanged during the time slot assigned for the ranging session. If the latter, the first ranging session may only include the exchange of keys. As another example, Bluetooth may be used to transmit any of the keys.

[0038] Once the keys have been exchanged, secure ranging can be used to locate the mobile device. During secure ranging, the access device can listen to messages from the mobile device during the assigned time slot, and the mobile device can communicate with the available access device. Range finding messages (which can be encrypted) are exchanged between the mobile device and multiple access devices. As in contention-based discovery, ranging can be performed in three stages. The polling message can be the same as the polling message used for the discovery phase. In some embodiments, the last stage during contention-based discovery can be used as the polling phase for secure ranging. In response, the mobile device can send a ranging message in the assigned time slot.

[0039] Contention-based discovery and safety ranging may be performed sequentially. For example, a single access device may repeat the ranging / discovery cycle every 333 milliseconds (ms) during 3 Hz (Hz) ranging. The 33 ms segment may be dedicated to time synchronization with the beacon. A 150 ms segment may be used for contention-based discovery, and a separate 150 ms segment may be used for safety ranging. The ranging / discovery cycle may be synchronized by one or more access devices (e.g., all access devices perform safety ranging at the same time), or multiple access devices may perform the cycle at staggered intervals (e.g., one access device performs ranging while another access device performs discovery).

[0040] The response message may be a single message transmitted in the assigned time slot and may be received by any of the access devices; the response message may include the response time required for ranging (i.e., the difference between the sending time of the response message and the receiving time of the polling message). Alternatively, the mobile device may transmit the response times associated with multiple access devices in a single response message.

[0041] One or more access devices (gates) can receive the response ranging message, allowing the distance of the mobile device to multiple reference points to be potentially calculated from one response message. In addition, a passive device (also known as a receiving (RX) access device or a passive receiver) can be installed at or near the access device to receive the response message from the assigned mobile device, and the arrival time difference (TDoA) between the passive devices can be used to calculate the location (e.g., 2D or 3D location) on the mobile device. The message from the access device can provide information to the mobile device, for example, to trigger the transmission of a certificate when the distance is short enough. Alternatively, the final message may include a trigger to transmit the certificate. Once it is determined that the mobile device is in the entrance channel of a specific access device, the mobile device can send the certificate to the specific access device, which can verify the certificate and grant access.

[0042] One aspect of the above process is to assign each of the plurality of mobile devices to a specific time slot for secure ranging by a group of access devices. Since the access devices all agree to assign a given time slot to a specific mobile device, secure ranging can be performed between the plurality of access devices and the plurality of mobile devices in a more efficient manner.

[0043] I. Distance measurement

[0044] In some embodiments, a mobile device or access device may include circuits for performing ranging measurements. Such circuits may include one or more dedicated antennas (e.g., 3) and circuits for processing measured messages. The flight time of a pulse between two mobile devices may be used to perform ranging measurements. In some implementations, the round trip time (RTT) is used to determine, for example, distance information for each antenna. In other implementations, a single trip time in one direction may be used. Ultra-wideband (UWB) radio technology may be used to form pulses.

[0045] A. Sequence diagram

[0046] Figure 1 A sequence diagram for performing ranging measurements between an access device and a mobile device according to an embodiment of the present disclosure is shown. The access device may be part of an infrastructure for controlling access to a restricted area. The mobile device may be a smartphone, a smartwatch, a tablet, etc. Although Figure 1 A single measurement is shown, but the process may be repeated to perform multiple measurements over a time interval as part of a ranging session, where such measurements may be averaged or otherwise analyzed to provide, for example, a single distance value for each antenna. Figure 1 The message sequence of a unilateral two-way ranging protocol is illustrated. The technology proposed in this application is also applicable to other ranging protocols, such as bilateral two-way ranging.

[0047] The access device 110 may initiate a ranging measurement (operation) by sending a ranging request 101 to a mobile device 120 (e.g., a smart phone, a smart watch). The ranging request 101 may include a first set of one or more pulses. The ranging measurement may be performed using a ranging wireless protocol (e.g., ultra-wideband (UWB)). The ranging measurement may be triggered in various ways, for example, based on user input and / or authentication using another wireless protocol (e.g., Bluetooth Low Energy (BLE)). In one example, ranging may begin when certain information in an announcement signal is received from a beacon device.

[0048] At T1, the access device 110 sends a ranging request 101. At T2, the mobile device 120 receives the ranging request 101. T2 may be the average reception time when the plurality of pulses are in the first group. The mobile device 120 may anticipate the ranging request 101 within the time window based on previous communications (e.g., using another wireless protocol). The ranging wireless protocol and the another wireless protocol may be synchronized so that the mobile device 120 may turn on one or more ranging antennas and associated circuits within a specified time window, rather than having them turned on throughout the ranging session.

[0049] In response to receiving the ranging request 101, the mobile device 120 may send a ranging response 102. As shown, the ranging response 102 is sent at time T3 (e.g., the transmission time of a pulse or the average transmission time of a group of pulses). T2 and T3 may also be a group of times of corresponding pulses. The ranging response 102 may include the times T2 and T3 so that the access device 110 can calculate the distance information. Alternatively, an increment between two times (e.g., T3-T2) may be transmitted. The increment may be referred to as a reply time.

[0050] At T4, access device 110 may receive ranging response 102. As with the other times, T4 may be a single time value or a set of time values.

[0051] At 103, the access device 110 calculates distance information 130, which may have various units, such as distance units (e.g., meters) or time (e.g., milliseconds). The time may be equivalent to the distance with a scale factor corresponding to the speed of light. In some embodiments, the distance may be calculated from the total round trip time, which may be equal to T2-T1+T4-T3. More complex calculations may also be used, for example, when the time corresponds to a time group of pulse groups and when frequency correction is implemented.

[0052] B. Triangulation

[0053] In some embodiments, the mobile device may have multiple antennas, for example, to perform triangulation. Individual measurements from different antennas may be used to determine a two-dimensional (2D) position, rather than a single distance value that may be generated by any position on a circle / sphere around the mobile device. A 2D position may be specified using various coordinates, such as Cartesian or polar coordinates, where polar coordinates may include both angular and radial values.

[0054] Figure 2 A sequence diagram of ranging operations involving an access device 210 having three antennas 211-213 according to an embodiment of the present disclosure is shown. The antennas 211-213 may be arranged to have different orientations, for example, to define a field of view for performing ranging measurements. Figure 2 The message sequence of a unilateral two-way ranging protocol is illustrated. The technology proposed in this application is also applicable to other ranging protocols, such as bilateral two-way ranging.

[0055] exist Figure 2 In this example, antenna 211 transmits a packet (comprising one or more pulses) which is received by mobile device 220. The packet may be part of ranging request 201.

[0056] In some embodiments, the access device 210 itself may have multiple antennas. In such implementations, the antennas of the access device 210 may transmit packets to a specific antenna of the mobile device 220 (rather than broadcasting), and the specific antenna may respond to the specific packet. The mobile device 220 may listen at a designated antenna so that both devices know which antennas are involved, or the packet may indicate which antenna the message is for. For example, a first antenna may respond to the received packet; and once a response is received, another packet may be transmitted to a different antenna. This alternative process takes more time and power.

[0057] The packet of ranging request 201 is received at time T2. In some cases, antennas (e.g., ultra-wideband (UWB) antennas) of mobile device 220 can listen substantially simultaneously and respond independently. Mobile device 220 provides ranging response 202 transmitted at time T3. Access device 210 can receive ranging response at one or more of antennas 211, 212, 213. Access device 210 receives ranging response at times T4, T5, and T6, respectively.

[0058] At 203, the processor 214 of the access device 210 calculates the distance information 230, for example, as described herein. The processor 214 may receive the time from the antenna and more specifically from a circuit (e.g., a UWB circuit) that analyzes the messages from the antennas 211-213. As described later, the processor 214 may be an always-on processor that uses less power than an application processor that may perform more general functions. The distance information 230 may be used to determine a 2D or 3D position of the mobile device 220, where such a position may be used to configure a display screen of the mobile device 220. For example, the position may be used to determine the position of the mobile device 220 in a congested environment, such as relative to one or more access devices (e.g., the access device 210), the position of the mobile device in a line, relative to an entryway, in a 2D grid, the position of the mobile device 220 in a 1D, 2D, or 3D distance / position range.

[0059] In some embodiments, to determine which ranging response is from which antenna, the mobile device 220 can inform the access device 210 of the order of response messages to be transmitted, for example during the ranging setup handshake, which can occur using another wireless protocol. In other embodiments, the ranging response can include an identifier that indicates which antenna transmitted the message. These identifiers can be negotiated in the ranging setup handshake.

[0060] The messages in ranging request 201 and ranging response 202 may include very little data in the payload, for example, by including very few pulses. Using very few pulses may be advantageous. The environment of a mobile device (perhaps in a pocket) may make measurement difficult. In some cases, a larger payload is expected, such as a payload containing the response times of multiple access devices. As another example, the antenna of one device may face a different direction from the direction in which other devices are approaching. Therefore, it is desirable to use higher power for each pulse, but there are government restrictions (and battery issues) on how much power can be used within a specified time window (e.g., averaged over 1 millisecond). The length of the packet frame (e.g., ranging frame) containing these messages may be approximately 130 microseconds to 310 microseconds.

[0061] C. Ultra-Wideband (UWB)

[0062] The wireless protocol used for ranging can have narrower pulses (e.g., narrower full width at half maximum (FWHM)) than the first wireless protocol (e.g., Bluetooth) used for initial authentication or communication of ranging setup. In some implementations, the ranging wireless protocol (e.g., UWB) can provide a distance accuracy of 5 cm or better. In various embodiments, the frequency range can be between 3.1 gigahertz (GHz) and 10.6 gigahertz (GHz). Multiple channels can be used, for example, one channel at 6.5 GHz and another channel at 8 GHz. Therefore, in some cases, the ranging wireless protocol does not overlap with the frequency range of the first wireless protocol (e.g., 2.4 GHz to 2.485 GHz).

[0063] The ranging wireless protocol may be specified by IEEE 802.15.4, which is a type of UWB. Each pulse in a pulse-based UWB system may occupy the entire UWB bandwidth (e.g., 500 megahertz (MHz)), allowing the pulse to be localized in time (i.e., a narrow width in time, e.g., 0.5 nanoseconds to a few nanoseconds). In terms of distance, for a 500MHz wide pulse, the pulse may be less than 60cm wide, and for a 1.3GHz bandwidth pulse, the pulse may be less than 23cm. Because the bandwidth is so wide and the width in real space is very narrow, very accurate time-of-flight measurements can be obtained.

[0064] Each of the ranging messages (also referred to as frames or packets) may include a pulse sequence that may represent modulated information. Each data symbol in a frame may be a sequence. A packet may have a preamble that includes, for example, header information of a physical layer and a MAC layer, and may include a destination address. In some implementations, a packet frame may include a synchronization portion and a start frame delimiter that may be timed to line up.

[0065] The packet may include information on how to configure security and include encryption, for example, an identifier of which antenna transmits the packet. The encrypted information may be used for additional authentication. However, for ranging operations, it may not be necessary to determine the content of the data. In some embodiments, the timestamp of the pulse of a particular data slice can be used to track the difference between sending and receiving. The content (e.g., the decrypted content) can be used to match the pulses so that the correct time difference can be calculated. In some specific implementations, the encrypted information may include an indicator of which phase the authentication message corresponds to, for example, ranging request 201 may correspond to phase 1, and ranging response 202 may correspond to phase 2. Such use of indicators may be helpful when more than two devices perform ranging operations near each other.

[0066] Narrow pulses (e.g., about one nanosecond wide) can be used to accurately determine distance. High bandwidth (e.g., a 500 MHz spectrum) allows narrow pulses and accurate position determination. Cross-correlation of pulses can provide timing accuracy that is a fraction of the pulse width, for example, providing accuracy within hundreds or tens of picoseconds, which provides sub-meter ranging accuracy. The pulses can represent ranging waveforms that add 1 and subtract 1 in a certain pattern that is recognized by the receiver. Distance measurement can use round-trip time measurement, also known as time of flight measurement. As described above, an access device or a mobile device can transmit a set of timestamps, which can eliminate the necessity for clock synchronization between the two devices.

[0067] II. Many-to-many scenario

[0068] For some applications, multiple access devices may perform ranging with multiple mobile devices. Techniques may be implemented to overcome challenges due to mobile device or access device clock drift. These techniques may minimize overlapping communications that may occur due to clock drift or other synchronization issues.

[0069] Figure 3 A many-to-many communication group involving two access devices (access device 302 and access device 304) and two mobile devices (mobile device 306 and mobile device 308) is illustrated. Figure 3 Four devices are depicted in FIG, but these techniques can be used in many devices. Figure 3 is an exemplary depiction of many-to-many ranging that can be improved.

[0070] Many-to-many ranging can present challenges. For example, signal collision or co-channel interference can be caused by multiple devices transmitting on the same frequency at the same time. At the same time, overlap between signals can cause interference, making the signal difficult to understand. Interference can be caused by transmissions on separate frequency bands known as adjacent channel interference or crosstalk. If the signal is not adequately filtered, the signal can transmit power into an adjacent channel (e.g., frequency band). In addition, multipath propagation, or signals arriving at the antenna through different paths, can cause signal interference.

[0071] Various embodiments can solve such problems using a published schedule about when certain messages are transmitted (e.g., phases, time slots, mini-slots, etc.). In addition, the scheduling discovery process (phase) can determine how to assign time slots. Information about the assignment can be provided from the access device to the mobile device.

[0072] Any of the access devices 302 and 304 can be designated as a coordinator for a ranging session with one of the mobile devices 306 or 308. A particular access device can provide an assignment message (e.g., including an assignment time slot) to a particular mobile device, and thus the particular access device can be considered a coordinator for a ranging session with the particular mobile device. For example, the access device 302 can be a coordinator for the mobile device 306, and the access device 304 can be a coordinator for the mobile device 308. A coordinator can be an access device whose mini-slot is selected by a mobile device, for example, based on signal strength or other criteria. In some cases, a coordinator can assign mini-slots to mobile devices based on signal strength or other criteria.

[0073] As an example, an access device can be an entrance gate at a transfer station or an entrance to a company campus, where employees with badges can enter access control areas. Mobile devices can be smart phones, tablets, or other mobile electronic devices. Mobile devices can be devices from any number of different manufacturers, types, or models. Each mobile device may include a unique identification number. In some embodiments, the unique identification number can be a universal unique identifier (UUID). UUID can be a 128-bit number for identifying a computing device such as an access device or mobile device. UUID can be randomly generated by the manufacturer and assigned individually to the mobile device hardware.

[0074] III. Access Control in Congested Environments

[0075] Access control to restricted areas can be achieved in part by locating mobile devices. However, access control in congested environments can present technical challenges. Message collisions, body attenuation, or pathfinding errors can mean that ranging is inaccurate or sometimes not possible. In order to perform access control in congested environments, a contention-based discovery process can be used to establish a secure connection between a mobile device and one or more access devices. Ranging performed via a secure channel can be used to locate the mobile device, and an access decision can be determined when the device reaches an entryway to a restricted area or when the mobile device is within a threshold distance of an access device.

[0076] Figure 4 A simplified diagram of access control in a congested environment 400 according to an embodiment is shown. The congested environment 400 can be any environment where access control is performed for a large number of people. For example, the congested environment 400 can be a theme park, a corporate campus, a university campus, a government facility, a stadium, a music venue, a hospital, a public transportation entrance, etc.

[0077] In this example, congested environment 400 is a ten-meter by five-meter space, where people (e.g., person 405) are approximately one meter apart. Congested environment 400 may be part of unrestricted area 410, and door 415 may perform access control to restrict access to restricted area 420. Doors such as door 415 may include one or more authentication devices and one or more access control devices. For example, an access control device may include an arm, barrier, or alarm that controls access to restricted area 420 (e.g., an alarm may sound if an unauthorized person enters entryway 425).

[0078] If person 405 is within range of gate 415 (e.g., within semicircle 430), a mobile device in the person's possession can communicate with an authentication device in the gate. Before the mobile device is within range, the mobile device can communicate with a beacon device 435a-b (e.g., a transmitting device) that broadcasts an ultra-wideband (UWB) message and possibly a Bluetooth message. The mobile device is capable of receiving timing information (also known as scheduling information) and using the broadcast messages to calculate an approximate location (e.g., via a downlink time difference of arrival (TDoA)). The mobile device can receive a schedule of sessions, phases, time slots, and / or mini-slots from the beacon device. A mini-slot or time slot can be associated with an authentication device identifier such as a universally unique identifier (UUID).

[0079] Within range (e.g., within semicircle 430), the mobile device can perform contention-based discovery to establish communication with one or more access devices. Once communication is established, secure ranging can be used to locate the mobile device and person 405. If person 405 is within entryway 425, the mobile device can provide access credentials to door 415, and the door can grant access based on the access credentials.

[0080] A. Competition-based discovery

[0081] For some applications, a contention-based discovery protocol may allow multiple mobile devices or access devices in a congested environment to communicate over a radio channel without prior coordination. The protocol may include rules defining how and when an access device may send or receive packets, thereby giving multiple access devices a reasonable opportunity to operate. A contention-based discovery protocol may define a polling phase, a response phase, and a final phase.

[0082] 1. Polling phase

[0083] The polling phase in contention-based discovery informs a mobile device that the device is within range of an access device. Messages transmitted by an access device during the polling phase may contain timing information that defines how and when the mobile device may respond to the access device.

[0084] Figure 5 5 is a simplified diagram 500 showing contention-based discovery according to an embodiment. In the polling phase 505, the access device may broadcast polling messages 510a-d. Each access device may broadcast messages (e.g., polling messages 510b) during regular intervals referred to as time slots 515. The polling messages may be ultra-wideband radio transmissions, and each polling message may contain a universally unique identifier (UUID) identifying the access device. Each access device may be assigned a specific time slot, for example, as shown.

[0085] The polling message may be received by a mobile device. The polling message 510a-d may include timing information including a broadcast time and / or scheduling information. The polling message may include a public key of an access device. The broadcast time of a single polling message may be the time at which the access device broadcasts the message. The mobile device may use the broadcast message to calculate the approximate distance between the mobile device and the access device using a downlink TDoA technique (e.g., by determining the difference between the reception time and the broadcast time). Clock synchronization may occur via a beacon device that provides a timing signal (synchronized with the access device) by which an offset relative to the clock of the mobile device may be determined. In some implementations, the mobile device may obtain the timing of the infrastructure (i.e., beacons and access devices) by receiving one or more beacon transmissions in the beacon transmission. This time synchronization and scheduling information may allow the mobile device to know when the device should listen for polling messages from one or more access devices. In some implementations, the mobile device may assume the broadcast time based on the scheduling information received from the beacon device. Therefore, the approximate distance may be determined without requiring the polling message to include the broadcast time.

[0086] The scheduling information can be a schedule of time slots or mini-slots that indicate when the access device will listen for response messages. In other examples, the scheduling information can be received from a beacon device or downloaded from the Internet prior to contention-based discovery. The scheduling information can allow the mobile device to respond to a specific access device during the response phase described below. Approximate distance or other characteristics of the polling message (e.g., received message strength indicator (RSSI)) can be used to determine which access device to respond to. For example, the mobile device can use the approximate distance or RSSI to identify the nearest access device and respond to it.

[0087] However, the mobile device may use other methods to determine which access device it should respond to. In addition, the selected access device may not necessarily be the access device that is closest to the mobile device. For example, the mobile device may be placed in a handbag, in which case it may be pointed away from the nearest access device and a different access device may be selected. In addition, signal interference (such as interference caused by body attenuation) may cause the mobile device to select an access device that is not the closest.

[0088] 2. Response phase

[0089] During the response phase, the mobile device may select and respond to an access device during a randomly selected time slot. Each time slot may be subdivided into regular intervals or portions of a time slot called mini-slots, and each mini-slot may be assigned to a specific access device. During the randomly selected time slot, the mobile device may respond to a specific access device by sending a response message during the mini-slot of the specific access device. Although the selection of the time slot may be random, logic may dictate the mini-slot selection.

[0090] return Figure 5 , the response message may be transmitted during the selected time slot, and may be transmitted during the mini-slot corresponding to the access device determined during the polling phase. For example, the mobile device may decide to transmit the response message 520 during the mini-slot 525 corresponding to the access device that sent the polling message 501b. To avoid collisions, the response phase 530 may be divided into one or more time slots 535. The mobile device may randomly select and send a response phase during a time slot. In some cases, the mobile device may include timing information in the response message, such as the sending time of the response message, the reply time, or the public key of the mobile device.

[0091] Randomly selecting time slots and dividing time slots into small slots can reduce the number of collisions in a crowded environment. For example, without small slots, response message 520 and response message 540 will collide. Similarly, without random time slot selection, response message 520 and response message 545 may have collided.

[0092] Mini-slots may also allow shorter ranging blocks than full serialization. Full serialization would correspond to performing all communications to each gate in a serial manner.

[0093] Figure 6 A simplified diagram 600 of a serialized ranging block according to an embodiment is shown. In full serialization, each access device performs ranging in a sequential round during a serialized ranging block 605. Serialization may mean that a first access device performs all three phases of contention-based discovery before a second access device begins the discovery process. A ranging round (e.g., ranging round 610) may include a polling phase 615, a response phase 620, and a final phase 625 for a single access device.

[0094] Figure 7 A simplified diagram 700 of a ranging block or discovery block (session) with mini-slots according to an embodiment is shown. Mini-slots may allow for compression of ranging blocks, wherein mini-slots for each access device are interleaved in a continuous order. During the polling phase 705, multiple access devices may transmit polling messages sequentially. In the response phase 710, the access slot 715 may be subdivided into one or more mini-slots (e.g., mini-slot 720). Mini-slots may be created for one or more of the access devices participating in the polling phase 705. Mini-slots may mean that each access device may receive messages during the access slot 715.

[0095] Small time slots can significantly reduce the length of the ranging block. A ranging block with small time slots can take one-third of the time of the serialized ranging block 605. For example, the access device processing time can be 1 millisecond (ms), and the mobile device processing time can take 2ms. If there are five access devices and twenty time slots, the serialized ranging block 605 can last 120ms ([2ms+1ms*20+2ms]*5=120ms). In contrast, a ranging block with small time slots can take 40ms (2ms*5+1ms*20+2ms*5=40ms).

[0096] 3. Phase 3

[0097] In the third phase, a time slot assignment and potentially a secure connection is established between the mobile device and the access device. The access device may transmit an assignment message to the mobile device as an acknowledgement to the mobile device and coordinate secure ranging.

[0098] return Figure 5, assignment messages 550a-d can be transmitted during the response phase 555. The assignment messages 550a-d can be responses to response messages received during the response phase 530. In the response phase 530, the mobile device can select an access device to respond based on proximity (e.g., calculated distance, RSSI). However, the access device can be the device closest to more than one mobile device. For example, the response message 520 and the response message 545 are transmitted by the mobile device closest to the same access device. In this case, the access device or multiple access devices working in coordination can select between mobile devices based on proximity. However, other selection criteria are also contemplated. Therefore, one or more access devices can use timing information in the response message or the message strength of the response to select a mobile device (e.g., via RSSI or TDoA).

[0099] The assignment message may include scheduling information for secure ranging. The scheduling information may include the number and length of time slots for secure ranging, and which response time slot the mobile device should use during secure ranging. In some cases, a mobile device may be assigned more than one response time slot. The assignment message may also include the public key of one or more access devices and additional verification information. The assignment message may include one or more device identifiers, and may assign one or more dedicated time slots in the secure ranging portion of the exchange to the selected mobile device. The assignment message may include the address of one or more mobile devices and a list of assigned time slots. If the assignment message is too long, it may be segmented and transmitted in multiple assigned time slots. If there are not enough assigned time slots in the third phase, the access device may decide to split the assignment message and transmit it during the next round of contention-based discovery. Timing information for secure ranging scheduling may also be obtained before or after contention-based discovery, and a timing schedule including the length and number of time slots or mini-slots may be downloaded, for example, from a beacon device or a network such as the Internet.

[0100] B.Safe distance measurement

[0101] The secure ranging protocol may allow mobile devices and access devices to exchange messages in a congested many-to-many environment. A response message sent by a mobile device may be received by multiple access devices, and a single potentially protected message may be used to locate the device. When the mobile device is close enough to an access device, access credentials may be exchanged between the devices. Secure ranging may include a polling phase, a response phase, and a final phase.

[0102] 1. Polling phase

[0103] During the polling phase, the access device may send polling packets in consecutive time slots. The polling packets may be broadcast signals that may be received by multiple mobile devices. For example, in addition to or in lieu of transmitting in an assignment message in a discovery session, the access device may send a polling message that identifies the sending access device and may identify a response time slot. The polling message may be protected by a secure channel using public keys exchanged between the access device and the mobile device. For example, a group key may be derived to protect the broadcast signal.

[0104] Figure 8 800 is a simplified diagram showing a safe distance measurement according to an embodiment. The polling phase 805 may allow an access device (e.g., access device 810) to transmit with a reduced risk of collision. For example, access device 810 may send a polling message 815 during time slot 820. The mobile device may know to listen for polling messages during time slot 820 (e.g., based on the assignment of access device 810), and time slot 820 may have been provided to the mobile device via an assignment message, as discussed in Section III.A.3. In some cases, multiple time slots may be assigned to a mobile device. The polling message may identify the access device by using a device identifier such as a universally unique identifier (UUID).

[0105] 2. Response phase

[0106] Ranging between a mobile device and one or more access devices can occur during the response phase. The mobile device can send a single response message (e.g., with timing information for determining distance) that can be received by one or more access devices. The location of the mobile device can be triangulated with a single response message because the message can be received by multiple access devices.

[0107] return Figure 8, a mobile device that receives the polling message 815 may send one or more response messages 825a-d during a designated response time slot 830. In some cases, the response message 825a-d may be a single response message received by multiple access devices. In some cases, for example, if ranging is performed with more than one access device, more than one response time slot 830 may be assigned to the mobile device. As shown, the mobile device performs ranging with all four access devices by sending a single response message that can be received by each access device, but ranging with fewer or more access devices may be performed. The time slot may have been specified in the polling message from Section III.B.1 or the assignment message from Section III.A.3. During the response phase 835, one or more assigned access devices may listen for response messages during each time slot, for example, because an access device may be assigned to perform ranging with a specific mobile device during a specific time slot. The response message 825a-d may include the reply time (e.g., the difference between the polling message reception time and the response message transmission time), and the access device may calculate the distance between the access device and the mobile device (e.g., via TDoA, RSSI, etc.). The calculated distance and the known location of the access device may be used to triangulate the location of the mobile device.

[0108] In some implementations, the individual playback times (or other timing information) for each access device may be included in a single response message, which may effectively be a combination of response messages 825a-d. Each piece of timing information may be tagged for the corresponding access device.

[0109] In another example, the mobile device can respond to more than one access device in different time slots. If the mobile device is assigned multiple time slots, the mobile device can listen for polling messages sent by multiple access devices during the polling phase described in Section III.B.1. The mobile device can calculate the response time of each access device and include the response time in the response message sent during two or more response time slots. Therefore, the response message to multiple access devices can be performed in various ways.

[0110] Fig. 9A simplified diagram of device positioning using secure ranging according to an embodiment is shown. Various techniques can be used for device positioning, including downlink arrival time difference (DL-TDoA), multiple two-way ranging (TWR), uplink arrival time difference (UL-TDoA), etc. Access devices including transmit / receive (TX / RX) access devices 905a-b and receive (RX) access devices 910a-b (also referred to as passive devices or passive receivers) can monitor for response messages 915a-d from mobile devices 920. Response messages 915a-d may include reply times, which include the reception time of the polling message from Part III.B.1 and the transmission time of the response message. Each access device (including TX / RX access devices 905a-b and RX access devices 910a-b) can calculate the linear distance between the access device and the mobile device 920. The distance can be triangulated to locate the mobile device at a specific location.

[0111] 3. Final stage

[0112] During the final phase, the access device may receive an access message from the access device. The access message may provide a location to the mobile device, or provide timing information so that the mobile device can calculate its location, or provide verification and scheduling information for access credential exchange. If the mobile device is close enough to the access device, or is located in an entryway to the restricted area, the mobile device may provide access credentials to the access device. The access credentials may be used by the access device to determine whether the mobile device should be granted access to the restricted area.

[0113] return Figure 8 , an access message 840 may be transmitted during a final phase 845 (e.g., a third phase). The access message 840 may provide information, such as one or more of the following: the location of the mobile device (e.g., the distance between the mobile device and the nearest access device), a trigger message, timing information related to a response time (or other time) from the access device for the mobile device to determine the range, and / or scheduling information for a future round of security ranging or a future round of data transfer, so that the mobile device can provide access credentials to the access device. The mobile device may use the timing information to calculate the location of the mobile device. If the mobile device is within a threshold distance of the access device or the entryway, the access credentials may be provided to the access device. The trigger message may cause the mobile device to provide the access credentials. The threshold distance may be 0.01 meters (m), 0.1m, 1m, 1.5m, 2m, 3m, 4m, 5m, 10m, 100m, etc. If the mobile device is outside the threshold distance, the access message may contain scheduling information, such as an assigned time slot or a response time slot.

[0114] IV. Exemplary Access Control Walkthrough

[0115] In the illustrative example, a person is trying to enter a restricted area. In this case, the restricted area is a public transportation terminal, and the person is trying to enter a subway system.

[0116] Fig.10 A simplified diagram 1000 of a mobile device being discovered by an access device is shown in accordance with an embodiment. A mobile device owned by a person 1005 is discovered by an access device 1010 using contention-based ranging as described in Section III.A.

[0117] Continuing with this example, after the mobile device is discovered, the mobile device securely ranges with the access device. Fig.11 A simplified diagram 1100 of a mobile device safely ranging with an access device according to an embodiment is shown. During safe ranging, a mobile device owned by a person 1105 safely ranges with access devices 1110a-b. In this case, the mobile device is assigned more than one response slot, and the mobile device can safely range with two access devices 1110a-b. The safe ranging can occur as described in Section III.B. Messages 1115a-b exchanged between the mobile device and the access devices 1110a-b can be used to locate the mobile device and the person 1105. These messages may include polling messages, response messages, and access messages.

[0118] Safety ranging may continue until the mobile device is within the entryway of the restricted area. Fig.12 1200 is a simplified diagram of secure ranging for a mobile device in an entryway according to an embodiment. Secure ranging between access devices can be used to locate a mobile device and a person 1205 within an entryway 1210. Once the mobile device is in the entryway 1210, access credentials can be provided to the access device 1220 via a message 1215. The access credentials can be provided via a wireless message (e.g., UWB, Wi-Fi, Bluetooth, etc.). An access control device 1225 (in this case a robotic arm) can allow entry to a restricted area 1230.

[0119] V. Methods for performing many-to-many ranging

[0120] Due to the number of devices involved, the positioning of a mobile device at an access device may require the use of a many-to-many ranging strategy. Contention-based discovery may allow a mobile device to establish a secure connection with a mobile device, and secure ranging may be used to locate the mobile device. Many-to-many ranging may be performed using contention-based discovery, secure ranging, or a combination of both methods.

[0121] A. Competition-based discovery flow chart

[0122] Fig.13is a flow chart illustrating a method 1300 for performing contention-based ranging with a mobile device. In some implementations, Fig.13 One or more method blocks of may be performed by a mobile device (e.g., mobile device 120, mobile device 220, mobile device 306, mobile device 308, mobile device 1500, mobile device 1600). In some specific implementations, Fig.13 One or more method blocks of may be performed by another device or a group of devices separate from or including the mobile device. Additionally or alternatively, Fig.13 One or more method blocks may be performed by one or more components of a mobile device (e.g., mobile device 120, mobile device 220, mobile device 306, mobile device 308, mobile device 1500, mobile device 1600), such as an always-on processor (AOP) 1530, an application processor 1540, a processor 1618, a computer-readable medium 1602, an input / output (I / O) subsystem 1606, an ultra-wideband (UWB) circuit 1515, a BT / WiFi circuit 1525, a wireless circuit 1608, etc.

[0123] At block 1310, a polling message may be received. Each polling message (e.g., polling messages 510a-d) may include an identifier for a particular access device. The unique identifier may be a universally unique identifier (UUID). Each of the plurality of polling messages may be sent during a polling phase. The polling message may be sent by an access device (e.g., access device 110, access device 210, access device 302, access device 304). The polling message may be received during a polling phase (e.g., polling phase 505, polling phase 705).

[0124] At block 1320, the mobile device may select a time slot. The selected time slot may be a time slot in a response phase that includes one or more mini-slots (e.g., a portion of a time slot) (e.g., time slot 535, time slot 715), and in some cases, the selected time slot may be a mini-slot (e.g., mini-slot 525, mini-slot 720). The mobile device may select a mini-slot based on the proximity between the mobile device and the access device. The selected mobile device may be selected using the arrival time or received message strength (RSS) of one or more polling messages from block 1310. Thus, a time slot may include a plurality of portions, wherein each portion of the time slot corresponds to a respective access device in the plurality of access devices.

[0125] At block 1330, the mobile device may send a response message. The mobile device may send a response message (e.g., response message 520, response message 540, response message 545) during a time slot of a response phase (e.g., response phase 530, response phase 710). The time slot may be a time slot selected from block 1320. The response message may include a device public key of the mobile device. The response message may be sent during a mini-slot, and the mini-slot may be associated with a particular access device.

[0126] At block 1340, the assignment message may be received by the mobile device. The assignment message may be transmitted during a third phase (e.g., a final phase). The assignment message may include an assignment time slot or other timing information for a response phase of a future session. The assignment message may include a public key of the access device. The assignment message may include instructions for the mobile device to perform secure ranging with a specific access device referred to as an assigned access device. The instructions may include a unique identifier that identifies the assigned access device.

[0127] At block 1350, the mobile device may perform secure ranging. Secure ranging may be performed between the mobile device and one or more access devices. Secure ranging may include an exchange of ranging messages between the mobile device and the one or more access devices. The mobile device may use the assigned time slots from block 1340 to perform secure ranging during future sessions. Secure ranging may be performed according to Section III or Fig.14 The method disclosed in is executed.

[0128] Circuitry of one or more access devices or mobile devices may perform various levels of processing of ranging messages, such as to determine timestamps. A mobile device may receive a ranging response message (e.g., ranging response 102) and determine a timestamp for sending one or more ranging request messages (e.g., ranging request 101) and a timestamp for one or more ranging response messages, such as Figure 1 and Figure 2 The mobile device or one or more access devices can use these times to determine the distance between the mobile device and one or more access devices. This ranging can be performed once, a specified number of times, or continuously until a stop ranging request is processed.

[0129] At block 1360, the mobile device may provide access credentials to the access device. The mobile device may provide credentials based on a location determined using secure ranging. For example, if the mobile device is found to be within a threshold distance of an access device or entryway via secure ranging, the mobile device may provide access credentials to the access device. The access credentials may be provided in response to a trigger message received in secure ranging.

[0130] Method 1300 may include additional implementations, such as any single implementation or any combination of implementations described below and / or in combination with one or more other processes described elsewhere herein.

[0131] although Fig.13 An example block diagram of method 1300 is shown, but in some implementations, Fig.13 The method 1300 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted. Additionally or alternatively, two or more of the blocks of the method 1300 may be performed in parallel.

[0132] B. Safe distance measurement flow chart

[0133] Fig.14 is a flow chart illustrating a method 1400 for performing a safe distance measurement with a mobile device. In some implementations, Fig.14 One or more method blocks of may be performed by a mobile device (e.g., mobile device 120, mobile device 220, mobile device 306, mobile device 308, mobile device 1500, mobile device 1600). In some specific implementations, Fig.14 One or more method blocks of may be performed by another device or a group of devices separate from or including the mobile device. Additionally or alternatively, Fig.14 One or more method blocks may be performed by one or more components of a mobile device (e.g., mobile device 120, mobile device 220, mobile device 306, mobile device 308, mobile device 1500, mobile device 1600), such as an always-on processor (AOP) 1530, an application processor 1540, a processor 1618, a computer-readable medium 1602, an input / output (I / O) subsystem 1606, an ultra-wideband (UWB) circuit 1515, a BT / WiFi circuit 1525, a wireless circuit 1608, etc.

[0134] At block 1410, a mobile device may receive an assignment message from one or more access devices. The received assignment message may identify an assigned response time slot (e.g., response time slot 830) for a response phase (e.g., response phase 835) of a future ranging session. The received assignment message may be sent by an access device (e.g., access device 110, access device 210, access device 302, access device 304). The assignment message may be the assignment message received at block 1340. The assignment message may be received from a beacon device (e.g., beacon devices 435a-b).

[0135] At block 1420, the mobile device may receive a polling message (e.g., ranging request message, ranging request 101, polling message 815) from one or more access devices. The polling message may include access device identification information, such as a universally unique identifier (UUID). The polling message may be sent by an access device (e.g., access device 110, access device 210, access device 302, access device 304).

[0136] At block 1430, the mobile device may determine a reception time of the assignment message of one or more access devices. The reception time may be determined using a clock (eg, sensor 1646), and the clock state may be recorded, for example, when the assignment message is received at block 1410.

[0137] At block 1440, the mobile device may send a response message during the assigned response time slot. The response message (e.g., ranging response message, ranging response 102, response message 825a-d) may include a mobile device identifier (e.g., UUID) and timing information. As an example, the timing information may include a response time, which may be the difference between the polling message reception time and the response message transmission time. As another example, the timing information may include a reception time and a transmission time, respectively. In either example, the timing information includes the reception time. The response message may be encrypted with an access device public key. The response message may be sent to one or more passive devices (e.g., receiving (RX) access devices 910a-b).

[0138] At block 1450, the mobile device may receive an access message 840 from a first access device (e.g., access device 810) among a plurality of access devices. The access message may include information indicating the distance between the mobile device and the first access device. The access message may be decrypted using a private key of the mobile device. The information indicating the distance may include a distance as determined by the first access device. As another example, the access message may include a time of receipt of a response message from block 1440 at one or more access devices (e.g., as part of a response time), and the mobile device may determine the distance between the mobile device and the access device. The access device may be a TX / RX access device (e.g., TX / RX access device 905a-b) or an RX access device (RX access device 910a-b).

[0139] At block 1460, the mobile device may provide access credentials to the first access device. The access credentials may be provided in response to an access message. For example, the access message may be a trigger message / command indicating that the mobile device may transmit the access credentials, for example, because the mobile device is close enough. In addition to direct triggering, the access message may indicate that the access credentials should be transmitted by providing information indicating the distance, so that the mobile device may execute decision logic to determine exactly when to transmit the access credentials, for example, by comparing the determined or received distance with a threshold. As an example, the information indicating the distance may be timing information, which may include one or more of the following: a polling message, an assignment message, a response message, or any one or more of the sending time, receiving time, or reply time of the assignment message. The information indicating the distance may include the received signal strength of the polling message, the assignment message, the response message, or the assignment message. The access credentials may be provided in response to a trigger message received via the access message. The access credentials may be provided to one or more passive devices (e.g., receiving (RX) access devices 910a-b).

[0140] Circuitry of one or more access devices or mobile devices may perform various levels of processing of ranging messages, such as to determine timestamps. A mobile device may receive a ranging response message (e.g., ranging response 102) and determine a timestamp for sending one or more ranging request messages (e.g., ranging request 101) and a timestamp for one or more ranging response messages, such as Figure 1 and Figure 2 The mobile device or one or more access devices can use these times to determine the distance between the mobile device and one or more access devices. This ranging can be performed once, a specified number of times, or continuously until a stop ranging request is processed.

[0141] Method 1400 may include additional implementations, such as any single implementation or any combination of implementations described below and / or in combination with one or more other processes described elsewhere herein.

[0142] although Fig.14 An example block diagram of method 1400 is shown, but in some implementations, Fig.14 The method 1400 may include additional blocks, fewer blocks, different blocks, or differently arranged blocks than those depicted. Additionally or alternatively, two or more of the blocks of the method 1400 may be performed in parallel.

[0143] VI. Mobile device for performing ranging

[0144] Fig.151 is a block diagram of components of a mobile device 1500 operable to perform ranging according to an embodiment of the present disclosure. The mobile device 1500 includes antennas for at least two different wireless protocols, as described above. A first wireless protocol (e.g., Bluetooth) can be used to authenticate and exchange ranging settings. A second wireless protocol (e.g., UWB) can be used to perform ranging with another mobile device.

[0145] As shown, mobile device 1500 includes a UWB antenna 1510 for performing ranging. UWB antenna 1510 is connected to UWB circuit 1515 for analyzing detected messages from UWB antenna 1510. In some embodiments, mobile device 1500 includes three or more UWB antennas, for example, for performing triangulation. Different UWB antennas may have different orientations, for example, two antennas are in one direction and the third antenna is in another direction. The orientation of the UWB antenna can define the field of view for ranging. As an example, the field of view can span 120 degrees. Such provisions can allow determination of which direction the user is pointing the device relative to one or more other nearby devices. The field of view may include any one or more of the pitch angle, yaw angle, or roll angle.

[0146] The UWB circuitry 1515 may communicate with an always-on processor (AOP) 1530, which may perform further processing using information from the UWB messages. For example, the AOP 1530 may perform ranging calculations using timing data provided by the UWB circuitry 1515. The AOP 1530 and other circuitry of the device may include dedicated circuitry and / or configurable circuitry, e.g., via firmware or other software.

[0147] As shown, the mobile device 1500 also includes a Bluetooth (BT) / Wi-Fi antenna 1520 for transmitting data with other devices. The BT / Wi-Fi antenna 1520 is connected to a BT / Wi-Fi circuit 1525 for analyzing detected messages from the BT / Wi-Fi antenna 1520. For example, the BT / Wi-Fi circuit 1525 can parse the message to obtain data (e.g., an authentication tag), which can be transmitted to the AOP 1530. In some embodiments, the AOP 1530 can use the authentication tag to perform authentication. Therefore, as part of the authentication process, the AOP 1530 can store or retrieve a list of authentication tags to which the received tags are compared. In some specific implementations, such functions can be implemented by the BT / Wi-Fi circuit 1525.

[0148] In other embodiments, the UWB circuitry 1515 and the BT / Wi-Fi circuitry 1525 may alternatively or additionally be connected to an application processor 1540, which may perform similar functions as the AOP 1530. The application processor 1540 typically requires more power than the AOP 1530, and thus power may be saved by having the AOP 1530 process certain functions so that the application processor 1540 may remain in a sleep state, such as a disconnected state. For example, the application processor 1540 may be used to transmit audio or video using BT / Wi-Fi, and the AOP 1530 may coordinate the transmission of such content and the communication between the UWB circuitry 1515 and the BT / Wi-Fi circuitry 1525. For example, the AOP 1530 may coordinate the timing of UWB messages relative to BT advertisements.

[0149] To perform ranging, the BT / Wi-Fi circuit 1525 may analyze the announcement message from the other device to determine that the other device wants to perform ranging, for example, as part of a process for sharing content. The BT / Wi-Fi circuit 1525 may communicate the notification to the AOP 1530, which may schedule the UWB circuit 1515 to be ready to detect a UWB message from the other device.

[0150] For the device that initiates the distance measurement, its AOP can perform the distance measurement calculation. In addition, the AOP can monitor the change of the distance between another device. For example, AOP 1530 can compare the distance with a threshold and provide an alarm when the distance exceeds the threshold, or potentially provide a reminder when the two devices become close enough. An example of the former may be a situation where a parent expects to be alerted when the child (and most likely the child's device) is too far away. An example of the latter may be a situation where someone expects to be reminded to mention something when talking to the user of another device. Such monitoring performed by the AOP can reduce the power consumption of the application processor.

[0151] VII. Example Equipment

[0152] Fig.161 is a block diagram of an example electronic device 1600. Device 1600 generally includes computer-readable media 1602, a processing system 1604, an input / output (I / O) subsystem 1606, wireless circuitry 1608, and audio circuitry 1610 including a speaker 1612 and a microphone 1614. These components may be coupled via one or more communication buses or signal lines 1603. Device 1600 may be any portable electronic device, including a handheld computer, a tablet computer, a mobile phone, a laptop computer, a tablet device, a media player, a personal digital assistant (PDA), a key fob, a car key, an access card, a multifunction device, a mobile phone, a portable gaming device, a headset, etc., including combinations of two or more of these items.

[0153] Obviously, Fig.16 The architecture shown is only one example of an architecture for device 1600 , and device 1600 may have more or fewer components or components in a different configuration than shown. Fig.16 The various components shown may be implemented in hardware, software, or a combination of both hardware and software, including one or more signal processing circuits and / or application specific integrated circuits.

[0154] The wireless circuit 1608 is used to transmit and receive information over a wireless link or network to conventional circuits of one or more other devices, such as an antenna system, a radio frequency (RF) transceiver, one or more amplifiers, a tuner, one or more oscillators, a digital signal processor, a codec (CODEC) chipset, memory, etc. The wireless circuit 1608 may use various protocols, such as those described herein. In various embodiments, the wireless circuit 1608 is capable of establishing and maintaining communications with other devices using one or more communication protocols including time division multiple access (TDMA), code division multiple access (CDMA), global system for mobile communications (GSM), enhanced data GSM environment (EDGE), wideband code division multiple access (W-CDMA), LTE, advanced long term evolution (LTE), Wi-Fi (such as Institute of Electrical and Electronics Engineers (IEEE) 802.11a, IEEE802.11b, IEEE 802.11g and / or IEEE 802.11n), Bluetooth, Wi-MAX, voice over Internet protocol (VoIP), near field communication protocol (NFC), protocols for email, instant messaging and / or short message service (SMS), or any other suitable communication protocol, including communication protocols that have not been developed as of the filing date of this document.

[0155] The wireless circuit 1608 is coupled to the processing system 1604 via the peripherals interface 1616. The peripherals interface 1616 may include conventional components for establishing and maintaining communications between peripherals and the processing system 1604. Voice and data information received by the wireless circuit 1608 (e.g., in voice recognition or voice command applications) is transmitted to the one or more processors 1618 via the peripherals interface 1616. The one or more processors 1618 can be configured to process various data formats of the one or more applications 1634 stored on the medium 1602.

[0156] The peripheral device interface 1616 couples the input peripheral devices and output peripheral devices of the device 1600 to one or more processors 1618 and the computer readable medium 1602. The one or more processors 1618 communicate with the computer readable medium 1602 via the controller 1620. The computer readable medium 1602 can be any device or medium capable of storing code and / or data for use by one or more processors 1618. The computer readable medium 1602 may include a memory hierarchy, including a cache, a main memory, and an auxiliary memory. The memory hierarchy can be implemented using any combination of random access memory (RAM) (e.g., static random access memory (SRAM), dynamic random access memory (DRAM), double data random access memory (DDRAM)), read-only memory (ROM), flash memory, magnetic storage devices, and / or optical storage devices (such as disk drives, tapes, CDs (optical disks), and DVDs (digital video disks)). In some embodiments, the peripheral device interface 1616, one or more processors 1618, and the controller 1620 can be implemented on a single chip such as the processing system 1604. In some other examples, they may be implemented on separate chips.

[0157] Processor 1618 may include hardware and / or software elements that perform one or more processing functions, such as mathematical operations, logical operations, data manipulation operations, data transfer operations, control the receipt of user input, control the output of information to a user, etc. Processor 1618 may be embodied as one or more hardware processors, microprocessors, microcontrollers, field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), etc.

[0158] Device 1600 also includes a power system 1642 for powering the various hardware components. Power system 1642 may include a power management system, one or more power sources (e.g., batteries, alternating current (AC)), a recharging system, a power failure detection circuit, a power converter or inverter, a power status indicator (e.g., a light emitting diode (LED)), and any other components typically associated with the generation, management, and distribution of electricity in a mobile device.

[0159] In some embodiments, device 1600 includes camera 1644. In some embodiments, device 1600 includes sensor 1646. Sensors can include accelerometers, compasses, gyroscopes, pressure sensors, audio sensors, light sensors, barometers, etc. Sensor 1646 can be used to sense aspects of a location, such as auditory markers or light signatures of a location.

[0160] In some embodiments, the device 1600 may include a GPS receiver, sometimes referred to as a GPS unit 1648. The mobile device may use a satellite navigation system such as a global positioning system (GPS) to obtain positioning information, timing information, altitude, or other navigation information. During operation, the GPS unit may receive signals from GPS satellites flying around the earth. The GPS unit analyzes the signals to estimate the transmission time and distance. The GPS unit may determine the current location (current position) of the mobile device. Based on these estimates, the mobile device may determine the position, altitude, and / or current speed. The position may be a geographic coordinate, such as latitude information and longitude information.

[0161] The one or more processors 1618 execute various software components stored in the medium 1602 to perform various functions of the device 1600. In some embodiments, the software components include an operating system 1622, a communication module 1624 (or an instruction set), a location module 1626 (or an instruction set), a ranging module 1628 used as part of the ranging operations described herein, and other applications 1634 (or an instruction set).

[0162] The operating system 1622 may be any suitable operating system, including iOS, Mac OS, Darwin, a real-time operating system (RTXC), LINUX, UNIX, OS X, WINDOWS, or an embedded operating system such as VxWorks. The operating system may include various programs, instruction sets, software components, and / or drivers for controlling and managing general system tasks (e.g., memory management, storage device control, power management, etc.), and facilitate communication between various hardware and software components.

[0163] Communications module 1624 facilitates communication with other devices through one or more external ports 1636 or via wireless circuitry 1608, and includes various software components for processing data received from wireless circuitry 1608 and / or external ports 1636. External ports 1636 (e.g., Universal Serial Bus (USB), FireWire, Lightning connector, 60-pin connector, etc.) are suitable for coupling to other devices directly or indirectly through a network (e.g., the Internet, a wireless local area network (LAN), etc.).

[0164] The location / motion module 1626 can help determine the current location (e.g., coordinates or other geographic location identifiers) and movement of the device 1600. Modern positioning systems include satellite-based positioning systems such as the Global Positioning System (GPS), cellular network positioning based on "cell IDs," and Wi-Fi positioning technology based on Wi-Fi networks. GPS also relies on the visibility of multiple satellites to determine location estimates, which may not be visible (or have weak signals) indoors or in "urban canyons." In some embodiments, the location / motion module 1626 receives data from the GPS unit 1648 and analyzes the signals to determine the current location of the mobile device. In some embodiments, the location / motion module 1626 can use Wi-Fi or cellular location technology to determine the current location. For example, the location of the mobile device can be estimated using knowledge of nearby cell locations and / or Wi-Fi access points and knowledge of their locations. Information identifying the Wi-Fi or cellular transmitter is received at the wireless circuit 1608 and transmitted to the location / motion module 1626. In some embodiments, the location module receives one or more transmitter IDs. In some embodiments, the sequence of transmitter IDs can be compared to a reference database (e.g., a cell ID database, a Wi-Fi reference database) that maps or associates transmitter IDs to location coordinates of corresponding transmitters, and based on the location coordinates of the corresponding transmitters, an estimated location coordinate of the device 1600 is calculated. Regardless of the particular positioning technology used, the position / motion module 1626 receives information from which a position fix can be derived, interprets the information, and returns position information, such as geographic coordinates, latitude / longitude, or other position fix data.

[0165] The ranging module 1628 can transmit / receive ranging messages to / from, for example, an antenna connected to the wireless circuit 1608. These messages can be used for various purposes, such as for identifying the transmitting antenna of the device, determining the timestamp of the message to determine the distance between the mobile device 1600 and another device. The ranging module 1628 can be present on various processors of the device, such as an always-on processor (AOP), a UWB chip, and / or an application processor. For example, a component of the ranging module 1628 can determine the distance on the AOP, and another component of the ranging module can interact with a sharing module, such as to display the location of another device on the screen so that the user selects another device to share data items. The ranging module 1628 can also interact with a reminder module, which can provide an alarm based on the distance from another mobile device.

[0166] The one or more applications 1634 on the device 1600 may include any application installed on the device 1600, including but not limited to a browser, an address book, a contact list, email, instant messaging, social networking, word processing, keyboard emulation, widgets, JAVA-enabled applications, encryption, digital rights management, voice recognition, voice replication, a music player (for playing back recorded music stored in one or more files such as MP3 or AAC files), and the like.

[0167] There may be other modules or instruction sets (not shown), such as a graphics module, a time module, and the like. For example, the graphics module may include various conventional software components for rendering, animating, and displaying graphical objects (including but not limited to text, web pages, icons, digital images, animations, and the like) on a display surface. In another example, the timer module may be a software timer. The timer module may also be implemented in hardware. The timer module may maintain various timers for any number of events.

[0168] I / O subsystem 1606 may be coupled to a display system (not shown) which may be a touch-sensitive display. The display displays visual output to the user in the GUI. The visual output may include text, graphics, video, and any combination thereof. Some or all of the visual outputs may correspond to user interface objects. Although the display may use light emitting diode (LED), liquid crystal display (LCD), or light emitting polymer display (LPD) technology, other display technologies may be used in other embodiments.

[0169] In some embodiments, I / O subsystem 1606 may include a display and user input devices such as keyboard, mouse and / or touch pad. In some embodiments, I / O subsystem 1606 may include a touch-sensitive display. The touch-sensitive display may also accept input from the user based at least in part on tactile and / or tactile contact. In some embodiments, the touch-sensitive display forms a touch-sensitive surface for accepting user input. The touch-sensitive display / surface (together with any associated modules and / or instruction sets in computer-readable medium 1602) detects contact (and any movement or release of contact) on the touch-sensitive display, and converts the detected contact into interaction with a user interface object, such as one or more soft keys displayed on a touch screen when contact occurs. In some embodiments, the contact point between the touch-sensitive display and the user corresponds to one or more fingers of the user. The user may contact the touch-sensitive display using any suitable object or attachment such as a stylus, pen, finger, etc. The touch-sensitive display surface can use any suitable touch-sensitive technology to detect contact and any movement or release thereof, including capacitive technology, resistive technology, infrared technology, and surface acoustic wave technology, as well as other proximity sensor arrays or other elements for determining one or more points of contact with the touch-sensitive display.

[0170] In addition, the I / O subsystem 1606 may also be coupled to one or more other physical control devices (not shown), such as buttons, keys, switches, rocker buttons, dials, slide switches, joysticks, LEDs, etc., for controlling or performing various functions, such as power control, speaker volume control, ring volume, keyboard input, scrolling, holding, menus, lock screen, clearing and ending communications, etc. In some embodiments, in addition to the touch screen, the device 1600 may include a touch pad (not shown) for activating or deactivating specific functions. In some embodiments, the touch pad is a touch-sensitive area of ​​the device that, unlike a touch screen, does not display visual output. The touch pad may be a touch-sensitive surface separate from a touch-sensitive display or an extension of a touch-sensitive surface formed by the touch-sensitive display.

[0171] In some embodiments, an application executed on a user's device may be used to perform some or all of the operations described herein. Circuits, logic modules, processors, and / or other components may be configured to perform the various operations described herein. It should be understood by those skilled in the art that such configurations may be accomplished by design, setup, interconnection, and / or programming of specific components, depending on the specific implementation, and again depending on the specific implementation, the configured components may be reconfigurable or not reconfigurable for different operations. For example, a programmable processor may be configured by providing appropriate executable code; a dedicated logic circuit may be configured by appropriately connecting logic gates and other circuit elements; and so on.

[0172] Any software component or function described in this patent application can be implemented as a software code executed by a processor, and the processor uses any suitable computer language, such as, for example, Java, C, C++, C#, Objective-C, Swift, or a scripting language such as Perl or Python using, for example, conventional or object-oriented techniques. The software code can be stored on a computer-readable medium as a series of instructions or commands to achieve storage and / or transmission. Suitable non-transient computer-readable media may include random access memory (RAM), read-only memory (ROM), magnetic media (such as a hard drive or floppy disk), or optical media (such as a compact disk (CD) or DVD (digital versatile disk)), flash memory, etc. The computer-readable medium may be any combination of such storage devices or transmission devices.

[0173] The computer program incorporating the various features of the present disclosure may be encoded on various computer-readable storage media; suitable media include disks or tapes, optical storage media, such as compact disks (CDs) or DVDs (digital versatile disks), flash memory, etc. The computer-readable storage medium encoded with the program code may be packaged with a compatible device or provided separately from other devices. In addition, the program code may be encoded and sent via wired optical and / or wireless networks (including the Internet) that conform to a variety of protocols, thereby allowing distribution, for example, via Internet downloads. Any such computer-readable medium may reside on or within a single computer product (e.g., a solid-state drive, a hard drive, a CD, or an entire computer system), and may be present on or within different computer products within a system or network. The computer system may include a monitor, a printer, or other suitable displays for providing any results mentioned herein to a user.

[0174] As described above, one aspect of the technology of the present invention is to collect, share and use data, including authentication tags and data derived from the tags. The present disclosure contemplates that, in some cases, these collected data may include personal information data that uniquely identifies or can be used to contact or locate a specific person. Such personal information data may include demographic data, location-based data, phone numbers, email addresses, twitter IDs, home addresses, data or records related to the user's health or fitness level (e.g., vital sign measurements, medication information, exercise information), date of birth, or any other identifying information or personal information.

[0175] The present disclosure recognizes that the use of such personal information data in the present technology can be used to benefit the user. For example, the personal information data can be used to authenticate another device and vice versa to control which device ranging operations can be performed. In addition, the present disclosure also anticipates other uses of personal information data that benefit the user. For example, health and fitness data can be shared to provide insights into the user's overall health status, or can be used as positive feedback to individuals using technology to pursue health goals.

[0176] The disclosure anticipates that entities responsible for the collection, analysis, disclosure, transmission, storage or other purposes of such personal information data will comply with sound privacy policies and / or privacy measures. Specifically, such entities should implement and adhere to the use of privacy policies and practices that are recognized as meeting or exceeding the industry or government requirements for maintaining the privacy and security of personal information data. Such policies should be easy for users to access and should be updated as changes in the collection and / or use of data occur. Personal information from users should be collected for legal and reasonable entity purposes and should not be shared or sold outside these legal purposes. In addition, such collection / sharing should be carried out after receiving the user's informed consent. In addition, such entities should consider taking any necessary steps to protect and safeguard access to such personal information data and ensure that other entities with access to personal information data comply with their privacy policies and procedures. In addition, such entities can subject themselves to third-party assessments to prove that they comply with widely accepted privacy policies and practices. In addition, policies and practices should be adapted to specific types of personal information data collected and / or accessed, and to applicable laws and standards including considerations of special jurisdictions. For example, in the United States, the collection or acquisition of certain health data may be governed by federal and / or state laws, such as the Health Insurance Portability and Accountability Act (HIPAA); while health data in other countries may be subject to other regulations and policies and should be handled accordingly. Therefore, different privacy measures should be advocated for different types of personal data in each country.

[0177] Regardless of the foregoing, the present disclosure also contemplates implementation schemes in which users selectively block the use or access of personal information data. That is, the present disclosure contemplates hardware elements and / or software elements to prevent or block access to such personal information data. For example, with respect to sharing content and performing ranging, the technology of the present invention may be configured to allow users to choose to "opt in" or "opt out" to participate in the collection of personal information data at any time during or after registration for a service. In addition to providing "opt-in" and "opt-out" options, the present disclosure also contemplates providing notifications related to access or use of personal information. For example, a user may be notified that their personal information data will be accessed when downloading an application, and then reminded again just before the personal information data is accessed by the application.

[0178] In addition, the intention of the present disclosure is that personal information data should be managed and processed in a manner that minimizes the risk of unintentional or unauthorized access or use. Once the data is no longer needed, the risk can be minimized by limiting data collection and data deletion. In addition, and when applicable, including in certain health-related applications, data de-identification can be used to protect the privacy of the user. De-identification can be promoted when appropriate by removing specific identifiers (e.g., date of birth, etc.), controlling the amount or specificity of stored data (e.g., collecting location data at the city level rather than at the address level), controlling how the data is stored (e.g., aggregating data between users), and / or other methods.

[0179] Therefore, while the present disclosure broadly covers the use of personal information data to implement one or more of the various disclosed embodiments, the present disclosure also contemplates that various embodiments may be implemented without access to such personal information data. That is, various embodiments of the present technology will not fail to function properly due to the lack of all or part of such personal information data.

[0180] Although the disclosure has been described with respect to specific embodiments, it should be understood that the disclosure is intended to cover all modifications and equivalents coming within the scope of the following claims.

[0181] All patents, patent applications, publications, and specifications mentioned herein are incorporated by reference in their entirety for all purposes. No admission is made that any document is prior art.

[0182] Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense. It will, however, be evident that various modifications and changes may be made thereto without departing from the broader spirit and scope of the present disclosure as set forth in the claims.

[0183] Other variations are within the spirit of the present disclosure. Thus, while the disclosed technology is susceptible to various modifications and alternative constructions, certain illustrative embodiments thereof are shown in the drawings and have been described in detail above. However, it should be understood that it is not intended to limit the present disclosure to the particular forms disclosed, but on the contrary, it is intended to cover all modifications, alternative constructions, and equivalent forms that fall within the spirit and scope of the present disclosure as defined by the appended claims.

[0184] The use of the terms "one" and "an" and "the" and similar indicators in the context of describing the disclosed embodiments (particularly in the context of the following claims) will be interpreted as covering the singular and plural, unless otherwise stated or clearly contradicted by the context. Unless otherwise stated, the terms "comprising", "having", "including" and "containing" should be interpreted as open terms (i.e., meaning "including but not limited to"). The term "connected" is interpreted as being partially or completely included, attached or joined together even if there are intervening things. The phrase "based on" should be understood as open, and is not limited in any way, and is intended to be interpreted or otherwise understood as "based at least in part" where appropriate. Unless otherwise stated herein, the description of the numerical range herein is intended only to be used as a simple method of referring to each individual value falling within the range individually, and each individual value is incorporated into the specification, as if quoted separately in this article. All methods described herein can be performed in any suitable order, unless otherwise stated herein or otherwise clearly contradicted by the context. Unless otherwise stated, the use of any and all examples or exemplary language (e.g., "such as") provided herein is intended only to better illustrate the embodiments of the present disclosure and does not limit the scope of the present disclosure. Any language in the specification should not be interpreted as indicating that any undeclared element is essential to the practice of the present disclosure. Unless explicitly indicated to the contrary, the use of "or" is intended to mean "inclusive or" rather than "exclusive or". Mentioning a "first" component does not necessarily require that a second component be provided. In addition, unless explicitly stated, reference to a "first" component or a "second" component does not limit the components mentioned to a specific location. The term "based on" is intended to mean "based at least in part on".

[0185] Unless otherwise specifically stated, disjunctive language such as the phrase "at least one of X, Y, or Z" is understood in context as generally used to present an item, term, etc., which can be X, Y, or Z, or any combination thereof (e.g., X, Y, and / or Z). Thus, such disjunctive language is generally not intended to, and should not, imply that certain embodiments require that at least one of X, at least one of Y, or at least one of Z each be present. Additionally, conjunctive language such as the phrase "at least one of X, Y, and Z" is also understood to mean X, Y, Z, or any combination thereof, including "X, Y, and / or Z," unless otherwise specifically stated.

[0186] Preferred embodiments of the present disclosure are described herein, including the best mode known to the inventor for carrying out the present disclosure. After reading the foregoing description, variations of those preferred embodiments may become apparent to those of ordinary skill in the art. The inventor expects that the technical staff will appropriately adopt such variations, and the inventor intends to practice the present disclosure in a manner different from that specifically described herein. Therefore, as permitted by applicable law, the present disclosure includes all modifications and equivalents of the subject matter recorded in the claims attached to the present disclosure. In addition, unless otherwise noted herein or obviously contradictory to the context, the present disclosure includes any combination of all possible variations of the above-mentioned elements.

[0187] All references, including publications, patent applications, and patents, cited herein are hereby incorporated by reference to the same extent as if each reference were individually and specifically indicated to be incorporated by reference and were set forth in its entirety herein.

Claims

1. A method for communicating with an access device, the method comprising executing, by a mobile device: receiving a plurality of polling messages, each polling message including an identifier of a particular access device among a plurality of access devices that sent the polling message, wherein each polling message of the plurality of polling messages is sent during a polling phase; selecting a time slot from among a plurality of time slots during a response phase of a communication session; sending a response message during said time slot of said response phase; receiving an assignment message during a third phase, the assignment message comprising an assigned time slot for a response phase of a future session; performing secure ranging with one or more access devices of the plurality of access devices during the future session using the assigned time slot; as well as Access credentials are provided to the one or more access devices based on the location determined using the secure ranging.

2. The method according to claim 1, further comprising: A portion of the time slot is selected based on arrival times of the plurality of polling messages, and wherein the response message is sent during the portion of the time slot.

3. The method according to any one of claims 1 to 2, further comprising: A portion of the time slot is selected based on a received message strength of each of the plurality of polling messages, and wherein the response message is sent during the portion of the time slot.

4. The method according to any one of claims 1 to 3, further comprising: Scheduling information is received, the scheduling information specifying which portion of each of the plurality of time slots is assigned to which access device to listen for the response message.

5. The method according to any one of claims 1 to 4, wherein the scheduling information is received in a polling message.

6. The method according to any one of claims 1 to 5, wherein the time slot comprises a plurality of parts, wherein each part of the time slot corresponds to a respective access device among the plurality of access devices.

7. The method according to any one of claims 1 to 6, wherein the response message comprises a public key of the mobile device.

8. The method according to any one of claims 1 to 7, wherein the assignment message comprises an access device public key.

9. The method according to any one of claims 1 to 8, wherein the assignment message includes instructions for performing secure ranging with a designated access device among the plurality of access devices.

10. A method for secure distance measurement, comprising: receiving one or more assignment messages from one or more access devices of the plurality of access devices, the one or more assignment messages identifying a first assigned response time slot of a plurality of response time slots for a response phase of a future ranging session; Receiving a polling message from each access device of the plurality of access devices, each polling message including access device identification information; Determining a reception time of the polling message by at least one access device among the plurality of access devices; as well as sending a first response message during the first assigned response time slot, the first response message comprising a mobile device identifier and timing information, the timing information corresponding to one or more reception times of at least one of the polling messages for at least one of the one or more access devices; receiving an access message from a first access device among the plurality of access devices; as well as In response to the access message, access credentials are provided to the first access device.

11. The method of claim 10, wherein the timing information comprises a response time comprising a difference between the reception time of the polling message and the transmission time of the first response message.

12. The method according to any one of claims 10 to 11, wherein the access message comprises a trigger message instructing the mobile device to provide the access credentials.

13. The method according to any one of claims 10 to 12, wherein the access message comprises information indicating a distance between the mobile device and the first access device, and wherein the access credential is provided to the first access device based on the information indicating the distance.

14. The method according to any one of claims 10 to 13, wherein the information indicative of the distance comprises the distance determined by the first access device.

15. The method according to any one of claims 10 to 14, wherein the first response message is encrypted using a public key of the access device.

16. The method of any one of claims 10 to 15, further comprising decrypting the access message using a private key of the mobile device. 17 . The method according to claim 10 , wherein the mobile device performs the secure ranging with the first access device and the second access device among the plurality of access devices.

18. The method of any one of claims 10 to 17, wherein the one or more assignment messages identify a second assigned response time slot of the plurality of response time slots, the second assigned response time slot corresponding to the second access device.

19. The method according to any one of claims 10 to 18, further comprising: A second response message is sent to the second access device during the second assigned response time slot.

20. The method according to any one of claims 10 to 19, wherein the first response message is sent to a passive receiver of the first access device.

21. A method according to any one of claims 10 to 20, wherein the access credentials are provided to a passive receiver of the first access device.

22. A computing device for communicating with an access device, the computing device comprising: one or more memories; and One or more processors in communication with the one or more memories and configured to execute instructions stored in the one or more memories to perform any of the methods of claims 1 to 9.

23. A computing device for safe distance measurement, the computing device comprising: one or more memories; and One or more processors in communication with the one or more memories and configured to execute instructions stored in the one or more memories to perform any of the methods of claims 10 to 21.

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