Anti-interference UWB communication system

Abstract

In one embodiment, an apparatus includes a first radio controller configured to communicate using a first protocol; and a pseudo-random number generator configured to generate a pseudo-random output value based on the input data value. The apparatus includes a processor configured to determine a preamble based on an output of the pseudo-random number generator, and process a data packet received using the first radio controller using the preamble to generate a processed data packet.

Description

Technical Field

[0001] The present disclosure relates generally to systems and methods configured to implement a robust ultra-wideband (UWB) communication protocol, and more particularly to systems and methods configured to select preamble communication codes in an unpredictable manner to perform UWB communications that are resistant to communication interference. Background Art

[0002] Radio frequency (RF) based communication systems may be susceptible to communication jamming attacks in which a malicious user broadcasts a signal in a communication channel to prevent or hinder communications between legitimate devices. In the case of ultra-wideband (UWB) communications, such an attack may be successful if the malicious signal looks like the signal expected by the receiver device and the signal arrives at the receiver device with a higher power than the desired signal. For example, a low-cost, low-power jammer may continuously transmit a signal including a preamble sequence required for signal acquisition and synchronization by the receiver device. In this case, the probability that the receiver device will synchronize its communication function with the jamming signal instead of the desired signal may be relatively high. This may result in the expected communication being blocked.

[0003] UWB can be used to implement location services, enabling participating devices to determine their location or the location of other devices via a real-time location system (RTLS) to perform various functions. For example, the location of the device can be used to provide navigation or other location-driven services. If the UWB communication utilized in the implementation of the location service is interfered with by a malicious signal in the manner described above, the location service may become unavailable, resulting in a possible loss of system functionality. Summary of the invention

[0004] The Summary of the Invention section is neither intended nor should it be interpreted as representing the entire span and scope of the present disclosure. Additional benefits, features, and embodiments of the present disclosure are set forth in the accompanying drawings and the description below, and as described in the claims. Therefore, it should be understood that the Summary of the Invention section may not include all aspects and embodiments claimed herein.

[0005] Furthermore, the disclosure herein is not intended to be limiting or definitive in any way. Furthermore, the disclosure is intended to provide one of ordinary skill in the art with an understanding of one or more representative embodiments supporting the claims. Therefore, it is important that the claims be considered to have a scope of constructions that include the various features of the disclosure, as long as they do not depart from the scope of methods and devices consistent with the disclosure (including the claims originally filed). Furthermore, the disclosure is intended to cover and include obvious improvements and modifications of the disclosure.

[0006] According to a first aspect of the present invention, there is provided a system comprising:

[0007] a plurality of ultra-wideband (UWB) anchor points configured to broadcast UWB timing data in a plurality of data packets, wherein each data packet is associated with a preamble; and

[0008] Device, the device comprising:

[0009] a first radio controller configured to communicate with the plurality of UWB anchor points using a first protocol,

[0010] a pseudo-random number generator configured to generate a pseudo-random output value based on an input data value; and

[0011] A processor configured to:

[0012] providing the input data value to the pseudo-random number generator so that the pseudo-random number generator outputs the pseudo-random output value;

[0013] Determine a preamble using the pseudo-random output value;

[0014] processing a data packet received using the first radio controller and from a first UWB anchor point of the plurality of UWB anchor points using the preamble to generate a processed data packet; and

[0015] The location of the device is determined using the processed data packets.

[0016] In one or more embodiments, the apparatus includes a second radio controller configured to communicate using a second protocol, wherein the second protocol is not a UWB communication protocol.

[0017] In one or more embodiments, the processor is configured to receive a first configuration parameter using the second radio controller, wherein the first configuration parameter indicates a mapping of a pseudo-random output value of the pseudo-random number generator to a preamble.

[0018] In one or more embodiments, the processor is configured to receive second configuration parameters using the second radio controller, wherein the second configuration parameters determine a configuration of the pseudo-random number generator.

[0019] In one or more embodiments, the processor is configured to determine a current preamble hopping state value, and the preamble hopping state value is equal to the input data value provided to the pseudo-random number generator.

[0020] In one or more embodiments, the first protocol subdivides the communication operation into a plurality of sequential time slots, and the processor is configured to increment the preamble hopping state value after each subsequent time slot occurs.

[0021] In one or more embodiments, when the apparatus is not time synchronized with the plurality of UWB anchor points, the processor is configured to:

[0022] Determining a first preamble from a plurality of preambles, wherein the plurality of preambles are determined according to the first protocol;

[0023] Repeating the first preamble to attempt to decode ranging start messages or ranging synchronization messages received from the plurality of UWB anchor points; and

[0024] After successfully decoding a first ranging start message or a ranging synchronization message using the first preamble, current preamble hopping state values ​​of the plurality of UWB anchor points are determined.

[0025] In one or more embodiments, the first preamble code is a fixed value.

[0026] In one or more embodiments, the first preamble is pseudo-randomly determined.

[0027] According to a second aspect of the present invention, there is provided an apparatus comprising:

[0028] a first radio controller configured to communicate using a first protocol;

[0029] a pseudo-random number generator configured to generate a pseudo-random output value based on an input data value; and

[0030] A processor configured to:

[0031] determining a preamble based on an output of the pseudo-random number generator; and

[0032] A data packet received using the first radio controller is processed using the preamble to generate a processed data packet.

[0033] In one or more embodiments, the apparatus includes a second radio controller configured to communicate using a second protocol.

[0034] In one or more embodiments, the processor is configured to receive configuration parameters using the second radio controller, the configuration parameters determining a configuration of the pseudo-random number generator.

[0035] In one or more embodiments, the processor is configured to determine a current preamble hopping state value, and the preamble hopping state value is equal to the input data value provided to the pseudo-random number generator.

[0036] In one or more embodiments, the first protocol subdivides the communication operation into a plurality of sequential time slots, and the processor is configured to increment the preamble hopping state value after each subsequent time slot occurs.

[0037] According to a third aspect of the present invention, there is provided a method comprising:

[0038] providing an input data value to a pseudo-random number generator so that the pseudo-random number generator outputs a pseudo-random output value;

[0039] using the pseudo-random output value as an input to a pseudo-random number generator to determine a preamble;

[0040] processing a data packet received using a first radio controller configured to communicate using a first communication protocol using the preamble to generate a processed data packet; and

[0041] The location of the device is determined using the processed data packets.

[0042] In one or more embodiments, the method additionally includes receiving, using a second radio controller configured to communicate using a second communication protocol, a first configuration parameter, wherein the first configuration parameter indicates a mapping of a pseudo-random output value of the pseudo-random number generator to a preamble.

[0043] In one or more embodiments, the method further comprises receiving, using the second radio controller, second configuration parameters, wherein the second configuration parameters determine a configuration of the pseudo-random number generator.

[0044] In one or more embodiments, the method further includes determining a current preamble hopping state value, and the current preamble hopping state value is equal to the input data value provided to the pseudo-random number generator.

[0045] In one or more embodiments, the first protocol subdivides the communication operation into a plurality of sequential time slots, and the method further includes incrementing the preamble hopping state value after each subsequent time slot occurs.

[0046] In one or more embodiments, the method further comprises:

[0047] Determining a first preamble from a plurality of preambles, wherein the plurality of preambles are determined according to the first protocol;

[0048] reusing the first preamble to attempt to decode a message received using the first radio controller; and

[0049] After successfully decoding the first message using the first preamble, a current preamble hopping state is determined.

[0050] These and other aspects of the invention will be apparent from and elucidated with reference to the embodiments described hereinafter. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] The accompanying drawings are included to provide a further understanding of the present disclosure and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the present disclosure and together with the description serve to explain the principles of the present disclosure.

[0052] In the attached picture:

[0053] Figure 1 Describes an example of a real-time location system (RTLS) for wireless location.

[0054] Figure 2 An apparatus configured to implement the preamble selection scheme of the present disclosure is depicted.

[0055] Figure 3 Depicting a breakdown of the timeline of UWB communication broken down into blocks, rounds, and time slots.

[0056] Figure 4 is a flow chart depicting a method for performing preamble selection according to the present disclosure.

[0057] Figure 5 is a flow chart depicting a method for a device participating in UWB communications to determine a current preamble hopping state for future communications during a communication timeslot.

[0058] Figure 6 is a flow chart depicting a method that may be implemented by a device participating in a UWB network according to the present disclosure. DETAILED DESCRIPTION

[0059] The present disclosure relates generally to systems and methods configured to implement an ultra-wideband (UWB) communication protocol, and more particularly to systems and methods configured to modify a preamble communication code in an unpredictable manner to perform UWB communications that are resistant to communication interference.

[0060] As described herein, UWB communication may refer to a radio technology that can communicate over a large portion of the radio spectrum using low energy levels for short-range, high-bandwidth communications. Additionally, UWB may refer to a technology for transmitting information spread over a large bandwidth (e.g., approximately 500 MHz or greater). In some embodiments, UWB may be defined as a wireless transmission whose transmitted signal bandwidth exceeds less than 500 MHz or 20% of the signal's arithmetic center frequency. In some embodiments, UWB communication may involve transmitting information by generating electronic energy at radio frequencies at specific time intervals and occupying a large bandwidth, thereby implementing pulse positioning modulation.

[0061] The UWB positioning and ranging system can also use the time-of-flight principle to determine the distance between the positioning device, the personal communication device and / or the UWB anchor point. In some embodiments, the transmitter of the transceiver (associated with the positioning device) sends out a waveform, usually a chirp or a pulse, which is either reflected by the object or retransmitted by the second transceiver. Based on the amount of time it takes for the reflection or retransmission to reach the receiver of the initiating transceiver, the distance between the objects can be calculated. The calculated distance between the receiver and the transmitter can then be used to determine the position, so that the position can be used to perform additional positioning-related functions.

[0062] Figure 1 An example of a real-time location system (RTLS) 100 for wireless location is depicted. Figure 1 In the depicted embodiment, RTLS 100 includes a positioning device 102 that wirelessly communicates with four UWB anchor devices (anchor 104-1, anchor 104-2, anchor 104-3, and anchor 104-4). RTLS 100 can be used in a variety of applications, such as industrial applications, medical applications, computer applications, and / or consumer or enterprise applications. In some embodiments, RTLS 100 is a wireless positioning system, such as a wireless positioning system compatible with the Institute of Electrical and Electronics Engineers (IEEE) 802.15.4 protocol. For example, RTLS 100 can be a wireless positioning system compatible with the IEEE802.15.4z standard. Although RTLS 100 is not limited to wireless positioning systems in the Figure 1 Although shown as having certain components and described herein as having certain functionality, other embodiments of RTLS 100 may include fewer or more components to implement the same, fewer, or more functionality. In another example, although RTLS Figure 1 The network topology of RTLS is shown as connected in a certain topology, but the network topology of RTLS is not limited to Figure 1 The topology shown.

[0063] exist Figure 1In the depicted embodiment, the positioning device 102 may be a mobile device (e.g., a mobile phone, a smart watch, a tablet computer, a laptop computer, etc.). In addition, the positioning device 102 may be a UWB-enabled device such that a UWB radio device and a positioning engine are implemented in the positioning device 102. The UWB radio device and / or the positioning engine of the positioning device 102 may be implemented in hardware (e.g., circuitry), software, firmware, or a combination thereof. The UWB radio device and / or the positioning engine of the positioning device 102 may be implemented in whole or in part as an integrated circuit (IC) device. In some embodiments, the UWB radio device and / or the positioning engine may be compatible with at least one UWB wireless protocol (e.g., at least one IEEE 802.15.4 protocol). For example, the UWB radio device and / or the positioning engine may be compatible with the IEEE 802.15.4z protocol.

[0064] In some embodiments, the UWB radio device is a wireless UWB radio device that is wirelessly connected to a UWB anchor point, for example, via one or more UWB wireless protocols (e.g., IEEE802.15.4 protocol). In some embodiments, the UWB radio device includes at least one antenna, at least one transceiver operably connected to the at least one antenna, and at least one processor operably connected to the corresponding transceiver. In some embodiments, the at least one transceiver includes a physical layer (PHY) device. The at least one processor can be configured to control the at least one transceiver to process packets (e.g., flash packets) received via the at least one antenna. In some embodiments, the at least one processor is implemented in a processor such as a microcontroller (MCU), a host processor, a host, a digital signal processor (DSP), or a central processing unit (CPU), and the processor can be integrated in the corresponding transceiver.

[0065] exist Figure 1 In the depicted embodiment, UWB anchor points (e.g., anchor point 104-1, anchor point 104-2, anchor point 104-3, and anchor point 104-4) may be associated with (e.g., connected to) a positioning device (e.g., positioning device 102) and may communicate with the positioning device via UWB communication. Figure 1104-1, 104-2, 104-3, and 104-4) may each be connected via a network 120. The network 120 may involve each UWB anchor in the RTLS 100 being connected via, for example, Ethernet and / or Wi-Fi to achieve anchor synchronization. Alternatively, anchor synchronization may occur using in-band UWB communication between anchor devices. Anchor synchronization allows the RTLS 100 to exchange time-specific data (e.g., UWB timing data), which may be further used to provide an accurate, real-time location of the positioning device 102. In this embodiment, the UWB anchor point may be connected (e.g., wirelessly connected) to a UWB radio device (shown by dashed line 122) of the positioning device 102 using a UWB wireless protocol, so that the UWB radio device may acquire UWB timing data via at least one blink packet transmitted by each UWB anchor point using the UWB wireless protocol. For example, each UWB anchor point may transmit a blink packet including information corresponding to the corresponding UWB anchor point.

[0066] refer to Figure 1 , the positioning device 102 can perform each functionality required for wireless positioning in the RTLS 100. For example, the UWB radio of the positioning device can obtain UWB timing data from a UWB anchor point, the positioning engine can use the UWB timing data to determine the position of the positioning device 102, and the position of the positioning device 102 can be used by the positioning device to display the position of the positioning device or determine the function to be performed, for example, via a UI (shown by the mapping image 126). In this embodiment, the positioning device 102 uses UWB communication and UWB timing data captured by the positioning device from the UWB anchor point to determine its own position. Therefore, when the positioning device lacks one or more functionalities required for wireless positioning, the RTLS may not be able to perform wireless positioning. In addition, because the positioning device may lack UWB capabilities, computing power and / or UI, it may not be possible to implement each functionality using a single device.

[0067] Many RF communication systems are susceptible to communication jamming attacks, in which a malicious user introduces a signal into a communication channel to prevent or hinder communication between legitimate devices. In the case of UWB communications, such an attack can be successful if the jamming signal looks like the signal that the receiver expects (i.e., the desired signal) and arrives at the attacked receiver with a higher power than the desired signal. For example, a low-cost, low-power jammer can continuously transmit the sequence required by the receiver for signal acquisition and synchronization. Then, the victim device in the vicinity of the jammer will most likely synchronize with the jammer's jamming signal instead of the desired signal, thereby preventing the intended communication.

[0068] In the specific example of signal jamming, a particular jammer placement could completely disrupt the location services in some UWB location systems (e.g., a denial of service attack). If the jammer signal reaches several listening nodes at a higher power than the real signal (e.g., Figure 1 In this case, the interfering signal can create a large geographic area (called a "shadow area") where the positioning service cannot operate.

[0069] To mitigate these potential problems that may be caused by jamming activities in UWB communication systems, the present disclosure provides a mitigation method that significantly increases the difficulty of such jamming attacks. Therefore, the present disclosure provides systems and methods for communication systems that can increase the availability of UWB systems used in critical applications (e.g., positioning servers that may include secure ranging services).

[0070] UWB communication systems rely on preliminary network configuration steps that enable participating devices to obtain the necessary device configuration parameters to operate on the UWB network. Typically, these configuration parameters are exchanged by an out-of-band communication channel (i.e., a communication channel that is not part of the UWB network being configured or set up).

[0071] Among the configuration parameters exchanged as part of this preliminary setup step are the selected channel (e.g., channel 9) and the preamble. The correct setting of these parameters ensures that different UWB systems can coexist near each other without undesirable disturbances. After the configuration parameters are set, for example, unused preambles with low cross-correlation are available in the set of available preambles and can be used to increase communication resilience against communication interference. As described herein, the current system is configured to use these unused preambles to improve the resistance of the UWB system to preamble repetition interference.

[0072] Specifically, participant devices in the network are configured to pseudo-randomly change the preamble of packet transmissions occurring on the UWB network so that an attacker cannot deterministically predict the preamble that will be used for future packet transmissions. This operation may make it difficult for an attacker to transmit a jamming signal that incorporates the correct preamble, thereby reducing the probability of success of such an attack.

[0073] In a UWB system, each participating UWB node device (e.g. Figure 1 One or more of the positioning devices 102 or anchor points 104 of the embodiment of the present invention includes a secure deterministic pseudo-random number generator (PRNG) that generates numbers based on an initial seed value (e.g., a cryptographic PRNG). The output of such a PRNG is used for the desired pseudo-random selection of the network preamble.

[0074] To properly configure the devices (e.g., establish a shared initial seed value for the devices' PRNG), configuration data for the participating devices is exchanged over a secure and non-intrusive out-of-band network. Additional data, such as the current preamble hopping state, may also be transmitted over this channel.

[0075] Figure 2 An apparatus 150 (eg, Figure 1 The device 150 includes a memory 152 (e.g., a temporary storage memory or a permanent storage memory) configured to store configuration parameters for participating in the UWB network. As described herein, the parameters may include shared seed data that enables a processor 158 of the device 150 to determine an index of a preamble to be used for the next communication to occur in the UWB network. In an embodiment, the device 150 is configured to receive the network configuration parameters via an out-of-band communication channel using an out-of-band communication system 154. The out-of-band communication system 154 may include a radio controller configured to communicate using a non-UWB communication channel with a network controller configured to provide those network parameters.

[0076] In one embodiment, the parameters stored in the memory 152 further enable the processor 158 of the device 150 to configure the PRNG 156 to generate a predictable (but random) set of index numbers that the device 150 can use to determine the current preamble being used by the network, as described herein. The processor 158 can then use the corresponding preamble (e.g., the preamble retrieved from the memory 152) when processing communications transmitted or received by the UWB communication system 160.

[0077] In a UWB communication system, there are sufficient unused preambles with low cross-correlation at all times to achieve a desired level of resilience against preamble repetition interference. Typically, the number of unused codes will be determined by the applicable communication standard and the number and configuration of coexisting and overlapping individual UWB networks. In some embodiments, it may be the case that coexistence of UWB networks using the same set of preambles can be achieved. In this case, by pseudo-randomly hopping the preambles, collisions are less likely to occur if the set of preambles is large enough. Therefore, according to the present disclosure, multiple networks using the same set of preambles can operate near each other with a lower probability of interference.

[0078] In a specific example of the current system and method, the UWB system is configured to perform a downlink time difference of arrival (DL-TDoA) positioning protocol. In this protocol, a fixed number of pre-installed nodes (commonly referred to as anchor points (e.g., Figure 1Anchor point 104)) to an unknown number of mobile devices or tags (e.g., Figure 1 The positioning device 102 provides positioning support for the mobile node.

[0079] In the protocol, after an initial configuration / setup phase, each node periodically transmits the following sequence of messages based on a schedule: 1) the initiator node sends a ranging initiation message (RIM); 2) the responder nodes receive the RIM messages and reply in sequence with ranging response messages (RRM); and 3) the initiator device optionally sends a ranging final message (RFM).

[0080] Within the network, a mobile node listens to all transmitted messages and uses the received information together with the measured receive (RX) timestamp to locate itself. To schedule the transmission of messages, time is divided into units of blocks, rounds, and slots. For illustration, Figure 3 A breakdown of a timeline depicting UWB communications broken down into blocks, rounds, and time slots. Specifically, timeline 200 shows two ranging blocks 202 and 204. Each ranging block is broken down into a number of ranging rounds 206 and 208. Additionally, each round 206, 208 is broken down or subdivided into a number of smaller time slots 210.

[0081] The ranging blocks 202, 204 are set to repeat periodically. Within the network, all participating nodes are configured with designated block 202, 204, round 206, 208 and time slot 210 durations to enable scheduling of message transmission and reception operations.

[0082] In a time slot 210, at least one message transmission or reception may typically be performed. In a typical configuration, a DL-TDoA ranging round contains at least as many time slots as anchor devices to allow for undisturbed transmission of all involved messages. This enables the transmission of an initial RIM packet, a responsive RRM message packet, and a final RFM packet for each ranging round 206. The data packets transmitted in each time slot 210 may be encoded in a variety of different formats according to various standards and protocols. Figure 3 Within, for example, the time slot transmission may be encoded according to any of the formats 212a, 212b, 212c, and 212d. As depicted, each packet encoding may include a payload (e.g., PHY PAYLOAD), which may appear at a different location in each packet. However, all packets 212 are similar in that they each begin with a synchronization header (SYNC) that includes a preamble sequence and an SFD. The present disclosure relates to carefully selecting a preamble for constructing the SYNC portion of a UWB data packet.

[0083] The SYNC portion of the packet contains N repetitions of an extended preamble standardized according to an applicable communication standard. The preamble specifies a sequence of positive UWB pulses, negative UWB pulses, or no UWB pulses to be transmitted. The SYNC field contains N repetitions of an extended code sequence, for example, a 32-symbol preamble or a SYNC field includes an extended preamble repeated 32 times. After the SYNC portion, a frame start delimiter (SFD) is included, which delimits the beginning of the packet after the synchronization header (SHR). Subsequently, the packet may optionally include an STS sequence, which contains a pseudo-random pulse sequence for secure ranging. The PHR block is a PHY header and indicates some properties of the signal and the length of the PSDU. Finally, in the PSDU, a MAC header and the rest of the payload are included, for example, some additional data.

[0084] When configuring transmissions in a particular time slot 210 to use a particular preamble, the available preamble space may be defined as P, where N P Indicates the number of available preambles:

[0085]

[0086] Value N 轮次 Defined as the number of ranging rounds within a ranging block. N Ranging Slots is defined as the number of time slots in a ranging round. The preamble hopping state s is a counter that is incremented after each time slot. The preamble hopping state s can be translated into the corresponding time slot index i according to the message scheduling mode. S , ranging round index i R and ranging block index i B :

[0087] i S =s mod N 测距时隙 (2)

[0088]

[0089] Nodes participating in the network are aware (due to the initial network setup / configuration step (e.g., via Figure 2 The out-of-band communication system 154 of the device 150 occurs)) value N 轮次 and N 测距时隙 Therefore, the node can determine the (i S ,i R ,i B ) tuple. Therefore, the node can use the tuple to determine the preamble jump state s for the next transmission according to the following expression:

[0090] s(i S ,i R ,iB )=i S +i R ·N 测距时隙 +i B ·N 轮次 ·N 测距时隙 (5)

[0091] Knowing the preamble hopping state s for the next transmission, the node can derive the corresponding preamble selector p. 索引 Indicates that a random number is generated from a pseudo-random number generator (PRNG) at the calling index (for example, Figure 2 The integer extracted by PRNG 156 is as follows.

[0092]

[0093] Having determined these values, the node can determine the preamble to be used for the next transmission as

[0094] As described above, the output of the PRNG is split so that each time slot is assigned its own pseudo-random preamble. All devices participating in the UWB network (e.g., Figure 2 The devices 150 of the network have similarly configured PRNGs, so that for a particular preamble hopping state s as input, the PRNG of each device generates the same output indicating the same preamble. Therefore, assuming that the various devices participating in the network know the same preamble hopping state s, the devices can simultaneously identify the same preamble, thereby achieving successful communication via the network.

[0095] It should be noted that extracting a specific S ,i R ,i B ) tuple's preamble can be efficient using a PRNG that allows the internal state of the generator to be easily modified. In such a case, the state information can be shared with all network participants (e.g., via an out-of-band communication channel) to ensure that the PRNGs of all devices are configured to generate the same output given a particular input value. An example of such a PRNG is the AES-based PRNG described in the IEEE Std 802.15.4z-2020 standard (for STS generation) that meets this property.

[0096] To illustrate this method, Figure 4 3 is a flow chart depicting a method 300 for performing preamble selection according to the present disclosure. The method may be performed by one or more devices (eg, Figure 2 Device 150) is executed.

[0097] In an initial step 302 of method 300, after the device is appropriately configured to communicate with the network (e.g., via out-of-band transmission of various network and PRNG configuration parameters), the device is configured to determine a value for a current preamble hopping state s to align the device's PRNG (e.g., Figure 2 The PRNG 156) state is used for the next data transmission of the device.

[0098] In the case where a PRNG is configured, in step 304, a pseudo-random preamble is selected from the appropriately configured PRNG. The output is then reduced modulo |P| (see expression (6) above). This output value enables the device to determine the corresponding preamble. Thus, in step 306, a preamble may be generated based on the PRNG output (e.g., according to expression (6) above).

[0099] In this arrangement, the necessary shared PRNG seed value for realizing the PRNG can be exchanged via secure out-of-band network communication (e.g., via initial network setup or configuration) during the configuration of the participating device, or can be derived by the participating device from a shared secret supplied in other ways. In some cases, for example, the participating device receives the current preamble jump state s and the remaining configuration data during the initial setup and configuration. Knowing the shared seed, network scheduling parameters (e.g., the size and duration of each network block, round and time slot), the preamble set P and the preamble jump state s allows the device (e.g., mobile device) that joins the UWB system at any time to restore the valid PRNG state and quickly join the message exchange. Such devices are configured to add an offset to the received preamble jump state s to adapt to its required setup time until it can start receiving messages. Note that rotating the initial seed from time to time can further improve the security level provided. For example, this makes the time-consuming attack of leaking the initial seed impractical.

[0100] In a specific network, assuming that there are five available preambles (P0-P4), the DL-TDoA exchange (e.g., Figure 1 The corresponding pseudo-random preamble code sequence in the network shown in the figure may be as shown in Table 1 below.

[0101] Time slot 0 (RIM) P3,P0,P0,P4,P2,P0,P1,P2,P3,P3,… Time slot 1 (RRM1) P2,P0,P2,P4,P2,P2,P3,P3,P3,P1,… Time Slot 2 (RRM2) P4,P0,P0,P3,P1,P0,P4,P3,P1,P0,… Time slot 3 (RRM3) P2,P1,P0,P0,P0,P3,P2,P1,P0,P4,… Time slot 4 (RFM) P2,P1,P4,P1,P2,P0,P1,P4,P0,P3,…

[0102] Table 1

[0103] Therefore, the attacker can only guess which preamble might be used in the future, which reduces the probability of successfully jamming the transmission.

[0104] During network operation, a ranging round (during which ranging data is exchanged via wireless data transmission) begins with the receipt of an initial RIM message by all participating devices except its initiator (initiator). In the current embodiment, the current preamble hopping state s is added to or encoded into the RIM message to help resynchronize the preamble across all participating nodes. All nodes can use this received state s and compare the state s with the local state of the node to confirm whether the preamble generated by the node is still synchronized, and if not, the node can use the received state s to recover a valid PRNG state.

[0105] In the event that a node fails to receive a valid RIM message and a particular ranging round times out, whether due to interference or poor channel conditions (e.g., obstacles, noise, ...), the node may need to extract a set of preambles to be used in future rounds of transmission. The present disclosure provides a method for performing preamble resynchronization of each device according to the state of the affected device (e.g., whether it is synchronized with the transmission schedule).

[0106] Specifically, when a device is synchronized with a transmission schedule of a particular network, but the device has not received a recent RIM transmission encoding a preamble jump state s value, a method is proposed that uses an in-band message to enable the device's PRNG to remain synchronized, and utilizes the fact that the affected device is still synchronized with the transmission schedule to determine the upcoming message preamble value. Specifically, if RIM reception times out within a particular round, there may be enough time to extract the preamble of the next round and set up the receiving device again (i.e., by configuring the node's PRNG). Then, if the next round also times out and RIM reception fails (e.g., due to poor channel conditions or advanced attackers), this process can continue until all unique preambles are tried once, or a retry threshold is exceeded. These conditions indicate severe state deviations, poor channel conditions, or attackers that interfere with all or nearly all preambles. Alternatively or in addition, the last successful RIM reception may be old enough that the time-based schedule cannot be maintained due to clock synchronization problems. In any of these cases, the device then falls back to a method that enables the device to perform resynchronization without receiving (or recently receiving) RIMs.

[0107] In this case, the device selects a preamble and waits for a period of time to successfully receive a message to synchronize the preamble. How to select this preamble depends on the capabilities of the UWB network, specifically, whether an undisturbed, secure out-of-band communication channel is available.

[0108] If such an undisturbed, secure out-of-band communication channel is available, the channel can be used to periodically broadcast the current preamble hopping state s or send the preamble hopping state s upon request of the device. The device can then use this state to determine the preamble that should be used for RIM transmission in the near future. The affected device then performs a timed wait for this message. If reception times out, the device can use the preamble hopping state s again to determine a different preamble to use in the near future, as the previous preamble may have been interfered with. If there are no options for untried preambles in the near future, the least recently used near future preamble can be retried. If all unique preambles have been tried, the state is reset and the process starts over.

[0109] As an in-band extension or alternative, in case no such out-of-band channel is available, the node may be configured to wait to receive a subsequent RIM, but may also utilize unused time slots in the schedule to introduce additional dedicated ranging synchronization messages (RSMs).

[0110] The pseudo-random selection of preambles may have disadvantages, since the time until a certain preamble is transmitted is probabilistic. Therefore, the time required for preamble resynchronization is also probabilistic. For this reason, a dedicated synchronization message may incorporate the current preamble hopping state s and may be used directly for preamble resynchronization between participating nodes.

[0111] Different schemes can be used to select the preamble for RSM transmission. In the first scheme, the initiator transmits the RSM using a preconfigured preamble, which allows new nodes to quickly join the UWB network in the absence of interfering devices. In the second scheme, the initiator transmits the RSM and the preamble in a sequence consisting of a pseudo-randomly selected permutation of the preamble space. The advantage of this approach is that all unique preambles are used periodically in a sequence, just in a different order. Therefore, this type of RSM transmission can result in deterministic resynchronization time (i.e., a node waiting for 2·|P| transmissions of the RSM should see each preamble at least once). The required pseudo-random permutation can be efficiently generated on the fly using algorithms such as the Fisher-Yates shuffle.

[0112] In various embodiments, the UWB network can be configured to communicate with each other in different time slots (e.g., Figure 3 Both schemes are used by transmitting the generated RSM in the time slot 210 of the UE. A node performing resynchronization in such a network first selects a preconfigured preamble (if available) and then waits for RIM or RSM reception until a timeout. If a timeout occurs, the node pseudo-randomly selects a preamble and waits for reception again. In situations involving further timeouts, this process can be repeated until a message is received and preamble resynchronization can be performed.

[0113] Once successful, the preamble generation process described above for synchronization nodes is first attempted for the next failed RIM reception. In this method, the node may decide to stop or pause this method after a certain number of failed attempts for energy saving. RSM using a fixed preamble can be implemented by adding the preamble hopping state s to the existing pre-polling message (RCM) in the existing two-way ranging protocol. For example, for the DL-TDoA protocol, a similar pre-RIM data message can be added before the RIM transmission.

[0114] Typically, all participating nodes, except the initiator (since the initiator is responsible for transmitting RIM and RSM messages and is therefore responsible for determining the current preamble hopping state), may use the preamble generation process for out-of-sync nodes until they receive at least one valid RIM.

[0115] Figure 5 is a device (e.g., Figure 2 Flow chart of a method 400 for determining a current preamble hopping state required for future communication during a communication time slot by a device 150) of the present invention. The method 400 is implemented by a participating device, such as Figure 1 Anchor point 104 or device 102 or Figure 2 One or more of the devices 150.

[0116] In step 402, the device determines whether the device is currently synchronized with the UWB network so that a time-based determination of an upcoming preamble is possible. This may involve the device determining whether the device has recently successfully communicated with the network (indicating that the device is time synchronized) or whether the device has not successfully communicated with the network for an extended period of time (indicating that the device is not time synchronized).

[0117] If the devices are time synchronized, the devices may be able to algorithmically determine the preamble of the upcoming time slot. Therefore, in step 404, the devices determine to make the next message in the next RIM communication time slot (e.g., Figure 3 The device may determine the preamble that appears in the upcoming time slot 210). This may involve, for example, the device independently setting the preamble hopping state s to a value associated with the particular upcoming time slot. Based on the preamble hopping state s, the device may then operate the device's PRNG to determine the preamble associated with the preamble hopping state s. In step 406, where the preamble is determined, the device waits for reception of a RIM message, and in step 408, determines whether the received RIM message is successfully received and decoded using the preamble as determined in step 404. If the RIM message is successfully received and decoded, the method continues to step 410 and the preamble hopping state s determined based on the received RIM message is returned.

[0118] However, if a RIM message is not successfully received in step 408, the method proceeds to step 412, where the device determines whether a time-based schedule can be performed in which the device attempts to determine the preamble of the upcoming RIM transmission. If this is not possible (e.g., the device lost time synchronization with the network while performing steps 404, 406, and 408), the method proceeds to step 416, where the device performs an alternative method for determining a preamble that does not require the device to synchronize time with the network.

[0119] If time-based scheduling is possible (step 412) and the retry threshold has not been exceeded (e.g., a predetermined number of times that the loop including steps 404, 406, 408, 412, and 414 has been performed consecutively) (step 414), the method returns to step 404 and the device determines another preamble and again attempts to successfully receive the upcoming RIM message using the determined preamble.

[0120] Therefore, returning to step 402, if the device determines that time-based scheduling or determination of the preamble is not possible, the method proceeds to step 416, in which the device determines whether it has previously received the preamble hopping state s (e.g., via an out-of-band communication channel). If not, and the device is unaware of the current preamble hopping state, then in step 418, the device selects a preamble that is pseudo-randomly determined or is a predetermined fixed value. In this case, it may be necessary for the device to select a preamble and then wait (possibly for a significant amount of time) until the device receives a transmission that is successfully decoded using the selected preamble. At this point, the device can resynchronize with the network.

[0121] In this step 418, a pseudo-random or predetermined (i.e., fixed) preamble is selected. Some networks may be configured to periodically transmit resynchronization messages (e.g., RSMs) that facilitate rapid resynchronization of the device with the network (e.g., one RSM every N blocks). In this case, the RSMs may be encoded using a subset of the available preambles (i.e., from which the pseudo-random preambles are selected) such that the device must receive fewer RSMs before a pseudo-randomly selected preamble in the subset successfully decodes the RSM. Alternatively, the RSMs may be encoded such that all N preambles must be used before the preamble can be repeated. p In this case, in step 418, p A device that randomly selects a preamble from the available preambles will only need to wait (in the worst case) N seconds before guaranteeing that the RSM can successfully receive and decode using the selected preamble. p RSM. In this case, it may occupy "2*Np " RSM until resynchronization is complete. For example, if the following RSM preamble sequence is utilized (there are 4 preambles), the out-of-sync node waits for preamble P1 and starts listening shortly after the first transmission of P1 begins:

[0122] P1,P2,P3,P4,P2,P4,P3,P1 1 2 3 4 5 6 7 8

[0124] In this case, it will take 8 time steps (2*N p ) until resynchronization is complete. In another embodiment, different types of RSMs may be transmitted in different blocks. For example, two RSMs per N blocks may be transmitted, the first with a fixed preamble, facilitating fast resynchronization, and the second with a subset of available preambles, where resynchronization takes longer but provides greater resilience against interference.

[0125] However, if the device is aware of the current preamble hopping state, then in step 420, the device is configured to select a near future preamble based on the current preamble hopping state s. The near future preamble may be a preamble that the network may use when it appears later in a subsequent time slot, that is, in the next N (e.g., 10, 15 or more) time slots. The idea is that because the device is not time synchronized, the device cannot determine the preamble of the next 'next' time slot, because the time slot may have passed or may not actually occur for a period of time. Therefore, the device will select the preamble that the device predicts the network will use in the next N time slots (i.e., the "near future"). The device can then receive sequential network transmissions and use the preamble to attempt to decode each subsequent transmission. Ultimately, the transmission will be successfully decoded using the selected preamble.

[0126] Using the preamble determined in step 418 or step 420, the device waits for reception of a RIM (or RSM) message in step 422, and determines in step 424 whether the received RIM (or RSM) message is successfully received and decoded using the preamble as determined in step 418 or step 420. If the RIM (or RSM) message is successfully received, the method proceeds to step 410, and returns the preamble jump status s determined according to the received RIM (or RSM) message.

[0127] However, if a RIM (or RSM) message is not successfully received in step 424, the method proceeds to step 426, in which the device determines whether it has received a preamble jump status s via out-of-band communication (e.g., whether the device has synchronized or successfully connected to the network). If not, the device selects a pseudo-random preamble in step 428, and if so, the device selects the least recently tried near-future preamble (i.e., a preamble different from the preamble previously selected in step 420) in step 430. In the event that a preamble is selected in step 428 or step 430, the method returns to step 424, and the device waits to receive and process a RIM (or RSM) message using a new preamble. The device continues to execute the control loop of steps 424, 426, and 428 or 430 until the device selects a preamble message that enables the device to successfully receive and decode a RIM (or RSM) message (e.g., in any of steps 418, 420, 428 and / or 430), wherein the RIM (or RSM) message indicates that the device is now synchronized and configured for continued communication with the network.

[0128] Figure 6 5 is a flow chart depicting a method 500 that may be implemented by a device participating in a UWB network according to the present disclosure. In an initial step 502, a device (e.g., Figure 2 The device 150 is configured to determine the preamble to be used in the next network communication time slot. As described above, this can be performed by providing the current preamble jump state s as an input to the PRNG (i.e., the preamble jump state s is equal to the input data value to the PRNG). The output of the PRNG is then mapped to a specific preamble index associated with the specific preamble. In step 504, the device is configured to use the preamble previously determined in step 502 to process the communication occurring in the next communication time slot. If the message received in the time slot is successfully received and decoded using the selected preamble, the method moves to step 506, in which the device is configured to increment the preamble jump state s and return to step 502 to determine the preamble for the next time slot. However, if the message is not successfully received, the method moves to 508, in which the device is configured to resynchronize the preamble jump state s. This step can be performed, for example, by the device Figure 5 The method 400 is implemented as described above.

[0129] In some embodiments of the present systems and methods, computational overhead may be reduced to some extent by performing a preamble selection routine in which only the preamble selection routine is used in each ranging round (e.g., Figure 2 ranging rounds 206, 208) instead of every time slot (e.g., Figure 1time slot 210) to change the preamble code.

[0130] In some UWB network implementations, an attacker who knows the syntax and timing of the preamble selection protocol may be able to construct packets that can be injected into network communications from time to time due to the limited entropy of the network's preamble space. In such cases, it may be necessary to cryptographically protect the packets exchanged to detect active jammers and mitigate the injection of carefully designed preamble jump state values ​​that may reduce the availability of the system even with the application of the present invention.

[0131] The current preamble selection method can be incorporated into other communication networks / protocols that use preambles (e.g., existing code division multiple access (CDMA) schemes) to increase channel throughput and coexistence between different co-located UWB networks. Exploiting low cross-correlation between pseudo-random preambles of different time slots can allow multiple UWB networks using the same set of preambles to coexist. Some embodiments involve tracking preambles used in active communication jamming attacks and excluding those preambles from the preamble selection process if the remaining entropy in the remaining preambles is still high enough to avoid positioning round failures and increase real-time guarantees.

[0132] As will be appreciated by those skilled in the art, aspects of the present disclosure may be embodied as systems, processes, methods, and / or program products. Figure 1 The positioning device 102 or anchor point 104) can take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, microcode, etc.), or an embodiment combining software and hardware aspects, which may generally be referred to herein as a "circuit", "circuitry", "module" or "system". In addition, aspects of the present disclosure may take the form of a program product embodied in one or more computer-readable storage media, wherein the one or more computer-readable storage media have computer-readable program code embodied thereon. (However, any combination of one or more computer-readable media may be utilized. The computer-readable medium may be a computer-readable signal medium or a computer-readable storage medium.)

[0133] A computer-readable storage medium may be, for example, (but not limited to), an electronic, magnetic, optical, electromagnetic, infrared, biological, atomic, or semiconductor system, device, controller, or apparatus, or any suitable combination of the foregoing, wherein the computer-readable storage medium itself is not a transient signal. More specific examples of computer-readable storage media (a non-exhaustive list) may include the following: an electrical connection with one or more wires, a portable computer disk, a hard disk, a random access memory ("RAM"), a read-only memory ("ROM"), an erasable programmable read-only memory ("EPROM" or flash memory), an optical fiber, a portable compact disc read-only memory ("CD-ROM"), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this article, a computer-readable storage medium may be any tangible medium that can contain or store a program used by or in conjunction with an instruction execution system, device, controller, or apparatus. The program code embodied on a computer-readable signal medium may be transmitted using any appropriate medium, including but not limited to wireless, wired, optical fiber cable, RF, etc., or any suitable combination of the foregoing.

[0134] A computer readable signal medium may include a propagated data signal having computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such propagated signals may take any of a variety of forms, including but not limited to electromagnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in conjunction with an instruction execution system, device, controller, or apparatus.

[0135] The block diagram in the accompanying drawings shows the architecture, functionality and operation of the possible implementation scheme of the circuit system, system, method, process and program product according to each embodiment of the present disclosure. In this regard, some boxes in the block diagram can represent the module, segment or part of the code, which includes one or more executable program instructions for implementing the specified logical function. It should also be noted that in some embodiments, the function marked in the box may not occur in the order marked in the figure. For example, the two boxes shown in succession can actually be performed substantially simultaneously, or these boxes can sometimes be performed in reverse order, depending on the functionality involved.

[0136] The module implemented in software for various types of processors to perform may, for example, include one or more physical or logical blocks of computer instructions, which may, for example, be organized as an object, a process or a function. However, the executable file of the identified module need not be physically located together, but may include very different instructions stored in different locations, including modules when these instructions are logically joined together, and realize the stated purposes of the module. In fact, the module of the executable code may be a single instruction or many instructions, and may even be distributed on several different code segments, between different programs, and distributed across several memory devices. Similarly, operational data (e.g., the knowledge base of the weights and / or deviations of the adaptation described herein) may be identified and shown in this article module, and may be embodied in any suitable form and organized in any suitable type of data structure. Operational data may be collected as a single data set, or may be distributed in different locations, including being distributed on different storage devices. Data may provide electronic signals on a system or network.

[0137] These program instructions may be provided to one or more processors and / or controllers of a general-purpose computer, a special-purpose computer, or other programmable data processing device (e.g., a controller) to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device create a circuit system or component for implementing the functions / actions specified in the block diagram.

[0138] It should also be noted that each block of the block diagram and the combination of blocks in the block diagram can be implemented by a dedicated hardware-based system (e.g., which may include one or more graphics processing units) or a combination of dedicated hardware and computer instructions that performs the specified function or action. For example, a module can be implemented as a hardware circuit, including custom VLSI circuits or gate arrays, off-the-shelf semiconductors (e.g., logic chips, transistors, controllers, or other discrete components. A module can also be implemented in a programmable hardware device, such as a field programmable gate array, programmable array logic, a programmable logic device, a dedicated IC, a microcontroller, a system on a chip, a general-purpose processor, a microprocessor, etc.

[0139] Computer program code (i.e., instructions) for carrying out operations of various aspects of the present disclosure may be written in any combination of one or more programming languages, including object oriented programming languages ​​such as Java, Smalltalk, Python, C++, conventional procedural programming languages ​​such as the "C" programming language or similar programming languages, or any machine learning software disclosed herein.

[0140] These program instructions may also be stored in a computer-readable storage medium, which may direct a computer system, other programmable data processing device, controller or other apparatus to function in a specific manner so that the instructions stored in the computer-readable medium produce an article of manufacture, which includes instructions for implementing the functions / actions specified in the block diagram.

[0141] The program instructions may also be loaded onto a computer, other programmable data processing device, controller or other apparatus so that a series of operating steps are performed on the computer, other programmable device or other apparatus to produce a computer-implemented process, so that the instructions executed on the computer, other programmable device or other apparatus provide a process for implementing the functions / actions specified in the block diagram.

[0142] The preceding detailed description is merely illustrative in nature and is not intended to limit the embodiments of the subject matter or the application and uses of such embodiments.

[0143] As used herein, the word "exemplary" means "serving as an example, instance, or illustration." Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background or detailed description.

[0144] The connecting lines shown in the various figures contained herein are intended to represent exemplary functional relationships and / or physical couplings between the various elements. It should be noted that many alternative or additional functional relationships or physical connections may be present in the embodiments of the subject matter. In addition, certain terms may also be used herein for reference purposes only, and therefore do not wish to be restrictive, and unless the context clearly indicates, the terms "first", "second" and other such numerical terms referring to structures do not imply a sequence or order.

[0145] As used herein, "node" means any internal or external reference point, connection point, junction, signal line, conductive element, etc., at which a given signal, logic level, voltage, data pattern, current or quantity exists. In addition, two or more nodes may be implemented by one physical element (and although received or output at a common node, two or more signals may still be multiplexed, modulated or otherwise distinguished).

[0146] The above description refers to elements or nodes or features being "connected" or "coupled" together. As used herein, unless otherwise expressly stated, "connected" means that one element is directly joined to (or directly communicated with) another element, and is not necessarily mechanically joined. Similarly, unless otherwise expressly stated, "coupled" means that one element is directly or indirectly joined to (or directly or indirectly electrically communicated with or otherwise communicated with) another element, and is not necessarily mechanically joined. Therefore, although the schematic diagrams shown in the accompanying drawings depict an exemplary arrangement of elements, additional intermediate elements, devices, features, or assemblies may be present in the embodiments of the depicted subject matter.

[0147] Although at least one exemplary embodiment has been presented in the above detailed description, it should be understood that there are a large number of variations. It should also be understood that one or more exemplary embodiments described herein are not intended to limit the scope, applicability, or configuration of the claimed subject matter in any way. In fact, the above detailed description will provide a convenient guide for implementing one or more of the described embodiments to those skilled in the art. It should be understood that various changes may be made to the function and arrangement of elements without departing from the scope defined by the claims, and the scope defined by the claims includes known equivalents and foreseeable equivalents at the time of filing this patent application.

Claims

1. A system, characterized in that: include: a plurality of ultra-wideband (UWB) anchor points configured to broadcast UWB timing data in a plurality of data packets, wherein each data packet is associated with a preamble; as well as Device, the device comprising: a first radio controller configured to communicate with the plurality of UWB anchor points using a first protocol, a pseudo-random number generator configured to generate a pseudo-random output value based on an input data value; and A processor configured to: providing the input data value to the pseudo-random number generator so that the pseudo-random number generator outputs the pseudo-random output value; Determine a preamble using the pseudo-random output value; processing a data packet received using the first radio controller and from a first UWB anchor point of the plurality of UWB anchor points using the preamble to generate a processed data packet; and The location of the device is determined using the processed data packets.

2. The system according to claim 1, characterized in that The apparatus includes a second radio controller configured to communicate using a second protocol, wherein the second protocol is not a UWB communication protocol.

3. The system according to claim 2, characterized in that The processor is configured to receive, using the second radio controller, a first configuration parameter, wherein the first configuration parameter indicates a mapping of a pseudo-random output value of the pseudo-random number generator to a preamble.

4. The system according to claim 3, characterized in that The processor is configured to receive, using the second radio controller, second configuration parameters, wherein the second configuration parameters determine a configuration of the pseudo-random number generator.

5. The system according to claim 1, characterized in that The processor is configured to determine a current preamble hopping state value, and the preamble hopping state value is equal to the input data value provided to the pseudo-random number generator.

6. The system according to claim 5, characterized in that The first protocol subdivides communication operations into a plurality of sequential time slots, and the processor is configured to increment the preamble hopping state value after each subsequent time slot occurs.

7. The system according to claim 1, characterized in that When the apparatus is not time synchronized with the plurality of UWB anchor points, the processor is configured to: Determining a first preamble from a plurality of preambles, wherein the plurality of preambles are determined according to the first protocol; Repeating the first preamble to attempt to decode ranging start messages or ranging synchronization messages received from the plurality of UWB anchor points; and After successfully decoding a first ranging start message or a ranging synchronization message using the first preamble, current preamble hopping state values ​​of the plurality of UWB anchor points are determined.

8. The system according to claim 7, characterized in that The first preamble code is determined pseudo-randomly.

9. A device, characterized in that: include: a first radio controller configured to communicate using a first protocol; a pseudo-random number generator configured to generate a pseudo-random output value based on an input data value; as well as A processor configured to: determining a preamble based on an output of the pseudo-random number generator; as well as A data packet received using the first radio controller is processed using the preamble to generate a processed data packet.

10. A method, characterized in that include: providing an input data value to a pseudo-random number generator so that the pseudo-random number generator outputs a pseudo-random output value; using the pseudo-random output value as an input to a pseudo-random number generator to determine a preamble; processing a data packet received using a first radio controller configured to communicate using a first communication protocol using the preamble to generate a processed data packet; as well as The location of the device is determined using the processed data packets.

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