System and method for selecting an ultra-wideband preamble based on environmental conditions

Abstract

An ultra-wideband (UWB) wireless communication system includes a first wireless transceiver, which outputs a data unit with a first preamble code, the first preamble code including data for performing a time-of-flight distance measurement; a second wireless transceiver, which replaces the first preamble code of the data unit with a second preamble code to provide a performance level required for the time-of-flight distance measurement between the first and second wireless transceivers corresponding to the environment in which the second wireless transceiver is used; and a communication link between the first and second wireless transceivers, which transmits the data unit with the first preamble code from the first wireless transceiver to the second wireless transceiver, transmits the second preamble code from the second wireless transceiver to the first wireless transceiver, and exchanges subsequent electronic communications between the first and second wireless transceivers using the second preamble code.

Description

Technical Field

[0001] The present disclosure relates generally to ultra-wideband (UWB) wireless communications, and more particularly to a UWB device, such as a transceiver, that processes a preamble sequence according to an environment in which the UWB device is used. Background Art

[0002] UWB technology is used in wireless applications due to its superior positioning accuracy and high data throughput compared to other wireless technologies. UWB devices typically output power over a bandwidth greater than 100 MHz to allow determination of the time of flight (ToF) or related signal strength measurement to accurately estimate the distance between the transmitter and receiver.

[0003] The time of flight estimates generated by UWB devices are greatly affected by the presence of ambient noise, for example caused by reflective or damping materials in the environment, and sources of error that lead to UWB range measurements include non-line of sight, clock drift and interference, as well as inaccurate estimates that lead to ToF calculations. In particular, devices that are part of an IEEE 802.15.4 system typically transmit 500MHz or 1GHz pulses between, for example, a user device and a UWB base unit, which are grouped by symbols in data units such as packets, frames, etc. Typically, a preamble at the beginning of each data packet is transmitted to the receiver along with the relevant data to synchronize the transmitter and receiver to generate ToF data. The receiving device correlates the received symbols with a predetermined preamble sequence and generates a channel impulse response (CIR) indicating when the preamble sequence is received. A first path detection process or the like uses this information to estimate the time of flight.

[0004] IEEE 802.15.4 configurations are typically constructed and arranged to support different types of UWB preambles, which may vary in pulse repetition frequency, employ various sample sizes such as ternary or binary, use known or random symbols or other series of pulses, etc., as appropriate for the application. Summary of the invention

[0005] According to a first aspect of the present invention, there is provided an ultra-wideband (UWB) wireless communication system, comprising:

[0006] a first wireless transceiver that outputs a data unit having a first preamble, the first preamble including data for performing a time-of-flight distance measurement;

[0007] a second wireless transceiver that replaces the first preamble of the data unit with a second preamble to provide a performance level required for the time-of-flight distance measurement between the first and second wireless transceivers corresponding to an environment in which the second wireless transceiver is used; and

[0008] a communication link between the first and second wireless transceivers, the communication link transmitting the data unit with the first preamble from the first wireless transceiver to the second wireless transceiver, transmitting the second preamble from the second wireless transceiver to the first wireless transceiver, and exchanging subsequent electronic communications between the first and second wireless transceivers using the second preamble.

[0009] According to one or more embodiments, the communication link transmits the data unit in an ultra-wideband signal formatted to include a plurality of symbols at a predetermined number of bits per second in accordance with the IEEE 802.15.4 standard.

[0010] In accordance with one or more embodiments, the second wireless transceiver correlates the received symbols with a predetermined preamble sequence and generates a channel impulse response (CIR) indicating when the preamble sequence is received.

[0011] According to one or more embodiments, the UWB wireless communication system additionally includes a dedicated hardware processor that performs a first path detection process to process the CIR or the like to estimate the time-of-flight distance measurement.

[0012] According to one or more embodiments, the second wireless transceiver includes:

[0013] a correlator module that receives and demodulates the ultra-wideband signal from the communication link and correlates each received UWB symbol with a known sequence;

[0014] a channel impulse response (CIR) processor, the CIR processor generating a CIR based on a correlation result of each UWB symbol with the known sequence; and

[0015] A detection algorithm processor processes the CIR and compares the time of initial transmission of the data unit to a time of arrival to estimate the time-of-flight distance measurement.

[0016] According to one or more embodiments, the UWB wireless communication system additionally includes an energy estimator processor that provides a reference signal for tuning a UWB pulse template to the UWB symbol.

[0017] According to one or more embodiments, the UWB wireless communication system further includes a preamble selector, which selects the second preamble through the CIR processor, and the CIR processor performs a CIR analysis process to synchronize the transmitter of the first wireless transceiver with the receiver of the second wireless transceiver to generate data required to estimate the time-of-flight distance measurement.

[0018] According to one or more embodiments, the UWB wireless communication system further includes a preamble selector that selects the second preamble in response to the second wireless transceiver activating a sensor to detect the environment.

[0019] According to a second aspect of the present invention, there is provided an ultra-wideband (UWB) wireless transceiver, comprising:

[0020] an antenna that detects and quantizes UWB signals;

[0021] a detection algorithm processor that processes data units of the ultra-wideband signal to calculate a time of arrival of the signal; and

[0022] A preamble selector selects a preamble for the data unit such that the calculated arrival time accounts for the environment in which the wireless transceiver is used.

[0023] According to one or more embodiments, the antenna may receive the signal as a set of UWB pulses within one or more frequency bands of the UWB signal, and wherein the UWB wireless transceiver further includes a correlator module that generates a pulse that matches one of the set of UWB pulses in frequency and phase to perform a pulse pair correlation function.

[0024] According to one or more embodiments, the UWB wireless transceiver additionally includes an energy estimator processor that provides a reference signal for tuning a template including the UWB pulse to the UWB symbol.

[0025] According to one or more embodiments, the UWB wireless transceiver further includes a dedicated hardware processor that performs a first path detection process using the pulse pair correlation function to process a channel impulse response (CIR) indicating the time at which the data unit was received, which is in turn processed to estimate a time-of-flight distance measurement.

[0026] In accordance with one or more embodiments, the preamble selector selects the preamble to reduce errors associated with range-related measurements.

[0027] According to one or more embodiments, the UWB wireless transceiver further includes a CIR processor that performs a CIR analysis process to synchronize the transmitter of the first wireless transceiver with the receiver of the second wireless transceiver, wherein the preamble selector selects the preamble in response to the CIR processor performing the CIR analysis to generate time-of-flight data required to estimate the time-of-flight distance measurement.

[0028] According to one or more embodiments, the preamble is selected in response to the transceiver activating a sensor to detect the environment.

[0029] According to a third aspect of the present invention, there is provided a method for determining a distance between a first ultra-wideband (UWB) device and a second UWB device, comprising:

[0030] receiving, by the second UWB device, a data unit including a first preamble, the content of the first preamble being susceptible to an environment of the second UWB device; and

[0031] The first preamble is replaced with a second preamble describing the environment in which the second UWB device is used.

[0032] According to one or more embodiments, the method further comprises:

[0033] transmitting the second preamble to the first UWB device via the second UWB;

[0034] as well as

[0035] Subsequent electronic communications are exchanged between the first and second UWB devices using the second preamble.

[0036] According to one or more embodiments, the method further comprises:

[0037] selecting the second preamble by a channel impulse response (CIR) processor performing a CIR analysis process; and

[0038] In response to the CIR analysis, a transmitter of the first UWB device and a receiver of the second UWB device are synchronized to generate data needed to estimate a time-of-flight range measurement including the second preamble.

[0039] According to one or more embodiments, the method further comprises:

[0040] The second preamble is selected in response to a priori detection of the environment.

[0041] According to one or more embodiments, the second preamble is an ipatov preamble or a random or secure preamble selected according to the environment of the second UWB device. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] The present invention is illustrated by way of example and not limitation in the accompanying figures, in which like reference numerals indicate similar elements. Elements in the figures are illustrated for simplicity and clarity and have not necessarily been drawn to scale.

[0043] Figure 1is a network diagram of an environment in which embodiments of the present disclosure may be practiced.

[0044] Figure 2 is a schematic diagram illustrating a process for selecting a UWB preamble according to specific environmental conditions according to an example embodiment of the present disclosure.

[0045] Figure 3 is a flow chart illustrating a method of selecting a preamble for transmission between UWB electronic devices according to an example embodiment of the present disclosure.

[0046] Figure 4 is a flowchart illustrating a method of selecting a preamble for transmission between UWB electronic devices according to another example embodiment of the present disclosure. DETAILED DESCRIPTION

[0047] In short, embodiments of the inventive concept include systems and methods for selecting a UWB preamble type based on the environment and context in which a particular UWB transceiver device is used. The preamble type may affect related parameters such as sensitivity, preamble injection resistance, and energy consumption of the transmitting or receiving device, which may affect the performance of ToF estimation. Therefore, due to the impact of the environment on the preamble, the preamble applied in a specific environment may hinder the quality of the timestamp received by the UWB receiving device. The system and method according to the inventive concept solve the above problems by allowing the selection of an ideal preamble with the best performance for a specific situation (i.e., environment, context, etc.). Unlike conventional approaches, the system and method do not depend on a specific environment, but select a preamble from a set of available preambles based on the environment, which can provide the performance level required for the time-of-flight distance measurement between two UWB devices corresponding to the environment in which the UWB device is used. Therefore, the time of arrival (ToA) estimate, which estimates the time it takes for a signal to propagate from a transmitter to a receiver or other time-related deviations caused by environmental conditions, can be reduced to improve tracking accuracy, such as UWB positioning accuracy.

[0048] Figure 1 is a network diagram of an environment in which embodiments of the present disclosure may be practiced. In some embodiments, Figure 1 Some or all of the devices in the environment shown conform to the IEEE 802.15.4 standard.As shown, two UWB wireless transceivers 102, 104 exchange data via one or more transmission channels 110, collectively referred to as communication links.

[0049] The first UWB wireless transceiver 102 may be part of a user wireless device as well as an omni-directional antenna and processor for transmitting data using a technique that causes radio energy to be spread over the UWB band with low power spectral density and allows high data throughput with high accuracy for positioning and imaging devices.

[0050] The second UWB wireless transceiver 104 is constructed and arranged to detect, demodulate and / or decode signals including data from the first UWB wireless transceiver 102 via an antenna 122. The antenna 122 can receive signals as a group of pulses within multiple narrower frequency bands of the multi-band UWB signal. In some embodiments, the first UWB wireless transceiver 102 and / or the second UWB wireless transceiver 104 include both a transmitter and a receiver and are electrically coupled to the antenna 122. Although a single antenna 122 is shown, the wireless device (the first UWB wireless transceiver 102 and / or the second UWB wireless transceiver 104) includes (not shown) multiple transmitters, multiple receivers, multiple transceivers and / or multiple antennas. The antenna 122 can communicate with a signal detector or the like that detects and quantifies the signal received by the transceiver 104, for example, energy level, power spectral density, etc. In some embodiments, the first wireless transceiver 102 and the second wireless transceiver 104 are each part of a wireless device that includes a processing unit 26 that controls the operation of the transceiver circuit system and an associated antenna 122, and a memory device for storing program code executed by the processing unit to perform the processing required to control the transceivers 102, 104.

[0051] In addition to the antenna 122, the second UWB wireless transceiver 104 includes a correlator module 124, a channel impulse response (CIR) processor 126, a detection algorithm processor 128, and a preamble selector 130. Some or all of these components may be part of the first UWB wireless transceiver 102 in order to receive communications from the second UWB wireless transceiver 104.

[0052] A well-known feature of UWB data exchange is that the transmission channel is used to output or otherwise exchange multiple electromagnetic energy pulses or symbols with the UWB device at a predetermined number of bits per second and at a high frequency that complies with the IEEE 802.15.4 standard, but is not limited thereto. Here, the first UWB wireless transceiver 102 can encode a predetermined number of bits into each pulse, which is in turn transmitted by the transmission channel 110. Of particular relevance is the transmission of the UWB preamble. The preamble symbol is obtained by periodically modulating the continuous pulse output according to the code length of the ternary preamble, which may be affected by a noisy environment or other external conditions.

[0053] The correlator module 124 receives and demodulates the ultra-wideband signal from the transmission channel 110 and correlates each received UWB symbol with a known code sequence, for example, including a ternary code established by the IEEE standard or the like, and the known code sequence is required for synchronization between the UWB devices 102, 104. In some embodiments, the correlator module 124 includes a plurality of parallel correlator devices, each receiving a sub-band of the output signal transmitted by the first UWB wireless transceiver 102. The correlator module 124 generates pulses that match the UWB pulses generated by the UWB transmitter 102 in frequency and phase, for example, to perform a pulse pair correlation function on the received signal pulses. The correlator module 124 may include mixers, amplifiers, bandpass and low-pass filters, etc., to correlate the incoming signal with a known code sequence established by the IEEE standard or the like, and then output the incoming signal to the CIR processor 126. For example, the results of the correlation operation performed on each UWB symbol are combined to generate a CIR. The CIR processor 126 communicates with the detection algorithm processor 128 to generate a CIR to estimate the time of receiving the signal. In some embodiments, the processor 128 includes a dedicated hardware processor that performs a first path detection process to process the CIR or the like so that the system estimates the time-of-flight distance measurement. The CIR processor 126 may include an energy estimator processor 127 that provides a reference signal for correlating with the incoming pulse for accurate tuning to the incoming UWB symbol. In some embodiments, the detection algorithm processor 128 may include the energy estimator processor 127.

[0054] In some embodiments, the detection algorithm processor 128 estimates the time when a signal from the initial UWB device 102 is received. Specifically, when the UWB device receives a message, the time of arrival (ToA) provided from the timestamp of the incoming signal is measured. The detection algorithm processor 128 operates to calculate the time of flight of the signal using the timestamp content of multiple messages. By comparing the time of the initial transmission to the ToA, the UWB transceiver 104 can determine the time of flight or other signal strength measurement.

[0055] The preamble selector 130 selects an appropriate preamble to replace the preamble of the received signal based on the environment and performs in an optimal manner for the specific environment. The preamble selector 130 communicates with the detection algorithm processor 128, which can provide the results of the CIR analysis, which can provide information about multiple reflections, signal power levels, noise-related data, or other environmental calculations. Additionally or alternatively, the detection algorithm processor 128 provides data for a predetermined environment, for example, known a priori, and this data is used by the preamble selector 130 to determine the preamble based on the known environment.

[0056] As described herein, the generation of the CIR and therefore the estimation of the timestamp calculation may be affected by the characteristics of the preamble. For example, a longer preamble length may depend on the transmission length or other transmission parameters. In another example, the presence of device movement may determine the use of a shorter preamble. Due to the additional amount of data in the message, a longer preamble (e.g., 1024 symbols) requires an increased sensitivity (e.g., -102 to -106 dBm), which may allow for more accurate timestamps. Because the distance between the UWB devices 102, 104 changes due to the movement of the receiving UWB device 104, a shorter preamble (e.g., 256 symbols) with a lower sensitivity (e.g., -92 to -94 dBm) may be preferred. However, a longer preamble length (e.g., a length sufficient to include 1024 symbols) may increase energy consumption because the device must be activated for a longer period of time compared to a shorter preamble length. The tradeoff is that the preamble length may also indicate an increased amount of correlated data generated from the large number of signals in the preamble that contribute to the CIR at the receiving device 104, which in turn may improve the sensitivity needed in a noisy environment. Other preambles may be shorter and inserted into the data stream for fast resynchronization. The second UWB radio 104 may receive preambles of any length or number of symbols. Thus, the tradeoff between preamble length and energy consumption may affect the ToF estimation calculation.

[0057] In another example, a random or secure preamble can be used for timestamp estimation. Here, the timestamp does not need to estimate the CIR generated from the ipatov preamble according to the IEEE 802.15.4 standard. Therefore, the number of related symbols in the random preamble is constant, while the ipatov symbol may be lost. For example, when in receive mode, the device can scan the preamble in the air, during which the initial part of the preamble may be lost. The number of lost symbols can vary according to link budget and sensitivity and / or other factors. The CIR processor 126 can operate on the cumulative correlation of the repeated symbols of the ipatov preamble sequence, which is necessary for synchronization. In some embodiments, a random sequence preamble may exist. The feature of the random preamble is to increase security for preamble injection attacks or the like. On the other hand, the ipatov symbol provides a desirable autocorrelation property. Therefore, in view of the advantages and disadvantages of each preamble type, the preamble selector 130 can select the ipatov preamble or the random or secure preamble according to the environment.

[0058] In another example, the parameters may include a pulse repetition frequency (PRF). The frame preamble needs to be adapted to the configured transmission parameters, such as PRF. A higher PRF may produce a signal with more information that can be used for correlation. However, the additional pulses of the higher PRF may result in pulses that are close to each other, resulting in the generation of self-correcting side lobes or the like, thereby reducing the possibility of distinguishing between two different signal paths that are close, which may affect the accuracy and CIR of the correlation.

[0059] In other examples, the pulse shape may be affected by environmental factors such as antenna characteristics, reflections, the materials the signal travels through, and so on.

[0060] The examples herein illustrate how the generation of the CIR, and thus the estimation of the timestamp, may be affected by the characteristics of the preamble, but are not limited thereto. Figure 2 Systems and methods for optimizing preambles based on the context in which a UWB device is used are shown. Figure 3 and 4 As shown, different techniques for detecting the environment can be implemented, for example, analyzing CIR ( Figure 3 ) or determine the environment statically or a priori ( Figure 4 ).

[0061] Figure 2 is a schematic diagram illustrating a process for selecting a UWB preamble according to specific environmental conditions according to an example embodiment of the present disclosure.

[0062] The data flow 202 occurs via a transmission channel formed between the first UWB wireless transceiver 102 and / or the second UWB wireless transceiver 104. The transmission channel exchanges multi-symbol packets. Each transmitted packet 30 includes a preamble 32 and a multi-symbol data payload 34. For example, the preamble 32 may include, but is not limited to, a synchronization portion for providing packet detection, timing data, or the like. As described herein, Figure 1 The second UWB wireless transceiver 104 described in the specification can change the characteristics of the content of the preamble portion 32 of the packet 3 according to the environment and provide a trade-off between security, time-of-flight accuracy and energy consumption in different applications of a system including the transceivers 102, 104.

[0063] In view of the foregoing, the second UWB wireless transceiver 104 is in an ambient environment 16, which may include a context in which the UWB device 104 is used. For example, the ambient environment 16 may include a building, a car, or other enclosed environmental element where dense multipath signal exchanges may occur, or may include an open area outside a building where few such reflections are expected. Thus, the environmental conditions 204 apply to the presence of reflective materials that affect the preamble type with respect to sensitivity, energy consumption, distinguishing reflections that are close in time to the first path, etc.

[0064] A set of preambles 205 may be stored in a database or related storage device. The database may include a table, matrix, or the like populated with records identifying preambles that are more preferred for specific environmental conditions and selected based on the environment. In response to the environment 16, an appropriate preamble is selected and output to the second UWB wireless transceiver 104 via a data flow path 206, wherein the preamble replaces the preamble sent by the first UWB wireless transceiver 102, wherein subsequent communications are exchanged via a data flow path 208 using a preamble from the set of preambles 205 stored in the database. Subsequent communications between the UWB devices 102, 104 are conducted using the new preamble.

[0065] Figure 3 is a flow chart illustrating a method 300 for selecting a preamble for transmission between UWB electronic devices 102, 104 according to an exemplary embodiment of the present disclosure. In describing the method 300, reference is made to Figure 1 and 2 .

[0066] At block 302, the UWB receiver of the second UWB wireless transceiver 104 receives a preamble from the UWB transmitter of the first UWB wireless transceiver 102. The preamble is used for signal detection, frame synchronization, and / or other functions, particularly for synchronizing the transmitter and receiver to generate time-of-flight data required for UWB communication.

[0067] At box 304, CIR analysis is performed to detect the environment so that an estimate of the timestamp affected by the characteristics of the preamble can be obtained. The CIR analysis can provide information about the number of reflections from objects in the environment, signal power, noise level, or the like to determine an appropriate preamble. An appropriate preamble is required to reduce errors associated with distance-related measurements caused by non-line of sight, clock drift, interference, etc. In some embodiments, after obtaining the CIR, key features are analyzed, such as but not limited to the number of peaks in the CIR, the energy of the CIR, the distance between two paths of a multipath configuration, the first path skew, kurtosis, etc. In some embodiments, a machine learning algorithm classifies the environment, and the system provides a decision on the most appropriate preamble for the environment.

[0068] Therefore, at block 306, a new preamble is selected. At block 308, the new preamble is output from the second UWB wireless transceiver 104 to the first transceiver 102. At block 310, subsequent electronic communications between the UWB transceivers 102, 104 are performed using the new preamble. In some embodiments, the UWB transceivers 102, 104 are synchronized in response to the CIR analysis to generate data required for estimating a time-of-flight distance measurement that includes the new preamble.

[0069] Figure 4 is a flowchart illustrating a method 400 for selecting a preamble for transmission between UWB electronic devices according to another example embodiment of the present disclosure. Figure 1 and 2 .

[0070] At block 402, a UWB receiver of the second UWB wireless transceiver 104 receives a preamble from a UWB transmitter of the first UWB wireless transceiver 102. Block 402 is similar to Figure 3 302, so for the sake of brevity, the details are not repeated.

[0071] At block 404, information about the environment in which the receiving UWB device 104 is provided is received and processed. Thus, the environment is detected in a static manner. Here, the environment is known a priori. This information can be used, for example, when tracking the UWB device using sensors or other electronic components of the device, the device communicating with an IoT sensor, etc. If the device is located outside a building, then reflections and diffractions from objects in the expected environment are minimal. However, when the device is located inside a building, reflections from obstacles present in the indoor environment can result in multipath fading, thereby reducing the positioning accuracy of the UWB system.

[0072] At block 406, a new preamble is selected in response to the processing of the environmental data. At block 408, the new preamble is output from the second UWB wireless transceiver 104 to the first transceiver 102. At block 410, subsequent electronic communications between the UWB transceivers 102, 104 are performed using the new preamble.

[0073] As will be appreciated, the disclosed embodiments include at least the following. In one embodiment, an ultra-wideband (UWB) wireless communication system includes a first wireless transceiver that outputs a data unit having a first preamble, the first preamble including data for performing a time-of-flight distance measurement; a second wireless transceiver that replaces the first preamble of the data unit with a second preamble to provide a required level of performance for time-of-flight distance measurements between the first and second wireless transceivers corresponding to an environment in which the second wireless transceiver is used; and a communication link between the first and second wireless transceivers that transmits the data unit having the first preamble from the first wireless transceiver to the second wireless transceiver, transmits the second preamble from the second wireless transceiver to the first wireless transceiver, and exchanges subsequent electronic communications between the first and second wireless transceivers using the second preamble.

[0074] An alternative embodiment of the UWB wireless communication system includes one of the following features or any combination thereof. The communication link transmits a data unit in an ultra-wideband signal, which is formatted to include multiple symbols at a predetermined number of bits per second in accordance with the IEEE802.15.4 standard. The second wireless transceiver correlates the received symbol with a predetermined preamble sequence and generates a channel impulse response (CIR) indicating when the preamble sequence is received. The UWB wireless communication system further includes a dedicated hardware processor that executes a first path detection algorithm to process the CIR or the like to estimate the time-of-flight distance measurement. The second wireless transceiver includes a correlator module that receives and demodulates the ultra-wideband signal from the communication link and correlates each received UWB symbol with a known sequence; a channel impulse response (CIR) processor that generates a CIR based on the correlation results of each UWB symbol with the known sequence; and a detection algorithm processor that processes the CIR and compares the time of original transmission of the data unit with the arrival time to estimate the time-of-flight distance measurement. The UWB wireless communication system further includes an energy estimator processor that provides a reference signal for tuning the UWB pulse template to the UWB symbol. The UWB wireless communication system further includes a preamble selector that selects the second preamble by a CIR processor that performs a CIR analysis process to synchronize a transmitter of the first wireless transceiver with a receiver of the second wireless transceiver to generate data required for estimating a time-of-flight distance measurement. The UWB wireless communication system further includes a preamble selector that selects the second preamble in response to the second wireless transceiver enabling a sensor to detect an environment.

[0075] In another embodiment, an ultra-wideband (UWB) wireless transceiver includes an antenna that detects and quantizes an ultra-wideband signal; a detection algorithm processor that processes data units of the ultra-wideband signal to calculate an arrival time of the signal; and a preamble selector that selects a preamble of the data unit so that the calculated arrival time accounts for an environment in which a second wireless transceiver is used.

[0076] An alternative embodiment of the UWB wireless transceiver includes one or any combination of the following features. The antenna receives a signal as a set of UWB pulses within one or more frequency bands of the UWB signal, and the UWB wireless transceiver further includes a correlator module that generates a pulse that matches one of the set of UWB pulses in frequency and phase to perform a pulse pair correlation function. The UWB wireless transceiver further includes an energy estimator processor that provides a reference signal for tuning a template including the UWB pulse to the UWB symbol. The UWB wireless transceiver further includes a dedicated hardware processor that performs a first path detection process using the pulse pair correlation function to process a channel impulse response (CIR) indicating the time at which the data unit is received, which is in turn processed to estimate a time-of-flight distance measurement. A preamble selector selects a preamble to reduce errors associated with distance-related measurements. The UWB wireless transceiver further includes a CIR processor that performs a CIR analysis process to synchronize a transmitter of the first wireless transceiver with a receiver of the second wireless transceiver, wherein a preamble selector selects a preamble in response to the CIR processor performing the CIR analysis to generate time-of-flight data required for estimating time-of-flight distance measurements. The preamble selector selects the preamble in response to the transceiver activating a sensor to detect an environment.

[0077] In another embodiment, a method for determining a distance between a first ultra-wideband (UWB) device and a second UWB device includes: receiving, by the second UWB device, a data unit including a first preamble, the content of the first preamble being susceptible to an environment of the second UWB device; and replacing the first preamble with a second preamble describing an environment in which the second UWB device is used.

[0078] Alternative embodiments of the method include one or any combination of the following features. The method further includes: transmitting a second preamble to the first UWB device via the second UWB; and exchanging subsequent electronic communications between the first and second UWB devices using the second preamble. The method further includes: selecting the second preamble by a channel impulse response (CIR) processor that performs a CIR analysis process; and synchronizing a transmitter of the first UWB device and a receiver of the second UWB device in response to the CIR analysis to generate data required to estimate a time-of-flight distance measurement including the second preamble. The method further includes: selecting the second preamble in response to a priori detection of the environment. The second preamble is an ipatov preamble or a random or secure preamble selected based on the environment of the second UWB device.

[0079] Although the present invention is described herein with reference to specific embodiments, various modifications and changes may be made without departing from the scope of the present invention as set forth in the appended claims. Therefore, the description and drawings should be regarded as illustrative rather than restrictive, and all such modifications are expected to be included within the scope of the present invention. It is not intended that any benefit, advantage, or solution to a problem described herein with respect to a specific embodiment be construed as a key, required, or essential feature or element of any or all claims.

[0080] Unless otherwise stated, terms such as "first" and "second" are used to arbitrarily distinguish between the elements such terms describe. Therefore, these terms are not necessarily intended to indicate temporal priority or other priority of such elements.

Claims

1. An ultra-wideband (UWB) wireless communication system, characterized in that: include: a first wireless transceiver that outputs a data unit having a first preamble, the first preamble including data for performing a time-of-flight distance measurement; a second wireless transceiver that replaces the first preamble of the data unit with a second preamble to provide a required performance level for the time-of-flight distance measurement between the first and second wireless transceivers corresponding to an environment in which the second wireless transceiver is used; The second wireless transceiver comprises: a correlator module that receives and demodulates an ultra-wideband signal from a communication link and correlates each received UWB symbol with a known sequence; a channel impulse response (CIR) processor, the CIR processor generating a CIR according to a correlation result between each UWB symbol and the known sequence; and a detection algorithm processor that processes the CIR and compares a time of initial transmission of the data unit to a time of arrival to estimate the time-of-flight distance measurement; The UWB wireless communication system additionally includes a preamble selector that selects the second preamble via the CIR processor that performs a CIR analysis process to synchronize a transmitter of the first wireless transceiver with a receiver of the second wireless transceiver to generate data required to estimate the time-of-flight distance measurement; and a communication link between the first and second wireless transceivers, the communication link transmitting the data unit with the first preamble from the first wireless transceiver to the second wireless transceiver, transmitting the second preamble from the second wireless transceiver to the first wireless transceiver, and exchanging subsequent electronic communications between the first and second wireless transceivers using the second preamble.

2. The ultra-wideband (UWB) wireless communication system according to claim 1, characterized in that: The communication link transmits the data unit in an ultra-wideband signal formatted to include a plurality of symbols at a predetermined number of bits per second in accordance with the IEEE 802.15.4 standard.

3. The ultra-wideband (UWB) wireless communication system according to claim 2, characterized in that: The second wireless transceiver correlates the received symbols with a predetermined preamble sequence and generates a channel impulse response (CIR) indicating when the preamble sequence is received.

4. The ultra-wideband (UWB) wireless communication system according to claim 3, characterized in that: Additionally included is a dedicated hardware processor that performs a first path detection process to process the CIR or the like to estimate the time-of-flight distance measurement.

5. The ultra-wideband (UWB) wireless communication system according to claim 1, characterized in that: Additionally included is an energy estimator processor that provides a reference signal for tuning a UWB pulse template to the UWB symbol.

6. The ultra-wideband (UWB) wireless communication system according to claim 1, characterized in that: Additionally included is a preamble selector that selects the second preamble in response to the second wireless transceiver activating a sensor to detect the environment.

7. An ultra-wideband (UWB) wireless transceiver, characterized in that: include: an antenna that detects and quantizes UWB signals; a detection algorithm processor that processes data units of the ultra-wideband signal to calculate a time of arrival of the signal; as well as a preamble selector that selects a preamble for the data unit such that the calculated arrival time accounts for an environment in which the wireless transceiver is used; as well as a CIR processor that performs a CIR analysis to synchronize a transmitter of the first wireless transceiver with a receiver of the second wireless transceiver, wherein the preamble selector selects the preamble in response to the CIR processor performing the CIR analysis to generate time-of-flight data required for estimating a time-of-flight distance measurement.

8. A method for determining a distance between a first ultra-wideband (UWB) device and a second UWB device, characterized in that: include: The first wireless transceiver outputs a data unit having a first preamble including data for performing a time-of-flight distance measurement; The second wireless transceiver replaces the first preamble of the data unit with a second preamble to provide a performance level required for the time-of-flight distance measurement between the first and second wireless transceivers corresponding to the environment in which the second wireless transceiver is used; wherein the second wireless transceiver further: Receive and demodulate an ultra-wideband signal from a communication link and correlate each received UWB symbol with a known sequence; Generate a CIR according to a correlation result between each UWB symbol and the known sequence; as well as processing the CIR and comparing the time of initial transmission of the data unit to a time of arrival to estimate the time-of-flight distance measurement; as well as a preamble selector selecting the second preamble via the CIR processor, the CIR processor performing a CIR analysis process to synchronize a transmitter of the first wireless transceiver with a receiver of the second wireless transceiver to generate data required to estimate the time-of-flight distance measurement, and sending a data packet from the first wireless transceiver to the second wireless transceiver, the data packet having a first preamble; sending a second preamble from the second wireless transceiver to the first wireless transceiver; Subsequent electronic communications between the first wireless transceiver and the second wireless transceiver are performed using the second preamble.

9. A method of operating an ultra-wideband (UWB) wireless transceiver, comprising: Detect and quantify UWB signals; Processing data packets of the UWB signal to calculate the arrival time of the UWB signal; selecting the preamble of the data packet so that the calculated arrival time accounts for the environment in which the wireless transceiver is used; performing a CIR analysis to synchronize a transmitter of the first wireless transceiver with a receiver of the second wireless transceiver; and The preamble is selected in response to the CIR analysis to generate time-of-flight data required to estimate a time-of-flight distance measurement.

Images