METHOD FOR DETECTING A CHANGE IN A TRANSMISSION CHANNEL SYSTEM, RADIO MODULE AND RADIO SYSTEM

Description

Description

[0001] The present invention relates to a method for detecting a change in a transmission channel system of a vehicle, a radio module and a radio system.

[0002] Ultra-wideband (UWB) is a radio technology in which a low-power signal is transmitted over a wide frequency range, resulting in essentially no interference in occupied frequency bands. The transmitted signal consists of individual pulses. Depending on the modulation method used, the amplitude, polarity, and position of the individual pulses can be varied.

[0003] In a vehicle, for example an automobile, a transmitting unit for transmitting a transmitted signal and a receiving unit for receiving a received signal based on the transmitted signal can be arranged, wherein a transmission channel for transmitting the transmitted signal is determined by the environment. A change in the environment can cause the transmission channel to change, wherein a change in the transmission channel can occur by detecting a change in the channel impulse response of the transmission channel over time. A change in the transmission channel can be caused, for example, by a person entering the vehicle. However, detecting a ("real") change in the transmission channel, for example caused by a physical change in the vehicle, represents a challenge, since technical components such as the transmitting unit and / or the receiving unit have technical tolerances orMay contain inaccuracies. These technical tolerances or inaccuracies can lead to a detection unit for detecting changes in the transmission channel system not detecting a "real" change in the transmission channel, but rather an "apparent" change in the transmission channel caused by technical tolerances or inaccuracies.

[0004] For example, sampling the transmitted signal and / or the received signal to determine a channel impulse response may be subject to sampling inaccuracies. Amplitude fluctuations may therefore occur due to non-identical sampling times for the transmitted signal and the received signal. This disadvantageously makes it difficult to detect a change in the channel impulse response, where the change in the channel impulse response is essentially based on a "real" change in the transmission channel and not merely on technical sampling inaccuracies.

[0005] The object of the present invention is to at least partially remedy the disadvantages described above. In particular, the object of the present invention is to provide a particularly simple and / or accurate and / or reliable method for detecting a ("real") change in a transmission channel system or at least one transmission channel of a transmission channel system. Furthermore, the object of the present invention is to provide a particularly simple and / or cost-effective and / or compact radio module or radio system for detecting a ("real") change in a transmission channel system.

[0006] US 2017 / 212210 A1 discloses a time-reversed positioning system for representing channel impulse responses of multiple received signals in coordinate positions. DE 10 2010 034191 A1 discloses a method for frequency-dependent Doppler shifting between at least one radio transmitter and at least one radio receiver.

[0007] The above object is achieved by a method for detecting a change in a transmission channel system having the features of claim 1 and a radio module having the features of claim 16, as well as a radio system having the features of claim 17. Further features and details of the invention emerge from the subclaims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the radio module according to the invention and / or the radio system according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0008] According to a first aspect, the present invention provides a method for detecting a change in a transmission channel system of a vehicle having at least one transmission channel. The method comprises, as one step, transmitting an ultra-wideband transmission signal by means of a transmitting unit over the transmission channel system, as a further step, receiving at least one received signal based on the ultra-wideband transmission signal by means of a receiving unit, and, as a further step, determining at least one channel impulse response of the at least one transmission channel of the vehicle based on the received signal by means of a determination unit. These aforementioned steps are repeated several times in order to determine at least a plurality of channel impulse responses of the at least one transmission channel.A further step of the method according to the invention is a respective adaptation of at least a portion of the determined channel impulse responses of the plurality of channel impulse responses of the at least one transmission channel to a known channel impulse response of the at least one transmission channel of the vehicle to form a respective adapted channel impulse response by means of an adaptation unit such that a correlation coefficient resulting from the determined channel impulse response and the known channel impulse response is increased. The method further comprises, as a further step, filtering at least a portion of the adapted channel impulse responses of at least the at least one transmission channel in a time direction by means of a filter unit to obtain a specific filter signal of the filtered, adapted channel impulse responses of the at least one transmission channel.In addition, the method according to the invention comprises, as a further step, detecting the change in the transmission channel system at least on the basis of the specific filter signal of the at least one transmission channel by means of a detection unit.

[0009] The process steps described above and below can, where technically feasible, be carried out individually, together, simply, multiple times, in parallel and / or consecutively in any order.

[0010] The vehicle is in particular a motor vehicle, preferably a passenger car or a lorry.

[0011] A change in the transmission channel system is to be understood, in particular, as a change in the transmission channel system over time. A change in the transmission channel system is, in particular, the detection of a change in at least one transmission channel of the transmission channel system. If the transmission channel system has multiple transmission channels, it is also conceivable that a change in the transmission channel system exists, in particular, if a change in the respective transmission channel has been detected for multiple transmission channels, preferably for all transmission channels. Thus, detection of a change in the transmission channel system can be particularly reliable.

[0012] Detecting a change in the vehicle's transmission channel system is particularly useful for monitoring the vehicle. In other words, detecting a change in the vehicle's transmission channel system can be used for monitoring the vehicle. A method according to the invention for detecting a change in the vehicle's transmission channel system with the at least one transmission channel for monitoring the vehicle can have, as an additional (activation) step, closing, in particular locking, the vehicle. Monitoring the vehicle is preferably interior and / or exterior monitoring of the vehicle. For example, theft protection can be ensured by monitoring, in particular interior monitoring. Furthermore, monitoring the vehicle can also be used to detect occupancy of at least one seat or several seats in the vehicle.A method according to the invention for detecting a change in the vehicle's transmission channel system with the at least one transmission channel for detecting occupancy of at least one seat can include, for example, unlocking the vehicle and / or starting a drive engine to move the vehicle as an additional (activation) step. It is also conceivable that monitoring the vehicle is or is used to detect at least one child or several children in the vehicle (child presence detection).

[0013] Furthermore, the detection of the change in the transmission channel system of the vehicle can be or be used in particular for monitoring a state of health, in particular respiration, of at least one living being in the vehicle.

[0014] In particular, a transmission channel of the transmission channel system is formed with respect to a transmitting unit and a receiving unit by the external and / or internal environment of the vehicle. The channel impulse response (CIR) can provide complete information about the influence of the transmission channel on the ultra-wideband transmission signal.

[0015] It is also conceivable for the transmission channel system to have multiple transmission channels. Thus, an area of ​​a vehicle that is "hidden" for one transmitting unit / receiving unit combination can be made "visible" by another transmitting unit / receiving unit combination. For example, a vehicle can have multiple transmitting units and one receiving unit, or the vehicle can comprise one transmitting unit and multiple receiving units to form multiple transmission channels. In particular, the vehicle can also have multiple transmitting units and multiple receiving units to form multiple transmission channels. Thus, the detection of a change in the transmission channel system can be particularly reliable.

[0016] The determination of a channel impulse response of a transmission channel of the vehicle's transmission channel system is preferably carried out by correlating, in particular cross-correlating, the received signal with the ultra-wideband transmitted signal. For example, the ultra-wideband transmitted signal can be stored in a memory of a radio module according to the invention or a radio system according to the invention for the correlation, in particular the cross-correlation, to determine the channel impulse response. Advantageously, the channel impulse response of the transmission channel can thus be determined particularly easily. Advantageously, a cross-correlation function obtained by cross-correlating the received signal with the ultra-wideband transmitted signal can represent the channel impulse response of the transmission channel. Furthermore, the channel impulse response is in particular a function of time, in particular a delay time.Based on the channel impulse response, possible multipath propagation of the ultra-wideband transmission signal can be detected, whereby the detection of possible multipath propagation depends in particular on the delay time for how long a channel impulse response is measured (temporal length of the transmission signal).

[0017] The correlation coefficient resulting from the determined channel impulse response and the known channel impulse response reflects, in particular, the similarity of the determined channel impulse response to the known channel impulse response. The correlation coefficient is, in particular, a cross-correlation coefficient of a cross-correlation function obtained by cross-correlating the determined channel impulse response with the known channel impulse response, very preferably a maximum cross-correlation coefficient of a cross-correlation function obtained by cross-correlating the determined channel impulse response with the known channel impulse response.

[0018] Since the ultra-wideband transmission signal is transmitted by the transmitting unit over a transmission channel, the ultra-wideband transmission signal can vary due to the transmission channel, so that the ultra-wideband transmission signal transmitted by the transmitting unit and the received signal received by the receiving unit can differ. Therefore, this document prefers to refer to cross-correlation and / or cross-correlation and / or cross-correlation coefficient instead of autocorrelation or autocorrelation or autocorrelation coefficient. However, it should also be noted that, particularly under special circumstances, cross-correlation can be understood as autocorrelation and / or that the cross-correlation coefficient can be understood as an autocorrelation coefficient and / or that the cross-correlation function can be understood as an autocorrelation function.

[0019] The respective adaptation of the determined channel impulse responses to a known channel impulse response of the vehicle to form a respective adapted channel impulse response can be understood in particular as forming a respective adapted channel impulse response by adapting a determined channel impulse response to a known channel impulse response of the vehicle. In other words, in particular, a determined channel impulse response, for example, a channel impulse response determined by correlating the received signal with the ultra-wideband transmitted signal, is adapted or aligned to a known channel impulse response of the vehicle, for example, a channel impulse response determined previously, thereby obtaining the respective adapted channel impulse response.

[0020] By filtering at least a part of the adapted channel impulse responses of at least one transmission channel in a time direction, a temporal change in the channel impulse response can be made recognizable.

[0021] In particular, by adapting at least a portion of the determined channel impulse responses of the plurality of channel impulse responses of the at least one transmission channel to a known channel impulse response of the at least one transmission channel of the vehicle, resulting in a respective adapted channel impulse response using an adaptation unit such that a correlation coefficient resulting from the determined channel impulse response and the known channel impulse response is increased, the similarity of the determined channel impulse response and the known channel impulse response is increased. Advantageously, technical tolerances and / or technical inaccuracies, e.g., of the radio module or the radio system, can thus be better considered at least partially to detect a "real" change in the vehicle's transmission channel system. For example, sampling inaccuracies can be better considered as technical inaccuracies.Thus, a "steady" temporal sequence can be generated across multiple channel impulse responses. In particular, a change in a transmission channel over time can be detected at at least one characteristic point or at several characteristic points of the channel impulse response(s). A characteristic point of the channel impulse response can be a local maximum of the channel impulse response. In particular, local maxima indicate time-delayed echoes and / or reflectors of the transmission channel. Consequently, a "real" change in at least one transmission channel of a transmission channel system can be better distinguished from an "apparent" change in the transmission channel based on technical tolerances and / or inaccuracies in a particularly simple, accurate, and reliable manner. Thus, even a small change in a transmission channel can advantageously be detected.This allows the vehicle to be monitored particularly precisely.

[0022] When referring to the expression "change in the transmission channel system," "change in the transmission channel," "detecting a change in the transmission channel system," "detecting a change in the transmission channel," or similar terms, it can generally be assumed that a "real" change is meant or that the expression refers to a "real" change. Where helpful for understanding or for emphasis, the word "real" or "apparent" is sometimes added.

[0023] It can be advantageous if, in a method according to the invention for detecting a change in the transmission channel system based on at least the specific filter signal of the at least one transmission channel, the specific filter signal of the at least one transmission channel is compared with a predefined signal for the at least one transmission channel. This makes it particularly easy, precise, and reliable to detect a change in the transmission channel of the transmission channel system. The predefined signal can, in particular, be a predefined, dynamic signal. The predefined, dynamic signal can change over time or be redetermined. In particular, the redetermination can be triggered by an action. If, for example, a vehicle is to be monitored, a redetermination of the predefined signal can be triggered as an action whenever the vehicle is closed, in particular locked.Advantageously, a changing environment, such as a changed interior environment of the vehicle, can thus be taken into account. An interior environment can change, for example, due to objects left behind by the driver of the vehicle.

[0024] Advantageously, in a method according to the invention for detecting changes in the transmission channel system, an average value can be formed from at least a portion of the specific filter signal of the at least one transmission channel, at least based on the specific filter signal of the at least one transmission channel, wherein the calculated average value is compared with a threshold value. Thus, a change in the transmission channel of the transmission channel system can be detected particularly reliably. In particular, the threshold value can be at least a multiple of a noise value based on the determined channel impulse responses. Furthermore, the threshold value is, in particular, a dynamic threshold value. The dynamic threshold value can change or be redetermined over time.If, for example, a vehicle is to be monitored, a new determination of the threshold value can be triggered each time the vehicle is closed, in particular locked. Advantageously, a changed environment, such as a changed interior environment of the vehicle, can thus be taken into account. Furthermore, at least one part of the specific filter signal of the at least one transmission channel is, in particular, buffered at least temporarily in order to be able to calculate the mean value from the buffered filter signal. The radio system, in particular the radio module, can, in particular, have a buffer for buffering. Furthermore, the formation of the mean value from at least one part of the specific filter signal of the at least one transmission channel is preferably a dynamic formation of the mean value.The dynamic calculation of the mean value from at least a portion of the specific filter signal can be carried out according to the "sliding window" principle. In this case, for example, in a buffer of the radio system, the oldest information from the specific filter signal of the filtered, matched channel impulse responses is replaced by newly received information from the specific filter signal of the filtered, matched channel impulse responses. This allows a change in the transmission channel of the transmission channel system to be detected particularly reliably.Furthermore, it is particularly conceivable that, in order to detect the change in the transmission channel system, a first mean value for a first time period is dynamically formed from the at least one part of the specific filter signal of the at least one transmission channel, in particular in the time direction, and that a second mean value for a second time period is dynamically formed from the at least one part of the specific filter signal of the at least one transmission channel, in particular in the time direction, wherein the first mean value and the second mean value are offset against one another to form a dynamic substitute value, and wherein the substitute value is compared with the threshold value, in particular a dynamic threshold value. A time period is to be understood in particular as a time duration in the time direction.In particular, the first time period is longer than the second time period, with the first time period and the second time period in particular overlapping. Thus, the first mean value advantageously changes more slowly over time than the second mean value. The first mean value can thus represent a baseline and serve as a low-pass filter. Preferably, the first mean value and the second mean value are subtracted from one another and a dynamic absolute value is formed, with the formed absolute value being compared with the threshold value in order to detect a change in the transmission channel system. In this way, a DC component can be eliminated in a simple manner. Furthermore, long-term drifts can be taken into account, so that in particular a fixed threshold value can also be used.Thus, for example, monitoring a health status, in particular respiration, of at least one living being in the vehicle can be particularly advantageous. For example, the breathing of a living being can intrinsically lead to a periodically or substantially periodically changing transmission channel, wherein a first mean value formed for a first time period from the specific filter signal of this transmission channel represents, in particular, a baseline. Subsequently, the first mean value and a second mean value are subtracted from one another, and a dynamic absolute value is formed, wherein the formed absolute value is compared with the threshold value.A now occurring ("additional") change in the periodically changing or essentially periodically changing transmission channel has a less pronounced effect on the first mean value with the longer time period than on the second mean value with the shorter time period. Thus, monitoring the health status, in particular respiration, of a living being can be carried out particularly advantageously.

[0025] Particularly advantageously, in a method according to the invention for the respective adaptation of at least a portion of the determined channel impulse responses to the known channel impulse response of the at least one transmission channel to increase the correlation coefficient, the determined channel impulse response can be shifted relative to the known channel impulse response of the transmission channel. This advantageously allows technical tolerances and / or technical inaccuracies, for example, technical inaccuracies in sampling the received signal, to be taken into account, so that a "real" change in a transmission channel can be detected in a particularly reliable manner. The shifting is preferably at least a 1-dimensional shift. The shifting can also be a multi-dimensional shift.The (1-dimensional) shifting is, in particular, a shift of the determined channel impulse response relative to the known channel impulse response in a delay time direction. This advantageously allows technical inaccuracies, for example, technical inaccuracies in sampling the received signal, to be taken into account in a particularly advantageous manner. Thus, a "steady" temporal sequence of multiple channel impulse responses can be generated, wherein, in particular, the multiple channel impulse responses are particularly advantageously aligned with one another at at least one characteristic location or locations. In particular, the determined channel impulse response is shifted relative to the known channel impulse response of the transmission channel in such a way that the similarity between the determined channel impulse response and the known channel impulse response is increased.Very preferably, the determined channel impulse response is shifted relative to the known channel impulse response of the transmission channel in a delay time direction such that a cross-correlation has an increased value, in particular the maximum value. Furthermore, the shifting of the determined channel impulse response relative to the known channel impulse response of the transmission channel can be a relative shift to each other.

[0026] According to a further preferred embodiment, in a method according to the invention for the respective adaptation of at least a portion of the determined channel impulse responses of the at least one transmission channel to the known channel impulse response of the at least one transmission channel in order to increase the correlation coefficient, the determined channel impulse response can be scaled with respect to the known channel impulse response of the transmission channel. Advantageously, technical tolerances and / or technical inaccuracies, for example, technical inaccuracies in sampling the received signal, can thus be taken into account, so that a "real" change in a transmission channel can be detected in a particularly reliable manner. In particular, amplitude fluctuations of channel impulse responses, which are caused by non-identical sampling times for the ultra-wideband transmitted signal and the received signal, can be compensated for in an improved manner.In particular, a characteristic point of the determined channel impulse response is scaled, in particular normalized, with respect to a corresponding characteristic point of the known channel impulse response of the transmission channel. Preferably, an amplitude of the determined channel impulse response is scaled, in particular normalized, as a characteristic point with respect to an amplitude of the known channel impulse response as a corresponding characteristic point.

[0027] It can be advantageous if, in a method according to the invention for the respective adaptation of at least a portion of the determined channel impulse responses of the at least one transmission channel to the known channel impulse response of the at least one transmission channel to increase the correlation coefficient, the determined channel impulse response is interpolated in order to add at least one auxiliary sampling point between two sampling points of the determined channel impulse response. Advantageously, this can increase the temporal resolution of the determined channel impulse response, so that a "real" change in a transmission channel can be more effectively detected. In particular, a determined channel impulse response is a discrete-time signal or a discrete-time function with multiple sampling points. The temporal resolution of the channel impulse response can be limited by technical constraints, for example, the sampling frequency.By interpolating the determined channel impulse response, several additional auxiliary sampling points can be added between the several sampling points of the determined channel impulse response. On the one hand, the course of the channel impulse response over the delay time can thus be smoothed, and the correlation coefficient resulting from the determined channel impulse response and the known channel impulse response can thus be increased. On the other hand, a shifting of the determined channel impulse response to the known channel impulse response can advantageously be carried out in smaller (time) steps in an improved manner. Thus, the determined channel impulse response to the known channel impulse response of the transmission channel can be shifted in such a way that the similarity between the determined channel impulse response and the known channel impulse response is increased.Very preferably, the determined channel impulse response is shifted in a delay time direction relative to the known channel impulse response of the transmission channel such that a cross-correlation has an increased value, in particular the maximum value. Preferably, a polynomial is inserted between each two support points, in particular between each two adjacent support points, of the plurality of support points of the determined channel impulse response in order to add at least one auxiliary support point between the two support points, in particular between two adjacent support points. The polynomial is preferably a third-order polynomial. If the known channel impulse response is based on a previously determined channel impulse response of the at least one transmission channel, the determined channel impulse response is interpolated in particular identically or substantially identically to the known channel impulse response.The determined channel impulse response and the known channel impulse response can thus have the same or essentially the same time resolution in the delay direction. This makes shifting particularly easy.

[0028] Advantageously, in a method according to the invention, at least some of the determined channel impulse responses of the plurality of channel impulse responses of the at least one transmission channel can each be adapted to a channel impulse response of the at least one transmission channel based on a previously determined channel impulse response. This makes it particularly easy and reliable to detect a change in the transmission channel of the transmission channel system. The channel impulse response based on a previously determined channel impulse response is to be understood in particular as the known channel impulse response of the at least one transmission channel, to which a determined channel impulse response is adapted according to the invention. In particular, a respective known channel impulse response, to which a respective determined channel impulse response is adapted, can be a dynamic channel impulse response.The channel impulse response determined in advance can, for example, be the channel impulse response determined immediately before the respective channel impulse response determined.

[0029] Particularly advantageously, in a method according to the invention, at least some of the determined channel impulse responses of the plurality of channel impulse responses of the at least one transmission channel can be adapted to the same known channel impulse response of the at least one transmission channel. Advantageously, a "real" change in a transmission channel can thus be detected in a particularly simple and rapid manner. In particular, the same known channel impulse response of the at least one transmission channel can be a channel impulse response based on at least one previously determined channel impulse response. Furthermore, in particular, the same known channel impulse response can be dynamic. In other words, the same known channel impulse response can change or be redefined over time; for example, the same known channel impulse response can be redefined after a definable number of channel impulse responses.If, for example, a vehicle is to be monitored, the same known channel impulse response can be redefined each time the vehicle is closed, in particular locked.

[0030] According to a further preferred embodiment, in a method according to the invention, a determined channel impulse response of the plurality of channel impulse responses of the at least one transmission channel can be adapted to the known channel impulse response of the at least one transmission channel of the respective adapted channel impulse response in such a way that the correlation coefficient resulting from the determined channel impulse response and the known channel impulse response is maximized. Thus, a change in a transmission channel system or at least one transmission channel of the transmission channel system can be detected particularly accurately and reliably.In particular, a determined channel impulse response of the plurality of channel impulse responses of the at least one transmission channel is adapted to the known channel impulse response of the at least one transmission channel of the respective adapted channel impulse response such that a cross-correlation coefficient of a cross-correlation function obtained by cross-correlating the determined channel impulse response with the known channel impulse response is maximized or substantially maximized. The adaptation of a determined channel impulse response to the known channel impulse response can in particular be a shifting of the determined channel impulse response in a delay time direction and / or a scaling of the determined channel impulse response, in particular in the amplitude direction of the channel impulse response, and / or an interpolation of the determined channel impulse response. Thus, a change in a transmission channel system orat least one transmission channel of the transmission channel system can be detected particularly accurately and reliably.

[0031] It can be advantageous if, in a method according to the invention, at least a portion of the adapted channel impulse responses of the at least one transmission channel is filtered in the time direction using a high-pass filter. Advantageously, a constant component of the adapted channel impulse responses can thus be filtered out in the time direction, and a change in the at least one transmission channel can be detected particularly easily. In particular, the high-pass filtering of at least a portion of the adapted channel impulse responses in the time direction is performed for corresponding sampling points or auxiliary sampling points of the channel impulse responses.

[0032] Advantageously, in a method according to the invention, the ultra-wideband transmission signal can have at least one sounding signal, preferably at least two different sounding signals. Thus, a particularly advantageous channel impulse response can be determined, and a change in a transmission channel system or at least one transmission channel of the transmission channel system can be detected particularly reliably. A sounding signal is, in particular, a specific compressed, periodic pulse signal that has particularly advantageous cross-correlation properties. The at least one sounding signal is preferably an Ipatov sequence. Advantageously, by cross-correlating an Ipatov sequence as an ultra-wideband transmission signal with the same Ipatov sequence, the channel impulse response of the at least one transmission channel can be determined particularly precisely.Furthermore, it is conceivable for the ultra-wideband transmission signal to comprise a plurality of sounding signals, in particular a plurality of different sounding signals, preferably a plurality of different Ipatov sequences. The plurality of sounding signals are transmitted, in particular, alternately one after the other, wherein, based on the plurality of sounding signals, the channel impulse responses are determined and / or adapted and / or filtered in a manner according to the invention. Thus, a change in a transmission channel system or at least one transmission channel of the transmission channel system can be detected particularly reliably.

[0033] According to a further preferred embodiment, in a method according to the invention, several adapted channel impulse responses of the at least one transmission channel of the vehicle can be combined, in particular averaged, to form a substitute channel impulse response prior to filtering. Advantageously, technical tolerances and / or technical inaccuracies, for example, technical inaccuracies in sampling the received signal, can thus be taken into account in an improved manner, so that a "real" change in a transmission channel can be detected in a particularly reliable manner. In particular, several adapted, temporally consecutive channel impulse responses of the at least one transmission channel of the vehicle can be combined, in particular averaged, to form the substitute channel impulse response. In other words, several adapted channel impulse responses can be combined in the temporal direction to form the substitute channel impulse response.If the ultra-wideband transmission signal comprises several different sounding signals, it is also conceivable, in particular, for adapted, temporally successive channel impulse responses of the at least one transmission channel of the vehicle based thereon to be combined, in particular averaged, to form the substitute channel impulse response. In particular, it is also conceivable for several adapted channel impulse responses to be combined during the delay time to form the substitute channel impulse response.

[0034] It can be advantageous if, in a method according to the invention, several receiving units each receive a received signal based on the transmitted ultra-wideband transmission signal in order to detect the change in the vehicle's transmission channel system. Thus, an area of ​​a vehicle that is "hidden" for one transmitting unit / receiving unit combination can be made "visible" by means of another transmitting unit / receiving unit combination, so that the detection of a change in the transmission channel system is particularly reliable. The several receiving units are arranged spatially separated from one another, in particular spatially separated from one another in and / or on the vehicle. Based on the respective received signal of the several receiving units, channel impulse responses of the respective transmission channel of the vehicle can be determined.According to the invention, the respectively determined channel impulse responses can be adapted and / or filtered to detect a change in the transmission channel system based on a specific filter signal of a respective transmission channel. A change in the transmission channel system is present, in particular, upon detection of a change in at least one transmission channel of the transmission channel system. Furthermore, in particular, the at least one transmitting unit for transmitting the ultra-wideband transmission signal and a receiving unit for receiving the received signal based on the ultra-wideband transmission signal can form a module, in particular co-form a radio module.

[0035] Advantageously, in a method according to the invention, several transmitting units can each transmit an ultra-wideband transmission signal to detect changes in the vehicle's transmission channel system. Thus, an area of ​​a vehicle that is "hidden" for one transmitting unit-receiving unit combination can be made "visible" by another transmitting unit-receiving unit combination, so that the detection of changes in the transmission channel system is particularly reliable. The several transmitting units are arranged spatially separated from one another, in particular arranged spatially separated from one another in and / or on the vehicle.

[0036] Particularly advantageously, in a method according to the invention, the ultra-wideband transmission signals can be transmitted with a time delay using the multiple transmission units. This allows for particularly reliable detection of a change in the transmission channel system. For this purpose, a transmission unit for transmitting the ultra-wideband transmission signal and a reception unit for receiving the reception signal based on the ultra-wideband transmission signal preferably form a module. Thus, the modules can successively assume the function of the transmitter, with the non-transmitting modules each assuming the function of the receiver. Thus, a plurality of transmission channels can be generated, and detection of a change in the transmission channel system can be particularly advantageous.

[0037] According to a second aspect, the present invention provides a radio module for a radio system for detecting a change in a transmission channel system of a vehicle having at least one transmission channel, wherein the radio module has at least one receiving unit for receiving a received signal based on the ultra-wideband transmission signal. Furthermore, the radio module comprises a determination unit for determining at least one channel impulse response of at least one transmission channel of the vehicle based on the received signal, and an adaptation unit for adapting at least one determined channel impulse response of a plurality of channel impulse responses to a known channel impulse response of the at least one transmission channel of the vehicle to form a respective adapted channel impulse response such that a correlation coefficient resulting from the determined channel impulse response and the known channel impulse response is increased.The radio module also has a filter unit for filtering at least a portion of the matched channel impulse responses of at least one transmission channel in a temporal direction to obtain a specific filter signal of the filtered, matched channel impulse responses of the at least one transmission channel. Furthermore, the radio module comprises a detection unit for detecting changes in the transmission channel system based at least on the specific filter signal of the at least one transmission channel. The radio module can further comprise at least one transmission unit for transmitting an ultra-wideband transmission signal.

[0038] The radio module is specifically designed for monitoring the vehicle. In other words, the radio module can be used for monitoring the vehicle.

[0039] The radio module, comprising the receiving unit, the detection unit, the adaptation unit, the filter unit, and the recognition unit, forms a structural unit for the vehicle. This allows for particularly simple and energy-efficient monitoring of the vehicle, since, for example, a vehicle control unit can be shut down or put into sleep mode. A radio system according to the invention comprises several such radio modules.

[0040] Furthermore, it is conceivable for the radio module to comprise a transmitting unit as a structural unit in addition to the receiving unit, the detection unit, the adaptation unit, the filtering unit, and the recognition unit. Thus, the radio module can function as a transmitting and / or receiving unit. In particular, a radio system can comprise several such radio modules.

[0041] Upon detecting a change in the transmission channel system or upon detecting a change in at least one transmission channel, the detection unit, in particular of the radio module or the radio system, can send a control signal to a vehicle control unit based at least on the specific filter signal of the at least one transmission channel in order to trigger a definable response. For example, an alarm can be triggered when the vehicle is being monitored. It is also conceivable that a definable response is only triggered when a plurality of changes in the at least one transmission channel are detected.

[0042] The radio module according to the second aspect of the invention thus has the same advantages as have already been described for the inventive method according to the first aspect of the invention.

[0043] According to a third aspect, the present invention shows a radio system for detecting a change in a transmission channel system of a vehicle having at least one transmission channel, wherein the radio system is designed to carry out a method according to the invention.

[0044] The radio system is specifically designed for monitoring a vehicle. In other words, the radio system can be used for monitoring a vehicle.

[0045] The radio system according to the invention preferably has at least one transmitting unit and at least one receiving unit. However, it is also conceivable for the radio system to have multiple transmitting units and / or multiple receiving units. Particularly in a radio system for monitoring a vehicle, the at least one receiving unit is part of a radio module according to the invention, which comprises the receiving unit, a detection unit, an adaptation unit, a filter unit, and a recognition unit as a structural unit.

[0046] The radio system has, in particular, at least one receiving unit and / or a determination unit and / or an adaptation unit and / or a filter unit and / or a recognition unit and / or a transmission unit. In particular, the receiving unit and / or the determination unit and / or the adaptation unit and / or the filter unit and / or the recognition unit and / or the transmission unit can be arranged in a fixed location in and / or on the vehicle. It is also conceivable for a mobile body of the vehicle, for example a vehicle key, to form at least part of the radio system. In particular, the mobile body can have the receiving unit and / or the determination unit and / or the adaptation unit and / or the filter unit and / or the recognition unit and / or the transmission unit.

[0047] If the radio system has multiple receiving units arranged at separate locations, the radio system can have a common detection unit and / or adaptation unit and / or filter unit and / or recognition unit for the multiple transmission channels. This allows the radio system to be particularly compact and cost-effective.

[0048] It may further be advantageous if a radio system according to the invention has at least one radio module according to the invention, as well as at least one transmission unit for transmitting a transmission signal, in particular an ultra-wideband transmission signal, via a transmission channel system.

[0049] The radio system according to the third aspect of the invention thus has the same advantages as have already been described for the method according to the first aspect of the invention or the radio module according to the second aspect of the invention.

[0050] Further measures improving the invention will become apparent from the following description of some exemplary embodiments of the invention, which are schematically illustrated in the figures. All features and / or advantages apparent from the claims, the description, or the drawings, including design details, spatial arrangements, and method steps, may be essential to the invention both individually and in various combinations. It should be noted that the figures are merely descriptive and are not intended to limit the invention in any way.

[0051] The invention is explained in more detail below with reference to the accompanying drawings. In the drawings: Fig. 1 shows an embodiment of a method according to the invention, Fig. 2 shows further embodiments of a method according to the invention, Fig. 3 shows an embodiment of a method according to the invention, Fig. 4 shows further embodiments of a method according to the invention, Fig. 5 shows an embodiment of a radio module according to the invention, Fig. 6 shows an embodiment of a radio system according to the invention, and Fig. 7 shows, by way of example, a plurality of adapted channel impulse responses of a transmission channel over time.

[0052] In the following figures, identical reference numerals are used for the same technical features, even in different embodiments.

[0053] Figure 1shows an embodiment of a method according to the invention for detecting 600 a change in a transmission channel system of a vehicle having at least one transmission channel. The method comprises, as one step, transmitting 100 an ultra-wideband transmission signal by means of a transmitting unit 10 via the transmission channel system, and, as a further step, receiving 200 at least one received signal based on the ultra-wideband transmission signal by means of a receiving unit 20, and, as a further step, determining 300 at least one channel impulse response of the at least one transmission channel of the vehicle based on the received signal by means of a determination unit 30. These steps just mentioned, i.e., transmitting 100, receiving 200, and determining 300, are repeated several times in order to determine 300 at least a plurality of channel impulse responses of the at least one transmission channel.In other words, a plurality of channel impulse responses are determined over time. A further step of the method according to the invention is a respective adaptation 400 of at least a portion of the determined channel impulse responses of the plurality of channel impulse responses of the at least one transmission channel to a known channel impulse response of the at least one transmission channel of the vehicle to form a respective adapted channel impulse response by means of an adaptation unit 40 such that a correlation coefficient resulting from the determined channel impulse response and the known channel impulse response is increased. By means of this step according to the invention, a plurality of determined channel impulse responses of the at least one transmission channel can be adapted to one another, in particular shifted and / or scaled and / or interpolated 400, in such a way that, for example, technical inaccuracies such as sampling inaccuracies of a receiving unit 20 can be compensated for or eliminated in an improved manner.be taken into account. Thus, a "steady" temporal sequence of multiple channel impulse responses can be generated, and detection of a "real" change in a vehicle's transmission channel system can be particularly simple, accurate, and / or reliable. In particular, at least some of the determined channel impulse responses of the plurality of channel impulse responses of the at least one transmission channel can each be adapted 400 to a channel impulse response of the at least one transmission channel based on a previously determined channel impulse response. Alternatively or additionally, it is also conceivable for at least some of the determined channel impulse responses of the plurality of channel impulse responses of the at least one transmission channel to be adapted to the same known channel impulse response of the at least one transmission channel.The method comprises, as a further step, filtering 500 at least a portion of the adapted channel impulse responses of at least the at least one transmission channel in a temporal direction by means of a filter unit 50 to obtain a specific filter signal of the filtered, adapted channel impulse responses of the at least one transmission channel. The filtering can be carried out, in particular, by means of a high-pass filter. Furthermore, the method according to the invention comprises, as a further step, detecting 600 the change in the transmission channel system at least based on the specific filter signal of the at least one transmission channel by means of a detection unit 60. In addition, upon detecting a change in the transmission channel system, the detection unit 60 can send a control signal to a control unit, in particular a vehicle control unit, in order to trigger a corresponding reaction, for example, an alarm.The method according to the invention can be used to monitor a vehicle.

[0054] Figure 2 shows further embodiments of a method according to the invention for detecting 600 a change in a transmission channel system of a vehicle with at least one transmission channel, wherein the methods in Figure 2 also the Figure 1have the steps mentioned above. Furthermore, in a method according to the invention for the respective adaptation 400 of at least a portion of the determined channel impulse responses of the at least one transmission channel to the known channel impulse response of the at least one transmission channel in order to increase the correlation coefficient, the determined channel impulse response can be interpolated 410 in order to add at least one auxiliary sampling point between two sampling points of the determined channel impulse response. Furthermore, in a method according to the invention for the respective adaptation 400 of at least a portion of the determined channel impulse responses of the at least one transmission channel to the known channel impulse response of the at least one transmission channel in order to increase the correlation coefficient, the determined channel impulse response can be scaled 420 with respect to the known channel impulse response of the transmission channel.Furthermore, in a method according to the invention for the respective adaptation 400 of at least one part of the determined channel impulse responses to the known channel impulse response of the at least one transmission channel in order to increase the correlation coefficient, the determined channel impulse response can be shifted 430 to the known channel impulse response of the transmission channel. Preferably, all three steps, ie interpolation 410, scaling 420 and shifting 430, are carried out.A preferred sequence of these steps is, in particular, that first a determined channel impulse response is interpolated 410, then the determined channel impulse response is scaled 420 with respect to the known channel impulse response, and then the determined channel impulse response is shifted 430 with respect to the known channel impulse response, wherein these steps are carried out in such a way that a correlation coefficient resulting from the determined channel impulse response and the known channel impulse response is increased, wherein in particular the correlation coefficient is increased after the last of the three steps.

[0055] Figure 3 shows a further embodiment of a method according to the invention for detecting 600 a change in a transmission channel system of a vehicle with at least one transmission channel, wherein the method in Figure 3 also the Figure 1 and / or Figure 2additionally has or can have the steps mentioned. Furthermore, in a method according to the invention, a plurality of adapted channel impulse responses of the at least one transmission channel of the vehicle can be offset against one another 490 to form a substitute channel impulse response prior to filtering 500. In particular, a plurality of adapted, temporally successive channel impulse responses of the at least one transmission channel of the vehicle can be offset against one another, in particular averaged 490, to form the substitute channel impulse response. In this way, a particularly content-rich channel impulse response can be obtained and, furthermore, a particularly "calm" temporal sequence of a plurality of substitute channel impulse responses can be generated, and detection of a "real" change in a transmission channel system of a vehicle can be particularly advantageous.

[0056] Figure 4shows further embodiments of a method according to the invention for detecting 600 a change in a transmission channel system of a vehicle with at least one transmission channel, wherein the methods in Figure 4 also the Figure 1 and / or Figure 2 and / or Figure 3mentioned steps. Furthermore, in a method according to the invention for detecting 600 the change in the transmission channel system based on at least the specific filter signal of the at least one transmission channel, the specific filter signal of the at least one transmission channel can be compared 560 with a predetermined signal for the at least one transmission channel. In particular, an average value can be formed 550 from at least a portion of the specific filter signal of the at least one transmission channel, wherein the formed average value is compared 570 with a threshold value.Furthermore, it is particularly conceivable that, in order to detect 600 the change in the transmission channel system, a first mean value for a first time period is dynamically formed from the at least part of the specific filter signal of the at least one transmission channel in the time direction, and that a second mean value for a second time period is dynamically formed from the at least part of the specific filter signal of the at least one transmission channel in the time direction, wherein the first time period is longer in time than the second time period. The first mean value can thus represent a baseline and be used for further low-pass filtering. Preferably, the first mean value and the second mean value are subtracted from one another and an absolute value is formed, wherein the formed absolute value is compared with the threshold value in order to detect a change in the transmission channel system.In particular, the threshold value can be at least a multiple of a noise value based on the determined channel impulse responses. This allows a change in the transmission channel of the transmission channel system to be detected particularly reliably.

[0057] Figure 5shows an embodiment of a radio module 1 according to the invention for a radio system 90 for detecting a change in a transmission channel system of a vehicle having at least one transmission channel, wherein the radio module 1 has at least one receiving unit 20 for receiving a received signal based on the ultra-wideband transmission signal. Furthermore, the radio module 1 comprises a determination unit 30 for determining at least one channel impulse response of at least one transmission channel of the vehicle based on the received signal, as well as an adaptation unit 40 for adapting at least one determined channel impulse response of a plurality of channel impulse responses to a known channel impulse response of the at least one transmission channel of the vehicle to form a respective adapted channel impulse response such that a correlation coefficient resulting from the determined channel impulse response and the known channel impulse response is increased.Furthermore, the radio module 1 has a filter unit 50 for filtering at least a portion of the adapted channel impulse responses of at least one transmission channel in a temporal direction to obtain a specific filter signal of the filtered, adapted channel impulse responses of the at least one transmission channel. Furthermore, the radio module comprises a detection unit 60 for detecting the change in the transmission channel system based at least on the specific filter signal of the at least one transmission channel. In particular, the receiving unit 20, the determination unit 30, the adaptation unit 40, the filter unit 50, and the detection unit 60 form a structural unit.

[0058] Figure 6shows an embodiment of a radio system 90 according to the invention for detecting a change in a transmission channel system of a vehicle with at least one transmission channel, wherein the radio system 90 is designed to carry out a method according to the invention for detecting a change in a transmission channel system. The radio system 1 has, in particular, at least one radio module 1 according to the invention as already described in Figure 5 described, as well as at least one transmitting unit 10 for transmitting a transmission signal, in particular an ultra-wideband transmission signal, via a transmission channel system. The radio system 1 can also have multiple transmitting units 10 for each transmitting an ultra-wideband transmission signal and / or multiple receiving units 20 for each receiving a reception signal based on an ultra-wideband transmission signal. Thus, the detection of a change in the transmission channel system can be particularly reliable.

[0059] Figure 7shows, by way of example, a plurality, in particular a multiplicity, of channel impulse responses adapted according to the invention over time. An individual adapted channel impulse response is a function over a delay time. Multipath propagation of the ultra-wideband transmission signal of the channel impulse response can be identified using the delay time. In particular, the local maxima indicate time-delayed echoes and / or reflectors of the transmission channel. By adapting the determined channel impulse responses according to the invention to a known channel impulse response of the at least one transmission channel of the vehicle to the illustrated adapted channel impulse responses, for example, technical inaccuracies of a receiving unit such as sampling inaccuracies and the associated time shifts in the delay time direction and / or absolute amplitude fluctuations are taken into account.This allows a "steady" temporal sequence of multiple channel impulse responses to be generated over time. In particular, at least one characteristic point, for example, a maximum of the matched channel impulse responses, can be identified, making a change in a transmission channel over time particularly advantageous. Figure 7 It is evident from the channel impulse responses adapted according to the invention that the transmission channel has changed at least once over time, for example at time t1 or in a time range around time t1. The maximum of the adapted channel impulse responses at a (determinable) delay time indicates a recognizable change (see arrow in Figure 7 ) in amount, namely an increase. List of reference symbols

[0060] 1 Radio module 10 Transmitter unit 20 Receiver unit 30 Detection unit 40 Adaptation unit 50 Filter unit 60 Detection unit 90 Radio system 100Transmitting an ultra-wide transmission signal 200Receiving a reception signal 300Determining at least one channel impulse response of the transmission channel 400Adapting a determined channel impulse response to a known channel impulse response 410Interpolating the determined channel impulse response 420Scaling the determined channel impulse response with respect to the known channel impulse response 430Shifting the determined channel impulse response to the known channel impulse response 490Averaging a plurality of adapted channel impulse responses 500Filtering at least a portion of the plurality of adapted channel impulse responses in a time direction 550Forming an average value from at least a portion of the plurality of filtered channel impulse responses 560Comparing the specific filter signal with a predetermined signal 570Comparing the formed average value with a threshold value 600Detecting the change in the transmission channel t1 time point

Claims

1. A method for detecting (600) a change in a communications channel system of a motor vehicle with at least one communications channel, the said method comprising the following steps: a) Transmitting (100) an ultra-wideband transmission signal by means of a transmission unit (10) via the communications channel system, b) Receiving (200) at least one reception signal based on the ultra-wideband transmission signal by means of a reception unit (20), c) Determining (300) at least one channel impulse response of the at least one communications channel of the motor vehicle based on the reception signal by means of a determination unit (30), - Repeating steps a) to c) several times to determine (300) at least one plurality of channel impulse responses of the at least one communications channel, - Respectively adapting (400) at least a part of the determined channel impulse responses of the plurality of channel impulse responses of the at least one communications channel to a known channel impulse response of the at least one communications channel of the motor vehicle to a respective adapted channel impulse response by means of an adaptation unit (40) in such a way that a correlation coefficient resulting from the determined channel impulse response and the known channel impulse response increases, - Filtering (500) the at least one part of the adapted channel impulse responses at least of the at least one communications channel in a time direction by means of a filter unit (50) to obtain a specific filter signal of the filtered, adapted channel impulse responses of the at least one communications channel, - Detecting (600) the change in the communications channel system at least on the basis of the specific filter signal of the at least one communications channel by means of a detection unit (60).

2. A method according to claim 1, in which for detection (600) of the change in the communications channel system by means of at least the specific filter signal of the at least one communications channel, the specific filter signal of the at least one communications channel is compared (560) with a predetermined signal for the at least one communications channel.

3. A method according to claim 1 or 2, in which for detection (600) of the change in the communications channel system by means of at least the specific filter signal of the at least one communications channel, a mean value is formed (550) from at least a part of the specific filter signal of the at least one communications channel, said mean value formed being compared (570) with a threshold value.

4. A method according to one of the previous claims, in which for the respective adaptation (400) of the at least one part of the determined channel impulse responses to the known channel impulse response of the at least one communications channel for increasing the correlation coefficient, the determined channel impulse response is shifted (430) to the known channel impulse response of the communications channel.

5. A method according to one of the previous claims, in which for the respective adaptation (400) of the at least one part of the determined channel impulse responses of the at least one communications channel to the known channel impulse response of the at least one communications channel for increasing the correlation coefficient, the determined channel impulse response is scaled (420) in relation to the known channel impulse response of the communications channel.

6. A method according to one of the previous claims, in which for the respective adaptation (400) of the at least one part of the determined channel impulse responses of the at least one communications channel to the known channel impulse response of the at least one communications channel for increasing the correlation coefficient, the determined channel impulse response is interpolated (410) in order to add at least one auxiliary support point between two support points of the determined channel impulse response.

7. A method according to one of the previous claims, in which at least a part of the determined channel impulse responses of the plurality of channel impulse responses of the at least one communications channel are each adapted (400) to a channel impulse response of the at least one communications channel based on a channel impulse response determined at an earlier point in time.

8. A method according to one of the previous claims, in which at least a part of the determined channel impulse responses of the plurality of channel impulse responses of the at least one communications channel is adapted (400) to the same known channel impulse response of the at least one communications channel.

9. A method according to one of the previous claims, in which a determined channel impulse response of the plurality of channel impulse responses of the at least one communications channel is adapted (400) to the known channel impulse response of the at least one communications channel of the respective adapted channel impulse response in such a way that the correlation coefficient resulting from the determined channel impulse response and the known channel impulse response is maximized.

10. A method according to one of the previous claims, in which filtering (500) of at least a part of the adapted channel impulse responses of the at least one communications channel is carried out in time direction by means of a high-pass filter.

11. A method according to one of the previous claims, in which the ultra-wideband transmission signal has at least one sounding signal, preferably at least two different sounding signals.

12. A method according to one of the previous claims, in which a plurality of adapted channel impulse responses of the at least one communications channel of the motor vehicle are offset with one another, in particular averaged (490) to form a substitute channel impulse response temporally prior to filtering (500).

13. A method according to one of the previous claims, in which a plurality of reception units (20) each receive a reception signal based on the transmitted ultra-wideband transmission signal in order to detect (600) the change in the communications channel system of the motor vehicle.

14. A method according to one of the previous claims, in which a plurality of transmission units (10) each transmit an ultra-wideband transmission signal in order to detect (600) the change in the communications channel system of the motor vehicle.

15. A method according to claim 14, in which the transmission of the ultra-wideband transmission signals by means of the plurality of transmission units (10) is staggered in time.

16. A radio module (1) for a radio system (90) for detecting a change in a communications channel system of a motor vehicle having at least one communications channel in which the radio module (1) comprises: - at least one reception unit (20) for receiving a reception signal based on an ultra-wideband transmission signal, - a determination unit (30) for determining at least one channel impulse response of at least one communications channel of the motor vehicle based on the reception signal, - an adaptation unit (40) for adapting at least one determined channel impulse response of a plurality of channel impulse responses to a known channel impulse response of the at least one communications channel of the motor vehicle to a respective adapted channel impulse response in such a way that a correlation coefficient resulting from the determined channel impulse response and the known channel impulse response increases, - a filter unit (50) for filtering at least a part of the adapted channel impulse responses at least of the at least one communications channel in a time direction to obtain a specific filter signal of the filtered, adapted channel impulse responses of the at least one communications channel, - a detection unit (60) for detecting the change in the communications channel system at least on the basis of the specific filter signal of the at least one communications channel, - at least one transmission unit (10) for transmitting an ultra-wideband transmission signal.

17. A radio system (90) for detecting a change in a communications channel system of a motor vehicle having at least one communications channel, said radio system (90) being designed to perform a method according to one of claims 1 to 15, characterized in that the radio system (90) comprises: - multiple radio modules (1) according to claim 16, - at least one transmission unit (10) for transmitting a transmission signal, in particular an ultra-wideband transmission signal, via a communications channel system.