Key generation method and device based on radar perception

Abstract

The invention provides a secret key generation method and device based on radar perception, and the method comprises the steps: receiving a speed measurement signal reflected by a target through a radar, and obtaining the radial relative movement speed of the target relative to the radar based on the speed measurement signal; receiving a ranging signal reflected by the target through the radar, and obtaining direct path propagation time between the target and the radar based on the ranging signal; based on the radial relative movement speed, determining a minimum value of coherence time of a channel with the target side; determining the coherent bandwidth of the channel based on the direct path propagation time; obtaining a detection interval for detecting a channel based on the minimum value of the coherence time and the coherence bandwidth; based on the probe interval, a symmetric key is generated that communicates with the target party. According to the method, the real channel is directly measured based on the radar, the coherence time and the coherence bandwidth are calculated in real time, different communication scenes are supported, switching of the communication scenes is adapted, and after the communication scenes are switched, the two communication parties can update the secret key based on the switched channel characteristics in time.

Description

Technical Field

[0001] This application belongs to the field of wireless communication technologies, and particularly relates to a method and apparatus for generating keys based on radar sensing. Background Art

[0002] In the field of modern communication security, communication parties usually use symmetric keys to ensure the confidentiality of data during transmission. By utilizing the physical characteristics of the wireless channel, such as channel reciprocity, randomness, etc., symmetric keys can be directly generated between the communication parties.

[0003] A key generation scheme is provided in the related art. For a given communication scenario, a statistical channel model is established. This model is based on historical data and theoretical analysis of the channel behavior in this specific scenario and can describe the main characteristics of the channel. According to the tap gain autocorrelation function of this statistical channel model, the coherence time and coherence bandwidth in this scenario are calculated. Based on the calculated coherence time and coherence bandwidth, a detection interval is selected. Then, the channel characteristics are detected at this detection interval, and the detected channel characteristics are quantized to extract information available for key generation. Subsequently, the communication parties reach an agreement through an information negotiation process to ensure that they generate the same key based on the same channel state information.

[0004] However, the above statistical channel model is established based on a given communication scenario, and the detection interval obtained using this statistical channel model is only applicable to this given communication scenario. In practical applications, the communication scenario may change, such as switching from a stationary scenario to a mobile scenario, or from an urban area to a rural area, etc. In the case of a communication scenario switch, the originally set detection interval using the above statistical channel model is no longer applicable. At this time, to adjust the detection interval to adapt to the new communication scenario, a new statistical channel model needs to be established based on the new communication scenario. This not only increases the complexity and maintenance cost of the system but may also lead to key generation consistency problems, especially in the case of frequent scenario switches. Therefore, the solution in the above related art lacks flexibility and cannot automatically adjust the detection interval according to the real-time monitored channel parameters. In a rapidly changing environment, the change speed of channel characteristics may exceed the system's ability to update the detection interval, resulting in the key generation process being unable to respond to channel changes in a timely manner, ultimately affecting the quality and consistency of the keys. Summary of the Invention

[0005] Based on the above technical problems, this application proposes a method and apparatus for generating keys based on radar sensing, which realizes direct measurement of the real channel based on radar, can perform real-time calculation of the coherence time and coherence bandwidth of the channel, thus can support different communication scenarios, can adapt to the situation of frequent switching of communication scenarios, and can modify the detection interval in a timely manner as the communication scenario switches.

[0006] An embodiment of the first aspect of the present application provides a key generation method based on radar sensing, and the method includes:

[0007] Receiving a speed measurement signal reflected by a target party through a radar, and obtaining a radial relative motion speed of the target party relative to the radar based on the speed measurement signal;

[0008] Receiving a ranging signal reflected by the target party through the radar, and obtaining a direct path propagation time between the target party and the radar based on the ranging signal;

[0009] Determining a minimum value of the coherence time of the channel between the target party based on the radial relative motion speed; and determining the coherence bandwidth of the channel based on the direct path propagation time;

[0010] Obtaining a detection interval for detecting the channel based on the minimum coherence time and the coherence bandwidth;

[0011] Generating a symmetric key for communicating with the target party based on the detection interval.

[0012] In some embodiments of the present application, the obtaining of the radial relative motion speed of the target party relative to the radar based on the speed measurement signal includes:

[0013] Uniformly sampling the speed measurement signal in additive complex Gaussian white noise;

[0014] Representing the sampled signal in terms of normalized frequency to obtain a speed measurement signal in the normalized frequency domain;

[0015] Performing a discrete Fourier transform on the speed measurement signal in the normalized frequency domain to obtain a transformed speed measurement signal in the frequency domain;

[0016] Obtaining a normalized frequency estimate value when the transformed speed measurement signal in the frequency domain takes the maximum amplitude;

[0017] Calculating the radial relative motion speed of the target party relative to the radar based on the normalized frequency estimate value, the electromagnetic wave wavelength of the radar, and the radar pulse interval.

[0018] In some embodiments of the present application, the calculating of the radial relative motion speed of the target party relative to the radar based on the normalized frequency estimate value, the electromagnetic wave wavelength of the radar, and the radar pulse interval includes:

[0019] Calculating the radial relative motion speed of the target party relative to the radar based on the normalized frequency estimate value, the electromagnetic wave wavelength of the radar, and the radar pulse interval through the following formula;

[0020]

[0021] In the formula, is the radial relative motion speed; λ is the electromagnetic wave wavelength, and T pri is the radar pulse interval; is the estimated value of the normalized frequency.

[0022] In some embodiments of the present application, obtaining the direct path propagation time between the target party and the radar based on the ranging signal includes:

[0023] Uniformly sampling the ranging signal in additive complex Gaussian white noise;

[0024] Filtering the sampled ranging signal through a matched filter of the transmitted signal to obtain an estimated value of the discrete delay of the direct path; the ranging signal received by the radar is the signal formed by the reflection of the transmitted signal by the target party;

[0025] Calculating the direct path propagation time between the target party and the radar based on the estimated value of the discrete delay of the direct path and the radar sampling interval of the radar.

[0026] In some embodiments of the present application, calculating the direct path propagation time between the target party and the radar based on the estimated value of the discrete delay of the direct path and the radar sampling interval of the radar includes:

[0027] Calculating the direct path propagation time between the target party and the radar through the following formula based on the estimated value of the discrete delay of the direct path and the radar sampling interval of the radar;

[0028]

[0029] In the formula, is the direct path propagation time; is the estimated value of the discrete delay of the direct path; T s is the radar sampling interval.

[0030] In some embodiments of the present application, determining the minimum value of the coherence time of the channel between the target party based on the radial relative motion speed includes:

[0031] Determining the minimum value of the coherence time of the channel between the target party through the following formula based on the radial relative motion speed;

[0032]

[0033] In the formula, Tcmin is the minimum coherence time, v c is the speed of light, is the radial relative motion speed, f c is the carrier frequency.

[0034] In some embodiments of the present application, determining the coherence bandwidth of the channel based on the propagation time of the direct path includes:

[0035] Based on the propagation time of the direct path, determining the coherence bandwidth of the channel through the following formula;

[0036]

[0037] In the formula, W c is the coherence bandwidth, is the propagation time of the direct path.

[0038] In some embodiments of the present application, obtaining a detection interval for detecting the channel based on the minimum coherence time and the coherence bandwidth includes:

[0039] Selecting a detection time interval less than or equal to the minimum coherence time, and selecting a detection frequency interval less than or equal to the coherence bandwidth.

[0040] In some embodiments of the present application, after obtaining the detection interval for detecting the channel, it further includes:

[0041] Periodically determining, through the radar, whether the minimum coherence time and the coherence bandwidth have changed;

[0042] In the case where the minimum coherence time and the coherence bandwidth have changed, re-determining the detection interval based on the changed minimum coherence time and coherence bandwidth.

[0043] An embodiment of the second aspect of the present application provides a key generation device based on radar sensing, and the device includes:

[0044] A first acquisition module, configured to receive a speed measurement signal reflected by a target party through a radar, and acquire the radial relative motion speed of the target party relative to the radar based on the speed measurement signal;

[0045] A second acquisition module, configured to receive a ranging signal reflected by the target party through the radar, and acquire the propagation time of the direct path between the target party and the radar based on the ranging signal;

[0046] A determination module, configured to determine a minimum coherence time of a channel between the module and a target party based on the radial relative motion speed; and determine a coherence bandwidth of the channel based on the propagation time of the direct path;

[0047] A detection interval obtaining module, configured to obtain a detection interval for detecting the channel based on the minimum coherence time and the coherence bandwidth;

[0048] A key generation module, configured to generate a symmetric key for communicating with the target party based on the detection interval.

[0049] The technical solution provided in the embodiments of the present application has at least the following technical effects or advantages:

[0050] In the embodiments of the present application, a radar is used to transmit signals for ranging and speed measurement to a target party, and the radar receives the speed measurement signal and the ranging signal reflected by the target party. Based on the received speed measurement signal and ranging signal, the minimum coherence time and the coherence bandwidth are calculated respectively. Furthermore, both communication parties determine the detection interval based on the minimum coherence time and the coherence bandwidth, and both parties detect the channel characteristics based on the same detection interval, ensuring the consistency of the detected channel characteristics, so that the communication parties finally generate the same symmetric key. This method does not rely on a statistical channel model to determine the coherence time and the coherence bandwidth, realizes the direct measurement of the real channel based on the radar, can calculate the coherence time and the coherence bandwidth of the channel in real time, thus can support different communication scenarios, can adapt to the situation of frequent switching of communication scenarios, can modify the detection interval in time with the switching of the communication scenario, so as to realize that after the communication scenario is switched, both communication parties can also update the key in time based on the channel characteristics after the switch, ensuring the security of wireless communication between the communication parties.

[0051] Additional aspects and advantages of the present application will be given in part in the following description, become apparent in part from the following description, or be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] By reading the detailed description of the preferred embodiments below, various other advantages and benefits will become clear to those of ordinary skill in the art. The drawings are only for the purpose of showing the preferred embodiments and are not considered to be a limitation of the present application. Moreover, throughout the drawings, the same reference numerals are used to represent the same components.

[0053] In the drawings:

[0054] Figure 1 Shows a flowchart of a key generation method based on radar perception provided by an embodiment of the present application;

[0055] Figure 2The figure shows a schematic structural diagram of a key generation device based on radar perception provided by an embodiment of the present application;

[0056] Figure 3 The figure shows a schematic structural diagram of an electronic device provided by an embodiment of the present application;

[0057] Figure 4 The figure shows a schematic diagram of a storage medium provided by an embodiment of the present application. Detailed implementation manners

[0058] Hereinafter, the exemplary embodiments of the present application will be described in more detail with reference to the accompanying drawings. Although the exemplary embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided so that the present application can be more thoroughly understood and the scope of the present application can be fully conveyed to those skilled in the art.

[0059] It should be noted that unless otherwise specified, the technical terms or scientific terms used in the present application should have the ordinary meanings understood by those skilled in the art to which the present application belongs.

[0060] In the field of wireless communication, the principle of electromagnetic wave propagation determines the reciprocity of the wireless channel, that is, at the same carrier frequency and the same moment, the impulse responses of the uplink and downlink of the channel are exactly the same. The channel impulse response is a function of time. According to its variation law with time, two concepts, namely, the coherence time and the coherence bandwidth, can be defined. The so-called coherence time refers to the time period during which the channel impulse response can be regarded as constant; and the coherence bandwidth refers to the bandwidth range within which the channel frequency response (the Fourier transform of the channel impulse response) can be regarded as constant.

[0061] By utilizing the reciprocity and time-varying nature of the wireless channel, the two communication parties can generate the same and random keys. To generate keys, channel sounding needs to be carried out first. To ensure that the two communication parties can finally generate the same keys, specific conditions must be met during the sounding process, that is, the time interval between the soundings of the two communication parties needs to be less than the coherence time, and the frequency interval also needs to be less than the coherence bandwidth to ensure the reciprocity of the probed channel.

[0062] However, the prior art has limitations in accurately estimating the coherence time and the coherence bandwidth. Due to the dynamicity and complexity of the wireless environment, including the influence of factors such as multipath propagation and moving speed, it is very difficult to accurately measure these two key parameters. Therefore, in practical applications, it is difficult to ensure the reciprocity of the probed channel, which in turn affects the consistency of the generated keys, posing challenges to the key generation and distribution schemes that rely on the characteristics of the wireless channel.

[0063] The symmetric keys generated and used by both communicating parties are symmetric keys, which play a crucial role in the fields of modern cryptography and information security. It is mainly used for encrypting and decrypting information, capable of transforming sensitive information into ciphertext form. Only the recipient with the same key can decrypt and restore it, ensuring the confidentiality of data during transmission and storage, enabling the two communicating parties to securely exchange data without being eavesdropped or tampered with by a third party. In addition, symmetric keys can also be used to calculate message authentication codes. The recipient can verify whether the message has been tampered with during transmission by verifying this authentication code, so as to verify the integrity of the message and the authenticity of the source, thereby providing data integrity protection and authentication functions.

[0064] In traditional symmetric key generation and distribution mechanisms, it mainly relies on a trusted third-party institution, such as a Certificate Authority (CA). The CA is responsible for generating, managing, and distributing keys. The two communicating parties interact with the CA to obtain and verify the keys. This mechanism has some limitations. For example, it requires complex infrastructure and strict management processes to ensure the security and reliability of the CA. Moreover, in some scenarios, such as resource-constrained Internet of Things devices or complex distributed network environments, it is difficult and costly to implement.

[0065] With the development of technology, physical layer key generation and distribution mechanisms have emerged. This mechanism utilizes the physical characteristics of the wireless channel, such as the reciprocity and randomness of the channel, to directly generate and distribute symmetric keys between the two communicating parties. This method does not require relying on a third-party institution and has higher security and autonomy. During the physical layer key generation process, the two communicating parties detect and measure the wireless channel, extract random characteristics in the channel, such as signal strength, impulse response, frequency response, etc., and transform these characteristics into keys. Due to the reciprocity of the wireless channel characteristics within the coherence time and coherence bandwidth, the two communicating parties can generate highly consistent keys. At the same time, the random time-varying nature of the wireless channel also ensures the unpredictability of the keys, thereby enhancing the security of the keys.

[0066] However, the related technical solutions follow a series of steps during the physical layer key generation and distribution process. First, for a given communication scenario, a statistical channel model is established. This model is based on historical data and theoretical analysis of the channel behavior in this specific environment and can describe the main characteristics of the channel. Next, according to the tap gain autocorrelation function of the statistical channel model, the coherence time and coherence bandwidth of this scenario are calculated. These two parameters are crucial for determining the time and frequency stability of the channel and guide the subsequent selection of the probing interval. After selecting an appropriate probing interval, the system will start to detect the channel characteristics and quantize these characteristics to extract information that can be used for key generation. Furthermore, a symmetric key is generated based on the extracted information.

[0067] Although the solutions of the above related technologies provide a relatively complete key generation process, there are still several significant defects in practical applications:

[0068] 1. The detection interval needs to be modified when switching scenarios: When switching from one scenario to another with different channel characteristics, such as from a stationary environment to a mobile environment, or from an urban area to a rural area, the previously set detection interval may no longer be applicable. At this time, the detection interval needs to be readjusted to adapt to the new channel conditions. Since the above related technologies need to design a statistical channel model based on the communication scenario, a new statistical channel model needs to be recreated when switching scenarios, which not only increases the complexity and maintenance cost of the system, but also may lead to consistency problems in key generation, especially in the case of frequent scenario switching.

[0069] 2. The statistical channel model may not match the communication scenario: Existing statistical channel models are usually constructed based on specific types or a set of typical scenarios, but the real-world wireless environment is extremely diverse and dynamically changing. Therefore, in some special or atypical scenarios, the statistical model used may not accurately describe the actual channel characteristics, resulting in the estimated coherence time and coherence bandwidth not matching the actual situation, and further affecting the consistency of key generation. This mismatch will reduce the quality of the key and increase the risk of being attacked.

[0070] 3. The coherence time and coherence bandwidth are modeled as statistics and may be smaller than the selected detection interval: Since the coherence time and coherence bandwidth are estimated according to statistical distributions, they are not fixed values but have a certain probability distribution. This means that in some cases, the actual coherence time and coherence bandwidth may be much smaller than the selected detection interval. In this case, the change speed of the channel exceeds the range that the detection interval can capture, breaking the assumption of channel stability in the key generation process and reducing the consistency and security of the key.

[0071] 4. The detection interval cannot be modified in real time to adapt to changes in channel parameters: The related technology solutions lack flexibility and cannot automatically adjust the detection interval according to the real-time monitored channel parameters. In a rapidly changing environment, such as a high-speed mobile scenario, the change speed of channel characteristics may exceed the system's ability to update the detection interval, resulting in the key generation process being unable to respond to channel changes in a timely manner, ultimately affecting the quality and consistency of the key. In addition, this static configuration may also cause the system to perform poorly in the face of sudden channel changes, affecting the overall security performance.

[0072] In summary, although the related technology solutions provide a framework for physical layer key generation and distribution, they show obvious limitations when dealing with complex and changing practical application scenarios.

[0073] Based on the above problems existing in the related art, the embodiment of the present application provides a key generation method based on radar perception. This method uses a radar to receive the speed measurement signal reflected by the target party, and obtains the radial relative motion speed of the target party relative to the radar based on the speed measurement signal; uses the radar to receive the ranging signal reflected by the target party, and obtains the direct path propagation time between the target party and the radar based on the ranging signal; determines the minimum coherence time of the channel with the target party based on the radial relative motion speed; and determines the coherence bandwidth of the channel based on the direct path propagation time; obtains the detection interval for detecting the channel based on the minimum coherence time and the coherence bandwidth; and generates a symmetric key for communicating with the target party based on the detection interval.

[0074] This method uses a radar to transmit signals for ranging and speed measurement to the target party, and receives the speed measurement signal and the ranging signal reflected back by the target party through the radar. Based on the received speed measurement signal and ranging signal, the minimum coherence time and the coherence bandwidth are calculated respectively. Then, both communication parties determine the detection interval based on the minimum coherence time and the coherence bandwidth. Both parties detect the channel characteristics based on the same detection interval, ensuring the consistency of the detected channel characteristics, so that the communication parties finally generate the same symmetric key. This method does not rely on a statistical channel model to determine the coherence time and the coherence bandwidth, realizes the direct measurement of the real channel based on the radar, can calculate the coherence time and the coherence bandwidth of the channel in real time, thus can support different communication scenarios, can adapt to the situation of frequent switching of communication scenarios, can modify the detection interval in time with the switching of the communication scenario, so that after the communication scenario is switched, both communication parties can also update the key in time based on the channel characteristics after the switch, ensuring the security of the wireless communication between the communication parties.

[0075] The key generation method provided by the embodiment of the present application can be adapted to any communication scenario, such as a static environment, a mobile environment, a rural environment, an urban environment, a mountainous environment, etc. It can also be adapted to the switching between different communication scenarios, such as switching from a static environment to a mobile environment, switching from a rural environment to an urban environment, etc.

[0076] The key generation method provided by the embodiment of the present application can be applied to any one or both of the wireless communication parties. For the two communication parties, one party can execute the method of the embodiment of the present application to determine the detection interval, and then send the detection interval to the other party. The two communication parties use the same detection interval to detect the channel characteristics, and then generate the same key based on the detected channel characteristics.

[0077] In some other embodiments, the method of the embodiments of the present application can also be executed by both communication parties to determine the detection interval. In such an embodiment, in order to ensure that the detection intervals selected by both communication parties are the same, a strategy for selecting the detection interval can be preconfigured between the two communication parties. As an example, multiple different coherence times and multiple different coherence bandwidths can be set in the strategy, and it is stipulated that after both communication parties automatically calculate the minimum coherence time and the coherence bandwidth in the manner of the embodiments of the present application, a coherence time that is less than the calculated minimum coherence time and has the smallest difference from the calculated minimum coherence time is selected from the multiple coherence times preset in the strategy as the detection time interval. And it is stipulated in the strategy that a coherence bandwidth that is less than the calculated coherence bandwidth and has the smallest difference from the calculated coherence bandwidth is selected from the multiple coherence bandwidths preset in the strategy as the detection frequency interval. After both communication parties execute the method of the embodiments of the present application to calculate the minimum coherence time and the coherence bandwidth in real time, based on the above-mentioned preconfigured strategy, an appropriate detection interval can be automatically selected. Since both communication parties perform real-time measurement and calculation on the same channel, the difference between the minimum coherence time and the coherence bandwidth calculated by both parties is very small and approximately equal. On this basis, if both parties select the detection interval according to the above strategy, it can be ensured that the detection intervals finally selected by both parties are the same. Furthermore, both parties can detect the channel between them based on the same detection interval, and the same key can be generated based on the channel characteristics obtained by the detection.

[0078] In the embodiments of the present application, the two communication parties may include a base station and a mobile terminal, and the mobile terminal may be, but is not limited to, a mobile phone, a tablet computer, a smart watch, smart glasses, etc. The main body that executes the key generation method provided in the embodiments of the present application may be the base station and / or the mobile terminal. The main body for executing this method has a radar function, and may be configured with a radar system independent of the device itself, or may be a case where the device and the radar are integrated. For example, for the base station that executes the method provided in the embodiments of the present application, a radar system independent of the base station may be set, and the radar system is communicatively connected to the base station, and the two jointly implement the method provided in the embodiments of the present application. Or, the radar function is integrated in the base station that executes the method of the embodiments of the present application, and the base station with the radar function can independently implement the method provided in the embodiments of the present application.

[0079] Next, a radar perception-based key generation method and apparatus according to the embodiments of the present application will be described with reference to the accompanying drawings.

[0080] See Figure 1 the flowchart of the radar perception-based key generation method shown, and this method includes the following steps 101-106.

[0081] Step 101: Receive the speed measurement signal reflected by the target party through the radar, and obtain the radial relative motion speed of the target party relative to the radar based on the speed measurement signal.

[0082] Step 102: Receive the ranging signal reflected by the target party through the radar, and obtain the direct path propagation time between the target party and the radar based on the ranging signal.

[0083] Step 103: Determine the minimum coherence time of the channel between the target party based on the radial relative motion speed.

[0084] Step 104: Determine the coherence bandwidth of the channel based on the direct path propagation time.

[0085] Step 105: Obtain the detection interval for detecting the channel based on the minimum coherence time and the coherence bandwidth.

[0086] Step 106: Generate a symmetric key for communicating with the target party based on the detection interval.

[0087] Among them, Step 103 is executed after Step 101, Step 104 is executed after Step 102, Step 101 and Step 102 can be executed synchronously or in any order before and after, and Step 103 and 104 can also be executed synchronously or in any order before and after. In the embodiments of the present application, the serial numbers of the steps are not used to limit the execution order of the steps. Under the condition that the execution logic is reasonable, at least some steps can be executed synchronously or in any order before and after.

[0088] The execution subject of the embodiments of the present application can be any one or both of the two communication parties. For the convenience of description, the embodiments of the present application are described with the execution subject being one of them, and the execution subject is described by taking the base station as an example. In practical applications, the execution subject can be the transmitter and / or receiver of the signal, and both the transmitter and the receiver can be a base station or a mobile terminal, etc.

[0089] In the case where the base station is the execution subject of the embodiments of the present application, the base station is configured with a radar system capable of communicating with the base station, or a radar module is integrated in the base station. The target party mentioned in the embodiments of the present application is the other party that communicates wirelessly with the base station, and the target party can be, but is not limited to, a mobile phone, a tablet computer, a smart wearable device, various sensor devices, etc.

[0090] In the embodiments of the present application, the base station transmits signals for speed measurement and signals for ranging through the radar. These signals reach the target party and are received by the radar after being reflected by the target party. The base station calculates the real-time coherent time and coherent bandwidth based on the received speed measurement signals and ranging signals. Among them, both the speed measurement signal and the ranging signal can be Doppler signals, or the speed measurement signal and the ranging signal can also be pulse radar signals, frequency-modulated continuous-wave radar signals, etc. The speed measurement signal and the ranging signal can be the same signal or different signals.

[0091] Based on the speed measurement signal received by the radar, the base station automatically determines the radial relative motion speed between the base station and the target party, and then uses this radial relative motion speed to calculate the minimum value of the coherent time of the channel between the base station and the target party. In addition, based on the ranging signal received by the radar, the base station automatically determines the direct-path propagation time between the base station and the target party, and then uses this direct-path propagation time to calculate the coherent bandwidth of the channel between the base station and the target party. This method does not rely on a statistical channel model, but is based on the actual measurement of the channel between the base station and the target party by the radar, and calculates the minimum value of the coherent time and the coherent bandwidth in real time. Furthermore, it can select the detection interval based on the automatically calculated minimum value of the coherent time and the coherent bandwidth, detect the channel characteristics based on the detection interval, ensure the consistency of the detected channel characteristics, and enable the two communication parties to finally generate the same symmetric key. Since the minimum value of the coherent time and the coherent bandwidth can be calculated in real time, the detection interval can be adjusted in real time, supporting different communication scenarios, being able to adapt to the situation of frequent switching of communication scenarios, and modifying the detection interval in a timely manner as the communication scenario switches, so as to ensure that the two communication parties can also update the key in a timely manner based on the channel characteristics after the switch after the communication scenario switches, ensuring the security of the wireless communication between the two communication parties.

[0092] In some embodiments of the present application, obtaining the radial relative motion speed of the target party relative to the radar based on the speed measurement signal includes: uniformly sampling the speed measurement signal in additive complex Gaussian white noise; representing the sampled signal in terms of normalized frequency to obtain the speed measurement signal in the normalized frequency domain; performing a discrete Fourier transform on the speed measurement signal in the normalized frequency domain to obtain the transformed speed measurement signal in the frequency domain; obtaining the estimated value of the normalized frequency when the transformed speed measurement signal in the frequency domain takes the maximum amplitude; and calculating the radial relative motion speed of the target party relative to the radar based on the estimated value of the normalized frequency, the electromagnetic wave wavelength of the radar, and the radar pulse interval.

[0093] The above representation of the sampled speed measurement signal in terms of normalized frequency can be specifically represented by the following formula (1):

[0094]

[0095] In the above formula (1), n is the serial number of the discrete speed measurement signal obtained by sampling. r[n] is the representation of the nth speed measurement signal obtained by sampling in the normalized frequency domain, or it can be said to be the speed measurement signal in the nth normalized frequency domain. A is the change in the amplitude and phase of the channel for the received speed measurement signal, and A is a complex number mathematically. j is an imaginary number, f 0 is the normalized frequency, and w[n] is the additive complex Gaussian white noise when the sampling serial number is n.

[0096] Performing a discrete Fourier transform on the above r[n], the transformed speed measurement signal R[f] in the frequency domain is obtained, as shown in formula (2):

[0097]

[0098] In the above formula (2), N is the total number of samples of the speed measurement signal, and f is the frequency.

[0099] In the embodiment of the present application, based on the above formula (2), a preset parameter estimation algorithm is adopted to obtain the estimated value of the normalized frequency when the transformed speed measurement signal in the frequency domain takes the maximum amplitude. Among them, the preset parameter estimation algorithm is used to perform the operation of taking the maximum amplitude on formula (2) to determine the estimated value of the normalized frequency value when R[f] takes the maximum amplitude. The preset parameter estimation algorithm may include but is not limited to the maximum likelihood estimation algorithm, the maximum a posteriori probability estimation algorithm, etc. Specifically, the estimated value of the normalized frequency can be calculated through the following formula (3).

[0100]

[0101] In formula (3), is the estimated value of the normalized frequency, argmax f {|R[f]| 2} represents finding the independent variable f corresponding to the maximum value of the function |R[f]| 2 , where f is the frequency.

[0102] After obtaining the estimated value of the normalized frequency through formula (3) then, the radial relative motion speed of the target with respect to the radar is calculated through the following formula (4).

[0103]

[0104] In formula (4), is the radial relative motion speed; λ is the electromagnetic wave wavelength of the radar, T pri is the radar pulse interval; is the estimated value of the normalized frequency.

[0105] Based on the speed measurement signal received by the radar, through mathematical operations, and using parameter estimation methods such as the maximum likelihood estimation algorithm, the radial relative motion speed is calculated. It realizes real-time calculation of the radial relative motion speed between the target and the radar based on the actual measurement of the true channel between the two parties, making the calculated radial relative motion speed fit the actual situation of the target, and being able to adapt to the scene changes of the relative motion between the target and the radar, such as the relative motion state changing from relative rest to relative motion between the target and the radar. Furthermore, based on the calculated radial relative motion speed, subsequent real-time and accurate calculation of the minimum value of the coherence time of the channel between the two parties can be achieved.

[0106] There is a certain mapping relationship between the radial relative motion speed calculated in the above embodiments and the coherence time of the channel. Before introducing the relationship between the radial relative motion speed and the coherence time of the channel, the discrete-time baseband model of the wireless channel is introduced first.

[0107] Assume that the bandwidth of the input waveform is limited to W, then the baseband equivalent is limited to According to the sampling theorem, the input waveform is:

[0108] x b (t) = ∑ n x[n]sinc(Wt - n) ......(5)

[0110] In formula (5), W is the waveform bandwidth of the signal, t is time, and x b (t) is the waveform of the baseband signal input to the channel at time t; n is the serial number of the discrete signal, and x[n] represents the discrete transmission signal before digital-to-analog conversion.

[0111] Among them, represents the waveform of the baseband signal input to the channel at time.

[0112]

[0113] According to electromagnetic theory and coherent receiver theory, the baseband equivalent channel is:

[0114]

[0115] In formula (6), y b (t) is the waveform of the baseband signal output from the channel at time t, i is the serial number of the electromagnetic wave propagation path, a i is the attenuation of the i-th path, j is the imaginary number, f c is the carrier frequency, τ i is the propagation delay of the i-th path, and w(t) is the Gaussian white noise at time t.

[0116] Substitute the above formula (5) into formula (6) to obtain the following formula (7):

[0117]

[0118] For the meanings of the parameters in formula (7), reference can be made to the meanings of the parameters in the above formulas (5) and (6), which will not be elaborated here.

[0119] Thus, at the sampling output at integer multiples of it can be expressed as:

[0120]

[0121] In formula (8), m is the sampling sequence number of the channel output signal, y[m] represents the waveform of the m-th output signal obtained by sampling the channel output signal, and w[m] represents the Gaussian white noise when sampling the m-th output signal. For the meanings of the other parameters in formula (8), reference can be made to the meanings of the corresponding parameters in the foregoing formulas, which will not be elaborated here.

[0122] The sampled output y[m] in formula (8) can be equivalently regarded as the projection of the waveform y b (t) on the waveform Wsinc(Wt - m). Let l := m - n, then the above formula (8) can be rewritten as the following formula (9):

[0123]

[0124] Define:

[0125]

[0126] Using h l [m] in formula (10) to simplify formula (9), then formula (9) can be written in the simple form shown in the following formula (11):

[0127] y[m] = ∑ l h l [m]x[m - l] + w[m] ......(11)

[0129] Use h l [m] to represent the l-th channel filter tap at time m, and the value of h l [m] is a function of the path gain The propagation delay τ i (t) is close to

[0130] ​The above formulas (5)-(11) give the derivation process of the discrete-time baseband model of the wireless channel. Based on the discrete-time baseband model, the embodiments of the present application study and derive the relationship between the coherence time and the radial relative motion speed.

[0131] Specifically, referring to formula (9), the part that has the greatest influence on the sampled output y[m] on the time scale in formula (9) is And this part is defined as the channel filter tap h l [m] in formula (10). As a function of time m, the time scale of the fluctuation of the channel filter tap h l [m] is a very important channel parameter.

[0132] Next, formula (10) is analyzed in detail. The significant change in the attenuation of the i-th path in formula (10) appears in a cycle of several seconds or even longer. Therefore, the influence on the channel filter tap h l [m] is relatively small. In formula (10), the change of the term caused by the time fluctuation of each is proportional to the bandwidth. So the influence of the l term on the channel filter tap h

[0133]

[0134]

[0135] D i is the Doppler shift of the i-th path, v i (t) is the relative motion speed of the i-th path at time t, and v c is the speed of light.

[0134] When the different paths contributing to the l-th channel filter tap have different Doppler shifts, the amplitude of h l [m] will have a significant change. This phenomenon occurs when the time scale is inversely proportional to the maximum difference between the Doppler shift, that is, when the time scale is inversely proportional to the Doppler spread D s :

[0135]

[0136] In formula (12), both i and j are path numbers, vj (t) is the relative motion speed of the j-th path at time t. Among them, the maximum operation in formula (12) is performed on all paths that make important contributions to the channel filter taps.

[0137] Therefore, due to the phase change, it will cause the fastest change in the filter tap h l [m], and it is very obvious within the delay change The coherence time T of the wireless channel c is defined as the time interval when h l [m] undergoes significant changes (quantitatively):

[0138]

[0139] Let the radial relative motion speed be Then the minimum coherence time is:

[0140]

[0141] In formula (14), T cmin is the minimum coherence time, v c is the speed of light, is the radial relative motion speed, f c is the carrier frequency.

[0142] After calculating the radial relative motion speed through the previous formulas (1)-(4), substituting it into the above formula (14), the minimum coherence time of the channel between the base station and the target can be determined.

[0143] By actually measuring the speed of the real channel between the base station and the target through radar, based on the speed measurement signal, the radial relative motion speed of the target relative to the base station is calculated through parameter estimation methods such as the maximum likelihood estimation algorithm. Based on the mapping relationship between the relative motion speed and the minimum coherence time, the minimum correlation time is calculated. It realizes that without relying on the statistical channel model in related technologies, the minimum coherence time can be obtained through a simple calculation process, improves the matching degree of the calculated minimum coherence time and the communication scenario, and can adapt to different communication scenarios and frequent switching between different communication scenarios.

[0144] After obtaining the minimum coherence time through the above method, the base station can select a sounding time interval less than or equal to the minimum coherence time. To ensure that both communication parties can generate consistent keys under the same channel state, the sounding time interval must be less than or equal to the calculated minimum coherence time. This means that the time difference between each sounding should be short enough so that both communication parties can detect the same channel characteristics. A reasonable selection of the sounding time interval is an important step to ensure key consistency.

[0145] For the determination process of the coherence bandwidth, first, it is necessary to obtain the direct-path propagation time between the target and the radar through step 102, and then determine the coherence bandwidth through step 104.

[0146] The process of obtaining the direct-path propagation time may specifically include: uniformly sampling the ranging signal in additive complex Gaussian white noise; filtering the sampled ranging signal through the matched filter of the transmitted signal to obtain an estimated value of the direct-path discrete delay; the ranging signal received by the radar is the signal formed by the target reflecting the transmitted signal; based on the estimated value of the direct-path discrete delay and the radar sampling interval of the radar, calculate the direct-path propagation time between the target and the radar.

[0147] Specifically, in the additive complex Gaussian white noise w[n], uniformly sample the ranging signal received by the radar.

[0148]

[0149] In formula (15), n 0 is the direct-path discrete delay, n is the serial number of the sampled signal, N is the total number of sampled signals, M is the total number of sampled signals containing the radar signal, and s R is the received signal. z[n] is the waveform of the ranging signal of the nth sample.

[0150] Pass z[n] through the matched filter of the transmitted signal s T to obtain an estimated value of the direct-path discrete delay n 0 as: is:

[0151]

[0152] In formula (16), * represents is the conjugate complex number of s T [n - n 0 .

[0153] The embodiment of the present application uses a preset parameter estimation algorithm to estimate the direct-path propagation time. Among them, the preset parameter estimation algorithm is used to perform a maximum value operation on in formula (16) to Determine the estimated value of the direct-path discrete time delay when taking the maximum value The preset parameter estimation algorithm may include, but is not limited to, the maximum likelihood estimation algorithm, the maximum a posteriori probability estimation algorithm, etc.

[0154] Let T s be the radar sampling interval, then the propagation time of the direct path is:

[0155]

[0156] Based on the ranging signal received by the radar in the above embodiment, through mathematical operations, using parameter estimation methods such as the maximum likelihood estimation algorithm, the estimated value of the direct-path discrete time delay is calculated, and then based on the estimated value of the direct-path discrete time delay, the propagation time of the direct path is calculated. It realizes real-time calculation of the propagation time of the direct path between the target party and the radar based on the actual measurement of the real channel between the target party and the radar, making the calculated propagation time of the direct path fit the actual situation and being able to adapt to the change of the communication scenario between the target party and the radar. Furthermore, based on the calculated propagation time of the direct path, subsequent real-time and accurate calculation of the coherence bandwidth of the channel between the target party and the radar can be realized.

[0157] There is a certain mapping relationship between the propagation time of the direct path calculated in the above embodiment and the coherence bandwidth of the channel. The specific derivation process of this mapping relationship is as follows:

[0158] The multipath delay spread T d is defined as the difference between the propagation times of the longest path and the shortest path. The paths mentioned here only include the paths that propagate the main energy. Therefore,

[0159] T d :=max i,j |τ i (t)-τ j (t)|......(18)

[0160] The multipath delay spread T d is defined as a function of time t, but it is a quantitative relationship similar to time coherence and Doppler spread. If the range of a cell or a local area network is several kilometers or smaller, the difference in the lengths of its different paths is very likely to be 300m - 600m, which corresponds to a path delay of 1μs - 2μs. As the cell utilization rate increases, the cell coverage range becomes smaller and smaller, and T d will also become smaller.

[0161] The delay spread of a channel controls its frequency coherence. The wireless channel is constantly changing with respect to both time and frequency. Temporal coherence indicates how fast the channel changes over time, and similarly, frequency coherence indicates how fast the channel changes over frequency.

[0162] The impulse response h(τ,t) of a fading multipath channel is:

[0163] h(τ,t) = ∑ i a i (t)δ(t - τ i (t)) ......(19)

[0165] In formula (19), τ is the propagation delay, t is time, a i (t) is the attenuation of the i-th path at time t, τ i (t) is the propagation delay of the i-th path at time t, and δ() is the unit impulse function, also called the Dirac function.

[0166] Define the time-varying frequency response H(f,t) as:

[0167]

[0168] The phase of the contribution of a specific path is linear with respect to the frequency f. For multiple paths, there is a differential phase 2πf(τ i (t) - τ j (t)), where both i and j are the sequence numbers of the paths. This differential phase causes frequency-selective fading. That is to say, the signal changes significantly not only when time t changes but also when c frequency f changes.

[0169]

[0170] The direct path is the path that the signal passes through when it travels directly from the transmitter to the receiver, and there is no refraction or reflection of the signal in this path. The direct path is the shortest path, and the delays of other paths fluctuate around the delay of the direct path as a reference. Therefore, the delay spread is usually of the same order of magnitude as the propagation time of the direct path. Let the propagation time of the direct path be Then the coherence bandwidth is approximately:

[0171]

[0172] In the formula (22) above, W c is the coherence bandwidth, is the propagation time of the direct path.

[0173] The propagation time of the direct path is calculated through the above formulas (15)-(17). After that, it is substituted into the above formula (22) to calculate the coherence bandwidth of the channel between the base station and the target party.

[0174] The actual ranging of the real channel between the base station and the target party is carried out by radar. Based on the ranging signal, the propagation time of the direct path of the target party relative to the base station is calculated through parameter estimation methods such as the maximum likelihood estimation algorithm. Based on the mapping relationship between the propagation time of the direct path and the coherence bandwidth, the coherence bandwidth is calculated. It is realized that without relying on the statistical channel model in the related technology, the coherence bandwidth can be obtained through a simple calculation process, improving the matching degree between the calculated coherence bandwidth and the communication scenario, and being able to adapt to different communication scenarios and frequent switching between different communication scenarios.

[0175] After obtaining the coherence bandwidth through the above method, a detection frequency interval less than or equal to the coherence bandwidth is selected. To ensure consistent channel responses at different frequencies, the detection frequency interval should be less than or equal to the coherence bandwidth. This is because if the frequency interval is too large, it may span multiple independent fading regions, resulting in inconsistent channel responses at different frequencies. Therefore, selecting an appropriate detection frequency interval can ensure that similar channel state information is obtained at each frequency point, which helps to improve the accuracy of the subsequent generated key.

[0176] The detection interval obtained in step 105 includes the detection time interval and the detection frequency interval obtained through the above implementation manner. Based on this detection time interval and detection frequency interval, the detection of channel characteristics is started, that is, the channel state information is collected, including but not limited to key parameters such as channel gain, phase, and delay. This information will be used as the basic data for subsequent processing to generate keys. Based on the detection time interval and the detection frequency interval, the required channel characteristics can be efficiently collected without affecting normal communication.

[0177] After the channel characteristics are detected, these characteristics are quantized. The quantization process aims to convert the continuous channel state information into a discrete form for further information processing and key generation. Usually, a certain algorithm is adopted to determine the quantization levels while minimizing the quantization error to ensure the high quality of the finally generated key. In addition, the noise and other interference factors that may occur during the quantization process need to be processed to enhance the robustness of the system. After the feature quantization is completed, the information negotiation stage is entered. During this process, the two communication parties exchange some of the quantized channel feature information to reach a consistent key. The purpose of information negotiation is to ensure that even if there are slight differences in channel characteristics, the two parties can still generate the same key. This usually involves a series of protocols and technologies, such as low-density parity-check codes, polar codes, etc., to improve the negotiation efficiency and accuracy while protecting the information security during the negotiation process.

[0178] After generating the key in the above manner, privacy amplification can also be performed on the key to further enhance the security of the key and reduce any potential information leakage risk. Privacy amplification improves the unpredictability and confidentiality of the key by reducing the key length and removing the parts that may be inferred by a third party. This process is an essential part of the physical-layer key generation and distribution mechanism, ensuring the security and uniqueness of the final key and providing a solid security guarantee for communication.

[0179] After generating the key in the above manner, the key can be used to encrypt or decrypt data during the communication with the target party. In the embodiment of this application, after the key is generated, the key is not immutable. The minimum coherence time and the coherence bandwidth can also be periodically determined through radar; in the case where the minimum coherence time and the coherence bandwidth change, based on the changed minimum coherence time and coherence bandwidth, the detection interval is re-determined, and then a new key is regenerated.

[0180] Among them, the process of determining whether the minimum coherence time and the coherence bandwidth have changed is to recalculate the minimum coherence time and the coherence bandwidth through the operations of steps 101-104 and compare the recalculated values with the previously calculated minimum coherence time and coherence bandwidth to determine whether a change has occurred.

[0181] Periodically detecting whether the minimum coherence time and the coherence bandwidth have changed in the above manner is equivalent to periodically determining whether the communication scenario has changed. In the case where the communication scenario has changed, a key adapted to the new communication scenario is regenerated in the manner of steps 101-106, realizing the real-time adjustment of the detection interval and the symmetric key, and being able to adapt to the switching of different communication scenarios.

[0182] The key generation method provided by the embodiments of the present application can be applied to any communication scenario with a direct path between two communication parties and supports frequent communication scenario switching. For a communication scenario without a direct path, the method in the related art can be first used to create a statistical channel model for the communication scenario without a direct path, and a symmetric key for the communication scenario without a direct path is generated based on the statistical channel model. The symmetric key is pre-configured in the devices of the two communication parties. When the two communication parties are in the communication scenario without a direct path, communication is carried out using the preset symmetric key, and it is detected in real time whether the communication scenario has switched. When it is detected that the communication scenario has switched, the method provided by the embodiments of the present application is executed to generate a symmetric key adapted to the current communication scenario in real time.

[0183] In the embodiments of the present application, a radar is used to transmit signals for ranging and speed measurement to the target party, and the radar receives the speed measurement signal and the ranging signal reflected by the target party. Based on the received speed measurement signal and ranging signal, the minimum coherence time and the coherence bandwidth are respectively calculated. Furthermore, the two communication parties determine the detection interval based on the minimum coherence time and the coherence bandwidth, and the two parties detect the channel characteristics based on the same detection interval, ensuring the consistency of the detected channel characteristics, so that the two communication parties finally generate the same symmetric key. This method does not rely on a statistical channel model to determine the coherence time and the coherence bandwidth, realizes the direct measurement of the real channel based on the radar, can perform real-time calculation of the coherence time and the coherence bandwidth of the channel, thus can support different communication scenarios, can adapt to the situation of frequent communication scenario switching, and can modify the detection interval in time as the communication scenario switches, so as to realize that after the communication scenario switches, the two communication parties can also update the key in time based on the channel characteristics after the switch, ensuring the security of wireless communication between the two communication parties.

[0184] The embodiments of the present application also provide a key generation device based on radar perception, and this device is used to execute the key generation method based on radar perception provided by any of the above embodiments. Refer to Figure 2 , this device includes:

[0185] The first acquisition module 201 is used to receive the speed measurement signal reflected by the target party through the radar and obtain the radial relative motion speed of the target party relative to the radar based on the speed measurement signal;

[0186] The second acquisition module 202 is used to receive the ranging signal reflected by the target party through the radar and obtain the propagation time of the direct path between the target party and the radar based on the ranging signal;

[0187] The determination module 203 is used to determine the minimum coherence time of the channel with the target party based on the radial relative motion speed; and determine the coherence bandwidth of the channel based on the propagation time of the direct path;

[0188] A detection interval obtaining module 204, configured to obtain a detection interval for detecting a channel based on a minimum coherence time and a coherence bandwidth;

[0189] A secret key generation module 205, configured to generate a symmetric key for communicating with a target party based on the detection interval.

[0190] A first acquisition module 201, configured to uniformly sample a speed measurement signal in additive complex Gaussian white noise; represent the sampled signal using a normalized frequency to obtain a speed measurement signal in the normalized frequency domain; perform a discrete Fourier transform on the speed measurement signal in the normalized frequency domain to obtain a speed measurement signal after transformation in the frequency domain; obtain a normalized frequency estimation value when the speed measurement signal after transformation in the frequency domain takes the maximum amplitude; calculate a radial relative motion speed of the target party relative to the radar based on the normalized frequency estimation value, the electromagnetic wave wavelength of the radar, and the radar pulse interval.

[0191] The first acquisition module 201 is configured to calculate a radial relative motion speed of the target party relative to the radar based on the normalized frequency estimation value, the electromagnetic wave wavelength of the radar, and the radar pulse interval through the following formula;

[0192]

[0193] In the formula, is the radial relative motion speed; λ is the electromagnetic wave wavelength, T pri is the radar pulse interval; is the normalized frequency estimation value.

[0194] A second acquisition module 202, configured to uniformly sample a ranging signal in additive complex Gaussian white noise; filter the sampled ranging signal through a matched filter of the transmitted signal to obtain an estimated value of the direct path discrete delay; the ranging signal received by the radar is a signal formed by the target party reflecting the transmitted signal; calculate a direct path propagation time between the target party and the radar based on the estimated value of the direct path discrete delay and the radar sampling interval of the radar.

[0195] The second acquisition module 202 is configured to calculate a direct path propagation time between the target party and the radar based on the estimated value of the direct path discrete delay and the radar sampling interval of the radar through the following formula;

[0196]

[0197] In the formula, is the direct path propagation time; is the estimated value of the direct path discrete delay; T s is the radar sampling interval.

[0198] A determination module 203, configured to determine a minimum coherence time of a channel with a target party based on a radial relative motion speed through the following formula;

[0199]

[0200] In the formula, T cmin is the minimum coherence time, v c is the speed of light, is the radial relative motion speed, f c is the carrier frequency.

[0201] A determination module 203, configured to determine a coherence bandwidth of a channel based on a direct-path propagation time through the following formula;

[0202]

[0203] In the formula, W c is the coherence bandwidth, is the direct-path propagation time.

[0204] A detection interval acquisition module 204, configured to select a detection time interval less than or equal to the minimum coherence time, and select a detection frequency interval less than or equal to the coherence bandwidth.

[0205] The apparatus further includes: an adjustment module, configured to periodically determine, through a radar, whether the minimum coherence time and the coherence bandwidth change; and in the case where the minimum coherence time and the coherence bandwidth change, re-determine a detection interval based on the changed minimum coherence time and coherence bandwidth.

[0206] The key generation apparatus based on radar sensing provided in the foregoing embodiments of the present application and the key generation method based on radar sensing provided in the embodiments of the present application are based on the same inventive concept, and have the same beneficial effects as the methods adopted, run, or implemented by the application programs stored therein.

[0207] The embodiments of the present application further provide an electronic device to execute the foregoing key generation method based on radar sensing. Please refer to Figure 3 , which shows a schematic diagram of an electronic device provided in some embodiments of the present application. As Figure 3 shown, the electronic device 10 includes: a processor 1000, a memory 1001, a bus 1002, and a communication interface 1003. The processor 1000, the communication interface 1003, and the memory 1001 are connected through the bus 1002; a computer program that can run on the processor 1000 is stored in the memory 1001, and when the processor 1000 runs the computer program, it executes the method provided in any of the foregoing embodiments of the present application.

[0208] Among them, the memory 1001 may include high-speed random access memory (RAM), and may also include non-volatile memory, such as at least one disk memory. The communication connection between this system network element and at least one other network element is realized through at least one communication interface 1003 (which can be wired or wireless), and the Internet, wide area network, local area network, metropolitan area network, etc. can be used.

[0209] The bus 1002 can be an ISA bus, a PCI bus, an EISA bus, etc. The bus can be divided into an address bus, a data bus, a control bus, etc. Among them, the memory 1001 is used to store programs. After receiving an execution instruction, the processor 1000 executes the program. Any implementation manner of the method disclosed in any embodiment of the present application can be applied to the processor 1000 or implemented by the processor 1000.

[0210] The processor 1000 may be an integrated circuit chip with signal processing capabilities. In the implementation process, each step of the above method can be completed by the integrated logic circuit in the hardware of the processor 1000 or the instructions in the form of software. The above-mentioned processor 1000 can be a general-purpose processor, including a central processing unit (CPU for short), a network processor (NP for short), etc.; it can also be a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components. It can implement or execute the various methods, steps and logic block diagrams disclosed in the embodiments of the present application. The general-purpose processor can be a microprocessor or the processor can also be any conventional processor, etc. The steps of the method disclosed in combination with the embodiments of the present application can be directly embodied as being executed and completed by the hardware decoding processor, or executed and completed by the combination of the hardware and software modules in the decoding processor. The software module can be located in a mature storage medium in the art such as random access memory, flash memory, read-only memory, programmable read-only memory or electrically erasable programmable memory, registers, etc. This storage medium is located in the memory 1001, and the processor 1000 reads the information in the memory 1001 and combines its hardware to complete the steps of the above method.

[0211] The electronic device provided by the embodiment of the present application and the key generation method based on radar perception provided by the embodiment of the present application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run or implemented by it.

[0212] The embodiments of the present application also provide a computer-readable storage medium corresponding to the radar perception-based key generation method provided in the foregoing embodiments. Please refer to Figure 4 , which shows that the computer-readable storage medium is an optical disc 30, on which a computer program (i.e., a program product) is stored. When the computer program is run by a processor, it will execute the methods provided in any of the foregoing embodiments.

[0213] It should be noted that examples of the computer-readable storage medium may also include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory, or other optical and magnetic storage media, which will not be elaborated here one by one.

[0214] The computer-readable storage medium provided in the above embodiments of the present application and the radar perception-based key generation method provided in the embodiments of the present application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run, or implemented by the application programs stored therein.

[0215] The embodiments of the present application also provide a computer program product corresponding to the radar perception-based key generation method provided in the foregoing embodiments. The computer program product includes a computer program, and the computer program is executed by a processor to implement the methods provided in the foregoing embodiments.

[0216] The computer program product provided in the above embodiments of the present application and the radar perception-based key generation method provided in the embodiments of the present application are based on the same inventive concept and have the same beneficial effects as the methods adopted, run, or implemented by the application programs stored therein.

[0217] It should be noted that:

[0218] In the specification provided herein, a large number of specific details are described. However, it can be understood that the embodiments of the present application can be practiced without these specific details. In some instances, well-known structures and technologies are not shown in detail so as not to obscure the understanding of this specification.

[0219] Similarly, it should be understood that, for the purpose of streamlining the present application and facilitating the understanding of one or more of the various inventive aspects, in the foregoing description of the exemplary embodiments of the present application, the various features of the present application are sometimes grouped together into a single embodiment, figure, or description thereof. However, the disclosed method should not be construed as reflecting an intention that the claimed subject matter of the present application requires more features than are expressly recited in each claim. Rather, as reflected in the following claims, the inventive aspects lie in less than all the features of the single foregoing disclosed embodiment. Thus, the claims following the detailed description are hereby expressly incorporated into the detailed description, with each claim standing on its own as a separate embodiment of the present application.

[0220] In addition, those skilled in the art will appreciate that although some of the embodiments described herein include certain features included in other embodiments but not others, combinations of features of different embodiments are meant to be within the scope of the present application and form different embodiments. For example, in the following claims, any one of the claimed embodiments can be used in any combination.

[0221] As described above, the foregoing are only the preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present application should be covered by the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims

1. A key generation method based on radar perception, characterized in that: The method comprises: Receiving a speed measurement signal reflected by a target through a radar, and obtaining a radial relative motion speed of the target relative to the radar based on the speed measurement signal; receiving, by the radar, a ranging signal reflected by the target, and acquiring a direct path propagation time between the target and the radar based on the ranging signal; Determine the minimum coherence time of the channel with the target party based on the radial relative motion speed; and determine the coherence bandwidth of the channel based on the direct path propagation time; Based on the minimum coherence time and the coherence bandwidth, obtaining a detection interval for detecting the channel; Based on the probing interval, a symmetric key for communicating with the target party is generated.

2. The method according to claim 1, characterized in that The obtaining the radial relative motion speed of the target relative to the radar based on the speed measurement signal includes: uniformly sampling the speed measurement signal in additive complex Gaussian white noise; The sampled signal is represented by a normalized frequency to obtain a speed measurement signal in a normalized frequency domain; Performing discrete Fourier transform on the speed measurement signal in the normalized frequency domain to obtain a speed measurement signal after frequency domain down-transformation; Obtaining a normalized frequency estimation value when the speed measurement signal after the frequency domain down-conversion takes the maximum amplitude; The radial relative motion speed of the target relative to the radar is calculated based on the normalized frequency estimation value, the electromagnetic wave wavelength of the radar and the radar pulse interval.

3. The method according to claim 2, characterized in that The calculating the radial relative motion speed of the target relative to the radar based on the normalized frequency estimation value, the electromagnetic wave wavelength of the radar and the radar pulse interval comprises: Based on the normalized frequency estimation value, the electromagnetic wave wavelength of the radar and the radar pulse interval, the radial relative motion speed of the target relative to the radar is calculated by the following formula; In the formula, is the radial relative motion speed; λ is the wavelength of the electromagnetic wave, T pri is the radar pulse interval; is the normalized frequency estimate.

4. The method according to claim 1, characterized in that The acquiring the direct path propagation time between the target and the radar based on the ranging signal comprises: uniformly sampling the ranging signal in additive complex Gaussian white noise; The sampled ranging signal is filtered by a matched filter of the transmitted signal to obtain an estimated value of the discrete time delay of the direct path; the ranging signal received by the radar is a signal formed by the target reflecting the transmitted signal; The direct path propagation time between the target and the radar is calculated based on the estimated value of the direct path discrete time delay and the radar sampling interval of the radar.

5. The method according to claim 4, characterized in that The calculating the direct path propagation time between the target and the radar based on the estimated value of the direct path discrete time delay and the radar sampling interval of the radar includes: Based on the estimated value of the direct path discrete delay and the radar sampling interval of the radar, the direct path propagation time between the target and the radar is calculated by the following formula; In the formula, is the direct path propagation time; is the estimated value of the discrete delay of the direct path; T s is the radar sampling interval.

6. The method according to claim 1, characterized in that The determining, based on the radial relative motion speed, a minimum coherence time of a channel with the target party includes: Based on the radial relative motion speed, determining the minimum coherence time of the channel between the target party and the target party by the following formula; In the above formula, T cmin is the minimum coherence time, v c is the speed of light, is the radial relative motion speed, f c is the carrier frequency.

7. The method according to claim 1, characterized in that The determining the coherence bandwidth of the channel based on the direct path propagation time comprises: Based on the direct path propagation time, the coherence bandwidth of the channel is determined by the following formula; In the above formula, W c is the coherence bandwidth, is the direct path propagation time.

8. The method according to claim 1, characterized in that The obtaining, based on the minimum coherence time and the coherence bandwidth, a detection interval for detecting the channel comprises: A detection time interval is selected that is smaller than or equal to the minimum coherence time, and a detection frequency interval is selected that is smaller than or equal to the coherence bandwidth.

9. The method according to any one of claims 1 to 8, characterized in that: After obtaining the detection interval for detecting the channel, the method further includes: periodically passing through the radar to determine whether the minimum coherence time and the coherence bandwidth change; In the case where the minimum coherence time and the coherence bandwidth change, the detection interval is re-determined based on the changed minimum coherence time and the coherence bandwidth.

10. A key generation device based on radar perception, characterized in that: The device comprises: A first acquisition module is used to receive a speed measurement signal reflected by a target through a radar, and obtain a radial relative motion speed of the target relative to the radar based on the speed measurement signal; A second acquisition module is used to receive the ranging signal reflected by the target through the radar, and acquire the direct path propagation time between the target and the radar based on the ranging signal; A determination module, configured to determine a minimum coherence time of a channel with the target party based on the radial relative motion speed; and to determine a coherence bandwidth of the channel based on the direct path propagation time; A detection interval obtaining module, used for obtaining a detection interval for detecting the channel based on the minimum coherence time and the coherence bandwidth; A key generation module is used to generate a symmetric key for communicating with the target party based on the detection interval.

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