Physical side link broadcast channel radio frequency fingerprint extraction method based on cyclic cross-power spectrum quotient characteristics

Abstract

The invention discloses a physical side link broadcast channel radio frequency fingerprint extraction method based on cyclic cross-power spectrum quotient characteristics, which comprises the following steps: a receiver receives a PSBCH sent by an LTE-V2X terminal, converts the PSBCH into a baseband signal, extracts effective subcarriers of two PSSSs, three DMRSs and two SSSSs in the baseband signal to obtain an effective subcarrier sequence, and sends the effective subcarrier sequence to the LTE-V2X terminal; obtaining a subcarrier sequence at the center position of the three DMRS effective subcarrier sequences; calculating the cyclic cross-power spectrum density of the effective subcarrier sequence to obtain a cyclic cross-power spectrum quotient; and processing the cyclic cross-power spectrum quotient to obtain the radio frequency fingerprint of the PSBCH. According to the method, the influence of channel interference and noise can be effectively eliminated, the accuracy and reliability of radio frequency fingerprints are greatly improved, the radio frequency circuit characteristics of terminal equipment are reflected more truly, the false identification rate and rejection rate are reduced, and more reliable guarantee is provided for the communication security of the Internet of Vehicles.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless communication device identity recognition and information security, and in particular to a method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross power spectrum quotient characteristics. Background Art

[0002] Amid the rapid development of intelligent transportation systems, connected vehicle (IoV) technology, with its ability to enable efficient communication between vehicles and between vehicles and infrastructure, has become a key technology for improving traffic safety and optimizing traffic flow. LTE-V2X, with its low-latency and highly reliable communication advantages, has become a mainstream communication standard in the IoV field. However, as IoV application scenarios continue to expand, communication security issues are becoming increasingly prominent. Reliable authentication of vehicle terminal devices has become a core challenge in ensuring IoV information security.

[0003] Radio frequency fingerprinting technology, as a device identification method based on physical layer characteristics, uniquely identifies devices by extracting unique features of their RF circuits due to manufacturing process variations, providing a new solution for connected vehicle security authentication. Traditional RF fingerprinting methods primarily rely on signal characteristics in the time, frequency, or time-frequency domains, directly analyzing parameters such as the amplitude and phase of the received signal to extract fingerprint features. However, in the complex communication environment of connected vehicles, these methods face numerous challenges. First, connected vehicle communication signals are susceptible to channel interference such as multipath and Doppler shift, as well as ambient noise. This results in significant fluctuations and errors in the extracted RF fingerprint features, making it difficult to accurately reflect the device's true physical characteristics. Second, the LTE-V2X Physical Sidelink Broadcast Channel Signal (PSBCH) contains multiple synchronization signals and demodulation reference signals. Traditional methods are unable to effectively separate features related to the device's RF circuit characteristics from these signals, resulting in the extracted RF fingerprint containing a significant amount of channel interference and noise, reducing the accuracy and reliability of device authentication. Therefore, there is an urgent need for a method that can adapt to the complex communication environment of the Internet of Vehicles, effectively remove channel interference and noise influences, and accurately extract the radio frequency fingerprint of LTE-V2X terminal devices, so as to meet the urgent demand for high-precision and high-reliability device identity recognition technology for Internet of Vehicles security authentication. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross-power spectrum quotient characteristics, which effectively eliminates channel disturbances and noise interference, accurately obtains the radio frequency fingerprints of terminal devices, improves the accuracy and security of device identity recognition in the Internet of Vehicles environment, and provides reliable technical guarantees for the security of Internet of Vehicles communications.

[0005] The present invention adopts the following technical solution: a method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross power spectrum quotient characteristics, comprising the following steps:

[0006] S1. The receiver receives the PSBCH sent by the LTE-V2X terminal, converts it into a baseband signal, extracts the effective subcarriers of two PSSS (Primary Sidelink Synchronization Signal), three DMRS (Demodulation Reference Signal) and two SSSS (Secondary Sidelink Synchronization Signal) in the baseband signal, and obtains the effective subcarrier sequence.

[0007] S2. Extract the correlation sequences at the center positions of the three DMRS effective subcarrier sequences respectively to obtain the subcarrier sequences at the center positions of the three DMRS effective subcarrier sequences.

[0008] S3. Calculate the cyclic cross-power spectral density of the two PSSS effective subcarrier sequences to obtain a first cyclic cross-power spectral density; calculate the cyclic cross-power spectral density of the subcarrier-related sequences at the center positions of the effective subcarrier sequences of the first and second DMRSs to obtain a second cyclic cross-power spectral density; calculate the cyclic cross-power spectral density of the subcarrier-related sequences at the center positions of the effective subcarrier sequences of the second and third DMRSs to obtain a third cyclic cross-power spectral density; calculate the cyclic cross-power spectral density of the two SSSS effective subcarrier sequences to obtain a fourth cyclic cross-power spectral density.

[0009] S4. Obtain a first cyclic cross-power spectrum quotient based on the first cyclic cross-power spectrum density and the second cyclic cross-power spectrum density; and obtain a second cyclic cross-power spectrum quotient based on the third cyclic cross-power spectrum density and the fourth cyclic cross-power spectrum density.

[0010] S5. Concatenate the first cyclic cross-power spectrum quotient and the second cyclic cross-power spectrum quotient to obtain a radio frequency fingerprint of the PSBCH.

[0011] Furthermore, in step S1, the effective subcarrier sequence Y of the first and second PSSS PSSS1 、Y PSSS2 Each includes 62 effective subcarriers, and the effective subcarrier sequence Y of the first, second and third DMRS DMRS1 、Y DMRS2 、Y DMRS3 Each includes 72 effective subcarriers, and the effective subcarrier sequence Y of the first and second SSSS SSSS1 、Y SSSS2Both include 62 effective subcarriers.

[0012] Furthermore, in step S2, 62 effective subcarriers at the center positions of the three DMRS effective subcarrier sequences are extracted respectively to obtain the effective subcarrier sequence at the center position of the DMRS. The specific expression is:

[0013]

[0014] in, Indicates the subcarrier sequence at the center position of the u-th DMRS effective subcarrier sequence, Y DMRSu Indicates the u-th DMRS effective subcarrier sequence, startpoint indicates the starting point of the 62 subcarriers at the center; endpoint indicates the ending point of the 62 subcarriers at the center.

[0015] Furthermore, in step S3, the calculation formula of the cyclic cross power spectrum density is:

[0016] P PSSS =Y PSSS1 ·Y * PSSS2

[0017]

[0018]

[0019] P SSSS =Y SSSS1 ·Y * SSSS2

[0020] Among them, P PSSS represents the first cycle cross power spectrum density, · represents the dot product operation, * represents the conjugate, P DMRS1 represents the second cyclic cross-power spectral density, Indicates the subcarrier sequence at the center of the first DMRS effective subcarrier sequence, Indicates the subcarrier sequence at the center of the second DMRS effective subcarrier sequence, P DMRS2 represents the third cyclic cross-power spectral density, Indicates the subcarrier sequence at the center of the third DMRS effective subcarrier sequence, P SSSS represents the fourth cyclic cross-power spectral density.

[0021] Furthermore, in step S4, the calculation formula of the cyclic cross power spectrum quotient is:

[0022]

[0023] Among them, PQ (PSSS,DMRS1)represents the first cyclic cross-power quotient, PQ (SSSS,DMRS2) represents the second cyclic cross-power spectrum quotient, represents the first channel cyclic power spectrum, P PSSS_RFF represents the cyclic cross power spectrum of PSSS including RF fingerprint features, P DMRS1_RFF P represents the cyclic cross power spectrum of the first and second DMRS containing the radio frequency fingerprint feature, H2 represents the second channel cyclic power spectrum, P SSSS_RFF represents the cyclic cross power spectrum of SSSS containing RF fingerprint features, P DMRS2_RFF Indicates the cyclic cross power spectrum of the second and third DMRSs containing the radio frequency fingerprint feature.

[0024] Furthermore, in step S5, the calculation formula of the radio frequency fingerprint of PSBCH is:

[0025] PQ=concat(PQ (PSSS,DMRS1) ,PQ (SSSS,DMRS2) )

[0026] Among them, PQ represents the radio frequency fingerprint of PSBCH.

[0027] Furthermore, the present invention also proposes an electronic device, comprising a memory, a processor, and a computer program stored in the memory and runnable on the processor. When the processor executes the computer program, the steps of the method for extracting the radio frequency fingerprint of the physical side link broadcast channel based on the cyclic cross power spectrum quotient feature are implemented.

[0028] Furthermore, the present invention also proposes a computer-readable storage medium, which stores a computer program. When the computer program is run by a processor, it executes the physical side link broadcast channel radio frequency fingerprint extraction method based on the cyclic cross power spectrum quotient feature.

[0029] Compared with the prior art, the present invention adopts the above technical solution and has the following technical effects:

[0030] The present invention obtains effective subcarriers of specific signals in the PSBCH signal (two primary-side link synchronization signals, three demodulation reference signals, and two secondary-side link synchronization signals), accurately selects the middle 62 subcarriers of the demodulation reference signal, and effectively eliminates the influence of channel interference and noise by dividing the cyclic cross-power spectrum density. The LTE-V2X terminal radio frequency fingerprint that does not contain channel interference and noise is obtained, which greatly improves the accuracy and reliability of the radio frequency fingerprint, more realistically reflects the radio frequency circuit characteristics of the terminal equipment, reduces the false recognition rate and rejection rate, and provides a more reliable guarantee for the communication security of the Internet of Vehicles. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1It is an overall implementation flow chart of the present invention.

[0032] Figure 2 This is a format diagram of a subframe of a physical side link broadcast channel in an embodiment of the present invention.

[0033] Figure 3 1 is an amplitude diagram and a phase diagram of an effective subcarrier sequence in an embodiment of the present invention.

[0034] Figure 4 1 and 2 are amplitude and phase diagrams of the cyclic cross power spectrum density splicing in an embodiment of the present invention.

[0035] Figure 5 These are amplitude and phase diagrams of radio frequency fingerprints of physical side link broadcast channels of different devices in an embodiment of the present invention. DETAILED DESCRIPTION

[0036] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention.

[0037] To achieve the above objectives, the present invention proposes a method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross power spectrum quotient characteristics, such as Figure 1 The specific steps are as follows:

[0038] S1. The receiver receives the PSBCH (Physical Sidelink Broadcast Channel Signal) sent by the LTE-V2X terminal, converts it into a baseband signal, extracts the effective subcarriers of two PSSS (Primary Sidelink Synchronization Signal), three DMRS (Demodulation Reference Signal) and two SSSS (Secondary Sidelink Synchronization Signal) from the baseband signal, and obtains the effective subcarrier sequence.

[0039] Among them, the effective subcarrier sequence Y of the first and second PSSS PSSS1 、Y PSSS2 Each includes 62 effective subcarriers, and the effective subcarrier sequence Y of the first, second and third DMRS DMRS1 、Y DMRS2 、Y DMRS3 Each includes 72 effective subcarriers, and the effective subcarrier sequence Y of the first and second SSSS SSSS1 、Y SSSS2 Both include 62 effective subcarriers.

[0040] The format of a PSBCH subframe is as follows Figure 2 As shown in the figure, you can see the positions of PSSS, SSSS, and DMRS in a subframe. DMRS occupies 72 subcarriers in the center of the sidecarrier, while PSSS and SSSS each occupy 62 subcarriers in the center of the sidecarrier.

[0041] Figure 3 (a) is the amplitude diagram of the first PSSS effective subcarrier sequence of device 1 for 10 frames, Figure 3 (b) is the phase diagram of the first PSSS effective subcarrier sequence of device 1 for 10 frames, Figure 3 (c) is the amplitude diagram of the first DMRS effective subcarrier sequence of device 1 for 10 frames, Figure 3 (d) is the phase diagram of the first DMRS effective subcarrier sequence of device 1 for 10 frames, Figure 3 (e) is the amplitude diagram of the first SSSS effective subcarrier sequence of device 1 for 10 frames, Figure 3 Figure (f) shows the phase diagram of the first SSSS effective subcarrier sequence for device 1 over 10 frames. The figure shows that when the vehicle is traveling at 10-30 km / h, the PSSS, SSSS, and DMRS signals are severely affected by noise and the channel, resulting in chaotic amplitudes and phases over the 10 frames.

[0042] S2. Extract the 62 subcarriers at the center of the three DMRS effective subcarrier sequences respectively to obtain the subcarrier sequence at the center of the DMRS effective subcarrier sequence. The specific expression is:

[0043]

[0044] in, Indicates the subcarrier sequence at the center position of the u-th DMRS effective subcarrier sequence, Y DMRSu Indicates the u-th DMRS effective subcarrier sequence, startpoint indicates the starting point of the 62 subcarriers at the center; endpoint indicates the ending point of the 62 subcarriers at the center.

[0045] The positions of these 62 subcarriers are exactly the same as the positions occupied by PSSS and SSSS in the sidecarrier, so the first PSSS effective subcarrier sequence Y PSSS1 , the second PSSS effective subcarrier sequence Y PSSS2 , the first DMRS effective subcarrier sequence Y DMRS1 and the second DMRS effective subcarrier sequence Y DMRS2 The channel response of the first SSSS effective subcarrier sequence Y SSSS1 , the second SSSS effective subcarrier sequence Y SSSS1, the second DMRS effective subcarrier sequence Y DMRS2 and the third DMRS effective subcarrier sequence Y DMRS3 The channel responses are equal.

[0046] Although the second DMRS effective subcarrier sequence Y DMRS2 The channel responses of all other SC-FDAM symbols are approximately equal, but this does not mean that the channel responses of all PSSS, DMRS, and SSSS are approximately equal. Since the time domain positions of PSSS and SSSS in the PSBCH subframe differ greatly, the channel changes over time lead to error accumulation, so the channel responses of PSSS and SSSS are not equal.

[0047] S3. Calculate the cyclic cross-power spectral density of the two PSSS effective subcarrier sequences by frequency domain conjugate multiplication to obtain a first cyclic cross-power spectral density; calculate the cyclic cross-power spectral density of the effective subcarrier sequences at the center positions of the first and second DMRSs to obtain a second cyclic cross-power spectral density; calculate the cyclic cross-power spectral density of the effective subcarrier sequences at the center positions of the second and third DMRSs to obtain a third cyclic cross-power spectral density; calculate the cyclic cross-power spectral density of the two SSSS effective subcarrier sequences to obtain a fourth cyclic cross-power spectral density; the specific formula is:

[0048] P PSSS =Y PSSS1 ·Y * PSSS2

[0049]

[0050] P SSSS =Y SSSS1 ·Y * SSSS2

[0051] Among them, P PSSS represents the first cycle cross power spectrum density, · represents the dot product operation, the superscript * represents the conjugate, P DMRS1 represents the second cyclic cross-power spectral density, Indicates the subcarrier sequence at the center of the first DMRS effective subcarrier sequence, Indicates the subcarrier sequence at the center of the second DMRS effective subcarrier sequence, P DMRS2 represents the third cyclic cross-power spectral density, Indicates the subcarrier sequence at the center of the third DMRS effective subcarrier sequence, P SSSS represents the fourth cyclic cross-power spectral density.

[0052] Figure 4(a) is the amplitude diagram of the four cyclic cross-power spectrum density spliced ​​together for 10 frames of device 1, Figure 4 (b) is a 10-frame phase diagram of the four cyclic cross-power spectrum densities of device 1. It can be seen from the figure that when the vehicle is in the 10-30 km / h scenario, there is still a channel effect that needs to be eliminated.

[0053] The above process has the effect of removing noise, which is explained as follows:

[0054] First, the effective subcarrier sequence Y of the first and second PSSS PSSS1 、Y PSSS2 From the frequency domain to the time domain, we get the time domain sequence y of the first and second PSSS PSSS1 、y PSSS2 ; The subcarrier sequence at the center position of the first, second and third DMRS effective subcarrier sequences Convert from frequency domain to time domain to obtain the time domain sequences of the first, second, and third DMRS: DMRS1 、y DMRS2 、y DMRS3 ; The first and second SSSS effective subcarrier sequences Y SSSS1 、Y SSSS2 From the frequency domain to the time domain, we get the time domain sequence y of the first and second SSSS SSSS1 、y SSSS2 ; The specific expression is:

[0055]

[0056] y PSSSv =IFFT(Y PSSSv )

[0057] y SSSSt =IFFT(Y SSSSt )

[0058] in, The subcarrier sequence representing the center position of the u-th DMRS effective subcarrier sequence, y DMRSu express Time domain series of Y PSSSv The vth PSSS effective subcarrier sequence, y PSSSv Indicates Y PSSSv Time domain series of Y SSSSt The tth SSSS effective subcarrier sequence, y SSSSt Indicates Y SSSSt time domain series.

[0059] Next, calculate the cyclic cross-correlation results of the first and second PSSS time domain sequences to obtain the cyclic cross-correlation results of PSSS; calculate the cyclic cross-correlation results of the first and second DMRS time domain sequences to obtain the cyclic cross-correlation results of the first DMRS; calculate the cyclic cross-correlation results of the first and second SSSS time domain sequences to obtain the cyclic cross-correlation results of SSSS; calculate the cyclic cross-correlation results of the second and third DMRS time domain sequences to obtain the cyclic cross-correlation results of the second DMRS. The specific expression is:

[0060]

[0061] Wherein, γ=0,1……61, a total of 62 points, N=62, mod represents the integer division symbol, n represents the index of the time domain sequence of SC-FDMA (Single-Carrier Frequency-Division Multiple Access) symbols; corr PSSS represents the cyclic cross-correlation result of PSSS; corr DMRS1 Indicates the cyclic cross-correlation result of the first DMRS; corr DMRS2 Represents the cyclic cross-correlation result of the second DMRS; corr SSSS represents the cyclic cross-correlation result of SSSS; y PSSS1 Represents the time domain sequence of the first PSSS effective subcarrier sequence, represents the conjugate of the time domain sequence of the second PSSS effective subcarrier sequence; DMRS1 The time domain sequence of the subcarrier sequence at the center position of the first DMRS effective subcarrier sequence, Represents the conjugate of the time domain sequence of the subcarrier sequence at the center position of the second DMRS effective subcarrier sequence; represents the conjugate of the time domain sequence of the subcarrier sequence at the center position of the third DMRS effective subcarrier sequence; SSSS1 Represents the time domain sequence of the first SSSS effective subcarrier sequence, Represents the conjugate of the time domain sequence of the second SSSS effective subcarrier sequence.

[0062] Since the time domain sequence of PSSS, SSSS, and DMRS symbols can be modeled as y = h*x + z, where h represents the time domain channel response, x represents the SC-FDMA sequence without channel and noise, z represents additive noise, and * represents the convolution operation, the above formula can be further transformed into:

[0063]

[0064] Among them, h PSSS1is the time domain channel response of the first PSSS effective subcarrier sequence, h PSSS2 is the time domain channel response of the second PSSS effective subcarrier sequence, h DMRS1 is the time domain channel response of the subcarrier sequence at the center of the first DMRS effective subcarrier sequence, h DMRS2 is the time domain channel response of the subcarrier sequence at the center of the second DMRS effective subcarrier sequence, h DMRS3 is the time domain channel response of the subcarrier sequence at the center of the third DMRS effective subcarrier sequence, h SSSS1 is the time domain channel response of the first SSSS effective subcarrier sequence, h SSSS2 is the time domain channel response of the second SSSS effective subcarrier sequence. PSSS1 is the time domain sequence of the first PSSS effective subcarrier sequence without channel and noise, x PSSS2 is the time domain sequence of the second PSSS effective subcarrier sequence without channel and noise, x DMRS1 is the time domain sequence of the subcarrier sequence at the center position of the first DMRS effective subcarrier sequence without channel and noise, x DMRS2 is the time domain sequence of the subcarrier sequence at the center position of the second DMRS effective subcarrier sequence without channel and noise, x DMRS3 is the time domain sequence of the subcarrier sequence at the center position of the third DMRS effective subcarrier sequence without channel and noise, x SSSS1 is the time domain sequence of the first SSSS effective subcarrier sequence without channel and noise, x SSSS2 is the time domain sequence of the second SSSS effective subcarrier sequence without channel and noise. PSSS1 is the time domain additive noise of the first PSSS effective subcarrier sequence, z PSSS2 is the time domain additive noise of the second PSSS effective subcarrier sequence, z DMRS1 is the time domain additive noise of the subcarrier sequence at the center of the first DMRS effective subcarrier sequence, z DMRS2 is the time domain additive noise of the subcarrier sequence at the center of the second DMRS effective subcarrier sequence, z DMRS3 is the time domain additive noise of the subcarrier sequence at the center of the third DMRS effective subcarrier sequence, z SSSS1 is the time domain additive noise of the first SSSS effective subcarrier sequence, z SSSS2 is the time domain additive noise of the second SSSS effective subcarrier sequence.

[0065] Since the noise in the above formula is a stationary process with a mean of 0, the noise z in the above formula is eliminated and the expression can be transformed into:

[0066]

[0067] Converting the above formula into the frequency domain, the expression becomes the form of cyclic cross-power spectrum density, which is as follows:

[0068] P PSSS =FFT(corr PSSS )

[0069] P DMRS1 =FFT(corr DMRS1 )

[0070] P DMRS2 =FFT(corr DMRS2 )

[0071] P SSSS =fft(corr SSSS )

[0072] Here, FFT stands for Fourier transform.

[0073] S4. Obtain a first cyclic cross-power spectrum quotient based on the first cyclic cross-power spectrum density and the second cyclic cross-power spectrum density; obtain a second cyclic cross-power spectrum quotient based on the third cyclic cross-power spectrum density and the fourth cyclic cross-power spectrum density; the specific formula is:

[0074]

[0075] Among them, PQ (PSSS,DMRS1) represents the first cyclic cross-power quotient, PQ (SSSS,DMRS2) represents the second cyclic cross-power spectrum quotient, P H1 represents the first channel cyclic power spectrum, P PSSS_RFF represents the cyclic cross power spectrum of PSSS including RF fingerprint features, P DMRS1_RFF P represents the cyclic cross power spectrum of the first and second DMRS containing the radio frequency fingerprint feature, H2 represents the second channel cyclic power spectrum, P SSSS_RFF represents the cyclic cross power spectrum of SSSS containing RF fingerprint features, P DMRS2_RFF Indicates the cyclic cross power spectrum of the second and third DMRSs containing the radio frequency fingerprint feature.

[0076] S5. Concatenate the first cyclic cross-power spectrum quotient and the second cyclic cross-power spectrum quotient to obtain the radio frequency fingerprint of the PSBCH. The specific formula is:

[0077] PQ=concat(PQ (PSSS,DMRS1) ,PQ (SSSS,DMRS2) )

[0078] Among them, PQ represents the radio frequency fingerprint of PSBCH.

[0079] Figure 5 (a) is the amplitude diagram of the PSBCH RF fingerprint of device 1 for 10 consecutive frames. Figure 5 (b) is the phase diagram of the PSBCH RF fingerprint of device 1 for 10 consecutive frames. Figure 5 (c) is the amplitude diagram of the PSBCH RF fingerprint of device 2 for 10 consecutive frames. Figure 5 (d) is the phase diagram of the PSBCH RF fingerprint of device 2 for 10 consecutive frames. Figure 5 (e) is the amplitude diagram of the PSBCH RF fingerprint of device 3 for 10 consecutive frames. Figure 5 Figure (f) shows the phase diagram of the PSBCH RF fingerprint of device 3 over 10 consecutive frames. It can be seen that even when the vehicle is traveling at 10-30 km / h, the cyclic cross-power spectrum quotient characteristics of different devices tend to be stable. Furthermore, the cyclic cross-power spectrum quotient characteristics of different devices are significantly different, indicating that the RF fingerprints of different devices are different.

[0080] An embodiment of the present invention further provides an electronic device comprising a memory, a processor, and a computer program stored in the memory and executable by the processor. It should be noted that when the processor executes the computer program, it corresponds to the specific steps of the method provided in the embodiment of the present invention and has the corresponding functional modules and beneficial effects of the method. For technical details not fully described in this embodiment, please refer to the method provided in the embodiment of the present invention.

[0081] The present invention also provides a computer-readable storage medium storing a computer program. It should be noted that when executed by a processor, the computer program corresponds to the specific steps of the method provided in the present invention and has the corresponding functional modules and beneficial effects. For technical details not fully described in this embodiment, please refer to the method provided in the present invention.

[0082] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross power spectrum quotient features, characterized in that: include: S1. The receiver receives the PSBCH sent by the LTE-V2X terminal, converts it into a baseband signal, extracts the two PSSS, three DMRS and two SSSS effective subcarriers in the baseband signal, and obtains an effective subcarrier sequence; S2. Extract the correlation sequences of the subcarriers at the center positions of the three DMRS effective subcarrier sequences respectively to obtain the subcarrier sequences at the center positions of the three DMRS effective subcarrier sequences; S3. Calculate the cyclic cross-power spectral density of the two PSSS effective subcarrier sequences to obtain a first cyclic cross-power spectral density; calculate the cyclic cross-power spectral density of the subcarrier-related sequence at the center position of the effective subcarrier sequences of the first and second DMRSs to obtain a second cyclic cross-power spectral density; calculate the cyclic cross-power spectral density of the subcarrier-related sequence at the center position of the effective subcarrier sequences of the second and third DMRSs to obtain a third cyclic cross-power spectral density; calculate the cyclic cross-power spectral density of the two SSSS effective subcarrier sequences to obtain a fourth cyclic cross-power spectral density; S4. Obtaining a first cyclic cross-power spectrum quotient based on the first cyclic cross-power spectrum density and the second cyclic cross-power spectrum density; obtaining a second cyclic cross-power spectrum quotient based on the third cyclic cross-power spectrum density and the fourth cyclic cross-power spectrum density; S5. Concatenate the first cyclic cross-power spectrum quotient and the second cyclic cross-power spectrum quotient to obtain a radio frequency fingerprint of the PSBCH.

2. The method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross power spectrum quotient characteristics according to claim 1, characterized in that: In step S1, the effective subcarrier sequence Y of the first and second PSSS PSSS1 、Y PSSS2 Each includes 62 effective subcarriers, and the effective subcarrier sequence Y of the first, second and third DMRS DMRS1 、Y DMRS2 、Y DMRS3 Each includes 72 effective subcarriers, and the effective subcarrier sequence Y of the first and second SSSS SSSS1 、Y SSSS2 Both include 62 effective subcarriers.

3. The method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross power spectrum quotient characteristics according to claim 2, characterized in that: In step S2, 62 effective subcarriers at the center positions of the three DMRS effective subcarrier sequences are extracted respectively to obtain the effective subcarrier sequence at the center position of the DMRS. The specific expression is: in, Indicates the subcarrier sequence at the center position of the u-th DMRS effective subcarrier sequence, Y DMRSu Indicates the u-th DMRS effective subcarrier sequence, startpoint indicates the starting point of the 62 subcarriers at the center; endpoint indicates the ending point of the 62 subcarriers at the center.

4. The method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross power spectrum quotient characteristics according to claim 3, characterized in that: In step S3, the calculation formula of the cyclic cross power spectrum density is: P PSSS =And PSSS1 ·AND * PSSS2 P SSSS =And SSSS1 ·AND * SSSS2 Among them, P PSSS represents the first cycle cross power spectrum density, · represents the dot product operation, * represents the conjugate, P DMRS1 represents the second cyclic cross-power spectral density, Indicates the subcarrier sequence at the center of the first DMRS effective subcarrier sequence, Indicates the subcarrier sequence at the center of the second DMRS effective subcarrier sequence, P DMRS2 represents the third cyclic cross-power spectral density, Indicates the subcarrier sequence at the center of the third DMRS effective subcarrier sequence, P SSSS represents the fourth cyclic cross-power spectral density.

5. The method for extracting radio frequency fingerprint of physical side link broadcast channel based on cyclic cross power spectrum quotient characteristics according to claim 1, characterized in that: In step S4, the calculation formula of the cyclic cross power spectrum quotient is: Among them, PQ (PSSS,DMRS1) represents the first cyclic cross-power quotient, PQ (SSSS,DMRS2) represents the second cyclic cross-power spectrum quotient, P PSSS represents the first cycle cross power spectrum density, P DMRS1 represents the second cyclic cross power spectral density, P SSSS represents the fourth cycle cross power spectral density, P DMRS2 represents the third cycle cross power spectrum density, P H1 represents the first channel cyclic power spectrum, P PSSS_RFF represents the cyclic cross power spectrum of PSSS including RF fingerprint features, P DMRS1_RFF P represents the cyclic cross power spectrum of the first and second DMRS containing the radio frequency fingerprint feature, H2 represents the second channel cyclic power spectrum, P SSSS_RFF represents the cyclic cross power spectrum of SSSS containing RF fingerprint features, P DMRS2_RFF Indicates the cyclic cross power spectrum of the second and third DMRSs containing the radio frequency fingerprint feature.

6. The method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross power spectrum quotient characteristics according to claim 1, characterized in that: In step S5, the calculation formula of the radio frequency fingerprint of PSBCH is: PQ=concat(PQ (PSSS,DMRS1) ,PQ (SSSS,DMRS2) ) Among them, PQ represents the radio frequency fingerprint of PSBCH, PQ (PSSS,DMRS1) represents the first cyclic cross-power quotient, PQ (SSSS,DMRS2) represents the second cyclic cross-power spectrum quotient.

7. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein: When the processor executes the computer program, the steps of the method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross power spectrum quotient features as described in any one of claims 1 to 6 are implemented.

8. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for extracting radio frequency fingerprints of physical side link broadcast channels based on cyclic cross power spectrum quotient features according to any one of claims 1 to 6 is executed.

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