A radar communication integrated signal design method based on FBMC comb spectrum

Abstract

The present invention belongs to the field of radar communication integrated signal processing technology, and discloses a radar communication integrated signal design method based on FBMC comb spectrum, comprising the following steps: generating an original chirp signal (linear frequency modulation signal) r(t); extending the original chirp signal r(t) in time domain by M-1 times to obtain a time domain chirp signal, and performing FFT (fast Fourier transform) on the time domain chirp signal to obtain a radar chirp signal; modulating the discrete spectrum value of the radar chirp signal to the 1st, M+1, 2M+1, ..., (a-1)·M+1) subcarriers of the FBMC comb spectrum signal to generate an original phase coding sequence, performing digital modulation and serial-to-parallel conversion operations on the original phase coding sequence to obtain discrete communication data; separating the discrete communication data into real and imaginary parts, and inserting the real and imaginary parts of the separated discrete communication data into adjacent frequency points of the discrete spectrum of the radar chirp signal. The radar communication integrated signal design method based on FBMC comb spectrum proposes a leading sequence that integrates auxiliary pilots and interference utilization algorithms to improve channel estimation accuracy.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar communication integrated signal processing, and in particular relates to a radar communication integrated signal design method based on FBMC comb spectrum. Background Art

[0002] OFDM technology has attracted wide attention in the design of integrated signals due to its advantages such as flexible carrier modulation and high spectrum efficiency. Among them, OFDM comb spectrum technology is one of the alternative integrated technologies. However, OFDM technology also has some shortcomings. For example, it is very sensitive to frequency deviation and is susceptible to severe inter-carrier interference. In comparison, FBMC technology has a higher Doppler tolerance and does not require CP. It has become one of the important potential technologies for integrated radar communication signals. In order to reduce the sidelobes of frequency domain subcarriers, FBMC needs to use a specially designed prototype filter, which will introduce fixed imaginary interference on each subcarrier, which will cause a serious decline in radar detection performance and communication performance. Summary of the invention

[0003] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a radar communication integrated signal design method based on FBMC comb spectrum, which solves the problems mentioned in the background technology.

[0004] The purpose of this disclosure can be achieved through the following technical solutions:

[0005] A radar communication integrated signal design method based on FBMC comb spectrum includes the following steps:

[0006] Generate the original chirp signal (linear frequency modulation signal) r(t);

[0007] The original chirp signal r(t) is extended in time domain by M-1 times to obtain a time domain chirp signal, and the time domain chirp signal is subjected to FFT (Fast Fourier Transform) to obtain a radar chirp signal;

[0008] The discrete spectrum value of the radar chirp signal is modulated onto the 1st, M+1st, 2M+1st, ..., (a-1)·M+1st) subcarriers of the FBMC comb spectrum signal to generate an original phase coding sequence, and the original phase coding sequence is digitally modulated and serial-to-parallel converted to obtain discrete communication data;

[0009] Separating the real and imaginary parts of the discrete communication data, and inserting the separated real and imaginary parts of the discrete communication data between adjacent frequency points of the discrete spectrum of the radar chirp signal; wherein the real part of the discrete communication data is placed on the odd-numbered symbols, and the imaginary part of the discrete communication data is placed on the even-numbered symbols;

[0010] The radar data on the odd-numbered symbols of the FBMC comb spectrum signal (integrated signal) is set to zero, and a blank guard interval is placed at the upper and lower subcarriers of the radar chirp complex signal in the odd-numbered symbols and even-numbered symbols of each FBMC comb spectrum signal;

[0011] Two columns of block pilot symbols are inserted before the FBMC comb spectrum signal to be transmitted, pilot data is placed at the odd subcarrier position of the second symbol, and real and imaginary numbers are placed at the even subcarrier positions of the first and second symbols to increase the power of the pilot point;

[0012] The value of the auxiliary pilot is calculated according to the interference value caused by the fourth-order data around the pilot to the pilot point, and the auxiliary pilot is placed at the odd subcarrier position of the first symbol;

[0013] At the radar receiving end, the radar chirp data modulated in the FBMC comb spectrum signal is extracted and radar signal processing is performed to obtain the speed and position information of the target to be measured;

[0014] At the communication receiving end, the communication code elements modulated in the FBMC comb spectrum signal are extracted, and channel estimation is performed on the communication code elements;

[0015] After the communication code elements are estimated through the channel, the communication data can be obtained through channel equalization, digital demodulation and decoding.

[0016] Preferably, for fast time-varying channels, channel estimation is performed by combining block pilots and discrete radar chirp signals.

[0017] Preferably, M is the number of intervals between adjacent radar frequency points, and a is the number of subcarriers occupied by the radar chirp.

[0018] Preferably, the time domain model of the FBMC comb spectrum signal is as follows:

[0019]

[0020] in,

[0021]

[0022]

[0023] aM is the number of subcarriers, N is the number of symbols, g(k) represents the prototype filter with a length of K×aM, b m,n is the weight of the mth subcarrier on the nth symbol; the phase factor Make the integrated signal real and virtual interlaced in time domain and frequency domain; g(k) is in phase Construct a filter bank; r m,n is the radar chirp discrete spectrum value, c m,nis the communication discrete spectrum value, m, n represent the subcarrier and symbol position respectively, c m,n is a real number, r m,n Is plural.

[0024] Preferably, if g m (k) = g(k)e j2πmk / aM ;

[0025] Then n (k) can be simplified as:

[0026] Preferably, filter bank multi-carrier OQAM / FBMC based on offset quadrature amplitude modulation is used to send and receive pilot symbols, auxiliary symbols and data symbols.

[0027] Preferably, by y p,q is the received pilot data, a p,q is the pilot data sent, u p,q is the interference of the number of pilot points placed on the even subcarriers of the first and second symbols, η p,q is Gaussian white noise, and the channel response of the pilot point can be obtained;

[0028] Preferably, the complete channel response H of all symbols is obtained by linearly interpolating the pilot point channel response m,n .

[0029] A device comprising:

[0030] one or more processors;

[0031] A memory for storing one or more programs;

[0032] When one or more of the programs are executed by one or more of the processors, one or more of the processors implement the above-mentioned radar communication integrated signal design method based on FBMC comb spectrum.

[0033] A storage medium containing computer executable instructions, wherein the computer executable instructions are used to execute the above-mentioned radar communication integrated signal design method based on FBMC comb spectrum when executed by a computer processor.

[0034] Beneficial effects of the present disclosure:

[0035] In order to solve the problem of communication performance degradation caused by the inherent imaginary interference of the FBMC system, the present invention proposes a leading sequence that integrates auxiliary pilots and interference utilization algorithms to improve the accuracy of channel estimation. When dealing with fast time-varying channels, the present invention combines the leading sequence and the discrete spectrum of the chirp signal to perform channel estimation, thereby improving the communication performance of the FBMC comb spectrum signal; compared with the OFDM comb spectrum, the FBMC comb spectrum has a higher Doppler tolerance. In high-speed mobile scenarios, it has better radar detection performance and high-speed wireless communication performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0037] Figure 1 It is a block diagram of a radar communication integrated system based on FBMC comb spectrum according to an embodiment of the present disclosure;

[0038] Figure 2 is a flowchart of the communication receiving end processing in the embodiment of the present disclosure;

[0039] Figure 3 is a flowchart of the radar receiving end processing in the embodiment of the present disclosure;

[0040] Figure 4 It is a time-frequency characteristic diagram of the FBMC comb spectrum of an embodiment of the present disclosure;

[0041] Figure 5 is a radar point expansion function diagram of an embodiment of the present disclosure;

[0042] Figure 6 It is the FBMC comb spectrum PD diagram of the embodiment of the present disclosure;

[0043] Figure 7 The FBMC comb spectrum communication terminal receives the image in the embodiment of the present disclosure;

[0044] Figure 8 is a constellation diagram of a receiving end of FBMC comb spectrum communication according to an embodiment of the present disclosure;

[0045] Fig. 9 This is the OFDM comb spectrum PD diagram of the embodiment of the present disclosure;

[0046] Fig.10 The OFDM comb spectrum communication terminal receives the image in the embodiment of the present disclosure;

[0047] Fig.11 is a constellation diagram of an OFDM comb spectrum communication receiving end according to an embodiment of the present disclosure;

[0048] Fig.12 2 is a diagram of experimental parameters involved in the embodiments of the present disclosure. DETAILED DESCRIPTION

[0049] The following will be combined with the drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are only part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present disclosure.

[0050] The experimental parameters involved in this embodiment are as follows Fig.12 As shown in the figure, the framework diagram of FBMC radar communication integrated system is as follows Figure 1 , 2 , 3, as follows

[0051]

[0052] in,

[0053]

[0054] aM is the number of subcarriers, N is the number of symbols, g(k) represents the prototype filter with a length of K×aM, b m,n is the weight of the mth subcarrier on the nth symbol. Phase factor Make the integrated signal real and virtual interlaced in the time domain and frequency domain. g(k) is in phase Construct a filter bank. m,n is the radar chirp discrete spectrum value, c m,n is the communication discrete spectrum value (m,n represent the subcarrier and symbol position respectively, c m,n is a real number, r m,n is plural).

[0055] 2. If

[0056]

[0057]

[0058] g m (k) = g(k)e j2πmk / aM

[0059] 3.

[0060]

[0061] 4. In order to reduce the interference between radar data and the interference of radar complex data on communication real data,

[0062]

[0063] The sum of the high-order interference caused by the integrated data and the interference caused by the auxiliary pilot at the pilot point is:

[0064]

[0065] 8. In order to eliminate the high-order interference generated by the integrated data, it is necessary to design the value of the auxiliary pilot so that u' p,q = 0. The value of the auxiliary pilot point b p,q-1 At the time u' p,q =0 takes the following values:

[0066]

[0067] 9. The value of the auxiliary pilot can be obtained from step 8, and the auxiliary pilot is placed at the odd subcarrier position of the first symbol to offset the high-order imaginary interference of the pilot symbol;

[0068] For the classic PHYDYAS prototype filter, the number of data symbols that will cause large imaginary interference to the pilot symbol at the (p, q) time-frequency point is 26, and its time-frequency distribution area is the upper and lower first-order domains where the pilot point is located, and the left and right fourth-order domains, that is, The corresponding interference coefficients are (0.0054, 0.0429, 0.1250, 0.2058, 0.2393, 0.2058, 0.1250, 0.0429, 0.0054; 0, 0.0668, 0, 0.5644, 1, -0.5644, 0, -0.0668, 0; -0.0054, 0.0429, -0.1250, 0.2058, -0.2393, 0.2058, -0.1250, 0.0429, 0.0054)*1j, where j is the imaginary unit.

[0069] The time-frequency characteristics of the transmitted FBMC comb spectrum signal are shown in the figure below: Figure 4 As shown;

[0070] Radar point expansion function is as follows Figure 5 As shown;

[0071] At the receiving end, when SNR=25dB, the scene contains four point targets m1, m2, m3, and m4. The radar scattering cross sections (RCS) of these four point targets are 0.3m2, 0.4m2, 0.5m2, and 0.6m2, respectively. The radial velocities relative to the integrated system are 62.5m / s, 25m / s, -50m / s, and 37.5m / s, respectively. The distances relative to the integrated system are 300m, 350m, 500m, and 600m, respectively. At the radar receiving end, the integrated received signal extracts the radar chirp data modulated in the FBMC comb spectrum signal and performs classic PD processing. The processing results are as follows: Figure 6 shown.

[0072] At the communication receiving end, the communication code elements modulated in the FBMC comb spectrum signal are extracted, and channel estimation, channel equalization, digital demodulation, decoding and other operations are performed on the communication code elements to obtain the communication data. Figure 7 As shown, the constellation diagram is Figure 8 shown.

[0073] The OFDM comb spectrum signal is simulated under the same parameters. The PD processing results, the communication end receiving image, and the constellation diagram are shown as follows: Fig. 9 , 10 , as shown in 11.

[0074] Compared with OFDM comb spectrum, the FBMC comb spectrum signal designed by the present invention has the feasibility of realizing radar and communication simultaneously, in the same airspace, and efficiently sharing the spectrum. In addition, the FBMC comb spectrum signal also has a higher Doppler tolerance, meeting the needs of high dynamic applications.

[0075] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present disclosure. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0076] The above shows and describes the basic principles, main features and advantages of the present disclosure. Those skilled in the art should understand that the present disclosure is not limited by the above embodiments, and the above embodiments and descriptions are only for explaining the principles of the present disclosure. Without departing from the spirit and scope of the present disclosure, the present disclosure may have various changes and improvements, and these changes and improvements fall within the scope of the present disclosure to be protected.

Claims

1. A radar communication integrated signal design method based on FBMC comb spectrum, comprising the following steps: Generate the original chirp signal r(t); The original chirp signal r(t) is extended in time domain by M-1 times to obtain a time domain chirp signal, and the time domain chirp signal is subjected to fast Fourier transform to obtain a radar chirp signal; The discrete spectrum value of radar chirp signal is modulated to the first On the subcarrier, an original phase coding sequence is generated, and the original phase coding sequence is digitally modulated and serial-to-parallel converted to obtain discrete communication data; wherein, is the interval between adjacent radar frequency points, is the number of subcarriers occupied by radar chirp; Separating the real and imaginary parts of the discrete communication data, and inserting the separated real and imaginary parts of the discrete communication data between adjacent frequency points of the discrete spectrum of the radar chirp signal; wherein the real part of the discrete communication data is placed on the odd-numbered symbols, and the imaginary part of the discrete communication data is placed on the even-numbered symbols; The radar data on the odd-numbered symbols of the FBMC comb spectrum signal is set to zero, and a blank guard interval is placed at the upper and lower subcarriers of the radar chirp complex signal in the odd-numbered symbols and even-numbered symbols of each FBMC comb spectrum signal; Two columns of block pilot symbols are inserted before the FBMC comb spectrum signal to be transmitted, pilot data is placed at the odd subcarrier position of the second symbol, and real and imaginary numbers are placed at the even subcarrier positions of the first and second symbols to increase the power of the pilot point; The value of the auxiliary pilot is calculated according to the interference value caused by the fourth-order data around the pilot to the pilot point, and the auxiliary pilot is placed at the odd subcarrier position of the first symbol; At the radar receiving end, the radar chirp data modulated in the FBMC comb spectrum signal is extracted and radar signal processing is performed to obtain the speed and position information of the target to be measured; At the communication receiving end, the communication code elements modulated in the FBMC comb spectrum signal are extracted, and channel estimation is performed on the communication code elements; After the communication code elements are estimated through the channel, the communication data can be obtained through channel equalization, digital demodulation and decoding.

2. According to claim 1, a radar communication integrated signal design method based on FBMC comb spectrum is characterized in that: For fast time-varying channels, channel estimation is performed by combining block pilots and discrete radar chirp signals.

3. The radar communication integrated signal design method based on FBMC comb spectrum according to claim 1 is characterized in that: The time domain model of the FBMC comb spectrum signal is as follows: in, is the number of subcarriers, is the number of symbols, Indicates the length The prototype filter, For the The first symbol The weight of the subcarrier; the phase factor Make the integrated signal real and virtual interlaced in time domain and frequency domain; In phase Constructing a filter bank; is the radar chirp discrete spectrum value, is the communication discrete spectrum value, , represent the subcarrier and symbol positions respectively, is a real number, Is plural.

4. The radar communication integrated signal design method based on FBMC comb spectrum according to claim 3 is characterized in that: If you , , ; but Can be simplified to: .

5. The radar communication integrated signal design method based on FBMC comb spectrum according to claim 1 is characterized in that: Pilot symbols, auxiliary symbols and data symbols are sent and received using filter bank multi-carrier OQAM / FBMC based on offset quadrature amplitude modulation.

6. The radar communication integrated signal design method based on FBMC comb spectrum according to claim 1 is characterized in that: Depend on , is the received pilot data, is the pilot data sent, is the interference of the number of pilot points placed on the even subcarriers of the first and second symbols, is Gaussian white noise, and the channel response of the pilot point can be obtained.

7. The radar communication integrated signal design method based on FBMC comb spectrum according to claim 1 is characterized in that: By linearly interpolating the pilot point channel response, the complete channel response of all symbols is obtained .

8. A storage medium containing computer executable instructions, characterized in that: It includes a radar communication integrated signal design method based on FBMC comb spectrum as described in any one of claims 1-7, and the computer executable instructions are used to execute the above-mentioned radar communication integrated signal design method based on FBMC comb spectrum when executed by a computer processor.

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