Interference-communication integrated waveform generation method based on frequency modulation slope mismatch interference

Abstract

The present invention proposes an integrated waveform generation method for interference communication based on frequency modulation slope mismatch interference, and its implementation steps are as follows: initialize parameters; divide the binary bit data to be transmitted; obtain the frequency modulation slope of the frequency modulation slope mismatch interference signal; obtain the carrier frequency of the frequency modulation slope mismatch interference signal; obtain the integrated waveform of interference communication. The present invention uses the frequency modulation slope and carrier frequency of the frequency modulation slope mismatch interference to carry communication information. The communication information maps one from a set of frequency modulation slope sequences as the frequency modulation slope of frequency modulation slope mismatch interference signals with different carrier frequencies, and maps multiple carrier frequencies from the carrier frequency sequence as the carrier frequencies of frequency modulation slope mismatch interference signals with different carrier frequencies. By simultaneously transmitting multiple frequency modulation slope mismatch interference signals with the same frequency modulation slope but different carrier frequencies, the number of communication bits transmitted within the duration of the radar signal is increased, achieving the purpose of improving the communication rate.

Description

Technical Field

[0001] The present invention belongs to the technical field of radar jamming and communication, and relates to a waveform generation method, and further relates to an integrated jamming and communication waveform generation method based on frequency modulation slope mismatch jamming, which can be used to jam a radar while realizing communication information transmission. Background Art

[0002] Traditional radar jamming and communication systems have developed independently as two separate subsystems. The disadvantage is that after the jamming device obtains jamming information, it needs to transmit the information to the receiving end through a communication device, wasting a certain amount of time and system resources, and making it impossible to transmit communication information in a timely and accurate manner. With the development of science and technology, the application scenarios of the two have been expanded, and the differences are gradually decreasing. There are more and more overlapping parts in the working frequency band; there are overlapping functions in the hardware structure, both of which include radio transmitting devices and data processing devices. If the radar jamming system and the communication system are integrated to design an integrated jamming and communication system, which can jam the radar while also transmitting communication information in real time, this can not only overcome the above problems, but also improve the overall working efficiency of the system.

[0003] The research on the integrated jamming and communication system is actually to design a comprehensive system with both information transmission ability and radar jamming ability on the same device. This system can achieve an equilibrium in terms of radar jamming effect, communication transmission rate, and bit error rate, and can make full use of the advantages of radar jamming signals to improve communication performance. For example, using the high power of radar jamming signals to expand the communication range and improve the bit error rate performance of communication; the radar jamming signal aims to jam the radar detection target, and the radar signal processing end will suppress it, thereby protecting the secure transmission of its own communication information.

[0004] Existing integrated jamming and communication waveform generation methods, for example, in the literature "LIU G G, YANG W B, WANG Y M, et al. Joint communication interference system design based on parameter modulation [J]. Applied Optics, 2022, 61(4): 1057-1067.", a method for designing an integrated jamming and communication waveform based on parameter modulation is disclosed. This method maps a frequency modulation slope and a carrier frequency as a frequency modulation slope mismatch jamming signal from the designed frequency modulation slope sequence and carrier frequency sequence respectively using communication information to achieve integrated waveform design. However, this method continuously sends the same frequency modulation slope mismatch jamming signal at intervals of the communication symbol duration within the radar coherent processing time, resulting in a low communication rate of the waveform. Summary of the Invention

[0005] The object of the present invention is to address the deficiencies of the above-mentioned existing technologies and propose an integrated waveform generation method for interference communication based on frequency modulation slope mismatch interference, which is used to solve the technical problem of low waveform communication rate in the existing technologies.

[0006] To achieve the above object, the technical solution adopted by the present invention includes the following steps:

[0007] (1) Initialize parameters:

[0008] Initialize the duration, frequency modulation slope, and carrier frequency of the radar signal r(t) to T, μ, and f respectively, and the sampling frequency of the communication end is f s , K frequency modulation slopes with an interval of Δμ and increasing values in sequence U = {μ k | 1 ≤ k ≤ K} and L carrier frequencies with an interval of Δf and increasing values in sequence F = {f l | 1 ≤ l ≤ L}, where K = 2 M , M is the number of binary bits that the K frequency modulation slopes in U can map, M ≥ 1, L = 2 J , J is the number of binary bits that the L carrier frequencies in F can map, J ≥ 2 and is an even number, μ k represents the k-th frequency modulation slope, f l represents the l-th carrier frequency, t represents the fast time, t0 ≤ t ≤ t0 + T, t0 is the starting time of r(t), the sampling frequency f s , frequency modulation slope μ k , carrier frequency f l , the frequency modulation slope μ of r(t), and the carrier frequency f of r(t) need to satisfy the following relationships:

[0009]

[0010] (2) Divide the binary bit data to be transmitted:

[0011] Select the first M bits of binary bit data in the data frame S to be transmitted, which includes N bits of binary bit data, to form the data frame S1 = {s m | 1 ≤ m ≤ M}, and evenly divide the remaining N - M bits of binary bit data into I groups to obtain the data frame group set G = {g i | 1 ≤ i ≤ I}, g i = {s iq | 1 ≤ q ≤ Q}, where s m represents the m-th bit of binary bit data in S1, g i represents the i-th data frame group in G that contains Q bits of binary bit data, s iq represents the q-th bit of binary bit data in g i , N = M + I × Q, I = 2 Q, Q = J / 2;

[0012] (3) Obtain the frequency modulation slope of the frequency modulation slope mismatch interference signal:

[0013] Represent the data frame S1 as a decimal number and select the order from the K frequency modulation slopes U and The corresponding frequency modulation slope is used as the frequency modulation slope of the frequency modulation slope mismatch interference signal;

[0014] (4) Obtain the carrier frequency of the frequency modulation slope mismatch interference signal:

[0015] (4a) Represent the order i in g i as a Q-bit binary number d i , and add d i to the end of the data frame group g i to obtain the carrier frequency data frame group set G corresponding to the data frame group set G f ={g fi |1≤i≤I}, where g fi represents the i-th carrier frequency data frame group in G f ;

[0016] (4b) Represent all the binary bit data in each carrier frequency data frame group g f in G fi as a decimal number to obtain the carrier frequency decimal number set where, represents the i-th carrier frequency decimal number in;

[0017] (4c) Select I orders from the L carrier frequencies F and each The corresponding carrier frequency is used as the carrier frequency of the I frequency modulation slope mismatch interference signals;

[0018] (5) Obtain the integrated interference communication waveform:

[0019] According to the obtained frequency modulation slope of the frequency modulation slope mismatch interference signal and the carrier frequency of each frequency modulation slope mismatch interference signal, use a signal generator to generate I frequency modulation slope mismatch interference signals and superimpose them at the transmitting end to obtain the integrated interference communication waveform s(t).

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The present invention uses the frequency modulation slope and carrier frequency of the frequency modulation slope mismatch interference to carry communication information. The communication information maps a frequency modulation slope from a set frequency modulation slope sequence as a frequency modulation slope mismatch interference signal with different carrier frequencies for multiple carriers, and maps multiple carrier frequencies from the carrier frequency sequence as carrier frequencies of frequency modulation slope mismatch interference signals with different carrier frequencies for multiple carriers. By simultaneously transmitting frequency modulation slope mismatch interference signals with the same frequency modulation slope and different carrier frequencies, the influence of the prior art on the communication rate caused by continuously transmitting the same frequency modulation slope mismatch interference signal at intervals of the communication symbol duration within the radar coherent processing time is avoided, the number of communication bits transmitted within the radar signal duration is increased, and the communication rate of the waveform is effectively improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a flowchart for implementing the present invention;

[0023] Figure 2 is a comparison chart of the communication rates between the present invention and the prior art. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] The following further describes the present invention in detail with reference to the drawings and embodiments.

[0025] Referring to the attached Figure 1 , the present invention includes the following steps:

[0026] Step 1) Initialize parameters:

[0027] Initialize the duration, frequency modulation slope, and carrier frequency of the radar signal r(t) to T, μ, and f respectively, and the sampling frequency of the communication end is f s , K frequency modulation slopes U = {μ k | 1 ≤ k ≤ K} with an interval of Δμ and increasing values in sequence and L carrier frequencies F = {f l | 1 ≤ l ≤ L} with an interval of Δf and increasing values in sequence, where K = 2 M , M is the number of binary bits that can be mapped by the K frequency modulation slopes in U, M ≥ 1, L = 2 J , J is the number of binary bits that can be mapped by the L carrier frequencies in F, J ≥ 2 and is an even number, μ k represents the k-th frequency modulation slope, f l represents the l-th carrier frequency, t represents the fast time, t0 ≤ t ≤ t0 + T, t0 is the starting time of r(t), the sampling frequency f s , the frequency modulation slope μ k , the carrier frequency f l , the frequency modulation slope μ of r(t), and the carrier frequency f of r(t) need to satisfy the following relationship:

[0028]

[0029] Since pulse compression processing of radar signals suppresses frequency components outside the radar bandwidth, the above parameter relationship can ensure that the radar signal bandwidth is greater than the integrated waveform bandwidth, maximizing the energy utilization rate of the integrated signal.

[0030] The expression of the radar signal r(t) is:

[0031]

[0032] where exp(·) is the exponential function, j represents the imaginary unit, and rect(·) represents the rectangular envelope function.

[0033] Set the radar signal duration T = 20 μs, the radar signal frequency modulation slope μ = 1×10 12 Hz / s, the radar signal carrier frequency f = 0 GHz, the sampling frequency f s = 10 MHz, the set of frequency modulation slopes U = {7×10 11 , 7.5×10 11}} Hz / s, the set of carrier frequencies F = {0, f s / 128, …, 63f s / 128}, in this example, M = 1, L = 64, J = 6.

[0034] Step 2) Divide the binary bit data to be transmitted:

[0035] Select the first M binary bit data in the data frame S to be transmitted, which includes N binary bit data, to form the data frame S1 = {s m |1 ≤ m ≤ M}, and evenly divide the remaining N - M binary bit data into I groups to obtain the data frame group set G = {g i |1 ≤ i ≤ I}, g i = {s iq |1 ≤ q ≤ Q}, where s m represents the m-th binary bit data in S1, g i represents the i-th data frame group in G that contains Q binary bit data, s iq represents the q-th binary bit data in g i , N = M + I×Q, I = 2 Q . In this example, I = 8, Q = 3, N = 25.

[0036] Step 3) Obtain the frequency modulation slope of the frequency modulation slope mismatch interference signal:

[0037] Represent the data frame S1 as a decimal number and select the corresponding frequency modulation slope from the K frequency modulation slopes U as the frequency modulation slope of the frequency modulation slope mismatch interference signal. ​

[0038] The communication receiving end performs multi-channel de-slanting processing on the received integrated waveform according to the frequency modulation slope in U, and determines the de-slanting channel of the single-carrier frequency signal through subsequent fast Fourier transform. The frequency modulation slope of this channel is used as the frequency modulation slope of the integrated signal, and then through the mapping relationship with the communication information, the communication information represented by the frequency modulation slope is obtained.

[0039] Step 4) Obtain the carrier frequency of the frequency modulation slope mismatch interference signal:

[0040] (4a) Represent the sequence i in g i as a Q-bit binary number d i , and add d i to the end of the data frame group g i to obtain the set of carrier frequency data frame groups G corresponding to the data frame group set G f = {g fi | 1 ≤ i ≤ I}, where g fi represents the i-th carrier frequency data frame group in G f .

[0041] Because the communication demodulation end needs to sort the demodulated data frame groups in sequence, the sequence information i needs to be represented by a Q-bit binary number d i , so the binary number d i representing the sequence is added to the end of each data frame group.

[0042] (4b) Represent all the binary bit data in each carrier frequency data frame group g f in G fi as a decimal number to obtain the set of carrier frequency decimal numbers where, represents the i-th carrier frequency decimal number in

[0043] (4c) Select I carriers from the L carriers F whose sequences correspond to each in as the carrier frequencies of the I frequency modulation slope mismatch interference signals.

[0044] Step 5) Obtain the interfering communication integrated waveform:

[0045] According to the obtained frequency modulation slope of the frequency modulation slope mismatch interference signal and the carrier frequency of each frequency modulation slope mismatch interference signal, use a signal generator to generate I frequency modulation slope mismatch interference signals and superimpose them at the transmitting end to obtain the interfering communication integrated waveform s(t):

[0046]

[0047] where, and respectively represent the carrier frequency and the frequency modulation slope of the frequency modulation slope mismatch interference signal.

[0048] The carrier frequency of each generated frequency modulation slope mismatch interference signal maps 2Q-bit data, where the first Q bits represent the binary data to be transmitted, and the last Q-bit data is additionally added to distinguish the order of the I group of data frames. The communication demodulation end first performs de-slanting processing on the integrated waveform according to the frequency modulation slope in U to obtain I single-carrier signals with different carrier frequencies, then obtains I single-carrier values through fast Fourier transform, and obtains the 2Q-bit data of each data frame group according to the mapping relationship between the carrier frequency and the 2Q-bit data. Then, according to the magnitude of the last Q-bit data of each data frame group, the first Q-bit data of the I data frame groups are sorted from small to large to obtain the communication information represented by the carrier frequency. By simultaneously transmitting multiple frequency modulation slope mismatch interference signals carrying communication information, the number of communication bits transmitted within the radar signal duration is increased, thereby improving the communication rate.

[0049] The following combines simulation experiments to illustrate the technical effects of the present invention.

[0050] 1. Simulation conditions and content:

[0051] Software environment: Matlab R2020b simulation software under the Inter(R)core(TM)i7-11700F CPU@2.50GHz, Windows10 Home Chinese Edition 64-bit operating system.

[0052] The radar signal used in the simulation is a linear frequency modulation signal, the radar signal duration T = 20us, the radar signal frequency modulation slope μ = 1×10 12 Hz / s, the radar signal carrier frequency f = 0GHz, the sampling frequency f s = 10MHz, the frequency modulation slope set U = {7×10 11 , 7.5×10 11}Hz / s, the carrier frequency set F = {0, f s / 128,…, 63f s / 128}.

[0053] Table 1 lists the specific values obtained according to the communication data division rules under the above parameter design.

[0054] Frequency modulation slope K 2 Number of bits Q 3 Frequency modulation slope interval Δμ <![CDATA[5×10 10 Hz / s]]> Data frame group I 8 Frequency modulation slope interval Δf 78.125KHz Number of bits M 1 Number of communication bits N 25 ～ ～

[0055] Table 1 Specific values

[0056] The communication rate of the present invention and the prior art is simulated, and the results are as Figure 2 shown;

[0057] 2. Analysis of simulation results:

[0058] Referring to Figure 2 , the abscissa in the figure represents the number of bits Q, and the ordinate represents the communication rate of the integrated waveform. The variation range of the abscissa is [1, 4], and the variation range of the ordinate is [0.1, 3.25] M·Symbol·s -1 . It can be seen from the figure that as the number of bits Q gradually increases, the communication rate also gradually increases. When the number of bits Q is the same, the communication rate of the present invention is faster than that of the prior art, and the difference in communication rate gradually increases as the number of bits Q increases.

[0059] In summary, the communication rate of the integrated waveform proposed by the present invention can reach M·Symbol·s -1 , and it can carry more communication bit information per unit time. Therefore, the communication rate is better than that of the existing integrated waveform.

Claims

1. A method for generating an integrated waveform for interference communication based on frequency modulation slope mismatch interference, characterized in that It includes the following steps: (1) Initialize parameters: Initialize that the duration, frequency modulation slope, and carrier frequency of the linear frequency modulation signal r(t) of the radar are T, μ, and f respectively, and the sampling frequency of the communication end is f s , K frequency modulation slopes with an interval of Δμ and increasing values in sequence U = {μ k | 1 ≤ k ≤ K}, L carrier frequencies with an interval of Δf and increasing values in sequence F = {f l | 1 ≤ l ≤ L}, where K = 2 M , M is the number of binary bits that the K frequency modulation slopes in U can map, M ≥ 1, L = 2 J , J is the number of binary bits that the L carrier frequencies in F can map, J ≥ 2 and is an even number, μ k represents the k-th frequency modulation slope, f l represents the l-th carrier frequency, t represents the fast time, t0 ≤ t ≤ t0 + T, t0 is the starting time of r(t), the sampling frequency f s , the frequency modulation slope μ k , the carrier frequency f l , the frequency modulation slope μ of r(t), and the carrier frequency f of r(t) need to satisfy the following relationships: (2) Divide the binary bit data to be sent: Select the first M - bit binary bit data from the data frame S to be sent, which includes N - bit binary bit data, to form the data frame S1 = {s m | 1 ≤ m ≤ M}, and evenly divide the remaining N - M - bit binary bit data into I groups to obtain the data frame group set G = {g i | 1 ≤ i ≤ I}, where g i = {s iq | 1 ≤ q ≤ Q}. Here, s m represents the m - th binary bit data in S1, g i represents the i - th data frame group in G that contains Q - bit binary bit data, and s iq represents the q - th binary bit data in g i . Also, N = M + I×Q, I = 2 Q , Q = J2; (3) Obtain the frequency modulation slope of the frequency modulation slope mismatch interference signal: Represent the data frame S1 as a decimal number d S1 , and select the frequency modulation slope corresponding to the order selected from the K frequency modulation slopes U and d S1 as the frequency modulation slope of the frequency modulation slope mismatch interference signal; (4) Obtain the carrier frequency of the frequency modulation slope mismatch interference signal: (4a) Represent the order i in g i as a Q-bit binary number d i , and add d i to the end of the data frame group g i to obtain the set of carrier frequency data frame groups G corresponding to the set of data frame groups G f = {g fi | 1 ≤ i ≤ I}, where g fi represents the i-th carrier frequency data frame group in G f ; (4b) Represent each carrier frequency data frame group g f in G fi as a decimal number for all the binary bit data, obtaining a set of carrier frequency decimal numbers where represents the i-th carrier frequency decimal number in (4c) Select I carrier frequencies from L carrier frequencies F in the order corresponding to each in as the carrier frequencies of the I frequency modulation slope mismatch interference signals; ​ (5) Obtain the integrated waveform of interference communication: According to the obtained frequency modulation slope of the frequency modulation slope mismatch interference signal and the carrier frequency of each frequency modulation slope mismatch interference signal, use a signal generator to generate I frequency modulation slope mismatch interference signals and superimpose them at the transmitting end to obtain the integrated waveform s(t) of interference communication.

2. The interference communication integrated waveform generation method based on frequency modulation slope mismatch interference according to claim 1, wherein For the radar signal r(t) described in step (1), its expression is: where rect(·) represents the rectangular window function, exp(·) represents the exponential function, and j represents the imaginary unit.

3. The interference communication integrated waveform generation method based on the interference of FM slope mismatch according to claim 2, characterized in that For the integrated waveform s(t) described in step (5), its expression is: Among them, and respectively represent the carrier frequency and the frequency modulation slope of the frequency modulation slope mismatch interference signal.

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