A method and system for designing frequency-hopping sequences based on an improved combined jump random shift method.

Abstract

This invention discloses a frequency hopping sequence design method and system based on an improved combined hopping random translation method. Specifically, it involves: setting and configuring the parameters and initial values ​​of the frequency hopping communication system; performing chaotic iteration on each track, dynamically calculating LogSC mapping control parameters based on the current state value of the Tent track; normalizing and quantizing the main track state to obtain the fixed-point values ​​of each track; dynamically extracting the bits from the fixed-point values ​​of each track to obtain binary strings for each track; arranging the binary strings of each track row-wise to construct a matrix; performing XOR and modulo operations on the matrix column-wise to obtain two candidate frequency hopping symbols; and performing adaptive switching to select the track and wide-interval recursive processing to obtain the final frequency hopping symbol. This invention enhances the randomness and unpredictability of the frequency hopping sequence, improves the multiple access capacity, security against interception, and anti-interference robustness of the frequency hopping communication system, and enhances the security of the frequency hopping communication system.

Description

Technical Field

[0001] This invention relates to the field of frequency hopping communication technology in wireless communication technology, and in particular to a frequency hopping sequence design method and system based on an improved combined hopping random shift method. Background Technology

[0002] Frequency hopping communication is a communication method that uses a set of pseudo-random sequences to control the random hopping of the carrier frequency. It has the characteristics of anti-interference, anti-interception, code division multiple access, and frequency band sharing, and therefore has been widely used in modern military communications and civilian mobile communications.

[0003] Chaotic frequency-hopping sequences are a common type of frequency-hopping sequence. They are obtained by quantizing chaotic time series generated through chaotic system mapping. Currently, chaotic mappings that generate chaotic time series include Tent, Logistic mapping, and improved Logistic mapping.

[0004] Wide-gap chaotic frequency-hopping sequences improve the anti-interference performance of frequency-hopping communication systems by wide-gap processing of traditional chaotic frequency-hopping sequences, making the adjacent frequency gaps of the sequence larger than a fixed threshold. An ideal frequency-hopping sequence should have good balance, meaning that the frequency of each frequency should be as uniform as possible within a complete cycle. The Random Shift Replace method (RSR) uses chaotic sequences as the object, shifting some "narrow points" to achieve a wide gap. The Combined Hopping Random Shift method (CHRS) employs an improved Logistic mapping method, utilizing the sensitive dependence of chaotic systems on initial conditions to generate numerous signals. It combines two chaotic frequency-hopping sequences and uses the resulting combined sequence to perform a wide-gap mapping on the target chaotic frequency-hopping sequence.

[0005] An ideal frequency-hopping sequence should have good balance, meaning that the frequency of each frequency should occur as evenly as possible within a complete cycle. The RSR wide-interval design method shifts the "narrow points" in the chaotic frequency-hopping sequence to achieve a wide interval, but this reduces the balance of the original sequence. The Hamming cross-correlation improvement of the wide-interval sequence constructed by the CHRS method is relatively small compared to the RSR method when the sequence length is below 500. In code division multiple access systems, different users are assigned different frequency-hopping sequences, leading to a higher probability of frequency collisions under certain time delays. Summary of the Invention

[0006] The purpose of this invention is to provide a frequency hopping sequence design method and system that features uniform frequency slot distribution, strong Hamming correlation, high complexity, and strong anti-interference capability.

[0007] The technical solution to achieve the purpose of this invention is: a frequency hopping sequence design method based on an improved combined jump random shift method, comprising the following steps:

[0008] Step 1: Set the parameters and configure the initial values ​​for the frequency hopping communication system;

[0009] Step 2: Perform chaotic iterations of the main orbit, Tent orbit, and Logistic orbit;

[0010] Step 3: Dynamically calculate the LogSC mapping control parameters based on the current state value of the Tent orbit;

[0011] Step 4: Normalize the main orbit state and perform 32-bit fixed-point quantization to obtain the fixed-point values ​​of the main orbit, Tent orbit, and Logistic orbit.

[0012] Step 5: Perform dynamic bit extraction of the fixed-point values ​​of the main track, Tent track, and Logistic track to obtain the binary strings of the main track, Tent track, and Logistic track.

[0013] Step 6: Arrange the binary strings of the main track, Tent track, and Logistic track by row to construct a matrix. Perform XOR and modulo operations on the matrix column by column to obtain two candidate frequency hopping symbols.

[0014] Step 7: Perform adaptive switching selection of tracks and wide-interval recursive processing to generate the final frequency hopping symbols.

[0015] Furthermore, the parameter setting and initial value configuration of the frequency hopping communication system described in step 1 are as follows:

[0016] Step 1.1: Select all parameters for the frequency hopping communication system, including the number of frequency hopping slots. Sequence length Minimum frequency hopping interval Fixed-point bit width LosSC mapping baseline control parameters Disturbance amplitude Offset Extraction length variation range and basic extraction length ;set up This represents the modulo operation. Indicates rounding down to the nearest integer; where the fixed-point bit width is... Set to 32-bit;

[0017] Step 1.2: Set three independent initial values ​​that take values ​​in the open interval (0,1): Initial value of the main track. Used for LosSC chaotic mapping and Tent auxiliary orbit initial values Initial values ​​of Logistic auxiliary orbit ;

[0018] Step 1.3: Calculate intermediate parameters:

[0019]

[0020]

[0021] Since the intermediate parameters remain constant throughout the sequence generation process, they are pre-computed to reduce computational overhead.

[0022] Furthermore, the chaotic iteration of the main orbit, Tent orbit, and Logistic orbit described in step 2 is as follows:

[0023] Step 2.1: Initialization of the Iterative Process

[0024] Set iteration index This indicates that the current iteration is the first iteration, and the current state variable is initialized. The main track state variable is set to... Set as , Tent auxiliary orbit state variables Set as Logistic auxiliary orbital state variables Set as ;

[0025] Step 2.2, Chaotic Iteration of the Auxiliary Track;

[0026] (1) Iterative update of Tent mapping:

[0027]

[0028] (2) Logistc mapping iterative update:

[0029]

[0030] The above formula ensures that the iteration value always remains at Within the interval, parameter 4 is chosen because it is located in the chaotic region of the Logistic mapping and can generate non-periodic trajectories.

[0031] Step 2.3, Main track LogSC chaotic iteration:

[0032]

[0033] The above formula incorporates the Logistic mapping term. sine term And the outer cosine function, through dynamic parameter control. Adjust the weight ratio of the two items, and then introduce an offset. .

[0034] Furthermore, the dynamic calculation of the LogSC mapping control parameters based on the current state value of the Tent orbit in step 3 is as follows:

[0035] Step 3.1: Based on the current state value of the Tent orbit Dynamic calculation of the first LogSC mapping control parameters for the next iteration:

[0036]

[0037] in Will from Range mapping to The interval makes able to Bidirectional fluctuations within the central range, with fluctuation amplitude ranging from control;

[0038] Step 3.2: To ensure the stability and chaotic characteristics of the system, the calculated... Limiting This helps avoid system degradation or divergence caused by parameters going out of bounds.

[0039] Furthermore, step 4 involves normalizing the main orbital state and performing 32-bit fixed-point quantization to obtain the fixed-point values ​​of the main orbital, Tent orbital, and Logistic orbital, as detailed below:

[0040] Step 4.1, Normalize the main orbital values:

[0041]

[0042] Because the output range of LogSC mapping is The main track status value needs to be... Mapping to Standard interval;

[0043] Step 4.2: Fixed-point quantization processing;

[0044] The normalized continuous values ​​are converted into 32-bit unsigned integers and then subjected to fixed-point quantization.

[0045] Main orbital positioning value:

[0046]

[0047] Tent orbital localization values:

[0048]

[0049] Logistic orbital fixed-point values:

[0050]

[0051] Will Interval linear mapping to Integer range; the binary representations of these three fixed-point integer values ​​will serve as the raw data source for subsequent bit extraction operations.

[0052] Further, step 5 involves dynamically extracting the fixed-point values ​​of the main orbital, Tent orbital, and Logistic orbital to obtain the binary strings of the main orbital, Tent orbital, and Logistic orbital, as detailed below:

[0053] Step 5.1: Extract the starting position and calculate.

[0054] Based on the current state value of the Logistic orbit The starting position for bit extraction is dynamically determined:

[0055]

[0056] The above formula is first calculated To obtain the number of available starting positions, by... Multiply by it and round down to get the preliminary index, then... Modulo operation ensures the index is within a valid range, and finally, addition... Convert to based The index ensures that from Start extracting bits The number of bits will not exceed the 32-bit boundary;

[0057] Step 5.2, Calculation of extraction length

[0058] Based on the current state of the Tent orbit The actual extraction length for this iteration is dynamically determined:

[0059]

[0060] The above formula uses the basic length Based on, through Will from Mapped to To increase the magnitude of change, multiply by And round down to the nearest integer. Take the modulus to obtain The offset within the range makes the final extraction length exist Changes within the interval;

[0061] Step 5.3, Multi-track dynamic position extraction operation

[0062] From three 32-bit fixed-point Dynamic bit extraction is performed in the binary representation, treating each integer as a 32-bit binary string arranged from the most significant bit to the least significant bit, starting from the... Continuous sampling from position 1 The bits are used to obtain three lengths of each. binary string: , , .

[0063] Further, in step 6, the binary strings of the main track, Tent track, and Logistic track are arranged row by row to construct a matrix. XOR and modulo operations are then performed on the matrix column by column to obtain two candidate frequency hopping symbols, as detailed below:

[0064] Step 6.1: Arrange the binary strings of the main orbital, Tent orbital, and Logistic orbital row by row to construct a... Bit matrix :

[0065]

[0066] Step 6.2: XOR and Modulo operations;

[0067] For matrix Perform an XOR operation column-wise, XORing the three bits of each column to obtain two pairs of lengths. The binary numbers are converted to decimal integers, and then the total number of frequency hopping slots is calculated separately. Taking the modulus, we obtain two candidate frequency hopping symbols:

[0068]

[0069]

[0070] Furthermore, step 7, which involves adaptive switching selection of tracks and wide-interval recursive processing to generate the final frequency hopping symbols, is detailed as follows:

[0071] Step 7.1: Adaptively switch to select a track;

[0072] Based on the current state value of the Logistic orbit In two candidate frequency hopping symbols and Adaptive selection is performed between these sequences, using a sawtooth perturbation selection sequence. Used to control the generation of subsequent sequences. The expression is as follows:

[0073]

[0074] Three-combination jump control sequence It is a combined sequence, based on the selected sequence. The value of is used to switch between two different sequences. The expression is as follows:

[0075]

[0076] Step 7.2: Main track mold taking preprocessing;

[0077] Modular operation on the fixed-point values ​​of the main track:

[0078]

[0079] Will Mapped to frequency hopping slot range Internally, it serves as the base value for recursive calculations;

[0080] Step 7.3, Frequency hopping symbol generation operation:

[0081]

[0082] When the number of iterations When the first frequency hopping symbol directly takes the modulus value of the main track; when the iteration number... At that time, a wide-interval recursive formula is used to generate frequency hopping symbols.

[0083] A frequency hopping sequence design system based on an improved combined hopping random shift method, the system being used to implement the aforementioned frequency hopping sequence design method, the system comprising:

[0084] The parameter setting and initial value configuration module is used to set and configure the parameters of the frequency hopping communication system.

[0085] The chaos iteration module is used for chaotic iteration of the main orbit, the Tent orbit, and the Logistic orbit;

[0086] The mapping control parameter calculation module dynamically calculates the LogSC mapping control parameters based on the current state value of the Tent orbit.

[0087] The normalization and quantization processing module performs normalization processing and 32-bit fixed-point quantization processing on the main orbit state to obtain the fixed-point values ​​of the main orbit, Tent orbit, and Logistic orbit.

[0088] The dynamic bit extraction module performs dynamic bit extraction of the fixed-point values ​​of the main track, Tent track, and Logistic track to obtain the binary strings of the main track, Tent track, and Logistic track.

[0089] The matrix construction module arranges the binary strings of the main track, Tent track, and Logistic track in rows to construct a matrix. It then performs XOR and modulo operations on the matrix column by column to obtain two candidate frequency hopping symbols.

[0090] The frequency hopping symbol generation module performs adaptive switching selection of tracks and wide-interval recursive processing to generate the final frequency hopping symbol.

[0091] A computer device includes a memory and a processor, the memory and the processor being communicatively connected to each other, the memory storing computer instructions, and the processor executing the frequency hopping sequence design method by executing the computer instructions.

[0092] Compared with the prior art, the present invention has the following significant advantages: (1) It introduces the LogSC chaotic mapping, which currently has high dynamic complexity, into a new frequency hopping sequence design framework. Through simulation verification, the approximate entropy of the generated wide-interval chaotic frequency hopping sequence is improved compared with CHRS at different sequence lengths, significantly enhancing the randomness and unpredictability of the sequence; (2) It adopts a dual-auxiliary chaotic orbit composed of Tent mapping and Logistic mapping to realize real-time perturbation of the parameters of the main chaotic system and the bit extraction position throughout the entire process. This multi-orbit cooperative mechanism makes the system sensitive to the initial value reach (2) With a magnitude of 100,000, the output of completely different sequences can be achieved with slight differences in initial conditions, which improves the multiple access capacity, security and anti-interception, and anti-interference robustness of the frequency hopping communication system; (3) The multi-track bit-level nonlinear fusion technology of column XOR is used to process the chaotic sequence. The nonlinear correlation between bits is enhanced by column XOR operation, which reduces the risk of short period phenomenon and linear correlation that may exist in traditional methods and improves the security of frequency hopping communication system. Attached Figure Description

[0093] Figure 1 This is a flowchart of a frequency hopping sequence design method based on an improved combined jump random translation method according to the present invention.

[0094] Figure 2 This is a comparison chart of the balance of frequency hopping sequences generated using three different methods in this embodiment of the invention.

[0095] Figure 3 This is a comparison chart of the approximate entropy of frequency hopping sequences generated using three different methods in this embodiment of the invention.

[0096] Figure 4 This is a comparison diagram of Hamming autocorrelation of frequency hopping sequences generated using three different methods in this embodiment of the invention.

[0097] Figure 5 This is a graph showing the relationship between the sequence length and the frequency difference of a wide-interval chaotic frequency-hopping sequence generated using the ICHRS method in an embodiment of the present invention. Detailed Implementation

[0098] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0099] like Figure 1 As shown, the present invention provides a frequency hopping sequence design method based on an improved combined jump random shift method, comprising the following steps:

[0100] Step 1: Set the parameters and configure the initial values ​​for the frequency hopping communication system, as follows:

[0101] Step 1.1: Select all parameters for the frequency hopping communication system, including the number of frequency hopping slots. Sequence length Minimum frequency hopping interval Fixed-point bit width LosSC mapping baseline control parameters Disturbance amplitude Offset Extraction length variation range and basic extraction length ;set up This represents the modulo operation. Indicates rounding down to the nearest integer; where the fixed-point bit width is... It is preferable to set it to 32 bits to ensure sufficient calculation accuracy;

[0102] Step 1.2: Set three independent initial values ​​that take values ​​in the open interval (0,1): Initial value of the main track. Used for LosSC chaotic mapping and Tent auxiliary orbit initial values Initial values ​​of Logistic auxiliary orbit ;

[0103] Step 1.3: Calculate intermediate parameters:

[0104]

[0105]

[0106] Since the intermediate parameters remain constant throughout the sequence generation process, they can be pre-computed to reduce computational overhead.

[0107] Step 2: Perform chaotic iterations of the main orbit, Tent orbit, and Logistic orbit, as follows:

[0108] Step 2.1: Initialization of the Iterative Process

[0109] Set iteration index This indicates that the current iteration is the first iteration, and the current state variable is initialized. The main track state variable is set to... Set as , Tent auxiliary orbit state variables Set as Logistic auxiliary orbital state variables Set as ;

[0110] Step 2.2, Chaotic Iteration of the Auxiliary Track

[0111] (1) Iterative update of Tent mapping

[0112]

[0113] This mapping exhibits a "tent"-shaped structure, with good ergodicity and uniformity, and can provide a high-quality source of randomness for the system;

[0114] (2) Logistc mapping iterative update

[0115]

[0116] The above formula ensures that the iteration value always remains at Within the interval, parameter 4 is chosen because this value is located in the chaotic region of the Logistic map, which can generate complex non-periodic trajectories.

[0117] Step 2.3: Main track LogSC chaotic iteration

[0118]

[0119] This mapping incorporates Logistic mapping terms. sine term And the outer cosine function, through dynamic parameter control. Adjust the weight ratio of the two items, and then introduce an offset. .

[0120] Step 3: Based on the current state value of the Tent orbit, dynamically calculate the LogSC mapping control parameters, as follows:

[0121] Step 3.1: Based on the current state value of the Tent orbit Dynamic calculation of the first LogSC mapping control parameters for the next iteration:

[0122]

[0123] in Will from Range mapping to The interval makes able to Bidirectional fluctuations within the central range, with fluctuation amplitude ranging from control;

[0124] Step 3.2: To ensure the stability and chaotic characteristics of the system, the calculated... Limiting This avoids system degradation or divergence caused by parameters going out of bounds, and enhances the complexity and unpredictability of chaotic systems.

[0125] Step 4: Normalize and perform 32-bit fixed-point quantization on the main orbital state to obtain the fixed-point values ​​of the main orbital, Tent orbital, and Logistic orbital, as follows:

[0126] Step 4.1, Normalize the main orbital values:

[0127]

[0128] Because the output range of LogSC mapping is The main track status value needs to be... Mapping to Standard interval;

[0129] Step 4.2, Fixed-point quantization processing

[0130] The normalized continuous values ​​are converted into 32-bit unsigned integers and then subjected to fixed-point quantization.

[0131] Main orbital positioning value:

[0132]

[0133] Tent orbital localization values:

[0134]

[0135] Logistic orbital fixed-point values:

[0136]

[0137] Will Interval linear mapping to The integer range ensures full utilization of the 32-bit representation precision; the binary representations of these three fixed-point integer values ​​will serve as the raw data source for subsequent bit extraction operations.

[0138] Step 5: Perform dynamic bit extraction on the fixed-point values ​​of the main orbital, Tent orbital, and Logistic orbital to obtain the binary strings of the main orbital, Tent orbital, and Logistic orbital, as follows:

[0139] Step 5.1: Extract the starting position and calculate.

[0140] Based on the current state value of the Logistic orbit The starting position for bit extraction is dynamically determined:

[0141]

[0142] The above formula is first calculated To obtain the number of available starting positions, by... Multiply by it and round down to get the preliminary index, then... Modulo operation ensures the index is within a valid range, and finally, addition... Convert to based The index ensures that from Start extracting bits The number of bits will not exceed the 32-bit boundary;

[0143] Step 5.2, Calculation of extraction length

[0144] Based on the current state of the Tent orbit The actual extraction length for this iteration is dynamically determined:

[0145]

[0146] The above formula uses the basic length Based on, through Will from Mapped to To increase the magnitude of change, multiply by And round down to the nearest integer. Take the modulus to obtain The offset within the range makes the final extraction length exist Variation within the interval; this dynamic length mechanism enhances the unpredictability of sequence generation;

[0147] Step 5.3, Multi-track dynamic position extraction operation

[0148] From three 32-bit fixed-point Dynamic bit extraction is performed in the binary representation, treating each integer as a 32-bit binary string arranged from the most significant bit to the least significant bit, starting from the... Continuous sampling from position 1 The bits are used to obtain three lengths of each. binary string: , , .

[0149] Step 6: Arrange the binary strings of the main track, Tent track, and Logistic track by row to construct a matrix. Perform XOR and modulo operations on the matrix column by column to obtain two candidate frequency hopping symbols, as follows:

[0150] Step 6.1: Arrange the binary strings of the main orbital, Tent orbital, and Logistic orbital row by row to construct a... Bit matrix :

[0151]

[0152] Step 6.2, XOR and Modulo Operations

[0153] For matrix Perform an XOR operation column-wise, XORing the three bits of each column to obtain two pairs of lengths. The binary numbers are converted to decimal integers, and then the total number of frequency hopping slots is calculated separately. Taking the modulus, we obtain two candidate frequency hopping symbols:

[0154]

[0155]

[0156] Step 7: Perform adaptive switching selection of tracks and wide-interval recursive processing to generate the final frequency hopping symbols, as follows:

[0157] Step 7.1: Adaptive switching of track selection

[0158] Based on the current state value of the Logistic orbit In two candidate frequency hopping symbols and Adaptive selection is performed between these sequences, using a sawtooth perturbation selection sequence. Used to control the generation of subsequent sequences. The expression is as follows:

[0159]

[0160] Three-combination jump control sequence It is a combined sequence, based on the selected sequence. The value of is used to switch between two different sequences. The expression is as follows:

[0161]

[0162] Step 7.2, Main track mold taking preprocessing

[0163] Modular operation on the fixed-point values ​​of the main track:

[0164]

[0165] Will Mapped to frequency hopping slot range Internally, it serves as the base value for recursive calculations;

[0166] Step 7.3, Frequency hopping symbol generation operation:

[0167]

[0168] When the number of iterations When the first frequency hopping symbol directly takes the modulus value of the main track; when the iteration number... At that time, a wide-interval recursive formula is used to generate frequency hopping symbols.

[0169] This invention also provides a frequency hopping sequence design system based on an improved combined hopping random shift method. This system is used to implement the aforementioned frequency hopping sequence design method, and the system includes:

[0170] The parameter setting and initial value configuration module is used to set and configure the parameters of the frequency hopping communication system.

[0171] The chaos iteration module is used for chaotic iteration of the main orbit, the Tent orbit, and the Logistic orbit;

[0172] The mapping control parameter calculation module dynamically calculates the LogSC mapping control parameters based on the current state value of the Tent orbit.

[0173] The normalization and quantization processing module performs normalization processing and 32-bit fixed-point quantization processing on the main orbit state to obtain the fixed-point values ​​of the main orbit, Tent orbit, and Logistic orbit.

[0174] The dynamic bit extraction module performs dynamic bit extraction of the fixed-point values ​​of the main track, Tent track, and Logistic track to obtain the binary strings of the main track, Tent track, and Logistic track.

[0175] The matrix construction module arranges the binary strings of the main track, Tent track, and Logistic track in rows to construct a matrix. It then performs XOR and modulo operations on the matrix column by column to obtain two candidate frequency hopping symbols.

[0176] The frequency hopping symbol generation module performs adaptive switching selection of tracks and wide-interval recursive processing to generate the final frequency hopping symbol.

[0177] The present invention also provides a computer device, comprising: a memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the frequency hopping sequence design method by executing the computer instructions.

[0178] Example

[0179] This embodiment provides a frequency hopping sequence design method based on an improved combined jump random shift method. The simulation input parameters are shown in Table 1.

[0180] Table 1 Simulation parameter settings for generating frequency hopping sequences

[0181]

[0182] The method of this invention is used to design wide-interval chaotic frequency hopping sequences, and the performance of the designed wide-interval chaotic frequency hopping sequences is analyzed, as follows:

[0183] 1. Balance

[0184] An ideal frequency-hopping sequence should have good balance, meaning that the frequencies of each frequency appear as evenly as possible within a complete cycle. Balance characterizes the frequency gap distribution properties of the sequence, and its expression is defined as follows:

[0185]

[0186] in, For the first The number of times each slot appears in the sequence. The smaller the value, the better the sequence balance performance.

[0187] In the experiment, the number of frequency slots was 32, and different sequence lengths were used. Calculate its equilibrium characteristic parameters , Figure 2 A comparison of the balance of frequency-hopping sequences generated by three different methods is shown in the figure. It can be seen from the figure that the balance of the frequency-hopping sequences generated by the CHSR method and the ICHRS method of this invention is better than that of the RSR method. When the sequence length is greater than 2000, the wide-interval chaotic frequency-hopping sequence constructed by the ICHRS method of this invention... Smaller, resulting in better balance in the generated frequency hopping sequence.

[0188] 2. Complexity

[0189] Time series approximate entropy measures the complexity and irregularity of a sequence. The higher the approximate entropy, the more complex and unpredictable the sequence. For a sequence of length... sequence The derivation of the approximate entropy expression is as follows:

[0190] (1) Reconstruct Group sequence:

[0191]

[0192] (2) Define the sequence with sequence Chebyshev distance , is the maximum value among the differences between corresponding elements in the two sequences:

[0193]

[0194] (3) Set the threshold for similarity comparison For each Statistical satisfaction The number, and the total distance. The ratio is denoted as:

[0195]

[0196] (4) Take the logarithm, then the average, and denote it as:

[0197]

[0198] (5) Increase the dimension by 1. Repeat steps (1) to (4) to obtain and ;

[0199] (6) The approximate entropy of this sequence is:

[0200]

[0201] The approximate entropy of the wide-spaced chaotic frequency-hopping sequence generated by the RSR method, the CHSR method, and the ICHRS method of this invention is as follows: Figure 3 As shown, the ICHRS method of this invention has improved complexity compared to the RSR and CHSR methods. The ICHRS method of this invention generates frequency hopping sequences with higher complexity for different sequence lengths.

[0202] 3. Hamming correlation

[0203] Hamming correlation of frequency hopping sequences is an indicator that measures the "frequency collision" between two frequency hopping sequences under different relative time delays, and directly determines the severity of multiple access interference and self-interference.

[0204] Let the size of the frequency set be The sequence period is Frequency hopping sequence , The normalized Hamming autocorrelation parameter is defined as follows:

[0205]

[0206] The normalized Hamming cross-correlation parameter is defined as follows:

[0207]

[0208] in,

[0209]

[0210]

[0211] Hamming autocorrelation of wide-spaced chaotic frequency-hopping sequences generated by the RSR method, CHSR method, and the ICHRS method of this invention is as follows: Figure 4 As shown, the wide-interval chaotic frequency-hopping sequence constructed by the ICHRS method of this invention has better Hamming autocorrelation.

[0212] 4. Wide spacing characteristics

[0213] The frequency hopping width spacing characteristic requires that the frequency spacing between adjacent frequency hopping time slots in the sequence be no less than a given threshold. The average frequency hopping interval is defined as follows:

[0214]

[0215] The average frequency hopping interval of the wide-interval chaotic frequency hopping sequences generated by the RSR method, CHSR method and the ICHRS method of this invention is shown in Table 2. The wide-interval characteristics of the wide-interval chaotic frequency hopping sequences generated by the ICHRS method are worse than those of the RSR method and CHSR method, but still meet the frequency interval requirements.

[0216] Table 2. Wide-spacing characteristics of frequency hopping sequences

[0217]

[0218] 5. Initial value sensitivity

[0219] like Figure 5 As shown, the wide-interval chaotic frequency-hopping sequence generated by the ICHRS method of this invention still retains the most essential "initial value sensitivity" of chaotic systems: even if the difference between two iterations is only a few degrees... With a small initial value, after more than ten to dozens of mappings, the resulting frequency hopping sequence trajectories will quickly separate, the cross-correlation peaks will approach zero, and they will present two statistically independent sequences.

[0220] In summary, the frequency hopping sequence design method based on the improved combined hopping random translation method of this invention achieves a comprehensive performance improvement of wide-interval chaotic frequency hopping sequences, further enhances the uniform distribution characteristics of the frequency slots of the sequence, thereby improving the anti-interference capability of the frequency hopping sequence, making the carrier of the frequency hopping communication system less prone to leakage, improving the Hamming correlation and complexity of the sequence, and enhancing the security of the frequency hopping communication system.

[0221] The above are merely preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for designing frequency hopping sequences based on an improved combined jump random shift method, characterized in that, Includes the following steps: Step 1: Set the parameters and configure the initial values ​​for the frequency hopping communication system; Step 2: Perform chaotic iterations of the main orbit, Tent orbit, and Logistic orbit; Step 3: Dynamically calculate the LogSC mapping control parameters based on the current state value of the Tent orbit; Step 4: Normalize the main orbit state and perform 32-bit fixed-point quantization to obtain the fixed-point values ​​of the main orbit, Tent orbit, and Logistic orbit. Step 5: Perform dynamic bit extraction of the fixed-point values ​​of the main track, Tent track, and Logistic track to obtain the binary strings of the main track, Tent track, and Logistic track. Step 6: Arrange the binary strings of the main track, Tent track, and Logistic track by row to construct a matrix. Perform XOR and modulo operations on the matrix column by column to obtain two candidate frequency hopping symbols. Step 7: Perform adaptive switching selection of tracks and wide-interval recursive processing to generate the final frequency hopping symbols.

2. The frequency hopping sequence design method based on the improved combined jump random shift method according to claim 1, characterized in that, Step 1, which involves setting and configuring the parameters and initial values ​​of the frequency hopping communication system, is as follows: Step 1.1: Select all parameters for the frequency hopping communication system, including the number of frequency hopping slots. Sequence length Minimum frequency hopping interval Fixed-point bit width LosSC mapping baseline control parameters Disturbance amplitude Offset Extraction length variation range and basic extraction length ;set up This represents the modulo operation. Indicates rounding down to the nearest integer; where the fixed-point bit width is... Set to 32-bit; Step 1.2: Set three independent initial values ​​that take values ​​in the open interval (0,1): Initial value of the main track. Used for LosSC chaotic mapping and Tent auxiliary orbit initial values Initial values ​​of Logistic auxiliary orbit ; Step 1.3: Calculate intermediate parameters: Since the intermediate parameters remain constant throughout the sequence generation process, they are pre-computed to reduce computational overhead.

3. The frequency hopping sequence design method based on the improved combined jump random shift method according to claim 1, characterized in that, Step 2, which involves chaotic iteration of the main orbit, Tent orbit, and Logistic orbit, is detailed below: Step 2.1: Initialization of the Iterative Process Set iteration index This indicates that the current iteration is the first iteration, and the current state variable is initialized. The main track state variable is set to... Set as , Tent auxiliary orbit state variables Set as Logistic auxiliary orbital state variables Set as ; Step 2.2, Chaotic Iteration of the Auxiliary Track; (1) Iterative update of Tent mapping: (2) Logistc mapping iterative update: The above formula ensures that the iteration value always remains at Within the interval, parameter 4 is chosen because it is located in the chaotic region of the Logistic mapping and can generate non-periodic trajectories. Step 2.3, Main track LogSC chaotic iteration: The above formula incorporates the Logistic mapping term. sine term And the outer cosine function, through dynamic parameter control. Adjust the weight ratio of the two items, and then introduce an offset. .

4. The frequency hopping sequence design method based on the improved combined jump random translation method according to claim 1, characterized in that, Step 3, which involves dynamically calculating the LogSC mapping control parameters based on the current state value of the Tent orbit, is as follows: Step 3.1: Based on the current state value of the Tent orbit Dynamic calculation of the first LogSC mapping control parameters for the next iteration: in Will from Range mapping to The interval makes able to Bidirectional fluctuations within the central range, with fluctuation amplitude ranging from control; Step 3.2: To ensure the stability and chaotic characteristics of the system, the calculated... Limiting This helps avoid system degradation or divergence caused by parameters going out of bounds.

5. The frequency hopping sequence design method based on the improved combined jump random shift method according to claim 1, characterized in that, Step 4 involves normalizing the main orbital state and performing 32-bit fixed-point quantization to obtain the fixed-point values ​​of the main orbital, Tent orbital, and Logistic orbital, as detailed below: Step 4.1, Normalize the main orbital values: Because the output range of LogSC mapping is The main track status value needs to be... Mapping to Standard interval; Step 4.2: Fixed-point quantization processing; The normalized continuous values ​​are converted into 32-bit unsigned integers and then subjected to fixed-point quantization. Main orbital positioning value: Tent orbital localization values: Logistic orbital fixed-point values: Will Interval linear mapping to Integer range; the binary representations of these three fixed-point integer values ​​will serve as the raw data source for subsequent bit extraction operations.

6. The frequency hopping sequence design method based on the improved combined jump random shift method according to claim 1, characterized in that, Step 5 involves dynamically extracting the fixed-point values ​​of the main orbital, Tent orbital, and Logistic orbital to obtain the binary strings of the main orbital, Tent orbital, and Logistic orbital, as detailed below: Step 5.1: Extract the starting position and calculate. Based on the current state value of the Logistic orbit The starting position for bit extraction is dynamically determined: The above formula is first calculated To obtain the number of available starting positions, by... Multiply by it and round down to get the preliminary index, then... Modulo operation ensures the index is within a valid range, and finally, addition... Convert to based The index ensures that from Start extracting bits The number of bits will not exceed the 32-bit boundary; Step 5.2, Calculation of extraction length Based on the current state of the Tent orbit The actual extraction length for this iteration is dynamically determined: The above formula uses the basic length Based on, through Will from Mapped to To increase the magnitude of change, multiply by And round down to the nearest integer. Take the modulus to obtain The offset within the range makes the final extraction length exist Changes within the interval; Step 5.3, Multi-track dynamic position extraction operation From three 32-bit fixed-point Dynamic bit extraction is performed in the binary representation, treating each integer as a 32-bit binary string arranged from the most significant bit to the least significant bit, starting from the... Continuous sampling from position 1 The bits are used to obtain three lengths of each. binary string: , , .

7. The frequency hopping sequence design method based on the improved combined jump random shift method according to claim 1, characterized in that, Step 6 involves arranging the binary strings of the main track, Tent track, and Logistic track row-wise to construct a matrix. Then, XOR and modulo operations are performed on the matrix column-wise to obtain two candidate frequency-hopping symbols, as detailed below: Step 6.1: Arrange the binary strings of the main orbital, Tent orbital, and Logistic orbital row by row to construct a... Bit matrix : Step 6.2: XOR and Modulo operations; For matrix Perform an XOR operation column-wise, XORing the three bits of each column to obtain two pairs of lengths. The binary numbers are converted to decimal integers, and then the total number of frequency hopping slots is calculated separately. Taking the modulus, we obtain two candidate frequency hopping symbols: 。 8. The frequency hopping sequence design method based on the improved combined jump random shift method according to claim 1, characterized in that, Step 7 describes the adaptive switching selection of tracks and wide-interval recursive processing to generate the final frequency hopping symbols, as follows: Step 7.1: Adaptively switch to select a track; Based on the current state value of the Logistic orbit In two candidate frequency hopping symbols and Adaptive selection is performed between these sequences, using a sawtooth perturbation selection sequence. Used to control the generation of subsequent sequences. The expression is as follows: Three-combination jump control sequence It is a combined sequence, based on the selected sequence. The value of is used to switch between two different sequences. The expression is as follows: Step 7.2: Main track mold taking preprocessing; Modular operation on the fixed-point values ​​of the main track: Will Mapped to frequency hopping slot range Internally, it serves as the base value for recursive calculations; Step 7.3, Frequency hopping symbol generation operation: When the number of iterations When the first frequency hopping symbol directly takes the modulus value of the main track; when the iteration number... At that time, a wide-interval recursive formula is used to generate frequency hopping symbols.

9. A frequency hopping sequence design system based on an improved combined jump random shift method, characterized in that, This system is used to implement the frequency hopping sequence design method according to any one of claims 1 to 8, the system comprising: The parameter setting and initial value configuration module is used to set and configure the parameters of the frequency hopping communication system. The chaos iteration module is used for chaotic iteration of the main orbit, the Tent orbit, and the Logistic orbit; The mapping control parameter calculation module dynamically calculates the LogSC mapping control parameters based on the current state value of the Tent orbit. The normalization and quantization processing module performs normalization processing and 32-bit fixed-point quantization processing on the main orbit state to obtain the fixed-point values ​​of the main orbit, Tent orbit, and Logistic orbit. The dynamic bit extraction module performs dynamic bit extraction of the fixed-point values ​​of the main track, Tent track, and Logistic track to obtain the binary strings of the main track, Tent track, and Logistic track. The matrix construction module arranges the binary strings of the main track, Tent track, and Logistic track in rows to construct a matrix. It then performs XOR and modulo operations on the matrix column by column to obtain two candidate frequency hopping symbols. The frequency hopping symbol generation module performs adaptive switching selection of tracks and wide-interval recursive processing to generate the final frequency hopping symbol.

10. A computer device, characterized in that, include: The device includes a memory and a processor, which are communicatively connected to each other. The memory stores computer instructions, and the processor executes the computer instructions to perform the frequency hopping sequence design method according to any one of claims 1 to 8.

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