OFDM (Orthogonal Frequency Division Multiplexing) general inductance integrated waveform optimization method, equipment and medium

Abstract

The invention relates to an OFDM (Orthogonal Frequency Division Multiplexing) general inductance integrated waveform optimization method and device and a medium, and the method comprises the steps: carrying out the optimization processing of information bits through employing an optimization algorithm, and generating reserved bits; deploying OFDM subcarriers by adopting a fragmentation and layering mode based on the reserved bits and the information bits, and coding each layer of bit plane to obtain a coded bit sequence; modulating the coded bit sequence of each layer of bit plane through a preset modulation function; and synthesizing the modulated bit sequence to generate an OFDM (Orthogonal Frequency Division Multiplexing) general inductance integrated waveform. According to the method, the peak-to-average ratio (PAPR) and the sidelobe ratio (PSLR) are suppressed, and meanwhile, the radar receiving end can correctly reconstruct the reference signal through a decoding technology.

Description

Technical Field

[0001] This invention relates to the field of OFDM inductive integration technology, and in particular to an OFDM inductive integration waveform optimization method, device and medium. Background Technology

[0002] OFDM (Optical Frequency Division Multiplexing) is an advanced technology that integrates communication and radar functions. By multiplexing communication signals as radar radiation sources (external radiation source radar), it eliminates the need for dedicated radar signals and can significantly improve spectrum efficiency, hardware efficiency, and information processing efficiency. Figure 1 The diagram illustrates a typical OFDM sensing system deployment scenario, consisting of a sensing network comprised of four base stations. Base station 2 transmits communication signals, while base stations 1, 3, and 4 receive these signals and simultaneously receive echo signals from a drone. Each sensing base station has two receiving channels: one for receiving reference signals and the other for monitoring echo signals. Figure 2 It can be seen that the processing flow of the integrated sensing base station is divided into a transmission flow and a reception flow. The reception flow can be further divided into a communication reception processing flow, a reconstruction processing flow, and a radar target detection processing flow.

[0003] OFDM signals are composed of N subcarriers linearly superimposed, and their amplitudes follow a Gaussian distribution. The peak-to-average power ratio (PAPR) is typically 10 dB, easily exceeding the input amplitude range of the analog-to-digital converter (ADC). This causes nonlinear distortion due to ADC clipping, impairing the quality of the echo signal. The peak-to-sidelobe ratio (PSLR) is the ratio of the main lobe peak value to the maximum sidelobe peak value (PSLR has a significant impact on range in low-speed scenarios). An excessively high PSLR can lead to problems such as missed detection of weak targets, generation of false targets in multi-target scenarios, and decreased anti-jamming capabilities, severely affecting radar detection performance.

[0004] Traditional PAPR and PSLR optimization algorithms do not consider the impact of error correction codes in communication. Error correction codes play a crucial role in communication systems, especially in the presence of interference and deep frequency domain fading, enabling the recovery of corrupted subcarrier signals. In radar detection within a sensor-integrated system, it is necessary to reconstruct the transmitted and echo signals for pulse compression processing. If some subcarriers of the transmitted signal are corrupted, the transmitted signal may not be fully recovered, severely impacting radar detection performance. Existing technology (Shakeel I, Grant A. Joint Error Correction and PAPR Reduction of OFDM Signals[C]. IEEE Information Theory Workshop. IEEE,007.DOI:10.1109 / ITW.2006.322891) proposes an improved algorithm based on error correction codes. However, the method proposed in this paper is limited to PAPR and its improvement is limited by the number of error correction codes. More importantly, this method cannot be used in sensor-integrated systems because the receiver recovers the complete error correction code before modification, which is inconsistent with the signal transmitted by the transmitter. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an OFDM integrated waveform optimization method, device and medium that, while suppressing peak-to-average power ratio (PAPR) and sidelobe ratio (PSLR), ensures that the radar receiver can correctly reconstruct the reference signal through decoding technology.

[0006] The technical solution adopted by this invention to solve its technical problem is: to provide an OFDM integrated inductive waveform optimization method, comprising: An optimization algorithm is used to optimize the information bits and generate reserved bits; wherein, the optimization objective of the optimization algorithm is to achieve the best performance in terms of peak-to-average power ratio and peak-to-sidelobe ratio; OFDM subcarriers are deployed using a segmented and layered approach based on reserved bits and information bits, and each bit plane is encoded to obtain the encoded bit sequence. The bit sequence encoded by each bit plane is modulated using a preset modulation function; The modulated bit sequence is synthesized to generate an OFDM integrated sensing waveform.

[0007] When optimizing the information bits using an optimization algorithm, the NSGA-II multi-objective genetic algorithm is used.

[0008] When optimizing information bits using the NSGA-II multi-objective genetic algorithm, a preset length of binary bits is used as the chromosome individuals in the population, specifically including: Within the feasible region, P chromosome individuals are randomly generated to obtain the initial offspring population; For each chromosome individual in the current offspring population, encoding, modulation, and IFFT operations are performed separately, and the peak-to-average ratio and peak-to-sidelobe ratio are calculated. The population selected by the parent environment and the current offspring population are merged to obtain a joint population. The current offspring population is divided into multiple frontier layers with priority based on the peak-to-average ratio and peak-to-sidelobe ratio of each chromosome individual, and the crowding distance of each chromosome individual in the frontier layer is calculated. The frontier layer is filled into the population after the parent environment selection in priority order until the preset size P is reached; The minimum value of the objective function is calculated based on the highest priority front layer, and it is then determined whether the convergence threshold has been reached. If the convergence threshold is not reached and the maximum number of generations is not reached, then the chromosome individuals in the population selected by the parent environment will undergo crossover and mutation operations to generate a new offspring population, and the encoding, modulation and IFFT operations will be performed on each chromosome individual in the current offspring population respectively. If the convergence threshold or the maximum number of generations is reached, the chromosome individuals in the population selected by the parent environment will be reserved bits.

[0009] The current offspring population is divided into multiple frontier layers with priority based on the peak-to-average ratio and peak-to-sidelobe ratio corresponding to each chromosome individual, specifically as follows: If candidate chromosome individuals It was non-inferior to candidate chromosome individuals in both peak-to-average ratio and peak-to-sidelobe ratio. Furthermore, at least one of the peak-to-average ratio and peak-to-sidelobe ratio is significantly better than that of the candidate chromosome individual. Then candidate chromosome individuals Dominant candidate chromosome individuals Based on the dominance relationships of candidate chromosome individuals, the current offspring population is divided into multiple frontier layers with different existence priorities.

[0010] The method for calculating the congestion distance is as follows: ,in, Individuals with chromosomes Crowded distance, For individuals with chromosomes In the The previous target value on each target, For individuals with chromosomes In the The next target value on each target, and They were respectively in the second The target values ​​of the best and worst chromosome individuals on each objective, when... The value of peak-to-average ratio (PAR) is represented by the target value when... The value indicated is the target value for the peak sidelobe ratio.

[0011] The process involves filling the frontal layer into the population selected by the parent environment in priority order until a preset size P is reached. If the number of chromosome individuals in the last-level frontal layer exceeds the remaining quota, the chromosomes in the last-level frontal layer are truncated from largest to smallest based on the crowding distance.

[0012] When deploying OFDM subcarriers using a segmented and layered approach based on reserved bits and information bits, segmentation refers to dividing the OFDM subcarriers into reserved subcarriers, information subcarriers, parity subcarriers, and unused subcarriers; layering refers to dividing the information bits into multiple bit planes according to the number of information bits corresponding to the OFDM subcarriers; wherein, the reserved subcarriers are used to carry the reserved bits; the information subcarriers are used to carry the information bits; the parity subcarriers are used to carry the coded parity bits; and the unused subcarriers are used for redundancy.

[0013] The encoding of each bit plane layer is performed using BCH codes.

[0014] The technical solution adopted by the present invention to solve its technical problem is: to provide an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the above-mentioned OFDM inductive waveform optimization method.

[0015] The technical solution adopted by the present invention to solve its technical problem is: to provide a computer-readable storage medium on which a computer program is stored, wherein the computer program, when executed by a processor, implements the steps of the above-mentioned OFDM integrated waveform optimization method.

[0016] Beneficial effects Due to the adoption of the above technical solution, the present invention has the following advantages and positive effects compared with the prior art: The present invention considers the waveform optimization and error correction coding constraints of PAPR and PSLR in a unified manner, which can ensure that the reference signal errors caused by deep fading or interference are correctly recovered while optimizing PAPR and PSLR, thus significantly improving the detection performance of the OFDM integrated sensing system. Attached Figure Description

[0017] Figure 1This is a schematic diagram of an OFDM integrated sensing system deployment scenario in existing technology; Figure 2 This is a flowchart of the signal processing of an integrated sensing base station in the existing technology; Figure 3 This is a flowchart of the signal processing of the integrated sensing base station in the first embodiment of the present invention; Figure 4 This is a flowchart of the OFDM integrated waveform optimization method according to the first embodiment of the present invention; Figure 5 This is a schematic diagram of a 4-bit plane in the first embodiment of the present invention; Figure 6 This is a flowchart of the genetic algorithm generating reserved bits in the first embodiment of the present invention. Detailed Implementation

[0018] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0019] The first embodiment of the present invention relates to an OFDM integrated waveform optimization method, which optimizes information bits before encoding to achieve optimal PAPR and PSLR performance. Figure 3 and Figure 1 A comparison reveals that this implementation adds an optimization step for information bits, which generates reserved bits to improve the PAPR and PSLR performance of the integrated inductive transmit waveform.

[0020] like Figure 4 As shown, the OFDM integrated inductive waveform optimization method of this embodiment specifically includes the following steps: Step 1: Optimize the information bits using an optimization algorithm to generate reserved bits; wherein the optimization objective of the algorithm is to achieve the best performance in terms of peak-to-average power ratio (PAPR) and peak-to-sidelobe ratio (PSS). Figure 6 As shown, this step uses the NSGA-II multi-objective genetic algorithm to optimize the information bits. Taking the QAM modulation scenario as an example, this implementation uses a length of... The binary bits are used as chromosomes for individual individuals in the population, where, To reserve the length of subcarriers, The number of modulation bits for each subcarrier specifically includes the following steps: Generate the initial offspring population: Randomly generate P chromosome individuals within the feasible region to obtain the initial offspring population.

[0021] Population evaluation steps: For each chromosome individual in the current offspring population, encode, modulate, and perform IFFT operations, and calculate PAPR and PSLR. Then, merge the parent-selected population and the current offspring population to obtain a joint population.

[0022] Generating PARETO dominance relationships: In the evolutionary process, the evaluation of the quality of chromosome individuals depends on multi-objective optimized Pareto dominance relationships and crowding distance. This step divides the current offspring population into multiple frontier layers with existence priority based on the peak-to-average ratio and peak-to-sidelobe ratio corresponding to each chromosome individual. Specifically, if candidate chromosome individuals... It was non-inferior to candidate chromosome individuals in both peak-to-average ratio and peak-to-sidelobe ratio. Furthermore, at least one of the peak-to-average ratio and peak-to-sidelobe ratio is significantly better than that of the candidate chromosome individual. Then candidate chromosome individuals Dominant candidate chromosome individuals Based on the dominance relationships of candidate chromosome individuals, the current offspring population is divided into multiple frontier layers with different existence priorities. Among them, the frontier layer The chromosome individuals in the text represent all non-dominated individuals, the frontal layer. The chromosomes in the image are those with the leading edge layer removed. All subsequent undominated individuals follow the same pattern. Each chromosome individual thus acquires a hierarchical rank to reflect its position in the Pareto hierarchy.

[0023] Within the same leading edge layer, it is necessary to further calculate the crowding distance of individual chromosomes to measure their sparsity in the target space. Specifically, for the leading edge layer... The chromosome individuals in the dataset are normalized and sorted in each target dimension. Let the chromosome individuals be... In the The target values ​​for adjacent chromosome individuals on each target are respectively and Then the individual chromosome Crowded distance is defined as: .in, and They were respectively in the second The target values ​​of the best and worst chromosome individuals on each objective, when... The time represents the target value of PAPR. The value represents the target value of PSLR. For boundary individuals, it can be directly set to... This is to ensure that the diversity of solution set boundaries is preserved.

[0024] Generate the parent-environment-selected population: After completing the non-dominated sorting and crowding distance calculation, the frontier layer is filled into the parent-environment-selected population according to priority until a preset size P is reached. If the number of chromosome individuals in the last-level frontier layer exceeds the remaining quota, the population is truncated from largest to smallest based on the crowding distance of the chromosome individuals in the last-level frontier layer. This mechanism ensures that the dominance of the Pareto optimal solution is maintained during the selection process, while also maintaining the population distribution balance within the target space, thus effectively balancing convergence and diversity.

[0025] Termination condition determination: based on the highest priority frontier layer (i.e., the frontier layer) Calculate the minimum value of the objective function, which can be expressed as: , The preset weights are used. The minimum value of the objective function determines whether the convergence threshold has been reached. If the convergence threshold or the maximum number of generations is reached, the chromosomes of the population selected by the parent environment are reserved bits.

[0026] If the convergence threshold and the maximum number of generations are not reached, crossover and mutation operations are performed on the chromosomes of the population selected by the parent environment to generate a new offspring population, and the process returns to the population evaluation step. When generating a new offspring population, the crossover operation is performed first, which can be represented as: ,in, and These are the offspring chromosomes obtained after the crossover operation. and These are individual chromosomes from a population that has undergone environmental selection in the parent generation. ,here It means OK The algorithm generates a random 0-1 matrix. Then, a mutation operation is applied to the offspring individuals; specifically, some bits are randomly flipped in the generated individuals. To avoid excessive mutation causing deviations in the search direction, the number of flips can be set to not exceed a predetermined value. This design ensures both random perturbation of individuals to maintain population diversity and prevents non-convergence caused by drastic changes, thus obtaining the offspring population from the population selected by the parent environment.

[0027] Step 2: Based on the reserved bits and information bits, OFDM subcarriers are deployed in a segmented and layered manner, and each bit plane is encoded to obtain the encoded bit sequence.

[0028] In this step, fragmentation refers to dividing the OFDM subcarriers into reserved subcarriers, information subcarriers, parity subcarriers, and unused subcarriers. The reserved subcarriers carry the reserved bits; the information subcarriers carry the information bits; the parity subcarriers carry the encoded parity bits; and the unused subcarriers are reserved for redundancy. Layering refers to dividing the information bits into multiple bit planes according to the number of information bits corresponding to each OFDM subcarrier.

[0029] In this embodiment, BCH codes can be used for encoding each bit plane. This encoding method divides all bits into K bit planes and encodes them separately, based on the number of bits in each subcarrier. Figure 5 This is an example of a subcarrier deployment with 64 subcarriers using QAM16 modulation. As shown in the figure, this OFDM waveform has a total of 64 subcarriers, of which the first 12 are reserved subcarriers, the middle 39 are information subcarriers, one is unused subcarrier, and the last 12 are parity subcarriers. The figure also shows that QAM16 corresponds to 4 bit coding planes. The first bit of the reserved subcarrier, the first bit of the information subcarrier, and the first bit of the parity subcarrier form the first bit coding plane. In this bit plane, the 12 reserved bits and the 39 information bits are encoded to generate 12 parity bits; and so on.

[0030] The parity bits of a BCH code can be viewed as the modulo-2 sum of the parity vectors corresponding to each coded bit. For each bit plane, the encoding formula is: ,in, Indicates the first Information bits in the plane Indicates the first Planar reserved bits Indicates the first Planar parity bits It is an encoding matrix, along with a bit vector. After modulo-2 multiplication, a parity bit matrix is ​​generated. All bit planes can be simplified as follows: ,in, The message bit sequence corresponding to the information subcarrier. To reserve the bit sequence corresponding to the reserved subcarrier, This is the parity bit sequence corresponding to the check subcarrier.

[0031] Step 3: Modulate the bit sequence encoded in each bit plane using a preset modulation function. The preset modulation function in this step can be a QAM modulation function. Step 4: Synthesize the modulated bit sequence to generate an OFDM integrated sensing waveform.

[0032] It is easy to see that this invention considers the waveform optimization and error correction coding constraints of PAPR and PSLR in a unified manner, which can ensure that the reference signal errors caused by deep fading or interference are correctly recovered while optimizing PAPR and PSLR, thus significantly improving the detection performance of the OFDM integrated sensing system.

[0033] The second embodiment of the present invention relates to an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the OFDM inductive waveform optimization method of the first embodiment.

[0034] The third embodiment of the present invention relates to a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the OFDM inductive waveform optimization method of the first embodiment.

[0035] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0036] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0037] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to operate in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction methods implemented in a process. Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0038] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0039] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An OFDM integrated waveform optimization method, characterized by, The method comprises the steps of: Optimizing information bits by using an optimization algorithm to generate reserved bits, wherein the optimization target of the optimization algorithm is to make the performance of peak-to-average ratio and peak side lobe ratio optimal; Deploying OFDM subcarriers in a slicing and layering manner based on the reserved bits and the information bits, and encoding each layer of bit planes to obtain encoded bit sequences; Modulating the encoded bit sequences of each layer of bit planes by using a preset modulation function; Synthesizing the modulated bit sequences to generate an OFDM waveform.

2. The OFDM waveform optimization method according to claim 1, wherein When the information bits are optimized by using the optimization algorithm, the information bits are optimized by using an NSGA-II multi-objective genetic algorithm.

3. The OFDM waveform optimization method of claim 1, wherein When the information bits are optimized by using the NSGA-II multi-objective genetic algorithm, a preset length of binary bits is used as chromosome individuals in a population, and the method comprises the steps of: Randomly generating P chromosome individuals in a feasible region to obtain an initial offspring population; Encoding, modulating and performing IFFT operation on each chromosome individual in the current offspring population, and calculating the peak-to-average ratio and the peak side lobe ratio, combining the population selected by the parent environment and the current offspring population to obtain a joint population; Dividing the current offspring population into multiple priority front layers according to the peak-to-average ratio and the peak side lobe ratio corresponding to each chromosome individual, and calculating the crowding distance of each chromosome individual in the front layer; Filling the front layers into the population selected by the parent environment in priority order until the preset size P is reached; Calculating the minimum value of the objective function according to the front layer with the highest priority, and judging whether the convergence threshold is reached; If the convergence threshold is not reached and the maximum number of generations is not reached, performing crossover and mutation operations on the chromosome individuals in the population selected by the parent environment to generate a new offspring population, and returning to the step of encoding, modulating and performing IFFT operation on each chromosome individual in the current offspring population; If the convergence threshold is reached or the maximum number of generations is reached, the chromosome individuals in the population selected by the parent environment are used as reserved bits.

4. The OFDM waveform optimization method according to claim 3, wherein The current offspring population is divided into multiple priority front layers according to the peak-to-average ratio and the peak side lobe ratio corresponding to each chromosome individual. If the candidate chromosome individual is not worse than the candidate chromosome individual in both the peak-to-mean ratio and the peak-to-side lobe ratio and is better than the candidate chromosome individual in at least one of the peak-to-mean ratio and the peak-to-side lobe ratio , the candidate chromosome individual dominates the candidate chromosome individual , the current offspring population is divided into multiple priority existing front layers according to the dominance relationship of the candidate chromosome individual.

5. The OFDM waveform optimization method of claim 3, wherein, The method for calculating the congestion distance is as follows: ,in, Individuals with chromosomes Crowded distance, For individuals with chromosomes In the The previous target value on each target, For individuals with chromosomes In the The target value of the next target, and They were respectively in the second The target values ​​of the best and worst chromosome individuals on each objective, when... The value of peak-to-average ratio (PAR) is represented by the target value. The value indicated is the target value for the peak sidelobe ratio.

6. The OFDM waveform optimization method of claim 3, wherein, When the front layers are filled into the population selected by the parent environment in priority order until the preset size P is reached, if the number of chromosome individuals in the last front layer exceeds the remaining number of places, the chromosome individuals in the last front layer are truncated from large to small according to their crowding distances.

7. The OFDM waveform optimization method of claim 1, wherein When the OFDM subcarriers are deployed in a slicing and layering manner based on the reserved bits and the information bits, the slicing refers to dividing the OFDM subcarriers into reserved subcarriers, information subcarriers, check subcarriers and unused subcarriers; the layering refers to dividing the information bits into multiple layers of bit planes according to the number of information bits corresponding to the OFDM subcarriers; wherein the reserved subcarriers are used to carry the reserved bits; the information subcarriers are used to carry the information bits; the check subcarriers are used to carry the encoded check bits; and the unused subcarriers are used for redundancy reservation.

8. The OFDM omnistatic integrated waveform optimization method of claim 1, wherein, The BCH code is used for encoding each layer of bit plane.

9. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, The computer program is executed by the processor to realize the steps of the OFDM all-sensing integrated waveform optimization method in any one of claims 1-8.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The computer program is executed by the processor to realize the steps of the OFDM all-sensing integrated waveform optimization method in any one of claims 1-8.

Images