A system and method for optimizing logic circuit complexity of spread spectrum communication system

Abstract

The present invention discloses a system and method for optimizing the logic circuit complexity of a spread-spectrum communication system. The system includes a data buffer module (RxBuffer), a local spread-spectrum sequence generation module (LocalCSSGen), an FFT-based time-domain circular correlation despreading module (RxDeCSS), and a despreading parameter control module (RxCtrlModul). The system utilizes a joint mechanism technology that combines local coarse correlation despreading of a low-sampling-rate complete symbol period sequence with fine correlation despreading of a high-sampling-rate truncated symbol period sequence for despreading spread-spectrum symbols. By dynamically setting the compression ratio of the buffer module and the local spread-spectrum sequence, accessing the initial index, and truncating the spread-spectrum sequence length, the system performance requirement for the FFT length is reduced, thereby reducing the complexity and difficulty of implementing the FFT logic circuit of the spread-spectrum communication chip, achieving chip area optimization, and promoting optimization of the overall area of ​​the spread-spectrum communication chip while ensuring high sensitivity and large capacity system requirements.

Description

Technical Field

[0001] The present invention relates to spread spectrum communication, and in particular to a system and method for optimizing the complexity of logic circuits in a spread spectrum communication system. Background Art

[0002] In the IoT era, tens of billions of objects will be connected to the network. Traditional access technologies include short-range wireless access and mobile cellular networks, each with its own advantages and disadvantages. Short-range wireless access technologies like WiFi, Bluetooth, and ZigBee offer advantages such as high stability and fast access speeds within a specific spatial range. However, their coverage is limited, and they rely heavily on backhaul networks. Furthermore, due to insufficient interference mitigation and design considerations, terminals consume high power, hindering long-term use. While mobile cellular networks can meet the needs of large-scale or mobile applications, their primary challenge is limited system capacity. Access for IoT applications cannot be completely isolated from that for public users, resulting in a mutual capacity constraint. This makes it difficult for them to independently cope with the rapid growth of the IoT market. Furthermore, they rely on the mobile core network for terminal node management, resulting in a significant consumption of number resources. Furthermore, IoT terminals based on 2G, 3G, and 4G networks still face challenges with high module costs and short battery life.

[0003] In reality, communication between things doesn't necessarily require high bandwidth like human-to-human communication. A large number of devices connected to the network require only small amounts of data transmission, or data transmission is very infrequent. Unlike human-to-human communication, which requires frequent recharging, many devices, due to their unique environments and sheer number, require relatively low power consumption to support their communication. For example, for water meter monitoring, smoke alarms, farm irrigation, and hydrological monitoring, the most effective solution for networking these sensor devices is a low-bandwidth, low-power network with wide coverage. In this sense, the development of the "Internet of Everything" IoT industry has spurred the rise of LPWA (Low Power Wide Area) technology. LPWA's four key capabilities are low power consumption, low cost, wide coverage, and high capacity. Reducing costs has become a key technical challenge. As we all know, chip cost is directly related to chip area.

[0004] It should be noted that the information disclosed in the above background technology section is only used to understand the background of this application, and therefore may include information that does not constitute prior art known to ordinary technicians in this field. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a system and method for optimizing the complexity of the logic circuit of the spread spectrum communication system, thereby reducing the complexity and difficulty of implementing the FFT logic circuit of the spread spectrum communication chip while meeting the application requirements of high sensitivity and large capacity, realizing chip area optimization, and thus promoting the optimization of the overall chip area.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A system for optimizing the logic circuit complexity of a spread spectrum communication system includes a data buffer module RxBuffer, a local spread spectrum sequence generation module LocalCSSGen, an FFT-based time domain circular correlation despreading module RxDeCSS, and a despreading parameter control module RxCtrlModul;

[0008] The despreading parameter control module RxCtrlModul configures a compression ratio that satisfies the storage of a complete symbol period sequence and a starting index for initializing the spreading sequence when the current spreading sequence starts the first despreading, and starts the first despreading process; after the first despreading process, based on system requirements, determines whether to start the second despreading process; if necessary, adjusts the local sequence generation offset address, compression ratio, and spreading sequence truncation length based on the despreading information; sets the compression ratio of the cache module, the cache starting address, and the received data truncation length, and starts the second despreading process;

[0009] The data buffer RxBuffer provides the time domain circular correlation despreading module with a compressed spread spectrum sequence of a complete symbol period at a low sampling rate and a truncated spread spectrum sequence of an incomplete symbol period at a high sampling rate based on effective storage of different compression ratios, starting storage locations, and storage lengths;

[0010] The local spreading sequence generation module LocalCSSGen provides the time domain circular correlation despreading module with a compressed local spreading sequence of a complete symbol period and a truncated local spreading sequence of an incomplete symbol period based on different compression ratios and spreading sequence offset addresses;

[0011] The time-domain circular cyclic correlation despreading module RxDeCSS implements a secondary time-domain circular correlation despreading mechanism that combines local coherent despreading of compressed received spread spectrum sequences for complete symbol periods (referred to as complete-period coarse despreading) with local coherent despreading of high-sampling-rate received spread spectrum sequences for incomplete symbol periods (referred to as truncated-period fine despreading), and outputs the final despread symbol information.

[0012] Furthermore, during the first despreading, a compression ratio that satisfies the storage of a complete symbol period sequence is configured. It is based on the system's buffer space BufferLen, the maximum FFT length FFTLen supported by the FFT module, and different spreading sequence length N configurations to meet the following requirements:

[0013]

[0014] Furthermore, the compression ratio and sequence truncation length of the data buffer RxBuffer module and the local spread spectrum sequence generation module LocalCSSGen are consistent, and the second compression ratio is not greater than the first compression ratio, that is, Ensure high resolution of the second processing.

[0015] Further, Ensure the highest chip resolution.

[0016] Furthermore, the despreading parameter control module RxCtrlModul is based on the first despreading correlation peak position PeakIdx 1 , and compression ratio Considering the impact of the deviation introduced by the initial low-sampling-rate coarse despreading error, adjust the local sequence generation offset address LocalShift. The calculation formula is as follows:

[0017]

[0018] Wherein m is a calculated correction parameter, preferably, m is 2-10.

[0019] Furthermore, in the truncation cycle fine despreading state, the truncation length Ntruc of the data buffer module RxBuffer and the local spread spectrum generation module LocalCSSGen satisfies: truncation length

[0020] Furthermore, the combined secondary time-domain circular correlation despreading mechanism outputs the final despread symbol information, and the calculation formula is as follows:

[0021] / Shift interval between adjacent spread spectrum symbols, where LocalShift represents the offset address, Indicates the second compression ratio, PeakIdx 2 Indicates the correlation peak position of the secondary despreading, and SymValue indicates the symbol value obtained by despreading.

[0022] Since the truncated period fine despreading uses a high sampling rate spread spectrum sequence, the time domain correlation peak PeakIdx 2 It has high resolution, thus ensuring the despreading accuracy of SymValue.

[0023] Furthermore, the time domain circular cyclic correlation despreading module RxDeCSS performs the first despreading process, uses FFT to implement circular cyclic correlation, and completes the correlation peak Peak 1 and peak position PeakIdx 1 The search is based on the following formula:

[0024] [Peak 1 ,PeakIdx 1 ]=max(abs(ifft(fft(RxData).*conj(LocalCSS))).^2)

[0025] The time domain circular cyclic correlation despreading module RxDeCSS performs secondary despreading processing, uses FFT to implement circular cyclic correlation, and completes the correlation peak Peak 2 and peak position PeakIdx 2 The search is based on the following formula:

[0026] [Peak 2 ,PeakIdx 2 ]=max(abs(ifft(fft(RxData_trunc).*conj(LocalCSS_trunc))).^2)

[0027] Among them, abs is the modulo processing; fft is the Fourier transform; ifft is the inverse Fourier transform; RxData_truc is the received data for the second despreading, and LocalCSS_trunc is the truncated sequence generated by LocalCSSGen for the second despreading, which is a partial truncation of the complete local despreading sequence.

[0028] A method for optimizing the complexity of logic circuits in a spread spectrum communication system, using the system, the method comprising:

[0029] When the first despreading of the current spreading sequence is started, the despreading parameter control module RxCtrlModul configures the compression ratio that satisfies the storage of the complete symbol period sequence and the starting index of the initial spreading sequence, and starts the first despreading process. After the first despreading process, based on system requirements, it determines whether to start the second despreading process. If necessary, it adjusts the local sequence generation offset address, compression ratio, and spread spectrum sequence truncation length based on the despreading information. It also sets the compression ratio of the cache module, the cache starting address, and the received data truncation length, and starts the second despreading process.

[0030] The data buffer RxBuffer provides the time domain circular correlation despreading module with a compressed spread spectrum sequence of a complete symbol period at a low sampling rate and a truncated spread spectrum sequence of an incomplete symbol period at a high sampling rate based on the effective storage of different compression ratios, starting storage locations, and storage lengths.

[0031] The local spreading sequence generation module LocalCSSGen provides the time domain circular correlation despreading module with compressed local spreading sequences of complete symbol periods and truncated local spreading sequences of incomplete symbol periods based on different compression ratios and spreading sequence offset addresses;

[0032] The time-domain circular correlation despreading module RxDeCSS implements a secondary time-domain circular correlation despreading mechanism that combines local coherent despreading of the compressed received spread spectrum sequence for a complete symbol period with local coherent despreading of the high sampling rate received spread spectrum sequence for an incomplete symbol period, and outputs the final despread symbol information.

[0033] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the method for optimizing the complexity of a spread spectrum communication system logic circuit.

[0034] As described above, in some embodiments, the present invention proposes a joint mechanism for optimizing the logic circuit complexity of a spread spectrum communication system. This joint mechanism primarily involves four functional modules: a data buffer module (RxBuffer); a local spreading sequence generation module (LocalCSSGen); an FFT-based time-domain circular correlation despreading module (RxDeCSS); and a secondary circular correlation despreading feedback mechanism (RxCtrlModul) within the despreading parameter control module (RxCtrlModul). When initial despreading of the current spreading sequence is initiated, the despreading parameter control module (RxCtrlModul) configures the minimum compression ratio required to store a complete symbol period sequence and the initial starting index for the spreading sequence, and initiates the initial despreading process. After the initial despreading process, the module determines whether to initiate secondary despreading based on system requirements. If necessary, it adjusts the local sequence generation offset address, compression ratio, and spreading sequence truncation length based on the despreading information; the buffer module's compression ratio, buffer starting address, and received data truncation length; and initiates secondary despreading. The data buffer RxBuffer, based on effective storage of different compression ratios, starting storage locations, and storage lengths, flexibly provides the despreading module with compressed spread spectrum sequences for complete symbol periods at low sampling rates and truncated spread spectrum sequences for incomplete symbol periods at high sampling rates. The local spread spectrum sequence generation module LocalCSSGen, based on different compression ratios and spread spectrum sequence offset addresses, flexibly provides the despreading module with compressed local spread spectrum sequences for complete symbol periods and truncated local spread spectrum sequences for incomplete symbol periods. The time domain circular cyclic correlation despreading module RxDeCSS implements a secondary time domain circular correlation despreading mechanism that combines local coherent despreading of compressed received spread spectrum sequences for complete symbol periods (referred to as complete cycle coarse despreading) with local coherent despreading of high sampling rate received spread spectrum sequences for incomplete symbol periods (referred to as truncated cycle fine despreading), and outputs the final despread symbol information.

[0035] The present invention has the following beneficial effects:

[0036] The present invention provides a system and method for optimizing the logic circuit complexity of a spread-spectrum communication system. This system proposes a joint mechanism technology that employs a feedback mechanism combining coarse local correlation despreading of a low-sampling-rate complete symbol period sequence with fine correlation despreading of a high-sampling-rate truncated symbol period sequence for spread-spectrum symbol despreading. By dynamically setting the compression ratio of a cache module and the local spreading sequence, accessing the initial index, and truncating the spreading sequence length, the system's performance requirements for the FFT length are reduced, thereby reducing the complexity and difficulty of implementing the FFT logic circuitry in the spread-spectrum communication chip. This reduces chip area, promoting overall chip area optimization while ensuring high sensitivity and large capacity system requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1This is a flow chart of a joint mechanism for a method of optimizing logic circuit complexity of a spread spectrum communication system according to an embodiment of the present invention.

[0038] Figure 2 This section describes the compression ratio and other parameter settings of the combined mechanism according to an embodiment of the present invention.

[0039] Figure 3 Schematic diagram of time-domain circular cyclic correlation processing according to an embodiment of the present invention. DETAILED DESCRIPTION

[0040] The following is a detailed description of the embodiments of the present invention. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present invention and its application.

[0041] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element. In addition, connection can be used for both fixing and coupling or communication.

[0042] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limiting the present invention.

[0043] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0044] See Figures 1 to 3 The embodiments of the present invention provide a system and method for optimizing the logic circuit complexity of a spread spectrum communication system, and propose a joint mechanism technology. This joint mechanism uses quadratic circular cyclic correlation to realize the despreading of spread spectrum symbols, which involves four major functional modules: a data buffer module RxBuffer, a local spread spectrum sequence generation module LocalCSSGen, an FFT-based time-domain circular correlation despreading module RxDecss, and a despreading parameter control module RxCtrModul.

[0045] The despreading control module configures the compression ratio that satisfies the storage of the complete symbol period sequence when the current spread spectrum sequence starts the first despreading. It is based on the system's buffer space BufferLen, the maximum FFT length FFTLen supported by the FFT module, and different spreading sequence length N configurations to meet the following requirements: The first despreading process is initiated. After the first despreading process, based on system requirements, a decision is made as to whether to initiate a second despreading process. If necessary, the system adjusts the local sequence generation offset address, compression ratio, and spread spectrum sequence truncation length based on the despreading information; the cache module compression ratio, cache start address, and received data truncation length; and initiates the second despreading process.

[0046] In the compression ratio setting, the second compression ratio is not greater than the first compression ratio, that is, Ensure high resolution of the second processing. To ensure the highest chip resolution. When adjusting the local sequence generation offset address LocalShift, the control module is based on the first despreading related peak position PeakIdx 1 , considering the deviation introduced by the first low sampling rate coarse despreading error, set: In the truncation cycle fine despreading state, the truncation length Ntruc of the data buffer module RxBuffer and the local spread spectrum generation module LocalCSSGen meets the truncation length The combined secondary time domain circular correlation despreading mechanism outputs the final despread symbol information. The calculation formula is:

[0047] / Shift interval between adjacent spread spectrum symbols;

[0048] Since the truncated period fine despreading uses a high sampling rate spread spectrum sequence, the time domain correlation peak PeakIdx 2 With high resolution, the despreading accuracy of SymValue is guaranteed; therefore, the compression ratio of the joint mechanism is The truncation length Ntruc has the feature of being flexibly set based on the length of FFTLen. In other words, the joint mechanism can be adjusted reasonably Configuration value, reduce the system performance requirements for FFT length, thereby achieving area optimization of the FFT function module of the spread spectrum communication chip, while ensuring the system requirements of high sensitivity and large capacity, promoting the optimization of the overall area of ​​the spread spectrum communication chip.

[0049] In a specific embodiment, the basic parameters of the system are first set, bandwidth BW = 125kHz, linear spread spectrum Chirp is used, support spreading factor SF = 5 to 10, symbol period Tc = 2 SF / BW, the system sampling rate fs = 500kHz. Therefore, at the receiving end, the system needs to process symbol sequences of lengths from 128 to 4096. Therefore, when not using a compression solution, the system needs to support a maximum FFT length of 4096. This solution can reduce the number of FFT points based on the chip area requirements. Here, it is assumed that the maximum FFT length MaxFFTLen = 1024; the buffer length is MaxFFTLen + 26 (based on the need for advanced symbol correction) = 1100.

[0050] Figure 2 The table shows the joint mechanism of an embodiment of the present invention, which mainly includes the following parameters for different SF modes based on the settings of maxFFTLen and Buffer:

[0051] (a) Specific settings of the Buffer write ratio InRatio and the access segment ratio SegRatio;

[0052] (b) a local spreading sequence generation module LocalCSSGen, which generates a generation ratio FFTRatio and a segmentation ratio SegRatio of the local spreading sequence;

[0053] (c) The table shows that SF5 uses the single despreading mode and SF10 uses the double despreading mode;

[0054] (d) Clarify the buffer and LocalCSSGen ratio settings for the two despreading designs of SF10, where 10-1 is the configuration related to the first despreading and the first data cache compression ratio. 10-2 is the second related configuration, the second data cache compression ratio

[0055] (e) When SF10 performs secondary despreading, a truncated sequence with a low compression ratio is used, and the truncated sequence ratio is SegRatio;

[0056] from Figure 2 As can be seen from the table, the InRatio and SegRatio of buffer and LocalCSSGen are consistent. In a specific embodiment, the generation of LocalCSSGen is set based on LocalShift. The following will be combined with the specific parameters in the above table, taking SF10 as an example for specific explanation;

[0057] Step 1: At the beginning of the first despreading process, the control module RxCtrlModul performs the corresponding settings of the above related parameters: SegRation=1, FFTLen=1024;

[0058] Step 2, SF10 mode, the first despreading adopts the local coherent despreading of the compressed received spread spectrum sequence of the complete code element period, referred to as the complete cycle coarse despreading. Its compression ratio The processing is to divide the entire code element period sequence Rx of length 2^(10+2)=4096 into segments, average each 4 segments, and the new sequence length is RxData, which is 1024. The first LocalCSSGen also uses the same method to perform compression processing to obtain the local spread spectrum sequence LocalCSS.

[0059] Step 3: The time domain circular correlation despreading module RxDeCSS performs the first despreading process, uses FFT to implement circular correlation, and completes the correlation peak Peak. 1 and peak position PeakIdx 1 The search is based on the following formula:

[0060] [Peak 1 ,PeakIdx 1 ]=max(abs(ifft(fft(RxData).*conj(LocalCSS))).^2)

[0061] Step 4: The control module is based on the first despreading correlation peak position PeakIdx 1 , adjust the local sequence to generate the offset address:

[0062]

[0063] When adjusting the locally generated offset address LocalShift, the influence of the deviation introduced by the initial low sampling rate coarse despreading error is considered. m is a correction parameter introduced into the LocalShift calculation to consider the influence of the deviation introduced by the initial low sampling rate coarse despreading error. It is set according to specific statistical analysis results and is preferably set to between 2 and 10. Here, m=2;

[0064] Step 5: Start secondary despreading, and set the corresponding parameters of the above parameters in the control module RxCtrlModul: SegRation=0.25, FFTLen=1024, truncated sequence length It should be noted that although the parameter SegRatio for both Buffer and LocalCSSGen is 0.25, their specific processing is different. In the Buffer processing, data with symbol indices 1 to Ntruc are selected as the received data RxData_truc for the second despreading. LocalCSSGen generates a truncated sequence for the second despreading, which is a partial truncation of the complete local despreading sequence, LocalCSS_trunc, with indices LocalShift+1 to LocalShift+Ntruc.

[0065] Step 6: The time domain circular correlation despreading module RxDeCSS performs secondary despreading processing, uses FFT to implement circular correlation, and completes the correlation peak Peak 2 and peak position PeakIdx 2 The search is based on the following formula:

[0066] [Peak 2 ,PeakIdx 2 ]=max(abs(ifft(fft(RxData_trunc).*conj(LocalCSS_trunc))).^2)

[0067] Among them, abs is the modulo processing; fft is the Fourier transform; ifft is the inverse Fourier transform; RxData_truc is the received data for the second despreading, and LocalCSS_trunc is the truncated sequence generated by LocalCSSGen for the second despreading, which is a partial truncation of the complete local despreading sequence.

[0068] Step 7: Combined with the secondary time-domain circular correlation despreading mechanism, the final despread symbol information is output. The calculation formula for the output despread symbol information is as follows:

[0069]

[0070] Since the truncated period fine despreading uses a low compression ratio and high sampling rate spread spectrum sequence, the time domain correlation peak PeakIdx 2 It has high symbol resolution, thus ensuring the despreading accuracy of SymValue. Figure 2 This mechanism combines hardware memory space with flexible configuration of compression ratios for parameter settings under various SFs. Low SF uses one high-codeword precision despreading, while high SF uses two despreadings. A joint compression mechanism is used to adjust the maximum FFT length required to be supported by the system from 4096 to 1024, achieving a 4-fold reduction. This reduces the complexity and difficulty of implementing the FFT logic circuit of the spread spectrum communication chip, and optimizes the chip area.

[0071] The background section of the present invention may contain background information about the problem or environment of the present invention, but does not necessarily describe the prior art. Therefore, the inclusion of content in the background section is not an admission by the applicant that the prior art is present.

[0072] The above description further details the present invention in conjunction with specific / preferred embodiments, and the specific implementation of the present invention should not be construed as being limited to these descriptions. Persons skilled in the art will appreciate that, without departing from the spirit of the present invention, they may make various substitutions or modifications to the described embodiments, and these substitutions or modifications should be considered to fall within the scope of protection of the present invention. Throughout this specification, reference to terms such as "one embodiment," "some embodiments," "preferred embodiments," "examples," "specific examples," or "some examples" indicates that the specific features, structures, materials, or characteristics described in conjunction with such embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of these terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples. Persons skilled in the art may combine and assemble the different embodiments or examples described in this specification, as well as features of different embodiments or examples, without conflicting opinions. Although the embodiments of the present invention and their advantages have been described in detail, it should be understood that various changes, substitutions, and modifications may be made herein without departing from the scope of protection of the patent application.

Claims

1. A system for optimizing the logic circuit complexity of a spread spectrum communication system, characterized in that: It includes a data buffer module RxBuffer, a local spread spectrum sequence generation module LocalCSSGen, an FFT-based time domain circular cyclic correlation despreading module RxDeCSS, and a despreading parameter control module RxCtrlModul; The despreading parameter control module RxCtrlModul configures a compression ratio that satisfies the storage of a complete symbol period sequence and a starting index of the initial spread spectrum sequence when the current spread spectrum sequence starts despreading for the first time, and starts the first despreading process; After the initial despreading process, based on system requirements, it is determined whether to start the secondary despreading process. If necessary, the local sequence generation offset address, compression ratio, and spread spectrum sequence truncation length are adjusted based on the despreading information; the compression ratio, cache start address, and received data truncation length of the buffer module are set, and the secondary despreading process is started. The data buffer module RxBuffer provides the time domain circular cyclic correlation despreading module with a compressed spread spectrum sequence of a complete symbol period at a low sampling rate and a truncated spread spectrum sequence of an incomplete symbol period at a high sampling rate based on effective storage of different compression ratios, starting storage locations, and storage lengths; The local spreading sequence generation module LocalCSSGen provides the time domain circular cyclic correlation despreading module with a compressed local spreading sequence of a complete symbol period and a truncated local spreading sequence of an incomplete symbol period based on different compression ratios and spreading sequence offset addresses; The time domain circular cyclic correlation despreading module RxDeCSS implements a secondary time domain circular correlation despreading mechanism that combines local coherent despreading of a compressed received spread spectrum sequence for a complete symbol period with local coherent despreading of a high sampling rate received spread spectrum sequence for an incomplete symbol period, and outputs final despread symbol information.

2. The system according to claim 1, wherein During the first despreading, the compression ratio that satisfies the storage of the complete symbol period sequence is configured. It is based on the system's buffer space BufferLen, the maximum FFT length FFTLen supported by the FFT module, and different spreading sequence length N configurations to meet the following requirements: 。 3. The system according to claim 1, wherein: The compression ratio of the data buffer module RxBuffer and the local spread spectrum sequence generation module LocalCSSGen is consistent with the sequence truncation length, and the second compression ratio is Not greater than the first compression ratio ,Right now .

4. The system according to claim 3, wherein: 。 5. The system according to claim 3 or 4, characterized in that The despreading parameter control module RxCtrlModul is based on the first despreading correlation peak position , and compression ratio , adjust the local sequence to generate the offset address LocalShift, the calculation formula is as follows: ， Where m is the calculated correction parameter, The first compression ratio.

6. The system according to claim 5, wherein: m is 2~10.

7. The system according to claim 2, wherein: In the truncation cycle fine despreading state, the truncation length Ntruc of the data buffer module RxBuffer and the local spread spectrum sequence generation module LocalCSSGen satisfies: truncation length , Indicates the second compression ratio.

8. The system according to any one of claims 1 to 3, characterized in that The calculation formula for outputting the final despread symbol information is as follows: ， Among them, LocalShift represents the offset address, Indicates the second compression ratio, PeakIdx 2 Indicates the correlation peak position of the secondary despreading, and SymValue indicates the symbol value obtained by despreading.

9. The system according to any one of claims 1 to 3, characterized in that The time domain circular cyclic correlation despreading module RxDeCSS performs the first despreading process, uses FFT to implement circular cyclic correlation, and completes the correlation peak Peak 1 and peak position PeakIdx 1 The search is based on the following formula: ， The time domain circular cyclic correlation despreading module RxDeCSS performs secondary despreading processing, uses FFT to implement circular cyclic correlation, and completes the correlation peak Peak 2 and peak position PeakIdx 2 The search is based on the following formula: , Among them, abs is the modulo processing; fft is the Fourier transform; ifft is the inverse Fourier transform; RxData_truc is the received data for the second despreading, and LocalCSS_trunc is the truncated sequence generated by LocalCSSGen for the second despreading, which is a partial truncation of the complete local despreading sequence.

10. A method for optimizing the complexity of logic circuits in a spread spectrum communication system, characterized in that: Using the system according to any one of claims 1 to 9, the method comprises: When the first despreading of the current spreading sequence is started, the despreading parameter control module RxCtrlModul configures the compression ratio that satisfies the storage of the complete symbol period sequence and the starting index of the initial spreading sequence, and starts the first despreading process. After the first despreading process, based on system requirements, it determines whether to start the second despreading process. If necessary, it adjusts the local sequence generation offset address, compression ratio, and spread spectrum sequence truncation length based on the despreading information. It also sets the compression ratio of the cache module, the cache starting address, and the received data truncation length, and starts the second despreading process. The data buffer module RxBuffer provides the time domain circular cyclic correlation despreading module with a compressed spread spectrum sequence of a complete symbol period at a low sampling rate and a truncated spread spectrum sequence of an incomplete symbol period at a high sampling rate based on effective storage of different compression ratios, starting storage locations, and storage lengths. The local spreading sequence generation module LocalCSSGen provides the time domain circular cyclic correlation despreading module with compressed local spreading sequences of complete symbol periods and truncated local spreading sequences of incomplete symbol periods based on different compression ratios and spreading sequence offset addresses; The time-domain circular correlation despreading module RxDeCSS implements a secondary time-domain circular correlation despreading mechanism that combines local coherent despreading of the compressed received spread spectrum sequence for a complete symbol period with local coherent despreading of the high sampling rate received spread spectrum sequence for an incomplete symbol period, and outputs the final despread symbol information.

11. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by a processor, the method for optimizing the complexity of logic circuits in a spread spectrum communication system according to claim 10 is implemented.

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