Rapid identification method, electronic device and system for error-containing m-sequence and Gold sequence

Abstract

The present invention discloses a method, electronic device and system for quickly identifying an m sequence containing an error code and a Gold sequence. The method comprises obtaining a spread spectrum code sequence of multiple users; selecting a spread spectrum code sequence of a user in turn for cyclic shift processing; performing point multiplication and summation processing on the corresponding position elements in the spread spectrum code sequence and the spread spectrum code sequence after the cyclic shift processing; normalizing the point multiplication and summation result; calculating the variance value of the normalized result; setting a decision threshold under different shift register levels, comparing the variance value with the decision threshold to determine whether the spread spectrum code sequence is a Gold sequence or an m sequence; when the spread spectrum code sequence types of all users are determined, the spread spectrum code sequence type determination results of all users are fused to obtain the final spread spectrum code sequence type identification result. The present invention avoids the use of various complex transformations, and has the advantages of simple and easy method, high recognition accuracy, and extremely fast operation speed.

Description

Technical Field

[0001] The invention relates to the technical field of blind estimation of satellite telemetry direct sequence spread spectrum signals, and in particular to a method, electronic equipment and system for quickly identifying an error-containing m sequence and a Gold sequence. Background Art

[0002] Direct sequence spread spectrum communication is the most commonly used spread spectrum technology, which has the advantages of strong anti-interference, low interception, good confidentiality, accurate timing and ranging, and easy implementation of code division multiple access. In direct spread spectrum communication, a binary periodic sequence generated by a linear feedback shift register (LFSR) is usually selected as the spread spectrum sequence, the most common of which are the m sequence and the Gold sequence. In the scenario of non-cooperative communication, it is necessary to estimate the spread spectrum code sequence used by the transmitter through various spread spectrum code sequence blind estimation algorithms. However, the estimated sequence often contains some bit errors under low signal-to-noise ratio. Therefore, it is necessary to correct the sequence containing bit errors and reconstruct a completely correct spread spectrum code sequence, thereby improving the blind despreading performance of the direct spread signal.

[0003] When the type of the spread spectrum code sequence at the transmitting end is unknown, its type needs to be identified in advance, and then different parameterized models can be established or different error correction algorithms can be designed for different sequence types. However, there are currently few methods for identifying m-sequences and Gold sequences containing errors. Existing literature proposes a method of using Walsh-Hadamard transform to estimate the generating polynomial of the unknown sequence type, and judge whether it is an m-sequence or a Gold sequence based on the length of the generating polynomial. However, this method requires setting different LSFR feedback coefficient series for Walsh transform, and it is also necessary to consider that the spread spectrum code sequence obtained by the blind estimation algorithm and the spread spectrum code sequence at the transmitting end may have reverse signs. The algorithm is too computationally intensive and seriously occupies computer memory.

[0004] In summary, there are currently two problems in the identification of m-sequence and Gold sequence types when there are bit errors. First, there are few existing reference methods; second, the existing algorithms are highly complex and the operation speed is too slow. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method, electronic device and system for quickly identifying an m sequence and a Gold sequence in the case of bit errors.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0007] In a first aspect, the present invention proposes a method for quickly identifying an error-containing m-sequence and a Gold sequence, comprising the following steps:

[0008] S1. Obtaining spreading code sequences of multiple users;

[0009] S2, selecting a user's spreading code sequence in turn to perform cyclic shift processing;

[0010] S3, performing point product summation processing on the spreading code sequence selected in step S2 and the elements at corresponding positions in the spreading code sequence after the cyclic shift processing in step S2;

[0011] S4, normalizing the calculation result obtained in step S3;

[0012] S5, calculating the variance value of the normalized result obtained in step S4;

[0013] S6, setting the decision threshold under different shift register levels, and comparing the variance value obtained in step S5 with the decision threshold; if the variance value is greater than the decision threshold, the spread spectrum code sequence is determined to be a Gold sequence; if the variance value is less than the decision threshold, the spread spectrum code sequence is determined to be an m sequence;

[0014] S7, judging whether the spread spectrum code sequence types of all users have been determined; if so, executing step S8; otherwise, returning to step S2;

[0015] S8. Perform fusion processing on the spread spectrum code sequence type determination results of all users to obtain a final spread spectrum code sequence type identification result.

[0016] Furthermore, the step S1 specifically includes:

[0017] A spreading code estimation algorithm is used to obtain M spreading code sequences of M users, where the spreading code sequence is expressed as [s1, s2, ..., s N ], N is the sequence length.

[0018] Furthermore, the step S2 is specifically divided into the following steps:

[0019] S21, select a user's spreading code sequence pn1 = [s1, s2, ..., s N ];

[0020] S22, cyclically shift the spreading code sequence pn1 by k bits to obtain the spreading code sequence pn2, expressed as

[0021]

[0022] Among them, k<0 means circular left shift, and k>0 means circular right shift.

[0023] Furthermore, the step S3 specifically includes:

[0024] The dot product sum is performed on the corresponding position elements in the spreading code sequence pn1 selected in step S2 and the spreading code sequence pn2 after the cyclic shift processing in step S2, which is expressed as

[0025]

[0026] Wherein, f(k) represents the sum of the products of the elements at corresponding positions in the spreading code sequence pn1 and the spreading code sequence pn2.

[0027] Furthermore, the setting of the decision thresholds under different shift register levels in step S6 specifically includes:

[0028] Calculate the corresponding number of shift register stages according to the length of the spread spectrum code sequence;

[0029] Then set the corresponding decision threshold according to the number of shift register stages.

[0030] Furthermore, the step S7 specifically includes:

[0031] According to the determination results of the spreading code sequence types of all users, the number of sequences determined to be m sequences is compared with the number of sequences determined to be Gold sequences; if the number of sequences determined to be m sequences is greater than the number of sequences determined to be Gold sequences, the spreading code sequence type is determined to be m sequence; otherwise, the spreading code sequence type is determined to be Gold sequence.

[0032] In a second aspect, the present invention further provides an electronic device, the device comprising:

[0033] a memory storing executable instructions; and

[0034] The processor is configured to execute the executable instructions in the memory to implement the above method.

[0035] In a third aspect, the present invention further proposes an identification system, the system comprising:

[0036] Identification device; and the electronic device mentioned above.

[0037] In a fourth aspect, the present invention further proposes a readable storage medium having executable instructions stored thereon, wherein the executable instructions implement the above method when executed by a processor.

[0038] The present invention has the following beneficial effects:

[0039] The present invention quickly identifies the m sequence and the Gold sequence containing errors, avoids the use of various complex transformations, and has the advantages of simple method, high recognition accuracy, and extremely fast calculation speed. At the same time, after identifying the type of the spread spectrum code sequence, the present invention can design different sequence error correction methods according to different types to obtain a spread spectrum code sequence with no errors, thereby improving the performance of blind despreading. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 The figure is a flow chart of a method for quickly identifying an m-sequence containing errors and a Gold sequence according to the present invention;

[0041] Figure 2 This is a recognition accuracy curve diagram of the m sequence and the Gold sequence at different bit error rates for a single user in an embodiment of the present invention;

[0042] Figure 3 This is a curve diagram of the fusion recognition accuracy rate under different bit error rates when there are four users in an embodiment of the present invention;

[0043] Figure 4 It is a schematic diagram of the physical structure of an embodiment of the present invention. DETAILED DESCRIPTION

[0044] The specific implementation modes of the present invention are described below to facilitate those skilled in the art to understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0045] like Figure 1 As shown, the embodiment of the present invention provides a method for quickly identifying an m-sequence containing errors and a Gold sequence, comprising the following steps S1 to S7:

[0046] S1. Obtaining spreading code sequences of multiple users;

[0047] In this embodiment, the present invention adopts a spreading code estimation algorithm to obtain M spreading code sequences of M users according to the spreading signal, where the spreading code sequence is represented as [s1, s2, ..., s N ], N is the sequence length.

[0048] S2, selecting a user's spreading code sequence in turn to perform cyclic shift processing;

[0049] In this embodiment, step S2 is specifically divided into the following steps:

[0050] S21, select a user's spreading code sequence pn1 = [s1, s2, ..., s N ];

[0051] The present invention selects a spreading code sequence of one user in turn from among M users to perform cyclic shift and subsequent processing until all users are processed.

[0052] S22, cyclically shift the spreading code sequence pn1 by k bits to obtain the spreading code sequence pn2, expressed as

[0053]

[0054] Among them, k<0 means circular left shift, and k>0 means circular right shift.

[0055] S3, performing point product summation processing on the spreading code sequence selected in step S2 and the elements at corresponding positions in the spreading code sequence after the cyclic shift processing in step S2;

[0056] In this embodiment, the present invention performs point product summation on the corresponding position elements in the spreading code sequence pn1 selected in step S2 and the spreading code sequence pn2 after the cyclic shift processing in step S2 to obtain the point product summation result of 2N-1 points, which is expressed as

[0057]

[0058] Wherein, f(k) represents the sum of the products of the elements at corresponding positions in the spreading code sequence pn1 and the spreading code sequence pn2.

[0059] S4, normalizing the calculation result obtained in step S3;

[0060] In this embodiment, the present invention normalizes the 2N-1 points of the product summation result f(k) obtained in step S3, which is expressed as

[0061] f(k)'=f(k) / max(f(k))

[0062] Among them, f(k)′ represents the normalized result.

[0063] S5, calculating the variance value of the normalized result obtained in step S4;

[0064] In this embodiment, the present invention calculates the variance value V for the normalized result f(k)′ obtained in step S4.

[0065] S6, setting the decision threshold under different shift register levels, and comparing the variance value obtained in step S5 with the decision threshold; if the variance value is greater than the decision threshold, the spread spectrum code sequence is determined to be a Gold sequence; if the variance value is less than the decision threshold, the spread spectrum code sequence is determined to be an m sequence;

[0066] In this embodiment, the present invention first sets the decision thresholds under different shift register levels, specifically including:

[0067] According to the length N of the spread spectrum code sequence, the corresponding shift register level is calculated as follows:

[0068] n=log2(N+1)

[0069] Then set the corresponding decision threshold T according to the number of shift register stages.

[0070] The threshold under the partial shift register can refer to Table 1.

[0071] Table 1. Threshold reference values under the partial shift register

[0072] Level n 6 7 9 10 11 Threshold T 0.016 0.0100 0.0023 0.00125 0.00065

[0073] The present invention further compares the variance value V obtained in step S5 with the set decision threshold T; if the variance value is greater than the decision threshold, i.e., V>T, then the spreading code sequence pn1 is determined to be a Gold sequence; if the variance value is less than the decision threshold, i.e., V<T, then the spreading code sequence pn1 is determined to be an m sequence.

[0074] S7. Determine whether the spreading code sequence types of all users have been determined; if so, execute step S8; otherwise, return to step S2;

[0075] S8. Perform a fusion process on the determination results of the spreading code sequence types of all users to obtain the final recognition result of the spreading code sequence type.

[0076] In this embodiment, step S7 specifically includes:

[0077] According to the determination results of the spreading code sequence types of all users, compare the number of sequences determined to be m sequences with the number of sequences determined to be Gold sequences; if the number of sequences determined to be m sequences is greater than the number of sequences determined to be Gold sequences, then determine the spreading code sequence type to be an m sequence; otherwise, determine the spreading code sequence type to be a Gold sequence.

[0078] The following uses a specific example to illustrate the effect of the recognition method of the present invention.

[0079] The present invention selects a spreading code sequence with a length of 2047, the number of stages of the corresponding shift register is 11, the decision threshold is set to T = 0.00065, and the bit error rate of the spreading code sequence ranges from 1% to 25%. 500 independent experiments are carried out. When there is a single user, the recognition correct rate curves of m sequences and Gold sequences under different bit error rates are obtained, as Figure 2 shown; when there are four users, each user uses the same type of spreading code sequence, and the fusion recognition correct rate curve under different bit error rates is obtained, as Figure 3 shown.

[0080] Based on the same concept, the embodiment of the present invention also provides a schematic diagram of an entity structure, as Figure 4As shown, the server may include: a processor 810, a communication interface 820, a memory 830 and a communication bus 840, wherein the processor 810, the communication interface 820 and the memory 830 communicate with each other through the communication bus 840. The processor 810 may call the logic instructions in the memory 830 to execute the steps of the identification method described in the above embodiment.

[0081] In addition, the logic instructions in the above-mentioned memory 830 can be implemented in the form of a software functional unit and can be stored in a computer-readable storage medium when it is sold or used as an independent product. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or the part of the technical solution, can be embodied in the form of a software product, and the computer software product is stored in a storage medium, including a number of instructions for a computer device (which can be a personal computer, a server, or a network device, etc.) to perform all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk and other media that can store program codes.

[0082] Based on the same concept, an embodiment of the present invention also provides a non-transitory computer-readable storage medium, which stores a computer program. The computer program includes at least one section of code, which can be executed by a main control device to control the main control device to implement the steps of the identification method described in the above embodiment.

[0083] Based on the same technical concept, an embodiment of the present application also provides a computer program, which, when executed by a main control device, is used to implement the above method embodiment.

[0084] The program may be stored in whole or in part on a storage medium packaged together with the processor, or may be stored in whole or in part on a memory not packaged together with the processor.

[0085] Based on the same technical concept, the embodiment of the present application further provides a processor, which is used to implement the above method embodiment. The above processor can be a chip.

[0086] The various embodiments of the present invention can be combined arbitrarily to achieve different technical effects.

[0087] In the above embodiments, it can be implemented in whole or in part by software, hardware, firmware or any combination thereof. When implemented by software, it can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, the process or function described in this application is generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from a website site, computer, server or data center to another website site, computer, server or data center by wired (e.g., coaxial cable, optical fiber, digital subscriber line) or wireless (e.g., infrared, wireless, microwave, etc.) mode. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that includes one or more available media integrated. The available medium can be a magnetic medium (e.g., a floppy disk, a hard disk, a tape), an optical medium (e.g., a DVD), or a semiconductor medium (e.g., a solid-state hard disk SolidStateDisk), etc.

[0088] Those skilled in the art can understand that to implement all or part of the processes in the above-mentioned embodiments, the processes can be completed by computer programs to instruct related hardware, and the programs can be stored in computer-readable storage media. When the programs are executed, they can include the processes of the above-mentioned method embodiments. The aforementioned storage media include: ROM or random access memory RAM, magnetic disk or optical disk and other media that can store program codes.

[0089] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for quickly identifying error-containing m-sequences and Gold sequences, characterized in that: The following steps are involved: S1. Obtaining spreading code sequences of multiple users; S2, selecting a user's spreading code sequence in turn to perform cyclic shift processing; S3, performing point product summation processing on the spreading code sequence selected in step S2 and the elements at corresponding positions in the spreading code sequence after the cyclic shift processing in step S2; S4, normalizing the calculation result obtained in step S3; S5, calculating the variance value of the normalized result obtained in step S4; S6, setting the decision threshold under different shift register levels, and comparing the variance value obtained in step S5 with the decision threshold; if the variance value is greater than the decision threshold, the spread spectrum code sequence is determined to be a Gold sequence; if the variance value is less than the decision threshold, the spread spectrum code sequence is determined to be an m sequence; S7, judging whether the spread spectrum code sequence types of all users have been determined; if so, executing step S8; Otherwise, return to step S2; S8, performing fusion processing on the spread spectrum code sequence type determination results of all users to obtain the final spread spectrum code sequence type identification result, The step S8 specifically includes: According to the determination results of the spreading code sequence types of all users, the number of sequences determined to be m sequences is compared with the number of sequences determined to be gold sequences; If the number of sequences determined to be m sequences is greater than the number of sequences determined to be Gold sequences, the spreading code sequence type is determined to be an m sequence; otherwise, the spreading code sequence type is determined to be a Gold sequence.

2. The method for rapidly identifying an error-containing m-sequence and a Gold sequence according to claim 1, characterized in that: The step S1 specifically includes: A spreading code estimation algorithm is used to obtain M spreading code sequences of M users, where the spreading code sequence is expressed as [s1, s2, ..., s N ], N is the sequence length.

3. The method for rapidly identifying an error-containing m-sequence and a Gold sequence according to claim 2, characterized in that: The step S2 is specifically divided into the following steps: S21, select a user's spreading code sequence pn1 = [s1, s2, ..., s N ]; S22, cyclically shift the spreading code sequence pn1 by k bits to obtain the spreading code sequence pn2, expressed as Among them, k<0 means circular left shift, and k>0 means circular right shift.

4. The method for rapidly identifying an error-containing m-sequence and a Gold sequence according to claim 3, characterized in that: The step S3 specifically includes: The dot product sum is performed on the corresponding position elements in the spreading code sequence pn1 selected in step S2 and the spreading code sequence pn2 after the cyclic shift processing in step S2, which is expressed as Wherein, f(k) represents the sum of the products of the elements at corresponding positions in the spreading code sequence pn1 and the spreading code sequence pn2.

5. The method for rapidly identifying an error-containing m-sequence and a Gold sequence according to claim 4, characterized in that: The step S6 of setting the decision thresholds under different shift register levels specifically includes: Calculate the corresponding number of shift register stages according to the length of the spread spectrum code sequence; Then set the corresponding decision threshold according to the number of shift register stages.

6. An electronic device, characterized in that: The device comprises: a memory storing executable instructions; and A processor configured to execute the executable instructions in the memory to implement the method according to any one of claims 1 to 5.

7. A recognition system, characterized in that: The system comprises: Identify the device; and The electronic device as claimed in claim 6.

8. A readable storage medium having executable instructions stored thereon, characterized in that: When the executable instructions are executed by a processor, the method according to any one of claims 1 to 5 is implemented.

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