Decoding device and method

Abstract

The invention provides a decoding device and method. The method is suitable for the condition that periodic repeated code elements exist in original information code elements. The method comprises the steps that scrambled information code elements k0, k1, k2,..., kt-1, kt,..., km-1 with the length of m, the initial state M (0) of a long code generator and a state transition matrix B are received; constructing auxiliary data k0 ', k1', k2 ',..., k' 82 according to the scrambled information code elements k0, k1, k2,..., kt-1, kt,..., km-1; wherein ki '= ki + kt-1 + i, and i = 0, 1,..., 82; according to the auxiliary data k0 ', k1', k2 ',..., k' 82, the initial state M (0) and the state transition matrix B, a 42 * 42 full-rank matrix D is obtained through calculation; wherein the first behavior of the D is CBn, and then a scrambling code # imgabs0 # with the length of m is obtained through sequential analysis, the scrambling code obtained through analysis and scrambled information code elements k0, k1, k2,..., km-1 are subjected to modulo 2 addition operation, and an original information code element with the length of m is obtained.

Description

Technical Field

[0001] The present invention relates to the technical field of communication signal processing, and particularly to a scrambling blind parsing method in the case of an overly long pseudo-random sequence and periodic repetition of transmitted symbols, and specifically to a decoding device and method. Background Art

[0002] A pseudo-random sequence is a data sequence generated by a deterministic method but having similar random characteristics. On the one hand, this sequence can be predetermined and can be produced and replicated repeatedly; on the other hand, it has the random characteristics of a certain random sequence. Pseudo-random sequences are widely used in multiple fields due to their excellent characteristics. In code division multiplexing, code division multiple access, and spread spectrum communication, pseudo-random sequences are used as address codes and spread spectrum codes, which can improve the capacity, anti-interference ability, and access speed of the system. For example, in a CDMA system, pseudo-random sequences as spread spectrum codes have become one of the key technologies. Pseudo-random sequences have important applications in cryptography, such as generating key streams, randomization in the encryption and decryption processes, etc. However, it should be noted that due to the periodicity of pseudo-random sequences, they cannot be directly used in cryptographic systems that require unconditional security. In hardware and software testing, pseudo-random sequences can be used to generate test data to evaluate the performance and stability of the system. For example, in error code testing, pseudo-random binary sequences (PRBS) can be used to simulate a real communication environment and detect the bit error rate of the system. However, an overly long period of a pseudo-random sequence means that the elements in the sequence will repeat only after a long time. In the decoding process, if a specific element in the sequence needs to be used, and the position of this element in the sequence is far away, then a large amount of calculation or search is required to find it. This will make the decoding process very slow and inefficient.

[0003] Pseudo-random sequence descrambling is an important link in communication and data processing, which involves restoring a pseudo-random sequence that has been scrambled to the original data. When the original data is scrambled by a pseudo-random sequence with a relatively long period, to obtain the original data, it is necessary to first descramble the scrambled data. Conventional descrambling methods first need to clarify the generation rules of the pseudo-random sequence used in the scrambling process. This usually includes key parameters such as the length, period, and generating polynomial of the pseudo-random sequence. Secondly, according to the known scrambling rules, an inverse operation is performed on the received scrambled sequence. This usually means using the same pseudo-random sequence and algorithm as in the scrambling process, but performing the opposite operation (such as the inverse operation of modulo 2 addition). Finally, through the inverse operation, the pseudo-random components in the scrambled sequence can be gradually removed, thereby restoring the original data. However, this method has good results when solving pseudo-random sequences with relatively short periods, and it takes too long to solve pseudo-random sequences with relatively long periods. For example, at a rate of 1.2288 Mchip / s, the period is 2 42The pseudo-random sequence of 1 chip has a duration period of approximately 41.5 days. This means that it takes 41.5 days to complete one cycle. If each chip is used as the starting point for traversal search respectively, it will bring extremely high computational complexity and is physically difficult to achieve. Summary of the Invention

[0004] Aiming at the problem that the period of the pseudo-random sequence is too long and the computational amount of traversal search is too high, the present invention provides a decoding device and method.

[0005] In the first aspect, the present invention provides a decoding method. The period between two repeated code elements in the original information code element with a length of m is set as t, including:

[0006] Receiving scrambled information code elements k0, k1, k2,..., k t-1 , k t …, k m-1 , the initial state M(0) of the long code generator and the state transition matrix B;

[0007] According to the scrambled information code elements k0, k1, k2,..., k t-1 , k t …, k m-1 Constructing auxiliary data k0′, k1′, k2′,..., k8′2; where k i ′ = k i + k t-1+i , i = 0, 1,..., 82;

[0008] According to the auxiliary data k0′, k1′, k2′,..., k8′2, the initial state M(0) and the state transition matrix B, calculating to obtain a 42*42 full-rank matrix D; where the first row of D is CB n , and then sequentially parsing to obtain the scrambling code with a length of m

[0009]

[0010] Performing modulo 2 addition operation on the parsed scrambling code and the scrambled information code elements k0, k1, k2,..., k m-1 to obtain the original information code element with a length of m.

[0011] In the second aspect, the present invention provides a decoding device. The period between two repeated code elements in the original information code element with a length of m is set as t. The device includes:

[0012] A receiving module, configured to receive scrambled information code elements k0, k1, k2,..., k t-1 , k t …, k m-1, the initial state M(0) of the long code generator and the state transition matrix B;

[0013] An auxiliary data construction module for constructing auxiliary data k0′, k1′, k2′, …, k8′2 according to the scrambled information code elements k0, k1, k2, …, k t-1 , k t …, k m-1 ; where k i ′ = k i + k t-1+i , i = 0, 1, …, 82;

[0014] A calculation module for calculating a full-rank matrix D of 42 * 42 according to the auxiliary data k0′, k1′, k2′, …, k8′2, the initial state M(0) and the state transition matrix B; where the first row of D is CB n , and then sequentially parsing to obtain a scrambling code of length m

[0015]

[0016] A descrambling module for performing modulo-2 addition on the parsed scrambling code and the scrambled information code elements k0, k1, k2, …, k m-1 to obtain the original information code elements of length m.

[0017] In a third aspect, the present invention provides an electronic device, including a memory, a processor, and a computer program stored on the memory and executable on the processor, and the processor implements the method as described in the first aspect when executing the program.

[0018] In a fourth aspect, the present invention provides a non-transitory computer-readable storage medium, on which a computer program is stored, and the computer program implements the method as described in the first aspect when executed by a processor.

[0019] The beneficial effects of the present invention are:

[0020] Aiming at the problem that the period of the pseudo-random sequence is too long and the traversal search operation amount is too high, the present invention ingeniously utilizes the characteristic of periodic code element repetition of the transmission sequence, and through recursion, real-time processing of data descrambling can be realized when the state of the long code generator is unknown. Description of the Drawings

[0021] Figure 1 is the circuit structure of the long code generator;

[0022] Figure 2 is the flowchart of a decoding method provided by an embodiment of the present invention;

[0023] Figure 3Schematic diagram of a decoding device provided by an embodiment of the present invention;

[0024] Figure 4 Block diagram of an electronic device provided by an embodiment of the present invention. Detailed implementation manners

[0025] To make the objectives, technical solutions, and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0026] The schematic diagram of the long code generator applicable to the decoding method provided by the present invention is as Figure 1 shown. The upper part represents that a 42-bit linear shift register generates a pseudo-random sequence; then, the pseudo-random sequence and a 42-bit long sequence mask perform modulo-2 addition operation to generate a long code. Among them, the mask can be used to hide some parts of the original symbol data, and the composition of the mask is different in different communication systems.

[0027] The present invention aims to propose a fast and accurate long code blind parsing algorithm in the case where there are periodic repeated symbols in the original information symbols. The present invention recursively derives the state of the pseudo-random sequence, and then de-scrambles the data according to the characteristic that there are periodic repeated symbols in the original information symbols. The present invention avoids traversing and searching the data, thereby laying a solid foundation for real-time de-scrambling of long codes in engineering applications.

[0028] As Figure 2 shown, an embodiment of the present invention provides a decoding method, including the following steps:

[0029] S101: Receive the scrambled information symbols k0, k1, k2,..., k t-1 , k t ..., k m-1 of length m, the initial state M(0) of the long code generator, and the state transition matrix B;

[0030] S102: Construct auxiliary data k0′, k1′, k2′,..., k8′2 according to the scrambled information symbols k0, k1, k2,..., k t-1 , k t ..., k m-1 ; where k i ′ = k i + k t-1+i , i = 0, 1,..., 82;

[0031] S103: Calculate a full-rank matrix D of 42 * 42 based on the auxiliary data k0′, k1′, k2′, …, k8′2, the initial state M(0), and the state transition matrix B; the first row of D is CB n , and then sequentially parse to obtain a scrambling code of length m

[0032]

[0033]

[0034] S104: Perform modulo-2 addition on the parsed scrambling code and the scrambled information code elements k0, k1, k2, …, k m-1 to obtain the original information code elements of length m.

[0035] Aiming at the problem that the period of the pseudo-random sequence is too long and the traversal search operation amount is too high, the present invention cleverly utilizes the characteristic of periodic code element repetition of the transmission sequence, and through recursion, real-time processing of data descrambling can be achieved when the state of the long code generator is unknown.

[0036] To prove the rationality of the parsing method provided by the present invention, the parsing method of the present invention is further elaborated and deduced as follows.

[0037] Without loss of generality, assume that the initial state M(0) of the linear shift register is known, and the state transition matrix of the pseudo-random sequence is B, then the next state of the pseudo-random sequence can be expressed as:

[0038] M(1) = BM(0) (1)

[0039] Among them, the state transition matrix B can be expressed as:

[0040]

[0041] Among them, b1, b2…, b 41 represent the feedback coefficients of the linear shift register.

[0042] Accordingly, the nth state of the pseudo-random sequence can be expressed according to the state transition matrix as:

[0043] M(n) = B n M(0) (3)

[0044] Set C to represent a 42-bit long sequence mask, then the scrambling code y output by the long code generator can be expressed as:

[0045] y = CM(n) (4)

[0046] Assume that the original information code elements of length m are a0, a1, a2…, a t-1 , at …, a m-1 , where t is the period of the interval between two repeated symbols, and at the same time, scrambled codes y0, y1, y2…, y t-1 , y t …, y m-1 are generated. Therefore, the scrambled code can be rewritten as:

[0047] y i = CM(n + i) (5)

[0048] It is known that the data scrambled by the pseudo-random sequence long code is k0, k1, k2,…, k t-1 , k t …, k m-1 . If the period of the adjacent repeated symbol interval is t, that is, a i = a i+t-1 , so there is

[0049] k0′ = k0 + k t-1 = x0 + x t-1 + y0 + y t-1 = y0 + y t-1 (6)

[0050] Therefore, combining the above formula, we have:

[0051] k0′ = C[M(n) + B T-1 M(n)] (7)

[0052] Then, taking k0′, k1′, k2′,…, k4′1, we have:

[0053]

[0054] Among them, D is a full-rank matrix of 42*42, which is a parameter matrix containing the long code mask and the system delay. To solve the D matrix, continue to construct the following formula:

[0055]

[0056] So,

[0057]

[0058] Since the information on the right side of the equal sign is known, the matrix D can be obtained; and it is known that the first row of D is CB n , so we can sequentially obtain Finally, by performing modulo 2 addition on the obtained data and the scrambled data k0, k1, k2,…, k t-1 , k t …, k m-1 , the descrambling of the data can be realized.

[0059] The present invention is applicable to the case where the original transmitted symbol has periodic symbol repetition. By utilizing the recurrence of the pseudo-random sequence state and the periodic repetition characteristic of the original symbol, the traversal search of data is avoided.

[0060] Based on the same inventive concept, as Figure 3 shown, the present invention provides a decoding device, including a receiving module, an auxiliary data construction module, a calculation module, and a descrambling module.

[0061] The receiving module is used to receive the scrambled information symbols k0, k1, k2, …, k t-1 , k t …, k m-1 , the initial state M(0) of the long code generator, and the state transition matrix B; the auxiliary data construction module is used to construct auxiliary data k0′, k1′, k2′, …, k8′2 according to the scrambled information symbols k0, k1, k2, …, k t-1 , k t …, k m-1 ; where, k i ′ = k i + k t-1+i , i = 0, 1, …, 82; the calculation module is used to calculate a full-rank matrix D of 42 * 42 according to the auxiliary data k0′, k1′, k2′, …, k8′2, the initial state M(0), and the state transition matrix B; where, the first row of D is CB n , and then sequentially parse to obtain the scrambled code of length m The descrambling module is used to perform modulo-2 addition operation on the parsed scrambled code and the scrambled information symbols k0, k1, k2, …, k m-1 to obtain the original information symbols of length m. Where, the matrix D is represented as follows:

[0062]

[0063] Aiming at the problem that the pseudo-random sequence period is too long and the traversal search operation amount is too high, the device of the present invention cleverly utilizes the characteristic of periodic symbol repetition of the transmission sequence. Through recurrence, real-time processing of data descrambling can be realized when the state of the long code generator is unknown.

[0064] Figure 4 Illustrates a schematic diagram of the physical structure of an electronic device, as Figure 4As shown in the figure, the electronic device may include: a processor 401, a communications interface 402, a memory 403, and a communication bus 404. Among them, the processor 401, the communications interface 402, and the memory 403 complete communication with each other through the communication bus 404. The processor 401 may call logical instructions in the memory 403 to execute a decoding method, which includes: receiving scrambled information code elements k0, k1, k2, …, k t-1 , k t …, k m-1 , the initial state M(0) of the long code generator and the state transition matrix B; according to the scrambled information code elements k0, k1, k2, …, k t-1 , k t …, k m-1 to construct auxiliary data k0′, k1′, k2′, …, k8′2; where k i ′ = k i + k t-1+i , i = 0, 1, …, 82; according to the auxiliary data k0′, k1′, k2′, …, k8′2, the initial state M(0), and the state transition matrix B, calculate a 42*42 full-rank matrix D; where the first row of D is CB n , and then sequentially parse to obtain a scrambling code of length m Perform an exclusive OR operation modulo 2 on the parsed scrambling code and the scrambled information code elements k0, k1, k2, …, k m-1 to obtain the original information code elements of length m. Among them, the matrix D is represented as follows:

[0065]

[0066] In addition, when the above logical instructions in the memory 403 are implemented in the form of software functional units and sold or used as independent products, they may be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art or a part of this technical solution, may be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. And the aforementioned storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0067] An embodiment of the present invention further provides a computer program product. The computer program product includes a computer program stored on a non-transitory computer-readable storage medium. The computer program includes program instructions. When the program instructions are executed by a computer, the computer can execute a decoding method provided by each of the above method embodiments.

[0068] An embodiment of the present invention further provides a non-transitory computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, it implements a decoding method provided by each of the above method embodiments.

[0069] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0070] 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 them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present invention.

Claims

1. A decoding method, characterized in that, Set the period between two repeated code elements in the original information code elements of length m as t, including: Receive the scrambled information symbols k0, k1, k2, …, k of length m t-1 , k t …, k m-1 , the initial state M(0) of the long code generator and the state transition matrix B; According to the scrambled information symbols k0, k1, k2, …, k t-1 , k t …, k m-1 construct auxiliary data k0′, k1′, k2′, …, k8′2; where, k i ′ = k i + k t-1+i , i = 0, 1, …, 82; Calculate a full-rank matrix D of 42×42 based on the auxiliary data k0′, k1′, k2′, …, k8′2, the initial state M(0), and the state transition matrix B; the first row of D is CB n , and then sequentially parse to obtain a scrambling code of length m Perform modulo-2 addition on the obtained scrambling code and the scrambled information symbols k0, k1, k2, …, k m-1 to obtain the original information symbols of length m.

2. A decoding device, characterized in that, Set the period between two repeated code elements in the original information code elements of length m as t, and the device includes: A receiving module, configured to receive scrambled information code elements k0, k1, k2, …, k t-1 , k t …, k m-1 , the initial state M(0) of the long code generator and the state transition matrix B; An auxiliary data construction module for constructing auxiliary data k0′, k1′, k2′, …, k8′2 according to the scrambled information code elements k0, k1, k2, …, k t-1 , k t …, k m-1 ; where k i ′ = k i + k t-1+i , i = 0, 1, …, 82; A calculation module, configured to calculate a full-rank matrix D of 42×42 based on the auxiliary data k0′, k1′, k2′, …, k8′2, the initial state M(0), and the state transition matrix B; wherein the first row of D is CB n , and then sequentially parse to obtain a scrambling code of length m The descrambling module is used to perform modulo-2 addition operation on the parsed scrambling code and the scrambled information code elements k0, k1, k2, …, k m-1 to obtain the original information code elements of length m.

3. An electronic device, comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the method described in claim 1.

4. A non-transitory computer-readable storage medium storing a computer program thereon, characterized in that, When the computer program is executed by the processor, it implements the method described in claim 1.

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