Construction method and device of quasi-cyclic low density parity check (LDPC) code

Abstract

The application provides a construction method and a device of a quasi-cyclic low density parity check (LDPC) code, belonging to the technical field of communications. The construction method comprises the following steps of: acquiring a complete cyclic difference set D={d1, d2, ..., dk}, wherein lambda of D is equal to 1, modulus v=k2-k+1, and lambda represents the number of two-tuples (di, dj) satisfying the formula di-dj=a in D, lis less than or equal to i, j is less than or equal to k, i is not equal to j, a is not equal to 0 (modv) and k is an even number; constructing an M*N shift matrix S(H) by using the D, wherein each position in S(H) is two-tuples (di, dj) selected from the D; and replacing the two-tuples (di, dj) at each position in M*N S(H) with a corresponding cyclic matrix Wm, n with weight being 2 and constructing a parity check matrix H of MP*NP, wherein Wm, n=I(di) + I(dj), the I(di) represents a cyclic permutation matrix obtained after a P*P unit matrix is shifted rightwards for di positions cyclically and P is equal to v. Under the same condition, the construction method can improve the performance of the LDPC code, is provided with a low error floor and has high coding convergence speed.

Description

technical field [0001] The present application relates to the field of communication technology, in particular to a method and device for constructing a quasi-cyclic low-density parity-check code. Background technique [0002] LDPC code (Low Density Parity Check Code, Low Density Parity Check Code), which was proposed by Dr. Robert G. Gallager in 1963, is a kind of linear block code with a sparse parity check matrix. It not only has good performance close to the Shannon limit, Moreover, the decoding complexity is low and the structure is flexible. It is a research hotspot in the field of channel coding in recent years. It has been widely used in deep space communication, optical fiber communication, satellite digital video and audio broadcasting and other fields. LDPC code has become a strong competitor of the fourth generation communication system (4G) channel coding scheme, and the coding scheme based on LDPC code has been adopted by the next generation satellite digital v...

AI Technical Summary

Problems solved by technology

For the (pseudo)random construction method, the codeword obtained by this method under the given parameters is not unique, and generally does not have quasi-cyclic structure characteristics, so it is difficult to apply in practice

However, the existing structural construction method generally adopts the method of geometric construction, the matrix scale is relatively large, and the matrix density is high, resulting in increased decoding complexity, which is difficult to meet the requirements of high-speed transmission systems, Internet of Things transmission systems, and communication storage systems. High standard requirements for the system and medium application environment of deep space communication

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