| 摘要 |
A computer-implemented system and method is for generating low-density parity check (LDPC) codes. One aspect of the invention includes a method for generating high rate LDPC codes that first constructs a matrix (H) of size mxn having m rows of check nodes and n columns of bit nodes. The matrix meets the following requirements: the weight of the j<-th >column equals aj; each row, r, has weight at most br; and the matrix H can be represented by a Tanner graph that has a girth of at least g>=g. The method then iteratively adds an (n+1)<th >column (U1) to matrix H, wherein the size of U1, is initially empty and is at most an+1, and wherein U1, comprises a set of i check nodes such that i is greater than or equal to 0 and i is less than an+1. The method then iteratively adds check nodes to U1. such that each check node does not violate predetermined girth and check-degree constraints. The matrix H is updated when a new column is added. The iterations are terminated if there are no new check nodes that do not violate the girth and check-degree constraints. The method can be modified to optimize various parameters, including the following cases: maximizing the rate for a fixed girth; maximizing the girth for a fixed rate; and maximizing the rate for a fixed girth and fixed length.
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