Rate compatible low-density parity-check (LDPC) codes for H-ARQ systems

摘要

In one embodiment, the present application comprises a method and apparatus using progressive node puncturing. The present method and apparatus punctures the variable node (20) from the set of the non-punctured variable nodes (20), which is connected to the least number of check nodes (25) which are in turn connected to only one punctured variable node (20). If more than one such variable node (20) exists, then puncture the variable node (20) from the set which has the minimum number of punctured variable nodes (20) connected to its neighboring check nodes (25). If more than one such variable node (20) exists, we choose one variable node (20) at random. This whole process can be repeated, to get another code of the same desired rate but with another puncturing pattern. Then choose the code with the highest puncturing score. One advantage of progressive node puncturing is that it assigns the puncturing pattern for a certain rate such that further puncturing of this code would result in good higher rate codes. The designed codes will have good AWGN and erasure thresholds over the whole family range as well as good error floors. This is especially true for the higher rate codes in the family.