Cycle Detection of LDPC Codes Based on Linked List
A cycle detection method of low-density parity-check(LDPC) codes is proposed based on linked list.A linked list is obtained by expanding the non-zero elements in the parity-check matrix layer by layer.All the cycles can be detected by comparing the nodes per layer with those of upper layers.The exact number of different length of cycles can be got by recording them and then the girth(the length of the shortest cycle) is known.The detail of the process is given and the complexity is analyzed.Simulation results show that the method is powerful to detect all the different cycles in parity-check matrix.It's also very useful to estimate the performance of LDPC codes and construct the parity-check matrix.