Performance comparison of LDPC convolutional codes for memory size and encoder block size

In this paper, we compare the performance of some different types of time-invariant LDPC convolutional codes. We first confirm the well-known fact that the performance can be increased by increasing the number of delay, i.e. memory size. Then, we show by simulation that increasing the encoder block size may possibly increase the performance when the memory size is fixed, but this must be done properly. We show also that the performance is comparable when the constraint lengths are comparable regardless of memory size and encoder block size. For all these, we introduce a matrix expansion operation for various sizes of sub-matrices of H matrix to be used in the simulation.