On the Enhancement of LDPC Codes in the IEEE 802.16 Physical Layer

In this paper we study low density party check (LDPC) codes used in the IEEE 802.16 physical layer standard. We introduce two novel techniques to enhance the performance of such codes. In the first technique, we use the binary parity check matrix proposed in the IEEE 802.16 standard, and propose a novel parity check matrix for LDPC codes over GF(4) with the non-zero entries chosen to maximize the entropy. We show that our proposed code outperforms the binary code proposed in the IEEE 802.16 standard over both AWGN and SUI-3 channel model. In our second technique, we use a high rate LDPC code, in a concatenated coding structure, as an outer code, with a convolutional code as an inner code. We compare the performance of such a concatenated code with the commonly used one utilizing Reed-Solomon codes over the standard SUI-3 channel model, and show better performance.