Low complexity coded cooperation scheme using non binary LDPC codes

In this paper we present a coded cooperation scheme using nonbinary LDPC codes and show how it can be used in a multi-user environment to achieve full transmit diversity. It is well known that non-binary LDPC codes over GF(q) outperform binary LDPC codes, but at a cost of increased decoding complexity. To ensure that this scheme can be practically implemented, we demonstrate how the Belief Propagation (BP) algorithm can be simplified, with a complexity dependent only on the row weight of the parity check matrix and independent of the finite field size. We show that this decoding algorithm has only a small degradation in performance compared with BP decoding on quasi-static fading channels and present the performance of a coded cooperation scheme using non-binary LDPC codes defined in GF(4) and GF(16).