Distributed Turbo Block Codes in Wireless Relay Networks

This paper proposes distributed turbo block codes (DTBC) for wireless relay networks by using extended Bose, Chaudhuri, Hocquenghem (eBCH) codes as the constituent codes. The proposed technique assumes all channels are orthogonal and requires two phases to complete the transmission. In the first phase, the source broadcasts its information together with the parity bit sequence from the first code. The relay received the data from the source and process the data by using decode and forward protocol. The decoded systematic data at relay is interleaved and encoded by the second encoder. For the second phase, the parity sequence generated by the second encoder at relay is forwarded to the destination. In order to retrieve the original information bits, the signals received at destination from the source and relay are processed by using turbo iterative decoding technique, and for that purpose, soft-input soft-output Chase-Phyndiah (CP) algorithm is used for the decoding. We have conducted a series of simulations to study the effect of different iteration numbers at destination, different numbers of test pattern for Chase algorithm at destination and different locations of relay in a line network model. From our results, we showed that the proposed cooperative scheme outperforms the non-cooperative system as long as the relay is not too far away from the source. Finally, we presented the results of the proposed system by using different constituent codes with different minimum Hamming distances.