Joint user decoding: a technique to enhance the benefits of coding in a multi-way relay channel

In this paper, a comparative analysis between joint and disjoint user decoding of the network and channel coded symbols in a multi-way relay channel is presented. The joint user decoding mechanism implements belief propagation algorithm to utilize the correlation between adjacent network coded symbols of user pairs, whereas, disjoint decoding disregards this correlation. This feature enables joint user decoding to support larger number of users than disjoint decoding in synchronous and asynchronous, additive white Gaussian noise and fading channels. Even, this novel mechanism allows almost the same level of average bit error rate performance for small and large number of users in asynchronous fading channel. Thus, to maximize the benefits of channel coding in practical propagation environments, joint user decoding in the relay node is essential.