Joint network/channel coding for bandwidth-efficient multi-user ARQ

This paper presents a novel bandwidth-efficient joint network/ channel coding approach for multi-user ARQ where network coding is employed to combine retransmissions to several users. It features trellis-coded modulation (TCM) and iterative network/channel decoding. We provide guidelines for optimizing the TCM encoder to enable a high throughput and match the network code to the TCM encoder such that convergence of the iterative decoder is achieved. Our results show that the proposed scheme significantly outperforms the conventional ones. At the same time the amount of feedback and the decoding complexity per user are greatly reduced.