Practical joint network-channel coding schemes for slow-fading orthogonal multiple-access multiple-relay channels

In this paper, we investigate cooperative strategies for the slow fading Orthogonal Multiple Access Multiple Relay Channel (OMAMRC), defined as follows: (1) Independent sources communicate with a single destination in the presence of multiple relays; (2) Each relay is half-duplex; (3) Orthogonal multiple access schemes (e.g., time-division based) are used by the sources and the relays; (4) The links between the different nodes of the MAMRC are subject to slow fading and additive white Gaussian noise. The cooperative strategies are based on Joint Network Channel Coding and Decoding (JNCC/JNCD) and Selective Decoding and Forward (SDF) relaying. SDF is a variant of Decode and Forward (DF) where the relays forward a deterministic function of the correctly decoded sources´ packets. JNCC/JNCD fully exploits the spatial diversity and redundancy residing in both channel and network codes. The receivers at the relays and at the destination are designed in such away that they benefit from the signals of the previously activated relays to better decode the sources. Simulations show the effectiveness of the proposed approach.