Coded cooperation using rate-compatible spatially-coupled codes

This paper investigates the use of rate-compatible spatially-coupled codes for coded cooperation. Transmitting to the same destination, two source nodes cooperate to combat block fading; using rate-compatible spatially-coupled codes, one source node relays additional parity-check bits for its partner´s latest transmission to provide cooperative diversity at the destination. Different families of spatially-coupled codes are generated by applying the edge spreading technique to several rate-compatible protograph-based block LDPC codes from the literature. Simulation of the outage behavior shows that, using spatially-coupled codes, system performance approaches the theoretical limit, regardless of whether the original underlying block LDPC codes were designed specifically for coded cooperation or not. The same result holds when windowed decoding, instead of decoding across the entire graph, is used to reduce decoding latency.