Cooperative partial retransmission scheme in incremental decode-and-forward relaying

In this paper, we present a novel hybrid automatic repeat request (HARQ) scheme for cooperative communication systems, called cooperative partial retransmission (CPR). The method is based on the retransmission of only a fraction of the original code word by the cooperating nodes. Based on the outage analysis, we derive the theoretical throughput expressions that are compared to numerical simulations using LDPC codes, showing that CPR outperforms regular cooperative HARQ techniques. Additionally, we show that the CPR throughput, even using a single relay, may be considerably larger than the throughput of a regular cooperative HARQ scheme using multiple relays. Finally, the energy consumption analysis of the schemes shows that CPR consumes less energy than regular cooperative HARQ, mainly due to the shorter retransmissions.