On Throughput Performance of Decode and Forward Cooperative Relaying with Packet Combining and Arq

Cooperative Diversity can be used by wireless nodes to take the benefit of broadcast nature and inherent spatial diversity of wireless channel to relay messages for each others. This helps to propagate redundant signals over multiple paths, which can be used to combat the channel noise and fading effects. We investigate the use of packet combining in cooperative diversity scenario. In our approach we exploit this inherent spatial diversity alongwith the inherent time diversity in ARQ retransmissions. Further different channels have different fade levels or channel conditions. Maximal Ratio Combining of packets at the receiver improves the total Signal to Noise Ratio at the receiver, improving the throughput in wireless channel. Decode and Forward Relay can allow the opportunistic relay of the packets. In opportunistic relay of packets, the packet is relayed only when the direct transmission from source to destination fails. This saves the resources by avoiding the relay of packets, when not required. In this paper we propose the relaying scheme with packet combining at the destination. We investigate the BER and throughput performance of the scheme in AWGN and fading channel with and without MRC combining and compare them.