A Simple Technique to Enhance Diversity Order in Wireless Fading Relay Channels

Relaying has proven to be an effective method of providing additional spatial diversity on wireless fading channels. This paper proposes a system of XORing at the relay with iterative maximum a posteriori (MAP) decoding at the destination. An XOR-relay offers an increased number of diversity paths, enabling the destination to construct a cycle- free decoding structure, and resulting in an enhanced diversity order. Simulation results clearly show that the proposed scheme approaches 3rd-order diversity in the topology of second diversity paths, with no need for additional resources.