Performance analysis of cooperative communications protocol using sum-product algorithm for wireless relay networks

Decode-and-forward cooperative communications protocol (DFP) allows single-antenna wireless users to obtain the powerful benefits of multi-antenna systems without physical antenna arrays. In addition, the sum-product algorithm (SPA) is extremely efficient for decoding the linear block codes with sparse parity-check matrix. Therefore, we propose a combination of DFP with the modified SPA where only the reliability of the received symbols at relay is forwarded to the destination, thus reducing considerably processing time but negligibly degrading BER performance. Such a combination also brings about both diversity gain and coding gain as the relay is at the appropriate positions. Computer simulations are performed to confirm the validity of the proposed protocol.