Decode-and-forward cooperative communications: Performance analysis with power constraints in the presence of timing errors

Applying cooperative techniques for saving transmit power and the related performance analysis with timing synchronization errors is discussed in this paper. The performance of a three-node decode-and-forward, power constrained, cooperative communication system over Rayleigh fading channels with timing synchronization error is considered here. The synchronization capabilities at the three nodes (the source, relay and destination), depending on the synchronization technique, number of samples used and the signal-to-noise-ratio at the nodes, play a vital role in the achievable overall quality of service (Bit error rate in this case) of the cooperative system. We present some simulation results to study and compare the performance using a computationally friendly near maximum likelihood timing synchronization method with signal-to-noise-ratio combining (SNRC) technique for the non-cooperative and cooperative scenarios. Our results show that power allocations at the source and relay nodes for transmissions, and the related timing errors at the relay and the destination nodes have some considerable effect on the bit error rate performance for power constrained cooperative communications.