The choice of cooperation opportunity and SER analysis in amplify-and-forward cooperative communications system
Zemin Liu · Journal of Circuits and Systems · 2010
Conventional half-duplex amplify-and-forward (AF) method always adopts cooperative communications model regardless the fading state of the channel, which makes insufficient use of the degrees of freedom of the system in a way. So, this paper discusses the problem about when to cooperate. In order to optimize the ergodic capacity of a two-user AF cooperative communication system, an improved AF (IAF) method is first proposed. Whether the IAF method adopting the cooperative model or not bases on the comparison about the instantaneous channel gains of source-to-destination with that of relay-to-destination. And then the approximately closed-form symbol-error-rate (SER) is derived. Finally, the system performances used IAF method are compared with that of AF with different power allocation schemes. Theoretical analysis and simulation results show that the IAF outperforms the AF method both in ergodic capacity and SER performance.