Performance analysis for Amplify-and-Forward relay selection with outdated channel estimates

Performance evaluation by considering outdated channel estimates in cooperative communications systems is formulated, with only Amplify-and-Forward (AF) relaying mode being considered in this paper. The approximation of closed-form solution for the system analysis is derived. The wireless relay channels between different nodes (e.g., source to relay, relay to destination, or source to destination) are assumed to suffer from an independent and identically distributed (i.i.d.) Rayleigh fading, and the potential performance gain obtained through cooperation and relay selection is analyzed as well. In the presence of high-speed objects, autocorrelation Jakes´ Model is employed to formulate the wireless fading channels. Both theoretical analyses and simulation results indicate the validity of the proposed method in terms of both the outage probability and the symbol error probability (SEP).With channel state information being known at the source node or with the Doppler Shift being negligible, a best-relay selection scheme can be performed to optimize both the outage probability and SEP. Numerical results finally validate the proposed analyses.