Performance analysis of dual-hop relay systems with single relay selection in composite fading channels

In this paper, we present novel and easy-to-evaluate expressions for the performance of dual-hop relaying with best relay selection operating over generalized-K fading channels. Since it is hard to find a closed-form expression for the probability density function (PDF) of the exact end-to-end signal-to-noise ratio (SNR) at the destination node even for the single dual-hop system with amplify-and-forward (AF) relaying, we use a tight upper bound value instead. Using the approximate value for the end-to-end SNR, closed-form expressions for the statistics of the SNR, the average bit and symbol error probabilities, and the ergodic capacity for the single dual-hop AF relay system, are derived. Moreover, assuming independent nonidentical fading conditions across multiple dual-hop relay links, we derive lower performance bounds for the single relay selection scheme with AF relaying. The final expressions are useful in the performance evaluation of AF opportunistic relaying in a generalized composite radio environment. Simulation results are also given to verify the analytical results.