Impact of channel estimation errors in amplify-and-forward cooperative transmission

We analyze the impact of the channel estimation errors in amplify-and-forward (AF) cooperative communication systems over Rayleigh fading channels with multi-relays assisted. We derive the exact closed-form and the approximate expressions of the cumulative distribution function (CDF) of the received signal-noise-ratio (SNR) for each link. The variance of channel estimation errors varies for different values of the transmit SNR, dominated by the channel estimation quality order. We also present the approximate expression of the average symbol error rate (SER) under different levels of channel estimation errors by using the moment-generating function (MGF) based approach. Numerical results confirm that our theoretical analysis for SER is very accurate.