Effect of Imperfect Channel Estimation on Multi-Branch Cooperative Links in Fading Channels

The distributed cooperative diversity techniques are attracting a lot of attention as a means of advancing error performance and capacity. Transmit diversity is created when the selected stations assist a sender by relaying its information signal to the destination. The average symbol error rate (SER) of the distributed spatial diversity wireless cooperative system with L amplifying relays in Rayleigh fading and receiver maximum ratio combining (MRC) in the presence of channel estimation error is studied. Subsequently, we derive closed-form expressions for the SER of MRC in terms of the signal-to-noise (SNR) and the cross-correlation coefficient of the channel gain for the proposed cooperative amplify-and forward scheme. The SER and MSE formulas allow us clearly illustrate the imperfect channel state information on the performance of the distributed diversity system in fading environment. The loss of system performance is simulated in the presence of channel coefficient estimation error.