Performance Analysis of Multi-DF Cooperative Communications over Nakagami-m Fading with Channel Estimation Error

The impacts of imperfect channel estimation on the Symbol-error-rate (SER) are investigated for multi-node Decode-and-forward (DF) cooperative communications, in which all the channels are described by Nakagami-m fading. The approximate SER expression is firstly provided by employing the Moment generating function (MGF) approach. By choosing the two most significant terms in the approximate SER, asymptotic SER is also derived at a high SNR regime for the insight of our approach. According to our analysis, an approximated diversity order of K ×m + m_SR can be achieved under the assumption of independent and identical distribution (i.i.d) channels and ideal channel estimation. In addition, error floor caused by channel estimation error is provided for the better understanding of channel estimation error. The exactness of theoretic SER expressions has been proved by numerical studies. Results also illustrate the negative impact of channel estimation error can be reduced by increasing the number of relays.