Optimal power allocation of the DF cooperation system over imperfect Nakagami-m fading channels
Ming Gao · Journal of Xidian University · 2012
The impacts of power allocation under imperfect channel estimation on the symbol-error-rate(SER) are investigated for a cooperative network with multiple decode-and-forward(DF) relays over Nakagami-m fading.First,the approximate SER and asymptotic SER for M-QAM are provided by using the Theorem of Total Probability and the moment generating function(MGF).Then based on the presented compact asymptotic SER,the optimal power allocation is transformed to a typical convex optimization problem so that the optimal power allocation is reached to minimize the SER under the total power constraints.Simulations show that compared to the uniform allocation scheme,optimal power allocation scheme can significantly improve the performance of the cooperative system at the low to medium SNR,but can not improve the error floor at the high SNR under the imperfect channel estimation.