Estimation of Nakagami fading channel parameters with application to optimized transmitter diversity systems

An optimum power loading algorithm for transmitter diversity systems over correlated and unbalanced Nakagami (1960) paths and its performance evaluation under perfect channel estimation conditions are derived. In addition, various on-line estimators of the required Nakagami channel parameters for optimized power loading and the comparison of their mean square error via Monte Carlo simulations are presented. These estimators are used to obtain the performance of optimized transmitter diversity systems under imperfect channel estimation (ICE). These numerical results show that the diversity gain achieved by these optimized systems increases as the severity of fading decreases and as the degree of branch unbalance increases even under ICE. On the other hand, in weakly correlated and/or unbalanced branches, optimized transmitter diversity systems offer negligible gain or even losses compared to unoptimized systems because of the ICE