Optimum designs for high mobility systems with channel estimation errors

This paper studies the optimum system designs of high mobility wireless communication systems with channel estimation errors. In high mobility systems, the accurate estimation and tracking of the fast time-varying fading channel is nontrivial, and the residual channel estimation errors might have significant impacts on the system performance. The impacts of channel estimation error on system performance are quantified through the development of the analytical symbol error rate (SER) by analyzing the statistical properties of the estimated channel coefficients. With the help of the asymptotic analysis of the channel estimation mean squared error, the SER is expressed as an explicit function of a number of system parameters, such as the maximum Doppler frequency, the percentage of pilots in the transmitted symbols, and the ratio of energy allocated between data symbols and pilot symbols. The optimum pilot percentage and energy allocation factor that minimize the SER are identified through analytical and numerical studies.