Abstract: The current analysis focuses on the influence of demodulation performance in multipath fading propagation environments, which results from the pilot power variation of pilot symbol assisted modulation M-PSK in orthogonal frequency division multiplexing systems. The pilot-to-data power ratio is optimized analytically, and the loss due to imperfect channel estimation is calculated. Theoretical and simulation results show that the optimum pilot-to-data power ratio is affected by the signal-to-noise ratio, Doppler frequency and interpolation size etc. Once the optimization parameter of pilot-to-data power ratio is used, system transmission power is minimum while still meeting the fixed bit error rate target.