Performance analysis of pilot symbol aided QAM for Rayleigh fading channels

We derive upper bounds on the symbol error probability for a communication system that sends quadrature amplitude modulated data over a frequency-flat Rayleigh fading channel. We first derive simple error bounds in terms of a key parameter, namely, the channel estimation error variance. We move on to derive expressions for the this parameter for a pilot symbol assisted channel estimation scheme. The estimation error variance, and thus the symbol error probability, are expressed succinctly in terms of the statistics of the channel fading process, the frequency of insertion of pilot symbols, and the average signal-to-noise ratio.