Channel estimation errors and pilot power allocation for wireless systems with antenna arrays

This paper discusses wireless systems using antenna arrays at both the transmitter and receiver. Spacetime coding is used to exploit the parallelism of the radio channels formed. Theoretical results on signal-to-noise ratio (SNR) degradation due to imperfect channel estimation are used to determine the optimum ratio of pilot to data symbols to be used in a Rayleigh fading environment. Exact results initially are obtained for the single transmit antenna case. These results are then extended to multiple transmit antennas, using analysis of an upper bound on error probability. The results can be used for any SNR, for any channel Doppler frequency and for any transmitter and receiver array size.