Fading effects on antenna arrays in cellular communications

In future application of antenna arrays to wireless communications, it is envisioned that known signal waveforms (e.g., synchronization data stream) will be used for estimating the array response for all the relevant links. Once the array response is known, it will be used for separation and reconstruction of the unknown data stream. Since the array response matrix is estimated with finite precision, we examine the error effects on the signal reconstruction errors. The results are presented in the form of output signal-to-interference ratio (SIR) and output signal-to-noise ratio (SNR) for uncorrelated signals. We obtain closed-form expressions for the average output SNR and SIR for Rayleigh, Ricean, and Nagakami fading. It is shown that in the presence of slowly fading channels, the diversity advantage of the array decreases as the number of signals (or interferers) increases.