CCI mitigation using interference whitening in bandlimited micro-cellular BPSK systems

Cochannel interference mitigation in bandwidth efficient BPSK systems operating in slow, flat fading microcellular environments is considered. The desired and interfering users undergo Nakagami-m and Rayleigh fading, respectively. A whitening matched filter and fractionally spaced linear minimum mean square error equalizer are employed in the receiver. While whitening maximizes the signal-to-noise-plus-interference ratio, the whitening matched filter introduces intersymbol interference in the decision statistic. A minimum mean square error equalizer is used to combat the intersymbol interference. Important observations regarding the performance of the proposed receiver structure are made. The performance with Beaulieu-Tan-Damen pulse shaping is always better than with spectrum raised-cosine pulse shaping. The performance is considerably better than the conventional matched filter receiver under a variety of fading conditions for the desired user. The performance gain decreases with the severity of the fading of the desired user. When the cochannel interference is synchronous, the performance can approach the optimum single user performance by appropriately choosing the tap spacing and length of the equalizer.