MSE Adaptive Baseband Canceller Performance in Dual-Polarized 16-QAM Systems

The application of an adaptive baseband canceller to dual-polarized 16-QAM systems operating in the presence of moderate to severe crosstalk is considered. Concentrating on a method which minimizes the mean square error in the estimation of received symbol values, a computational method is presented by means of which exact values of symbol error probability, Pe, can be easily obtained for any specific values of relative crosstalk phase shift. Using this method, results are obtained which predict Pe versus crosstalk and signal-to-noise levels for uniform distributions of the crosstalk phase shift angles. Results are given which show the frequency of occurrence of different Pe values for uniformly distributed crosstalk phase shifts, and which show the maximum, minimum, and average values of Pe over all values of relative phase angles. The receiver performance is seen to be acceptable, so far as average Pe is concerned, in the presence of crosstalk levels that would make the system totally inoperable if no canceller were used. However, it is noted that for high crosstalk levels, values of Pe can have a range of 100:1 or more as different values of relative phase shift are encountered.