Performance of the adaptive baseband diagonalizer, a crosstalk canceller, in dual-polarized 16-QAM systems

An adaptive crosstalk canceller for dual-polarized 16-QAM systems in the presence of depolarization crosstalk is studied. Using the diagonalizer algorithm, the error probability, P_e, is calculated for crosstalk and signal-to-noise levels with uniform distributions of the crosstalk phase shift. The frequency of occurrence of P_e versus crosstalk phase shift, with crosstalk level as a parameter, and a three-dimensional plot of P_e as a function of the two crosstalk phase shifts are discussed. The receiver performance is acceptable in the presence of crosstalk levels that would otherwise render the system inoperable. However, depending on crosstalk level, P_e can have a range of 100:1 or more as different relative phase shifts are encountered. The steady-state performance of the diagonalizer receiver is found to be virtually identical with that of the mean-square error (MSE) receiver