Importance sampling analysis of digital phase detectors with carrier phase tracking

We introduce importance sampling techniques for the assessment of a class of open-loop digital phase modulation receivers with random carrier phase tracking in additive white Gaussian noise channels. We consider a symbol-by-symbol phase detector consisting of a bank of nonlinear stochastic filters tracking the random phase carrier and a decision algorithm driven by the filters' innovations. For the irreducible error floor assessment we use an importance sampling technique relying on large deviations principles that results in a multiple mode simulation density. The noisy operation of the receiver is addressed with an adaptive importance sampling technique. Simulations yield practically the same results obtained with conventional Monte Carlo with remarkable time gains.