Variance analysis of a hierarchical decision-directed phase detector for 16-QAM constellation

In this paper we introduce and describe an optimized phase detector suited to 16-QAM receivers which prevents ambiguous locking and performs relatively rapid acquisition. Based on a new decision scheme, the proposed phase detector outperforms a classical decision directed phase detector over a Gaussian channel. An analytical analysis of the proposed phase detector variance is carried out and validated by means of computer simulation.