Some remarks on the reduced constellation decision-directed blind phase correction

Phase offset recovery, besides channel equalization and timing synchronization, belongs to important task performed in physical layer of receivers. Correct information symbol detection is impossible without accurate phase estimation. The paper presents analysis of a decision-directed blind phase recovery schemes applied in communication systems with square QAM modulations. The cost function of the phase recovery scheme with a reduced constellation approach is considered as well as a way of its application in an adaptive algorithm. The algorithm operation is additionally controlled by an activation threshold. A comparison between different versions of decision-directed methods is made. The performed experiments show the influence of the activation threshold on the phase correction efficiency.