A fuzzy-rule-based phase error detector

In modern digital communications, efficient synchronization techniques are required at the receiver side to fully exploit the potential of modulation/coding schemes without causing a bottleneck in the overall system performance. One of the fundamental function in the receiver is the phase recovery unit, which generally consists of a phase-locked loop (PLL). This paper shows how fuzzy logic can be used to improve the behaviour of PLLs. In particular, we have derived a fuzzy-rule-based phase error detector, which permits a decrease in the steady-state phase variance to be achieved.