Comparison between three methods of pilot-aided demodulation

Abstract

Coherent optical and radio systems suffer from phase noise introduced by radio frequency oscillators or lasers used for up-conversion and down-conversion. In strong phase noise conditions, cycle slips of the recovered carrier appear, leading to error floor. Pilot symbols are known to be an effective countermeasure against cycle slips. In this paper we compare the performance of three pilot-aided demodulation schemes. The results show that the trellis based method outperforms the competitors.