Phase Noise Estimation in OFDMA Uplink Communications

Phase noise is an important issue in OFDMA systems because it can degrade coherent demodulation and can destroy orthogonality among subcarriers. Models of phase noise sources and the corresponding effects in OFDMA systems are first described. There are various methods proposed to suppress phase noise in OFDM systems. The authors, then introduce a Pilot-Aided-Decision-Directed (PADD) approach for CPE estimation in OFDM systems. Conventional phase noise correction methods targeting at single phase noise, however, cannot be directly applied to uplink OFDMA transmissions because simultaneous transmitted user signals give rise to multiple phase noises.