Multiuser Common Phase Error Estimation for Uplink OFDMA Communications

Performance degradation due to Wiener phase noise which causes both common phase error (CPE) and inter-carrier interference (ICI) is a crucial challenge to the implementation of multi-carrier communication systems. In uplink OFDMA transmissions, simultaneous transmitted user signals give rise to multiple phase noise where conventional phase noise correction methods can not be directly applied since they target at single phase noise. To solve this problem, a unified phase noise corrupted uplink OFDMA signal model which can apply to any sub-carrier assignment schemes is derived. According to this model, two algorithms based on least-square and maximum likelihood criteria are proposed respectively. Performance simulations are given to illustrate the effectiveness of the proposed algorithms for uplink OFDMA systems. Our study also shows that interleaved scheme suffers more ICI than subband based scheme under phase noise environment.