Soft Information Assisted Phase Noise Estimation in Vector OFDM using Linear MMSE Receivers

Vector orthogonal frequency division multiplexing (V-OFDM) for single transmit antenna systems is a generalization of OFDM where single-carrier frequency domain equalization (SC-FDE) and OFDM are just two special cases. Phase noise in a V-OFDM system leads to a common vector block phase error (CVBPE) as well as an inter vector block carrier interference (IVBCI) effect. Severe performance degradation results if these two effects are not estimated and compensated for. In this paper blind and semi-blind phase noise estimation and compensation in a V-OFDM system is investigated by using the expectation maximization (EM) algorithm. This is motivated by the fact that conventional frequency domain phase noise suppression schemes based on pilot-aided CVBPE estimation and compensation are not spectrally efficient as the vector block size is increased. Two novel algorithms are proposed, one estimates the CVBPE only and the other estimates the entire phase noise sequence in the time-domain. Simulations show that with the proposed algorithms V-OFDM can outperform OFDM system with conventional data aided or soft information aided phase noise CPE correction.