Iterative Decoding-Based Phase Estimation for OFDM Systems at Low Operating SNR

This paper proposes a new phase estimation algorithm for turbo-coded OFDM systems at low SNR. In the proposed algorithm, phase estimation process is implemented jointly with iterative decoding process. This algorithm uses extrinsic information at each decoding iteration to estimate OFDM carrier phase rotations instead of using pilots. The proposed algorithm iteratively estimates phase rotation at each OFDM carrier by averaging soft decision extrinsic information carrier by carrier. The algorithm significantly reduces pilot insertion and thus, it is suitable for low operating SNR systems. Simulation results show that the proposed algorithm achieves significantly improved phase estimation compared to the conventional pilot assisted phase estimation and it converges to perfect phase estimation case.