Channel Estimation, Carrier Recovery, and Data Detection in the Presence of Phase Noise in OFDM Relay Systems

摘要

Due to its time-varying nature, oscillator phase noise can significantlydegrade the performance of channel estimation, carrier recovery, and datadetection blocks in high-speed wireless communication systems. In this paper,we analyze joint channel, \emph{carrier frequency offset (CFO)}, and phasenoise estimation plus data detection in \emph{orthogonal frequency divisionmultiplexing (OFDM)} relay systems. To achieve this goal, a detailedtransmission framework involving both training and data symbols is presented.In the data transmission phase, a comb-type OFDM symbol consisting of bothpilots and data symbols is proposed to track phase noise over an OFDM frame.Next, a novel algorithm that applies the training symbols to jointly estimatethe channel responses, CFO, and phase noise based on the maximum a posterioricriterion is proposed. Additionally, a new \emph{hybrid Cram\'{e}r-Rao lowerbound} for evaluating the performance of channel estimation and carrierrecovery algorithms in OFDM relay networks is derived. Finally, an iterativereceiver for joint phase noise estimation and data detection at the destinationnode is derived. Extensive simulations demonstrate that the application of theproposed estimation and receiver blocks significantly improves the performanceof OFDM relay networks in the presence of phase noise.