Improved iterative detection and achieved throughputs of OFDM systems under imperfect channel estimation

Abstract--Assuming imperfect channel estimation, we propose an improved detector for orthogonal frequency-division multiplexing (OFDM) systems over a frequency-selective fading channel. By adopting a Bayesian approach involving the statistics of the channel estimation errors, we formulate an improved maximum-likelihood (ML) detection metric taking into account the characteristics of the channel estimates. As a first step, we propose a modified iterative detector based on a maximum a posteriori receiver formulation which reduces the impact of channel uncertainty on the decoder performance, by an appropriate use of this metric. The results are compared to those obtained by using a detector based on a mismatched ML metric, which uses the channel estimate as if it was the perfect channel. In a second step, we calculate the information rates achieved by both the improved and mismatched ML detectors, in terms of achievable outage rates. These outage rates are compared to those provided by a ...

• Type: Journal
• Year: 2008
• Where: TWC
• Authors: Seyed Mohammad Sajad Sadough, Pierre Duhamel
• Keywords: Channel Estimation, Channel Estimation Errors, Detector, TWC 2008