摘要
A channel estimation method is proposed for nmltiple-input multiple-output orthogonal frequency division muhiplexing （MIMO-OFDM） systems in time-varying fading channels. In this method, a decision-directed space-alternating generalized expectation-maximization （SAGE） algorithm is introduced to the tracking of time-varying fading. In order to improve the estimation performance of the SAGE algorithm, a low rank approximation method is presented by using the signal subspace of the channel frequency autocorrelation matrix. The study reveals that this method can be incorporated into the SAGE algorithm. Furthermore, a modified fast sub- space tracking algorithm is given to adaptively estimate the signal subspace by utilizing training OFDM blocks sent at regular interval. Simulation results demonstrate the considerable benefits of the proposed channel estimation method.
A channel estimation method is proposed for multiple-input multiple-output orthogonal frequency division multiplexing(MIMO-OFDM)systems in time-varying fading channels.In this method,a decision-directed space-alternating generalized expectation-maximization(SAGE)algorithm is introduced to the tracking of time-varying fading.In order to improve the estimation performance of the SAGE algorithm,a low rank approximation method is presented by using the signal subspace of the channel frequency autocorrelation matrix.The study reveals that this method can be incorporated into the SAGE algorithm.Furthermore,a modified fast subspace tracking algorithm is given to adaptively estimate the signal subspace by utilizing training OFDM blocks sent at regular interval.Simulation results demonstrate the considerable benefits of the proposed channel estimation method.
基金
Sponsored by the National Natural Science Foundation of China(Grant No.60572157)
the National High Technology Research and Development Program (863) (Grant No.2003AA12331007)
