An adaptive channel estimation scheme for OFDM system with transmitter diversity

In this paper, an adaptive channel estimation scheme is proposed for space-time block coded orthogonal frequency division multiplexing (ST-OFDM) systems. In this scheme, a computationally efficient decoupled maximum likelihood (DEML) algorithm is used to estimate initial channel parameter values. Once the initial values are obtained, an adaptive algorithm is used to obtain more accurate channel estimate values. It is shown that the proposed channel estimation scheme can eliminate the error floor substantially and perform quite close to the system with perfect channel state information for nontime-selective fading channel. For time-selective fading channels, it has the ability to track the channel adaptively without training symbols.