Alamouti Coded OFDM in Rayleigh Fast Fading Channels - Receiver Performance Analysis

In this paper, the receiver performance of Alamouti coded orthogonal frequency division multiplexing (OFDM) systems is analyzed. When the channel is not constant during the period of Alamouti codeword transmission, the conventional linear maximum likelihood (ML) receiver suffers from performance degradation. We use three different receiver combining methods and study the error performance. The sensitivity of different receivers is investigated by varying the correlation coefficient. Our results can be easily extended to be applicable to other block coded OFDM schemes with different antenna configurations. The performance loss in linear ML receiver can be partially improved by employing a decision-feedback strategy. In the decision feedback steps preliminary decisions are used to subtract the intercodeword coupling. However this increases the computational complexity of the receiver.