Combined Equalization and Differential Detection Using Precoding

A new transceiver for data transmission over multipath fading channels employing precoding and differential detection is investigated. It comprises a precoder, a differential detector and a linear equalizer compatible with differentially coherent detection. During a startup phase, the channel is estimated from a known training sequence and subsequently relayed to the precoder at the transmitter. This combination effectively functions as a decision feedback equalizer (DFE) for differentially coherent demodulation. Simulation results using the LMS algorithm are presented for both differential BPSK and differential QPSK over a two path fading channel. The proposed system is able to equalize the fading channel with a performance very close to that of the conventional DFE for coherent demodulation.