Adaptive equalization scheme in dual diversity reception for digital mobile communication systems

This paper proposes an adaptive equalization scheme in dual diversity reception and assesses its performance by computer simulation over fading multipath channels. This scheme is composed of adaptive decision feedback equalizers (DFEs) in each diversity branch, a least-squares combiner (LSC) and a decision device. In the LSC, the output signals of DFEs are multiplied by controllable weights based on mean square error criterion and summed. The output of the LSC is applied to the decision device to obtain a receiver estimate of the transmitted sequence. The receiver estimate is applied to DFEs as the input of the feedback section and the reference of the tap coefficient-update algorithm. In the DFEs and the LSC, the tap coefficients are updated independently according to the Kalman algorithm. Such an arrangement of the scheme reduces the computational complexity compared with a conventional DFE transversal-combining diversity reception scheme. Simulation results confirm the effectiveness of this proposed scheme over fading multipath channels with transmission bit rate of 40 kbps and the maximum Doppler frequency of 160 Hz observed in 1.5 GHz-band digital mobile radio communication systems