A Design Of An Adaptive Decision Feedback Equalizer For Digital Mobile Communication Systems

Abstract

This paper describes a design of an adaptive decision feedback equalizer (DFE) using Kalman filter algorithm and an assessment of its performance by computer simulation over fading multipath channels. The adaptive equalizer consists of a fractionally spaced decision feedback equalizing part and a tap-coefficient-update part. Tap coefficients are updated according to the square-root Kalman filter algorithm, resulting in stable operation in spite of the reduced quantization number of hits in the algorithm. Key design parameters are considered such ns the allowable frame timing offset and input signal level variation and the performance of the bit error probability is evaluated for various fading multipath conditions. I t is shown that the adaptive DFE investigated here is effective over fast timevarying fading multipath channels.