Channel Equalization for Filter Bank Based Transmultiplexer System for Wireless Communications

This paper studies the subband equalization issues of filter bank based transmultiplexer system for wireless communications. The zero ISI/ICI and minimum MSE conditions for subband equalization are formulated from a full-band equalizer in a simple way by utilizing multirate filter bank theory. Then a pointwise equalization method that uses a complex FIR filter is employed to approximate the conditions for each subband. In the formulation process a response jump phenomenon is found in previous work which limits the equalization performance. A two-step decimation equalizer structure is then proposed to eliminate the phenomenon and a polyphase representation is applied to keep the computational complexity unchanged. Simulation results performed in a quasistatic Rayleigh fading channel show that the proposed subband equalizer with two-step decimation structure outperforms the existing one-step decimation equalizers.