Simplified fuzzy stochastic gradient FIR adaptive equalizer for terrestrial HDTV transmission

Abstract

We present a simplified fuzzy stochastic gradient (SFSG) FIR adaptive equalizer for VSB/PAM terrestrial HDTV broadcasting, which is very suitable for FPGA or VLSI implementation. Finite impulse response (FIR) structure is adopted mainly due to its high throughput and easy hardware pipelining. The equalizer employs a fuzzy Takagi-Sugeno (TS) model to automatically regulate the step size of the descent gradient vector, with the goal of speeding up the convergence rate and lower excess mean square error (MSE). Specifically, it provides a general framework where one can easily incorporate additional safety rules or robust measures that will prevent the adaptive algorithm from becoming unstable and reacting to impulsive noise rapidly. Of greater significance is the drastic reduction in computational complexity by substituting multiplications with binary shift operations during tap-coefficient adaptation. Simulation results show that this equalizer provides 2.8 dB signal-to-noise ratio (SNR) improvement at a BER of 3.0/spl times/10/sup -6/ with respect to the conventional LMS DFE suggested by the Grand Alliance.