HOS-BASED VARIABLE STEP VOLTERRA FILTER

In this paper, we are to develop a second-order LMS-type Volterra filter to reduce distortions of data transmission over analog telephone channels due the channel impulse response and inter-symbol interference (ISI). A novel approach for updating the linear and quadratic coefficients vectors of a second-order Volterra filter is presented. The innovative features of this algorithm provide distinct convergence treatment of the linear and quadratic Volterra filter kernels, and adaptive formulation for the convergence factors, hence providing a unique platform for both linear and nonlinear channel adaptive handling. Simulations are carried in an equalization set-up to compare the performance of this algorithm with conventional and variable step LMS algorithms. The obtained results show that this algorithm brings substantial increase in the convergence speed while keeping, to some extent, the simplicity of the conventional LMS algorithm. Considering the performance of the formulated algorithm, it could be a useful tool for adaptive equalization applications.