Abstract: This paper evaluates the performance of fractal based variable step-size LMS (FB-VSLMS) algorithm on the estimation of multipath fading channel for nonstationary process transmission. The algorithm exploits the statistics of the nonstationary process and uses non-diagonal step-size matrix to design an adaptive LMS filter in order to estimate slow fading correlated Rayleigh channel, in particular, asymptotically stationary AR channel and Jakes channel. Analytic expressions of steady-state mean-square weight error (MSWE) and optimum step-size parameter are computed for these channels. The analytical expression of optimum step-size would enable reliable channel estimation in real time. Simulation results are compared with analytic expressions developed in this paper and are shown to agree with good conformity.

Keywords: Rayleigh fading channel, channel estimation, variable step-size LMS algorithm, nonstationary signals.

Pages: 230-241