Design of Adaptive Equalizer Based on Variable Step LMS Algorithm

Adaptive equalizer is important in transmission of wireless communication. The equalizer using least mean square (LMS) algorithm is adopted. Simulation results show that step size influences the algorithm convergence and stability, which will significantly affect the performance of adaptive equalizer. The requirement of step for convergence speed, time-varying tracking accuracy and convergence precision is contradictory. Therefore, a variable step LMS algorithm is presented in this paper. Simulation results show that the convergence speed and stability of the variable step algorithm are superior to ordinary LMS algorithm; moreover, the variable step algorithm is proper to be applied in channel equalization in low SNR.