WIRELESS CHANNEL ESTIMATION ADAPTIVE FILTER COMPRISING DUAL LMS FILTER AND STEP SIZE CONTROL METHOD THEREOF

摘要

A wireless channel estimation adaptive filter including a dual LMS filter and a step size controlling method thereof are provided to improve performance of an LMS filter by controlling and setting the variable step size according to a tap coefficient. An NLMS(Normalized Least Mean Square) filter device is composed of a main NLMS filter(100) and an auxiliary NMLS filter(120). The main NLMS filter outputs an output vector by using a signal in a transmission terminal of a relay as an input signal. An error signal is obtained by adding a prediction value of the input signal and the output signal of the main NLMS filter. The tap coefficient of the main NLMS filter is updated to reduce the error signal. The auxiliary LMS filter updates the tap coefficient of the main LMS adaptive filter. The auxiliary NLMS filter includes the number of taps equal to the main NLMS filter.