DISTORTION MINIMIZATION WITH ADAPTIVE FILTER FEEDBACK IN VISIBLE LIGHT COMMUNICATION

This paper presents a comparison of the signal estimation with the existing threshold approach and Adaptive feedback filter based approach. The adaptive feedback filter is a best estimation of optical signal even in the presence of noise. In optical communication system as the link length increases signal gets more and more distorted. So, it becomes difficult to estimate the signal. Adaptive feedback filter is a recursive filter, which provides an estimate with minimum mean square. Optical communication system modeling is done with state-space equation. The variances of the noise introduced at various stages (photo detector, amplifier) of the optical communication system are considered. Measurements of the bit error rate at various signal to noise ratios and also at different number of samples in a bit are observed, which represents that an increase in signal to noise ratio or the number of samples in a bit causes the bit error rate to decrease. Estimation of optical signal using adaptive feedback filter reduces the BER effectively.