VLMS based Channel Estimator for OTFS VLC System

Abstract

Visible light communication (VLC) is an eco-friendly and low-cost emerging technology for beyond 5G communication systems. However, it has been found that the performance of visible light based communication system deteriorates significantly due to the non-linearity of light-emitting-diode (LED) and Doppler spread due to relative mobility between the transmitter and the receiver. In contrast to the conventional orthogonal frequency division multiplexing (OFDM) scheme, recently proposed orthogonal time frequency space (OTFS) modulation scheme addresses the problem of distortion due to mobility. However, LED non-linearity causes degradation in the channel estimation and overall bit error rate (BER) performance of the VLC system. These non-linear distortions significantly deteriorate the signal reception, thereby resulting in poor estimation of channel state information (CSI). Traditional linear channel estimation schemes such as zero-forcing (ZF) and minimum mean square error (MMSE) have been proposed for OTFS, however, they perform poorly in the presence of non-linearity. In this paper, we have analyzed the performance of OTFS employing Volterra least mean square (VLMS) based channel estimator for non-linear VLC system. Simulations performed over the mobile VLC channel model modelled by random way-point channel model indicate that OTFS with VLMS can be employed for channel estimation for VLC system impaired due to user mobility and non-linear LED characteristic. © 2022 IEEE.