Performance Analysis of PAM-DMT Under Double sided Signal Clipping in IM/DD Based Systems

Due to the widespread of Light Emitting Diode (LED)s that are ambidextrous in performing simultaneous illumination and communication, Visible Light Communication (VLC) with huge bandwidth has been evolved as a new wireless technology to deliver high data rates. However, these LEDs possess nonlinear behaviour, come as front end devices in a VLC system, and cause clipping on the modulated signal that affects the performance. In this work, the effect of dual side signal clipping in Optical Wireless Communication (OWC) systems based on Pulse Amplitude Modulated-Discrete Multi-Tone (PAM-DMT) is investigated. Improper DC biasing and power rating of the front end device decides the amount of clipping. The analytical expression for the clipping noise power and an exact Bit Error Rate (BER) expression under clipping noise is presented. Along with BER performance, Peak-to-Average Power Ratio (PAPR) performance under the impact of uncorrelated clipping noise that arises from dual side clipping for various modulation orders, under different conditions is also examined.