Tuning of Extended-Resonance-Based Beamforming System for Visible Light Communication

Abstract

Visible Light Communication (VLC) uses the visible light emitted from Light Emitting Diode (LED) to transmit/receive data. Since the data is transmitted through the light, the connection speed is as fast as the speed of light, making it potential for very fast and massive data exchange. One thing that needs to be considered in VLC is that the power of the signal received by the sensor relies on the angle between the LED and the light sensor used as an antenna. The bigger the angle between LED and light sensor, the less optimal the signal power will be, and surely will affect the speed and reliability of the data transmission. To optimize the signal power, multiple photonic sensors will be used as an antenna to receive the light signal. The signal received from each photonic sensor will be combined to get higher signal power. However, to ensure that all signals from all photonic sensors are constructive to each other, all phase differences must be minimized. This paper proposes the extended-resonance-based beamforming system to be used to minimize the phase difference of the light signals in VLC application. A non-linear optimization method is used to tune the extended-resonance-based beamforming system. Given that the varactor is chosen carefully and sufficient enough, the non-linear optimization method such as active set, interior point, or sequential quadratic programming is able to tune the varactor, so that the beamformer will compensate the phase difference from the incoming signal.