Improved LED arrangement through outage probability minimization in LiFi communication systems

Abstract

In this paper, an improved method to arrange the light emitting diodes (LED) on the ceiling for an indoor visible light communication (VLC) system is proposed. More precisely, a LiFi-based connection is considered where several LEDs are placed on the ceiling of an office and communicate with several receiver (user) located randomly within the room area. It is proposed to find the optimal location of the LEDs by minimizing the outage probability at the user's location. Both cases of static and mobile users are addressed. First, the closed-form expression for the outage probability at the user's location is derived. Then, by minimizing the average outage probability, the optimal location of the LEDs is found. The numerical results show that the proposed LED arrangement outperforms the classically used uniform LED arrangement in terms of average outage probability at the receiver and reduces the necessary signal-to-noise ratio (SNR) to achieve a target average outage probability by about 3 and 2.2 dB for mobile and static users, respectively. They also show that the performance superiority of the proposed method over classical arrangement remains valid even under large estimation errors.