Channel Modeling and Signal Processing for Array-based Visible Light Communication System in Misalignment

TL;DR

This paper develops an optimized optical antenna design and advanced signal processing techniques for array-based visible light communication systems, significantly enhancing capacity and mobility in indoor environments.

Contribution

It introduces an optimal lens structure based on channel matrix conditioning and implements SIC and signal combining to improve VLC performance and mobility.

Findings

Channel capacity increases by over 5 times with alignment.

Capacity can reach up to 20 times under ideal conditions.

System mobility range is significantly expanded.

Abstract

This paper proposes an indoor visible light communication (VLC) system with multiple transmitters and receivers. Due to diffusivity of LED light beams, photodiode receive signals from many directions. We use one concave and one convex lens as optical antenna, and obtain the optimal lens structure by optimizing which corresponds to the minimum condition number of channel gain matrix. In this way the light emitted by different LED can be separated well from each other then minimize signal interference. However, interference increases in the case of system deviation, so we explore the system mobility. Then subsequent signal processing is carried out, including signal combining and successive interference cancellation (SIC). We combine the same signal received by different receivers to improve signal to interference noise ratio (SINR). And SIC can effectively restore interference and eliminate its impact. The simulation results show that channel capacity can be increased by more than 5 times and up to 20 times under the condition of receiver and transmitter alignment. In the case of movement, channel capacity can also be increased by about 4 times on average. Moreover, the mobile range of system is also significantly expanded.