Multi-user THSS system for visible light links

In this paper, a system based on time-hopping spread spectrum techniques for indoor visible light communications is studied via simulation. A 2-PPM modulation scheme is selected because it yields good results in wireless optical communications. Furthermore, the system allows for selecting the number of pulses per symbol to be transmitted and makes use of an optimum maximum-likelihood receiver for A WGN channels with the ability to choose between hard- or soft-decision decoding. The system designed allows for comparing the performance based on the computation of the bit error rate as a function of the pulse energy to noise power spectral density ratio, for different configurations in single-user and multi-user environments.