Optical Wireless Systems Channel Modelling

With the development of society, the users of mobile devices and electronic devices increase exponentially. As a result, the demand of high-performance communication system becomes more and more significant. Optical wireless communication (OWC) is an effective method to address the increasing number of internet users, which is a promising field. It is significantly important to understand the parameters and characteristics of communication channel if researchers want to design, generate, accomplish, and operate the OWC systems. In this paper, the propagation model discussed in optical wireless communication can be divided into two types: directed Line of Sight (LOS) propagation model and non-Line of Sight propagation model. In case of directed LOS, multipath reflection does not need to be addressed, which is easier to calculate the LOS channel gain. In case of non-Line of Sight propagation, there are some reflections produced from room ceilings and walls, which can be divided mainly into two methods: first order reflection and second order reflection. Based on the conventional diffuse systems and optical wireless systems with angle diversity receivers, the impulse response, delay spread and signal to noise ratio (SNR) will be calculated. In order to optimize the optical wireless system access point and wavelength allocation to users so as to maximize the sum rate offered to all users, the mixed-integer linear programming (MILP) model was proposed and developed.