Performance Analysis of Downlink MIMO-NOMA-Based Visible Light Communication System

Abstract

Recently, visible light communication networks have emerged as a possible option for data ac cess, primarily for indoor environments. The very high data rates, free from radio frequency interference, and low implementation cost behavior make them attractive for the next generation of indoor networking. But visible light communication technology supports only short-range data transmission, and hence the achievable data rate decreases rapidly with increasing distance between the transmitter and receiver. Additionally, developing a high data rate link in VLC system is difficult due to the narrow modulation bandwidth of LEDs. So that, it is essential to apply MIMO and Non-orthogonal Multiple Access to overcome such problems. In this thesis, a low complexity and efficient power allocation strategy was proposed for in door downlink MIMO-based visible light communication systems. Non-Orthogonal Multiple Access was applied on MIMO-VLC system to improve performance of edge users. Gener ally, the performance of the total sum rate of 4 × 4 MIMO VLC of k number of users were analyzed. Specifically, the sum rate, the sum rate gain, and the achievable rate of uniformly distributed users were analyzed for different power allocation techniques. MATLAB simula tion results depicted that the effectiveness of the proposed power allocation strategy than gain ratio power allocation schemes and normalized gain difference power allocation schemes for the large number of users. The proposed NOMA, NGDPA, and GRPA achieved a sum rate of 261.89 Mbit/s, 235.28 Mbit/s and 152.27 Mbit/s respectively at the edge of the system for six users. More specifically, the proposed NOMA attained an achievable sum rate of 18.36% and 65.98% as compared with the NGDPA approaches, and GRPA approaches in the 4×4 MIMO based visible light communication networks with eight uniformly distributed users. The future works can focus on finding the optimal user grouping and allocating power to each group. Ad ditionally, allocating the power according to quality of service is an open research problem in MIMO-NOMA-based VLC networks.