Research On Visible Light Communication Technology Based On Energy Harvesting

In the face of massive connections in future wireless networks,traditional network communication technologies can hardly meet the user requirements of high speed,ultrareliability and low latency.Visible light communication(VLC)technology,as a new wireless communication technology,has great potential and advantages to provide high-speed and secure communication services by using visible light band for data transmission.In addition,because of the ability to transmit energy through visible light,VLC will become a promising green communication means in the future by using energy harvesting(EH)technology.Despite its many advantages,the current VLC system still faces the problem that the communication link is easily blocked and the communication range is limited.In this thesis,the research is carried out based on the above problems according to different usage scenarios,and the main work is as follows.(1)To address the problem of low coverage in outdoor VLC scenarios,this thesis proposes a VLC/radio frequency(RF)heterogeneous network with the aid of energy harvesting relays(EHR)to assist communication,and develops a network access strategy for users.The strategy is used to decide whether the user should access the network through a single-hop VLC-ONLY direct link or a two-hop RF/VLC link assisted by an EHR.To approximate the network topology,the network is modeled using a Poisson point process.The network outage rate related to the strength of the Poisson’s point process is derived using stochastic geometry theory,and the effect of different parameters on the network outage rate is discussed through simulation experiments.The results show that the proposed VLC/RF system can achieve a lower network outage probability compared to the VLC system alone.(2)To address the problem that the line-of-sight links are easily blocked by objects in indoor VLC scenarios,this thesis proposes the intelligent reflective surface(IRS)enhanced VLC system model and considers two types of users: information users for highspeed data communication and energy harvesting users for low-power applications.With the goal of maximizing the reachable rate and the energy harvesting demand of the energy harvesting users,this thesis designs a two-stage joint resource allocation algorithm based on the block coordinate descent(BCD)algorithm framework by jointly optimizing the power control,DC bias allocation and IRS association at the VLC access points.Simulation results show that the proposed algorithm has better performance compared with the benchmark algorithm,while experiments show that IRS can effectively improve the system performance and reduce the sensitivity of the VLC system to occlusions.