Research On VLC Access Technology And Communication System In Heterogeneous Celluar Network

Visible Light Communication(VLC)is more reliable communication that has emerged after wireless electromagnetic wave communication technology.As long as there are LED lighting facilities,wireless data signals can be transmitted using a convenient data transmission method.At present,optical channel modeling,full-duplex communication of uplink and downlink,converged architecture of heterogeneous networking,optimal network decision,and multi-user group decision access are key technologies in indoor converged heterogeneous networks based on visible light communication.How to provide optimal network access and optimal solutions in multiple candidate networks is a key issue that needs to be investigated according to the user's media data requirements.The contents of this dissertation are described as follows:First,we explain the research background and significance of VLC technology and indoor heterogeneous converged networks based on VLC,introduce the current research status of this technology,and analyze the characteristics of indoor visible light communication channels,i.e.,direct link characteristics and non-linear direct link characteristics.Moreover,we also analyze the process and decision method of multi-network dynamic switching,and introduce three algorithms based on indoor network decision and selection.Second,the indoor heterogeneous network channel model is established in view of the dynamic network access problem in the indoor VLC heterogeneous network architecture.The corresponding AHP algorithm and the weighted sum algorithm are designed to calculate the current best access network in the direct link area.Here,the degree method establishes a comparison judgment matrix,which is more in line with human thinking and judgment,and it is more suitable for QoE-based heterogeneous network access judgments.Moreover,an improved adaptive Hungarian algorithm is used to make it more suitable for the dynamic access of users in the indirect link area.Numerical simulation comparison with other schemes,it is proved that the proposed scheme can significantly reduce the number of overall network handovers.At the same time,it allows users to access the optimal network at their current location,which improves their QoE.Third,an indoor heterogeneous network communication hardware system based on VLC+WiFi is designed according to the indoor VLC heterogeneous network characteristics.For the design purpose,specific implementation methods and sustainable development significance of the hardware are explained.The system includes principles,processes of the following terminal and the receiving terminal.The circuit design of the system,the selection of components,the selection of chips and the calculation of some circuits are provided,and the PCB design layout and physical diagram of the hardware circuit are implemented.The hardware performs system testing and application scenario analysis.The analysis shows that the hardware communication system can be applied to most indoor visible light communication scenarios and meet the diversification of indoor visible light communication modes.Therefore,it has great potential in the future.