Research On Multi-user Resource Management Algorithm For Visible Light Communication Network Based On White LED

Visible Light Communication(VLC)is a deep coupling between illumination and communication.It provides high-speed network by providing light and dark flashing signals that are not noticeable by the human eye,such as Light Emitting Diode(LED),while providing indoor illumination.Network data transmission.Compared with wireless radio frequency communication,VLC has the advantages of low cost,large bandwidth,high security and fast signal transmission rate,which can greatly alleviate the problem of spectrum tension of radio frequency communication.However,in addition to these advantages,there are still two shortcomings in the VLC system:(1)Due to the linear propagation characteristics of visible light signals,the communication coverage area of a single LED is limited,so multiple LED lights are required to construct a VLC network.In order to avoid communication blind spots,the coverage areas of adjacent LEDs will overlap each other,and the performance degradation caused by Inter-Cell Interference(ICI)will greatly affect the system performance of the VLC network.(2)When there are multiple users in the VLC network,how to achieve effective optical bandwidth allocation and multi-user scheduling(MUS)is another important issue facing VLC.In view of the above problems,this paper uses white LEDs synthesized by multi-color light sources as indoor lighting and VLC signal transmitters.In the VLC downlink system,a user-centric(UC)optimal scheduling scheme based on user's quality of experience(QoE)is proposed.At the same time,for the optimization problem of different LEDs,this paper designs a new greedy algorithm to allocate optical bandwidth resources,and dynamically searches for the optimal matching link between visible access points and user equipment(AP-UE)based on the user's QoE value.The main work and innovation of the paper are as follows.1.This paper uses a multi-color light source synthesized white LED as indoor lighting and VLC signal transmission.Compared with ordinary LEDs,the white LEDs synthesized by multi-color light sources not only have excellent color rendering index,but also can realize VLC multi-channel parallel transmission,which greatly improves the signal transmission speed of the VLC system.To further analyze the illumination and signal transmission performance of multi-color synthetic white LEDs,this paper details the VLC system in R,G,B(Red,Green,Blue)3 colors and R,G,B,C(Red,Green,Blue,Cyan)4-color Light-wave resource allocation and MUS in two cases of synthetic white LED.2.This paper adopts the new network service evaluation method-QoE.Compared with the quality of service(QoS)provided by the network,QoE considers the overall performance of the network from the perspective of the UE.It is a service evaluation method based on the degree of UE recognition,which can better reflect the UE pair.Satisfaction with web services.On the basis of ensuring the quality of LED illumination,this paper proposes a based UE QoE optimal greedy scheduling algorithm to allocate visible light bandwidth resources and completely eliminate ICI in the scheduling process.Based on the UE QoE optimal greedy algorithm,the optimal UE QoE is selected in the scheduling process to establish an AP-UE connection,so that the total QoE value of the UE in the system is maximized.After the corresponding AP-UE link is established,the link with the interference is selected to be removed,so that there is no interference between the selected links of the VLC system.At the same time,the fairness between the MUS and the scheduled UE is considered in the resource allocation process.A large number of simulation results show that the greedy algorithm based on UE QoE optimization proposed in this paper can provide communication services for more UEs with complete elimination of ICI,and the fairness between scheduled UEs is better.3.This paper introduces a new spectrum resource domain-power domain.A multi-color synthetic white LED is a white light that makes the entire output constant by controlling the average power ratio of the signals in each LED.For white LEDs of R,G,B,and C 4 colors synthesis,the transmission power value of each color is not unique according to the color power control formula.Since the transmission power values of the four colors R,G,B,and C in each VLC AP are uncertain,in order to maximize the total QoE of the UE,it is necessary to optimize the transmission power of each color of each VLC AP in the process of bandwidth allocation of the optical wave.Therefore,based on the RGB three-color resource allocation,this paper proposes a UE-based QoE optimal multi-color resource allocation and power optimization scheduling algorithm.In order to solve the joint optimization problem of VLC AP transmission power optimization and visible light wave bandwidth allocation,this paper splits the joint problem into two independent problems of resource allocation and power optimization to optimize UE QoE.The simulation results show that the multi-color resource allocation and power optimization scheduling algorithm based on UE QoE optimal can provide better UE QoE and schedule more UEs.