Design And Simulation Of Joint Communication And Positioning In LED Visible Light Systems

With the increasing popularity of smart mobile terminals and the transformation and upgrading of the economy and society to digital,the social demand for communication and positioning is increasing.Therefore,the ability to provide accurate and effective location-based information services has become an essential function of all kinds of mobile intelligent devices.In deep indoor environments such as underground factories,underground warehouses,mines and so on,wireless signals are difficult to cover,and common LED light sources in these environments just provide conditions for visible light communication and positioning.Therefore,design of joint communication and positioning in visible light systems is one of the best solutions to the location-based information service problem in deep indoor environment.However,there are several challenges with this technology:(1)The signal content of visible light communication and visible light positioning transmission is completely different.In addition,visible light communication requires the same light source,while the latter requires the difference of light source,so the two cannot be directly integrated.(2)The system of visible light positioning should reduce the positioning error as much as possible on the one hand,and avoid too complex structure on the other hand.(3)The nonlinearity of LED leads to the mutual interference of different types of information in the design of joint communication and postioning in visible light systems.In order to solve the problem of location-based information service in deep indoor environment,this paper adopts the research method from shallow to deep to address these three challenges,and makes the following innovations:1.The structure of the visible light received signal strength positioning is simple,which meets the requirements of the design of joint communication and postioning in visible light systems.However,there are some problems in the algorithm,such as no solution of the positioning equation and large error of the output positioning coordinate.Therefore,the algorithm is improved.After obtaining multiple groups of positioning data at the positioning point,the improved algorithm uses K-means++clustering algorithm to divide the cluster,assigns different coefficients to centroid coordinates through multiple iterations,and finally outputs the positioning coordinates.Simulation results show that the improved algorithm improves the positioning accuracy of the receiving end.2.Aiming at the problem that visible light communication and visible light positioning cannot be fused directly,a visible light on-set fusion system based on orthogonal frequency division multiple access technology is designed.By allocating different sub-carriers for communication and positioning,the integrated transmission and receiving of communication positioning information is realized.Meanwhile,time division multiplexing technology is used to eliminate the mutual interference between different leds.3.In order to solve the problem that LED nonlinearity in the design of joint communication and postioning in visible light systems will lead to mutual interference between communication and positioning signals,linearity,decision feedback,Volterra series expansion and decision feedback equalization algorithm compensation based on Volterra series expansion are designed,and the performance differences of the four equalization algorithms are analyzed by simulation.Then the application scenarios of four equalization algorithms are discussed.In this paper,the design of joint communication and postioning in visible light systems is studied,which provides necessary technical support and reference for location-based information service in deep indoor environment,and also provides a new idea for the integration of communication and positioning in other wireless networks.