Research On Resource Allocation Algorithm In Visible Light Communication Nerwork

As the new century comes,the development of information technology has greatly enriched all the aspects of human life.Especially,thanks to the rapid development of wireless communication technology,people can be more convenient to access the vast amounts of information.According to the research,the demand for wireless communication transmission has a more than twice growth each year,of which 70%comes from the indoor users.But the reality,that the existing wireless LANs and Femetos have limited spectrum resources and constraints of electromagnetic interference,makes it difficult to enhance the capacity of wireless networks to meet the growing business need.As a new indoor wireless access technology,visible light communications has many advantages,such as rich spectrum resources,no interference to traditional networks,low power consumption and strong confidentiality.Meanwhile,the lighting as an indispensable demand for life and work,has spread into each home,office,hospital and airport.Visible light communication,which is a combination of lighting and communication,is considered to have a great prospect.Currently,the research of VLC is mainly focused on transmission technology and the data rate of point-to-point transmission has reached lOGbps.Therefore,the networking technology becomes the key issue in the developing process of visible light communication.By the influence of path loss,the coverage of an access point(LED)is limited,which is between 3 to 5 square meters in a typical indoor network.In order to meet the need of lighting and mobile communication,multi LED access points are deployed in each room.To improve the spectral efficiency,each access point uses the full-frequency strategy,which has a bad influence on the receiving signal of the users in the overlapping areas of adjacent access points.This thesis aims to propose a resource allocation algorithm to address the interference in VLC network and improve the quality of service of the users in overlapping areas,as well as the user fairness and system throughput of the network.After that a software simulation platform is established to verify the proposed algorithm.The main contributions of this thesis are as follows:First,the backward forward marked interference control algorithm is proposed based on bipartite graph.Firstly,according to the characteristics of visible light communication,the network is modeled as a bipartite graph.Furthermore,the backward forward marked algorithm is utilized to mark and erase the edges of the bipartite graph.Finally,the remaining graph show the result of the allocation scheme.This algorithm takes the advantage of the transmission property of visible,as well as the theories of bipartite graph,to decrease the influence of the interference.Meanwhile,the cooperation transmission is utilized to improve the data rate and fairness by converting the interference signal into useful signal.Second,a system-level software simulation platform for visible light communication is designed and established.This platform has a high degree of flexibility and scalability by using high cohesion and loosely coupling.So this software platform can be used in a variety of scenarios.Each module of the platform provides several solutions.Meanwhile,the pros and cons of different solutions have been compared and validated.