Research On Interference Coordination Management Technology For Ultra-Dense Networks

Driven by the popularity of smart devices,wireless traffic has grown exponentially in recent years.Research has predicted that wireless traffic will increase by 1000 times in 2020 compared to 2010.In general,future networks can achieve capacity growth,in three ways:bandwidth expansion,spectrum efficiency improvement,and network densification.Among them,network intensification is the most important contributor to capacity enhancement in mobile communication systems.Therefore,5G networks adopt the concept of small cells,and deploy low-power small base stations with extremely high density under the coverage of macro base stations to form ultra-dense networks.However,the introduction of the ultra-dense networking method makes the network architecture and service scenarios more complex,and the heterogeneity and densification of the network leads to the most serious interference problem.In order to avoid strong interference in ultra-dense networks,this paper considers two different scenarios in ultra-dense networks,and from the perspective of frequency reuse,combined with the coloring clustering algorithm of graph theory,respectively introduces a incomplete coloring algorithm to achieve clustering of small base stations,and a user-oriented dynamic coloring algorithm to achieve clustering of users.Finally,the effectiveness of the two schemes is verified by simulation.The main research contents of this paper are as follows:Firstly,an interference coordination scheme based on incomplete coloring is proposed.The scheme considers a special scenario in which the number of users is the same as that of the small base stations,and the main purpose is to increase the average user capacity.Firstly,based on the strong interference threshold between the small base stations and the feedback of each small base station,an undirected interference graph with the small base station as the vertex is established.Secondly,according to the coloring algorithm in the graph theory,the incomplete coloring algorithm based on the communication state of each small base station is introduced to cluster the small base stations randomly deployed in the network.Finally,subchannels are allocated dynamically according to the load of each small base station.The simulation results show that the scheme brings a higher average user capacity to the network compared to the interference coordination scheme based on traditional coloring.Secondly,a dynamic coloring interference coordination scheme for users is proposed.This scheme considers the general scenario that the number of users is larger than the number of small base stations.The main purpose is to improve user fairness and improve system throughput and spectrum efficiency.The algorithm first constructs an undirected interference graph with the user as the apex according to the interference threshold and the feedback of the user.Then,the saturation coloring algorithm is used to perfonn dynamic clustering on the vertexes in the established interference graph.Users in the same cluster can reuse the same frequency band because there is no interference between them.Finally,the spectrum resources are allocated to the clusters,which then individually allocate the resource blocks to users within the same cluster.The simulation results show that the user-oriented dynamic coloring interference coordination scheme can improve the average throughput and spectrum efficiency of the system,and the introduction of the user-oriented method improves the network fairness.