Resource Allocation In Ultra Dense Network With CoMP

Ultra Dense Network is considered to be of great importance for its novel network structure in the fifth Generation Mobile Networks.The network throughput and Quality of Service of users can be efficiently improved by deploying denser base station nodes which will take full advantage of space,frequency and time resources of the system.Nevertheless,users suffer larger interference than ever due to small distances between different nodes as well as the network heterogeneity.Thus the advantage of UDN cannot be exploited.Coordinated Multiple Points(CoMP)is one method to implement the interference management.The main idea of CoMP is to avoid the interference or convert the interference signals into useful signals through cooperation among base stations which will improve the Signal to Interference plus Noise Ratio(SINR)of users.However,the implement of CoMP in UDN still confronts with many challenges:(1)The association between users and base stations is one factor influencing the SINR.How to improve the performance of the system by user association is one problem to be solved.(2)Since one user may be associated with multiple base stations,the backhaul load pressure of the network will increase.(3)The resource allocation is more complicated because the Resource Blocks(RB)of base stations need to be cooperatively transmitted.It is essential to design an effective algorithm of RB allocation to meet the requirements of the system resource configuration.In view of these problems,main research content and innovation points of this paper are as follows:This paper investigates caching resource allocation under pre-caching technology to alleviate the heavy load of backhaul link in UDN.Then a caching resource allocation algorithm based on Cross Entropy is proposed to optimize the backhaul load and time delay.The simulation results show that the algorithm can reduce backhaul load and time delay with different caching capacity of small base stations,popularity distribution and the number of users compared to other algorithms.After the configuration of caching resource allocation,this paper studies the user association algorithms.Taking advantage of CoMP,a Load-aware Binary Genetic Algorithm is proposed to solve the problem of user association under the assumption of resource allocation evenly.The simulation results show that the algorithm can improve throughput of cell edge users efficiently and reduce backhaul load.At the same time,fairness of base station's load and fairness of user's sum rate can be improved.As for resource allocation,specific resource blocks allocation algorithm is conducted with the result of user association in the last chapter.Considering the demand of CoMP,this paper proposes an algorithm which is called Resource Balancing-oriented Resource Block Allocated Algorithm.By the simulation results,it is proved to improve throughput of cell edge users and the sum rate of the minimum user further.