| With the development of mobile wireless communication technology,mobile user devices grow explosively and users’ data demand increases exponentially.The Fifth Generation Mobile Communication(5G)has become a hot topic.As one of the key technologies of 5G,ultra-dense network(UDN)has attracted the attention of researchers because it can provide very high data rate and has prosperous deployment prospect.UDN can significantly improve system throughput,but it also brings a series of problems such as access selection,resource allocation,interference management and mobility management.Due to the dense deployment of the access points(APs)in UDN,a user can connect to multiple APs at the same time.How to allocate resources between APs and make them cooperate better to provide services to users is a key issue.In addition,UDN simulation platform is an important method to further study the networking key technologies and relative algorithms in UDN.At present,there is no universally recognized UDN simulation platform,and then it requires systematic design and construction.In view of the above problems,this paper studies the resource allocation algorithm and the simulation platform construction of ultra-dense network.In this paper,a service-driven resource allocation algorithm based on system energy efficiency is proposed in the user-centric ultra-dense network.A unique access point group(APG)is established for a user to provide services when the user accesses the network.Then the sub-carriers and power are allocated within the APG considering the channel condition,user demand and location.When the user’s demand changes,the member of APG and the corresponding resource allocation will be dynamically adjusted.This problem is modeled as a mixed integer nonlinear programming problem,and an efficient multiple tabu search algorithm is adopted to solve it.Simulation results show that the proposed algorithm can effectively improve the energy efficiency of the system and get higher user data rate than existing algorithm.This thesis uses open source OMNeT++(Objective Modular Network TestBed in C++)to build an UDN simulation platform.There is no existing UDN network project in OMNeT++,and the relevant communication protocols of 5 G are in standardized discussion.Therefore,the proposed UDN simulation platform considers the open source SimuLTE project as reference.Because there are many differences between UDN and LTE in node functions,network architecture and performance,the work needs thorough research and construction.The main contributions of the proposed UDN simulation platform include the design and realization of user node and base station node,the research and realization of functions modules such as signal broadcast,access control and handover,and the building of relevant function modules as topology simplification,resource block configuration and multiple-input multiple-output(MIMO)technology.The typical communication process is also designed and simulated.Furthermore,in order to simulate the communication environment of UDN and support the computation of received signal strength,channel models of Manhattan city scene,pedestrian street scene and open-air scene are constructed in this platform.To simulate the users’ mobility pattern in typical scenes,mobility models of Manhattan city scene and pedestrian street scene are realized.On the basis of the above work,the typical simulation scenarios of Manhattan city scene and pedestrian street scene are set up respectively.Then the end-to-end delay and throughput are evaluated and analyzed as the output of this platform. |
