Research On Resource Allocation In LTE And Device-to-device Communication Network And NS3 Simulation Platform

With the development of smart devices and mobile applications,mobile communication services need higher speed,more capacity and better quality of service.Long Term Evolution(LTE)network is struggling to accommodate the mobile users' booming data demand.Device-to-Device(D2D)communication technology can bring significant performance improvement on system throughput and spectrum efficiency by allowing direct communications between users.Hence D2D communication has a wide research prospect.With D2D communication underlaying LTE cellular networks,the hybrid network will have advantanges of them both.On one hand,D2D communication can offload for cellular base station and improve network capacity.On the other hand,it can reduce the transmitting power of terminals and save system energy consumptionHowever,many mobile services such as video data flow and interactive game are delay sensitive.So delay guaranteed resource allocation scheme in LTE and D2D hybrid communication network is needed to support users'demand on quality of services.In this paper,a delay guaranteed resource allocation scheme is proposed and the performance of the scheme is verified.What's more,a LTE system-level simulation platform based on Network Simulator 3(NS3)is constructed.In order to get better simulation result of mobility management in LTE system,mobility management module is modified to support S1 interface based handover.The main work is summarized below:1.Outline the way of constructing LTE and D2D hybrid communication network.Then the main research directions and existing technologies of radio resource management in hybrid communication network are concluded.According to the optimization objective,different kinds of resource allocation algorithms are classified.2.Delay guaranteed resource allocation scheme in cellular and D2D hybrid communication network is proposed.At first the condition of resource blocks allocation and the constraints of power and delay are introduced.Then the resource allocation problem is transformed into a mixed integer non-linear programming problem with the objective of maximizing the system throughput.After that the standard particle swarm optimization algorithm is used to solve the problem and design resource allocation scheme.The discrete resource block allocation solution is map to the position of particle in continuous domain.The delay constraint is represented by penalty function.We define the fitness function to evaluate the solutions of particle swarm optimization.At last,the performance of proposed scheme,traverse scheme and random scheme are compared through numerical simulation results.3.LTE system-level simulation platform is built based on NS3.Then it is improved on the basis of the original function.The mobility management module is modified to support more than one mobility management entity.Furthermore,S1 interface based handover procedure is added through the improvement of many network entities in access network and core network.So the simulation of mobility management is more accuracy.