Channel And Power Allocation Algorithm For Device-to-Device Communication System

D2D communication technology allows adjacent mobile terminals to directly perform point-to-point data transmission.Due to the short distance of the D2 D link,D2 D communication can bring capacity gain,multiplexing gain and power gain,which helps to improve the spectral efficiency and energy efficiency of communication system.On the other hand,D2 D communication also brings a more complicated electromagnetic interference environment to the cellular network.If the interference can not be effectively controlled,D2 D communication can impair the communication quality of other cellular users and thus reduce the overall system performance.Therefore,effective interference management mechanism is the key to exploit the potential advantages of D2 D communication,and is also a difficult point.This thesis studies the channel assignment and power control of cellular users and D2 D users in heterogeneous cellular networks,in order to give full play to the advantages of D2 D communication.The concrete contents are as followed:(1)In order to effectively improve the total rate of D2 D users as well as the fairness between different users,this thesis proposes a utility based fair resource allocation algorithm.The proposed algorithm uses the utility function of which marginal utility decreases and establishes an optimization problem that maximizes the overall utility of D2 D users.Because of the non-convexity of the original mixed integer non-liner programming problem,this thesis first adopts the Lagrangian relaxation method to make it convex.Then,the dual decomposition and sub-gradient methods are used to get the optimal transmit power of D2 D users and assign the channel to them.Simulation results show that the proposed algorithm can achieve a certain compromise between the total rate of D2 D users and system fairness.(2)To better meet the quality of service requirements of D2 D users,the concept of user satisfaction is introduced and a QoS-based clustering channel allocation algorithm is proposed.The proposed algorithm uses graph coloring method to allocate channels for D2 D users and can be divided into three steps.First,an interference graph between D2 D users is constructed.Then,it establishes the available color lists for D2 D users while guaranteeing the QoS requirements of cellular users.Finally,the D2 D users are clustered and only those in the same cluster can share the channel.Simulation results show that the proposed algorithm can effectively improve the system performance in terms of the satisfaction of D2 D users as well as system fairness.(3)For the full duplex cellular communication scenario,a resource allocation algorithm based on graph coloring is proposed aiming at maximizing the throughput of the system.It allocates channels for cellular users and D2 D users in two steps: First,Hungarian algorithm is used to match the uplink cellular users and the downlink cellular users,and a pair of cellular users can enjoy a resource block simultaneously for uplink and downlink communication.Then the channel is allocated to D2 D users based on the graph coloring theory while ensuring the quality of the cellular users.The simulation results show that the algorithm can improve the system throughput and obtain higher spectral efficiency.