Research On Resource Allocation In D2D-enabled Heterogeneous Cellular Networks

With the rapid development of Internet technologies and wireless communication technologies,the explosive growth in mobile communication data traffic and access network equipments have proposed higher system capacity and faster transmission rate requirements for next generation of 5G networks.In order to meet the needs of future 5G networks,such as Millimeter Wave,Small Cell,Device-to-Device(D2D)and other new technologies have attracted the extensive attention of many scholars.Therefore,the future 5G networks is likely to be a hybrid network where multiple technologies exist at the same time.This thesis focuses on the resource allocation problem in hierarchical heterogeneous networks composed of macrocell,Small Cell and D2 D communication.The details are as follows:Firstly,this thesis mainly researches cross-layer interference problem caused by D2 D users and Small Cell users who reuse macrocell user's uplink spectrum resources.In order to reduce the cross-layer interference among macro layer,Small Cell layer and D2 D layer in the network,this thesis proposes a resource allocation scheme based on hypergraph.First,execute the reuse license control of D2 D users and small cell users under any subchannel assignment,and establish a cellular user candidate set for D2 D users and small cell users according to QoS requirement and transmit power constraint;Then,D2 D users and small cell users who reuse resources choose the best transmit power.Finally,formulate the channel allocation problem as a hypergraph model,and allocate resources to D2 D users and small cell users based on the branch-and-bound method.The simulation results show that the proposed scheme can improve the throughput of D2 D and small cell users in the system effectively.Secondly,this thesis mainly researches same-layer and cross-layer interference problem caused by D2 D users and small cell users who reuse macrocell user's downlink spectrum resources under Small Cell and D2 D intensive deployment scenarios.In order to reduce the interference in the network and reduce the computational complexity,this thesis proposes a distributed resource allocation algorithm based on the matching theory.First,small cell users and D2 D users are called reuse users,and build a preference list according to utility function.Then,in order to solve the “externality” between matching individuals,all reuse users establish their own conflict sets according to location information.Finally,allocate spectrum resources to small cell users and D2 D users based on a one-to-many matching algorithm with dynamic quotas and conflict sets.The simulation results show that the proposed algorithm can improve the spectrum utilization and total throughput of reuse users effectively,at the same time,the proposed algorithm can reduce the computational complexity.