Resource Allocation For D2D Communication Underlaying Cellular Networks

As one of the key technologies of 5G mobile communication,device-to-device(D2D)technology allows two or more devices in close proximity communicate directly without the intervention of a base station.It can significantly improve the network spectral efficiency and energy efficiency,alleviate the problem of spectrum scarcity and limited battery capacity.Introducing D2 D technology into cellular network can improve the system performance,but it will lead to complex co-channel interference into the network.How to mitigate the interference and further improve the energy efficiency of D2 D network has attracted more attention.From the perspective of physical layer security,co-channel interference may become beneficial,as D2 D user equipments(DUE)can act as friendly jammers and help cellular user equipment(CUE)prevent to be wiretapped.However,security performance mainly depends on the selected jammers and their transmit power,which deserves further study.In order to solve these problems,great deals of research works have been done in this thesis.On one hand,a D2D-enabled cellular network where D2 D users can share the same spectrum resources with cellular users is established.To maximize the energy efficiency of D2 D system with spectral efficiency constraint,we propose a novel radio resource allocation algorithm.Firstly,D2 D users are clustered based on the interference graph method;secondly,the non-convex optimization problem with fractional form is equivalently transformed into an optimization problem with subtractive form by nonlinear fractional programming method;finally,a joint resource allocation and power control iterative algorithm is proposed to solve this problem.Simulation results show that the proposed scheme can greatly improve the energy efficiency,and this algorithm is proved to have a good convergence.On the other hand,we provide a jointly optimal resource sharing strategy which can not only improve the security rate of CUE but also increase the sum transmission rates of D2 D links.In order to maximize the security rate of CUE who has priority to get spectrum resource,we put forward a secrecy-based access control scheme with the best D2 D pairs selection mechanism.To ensure the fairness between DUE and CUE in cooperation,we further derive an optimal power control strategy to maximize the sum transmission rate of the selected D2 D links.Simulation results show that the security rate of CUE and the sum transmission rate of DUE can be effectively increased when DUE are considered as friendly jammers.