D2D通信系统中的最优中继选择及功率分配策略研究

在D2D(device-to-device)通信系统与蜂窝网络共存的场景下,引入中继节点可以有效提高D2D链路的吞吐量同时减小D2D链路对蜂窝网络的干扰?阐述了一种新颖的半双工放大转发双向中继协助D2D通信方案,提出了对应的最优中继选择及功率分配算法?该算法能够在满足蜂窝系统所受干扰小于一定门限值的约束下最大化D2D链路的吞吐量?该算法优化了D2D链路上各发送节点的发送功率;选出了可以使D2D链路吞吐量最大化的中继节点作为最优中继节点?其中,在计算最优功率分配的时候,利用拉格朗日对偶理论以及最速下降法对原功率分配优化问题的对偶问题进行了分层迭代求解?仿真结果表明,提出的策略与已有的方案相比可以显著提高D2D链路的吞吐量?

Optimal relay selection and power allocation method for device-to-device communication systems

In the scene of device-to-device(D2D)communication underlay the cellular network,relay assisted transmission could efficiently improve the throughput of D2D communication system while minimizing the interference from D2D link to the cellular network. Therefore,a novel scheme of a half duplex amplify and forward two-way relay to assist D2D users communication is proposed,and an optimal relay selection and power allocation algorithm is presented.The proposed algorithm can maximize the throughput of D2D link while ensuring the interference power for the cellular network under a threshold.Two steps are needed to realize the proposed algorithm:First,the optimal transmit power of the D2D link is obtained;Second,the optimal relay node that can maximize the D2D link''s throughput is chosen.Particularly,in the first step,Lagrangian duality theory and the steepest descent method are adopted to obtain the optimal solution of the originalproblem. Finally,simulation results verify that compared with existing schemes,the proposed algorithm can significantly improve the throughput of D2D links.