中文摘要：

设备间通信（D2D通信）通过复用蜂窝通信的频带资源，可以使近距离的用户直接通信，而无需通过基站进行中继。它的引入可以提升用户的服务质量，降低终端能耗，拓展小区的覆盖范围。特别的，在CDN场景中，可通过移动中继向请求相同业务内容的用户进行D2D广播传输。但是，在上述场景中，需考虑到移动终端（MT）的能耗和与蜂窝用户之间的同频干扰问题。基于此，提出了一种基于粒子群优化（PSO）算法的联合中继节点选择和功率控制机制来最小化移动中继的总能耗并同时保证两类用户的服务质量（QoS）需求得到满足。通过仿真，此方案效果得到了验证。

英文摘要：

Device-to-device（D2D） communication enables direct data transmission between mobile terminals （MT） in proximity by reusing the frequency of traditional cellular network. It is capable to improve individual quality of service （QoS）, reduce MT＇s energy consumption and expand cell coverage. Particularly, when multiple MT request the same content of service at cell edge, some MT in their vicinity could relay the data to them by means of D2D muhicast transmission. However, due to the limited battery lifetime of MT and spectral reusing between D2D and cellular communications, relay node selection and power control are two key techniques needed to be addressed. A particle swarm optimization based scheme to minimize the sum power consumption of mobile relays while guarantee the individual QoS requirement by incorporating both relay node selection and power control was proposed. The efficacy of our scheme was extensively verified through numerical results.