Abstract: Device-to-device ( D2D) communication underlaying LTE-A cellular networks can increase the utiliza- tion efficiency of cellular resources effectively.However,the co-channel interference caused by cellular resources reuse may degrade the system throughput.An effective power control scheme can effectively suppress the interfer- ence and improve the overall performance.In order to further improve the power efficiency of cellular users,a pow- er control scheme on the basis of power efficiency optimization is presented.Firstly,according to the characteristics of network resources reuse,power efficiency is redefined from the viewpoint of resource usage.Then,power alloca- tion is formulated with the objective of maximizing power efficiency,and a step length-variable incremental iteration algorithm is proposed to derive the optimal power for both cellular and D2D users.Simulation results indicate that the proposed power control scheme helps obtain higher throughput with lower power consumption,outperforms the existing scheme by approximately 15% increment in power efficiency,decreases the computational complexity,and reduces the impact of mutual interference effectively.

Key words: device-to-device communication, power control, power efficiency, step length-variable incremental it- eration