In this paper we consider data transmission in a decode-and-forward(DF)relay-assisted network in which the relay is energy harvesting(EH) powered while the base station(BS) is power-grid powered.Our purpose is to maximize the BS's energy efficiency(EE) while making full use of the relay's renewable energy and satisfying the specific average throughput requirements.In contrast to existing literature on energy harvesting system which only considers the radio transmission power,we take the static circuit power into account as well.We formulate the EE optimization problem and prove that the EE of the BS and relay are both quasiconvex in the instantaneous transmission rate.Then we divide the complex optimization problem into two point-to-point link level optimization parts and propose an energyefficient resource allocation(EERA) scheme in which power control and sleep mode management are jointly used.The simulation results demonstrate that EERA may achieve good energy saving effects.We also compare the EE of an energy harvesting relay system with a power-grid powered one and provide more insight into the EE problem of energy harvesting relay system.
为提高模拟网络编码系统的安全传输容量,提出一种基于天线选择物理层安全传输方案;研究在准静态慢衰落信道条件下,源结节与中继结点的天线选择策略及其性能分析。该方案分别以最大信道容量和最大信道增益为目标,在最优选择准则基础上,提出简化的天线选择方法。数值仿真表明:联合主信道容量最大化(CMCCM)准则具有最优的性能曲线,但其运算复杂度也最大。相比于固定选择策略,CMCCM方案提供系统增益约5 d B。特别地,简化的独立信道增益最大化(ICGM)方案与CMCCM方案表现出接近的性能曲线。
