中继协同的无线物联能量收集和信息传输算法

本文针对两跳无线物联通信系统，对中继节点利用收集的能量采用功率分流法进行能量收集和信息传输算法进行了设计，其中算法设计是基于能效最大化的优化准则，能效函数定义为瞬时吞吐量与硬件电路总功耗的比值，中继节点利用源节点发送的信号进行能量收集，考虑EARTH计划中实际的功率转换效率和硬件电路损耗的功耗因子，推导了中继协同的无线物联系统能量收集和信息传输的最优功率分配方案的解析解，由于优化问题是非凸问题，为了解决该问题，本文利用高信噪比近似法并通过拉格朗日算法和Lambert W函数获得了优化问题的最优解，数值仿真验证了所提方案的正确性和有效性。 

Energy Harvest and Information Transmission algorithm in Wireless Internet-of-Things with Relay Cooperation

Wireless energy transmission is considered in the Internet-of-Things (IoT) dual-hop communication systems.In this paper, the energy collection and information transmission algorithms of the relay nodes using the collected energy by power shunting method are designed.The algorithms is formulated to maximize the energy efficiency defined as the ratio of the wireless information throughput of the first destination node over the power consumed by the whole IoT systems, which is subject to the required minimum energy harvested at the second destination node of the energy transfer.The relay node uses the signal sent by the source node for energy harvesting.Considering the actual power conversion efficiency and hardware circuit loss power factor in the EARTH plan, the analytical solution of the optimal power allocation scheme for the energy-collecting and information transmission of the wireless coordinated IoT system is derived.To tackle the non-convex problem, the exact expression of the wireless information throughput is approximated by the high signal to noise ratio (SNR) approximation method. Hence, the asymptotically optimal solution is derived in analytical expression by employing the Lagrangian method. Numerical simulations verify the performance of the proposed scheme.