Simultaneous Wireless Information and Power Transfer (SWIPT) is an emerging field to transmit information and power in IoT network through the same RF signal. Time switching (TS) protocol is more favorable in free space communication than Power Splitting (PS) protocol when the transmitted RF signal is already weak. This is because, transmitted signal loses its power due to attenuation in free space, and using PS design receiver circuit (complex), the received weak signal is further split into two fraction for energy harvesting (EH) and information decoding (ID) simultaneously, that causes inadequacy in SWIPT system. Whereas, using TS design receiver circuit (simple) insert extra delay in the network as EH and ID operations are done in two different time domain one by one. Literature on SWIPT lacks towards cooperation between more energy harvesting in case of free space communication (TS) and critical information transmission in case of delay constraint communication (PS). In this context, this paper presents a time-slotted SWIPT (T-SWIPT) focusing on maximization of energy efficiency in the relay based sensors-enabled IoT network. It enables simultaneous energy harvesting at receiver and neighboring sensors without adding extra delay in the network. The PS ratio, transmission power allotment and energy broadcast time are jointly formulated as non-convex energy efficiency maximization problem. A solution to the problem is presented using Lagrangian dual decomposition and fractional programming. The performance evaluation shows that T-SWIPT attains optimum energy efficiency by trading off transmission power allotment, power-splitting ratio and sink broadcast time slot.

同时无线信息和功率传输（SWIPT）是一个新兴领域，可通过相同的RF信号在IoT网络中传输信息和功率。当传输的RF信号已经很弱时，时间交换（TS）协议在自由空间通信中比功率分配（PS）协议更有利。这是因为，发射信号由于自由空间中的衰减而失去了功率，并且使用PS设计的接收器电路（复杂），将接收到的弱信号进一步分为两个部分，以便同时进行能量收集（EH）和信息解码（ID），导致SWIPT系统的功能不足。而使用TS设计的接收器电路（简单）会在网络中插入额外的延迟，因为EH和ID操作是在两个不同的时域中一个接一个地完成的。关于SWIPT的文献缺乏在自由空间通信（TS）情况下更多的能量收集与延迟约束通信（PS）情况下的关键信息传输之间的合作。在这种情况下，本文提出了一个时隙SWIPT（T-SWIPT），重点关注基于中继的基于传感器的IoT网络中的能量效率最大化。它可以在接收器和邻近传感器处同时收集能量，而不会增加网络的额外延迟。PS比率，传输功率分配和能量广播时间被共同表述为非凸能效最大化问题。使用拉格朗日对偶分解和分数规划提出了该问题的解决方案。