An On-Demand Energy Requesting Scheme for Wireless Energy Harvesting Powered IoT Networks

ABSTRACT

Energy harvesting (EH) delivers a unique technique for replenishing batteries in Internet of Things (IoT) devices. Equipped with an energy harvesting accessory, EH-enabled sensor nodes/IoT devices extract energy from ambient resources such as solar or radio frequency (RF) signals. Relying on residual battery or/and harvested energy, sensor nodes in an IoT network perform data exchange activities. Otherwise, the delivery of sensed data would be delayed until sufficient energy is harvested. In this paper, we propose an on-demand energy requesting (OER)mechanism for improving the delay performance of a wireless EH-powered IoT network. The proposed scheme acquires energy when necessary from an energy transmitter that is capable of transmitting energy via directed RF signals. Furthermore we develop two associated discrete time Markov chain (DTMC)models to analyze the performance of the OER scheme, targeting at a generic synchronous medium access control (MAC) protocol. Using the proposed DTMC models, we evaluate OER with respect to average packet delay, network throughput, packet loss probability, and packet reliability ratio by employing a specific synchronous MAC protocol. Numerical results obtained from both analysis and discrete-event simulations coincide with eacho ther , indicating the accuracy of the models and revealing the behavior of EH based packet transmissions.

EXISTING SYSTEM :

The upcoming 5G networks are capable of interconnecting heterogeneous wireless and mobile systems as well as facilitating Internet of things (IoT) services and device-to-device communication. The IoT connects massive machine-type devices and networked things or objects, making them intelligent through data collection, data exchange, and information analysis. The envisaged IoT applications include smart cities and smart homes, smart grid, industrial automation, and environmental surveillance. Essentially, energy is a scare resource of paramount importance as much longer operation lifetime is expected in next generation wireless sensor networks (WSNs) and IoT networks. In traditional WSNs, the battery supplied to a sensor node has fixed capacity, resulting in a constraint node lifetime. Moreover, problems such as energy hole , which occurs  further shorten network lifetime. To this end, existing energy conservation mechanisms, e.g., duty cycling, and energy balancing techniques like cooperative transmission  could prolong network lifetime. Moreover, mechanisms such as aggregated packet transmission  and event-triggered sleeping  which are designed for duty cycled (DC) WSNs could further extend network lifetime. However, the aforementioned techniques do not provide abundant lifetimes to IoT devices without replacing batteries. On the other hand, energy harvesting (EH)  enables sensor nodes to accumulate energy from surrounding resources. Energy may be harvested from various types of sources such as solar and electromagnetic fields . Through EH, batteries are recharged with the harvested external energy. Accordingly, integrating EH capacity with IoT networks empowers sensor devices to derive energy from renewable energy resources. Ideally energy is interminable in EH-enabled WSNs, but it can be harvested intermittently. Consequently, EH imposes many design challenges for IoT networks.

Energy harvesting (EH) delivers a unique technique for replenishing batteries in Internet of Things (IoT) devices. Equipped with an energy harvesting accessory, EH-enabled sensor nodes/IoT devices extract energy from ambient resources such as solar or radio frequency (RF) signals. Relying on residual battery or/and harvested energy, sensor nodes in an IoT network perform data exchange activities. Otherwise, the delivery of sensed data would be delayed until sufficient energy is harvested.

 PROPOSED SYSTEM :

In this paper, we propose an on-demand energy requesting (OER)mechanism for improving the delay performance of a wireless EH-powered IoT network. The proposed scheme acquires energy when necessary from an energy transmitter that is capable of transmitting energy via directed RF signals. Furthermore we develop two associated discrete time Markov chain (DTMC)models to analyze the performance of the OER scheme, targeting at a generic synchronous medium access control (MAC) protocol. Using the proposed DTMC models, we evaluate OER with respect to average packet delay, network throughput, packet loss probability, and packet reliability ratio by employing a specific synchronous MAC protocol.

CONCLUSION :

In this paper, we proposed an on-demand energy requesting (OER) scheme for wireless energy harvesting based IoT networks. To evaluate the performance of such a scheme, a modeling framework consisting of two sets of DTMCs is developed, representing both the energy harvesting and queuing behavior of the studied network. Based on the successful transmission probability obtained from the developed models, average packet delay, node and network throughput, packet loss, and packet reliability ratio were calculated. Using the numerical results obtained from both analysis and simulations, we demonstrate the supremacy of the proposed OER scheme with respect to all studied parameters, especially under low traffic or low energy harvesting conditions.