Implementation of relay hopper model for reliable communication of IoT devices in LTE environment through D2D link

Internet of things (IoT) is an emerging technology that can bring about a revolution in our day-to-day lives. Device-to-device (D2D) communication is an energy and spectral efficient solution to the growing problem of scarcity of free spectrum and overloading of base stations in cellular networks. The concept of using D2D communication in IoT networks has already been proposed. But the reliability of the links established by reusing the resource blocks allocated to licensed cellular users has not been investigated earlier. In this paper, our objective is to provide connectivity between IoT devices and the associated gateway using D2D communication ensuring that links established are reliable, and at the same time improve performance by providing connectivity to the maximum number of IoT devices. We propose a three step approach to achieve this. In the first step, the IoT devices satisfying the Quality of Service (QoS) constraint are selected and matched with appropriate reuse candidates, that is, the cellular user equipments (CUEs) by an optimum resource allocation scheme. Next, link reliability of these links are computed and weak links are discarded. Finally, the disconnected IoT devices are rerouted to the IoT gateway via IoT devices possessing strong links following a relay hopper model. Simulation results indicate significant improvement in the network performance metrics, namely, access rate and sum throughput of IoT devices.