Research Article Mobility-Centric Analysis of Communication Offloading for Heterogeneous Internet of Things Devices Dmitry Kozyrev, 1,2 Aleksandr Ometov , 3 Dmitri Moltchanov, 3 Vladimir Rykov, 1,4 Dmitry Efrosinin, 1,2 Tatiana Milovanova, 1 Sergey Andreev, 3 and Yevgeni Koucheryavy 3 1 RUDN University, Moscow, Russia 2 V.A. Trapeznikov Institute of Control Sciences of Russian Academy of Sciences, Moscow, Russia 3 Tampere University of Technology, Tampere, Finland 4 Gubkin Russian State University of Oil and Gas, Moscow, Russia Correspondence should be addressed to Aleksandr Ometov; aleksandr.ometov@tut.f Received 6 April 2018; Revised 30 June 2018; Accepted 12 July 2018; Published 5 August 2018 Academic Editor: Sudarshan Guruacharya Copyright © 2018 Dmitry Kozyrev et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Today, the number of interconnected Internet of Tings (IoT) devices is growing tremendously followed by an increase in the density of cellular base stations. Tis trend has an adverse efect on the power efciency of communication, since each new infrastructure node requires a signifcant amount of energy. Numerous enablers are already in place to ofoad the scarce cellular spectrum, thus allowing utilization of more energy-efcient short-range radio technologies for user content dissemination, such as moving relay stations and network-assisted direct connectivity. In this work, we contribute a new mathematical framework aimed at analyzing the impact of network ofoading on the probabilistic characteristics related to the quality of service and thus helping relieve the energy burden on infrastructure network deployments. 1. Introduction and Motivation Te uncontrollable growth in the numbers of interconnected Internet of Tings (IoT) devices has a tremendously adverse efect on the existing wireless networks [1]. It has been recently shown that there are more than four million base stations (BSs) each consuming an average of 2.3MWh per month [2], and the volume of newly deployed BSs is growing exponentially, especially in the developing counties. Such an extreme energy consumption burden has its infuence on the energy costs, greenhouse efect, and global impact on climate in general [3]. One of the ways to control the increase in the numbers of newly deployed BSs is to efciently utilize the existing system infrastructure [4] by, e.g., attempting to switch between the radio technologies instead of “densifying” the deployment area [5]. Tis paradigm is known as heterogeneous network- ing [6] as part of the next-generation (5G) systems and beyond. However, seamless implementation of this approach is associated with many practical difculties, e.g., when the existing infrastructure is owned by diferent service providers. Another potential enabler of green communication is device-to-device (D2D) connectivity [7, 8]. Tis technique allows reducing power consumption and improving network capacity and throughput by utilizing, e.g., unlicensed wireless spectrum controlled by the operator [9]. Basically, a mobile device equipped with two or more radio interfaces has an opportunity to utilize short-range wireless links to communi- cate with its neighboring nodes by reaching common goals, like data caching, edge computing, coverage extension, etc. [10]. As cellular spectrum remains expensive in terms of capacity and energy, it could be freed with D2D ofoading, thus enabling green communication [11]. In this regime, the cellular network is only responsible for controlling the connection between the user equipment (UE) devices. One more way to improve the communication quality is based on the use of unmanned aerial vehicles (UAVs). Histor- ically, UAVs have already demonstrated their applicability for weather monitoring, forest fre detection, trafc control, etc. Hindawi Wireless Communications and Mobile Computing Volume 2018, Article ID 3761075, 11 pages https://doi.org/10.1155/2018/3761075