Optimization of Ultra-Dense Wireless Powered Networks

Abstract

The internet-of-things (IoT) is expected to have a transformative impact in several different domains, including energy management in smart grids, manufacturing, transportation, smart cities and communities, smart food and farming, and healthcare. To this direction, the maintenance cost of IoT deployments has been identified as one of the main challenges, which is directly related to energy efficiency and autonomy of IoT solutions. In order to increase the energy sustainability of next-generation IoT, wireless power transfer (WPT) emerged as a promising technology; however, its effectiveness is hindered as the distance between the base station and the wireless powered IoT devices increases. To counter this effect, decentralized approaches based on the use of distributed densely deployed remote radio heads (RRHs) can be utilized to diminish the distance between the transmitting and the receiving nodes. A trade-off ensues from the use of RRHs as power beacons (PBs) or access points (APs) that enable either energy transfer during downlink or information reception during uplink, respectively. To balance this trade-off, in this work, the maximization of the ergodic rate in ultra-dense wireless powered networks is investigated. In more detail, three different protocols are introduced, optimized, and compared to each other: density splitting, time splitting, and hybrid time and density splitting, which are based on the optimization of the portion of the number of RRHs that are employed as PBs or APs at a specific time instance. Additionally, two different policies are taken into account regarding the PBs’ power constraint. The formulated problems that correspond to the combination of the proposed protocols with each of the two considered power constraint policies are optimally solved by using convex optimization tools and closed-form solutions are derived that result to useful insights. Finally, numerical results are provided, which illustrate the ergodic rate achieved by each of the proposed protocols and offer interesting conclusions regarding their comparison, which are directly linked to design guidelines and the required capital and operational expenses.

Next Generation Multiple Access: Performance Gains From Uplink MIMO-NOMA

“…Of course, different applications require different buffer sizes and delay requirements, which are both taken into account in this work. Among others, the proper use of buffers is critical in IoT applications, including data collection in smart grids, manufacturing, smart cities and communities, smart food and farming, and healthcare applications [42]. Also, the considered system model could correspond to a scenario in which multiple aerial (e.g., unmanned aerial vehicles) or marine nodes communication with a terrestrial BS.…”

Simultaneous Wireless Information and Power Transfer in Multi-User OFDMA Networks with Physical Secrecy

“…The former can be mitigated by efficient protocols [ 1 , 2 , 3 ]. A solution for the latter is energy harvesting [ 4 ], especially simultaneous wireless information and power transfer (SWIPT) [ 5 ], where receivers harvest energy and decode information simultaneously from the same received signal by a power splitter. This power splitter divides the received signal into two copies.…”

PSON: A Serialization Format for IoT Sensor Networks

“…Some of them aim to optimize energy by designing routing protocols [ 15 , 16 ]. Other work has focused on the development of Wireless Power Transfer (WPT) technology [ 17 , 18 , 19 , 20 , 21 ] or Energy Harvesting (EH) [ 22 ]. However, the focus of this research work is on the efficient transfer of data from devices to the server-side.…”