Search

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. [ABSTRACT FROM AUTHOR]

Abstract: This paper studies the error performance of power line communication (PLC) systems, in the presence of background noise with Nakagami‐m distributed envelope and uniformly distributed phase. In this sense, we present closed‐form expressions for the symbol error rate (SER) of PLC systems using binary pulse amplitude modulation and generalize the analysis to accommodate the M‐ary pulse amplitude modulation. In addition, novel closed‐form expressions for the SER upper bound of rectangular quadrature amplitude modulation PLC systems are derived. Interestingly, these expressions can be considered as tight SER approximations in the high–signal‐to‐noise ratio region and, thus, can efficiently evaluate the operational bound of a PLC system. [ABSTRACT FROM AUTHOR]