Modeling and Analysis of Energy Harvesting and Smart Grid-Powered Wireless Communication Networks: A Contemporary Survey

The advancements in smart power grid and the advocation of “green communications” have inspired the wireless communication networks to harness energy from ambient environments and operate in an energy-efficient manner for economic and ecological benefits. This article presents a contemporary review of recent breakthroughs on the utilization, redistribution, trading and planning of energy harvested in future wireless networks interoperating with smart grids. This article starts with classical models of renewable energy harvesting technologies. We embark on constrained operation and optimization of different energy harvesting wireless systems, such as point-to-point, multipoint-to-point, multipoint-to-multipoint, multi-hop, and multi-cell systems. We also review wireless power and information transfer technologies which provide a special implementation of energy harvesting wireless communications. A significant part of the article is devoted to the redistribution of redundant (unused) energy harvested within cellular networks, the energy planning under dynamic pricing when smart grids are in place, and two-way energy trading between cellular networks and smart grids. Applications of different optimization tools, such as convex optimization, Lagrangian dual-based method, subgradient method, and Lyapunov-based online optimization, are compared. This article also collates the potential applications of energy harvesting techniques in emerging (or upcoming) 5G/B5G communication systems. It is revealed that an effective redistribution and two-way trading of energy can significantly reduce the electricity bills of wireless service providers and decrease the consumption of brown energy. A list of interesting research directions are provided, requiring further investigation.

I. Introduction

Future mobile cellular communication networks are envisaged to be rolled out with a dramatically increasing number of cells and continuously reducing cell size, due to explosive mobile traffic [1]. The traffic volume in the emerging fifth-generation (5G) systems and future systems beyond 5G (B5G) is estimated to be tens of Exabytes per month, expecting the capacity of 5G/B5G networks to be 1000 times higher than that of current cellular networks [2], [3]. The thousand-fold increase of system capacity must be achieved with a similar or even lower power level than today’s [4], [5]. Increasing the network energy efficiency (EE) has been pursued by the GreenTouch consortium [6], [7]. Huawei has also deployed solar-powered base stations (BSs) in Bangladesh [8]. Ericson and Nokia Siemens Networks have designed green BSs with renewable power supplies, such as wind turbines and solar panels, to reduce the consumption of fuel generated electricity [9], [10]. Energy-efficient techniques, such as BS switching [11], offline power allocation [12], and online data scheduling [13], [14] have been developed to reduce power consumption or increase network capacity.