The low power wide area network (LPWAN) technologies, which is now embracing a booming era with the development in the Internet of things (IoT), may offer a brand new solution for current smart grid communications due to their excellent features of low power, long range, and high capacity. The mission-critical smart grid communications require secure and reliable connections between the utilities and the devices with high quality of service (QoS). This is difficult to achieve for unlicensed LPWAN technologies due to the crowded licensefree band. Narrowband IoT (NB-IoT), as a licensed LPWAN technology, is developed based on the existing LTE specifications and facilities. Thus, it is able to provide cellular-level QoS, and henceforth can be viewed as a promising candidate for smart grid communications. In this paper, we introduce NB-IoT to the smart grid and compare it with the existing representative communication technologies in the context of smart grid communications in terms of data rate, latency, and range, etc. The overall requirements of communications in the smart grid from both quantitative and qualitative perspectives are comprehensively investigated and each of them is carefully examined for NBIoT. We further explore the representative applications in the smart grid and analyze the corresponding feasibility of NB-IoT. Moreover, the performance of NB-IoT in typical scenarios of the smart grid communication environments, such as urban and rural areas, is carefully evaluated via Monte Carlo simulations.

INTRODUCTION

T HE Internet of things (IoT), as revealed by its name, denotes the concept that every object is connected and has the capability of sending and receiving data. The key element to enable the IoT paradigm is the seamless integration of potentially any object with the Internet, which creates new forms of interaction between human and devices, as well as among devices themselves, which is commonly referred to as the machine-to-machine (M2M) communications [1]. The IoT, or M2M in particular, scenarios are considered as major challenges for the next generation wireless cellular systems, since most of the IoT services are expected to generate a relatively small amount of traffic and lower power consumption from a very large number of devices, whereas current cellular communication architectures are designed for wideband services aiming for higher data rate and spectral efficiency [2]. Thus, the shift of paradigm urgently calls for a new breed of wireless technologies to consummate the 5th generation mobile networks (5G) [3]. Recently, a new wireless technology called low power wide area network (LPWAN), due to its long-range, low-power, and low-cost communication capability, has gained unprecedented momentum and commercial interest from both the academia and the industry [4]. It is now widely considered as the future wireless communication standard for IoT. LPWAN technologies can perfectly serve most IoT applications with the abilities to offer a large scale of coverage and a massive capacity of supporting millions of devices per cell, as well as long battery life of up to 10 years. Cisco estimates that the market of LPWAN is expected to account for 28% of M2M connections by 2020 with a 38% compound annual growth [5]. The breed of LPWAN technologies can be divided into two categories according to their operating frequency bands. One set of LPWAN technologies operates on the unlicensed industrial, scientific and medical (ISM) radio bands, such as LoRa (Long Range) [6] and Sigfox [7]. The other set operates on the licensed bands, such as enhanced machine type communications (eMTC) and narrowband IoT (NB-IoT) [8].