Our era is characterized by the rapid proliferation of Internet-connected devices, which enables the digital transformation of physical processes as part of the Internet of Things (IoT) paradigm. High speed and resilient network connectivity is a key prerequisite for any non-trivial IoT deployment since it provides the means for collecting data streams from IoT devices. In order to meet this requirement, IoT applications rely on mainstream network connectivity technologies (e.g., WiFi, 3G, 4G / LTE (Long Term Evolution)) in order to transfer IoT data from the physical world to the edge and cloud systems that comprise an IoT deployment.
Nevertheless, these networking technologies were not designed and developed with the IoT paradigm in mind. Hence, they make no special provisions for the connectivity of IoT devices i.e. they do not consider the nature and characteristics of IoT traffic. For example, they do not cater for energy efficient communications with devices, which are particularly important for Industrial IoT applications. Likewise, they are not designed to support the flexible deployment and management of large numbers of devices, which is a common requirement in IoT and Machine-to-Machine (M2M) applications.
During the last few years, a new wave of connectivity technologies has emerged, which includes technologies tailored to the requirements of IoT deployments. These technologies are characterized as Low Power Wider Area Networks (LPWAN) technologies and are constantly gaining momentum as part of both public and private IoT infrastructures.
LPWAN Properties
The main characteristic of LPWAN technologies is the fact that they require relatively low-bandwidth connectivity, which allows them to operate in long ranges and in a power efficient way. In principle, LPWAN technologies support bi-directional data transmission and cover larger areas, typically larger than conventional wireless and mobile networks. However, they support quite low data transfer rates as they are tailored to devices that operate with low bandwidth requirements. Moreover, they operate in a power efficient way, which is very important for several IoT applications, such as applications in manufacturing shop floors, energy plants, and smart cities. Overall, LPWAN technologies are tailored to the connectivity and networking needs of IoT and M2M applications, as their low power and long-range support properties make them more suitable for device saturated environments than conventional WiFi and 3G/4G technologies.
During the last couple of years, we are witnessing a proliferation of LPWAN deployments in various urban and industrial environments worldwide. LPWAN deployers aim at the following benefits:
- Cost-Effective Deployments: LPWAN infrastructures are installed at a low effort and cost, especially when battery-operated devices are used. The battery-operated devices can be energy autonomous for several years and hence no power source is required. Moreover, LPWAN infrastructures provide very good indoor coverage, which facilitates in-door deployments within a range of several kilometers from the LPWAN base equipment. Also, LPWAN deployers need not perform complex coverage analysis studies, which saves consulting costs. Furthermore, there are LPWAN technologies that can be deployed in the ISM (Industrial, Scientific, and Medical) band, which is provided at zero spectrum cost. Finally, there is healthy competition in the LPWAN market due to the existence of different technologies and service providers, who keep prices within reasonable margins.
- Ecosystem Support: The most popular LPWAN technologies (e.g., LoRaWAN, NB-IoT, and SigFox) are currently associated with large ecosystem of developers, deployers, users and service providers. LPWAN ecosystems are sources of solutions and technical support, which makes the life of service providers and deployers easier.
- Strong Security: LPWAN equipment (e.g., gateways) support strong security features such as authentication, authorization, and encryption, which safeguards IoT applications from major cyber-threats.
- Geolocation Support: LPWAN technologies provide excellent support to geolocation applications. In particular, they provide location-awareness functionalities without a need for additional power sources, while at the same time provide indoor coverage capabilities i.e. indoor geolocation features.
LPWAN Technologies
The term “LPWAN” denotes a pool of different technologies with the above-listed characteristics and advantages. The most popular LPWAN technologies are:
- LoRaWAN™ is an LPWAN technology that is specified and promoted by the LoRa Alliance™. For this reason, it is conveniently called LoRaWAN. It supports connectivity of wireless battery-enabled devices and operates in various geographical scopes (i.e. regional, national and global). LoRaWAN provides deployment flexibility and cost-effectiveness since it is very easy to install in both indoor and outdoor environments. A LoRaWAN deployment consists of gateways that transfer relay messages between connected devices, a back-end server, as well as various end devices (e.g., sensors, smart meters) that connect to the gateways using various frequency channels and adaptive data rates. LoRaWAN is an open specification, which is supported by hundreds of members of the alliance, including vendors, network operators, and IoT start-ups. These organizations are part of the LoRaWAN growing ecosystem, which actively supports the development and deployment of LoRaWAN infrastructures and applications.
- SigFox / Ultra Narrow Band (UNB) technology operates over very narrow spectrum channels, (i.e. typically <1KHz) to achieve ultra-long distance linking of transmitters and receivers. UNB technology is used by SigFox, which is one of the world’s most popular LPWAN deployers. This is the reason why UNB technology is conveniently called SigFox. UNB requires sophisticated base stations, which demodulate UNB signals across the full 192 kHz spectrum. SigFox is developing a global network outside the licensed spectrum based on a close collaboration with many enterprises worldwide.
- Haystack is based on the DASH7 standard. This standard enables long range, low power wireless communications for applications with low bandwidth requirements such as transmission of text messages and sensor readings. It is an open source protocol, which operates primarily in sub-1GHz frequency bands, usually between 315 MHz and 915 MHz. Haystack/DASH7 is nowadays one of the simplest to deploy LPWAN solutions.
- NarrowBand IoT (NB-IoT) relies on cellular spectrum bands in order to provide connectivity to IoT devices. NB-IoT is a narrowband radio technology that is based on LTE radio specifications. Hence it is backward compatible with legacy broadband LTE systems. It offers very good and cost-effective indoor coverage, as well as power efficient operations for the devices that connect to it.
- Wi-Fi HaLow is WBA’s (Wireless Broadband Alliance) LPWAN proposal. It operates in the 1GHz ISM band and is based on the IEEE 802.11ah protocol. HaLow provides longer range and lower power operation than other WiFi technologies, yet it offers lower throughput. Hence, it is WBA’s preferred solution for large-scale IoT devices’ deployments.
LPWAN systems are already widely deployed and are currently supporting many IoT applications, including mission-critical and security sensitive ones. They also offer location-aware functionalities in smart environments, which enables many value-added applications in areas such as asset management, security, surveillance, safety and supply chain management. The market momentum of LPWAN technologies reveals that they are here to stay. Nevertheless, we don’t expect them to eliminate the use of legacy IoT connectivity technologies such as 3G/4G and satellite technologies. The latter technologies will rather co-exist with LPWAN in various deployment configurations. LPWAN technologies are here to boost IoT adoption, without disrupting the evolution of mobile/wireless technologies towards their fifth generation (5G).
