Low-power wide area network (LPWAN) is a wireless WAN technology that interconnects low-bandwidth, battery-powered devices with low bit rates over long ranges. LPWAN technology has emerged as an alternative to cellular networks as it provides cost-effective wide area connectivity for internet of things (IoT). It offers several benefits such as low power consumption (operates on small, inexpensive batteries lasting up to 10 years) and suitability for long operating range (of more than 2 km radius in urban settings). Additionally, LPWAN has unique characteristics that make it suitable for deployments across the utilities, logistics and transportation, agriculture and smart cities sectors.
Currently, LPWAN is in its nascent stage and has not yet been deployed widely across the globe. It is still considered as the technology for the future. According to industry reports, the global LPWAN market is expected to grow at a compound annual growth rate (CAGR) of 50.29 per cent during the period 2017-21.
Emerging LPWAN technologies and adoption
- Sigfox, developed by France-based start-up Sigfox in 2010, uses a slow modulation rate to achieve a longer range. Its design makes it an ideal choice for applications where the system requires only small amounts of data. This LPWAN type can be used in parking sensors, smart garbage bins, etc. It is currently being implemented worldwide by network operators.
- LoRa is mainly used for uplink-only applications with many end points. It spreads out information on different frequency channels and data rates using coded messages. LoRa was first developed by a start-up called Cycleo in 2009, which was later acquired by US-based Semtech. In 2015, LoRa was standardised by LoRa-Alliance and is now being deployed in over 42 countries by various mobile operators.
LoRaWAN is the open standard networking layer governed by LoRa Alliance, which has around 400 member companies from North America, Europe, Africa and Asia. In terms of usage, LoRaWAN has found widespread acceptance among telecom companies and smart service providers. LoRa networks have a strong presence in European countries like Netherlands, France and Belgium and it is gradually entering into Germany, Czech Republic, Italy and Denmark. Meanwhile, Comcast is expanding MachineQ, its LoRaWAN IoT service, to 12 US markets. It hopes to implement the technology in areas such as healthcare, public utilities, automotive and smart cities.
In India, Tata Communications has joined hands with Hewlett Packard enterprise (HPE) to create the largest LoRa network in the world by end-2019. The project involves connecting devices, applications and other IoT solutions over the LoRa network in smart buildings, campuses, utilities, fleet management, and security and healthcare services in nearly 2,000 communities, covering over 400 million people.
- Apart from Sigfox and LoRa, Weightless has also been adopted by some countries. This LPWAN technology is the only open standard that operates in sub-1 GHz unlicensed spectrum. There are three versions of Weightless, namely Weightless W, N and P, out of which Weightless N and P are more popular. Weightless N is similar to Sigfox in terms of functionality and claims to use advanced demodulation techniques to allow its network to coexist with other radio technologies without additional noise. On the other hand, Weightless P can be used for private networks in which controlling uplink data and downlink data is important. Weightless N was first launched in Copenhagen, Denmark, followed by London for network deployment under the smart city project.
A key challenge is lack of scalability of LPWAN technologies in dense networks. The performance of LoRa falls significantly as the number of end devices increases. Further, most LPWANs are limited to star topology (in contrast, the cellular-based ones rely on wired infrastructure for integrating multiple networks to cover larger areas). Therefore, lack of proper infrastructure and connectivity hinders their application in rural areas. The existing LPWAN technologies are not designed to handle mobility. Another challenge is the support requirement for control applications, which rely on reliable bi-directional communications. Most LPWANs support uplink-only communication. However, LoRa can enable bi-directional communication, but it has to rely on time synchronised schedules. The most important challenge is security. Most LPWAN technologies support a cryptography method where the device and the network share a secret key. Finally, the rise of cellular IoT technologies like Long-term Evolution Cat M and Narrowband IoT can be a threat to the emerging LPWAN technologies.
Future prospects and opportunities
Once commercialised, LPWAN could accomplish the goal of establishing smart cities around the world. LPWAN can utilise sensors, networking capability and processors fixed in vehicles to improve the driving experience in several ways. It can also assist farmers for better measurement of soil nutrients, fertilisers used, seeds planted, soil water and the temperature of stored produce. LPWAN can also find use in healthcare as it can meet the main requirements of non-invasive sensing, and of secure and reliable communication. Moreover, it is seen as a cheaper alternative to cellular technologies in healthcare applications.