In the age of connected devices and the Internet of Things (IoT), more and more research and development is beginning to be focussed on the underlying architectures supporting the Internet of Things and its expansion. At present, there is much competition between competing technologies, all vying for supremacy as the main supporter of the IoT and its growth. Two of the most talked about technologies are LTE-M and LoRa. The battle between these two technologies focusses on low-power wide-area networks (LPWAN) and how M2M businesses will cope after the loss of the GPRS systems that have powered them for so many years.
Long Term Evolution Category M1, or LTE-M as it is more commonly known, is a low-power wide area (LPWA) technology standard, published by 3GPP, that looks to support the Internet of Things through lower device complexity and extended coverage as well as allowing the reuse of the LTE installed base. Long range, or LoRa, is a set of open standards for bidirectional devices and its network implementation is known as LoRaWAN (long range wide area network). In this article, we’ll take a look at these two competing technologies, their pros and cons, and try to get an idea of where this competition may be going and whether one or perhaps none of the proposed solutions looks likely to gain an advantage.
To start let’s take a look at LTE-M. This technology is designed for use by Internet of Things devices that want to connect to a 4G network without a gateway and while using batteries. These so called low-power devices are what is expected to become the bulk of connected devices over the next few years, and will most likely contribute the most to reaching the predicted 50 billion connected devices by 2020. LTE-M technologies are generating a lot of excitement due to benefits such as running on chips that are much cheaper to manufacture due to their having narrower bandwidth and being half duplex.
Being less expensive isn’t the only thing LTE-M has going for it either with extended battery life also being a substantial pull factor towards it. With LTE-M, devices are able to enter a power saving mode and “wake up” only when periodical connections are made, a feature known as extended discontinuous reception (eDRX). There is also a financial factor. The maximum data rate for LTE-M devices is limited to 100 kbits/s which means they are much less taxing on 4G networks. This allows carriers to offer service plans with significantly reduced prices, sometimes as low as some of the old 2G M2M pricing.
Within a LoRa network, LoRaWAN describes the systems architecture being used as well as the communications protocols, while LoRa describes the physical layer of the network. A typical LoRa network will consist of three main components; nodes and endpoints, gateways, and network servers. A node or sensor could be a remotely placed device that senses its environment or tracks and reports changes to it. Nodes in a LoRa network are linked with particular gateways so that any data transferred from the connected nodes or sensors is sent to all gateways and then sent on to a cloud-based server from there.
The network server in a LoRa network is where packets from different gateways are filtered for duplicates, security checks take place, and ACKs are sent back to the gateways. Security is one of LoRa’s biggest selling points as these systems conduct security procedures at two different layers, the network and applications layers. Network level security ensures that nodes and endpoints within a network are authentic while application level security ensures that network operators aren’t able to gain access to an end-user’s application data. The use of LoRa networks are secured by advanced encryption standard (AES) security keys such as unique device and application keys.
One of the arguments put forward regarding the contest between technologies such as LTE-M and LoRa, as well as other similarly associated technologies such as SigFox and NB-IOT, is that it is actually less about the technology or its capabilities, and more about the IoT business model. As different business models will look to achieve different objectives, so will different network architectures and, thus, this argument could be entirely correct. If this is the case and business models dictate success over technological capability, then predicting a clear winner between these two competing technologies becomes much more difficult.
Both technologies have their strengths. For national or international coverage, LTE-M would most likely become the preferred choice as it could come within an upgrade package to already existing infrastructures. However, if enhanced control and a focus on applications in generally confined locations, LoRa would probably be the most sensible choice. There is also the possibility that new technologies for LPWAN or LPWA will be developed within the near future and make both LTE-M and LoRa obsolete, such would appear to be the way of the world thanks to the breakneck speed of technological innovation at the dawn of the Fourth Industrial Revolution.