Machine to Machine, or M2M, will be critical to the success of IoT devices in the coming years. As more devices undergo design and testing, it will be essential that manufacturers can rely on low powered networks that deliver sufficient bandwidth. If you’ve been following the technology, you will know that these networks all fall under the category of LPWAN, or Low Powered Wide Area Network.
What you might not know, is that LPWAN is not a standard, and there are currently numerous companies who are all competing for relevancy in the low powered network space.
Understanding the leading technologies will give you a good idea of what LPWAN is going to be able to deliver, while also allowing you to understand the shortfalls of both the proprietary and open technologies that are currently in use and in development.
LoRa is a technology that has already been successfully deployed by over 100 commercial operators in multiple countries. While the technology is based on an open source standard, it currently only operates on chips from SemTech, a major investor in the standard.
LoRa can provide relatively high bandwidth levels, with up to 100kbps being achieved on the fastest European deployed network. Within the United States, existing LoRa networks provide between 0.9 and 22kbps.
Power efficiency is high to excellent on a LoRa deployment and devices can operate autonomously for up to 10 years on battery power.
The standard employs network and application level security, as well as device specific key security.
Urban density range is a maximum of 7.2km which is significant, although still falls slightly short of some competing technologies.
The SigFox UNB standard is highly energy efficient, is currently deployed, and is technically an open standard. However, much like LoRa being limited to networks using SemTech chips, deployment is limited to Sigfox networks.
As one of the oldest standards in LPWAN, it is also one of the most limited. Offering only 100Hz of node bandwidth, connected devices are limited to 140 messages per day, in sizes of up to 12bytes. Security is 16bit, compared to the 32bit security implementations on LoRa. However, Sigfox does have an advantage in the fact that it features an effective urban range of up to 9.5 kilometers.
Despite bandwidth limitations, this technology is popular in European markets. Power efficiency means 10 year operating life for devices on battery power, which is currently the industry standard for LPWAN technologies.
NB-Fi is another strong contender that is currently in deployment. It is marketed as a full stack solution that can provide reliable service in even the most challenging environments. This is achieved through superior spectrum utilization (up to 100%). This means that in ideal conditions, range can exceed 16km with 99% reliability. It is more power efficient than LoRa, and the standard utilizes robust XTEA 256-bit security, which is currently the highest of the major technologies in deployment. Its main limitation is that it provides roughly the same bandwidth as SigFox UNB.
Are These Three Technologies Sufficient for IoT in the Future?
While LoRa, SigFox, and NB-Fi are amongst the current leaders in deployed technology, they all lack in one key area – total available bandwidth.
While current low power devices on M2M networks can make do with the bandwidth restrictions, those same restrictions are limiting innovation and feature sets for new devices and network services.
One solution that is currently in development, is LTE-M. Based on existing GSM technologies, this upcoming solution will cater to the next generation of connected devices and sensors, with almost twice the bandwidth of LoRa.
The downside of the increased bandwidth is a reduced urban range of .64 kilometers per node, and battery lifetime per device expected to be only half of current deployments.
LTE-M is still in development, so it is possible that these capabilities and limitations will change before the first estimated commercial deployment in 2020.
Leading research firms estimate that there will be over 20 billion connected devices in use by 2020. Low powered networks will be necessary to facilitate growth, but those networks should also grow in capability, or face being left behind.
LTE-M is an interesting step forward, regardless of limitations in range and power efficiency. At this time, it appears that we must still wait before there is a single LPWAN solution that delivers power efficiency, without compromising effective range or total bandwidth.