What is LPWA?
What is LPWA? Like any other technology the IoT has its own language, along with the inevitable three or four letter acronyms. One of those is ‘LPWA’, but what does that mean?
LPWA stands for ‘Low Power Wide Area’ and it describes a kind of network connection that allows IoT devices to run on batteries for a long time. In the early days of IoT, or M2M (Machine to Machine) as it used to be called, the most popular applications involved vehicle tracking, so the tracking device could rely on the vehicle for electrical power. The ‘Wide Area’ technology used was nearly always the mobile phone network, typically 2G.
But what if your application has no access to mains power or power from a vehicle? In that case you would have to rely on batteries. Mobile phone networks are of course designed for phones, not IoT devices which may only send a few short messages every day. In theory that should allow your IoT device to work for many years before you need to change the batteries. The problem is that mobile phone networks keep sending little messages to keep the wireless link to the device alive. This means that even when there is no data to send, the electronics in your device are using power to say ‘I’m still here’. This means that even if your application is only sending one or two messages a day, the batteries on a 2G connection will typically need replacing after two years.
What are the low power wireless technologies?
Recognising that mobile phone networks were not optimised for battery powered IoT applications, a number of new technologies have been developed to fill that gap. The most successful of these are LoRa and Sigfox.
If you take a look at our other ‘New to IoT’ postings these include ‘What is Sigfox?’ and ‘What is LoRa?’ . Both Sigfox and LoRa are wide area, long range wireless technologies designed specifically to support IoT applications. They offer the same kind of long range/wide area coverage as mobile phone networks. They are also able to operate on very low levels of power with no ‘keep alive’ messages draining the precious power supply. This makes them ideal for connecting things that have no access to mains or vehicle power.
Between them, these guys started the LPWA network revolution that is powering the IoT. But what’s so revolutionary about LPWA? Before LPWA it was not possible to economically support hundreds of potential IoT applications. Here are some examples of things we can do with LPWA that were not economical to do before:
- Air quality monitoring
- Temperature sensing
- Package tracking
- Skip Hire locating and monitoring
- Waste bin monitoring
- Personal protection (falls) monitoring
- Pipeline flow measuring
- Meter reading (water and gas)
- Smart parking (occupancy detection)
What about low power on mobile networks?
Both Sigfox and LoRa have grown rapidly in the last 5 years and now support over a hundred million IoT connections globally. While LoRa and Sigfox were building networks and winning customers, the GSMA organisation of mobile operators were working on their own LPWA standards. These are now becoming more widely available in the shape of two technologies, one supporting mobile applications known as LTE-M or Cat M1, the other is called NB-IoT or NB1. Both of these offer low levels of power consumption with NB1 more suited to static applications.
Find out more about why LTE-M is a great choice for low power mobile applications.