What is LoRa and why is everyone talking about it? Find out in our blog originally written for Cambridge Wireless by AMIHO.
Over the years a number of new technologies have popped up on the radar that supposedly offer the wireless connectivity solution we have all been waiting for. Usually these are received with a cynical sneer, or a cry of ‘like we need another new protocol’ (Weightless – what happened to that?).
We can all reel them off – CAT, LTE, Thread, Bluetooth, SigFox, ZigBee, M-Bus and now the flavour of the month, LoRa. But in the case of LoRa, something different does seem to be happening – not because of political lobbying, not because of vendor push, but because of the enthusiastic take up by the designers and end users.
LoRa offers a Long Range radio solution by using spread spectrum techniques and using the sub-gigahertz ISM part of the spectrum (which allows longer range and better transmission characteristics already, such as Wireless Meter-Bus, for example). It can be used either as a point to point long range radio from device to device or device to gateway, so it doesn’t require any large-scale infrastructure for straightforward connection projects, or it can be used with the LoRaWAN protocol (WAN means Wide Area Network) which requires LoRaWAN masts and gateways. However because of the range LoRa provides, up to 15km radius from each mast, very few masts are needed to cover a whole city area and this is proving to be a key factor in its uptake – the promise of cost effective city-wide coverage.
Smart City LoRaWAN networks are being piloted in a number of cities throughout Europe and are allowing local authorities, companies and individuals to develop and test all sorts of exciting Internet of Things (IoT) solutions at an affordable cost point. The extra range opens up all sorts of applications, which have specific connectivity problems, from remote monitoring of large scale assets to improving the success rate for connecting smart meters. Sectors being addressed are far ranging – wearable technology, agriculture, underground, safety, building management, smart homes, medical, and so on.
Having named but a few applications above, and with predictions of 50 billion connected devices by 2020, one of the problems the world is facing is noisy, overcrowded airwaves due to the sheer numbers of devices all trying to send messages at the same time and in the same space. What will devices do to be heard over the noise? Shout louder? Send messages more often?
LoRa does address this issue to some extent, with its spread spectrum redundant coding scheme, that makes it more resilient to interference within a channel and so reduces the need for retransmission and hence the number of messages that need to be sent. In fact, the redundant coding scheme allows transmissions with orthogonal coding schemes to occupy the same spectrum simultaneously and still be discriminated from each other – albeit with a small reduction in sensitivity.
In addition LoRaWAN provides an additional layer over LoRa and FSK (frequency shift keying) and has other protocols to help improve reception of signal and minimise interference. This uses ‘Cognitive Radio’ features – where the radio can intelligently choose its data rate and power level to use the shortest, quietest message possible. This minimises interference to other users – crucial in the soon to be crowded unlicensed radio bands. More importantly, this uses less energy and so extends the battery life for the billions of battery-powered connected devices.
It remains to be seen whether LoRa and LoRaWAN will rule the airwaves, but with its promise of accessibility, long range and low power, it’s certainly looking like a move in the right direction.