As the market for low cost, low power Internet of Things (IoT) networks is heating up (SigFox, LoRa, etc), the location and tracking of the sensors and devices connected to these networks is coming up as a significant use case.
However location often means GPS that comes with both a significant bill of material and power consumption.â€¨â€¨But what is not very well known is that the LoRaWAN specification offers to use the network as a mean of location.
The French broadband technology supplier Sagemcom is at the forefront of this opportunity with their LoRa technology offering announced two weeks ago.â€¨â€¨Similar to what it does on the broadband market, with LoRa Sagemcom positions itself as a technology supplier to telecom operators.
The company supplies an end to end network with a core network, a cloud for applications, antenna/gateway down to radio modules for sensors in the field. â€¨â€¨One of the reasons why Sagemcom selected LoRa was the fact it is an open standard supported by many wireless operators and having geo-location as a feature.
â€¨â€¨“Geolocation is a must have for IoT and it is part of the LoRa Standard,“ explained Thierry Lestable, Technology and Innovation Manager at the CTO Office of Sagemcom. “what we want to do at Sagemcom is to make the most out of it.“
LoRa well suited for Network-based Geolocationâ€¨Unlike some other IoT network technologies, LoRa is well suited for geolocation.â€¨â€¨
“At the physical layer the radio signal used by LoRa is somewhat closed to a radar signal, thanks to its Chirp Spread Spectrum (CSS) technology. The antenna Gateway can very precisely detect the arrival of the signal emitted from the device,“ explainedÂ Thierry Lestable.
“based on that we use a technology called DTOA (difference time of arrival) very similar to existing technologies in the cellular world: each base station records the time of arrival of the signal from the device and a position is calculated from that.“
â€¨â€¨So far the location precision announced by Semtech (LoRa silicon vendor) in its 3GPP standard contributions is between 10 and 100 meters. But Sagemcom is confident on the fact it could be improved depending on wireless conditions and density of network.
â€¨â€¨“Unlike in a cellular network where a device “talks“ to a limited number of antennas, in a dense LoRa network each device signal is received on average by 12 and up to 20 antennas. Obviously each additional antenna adds precision to the location of the object,“ added Lestable.