LoRa is a radio modulation technique that is essentially a way of manipulating radio waves to encode information using a chirped (chirp spread spectrum technology), multi-symbol format. LoRa as a term can also refer to the systems that support this modulation technique or the communication network that IoT applications use.
The main advantages of LoRa are its long-range capability and its affordability. A typical use case for LoRa is in smart cities, where low-powered and inexpensive internet of things devices (typically sensors or monitors) spread across a large area send small packets of data sporadically to a central administrator.
Spreading Factor (SF)
The chirp spread spectrum technology uses so-called “chirps,” which are signals with a frequency that moves up or down (up-chirp or down-chirp respectively) at different speeds. The spreading factor (SF) determines the speed of a chirp.
A high SF means a broadcast has higher range and penetration, at the cost of increased power consumption. A lower SF is faster and transmits more data at the same bandwidth and time.
Low Power Wide Area Networks (LPWAN)
A low-power wide-area network (LPWAN) is a type of wireless telecommunication network that allows connected devices to have long-range communications capabilities at a low bit rate. LPWANs are typically used in asset monitoring and management in smart cities and industrial internet of things deployments. This is in contrast to wireless wide-area networks (typically used by large corporate organizations) that carry more data and use more power. Examples of LPWAN technology are Lora/LoraWAN, Sigfox, MIoTy, Wi-SUN, LTE-M, and NB-IOT.
LPWAN technology has an operating range of up to ten kilometers, and because it is a relatively simple and lightweight protocol, the devices and hardware are relatively inexpensive. The transceivers (small battery-powered devices) also use little power, allowing them to run for up to twenty years.
LoRaWAN is a low-power, wide area networking protocol built on top of the LoRa radio modulation technique. It wirelessly connects devices to the internet and manages communication between end-node devices and network gateways. Usage of LoRaWAN in industrial spaces and smart cities is growing because it is an affordable long-range, bi-directional communication protocol with very low power consumption — devices can run for ten years on a small battery. It uses the unlicensed ISM (Industrial, Scientific, Medical) radio bands for network deployments.
An end device can connect to a network with LoRaWAN in two ways:
Over-the-air Activation (OTAA): A device has to establish a network key and an application session key to connect with the network.
Activation by Personalization (ABP): A device is hardcoded with keys needed to communicate with the network, making for a less secure but easier connection.