Introduction To LoRaWan
What is LoRa®?
LoRa is a long-range wireless communication technology that complements NB-IoT and LTE Cat M1. Compared to the traditional cellular techniques it can achieve extremely long ranges ( 100km+ LOS ) at the cost of data rate.
Because of this limitation (< 50kbps) and the constraints on duty cycle LoRa is most suitable for non-real time applications, where large delays can be tolerated.
LoRa uses license-free sub-gigahertz radio frequency bands like 433 MHz, 868 MHz (Europe) and 915 MHz (North America).
It enables long-range transmissions (10km+ in rural and up to 2km in urban), while keeping power consumption extremely low (sub uA).
The technology is presented in two parts: LoRa, the physical layer and LoRaWAN (Long Range Wide Area Network), the upper layers. LoRa is a physical layer technology utilizing chirp spread spectrum (CSS) modulation. It is the first low cost implementation of CSS for commercial use.
We are now at the second generation of LoRa chips (announced in January 2018) with even lower power consumption.
LoRa is a flexible solution to Many or several IoT scenarios in different industries.
What is LoRaWAN®?
LoRaWAN is the protocol stack on top of LoRa. It is a media access control (MAC) layer protocol, acting as a network managing protocol for LPWAN.
It is responsible for routing between gateways and end-nodes. Version 1.0 of the LoRaWAN specification was introduced in June 2015. Eversince it has been maintained by the LoRa Alliance.
LoRaWAN defines the communication protocol and system architecture for the network, while the LoRa physical layer enables the long-range communication link.
LoRaWAN is also responsible for managing the communication frequencies, data rate, and power for all devices. Devices transmit asynchronously; when they have data to send. Data transmitted by an end-node device is received by multiple gateways, which forward the data packets to a centralized network server. The network server filters duplicate packets, performs security checks, and manages the network. Data is then forwarded to application servers.
The technology is highly reliable under moderate loads. However, issues exist with acknowledgement transmission.