The main advantage of LoRa technology is a highly competitive market of equipment manufacturers and suppliers, full compatibility of devices from different manufacturers. Base stations (LoRaWAN® gateways) and LoRaWAN® sensors from different manufacturers can be connected to servers. An open and accessible standard guarantees the user that the system for collecting, transmitting and using data will not depend on a particular manufacturer, supplier or integrator. LoRaWAN® is a global long-range network, advanced technology, that helps realize the concept of "smart city". It provides a reliable connection between large number of sensors and their long-term operation.
LoRaWAN® is a promising wireless communication technology with high reliability and noise immunity, and also requires low power consumption from end devices.
The LoRa abbreviation combines the LoRa modulation method in LPWAN wireless networks and the open LoRaWAN® protocol. This protocol is used for communication between LPWAN gateways and end devices.
When the final device starts to transmit data, all available gateways (base stations) listen to it. Then they send the information to the network server, which, according to the parameters of signal quality, distance to the device and other metadata, decides which base station should respond to the device. And then the data is sent to the application servers.
A feature of this technology is the reliability of data transmission and the distance over which information can be transmitted (10-15 km). One base station can serve more than a thousand devices, and the connection is two-way. LoRa technology provides data transfer rates in the wireless channel from 0.3 to 50 Kbps.
The LoRaWAN® networks laid out in a star-of-stars topology have base stations relaying the data between the sensor nodes and the network server through gateways that form transparent bridges. With this approach, it is usually assumed that the network operator owns the gateways and the central server, and the subscribers own the end nodes. Subscribers have the possibility of transparent two-way and secure data transmission to end nodes.
It should also be noted that the efficient transmission of information and control of mobile devices is ensured through several gateways simultaneously and the absence of binding at the end nodes. Thanks to this feature of LoRa technology, free data exchange is possible, for example, between wireless sensors placed on cargo containers.
Devices of this class are used when the minimum power consumption is required with the advantage of data transmission to the server. The initiator of the communication session is the end node, sending a packet with the necessary data, and then allocating two windows during which it waits for data from the server. Thus, data transfer from the server is possible after the connection of the end device. An end device can enter low-power sleep mode as long as its own application determines it: there is no network requirement for periodic wakeups.
The main difference from "Class A" devices is the allocation of an additional receiving window, which the device opens according to a schedule. Class B devices synchronize to the network using periodic beacons and open downlink "ping slots" at scheduled times. To assemble the schedule, the end device performs synchronization on a special signal from the gateway. Thanks to this window, the server has the opportunity to start transmitting data at a certain time, with a determined delay.
Devices in this class have an almost continuous window for receiving data and close it only while transmitting data. This allows them to be used to solve problems that require obtaining a huge amount of data. Based on this, the network server can initiate a downlink transmission at any time, as long as the end device's receiver is open, so there is no delay.