LoRaWAN is a technology that is rapidly gaining popularity in the field of Internet of Things solutions. At the same time, for many clients it remains little studied and exotic, which is why there are many myths and misconceptions around it. In 2018, amendments to the legislation on the use of LoRaWAN frequencies were adopted in Russia, which expand the possibilities for using this technology without a license. We believe that now is the best time to start using this technology in solving real business problems.
In this article, we will look at the basic principles of LoRaWAN, options for building your own network and using third-party providers, and also talk about our products that support LoRaWAN.
What is LoRaWAN
LoRaWAN is a set of protocols that define the physical and network data transfer layers for low-power, low-power devices operating over long distances. The abbreviation LoRa means Long Range, that is, long data transfer distances, and WAN (Wide Area Network) means that the protocol also describes the network layer.
Unlike the well-known GSM/3G/LTE/WiFi wireless communication standards, LoRaWAN was originally designed to simultaneously serve a huge number of low-power subscriber devices. Therefore, the main emphasis is on immunity from interference, energy efficiency and range. At the same time, the maximum data transfer rates are limited to only a few kilobits per second.
Like a cellular network, LoRaWAN has subscriber devices and base stations. The communication range of the subscriber unit with the base station can reach 10 km. At the same time, subscriber devices usually have autonomous battery power and are in power-saving mode most of the time, waking up occasionally for short-term data exchange with the server. So, for example, water meters can wake up every few days and transfer the current value of the consumed water volume to the server, and the rest of the time they are in sleep mode. This approach allows you to get devices that work up to several years without the need to replace batteries. The task of LoRaWAN devices is to transmit / receive the necessary data from the base station as quickly as possible and free up the air for other devices, so the network has strict rules for the time it takes to air. Devices transmit data only after receiving confirmation from the base station, this allows you to control the load on the air from the server and evenly distribute data exchange sessions in time.
The LoRa standard describes the physical layer, signal modulation in the frequency bands 433 MHz, 868 MHz in Europe, 915 MHz Australia/America and 923 MHz Asia. In Russia, LoRaWAN uses the 868 MHz band.
How does LoRaWAN work?
Since LoRaWAN operates in an unlicensed range, it greatly simplifies the deployment of your own network with base stations, in which case you do not need to depend on telecom operators. In addition to deploying your own network, you can use the networks of existing operators. LoRaWAN providers already exist around the world and have recently begun to appear in Russia, for example, the operator to its LoRaWAN network in many cities.
In Russia, LoRaWAN usually operates in the range of 866-869 MHz, the maximum channel width occupied by one subscriber device is 125 kHz. This is how data exchange using the LoRaWAN protocol looks like on a spectrogram recorded by habrauser Ruslan Nadyrshin using SDR.
Since 2018, amendments to laws have been adopted in Russia that significantly reduce restrictions on the use of 868 MHz frequencies. You can read more about the new legislation regulating LoRaWAN frequencies in Russia .
Base station - in the terminology of the LoRaWAN standards, it is called a gateway or hub. By purpose, this device is similar to the base stations of conventional mobile cellular networks: end devices are connected to it and follow its instructions for choosing channels, power, time slots for data transmission. Base stations are connected to a centralized software server, which has access to the status of the entire network as a whole, deals with frequency planning, etc.
Typically, LoRaWAN base stations are connected to a stationary power supply and have stable Internet access. Advantech offers several models of LoRaWAN series base stations with a capacity of 100 and 500 subscriber devices, and the ability to connect to the Internet via Ethernet and LTE.
Subscriber device - a low-power client device, usually self-powered. Most of the time it is in a power-saving sleep mode. Interacts with a remote application server to send/receive data. Stores encryption keys for authentication at the base station and application server. Can be located in the coverage area of ββseveral base stations. Strictly observes the rules for working on the air received from the base station. Devices Advantech are modular I/O terminals, with various analog and digital I/O interfaces and RS-485/232 serial interfaces.
The client can deploy their own LoRaWAN base stations or use existing networks of third-party operators
Public network LoRaWAN
In this architecture, devices are connected to a public network of a third-party operator. The client needs to purchase only subscriber devices and conclude an agreement with the provider, receive keys to access the network. At the same time, the client is completely dependent on the coverage of the operator.
Keep in mind that a public LoRaWAN network may have strict limits on the airtime that a device can occupy, so for applications where more frequent data exchange is needed, such networks may not be suitable.
Before sending data, the device requests permission to transfer, and only if the base station answers with confirmation, the exchange will take place.
When using a third-party LoRaWAN network, the client uses someone else's base station infrastructure and depends on the provider's coverage and its data transfer restrictions
This approach is convenient, for example, when replacing subscriber devices in urban areas, where the necessary infrastructure already exists. For example, to install sensors in residential buildings and with a small amount of transmitted data, to collect data from electricity or water meters. Such devices can transmit data every few days.
Private network LoRaWAN
When deploying a private network, the customer independently installs base stations and plans coverage. This approach is convenient when you need full control over the network, or at sites where there is no operator coverage.
In a private network, the customer has full control over the infrastructure
In this architecture, the customer makes a one-time investment in equipment for deploying base stations and then does not depend on services and third-party operators. This option is suitable for building a network at remote agricultural facilities, production, etc. Own network makes it easier to scale the existing infrastructure, increase coverage, the number of subscriber devices and the amount of transmitted data.
Subscriber input-output terminals
Technical specifications
- Versions for all world LoRaWAN frequency bands
- Communication range with the base to 5km
- Extension modules for connection peripherals
- Built 4000mAh battery
- GPS module (Galileo/BeiDou/GLONASS)
- IP65 protection
- USB programming
Series devices are modular terminals for connecting various peripheral devices to the LoRaWAN network. With their help, you can collect data from any digital and analog sensors, such as thermometers, hygrometers, barometers, accelerometers, etc., control other devices via RS-232/485 interfaces. It has a built-in 4000mA battery, which can work autonomously for up to six months. Integrates with solar panels to charge the battery. The built-in GPS receiver allows you to accurately determine the location of the device, which simplifies accounting and installation: devices can be mounted without first entering into the database, and after installation they are automatically tied to the object based on the received coordinates.
Programming and configuration is performed via a conventional USB interface and does not require additional controllers and programmers, so it can be done on site using a laptop.
Interface modules
A set of interfaces for connecting external devices to , is implemented using interface modules that are connected from below. to one terminal one interface module can be connected. Depending on the customer's tasks, these can be digital or analog inputs/outputs, or serial interfaces. The interface contacts are protected by a sealed connector with an M12 threaded connection.
- - 4 analog inputs and 4 digital inputs
- WISE-S615-A - 6 channels for RTD (Resistance Temperature Detector) thermometer
- WISE-S617-A - 6 digital inputs, 2 RS-232/485 serial interfaces
Wzzard LRPv2 Series Sensor
BB series sensors these are LoRaWAN subscriber devices designed for data collection in harsh environments and designed for quick installation. They have a magnetic base and can be securely attached to metal surfaces without additional fasteners, which allows you to quickly deploy a network of multiple devices. Sealed interface connector, located on the side, is designed to connect external peripherals and sensors.
Technical specifications
- Work in all frequency bands LoRaWAN 868/915/923MHz
- Magnetic mount on a metal surface
- Interfaces RS485 (Modbus), 4 analog inputs, 2 digital outputs, 1 digital output
- Sealed connection of the interface cable
- Operates on 2 AA lithium batteries, solar panels or 9~36V power supply
- Protection class IP66
- Operation at temperatures -40 ~ 75Β°C
LoRaWAN Base Stations
Advantech offers a full range of devices for deploying a private LoRaWAN network. Series Gateways are used to connect subscriber devices, such as ΠΈ , and transfer data to the application server. The line includes models that support simultaneous connection of 100 and 500 subscriber devices. The gateway is connected to the Internet via Ethernet, versions with a built-in 4G modem are also available. Support for MQTT and Modbus protocols for data transfer to the application server.
Technical specifications
- Support for all LoRaWAN bands
- Simultaneous maintenance of 100 or 500 subscriber devices
- Ethernet connection
- Optional: built-in LTE modem
- Built-in VPN server/client
Conclusion
LoRaWAN technology deservedly attracts a lot of attention in the industrial solutions environment, and even today it allows you to effectively solve many business problems. But for most customers, LoRaWAN is still a little-known and incomprehensible technology. We believe that in the near future it will be as widespread as classic cellular networks, which will make it easier for our customers to implement standalone IoT solutions.
Source: habr.com