Basic technical concepts that will help you understand LoRa and LoRaWAN (Low Power Wide Area Network) in a few minutes

The objective of this article is to clarify the basic concepts to start using LoRa and LoRaWAN. If you want to delve deeper into LoRaWAN, at the end of the article you will find a list of links to articles with detailed information.

What is LoRa and LoraWAN

LoRa is a proprietary wireless technology, it was developed by Cycleo in France, Cycleo was acquired by Semtech in 2012. LoRa uses spread spectrum modulation. The use of this type of modulation allows for better noise tolerance and thus achieve long distances with very low energy consumption. LoRa is the protocol at the Physical layer level (OSI Layer Level 1)

LoRaWAN is the communication protocol at the Network level (OSI Layer Level 2,3) that goes over the LoRa physical layer. The LoRaWAN communication protocol is open, this allows many manufacturers to develop devices and thus reduce the costs of these.

Analogously to an Ethernet network, it could be said that LoRa are the cables that connect the devices in an Ethernet network and LoraWAN is the communication of the devices at the level of the MAC address and the IP network address of the devices in the Ethernet network.

From now on we will refer to LoRaWAN as the LoRa, LoRaWAN set.

Advantages of Using LoRaWAN

• The communication between devices can reach several kilometers.
• Very low energy consumption, allowing devices to last for years using a single battery.
• The cost of LoRaWAN devices is affordable for any project.
• It is scalable and allows the communication of thousands of devices through one or several gateways.
• Fast learning curve.
• It offers a high level of security between the devices on the network, from the nodes to the application server.

Elements in a LoraWan Network

• Nodes (End points): Final devices that send or receive information through LoRaWAN, these can be sensors, actuators, trackers.
• Gateways: It is the device to which the nodes are connected by LoRaWAN and allows the communication of these with the Network Server.
• Network Server: It is the software that controls the network and the logic of communications between the nodes and the Gateway, in this way it avoids the duplication of packets, the access of the devices. The Network Server in some cases is embedded in the same Gateway and the advantage of this is a reduction in the total solution cost and the disadvantage is that it limits scalability.
• Application Server: It is the software that will process the data that is communicated through LoRaWAN, this software is completely independent of the LoRaWAN network and depending on the Network Server it can communicate for example with MQTT, Modbus TCP, REST API, among others.

Classification of LoRaWAN Devices (Nodes) According to Their Consumption

• Class A: These are the devices that have maximum energy savings since they only send data when necessary and after sending this information they have a few seconds of waiting, to receive data from the Gateway, after this time they return to sleep mode, this allows the devices to communicate for years with a single battery
• Class B: These are devices in which the reception message time can be configured, once this time has passed, it goes into sleep mode.
• Class C: Devices that are constantly active, this requires them to be connected to the power supply.

Calculation of the Battery Payload Time

Estimating the payload time of a battery is not an easy task to perform in LoRaWAN nodes since it depends on many factors: the frequency with which the data is sent/received, the environment (obstacles), the temperature, spreading factor, number of samples (Payload).

In the following example you can see the estimation of the battery life using a spreading factor of 7 and a sample every X minutes.

What is the Spreading Factor?

It is a parameter in the LoRaWAN configuration, which allows spacing the data transmitted by LoRaWAN to be able to have a greater range or allow a greater tolerance in environments with a lot of noise, making an analogy with spoken language it would be like spelling, the spreading factor goes from SF7 to SF12 from less to more spacing.

Are all Devices Compatible with each other?

The short answer is no, that is why it is important that when choosing a device for a LoRaWAN network it is certified by the LoRa Alliance foundation, even so, it must be taken into account that depending on the geographical location the frequency bands used vary, in Europe the bands used are 433 MHz and 868 MHz, that is why it is important to know in which band the devices that are going to be acquired operate.

What should I Know about the LoRaWAN Gateway?

Something important to keep in mind is whether the Gateway includes the Network Server (The administration of the LoRaWAN network in the same gateway) or not.

The number of nodes that can be connected to a Gateway will depend on:

1. Simultaneous channels with which the Gateway can work.
2. If it is a Full Duplex or half duplex Gateway since the latter cannot receive data while transmitting (something very unusual) since the sending of data from the Gateway to the nodes does not usually occur
3. RSSI/SNR: RSSI (Received Signal Strength Indicator) SNR (Signal to Noise Ratio)
4. Gateway resource loading
5. If it includes the Network Server, one of the limitations will be the amount of data that can be communicated from the LoraWAN Nodes to the Application Server.

In LoRaWAN there is no exact number that determines the nodes that can be connected to a Gateway as such, since it will depend on the factors described above.

Why is it Important to Define the Network Server?

The network server will define the scalability in the future and the ease of administration of the LoRaWAN network since it can be centralized or decentralized.

Network Server as a Dedicated Server (Centralized)

The network server is located on a server independent of the gateways, this allows high scalability of the LoRaWAN network and great ease of configuration, on the other hand the price of the project increases in cost, but this will always be advisable for large projects.

Network Server Embedded in the Gateway (Decentralized)

The network server is embedded in the Gateway for the configuration of the LoRaWAN network of that specific Gateway, in this way the cost of the LoRaWAN network is reduced and in this case the application server can work with the data directly from the Gateway.

Does Using LoRaWAN Have Disadvantages, when should I Take it into Account?

More than disadvantages, it could be said that they are limitations of the technology, since depending on the application or problems that we want to solve, we will have to use the appropriate technology on the one hand the distance that it can reach, the bandwidth and the energy consumption

In the following graph, you can see the technology that should be used depending on the distance

In the following graph you can see the appropriate technology according to the bandwidth

From these two graphs we can deduce that LoRaWAN is a technology designed to communicate devices that need little bandwidth and are far apart.

In Logitek, ER-Soft we have wireless solutions that apply different technologies (WiFi, Bluetooth, Bluetooth LE, Wirepass, LoRaWAN, NB-IoT, mobile communication among others), if you have any questions or a project where we can help you, do not hesitate to contact us.

If you are interested in learning more about LoRaWAN technology you can read the following articles.

• Getting started with LoRaWAN I – Theory
• Getting started with LoRaWAN II – Nodes and Gateway
• Getting started with LoRwaWAN III – Network Server
• What is LoRaWan
• LoRaWAN vs NB-IoT: competition or complementary?
• Why LoRaWAN fits so well with Industry 4.0
• Glossary of LoRaWAN technology
• LoRaWAN regional parameters
• Use case: LoRaWAN for warehouse management
• Use case: LoRaWAN for equipment and outdoor facilities
• Use case: LoRaWAN in industry
• LoRaWAN Gateway: the key element of the network