LPWAN technology is a highly practical technology in the field of the Internet of Things (IoT). This technology and its protocols are used to connect IoT devices to one another. LPWAN stands for Low Power Wide Area Network, which means a long-range technology with low power consumption. LPWAN features three distinct protocols, each with its own advantages and disadvantages that set them apart: LoRaWAN, Sigfox, and NB-IoT, each of which will be discussed separately.
The LoRaWAN Protocol
The LoRaWAN protocol can be considered one of the most well-known and important protocols in an LPWAN network.
- Frequency Bands: It operates in the unlicensed or ISM frequency band. Specifically, it works on the 868 and 433 MHz bands in Europe, 915 MHz in America, and the 430 MHz band in Asia.
- Application & Range: LoRaWAN is designed for networks and devices requiring wireless, long-range connections.
- Power Efficiency: One of its unique features is extremely low power consumption. Since IoT devices mostly run on batteries, low power usage is crucial. Devices using the LoRaWAN protocol can operate for several years without needing a battery replacement.
- Data Rate: The data transmission rate in this protocol is around 27 kb/s, which is completely normal for the IoT space.
- Coverage: Each Gateway in this network can cover up to 15 kilometers in open areas, though this varies slightly for suburban and dense urban environments.
How a LoRaWAN Network Works
A LoRaWAN network consists of four main components:
- End Device
- Gateway
- Network Server
- Application Server
Operational Flow: Data is first collected by End Devices (such as sensors) and transmitted to the Gateways using the LoRa network. Next, the Gateways forward this data to LoRaWAN Servers via the internet and communication channels (such as LTE, 3G, or Wi-Fi). After the information is processed and analyzed by the server, the required data is delivered via the internet to users or Application Servers.
- Topology: The network topology used in LoRaWAN is a Star topology.
- Security: Information within these networks is encrypted using AES, ensuring users can be confident about data security. However, devices in a LoRaWAN network operate across three different classes.
Different Classes in the LoRaWAN Protocol
- Class A
- Class A devices support a two-way communication channel between themselves and the Gateway.
- Uplink messages (from the device to the server) can be transmitted at any time (randomly).
- Following an uplink, the device opens two specific receive windows (at 1s and 2s) to get a response from the server. If the server does not reply in either of these windows, it must wait for the next scheduled opportunity. The server can respond in either the first or the second receive window, but it must not use both.
- Class B
- Class B devices build upon Class A by adding scheduled receive windows for downlink messages from the server.
- Class C
- In this class, the receive windows remain continuously open so devices can receive responses instantly.
- The main drawback of this class is its very high power consumption.
The LoRa Alliance
The LoRaWAN protocol was created by a French company named Semtech alongside hundreds of other corporations like IBM, Cisco, HP, and others. Joining this alliance, utilizing LoRaWAN features, and using its hardware equipment is completely free for any company, which has driven LoRaWAN to grow significantly faster than its competitors.
