A LoRa gateway is a wireless communication technology designed for long-range, low-power communication between devices for the Internet of Things (IoT). The LoRa gateway receives data from devices, forwarding it to a network server, which manages the network and takes care of data routing and processing.
Gateways typically use a dedicated LoRa concentrator chip to receive and demodulate signals from end devices. It then converts the demodulated signals into IP packets and sends them to a server using a backhaul network via a cellular or Ethernet connection. LoRaWAN is the network protocol that connects the LoRa signal.
LoRa gateways are essential components as they enable long-range communication between devices, providing internet connectivity. These gateways can also have a LoRa network server (LNS) installed. Gateways can be single and multi-channel depending on the requirements.
In this article, we will discuss the LoRa gateway architecture and available software platforms.
A block diagram of the LoRa gateway.
The LoRa gateway architecture.
The gateway architecture
1. The physical layer
The physical layer of the LoRa gateway consists of a radio transceiver capable of receiving LoRa signals from end devices. The gateway typically uses a dedicated LoRa concentrator chip that can demodulate LoRa signals.
The physical layer of the LoRa gateway.
There are several types of concentrator chips available:
- Semtech SX1301: a highly integrated baseband processor for long-range, low-power wireless communication using LoRa technology. It is often used in professional-grade LoRa gateways and supports up to eight channels for simultaneous reception of LoRa signals.
The Semtech SX1301 concentrator chip.
- Semtech SX1308 : a low-cost, low-power LoRa concentrator chip that is commonly used in indoor and outdoor gateways. It supports up to 8 channels and can handle up to 27 packets per second.
- Semtech SX1257/58 : single-channel LoRa transceivers that are often used in low-cost, low-power gateways. They are capable of receiving and transmitting LoRa signals at a range of up to 15 km.
- IMST iC880A: A highly integrated LoRaWAN gateway module that includes a Semtech SX1301 hub chip and a low-power microcontroller. It is widely used in DIY and professional LoRa gateways.
- RAK831 Wireless RAK : a LoRaWAN gateway module that features a Semtech SX1301 hub chip and a Raspberry Pi compatible interface. It's a popular choice for hobbyists and DIY projects.
There are also shields available for the above chips that work with Raspberry Pi.
Each concentrator chip works with RF front ends, which handle the RF singles. Power amplifiers (PA) are used to send and low noise amplifiers (LNAs) are used to receive messages between long-range devices.
2. The data link layer: responsible for converting the raw demodulated LoRa signals into packets that can be sent over the network.
The data link layer of the LoRa gateway.
3. The network layer: responsible for forwarding LoRa packets to the network server. This is typically done using a backhaul network, such as a cellular or Ethernet connection.
The network layer of the LoRa gateway.
Quectel EC200U is currently one of the most common 4G modules, ideal for use when Ethernet or WiFi are not available. However, most processor boards come with built-in Ethernet and Wi-Fi chips.
The Quectel EC200U processor board.
4. The processor: responsible for controlling the gateway hardware, managing the network interface, and running the gateway software. It is typically a microcontroller or a system on chip (SoC) that runs a real-time operating system (RTOS).
The network layer – the processor side of the LoRa gateway.
Types of Single Channel LoRa Gateway Processors:
- ESP32: a low-cost, low-power microcontroller commonly used in IoT applications. It has built-in Wi-Fi and Bluetooth connectivity and can be used as a LoRa gateway with a compatible LoRa hub card.
- BeagleBone Black: a powerful single-board computer designed for embedded applications. It can run a full Linux operating system and is capable of supporting a LoRa gateway software stack.
Types of multichannel LoRa gateway processors:
- Raspberry Pi 4: A more powerful version of the Raspberry Pi, capable of supporting multiple LoRa channels. It can run a LoRa gateway software stack and can be easily integrated into a multi-channel LoRa hub board such as the RAK2245.
The Raspberry Pi 4 multi-channel gateway processor.
- Intel NUC : a small form factor computer commonly used for industrial and commercial applications. It is capable of running a full Linux operating system and can support a multi-channel LoRa gateway software stack.
- NVIDIA Jetson Nano: A low-cost, high-performance computer designed for AI and machine learning applications. It can also be used as a multi-channel LoRa gateway with a compatible LoRa hub card.
5. The software stack: Consists of multiple layers of software that work together to provide LoRa gateway functionality. This includes the firmware running on the gateway processor and the LoRaWAN stack that implements the LoRaWAN protocol.
The application layer with the software stack.
- The Things Portal: An open source LoRaWAN gateway software stack developed by The Things Network community. It works with multiple LoRa hub cards and supports multiple channels and frequency bands.
- Semtech Packet Forwarder: LoRa gateway software stack developed by Semtech, creator of LoRa technology. It works with Semtech's SX1301 hub chip and can be used with various microcontrollers and single-board computers.
- ChirpStack Gateway OS: An open source LoRaWAN gateway software stack from the ChirpStack community. It works with multiple LoRa hub cards and supports multiple channels and frequency bands.
- LoRa Gateway Bridge: LoRa gateway software stack developed by the LoRa Alliance. It works with several LoRa hub boards and can be used with different types of microcontrollers and single-board computers.
- TTN Gateway : An open source LoRaWAN gateway software stack from The Things Network community. It works with multiple LoRa hub cards and supports multiple channels and frequency bands.
6. The antenna: responsible for receiving LoRa signals from end devices. This is typically a high-gain directional antenna mounted on the roof or at a high point to ensure maximum coverage.
The LoRa antenna.
Overall, a LoRa gateway is a complex system that requires specialized hardware and software to function properly. It plays a critical role in LoRaWAN networks, providing a bridge between end devices and the network server – enabling long-range, low-power communication with IoT devices.