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LoRaWAN Sensor Design: Key Components and Vendors

This article explores the design of LoRaWAN sensors, outlining key components and popular vendors.

Introduction:

LoRaWAN, short for Long Range Wide Area Network, utilizes LoRa modulation in both the physical (PHY) and MAC layers. This extends LoRa’s physical communication capabilities, making it compliant with internet protocols.

A typical LoRaWAN network comprises end devices, gateways (base stations), and a core network server. End devices connect to multiple gateways, communicating via single-hop connections, as illustrated below.

LoRaWAN network

Figure-1: LoRaWAN network

Gateways are interconnected and interfaced with the core network server using standard IP connections. All gateways are connected to this central server. Communication is bi-directional, but uplink traffic (from the end device to the network) is predominantly used for various applications. This network topology is known as “star-of-stars”.

Communication between end devices and gateways happens on different channels and at varying data rates. These data rates range from 300 bps to 5 kbps, with a bandwidth of approximately 125 KHz. Different data rates support different coverage ranges.

LoRaWAN sensor design

Figure-2: LoRaWAN Sensor design

The figure above shows a simplified LoRaWAN sensor design. Typically, it consists of:

Power Supply: This can be an external power plug or a battery.
MCU (Microcontroller Unit): The MCU houses the LoRaWAN protocol stack and provides various functionalities depending on the application.
LoRa Radio: This includes the LoRa-based transceiver, antenna, and matching circuits.
Peripherals: These are sensors tailored to specific use cases, such as accelerometers, temperature sensors, proximity/IR sensors, and humidity sensors. They can also include relay or display devices.

For instance, a LoRa parking sensor might incorporate a proximity/IR sensor. LoRa sensors can be designed in various ways, with Figure 2 illustrating designs based on either a LoRa module or a LoRa modem.