Which technology is most suitable for a low-power, long-range IoT sensor node?

• A. LoRa
• B. Ethernet
• C. Bluetooth
• D. WiFi

Answer: (A)

The key idea is choosing a communication technology designed for long distance with minimal power use. LoRa fits this need by operating as a low-power wide-area network (LPWAN). It enables sensors to sleep most of the time and wake only to send small data packets, which greatly extends battery life. Its long-range capability comes from using sub-GHz frequencies and spread-spectrum modulation, giving a high link budget that can reach many kilometers in open areas and still work through buildings.

In practice, sensor nodes often just need to send occasional readings, not stream large data in real time. LoRa’s low data rates are perfectly adequate for this, and the network can cover large areas with relatively few gateways. By contrast, Ethernet requires wired power and physical cabling, Bluetooth is typically limited to short ranges, and WiFi consumes more power and has a shorter reach. So for a low-power, long-range IoT sensor node, LoRa is the most suitable choice.