Which protocol is suitable for IoT devices with restricted power and low data rates over a range of a few kilometres?

• A. Bluetooth
• B. Zigbee
• C. LoRaWAN
• D. 4G

Answer: (C)

For devices that must run on limited power and only need to send small amounts of data over a distance of a few kilometres, a low-power wide-area networking approach is ideal. LoRaWAN is designed exactly for that scenario: it enables battery-powered sensors to transmit infrequently over long distances using very low data rates. It operates in unlicensed sub-GHz bands and uses gateways to collect data from many devices, then forwards it to a central network server. The data rates are lightweight, often in the range of a few hundred bytes up to a few kilobits per second, which suits small payloads and infrequent transmissions. Because devices can sleep most of the time and only wake to send, their batteries can last years, even when covering several kilometers in decent conditions.

In contrast, Bluetooth and Zigbee are built for short-range communication, typically tens to a few hundred meters at most, with higher data rates and more frequent exchanges, which drains power faster when range is needed. 4G is a cellular technology designed for continuous, higher-bandwidth connectivity and larger power consumption, making it unsuitable for ultra-low-power, long-range IoT devices that only need occasional small updates.