MQTT Protocol: How It Works in IoT & NB-IoT

When it comes to IoT, communication is everything. Devices need a reliable way to send and receive data — whether it’s a temperature reading from a sensor or a control signal from an application. One of the most popular protocols for this is MQTT.

What is MQTT?, MQTT on NB-IoT Challenges, MQTT vs Alternatives.

MQTT is a lightweight messaging protocol based on a publish/subscribe model. Instead of devices communicating directly, they connect to a central broker that manages data exchange.

• Publishers send data on a topic (e.g., /Device/Sensor1/Temperature).
• Subscribers receive updates only for the topics they care about.
• Payloads can be simple values, JSON, XML, or binary.

MQTT runs on TCP and can be secured with TLS. It also supports features like Quality of Service (QoS) levels, session persistence, and flexible data structuring.

Relevance to NB-IoT

Despite being “lightweight,” MQTT comes with challenges on NB-IoT:

• TCP overhead increases latency.
• Keep-alive messages drain battery.
• TLS handshakes consume bandwidth and power.

This makes MQTT suitable for mains-powered or low-volume NB-IoT devices, but less ideal for battery-powered sensors.

Common Use Cases

• Smart homes (appliances, lighting, HVAC).
• Industrial IoT (IIoT) applications.
• Cloud integration where ecosystem support is critical.
  
  

Key Takeaways

MQTT’s strength lies in its ecosystem and familiarity. It persists in IoT even where technically suboptimal, because it’s easy to implement and well-supported. But for battery-constrained NB-IoT, alternatives like CoAP or LwM2M are more efficient.