MQTT Protocol

A lightweight messaging protocol designed for IoT applications with low bandwidth and unreliable networks. Often used for RTLS data transmission between devices and servers. Provides publish-subscribe model enabling efficient one-to-many communication. Well-suited for industrial environments with constrained network resources.

Message Queuing Telemetry Transport, lightweight publish-subscribe messaging protocol designed for constrained devices and networks, commonly used for RTLS data distribution. MQTT characteristics: publish-subscribe model (clients publish messages to topics, subscribers receive messages from topics they're interested in), quality of service levels (QoS 0: at-most-once delivery, QoS 1: at-least-once, QoS 2: exactly-once), retained messages (last message on topic retained for new subscribers), and lightweight protocol (minimal overhead, suitable for constrained networks and devices). MQTT in RTLS deployments: (1) Position streaming - RTLS publishing position updates to topics organized by tag ID, zone, or asset type (eg., /rtls/positions/tag-1234, /rtls/zone/assembly-line-1).

MQTT brokers: open-source (Mosquitto, EMQX) and commercial (AWS IoT Core, Azure IoT Hub, HiveMQ).

Typical industrial deployment: MQTT broker co-located with RTLS system or on premises network, RTLS publishing positions at 1-10 Hz to per-tag topics, applications subscribing to topics matching their interests. Performance considerations: broker sizing (typical broker handling 1000s of concurrent connections, 10,000s messages/second), network bandwidth (1000 tags at 1 Hz with 100-byte messages = 100 KB/s = 0.8 Mbps, easily handled by most networks), and message persistence (broker storing recent messages for reliability, typical retention 1 hour to 7 days). MQTT adoption in industrial RTLS growing: 40-50% of new deployments using MQTT for application integration, driven by IoT/IIoT standardization and Industry 4.0 initiatives. MQTT enables clean integration architecture: RTLS publishes to broker, multiple applications subscribe independently, adding new applications or removing old doesn't require RTLS system changes.