Application of MQTT Based Message Brokers for IoT Devices Within Smart City Solutions

The advent of the Internet of Things (IoT) devices and platforms opened several new services and application possibilities within Smart City solutions. Their successful implementation is reflected in operational efficiency improvements as well as the quality of the provided government services. Such solutions also provide a way to share information with the public. The solutions assume the utilization of various IoT devices to collect and analyze data. Very important decisions in the implementations of such systems are related to the technology stack and the choice of data transfer system during communication. Different communication protocols are used in the application layer, and one of them is the lightweight MQTT message protocol, with the corresponding message broker. We propose the structure of an entire Smart City system solution. MQTT protocol is used for communication, and, data is visualized on an interactive map. Benchmark tests were done to examine the performance of the used message brokers. We show that the MQTT message protocol is a suitable solution for the proposed application. Also, a dedicated message broker service is the most suitable solution for routing information messages.