One of the main objectives of the TDM project is to create a scalable architecture for the acquisition, integration and analysis of data coming from heterogeneous sources, that is capable of managing information generated by a broad metropolitan area. Some of this data will come from sensors spread over the territory. In order to better manage this devices, the project provides a reference design for a general-purpose platform for sensor-device management and the transmission of the collected measures. This platform is the Edge Gateway.
This document describes the hardware/software architecture of the Edge Gateway and its components devoted to the acquisition and pre-processing of the measurements acquired from the distributed sensors of the project, and their forwarding to the central system for collection, storage and analysis.
The Edge Gateway described here is for general use, and has been specifically designed to be used with other infrastructure based on the FIWARE ecosystem other than the TDM one. It can be used to build OASC-compliant solutions on cloud platforms such as, for example, IoT Amazon AWS, IBM Watson and Microsoft Azure.
In particular, the following reference design is based on hardware platforms easily available on the market and of which all the documentation needed for operation and integration into other products (the data sheet) is freely available (the BeagleBone Black board, described later, for example, is distributed as Open Hardware, i.e. its entire design can be used in the architecture of other devices). Measurement stations used in conjunction with the Edge Gateway are also distributed, as well as finished product, as Open Hardware while the source code of the related firmware is freely available and distributed under Open Source license. The software architecture designed for the Edge Gateway is in turn based on Open Source, standard protocols and example code can be freely used and modified. Communications take place through the MQTT standard protocol, while the message formats are compatible with FIWARE and OASC standards and best practices.
All the software developed is available on GitHub at: https://github.com/tdm-project.
Below is a brief overview of the overall architecture of the project, the architecture developed for the software, the requirements for the hardware platform and the components chosen for the prototype.