## 2 IoTMADLab and Methodology
### Methodology  
Cities are actively engaging in a digital transformation strategy that positions municipal services as both catalysts and beneficiaries. Interconnection among these services is a must to improve management and enable added value applications. In this work, we propose the combined use of IoT, DTs, and VR to foster collaboration among services.  
* As a first step, we conducted a detailed review of the city's current technological infrastructure and services. This assessment aimed to identify areas where enhancements could be made and potential gaps in technological capabilities, particularly in terms of IoT connectivity. This process included mapping out municipal devices, facilities, and equipment that could benefit from IoT technologies, assessing the existing network and communication systems, and evaluating the degree of digital integration within municipal services. The collaboration with the Digital Office of Madrid City Hall was crucial in defining a starting point for strategic planning and the deployment of IoT solutions aimed at enhancing urban life.
* Following this groundwork, the focus shifted to establishing a common and interoperable framework that would allow for seamless communication between IoT devices and other elements within the city's infrastructure and their respective control centers. An IoT network reference architecture and an open data model was proposed to facilitate clear and effective data interpretation and management across various municipal services, thereby improving service efficiency and quality. The main results from this analysis are described throughout Section 2.3.
* In addition to establishing this framework, the development of a digital twin enhanced with virtual reality technology was initiated. This digital twin is designed to simulate real-world scenarios, test IoT functionalities, and exchange information between physical and virtual components in a controlled environment. The objectives of this model include creating a virtual space for managing and controlling an IoT system equipped with interoperable sensors, enhancing decision-making processes through immersive experiences and data visualization, and conducting thorough tests on IoT communications and services before their widespread implementation in smart urban settings. The main features of such proposal are outlined in Section 3.
* A phase of pilot testing and evaluation was outlined to rigorously assess the practical implementation of IoT technologies and the functionality of the digital twin with virtual reality. This phase took place at the IoTMADLab facilities and is crucial for refining data models, communication protocols, and the synergy between the physical and digital worlds, ensuring that the technological infrastructure and its virtual counterpart operate seamlessly together. This step is vital for confirming the system's effectiveness and readiness for a larger-scale deployment, aiming to establish a robust foundation for real-time data exchange and analysis in the context of Smart Urban Spaces (SUS). SUS are pilot areas within Madrid, and are designed in collaboration with city technicians and awarded service companies and answer to real needs of municipal services. The aim of SUSs is to show city governors, technicians, and citizens the potentials of collaboration cross municipal services leveraging IoT interoperability.