## 2 A Portable 5G Platform Architecture for First Responders  
During large-scale emergencies, communications may suffer failure because of network overload or infrastructure damage [5]. Therefore, not only cannot citizens of the affected area reach emergency units and provide them with important initial information about an incident, but FR teams may also face communication problems, as the public network is likely also employed by them. Even if FRs utilize their team-dedicated communication system (e.g., VHF radios), the cross communication between different FR teams, and the central operation control and management of all units, are necessary for successful and efficient mission accomplishment. On top of this, there are cases where FRs have to operate in harsh and dangerous environments, such as low-visibility conditions (because of smoke, dust, low light, etc. ), toxic gas leakage, or collapsed buildings, putting their livesin great danger. Last but not least, when rescue teams locate victims they need to act fast, evaluate the victims' condition, and either offer first aid or transfer them to a hospital. The proposed tentative platform, which utilizes 5G network services and a centralized Command Center (CC), answers to the needs of FR teams. The platform is loaded on a dedicated emergency van, so as to quickly approach an incident area and provide the FRs with the necessary services. The platform is not isolated within the emergency area, but is connected to the central civil protection headquarters for better mission management. The system architecture presented in Figure 1 depicts the key components of the proposed platform, beginning from the First Responders' teams in the field to the PCS, which delivers various on-site Radio Access Technologies (RATs), a 5G core, a virtualized service infrastructure, and a mobile control center with several capabilities, e.g., Slice Manager, NFVO, situational awareness, etc. The communication chain is finalized with the link to the civil protection HQ, which provides the upper-layer management and coordination of the First Responder teams. Specifically, the components are:  
Situational awareness: Situational awareness is the basis for an efficient Common Operational Picture (COP). It provides the required interfaces for command-and-control centers to display images and videos in control rooms using projectors, AR glasses and headsets, and also presents mission specific data. * CC visualization: This provides the means for First Responders to supervise critical infrastructures, increase situational awareness, and orchestrate end-to-end operations. Situational visualization can provide the necessary tools to First Responders for analytical reasoning and intelligent decision making, through insightful visualization of complex and dynamic data. * AR aggregation: This module collects feeds from the AR interfaces of the First Responders in the field. The AR displays various field and unit information from various sensors. The aggregation module helps to monitor the current state of on-field units. * UAV fleet management: The management module coordinates UAV flight plans and operations. Dedicated UAV fleets are considered for the execution of Search and Rescue (SAR) operations. UAVs offer the capabilities for faster location of missing persons within the Regions of Interest (ROIs). Figure 1: Overview of the system architecture. * PCS resource management: The resource management module is the core of the PCS platform, as it contains the orchestration services of the infrastructure. The PCS resource management, comprises of: \(\circ\) Slice Manager: The Slice Manager creates and provides specific network slices for corresponding services required in any given scenario. In the frame of 5G, the Slice Manager acts as the Network Slice Management Functions (NSMF), requesting the provision of resources from the underlying management components of the RAN domain, the WAN, and computing.