## 7 Conclusions  
In this paper, we have presented the design and implementation of a field deployable communication system for volunteer USAR teams. The system offers local wireless connectivity, exploiting diverse technologies and connectivity to the UCC or the internet through multiple interfaces. The proposed system has been evaluated through multiple tests and was able to cope successfully with the network traffic generated by the various devices used in the field. 802.11 ax played an essential role in delivering a competent system that was positively reviewed by the end users present at those tests, who were able, in a short time, to learn how to operate and deploy it on their own. This is due to the way the system boots up, having all of its components trying to connect to the central communication node (which has a static predefined address) via network layer three. The central communication node hosts the services that manage the rest of the system and bring it up to operational status, delivering a system that works with the \"push of a button\". Additionally, the usage of network layer three as the interconnection method of the system's submodules means  
Figure 11: (a) The field communication system deployed during a full-scale exercise. The WiFi AP utilizes a 4 \(\times\) 4 MIMO directional antenna in combination with four omnidirectional antennas. (b) RSSI heat map overlaid on the satellite image of the map of the area where the full-scale exercise took place. The antenna mast was set up at the location marked with the red dot. that the system can be easily updated with new hardware by Information Technology (IT) personnel, already available within most organizations, keeping the system relevant for a longer time period with minimum effort. The system can be further improved by exploiting recent advances in the field of communication satellites which have made available new services that do not suffer from the traditional shortcomings of satellite-based communications. In particular, the long distance that the electromagnetic waves had to travel to reach the satellite led to latency while the small number of satellites in the constellations severely limited the total available bandwidth and, consequently, the downlink and uplink transmission speed offered to the users. Using mass-produced low earth orbit satellites, newer services, such as Starlink, promise low latency, high bandwidth communications across the globe. Our system can easily accommodate the replacement of the current satellite communication terminal with one of newer technologies due to its modular architecture. When the constellations that are currently being deployed reach the intended size and offer worldwide coverage, the inclusion of a suitable satellite terminal in our solution will further enhance the resilience of the field communication system. With our work, we tried to bridge the gap between academic research and real-world systems to provide USAR teams with tools that will increase their productivity. After the first 72 h following a disaster, sometimes called the golden 72 h, the chances of finding alive victims drop drastically. Any tool that can increase the productivity of the first responders means more people are rescued. This motivated us to address practical problems encountered during the USAR process. We have worked to deliver a system with sufficient TRL to be used in the field to address the communication needs of a volunteer USAR team, and we will continue to refine our system with the hope of delivering a tool that will eventually be used in a real operation. Finally, given that there is a measurable performance difference between the various generations of WiFi standards, a new, more extended measurement campaign over different terrains and including more parameter variations can be part of future work to better qualify the coverage area and associated performance.