## 1 Introduction  
Every year, millions of people are affected by disasters. In 2021 alone, the Emergency Event Database (EM-DAT) recorded 432 disastrous events related to natural hazards worldwide. Overall, these accounted for 10,492 deaths, affected 101.8 million people, and caused approximately 252.1 billion USD of economic losses [1]. To alleviate the impact of disasters, governments invest in prevention and maintain relief bodies. Prevention is achieved by legislation, such as earthquake codes, and public works, such as tsunami walls or firebreak zones. Disaster relief can include capabilities for damage assessment, coordination, specialized personnel at Urban Search And Rescue (USAR), civil protection, and even armed forces. Despite these efforts to reduce the impact of disasters, their scale and ferocity can leave entire countries in disarray. Countries experiencing such events receive additional assistance from the international community through Intergovernmental Organizations (IGOs) and Non-Government Organizations (NGOs). NGOs provide not only material support but also assistance through volunteer USAR teams formed by citizens motivated into action to assist their fellow citizens in times of need. Just like their government-sponsored counterparts, volunteer USAR teams require equipment to cope with the challenges presented during relief missions. The equipment used ranges from ropes to listening devices (vibration or seismic detectors, also known as geophones), search cameras to view victims, radar movement detectors, and even K9 dogs, drones, or robots. In addition, there is the need for communication and IT infrastructure to support other tools or relay information to a USAR Coordination Cell (UCC) [2] where information is gathered and the overall effort of rescue teams is coordinated. In the past, the provision of voice communication over VHF/UHF radios was sufficient, but today there is the need to transfer images, videos, or access cloud services. Moreover, it is not uncommon for command and control software to be utilized to provide a common operational picture. For this to work, at least the team leaders and, ideally, the various assets deployed in the field must be able to exchange information with the UCC. Consequently, there is the need for connectivity which can be divided into two categories: local wireless connectivity and backhaul connectivity towards the UCC and the internet. Local wireless connectivity is needed both at medium (<150 m) and at long ranges (<1000 m) to support different types of devices. Medium-range wireless communication targets devices such as tablets, cell phones, or inter-component communication for a single tool, such as data transmission from a drone tethering station to a video server. Long-range communication supports wearable devices used by the First Responders to track them or monitor their vitals with the aim of protecting their well-being and safety. Backhaul connectivity towards the UCC and the internet is used to transfer the information gathered by the local wireless network to the UCC or provide access to remote services, on which an ever-growing percentage of devices rely. Besides the need to provide two types of connectivity, a field communication system that can be used by volunteer USAR teams cannot use Commercial Off The Self (COTS) products that operate in licensed parts of the spectrum. Instead, hardware that can be used freely by any individual has to be selected. Additionally, a communication solution destined to be used in times of emergency should be self-sufficient. Reliance on civil infrastructure, such as the power grid or cellular networks, has to be avoided. The overall size and weight of the any proposed solution should permit easy transfer and deployment. A more detailed analysis of the user requirements of such a system can be found in our previous work in [3].