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Nowadays telecommunication infrastructure (including mobile base stations and wireless access points) enables reliable communication in a broad range of settings. People rely on this infrastructure not only for casual communication but also during emergency situations, when communication is most vital. In many such circumstances, however, communication infrastructure fails to work or gets destroyed altogether. Consequently, communications are disrupted with both mobile phones, and landlines becoming non-operational, leaving many people isolated and helpless, (Kwasinski, 2012; Corley, 2010).
On the other hand, public safety networks are purposefully deployed to provide emergency support to victims and crew members by partially restoring communications in a local or regional vicinity, (Abusch-Magder, 2007). Arguably, mobile ad hoc networks are a good candidate for these situations as they meet many of the needs that arise (Mase, 2011; George, 2010; Chen, 2010; Suzuki 2012). They offer quick and spontaneous setup, adequate life expectancy of the network, interoperability, tariff-free operation, dynamic network coverage, support for heterogeneous traffic services, ease of use and low equipment cost (Lakshmi, 2012; Reina, 2013). Currently only organized governmental departments and agencies, and some business have plans to support public safety mobile ad-hoc networks. Government agencies including police, firefighters, civil defense and medical units possess specialized walkie-talkie style equipment to operate TETRA (Terrestrial Trunked Radio) for inter-communication (ETSI EP-TETRA, 1997). Evidently, civilians do not have access to such equipment and instead are increasingly using smartphones for all their needs (3GPP, 2012). Fortunately, these powerful devices have the communication and processing capabilities to support adhoc communication in case of emergencies and allow data traffic to propagate across the network in a multi-hop fashion (Koumidis, 2015). To date, numerous such approaches have been proposed and developed for casual communication but only few take into consideration the particular characteristics of an emergency scenario. On such characteristic is that in emergency situations the receiving part of a help request is most of the times unknown since survivors do not know who to reach for help. Also the responders to an emergency call may change dynamically so the receiving end of help requests may change frequently. Moreover, since no time bounds exist during emergencies, battery consumption must be thriftily used to extend network lifetime.