Multi-hop link adaptation for emergency services narrowband mobile ad-hoc networks

Existing narrowband mobile ad-hoc networks (MANETs) used in disaster search and rescue (SAR) missions and tactical communications are specifically designed to enable robust unicast or broadcast voice communications. The increasing demand for add-on data services such as messaging, file and map transfer etc requires those long-range communication systems to provide higher data rates while maintaining robustness against link disturbances. Link adaptation enables wireless systems to select optimal combinations of transmission parameters based on radio channel conditions. Especially for networks with strong bandwidth limitations as investigated here, the difficulty of increasing overhead emerges, demanding for efficient parameter adaptation. The subject of this paper is the investigation of link adaptation in multi-hop scenarios focusing on highly robust end-to-end communications. Results from Monte Carlo computer simulations show that the combination of relaying and link adaptation can significantly increase the packet delivery ratio while simultaneously improving end-to-end user net throughput.