Placement of UAVs as Communication Relays Aiding Mobile Ad Hoc Wireless Networks

Unmanned aerial vehicles (UAVs) have been used for surveillance and reconnaaissance operations. Such communications enabled platforms can also be effectively utilized to enhance the communications transport capabilitites of a mobile ad hoc wireless network. When properly embedded into the architecture of a communications network, the resultirng UAV aided terrestrial network architecture is expended into a multi-layered hierarchical network structure. The UAV aided network can provide for transport of flows that span longer distances, yield better reliability, higher mobility based robustness and upgraded throughput capacity. We have recently proposed the `robust throughput' and `robust throughput capacity' measures to characterize the capability of a mobile ad hoc wireless network to provide for robust and survivable transport of flows. Robust service is critically required for supporting applications that involve flow transactions that must not, with high probability, be transported along routes that are prematurely interrupted. To enhance the robust throughput performance of mobile ad hoc wireless networks, we present in this paper a method and algorithm that are used to place relay nodes, such as UAVs, in locations that efficiently serve to support the robustness and capacity requirements of the underlying mobile ad hoc wireless network system, and to compute the optitmal (flow admission oriented) regulation and distribution of traffic flow classes across terrestrial and UAV based routes. Our schemes are used to determine effective 3-D coordinates for placing a UAV relay node to provide for such joint performance upgrade.