Software Engineering Institute

Wireless networks for emergency responders and military personnel operating in tactical situations are often assembled without any preexisting infrastructure (i.e., ad hoc) and are subject to changing topology as nodes enter or leave service or move (i.e., are mobile) in the environment. These networks often have lower-than-optimal bandwidth and can see further bandwidth reductions due to disadvantageous topologies and other factors. In addition, needed applications must compete for possibly diminishing bandwidth. As a result, such networks are frequently oversubscribed: they cannot fully meet the quality of service (QoS) expectations of all applications.  

This report provides an overview of approaches for satisfying QoS expectations in ad hoc wireless networks assembled to support high-criticality crisis and tactical scenarios. It illustrates that these approaches are adaptations of approaches used in wired (often fixed) infrastructures where bandwidth is known and interference is not the norm. It documents and provides experimental evidence for the Adaptive QoS (AQoS) approach that allows applications to adapt bandwidth demand to conditions without the need to know, estimate, or predict available bandwidth. AQoS informs applications that oversubscription is occurring, thereby allowing them to continue to operate, albeit at diminished rate or capacity, and meet mission needs.