Seamless Non-Line-Of-Sight Communications for Urban Warfare

With the continued proliferation of airborne assets and associated sensors, the Air Force of today offers the capability of providing new levels of situational awareness. The possibility of having measurements, such as imaging, delivered in real-time to a broad range of forward deployed units as well as commanders, fits well into the vision of network centric warfare (NCW). At the same time, these new demands on the amount of information exchange often exceed the capabilities of existing radio systems. One promising technology is the use of space time coding (STC). While STC is a mature technology that has demonstrated tremendous capacity gains over classical narrowband systems, its use for military operations presents numerous challenges. Our approach addresses issues, such as mobility and jamming, which are present in military environments. To address mobility, we propose the use of quasi-orthogonal space time block codes (OSTBCs) that do not require channel state information (CSI) to be available at the transmitter. Additionally, our receiver design jointly performs channel estimation and detection. This provides increased robustness because the algorithm can continuously demodulate the signal during quickly changing channel conditions and/or in the presence of jamming.