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

With its capability for long range and good penetration, UHF is a popular wireless band. Because of this, frequency allocations in UHF are typically small, on the order of tens of kHz. At the same time, there is an increasing popularity of aerial platforms, such as UAVs, containing a variety of imaging systems. So, while there may be numerous UAVs in a particular region of interest, there is no current mechanism to send this high-rate data directly to ground forces. We propose to develop a wireless communication system that is able to transmit high-rate imagery (> 1 Mbps) over a traditional narrow-band voice channel (25 kHz). Our proposed approach is based on a spatial multiplexing architecture applied to MIMO antenna arrays. The technique works well in non line of sight environments, such as those found between low-flying UAVs and urban ground forces. Taking into account practical operational conditions, where either friendly or hostile forces may employ jamming, the architecture can mitigate jamming signals that are significantly higher power than the signal of interest. In addition to algorithmic aspects, we also address practical considerations of the antenna array, the RF and baseband implementation, as well as candidate sensor payloads.