This Small Business Innovation Research (SBIR) Phase I project will perform research toward developing new behavior characterization methodologies that allow adaptive/cognitive radios to be rapidly introduced into the market improving spectrum utilization and therefore broadband access for all. Expected results include a closed loop test fixture design that dynamically creates realistic RF environments in response to measured adaptive system behavior in a laboratory setting, controlled by an efficient adaptive search algorithm. The complexities involved in simulating realistic dynamic RF environments, sufficient to characterize the behavior of adaptive systems, drive the number of testing cases into the hundreds of millions and test time to many years. The adaptive search problem will be solved using globally optimized experimental alternatives and multi-dimensional splitting levels yielding high confidence results and reasonable test times. The project will combine this efficient search adaptive, rare-event approach with the company's unique dynamic RF environment emulation capabilities to create virtual RF environments that support comprehensive hardware-in-the-loop testing. The intellectual merit of the proposed research lies in combining and improving these unique capabilities in the critical application area of adaptive/cognitive radio testing yielding improved spectrum access.<br/><br/>The broader impact/commercial potential of this project is acceleration of the deployment of adaptive/cognitive radios, offering the prospect of ubiquitous broadband access to the nation's underserved. Lack of universal broadband access, increasingly essential to daily life, is hurting the U.S. The 2012 PCAST report recommends using adaptive/cognitive radio as a solution to meeting these increased demands with existing spectrum, but acknowledges the lack of robust testing capabilities to ensure non-interfering coexistence with incumbent systems. The challenge of deploying adaptive radio technology is that it cannot be fielded without comprehensive testing, and cannot be tested in a live, densely populated RF system environment for fear of interfering with existing spectrum users. This project will develop a system to efficiently validate adaptive radios in the laboratory with field level fidelity. Efficient, high quality testing offers the potential for quicker deployments at significantly reduced costs. The potential uses for adaptive/cognitive radios include commercial fixed and mobile wireless, ad-hoc network, satellite, aviation, DoD, Intel and public safety with potential revenues of hundreds of millions of dollars. This project may benefit millions of underserved individuals and enhance scientific and technological understanding of adaptive, rare-event search techniques as applied to adaptive/cognitive radios.