With the advent of new high data rate wireless applications, as well as growth of existing wireless services, demand for additional spectrum is rapidly increasing. Existing "command-and-control" spectrum allocations defined by government regulatory authorities, such as federal communications commission (FCC), prohibit unlicensed access to licensed spectrum, constraining them instead to several heavily populated, interference-prone frequency bands. Though several report shows that still the spectrum is not utilized efficiently across time and frequency. To use spectrum efficiently, a new...