Feasibility of voice service in cognitive networks over the TV spectrum

We consider a cognitive network where the secondary users generate voice traffic and search for sharing opportunities over the TV spectrum. From the cognitive network perspective the TV bands can be idle, occupied or acceptable. A band is classified as acceptable when the TV signal is present but the secondary users can still share the band by lowering their transmission power. Therefore, the acceptable bands offer a lower rate transmission opportunity compared to the idle bands, while the occupied bands cannot be utilized at all for secondary transmission. When most of the measured bands are detected to be occupied, there might not be enough capacity to serve all the secondary users' calls. In this paper we identify the number of measured TV bands so that with a high probability all the secondary users are scheduled on some of the measured bands. The results of this paper are promising. It is shown that the number of secondary users sharing the spectrum grows much quicker than the number of TV bands required to be measured.