Protection of primary users in areas where cognitive radio is deployed

Cognitive radio systems and `whitespace´ devices are radio systems that can use unoccupied spectrum to establish communications links. These systems, when properly implemented, would deliver an increase in the utility of the spectrum, thus increasing service delivery, without causing harmful interference to existing licensed systems. Spectrum may be unoccupied either temporally or geographically. In either case we refer to this fortuitous access to the spectrum as `auxiliary access´. To permit such access in otherwise occupied spectrum a system of protection factors must be developed which ensure the protection of the `primary´ system while still realistically permitting operation of the dynamic or whitespace system. This paper proposes a set of transmission levels that would enable the use of cognitive devices in suitable bands.