RF Sensing in the TV White Space

New wireless systems expected to provide access to broadband networks are being considered for operation in the unused channels of the VHF and UHF TV bands. These new systems will have to avoid interference to TV broadcast operation and one way to achieve this will be by sensing the presence of broadcast operation in the area and change their operating frequency accordingly. This article deals with the feasibility of RF sensing considering the signal levels that need to be detected to protect broadcast operation in the TV bands. It is found that the sensitivity requirement to detect broadcast operation is much more demanding than in other RF sensing applications. An assessment of the level of difficulty of sensing broadcast signals, both TV and wireless microphone signals, is presented along with methods to ease the situation through collaborative sensing, use of wireless microphone beacons or access to incumbent databases.