Technical Configuration of Portable/Mobile TV White Space Devices: A Conceptual View

As is known, to eliminate interference, the frequency reuse approach is followed in Digital TV planning similar to cellular network, avoiding the use of the same channel in two neighboring allotments. There are large areas where a certain group of TV channels are deliberately not used. They are called white spaces in TV spectrum (TVWS). Considering the great economical value of TV spectrum, it was proposed to use TVWS for low-power wireless networking on non-interfering (secondary) basis with the licensed (primary) DTV service. At the same time, restrictions imposed on white space devices (WSDs) to protect primary users should not devaluate spectrum for secondary use. The lack of knowledge about the locations of primary receivers as well as unreliability of estimation of the aggregate interference impact caused by the large number of secondary devices accessing the spectrum are reported to be among the key challenges for the use of TVWS. In our view, parameters for protection of primary system should be based on the determination of minimum separation distance, observance of which at a certain area could be ensured. The required shadow margin as well as multi-user margin will be calculated for such minimum safety range. To reuse spectrum efficiently mobile/portable WSDs should support dynamic power control ability which has to be a key role of sensing and operate with the lower power where TV signal is weak. Except of providing WSDs with a list of available channels, the geolocation database should contain recommended parameters for path loss calculations as well as minimum distances which could be ensured for a certain inhabited locality.