Abstract
This paper reviews the current trends and challenges regarding the use of “white space” in wireless communications, which is a freauency spectrum unused at a certain time and location. Regulatory issues related to the use of white space in the TV broadcast band (TV white space: TVWS) and standardization activities related to wireless communications in TVWS are described. the technical elements of cognitive radio incorporated in IEEE 802.22, which is the first IEEE standard for the use of TVWS, are reviewed. Finally, future problems to be solved to realize better use of the white space spectrum are also discussed.
