Abstract
In this chapter we discussed various spectrum sensing aspects and issues related to TV white space. Special attention has been paid to ongoing TV white space standards i.e. IEEE 802.22 and the IEEE 802.11af. These standards were studied based on their ability to detect primary user (PU) or TV incumbent users and coexistence with other's signals and to avoid transmission in the busy and adjacent channels to ensure proper interference mitigation within the allowable transmitted powers. Throughout the chapter, many TVWS scenarios were studied and elaborated. Sensing is important for devices do not has registered in any database or registered but move with uncoordinated manner and do not have geo-location capabilities. Sensing can be handled via several suboptimal and optimal techniques to extract channel information. Sensing can be used for improving power control and interference cancelations.