For spectrum sensing, primarily three signal processing techniques are designed i.e. matched filter energy detection and cyclo-stationary feature detection technique. Matched filtering is best. However it requires detailed knowledge of primary signaling. But when no knowledge about the primary user signal is assumed, an energy detector is most favorable. Also IEEE 802.22 will provide for spectrum sensing via energy detection. In this paper, the authors are dealing with different types of spectrum sensing is a radio process for determining whether a signal is present across a specified RF bandwidth.