“…Thus, for a cooperative network, the overall probabilities of detection ( Q d ), missed detection ( Q m ), and false alarm ( Q f ) can be expressed as As shown in Figure , there is a possibility that the PU may again reoccupy the given channel even when the CR is transmitting. Thus, we consider 2‐state Markov chain to describe the activity of PU . The duration of PU's busy and idle states is exponentially distributed with mean values α 0 and α 1 under H 0 (PU absent) and H 1 (PU present) hypotheses, respectively, as , where P ( H 0 ) = α 0 /( α 0 + α 1 ) and P ( H 1 ) = α 1 /( α 0 + α 1 ).…”