Before revision:  The analysis framework takes into account buffering of incoming secondary user traffic, parallel and single channel access, as well as prolonged channel observation periods at the first and last stage of sensing. The main results show that when a constraint is given upon the probability of primary user mis-detection , multi-stage sensing is in most cases superior to the single stage sensing counterpart.
After revision:  Our results show that when a constraint is given upon the probability of primary user mis-detection , multi-stage sensing is in most cases superior to the single stage sensing counterpart.