  Cognitive radio transceiver can opportunistically access the underutilized
spectrum resource of primary systems for new wireless services. With interleave
implementation, the secondary transmission may be interrupted by the primary
user's transmission. To facilitate the delay analysis of such secondary
transmission for a fixed-size secondary packet, we study the resulting extended
delivery time that includes both transmission time and waiting time. In
particular, we derive the exact distribution function of extended delivery time
of secondary transmission for both continuous sensing and periodic sensing
cases. Selected numerical and simulation results are presented for illustrating
the mathematical formulation. Finally, we consider a generalized M/G/1 queue
set-up at the secondary user and formulate the closed-form expressions for the
expected delay with Poisson traffic. The analytical results will greatly
facilitate the design of the secondary system for particular target
application.
