Abstract: Different from traditional wireless networks, in dynamic spectrum access networks, primary users have privilege to use the spectrum and hence the connectivity of secondary user network is affected by the distribution and activity of the primary users. Based on continuum percolation theory, this paper proved that secondary users can form the percolated network when there were less primary users or the load of primary users was light.On the other hand, secondary user network couldnot be percolated when there were many primary users and the load was heavy. The necessary condition of the existence of percolated secondary user network was derived when the primary users and secondary users shared one channel. All above conclusions arc examined by extensive simulations.

Key words: Dynamic spectrum access, Connectivity, Continuum percolation