On the Origins of Heavy Tailed Delay in Dynamic Spectrum Access Networks
Dynamic Spectrum Access (DSA) allows Secondary Users (SUs) to opportunistically transmit when the channels belonging to Primary Users (PUs) are idle. This paper provides an asymptotic analysis of the transmission delay experienced by SUs for DSA networks. It is shown that DSA induces only light-tailed delay as long as both the busy time of PU channels and the message size of SUs are light-tailed. On the contrary, if either the busy time or the message size is heavy tailed, then the SUs' transmission delay is heavy tailed. Moreover, the impact of spectrum mobility and multi-radio diversity on the delay performance of SUs is studied.