Asynchronous Dynamic Spectrum Access
Synchronization among Primary Users (PUs) and Secondary Users (SUs) is either explicitly or implicitly assumed in the literature to allow reliable Dynamic Spectrum Access (DSA) and Cognitive Radio (CR) networking. However, in realistic DSA that supports ad-hoc transmissions, perfect synchronization is not attainable in the absence of a centralized control mechanism, particularly among SUs. Current efforts either ideally assume perfect synchronization among PUs and SUs or consider medium access that does not require network synchronization based on a single SU. In this paper, the authors propose an implementable asynchronous DSA scheme by practically considering the timing misalignment with multiple SUs competing for the spectrum opportunity.