Queuing method in combined channel aggregation and fragmentation strategy for dynamic spectrum access

To achieve highly efficient and flexible spectrum sharing in cognitive radio networks, we proposed a queuing method in combined channel aggregation and fragmentation (CAF) strategy for dynamic spectrum access (DSA). We derived the balance equation and evaluated various system performance metrics including blocking probability, dropping probability, spectrum utilization, throughput and mean queuing time by a continuous time Markov chain (CTMC) model. Numerical results show that this CAF with queuing strategy greatly lowers the dropping probability without obviously impacting the blocking probability, and slightly increases the spectrum utilization and throughput of the secondary network compared with the non-queuing case. Moreover, by tuning the bandwidth requirement of each secondary user, different system performance can be achieved.