Integrating Queuing Regime into Cognitive Radio Channel Aggregation Policies: A Performance Evaluation

Channel aggregation (CA) is one of the newest concept which cognitive radio network is bringing to bear for the smooth role out of fifth/next generation wireless networks. This is the combining of several unused primary user spectrum holes into a logic usable channel. However, several of these strategies have been investigated considering the varying nature of wireless link and adaptive modulation and coding (AMC). Examples are the instant blocking strategy (IBS) and readjustment based strategy (RBS). This paper develops and compares two CA policies with queue, which are the IBS with queue (IBS + Q), and the RBS with queue (RBS+Q). This is in furtherance of previous proposed work. The aim is to identifying the impact of a queuing regime on the performance of the secondary network such that any secondary user (SU) that has not completed its service, as an alternative to dropping or forcibly terminating the service, it is queued in order to get another opportunity to access the primary user (PU) channels. The performance is evaluated through a simulation framework. The results validate that with a welldesigned queuing regime, capacity, access and other metrics can be improved with significant reduction in blocking and forced termination probabilities respectively. Index Terms AMC, channel aggregation (CA), cognitive radio networks (CRN), queue, signal-to-noise ratio (SNR).