Performance Optimization of the MIMO-OFDM Based Adaptive Cognitive Radio System using a Hybrid Channel Access Scheme

Abstract

The cognitive radio is a promising candidate to resolve the issues created due to the spectrum scarcity in wireless communication. The main motive of CR technology is to create communication opportunities by sensing and learning from the external environment thereby improving the spectrum usage efficiency. The integration of the link adaptation, MIMO-OFDM with CR technology gives the utmost performance. In this treatise, we propose the hybrid channel access (interweave-underlay) scheme for the MIMO-OFDM based adaptive CR system. We have investigated the performance of the CR system under a hybrid channel access (interweave-underlay) scheme as well as underlay channel access scheme. We consider the binary stochastic model to reflect the primary user (PU) activities. The performance is evaluated with different channel detection probabilities under perfect as well as imperfect (false alarm) spectrum sensing environment. The result shows the significant improvement in the throughput of the system in proportion with the higher-quality channel detection probability with perfect spectrum sensing. This exploits the hybrid channel access scheme as one of the techniques to optimize the performance of the system. This signifies the importance of the optimum channel sensing and its selection in improving the performance of the system. To show the performance improvement of the CR system using hybrid channel access scheme we have compared it with the performance of the CR system based on the conventional underlay channel access scheme. The proposed scheme can be used to improve the performance of the entire CR network.