Subchannel allocation for dynamic spectrum access in underlay OFDMA system

Dynamic spectrum access has recently attracted interest for better utilisation of reserved frequency bands. Quality of service issues have to be addressed in these systems in the presence of multipath fading. This is especially the case when the number of users in the secondary system grow. Multi-user resource scheduling is critical to mitigate the issue. In this work, we consider scheduling for dynamic spectrum access in a combination of underlay and overlay frequency bands. A subchannel allocation algorithm is proposed for fixed data rate provisioning. Numerical results are shown for performance of the algorithm for arbitrary number of users. Measured channels are used for the simulations to validate real-time application. The results show that the performance gain with joint scheduling in overlay and underlay bands is significant.