Spatio-frequency domain opportunistic access in CR-MIMO system based on primary transmission mode information

An opportunistic spatio-frequency access (OSFA) strategy for CR-MIMO system was designed.When spectrum holes exist,cognitive service was implemented applying overlay approach.While there was no idle spectrum available,primary transmission mode information (PTMI) and inter-system interference channel information were exploited.And cognitive service was implemented using underlay approach.The method utilizes both spatial correlation and eigenmode transmission gain in spatial resource quality aluation.Consequently,selection diversity of both authorized channel and cognitive eigenmode was achieved.Moreover,PTMI based signal processing reduced the antenna requirement for cognitive system as well as the power loss of cognitive signal.Simulation results indicate that the proposed method could achieve significant improvement of cognitive service and near-optimal cognitive throughput on the premise that no interference is imposed on the primary.