Proposed STBC with Alamouti scheme in cognitive radio networks

Cognitive radio is an intelligent spectrum sharing technology to improve the spectrum utilization. One of the major functional blocks of cognitive radio is spectrum sensing which detects spectrum holes and estimates their power contents. The cooperative operation can improve the sensing performance of cognitive radio networks. Combination multiple cognitive users' local detection results and making accurate judgment are essential to improve cooperative gain. In this paper, the performance analysis of one bit hard combination using AND rule for cooperative spectrum sensing over imperfect sensing and reporting channels will be made which is not clarified until now. Simulation results show that the sensing performance can be significantly degraded. To reduce this performance loss, we propose Space Time Block Coding (STBC) with Alamouti code. The probability of detection is improved by 10% at 30% of a false alarm probability using Alamouti code.