A hybrid spectrum sensing technique with multiple antenna based on GLRT

Spectrum sensing is the core for any cognitive radio network. Quick detection of the primary user signal allows for higher spectrum efficiency. In this paper, we introduce and implement a new hybrid spectrum sensing technique that is based on combining GLRT with energy detection and utilizing multiple antennas. Our system introduces a compromise between speed and complexity. When the SNR goes below the SNR wall for the low complexity energy detection, our system switches to the more expensive GLRT algorithm. A practical prototype of our system is implemented on the WARP FPGA-based nodes to study its efficiency and complexity. In addition to practical experimental results, we derive theoretical closed form expressions for the probability of false alarm and the probability of detection for our new approach when using multiple antennas at the secondary users. We also compare the multiple antenna approach to the collaborative detection approach.