Efficient FPGA-based implementation of a novel dual mode spectrum sensing technique

Cognitive radio networks require an efficient and reliable method of sensing the spectrum. In this paper, we introduce and implement a new dual mode spectrum sensing technique that is based on combining Quickest Detection with Energy Detection. Our dual mode 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 quickest detection based 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. We also numerically compute the SNR wall for our quickest detection based technique.