Energy-Efficient Distributed Spectrum Sensing for Wireless Cognitive Radio Networks

We propose an energy-efficient Distributed Spectrum Sensing (DSS) scheme, called cluster-and-forward based DSS scheme, for our developed two-tier hierarchical cognitive radio network. At each time step, our proposed scheme dynamically clusters the secondary users into multiple groups and selects the Cluster Head (CH) from the secondary users in each group. The selected CHs collect the spectrum sensing results, process the information locally, and send the local fusion results to the fusion center. To reduce the secondary users' power consumption, the selected CHs take turns to be the fusion center, which processes the local spectrum-sensing decision results sent from the other CHs and makes the final spectrum sensing decision. Our scheme is able to achieve the high spectrum sensing accuracy even when the average channel Signal-to-Noise Ratio (SNR) is low. The performance evaluations validate and evaluate our proposed DSS scheme and the clustering method in terms of the spectrum-sensing reliability and the energy efficiency.