Abstract: In order to take advantage of the asynchronous sensing information, alleviate the sensing overhead of secondary users (SUs) and improve the detection performance, a sensor node-assisted asynchronous cooperative spectrum sensing (SN-ACSS) scheme for cognitive radio (CR) network (CRN) was proposed. In SN-ACSS, each SU is surrounded by sensor nodes (SNs), which asynchronously make hard decisions and soft decisions based on the Bayesian fusion rule instead of the SU. The SU combines these soft decisions and makes the local soft decision. Finally, the fusion center (FC) fuses the local soft decisions transmitted from SUs with different weight coefficients to attain the final soft decision. Besides, the impact of the statistics of licensed band occupancy on detection performance and the fact that different SNs have different sensing contributions are also considered in SN-ACSS scheme. Numerical results show that compared with the conventional synchronous cooperative spectrum sensing (SCSS) and the existing ACSS schemes, SN-ACSS algorithm achieves a better detection performance and lower cost with the same number of SNs.

Key words: cognitive radio, asynchronous cooperative spectrum sensing, Bayesian fusion rule, ON-OFF model, soft decision