Channel Coding for Cooperative Spectrum Sensing Under Imperfect Reporting Channels

In cognitive radio (CR), cooperative spectrum sensing (CSS) is used to overcome the effects of fading, shadowing, and hidden node problems. The CSS improves the detection performance by utilizing the spatial diversity among the cooperating secondary users (CSUs). In centralized CSS, the CSUs share their information with the fusion center (FC), who takes the final decision. However, CSUs share their information using wireless channels, which are prone to channel impairments. Hence, the channels between CSUs and FC may not be perfect. In this work, the cooperative spectrum sensing under an imperfect reporting channel is studied. First, the performance of the energy detection based CSS is analyzed under imperfect reporting channels. Then, an algorithm based on channel code, specifically repetition code, is proposed for performance improvement under an imperfect reporting channel. It is demonstrated that the performance can be significantly improved using the proposed algorithm, and by adequately adjusting the parameters, the effects of reporting channel errors can be completely removed.