Improved Cooperative Spectrum Sensing in Cognitive Radio

In this paper, we consider the problem of spectrum sensing in cognitive radio, where unlicensed (secondary) users are allowed to share the vacant frequency bands from the licensed (primary) users. We propose two cooperation protocols to improve the detection probability compared to an existing protocol. In the first protocol, secondary users with higher detection probability constantly act as relays to help those with lower detection probability, while in the second protocol, the help-oriented users choose to relay signals according to the decision made during the first time slot. Analytical studies are provided to demonstrate the enhanced performance of our proposed protocols. Finally, simulation examples are presented to corroborate our analytical results.