A study on cooperative detection scheme based on combination for cognitive radio systems

In this paper, we propose a new cooperative detection scheme which provides an individual detection for each secondary node unlike the conventional one gives a common decision in the secondary network. The common decision by the conventional scheme may result in degraded frequency efficiency because some secondary nodes can transmit the signal without interference to the primary system even if the decision denies the transmission by the nodes. Thus, the decision is correct and is incorrect for some nodes. At each secondary node, we give tentative decisions by combining observed signals and provide a final decision by combining the tentative decisions based on a logical fusion method. The proposed method is simple and independence of parameters. By computer simulations, we evaluate detection performances of the proposed method and show that the proposed method outperforms the conventional one in terms of detection error probabilities.