Optimal soft combination for cooperative spectrum detection in distributed antenna systems

In this paper, we consider cooperative spectrum detection based on energy detection in distributed antenna systems. Soft combination of the observed energies from different cognitive radio users is investigated. Based on the Neyman-Pearson criterion, we obtain an optimal soft combination scheme that maximizes the detection probability for a given false alarm probability. We derive closed-form expressions for the probabilities of detection and false alarm for the optimal soft combination scheme. Finally, we show through numerical results the improvement in cooperative spectrum detection with the optimal soft combination.