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Spectrum sensing can be used for determining if opportunistic spectrum use by secondary users is allowable meaning that the usage does not cause harmful interference to the primary user. We investigate an energy based cooperative sensing technique. False alarms refer to determining that the opportunistic spectrum use is not allowable though actually it is allowable. Conventional sensing methods are designed to satisfy a predetermined false alarm PFA corresponding to a certain amount of lost transmission opportunities. Miss probability PM refers to determining the opportunistic spectrum use is allowable though actually it is not allowable. For secondary users in the cognitive radio networks, PM is more important as it is related to the interference caused to the primary user by secondary users. Therefore, we will require that PM is less than some limit. It is difficult to always satisfy a required PM since secondary user should know the received signal level of primary user. We use a new hypothesis model and employ a locally most powerful (LMP) criteria to satisfy the required PM at the decision border. This corresponds to optimizing performance at the worst possible scenario from primary userpsilas viewpoint. A probability density function of the test statistic of the proposed detector is derived analytically. By computer simulation results, we have shown that PM can be satisfied at the border.
Date of Conference: 15-18 Sept. 2008