Network lifetime and energy consumption are major issues in wireless sensor networks while protection of the primary user is the most important activity in a cognitive radio network that necessitates the cognitive radios to detect the primary user signal promptly and accurately. We propose a network architecture that increases lifetime of the network by efficiently consuming energy and guarantees protection of the primary user by enhancing the sensing accuracy of a single radio. The proposed network consists of mobile cognitive radios and infrastructure wireless sensor nodes. The sensor nodes, exploiting their spatial diversity, perform spectrum sensing for the mobile cognitive radios. In the proposed network, sensor nodes laying in the communication range of the cognitive radios form clusters based on their distances. The clusters are regularly updated due to mobility of the cognitive radios and are further divided into disjoint sub-clusters, which are formed by deactivating the redundant sensor nodes. For energy conservation, one of the sub-clusters in a cluster remains active while others are switched to sleep mode. Effectiveness of the proposed network, which is determined in terms of energy consumption, lifetime, and detection error, is shown through simulations.