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Summary: A major challenge for the development of the upcoming generations of wireless systems is to match the massive expansion of the Internet of things (IoT) applications along with the traditional human communication. Recently, 3rd Generation Partnership Project (3GPP) has suggested the use of LTE‐A to support machine‐to‐machine (M2M) communications to realize the IoT applications. One of the key concerns is the random‐access procedure in LTE‐A, the existence of a massive number of M2M devices results in system overload and congestion in the random‐access channel (RACH). In this paper, we present a new extension to the active barring‐based random‐access scheme. The proposed traffic load access barring (TLAB) RACH access scheme considers the dynamic changes in system traffic when setting the barring information. At the same time, the proposed scheme avoids unnecessary barring of some M2M devices. Our scheme improves the access delay that results from the barring of M2M devices by applying a new rule in the selection of classes to bar and classes to unbar. The simulation results show the superiority of our scheme in terms of success probability, average access delay, and average power consumption. [ABSTRACT FROM AUTHOR]

Adding the cognitive capability to wireless sensor networks allows the sensors to monitor the spectrum and identify the spectrum holes to operate in different frequencies according to the radio environment which result in better spectrum utilization. Spectrum sensing is a main component in any cognitive radio network. In this paper, we propose a new cooperative sensing scheme based on energy detection for cognitive sensor networks which is constrained by the energy limitation of the wireless sensor elements. The proposed scheme minimizes the sensing energy for individual sensor and carefully selects the suitable participant sensors in each cooperative sensing process. This results in maximizing the lifetime of energy-constrained wireless sensor networks. The proposed scheme also takes into consideration the constraints on the detection accuracy. The simulation results show that the proposed scheme prolonged the lifetime of the cognitive network, makes efficient usage of available spectrum by secondary users, and satisfy the target detection performance. [ABSTRACT FROM AUTHOR]