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Access control is an effective way to protect the radio access part of Long‐Term Evolution–Advanced (LTE‐A) network from the overload caused by a huge number of Machine‐Type Communication Devices (MTCDs). A class of access control mechanisms is the Access Class Barring (ACB), which regulates the Machine‐to‐Machine (M2M) traffic in accordance with the available Random Access (RA) resources. In this paper, we extend the single power level ACB scheme to a multiple power level method to increase the number of successfully transmitted requests in the case of overload. Our analysis is based on the capture effect in the third step of RA procedure of the LTE‐A system in which one of the transmitted requests by 2 or more co‐tagged MTCDs, MTCDs which use the same preamble in the first step, can be decoded by the evolved–Node B (eNB). We first formulate the power level selection as an optimization problem assuming the perfect capture model without considering MTCDs' energy budget. Then, to take into account MTCDs' energy consumption, the scenario is extended for the signal‐to‐interference ratio–based capture model. In addition, we investigate the advantages of the proposed multiple power level RA method on discriminating the access of MTCDs with different priorities. The numerical results show that using the optimal parameters, the RA throughput can be improved in comparison with the single power level system at the cost of slightly increasing MTCDs' energy consumption and the complexity of RA procedure.

It is expected that the LTE network, which includes the Radio Access Network (RAN) and the Core Network (CN) in 3GPP LTE systems, will be overloaded due to the huge number of Machine-Type Communication (MTC) devices in the near future. Overload in the RAN and CN of the LTE may result in congestion occurrence, resource waste, Quality of Service (QoS) degradation and in the worst-case, it will cause service unavailability. In this paper, we have proposed an adaptive mechanism to manage a large number of MTC devices in both RAN and CN of the LTE network. We use Access Class Barring (ACB) scheme to regulate the MTC traffic according to the congestions level in the RAN and CN. We consider a scenario in which two-priority-based classes of MTC devices are contending for the RAN resources. At first, the overload problem in the RAN is formulated to find the number of allowable contending MTC devices of each class taking into account their required QoS. Then, an active load management policy based on additive increase multiplicative decrease rule is proposed to control the incoming load from multiple cells to the CN. To effectively limit the number of MTC devices in both RAN and CN, in the proposed approach, each Evolved Node B updates the ACB factor upon overload detection in the RAN or CN in an adaptive manner. Simulation results show that the proposed mechanism is able to manage overload in the CN and RAN simultaneously.

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