Advanced access class barring for massive iot deployment over lte-a networks

LTE-A is one of the latest generations of communication mobile systems that should support, in addition to traditional voice and data communication services, new communication paradigms, such as the Internet of Things (IoT) and machine-to-machine (M2M) services, which implement communication between machine-type communication devices (MTCs) in a fully automated manner, without human intervention or with minimal human intervention. We will use the term User Equipment (UE) to designate these devices. With the IoT, the network is subject to recurrent congestions, due to an increased solicitation of the uplink channel, during radio access. Idle terminals must compete in a process called Random Access Channel (RACH) to access the network. The collision that causes congestion occurs during this process and it has a negative impact on the quality of service (QoS). The Third Generation Partnership Project (3GPP) has proposed for this purpose, among others solutions, the Access Class Barring (ACB) to alleviate the problem. With the ACB, terminals are divided into classes. An access probability P_acb (ac-barring factor) is broadcast by the base station toward the different classes of terminals. The UEs in turn generate a random number q, and are allowed to pass the RACH process only in the case where q ≤ P_acb. Otherwise, it must wait for tbarring (called barring time) before resuming the process. In this paper we propose the Advanced ACB (A-ACB) for significantly reducing the collisions responsible of the congestion problem in M2M communications for IoT. The originality and the contribution of this paper reside in the fact that our method combines congestion detection method that we have proposed in (Mahamadou, 2018), which consists of determining the threshold of resource utilization (Rlimit) and the amount of used resources (Rused), in order to activate the basic ACB if the Rused reaches the Rlimit. The simulations results show that the proposed A-ACB gives much better results compared to basic ACB. Furthermore, the proposed scheme is less complex and easy to implement in the LTE-A networks. Also, it does not require large investments for network operators.