Three analytical approaches to combine ACB scheme and timing advance information for stationary MTC devices

Abstract

Recently, long-term evolution (LTE) technology has been considered as a promising solution for realisation of ubiquitous machine-to-machine communications. However, this solution faces massive access of machine-type communication (MTC) devices as one of the most important challenges. In this study, access class barring (ACB) scheme and timing advance information (TAI) are combined to manage massive access of stationary MTC devices to LTE networks. Although, using TAI can help contention alleviation, it can destroy fairness among devices. So, the aim of this study is maximisation of number of successfully served devices, while fairness is achieved too. Three analytical approaches are proposed. In the first scheme, the probability of success for the most serious contending devices is maximised. In the second and third schemes, one ACB factor is allocated to each annulus. In the second scheme, the expected number of successful devices in one random access (RA) slot has been maximised and in the third scheme fairness has been established among devices. Furthermore, two methods are introduced that estimate the number of backlogged devices in every RA slot. The performances of three schemes and results of a recent attempt in this field are compared with each other. Through simulations, it has been shown that the third scheme represents the best performance in terms of fairness and number of slots required to serve total MTC devices.