Combined Access Barring for Energy and Delay Constrained Machine Type Communications

In this paper, we present a novel scheme to improve the performance of random access process for energy and delay constrained machine type communication (MTC) devices in long term evolution (LTE). Staggering number of MTC devices and their bursty nature of traffic call for the sophisticated schemes to control the transmission of preambles, associated with random access procedure. Access delay is an important metric for delay- sensitive MTC services while energy constrained MTC devices expect little collision in the random access procedure. Access class barring (ACB) yields less access delay at the cost of unavoidable collisions. Whereas, extended access barring (EAB) brings higher energy efficiency baking on less collision probability with increased access delay. By combining the advantages of both ACB and EAB, we propose a novel scheme that can balance the access delay and the collision probability. Extensive computer simulations verify the effectiveness of the proposed scheme.