Gateway-assisted two-stage radio access for machine type communication in LTE-Advanced network

In Long Term Evolution-Advanced (LTE-A) network, Machine Type Communication (MTC) provides random access-based communication for automation applications. One of the most critical issues in MTC is the emergence of large number of MTC devices which may send requests to the base station simultaneously, and incur severe collision at the base station. When collision occurs, the data delivery fails, and the message delay accumulates. In this paper, we propose a gateway-assisted two-stage (GATS) radio access scheme to alleviate collision for delay-tolerant MTC applications. In GATS, MTC devices are divided into several groups, where random access in each group (as the first stage) is controlled by a device called MTC gateway. Collision of random access to the base station (as the second stage) is then effectively alleviated. Then we propose analytical model and simulation model to investigate the performance of GATS in terms of utilization of random access slots, access success probability and average message delay. Simulation results show that, by sacrificing a little message delay, GATS scheme significantly improves access success probability. Besides, when the group number increases, the delay becomes smaller.