Adaptive Access Class Barring for Machine-Type Communications in LTE-A

In LTE-A networks, massive MTC (Machine-Type Communication) devices may request RACH (Random Access Channel) access simultaneously. The concurrent requests bring about the congestion of the channel. To solve the problem, 3GPP has adopted overload resolution mechanisms like ACB (Access Class Barring) and EAB (Extended Access Barring). In the mechanisms, barring parameters need to be set dynamically to reshape the access intensity of MTC devices. This paper proposes how to determine a barring parameter in ACB mechanism adaptively as an overload resolution mechanism. The experimental results show that our mechanism improves system performances including access success probability, collision probability, and access delay.