Prioritized Random Access with dynamic access barring for RAN overload in 3GPP LTE-A networks

The rapid growth in the number of machine-type communications (MTC) devices causes the radio access network (RAN) to overload when a large number of MTC devices try to access the radio resources in a very short period. A Prioritized Random Access (PRA) scheme is proposed to efficiently solve the RAN overload problem and provide quality-of-service (QoS) for different classes of MTC devices in 3GPP LTE-A networks. This is achieved by pre-allocating random access channel (RACH) resources for different MTC classes with class-dependent backoff procedures and preventing a large number of simultaneous RACH attempts by using dynamic access barring (DAB). Simulation results show that, unlike Extended Access Barring (EAB) and the current LTE-A medium access control (MAC) scheme, the proposed PRA architecture with the DAB scheme guarantees QoS, i.e., high success rate and low access delay, even under the worst case RAN overload in LTE-A networks.