Using simulation to evaluate LTE load control for priority users

Disasters can cause extraordinary service demand by the public. It is imperative that services supporting disaster response perform with minimal degradation during such events. In order to provide adequate service to special users such as first responders, priority treatment mechanisms have to be developed. Priority treatments have been incorporated for earlier wireless technologies, but have to be established on Long-term Evolution (LTE) / 4G. One of the proposed priority-treatment concepts is Access Class Barring (ACB), which will shed traffic from public users in response to extreme overloads, resulting in priority for special users. However, the degree to which ACB would improve voice call completion is unknown. A discrete-event simulation was performed to model extreme overload situations and predict the performance of ACB under various configurations. The simulation study found that ACB could drastically improve the priority call completion probability in the most extreme overloads while maintaining performance for public traffic.