Performance evaluation of priority control scheme for shortest reservation calls under disaster congestion

Abstract

When disasters such as earthquakes occur, telephone traffic to the disaster area increases rapidly, to confirm the safety of residents, leading to telephone network congestion. The existing congestion control for telephone networks consists of call regulation control, through which call demands at the subscriber network switches or cellular phones are suppressed. This results in a drastic decrease in the call completion rate. Disaster emergency message dial services do not meet users’ needs either to confirm the safety of people at the disaster area or to speak with them directly. In this paper, we propose a priority control scheme based on call reservations and evaluate its transient characteristics. We also propose an improved scheme to shorten the desired holding time by a fixed rate, when the number of waiting reservation calls exceeds a threshold, which can suppress the divergence of the number of reservations. We evaluated the average waiting time and threshold excess rate characteristics, and confirmed that the proposed scheme can provide stabilization.