Emergency Trunk Reservation Control Using Waiting Queue for Accommodating More General Calls

A huge number of calls are generated as a means of confirming the safety of others or communicating with the police, fire department, etc. in an emergency, such as an earthquake or lire. Therefore, phone congestion occurs and it is difficult to connect all calls over a local telephone network. As countermeasures against congestion, to increase the number of calls accommodated in an emergency over a circuit-switched network. the trunk reservation control method for reserving certain lines exclusively for priority calls used by public institutions and the holding time control method for general calls have been proposed. These effectiveness of these methods has been demonstrated in the past. However, when using these controls, the call blocking probability for general calls is high, meaning it is necessary to further reduce call loss probability. In this paper, we propose a trunk reservation control method that facilitates call wailing to reduce call loss probability. In comparison to the conventional method without a waiting queue, the proposed method decreases call loss probability for general calls while maintaining a low call loss probability for emergency calls.