VoIP call admission control scheme considering VoIP on-off patterns

VolP service has rapidly been increasing in popularity recently, since it can provide conversational service with low price and high voice quality by using packet networks. During a voice call, human speech consists of on-periods and off-periods. VoIP service generates fixed-size packets periodically in on-periods. In off-periods, a user occupies the channel but does not transmit voice information. This can result in the link utilization being deteriorated. We propose a new call admission control scheme to achieve high link utilization and to satisfy the Quality of Service (QoS) of all users in networks. CAC is an important factor to determine the channel efficiency and the QoS of VoIP services. The purpose of CAC is to make decisions for whether to accept or reject a new call. For analysis, we investigate the on-off patterns of VoIP traffic from the Brady model. Also, we investigate the MOS suggested by ITU-T as a standard measure to evaluate voice quality. We confirm that the proposed scheme achieves high link utilization and that the VoIP service QoS of all users in the networks is satisfied. We expect the results of this study to contribute to improving link capacity for supporting VoIP services.