Admission Control Scheme for Voice Calls Guaranteeing Both Packet-Level QoS and Call-Level QoS in IEEE 802.16e

In this paper, we propose an new admission control scheme jointly taking into account call-level QoS based on the dropping probability of handoff call and packet-level QoS based on the outage probability over threshold in IEEE 802.16e where user mobility is allowed and adaptive modulation and coding (AMC) is employed. The proposed admission control scheme is characterized by both a threshold for handoff calls at call-level and the outage probability over threshold at packet-level. First, we investigate the outage probability over threshold at packet-level. In order to determine the threshold, we derive the dropping probability of handoff call by using Markov chain model at call-level. Numerical results show that our proposed admission control scheme protects well the quality of service (QoS) of ongoing calls including handoff calls.