An efficient uplink admission control for ertPS in IEEE 802.16

In this paper, we propose an efficient call admission control scheme for ertPS, one of QoS services in IEEE 802.16, which is designed for Voice over IP. In ertPS, a user´s unused spare bandwidth is temporally shared with others, which can achieve the efficient bandwidth usage. Since the bandwidth sharing happens among the connected calls, a BS should retain the appropriate number of connected calls. If it has too small number of calls, the unallocated spare BW will be waisted. Otherwise, the excessive number of calls accepted by the BS may cause cell-overloading and call-dropping. By using the statistical multiplexing and probabilistic guard channel reservation, the proposed scheme increases the bandwidth utilization. The results show that the analytical model and the simulation are the very close, and our scheme can achieve 10% less blocking probability of a new call and higher utilization of bandwidth than a conventional guard channel scheme.