The voice-over-Internet protocol (VoIP) has attracted a great deal of attention in the field of wireless mobile networks. In this paper, we propose an improved ertPS scheduling algorithm for VoIP services in IEEE Std 802.16e system. It can solve both the problems waste of uplink resources caused by the UGS algorithm as well as MAC overhead and access delay caused by the rtPS algorithm, it also identify whether the channel state is good or bad. Conclusions are drawn for an IEEE 802.16e wireless system working in point-to-multipoint (PMP) mode, with time division duplex (TDD). The target air interface is WirelessMAN-OFDM.