Hybrid Energy-Saving Algorithm Considering Silent Periods of VoIP Traffic for Mobile WiMAX

Recent broadband wireless access systems apply voice over Internet protocol (VoIP) for their voice services, so a mobile station (MS) requires an efficient energy-saving algorithm for VoIP services to prolong its battery lifetime. The IEEE 802.16e system called Mobile WiMAX provides the power saving class (PSC) of type II as an energy-saving algorithm for VoIP service, but it is not originally designed to consider silent periods of VoIP traffic. Therefore, we propose a new hybrid energy-saving algorithm suitable for VoIP services with silence suppression, which basically follows PSC II during talk-spurt periods, but uses the truncated binary exponential algorithm of PSC I during silent periods. The analysis and simulation results show that the proposed hybrid scheme reduces power consumption effectively during silent periods while satisfying the maximum allowable end-to-end delay and low packet drop probability constraints with respect to the quality of service (QoS) of VoIP.