Energy-saving VoIP over wireless LANs

Energy consumption is a major issue in the wide deployment of Voice-over-IP (VoIP) over IEEE 802.11 wireless LAN. This energy can be conserves by staying in sleep mode during VoIP call over WLAN. To this end, researchers have conducted extensive simulation and analytical studies to determine the consumed energy during VoIP call in different WLANs. These previous works, however, assume stations are always awake during a call. In 2005, the Wi-Fi Alliance proposed a power saving mode extension that allows stations to retrieve packets from the Access Point (AP) at any time. In light of this development, we propose a sleep-awake mechanism in network layer is pulse protocol with Green call Algorithm. where stations sleep for different time intervals. Which reduce considerable energy consumption?