An energy-efficient delay reduction technique for supporting WLAN-based VoIP in SmartPhone

For non-real time data such as Web or e-mail, the 802.11 PSM scheme can be a useful mechanism for reducing power consumption effectively. However, there are some limitations when these are used for voice communication in which the main traffic is composed of delay-sensitive data like voice or call signaling. In this paper, in order to overcome the limitations, we present an efficient power saving scheme which can minimize power consumption while guaranteeing the delay constraint during call signaling and talk time. Furthermore, in order to illustrate the aims of the proposed approach, the terminal systems are implemented and evaluated by measuring average call connection delay and power consumption. The experimental results show that our approach can minimize traffic delay and power consumption, and find an optimal sleep threshold value according to network condition changes.