Performance evaluation of SIP voice conferencing over IEEE 802.11

Voice conferencing with handheld devices over IEEE 802.11 wireless networks enables real-time collaboration between geographically distributed users. A number of conferencing models have been proposed with pronounced limitations when applied to IEEE 802.11 with handheld devices. In addressing this, we propose a session initiation protocol (SIP) based conferencing architecture that takes into account these specific limitations. The proposed model is shown to improve user scalability and conservation of battery energy. This article reports how we set up simulation scenarios, how we compared and analyzed the QoS performance of Static User with Mobile User using our proposed conferencing model. The results indicate that there is a longer delay and more packets are dropped when the UA is in a mobile environment and we identify factors that influence this delay.