Differential VoIP service in Wi-Fi networks and priority QoS maps

Differential VoIP services for Wi-Fi will greatly enhance the experience of mobile wireless users who have requested premium service for their VoIP applications. In this work we present detailed simulations of modified 802.11b protocols that purport to provide differential service to wireless VoIP users. The modified protocol we identify as providing the best differential service whilst maintaining the least starvation to best effort users - involves a modified minimum contention window, combined with a modified back-off time. A detailed differential VoIP capacity analysis of this modified protocol is presented. Also, we introduce the notion of a "priority service QoS map" for wireless VoIP. Such a map is a two dimensional representation of the VoIP QoS metrics available to a mobile priority VoIP user, as a function of location. We outline how our VoIP capacity analysis is used to construct a priority service QoS map, and discuss the practical benefits of relaying such maps to mobile users of wireless VoIP