Congestion Control Policies for IP-Based CDMA Radio Access Networks

In this paper we propose and evaluate three congestion control mechanisms, admission control, diversity control, and router control, to maximize network capacity while maintaining good voice quality. We first propose two new enhancements to CDMA call admission control so that a unified view of both IP RAN and air interface resources are taken into consideration. We then introduce a novel technique called diversity control to exploit the soft-handoff feature of CDMA networks and drop selected legs to degrade quality gracefully during congestion. Finally, we also study the impact of router control using active queue management techniques to reduce delay and minimize bursty and correlated losses.