Congestion and Access Control Policies of Multi-Priority Instant Services for IP-Based CDMA Radio Access Networks

IP radio access networks (RAN) are expected to employ CDMA as the next generation access networks (Bu et al., 2004). In the previous work, the problem about congestion of voice in IP-based CDMA RAN was examined and several policies were brought forward and evaluated with the assistance of simulations (Kasera et al., 2005). In this paper, we first develop a mathematical model to investigate the multi-region soft-handoff of the IP-based CDMA RAN and analyze its systematic characteristics. The effectiveness of the developed mathematical model is demonstrated by simulations. We then propose a max-leg-limit control policy to improve the system performance in terms of the blocking rate and the number of users. We also extend it to a more general situation, where instant video, instant data and voice are provided within an IP-based CDMA RAN. For such a multiple priority instant service system, we propose two control mechanisms, borrow-leg and router buffer preservation, to control the quality of services. Simulation shows that the control mechanisms are effective in keeping the quality of multi-priority services.