One-node-based mobile architecture for a better QoS control

Although IMS (IP multimedia subsystem) brings a large set of new services and offers service convergence, it introduces complexity on network procedures and architecture. This paper focuses on IMS session establishment procedure and highlights the long delay introduced by this procedure. It also raises failure problems encountered when only partial radio resources are available for the requested service. To solve these issues, we propose a new architecture, called UFA (ultra flat architecture) which is an IMS distributed and flat architecture composed of only base stations. We define session establishment procedure for UFA and describe the way it handles access network resource information to adapt the service accordingly. We compare UFA and IMS classical architectures in terms of session establishment delay. Evaluation uses queuing theory and shows that UFA enables a considerable gain.