A Simple Signaling Mechanism for Seamless Inter-Operator Mobility in All-IP Networks

Recent advances in wireless all-IP telecommunications made it possible for the operators to offer more sophisticated services with mixtures of high quality audio, video, data, and interactive applications. However, mobility still poses a challenge for quality of service (QoS) maintenance in such networks as it typically causes large signaling delays which not only result in poor service quality but also in service interruptions. In this paper, we propose a standard-friendly proactive signaling mechanism that minimizes handover delay between access gateways for intra-and inter-operator mobility scenarios. Based on the current standard framework, which was proposed to allow services in the Internet multimedia subystem (IMS) to authorize and control QoS in the Internet and radio tiers, we provide detailed signaling flows and evaluate our mechanism using delay budgets and signaling loads. We show that our method offers measurable delay savings relative to the current systems. We also analyze the signaling overhead of our mechanism using a Markov chain model. Our results related to the signaling delay and load give us confidence that our method can lead to higher perceived quality, more intelligent network selections, and seamless network convergence.