Context-Aware Signaling for Call Differentiation in IMS-Based 3G Networks

Service differentiation is an active topic in 3G networks, which aim at supporting a diversity of IP multimedia services (with different QoS requirements) and users (establishing sessions with different levels of importance). In this paper, we propose a network level call differentiation scheme in IMS-based 3G networks. This scheme defines three new classes of calls offering different priorities/guarantees to the user. Service differentiation is achieved at the session signaling level by relying on a context-aware resource allocation strategy. An extension to the 3GPP IMS architecture is proposed to realize the service differentiation scheme and a proof-of-concept prototype is built using SIP and COPS as implementation technologies. Unlike other signaling level schemes, the system proposed here offers flexible QoS negotiation mechanisms to the user, provides preferential treatment at the beginning and during sessions, and takes into consideration the characteristics of the multimedia, multiparty, service environment offered by 3G networks.