Signaling Traffic Optimization in UMTS IP Multimedia Subsystem

Abstract

The introduction of the Internet Protocol (IP) Multimedia Subsystem (IMS) in the Universal Mobile Telecommunication System (UMTS) represents an important step towards all-IP networks. IMS undertakes the signaling tasks of the Circuit Switched Core Network (CS-CN), making it needless in the UMTS architecture. As the signaling protocol, IMS uses the Session Initiation Protocol (SIP).This paper investigates signaling capabilities of SIP in IMS in group communications. We introduce a novel mechanism for routing of messages to a group of recipients in IMS. The mechanism is based on sending of a single message to several recipients, instead of sending a message for each recipient separately. This reduces the signaling traffic as well as end-to-end delay of messages. The paper also includes simulation results that show traffic optimization obtained by this mechanism.