Policy and Charging Control for Virtual IMS Client

Abstract

In its latest releases, the IP multimedia subsystem (IMS) service model provisions Quality of Service (QoS) and enforces charging through its policy and charging control (PCC) architecture. By exploiting the intrinsic segregation of the signalling and media planes that the IMS service model offers, a virtual IMS client could be developed that simplifies terminal device implementation by offloading signalling and session management tasks to a remote server. In this paper, we study how the IMS/PCC architecture can be deployed in conjunction with a virtual IMS client. Although a virtual IMS client assigns the signalling tasks (accomplished through session initiation protocol and session description protocol) to a remote server, information related to QoS should be propagated back to the access network and also the end user's terminal device. Therefore, designing a virtual IMS client that only deals with the media plane is challenging. In this paper, we propose a PCC architecture for the virtual IMS client that keeps the end user's terminal as simple as possible while providing the necessary functions of the IMS/PCC architecture. Since QoS provisioning is access network specific, we explore the proposed architecture for two predominant networks access methods: UMTS from 3GPP and WLAN from IP-based access.