| IP multimedia subsystem (IMS) was defined in release 5 for the first time by 3GPP, the marked characteristics of which is the SIP-based session controlling and access-irrelevant. In the future, the multimedia services need high quality on real-time and delay. QoS(Quality of Service) guarantee for multimedia services is a serious issue in IMS. This paper introduced the overall architecture of IMS. The policy-based QoS management in IMS and the end-to-end QoS signaling flow in session setup procedure were analyzed. Then policy-based management mechanism of the in-depth analysis and research was taken, and extended the SIP protocol. OPNET-based simulation implementation model was constructed, focusing on the strategy of the Policy scheduling algorithms simulation . The traditional QoS mechanism based on policy is analyzed, and a new QoS mechanism based on policy is proposed. The new mechanism improves the function of PDF (Policy Decision Function). Finally, simulation results verified the feasibility of the scheme for the future provide. |
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