Application Research Of Signaling Optimization In Session Setup Based On Ip Multimedia Subsystem

Considering the convergence of internet operator and traditional telecommunication operator, 3GPP (3rd Generation Partnership Project) introduces IMS (IP Multimedia Subsystem) as the developing direction of core network. In the session setup produce of IMS, there are still lots of problems in supporting of service trigger, Quality of Service (QoS), session continuity. This thesis studies the strategy of service trigger and the compression of SIP signaling. So these strategies can optimize the produce of signaling and the delay of session setup.This thesis proposes a modified service trigger mechanism N-SCIM (New SCIM) based on SCIM (Service Capability Interaction Manager). Firstly, this thesis introduces the background, research status, the concept of related concept of IMS as the basis of study after. Then, this thesis describes the structural model of N-SCIM and the produce of service trigger in detail. With the S-SCIM in S-CSCF side and the A-SCIM in AS side, N-SCIM realizes the new service trigger process, which avoids too much signals transmission between S-CSCF and AS.This thesis proposes an improved compression algorithm which includes LZSS and arithmetic coding with pretreatment on basis of the existing compression algorithm of SIP. Firstly, the message is coded with pretreatment. Then, the message is compressed by LZSS. Finally, the message is combined with arithmetic coding. The simulation experiments are made based on typical SIP session scene. The results of experiment confirm that the improved algorithm can improve performance, shorten message size and reduce transmission delay.