| From R4 standard the core network of WCDMA begins to use soft switch technology to fundamentally rebuild the CS (Circuit Switched) domain based on R99 standard. Control plane and bearer plane are separated in R4 network, so the MSC server is divided into MSC and MGW in R4 standard, among which MSC is located in the controlling layer of core network and is the call control entity of core network, providing control function of establishment, maintenance and realization for basic call flow.This thesis researches the call control software system in the MSC of WCDMA network.The conception of mobile soft switch and three main parts: WCDMA core network system architecture, call control module function analysis, call control module analysis and realization are intensively researched in this paper. Firstly, the conception of soft switch is introduced, the architecture of WCDMA core network system and it's functional entity are intensively studied; Secondly, based on the function analyzing of the connection management layer in R4 standard, the call control module is presented and main functions of call control module are also discussed here. Finally, the paper discusses the implementation of call control module in detail.This paper describes the analysis, design and implementation of the number analysis function. It uses the method of Additional Calling Number Transfer to solve the problem that calling number cannot be obtained with ISUP signal in some country. In the implementation of call restriction, the paper introduces the concept of Virtual Attribute, that combines different means of call restriction. And the thesis analyses the implementation of bearer operation in call control module. It uses a middle bearer control layer which shields the bearer control in the call control module from the influences incited by the complexity of physical network structure. By this means, the complexity operation problems between the services and physical bearer in the call control is resolved. |
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