A Analysis And Study Of Call Model Based On Mobile Softswitch

In the course of the evolution of communication network towards Next Generation Network, Softswitch technology has been widely used. The concept of thoroughly separation of call control, bearer and service function is gradually introduced into the ftxed network or mobile core network. Before the time that China formally launches the commercial usage of 3G system, many communication equipment producers are quickening their steps to the researching and developing of 3G system sand the core network adopted the Softswitch technology.The thesis discusses the mobile Softswitch technology is introduced with following aspects: the basic theory of mobile Softswitch, the network architecture, the function principle of call server and media gateway, and the protocols mainly used in mobile Softswitch network. which are mainly used in Distributed MSC-Server call model. The thesis mainly comprosed the mobile telecommunication and Softswitch technology, Call model is the core in design mobile Softswitch. In analyzing the foundation of the existing mobile Softswitch call model, putting forward a kind of MSC- Server call model base on distribution .This model aims at to move set that initiate the forward direction bearer establishment,whitch realized the call control flow and route selection, the call-controlling model realizes the separation of call control and medium bearer, and the service logic and call control, the model that allows the accessing of multi-protocols, makes call control independence potocols of the bottom bearer, realized the design request of the call control in mobile Softswitch.In order to improve the utilization factor of circuit, it adopts many routing aritharithmetics in Circuit Distribute Controller for load sharing and three managed methods of circuit in Call server to reduce the possibility of occupying the same circuit. As to MGW selection, based on the resource congestion control package and overload control package of H.248 protocol, the call admission control of MGW was discussed, and simple OPNET simulation of MGW call admission control was described. The result of the simulation indicated that the application of MGW call admission control ensured higher call success ratio and better network capability at the same time.