The Design And Realization Of. Mobile Communication Core Network Based On Lamination Architecture

With the development of computer and communication technology, the demand for communication services is also growing for people. In order to provide users with more flexible and variety of services and to meet the personalized needs of users, it is admitted that building a universal service network which can load and traffic voice,data and multimedia services at the same time.Under the tendency of service-driving and network convergence, NGN network-model arises, which can load voice, data, and multimedia services efficiently through hierarchical and open structure in the packet switching network.The next-generation network will achieve independent relatively Lamination architecture by separating services and call control,and separating call control and bearing control. Open protocol and API interface are adopted between layers, to support the integration of a variety of heterogeneous network. As the core technology of next generation network-control-layer, Softswitch can archive the separation of call-control and media transmission through media control protocol MGCP/H.248. Softswitch which is based on Lamination architecture can be seen as the concrete implementation mode of NGN architecture. Softswitch has been applied to fixed communication and mobile communication widely including Softswitch long-distance aggregation network,Softswitch fixed local network, 3GPPR4 mobile Softswitch and so on.This paper is complished based on mobile core network construction projects of some mobile communication operators. It takes into account the 2G to 3G mobile communications network evolution,resolves the problems of high loads and high utility ratio of system resource by introducing mobile softswitch equipment based on layered architecture based on Lamination architecture to build a new client Bureau. At first, the background of Softswitch, the features of technical and the widely application both at home and abroad are introduced in this paper. The Lamination architecture of softswitch and main device are analyzed in chapter 2, especially the frame structure of Softswitch ,the application of MSC Server and MGW. Then the function block diagram of mobile Softswitch system was given through the research on load-mode of every logical interface and application protocol. The function of Softswitch system was described in detail. It is mobile Softswitch that the function controls and loading of MSC / VLR based on circuit-switched in the traditional mobile network are separated. The control function is completed by the new equipment MSC Server. MSC Server is at control layer in the core network of mobile Softswitch system, core equipment at control layer, mainly to do various call control, responsible for the corresponding transmission of business process information. Loading function is completed by the new equipment MGW. In the core network of mobile Softswitch system, MGW is at a transmit layer, a core equipment of transmit layer. The main work of transmit layer is to do convert various multimedia resource. Mobile Softswitch architecture achieved centralized control, distributed exchange. The separation of control layer and loading layer make the way of networking more flexible; reduce the number of main station, save transmission resources.The relative problem of mobile Softswitch networking was discussed in chapter 3, and also, the intercommunication of SS7 Signaling Network, PSTN/PLMN, Intelligent Network, H.323 Network and Fixed Softswitch Network was analyzed. Next, the reliability of mobile Softswitch, demand of Signaling Network on IP loaded, and the networking protocol of IP Signaling Networking are researched. At last, the evolution of mobile communication network and the function of mobile soft switch in the evolution were given. We can know that when mobile soft switch network communicate with traditional network, the signaling passed signaling gateway and convert into narrow band SS7 ,and media stream passed media gateway convert into E1 circuit or STM-1 based on TDM. The signaling of R4 Network mainly include BICC which used in calling control between the MSC Server , MAP,CAP,BSSAP signaling for mobile user management and intelligent business touched between MSC Server and HLR, and H.248 protocol between MSC Server and MGW. The H.248 signaling used in the media control, transmitted and processed by MSC Server and MGW. Considered the important position which MSC Server located in the network, to achieve the mobile network's security and reliability, it proposed 5 kinds way to avoid the disaster and backup.The forth chapter introduced the present situation of a certain mobile operator's switching network.and analysis the situation of the switches undertaken through the use of the historical data of exchange system resources table. According to problem of the network load is higher in some switching center , taking into account the evolution of the network, we introduced the Softswitching equipment network to solute it.Chapter 5 of this paper is the core part. According to results of analyzing core network of certain operators, we propose general principles that introducing softswitch equipment based on structure R4, inline with the spirit of"starting from the market, for the target of services and effectiveness". Network structure should be simple, flexible, and easy to transit smoothly to 3G.. According to the general principles of the network construction combined with the network present situation of the operator, through the utilization of network resources for data analysis, we mainly resolve problems of system capacity efficiency in business areas and high utility ratio of resource. First of all, we forecast the demand of business and system function, determine the whole business demand based on A port traffic. Through historical data and the establishment of the traffic model, we can predict the demand for the business district BHCA, forecast the business district MSC capacity requirements, VLR capacity requirements. According to the forecasted capacity demand, in the central cities we can set up MSC Server and hierarchical structure networking mode that separate control layer and load layer of MGW in the city which is required capacity expansion. And selected MSC POOL disaster recovery mode, we designed a mixed network structure with the mobile softswitching equipment and traditional Switch. According to the guiding ideology of soft switching, Mc interface (between MSC SERVER and MGW) using IP approach capacity, MGW also offering Signaling Gateway (SG).In accordance with the protocol loading by Softswitching Mc interface, we computed the information flow of every protocol, thereby calculated Mc interface bandwidth requirements. The structure of the signaling network is then designed.In the end of this paper, concluded the networking process, which resolve the problems existing in present network by introducing Softswitching equipment based on Lamination architecture in 2G core network of mobile communications. We summarized the experiences of the mobile communication network's further evolution, and prospect the problems of network security and QoS when using full IP loading, and the problems how to fully use present 2G core network MSC Server and MGW resource when building 3G core network in the future.