Research On The Model Of Mobile Soft Switching System Using Satellite Link

The 3G networks target on providing a mobile roaming system with global coverage eventually. World wide, mobile operators try their best to roll out networks to expand network coverage and hold their market share. Compared with the mature networks in the urban area, there are still quite much remote area uncovered. The main reason is that it could be quite expensive or even impossible to deploy transmission network there. Satellite communication systems could then serve these area for mobile coverage purpose perfectly.However on another hand the exclusive cost for a satellite system serving for mobile communication limit its broad commercial deployment in turn. This thesis is then to propose a method to achieve global coverage of mobile soft switching systems by use of satellite technology with lower cost. Different with traditional satellite technique research, we will focus on research for the model of mobile soft switching system using satellite link. The logically split of call control function and transmission function inside a mobile soft switching system implies the corresponding function entity can reside in different physical locations. Mc and Nb interface can then be carried over satellite link, as proposed in this paper, so as to extend the coverage of switching networks by dint of globality of satellite systems. As a result in this system, end users from access side will then easily enjoy the global roaming not necessary to upgrade their cell phones. While network operators can build up a system with simple node model, which then efficiently means cost cut-down.Particularly in the paper, we start from the overall network architecture of a mobile network system, introduce the main nodes inside it and also the interface between those nodes. We investigate the functionality of these nodes, as well as the realization of corresponding protocol transmission over them. We propose several modules for the mobile network system and introduce our implementation, i.e. carrying Mc and Nb interface by using satellite link. However introduce of the satellite technology would bring in extra transmission delay for those protocol transmission or even cause call set up failure. In order to minimize this negative impact, we then make proposal for parameter value adaptation.Finally we introduce network layout and architecture in the lab test, and also carry out the functionality test and high traffic test for this system. at same time billing and voice quality is evaluated as well. According to the testing result, this model of mobile soft switching system using satellite link is fully functional.This system was deployed successfully in an island country resides in South-East Asia after the research work is concluded. And now it is operated well. Meanwhile more and more deployments of the system are carried out in Africa and South America.