Research On Optimized ICS Solution

IMS breaks the bottleneck of legacy Circuit Switch network due to its openness and flexibility. Nowadays, the trend of IMS being the next generation core network is widely accepted. But the evolution of a network is never an easy task, it takes a long time. At this point, IMS and CS will coexist for a long period. So it is most important to deal with the relationship between IMS and CS network and to maximize the efficiency of the two networks. The idea of ICS (IMS Centralized Service) provides with a wonderful solution to the issues that brought up by the coexistence of IMS and CS.ICS means that IMS network controls the services for users via various kinds of accesses. The CS core falls back to an access means of IMS network.3GPP has brought up with two ICS solutions say UE based and Network based. These two solutions both have full network abilities of ICS, but they also meat montains when being deployed. So it's really important to make optimization to existing solutions to make them feasible. This paper chooses the Network based as the basic solution because it has more advantages than the UE based, and then brought up with two optimization ideas:one is to use the existing network elements to fullfil ICS tasks, it can cut off expense observably but will lose key network ability; the other one is to setup a EMSS for each some area, so much less EMSSes will be needed and this will cut off expense of network upgrade but have full network abilities. The idea of setup centric EMSSes has better network ability than the other one, so this paper takes the centric EMSS idea. Taking the statistices of real network into account, the centric EMSS solution is much more feasible than the original one.