2G/TD Core Network Intergration

The first 3G technology TD-SCDMA network in the world, "China Mobile's extended TD-SCDMA experiment network for trial-scale application" is built in eight cities of seven provinces in the china by China Mobile in 2007. During TD initial network construction stage, users can handover to 2G networks business, in the TD poor or no coverage areas. As an independent between the TD and 2G network, there are some problems:the delay of location update is longer due to the network interoperability between two kinds of systems, which results in a lower success rate of the network switch; GSM/GPRS network interoperability required the Gateway, BG and more circuitous routing; Different phone number in the TD and 2G network is not benefit to the development of TD system; Core network construction, equipment utilization rate and maintenance have a high investment risks.Based on the above issues, this thesis proposed a core network convergence scheme between 2G and TD, which make the access network of same or adjacent area of coverage access the same MSC and SGSN. This method reduces the cell weight 2G/TD systems selection, location update and switching operations and improves user experience; After adjusting the network structure, the local call via MSC instead of the GMSC, etc. The switching, resources and routing were reduced; Building integrated HLR,2G, and TD network removed the user division, which is help to the rapid development of TD system; sharing the same core network can improve equipment utilization, protect the original investment and reduce investment risk and the maintenance.In 2009, we presented a meet about the city 2G/TD core network integration. Our task is focus on the analysis of the current urban network 2G and TD. By selecting a wireless coverage area, we made a final hardware and software upgrade scheme. During the implementation process, there were three stages of the network test:sharing of MSC, not sharing of MSC and handover, re-selecting delay and network performance test. The results show that key performance of TD, GSM network are normal and stable. The proposed scheme increased six percent of the success rate of handover and greatly improved user experience.The proposed scheme can provide a network convergence method and the feasibility of it was proved by engineering realization.