4.1　CS Domain Network Architecture

4.1.1　The CS core network of WCDMA system should be divided into three architectural layers consisting of mobile service local network，intra-provincial network and national network.

1　Mobile service local network has basically the same geographical scope as that of PSTN.

2　The intra-provincial network constitutes multiple mobile service local networks within the provincial territory，and the inter-provincial network is composed of manifold intra-provincial networks.

3　According to networking needs，the entire country may be divided into several operation tandem areas.Within each operation tandem area one provincial capital may be selected to serve as the central city of large regions.

4.1.2　International communications network and domestic communications network are independent of each other.The inter-communications are implemented through the international inward and outward exchange system.