The influence of radio transmission at 2GHz into buildings was quite obvious

the result were analyzed by for network structure of macro-cell in UMTS system.The relation of restriction between the three factors

including building penetration loss

coverage credibility and the link margin also were discussed based on the principle of equilibrium cov-erage in the indoor and the outdoor.How to take the expectation of building penetration loss and its’ value were recom-mended were also presented in detail to obtain the much more optimum network structure of macro-cell.With the ap-proach of equilibrium coverage

the waste of base station and the difficulty of controlling will be avoided to the utmost.On the other hand

the insufficiency of base station will also be prevented

and the network performance will be ade-quately exerted.