Thursday, March 11, 2010

international correspondence


TD-SCDMA has the proprietary intellectual property rights international correspondence standard as our country first, has the frequency spectrum efficiency to be high, can realize global roaming, is suitable for the network planning and the optimization, suits each kind symmetrical and the asymmetrical service, the fishing net and the terminal performance-to-price ratio high this 4 greatly prominent superiority. The TD-SCDMA standard usedTime division duplex、Intelligent examination、Union examination、Upward synchronization、Relay cut、Dynamic channel assignment、upshshifting and so on many key technologies, have the unique merit in the wireless network planning and the optimized aspect。The tetherless access network's grade of service and the base depot distribution, equipment's disposition has the close relationship. In the network design, should act according to the different service area the economic development situation, the trade development importance and the network development phase, defines the different network grade of service standard, achieves the good investment effect. The wireless network planning goal manifests specifically in the cover, the capacity, the quality and the cost 4 aspects.The 3G antenna cover request may use the service type, covers the region and the cover probability target attributes. Regarding newly built network, so long as had determined the cover goal, may Large expanse of establish the stand in the entire coverage area, because on the other hand does not have the present net experience and the correlation data uses for reference, lacks the TD local fishing net experience, the network planning can only rely on the theory and the experiment network test result, the wireless network planning accuracy is relatively bad.The designers should act according to the link budget theoretically definite plot radius, what usually use is the COST231-Hata formula takes the urban district environment path loss model.