The World Radio Conference in 1992 (WRC-92) allocated 1900 ~ 1920 MHz and 2010 ~ 2025 MHz as the 3G TDD core frequency band. In China, the 2300 ~ 2400 MHz band is added as a supplementary TDD band. As the only 3G TDD technology supported by many manufacturers, TD-SCDMA is the most suitable system for this frequency band. The same frequency bands allocated for TD-SCDMA globally laid the foundation for the wide deployment of this system throughout the world, while being conductive to global roaming.
Figure 3G Frequency Allocation
By the end of July 2006, a total number of 157 3G licenses had been awarded. Among them, 139 licenses adopted UMTS technology, four licenses adopted cdma2000, and 117 licenses can adopt TDD mode. Over 100 TDD licenses are allocated in the Asia-Pacific and European areas, in 1900 ~ 1920 MHz and 2010 ~ 2025 MHz frequency band. Currently, most of these TDD frequency bands are idle. How to effectively use the existing valuable 3G TDD spectrum resources becomes a focus of operators in various countries.
As the only 3G system that uses TDD technology, TD-SCDMA can dynamically adjust resources of the uplink/downlink bearing, and is very suitable for providing mobile data services. TD-SCDMA provides the highest spectrum utilization amongst 3G technologies. The implementation and improvement of TD-SCDMA-specific key technologies, such as smart antenna and joint detection, enables TD-SCDMA to greatly utilize the spectrum. With the HSPA technology, TD-SCDMA is ideal for providing high-speed radio data services capable of independent networking. For those UMTS operators with a shortage of frequencies, TD-SCDMA is a good choice to build a supplementary data service network.
TD-SCDMA also effectively suppresses interference between users and uses constant spectrum spread factors, having a minimal breathing effect. In addition, Node B coverage is mostly unrelated to the service load, while coverage area of different rates of services varies slightly. These features greatly reduce the difficulty of TD-SCDMA network planning as well as the operation and maintenance of mobile networks. For most GSM operators, it is also an excellent independent 3G evolution technology. Currently, TD-SCDMA and GSM networks can be integrated by formulating appropriate interoperability strategies to help the operators with smooth evolution from 2G to 3G networks. This protects earlier investment, retains valuable customer resources, and ensures good customer experience. TD-SCDMA chip manufacturers have developed dual-mode chips that support TD-SCDMA/GSM and terminal manufacturers have developed numerous TD-SCDMA/GSM dual-mode terminals, making it ready for a rise in this market.
As TD-SCDMA generates successes in the Chinese market, there are many system equipment and terminal suppliers that provide complete solutions for various scenarios, forming a complete, dynamic industry chain. The numerous and highly competitive TD-SCDMA equipment suppliers and solution suppliers inject new vigor into the global mobile communication market. This is also a powerful guarantee that ensures the space of TD-SCDMA systems in the global communication market.