UMTS标准演进的情况介绍. (2003-07-10 16:36:22). UMTS系统的标准经过多年发展，已 趋于成熟，其标准化工作由3GPP组织完成，到目前主要有四个版本，即R99、R4、R5和R6。 R99网络. 从系统角度来看，R99系统仍然采用分组域和电路域分别承载与处理的方式， -evolution of the UMTS standard briefing. (2003-07-10 16:36:22). UMTS system standards after years of development, has become mature, and its standardization work completed by 3GPP organizations, to the current four major version, R99, R4, R5 and R6. R99 network. From a system perspective, the system is still used R99 packet and circuit domain were carrying and processing,