传输网作为运营商规模最大、结构最为复杂的基础网络,演进的平滑性、兼容性是最为关键的问题。通过对3G传输网分类及结合3G各业务阶段的发展特点,分别探讨了接入和核心传输网传输技术、方案的演进过程。总之,在网络建设的不同时期,演进应根据网络情况和需求采用不同的3G传输方案,对于PTN的引进则从传输网的核心层逐步向接入层推进。 Transmission network as the largest operator, the most complex structure of the basic network, the evolution of smoothness, compatibility is the most crucial issue. Through the classification of 3G transport network and combining the development characteristics of various business phases of 3G, the evolution of access and core transport network transmission technologies and solutions are discussed respectively. In short, in different periods of network construction, the evolution should adopt different 3G transmission schemes according to the network conditions and needs, and the introduction of PTN will be gradually promoted from the core layer of the transmission network to the access layer.