第二代移动通信系统

GPRS（通用分组无线业务）是第二代移动通信系统向第三代移动通信系统平滑过渡的主要方案。

GPRS ( General Packet Radio Service ) is the most important transition from the second generation communication system to the third generation communication system .

研究第二代移动通信系统向第三代移动通信系统的演进，深入研究WCDMA的网络体系结构及其接口规范。

Research the evolution of the mobile telecommunication system from 2G to 3G , the network architecture and interface specifications of WCDMA .

第二代移动通信系统（2G）是数字移动系统，能提供低速率数据业务。

Second generation mobile communication system ( 2G ) is digital cellular system which can provide low-speed data business .

在第二代移动通信系统向第三代移动通信系统的演进中，必然会出现2G系统和3G系统共存的环境。

In the process of the second generation mobile system to the third generation mobile system , the coexistence of 2G and 3G will be appeared .

目前广泛应用的移动通信系统为第二代移动通信系统（2G），随着用户对数据业务需求的增加以及多媒体业务的应用，第三代移动通信系统（3G）成为人们关注的热点。

Currently widely-used mobile communication system is second-generation mobile communication system . With the increasing of data service demand and multimedia service 's application , the 3 ~ ( rd ) generation system appears and becomes a hot research topic .

日本邮政省依据国内通信市场的发展速度和第二代移动通信系统的不足，制定了2001年引入第三代移动通信系统的时间表，同时向ITU提交了标准提案。

In the light of the domestic telecom market development status quo and the drawbacks of the second generation mobile system , the MFT of Japan has mapped out a timetable for the introduction of the third generation mobile communications system , and submitted a proposal to the ITU .

近十年来，移动通信的发展十分迅猛，第二代移动通信系统正逐步被第三代移动通信系统所取代。

Mobile communications systems have been developed very fast in the past decades . The second generation mobile communications systems are gradually replaced by the third generation mobile communications systems .

直放站作为移动网络覆盖的重要补充已经在第二代移动通信系统中得到了广泛的应用，它在有效增强网络覆盖面积和覆盖强度的同时降低了运营商的网络建设成本。

As a important complementary equipment , Repeaters have been widely used in 2G mobile communication system . Repeater can enlarge the area of mobile network usefully and reduce the cost of building network .

第一章介绍了移动通信发展状况和发展趋势，阐述了第一代移动通信系统、第二代移动通信系统、第三代移动通信系统、第四代移动通信系统的特点，以及未来移动通信发展状况。

Chapter I introduced the developments and trends of mobile communication , introduced the characteristics of the first generation of mobile communications systems , the second generation of mobile communications systems , 3G mobile communications systems and fourth-generation mobile communication system and the future of mobile communications developments .

第二、三代移动通信系统安全体系的分析与比较

Analysis and Comparison on the Security Architectures of 2G & 3G Mobile Communications System

自20世纪90年代，蜂窝移动通信从第一代模拟蜂窝移动通信系统发展成第二代的数字移动通信系统。

1990s , Cell mobile communication system develop the second generation of digital mobile communication system into while being the first generation of mobile communication .

与第二代移动通信相比，WCDMA系统应用了许多关键技术，如RAKE接收、多用户检测、智能天线、无线资源管理技术、功率控制技术。

Comparing with 2G mobile communications , the WCDMA system applies lots of key technology , such as RAKE take-over , multi-user examine and measure , aptitude antenna , wireless resource manage technology and power control technology .

自20世纪80年代中期以来，蜂窝移动通信已从第一代的模拟蜂窝移动通信系统发展到了第二代的数字蜂窝移动通信系统，并正在向第三代蜂窝移动通信系统演进。

Since the mid of 1980 's , cellular mobile communications have developed from the first generation analog cellular mobile communications systems to the second generation digital cellular mobile communications systems . Now they have been evolved into the third generation cellular mobile communications systems .

第三代移动通信系统以其技术上的优势，势必将取代第二代移动通信系统。

The third generation of mobile communication system will definitely replace the second-generation mobile communication system with its technological advantage .