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国际互联网是一次伟大的通信革命,现在,另一场更为彻底的变革即将发生,这就是第三代移动通信或3G。第一代手机面世后,网络可以自动将无线电波从一个蜂窝切换到另一个蜂窝,保证用户移动时呼叫不受影响。但是1G系统存在一个关键缺陷,这就是系统的分配频谱使用率低,而且模拟技术很容易被人窃听。第二代系统从1990年开始启动,它基于数字技术、高效、保密,能够提供一系列的功能,包括语音信箱、股票交易和文本消息
The Internet is a great revolution in communications. Now another more radical change is imminent. This is the third generation of mobile communications or 3G. The first generation of handsets available, the network can automatically switch radio waves from one cell to another cellular to ensure that users move calls are not affected. But there is a key flaw in 1G systems, which is the low spectrum utilization of the system’s allocated spectrum and the ease with which analog technology can be eavesdropped. Launched in 1990, the second-generation system is based on digital technologies that are efficient, secure and offer a range of features, including voice mail, stock trading and text messaging