全球移动通信系统GSM (Global System for Mobile Communication)
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全球移动通信系统GSM (Global System for Mobile Communication)(中文6200字,英文4000字)
全球移动系统的成功标志着通信正朝着更个性化、更方便的系统发展。在商业上使用手机的人很快就会意识到,在个人生活中任何时间、任何地点打电话的能力都会迅速成为一种需要,而不是一种便利。
与固定传输系统不同,个人通信革命发生的速度和速度高度依赖于技术和通信标准。
对于手机而言,实现服务占用的三个关键要素是成本、手机的大小和重量以及连接的成本和质量。如果其中任何一个是错误的,特别是前两个,那么市场增长很可能受到严重限制。
固定电话业务是全球性的,互连方式从同轴电缆到光纤和卫星不等。国家标准是不同的,但通过公共接口和接口以及接口转换,可以实现互连。对于移动设备来说,这个问题要复杂得多,需要漫游,这就需要复杂的网络和系统。因此,在移动领域,标准问题比固定系统对成功更为关键。此外,移动领域的频谱分配也存在着一个棘手的问题。
最初在模拟模式下运行的移动系统(仍在运行),在450兆赫频段,通过数字GSM移动到900兆赫,然后通过个人通信系统移动到1800兆赫。流动的历史可以分为几代。第一代系统是美国的先进移动电话系统(AMPS)、欧洲大部分地区的全接入通信系统(TACS)和北欧移动电话系统(NMTS):它们都是模拟系统。第二代主要是由集团特别移动(GSM)委员会在欧洲制定的标准,该委员会设计为全球移动通信系统。GSM系统基于蜂窝通信原理,这是美国贝尔系统工程师在20世纪40年代首次提出的概念。这一想法源于增加网络容量的需要,并绕开了这样一个事实,即在人口稠密的地区运行的广播移动网络可能会被极少量的同时呼叫所阻塞。蜂窝系统的功能是允许频率重复使用。
外文文献:
GSM (Global System for Mobile Communication)
The success of mobile systems across the world is a sign that communication is moving towards a more personalized, convenient system. People who have to use a mobile phone on business soon begin to realize that the ability to phone any time, any place in one’s personal life rapidly becomes a necessity, not a convenience.
The speed and rapidity with which the personal communications revolution takes place is, unlike fixed transmission systems, highly dependent on technology and communication standards.
For mobile the three key elements to achieving service take-up are the cost, the size and the weight of the phone, and the cost and quality of the link. If any of these are wrong, especially the first two, then market growth is liable to be severely restricted.
The fixed telephone service is global and the interconnection varies from coaxial cable to optical fiber and satellite. The national standards are different, but with common interfaces and interfaces and interface conversion, interconnection can take place. For mobile the problem is far more complex, with the need to roam creating a need for complex, networks and systems. Thus in mobile the question of standards is far more crucial to success than fixed systems. In addition, there is also the vexed question of spectrum allocation in the mobile area. |