中英论文翻译对照：全球移动通信系统.doc

GSM(Global System for munication)
The ess of mobile systems across the world is a sign munication 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 es a necessity, not a convenience.
The speed and rapidity with which the munications revolution takes place is, unlike fixed transmission systems, highly dependent on technology munication 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 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 fibre and satellite.
The national standards are different, but mon interfaces and interface conversion, interconnection can take place. For mobile the problem is far plex, with the need to roam creating a need works and systems. Thus in mobile the question of standards is far more crucial to ess than fixed systems. 4 In addition, there is also the vexed question of spectrum allocation in the mobile area.
 Mobile systems originally operated in analog mode in the 450 MHz band, moving later to 900 MHz with digital GSM and th