中英论文翻译-对照全球移动通信系统本科学位论文.doc
167 浏览量
2023-07-02
20:04:40
上传
评论
收藏 47KB DOC 举报
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.3 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 with common 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. 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 then to 1,800 MHz with personal
communication systems. The history of mobility can split into generations. The first
generation systems were the advanced mobile phone systems (AMPS) in the US, total
access communication system (TACS) in most of Europe and Nordic mobile
telephone system (NMT); which were all analogue systems. The second generation is
vary much dominated by the standard first set out in Europe by the group special
mobile (GSM) committee, which was designed as a global mobile communication
system.
The GSM system is based on a cellular communications principle which was
资源评论
