|
1
|
- GSM(Global System for Mobile Communication)
|
|
2
|
- Revision
- Pre-reading Activities
- While-reading Activities
- New words and phrases
- Text organization
- Text and translation
- Post-reading Activities
- Further Development of the Theme-related Specialized Knowledge
- Assignments
|
|
3
|
- Teacher uses the following exercise to help the students to revise the
important expressions or phrases or sentences which were learnt in the
study of last unit.
- Teacher : When I say a phrase or an expression in Chinese, you respond
by giving an English equivalent your learnt in the study of Unit 9
Cellular Mobile Telephone System
|
|
4
|
- Ask the Ss the following two questions related to the theme of the text:
- what have we learned in the Unit 9?
- Possible answers: cellular Mobile Telephone System
- What is cellular Mobile
Telephone System?
- Possible answers: to reuse the allocated frequency band in different
geographic locations.
- How many parts does a basic cellular consist of? What are they?
- Possible answers: 3 parts, they are mobile units, cell site and MTSO (mobile telephone switching
office)
|
|
5
|
- personalize ['pə:sənəlaiz]v. 使个人化
- convenient [kən'vi:njənt]a. 便利的,方便的
- rapidity [rə'piditi]n. 快,迅速
- severe [si'viə]a. 严格的,严重的
- restrict [ris'trikt]v. 限制,约束
- vary ['vɛəri]v. 改变,变化,不同
- coaxial ['kou'æksiəl]a. 同轴的,共轴的
- interface ['intəfeis]n. 分界面,接口
- conversion [kən'və: ʃən]n. 变化,转化
- complex ['kɔmpleks]a. 合成的,复杂的,综合的
- spectrum ['spektrəm]n. 谱,频谱
- vex [veks]v. 使烦恼,使恼火
|
|
6
|
- allocation [ælə'keiʃən]n. 分配,配给
- generation [ʤenə'reiʃən]n. 代,一代
- dominate ['dɔmineit]v. 支配,统治
- cellular ['seljulə]a. 多孔的,蜂窝状的
- simultaneous [simə‘teinjəs]a. 同时发生的,一齐的
- come into play 起作用
- interference ['intə'fiərəns]n. 干涉,打扰
- maximum ['mæksiməm]n. 最大量,极限
- hexagon ['heksəgən]n. 六角形,六边形
- transceiver [træns'si:və]n. 无线电收发信机
- register ['reʤistə]n. 记录器,寄存器
- charge [ʧα: ʤ]v. 要价,收费
|
|
7
|
- uplink [ʌpliɧk]n. 上行链路
- downlink [daunliɧk]n. 下行链路
- access ['ækses]n. 接近,进入
- burst [bə:st]n. 突发,一阵迸发
- overhead ['ouvəhed]n. 管理费,开销
- handover [hændouvə]n. 移交,越区切换
- algorithm ['ælgəriðəm]n. 算法
- entire [in'taiə]a. 整个的,全部的
- roam [roum]v. 漫步,漫游
- in addition to 除……之外
- facsimile [fæk'simili]n. 传真
- in concert 一致,一齐
- perspective [pə'spektiv]n. 远景,前途
- compatible [kəm'pætəbl]a. 适合的,兼容的
|
|
8
|
- Ss read the text and point out the main idea of the text.
- The main idea: the text mainly discussion the principle , function and
operation of the second generation mobile communication system----GSM.
- Ss make an analysis of the organization of the text.
- The text may be divided into three major sections.
- Section1(line 1-20): The rapid development of the personal communication
is high dependent on technology and communication standards.
- Section2(line21-81): GSM provides common standard and uses the advanced
digital technology.
- Section3(line82-87): the third generation mobile communication system
currently is developed in Europe.
|
|
9
|
- GSM(Global System for Mobile Communication)
|
|
10
|
- 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.
|
|
11
|
- 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.
|
|
12
|
- 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.
|
|
13
|
- 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.
|
|
14
|
- The GSM system is based on a cellular communications principle which
was first proposed as a concept in the 1940s by Bell System engineers in
the US. The idea came out of the need to increase network capacity and got
round the fact that broadcast mobile networks, operating in densely
populated areas, could be jammed by a very small number of simultaneous
calls. 5 The power of the cellular system was that it allowed
frequency reuse.
|
|
15
|
- The cellular concept is defined by two features, frequency reuse and
cell splitting. Frequency reuse comes into play by using radio channels
on the same frequency in coverage areas that are far enough apart not to
cause co-channel interference. This allows handling of simultaneous
calls that exceed the theoretical spectral capacity. Cell splitting is
necessary when the traffic demand on a cell has reached the maximum and
the cell is then divided into a micro-cellular system. The shape of cell
in a cellular system is always depicted as a hexagon and the cluster
size can be seven, nine or twelve.
- The GSM system requires a number of functions to be created for a fully
operational mobile system.
|
|
16
|
- The cell coverage area is controlled by a base station which
is itself made up of two elements. The first element is the transmission
system which communicates out to the mobile and also receives
information from it to set up and maintain calls when actually in
operation. The base station transceiver (BST) is controlled by the base
station controller (BSC), which communicates with the mobile switching
center (MSC) ---- the essential link to the local public switched
telephone network (PSTN), and to the subscriber data which is stored in
registers within the system. The subscriber registers allow the GSM
system to check a subscriber who requests the use of the network, allow
access and then set up the charging function, etc. 6
|
|
17
|
- The GSM system was allocated part of the 900 MHz band at the 1978 World
Administration Conference (WAC), the actual bands being 890 to 915 MHz
for the uplink transmission and 935 to 960 MHz for the downlink. The
access method is time division multiple access (TDMA).
|
|
18
|
- The GSM system operates in a burst transmission mode with 124
radio channels in the 900 MHz band, and these bursts can carry different
types of information. The first type of information is speech, which is
coded at 6.5 kbit/s or 13 kbit/s. The second type is data, which can be
sent at 3.6 kbit/s, 6 kbit/s or 12.6kbit/s. These two forms of transmission
are the useful parts of the transmission, but have to be supported by
overhead information which is sent in control channels (CCH).
|
|
19
|
- The use of digital radio transmission and the advanced handover
algorithms between radio cells in GSM network allows for significantly
better frequency usage than in analogue cellular systems, thus
increasing the number of subscribers that can be served. 7
Since8 GSM provides common standard, cellular subscribers
will also be able to use their telephones over the entire GSM service
area. Roaming is fully automatic between and within all countries
covered by GSM system. In addition to international roaming, GSM provides
new services, such as high-speed data communication, Facsimile and short
message service. The GSM technical specifications are designed to work in
concert with other standards, e. g. ISDN. Interworking between the
standards is in this way assured. In the long term perspective cellular
systems, using a digital technology, will become the universal method of
telecommunication.
|
|
20
|
- The third generation mobile communication system currently being
developed9 in Europe is intended to integrate all the
different services of second generation systems and cover a much wider
range of broadband services (voice, data, video and multimedia) consistent
and compatible with technology developments taking place within the
fixed telecommunication networks.
|
|
21
|
- 与本单元课题有关的电信术语或用语
- total access communication system 全接入的通信系统
- global mobile communication system 全球移动通信
- time division multiple access 时分多址
- facsimile and short message service 传真和短消息服务
- fixed communication networks 固定通信网络
- coaxial cable 同轴电缆
- interface conversion 接口转换
- cellular communication principle 蜂窝通信原理
|
|
22
|
- frequency reuse and cell splitting 频率再用和蜂窝裂变
- cochannel interference共信道干扰
- base station transceiver 机站收发信机
- subscriber register用户寄存器
- burst transmission mode突发脉冲传输模式
- overhead information 开销信息
- technical specifications 技术规范
- personal communications 个人通信
- communication standards 通信标准
|
|
23
|
- fixed telephone service 固定电话业务
- network capacity 网络容量
- mobile switching center 移动交换中心
- international roaming 国际漫游
- broadband service 宽带业务
- frequency allocation 频谱分配
- analogue mode 模拟方式
- billing function 收费功能
- handover algorithms 切换算法
|
|
24
|
- i. Review the important expressions , phrases or sentences which were
learnt in the study of text by guiding the students through Exercises
1-2 between Page 120and Page 121 in class .
|
|
25
|
- ii. Ask the students to summarize the translation skills touched upon in
the study of the text.
- Possible answers: 词类转译,长句拆分,增词法。
|
|
26
|
- http://tech.sina.com.cn/t/2006-02-15/0811841277.shtml
- http://tech.sina.com.cn/other/2004-07-08/1516385072.shtml
|
|
27
|
- 1.Preview Unit 11
- 2.Do Exercises3-5 between Page 121-124
|
|
28
|
|
|
29
|
|
|
30
|
|
|
31
|
- 世界范围移动通信的成功标志着通信正在向着更加个人化、更加方便的通信系统迈进。在商务中需使用移动电话的人们很快就认识到在个人生活中随时随地打电话不仅仅带来了方便,而且是一种必需。
|
|
32
|
- 不像固定通信系统,个人通信的快速发展在很大程度上依赖于技术和通信标准的发展。
- 移动通信取得业务腾飞的三个关键因素是费用、手机的大小和重量以及链路的收费和质量。如果其中任何一个不能令人满意,尤其是前两项,移动通信的市场增长就有可能受到严重的限制。
|
|
33
|
- 固定电话业务是全球性的,系统的相互连接采取同轴电缆、光纤甚至卫星。虽然各国标准不同,但却采用共同的接口和接口转换装置,使得相互连接可以进行。对移动通信来说,问题要更加复杂,这是由于需要漫游业务就要有更复杂的网络系统。这样比起固定通信系统,移动通信的标准问题是取得成功更为关键的因素。此外,在移动通信领域,频谱的分配也是令人苦恼的问题。
|
|
34
|
- 移动通信系统最初以模拟方式工作(现在仍在运行),其频带在450
MHz,后来逐步发展到900 MHz的数字GSM系统,下一步是向工作在1 800 MHz的个人通信系统发展。移动通信的发展可分为几代。第一代系统如美国的高级移动电话系统(AMPS)、欧洲多数国家的全接入通信系统(TACS)以及北欧的移动电话系统(NMT),这些都是模拟系统。第二代移动通信系统在很大程度上是由欧洲特别移动小组(GSM)委员会所制订的标准决定的,设计这一系统作为一种全球移动通信系统。
|
|
35
|
- GSM系统基于蜂窝通信系统原则。这一概念是由美国贝尔系统工程师在40年代首先提出来的。这一思想出自于增加网络容量的需要以及解决网络堵塞的问题。在人口稠密地区运行的广播式移动网络系统会由于很少的几个用户同时呼叫而引起堵塞。蜂窝系统的威力在于允许频率的再利用。
|
|
36
|
- 蜂窝概念由两个特点确定,即频率重复利用和小区分割。在相邻覆盖区域相隔足够远而不至于引起共用信道干扰的,通过使用同一频率的无线信道、频率再利用才起作用。这样可以处理同时出现的呼叫并超过了理论频谱容量。当小区的业务需求增到最大时,就要进行小区划区,小区再被分成更小的蜂窝系统区域。蜂窝系统的小区形状常被描绘成六边形,一群六边形小区的数量可以是7个、9个或12个。
- 对于一个充分运营的移动系统来说,GSM系统需要建立一些功能。
|
|
37
|
- 小区的覆盖面由一个基站控制,基站本身由两个单元组成。第一个单元是传输系统,它在实际运行中与移动台进行通信以建立并保持通话。第二个是基站收发信机(BTS),由基站控制器(BSC)控制,而BSC与移动交换中心(MSC)进行通信。这条通信链路,对于MSC与本地公共交换电话网(PSTN)的链接以及连接存储在系统寄存器中的用户数据来说,都十分重要。用户寄存器使GSM系统核查需要使用网络的用户,允许接入并建立收费功能等。
|
|
38
|
- 1978年由世界管理会议(WAC)分配给GSM 900 MHz的部分频带,实际的频带是890~915 MHz用于上行传输,935~960 MHz用于下行传输。接入方式是时分多址(TDMA)方式。
|
|
39
|
- GSM系统以突发脉冲序列传输方式工作。在900 MHz频带有124个无线信道,这些突发脉冲序列可以传送不同的信息。第一类信息是话音,编码速率为6.5
kbit/s或13 kbit/s。第二类信息是数据,可以3.6 kbit/s,6 kbit/s或12.6 kbit/s的速率传输。这两类信息是传输信息的有用部分,但是传输还必须得到额外开销信息的支持,开销信息通过控制信道传输。
|
|
40
|
- GSM网络使用数字无线传输和先进的无线越区切换算法,可以得到比模拟蜂窝系统好得多的频率利用,因而增加了服务的用户数。由于GSM可提供共同的标准,蜂窝用户就可以在整个GSM服务区使用其电话。在GSM覆盖的国内或国际区域内,其漫游是完全自动的。除了国际漫游外,GSM还可提供新型用户服务,如高速数据通信、传真和短电文业务。GSM技术规范可与其他通信标准保持一致,如ISDN。这样可保证标准间的互通。展望未来,利用数字技术的蜂窝系统将成为通信的通用方式。
|
|
41
|
- 目前在欧洲正在开发第三代移动通信系统,其目的是要综合第二代系统的所有不同业务并覆盖更广泛的业务(话音、数据、视频、多媒体)范围,而且还要与固定电信网络的技术发展保持一致和兼容。
|
|
42
|
- 1.标题:GSM(Global System for Mobile Communication)
- GSM是此词组Global System for Mobile Communication的缩写形式,他取了Global System
Mobile三个单词的首字母,译为全球移动通信系统。
|
|
43
|
- 2.The success of mobile systems across the world is a sign that
communication is moving towards a more personalized, convenient system.
- 分析: across the world: throughout the world 全球
- towards:-prep. toward, in the direction of 向…,往….
- 类似的表达: walk toward(s), run toward(s)…..
- that引导定语从句修饰sign.sign是名词,但在译成中文可用动词表达。本句可译为世界范围移动通信的成功标志着......
- 在英译汉过程中, 有些句子可以逐词对译, 有些句子则由于英汉两种语言的表达方式不同,在译文中需要转换词性,才能使译文通顺自然。
- eg. Rockets have found application for the exploration of the universe.
- 火箭已经用来探索宇宙。(名词转译成动词)
- The sight and sound of our jet planes filled me with special longing.
- 看到我们的喷气式飞机,听见机器声,令我特别神往。(名词转译成动词)
|
|
44
|
- 3.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.
- 句子的主语: people
- 句子的谓语: begin to realize
- Who所引导的定语从句修饰句子的主语People,而that引导了一个宾语从句。“the ability to phone”动词不定式to
phone做定语修饰the ability, 打电话的能力。
|
|
45
|
- 4.The speed and rapidity with which the personal communications
revolution takes place is, unlike fixed transmission systems, highly
dependent on technology and communication standards.
- with which引导定语从句修饰句子主语The speed and rapidity,speed 和 rapidity意思一样都表示速度。
- unlike fixed transmission systems是插入语成分。
- take place: 发生
- be dependent on:depend on,依靠,依赖。
|
|
46
|
- 5.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.
- 句子的主语: the three key elements to achieving service take-up译为取得业务腾飞的三个关键因素,to是介词,所以后面接的是动名词achieving. are后面是三个并列的成分作表语。
|
|
47
|
- 6. If any of these are wrong, especially the first two, then market
growth is liable to be severely restricted.
- 分析: liable 是一个形容词,意思是易于。
- eg: He is liable to shout when angry.
- She is liable to bad colds.
- severely: -adv. 严重地, 严厉地
- 7. The fixed telephone service is global and the interconnection varies
from coaxial cable to optical fibre and satellite.
- Vary from …to …使变化, 在......范围内变化。
- eg: Her health varies from good to rather weak.
|
|
48
|
- 8.The national standards are different, but with common interfaces and
interface conversion, interconnection can take place.
- 本句可译为:虽然各国标准不同,但却采用共同的接口和接口转换装置,使得相互连接可以进行。
- 此句采用了增词法,也就是在翻译时按意义上或修辞上以及句法上的需要增加一些词来更忠实通顺地表达原文的思想内容。
|
|
49
|
- 9. For mobile the problem is far more complex, with the need to roam
creating a need for complex networks and systems.
- far more complex在比较级more前加 far表程度,很,比…得多,译为:要复杂得多。with the need to roam
creating a need for complex networks and systems.是分词的独立结构,由介词with引出。
- eg. With the tree growing tall, we get more shade.
- With him well taken care of, we felt quite relieved.
|
|
50
|
- 10. In addition, there is also the vexed question of spectrum allocation
in the mobile area.
- in addition(to): 此外, 除…以外
- vexed question:颇受争议的问题,难题
|
|
51
|
- 11. The history of mobility can split into generations.
- split into: divide into separate parts. 分开,分离
|
|
52
|
- 12.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.
- Nordic –adj.北欧的, 北欧人的. –n.北欧人
- which引导的定语从句修饰前面的句子,可译为这些(AMPS, TACS,NMT)都是模拟系统。
|
|
53
|
- 13.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
- dominate: -vt. have a commanding influence over 支配,管理
- GSM也被称之为欧洲特别移动小组委员会,它取了 group special mobile三个单词的首字母。
- 本句中两次出现了介词by,第一个by意思是according to 根据,依照; 第二个by 引导被动语态的动作执行者。
- set out: 制定;开始做…,着手;出发.
- which引导的定语从句修饰前面句子中的standard。
|
|
54
|
- 14. The GSM system is based on a cellular communications principle
which was first proposed as a concept in the 1940s by Bell System
engineers in the US.
- be based on:以…为基础,以..为根据。
- which引导的定语从句修饰a cellular communications principle。翻译时,注意将句子拆分为两个并列句。
- 译文:GSM系统基于蜂窝通信系统原则。这一概念是由美国贝尔系统工程师在40年代首先提出来的。
- propose : put forward 提出,提议。
- as作介词用,表示作为…
|
|
55
|
- 15.The idea came out of the need to increase network capacity and got
round the fact that broadcast mobile networks, operating in densely
populated areas, could be jammed by a very small number of simultaneous
calls.
- come out of:出自于…,从…中出来
- get round :规避,克服。
- that 引出定语从句修饰fact ,operating in densely populated areas现在分词短语对前面的定语从句的主语broadcast
mobile networks作进一步的说明。
- densely populated areas 人口密集的地区
- a very small number of:很少量的,极少数的
|
|
56
|
- 16. Frequency reuse comes into play by using radio channels on the same
frequency in coverage areas that are far enough apart not to cause
co-channel interference
- come into play:起作用
- by :以…的方式,采用
- that are far enough apart not to cause co-channel interference定语从句修饰coverage
areas
- not to cause co-channel interference这个含否定意义的不定式短语作状语。
- 译文:在相邻覆盖区域相隔足够远而不至于引起共用信道干扰的,通过使用同一频率的无线信道、频率再利用才起作用。
|
|
57
|
- 17. Cell splitting is necessary when the traffic demand on a cell has
reached the maximum and the cell is then divided into a micro-cellular
system.
- When引导时间状语从句
- traffic:(电话的) 通话量,
- divide into: separate into parts(使)分割;分切
- eg.Divide this line into 20equal parts.
|
|
58
|
- 18 The shape of cell in a cellular system is always depicted as a
hexagon and the cluster size can be seven, nine or twelve.
- depict: -vt. represent, describe 描写, 描绘,表达
- cluster: -n. group (人,动物等的)群,团 eg.
a cluster of people
|
|
59
|
- 19. The GSM system requires a number of functions to be created for a
fully operational mobile system.
- a number of: some一些,许多
- create: bring into existence,创造,创立
|
|
60
|
- 18. The cell coverage area is controlled by a base station which
is itself made up of two elements.
- be made up of: 由…组成, 由…构成
- itself: 反身代词, 用来加强语气, 表示“它本身”
|
|
61
|
- 19…which communicates out to the mobile and also receives information
from it to set up and maintain calls when actually in operation.
- set up:建立,成立
- eg. The new government was set up after the war.
- maintain: to continue to have, do.维持,保持
- 为了让译文更为流利本句可以把原文中两个动宾搭配 communicates out to the mobile and also receives
information from it 译为与移动台进行通信
|
|
62
|
- 20.---the essential link to the local public switched telephone network
(PSTN), and to the subscriber data which is stored in registers within
the system.
- essential: -adj. 基本的, 不可缺少的
- 本句在翻译中为了使译文通顺采用了增词法, 增加动词。
- 这条通信链路,对于MSC与本地公共交换电话网(PSTN)的链接以及连接存储在系统寄存器中的用户数据来说,都十分重要。
|
|
63
|
- 21. The GSM system was allocated part of the 900 MHz band at the 1978
World Administration Conference (WAC)…
- at the 1978 World Administration Conference: 1978年的世界管理会议
- …the actual bands being 890 to 915 MHz for the uplink transmission and
935 to 960 MHz for the downlink.
- 此句为分词的独立结构形式,对前面的主句作进一步的说明。
- 独立结构由“名词/代词+V-ing或 V-ed”构成,一般用作句子的状语,表示时间、原因、伴随、方式等。
- Class being over, the children went home.(表时间)
- They had many talks with the native, the guide acting as interpreter.(表伴随)
|
|
64
|
- 22. The GSM system operates in a burst transmission mode with 124
radio channels in the 900 MHz band, and these bursts can carry different
types of information.
- 此句在翻译时注意将其拆分。译文: GSM系统以突发脉冲序列传输方式工作。在900 MHz频带有124个无线信道,这些突发脉冲序列可以传送不同的信息。
|
|
65
|
- 23. These two forms of transmission are the useful parts of the
transmission, but have to be supported by overhead information which is
sent in control channels (CCH).
- which引导定语从句,修饰overhead information, 在翻译时,可将句子译成并列分句。译文:这两类信息是传输信息的有用部分,但是传输还必须得到额外开销信息的支持,开销信息通过控制信道传输。
|
|
66
|
- 27. The GSM technical specifications are designed to work in concert
with other standards, e. g. ISDN.
- in concert : in agreement一致,共同
- eg. The various government decided to act in concert over this matter.
|
|
67
|
- 25.In the long term perspective cellular systems, using a digital
technology, will become the universal method of telecommunication.
- perspective: view, 远景; in the long term perspective展望未来
- 分词短语using a digital technology修饰主语cellular systems。
|
|
68
|
- 26. The third generation mobile communication system currently
being developed9 in Europe is intended to integrate all the different
services of second generation systems and cover a much wider range of
broadband services (voice, data, video and multimedia) consistent and
compatible with technology developments taking place within the fixed
telecommunication networks.
- 句子的主语:The third generation mobile communication system
- being developed作后置定语修饰主语。
- intend to:to plan, to mean to do打算
- much wider:宽得多的
- consistent(with) :一致的,一贯的;
compatible(with): 和谐共处,相容
- consistent and compatible定语后置修饰broadband service。
- 本句句子较长,在翻译的时候注意对句子进行拆分, 使原文的一个句子分译成两个或两个以上的句子。目前在欧洲正在开发第三代移动通信系统,其目的是要综合第二代系统的所有不同业务并覆盖更广泛的业务(话音、数据、视频、多媒体)范围,而且还要与固定电信网络的技术发展保持一致和兼容
。
|