最新IT专业英语UNIT19 3G Network(共45张PPT课件).pptx

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1、UNIT 19 3G Network UNIT19 3G Network 19-1 Technical Part19-2 Reading Material 第一页，共四十五页。UNIT 19 3G Network 第二页，共四十五页。UNIT 19 3G Network 第三页，共四十五页。UNIT 19 3G Network 19-1 Technical Part 19-1-1 Definition 3G or 3rd generation mobile telecommunications is a generation of standards for mobile phones and

2、 mobile telecommunication services fulfilling the International Mobile Telecommunications- 2000 (IMT-2000) specifications by the International Telecommunication Union. Application services include wide-area wireless voice telephone, mobile Internet access, video calls and mobile TV, all in a mobile

3、environment.第四页，共四十五页。UNIT 19 3G Network 19-1-2 Introductions Several telecommunications companies market have extended to wireless mobile Internet services as 3G, indicating that the advertised service is provided over a 3G wireless network. Services advertised as 3G are required to meet IMT-2000 t

4、echnical standards, including standards for reliability and speed (data transfer rates). 第五页，共四十五页。UNIT 19 3G Network To meet the IMT-2000 standards, a system is required to provide peak data rates of at least 200 kbit/s (about 0.2 Mbit/s). However, many services advertised as 3G provide higher spee

5、d than the minimum technical requirements for a 3G service. Recent 3G releases, often denoted 3.5G and 3.75G, also provide mobile broadband access of several Mbit/s to smartphones and mobile modems in laptop computers.第六页，共四十五页。UNIT 19 3G Network 1. Concept of UMTS The UMTS(Universal Mobile Telecomm

6、unications System) first offered in 2001, standardized by 3GPP, used primarily in Europe, Japan, China (however with a different radio interface) and other regions predominated by GSM 2G system infrastructure. The cell phones are typically UMTS and GSM hybrids. Several radio interfaces are offered,

7、sharing the same infrastructure: The latest UMTS release, HSPA+, can provide peak data rates up to 56 Mbit/s in the downlink in theory (28 Mbit/s in existing services) and 22 Mbit/s in the uplink. The following standards are typically branded 3G:第七页，共四十五页。UNIT 19 3G Network The TD-SCDMA(Time Divisio

8、n Duplex Synchronous Code Division Multiple Access) radio interface was commercialized in 2009 and is only offered in China. The system bandwidth is 1.6MHz, chip rate is 1.28Mbps. TD-SCDMA is an important feature of 3GPP R4 standards and admitted to the UTRA TDD standard by 3GPP in 1999.第八页，共四十五页。UN

9、IT 19 3G Network The original and most widespread radio interface is called W-CDMA (Wideband Code Division Multiple Access). The system bandwidth is 5MHz, chip rate is 3.84Mbps. The Figure 19-1 shows the network architecture of WCDMA.第九页，共四十五页。UNIT 19 3G Network Figure 19-1 The network architecture

10、of WCDMA telecommunications industry第十页，共四十五页。UNIT 19 3G Network The CDMA2000 system, first offered in 2002, standardized by 3GPP2, used especially in North America and South Korea, sharing infrastructure with the IS-95 2G standard. The cell phones are typically CDMA2000 and IS-95 hybrids. The lates

11、t release EVDO Rev B offers peak rates of 14.7 Mbit/s downstream. The Figure 19-2 shows the deployment of CDMA2000 1X EVDO.第十一页，共四十五页。UNIT 19 3G Network Figure 19-2 Network deployment of CDMA 2000 1X EVDO第十二页，共四十五页。UNIT 19 3G Network The above systems and radio interfaces are based on spread spectru

12、m radio transmission technology. While the GSM EDGE standard (“2.9G”), DECT(Digital Enhanced Cordless Telecommunication) cordless phones and Mobile WiMAX standards formally also fulfill the IMT-2000 requirements and are approved as 3G standards by ITU, these are typically not branded 3G, and are bas

13、ed on completely different technologies第十三页，共四十五页。UNIT 19 3G Network 2. Introductions of TD-SCDMATD-SCDMA standard, developed by the China independently, has become one of the three mainstream 3G, and has an important position in China or even in international, TD-SCDMA uses TDD, smart antenna, join

14、t detection, dynamic channel allocation, uplink synchronization, baton handover and other key technologies. All of these have TF-SCDMA system performance been greatly improved, the following will describe each of the key technology of TD-SCDMA.第十四页，共四十五页。UNIT 19 3G Network Introductions to TDD3G sys

15、tem is divided into time division duplex (TDD) and frequency division duplex (FDD) modes. FDD is used in WCDMA and CDMA2000, datas receiving and transmission occur in two symmetric, separated frequency channel. TDD is used in TD-SCDMA, which means the receiving and transmission occur in the same fre

16、quency. 第十五页，共四十五页。UNIT 19 3G Network Through periodic conversion direction, alternation uplink and downlink transmission in the same carrier, with a guaranteed time to separate the receiving and transmission channel. TD-SCDMA system is divided into the Core Network, Radio Access Network and User Eq

17、uipment from the functions. The design combine with FDMA, TDMA, CDMA and SDMA as a whole, has high spectrum efficiency and low emission power. 第十六页，共四十五页。UNIT 19 3G Network The uplink and downlink can be asymmetric is also its advantage. TD-SCDMA maintain backward compatibility with GSM, which is th

18、e second generation mobile communication system cur widely used in China and the world, allowing smooth transition from GSM to 3G systems.第十七页，共四十五页。UNIT 19 3G Network Advantage of TDD:1) No symmetric band. It can use the asymmetric band flexibly which FDD cant use.It can adjust the number of up and

19、 down time slots to support asymmetric data sevices.2) Uplink and downlink has the same frequency, so the propagation characteristics can be considered the same under certain conditions. Its beneficial using smart antennas and other new technologies.3) Equipment costs are generally lower than the FD

20、D system.第十八页，共四十五页。UNIT 19 3G Network 3. Advantages and disadvantages of TD-SCDMA Advantages 1) High spectrum efficiency, TD-SCDMA uses TDD mode, applicate FDMA, CDMA, TDMA multiple access technologies synthetically, to facilitate set uplingk and downlink switch point in the transmission for differ

21、ent kinds of services, thus increasing spectrum efficiency.第十九页，共四十五页。UNIT 19 3G Network 2) Support a variety of communication interfaces: TD-SCDMA meet a variety of interference requirement s include lub,A,Gb,Iu,IuR. Base station subsystem can be both as a expansion of 2G, 2.5G GSM and a base stati

22、on subsystem of 3G.第二十页，共四十五页。UNIT 19 3G Network 3) Spectrum flexibility: TD-SCDMA has a flexible frequency spectrum. Only a band of 1.6M can provide the service of 3G with 2M speed, which is very ideal for the transmission of asymmetric operations.4) System performance stable: TD-SCDMA is more suit

23、able for the emerging smart antenna technology and joint detection technology. All of these technologies can reduce interference and increase the stability of system.第二十一页，共四十五页。UNIT 19 3G Network 5) Compatibility with legacy systems: It adapt to a variety of UEs(User Equipment) of the environment,

24、can implement a smooth transition from existing communications system to the next generation mobile communication system.第二十二页，共四十五页。UNIT 19 3G Network Disadvantage1) TD-SCDMA is falling behind WCDMA and CDMA2000 in commercial progress, technological development and industrial scale. TD-SCDMA has a

25、narrow bandwidth and can not take full advantage of multipath, which reduce the system efficiency.2) Ability in high-speed mobile environment is falling behind WCDMA and CDMA2000.3) TD-SCDMA system requires district keep synchronously, which need precise timing. So there is a high requirement on the

26、 timing system.第二十三页，共四十五页。UNIT 19 3G Network 19-1-3 Application Case or Example 1. Case 1: Application in stream media serviceWCDMA equipment supporting stream media business, which supports the standard RTP/RTCP protocol, provides the high performance adaptive bandwidth and the industrys widely us

27、ed MPEG-2/4 technologies, also applied to audio, video codec, and provide a wealth of operational interface, access to various types of media. 第二十四页，共四十五页。UNIT 19 3G Network It can support unicast, multicast service and variety charging policy with stream media technology, providing a complete digit

28、al rights management. Figure 19-3 shows logical network diagram of stream media as below.第二十五页，共四十五页。UNIT 19 3G Network Figure 19-3 Logical network diagram of stream media第二十六页，共四十五页。UNIT 19 3G Network HTTP Accelerator: Web browsing is the most widely used data service. Users expect to be able to qu

29、ickly load web pages at any time or place. In traditional mobile telecommunication systems, however, multiple services coexist and equally compete for limited bandwidth resources. Bandwidth is not allocated preferentially to web page access, making it difficult for users to enjoy high-quality, low-d

30、elay web browsing. During high-traffic hours, web access is frequently impacted by other services and users experience high levels of delay.第二十七页，共四十五页。UNIT 19 3G Network This feature relies on packet analysis to recognize web page accesses and then preferentially allocates higher bandwidth to these

31、 services, thus reducing access time and improving the user experience. This feature is only applicable for HSDPA users. 第二十八页，共四十五页。UNIT 19 3G Network P2P Slow down: With the current rapid growth of high bandwidth mobile telecommunication systems, more and more users are using P2P to download conte

32、nt such as music and videos. Due to its high volume and long duration, P2P traffic consumes a large amount of system resources. This significantly increases operator costs and adversely affects the user experience of other time sensitive services. Therefore, to solve this problem, this feature is in

33、troduced. 第二十九页，共四十五页。UNIT 19 3G Network The below Figure 19-4 shows the HTTP Accelerator and P2P Download Rate Restriction.This feature restricts P2P traffic during busy periods, reducing operator cost and improving the user experience of other time sensitive services. High-speed P2P downloads are

34、not restricted during idle periods, which allows P2P users to achieve good performance and helps users take advantage of network resources.第三十页，共四十五页。UNIT 19 3G Network Figure 19-4 HTTP Accelerator and P2P Download Rate Restriction第三十一页，共四十五页。UNIT 19 3G Network 19-2 Reading Material 19-2-1 Reading C

35、omprehension Introduction to 3GThe International Telecommunications Union (ITU) defined the third generation (3G) of mobile telephony standards IMT-2000 to facilitate growth, increase bandwidth, and support more devices applications. For example, GSM (the current most popular cellular phone standard

36、) could deliver not only voice, but also circuit-switched data at download speeds up to14.4 kbps. But to support mobile multimedia applications, 3G had to deliver packet-switched data with better spectral efficiency, at far greater speeds.第三十二页，共四十五页。UNIT 19 3G Network International Mobile Telecommu

37、nications-2000 (IMT-2000), better as 3G or 3rd Generation, is a family of standards for wireless communications defined by the International Telecommunications Union, which includes GSM EDGE, UMTS, and CDMA2000 as well as DECT and WiMAX. Services include wide-area wireless voice telephone, video cal

38、ls, and wireless data, all in a mobile environment.Compared to 2G and 2.5G services, 3G allows simultaneous use of speech and data services and higher data rates (up to 14.4 Mbit/s on the downlink and 5.8 Mbit/s on the uplink with HSPA+). 第三十三页，共四十五页。UNIT 19 3G Network Thus, 3G networks enable netwo

39、rk operators to offer users a wider range of more advanced services while achieving greater network capacity through improved spectral efficiency.Both 3GPP and 3GPP2 are currently working on further extensions to 3G standards, named Long Term Evolution and Ultra Mobile Broadband, respectively. Being

40、 based on an all-IP network infrastructure and using advanced wireless technologies such as MIMO, 第三十四页，共四十五页。UNIT 19 3G Network these specifications already display features characteristic for IMT-Advanced (4G), the successor of 3G. However, falling short of the speed requirements for 4G (which is

41、1 Gbit/s for stationary and 100 Mbit/s for mobile operation), these standards are classified as 3.9G or Pre-4G.3GPP plans to meet th 4G goals with LTE Advanced, whereas Qualcomm has halted development of UMB in favour of the LTE family.第三十五页，共四十五页。UNIT 19 3G Network Words & ExpressionsInternational

42、Telecommunications Union 国际电信联盟facility vt. 使便利(binl)，减轻的困难GSM 全球移动通信系统，俗称全球通 EDGE 是一种基于GAM/GPRS网络的数据增强型移动通信技术，通常被称为“2.75代技术”UMTS 通用移动通信技术CDMA2000 一种3G移动通信标准第三十六页，共四十五页。UNIT 19 3G Network DECT 先进数字式无线通信系统WiMAX 微波存取全球互通，是一项新型(xnxng)的宽带无线接入技术simultaneous adj. 同时发生的，同时存在的 uplink 向上传输HSPA+ 是HSPA(3GPPR6)

43、的向下演进版本，是上下行能力增强的技术第三十七页，共四十五页。UNIT 19 3G Network UMB 是CDMA2000系列标准的演进升级(shng j)版本LTE 3GPP长期演进(LTE)项目，被看做准4G 标准infrastructure n. 基础设施，基础结构MIMO 多输入多输出技术halt vt&vi. 使停下来第三十八页，共四十五页。UNIT 19 3G Network 19-2-2 Exercises I. Multiple Choices.1. According to the passage, 3G refers to _.A. 3 gamesB. 3 grades

44、C. 3 generationsD. 3nd generations第三十九页，共四十五页。UNIT 19 3G Network 2. About 3G, which of the following is NOT TRUE?A. 3G is better known as International Mobile Telecommunications-2000 (IMT-2000).B. 3G allows simultaneous use of speech and data services and higher data rates.C. 3G is a family of stand

45、ards for wireless communications defined by the International Telecommunication Union.D. 3G will have its successors.第四十页，共四十五页。UNIT 19 3G Network 3. How many services are mentioned in a mobile environment?A. Two. B. Three. C. Four. D. Five.4. Which of the following terms is not mentioned in the pas

46、sage?A. 2G. B. 3G. C. 3G. D. 4G.第四十一页，共四十五页。UNIT 19 3G Network 5. What can be inferred from the passage about 4G?A. It is more popular than 3G.B. It will completely replace 3G in the near future.C. It is the most advantaged generation.D. It will be more advanced than 3G.第四十二页，共四十五页。UNIT 19 3G Networ

47、k II. Read & Translate.1. The International Telecommunications Union (ITU) defined the third generation (3G) of mobile telephony standards IMT-2000 to facilitate growth, increase bandwidth, and support more devices applications第四十三页，共四十五页。UNIT 19 3G Network 2. Thus, 3G networks enable network operat

48、ors to offer users a wider range of more advanced services while achieving greater network capacity through improved spectral efficiency.3. Being based on an all-IP network infrastructure and using advanced wireless technologies such as MIMO, these specifications already display features characteristic for IMT-Advanced (4G), the successor of 3G. 第四十四页，共四十五页。内容(nirng)总结UNIT19 3G Network第四十五页，共四十五页。