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1、UNIT 21 4G Network UNIT21 4G Network 21-1 Technical Part21-2 Reading Material 第一页，共三十七页。UNIT 21 4G Network 第二页，共三十七页。UNIT 21 4G Network 第三页，共三十七页。UNIT 21 4G Network 21-1 Technical Part 21-1-1 Definition 4G is the fourth generation of cell phone mobile communications standards. It is a successor of t
2、he third generation (3G) standards. A 4G system provides mobile ultra-broadband Internet access, for example to laptops with USB wireless modems, to smartphones, and to other mobile devices. Conceivable applications include amended mobile web access, IP telephony, gaming services, high-definition mo
3、bile TV, video conferencing and 3D television. 第四页，共三十七页。UNIT 21 4G Network Two 4G candidate systems are commercially deployed: The Mobile WiMAX standard (at first in South Korea in 2006), and the first-release Long term evolution (LTE) standard (in Scandinavia since 2009). It has however been debat
4、ed if these first-release versions should be considered as 4G or not. See technical definition. In the U.S. 第五页，共三十七页。UNIT 21 4G Network Sprint Nextel has deployed Mobile WiMAX networks since 2008, and MetroPCS was the first operator to offer LTE service in 2010. USB wireless modems have been availa
5、ble since the start, while WiMAX smartphones have been available since 2010 and LTE smartphones since 2011. Equipment made for different continents are not always compatible, because of different frequency bands. Mobile WiMAX and LTE smartphones are currently (April 2012) not available for the Europ
6、ean market.第六页，共三十七页。UNIT 21 4G Network 21-1-2 Introductions 1. Origin of LTEIn March 2008, the International Telecommunications Union-Radio communications sector (ITU-R) specified a set of requirements for 4G standards, named the International Mobile Telecommunications Advanced (IMT-Advanced) speci
7、fication, setting peak speed requirements for 4G service at 100 megabits per second (Mbit/s) for high mobility communication (such as from trains and cars) and 1 gigabit per second (Gbit/s) for low mobility communication (such as pedestrians and stationary users). 第七页，共三十七页。UNIT 21 4G Network Since
8、the above mentioned first-release versions of Mobile WiMAX and LTE support much less than 1 Gbit/s peak bit rate, they are not fully IMT-Advanced compliant, but are often branded 4G by service providers. On December 6, 2010, ITU-R recognized that these two technologies, as well as other beyond-3G te
9、chnologies that do not fulfill the IMT-Advanced requirements, could nevertheless be considered“4G”, provided they represent forerunners to IMT-Advanced compliant versions and“a substantial level of improvement in performance and capabilities with respect to the initial third generation systems now d
10、eployed”.第八页，共三十七页。UNIT 21 4G Network Mobile WiMAX Release 2 (also known as WirelessMAN-Advanced or IEEE 802.16m) and LTE Advanced (LTE-A) are IMT-Advanced compliant backwards compatible versions of the above two systems, standardized during the spring 2011, and promising peak bit rates in the order
11、 of 1 Gbit/s. Services are expected in 2013. 第九页，共三十七页。UNIT 21 4G Network As opposed to earlier generations, a 4G system does not support traditional circuit-switched telephony service, but all-internet protocol (IP) based communication such as IP telephony. As seen below, the spread spectrum radio
12、technology used in 3G systems, is abandoned in all 4G candidate systems and replaced by OFDMA multi-carrier transmission and other frequency-domain equalization (FDE) schemes, making it possible to transfer very high bit rates despite extensive multi-path radio propagation (echoes). The peak bit rat
13、e is further improved by smart antenna arrays for multiple-input multiple-output (MIMO) communications. 第十页，共三十七页。UNIT 21 4G Network 2LTE AdvancedLTE Advanced (Long-term-evolution Advanced) is a candidate for IMT-Advanced standard, formally submitted by the 3GPP organization to ITU-T in the fall 200
14、9, and expected to be released in 2012. The target of 3GPP LTE Advanced is to reach and surpass the ITU requirements. 第十一页，共三十七页。UNIT 21 4G Network LTE Advanced is essentially an enhancement to LTE. It is not a new technology but rather an improvement on the existing LTE network. This upgrade path m
15、akes it more cost effective for vendors to offer LTE and then upgrade to LTE Advanced which is similar to the upgrade from WCDMA to HSPA. LTE and LTE Advanced will also make use of additional spectrum and multiplexing to allow it to achieve higher data speeds. Coordinated Multi-point Transmission wi
16、ll also allow more system capacity to help handle the enhanced data speeds. Release 10 of LTE is expected to achieve the LTE Advanced speeds. Release 8 currently supports up to 300 Mbit/s download speeds which is still short of the IMT-Advanced standards.第十二页，共三十七页。UNIT 21 4G Network 3. Development
17、of Long Term Evolution (LTE)The pre-4G technology 3GPP Long Term Evolution (LTE) is often branded“4G-LTE”, but the first LTE release does not fully comply with the IMT-Advanced requirements. LTE has a theoretical net bit rate capacity of up to 100 Mbit/s in the downlink and 50 Mbit/s in the uplink i
18、f a 20 MHz channel is used and more if multiple-input multiple-output (MIMO), i.e. antenna arrays, are used.The below Figure 21-1 shows the 4G wireless devices. 第十三页，共三十七页。UNIT 21 4G Network Figure 21-1 4G wireless devices第十四页，共三十七页。UNIT 21 4G Network The physical radio interface was at an early sta
19、ge named High Speed OFDM Packet Access (HSOPA), now named Evolved UMTS Terrestrial Radio Access (E-UTRA). The first LTE USB dongles do not support any other radio interface. 第十五页，共三十七页。UNIT 21 4G Network The worlds first publicly available LTE service was opened in the two Scandinavian capitals Stoc
20、kholm (Ericsson and Nokia Siemens Networks systems) and Oslo (a Huawei system) on 14 December 2009, and branded 4G. The user terminals were manufactured by Samsung. Currently, the three publicly available LTE services in the United States are provided by MetroPCS, Verizon Wireless, and AT&T. As of A
21、pril 2012, US Cellular also offers 4G LTE. Sprint Nextel has also stated its considering switching from WiMAX to LTE in the near future. 第十六页，共三十七页。UNIT 21 4G Network 4. Mobile WiMAX (IEEE 802.16e)The Mobile WiMAX (IEEE 802.16e-2005) mobile wireless broadband access (MWBA) standard (also known as Wi
22、Bro in South Korea) is sometimes branded 4G, and offers peak data rates of 128 Mbit/s downlink and 56 Mbit/s uplink over 20 MHz wide channels. 第十七页，共三十七页。UNIT 21 4G Network In June 2006, the worlds first commercial mobile WiMAX service was opened by KT in Seoul, South Korea. Sprint Nextel has begun
23、using Mobile WiMAX, as of September 29, 2008 branded as a“4G”network even though the current version does not fulfil the IMT Advanced requirements on 4G systems. 第十八页，共三十七页。UNIT 21 4G Network 21-1-3 Application Case or Example Application: The coexistence of LTE and GSM/UMTSLTE is not standalone, bu
24、t co-exist/interworks with GSM/UMTS.The current radio access networks are separated. In the future, GSM/UMTS/LTE will tend to be converged into one network. However, this process will last at least 10 years. During this stage, 5-band 3-mode will co-exist on one site and interwork with each other to
25、provide end users consistence experience for a long time. Therefore, LTE is not standalone, but co-exists & interworks with GSM/UMTS networks. 第十九页，共三十七页。UNIT 21 4G Network The key requirements for this network modernization procedure are as below: Multi-Technology co-exists at least 10 years; up to
26、 5 frequencies per site One single platform to support GSM/UMTS/LTE and FDD/TDD simultaneously The platform: common HW & upgradeable SW for convergence & evolution第二十页，共三十七页。UNIT 21 4G Network One utility set: Co-RRM, Co-TRM, Co-OAM, Co-RNP/RNO, Co-Site/Antenna/Feeder The combination of radio wirele
27、ss equipment frequency The below slide (Figure 21-2) shows the transformation and evolution from the current GSM/3G network to LTE/4G network. 第二十一页，共三十七页。UNIT 21 4G Network Figure 21-2 Evolution of 2G/3G to 4G第二十二页，共三十七页。UNIT 21 4G Network 21-2 Reading Material 21-2-1 Reading Comprehension The Path
28、 to 4G Will Take Many TurnsA race is going on right now and its a heated one. Its a race to the next generation of untethered communications4G mobile broadband wireless. The prize for reaching the finish line first or even finishing at all could be huge. 第二十三页，共三十七页。UNIT 21 4G Network Yet that finis
29、h line keeps moving, as the fourth generation (4G) isnt yet fully defined. In fact, spectrum wont be allocated until 2007. Standards probably wont be complete until the year after that. Right now, thought, many teams across the globe are investing a lot of time, effort, money, and talent to make sur
30、e that they are in the race.第二十四页，共三十七页。UNIT 21 4G Network Any road race has three basic fundamentals: a track, a car, and a crew. The worldwide effort to develop 4G system and devices could be considered a race. Just as the track itself sets the boundary conditions for the race, standards set the b
31、oundaries for telecommunications.第二十五页，共三十七页。UNIT 21 4G Network The first topic of this article is standards development for 4G, which ranges from the International Telecommunications Union (ITU) to national and regional standards development organizations (SDOs). The people who are tolling away day
32、 in and day out to make sure their team wins the race-the“pit crew”of 4G research are the engineers working in industry partnerships, high-tech corporations, and university research labs. The second section of this article will focus on their efforts. 第二十六页，共三十七页。UNIT 21 4G Network Lastly, every tea
33、m needs a vehicle to propel them to the final goalthe finish line. In the race to 4G, the race cars are the underlying technologies that enable communications to be more seamless, useful, and powerful. 第二十七页，共三十七页。UNIT 21 4G Network Words & Expressionsuntethered communications 无线通信 broadband n. 宽带sp
34、ectrum n. 波谱(bp)；范围，系列 allocate vt. 分配，分派invest vt&vi. 投资，花费 fundamental n. 基本原则，基本法则crew n. 一队(或一组)工作人员 第二十八页，共三十七页。UNIT 21 4G Network boundary n. 分界线；界限，范围telecommunication 电信(dinxn)International Telecommunications Union 国际电信(dinxn)联盟 toil away 长时间辛苦的工作 corporation n. 公司vehicle n. 交通工具，车辆；传播媒介，手段
35、propel vt. 推进，推动seamless adj. 准确无误的，完全符合逻辑第二十九页，共三十七页。UNIT 21 4G Network 21-2-2 Exercises I. Multiple Choices.1. According to the passage, the spectrum will be allocated by the year of _.A. 2006 B. 2007 C. 2008 D. 2009第三十页，共三十七页。UNIT 21 4G Network 2. According to the 2nd Paragraph, it is essential f
36、or a real road race to have_.A. a track, a car and a bounfaryB. a track, a car and a standardC. a track, a crew and a bounfaryD. a track, a crew and a crew第三十一页，共三十七页。UNIT 21 4G Network 3. It can be learned from the passage that, the“ITU (Para.3)”refer to _.A. International Technology UnionB. Intern
37、ational Telecommunications UnitC. International Telephones UnionD. International Telecommunications Union第三十二页，共三十七页。UNIT 21 4G Network 4. What does the“pit crew”mean according to the passage?A. The engineers. B. The seaman.C. The racres. D. The corporations.第三十三页，共三十七页。UNIT 21 4G Network 5. It can
38、be learned from the passage that the last section of this article will mainly _.A. discuss some new races related to 4GB. examine the types of the application of 4GC. discuss some major technologies involved in the raceD. examine different between 4G races and real races第三十四页，共三十七页。UNIT 21 4G Networ
39、k II. Read & Translate.1. Right now, thought, many teams across the globe are investing a lot of time, effort, money, and talent to make sure that they are in the race.2. The people who are tolling away day in and day out to make sure their team wins the race-the“pit crew”of 4G research-are the engi
40、neers working in industry partnerships, high-tech corporations, and university research labs.第三十五页，共三十七页。UNIT 21 4G Network 3. In the race to 4G, the race cars are the underlying technologies that enable communications to be more seamless, useful, and powerful.第三十六页，共三十七页。内容(nirng)总结UNIT21 4G Network第三十七页，共三十七页。