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【速搜问答】宽带码分多址是什么

问答 admin 3年前 (2020-07-14) 565次浏览 已收录 0个评论

汉英对照:
Chinese-English Translation:

宽带码分多址(W-CDMA)是一种3G蜂窝网络,使用的部分协议与2G GSM标准一致。具体一点来说,W-CDMA是一种利用码分多址复用(或者CDMA 通用 复用技术,不是指CDMA标准)方法的宽带扩频3G移动通信空中接口。 宽带码分多址(英语:Wideband Code Division Multiple Access,常简写为 W-CDMA)是一种 3G 蜂窝网络,使用的部分协议与 2G GSM 标准一致。具体一点来说,W-CDMA 是一种利用码分多址复用(或者 CDMA 通用 复用技术,不是指 CDMA 标准)方法的宽带扩频 3G 移动通信空中接口。

Wideband code division multiple access (W-CDMA) is a kind of 3G cellular network. Some protocols used are consistent with 2G GSM standard. To be specific, W-CDMA is a kind of air interface of broadband spread spectrum 3G mobile communication using code division multiple access multiplexing (or CDMA general multiplexing technology, not referring to CDMA standard). Wideband code division multiple access (W-CDMA) is a kind of 3G cellular network. Some protocols used are consistent with 2G GSM standard. To be specific, W-CDMA is a kind of air interface of broadband spread spectrum 3G mobile communication using code division multiple access multiplexing (or CDMA general multiplexing technology, not referring to CDMA standard).

WCDMA 主要起源于欧洲和日本的早期第三代无线研究活动,GSM 的巨大成功对第三代系统在欧洲的标准化产生重大影响。欧洲于 1988 年开展 RACEⅠ(欧洲先进通信技术的研究)程序,并一直延续到 1992 年 6 月,它代表了第三代无线研究活动的开始。1992-1995 年之间欧洲开始了 RACEⅡ程序。ACTS(先进通信技术和业务)建立于 1995 年底,为 UMTS(通用移动通信系统)建议了 FRAMES(未来无线宽带多址接入系统)方案。在这些早期研究中,对各种不同的接入技术包括 TDMA、CDMA、OFDM 等进行了实验和评估。为 WCDMA 奠定了技术基础。

WCDMA mainly originated from the early 3G wireless research activities in Europe and Japan. The great success of GSM has a great impact on the standardization of 3G system in Europe. The race I program was launched in Europe in 1988 and continued until June 1992. It represents the beginning of the third generation of wireless research activities. Between 1992 and 1995, race II program began in Europe. Acts (advanced communication technology and service) was established at the end of 1995, and proposed frames (future wireless broadband multiple access system) scheme for UMTS (universal mobile communication system). In these early studies, various access technologies including TDMA, CDMA, OFDM are tested and evaluated. It lays a technical foundation for WCDMA.

作为一项新兴技术,WCDMA 也是基于 CDMA 技术的实践和应用衍生。 WCDMA 正迅速风靡全球并已占据 80%的无线市场。截至 2013 年,全球 WCDMA 用户已超过 36 亿,遍布 170 个国家的 156 家运营商已经商用 3GWCDMA 业务。

As an emerging technology, WCDMA is also based on the practice and application of CDMA technology. WCDMA is rapidly becoming popular all over the world and has occupied 80% of the wireless market. As of 2013, there are more than 3.6 billion WCDMA users in the world, and 156 operators in 170 countries have commercial 3G WCDMA services.

历史概要

Summary of history

历史上,欧洲电信标准委员会(ETSI)在 GSM 之后就开始研究其 3G 标准,其中有几种备选方案是基于直接串行扩频码分多址的,而日本的第三代研究也是使用宽带码分多址技术的,其后以二者为主导进行融合,在 3GPP 组织中发展成了第三代移动通信系统 UMTS,并提交给国际电信联盟(ITU-T)。

In history, the European Telecommunication Standards Committee (ETSI) began to study its 3G standard after GSM. Several alternatives were based on direct serial spread spectrum code division multiple access (DSSS-CDMA), while the third generation research in Japan also used broadband code division multiple access technology. Later, the two technologies were integrated and developed into the third generation mobile communication system in 3GPP organization UMTS and submitted to the International Telecommunication Union (ITU-T).

国际电信联盟最终接受 W-CDMA 作为 IMT-20003G 标准的一部分。

The International Telecommunication Union finally accepted W-CDMA as a part of imt-20003g standard.

WCDMA 介绍

WCDMA introduction

WidebandCodeDivision Multiple Access,即 WCDMA.

Wideband CodeDivision multiple access (WCDMA)

摘要:本文主要分析了 WCDMA 主要技术特点、发展现状和未来网络演进的方向。分别介绍了 WCDMA 技术在不同阶段的具体特征和相互演进的方法,介绍了 WCDMA 未来面临的市场和主要业务方向。涉及 WCDMA 实现的关键技术包括射频、中频、基带的 RAKE 处理技术和 Turbo 编解码技术,论述了不同技术的实现难点,最后介绍了增强技术多用户检测和智能天线技术的原理。

Abstract: This paper mainly analyzes the main technical characteristics, development status and future network evolution direction of WCDMA. This paper introduces the specific characteristics and mutual evolution methods of WCDMA technology in different stages, and introduces the future market and main business direction of WCDMA. The key technologies of WCDMA implementation include rake processing technology of RF, if and baseband and and turbo coding and decoding technology. The implementation difficulties of different technologies are discussed. Finally, the principles of enhanced multi-user detection and smart antenna technology are introduced.

Keywords:MobileCommunication,WCDMA,Radio Access Network,The Third Generation Partnership Project

Keywords:MobileCommunication,WCDMA,Radio Access Network,The Third Generation Partnership Project

Abstract:Thepaperpresentsthe main technologies,current situation and evolution of WCDMA. The key features and evolution process during several phases of WCDMA are also discussed. The future services and markets that will be occupied by the WCDMA system are involved. At last the key implementation issues, handicaps and enhanced technologies in WCDMA receiver are also introduced.

Abstract:Thepaperpresentsthe main technologies,current situation and evolution of WCDMA. The key features and evolution process during several phases of WCDMA are also discussed. The future services and markets that will be occupied by the WCDMA system are involved. At last the key implementation issues, handicaps and enhanced technologies in WCDMA receiver are also introduced.

第三代移动通信系统(也称 3G)是移动通信市场经历了第一代模拟技术的移动通信业务的引入,在第二代数字移动通信市场的蓬勃发展中被引入日程的。在当今 Internet 数据业务不断升温中,在固定接入速率(HDSL、ADSL、VDSL)不断提升的背景下,第三代移动通信系统也看到了市场的曙光,益发为电信运营商、通信设备制造商和普通用户所关注。

The third generation mobile communication system (also known as 3G) is introduced into the mobile communication market after the introduction of the first generation analog technology in the mobile communication market. In today’s Internet data business continues to rise, in the background of constant increase in fixed access rate (HDSL, ADSL, VDSL), the third generation mobile communication system has also seen the dawn of the market, becoming increasingly concerned by telecom operators, communication equipment manufacturers and ordinary users.

移动通信技术开始是各自发展的状态,各个国家、技术组织都不断发展自己的技术,美国有 AMPS、D-AMPS、IS-136、IS-95,日本有 PHS、PDC,欧洲则是 GSM。这种格局一方面在移动通信发展的初期满足了用户的需求,开拓了移动通信市场,另一方面也人为造成地区间的隔离,引发了全球统一移动通信制式的需求。ITU 正是在这个背景下于 1985 年启动了第三代移动通信系统的规范工作。

At the beginning, mobile communication technology is in its own development state, and various countries and technical organizations are constantly developing their own technologies. The United States has amps, D-AMPS, IS-136, IS-95, Japan has PHS, PDC, and Europe is GSM. On the one hand, this pattern met the needs of users and opened up the mobile communication market in the early stage of the development of mobile communication. On the other hand, it also artificially caused regional isolation, which led to the demand of global unified mobile communication system. It is in this context that ITU started the standardization of the third generation mobile communication system in 1985.

在第三代移动通信规范提案的概念评估过程中,宽带码分多址(WCDMA)技术以其自身的技术优势成为 3G 的主流技术之一。这里主要介绍 WCDMA 起源、面临的移动通信市场和业务状况、WCDMA 技术特点、发展现状和演进方向。

In the process of concept evaluation of the third generation mobile communication specification proposal, wideband code division multiple access (WCDMA) technology has become one of the mainstream technologies of 3G with its own technical advantages. This paper mainly introduces the origin of WCDMA, the mobile communication market and business situation, the technical characteristics, development status and evolution direction of WCDMA.

技术特征

technical characteristics

只列出部分关键特征

Only some key features are listed

无线通信占用 5MHz 带宽

Wireless communication occupies 5MHz bandwidth

码率是 3.84MChips

The bit rate is 3.84mchips

支持的复用模式:FDD、TDD

Supported reuse modes: FDD, TDD

高速传输以支持多媒体业务

High speed transmission to support multimedia services

室内环境至少 2Mbit/s

Indoor environment at least 2Mbit / S

室外步行环境至少 384Kbit/s

Outdoor walking environment at least 384kbit / S

室外车辆环境至少 144Kbit/s

Outdoor vehicle environment at least 144kbit / S

误解

misunderstand

W-CDMA 名字跟 CDMA 很相近,同时 W-CDMA 跟 CDMA 关系也很微妙。两者都基于码分多址技术,都使用了美国高通(Qualcomm)的部分专利技术。一般认为 W-CDMA 的提出是部分厂商为了绕开专利陷阱而开发的,其方案已经尽可能地避开高通专利。

The name of W-CDMA is very similar to CDMA, and the relationship between W-CDMA and CDMA is also very subtle. Both of them are based on code division multiple access (CDMA) technology, and both use part of the patented technology of Qualcomm. It is generally believed that the proposal of W-CDMA is developed by some manufacturers in order to avoid the patent trap, and its scheme has avoided the high pass patent as much as possible.

在移动电话领域,术语 CDMA 指代属于第二代移动电话的几种相关技术,包括码分多址扩频复用技术,以及美国高通(Qualcomm)开发的包括 cdmaOne(IS-95)和 CDMA2000(IS-2000)的 CDMA 标准族。

In the field of mobile phones, the term CDMA refers to several related technologies belonging to the second generation of mobile phones, including code division multiple access (CDMA) spread spectrum multiplexing technology, and CDMA standard family including cdmaOne (IS-95) and CDMA2000 (IS-2000) developed by Qualcomm.

在 Qualcomm 为 IS-95 协议使用它之前,CDMA 复用技术已经存在了很长时间。然而,由于采用 CDMA 复用方法是 IS-95 协议区别于当时的 GSM(采用 TDMA)等其它协议的主要特征,现在通常将该协议也称为 CDMA。

CDMA multiplexing technology has existed for a long time before Qualcomm uses it for IS-95 protocol. However, CDMA multiplexing is the main feature of IS-95 protocol, which is different from GSM (TDMA) and other protocols at that time.

W-CDMA 属于第三代移动电话技术,它也使用 CDMA 的复用技术而且它跟 Qualcomm 的标准也很相似。但是 W-CDMA 不仅仅是复用标准。它是一个详细的定义移动电话怎样跟基站通讯,信号怎样调制,数据帧怎么构建等的完整的规范集。

W-CDMA belongs to the third generation mobile phone technology. It also uses CDMA multiplexing technology, and it is similar to the standard of qcomm. But W-CDMA is not just a multiplexing standard. It is a complete specification set that defines in detail how mobile phones communicate with base stations, how signals are modulated, and how data frames are constructed.

术语 CDMA 在移动通讯领域通常特指 Qualcomm 开发的 CDMA 标准族。它们定义了一组移动通讯协议。

The term CDMA in the field of mobile communication usually refers to the CDMA standard family developed by Qualcomm. They define a set of mobile communication protocols.

CDMA 作为复用技术,既用于 W-CDMA 空中接口协议,也用于 Qualcomm 的 CDMA 协议。

As a multiplexing technology, CDMA is used not only for W-CDMA air interface protocol, but also for CDMA protocol of Qualcomm.

W-CDMA 专指在 IMT-2000 中定义的移动电话协议。

W-CDMA refers to the mobile phone protocol defined in IMT-2000.

W-CDMA 协议与 Qualcomm 开发的 CDMA 无关。

W-CDMA protocol has nothing to do with CDMA developed by Qualcomm.

CDMA 标准族(cdmaOne 和 CDMA2000)不兼容 W-CDMA 标准族。

CDMA standard families (cdmaOne and CDMA2000) are not compatible with W-CDMA standard families.

技术

technology

W-CDMA 可以使用非成对或者成对频段,虽然所有当前 W-CDMA 设备(例如 FOMAandUMTS)使用两个 5MHz 频段,一个用于上行一个用于下行。

W-CDMA can use unpaired or paired bands, although all current W-CDMA devices (such as Foma and UMTS) use two 5MHz bands, one for uplink and one for downlink.

发展情况

Development

移动通信市场和 WCDMA

Mobile communication market and WCDMA

首先,全球移动通信发展的速度非常迅速,1999 年已经超过 4 亿用户,其中一半以上是 GSM 用户,其他主要是 PDC 和 IS-95 的用户。按照最新的估计,全球达到 10 亿用户的里程碑将会在 2002 年上半年。全球上网手机的数量超过上网 PC 的数量的时间将提前到 2002 年。在 2000 年能上网的手机市场已达到 6000 万。其中,支持 WAP(无线应用协议)的手机占到约 4000 万。中国的移动通信用户也已经突破九千万。诺基亚预测上网手机数量将增加到 2 亿左右,其中 WAP 手机有 1.8 亿。

First of all, the development of global mobile communication is very fast. In 1999, there are more than 400 million users, more than half of them are GSM users, and the others are mainly PDC and IS-95 users. According to the latest estimates, the global milestone of 1 billion users will be in the first half of 2002. The time when the number of Internet mobile phones exceeds the number of Internet PCs will be advanced to 2002. In 2000, the mobile phone market with internet access reached 60 million. Among them, about 40 million mobile phones support WAP (Wireless Application Protocol). China has more than 90 million mobile communication users. Nokia predicts that the number of Internet connected mobile phones will increase to about 200 million, including 180 million WAP phones.

移动运营主要面临的就是 Internet 业务和其他增值业务,如银行业务、定位业务等的引入。这方面日本的 NTTDoCoMo 率先引入了 I-Mode 移动 Internet 业务,取得了巨大的商用成功,目前有一万多个商业网站在经营 I-Mode 业务。新业务的引入对无线通信网络提出了新的要求。GPRS 一类在建立在原有制式上的数据传输方案已经远远不能满足需求,需要一类适合于宽带数据业务和 IP 业务的新的宽带移动通信系统。

Mobile operation is mainly faced with the introduction of Internet services and other value-added services, such as banking services, positioning services and so on. In this regard, NTTDoCoMo of Japan took the lead in introducing I-mode mobile Internet service, and achieved great commercial success. At present, more than 10000 commercial websites are operating I-mode business. The introduction of new services puts forward new requirements for wireless communication networks. GPRS, a kind of data transmission scheme based on the original system, has been far from meeting the demand. A new broadband mobile communication system suitable for broadband data service and IP service is needed.

其次,原有业务由于使用的频谱比较少(不到 100MHz),加上第二代技术的频谱效率本身比较低,甚至无法满足现有的以语音为主的业务需求。实际上在一些国家和城市的中心地带容量严重不足,日本等国家和一些中心城市的问题尤为突出。

Secondly, the original services use less spectrum (less than 100MHz) and the spectrum efficiency of the second generation technology is relatively low, so it can not even meet the needs of existing voice based services. In fact, the lack of capacity of some cities and cities in Japan is particularly serious.

ITU 早在 WRC92 会议上就为 IMT-2000 规划了 120MHz(1920MHz-1980MHz,2110MHz-2170MHz)的对称频谱资源供 FDD 使用,35MHz(1900MHz-1920MHz,2010MHz-2025MHz)的非对称频谱资源供 TDD 使用。WRC2000 的会议上又增加了 800MHz 频段(806-960MHz),1.7GHz 频段(1710-1885MHz),2.5GHz 频段(2500-2690MHz)供 IMT-2000 业务使用,两者相加使得 3G 未来的频谱有 500MHz 以上,为未来的应用预留了巨大的资源空间。

ITU has planned 120 MHz (1920mhz-1980mhz, 2110mhz-2170mhz) symmetric spectrum resources for IMT-2000 at wrc92 conference, and 35MHz (1900mhz-1920mhz, 2010mhz-2025mhz) asymmetric spectrum resources for TDD. The wrc2000 conference added 800MHz (806-960mhz), 1.7GHz (1710-1885mhz), and 2.5GHz (2500-2690mhz) for IMT-2000 services. The sum of the two makes 3G spectrum more than 500MHz in the future, which reserves huge resource space for future applications.

再者,全球一体化的进程迫切需要一个全球统一的移动通信系统,第二代移动通信系统现有的多制式的空中接口和网络设备,不可能实现这个要求,因此新的有望实现全球统一的移动通信系统 WCDMA-FDD 被寄予厚望。

Moreover, the process of global integration urgently needs a globally unified mobile communication system. The existing multi standard air interface and network equipment of the second generation mobile communication system can not achieve this requirement. Therefore, the new mobile communication system WCDMA-FDD, which is expected to achieve global unification, is expected.

最后,移动通信技术日新月异,第二代通信系统的标准化和产业化工作已经完成了很久,其主要目的当时也仅仅是为了解决语音通信的需求。随着 CDMA 等无线通信技术的日益成熟,以及无线数据通信技术的发展,需要对原来无线通信技术体制进行相应的更新,提高频谱资源的利用效率,提高运营商的成本收益。

Finally, with the rapid development of mobile communication technology, the standardization and industrialization of the second generation communication system has been completed for a long time, and its main purpose at that time was only to meet the needs of voice communication. With the increasing maturity of CDMA and other wireless communication technologies, as well as the development of wireless data communication technology, it is necessary to update the original wireless communication technology system to improve the utilization efficiency of spectrum resources and the cost-benefit of operators.

3G 的标准化需求是市场和技术双重驱动的行为,3G 的标准制定和系统开发工作已经基本完成。3G 的商用进程也在进行中,最早是韩国 cdma2000-1x 于 2000 年底开始商用,日本预计 2001 年 7 月份左右开始商用 WCDMA-FDD,中国和欧洲计划商用 WCDMA 的时间计划在 2002 年左右。

The standardization demand of 3G is driven by both market and technology. The standard formulation and system development of 3G have been basically completed. The commercial process of 3G is also in progress. The earliest commercial application of 3G is cdma2000-1x in South Korea at the end of 2000. Japan is expected to start commercial WCDMA-FDD around July 2001. China and Europe plan to start commercial WCDMA around 2002.

2001 年,日本 NTT DoCoMo 公司的 FOMA 是世界上第一个商业运营 W-CDMA 服务。J-Phone 日本电话(现软件银行)已经继推出基于 W-CDMA 服务后,声称“沃达丰全球标准”兼容 UMTS(尽管 2004 年时还有争议)。2003 年初,和记黄埔逐步在全球运营他们的 UMTS 网络(简称 3)。

In 2001, Foma of NTT DoCoMo was the first commercial W-CDMA service in the world. J-PHONE Japan phone (now software bank) has claimed that “Vodafone global standard” is compatible with UMTS after launching W-CDMA based service (although there was controversy in 2004). In early 2003, Hutchison Whampoa gradually operated its UMTS Network (3) around the world.

大多数欧洲 GSM 运营商计划未来某个时间推出 UMTS 服务,尽管有几个已经把此服务提到日程上来,有一些甚至从 2003 年底就开始运营 UMTS 网络。沃达丰于 2004 年 2 月在欧洲多个 UMTS 网络投入运行。沃达丰还打算在其他国家(包括澳大利亚及新西兰)建设 UMTS 网络。AT&T 无线(现被 Cingular 收购,并沿用 AT&T 品牌)在一些城市开通了 UMTS。尽管因为公司兼并使得网络建设进度被延迟,但 Cingular 已宣布计划在 2005 年与 HSDPA 一起部署 W-CDMA。

Most European GSM operators plan to launch UMTS services some time in the future, although several have already put this service on the agenda, and some have even started operating UMTS networks since the end of 2003. Vodafone launched several UMTS networks in Europe in February 2004. Vodafone also plans to build UMTS networks in other countries, including Australia and New Zealand. At & T wireless (now acquired by Cingular and using the at & T brand) has launched UMTS in some cities. Cingular has announced plans to deploy W-CDMA with HSDPA in 2005, despite delays in network construction due to the merger.

TeliaSoner

TeliaSoner


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