毕业论文外文翻译通用移动通信系统的回顾

1、外文资料与中文翻译外文资料：Review of UMTSUMTS Network ArchitectureThe European/Japanese 3G standard is referred to as UMTS. UMTS is one of a number of standards ratified by the ITU-T under the umbrella of IMT-2000. It is currently the dominant standard, with the US CDMA2000 standard gaining ground, particularly

2、with operators that have deployed cdmaOne as their 2G technology. At time of writing,Japan is the most advanced in terms of 3G network deployment. The three incumbent operators there have implemented three different technologies: J-Phone is using UMTS,KDDI has a CDMA2000 network, and the largest ope

3、rator NTT DoCoMo is using a system branded as FOMA (Freedom of Multimedia Access). FOMA is based on the original UMTS proposal, prior to its harmonization and standardization.The UMTS standard is specified as a migration from the second generation GSM standard to UMTS via the General Packet Radio Sy

4、stem (GPRS) and Enhanced Data for Global Evolution (EDGE), as shown in Figure. This is a sound rationale since as of April 2003, there were over 847 Million GSM subscribers worldwide1, accounting for 68% of the global cellular subscriber figures. The emphasis is on keeping as much of the GSM network

5、 as possible to operate with the new system.We are now well on the road towards Third Generation (3G), where the network will support all traffic types: voice, video and data, and we should see an eventual explosion in the services available on the mobile device. The driving technology for this is t

6、he IP protocol. Many cellular operators are now at a position referred to as 2.5G, with the deployment of GPRS, which introduces an IP backbone into the mobile core network.The diagram below, Figure 2, shows an overview of the key components in a GPRS network, and how it fits into the existing GSM i

7、nfrastructure.The interface between the SGSN and GGSN is known as the Gn interface and uses the GPRS tunneling protocol (GTP, discussed later). The primary reason for the introduction of this infrastructure is to offer connections to external packet networks, such as the Internet or a corporate Intr

8、anet.This brings the IP protocol into the network as a transport between the SGSN and GGSN. This allows data services such as email or web browsing on the mobile device,with users being charged based on volume of data rather than time connected.The dominant standard for delivery of 3G networks and s

9、ervices is the Universal Mobile Telecommunications System, or UMTS. The first deployment of UMTS is the Release 99 architecture, shown below inigFure 3.In this network, the major change is in the radio access network (RAN) with the introduction of CDMA technology for the air interface, and ATM as a

10、transport in the transmission part. These changes have been introduced principally to support the transport of voice, video and data services on the same network. The core network remains relatively unchanged, with primarily software upgrades. However, the IP protocol pushes further into the network

11、 with the RNC now communicating with the 3G SGSN using IP.The next evolution step is the Release 4 architecture, Figure 4. Here, the GSM core is replaced with an IP network infrastructure based around Voice over IP technology.The MSC evolves into two separate components: a Media Gateway (MGW) and an

12、 MSC Server (MSS). This essentially breaks apart the roles of connection and connection control. An MSS can handle multiple MGWs, making the network more scaleable.Since there are now a number of IP clouds in the 3G network, it makes sense to merge these together into one IP or IP/ATM backbone (it i

13、s likely both options will be available to operators.) This extends IP right across the whole network, all the way to the BTS.This is referred to as the All-IP network, or the Release 5 architecture, as shown in Figure 5. The HLR/VLR/EIR are generalised and referred to as the HLR Subsystem(HSS).Now

14、the last remnants of traditional telecommunications switching are removed, leaving a network operating completely on the IP protocol, and generalised for the transport of many service types. Real-time services are supported through the introduction of a new network domain, the IP Multimedia Subsyste

15、m (IMS).Currently the 3GPP are working on Release 6, which purports to cover all aspects not addressed in frozen releases. Some call UMTS Release 6 4G and it includes such issues as interworking of hot spot radio access technologies such as wireless LAN.UMTS FDD and TDDLike any CDMA system, UMTS nee

16、ds a wide frequency band in which to operate to effectively spread signals. The defining characteristic of the system is the chip rate, where a chip is the width of one symbol of the CDMA code. UMTS uses a chip rate of 3.84Mchips/s and this converts to a required spectrum carrier of 5MHz wide. Since

17、 this is wider than the 1.25MHz needed for the existing cdmaOne system, the UMTS air interface is termed wideband CDMA.There are actually two radio technologies under the UMTS umbrella: UMTS FDD and TDD. FDD stands for Frequency Division Duplex, and like GSM, separates traffic in the uplink and down

18、link by placing them at different frequency channels. Therefore an operator must have a pair of frequencies allocated to allow them to run a network, hence the term pairedspectrum TD. D or Time Division Duplex requires only one frequency channel, and uplink and downlink traffic are separated by send

19、ing them at different times. The ITU-T spectrum usage, as shown in Figure 6, for FDD is 1920980MHz for uplink traffic, and 2110-2170MHz for downlink. The minimum allocation an operator needs is two paired 5MHz channels, one for uplink and one for downlink, at a separation of 190MHz. However, to prov

20、ide comprehensive coverage and services, it is recommended that an operator be given three channels. Considering the spectrum allocation, there are 12 paired channels available, and many countries have now completed the licencing process for this spectrum, allocating between two and four channels pe

21、r licence. This has tended to work out a costly process for operators, since the regulatory authorities in some countries, notably in Europe, have auctioned these licences to the highest bidder. This has resulted in spectrum fees as high as tens of billions of dollars in some countries.The Time Divi

22、sion Duplex (TDD) system, which needs only one 5MHz band in which to operate, often referred to as unpaired spectrum. The differences between UMTS FDD and TDD are only evident at the lower layers, particularly on the radio interface. At higher layers, the bulk of the operation of the two systems is

23、the same. As the name suggests, the TDD system separates uplink and downlink traffic by placing them in different time slots. As will be seen later, UMTS uses a 10ms frame structure which is divided into 15 equal timeslots. TDD can allocate these to be either uplink or downlink,with one or more brea

24、kpoints between the two in a frame defined. In this way, it is well suited to packet traffic, since this allows great flexibility in dynamically dimensioning for asymmetry in traffic flow.The TDD system should not really be considered as an independent network, but rather as a supplement for an FDD

25、system to provide hotspot coverage at higher data rates. It is rather unsuitable for large scale deployment due to interference between sites, since a BTS may be trying to detect a weak signal from a UE, which is blocked out by a relatively strong signal at the same frequency from a nearby BTS. TDD

26、is ideal for indoor coverage over small areas.Since FDD is the main access technology being developed currently, the explanations presented here will focus purely on this system.UMTS Bearer ModelThe procedures of a mobile device connecting to a UMTS network can be split into two areas: the access st

27、ratum (AS) and the non-access stratum (NAS). The access stratum involves all the layers and subsystems that offer general services to the non-access stratum. In UMTS, the access stratum consists of all of the elements in the radio access network, including the underlying ATM transport network, and t

28、he various mechanisms such as those to provide reliable information exchange. All of the non-access stratum functions are those between the mobile device and the core network, for example, mobility management. Figure 7 shows the architecture model. The AS interacts with the NAS through the use of se

29、rvice access points (SAPs).UMTS radio access network (UTRAN) provides this separation of NAS and AS functions, and allows for AS functions to be fully controlled and implemented within the UTRAN. The two major UTRAN interfaces are the Uu, which is the interface between the mobile device, or User Equ

30、ipment (UE) and the UTRAN, and the Iu, which is the interface between the UTRAN and the core network. Both of these interfaces can be divided into control and user planes each with appropriate protocol functions.A Bearer Service is a link between two points, which is defined by a certain set of char

31、acteristics. In the case of UMTS, the bearer service is delivered using radio access bearers.A Radio Link is defined as a logical association between a single User Equipment (UE) and a single UTRAN access point, such as an RNC. It is physically comprised of one or more radio bearers and should not b

32、e confused with radio access bearer.Looking within the UTRAN, the general architecture model is as shown in Figure 8 below. Now shown are the Node B or Base Station (BTS) and Radio Network Controller (RNC) components, and their respective internal interfaces. The UTRAN is subdivided into blocks refe

33、rred to as Radio Network Subsystems (RNS), where each RNS consists of one controlling RNC (CRNC) and all the BTSs under its control. Unique to UMTS is the interface between RNSs, the Iur interface, which plays a key role in handover procedures. The interface between the BTS and RNC is the Iub interf

34、ace.All the I interfacIeusr:aIun,d Iub, currently3 use ATM as a transport layer. In thecontext of ATM, the BTS is seen as a host accessing an ATM network, within which the RNC is an ATM switch. Therefore, the Iub is a UNI interface, whereas the Iu and Iur interfaces are considered to be NNI, as illu

35、strated in Figure 9.This distinction is because the BTS to RNC link is a point-to-point connection in that a BTS or RNC will only communicate with the RNC or BTS directly connected to it, and will not require communication beyond that element to another network element.For each user connection to th

36、e core network, there is only one RNC, which maintains the link between the UE and core network domain, as highlighted in Figure 10. This RNC is referred to as the serving RNC or SRNC. That SRNC plus the BTSs under its control is then referred to as the SRNS. This is a logical definition with refere

37、nce to that UE only. In an RNS, the RNC that controls a BTS is known as the controlling RNC or CRNC. This is with reference to the BTS, cells under its control and all the common and shared channels within.As the UE moves, it may perform a soft or hard handover to another cell. In the case of a soft

38、 handover, the SRNC will activate the new connection to the new BTS. Should the new BTS be under the control of another RNC, the SRNC will also alert this new RNC to activate a connection along the Iur interface. The UE now has two links, one directly to the SRNC, and the second, through the new RNC

39、 along the Iur interface. In this case, this new RNC is logically referred to as a drift RNC or DRNC, see Figure 10. It is not involved in any processing of the call and merely relays it to the SRNC for connection to the core. In summary, SRNC and DRNC are usually associated with the UE and the CRNC

40、 is associated with the BTS. Since these are logical functions it is normal practice that a single RNC is capable of dealing with all these functions.A situation may arise where a UE is connected to a BTS for which the SRNC is not the CRNC for that BTS. In that situation, the network may invoke the

41、Serving RNC Relocation procedure to move the core network connection. This process is described inSection 3.中文翻译：通用移动通信系统的回顾UMTS 网络架构欧洲/日本的 3G 标准，被称为 UMTS。 UMTS 是一个在 IMT-2000 保护伞下的 ITU-T 批准的许多标准之一。 随着美国的 CDMA2000 标准的 发展，它是目前占主导地位的标准，特别是运营商将cdma One部署为他们的 2G 技术。在写这本书时，日本是在 3G 网络部署方面最先进的。三 名现任运营商已经实施了

42、三个不同的技术：J - PHONE使用UMTS ,KDDI 拥有 CDMA2000 网络，最大的运营商 NTT DoCoMo 正在使用品牌的 FOMA （自由多媒体接入）系统。 FOMA 是基于原来的 UMTS 协议， 而且更加的协调和标准化。UMTS标准被定义为一个通过通用分组无线系统（ GPRS）和全球 演进的增强数据技术（EDGE）从第二代GSM标准到UNTS的迁移，如 图。这是一个广泛应用的基本原理，因为自 2003年 4月起，全球有超过 847万GSM用户，占全球的移动用户数字的68%。重点是在保持尽可能 多的 GSM 网络与新系统的操作。我们现在在第三代（3G）的发展道路上，其中网

43、络将支持所有类型 的流量：语音，视频和数据，我们应该看到一个最终的爆炸在移动设备 上的可用服务。此驱动技术是 IP 协议。现在，许多移动运营商在简称为 2.5G的位置，伴随GPRS的部署，即将IP骨干网引入到移动核心网。在 下图中，图2显示了一个在GPRS网络中的关键部件的概述，以及它是 如何适应现有的 GSM 基础设施。SGSN和GGSN之间的接口被称为Gn接口和使用GPRS隧道协议 （GTP 的，稍后讨论）。引进这种基础设施的首要原因是提供连接到外部 分组网络如，In ternet或企业Intranet。这使IP协议作为SGSN和GGSN 之间的运输工具应用到网络。这使得数据服务，如移动设

44、备上的电子邮 件或浏览网页，用户被起诉基于数据流量，而不是时间连接基础上的数 据量。 3G 网络和服务交付的主要标准是通用移动通信系统，或 UMTS。 首次部署的 UMTS 是发行 99 架构，在下面的图 3 所示。在这个网络中，主要的变化是在无线接入网络（ RAN 的） CDMA 空中接口技术的引进，和在传输部分异步传输模式作为一种传输方式。 这些变化已经引入，主要是为了支持在同一网络上的语音，视频和数据 服务的运输。核心网络保持相对不变，主要是软件升级。然而，随着目 前无线网络控制器使用IP与3G的GPRS业务支持节点进行通信，IP协 议进一步应用到网络。未来的进化步骤是第 4 版架构，如

45、图 4。在这里， GSM 的核心被以 语音 IP 技术为基础的 IP 网络基础设施取代。海安的发展分为两个独立部分：媒体网关（ MGW ）和 MSC 服务器 （MSS）的。这基本上是打破外连接的作用和连接控制。一个 MSS可以 处理多个 MGW ，使网络更具有扩展性。因为现在有一些在 3G 网络的 IP 云，合并这些到一个 IP 或 IP/ ATM 骨干网是很有意义的（它很可能会提供两种选择运营商） 。这使 IP 权利 拓展到整个网络，一直到BTS（基站收发信台）。这被称为全IP网络，或 推出五架构，如图五所示。在 HLR/ VLR/VLR/EIR 被推广和称为 HLR 的子系统（ HSS）。

46、现在传统的电信交换的最后残余被删除， 留下完全基于 IP 协议的网 络运营，并推广了许多服务类型的运输。实时服务通过引入一个新的网 络域名得到支持，即 IP 多媒体子系统（ IMS）。目前3GPP作用于第6版，意在包含冷冻版本没有涵盖所有方面。 有些人称 UMTS 第 6 版为 4G 和它包括热点无线电接入技术，如无线局 域网互联互通的问题。UMTS 的 FDD 和 TDD像任何 CDMA 系统， UMTS 需要一个宽的频带，在这个频带上有 效地传播信号。该系统的特点是芯片的速度，芯片是一个符号的 CDMA 代码的宽度。UMTS使用的芯片速率为3.84Mchips/秒，这转换到所需 的频谱载波

47、宽度为 5MHz 。由于这比现有的 cdmaOne 系统所需的 1.25MHz带宽要宽，UNTS空中接口被称为 宽带” CDMA.实际上在 UMTS 下有两个无线电技术： UMTS 软盘驱动器和时分双 工。FDD代表频分双工，如GSM，通过把它们放置在不同的频率信道分 离为交通上行和下行。因此，一个运营商必须有一对频率分配，使他们 能够运行网络， 即术语成对频谱。 TDD 或时分双工只需要一个频率通道， 上行和下行流量是在不同的时间分开发送。 ITU-T 的频谱使用，如在图 6所示。对于FDD是1920 - 1980MHz的为上行流量，2110-2170MHZ为 下行的。运营商需要的最小分配是

48、两个成对 5MHz 的信道，一个用于上 行，一个用于下行的，两者相分离 190MHz。然而，为了给客户提供全 面的覆盖和服务，建议给予每个运营商三个信道。考虑到频谱分配，有 12 对可用的渠道，现在许多国家都完成了这个频谱的许可过程，每个许 可证配置两个到四个信道。这趋向给运营商造成一个昂贵的花费，因为 一些国家的监管部门，特别是在欧洲，已经将这些许可证拍卖给出价最 高的人。这就造成了频谱费用在一些国家高达数十亿美元。时分双工（TDD ）系统，只需要一个5MHz的带宽在其中操作，通 常被称为非成对频谱。 UMTS FDD 和 TDD 之间的差异只有在较低层明 显，特别是在无线接口。在更高的层次

49、，两个系统的运作大部分是相同 的。正如它的名字表明， TDD 系统通过把它们放置在不同的时间空挡分 为上行流量和下行流量。 正如我们以后可以看到的， UMTS 使用一个分 为15个相等的时隙的10ms帧结构。时分双工可以分配这些为上行或下 行，在一个确定的帧结构中这两者间可以有一个或多个断点。以这种方 式，这是非常适合数据包通信的，因为这对于不对称的通信流的动态标 注可以有极大的灵活性。TDD 系统真的不应该被视为一个独立的网络，而是作为一个 FDD 系统的补充， 提供更高的数据传输率的热点覆盖。 由于站点之间的干扰， 它相当不合适用作大规模部署，因为一个基站可以尝试从 UE 检测微弱 信号，

50、这被来自邻近基站的相同频率的相对较强的信号阻止了。 时分双 工对于小面积的室内覆盖是理想的。由于 FDD 是目前正在发展的主要的接入技术， 这里介绍的解释将完 全专注于这个系统。UMTS 承载模型移动设备连接到UMTS网络的程序可以分成两领域：接入层（AS） 和非接入层（NAS ）。接入层涉及所有提供普遍服务的非接入层和子系统 阶层。在 UMTS 接入层包括无线接入的所有元素网络， 包括潜在的 ATM 传输网络，各种机制提供可靠的信息交换等。所有的非接入层功能都在 移动设备和核心网络之间，例如，移动性管理。图 7 显示了结构模型。 AS通过使用服务接入点（SAPS）与NAS交互。UMTS 无线

51、接入网（ UTRAN ）提供 NAS 和 AS 功能的分离，并允 许 AS 功能在 UTRAN 中被完全控制和实施。 两大 UTRAN 的接口是 UU， 这是移动设备之间的接口，或者用户设备（UE）和UTRAN之间，lu， 这是 UTRAN 和核心网之间的接口。这些接口都可以分为控制平面和用 户平面，每个都有适当的协议功能。承载服务是两点间的连接，这是由 一组特定的特点定义的。在 UMTS 的情况下，使用无线接入承载提供承 载服务。无线接入承载（RAB ）被定义为用户设备和核心网络之间的服务， 即接入层（ ieUTRAN ）为非接入层提供用户数据传输。一个 RAB 可以 由一些支流组成，这是数

52、据流在有不同的 QoS 特性的 RAB 流向核心网 络，如不同的可靠性。一个常见的例子是不同类别的位有不同的位错误 率，可以实现不同的 RAB 子流。 RAB 子流在 RAB 建立和释放的同时建 立和释放，并通过相同的传输承载一起传输。无线电链路被定义为一个单一的用户设备（UE ）和一个单一的UTRAN接入点之间的逻辑关联，如一个 RNC。它实际上是由一个或多 个无线承载组成和不应和无线接入承载混淆。在 UTRAN 内部来看，总体架构模型在下面的图 8 所示。现在 显示的是节点B基站（BTS）和无线网络控制器（RNC）组件，以及它 们各自的内部接口。UTRAN分为被称为无线网络子系统（RNS）

53、的块， 其中每个 RNS 由一个控制 RNC 和控制下的所有基站组成。 UMTS 的独 特之处是 RNS 之间的接口， Iur 接口，在交接过程起了关键作用。基站 和 RNC 之间的接口是 Iub 接口。所有“I接口： lu，Iur和Iub, currently3将ATM用作传输层。在ATM 的背景下， BTS 被看作是 ATM 网络的主机访问，在这个网络中 RNC 是 一个 ATM 交换机。因此， Iub 是一个 UNI 接口，而 Iu 和 Iur 接口被认为 是 NNI ，如图 9 所示。这种区别是因为基站到 RNC 的链接是一个点至点连接，在这个连 接中一个基站或 RNC 只和与它直接连

54、接的 RNC 或基站通信，并且不会 要求和其他网络元素的元素。对于每个用户连接到核心网络，这里只有一个 RNC，保持UE和核 心网域之间的联系， 在图 10 中突出显示。 RNC 是指服务 RNC 或 SRNC。 SRNC加上在其控制下的基站被称为 SRNS。这是一个只以UE为参考的 逻辑定义。在一个 RNS 中，控制基站的 RNC 被称为控制 RNC 或 CRNC。 这是以基站为参考，其控制下的部分和所有常见的和共享的渠道内。因为UE移动，它可能执行软或硬切换到另一个蜂窝。在软切换的 情况下，SRNC将启动新的连接到新的基站。新的基站应该是在另一个 RNC控制下，SRNC中也会提醒这个新的R

55、NC启动沿Iur接口连接。UE 现在有两个连接，一个直接连接 SRNC，第二个通过新的RNC连接Iur 接口。在这种情况下，这个新的RNC在逻辑上被称为漂移RNC或DRNC， 见图10。它不涉及任何呼叫处理，只是将它中继到 SRNC以连接核心网 络，总之，SRNC和DRNC通常与UE相关联，CRNC与BTS相关联。 由于这些是逻辑功能，一个单一的RNC是能够处理所有这些功能是很正 常的做法。一个UE连接到基站，它的SRNC并不是这个基站的控制 RNC，这 种情况可能会出现。在这种情况下，这个网络可以调用 SRNC的搬移程 序来移动核心网络的连接。五分钟搞定5000字毕业论文外文翻译， 你想要的工具都在 这里！在科研过程中阅读翻译外文文献是一个非常重要的环节， 许多领域高水平的文献都是外文文献，借鉴一些外文文献翻译 的经验是非常必要的。由于特殊原因我翻译外文文献的机会比 较多，慢慢地就发现了外文文献翻译过程中的三大利器： Google翻译”频道、金山词霸（完整版本）和 CNKI “翻译助手。具体操作过程如下：1先打开金山词霸自动取词功能，然后阅读文献；2遇到无法理解的长句时，可