专业英语文献翻译 通信工程

英语原文: Third generation mobile communication system QoS and resource management [Abstract] With the constant improvement of communication network, the user provides the network requirements and continuously improve business performance, QoS (Quality of Service) communication systems has become a very important indicator to determine the user's satisfaction. This article outlines the third generation mobile communication systems (3G) of QoS resource management, which focused on describing the global system for mobile communications (UMTS), QoS. 1. Introduction Currently, the global mobile communications is developing at an unprecedented speed, while the 3G standards are continuously improved. 3G mobile environment, end users will provide voice, data and multimedia services. In the ITU-T E.800 recommendation, QoS is defined as the business performance of the combined effect, determines the user's satisfaction. QoS is applied to all the performance factors of the business combination that these performance factors such as the business can maintain, easy access to nature, can be super, integrity and security. 2. UMTS QoS 2.1 UMTS QoS structure Circuit core network domain MSC/ VLR HLRe/AC SSP Wireless part MS 1X BSC 1X BTS MSCe/ VLR SSP PCF 1X BTS MGW 1X BSC 1X BTS PCF Packet domain core network HRPD BSC HRPD BTS PDSN/FA HA/CCG AT PCF AAA AN AAA US NS In order to achieve the network QoS, the business must be established between the start and end points clearly defined properties and functions of the bearer service. Network bearer service describes how to provide QoS in the network, while carrying business from the signaling protocol, the user plane transport and QoS management capabilities to define. When the end of the business involves more than one network, the bearer service by the end of the business through the path composed of different network bearer services. In UMTS, the business can be broken down into end-terminal equipment / mobile terminal (TE / MT) local bearer service, the external bearer services and UMTS bearer service. TE / MT local bearer service for mobile station (MS), the communication between the different components, these components can be connected to one or more MT and the TE, which is responsible for the air interface to MT UMTS Terrestrial Radio Access Network (UTRAN ) the physical connection. External bearer service is responsible for the core network (CN) and the external network connection to the terminal. UMTS bearer service by the radio access bearer (RAB) service and core network bearer service to achieve these two operations reflects the network topology in their cellular UMTS bearer service to achieve best practice. RAB business in the MT and CN Iu Edge Node to provide signaling and user data between the confidentiality of transmission, such transmission will ensure that UMTS bearer service QoS negotiation or signaling the default QoS. The service is based wireless interface features, and also for a moving MT to maintain its QoS. CN bearer service connection UMTS CN Iu Edge Node and the CN gateway to the outside network, the role of the business for the effective control and use the backbone network to provide consultation UMTS bearer service. UMTS packet core network will support different QoS requirements of various backbone bearer service. RAB bearer services and wireless business by the Iu bearer service to achieve. Wireless bearer service covering all aspects of the wireless interface transfer, the business use of UTRA frequency division duplex or time division duplex (UTRA FDD / TDD) services. Iu bearer service provides transport between UTRAN and CN, the packet service, Iu bearer service has different QoS requirements will provide the bearer service. CN bearer service to use a common backbone network services. Backbone services, including the first and second floors of the network function, according to the needs of operators to choose. UMTS backbone network service is not defined, can take advantage of existing standards. 2.2 UMTS QoS requirements The general requirements for UMTS QoS can be summarized as follows: (1) QoS parameters should not be one or a few external QoS control mechanisms of the restrictions, but should be through the use of UMTS QoS control mechanisms required to provide different levels of QoS; (2) All the QoS parameters must have a clear meaning; (3) QoS mechanism must allow the efficient use of radio capacity; (4) core network and access network to allow independent evolution; (5) allows the evolution of UMTS network; (6) The combination of all the QoS parameters must have a clear meaning. (7) UMTS QoS control mechanisms should be in MS and the 3G gateway node provided on the basis of other QoS parameters control; (8) UMTS QoS mechanism should be in the application requirements and provide a mapping between UMTS services; (9) UMTS QoS control mechanisms should be able to valid existing QoS interaction between the programs work; (10) QoS should be defined by the UMTS control mechanism to provide different levels of QoS; (11) in the 3G service node, the mode of communication for all groups need to use session-based approach, UMTS QoS must be closely linked, essential features for each address multiple QoS flows; (12) UMTS should provide a limited definition of the QoS; (13) QoS and additional costs caused by program complexity should be as low as possible, the network status information transmission and storage should be as little as possible; (14) QoS should support the effective use of frequencies; (15) QoS parameters need to support asymmetric bearer service; (16) applications or MS and 3G gateway node in a special data transfer software should be specified in its QoS values; (17) QoS role should be dynamic; (18) QoS should be as the number of parameters less. 2.3 UMTS QoS Classification and Properties The above mentioned hierarchy needs to define each bearer service QoS attributes (parameter group), these attributes are used to map the QoS requirements of end to end of each bearer service requirements. That the classification of business-level QoS for real-time based on business requirements for the classification of the business, there are four, in accordance with strict real-time requirements to a wide array of session-level, interactive level, flow level and background level, their basic characteristics and typical applications shown in Table 2. Table 1 shows, there are different business-level requirements of different QoS attributes. 2.4UMTS QoS management capabilities All entities of the UMTS QoS management functions will ensure that UMTS bearer service access points of the negotiations between the business, while, by and between UMTS external business translation and mapping to provide end to end business. (1) UMTS bearer service control plane QoS management functions, the business equivalent to the control plane to establish, change and maintain the capabilities to provide all user plane QoS management functions of the related properties. Business Management can also provide services in other circumstances, he can translate to lower property issued by the business request, you can also ask other control functions to provide the business entity to receive permission to signal. Translation, the UMTS bearer service control of internal and external network service primitives service control interface for various protocols required for conversion. UMTS bearer service attributes, including external networks service control protocol and the QoS parameters of the conversion. Access / ability to control, save all available resources on the network entities and allocated to the UMTS bearer service resource information. Appointment control, inspection UMTS bearer service users with specific QoS attributes of the service request administrative privileges. (2) UMTS bearer service user plane QoS management functions of QoS management user plane signaling and user data will be maintained at a certain volume of business within the limits of the QoS attributes with specific values to define. Mapping function for each data unit to provide a particular tag that transmitted the data hosting business unit to receive the desired QoS. Classification, if the MT has multiple UMTS bearer services established, in accordance with the relevant QoS attributes assigned to the MT data unit already established business. Resource management of available resources in the resource sharing among all business allocated according to the QoS required. Traffic regulator, the business unit negotiated QoS and traffic data is consistent. 3. 3G air interface QoS In order to meet the growing demand for anytime, anywhere access to the Internet, Internet business must be seamlessly extended to the MTs, which requires the introduction of the 3G air interface QoS mechanisms to optimize the support of Internet services. Meanwhile, 3G wireless networks and existing businesses need to be there to provide good support for the business. Therefore, 3G air interface QoS mechanism must have some flexibility in order to facilitate introduction of new services, but also in between service providers and end users to provide an effective consultative approach. 3.1 CDMA air interface QoS In the 3G standard, the majority of the air interface with a sophisticated CDMA technology, CDMA air interface QoS of existing programs to meet specific application needs only. Typically, they only provide hard real-time application QoS protection, while the non-real-time applications is the use of best efforts (best effort) delivery mechanism. In order to optimize the network of Internet services and support new business in the network have a flexible QoS mechanisms to protect the literature [3] proposed a 3G CDMA air interface QoS program, based on business classification. We can provide a business system is divided into three levels: premium, gold and silver, each level provides a feature of his performance, that is, group behavior (Group Behavior). Premium business can provide consultations at any time the bandwidth, without regard to the air interface channel characteristics (obstruction, interference and fading, etc.). The other two are with a business-level elasticity, when the air interface is congested, they will be brought according to the elasticity to adjust the bandwidth allocated for the user, so that you can reduce congestion. A level of group behavior is controlled by the power control and spreading to achieve, to achieve a variety of ways, such as by signal to interference ratio based on the target (SIR), adaptive power control and adaptive control to achieve the spreading factor. This program can be used for both uplink of CDMA systems can also be used for the downlink, through the use of class-based bandwidth scheduling scheme to achieve the CDMA air interface of different QoS. Using this QoS scheme, 3G operators can define their own set of business class, choose the most appropriate ways to achieve group behavior, and can be used by business-level accounting program. Because each has a specific performance (latency and throughput), it is easy to achieve air interface of business consultations. Note that, in order to facilitate the control and bandwidth scheduling scheme to achieve the above, you must have a CDMA air interface can show the ability of the radio resource allocation scheme. The radio resource allocation scheme not only used in the conventional transmission / receiver should be able to use, such as those used in multi-user receiver and smart antennas and other performance-enhancing technologies to send receiver. 3.2 TDMA air interface QoS In the 3G wireless network, also based on TDMA air interface, such as EGPRS (Enhanced General Packet Radio Service). EGPRS is an evolution of GSM and TDMA, using a TDMA-based packet-switched wireless technology and an evolution of packet-switched GPRS core network. The current protocol uses EGPRS GPRS core network, and introduces a new air interface, EDGE (Enhanced Data for Global Evolution). 3G wireless networks in order to support different business needs in the TDMA air interface, the introduction of QoS mechanisms. Literature [4] on the 3G EGPRS support in different business-level discussion of different scheduling mechanism, the two types of weighted round robin scheduling method for the study: Radio Access Network (RAN) in the wireless sensing (radio-aware) packet scheduling method and CN edge of the conventional packet scheduling method. The results showed that, for the EGPRS system, when used together if the scheduling status of the wireless link and radio resource management can improve the overall system delay performance. However, use of different business levels weighted round-robin scheduling method does not apply to an interference-limited environment. While multi-slot allocation can also be used to provide different services. 4. 3G RAN's QoS UMTS/IMT-2000 The basic concept is to access the features and functions separately from the core network, RAN for all MTs provides a platform for access to CN. On the CN, the wireless access technology that relies on the functionality and mobility features are not visible. 3GPP access network currently defined there is a difference based on WCDMA and EDGE radio access technology, UTRAN and GSM / EDGE Radio Access Network (GERAN). In the 3G RAN, there must be connected, such as base stations and radio network controller and other network elements of transmission technology. Comprehensive application of its own different requirements for QoS and advanced wireless control requirements imposed on the application, technology transfer must be to provide different services at different levels of QoS. Transport bearer must support multiple QoS requirements and service features. 4.1 ATM-based transmission scheme In the current technology in a variety of packet networks, ATM QoS support is a relatively mature program. The first release in the UMTS version, UTRAN selected ATM/AAL2 (ATM adaptation layer 2) as his transmission technology. UTRAN transport layer in order to meet the stringent requirements for QoS, the need for business management, resource management, etc. be given special attention. Literature [5] lists several ATM/AAL2 the UTRAN transmission performance and design method to study the strict transmission delay requirements of ATM/AAL2 required bandwidth. Conclusion of ATM/AAL2 technology to meet stringent WCDMA UTRAN QoS requirements. 4.2 IP-based transmission scheme 3G RAN network elements not only can ATM/AAL2 technology to interconnect, but also to interconnect via IP technology. IP in the RAN transport solution was chosen mainly because of the following considerations: First, IP QoS management mechanism has been close to maturity; Secondly, IP as a network layer protocol, is independent of the link layer / physical layer design, so and a variety of low-level protocols can work together; again, IP networks have become the benchmark for various business groups; the most critical is the 3G CN is the IP-based. The current IP networks are not sensitive to latency for data applications, therefore, must be improved, for providing IP-based transmission scheme, including delay, jitter and loss, etc. QoS support. IETF in this area a lot of work: real-time transport protocol packet stream RTP, IP network, real-time signaling transport SigTran, integrated services with QoS protection structure IntServ, Integration Services / Resource Reservation Protocol RSVP, service differentiation architecture DiffServ, reduce the overhead of IP header compression IPHC and so on. Mobile Wireless Internet Forum and 3GPP (MWIF) are conducting research in this area, 3GPP findings in the literature [6] can be obtained, MWIF research results in the literature can be obtained [7]. 5. Conclusion Currently, two organizations dedicated to 3G standardization in 3GPP and 3GPP2 are still some of the key 3G technologies in the research and make some of them become the standard. Although 3G has not yet spread out in the world, widely spread is the transition from 2G to 3G networks such as GPRS and CDMA 1x and so on. But as time goes on, business needs, 3G will spread widely in the world. Because 3G support a variety of business, and the user's requirements have become more sophisticated, so must provide QoS for business protection. The ultimate goal is a 3G all-IP network, which also determines the 3G QoS is an integral part. Therefore, the QoS of 3G will be a focus of research in 3G, but 3G's final build will also give priority to guarantee the QoS. References [1] 3GPP TS 23.107 V3.6.0. QoS Concept and Architecture. 2001.4. [2] 3GPP TS 22.105 V3.9.0. Services and Service Capabilities. 2000.6. [3] JY.Guo and H.Chaskar. A Framework for Quality of Service Differentiation on 3G CDMA Air Interface. IEEE WCNC 2000,Chicago,Sept.2000 [4] J.-J.Cai et al. Providing Differentiated Services in EGPRS through PacketSheduling. GLOBECOM 2000,San Franciso,NOV.2000 [5] JS.Nananukul et al.Some Issues in Performance and Design of the ATM/ALL2Transport in the UTRAN. IEEE WCNC 2000,Chicago,Sept.2000 [6] 3GPP TR 25.933. IP Transport in UTRAN Work Task Technical Report. R-00 [7] JMWIF, TR. IP in the RAN as a Transport Option in 3G Mobile System. MTR-006 中文翻译: 第三代移动通信系统的QoS 和资源管理 【摘要】随着通信网络的不断完善，用户对网络所提供的业务性能的要求不断提高，QoS(服务质量)已经成为通信系统的一个非常重要的指标，决定了用户的满意程度。本文概述了第三代移动通信系统(3G)的QoS资源管理，其中着重描述了全球移动通信系统(UMTS)的QoS。 1. 引言 目前，全球移动通信正以前所未有的高速度发展，而3G的 标准 excel标准偏差excel标准偏差函数exl标准差函数国标检验抽样标准表免费下载红头文件格式标准下载 也在不断完善。3G将为移动环境下的终端用户提供话音、数据以及各种多媒体业务。在ITU-T E.800 建议中，QoS 被定义为业务性能的综合效果，决定了用户的满意程度。QoS 由应用于业务的所有性能因素的组合 表 关于同志近三年现实表现材料材料类招标技术评分表图表与交易pdf视力表打印pdf用图表说话 pdf 示，这些性能因素如业务的可保持性、易获得性、可超作性、完整性以及安全性等。 2. UMTS QoS 2.1 UMTS QoS 的结构 UMTS QoS 结构如图所示。 核心网电路域 MSC/ VLR HLRe/AC SSP 无线部分 MS 1X BSC 1X BTS MSCe/ VLR SSP PCF 1X BSC 1X BTS MGW 1X BTS PCF 核心网分组域 HRPD BSC HRPD BTS PDSN/FA HA/CCG AT PCF AAA AN AAA 用户侧 网络侧 UMTS QoS 结构如图 为了实现网络的QoS，必须在业务的起点和终点之间建立明确定义了的属性和功能的承载业务。网络的承载业务描述了该网络是如何提供QoS 的，而承载业务由信令协议、用户平面传输和QoS 管理功能来定义。当端到端的业务涉及到多个网络时，端到端的承载业务由业务所经路径上不同网络的承载业务组成。 在UMTS 中，端到端的业务可以分解成终端设备/移动终端(TE/MT)局部承载业务、外部承载业务和UMTS 承载业务。TE/MT 局部承载业务负责移动台(MS)的不同组成部分之间的通信，这些组成部分可以是MT 和一个或几个相连的TE,其中MT 负责通过空中接口到UMTS 陆地无线接入网(UTRAN)的物理连接。外部承载业务则负责核心网络(CN)和外部网络终端的连接。UMTS 承载业务由无线接入承载(RAB)业务和核心网承载业务来实现，这两种业务反映了在各自蜂窝网络拓扑上实现UMTS 承载业务的最优方法。 RAB 业务在MT 和CN Iu 边缘节点之间提供信令和用户数据的保密传输，这种传输将保证UMTS 承载业务协商的QoS 或信令的缺省QoS。该业务基于无线接口的特性，并且对正在移动的MT 也保持其QoS。 CN 承载业务连接UMTS CN Iu 边缘节点和通向外部网络的CN 网关，该业务的作用为有效地控制和利用骨干网来提供协商的UMTS 承载业务。UMTS 分组核心网将支持有不同QoS 要求的各种骨干网承载业务。 RAB 业务由无线承载业务和Iu 承载业务来实现。无线承载业务覆盖无线接口传输的所有方面，该业务利用UTRA 频分双工或时分双工(UTRA FDD/TDD)业务。Iu 承载业务提供UTRAN 和CN 之间的传输，对分组业务，Iu 承载业务将提供有不同QoS 要求的承载业务。 CN 承载业务利用通用的骨干网业务。骨干网业务包括网络第一层和第二层的功能，可以根据运营商的需求来选择。UMTS 并没有定义骨干网业务，可以利用现有的标准。 2.2 UMTS QoS 的要求 对UMTS QoS 的一般要求可以概括如下: (1) QoS 的参数不应受到一个或几个外部QoS 控制机制的限制，但QoS 应该能通过使用UMTS 规定 关于下班后关闭电源的规定党章中关于入党时间的规定公务员考核规定下载规定办法文件下载宁波关于闷顶的规定 的控制机制来提供不同级别的QoS; (2) 所有的QoS 参数必须有明确的意义; (3) QoS 机制必须允许有效的使用无线容量; (4) 允许核心网和接入网的独立演进; (5) 允许UMTS 网的演进; (6) 所有的QoS 参数组合必须有明确的意义。 (7) UMTS QoS 控制机制应该在MS 和3G 网关节点对等的基础上提供QoS 参数控制; (8) UMTS QoS 机制应该在应用需求和UMTS 业务之间提供映射; (9) UMTS QoS 控制机制应该能够和现有的QoS 方案 气瓶 现场处置方案 .pdf气瓶 现场处置方案 .doc见习基地管理方案.doc关于群访事件的化解方案建筑工地扬尘治理专项方案下载 之间有效的交互工作; (10) QoS 应该能够通过UMTS 定义的控制机制来提供不同级别的QoS; (11) 在3G 服务节点内，对所有的分组模式通信需要采用基于会话的方法，UMTS QoS必须紧密地链接，本质特征为每个地址多个QoS 流; (12) UMTS 应该提供有限的QoS 定义; (13) QoS 方案引起的开销和额外的复杂性应该尽可能的低，网络中状态信息的传输和存储也应尽可能的少; (14) QoS 应该支持频率的有效利用; (15) QoS 的参数需要支持不对称的承载业务; (16) 应用或MS 和3G 网关节点中的特殊软件应在其数据传输中指明QoS 值; (17) QoS 的作用应该是动态的; (18) QoS 的参数数目应尽可能的少。 2.3 UMTS QoS 的分类及其属性 上面的分层结构需要对提及的每一种承载业务定义QoS 属性(参 数组)，这些属性用来把端到端的QoS 要求映射为对每个承载业务的要求。 业务级别即QoS 的分类，为基于业务对实时性的要求对业务的分类，共有四种，按照实时性要求从严到宽的排列为会话级、交互级、流级和背景级，他们的基本特征和典型应用如表2 所示。从表1 可知，不同的业务级别有不同的QoS 属性要求。 2.4UMTS QoS 的管理功能 所有UMTS 实体的QoS 管理功能将确保UMTS 各承载业务接入点之间协商的业务，同时，通过和UMTS 外部业务之间的翻译和映射提供端到端的业务。 (1) 控制平面UMTS 承载业务的QoS 管理功能, 等同于控制平面的业务建立、更改和保持功能，提供所有用户平面的QoS 管理功能的相关属性。业务管理同样可以在其他情况下提供业务，他可以通过属性翻译向下层发出业务请求，也可以通过询问其他的控制功能实体来接收业务提供的许可信号。 翻译功能，将UMTS 承载业务控制的内部业务原语和外部网络接口的业务控制所需各种协议进行转换。包括UMTS 承载业务属性和外部网络业务控制协议的QoS 参数的转换。接入/能力控制，保存所有关于网络实体的可用资源和分配给UMTS 承载业务的资源信息。预约控制，检查UMTS 承载业务用户使用具有特定QoS 属性的业务请求的管理权限。 (2) 用户平面UMTS 承载业务的QoS 管理功能用户平面的QoS管 理功能将信令和用户数据业务量保持在一定的限度内，用特定的QoS属性值来定义。 映射功能，为每个数据单元提供一个特定的标记，该标记在承载业务传送该数据单元时用来接收预期的QoS。 分类功能，若MT 已经建立了多个UMTS 承载业务，他根据相关的QoS 属性将数据单元分配给MT 已经建立的业务。 资源管理，将可用资源在共享该资源的所有业务间根据所需的QoS 进行分配。业务量调节器，使业务所协商的QoS 与数据单元业务量相一致。 3. 3G 空中接口QoS 为了满足不断增长的随时随地接入因特网的需求，因特网业务必须无缝地扩展到MTs，这就需要在3G 空中接口中引入QoS 机制来优化对Internet 业务的支持。同时，3G 无线网络也需要对现有的业务以及即将出现的业务提供良好的支持。因此，3G 空中接口QoS 机制必须具有一定的灵活性以便于新业务的推出，还应在业务提供者和终端用户之间提供一个有效的协商途径。 3.1 CDMA 空中接口QoS 在3G 标准中，空中接口多数采用了成熟的CDMA 技术，现有的CDMA 空中接口QoS方案只满足特定的应用需要。典型的，他们只为实时的应用提供硬QoS 保护，而对非实时的应用则采用最大努力(best effort)发送机制。 为了使优化网络对Internet 业务的支持和在网络推出新业务时 有一个灵活的QoS机制保护，文献【3】提出了一种3G CDMA 空中接口QoS 方案，该方案基于对业务的分级。我们可以把一个系统提供的业务分为三个级别:premium、gold 和silver，每个级别为他的用户提供一个特征性能，即组行为(Group Behavior)。Premium 业务可以在任何时候提供协商的带宽，而不需考虑空中接口的信道特性(阻塞、干扰和衰落等)。其他的两类业务级别都带有一个弹性系数，当空中接口出现阻塞时，他们将根据所带的弹性系数来调整为用户分配的带宽，这样就可以减轻阻塞。 一个级别的组行为是由功率控制和扩频控制来实现的，实现的途径有多种，如可以通过基于目标信干比(SIR)的自适应功率控制和自适应扩频因子控制来实现。这一方案既可以用于CDMA系统的上行链路，也可以用于下行链路，通过使用基于级别的带宽调度方案来 实现CDMA空中接口的不同QoS。使用这一QoS 方案，3G 运营商可以定义自己的业务等级集，选择最恰当的途径实现组行为，同时可以采用按业务级别计费的方案。由于每组都有特定性能(延迟和吞吐量)，很容易实现空中接口的业务协商。 需要注意的是，为了控制的方便和上面带宽调度方案的实现，必须拥有一个能够表现CDMA 空中接口能力的无线资源分配方案。该无线资源分配方案不仅能够运用于常规的发送/接收机，也应能够运用于那些采用了诸如多用户接收和智能天线等性能增强技术的发送/接收机。 3.2 TDMA 空中接口QoS 在3G 无线网络中，也有基于TDMA的空中接口，如EGPRS(增强通用分组无线业务)。EGPRS 为GSM 和TDMA 的一个演进，采用了基于TDMA 的分组交换无线技术和一个演进的分组交换GPRS 核心网。当前的EGPRS 协议采用的是GPRS 核心网，并引入了一个新的空中接口，EDGE(增强数据全球演进)。 为了在3G 无线网络中支持不同的业务，需要在TDMA 空中接口中引入QoS 机制。文献【4】对3G EGPRS 中支持不同业务级别的不同调度机制进行了讨论，对两种加权循环类型的调度法进行了研究:无线接入网(RAN)中无线感知(radio-aware)分组调度法和CN 边缘的常规分组调度法。结果显示，对于EGPRS 系统，如果在调度时一起使用无线链路状况和无线资源管理能够提高系统的整个延时性能。但对不同的业务级别使用加权循环调度法并不适用于一个干扰受限环境。同时多时隙的分配也可以用来提供不同的业务。 4. 3G RAN 的QoS UMTS/IMT-2000 的基本概念是把接入的功能和核心网功能分开，RAN 为所有的MTs提供了一个接入CN 的平台。对CN 来说，那些依赖于无线接入技术的功能和移动性功能是不可见的。目前3GPP 定义的接入网有分别基于WCDMA和EDGE无线接入技术的UTRAN和GSM/EDGE 无线接入网(GERAN)。 在3G RAN 中，必须有连接诸如基站和无线网络控制器等网络单元的传输技术。综合应用自身对QoS 的不同要求和先进的无线控制 功能强加于应用的要求，传输技术必须为不同级别的业务提供不同的QoS。传输承载必须支持多种QoS 的要求和业务特性。 4.1 基于ATM的传输方案 在当前各种分组网络技术中，ATM是对QoS 的支持相对成熟的一种方案。在UMTS 的第一个发布版本中，UTRAN 选中了ATM/AAL2(ATM 自适应层2)作为他的传输技术。为了满足UTRAN 传输层对QoS 的严格的要求，必须对业务管理、资源管理等给以特别的关注。 文献【5】列出了UTRAN 中几种ATM/AAL2 传输的性能及其设计方法，研究了严格的延迟要求对ATM/AAL2 传输所需带宽的影响。得出的结论为ATM/AAL2 技术能够满足严格的WCDMA UTRAN QoS 要求。 4.2 基于IP 的传输方案 3G RAN 的网络单元不仅可以通过ATM/AAL2 技术来互连，也可以通过IP 技术来互连。在RAN 中之所以选择IP 传输方案，主要出于下面的考虑:首先，IP QoS 管理机制已经近于成熟;其次，IP 作为一个网络层协议，是独立于链路层/物理层设计的，所以可以和各种低层协议协同工作;再次，IP 已经成为网络中各种业务分组的基准;最关键的是3G CN 是基于IP 的。 目前的IP 网络都是面向对延迟不敏感的数据应用的，所以，必须加以改进，对基于IP的传输方案提供包括延迟、抖动和丢失等QoS 的支持。IETF 在这方面做了许多工作:实时分组流的传输协议RTP，IP 网络上实时信令的传输SigTran，具有QoS 保护的集成业务结构IntServ，集成服务/资源预留协议RSVP，业务区分结构DiffServ， 减小开销的IP 头压缩IPHC等。 3GPP 和移动无线Internet 论坛(MWIF)都在进行这方面的研究，3GPP 的研究结果可以在文献【6】中获得，MWIF 的研究成果则可以在文献【7】中获得。 5. 结束语 目前，致力于3G 标准化的两个组织3GPP 和3GPP2 仍然在对3G 中一些关键技术进行研究，并使其中的一些成为标准。虽然现在3G 还没有在世界范围内铺展开，广泛铺开的是2G 向3G 的过渡网络，如GPRS 和CDMA 1x 等。但是随着时间的推移，业务的需要，3G必将在世界范围内广泛铺开。因为3G 支持各种各样的业务，而用户的要求也越来越高，所以必须为业务提供QoS 保护。3G 的最终目标是一个全IP 的网络，这也决定了QoS 将是是3G 的一个不可或缺的部分。所以3G 的QoS 将是3G 研究工作的一个重点，而3G 的最终建设也必将把保证业务的QoS 放在首位。 参考文献 [1]3GPP TS23.107 V3.6.0。 QoS的概念和体系结构。 2001.4。 [2]3GPP TS22.105 V3.9.0。服务和服务能力。 2000.6。 [3] JY.Guo和H. Chaskar。差异化服务质量框架 3G CDMA空中接口。 IEEE WCNC2000～芝加哥～9.2000 [4]J.Cai.通过PacketSheduling在EGPRS提供差异化服务。2000年 11月 [5] JS.Nananukul.在UTRAN中的ATM/ALL2Transport在性能和设计的al.Some问题。 IEEE WCNC2000～芝加哥～9.2000 [6]3GPP TR25.933。 UTRAN工作任务的技术报告中的IP传输。 [7] JMWIF～TR。IP RAN方案在3G移动通信系统。