GPRS网络优化初探

GPRS通过增加一些新的功能单元,使得在现有的GSM系统上,手机终端用户能够进行高述分组数据通信的业务;同时,GPRS也为第二代移动通信平滑过渡剑第三代移动通信提供了一个过渡的平台。GPRS网络的建设是向第三代网络演进过程中迈出的第一步,第三代移动通信网规范R99／R4／R5核心网分组域都是基于增强的GPRS网络,在核心网建设上有紧密的延续性。因此,GPRS是GSM向第三代网络发展过程中一个不可逾越的一个阶段。     

CDMA核心网络的演进路线

CDMA核心网的发展面临着路线选择的问题,本文详细讨论了核心网电路域和核心网分组域的演进路线.核心网电路域有两种路线可以选择,本文对每一种路线需要考虑的问题进行了分析.分组域作为IMS的承载网络,需要解决安全、QoS以及业务感知等问题,本文对分组域演进的需求和目标进行了分析,讨论了未来分组网络需要重点解决的问题.针对未来CDMA核心网络采用IMS还是分组演进网络的问题,从技术、标准、设备的角度分析了IMS的成熟性,最终得出了CDMA核心网络演进的总体路线.     

cdma2000系统和WCDMA系统分组数据业务的比较

简要介绍了第三代移动通信系统中的cdma2000系统和WCDMA系统的分组业务,并对两种系统分组业务的网络结构、分组业务协议和QoS等进行了比较。     

移动核心网发展浅析

移动通信自从诞生以来已历经了三十多年的飞速发展。文章简要阐述了第一代到第三代及至目前正在研究中的新一代移动核心网的特点,在全面分析了移动核心网的发展趋势后指出：移动核心网在未来将具有全IP化、融合及智能化的主要特征,最终形成一个异构的以用户业务数据为中心的融合网络。     

第三代移动通信系统UMTS的概况

通用移动通信系统是欧洲的第三代移动通信系统标准,其一般结构从物理和功能的角度进行了模型,在物理方面用域的概念进行模型化,在功能方向用层的概念进行模型化。ＵＭＴＳｐｈａｓｅ１规范的业务包括终端业务与补充业务、传真业务、等。在此基础上对ＵＭＴＳ接入网和核心网的功能以及网安全特性进行了介绍。最后提出了中国第三代移动通信系统的网络结构应采ＵＭＴＳ网络结构,并根据中国的具体条件,逐步建成先进的第三代移动通信     

第三代移动通信系统的QoS和资源管理

最近，移动互联网得到了迅猛发展，第三代移动通信系统为了提供移动多媒体业务，一个关键要素是必须要有QoS。本介绍了UMTS QoS结构和要求，并分别讨论了3G空中接口、无线接入网和核心网中的QoS。     

电信网未来十年的发展方向

三种新的网络体系结构将会是电信网络未来十年的主要发展方向:全光核心网将能更经济、更透明地传送业务流量;3G无线接入将以适当的QoS级别来提供所有的应用,并将逐步实现移动互联网应用;基于QoS的分组网络将会更有效地提供企业分组业务。     

1x EV-DO的QoS控制机制

文章概述了综合业务(IS)的QoS业务模型、RSVP资源预留协议、差分业务(DS)模型的结构;讨论了第三代移动通信无线分组标准之一1xEV-DO关于QoS的前反向的接纳控制、业务接入控制、数据调度和QoS鉴权授权等设计思路,提出了QoS功能模块的网络结构和实现。     

第三代移动通信系统的QoS和资源管理

最近,移动互联网得到了迅猛发展,第三代移动通信系统为了提供移动多媒体业务,一个关键要素是必须要有QoS。本文介绍了UMTSQoS结构和要求,并分别讨论了3G空中接口、无线接入网和核心网中的QoS。     

基于3G的IP QoS机制研究

随着第三代移动技术的实现和移动通信与IP网的融合，尤其是用户对多媒体业务需求的高速增长，具有明确的QoS要求已成为3G网络的一个重大特征。3G核心网的端到端QoS问题早已成为运营商们关注和研究的重点。各大国际标准化组织都针对该问题制定了相关标准，在制定的各版3G标准中，都对QoS进行了相应的规划。     

A flexible and distributed architecture for adaptive end-to-end QoS provisioning in next-generation networks

A novel distributed end-to-end quality-of-service (QoS) provisioning architecture based on the concept of decoupling the end-to-end QoS provisioning from the service provisioning at routers in the differentiated service (DiffServ) network is proposed. The main objective of this architecture is to enhance the QoS granularity and flexibility offered in the DiffServ network model and improve both the network resource utilization and user benefits. The proposed architecture consists of a new endpoint admission control referred to as explicit endpoint admission control at the user side, the service vector which allows a data flow to choose different services at different routers along its data path, and a packet marking architecture and algorithm at the router side. The achievable performance of the proposed approach is studied, and the corresponding results demonstrate that the proposed mechanism can have better service differentiation capability and lower request dropping probability than the integrated service over DiffServ schemes. Furthermore, it is shown that it preserves a friendly networking environment for conventional transmission control protocol flows and maintains the simplicity feature of the DiffServ network model.     

A Study on Differentiated Service Queuing Scheme with an Overflow Buffer Allocation Within a UMTS Core Network

According to the QoS features of the four types of UMTS traffic, this study proposes a priority-based queuing scheme to support differentiated services among all UMTS traffic; it bases on packet transmission priorities of four types of UMTS traffic to handle packets forwarding in a gateway within a UMTS core network. In the proposed queuing scheme, a static dedicated logical queuing buffer allocation and a dynamic overflow buffer allocation are used to support packet enqueuing/dequeuing jobs. In this study, the ns2 network simulator is used as a simulation platform and different categories of simulation scenarios are executed. Moreover, the IETF DiffServ scheme is used as a comparison to understand the packet forwarding performance of the proposed scheme. By analyzing simulation data, two important points can be drawn. The proposed queuing scheme supports a differentiated packet forwarding behavior among four types of UMTS traffic. And, the differentiated packet forwarding behaviors with the proposed queuing scheme are similar to the packet forwarding behavior with the IETF DiffServ scheme.     

DiffServ resource allocation for fast handoff in wireless mobileInternet

The next-generation wireless networks are evolving toward a versatile IP-based network that can provide various real-time multimedia services to mobile users. Two major challenges in establishing such a wireless mobile Internet are support of fast handoff and provision of quality of service (QoS) over IP-based wireless access networks. In this article, a DiffServ resource allocation architecture is proposed for the evolving wireless mobile Internet. The registration-domain-based scheme supports fast handoff by significantly reducing mobility management signaling. The registration domain is integrated with the DiffServ mechanism and provisions QoS guarantee for each service class by domain-based admission control. Furthermore, an adaptive assured service is presented for the stream class of traffic, where resource allocation is adjusted according to the network condition in order to minimize handoff call dropping and new call blocking probabilities     

基于区分服务的边缘路由器的服务质量

Internet real-time multimedia communication brings a further challenge to Quality of Service （QoS）. A higher QoS in communication is required increasingly. As a new framework for providing QoS services, Differentiated Services （DiffServ） is undergoing a speedily standardization process at the IETF. DiffServ not only can offer classified level of services, but also can provide guaranteed QoS in a certain extent. In order to provide QoS, DiffServ must be properly configured. The traditional DiffServ mechanism provides classifier for edge router to mark the different traffic streams, and then the core router uses different Drop Packet Mechanisms to drop packets or transmit data packets according to these classified markers. When multiple edge routers or other core routers transmit data packets high speedily to a single core router, the core router will emerge bottleneck bandwidth. The most valid solution to this problem is that the edge router adopts drop packet mechanism. This paper proposes an Modified Edge Router Mechanism that let the edge router achieve marking, dropping and transmitting packets of hybrid traffic streams based on DiffServ in a given bandwidth, the core router will only transmits packets but won＇t drop packets. By the simulation of ns2, the modified mechanism ensure the QoS of high priority traffics and simplify the core router, it is a valid method to solve the congestion of the core router.     

UMTS核心网中基于区分服务的QoS控制模型

3G新业务的发展，要求UMTS提供端到端QoS控制。文章构建了在UMTS核心网中为不同业务类提供QoS保证的区分服务模型，提出了从UMTS业务类到DiffServ域服务等级的映射方案，设计了一种新的队列调度算法，采用优先级和分离机制，在流量调整器配合下可满足不同业务类的QoS要求。最后，通过模拟实验证明了模型的有效性。     

Quality of Service Management in GPRS-Based Radio Access Networks

In this article, the performance and capacity gain achievable with quality of service (QoS) management in packet switched radio networks based on the General Packet Radio Service (GPRS) are examined. Both the functions defined in the GPRS specification for QoS support and implementation-specific strategies for subscriber- and application-based Connection Admission Control (CAC) and scheduling are introduced. The feasibility of QoS provisioning in mobile core networks with use of DiffServ compared to present IP technology realizing a pure Best-effort service is examined in addition. To achieve this, simulation results of GPRS performance and system measures for different load situations are produced with the simulation tool GPRSim that models the realistic traffic behavior of a GPRS network.     

Translation of specification units between IP and ATM quality of service declarations

An integral part of any network quality of service (QoS) system are its QoS declarations. QoS declarations consist of service classes, parameters, and specification units. QoS declarations are a component of the QoS architecture, as such they are a source of heterogeneity stemming from the fact that different QoS systems may be based on different QoS architectures and thus use different QoS declarations. A particular problem in that domain is the translation of specification units for QoS systems that are based on different forwarding technologies with respect to variable vs fixed packet sizes, i.e. packet vs cell switching. This is a problem that can be dealt with generically such that its solution can be applied to several situations of technically heterogeneous QoS systems like an RSVP/IntServ—or DiffServ—over an ATM‐based system. While straightforward translations have been proposed, we investigate how more efficient translations can be achieved by using a slight but effective modification of existing AAL framing schemes as well as making use of statistical knowledge about packet size distributions. Copyright © 2003 John Wiley & Sons, Ltd.     

Multicast Support in DiffServ Using Mobile Agents

Many multicast applications, such as video‐on‐demand and video conferencing, desire quality of service (QoS) support from an underlying network. The differentiated services (DiffServ) approach will bring benefits for theses applications. However, difficulties arise while integrating native IP multicasting with DiffServ, such as multicast group states in the core routers and a heterogeneous QoS requirement within the same multicast group. In addition, a missing per‐flow reservation in DiffServ and a dynamic join/leave in the group introduce heavier and uncontrollable traffic in a network. In this paper, we propose a distributed and stateless admission control in the edge routers. We also use a mobile agents‐based approach for dynamic resource availability checking. In this approach, mobile agents act in a parallel and distributed fashion and cooperate with each other in order to construct the multicast tree satisfying the QoS requirements.     

A Study on a Differentiated Service Queuing Scheme Based on Transmitted Bytes Within a UMTS Core Network Gateway

Universal mobile telecommunications system (UMTS) is a popular 3G system to support network applications full of variety. According to the quality of service (QoS) features of four types of UMTS traffic, this study proposes a BBQ (byte-based queuing) scheme to handle a UMTS packet forwarding process in differentiation. With the BBQ scheme, four types of UMTS traffic depend on their QoS features to receive differentiated packet forwarding performance within a UMTS core network. Several scenarios are simulated to realize the packet transmission performance of the BBQ scheme. Moreover, a packet transmission performance comparison between the IETF RIO scheme and the BBQ scheme is discussed in this study. The simulation results show that a differentiated packet forwarding behavior among UMTS traffic can be provided by the BBQ scheme with low cost operation/architecture; this demonstrate the effectiveness of the proposed queuing scheme.     

上下文感知自治QoS框架中的新型包标记算法

Autonomic networking is one of the hot research topics in the research area of future net- work architectures. In this paper, we introduce context-aware and autonomic attributes into DiffServ QoS framework, and propose a novel autonomic packet marking （APM） algorithm. In the proposed autonomic QoS framework, APM is capable of collecting various QoS related contexts, and adaptively adjusting its behavior to provide better QoS guarantee according to users＇ requirements and network conditions. Simulation results show that APM provides better performance than traditional packet marker, and significantly improves user＇s quality of experience.