下一代网络的业务互通体系结构

以IP为基础的因特网的出现对传统的电信网络带来了巨大的冲击,它的开放性和业务的灵活性为电信网进一步的发展指出了一个方向.但是,由于IP在提供具有质量保证的等级业务方面缺乏技术的保障;局域网技术、广域网技术的发展使得原来被认为功能简单的第二层传输网络具有越来越强的业务能力,例如QoS、多播、VPN以及安全管理能力,将导致多接入、多业务的下一代网络端到端业务控制和业务集成越来越复杂,使得我们需要重新审视网络互连和业务集成的基本思路,建立下一代网络的新的业务概念.本文对这个问题进行了初步的探讨,结论是:下一代网络具有新的集成业务体系结构,其中的关键是业务互通问题;其中IP用于网络互联,SIP用于建立终端和服务器间的业务会话,提供业务之间的互作用,实现端到端业务能力的集成和最终应用的集成需要新的网格业务技术;下一代网络除要有分别支持网络互联、会话建立和业务集成的能力以外,还必须建立网络、会话和业务之间的新的互作用关系,使得下一代网络的目标得以实现.     

下一代网络业务提供模式及发展趋势

电信网业务的提供模式经历了一个逐步演进的过程，呈现出由分散到集中、由综合到分离、由封闭到开放的发展趋势。适应这一趋势，下一代网络将有会话初始协议（SIP）服务器、开放业务接入（OSA）应用服务器和智能网3种业务提供模式，为用户提供各类业务和应用。随着宽带接入和互联网的普及，下一代网络将不再提供单一的通信服务，将作为国家重要基础设施，为用户提供各类信息服务，业务提供模式将更加开放化、多元化、个性化。     

下一代电信网业务节点的发展趋势

本文首先阐明发展下一代电信网是历史的必然 ,然后分析了现有电信网向下一代电信网的演进策略 ,接下来重点探讨了下一代电信网业务节点的要求以及五类不同业务节点的结构、功能、特点及其发展趋势     

下一代光网络中光路的快速建立

文章针对下一代光网络中光路快速建立的问题,介绍了IP-over-optical的网络体系结构,并在此基础上介绍了动态RWA问题和综合解决RWA问题的动态和半动态寻路算法,讨论了这两种算法的容错性能。     

下一代光网络中的多粒度光交换技术

论述了多粒度光交换技术(MGS)的特点，通过计算比较端口数，定量分析使用MGS能简化光交叉连接器(OXC)的结构。提出了基于MGS的多粒度分层路南、多粒度信令机制以及链路管理技术。讨论了引入MGS对自动交换光网络(ASON)的生存性和流量工程等系统应用方面的影响。     

无线Mesh网络QoS保障技术综述

首先,简要回顾了无线Mesh网络的基本概况,分析了在无线Mesh网络中提供QoS保障的必要性和重要意义。然后,系统地介绍了无线Mesh网络的物理层、MAC层和路由层QoS保障技术以及跨层QoS设计技术的国内外研究现状,对其进行了细致而科学的分类。最后,给出了它们的研究难点和研究方向。     

下一代网络业务体系架构研究

本文提出了一种应用于下一代网络的面向服务的业务体系架构。该架构的优势在于：通过开放业务能力实现了业务应用的灵活创建,从而缩短了业务生成周期,降低了开发成本;同时,通过引入面向服务的思想进行开放能力互联大大增加了业务网的健壮性。     

Broadband Wireless Access Solutions - Progressive Challenges and Potential Valueof Next Generation Mobile Networks

The growth in mobile communication will accelerate over the next years. Today most of the mobile subscribers use cellular services only. But this will change in the near future towards broadband wireless access services like WiFi and WiMAX. This paper describes a fundamental overview of the broadband wireless access technologies and outlines the market view, major trends and introduces OFDM technologies. New developments for integration of broadband wireless access into the operators' infrastructure are also discussed.     

软交换业务交易平台:下一代电信网络业务控制体系结构(下)

通信网络在Internet技术的推动下向支持动态的个性化电信业务的多业务电信网络发展，电信市场的开放要求电信运营商提供适应市场需要的可运营的电信业务，本文对基于IP基础设施的下一代电信网络的业务控制体系结构进行了研究，分析了对下一代电信网络控制结构的需求，描述了下一代电信业务的业务平面，提出了下一代电信业务交易平台的结构特征和功能特征，并对当前软交换技术的各种进展进行了对比，介绍了我们建立的基于下一代业务体系结构的软交换交易平台解决方案（STSB），提出了对今后网络业务控制体系结构研究的建议。     

位置服务平台解决方案

本文讨论了东信北邮信息技术有限公司位置服务平台的系统总体结构设计、功能模块设计、进程拓扑图.     

Editorial: Intelligent and Holistic Solutions for Next Generation Wireless Networks

Mobile Networks and Applications -     

A Framework for Seamless Roaming Across Heterogeneous Next Generation Wireless Networks

In the future, wireless and mobile users will have increased demands for seamless roaming across different types of wireless networks, quality of service guarantees and support of different types of services. This awareness has led to research activities directed towards inter-system and global roaming and can be noticed in the numerous products like multimode handsets, inter-working gateways and some ongoing standards and research work on signaling protocols for inter-system roaming. This article proposes a global mobility management framework. The framework is like an overlay network comprising of Inter-System Interface Control Units IICU to support inter-network communication and control for Location Management. The protocols and functions of this framework will be distributed and exist partly within the wireless networks and partly within the core-network. A hierarchy introduced among the IICUs will accommodate for the varying mobility coverage required by the mobile user. The IICU may be configured to perform various functions depending on its placement in the hierarchy of the framework. This approach aims to optimize across call set up delays, signaling traffic, database processing, handoff facilitation for seamless roaming and QoS mapping and negotiations as the user moves across different wireless networks. It avoids centralized database dependency with its associated single-point bottleneck and failures. We restrict our analysis of the framework to a 2-network and a 3-network roaming scenario. The presentation has been further restricted to cost and delay analysis of the location update and call delivery procedures. We have taken into account the signalling requirements when the mobile user roams across networks with and without an active call. Nirmala Shenoy is Associate Professor at the Information Technology department at RIT. She has several years of teaching and research experience while working in Germany, Singapore and Australia before she moved to USA. She is an avid researcher in the wireless networks area and has technically led several wireless network projects to success. She holds a Ph.D. in computer science from the University of Bremen, Germany, Masters in Applied Electronics and Bachelors in Electronics and Telecommunications Engineering both from Madras University in India. Professor Shenoy is interested in research in the area mobility management and modeling for wireless networks, Quality of service in wireless networks and the Internet.     

A New Positioning Method for Location-Based Services in Wireless LANs

Positioning techniques are crucial to achieve location-based services. Location estimation systems using received signal strength in wireless LANs （Local area network） have attracted great attention for the advantages of low cost, ubiquitous coverage and ease of deployment. Existing methods neglect the difference between contributions of access points to location estimation results. Signals from far access points travel long distance and thus more uncertainty is added to the receive signal strength. This paper proposed a positioning method based on the Dempster-Shafer evidence theory. Different belief was assigned to signal strength from different access points according to its importance to location estimation. We carry out a series of experiments to evaluate the method and compare with other related work. Experimental results show that the approach gives a higher degree of positioning accuracy.     

Providing Real-Time Service in CDMA Wireless Networks

Medium Access Control (MAC) protocol design plays a very important role in the design of wireless networks. In this paper, we propose a new MAC protocol to provide real-time service for a CDMA wireless network. This protocol has been designed based on the distributed queuing random access protocol for CDMA wireless networks (DQRAP/CDMA). As real-time scheduling schemes have been introduced into the protocol design, the new protocol has an ability to accommodate real-time traffic in the CDMA wireless networks. A series of simulation experiments have been carried out to evaluate the performance of the proposed protocol. The results reveal that the proposed protocol can efficiently provide real-time service to the traffic composed of time constrained messages in the CDMA wireless networks.     

一种数字宽带新业务:广告点播

传统的广告模式为电视广告、户外广告、互联网广告以及报纸、广播等其他媒体承载广告。随着IPTV、3G基础网络的逐步建设，广告业务的进一步发掘已成为运营商、客户关注的焦点。当前的信息技术、网络环境、市场环境已经话合于发展一种新的广告模式：广告点播（AOD），相对于广告轮播，AOD有更强的互动性、针对性、灵活性。相对于视频点播（VOD），AOD主要采用广告客户买单的资费方式。使用灵活多样的接入终端。贴近了企业、商家及用户的需求，更适于在通信网络上应用。AOD将作为重要业务大力促进电信网络发展，提升运营商盈利能力。     

IMS与下一代电信业务网

当前IP多媒体子系统（IMS）为核心的电信目标网络架构缺乏大规模现网部署的实际验证,并面临互联网技术的激烈竞争。在推动IMS业务商用的过程中,业务交付平台（SDP）正在向一个更加融合开放的业务提供环境（SDE）方向发展,并成为下一代电信业务网络发展的主流方向。中兴通讯的下一代业务网（NGSN）概念,通过整合各种网络业务能力,实现数据、业务、能力和管理的统一,从而能够快速提供各种增值业务、协助运营商在价值链中处于主导地位,很好的满足了电信运营商业务网络的发展需求。     

下一代通信网络中基于策略机制的无线资源管理

下一代无线通信系统是一种异构的网络体系,集成多种无线接入技术（Radio Access Technology,RAT）的同时提供多种窄带和宽带多媒体业务。这样的网络环境需要先进的RRM方法来处理复杂多变的无线信道、网络资源的动态配置及保障不同特征业务的服务质量（QoS）,给无线资源管理（Radio Resource Management,RRM）带来了巨大的技术挑战。本文通过引入对网络进行策略控制的思想,提出了一种基于策略机制的通用方法,致力于解决下一代异构（heterogeneous）网络中的无线资源管理。文中着重讨论了基于策略机制的网络接入控制、切换,以及基于策略机制的QoS管理,给出了各功能模块的工作原理和通信过程的分析与设计。     

QoS Provisioning in Wireless IP Networks

This paper deals with quality of service (QoS) provision in wireless IP networks. QoS provision is particularly challenging in wireless networks, where network resources are generally limited, variable over time and shared. In the design of possible measures to assure QoS one should consider that standardization is well established for the network layer Internet Protocol and for many underlying technologies of frequent use (e.g. IEEE 802.11, BLUETOOTH or HIPERLAN II). Therefore, as far as research on QoS is concerned, there is little room in both the IP and the link-layers for improved IP over wireless interfaces. In this paper we illustrate a solution in which an intermediate Wireless Adaptation Layer (WAL) is transparently interposed between the IP layer and specific link-layer technologies as a solution to provide QoS. The WAL addresses two main issues: (i) compensation for channel impairments in different platforms in order to enhance wireless channel reliability and (ii) implementation of traffic control and packet scheduling mechanisms to satisfy bandwidth and delay requirements, as well as to enforce a general principle of fairness among the IP associations contending for network resources and achieve optimal exploitation of transmission capacity. The WAL consists of a set of modules, each one in charge of a specific task, which can be enabled or disabled depending on the specific network environment. The novelty of the WAL approach is its capability of adapting itself to different wireless interfaces selecting performance enhancing modules for specific networks. This requires to modify the standard TCP/IP protocol stack by introducing an intermediate layer between the IP layer and the Data Link layer, with performance enhancement purposes. This paper focuses on two modules in particular, namely a traffic control module, which is in charge of performing congestion control and channel state dependent scheduling (CSD) packet scheduling, and a forward error correction (FEC) module, which compensates for channel impairments. This paper presents the proposed architecture provided with these modules and reports some measurements and simulations highlighting benefits resulting from the use of such modules.     

下一代网络业务架构的探讨

随着网络技术的飞速发展,原有的网络已不能满足用户的需求。以软交换设备为核心,能够提供话音、视频、数据等多媒体综合业务,采用开放、标准的体系结构,能够提供丰富业务的下一代网络(NGN)应运而生,且一度成为人们关注的热点。文章通过对NGN业务演进策略的分析得出NGN业务架构应满足的性能要求,然后根据现有的各项NGN业务技术构建了NGN业务架构,实现了传统电信业务和Internet业务的融合。