IMS、WiMAX及其融合

1 IMS 最近几年,通信界有两个吸引眼球的名字:“IMS”和“WiMAX”。IMS最早出现在3GPP的文稿中,其中文名称为IP多媒体业务。在3GPP的Release5中,第一次真正定义了IMS域;2004年,ITU决定在3GPP的IMS基础上发展NGN,使NGN有了一个明确的体系结构,也促进了下一代固定和移动通信网络的融合。     

QoE-aware mobile IPTV channel control algorithm over WiMAX network

In this paper, we present an effective IPTV channel control algorithm that improves the quality of experience for subscribers to mobile IPTV services over WiMAX network. We consider the video quality of TV channels and the channel zapping time as quality of experience metrics. The proposed algorithm controls the channel distribution state and the target bit rate of TV channels based on the channel preference information of subscribers to achieve an effective trade-off between channel zapping time and video quality. Finally, simulation results are provided to demonstrate the performance of the proposed system.     

WiMAX与3G移动通信系统的融合及应用

探讨了WiMAX与移动通信系统的融合及应用问题,重点分析比较了WiMAX与3G技术,并阐述了网络融合的必要性和可行性,最终给出网络融合及应用的方案.     

A novel fountain code-based mobile IPTV multicast system architecture over WiMAX network

In this paper, we present a novel fountain code-based mobile IPTV multicast system architecture over WiMAX network. In the proposed system, the transmission algorithm at a base station determines the control parameters of a fountain-encoded IPTV multicast stream adaptively to the wireless link states of subscribers in order to provide a stable IPTV service with minimum resource usage on WiMAX network, and the channel grouping algorithm at a server makes near-optimal channel grouping based on channel selection preferences to pursue an effective tradeoff between the channel zapping time and the processing complexity of a subscriber. Finally, experimental results are provided to show the performance of the proposed system.     

A narrow-frame antenna for WWAN/LTE/WiMAX/WLAN mobile phones

In this paper, we present a novel narrow-frame antenna with a size of 75 × 8 × 5.8 mm³ for 5.7 in. mobile phones. The antenna mainly consists of a monopole with four branches that are coupled to a two-branch grounded strip. Our antenna is able to cover more bands than other narrow-frame antennas by excitation of several resonant modes. The improved range of the antenna covers the following eleven bands: LTE700, GSM850, GSM900, DCS, PCS, UMTS, LTE2300, LTE2500, LTE3400 (3400–3800 MHz)/WiMAX3.5 GHz (3400–3650 MHz), WLAN5.2 GHz (5150–5350 MHz) and WLAN5.8 GHz (5725–5875 MHz). Another advantage of the proposed antenna is that it does not need any lumped element to match the antenna. The working principles of the proposed antenna are thoroughly studied. A prototype of the proposed antenna is fabricated and measured, with the results in good agreement with the simulation results.     

Performance study of mobile WiMAX network with changing scenarios under different modulation and coding

WiMAX—the Worldwide Interoperability for Microwave Access is a promising technology for offering high‐speed data, video and multimedia services over mobile platform evolving toward all IP networks. The increasing demand of WiMAX for VoIP and high‐speed multimedia is due to the simplicity of installation and cost reduction compared with the traditional wired DSL cable. The challenges to service providers lie with the Quality of Service (QoS) under varying fading environment while at the same time maximizing for resource utilization. In this paper, a rigorous and comprehensive performance study of mobile WiMAX has been made with respect to adaptive modulation and coding techniques considering the variation in the speed of the mobile, path‐loss, scheduling services and application type for comparing with the fixed type of modulations. The OPNET 14.5.A modeler for WiMAX platform has been used as simulator for adaptation at the physical layer of the transmission in WiMAX OFDMA structure. Observation reveals that dynamic adaptation of modulation and coding schemes based on channel condition enables better QoS while consuming low overall bandwidth of the system. Copyright © 2011 John Wiley & Sons, Ltd.     

WiMAX加速移动互联网时代的到来

WiMAX（微波接入全球互通）是一种无线宽带数据传输系统。目前，该技术正在计划和试用阶段，同时，用于首次区域性实验的相关无线网络也已经开始建设，企业正与从事WiMAX相关领域研究的专家们进行着密切的合作。     

基于移动通信网络的安全框架探究

本文通过构建开放度模型,对移动通信网络安全重点威胁进行信任度分析,并通过安全平面的方式对其进行威胁的划分,从而对整体的移动网络安全环境进行评估,以此为移动网络通信的安全处理奠定基础。     

基于移动通信网络的安全框架探究

本文通过构建开放度模型,对移动通信网络安全重点威胁进行信任度分析,并通过安全平面的方式对其进行威胁的划分,从而对整体的移动网络安全环境进行评估,以此为移动网络通信的安全处理奠定基础。     

An overview of next-generation mobile WiMAX technology - [WiMAX update]

The growing demand for mobile Internet and wireless multimedia applications has motivated the development of broadband wirelessaccess technologies in recent years. Mobile WiMAX has enabled convergence of mobile and fixed broadband networks through a common wide-area radio-access technology and flexible network architecture. Since January 2007, the IEEE 802.16 Working Group has been developing a new amendment of the IEEE 802.16 standard (i.e., IEEE 802.16m) as an advanced air interface to meet the requirements of ITU-R/IMT-advanced for 4G systems, as well as for the next-generation mobile network operators. Depending on the available bandwidth and multi-antenna mode, the next-generation mobile WiMAX will be capable of over-the-air datatransfer rates in excess of 1 Gb/s and of supporting a wide range of high-quality and high-capacity IP-based services and applications while maintaining full backward compatibility with the existing mobile WiMAX systems to preserve investments and continuing to support first-generation products. This tutorial describes the prominent technical features of IEEE 802.16m and the potential for successful deployment of the next generation of mobile WiMAX in 2011+.     

Wireless link state-aware H.264 MGS coding-based mobile IPTV system over WiMAX network

This paper presents a simple but effective architecture for the transmission of H.264 MGS coding-based IPTV stream over WiMAX network. The proposed system is implemented to provide more subscribers with an enhanced mobile IPTV service considering their wireless link states. In the proposed system, the base layer of the IPTV stream is transmitted with the sparsest modulation scheme and the lowest coding rate to provide IPTV service of minimum quality to as many subscribers as possible. And some parts of the enhancement layer are transmitted with the modulation scheme and the coding rate adaptive to wireless link states of subscribers. Basically, we pursue an efficient tradeoff between the number of subscribers that receive the enhancement layer stream and their IPTV service quality. Finally, experimental results are provided to show the performance of the proposed system.     

Overview of mobile WiMAX technology and evolution

Mobile WiMAX is a fast growing broadband access technology that enables low-cost mobile Internet applications, and realizes the convergence of mobile and fixed broadband access in a single air interface and network architecture. Mobile WiMAX combines OFDMA and advanced MIMO schemes along with flexible bandwidth and fast link adaptation, creating a highly efficient air interface that exceeds the capacity of existing and evolving 3G radio access networks. WiMAX networks, built on all-IP network architecture for plug and play network deployments, can support a mix of different usage and service models. While some consider mobile WiMAX as a candidate for the fourth generation of mobile networks, others view it as the first generation of mobile Internet technologies emerging from a wider ecosystem targeting to extend the success of WiFi over wide area networks supporting mobility. This article provides a high-level overview of mobile WiMAX technology and its evolution roadmap from both radio and network perspectives.     

直放站对移动通信网络的干扰分析

在简单介绍直放站的基本原理的基础上，着重就直放站对移动通信系统所造成的各种干扰进行分析，并提出减少干扰的措施，最后简单介绍几个案例的排查。     

IMS实验网的研究与实现

随着各运营单位的重组和3G牌照的发放,各通信网络的融合与完善对IMS网络发展提出了更高的要求。模拟IMS网络,测试IMS网络,完善IMS网络,使得IMS实验网的搭建变得至关重要。本文介绍了IMS网络的基本结构和功能,采用相关研究工具,组建IMS实验网,部署实现包括P-CSCF、I-CSCF、S-CSCF、HSS和AS等功能实体,实现IMS网络的基本的通信,设置AS提供增值服务。经过测试,验证了系统设计的有效性,为用户带来全新体验。     

基于IMS的3G和WiMAX业务融合的探讨

利用WiMAX技术作为3G有效的接入补充方式,提出了3G和WiMAX业务融合的概念和实现目标,并给出了二者基于IMS的业务融合体系结构.认为实现业务融合的关键技术包括统一的会话管理、统一的用户标识、统一的用户数据及签约信息管理、统一的帐单服务以及统一的业务提供,分析了对应的解决方法.采用IMS作为业务层融合的网络平台,与3G核心网的演进以及基于IMS的固定、移动网络融合的下一代网络演进思路完全一致,对3G网络建设和规划具有很好的参考意义.     

面向未来IMS的新应用

随着中国各运营商逐步完成IMS网络部署,IMS技术带给我们巨大的新业务拓展空间.本文主要探讨了未来IMS网络到底能为我们提供什么样的体验,提出了融合话音业务、RCS、IPTV、高清视频将成为IMS的应用热点,并从标准的进展到新业务应用的实现架构进行了分析和论述.     

Integration of intelligent network services into future GSMnetworks

This article introduces various difficulties and issues in the basic scenario of integrating intelligent networks (INs) and the Global System for Mobile Communications (GSM). As an example, implementation of Universal Personal Telecommunications (UPT) is considered. This article does not offer a comprehensive analysis, but rather a tutorial view. The separation of cellular networks and IN is not well suited to provide common mobility-related services. The present signaling systems do not enable transfer of mobility-related parameters, such as the cell identity and international mobile subscriber identity (IMSI). A call connection to the service switching point must be set up every time IN services are used from the GSM network. The same information is stored in several network elements, and service creation and management are complex. With those disabilities in mind, two integration scenarios are introduced and their characteristics are compared. However, the aim is not to give detailed guidance for implementation, but rather to introduce different options and describe their most significant characteristics. It is important to be able to provide mobility-based information directly to the IN. Flexible integration calls for changes both in mobile exchanges and signalling systems. Mobile exchanges will be built with additional IN functionality and, in fact, future signalling systems will better carry mobility-related information. Mobility can be implemented with a rather small investment, provided that there are digital exchanges and transmission systems and the basic infrastructure has already been built. The required intelligence can be offered by using the existing Public Land Mobile Network (PLMN) or IN architecture     

Cross-layer mobile WiMAX MAC designs for the H.264/AVC scalable video coding

To effectively provide the QoS of streaming services in mobile WiMAX systems, this paper proposes a cross-layer design between the streaming server and mobile WiMAX base stations. We will show that for each user the implementation of multiple connections with feedback information of the available transmission bandwidth is critical for supporting H.264/AVC-based scalable video coding in which the transmission packets can be further separated into multiple levels of importance. To quantify the performance, a mobile WiMAX simulation platform including both the video encoder/decoder and IEEE 802.16e MAC controls is developed.     

Seamless integration of mobile WiMAX in 3GPP networks

As the wireless industry makes its way to the next generation of mobile systems, it is important to engineer solutions that enable seamless integration of emerging 4G access technologies within the currently deployed and/or evolved 2G/3G infrastructures. In this article we address a specific case of such a seamless integration, that of mobile WiMAX in evolved 3GPP networks. In this context we investigate the architecture and the key procedures that enable this integration, and we also introduce a novel handover mechanism that enables seamless mobility between mobile WiMAX and legacy 3GPP access, such as UTRAN or GERAN. The core characteristic of this novel handover mechanism is that mobile terminals do not need to support simultaneous transmission on both WiMAX and 3GPP accesses; therefore, it mitigates the RF coexistence issues that exist otherwise and improves handover performance. In addition, we provide a brief overview of mobile WiMAX and the evolved 3GPP network technologies, and we set the appropriate background material before presenting our proposed handover mechanism. Our main conclusion is that integrating mobile WiMAX in evolved 3GPP networks is a compelling approach for providing wireless broadband services, and mobility across WiMAX and 3GPP access can become seamless and efficient with no need for mobile terminals to support simultaneous transmission on both types of access.     

WiMAX无线城域网的应用研究

在WiMAX技术和IEEE 802.16标准的基础上,研究了WiMAX无线城域网的应用;给出WiMAX无线城域网的应用领域以及具体应用设想.研究结果表明,WiMAX无线城域网的应用前景广阔.