数字视频广播卫星宽带IP接入系统的应用与发展

介绍一种利用数字视频广播(DVB)／MPEG-2技术与TCP、UDP／IP协议紧密结合的卫星宽带接入系统,分析了该接入系统传输的宽带多媒体信号数据格式,对卫星宽带IP通信服务未来的前景作了展望。     

一种新颖的针对单小区点对多点e MBMS业务传输技术(英文)

多媒体广播多播业务(MBMS)是3GPP R6版本中定义的一种典型的广播、多播业务。随着技术的演进,在LTE系统中提出了增强的MBMS,即e MBMS业务。针对e MBMS业务,提出了一种有效的技术解决方案。该方案可看作下行发射分集、基于DoA的波束赋形与HARQ技术的结合。同     

高集成度多波段外辐射源雷达接收机的设计与实验

针对现阶段外辐射源雷达多波段软件无线电(SDR)系统集成度低,体积大和硬件结构复杂的不足,设计了一种高集成度、多波段、小型化、低成本的外辐射源雷达SDR接收机系统。系统由高集成度的AD9361射频芯片、现场可编程门阵列(FPGA)和USB 3.0传输模块组成,目的是利用调频(FM)广播、中国移动多媒体广播(CMMB)和数字电视地面多媒体广播(DTMB)第三方机会照射源实现对目标的探测。实测数据结果表明,该系统能够对多波段信号进行正确的采集,并将数据传输到上位机。外场实验验证了该系统的可靠性以及良好的目标探测性能。     

多媒体广播业务在TD-SCDMA系统中的实现

多媒体广播主要是指移动终端用户在具有操作系统和视频功能的智能移动终端上以频道或信道的形式接收广播形式的数字音视频内容（例如电视等）。多媒体广播有两种主要技术种类：一种是广电系统的大区制的地面广播手机电视标准，另一种是基于移动通信系统蜂窝网的MBMS（多媒体广播和组播技术）标准。本文主要讨论在TD-SCDMA网络中，如何实现MBMS技术来承载多媒体广播业务。     

TD-SCDMA系统中多媒体广播业务的实现

多媒体业务是目前被业界看好的一个非常有潜力的应用。多媒体广播的一种主要技术种类是基于移动通信系统蜂窝网的多媒体广播和组播技术（MBMS）标准。主要介绍了在TD-SCDMA移动通信系统中如何实现多媒体广播业务,并介绍了相关技术的标准进展、网络架构以及具体的技术方案。     

数字多媒体广播技术现状及前景

数字多媒体广播（DMB）是从数字音频广播（DAB）基础上发展起来的一种新型广播技术。数字音频广播是在调幅AM和调频FM之后的第三代广播技术。通过对数字多媒体技术的介绍较全面地阐述了其技术系统、功能、现状及发展前景。     

数字广播电视技术与卫星应用(四)

第四讲卫星多媒体广播技术随着1992年世界无线电管理大会(WARC)对广播卫星业务(声音)波段进行了重新分配,面向车载高速移动终端、手持便携终端和固定接收终端的数字多媒体广播的需求与日俱增。到目前为止,已经有几个基于本国覆盖或者跨国覆盖的数字多媒体直播卫星系统开始运行。为了提供必要的技术和运行方面的参考信息,推动数字卫星多媒体直播系统的发展,指导为制定统一技术标准的实践活动,国际电联参考了ITU-R BS.774建议书和ITU-R BO.789建议书的有关细节,推出了数字多媒体直播系统技术标准(ITU-R BO.1130-4建议书)。这个标准中推荐了在1.4GHz～2.7GHz广播卫星业务频段上开展面向车载、便携和固定接收终端的五大数字卫星多媒体直播系统。这些系统包括：System A,System B,System D_S,System D_H和System E (System C专供地面多媒体广播)。下面简介其     

基于MBMS的手机电视技术

多媒体广播组播业务(MBMS)是3GPP Release 6版本中引入的一项重大功能,目的在于节省系统资源,为用户提供广播或者组播的分组数据业务.作为一种具体的MBMS应用,手机电视技术在3G业务中占有重要的地位.文中介绍了多媒体广播和组播技术(MBMS),包括MBMS的网络结构、业务流程以及基于TD-SCDMA的MBMS系统架构,对LTE中的E-MBMS技术进行了初步研究,并从逻辑结构、业务模式和信道结构等方面简单分析了从MBMS到E-MBMS的演进.     

支持下载业务的移动多媒体广播业务方案分析

分析了实现移动多媒体广播的几种方案,并提出一种基于混合网络、同时支持下载业务的移动多媒体广播业务实现方案。本方案通过移动网络实现业务管理,采用分层密钥管理体系提高系统安全性,同时引入DRM(digital right management)模块,支持节目片段下载的业务。该方案对于实现移动多媒体广播业务的运营管理以及与下载业务的融合有着重要的意义和应用价值。     

高新技术研究与开发奖一等奖移动多媒体广播(CMMB)系统设备测试方法及检测系统研究

随着数字广播电视技术的迅猛发展,通过广播电视网开展移动多媒体广播(CMMB}新业务,已经成为占领新的宣传阵地、丰富人民群众的文化生活的重要手段之一.为了推动我国移动多媒体广播(CMMB)事业的快速发展,根据国家广电总局的统一部署,受国家广电总局科技司委托,中广卫星移动广播有限公司、广播科学研究院、广播电视规划院以及中国国际电视总公司共同承担了<移动多媒体广播(CMMB)应用歪统技术研究与实现>项目.其中,广播电视规划院承担了子课题<移动多媒体广播(CMMB)系统设备测试方法及检测系统研究>的工作.     

CMMB单频网多径模型研究

中国移动多媒体广播(CMMB)是我国自主研发的一套移动多媒体广播网络系统。在现有公式的基础上进行优化,给出一种更好的CMMB单频网两径和三径信道模型,两径公式的相关系数基本大于0.96,三径公式的相关系数基本大于0.92。     

Wireless ATM networks: technology status and future directions

The concept of “wireless ATM” (WATM), first proposed in 1992, is now being actively considered as a potential framework for new-generation wireless communication networks capable of supporting integrated, quality-of service (QoS) based multimedia services. In this review paper, we outline the technological rationale for wireless ATM, present a system-level architecture, and discuss key design issues for both mobile ATM switching infrastructure and radio access subsystems. The WATM radio access layer issues covered in this paper include: spectrum allocation; spectrum etiquette; modem technology; and medium access/data link control (MAC/DLC) protocols. Mobile ATM aspects such as ATM signaling extensions for handoff control, location management, and mobile QoS control are discussed. A summary of current wireless/mobile ATM technology development and standardization status is given, including an outline of our WATMnet prototype. The paper concludes with a discussion of future directions for wireless ATM technology such as Internet protocol (IP) integration and mobile multimedia terminals/applications     

A layered protocol architecture for multimedia wireless‐PCS networks

Coupled with the growing interest in the Universal Mobile Telecommunication System (UMTS) as a standard for future mobile communications, the need for a set of functions to effectively support multimedia teleservices in such an environment is also increasing. Starting from the idea that multimedia means the integrated manipulation of different information and hence the independent handling of separate information is not satisfactory, an enhanced protocol architecture for the support of multimedia teleservices in Wireless Personal Communication Systems based on UMTS is proposed. It involves Physical, MAC, Data Link, and Network layers. A Synchronisation Sub-Layer is introduced on the MAC level with the main aim of assuring a rough multimedia inter-stream synchronisation over the air interface, which is a first step prior to a fine end-to-end synchronisation performed by higher layers. Proposed functions, their basic algorithms, their location in the protocol stack, as well as the signalling exchange among modules implementing them, on network and user sides, are described in detail in the paper. The resulting architecture well fits the demanding nature of multimedia services and can be easily interfaced with the wired backbone of the system. This revised version was published online in July 2006 with corrections to the Cover Date.     

网络融合下的鉴权技术研究

为提供整体鉴权管理机制以实现固网与移动网络的融合,在对现有通信网络及IMS的安全鉴权进行研究的基础上,提出以EAP-AKA协议加上SIM卡的鉴权机制和只使用SIM卡的用户识别功能两种方案,形成融合网络的整体鉴权。最后对融合网络的未来鉴权机制做了探讨。     

嵌入式实时操作系统pSOS在多媒体通信终端中的应用

在多媒体通信终端的基本实现方案中,通常有基于PC平台的终端和基于媒体处理器的独立机型终端两种。在后一种方案中,硬件系统的资源管理和应用软件的开发都是基于嵌入式实时操作系统来实现的。Philips公司的TriMedia媒体处理器,介绍嵌入式实时操作系统pSOS在H．324多媒体通信终端中的应用。     

Definition of a new service class,artPS for video services over WiBro/Mobile WiMAX systems

Increased development in the area of networking has coincided with an increased demand for multimedia services via high data rates. Nevertheless, adaptation of the current volume of multimedia data to capacity-limited commercial wireless networks has not kept pace. The Wireless Broadband (WiBro)/Mobile Worldwide Interoperability for Microwave Access (WiMAX) system, which is expected to be one of the platforms for 4G wireless communications, entertains several kinds of service classes with respect to the characteristics of services. However, no effective techniques have been specified to deal with the quality degradation that occurs in conjunction with either dynamic channel fluctuation or throughput dropping at the cell edge over highly error-prone channel environments. In this paper, we define a new service class, advanced real-time Polling Service (artPS), that adapts to the channel variation by introducing layered coding like Scalable Video Coding. Utilizing this artPS class, the proposed system very efficiently achieves higher Quality of Service, while maintaining backward compatibility with the conventional system and attaining the multiplexing gain of layered data.     

移动多媒体通信关键技术研究

移动多媒体通信是未来通信的发展趋势。通过探讨移动多媒体通信数据量大、实时性要求高、无线信遗缺乏QoS保证等特点，介绍了和移动多媒体通信密切相关的几种技术：网络技术；视频编码技术、流媒体技术。     

3rdgeneration mobile systems umts/imt-2000

When International Telecommunication Union (itu) identified in 1992 new frequency bands for third generation mobile systems, few people were really convinced that there was a need for such systems because the first second generation systems (like gsm in Europe) were recently launched and nobody could imagine at that time that 8 years later penetrations rates for voice will exceed 50% in several countries. The development of multimedia services in fixed networks was the key factor to trigger standardisation activities in different organisations (ITU, etsi ) involved in mobile systems. But rapidly, the globalisation of this activity led to the birth of different standardisation forums with the objective to develop specifications for multimedia mobile systems called imt 2000 (International Mobile Telecommunication 2000). One of this system is UMTS (Universal Mobile Telecommunication System) which is supported by different Japanese and European companies; the first commercial launch of such a network is foreseen in October 2001 in Japan and at the beginning of 2002 in Europe, umts will offer higher data rates (up to 384 kbit/s in a first phase) and better spectral efficiency than existing mobile systems;     

GRACE-1: cross-layer adaptation for multimedia quality and battery energy

Mobile devices primarily processing multimedia data need to support multimedia quality with limited battery energy. To address this challenging problem, researchers have introduced adaptation into multiple system layers, ranging from hardware to applications. Given these adaptive layers, a new challenge is how to coordinate them to fully exploit the adaptation benefits. This paper presents a novel cross-layer adaptation framework, called GRACE-1, that coordinates the adaptation of the CPU hardware, OS scheduling, and multimedia quality based on users' preferences. To balance the benefits and overhead of cross-layer adaptation, GRACE-1 takes a hierarchical approach: It globally adapts all three layers to large system changes, such as application entry or exit, and internally adapts individual layers to small changes in the processed multimedia data. We have implemented GRACE-1 on an HIP laptop with the adaptive Athlon CPU, Linux-based OS, and video codecs. Our experimental results show that, compared to schemes that adapt only some layers or adapt only to large changes, GRACE-1 reduces the laptop's energy consumption up to 31.4 percent while providing better or the same video quality.     

Quality biased multimedia data retrieval in microblogs

With the rapid development of social media platforms, huge amount of user generated contents (UGC) are generated ceaselessly. In recent years, content based microblog retrieval has attracted extensive research attention. Effective microblog retrieval services complex analysis of short text and multimedia contents. In this paper, we present a quality biased multimedia microblog retrieval framework. First, we develop an anchor graph based multiview embedding framework which maps the multimedia content features into a unified latent space. Then, the content matching scores of testing microblogs related to the query are obtained by a Markov random field. Further, we employ an quality model to incorporate both microblog quality and content matching. As compared with the state-of-art methods, experimental results demonstrate the effectiveness of the proposed approach.