基于地面广播的手机电视

手机电视业务可以利用蜂窝移动网络和地面/卫星数字广播来实现,其相关技术有4种:基于移动网实现技术、基于地面数字广播网实现技术、基于卫星实现技术和基于应用层实现技术。DVB-H和T-DMB是2种典型的地面数字广播电视标准,前者是DVB组织为通过地面数字广播网络向手持终端提供多媒体业务所制订的传输标准,后者是韩国推出的基于欧洲厂商开发的尤里卡147数字音频广播(Eureka-147DAB)的地面数字多媒体广播标准。目前开展手机电视业务面临着标准、频率资源、管制和终端等方面的问题,其运营模式存在移动运营商单独运营、广电单独运营和两者合作运营模式3种。手机电视是广电和通信产业融合的重要尝试,主管部门的协调和技术标准的制订将直接影响未来三网融合的进程。     

手机电视技术分析与比较

针对手机接收数字电视信号这一业务要求提出多种解决方案,并分别对欧洲数字视频广播、日本地面数字广播、卫星广播及3GPPR6版本提出的多媒体广播、组播业务进行了详细介绍与分析,着重阐述各种技术的优缺点,同时以表格形式比较了几种主要的手机电视承载技术,为网络运营选择组网技术提供参考.     

HFC Access Network Design for Switched Broadcast TV Services

The hybrid fiber coax (HFC) is a modern broadband access network, providing advanced interactive services such as Internet access, digital interactive television and cable telephony. The edge costs dominate the cost of launching new services, at the time of deployment (CapEx) as well as for maintenance (OpEx). Therefore next-generation edge devices aim at the convergence of these services and their platforms into a single multi-service infrastructure, thus sharing resources and bandwidth. The focus of this paper is on the HFC access network design for bandwidth-intensive TV services, bringing standard as well as switched broadcast technologies into play. Standard broadcast TV service deployments, offered through the digital video broadcast (DVB) platform, require low installation costs, but the bandwidth consumption increases linearly with the number of available TV channels, even for very unpopular channels. Switched broadcast TV channels, offered on the (Euro-) DOCSIS platform together with other interactive unicast services such as video on demand, are only streamed to a node on the HFC access network if they are requested locally, thus limiting bandwidth consumption for less popular channels. We present an access network design tool, based on an analytical TV traffic model, minimizing the installation cost on the edge devices and study the influence of the most important traffic and content parameters.     

DVB-H: Digital Broadcast Services to Handheld Devices

This paper gives a brief review of the new Digital Video Broadcasting-Handheld(DVB-H) standard. This is based on the earlier standard DVB-T, which is used for terrestrial digital TV broadcasting. The new extension brings features that make it possible to receive digital video broadcast type services in handheld, mobile terminals. The paper discusses the key technology elements-4K mode and in-depth interleavers, time slicing and additional forward error correction-in some detail. It also gives extensive range of performance results based on laboratory measurements and real field tests. Finally it presents viewpoints relevant for DVB-H network design and system use in general.     

IPTV--三网融合的开端

IPTV与目前的3个运营网（有线电视网、Internet和电信网）及其业务直接相关。但不同运营商对IPTV业务有不同定位。电信运营商认为IPTV业务体现于电视节目在IP网中的组织和传送形式，有线电视网络运营商认为IPTV业务是利用有线电视网来提供数字电视节目和电视节目以外的信息服务。由于IPTV业务分为广播业务和交互型业务两大类，支撑这两类业务的承载网也相应地分别采用单向广播网和双向交互网，因而在承载网层很难融合。融合工作将在业务层发生，即充分利用已经存在的两个承载网来经济、高效地发展业务。IPTV中既拥有广播型业务，又拥有组播型业务，还拥有交互型业务，将是三网融合的开端。     

Diversity Gain for DVB-H by Using Transmitter/Receiver Cyclic Delay Diversity

The objective of this paper is to investigate different diversity techniques for broadcast networks that will minimize the complexity and improve received SNR of broadcast systems. Resultant digital broadcast networks would require fewer transmitter sites and thus be more cost-effective and have less environmental impact. The techniques can be applied to DVB-T, DVB-H and DAB systems that use Orthogonal Frequency Division Multiplexing (OFDM). These are key radio broadcast network technologies, which are expected to complement emerging technologies such as WiMAX and future 4G networks for delivery of broadband content. Transmitter and receiver diversity technologies can increase the frequency and time selectivity of the resulting channel transfer function at the receiver. Diversity exploits the statistical nature of fading due to multipath and reduces the likelihood of deep fading by providing a diversity of transmission signals. Multiple signals are transmitted in such a way as to ensure that several signals reach the receiver each with uncorrelated fading. Transmit diversity is more practical than receive diversity due to the difficulty of locating two receive antennas far enough apart in a small mobile device. The schemes examined here comply with existing DVB standards and can be incorporated into existing systems without change. The diversity techniques introduced in this paper are applied to the DVB-H system. Bit error performance investigations were conducted by simulation for different DVB-H and diversity parameters     

以EPON技术促进广电网络双向改造

利用EPON技术实现有线电视双向网络改造具有明显的优势,广电网络EoC可以在一根同轴电缆上同时传输电视和双向数据信号,大大简化HFC网络的双向改造,可利用现有的HFC网络提供数字电视、互动电视和宽带服务,使广电网络具备多业务运营能力。     

数字化室分系统应用研究及未来5G室内覆盖展望

针对4G用户和VoLTE用户的快速增长以及室内移动业务的快速提升，尤其是视频、手游和网络直播等对数据业务的高要求，室内深度覆盖问题成为各大运营商建设精品网络、抢占市场，创造经济效益的重要环节。新型数字化分布系统，相比传统的DAS系统，具有高效吸收话务、灵活快速组网及快速实施的能力，能够对目标区域达到全监控、高定位、高容量、易协同及多制式覆盖的效果，是LTE网络室内深度覆盖的不二选择，亦是5G室内网络覆盖的必然趋势。     

A framework for an evolutionary path toward 4G by means of cooperation of networks

Combining networks to form a composite network for joint operations in the current business context is desirable in order to limit capital and operational expenditures, but currently requires complying with existing value chains and business models. However, commonalities between the two most popular infrastructures, mobile cellular and TV broadcast, are such that a common framework for services and QoS management can be built, without the expense of starting from scratch in the design of a universal system able to connect users for communications and entertainment. This article describes such a framework that can potentially ally mobile cellular and TV broadcast platforms as one stepping stone toward 4G and the information society.     

The small screen [TV to mobile devices]

Television is likely to start being broadcast to PDAs and mobile phones soon, with the help of shrinking screen technologies. With 3G take-up going far slower than operators hoped and the pioneering service in the UK struggling to achieve initial sales targets, stakeholders from network operators to content providers are looking at more reliable ways of generating money in a saturated handset market. Adding broadcast television functionality to mobile devices, whether they are phones or personal digital assistants, could be the answer. Getting a 100 second video clip to a million mobile subscribers at 100 kbps could occupy an entire 3G network for up to 15 minutes, while the same content could be delivered by the broadcast route using only around 0.1% of capacity. A new standard, DVB-H, will address issues like power saving. Impatient broadcasters may use existing platforms to deliver services rather than waiting for DVB-H. This raises the prospect of a digital audio standard, like DAB, being used to deliver television to a mobile phone. The article outlines some of the research being carried out.     

移动数字电视接收与DVB-H

从接收端的角度出发分析了DVB-H标准在功耗、移动性和服务质量方面的技术改进,并介绍了DVB-H最新进展,对未来移动数字电视的发展提出了自己的观点.     

Secure service convergence based on scalable media coding

In multimedia services, security and privacy issues are urgent to be solved, such as the content security and service protection. To solve these issues, some means have been proposed, such as conditional access and digital rights management. However, for the latest application scenarios in convergent networks, there is still no solution. This paper focuses on the convergent multimedia broadcasting applications: the multimedia content, e.g., TV program, is encoded and packaged by the content provider, and is then transmitted to users through different communication networks, e.g., 3G network, DVB-H, ADSL, etc. Thus, the same multimedia content will be used for various services, i.e., mobile TV, Internet TV and home TV. Since different network channel support different bandwidths, the multimedia content should be transcoded before being transmitted through the networks. To protect the content and service in this application, we propose the content and service protection methods. In content protection, the content provider encrypts the scalable multimedia content with the manner denoted by Encryption Flag. The content distributor has no decryption keys, but can transcode the scalable content with the manner denoted by Layer Flag, and transmit the transcoded content to users. In service protection, the content provider combines the encryption key, Encryption Flag and the user right information, and transmits them, independent from the encrypted content, to certified users. At user side, the content is decrypted with the received key according to the Encryption Flag and Layer Flag. Thus, the content provider needs only to encrypt the content once, which can be transcoded by the content distributor in a secure manner and used for various networks. Additionally, the user rights need not to be changed when the service network is changed. Totally, the proposed scheme is secure and efficient for service convergence.     

实现手机电视的技术方式

DVB-H手机电视技术从传统的数字电视技术演进而来并广泛应用于3G移动通信中。回顾数字电视技术的发展历史,比较基于手机的流媒体业务、MBMS、DVB-H、MediaFLO和DVB-S不同调制方式的数字电视技术的优缺点,并分析5种传输系统在不同网络环境中的运行性能。     

国际数字红利发展移动宽带业务的经济价值分析

广播电视经过模数转换后带来数字红利频段。分析了数字红利频段的传播特性和发射功率覆盖效率。使用700 MHz建设移动通信网络,在相同覆盖条件下,建设成本约为2.6 GHz频段的1/8。通过研究国外数字红利频段的规划,对比数字红利频段与其他频段的拍卖和收益情况,数字红利频段的拍卖价格为2.6 GHz等高频的30~40倍,带来的巨大经济收益也是广播电视业务的5~10倍。将数字红利频段应用于宽带移动业务将产生的巨大社会影响和经济收益,对我国数字红利频段的规划和使用起到参考作用。     

构建面向综合业务的有线电视网

有线电视运营商以互联网业务需求采用的CableModem技术作为数据回传手段，已不能满足宽带数据应用和内容对带宽的需求，没有高性能的双向网络是一直制约有线电视网的信息化发展进程的要素。随着数字电视的发展与推广，有线电视网的数字化和信息化再一次得到关注，新的业务、技术和设备不断涌现，有线电视网发展面临着新的机遇，如何构建面向综合业务的有线电视网将是实现重大突破的基础与方向。从综合业务需求、网络演进、双向接入技术发展以及网络架构设计的角度出发，全面分析了有线电视网的发展趋势，提出了基于有线电视网现状的发展演进的网络架构，这对有线电视运营商的业务发展和网络长远规划具有很强的实践指导意义。     

数字电视整体转换后的创新

有线电视数字化整体转换已进入全面推广阶段。整体转换后，广电网络运营商如何扩大业务范围，开发多种增值业务，使用户真正体验到数字化的好处并乐意消费，从而提高经营效益，这一切都离不开创新，必须及早进行业务、营销、服务、运营等方面的创新。     

A Flexible QoS-aware Service Gateway for Heterogeneous Wireless Networks

The integration of different types of wireless access networks, or heterogeneous wireless networks (HWN), is emerging. This article investigates in particular how a combination of UMTS (Universal Mobile Telecommunications System) cellular networks, wireless LAN ad hoc networks, and DVB-H (digital video broadcasting - handheld) broadcasting networks, called UWD networks for short, is constructed and managed to provide users with QoS-aware services. Given the complexity of the UWD networks, a novel policy-based service gateway is proposed. As a software framework sitting over and communicating with the UWD network, this UWD service gateway makes network management decision by reasoning over a set of predefined policies that describe the behaviors of the UWD network. Network variables such as bandwidth, delay, and mobility in policies are fuzzified using fuzzy control theory to make the service gateway (as well as the whole UWD network) more flexible and robust. Both the prototype implementation and the evaluation results indicate the feasibility and effectiveness of the system     

多媒体移动接收与DVB-H的发展

DVB-H是数字视频广播(DVB)组织为通过地面数字广播网络向便携/手持终端提供移动多媒体业务所制订的最新标准.本文分析并介绍了3G、WLAN和DVB-H在多媒体移动接收领域各自的技术特点和最新进展,对未来多媒体移动接收领域的发展提出了自己的观点.     

江阴电视台数字播出监控系统

江阴电视台全数字硬盘播出系统在没有设计完整的智能监控、监测系统的前提下通过不断摸索实践,在不增加经济成本的前提下利用现有设备,逐步形成比较完善的监控、监测系统,为电视的安全优质播出提供了保障,对中小型电视台来说实用可行,性价比高。     

Alternative technologies and delivery systems for broadband ISDNaccess

Switched on-demand video is expected to become a major consumer of bandwidth. Two-way video offers televisting, tele-education, and telecommuting services, which together could represent a further substantial bandwidth demand. High-speed data services to provide the fiber distributed data interface (FDDI) between locations, or even operate a computer-aided design (CAD) terminal remotely from its local area network (LAN), are likely new applications for broadband integrated services digital networks (B-ISDN). The video quality evolution and digital modulation techniques that are making broadband digital delivery of TV signals possible are reviewed. Cable TV B-ISDN delivery, short twisted pair B-ISDN delivery, and TV broadcast digital delivery are discussed