Modeling and evaluating IPTV applications in WiMAX networks

Internet Protocol-based Television (IPTV) is a digital television service which delivers television content via an IP network. The rapid growth of wireless network technology in recent years has changed, the way people access the Internet. Adding mobility to IPTV can create a truly compelling ubiquitous service which spans different network domains and varied IP-enabled terminals and devices, such as set-top boxes, PCs and cell phones. However, extending IPTV service to wireless networks requires overcoming bandwidth bottlenecks and high packet loss rates. Following the IEEE 802.16 standard, worldwide interoperability for microwave access (WiMAX) features high data rates and large service coverage, offering a wireless broadband solution for IPTV services. While previous research has focused on creating a broadband IPTV service few studies have practically evaluated IPTV applications in a wireless broadband network environment. In this paper, we model and evaluate a common constant bit rate (CBR)¹ based IPTV application and an IPTV live streaming (PPStreaming)² application while retrieving IPTV content via a WiMAX network. We also use the NS2 simulation tool to evaluate the performance of these two IPTV applications. The evaluation metrics include latency, packet loss, data rate and throughput statistics when the two IPTV applications are run in the WiMAX network. ¹The simplest IPTV solution is to convey video content by CBR. IPTV operators and content delivery networks relay CBR streaming content to control the demand for network capacity. Broadcasters prefer CBR video as it conserves bandwidth resources, but CBR delivery can degrade video quality result in higher overall demand on network capacity. ²PPStreaming (also referred to as P2P streaming Internet TV) is a network for live media streaming. In principle it’s similar to BitTorrent (BT) in that it provides stable and smooth broadcast of TV programs to broadband users. Unlike traditional streaming media, PPStreaming adopts P2P-streaming technology and supports full-scale visits with tens of thousands of simultaneous users. Its client software can be used in the browser or as a standalone executable.     

Secure communication in IPTV broadcasting

In internet protocol television (IPTV) broadcasting, service providers charge subscribing fee by scrambling the program with conditional access system (CAS) using control words (CWs). A smart card is used to decrypt the CWs and transfer them back to set-top box (STB) to descramble the scrambled program. Secure communication between STB and the smart card is closely related with the benefit of service providers and the legal rights of users. In addition, secure key exchange with mutual authentication in the communication between STB and the smart card is an essential part of secure communication that will significantly improve the security of the system. To provide secure communication with mutual authentication in IPTV broadcasting, there are several schemes. The schemes proposed a secure and efficient method for the communication between STB and the smart card. Unfortunately, the schemes still have some security flaws. In this paper, we review that the previous schemes are vulnerable to several attacks. Further, we recommend some modifications to the schemes to correct these security flaws and present a formal analysis about our improved protocol using a logic based formal method.     

A hybrid user authentication protocol for mobile IPTV service

IPTV, a technological convergence that combines communication and broadcasting technologies, delivers customized, interactive TV content and other multimedia information over wired and wireless connections. Providing secure access to IPTV services calls for authentication, without proper and secure authentication mechanisms, an individual impersonating a subscriber could steal a service. This paper proposes a new authentication protocol to authenticate IPTV users. The authors based the proposed protocol, a hybrid authentication protocol providing lightweight, personalized user authentication, on RFID (radio-frequency identification) and USIM (Universal Subscriber Identity Module) technologies. In the proposed protocol, USIM performs highly personalized authentication, and the authenticated subscriber’s RFID tags can have a temporary authority to execute authentication. These RFID tags become Agent Tags authorized to authenticate subscribers. Agent Tags identify and authenticate themselves to RFID readers in the set-top box, thus, simplifying the authentication process.     

基于嵌入式Linux的IPTV机顶盒浏览器的研究与实现

随着互联网技术的不断发展和应用的不断普及,网络电视已悄然崛起,并有代替现有广播电视的趋势。本文详细分析网络电视以及IPTV机顶盒浏览器技术,提出基于Webkit的嵌入式浏览器,并详细叙述其工作流程及设计步骤。实验结果表明,该嵌入式浏览器支持多窗口打开页面链接,支持中文显示,图片渲染速度快;同时,Webkit提供历史页面的缓存,支持后退、前进以及历史显示等功能。     

A robust NFC-based personalized IPTV service system

Internet Protocol Television (IPTV) is becoming a platform that changes the way we obtain information and entertainment, and offers interactive features and personalized services. Although IPTV service providers can perform TV viewer identification and authentication through a unique hardware identifier in the form of a set-top box (STB), it is based on STB-level identification which leads to the situation where all members of a subscriber family get the same level of access to services. This indicates that existing identification schemes are inconsistent with IPTV’s main intent, namely, providing personalized services. Smartphones with NFC (Near Field Communication) capabilities have grown to become very popular over the years. In this study, we present a novel personalized IPTV service system in which NFC-based identification with HCE (Host Card Emulation) is adopted. The experiments and analyses show that the proposed system can meet the system requirements and provide great usability, deployability and service scalability for personalized IPTV services.     

智能电视远程传感器控制的实现方法

主要介绍了一种在电视上加载虚拟传感器设备驱动的方法, 将具有传感器功能的手机、PAD等智能终端作为电视传感器输入终端, 在智能电视上实现利用传感器控制应用和游戏的解决方案. 具体实现方法为在智能电视上加载各种传感器如重力加速度(G-sensors)、线性加速度、陀螺仪等的虚拟设备驱动, 并提供上层传感器数据注入方法和应用层传感器数据获取通用接口; 智能传感器输入终端通过wifi与智能电视建立网络连接, 获取智能终端的传感器实际数据, 并将数据发送到电视端; 电视端接收到数据并注入到指定传感器设备, 最终由系统上报提供到应用层, 使得各类普通的传感器类应用和游戏在电视上展现. 可解决现在智能电视上应用和游戏单一的局面, 实现应用和游戏控制与画面相分开, 以获得更好的视觉效果并很好的与他人分享.     

IPTV service based on a content-zapping paradigm

Internet protocol television (IPTV) generically designates a real-time distribution service for multimedia contents over an IP network, such as the Internet. There are many advantages of IPTV deployment over current digital or air broadcast TV signals: integration, the use of the switched internet protocol (IP), the possibility to build home networks that can be used to share multimedia contents over different devices, the easy implementation of video on demand services and the usage of better compression and encryption standards. In order to implement this kind of service, it is extremely useful to have a system that can efficiently classify multimedia contents and users and distribute them in a customized way. This paper proposes a novel IPTV service for the distribution of personalized multimedia contents over IP networks based on the concept of content-zapping, in contrast to traditional channel-zapping: each client system receives a multimedia streaming that is automatically composed by the system based on the user preferences and the user will only interact with the system by requesting a content change or marking a content as favorite. The paper will describe the general functionality of the service and will present the detailed architecture of the IPTV server, the key component of the service infrastructure. The server must maintain a list of media contents residing in other systems and must keep a dynamic classification of the multimedia contents that are stored in its database. This classification is built and gradually refined based on the interactions between clients and multimedia contents. Special attention is given in the paper to the classification model, describing the general ideas that are used to automatically suggest multimedia contents to a specific user (that is characterized by his complete profile). A specific content may be suggested to the user based on the knowledge of the user profile and/or based on specific and dynamic information, such as the user position, the local temperature, date and time. The availability of this information obviously depends on the specific user device that is being used. The proposed system allows any client device to connect, allowing a high level of interoperability. It is also possible to use all the device capabilities and sensors, like Global Positioning System (GPS), accelerometers, light sensors, noise sensors, etc., thus creating a context environment that helps classify each user profile. These context-awareness mechanisms applied to mobile devices with wireless network (802.11b/g/n, WiMAX, GSM, UMTS, etc.) capabilities allow a better user experience and more accurate multimedia suggestions, due to the deep knowledge about the user device, network and environment. The system also allows the users to suggest contents to other users in the same “group of friends”. Several performance tests were already conducted and the results obtained show that the proposed system is very stable and fast, even for high increases on the number of users.     

基于Linux的机顶盒的现状与展望

随着数字电视的快速发展，机顶盒越来越普及；随着时间的推移，Linux操作系统越来越被用户认可。基于Linux的机顶盒，就是这一趋势的产物。当前，大部分机顶盒都是基于Linux开发的。未来，这一趋势还会更明显。     

基于TCP的支持多格式实时编码的流媒体直播系统设计与实现

随着多媒体技术的发展和宽带网络的普及,IPTV系统在国内已经得到越来越广泛的应用,直播系统作为其中的一个子系统虽然满足用户的需求可以进行时移操作,然后面向的基本都是机顶盒用户群,对于大部分PC用户来说,能够支持时移的直播系统几乎没有。基于DirectShow和Socket技术,建立了一种流媒体音视频实时编码及网络传输系统,并且可以支持时移功能。     

同煤集团有线数字电视机顶盒部署分析

大同煤矿集团有线数字电视建设共约覆盖18．2万户,为使机项盒能够满足有线数字电视系统的要求,特深入研究数字机顶盒原理以及选型要求,保障使用效果。机顶盒的全称叫做“数字电视机顶盒”,英文缩写“STB”（Set—TopBox）。它是一种将数字电视信号转换成模拟信号的变换设备,它把经过数字化压缩的图像和声音信号解码还原成模拟信号送入普通的电视机。     

基于最少器件电路替代智能卡接口芯片的设计

简述了数字电视系统中智能卡的工作原理,介绍了智能卡接口芯片TDA8024的功能,由此设计了一款电路替代TDA8024,并分析了测试结果。结果表明,此电路能够很好的替代TDA8024实现智能卡与机顶盒的通信,符合ISO7816标准,有效地降低了成本。目前此电路已经应用于数字机顶盒产品中。     

Paper remote: an augmented television guide and remote control

The television (TV) is one of the most common entertainment devices in homes. Searching and finding TV programs is a common task and using TV guides is one way of performing this. This paper presents three studies that are focused on examining audiences’ TV habits and TV guide usage, evaluating a new concept based on linking paper and pen with TV technology, and studying the audiences’ attitudes toward and anticipated interest in the future guide. The results of our first study emphasize the value of using paper based TV guides and also identify the deficiencies. We also found indications that the advantages and disadvantages of paper-based TV guides are related to the physical properties of paper. Thus, we suggest a solution that uses digital pen and paper technology to offer a new interaction method for TV. A research system “Paper Remote”, is developed and used in the two subsequent studies. Viewers tick designated areas on the paper-based guide to perform actions such as channel switching. However, this solution is not a substitute for the remote control device. We argue that these user studies on linking digital paper to the TV for everyday information navigation illuminate the possibilities of providing innovative solutions also for home information systems also.     

机卡分离中基于身份的认证及密钥协商协议

为增强数字电视条件接收系统的安全性,用户端宜采用“机卡分离”的方法。其中,设计既安全又切实可行的机卡认证及密钥协商协议是一个重要环节。该文根据机卡分离环境的需求,设计了一个基于身份的双向认证及密钥协商协议。该协议可以抵抗中间人攻击、交错攻击与反射攻击。并且与基于证书的协议相比,无需可信第三方的介入,协议双方具有较少的通信量,在智能卡端也具有理想的计算量和较小的存储空间。     

Puzzle: A mobile application development environment using a jigsaw metaphor

ObjectiveCreate a visual mobile end user development framework, named Puzzle, which allows end users without IT background to create, modify and execute applications, and provides support for interaction with smart things, phone functions and web services.MethodsDesign of an intuitive visual metaphor and associated interaction techniques for supporting end user development in mobile devices with iterative empirical validation.ResultsOur results show that the jigsaw is an intuitive metaphor for development in a mobile environment and our interaction techniques required a limited cognitive effort to use and learn the framework. Integration of different modalities and usage of smart things was relevant for users.ConclusionPuzzle has addressed the main objective. The framework further contributes to the research on mobile end user development in order to create an incentive for users to go beyond consuming content and applications to start creating their own applications.PracticeUsage of a mobile end user development environment has the potential to create a shift from the conventional few-to-many distribution model of software to a many-to-many distribution model. Users will be able to create applications that fit their requirements and share their achievements with peers.ImplicationsThis study has indicated that the Puzzle visual environment has the potential to enable users to easily create applications and stimulate exploration of innovative scenarios through smartphones.     

A natural language model for managing TV-Anytime information in mobile environments

The TV-Anytime standard describes the structures of categories of digital TV program metadata, as well as user profile metadata for TV programs. We describe a natural language (NL) model for the users to interact with the TV-Anytime metadata and preview TV programs from their mobile devices. The language utilises completely the TV-Anytime metadata specifications (upper ontologies), as well as domain-specific ontologies. The interaction model does not use clarification dialogues, but it uses the user profiles as well as TV-Anytime metadata information and ontologies to rank the possible responses in case of ambiguities. We describe implementations of the model that run on a PDA and on a mobile phone, and manage the metadata on a remote TV-Anytime-compatible TV set. We present user evaluations of the approach. Finally, we propose a generalised implementation framework that can be used to easily provide NL interfaces for mobile devices for different applications and ontologies.     

A novel prebuffering scheme for IPTV service

The Internet Protocol TeleVision (IPTV) network utilizes the broadband IP network to provide users the TV service. Due to the limited bandwidth of the IP network, IPTV does not broadcast the content of all channels to its users. The channel zapping time (i.e., the delay between the time when the user switches to a new TV channel and the time when the content of the new TV channel is received by the user) and content miss (i.e., the content of the new TV channel arrives after the user switches to another TV channel so that the user did not watch the content of the new TV channel) significantly affect the QoS of IPTV service. This paper proposes Dynamic Prebuffering Scheme (DPS) that dynamically prebuffers the content of TV channels in the Home Gateways (HGs) based on the user’s behavior to reduce the channel zapping time and the content miss probability. A prebuffer timer is implemented in DPS to reduce the bandwidth consumption. Both the analytic model and simulation experiments are developed to investigate the performance of DPS. The simulation results show that the performance enhancements are bounded by the setup of the number of prebuffering channels and the prebuffer timer. Based on the performance study, the IPTV operators can properly set the number of prebuffered channels and the prebuffer timer to obtain good performance. Our study indicates that DPS can significantly reduce the channel zapping time and the content miss probability by slightly increasing bandwidth consumption.     

Customizing User Interaction in Smart Phones

Emerging input modalities could facilitate more efficient user interactions with mobile devices. An end-user customization tool based on user-defined context-action rules lets users specify personal, multimodal interaction with smart phones and external appliances. The tool's input modalities include sensor-based, user-trainable free-form gestures; pointing with radio frequency tags; and implicit inputs based on such things as sensors, the Bluetooth environment, and phone platform events. The tool enables user-defined functionality through a blackboard-based context framework enhanced to manage the rule-based application control. Test results on a prototype implemented on a smart phone with real context sources show that rule-based customization helps end users efficiently customize their smart phones and use novel input modalities.     

基于智能手机的远程家电控制及安防监测系统的设计

设计了基于智能手机和GPRS网络的远程家电控制和安防监测系统.智能手机采用开放式操作系统,第三方可根据操作系统提供的API为其开发各种扩展应用.利用智能手机这一特性,开发用于系统的人机接口,方便了用户的操作.介绍了系统的结构和功能,详细阐述了智能手机监控软件的开发过程.     

SeeNSearch: A context directed search facilitator for home entertainment devices

The Internet has become an extremely popular source of entertainment and information. But, despite its growing popularity, most websites today are accessed by keyword search via web browsers, making it difficult for home consumers to locate Internet content of interest on their TVs or other devices that lack keyboards. In this paper, we present assistive technologies, enabling users to easily locate Internet content related to the TV program they are watching. Access is enabled via an intuitive user interface on the TV screen or by using a secondary personal device, and thus avoiding disrupting the viewing experience of the other TV users.     

非Root权限下ITV Traceroute和抓包功能研究

 为了提高ITV用户侧的感知质量,在ITV发生故障时用户可以自主地进行一系列的诊断,包括Traceroute、抓包测试等,但是要实现Traceroute和抓包功能就必须获取机顶盒的Root权限,而厂家一般不会开放机顶盒的Root权限,正常情况下用户也不能通过这2种测试方案对ITV故障进行测试。为此本文提出一种方法可在Root权限未开放的情况下,应用层与底层通过Socket通信,将Traceroute和Tcpdump命令编译成二进制文件在机顶盒运行。通过厂家增加相对应的服务项对固件进行升级,从而在非Root权限下实现Traceroute和抓包功能,提高用户侧的感知质量,减少用户投诉率。