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.     

An Effective IPTV Channel Control Algorithm Considering Channel Zapping Time and Network Utilization

This paper presents a simple but effective IPTV channel control algorithm that keeps channel zapping time in the tolerable range with high network utilization. The proposed algorithm controls channel zapping time by adjusting the number of broadcasting channels that are located close to users over IP networks and the number of additional I-frames inserted into each channel, based on the user's channel preference information. Finally, experimental results are provided to show the performance of the proposed algorithm.     

Reducing channel change delay in IPTV by predictive pre-joining of TV channels

One of the major concerns of IPTV network deployment is channel change delay (also known as zapping delay). This delay can add up to 2 s or more, and its main culprits are synchronisation and buffering of the media streams. Proving the importance of the problem is the already significant amount of literature addressing it. We start this paper with a survey of techniques proposed to reduce IPTV channel change delay.Then, by analysing an extensive dataset from an operational IPTV provider - comprising 255 thousand users, 150 TV channels, and covering a 6-month period - we have observed that most channel switching events are relatively predictable: users very frequently switch linearly, up or down to the next TV channel. This fact motivated us to use this dataset to analyse in detail a specific type of solutions to this problem, namely, predictive pre-joining of TV channels. In these schemes each set top box (STB) simultaneously joins additional multicast groups (TV channels) along with the one that is requested by the user. If the user switches to any of these channels the switching latency is virtually eliminated, not affecting therefore user's experience.We start by evaluating a simple scheme, where the neighbouring channels (i.e., channels adjacent to the requested one) are pre-joined by the STB during zapping periods. Notwithstanding the simplicity of this scheme, trace-driven simulations show that the zapping delay can be virtually eliminated for a significant percentage of channel switching requests. For example, when sending the previous and the next channel concurrently with the requested one, for only 1 min after a zapping event, switching delay is eliminated for close to half of all channel switching requests. Importantly, this result is achieved with a negligible increase of bandwidth utilisation in the access link. Other more complex schemes where user behaviour is tracked were also evaluated, but the improvement over the simple scheme was insignificant.     

An Effective Channel Control Algorithm for Integrated IPTV Services Over DOCSIS CATV Networks

In this paper, we present an effective IPTV channel control algorithm that guarantees a seamless channel change and provides a fast data communication service simultaneously via controlling the usage levels of uplink and downlink resources over DOCSIS CATV networks. The proposed algorithm treats the number of adjacent channels and the assigned grant interval as control variables to reduce the network delay part of channel zapping time and improve the quality-of-service of the uplink and downlink. Finally, the experimental results are provided to show the performance of the proposed algorithm.     

一种改进的IPTV快速频道切换技术方案

频道切换时间是IPTV业务服务质量的重要指标之一,快速的频道切换能显著提升IPTV业务的用户体验.本文提出一种改进的基于视频典型帧提取的快速频道切换技术方案,该方案可用于改善IPTV用户对于频道切换速度的体验时间.     

Improving IPTV Forwarding Mechanism in IEEE 802.16j MMR Networks Based on Aggregation

Internet protocol television (IPTV) service depends on the network quality of service (QoS) and bandwidth of the broadband service provider. IEEE 802.16j mobile multihop relay Worldwide Interoperability for Microwave Access networks have the opportunity to offer high bandwidth capacity by introducing relay stations. However, to actually satisfy QoS requirements for offering IPTV services (HDTV, SDTV, Web TV, and mobile TV) for heterogeneous users' requests, providers must use a video server for each IPTV service type, which increases the network load, especially bandwidth consumption and forwarding time. In this paper, we present a solution for forwarding IPTV video streaming to diverse subscribers via an 802.16j broadband wireless access network. In particular, we propose a new multicast tree construction and aggregation mechanism based on the unique property of prime numbers. Performance evaluation results show that the proposed scheme reduces both bandwidth consumption and forwarding time.     

降低IPTV频道切换时间的方式研究

从分析IPTV频道切换时间的制约因素出发,研究了IPTV的网络结构和使用协议,并提出了通过对接入网结构的改造:WDM-PON混合组网方式,IGMP协议的修改,以及相邻组播组加入/离开方式,达到对IPTV频道切换时间的改进.     

云社交电视的用户视频质量体验

近年来,多屏云社交电视将社交体验引入了传统的电视领域中.观看同一内容社交电视的观众虽然来自不同的地方,但是仍然可以通过文本、图像、音频和视频来进行互动,这就在传统体验上增强了社会属性.笔者将社交电视用户体验分为3个要素(用户延迟、视频质量体验和资源利用率),并且提供一个通用算法来提高用户体验.具体来说就是提出了一个基于云计算的最佳播放速率分配方案,最大限度提高整体视频质量体验(QoE)和用户间的延迟上限.实验结果表明,该算法实现了用户间延迟和视频质量的最优组合,并论证了无线信道快速衰弱下的最优性能.     

现阶段IPTV面临的主要问题及其发展方向

IPTV也可以称为宽带网络电视,是基于IP协议的电视广播服务,通过互联网向用户提供视频、音频信息服务,主要论述IPTV的关键技术及其发展策略等问题。     

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.     

Resource Management and QoS Provisioning for IPTV over mmWave-based WPANs with Directional Antenna

There is an increasing interest in 60 GHz millimeter-wave (mmWave) communication technologies for multi-Gigabit wireless personal area networks (WPAN), aiming to support broadband multimedia applications. Internet Protocol TV (IPTV) is an emerging killer application which requires high data rate and stringent quality of services (QoS) in terms of delay and packet loss. In this paper, we propose a method to efficiently support high definition video flows in a mmWave-based WPAN with QoS guarantee, considering the characteristics of both the IPTV traffic and the mmWave communication technology. We first quantify the effective bandwidth of IPTV video sources using a simple, two-level Markov traffic model. Considering the overheads of the protocol stack in mmWave WPANs, we then quantify the minimum channel time needed for each IPTV flow. Since mmWave-based WPANs will deploy directional antennas to not only extend the transmission range, but also reduce the interference level to neighboring flows, we further propose an admission control scheme and scheduling algorithm to improve the network resource utilization by taking advantage of concurrent transmissions. Extensive simulations with NS-2 using real video traces have validated our analysis and demonstrated the efficiency and effectiveness of the proposed schemes, which will be an enabling technology for future mmWave-based WPANs supporting IPTV services. Part of this work was presented at 2008 Int. Conf. Heterogeneous Networking for Quality, Reliability, Security and Robustness (QShine’08), Hong Kong, July 2008. This work has been supported by research grants from the Natural Sciences and Engineering Research Council (NSERC) of Canada.     

基于服务器的IPTV快速频道切换技术

IPTV网络中的直播频道通常采用多播方式进行发送,STB通过加入多播组的方式来进行频道切换,这样使得IPTV频道切换往往比传统电视时间更长,在用户体验方面成为制约IPTV业务发展的硬伤。以CDN技术架构为基础,较详细地论述了基于服务器的FCC技术,该理论在实践中已得到应用,有较高的理论参考价值和实用价值。     

A QoE management system to improve the IPTV network

One of the biggest problems of the IPTV providers is to offer enough quality of experience (QoE) to their customers. The minimum bandwidth in the access network required to provide IPTV services, jointly with the necessity to guarantee the QoE to the customers, creates the need for new type of algorithms to satisfy the network requirements. Apart from the parameters that depend on the application aspect and design, the user's QoE mainly depends on the video quality (VQ), which can be affected by the network parameters (jitter, delay, lost packets, etc.), and on other parameters, such as zapping time and synchronization time. In this paper, we implement several benches to know how each measurable parameter affects the user's QoE. Taking into account these parameters, we propose an analytical expression for the QoE calculation. Then, the paper presents a network management algorithm that takes into account the information received by the user to take the appropriate actions and vary some features of the IP network to provide enough IPTV QoE to the customer. Finally, we measure how one of the actions taken by our system affects the network performance and the VQ. Copyright © 2010 John Wiley & Sons, Ltd.     

具负载平衡之IPTV影音串流系统

影音媒体具高带宽及实时特性,因此影音串流系统的服务质量的提升端赖影音服务器的有效管理。在此提出一套Video replication及Access request distribution的算法,藉由将热门影音分散到各影音服务器以及影音存取的分散,以达到各影音服务器系统负载平衡的效果。在此比较了3个不同的算法的负载平衡的状况,经实例验证,提出的算法确能达到影音服务器负载平衡的效果,承载更多的系统服务要求。该系统构建在Smart-i TV的IPTV系统台,并讨论了实作的相关技术。     

A cognitive network management system to improve QoE in stereoscopic IPTV service

New Internet Protocol Television (IPTV) services are including new technologies such as Stereoscopic TV and three‐dimensions (3D) HDTV. As well, increased ubiquitous networking and promoting in smart devices have led to high demand IPTV (over networks). Stereoscopic content required higher data flow to support these emerging TV services, and there are higher requirements at the network layer to provide good quality of service and quality of experience to the end users in delivering stereoscopic IPTV. In this paper, we propose a new concept of cognitive network management algorithm and protocol based on 3D coding techniques for delivering of stereoscopic IPTV service. The proposed approach explains how the management algorithm observes the network performance to guarantee the quality of the stereoscopic IPTV services, by measuring the performance of quality of service (QoS) parameters (delay, jitter, and packets loss) and quality of experience (QoE) metrics such as Peak Signal‐to‐Noise Ratio (PSNR), Moving Image Videography (MIV), and Mean Opinion Score (MOS). Those parameters are monitored in order to take appropriate codification decision for IPTV service provider. Moreover, the codification decision uses K‐mean classification to select the better codification for the end users. Therefore, both kinds of 3D coding formats such as Stereo Video Coding (SVC) format and 2D + Z Coding format (2D‐plus‐Depth) are selected in our experiments. As a result, our proposal successfully ensures the appropriate quality of service and quality of experience to the end users when the service of stereoscopic IPTV is being delivered.     

IPTV智能终端传输系统的设计和实现

随着IPTV技术的发展和服务商服务器端设备使用的多样性,如何设计高性能,高可靠性和高可扩展性的客户端软件并能连接不同的服务商成为了一个挑战性的课题。分析了IPTV传输系统的技术要求,并根据这些要求设计开发了一个IPTV智能客户端。提供了网络传输功能、丢包纠错功能、快速频道切换功能以及用户传输质量监控功能,并且可以很简单的集成到用户客户端中。可以和任何遵循IETF相关标准的服务器进行交互,大大提高了用户的视频观看质量,简化了用户IPTV客户端系统的开发时间。     

Advances in IPTV technologies

In the last couple of years we have seen the rise of IPTV from a cable and satellite replacement to more and more a service that encompasses both controlled and over the top content. Many reports¹ show a worldwide increase of IPTV subscribers of over 34%, with around 34 million new users in 2010 alone. Consolidated by this market penetration, IPTV is fast becoming a cost-efficient alternative for consuming television. Such rapid success has been made possible thanks to past research on video transmission over IP, on efficient decoding and rendering on the clients, and on quality of service and quality of experience. Nevertheless, there are still a number of challenges that need to be addressed to enable future growth. Some of these include: more efficient transmission mechanisms (e.g., peer to peer or P2P), convergent solutions (e.g., Over the Top or OTT services), improved quality of experience, and personalization. This special issue focuses in these areas, with the final intention of drawing a full picture on current and future advances in IPTV technologies.     

三网融合下视频业务质量评估体系的研究

随着三网络融合的推进,由电信运营的IPTV、手机影视等视频业务必将加速发展,对视频业务的质量评估和质量保障将日趋紧迫。本文探讨了基于用户主观体验的的视频质量评估模型和指标体系,并根据IPTV业务的特点,提出了适用的关键指标和指标阈值。视频质量评估模型和指标是构建IPTV等视频业务监测手段的关键,是提升视频质量监测评估不可或缺的重要前提。     

Measures to quantify the gain of multicast with application to IPTV transmissions via WiMAX networks

In applications like IPTV, multicasting provides beneficial services. However, due to overhead and problems of multicast transmission, multicasting is not always profitable. In order to make well-justified decisions whether it is worthwhile to use multicasting or not, its efficiency must be quantified. Therefore, the metric of ‘multicast gain’ is introduced as a measure for the bandwidth reduction which can be expected when using multicast (instead of multiple unicast). Different definitions for multicast gain are given to cover different types of links. As an application of our metric, multicast transmission of live TV channels in WiMAX-based access networks is analyzed. WiMAX as one of the 4G candidates can transmit IPTV services to mobile subscribers because of salient features such as multicast support, wide coverage range and high bandwidth. In OFDMA-based WiMAX the smallest logical bandwidth allocation unit is a slot. In this article, we use the term slot to measure the efficiency of multicasting in WiMAX networks. We show that for unpopular TV channels, using unicast flows can be preferable.     

省级IPTV监管平台技术研究

本文结合山西省IPTV的发展情况,提出了一种IPTV监管的方法,通过对IPTV集成播控平台、传输分发平台、用户终端的信息采集和数据分析处理,利用EPG信息分析管理、违规信息检测及取证、IPTV频道扫描、审批信息管理与核查、节目合法性鉴别、敏感信息共享等技术手段实现对IPTV技术质量、节目内容的有效监管,提高了广播电视信息安全的保障水平。