一种可支持多种多媒体业务的基于IMS的IPTV架构

IP多媒体子系统用于实现端到端的IP多媒体通信,具有接入无关性、对各种接入技术广适性的特点,因此,下一代网络采用IP多媒体子系统作为核心架构.提出一个基于IP多媒体子系统的IP电视架构,在IP多媒体子系统核心模块的基础上,以一组互相独立的基于会话初始化协议的功能模块构成应用服务器,并设计了能够支持和提供不同IM S业务的客户端与内容提供商端,使该IPTV框架可以在下一代网络上支持基于IP多媒体子系统的包括IPTV业务在内的多种多媒体业务.     

A service recovery method based on trust evaluation in mobile social network

Mobile social network makes users create and share multimedia contents freely and conveniently. However, some nodes in mobile social network have malicious behavior, such as discarding or tampering packet. These factors will cause service interruptions in the process of providing multimedia contents for the user. When the service interruption happens, how to choose the more reliable backup device, reduce interruption number, increase the packet transmission efficiency and improve user’s experience of sharing multimedia contents is the object of this paper. We propose a service recovery method based on trust evaluation which adopts Dempster-Shafer (D-S) evidence theory. The service requester calculates the direct trust degree and the recommended trust degree of the backup devices, then uses the evidence combination rule to calculate the comprehensive trust degree. The backup device with the highest trust value will be seclected to recover the service. The simulation results show that this method effectively improves the packet delivery ratio, reduces the service execution time and provides users with more stable multimedia contents.     

Content-aware replica placement strategy for IPTV services over peer-service area architecture

Due to the enormous improvement in networking and multimedia, IPTV has become recently a popular means to distribute high quality TV services over IP networks. Accordingly, Telecommunication companies started the competition to provide IPTV services to increase their customer base and profit. The key concern of service providers in this hectic competition is to provide high quality service with lower cost. However, the contents’ popularity and the users’ preferences are fluctuated rapidly, which leads to resources waste and load imbalance. Thus, the contents’ status should be considered during the content replication to save resources and reduce service cost. To the best of our knowledge, there is no work investigate the impact of contents’ status on building Replica Placement Strategy. Therefore, this paper studies the impact of contents’ status on replica placement strategy over the peer-service area architecture. Two optimization models are proposed Cost Effective Model (CE), which replicates the contents partially without considering contents’ status and Cost Effective with Load Balance model (CELB), which considers the contents’ status. Both models have been solved using Hybrid Genetic Algorithm. The experimental results show that CELB model outperforms the other models in terms of Storage Saving Ratio (SSR), load distribution, and allocation cost.

     

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.     

一种新型的基于IPTV网络的视频会话系统

基于IPTV网络的视频会话系统具有广阔的应用前景。研究并实现了一种基于IPTV网络的具有服务质量保证的新型视频会话系统,阐述了该系统的体系架构及业务流程,提出了适用于本视频会话系统的嵌入式IP机顶盒的体系架构,并针对嵌入式系统资源受限的特点进行了性能优化设计,特别提出了一种带宽自适应的QoS机制,充分保证视频会话应用在IPTV网络多业务环境下的用户体验。     

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.     

智能环境基于用户交互模态的情境感知服务

智能环境系统构成的复杂性和大量的情境信息增加了为用户提供和布局服务的难度。情境感知服务系统能感知系统运行和人机交互情境,根据相应的决策机制选择适当的设备为用户提供服务,从而简化环境设施的功能布局。在决策过程中引入用户交互模态信息有利于系统根据用户的交互能力和对人机界面的偏好提供服务。把情境细分为用户信息、设备信息、软件信息和环境拓扑信息,针对智能环境提出了一种基于用户交互模态的情境感知服务系统,同时详细说明了利用该技术选择服务的推理过程及其应用方法。通过智慧家庭环境中的场景案例验证了该系统的有效性。     

Classification algorithms for interactive multimedia services: a review

Interactive multimedia services, which integrate and unify techniques from a variety of disciplines, have been an active research topic for many years. However, two major challenges need to be overcome to provide a better service: The first is that interactive multimedia systems have to provide the contents a user needs at the right time no matter where the user is located and what device the user is using; the second is that the performance of such systems needs to be improved. Apparently, classification and clustering (also called unsupervised classification) algorithms play an indispensable role in these respects. Thus, this paper contains a review of the classification algorithms for interactive multimedia systems. Also discussed in this paper are several important issues, open questions, and trends.     

Adaptive IPTV services based on a novel IP Multimedia Subsystem

Heterogeneous communication devices are emerging and changing the way of communication. Innovative multimedia applications are now accessible through these embedded systems. The 3GPP IP Multimedia Subsystem (IMS) provides a basic architecture framework for the Next Generation Network (NGN) supporting the convergence platform for service provisioning in heterogeneous networks. ETSI TISPAN standardization effort focuses on delivering IPTV services on such platform. Nevertheless, IPTV on IMS standardization suffers from a lack of efficient user-centric network management mechanisms as the end-user may consume IPTV service from different access networks, on different mobile devices, at anytime. User’s Perceived Quality of Service (PQoS) or Quality of Experience (QoE) of IPTV service may also suffer from wireless access network impairments. This paper introduces new functionalities in IPTV over IMS architecture which optimize satisfaction of the end-user and resource utilization of the operator’s networks. A context-sensitive User Profile (UP) model is used to deliver IPTV streams adapted to the user’s environment. In order to optimize the operator network usage, the impact of spatiotemporal dynamics of the video content on the deduced perceptual quality is considered. A Multimedia Content Management System (MCMS) is proposed to perform dynamic cross-layer adaptation of the IPTV stream based on PQoS measurements at the end-user side.     

IPTV中互动电视业务的设计与实现

相对于传统的模拟电视到数字电视的转换,数字电视业务网络化传送业务模式不仅是向三网业务融合更迈进了一步,而且对于实现与视频节目内容同步的互动电视业务提供了新的方法.本文针对宽带网络IPTV业务环境,通过互动业务导引信息与视频节目内容的同步"推"及用户利用该导引信息"拉"的模式,提出了一种新的互动电视业务实现模式.该实现模式的主要特点在于基于DVB数据广播技术,将与视频内容同步的互动业务导引信息同步插入到电视节目的TS流中,用户端利用该导引信息,基于WEB方式实现互动业务.     

一种两阶段自适应的IMS-Based IPTV应用服务器负载均衡策略

随着IPTV用户数目的增长,IPTV应用服务器的负担愈加繁重。在这种情况下,集群系统逐渐成为构建高性能和高服务质量的一种有效的应用服务器体系结构。保证应用服务器各节点的负载均衡,可以有效提高系统的吞吐量,提高IPTV服务质量。针对负载均衡问题,提出了一种基于IPTV用户行为特点的,两阶段自适应负载均衡策略,负载均衡器通过实时监控应用服务器集群内各节点的负载情况,动态修改各节点负载分配权值。算法在保持应用服务器各节点负载均衡的同时,维护用户会话的完整性,保证了服务质量QoS（Quality of Services）。仿真结果显示此算法具有较好的性能,能在保证服务质量的前提下有效地提高系统吞吐量。     

利用组播及QoS技术对IPTV网络进行优化

主要阐述了有关IPTV网络业务、组播协议、Qos协议和OPNET网络仿真软件的有关基础知识,同时阐述了在业务承载网中的IPTV网络的发展现状,研究IPTV可能出现的网络传输拥塞时的缺点,提出基于组播和QoS技术的IPTV承载网络组网方案。重点阐述了OPNET的模型层次与构建方式,并提出了OPNET网络模拟仿真的具体步骤,通过OPNET软件进行模拟仿真实验,仿真中,按照数据业务、IP语音业务、IPTV服务等三个类型,分别对网络发射数量、终端接收数据流量、网络时延值和网络抖动数值等进行测试仿真,同时对所收集的网络状态信息进行数据分析。通过仿真实验,可以发现在IPTV网络中使用Qos及组播,有效减轻业务网的流量负荷,减少传输时延,提高网络系统稳定性,从而保证了相关服务的顺利进行。     

On performance of group key distribution techniques when applied to IPTV services

IPTV services consist of multiple video channels grouped in bundles, such as sports, movies or generic bundles; users typically subscribe multiple bundles, including the generic bundle. Secure IP multicast can be used to implement IPTV services, but it still has problems to be addressed. Current solutions require high computational power in video channel zapping situations, lack support for groups sourced at the users, and present a weak support for admission control in IP multicast for both sources and receivers in dynamically configured environments.This work proposes a new, secure and efficient IPTV solution that, cumulatively: (a) enforces individual access control to groups of real-time IPTV video channels; (b) enforces IP multicast admission control for both multicast senders and receivers; (c) supports user generated videos; (d) generates low signaling overheads; (e) does not introduce perceivable delays, particularly in video channel zapping situations. Moreover, this solution can be easily integrated in the IPTV architectures being developed by ETSI and ITU-T.     

OpenIPTV: a comprehensive SDN-based IPTV service framework

IPTV is an emerging TV content delivery service that should guarantee Quality of Service (QoS) to deliver television contents over IP for their customers. However, providing such QoS regarding service level agreements (SLA) requires frequent service monitoring and adaptive configuration mechanisms. Nowadays, Software Defined Networks (SDNs) provide capabilities to deploy and manage networks dynamically and can maintain QoS. In this paper, a novel IPTV service framework (OpenIPTV) is proposed, which utilizes SDN as an underlying technology for providing QoS for IPTV customers in a shared backbone network. OpenIPTV is implemented in a well-known OpenDayLight controller and strictly followed a modular design for the sake of efficiency. OpenIPTV comprises all service requirements such as resource monitoring, channel changing, multicast group managing and dynamic QoS multicast traffic engineering. The performance of OpenIPTV is evaluated under different scenarios and experimental results confirmed the effectiveness of the proposed framework in terms of QoS metrics. Furthermore, experimental results show that OpenIPTV is a feasible and practical solution to deliver IPTV services with high level of QoS over SDN.     

ViMediaNet: an emulation system for interactive multimedia based telepresence services

The telepresence service (TPS) leverages advanced communication, virtual reality, and cooperative web technologies to provide remote engaged users an immersive experience of being fully present, which are widely used in teleconferencing, remote surgery, and hazardous environment exploration. The common feature of TPS-based applications lies in that the users’ experiences heavily depend on the quality of interactive multimedia services, that is, most deliveries of multimedia contents are mission-critical, as well as time-critical, to ensure the control and operation accuracy for telerobots. Therefore, the delivery performance of multimedia contents over heterogeneous networks becomes the primary concern in the TPS system design, especially for those delay sensitive applications, like remote surgery and environment exploration. In this paper, we incorporate video processing tools with the network simulator to design and implement a joint emulation system, named as the virtual media network (ViMediaNet), through which, the TPS designer can readily deploy the TPS system over a heterogeneous network virtualized by the network emulator, investigate the critical network performance metrics in the multimedia content delivery, such as transmission delay and packet jitter, and observe control results in real time. To verify the capability of ViMediaNet in emulating the real-setting TPS system, we take a mobile device based vision navigation system as an example to evaluate performance impacts of the rate adaptation technology in the telerobot control. The experimental results reveal that the adaptive video streaming is a promising solution to significantly enhance the control accuracy of telerobots in TPS systems.     

网络传输中IPTV的QoE评估模型的研究

IPTV是一种基于Internet的多媒体网络服务,由于Internet本身的不可靠性,使其在网络传输过程中无法保证服务质量。为了实时定量评估IPTV服务质量,提出了一种基于IPTV的用户体验评估模型,通过建立从网络服务质量QoS到用户体验质量QoE的映射关系,借助QoS测量技术,以实现针对QoE的在线评估。实验建立IPTV仿真平台,模拟真实网络环境下IPTV媒体流传输的整个过程,实现网络损伤QoS可控和QoE可测。针对不同编码和不同内容的视音频,分别建立独立的QoE评估模型。同时考虑到模型对数据精度和计算速度的需求,给出优化的QoE评估模型。实验结果表明,该评估模型与实际用户体验具有较高的拟合度。     

基于LFOA-HSRVM的IPTV用户报障预测方法

针对交互式网络电视(IPTV)用户报障因素复杂、故障样本相对贫瘠的问题,基于相关向量机(RVM)高稀疏性的建模特点提出一种结合RVM参数优化和混合采样的IPTV用户报障预测方法(LFOA-HSRVM)。该方法将IPTV的用户报障预测视为一个针对非均衡数据集的二分类问题,克服了传统RVM算法在处理非均衡数据时决策边界偏向少数类样本的问题。实验表明,与其他相关算法相比,该算法的少数类分类性能和总体分类性能均有较大提升,能获得更好的报障预测效果。     

A network algorithm for 3D/2D IPTV distribution using WiMAX and WLAN technologies

The appearance of new broadband wireless technologies jointly with the ability to offer enough quality of service to provide IPTV over them, have made possible the mobility and ubiquity of any type of device to access the IPTV network. The minimum bandwidth required in the access network to provide appropriate quality 3D/2D IPTV services jointly with the need to guarantee the Quality of Experience (QoE) to the end user, makes the need of algorithms that should be able to combine different wireless standards and technologies. In this paper, we propose a network algorithm that manages the IPTV access network and decides which type of wireless technology the customers should connect with when using multiband devices, depending on the requirements of the IPTV client device, the available networks, and some network parameters (such as the number of loss packets and packet delay), to provide the maximum QoE to the customer. The measurements taken in a real environment from several wireless networks allow us to know the performance of the proposed system when it selects each one of them. The measurements taken from a test bench demonstrate the success of our system.     

Wireless resource management mechanism with green communication for multimedia streaming

In the face of massive parallel multimedia streaming and user access, multimedia servers are often in an overload state, resulting in the delay of service response and the low utilization of wireless resources, which makes it is difficult to satisfy the user experience quality. Aiming at the problems of low utilization rate of multimedia communication resources and large computing load of servers, this paper proposes a self management mechanism and architecture of wireless resources based on multimedia flow green communication. First, based on the combination of multimedia server, relay base station and user cluster, a multimedia green communication system architecture is built based on the comprehensive utilization rate of multimedia communication, and a cluster green communication control algorithm is proposed. Secondly, aiming at the dynamic service demand and asynchronous multimedia communication environment, aiming at ensuring the balance of resource allocation and accelerating the speed of resource allocation, we build a dynamic multimedia wireless resource architecture. Finally, the experimental results of statistics and analysis, from the server in different scale parallel multimedia streams under different scale delay, number of users relay network free resources proportion, user satisfaction, packet loss rate and other performance show that the proposed algorithm is effective and feasible.