Reliability-oriented ant colony optimization-based mobile peer-to-peer VoD solution in MANETs

Mobile peer-to-peer (MP2P) has emerged as a state-of-the-art technology for video resource sharing in mobile ad-hoc networks (MANETs), building on the advantages of P2P data exchange and providing a feasible solution for large-scale deployment of media streaming services. Fast search for video resources and low maintenance overhead of overlay networks to support the mobility of nodes are key factors in MP2P video on demand solutions. In this paper, we propose a novel reliability-oriented ant colony optimization (ACO)-based MP2P solution to support interactivity for video streaming in MANETs (RACOM). RACOM makes use of highly innovative algorithms such as the peer status-aware mechanism and peer-centric overlay maintenance mechanism to support high-efficiency video resource sharing. The peer status-aware mechanism includes the user reliability measure model which is used to identify the peers having reliable playback status in order to find stable potential resource suppliers and a new ACO-based prediction model of playback behavior which provides the accurate prediction of playback content in the future to ensure the smooth experience and optimize the distribution of resources. In order to balance the fast supplier discovery and low maintenance overhead, RACOM makes use of peer-centric overlay maintenance mechanism composed of the time window-based detection strategy and encounter-based synchronization strategy to reduce the maintenance overhead of reliable peers, obtain quasi real-time status of peers and support the mobility of mobile nodes. Simulation results show how RACOM achieves higher hit ratio, lower seek delay, lower server stress, lower peer load and less overlay maintenance overhead in comparison with another state of the art solution.     

Virtual community-based video resource sharing solution in MANETs

The virtual community has emerged as a state-of-the-art technology, grouping the user with the common interest and providing a feasible solution for large-scale deployment of resource sharing services. Efficient sharing for video resources and low maintenance cost of overlay topology are key factors in MP2P video on demand systems. In this paper, a novel virtual community-based video resource sharing (VCVRS) solution in MANETs is proposed. VCVRS design a virtual community construction strategy to group the nodes with the common playback behavior and a flexible community maintenance mechanism so as to obtain the fast supplier discovery and low maintenance overhead. Simulation results show how VCVRS achieves higher lookup success rate, lower server stress, lower node load and less overlay maintenance overhead, in comparison with another state of the art solution.     

P2P流媒体模型的资源传输机制

针对流媒体的点播和直播服务,提出了基于P2P的流媒体应用层多播和点播的解决方案,构建了基于超级节点和普通节点的两层体系结构的视频流媒体模型.描述了模型的总体结构,分析了资源传输机制.基于校园网对模型进行了测试,测试结果表明,模型能够实现基于流媒体应用的多点数据快速互传.     

构建移动互联网应用基础设施——打造“开放花园”

良好的移动互联网应用基础设施,从用户接入层面可以为用户提供接入移动互联网应用的便捷通道;从业务提供的层面可以提高用户访问速度和业务质量,加强对内容资源的掌控力度,降低内容存储成本和管理开销;从业务层面可以降低业务开发门槛和运营维护成本,提升业务上线速度。文章建议国家应立足于现有网络,从战略高度推动移动互联网应用基础设施的技术研究和产业化进程。     

Cross-layer optimization for SVC video delivery over the IEEE 802.11e wireless networks

The Scalable Video Coding (SVC) standard extends the H.264/AVC with scalability support and is effective to adapt bitrate to the time-varying wireless channel bandwidth. In this paper, we propose a cross-layer optimization scheme, which includes packet prioritization and QoS mapping, for the delivery of SVC over the IEEE 802.11e wireless networks. The proposed structure enables interaction among different network layers, providing differentiated services for video packets. Our cross-layer optimization performs with the following information: (i) SVC packet prioritization at the application layer, (ii) service differentiation at the MAC layer, and (iii) interface queue (IFQ) occupation status at the link layer. We formulate the QoS mapping problem as a joint optimization of access category (AC) assignment and IFQ control. A novel and efficient solution is proposed to reduce the computational complexity of the joint optimization problem. Simulation results show that the proposed approach achieves notable improvement when compared to conventional methods.     

A traffic control system for IEEE 802.11 networks based on available bandwidth estimation

To support Quality of service (QoS)‐sensitive applications like real‐time video streaming in IEEE 802.11 networks, a MAC layer extension for QoS, IEEE 802.11e, has been recently ratified as a standard. This MAC layer solution, however, addresses only the issue of prioritized access to the wireless medium and leaves such issues as QoS guarantee and admission control to the traffic control systems at the higher layers. This paper presents an IP‐layer traffic control system for IEEE 802.11 networks based on available bandwidth estimation. We build an analytical model for estimating the available bandwidth by extending an existing throughput computation model, and implement a traffic control system that provides QoS guarantees and admission control by utilizing the estimated available bandwidth information. We have conducted extensive performance evaluation of the proposed scheme via both simulations and measurements in the real test‐bed. The experiment results show that our estimation model and traffic control system work accurately and effectively in various network load conditions without IEEE 802.11e. The presence of IEEE 802.11e will allow even more efficient QoS provision, as the proposed scheme and the MAC layer QoS support will complement each other. Copyright © 2006 John Wiley & Sons, Ltd.     

A cross-layer framework for multi-layer-video multicast with QoS requirements in multirate wireless networks

We propose a cross-layer framework for efficient multi-layer-video multicast with rate adaptation and quality-of-service (QoS) requirements in multirate wireless networks. We employ time division multiple access at the physical layer to transmit different video layers' data. The multicast sender then dynamically regulates the transmission rate and time-slot allocation based on the channel state information (CSI) and loss QoS requirements imposed by upper protocol layers. Under our proposed cross-layer framework, we first design a rate adaptation algorithm to fulfill the diverse loss QoS requirements for all video layers while achieving high multicast throughput. We then develop a time-slot allocation scheme which synchronizes data transmission across different video layers. Also conducted are simulation results to validate and evaluate our designed adaptive multicasting schemes under the proposed cross-layer framework.     

针对移动视频流介于UMTS和WiMAX网络间的切换方案

下一代移动网络(NGMN)倾向于融合多个无线接入技术(RATs)来为用户提供无处不在的访问服务。而作为一个无处不在系统,能够有一个解决方案来支持日益流行的视频应用程序也是至关重要的。由于移动视频应用程序的高带宽要求和对延迟敏感的特点,如何让移动视频应用程序在不同的RATs之间进行无缝切换并保证服务质量(QoS)是我们面临的一个挑战。为了加快实现在异构网络中提供无缝视频流服务,通过运用IEEE 802.21规定的媒体独立信息服务的服务器提出了一种移动端发起-网络端控制的移动网络切换方案。仿真结果表明,该方案在丢包率、延迟和峰值信噪比等方面提高了性能。     

Extending P2PMesh: topology‐aware schemes for efficient peer‐to‐peer data sharing in wireless mesh networks

Wireless mesh networks (WMNs) have emerged as a promising technology that provides low‐cost broadband access to the Internet for fixed and mobile wireless end users. An orthogonal evolution in computer networking has been the rise of peer‐to‐peer (P2P) applications such as P2P data sharing. It is of interest to enable effective P2P data sharing in this type of networks. Conventional P2P data sharing systems are not cognizant of the underlying network topology and therefore suffer from inefficiency. We argue for dual‐layer mesh network architecture with support from wireless mesh routers for P2P applications. The main contribution of this paper is P2PMesh: a topology‐aware system that provides combined architecture and efficient schemes for enabling efficient P2P data sharing in WMNs. The P2PMesh architecture utilizes three schemes: (i) an efficient content lookup that mitigates traffic load imbalance at mesh routers; (ii) an efficient establishment of download paths; and (iii) a data transfer protocol for multi‐hop wireless networks with limited capacity. We note here that the path establishment and data transfer schemes are specific to P2P traffic and that other traffic would use routes determined by the default routing protocol in the WMN. Simulation results suggest that P2PMesh has the potential to improve the performance of P2P applications in a wireless multi‐hop setting; specifically, we focused on data sharing, but other P2P applications can also be supported by this approach. Copyright © 2011 John Wiley & Sons, Ltd.