Aggregate bandwidth estimation in stored video distribution systems

Multimedia applications like video on demand, distance learning, internet video broadcast, etc. will play a fundamental role in future broadband networks. A common aspect of such applications is the transmission of video streams that require a sustained relatively high bandwidth with stringent requirements of quality of service. In this paper various original algorithms for evaluating, in a video distribution system, a statistical estimation of aggregate bandwidth needed by a given number of smoothed video streams are proposed and discussed. The variable bit rate traffic generated by each video stream is characterized by its marginal distribution and by conditional probabilities between rates of temporary closed streams. The developed iterative algorithms evaluate an upper and lower bound of needed bandwidth for guaranteeing a given loss probability. The obtained results are compared with simulations and with other results, based on similar assumptions, already presented in the literature. Some considerations on the developed algorithms are made, in order to evaluate the effectiveness of the proposed methods. Copyright © 2002 John Wiley & Sons, Ltd.     

Real-time VBR video traffic prediction for dynamic bandwidth allocation

In this paper, we systematically investigate the long-term, online, real-time variable-bit-rate (VBR) video traffic prediction, which is the key and complicated component for advanced predictive dynamic bandwidth control and allocation framework for the future networks and Internet multimedia services. We focus on neural network-based approach for traffic prediction and demonstrate that the prediction performance and robustness of neural network predictors can be significantly improved through multiresolution learning. We show that neural network traffic predictor trained through the multiresolution learning (called multiresolution learning NN traffic predictor) can successfully predict various real-world VBR video traffic up to hundreds of frames in advance, which then lays a solid foundation for predictive dynamic bandwidth control and allocation mechanism. Also, dynamic bandwidth control/allocation based on long-term traffic prediction is discussed in detail.     

Traffic shaping, bandwidth allocation, and quality assessment forMPEG video distribution over broadband networks

This article provides an overview of residential video delivery systems and presents the applications, benefits, and challenges of using VBR MPEG video encoding in broadband video distribution networks. The network resources required to transmit stored variable-rate MPEG can be reduced by properly analyzing and smoothing the video stream before transmission. A scheduling technique is presented which selects a traffic contract for a pre-encoded MPEG video stream with the criteria of minimizing network resources and maintaining video quality. Several effective bandwidth metrics are discussed and used to model the potential savings in network resources for the shaped streams     

Partial video sequence caching scheme for VOD systems withheterogeneous clients

Video on demand (VOD) is one of the key applications in the information era. A hinge factor to its widespread use is the huge bandwidth required to transmit digitized video to a large group of clients with widely varying requirements. This paper addresses issues of heterogeneous clients by proposing a program caching scheme called the partial video sequence (PVS) caching scheme. The PVS caching scheme decomposes video sequences into a number of parts by using a scalable video compression algorithm. Video parts are selected to be cached in local video servers based on the amount of bandwidth that would be demanded from the distribution network and central video server if it was only kept in the central video server. We also show that the PVS caching scheme is suitable for handling vastly varying client requirements     

Optimal bandwidth allocation for the data and feedback channels in MISO-FDD systems

In frequency-division duplex (FDD) systems, channel-state information (CSI) is estimated by the receiver and then fed back to the transmitter through a feedback link, which inevitably requires additional bandwidth and power. In this letter, we jointly study optimal bandwidth allocation between the data channel, modeled as a flat-fading multiple-input single-output (MISO) channel, and the feedback channel for maximum average throughput in the data channel using a beamforming scheme. We consider two models of the partial CSI at the transmitter (CSIT): the noisy CSIT, modeled as jointly Gaussian with the actual channel state, and the quantized CSIT. In the first model, we use distortion-rate theory to relate the CSIT accuracy to the feedback-link bandwidth. In the second model, we derive a lower bound on the achievable rate of the data channel based on the ensemble of a set of random quantization codebooks. We show that in the MISO flat-fading channel case, beamforming based on feedback CSI can achieve an average rate larger than the capacity without CSIT under a wide range of mobility conditions.     

Dynamic bandwidth allocation with fair scheduling for WCDMA systems

Dynamic bandwidth allocation (DBA) will play an important role in future broadband wireless networks, including the 3G and 4G WCDMA systems. A code-division generalized processor sharing (CDGPS) fair scheduling DBA scheme is proposed for WCDMA systems. The scheme exploits the capability of the WCDMA physical layer, reduces the computational complexity in the link layer, and allows channel rates to be dynamically and fairly scheduled in response to the variation of traffic rates. Deterministic delay bounds for heterogeneous packet traffic are derived. Simulation results show that the proposed CDGPS scheme is effective in supporting differentiated QoS, while achieving efficient utilization of radio resources.     

Predictive dynamic bandwidth allocation for efficient transport ofreal-time VBR video over ATM

This paper presents a novel approach to dynamic transmission bandwidth allocation for transport of real-time variable-bit-rate video in ATM networks. Video traffic statistics are measured in the frequency domain. The low-frequency signal captures the slow time-variation of consecutive scene changes while the high-frequency signal exhibits the feature of strong frame autocorrelation. Our queueing study indicates that the video transmission bandwidth in a finite-buffer system is essentially characterized by the low-frequency signal. We further observe in typical JPEG/MPEG video sequences that the time scale of video scene changes is in the range of a second or longer, which localizes the low-frequency video signal in a well-defined low-frequency band. Hence, in a network design it is feasible to implement dynamic allocation of video transmission bandwidth using on-line observation and prediction of scene changes. Two prediction schemes are examined: recursive least square method and time delay neural network method. A time delay neural network with low-complexity high-order architecture, called “pi-sigma network,” is successfully used to predict scene changes. The overall dynamic bandwidth-allocation scheme presented is shown to be promising and practically feasible in obtaining efficient transmission of real-time video traffic     

Architecture of multi-OLT PON systems and its bandwidth allocation algorithms

In this paper, we propose a novel passive optical network (PON) architecture that has multiple optical line terminals (OLTs). Unlike existing PONs where all ONUs are connected to a single OLT, the proposed multi-OLT PON allows subscribers to choose their own service providers from among multiple OLTs. Service companies and subscribers can make service level agreements (SLA) on the amount of bandwidth that each OLT or ONU requires. A new control protocol and bandwidth allocation algorithms appropriate in this new PON environments are suggested. For the downstream, a scheme to share the bandwidth among multiple OLTs is studied to maximize the total transmitted packets while guaranteeing each OLT’s SLA. A modified Limited Dynamic Bandwidth Allocation named mLimited scheme is also proposed for upstream transmission toward multiple OLTs, which maximizes the total upstream throughput while minimizing the delay of each ONU. Performances of the proposed PON architecture and algorithms are analyzed. A PON system with two OLTs and 16 ONUs is used in the analysis. Self-similar traffic reflecting current packet distribution is used in the packet generation. The results show that the proposed DBA schemes efficiently manage bandwidth even when the occurred traffic load is quite different from the reserved bandwidth. It is found that the proposed PON architecture is appropriate in supporting diverse services in future high-speed optical access network.     

UNIFORM—PRICE AUCTION FOR BANDWIDTH ALLOCATION IN THE INTERNET

It has been widely accepted that auctioning which is the pricing approach with minimal information requirement is a proper tool to manage scare network resources.Previous works focus on vickrey auction which is incentive compatible in classic auction theory.In the beginning of this letter,the faults of the most representative auction-based mechanisms are discussed.And then a new method called Uniform-Price Auction(UPA),which has the simplest auctiopn rule is proposed and its incentive compatibility in the network environment is also proved.Finally,the basic mode is extended to support applications which require minimum bandwidth guarantees for a given time period by introducing derivative market.and a market mechanism for network resource allocation which is predictable,riskless,and simple for eng-users is completed.     

一种保证EPON系统QoS的预估DBA算法

文章提出一种保证以太无源光网络(EPON)系统服务质量(QoS)的预估动态带宽分配(DBA)算法,该算法把多个子周期组合为一个超周期,在超周期中预估各级业务带宽,然后在子周期内参考预估值进行带宽分配;并对用户上行数据进行接入管理,维持QoS的稳定.实验结果表明,该算法既能保证各级业务的带宽利用率和时延要求,又能提供更加稳定的QoS.     

基于拍卖的P2P内容分发网络带宽分配机制

为了解决P2P内容分发网络中带宽资源稀缺且分配不合理这一突出问题,抑制节点的自私性行为,设计了一种基于拍卖的带宽分配机制。该机制通过上载带宽支付方式,迫使自私请求节点选择合适的带宽需求,使得整个P2P网络中的节点良性竞争带宽资源,避免了"公共地悲剧"的发生;且带宽分配算法在资源节点和请求节点并行执行,能很好适应P2P网络的分布式特性。仿真结果表明,该机制能够有效遏制搭便车行为,从而缩短P2P内容分发的平均完成时间,降低内容源服务器的上传数据比例。     

Extending critical bandwidth allocation techniques for stored video delivery across best‐effort networks

In this paper, we propose two new techniques for the delivery of compressed prerecorded video streams across best‐effort networks like the Internet. Current approaches for the delivery of stored video across best‐effort networks typically alter the quality of the video frames, the frame rate delivered to the user, or a combination of both. By using network feedback, these algorithms continually adjust the video quality to fit within the available network resources. These approaches, however, do not take advantage of the a priori information available from stored video streams, namely the frame sizes that the movie consists of. We will show how monitoring the a priori information and actively monitoring a client‐side buffer can help smooth the video frame rate delivered to the user, providing a more consistent quality of video. Copyright © 2001 John Wiley & Sons, Ltd.     

Hierarchical distribution of video with dynamic port allocation

A two-level distribution network for broadcast and interactive video is studied as an example of the hierarchical distribution method. This two-level design has the following advantages: it facilitates switch growth and enhances switch reliability; it reduces the overall circuit mileage of the video distribution system; and video requests can be processed independently by local switches, rendering a large call processor at the central switch unnecessary. A traffic model for this network is formulated and the optimum capacities of the central and local switches are determined for a given blocking requirement. By adding a small crosspoint switch between the two levels, the output ports of the central switch can be dynamically allocated to the local switches. This sharing of output ports can significantly reduce the size of the central switch     

Dynamic bandwidth allocation for multimedia traffic with rate guarantee and fair access in WCDMA systems

Packet scheduling in a WCDMA system poses a new challenge due to its nature of variable bit rates and location-dependent, time-varying channel conditions. In this work, three new downlink scheduling algorithms for a WCDMA base station are proposed to support multimedia transmissions. Using a credit management and a compensation mechanism, our algorithms provide rate guarantee and fair access to mobile terminals. In particular, we propose to allow a user to simultaneously use multiple OVSF codes in a time-sharing manner, which we call a multicode, shared model. Using multiple codes allows us to compensate those users suffering from bad communication quality or even errors. The proposed schemes can tolerate a multistate link condition (compared to the typically assumed two-state, or good-or-bad, link condition) by adjusting the number of OVSF codes and the spreading factor of each code. Simulation results show that the proposed schemes do achieve higher bandwidth utilization while keeping transmission delay low.     

EPON中一种动态带宽分配算法

以太无源光网络(EPON)被认为是下一代宽带接入的最有效的解决方案。文章提出了一种新的基于EOPN提供多种服务的动态带宽分配算法。为了能够应用这种算法还给出了协助带宽分配多点控制协议(MPCP)的控制消息的格式。     

29 GHz radio systems for video distribution and transmissionapplications

A 29 GHz radio system was initially developed to solve difficulties with providing a satellite-based racing information video distribution service direct to business customers where satellite antennas could not be provided at the customers' premises. The system was used for the final link for distributing the service. Short-range distribution is provided from a 29 GHz transmitter to a number of receivers within a circular coverage area. The system has also been adapted to provide point-to-point video transmission for other services. Minimum-cost manufacturing techniques were considered from the outset to ensure that the radio equipment could be produced at low cost in the production volumes anticipated     

Dynamic bandwidth allocation for interactive applications

The transmission of stored video across an ATM network is considered for interactive applications with bounded reaction times. The performance of the services renegotiated VBR (RVBR) and renegotiated CBR (RCBR) is investigated for this class of applications by trace-driven simulations. The goal is to determine the most efficient service for interactive applications. Here we present three basic results. First, for delay sensitive applications smoothing the video stream in advance is much more efficient than adding smoothing buffers to the network switches. Second, services with renegotiation (RCBR, RVBR) are better suited for interactive applications than the static services CBR and VBR. Third, the RVBR service with a deterministic call admission control scheme is the best choice for interactive applications that require small reaction times.     

企业级视频会议动态时间槽多播带宽提前预留算法

为了保证视频会议的服务质量和提高企业网络资源利用率,研究了企业级视频会议系统带宽提前预留问题。在企业级网络中经常出现同时在线会议数量多达数百个量级的情况,而且任意两个会议成员之间都有可能视频通信。为会议提前预留带宽将导致未来可用带宽随时间而呈细粒度变化,特别是同时出现大量会议请求时,时间开销和带宽使用将大幅度增长。为解决此问题,提出了动态时间槽多播带宽提前预留算法。该算法综合考虑了IETF XCON工作小组提出的两种不同会议场景。仿真结果表明,相比其他算法,该算法能够有效地给大数据会议申请预留带宽,解决时间开销瓶颈问题。     

Optimal allocation of bandwidth for source coding, channel coding, and spreading in CDMA systems

This paper investigates the tradeoffs between source coding, channel coding, and spreading in code-division multiple-access systems, operating under a fixed total bandwidth constraint. We consider two systems, each consisting of a uniform source with a uniform quantizer, a channel coder, an interleaver, and a direct-sequence spreading module. System A is quadrature phase-shift keyed modulated and has a linear block channel coder. A minimum mean-squared error receiver is also employed in this system. System B is binary phase-shift keyed modulated. Rate-compatible punctured convolutional codes and soft-decision Viterbi decoding are used for channel coding in system B. The two systems are analyzed for both an additive white Gaussian noise channel and a flat Rayleigh fading channel. The performances of the systems are evaluated using the end-to-end mean squared error. A tight upper bound for frame-error rate is derived for nonterminated convolutional codes for ease of analysis of system B. We show that, for a given bandwidth, an optimal allocation of that bandwidth can be found using the proposed method.     

GPON中的动态带宽分配

首先介绍了吉比特无源光网络(GPON)的复用结构和所承载的业务,随后就GPON的关键技术之一——动态带宽分配作了详细论述,分别从带宽分配的功能、对象和过程这几个方面作了介绍,最后比较了GPON和宽带无源光网络(BPON)在动态带宽分配方面的不同。