Rate renegotiation algorithm with dynamic prediction window for efficient transport of streaming VBR MPEG coded video over ATM networks

The major driving force behind the emergence of broadband integrated networks is traffic from video sources. For video sources, the Moving Picture Experts Group (MPEG) compression scheme was proposed several years ago and it has become the defacto standard for video compression. However, even with the huge reduction of bits that MPEG compression provides, it does not smooth the video traffic. Indeed, the MPEG compression algorithm guarantees that the MPEG stream will be bursty. A service is considered where a client requests and receives MPEG coded video sequences from an asynchronous transfer mode (ATM) server. An algorithm for streaming MPEG coded video delivery over ATM networks that dynamically allocates the transmission parameters is proposed. Simulation results with regard to this algorithm are presented. The results obtained show that the proposed dynamic allocation algorithm can provide an efficient solution for MPEG coded video transport with guaranteed quality of service (QoS) over ATM networks.

A fuzzy approach to MPEG video transmission in ATM networks

Hurst Parameter Estimation of Long-Range Dependent VBR MPEG Video Traffic in ATM Networks

Video traffic is expected to account for a significant share of the traffic volume in future asynchronous transfer mode (ATM) networks. MPEG-2, proposed by the Moving Picture Expert Group, is one of the most promising compression techniques for such applications. One of the critical issues in MPEG-2 is to realize effective variable bit rate (VBR) video transfer thorough ATM networks. The leaky bucket (LB) scheme has been widely accepted as the usage parameter control (UPC) mechanism to police the VBR sources. We propose a new adaptive dynamic leaky bucket (ADLB) congestion control mechanism, which is based on the LB scheme. Unlike the conventional LB, the leak rate of the ADLB is controlled using delayed feedback information of available bandwidth sent by the network. The simulation results show that overall cell loss and delay are reduced significantly at the ATM switch node.

Video traffic is expected to account for a significant share of the traffic volume in the future asynchronous transfer mode (ATM) networks. MPEG-2 proposed by Moving Picture Expert Group is one of the most promising compression techniques for such applications. One of the critical issues in MPEG-2 is to realize effective variable bit rate (VBR) video transfer thorough ATM networks. The Leaky Bucket (LB) scheme has been widely accepted as the usage parameter control (UPC) mechanism to police the VBR sources. We proposed a new Adaptive Dynamic Leaky Bucket (ADLB) congestion control mechanism, which is based on the LB scheme. Unlike the conventional LB, the leak rate of the ADLB is controlled using delayed feedback information of available bandwidth sent by the network. This scheme allows sources to get varying amounts of bandwidth over time, while reserving a minimum guaranteed bandwidth (MCR) for the entire duration of the connection. At the time of congestion, the leak rate of the ADLB is adjusted according to the feedback indicating the currently available bandwidth to the connection. The simulation results show that the end-to-end cell transfer delay and cell loss of each source has been improved significantly.

Video traffic is expected to account for a significant share of the traffic volume in the future asynchronous transfer mode (ATM) networks. MPEG-2, proposed by the Moving Picture Expert Group, is one of the most promising compression techniques for such applications. One of the critical issues in MPEG-2 is to realize effective variable bit rate (VBR) video transfer thorough ATM networks. The Leaky Bucket (LB) scheme has been widely accepted as the usage parameter control (UPC) mechanism. The authors propose an explicit rate congestion control mechanism based on the LB scheme. Unlike the conventional LB, the leak rate is controlled using delayed feedback information sent by the network. The results show that cell loss and delay are reduced significantly at the ATM switch node.

The overall aim of the paper is concerned with transmission of a digital video signal over an asynchronous transfer mode (ATM) network, using a self-organizing fuzzy (SOF) controller. In ATM a traffic-shaping buffer is used to prevent excessive back-to-back cells being generated during the peak transmissions of Moving Picture Expert Group (MPEG) variable bit rate (VBR) data sources. The VBR data sources are unpredictable and have substantial variations in bit rate, which could result in data loss and therefore image quality degradation. In this research, a self-organizing fuzzy controller is applied to digital video to eliminate excessive delay or loss at the user network interface. A self-organizing fuzzy controller adjusts the traffic-shaping buffer output rate frame by frame to enable the VBR encoded video to conform to the leaky bucket's contract. A rule-based fuzzy (RBF) controller regulates the average arrival rate to the traffic-shaping buffer to prevent either overflow or starvation of the buffer on a group of picture (GOP) by GOP basis. The computer simulation results demonstrate that the use of a SOF controller reduces excessive delay and data loss at the user network interface as compared with a conventional policing mechanism in ATM.

This paper presents a RITM (real-time integrated traffic management) scheme that can effectively manage VBR (variable bit rate) and ABR (available bit rate) cell services having unpredictable characteristics in ATM (asynchronous transfer mode) networks. In addition to its exact traffic monitoring capability, the proposed scheme intends to efficiently use network resources without any deterioration in QoS (quality of service) of the accepted connections. Specifically, we highlight some functions of resource management, connection admission control that should be integrated to operated correctly in the emerging ATM networks. This enables ATM switch designers to find a suitable buffer design method. An unique feature of this scheme is that it has a special ATM cell control block, which makes it possible to manage ATM traffic in real-time so that the delay incurred to measure the cell arrival rate in existing algorithms is removed. By doing this, we can also save ATM switch buffers fairly, which means that those buffers would be used for more users or ABR services. This property makes the scheme extremely attractive for supporting most delay-sensitive and loss-sensitive applications at the same time without changing the existing ATM environments. The proposed RITM scheme has been verified to reliably monitor incoming traffic and to efficiently manage network resources by simulations.

Design and performance analysis of a new RTM algorithm for VBR traffic in ATM networks

The highly bursty nature of the moving picture experts group (MPEG) determines the bandwidth when it is applied to the asynchronous transfer mode (ATM) deterministic bit rate (DBR) service class. Furthermore, the MPEG source must declare peak cell rate (PCR), one of the traffic descriptors used in the call admission control (CAC) procedure, before actual transmission in ATM networks. However, the real-time encoding of the MPEG video introduces a difficulty in predicting a maximum picture size of the video, which is necessary to determine PCR. When an MPEG source can be equipped with the capability to adjust the encoding rate to the allocated bandwidth, the burstiness of the MPEG video can be lowered and the uncertainty in predicting PCR is avoided to some extent. In this case, a problem is apparently quality degradation caused by introducing such a rate adaptation mechanism, which is the main subject of this study. For the rate adaptation method, we consider a priority control method, a space reduction method, a time reduction method and a bandwidth renegotiation method. Quality of the video is evaluated and compared in terms of signal-to-noise ratio (SNR) as well as mean opinion score (MOS) because users' perception becomes an important measure of the quality of video transmissions. Through experimental results, it is shown that the space reduction method is useful for real-time transmission, whereas the time reduction method can be applicable if the users' application can tolerate the relatively large delay between source and destination. Furthermore, the applicability of the bandwidth renegotiation method is also validated. © 1997 by John Wiley & Sons, Ltd.

The arrangement of data in a variable bit rate (VBR) video codec, making it suitable for the transmission over ATM (asynchronous transfer mode) networks, is addressed. Attention is focused on two aspects specifically belonging to the ATM environment: the impairment due to the loss of ATM data cells and the statistical analysis of a real VBR video source. A particular implementation of a hybrid DCT (discrete cosine transform) broadcast video codec, which adheres to the recent specifications proposed by the European Telecommunications Standards Institute, is addressed. In order to optimize the performance with respect to cell losses, a specific solution based on the concept of organizing data into video packets is explored. The statistical characteristics of the available VBR video source are investigated, using a real-time acquisition system. >

This paper investigates the application of multicode spread-spectrum code-division multiple-access (SS-CDMA) techniques to three-dimensional (3-D) stereoscopic video transmission over wireless asynchronous transfer mode (ATM) networks. Three-dimensional visual communications, made through the use of stereoscopic images, are able to achieve total display realism. Such services allow users to share the virtual reality (VR) world without any geographical restrictions. In order to create a 3-D system with two images (left and right) that should be transmitted over a bandlimited mobile channel simultaneously, a cost-effective motion picture experts group (MPEG)-based wavelet multiresolution coding with a joint motion and disparity compensation is developed to reduce a large amount of information contained in the images to meet the low-transmission rate limitation of mobile channels. However, the rapidly variable bit rate (VBR) characteristics of the MPEG-based 3-D videos seems a weakness to the transmission of such videos via a constant bit-rate (CBR) mobile channel. The ATM technique is especially well suited for VBR MPEG-based 3-D video because of its ability to allocate bandwidth on demand to these services. However, since the mobile radio has a limited channel capacity, the overall capacity of the traditional ATM-based SS-CDMA system may not be sufficient to accommodate the MPEG-based 3-D video services requested by the multiple mobile users simultaneously. To tackle this difficulty, a multicode CDMA technique is proposed to provide VBR MPEG-based 3-D video services by varying the number of spreading codes assigned to the 3-D video to meet its dynamic throughput requirement. Powerful forward error correction (FEC) codes are necessary to protect the video data so that it can be successfully transmitted at an acceptable signal power level. Two separate FEC code schemes are applied to the header and payload of an ATM cell containing 3-D video data, respectively. The ATM cell header is protected by a relatively powerful FEC code to ensure correct delivery and low cell loss rate (CLR). On the other hand, the ATM cell payload is encoded for varying degrees of error protection according to the priority of the payload data in 3-D videos. An adaptive FEC code combining scheme is proposed to provide the good protection for payload data with the maximization of its code rate to minimize the extra bandwidth for FEC overhead.

This paper presents a general traffic control framework for Asynchronous Transfer Mode (ATM) networks with its performance evaluation. The proposed traffic control scheme can incorporate all the recently considered ATM service classes including Constant Bit Rate (CBR), real time Variable Bit Rate (rtVBR), non-real time Variable Bit Rate (nrVBR), Available Bit Rate (ABR) and Unspecified Bit Rate (UBR) services. The control is based on a complete buffer partitioning architecture and on the associated buffer scheduling rule with adaptive weighting functions. We present, the formulation of the traffic control as an optimization problem in a 3-dimensional Quality of Service (QoS) state space. A solution approach based on dynamic programming is also suggested. A comprehensive performance evaluation of the method has been performed based on simulations and results are presented with several examples. The QoS dependence on CBR load, VBR load, VBR burstiness, UBR load are investigated and results are demonstrated with explanations.

In view of bandwidth requirements in ATM (asynchronous transfer mode) network, a kind of dynamic bandwidth allocation scheme has been proposed. It solves the problem of low bandwidth utilization ratio caused in VBR (variable bit rate) MPEG (Moving Picture Experts Group) video transmission, the simulation experiment curve indicates that with the increase of already bandwidth value, the average cell loss factor reduces obviously, which satisfies the demand of all connection bandwidth as try as possible. The result indicates that the QoS (quality of service) of this plan has achieved 10-6.

In this paper, we summarise the previous work in the area of modelling variable bit rate (VBR) coded video sources in asynchronous transfer mode (ATM) networks. We verify these models, especially in the area of measuring the quality of their predictions for network performance and the grade of service experienced by a user. In addition to verifying these models, we suggest a new modelling approach of VBR coded video sources. In previous cases, the number of cells generated by the coder for a sequence of video frames are modelled. In the new modelling approach, the number of cells in each type of macroblocks of a frame are modelled. This model is tested by comparing the cell loss rate in simulation of an ATM switch to cell loss rate produced when traces generated by the model were used as source.