Mitigating the impact of packet reordering to maximize performance of multimedia applications

We propose a solution to mitigate the performance degradation and corresponding Quality of Experience (QoE) reduction caused by packet reordering for multimedia applications which utilise unreliable transport protocols like the Datagram Congestion Control Protocol (DCCP). We analytically derive the optimum buffer size based on the applications data rate and the maximum delay tolerated by the multimedia application. We propose a dynamically adjustable buffer in the transport protocol receiver which uses this optimum buffer size. We demonstrate, via simulation results, that our solution reduces the packet loss rate, increases the perceived bandwidth and does not increase jitter in the received applications packets while still being within the application's delay limits, therefore resulting in an increased QoE of multimedia applications

Real-time Admission Control Algorithms with Delay and Loss Guarantees in ATM Networks

A multimedia ATM network is shared by media streams with different performance requirements. For media streams such as file transfers, the preservation of bursts and the provision of guarantees for loss probability at the burst level is of primary importance, while, for media streams such as voice, loss guarantees at the cell level are sufficient. Continuous media have stringent delay jitter requirements. Finally, some applications require loss-free transmission. In this paper, the first complete traffic management scheme for multimedia ATM networks is introduced. The traffic management scheme supports four different classes of traffic, each of which has different performance requirements expressed in terms of delay jitter guarantees and cell or burst level loss guarantees. Its running time specification as well as its real time admission control algorithms are completely specified

New contention resolution schemes for WiMAX

Abstract—The use of Broadband Wireless Access (BWA) technology is increasing due to the use of Internet and multimedia applications with strict requirements of end–to–end delay and jitter, through wireless devices. The IEEE 802.16 standard, which defines the physical (PHY) and the medium access control (MAC) layers, is one of the BWA standards. Its MAC layer is centralized basis, where the Base Station (BS) is responsible for assigning the needed bandwidth for each Subscriber Station (SS), which requests bandwidth competing between all of them. The standard defines a contention resolution process to resolve the potential occurrence of collisions during the requesting process. In this paper, we propose to modify the contention resolution process to improve the network performance, including end–to–end delay and throughput

The perceptual and attentive impact of delay and jitter in multimedia delivery

In this paper we present the results of a study that examines the user’s perception—understood as both information assimilation and subjective satisfaction—of multimedia quality, when impacted by varying network-level parameters (delay and jitter). In addition, we integrate eye-tracking assessment to provide a more complete understanding of user perception of multimedia quality. Results show that delay and jitter significantly affect user satisfaction; variation in video eye path when either no single/obvious point of focus exists or when the point of attention changes dramatically. Lastly, results showed that content variation significantly affected user satisfaction, as well as user information assimilation

Defining user perception of distributed multimedia quality

This article presents the results of a study that explored the human side of the multimedia experience. We propose a model that assesses quality variation from three distinct levels: the network, the media and the content levels; and from two views: the technical and the user perspective. By facilitating parameter variation at each of the quality levels and from each of the perspectives, we were able to examine their impact on user quality perception. Results show that a significant reduction in frame rate does not proportionally reduce the user's understanding of the presentation independent of technical parameters, that multimedia content type significantly impacts user information assimilation, user level of enjoyment, and user perception of quality, and that the device display type impacts user information assimilation and user perception of quality. Finally, to ensure the transfer of information, low-level abstraction (network-level) parameters, such as delay and jitter, should be adapted; to maintain the user's level of enjoyment, high-level abstraction quality parameters (content-level), such as the appropriate use of display screens, should be adapted

A Utility-based QoS Model for Emerging Multimedia Applications

Existing network QoS models do not sufficiently reflect the challenges faced by high-throughput, always-on, inelastic multimedia applications. In this paper, a utility-based QoS model is proposed as a user layer extension to existing communication QoS models to better assess the requirements of multimedia applications and manage the QoS provisioning of multimedia flows. Network impairment utility functions are derived from user experiments and combined to application utility functions to evaluate the application quality. Simulation is used to demonstrate the validity of the proposed QoS model

Perceptual multimedia quality: Implications of an empirical study

Copyright @ 2005 HCI InternationalIf commercial multimedia development continues to ignore the user-perspective in preference of other factors, i.e. user fascination (i.e. the latest gimmick), then companies ultimately risk alienating the customer. Moreover, by ignoring the user-perspective, future distributed multimedia systems risk ignoring accessibility issues, by excluding access for users with abnormal perceptual requirements. This paper presents an extensive examination of distributed multimedia quality. We define a model that considers multimedia quality from three distinct levels: the network, the media- and the content-levels; and two views: the technical- and the user-perspective. By manipulating both technical and user-perspective parameters, we examine the impact on quality perception at the three quality levels identified. Results show that: a significant reduction in frame rate does not proportionally reduce the user's understanding of the presentation, independent of technical parameters; the type of video clip significantly impacts user information assimilation, user level of enjoyment and user perception of quality; the display type impacts user information assimilation and user perception of quality. Finally, to ensure transfer of informational content, network parameter variation should be adapted; to maintain user enjoyment, video content variation should be adapted

Dynamic bandwidth allocation with SLA awareness for QoS in ethernet passive optical networks

Quality-of-service (QoS) support in Ethernet passive optical networks is a crucial concern. We propose a new dynamic bandwidth allocation (DBA) algorithm for service differentiation that meets the service-level agreements (SLAs) of the users. The proposed delay-aware (DA) online DBA algorithm provides constant and predictable average packet delay and reduced delay variation for the high-and medium-priority traffic while keeping the packet loss rate under check. We prove the effectiveness of the proposed algorithm by exhaustive simulations