6 research outputs found

    A FRAME RESIST JAMMING GUIDANCE FOR VIDEO TRAFFIC IN WIRELESS MULTIHOP NETWORKS

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    A large-different research was present on routing calculations for wireless random with meshes systems. Previous creates routing meant for video communications will spotlight on multiple description coding. The schemes of multipath routing are believed to be to obtain greater quality of video transfer. Inside our work we consider wireless network in which the application flows includes video traffic and introduce an analytical structure that captures impact of routing on finish-to-finish video features regarding distortion. The expansion will facilitate computation of routes that are best regarding achieving of least distortion. To think about growth of the whole process of video frame loss, analytical structure recognizes and, assesses impact of wireless network above video distortion. The recommended system will grant us to make a routing policy meant for minimizing distortion that's which we goal a procedure for routing video traffic. Our proposal is video quality of user-perceived is considerably enhanced by means of comprising application needs, especially video distortion that's possessed a flow. Our physiques of routing are enhanced for moving videos above wireless systems by means of minimum video distortion

    A PERVERSION-RESISTANT ROUTING FOR VIDEO DELAY IN WIRELESS NETWORKS

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    From the user perspective, reducing the amount of video distortion is crucial. Popular link-quality-based routing metrics don't take into account dependence over the links of the path consequently, they are able to cause video flows to converge onto a couple of pathways and, thus, cause high video distortion. Traditional routing metrics created for wireless systems are application-agnostic. Within this paper, we think about a wireless network in which the application flows contain video traffic. Particularly, the various amounts of encoding make reference to, either information encoded individually, within the situation of I-frames, or encoding in accordance with the data encoded within other frames, out of the box the situation for P- and B-frames. We discover via simulations and test bed experiments our protocol is efficient in lessening video distortion and minimizing the consumer experience degradation. To take into account the evolution from the video frame loss process, we construct an analytical framework to, first, understand and, second, measure the impact from the wireless network on video distortion. Because of the complexity from the optimization problem, an inherited-formula-based heuristic approach can be used to compute the routes. Our approach differs not just in route we model video distortion, but additionally on the truth that we concentrate on LC that is popular in programs today.  The framework enables us to formulate a routing insurance policy for minimizing distortion, according to which we design a protocol for routing video traffic

    Impact of network dynamics on user\u27s video quality : analytical framework and QoS provision

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    Routing-aware multiple description video coding over mobile ad-hoc networks

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    Abstract-Supporting video transmission over error-prone mobile ad-hoc networks is becoming increasingly important as these networks become more widely deployed. We propose a routingaware multiple description video coding approach to support video transmission over mobile ad-hoc networks with multiple path transport. We build a statistical model to estimate the packet loss probability of each packet transmitted over the network based on the standard ad-hoc routing messages and network parameters. We then estimate the frame loss probability and dynamically select reference frames in order to alleviate error propagation caused by the packet losses. We conduct experiments using the QualNet simulator that accounts for node mobility, channel properties, MAC operation, multipath routing, and traffic type. The results demonstrate that our proposed method provides 0.7-2.3 dB gains in PSNR for different video sequences under different network settings and guarantees better video quality for a selectably high number of users of the network. Furthermore, we examine the estimation accuracy of our proposed estimation model and show that our model works effectively under various network settings

    Provision Quality-of-Service Controlled Content Distribution in Vehicular Ad Hoc Networks

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    By equipping vehicles with the on-board wireless facility, the newly emerged vehicular networking targets to provision the broadband serves to vehicles. As such, a variety of novel and exciting applications can be provided to vehicular users to enhance their road safety and travel comfort, and finally raise a complete change to their on-road life. As the content distribution and media/video streaming, such as Youtube, Netflix, nowadays have become the most popular Internet applications, to enable the efficient content distribution and audio/video streaming services is thus of the paramount importance to the success of the vehicular networking. This, however, is fraught with fundamental challenges due to the distinguished natures of vehicular networking. On one hand, the vehicular communication is challenged by the spotty and volatile wireless connections caused by the high mobility of vehicles. This makes the download performance of connections very unstable and dramatically change over time, which directly threats to the on-top media applications. On the other hand, a vehicular network typically involves an extremely large-scale node population (e.g., hundreds or thousandths of vehicles in a region) with intense spatial and temporal variations across the network geometry at different times. This dictates any designs to be scalable and fully distributed which should not only be resilient to the network dynamics, but also provide the guaranteed quality-of-service (QoS) to users. The purpose of this dissertation is to address the challenges of the vehicular networking imposed by its intrinsic dynamic and large-scale natures, and build the efficient, scalable and, more importantly, practical systems to enable the cost-effective and QoS guaranteed content distribution and media streaming services to vehicular users. Note that to effective- ly deliver the content from the remote Internet to in-motion vehicles, it typically involves three parts as: 1.) an infrastructure grid of gateways which behave as the data depots or injection points of Internet contents and services to vehicles, 2.) protocol at gateways which schedules the bandwidth resource at gateways and coordinates the parallel transmissions to different vehicles, and 3.) the end-system control mechanism at receivers which adapts the receiver’s content download/playback strategy based on the available network throughput to provide users with the desired service experience. With above three parts in mind, the entire research work in this dissertation casts a systematic view to address each part in one topic with: 1.) design of large-scale cost-effective content distribution infrastructure, 2.) MAC (media access control) performance evaluation and channel time scheduling, and 3.) receiver adaptation and adaptive playout in dynamic download environment. In specific, in the first topic, we propose a practical solution to form a large-scale and cost-effective content distribution infrastructure in the city. We argue that a large-scale infrastructure with the dedicated resources, including storage, computing and communication capacity, is necessary for the vehicular network to become an alternative of 3G/4G cellular network as the dominating approach of ubiquitous content distribution and data services to vehicles. On addressing this issue, we propose a fully distributed scheme to form a large-scale infrastructure by the contributions of individual entities in the city, such as grocery stores, movie theaters, etc. That is to say, the installation and maintenance costs are shared by many individuals. In this topic, we explain the design rationale on how to motivate individuals to contribute, and specify the detailed design of the system, which is embodied with distributed protocols and performance evaluation. The second topic investigates on the MAC throughput performance of the vehicle-to- infrastructure (V2I) communications when vehicles drive through RSUs, namely drive-thru Internet. Note that with a large-scale population of fast-motion nodes contending the chan- nel for transmissions, the MAC performance determines the achievable nodal throughput and is crucial to the on-top applications. In this topic, using a simple yet accurate Marko- vian model, we first show the impacts of mobility (characterized by node velocity and moving directions) on the nodal and system throughput performance, respectively. Based on this analysis, we then propose three enhancement schemes to timely adjust the MAC parameters in tune with the vehicle mobility to achieve the maximal the system throughput. The last topic investigates on the end-system design to deliver the user desired media streaming services in the vehicular environment. In specific, the vehicular communications are notoriously known for the intermittent connectivity and dramatically varying throughput. Video streaming on top of vehicular networks therefore inevitably suffers from the severe network dynamics, resulting in the frequent jerkiness or even freezing video playback. To address this issue, an analytical model is first developed to unveil the impacts of network dynamics on the resultant video performance to users in terms of video start-up delay and smoothness of playback. Based on the analysis, the adaptive playout buffer mechanism is developed to adapt the video playback strategy at receivers towards the user-defined video quality. The proposals developed in the three topics are validated with the extensive and high fidelity simulations. We believe that our analysis developed in the dissertation can provide insightful lights on understanding the fundamental performance of the vehicular content distribution networks from the aspects of session-level download performance in urban vehicular networks (topic 1), MAC throughput performance (topic 2), and user perceived media quality (topic 3). The protocols developed in the three topics, respectively, offer practical and efficient solutions to build and optimize the vehicular content distribution networks

    Diversity and Reliability in Erasure Networks: Rate Allocation, Coding, and Routing

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    Recently, erasure networks have received significant attention in the literature as they are used to model both wireless and wireline packet-switched networks. Many packet-switched data networks like wireless mesh networks, the Internet, and Peer-to-peer networks can be modeled as erasure networks. In any erasure network, path diversity works by setting up multiple parallel connections between the end points using the topological path redundancy of the network. Our analysis of diversity over erasure networks studies the problem of rate allocation (RA) across multiple independent paths, coding over erasure channels, and the trade-off between rate and diversity gain in three consecutive chapters. In the chapter 2, Forward Error Correction (FEC) is applied across multiple independent paths to enhance the end-to-end reliability. We prove that the probability of irrecoverable loss (P_E) decays exponentially with the number of paths. Furthermore, the RA problem across independent paths is studied. Our objective is to find the optimal RA, i.e. the allocation which minimizes P_E. Using memoization technique, a heuristic suboptimal algorithm with polynomial runtime is proposed for RA over a finite number of paths. This algorithm converges to the asymptotically optimal RA when the number of paths is large. For practical number of paths, the simulation results demonstrate the close-to-optimal performance of the proposed algorithm. Chapter 3 addresses the problem of lower-bounding the probability of error (PE) for any block code over an input-independent channel. We derive a lower-bound on PE for a general input-independent channel and find the necessary and sufficient condition to meet this bound with equality. The rest of this chapter applies this lower-bound to three special input-independent channels: erasure channel, super-symmetric Discrete Memoryless Channel (DMC), and q-ary symmetric DMC. It is proved that Maximum Distance Separable (MDS) codes achieve the minimum probability of error over any erasure channel (with or without memory). Chapter 4 addresses a fundamental trade-off between rate and diversity gain of an end-to-end connection in erasure networks. We prove that there exist general erasure networks for which any conventional routing strategy fails to achieve the optimum diversity-rate trade-off. However, for any general erasure graph, we show that there exists a linear network coding strategy which achieves the optimum diversity-rate trade-off. Unlike the previous works which suggest the potential benefit of linear network coding in the error-free multicast scenario (in terms of the achievable rate), our result demonstrates the benefit of linear network coding in the erasure single-source single-destination scenario (in terms of the diversity gain)
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