1,721,020 research outputs found
Video transport optimization techniques design and evaluation for next generation cellular networks
Full text linkVideo is foreseen to be the dominant type of data traffic in the Internet. This vision is supported by a number of studies which forecast that video traffic will drastically increase in the following years, surpassing Peer-to-Peer traffic in volume already in the current year.
Current infrastructures are not prepared to deal with this traffic increase. The current Internet, and in particular the mobile Internet, was not designed with video requirements in mind and, as a consequence, its architecture is very inefficient for handling this volume of video traffic. When a large part of traffic is associated to multimedia entertainment, most of the mobile infrastructure is used in a very inefficient way to provide such a simple service, thereby saturating the whole cellular network, and leading to perceived quality levels that are not adequate to support widespread end user acceptance.
The main goal of the research activity in this thesis is to evolve the mobile Internet architecture for efficient video traffic support. As video is expected to represent the majority of the traffic, the future architecture should efficiently support the requirements of this data type, and specific enhancements for video should be introduced at all layers of the protocol stack where needed. These enhancements need to cater for improved quality of experience, improved reliability in a mobile world (anywhere, anytime), lower exploitation cost, and increased flexibility.
In this thesis a set of video delivery mechanisms are designed to optimize the video transmission at different layers of the protocol stack and at different levels of the cellular network. Upon the architectural choices, resource allocation schemes are implemented to support a range of video applications, which cover video broadcast/multicast streaming, video on demand, real-time streaming, video progressive download and video upstreaming.
By means of simulation, the benefits of the designed mechanisms in terms of perceived video quality and network resource saving are shown and compared to existing solutions. Furthermore, selected modules are implemented in a real testbed and some experimental results are provided to support the development of such transport mechanisms in practice
Opportunistic scheduling and rate adaptation for scalable broadcast video streaming
No full textIn this work we propose an adaptation framework where video packets are opportunistically scheduled for broadcast/multicast media streaming applications. The scheduling mechanism operates based on the average and instantaneous user distributions and radio link channel quality, information obtained through the cellular uplink channel. In our framework we use H.264 Scalable Video Coding (SVC) to generate multiple independent streams or scalable sub-streams, further split into video packets, which are opportunistically scheduled with the goal of maximizing the average quality of service for the end user. Based on the design of our delivery system, we finally foresee practical implementations of efficient scheduling algorithms for broadcast video delivery over next generation cellular networks
Robust opportunistic broadcast scheduling for scalable video streaming
No full textIn this paper we design a robust opportunistic scheduler to be implemented at the base station in a cellular network for broadcast media streaming applications. The scheduling mechanism operates based on information on both the average and the instantaneous user distributions, and on radio link channel quality, obtained through the cellular uplink channel. Video streams are encoded into multiple scalable video layers, that are split into video packets opportunistically scheduled at the base station with the goal of minimizing the wireless resource usage while keeping the overall target Quality of Service (QoS) in the cell. We finally discuss potential extensions of this framework to more sophisticated scheduling solutions for broadcast video delivery over next generation cellular networks
Performance evaluation in ns-3 of a video delivery framework for next generation cellular networks
No full textVideo mobile applications can be served via multiple delivery paths from the video server to the end user, thus delivering different video qualities. Throughput and delay highly depend on the video paths available in the core network and on the availability of wireless access technologies in the last hop. We consider a set of characteristics of the whole video delivery chain to univocally identify each available path and we develop a framework for the selection of the best video path in terms of throughput and packet delivery delay. We further extend the framework, implementing at the access points a tunable traffic shaping mechanism to decrease the delivery delay while maintaining the number of packets delivered. We evaluate our framework by means of simulation in ns-3, an event-based network simulator able to accurately model the Long Term Evolution (LTE) core and access networks
Scalable video broadcast in cellular networks: impact on QoS and network resources
No full textBroadcast video streaming represents an important service which will be provided by 4G networks. The current video compression in use, the H.264/AVC (Advance Video Coding), is capable of providing good video quality at substantially lower bit rates than previous video compression standards. The scalable extension of AVC, SVC (Scalable Video Coding), enables a source to transmit a video composed of multiple quality, temporal and spatial sub-streams. The flexibility offered by SVC is appealing for broadcast streaming services, where heterogeneous devices and sets of users are supported. SVC combined with MAC scheduling and the flexibility offered by different modulation and coding schemes provide a novel solution for broadcast streaming services. In this paper, we propose a generic optimization framework to evaluate the performance of the current standard used for streaming services, AVC, and its scalable extension SVC, in terms of wireless utilization, storage requirements and perceived video quality for a single-site transmission scenario. This framework can be implemented on mobile multimedia broadcasting systems, such as ISDB-Tmm [1]. ISDB-Tmm currently considers AVC as video codec, but can be extended to support SVC as well. Selected simulations show the benefits provided by using SVC for broadcast video streaming in a single cell network making use of a flexible MAC layer scheduling. Our study is then extended to a multi-cell network, discussing the issues related to practical deployments
A Fast Rate-Adaptation Algorithm for Robust Wireless Scalable Streaming Applications
No full textIn this paper we consider a server sending a scalable video stream over a wireless channel to an end-user. We design a fast rate adaptation algorithm which chooses the right transmission policy (video data and associated unequal error protection) based on channel feedback. Our algorithm can be easily implemented as a smart scheduling module at the server side, which adapts its packet selection rules based on the total available channel rate and losses experienced by the end-user. Our simulation results show the good performance of our algorithm compared to the optimal transmission policy, for a wide range of channel conditions. We also identify scenarios that fully benefit from scalable encoding augmented by unequal error protection, compared to traditional bitstream-switching methods based on single stream transmission protected by FEC
Reliable broadcast streaming over 802.11 WLANs with minimum channel usage
No full textIn this paper we investigate the interaction of channel code and modulation (i.e., the bitrate) of wireless transmissions and application layer forward error correction in the context of media streaming. To this end, we design a multimedia delivery protocol based on systematic network coding with partial feedback for reliable broadcast streaming over WLANs. Differently from other work, our approach takes into account the trade-off between (i) exploiting feedback-based encoded retransmissions at the multimedia broadcast source to compensate for the lack of MAC-layer error recovery mechanisms, and (ii) the efficient use of the wireless channel resources as given by the selected modulation scheme and the amount of feedback messages. The proposed protocol is tailored to the delay/packet loss rate demands of multimedia traffic and uses a combination of modulation rate and a forward error correction overhead which jointly leads to a minimal channel usage
Analyzing the combination of different approaches for video transport optimization for next generation cellular networks
No full textVarious technologies for optimizing video delivery in cellular networks have been presented in the past. QoE-based transport optimizations attempt to look for optimal solutions to provide the best overall user experience for a group of users to leverage constrained network bandwidth. However, the design of these optimizations varies widely. An attractive idea is to deploy these optimizations together and expect more gains. In this article, we describe the interworking of several optimization approaches to analyze the feasibility of one single framework combining different approaches. We provide a first design of the joint framework that best leverages the advantage of each optimization approach
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