3,637 research outputs found
Media Flow Rate Allocation in Multipath Networks
We address the problem of joint path selection and video source rate allocation in multipath streaming in order to optimize a media specific quality of service. An optimization problem is proposed, which aims at minimizing a video distortion metric based on sequence-dependent parameters, and transmission channel characteristics, for a given network infrastructure.An in-depth analysis of the media distortion evolution allows us to define a low complexity algorithm for an optimal rate allocation in multipath network scenarios. In particular, we show that a greedy allocation of rate along paths with increasing error probability leads to an optimal solution. We argue that a network path shall not be chosen for transmission, unless all other available paths with lower error probability have been chosen. Moreover, the chosen paths should be used at their maximum available end-to-end bandwidth. Simulation results show that the optimal rate allocation carefully trades off total encoding/transmission rate, with the end-to-end transmission error probability and the number of chosen paths. In many cases, the optimal rate allocation provides more than 2
Online multipath convolutional coding for real-time transmission
Most of multipath multimedia streaming proposals use Forward Error Correction
(FEC) approach to protect from packet losses. However, FEC does not sustain
well burst of losses even when packets from a given FEC block are spread over
multiple paths. In this article, we propose an online multipath convolutional
coding for real-time multipath streaming based on an on-the-fly coding scheme
called Tetrys. We evaluate the benefits brought out by this coding scheme
inside an existing FEC multipath load splitting proposal known as Encoded
Multipath Streaming (EMS). We demonstrate that Tetrys consistently outperforms
FEC in both uniform and burst losses with EMS scheme. We also propose a
modification of the standard EMS algorithm that greatly improves the
performance in terms of packet recovery. Finally, we analyze different
spreading policies of the Tetrys redundancy traffic between available paths and
observe that the longer propagation delay path should be preferably used to
carry repair packets.Comment: Online multipath convolutional coding for real-time transmission
(2012
Resilient availability and bandwidth-aware multipath provisioning for media transfer over the internet (Best Paper Award)
Traditional routing in the Internet is best-effort. Path differentiation including multipath routing is a promising technique to be used for meeting QoS requirements of media intensive applications. Since different paths have different characteristics in terms of latency, availability and bandwidth, they offer flexibility in QoS and congestion control. Additionally protection techniques can be used to enhance the reliability of the network.
This paper studies the problem of how to optimally find paths ensuring maximal bandwidth and resiliency of media transfer over the network. In particular, we propose two algorithms to reserve network paths with minimal new resources while increasing the availability of the paths and enabling congestion control. The first algorithm is based on Integer Linear Programming which minimizes the cost of the paths and the used resources. The second one is a heuristic-based algorithm which solves the scalability limitations of the ILP approach. The algorithms ensure resiliency against any single link failure in the network.
The experimental results indicate that using the proposed schemes the connections availability improve significantly and a more balanced load is achieved in the network compared to the shortest path-based approaches
Multipath streaming: fundamental limits and efficient algorithms
We investigate streaming over multiple links. A file is split into small
units called chunks that may be requested on the various links according to
some policy, and received after some random delay. After a start-up time called
pre-buffering time, received chunks are played at a fixed speed. There is
starvation if the chunk to be played has not yet arrived. We provide lower
bounds (fundamental limits) on the starvation probability of any policy. We
further propose simple, order-optimal policies that require no feedback. For
general delay distributions, we provide tractable upper bounds for the
starvation probability of the proposed policies, allowing to select the
pre-buffering time appropriately. We specialize our results to: (i) links that
employ CSMA or opportunistic scheduling at the packet level, (ii) links shared
with a primary user (iii) links that use fair rate sharing at the flow level.
We consider a generic model so that our results give insight into the design
and performance of media streaming over (a) wired networks with several paths
between the source and destination, (b) wireless networks featuring spectrum
aggregation and (c) multi-homed wireless networks.Comment: 24 page
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