Performance Evaluation of Concurrent Multipath Video Streaming in Multihomed Mobile Networks

High-quality real-time video streaming to users in mobile networks is challenging due to the dynamically changing nature of the network paths, particularly the limited bandwidth and varying end-to-end delay. In this paper, we empirically investigate the performance of multipath streaming in the context of multihomed mobile networks. Existing schemes that make use of the aggregated bandwidth of multiple paths can overcome bandwidth limitations on a single path but suffer an efficiency penalty caused by retransmission of lost packets in reliable transport schemes or path switching overheads in unreliable transport schemes. This work focuses on the evaluation of schemes to permit concurrent use of multiple paths to deliver video streams. A comprehensive streaming framework for concurrent multipath video streaming is proposed and experimentally evaluated, using current state-of-the-art H.264 Scalable Video Coding (H.264/SVC) and the next generation High Efficiency Video Coding (HEVC) standards. It provides a valuable insight into the benefit of using such schemes in conjunction with encoder specific packet prioritisation mechanisms for quality-aware packet scheduling and scalable streaming. The remaining obstacles to deployment of concurrent multipath schemes are identified, and the challenges in realising HEVC based concurrent multipath streaming are highlighted.

ASYMPTOTICALLY OPTIMAL LOAD DISTRIBUTION FOR MULTIPATH STREAMING UNDER FEC

Multipath streaming protocols have recently attracted much attention because they provide an effective means to provide high-quality streaming over the Internet. Most existing multipath streaming schemes also apply forward error correction (FEC) encoding in the stream so as to provide high-quality streaming of prestored or live media content. However, the problem of how to intelligently split the FEC-encoded stream among multiple available paths has not been fully addressed. Most previous work focused on protocol design or heuristic-based engineering approaches. Exact analysis turns out to be hard, as it involves heavy combinatorics computation. In this article, we develop an analytical model and use asymptotic analysis to address the problem of optimal load distribution. Using asymptotic approximations, we propose a closed-form formulation for the optimal load distribution problem. We then develop interesting properties of the optimal solution based on majorization, interchanging argument, and optimization techniques. These results are surprisingly simple yet insightful. We further demonstrate through simulation that our asymptotic solution works quite well in practice.

Multipath Video Streaming Using GRA Network Ordering Algorithm without Rank Inconsistency

Simultaneous connection to several networks through multiple interfaces is possible with today’s mobile terminals. In order to efficiently utilize the interfaces’ capabilities and increase the quality of the streamed video, multipath streaming can be used. Resource intensive applications can deliver high bitrate streams over multiple paths bycumulating the available bandwidth of the different subpaths. In this paper we propose a multipath streaming method that chooses a set of paths maximizing the overall quality at the client. While the available paths have different bandwidth, delay and loss probability constrains, the packet distributor must take the video packet importance and the dependencies between packets into account. In order to efficiently distributethe packets, the link must be ordered based on the network attributes. Grey Relational Analysis (GRA) is a promising algorithmic approach that can realize dynamic interface ordering with multiple alternatives (interfaces) and attributes (network parameters). However similarly to some other decision methods, GRA also suffers from rank reversal phenomenon. Transmitting the reference video frames on the most reliable links will decrease the loss probability of important data packets and increase the measured video quality. The change of link order can lead to frequent handovers causing the degradation of the observed video quality.