دانلود رایگان مقاله جریان ویدئوی پروتکل کنترل انتقال و شبکه های سیار

Abstract

The rise in popularity of TCP-based video streaming in recent years is unbroken. These streaming services not just operate on wired access lines but more and more specifically target users of mobile networks as well. Yet it still remains difficult to evaluate the performance of such streaming approaches in mobile networks. This is especially critical as mobile networks exhibit much more potential for undesirable interactions between the network protocol layers and control plane properties on one side and the protocols and strategies of the application layer on the other side, ultimately resulting in scenarios with bad QoE for video streaming. This paper aims to rectify this lack of knowledge and understanding in a multi-pronged approach as follows: The first contribution provides an easy means to investigate such interactions with a streaming simulation framework built on ns-3. In a second contribution three exemplary scenarios within this framework are investigated in order to uncover the nature of such interactions. The final undertaking attempts to unravel the issues of the mobility scenario using context information. Such information can be collected through crowdsensing and collaboratively processed in a Big Data approach. This results in a tailor-made analytical solution through the formulation of a Mixed Integer Linear Program (MILP) that can prevent video stalling in this particular scenario.

8. Conclusions and future work

TCP-based video streaming and mobile networks can interact in the most interesting ways as this work aimed to demonstrate. These kinds of interactions are not easy to uncover due to the sheer complexity of mobile networks and the lack of tools for proper investigations in the past. While the former issue can only be unraveled through strenuous, time-intensive research, work conducted in this paper can help improve the situation around the latter issue. The mobile streaming examination framework compiled here can provide an initial foundation for further interaction evaluations. The LTE models currently implemented in free network simulators are finally mature enough to provide some insights into the performance of mobile streaming applications, albeit with the limitation of the missing control plane signaling interactions and load. The three initial experimental scenarios, that were set up using this framework, already showed some pitfalls in the way streaming transmission strategies can be set up, and a surprising interaction of the TCP/IP stack with LTE’s mobile network design. It can therefore be concluded that appropriate measures need to be taken to ensure a consistent streaming quality. Amongst others, this involves, for example, a careful choice of the playback strategy and its parameters as well as thresholds. The additional analytical investigation of scenarios that can occur during device mobility, namely the intermittent loss of the radio connection and the subsequent chance of stalling, also demonstrated the positive impact the monitoring of context factors and context-aware streaming strategies can have. Both the acquisition of context information as well as the successive prediction of blind spot events can be tackled by a mixture of cross-layer information exchange, crowdsourcing, and Big Data and are an endeavor for future investigations. All in all, it can be said that the knowledge of interactions between mobile nets and video streaming is still in its infancy. Further research on this topic and on remedies for specific interactions, like context awareness, shows much prospect.