No abstract

Abstract-With today's widespread deployment of wireless technologies, it is often the case that a single communication device can select from a variety of access networks. At the same time, there is an ongoing trend towards integration of multiple network interfaces into end-hosts, such as cell phones with HSDPA, Bluetooth and WLAN. By using multiple Internet connections concurrently, network applications can benefit from aggregated bandwidth and increased fault tolerance. However, the heterogeneity of wireless environments introduce challenges with respect to implementation, deployment, and protocol compatibility. Variable link characteristics cause reordering when sending IP packets of the same flow over multiple paths. This paper introduces a multilink proxy that is able to transparently stripe traffic destined for multihomed clients. Operating on the network layer, the proxy uses path monitoring statistics to adapt to changes in throughput and latency. Experimental results obtained from a proof-of-concept implementation verify that our approach is able to fully aggregate the throughput of heterogeneous downlink streams, even if the path characteristics change over time. In addition, our novel method of equalizing delays by buffering packets on the proxy significantly reduces IP packet reordering and the buffer requirements of clients.

A well known challenge with mobile video streaming is fluctuating bandwidth. As the client devices move in and out of network coverage areas, the users may experience varying signal strengths, competition for the available resources and periods of network outage. These conditions have a significant effect on video quality.In this paper, we present a video streaming solution for roaming clients that is able to compensate for the effects of oscillating bandwidth through bandwidth prediction and video quality scheduling. We combine our existing adaptive segmented HTTP streaming system with 1) an application layer framework for creating transparent multi-link applications, and 2) a location-based QoS information system containing GPS coordinates and accompanying bandwidth measurements, populated through crowd-sourcing. Additionally, we use real-time traffic information to improve the prediction by, for example, estimating the length of a commute route. To evaluate our prototype, we performed realworld experiments using a popular tram route in Oslo, Norway. The client connected to multiple networks, and the results show that our solution increases the perceived video quality significantly. Also, we used simulations to evaluate the potential of aggregating bandwidth along the route.

No abstract