Distortion-resilient routing for video flows in wireless multi-hop networks

Traditional routing metrics designed for wireless networks are application agnostic. In this paper, we consider a wireless network where the application flows consist of video traffic. From a user-perspective, reducing the level of video distortion is critical. We ask the question "Should the routing policies change if the end-to-end video distortion is to be minimized?" Popular link-quality based routing metrics (such as ETX) do not account for dependence (in terms of congestion) across the links of a path; as a result, they can cause video flows to converge onto a few paths and thus, cause high video distortion. To account for the evolution of the video frame loss process we construct an analytical framework to first, understand and second, assess the impact of the wireless network on video distortion. The framework allows us to formulate a routing policy for minimizing distortion, based on which we design a protocol for routing video traffic. We find via simulations and testbed experiments that our protocol is efficient in reducing video distortion and minimizing the user experience degradation. Specifically, our protocol reduces the distortion by 20% over traditional methods, which significantly improves the video quality perceived by a user.