A multipath video streaming testbed for ad hoc networks

Enabling video transport over ad hoc networks is more challenging than over other wireless networks. The wireless links in an ad hoc network are highly error prone and can go down frequently because of node mobility, interference, channel fading, and the lack of infrastructure. However, the mesh topology of ad hoc networks implies the existence of multiple paths between two nodes. Indeed, multipath transport provides an extra degree of freedom in designing error resilient video coding and transport schemes. In our previous work, we propose schemes combining multistream coding with multipath transport, to show that path diversity provides an effective means to combat transmission error in ad hoc networks. In this paper, we report the implementation of a multiple path video streaming testbed using notebook computers and IEEE 802.11b cards, to validate the viability and performance advantages of these schemes. We implemented a layered coding with selective ARQ scheme and a multiple description motion compensation coding scheme in the testbed. The experimental results show that video transport is viable in ad hoc networks given careful cross-layer design. Combining multistream coding with MPT improves video quality, as compared to traditional schemes where a single path is used.