  The explosive demand of on-line video from smart mobile devices poses
unprecedented challenges to delivering high quality of experience (QoE) over
wireless networks. Streaming high-definition video with low delay is difficult
mainly due to (i) the stochastic nature of wireless channels and (ii) the
fluctuating videos bit rate. To address this, we propose a novel delay-aware
fountain coding (DAF) technique that integrates channel coding and video
coding. In this paper, we reveal that the fluctuation of video bit rate can
also be exploited to further improve fountain codes for wireless video
streaming. Specifically, we develop two coding techniques: the time-based
sliding window and the optimal window-wise sampling strategy. By adaptively
selecting the window length and optimally adjusting the sampling pattern
according to the ongoing video bit rate, the proposed schemes deliver
significantly higher video quality than existing schemes, with low delay and
constant data rate. To validate our design, we implement the protocols of DAF,
DAF-L (a low-complexity version) and the existing delay-aware video streaming
schemes by streaming H.264/AVC standard videos over an 802.11b network on CORE
emulation platform. The results show that the decoding ratio of our scheme is
15% to 100% higher than the state of the art techniques.
