5: Percentage of losses for each packet distortion-reduction class (Cat.1=least
significant packets; Cat.8=most significant); (a) Medium-bandwidth case; (b) Low-bandwidth
case. The results correspond to topology T2 of Figure 5.2 and to the video sequence ???Foreman???.
Our results highlight several important issues in network design and infrastructure.
Firstly, it was shown that having frequent feedback via an overlay network about the link
conditions and performing end-to-end optimization with the appropriate utility function
offers significant improvements in the achievable video quality. Indeed, the ???End-to-end???
and ???ETX optimized??? cases outperform the remaining algorithms by 3-5 dB, in all cases
(Table 5.2). Secondly, the importance of choosing a cross-layer distortion-capacity utility
function is highlighted by the fact that both methods outperform the conventional ???Highest
Cross-layer Optimized Video Streaming over Wireless Multi-hop Mesh Networks 124
Bandwidth??? scenario. Moreover, the proposed utility of (12) and the derivation of the
MSDU retransmission limit based on the delay limit for the video transmission ((15)-(17))
appear to be the best choice for video streaming applications.
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