To cope with the time-varying network conditions, various error-protection and channel adaptation strategies have been
proposed at different layers of the protocol stack. However, these cross-layer strategies can be efficiently optimized only
if they act on accurate information about the network conditions and hence, are able to timely adapt to network changes.
We analyze the impact of such information feedback on the video quality performances of the collaborative multimedia
users sharing the same multi-hop wireless infrastructure. Based on the information feedback, we can estimate the risk that
packets from different priority and deadline classes will not arrive at their destination before their decoding deadline.
Subsequently, cross-layer optimization strategies such as packet scheduling, retransmission (due to transmission error)
limit are adapted to jointly consider the estimated risk as well as the impact in terms of distortion of not receiving
different priority packets. Our results quantify the risk estimation and its benefit in different network conditions and for
various video applications with different delay constraints.
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