Abstract:
Traditional error recovery schemes such as automatic repeat request (ARQ) and
incremental forward error correction (FEC) rely on immediate retransmissions to deal with
transmission errors. Such an approach leads to substantial energy drain and notable
performance degradation in case of multimedia communications over wireless networks
especially when the probability of data error is high. Moreover, retransmissions negatively
impact the performance of other mobile nodes due to the nature of resource sharing in
wireless environments. In this thesis, an energy-aware retransmission scheme for
multimedia distribution over wireless networks is designed, implemented, and evaluated in
different realistic network scenarios. The proposed scheme adapts the retransmission rate
based on the predicted channel conditions in a way that keeps the quality of service metrics
within the desired range. Performance results using ns2 simulations demonstrate reduction of up to 50% in terms of energy consumption while maintaining the target quality
constraints. Results also show that the proposed scheme outperforms the default WLAN
medium access control (MAC) protocol in terms of packet delay that is an important
metric for real-time multimedia applications.
