2030101030012 ; 電機工程學系 ; In this paper, we propose a content-aware retry limit adaptation scheme for video streaming over IEEE 802.11 wireless LANs (WLANs). Video packets of different importance are unequally protected with different retry limits at the MAC layer. The loss impact of each packet is estimated to guide the selection of its retry limit. More retry numbers are allocated to packets of higher loss impact to achieve unequal error protection. Our scheme also analyzes the backoff time for each retry and then takes into account the estimated backoff time for retransmission scheduling. Experimental results show that our adaptation scheme can effectively mitigate the error propagation due to packet loss and assure the on-time arrival of packets for presentation, thereby improving video quality significantly.