An Enhanced Link Layer Retransmission Scheme for IEEE 802.11

Abstract

In the IEEE 802.11 WLAN standard, a positive acknowledgement informs the sender of successful arrivals of data frames. However unacknowledged frames could result from either unsuccessful delivery of data frames or losses of positive ACK frames. Therefore the sender will simply retransmit the unacknowledged data frame, which may cause redundant retransmission in case of positive ACK frame losses. In this paper we propose an enhanced retransmission scheme, called Dynamically Adaptive Retransmission (DAR), which uses modified frames containing additional information on transmission status of unacknowledged frames. Based on that information, the sender is able to dynamically determine whether to retransmit or not. Experiments and analysis show that the proposed scheme can efficiently reduces redundant retransmission by clearly differentiating ACK frame losses from data frame losses.