QoS-Aware A-MPDU Retransmission Scheme for 802.11n/ac/ad WLANS

The aggregate MAC protocol data unit (A-MPDU) is one of the pivotal aggregation schemes, defined by the IEEE 802.11n/ac/ad, to improve the transmission efficiency of MAC layer. However, A-MPDU scheme is not efficient in error-prone conditions due to its decrease in retransmission aggregation levels. To overcome this problem, a novel QoS-aware A-MPDU retransmission scheme is proposed in this letter. The scheme fully exploits the aggregation level while considering the strict end-to-end delay requirements by QoS applications. In the proposed scheme, the aggregation levels of the retransmitted A-MPDU frames are decided based on the aggregation sliding window strategy, and the expected delay of the proposed scheme and the traditional scheme, respectively, which is calculated through theoretical analysis. The effectiveness of the scheme is demonstrated via experimental evaluation using ns-3.