Enhancing Performance via Block ACK Window Adaptation in Aggregation-Enabled Future WLANs

The IEEE 802.11 wireless local area networks (WLANs) utilize the aggregated MAC protocol data unit (A-MPDU) mechanism to improve transmission efficiency at the MAC layer. However, packet errors caused by channel noise significantly disrupt the functioning of the sliding block acknowledgment window (BAW) during A-MPDU aggregation, leading to reduced aggregation levels and degraded network performance. To address this issue, we propose enlarging the BAW size to enhance frame aggregation, which is particularly suitable for newer standards such as IEEE 802.11ax and 802.11be. Meanwhile, we develop a novel three-dimensional Markov analytical model that accurately captures frame aggregation behavior under arbitrary BAW sizes. Based on the derived distribution of aggregation levels, we further present analytical models for estimating throughput and access delay in both distributed coordination function (DCF) and uplink orthogonal frequency division multiple access (OFDMA)-based random access (UORA) mechanisms. Additionally, we propose an optimal BAW size selection algorithm to meet specified performance targets with minimal overhead. Simulation results validate the accuracy of the proposed models and demonstrate throughput improvements of up to 21.95% and 53.06% in DCF and UORA networks, respectively.