Evaluation of HARQ for improved link efficiency within dense IEEE 802.11 networks

The progressive adoption of Wi-Fi networks in commercial verticals (dense deployments in buildings, robotics control, gaming) is leading to densification, which demands improvements in reliability and performance guarantees (improved throughput with low latency). Based on these requirements, the IEEE 802.11 working group aims to develop a new amendment called IEEE 802.11be. Hybrid Automatic Repeat Request (HARQ), an enhanced link adaptation and retransmission protocol, is one of the leading candidate features introduced in the IEEE 802.11be. HARQ has the potential to be used in any Wi-Fi configuration (number of antennas, use of MIMO, or channel bandwidth, etc.). In this work, HARQ Chase Combining is modeled in the ns-3 simulator. This new simulation code has been designed and developed considering a contribution to developing the future IEEE 802.11be simulator model within ns-3. Through extensive simulations, we demonstrate the potential advantages of introducing HARQ in dense deployments, particularly for stations amid a large number of contending stations that make transmission attempts simultaneously. Based on the insightful results, we indicate HARQ as a remedy to alleviate the side effects of Dynamic Sensitivity Control (DSC) technique proposed to improve spatial reuse (i.e., combined throughput increase of approx. 18 % and a decrease of 4 % in error rate for the spatial reuse method). To the best of our knowledge, this is the first and novel comprehensive evaluation of HARQ under extremely heavily loaded Wi-Fi conditions.