Abstract—Even with the advanced capabilities of IEEE 802.11ax (Wi-Fi 6), dense Wireless Local Area Networks (WLANs) often struggle to meet the strict latency demands of modern applications. High-efficiency features like OFDMA and Target Wake Time (TWT) improve spectral efficiency, yet they cannot prevent network saturation when traffic demand simply outstrips the available airtime. To address this, we introduce an Airtime-Based Soft Call Admission Control (AS-CAC) framework designed specifically for saturated, multi-access point environments. Instead of relying on hard connection limits, our approach regulates access based on the actual airtime required by each flow. A key strategy is the “Soft-CAC” mechanism, which moves beyond static thresholds. It strictly prioritizes real-time streams like VoIP and Video but remains flexible enough to admit best-effort bursty traffic whenever spare capacity exists, maximizing channel utilization without breaking QoS guarantees. We further enhance this with AS-CAC+, an adaptive variant that dynamically adjusts thresholds based on network health. We validated this framework using extensive ns-3 simulations, backed by a theoretical multi-rate Erlang loss model. Results from dense deployment scenarios including those with Co-Channel and Adjacent Channel Interference show that AS-CAC stabilizes throughput and keeps end-to-end VoIP latency under 2 ms, a dramatic improvement over the 45+ ms delays seen in uncontrolled networks. AS-CAC+ achieves 19.2% throughput improvement and 97.4% channel utilization while maintaining strict QoS. These findings offer a practical, scalable strategy for next-generation enterprise WLANs.