  Real-time applications (RTAs) require low delays and impose a significant
challenge to Wi-Fi. In Wi-Fi, high delays are often caused by waiting for the
channel to become idle. This problem can be solved with Parameterized Spatial
Reuse (PSR), which allows a station (STA) to transmit its frame with reduced
power simultaneously with a triggered uplink transmission in an overlapping
network. The PSR opportunity depends on the pathloss between involved STAs, so
the same transmission may allow PSR for one STA but not for another one. Thus,
to satisfy tight delay constraints in dense overlapping networks, access points
(APs) in the same area shall often allow PSR for every STA with RTA traffic.
This letter proposes a fast scheduler enabling frequent PSR transmissions for
RTA traffic. The scheduler uses Multi-AP coordination, the feature of upcoming
Wi-Fi 8. With simulations, we show that it almost halves the delay for RTA
traffic and does not deteriorate the quality of service for other traffic
compared with an airtime fairness scheduler.
