How to maximize the wireless throughput?

Issue: My wireless throughput is lower than expected. How can I maximise the throughput?

Root cause: On Desktop clients connected to an OpenWrt AP: The network manager might scan for other stations every (nr of seconds) in background. This results in a measurable periodic drop in wireless throughput (ex: measured with iperf). regular drops with nm and deactivated nm. There is an open bug report on upstream gnome bugzilla #742085