Most Ruckus APs today are dual-band, supporting clients simultaneously on 2.4G and 5G, independent of one another.
Client load-balancing will attempt to keep even capacity between the AP radios, by monitoring client capabilities and "steering" clients to 5G.
Air Time Fairness, insures that legacy radio clients ie, 802.11b/g only, do not inhibit the throughput of 802.11n/ac capable clients,
by implementing a weighted TDM methodology.