Using a SCA means that all APs will be using the same channel in a...

All APs share a virtual Multicast Address. A controller will tell the closest AP to the client to communicate with it, since it has a greater RSSI from the client.

All APs share a virtual BSSID. A controller will tell the closest AP to the client to communicate with it, since it has a greater RSSI from the client.

All APs share a virtual IP address. A controller will tell the closest AP to the client to communicate with it, since it has a greater RSSI from the client.

The client selects the AP based on a known set of MAC to BSSID mappings stored in the clients authorized SSID listing.