You can configure bandwidth control for Wi-Fi devices with firmware version higher than 2.3.0.
How to configure the bandwidth per client for SSID
To configure the bandwidth control, follow these steps:
STEP 1
Once selected your Network, access to the WiFi SSID tab and select the one you want to configure.

STEP 2
Go to Bandwidth tab and click on Enable Bandwidth Limit.
Choose upload/download limit per SSID.

STEP 3
Click on APPLY to upload your new configuration.
Related Article:
Bandwidth control per client