WiMAX is similar to WLAN. If you are familar with WLAN, WiMAX will not be strange to you.
For MAC and PHY,
WiMAX deploys OFDM 802.16d and OFDMA 802.16e with changeable CP ,subcarriers and BW.
WLAN deploys OFDM with fix CP, subcarriers and BW.
For RF, they are almost the same except the operation frequency.