Is it required that the AP gets an IP address via DHCP? It looks like it is required initially for association to the WLC. However, after the association, does it need to maintain the IP address? And if so, why? It seems that the WLC can communicate with the AP by it's MAC and wouldn't need an IP after the association to the WLC.
The ap needs an ip address to join the WLC when layer 3 is enabled on the wlc. What you are talking about is when layer 2 is enabled which is for the old airespace ap's. This will not work for youwith the 1131 LAP's. You can console into the LAP and configure an ip address or else, you will have to use DHCP.