You can have the WLCs across the WAN from the Access Points (APs). Lightweight Access Point Protocol (LWAPP) works over a WAN. Use Remote Edge AP (REAP) mode. REAP allows the control of an AP by a remote controller that is connected through a WAN link. Traffic is bridged onto the LAN link locally, which avoids the need to unnecessarily send local traffic over the WAN link. This is one of the advantages of having WLCs in your wireless network.
Note: Not all lightweight APs support REAP. LAP1131AG and LAP1242AG do not support REAP at all, while 1030 AP supports REAP. But 1010 and 1020 AP do not support REAP. Before you plan to implement REAP, determine if the APs support it. Cisco IOS Software APs that have been converted to LWAPP do not support REAP. Both LAP1131AG andLAP1242AG support HREAP. It means that HREAP is supported for LWAPP converted IOS AP's.