The IEEE 802.16 is a set of standards that lays down the specifications for wireless broadband technology. It has been commercialized as Worldwide Interoperability for Microwave Access (WiMAX) that is responsible for delivery of last mile wireless broadband access. It lays down the standards for both physical layer as well as medium access control (MAC) layer for WiMAX.
Fixed WiMAX was released in 2003. They are for subscriber stations that are stationary in some fixed location. For example, broadband Internet for homes and offices. Fixed WiMAX uses OFDM.
Mobile WiMAX was released in 2005. They are for mobile stations that receive service while they are in motion within the range of WiMAX. For example, a WiMAX equipped vehicle. Mobile WiMAX uses scalable OFDM.