The WiMax family of standards (802.16) concentrate on two types of usage models a fixed WiMax usage model and a mobile WiMax usage model. The basic element that differentiates these systems is the ground speed at which the systems are designed to manage. Based on mobility, wireless access systems are designed to operate on the move without any disruption of service; wireless access can be divided into three classes; stationary, pedestrian and vehicular.
Broadband service and consumer usage of fixed WiMax access is expected to reflect that of fixed wire-line service, with many of the standards-based requirements being confined to the air interface. Because communications takes place via wireless links from WiMax Customer Premise Equipment (WiMax CPE) to a remote Non Line-of-sight (NLOS) WiMax base station, requirements for link security are greater than those needed for a wireless service. The security mechanisms within the IEEE 802.16 standards are sufficient for fixed WiMax access service.
The 802.16a extension, refined in January 2003, uses a lower frequency of 2 to 11 GHz, enabling NLOS connections. The latest 802.16e task group is capitalizing on the new capabilities this provides by working on developing a specification to enable mobile WiMax clients. These clients will be able to hand off between WiMax base stations, enabling users to roam between service areas.