One of the most often heard descriptions of WiMAX in the press is that it is “Wi-Fi on steroids”. In truth, it is considerably more than that. 
Not only does WiMAX offer exponentially greater range and throughput than Wi-Fi (technically speaking 802.11b, although new variants of 802.11 offer substantial improvements over the “b” variant of 802.11), it also offers carrier grade quality of service (QoS) and security. 
Wi-Fi has been notorious for its lack of security. The “b” variant of 802.11 offered no prioritization of traffic making it less than ideal for voice or video. 
The limited range and throughput of Wi-Fi means that a Wi-Fi service provider must deploy multiple access points in order to cover the same area and service the same number of customers as one WiMAX base station (note the differences in nomenclature). The IEEE 802.11 Working group has since approved upgrades for 802.11 security and QoS.