4
IEEE WiMAX
4.1 Introduction
Chapter 4 describes the latest radio access technology that has been incorporated into IMT-2000 that is, WiMAX (Worldwide Interoperability for Microwave Access). In October 2007, the ITU-R (Radio-communication Sector of the International Telecommunication Union) approved WiMAX as a global 3G communications standard and incorporated it to complement the existing family of IMT-2000 radio interfaces. The IEEE 802.16 WiMAX standard enables the delivery of last mile wireless broadband access as an alternative to wireline broadband technologies like Cable and DSL and to wireless technologies like EV-DO, HSPA and LTE.
The two key players in the development of WiMAX are: IEEE and WiMAX Forum as shown in Figure 4.1. The IEEE 802.16 standardization work started in the late 1990s and completed the first specifications – IEEE 80.16-2001 in April 2002. The IEEE 802.16-2001 standard was designed for fixed wireless systems that operate in 10-60 GHz frequencies and requires LOS (line of sight) like LMDS (Local Multipoint Distribution Service).1 The next steps were to remove LOS requirement, add portability and mobilization to the broadband systems. To achieve these tasks, the IEEE 802 committee first standardized IEEE 802.16-2004 (to remove LOS weakness) and then completed IEEE 802.16e (to add mobility) standard. Although 802.16e air interface specifications supports systems below 11 GHz, the systems are mainly available in 2.3, 2.5, and 3.5 GHz. Since IEEE only ...
