One of the technologies that can lay the foundation for the next generation (fourth generation [4G]) of mobile broadband networks is popularly known as "WiMAX." WiMAX, Worldwide Interoperability for Microwave Access, is designed to deliver wireless broadband bitrates, with Quality of Service (QoS) guarantees for different traffic classes, robust security, and mobility. This article provides an overview of mobile WiMAX, which is based on the wireless local and Metropolitan-Area Network (MAN) standards IEEE 802.16-2004 [1] and 802.16e-2005 [2]. We introduce WiMAX and focus on its mobile system profile and briefly review the role of the WiMAX Forum. We summarize the critical points of the WiMAX network reference model and present the salient characteristics of the PHY and MAC layers as specified in [1] and [2]. Then we address how mobile nodes enter a WiMAX network and explain the fundamentals of mobility support in WiMAX. Finally, we briefly compare WiMAX with High-Speed Packet Access (HSPA), another contender for 4G.
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