Adaptive coded modulation in physical layer of WIMAX

Abstract

The Institute of Electrical and Electronics Engineers (IEEE) 802.16 standard is a real revolution in wireless metropolitan area networks (Wireless MANs) that enables high speed access to data, video, and voice services. Worldwide Interoperability for Microwave Access (WiMAX) is the industry name given to the 802.16-2004 amendment by the vendor interoperability organization. IEEE 802.16 is mainly aimed at providing broadband wireless access (BWA) and thus it may be considered as an attractive alternative solution to wired broadband technologies like digital subscriber line (xDSL) and cable modem access. It’s main advantage is fast deployment which results in cost savings. Such installation can be beneficial in very crowded geographical areas like cities and in rural areas where there is no wired infrastructure. The IEEE 802.16 standard provides network access to buildings through external antennas connected to radio BSs. The frequency band supported by the standard covers 2 to 66 GHz. In theory, the IEEE 802.16 standard, known also as WiMAX, is capable of covering a range of 50 km with a bit rate of 75 Mb/s. However, in the real world, the rate obtained from WiMAX is about 12 Mb/s with a range of 20 km. The Intel WiMAX solution for fixed access operates in the licensed 2.5 GHz and 3.5 GHz bands and the licenseexempt 5.8 GHz band. This standard addresses the connections in wireless metropolitan area networks (WMANs). It focuses on the efficient use of bandwidth and defines the medium access control (MAC) layer protocols that support multiple physical (PHY) layer specifications. These can easily be customized for the frequency band of use.