The increasing demands for high-speed mobile Internet access over the past few years have motivated the development of broadband wireless access technologies. Mobile WiMAX (based on IEEE 802.16e-2005 standard) provides a solution to meet the demands. This paper will present a high-level overview of the development of Mobile WiMAX and the key technologies involved in Mobile WiMAX. This paper will also address the future development issues for Mobile WiMAX.
IEEE802.16e-2005, Mobile WiMAX, OFDMA, MIMO, PHY, IEEE802.16m
In the past few years, the demands for high-speed mobile Internet access have been growing significantly. The increasing demands for mobile Internet access have stimulated operators and vendors in telecommunications sectors to explore and create new technologies to offer such kind of services at a low-cost and highly-efficient basis. Mobile WiMAX (Worldwide Interoperability for Microwave Access), referred to as the IEEE802.16e-2005 standard, is a fast growing broadband access technology that offers higher data rates than existing 3G technologies to enable low-cost multimedia services and Internet applications on mobile devices .
Two key technological breakthroughs in wireless communications are integrated into the Mobile WiMAX standards, namely Orthogonal Frequency Division Multiple Access (OFDMA) and Multiple-Input Multiple-Output (MIMO) antenna technology [1-2]. OFDMA is the chosen technology for the Physical (PHY) layer of Mobile WiMAX. MIMO technology improves cell coverage areas for mobile WiMAX systems. OFDMA and MIMO have enabled Mobile WiMAX to provide reliable solution to address increasing demands on mobile Internet access.
This paper presents a high-level overview of Mobile WiMAX (IEEE802.16e-2005) in terms of its standardization roadmap and the key technologies involved. Besides, this paper will give a brief discussion on the system performance and future development of Mobile WiMAX (IEEE802.16m) Finally, this paper will provide some concluding remarks on the prospects of Mobile WiMAX.
WiMAX Standardization Roadmap
Two bodies mainly contribute to the development of WiMAX technology – the IEEE802.16 working group and the WiMAX Forum . The IEEE 802.16 working group has been proposing several versions of air-interface standards known as WiMAX for Wireless Metropolitan Area Networks (WiMANs). The WiMAX Forum is an industry-led organization formed in 2001 to certify and promote broadband wireless products based upon the IEEE 802.16 standards. WiMAX system is certified by the WiMAX forum.
The first IEEE802.16 standard (IEEE802.16-2001) was approved in 2001. It operates in the 10–66 GHz band and only supports line-of-sight (LOS) point to multi-point transmissions. It uses a single carrier (SC) modulation scheme as its PHY layer. IEEE802.16a, approved in 2003, was an amendment to 802.16-2001 and operates in the 2–11 GHz band. It supports a non-line-of-sight (NLOS) capability and aims to provide "last mile" fixed broadband access. Therefore the PHY layer technology was extended to Orthogonal Frequency Division Multiplex (OFDM) and OFDMA. IEEE802.16-2004 was a further amendment to the previous 802.16 standards and is often referred to as “Fixed WiMAX”. An amendment to 802.16-2004, IEEE802.16e-2005 aims to address mobility in cellular networks. IEEE802.16e-2005 has a number of enhancements to 802.16-2004 in terms of better support for Quality of Service (QoS) and the use of Scalable OFDMA . IEEE802.16e-2005 is often referred to as “Mobile WiMAX”. IEEE802.16e systems support data rate up to 63Mbps and mobile users moving at speed up to 120km/h. However, in order to meet the requirements of IMT-Advanced (International Mobile Telecommunications – Advanced, an International Telecommunication Union (ITU) platform of 4G wireless systems), Mobile WiMAX system must support data rate up to...