How WiMax Works 
WiMAX 8016 project started as far back as 1998, but the actual research and testing was completed in 2003 in an open agreement process. The aim of this project was to make broadband wireless access cover larger distances and affordable for a greater number of customers.
Figure 1: Types of Wireless Networks 
The wireless network technology has grown from a 33 foot radius personal Area network to a 30 mile radius Metropolitan Area Network, where WiMAX IEEE standard 8016 is taking place (Figure 1). The first version of the standard, WiMAX 8016, was published in April 2002 It offers the highest performance broadband technology except for broadcast and, on the wired side, and is on a level with satellite transmission. It delivers far higher rates and, with sufficiently widespread deployment, could significantly cut into the usage of cellular networks in many areas. WiMAX 8016-2004(d) is the version that has really kick-started WiMAX into being adopted as the dominant wireless broadband technology. This is also for fixed wireless but extends the range from 31 to 50 miles and operates in the low frequency and so can be adopted by unlicensed operators. It uses point-to-multipoint or mesh topologies. An important aspect of WiMAX is that it defines a media access control (MAC) layer that supports multiple physical layer (PHY) specifications. This is the key to allow equipment makers to differentiate their offerings.
WiMAX system consists of a WiMAX tower and associated receivers. A single WiMAX tower can provide service up to a great distance of 3,000 square miles. It is connected directly to the Internet using a high-bandwidth, fibre or T3 line connection. It can also connect to another WiMAX tower using a line-of-sight method. This connection between main towers is often referred to as backhaul. A WiMAX receiver could be built into laptops, phones or home similar to how Wi-Fi access is implemented today.
Figure 2: WiMAX Setup Mechanism 
Main WiMAX station is connected to the Internet backbone using fibre connections (Figure 2). All other WiMAX towers were connected using Line-of-Sight. At higher frequencies, there is less interference and more bandwidth. This helps the WiMAX towers to become stable during high-speed traffic. The WiMAX tower and client send traffic at a rate of 70-250Mbps, which is an extremely high-speed data rate for a wireless connection. In this scenario there might be non-line-of-sight connection that affects the system performance. To solve this issue, WiMAX uses OFDM technique, which selects higher frequency of the range 2 – 11 GHz and transmits signal at a higher power. This results in stabilizing the connection and its throughput comparable to the clients closer to WiMAX tower.
Applications such as voice and video, an extension 8016 has been developed, named the 8016a standard. It specifies a protocol that provides low latency applications and makes devices capable of broadband connectivity even when without a direct line of sight between subscriber terminals and the base station; and also has drastically increased the number users. Needless to say, this new standard will make the introduction of WiMAX into the marketplace more broad since it will enable the service providers not only to offer wireless broadband to its subscribers but also a strong dependable and affordable service.
Intel has called 8016 “the most important thing since the Internet itself”, and even allowing for a dose of self-serving, it is not talking entirely in hyperbole. There are areas of the world, especially in emerging markets and rural areas where deploying wired broadband infrastructure is not cost effective. WiMAX is extremely cost effective technology which can be quickly deployed in the regions which otherwise would not have broadband access. So WiMAX helps spread broadband to more users more quickly than existing technologies. WiMAX will be the most significant emerging technology to date in making wireless access ubiquitous and, as freer spectrum is opened up, in creating a major shake-up of the traditional shape of the wireless and mobile communications sector.
Last Revised: April 06, 2007 | Written by: Ajan Kanagalingam