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Written by: Randy Lee
Written on: November 1st, 2009
Tags: communication, computer science, lifestyle
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About the Author
Randy Lee was a senior at USC majoring in electrical engineering in 2009. He is interested in digital signals processing and audio engineering.
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Volume XI Issue II > WiMAX: The Next Generation of Wireless Technology
Today, it may seem like Internet access is ubiquitous, but a new wireless broadband system called WiMAX (Worldwide Interoperability for Microwave Access) promises to revolutionize the utility and accessibility of the Internet. WiMAX technology has a longer range, higher spectral efficiency, and ability to connect multiple users at the same time. It also has a built-in adaptive algorithm that can shift between higher performance and longer effective range. The range of services it can offer include voice, video, and data, as well as mobility. Because it requires a system of towers and receivers instead of a physical fiber-optic cable network, using WiMAX to provide Internet access to remote or inaccessible locations can be a cost effective alternative. With further development and adoption, WiMAX will offer consumers a complete wireless Internet package.

What is WiMAX?

Imagine having the ability to connect to the Internet while sitting on a train or car travelling at more than 65 miles per hour. On your next road trip, you can check your email, watch your favorite TV shows online, search for good restaurants – the possibilities are endless. With WiMAX technology, this is possible. WiMAX, also known as Worldwide Interoperability for Microwave Access, is a wireless telecommunications system that enables users to take advantage of high-speed wireless data transfer, like Wi-Fi. WiMAX has a wide range of coverage and is renowned for its ability to provide mobility to its video, voice, and data services. With wider implementation and further development, WiMAX may well become the next generation of wireless technology.

How It Works

The WiMAX network consists of two parts: a WiMAX tower and a WiMAX receiver. The WiMAX tower is directly connected to the Internet via physical wire connections and provides wireless coverage by sending out a signal at a particular frequency that is picked up by a WiMAX receiver embedded in a device, like a laptop or cellular phone. Although WiMAX towers can broadcast to a wide area, obstacles can weaken or stop the signal from traveling past it. To compensate for this and further expand their coverage, WiMAX towers use the process of backhauling. In WiMAX backhauling, a tower sends wireless signal to a second tower in its line of sight, enabling the second tower to operate as a base station without having to physically connect to the Internet.
The WiMAX network has a much longer range than other wireless Internet technologies, with a point-to-point range of 30 miles. Even at these distances, it can maintain a performance of 72 Mbps, which is multiple times faster than a regular residential Internet speed. WiMAX also has a non-line-of-sight (NLOS) range of up to 4 miles when there is an obstacle between the provider and the receiver, as shown in Fig. 1. It is able to maintain this kind of coverage because it uses advanced modulation algorithms that can overcome interfering objects [1]. WiMAX also operates on a licensed spectrum, whose use is protected by government authorities. This licensed spectrum eliminates the possibility of interference from other service providers [2].
Figure​ 1: In this image, the tower on the right is backhauled wirelessly to the original tower so that the homes still receive signal, even though they are blocked from the original tower's signal.
Another thing that sets WiMAX technology apart from other systems is that it uses a “dynamic adaptive modulation¨ that allows a particular base station to be able to exchange performance for range if needed [3]. If the base station needs to link to a distant subscriber, it would reduce its performance and consequently increase its effective range. With this dynamic property, WiMAX is a truly smart wireless technology, automatically adjusting its operations to maximize its efficiency.