WiMAX

From Isopedia

1 Technical Information
2 Historical Information
3 References
4 Team Members

Technical Information

WiMAX is a term used to describe standard, interoperable implementations of IEEE 802.16 wireless networks. WiMax works like Wi-Fi, however WiFi implements the IEEE 802.11 Wireless LAN standard. However, WiMAX works differently than Wi-Fi in many ways. WiMax uses the 802.16 media access controller as a scheduling algorithm, where the subscriber station competes only once to enter into the network. At that point, it is given a time slot by the base station. If this time slot remains assigned to the subscriber station, no other subscribers can access it. Unlike WiFi’s 802.11, the scheduling algorithm can withstand overscription and overload. Because the scheduling algorithm is balancing the time-slot assignments between the needs of the various subscriber stations, the base station can control QoS parameters. The original standard placed WiMAX in the 10 to 66 GHz range. In the past few years, WiMax has been updated to allow for larger GHz ranges. Recently in 2005, it was updated to 802.16e. Originally WiMax used a non-scalable version of orthogonal frequency-division multiplexing. As part of the 802.16e revision, the frequency division is now scaleable.The benefits of this revision include bandwidth efficiency, power consumption, coverage, frequency re-use and self installation. The revision also provides the potential full mobility. The 802.16e gives improved range and in-building penetration. It provides stronger encryption and connectivity through endpoints without the requirement of direct line of sight.

Historical Information

The internet was originally intended to share data between a few universities and government agencies. From this, the internet grew to what it is today, which allows connectivity from anywhere on earth and beyond. The internet is capable of reaching ships out at sea and even into space as well. There were three main networks that led to the internet, and they were ARPANET, X.25, and UUCP. The ARPANET was developed and used by the U.S. Department of Defense, it was the world’s first operational network and a beginning look at the future internet to come. X.25 was a standard protocol suite for wide area networks using the phone line as the networking hardware, and the third network was created in 1979 by two students from Duke University trying to transfer new and messages on a serial line to nearby UNC at Chapel Hill. These three networks were brought together to create the basis for the internet that we know today. Over the past few years new breakthroughs have been made in connecting to the internet, such as cable modems, DSL modems and Ethernet. Through these different connections came the ability to form a wireless internet connection. Which brought about the introduction of Wi-Fi. Wi-Fi began in 1991 by the NCR Corporation/AT&T in the Netherlands. It was originally intended for cashier systems and the first wireless products were brought on the market under the name WaveLAN. Vic Hayes, who was the leading inventor of Wi-Fi, was involved in designing standards such as IEEE 802.11b, 802.11a and 802.11g. The cousin to Wi-Fi, WiMAX (Worldwide Interoperability for Microwave Access) was created in April of 2001, and originally it was intended to be an alternative to DSL and cable modem broadband and also to be used in areas where cable or DSL connection is not available. The WiMAX Forum is a group of companies working together to create WiMAX. The WiMAX standard, IEEE 802.16 was then developed in January 2003. Later in June of 2004, 256 OFDM was selected by WiMAX, which allowed for more data to be transferred and at higher speeds. In the end of 2005 the fixed WiMAX standard that is identified by 802.16 and uses the 256 OFDM mode, began to convert into the mobile standard that is identified by 802.16e and uses the mode OFDMA. WiMAX has been designed to be compatible with European standards, which Wi-Fi was not able to do.