Wimax General By Debashree

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WiMAX, meaning Worldwide Interoperability for Microwave Access, is a telecommunication technology that provides wireless transmission of data .

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WiMAX is wireless broadband technology, and a great alternative to fixed broadband connections such as cable or DSL.

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The technology is based on the IEEE 802.16 standard (also called Broadband Wireless Access).

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WiMAX is led by the WiMAX Forum, a global organisation of manufacturers and operators, who share knowledge and developments to ensure compliance and international compatibility in WiMAX technology as per the IEEE 802.16 standard.

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The name "WiMAX" was created by the Forum, which was formed in June 2001.

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WiMAX Wireless Network

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In practical terms, WiMAX would operate similar to Wi-Fi but at higher speeds, over greater distances and for a greater number of users.

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WiMAX could potentially erase the suburban and rural blackout areas that currently have no broadband Internet access, as the phone and cable companies have not yet run the necessary wires to those remote locations.

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WiMax is the industry term for a long-range wireless networking standard.

WiMAX system consists of two parts: •

A WiMAX tower - similar in concept of a cell-phone tower - A single WiMAX tower can provide coverage to a very large area -- as big as 3,000 square miles (~8,000 square km).

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A WiMAX tower station can connect directly to the Internet using a highbandwidth, wired connection .

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It can also connect to another WiMAX tower using a line-of-sight, microwave link. This connection to a second tower (often referred to as a backhaul), along with the ability of a single tower to cover up to 3,000 square miles, is what allows WiMAX to provide coverage to remote rural areas.

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A WiMAX receiver - The receiver and antenna could be a small box or PCMCIA card , or they could be built into a laptop the way WiFi access is today.

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What this points out is that WiMAX actually can provide two forms of wireless service:

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There is the non-line-of-sight - Wi-Fi sort of service, where a small antenna on the computer connects to the tower. In this mode, WiMAX uses a lower frequency range -- 2 GHz to 11 GHz (similar to Wi-Fi). Lower-wavelength transmissions are not as easily disrupted by physical obstructions -- they are better able to diffract, or bend, around obstacles.

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There is line-of-sight service, where a fixed dish antenna points straight at the WiMAX tower from a rooftop or pole. The line-of-sight connection is stronger and more stable, so it's able to send a lot of data with fewer errors. Line-of-sight transmissions use higher frequencies . At higher frequencies, there is less interference and lots more bandwidth.

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WiMAX Could also Boost Government Security

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In an emergency, communication is crucial ,for government officials as they try to determine the cause of the problem, find out who may be injured and coordinate rescue efforts or cleanup operations. A gas-line explosion or terrorist attack could sever the cables that connect leaders and officials with their vital information networks.

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WiMAX could be used to set up a back-up or even primary communications system that would be difficult to destroy with a single, pinpoint attack. A cluster of WiMAX transmitters would be set up in range of a key command center but as far from each other as possible. Each transmitter would be in a bunker hardened against bombs and other attacks. No single attack could destroy all of the transmitters, so the officials in the command center would remain in communication at all times.

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WiMAX Coverage and Speed

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WiMAX operates on the same general principles as Wi-Fi -- it sends data from one computer to another . A computer (either a desktop or a laptop) equipped with WiMAX would receive data from the WiMAX transmitting station, probably using encrypted data keys to prevent unauthorized users from stealing access.

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The fastest WiFi connection can transmit up to 54 megabits per second under optimal conditions. WiMAX should be able to handle up to 70 megabits per second. Even once that 70 megabits is split up between several dozen businesses or a few hundred home users, it will provide at least the equivalent of cable-modem transfer rates to each user.

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The biggest difference isn't speed; it's distance. WiMAX outdistances WiFi by miles. WiFi's range Is about 100 feet (30 m). WiMAX will blanket a radius of30 miles (50 km) with wireless access. The increased range is due to the frequencies used and the power of the transmitter.

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Features

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WiMax have lots of features to its name. Lots of limitations were found as the use of Wifi technology grew around the world, to overcome these limitations and to invent better and more efficient wireless technology was realized which turned out to be WiMax. WiMax have lots of features which helped in its increase usability around the world. however some of its significant features which are important enough to mention.

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Long Range

Connectivity from long range is much highlighted feature of WiMax. Theoretically it is believed that WiMax technology provides range up 30 miles (50 Km).

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Mobility

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Another significant feature of WiMax technology is the connectivity on move. This technology amaze the world hence increasing the use of WiMax in some parts of the world dramatically. Especially to the rural places where cables and other network equipments are not feasible to install. Using its long range feature it provides connectivity on such area where other means of high speed Internet are not available.

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Interfacing WiMax radio signals are broadcasted to its subscribers from base stations. Base stations are area where all necessary hardware is installed to provide WiMax within its range. Since one Base station covers limited range so connecting multiple base stations to each other increase that much range for connectivity. Connecting multiple base stations to each other is not big task and can be perform in few hours.

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Accessibility

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Accessing WiMax base station is not a difficult task, its long range capability provides connectivity at home from base stations within the range. To get high speed internet it’s only required to be subscriber to WiMax service providers. They will provide appropriate hardware to become the subscriber. Installing the hardware is very easy. Hardware mostly connects through USB ports or Ethernet and connection can be made by clicking just a button.

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There may be several other features which will surely come up as the growth of WiMax technology increases.

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Limitations:

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As in all wireless or wired networks, the given bandwidth is divided among the users, it is same in WiMax also, available bandwidth is divided among the users in certain radio sector, and performance of the network can drop in case of many users in a given sector. To improve the performance in this situation more radio cards are required to be installed in the base station for given sector.

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Because of this varying performance of WiMax networks, lots of architectures are incorporated into WiMax by independent development and within the 802.16j mobile multi-hop relay (MMR) task group.

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there is lots of confusion among both wimax and wifi technologies. There are many reasons for that, one could be both technologies starts with W letter, that makes some people think that they both are same technologies with different names. There is one more major reason why it makes confusing, they both belong from standard setter IEEE and there standards first 3 letter are same “802”, and both wifi and wimax technologies belong from Wireless connectivity family.

APPLICATIONS •

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These are most common applications of WiMAX which can be used for Broadband Wireless Access (BWA). 1. Residential or Home and Broadband Internet Access: DSL and cable internet technologies are widely used in residents . These technologies have strong hold on market by satisfying and meeting the needs of broadband internet users. Taking over from these users for WiMAX technology based internet may be not possible at given time, however internet provided by WiMAX bases station towers can be well utilized within the rural areas where DSL and Cable internet facilities are not available. Using WiMAX internet technology brings reliability to the customers as it being the wireless in nature there are no apparent mediums required to use it. WiMAX base station will simply connect to customer premises device and that will be all. Deploying WiMAX technology is very useful for developing countries where setup and reliability of Land line telecommunication infrastructure is poor.

2. Medium and small size business: • The WiMAX Wireless broadband Access (WBA) can be very well suited to provide the reliability and can meet the needs of small to medium scale business especially in low density area, whereas this may not work at its full potential in the area of high density. It has spectral limitation issues. There is a possibility that bandwidth may not be sufficient enough to provide access to large clients in high density area. This could bring the cost way up.

3. Backhaul networks for cellular base stations: • Backhaul networks for cellular base stations can be provided by bypassing the PSTN networks, Public Switched Telephone Network. This cost effective alternative can be achieved by cellular services by looking into Wireless backhaul. Strong WiMAX technology can be preferable choice for backhaul for enterprises such as hotspots and point to point backhaul access solutions. 4. WiFi Hotspots.

This can allow users to access internet remotely by roaming out side office and homes. There are several Hotspots and WiMax backhauls which are providing wireless solutions to wireless networks.

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