The rising IEEE 802.16 normal, generally referred to as WiMAX, guarantees to ship final mile wi-fi broadband web entry able to carrying knowledge intensive purposes, resembling VoIP and streaming video, to Metropolitan Area Networks, in addition to sub-urban and rural communities. WiMAX is taken into account a disruptive expertise, designed as a substitute for fastened line DSL and coaxial applied sciences, and with its 802.16e revision, the cellular phone networks as properly.
Worldwide Interoperability for Microwave AXcess will function over licensed and non licensed frequencies utilizing non line of sight (NLOS) and line of sight applied sciences, extending broadband protection to cities and cities wirelessly through a metro space community. Additionaly, due to it’s miles reaching capabilities and ease of implementation, wimax is the one expertise likey to bridge the Digital Divide, connecting underdeveloped areas and sparsely populated rural areas far more cheaply than deploying a wireline infrastructure.
WiMAX and WiFi Compared
The widespread adoption of the wi-fi LAN in the enterprise group, in addition to the emergence of WiFi hotspots in public areas, airports, resorts and cafes, has been of great significance in offering mobility to enterprise individuals and shoppers alike. Thanks to the open requirements guided by the 802.11 committee and the WiFi Alliance, WiFi expertise is turning into ingrained in our society. WiMAX plans to take WiFi a step additional.
While the two applied sciences might sound the identical, they’re from their conception designed for completely totally different purposes. WiFi is a brief vary normal that was designed primarily as an extension of the native space community (LAN) to offer mobility for the finish consumer. It operates over unlicensed frequencies and has a spread of about 100 meters, relying on obstructions. Typically one entry level can be linked to a set line community, both a wired LAN or a DSL/cable broadband connection, and the vary may be prolonged by including extra entry factors at acceptable distances.
WiMAX, on the different hand, is designed to perform as a provider community, or a wi-fi Internet service supplier (WISP), blanketing entire cities and areas with broadband Internet entry similar to DSL. Coverage in optimum circumstances may attain 50 kilometers, however in actuality are extra like 5 km for customers with NLOS buyer premise gear (CPE), or as much as 15 km with a CPE linked to an exterior line of sight antenna.
As the older extra established expertise, the 802.11 WiFi has been utilized in a mesh topology to cowl bigger areas resembling school campuses and municipalities, for instance to attach the terminals in police autos to their database. The rising 802.16 WiMAX can be higher fitted to bigger deployments, and will in truth praise the non-public WiFi networks by providing a less expensive and safer Internet entry for knowledge and voice purposes.
The WiMAX Standards: Fixed, Nomadic, and Mobile
The 802.16 normal developed by the IEEE envisions a set wi-fi broadband community working in the spectrum vary of 10 GHz to 66 GHz. Originally, solely the licensed spectrum was addressed on this vary, and line-of-sight multipath expertise was handled by adopting OFDM as the normal. Subsequent revisions added the 2 GHz to 11 GHz band to the spectrum, and included help for non-line-of-sight applied sciences and Quality of Service (QoS) methods, a prerequisite for such time delicate purposes as voice and video.
The revision referred to as 802.16-2004(d) rolled up all the earlier revisions and then added some. Most of those authentic points handled the Physical and Media Access Control layers, and resulted in a requirements record of optionally available and obligatory parts by which distributors may design their merchandise.
The ensuing fastened WiMAX normal has an information charge of as much as 40 Mbps, help for half and full duplex transmission, improved QoS, and the incorporation of a number of polling methods, finally lowering packet collisions and overhead.
Base stations are to help a number of totally different topologies, resembling wireline backhauling, microwave level to level connections, and the capability for the WiMAX base station to backhaul itself by reserving part of the bandwidth for that objective.
By design, 802.16d would cater to the residential and small enterprise markets providing wi-fi broadband entry with speeds similar to DSL. Enterprise markets might be served at T1/E1 knowledge charges.
While this model of WiMax is known as fastened, it’s in all actuality nomadic. Users on a personal WiFi community indoors might be handed off seamlessly to the publicWiMAX community when shifting outdoor, their {hardware} figuring out the finest community obtainable. Devices on the WiMAX knowledge community would come with laptops, PDA’s, and good telephones outfitted with an on board WiMAX succesful chip or PC card, using the spectrum for voice, knowledge, video, and music transfers.
Nomadic WiMAX supplies for restricted mobility in that the vary of protection is dealt with by the identical base station.
WiMAX Goes Mobile
With the adoption of the 802.16e revision in late 2005, all the hype has been on Mobile WiMAX, a expertise designed to compete with the mobile networks.
With main help from producers like Intel, Motorola, Siemens, and Nokia amongst others, cellular WiMAX is constructed on open requirements and is presupposed to be 4 instances sooner than the mobile 3G applied sciences (EVDO, HSDPA). Significant value financial savings may be achieved for voice purposes by inserting calls over the Internet by VoIP.
802.16e supplies for quick and seamless handoffs between base stations, with a cell radius of about 3 miles, just like mobile networks. The normal was ratified in late 2005, and actual world purposes are starting to point out up in 2007, with extra strong growth anticipated all through 2008.
Because this expertise is such a risk to the legacy telecommunications business, it’s no shock that Sprint Nextel can be deploying WiMAX versus EVDO in its 4G community. Sprint has been shopping for up a lot of the WiMAX spectrum, and has just lately introduced a partnership with Nokia to deploy WiMAX to 4 Texas cities by mid 2008. This is just not their first WiMAX community, and telco’s round the globe have been doing the identical.
The 802.16 requirements are a piece in progress, and as such, are topic to adjustments and revisions. As the requirements committee works on the expertise, the WiMAX Forum hopes to do what the WiFi Alliance did for the 802.11 requirements, by selling interoperability between elements by testing, and providing WiMAX certification to distributors that conform to the 802.16 requirements.
It must be famous that a lot of the WiMAX implementations at the time of this writing are proprietary, and thus don’t essentially observe the suggestions of the IEEE or the WiMAX Forum. The broadband wi-fi ISP Clearwire Communications has over 200,000 subscribers in 375 cites, and calls its service a “WiMAX-class solution, utilizing next-generation, non-line-of-sight wireless technology.” Other early adopters of pre-WiMAX expertise are forging forward, offering wi-fi broadband entry to residential shoppers and the small enterprise market, with many corporations climbing aboard the evolving requirements bandwagon to guarantee interoperability and backwards compatibility of units and purposes.
