WiMAX

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WiMAX

• Worldwide Interoperability for Microwave Access

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Overview of WiMax

• Short for Worldwide Interoperability for
  Microwave Access, and it also goes by the IEEE
  name 802.16.
• Wireless solution to metropolitan area network
  (MAN). A MAN allows areas the size of cities to
  be connected.
• New technology that proposes to solve problems of
  broadband access and WiFi access.
• New WiMAX technology would provide
• The high speed of broadband service
• Wireless rather than wired access
• Road coverage like the cell phone network instead
  of tiny little hotspots of WiFi

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How WiMax Works

• A WiMAX system consists of two parts
• A WiMAX tower, similar in concept to 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).
• 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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WiMAX Transmitting Tower
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WiMAX Equipment
Aperto Networks antenna and modem
Alvarion Base Station and Customer Premises
equipment
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A WiMAX tower station can connect directly to the
Internet using a high-bandwidth, wired
connection. 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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What Can WiMAX Do?

• WiMAX operates on the same general principles as
  WiFi -- it sends data from one computer to
  another via radio signals.
• A computer (either a desktop or a laptop)
  equipped with WiMAX would receive data from the
  WiMAX transmitting station, using encrypted data
  keys to prevent unauthorized users from stealing
  access.
• WiMAX should be able to handle up to 70 megabits
  per second. It will provide at least the
  equivalent of cable-modem transfer rates to each
  user.
• 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 of 30 miles (50 km) with
  wireless access.

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WiMAX can provide two forms of wireless service

• Non-line-of-sight, WiFi sort of service, where a
  small antenna on your computer connects to the
  tower. In this mode, WiMAX uses a lower frequency
  range -- 2 GHz to 11 GHz (similar to WiFi).
  Lower-wavelength transmissions are not as easily
  disrupted by physical obstructions -- they are
  better able to diffract, or bend, around
  obstacles.
• 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, with ranges
  reaching a possible 66 GHz. At higher
  frequencies, there is less interference and more
  bandwidth.

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Two main applications for WiMAX

• Fixed Wireless
• Phase One Outdoor, professionally installed
  antennas providing high speed service to
  businesses. Also, will serve in a backhaul
  role, linking WiFi hot spots to the greater
  Internet.
• Phase Two Introduction of indoor,
  self-installable Customer Premises Equipment
  (CPE). Consumers will be able to bring home a
  box resembling a cable modem, plop it down
  anywhere in the house and receive high speed
  service.
• Mobile Wireless
• Phase Three Manufacturers to integrate WiMAX
  into PC Cards, laptops, and other portable
  devices to enjoy high speed connectivity at home,
  around town, and even while speeding down the
  highway.

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• Main problems with cable and DSL technologies
• DSL can only reach about 18,000 feet (3 miles)
  from the central office switchmany urban,
  suburban and rural locations may not be served.
• Many older cable networks havent been equipped
  to provide a return channel and converting these
  networks to support high-speed broadband can be
  expensive.
• Cost of deploying cable is a significant
  deterrent to the extension of wired broadband
  service in areas with low subscriber density.
• Main problems with WiFi (802.11) access
• Hot spots are very small, so coverage is sparse.
• Current generation of proprietary wireless
  systems are relatively expensive for mass
  deployments because, without a standard, few
  economies of scale are possible.

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WiMAX Solves these Problems and More

• Can provide service to underserved areas
• Can fill in the gaps in cable and DSL coverage
• Line of sight not required
• Provides high bandwidth
• Inherent flexibility and low cost helps to
  overcome the limitations of traditional wired and
  proprietary wireless technology
• Privacy and encryption features are included in
  802.16 standard
• Standards based technology

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Benefits of Standards

• Enables economies of scale that can bring down
  the cost of equipment
• Without industry-wide standards, equipment
  manufacturers must provide all the hardware and
  software building blocks and platforms themselves
• Ensures interoperability
• Ensures compatibility and interoperability of
  broadband wireless access equipment
• Establishes a subset of baseline features and
  protocol that all compliant equipment must
  satisfy- allows equipment from multiple vendors
  to interoperate
• Allows service providers to purchase equipment
  from more than one supplier

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Drawbacks to WiMAX

• Certain conditions terrain, weather and large
  buildingscan act to reduce the maximum range.
• Limited underserved customer base--Approx 85 of
  U.S. households can now buy broadband services
  and about 70 have a choice between DSL and
  cable.
• Most commercial WiMAX services likely to be small
  in scalemarkets limited to hard-to-reach rural
  areas or city neighborhoods that arent already
  hooked up for broadband.
• Cost to build a nationwide network could reach 3
  billion.
• Scarcity of suitable airwaveslicensed airwave
  frequencies are allocated by the FCClimited
  availability. Unlicensed airwaves are free but
  all can use themdifficult to control service
  quality as other users of the same band could
  cause interference.