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WiMAX Technology
Frequently Asked Questions
What is WiMAX?
WiMAX (Worldwide Interoperability for Microwave Access) uses state‐of‐the‐art technology to transmit
radio signals from a sectorized base tower to a modem that is about the size of a book. The modem
easily connects to a subscriber’s computer, and once the subscriber plugs in the modem, the connection
is always on and always secure. Increasingly, laptops and other mobile devices are being embedded with
WiMAX chips and ports to receive WiMAX signals without the need for an external modem.
WiMAX operators currently use licensed spectrum (2.3 and 2.5 GHz) to deliver last‐mile fixed or mobile
broadband access to subscribers and businesses where traditional wireline services are not available.
The licensed spectrum ensures greater, more secure coverage without signal interference.
WiMAX also uses—
• IP network infrastructure to accommodate both data and voice without signal loss;
• Orthogonal Frequency‐Division Multiplexing (OFDM) technology for spectral efficiency, indoor
penetration, and more capacity; and
• Open IEEE standard 802.16 for economies of scale—equipment from all WiMAX Forum® certified
vendors is compatible and interoperable.
What are the benefits of WiMAX?
The benefits of wide‐area broadband coverage via WiMAX include:
• Fast speeds (2‐4 Mbps per user down and 1 Mbps up)
• Carrier‐grade quality of service (licensed spectrum)
• Mobile, portable or fixed end user equipment
• Affordable to the subscriber
• Ease of installation (on average more than 50 percent of subscribers can self‐install an indoor
modem in fewer than 10 minutes)
• Broad coverage areas (90+ square miles per base station based on a number of factors)
• Capital‐efficient (<10 percent the cost of cable/telco networks per household)
These benefits have launched WiMAX into the global market where the technology is expected to
continue its impressive growth trajectory. Global WiMAX tracks 455 commercial deployments in 135
countries and WiMAX service providers are on a path to reach 800 million people by the end of 2010
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How does WiMAX compare with other Internet access methods?
No other technology offers a full range of differentiated voice and data in a variety of wireless
fashions—fixed, portable and mobile.
WiMAX and Wi‐Fi
Although WiMAX and Wi‐Fi both offer wireless connections to the Internet, WiMAX uses licensed
spectrum (2.3 and 2.5 GHz), and Wi‐Fi uses unlicensed spectrum (900 MHz, 2.4 and 5.8 GHz). As a result,
WiMAX covers a broader service area than Wi‐Fi’s “hot spots” and has virtually no signal interference.
The licensed spectrum also makes WiMAX connections more secure and allows more flexibility than Wi‐
Fi. Some companies have successfully integrated Wi‐Fi into WiMAX networks, but the reverse cannot be
accomplished.
Numerous device manufacturers are incorporating WiMAX modems in addition to WiFi modems into
portable devices and mini laptops. The application will automatically select the best connection based
on the availability of service at a certain location.
WiMAX and WildBlue Satellite Internet
NRTC believes that extending broadband access to unserved and underserved areas is achievable by
offering a combination of wireless broadband service based on WiMAX technology and satellite
broadband. WiMAX provides a cost effective means to extend broadband to places where wireline
access may not be economical or where mobility is desired. Satellite Internet access will still be needed
for reaching such low population areas as farms or ranches, where neither wireline nor WiMAX
technologies prove economical.
WiMAX and LTE
Both WiMAX and LTE are 4G technologies designed to move data rather than voice and both are IP
networks based on OFDM. WiMAX, however, is based on the open IEEE standard (802.16), and that
means the equipment is standardized, less expensive and interoperable among equipment vendors.
WiMAX is already in deployment, whereas LTE will take time to roll out, and deployment forecasts say it
could reach limited adoption by 2012 in urban areas, even longer in rural areas.
Although LTE claims faster speeds than WiMAX, the technologies are similar in performance. Many
industry experts believe that manufacturers will make equipment that is compatible with both LTE and
WiMAX.
WiMAX and Fiber
Fiber and wireless co‐exist in the last mile. Although wireless deployment may grow significantly over
fiber due to ease of deployment and lower cost, especially in rural America, fiber is used where larger
bandwidth or greater distances are required.
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What are the average coverage distances and speeds?
Coverage areas from the towers are 5–7 miles outdoors (line of site) and 1–2 miles indoors (non‐line of
site), making an entire town a “hot spot.”
Speeds are from 2 to 4 Megabits per second (Mbps) down and 1 Mbps up on computers with the
WiMAX modem and any other devices with embedded WiMAX chips and ports. Higher speeds are
available for Enterprise subscribers. Technology advancements are expected to increase future speeds
to up to 12 Mpbs.
Can WiMAX work in any terrain?
Although some terrain can present special challenges, most conditions can be factored into initial
network planning and accommodated, because WiMAX uses:
• Licensed spectrum, not public‐use frequencies
• Higher power transmission – typically 40 Watts
• OFDM modulation and antenna diversity, which actually thrives on ‘multipath’
By adjusting the modulation and transmission channel characteristics, non‐line of sight is achieved in
most cases. Terrain factors are built into both the business case as well as the radio network plan for all
deployments.
How tall do the towers need to be? How far apart should the towers be?
The height of the tower, number of towers and propagation pattern are unique to each town or market,
influenced by building types and density and terrain. Specific network planning can be completed to
identify best existing tower and other vertical real estate options for your market. Generally, the towers
that DigitalBridge Communications (NRTC’s WiMAX partner) has deployed range from 50 to 200 feet tall.
The distance between the towers varies according to such factors as terrain, foliage and how much
coverage you want to provide. On average, they are 6 to 7 miles apart.
What equipment vendor does DigitalBridge Communications use?
Currently, DBC uses Alvarion for both core transmission network gear and for customer premises
equipment (CPE), but since WiMAX is a standards‐based technology, interoperability with other WiMAX
gear meeting that standard will be possible.
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What is the latency and are there weatherrelated outages?
WiMAX provides high quality of service with virtually no signal interference or weather‐related outages
and fewer than 60 milliseconds of latency.
Are WiMAX subscribers subject to a Fair Access Policy?
There is no limit to the amount of bandwidth subscribers can use, within the terms of the service
agreement for their particular package.
When is a professional installation necessary, and what is involved?
On average, more than half of subscribers are expected to be able to perform a self‐installation by
connecting an indoor modem to their computer. The remaining subscribers (generally located beyond
2 to 3 miles of a tower) will require professional installation. The mix of self‐installation to professional
installation will be determined by the Radio Access Network plan, your coverage goals and how your
network is built.
NRTC members will have pre‐qualified subscriber addresses based on the certified and approved radio
network plan, so they will know to a great degree who can be served with a self‐install and who needs a
professional install.
The professional installation requires placing an antenna under the eve of the roof on the subscriber’s
house. The work required is significantly less complicated than a DIRECTV or WildBlue antenna
installation.
What are some typical technical support issues with WiMAX?
As with many broadband services, DigitalBridge Communications has experienced most support
requests within the first 30 days of service and most were related to customer education as opposed to
WiMAX network issues. Issues include setting up e‐mail and ancillary device configurations, like wireless
routers and Xbox.
How can I find information about available 2.3 or 2.5 GHz spectrum in my
area?
NRTC is compiling a list of 2.3 and 2.5 GHz spectrum holders in the United States. To date, these are the
only two spectrums in the WiMAX‐certified license ban. If you are interested in becoming a WiMAX
provider through DigitalBridge, NRTC and DBC will help you secure spectrum. You do not need to go to
spectrum brokers to obtain spectrum.
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What is the estimated time to have a WiMAX system operational?
Once NRTC and DigitalBridge have pre‐qualified you as a WiMAX candidate, and you execute a
distribution agreement, your system can be operational in as little as four to six months.
I’m interested in learning whether WiMAX is a feasible lastmile solution
for my community. What do I do next?
To learn more about how WiMAX from DigitalBridge can expand your existing broadband infrastructure,
contact your NRTC Regional Business Manager (RBM). Call 866‐672‐6782 or visit www.nrtc.coop.
The Regional Business Manager will answer your questions and, depending on your interest, have you
complete a WiMAX Technology Interest Assessment to determine the feasibility of deploying WiMAX in
your area. Following that, we can complete a pre‐qualification analysis that includes a Radio Access
Network (RAN) map to estimate the specific build‐out requirements for the areas you want to serve.
The cost for the pre‐qualification analysis is $7,500.
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