Presented by
DEEPIKA SRINATH

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Introduction to WiMax and Broadband Access Technologies
What is WiMax?
WiMax (Worldwide Interoperability for Microwave Access) is a standards-based technology enabling the delivery of wireless broadband access as an alternative to cable and DSL.
The technology is specified by the Institute of Electrical and Electronics Engineers Inc., as the IEEE 802.16 standard.
WiMax Technology
WiMAX provides fixed, mobile wireless broadband connectivity without the need for direct line-of-sight (LOS) with a base station.
WiMAX provides Broadband Wireless Access (BWA) upto 30 miles(50 km) for fixed stations and 3-10 miles(5-15 km) for mobile stations.
Why is it Interesting?
Each station can provide 75 MBps download speed which can cover the entire city easily. Just imagine how it will be if DSL is going to cover everything with wires!!
They are low cost because they are wireless.
Scalability, as extra channels and base stations can be added incrementally as bandwidth demand grows.
Support for both voice and video as well as Internet data.
Wi-Fi: The Predecessor of WiMax
Wi-Fi (Wireless Fidelity) is a set of technologies that are based on the IEEE 802.11a,b, and g standards.
Wi-Fi is considered to be one of the first widely deployed fixed broadband wireless networks.
The Wi-Fi architecture consists of a base station that wireless hosts connect to in order to access network resources.
As long as the users remain within 300 feet(91.44m) of the fixed wireless access point, they can maintain broadband wireless connectivity.
Wi-Fi Standards
Strengths of Wi-Fi
Easy to install.
Cost of rolling out this wireless solution is low.
Users are able to be mobile for up to 300 feet(91.44m) from the access point.
Weaknesses of Wi-Fi
Limited level of mobility.
Designed technically for short-range operations(30-100m) and basically an indoors technology.
Security is a concern.
Relation of Wi-Fi and WiMax
WiMax eliminates the constraints of Wi-Fi.
Unlike Wi-Fi, WiMax is intended to work outdoors over long distances.
WiMax is a more complex technology and has to handle issues of importance such as NLOS.
Wi-Fi VS WiMAX
WiMax Standards
WiMAX Transmitter and Receiver
How WiMAX works
Service Types
WiMax can provide 2 forms of wireless service:
- Non-LOS, Wi-Fi sort of service, where a small antenna on a computer connects to the tower. Uses lower frequency range (2 to 11 GHz).

- LOS, where a fixed antenna points straight at the WiMax tower from a rooftop or pole. The LOS connection is stronger and more stable, so it is able to send a lot of data with fewer errors. Uses higher frequencies, with ranges reaching a possible 66 GHz.
NLOS and LOS
WiMAX Architecture
WiMax Spectrum
Broad Operating Range
There are 3 spectrum bands for global deployment:
Unlicensed 5 GHz: Includes bands between 5.25 and 5.85 GHz.
Licensed 3.5 GHz: Bands between 3.4 and 3.6 GHz
Licensed 2.5 GHz: The bands between 2.5 and 2.6 GHz have been allocated in the US, Mexico, Brazil and in some SEA countries.
Technical Similarities and Differences Between Licensed and License-Exempt Bands
Both solutions are based on IEEE 802.16-2004 standard, which uses OFDM in the physical (PHY) layer.
For creating bi-directional channels for uplink and downlink, licensed solutions use FDD while license exempt solutions use TDD.
Time Division Duplexing (TDD)
Frequency Division Duplexing (FDD)
Scope of 802 standards
PHY Layer Features of IEEE 802.16-2004
PHY Layer Features of IEEE 802.16-2004(Continued)
MAC Layer Features of IEEE 802.16-2004
MAC Layer Features of IEEE 802.16-2004 (Continued)
IEEE 802.16e-2005 Standard
Ratified in December, 2005
It is an extension of the IEEE 802.16-2004 standard
It covers MAC and PHY layers for Combined Fixed and Mobile Operation in Licensed Bands(2.5-2.6GHZ).
It will enable a mobile user to keep their connection while moving at vehicular speed (75-93 miles/h).
WiMax Mobility Issues
Device availability is a major issue
- Market introduction may be delayed
- High initial costs will limit adoption growth
- Many mobile operators have invested heavily in 3G systems.
Current demand for WiMax is mostly for fixed services.
WiMax Applications
WiMax supports the applications:
Multi-player Interactive Gaming.
Streaming Media.
Web Browsing and Instant Messaging.
Media Content Downloads.
WiMax Advantages
Being wireless there is no cluttering around.
Each station can provide 75 MBps download speed which can cover the entire city easily.
It removes the problem of maintaining wires and their connection which has shortcomings when it gets damaged somewhere.
WiMax Disadvantages
Bad weather conditions such as rain could interrupt the signal.
 WiMAX is a very power-consuming technology.
High installation and operational cost.