1. Worldwide Interoperability for Microwave Access
WiMAX(IEEE 802.16)
by
E. Kishore Kumar

2. Out line
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1.History
2.Specification
3.Architectur
4.Physical layer
5.MAC layer
6.Opetation Network
7.Application
8.Advntage &Disadvantage
9.Conclusion

3. Why we need broadband wireless
access?
• Fill the gap and high data rate wireless LAN
and mobile cellular networks.
• Provide high-speed mobile data and
telecommunications services

4. Wireless networks
•
Wireless PANs (Bluetooth – IEEE
802.15)
– very low range
– wireless connection to printers etc
•
Wireless LANs (WiFi – IEEE 802.11)
– infrastructure range
– home/office networking
•
Wireless MANs (WiMAX-802.16)
– Similar to cellular networks
– traditional base station
infrastructure systems

5. Standards
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IEEE 802.16 (2001)
– Air Interface for Fixed Broadband Wireless Access System MAC and PHY
Specifications for 10 – 66 GHZ (LoS)
– One PHY: Single Carrier
– Connection-oriented, QoS, Privacy
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IEEE 802.16a (January 2003)
– Amendment to 802.16, MAC Modifications and Additional PHY Specifications for 2 –
11 GHz (NLoS)
– Three PHYs: OFDM, OFDMA, Single Carrier
– Additional MAC functions: OFDM and OFDMA PHY support, Mesh topology support,
ARQ
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IEEE 802.16d (July 2004)
– Combines both IEEE 802.16 and 802.16a
– Some modifications to the MAC and PHY
•
IEEE 802.16e (2005)
– Amendment to 802.16-2004
– MAC Modifications for limited mobility

6. Introduction
Coverage range up to 50km and speeds up to 70Mbps(shared among users).

7. Specification
802.16
802.16a
802.16-2004
802.16e-2005
Date
Completed
December 2001
January 2003
June 2004
December 2005
Spectrum
10-66 GHz
< 11 GHz
< 11 GHz
< 6 GHz
Operation
LOS
Non-LOS
Non-LOS
Non-LOS and
Mobile
Bit Rate
32-134 Mbps
Up to 75
Mbps
Up to 75
Mbps
Up to 15 Mbps
Cell Radius
1-3 miles
3-5 miles
3-5 miles
1-3 miles

8. Architecture

9. Physical Layer
• Five physical layer modes
Designation
WirelessMAN-SC
802.16e
10 -66 GHz
WirelessMAN-SCa
802.16d
Applicability
Below 11GHz
Licensed bands
WirelessMAN-OFDM
Below 11GHz
Licensed bands
WirelessMAN-OFDMA
Below 11GHz
Licensed bands
WirelessHUMAN
Below 11GHz
Licensed-exempt bands

10. Orthogonal Frequency Division
Multiplexing (OFDM)
• Multiplexing technique that divides the channel into
multiple orthogonal sub channels
• Input data stream is divided into several sub streams
of a lower data rate and each sub stream is modulated
and simultaneously transmitted on a separate sub
channel
• High spectral efficiency, resilient to interference, and
low multi-path distortion

11. Conventional FDM and OFDM

12. Orthogonal Frequency Division
Multiple Access (OFDMA)
• Multiple-access/multiplexing scheme
– multiplexing operation of data streams from multiple users
– Dynamically assign a subset of sub channels to individual
users
• Wireless MAN-OFDMA based on scalable OFDMA
(SOFDMA)
– Support scalable channel bandwidths from 1.25 to 20 MHz

13. MAC Layer
Service Specific Convergence
Sublayer
MAC Common Part Sublayer
Interface to higher layer
protocols, classifies incoming
data, etc.
Core MAC functions (i.e.,
scheduling, connection
maintenance, fragmentation),
QoS control
Privacy Sublayer
Encryption, authentication,
secure key exchange

14. Network Operation

15. Applications
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1.
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4.
According to WiMax Forum it supports 4
classes of applications:
Multi-player Interactive Gaming.
Video Conference.
Web Browsing and Instant Messaging.
Media Content Downloads.

16. Advantage
• Low cast.
• It can support:
NLOS(non line of set)&LOS.
Mesh Network.
Point to Multipoint.
Handoff Technique.
• Coverage:50Km.
• Max Data Rate:70Mpbs.

17. Disadvantage
• Interference issues.
• It is not work proper in weather.

18. Features
• Use wireless link with microwave or millimeter wave
radios.
• Use licensed spectrum
• Use point-to-multipoint architecture, tower-mounted
antennas
• Provide broadband and QoS, data transmissions.

19. Conclusions
• WiMax becomes the dominant Wireless MAN in
the world market.
• The end-users will have to be extremely easy to
install.
• Focus is too often on technologies
– Subscribers pay for services, not
technologies
– Broadband capabilities are important, but
bandwidth is not the only meter to assess service

20. Querries?

21. Thank u.

22. References
• IEEE802.16
• Alcatel White Paper: WiMAX, making
ubiquitous high-speed data services a reality
• Intel White Paper: Understanding WiMAX
and 3G for Portable/Mobile Broadband
Wireless
• WiMAX Forum: www.wimaxforum.com
• http://en.wikipedia.org/wiki/WiMax