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WiMAX is a digital wireless data communication system that can deliver high-speed broadband services up to a large distance of 50KMs.The name WiMAX was created by WiMAX forum, the consortium promoting this standard. The term WiMAX is derived from the phrase Worldwide Interoperability for Microwave Access.
2. Internet Connections
Three traditional ways to connect Internet:
1)Dial-up access – It is an Internet connection that will be established by
using a modem which act as data transfer medium when user initiates dial
up connection.
2)Broadband access -This refers to high-speed data transmission in
which a single cable(DSL,cable modem) can carry a large amount of data
at once.
3)WiFi access - Wi-Fi refers to wireless networking technology that
allows computers and other devices to communicate over a wireless signal.
3. IEEE 802.16 Specifications
• Range - 30-mile (50-km) radius from base station
• Speed - 70 megabits per second
• Line-of-sight not needed between user and base station
• Frequency bands - 2 to 11 GHz and 10 to 66 GHz (licensed and
unlicensed bands)
• Defines both the MAC and PHY layers and allows multiple PHY-layer
specifications.
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4. What is WiMAX ?
• WiMAX is short for “Worldwide Interoperability for
Microwave Access”
• WiMAX is technically also known as “IEEE 802.16”
• WiMAX is a wireless communications standard designed for
creating Metropolitan Area Networks(MANs).
• It is similar to the Wi-Fi standard, but it can broadcast as big as
3,000 square miles.
5. Architecture of WiMAX
A WiMAX system consists of two parts:
• WiMAX receiver:
The receiver could be a small box or PCMCIA card, or they could
be built into a laptop the way Wi-Fi access is today.
• WiMAX tower:
It can provide cover to a very large area as big as 3,000 square
miles.
8. Wi-MAX Type 802.16 802.16a/Rev d 802.16e
Completed Dec 2001 802.16a Jan 2003
802.16 Rev d June 2004
Mid 2005
Spectrum 10 – 66 GHz 2 – 11 GHz 2 – 6 GHz
Application Backhaul Wireless DSL and Backhaul Mobile Internet
Channel Conditions Line of Sight only Non – Line of sight Non – Line of Sight
Bit rate 32 – 134 Mbps at 28 MHz
channelization
Up to 75 Mbps at 20 MHz
channelization
Up to 15 Mbps at 5 MHz channelization
Modulation QPSK 16 QAM and 64 QAM OFDM 256 sub carriers
QPSK 16 QAM and 64 QAM
Scalable OFDMA
Mobility Fixed Fixed Pedestrian Mobility / Regional roaming
Channel Bandwidth 20, 25 and 28 MHz Selectable channel between 1.5 and
20MHz
Same as 802.16a with UL sub
channels to conserve power
Typical Cell Radius 1 – 3 miles. 4 – 6 miles. Maximum range 30 Miles
based on tower height, antenna gain
and power transmit.
1 – 3 Miles
10. Maximum Speed Supported
• WiMAX 802.16 - 280Mbps
• 3G - up to 2 Mbps
• Wi-Fi - up to 600 Mbps
• Mobile-Fi -- up to 80 Mbps
11. Coverage Area
• WiMAX 802.16a/Rev d - 30 Miles Max
• WiMAX 802.16 - 1 – 3 Miles
• WiMAX 802.16e - 1-3 Miles.
• 3G and Mobile-Fi - 5 Miles
• Wi-Fi 802.11 - 300 feet
• Wi-Fi router - 30 Feet
12. Airwave
• 3G and Mobile-Fi 802.20 are the licensed ones
• WiMAX 802.16 can be either Licensed or Unlicensed
• Wi-Fi 802.11 is an unlicensed one.
Channel Condition
• The WiMAX 802.16, 3G and Wi-Mobile 802.20 is optimized for
Outdoor Non- Line of Sight
• Wi-Fi 802.11 is Line of Sight based.
13. Quality of Service
WiMAX 802.16
• Grant request MAC
• Designed to support voice and video from the start
• supports differentiated service levels and centrally enforced QoS
Wi-Fi 802.11
• Contention – based MAC
• No guaranteed QoS
• Standard Cannot guarantee latency for voice or video
• No allowance for differential levels of service on a per user basis
• Proposed 802.11e QoS standard is prioritization only
14. Bandwidth
WiMAX
802.16 - 20-28 MHz
802.16a/Rev d - 1.5 -210MHz
802.16e - 3.6MHz
Wi-Fi 802.11 - 20MHz
Wi-MAX 802.165 supports Maximum 5.0 bps/Hz
Wi-Fi 802.11 Supports only up to a maximum 2.7 bps/Hz.
15. Scalability
For WiMAX 802.16
• the channel bandwidths can be chosen by the operator for the
sectorization and scalable independent of bandwidth with
1.5MHz to 20MHz width channels
• MAC also supports thousands of users
where as Wi-Fi 802.11 has only wide 20MHZ channels and MAC
only supports tens of users.
16. Advantages
• WiMAX 802.16 is surely an advanced technology when compared
with the other technologies with more
Bandwidth
Bit rate
Coverage area
Performance
Quality of service and secure too.
17. Disadvantages
• Interference with Bluetooth wireless communication
• The cost of equipment is really high and it has not yet widely
used.
• Power-consuming technology
• High installation
• Signal interruption in bad weather
18. Present research work on WiMAX
• WiMAX2 is the present ongoing development in the WiMAX
versions.
• That is to increase the speed of existing WiMAX network.
• Currently existing WiMAX versions provides minimum of 30 to
40 megabits per second of speed.
• But the goal of the WiMAX2 is to get 100 Mbit/s for mobile
devices and 1 Giga bits per second fixed type of WiMAX devices
and 4G for next generation mobile network.