Wimax Final Report

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ACKNOWLEDGEMENT

It is a matter of great pleasure and privilege for me to present this report. First and

foremost I would like to express my deep sense of gratitude to Mr. Sourabh Porwal,

(Seminar Guide), Mr. Saurabh Porwal (Seminar Incharge) Mrs. Meena Kushwaha

(Seminar Incharge) for their support at every stage of this report. Right from the inception

of the idea to its ultimate realization their flow of ideas and concepts helped me to prepare

this report.

I am very grateful to Mr. Rajeev Mathur (HOD of ECE Dept.) for his timely guidance

and innumerable suggestions. He has been very helpful in boosting my confidence to

carry out this report successfully.

I also want to express my gratitude to our Director Dr. A.N. Mathur who has directly or

indirectly been part of this endeavor of mine. I greatly appreciate his spirit and

enthusiasm.

Lastly I would fail in my duties if I do not thank my parents for their continuous help and

encouragement.

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CANDIDATES DECLARATION

I hereby declare that the work, which is being presented in the Seminar Report, entitled WiMax in partial fulfillment for the award of Degree of Bachelor of Technology in

Department of Electronics and Communication Engineering submitted to the Department

of Electronics and Communication Engineering, Geetanjali Institute of Technical Studies,

Udaipur, Rajasthan Technical University is a record of my own investigations carried

under the Guidance of Mr. Sourabh Porwal , Lecturer, Department of ECE.

I have not submitted the matter presented in this Seminar Report any where for the award

of any other Degree.

Vipin Ranka

Dept. Of ECE

RTU Roll No.08EGIEC114

Counter Signed by

Mr. sourabh Porwal

Lecturer

Department of ECE

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PREFACE

As per the curriculum of RAJASTHAN TECHNICAL UNIVERSITY, KOTA for

bachelors degree in Engineering I have completed the investigation on wireless

networkl under the guidance of Mr.Sourabh Porwal.

This report contains the study of WiMax.

WiMAX is an IP based, wireless broadband access technology that provides performance

similar to 802.11/Wi-Fi networks with the coverage and QOS (quality of service) of

cellular networks. WiMAX is also an acronym meaning Worldwide Interoperability for

Microw ave Access (WiMAX). WiMAX is a wireless digital communications system, also known as IEEE 802.16, that is

intended for wireless "metropolitan area networks". WiMAX can provide broadband

wireless access (BWA) up to 30 miles (50 km) for fixed stations, and 3 - 10 miles (5 - 15

km) for mobile stations. In contrast, the WiFi/802.11 wireless local area network standard

is limited in most cases to only 100 - 300 feet (30 - 100m).

With WiMAX, WiFi-like data rates are easily supported, but the issue of interference is

lessened. WiMAX operates on both licensed and non-licensed frequencies, providing aregulated environment and viable economic model for wireless carriers.

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CONTENTS

1 Introduction 1

2 Wireless Networking 2

2.1 Wireless Standards 3

3 What is Wi-Fi 4

3.1 How Wi-Fi 6

3.2 Wi-Fi Technology Standards 9

3.3 Advantages of Wi-Fi 10

3.4 Disadvantage of Wi-Fi 11

4 What is WiMAX? 13

4.1 How WiMAX works 14

4.2 Backhaul 16

4.3 Types of WiMAX 17

4.4 Advantages of WiMAX 19

4.5 Disadvantages of WiMAX 19 5 WiMAX Versus Wi-Fi 20

5.1 Uses of Wi-Fi versus WiMAX 22

5.2 Capacity of Wi-Fi versus WiMAX 22

5.3 Technical difference of the two

Standards 23

6 Conclusion 26 7 References 27

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INTRODUCTION

WiMAX is not a technology, but rather a certification mark, or 'stamp of approval' given to equipment that meets certain conformity and interoperability tests

for the IEEE 802.16 family of standards. A similar confusion surrounds the term Wi-

Fi, which like WiMAX, is a certification mark for equipment based on a different set

of IEEE standards from the 802.11 working group for wireless local area networks

(WLAN). Neither WiMAX, nor Wi-Fi is a technology but their names have been

adopted in popular usage to denote the technologies behind them. This is likely due to

the difficulty of using terms like 'IEEE 802.16' in common speech and writing.

Fig 1: Wi-Fi and WiMAX logo

WiMAX and Wi-Fi are both wireless broadband technologies, but they differ

in the technical execution. Wi-Fi was developed to be used for mobile computing

devices, such as laptops, in LANs, but is now increasingly used for more services,

including Internet and VoIP phone access, gaming, and basic connectivity of

consumer electronics such as televisions and DVD players, or digital cameras. On the

other hand WiMAX was developed as a standards-based technology enabling the

delivery of last mile wireless broadband access as an alternative to cable and DSL

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WIRELESS NETWORKING

How Internet can be made available in remote places of our county with cost effective

manner?

By using wireless networks

Imagine the possibility of an ambulance with high quality wireless connections to a

hospital, vital information of injured patient can be send to hospital instantly fromaccident sport so that the hospital would be ready for treating the patient by the time

he/she arrives there. The term wireless networking refers to technology that enables

two or more computers to communicate using standard network protocols but

without network cable.Wireless networks recognize the radio waves and microwaves

to maintain communication channel between computers

Basic type of wireless networks can be classified into

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Ad hoc network (Peer to Peer): each device is equipped with wireless

Cards and they can setup a network very quickly with out any

infrastructure.

Infrastructure based network: The device communicate each other

through a base station.

2.2 Wireless Standards

IEEE 802 refers to a family of IEEE standards dealing with local area networks and

metropolitan area networks. More specifically, the IEEE 802 standards are restricted

to networks carrying variable-size packets. (By contrast, in cell-based networks data

is transmitted in short, uniformly sized units called cells. Isochronous networks,

where data is transmitted as a steady stream of octets, or groups of octets, at regular

time intervals, are also out of the scope of this standard.) The number 802 was

simply the next free number IEEE could assign, through 802 is sometimes

associated with the date the first meeting was held February 1980

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What is Wi-Fi?

Wi-Fi is a trademark of the Wi-Fi Alliance that manufacturers may use to brandcertified products that belong to a class of wireless local area network (WLAN)

devices based on the IEEE 802.11 standards, which is by far the most widespread

WLAN class today. Because of the close relationship with its underlying standard, the

term Wi-Fi is often used as a synonym for IEEE 802.11 technology

Wi-Fi is for Wireless Fidelity, essentially a set of standards for transmitting data over

a wireless network. Wi-Fi allows you to connect to the net at broadband speeds

without cables, as long as you have the right equipment and, in most cases, a regular

internet service provider and a Wi-Fi account.

Fig 4: WLAN standard

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USES:

1. Internet Access

A Wi-Fi enabled device such as a personal computer, video game console,

mobile phone, MP3 player or personal digital assistant can connect to the Internet

when within range of a wireless network connected to the Internet. The coverage of

one or more (interconnected) access points called hotspots can comprise an

area as small as a few rooms or as large as many square miles. Coverage in the larger

area may depend on a group of access points with overlapping coverage.

In addition to private use in homes and offices, Wi-Fi can provide public access at

Wi-Fi hotspots provided either free-of-charge or to subscribers to various commercial

services. Organizations and businesses - such as those running airports, hotels and

restaurants - often provide free-use hotspots to attract or assist clients.

In internet access we have

1.a City-wide Wi-Fi

In the early 2000s, many cities around the world announced

plans for city-wide Wi-Fi networks. This proved to be much more difficult

than their promoters initially envisioned with the result that most of these

projects were either cancelled or placed on indefinite hold. A few were

successful, for example in 2005, Sunnyvale, California became the first city

in the United States to offer city-wide free Wi-Fi

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1.b Campus-wide Wi-Fi

Carnegie Mellon University built the first wireless Internet

network in the world at their Pittsburgh campus in 1994, long before Wi-Fibranding originated in 1999. Most campuses now have wireless Internet.

2. Direct Computer-to-Computer Communication

Wi-Fi also allows communications directly from one computer to

another without the involvement of an access point. This is called the

ad-hoc mode of Wi-Fi transmission.

3. Future Directions

As of 2010 Wi-Fi technology has spread widely within business and

industrial sites. In business environments, just like other environments,

increasing the number of Wi-Fi access points provides network

redundancy, support for fast roaming and increased overall network-

capacity by using more channels or by defining smaller cells. Wi-Fi

enables wireless voice-applications

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3.1 How Wi-Fi works?

Wi-Fi uses one or more Wireless Access Points (WAP) (can be compared to cell

phone towers) and clients (WiFi Adapters) (comparable to cell phones) to transfer

data by the use of radio waves. These Access points serve as base station for variouswi-fi enabled equipments.

The access point broadcasts its SSID (The network name) and clients can identify it

and decide to connect. If two or more access point uses same SSID, the client will

automatically connect to the access point that has better signal strength.

The electronics on the receivers end are called WiFi adapters and it can be either in -

built to the device itself or can be in the form of an external device like a USB stick.

Wi-Fi networking can transfer data at a rate ranging from 2Mbps 108 Mbps and for

a distance from several meters to several hundred meters. The signal strength depends

on the distance from access points and the type of Wi-Fi technology in use.

Figure below shows how Wi-Fi works. The description of the numbers shown in the

figure helps to understand the working of Wi-Fi.

Fig 5: How does Wi-Fi work

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1: Wi-fi uses antennas around which wi-fi "hotspots" are created. The hotspots are

outlets equipped to receive the radiowaves that power wireless networking. Until

recently, wi-fi has been confined to more than 10,000 hot-spots in cafes, bars and

airport lounges. But various projects are under way to set up city-wide zones, where a

series of antennas are installed in the streets, on lampposts or street signs. The

hotspots around them together create a much wider area of coverage. Norwich has a

mesh network which links each lamppost antenna to the next creating a seamless wi-fi

hotspot around the centre of the city.

2: The source internet connection is provided by a PC or server to which the antennas

are connected either wirelessly or via a cable.

3: Some mobile phones and personal digital assistants (PDA) now have Wi-Fi chips

installed. With mobile phones, this means conventional networks can be bypassed and

inexpensive long-distance calls made over the web (using Voice over Internet

Protocol, VoIP).

4: Many laptops and handheld computers now come with built-in wi-fi connectivity;

it is also possible to add wi-fi to your computer with a special card that plugs into a

port on your laptop.

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3.2 Wi-Fi Technology Standards

IEEE 802.11 Standards Wi-Fi

The first version of Wi-Fi standard 802.11 uses 2.4GHz spectrum to transfer

data. The operating speeds were around 1-2Mbps. This version was released in 1997.

IEEE 802.11a (Wi-Fi a)

Released in 1999, this version of Wi-Fi uses 5GHz frequency spectrum and

are capable of providing 10Mbps speed.

IEEE 802.11b (Wi-Fi b)

This was the modified format to tackle the issues of 802.11a version, where

multiple access points were required for stable reception. The major change was that

this version uses 2.4GHz frequency spectrum. 802.11b version works at a speed of

11Mbps and was widely accepted at the time of release.

IEEE 802.11g (Wi-Fi g)

The most widely accepted Wi-Fi networking format of modern times. Wi-Fi g

can deliver speeds up to 54Mbps and can support many clients. This version works on

2.4GHz spectrum. This version was released in 2003.

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IEEE 802.11n (Wi-Fi n)

The newest version, currently in draft can deliver speeds up to 108Mbps and

has a signal range of several hundred meters. This technology uses multiple input

multiple output pipelining and hence can use multiple antennas for better signal

strength.

Table 1: IEEE 802.11 Radio Link Interfaces

3.3 Advantages of Wi-Fi

No Wires Required Wi-Fi technology allows you to deploy networks

without the hassle of wiring up your computers. Since Wi-Fi does not use

wires, you can easily set up wireless networks even outdoors.

Standard Maximum bit Channels Frequency Radio

rate provided band techniques 802.11 2 Mbps 3 2.4 GHz FHSS or DSSS

802.11 b 11 Mbps 3 2.4 GHz DSSS

802.11 a 54 12 5 GHz OFDM

802.11 g 54 3 2.4 GHz OFDM

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Wi-Fi Chipsets are Cheap Wi-Fi adapters are now built-in with laptops; hence you

dont need to add any extra device to receive Wi -Fi signals.

New Wi-Fi Devices Many new devices (Camera / Cell phones / Personal Media

Players / Media Storage Devices ) support Wi -Fi technology. You can easily

transfer files from these devices without any wires. Some of the newer devices even

provide direct internet uploading from the device itself.

Backward Compatibility Wi-Fi versions working on same operating spectrum are

backward compatible. Hence if you have an old Wi-Fi device, it can work on your

newest Wi-Fi access point.

Data Encryption Wi-Fi supports different types of advanced encryption technologies

to securely encrypt your data. This means, you can use wifi for transferringconfidential data on a secured network.

Wifi Hotspots Businesses can provide Wi-Fi hotspots (Public Wi-Fi area) to

increase the customer base. Many universities, Airports and retail markets started

providing public WiFi services.

3.5 Disadvantages of Wi-Fi

Signal Strength Limitation As wifi uses radio waves, the signal strength is

affected by the presence of obstacles. Hence wifi works better on outdoors

than indoors.

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Data Transfer Limit According to latest Wi-Fi n draft, this technology can

seamlessly deliver speeds upto 108Mbps, but we already have better

technology (Gigabit LAN) that

can deliver speeds up to 1000 Mbps. Hence Wi-Fi technology in present state

are not suitable for fast connectivity needs like network gaming.

Uses Shared Frequency Spectrum The operating frequency of 2.4GHz is

used by Bluetooth devices, Microwave ovens, Cordless Phones and many

other home appliances. Hence there is a chance of interference or network

crowding for the Wi-Fi signals, which can adversely affect the quality of

signal.

Un-Secured WAP(Wireless Access Point) can result in malicious usage. Even

though many routers / access points comes with security features, they areseldom used. The result is that anyone with a Wi-Fi adapter with in the range

can use your connection without your knowledge.

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What is WiMAX?

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 createdby WiMAX forum, the consortium promoting this standard. The term WiMAX is

derived from the phrase Worldwide Interoperability for Microwave Access.

The WiMAX system was designed to popularize broadband access the way cell

phones have done to our telephone communication system. WiMAX may replace the

old form of broadband access through landlines, DSL and cable in future.

The WiMAX system can be considered as an efficient alternative to Wi-Fi, where the

un-avoidable limitation was the distance of coverage. WiMAX solves this problem by

using higher frequency range to deliver more data to a larger distance.

Fig 6: WMAN standard

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USES:

The bandwidth and range of WiMAX make it suitable for the following potential

applications:

Providing portable mobile broadband connectivity across cities and

countries through a variety of devices

Providing a wireless alternative to cable and DSL for " last mile " broadband

access.

Providing data, telecommunications (VoIP) and IPTV services ( triple play ).

Providing a source of Internet connectivity as part of a business continuity

plan.

Providing a network to facilitate machine to machine communications, such

as for Smart Metering

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4.2 How WiMAX Works?

WiMAX, just like Wi-Fi uses radio waves to transfer data. The important difference is

that WiMAX uses two spectrums of frequencies to provide two kinds of wireless

broadband access services. (Mobile WiMAX & Fixed WiMAX)

The WiMAX system has two parts; one is the WiMAX tower (similar to a cell phone

tower) and a receiver. The receiver can be of two types depending on the device. It

can be an embedded device just like our wi-Fi receivers or it can be advanced

hardware equipment with dedicated antennae.

The WiMAX tower connects to internet through regular mediums of connectivity like

fibre optic cable or T1 lines. It can also connect with other WiMAX towers using

radio link.

This additional line-of-sight connectivity is the biggest advantage of WiMAX.

Technically, this is called the backhaul system. Thus by installing multiple towers,

WiMAX can easily provide broadband access to large number of people.

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4.2 BACKHAUL

Backhaul is actually a connection system from the Access Point (AP) back to theprovider and to the connection from the provider to the network. A backhaul can set

out any technology and media provided; it connects the system to the backbone. In

most of the WiMAX deployments circumstances, it is also possible to connect

several base stations with one another by use of high speed backhaul microware

links. This would also allow for roaming by a WiMAX subscriber from one base

station coverage area to another, similar to roaming enabled by cellular phone.

Fig 8 : A WiMAX TOWER

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4.3 Types of WiMAX

WiMAX delivers broadband access in two ways depending on the operationalfrequencies.

Fixed WiMAX Mobile WiMAX

o Fixed WiMAX

802.16-2004 is also known as 802.16d, which refers to the working party that has

developed that standard. It is sometimes referred to as "Fixed WiMAX," since it has no

support for mobility.

In this form, WiMAX tower works more like an efficient & powerful Wi-Fi

access point. The frequency range of operation is 2GHz 11GHz, almost similar

to Wi-Fi frequencies.

In this mode of operation, the data transfer occurs between WiMAX tower and the

internal mobile receivers. As the frequency of operation is low, there is a limitationin area of coverage. According to theory, this type of WiMAX can only deliver up

to 6-7 KMs.

The same effect can be analogized to cell phone tower system. That is the same

reason, why we need more number of towers for wide area coverage.

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o Mobile WiMAX

802.16e-2005 , often abbreviated to 802.16e, is an amendment to 802.16-2004. It introduced

support for mobility, among other things and is therefore also known as "Mobile WiMAX".

In this form, the receiver requires dedicated antennae properly installed in the line-of-sight of

WiMAX tower. These types of connections are stronger and stable as it uses 66GHz frequency

spectrum to carry more data. This mode of operation can deliver broadband services to about

50KM radius.

Table 2: Summary of 802.16 Radio Link

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4.4 Advantages of WiMAX

Large Area of Coverage: As WiMAX can deliver high-speed internet to large

distance, it is very well suited to provide broadband access to remote areas of

the world.

Scalability: As earlier mentioned, by using backhaul feature of WiMAX, you

can set up large number of WiMAX towers in matter of days as opposed to

wiring that requires proper planning and heavy labor.

In Built QoS: Quality of Service mechanisms in WiMAX allows mission-

critical services to run smoothly even if there is lack of resources. This way,

mission critical services are allowed to run at full priority when everything is

busy.

Multi-User Connectivity: A single WiMAX tower can connect to 100 client

receivers. These clients can of different modes of operation

4.6 Disadvantage of WiMAX

Specialized Equipment Required: For utilizing full functionality of WiMAX,

you need specialized hardware with dedicated antennae.

Limited Date Rate: When compared to other modes of broadband

connectivity, for example, fibre optic cables and satellite internet, WiMAX is

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still slow.

Bandwidth Shared Among Users: WiMAXs another drawback is that it

distributes the bandwidth among users. This means, you will experience slowdown when there are more uses in the base.

Speed Decrease over Large Distance: Because of bit rate errors happening at

large distance, WiMAX system is forced to use lower bit rates at these

distances. This means less data transfer rate.

Interference May Affect Connectivity: As the WiMAX uses radio waves, it is

susceptible to interference caused by other equipments.

Rain can affect Connectivity: As fixed WiMAX requires line-of-sight radio

link, heavy rain can disrupt the entire link.

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WiMAX versus Wi-Fi

Comparing WiMAX to Wi- Fi is akin to comparing apples to oranges. Initially its

easy to see why the comparison would exist, as most people think WiMAX is merely

a more robust version of Wi-Fi. Indeed they are both wireless broadband

technologies, but they differ in the technical execution and ultimately their business

case is very different. In addition to the technical differences that exist, the

marketplace difference is that equipment is more or less non-existent for WiMAX and

certainly not geared towards a residential environment with very high pricing to be

expected. It will take at least 2 years to see equipment of mass market uptake pricing.

WiMAX will not be commercially available until the second half of 2005, and even

then at a very controlled level. This is primarily due to standardization issues. In fact,

it wont be until 2006 that a robust production and implementation will happen due to

the ramp-up period for manufacturers. This is certainly one challenge to the

widespread adoption of WiMAX. Additionally, WiMAX will have issues of pricing,

and will remain far more expensive than Wi-Fi. WiMAX will be primarily adopted by

businesses to replace or displace DSL, and offices that want to cover a lot of territory

without entering the world of endless repeaters that are necessary with the 802.11

technologies. It will take some time (2 years) for WiMAX to significantly reduce its

price-point for residential uptake. WiMAX will not displace WiFi in the home

because WiFi is advancing in terms of speed and technology. Each year brings a new

variant to the 802.11 area with various improvements.

Additionally, for commercial deployment, frequency allocation will be an issue. With

the three dominant communications players controlling the best frequencies, it will be

hard to get the type of traction needed with the remaining companies operating in the

frequencies available. WiMAX will become extremely robust and displace WiFi as

the deployment of choi ce for commercial deployments, but that wont even begin

until the end of 2006. Based upon the number of public

hotspots already deployed, WiMAX will not be chosen to replace those asthey are up and

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running adequately and personnel involved understand how to work with the

technology. The business case does not exist at the hotspot level. Where it may exist

is for wider free use deployments such as city deployments (free ones) and other

government sponsored or carrier sponsored (with ultra inexpensive pricing for

consumers) deployments. If this happens then its not only WiFi that will be displaced,

but cable and DSL will also lose a percentage of their subscriber base. What will

cause the displacement is the consumers proven desire for a bund led package.

5.1 Uses of Wi-Fi vs. the uses of WiMAX

Wi-Fi is mostly used to provide a Wi-Fi enabled device such as a computer, cellphone or PDA an Internet/LAN connection when in proximity of an access point. Wi-

Fi can also be used to create a mesh network. Wi-Fi also allows connectivity in peer-

to-peer mode, which enables devices to connect directly with each other.

WiMAX on the other hand with its higher bandwidth and longer reach is planned to

be used for connecting Wi-Fi hotspots with each other and to other parts of the

Internet, providing a wireless alternative to cable and DSL for last mile (last km)

broadband access, providing high-speed mobile data and telecommunications services

(4G).

5.2 Capacity of Wi-Fi vs. WiMAX

Both the Wi-Fi and the WiMAX connectivity are dependent on the distance of two

connection points (antennas). Keeping this in mind we can see that when using Wi-Fi

with the IEEE 802.11g standard, which is the most common standard used on todays

equipment, the data rate is around 54 Mbit/s and the range indoors are around 30

meters. This range and data rate is changed with the conditions of the area used andthe line of sight of devices used.

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WiMAX will deliver 70 Mbit/s, 112 kilometers in theory. But these numbers

will change according to conditions, expected values are 10Mbit/s in a 2 KM area.

5.3 Technical differences of the two standards

5.3.1 Media Access Controller (MAC) Layer

In Wi-Fi MAC uses contention access all subscriber stations that wish to

pass data through a wireless access point (AP) are competing for the AP's attention on

a random interrupt basis. This can cause subscriber stations distant from the AP to be

repeatedly interrupted by closer stations, greatly reducing their throughput. This

makes services such as Voice over IP (VoIP) or IPTV, which depend on an essentially

constant Quality of Service (QoS) depending on data rate and interruptibility, difficult

to maintain for more than a few simultaneous users.

In contrast, the 802.16 MAC uses a scheduling algorithm for which the

subscriber station need compete once (for initial entry into the network). After that it

is allocated an access slot by the base station. The time slot can enlarge and contract,

but remains assigned to the subscriber station which means that other subscribers

cannot use it. The 802.16 scheduling algorithm is stable under overload and over-

subscription (unlike 802.11). It can also be more bandwidth efficient. The scheduling

algorithm also allows the base station to control QoS parameters by balancing the

time-slot assignments among the application needs of the subscriber stations.

5.3.2 Physical layer

In Wi-Fi except for 802.11a, which operates at 5 GHz, Wi-Fi uses the

spectrum near 2.4 GHz, which is standardized and unlicensed by international

agreement, although the exact frequency allocations vary slightly in different parts of

the world, as does maximum permitted power. However, channel numbers are

standardized by frequency throughout the world, so authorized frequencies can be

identified by channel numbers. The frequencies for 802.11 b/g span 2.400 GHz to

2.487 GHz. Each channel is 22 MHz wide yet there is a 5 MHz step to the next higher

channel. The maximum number of available channels for Wi-Fi enabled devices is 13

for Europe, 11 for North America and 14 for Japan.

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Whereas in WiMAX, the original WiMAX standard (IEEE 802.16) specified

WiMAX for the 10 to 66 GHz range. 802.16a, updated in 2004 to 802.16-2004 (also

known as 802.16d), added specification for the 2 to 11 GHz range. 802.16d (also

known as "fixed WiMAX") was updated to 802.16e in 2005 (known as "mobile

WiMAX"). and uses scalable orthogonal frequency-division multiplexing (OFDM) as

opposed to the OFDM version with 256 sub-carriers used in 802.16d. More advanced

versions including 802.16e also bring Multiple Antenna Support through Multiple-

input, multiple-output communications. This brings potential benefits in terms of

coverage, self installation, power consumption, frequency re-use and bandwidth

efficiency. 802.16e also adds a capability for full mobility support. The WiMAX

certification allows vendors with 802.16d products to sell their equipment as WiMAX

certified, thus ensuring a level of interoperability with other certified products, as long

as they fit the same profile.

Most interest will probably be in the 802.16d and .16e standards, since the

lower frequencies suffer less from inherent signal attenuation and therefore give

improved range and in-building penetration. Already today, a number of networks

throughout the World are in commercial operation using certified WiMAX equipment

compliant with the 802.16d standard.

5.3.3 Network layer

Both standards are designed to be used with the first and the second layers of

the OSI model. Both the standards can be used with a variety of different network

layers, including IP.

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In general we can say, even though both WiMAX and Wi-Fi works on radio

waves, there are differences in their operations and functionalities.

WiMAX Wi-Fi

(802.16) (802.11)

Range long distance system, high- short-range system,

speed broadband access to broadband access to several

several KMs hundred feet

Data Rate 70Mbps 54Mbps

Scalability

highly scalable

Not scalable

Local Network cannot use it for your own work for private networks

private network

Spectrum Licensing requires spectrum licensing does not require such a

license

Table 4: the comparison of WiMAX and Wi-Fi

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Conclusion

Even though WiFi technology has many disadvantages, properly configured WAPs

will give you the best wireless connectivity you can get. Latest developments show

that WiFi would be embedded in to most of the consumer devices, thus enabling us

to wirelessly interact and there by improve the productivity and entertainment

experience.

As WiMAX delivers high-speed internet through wireless medium, the cost of

implementing broadband access to remote parts of world are very low. Because of

the same reason, we believe WiMAX have huge potential to become the worlds

popular broadband access method in near future.

Wi-Fi and WiMAX are complementary. WiMAX network operators typically provide

a WiMAX Subscriber Unit which connects to the metropolitan WiMAX network andprovides Wi-Fi within the home or business for local devices (e.g., Laptops, Wi-Fi

Handsets, smart phones ) for connectivity. This enables the user to place the WiMAX

Subscriber Unit in the best reception area (such as a window), and still be able to use

the WiMAX network from any place within their residence.

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31/31

REFERENCES

Stallings, William, Data and Computer Communications, Pearson-Prentice

Hall, 7th Ed., USA, 2004.

http://en.wikipedia.org/wiki/Wimax http://en.wikipedia.org/wiki/Wifi http://www.voip-news.com/news/features/wifi-vs-wimax-050806/

http://www.mobilein.com/WiFi_vs_WiMax.htm http://en.wikipedia.org/wiki/IEEE_802.11 http://en.wikipedia.org/wiki/IEEE_802.16 http://en.wikipedia.org/wiki/OSI_model http://changelog.ca/topic/WiMax http://www.cisco.com/en/US/netsol/ns341/ns396/ns177/networking_solutions_w

hite_pap er0900aecd801aa448.shtml

http://www.tutorialsweb.com/wimax/wimax.htm