Wimax vsWi-fi

WiMAX Versus Wi-Fi

A Seminar Report

Submitted by

Reshma MR

In partial fulfillment for the award of the degree

Of

BACHELOR OF TECHNOLOGY

In

COMPUTER SCIENCE AND ENGINEERING

SCHOOL OF ENGINEERING

COCHIN UNIVERSITY OF SCIENCE & TECHNOLOGY

COCHIN-682022

August 2010

DIVISION OF COMPUTER ENGINEERING

SCHOOL OF ENGINEERING

COCHIN UNIVERSITY OF SCIENCE AND TECHNOLOGY

COCHIN– 682022

CERTIFICATE

Certified that this is a bonafied record of the Seminar work entitled

“WIMAX versus Wi-Fi”

done by

RESHMA.M.R

of the VIIth semester, Computer Science and Engineering in the year 2010 in partial

fulfillment of the requirements to the award of Degree of Bachelor of Technology in

Computer Science Engineering of Cochin University of Science and Technology.

Dr.David Peter Mr.Sudheep Elayidom

Head of the department Seminar Guide

ACKNOWLEDGEMENT It is with greatest pleasure and pride that I present this report before you. At this moment of triumph, it would be unfair to neglect all those who helped me in the successful completion of this seminar.

First of all, I would like to place myself at the feet of God Almighty for his everlasting love and for the blessings & courage that he gave me, which made it possible to me to see through the turbulence and to set me in the right path. I would also like to thank our Head of the Department, Mr. David Peter S for all the help and guidance that she provided to me.

I am grateful to my guide, Mr. Sudheep Elayidom.M , for his guidance and whole hearted support and very valued constructive criticism that has driven to complete the seminar successfully.

I would take this opportunity to thank my friends who were always a source of encouragement.

ABSTRACT

Wi-Fi, which stands for “Wireless Fidelity”, is a radio technology that networks computers so they connect to each other and to the Internet without wires .Users can share documents and projects, as well as an Internet connection among various computer stations, and easily connect to a broadband Internet connection while traveling. By using a Wi-Fi network, individuals can network desktop computers, laptops and PDAs and share networked peripherals like servers and printers. A Wi-Fi network operates just like a wired network, without the restrictions imposed by wires. Not only does it enable users to move around be mobile at home and at work , it also provides easy connections to the Internet and business networks while traveling .The technologies used in this field are one of the best in the wireless space . It is fairly easy to set up a Wi-Fi enabled network at home or a small office. WiMAX, meaning Worldwide Interoperability for Microwave Access, is a telecommunications technology that provides wireless transmission of data using a variety of transmission modes, from point-to-point links to portable internet access [citation needed]. The technology provides up to 75 Mbits/ symmetric broadband speed without the need for cables. The technology is based on the IEEE 802.16 standard (also called Broadband Wireless Access). The name “WiMAX” was created by the WiMAX Forum, which was formed in June 2001 to promote conformity and interoperability of the standard. The forum describes WiMAX as a standards-based technology enabling the delivery of last mile wireless broadband access as an alternative to cable and DSL”.s

Chapter No. Title Page No.

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

4.3 Types of WiMAX

16

17

4.4 Advantages of WiMAX 19

4.5 Disadvantages of WiMAX 19

5

5.1

5.2

5.3

WiMAX Versus Wi-Fi

Uses of Wi-Fi versus WiMAX

Capacity of Wi-Fi versus WiMAX

Technical difference of the two

standards

20

22

22

23

6 Conclusion 26

7 References 27

Fig no. FIGURES Page no:

1 Wi-Fi and WiMAX logo 1

2 Wireless network 2

3 802 Wireless standards 3

4 WLAN Standards 4

5 How Wi-Fi works 7

6 WMAN Standards 13

7 How WiMAX works 15

8 A WiMAX tower 16

List of Tables

Tab no. Tables Page no 1 IEEE 802.11 Radio Link Interface 10

2 Summary of 802.16 Radio Link 19

3 Mobile Standards Compared 24

4 Comparison WiMAX and Wi-Fi 25

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CHAPTER 1

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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CHAPTER 2 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 from accident 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

FIG 2: Wireless Network between two computers

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Basic type of wireless networks can be classified into 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.

2.1 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

Fig 3: 802 wireless standards

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CHAPTER 3

What is Wi-Fi?

Wi-Fi is a trademark of the Wi-Fi Alliance that manufacturers may use to brand certified

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-Fi branding 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

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 various wi-fi enabled equipments.

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The access point broadcasts it’s 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 receiver’s 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 works

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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.

IEEE 802.11n (Wi-Fi n)

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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.

Standard Maximum bit

rate

Channels

provided

Frequency

band

Radio

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

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.

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

don’t 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 transferring confidential

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.

3.4 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.

• 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

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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 are seldom 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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CHAPTER 4

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 created by 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

4.1 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.

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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.

Fig 7: How WiMAX works

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4.2 BACKHAUL

Backhaul is actually a connection system from the Access Point (AP) back to the provider 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 operational frequencies.

• 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 limitation in 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.

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".

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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

4.5 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 still slow.

• Bandwidth Shared Among Users: WiMAX’s another drawback is that it distributes the

bandwidth among users. This means, you will experience slow down 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.

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• 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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CHAPTER 5

WiMAX versus Wi-Fi

Comparing WiMAX to Wi-Fi is akin to comparing apples to oranges. Initially it’s 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 won’t 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 choice for commercial

deployments, but that won’t even begin until the end of 2006. Based upon the number of public

hotspots already deployed, WiMAX will not be chosen to replace those as they 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 consumer’s proven desire for a bundled

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, cell phone 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 today’s 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 and the 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.

Table 3: Mobile Standards Compared

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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

(802.16)

Wi-Fi

(802.11)

Range long distance system, high-

speed broadband access to

several KMs

short-range system,

broadband access to several

hundred feet

Data Rate 70Mbps 54Mbps

Scalability highly scalable Not scalable

Local Network cannot use it for your own

private network

work for private networks

Spectrum Licensing requires spectrum licensing does not require such a

license

Table 4: the comparison of WiMAX and Wi-Fi

Wi-MAX Versus Wi-Fi

Division of Computer Science, SOE CUSAT 26

CHAPTER 6

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 world’s 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 and provides 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.

Wi-MAX Versus Wi-Fi

Division of Computer Science, SOE CUSAT 27

CHAPTER 7

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_white_pap

er0900aecd801aa448.shtml

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