Wi-MAX Versus Wi-Fl

CHAPTER 1

INTRODUCTION

WÌMAX is not a technology, but rather a ceitification mark, or stamp of approval given

to equipment that meets certain conformity arki intemperability tests for the IEEE 802.16 family

of standards. A similar confusion surrounds the term Wi-Fi, which like W1MAX. 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 (VLAN). Neither WiMAX, nor Wi-Fi is a

technology but their names have been adopted in popular usage to denote the technologies

behind tbem This is likely due to tbe difficulty of using terms like IEEE 802 16 in common

speech and writing.

 

Fig 1: Wi-Fl and WIMAX logo

 

WiMAX and Wi-Fi are both wireless broadband technologies, but t1y 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 tbe other hand WiMAX was developed as a standards-

based techrilogy enabling the delivery of last mile wireless broadband access as an alternative to

cable and DSL

 


WIRELESS NETWORKING

How Internet can be made available in rente places of our county with cost effective manner?

By using wireless networks Imagine the possibility of an ambulance with high quality wireless conictions to a hospital.

ital 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 helshe arrives there. The term

wireless networking refrrs to techrlogy that enables two or nre computers to coniniunieate

using standard network protocols but without network cableWireless networks recognize the

radio waves and microwaves to maintain communication channel between computers


FIG 2: Wireless Network between two computers

Basic type of wireless networks can be classified into

Ad hoc nehork (Peer (o Peer): each device is equipped with wireless Cards and they

can setup a network very quickly with out any infrastn.icture.

• Jnfrastructure based neiwork: The device communicate each otber through a base

station.

2i Wireless Standards

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

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

rtworks carrying variable-size packets. (By contrast, in cell-based networks data is transmitted

in short. uniibrmly 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 standani 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

RFIIV ___

Radao Frequency


Fig 3: 802 wireless standard

What is Wi-Fl?

Wi-Fl is a trademark of the Vi-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 tbe most widespread WLAN class today. Because of the

close relationship with its underlying standard, the term Vi-Fi is often used as a synonym for

IEEE 802.11 technology

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

network Wi-Fl allows you to connect to the net at bmadband speeds without cables, as long as

ou have the right equipment and, in most cases, a regular ‘nternet service provider and a Wi-Fi

account.

êicb.

Fig 4: WLAN standard


Wi-MAX Versus Wi-Fl

t SES:

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 Interrt. 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 additn to private use in hones aii offices. Wi-Fi can pnwide public access at Wi-Fl

Ixtspots provided cuber free-of-charge or to subscribers to various commercial services.

Organizations and businesses - such as tbsc running airports, hotels arid restaurants - often

provide free-use hotspots to attract or assist chants.

In internet access we have

l.a City-vide Wi-Fl

In the early 2000s. many cities arourki the world announced plans for city

wide Wi-Fi rktworks. This proved to be much more difficult than their promaters initially

envisioned with the resu It thai 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

Wi-MAX Versus Wi-Fl

1.b Campus-wide Wi-Fl

Carnegie Mellon Univerity built the first wireless Internet rtwork in the

world at their Pittsburgh campus in 1994. long befon Wi-Fi branding originated in 1999. Most

campuses now have wireless Interrt.

2. Direct Computer-to-Computer Communication

XVi-Fi also allows communications directly from one computer to another without

the involvement of an access point. ThLS is called the ad-hoc mode of Wi-Fl

transmission.

3. Future Directions

As of 2010 Wi-Fl technology has spread w1ely within business and industrial

sites. In business envimnments. just like other environments. increasing the

number of Wi-Fi access points prov kies network redundancy. support for fast

roaming and incia.sed overall network-capacity by using more channels or by

defining smaller celLs. Wi-Fi enables wireless voice-applications

3.1 How Wi-Fl works’?

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

and clients (WiFi Adapters) (comparable to cell phones) to transtèr data by the use of radio

waves. These Access points serve as base station for various wi-fi enabled equipments.

The access point broakasts it’ s SSID (The netork name) and clients can identify it and decide

to conrct. 1f two or nre access point uses sane 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 itselt’ or can be in the form of an external device like a IJSB stick.

rpj networking can transfer data at a rate ranging from 2Mbps — 108 Mbps and for a distance

from several nters 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 Vi-Fi works. Tbe description of tbe numbers shown in the figure helps

to understand the working of Wi-Fi.

FIg 5: How does Wi-Fi works


Wi-MAX Versus Wi-Fl

1: Wi-ft uses antennas around which wi-fl “hotspots” are cnated. The hotspots are outlets

equipped to receive the radiowaves thai power wireless networking. Until ncently. wi-fi has

been contined to more than 10.0(X) hot-spots in cafes, bars and airport lounges. But various

projects are under way to set up city-wide zones. where a series ot’ 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 amund the centre of the city.

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

connected either wire!esslv or via a cable.

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

With mobile phones, this locatis 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 cone with built-in wi-fl connectivity: it is also

possible to add wi-f. to your computer with a special card that plugs into a port on your laptop.


Wi-MAX Versus Wi-Fl

3.2 W i-Fi Technology Standards

• IEEE 802.11 Standards Wi-Fi

The first version of Wi-Fl 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.lla(Wi-Fia)

Released in 1999. this version of Wi-Fi uses 5GHz frequency spectrum and are capable

of providing 10Mbps speed.

• IEEE 802.llb(Wi-Fi b)

This was the modified format to tackle the issues of 802.1 Ia version. when multiple

access points were required for stable reception. The major change was that this version uses

2.4GHz fnqueiy spectrum. 802.llb version works at a speed of 11Mbps arid was widely

accepted at the time of release.

. IEEE 802.1 1g (XVi-Fi g)

The most widely accepted XVi-Fi networking format of rmdern times. XVi-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 l02.11n (Vi-Fi n)

Wi-MAX Versus Wi-Fl

The ne’est 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 Maximuin Channels Freqincy Radio

rate provided batid techniques

802.11

802.11 b

802.11 a

2 Mbps f 3

11 Mbps 3

54 12

2.4 GI-Iz

2.4GHz

5 GI-Iz

FHSS or DSSS

DSSS

OFDM

802.11 g

54 3

2.4 Gl-Iz

OFDM

Table 1: IEEE 802.11 Radio Link Interfaces

3.3 Advantages of Wi-Fl

. No Wires Required — Wi-Fi technology allows you to deploy networks ithout the hassle

of wiring up your computers. Since W i-Fi does not use wires, you can easily set up
wireless networks even outdoors.

Wi-MAX Versus Wi-Fl

. Wi-Fl Chip sets are Cheap — Wi-Fl adapters are rw built-in with laptops: hence ou

don’t need to add any extra device to receive Wi-Fl signals.

. New Wi-Fl Devices — Many new devices (Camera / Cell phones / Personal Media Plars

/ Media Storage Devices ...) support Wi-Fi technology. You can easily transfer files from

these devices without any wires. Son of the newer devices even provide direct internet

uploading from the device itself.

. Backward Compatibility — Wi-Fl versions working on same operating spectrum are

backward compatible. Here if you have an old XVi-Fi device, it can work on your newest

W i-Fi access point.

. Data Encryption — Wi-Fl supports different types of advanced encryption technologies to

secunly encrypt your data. This nans. you can use wifi for transferring confidential

data on a secured network.

. Wifi Hotspots — Busiisses can provide Wi-Fl hotspots (Public Wi-Fl area) to increase

the customer base. Many universities. Airports and retail markets started providing public

WiFi services.

3.4 Disadvantages of ‘i-Fi

. Signal Strength Limitation — As wifi uses radio waves, the signal strength is affected by

the preserve of obstacles. Hence wifi works better on outdoors than indoors.

. Data Transfer Limit — According to latest Wi-Fl n draft, this techrlogy can seamlessly

deliver speeds upto 108Mbps. but we already have better technology (Gigabit LAN) that

 

Wi-MAX Versus Wi-Fl

can deliver speeds up to 1000 Mhps. Hence Wi-Fi technology in present state are not

suitable for fast connectivity needs like network gaming.

. Uses Shared Frequeney Spectrum — The operating frequery of 2.4GHz is used by

B luetooth devices. Microwave ovens. Cordless Phones and many other home appliances.

Hence there is a chance of inter ferenee or network crowding for the Wi-Fl 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 »ur connection

without your knowledge.

What is WiMAX?

WIMAX is a digital wireless data communication system that can deliver high-speed broadband

services up to a large distance of 5OKMs.The name WIMAX was created by WÌMAX forum, the

consortium promoting this staftiard. The term WIMAX is derived from the phrase Workiwide

Interoperability for Microwave Access.

The WIMAX system was designed to popularize broadband access the way cell phones have

done to our telephone communicatk)n system. WiMAX may replace the oki form of broadband

access through landlines. DSL and cable in future.

The WiMAX system can be considered as an efficient alternative to Wi-Fi. wbere the un

avoidable limitation was the distance of coverage. WiMAX solves this problem by using higher

frequency range to deliver nk)re data to a larger distance.

•uuq

Fig 6: WMAN standard

Wodd*4d rd.rop.rabdìty Sor bhaow.v. Accaea

Wireesa AeropoI(an Ara NetworI

w


US ES:

The bandwidth and range of WÌMAX make it suitable for the following potential applications:

. Providing portable mobile bruadband connectivity across cities and cou nines thruugh a

variety ot’ 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 piovide two kinds of wireless biuadband 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 nceiver can be of two types depending on tbe device. It can be an embedded

device just like our wi-Fl nceivers or il can be advanced hardware equipment with dedicated

antennae.

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

cable or Ti lines. It can also connect with other WiMAX towers using radio link.


Wi-MAX Versus Wi-Fl

This additional line-of-sight comctivity is the biggest advantage of WIMAX. Technically, this

is called the backhaul system. Thus by installing multiple towers. WIMAX can easily provide

broadbalkl access to large number of people.

Fig 7: [low ‘jj works


Wi-MAX Versus Wi-Fl

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

ndia provided; it connects the system to the backbone. In nst of tbe WIMAX deployments

circumstances, it is also possible to connect several base stations with one another by use ot’

high speed backhaul nucrowan 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 S: A WiMAX TOWER

Wi-MAX Versus Wi-Fl

4.3 Types of WIMAX

WiMAX delivers broadband access in two ways depending on the operational frequencies.

. Fixed WIMAX

. Mobile WiMAX

o Fixed WIMAX

N02.16-2004 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 & powerlùl Wi-Fl access point. The

frequency range of operation is 2G1-Lz — IIGI-Iz. alnst similar to Vi-Fi frequencies.

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

nubile receivers. As the frequency of operation is low, then is a limitation in area of coverage.

Acconling to theory. this type of WiMAX can only deliver up to 6-7 KMs.

The sanie effect can be analogized to cell phone tower system. That is the same reason, why we

need more number of towers for wide are-a coverage.

o Mobile WiMAX

H02.16e-2005. often abbreviated to 802.16e. is an amendment to 802.16-2004. It introduced

support for mobility, among otlkr things and is therefore also known as “Mobile WiMAX’.

Wi-MAX Versus Wi-Fl

4.4 Advantages of Wil%IAX

. Large Area of Coverage: As WIMAX can deliver high-speed Internet to large distance, it

is ery well suited to provide broadband access to nmote are-as of the work!.

. Scalability: As earlier nntk)ned. 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

pmper planning and heavy labor.

. In Built QoS: Quality of Service nchanisms in WiMAX allows mission-critical services

to run sniothly even if ttre 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 c-an connect to IOU client receivers.

These clients can of different nudes 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 nudes of broadband connectivity, for

example, fibn optic cables and satellite internet. WIMAX is still slow.

. Bandwidth Shand Anng 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 tbese distances. This means
less data transfer rate.

 

. Interkrere May Afft Connectivity: As the WIMAX uses radio waves. it is susceptible

to interfereixe caused by other equipments.

. Rain can affect Connectivity: As fixed WiMAX requires line-of-sight radio link, heavy

rain can disrupt the entire link.

Wi-MAX Versus Wi-Fl

CHAPTER 5

WiMAX versus XVi-Fi

comparing WiMAX to Wi-Fl is akin to comparing apples to oranges. Initially ks easy to see

why the comparison would exist, as nst people think WIMAX is merely a more robust version

of Wi-Fl. Indeed tbey are both wireless broadband techrxlogies. but they differ in the technical

execution and ultimately their business case is very different. In addition to the technical

differeres that exist. tbe marketplace difference is that equipment is nxre or less non-existent

tir 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 standaniization 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 vario us improvements.

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

dominant communications players controlling the best frequencins, it will be han.1 to get the type

of traction needed with the remaining companies operating in the frequeriies 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

botspots already deployed. WiMAX will not be chosen to replace those as they are up and


Wi-MAX Versus Wi-Fl

running adequately and personnel involved understand how to work with the technology. The

business case does not exist at tbe ltspot level. Where it may exist is for wider free use

&plo3ments sneh as city deployments (free ones) and other government sponsored or carrier

sponsored (with ultra inexpensive pricing for consunrs) deployments. I this happens tben its

it 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-Fl vs. the uses of WiMAX

Wi-Fi is mostly used to provide a Wi-h enabled device such as a computer. cell phone or

[-‘DA an Internet/LAN connection when in proximity of an access point. XVi-Fi can also be used

to create a ns1i network. XVi-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 XVi-Fi hotspots with each other and to other parts of tbe Internet. providing a

wireless alternative to cable and DSL for last mile (last km) broadband access, providing high-

speed mobile data and teleconmiu nicat ions sen’ ices (4G).

5.2 Capacity of Wi-Fl vs. WIMAX

B4)th the Wi-Fl 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 standani used on today’s equipnnt. 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.

Wi-MAX Versus Wi-Fl

WIMAX will deliver 70 Mbitls. 112 kilometers in theory. But these numbers will change

according to conditions, expected values are lOMbit/s in a 2 KM area.

5.3 Technical differences of the two standards

53.2 Media Access Controller (MAC) Laver

In Wi-Fl MAC uses contention access — all subscriber stations that wish to pass data

through a wireless access point (AP) are competing for the APs attention on a random interrui

basis. This can cause subscriber stations distant from the AP to be repeatedly interrupted by

closer stations, greatly reducing their thmughput. This makes services such as Voice over IP

(V0IP) or IPTV, which depend on an essentially constant Quality of Service (Q0S) 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 tine 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 tine-slot assignments among the application needs of the subscriber stations.

5.3.2 Physical laver

In Wi-Fl except for 802. lia, which operates at 5 GHz. W i-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 frequeneies for 802.11 b/g

span 2.400 GI-Iz 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-Fl enabled devices is

13 for Eumpe, Il for North Anrica and 14 for Japan.


Wi-MAX Versus Wi-Fl

Whereas in WIMAX. the original WiMAX standard (IEEE 802.16) specified WIMAX for

the 10 to 66 GI-Iz range. 802.16a. updated in 2004 to 802.16-2004 (also known as 802.16d).

added specification for the 2 to 11 G l-la range. 802. l6d (aLso known as “fixed WiMAX”) was

updated to 802.16e in 2005 (known as “mobile WiMAX”). ari uses scalable orthogonal

frequency-division multiplexing (OFI)M) 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, sell installation, power consumption. fnquency re-use and baedwidth

efficiency. 802.16e also adds a capability for lÙll mobility support. The WÌMAX 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 atil .16e standards, since the lower

frequencies suffer less from inherent signal attenuation and therefore give improved range and

in-building penctration. Already today. a number of’ networks througbut the World are in

commercial operation using certified WiMAX equipment comphant with tbe 802. 16d standard.

5.3.3 Network laver

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 differrnt network layers. including IP.

Wi-Fl: WiMAX:


Wi-MAX Versus Wi-Fl

CHAPTER 6

Conclusion

Even though WiFi technology has many disadvantages, propedy configured WAPs will give

ou the best winIess 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 sanie 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 met.ropolitan 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 tbe user to place tbe WiMAX Subscriber Unit in the best reception

are-a (such as a window), and still be able to use tbe WiMAX network from any place within

their residence.

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