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Chapter II

Literature Review

2.1 Introduction

This chapter shows that the idea of this project could be carry out according to the

objectives and aims and able to produces a good result. There are a few of software which

we could utilize to test the outcome of this project and numbers of wireless router that can

select from. However, there will be a need to consider the pros and cons of the devices

that was picked. Although there are a few places are supported by Wi-Fi likes COE foodcourt, BA building ground floor, and COIT ground floor, however, places like lecturers

room, classroom, meeting room, and waiting areas are not covered. It is not easy to get

those areas cover as they are highly affected by distance, obstructions, or interference

which could affect the network performances.

2.2 WiFi Standards

2.2.1 Definition of Wireless Fidelity

Wi-Fi is the industry name forwireless LAN (WLAN) communication technology related

to the IEEE 802.11 family of wireless networking standards. To some, the term Wi-Fi is

synonymous with 802.11b, as 802.11b was the first standard in that family to enjoy

widespread popularity and was pushed by the Wi-Fi Alliance, a trade group that

pioneered commercialization of the technology. Today, however, Wi-Fi can refer to any

of the established standards: 802.11a, 802.11b, 802.11g and 802.11n. Below are the

further details of the standard of Wi-Fi.

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2.2.2 802.11

In 1997, the Institute of Electrical and Electronics Engineers (IEEE) created the first

WLAN standard. They called it 802.11 after the name of the group formed to oversee its

development. This is the very first development of WiFi. Unfortunately, 802.11 only

supported a maximum network bandwidth of 2 Mbps. For this reason, ordinary 802.11

wireless products are no longer manufactured.

2.2.3 802.11b

IEEE expanded on the original 802.11 standard in July 1999, creating the 802.11b

specification. 802.11b supports bandwidth up to 11 Mbps, comparable to traditional

Ethernet. 802.11b uses the same unregulated radio signaling frequency (2.4 GHz) as the

original 802.11 standard. Being unregulated, 802.11b gear can incur interference from

microwave ovens, cordless phones, and other appliances using the same 2.4 GHz range.

However, by installing 802.11b gear a reasonable distance from other appliances,

interference can easily be avoided.

TABLE 2.1 Pros and Cons of 802.11b

Pros of 802.11b lowest cost; signal range is good and not easily obstructed

Cons of 802.11b slowest maximum speed; home appliances may interfereon the unregulated frequency band

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2.2.4 802.11a

While 802.11b was in development, IEEE created a second extension to the original

802.11 standard called 802.11a. In fact, 802.11a was created at the same time. Due to its

higher cost, 802.11a is usually found on business networks whereas 802.11b serves better

at the home market. 802.11a supports bandwidth up to 54 Mbps and signals in a regulated

frequency spectrum around 5 GHz. This higher frequency compared to 802.11b shortens

the range of 802.11a networks. The higher frequency also means 802.11a signals have

more difficulty penetrating walls and other obstructions. Because 802.11a and 802.11b

utilize different frequencies, the two technologies are incompatible with each other.

TABLE 2.2 Pros and Cons of 802.11a

Pros of 802.11a fast maximum speed; regulated frequencies prevent signal

interference from other devices

Cons of 802.11a highest cost; shorter range signal that is more easily

obstructed

2.2.5 802.11g

In 2002 and 2003, WLAN products supporting a newer standard called 802.11g emerged

on the market. 802.11g attempts to combine the best of both 802.11a and 802.11b.

802.11g supports bandwidth up to 54 Mbps, and it uses the 2.4 Ghz frequency for greater

range. 802.11g is backwards compatible with 802.11b, meaning that 802.11g access

points will work with 802.11b wireless network adapters and vice versa.

TABLE 2.3 Pros and Cons of 802.11g

Pros of 802.11g fast maximum speed; signal range is good and not easilyobstructed

Cons of 802.11g costs more than 802.11b; appliances may interfere on the

unregulated signal frequency

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2.2.6 802.11n

The newest IEEE standard in the Wi-Fi category is 802.11n. It was designed to improve

on 802.11g in the amount of bandwidth supported by utilizing multiple wireless signals

and antennas instead of one. When this standard is finalized, 802.11n connections should

support data rates of over 100 Mbps. 802.11n also offers better range over earlier Wi-Fi

standards due to its increased signal intensity. 802.11n equipment is backward compatible

with 802.11g gear.

TABLE 2.4 Pros and Cons of 802.11n

Pros of 802.11n fastest maximum speed and best signal range; more

resistant to signal interference from outside sources

Cons of 802.11n Standard is not yet finalized; costs more than 802.11g; the

use of multiple signals may greatly interfere with nearby

802.11b/g based networks.

However, not every IEEE 802.11 compliant device is certified by the Wi-Fi

Alliance, which may be because of certification costs that must be paid for each certifieddevice type. The Alliance created the branding Wi-Fi CERTIFIED to reassure consumers

that products will interoperate with other products displaying the same branding.

A Wi-Fi enabled device such as a PC, video game console, mobile phone, MP3

playerorPDA connect network to each other and to the Internet when within range of a

wireless networkconnected to the Internet from any Wi-Fi hotspot, and digital cameras

can transfer images wirelessly. It can make access publicly available at Wi-Fi hotspots

provided either free of charge or to subscribers to various providers.

Organizations and businesses such as airports, hotels and restaurants often provide

free hotspots to attract or assist clients. Wi-Fi also allows connectivity in peer-to-peer

(wireless ad hoc network) mode, which enables devices to connect directly with each

other.

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2.3 Wireless Access Point

Wireless access points for known as (APs or WAPs) are specially configured nodes on

wireless local area networks (WLANs) and act as a central transmitter and receiver of

WLAN radio signals. Access points are usually used in home or small business networks

are generally small, dedicated hardware devices featuring a built-in network adapter,

antenna, and radio transmitter. Access points support Wi-Fi wireless communication

standards. Although very small WLANs can function without access points in so-called

"ad hoc" or peer-to-peer mode, access points support "infrastructure" mode. This mode

bridges WLANs with a wired Ethernet LAN and also scales the network to support more

clients. Older and base model access points may allow a maximum of only 10 or 20 users

but many newer access points support up to 255 clients at a time. This prove theadvancement of the technology day by day.

2.4 Wireless Router

A wireless router is a network device that performs the functions of a routerbut also

includes the functions of a wireless access point. It is commonly used to allow access to

the Internet or a computer networkwithout the need for a cabled connection. It can

function in a wired LAN (local area network), a wireless only LAN or a mixed

wired/wireless network. Most current wireless routers have the following characteristics:

LAN ports, which function in the same manner as the ports of a network

switch

A WAN port, to connect to a wider area network. The routing functions are

filtered using this port. If it is not used, many functions of the router will be

bypassed.

Routers which incorporate a DSL-modem or a cable-modem and a Wi-Fi access

point, often set up in homes and other premises, provide Internet-access and

internetworking to all devices connected (wirelessly or by cable) to them.

2.5 Wireless Range Extender

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A wireless range extender increases the distance over which a WLAN signal can spread,

overcoming obstacles and enhancing overall network signal quality. Several different

forms of wireless range extenders are available. These products are sometimes called

"range expanders" or "signal boosters." The Linksys WRE54G (compare prices) 802.11g

Wireless Range Expander is shown above.

A wireless range extender works as a relay or networkrepeater, picking up and

reflecting WiFi signals from a network's base router or access point. The network

performance of devices connected through a range extender will generally be lower than

if they were connected directly to the primary base station.

A wireless range extender connects wirelessly to a WiFi router or access point.

However, due to the nature of this technology, most wireless range extenders work only

with a limited set of other equipment. Check the manufacturer's specifications carefully

for compatibility information.

2.6 Wireless Adapter

Most new laptops and many new desktop computers now come with built-in wireless

transmitters. If the laptop doesn't have one, wireless adapter can be plugs into the PC card

slot orUSB port. Desktop computers can use USB adapters, or buy an adapter that plugs

into the PCI slot inside the computer's case. Many of these adapters can use more than

one 802.11 standard.

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FIGURE 2.1 Wireless adapters can plug into a computer's PC card slot

FIGURE 2.2 Wireless adapter plug-in using USB port

Once, the wireless adapter and the drivers was installed that allow it to operate,

the computer should be able to automatically discover existing networks. This means that

when you turn your computer on in a Wi-Fi hotspot, the computer will inform you that

the network exists and ask whether you want to connect to it. If you have an older

computer, you may need to use a software program to detect and connect to a wireless

network.

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2.7 Multi-antenna types

MIMO is stands for multiple input multiple outputs and is also a method of utilizing

multiple antennas for wireless communications. For wireless networking, MIMO

technology appears in some Wi-Fi routers, greatly enhancing their capability over single-

antenna routers. MIMO Wi-Fi routers utilize the same network protocols and signal

ranges that non-MIMO routers do.

FIGURE 2.3 Understanding of SISO, SIMO, MISO and MIMO

The MIMO products achieve higher performance by more aggressively

transmitting and receiving data over Wi-Fi channels. MIMO signaling technology can

increase network bandwidth, range and reliability at the potential cost of interfering with

other wireless equipment.

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FIGURE 2.4 MIMO Communications

The exact number of antennas utilized in a MIMO Wi-Fi router can vary. Typical

MIMO routers contain three or four antennas instead of the single antenna that is standard

in all earlier forms of consumer Wi-Fi routers. MIMO is a key element of the 802.11n

Wi-Fi networking standard.

2.8 Survey of System Dimensioning Approach and Technology

2.8.1 How a Wi-Fi works

A computer's wireless adapter translates data into a radio signal and transmits it using an

antenna. A wireless routerreceives the signal and decodes it. The router sends the

information to the Internet using a physical, wired Ethernet connection. The process also

works in reverse, with the router receiving information from the Internet, translating it

into a radio signal and sending it to the computer's wireless adapter. The radios used for

Wi-Fi communication are very similar to the radios used for walkie-talkies, cell phones

and other devices. They can transmit and receive radio waves, and they can convert 1s

and 0s into radio waves and convert the radio waves back into 1s and 0s. But Wi-Fi radios

have a few notable differences from other radios.

They transmit at frequencies of 2.4 GHz or 5 GHz. This frequency is considerably

higher than the frequencies used for cell phones, walkie-talkies and televisions. The

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higher frequency allows the signal to carry more data. They use 802.11 networking

standards, which come in several choices.

Other 802.11 standards focus on specific applications of wireless networks, like

wide area networks (WANs) inside vehicles or technology that lets you move from one

wireless network to another seamlessly. Wi-Fi radios can transmit on any of three

frequency bands. Below is the diagram how the Wi-Fi works.

FIGURE 2.5 How WiFi works

2.8.2 Setting up Wireless Network

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If there are several computers networked at home, you can create a wireless network with

a wireless access point. If several computers that are not networked, or want to replace

the Ethernet network, wireless router is needed. This is a single unit that contains:

A port to connect to yourcable orDSL modem

A router

An Ethernet hub

A firewall

A wireless access point

FIGURE 2.6 Wireless Router

A wireless router uses an antenna to send signals to wireless devices and a wire to

send signals to the Internet. Once you plug in your router, it should start working at its

default settings. Most routers let you use a Web interface to change your settings. You

can select:

The name of the network, known as its service set identifier (SSID) -- The

default setting is usually the manufacturer's name.

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Most routers use channel 6 by default. If you live in an apartment and your

neighbors are also using channel 6, you may experience interference.

Switching to a different channel should eliminate the problem.

Many routers use a standard, publicly available sign-on, so it's a good idea to

set your own username and password.

Security is an important part of a home wireless network, as well as public

Wi-Fi hotspots. If you set your router to create an open hotspot, anyone who

has a wireless card will be able to use your signal.

2.8.6 How to position the Wireless Device for best performance

The performance of a Wi-Fi home network greatly depends on signal strength of the

wireless routerorwireless access point (base station). If a given wireless falls out of

range of the base station signal, obviously that network connection will fail or drop.

Users situated near the edge of the network range will likely experience intermittent

dropped connections. But even when stays within range consistently, its network

performance can still be highly affected by distance, obstructions, or interference.

To position the wireless equipment for optimal network performance, follow these

guidelines. First and foremost, don't settle prematurely on a location for the wireless

access point or router. Try placing the device in several different promising locations.While trial-and-error may not be the most scientific way to find a good spot for your

equipment, it is often the only practical way to assure the best possible Wi-Fi

performance. Strive to install the wireless access point or router in a central location. If

there is only one wireless user, installing the base station near the user is best. For

WLANs with multiple wireless users, find a good compromise position.

Next, avoid physical obstructions whenever possible. Any barriers along the "line

of sight" between client and base station will degrade a Wi-Fi radio signal. Plaster or

brick walls tend to have the most negative impact, but really any obstruction including

cabinets or furniture will weaken the signal to some degree. Obstructions tend to reside

closer to floor level; therefore, some folks prefer to install their wireless access point /

router on or near the ceiling. Avoid reflective surfaces whenever possible. Some Wi-Fi

signals literally bounce off of windows, mirrors, metal file cabinets and stainless steel

countertops, lessening both network range and performance. Install the wireless access

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point or router at least 1 m (3 feet) away from other home appliances that send wireless

signals in the same frequency range. Such appliances include some microwave ovens,

cordless telephones, baby monitors, and home automation equipment like X-10 devices.

Any appliance that transmits in the same general range as 802.11b or802.11g (2.4 GHz)

can generate interference.

Likewise, install the unit away from electrical equipment that also generates

interference. Avoid electric fans, other motors, and fluorescent lighting. If the best

location that can find is only marginally acceptable, consider adjusting the base station

antennas to improve performance. Antennas on wireless access points and routers can

usually be rotated or otherwise re-pointed to "fine tune" Wi-Fi signaling. Follow the

specific manufacturer's recommendations for best results. If using these guidelines and

still cannot find a suitable location for the wireless gear, there are alternatives. For

example, replace and upgrade the base station antenna or also install a Wi-Fi repeater

(often called a "range extender" or "signal booster.") Finally, in extreme cases, configure

a second base station to extend the range of your WLAN will be needed as well.

2.9 Application Needed For the Project

2.9.1 Floor plan

Overall, the whole UNITEN position on the world atlas is able to trace by the freesoftware Google Earth. This map provides the general view of the project site and as a

guideline to draw the area of internet coverage in UNITEN area. Moreover, the floor plan

of the each building in UNITEN, example BM, BW, BA and BN building are available at

Pusat Pengurusan Harta (PPH) under the management of Mr. Michael Chan Kim Liang.

A letter of request for the floor plan of which site, has to be produce and to be certify by

Dr. Cheah Cheng Lai.

2.9.2 Ekahau HeatMapper - The Free Wi-Fi Coverage Mapping Site Survey Tool

Ekahau HeatMapper is a free software tool for quick and easy coverage mapping of Wi-Fi

(802.11) networks. It's the only free, easy-to-use tool that shows, on a map, the wireless

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network coverage in your home or small office. It supports 802.11n, as well as a/b/g

wireless device and locates all access points. HeatMapper uses built-in wireless network

adapter, therefore, all is needed a Windows-based laptop with wireless.

2.9.3 Qcheck free Software Testing Throughput

Qcheck is a troubleshooting utility from Ixia which able to measures the response time of

the IP networks and stimulates real application flows across the network to test

connectivity and performance. In this software, it gauge network throughput with

different type of traffic like Transmission Control Protocol (TCP), User Datagram

Protocol (UDP), Real-time Transport Protocol (RTP). It was mainly use too check the

throughput function. Below is the structure of the Qcheck software.

FIGURE 2.7 Qcheck software tool

2.10 Signal strength testing

One of the ways to check the signal strength is use the Operating system utility

(Microsoft Windows) or other network operating systems contain a built in utility to

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monitor wireless network connection status. In the Network Connections section of

Control Panel, opening the Status window of the Wireless Network Connection icon

reveals a Signal Strength meter. This meter shows up to five green bars representing the

current strength on a quality scale from "Very Low" (1 bar) to "Excellent" (5 bars).

FIGURE 2.8 Wifi Signal 2.7.1 FIGURE 2.9 Microsoft Window Signal Strength

Next is the Wifi Signal 2.7.1 software which is use to test bandwidth and speed of

the connection. The Wi-Fi Signal can do a digital readout of the Wi-Fi signal strength and

it can also show you the name of the network that the computer connected to, or the

signal strength as a raw percentage.