1.0
INTRODUCTION
Cellphones usually work as a go-to source for staying notified about breaking news and
community incidents, getting from place to place, conducting transactions, and cruising life
events such as finding a new job or learning more about a health issue. It is also a medium of
communication and entertainment. Cellphones are being used from the start of a person's day to
the end. They are being used as an alarm clock, calendar, and meeting organizer. Cellphones are
being used to run businesses, order foods, book tickets, order medicines, sharing media and files.
These options were not always in the palm of their hands. Today, a staggering 2,617 times a day
are spent rubbing phones. More people have access to a cell phone than a toilet in the entire
planet. Today, a staggering 2,617 times a day are spent rubbing phones. More people have access
to a cell phone than a toilet in the entire planet. In an average year, people spend just under 800
hours on their mobile phones (that's over a whole month!). And with these figures rising all the
time, it's no surprise that the last ten years have been labeled as the 'decade of the Cellphones'
When Martin Cooper, a senior engineer at Motorola, called a rival telecommunications company
and informed them that he was speaking from a mobile phone, he created history.
CHAPTER TWO
2.0
Literature Review:
Leah Li V. Echiverri, PhD, is the instructor. The advancement of technology since the turn of the
20th century is unmatched, and the creation of the cell phone must be the most significant. Cell
phones have essentially revolutionized how we interact and live today. However, there must be the
greatest advertising between phones and smartphones. With the introduction of various
applications, a cell phone is no longer only a tool for communication; it now has a multitude of
uses in our daily lives and, thanks to teens' curiosity, including that of us college students, makes
up an unmatched large market of Smartphone users.
Unofficial learning is supported by cell phones for a group of undergraduate students in the United
Arab Emirates (UAE), according to a 2011 report. Despite the small number of academic
applications, it was discovered during the investigation that these applications are quite helpful for
their research. The study makes it evident that the majority of participants engaged in a range of
informal activities, including publishing and replying to questions on an online forum, creating
wiki entries, and sharing data between devices. The use of mobile applications to promote learning
in museum settings is also explained by a number of related considerations (e.g. Sharples et al.
2007; Pierroux 2008). Many of these outcomes make it possible for a cell phone to support data
transfer. Motivate students to continue their unstructured learning, to finish. Although sometimes
we need to study or work on our phones, it is stilled, not a basic need for us to handle. There are
just less than 8% of smartphone users who will spend their time mostly on official applications
according to Rosen (2013)'s research. Anyhow, we prefer to pastime to work, so in our spare time,
we would like to use the other two categories of applications.
2.1
EVOLUTION OF CELLPHONES TECHNOLOGY
Martin Cooper of Motorola, shown here in a 2007 reenactment, made the first publicized
handheld mobile phone call on a prototype DynaTAC model on 3 April 1973.
In the early days of radio engineering, a mobile handheld radio telephone service was
anticipated. A patent application for a "pocket-size folding telephone with a very thin carbon
microphone" was made in 1917 by the Finnish inventor Eric Tigerstedt. Cellular phones' earliest
antecedents included analog radio transmissions from trains and ships. Following World War II,
numerous nations started competing to produce really portable telephone equipment. Beginning
with early zeroth-generation (0G) services like Bell System's Mobile Telephone Service and its
successor, the Improved Mobile Telephone Service, the advancements in mobile telephony may
be followed in succeeding "generations." These 0G systems were exceedingly expensive, did not
support many simultaneous calls, and were not cellular.
The DynaTAC 8000X from Motorola. It became the first in 1983.
The Motorola DynaTAC 8000X, it was the first commercially viable portable cell phone when it
was introduced in 1983.
Affordable mobile communications and gadgets like the vehicle phone were made possible by
the development of cellular networking, information theory, and large-scale integration (LSI)
MOS technology. John F. Mitchell and Martin Cooper of Motorola presented the first handheld
cellular mobile phone in 1973, utilizing a 2-kilogram handset (4.4 lb). Nippon Telegraph &
Telephone (1G) launched the first automated commercial cellular network in Japan in 1979. The
Nordic Mobile Telephone (NMT) system was simultaneously introduced in Denmark, Finland,
Norway, and Sweden in 1981 as a result. Later, in the early to mid-1980s, a number of other
nations did likewise. While using analog cellular technology, these first-generation (1G) systems
could allow many more simultaneous calls. The DynaTAC 8000x was the first portable mobile
phone to be made available for purchase in 1983.
Radiolinja introduced the second-generation (2G) GSM-based digital cellular technology in
Finland in 1991. As a result, the established 1G network providers faced competition from the
new players in the market. At the CEPT ("Conférence Européenne des Postes et
Telecommunications," European Postal and Telecommunications conference), the GSM standard
was proposed as a European initiative. Following the technical viability of the Franco-German
R&D collaboration, 13 European nations signed a Memorandum of Understanding in 1987 and
committed to launching a commercial service by 1991. The GSM (=2G) standard's initial
iteration contained 6,000 pages.
Thomas Haug and Philippe Dupuis received the 2018 James Clerk Maxwell medal from the
IEEE and RSE for their contributions to the first digital mobile phone standard. Over 5 billion
individuals in over 220 countries used the GSM in 2018. 3G, 4G, and 5G have developed from
the GSM (2G). In 1982, under the auspices of CEPT, the Working Group GSM (Group Special
Mobile) established itself as the GSM standards body. When ETSI was founded in 1988, all
CEPT standardization activities were moved there. Technical Committee GSM was formed from
Working Group GSM. When ETSI charged the committee with UMTS in 1991, it changed its
name to Technical Committee SMG (Special Mobile Group) (3G).
In 1991, Sony and Asahi Kasei successfully marketed the lithium-ion battery, an essential power
source for contemporary cell phones. NTT DoCoMo introduced the third generation (3G) using
the WCDMA standard in Japan in 2001. Following this, the high-speed packet access (HSPA)
series of improvements, often known as 3.5G, 3G+ or turbo 3G, enabled UMTS networks to
support higher data transfer rates and capacities.
By 2009, it had become clear that, at some point, 3G networks would be overwhelmed by the
growth of bandwidth-intensive applications, such as streaming media. As a result, the market
started to focus on fourth-generation technologies that are data-optimized and promise speed
increases of up to ten times over current 3G technology. The WiMAX standard, made available
in North America by Sprint, and the LTE standard, originally made available in Scandinavia by
TeliaSonera, were the first two commercially viable technologies dubbed as 4G.
Telecommunications corporations or standardization organizations like 3GPP, WiMAX Forum,
or ITU-R have not yet made any specifications or official documents available to the public that
use the word "5G”. Standardization organizations are presently working on new standards that
go beyond 4G; however they are still considered to be part of the 4G period and not for a new
generation of mobile devices.
2.3
Types of Cell Phones
Smartphone
Smartphones have several distinguishing features. The International Telecommunication Union
measures those with an Internet connection, which it calls Active Mobile-Broadband
subscriptions (which includes tablets, etc.). Smartphone usage has now surpassed that of prior
mobile technologies in the industrialized countries. However, they make up around 50% of
mobile telecommunications in the underdeveloped world.
2.4
Feature phone
The phrase "feature phone" is often used as a retronym to characterize mobile phones that have
fewer features than a modern smartphone. In addition to rudimentary multimedia and Internet
capabilities, feature phones often include voice calling and text messaging features as well as
other services provided by the user's wireless service provider. A feature phone is more advanced
than a basic mobile phone, which can only make voice calls and send text messages. The
software and user interface of feature phones and entry-level mobile phones are frequently
proprietary and custom-made. Smartphones, on the other hand, typically run a mobile operating
system that frequently has features in common with other devices.
2.5
Infrastructure
Wi-Fi and cellular networks
To prevent interference, cellular networks only reuse radio frequencies (in this case, frequencies
f1–f4) in non-adjacent cells.
Cell towers, which are positioned to provide coverage across a telephone service area that is
broken up into "cells," are where mobile phones communicate. Each cell, which normally
consists of three towers positioned at various places, uses a unique set of frequencies from its
adjacent cells. Typically, wired connections connect the cell towers to the phone network, the
internet, and each other. Each cell will have a maximum number of cell phones it can support at
once due to bandwidth restrictions. As a result, the size of the cells is determined by the
anticipated usage density; in cities, they may be substantially smaller. In that case, much lower
transmitter powers are used to avoid broadcasting beyond the cell.
To handle the high traffic, multiple towers can be set up in the same area (using different
frequencies). This can be done permanently or temporarily such as at special events like the
Super Bowl, Taste of Chicago, State Fair, NYC New Year's Eve, the hurricane hit cities, etc.
where cell phone companies will bring a truck with equipment to host the abnormally high traffic
with a portable cell.
The number of concurrent wireless phone calls can be significantly increased using cellular.
Even though, for instance, a phone company is licensed to utilize 1,000 frequencies, each cell
must use distinctive frequencies, and each call must use one of them to communicate. The same
frequency can be utilized multiple times because cells only barely overlap. For instance, cell
number one utilizes frequency 1–500, cell number 501–1,000, and cell number 501–1,000 can
reuse frequency 1–500. Since cells one and three do not overlap or "touch," they can both use the
same frequencies.
The implementation of digital networks by phone companies further expanded capacity. With
digital, many calls can run simultaneously on one frequency.
A phone will "hand off," or automatically disconnect and reconnect to the tower of another cell
that provides the best reception, as it travels about.
Additionally, cellphones frequently employ short-range Wi-Fi infrastructure to dump data from
cell networks onto local area networks.
CHAPTER THREE
3.0
MATERIALS USED IN THE DEVELOPMENT
The Hardware
The common components found in all mobile phones

A central processing unit (CPU), is the processor of phones. The CPU is a
microprocessor fabricated on a metal–oxide–semiconductor (MOS) integrated circuit (IC)
chip.

A battery provides the power source for the phone's functions. A modern handset typically
uses a lithium-ion battery (LIB), whereas older handsets used nickel–metal hydride (Ni–
MH) batteries.

An input mechanism to allow the user to interact with the phone. These are a keypad for
feature phones and touch screens for most smartphones (typically with capacitive sensing).

A display that echoes the user's typing, and displays text messages, contacts, and more. The
display is typically either a liquid-crystal display (LCD) or organic light-emitting
diode (OLED) display.

Speakers for sound.

Subscriber identity module (SIM) cards and removable user identity module (R-UIM)
cards.

A hardware notification LED on some phones
Low-end mobile phones are often referred to as feature phones and offer basic telephony.
Handsets with more advanced computing ability through the use of native software applications
are known as smartphones.
3.1
Methods
An integrated circuit
Central processing units (CPUs) in mobile devices resemble those in computers but are designed
to work in low-power settings.
Performance of mobile CPUs is largely influenced by the memory hierarchy in addition to the
clock rate, which is often expressed in hertz multiples. Due to these issues, ratings obtained from
numerous standardized tests that reflect the actual effectiveness in commonly used applications
are frequently more acceptable indicators of the performance of mobile phone CPUs.
3.2
Display
The screen is one of a phone's primary features. The screen occupies most or nearly all of the
space on a device's front surface, depending on the type and design of the device. Although 16:9
is a standard aspect ratio for smartphone screens, taller aspect ratios started to appear more
frequently in 2017.
Diagonal inches or millimeters are common units for measuring screen sizes, and feature phones
often have screens that are less than 90 millimeters in size (3.5 in). Phablets are terms used to
describe phones with screens greater than 130 millimeters (5.2 in). When using a smartphone
with a screen larger than 115 millimeters (4.5 in), it can be challenging because most thumbs
can't reach the entire screen surface; It can be necessary to move them around in the hand, hold
them with one hand while manipulating them with the other, or use both hands to hold them in
place. While the transition to higher aspect ratios has produced phones with larger screen sizes
while keeping the ergonomics associated with smaller 16:9 displays, some contemporary
smartphones with enormous screen sizes and "edge-to-edge" designs have compact constructions
that improve their ergonomics. The most prevalent type of display is liquid crystal, but there are
also IPS, LED, OLED, and AMOLED models. Pressure-sensitive digitizers, such those made by
Wacom, Samsung, and Apple's "3D Touch" system, are built into some displays.
3.3
Sound
Smartphones and feature phones hardly differ in terms of sound. Newer smartphones frequently
come with certain audio-quality boosting technologies, such as Voice over LTE and HD Voice.
Due to the way the phone is built, the caliber of the cellular network, and the compression
techniques used during long-distance conversations, sound quality can still be an issue. Using a
VoIP app over WiFi might enhance audio quality. Small speakers are built into smartphones so
that a user can utilize the speaker phone feature and speak on the phone without having to hold it
up to their ear. You can watch videos with audio and listen to digital audio files of music or
conversation on the tiny speakers without having to hold the phone up to your ear.
3.4
Battery
The maximum battery life for a phone is two to three years. A Lithium-Ion (Li-Ion) battery is
used in many wireless devices. Depending on how the battery is cared for and how it is charged,
the battery can be recharged 500–2500 times. These rechargeable batteries inevitably experience
chemical aging, which is why after using them for a year or two, their performance starts to
suffer. By frequently draining the battery, avoiding overcharging it, and keeping it out of the
heat, the battery life can be increased.
3.5
SIM card
Typical mini-SIM card for mobile phones
To operate, mobile phones need a tiny microchip known as a Subscriber Identity Module, or SIM
card. The SIM card is often positioned behind the battery on the back of the device and is
roughly the size of a little postage stamp. The service-subscriber key (IMSI) is safely stored on
the SIM, and the Ki is used to identify and verify the mobile phone's owner. If a SIM lock is not
present, customers can switch phones by simply removing the SIM card from one mobile phone
and placing it into another mobile phone or internet telephony device. Giesecke & Devrient, a
Munich-based manufacturer of smart cards, created the first SIM card in 1991 for the Finnish
wireless network operator Radiolinja.
With a separate device identification for each SIM card, a hybrid mobile phone can
accommodate up to four SIM cards. To access both GSM and CDMA networks, SIM and RUIM cards may be combined. Such phones gained popularity in emerging nations starting in
2010[37], and this was ascribed to the need for the most affordable calling rates.
The operating system may prevent continued operation until a reboot if it detects the removal of
a SIM card.
Software Basic software platforms are available in feature phones. Modern software systems can
be found in smartphones. Since 2011, Android OS has dominated the market for smartphone
operating systems.
3.6
Mobile app
A computer program called a mobile app is created specifically to run on a mobile device, such a
smartphone. Software application is shortened to "app" in this sentence.
3.7
Messaging
SMS and MMS
A text message (SMS)
A common data application on mobile phones is Short Message Service (SMS) text messaging.
The first SMS message was sent from a computer to a mobile phone in 1992 in the UK while the
first person-to-person SMS from phone to phone was sent in Finland in 1993. The first mobile
news service, delivered via SMS, was launched in Finland in 2000, and subsequently many
organizations provided "on-demand" and "instant" news services by SMS. Multimedia
Messaging Service (MMS) was introduced in March 2002.
3.8
Application stores
Manufacturer-hosted online distribution for third-party apps (software and computer programs)
targeted at a single platform gained popularity with the launch of Apple's App Store for the
iPhone and iPod Touch in July 2008. There are a plethora of apps available, including gaming,
music, and business tools. Before before, the distribution of smartphone applications was reliant
on third-party providers of programs for various platforms, such as GetJar, Handango,
Handmark, and PocketGear. Following the success of the App Store, several smartphone makers
opened their own app shops, including RIM's BlackBerry App World, Google's Android Market
(later rebranded to the Google Play Store), and Aptoide, Cafe Bazaar, F-Droid, GetJar, and
Opera Mobile Store, which cater to Android users. 93% of mobile developers prioritized
smartphones for mobile in February 2014..
3.9
Uses of Mobile Phones
Mobile phones are used for a variety of purposes, such as keeping in touch with family members,
conducting business, and having access to a telephone in the event of an emergency. Some
people carry more than one mobile phone for different purposes, such as for business and
personal use. Multiple SIM cards may be used to take advantage of the benefits of different
calling plans. For example, a particular plan might provide for cheaper local calls, long-distance
calls, international calls, or roaming.
The mobile phone has been used in a variety of diverse contexts in society. For example:

A study by Motorola found that one in ten mobile phone subscribers has a second phone that
is often kept secret from other family members. These phones may be used to engage in such
activities as extramarital affairs or clandestine business dealings. Some organizations assist
victims of domestic violence by providing mobile phones for use in emergencies. These are
often refurbished phones. The advent of widespread text messaging has resulted in the cell
phone novel, the first literary genre to emerge from the cellular age, via text messaging to a
website that collects the novels as a whole.

Mobile telephony also facilitates activism and citizen journalism.

The United Nations reported that mobile phones have spread faster than any other form of
technology and can improve the livelihood of the poorest people in developing countries, by
providing access to information in places where landlines or the Internet are not available,
especially in the least developed countries. The use of mobile phones also spawns a wealth
of micro-enterprises, by providing such work as selling airtime on the streets and repairing or
refurbishing handsets. In Mali and other African countries, people used to travel from village
to village to let friends and relatives know about weddings, births, and other events. This can
now be avoided in areas with mobile phone coverage, which is usually more extensive than
areas with just land-line penetration.

The TV industry has recently started using mobile phones to drive live TV viewing through
mobile apps, advertising, social TV, and mobile TV. It is estimated that 86% of Americans use
their mobile phone while watching TV.

The sharing of mobile phones is widespread in several regions of the world. In metropolitan
India, it is common for families and groups of friends to share one or more mobile phones
among themselves. In addition to the apparent economic advantages, conventional gender
roles and family traditions frequently come into play. A hamlet frequently only has access to
one cell phone, which is available to all residents for calls that are necessary and may be
owned by a teacher or missionary.
3.10
Mobile banking and payment
In several nations, mobile phones are used to offer mobile banking services, some of which may
let users send secure SMS text messages to transfer money. Customers of the mobile phone
provider Safaricom in Kenya can hold cash balances that are recorded on their SIM cards thanks
to the M-PESA mobile banking service. At Safaricom retail locations spread across the nation,
customers can deposit or withdraw cash from their M-PESA accounts. Cash can also be
electronically transferred from one person to another and used to pay invoices to businesses.
South Africa and the Philippines have also shown success with branchless banking. The
International Finance Corporation and Bank Mandiri, an Indonesian bank, began a pilot initiative
in Bali in 2011. Zidisha is yet another mobile banking application, a US-based nonprofit microlending platform that allows residents of developing countries to raise small business loans from
Web users worldwide. Zidisha uses mobile banking for loan disbursements and repayments,
transferring funds from lenders in the United States to borrowers in rural Africa who have
mobile phones and can use the Internet. Mobile payments were first trialed in Finland in 1998
when two Coca-Cola vending machines in Espoo were enabled to work with SMS payments.
Eventually, the idea spread, and in 1999, the Philippines launched the country's first commercial
mobile payments systems with mobile operators Globe and Smart.
Some mobile phones can make mobile payments via direct mobile billing schemes, or through
contactless payments, if the phone and the point of sale support near-field communication
(NFC). Enabling contactless payments through NFC-equipped mobile phones requires the
cooperation of manufacturers, network operators, and retail merchants.
Manufacturers, network providers, and retail businesses must all work together to make
contactless payments possible on mobile devices with NFC capabilities.
3.10.1 Mobile tracking
Location data is frequently gathered via mobile phones. Using a method called multilateration to
determine the differences in time for a signal to travel from the mobile phone to each of several
cell towers close to the phone owner, it is simple to determine the geographic location of a
mobile phone while it is turned on (regardless of whether it is in use or not).
The location of a mobile phone user can be traced by their service provider, as well as, if wanted,
by their governments and law authorities. The SIM card and the phone can both be followed.
China has suggested deploying this technology to monitor residents of Beijing's commuter
patterns. Law enforcement and intelligence services in the US and the UK use mobile devices for
surveillance purposes. They have access to technology that makes it possible for them to
remotely activate mobile phones' microphones in order to listen in on nearby conversations. With
merely the phone number, hackers may read messages, listen to calls, even track the location of a
phone.
CHATER FOUR
4.0
RESULT AND DISCUSION
Generations in the development of mobile telephone networks mean improvement in services:
new service providing logic and new telecommunication network architecture.
The first-generation cellular system was an analog Frequency Modulation (FM) system which
was entirely for voice transfer and was introduced in 1985 but had capacity limitations of Time
Division Multiple Access (TDMA), incompatibility problems, coverage limited to a geographical
entity, low speech quality, no open interfaces except the radio interface and lack of security in
speech transmission. The second-generation mobile cellular systems use digital radio
transmission. The boundary between the first- and the second-generation systems is the
analog/digital split. The second-generation networks have a much higher capacity than the firstgeneration systems. One frequency channel is divided simultaneously among several users either
by Code Division Multiple Access (CDMA) or time (TDMA) division. They are structured atop
existing first-generation analog technology and are premised on compatibility and parallel
operation with analog networks.
Generation 2.5 is a designation that broadly includes all advanced upgrades for the secondgeneration networks. The third-generation systems can be used not only for person-to-person
Communication but also for person-to-machine communication based on Wideband Code
Division Multiple Access (W-CDMA) radio technology. The 3G systems are targeted to offer a
wide variety of services such as telephony, teleconference, voice mail, message broadcast
navigation, etc, and will pave the way for 4G, which is likely to be the first truly converged
network that will incorporate new services more advanced than what the 3G offers.
CHAPTER FIVE
5.1
CONCLUSION
Early cell phones were just for talking. Gradually, features like voicemail were added, but the
main purpose was to talk. Eventually, cell phone manufacturers began to realize that they could
integrate other technologies into their phones and expand their features. The earliest smartphones
let users access email, and use the phone as a fax machine, pager, and address book.
In recent years, the purpose of the cell phone has shifted from a verbal communication tool to a
multimedia tool, often adopting the name "mobile device" rather than being called a phone at all.
We now use our cell phones more for surfing the web, checking email, snapping photos, and
updating our social media status than actually placing calls.
“Rapidly expanding software titles, better screen resolution, and constantly improved interface
make cell phones easier to navigate, and more fun to use. Add to that an expanding capacity that
can hold as much memory as a computer would just a few years ago, and you can see why it’s an
exploding market,” Grullon says.
The cell phones of today are also replacing our other gadgets, such as cameras and video
cameras. When cameras were first introduced on phones, the images were low quality, and the
feature was considered to just be an extra.
"Now, we're seeing a very fast shift to where consumers don't even bother carrying their pointand-shoot cameras anymore and just use their cell phones," says Jamie Lendino, a tech journalist
and senior mobile analyst for PCMag.com.
Modern-day smartphones the Apple iPhone in particular changed everything that consumers
expect from their phones. The app market has transformed the phone into a virtual toolbox with a
solution for almost every need.
5.2
RECOMMENDATION
To meet up with the technological demands of the country on cell phones, the following
recommendation should be considered:
1. Integration of immobilizer with more security system on every phone.
2. Integrating every phone with more attractive features
Reference
1. ^ Jump up to:a b Teixeira, Tania (23 April 2010). "Meet the man who invented the
mobile phone". BBC News. Retrieved 2 July 2021.
2. ^ "Timeline from 1G to 5G: A Brief History on Cell Phones". CENGN. 21 September 2020.
Retrieved18 February 2022.
3. ^ "Mobile penetration". 9 July 2010. Almost 40 percent of the world's population, 2.7
billion people, are online. The developing world is home to about 826 million female
internet users and 980 million male internet users. The developed world is home to about
475 million female Internet users and 483 million male Internet users.
4. ^ "Gartner Says Worldwide Smartphone Sales Grew 3.9 Percent in the First Quarter of
2016". Gartner. Archived from the original on 22 May 2016. Retrieved 21 May 2016.
5. ^ "Nokia
Captured
9%
Feature
Phone
Marketshare
Worldwide
in
2016".
Strategyanalytics.com. 24 February 2017. Retrieved 7 September 2018.
6. ^ Harris, Arlene; Cooper, Martin (2019). "Mobile phones: Impacts, challenges, and
predictions". Human
Behavior
and
Emerging
Technologies. 1:
15–
17.doi:10.1002/hbe2.112. S2CID 187189041.
7. ^ "BBC News | BUSINESS | Mobile phone sales surge".
8. ^ Gupta,
Gireesh
(2011). "Ubiquitous
K.
indispensable". ACM
mobile
phones
Inroads. 2 (2):
are
becoming
32–
33.doi:10.1145/1963533.1963545. S2CID 2942617.
9. ^ "Mobile
phones
are
becoming
ubiquitous". International
Telecommunication
Union (ITU). 17 February 2022.
10. ^ John F. Mitchell Biography
11. ^ Who invented the cell phone?
12. ^ "Swedish National Museum of Science and Technology". Tekniskamuseet.se. Archived
from the original on 22 October 2008. Retrieved 29 July 2009.
13. ^ Baliga,
B.
Jayant (2005). Silicon
RF
Power
MOSFETS.World
Scientific. ISBN 9789812561213.
14. ^ Asif, Saad (2018). 5G Mobile Communications: Concepts and Technologies. CRC Press.
pp. 128–134.ISBN 9780429881343.