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MOBILE NETWORKS Copyright 2012 Mocomi & Anibrain Digital Technologies Pvt. Ltd. All Rights Reserved. © General Knowledge for Kids mocomi.com/learn/general-knowledge/

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Page 1: Mobile Networks – Mocomi.com

MOBILE NETWORKS

Copyright 2012 Mocomi & Anibrain Digital Technologies Pvt. Ltd. All Rights Reserved. ©

General Knowledge for Kidsmocomi.com/learn/general-knowledge/

Page 2: Mobile Networks – Mocomi.com

A few years a�er Alexander Graham Bell invented the

telephone in 1876, a couple of scientists independently

began doing research on sending electromagnetic

signals, similar to the ones used in a telephone, through

the air.

�e discovery of radio waves transformed communica-

tion around the world because people could send and

receive messages without the use of a wire. It would

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Page 3: Mobile Networks – Mocomi.com

only be a matter of time before the radio and the telephone would be combined into the mobile phone.

A man named Jagdish Chandra Bose was a pioneer in

the ­eld of wireless communication. However he did

not believe in patenting his research because he be-

lieved that this scienti­c breakthrough should be avail-

able for all to take and

replicate. �is is why

Guglielmo Marconi is

o�en attributed with the

discovery of wireless technology. Before we learn about the

complex system of mobile telephone networks, we

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Page 4: Mobile Networks – Mocomi.com

should understand how the most basic two-way radio

works. A two-way radio or walkie-talkie has a transmit-

ter to send radio signals and an antenna to receive

them.

A transmitter is the part of a device that has the ability

to change the frequency and amplitude of a wave into

an electromagnetic signal.

In this case it is a sound

wave.

�e antenna of another

walkie-talkie picks up this signal and converts it back

into a sound wave which we can understand. However,

this system is limited because it only allows you to

transmit information over 1 channel and only one Copyright 2012 Mocomi & Anibrain Digital Technologies Pvt. Ltd. All Rights Reserved. ©

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Page 5: Mobile Networks – Mocomi.com

person can be talking at any given time since both talk-

ing and listening occur over the same channel.

Mobile phones are di�erent because they use 1 channel

to transmit and another one to receive. Before mobile

technology was developed the way it is today, there

were radio phones. �e radio-telephone system used

one radio tower that had 25 channels. �is antenna was

responsible for receiving signals from one radio-phone

and sending it to a desired destination.

walkie-talkie

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Page 6: Mobile Networks – Mocomi.com

But the phones themselves were huge because they had

to be powerful enough to transmit and receive signals

for up to 70 kms.

A cellphone network avoids this problem by breaking

up this area into many pieces known as cells. Each cell

has its own radio tower that has a range of about 26

square kms. �ink of each cell as a hexagon placed

beside another hexagon, on a larger hexagonal grid.

Mobile

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Page 7: Mobile Networks – Mocomi.com

Today, in 2012, we have phones and other hand-held

devices that allow you talk on the phone, upload photographs, download music and much more, but this

wasn't always the case. Let's see how this development

came about from the early days of wireless communica-

tion.

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Page 8: Mobile Networks – Mocomi.com

1G refers to the ­rst generation of mobile communica-

tion technology. �is was an analog system that was

­rst introduced in Japan by the Nippon Telegraph and

Telephone in 1979.

�e voice signal from the handset was was sent to a

tower at a high analog frequency.

1G

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Page 9: Mobile Networks – Mocomi.com

�e tower would pick up this signal and convert it to

digital before transmitting it to another tower in the

area. �e second tower would locate the desired re-

ceiver, convert the digital signal back to analog, which

the handset would convert into sound waves.

Japan was very successful

in implementing this

technology and within

­ve years it had become

the ­rst nationwide 1G

network.A single cell

tower in the 1G network had a very limited capacity

because each phone call used 4 channels at any given

time- 2 for listening at each telephone and 2 for talking.

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Page 10: Mobile Networks – Mocomi.com

�is was not a very e�cient system and was not secure

because it used radio frequencies that cannot be easily

encrypted for the purpose of a phonecall. An added

problem was that when a signal moved out of the range

of one tower to another, calls would not be transferred

properly and would get disconnected.

You might be wondering

what exactly an analog

signal is, so before we

make the switch to digi-

tal, let's ­nd out.

An analog signal is a

continuous signal that

�uctuates i.e. it is always

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Page 11: Mobile Networks – Mocomi.com

evolving and every point of the signal is signi­cant to

the information it is carrying.

�is means that every part of an analogue signal carries

important data that is di�erent to another point on the

same signal.

Digital data on the other hand is a bundle of informa-

tion that has to be unbundled before it can be interpreted.

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Page 12: Mobile Networks – Mocomi.com

�e big breakthrough with 2G was that it was an en-

tirely digital network. �e 1G network used an analog

signal to connect with cellphone towers which limited

the range and the number of users that could be on a

call at any given time.

�e second generation

(2G) mobile communica-

tion system can be divided

into 3 parts- FDMA,

CDMA and TDMA, which

are basically di�erent ways

in which cellphones could

access the channels of a tower.

FDMA (Frequency Division Multiple Access)FDMA

2G

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Page 13: Mobile Networks – Mocomi.com

was not the most e�cient of the three systems because

while it was able to handle digital data, it was simply a

more sophisticated way of transmitting analog signals.

It split a single channel into uniform pieces of band-

width and allowed multiple cellphones to access the

same channel through small

variations in frequency.

TDMA (Time Division Multiple

Access)One of the basic concepts

of mobile communication is to

allow multiple users to send and

receive information over 1 channel i.e. many people

could share the same bandwidth. Consider any 1 chan-

nel on a mobile tower which is able to send and receive

a ­xed amount of data per second. TDMA split this one

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Page 14: Mobile Networks – Mocomi.com

second into three and allowed three di�erent users to

share each second of space on a channel. Network

speeds had risen greatly a�er making the switch from

analog to digital signals, which allowed for towers to

relay messages at a fraction of a second.

CDMA (Code Division Multiple Access)Instead of

breaking up the channels into smaller parts, the CDMA

system broke the information into smaller packets of

information. Using a unique spreading code, these

packets were spread over multiple towers along with in-

formation on its destination. Once all the packets

reached the destination tower, it was reassembled into

its original form and sent to the receiver in one part.

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Page 15: Mobile Networks – Mocomi.com

�e third generation (3G) of mobile networking

systems o�ered a wider variety of services than what

came before and also increased the speeds at which in-

formation was relayed.

�e 3G network allowed people to download

information at 14.4 Mb per second and an upload speed

of 5.8 Mb per second. �is network opened the road to

accessing the internet on your mobile device and also

protecting the information you sent and received much

more e�ciently than the 2nd generation.

3G

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Page 16: Mobile Networks – Mocomi.com

�ere is a current generation of a communication

network called the fourth generation (4G) that is still

in its development phase, although some countries

have begun implementing this technology already.

Usually the quality of

speed diminishes when

the location of the phone

is constantly moving. �e

4G system increases the

e�ciency of the network

by improving the antenna in your mobile

device without compro-

mising on design. It

boasts of greater internet

4G

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Page 17: Mobile Networks – Mocomi.com

speeds on highly secure channels. �is new network

is allows people to use multimedia applications that

handle audio, video, and encrypted information with

very little loss of quality.

It took inventors around 100 years to combine the tel-

ephone and the radio into the mobile phone. However,

the advances in mobile phone networks have grown

leaps and bounds since the radio-phone was intro-

duced in the 1970's.

As wired telephones

slowly become a thing

of the past, mobile

phone are packed with

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Page 18: Mobile Networks – Mocomi.com

as technology experts continually reduce the size of the

device while increasing its power and e�ciency. Mobile

phone technology is moving at a furious pace towards

creating a more connected world. �ese networks allow

us to connect with family living in other countries, it

helps scientists track important information about our

planet over vast distances, and basically makes our

large planet seem a little smaller and connected. So take

a good look at that tiny mobile phone in your hand and

know that this little piece of technology is changing the

way the world communicates and interacts.

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Page 19: Mobile Networks – Mocomi.com

Project

Now that you know how wireless communication

works, go backwards and ­nd out how regular tel-

ephones (with wires) work. You can start by google the

words 'how a telephone works'.

Some phones, especially those made for the US market

cannot be used with sim-cards from outside the US.

Can you ­nd out why this is?

Using your amazing research skills, ­nd out about the

di�erent advances in radio that were put forth by

Nikolai Tesla and Guglielmo Marconi.

Image Source: www.wikipedia.orgAll images are public domain, sourced from the wikipedia commons

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