4g Wireless Technology (2)

7/29/2019 4g Wireless Technology (2)

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4G Wireless

Technology

Presented

By RAJ MOYAL


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4G Definition

4G is a collection of technologies at

creating fully packet-switched networks

optimized for data.

4G Networks are projected to provide

speed of 100Mbps while moving and1Gbps while stationary.


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1G Technology

1G refers to the first-generation ofwireless telephone technology was

developed in 1970s.

1G had two major improvements:

the invention of the microprocessor

the digital transform of the control linkbetween the phone and the cell site.


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2G Technology

Around 1980s

Better quality & capacity - More people

could use there phones at the same

time

Digital Signalsconsist of 0s & 1s


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Previous Technology - 2G

Digitalconsist of 0s and 1s

Digital signal:

1.Low level, 2.High level, 3.Rising edge

and 4.Falling edge


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Allows for lower powered radio signals that

require less battery.

PowerCODEC introduction -program that

encodes and decodes digital data stream or

signal.

Translates data from digital to analog and

vice versa.


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Function of codec


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Disadvantages in Previous

Technology - 2G

Cell towers had a limited coverage

area

Decay curve Abrupt dropped calls

Analoggradual sound reduction

Spotty coverage


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3G Technology

Large capacity and broadband capabilities

Allows the transmission of 384kbps formobile systems and up to 2Mbps.

Increased spectrum efficiency5Mhz A greater number of users that can be

simultaneously supported by a radio frequencybandwidth.

High data rates at lower incremental cost than2GGlobal roaming.


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CDMACode Division Multiple Access

Form of multiplexing

Does not divide up the channel by time or

frequency.

Encodes data with a special code

associated with each channel.


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Types of Multiplexing

FDMA Frequency Division Multiple

Access

Each phone call is allocated onefrequency for the entire duration of the

call.


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TDMA - Time Division Multiple Access

Each phone call is allocated a spot in the

frequency for a small amount of time, and"takes turns" being transmitted.


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CDMA - Code Division Multiple Access

Each phone call is uniquely encoded and

transmitted across the entire spectrum, ina manner known as spread spectrum

transmission.


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Reasons for New Research

Even though 3G has successfully beenintroduced to mobile users, there are someissues that are debated by 3G providers andusers.

High input fees for the 3G service licenses.

Great differences in the licensing terms.

3G phones are expensive.


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Fourth Generation


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4G Technology

Fourth Generation Technology Faster and more reliable

100 Mb/s

Lower cost than previous generations

Technology used

Ad Hoc Networking Smart antenna

IPv6

VOIP

OFDM used instead of CDMA


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Ad Hoc Networks

Spontaneous selforganization of networksof devices.

Not necessarily connectedto internet.

4G will create hybridwireless networks usingAd Hoc networks.

Form of meshnetworkingVery reliable.


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Smart Antennas

Beam radio signals directly at a user to follow the

user as they move.

Allow the same radio frequency to be used for other

users without worry of interference. Cant keep up transmission speeds while device is

moving fast (i.e. in a car)

Only 32Mb/s at 62mph (vs 100Mb/s)

Seamless handoff between towers/access points.


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One transmit antenna, two receive antennas

Allows connection to two access points at once.


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Mobile IPv6

More addresses than current version of IP protocol

(Version 4) - each device can have own IP.

Keep IP address even if you change access point.

Presently translate IP with each change because notenough IP addresses to go around.

IP Core- everything can talk to each other if they speak

the same language (protocol).


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The IP address is based on IPv6.

IPv4: X . X . X . X (32 bits)

example: 216.37.129.9

IPv6: 4 IPv4 (128 bits)

example:

216.37.129.9 , 79.23.178.229 , 65.198.2.10 , 192.168.5.120

How 4G works (working principle)


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Mobile VoIP

Voice Over Internet Protocol

Allows only packets (IP) to be transferred, eliminatingcomplexity of 2 protocols over the same circuit.

All voice data will be wrapped up in a packet lower latency data transmission (fastertransmission).

Samples voice between 8,000 & 64,000 times per second

and creates stream of bits which is then compressed andput into a packet.


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OFDM

Orthogonal Frequency Division Multiplexing

Allows for transfer of more data than other forms of

multiplexing (time, frequency, code, etc).

Simplifies the design of the transmitter & receiver.

Allows for use of almost the entire frequency band

No gaps to prevent interference.

Currently used in WiMax (802.16) and Wi-Fi(802.11a/g).


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How OFDM Works

It uses binary phase shift keying (BPSK). The

phase of the sine wave changes to represent a

different bit.


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OFMD

The frequencies are spaced so that the signals donot interfere with each other (no cross talk).

Parallel Data Transmission - Allows for the sending

of multiple signals simultaneously from the sameantenna to one device.

Each transmission has a different stream of

bits.


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Disadvantages

Unfortunately, to use packet, all cellular hardware will need to

be upgraded or replaced.

Consumers will be required to purchase new phones, andproviders will need to install new equipment in towers.

Essentially, the communication system will need to be rebuilt

from the ground up, running offof data packets instead of

voice information.


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Thanking You

4g Wireless Technology (2)

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