Lecture 1 Introduction to Communication Systems · Introduction to Communication Systems. 2 ... 2) The alteration of carrier signal is called modulation 3) The modulated carrier signal

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ECE4900/ECE6720 Digital Communications Suketu Naik

ECE4900/ECE6720: Digital Communications

Lecture 1

Introduction to

Communication

Systems

2


What is a Communication System?

Smart Phone

3



Transceivers in Smart Cars

4



Navigation and Communication Radios in Boats

5



Portable Transceivers

6



Underwater Acoustic Radio

7



Beehive of Satellites enable Communications!

Total number of operational satellites in orbit=1400

(Total number of junk satellites in orbit=2500)

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Block Diagrams of Communication System

Generic Communication SystemQualcomm MDM9635M LTE Modem in iphone6

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Basics of Wireless Communications

Transmitter transmits information via carrier signalQ: Why do we need carrier signal?

A: 1) Carrier signal “carries” information by alteration of its amplitude,

frequency and/or phase

2) The alteration of carrier signal is called modulation

3) The modulated carrier signal can be transmitted with smaller antennas

at lower power to reach long distances

Information

(baseband signal at

lower frequency)

Carrier signal

at higher

frequency

Up-converted

Baseband

Signal

10



Frequency Bands

Cellular

Frequencies

3G, 4G, LTE

11



ISM (Industrial, Scientific and Medical) Bands

IEEE 802.11 standards

Used for short-range wireless (home, office etc)

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Digital Communication System

Informatio

n (sound,

video, text,

data, …)

Transducer &

A/D ConverterModulator

Source

Encoder

Channel

Encoder

Tx RF

System

Output

Signal

D/A Converter

and/or output

transducer

DemodulatorSource

Decoder

Channel

Decoder

Rx RF

System

Channel

= Focus of this class

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Software Defined Radio (SDR)

In SDR, the transmitter and receiver operations can be changed by

software alone without making any changes to the hardware

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Software Defined Ratio (SDR)

Examples

Microtelecom PERSEUSGreat Scott Gadgets

HACKRF

Nuand BLADERF

Limemicro LIMESDR Ettus Research

USRP

Airspy

AIRSPY MINI

SDRs can implement any modulation type between 100 kHz to 6 GHz

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Software Defined Ratio (SDR)

5G Wireless Prototyping

(mobile network at 10

Gb/s, NI research)

Amateur Radio

ReceiverAIS Tracking

(locate ships)

Joint Tactical Radio

System (JTRS)

Satellite Receiver Public Safety and

Emergency Response

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Inside the Smart Phone: The Transceiver

Qualcomm MDM9635M/WTR1605/WTR3925 RF Transceivers

(used in phone and tablets for 2G, 3G, 4G/LTE)

Qualcomm MDM9635M

Qualcomm WTR3925

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WTR3925 and MDM9635 Block Diagrams

Qualcomm WTR3925

Qualcomm MDM9635M

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Final Project

Undergraduate Students will simulate receiver for a given

Standard (3G, 4G/LTE, Wifi, Wimax, etc): demonstrate

data transfer

Graduate Students will simulate transceiver for a given Standard

(3G, 4G/LTE, Wifi, Wimax, etc): demonstrate data transfer

Informatio

n (sound,

video, text,

data, …)

Transducer &

A/D ConverterModulator

Source

Encoder

Channel

Encoder

Tx RF

System

Output

Signal

D/A Converter

and/or output

transducer

DemodulatorSource

Decoder

Channel

Decoder

Rx RF

System

Channel

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Final Project: Example Wireless Standards

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Final Project: Modulation Schemes

1) http://mcsindex.com/

2) Explanation

http://mcsindex.com/

http://www.digitalairwireless.com/wireless-blog/recent/demystifying-modulation-and-coding-scheme-index-values.html

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Final Project: Deliverables

Bit Error Rate (BER) Plots

Successful Decoding of Data or Image

“I like Sunspots” Simulink Model for

802.11a, g, GSM, or

LTE etc

“I like Sunspots”

Documents

Lecture 1 Introduction to Communication Systems · Introduction to Communication Systems. 2 ... 2) The alteration of carrier signal is called modulation 3) The modulated carrier signal