Post on 14-Aug-2020
transcript
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ECE4900/ECE6720 Digital Communications Suketu Naik
ECE4900/ECE6720: Digital Communications
Lecture 1
Introduction to
Communication
Systems
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ECE4900/ECE6720 Digital Communications Suketu Naik
What is a Communication System?
Smart Phone
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ECE4900/ECE6720 Digital Communications Suketu Naik
What is a Communication System?
Transceivers in Smart Cars
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ECE4900/ECE6720 Digital Communications Suketu Naik
What is a Communication System?
Navigation and Communication Radios in Boats
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ECE4900/ECE6720 Digital Communications Suketu Naik
What is a Communication System?
Portable Transceivers
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ECE4900/ECE6720 Digital Communications Suketu Naik
What is a Communication System?
Underwater Acoustic Radio
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ECE4900/ECE6720 Digital Communications Suketu Naik
What is a Communication System?
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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ECE4900/ECE6720 Digital Communications Suketu Naik
Block Diagrams of Communication System
Generic Communication SystemQualcomm MDM9635M LTE Modem in iphone6
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ECE4900/ECE6720 Digital Communications Suketu Naik
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
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ECE4900/ECE6720 Digital Communications Suketu Naik
Basics of Wireless Communications
Frequency Bands
Cellular
Frequencies
3G, 4G, LTE
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ECE4900/ECE6720 Digital Communications Suketu Naik
Basics of Wireless Communications
ISM (Industrial, Scientific and Medical) Bands
IEEE 802.11 standards
Used for short-range wireless (home, office etc)
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ECE4900/ECE6720 Digital Communications Suketu Naik
Block Diagrams of Communication System
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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ECE4900/ECE6720 Digital Communications Suketu Naik
Block Diagrams of Communication System
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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ECE4900/ECE6720 Digital Communications Suketu Naik
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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ECE4900/ECE6720 Digital Communications Suketu Naik
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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ECE4900/ECE6720 Digital Communications Suketu Naik
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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ECE4900/ECE6720 Digital Communications Suketu Naik
WTR3925 and MDM9635 Block Diagrams
Qualcomm WTR3925
Qualcomm MDM9635M
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ECE4900/ECE6720 Digital Communications Suketu Naik
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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ECE4900/ECE6720 Digital Communications Suketu Naik
Final Project: Example Wireless Standards
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ECE4900/ECE6720 Digital Communications Suketu Naik
Final Project: Modulation Schemes
1) http://mcsindex.com/
2) Explanation
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ECE4900/ECE6720 Digital Communications Suketu Naik
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”