1. EE 320
CH_1
Basic Elements of a Communication
System
Class 1

2. EE 320
Outline
 Instructor information
 Motivation to study communication systems
 Course descriptions and textbooks
 What you will study from this course
 Objectives
 Coverage and schedule
 Homework, projects, and exams
 Other policies
 Reasons to be my students
 Background and Preview

3. EE 320
Motivations
 Recent Development
– Satellite Communications
– Telecommunication: Internet boom at the end of last decade
– Wireless Communication: next boom? iPhone
 Job Market
– Probably one of most easy and high paid majors recently
– Intel changes to wireless,
– Qualcom, Broadcom, TI, Marvell, Cypress
 Research Potential
– One to one communication has less room to go, but
multiuser communication is still an open issue.
– Wimax, 3G, next generation WLAN

4. EE 320
Course Descriptions
 What is the communication system?
 What are the major types?
 Analog or Digital
 Satellite, Fiber, Wireless…
 What are the theorems?
 What are the major components?
 How is the information transmitted?
 What are the current industrial standards?
 What are the state-of-art research?
 Can I find a job by studying this course?
 Can I find research topics?

5. EE 320
Textbook and Software
 Require textbook:
Simon Haykin, Communication Systems, 4th edition, John
Wiley and Sons, Inc.
 Require Software: MATLAB
http://www.mathworks.com/ or type helpwin in Matlab environment
 Recommended readings
 Digital communications: J. Proakis, Digital Communications
 Random process: G.R. Grimmett and D.R. Stirzaker, Probability and
Random Processes
 Estimation and detection: H.V. Poor, An introduction to Signal
Detection and Estimation
 Information theory: T. M. Cover and J. A. Thomas, Elements of
Information Theory
 Error correct coding: P.Sweeney, Error Control Coding

6. EE 320
Schedule
•8/22: background and preview
•8/28 ~9/2: Chapter 1
•9/4-9/18: Chapter 2
•9/23-10/2: Chapter 3
•10/7: Midterm 1 (Chapter 0-Chapter 3)
•10/9-10/21: Chapter 4
•10/23-10/30: Chapter 5
•11/4-11/9: Chapter 6
•11/13-11/25: Chapter 7
•11/27: Midterm 2 (Chapter 4-Chapter 6)
•12/2-12/4: Chapter 8
•12/9-12/11: Chapter 10
•Final Exam (Chapter 7, 8, 10)

7. EE 320
Homework, Project, and Exam
 Homework
 2 questions per week for undergraduate, 3~4 for graduate
 Projects: simple MATLAB programs
 AM/FM Modulation
 BPSK Modulation (undergraduate), BPSK/MQAM (graduate)
 USRP2/GnuRadio if the hardware will be ready.
 Exams
 Three independent exams
 Votes for the percentages for homework, projects, and exams
 Participations
 Attendance and Feedback
 Quiz if the attendance is low

8. EE 320
Teaching Styles
 Slides plus black board
 Slides can convey more information in an organized way
 Blackboard is better for equations and prevents you from
not coming.
 Course Website
 Print handouts with 3 slides per page before you come
 Homework assignment and solutions
 Project descriptions and preliminary codes
 Feedback
 Too fast, too slow
 Presentation, Writing, English, …

9. EE 320
Communication System
A B
Engineering System
Genetic System
Social System
History and fact of communication

10. Communication System Components
Source
Coder
Channel
Coder
Modulation
+
Source
decoder
Channel
decoder
demodulation
Distortion and noise
transmitter
channel
receiver
Source
input
Reconstructed
Signal
output
D/A
A/D

11. Communication Process
 Message Signal
 Symbol
 Encoding
 Transmission
 Decoding
 Re-creation
 Broadcast
 Point to Point

12. Telecommunication
 Telegraph
 Fixed line telephone
 Cable
 Wired networks
 Internet
 Fiber communications
 Communication bus inside computers to communicate
between CPU and memory

13. Wireless Communications
 Satellite
 TV
 Cordless phone
 Cellular phone
 Wireless LAN, WIFI
 Wireless MAN, WIMAX
 Bluetooth
 Ultra Wide Band
 Wireless Laser
 Microwave
 GPS
 Ad hoc/Sensor Networks

14. Analog or Digital
 Common Misunderstanding: Any transmitted signals are
ANALOG. NO DIGITAL SIGNAL CAN BE TRANSMITTED
 Analog Message: continuous in amplitude and over time
– AM, FM for voice sound
– Traditional TV for analog video
– First generation cellular phone (analog mode)
– Record player
 Digital message: 0 or 1, or discrete value
– VCD, DVD
– 2G/3G cellular phone
– Data on your disk
– Your grade
 Digital age: why digital communication will prevail

15. Source Coder
 Examples
– Digital camera: encoder;
TV/computer: decoder
– Camcorder
– Phone
– Read the book
 Theorem
– How much information is
measured by Entropy
– More randomness, high
entropy and more information

16. Channel, Bandwidth, Spectrum
 Bandwidth: the number of bits per second is proportional to B
http://www.ntia.doc.gov/osmhome/allochrt.pdf

17. Power, Channel, Noise
 Transmit power
– Constrained by device, battery, health issue, etc.
 Channel responses to different frequency and different time
– Satellite: almost flat over frequency, change slightly over time
– Cable or line: response very different over frequency, change
slightly over time.
– Fiber: perfect
– Wireless: worst. Multipath reflection causes fluctuation in
frequency response. Doppler shift causes fluctuation over time
 Noise and interference
– AWGN: Additive White Gaussian noise
– Interferences: power line, microwave, other users (CDMA phone)

18. Shannon Capacity
 Shannon Theory
– It establishes that given a noisy channel with information capacity C and
information transmitted at a rate R, then if R<C, there exists a coding
technique which allows the probability of error at the receiver to be made
arbitrarily small. This means that theoretically, it is possible to transmit
information without error up to a limit, C.
– The converse is also important. If R>C, the probability of error at the
receiver increases without bound as the rate is increased. So no useful
information can be transmitted beyond the channel capacity. The theorem
does not address the rare situation in which rate and capacity are equal.
 Shannon Capacity
s
bit
SNR
B
C /
)
1
(
log2 


19. Modulation
 Process of varying a carrier signal
in order to use that signal to
convey information
– Carrier signal can transmit far
away, but information cannot
– Modem: amplitude, phase, and
frequency
– Analog: AM, amplitude, FM,
frequency, Vestigial sideband
modulation, TV
– Digital: mapping digital
information to different
constellation: Frequency-shift
key (FSK)

20. Example
 Figure 10
 Modulation over carrier fc
s(t)=Accos(2fct) for symbol 1; -Accos(2fct) for symbol 0
 Transmission from channel
x(t)=s(t)+w(t)
 Correlator
 Decoding
– If the correlator output yT is greater than 0, the receiver output
symbol 1; otherwise it outputs symbol 0.







  0
,
5
.
0
1
,
5
.
0
)
2
cos(
)
(
0
symbol
for
w
A
symbol
for
w
A
dt
t
f
t
x
y
T
c
T
c
T
c
T 

21. Channel Coding
 Purpose
– Deliberately add redundancy to the transmitted information, so
that if the error occurs, the receiver can either detect or correct it.
 Source-channel separation theorem
– If the delay is not an issue, the source coder and channel coder can
be designed separately, i.e. the source coder tries to pack the
information as hard as possible and the channel coder tries to
protect the packet information.
 Popular coder
– Linear block code
– Cyclic codes (CRC)
– Convolutional code (Viterbi, Qualcom)
– LDPC codes, Turbo code, 0.1 dB to Channel Capacity

22. Quality of a Link (service, QoS)
 Mean Square Error
 Signal to noise ratio (SNR)
– Bit error rate
– Frame error rate
– Packet drop rate
– Peak SNR (PSNR)
– SINR/SNIR: signal to noise plus interference ratio
 Human factor




N
i
i
i X
X
N
MSE
1
2
|
ˆ
|
1
2
2


G
P
P tx
rec




23. Communication Networks
 Connection of 2 or more distinct (possibly dissimilar) networks.
 Requires some kind of network device to facilitate the
connection.
 Internet
Net A Net B

24. Broadband Communication

25. OSI Model
Open Systems Interconnections; Course offered next semester

26. TCP/IP Architecture
• TCP/IP is the de facto
global data
communications standard.
• It has a lean 3-layer
protocol stack that can be
mapped to five of the
seven in the OSI model.
• TCP/IP can be used with
any type of network, even
different types of networks
within a single session.

27. Summary
 Course Descriptions
 Communication System Structure
– Basic Block Diagram
– Typical Communication systems
– Analog or Digital
– Entropy to Measure the Quantity of Information
– Channels
– Shannon Capacity
– Spectrum Allocation
– Modulation
– Communication Networks