ECE 361: Digital Communications
Spring 2016
Lecturer:
Prof. Lav R. Varshney, varshney@illinois.edu
Office Hours: T 12:30-2:00pm, 314 CSL and by appointment
Teaching Assistant:
Yang Zhang, yzhan143@illinois.edu
Office Hours: 10:00-11:30am, 2169 Beckman Institute and by appointment
Lecture:
TR 9:30-10:50am, 4070 Electrical & Computer Engineering Building
Course Webpage:
http://courses.ece.uiuc.edu/ece361/
Course Goals
This course is aimed at introducing the fundamentals of digital communication to (junior/senior)
undergraduates. The background expected includes a prior course in signals and systems (usually ECE
210) and familiarity with statistical and probabilistic methods (usually ECE 313). The goals of the course
are to familiarize students with modeling, design, and performance analysis of digital communication
systems over two very common physical media: wireline and wireless channels. Students will also gain
an understanding of the engineering theory approach to designing, optimizing, and understanding the
fundamental limits of information systems. At the end of the course, students should be able to:
 Reason about and determine appropriate statistical models for random physical phenomena.
Specifically, this should be done for wireline and wireless channels of various kinds.
 Translate the statistical modeling of the physical media into design strategies at the transmitter
and the receiver. This should be done, specifically, for both the wireline and wireless channel
models arrived at earlier.
 Understand trade-offs among resources (bandwidth and power) and performance criteria (data
rate and reliability). This should be specifically done for the wireline and wireless channels. The
key difference between wireline and wireless channels in terms of the importance of various
resources should be understood.
 Identify practical technologies around us that use the design ideas identified in the course, and
how the general principles developed in the course can be used to design myriad emerging
informational technologies.
Brief Technical Description
Communication systems are the basic building blocks of the information age, supporting technologies
from social media to data analytics and allowing people to stay connected. Examples include high-speed
communication networks, wireless and wireline telephone systems, high-speed modems, and visible
light communication. Claude Shannon’s 1948 paper demonstrated there is a common currency of
information, measured in bits. Building on this insight, this course is centered on a single theme:
reliably and efficiently communicate information over an unreliable physical medium
The emphasis is on how to transfer information between a transmitter-receiver pair. The transfer
involves a physical medium, whose input-output characteristics are not deterministically known. The
curriculum has three broad parts.
 Channel Model: Even though the input-output relationship of the physical medium is not
deterministically known, statistical quantities of this relationship, such as mean and correlation,
can be physically measured and are typically constant over the time-scale of communication.


Transmission and Reception Strategies: The statistical model of the physical medium is then
used in the engineering design of appropriate transmission and reception strategies (modulation
and demodulation).
Design Resources and Performance: The resources available to the communication engineer are
power and bandwidth. The final part of the course is to relate the statistical performance of the
communication strategies to these two key resources.
These three parts are discussed in the context of three specific physical communication media.
 Additive white Gaussian noise channel: The received signal is the transmit signal plus a
statistically independent signal. This is a basic model that models space communications and
also underlies the more complicated wireline and wireless channels.
 Telephone channel: The received signal is the transmit signal passed through a time-invariant,
causal filter plus statistically independent noise. Voiceband v.90 modem and DSL technologies
are examples.
 Wireless channel: The received signal is the transmit signal passed through a time-varying filter
plus statistically independent noise. The GSM and 1xEV-DO standards are examples.
Requirements
Homeworks (14%), two midterm examinations (25% each), a final examination (35%), and class
participation (1%). Note that all homework will be due in class.
Text and Reference Material
There is no required textbook for this course. We will provide detailed lecture notes by Prof. Pramod
Viswanath and they will be available in hard copy at the ECE Store. The following draft textbook can
provide an alternate perspective:
•
U. Madhow, Introduction to Communication Systems
The following texts are at the graduate level, but can provide enrichment and examples.
•
U. Madhow, Fundamentals of Digital Communication
•
J. M. Wozencraft and I. M. Jacobs, Principles of Communication Engineering
•
J. G. Proakis, Digital Communications
•
A. Lapidoth, Foundation in Digital Communication
Detailed Course Outline
The course is divided into three parts. The first part will cover reliable communication over additive
Gaussian noise channels, the second over wireline channels, and the last over wireless channels. A
detailed outline of the first several lectures (comprising the first part) is provided below. This detailed
outline may be updated slightly as we go.
January 19*
January 21*
January 26*
January 28*
February 2*
(Lecture 1) Discrete Nature of information
HW1 assigned
(Lecture S1) Data Compression
(Lecture 2) Statistical Channel Model
(Lecture 3) Histogram to Optimum Receiver
HW1 due in class
(Lecture 4) Sequential and Block Communication
HW2 assigned
February 4*
February 9*
February 11*
(Lecture 5) Energy-Efficient Communication
(Lecture 6) Rate-Efficient Reliable Communication
(Lecture 7) Reliable Communication with Erasures
HW2 due in class
February 16*
(Lecture 8) Capacity of the AWGN Channel
HW3 assigned
February 18*
(Lecture 9) Pulse Shaping and Sampling
February 23*
(Lecture 10) Capacity of the Continuous time AWGN Channel
February 25
(Lecture S2) Buffer / Review
HW3 due in class
March 1
Exam 1
March 3
(Lecture 11) Modeling the Wireline Channel: Intersymbol Interference
HW4 assigned
March 8
(Lecture 12) Intersymbol Interference Management: Low SNR Regime
March 10
(Lecture 13) Intersymbol Interference Management: High SNR Regime
HW4 due in class
March 15
(Lecture 14) Interference Management at all SNRs
HW5 assigned
March 17
(Lecture S3) Review of Fourier Analysis
March 22
Spring Break
March 24
Spring Break
March 29
(Lecture 15) Transmitter-Centric ISI Management: Precoding
March 31
(Lecture 16) Transmitter-Centric ISI Harnessing: OFDM
HW5 due in class
April 5
(Lecture 17) OFDM and Capacity of the Wireline Channel
HW6 assigned
April 7
(Lecture 18) Passband Wireless Communication
April 12
Exam 2
April 14
(Lecture 19) The Discrete Time Complex Baseband Wireless Channel
April 19
(Lecture 20) Sequential Communication over a Slow Fading Channel
HW6 due in class / HW7 assigned
April 21
(Lecture 21) Typical Error Event in a Slow Fading Wireless Channel
April 26
(Lecture S4) Sociotechnical Systems, Human Attention, and Surprise
April 28
(Lecture 22) Time Diversity
HW7 due in class
May 3
(Lecture 23 and 24) Frequency and Antenna Diversity
May ?
Final Exam
* If needed, one of these classes will become a review of probability and lecture topics will shift down by
one session. If not needed, February 25 will review communication on AWGN channels.
Emergency Response Recommendations
The Department of Homeland Security and the University of Illinois at Urbana-Champaign Office of
Campus Emergency Planning recommend the following. In an emergency in this building, we’ll have
three choices: RUN (get out), HIDE (find a safe place to stay inside), or FIGHT (with anything available to
increase our odds for survival).
First, take a few minutes this week and learn the different ways to leave this building. If there’s ever a
fire alarm or something like that, you’ll know how to get out, and you’ll be able to help others get out
too. Second, if there’s severe weather and leaving isn’t a good option, go to a low level in the middle of
the building, away from windows.
If there’s a security threat, such as an active shooter, we’ll RUN out of the building if we can do it safely
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If you have any questions, go to police.illinois.edu, or call 217-333-1216.