ELEC1200: A System View of
Communications: from Signals to Packets
Lecture 1
• Course Description and Mechanics
• Course Overview
• A basic communication system
– The transmitter
– The channel
– The receiver
ELEC1200
1
Who’s who
Instructor
• Prof. Ross MURCH
Instructional Assistant
• Cupid CHOW
Technical Officer
• Leo FOK
ELEC1200
Teaching Assistants
• INAM ULHAQAZAD
• Zijian LI
• Zhaoyang MING
• Jay Patrick Monton NIELES
• Wenqiang SUN
• Zixi Wan
• Xinyue XU
• Jiuzhou ZHANG
2
Why learn this course?
Hong Kong’s 1st Unmanned car
(ECE Professor, Prof. Ming LIU)
DJI-world’s leader in drones
(ECE former student, Frank Wang)
https://www.ram-lab.com/
•
•
•
ELEC1200
Introduce you to the exciting field of Electronic and
Information Technology field
Learn how to control and manage signal transmission
Learn how networks work and much more…
3
What will you learn?
https://www.bell-labs.com/research-innovation/what-is-6g/#gref
•
•
•
•
•
ELEC1200
How can we transmit information efficiently?
How do we protect information? (coding, security, …)
How radio signals interfere with each others?
How does noise affect communications?
How do we manage the networks? (Wi-Fi, internet, packets,
protocols, routing, …)
4
Course Description
• Have you ever wondered what technologies enable you to communicate
via your mobile phone?
• Course Features
– Hands on: You work with a simple but fully functional wireless communication
system to understand the basic technology in these systems.
– Broad perspective: We cover all aspects of the system from end to end.
– Fundamental: All concepts introduced from first principles. No prior ECE
background is required.
ELEC1200
5
Co-requisites
• Math (one of the following)
– MATH 1003/1014/1020/1024
• Programming (one of the following)
– COMP 1021/1022P
ELEC1200
6
A week in the life of ELEC1200
Mon
Mon
Mon/Wed/Thu
Fri
Lecture A
Tutorial
Lab
Lecture B
• Lectures A and B:
-Cover concepts to be studied in the lab
• Tutorial:
-Discuss examples and prepare for lab
• Lab:
ELEC1200
-Work with hardware or simulations
7
Lab Schedule
• First week (Sept. 1-8) NO lab.
• Second week (Sept. 11, 13 or 14) first lab - MATLAB
– Not a graded lab
– practice MATLAB, lab tasks and post lab quiz
– Please attend your own lab section
– lab #2 - #7 require MATLAB skills
Note: Tutorial 01 will start from the first week (4 Sept.)
ELEC1200
8
Lab Rules
• Attendance at the laboratory is mandatory.
• You must complete at least 5 out of Lab #2 to Lab #7 to obtain a passing grade.
• Your lab score will be computed over all labs regardless of attendance.
• Making up a lab is not allowed, except under exceptional circumstances such as
illness with a valid medical certificate.
All requests for special accommodation for medical reasons must be accompanied by the
hard copy of the original medical certificate.
• Any lab makeup must be completed within two weeks of the scheduled lab time.
ELEC1200
9
Assessment
 Lab (25%)
 Check-off Points (10%)
4 check points (tasks) per lab
 Post-lab quiz (5 minutes) (15%)
open books/notes
No discussion
You must complete all ‘Tasks/check points’ before taking the quiz!!!
 Homework (10%)
 Reinforce concepts learned
 Midterm Exam (25%)
 Final Exam (40%)
ELEC1200
10
Midterm Exam
Midterm Exam (50 minutes)
 L01-L13
Date: 30 October 2023 (Mon)
Time: 17:00 – 17:50 (lecture time)
ELEC1200
11
The most important idea or concept?
Always be Honest and act with Integrity
Plagiarism
Plagiarism is presenting work
which is not your own and
originates from other
sources as if it is your own.
Over the long term being honest and decent will be the most rewarding thing you can ever do!!
ELEC1200
12
Course Objectives
On successful completion of this course, students are expected to be
able to:
1. Examine a voice communication system to identify the practical
context of key theoretical concepts in ECE.
2. Identify typical problems and tradeoffs encountered in electronic
and computer engineering systems.
3. Analyze simple approaches to address a range of problems and
tradeoffs.
4. Use software tools, such as MATLAB, to investigate potential
solutions to problems and tradeoffs in order to validate an analysis,
and to handle cases not amenable to simple analysis.
5. Work in a cooperative setting on real hardware or via simulations
where the simplifying assumptions used in theoretical analysis may
be violated, and assess the benefits and limitations of such analysis.
ELEC1200
13
Our Laboratory Work
Infrared Light
Infrared Light
Headset
ELEC1200
PC + MATLAB
14
Provides the context for:
• Foundation course:
– ELEC2100: Signals and Systems
• Area courses:
– ELEC3100: Signal Processing and Communications
– ELEC3200: System Modeling, Analysis and Control
• Depth Courses
– ELEC41XX
• Digital Communications and Wireless Systems, Machine
Learning on Image, Information Theory and Error-Correcting
Codes
– ELEC4820
• Medical Imaging
ELEC1200
15
What can you do?
As an Engineer:
•
•
•
•
Invent/design/build advanced technology
Solve problems
Improve our lives
Save the world!
https://www.facebook.com/pg/engineeringinsider/reviews/
Imagine!
https://www.theherald.com.au/story/4288160/the-future-is-in-imagination/
ELEC1200
https://www.sciencefocus.com/future-technology/future-technology-22-ideas-about-to-change-our-world/
16
ELEC1200: A System View of
Communications: from Signals to Packets
Lecture 1
• Course Description and Mechanics
• Course Overview
• A basic communication system
– The transmitter
– The channel
– The receiver
ELEC1200
17
Our Question: How to transmit information
wirelessly?
ELEC1200
18
Our Question: How to transmit information wirelessly?
Part 1 of 3: Point-to-point
link from phone
to base station
Part 2 of 3: Sharing a channel
allowing multiple users
Part 3 of 3 Network:
links between base stations
ELEC1200
19
Point-to-Point Communication:
Source
sent
bits
fewer
bits
Compress
more
bits
Error
Correcting
Coding
Bits to
Waveforms
Dest
received
bits
Uncompress
Error
Correction
Waveforms
to Bits
Channel
Labs 2-4
sent
waveform
received
waveform
Noise
and
signals
from
other
users
Labs
5-7
Ideally, “sent bits” = “received bits”
However, this is not always the case.
ELEC1200
20
ELEC1200: A System View of
Communications: from Signals to Packets
Lecture 1
• Course Description and Mechanics
• Course Overview
• A basic communication system
– The transmitter
– The channel
– The receiver
ELEC1200
21
A Basic Communication System
Source
b0,b1,b2, b3, b4, …
Dest
received
bits
Transmitter
Waveforms
to Bits
Receiver
Channel
sent bits
Bits to
Waveforms
sent
signal
received
signal
• The transmitter takes a sequence of bits (0 or 1) and
creates a physical signal or waveform (e.g. time varying
voltage or light intensity) that is carried over a channel.
• The channel (a wire, the air, a fiber optic cable) may modify
the signal as it carries it.
• The receiver tries to figure out what the transmitted bits
were from the received signal.
ELEC1200
22
Bits
• A bit is the basic unit of information used in modern computers and
communication systems.
• A bit is a variable that can assume only two possible values or
“states”, commonly denoted by 0 or 1.
• Intuitively, the bit can be thought of as the answer to a yes/no
question.
• More complicated information can be sent with sequences of bits.
ELEC1200
23
Representing Bits
• Physically, bits can be represented as two
distinct states of a physical variable:
– voltage (1 = high / 0 = low)
– current (1 = positive / 0 = negative)
– light (1 = on / 0 = off)
ELEC1200
24
Representing Bit Sequences as Waveforms
light intensity
• A bit sequence can be encoded by changing the value of the physical variable over
time.
ON
b0=1
b1=0
b2=1
b3=0
b4=0
b5=0
b6=1
b7=0
bit time
OFF
time
light intensity
• Each bit is encoded by holding the state constant over a length of time, known as
the bit time.
• The shorter the bit time, the faster we can transmit information (bits)
ELEC1200
ON
OFF
bit time
25
The channel
• The transmitter sends the waveform representing the bit sequence to
the receiver over a channel.
• For example,
– A voltage or current waveform might be sent over a wire.
– A light waveform might be sent over a fiber optic link (e.g. the internet) or
over plain air (e.g. a TV remote)
• Due to various factors, the channel may distort the waveform, so
that the waveform received by the receiver is not the same as the
one sent by the transmitter.
transmitter
ELEC1200
channel
receiver
26
Receiver
• The receiver’s job is to take the possibly distorted signal it receives
and figures out what the original transmitted bit sequence was.
Source
b0, b1, b2, b3, b4, …
• Common Abbreviations
Channel
Dest
b0, b1, b2, b3, b4, …
Tx
sent
waveform
Rx
received
waveform
– Tx = transmitter
– Rx = receiver
ELEC1200
27
ELEC 1200 & Cutting-edge Technologies
https://data-flair.training/blogs/big-data-applications-various-domains/
https://www.bell-labs.com/research-innovation/what-is-6g/#gref
https://www.expressvpn.com/blog/what-is-the-internet-of-things-iot/
ELEC1200
https://www.codingdojo.com/blog/dark-side-of-artificial-intelligence-ai/
28
Key Questions for Next Three Lectures
• How do we describe the physical waveforms sent by the transmitter
and sensed by the receiver using mathematical equations?
• How do we describe (model) the effect of the channel on the
physical waveform?
ELEC1200
29