1

ENSC327/328Communication Systems

Course Information

Paul HoProfessor

School of Engineering ScienceSimon Fraser University

2

Schedule & Instructor Class Schedule:

Mon 2:30 – 4:20pm AQ 3159 Wed 1:30 – 2:20pm AQ 3159 (Tutorial) Wed 2:30 – 3:20pm AQ 3159

ENSC328: Students in ENSC 328 only need to attend three weeks of lectures, tentatively from

Oct. 24 to Nov. 16 (will confirm via emails)

Instructor: Paul Ho (pho@sfu.ca, ASB9835, 778-782-3822) http://www.ensc.sfu.ca/people/faculty/ho/ENSC327/ Office hours:

11:30am – 1:20 pm, Wednesday, or by appointment. Research areas:

Wireless communications, detection and estimation, signal processing

3

TAs Ali Zarei

Responsibilities - assignment consultation and marking TA Hours and location - Tuesday 2:30-4:30 pm, TA room

in 10814 Hanieh Khalilian

Responsibilities - assignment consultation and marking TA Hours and location - Monday 12:30-2:30 pm, TA room

in 10814 Homa Eghbali

Responsibilities - lab consultation and marking TA Hours and location - Thursday 12:30-2:30 pm,

undergraduate communications lab in 10820

4

Textbook, Website & Courselist S. Haykin, M. Moher,

An Introduction to Digital and Analog Communications, 2nd Edition, Wiley, 2007.

Not needed by ENSC328.

5

Textbook, Website & Courselist

Course webpage: http://www.ensc.sfu.ca/people/faculty/ho/ENSC327/ Notes:

Contains main ideas only; details filled in during lectures

Assignments User manuals for lab equipment

6

ENSC327 Grading This course will be graded on a curve.

ENSC327 Grade breakup: Assignments (7 or 8 times): 15% Labs (3): 10% Midterm: 30% Final: 45%

Midterm exam: Monday Oct. 31 (tentative) Final exam: Dec 12, 2011

Assignments and lab reports should be submitted to the assignment drop box out of the ENSC department office (ASB Atrium).

Penalty for late submission of homework: 25% per calendar day. Late submissions should be submitted to Dr. Ho directly (otherwise it will only

be picked up with the next homework, resulting in more penalty)

7

ENSC328 Grading ENSC328 Grade breakup:

Assignments (2-3 times): 25% Final: 75%

Final exam (1.5 hours): Thursday Dec. 1 (tentative)

I will NOT change the grading policy for any student who don’t do well in the midterm exam or final exam. It’s unfair to other students. Please don’t try to negotiate this with me.

8

Exam Format This is a fundamental course for many other courses in digital

communications.

Exams for both ENSC327 and ENSC328 are opened book

CELL PHONE IS ALLOWED. I will try to design the exam questions so that you don't even need calculator at all.

Anybody who is caught using cell phone in the exam for any purpose (including watching the time) will fail the course immediately. If you want to know the time, use your watch or ask us.

The exams focus on the understanding of the theory, instead of pure calculation: Example: Prove some important results that were studied in the lectures.

9

Makeup Exam A makeup exam will be arranged if you miss the midterm or

final exam due to a documented health problem or family catastrophe. Your Doctor’s excuse note must contain the following:

Doctor’s contact information Your name The date the note was written Reason for you to skip the exam.

Please contact me in advance or within 12 hours after the exam if you have to miss the exam, otherwise you will receive a zero grade.

Caution: The number of questions and the difficulty of the makeup exam could be different from the original one, depending on when the makeup exam will be given, how many students will take it, and other relevant information.

10

Plagiarism Please review the SFU plagiarism page:

http://www.lib.sfu.ca/researchhelp/writing/plagiarism.htm

An assignment containing copied material from others will receive 0 (for both students) Second-time offender will get an F.

Cheating on an exam will receive an F.

11

Collaboration on Homework Assignment

It is ok to discuss the homework questions with other students

BUT do not read other people’s solutions. Write your own answers and the codes.

For the simple Matlab or simulink questions we have in this course, it makes no sense to write it together with other students.

12

Labs Lab Topics:

Lab 1 (Week 1): Spectrum analyzer (report not needed, please finish by Sept. 28) Lab 2 (Week 4): Amplitude modulation Lab 3 (Week 7): Direct FM Lab 4 (Week 10): Indirect FM

LabVolt Analog Communications Modules: http://www1.labvolt.com/publications/Datasheets/Current2/dsa9410.pdf

Room: ASB 10820 Communications Lab Access code will be emailed to the class. Access card required. Email ensc-res@sfu.ca if you don’t have one. Opened 24 hours Signing-up sheet will be distributed before each lab. TAs are available during their office hours.

Lab Groups: 4 students / group Please email me your group member information before Sept 28 (when Lab 2 starts)

13

MATLAB Simulink Homework includes some MATLAB programming

and Simulink assignments.

Simulink: A block diagram-based MATLAB extension that allows

engineers to rapidly and accurately build computer models of dynamic systems.

The simulink diagrams can be converted to C codes, which can be compiled for different target platforms.

14

An Example of Simulink

Block diagram Scope output Spectrum analyzer output

Type “simulink” from MATLAB command line to launch the simulink window.

A short tutorial will be distributed with the first Simulink assignment.

15

ENSC MATLAB Licenses Simulink: 50 users Communications Blockset: 20 usersDSP Blockset: 20 users (Including the FFT block for spectrum analysis)

Communications: 20 users Real-Time Workshop: 50 users Signal Processing: 50 users Please start working on your assignment

earlier to avoid license problem.

16

Question?

17

Block Diagram of a Comm SystemInput

Input message may not be suitable for transmission directly e.g., may need to be sampled and compressed (my research area)

Transmitter: make the signal suitable for transmission By modulating a carrier signal: change its amplitude, phase, or frequency

Channel: air, phone line, coaxial cable, power line, optical cable…… Noise can be introduced during transmission Different channels and noises have different characteristics

Receiver: recover (demodulate) the message signal The transmitter and the receiver are jointly designed.

Modem: The combination of Modulator and Demodulator

Covered in this course

18

Primary Resource and Operational Requirements The two primary communication resources:

Transmitter power Channel bandwidth:

US wireless channel license fee: ~ $77 billions / year

The performance of the system is also affected by the noise Signal-to-noise ratio (SNR):

Joint effect of the signal power and noise power The design of a communication system is a tradeoff between

SNR and channel bandwidth. To improve the performance of a system:

If there is a limitation on bandwidth, we can increase the SNR (easier) If there is a limitation on SNR, we can increase the bandwidth (more

difficult)

19

Examples

Telephone: 1875 by Bell AM Radio (amplitude modulation): 1906 by Reginald Fessenden

The father of radio broadcasting. Holder of 500 patents Worked for Thomas Edison in NY the first audio transmission by radio (1900), the first two-way trans-atlantic radio transmission (1906), the first radio broadcast of entertainment and music (1906). http://en.wikipedia.org/wiki/Reginald_Fessenden

FM Radio (frequency modulation): 1933 by Armstrong Television: 1928 Computer networks Satellite communications Optical communications Data storage: needs powerful encoding and decoding techniques

20

Topics Analog Communications (6 weeks)

Linear modulation: AM, SSB, VSB

Angle modulation: PM and FM Pulse modulation

Random processes (3 weeks) (together with ENSC 328) Autocorrelation Power spectral density

Basic digital communications (3 weeks) Baseband digital communications: Nyquist condition Band-pass modulation Basic detection theory

These theories are essential to understand more advanced topics in communications: CDMA, OFDM, UWB, MIMO, WiMAX, ……

21

Mathematical Tools For Comm Calculus, Linear Algebra Signals & Systems (ENSC380)

Fourier Transform (1822) Probability (STAT270) Stochastic Processes (STAT380)

Will be covered in this course (3 weeks) Digital Signal Processing (ENSC429) Statistical Signal Processing (ENSC802)

Usually taught at graduate level Based on Probability and Stochastic Processes Pioneered by Norbert Wiener in 1940’s

Wiener: Went to college at age of 11, Got PhD from Harvard at 18 Information Theory and Coding

Usually taught at graduate level Also based on Probability and Stochastic Processes Established by Claude Shannon in 1948

These tools are also useful in many other areas

22

Mathematical Tools For Comm Usage of Fourier Analysis: s(t): source signal (e.g., speech or audio signal)

where frequency fc is much higher than the frequency of s(t). This is called double sideband suppressed carrier (DSB-SC)

modulation

What is the bandwidth of y(t)? Can be easily answered by Fourier analysis.

)2cos()()( tftsty cπ= s(t)

)2cos( tfcπ

y(t)

23

Mathematical Tools For Comm In this course, we usually assume s(t) is a sinusoidal

signal itself Trigonometric identities will be extremely useful in the

first half of the course Will NOT be provided in the exam!

Example:( )( ) ( )( )1 2 1 2 1 2

1cos( ) cos( ) cos cos2

t t t tω ω ω ω ω ω = + + − The frequency components of the signal can be easily identified.

This is an example of modulation. The trigonometric identities are also useful in demodulation

to get back the signal s(t) at the receiver.

24

Mathematical Tools For Comm Probability is very useful for the second half of the course:

m(t)

n(t)

+ )()()( tntmtr +=

m(t): 1 or -1 (binary) n(t): zero-mean, unit variance Gaussian noise.

Given the received signal r(t), how to estimate the signal? What is the probability of the decoding error?

Will be solved in this course by probability knowledge.

25

Caution Our lecture notes are not exactly the same as the textbook

Some materials in my notes are not in the book, and vice versa.

The first priority is to understand the notes.

EVERYTHING in my notes can appear in the exam, even if it is not in the book.

The topics in the book that are not covered in my notes will NOT appear in the exam.