Digital Communications - TCOM 551 & ECE 463

Transcription

1 Digital Communications - TCOM 551 & ECE General George Mason University Pre-Requisite: TCOM 500 Term Spring 2010 Time: Tuesdays, 4:30-7:10 p.m. Schedule: Jan. 19 to May 11 Location: Innovation Hall, Room 203 Instructor: Dr. Seema Sud Contact Information: ssud@gmu.edu (preferred) or (703) Office Hours: Tuesdays, 3:30 p.m. - 4:30 p.m. (please or call if you would like to see me during office hours), or by appointment Office: Engineering Building, Room 3707 College-level mathematics above Analytical Geometry is not required, although students will be expected to learn, and master, design concepts that require some numerical manipulation. The first lecture will provide most of the mathematical concepts that will form the basis for understanding the design of digital links. This course is required for all students who wish to take Satellite Communications (TCOM 607) and Advanced Link Design (TCOM 707). It is also useful for Mobile Communications (TCOM 552). Coupled with network classes, the course enables students to be comfortable with design concepts from distributed wireless networks, to WiMAX, to satellite systems (FSS and VSATs). 2. Required Textbook Title: Digital Communications (Note: this is a paperback book with a CD ROM) Author: Andy Bateman Publisher: Addison Wesley Longman 1999 ISBN No Additional Reading (not required): Title: Communications Systems Volume-1 Fundamentals Author: Harold Kolimbiris Publisher: Phaeton Press 2008 ISBN No Calculator Students should have a calculator, or a PDA (or equivalent) with a calculator option. The calculator shall have the following functions: LOG, 10 x, sin, cos, tan, sin -1, cos -1, tan -1. A number of examples in class will require the conversion from normal numerical values into logarithms (i.e. log 10 ), and vice versa, in addition to using the standard geometrical functions sine, cosine, and tangent. Advanced calculators that store equations and other processes will not be permitted in

2 exams. Please make sure you have only a simple calculator for the closed book, closed notes tests and final exam. You will be allowed to bring a one page (front only) formula sheet. This sheet must only contain formulas and constants. The emphasis is on understanding concepts rather than memorization. 4. Lecture Notes & Homework Power Point slides for the lectures will be distributed by to the class at least one day prior to each lecture. Students are encouraged to review the notes prior to class. Homework will be assigned regularly except for the week before an exam. The purpose of the homework is to reinforce what is taught in class and provide practical, in depth examples. Students are encouraged to collaborate on homework but it will not be graded for credit. However, you are strongly encouraged to work each homework problem to help you prepare for exams. Homework solutions will be provided. 5. Tests & Final Exam Two tests and a final exam will be given (in class) during the semester. They will be closed book, closed notes tests of about two hours each. The first test will cover class work up to and including the lecture prior to the day of the first test. The second test will cover class work that has been done after the first test and up to and including the lecture prior to the day of the second test. The final exam will concentrate on class work after the second test (80%), but it will also include some questions on earlier parts of the course. You are allowed to bring a one page formula sheet (front only) to each exam. This sheet must contain only formulas and constants. You should also bring a pen or pencil, paper, and calculator. No other materials are allowed, and all material, including your formula sheet, is to be turned in to the instructor at the end of the exam period. 6. Term Paper It is encouraged that, while each student must independently develop a response, students seek and provide comments for each other s approach. This collaboration is characteristic of the actual engineering design environment. The project for this semester will be a 5-15 page research assignment. You are free to choose any topic that interests you, but if your topic differs greatly from the suggested ones, you must clear it with me first in the form of a ½ to one (1) page proposal submitted in writing within three weeks of the date that the project is assigned. The proposal must clearly state the purpose of the proposed work and how it relates to the course material, the method of study, and the desired results/outcome. You are encouraged to use any and all available resources, but all resources must be properly cited. Failure to properly cite referenced material is a violation of the university honor code. You also have the option to give a minute talk on the topic of your choice in lieu of submitting a written paper. Please let me know if you choose this option. Presentations will be at the beginning of the last class. Students will be required to submit a term paper on a topic of their choosing that is in the general field of digital communications. The paper should be on the order of pages long. Example topics are: - Which MA method is better in certain applications, and why: TDMA or CDMA? - What was the impact of MPEG-2 on video communications? - What does LD-CELP mean and how has it revolutionized the transmission of voice traffic? - In what ways is digital TV better than Analog TV, or vice versa? - What is a smart antenna and how will it help us in wireless communications?

3 - What is the impact of spectrum congestion on new services and existing services? - How has digital imaging and digital manipulation impacted sports broadcasting and production procedures? - What digital technologies are set to impact video film production and distribution? - Why did direct broadcast satellite services fail when analog modulation was used but succeed when digital modulation was used? - What is UWB? - Why is PPM becoming important for long distance optical communications? - What are useful measures of spectrum efficiency? - What are software-defined radios? - Is an optical back-plane a feasible switching option yet? - What are the differences between the US GPS and the European Galileo system? The term paper is a way of getting students used to writing a technical paper that will almost certainly be required in their careers. The term paper shall be written with the following basic format: 1.5 or double-spaced lines, single-sided pages, font, size 10 or 12. Please use the IEEE standard guidelines (ieee.org) for citing references. Please limit the use of web references. Review of the literature is mandatory; I expect you to cite at least three papers published in journals or conference proceedings, or books as background work for the project. It is expected that you cite previous works properly, including websites. The resource Turnitin.com shall be used to review term papers for plagiarism. The term paper will not be allocated specific marks. However, a student who does not hand in a paper, or turns in a failing paper, will have the score of his/her final exam cut in half. That is, a score of 90% will become a 45% score in calculating the final grade. The term paper will be due two weeks before the final exam, i.e. April 27 before 11:59 p.m. Please submit papers in soft copy format before the due date. Late papers will not be accepted, no exceptions. 7. Course Grade Final Grades will be determined by a weighted average of the two tests and final exam in the following manner: Test 1 & 2-30% each; Final Exam - 40% The George Mason University honor code will be strictly enforced. 8. Course Outline (Subject to Change) Note: the reference pages for Kolimbiris are for his earlier book Digital Communications with Satellite and Fiber Optic Applications Author: Harold Kolimbiris Publisher: Prentice Hall 2000 ISBN No Lecture 1: January 19 Introduction to course; Sine wave review (concepts of phase, frequency, wavelength); logarithm review (need for conversion to log values); why use db?; review of communications concepts such as C/N, S/N, BER; difference between performance and availability; etc.

4 Lecture 2: January 26 Concept of Noise and Bandwidth, and their impact on communications systems; Boltzmann s constant = k; System Noise Temperature = T sys ; Noise Power = k T sys B watts, where B = bandwidth; concept of baseband and passband signals. Kolimbiris Chapter 1; Bateman Pages 11-13, Lecture 3: February 2 The Building Blocks of a Communications System; Transmission side: source, source coding, information signal, channel coding, modulation, multiplexing, IF, mixer, RF, transmitter, antenna; Receiving side: antenna, low noise amplifier, mixer (RF to IF), amplifier, demodulation, demultiplexing, decoding, sink. Kolimbiris Chapter 3; Bateman Pages 25-28, 162, 172 Lecture 4: February 9 The Building Blocks of Networks Digital Multiplexing: FDM and TDM concepts; multiplexing hierarchies; statistical multiplexing and Digital Speech Interpolation; Kolimbiris elements of Chapter 4; Bateman Pages 16-24;Class Notes Lecture 5: February 16 Digitization: conversion of an analog signal into a digital signal; sampling theorem, quantization noise, aliasing, digitization (quantization, bits per sample, line codes, etc.), compression laws. Kolimbiris Chapter 2; Bateman 24-25, 67-70, 91-93, Lecture 6: February 23 Test No. 1 Link Budget I line of sight microwave links; antenna design, gain, beamwidth; EIRP and calculation of overall System Noise Temperature; Frésnel zone; path loss; development of link budget. Kolimbiris Chapter 4 and elements of Chapter 6; Bateman Pages Lecture 7: March 2 Link Budget II Amplifiers; linearity, saturation, output back-off, and input back-off; examples of other digital systems (optical fibers, satellites) Kolimbiris Chapter 4 and elements of Chapters 8, 9, & 10; Bateman Pages Spring Break: March 9 (No Class) Lecture 8: March 16 Filtering and Interference Issues; root raised cosine filters; baseband bandwidth and pass band bandwidth; filter roll off; Inter Symbol Interference; Nyquist filtering; Sinc functions [(sin x)/x] Bateman Pages 8-11, 50-59, Lecture 9: March 23 Digital Modulation I: the concept of modulation; amplitude modulation, frequency shift keying, phase shift keying; bits per symbol; modulation index; higher order modulations; Kolimbiris elements of Chapter 3; Bateman Pages 36-46, ,

5 Lecture 10: March 30 Digital Modulation II: Advanced modulation concepts; trellis code modulation; QAM; synchronization aspects; frequency locking; phase locking; Kolimbiris elements of Chapter 3; Bateman Pages 36-46, 59-61, , ; Lecture 11: April 6 Test No. 2 Multiple Access I: FDMA, ALOHA, TDMA, and CDMA Kolimbiris elements of Chapter 7; Bateman Pages Lecture 12: April 13 Multiple Access II: FDMA, ALOHA, TDMA, and CDMA (contd.) Kolimbiris elements of Chapter 7; Bateman Pages Lecture 13: April 20 Channel Coding: FEC, block codes, Hamming codes, Hamming distance, convolutional codes, hard decision/soft decision decoding Bateman Pages Lecture 14: April 27 Propagation Effects: line-of sight phenomena multipath, rain attenuation, rain depolarization, scintillation; non-line of sight phenomena diffraction, over-the-horizon effects; impact of atmospheric particles (e.g. rain drops) absorption effects on system noise temperature Kolimbiris elements of Chapter 4; Bateman Pages Reading Day: May 4 (No Class) Final Exam: May Acknowledgment Much of the material used in this course is based on notes provided by Dr. Jeremy Allnutt. All material is used with permission of the author and is not to be reproduced without permission from the author. 10. Additional Information If you are a student with a disability and you need academic accommodations, please see me and contact the Disability Resource Center (DRC) at (703) All academic accommodations must be arranged through the DRC. There is a continued concern about safety and security on campus. We encourage students to sign up for the Mason Alert System, which can provide timely emergency information, by visiting the website Students are also reminded that an emergency poster exists in each classroom explaining what to do in the event of crises. Further information about emergency procedures exists on