525.783.81 - Spread Spectrum Communications

Expanded Course Description

Prerequisites 525.616 Communication Systems Engineering. Students should have knowledge of material covered in 525.201 Circuits, Devices, and Fields and 525.202 Signals and Systems.

Course Structure

The course materials are divided into modules which can be accessed by clicking Modules on the course menu. A module will have several sections including the overview, content, readings, discussions, and assignments. You are encouraged to preview all sections of the module before starting. Most modules run for a period of seven (7) days, exceptions are noted in the Course Outline. Go to the bottom of the modules page and pay attention to the supplemental files.

Course Topics

1. Intro to spread spectrum
   
2. Orthogonal sequences, spread spectrum example
3. Review of radio design
4. Sequences and finite fields
5. Generator functions, Gold codes, and Correlators
6. Cryptography and Error Correction
7. Cryptography and Error Correction Project
8. Code-Tracking and Phase-Locked Loops
9. Code Acquisition and Non-Linear Dynamics
10. Global Positioning System Spread Spectrum Receivers
11. Wireless CDMA Telephone Systems
12. Access Protocols for Spread Spectrum Systems
13. Final Exercise
14. Summary and Review

Course Goals

• To analyze, based on computations, and simulations, the predicted performance of spread spectrum systems, including the Global Positioning System, in terms of processing gain, link margin, anti-jam, acquisition and tracking times, and system capacity
• Explain the similarities and differences between spread spectrum systems and radios and their non-spread spectrum counterparts
• Explain the differences, in design, implementation, and operation, between code/frequency/time division access and code/frequency/time division multiplexing
• Generate orthogonal codes and pseudorandom noise sequences using both shift registers and generator function representations
• Use pseudorandom sequences for purposes of error correction and cryptography
• Analyze the performance of, and simulate, clock-recovery and signal tracking loops using the principles of nonlinear dynamics

Course Learning Outcomes (CLOs)

• Students will learn the principles of spread spectrum systems, including the Global Positioning System.
• Students will learn the principles of finite fields, orthogonal codes, and pseudorandom noise sequences.
• Students will learn how to use generator functions to generate pseudorandom codes.
• Students will learn how to simulate spread spectrum systems using Excel, Mathcad, Matlab, etc.

Textbooks

Required

Glisic, S., & Vucetic, B.(1997). Spread spectrum CDMA systems for Wireless Communications (1st ed.). Boston, MA: Artech House.

ISBN-10: 0890068585 ISBN-13:978-0890068588

Optional

Lathi, B. & Ding, Z. (2018) Modern Digital and Analog Communication (The Oxford Series in Electrical and Computer Engineering, 5 th Ed). Oxford, UK: Oxford University Press, or other communications text.

ISBN-10: 0190686847 ISBN-13: 978-0190686840
(Note: The 4th edition is fine, if you still have this from 525.616)

Textbook information for this course is available online through the appropriate bookstore website: For online courses, search the MBS website.

Other Materials & Online Resources

Look carefully at all of the supplemental files! They may be very helpful.

Required Software

MATLAB, MathCAD, EXCEL, etc. Although not required, you are free to use the computational software of your choice.

Student Coursework Requirements

In general, it is expected that each class will take approximately 4–7 hours per week to complete. Here is an approximate breakdown: reading the assigned sections of the texts (approximately 1 hour per week) as well as some outside reading, listening to the audio annotated slide presentations (approximately 1–2 hours per week), and writing assignments (approximately 2–4 hours per week).

This course will consist of the following basic student requirements:

Preparation and Participation (15% of Final Grade Calculation)

Each student is responsible for carefully reading all assigned material and being prepared for Discussions. This will include material from the text, course notes provided by the instructor, and some outside reading material that is available on the internet free of charge. Specific URL's will be provided during the semester. The first chapters of the text are noteworthy for their brevity, and must be read carefully. Subsequent, longer chapters are laden with information, but can be read quickly with a view towards understanding the essential background of the topic. This is in contrast to learning all of the nuances of, for example, the IS-95 standard.

Post your response to the discussion forums as appropriate. Posting a response to discussion questions is part one of the grade for class discussions (i.e., Timeliness).

Part two of your grade for class discussion is related to your interaction (i.e., responding to classmate postings with thoughtful responses) with at least two classmates (i.e., Critical Thinking). Just posting your response to a discussion question is not as helpful as interacting with your classmates. You will welcome this interaction when performing complex simulations and solving the cryptography exercise. Be detailed in your postings and in your responses to your classmates' postings. Feel free to agree or disagree with your classmates. Please ensure that your postings are civil and constructive. I will monitor module Discussions and will respond to many, and often most, of the discussions as discussions are posted. In some instances, I will summarize the overall discussions and post the summary for the module.

Evaluation of preparation and participation is based on contribution to discussions.

Preparation and participation are evaluated with regard to the following grading elements:

1. Timeliness (50%)
2. Critical Thinking (50%)

Grading Policy

For reference with respect to other courses you have taken, the following rubric has likely been used. However, a less rigid approach to grading is appropriate for this course, as described below (in the assignment guidelines). This reflects the wide ranges of previous experience of the students enrolled in this course.

Preparation and participation in many EP courses are graded as follows:

100–90 = A—Timeliness [regularly participates; all required postings; early in discussion; throughout the discussion]; Critical Thinking [rich in content; full of thoughts, insight, and analysis].

89–80 = B—Timeliness [frequently participates; all required postings; some not in time for others to read and respond]; Critical Thinking [substantial information; thought, insight, and analysis has taken place].

79–70 = C—Timeliness [infrequently participates; all required postings; most at the last minute without allowing for response time]; Critical Thinking [generally competent; information is thin and commonplace].

​Note that special features of this course and its content are considered as follows:

Participation 15%

Assignments 40%

Cryptography Project 30%

Final Exercise 15%

Course Policies

Resubmissions of assignments and/or individual problems are encouraged in order to facilitate learning.

Homework submission deadlines are flexible.

Academic Policies

Deadlines for Adding, Dropping and Withdrawing from Courses

Students may add a course up to one week after the start of the term for that particular course. Students may drop courses according to the drop deadlines outlined in the EP academic calendar (https://ep.jhu.edu/student-services/academic-calendar/). Between the 6th week of the class and prior to the final withdrawal deadline, a student may withdraw from a course with a W on their academic record. A record of the course will remain on the academic record with a W appearing in the grade column to indicate that the student registered and withdrew from the course.

Academic Misconduct Policy

All students are required to read, know, and comply with the Johns Hopkins University Krieger School of Arts and Sciences (KSAS) / Whiting School of Engineering (WSE) Procedures for Handling Allegations of Misconduct by Full-Time and Part-Time Graduate Students.

This policy prohibits academic misconduct, including but not limited to the following: cheating or facilitating cheating; plagiarism; reuse of assignments; unauthorized collaboration; alteration of graded assignments; and unfair competition. Course materials (old assignments, texts, or examinations, etc.) should not be shared unless authorized by the course instructor. Any questions related to this policy should be directed to EP’s academic integrity officer at ep-academic-integrity@jhu.edu.

Students with Disabilities - Accommodations and Accessibility

Johns Hopkins University values diversity and inclusion. We are committed to providing welcoming, equitable, and accessible educational experiences for all students. Students with disabilities (including those with psychological conditions, medical conditions and temporary disabilities) can request accommodations for this course by providing an Accommodation Letter issued by Student Disability Services (SDS). Please request accommodations for this course as early as possible to provide time for effective communication and arrangements.

For further information or to start the process of requesting accommodations, please contact Student Disability Services at Engineering for Professionals, ep-disability-svcs@jhu.edu.

Student Conduct Code

The fundamental purpose of the JHU regulation of student conduct is to promote and to protect the health, safety, welfare, property, and rights of all members of the University community as well as to promote the orderly operation of the University and to safeguard its property and facilities. As members of the University community, students accept certain responsibilities which support the educational mission and create an environment in which all students are afforded the same opportunity to succeed academically. 

For a full description of the code please visit the following website: https://studentaffairs.jhu.edu/policies-guidelines/student-code/

Classroom Climate

JHU is committed to creating a classroom environment that values the diversity of experiences and perspectives that all students bring. Everyone has the right to be treated with dignity and respect. Fostering an inclusive climate is important. Research and experience show that students who interact with peers who are different from themselves learn new things and experience tangible educational outcomes. At no time in this learning process should someone be singled out or treated unequally on the basis of any seen or unseen part of their identity. 
 
If you have concerns in this course about harassment, discrimination, or any unequal treatment, or if you seek accommodations or resources, please reach out to the course instructor directly. Reporting will never impact your course grade. You may also share concerns with your program chair, the Assistant Dean for Diversity and Inclusion, or the Office of Institutional Equity. In handling reports, people will protect your privacy as much as possible, but faculty and staff are required to officially report information for some cases (e.g. sexual harassment).

Course Auditing

When a student enrolls in an EP course with “audit” status, the student must reach an understanding with the instructor as to what is required to earn the “audit.” If the student does not meet those expectations, the instructor must notify the EP Registration Team [EP-Registration@exchange.johnshopkins.edu] in order for the student to be retroactively dropped or withdrawn from the course (depending on when the "audit" was requested and in accordance with EP registration deadlines). All lecture content will remain accessible to auditing students, but access to all other course material is left to the discretion of the instructor.