EE 471C / EE 381K-17 Wireless Communications Laboratory

EE 471C / EE 381K-17 Wireless Communications Laboratory

Wireless communication is fundamentally the art of communicating information without wires. In principle, wireless communication encompasses any number of techniques including underwater acoustic communication, semaphores, smoke signals, radio communication, and satellite communication, among others. The term was coined in the early days of radio, fell out of fashion for about fifty years, and was rediscovered during the cellular telephony revolution. Wireless now implies communication using electromagnetic waves — placing it squarely within the domain of electrical engineering.

Thus the spotlight of this class will focus on digital wireless communication. Every major wireless system being developed and deployed is built around digital communication including cellular communication, wireless local area networking, personal area networking, and high-definition television. This class is unique because it approaches wireless communication from the perspective of digital signal processing (DSP). No background in digital communication is assumed, though it would be helpful. The utility of a DSP approach is due to the following fact: wireless systems are bandlimited. This means that with a high enough sampling rate, thanks to Nyquist’s theorem, it is possible to represent the bandlimited continuous-time wireless channel from its samples. Further,  it is possible to treat the transmitted signal as a discrete-time sequence, the channel as a discrete-time linear time-invariant system, and the received signal as a discrete-time sequence.

This course takes an experimental approach to wireless digital communication. Theory in the classroom is translated directly into practice with the help of the Ettus USRP software defined radio platform and using the MATLAB Universal Hardware Driver. The emphasis is on physical layer concepts rather than implementation considerations. A three-hour laboratory period will complement the usual three-hour lecture period each week.

Information for the most recent version of the course (Fall 2018) is provided as follows.

Syllabus EE 471C

Lab Outline EE 471C

Lab Outline EE 471C

Term project EE 381K

The course follows the instructor’s textbook

Robert W. Heath Jr.,  Introduction to Wireless Digital Communication: A Signal Processing Perspective, Pearson Education, Inc. 2017.

Specific topics covered in this course in the lecture and laboratory include

  • Bandwidth, sampling, complex baseband equivalent representation
  • Upconversion, downconversion, narrowband signals
  • Single carrier quadrature amplitude modulation
  • Probability of symbol error in Gaussian and fading channels
  • Channel estimation
  • Linear equalization
  • Frame, symbol, and carrier frequency offset synchronization
  • Single carrier frequency domain equalization using cyclic prefixes or zero padding
  • OFDM modulation including channel estimation, synchronization, and equalization
  • Small scale fading, large scale fading, link budgets
  • Principle of diversity
  • Receive diversity, selection diversity, and maximum ratio combining
  • Transmit diversity and the Alamouti code
  • MIMO communication systems including spatial multiplexing
  • Dealing with impairments in MIMO communication systems
  • Introduction to array signal processing
  • Advances in MIMO including massive MIMO and millimeter wave MIMO
  • Applications of theory in IEEE 802.11a and IEEE 802.11ad

This class is different from other offerings at UT Austin and is generally unique throughout the world. Here is a brief comparison with other courses at UT Austin:

  • EE 445S Real-time Digital Signal Processing deals particularly with real-time implementation issues, DSP architectures, etc. QAM modems are used as a significant design example but digital communication is not the focus of the course. In EE 371C I assume that you already know the basics of DSP (thus the DSP prerequisite). The emphasis will be on using your existing DSP toolset to build a real wireless modem. Along the way you will learn about propagation, synchronization, digital receivers, OFDM, and current wireless standards like IEEE 802.11a and GSM. Programming will be done in LabVIEW thus there will be less concern for real-time DSP implementation.
  • EE 360K Digital Communication deals with the principles and theory of digital communication. You deal with topics like signal space, modulation, maximum likelihood detection, and bit error rate analysis. In EE 371C we focus on wireless digital communication, but with an emphasis on building a complete wireless digital communication system in the lab. Thus we deal with the whole physical layer system. In particular we discuss modulation, demodulation, bit error rate analysis, frame synchronization, symbol synchronization, frequency offset correction, and OFDM modulation. We cover a little about each topic, to provide intuition and a foundation for future work. Consequently we don’t cover as much digital communication theory, instead focusing on a few key algorithms that we will implement in the lab. We also discuss current standards like IEEE 802.11a, GSM, and IEEE 802.11n. NOTE: It appears that EE 360K will not be taught in 2014-2015. EE 471C / EE 387V is an excellent alternative.

This course grew out of my own experience prototyping wireless systems. I think that actually building a communication link reveals the importance of each component of the system. It provides intuition that becomes a foundation for taking advanced course in wireless or for becoming a practical wireless engineer.

This course was designed, tested, and implemented at The University of Texas at Austin over the past fifteen years. An older version of the laboratory manual is packaged with one of National Instruments’ USRP bundles and the course is offered by universities worldwide! A new version of the course materials are being developed to work in MATLAB. The first version was tested in Fall 2018.

The Wireless Communications Lab fulfills a Technical Area elective in the Communications / Networking area and the Signal / Image processing area.

Note about the graduate cross-listed version EE 381K-17. The graduate realization of this course, additionally requires a final term project. As a result, it is graded differently than EE 471C. Details on the final project and grading criteria can be found Term project EE 381K. Graduate students: please note that this course covers several topics that are not taught in any other graduate course at UT Austin including:

  • Channel estimation
  • Software defined radio
  • Frame, symbol, and carrier frequency offset synchronization
  • Single carrier frequency domain equalization using cyclic prefixes or zero padding
  • OFDM modulation including channel estimation, synchronization, and equalization

Course Lectures from Fall 2014

Below I provide videos of the lectures from the Fall 2014 course offering, along with scanned lecture notes. These are the straight video recordings without audio-video wizardry or multiple retakes. Occasionally a mistake made was corrected in a subsequent lecture.

Wireless News

LabVIEW Links

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