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ECE 361 - Digital Communications

Spring 2021

Subject Area


Course Director


Addresses the reliable communication of one bit of information over three types of channels: additive Gaussian noise, wireline, and wireless. Emphasis is placed on the impact of bandwidth and power on the data rate and reliability, using discrete-time models. Technological examples are used as case studies.

Detailed Description and Outline

Communication Systems are the basic workhorses behind the information age. Examples include high speed communication networks, wireless and wireline telephone systems, high speed modems, etc. The basic currency of information is digital: bits. Broadly speaking, this course is centered around a single theme:

reliably communicate bits over an unreliable physical medium.

The emphasis is on how to transfer this currency between a transmitter-receiver pair. The transfer involves a physical medium, whose input-output characteristics are not deterministically known. The curriculum has three broad parts:

  • Transmission and Reception Strategies: The statistical model of the physical medium is then brought into bearing in the engineering design of appropriate transmission and reception strategies (modulation and demodulation, in the language of this course).

  • Design Resources and Performance: The resources available to the communication engineer are power and bandwidth.

  • The final part of the course is to relate the statistical performance of the communication strategies to these two key resources.

These three parts are discussed in the course in the context of three specific physical media:

  • Additive white Gaussian noise channel: The received signal is the transmit signal plus a statistically independent signal. This is a basic model that underlies the more complicated wireline and wireless channels.

  • Telephone channel: The received signal is the transmit signal passed through a time- invariant, causal filter plus statistically independent noise. Voiceband v.90 modem and DSL technologies are used as examples.

  • Wireless channel: The received signal is the transmit signal passed through a time- varying filter plus statistically independent noise. The GSM and 1xEV-DO standards are used as examples.


detailed course notes available

Required, Elective, or Selected Elective


ABET Category

100% Engineering Science

Course Goals

This course is aimed at introducing the fundamentals of digital communication to (junior) undergraduate students. The background expected includes a prior course in signals and systems (usually ECE 210 though it would be great to have concurrent registration in ECE 410) and familiarity with statistical and probabilistic methods (ECE 313). The goals of the course are to familiarize the students with the modeling, design and performance analysis of digital communication systems over two very common physical media: wireline and wireless channels.

Instructional Objectives

At the end of the course, the students should be able to:

  • Reason out and arrive at appropriate statistical models for random physical phenomena. Specifically, this should be done for wireline and wireless channels. Further more, within wireless, terrestrial and deep space models are of interest. (a), (b), (c), (e), (i), (k), (l).

  • Translate the statistical modeling of the physical media into design strategies at the transmitter and the receiver. This should be done, specifically, for both the wireline and wireless channel models arrived at earlier. (a), (d), (e), (i), (l), (m), (n).

  • Understand the relation between the resources (bandwidth and power) and perfrmance criteria (data rate and reliability). This should be specifically done for the wireline and wireless channels. The key difference between wireline and wireless channels in terms of which resource is worth what should be understood. (a), (c), (d), (i), (m), (n).

  • Finally, be able to identify practical technologies around us that use the design ideas identified in the course.(a), (c), (f), (g), (h), (i), (j).

Last updated

5/23/2013by Pramod Viswanath