Broadband Telecommunications Technologies and Management

4Information Theory

Preview Questions

• Is a picture really worth a thousand words? How can one calculate the information content of a picture/a text?
• How long does it take for the Mars Discovery probe to transmit a photo of Martian surface to Earth?
• How can information generated by a source be converted to a binary sequence?
• How does the power of a message signal matter in its accurate transmission and reception?
• How do you calculate the maximum possible transmission rate of a communication system?

Learning Objectives

• Information content measurement
• Source information generation rate and entropy
• Principles of source coding
• Link budget calculation
• Channel capacity calculation

Historical Note

Claude Shannon’s (pictured)¹[1] seminal 1948 paper, ‘A mathematical theory of communication’ [2] is widely considered to be the foundation upon which the fields of information theory and digital communications have been built. The paper is the theoretical foundation which determines how we encode, communicate, and store information in discrete digital form.

Shannon was a researcher at Bell Laboratories, the research arm of the Bell Telephone Company in the middle of the 20th century. At the time a number of communication technologies were known and used: among them were telegraph (Morse, 1844), telephone (Bell, 1876), wireless telegraph (Marconi, 1894), amplitude modulation (AM) radio (Fessenden, 1906), frequency ...