A Brief History of Wireless Communications Dept. of Electrical Engeering, POSTECH Joon Ho Cho Welcome to the Exciting World of Information Age! 2 Q. Which major makes all this possible? Father of Information Age 3 Q. Who is the father of the information age? Claude Shannon 4 Q. What was the major of Claude Shannon? Outline 5 Claude Shannon: Father of Information Age This outline Quiz A Brief History of Wireless Communications Quiz 6 Q. , ? Why Communicate? Q. What is the title of the figure shown on the right side painted by Pieter Brueghel in 1563? 7 How to Generate Speech Sound 8 Q. Using the figure shown on the right side, explain how we generate speech sound. Propagation of Sound 9 Q. Using the figures shown on the right side, explain how sound propagates through the air. Dichotomy of Ear 10 Q. Using the figure shown on the right side, explain how sound reaches the brain. Before Invention of Telephone 11 Q. Before the invention of the telephone, how long-distance communication was conducted? 6 Invention of Telephone 12 Q. What was invented by A. G. Bell in 1876? 2 Microphone 13 Q. Explain how a microphone converts sound to current. 3 Loud Speaker 14 Q. Explain how a speaker converts current to sound. 2 How to Support Multiple Subscribers 15 Q. How were multiple subscribers supported? 2 Frequency-Division Multiplexing (FDM) 16 Q. Hinted by rainbow, explain how frequency-division multiplexing works. 2 From Wired to Wireless 17 Q. Explain what it means by from wired to wireless in telecommunications. 3 Wireless Telegraphy 18 Q. Who was the inventor of wireless telegraphy? Amplitude Modulation 19 Q. How does AM work? Noise 20 Q. How can we handle noise? 2 Multipath and Ghost 21 Q. Explain why ghost phenomenon occurs. 2 Frequency Modulation 22 Q. How does FM work? Spectrum as a Scarce Resource 23 Q. How can we increase the spectral efficiency? 2 Turbo Code 24 Q. What is a turbo engine? Multi-Antenna System 25 Q. Why do we have two eyes and two ears? 3 Wireless Communications 26 Q. Which subjects are the foundations of wireless communications? A. Mathematics (Logic, Algebra, Graph Theory, Geometry, Calculus, Real and Functional Analysis, Probability, etc.) Physics (Electromagnetism) 27 Undergraduate Curriculum 28 Graduate Curriculum 28 29 Q. Find the optimal decision rule that minimizes the probability of bit error. Probability Theory 30 Q. Suppose your transmitter emits an EM wave at 1 Watt over a free space. Compute the total power received by a 4piX10cmX10cm aperture 1 km away from the Tx. 3 Random Process 31 Cell Phone Disassembled 31 3 Q. Do you understand what is inside a cell phone? 32 Q. What is going on inside an AM radio? 2-Transistor Solar Panel AM Radio 4 33 Q. How can you design a system? Mathematical Design of Wireless System Conclusions Information technology is a fast evolving exciting area of research and development. 2. Claude Shannon, the father of information age, was an Electrical Engineer and a Professor of the Department of Electrical Engineering at MIT. 3. Wireless communications technology is the heart of the information age. 4. If you love mathematics and physics, wireless communications is the major of your vocation. 5. POSTECH is here to help you fulfill your dream of becoming a best wireless communications engineer/entreprenure.