TAILIEUCHUNG - Digital Communication I: Modulation and Coding Course-Lecture 12

How decoding is performed for Convolutional codes? What is a Maximum likelihood decoder? What are soft decisions and hard decisions? How does the Viterbi algorithm work?The demodulator makes a firm or hard decision whether one or zero was transmitted and provides no other information for the decoder such as how reliable the decision is. | Digital Communications I: Modulation and Coding Course Term 3 - 2008 Catharina Logothetis Lecture 12 Lecture 12 Last time, we talked about: How decoding is performed for Convolutional codes? What is a Maximum likelihood decoder? What are soft decisions and hard decisions? How does the Viterbi algorithm work? Lecture 12 Trellis of an example ½ Conv. code 1 0 1 0 0 11 10 00 10 11 Input bits Output bits Tail bits 1/11 0/00 0/10 1/11 1/01 0/00 0/11 0/10 0/01 1/11 1/01 1/00 0/00 0/11 0/10 0/01 0/00 0/11 0/00 1/01 Lecture 12 Block diagram of the DCS Information source Rate 1/n Conv. encoder Modulator Information sink Rate 1/n Conv. decoder Demodulator Channel Lecture 12 Soft and hard decision decoding In hard decision: The demodulator makes a firm or hard decision whether one or zero was transmitted and provides no other information for the decoder such as how reliable the decision is. In Soft decision: The demodulator provides the decoder with some side information together with the .

• Điện - Điện tử
• digital communication
• multiuser communication
• multicarrier system
• adaptive equalization
• filter channel
• soure coding
• Communication systems
• Digital communication systems