Helsinki University of Technology
Communications Laboratory
Timo O. Korhonen
S-72.227 Digital Communication Systems
Study Guide 1: Block Codes
Topics
- FEC systems
- Hamming distance and code quality
- Block codes: generation and detection
- Coding and decoding circuits
General
- What is meant by Hamming distance? Why it is defined?
- Consider code capability to detect and correct errors generally in terms
of Hamming distance!
- Why not use a repetition code?
- How block codes are constructed? The systematic and non-systematic way,
which one to use?
- Why block codes are difficult to decode by following the maximum likelihood
method?
- What are the major benefits of syndrome decoding? Why syndrome must be
independent of the code word? When syndrome decoding can be used?
References
A. Bruce Carlson: Communication Systems III Ed. Sections 13.1-13.2
DAG Instructions
This guide is intended for Discussion Agent Group (DAG) members, but it can be
used also by other students. DAG members should get themselves familiar with the
lecture material and Study Guide well before the lecture and make clear for
themselves the themes they would like to generate discussion. If it appears that
there remains unsolved questions after the session they will be discussed in
next sessions. It is important to note the time reserved for discussion is
maximum of 45 min. only.
Group's tasks
- Group should select session Chair. The role of the session chair is to
give the floor for audience and to guide discussion generally.
- Group should select a secretary whose task is to write down all the
questions and answers popping out at the session. The minutes should be
submitted to the course instructor within two days and it will appear at the
course homepage.
- Lecture themes (from lecture transparencies and study guides) must be
divided to group members such that each member shall carry about the same
workload. Also chair and secretary must participate on drafting the
questions.
Member's tasks
Each group member should
- Make a list of interesting questions/issues she/he knows the answer.
Purpose of these questions is to clarify/underline important topics of the
lecture (from one's personal view)
- Make a list of topics/themes/details that are not understood
- Propose answers to the suggested questions (as listed above)
- Ask the suggested questions from the audience during the session