Expert: Cezar L. Palconet - 10/12/2011

Question
Hello sir I am a student doing final year in Btech.The topic for the final year project i have chosen is related to LDPC,and I am really confused where to start from.I have been told to get the logic behind LDPC and I was finding it very difficult,then i came across this site.I thought i could get some help from you.Sir if you don't mind can you just brief out the working of LDPC?
It would be very much useful for me.
Thanks

Answer
Hi,

Do you mean; Low-Density Parity-Check (LDPC) code

This may be way out of my expertise, since my expertise involves RF Frequencies, RF bandwidth and radio networks, nevertheless I will try to point you in the direction you wish to explore, this may not be the one that you are looking for, but this is the limit of my knowledge in this area.

Robert G. Gallager, developed the LDPC concept in his doctoral dissertation at MIT in 1960

LDPC as it was developed was a form of linear error correcting code, it was intended for data transmissions under very noisy channels which is common in multipoint, multipath networks like DVB.

This allows transmissions to be set very close to the noise threshold, or the Shannon’s limit, the channel noise boundary defines the amount of lost bits and can be as small as possible using IBP techniques.
This is used because of its efficient utilization of the bandwidth and where the uplink channels are limited.

You could try reading some of this books which deals extensively on LDPC;

Gallager, R. G., Low Density Parity Check Codes, Monograph,
M.I.T. Press, 1963

Amin Shokrollahi (2003)
LDPC Codes: An Introduction

David J.C. MacKay (2003)
Information theory, Inference and Learning Algorithms,
ISBN 0-521-64298-1

Todd K. Moon (2005)
Error Correction Coding, Mathematical Methods and Algorithms.
ISBN 0-471-64800-0



I Hope this helps,

Regards.