hello i am student doing in raptor codes for encoding and decoding as i am not getting enough guidance??can you help me if you know??And send that related codes which is getting perfect output for any channel??

http://in.mathworks.com/matlabcentral/fileexchange/38749-raptor-and-fountain-codes

Answer 1

[Walter Roberson]

According to Wireless Algorithms, Systems, and Applications: 6th International Conference, WASA 2011, Chengdu, China, August 11-13, 2011, Proceedings, page 386, heading "IR Cooperating with Raptor Codes", there is no perfect raptor code except possibly for Binary Erasure Channel.

Unless the author of that paper is wrong, your task of perfect codes "for any channel" is impossible.

Raptor codes are intended to asymptotically reach 100 percent probability of correct decoding as you increase the length. That is their purpose. That purpose would be meaningless if you could could achieve a "perfect" code, as a perfect code would have to have literal 100 percent probability of decoding within some finite length.