Repeat Accumulate Codes by David MacKay

Repeat-Accumulate[pdf]
Algo:-
1.Consider K source Bits s1s2s3....sk.
2.Repeat each bit three times,giving N=3K bits.
3.Permute these N bits using a random permutation giving u1u2....uN
4,Transmit the accumulated sum t1=u1,t2=u1+u2...........
5.That's it.

This simple coding schemes gets surprisingly close to the Shannon Limit!!!!