Brendan J. Frey and David J. C. MacKay 1998.
Trellis-constrained codes.
Proceedings of the 35th Allerton Conference on Communication, Control and Computing 1997, Champaign-Urbana, Illinois.
We introduce a class of iteratively decodable
trellis-constrained codes as a generalization
of turbocodes, low-density parity-check codes,
serially-concatenated convolutional codes, and product codes.
In a trellis-constrained code, multiple trellises interact to
define the allowed set of codewords. As a result of these
interactions, the minimum-complexity single trellis for the
code can have a state space that grows exponentially with
block length. However, as with turbocodes and low-density
parity-check codes, a decoder can approximate bit-wise
maximum a posteriori decoding by using the sum-product
algorithm on the factor graph that describes the code.
We present two new families of codes,
homogeneous trellis-constrained codes
and ring-connected trellis-constrained codes,
and give results that show these codes perform in the same regime
as do turbo-codes and low-density parity-check codes.
Compressed postscript,
uncompressed postscript.
Back to Brendan Frey's home page.