A. Said et R. Palazzo, USING COMBINATORIAL OPTIMIZATION TO DESIGN GOOD UNIT-MEMORY CONVOLUTIONAL-CODES, IEEE transactions on information theory, 39(3), 1993, pp. 1100-1108
A new method to design good unit-memory convolutional codes is present
ed. It is based on the decomposition of the original problem into two
easier subproblems, which can be formulated as optimization problems a
nd solved by new efficient heuristic search algorithms. The efficacy o
f the new method is demonstrated by a table containing 33 new unit-mem
ory convolutional codes (n, k) with 5 less-than-or-equal-to k less-tha
n-or-equal-to 8, rates R = k/n between 1/4 and 7/9, and complete memor
y (M = k), as well as 12 new linear block codes. Most of the new codes
found have maximum free distance.