S.V. Ovsyankin – Ph.D. (Eng.), Staff Member, Academy of Federal Security Guard Service (Oryol))
A.A. Proskurin – Ph.D. (Eng.), Staff Member, Academy of Federal Security Guard Service (Oryol)
I.N. Molchanov – Ph.D. (Eng.), Staff Member, Academy of Federal Security Guard Service (Oryol)
V.O. Yudin – Staff Member, Academy of Federal Security Guard Service (Oryol)
E-mail: interleaver@mail.ru

The paper is dedicated to the LDPC encoding evolution applied to the satellite systems and optical transport networks. The questions of the additional to the existing optical transport units FEC usage (SD-FEC) are touched. The reasons of LDPC codes usage as SD-FEC (LDPC codes were applied heretofore as HD-FEC, G.975.1 I.6) and the transition from a binary alphabet to symbols of the Galois field extensions are viewed. The analisys of the code structure influence on the decoding result in the variable cases is present. The process of an non-binary LDPC code construction is given by example.

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