METHOD FOR FRAME SYNCHRONIZATION OF BLOCK LOW-DENSITY CODES Russian patent published in 2024 - IPC H04L7/08 

FIELD: physics.

SUBSTANCE: invention relates to a method for frame synchronization when receiving transmissions using systematic linear block low-density codes of long length. Input discrete sequence of symbols of codewords of length n is received using a receiver of discrete information, extraction from each codeword of length n fragments of length n'=n⋅R+4 with interval t=n-n'. Then, 2⋅n' successively selected from the obtained discrete sequence of fragments of length 2⋅n' writing in matrix rows, by elementary transformations of rows the formed matrix is reduced to canonical stepped form, by permutation of rows, a matrix is obtained, in which the first nonzero element of each nonzero row is equal to one, is located on the main diagonal and is the only nonzero element of its column; the correspondence of the obtained matrix is used as a sign of the synchronous state of the receiver of discrete information. After detecting this feature, it is considered that the synchronous state has been achieved, and in the absence of the synchronous state feature, the received sequence is successively shifted by one symbol to the same side, fragments of length n' with interval t and re-analysing the state of the receiver on the basis of the synchronous state. After identifying the sign of the synchronous state, it is considered that the synchronous state has been achieved.

EFFECT: reducing the amount of sampling symbols of the received discrete sequence required for code frame synchronization.

1 cl, 9 dwg, 1 tbl