Abstract: Some embodiments are directed to a method for controlling a check node of a NB-LDPC decoder. The check node receives dc input lists Ui and delivers and delivers dc output lists Vi, with i?[1 . . . dc]. Each input list and output list includes nm elements and each element of the input or output lists includes a reliability value associated to a symbol of a Galois Field GF(q) with q>nm. The input elements and output elements are sorted according to the reliability values in the lists. The method is a syndrome-based method. The syndromes are sums of dc elements of input lists Ui. The method includes a step of syndrome calculation, a step of decorrelation and a step for generating the output list.