Devices, systems and methods for reducing complexity of a bit-flipping decoder for quasi-cyclic (QC) low-density parity-check (LDPC) codes are described. An example method includes receiving a noisy codeword that is based on a transmitted codeword generated from an irregular QC-LDPC code, the irregular QC-LDPC code having an associated parity matrix, storing, based on a weight of a plurality of columns of the parity matrix of the irregular QC-LDPC code, a portion of the noisy codeword corresponding to the plurality of columns in a first buffer of a plurality of buffers, and accessing and processing the portion of the noisy codeword that includes applying a vertically shuffled scheduling (VSS) scheme that uses a plurality of processing units to determine a candidate version of a portion of the transmitted codeword that corresponds to the portion of the noisy codeword.