Generalization of floor lifting for QC-LDPC codes

The given paper presents a method for constructing a QC-LDPC code of shorter length by length adaption from a given QC-LDPC code of maximal length. The proposed method can be considered as a generalization of floor lifting. Making some offline calculation it is possible to construct a sequence of QC-LDPC codes with different circulant sizes generated from a single exponent matrix of QC-LDPC code which has the largest length. The only parameter stored in memory is a constant needed for scaling in the lifting procedure. Simulation results show that the proposed lifting method achieves around a 0.1 dB coding gain on short lengths over previous lifting approaches.