In this paper, we propose a multi-level non-binary quasi-cyclic low density parity check (nb-qc-ldpc) coded modulation (CM) scheme to reduce the decoding complexity while maintaining and/or exceeding the super BER per...
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ISBN:
(数字)9781510627710
ISBN:
(纸本)9781510627710
In this paper, we propose a multi-level non-binary quasi-cyclic low density parity check (nb-qc-ldpc) coded modulation (CM) scheme to reduce the decoding complexity while maintaining and/or exceeding the super BER performance of the traditional nb-qc-ldpc CM scheme. Firstly, local optimal searching combined with the classical superposition construction is proposed to construct the required nb-qc-ldpc codes with possibly enlarged girth and less number of the shortest cycles. Secondly, by analyzing the changing trend of the BER performance and decoding complexity of the nb-qc-ldpc code defined over GF(Q) incident to Q. We find that the decoding complexity increases proportionally with the increase of Q, but the best BER performance usually corresponds to a smaller Q. Finally, by replacing the high-order nb-qc-ldpc code based CM scheme to the multi-level low-order nb-qc-ldpc code based CM scheme, the decoding complexity can be effectively reduced. Simulation results show that the designed two-level GF. (4)/GF (8) qc-ldpccode based 16QAM/64QAM CM system can perform almost the same or even better BER performance with/than the corresponding traditional GF(16) / GF (64) qc-ldpccode based 16QAM/64QAM CM system.
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