LDPC-Coded Spectrally Efficient FDM System with Iterative Decoder

In this paper, low-density parity-check (LDPC) codes are applied in spectrally efficient frequency-division multiplexing (SEFDM) with iterative decoder to eliminate the influence from inter-carrier interference (ICI). SEFDM has higher spectral efficiency than orthogonal frequency-division multiplexing (OFDM) by compressing the subcarrier spacing. This self-induced ICI is eliminated by LDPC codes and iterative decoder. The SEFDM scheme analyzed in this paper is not limited by subcarrier number and modulation order because the ICI cancellation scheme has relatively low computational complexity. With LDPC codes, the iterative-SEFDM scheme supports QPSK, 16QAM, 64QAM and 256QAM modulation formats. To the best of our knowledge, the SEFDM scheme with high-order 256QAM modulation is first demonstrated. With bandwidth compression and effective ICI cancellation, LDPC-coded iterative-SEFDM can achieve better bit error rate performance than its counterpart LDPC-coded OFDM at the same spectral efficiency.