Spectral Leakage Suppression for DFT-Based OFDM via Adjacent Subcarriers Correlative Coding

In spectrum pooling applications, the spectral leakage of DFT-based OFDM systems should be divided into two parts, in-band-out-of-subband (IBOSB) leakage and out-of- band (OOB) radiation. A scheme is proposed to suppress the IBOSB leakage and redistribute OOB radiation through the frequency domain correlative coding with appropriate weighting. It introduces the correlation between adjacent subcarriers, and the DFT-based spectrum is reshaped through mutually cancelation of the sidelobes. The optimum weighting factor is given. Analysis and simulation show that the proposed scheme significantly suppresses IBOSB spectral leakage compared to conventional OFDM. At the same time, carrier-interference ratio (CIR) is increased and maximum likelihood sequence detection (MLSD) can mostly compensate the BER degradation caused by error propagation at the expense of a little computation complexity.