A Multi-carrier Modulation System Suitable for Fragmented Spectrum Reuse

The future applications of mobile communication require lower out-of-band (OOB) radiation and higher spectral efficiency. The widely used orthogonal frequency division multiplexing (OFDM) system suffers from severe OOB radiation, sensitivity to timing and frequency offsets, and the requirement for uniform waveform parameters across the entire frequency band. To adapt to the flexible and diverse nature of new application scenarios in mobile communication, a filtering multi-carrier modulation system based on time-frequency blocks is proposed. This system allows flexible adjustment of the occupied time-frequency block size according to the characteristics of the desired services, thereby controlling the peak-to-average power ratio (PAPR) and transmission delay of the system. Moreover, the introduced filter effectively suppresses sub-band spectrum leakage. Compared to the OFDM system, simulation results in additive white Gaussian noise channels and Rayleigh fading channels show that the proposed multi-carrier system exhibits better OOB radiation and PAPR, while achieving comparable bit error rate (BER) performance.