PAPR and Sidelobe Reduction Using Tone Reservation in OFDM RadCom Systems

The orthogonal frequency-division multiplexing (OFDM) waveform in integrated radar and communication (RadCom) system has the problems of high peak-to-average power ratio (PAPR) and range sidelobe, which leads to the degradation of communication and sensing performance. In this article, the waveform optimization problem of jointly reducing PAPR and range sidelobe is formulated by using the tone reservation (TR) technique based on the degree of freedom provided by the frequency-domain reserved subcarriers. To solve this nonconvex optimization problem, the reserved subcarriers are divided into two parts to generate reduced PAPR and range sidelobe signals. The proposed scheme utilizes the least-squares approximation (LSA) method to reduce PAPR through partial reserved subcarriers, while the range sidelobe [integrated sidelobe level ratio (ISLR) or peak-to-sidelobe level ratio (PSLR)] within the coherent processing interval (CPI) is reduced by the remaining reserved subcarriers through the proposed two-step method. The numerical results show that the proposed scheme can allocate reserved subcarriers with different optimization objectives according to actual needs to obtain better PAPR or range sidelobe performance than existing schemes.