Performance improvement of OFDM-based forward scatter radar using golay codes

This paper investigates the impact of Peak-to-Average Power Ratio (PAPR) on the performance of a Forward Scatter Radar (FSR) based on Orthogonal Frequency Division Multiplexing (OFDM) waveforms. While high PAPR is a well-known issue in OFDM-based radar systems, it becomes especially critical in amplitude-sensitive systems like FSR, where the transmitted waveform should ideally maintain a constant modulus. Previous studies show that OFDM's fluctuating amplitude increases the interference background level in FSR outputs, thus degrading the detection performance. To tackle this issue, in this paper we show that transmitting a low-PAPR OFDM waveform can mitigate this effect, representing a promising solution for scenarios featuring cooperative transmitters. Particularly, we resort to a Golay-based OFDM waveform, where the transmitted codewords are constrained to Golay complementary sequences, ensuring a 3 dB PAPR upper bound. Synthetic data analyses demonstrate that, along with the obvious advantage of a higher average transmitted power level, a low-PAPR Golay-based OFDM waveform achieves lower background levels and further enhanced signal to interference ratio in FSR, thereby improving target detection with respect to a standard OFDM waveform.