Radar communication integrated signal design and processing methods based on amplitude coded modulation

To address the challenges of high bit error rate (BER) and false target peaks in high-resolution range profile (HRRP) within dual-functional radar-communication (DFRC) systems, this study proposes innovative processing methods for linear frequency modulation (LFM) waveform modulated by amplitude codes, alternatively referred to as LFM-ASK waveform. The characteristics of the LFM-ASK waveform are investigated. For communication function, a reference signal is constructed based on the segment summation of the LFM signal, and the amplitude codes are recovered by sampling the reference signal's matched filter output at each code beginning and applying a threshold-based decision. For radar function, a pair of complement codes is employed to generate two LFM-ASK signals. The same order false target peaks in the two HRRPs of the echoes have opposite phases, and the false targets can be effectively eliminated by summing the two HRRPs. Comprehensive simulations and experiments have been conducted, demonstrating the effectiveness of the proposed processing methods. The results indicate that the proposed demodulation method decreases the BER by 36 % and 16 % compared to envelope demodulation and coherent demodulation at 0 dB signal-to-noise ratio (SNR). Additionally, the proposed elimination method not only suppresses signal-induced false targets but also reduces the number of noise-induced false targets from over 3 to 0 compared to the compressive sensing method.