Spectrally Efficient Communication System Based on Combined Chirp in Low SNR Environment

Chirp signal emerges as a promising technique for wireless communication systems in next-generation networks, owing to its better multipath diversity exploitation. However, due to the scarcity of radio spectrum resources, continuously increasing the bandwidth reduces spectral efficiency, imposing significant challenges to communication systems. In this paper, we design a high spectral efficiency transmission system based on the combination of chirp signals with different slopes, incorporating both up-chirp and down-chirp signals. To enhance system reliability, the linear equation-solving algorithm is innovatively combined with matched filtering. We further leverage oversampling to enhance system detection performance under low signal-to-noise ratio (SNR) conditions and rigorously derive the gain expressions. Extensive simulations demonstrate the effectiveness of the proposed method in terms of bit error rate (BER) performance and spectral efficiency in low SNR environment.