Spectral Efficiency Improvement of Chirp Spread Spectrum Systems

The chirp spread spectrum (CSS) systems use various chirp signals for spreading the transmission bandwidth. Although spreading the transmission bandwidth can improve the transmission performance in jamming and fading environments, the CSS systems should also consider spectral efficiency. Thus, in this paper, we propose a spectral efficiency improvement scheme for the CSS systems. The proposed scheme divides the chirp duration equally and allows overlapping of the chirps to transmit more bits. Simulation results show that the proposed scheme can significantly improve the spectral efficiency of the CSS systems.