In this letter, we propose dual-mode chirp spread spectrum (DM-CSS) modulation for low-power wide-area networks. DM-CSS is capable of achieving a higher spectral efficiency (SE) relative to its counterparts, such as Long Range (LoRa) modulation. Considering the same symbol period, SE in are augmented by: (i) simultaneously multiplexing even and odd signals; (ii) using phase shifts 0 <inline-for...
