A New Index Modulation for LoRa

Long range (LoRa) is a widely adopted Internet of Things (IoT) technique, but its fatal limit is a low-data rate. In this letter, we propose a new index modulation for LoRa to increase the data rate, in which multiple quasi-orthogonal chirps modulated under different spreading factors (SFs) are concurrently transmitted, thereby leveraging the SF domain as a means to carry more information. Both the coherent and noncoherent detection algorithms for the proposed index modulation are also developed in efficient forms. Numerical results demonstrate that the proposed scheme notably outperforms the state-of-the-art techniques.

Automated summary

This letter proposes a new index modulation technique for LoRa to increase the data rate. It concurrently transmits multiple quasi-orthogonal chirps modulated under different spreading factors, utilizing the spreading factor domain to carry more information. The coherent and noncoherent detection algorithms for the proposed index modulation are also developed in efficient forms. Numerical results demonstrate the superiority of the proposed scheme over state-of-the-art techniques.