BIC-LoRa: Bits in Chirp Shapes to Boost Throughput in LoRa

LoRa is a low-power long-range radio technology for wide-area IoT connectivity with exceptional receiver sensitivity thanks to its chirp spread spectrum (CSS) modulation. However, insufficient data rate has always been an Achilles’ heel of LoRa. This paper proposes a novel PHY-layer design, BIC-LoRa, that leverages non-linear chirp shapes as pictograph to enhance LoRa’s data rate. It employs multiple non-linear chirps for modulation whose shapes encode additional bits to boost data rate while maintaining resilience to low SINR scenarios. To the best of our knowledge, this is the first attempt to enhance the data rate of LoRa by embedding bits in the chirp shapes. Furthermore, BIC-LoRa fully leverages the characteristics of non-linear chirps, allowing it to deal with packet collisions and increase network throughput. We implement BIC-LoRa in GNURadio and MATLAB, and compare its performance against CurveALOHA and standard LoRaWAN through real experiments on USRP B210 software-defined radios. Evaluation results demonstrate that BICLoRa achieves up to 29.4% improvement in data rate for a single link and 32% improvement in overall network throughput while retaining the low SNR robustness of LoRa in real-world scenarios.