PCube: Scaling LoRa Concurrent Transmissions with Reception Diversities

• Published in: ACM transactions on sensor networks 2023-03, Vol.18 (4), p.1-25, Article 66
• Main Authors: Xia, Xianjin, Hou, Ningning, Zheng, Yuanqing, Gu, Tao
• Format: Article
• Language: English
• Subjects: Computer systems organization; Embedded systems; Link-layer protocols; Network protocol design; Networks
• ISSN: 1550-4859; 1550-4867
• DOI: 10.1145/3545571

This article presents the design and implementation of PCube, a phase-based parallel packet decoder for concurrent transmissions of LoRa nodes. The key enabling technology behind PCube is a novel air-channel phase measurement technique that is able to extract phase differences of air-channels between LoRa nodes and multiple antennas of a gateway. PCube leverages the reception diversities of multiple receiving antennas of a gateway and scales the concurrent transmissions of a large number of LoRa nodes, even exceeding the number of receiving antennas at a gateway. As a phase-based parallel decoder, PCube provides a new dimension to resolve collisions and supports more concurrent transmissions by complementing time and frequency-based parallel decoders. PCube is implemented and evaluated with synchronized software defined radios and off-the-shelf LoRa nodes in both indoors and outdoors. Results demonstrate that PCube can substantially outperform state-of-the-art works in terms of aggregated throughput by 4.9× and the number of concurrent nodes by up to 5×. More importantly, PCube scales well with the number of receiving antennas of a gateway, which is promising to break the barrier of concurrent transmissions.