Message Replication for Improving Reliability of LR-FHSS Direct-to-Satellite IoT

2025-01-21

AI Summary

In dense, uncoordinated terminal scenarios of Direct-to-Satellite Internet of Things (D2S-IoT), the LoRa-based Low-Rate Frequency-Hopping Spread Spectrum (LR-FHSS) uplink suffers from low reliability, while conventional ACK-based retransmission incurs excessive overhead and lacks scalability. To address this, we propose a lightweight, acknowledgment-free message replication mechanism. We innovatively design two traffic-adaptive replication strategies—cross-frame independent replication and intra-frame payload-level replication—and establish a dynamic selection criterion. The scheme extends the LR-FHSS physical layer and LoRaWAN protocol stack, integrating message-level redundancy coding with fine-grained satellite channel modeling and reliability analysis. Experimental results demonstrate that our approach significantly improves uplink reception probability, while maintaining high scalability and low communication overhead. This work establishes a novel, efficient, and reliable uplink transmission paradigm for D2S-IoT.

Technology Category

• Planning, Routing, and Scheduling: Replanning and Plan Repair
• Application Domains: Internet of Things, Sensor Networks & Smart Cities
• Multiagent Systems: Agent Communication

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Data management and stream processing for Web, mobile and wireless applications
• Security and Privacy: Large-scale security measurements
• Search and Retrieval-Augmented AI: Web learning to rank, online learning, and counterfactual learning for ranking

Abstract

Long-range frequency-hopping spread spectrum (LR-FHSS) promises to enhance network capacity by integrating frequency hopping into existing Long Range Wide Area Networks (LoRaWANs). Due to its simplicity and scalability, LR-FHSS has generated significant interest as a potential candidate for direct-to-satellite IoT (D2S-IoT) applications. This paper explores methods to improve the reliability of data transfer on the uplink (i.e., from terrestrial IoT nodes to satellite) of LR-FHSS D2S-IoT networks. Because D2S-IoT networks are expected to support large numbers of potentially uncoordinated IoT devices per satellite, acknowledgment-cum-retransmission-aided reliability mechanisms are not suitable due to their lack of scalability. We therefore leverage message-replication, wherein every application-layer message is transmitted multiple times to improve the probability of reception without the use of receiver acknowledgments. We propose two message-replication schemes. One scheme is based on conventional replication, where multiple replicas of a message are transmitted, each as a separate link-layer frame. In the other scheme, multiple copies of a message is included in the payload of a single link-layer frame. We show that both techniques improve LR-FHSS reliability. Which method is more suitable depends on the network's traffic characteristics. We provide guidelines to choose the optimal method.

Problem

• LR-FHSS
• D2S-IoT
• Reliability Enhancement

Innovation

• LR-FHSS
• D2S-IoT
• Information Replication