LR-FHSS with Network-Coded Header Replication

Long-Range Frequency-Hopping Spread Spectrum (LR-FHSS) has been recently introduced in the scope of Long Range Wide Area Network (LoRaWAN), aiming at alleviating packet collisions and increasing the network capacity. Such accomplishment is achieved by replicating the header and fragmenting each data packet into smaller segments while distributing them randomly across multiple channels, enhancing the robustness against interference. In the scope of LR-FHSS, recent works have suggested that the error rate of the headers are in fact dominant in the overall error rate of the system. Moreover, it is well-known that repetition codes are not optimal in terms of error correction capability. In this work, rather than simply replicating the headers, we propose the use of a network-coded-aided inter-header combination scheme, aiming at increasing the header protection against both erasures and collisions. We show through analytical and simulation results that the proposed scheme can considerably reduce the packet error rate by more than one order of magnitude under several scenarios.