LR-FHSS: Analytical Model of Channel Capacity and Header Redundancy Optimization

Long-Range Frequency Hopping Spread Spectrum (LR-FHSS) is a recent IoT transmission technology that aims at providing wide radio coverage and high data collection capacity, as a single gateway would be able to collect traffic from tens of thousands of devices. LR-FHSS typically targets satellite IoT services or wide-area coverage in the FCC region. To quantify its traffic collection capacity, we propose a detailed analytical model of LR-FHSS and also run extensive simulations. The outcome is that, first, the maximum utilization of the LR-FHSS network is significantly larger than previously reported, even when maxing out the effect of interference between transmissions on neighboring subchannels. Second, the model allows to readily derive the optimal number of LR-FHSS header replicas for obtaining the best goodput; this number is often larger than the limit found in the standard.