Оптимальні налаштування LORA-модему для супутникової радіолінії LEO з урахуванням доплерівських ефектів

Abstract

This paper addresses the selection of LoRa modem parameters for low‑Earth‑orbit (LEO) satellite links, where large Doppler frequency offsets and, more importantly, rapid Doppler variation can degrade packet reception. A practical engineering procedure is proposed to choose bandwidth and spreading factor under combined constraints: carrier frequency offset budget (Doppler and oscillator tolerance) and Doppler‑rate tolerance that depends on the receiver generation. For legacy SX12xx/SX1301‑class receivers the limiting factor is packet‑level drift over the time‑on‑air, which may create a near‑zenith ‘dead zone’, while LR11xx/SX1302‑class receivers show improved robustness due to symbol‑level tracking. The recommendations are validated using packet statistics collected from a community ground‑station network. The results provide parameter ranges and visibility windows that can be used for planning LEO LoRa downlinks and configuring gateways