Cross-technology interference between lora 2.4 GHZ and WIFI: simulations and experiments

Abstract

Semtech recently extended the LoRa physical layer to the 2.4 GHz ISM band, gaining global spectrum availability at the cost of sharing the band with WiFi. A WiFi transmission occupies 20 MHz and can arrive 25–40 dB stronger than the overlapping LoRa signal. No packet-level characterization across the full LoRa 2.4 GHz parameter space under controlled WiFi interference existed prior to this work. This thesis investigates LoRa-WiFi coexistence at 2.4 GHz through experiments and simulation. Packet Reception Ratio (PRR) was measured on ESP32-based devices with SX1280 transceivers under IEEE 802.11n interference across all eight spreading factors (SF 5–12), four coding rates, and five distances (5 cm to 3 m). An ns-3 module was developed for LoRa 2.4 GHz, integrated with the existing WiFi model through the SpectrumChannel framework. At 0.5 m from the WiFi source, SFs above 9 still delivered PRR above 0.8, and switching the coding rate from 4/5 to 4/8 brought back up to 23% of packets that would otherwise be lost. When compared to the experimental data, the simulation stayed within 5 percentage points for distances of 0.5 m and beyond. Three scenarios extend the analysis: scaling to 10 WiFi sources, varying traffic load, and sweeping model parameters. SF12 holds PRR at 1.0 regardless of WiFi density; SF5 drops below 0.5 with five nearby access points.