LTE and LoRa in the 2.4 GHz Band: Adjacent Channel Interference Issues

In 2017, the Semtech company has released the SX1281 transceiver with the aim to provide Long-Range (LoRa) wireless data link in the 2.4 GHz Industrial, Scientific and Medical (ISM) radio frequency (RF) band. In the future, massive utilization of a LoRa-based technology can cause an origin of new unwanted coexistence scenarios in this license-free RF band. This paper focuses on the adjacent channel interference issues that can occur between Long Term Evolution (LTE) and LoRa systems in the 2.4 GHz band. The influence of LoRa signal on the LTE one is explored on physical (PHY) layer level. An automated laboratory measurement setup is employed to measure and calculate protection ratio for different LTE system configurations. Results show that LoRa with different system parameters influences the performance of LTE in different way.