The Impact of ISM Interference on LoRa BER Performance

LoRa networks have been recently establishing themselves as front runners among evolving low power wide area networks (LP-WAN). One typical feature of LP-WAN is the dense deployment of IoT-enabled devices that span a diverse set of technologies while sharing the same unlicensed industrial, scientific and medical (ISM) radio bands. Accordingly, successful planning and design of LoRa networks must consider the inevitable impact of ISM interference on the BER performance of LoRa modulation. In this paper, we evaluate the BER performance of LoRa modulation when affected by different types of ISM interference. More specifically, we quantify the loss in the LoRa signal reception sensitivity as a function of the Signal-to-Interference (SIR) ratio. Moreover, we investigate the ability of narrowband interference suppression to improve the BER performance. It is demonstrated that narrowband interference suppression can in fact significantly improve the resilience of LoRa modulation. Nevertheless, it is also shown that there exists an SIR threshold beyond which the impact of narrowband interference becomes negligible such that the deployment of interference suppression mechanisms during LoRa signal reception should be avoided.