Investigation of Indoor LoRaWAN Signal Propagation for Real-World Applications

The advent of Internet of Things has resulted in new communication protocols such as LoRaWAN and Narrowband IoT slowly rising to be viable and even better alternatives to traditional protocols such as Wi-Fi and Bluetooth. LoRa in particular, has attracted a lot of attention owing to low power consumption of end nodes, low cost and use of license-free sub-GHz bands. Further, high link budgets in LoRaWAN communication allow for fewer gateways to provide network coverage over a large area. However, the success of deployment of LoRaWAN gateways in real world applications depends on meticulous planning. A major drawback in this scenario is the lack of extensive data on loss of signal strength, particularly in cityscapes, where buildings and trees can create significant path loss. In this paper, we investigate the path loss for LoRaWAN signals inside a typical city building (brick walls, reinforced cement concrete ceiling, wooden doors). The RSSI values of transmissions from multiple locations to a stationary gateway have been analysed to find the effect of indoor obstacles such as walls and doors on the propagation of LoRaWAN signals. We report that significant loss of energy can occur, even at relatively close range, because of the structures.