On the Gray Indexing in LoRa PHY

Abstract

Long range wide area network (LoRaWAN) is one of the most widely used low power wide area (LPWA) network technologies operating in the unlicensed ISM band. Its physical layer (that is, LoRa PHY) which is Semtech's proprietary technology uses Gray indexing in LoRa symbol mapping. In this paper, we will investigate the effect of Gray indexing to the performance of LoRa PHY. Specifically, through computer simulations, we will compare FER performances according to with and without Gray indexing in AWGN and Rician fading environments.