  Low power wide area network technologies (LPWANs) are attracting attention
because they fulfill the need for long range low power communication for the
Internet of Things. LoRa is one of the proprietary LPWAN physical layer (PHY)
technologies, which provides variable data-rate and long range by using chirp
spread spectrum modulation. This paper describes the basic LoRa PHY receiver
algorithms and studies their performance. The LoRa PHY is first introduced and
different demodulation schemes are proposed. The effect of carrier frequency
offset and sampling frequency offset are then modeled and corresponding
compensation methods are proposed. Finally, a software-defined radio
implementation for the LoRa transceiver is briefly presented.
