  Chirps spread spectrum (CSS) modulation is the heart of long-range (LoRa)
modulation used in the context of long-range wide area network (LoRaWAN) in
internet of things (IoT) scenarios. Despite being a proprietary technology
owned by Semtech Corp., LoRa modulation has drawn much attention from the
research and industry communities in recent years. However, to the best of our
knowledge, a comprehensive tutorial, investigating the CSS modulation in the
LoRaWAN application, is missing in the literature. Therefore, in the first part
of this paper, we provide a thorough analysis and tutorial of CSS modulation
modified by LoRa specifications, discussing various aspects such as signal
generation, detection, error performance, and spectral characteristics.
Moreover, a summary of key recent advances in the context of CSS modulation
applications in IoT networks is presented in the second part of this paper
under four main categories of transceiver configuration and design, data rate
improvement, interference modeling, and synchronization algorithms.

Signal Processing