LoRa-like CSS-based PHY layer, Capture Effect and Serial Interference Cancellation

Abstract:
Long Range communications are taking an important place in the IoT world. One Physical Layer solution is LoRa. It is based on Chrip Spread Spectrum. In this paper, we review how this modulation technique carries information. However, a simple MAC layer, like ALOHA, will rapidly limit the capacity (in term of number of users) of such networks. However, sensing the channel will not resolve the collision problem because of the very wide coverage of access points. We study how capture effect and even more serial interference cancellation can drastically improve the performance. The position randomness of transmitters can allow to correctly decode simultaneous transmissions.