Implementation of PLIM on 429MHz LoRa/FSK with improved conversion table

LPWA (Low Power Wide Area) is a communication method for the IoT that enables long-distance communication with low power consumption, and PLIM (Packet Level Index Modulation), an extension of LPWA, enables several bits of additional transmission. However, there is a problem of data loss due to packet collision when transmitting simultaneously and on the same frequency channel. The authors have implemented PLIM on a 429 MHz LoRa/FSK and improved the collision rate by randomly creating and assigning mappings in the implementation. In this paper, the authors conducted experiments on a real device using a method of designing optimal mappings using mathematical optimization, showed the effectiveness of the method and how it differs from other mappings, and evaluated the method in a real device environment.