ESP32_LoRaWAN-Lib wake from sleep CLASS_C

Since this forum recommended to use the Heltec/ ESP32_LoRaWAN - Library I tried some stuff with teh example pingpong.ino .

If I adapt the pingpong.ino for my purpose, that I send a packet if e.g. a serial interrupt occurs and otherwise be ready to receive it just works if I never go to sleep (I created an IDLE State after STATE_RX). How do I manage to wake up the LoRa if I’m in STATE_SLEEP (CLASS_C) on packet receive or interrupt it or something link that?

Thanks in advance