I would like to kindly inform you however that we volunteers who work for a living are not here to bypass your learning by gift wrapping answers and feeding them to you on demand. Particularly when you display such poor analytical skills and jump to conclusions. Conclusions like the heap vs stack, it’s the gateway, it’s the board speed, versions of the stack regardless of specification compliance etc etc.
Give a man a fish and he will need one everyday. Teach a man to fish and he can get his own fish when he needs them.
So we are absolutely definitely not doing your homework for you because your job is to do your own homework. Except in so many cases we already have if you do proper prior research: GitHub - descartes/Arduino-LMIC-example: Known good Arduino ATmega328 + LoRa chip LoRaWAN node excepting that we’ve moved on to the almost no-brainer to implement with the right hardware: GitHub - lnlp/LMIC-node: LMIC-node | One example to rule them all. LMIC-node is an example LoRaWAN application for a node that can be used with The Things Network. It demonstrates how to send uplink messages, how to receive downlink messages, how to implement a downlink command and it provides useful status information. With LMIC-node it is easy to get a working node quickly up and running. LMIC-node supports many popular (LoRa) development boards out of the box. It uses the Arduino framework, the LMIC LoRaWAN library and PlatformIO. - referred to a lot on the forum and with a name like it comes up in the forum search oooooo so easily.
And if you took the time to explore your library of choice, you’d find a whole set of options, settings & configs - particularly those in config.h - to remove various items you may not need.
And then, with some insightful questions demonstrating prior research, including the frequently repeated refrain of “to develop a device you need access to a gateway console, preferably one you own”, you’d probably have got the response of: GitHub - ngraziano/LMICPP-Arduino: Lmic (LoraWAN-in-C) modified to C++ - which has tight boundaries on hardware due to the use of a port of STL, but compiles at 17KB for a Pro Mini leaving lots of room for sensors.
With a user name of descartes, what do you expect. It’s the only pleasure I have in life and by making your brain work, you are more likely to learn how to turn it on by yourself!