Order of functions to transmit and receive using layer1

I was wondering how to transmit and receive using layer1. I have been reading some of the gsm specs. I have been looking around in the source code a lot, and there many functions that are used for transmit and receive. Which are the right few to use? Is there any way to send a text message to a different phone by simulating a base station? Do I need two phones or one phone to transmit and receive as a base station? Is there any way to make a half duplex base station on a BCCH channel with only one subscriber phone at a time, and what would that entail code-wise? Would it be legal to run a very low power base station in the USA on a different unused cellular band/frequency? I have a lot of free time since I do school at home and I could probably help develop some new parts of the osmocom-bb project if you want me to. I know C, some x86 assembly, and a few other languages. I have also had practice fixing compile-time errors, and bugs in code. I apologize if this is too many questions. You don't have to answer them all if you don't want to. Thank you for helping, Calvin E. Balke