After getting past my initial assertion error, I've been reading the tutorials written by Dawei Shen trying to get a better understanding of the code that I'm dealing with. Granted the tutorials are a bit outdated, but between them and my existing programming knowledge I've been able to get through most of the tutorials. I'm now on the eigth of eleven total.
As I mentioned before, I'm trying to create my own working version of CSMA/CA protocol. However, so far, nothing has jumped out at me in the tutorials as being able to help me determine the SNR. I'm switching from my DSP book (Oppenheim, Schafer and Buck) to the tutorials to wikipedia articles in trying to get past this hump by myself, but in the meantime, could someone point me in the right direction? I'm expecting to see a measurement of decibels somewhere, but it's not happening in the tutorials.