I'm trying to devise some type of simple communication protocol between a single interrogator device and several corresponding transponders. The idea is that the transponders will be in "Sleep Mode". The interrogator will periodically wake up the transponders in the area and the transponders will each transmit some data to the interrogator for collection.
I'm having trouble figuring out how to resolve the collision that occurs when two or more transponders transmit their data at the same time and thus, the reader receives some mixed up, incorrect data. Or, errors that may occur due to the noisy environment. I figured adding some type of checksum to the data packet would be useful in detecting errors. That way, the reader can check if what it received is correct or not.
The premise is that if the reader receives something and detects it has being incorrect, it can tell the transponder that sent it to resend it in hopes of receiving it error free. My problem is that I do not know how to make the reader able to tell the correct transponder to resend. How can I make this possible? Is there perhaps an easier way? I read about the different TDMA algorithms and ALOHA based schemes but they seem to be way out of my league. Any pointers or tips?
Thanks and I apologize if I may seem a bit vague but will further elaborate if need be.