I have a course challenge. It involves calculating an FFT of an audio signal of 2 combined frequencies (up to 20KHz) then sending it over LoRa through to a fixed receiver. There will be an interferer. Spreading factor is fixed. Grading is based on power consumed by the transmitter and time between start of calculation and receiving an acknowledgement from the receiver. The exact degree of each grading is not unknown.
We may modify any parameters, such as antenna, baud / bitrate, etc, FFT calculation, compression.
I have a strategy for compressing the values in single bits. Is this possible:
The receiver will receive a bit to start counting, and at that point, it will start counting on its internal clock. Once the transmitters internal clock = x * 100 nanoseconds, where x refers to the value being sent and 100 nanoseconds is the likely accuracy of a GPS signal, it will send a 1 bit. The receiver, having felt x * 100 nanoseconds delay, will decode this message as having the value x.
The benefit will be sending 1 bit vs 16 bits of information will use less power on the radio module, but the waiting could be a penalty for time and static / dynamic waste due to leakage + counting nanoseconds on the accumulator.
I recognize LoRa had a minimum required packet size, but given a required spreading factor of 7 and likely redundancy to deal with an interferer, is this a worthwhile scheme?
Note: The transmitter and receiver are two copies of the same hardware microcontroller.