system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How does you cellphone know certain cell signals are for it and most others aren't?
gpt
This is really tough to ELI5. It is based on orthogonal waveforms. Basically orthogonal means if you multiply one waveform by an orthogonal waveform, you get zero. So your phone has a code. When that code is multiplied by every other signal out there, it results in zero. When that code is multiplied by your encoded signal though, it results in a data signal. Your phone signal is the only signal not orthogonal to the code.