What generally available bi-directional wireless communication technologies are available in the smallest footprints? I'm working on a project where multiple devices need to communicate with each other, but I need to do so in the smallest footprint possible. Communication doesn't have to be sophisticated as it will be mostly sending relative coordinates to neighboring devices and distances can be pretty small - but I'd super happy with 10cm between devices. NFC? Bluetooth? Wi-Fi is out because all the full stack implementations are huge. I'm thinking an NFC transponder. The devices will be powered so I don't have to worry about a passive power antenna. Is NFC the simplest/smallest footprint wireless communication technology generally available? Something else I should be looking at?
General requirements:
- ~10cm distance between devices but the further the better
Prefer a single-chip solution
Bi-directional communication
Faster transmission speed is better
Short connection setup time preferred, but a longer setup time can be tolerated if sessions are maintained (like bluetooth)