I have been researching indoor positiong. I have to do it with wifi only, nothing else. Cannot use Wifi-RTT, FTM (Fine time measurement) ie IEEE802.11mc, and I have already tried RSSI, I took have taken out rough positioning with it's help. But everywhere online I read, it's not a worthy road, it won't give much accuracy. I need accuracy of 10 cm.
RTT, TDOA, TOF etc, offers more accuracy, but I can't seem to find a way to exchange message with wifi router, and timestamp it with high accuracy, without delay. Most I could do was TCP/IP and UDP messages, highly in accurate.
Can someone tell me or let me know resource where I can find some guidance with technical implementation of this thing?