In this approach, a Wi-Fi enabled router is being kept at
strategic locations inside the building. Whenever mobile terminal
sends a positioning request to any of these access point routers,
these routers will forward the position information to the server.
Server then aggregates and computes the information and send
computed position back to the mobile terminal. Furthermore, for
detecting direction of user’s device various methods like
Received signal strength (RSS), Angle of Arrival (AoA), Time of
Arrival (or Time of Flight), Time Difference of Arrival (TDoA)
etc. are used