A Backscatter Channel Sounder Using Tunneling RFID Tags

This paper introduces a backscatter channel sounder technique used for a radio-frequency identification (RFID) positioning system at 5.8 GHz. This system applies received signal phase (RSP)-based positioning and channel sounding techniques to a tunneling tag, providing sufficient information to calculate the delay spectrum for accurate positioning in a complicated multipath environment. Ultra-precise (0.45%) position estimates at long distances (100 m) are achieved using the proposed channel sounding techniques.