Radio localization in OFDM networks using the “round trip phase”

In this paper, we present a localization technique for wireless nodes using OFDM modulation. It enables a wireless transceiver to calculate the distance to a second transceiver by measuring the round trip time of flight at the physical layer. The method was first modeled and simulated in MatLab for a 5 GHz according to the IEEE 802.11a standard and a 60 GHz wireless OFDM network with 400 MHz bandwidth. The simulation shows an accuracy of about 2 - 4 m mean absolute error in the 5 GHz network and 10 - 30 cm mean absolute error in the 60 GHz network. A demonstrator for the 5 GHz network was implemented on an FPGA board with a wireless front end. The achieved accuracy is up to submeter range.