Frequency Offset Cancellation for IEEE802.15.4a Based Ranging

IEEE 802.15.4a is an amendment to 802.15.4 for an alternative PHY. The principal interest of IEEE 802.15.4a is in providing communications and high precision ranging / location capability. In this paper, we present the performance metrics for ranging schemes. The analysis based on the performance metrics characterizes the features of ranging schemes as follows. For the TWR scheme, due to its turn around time, the frequency offset results in significant ranging error. Since SDS-TWR takes more than two times bandwidth of that by TWR, which results in not only lower capacity, but also higher sensitivity to mobility than that of TWR. We cancel the ranging error from the frequency offset in a different way. We introduce a frequency ratio based TWR (R-TWR) scheme, which cancels the ranging error based on the ratio of the frequency on the originator side to the frequency on the responder side. We prove that the ranging accuracy of R-TWR scheme can reach the same order as that of SDS-TWR, while the capacity and sensitivity to mobility keep same as TWR scheme.