Back to results
US 12,750,759 B2Granted
Determing time of arrival based on phase measurement
AssigneeNokia Technologies Oy
InventorsDaejung Yoon, Jorge Morte Palacios, Satya Krishna Joshi
Life of this patent
Estimating the term…
Abstract
A method can include determining that a received signal traveled via a shortest path from a transmitting device to a receiving device of an orthogonal frequency-divisional multiplexing (OFDM) communication system, determining a phase rotation of the received signal, and determining a time of arrival based on the determined phase rotation.
Claims20
An apparatus comprising:
- a processor;
- and
- a memory comprising computer executable instructions that, when executed by the processor, cause the apparatus to perform the following operations:
- obtaining raw channel estimates in a frequency domain for a received positioning reference signal transmitted in an orthogonal frequency-division multiplexing (OFDM) system;
- determining that the received positioning reference signal traveled via a shortest path by performing a channel flatness test in the frequency domain, wherein the channel flatness test comprises counting a number of peaks or amplitude ranges of the raw channel estimates that exceed a channel threshold, and determining that the received positioning reference signal corresponds to the shortest path when the counted number is less than a flatness threshold;
- selecting the received positioning reference signal as a flat channel based on the channel flatness test;
- determining a phase rotation of the flat channel by computing an autocorrelation of the raw channel estimates across multiple frequency separations and deriving a frequency-domain phase rotation from the autocorrelation;
- and
- determining a time of arrival of the received positioning reference signal by dividing the determined phase rotation by a subcarrier spacing of the OFDM system.
6 more elements
A method performed by an apparatus, the method comprising:
- obtaining raw channel estimates in a frequency domain for a received positioning reference signal transmitted in an orthogonal frequency-division multiplexing (OFDM) system;
- determining that the received positioning reference signal traveled via a shortest path by performing a channel flatness test in the frequency domain, wherein the channel flatness test comprises counting a number of peaks or amplitude ranges of the raw channel estimates that exceed a channel threshold, and determining that the received positioning reference signal corresponds to the shortest path when the counted number is less than a flatness threshold;
- selecting the received positioning reference signal as a flat channel based on the channel flatness test;
- determining a phase rotation of the flat channel by computing an autocorrelation of the raw channel estimates across multiple frequency separations and deriving a frequency-domain phase rotation from the autocorrelation;
- and
- determining a time of arrival of the received positioning reference signal by dividing the determined phase rotation by a subcarrier spacing of the OFDM system.
3 more elements
Dependencies are inferred from the claim text.