Estimating and using characteristic differences between wireless signals

Patent metadata

Field	Value
Publication number	US-12015452-B2
Application number	US-201917310726-A
Country	US
Kind code	B2
Filing date	Feb 21, 2019
Priority date	Feb 21, 2019
Publication date	Jun 18, 2024
Grant date	Jun 18, 2024

Abstract

A method and apparatus are provided for estimating characteristic differences between wireless signals transmitted from the same location in spaced apart frequency ranges. Also provided are a method and apparatus for estimating a combined time of arrival of the wireless signals, using the characteristic differences. A further method is provided, for identifying that two signals have been transmitted from the same location. Also disclosed is a method of maintaining a database of characteristic difference information.

First claim

The invention claimed is:

1. A method of estimating one or more characteristic differences between two wireless signals, the method comprising:
receiving a first wireless signal transmitted in a first frequency range;
receiving a second wireless signal transmitted in a second frequency range, wherein the second frequency range is spaced from the first frequency range, and wherein the second wireless signal is transmitted from the same location as the first wireless signal;
processing the first wireless signal and the second wireless signal to estimate the one or more characteristic differences between them, the one or more characteristic differences comprising at least one or any combination of two or more of:
a relative offset in their time of transmission;
a relative carrier phase relationship between them; and
a relative amplitude relationship between them; and
estimating a combined time of arrival for the first wireless signal and the second wireless signal, wherein estimating the combined time of arrival is based on the first wireless signal, the second wireless signal, and the one or more characteristic differences, and wherein estimating the combined time of arrival comprises:
aligning a first channel impulse response and a second channel impulse response, based on the one or more characteristic differences, to generate aligned channel impulse responses;
combining the aligned channel impulse responses to generate a combined channel impulse response; and
estimating the combined time of arrival from the combined channel impulse response.

2. The method of claim 1 , wherein processing the first wireless signal and the second wireless signal to estimate the one or more characteristic differences comprises:
processing the first wireless signal to estimate the first channel impulse response;
processing the second wireless signal to estimate the second channel impulse response; and
comparing the first channel impulse response with the second channel impulse response to estimate the one or more characteristic differences.

3. The method of claim 2 , wherein comparing the first channel impulse response with the second channel impulse response comprises calculating a cross-correlation function between the first channel impulse response and the second channel impulse response.

4. The method of claim 2 , further comprising identifying one or more first multipath components in the first channel impulse response and identifying one or more second multipath components in the second channel impulse response,
wherein the one or more characteristic differences are estimated based on the identified the one or more first multipath components and the one or more second multipath components, or the one or more characteristic differences are estimated jointly with the identifying of the one or more first multipath components and the one or more second multipath components.

5. The method of claim 1 , wherein a transmitter of at least one of the first and second wireless signals has a plurality of different transmission modes, the method further comprising estimating the one or more characteristic differences between the first and second wireless signals for each respective transmission mode.

6. The method of claim 1 ,
wherein estimating the combined time of arrival is done jointly with processing the first wireless signal and the second wireless signal to estimate the one or more characteristic differences.

7. The method of claim 4 , further wherein estimating the combined time of arrival for the first wireless signal and the second wireless signal is based on:
the one or more first multipath components; and
the one or more second multipath components.

8. The method of claim 4 ,
wherein estimating the combined time of arrival is done jointly based on at least one of:
(i) processing the first wireless signal and the second wireless signal to estimate the one or more characteristic differences, or
(ii) identifying the one or more first multipath components and the one or more second multipath components.

9. The method of claim 7 , further comprising:
identifying a first line-of-sight component from among the one or more first multipath components; and
identifying a second line-of-sight component from among the one or more second multipath components,
wherein the combined time of arrival is estimated based on the first and second line of sight components.

10. The method of claim 7 , wherein estimating the combined time of arrival further comprises:
aligning the one or more first multipath components and the one or more second multipath components, based on the one or more characteristic differences, to generate an aligned set of multipath components; and
estimating the combined time of arrival from the aligned set of multipath components.

11. The method of claim 1 , further comprising estimating a rate of change of at least one of the one or more characteristic differences.

12. The method of claim 11 , further comprising generating a model for predicting a value of the at least one of the one or more characteristic differences at other times.

13. A method of identifying that a first wireless signal and a second wireless signal were transmitted from the same location, the method comprising:
receiving, at a first location, a first wireless signal and a second wireless signal, thereby producing first received signals;
receiving, at a second location, the first wireless signal and the second wireless signal, thereby producing second received signals;
processing the first received signals to estimate one or more first characteristic differences between them;
processing the second received signals to estimate one or more second characteristic differences between them;
comparing the one or more first characteristic differences with the one or more second characteristic differences to determine whether they match; and
in response to a determination that the one or more first characteristic differences match with the one or more second characteristic differences, determining that the first and second wireless signals were transmitted from the same location,
wherein the first wireless signal is transmitted in a first frequency range and the second wireless signal is transmitted in a second frequency range, spaced from the first frequency range, and
wherein at least one of the one or more first characteristic differences or the one or more second characteristic differences comprise at least one or any combination of two or more of:
a time offset;
a carrier phase relationship; and
an amplitude relationship,
wherein at least one of processing the first received signals or processing the second received signals further comprises:
estimating a combined time of arrival for the first wireless signal and the second wireless signal, wherein estimating the combined time of arrival is based on the first wireless signal, the second wireless signal, the one or more first characteristic differences, or the one or more second characteristic differences, and wherein estimating the combined time of arrival comprises:
aligning a first channel impulse response and a second channel impulse response, based on the one or more first characteristic differences or the one or more second characteristic differences, to generate aligned channel impulse responses;
combining the aligned channel impulse responses to generate a combined channel impulse response; and
estimating the combined time of arrival from the combined channel impulse response.

14. A method of maintaining a database of characteristic difference information associated wit

Assignees

• Ublox Ag

Inventors

• Marshall Christopher
• Biason Alessandro
• Driusso Marco
• Noschese Matteo
• Babich Fulvio
• Pin Alessandro
• Rinaldo Roberto

Classifications

• H04L25/0204 Primary

  of multiple channels · CPC title

• G01S5/02523

  Details of interaction of receiver with radio-map · CPC title

• G01S5/0218

  Multipath in signal reception · CPC title

• G01S11/02

  using radio waves (G01S19/00 takes precedence) · CPC title

• G01S5/0236

  Assistance data, e.g. base station almanac · CPC title