Method and device for estimating a time of arrival of a radio signal

Patent metadata

Field	Value
Publication number	US-11428774-B2
Application number	US-201916659891-A
Country	US
Kind code	B2
Filing date	Oct 22, 2019
Priority date	May 10, 2017
Publication date	Aug 30, 2022
Grant date	Aug 30, 2022

Abstract

A method and device for estimating the time of arrival (ToA) of a radio signal are proposed. The radio signal comprises M subsignals carried on M subcarriers, where M is an integer ≥2. The number of propagation paths and the time of arrival associated with a first path are estimated. The technique can improve ToA estimation accuracy, especially in a multipath fading channel, and reduce the need for channel information.

First claim

What is claimed is:

1. A method for estimating a time of arrival of a radio signal at a wireless communication device, wherein the radio signal comprises M subcarriers, wherein M≥2, and wherein the method comprises:
receiving the radio signal by the wireless communication device;
obtaining, by the wireless communication device, M subsignals from the M subcarriers, by demodulating each of the M subcarriers to obtain a respective one of the M subsignals;
determining an autocorrelation matrix P of the M sub signals;
estimating a number of propagation paths based on the eigenvalues and eigenvectors of the autocorrelation matrix; and
estimating a time of arrival of the radio signal associated with a first path based on the eigenvalues and eigenvectors of the autocorrelation matrix and the estimated number of propagation paths.

2. The method according to claim 1 , wherein the determining of the autocorrelation matrix P comprises:
normalizing the subsignals, and calculating the autocorrelation matrix based on the normalized subsignals.

3. The method according to claim 1 , wherein the estimating of the number of propagation paths comprises finding an integer value m∈{1, 2, . . . , N P } that minimizes the function

MDL
⁡

(
m
)

=

-

(

N
p

-
m

)

⁢
L
⁢

⁢

log
(

∏

i
=

m
+
1

N
p

⁢

λ
i

1

N
p

-
m

1

N
p

-
m

⁢

∑

i
=

m
+
1

N
p

⁢

λ
i

)

+

1
2

⁢

m
⁡

(

2
⁢

N
P

-
m

)

⁢
log
⁢

⁢
L

,

wherein N P ∈{2, 3, . . . , M} is an upper boundary of the multipath searching range {1, 2, . . . , N P }; and λ i are eigenvalues of autocorrelation matrix P.

4. The method according to claim 3 , wherein the estimating of the time of arrival associated with the first path comprises evaluating Q(t) as follows:

Q
⁡

(
t
)

=

1

ϕ
H

⁡

(
t
)

⁢

GG
H

⁢

ϕ
⁡

(
t
)

,

wherein t is the time of arrival of the first path corresponding to a maximum of Q(t), and 0≤t≤N w ; where N w is a searching window size.

5. The method according to claim 1 , further comprising generating M symbol sequences by extracting, from each of the M subsignals, L consecutive symbols, the L extracted consecutive symbols forming a respective one of the M symbol sequences.

6. The method according to claim 5 , wherein the determining of the autocorrelation matrix P comprises calculating the autocorrelation matrix P based on the M symbol sequences.

7. The method according to claim 5 , wherein the determining of the autocorrelation matrix P comprises calculating P as follows:

Assignees

• Huawei Tech Co Ltd

Inventors

• Xue Jiantao
• Gao Yuan
• Han Jing
• Dai Xizeng

Classifications

• G01S11/02 Primary

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

• G01S5/0244 Primary

  Accuracy or reliability of position solution or of measurements contributing thereto · CPC title

• G01S5/0218

  Multipath in signal reception · CPC title

• G01S5/0273 Primary

  using multipath or indirect path propagation signals in position determination · CPC title

• G01S3/00

  Direction-finders for determining the direction from which infrasonic, sonic, ultrasonic or electromagnetic waves, or particle emission, not having a directional significance, are being received (position-fixing by co-ordinating a plurality of determinations of direction or position lines G01S5/00) · CPC title