Radio station for client localization in multipath indoor environment

Patent metadata

Field	Value
Publication number	US-11754658-B2
Application number	US-202217651856-A
Country	US
Kind code	B2
Filing date	Feb 21, 2022
Priority date	Aug 22, 2019
Publication date	Sep 12, 2023
Grant date	Sep 12, 2023

Abstract

A radio station, in particular an access point, for client localization in a multipath indoor environment is disclosed. The radio station comprises: a circular antenna array comprising uniform circularly arranged antenna elements; and a processor configured to: transform first input data from the circular antenna array into second input data using a transform that transforms the first steering vector of the circular antenna array into a second steering vector of a virtual linear antenna array; and transform the second input data into third input data by using a transform that transforms the second steering vector of the virtual linear antenna array into a third steering vector of a second virtual linear antenna array, comprising a larger number of antenna elements than the virtual linear antenna array; and determine an angle of arrival based on the third input data.

First claim

What is claimed is:

1. An access point, comprising:
a circular antenna array comprising circularly and uniformly arranged antenna elements, wherein a first steering vector associated with the circular antenna array represents relative phases of the antenna elements of the circular antenna array, the relative phases of the antenna elements of the circular antenna array being relative to a reference point at an origin of the circular antenna array; and
a processor configured to:
receive first input data from the circular antenna array, wherein the first input data comprises channel state information;
transform the first input data into second input data using a transform that transforms the first steering vector of the circular antenna array into a second steering vector of a first virtual linear antenna array, wherein the first virtual linear array comprises uniformly and linearly arranged virtual antenna elements, wherein the second steering vector of the first virtual linear antenna array represents relative phases of the linearly arranged virtual antenna elements, the relative phases of the linearly arranged virtual antenna elements being relative to a reference antenna; and
transform the second input data into third input data using a transform that transforms the second steering vector of the virtual linear antenna array into a third steering vector of a second virtual linear antenna array, the second virtual linear array comprising a larger number of virtual antenna elements than the first virtual linear antenna array, and wherein the third steering vector of the second virtual antenna array is a function of angle of arrival and a time of flight; and
determine an angle of arrival of at least one path of a multipath indoor environment based on the third input data, by applying a two-dimensional multiple signal classification (MUSIC) algorithm over an angle of arrival and a time of flight domain over the third input data.

2. The access point of claim 1 , wherein the processor is configured to transform the first input data into the second input data by applying a weighted spatial discrete Fourier transform to the first input data.

3. The access point of claim 2 , wherein the processor is configured to apply a Bessel function for weighting the spatial discrete Fourier transform.

4. The access point of claim 1 , wherein a phase of the steering vector of the first virtual linear antenna array is a linear function of the angle of arrival.

5. The access point of claim 1 , wherein the processor is configured to transform the second input data into the third input data by using spatial smoothing.

6. The access point of claim 1 , wherein a dimension of the second virtual linear antenna array is based on a scaled product of number of virtual antenna elements of the first linear virtual antenna array and a number of subcarriers.

7. The access point of claim 6 , wherein the dimension of the second virtual linear antenna array is higher than a number of paths at a known multipath indoor environment.

8. The access point of claim 1 , wherein a size of the second virtual linear antenna array corresponds to a number of subcarriers times the number of subcarriers, up to a scaling factor.

9. The access point of claim 1 , wherein the processor is configured to determine the angle of arrival and the time of flight of the at least one path of the multipath indoor environment based on determining peaks of a two-dimensional MUSIC spectrum.

10. The access point of claim 9 , wherein the processor is configured to determine the two-dimensional MUSIC spectrum according to the following:

P

M
⁢
U

⁡

(

θ
,
τ

)

=

1



a
H

⁡

(

θ
,
τ

)

⁢

E
N

⁢

E
N
H

⁢

a
⁡

(

θ
,
τ

)



where α(θ, τ) is the third steering vector of the second virtual antenna array and E N is a noise subspace of a covariance matrix applied to the third input data.

11. The access point of claim 1 , wherein the processor is configured to determine a Line-Of-Sight path (LOS) of the multipath indoor environment based on angles of arrival and times of flight of all paths determined for the multipath indoor environment.

12. The access point of claim 1 , wherein the processor is configured to transform the first input data X into second input data {tilde over (X)} by applying a transform {tilde over (X)}=JFX with weight matrix J and spatial discrete Fourier transform matrix F as follows:

J
=

diag
⁡

(

M

j
m

⁢

J
m

⁡

(

k
0

⁢
r

)

)

F
=

[

1

w

-
h

Assignees

• Huawei Tech Co Ltd

Inventors

• Kobzantsev Alexander
• Ezri Doron
• Weitzman Avi
• Pan Chun
• Jiang Xingfeng
• Fu Jie

Classifications

• G01S3/74 Primary

  Multi-channel systems specially adapted for direction-finding, i.e. having a single antenna system capable of giving simultaneous indications of the directions of different signals (systems in which the directions of different signals are determined sequentially and displayed simultaneously G01S3/04, G01S3/14) · CPC title

• G01S3/48 Primary

  the waves arriving at the antennas being continuous or intermittent and the phase difference of signals derived therefrom being measured · CPC title

• H01Q3/30

  varying the {relative} phase {between the radiating elements of an array (H01Q3/2605, H01Q3/2658, H01Q3/2682, H01Q3/44 take precedence)} · CPC title