Communication device, information processing method, and storage medium

Patent metadata

Field	Value
Publication number	US-11240069-B2
Application number	US-202117155746-A
Country	US
Kind code	B2
Filing date	Jan 22, 2021
Priority date	Jan 31, 2020
Publication date	Feb 1, 2022
Grant date	Feb 1, 2022

Abstract

A communication device is configured to correlate a first signal with a second signal at a designated interval, the second signal corresponding to the first signal and being received by the communication device where the other communication device transmits a signal including a pulse as the first signal, convert a correlation computation result that is a result of correlating the first signal with the second signal at the designated interval into a format including a matrix product of an expanded modal matrix and an expanded signal vector, the expanded modal matrix including a plurality of elements indicating the correlation computation result obtained when assuming that the signals are received at respective set times, the expanded signal vector being a vector including a plurality of elements, each of which indicates whether or not there is a signal received at each of the set times and amplitude and phase of the signal.

First claim

What is claimed is:

1. A communication device, comprising:
a wireless communicator configured to wirelessly receive a signal from another communication device; and
a controller configured to
correlate a first signal with a second signal at a designated interval, the second signal corresponding to the first signal and being received by the wireless communicator in a case where the other communication device transmits a signal including a pulse as the first signal,
convert a correlation computation result that is a result of correlating the first signal with the second signal at the designated interval into a format including a matrix product of an expanded modal matrix and an expanded signal vector, the expanded modal matrix being a matrix including a plurality of elements indicating the correlation computation result obtained when assuming that the second signal is received at respective set times, the expanded signal vector being a vector including a plurality of elements, each of which indicates whether or not there is the second signal received at each of the set times and amplitude and a phase of the second signal, and
estimate reception time of the second signal on a basis of the set times corresponding to the plurality of elements of the expanded signal vector,

wherein an interval between the set times is shorter than the designated interval.

2. The communication device according to claim 1 ,
wherein the controller estimates a set time corresponding to a nonzero element as reception time of the second signal, among the set times corresponding to the plurality of elements of the expanded signal vector.

3. The communication device according to claim 2 ,
wherein the controller estimates a sparse solution of the expanded signal vector and estimates a set time corresponding to the nonzero element as the reception time of the second signal among the sparse solution of the expanded signal vector,
the sparse solution is a vector including a predetermined number of the nonzero elements, and
the predetermined number is a number of pulses included in the second signal as pulses corresponding to the single pulse included in the first signal.

4. The communication device according to claim 3 ,
wherein the controller estimates an earliest set time as the reception time of the second signal among the set times corresponding to the nonzero elements included in the sparse solution of the expanded signal vector that has been estimated.

5. The communication device according to claim 3 ,
wherein the controller estimates a weighted minimum norm solution as estimation of the sparse solution of the expanded signal vector, the weighted minimum norm solution being a vector that minimizes a norm of a vector obtained by weighting the expanded signal vector.

6. The communication device according to claim 5 ,
wherein the controller estimates the weighted minimum norm solution by iteratively calculating an equation (1), an equation (2), and an equation (3):

W
k

=

diag
⁡

(



s

k
-
1



1
-

p
2

)

(
1
)

q
k

=

(

AW
k

)

-

⁢
z

(
2
)

s
k

=

W
k

⁢

q
k

(
3
)

where k is the number of iterations, s k is a candidate for the weighted minimum norm solution, p is a constant that is 0 or more and 1 or less, A is the expanded modal matrix, (AW K ) − is a generalized inverse matrix of AW k , W k is a weighting matrix at the number of iterations k, z is the correlation computation result, q k is a vector given by the equation (2), and an initial value of s k is given by an equation (4)
S| k=0 =S mn   (4)

where s mn is the expanded signal vector that minimizes the norm of the expanded signal vector.

7. The communication device according to claim 6 ,
wherein the controller estimates the weighted minimum norm solution by substituting 0 for p in the equation (1).

8. The communication device according to claim 6 ,
wherein the controller decomposes AW k in the equation (2) into a format including a diagonal matrix through singular value decomposition, and calculates (AW k ) − , the diagonal matrix including singular values that are larger than a predetermined threshold.

9. The communication device according to claim 6 , wherein the controller uses an equation (5) instead of the equation (2),
q k =A k H ( A k A k H ) −1 Z
with A k =AW k   (5)

where A k H is an adjoint matrix of A k .

10. The communication device according to claim 9 ,
wherein the controller uses an equation (6) instead of the equation (5),
q k =A k H ( A k A k H +αI ) −1 Z
with A k =AW k   (6)

where α is a positive infinitesimal, and I is an identity matrix.

11. The communication device according to claim 6 ,
wherein the controller substitutes 0 for an element that is a predetermined threshold or less among elements included in W k in the equation (1).

12. The communication device according to claim 3 ,
wherein the controller estimates a weighted minimum norm solution as estim

Assignees

• Tokai Rika Co Ltd
• Nagoya Inst Tech

Inventors

• Oishi Yoshiki
• Koga Kenichi
• Koike Tatsuya
• Kikuma Nobuyoshi

Classifications

• H04L25/0212

  of impulse response · CPC title

• H04W4/025

  using location based information parameters · CPC title

• H04L27/2647

  Arrangements specific to the receiver only (equalisation H04L27/01) · CPC title

• G01S11/02

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

• H04L25/0248

  Eigen-space methods · CPC title