Transmission device and transmission method
View Patent ↗A first transmission signal and a second transmission signal are generated from a first modulated signal and a second modulated signal by using a precoding matrix, and parameters of the precoding matrix are calculated from feedback information.
1. A transmission method, comprising:
generating a first transmission signal z 1 (t) and a second transmission signal z 2 ( t ) by calculating Equation (1):
[
MATH
.
1
]
(
z
1
(
t
)
z
2
(
t
)
)
=
(
a
0
0
b
)
(
cos
θ
sin
θ
sin
θ
-
cos
θ
)
(
s
1
(
t
)
s
2
(
t
)
)
(
1
)
from a first modulated signal s 1 (t) and a second modulated signal S 2 ( t ); and
transmitting the first transmission signal z 1 (t) from a first transmission antenna, and transmitting the second transmission signal z 2 (t) from a second transmission antenna having a different polarization than the first transmission antenna,
wherein θ, a, and b are derived based on feedback information, and θ, a, and b satisfy:
[
MATH
.
2
]
b
=
h
11
(
t
)
h
22
(
t
)
×
a
and
θ
=
-
δ
+
n
π
radians
(
n
is
an
integer
)
,
wherein h 11 (t) represents channel characteristics between the first transmission antenna and a first reception antenna having the same polarization as the first transmission antenna at a receiver side,
wherein h 22 (t) represents channel characteristics between the second transmission antenna and a second reception antenna having the same polarization as the second transmission antenna at the receiver side, and
wherein δ is an angle between the first reception antenna and the second reception antenna in an ideal state and the first reception antenna and the second reception antenna when in a reception antenna state in which the first reception antenna and the second reception antenna are actually installed or when the reception antenna state is changed.
2. A transmission device, comprising:
a signal processor that generates a first transmission signal z 1 (t) and a second transmission signal z 2 ( t ) by calculating Equation (1):
[
MATH
.
3
]
(
z
1
(
t
)
z
2
(
t
)
)
=
(
a
0
0
b
)
(
cos
θ
sin
θ
sin
θ
-
cos
θ
)
(
s
1
(
t
)
s
2
(
t
)
)
(
1
)
from a first modulated signal s 1 (t) and a second modulated signal s 2 ( t ); and
a transmitter that transmits the first transmission signal z 1 (t) from a first transmission antenna, and transmits the second transmission signal z 2 ( t ) from a second transmission antenna having a different polarization than the first transmission antenna,
wherein θ, a, and b are derived based on feedback information, and θ, a, and b satisfy:
b
=
h
11
(
t
)
h
22
(
t
)
×
a
and
θ
=
-
δ
+
n
π
radians
(
n
is
an
integer
)
,
[
MATH
.
4
]
wherein h 11 (t) represents channel characteristics between the first transmission antenna and a first reception antenna having the same polarization as the first transmission antenna at a receiver side,
wherein h 22 (t) represents channel characteristics between the second transmission antenna and a second reception antenna having the same polarization as the second transmission antenna at the receiver side, and
wherein δ is an angle between the first reception antenna and the second reception antenna in an ideal state and the first reception antenna and the second reception antenna when in a reception antenna state in which the first reception antenna and the second reception antenna are actually installed or when the reception antenna state is changed.