Receiving method and receiving apparatus
All data symbols used in data transmission of a modulated signal are precoded by switching between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol along the frequency axis and the time axis all differ. A modulated signal with such data symbols arranged therein is transmitted.
1. A reception method comprising:
acquiring a reception signal by obtaining a first transmission signal z1 and a second transmission signal z2 respectively transmitted from a first antenna and a second antenna at a same time at a same frequency, the first transmission signal z1 and the second transmission signal z2 being respectively generated by performing predetermined generation process on a first modulated signal s1 and a second modulated signal s2 that are each generated from an encoding block using a predetermined error correction block encoding method;
acquiring a reception quality information of the acquired reception signal;
displaying the acquired reception quality information; and
performing demodulation on the acquired reception signal according to the generation process to generate reception data, wherein
the generation process includes:
selecting a matrix F[i] from among N matrices while switching between the N matrices, for each of a plurality of slots, the N matrices each defining precoding performed on a plurality of modulated signals, i being an integer from 0 to N−1, and N being an integer 3 or greater; and
performing precoding defined by the selected matrix F[i] on each of the first modulated signal s1 and the second modulated signal s2 to generate the first transmission signal z1 and the second transmission signal z2,
the first transmission signal z1 and the second transmission signal z2 satisfy an equation (z1,z2) T =F[i](s1,s2) T ,
the N matrices satisfy an equation
F
[
i
]
=
1
α
2
+
1
(
ⅇ
j
θ
11
(
i
)
α
×
ⅇ
j
(
θ
11
(
i
)
+
λ
)
α
×
ⅇ
j
θ
21
(
i
)
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
where λ represents an arbitrary angle, and α represents a positive real number, and
θ 11 (i) and θ 21 (i) in the matrix F[i] satisfy one of equations
ⅇ
j
(
θ
11
(
x
+
1
)
-
θ
21
(
x
+
1
)
)
ⅇ
j
(
θ
11
(
x
)
-
θ
21
(
x
)
)
=
ⅇ
j
(
2
π
N
)
for
∀
x
(
x
=
0
,
1
,
2
,
…
,
N
-
2
)
and
ⅇ
j
(
θ
11
(
x
+
1
)
-
θ
21
(
x
+
1
)
)
ⅇ
j
(
θ
11
(
x
)
-
θ
21
(
x
)
)
=
ⅇ
j
(
-
2
π
N
)
for
∀
x
(
x
=
0
,
1
,
2
,
…
,
N
-
2
)
.
2. A reception apparatus comprising:
a reception signal acquisition unit configured to acquire a reception signal by obtaining a first transmission signal z1 and a second transmission signal z2 respectively transmitted from a first antenna and a second antenna at a same time at a same frequency, the first transmission signal z1 and the second transmission signal z2 being respectively generated by performing predetermined generation process on a first modulated signal s1 and a second modulated signal s2 that are each generated from an encoding block using a predetermined error correction block encoding method;
a reception quality information acquisition unit configured to acquire reception quality information of the acquired reception signal;
a display unit configured to display the acquired reception quality information; and
a demodulation unit configured to perform demodulation on the acquired reception signal according to the generation process to generate reception data, wherein
the generation process includes:
selecting a matrix F[i] from among N matrices while switching between the N matrices, for each of a plurality of slots, the N matrices each defining precoding performed on a plurality of modulated signals, i being an integer from 0 to N−1, and N being an integer 3 or greater; and
performing precoding defined by the selected matrix F[i] on each of the first modulated signal s1 and the second modulated signal s2 to generate the first transmission signal z1 and the second transmission signal z2,
the first transmission signal z1 and the second transmission signal z2 satisfy an equation (z1,z2) T =F[i](s1,s2) T ,
the N matrices satisfy an equation
F
[
i
]
=
1
α
2
+
1
(
ⅇ
j
θ
11
(
i
)
α
×
ⅇ
j
(
θ
11
(
i
)
+
λ
)
α
×
ⅇ
j
θ
21
(
i
)
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
where λ represents an arbitrary angle, and α represents a positive real number, and
θ 11 (i) and θ 21 (i) in the matrix F[i] satisfy one of equations
ⅇ
j
(
θ
11
(
x
+
1
)
-
θ
21
(
x
+
1
)
)
ⅇ
j
(
θ
11
(
x
)
-
θ
21
(
x
)
)
=
ⅇ
j
(
2
π
N
)
for
∀
x
(
x
=
0
,
1
,
2
,
…
,
N
-
2
)
and
ⅇ
j
(
θ
11
(
x
+
1
)
-
θ
21
(
x
+
1
)
)
ⅇ
j
(
θ
11
(
x
)
-
θ
21
(
x
)
)
=
ⅇ
j
(
-
2
π
N
)
for
∀
x
(
x
=
0
,
1
,
2
,
…
,
N
-
2
)
.