Transmission method, transmission device, reception method, and reception device
Provided is a precoding method for generating, from a plurality of baseband signals, a plurality of precoded signals to be transmitted over the same frequency bandwidth at the same time, including the steps of selecting a matrix F[i] from among N matrices, which define precoding performed on the plurality of baseband signals, while switching between the N matrices, i being an integer from 0 to N−1, and N being an integer at least two, generating a first precoded signal z1 and a second precoded signal z2, generating a first encoded block and a second encoded block using a predetermined error correction block encoding method, generating a baseband signal with M symbols from the first encoded block and a baseband signal with M symbols the second encoded block, and precoding a combination of the generated baseband signals to generate a precoded signal having M slots.
1. A transmission method comprising:
an encoding step of generating an encoded block using a predetermined error correction block encoding method;
a generation step of generating a first transmission signal z1 and a second transmission signal z2 by performing, for each of a plurality of slots, a precoding process on a first modulated signal s1 and a second modulated signal s2 that have been generated from the encoded block; and
a transmission step of transmitting the first transmission signal z1 and the second transmission signal z2 from a first antenna and a second antenna, respectively, in the same frequency at the same time, wherein
the generation step
further selects one matrix from among N matrices F[i], where i is an integer no less than 0 and no more than N−1, and N is an integer 3 or greater, by hopping between the matrices over each of the plurality of slots, the N matrices F[i] each defining the precoding process, and
generates the transmission signal z1 and the transmission signal z2 by performing, for each of the plurality of slots, a precoding process corresponding to the selected matrix F[i] on the first modulated signal s1 and the second modulated signal s2,
the first transmission signal z1 and the second transmission signal z2 satisfy (z1, z2) T =F[i](s1, s2) T ,
(z1, z2) T being a transposed vector of (z1, z2), and
(s1, s2) T being a transposed vector of (s1, s2),
the N matrices F[i] satisfy
F
[
i
]
=
1
α
2
+
1
(
ⅇ
jθ
11
(
i
)
α
×
ⅇ
j
(
θ
11
(
i
)
+
λ
)
α
×
ⅇ
jθ
21
(
i
)
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
where λ represents an arbitrary angle, and α represents a positive real number excluding 1,
θ 11 (i) and θ 21 (i) satisfy
e j(θ 11 (x)−θ 21 (x)) ≠e j(θ 11 (y)−θ 21 (y)) for ∀ x,∀y ( x≠y;x,y= 0,1,2 , . . . ,N− 2 ,N− 1), and
the generation step performs the generation corresponding to the encoded block by selecting each of the N matrices F[i] the same number of times.
2. The transmission method of claim 1 , wherein
θ 11 (i) and θ 21 (i) of the N matrices F[i] further satisfy either
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
)
or
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
)
.
3. A transmission apparatus comprising:
an encoding unit configured to generate an encoded block using a predetermined error correction block encoding method;
a generation unit configured to generate a first transmission signal z1 and a second transmission signal z2 by performing, for each of a plurality of slots, a precoding process on a first modulated signal s1 and a second modulated signal s2 that have been generated from the encoded block; and
a transmission unit configured to transmit the first transmission signal z1 and the second transmission signal z2 from a first antenna and a second antenna, respectively, in the same frequency at the same time, wherein
the generation unit
is further configured to select one matrix from among N matrices F[i], where i is an integer no less than 0 and no more than N−1, and N is an integer 3 or greater, by hopping between the matrices over each of the plurality of slots, the N matrices F[i] each defining the precoding process, and
generates the transmission signal z1 and the transmission signal z2 by performing, for each of the plurality of slots, a precoding process corresponding to the selected matrix F[i] on the first modulated signal s1 and the second modulated signal s2,
the first transmission signal z1 and the second transmission signal z2 satisfy (z1, z2) T =F[i](s1, s2) T ,
(z1, z2) T being a transposed vector of (z1, z2), and
(s1, s2) T being a transposed vector of (s1, s2),
the N matrices F[i] satisfy
F
[
i
]
=
1
α
2
+
1
(
ⅇ
jθ
11
(
i
)
α
×
ⅇ
j
(
θ
11
(
i
)
+
λ
)
α
×
ⅇ
jθ
21
(
i
)
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
where λ represents an arbitrary angle, and α represents a positive real number excluding 1,
θ 11 (i) and θ 21 (i) satisfy
e j(θ 11 (x)−θ 21 (x)) ≠e j(θ 11 (y)−θ 21 (y)) for ∀ x,∀y ( x≠y;x,y= 0,1,2 , . . . ,N− 2 ,N− 1), and
the generation unit performs the generation corresponding to the encoded block by selecting each of the N matrices F[i] the same number of times.
4. The transmission apparatus of claim 3 , wherein
θ 11 (i) and θ 21 (i) of the N matrices F[i] further satisfy either
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
)
or
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
)
.
5. A reception method comprising:
an acquisition step of acquiring a reception signal obtained by receiving a first transmission signal z1 and a second transmission signal z2 transmitted from a first antenna and a second antenna, respectively, in the same frequency at the same time, the first transmission signal z1 and the second transmission signal z2 having been generated as a result of a predetermined generation process performed on a first modulated signal s1 and a second modulated signal s2, the first modulated signal s1 and the second modulated signal s2 having been generated from an encoded block generated with use of a predetermined error correction block encoding method; and
a demodulation step of performing a demodulation process on the acquired reception signal, the demodulation process corresponding to the predetermined generation process, wherein
the predetermined generation process includes:
selecting one matrix from among N matrices F[i], where i is an integer no less than 0 and no more than N−1, and N is an integer 3 or greater, by hopping between the matrices over each of the plurality of slots, the N matrices F[i] defining a precoding process that is performed on a plurality of modulated signals, and
generating the transmission signal z1 and the transmission signal z2 by performing, for each of the plurality of slots, a precoding process corresponding to the selected matrix F[i] on the first modulated signal s1 and the second modulated signal s2,
the first transmission signal z1 and the second transmission signal z2 satisfy (z1, z2) T =F[i](s1, s2) T ,
(z1, z2) T being a transposed vector of (z1, z2), and
(s1, s2) T being a transposed vector of (s1, s2),
the N matrices F[i] satisfy
F
[
i
]
=
1
α
2
+
1
(
ⅇ
jθ
11
(
i
)
α
×
ⅇ
j
(
θ
11
(
i
)
+
λ
)
α
×
ⅇ
jθ
21
(
i
)
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
where λ represents an arbitrary angle, and α represents a positive real number excluding 1,
θ 11 (i) and θ 21 (i) satisfy
e j(θ 11 (x)−θ 21 (x)) ≠e j(θ 11 (y)−θ 21 (y)) for ∀ x,∀y ( x≠y;x,y= 0,1,2 , . . . ,N− 2 ,N− 1), and
in the predetermined generation process corresponding to the encoded block, each of the N matrices F[i] is selected the same number of times.
6. The reception method of claim 5 , wherein
θ 11 (i) and θ 21 (i) of the N matrices F[i] further satisfy either
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
)
or
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
)
.
7. A reception apparatus comprising:
an acquisition unit configured to acquire a reception signal obtained by receiving a first transmission signal z1 and a second transmission signal z2 transmitted from a first antenna and a second antenna, respectively, in the same frequency at the same time, the first transmission signal z1 and the second transmission signal z2 having been generated as a result of a predetermined generation process performed on a first modulated signal s1 and a second modulated signal s2, the first modulated signal s1 and the second modulated signal s2 having been generated from an encoded block generated with use of a predetermined error correction block encoding method; and
a demodulation unit configured to perform a demodulation process on the acquired reception signal, the demodulation process corresponding to the predetermined generation process, wherein
the predetermined generation process includes:
selecting one matrix from among N matrices F[i], where i is an integer no less than 0 and no more than N−1, and N is an integer 3 or greater, by hopping between the matrices over each of the plurality of slots, the N matrices F[i] defining a precoding process that is performed on a plurality of modulated signals, and
generating the transmission signal z1 and the transmission signal z2 by performing, for each of the plurality of slots, a precoding process corresponding to the selected matrix F[i] on the first modulated signal s1 and the second modulated signal s2,
the first transmission signal z1 and the second transmission signal z2 satisfy (z1, z2) T =F[i](s1, s2) T ,
(z1, z2) T being a transposed vector of (z1, z2), and
(s1, s2) T being a transposed vector of (s1, s2),
the N matrices F[i] satisfy
F
[
i
]
=
1
α
2
+
1
(
ⅇ
jθ
11
(
i
)
α
×
ⅇ
j
(
θ
11
(
i
)
+
λ
)
α
×
ⅇ
jθ
21
(
i
)
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
where λ represents an arbitrary angle, and α represents a positive real number excluding 1,
θ 11 (i) and θ 21 (i) satisfy
e j(θ 11 (x)−θ 21 (x)) ≠e j(θ 11 (y)−θ 21 (y)) for ∀ x,∀y ( x≠y;x,y= 0,1,2 , . . . ,N− 2 ,N− 1), and
in the predetermined generation process corresponding to the encoded block, each of the N matrices F[i] is selected the same number of times.
8. The reception apparatus of claim 7 , wherein
θ 11 (i) and θ 21 (i) of the N matrices F[i] further satisfy either
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
)
or
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
)
.