Broadcast signal transmission method, broadcast signal transmission apparatus, broadcast signal reception method, and broadcast signal reception apparatus
Disclosed is a transmission scheme for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. According to the transmission scheme, a precoding weight multiplying unit multiplies a precoding weight by a baseband signal after a first mapping and a baseband signal after a second mapping and outputs the first modulated signal and the second modulated signal. In the precoding weight multiplying unit, precoding weights are regularly hopped.
1. A broadcast signal transmission method comprising:
selecting one matrix from among N matrices F[i], wherein N is equal to an integer 9 and i is equal to an integer no less than 0 and no more than 8, by regularly hopping a phase change of 2π/N, each of the N matrices F[i] being selected at least once in N slots in order to increase a capacity of reception data, the N matrices F[i] defining a precoding process that is performed on a plurality of modulated signals; and
generating a first broadcast signal z1 and a second broadcast signal z2 for each of the plurality of slots by performing a precoding process, which corresponds to the matrix selected from among the N matrices F[i], on a first modulated signal s1 generated from a first set of bits including first video data or first audio data and a second modulated signal s2 generated from a second set of bits including second video data or second audio data; and
transmitting the first broadcast signal z1 and the second broadcast signal z2 from a first antenna and a second antenna, respectively, in a broadcast frequency,
the first broadcast signal z1 and the second broadcast signal z2 satisfying (z1, z2) T =F[i] (s1, s2) T , and
the N matrices F[i] being expressed by the following equations:
F
[
i
=
0
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j0
ⅇ
jπ
)
,
F
[
i
=
1
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
2
9
π
ⅇ
j
(
2
9
π
+
π
)
)
,
F
[
i
=
2
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
4
9
π
ⅇ
j
(
4
9
π
+
π
)
)
,
F
[
i
=
3
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
6
9
π
ⅇ
j
(
6
9
π
+
π
)
)
,
F
[
i
=
4
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
8
9
π
ⅇ
j
(
8
9
π
+
π
)
)
,
F
[
i
=
5
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
10
9
π
ⅇ
j
(
10
9
π
+
π
)
)
,
F
[
i
=
6
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
12
9
π
ⅇ
j
(
12
9
π
+
π
)
)
,
F
[
i
=
7
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
14
9
π
ⅇ
j
(
14
9
π
+
π
)
)
,
and
F
[
i
=
8
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
16
9
π
ⅇ
j
(
16
9
π
+
π
)
)
,
wherein α is a positive real number.
2. A broadcast signal transmission apparatus comprising:
weighting information generating circuitry which, in operation, selects one matrix from among N matrices F[i], wherein N is equal to an integer 9 and i is equal to an integer no less than 0 and no more than 8, by regularly hopping a phase change of 2π/N, each of the N matrices F[i] being selected at least once in N slots in order to increase a capacity of reception data, the N matrices F[i] defining a precoding process that is performed on a plurality of modulated signals;
weighting circuitry which, in operation, generates a first broadcast signal z1 and a second broadcast signal z2 for each of the plurality of slots by performing a precoding process, which corresponds to the matrix selected from among the N matrices F[i], on a first modulated signal s1 generated from a first set of bits including first video data or first audio data and a second modulated signal generated from a second set of bits including second video data or second audio data; and
transmission circuitry which, in operation, transmits the first broadcast signal z1 and the second broadcast signal z2 from a first antenna and a second antenna, respectively, in a broadcast frequency,
the first broadcast signal z1 and the second broadcast signal z2 satisfying (z1, z2) T =F[i] (s1, s2) T , and
the N matrices F[i] being expressed by the following equations:
F
[
i
=
0
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j0
ⅇ
jπ
)
,
F
[
i
=
1
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
2
9
π
ⅇ
j
(
2
9
π
+
π
)
)
,
F
[
i
=
2
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
4
9
π
ⅇ
j
(
4
9
π
+
π
)
)
,
F
[
i
=
3
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
6
9
π
ⅇ
j
(
6
9
π
+
π
)
)
,
F
[
i
=
4
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
8
9
π
ⅇ
j
(
8
9
π
+
π
)
)
,
F
[
i
=
5
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
10
9
π
ⅇ
j
(
10
9
π
+
π
)
)
,
F
[
i
=
6
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
12
9
π
ⅇ
j
(
12
9
π
+
π
)
)
,
F
[
i
=
7
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
14
9
π
ⅇ
j
(
14
9
π
+
π
)
)
,
and
F
[
i
=
8
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
16
9
π
ⅇ
j
(
16
9
π
+
π
)
)
,
wherein α is a positive real number.
3. A broadcast signal reception method comprising:
acquiring a reception signal including video data or audio data, the reception signal being obtained by receiving a first broadcast signal z1 and a second broadcast signal z2 respectively transmitted from a first antenna and a second antenna in the same broadcast frequency at the same time, the first broadcast signal z1 and the second broadcast signal z2 being generated through determined generation processing; and
generating reception data by performing demodulation processing on the acquired reception signal,
the determined generation processing involving:
selecting one matrix from among N matrices F[i], wherein N is equal to an integer 9 and i is equal to an integer no less than 0 and no more than 8, by regularly hopping a phase change of 2π/N, each of the N matrices F[i] being selected at least once in N slots in order to increase a capacity of reception data, the N matrices F[i] defining a precoding process that is performed on a plurality of modulated signals; and
generating the first broadcast signal z1 and the second broadcast signal z2 for each of the plurality of slots by performing a precoding process, which corresponds to the matrix selected from among the N matrices F[i], on a first modulated signal s1 generated from a first set of bits including first video data or first audio data and a second modulated signal s2 generated from a second set of bits including second video data or second audio data,
the first broadcast signal z1 and the second broadcast signal z2 satisfying (z1, z2) T =F[i] (s1, s2) T , and
the N matrices F[i] being expressed by the following equations:
F
[
i
=
0
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j0
ⅇ
jπ
)
,
F
[
i
=
1
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
2
9
π
ⅇ
j
(
2
9
π
+
π
)
)
,
F
[
i
=
2
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
4
9
π
ⅇ
j
(
4
9
π
+
π
)
)
,
F
[
i
=
3
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
6
9
π
ⅇ
j
(
6
9
π
+
π
)
)
,
F
[
i
=
4
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
8
9
π
ⅇ
j
(
8
9
π
+
π
)
)
,
F
[
i
=
5
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
10
9
π
ⅇ
j
(
10
9
π
+
π
)
)
,
F
[
i
=
6
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
12
9
π
ⅇ
j
(
12
9
π
+
π
)
)
,
F
[
i
=
7
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
14
9
π
ⅇ
j
(
14
9
π
+
π
)
)
,
and
F
[
i
=
8
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
16
9
π
ⅇ
j
(
16
9
π
+
π
)
)
,
wherein α is a positive real number.
4. A broadcast signal reception apparatus comprising:
acquiring circuitry which, in operation, acquires a reception signal including video data or audio data, the reception signal being obtained by receiving a first broadcast signal z1 and a second broadcast signal z2 respectively transmitted from a first antenna and a second antenna in the same broadcast frequency at the same time, the first broadcast signal z1 and the second broadcast signal z2 being generated through determined generation processing;
generating circuitry which, in operation, generates the reception data by performing demodulation processing on the acquired reception signal,
the determined generation processing involving:
selecting one matrix from among N matrices F[i], wherein N is equal to an integer 9 and i is equal to an integer no less than 0 and no more than 8, by regularly hopping a phase change of 2π/N, each of the N matrices F[i] being selected at least once in N slots in order to increase a capacity of reception data, the N matrices F[i] defining a precoding process that is performed on a plurality of modulated signals; and
generating the first broadcast signal z1 and the second broadcast signal z2 for each of the plurality of slots by performing a precoding process, which corresponds to the matrix selected from among the N matrices F[i], on a first modulated signal s1 generated from a first set of bits including first video data or first audio data and a second modulated signal s2 generated from a second set of bits including second video data or second audio data,
the first broadcast signal z1 and the second broadcast signal z2 satisfying (z1, z2) T =F[i] (s1, s2) T , and
the N matrices F[i] being expressed by the following equations:
F
[
i
=
0
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j0
ⅇ
jπ
)
,
F
[
i
=
1
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
2
9
π
ⅇ
j
(
2
9
π
+
π
)
)
,
F
[
i
=
2
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
4
9
π
ⅇ
j
(
4
9
π
+
π
)
)
,
F
[
i
=
3
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
6
9
π
ⅇ
j
(
6
9
π
+
π
)
)
,
F
[
i
=
4
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
8
9
π
ⅇ
j
(
8
9
π
+
π
)
)
,
F
[
i
=
5
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
10
9
π
ⅇ
j
(
10
9
π
+
π
)
)
,
F
[
i
=
6
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
12
9
π
ⅇ
j
(
12
9
π
+
π
)
)
,
F
[
i
=
7
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
14
9
π
ⅇ
j
(
14
9
π
+
π
)
)
,
and
F
[
i
=
8
]
=
1
α
2
+
1
(
ⅇ
j0
α
×
ⅇ
j0
α
×
ⅇ
j
16
9
π
ⅇ
j
(
16
9
π
+
π
)
)
,
wherein α is a positive real number.