Precoding method, and transmitting device
View Patent ↗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 precoding method comprising:
selecting, using a weighting information generator, one matrix from among N matrices F[i], wherein N is an integer of 1 or greater and i is an integer of 1 or greater and no greater than N, by hopping between the N matrices over each of a plurality of slots, the N matrices F[i] defining a precoding process that is performed on a plurality of modulated signals; and
generating, using a precoding calculator, a first precoding signal z 1 and a second precoding signal z 2 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 s 1 generated from a coded block of bits by using a first modulation scheme and a second modulated signal s 2 generated from the coded block of bits by using the first modulation scheme,
the first precoding signal z 1 and the second precoding signal z 2 satisfying (z 1 , z 2 ) T =F[i] (s 1 , s 2 ) T , and
the N matrices F[i] being expressed by the following equation (1):
Math
5
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
)
)
Equation
279
wherein α is a real number smaller than 1,
λi takes a different value for each i, and
each of the N matrices F[i] is selected at least once in N slots,
wherein the first modulation scheme converts M bits into one symbol, M being an integer of 1 or greater, and
the coded block of bits is composed of (2×N×M×L) bits, L being an integer of 1 or greater.
2. A precoding apparatus comprising:
a weighting information generator configured to, in operation, select one matrix from among N matrices F[i], wherein N is an integer of 1 or greater and i is an integer of 1 or greater and no greater than N, by hopping between the N matrices over each of a plurality of slots, the N matrices F[i] defining a precoding process that is performed on a plurality of modulated signals; and
a precoding calculator configured to, in operation, generate a first precoding signal z 1 and a second precoding signal z 2 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 s 1 generated from a coded block of bits by using a first modulation scheme and a second modulated signal s 2 generated from the coded block of bits by using the first modulation scheme,
the first precoding signal z 1 and the second precoding signal z 2 satisfying (z 1 , z 2 ) T =F[i] (s 1 , s 2 ) T , and
the N matrices F[i] being expressed by the following equation (1):
Math
6
F
[
i
]
=
1
α
2
+
1
(
α
×
ⅇ
jθ
11
(
i
)
ⅇ
j
(
θ
11
(
i
)
+
λ
)
ⅇ
jθ
21
(
i
)
α
×
ⅇ
j
(
θ
21
(
i
)
+
λ
+
π
)
)
Equation
280
wherein α is a real number smaller than 1,
λi takes a different value for each i, and
each of the N matrices F[i] is selected at least once in N slots,
wherein the first modulation scheme converts M bits into one symbol, M being an integer of 1 or greater, and
the coded block of bits is composed of (2×N×M×L) bits, L being an integer of 1 or greater.