Signal generating method and signal generating device
View Patent ↗A transmission method for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. Each signal has been modulated according to a different modulation scheme. The transmission method applies precoding on both signals using a fixed precoding matrix, applies different power change to each signal, and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.
1. A transmission method comprising:
applying precoding to a first modulated signal s 1 and a second modulated signal s 2 to generate a first precoded signal z′ 1 and a second precoded signal z′ 2 , the first modulated signal s 1 having been modulated by a first modulation scheme at a modulation level denoted by a, the second modulated signal s 2 having been modulated by a second modulation scheme at a modulation level denoted by b, and a and b being integers satisfying a<b;
performing a phase change on at least one of the first precoded signal z′ 1 and the second precoded signal z′ 2 to generate a first transmission signal z 1 and a second transmission signal z 2 ; and
transmitting the first transmission signal z 1 and the second transmission signal z 2 respectively from a first antenna and a second antenna at the same time at the same frequency,
the precoding being represented by a precoding matrix
F
=
1
α
2
+
1
(
ⅇ
j
0
α
×
ⅇ
j
o
α
×
ⅇ
j
0
ⅇ
j
π
)
where α=0,
a phase change scheme for the phase change being changed regularly, and
the transmission method further comprising:
performing a power change involving multiplication by a weighting factor u a and multiplication by a weighting factor u b , the weighting factor u a being used for the generation of the first transmission signal z 1 from the first modulated signal s 1 , the weighting factor u b being used for the generation of the second transmission signal z 2 from the second modulated signal s 2 , and the weighting factor u a and the weighting factor u b satisfying u a <u b .
2. A transmission apparatus comprising:
a weighting unit applying precoding to a first modulated signal s 1 and a second modulated signal s 2 to generate a first precoded signal z′ 1 and a second precoded signal z′ 2 ,
a phase changer performing a phase change on at least one of the first precoded signal z′ 1 and the second precoded signal z′ 2 to generate a first transmission signal z 1 and a second transmission signal z 2 ; and
a transmission unit transmitting the first transmission signal z 1 and the second transmission signal z 2 respectively from a first antenna and a second antenna at the same time at the same frequency,
the first modulated signal s 1 having been modulated by a first modulation scheme at a modulation level denoted by a, the second modulated signal s 2 having been modulated by a second modulation scheme at a modulation level denoted by b, and a and b being integers satisfying a<b,
the precoding being represented by a precoding matrix
F
=
1
α
2
+
1
(
ⅇ
j
0
α
×
ⅇ
j
o
α
×
ⅇ
j
0
ⅇ
j
π
)
where α=0,
a phase change scheme for the phase change being changed regularly, and
the transmission apparatus further comprising:
a power changer performing a power change involving multiplication by a weighting factor u a and multiplication by a weighting factor u b , the weighting factor u a being used for the generation of the first transmission signal z 1 from the first modulated signal s 1 , the weighting factor u b being used for the generation of the second transmission signal z 2 from the second modulated signal s 2 , and the weighting factor u a and the weighting factor u b satisfying u a <u b .
3. A reception method comprising:
acquiring a reception signal obtained by receiving a first transmission signal z 1 and a second transmission signal z 2 respectively transmitted from a first antenna and a second antenna at the same time at the same frequency, the first transmission signal z 1 and the second transmission signal z 2 having been generated by a predetermined generation process; and
obtaining reception data by applying a demodulation process corresponding to the predetermined generation process to the reception signal,
the predetermined generation process including:
applying precoding to a first modulated signal s 1 and a second modulated signal s 2 to generate a first precoded signal z′ 1 and a second precoded signal z′ 2 ; and
performing a phase change on at least one of the first precoded signal z′ 1 and the second precoded signal z′ 2 to generate the first transmission signal z 1 and the second transmission signal z 2 ,
the first modulated signal s 1 having been modulated by a first modulation scheme at a modulation level denoted by a, the second modulated signal s 2 having been modulated by a second modulation scheme at a modulation level denoted by b, a and b being integers satisfying a<b,
the precoding being represented by a precoding matrix
F
=
1
α
2
+
1
(
ⅇ
j
0
α
×
ⅇ
j
o
α
×
ⅇ
j
0
ⅇ
j
π
)
where α=0,
a phase change scheme for the phase change being changed regularly, and
the predetermined generation process further including:
performing a power change involving multiplication by a weighting factor u a and multiplication by a weighting factor u b , the weighting factor u a being used for the generation of the first transmission signal z 1 from the first modulated signal s 1 , the weighting factor u b being used for the generation of the second transmission signal z 2 from the second modulated signal s 2 , and the weighting factor u a and the weighting factor u b satisfying u a <u b .
4. A reception apparatus comprising:
an acquiring unit acquiring a reception signal obtained by receiving a first transmission signal z 1 and a second transmission signal z 2 respectively transmitted from a first antenna and a second antenna at the same time at the same frequency, the first transmission signal z 1 and the second transmission signal z 2 having been generated by a predetermined generation process; and
a demodulator obtaining reception data by applying a demodulation process corresponding to the predetermined generation process to the reception signal,
the predetermined generation process including:
applying precoding to a first modulated signal s 1 and a second modulated signal s 2 to generate a first precoded signal z′ 1 and a second precoded signal z′ 2 ; and
performing a phase change on at least one of the first precoded signal z′ 1 and the second precoded signal z′ 2 to generate the first transmission signal z 1 and the second transmission signal z 2 ,
the first modulated signal s 1 having been modulated by a first modulation scheme at a modulation level denoted by a, the second modulated signal s 2 having been modulated by a second modulation scheme at a modulation level denoted by b, a and b being integers satisfying a<b,
the precoding being represented by a precoding matrix
F
=
1
α
2
+
1
(
ⅇ
j
0
α
×
ⅇ
j
o
α
×
ⅇ
j
0
ⅇ
j
π
)
where α=0,
a phase change scheme for the phase change being changed regularly, and
the predetermined generation process further including:
performing a power change involving multiplication by a weighting factor u a and multiplication by a weighting factor u b , the weighting factor u a being used for the generation of the first transmission signal z 1 from the first modulated signal s 1 , the weighting factor u b being used for the generation of the second transmission signal z 2 from the second modulated signal s 2 , and the weighting factor u a and the weighting factor u b satisfying u a <u b .