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US 8,942,304 B2Granted
Signal generating method and signal generating device
AssigneePanasonic Intellectual Property Corporation of America
InventorsYutaka Murakami, Tomohiro Kimura, Mikihiro Ouchi
Life of this patent
Estimating the term…
Abstract
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.
Claims4
A transmission method comprising:
- applying precoding to a first modulated signal s1 and a second modulated signal s2 to generate a first precoded signal z′1 and a second precoded signal z′2, the first modulated signal s1 having been modulated by a first modulation scheme at a modulation level denoted by a, the second modulated signal s2 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 z1 and a second transmission signal z2;
- and
- transmitting the first transmission signal z1 and the second transmission signal z2 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 ua and multiplication by a weighting factor ub, the weighting factor ua being used for the generation of the first transmission signal z1 from the first modulated signal s1, the weighting factor ub being used for the generation of the second transmission signal z2 from the second modulated signal s2, and the weighting factor ua and the weighting factor ub satisfying ua<ub.
40 more elements
A transmission apparatus comprising:
- a weighting unit applying precoding to a first modulated signal s1 and a second modulated signal s2 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 z1 and a second transmission signal z2;
- and
- a transmission unit transmitting the first transmission signal z1 and the second transmission signal z2 respectively from a first antenna and a second antenna at the same time at the same frequency,
- the first modulated signal s1 having been modulated by a first modulation scheme at a modulation level denoted by a, the second modulated signal s2 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 ua and multiplication by a weighting factor ub, the weighting factor ua being used for the generation of the first transmission signal z1 from the first modulated signal s1, the weighting factor ub being used for the generation of the second transmission signal z2 from the second modulated signal s2, and the weighting factor ua and the weighting factor ub satisfying ua<ub.
41 more elements
A reception method comprising:
- acquiring a reception signal obtained by receiving a first transmission signal z1 and a second transmission signal z2 respectively transmitted from a first antenna and a second antenna at the same time at the same frequency, the first transmission signal z1 and the second transmission signal z2 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 s1 and a second modulated signal s2 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 z1 and the second transmission signal z2,
- the first modulated signal s1 having been modulated by a first modulation scheme at a modulation level denoted by a, the second modulated signal s2 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 ua and multiplication by a weighting factor ub, the weighting factor ua being used for the generation of the first transmission signal z1 from the first modulated signal s1, the weighting factor ub being used for the generation of the second transmission signal z2 from the second modulated signal s2, and the weighting factor ua and the weighting factor ub satisfying ua<ub.
44 more elements
A reception apparatus comprising:
- an acquiring unit acquiring a reception signal obtained by receiving a first transmission signal z1 and a second transmission signal z2 respectively transmitted from a first antenna and a second antenna at the same time at the same frequency, the first transmission signal z1 and the second transmission signal z2 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 s1 and a second modulated signal s2 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 z1 and the second transmission signal z2,
- the first modulated signal s1 having been modulated by a first modulation scheme at a modulation level denoted by a, the second modulated signal s2 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 ua and multiplication by a weighting factor ub, the weighting factor ua being used for the generation of the first transmission signal z1 from the first modulated signal s1, the weighting factor ub being used for the generation of the second transmission signal z2 from the second modulated signal s2, and the weighting factor ua and the weighting factor ub satisfying ua<ub.
44 more elements
Dependencies are inferred from the claim text.