Signal generation method and signal generation device
A transmission method simultaneously transmitting a first modulated signal and a second modulated signal at a common frequency performs precoding on both signals using a fixed precoding matrix 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:
coding information to generate coded data blocks based on low-density parity-check (LDPC) coding scheme and Bose-Chaudhuri-Hocquenghem (BCH) coding scheme;
performing modulation, precoding, and phase-change on the coded data blocks to generate a first transmission signal and a second transmission signal; and
transmitting the first transmission signal and the second transmission signal from a first antenna and a second antenna, respectively, at a same frequency band and a same time, wherein the precoding is performed according to a fixed matrix F expressed as:
1
α
2
+
1
(
e
j
0
α
×
e
j
0
α
×
e
j
0
e
j
π
)
,
and
the phase-change is performed such that a phase change amount regularly varies for every slot and the phase change amount is initialized for every coded data block,
wherein α is a real value, e is a base of a natural logarithm, j is an imaginary unit, and π is the constant pi.
2. The transmission method according to claim 1 , wherein the phase change amount is initialized to be equal to 0 radian at the first slot.
3. A reception method comprising:
receiving a first transmission signal and a second transmission signal that have been transmitted from a first antenna and a second antenna, respectively, at a same frequency band and a same time, the first transmission signal and the second transmission signal having been generated by a generation process; and
demodulating the first transmission signal and the second transmission signal to obtain information, wherein
the generation process comprises:
coding the information to generate coded data blocks based on low-density parity-check (LDPC) coding scheme and Bose-Chaudhuri-Hocquenghem (BCH) coding scheme; and
performing modulation, precoding, and phase-change on the coded data blocks to generate a first transmission signal and a second transmission signal,
the precoding is performed according to a fixed matrix F expressed as:
1
α
2
+
1
(
e
j
0
α
×
e
j
0
α
×
e
j
0
e
j
π
)
,
and
the phase-change is performed such that a phase change amount regularly varies for every slot and the phase change amount is initialized for every coded data block,
wherein α is a real value, e is a base of a natural logarithm, j is an imaginary unit, and π is the constant pi.
4. The reception method according to claim 3 , wherein the phase change amount is initialized to be equal to 0 radian at the first slot.
5. A transmission method comprising:
coding information to generate coded data blocks based on low-density parity-check (LDPC) coding scheme and Bose-Chaudhuri-Hocquenghem (BCH) coding scheme;
performing modulation, precoding, and phase-change on the coded data blocks to generate a first transmission signal and a second transmission signal; and
transmitting the first transmission signal and the second transmission signal from a first antenna and a second antenna, respectively, at a same frequency band and a same time, wherein
the precoding is performed according to a fixed matrix F expressed as:
1
α
2
+
1
(
e
j
0
α
×
e
j
0
α
×
e
j
0
e
j
π
)
,
the phase-change is performed on first symbols and second symbols on which the modulation and the precoding have been performed and which are provided in respective slots, and
the phase-change is performed such that:
a phase change amount regularly varies for every pair of a first symbol and a second symbol in a corresponding slot; and
the phase change amount is initialized for every coded data block,
wherein α is a real value, e is a base of a natural logarithm, j is an imaginary unit, and π is the constant pi.
6. The transmission method according to claim 5 , wherein the phase change amount is initialized to be equal to 0 radian at the first slot.