Transmission method, transmitter apparatus, reception method and receiver apparatus
View Patent ↗Transmission quality is improved in an environment in which direct waves dominate in a transmission method for transmitting a plurality of modulated signals from a plurality of antennas at the same time. All data symbols used in data transmission of a modulated signal are precoded by hopping between precoding matrices so that the precoding matrix used to precode each data symbol and the precoding matrices used to precode data symbols that are adjacent to the data symbol in the frequency domain and the time domain all differ. A modulated signal with such data symbols arranged therein is transmitted.
1. A transmission method comprising:
generating a first modulation signal s1 by using a first modulation scheme;
generating a second modulation signal s2 by using a second modulation scheme;
regularly switching between a plurality of precoding matrices for generating a first precoded signal z1 and a second precoded signal z2;
generating the first precoded signal z1 and the second precoded signal z2 by applying one of the plurality of precoding matrices to the first modulation signal s1 and the second modulation signal s2;
transmitting the first precoded signal z1 from one or more first antennas; and
transmitting the second precoded signal z2 from one or more second antennas, the second antennas being different from the first antennas, wherein
the first precoded signal z1 includes a first symbol and a second symbol that is adjacent to the first symbol in a frequency domain,
the second precoded signal z2 includes a third symbol and a fourth symbol that is adjacent to the third symbol in the frequency domain,
the first symbol and the third symbol are transmitted at a first frequency,
the second symbol and the fourth symbol are transmitted at a second frequency, and
a first precoding matrix for the first symbol and the third symbol and a second precoding matrix for the second symbol and the fourth symbol are different from each other.
2. The transmission method of claim 1 , wherein
a maximum amplitude of the first modulation signal s1 is different from a maximum amplitude of the second modulation signal s2.
3. A transmission device comprising:
a modulation unit generating a first modulation signal s1 by using a first modulation scheme, and generating a second modulation signal s2 by using a second modulation scheme;
a precoding weight generation unit regularly switching between a plurality of precoding matrices for generating a first precoded signal z1 and a second precoded signal z2, and
a weighting unit generating the first precoded signal z1 and the second precoded signal z2 by applying one of the plurality of precoding matrices to the first modulation signal s1 and the second modulation signal s2; and
a transmission unit transmitting the first precoded signal z1 from one or more first antennas, and transmitting the second precoded signal z2 from one or more second antennas, the second antennas being different from the first antennas, wherein
the weighting unit generates the first precoded signal z1 that includes a first symbol and a second symbol that is adjacent to the first symbol in a frequency domain, and generates the second precoded signal z2 that includes a third symbol and a fourth symbol that is adjacent to the third symbol in the frequency domain,
the transmission unit transmits the first symbol and the third symbol at a first frequency and the second symbol and the fourth symbol at a second frequency, and
the precoding weight generation unit switches a first precoding matrix for the first symbol and the third symbol to a second precoding matrix for the second symbol and the fourth symbol, the first precoding matrix and the second precoding matrix being different from each other.
4. The transmission device of claim 3 , wherein
the modulation unit includes
a first multiplication unit multiplying an amplitude of the first modulation signal s1 by a first coefficient, and
a second multiplication unit multiplying an amplitude of the second modulation signal s2 by a second coefficient.
5. A reception method comprising:
receiving, by using one or more antennas, a signal including a first transmission signal z1 and a second transmission signal z2 precoded and transmitted from a transmission device;
demodulating the received signal by using a demodulation scheme corresponding to one or more predetermined modulation schemes; and
obtaining data from the demodulated signal by performing predetermined error-correction decoding, wherein
the first transmission signal z1 and the second transmission signal z2 are signals generated by applying a precoding matrix to a first modulation signal s1 and a second modulation signal s2, the precoding matrix being regularly switched between a plurality of precoding matrices, the first modulation signal s1 being a signal modulated by using a first modulation scheme from among the one or more predetermined modulation schemes, the second modulation signal s2 being a signal modulated by using a second modulation scheme from among the one or more predetermined modulation schemes,
the first transmission signal z1 includes a first symbol and a second symbol that is adjacent to the first symbol in a frequency domain,
the second transmission signal z2 includes a third symbol and a fourth symbol that is adjacent to the third symbol in the frequency domain,
the first symbol and the third symbol are transmitted at a first frequency,
the second symbol and the fourth symbol are transmitted at a second frequency, and
a first precoding matrix for the first symbol and the third symbol and a second precoding matrix for the second symbol and the fourth symbol are different from each other.
6. The reception method of claim 5 , wherein
a maximum amplitude of the first modulation signal s1 is different from a maximum amplitude of the second modulation signal s2.
7. A reception device comprising:
a reception unit receiving, by using one or more antennas, a signal including a first transmission signal z1 and a second transmission signal z2 precoded and transmitted from a transmission device;
a demodulation unit demodulating the received signal by using a demodulation scheme corresponding to one or more predetermined modulation schemes; and
an error correction unit obtaining data from the demodulated signal by performing predetermined error-correction decoding, wherein
the first transmission signal z1 and the second transmission signal z2 are signals generated by applying a precoding matrix to a first modulation signal s1 and a second modulation signal s2, the precoding matrix being regularly switched between a plurality of precoding matrices, the first modulation signal s1 being a signal modulated by using a first modulation scheme from among the one or more predetermined modulation schemes, the second modulation signal s2 being a signal modulated by using a second modulation scheme from among the one or more predetermined modulation schemes,
the first transmission signal z1 includes a first symbol and a second symbol that is adjacent to the first symbol in a frequency domain,
the second transmission signal z2 includes a third symbol and a fourth symbol that is adjacent to the third symbol in the frequency domain,
the first symbol and the third symbol are transmitted at a first frequency,
the second symbol and the fourth symbol are transmitted at a second frequency, and
a first precoding matrix for the first symbol and the third symbol and a second precoding matrix for the second symbol and the fourth symbol are different from each other.
8. The reception device of claim 7 , wherein
a maximum amplitude of the first modulation signal s1 is different from a maximum amplitude of the second modulation signal s2.