Signal generating method and signal generating apparatus
AssigneeSun Patent Trust
InventorsYutaka Murakami, Tomohiro Kimura, Mikihiro Ouchi
Life of this patent
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Abstract
A transmission method for simultaneously transmitting a first modulated signal and a second modulated signal at the same frequency includes performing precoding on both signals using a fixed precoding matrix and regularly changing the phase of at least one of the signals. In this method, the power ratio between a plurality of signals transmitted from a plurality of antennas at the same frequency and at the same time differs from the power ratio between a plurality of pilot signals transmitted from the plurality of antennas at the same frequency and at the same time, whereby the accuracy of channel estimation by a reception device is improved.
Claims10
A transmission apparatus comprising:
- a first modulator that generates a first modulation signal by modulating a first data sequence with a first modulation scheme;
- a second modulator that generates a second modulation signal by modulating a second data sequence with a second modulation scheme which has an amount of signal points greater than the first modulation scheme, an average transmission power of the second modulation signal being the same as an average transmission power of the first modulation signal;
- a power adjuster that (i) adjusts an amplitude of the first modulation signal and (ii) adjusts an amplitude of the second modulation signal;
- a pre-coder that (i) generates a first pre-coding signal using the adjusted first modulation signal and the adjusted second modulation signal with a predetermined pre-coding matrix and (ii) generates a second pre-coding signal using the adjusted first modulation signal and the adjusted second modulation signal with the predetermined pre-coding matrix;
- a first transmitter transmits the first pre-coding signal from a first antenna at a first time and a first frequency;
- and
- a second transmitter transmits the second pre-coding signal from a second antenna at the first time and the first frequency, wherein
- a second minimum distance between each signal point of the adjusted second modulation signal on an I-Q plane is shorter than a first minimum distance between each signal point of the adjusted first modulation signal on an I-Q plane.
A transmission method comprising:
- generating a first modulation signal by modulating a first data sequence with a first modulation scheme;
- generating a second modulation signal by modulating a second data sequence with a second modulation scheme which has an amount of signal points greater than the first modulation scheme, an average transmission power of the second modulation signal being the same as an average transmission power of the first modulation signal;
- adjusting an amplitude of the first modulation signal;
- adjusting an amplitude of the second modulation signal;
- generating a first pre-coding signal using the adjusted first modulation signal and the adjusted second modulation signal with a predetermined pre-coding matrix;
- generating a second pre-coding signal using the adjusted first modulation signal and the adjusted second modulation signal with the predetermined pre-coding matrix;
- transmitting the first pre-coding signal from a first antenna at a first time and a first frequency;
- and
- transmitting the second pre-coding signal from a second antenna at the first time and the first frequency, wherein
- a second minimum distance between each signal point of the adjusted second modulation signal on an I-Q plane is shorter than a first minimum distance between each signal point of the adjusted first modulation signal on an I-Q plane.
Dependencies are inferred from the claim text.