CLAIMS
1. A wireless transmitter comprising:
a phase rotation sequence generation unit to generate, on a basis of input transmit bits, a phase rotation sequence in which a frequency response has a bandwidth;
an up-sampling unit to change a sample rate of the phase rotation sequence and further replicate the phase rotation sequence; and
a frequency shift unit to shift, by a specified amount of shift on a frequency axis, a frequency component of the phase rotation sequence acquired from the up-sampling unit.
2. The wireless transmitter according to claim 1, wherein
the phase rotation sequence generation unit generates the
phase rotation sequence, using a first phase rotation sequence and a second phase rotation sequence whose frequency component changes with time, the first phase rotation sequence being a frequency modulated signal whose frequency is selected on the basis of the transmit bits.
3. The wireless transmitter according to claim 2, wherein
the phase rotation sequence generation unit generates the
phase rotation sequence, using a plurality of the first phase rotation sequences that has a sequence length shorter than a sequence length of the second phase rotation sequence.
4. The wireless transmitter according to claim 3, wherein
the phase rotation sequence generation unit generates the
first phase rotation sequence, using a data signal and a known signal.
5. The wireless transmitter according to any one of claims 1
to 4, wherein
the magnitude of the specified amount of shift is

different from the magnitude of an amount of shift set in another wireless transmitter, and
the frequency shift unit shifts the frequency component of the phase rotation sequence on the frequency axis on the basis of the specified amount of shift, to thereby allow the wireless transmitter to transmit a signal such that the transmitted signal does not overlap a signal transmitted from the other wireless transmitter on the frequency axis.
6. The wireless transmitter according to any one of claims 2
to 4, wherein
the phase rotation sequence generation unit generates the phase rotation sequence, using the second phase rotation sequence having cross correlation with another wireless transmitter, the cross correlation being lower than a specified threshold.
7. A wireless receiver that receives a signal transmitted
from the wireless transmitter according to any one of claims 1
to 6, the wireless receiver comprising:
an equalization processing unit to correct distortion received on a wireless transmission path;
a sequence multiplication unit to multiply a signal corrected by the equalization processing unit, by a complex conjugate of a second phase rotation sequence that is used when the wireless transmitter generates a phase rotation sequence;
a discrete Fourier transform unit to perform a discrete Fourier transform on a result of processing by the sequence multiplication unit and obtain a frequency domain signal;
a determination unit to perform signal determination on the basis of the frequency domain signal; and
an interference measurement unit to calculate a measured interference value with respect to the frequency domain signal

on the basis of a signal of a frequency other than a frequency including a transmit signal component.
8. The wireless receiver according to claim 7, wherein
the interference measurement unit calculates the measured interference value when the transmit signal component is a known signal or a data signal.
9. The wireless receiver according to claim 7 or 8, further
comprising:
a reverse frequency shift unit to remove, from the signal received from the wireless transmitter, an amount of shift of a frequency component shifted by the wireless transmitter; and
a synthesis unit to synthesize the phase rotation sequence replicated by the wireless transmitter, wherein
the sequence multiplication unit multiplies the synthesized signal by the complex conjugate.
10. A wireless communication system comprising:
the wireless transmitter according to claim 1; and the wireless receiver according to claim 7, wherein the wireless transmitter and the wireless receiver each set an amount of frequency shift and a type of a phase rotation sequence on the basis of a transmission timing of the wireless transmitter and an amount of interference in the wireless receiver.
11. The wireless communication system according to claim 10,
further comprising
a repeater including the wireless transmitter and the wireless receiver, wherein
the repeater relays a signal received from another wireless transmitter to another wireless receiver, such that the wireless transmitter and the wireless receiver that are

not capable of transmitting and receiving a signal directly to and from each other establish communication therebetween via relaying by the repeater.
12. The wireless communication system according to claim 11, wherein a transmission timing of the wireless transmitter and the repeater and a reception timing of the wireless receiver and the repeater are controlled by time division duplex, and the amount of frequency shift and the type of the phase rotation sequence of the wireless transmitter, the wireless receiver, and the repeater are set on the basis of the transmission timing and the reception timing controlled by the time division duplex.