Wireless transmission method, wireless transmission system, and transmission apparatus and reception apparatus of wireless transmission system

1. A wireless transmission system which transmits and receives a single carrier modulated signal between a transmitter and a receiver that are coupled through a wireless transmission path, wherein

the transmitter comprises a spectrum division filter bank that includes a Fourier transform unit converting the single carrier modulated signal to a frequency domain, a frequency allocation unit generating from the single carrier modulated signal in the frequency domain a plurality of sub-spectrum signals, each of which is arranged at a predetermined frequency position, and an inverse Fourier transform unit converting the sub-spectrum signals to time domain to produce a time domain signal,

the transmitter using the time domain signal subjects the plurality of sub-spectrum signals arranged in spectra to a direct spectrum division transmission, and

the receiver comprises a spectrum combination filter bank extracting the plurality of sub-spectrum signals from received signals arranged in spectra and subjected to the direct spectrum division transmission to combine the sub-spectrum signals into an original single carrier modulated signal.

2. The wireless transmission system according to claim 1 , wherein

the spectrum division filter bank further includes:

a plurality of spectrum division units dividing an output from the Fourier transform unit and outputting the plurality of sub-spectrum signals;

a plurality of frequency shift units shifting each of the plurality of sub-spectrum signals output from the plurality of spectrum division units to the predetermined frequency position;

an addition unit performing an addition of outputs from the plurality of frequency shift units, and arranging each of the outputs at the predetermined frequency position; and

wherein the inverse Fourier transform unit converts an output from the addition unit to time domain.

3. The wireless transmission system according to claim 1 , wherein

the spectrum division filter bank further includes:

a plurality of frequency shift units each shifting an output from the Fourier transform unit to the predetermined frequency position;

a plurality of spectrum division units dividing each output from the plurality of frequency shift units and outputting the plurality of sub-spectrum signals;

an addition unit performing an addition of outputs from the plurality of spectrum division units, and arranging each of the outputs at the predetermined frequency position; and

wherein the inverse Fourier transform unit converts an output from the addition unit to time domain.

4. The wireless transmission system according to claim 1 , wherein the spectrum combination filter bank includes:

a Fourier transform unit converting the received signals to frequency domain;

a plurality of spectrum extraction units dividing an output from the Fourier transform unit and extracting the plurality of sub-spectrum signals;

a plurality of frequency shift units shifting each of the plurality of sub-spectrum signals output from the plurality of spectrum extraction units to an original frequency position where each of the sub-spectrum signals is at before arranged to the predetermined frequency position;

an addition unit performing an addition of outputs from the plurality of frequency shift units, and combining the outputs at the original frequency position; and

an inverse Fourier transform unit converting an output from the addition unit to time domain.

5. The wireless transmission system according to claim 1 , wherein

the spectrum combination filter bank includes:

a Fourier transform unit converting the received signals to frequency domain;

a plurality of frequency shift units each shifting an output from the Fourier transform unit from the predetermined frequency position to an original frequency position where each of the sub-spectrum signals is at before arranged to the predetermined frequency position;

a plurality of spectrum extraction units dividing each output from the plurality of frequency shift units and extracting the plurality of sub-spectrum signals;

an addition unit performing an addition of outputs from the plurality of spectrum extraction units, and combining the outputs at the original frequency position; and

an inverse Fourier transform unit converting an output from the addition unit to time domain.

6. The wireless transmission system according to claim 1 , wherein the transmitter and the receiver transmit the plurality of sub-spectrum signals through respective wireless transmission paths.

7. The wireless transmission system according to claim 6 , wherein

the spectrum division filter bank includes:

a the Fourier transform unit converting the single carrier modulated signal to frequency domain;

a plurality of spectrum division units dividing an output from the Fourier transform unit and outputting the plurality of sub-spectrum signals;

a plurality of frequency shift units shifting each of the plurality of sub-spectrum signals output from the plurality of spectrum division units to the predetermined frequency position, and outputting each of the plurality of sub-spectrum signals arranged at the predetermined frequency position; and

a plurality of inverse Fourier transform units converting each output from the plurality of frequency shift units to time domain.

8. The wireless transmission system according to claim 6 , wherein

the spectrum division filter bank includes:

a the Fourier transform unit converting the single carrier modulated signal to frequency domain;

a plurality of frequency shift units each shifting an output from the Fourier transform unit to the predetermined frequency position;

a plurality of spectrum division units dividing each output from the plurality of frequency shift units and outputting each of the plurality of sub-spectrum signals arranged at the predetermined frequency position; and

a plurality of inverse Fourier transform units converting each output from the plurality of spectrum division units to time domain.

9. The wireless transmission system of any of claim 2 , 3 , 7 or 8 , wherein

the spectrum division units each multiply the single carrier modulated signal by more than one spectrum division weighting function BD k (ω) to generate N sub-spectrum signals Sb k (ω), where k represents a natural number from 1 to N, N represents the number of divided spectra and co represents a frequency.

10. The wireless transmission system according to claim 9 , wherein

an overall transfer function BT k (ω) being a product of the spectrum division weighting function BD k (ω) and the spectrum combination weighting function BC k (ω) is represented in an occupied spectrum of the single carrier modulated signal as follows:

Σ| BT k (ω) G (ω+ω k )|= A

where A represents a constant and ω k represents a value determined by the frequency allocation of the sub-spectrum signal.

11. The wireless transmission system according to claim 9 , wherein

the spectrum division weighting function BD k (ω) and the spectrum combination weighting function BC k (ω) making up a pair are both the same root roll-off function.

12. The wireless transmission system according to claim 9 , wherein

a product of a mean frequency spectrum F(ω) of the single carrier modulated signal and the spectrum division weighting function BD k (ω) satisfies

| F (ω) BD k (ω) G (ω+ω k )|=| BC k (ω)|

and the spectrum combination weighting function BC k (ω) is a root roll-off function.

13. The wireless transmission system according to claim 6 , wherein

the spectrum combination filter bank includes:

a plurality of Fourier transform units converting each of received signals transmitted through the plurality of wireless transmission paths to frequency domain;

a plurality of spectrum extraction units dividing each output from the plurality of Fourier transform units and extracting the plurality of sub-spectrum signals;

a plurality of frequency shift units shifting each of the plurality of sub-spectrum signals output from the plurality of spectrum extraction units to an original frequency position where each of the sub-spectrum signals is at before assigned to the predetermined frequency position;

an addition unit performing an addition of outputs from the plurality of frequency shift units, and combining the outputs at the original frequency position; and

an inverse Fourier transform unit converting an output from the addition unit to time domain.

14. The wireless transmission system according to claim 6 , wherein

the spectrum combination filter bank includes:

a plurality of Fourier transform units converting each of received signals transmitted through the plurality of wireless transmission paths to frequency domain;

a plurality of frequency shift units shifting each output from the plurality of Fourier transform units from the predetermined frequency position to an original frequency position where each of the sub-spectrum signals is at before assigned to the predetermined frequency position;

a plurality of spectrum extraction units dividing each output from the plurality of frequency shift units and extracting the plurality of sub-spectrum signals;

an addition unit performing an addition of outputs from the plurality of spectrum extraction units, and combining the outputs at the original frequency position; and

an inverse Fourier transform unit converting an output from the addition unit to time domain.

15. The wireless transmission system of any of claim 4 , 5 , 13 or 14 , wherein

the spectrum extraction units each multiply N sub-spectrum signals Sb k (ω), contained in the received signals by a spectrum combination weighting function BC k (ω) corresponding to a transfer function G(ω) between the transmitter and the receiver and the spectrum division weighting function BD k (ω).

16. The wireless transmission system according to claim 15 , wherein

a product of a mean frequency spectrum F(ω) of the single carrier modulated signal and the spectrum division weighting function BD k (ω) satisfies

| F (ω) BD k (ω) G (ω+ω k )|=| BC k (ω)|

and the spectrum combination weighting function BC k (ω) is a root roll-off function.

17. A wireless transmission method which transmits and receives a single carrier modulated signal between a transmitter and a receiver that are coupled through a wireless transmission path, wherein

the transmitter uses a spectrum division filter bank that performs a Fourier transform to convert the single carrier modulated signal to a frequency domain, that performs frequency allocation to generate from the single carrier modulated signal in the frequency domain a plurality of sub-spectrum signals, each of which is arranged at a predetermined frequency position, and that performs an inverse Fourier transform to convert the sub-spectrum signals to time domain to produce a time domain signal,

the transmitter uses the time domain signal to subject the plurality of sub-spectrum signals arranged in spectra to a direct spectrum division transmission, and

the receiver uses a spectrum combination filter bank to extract the plurality of sub-spectrum signals from received signals arranged in spectra and subjected to the direct spectrum division transmission to combine the sub-spectrum signals into an original single carrier modulated signal, which is in turn subjected to demodulation processing.

18. The wireless transmission method according to claim 17 , wherein

the spectrum division filter bank

divides the frequency domain single carrier modulated signal and outputs the plurality of sub-spectrum signals;

shifts each of the plurality of sub-spectrum signals to the predetermined frequency position;

performs an addition of the shifted plurality of sub-spectrum signals arranged at the predetermined frequency position; and

converts the added shifted plurality of sub-spectrum signals arranged at the predetermined frequency position to time domain by performing an inverse Fourier transform.

19. The wireless transmission method according to claim 17 , wherein

the spectrum division filter bank

shifts the frequency domain signal carrier modulated signal to a plurality of frequency shifted signals;

divides each of the plurality of frequency shifted signals and uses the divided signals to output the plurality of sub-spectrum signals;

performs an addition of the plurality of sub-spectrum signals, and arranges the resulting sum at the predetermined frequency; and

converts the resulting sum to time domain by performing an inverse Fourier transform.

20. The wireless transmission method according to claim 17 , wherein

the spectrum combination filter bank

converts the received signals to frequency domain by a Fourier transform unit;

divides an output from the Fourier transform unit and extracts the plurality of sub-spectrum signals by a plurality of spectrum extraction units;

shifts each of the plurality of sub-spectrum signals output from the plurality of spectrum extraction units to an original frequency position where each of the sub-spectrum signals is at before assigned to the predetermined frequency position by a plurality of frequency shift units;

performs an addition of outputs from the plurality of frequency shift units, and combines the outputs at the original frequency position by an addition unit; and

converts an output from the addition unit to time domain by an inverse Fourier transform unit.

21. The wireless transmission method according to claim 17 , wherein

the spectrum combination filter bank

converts the received signals to frequency domain by a Fourier transform unit;

shifts an output from the Fourier transform unit from the predetermined frequency position to an original frequency position where each of the sub-spectrum signals is at before assigned to the predetermined frequency position by each of a plurality of frequency shift units;

divides each output from the plurality of frequency shift units and extracts the plurality of sub-spectrum signals by a plurality of spectrum extraction units;

performs an addition of outputs from the plurality of spectrum extraction units, and combines the outputs at the original frequency position by an addition unit; and

converts an output from the addition unit to time domain by an inverse Fourier transform unit.

22. The wireless transmission method according to claim 17 , wherein

the transmitter and the receiver transmit the plurality of sub-spectrum signals through respective wireless transmission paths.

23. The wireless transmission method according to claim 22 , wherein

the spectrum division filter bank

converts the single carrier modulated signal to frequency domain by a Fourier transform unit;

divides an output from the Fourier transform unit and outputs the plurality of sub-spectrum signals by a plurality of spectrum division units;

shifts each of the plurality of sub-spectrum signals to the predetermined frequency position, and outputs each of the plurality of sub-spectrum signals arranged at the predetermined frequency position by a plurality of frequency shift units; and

converts each output from the plurality of frequency shift units to time domain by a plurality of inverse Fourier transform units.

24. The wireless transmission method according to claim 22 , wherein

the spectrum division filter bank

converts the single carrier modulated signal to frequency domain by a Fourier transform unit;

shifts an output from the Fourier transform unit to the predetermined frequency position by each of a plurality of frequency shift units;

divides each output from the plurality of frequency shift units and outputs each of the plurality of sub-spectrum signals arranged at the predetermined frequency position by a plurality of spectrum division units; and

converts each output from the plurality of spectrum division units to time domain by a plurality of inverse Fourier transform units.

25. The wireless transmission method according to claim 22 , wherein

the spectrum combination filter bank

converts each of received signals transmitted through the plurality of wireless transmission paths to frequency domain by a plurality of Fourier transform units;

divides an output from the Fourier transform unit and extracts the plurality of sub-spectrum signals by a plurality of spectrum extraction units;

shifts each of the plurality of sub-spectrum signals output from the plurality of spectrum extraction units to an original frequency position where each of the sub-spectrum signals is at before assigned to the predetermined frequency position by a plurality of frequency shift units;

performs an addition of outputs from the plurality of frequency shift units, and combines the outputs at the original frequency position by an addition unit; and

converts an output from the addition unit to time domain by an inverse Fourier transform unit.

26. The wireless transmission method according to claim 22 , wherein

the spectrum combination filter bank

converts each of received signals transmitted through the plurality of wireless transmission paths to frequency domain by a plurality of Fourier transform units;

shifts each output from the plurality of Fourier transform units from the predetermined frequency position to an original frequency position where each of the sub-spectrum signals is at before assigned to the predetermined frequency position by a plurality of frequency shift units;

divides each output from the plurality of frequency shift units and extracts the plurality of sub-spectrum signals by a plurality of spectrum extraction units;

performs an addition of outputs from the plurality of spectrum extraction units, and combines the outputs at the original frequency position by an addition unit; and

converts an output from the addition unit to time domain by an inverse Fourier transform unit.