RADIO COMMUNICATION METHOD, RADIO TRANSMISSION APPARATUS AND RECEIVING APPARATUS

• US 20080227389A1
• Filed: 09/12/2007
• Published: 09/18/2008
• Est. Priority Date: 03/15/2007
• Status: Active Grant

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Sakata, Ren, Deguchi, Noritaka, Ban, Koichiro, Akita, Koji
• Granted Patent: US 8,385,851 B2
• Time in Patent Office: Days
• US Class Current: 455/39
• CPC Class Codes: H04B 7/12 Frequency diversity
• CPC Class Codes: H04L 1/04 using frequency diversity
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A radio communication method including, generating a first transmit RF signal and a second transmit RF signal from a data signal to be transmitted, each of the first and second transmit RF signals having a power spectrum in symmetric shape in the frequency domain, transmitting the first transmit RF signal and the second transmit RF signal at a different time, receiving the first transmit RF signal and the second transmit RF signal to generate a first received RF signal and a second received RF signal, and reproducing the data signal from the first received RF signal and the second received RF signal.

Claims

1. A radio communication method comprising:

generating a first transmit RF signal and a second transmit RF signal from a data signal to be transmitted, the first transmit RF signal and second transmit RF signal respectively having a power spectrum in symmetric shape in the frequency domain;

transmitting the first transmit RF signal and the second transmit RF signal at a different time;

receiving the first transmit RF signal and the second transmit RF signal to generate a first received RF signal and a second received RF signal; and

reproducing the data signal from the first received RF signal and the second received RF signal.

2. A transmission apparatus comprising:

a transmitter configured to generate a first transmit RF signal and a second transmit RF signal from a data signal to be transmitted, and to output them at a different time, the first transmit RF signal and the second transmit RF signal respectively having a power spectrum in a symmetric shape in the frequency domain; and

a transmit antenna to transmit the first transmit RF signal and the second transmit RF signal.

3. The apparatus according to claim 2, wherein the first transmit RF signal and the second transmit RF signal have different center frequencies.

4. The apparatus according to claim 2, wherein the first transmit RF signal has a transmittable lowest frequency, and the second transmit RF signal has a transmittable highest frequency.

5. The apparatus according to claim 2, wherein the transmitter comprises a modulator to modulate the data signal to generate a first transmit baseband signal which has a first power spectrum, a first computing unit configured to subject the first transmit baseband signal to a first computation to generate a second transmit baseband signal which has a power spectrum forming a symmetric shape with respect to the first power spectrum in the frequency domain, an RF transmission unit configured to subject the first transmit baseband signal and the second transmit baseband signal to an RF process to generate the first transmit RF signal and the second transmit RF signal.

6. The apparatus according to claim 5, wherein the first transmit baseband signal is a complex number signal having a real part and an imaginary part, and the computation is done by multiplying either one of the real part and the imaginary part by −

1.

7. The apparatus according to claim 5, wherein the first transmit baseband signal is a complex number signal having a real part and an imaginary part, and the computation replaces the real part with the imaginary part.

8. The apparatus according to claim 2, wherein the transmitter comprises a modulator to modulate the transmit data signal to generate a modulated signal, a first frequency converter to subject the modulated signal to a frequency conversion in a first frequency shift amount and a first frequency shift direction to generate a first transmit baseband signal, a first computing unit configured to subject the first transmit baseband signal to a first computation to generate a second transmit baseband signal which has a power spectrum forming a symmetric shape with respect to the first power spectrum in the frequency domain, and an RF transmission unit configured to subject the first transmit baseband signal and the second transmit baseband signal to an RF process to generate the first transmit RF signal and the second transmit RF signal.

9. The apparatus according to claim 8, wherein the first transmit baseband signal is a complex number signal having a real part and an imaginary part, and the computation multiplies either one of the real part and the imaginary part by −

1.

10. The apparatus according to claim 8, wherein the first transmit baseband signal is a complex number signal having a real part and an imaginary part, and the computation replaces the real part with the imaginary part.

11. The apparatus according to claim 8, wherein the frequency converter comprises a first converter to convert the modulated signal into a first signal spectrum in a frequency domain, and a second converter to convert the center frequency of the first signal spectrum and convert it into a time wave to generate the first transmit baseband signal.

12. The apparatus according to claim 11, wherein the first converter is a DFT unit, and the second converter is an IFFT unit.

13. A radio receiving apparatus comprising:

a receive antenna to receive the first transmit RF signal and the second transmit RF signal transmitted from the apparatus according to claim 5 to obtain a first received RF signal and a second received RF signal;

an RF reception unit configured to subject the first received RF signal and the second received RF signal to an RF process to generate a first received baseband signal and a second received baseband signal;

a channel equalizer to subject the first received baseband signal and the second received baseband signal to channel equalization to obtain a first equalized baseband signal and a second equalized baseband signal;

a second computing unit configured to subject the second equalized baseband signal to a second computation;

a combiner to combine the second equalized baseband signal which has undergone the second computation and the first equalized baseband signal to obtain a combined baseband signal; and

a demodulator to demodulate the combined baseband signal to reproduce the data signal.

14. A radio receiving apparatus comprising:

a receive antenna to receive the first transmit RF signal and the second transmit RF signal transmitted from the apparatus according to claim 8 to obtain a first received RF signal and a second received RF signal;

an RF reception unit configured to subject the first received RF signal and the second received RF signal to an RF process to generate a first received baseband signal and a second received baseband signal;

a channel equalizer to subject the first received baseband signal and the second received baseband signal to channel equalization to obtain a first equalized baseband signal and a second equalized baseband signal;

a second computing unit configured to subject the second equalized baseband signal to a second computation;

a combiner to combine the second equalized baseband signal which has undergone the second computation and the first equalized baseband signal to obtain a combined baseband signal;

a second frequency converter to subject the combined baseband signal to a frequency conversion in the first frequency shift amount and a second frequency shift direction which is the opposite of the first frequency shift direction to generate a converted baseband signal; and

a demodulator to demodulate the converted baseband signal to reproduce the data signal.