RADIO TRANSMISSION SYSTEM, RADIO COMMUNICATION APPARATUS, AND RADIO TRANSMISSION METHOD

• US 20110098010A1
• Filed: 09/24/2010
• Published: 04/28/2011
• Est. Priority Date: 10/22/2009
• Status: Active Grant

• Current Assignee: Sony Corporation (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.)
• Inventors: MIHOTA, Norihito
• Granted Patent: US 8,781,412 B2
• Time in Patent Office: Days
• US Class Current: 455/101
• CPC Class Codes: H04B 7/0413 MIMO systems
• CPC Class Codes: H04L 27/02 Amplitude-modulated carrier systems, e.g. using on-off keying; Single sideband or vestigial sideband modulation H04L27/32 takes precedence
• CPC Class Codes: H04L 27/18 Phase-modulated carrier systems, i.e. using phase-shift keying H04L27/32 takes precedence
• CPC Class Codes: H04W 52/262 taking into account adaptive modulation and coding [AMC] scheme AMC per se H04L1/0001

Abstract

A radio transmission system includes: antenna pairs, each antenna pair being a combination of a transmitting antenna and a receiving antenna in one-to-one correspondence. A radio signal from the transmitting antenna in one of the antenna pairs reaches the receiving antenna of the one antenna pair as a desired wave directly, and a radio signal from the transmitting antenna of another antenna pair different from the one antenna pair reaches the receiving antenna of the one antenna pair as an unnecessary wave directly. A transfer characteristic correction section which performs a correction operation based on the transfer characteristic of a transmission space between the transmitting antenna and the receiving antenna for a transmission-target signal corresponding to the transmitting antenna, and a modulation functional section which modulates a carrier signal with a corrected signal after having been corrected by the transfer characteristic correction section and transmits the modulated carrier signal from the corresponding transmitting antenna, are provided in correspondence with each antenna pair.

Claims

1. A radio transmission system comprising:

a plurality of antenna pairs, each antenna pair being a combination of a transmitting antenna and a receiving antenna in one-to-one correspondence,

wherein the system is configured such that a radio signal from the transmitting antenna in one of the plurality of antenna pairs reaches the receiving antenna of the one antenna pair as a desired wave directly, and a radio signal from the transmitting antenna of another antenna pair different from the one antenna pair reaches the receiving antenna of the one antenna pair as an unnecessary wave directly,

a transfer characteristic correction section and a modulation functional section are provided in correspondence with each antenna pair,

the transfer characteristic correction section performs a correction operation based on the transfer characteristic of a transmission space between the transmitting antenna and the receiving antenna for a transmission-target signal corresponding to the transmitting antenna, and

the modulation functional section modulates a carrier signal with a corrected signal after having been corrected by the transfer characteristic correction section and transmits the modulated carrier signal from the corresponding transmitting antenna.

2. The radio transmission system according to claim 1,

wherein a path difference which is the difference between the inter-antenna distance of the desired wave and the inter-antenna distance of the unnecessary wave between the transmitting antenna and the receiving antenna is set such that each element of the desired wave of a matrix prescribing the transfer characteristic are expressed only by a real term, and each element of the unnecessary wave of the matrix prescribing the transfer characteristic is expressed only by a real term or an imaginary term.

3. The radio transmission system according to claim 1 or 2,

wherein, when the wavelength of the carrier signal used in the modulation functional section is λ

c, and the phase characteristics depending on the directionality of antennas are zero, the path difference which is the difference between the inter-antenna distance of the desired wave and the inter-antenna distance of the unnecessary wave between the transmitting antenna and the receiving antenna is set to (n/2+¼

)λ

c (where n is a positive integer of 0 or equal to or greater than

     1), and

when the radiation angle from the transmitting antenna of the one antenna pair to the receiving antenna of the one antenna pair is θ

1, the radiation angle from the transmitting antenna of another antenna pair to the receiving antenna of the one antenna pair is θ

2, and the phase characteristics depending on the directionality of the antennas are φ

a(θ

1) and φ

a(θ

2), the path difference is corrected by −

(φ

a(θ

2)−

φ

a(θ

1))/π

)λ

c.

4. The radio transmission system according to claim 1 or 2,

wherein, when the wavelength of the carrier signal used in the modulation functional section is λ

c, and the phase characteristics depending on the directionality of antennas are zero, the path difference which is the difference between the inter-antenna distance of the desired wave and the inter-antenna distance of the unnecessary wave between the transmitting antenna and the receiving antenna is set to (n/2)λ

c (where n is a positive integer equal to or greater than

     1), and

when the radiation angle from the transmitting antenna of the one antenna pair to the receiving antenna of the one antenna pair is θ

1, the radiation angle from the transmitting antenna of another antenna pair to the receiving antenna of the one antenna pair is θ

2, and the phase characteristics depending on the directionality of the antennas are φ

a(θ

1) and φ

a(θ

2), the path difference is corrected by −

(φ

a(θ

2)−

φ

a(θ

1))/π

)λ

c.

5. The radio transmission system according to claim 2,

wherein the path difference is set such that each element of the unnecessary wave of the matrix prescribing the transfer characteristic is expressed only by an imaginary term.

6. The radio transmission system according to claim 2,

wherein the path difference is set such that each element of the unnecessary wave of the matrix prescribing the transfer characteristic is expressed only by a real term.

7. The radio transmission system according to claim 1 or 2,

wherein, with regard to each of a plurality of transmission-target signals, the transfer characteristic correction section performs only a real term-related correction operation for a desired signal and only an imaginary term-related correction operation for an unnecessary signal, and supplies a real term-related corrected signal for the desired signal and an imaginary term-related corrected signal for the unnecessary signal in a pair to the modulation functional section, and

with regard to each of the plurality of transmission-target signals, the modulation functional section quadrature-modulates for the real term-related corrected signal for the desired signal and the imaginary term-related corrected signal for the unnecessary signal supplied in a pair from the transfer characteristic correction section.

8. The radio transmission system according to claim 1 or 2,

wherein, with regard to each of a plurality of transmission-target signals, the transfer characteristic correction section performs only a real term-related correction operation for a desired signal and also only a real term-related correction operation for an unnecessary signal, adds a real term-related corrected signal for the desired signal and a real term-related corrected signal for the unnecessary signal, and supplies the added signal to the modulation functional section, and

with regard to each of the plurality of transmission-target signals, the modulation functional section modulates the added signal of the real term-related corrected signal for the desired signal and the real term-related corrected signal for the unnecessary signal supplied from the transfer characteristic correction section.

9. The radio transmission system according to any one of claims 3, 5, and 7,

wherein the modulation functional section uses a scheme for modulating only amplitude for part of the systems of a plurality of transmission-target signals in the antenna pairs and a scheme other than the scheme for modulating only amplitude for the remaining systems, and

the radio transmission system further comprises:

a demodulation functional section which, with regard to each of the plurality of transmission-target signals, creates a carrier signal for demodulation synchronized with a carrier signal for modulation through injection locking on the basis of a received signal, and demodulates a received modulated signal through frequency conversion with the carrier signal for demodulation; and

a phase-shift section which, with regard to the systems using the scheme other than the scheme of modulating amplitude, shifts the phase of the carrier signal for demodulation and supplies the phase-shifted carrier signal to the corresponding demodulation functional section.

10. The radio transmission system according to any one of claims 3, 5, and 7,

wherein the modulation functional section uses a scheme of modulating only amplitude for part of the systems of a plurality of transmission-target signals in the antenna pairs and a scheme other than the scheme of modulating only amplitude for the remaining systems, and

the radio transmission system further comprises a demodulation functional section which, with regard to the systems using the scheme of modulating only amplitude within the plurality of transmission-target signals, creates a carrier signal for demodulation synchronized with a carrier signal for modulation through injection locking on the basis of a received signal and demodulates a received modulated signal through frequency conversion with the carrier signal for demodulation, and with regard to the systems not using the injection locking scheme, demodulates the received modulated signal through frequency conversion with the carrier signal for demodulation created by the systems using the injection locking scheme.

11. The radio transmission system according to any one of claims 4, 6, and 8,

wherein the modulation functional section uses a scheme of modulating only amplitude for part of the systems of a plurality of transmission-target signals in the antenna pairs and uses a scheme other than the scheme of modulating only amplitude for the remaining systems,

the reception-side radio communication apparatus includes

a demodulation functional section which, with regard to each of the plurality of transmission-target signals, creates a carrier signal for demodulation synchronized with a carrier signal for modulation through injection locking on the basis of a received signal and demodulates a received modulated signal through frequency conversion with the carrier signal for demodulation, and

a sign setting section which, with regard to the systems using the scheme other than the scheme of modulating amplitude, sets the sign of an output signal output from the demodulation functional section.

12. The radio transmission system according to any one of claims 4, 6, and 8,

wherein the modulation functional section uses a scheme of modulating only amplitude for part of the systems of a plurality of transmission-target signals in the antenna pairs and uses a scheme other than the scheme of modulating only amplitude for the remaining systems, and

the reception-side radio communication apparatus includes

a demodulation functional section which, with regard to the systems using the scheme of modulating only amplitude within the plurality of transmission-target signals, creates a carrier signal for demodulation synchronized with a carrier signal for modulation through injection locking on the basis of a received signal and demodulates a received modulated signal through frequency conversion with the carrier signal for demodulation, and with regard to the systems not using the injection locking scheme, demodulates the received modulated signal on the basis of the carrier signal for demodulation created by the systems using the injection locking scheme through frequency conversion.

13. The radio transmission system according to any one of claims 4, 6, and 8,

wherein the modulation functional section uses a scheme of modulating only amplitude for all the systems of a plurality of transmission-target signals, and

the reception-side radio communication apparatus includes

a demodulation functional section which, with regard to each of the plurality of transmission-target signals, creates a carrier signal for demodulation synchronized with a carrier signal for modulation through injection locking on the basis of a received signal and demodulates a received modulated signal through frequency conversion with the carrier signal for demodulation.

14. The radio transmission system according to any one of claims 4, 6, and 8,

wherein the modulation functional section uses a scheme of modulating only amplitude for all the systems of a plurality of transmission-target signals, and

the reception-side radio communication apparatus includes

a demodulation functional section which mixes a system in which a carrier signal for demodulation synchronized with a carrier signal for modulation is created through injection locking on the basis of a received signal and a received modulated signal is demodulated through frequency conversion with the carrier signal for demodulation and a system in which the received modulated signal is demodulated through frequency conversion on the basis of the carrier signal for demodulation created by injection locking.

15. The radio transmission system according to any one of claims 4, 6, and 8,

wherein the modulation functional section uses a scheme of modulating only amplitude for all the systems of a plurality of transmission-target signals, and

the reception-side radio communication apparatus includes

a demodulation functional section which performs envelope detection or square-law detection for a received modulated signal.

16. The radio transmission system according to any one of claims 1 to 15,

wherein the frequency of a carrier signal which is used in the modulation functional section is in common to all the systems.

17. A radio communication apparatus for a system which includes a plurality of antenna pairs, each antenna being a combination of a transmitting antenna and a receiving antenna in one-to-one correspondence, the apparatus comprising:

a transfer characteristic correction section which, with regard to each of transmission-target signals corresponding to the transmitting antennas configured such that a radio signal from the transmitting antenna of one of the plurality of antenna pairs reaches the receiving antenna of the one antenna pair as a desired wave directly, and a radio signal from the transmitting antenna of another antenna pair different from the one antenna pair reaches the receiving antenna of the antenna pair as an unnecessary wave directly, performs a correction operation based on the transfer characteristic of a transmission space between the transmitting antenna and the receiving antenna.

18. The radio communication apparatus according to claim 17,

wherein a modulation functional section is provided in correspondence with each antenna pair to modulate a carrier signal with a corrected signal after having been corrected by the transfer characteristic correction section and to transmit the modulated signal from the corresponding transmitting antenna.

19. The radio communication apparatus according to claim 18,

wherein, with regard to each of a plurality of transmission-target signals, the transfer characteristic correction section performs only a real term-related correction operation for a desired signal and only an imaginary term-related correction operation for an unnecessary signal, and supplies a real term-related corrected signal for the desired signal and an imaginary term-related corrected signal for the unnecessary signal in pair to the modulation functional section, and with regard to each of the plurality of transmission-target signals, the modulation functional section performs quadrature modulation for the real term-related corrected signal for the desired signal and the imaginary term-related corrected signal for the unnecessary signal supplied in pair from the transfer characteristic correction section, and

with regard to each of the plurality of the transmission-target signals, the transfer characteristic correction section performs only a real term-related correction operation for the desired signal and also only a real term-related correction operation for the unnecessary signal, adds a real term-related corrected signal for the desired signal and a real term-related corrected signal for the unnecessary signal, and supplies the added signal to the modulation functional section, and with regard to each of the plurality of transmission-target signals, the modulation functional section modulates the added signal of the real term-related corrected signal for the desired signal and the real term-related corrected signal for the unnecessary signal supplied from the transfer characteristic correction section.

20. A radio transmission method comprising the steps of:

providing a plurality of antenna pairs, each antenna pair being a combination of a transmitting antenna and a receiving antenna in one-to-one correspondence;

allowing radio transmission to be performed through space division multiplex such that a radio signal from the transmitting antenna of one of the plurality of antenna pairs reaches the receiving antenna of the one antenna pair as a desired wave directly and a radio signal from the transmitting antenna of another antenna pair different from the one antenna pair reaches the receiving antenna of the one antenna pair as an unnecessary wave directly; and

performing a correction operation with regard to each of the transmission-target signals corresponding to the transmitting antennas based on the transfer characteristic of a transmission space between the transmitting antenna and the receiving antenna is performed, modulating a carrier signal with a corrected signal after correction, and transmitting a modulated signal from the corresponding transmitting antenna.