POLARIZATION-ANGLE-DIVISION DIVERSITY WIRELESS TRANSMITTER, WIRELESS RECEIVER, AND WIRELESS COMMUNICATION SYSTEM

• US 20130336417A1
• Filed: 03/09/2011
• Published: 12/19/2013
• Est. Priority Date: 03/09/2011
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Takei, Ken
• Granted Patent: US 9,407,349 B2
• Time in Patent Office: Days
• US Class Current: 375/267
• CPC Class Codes: H04B 7/0613 using simultaneous transmission H04B7/0686 takes precedence
• CPC Class Codes: H04B 7/08 at the receiving station
• CPC Class Codes: H04B 7/0894 using different delays between antennas
• CPC Class Codes: H04B 7/10 Polarisation diversity; Directional diversity
• CPC Class Codes: H04L 27/18 Phase-modulated carrier systems, i.e. using phase-shift keying H04L27/32 takes precedence

Abstract

A wireless transmitter has a modulator modulating an information signal of a frequency f1 by a carrier wave of a frequency f2 to output a first modulated signal, a transmitting antenna transmitting the first modulated signal using a linearly polarized wave, and a motor rotating the transmitting antenna at a frequency f3 to rotate the outgoing linearly polarized wave at the frequency f3 thereby multiplexing the first modulated signal with a linearly polarized wave component and a horizontally polarized wave component, the two components being independent of each other. A wireless receiver has diversity receiving antennas receiving the signal on a plurality of polarization planes to obtain a plurality of input signals; a path difference phase shifter compensating each of the input signals for the phase shift stemming from path differences, and a composer composing the corrected received signals.

Claims

1-4. -4. (canceled)

5. A polarization-angle-division diversity wireless transmitter comprising:

a first modulating unit modulating an information signal having a first frequency by a second frequency to output a first modulated signal; and

an electromagnetic wave transmitting unit transmitting the first modulated signal using two independent polarized waves and multiplies the polarized waves by a third frequency,

wherein the electromagnetic wave transmission means includes;

a second modulating unit modulating the first modulated signal by the third frequency to obtain a first output signal;

a first transmitting antenna which transmits the first output signal using a first polarized wave;

a phase shifting unit shifting a phase of the third frequency by a predetermined angle;

a third modulating unit modulating the first modulated signal by the shifted third frequency to obtain a second output signal; and

a second transmitting antenna which transmits the second output signal using a second polarized wave,

wherein the first transmitting antenna transmits a circularly polarized wave, and

wherein the second transmitting antenna transmits a circularly polarized wave rotating in the direction opposite to a direction of the first transmitting antenna.

6. The polarization-angle-division diversity wireless transmitter according to claim 5,

wherein the first frequency is set to be lower than the second frequency and the third frequency, and the second frequency is set to be higher than the third frequency.

7. A polarization-angle-division diversity wireless transmitter comprising:

a first modulating unit modulating an information signal having a first frequency by a second frequency to output a first modulated signal;

a fourth modulating unit modulating the information signal by a fourth frequency slightly different from the second frequency to output a fourth modulated signal;

a first composing unit composing the first modulated signal and the fourth modulated signal and further performing modulation by a third frequency generated from the difference between the second frequency and the fourth frequency to output a first output signal;

a second composing unit composing the first modulated signal and an inversion signal of the fourth modulated signal and further performing modulation by the third frequency generated from the difference between the second frequency and the inverted fourth frequency to output a second output signal;

a first transmitting antenna which transmits the first output signal using a first polarized wave; and

a second transmitting antenna which transmits the second output signal using a second polarized wave.

8. The polarization-angle-division diversity wireless transmitter according to claim 7,

wherein the first transmitting antenna transmits a linearly polarized wave, and

wherein the second transmitting antenna is set up at an angle between 85 and 95 degrees with the first transmitting antenna and transmits a linearly polarized wave.

9. The polarization-angle-division diversity wireless transmitter according to claim 7,

wherein the first transmitting antenna transmits a circularly polarized wave, and

wherein the second transmitting antenna transmits a circularly polarized wave rotating in the direction opposite to a direction of the first transmitting antenna.

10. The polarization-angle-division diversity wireless transmitter according to claim 7,

wherein the first frequency is set to be lower than the second frequency, the fourth frequency, and the third frequency;

and the second frequency and the fourth frequency are set to be higher than the third frequency.

14. A polarization-angle-division diversity wireless receiver for receiving an electromagnetic wave transmitted from the polarization-angle-division diversity wireless transmitter according to claim 7, the polarization-angle-division diversity wireless receiver comprising:

a first receiving antenna which receives the first polarized wave from the polarization-angle-division diversity wireless transmitter to obtain a first input signal;

a second receiving antenna which receives the second polarized wave from the polarization-angle-division diversity wireless transmitter to obtain a second input signal;

a first rotational frequency detecting unit blocking frequencies at least twice as high as the third frequency in the first signal to generate a first received signal;

a second rotational frequency detecting unit blocking frequencies at least twice as high as the third frequency in the second input signal to generate a second received signal; and

a multi-delay composing unit delaying and composing the first received signal and the second received signal.

15. The polarization-angle-division diversity wireless transmitter according to claim 14,

wherein the first receiving antenna receives a circularly polarized wave, and

wherein the second receiving antenna receives a circularly polarized wave rotating in the direction opposite to a direction of the first receiving antenna.

11. A polarization-angle-division diversity wireless receiver for receiving an electromagnetic wave transmitted from a polarization-angle-division diversity wireless transmitter including:

a first modulating unit modulating an information signal having a first frequency by a second frequency to output a first modulated signal; and

an electromagnetic wave transmitting unit transmitting the first modulated signal using two independent polarized waves and multiplying the polarized waves by a third frequency,

the polarization-angle-division diversity wireless receiver further comprising;

a plurality of antennas which receive the electromagnetic wave from the polarization-angle-division diversity wireless transmitter on a plurality of polarization planes to obtain a plurality of input signals;

a plurality of signal correcting unit correcting the input signals for phase shifts caused by path differences so as to generate a plurality of received signals, respectively; and

a composing unit composing the plurality of received signals.

12. A polarization-angle-division diversity wireless receiver for receiving an electromagnetic wave transmitted from a polarization-angle-division diversity wireless transmitter including:

a first modulating unit modulating an information signal having a first frequency by a second frequency to output a first modulated signal; and

an electromagnetic wave transmitting unit transmitting the first modulated signal using two independent polarized waves and multiplying the polarized waves by a third frequency,

wherein the electromagnetic wave transmission means includes;

a second modulating unit modulating the first modulated signal by the third frequency to obtain a first output signal;

a first transmitting antenna which transmits the first output signal using a first polarized wave;

a phase shifting unit shifting a phase of the third frequency by a predetermined angle;

a third modulating unit modulating the first modulated signal by the shifted third frequency to obtain a second output signal; and

a second transmitting antenna which transmits the second output signal using a second polarized wave,

the polarization-angle-division diversity wireless receiver further comprising;

a first receiving antenna which receives the first polarized wave from the polarization-angle-division diversity wireless transmitter to obtain a first input signal;

a second receiving antenna which receives the second polarized wave from the polarization-angle-division diversity wireless transmitter to obtain a second input signal;

a first rotational frequency detecting unit blocking frequencies at least twice as high as the third frequency in the first signal to generate a first received signal;

a second rotational frequency detecting unit blocking frequencies at least twice as high as the third frequency in the second input signal to generate a second received signal; and

a multi-delay composing unit delaying and composing the first received signal and the second received signal.

13. The polarization-angle-division diversity wireless transmitter according to claim 12,

wherein the first receiving antenna receives a linearly polarized wave, and

wherein the second receiving antenna is set up at an angle between 85 and 95 degrees with the first receiving antenna and receives a linearly polarized wave.

16. The polarization-angle-division diversity wireless receiver according to claim 12,

wherein the multi-delay composing means performs polarization phase rotation on the first received signal and the second received signal at each predetermined delay time and adds up the received signals;

wherein the multi-delay composing means performs path difference phase correction on each of the received signals added up on the basis of path differences, and

wherein the multi-delay composing means composes the received signals thus corrected.

17. The polarization-angle-division diversity wireless receiver according to claim 16,

wherein the polarization phase rotation and the path difference phase correction are determined so as to maximize the intensity of the composed received signals.

18. The polarization-angle-division diversity wireless receiver according to claim 16,

wherein the polarization phase rotation and the path difference phase correction are determined so as to minimize the error rate of the composed received signals following the demodulation thereof.

20. A polarization-angle-division diversity communication system comprising:

either of

a first polarization-angle-division diversity wireless transmitter comprising;

a first modulating unit modulating an information signal having a first frequency by a second frequency to output a first modulated signal; and

an electromagnetic wave transmitting unit transmitting the first modulated signal using two independent polarized waves and multiplies the polarized waves by a third frequency,

wherein the electromagnetic wave transmission means includes;

a second modulating unit modulating the first modulated signal by the third frequency to obtain a first output signal;

a first transmitting antenna which transmits the first output signal using a first polarized wave;

a phase shifting unit shifting a phase of the third frequency by a predetermined angle;

a third modulating unit modulating the first modulated signal by the shifted third frequency to obtain a second output signal; and

a second transmitting antenna which transmits the second output signal using a second polarized wave;

or

a second polarization-angle-division diversity wireless transmitter comprising;

a first modulating unit modulating an information signal of a first frequency by a second frequency to output a first modulated signal,

a fourth modulating unit modulating the information signal by a fourth frequency slightly different from the second frequency to output a fourth modulated signal,

a first composing unit composing the first modulated signal and the fourth modulated signal and further performing modulation by a third frequency caused by the difference between the second frequency and the fourth frequency to output a first output signal,

a second composing unit composing the first modulated signal and an inversion signal of the inverted fourth modulated signal and further performing modulation by the third frequency generated from the difference between the inverted second frequency and the inverted fourth frequency to output a second output signal,

a first transmitting antenna which transmits the first output signal using a first polarized wave, and

a second transmitting antenna which transmits the second output signal using a second polarized wave; and

a polarization-angle-division diversity wireless receiver according to claim 16,

wherein the polarization-angle-division diversity wireless transmitter performs a predetermined training operation for transmitting predetermined known information before information transmission or reception, and

wherein, in the training operation, the polarization-angle-division diversity wireless receiver determines the polarization phase rotation and the path difference phase correction so as to minimize the error rate of the composed received signals following the demodulation thereof.

19. A polarization-angle-division diversity communication system comprising:

either of

a first polarization-angle-division diversity wireless transmitter comprising;

a first modulating unit modulating an information signal having a first frequency by a second frequency to output a first modulated signal; and

an electromagnetic wave transmitting unit transmitting the first modulated signal using two independent polarized waves and multiplies the polarized waves by a third frequency,

wherein the electromagnetic wave transmission means includes;

a second modulating unit modulating the first modulated signal by the third frequency to obtain a first output signal;

a first transmitting antenna which transmits the first output signal using a first polarized wave;

a phase shifting unit shifting a phase of the third frequency by a predetermined angle;

a third modulating unit modulating the first modulated signal by the shifted third frequency to obtain a second output signal; and

a second transmitting antenna which transmits the second output signal using a second polarized wave;

or

a second polarization-angle-division diversity wireless transmitter comprising;

a first modulating unit modulating an information signal of a first frequency by a second frequency to output a first modulated signal,

a fourth modulating unit modulating the information signal by a fourth frequency slightly different from the second frequency to output a fourth modulated signal,

a first composing unit composing the first modulated signal and the fourth modulated signal and further performing modulation by a third frequency caused by the difference between the second frequency and the fourth frequency to output a first output signal,

a second composing unit composing the first modulated signal and an inversion signal of the inverted fourth modulated signal and further performing modulation by the third frequency generated by the difference between the inverted second frequency and the inverted fourth frequency to output a second output signal,

a first transmitting antenna which transmits the first output signal using a first polarized wave, and

a second transmitting antenna which transmits the second output signal using a second polarized wave;

wherein the polarization-angle-division diversity wireless transmitter performs a predetermined training operation for transmitting predetermined known information before information transmission or reception, and

wherein, in the training operation, the polarization-angle-division diversity wireless receiver determines the polarization phase rotation and the path difference phase correction in such a manner as to maximize the intensity of the composed received signals.