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

• US 20160226571A1
• Filed: 04/08/2016
• Published: 08/04/2016
• Est. Priority Date: 03/09/2011
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: TAKEI, Ken
• Granted Patent: US 9,722,687 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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. A polarization-angle-division diversity wireless transmitter comprising:

an electromagnetic wave transmitter to transmit two independent circularly polarized waves,

wherein the electromagnetic wave transmitter comprises;

a first modulator to modulate an information signal having a first frequency by a carrier having a second frequency to output a first modulated signal;

a second modulator to modulate the first modulated signal by a third frequency to obtain a first output signal;

a first transmitter which transmits the first output signal using a first polarization-angle-division diversity wireless transmitter;

a phase shifter to shift a phase of the third frequency to have a phase difference of 90 degrees;

a third modulator to modulate the first modulated signal by the phase-shifted third frequency to obtain a second output signal; and

a second transmitter which transmits the second output signal using a second polarization-angle-division diversity wireless transmitter, and

wherein the first and second transmitted output signals create the first and second circularly polarized waves rotating at the third frequency in opposite directions.

2. The polarization-angle-division diversity wireless transmitter according to claim 1,

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.

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

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

a phase shifter to shift a phase of the third frequency to have a phase difference of 90 degrees; and

an electromagnetic wave transmitter transmitting the first modulated signal using first and second independent polarized waves which are modulated by the third frequency and the phase-shifted third frequency, respectively,

the polarization-angle-division diversity wireless receiver comprising;

a plurality of antennas which receive the electromagnetic waves 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 corrector correcting the input signals for phase shifts caused by path differences so as to generate a plurality of received signals, respectively; and

a composer composing the plurality of received signals.

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

a polarization-angle-division diversity wireless transmitter comprising;

a first modulator to modulate an information signal having a first frequency by a second frequency to output a first modulated signal; and

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

wherein the electromagnetic wave transmitter includes;

a second modulator to modulate 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 shifter to shift a phase of the third frequency by a predetermined angle;

a third modulator to modulate 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 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, a 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.

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

a polarization-angle-division diversity wireless transmitter comprising;

a first modulator to modulate an information signal of a first frequency by a second frequency to output a first modulated signal,

a fourth modulator to modulate the information signal by a fourth frequency slightly different from the second frequency to output a fourth modulated signal,

a first composer 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 composer to compose the first modulated signal and an inversion signal of the inverted fourth modulated signal and further perform 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, a 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.