JPH0669903A - Compensation method for cross polarized wave interference caused in non-regenerative radio relay station - Google Patents

Abstract

PURPOSE:To provide the interference compensation method in which a non-regenerative relay station is adopted for a radio relay station and cross polarized wave interference noise added by a non-regenerative relay station is compensated at a regenerative radio station altogether. CONSTITUTION:A radio transmission station multiplexes a system having a vertically polarized wave and a horizontally polarized wave and transmits the multiplexed signal. A radio relay station 145 being a non-regenerative relay station converts a reception signal of a radio frequency into a signal at an intermediate frequency band by using a reception local signal, amplifies the signal with the adjusted gain and converts the signal again into a radio frequency band signal by using a transmission local signal and transmits the converted signal. A repeater of the system having each polarized signal is provided with phase synchronization oscillators 112, 115, 123, 127 driven by reference frequency oscillators 113, 124 and applying the transmission and reception local signals to each section, and the transmission local signal and the reception local signal in the repeater are locally synchronized respectively. The regenerative relay station uses waveform equalizers 139, 140 and cross polarized wave interference compensation devices 141, 142 to compensate the interference noise generated in the non-regenerative relay station 145 altogether.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to means for collectively compensating additive noise of cross polarization interference generated in a non-regenerative radio relay station in a radio station having a demodulator and a cross polarization interference compensator.

[0002]

2. Description of the Related Art FIG. 5 shows an example of the configuration of a conventional regenerative digital radio relay system, which shows polarization planes (V / H polarization) orthogonal to each other.
FIG. 3 is a block diagram showing an example of two channels having a. The modulated signals generated by the modulators 101 and 102 at the transmitting radio station are
The frequency is converted into a predetermined radio frequency band by the transmission devices 103 and 104, and the signals are multiplexed in the radio frequency band by the demultiplexing device 105 and then transmitted to the next radio station using the transmission antenna 106. In the regenerative radio station, the modulated signal sent from the transmission radio station is received using the receiving antenna 131, demultiplexed into each channel by the demultiplexing device 132, and frequency conversion to the intermediate frequency band is performed using the receiving devices 133 and 134. To do. The modulated signal frequency-converted to the intermediate frequency band is amplified to a predetermined level by automatic gain control circuits 135 and 136, and demodulators 137 and
The signal transmitted by 138 is reproduced. The regenerated signal passes through the waveform equalizers 139 and 140 to compensate the cross polarization interference generated in the propagation path, and then the cross polarization interference compensator.
A reference signal is extracted from the polarization-side signal using 141 and 142, and is compensated via adders 143 and 144.

[0003]

In such a conventional configuration, since each relay station requires a modulation / demodulation device, the configuration of the relay device becomes complicated, and there are problems in power consumption and economical efficiency. The present invention adopts a non-regenerative relay system that eliminates a modulator / demodulator in a relay station in order to solve the above problems,
Further, it is an object of the present invention to collectively compensate the interference noise added at each non-regenerative relay station by a regenerative radio station having a modulator / demodulator and an interference compensator, and to provide communication equivalent to the transmission quality of the regenerative relay system. In the present invention, the additive interference noise collectively compensated is cross polarization interference. Cross-polarization interference refers to the case where V polarization is changed to H polarization when signals are transmitted using polarization planes (V polarization, H polarization) orthogonal to each other in the same frequency band.
This is interference caused by leaking from V polarization to H polarization.

[0004]

DISCLOSURE OF THE INVENTION The present invention provides a transmitting radio station having a modulator, a regenerating radio station having a demodulator and a cross polarization interference compensator corresponding to the modulator, and the transmitting radio station. N stations (N = 1,2, ...)
In the non-regenerative repeater device provided in the non-regenerative repeater station, the non-regenerative repeater device has a receiving frequency converter for converting a received signal to an intermediate frequency for each system and an automatic gain for correcting level fluctuation due to a propagation path. In a hybrid relay system including an amplifier, a transmission frequency converter for converting to a required transmission frequency, and a transmission amplifier for amplifying to a required transmission level, a reference frequency oscillator and an output signal of the reference frequency oscillator are input to the non-regenerative device. However, it has a phase-locked oscillator that generates the required transmit / receive local signals for each system with V and H polarizations that are orthogonal to each other, and supplies the output signal of the phase-locked oscillator to the transmit / receive frequency converter to achieve local synchronization between each system. And the additive noise of cross polarization interference generated in the non-regeneration relay station in the regenerative radio station is collectively corrected by the cross polarization interference compensator. And means for compensating. As means for achieving the local synchronization, there is provided means for supplying an output signal of the phase locked oscillator to a transmission / reception frequency converter of another system. Further, the above reference frequency oscillator is provided in two or more systems, and when one reference frequency oscillator fails, the other reference frequency oscillator is switched to and the output signal thereof is input to the phase locked oscillator, Is provided to the transmission / reception frequency converter.

[0005]

According to the above structure, the modulated signals are frequency-converted by using the transmission / reception local signals whose phases are synchronized with each other, so that the cross polarization interference generated in the non-regenerative repeater station is added to the modulated signals with coherency. Therefore, it becomes possible to collectively compensate in the regenerative radio station having the cross polarization interference compensator.

[0006]

1 is a block diagram showing the configuration of a first embodiment of the present invention. The relay system shown in the figure shows an example of a transmission wireless station, a non-regenerative relay station, and a regenerative wireless station. Hereinafter, the case where there is one non-regenerative relay station (two hops) will be described. In the figure, the transmitting radio station is a modulator 101
, 102, the signals modulated by the transmitters 103, 104
After being frequency-converted into a radio frequency band via the, the demultiplexing device 105 polarization-multiplexes and transmits to the non-regenerative relay station 145 using the transmitting antenna 106. In the demultiplexing device 105, the output signal of the modulator 101 is an H polarization, and the output signal of the modulator 102 is a V polarization, and they are combined in the same frequency band with polarization planes orthogonal to each other. Since the cross polarization interference compensator wave and the baseband configuration are used, the modulation signals of both polarizations of the transmission wireless station and the transmission local signal are synchronized between the polarizations. The signal received using the receiving antenna 107 in the non-regenerative repeater station 145 is demultiplexed by the demultiplexing device 108 into each polarization channel, and then input to the receiving devices 109 and 110 for each channel. The modulated signals received by the receiving devices 109 and 110 are input to the output signal of the reference frequency oscillator 113 and output through the phase locked oscillators (PLO) 112 and 115 that generate the required received local signals and the mixers 111 and 114. The frequency is converted to the intermediate frequency band. FIG. 6 shows an example of the structure of the phase-locked oscillator (PLO) 606 required for synchronizing the transmitted and received local signals. In the figure, the signal from the reference frequency oscillator 601 is
It is input to the phase comparator 602 and generates an output voltage corresponding to the phase difference from the output signal of the frequency divider 605. This output voltage is filtered by a low-pass filter called loop filter 603 to remove unnecessary components contained in the output of the phase comparator, and the filter output controls the voltage controlled oscillator (VCO) 604 to output the modulated signal to a predetermined frequency band. Generate the transmit / receive local signal required for frequency conversion to. One of the VCO604 outputs is a frequency divider
The frequency is divided by 605 up to the output frequency of the reference frequency oscillator 601 and input to the phase comparator 602. This VCO 604 outputs a radio frequency by the control signal voltage, and the reference frequency oscillator 60
1 outputs a low frequency compared to the oscillation frequency of VCO604.
In this way, by using one reference frequency oscillator, branching its output signal into a plurality of signals, and inputting them to each PLO, it is possible to generate transmit / receive local signals that are phase-synchronized with each other. The reference frequency oscillator 113 input to the PLO 112, 115 is an amplifier for compensating for the level drop due to the branch.
It is amplified to the required level with 116. The fluctuation of the reception level due to the propagation path is absorbed by the automatic gain control circuits 117 and 118, and is input to the transmission devices 119 and 120 at a predetermined level. In the transmitters 119 and 120, the reference frequency oscillator 11
A reference signal oscillator 124 different from 1 is used, and its output signal is branched and input to PLO 123, 127. Transmitter 119,120
The modulated signal input to (1) is again frequency-converted into the radio frequency band via the phase-locked transmission local signals output from the PLOs 123 and 127 and the mixers 121 and 125. Where PLO12
The output of the reference frequency oscillator 124 input to 3,127 is amplified to a required level by using the amplifier 128 to compensate for the level drop due to the branch. Each frequency-converted modulated signal is
A regenerative radio station including a post-demultiplexing device 129, which has been amplified to a predetermined transmission level using amplifiers 122 and 126, and has a predetermined polarization plane, and a demodulation device and a cross polarization interference compensator using a transmission antenna 130. Sent to. At this time, since the transmission local signal and the reception local signal in the transmitter / receivers (109, 110, 119 and 120) of the non-regenerative repeater station 145 are mutually phase-locked, the cross polarization interference is modulated while maintaining coherency. Added to the signal. The modulated signal received using the receiving antenna 131 at the regenerative radio station is the demultiplexer.
The signals are demultiplexed into channels of each polarization by 132, and the output signals are input to receiving devices 133 and 134. Receivers 133, 134
The modulated signal frequency-converted to a predetermined intermediate frequency band by
Through the automatic gain control circuits 135 and 136, the demodulators 137 and
Type in 138. Cross-polarization interference included in the modulated signals frequency-converted into baseband signals by the demodulators 137 and 138 is transmitted through the waveform equalizers 139 and 140, and then cross-polarization interference compensators 141 and 142 are used. A reference signal is extracted from the modulated signal of and is compensated through adders 143 and 144. FIG. 2 is a block diagram showing the configuration of the second embodiment of the present invention. This embodiment is different from the first embodiment in FIG. 1 in that the transceivers 109 and 119 in the non-regenerative repeater station 145 have reference oscillators 113 and 124, respectively, and the reference frequency oscillator 113 and
The point is that the 124 output signals are input to the PLO 112 and 123, respectively, and the transmission / reception local signals are generated. The transmission / reception local signal generated in this way is branched to be mixed by the mixers 111 and 114.
, 121 and 125 to convert the frequency of the modulated signal into a predetermined frequency band. At this time, the mixer in the receiver 110
The reception local signal input to 114 and the transmission local signal input to the mixer 125 in the transmission device 120 are amplified to a predetermined level by using amplifiers 116 and 128 in order to compensate for the level reduction due to branching. FIG. 3 is a block diagram showing the configuration of the third exemplary embodiment of the present invention. This embodiment is different from the first embodiment in FIG. 1 in that the reference frequency oscillators 113 and 113A are used as receivers.
These are provided in 109 and 110, respectively, and by switching them using switch 301, the duplication of the oscillator is achieved. As a result, for example, if the reference frequency oscillator 113 fails, the switch 301 switches to another reference frequency oscillator 113A.
Switch to. Switch 301 output signal is branched to PLO1
Enter 12, 115, 123 and 127. At this time PLO11
The inputs to 2, 115, 123 and 127 are amplified to a predetermined level using amplifiers 116, 128 and 128A to compensate for the level drop due to the branching of the reference frequency oscillator (113 or 113A) output signal. Using the transmitted / received local signals generated in this way, the mixers 111, 114, 121 and
The modulated signal is frequency-converted via 125 to a predetermined frequency band. FIG. 4 is a block diagram showing the configuration of the fourth embodiment of the present invention and showing the configuration of the multi-relay non-regenerative relay system. The non-regenerative relay system is basically aimed at the economic effect, and the effect appears when there are multiple relays. The relay system shown in the figure is composed of a transmission wireless station 401, non-regenerative relay stations 402 and 403, and a regenerative wireless station 404. At this time, the modulated signal modulated by the transmitting wireless station is sent to the non-regenerating relay station 402 which is the next wireless station using the transmitting antenna 405. The non-regenerative relay station 402 receives the modulated signal using the receiving antenna 406, amplifies it to a required transmission level, and then sends it to the non-regenerative relay station 403, which is the next wireless station, using the transmitting antenna 407. The non-regenerative relay station 403 receives the modulated signal using the receiving antenna 408, processes the received modulated signal in the same procedure as the non-regenerative relay station 402, and sends it to the next non-regenerative relay station using the transmitting antenna 409. . The modulated signal thus non-regenerated and relayed is received by the radio station 404 having a demodulator and a waveform equalizer via the receiving antenna 410 and demodulated. The additive noise of cross polarization interference generated in the non-regenerative relay station is collectively compensated by the cross polarization interference compensator included in the regenerative radio station.

[0007]

As described above, according to the present invention, one or a plurality of reference frequency oscillator outputs are branched into a plurality of outputs, and the outputs are input to a phase-locked oscillator provided in a transmitter / receiver to transmit / receive local signals in phase with each other. By generating the signal, it is possible to perform frequency conversion of the modulation signals that are phase-synchronized with each other, and it is possible to add additive noise of cross polarization interference generated in the non-regenerative relay station to the modulation signal while maintaining coherency. As a result, additive noise due to cross polarization interference can be collectively compensated for in a regenerative radio station having a demodulator and a cross polarization interference compensator. From the above, it can be said that the non-regenerative relay system to which the compensation method of the present invention is applied can maintain almost the same transmission quality as the regenerative digital wireless relay system, and can realize a significant cost reduction by not having a modulator / demodulator. effective.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a method of compensating for cross polarization interference generated in a non-regenerative wireless relay station according to the present invention.

FIG. 2 is a block diagram showing a second embodiment of a method for compensating for cross polarization interference occurring in a non-regenerative wireless relay station according to the present invention.

FIG. 3 is a block diagram showing a third embodiment of a method of compensating for cross polarization interference occurring in a non-regenerative wireless relay station according to the present invention.

FIG. 4 is a block diagram showing a fourth embodiment of a method of compensating for cross polarization interference generated in a non-regenerative wireless relay station according to the present invention.

FIG. 5 is a block diagram showing a configuration example of a reproduction digital wireless relay system which is a conventional system.

FIG. 6 is a block diagram showing a phase-locked oscillator (PLO).

[Explanation of symbols]

 101, 102 Modulator 103, 104, 119, 120 Transmitter 105, 108, 129, 132 Demultiplexer 106, 130 Transmit antenna 107, 131 Receive antenna 109, 110, 133, 134 Receive 111, 114, 121, 125 Mixer 112, 115, 123, 127 Phase-locked oscillator (PLO) 113, 113A Reference frequency oscillator 116, 128, 128A, amplifier 122, 126 Transmit amplifier 117, 118, 135, 136 Automatic gain control circuit 137, 138 Demodulator 139, 140 Waveform equalizer 141, 142 Cross polarization interference compensator 143, 144 Adder 145 Non-regenerative relay station 301 Switch 401 Transmission wireless station 402, 403 Non-regenerative relay station 404 Regenerative wireless station 405, 407, 409 Transmission antenna 406, 408,410 Receive antenna 601 Reference frequency oscillator 602 Phase comparator 603 Loop filter 604 Voltage controlled oscillator (VCO) 605 Divider 606 Phase locked oscillator (PLO)

Claims (3)

[Claims] 1. A transmitting radio station having a modulating device, a reproducing radio station having a demodulating device and a cross polarization interference compensator corresponding to the modulating device, and between the transmitting radio station and the reproducing radio station. At least one non-regenerative relay station,
The non-regenerative repeater device provided in the non-regenerative repeater station includes a reception frequency converter for converting a received signal into an intermediate frequency for each system, an automatic gain amplifier for correcting level fluctuation due to a propagation path, and a transmission frequency for converting to a required transmission frequency. In a hybrid relay system including a converter and a transmission amplifier that amplifies to a required transmission level, a reference frequency oscillator and an output signal of the reference frequency oscillator are input to the non-regenerative device, and V and H bi-polarizations orthogonal to each other are input. Means having a phase-locked oscillator for generating a required transmission / reception local signal of each system having a wave, and supplying an output signal of the phase-locked oscillator to a transmission / reception frequency converter to achieve local synchronization of a receiver and a transmitter between the systems In the regenerative radio station, the additive noise of cross polarization interference generated in the non-regeneration relay station is collectively collected by the cross polarization interference compensator. A method of compensating for cross-polarization interference generated in a non-regenerative wireless relay station, comprising: means for compensating. 2. The compensating method according to claim 1, further comprising means for supplying the output signal of the phase-locked oscillator to a transmission / reception frequency converter of another system as means for achieving the local synchronization. 3. A system comprising two or more reference frequency oscillators, and when one of the reference frequency oscillators fails, the other reference frequency oscillator is switched to and its output signal is input to the phase-locked oscillator. 2. The compensating method according to claim 1, further comprising means for supplying an output signal of the synchronous oscillator to the transmission / reception frequency converter.