JP2795090B2 - Apparatus and method for compensating interference signal generated in non-regenerative wireless relay station - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art FIG. 8 is a block diagram showing an example of the configuration of a conventional regenerative digital radio relay system, taking two adjacent channels as an example.

[0003] The modulated signals generated by the modulators 101 and 102 at the transmitting radio station are frequency-converted by the transmitters 103 and 104 into a predetermined radio frequency band and multiplexed by the demultiplexer 105 in the radio frequency band. Transmitting antenna 106
And transmitted to the next wireless station. The regenerating radio station receives the modulated signal sent from the transmitting radio station by using the receiving antenna 129, demultiplexes the signals into each channel by the demultiplexing device 130, and converts the frequency to the intermediate frequency band by using the receiving devices 131 and 132. I do. The modulated signals that have been frequency-converted to the intermediate frequency band are amplified to predetermined levels by the automatic gain control circuits 133 and 134, and are reproduced as signals transmitted by the respective demodulators 135 and 136. The reproduced signal is used by a waveform equalizer 13 to compensate for waveform distortion generated in the propagation path.
7, 138.

[0004]

In such a conventional configuration, a modulation / demodulation device is required for each relay station, which complicates the configuration of the relay device, and has problems in power consumption and economy. The present invention adopts a non-regenerative relay system that eliminates the modem in the relay station to solve the above problems,
Furthermore, collectively compensating for interference noise added at each non-regenerative relay station in a regenerative radio station having a modem, a waveform equalizer, and an interference compensator to provide communication equivalent to the transmission quality of the regenerative relay system. With the goal.

[0005] In the present invention, additive interference noises to be collectively compensated are adjacent channel passing interference and cross polarization interference.

[0006] Adjacent channel passing interference means that when a signal is demultiplexed and multiplexed at a non-regenerative relay station, the demultiplexing and multiplexing filter has a wide band. Unnecessary for a signal) is input to an adjacent signal transmission system, and this is interference caused by multiplexing with the original desired signal in the form of a desired signal again at the time of multiplexing.

[0007] Cross polarization interference refers to the case where a signal is transmitted using polarization planes (V polarization, H polarization) that are orthogonal to each other in the same frequency band, from V polarization to H polarization or V polarization. This is interference caused by leaking from the wave into the H polarization.

[0008]

SUMMARY OF THE INVENTION The present invention relates to a transmitting radio station having a modulator, and a reproducing radio station having a demodulator, a waveform equalizer, and a cross polarization interference compensator corresponding to the modulator. Having at least one non-regenerative relay station between the transmitting radio station and the regenerative radio station, a non-regenerative relay device provided in the non-regenerative relay station converts a received signal into an intermediate frequency for each system. And a transmission frequency converter for converting to a required transmission frequency, and a transmission amplifier for amplifying to a required transmission level. A reproducing apparatus having a reference frequency oscillator and a phase locked oscillator for inputting an output signal of the reference frequency oscillator and generating a required transmission / reception local signal for each system of a plurality of channels; Means for supplying the output signal of the periodic oscillator to the transmission / reception frequency converter to achieve local synchronization between the systems, and adding the interference noise generated in the non-regenerative relay station in the regenerative radio station to the waveform equalizer and Means for collectively compensating by a cross polarization interference compensator.

[0009] As means for achieving 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, as means for achieving local synchronization,
Means are provided for supplying an output signal of the phase locked oscillator and a signal generated by frequency conversion of the output signal of the phase locked oscillator with another reference frequency oscillator to a transmission / reception frequency converter.

If two or more reference frequency oscillators are provided, and one of the reference frequency oscillators fails, the other is switched to another reference frequency oscillator, and its output signal is input to the phase locked oscillator, A means for supplying an output signal of the synchronous oscillator to the transmission / reception frequency converter is provided.

[0012]

According to the above arrangement, the frequency conversion of the modulated signal is performed using the transmission / reception local signal whose phase is synchronized with each other. Further, since the cross-polarization interference is added to the modulation signal with coherency, it is possible to collectively compensate for the cross-polarization interference in the reproducing wireless station having the waveform equalizer and the cross-polarization interference compensator.

[0013]

FIG. 1 is a block diagram showing the configuration of a first embodiment of the present invention, which is an example in which additive noise due to adjacent channel passing interference is compensated.

The relay system shown in the figure shows an example composed of a transmitting radio station, a non-regenerative relay station, and a regenerative radio station. Hereinafter, a case where the non-regenerative relay station is one station (two hops) will be described. .

In the figure, a transmitting radio station modulates a modulator 10.
Signals modulated by 1, 102 are transmitted by transmitting apparatus 103,
After frequency conversion to a radio frequency band via 104, the signal is multiplexed by the demultiplexer 105 and transmitted to the non-regenerative relay station 139 using the transmission antenna 106.

A signal received by the non-regenerative relay station 139 using the receiving antenna 107 is split into a predetermined channel by the splitter 108, and then the signal is received by the receiver 10 for each channel.
9 and 110. The modulated signals received by the receivers 109 and 110 are output from phase-locked oscillators (PLO) 113 and 116 which receive the output signal of the reference frequency oscillator 111 and generate required reception local signals, and mixers 112 and 114. Through an intermediate frequency band.

FIG. 9 shows an example of the configuration of a phase locked oscillator (PLO) 906 necessary for synchronizing transmission and reception local signals. In the figure, a signal from a reference frequency oscillator 901 is input to a phase comparator 902 and generates an output voltage corresponding to a phase difference from an output signal of the frequency divider 905. This output voltage is filtered by a low-pass filter called a loop filter 903 to remove unnecessary components included in the output of the phase comparator.
The filter output controls a voltage controlled oscillator (VCO) 904 to generate a transmit / receive local signal required to frequency-convert the modulated signal to a predetermined frequency band. VCO90
One of the four outputs is divided by a frequency divider 905 into a reference frequency oscillator 9.
The frequency is divided to the output frequency of 01 and input to the phase comparator 902. The VCO 904 outputs a radio frequency according to the control signal voltage, and the reference frequency oscillator 901 outputs the radio frequency.
Output a frequency lower than the oscillation frequency of

Thus, the reference frequency oscillator is integrated into one,
By splitting the output signal into a plurality of signals and inputting them to the respective PLOs, it is possible to generate transmission / reception local signals which are phase-synchronized with each other.

The output of the reference frequency oscillator 111 input to the PLOs 113 and 116 is amplified to a required level using an amplifier 115 to compensate for a level drop due to branching. The fluctuation of the reception level due to the propagation path is controlled by the automatic gain control circuit 11.
7, 118, and at a predetermined level the transmitting device 11
9 and 120. In the transmission devices 119 and 120,
The output signal of the reference frequency oscillator 111 is branched, and the output signal is input to the PLOs 123 and 126. Transmission device 1
The modulated signals input to 19 and 120 are PLO 123 and 1
The frequency-converted signal is again converted into a radio frequency band via the mixer 121 and 124 and the phase-synchronized transmission local signal having 26 outputs. Each frequency-modulated signal is supplied to an amplifier 12
After being amplified to a predetermined transmission level using the transmission antenna 2, the signal is multiplexed by the demultiplexer 127, and transmitted to the reproducing radio station having a demodulator and a waveform equalizer using the transmission antenna 128. At this time, since the transmission / reception local signals in the transmission / reception device of the non-regenerative relay station 139 are phase-synchronized with each other, adjacent channel passing interference can be treated as waveform distortion.
The modulated signal received by the regenerating radio station using the receiving antenna 129 is demultiplexed into each channel by the demultiplexing device 130, and the output signal is input to the receiving devices 131 and 132. The modulated signals that have been frequency-converted by the receiving devices 131 and 132 into a predetermined intermediate frequency band are output to the automatic gain control circuits 133 and 133.
The signal is input to each of the demodulation devices 135 and 136 via 134.
Adjacent channel passing interference included in the modulated signals frequency-converted into baseband signals by the demodulators 135 and 136 is compensated by the waveform equalizers 137 and 138.

FIG. 2 is a block diagram showing the configuration of the second embodiment of the present invention.

The difference between this embodiment and the first embodiment shown in FIG. 1 is that the output of the reference oscillator 111 is branched into two, one of which is provided to the PLO 113 in the receiving device 109 and the other is provided to the transmitting device 119.
This is a point that the local signal is generated by inputting the signal to the PLO 123 in the inside. The transmission / reception local signal generated in this manner is branched, and the modulated signal is frequency-converted to a predetermined frequency band via mixers 112, 114, 121 and 124. At this time, the local signal input to the mixer 114 in the reception device 110 and the mixer 124 in the transmission device 120
Is amplified to a predetermined level using an amplifier 115 in order to compensate for a level drop due to branching.

FIG. 3 is a block diagram showing the configuration of the third embodiment of the present invention.

The difference between this embodiment and the first embodiment shown in FIG. 1 is that, when generating transmission and reception local signals which are phase-synchronized with each other, the output of the reference frequency oscillator 111 is branched in the receivers 109 and 110 and input to the PLOs 113 and 116. After that, a local signal is generated, and the transmission devices 119 and 120 generate a different frequency oscillator 30 different from the reference frequency oscillator 111.
1 to convert the received local signal into mixers 302 and 304.
Is to convert the frequency through the filter and pass through the filters 303 and 305 to generate a transmission local signal. At this time, in order to compensate for a decrease in level due to a plurality of branches of the output of the reference frequency oscillator 111, the oscillator output is amplified to a predetermined level using the amplifier 115 and then input to the PLO 116.

FIG. 4 is a block diagram showing the configuration of the fourth embodiment of the present invention.

This embodiment differs from the first embodiment of FIG. 1 in that reference frequency oscillators 111 and 111A are connected
9 and 110 are provided, respectively, and these are switched using a switch 401 to achieve a duplex oscillator.

Thus, for example, the reference frequency oscillator 111
In the event of a failure, switch 401 switches to another reference frequency oscillator 111A. The output signal of switch 401 is branched, and PLO 113, 116, 123 and 1
Input to 26. At this time, the input to PLOs 116, 123 and 126 is a reference frequency oscillator (111 or 1).
11A) To compensate for the level drop due to the branch of the output signal,
The signal is amplified to a predetermined level using the amplifier 115. The modulated signal is frequency-converted to a predetermined frequency band through mixers 112, 114, 121 and 124 using the transmission / reception local signal generated in this manner.

FIG. 5 is a block diagram showing the configuration of the fifth embodiment of the present invention.

This embodiment is different from the fourth embodiment shown in FIG. 4 in that the receivers 109 and 110 respectively include reference frequency oscillators 111 and 111A and switches 401 and 401A, and one of the receivers (109 or 110) itself. In the event of a failure, the other receiver (110,
109) has a reference signal oscillator (111 or 11).
1A), the oscillators 111 and 111A and the switch 4 are switched by the switches 401 and 401A.
The point is that the duplexing of 01A and 401A is achieved. Here, the switches 401 and 401A have a function of selecting only one of the frequency oscillator outputs in conjunction with each other, and the output signals thereof are combined by the hybrid 501, and the PLOs 113 and 1A are combined.
16, 123 and 126. This hybrid 501 has sufficient isolation characteristics when one of two inputs is disconnected. Also, P
The input signals to LOs 116, 123 and 126 are amplified to a predetermined level using amplifier 115 in order to compensate for a decrease in level due to branching of hybrid 501 output signal.

FIG. 6 is a block diagram showing the configuration of the sixth embodiment of the present invention, which is an example in which additive noise due to adjacent channel interference and additive noise due to cross polarization interference are compensated.

In the figure, a modulating device 60 is used in a transmitting radio station.
The signals modulated by 1, 602, and 603 are frequency-converted into radio frequency bands via transmitting devices 604, 605, and 606, and then polarized and multiplexed by a demultiplexing device 607, and transmitted to a non-regenerative relay station using a transmitting antenna 608. 658. In the demultiplexer 607, the output signals of the modulators 601 and 602 are combined as H polarization, and the output signal of the modulator 603 is combined as V polarization. Here, the output signals of the modulators 602 and 603 are combined in the same frequency band on mutually orthogonal polarization planes.
Since the cross-polarization interference compensator has a baseband configuration, the V / H polarization modulation signal and the transmission local signal of the transmitting wireless station are synchronized between the V / H polarizations.

At the non-regenerative relay station 658, the receiving antenna 609
Are received by the demultiplexer 610, the signals are demultiplexed into the channels of the respective polarizations, and then the reception devices 611 and 611 for the respective channels are used.
Input to 612 and 613. Receivers 611, 61
2 and 613, the output signals of PLO 616, 619 and 621, which take the output signal of reference frequency oscillator 614 as an input signal and generate required local signals, and the intermediate frequency band through mixers 615, 617 and 620. Is frequency-converted. At this time, PLO61
9, 621, the output signal of the reference frequency oscillator 614 is supplied to the amplifiers 618, 6
22 to a required level. Fluctuations in the reception level due to the propagation path are absorbed by the automatic gain control circuits 623, 624 and 625, and at a predetermined level the transmission device 62
6,627 and 628. Transmission device 626,
At 627 and 628, the reference frequency oscillator 614
The output signal is branched, and the output signal is
4 and 637. Modulated signals input to transmitting apparatuses 626, 627 and 628 are
The frequency-converted transmission local signals, which are the outputs 4 and 637, are converted again into the radio frequency band via mixers 629, 632 and 637. Each frequency-converted modulated signal is amplified to a predetermined transmission power using amplifiers 630, 633, and 636 and then multiplexed on a predetermined polarization plane by a demultiplexer 638, and then demodulated using a transmission antenna 639. The signal is transmitted to a regenerative radio station having a waveform equalizer and a cross polarization interference compensator. At this time, the non-regenerative relay station 6
58 transceivers (611, 612, 613, 626,
Since the transmission and reception local signals in 627 and 628) are phase-synchronized with each other, adjacent channel passing interference can be treated as waveform distortion, and cross polarization interference is added to the modulated signal while maintaining coherency. At the regenerative radio station, the modulated signal received using the receiving antenna 640 is demultiplexed by the demultiplexing device 641 into each polarization channel, and the output signal is input to the receiving devices 642, 643 and 644.
The modulated signals that have been frequency-converted by the receiving devices 642, 643, and 644 to a predetermined intermediate frequency band are passed through automatic gain control circuits 645, 646, and 647, and are then demodulated by the demodulating devices 64.
8, 649 and 650. Adjacent channel passing interference included in the modulated signal frequency-converted into the baseband signal by the demodulator is compensated by the waveform equalizers 651, 652 and 653. The cross polarization interference included in the modulated signal is reduced by the cross polarization interference compensators 654, 655.
, A reference signal is extracted from the modulated signal on the different polarization side, and is compensated through adders 656 and 657.

This embodiment is an example in which a cross-polarization interference compensation technique is added to the first embodiment shown in FIG. 1. A method for synchronizing a transmission / reception local signal using a reference frequency oscillator output signal is described in the first embodiment. The same operation is performed even if the second embodiment, the third embodiment, the fourth embodiment, and the fifth embodiment are changed.

FIG. 7 is a block diagram showing a configuration of a seventh embodiment of the present invention, and showing a configuration of a multi-relay non-regenerative relay system.

The non-regenerative relay system is basically a system aiming at an economic effect, and the effect appears during multiple relays.

The relay system shown in FIG.
It is composed of non-regenerative relay stations 702 and 703 and a regenerative radio station 704. At this time, the modulated signal modulated by the transmitting wireless station is transmitted to the next non-regenerative relay station 702 using the transmitting antenna 705. The non-regenerative relay station 702 receives the modulated signal using the reception antenna 706, amplifies it to a required transmission level, and sends it to the next non-regenerative relay station 703 using the transmission antenna 707. The non-regenerative relay station 703 receives the modulated signal using the reception antenna 708, processes the received modulated signal in the same procedure as the non-regenerative relay station 702, and sends it to the next non-regenerative relay station using the transmission antenna 709. . The non-regeneratively relayed modulated signal is received by the wireless station 704 having a demodulator and a waveform equalizer via the receiving antenna 710 and demodulated. The interference noise added by the non-regenerative relay station is collectively compensated by the waveform equalizer and the cross-polarization interference compensator of the regenerative radio station.

[0036]

FIG. 10 shows the effect of the present invention.

FIG. 6 shows the transmission characteristics of the first embodiment of FIG. 1, and shows the signal power to noise power ratio (C) obtained in a 3-hop configuration (2 non-regenerative relay stations) when 16QAM is used for the modulation signal.
9 is a calculation result of NR) versus bit error rate (BER) characteristics.

As shown in the figure, by synchronizing the transmission / reception local signal in the non-regenerative relay station according to the present invention, waveform equalization having additive noise of adjacent channel passing interference added to the desired modulation signal in the regeneration radio station is performed. When the compensation is performed by the waveform equalizer, an improvement effect of about 5 dB can be obtained as compared with the case where the waveform equalizer is not used. In addition, as compared with the current regenerative relay system, characteristic degradation due to non-regenerative relay can be suppressed to within 0.5 dB.

As described above, the non-regenerative relay system has an effect that it can maintain almost the same transmission quality as the regenerative relay system, and can realize a significant cost reduction by not having a modem.

[Brief description of the drawings]

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

FIG. 5 is a block diagram showing a fifth embodiment of the method for compensating for an interference signal generated in a non-regenerative wireless relay station according to the present invention.

FIG. 6 is a block diagram showing a sixth embodiment of a method for compensating for an interference signal generated in a non-regenerative wireless relay station according to the present invention.

FIG. 7 is a block diagram showing a seventh embodiment of the method for compensating for an interference signal generated in a non-regenerative wireless relay station according to the present invention.

FIG. 8 is a block diagram showing a configuration example of a reconstructed digital wireless relay system which is a conventional system.

FIG. 9 is a block diagram showing a phase locked oscillator (PLO).

FIG. 10 is an error rate characteristic diagram showing the effect of the present invention.

[Explanation of symbols]

101, 102 Modulator 103, 104, 119, 120 Transmitter 105, 108, 127, 130 Demultiplexer 106, 128 Transmit antenna 107, 129 Receive antenna 109, 110, 131, 132 Receiver 111, 111A Reference frequency oscillator 112 , 114, 121, 124 mixers 113, 116, 123, 126 phase-locked oscillators (P
LO) 115 Amplifier 117, 118, 133, 134 Automatic gain control circuit 122, 125 Transmission amplifier 135, 136 Demodulator 137, 138 Waveform equalizer 139 Non-regenerative relay station 301 Reference frequency oscillator 302, 304 Mixer 303, 305 Band pass Filter 401, 401A Switch 501 Hybrid 601, 602, 603 Modulator 604, 605, 606, 626, 627, 628 Transmitter 607, 610, 638, 641 Demultiplexer 608, 639 Transmit antenna 609, 640 Receive antenna 611, 612 , 613, 642, 643, 644 Receiver 614 Reference frequency oscillator 615, 617, 620, 629, 632, 635 Mixer 616, 619, 621, 631, 634, 637 Phase locked oscillator (PLO) 18, 622, 630, 633, 636 Amplifier 623, 624, 625, 645, 646, 647 Automatic gain control circuit 648, 649, 650 Demodulator 651, 652, 653 Waveform equalizer 654, 655 Cross polarization interference compensator 656,657 Adder 658 Non-regenerative relay station 701 Transmitting radio station 702,703 Non-regenerative relay station 704 Regenerating radio station 705,707,709 Transmit antenna 706,708,710 Receiving antenna 901 Reference frequency oscillator 902 Phase comparator 903 Loop filter 904 voltage controlled oscillator (VCO) 905 frequency divider 906 phase locked oscillator (PLO)

Claims (5)

(57) [Claims] A transmitting radio station including a plurality of systems of modulation devices; a reproduction radio station including a demodulation device, a waveform equalizer, and a cross polarization interference compensator corresponding to the modulation devices; and the transmission radio station. And at least one non-regenerative relay station between the non-regenerative relay station and the regenerative radio station. The non-regenerative relay device provided in the non-regenerative relay station has a receiving frequency for converting a received signal into an intermediate frequency band for each system. A hybrid relay system comprising a converter, an automatic gain amplifier for correcting a level variation due to a propagation path, a transmission frequency converter for converting to a required transmission frequency, and a transmission amplifier for amplifying to a required transmission level. The regenerative repeater has a reference frequency oscillator, and a phase-locked oscillator that inputs an output signal of the reference frequency oscillator and generates a required transmission local signal and reception local signal of each system. Means for supplying an output signal of the phase locked oscillator to the transmission frequency converter and the reception frequency converter to achieve local synchronization between the systems; and a phase of interference noise generated at the non-regenerative relay station in the regenerative radio station. Means for collectively compensating for the addition by the waveform equalizer and the cross-polarization interference compensator. A device for compensating an interference signal generated in a non-regenerative wireless relay station, comprising: 2. The system according to claim 1, further comprising means for supplying an output signal of the phase locked oscillator to the transmission frequency converter and the reception frequency converter of another system. 2. The compensating device according to 1. 3. A means for achieving the local synchronization, wherein the output signal of the phase-locked oscillator and a signal generated by frequency-converting the output signal of the phase-locked oscillator with another reference frequency oscillator are respectively transmitted to the transmission frequency converter. 2. The compensating device according to claim 1, further comprising means for supplying a signal to said receiving frequency converter. 4. The system according to claim 1, wherein said reference frequency oscillator is provided in each system, and when one of said reference frequency oscillators fails, said reference frequency oscillator is switched to another reference frequency oscillator and is input to said phase locked oscillator. 2. The compensating device according to claim 1, further comprising means for supplying the following to the transmission frequency converter and the reception frequency converter. 5. A transmission radio station having a plurality of systems of modulation devices, a reproduction radio station having a demodulation device, a waveform equalizer, and a cross polarization interference compensator corresponding to the modulation devices, and the transmission radio station. And at least one non-regenerative relay station between the non-regenerative relay station and the regenerative radio station. The non-regenerative relay device provided in the non-regenerative relay station has a receiving frequency for converting a received signal into an intermediate frequency band for each system. A reference frequency oscillator in a hybrid relay system including a converter, an automatic gain amplifier for correcting a level variation due to a propagation path, a transmission frequency converter for converting to a required transmission frequency, and a transmission amplifier for amplifying to a required transmission level. And inputting the output signal of the reference frequency oscillator to each of the non-regenerative repeaters having a phase-locked oscillator for generating a required transmission local signal and a reception local signal for each system. Then, following the step of supplying the output signal of the phase-locked oscillator to the transmission frequency converter and the reception frequency converter to achieve local synchronization between the respective systems, the signal is generated at the non-regenerative relay station in the regenerative radio station. A method of compensating for an interference signal generated in a non-regenerative wireless relay station, comprising a step of collectively compensating for addition of interference noise by the waveform equalizer and the cross-polarization interference compensator.