JPH01200843A - System for resetting interference compensation between crossed polarizations - Google Patents

Abstract

PURPOSE:To smoothly operate a digital wireless line to use a crossed polarization by providing an input detecting circuit and automatically resetting a crossed polarization interference compensating circuit at a interfering wave when a zero code succeeds in the demodulating code of the interfering wave. CONSTITUTION:An input detecting circuit 3 selects digital codes m1I and m1Q of the identifying outputs of an identifier 21 of the other polarization at the interfering wave side and converts them to parallel data of p-column of an I channel and a Q channel to be shifted by a prescribed p-number of stages to exceed an n-number of scramble stages. Next, the data of the I channel and Q channel of the parallel of the p-column to be converted are gate-processed, the succession of codes 0 of the identifier 21 output in the n-number of scramble stages or above is detected, and by the detected output at a crossed polarization interference compensator 22, compensating signals m2I and m2Q are generated, and a resetting action is automatically executed. To both the I channel and Q channel of the output of a waveform distortion equalizer 12 of a main signal, the codes 0 of the compensating signals are added by adders 121 and 122. Thus, the wireless line of a crossed polarization use can be smoothly operated.

Description

[Detailed Description of the Invention] [Summary] In a digital radio relay station that performs multiplex transmission using horizontal and vertical cross-polarized signals at the same frequency that are scrambled, a transformer of the demodulation code of the main signal of one polarization is used. Regarding the cross-polarization interference compensation circuit that generates and adds to the output code of the versal equalizer a compensation signal that compensates for interference with the main signal from the demodulation code of the other polarization, and outputs the resulting signal, When the received signal of the wave is interrupted and its demodulation code becomes a series of "0" codes, the scramble code is descrambled and a compensation signal is generated to compensate for the interference from the demodulation code of the other polarization to the main signal. The purpose of this is to reset the cross-polarization interference compensator circuit so that it does not generate an erroneous compensation signal and add it to the main signal code. An input detection circuit is provided for detecting consecutive zero codes "0" of the demodulation code of the interference wave by gate processing the parallel codes of the p columns of the 1 channel and the Q channel shifted to the number of stages p exceeding The code "0" is generated from the output as a compensation signal and added to the output of the distortion equalizer for the main signal to stop compensation of cross-polarization interference with respect to the main signal of the interference wave signal.

[Industrial application field]

The present invention deals with waveform distortion of demodulated codes of main signals of polarized waves, etc. at a relay station of a digital radio line that relays radio signals multi-level modulated and scrambled using cross polarized waves that are orthogonal to each other at the same frequency. A compensation signal is generated and added to the output of the flower vase from the demodulation code of the interference wave of the other polarization, and the interference of the signal of the other polarization with the main signal is compensated for to create a correct waveform and transmitted to the next relay station. This invention relates to a cross-polarization interference compensation circuit.

[Conventional technology]

A conventional cross-polarization interference compensation circuit is shown in FIG.

The cross-polarization interference compensation circuit shown in FIG. 4 uses a discriminator 11A to level-identify the analog signals of the demodulated signals I and Q of the main signal of the radio signal that has been multi-value modulated and scrambled for the polarization at the relay station. and digital code n11. nl
Q, the waveform distortion is equalized in the time domain in the transversal equalizer 12A, and the equalized codes n2I, n2
(1 is output to the next relay station, but in a wireless line that uses cross-polarized waves of the same frequency, the main signal of the two polarized waves will always receive interference from the signal of the other polarized wave, although the level is low. demodulated signal IXIQX on the interference side of the polarized wave @ discriminator 21A
The level is identified by digital code m 11 + m I
The digital code converted to Q has a resistance of 1. In the cross polarization interference compensation circuit 22A using mlQ, compensation signals m2I, m
2Q, an adder 121A generates the output code n2L n2Q of the transversal equalizer 12A on the main signal side,
122A performs digital addition to compensate for interference.

Then, output signals Iout and Qout of the main signal with correct waveforms that have been compensated for interference from the other polarized wave are output to the next relay station.

[Problem that the invention seeks to solve]

As described above, the conventional cross-polarization interference compensation circuit generates the output codes n2I, n2Q of the transversal equalizer 12A with respect to the demodulation codes n1I, nlQ on the main signal side, and the demodulation codes mll, mlQ on the interference wave side. compensation signal m2
The correct waveform is obtained by digitally adding I and m2Q to compensate for interference waves leaking from other wave signals, but multilevel modulated digital signals generally avoid continuous transmission of code "0" and are transmitted In order to average the signal spectrum, a certain number of transmission codes are scrambled on the transmitting side to randomize the occurrence of transmission codes "1" and "Om" and to avoid continuous transmission of codes "0". , the receiving side performs reverse descrambling to restore the original code. Therefore, a compensation signal generated using a code obtained by descrambling the code of the other polarization multiplied by the cross-polarization interference compensator can prevent cross-polarization interference from the main signal code received and demodulated in the same way. Compensated. In other words, the compensation signal is a code “0” whose input code is a certain number or more.
” is not assumed to be continuous.

Therefore, the received signal on the interference wave side of the other polarization is cut off due to phasing or maintenance tests, and the demodulated signal lx,
When the level of Qx is zero for a long time, the code "0" continues in the output code of the discriminator 21A on the interference wave side, so the cross polarization interference compensator 22A detects the continuous code "0". ,
There is a problem in that an erroneous compensation signal is generated, and the adders 12I and 122 perform erroneous compensation, thereby worsening the waveforms of the output signals 1out and Qout of the main signal.

[Means for solving problems]

This problem occurs when the received signal on the interference wave side of the other polarization is cut off, the demodulated signals Ix and Qx become zero level, and the output code of the discriminator 21A on the interference wave side becomes a series of codes "0". The output code to the discriminator 21 is selected and the parallel data of the p columns of the I channel and Q channel shifted by a certain number of stages p exceeding the number of scrambling stages n is gate-processed, and the code of the output of the discriminator 21A on the interference wave side is determined. Detects continuous “0” and uses the detection output to generate a cross-polarization interference compensator 2 on the interference wave side.
In step 2, a so-called reset operation is performed to generate a code "0" as a compensation signal, and the adders 121 and 122 set the compensation signal as code "O" to both channel and Q channel.
This problem is solved by the configuration of the present invention in which the waveform distortion of the main signal is added to the output of the vase 12, that is, the output of the waveform distortion equalizer 12 of the main signal is output on the other side.

In the principle diagram of FIG. 1 showing the configuration of the cross-polarization interference compensator reset method of the present invention, 1 is a reception circuit for the main signal of the scrambled code of the polarization, and 2 is the reception circuit for the main signal of the scrambled code of the other polarization. This is a receiving circuit for an interference wave of a code scrambled by a certain number of stages n with a signal of .

11 is a demodulated signal 1.1 on the main signal side. A discriminator on the main signal side identifies the level of Q, converts it into digital codes n1I, nlQ, and outputs it; 12 is the output code n1I, nlQ of the discriminator 11 on the main signal side;
Distortion equalizers 121 and 122 add compensation signals m2I and m2Q from the interference wave side to the signal output n2I and Q signal output n2H of the output of the distortion equalizer 12 on the main signal side. 21 is an interference wave side discriminator that identifies the levels of the demodulated signals lx and Qx on the interference wave side of other polarization, converts them into digital codes m1I and mlQ, and outputs them; 22 is an interference wave side discriminator. Output codes m1I, mlQ of the device 21
Compensation signal l1 that compensates for cross-polarization interference from to the main signal side
The cross-polarization interference compensator 3 that generates and outputs 12 selects the output codes mll and mlQ of the discriminator 21 on the interference wave side, and selects the I channel and Q An input detection circuit that gate-processes parallel data of the channel to detect continuous "0" of the output codes mII and mlQ to detect continuous interruption of the input signal, the detection output of the input detection circuit 3: The cross polarization interference compensator 22 on the interference wave side generates a code "0" as a compensation signal, and the output codes n1I, n of the distortion equalizer 12 on the main signal side
The configuration is such that it is added to lH.

[Effect]

The main signal side discriminator 11 detects the I channel and Q channel analog signals 1. of the demodulated signals on the main signal side. The level of Q is identified, digital codes nll and nlQ are generated and output to a digital distortion equalizer 12. The distortion equalizer 12 equalizes the waveform distortion of the output codes n1I and nlQ of the main signal side discriminator 11 in the time domain, and outputs the equalized code outputs n2I,
n2Q is output to the adders 12I and 122, but since the digital radio signals to be transmitted use cross-polarized signals of the same frequency, the signal of the other polarization orthogonal to the polarization of the main signal may interfere with the main signal. The waveform of the output code of the main signal distortion equalizer 12 always has distortion.

The discriminator 21 on the interference wave side identifies the analog signal levels of the demodulated signals Ix and Qx of the interference wave of the other polarization, converts them into digital codes null and anti-Q, and outputs them to the cross-polarization interference compensator 22. do.

The cross-polarization interference compensator 22 generates compensation signals m2I and m2Q for compensating for interference to the main signal from the output codes m1I and a+IQ of the discriminator 21 on the interference wave side, and sends them to the adders 12I and 12.
Output to 2. The adder 12L122 adds the compensation signals m2I and m2Q from the cross-polarization interference compensation circuit 22 to the output codes n2I and n2Q of the main signal distortion equalizer 12, and outputs the output signals 1out and Qout as main signals with correct waveforms. Output.

The input detection circuit 3 selects the digital code m1I, n+IQ@M of the discrimination output of the other polarization discriminator 21 on the interference wave side, and selects the I channel and Ω channel shifted by a certain number of stages p exceeding the number of scrambling stages n. The data of the parallel I channel and Q channel of the converted p column is converted into parallel data of the p column, and gate processing is performed, and the discriminator 21 on the interference wave side
A continuation of the code "0" of the output of A for the number of scrambling stages n or more is detected, and based on the detected output, the code "0" is generated as compensation signals m2I and m2G in the cross-polarization interference compensator 22 on the interference wave side. A reset operation is performed, and the code "0" of the compensation signal is applied to both the Q channel of the output of the waveform distortion equalizer 12 of the main signal and the Q channel of the adder 12L 122.
Add at In other words, the reset method for cross-polarization interference compensation of the present invention is effective when the signal input on the interfering wave side is cut off for a long time due to fading or maintenance tests. The waveform distortion of the main signal will not worsen and the problem will be solved because the output of the other sins 12, such as waveform distortion of the main signal, will be output in its original form without adding the waveform erroneous compensation signal. It's true.

〔Example〕

FIG. 2 is a block diagram showing the configuration of a reset method for cross-polarization interference compensation according to an embodiment of the present invention.

In the block diagram in Figure 2, the main signal side is a horizontally polarized wave H, and the interference wave side is a vertically polarized wave ■ of the other polarized wave, and both are 2560A
This figure shows the circuit configuration after the demodulator of the receiving device of the relay station that transmits the multi-level signals of the 2560AH Q channel and the Q channel of the transmission signal, and the 2560AH 1 channel of the transmission signal and the low channel signal are scrambled at a certain number of stages. It is a signal that has been multiplied.

The discriminator 11 on the main signal side is composed of an A/D converter, and includes an analog demodulated signal 1. Identify and encode the level of Q, and write two digital codes n 11 + n for the Q channel and the Q channel.
Outputs IQ.

The distortion equalizer 12 for the digital codes nll and nlQ of the main signal is composed of a transversal equalizer, and the digital code n1 of the output of the discriminator 11 for the main signal of the horizontally polarized wave H.
I, nlQ are input, their waveform distortions are equalized in the time domain, and the equalized code outputs n2I, n2Q are sent to the adder 12.
Output to 1,122.

The vertically polarized wave V discriminator 21 on the interference side is also composed of an A/D converter, and identifies and encodes the levels of the 256 QAM modulated analog demodulated signals lx and Qx of the vertically polarized wave V, and distinguishes between the Q channel and Q two digital codes of the channel mll,
It generates mlQ and outputs it to the cross-polarization interference compensator 22.

The cross-polarization interference compensator 22 is composed of a compensation signal generator,
Scrambled output code ml of the discriminator 21 on the interference side
1 and mlQ, and generate compensation signals m2I and m2Q that compensate for the interference of the horizontally polarized wave H with the main signal, and output them to the adder 12L122.

The adders 121 and 122 have an I signal output n21 of the transversal equalizer output of the distortion equalizer 12 on the main signal side,
The compensation signals m2I and m2Q generated by the cross-polarization interference compensator 22 are added to the Q signal output n2H to generate the output signal Iout.
.

Output Qout.

The input detection circuit 3 includes a level selector 311.3 for each I channel and Q channel of the output of the discriminator 21 on the interference side.
IQ, a shift register 32L32Q with a constant number of stages p,
It is composed of AND gates 33L and 33Q and an OR gate 34, and the level selectors 311 and 31Q are, for example, 256
For QAM modulated signals, the center 2 of 16 levels
Select the level and input 11 and 1 as shown in Figure 3.
2.11 and I3. Three E to input 11 and 14 respectively
It is composed of X-OR gates 31L312, 313 and an AND gate 314 that performs AND processing on the output thereof.The output 01 of the AND gate 314 is sequentially shifted and inputted to shift registers 32I, 32Q with 9 stages larger than the number of scrambling stages, respectively. 9 columns of parallel data P1. PQ is input to AND gate 33I and AND gate 33Q and subjected to AND processing. Then, the output of the AND gate 331 and the output of the AND gate 33Q are input to the OR gate 34, and the parallel data P1. All codes of PQ are “1” consecutively.
”, it is determined that the input signals Ix and Qx of the vertically polarized wave V on the interfering side are continuously interrupted.

Then, the output "1" of the OR gate 34 is input to the cross-polarization interference compensator 22, and the compensation signal m2 output from the compensator 22 is
I, 1n2Q is disconnected and a code "0" is generated instead to perform a reset operation.

The reset method for cross-polarization interference compensation in this embodiment ensures that the signals lx and Qx on the interference wave side of the vertically polarized wave V are interrupted continuously for a long time, not by chance, but due to fading or maintenance tests. In this case, the cross-polarization interference compensation circuit 22 on the interference wave side is reset by the output of the input detection circuit 3, which has a simple configuration of registers and gates. The adder 12L122 compensates for the error and outputs the main signal 1out, Qout.
On the contrary, it does not get worse, so there is no problem.

〔Effect of the invention〕

As explained above, according to the present invention, the received signal of the interference wave of another polarization different from the polarization of the main signal is interrupted due to fading or maintenance tests, and the demodulation code of the interference wave has consecutive zero codes. In this case, the cross-polarization interference compensation circuit on the interfering wave side is automatically reset within the own station using a simple circuit.
The effect of smoothing the operation of a digital wireless line using cross-polarized waves can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a principle diagram showing the configuration of a reset method for cross-polarization interference compensation according to the present invention. FIG. 2 is a block diagram showing the configuration of a reset method for cross-polarization interference compensation according to an embodiment of the present invention. FIG. is a circuit diagram of a level selector according to an embodiment of the present invention, and FIG. 4 is a block diagram of a conventional cross-polarization interference compensation circuit. In the figure, 1 is a receiving circuit on the main signal side, 2 is a receiving circuit on the interference wave side, 11.21 is a discriminator, 12 is a distortion equalizer, 12I and 122 are adders, and 22 is a cross-polarization interference compensator. 3 is an input detection circuit, 311.31Q is a signal level selector, 321 and 320 are shift registers, 331.33G is an AND gate, 34
is an or gate.礪 礪－■ →＼ MEN ki ＼ Bound 14－ ← Obtain ≧ Ma

Claims (1)

[Claims] Demodulation codes of main signals (I, Q) of I channel and Q channel of one polarization among digital radio signals of two mutually orthogonal polarizations scrambled by a certain number of stages (n) Distortion equalizer (
A compensation signal (m2I, m2Q) that compensates for interference to the main signal from the demodulation code (m1I, m1Q) of the signal (Ix, Qx) of the other polarization is generated at the output (n2I, n2Q) of (12). ), add (121, 122) and output (Iou
t, Qout), the demodulation code (m1I
, m1Q) and select the level of the scramble stage number (n).
The demodulated code (m1
An input detection circuit (3) is provided to detect consecutive zero codes of I, m1Q), and the output of the input detection circuit (3) generates a compensation signal (m2I,
A code "0" is generated (22) as m2Q) and added to the output (n2I, n2Q) of the distortion equalizer (12) of the main signal to eliminate cross-polarization interference of the signal of the other polarization with the main signal. A reset method for cross-polarization interference compensation, which is characterized by stopping the compensation.