JPH0685780A - Radio transmitter - Google Patents

Abstract

PURPOSE:To improve the reliability of the system by transmitting reset information mutually between cross polarized wave interference eliminating equipments by the both-polarized-wave transmission system so as to relieve the trouble at the maintenance. CONSTITUTION:Reset switch circuits 313, 413 stop the compensation of cross polarized wave interference eliminating devices 105, 205 under the control of an external device and sets the reset state. The state of the reset switch circuit 313 or 413 is transmitted to the other reset switch circuit 413 or 313, and cross polarized wave interference eliminating devices 105, 205 of both polarized planes are simultaneously reset by resetting the one reset switch circuit 313 or 413. Thus, when either of the cross polarized wave interference eliminating devices is reset, the trouble of operation at maintenance is avoided and the reliability is improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for digital signal wireless transmission by a dual polarization transmission system. The present invention relates to a wireless transmission device capable of improving workability during maintenance of a cross polarization interference canceller.

[0002]

2. Description of the Related Art In a digital radio transmission system, a dual polarization transmission system, which increases the transmission capacity per band by transmitting modulated signals by using different polarization planes at the same frequency, is practically used as a means for effective frequency use. Has been converted. In this dual polarization transmission system, the interference between both polarizations is an important factor that determines the line quality, and a cross polarization interference canceller is introduced to detect and cancel this interference, as shown in FIG. .

This cross polarization interference canceller must be provided with a reset means for stopping the canceling operation under external control in order to confirm the operation at the time of testing, and specifically, the coefficient of the weighting circuit. There is known a method in which the reset state is achieved by setting 0 to zero.

Such a cross polarization interference canceller is used for controlling a modulation signal of different polarization or a baseband signal after demodulation and generating a compensation signal. Since the operation may affect the operation of the device on the other polarization plane, it is necessary to reset not only the cross polarization interference canceller for the own polarization but also the cross polarization interference canceller for the polarization plane during maintenance. It was

[0005]

In such a conventional dual polarization transmission system, since the cross polarization interference canceling devices for the respective polarization planes are reset independently, it is necessary to set the reset state individually. However, there is a drawback that operations such as maintenance are complicated.

The present invention eliminates such drawbacks, and by resetting either one of the cross polarization interference canceling devices, it is possible to reset at the same time, thereby reducing the complexity during maintenance. The purpose is to provide.

[0007]

According to the present invention, a transmitting station and a receiving station are connected by a radio communication path via respective antennas, and the receiving station uses polarized waves orthogonal to each other from the transmitting station. Wireless receivers that individually receive the received digital signals, and two cross-polarization interference cancellers that detect and cancel the interference between the polarizations of the received digital signals. One of the interference cancellers has a reset switch circuit that stops the operation of canceling the inter-polarization interference by an external control signal and sets the reset state, and the other cross polarization interference that orthogonalizes the information indicating the state of the reset switch circuit. And a transmission circuit for transmitting to the removing device.

It is preferable that the reset switch circuit includes means for transmitting a signal for automatically setting the other cross polarization interference canceling device to the reset state when the reset state is set.

[0009]

When a digital signal using polarized waves orthogonal to each other at the same frequency is being transmitted, one of the cross polarization interference cancellers provided corresponding to each orthogonal polarization plane is reset from the outside. When the control signal for sending the control signal is sent, the reset switch circuit operates, first, the device is set to the reset state, and then the reset switch circuit of the other cross polarization interference canceler is reset to the reset state via the transfer circuit. Communicate information to set. The transmitted reset information can control the other reset switch circuit.

As a result, when either one of the cross polarization interference cancelers is reset, the complexity of the operation during maintenance is eliminated and the reliability can be improved.

[0011]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of the embodiment of the present invention.

In the embodiment of the present invention, the bandwidth B1 is set on the transmitting station side.
64QA which outputs 64QAM modulated signal (IF signal) of
The center frequency f of the M modulator 101 and the 64QAM modulated signal is
A transmitter 102 for converting to a radio frequency of ₀ and outputting;
16QAM that outputs a 16QAM modulated signal (IF signal) having a bandwidth B2 different from the bandwidth B1 of the 4QAM modulated signal
The modulator 201 and the 16QAM modulated signal have a center frequency f _0.
The transmitter 202 for converting to the radio frequency and outputting the same, and the transmitting antenna 11.

The output from the transmitter 102 is the transmission antenna 1
1 is connected to the horizontal polarization side and the output of the transmitter 202 is connected to the vertical polarization side of the transmission antenna 11, so that the 64QAM modulated signal uses the horizontal polarization and
The QAM modulated signals are transmitted by using vertically polarized waves.

The receiving station side is connected to a receiving antenna 12 and a horizontal polarization side of the receiving antenna 12, and a receiver for frequency-converting a radio frequency 64QAM modulated signal received in the horizontal polarization into an IF band signal. 103 and the receiving antenna 12
Connected to the vertical polarization side of the receiver, which receives the radio frequency 16QAM modulated signal received in the vertical polarization as a signal in the IF band, and the outputs of the receivers 103 and 203 as input, Cross-polarization interference canceling devices 105 and 205 for removing the interference component from the different polarization generated in 1. and 64QAM demodulator 10 for demodulating the outputs of the cross-polarization interference canceling devices 105 and 205, respectively, and outputting a baseband signal
4 and 16 QAM demodulator 204.

The cross polarization interference canceling devices 105 and 205 each have a delay amount of 1 / th when the output of the receiver 203 is input.
A delay circuit with taps composed of delay lines 301, 302, 303, 304 equal to B2, and delay lines 401, 40 equal to 1 / B1 to which the output of the receiver 103 is input
It has a delay circuit with taps composed of 2, 403 and 404. Each tap output has a 64QAM demodulator 104 and 16
Tap weighting circuits 305, 306, 307, 308, 309, 40 controlled by weighting control signal generating circuits 312, 412 that identify and determine the output baseband signal of the QAM demodulator 204 and generate weighting control signals.
5, 406, 407, 408, and 409, respectively, and then combined by combining circuits 310 and 410 to be output as cross polarization interference cancellation signals. These cross polarization interference cancellation signals are respectively coupled to the coupling circuit 31.
64QAM is a signal that is combined with the signals from the receivers 103 and 203 at 1 and 411 and the cross polarization interference component is removed.
It is output to the demodulators 104 and 16QAM demodulators 204.

Here, the feature of the present invention is that the reset switch circuits 313 and 413 are provided, so that the reset switch circuits 313 and 314 are externally controlled so that the cross polarization interference canceling devices 105 and 205 are provided.
Stop the compensation operation of and set the reset state. The state of the reset switch circuit 313 or 413 is transmitted to the other reset switch circuit 413 or 313, and by resetting the one reset switch circuit 313 or 413, the cross polarization interference canceling apparatus 1 for both polarization planes 1
It is possible to reset 05 and 205 at the same time.

[0017]

As described above, according to the present invention, either one of the cross polarization interference canceling devices is transmitted by mutually transmitting the reset information between the cross polarization interference canceling devices of both polarization transmission systems. By resetting, it is possible to simultaneously reset the cross polarization interference cancellers of different polarization planes, which can reduce the complexity of maintenance and improve the system reliability. .

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIG. 2 is a block diagram showing a configuration of a conventional example.

[Explanation of symbols]

 11 transmitting antenna 12 receiving antenna 101 64QAM modulator 102, 202 transmitter 103, 203 receiver 104 64QAM demodulator 105, 205 cross polarization interference canceller 201 16QAM modulator 204 16QAM demodulator 301-304, 401-404 delay line 305-309, 405-409 Tap weighting circuit 310, 311, 410, 411 Coupling circuit 312, 412 Weighting control signal generating circuit 313, 413 Reset switch circuit

Claims (2)

[Claims] 1. A transmitting station and a receiving station are connected by a wireless communication path via respective antennas, and the receiving station individually receives digital signals using mutually orthogonal polarized waves from the transmitting station. In a wireless transmission device comprising two receivers and two cross-polarization interference cancellers for detecting and canceling interference between polarizations of a received digital signal, one of the cross-polarization interference cancellers: A reset switch circuit that stops the operation of removing the cross-polarization interference and sets the reset state by a control signal from, and a transmission circuit that transmits the information indicating the state of the reset switch circuit to the other cross polarization interference canceling device orthogonal to each other. A wireless transmission device comprising: 2. The radio according to claim 1, wherein the reset switch circuit includes means for transmitting a signal for automatically setting the other cross polarization interference canceller to the reset state when the reset state is set. Transmission equipment.