JPH04179323A - Radio communication system - Google Patents

Abstract

PURPOSE:To reduce the deterioration of line quality and the probability of generation of the hit of a line by detecting the 'leaking quantity' signal of an interference signal into a main signal, estimating the quantity of the interference signal, and controlling the transmission signal level of the main signal. CONSTITUTION:An interference wave removal equalizer 6 which synthesizes in reverse phase the reception output of a first receiver 5 and the leaking quantity signal being the reception output of a second receiver 10 owing to the output signal of a second transmitter 9, which is included in the reception output of the first receiver 5, and which outputs a signal obtained by removing the interference signal from the reception output of the first receiver 5 is provided. A detection means 12 detects the leaking quantity signal and transmits is to a transmission side where a first transmitter 2 is installed. The output signal level of the first transmitter 2 is controlled by the transmitted leaking quantity signal. Thus, necessary equalizing quantity for the interference signal exceeds the equalizing capacity of the interference wave removal equalizer 6, and possibility for the deterioration of line quality and the occurrence of line hit can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a wireless communication system, and particularly to a wireless communication system in which different information is simultaneously transmitted using carrier waves of the same frequency and different polarizations.

[Conventional technology]

A conventional wireless communication system of this type will be explained with reference to a block diagram shown in FIG.

Information on the first channel is input to a modulator (MOD) 1, and the output signal, in which a carrier wave of a predetermined frequency is modulated, is amplified by a transmitter (TX) 2. will be sent out. The signal is then propagated by radio waves (also referred to as a wireless transmission path) and received by the antenna 4 on the receiving side. A receiver (RX) 5 amplifies the received signal, and the received signal, that is, the received signal of the first channel, is input to an interference wave canceller (XPrC) 6. - On the other hand, the information of the second channel is input to a modulator (MOD) 8,
The output signal modulated by the carrier wave having the same frequency as that of the first channel is transmitted to the antenna 3 on the transmitting side via the transmitter (TX>9).
The output signal of the first channel is transmitted with a different polarization, for example, a horizontal polarization. Then, it is received by the receiving antenna 4, amplified by the receiver (RX) 10, and demodulated by the demodulator (DEM).
) 11 outputs information on the second channel.

Here, due to interference in the wireless transmission path between the antenna 3 on the transmitting side and the antenna 4 on the receiving side, and the transmission path consisting of the antennas 3 and 4, the output signal of the transmitter 9 is also transmitted to the receiver 5 as an interference signal. is input.

Therefore, a part of the output signal of the receiver 10 is input to the interference wave removal equalizer 6. The interference wave removal equalizer 6 sets the input signal to a level equal to the level of the interference signal at the reception output end of the receiver 5, and separates the received signal of the first channel which is the main signal and the second signal which is the same as the interference signal. Synthesizes the channel received signals in opposite phase. The received signal from which the interference signal caused by the output signal of the transmitter 8 has been removed is output to a demodulator (DEM>7), and the demodulator 7 demodulates it into first channel information.

Note that an interference wave removal equalizer may be installed between the receiver 10 and the demodulator 11 of the second channel to equalize the interference signals, similarly to the first channel.

[Problem to be solved by the invention]

The conventional wireless communication system described above relies only on the equalization ability of the interference wave removal equalizer to reduce the probability of occurrence of line quality deterioration and momentary line interruption due to fluctuations in the propagation state of the wireless transmission path. However, when considering various transmission conditions such as fluctuations in reception levels due to fading and multiwave interference in the wireless transmission path, and deterioration over time of different polarization discrimination of antennas, the required amount of equalization for interference signals becomes There is a possibility that the equalization ability of the interference wave removal equalizer will be exceeded, resulting in deterioration of line quality and instantaneous line interruption.

[Issues and means to solve them]

The wireless communication system of the present invention includes first and second transmitters that use carrier waves of the same frequency, first and second receivers corresponding to the transmitters, and first and second transmitters that use carrier waves of the same frequency. a transmitting antenna commonly connected to the first receiver and a receiving antenna commonly connected to the first and second receivers;
A wireless communication system that performs cross-polarized radio propagation between the transmitting antenna and the receiving antenna, the receiving output of the first receiver and the second receiving output included in the receiving output of the first receiver. The leakage amount signal, which is the received output of the second receiver, and the level corresponding to the level of the interference signal caused by the output signal of the transmitter are combined in reverse phase, and the received output of the first receiver is combined with the In a wireless communication system having an interference wave removal equalizer that outputs a signal from which an interference signal has been removed, the detection means detects the leakage amount signal, and the detected leakage amount signal is sent to the first transmitter. and a control means for controlling the output signal level of the first transmitter based on the transmitted leakage amount signal.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

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

Here, modulator 1 and modulator 8. Transmitters 2 and 9, transmitter antenna 3. Receiving side antenna 4° receiver 5 and same 10. Interference wave removal equalizer6. The connection relationships, operations, etc. of the demodulators 7 and 11 have been described in the conventional embodiment shown in FIG. 1, so redundant explanations will be omitted.

In a detector (DET) 12, an interference wave removal equalizer 6 inverts the first channel received signal outputted from the receiver 5 and the second channel received signal outputted from the receiver 10. The signal level of the second channel (hereinafter referred to as
(abbreviated as "leakage amount" signal) is detected. The transmission line 14, which is a wireless or wired transmission line, is detected by the detector 12 [leakage amount J signal is transmitted to the control circuit (CONT) 13 provided on the transmission side where the transmitter 2 etc. is installed. to be transmitted. The control circuit 13 controls the amplification degree of the transmitter 2 based on the "leakage amount" signal, and controls the level of the output signal.

As an example, the level of the interference signal with respect to the first channel signal, that is, the output level of the receiver 10 of the second channel, increases relatively, and the required amount of interference signal with respect to the first channel signal input to the interference wave canceller 6 increases. When the incorporation amount j increases to the extent that it exceeds the equalization ability of the interference wave removal equalizer 6,
Control as follows. That is, when the level of the output signal of the transmitter 2 is increased so that the output signal level of the first channel increases relative to the output signal level of the second channel, which is an interference signal, the interference wave removal equalizer 6 The amount of interference signal due to the second channel can be suppressed within the equalization capability range of .

〔Effect of the invention〕

As explained above, the present invention detects the "leakage amount" signal of the interference signal to the main signal for interference signal removal, estimates the interference signal amount based on the signal, and controls the output signal level of the main signal. By doing so, it is possible to suppress the amount of interference signals within the equalization range of the interference wave removal equalizer against interference signal level fluctuations due to the propagation state of the wireless transmission path, etc., and prevent line quality deterioration and line interruptions. It has the effect of reducing the probability of occurrence.

[Brief explanation of drawings]

FIG. 1 is a block diagram of an embodiment of the wireless communication system of the present invention, and FIG. 2 is a block diagram of a conventional embodiment. 1.8...Modulator, 2.9...Transmitter, 3.4...
・Antenna, 5.10... Receiver, 6... Interference wave removal equalizer, 7.11... Demodulator, 12... Detector,
13... Control circuit, 14... Transmission line.

Claims (1)

[Claims] 1. First and second transmitters using carrier waves of the same frequency, first and second receivers corresponding to the transmitters, and the first and second transmitters A wireless communication system comprising a transmitting antenna commonly connected to the first receiver and a receiving antenna commonly connected to the first and second receivers, and performing different polarization radio propagation between the transmitting antenna and the receiving antenna. and the level of the interference signal attributable to the output signal of the second transmitter included in the reception output of the first receiver and the reception output of the first receiver. Wireless communication comprising an interference wave removal equalizer that performs anti-phase synthesis with a leakage amount signal that is the reception output of the second receiver and outputs a signal from which the interference signal has been removed from the reception output of the first receiver. In the method, a detection means for detecting the leakage amount signal; and a detection means for detecting the leakage amount signal;
and a control means for controlling the output signal level of the first transmitter based on the transmitted leakage amount signal. Wireless communication method. 2. The wireless communication system according to claim 1, wherein when the leakage amount signal exceeds a predetermined value, the control means starts controlling the output signal level of the first transmitter.