JPS596089B2 - Control method for radio wave emission - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a radio wave emission control method for controlling radio wave emission from each radio station to eliminate interference when communicating between multiple radio stations using radio waves of the same frequency. It is something.

When performing such control, one of the multiple radio stations that make up one radio communication system becomes the control station, the other radio stations become controlled stations, and the radio wave emission from all the controlled stations is controlled. The availability status is controlled by a signal from the control station.

FIG. 1 is a block connection diagram showing an example of a control station used in the conventional method, in which 1 is a selection signal generation circuit, 2 is an idle signal generation circuit, and 3 is a transmitter.

FIG. 2 is a block connection diagram showing an example of a controlled station used in the conventional method, in which 5 is a receiver, 6 is a selection signal reception filter, 7 is an idle signal reception filter, 8 is a control circuit,
9 is a relay coil, 10 is a transmitter, 11 is a relay contact operated by the relay coil 9, and 12 is a press talk switch. FIG. 3 is an operation time chart showing the operation in the conventional method, in which FIG. 3a shows the transmission signal from the transmitter 3, FIG. Figure c shows the currents in the relay coils 9 in unselected controlled stations. The horizontal axis in FIG. 3 represents time. The format of the selection signal and the blank line signal is determined by the design of this wireless communication system, but in the examples shown in Figures 1, 2, and 3, these signals are Assume that it is a tone signal of a frequency, for example, a blank line signal has a frequency f.

The selection signal for selecting the first controlled station has a frequency f
It is assumed that the signals are detected by filters 6 and 7, respectively. Next, the operation will be explained.

When a control station wants to make a call to a specific controlled station (temporarily assumed to be the first controlled station), at the start of the call, a selection signal as shown in FIG. Send via. In each controlled station, a selection signal received by a receiver 5 is detected by a filter 6 and sent to a control circuit 8. When a controlled station other than the first controlled station detects a signal of frequency fl from the filter 6, it knows that it has not been selected by the controlled station for a call, and the control circuit 8 sends the relay coil 9 to the controlled station. , and the relay contact 11 is opened. This state is called a blocked state, and in a controlled station that is in a blocked state, the transmitter 10 cannot enter the transmitting state even if the press talk switch 12 is pressed to perform a transmitting operation. In the first controlled station, since it is predetermined that the selection signal for the own station is a tone of frequency f1, the filter 6
If a signal with frequency f1 is detected from , no current flows to relay coil 9, and by operating press talk switch 12, transmitter 10 can be put into the transmitting state, and only the selected controlled station becomes the control station. You can make calls and there will be no interference from other controlled stations. If the call between the control station and the first controlled station ends under the above conditions, the control station will send the third
Frequency F shown in figure a.

Transmit a blank line signal. At each controlled station, the idle signal received by the receiver 5 is detected by the filter 7 and sent to the control circuit 8.
If the controlled station is in a blocked state and current is flowing through the relay coil 9, this current is cut off to release the blocked state. By the way, the conventional method was designed mainly for wireless communication systems consisting only of fixed wireless stations, and the radio wave propagation between the control station and each controlled station is stable, and the transmission from the control station is It was assumed that the various signals transmitted would be stably received by all controlled stations. However, if the wireless communication system includes wireless stations that move, such as in-vehicle wireless stations and mobile wireless stations, the relative position between the control station and the controlled station becomes unstable, making radio wave propagation unstable. In that case, it becomes difficult to receive various signals stably, resulting in a drawback that problems occur. For example, if a controlled station in a blocked state misses the idle signal, the controlled station will remain in a blocked state forever and will be unable to transmit. This invention was made in order to eliminate the drawbacks of the conventional method as described above, and the controlled station that receives the blockage signal from the control station enters a blockage state from that point on and continues this blockage state for a predetermined period of time. By providing a function to automatically release the blockage state after that, even in wireless stations with unstable radio wave propagation such as in-vehicle radio stations and mobile radio stations, the blockage state can be reliably released and stable communication control can be achieved. The purpose is to provide a method.

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 4 is a block connection diagram showing a control station used in an embodiment of the present invention, and FIG. 5 is a block connection diagram showing a controlled station used in an embodiment of the invention. The same reference numerals as in FIGS. 1 and 2 indicate the same or corresponding parts, 13 is a block signal generation circuit, 14 is a block signal reception filter, and 15 is a time limit circuit. Further, FIG. 6 is an operation time chart showing the operation in the method of the present invention, in which FIG. 6a is a transmission signal from the transmitter 3 of FIG. 4, and FIG. , and FIG. 6c shows the current in the relay coil 9 at an unselected controlled station, respectively. The horizontal axis in FIG. 6 is time t. In this case, it is assumed that the blocking signal has a frequency Fc, the selection signal for the first controlled station has a frequency f1, and the selection signal for the second controlled station has a frequency F2. Next, the operation of this invention will be explained.

From the control station, a blockage signal is transmitted from the blockage signal generating circuit 13 via the transmitter 3 as shown in Fc in FIG. 6a. At each controlled station, this is received by the receiver 5 and passed through the filter 14.
The control circuit 8 activates the time limit circuit 15 based on the judgment of the control circuit 8, and the time limit circuit 15 causes a current to flow through the relay coil 9 for a predetermined time TR as shown in FIG. keep. On the other hand, the control station transmits a selection signal (signal of frequency f1 in the example shown in FIG. The signal is then transmitted via the transmitter 3. Each controlled station receives this selection signal by the receiver 5 and detects it by the filter 6. However, if the selection signal is not addressed to the own station, the control circuit 8 does not perform any operation, and the blockage detected earlier by the filter 14 is detected by the control circuit 8. The signal maintains the closed state. However, only the first controlled station knows that it has been selected from the frequency f1 of the selection signal detected by the filter 6, controls the control circuit 8, and controls the time limit circuit 15.
If it has been activated, it is restored, and if it is not activated, its activation is prohibited and no current is applied to the relay coil 9 as shown in FIG. 6b. Therefore, only the selected first controlled station is placed in a state where it can communicate with the control station. However, as shown in FIG. 6c, even in controlled stations other than the first controlled station, after a predetermined period of time TR has elapsed after the controlled station is in the blocked state due to the blocking signal from the control station, the blocked state is dynamically changed. It will be released and you will be able to make calls.

Next, as shown in FIG. 6a, Ts
After a certain period of time, a blockage signal is sent again to put each controlled station into a blocked state, and then a selection signal is sent to the selected controlled station (6th
In the example shown in the figure, only the second controlled station) is released from the blocked state. If Ts>TR, as is clear from FIG. 6, an interrupt call from a controlled station that is not selected becomes possible. T
Needless to say, if R≧Ts, the above-mentioned interrupting call becomes impossible, and according to the method of the present invention, the time range in which interrupting calls are possible can be adjusted by changing Ts. In the embodiment shown in FIG. 6a, the first controlled station is selected first and the second controlled station is selected after time Ts, but the signal of frequency f1 is repeatedly transmitted as the selection signal, and other The first call is placed between the time slots that allow interrupt calls from controlled stations.
If it is possible to continue the call with the selected controlled station, or if Ts is a long enough time to complete the call with one selected controlled station, TR can be set correspondingly and other controlled stations can be continued. It is also possible to prevent interference from the control station.

As described above, according to the method of the present invention, in each controlled station, the blockage state is automatically released by the operation of the time limit circuit 15, so that a signal such as an empty line signal or the like to release the blockage state is sent. This eliminates the need for communication control even in unstable communication circuits such as in-vehicle radio stations and portable radio stations, and allows adjustment of the time slot in which interrupt calls can be accepted.

[Brief explanation of drawings]

Figure 1 is a block connection diagram showing an example of a control station used in the conventional method, Figure 2 is a block connection diagram showing an example of a controlled station used in the conventional method, and Figure 3 is the operation in the conventional method. 4 is a block connection diagram showing a control station used in an embodiment of the present invention. FIG. 5 is a block connection diagram showing a controlled station used in an embodiment of the present invention. FIG. 6 is an operation time chart showing the operation in the method of this invention. In these figures, 1 is a selection signal generation circuit, 3 and 10 are transmitters, 5 is a receiver, 6 is a selection signal reception filter, 8 is a control circuit, 9 is a relay coil, 11 is a relay contact, and 13 is a blockage signal. A generating circuit, 14 a blockage signal reception filter, and 15 a timer circuit.

Claims (1)

[Claims] 1. In a wireless communication system consisting of a control station that controls communications and a plurality of controlled stations whose communications are controlled by this control station, it is impossible for the control station mentioned above to emit radio waves to all of the plurality of controlled stations mentioned above. a step of transmitting a blockage signal to control the controlled station; a step of automatically controlling the controlled station to enter a blockage state in which it is impossible to emit radio waves after detecting the blockage signal at the controlled station; At the stage where the continued controlled stations are automatically released from the blocked state and are able to emit radio waves, the control station controls one selected controlled station to release its blocked state and enable it to emit radio waves. a step of transmitting a selection signal to select the controlled station, and a step of automatically controlling the controlled station to release the blocked state of the own station when the selection signal is detected by the controlled station and the selection signal selects the own station. A method of controlling radio wave emission characterized by: