JPH0484524A - Relay system using tone squelch - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Summary] For example, among municipal disaster prevention administrative radio systems, the present invention is used in a mobile system that performs calls between a mobile station and a base station via a relay station. Regarding the relay system using tone squelch, ■Usage per system [-] In order to minimize the number of tone signals, it is necessary to install a tone signal generator and a base transmitter that can generate all the set tone signals. A base station that has a relay receiver and a relay transmitter that performs a relay operation only while detecting a tone signal addressed to its own station, and a mobile receiver that is in operation. In a wireless system comprising a mobile station that communicates with the base station via a relay station, a plurality of tone signals generated by the tone signal generator are superimposed on the base station, and one of the plurality of tone signals is superimposed on the base station.・Distortion improvement means is provided to suppress the frequency component expressed by linear combination using an integer of the frequency of the tone signal as a coefficient and apply it to the base transmitter, and multiple tone signals are simultaneously transmitted from the base station. The relay station is configured to allow a plurality of corresponding relay stations to perform relay operations simultaneously.

[Industrial application field]

The present invention provides, for example, a municipal disaster prevention administrative wireless system.
This article relates to a relay method using tone squelch used in mobile systems that conduct calls between mobile stations and base stations via relay stations.

The municipal disaster prevention administrative radio system provides local disaster prevention, emergency rescue,
This is a system that municipalities independently set up primarily for use in disaster recovery-related operations, and is also used during normal times for communication regarding general administrative affairs.

This system consists of a fixed system, a mobile system, a telemeter system, or a combination thereof.

The fixed system is 60M 11 from the master station installed in the municipality.
It is a system that transmits information to residents through Z-band wireless transmission channels, and the mobile system uses 400 MIIz-band radio waves to transmit information from base stations installed at the headquarters of each municipality through relay stations activated with tone signals. 2. For example, this is a system for communicating with a mobile station.

Here, the frequency of the above tone signal is up to 2, for example, 33
Therefore, in order to make effective use of tone signals, it is necessary to minimize the number of tone signals used per system.

[Conventional technology]

Figure 5 shows a conceptual diagram of the mobile system of the municipal disaster prevention administrative radio system.

As shown in the figure, the mobile system consists of base stations and relay stations.

It consists of a mobile station (for example, one for a vehicle-mounted station), and the radio waves of frequency F1 transmitted from the base station are transmitted to the No. 1 relay station and No. 1 relay station, which are activated by a tone signal described later.

2 relay station converts it into a radio wave of frequency F2 and sends it out again. As a result, information from the base station is transmitted to the mobile station angle and mobile station B.

Next, FIG. 6 is a block diagram of a conventional example, FIG. 6(a) is a block diagram of a base transmitter, and FIG. 6(b) is a block diagram of a relay transceiver.

The operation shown in FIG. 6 will be explained below with reference to FIG.

Here, the relay stations are No. 1 relay station and No. 2 relay station 2.
When the base station sends out a tone signal of frequency 1+, the No. I relay station performs a relay operation, and when it sends out a tone signal of frequency f2, the No. 32 relay station performs a relay operation, but when the base station sends out a tone signal of frequency f3, No, 1 when sending tone signal
It is assumed that the relay station and No. 2 relay station perform relay operations.

Further, the above tone signal is, for example, 501 (z~250
There are a maximum of 33 waves of signals with specified frequencies within Ilz.

First, the base station has a tone signal generator 1 shown in FIG. 6(a).
After adding the 1-tone signal of frequency f1 generated in step 5 and the audio signal to the modulator 111 to generate a modulated wave, the transmitter 112
The signal is sent to the No. 1 relay station at a predetermined transmission frequency and transmission power.

Here, the input level of the tone signal is set to be lower, for example, about 173, than the input level of the audio signal.

In No. 1 relay station, the receiving section 121 shown in FIG. 6(b)
After converting the frequency of the received signal, the received signal is amplified to a predetermined level and sent to the demodulator 122. The demodulator demodulates the input signal and extracts a demodulated signal consisting of an audio signal and a tone signal of frequency f1, which is passed through a bandpass filter 51 and a switch 5I.
Add to l13.

The band-pass filter 51 extracts a frequency f from the demodulated signal by 1.
Since the -on signal is extracted and applied to the detector 52, the detector applies the detection output to the switch SW via the OR gate 55. Therefore, since this switch is turned on (the state indicated by the dotted line), the audio signal is relayed to the mobile station via the modulation section 131 and the transmission section 132 on the transmission side at a predetermined transmission frequency and transmission power.

That is, since a voice signal and a tone signal of frequency f are simultaneously transmitted from the base station, the No. 1 relay station performs a relay operation while the voice signal is being transmitted from the base station to the mobile station.

Note that in order to relay to the No. 2 relay station, the base station may generate a tone signal of frequency f2 and send it to the relay station in the same manner as above.

Here, in order to send voice signals to the corresponding mobile stations via the No. 1 relay station and the No. 2 relay station, a 1.-tone signal of frequency f3 is sent. Because, No,
Relay station No. 1, No. 2, and Relay station No. 2 each have a bandpass filter 53 for extracting the signal of frequency f3 and a detector, so they perform a relay operation by driving switch SW3 in the same manner as described above.

[Problem to be solved by the invention]

In other words, only the relay station that has detected the tone signal can perform the relay operation (hereinafter referred to as tone squelch).
The possibility of base station radio waves propagating to unnecessary areas is reduced. For this reason, there is a strong possibility that implementation of tone squelch will become common in future trunk lines.

Here, if there are two relay stations, three waves of 1-tone signals are required, and if there are n stations, (n+1) waves of tone signals are required. On the other hand, the frequency of the tone signal is 3 as described above.
Since there is a limit of 3, there is a problem in that the number of tone signals used per system must be kept to a minimum in order to make effective use of tone signals.

The present invention aims to minimize the number of tone signals used per system.

[Means to solve problems]

FIG. 1 shows a block diagram of the principle of the first to third aspects of the present invention.

In the figure, 15 is a tone signal generator capable of generating all set tone signals, 11 is a base transmitter, and 12
is a relay receiver.

Further, 13 is a relay transmitter, and 14 is a relay station that performs a relay operation only while detecting a tone signal addressed to its own station, and a mobile receiver.

Furthermore, 2 is a plurality of l·− generated in the tone signal generating section.
3 is a distortion improvement means that superimposes a tone signal and suppresses a frequency component expressed by a linear combination using an integer of the frequency of the plurality of tone signals as a coefficient and applies it to the base transmitter; 4 is a moving unnecessary wave pass blocking filter that suppresses a frequency component represented by a linear combination using an integer of the frequencies of the tone signals as a coefficient, and 4 is a linear combination using an integer of the frequencies of the plurality of tone signals as a coefficient. This is a mobile unnecessary wave passage blocking filter that suppresses the expressed frequency components.

Then, a plurality of tone signals are simultaneously transmitted from the base station to cause a plurality of corresponding relay stations to perform relay operations simultaneously.

[Operation] The present invention provides two tones of frequency f and frequency f2 when transmitting a voice signal from a base station to a desired mobile station via, for example, No. 1 relay station and No. 2 relay station. The same operation as the conventional example can be performed using signals.

For this reason, the base transmitter simultaneously sends out a 1.-on signal of frequency [I and a 1.-on signal of frequency r, but the sum frequency (f, -1-f2) is transmitted at the same time. This component is generated and leaks into the audio band, degrading the S/N of the audio signal.

For example, if f+, 100 H2, fz, 15011z, the component of 2 (f + fz) or 3 (f+ + fz) becomes 500 Hz or 750 Hz and enters the audio signal. Note that the frequency component of the difference is less than 1oOHz and can be ignored. In addition, the human power level of the tone signal is approximately half that of the conventional example in the case of two waves.

Now, three means can be considered to improve this deterioration of the S/N ratio of the audio signal.

(2) Distortion improvement means is provided on the input side of the base transmitter to suppress unnecessary wave components other than the fundamental wave component of the two tone signals, such as higher-order waves and sum frequency components, on the transmitting side.

(2) A relay unnecessary wave passage blocking filter is provided on the output side of the relay receiver to block passage of unnecessary wave components 2 other than the fundamental wave component of the two tone signals, such as the sum frequency component.

(2) A mobile unnecessary wave passage blocking filter is provided on the output side of the mobile receiver to block passage of unnecessary wave components 2, such as the sum frequency component, other than the fundamental wave component of the two tone signals.

As a result, the unnecessary wave components of the two tone signals leaking into the audio signal output from the mobile receiver are suppressed and the S/N
is improved.

Furthermore, since n waves of tone signals are sufficient for simultaneously relaying operations from a base station to n relay stations, it is possible to minimize the number of signals used per system.

[Embodiment] Fig. 2 is a block diagram of the first embodiment of the present invention, Fig. 3 is a block diagram of the second embodiment of the present invention, and Fig. 4 is a block diagram of the third embodiment of the present invention. Show the diagram.

Here, combiner 21. The low-pass filter 22 is a component of the distortion improvement means 2, the band rejection filter 3132 is a component of the relay unnecessary wave passage prevention filter 3, and the band rejection filters 41 and 42 are the components of the mobile unnecessary wave passage prevention filter 4. The constituent parts are shown.

Also, the same reference numerals indicate the same objects throughout the figures. The operations shown in FIGS. 2 to 4 will be explained below.

Here, as in the conventional example, the relay stations are No., I relay station and N.
o, 2 relay stations, and when the base station sends out a tone signal with frequency f1, No. 1 relay station performs relay operation, and when it sends out a tone signal with frequency f2, No. 12 relay station performs relay operation. When a tone signal of frequency (L+fz) is transmitted, the No. 1 relay station and the No. 12 relay station simultaneously perform the relay operation.

Note that since the case of transmitting one tone signal has already been explained in the conventional example, the case of frequency (f→-rz) will be described.

First, in the base station, the combiner 21 combines the frequency f generated by the l-on signal generator (not shown) and the frequency f2.
・The synthesized 1 to -n signals of frequencies (f, +f2) are added to the low-pass filter 22 to remove unnecessary wave components other than the fundamental wave component, such as higher-order waves and the sum frequency. After suppressing the component, it is added to the modulation section 111.

Since an audio signal is also added here, after generating a modulated wave using the audio signal and the synthesized 1-tone signal, the transmitter 112 transmits the No.
Sends to relay station and N0 (12 relay stations).

No. 1 relay station and No. 2 relay station are each receiving section 1.
After the received signal is frequency-converted in 21123, it is amplified to a predetermined level and sent to demodulators 122 and 124. The demodulator demodulates the input signal and converts it into an audio signal and frequency (r).

The demodulated signal consisting of the composite 1.+f2) and -n signals is taken out and passed through the bandpass filter 5L 56 and the switch or
Add to SW2.

Therefore, the band-pass filter 5L 56 extracts the tone signal of frequency f,, f2 from the demodulated signal and sends it to the detector 5L.
Add to 57. The detectors 55 and 57 have detection outputs and switches SW, SW. Drive to turn on state (dotted line state)
Therefore, the audio signal is sent to the modulators 131 and 133 on the transmitting side.
The transmitter 132 and 134 then relay the signal to the mobile station at a predetermined transmission frequency and transmission power.

Next, FIG. 3 shows a relay unnecessary wave pass blocking filter 3L that suppresses unnecessary wave components other than the fundamental wave component of the composite tone signal.
32 is provided on the output side of the demodulator of the relay station.

Furthermore, in FIG. 4, the mobile station is provided with mobile unnecessary wave passage blocking filters 41 and 42 for suppressing unnecessary wave components other than the fundamental wave components of a plurality of tone signals.

By these methods, the number of tone signals used per system can be minimized without substantially degrading the S/N ratio of the audio signal.

12 is a relay receiver; 13 is a relay transmitter; [Effects of the Invention] As explained in detail above, according to the present invention, the number of tone signals used per system can be minimized. There is an effect.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the principle of the first to third embodiments of the present invention, FIG. 2 is a block diagram of the first embodiment of the present invention, and FIG. 3 is a block diagram of the second embodiment of the present invention. FIG. 4 is a block diagram of the third embodiment of the present invention, FIG. 5 is a conceptual diagram of a mobile system, and FIG. 6 is a block diagram of a conventional example. In the figure, 2 is a distortion improvement means, 3.4 is a band rejection filter, 11 is a base transmitter, and the block diagram of the next column is shown.

Claims (1)

[Claims] 1. A base station having a tone signal generator (15) and a base transmitter (11) capable of generating all set tone signals, a relay receiver (12), and a relay receiver (12); Transmitter (13)
a relay station that performs a relay operation only while detecting a tone signal addressed to the own station, and a mobile receiver (14), and is connected to the base station via the operating relay station. A wireless system comprising a mobile station that communicates with a base station, in which a plurality of tone signals generated in the tone signal generation section are superimposed on the base station, and a linear combination using an integer of the frequency of the plurality of tone signals as a coefficient. Distortion improvement means (2) is provided to suppress the frequency component expressed by and apply it to the base transmitter, and multiple tone signals are simultaneously transmitted from the base station and relayed simultaneously to the corresponding multiple relay stations. A relay method using tone squelch, which is characterized by causing 2. In the radio system according to claim 1, the relay station is provided with a relay unnecessary wave pass blocking filter (3) that suppresses frequency components expressed by linear combinations having integers of the frequencies of the plurality of tone signals as coefficients. 1. A relay system using tone squelch, characterized in that a plurality of tone signals are simultaneously transmitted from the base station to cause a plurality of corresponding relay stations to perform relay operations simultaneously. 3. In the wireless system according to claim 1, when transmitting a plurality of tone signals from the base station simultaneously and causing the corresponding plurality of relay stations to perform relay operations simultaneously, the frequency of the plurality of tone signals is transmitted to the mobile station. A mobile unnecessary wave pass blocking filter (4) that suppresses frequency components represented by a linear combination with an integer of . A relay method using a tone squelch, which is characterized by simultaneously performing a relay operation.