JPH0453131B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a wireless communication system between a plurality of fixed stations and a mobile station.

Conventionally, when communicating between multiple fixed stations and a mobile station, the fixed station sends information for starting the switch only when it can receive the transmitted wave from the mobile station at a certain strength or higher. The information is sent to the exchange, which receives this information and activates the exchange to configure a communication line.

For example, FIG. 1 is a block diagram of a portion of a conventional fixed station receiver that transmits this information.
The reception input input from the intermediate frequency stage of the receiver to terminal 1 is converted to an intermediate frequency, amplified by amplifier 2, and further detected by detector 3, and its DC output is compared with reference voltage Es by comparator 4. If the comparison input is higher than the reference level, the information is sent to the exchange via the terminal 5 connected to the output of the comparator 4.

In this way, the fixed station receiver transmits information only according to the received input level, so normally between adjacent fixed stations, the transmitting and receiving frequency is changed for each fixed station, so that it can transmit information in a zone other than the one where the mobile station is located. The received electric field of the fixed station is prevented from exceeding a specified value, and information for starting the exchange is not sent.

However, in places with complex topography, where more fixed stations are placed to eliminate dead areas, the transmitted waves from the mobile station may be received by a fixed station other than the normal communication partner, and the received electric field may exceed the specified value. Therefore, information for starting the exchange may be sent from a source other than the fixed station that is the normal communication destination. At this time, there was an inconvenience that caused erroneous connection or double connection of the communication line. Furthermore, in order to prevent this by changing the transmitting and receiving frequencies, a very large number of frequencies would be required, which is disadvantageous in terms of effective frequency utilization.

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and to provide a wireless communication system in which information for activating an exchange is sent only from a fixed station that is a normal communication destination.

For this purpose, in the wireless communication system according to the present invention, the mobile station transmits a signal corresponding to the identification signal sent from the fixed station, and the received electric field level at the fixed station is equal to or higher than a specified value, and the mobile station The present invention is characterized in that it is configured to send information for activating the exchange to the exchange when the signal is received from the exchange.

Hereinafter, the present invention will be explained by examples with reference to the drawings.

FIG. 2 is a block diagram of main parts of a mobile station according to an embodiment of the present invention. In FIG. 2, an identification signal sent from a fixed station is demodulated by a demodulator of a receiver of a mobile station and inputted to an input terminal 7. Wave devices 8, 9, and 10 are connected to this input terminal 7. The wave transmitters 8, 9, and 10 wave identification signals of frequencies ₁ , ₂ , and ₃ , respectively, corresponding to the modulation frequencies ₁ , ₂ , and ₃ of the identification signals sent from the fixed station. Further, each output of the wave detectors 8, 9, and 10 is connected to each input of a wave detector 12, 13, and 14 that detects this identification signal. Furthermore, this detector 12,1
The inputs of oscillators 16, 17, and 18, which operate based on the detection outputs, are connected to the outputs of oscillators 3 and 14, respectively. These oscillators 16, 17, and 18 output signals at different modulation frequencies ₁ ', _2' , and _3' corresponding to the modulation frequencies ₁ , ₂ , and ₃ to output terminals 20, respectively.
Send to. This output terminal 20 is connected to the modulation input of the modulator of the mobile station transmitter.

FIG. 3 is a block diagram of the main parts of a fixed station that transmits and receives signals of modulation frequency ₁ according to an embodiment of the present invention. In FIG. 3, each symbol corresponds to each symbol in FIG. 1, respectively.

The characteristic configuration of this embodiment is that a signal from a demodulator of a receiver provided at a fixed station is given to a wave detector 22 via a terminal 21, and this wave output is transmitted to a wave detector 22.
3 is detected and connected to one input of an AND circuit 25, the other input of this AND circuit 25 is connected to the comparison input of the comparator 4 shown in FIG. 1, and the output of this AND circuit 25 is connected to the exchange It is connected to terminal 5 for sending out to the side.

The fixed station also has a modulation frequency unique to this fixed station.
An oscillator 26 is provided which oscillates ₁ and the output of this oscillator 26 is connected to terminal 2 which is led to the modulator of the transmitter.
Connected to 7. The wave transmitter 22 is configured to wave only a signal having a modulation frequency ₁ ' corresponding to the modulation frequency ₁ specific to this fixed station.

With such a configuration, the identification signal sent from the fixed station to the demodulator of the receiver of the mobile station is demodulated by the demodulator, passes through either wave generator 8, 9, or 10 depending on the frequency, and is sent to the wave detector. The wave is detected by 12, 13, or 14, and the output is used to generate the oscillator 1.
6, 17, or 18 and is sent to the transmitter's modulator. i.e. the modulation frequency from the fixed station
Different modulation frequencies corresponding to ₁ , ₂ , or ₃
It will be sent in ₁ ′, ₂ ′, or ₃ ′.

Also, the signal from the demodulator of the receiver of the fixed station passes through the waver 22 as shown in FIG.
Only the frequency ₁ ' that matches the frequency ₁ ' of 2 is detected by the detector 23, and its output is sent to the AND circuit 25. In addition, the received input from the mobile station is converted to an intermediate frequency, and is detected via an amplifier 2 and a wave detector 3 via a terminal 1, and its DC output is transmitted to a comparator 4.
It is compared with the reference voltage Es, and when it is higher than the reference level, it is sent to the AND circuit 5. The AND circuit 25 transmits information when the signal frequency matches ₁ ' and the reception level is above a specified value. The oscillator 26 modulates the fixed station transmission wave with a frequency ₁ unique to the fixed station and transmits it to the mobile station.

In other words, information for starting the switch can be sent only when the same fixed station receives the output of a mobile station that has received a signal with a modulation frequency of ₁ from this fixed station. Even if a radio wave is received, information for activating the exchange is not sent out, and erroneous connections and double connections of communication lines can be prevented.

In addition, in the above embodiment, a case was explained in which the transmission waves of fixed stations and mobile stations are modulated with tone frequencies and selected and received by the receiver side waver. The present invention is not limited to this signal; for example, the transmission and reception of digital signals of several bits can be carried out in a similar manner.

As described above, according to the present invention, by setting individual identification signals to a plurality of fixed stations and configuring the mobile station to send out this identification signal to activate the switching equipment of the fixed station, it is possible to A high-quality wireless communication system can be obtained in which incorrect connection or double connection of communication lines can be prevented in cases of complicated communication, and information for starting the exchange can be sent only from fixed stations that are normal communication destinations.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of a conventional fixed station receiver. FIG. 2 is a block diagram of main parts of a mobile station according to an embodiment of the present invention. FIG. 3 is a block diagram of main parts of a fixed station according to an embodiment of the present invention. 1...terminal, 2...amplifier, 3...detector, 4
... Comparator, 5 ... Terminal, 7 ... Input terminal, 8,
9, 10... wave generator, 12, 13, 14... detector, 16, 17, 18... oscillator, 20... output terminal, 21... terminal, 22... wave detector, 23...
wave generator, 25...AND circuit, 26...oscillator,
27...Terminal.

Claims (1)

[Claims] 1. In a mobile radio communication system in which a plurality of fixed stations are arranged and a mobile station is configured to set up a communication line with one of the fixed stations, prior to setting up the communication line, The fixed station sends out an identification signal unique to that fixed station, and the mobile station that receives this identification signal sends out a signal corresponding to the identification signal converted from this identification signal, and this signal is received by the fixed station. When the received electric field level of this signal is equal to or higher than a specified value, and the signal is identified as a corresponding signal obtained by converting the identification signal of the own station, the communication line is set up. Communication method.