JP3457255B2 - Mobile wireless communication device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile radio communication apparatus that performs switching between duplex communication, semi-duplex communication and simplex communication without switching. 2. Description of the Related Art Conventionally, as a radio communication system used in a fire department, a communication system based on simplex (simplex system) is used. That is, as shown in FIG. 5, between a base station radio 1 installed in a base station such as a fire station and mobile radios 2a and 2b for a mobile station mounted in a fire truck, or a mobile radio 2a. , 2b are alternately transmitted and received using one frequency f1. In the simplex communication system, when communication is performed between mobile stations, that is, between the mobile radios 2a and 2b, when the distance between the two is short and within a communicable range, direct communication between the two is performed. It is possible to However, if the distance between the mobile stations is large and out of the communicable range, direct communication cannot be performed. Therefore, the mobile wireless devices 2a and 2b
A method of requesting a base station to transmit a message to a partner mobile station through the base station radio 1 is adopted. [0004] As described above, the conventional communication system has a problem that if the distance between the mobile stations is so large that the mobile stations are out of the communicable range, communication between the mobile stations becomes impossible. In this case, it is possible to request a message to the other mobile station through the base station, but information transmission by the message causes a delay and information content is insufficient. Particularly when a fire truck is dispatched, emergency contact is often required, and improvement is desired. SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and enables communication through a base station and stable communication even when the distance between mobile stations is far from the communication range. It is an object of the present invention to provide a mobile wireless communication device that performs the following. SUMMARY OF THE INVENTION The present invention provides a simplex system for wireless communication between mobile stations, and a duplex or semi-duplex system between a mobile station and a base station. A wireless communication device for performing wireless communication according to (1), a transmitting / receiving antenna, a first duplex filter connected to the antenna,
A first receiver that receives a signal of a first frequency transmitted from the base station through the first duplex filter, a transmitter that transmits a signal of a second frequency, and A second receiver for receiving the transmitted second frequency signal via the first duplex filter; and a first switch for connecting the transmitter and the second receiver to the first duplex filter. And a diversity receiving antenna, a second duplex filter connected to the antenna, and a second duplex filter for transmitting a signal of a first frequency transmitted from the base station. And a second receiver transmitted from another mobile station.
From a fourth receiver that receives a signal having the frequency of the second through the second duplex filter, and a second press-talk switch that turns on / off the fourth receiver and the duplex filter. And a diversity receiving circuit. Embodiments of the present invention will be described below with reference to the drawings. (First Embodiment) FIG. 1 is a basic configuration diagram of a mobile radio communication system according to the present invention. In FIG. 1, reference numeral 10 denotes a base station, on which a base station radio 11 is installed. Reference numerals 12a and 12b denote mobile stations of mobile vehicles and the like, and the mobile stations 12a and 12b are provided with mobile radio devices 13a and 13b, respectively. The base station radio 11 and the mobile radios 13a and 13b each have a diversity receiving function. The base station radio 11 includes a receiver for receiving the signal of the frequency f1 and a transmitter for transmitting the signal of the frequency F1, has a function of transmitting and receiving information as the base station 10, and has the functions of the mobile radios 13a and 13b. Has a relay function of receiving the signal of the frequency f1 sent from, converting it to the signal of the frequency F1 and transmitting the signal. The mobile radios 13a and 13b include a receiver for receiving a signal of the frequency F1 transmitted from the base radio 11, and a transmitter for transmitting a signal of the frequency f1.
The base station radio 11 has a duplex or semi-duplex communication function using signals of frequencies F1 and f1,
The mobile radios have a simplex communication function using a signal of frequency f1. The duplex system is a system in which transmission and reception are performed between the base station radio 11 and the mobile radio 13a or the mobile radio 13b by simultaneously using two frequencies F1 and f1. The semi-duplex system uses the base station radio 11 and the mobile radio 13a or the mobile radio 13b.
And transmission and reception using the two frequencies F1 and f1 alternately. The simplex method uses a frequency f between the mobile radio 13a and the mobile radio 13b.
In this method, transmission and reception are performed by alternately using one wave. As described above, duplex or semi-duplex communication is performed between the base station radio 11 and the mobile radio 13a or 13b using the frequencies F1 and f1. Mobile radio 13a and mobile radio 13
A simplex communication is performed between the terminal b and the terminal b. Therefore, it is possible to switch between the duplex communication method, the half-duplex communication method and the simplex communication method without switching. Then, the base station 10 and the mobile station 12a,
When communication is performed with the mobile station 12b or between the mobile stations 12a and 12b, the transmitting side first calls the other station by the station name or the like, and communication is started in a form in which the station receiving the call responds. Now, for example, from the mobile station 12a to the mobile station 12b
, The signal of the frequency f1 output from the mobile radio device 13a of the mobile station 12a is directly sent to the mobile radio device 13b, and is transmitted via the base radio device 11. It is sent to the wireless device 13b. In this case, the base station radio 11 converts the signal of the frequency f1 transmitted from the mobile radio 13a into a signal of the frequency F1 and transmits the signal of the frequency F1 to the mobile radio 13b. Mobile radio 13b
Is the frequency f directly transmitted from the mobile radio 13a.
1 and a signal of the frequency F1 transmitted via the base station radio 11 are received by different receivers, and the received signals are demodulated and combined to drive one receiver. The mobile station 12b responds by receiving the call from the partner station received by the mobile radio 13b. As described above, the mobile radios 13a, 13b
When communication is performed between the mobile radio devices 13a and 13b, there is a communication route directly connecting the mobile radio devices 13a and 13b and a communication route via the base radio device 11. For this reason, the mobile radios 13a, 13b
It is possible to communicate via a communication path via the base station radio 11 even if the distance between them is far enough to make communication impossible. Next, a specific configuration example of the base station radio 11 and the mobile radios 13a and 13b will be described with reference to FIG. The base station radio 11 includes an F1 transmitter (F1 · T) 21 for transmitting a signal of the frequency F1, and a frequency f.
F1 receiver (f1 · R) 22 for receiving signal 1 and diversity f1 receiver 2 for receiving signal of frequency f1
3, duplex filter 24, transmitting / receiving antenna 2
5. Diversity receiving antenna 26 and selection switch 2
7 is provided. The F1 transmitter 21 and f1 receiver 22
Is an antenna 25 through a duplex filter 24.
Connected to. The F1 transmitter 21 modulates a carrier having a frequency F1 with an audio signal input from a transmitter MIC, and modulates the carrier with a frequency
Send from. The signal of the frequency f1 received by the antenna 25 is sent to the f1 receiver 22 via the duplex filter 24. The f1 receiver 22 demodulates the received signal to convert the F1 transmitter 21 and the selection switch 27.
To enter. The duplex filter 24 has a function of F1
The signal of the frequency F1 output from the transmitter 21 is output only to the antenna 25 side to prevent the signal from entering the f1 receiver 22.
1 is output only to the f1 receiver 22 side,
1 has a filter characteristic for preventing the signal from flowing into the transmitter 21. Further, the diversity f1 receiver 23
The signal of the frequency f1 is received via the diversity receiving antenna 26, demodulated, and input to the selection switch 27. In this case, the diversity f1 receiver 23 shifts the phase of the output signal with respect to the f1 receiver 22 to facilitate diversity reception. The selection switch 27 compares the received signals of the f1 receivers 22 and 23, alternately switches the received signal having a higher level, outputs the signal to the receiver SP, and performs diversity reception with less level fluctuation. On the other hand, the mobile radios 13a and 13b are provided with an F1 receiver (F1.R) 3 for receiving a signal of the frequency F1.
1. f1 transmitter for transmitting a signal of frequency f1 (f1 ·
T) 32, an f1 receiver (f
1 · R) 33, duplex filter (DUP) 3
4. A transmission / reception circuit comprising a press-talk switch SW1 for switching between the f1 transmitter 32 and the f1 receiver 33 and connecting to the duplex filter 34, and a transmitting / receiving antenna 35 connected to the duplex filter 34, and having a frequency F1 F1 receiver (F1
R) 36, f1 receiver (f1 · R) 37 for receiving a signal of frequency f1, the F1 receiver 36, f1 receiver 3
Antennas 3 connected respectively to the antennas 7
8a, 38b, and a diversity receiving circuit including a press talk switch SW2 for turning on / off between the f1 receiver 37 and the diversity receiving antenna 38b. The above-mentioned press talk switches SW1, SW2
Is a switch (push button switch) for antenna switching that operates in conjunction with it, and is normally connected to the f1 receivers 33 and 37 side. The signals received and demodulated by the F1 receivers 31 and 36 are input to a selection switch 39, and the signals received and demodulated by the f1 receivers 33 and 37 are output to a selection switch 40. Is entered. The diversity F1 receiver 36, f1
The receiver 37 is connected to the F as in the case of the base station radio 11.
The phase of the output signal is shifted with respect to each of the 1 receiver 31 and the f1 receiver 33 to facilitate diversity reception. Then, the selection switch 39 switches the F1 receivers 31, 36.
Of the f1 receivers 33 and 37, and alternately switches the received signal of the higher level by comparing the received signals of the f1 receivers 33 and 37. The output is switched to the combiner 41 to perform diversity reception with little level fluctuation. The synthesizer 41
Synthesizes the signal selected on the selection switch 39 and inputs it to the receiver SP. The audio signal from the transmitter MIC is input to the f1 transmitter 32. In the above configuration, the mobile radio 13
In the normal state where the switches SW1 and SW2 are not operated, the F1 receiver 31 and the f1 receiver 33 are connected to the duplex filter 34, and
The receiver 37 is connected to the diversity receiving antenna 38b, and the f1 transmitter 32 is separated from the duplex filter 34. Therefore, the mobile radios 13a, 1
3b is the frequency F1 sent from the base station radio 11
Signal and frequency f sent from another mobile radio
1 can be received. In this state, diversity reception for the frequency F1 is performed by the antennas 35, 38a, the F1 receivers 31, 36, and the selection switch 39, and the antennas 35, 38b, f1
Frequency f1 by receivers 33 and 37 and selection switch 40
Is performed for diversity reception. Then, when the user sets the switches SW1 and SW2
When the switch is pressed, the switch SW1 is switched from the f1 receiver 33 to the f1 transmitter 32, the f1 transmitter 32 is connected to the duplex filter 34, the switch SW2 is turned off, and the f1 receiver 37 is connected to the diversity receiving antenna. 38b. Therefore, in this state, the mobile wireless devices 13a and 13b are in a state where transmission at the frequency f1 and reception at the frequency F1 can be performed simultaneously. At this time, the f1 receivers 33 and 37 are set to the switches SW.
1, since it is disconnected from the circuit by SW2, reception for frequency f1 is not performed. In the above state, when an audio signal is input from the transmitter MIC to the f1 transmitter 32, the f1 transmitter 32
The carrier wave of the frequency f1 is modulated by the input audio signal and transmitted through the duplex filter 34 and the antenna 35. In addition, for signals of frequency F1 transmitted from base station radio 11, antennas 35 and 38
a, F1 receivers 31 and 36 and diversity switch 39 perform diversity reception, and the demodulated signal selected by selection switch 39 is input to receiver SP via combiner 41. Now, for example, the mobile radio 1 of the mobile station 12a
When communication is performed from the mobile wireless device 13a to the mobile wireless device 13b of the mobile station 12b, the switches SW1, SW
After switching to the transmission mode by pressing 2, a voice is input from the transmitter MIC. The voice signal input from the transmitter MIC is modulated by the f1 transmitter 32 and transmitted as a radio signal of the frequency f1 via the duplex filter 34 and the antenna 35. On the other hand, the mobile wireless device 13b
It directly receives the signal f1 transmitted from the mobile wireless device 13a and receives the signal F1 transmitted via the base wireless device 11. In this case, the mobile radio 13
b is received by the f1 receivers 33 and 37 for the signal f1, received by the F1 receivers 31 and 36 for the signal F1, and input to the receiver SP via the selection switches 39 and 40 and the synthesizer 41. . When the distance between the mobile radio device 13a and the mobile radio device 13b is within a communication range, a signal transmitted from the mobile radio device 13a via the base radio device 11 is transmitted. F1 can be received by the mobile wireless device 13b. When the moving vehicle is a fire truck, the vehicle moves around a fire station, which is a base station.
Even if the distance between the mobile stations 13b is large enough to make communication impossible, the mobile radios 13a, 13b and the base station radio 11 have a communicable distance. Therefore, even if the distance between the mobile radios 13a and 13b is within a communication-disabled range within the normal activity range of the fire truck, communication can be performed via the base radio 11. (Second Embodiment) Next, a second embodiment of the present invention will be described. According to the first embodiment, communication between the base radio 11 and the mobile radios 13a and 13b, direct communication between the mobile radios 13a and 13b, and communication via the base radio 11 Can be performed.
However, the mobile wireless devices 13a and 13b require two diversity receiving antennas 38a and 38b in addition to the normal wireless transmitting and receiving antenna 35, and a total of three antennas need to be mounted on the mobile vehicle. . The above three antennas are mounted on the roof of a moving vehicle, but it is very difficult to mount them at regular intervals because the space on the roof is limited. Therefore, it is desirable to minimize the number of antennas mounted on the moving vehicle. Therefore, in the second embodiment, one antenna is used in addition to the normal wireless transmitting / receiving antenna.
This is to achieve the initial purpose only by providing the diversity receiving antenna. FIG. 3 is a configuration diagram of a wireless communication system according to a second embodiment of the present invention. In the second embodiment,
The diversity receiving antenna 38 in each of the mobile radio devices 13a and 13b is connected to a two-divider (DEV) 51, one of the divided outputs of the two-divider 51 is input to the F1 receiver 36, and the other divided output is switched. This is configured to be input to the f1 receiver 37 via SW2. Other configurations are the same as those in the first embodiment, and thus the same reference numerals as those in FIG. 2 are used and the detailed description is omitted. In the above configuration, the mobile radio 13
When the switches SW1 and SW2 in the switches 13a and 13b are not pressed, the signals of the frequencies F1 and f1 are received by the diversity receiving antenna 38. The above antenna 3
8, the signal of frequency F1 is input to the F1 receiver 36 via the two divider 51, and the signal of frequency f1 is input to the f1 receiver 3 via the two divider 51 and the switch SW2.
7 is input. Accordingly, the F1 receivers 31 and 36 perform diversity reception on the signal of the frequency F1, and the f1 receivers 33 and 37 perform diversity reception on the signal of the frequency f1. When the switches SW1 and SW2 are pressed, the switch SW1 switches from the f1 receiver 33 to the f1 transmitter 32, and the f1 receiver 37 is disconnected from the two distributor 51. Accordingly, the transmission of the frequency f1 is performed by the f1 transmitter 32 and the F1 receiver 3
1 and 36, diversity reception for frequency F1 is performed. As described above, by connecting the F1 receiver 36 and the f1 receiver 37 for diversity reception to the diversity reception antenna 38 via the two divider 51,
Diversity reception can be performed by the antenna 38. Therefore, as the mobile wireless devices 13a and 13b,
The purpose can be achieved by installing one diversity reception antenna 38 in addition to the transmission / reception antenna 35. (Third Embodiment) Next, a third embodiment of the present invention will be described. According to the second embodiment, the mobile wireless devices 13a and 13b can achieve the initial purpose only by providing one diversity receiving antenna 38 in addition to the normal wireless transmitting / receiving antenna 35, The burden on the mobile station can be reduced. However, in the second embodiment, the signal received by the diversity receiving antenna 38 is divided into
, The received signal receives the insertion loss of the two-way splitter 51. The two divider 51 has a loss of about 3.5 dB, and the diversity gain is reduced by the loss. When the diversity gain is reduced, the communication range of the mobile radio devices 13a and 13b is narrowed. Therefore, it is not desirable to reduce the diversity gain. Therefore, in the third embodiment, even when one diversity receiving antenna is shared, the configuration is such that the insertion loss in distributing the received signal can be reduced as much as possible. FIG. 4 is a configuration diagram of a wireless communication system according to the third embodiment of the present invention. In the third embodiment,
In the mobile wireless devices 13a and 13b, a duplex filter 52 is used in place of the splitter 51 in the second embodiment. Other configurations are the same as those of the above-described first and second embodiments.
3 are given the same reference numerals as in FIG. 3 and detailed description is omitted. The duplex filter 52 outputs the signal of the frequency F1 received by the diversity receiving antenna 38 only to the F1 receiver 36 side to prevent the signal from entering the f1 receiver 37, and suppresses the signal of the frequency f1. The filter has a filter characteristic of outputting to only the f1 receiver 37 side and preventing the sneaking into the F1 receiver 36. The insertion loss of the duplex filter 52 is about 1.0 dB.
This is an extremely small value as compared with the insertion loss of 3.5 dB of the two-way divider 51 shown in the second embodiment, and the decrease in the diversity gain can be remarkably reduced. Further, when the mobile radios 13a and 13b are transmitting signals of the frequency f1 by pressing the switches SW1 and SW2, the duplex filter 52 controls the divergence from the diversity receiving antenna 38 to the F1 receiver 36. Since the blocking can be prevented, the influence of sensitivity suppression due to the spread of the sideband of the F1 receiver 36 can be removed, and the reception characteristics with respect to the frequency F1 can be kept good. The base station radio 11 and the mobile radios 13a and 13b in the above embodiment may of course be constituted by either digital circuits or analog circuits. In the above embodiment, the case where two mobile radios 13a and 13b are used has been described.
Even when a large number of mobile radios are used, the present invention can be implemented in the same manner as in the above embodiment. As described in detail above, according to the present invention, in a mobile radio, one diversity receiving antenna is shared by two diversity receivers. Only by providing one diversity receiving antenna in addition to the above, diversity reception can be performed, and installation of the antenna becomes extremely easy. Also, since one diversity receiving antenna and two diversity receivers are coupled by a duplex filter, the antenna can be shared with a very small insertion loss, and the diversity gain is significantly reduced. Can be reduced. Further, when the mobile radio is transmitting a signal of frequency f1, the duplex filter can prevent the transmission signal from diverting from its own diversity receiving antenna to the receiver, and the sensitivity due to the spread of the sideband of the receiver. The effect of suppression can be removed to maintain good reception characteristics.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram showing a basic configuration of a wireless communication system according to a first embodiment of the present invention. FIG. 2 is an exemplary view showing a specific circuit configuration of the wireless communication system in the embodiment. FIG. 3 is a diagram illustrating a circuit configuration of a wireless communication system according to a second embodiment of the present invention. FIG. 4 is a diagram illustrating a circuit configuration of a wireless communication system according to a third embodiment of the present invention. FIG. 5 is a diagram showing a basic configuration of a conventional wireless communication system. [Description of Signs] 10 Base station 11 Base transceiver 12a, 12b Mobile station 13a, 13b Mobile transceiver 31, 36 F1 receiver 32 f1 transmitter 33, 37 f1 receiver 34, 52 Duplex filter 35 Transmission / reception antenna 38, 38a, 38b Diversity receiving antennas 39, 40 Selection switcher 41 Combiner

Claims (1)

(57) [Claims] [Claim 1] Mobile radio that performs wireless communication by a simplex method between mobile stations and performs wireless communication by a duplex or semi-duplex method between a mobile station and a base station. In the communication device, a first transmitting / receiving antenna, a first duplex filter connected to the antenna, and a first frequency signal received from the base station via the first duplex filter. A receiver for transmitting a signal of the second frequency, and a second transmitter for transmitting a signal of the second frequency.
A second receiver for receiving the signal of the frequency of the second through the first duplex filter, a first pre-stalk switch for switchingly connecting the transmitter and the second receiver to the first duplex filter, , A diversity receiving antenna, a second duplex filter connected to the antenna, and a signal of a first frequency transmitted from the base station via the second duplex filter. A third receiver, a fourth receiver for receiving a signal of a second frequency transmitted from another mobile station via the second duplex filter, and the fourth receiver and the duplex filter A diversity receiving circuit comprising a second press-talk switch for on / off connection between the mobile telephone and a mobile telephone. Wireless communication device.