JPS60236332A - Mobile radio communication equipment - Google Patents

Abstract

PURPOSE:To attain communication with both mobile stations inside and outside a service area through a single radio communication equipment, by performing the multiple communication when the intensity of a received electric field is higher than a prescribed level and then the simple communication when said intensity is lower than the prescribed level. CONSTITUTION:When a mobile station is set within a service area A, a radio wave of a frequency fR sent from a base station 1 is received by a receiver via an antenna 44 and an antenna share unit 43. A detection circuit 45 detects the intensity of the received reception signal. Then a changeover switch SW47 is connected to the side (a) since the intensity of said signal is higher than a prescribed level. The mobile stations 11 and 12 perform the multiple communication with a transmitter 41 and a receiver 42 via the station 1 with transmission and reception frequencies fT and fR respectively. The communication is carried out with a mobile station 31 set in an out-of-service area B with a transmission frequency fT. In this case, a switch control circuit 46 is controlled by the output of the circuit 45 since the detection output of the circuit 45 is less than a prescribed level. Then an SW47 is switched to the side (b) and the frequency fT is converted into fR by a frequency conversion circuit 48 to secure the direct simple communication with the station 31. The SW47 is changed to the side (a) in a reception mode.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention enables not only communication with other mobile stations within the service area via a base station, but also direct communication with other mobile stations outside the service area with a single device. The present invention relates to a mobile radio communication device configured to have a mobile radio communication device.

In the domestic vessel communication system, as shown in FIG. 1, wireless communication between the mobile stations 11, 12 and the base station 1 within the service area A of the base station 1 is performed. Transmission from the mobile station 12 to the base station 1 is performed at the frequency fT, and reception from the base station 1 is performed at the frequency f (duplex communication). Wireless communication with the station 12 can be performed via the base station 1. Therefore, in service area A, mobile stations 11 and 12 have a transmitter 21 that transmits at frequency f, a receiver 22 that receives at frequency fR, and an antenna duplexer 23, as shown in FIG. It is sufficient to have a wireless device consisting of an antenna and antep 24.

However, the service area Δ of the base station 1 is within a radius of 50 to 1100 K, in which call quality can be ensured. Therefore, as shown in FIG. 1, a mobile station 31 located outside the service area
．． 32, call service by base station 1 is no longer available,
Communication between mobile station 31 and mobile station 32 via base station 1 is not possible.

For this reason, for example, in the case of mobile stations on ships operating in a convoy, it is inconvenient that they cannot communicate with each other outside the service area B. The only way to communicate with other mobile stations was to use radio equipment in other frequency bands. However, adding one more new radio device of another frequency band to directly communicate with each other in this way requires effective use of frequencies.
This was unfavorable from the perspective of capital investment.

The present invention was made to solve this problem, and it allows communication with other mobile stations via a base station within the service area Δ, and direct communication with other mobile stations operating outside the service area B. It is an object of the present invention to provide a mobile radio communication device that can perform both of the following with a single device.

Hereinafter, one embodiment of the present invention will be described based on the drawings.

FIG. 3 shows a mobile radio communication device provided in a mobile station according to an embodiment of the present invention. Showing configuration 4, a. There is.

In the figure, 41 is a transmitter that transmits at frequency fr, 42 is a receiver that receives at frequency fR, 43 is an antenna duplexer, and 44 is an antenna.
It is the same as shown in the figure.

45 is a detection circuit that outputs a detection signal when the strength of the received signal from the base station 1 of the receiver 42 falls below a predetermined value (the lowest value of the reception level from the base station 1 in the service area A).

46 is a switching control circuit which outputs a switching signal upon receiving the detection @ signal from the detection circuit 45.

/17 is used when transmitting and this switching control circuit 46
If no switching signal is output from contact a-a'
It is a change-over switch that is connected to the contact point AA= and changes from the contact point a-a= to the contact point bb- upon receiving a switching signal.

48 is the frequency f1 of the signal input from the antenna 44.
This is a frequency converter that converts into R.

Next, the operation of the above embodiment will be explained.

When the mobile station is within the service area A, the reception level of the reception 1142 which receives radio waves from the base station 1 is higher than a predetermined value, so the changeover switch is connected to the a-a= side. Since this state is the same as in Fig. 2, the transmission frequency f
Duplex communication is performed using the TN reception frequency fR. That is,
The transmission 1fi 41 can transmit to the base station 1 on one frequency, and the reception 142 can receive the same frequency from the base station 1, and the two mobile stations 11 and 12 within the service area A can transmit through the base station 1. communication.

When the mobile station leaves the service area B, the field strength of the radio waves from the base station 1 decreases, so that the reception level of the receiver 42 falls below a predetermined value. The detection circuit 45 detects this and outputs a detection signal. In response to this, the switching control circuit 46 switches the changeover switch 47 to the bb' side.

In this state, when there is a transmission of one frequency from another mobile station outside the service area B, the wave is received by the antenna 44, the frequency f is converted to fR by the frequency converter 48, and the wave is received by the receiver 42. Ru. When transmitting, selector switch 47 is set to a.
−a= side, and the frequency f is switched by the transmitter 41 to
Transmit with T.

In this way, the changeover switch 47 is automatically switched to the b-b- side in the out-of-service area B, so that a certain mobile station (for example, 31) in out-of-service area B uses the same transmission frequency for transmission to the base station 1. If it is transmitted using fr, other mobile stations (for example, 32) will automatically convert it to the same reception frequency image used for reception from base station 1 and receive it.
Direct communication between mobile stations is possible. Therefore, service area A
In this case, duplex communication is performed using the transmission frequency fTq and reception frequency width, and in the area B outside the service area, simplex communication is performed with the transmission frequency and reception frequency fTq.

Since the present invention is configured as described above, (1) communication with other mobile stations via base station 1 within service area △ and direct communication with other mobile stations outside service area B; Both can be done with one device.

(2) It is economical because it is only necessary to add a simple additional circuit to the conventional device.

(3) This is particularly advantageous for small ships because there is less space for installing antinos and less space for installing other equipment.

(4) The functions of the main service system (for example, secret communication circuit) can be used as is.

(5) Even if direct calls are added in B, which is outside the service area, there is no need to increase the frequency used, so radio waves can be used effectively.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a communication system of a mobile station, FIG. 2 is a block diagram showing a conventional mobile radio device, and FIG. 3 is a block diagram showing an embodiment of the present invention. 1... Base station, A... Service area,
B...Out of service area, 11.12...
Mobile station, 31.32... Mobile station, 41...
...Transmitter, 42...Receiver, 43...
・Antenna duplexer, 44...Antenna, 15・
...Detection circuit, 46...Switching control circuit,
47... Selector switch, 48... Frequency converter. Patent Applicant Anritsu Electric Co., Ltd. Nippon Telegraph and Telephone Public Corporation Agent Patent Attorney Makoto Hayakawa Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] (1) A transmitter for transmitting the frequency F1; a receiver for receiving the frequency F2; and a shared antenna that outputs the transmitting signal of the transmitter and inputs the received signal of the receiver. an antenna duplexer for input/output; a first state in which the received signal strength of the receiver exceeds a predetermined value;
a second state in which the received signal strength of the receiver is below a predetermined value; a detection means for detecting a second state in which the received signal strength of the receiver is below a predetermined value; a frequency converter for converting frequency F1 to frequency F2;
If the second state is detected, the antenna and the antenna duplexer are directly connected to perform duplex communication, and if the detection means detects the second state, the antenna and the antenna duplexer are connected only during reception. A mobile radio communication device comprising: a switching device for switching to perform simplex communication with the frequency converter interposed between the antenna duplexer and the antenna duplexer; (2) The detection means is a mobile radio communication device based on an S/N value of a received signal or an electric power.