JP2665132B2 - Multi-channel access wireless telephone device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an MCA (multi-channel access) type radio telephone apparatus.

[0002]

2. Description of the Related Art A radio telephone system of the MCA system uses a channel assigned by a base station among a plurality of communication channels in data communication with a base station on a control channel in a service area managed by a base station as a repeater. Wireless communication between a plurality of mobile stations via a base station. The radio telephone device used in the mobile station has a call operation mode, as described above, having a repeater mode for radio communication via the base station and a direct mode for direct radio communication between mobile stations. I have. The direct mode is provided for wireless communication between mobile stations outside the service area.

[0003]

For example, when both mobile stations A and B making a call are located in the same service area, the call can be made in the repeater mode. However, if one or both of the mobile stations A and B are located outside the service area, the mobile stations A and B
In both cases, there is a problem that a call cannot be made unless the user switches the call operation mode to the direct mode.

When the mobile stations A and B are located in the same service area, radio waves are transmitted between one of the mobile stations A and B and the base station due to an obstacle such as a building. If it is interrupted, the call cannot be made in the repeater mode even if the users of the mobile stations A and B can see each other. In this case, even if a call is possible in the direct mode, no call is made in the direct mode for both mobile stations A and B unless the user switches the operation mode to the direct mode.

An object of the present invention is to provide an MCA-type radio telephone apparatus which can automatically switch the operation mode to the direct mode when a call in the repeater mode is impossible.

[0006]

According to the present invention, there is provided an MCA-type radio telephone apparatus for communicating data between a base station and a base station on a control channel by using a communication channel designated by the base station among a plurality of communication channels. Multi-channel having a repeater mode in which a call can be made with a partner station through a call channel and a direct mode in which a call can be made directly with the partner station on a call channel different from that of the repeater mode as a call operation mode An access-type radio telephone device, comprising: a scan control unit configured to perform a scan mode in which a reception state on a control channel in a repeater mode and a reception state on a communication channel in a direct mode are alternately repeated at predetermined intervals; When a signal is received on the mode control channel, Repeater mode control means for starting operation in the data mode, and direct mode control means for starting operation in the direct mode when a signal is received on the direct mode communication channel by the scan control means. Is characterized by activating the repeater mode control means or the direct mode control means when a signal having an electric field strength not lower than a predetermined level is continuously received for a predetermined time or more.

[0007]

In the MCA radiotelephone apparatus of the present invention, the reception state on the control channel in the repeater mode and the reception state on the communication channel in the direct mode are alternately repeated at predetermined intervals. The operation in the repeater mode is started when the signal having the electric field strength equal to or higher than the predetermined level is continuously received for the predetermined time or longer, while the signal having the electric field strength equal to or higher than the predetermined level in the direct mode communication channel is used for the predetermined time. When the data is continuously received, the operation in the direct mode is started.

[0008]

Embodiments of the present invention will be described below in detail with reference to the drawings. In the MCA wireless telephone device according to the present invention shown in FIG. 1, the antenna 1 is a transmitting / receiving antenna and is connected to one of the receiving unit 3 and the transmitting unit 4 via the antenna switch 2. The selection of the antenna switch 2 on the receiving unit 3 side is in a steady state. In the receiving unit 3, the high-frequency signal, which is the signal received from the antenna switch 2, is band-limited by the band-limiting filter 5 and supplied to the high-frequency amplifier 6. The signal amplified by the high-frequency amplifier 6 is band-limited by the band-limiting filter 7 and then supplied to the first frequency mixer 8. First
The frequency mixer 8 mixes the supplied high-frequency signal with the first local oscillation signal from the VCO 9 to generate a first intermediate frequency signal. The VCO 9 is connected to a PLL synthesizer 10 for performing feedback control of the oscillation frequency of the VCO 9.

The first intermediate frequency signal is supplied to a second frequency mixer 12 via a first intermediate frequency band limiting filter 11. The second frequency mixer 12 mixes the supplied first intermediate frequency signal with the second local oscillation signal from the second local oscillator 13 to generate a second intermediate frequency signal. Second frequency mixer 1
2 is supplied to the demodulator 15 via the second intermediate frequency band limiting filter 14. The demodulator 15 detects the frequency of the second intermediate frequency signal and demodulates the audio signal and the control signal. The audio signal is amplified by the audio frequency amplifier 16 and then supplied to the speaker 17. The control signal is MSK (Mi
After being demodulated into an NRZ control signal, the signal is supplied to the controller 19.

On the other hand, in the transmitting section 4, the audio signal output from the microphone 21 is amplified by the microphone amplifier 22 and supplied to the VCO 23. A control signal modulator 31 is connected to the VCO 23, and the control signal modulator 31 MSK modulates the NRZ format control signal output from the controller 19. The VCO 23 frequency-modulates the audio signal and the control signal after the MSK modulation, and oscillates under the control of the PLL synthesizer 24. The modulated oscillation signal output from the VCO 23 is amplified by the preamplifier 25 and further amplified by the power amplifier 26 to become a transmission signal. This transmission signal is supplied to the antenna 1 via the antenna switch 2.

The controller 19 comprises a microcomputer, and controls the synthesizers 10 and 24 so as to generate control signals and change the oscillation frequencies of the VCOs 9 and 23 to set the reception frequency and the transmission frequency. The microphone 21 is provided with a press talk switch (not shown), and when the press talk switch is turned on, the antenna switch 2 is switched to the transmission section 4 side by the controller 19, and the apparatus enters a transmission state. During this transmission, the tone signal from the tone signal generator 28 is superimposed on the audio signal of the microphone 21 after being amplified by the microphone amplifier 22 and supplied to the VCO 23. The tone signal generator 28 generates a tone signal having a frequency according to a command from the controller 19.

The second intermediate frequency band limiting filter 14 is connected to a level detection circuit 27 for detecting the electric field strength of the received signal from the second intermediate frequency signal level. The level detection circuit 27 supplies a reception level signal indicating the detected electric field strength to the controller 19. In addition, a signal detection circuit 30 is connected to the output of the demodulator 15 via a band-pass filter (BPF) 29 to detect the tone signal during reception. The band-pass filter 29 has a pass band in the frequency band of the tone signal, and the signal detection circuit 30 supplies a tone detection signal to the controller 19 when an output signal is detected from the band-pass filter 29.

In such a radio telephone apparatus, a control channel for transmitting / receiving a control signal to / from a base station, a plurality of communication channels in a repeater mode, and at least one communication channel for a direct mode are used as channels. Is provided. In this embodiment, the communication channel for the direct mode is one channel.

The control signal comprises a bit synchronization signal, a frame synchronization signal and data as shown in FIG. The bit synchronization signal is a signal in which 1 and 0 are alternately arranged by 16 bits. Further, the data differs in length (144 bits for the base station and 82 bits for the mobile station) and content between the base station and the mobile station, but the command code, system code, power It includes codes such as a supervisory code and a group code, and the data for the base station includes a channel code for specifying a communication channel.

[0015] When the power to the apparatus is turned on, the controller 19 first, as shown in FIGS. 3 and 4, the mode change flag F _M is initialized to 0 (step S1), the direct mode call reception frequency It controls the PLL synthesizer unit 10 in order to set the frequencies F ₁ channel (step S2). Thus, the standby mode is set for the communication channel in the direct mode. Next, it is determined whether or not the electric field strength of the received signal is equal to or higher than a predetermined level according to the output received level signal of the level detection circuit 27 (step S3). If the electric field strength of the received signal is smaller than the predetermined level, it is determined whether or not the standby operation state on the current channel has passed 250 msec (step S4). If the standby operation time does not reach 250 msec, it is determined whether or not the call is a call request in the direct mode (step S5). If there is no call request in the direct mode, the process returns to step S3. If there is a call request in the direct mode by the user's operation, a call operation is performed (step S6). Calling operation the antenna switch 2 is in the selected state of the transmission unit 4 side by the ON operation of the press-talk switch, radio waves are transmitted from the antenna 1 at frequencies F ₁ of the communication channel. Performing the calling operation in the direct mode can be set by a user's predetermined key operation. After the end of the calling operation, the process returns to step S3 to perform a standby operation.

[0016] On the other hand, whether in the case where a state for waiting time reaches the 250msec since the current channel between the 250msec was no signal that can be received by the electric field intensity equal to or greater than the predetermined level, the mode switching flag F _M is zero Is determined (step S7). Since mode change flag F _M is initially set to 0 at power up, if F _M = 0, it sets the mode change flag F _M to 1 (step S8), and the reception frequency of the control channel of the repeater mode Frequency F
_The PLL synthesizer unit 10 is controlled to set to ₂ (step S9). Therefore, a standby operation state is established in the control channel in the repeater mode, and the process proceeds to step S3 to perform the above operation. If F _M = 1, is set to 0 the mode change flag F _M returns to step S1.
By this operation, the scan mode in which the standby operation state in the direct mode communication channel and the standby operation state in the repeater mode control channel are alternately repeated at 250 msec intervals until a radio wave having an electric field strength equal to or higher than a predetermined level can be received. become.

The field strength of the received signal at step S3 is if the predetermined level or more, the mode switching flag F _M it is determined whether or not 0 (step S11). In the case of F _M = 0, which received the radio wave having a predetermined level or higher field strength in the communication channel of the direct mode, the received signal is superimposed tone signal and it is judged whether or not detected above 50msec (Step S12). Since a tone signal is superimposed during transmission, the tone signal is detected. If a tone detection signal is supplied from the signal detection circuit 30 and it has continued for 50 msec or more,
The process proceeds to a call operation in step S13. However,
If the tone detection signal is not supplied from the signal detection circuit 30 and the tone detection signal is supplied but does not continue for 50 msec or more, the process proceeds to step S8, and the standby operation is performed again.

In the call operation in step S13, the antenna switch 2 is set to the selected state on the transmitting unit 4 side by the ON operation of the pre-talk switch, and the transmitting unit 4 is activated to be in the transmitting state by turning on the pre-talk switch. The operation causes the antenna switch 2 to be in the selected state on the receiving unit 3 side, and the receiving unit 3 is activated and the device returns to the receiving state. As a result, it is possible to talk with the partner station.

When the call operation is started, the controller 1
9 is operated (step S).
14), it is determined whether or not the press talk switch is on (step S15). When the press talk switch is turned off, it is determined whether or not the call timer has finished counting (step S16). When the press-talk switch is turned on, the tone signal generator 28 is instructed to generate a tone signal of a predetermined frequency (step S17), and then step S16 is executed. If it is determined in step S16 that the call timer is counting, the process proceeds to step S15 to continue the call operation, and if it is determined that the call timer has finished counting, the process returns to step S2 to perform the standby operation. .

If it is determined in step S11 that F _M = 1, since a radio wave having an electric field strength equal to or higher than a predetermined level is received on the control channel in the repeater mode, the operation is in the repeater mode. In the repeater mode, the control channel is captured (step S1).
8) It is determined whether or not the capturing operation has been properly performed (step S19). In the capturing operation, the bit synchronization signal and the frame synchronization signal in the control signal transmitted from the base station on the control channel are received, the bit synchronization and the frame synchronization are performed, and the supervisory code and the system code are stored in the internal memory in advance. This is an operation of continuously detecting two or more frames that coincide with each other. If the capturing operation is not performed properly, the process returns to step S1 and waits for the radio channel having the electric field strength of the predetermined level or more at the 250 msec interval in the standby mode in the direct mode communication channel and the control channel in the repeater mode. Is alternately repeated.

In step S19, if the capturing operation is properly performed, a standby operation is performed (step S2).
0). In this standby operation, when an error is continuously detected in the received frame synchronization signal for 10 consecutive frames, or when a mismatch between the received supervisory code and the system code and the code previously stored in the internal memory continues. 5
If the frame continues (step S21), the standby operation is canceled and the process returns to step S1. If the control signal received in the standby operation does not satisfy the condition for releasing the standby operation in step S21, the operation in the repeater mode as in the related art continues. For details of the operation in the repeater mode, refer to “800M
Hz (Broadband) MCA Radio Equipment Standards for Radio Stations that Perform Land Mobile Communications ”(Radio System Development Center issued in August 1990) has been formulated as a control procedure for radio stations other than the MCA control station. The description here is omitted.

[0022]

As described above, in the MCA type radio telephone apparatus of the present invention, the reception state on the control channel in the repeater mode and the reception state on the communication channel in the direct mode are alternately repeated at predetermined intervals, and The operation in the repeater mode is started when a signal is received on the control channel in the mode, and the operation in the direct mode is started when a signal is received on the communication channel in the direct mode. Therefore, as shown in FIG. 5, when both mobile stations A and B making a call are located in the same service area S, a call can be made in the repeater mode via the base station C. As shown in FIG. 6, when one or both of the mobile stations A and B are located outside the service area S provided by the base station C, one of the mobile stations A and B is one of the mobile stations A and B. If the station performs a call operation in the direct mode, the radio wave generated by the call operation is received by the other station, so that the operation can be automatically performed without the user operating the other station to switch the operation mode to the direct mode. Then, a call can be made on the direct mode call channel. Also, as shown in FIG.
Is located in the same service area S, the radio wave is interrupted by one of the mobile stations A and B and the base station C by an obstacle D such as a building, and a call is made in the repeater mode. If it is not possible, in this case as well, if one of the mobile stations A and B performs a call operation in the direct mode, the user of the other station operates the automatic operation mode without switching the operation mode to the direct mode. It becomes possible to talk in direct mode. Furthermore, according to the present invention, since it is confirmed that the reception state is good during scan control, the state is switched to the call state,
Good communication is possible in both the repeater mode and the direct mode.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing a configuration of a control signal.

FIG. 3 is a flowchart showing an operation of a controller in the apparatus of FIG. 1;

FIG. 4 is a flowchart showing a continuation of the operation in FIG. 3;

FIG. 5 is a diagram for explaining the movement positions of mobile stations A and B.

FIG. 6 is a diagram for explaining moving positions of mobile stations A and B.

FIG. 7 is a diagram for explaining the movement positions of mobile stations A and B.

[Description of Signs of Main Parts]

 DESCRIPTION OF SYMBOLS 1 Antenna 2 Antenna switch 3 Receiving part 4 Transmitting part 9, 23 VCO 10, 24 PLL synthesizer part 19 Controller

Claims (1)

(57) [Claims] 1. A repeater mode in which data communication with a base station on a control channel can be performed with a partner station via a base station on a communication channel designated by the base station among a plurality of communication channels. A multi-channel access type radio telephone device comprising, as a call operation mode, a direct mode in which a call can be directly made with a partner station on a call channel different from the call channel in the repeater mode, and a control channel in the repeater mode. A scan control means for performing a scan mode in which a reception state in the communication mode and a reception state in the direct mode communication channel are alternately repeated at predetermined intervals, and a signal on a control channel in a repeater mode by the scan control means.
And There repeater mode control means for starting the operation in the repeater mode when received, and direct mode control means for starting the operation in the direct mode when a signal is received at direct mode of communication channel by the scan control means ,
Have a, the scan control means above a predetermined level field
If a strong signal is received for a predetermined time or more
The repeater mode control means or the direct mode control
A wireless telephone device for activating a means .