JPH05252111A - Mobile radio communication equipment - Google Patents

Abstract

PURPOSE:To surely prevent a various kinds of trouble with respect to call issuing connection by precisely recognizing whether or not an area where its own equipment exists is a home area by a talker when a call is issued, and performing speech by always recognizing the system of a connection destination thereby. CONSTITUTION:This equipment is made up in such a way that system identification information SIDA sent from a base station via an access channel for outgoing call control is detected in a call issuing control procedure, and the information SIDA is compared with system identification information SIDp sent from the base station via a P-channel when initialization is performed and the system identification information SIDH of a system stored in an ID-ROM 33 in advance and to which its own equipment belongs, and the display of (ROAM) on an LCD display 37 is updated corresponding to a comparison result.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mobile radio communication device used in a mobile radio communication system such as a car radio telephone system or a mobile radio telephone system, and in particular, whether the device exists in its own service area. The present invention relates to a mobile wireless communication device having a function of displaying whether or not.

[0002]

2. Description of the Related Art As one of mobile radio communication systems, a car radio telephone system employing a cellular system is known. This type of system includes, for example, a control station CS connected to a wired telephone network NW as shown in FIG. 10, and a plurality of base stations BS1 to BSn connected to the control station CS via wired lines CL1 to CLn, respectively. And a plurality of mobile telephone devices MS1 to MSm as mobile stations. The base stations BS1 to BSn form radio zones E1 to En called cells in different areas. The mobile telephone devices MS1 to MSm are connected to a base station in a wireless zone in which the mobile telephone device is located via a wireless channel, and further connected to the wired telephone network NW from this base station via a control station CS. Then, in this state, it becomes possible to talk with the wired telephone connected to the wired telephone network NW. When the mobile phone devices MS1 to MSm move to another wireless zone during a call, the wireless channel is switched to the wireless channel of the base station of the moving destination under the control of the control station CS, and the call continues. That is, each of the mobile telephone devices MS1 to MSm can make a call with another telephone via the adjacent base station as long as it exists in the service area formed by the system to which the own station belongs.

By the way, in recent years, this type of automobile radiotelephone system has been constructed not only in the metropolitan area and other metropolitan areas but also in areas centering on local cities. That is, a plurality of systems having the same standard form service areas in different areas to provide wireless communication services. Under such circumstances, the car telephone device of each system cannot make a call in the service area of another system.
Or, even if you can make a call, the charge is generally high. Therefore, it is desirable for the subscriber to be able to know whether or not the local station exists in the service area formed by the system to which it belongs, that is, in the home area. It is considered to provide a display function.

An example of the operation of the car telephone device having the function of confirming and displaying the service area will be briefly described below. When the power of the device is turned on, the device first initializes the operating state of each circuit in the device, and then a control channel called a paging channel (hereinafter referred to as P channel) for receiving a control signal such as an incoming call signal. select. The P channel is selected by sequentially receiving a plurality of P channels, measuring the received electric field strength thereof, and detecting the one having the highest received electric field strength. When the P channel is selected, the P channel is set in the receiver to establish the word synchronization, and thereafter the standby operation state is set. In the standby state, the P channel is reset every 5 minutes.

At this time, the system information is detected from the control signal sent by the P channel, and the system identification information SIDp included in this system information is stored. Then, the received system identification information SIDp
Is compared with the identification information SIDH of the system to which its own station is stored in advance in the identification information memory (ID-ROM). Then, if the two pieces of identification information SIDp and SIDH match, it is determined that this device exists in the home area. On the other hand, if the two pieces of identification information SIDp and SIDH do not match, it is determined that this device exists in the service area of another system, and the LCD display indicates that the service area is out of the range, for example, "ROAM". Is displayed. Therefore, the speaker can confirm whether or not the own station is located within the service area of the system to which the speaker belongs by seeing this "ROAM" display.

[0006]

However, such a conventional car telephone system has the following problems to be solved. That is, the conventional device determines whether or not the device itself is present in the home area area based on the system identification information sent from the base station via the P channel set in the standby operation state. After that, the area display according to the determination result is held until the system identification information SIDp is acquired by the next resetting of the P channel. Therefore, even if the device itself moves from the home area to the service area (roam area) of another system in a short time, the contents of the area display are still the contents before the movement. That is, the display content of the device is that it is present in the home area.
Therefore, although the device is actually in the service area of another system, the speaker determines that the device is in the home area and makes a call as it is. As a result, I couldn't make a call, or I was charged an expensive fee without knowing it.

Contrary to the above case, when the own device is located in another service area at the time of acquiring the system identification information SIDp in the standby operation state and returns to the home area at the time of calling. However, the area display remains as it was before the move. In other words, in this case, the display content indicates that the own device is still in the service area of another system, although it is in the home area. Therefore, although the speaker is actually talking to the system within the home area, the speaker displays that the device is outside the home area, which is extremely inappropriate.

The present invention has been made in view of the above circumstances, and an object of the present invention is to enable a speaker to accurately grasp whether or not the area in which the device is present is a home area when making a call. Accordingly, it is an object of the present invention to provide a mobile radio communication device capable of surely preventing a variety of troubles related to call connection by making a call while knowing the connection destination system without fail.

[0009]

In order to achieve the above object, the present invention provides a mobile radio communication device selectively used in a plurality of different service areas respectively formed by a plurality of mobile radio communication systems of the same type. In the above, there is provided an area display means for displaying information for indicating whether or not the own device exists in the service area of the system to which the own device belongs, and a display control means. Then, the display control means detects the first system identification information sent from the base station via the predetermined control channel set during the call control procedure, and detects the detected first system identification information. The display contents of the area display means are updated in comparison with the second system identification information of the system to which the self belongs, which is stored in advance.

According to another aspect of the present invention, in addition to an area display means for displaying information for indicating whether or not the own device exists in the service area of the system to which the own device belongs, a first display is provided. The control means and the second display control means are provided. Then, the first display control means detects and stores the first system identification information transmitted from the base station via the predetermined control channel set in the standby state, and the detected first system identification information is stored. The system identification information is compared with the second system identification information of the system to which the user belongs, which is stored in advance, and the comparison result is displayed on the area display means, and the second display control means Detecting third system identification information sent from the base station via a predetermined control channel set during the call control procedure, and using the detected third system identification information as the second system identification information. By comparing, the display contents of the area display means are updated according to the comparison result.

[0011]

As a result, according to the present invention, at the time of call control, the position of the own device is re-determined based on the third system identification information coming from the base station during this control procedure, and according to the result The display contents of the area display means are updated. For this reason, when a call is made, even if the device itself moves from the home area to the service area of another system, or from the service area of another system to the home area, it is always Area information corresponding to the current position of the device is displayed. Therefore, the speaker can accurately determine whether or not the own device is present in the home area from the updated latest display content. Therefore, like the conventional device, even though the device is actually in the service area of another system, it is determined that the device is in the home area, and the speaker directly makes a call. As a result, problems such as not being able to make a call and being charged an expensive fee without knowing it are reduced. Further, it is possible to prevent a problem that the caller gives up calling without knowing this even though the own device is actually located in the home area.

[0012]

EXAMPLES The present invention will be described below based on examples. FIG. 1 is a circuit block diagram showing a configuration of a car telephone system according to an embodiment of the present invention. This car telephone device is roughly classified into a transmission system, a reception system and a control system. A power supply circuit 40 generates an operating voltage Vcc necessary for the device based on the output of the battery 41.

The transmission system is a microphone 1 as a transmitter.
1, a speech coder (SPCOD) 12, an error correction coder (CHCOD) 13, and a digital modulator (MOD)
14, a multiplier 15, a power amplifier (PA) 16, a high frequency switch circuit (SW) 17, and an antenna 18. The voice encoder 12 encodes the transmission signal output from the microphone 11. The error correction encoder 13 performs error correction encoding on the digitized transmission signal output from the speech encoder 12 and the digitized control signal output from the control circuit 30 described later. The digital modulator 14 generates a modulation signal according to the digitized transmission signal output from the error correction encoder 13. In the multiplier 15, this modulated signal is mixed with the local oscillation signal output from the frequency synthesizer 31, and thereby frequency-converted into a radio frequency signal. In the power amplifier 16, the multiplier 1
The wireless transmission signal output from 5 is amplified to a predetermined transmission power. The high frequency switch 17 becomes conductive only during the transmission time slot designated by the control circuit 30,
During this period, the wireless transmission signal output from the power amplifier 16 is supplied to the antenna 18 and transmitted from the antenna 18 to a base station (not shown).

On the other hand, the receiving system is a receiver (RX) 21.
, Digital demodulator (DEM) 22, error correction decoder (CHDEC) 23, and speech decoder (SPDEC) 2
4 and a speaker 25 as a receiver.

The receiver 21 performs a mixing operation for directly frequency-converting the received high frequency signal received by the antenna 18 and the high frequency switch 17 into an intermediate frequency signal or a baseband signal. The digital demodulator 22 performs bit synchronization and frame synchronization, that is, word synchronization with respect to the received digital signal output from the receiver 21, and also performs digital demodulation. Then, the synchronization signal obtained by the word synchronization is supplied to the control circuit 30. The error correction decoder 23 performs error correction decoding on the digital demodulated signal output from the digital demodulator 22.
The signal obtained by this error correction decoding consists of a digital received signal and digital control information, of which the digital received signal is input to the voice decoder 24, and the digital control information is used for various control such as channel setting and call. Therefore, it is taken into the control circuit 30. The voice decoder 24 performs a decoding process for the digital call signal. Then, the analog reception signal restored to the original state by this decoding process is output as loudspeaker from the speaker 25.

On the other hand, the control system is a control circuit (CONT) 30.
, A frequency synthesizer (SYN) 31, a system identification information memory (ID-ROM) 33, a control data memory (RAM) 34, and a console unit (CU) 35.
And a display drive circuit 36 and a liquid crystal display (LCD) 37. The frequency synthesizer 31 generates a local oscillation signal corresponding to each channel frequency for control, speech and synchronization designated by the control circuit 30. ID-
The system identification information SIDH of the system to which the device itself belongs is stored in the ROM 33 in advance. RAM34 is
It is used to store control information such as a telephone number input by a dial key and system identification information sent from a base station via various control channels as necessary. The console unit 35 is provided with keypads such as dial keys and call request keys. The LCD display 37 is driven by the display drive circuit 36, and displays information indicating whether or not the own device exists in the service area of the system to which the own device belongs, that is, the home area, together with the dial number and the like. Used for.

By the way, the control circuit 30 is provided with, for example, a microcomputer as a main control section, and has a first area in addition to a normal control function such as initial setting of the apparatus, a series of control relating to incoming / outgoing calls and a telephone call. Display control means 30
a and second area display control means 30b.

The first area display control means 30a detects the system identification information SIDp sent from the base station via the P channel set in the standby state, and the RAM 3 is detected.
4 and compares the detected system identification information SIDp with the system identification information SIDH of the system to which the own device belongs, which is stored in advance in the ID-ROM 33. When SIDp and SIDH do not match, the device determines that the device exists in the service area of another system and causes the LCD display 37 to display, for example, "ROAM". Also, SIDp and SIDH
If the two match, the device determines that the device is present in the home area and does not display the "ROAM" on the LCD display 37.

The second area display control means 30b receives the system identification information SI sent from the base station via the access channel (A channel) set during the call control procedure.
DA is detected, and the detected system identification information SID
Compare A with system identification information SIDH. And S
When the IDA does not match the SIDH, it is determined that the own device exists in the service area of another system, and “ROAM” is displayed on the LCD display 37.
On the other hand, if the SIDA matches SIDH, it is determined that the device is in the home area, and the LCD
The display of "ROAM" on the display 37 is erased.
Next, the operation of the device configured as above is controlled by the control circuit 3
It will be described according to the control procedure of 0. FIG. 2 is a flowchart showing the main routine.

When a power switch (not shown) is turned on,
The control circuit 30 first executes the reset operation in step 2a. That is, as shown in FIG.
The state of each part of the circuit is reset by a, then step 3
The setting of the locked state is monitored by b. The locked state is intended to prevent unauthorized use of the device by a third party.When the locked state is set, the device enters the locked state and is used unless a specific key operation is performed thereafter. It will be impossible. It should be noted that when the lock state is set, the LCD display 37 displays "LOCK".
Is displayed (step 3c). On the other hand, if the locked state is not set, the LCD display 37 displays "NOSVC" in step 3d.

When the reset is completed in this way, the control circuit 30 then executes the initialization operation in step 2b. That is, as shown in FIG. 4, first, step 4a is performed.
Scan a plurality of control channels (D channels) for initialization, and thereby select the channel having the highest received electric field strength and the channel having the next highest received electric field strength.
Then, in step 4b, control for establishing bit synchronization and frame synchronization, that is, word synchronization for the D channel having the highest received electric field strength is performed.
When word synchronization is established within a certain time by this control, the process proceeds to step 4c, where the system identification information SIDd is detected from the control information sent from the base station via the D channel, and step It is stored in the RAM 34 at 4e. Note that the above steps 4b and 4c
If the word synchronization cannot be established within a fixed time or the system identification information cannot be detected, the process proceeds to step 4d, and the D channel having the next largest received electric field strength is selected. The above steps 4b to 4e are controlled for the D channel.

When the initialization is completed in this way, the control circuit 30 then proceeds to step 2c and executes the control control of the control channel (P channel) for the standby operation. That is, as shown in FIG. 5, first, in step 5a, a plurality of P channels are scanned, and thereby, the channel having the largest received electric field strength and the channel having the next largest are selected. Next, in step 5b, control for establishing bit synchronization and frame synchronization, that is, word synchronization is executed for the P channel having the maximum received electric field strength. When the word synchronization is established within a certain time, the process proceeds to step 5c, where the system identification information SIDp is detected from the control information sent from the base station via the P channel, and this SIDp is detected. RAM3
Store in 4. In step 5b and step 5c, if the word synchronization is not established within a fixed time, or if the system identification information is not detected within the fixed time, the received electric field strength is changed to the next in step 5d. A large P channel is selected, and word synchronization is established and system identification information is detected for this P channel. If the system identification information SIDp detected from the P channel does not match the system identification information SIDd detected from the D channel at the time of initialization in step 5c, the process directly returns to the initialization control (step 2b).

By the way, the control circuit 30 executes the above step 5
When the system identification information SIDp is detected in c, the process proceeds to step 5e, where the first area display control is executed as follows. FIG. 6 shows the control procedure and control contents. That is, first in step 6a, the control circuit 30 compares the system identification information SIDp detected from the P channel with the system identification information SIDH of the system to which the own device belongs, which is stored in advance in the ID-ROM 33. Then, both identification information SIDp and S
If the IDH and IDH match, the device determines that the device exists in the home area and does not display "ROAM". On the other hand, when SIDp and SIDH do not match, it is determined that the own device exists within the service area of another system, and the process proceeds to step 6c, where the LCD display 37 is displayed. Display "ROAM".
Therefore, the user can know whether the current position of the own device is within the home area or within the service area of another system by the presence or absence of this "ROAM" display. Then, when the area is identified and displayed, the control circuit 30 thereafter shifts to the standby operation state (step 2d).

Now, assume that an incoming call signal arrives from the base station via the P channel in the standby operation state. Then, the control circuit 30 proceeds to step 2e, where the incoming call response control is executed. That is, the control circuit 30 first scans a plurality of control channels (A channels) called access channels used to establish a speech channel, and selects a channel having the highest received electric field strength and a channel having the next highest intensity. Then, after the word synchronization for the selected A channel is established, the incoming call response signal is returned to the base station via this A channel. After returning the incoming call response signal, the base station waits for the arrival of the call channel designating signal. When the call channel designating signal is received, a shorted burst is transmitted to set the time alignment. , Captures and sets a speech channel (SP channel) designated by the speech channel designation signal. Then, in this state, the system waits for reception of a calling signal (step 2f). When the ringing signal is received in this state, for example, a ringer sound is generated from a sounder (not shown), and thereafter the control circuit 30 enters a waiting state for the user's response (step 2g). And
When the user who recognizes the occurrence of the incoming call by the ringer sound operates the off-hook and responds, the control circuit 30 causes the step 2
After shifting to h, call control is executed.

Incidentally, the above-mentioned step 2f and step 2
When the call end operation is performed in step g, the control circuit 30 shifts to step 2i to release the reception state by the communication channel, and stops the operation of the transmission system in step 2j, and then the initialization operation. Return to. Further, in the states of steps 2f, 2g, and 2h, when the received electric field strength continuously drops below a predetermined level for a predetermined time or longer due to the influence of fading or the like, the control circuit 30 shifts to step 2j, where the transmission system After the operation of is stopped, it returns to the initialization operation.

On the other hand, the standby operation state (step 2d)
In, it is assumed that the call request key is operated or a call request is generated by voice dialing. Then, the control circuit 30 proceeds to step 2k and executes call control here as follows. FIG. 7 is a flowchart showing the control procedure and control contents, and FIG. 9 is a diagram showing a connection sequence between the base station and the mobile telephone device during the call control procedure.

That is, the control circuit 30 first executes step 7
At a, a timer for measuring the call acceptance time is started. This call acceptance time is set to 12 seconds, for example. The control circuit 30 then scans the plurality of A channels in step 7b, thereby selecting the channel having the largest received electric field strength and the channel having the next largest received electric field strength. Then, in step 7c, it is determined whether or not there is a calling intention, and if there is a calling intention, the process proceeds to step 7d, where control for establishing word synchronization for the A channel is performed. The determination as to whether or not there is a calling intention is made based on whether the calling flag is "1" or "0".
The calling flag is set to "1" when the "SEND" key is pressed after the telephone number of the other party is input. If it is determined that there is no calling intention, the process returns to the initialization operation.

When the word synchronization is established in step 7d, the control circuit 30 confirms the calling intention again in step 7f, and if there is the intention, the outgoing control channel (A channel) is captured and set in step 7g. To do. At this time, the system identification information SIDA is detected from the control information sent from the base station via the captured transmission control channel. Then, using the above-mentioned captured transmission control channel, a calling signal including information corresponding to the telephone number of the other party inputted by the user is sent to the base station (step 7).
h). If the transmission control channel cannot be acquired within the fixed time, it is determined that the acquisition has failed in step 7i, and the process returns to step 7f.

When the transmission of the calling signal is completed, the control circuit 30 proceeds to step 7j and executes the second area display control here. That is, as shown in FIG. 8, first, in step 8a, the control circuit 30
Compares the system identification information SIDA detected from the transmission control channel with the system identification information SIDH of the system to which the own device belongs stored in advance in the ID-ROM 33. If SIDA and SIDH do not match, the LCD display 37 displays "RO" in step 8c.
AM ”is displayed. On the other hand, when SIDA and SIDH match, the process proceeds to step 8c and the LCD is displayed here.
The "ROAM" being displayed on the display 37 is erased.

When the area display control is completed in this way, the control circuit 30 proceeds to step 7k to monitor the return of the calling response signal. Then, when the call response signal is returned from the base station, the control circuit 30 outputs the A signal as shown in FIG.
After the channel slot synchronization is established, a shorted burst is transmitted to set the time alignment, and then the process proceeds to step 7l. Then, in this step 71, control is performed to capture the speech channel (SP channel) designated by the call response signal, and if the acquisition of this SP channel is successful, then the state shifts to the speech state (step 2h). To do. Note that the above step 7
In k and step 71, if the return of the call response signal is not detected within a fixed time or if acquisition of the SP channel fails, the initialization operation is restored.

As described above, in the apparatus of this embodiment, the system identification information SIDA sent from the base station via the access control access channel is detected in the call control procedure, and this SIDA is detected by the ID-ROM 33. System identification information SI of the system to which the own device belongs stored in advance
The LCD display 37 is compared with DH and the comparison result is used.
The display of "ROAM" in is updated. Therefore, during the standby operation, the device moves from one area to another area, and as a result, the contents of the area information being displayed on the LCD display 37 (ON / OFF of “ROAM”)
Even if the content does not correspond to the area where the own device is actually located, the content of the area information being displayed on the LCD display 37 is corrected to the content corresponding to the actual position of the own device during call control. .. Therefore, it becomes possible for the user to accurately grasp whether the own device exists in the home area or the area of another system at the time of making a call, so that the system of the connection destination must be surely identified. You can make calls after knowing it. For this reason, it is possible to reliably prevent a problem that a call cannot be made or a high fee is charged without knowing.

The present invention is not limited to the above embodiment. For example, in the above embodiment, when the own device exists in the area of another system, that effect is indicated by "ROA
Although "M" is displayed and nothing is displayed when the device is present in the home area, "Home" is displayed when the own device is present in the home area, and the area of another system is displayed. When it is present, it may be configured such that it is not displayed, and "ROAM" and "HOME" may be respectively displayed according to the area where the own device is present. The display form in the case of "" may be made different from the case of the home area by, for example, blinking, different display colors, and simultaneously generating an alarm sound.

In the above embodiment, the car telephone device has been described as an example, but the present invention is applied to a mobile radio telephone device, a cordless telephone, and a mobile terminal device used in another mobile radio communication system such as an MCA system. Good.

In addition, the configuration of the apparatus, the control procedure and control contents of the control circuit, the type and configuration of the display means, the display form, etc. can be variously modified and implemented without departing from the scope of the present invention.

[0035]

As described in detail above, the present invention provides area display means for displaying information indicating whether or not the own device exists in the service area of the system to which the own device belongs, and a display. Control means, and the display control means detects the first system identification information sent from the base station via the predetermined control channel set during the call control procedure, and detects the detected first system identification information. The system identification information is compared with the second system identification information of the system to which it belongs, which is stored in advance, and the display content of the area display means is updated according to the comparison result.

According to another aspect of the present invention, in addition to the area display means for displaying information for indicating whether or not the own device exists in the service area of the system to which the own device belongs, a first display is provided. The control means and the second display control means are provided, and the first display control means detects the first system identification information sent from the base station via the predetermined control channel set in the standby state. The detected first system identification information is compared with the previously stored second system identification information of the system to which the self belongs, and the comparison result is displayed on the area display means. And the second display control means detects the third system identification information sent from the base station through the predetermined control channel set during the call control procedure, and the detected third system identification information is detected. The third system identification information as compared with the second system identification information is obtained so as to update the display of the area display means according to the comparison result.

Therefore, according to these inventions, the speaker can accurately know whether or not the area in which the device is present is the home area when making a call, so that the user can make a call while always knowing the connected system. In this way, it is possible to provide a mobile radio communication device capable of reliably preventing various troubles related to call connection.

[Brief description of drawings]

FIG. 1 is a circuit block diagram showing a configuration of a car telephone system according to an embodiment of the present invention.

FIG. 2 is a flowchart showing a main routine in a control circuit of the device shown in FIG.

3 is a flowchart showing a reset operation procedure and its contents in the flowchart shown in FIG.

FIG. 4 is a flowchart showing the procedure and contents of the initialization operation in the flowchart shown in FIG.

5 is a flowchart showing a control procedure and its contents relating to a P channel selection operation in the flowchart shown in FIG.

6 is a flowchart showing a procedure and contents of a first area display control in the flowchart shown in FIG.

FIG. 7 is a flowchart showing the generation control procedure and its contents in the flowchart shown in FIG.

8 is a flowchart showing the procedure and contents of the second area display control in the flowchart shown in FIG.

FIG. 9 is a diagram showing a connection sequence between a base station and a car telephone device during a call control procedure.

FIG. 10 is a schematic configuration diagram of a cellular phone system adopting a cellular system.

[Explanation of symbols]

NW ... Wired telephone network, CS ... Control station, CL, CL1-CL
n ... Wired line, BS1, BS2, ... Base station, MS1, M
S2, ... Mobile station, E1, E2, ... Wireless zone, 11 ... Microphone, 12 ... Speech coder (SPCOD), 13 ...
Error correction encoder (CHCOD), 14 ... Digital modulator (MOD), 15 ... Multiplier, 16 ... Transmission power amplifier (PA), 17 ... High frequency switch (SW), 18 ... Antenna, 21 ... Receiver (RX) , 22 ... Digital demodulator (DEMOD), 23 ... Error correction decoder (CHDE)
C), 24 ... Speech decoder (SPDEC), 25 ... Speaker, 30 ... Control circuit (CONT), 31 ... Frequency synthesizer (SYN), 33 ... System identification information memory (I
D-ROM), 34 ... Control data memory (RAM), 3
5 ... Console unit (CU), 36 ... Display drive circuit, 37 ... LCD display device, 40 ... Power supply circuit, 41 ... Battery, 30a ... First area display control means, 30b ... Second area display control means.

Claims (2)

[Claims] 1. A mobile radio communication device selectively used in a plurality of service areas formed in different areas by a plurality of mobile radio communication systems, wherein the own device exists in the service area of the system to which the mobile radio communication device belongs. Area display means for displaying information for indicating whether or not the first system identification information sent from the base station via a predetermined control channel set during the call control procedure is detected, Display control for comparing the detected first system identification information with the second system identification information of the system to which the self belongs, which is stored in advance, and updating the display content of the area display means according to the comparison result. A mobile radio communication device comprising: 2. A mobile radio communication device selectively used in a plurality of service areas formed in different areas by a plurality of mobile radio communication systems, wherein the own device exists in the service area of the system to which the mobile radio communication device belongs. Area display means for displaying information for indicating whether or not the first system identification information is sent from the base station via a predetermined control channel set in the standby state and stored. At the same time, the detected first system identification information is compared with the second system identification information of the system to which the self belongs, which is stored in advance, and the first result is displayed on the area display means. Detecting the third system identification information sent from the base station via the display control means and the predetermined control channel set during the call control procedure, The detected third system identification information is used as the second
And a second display control means for updating the display content of the area display means in accordance with the comparison result of the system identification information.