JP2001045556A - Radio communication system, and communication controller and mobile unit used for the system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To allow a user to efficiently utilize communication in an extension communication mode and an inter-slave-unit communication mode by using 1st and 2nd mobile units that receive a control signal from a communication controller through a control channel and make radio communication in a 2nd communication mode according to an instruction of the control signal. SOLUTION: Mobile units A, B in the standby state receive a control channel from a communication controller 50 for a prescribed period. When the mobile unit A calls the mobile unit B, the call is sent to the communication controller 50 through the control channel. When the communication controller 50 confirms a control message permitting communication in an inter-slave-unit communication mode, the communication controller 50 transmits an instruction of switching to the inter-slave-unit communication mode to the destination mobile unit B through the control channel. A controller 31 of the mobile unit B receiving the switching instruction to the inter-slave-unit communication mode changes the communication mode into the inter-slave-unit communication mode. Then the mobile units A, B receiving the control signal through the control channel from the communication controller 50 make radio communication in a 2nd mode.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radio communication system in which radio communication of a plurality of mobile units is controlled by a communication control unit. More specifically, each mobile unit relays the communication control unit. The present invention relates to a wireless communication system that enables communication in a first communication mode for performing communication and a second communication mode for directly performing wireless information communication between mobile devices.

[0002] The present invention also relates to a communication control device and a mobile device used in such a wireless communication system.

[0003]

2. Description of the Related Art Conventionally, a base station (
Main unit) and multiple mobile units (PHS terminal, cordless handset)
PHS (Personal Handy Phone
The base station (master unit) relays wireless communication between mobile units as a so-called extension communication mode, and the so-called slave unit communication mode performs direct wireless communication between mobile units. And Further, each mobile device can independently perform so-called public communication via a base station connected to a public line network.

[0004] In the extension communication mode in the PHS, each mobile station is on standby on a control channel from the base station. When a certain mobile station transmits a call to another mobile station on a control channel, the base station that has received the call further transmits a call to another partner mobile station on the control channel. When a response to the call is returned from the other mobile station on the control channel, the base station establishes a call between the mobile stations, and communication between the mobile stations is performed by relaying the base station.

[0005] In the inter-slave communication mode, each mobile station is in a standby state for receiving a predetermined standby channel. In this state, after one mobile station transmits a call, and the other mobile station receiving the call responds to the call,
Direct wireless communication is performed between mobile devices using a predetermined wireless channel.

[0006]

In a conventional wireless communication system such as the PHS described above, when a communication mode between slave units is performed, a call is randomly generated in each mobile unit.
Each mobile station needs to receive a standby channel determined by each other, and always or frequently check the presence or absence of a call to its own station. For this reason, the power consumption of each mobile device is so large that the standby time and the talk time are reduced.

When realizing simultaneous standby in the extension communication mode and the inter-slave communication mode, each mobile station includes a control channel from a base station (master) and a standby channel used in inter-slave communication. Must be received alternately. For this reason, each mobile station cannot receive the call even if it receives a call in the inter-child-station communication mode from another mobile station while receiving the control channel from the base station, for example. , Connection quality is degraded.

[0008] Further, in the extension communication mode, the base station relays all communications between a plurality of mobile stations in a standby state after receiving a control channel from the base station (master station). Since the number of calls that can be accommodated by the communication control device of the base station is finite, if the communication traffic in the extension communication mode increases, a connection may not be established, and the connection quality deteriorates.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and a first problem thereof is that a wireless communication which enables efficient use of communication in a so-called extension communication mode and in a so-called communication mode between slave units is provided. A communication system is provided. A second object is to provide a communication control device used in such a wireless communication system.

[0010] A third object is to provide a mobile station used in such a wireless communication system.

[0011]

In order to solve the above-mentioned first problem, the present invention provides a communication control device and a standby state on a control channel from the communication control device. A plurality of mobile devices, each mobile device performs a wireless communication via a communication control device when a call is received on a control channel, and a direct wireless communication between mobile communication devices. In a wireless communication system capable of performing a second communication mode, the communication control device, when receiving a call from the first mobile device to the second mobile device on the control channel, the first and second communication modes Communication mode switching instructing means for transmitting a control signal for instructing switching to the second communication mode on the control channel to the second mobile station, and receiving the control signal on the control channel from the communication control device. First The second mobile terminal, configured by the second communication mode in accordance with the instructions to perform wireless communication.

[0012] In such a wireless communication system, each mobile station can perform either of a first communication mode in which wireless communication is performed by relaying a communication control device or a second communication mode in which mobile stations directly perform wireless communication. Even in the case of performing wireless communication in the communication mode, a standby state is established on a control channel from the communication control device. Therefore, a call for performing wireless communication using any communication mode can be reliably received. Further, it is no longer necessary to constantly or frequently check a call in the second communication mode in which the mobile units directly perform wireless communication directly with each other.

[0013] Further, when the communication control device receives a call from the first mobile station to the second mobile station on the control channel, the second mobile station receives the call from the first mobile station and the second mobile station. Is switched to the first communication mode, and wireless communication in the second communication mode is performed between the first mobile device and the second mobile device. As a result, communication traffic in the first communication mode in which wireless communication between mobile devices is performed via the communication control device is reduced, and connection quality of wireless communication via the communication control device is improved.

In the above wireless communication system, the communication control device can be installed in a so-called base station, a relay station or a station functioning as a master unit. Also, each mobile device
It can include a PHS terminal, a portable information terminal having a communication function, and the like. From the viewpoint of starting communication in the second communication mode in accordance with an instruction from the communication control device, the present invention provides a wireless communication system in which the communication control device switches communication modes in the wireless communication system. The control signal transmitted from the instruction means to the first mobile device includes an instruction to switch to the second communication mode, and an instruction to recall the second mobile device in the second communication mode, According to the recall instruction, one mobile device can be configured to recall the second mobile device in the second communication mode.

In view of the fact that the communication control device can designate a wireless channel used for communication in the second communication mode, the present invention provides a wireless communication system in each of the above wireless communication systems. The control signal transmitted from the communication mode switching instructing means of the control device to the first and second mobile stations includes a radio channel used for communication in the second communication mode together with an instruction to switch to the second communication mode. And the first and second mobile devices can be configured to perform wireless communication in the second communication mode using the specified wireless channel.

In view of the fact that it is possible to switch to the second communication mode based on information from the mobile station, the present invention provides a communication mode switching instruction of the communication control device as described in claim 4. The means, when the call from the first mobile station to the second mobile station includes a message permitting communication in the second communication mode, the second Can be configured to transmit a control signal instructing switching to the communication mode.

In order to solve the second problem, the present invention provides a communication control apparatus and a plurality of mobile stations which are on standby on a control channel from the communication control apparatus. Each mobile device has a first communication mode for performing wireless communication via a communication control device when receiving a call on a control channel, and a second communication for performing direct wireless communication between mobile communication devices. In the communication control device used in the wireless communication system capable of mode, when a call to the second mobile device from the first mobile device is received on the control channel, the first and second mobile devices Communication mode switching instructing means for transmitting a control signal for instructing switching to the second communication mode on the control channel,
With this control signal, the first and second mobile devices are switched to the second communication mode to perform wireless communication.

Furthermore, in order to solve the above third problem, the present invention provides a communication control apparatus and a plurality of communication control apparatuses which are in a standby state on a control channel from the communication control apparatus. Each mobile device has a first communication mode of performing wireless communication via a communication control device when receiving a call on a control channel, and a second communication mode of performing direct wireless communication between mobile devices. In the mobile device used in the wireless communication system capable of the communication mode, when receiving a control signal instructing the switch to the second communication mode from the communication control device on the control channel, the communication mode is changed to the second Communication mode switching means for switching to a communication mode, wherein when a control signal from the communication control device is received after transmitting a call to another mobile device through a control channel from the communication control device, the communication mode Configured in a second communication mode which is switched by de switching means so as to initiate communication with the other mobile device.

From the viewpoint that the function of receiving a call in the second communication mode can be realized, the present invention is directed to claim 10
As described in the above, when the mobile device receives the control signal from the communication control device without transmitting a call to another mobile device, the second communication mode switching means In the communication mode, it can be configured to be in a standby state on a predetermined standby channel.

From the viewpoint of enabling wireless communication between mobile stations even when the positional relationship of the mobile stations is not suitable for wireless communication in the second communication mode, the present invention is directed to claim 14.
As described in the above, in each of the mobile devices, after the communication mode is switched to the second communication mode by the communication mode switching means, it is determined whether or not communication in the second communication mode is possible. The communication mode can be returned to the first communication mode when the determination means determines that communication in the second communication mode is not possible.

In such a mobile device, when wireless communication in the second communication mode for performing direct wireless communication between the mobile devices is not possible, the wireless communication in the first communication mode via the communication control device is not possible. Switch to communication. From the viewpoint that it is possible to easily determine that communication in the second communication mode is not possible in the mobile device that transmits the call, the present invention provides:
As described in claim 15, in the mobile device,
The determining means, after transmitting a call to another mobile device on a control channel from the communication control device, sets the communication mode to the second communication mode by the communication mode switching device based on the control signal from the communication control device. When switched,
A first timer that is activated on the basis of the call in the second communication mode, and a second communication mode when a time measured by the timer reaches a predetermined time before a response to the call is received. May be configured to determine that communication is not possible.

In view of the fact that it is possible to easily determine that the communication in the second communication mode is not possible at the mobile station on the side of receiving the call, the present invention provides the above-mentioned mobile station. In the communication device, when the communication mode is switched to the second communication mode by the communication mode switching device based on the control signal from the communication control device without transmitting a call to another mobile device, ,
A second timer that starts based on the switching of the communication mode, and is configured to determine that communication in the second communication mode is not possible when a time measured by the timer reaches a predetermined time. be able to.

[0023]

Embodiments of the present invention will be described below with reference to the drawings. A wireless communication system according to an embodiment of the present invention is configured, for example, as shown in FIG. This wireless communication system is a PHS (Personal Handy Phone System), and wireless communication (public communication) via a public line network and wireless communication within a predetermined area (office, home, etc.) (self-owned communication) Both have been realized.

In FIG. 1, a plurality of mobile units (slave units) 10, 11, and 12 and a communication control unit 50 for performing wireless communication control of these mobile units 10, 11, and 12 are provided in a private communication area 100. I have. Each mobile device 10, 11, 12
It is a PHS terminal (slave unit for voice) or an information processing device (computer) having a communication function of the PHS terminal and its peripheral device (such as a printer) (a slave unit for data).

In this example, the communication control device 50 is provided in a relay station. The communication control device 50 functions as a PHS terminal that performs wireless communication with a base station 150 connected to a public line network NW in public communication, and a plurality of mobile devices (child devices) 10 and 11 in private communication. 12 and also functions as a repeater for converting public communication into private communication.

In the above wireless communication system,
Focusing on the private communication, the configurations of the communication control device 50 and the mobile devices that communicate with each other (for example, the mobile devices 10 and 12, hereinafter referred to as mobile device A and mobile device B) are illustrated in FIG. As shown. 2, the communication control device 50 includes a transmitter 52, a receiver 53, and a control device 51 that controls the transmitter 52 and the receiver 53. Similarly, each mobile unit A (B) also controls
1 (31), the transmitter 22 (32) and the receiver 23 (3
3). Controllers 21 and 3 of mobile units A and B
Reference numeral 2 has a function of mode switching control between an extension communication mode and a communication mode between slave units, which will be described later, and an automatic recall function.

In the private communication, communication in the extension communication mode and communication in the slave unit mode are possible. In the extension communication mode, for example, a signal transmitted from the transmitter 22 of the mobile device A calling the mobile device B is transmitted to the receiver 5 of the communication control device 50.
3, and the received signal is transmitted from the transmitter 52 to the receiver 3 of the mobile unit B of the partner under the control of the control device 51.
3 is sent. That is, the wireless communication between the mobile device A and the mobile device B is performed by relaying the communication control device 50. In addition,
Also in the case of calling the mobile station A from the mobile station B, the communication between the mobile stations B and A is performed by relaying the communication control device 50 in the extension communication mode, as described above.

In the inter-substation mode, the signal transmitted from the transmitter 22 of the mobile station A that calls the mobile station B is transmitted directly to the mobile station B.
Of the mobile station B,
2 is also directly received by the receiver 23 of the mobile station A. Communication in the slave unit mode is performed by mobile unit A,
This is performed using a predetermined wireless channel between B and B. In the wireless communication system as described above, the private communication is, for example,
This is performed according to the procedure shown in FIG.

In FIG. 3, mobile units A and B are:
It is in a standby state on a control channel from the communication control device 50. In this standby state, the mobile devices A and B receive a control channel from the communication control device 50 at a predetermined cycle. In this state, when the mobile station A calls the mobile station B, the call is transmitted through the communication control device 50 via the control channel.
Sent to. The control signal related to this call includes a control message allowing communication in the communication mode between child devices. Upon receiving the call, the communication control device 50 confirms the control message that allows communication in the handset communication mode, and switches the call destination mobile device B to the handset communication mode on the control channel. Send instructions. The control signal instructing switching to the communication mode between child devices includes a control message specifying a wireless channel used for communication in the communication mode between child devices. The control device 31 of the mobile device B that has received the instruction to switch to the communication mode between child devices switches the communication mode to the communication mode between child devices. As a result, the mobile station B cancels the standby state on the control channel from the communication control device 50, and enters the standby state on the standby channel used in the inter-child-unit communication mode.

Further, the communication control device 50, which has received the call from the mobile unit A to the mobile unit B as described above, switches the mobile unit A to the inter-subunit communication mode by using the control channel, and An instruction to recall B is transmitted. The control signal for switching to the handset communication mode and for instructing the mobile station B to make a recall includes a control message that specifies a wireless channel used for communication in the handset communication mode.
The control device 21 of the mobile device A, which has received the instruction to switch to the communication mode between child devices and to re-call the mobile device B, switches the communication mode to the communication mode between child devices and sets the communication mode to the communication mode between child devices. The mobile station B makes a call again. That is, mobile unit A
Releases the standby state on the control channel from the communication control device 50, and makes a re-call of the mobile station B on the standby channel used in the communication mode between child apparatuses.

When mobile station B receives the call from mobile station A due to the re-calling, mobile station B returns a response signal to mobile station A. When mobile device A receives this response, mobile device A performs direct wireless communication with mobile device B using the specified wireless channel (communication between child devices). When the disconnection signal is transmitted from the mobile device A to the mobile device B while the communication between the mobile devices is being performed between the mobile device A and the mobile device B,
The mobile station B that has received the disconnection signal returns a release signal to the mobile station A. Then, the mobile device A having received the release signal further transmits a release completion signal to the mobile device B. Thus, the communication in the communication mode between the slave units is completed.

When the mobile station A transmits the release completion signal,
When the communication mode is switched to the extension communication mode, and mobile station B receives the release completion signal, mobile station B switches the communication mode to the extension communication mode. As a result, mobile device A and mobile device B
Again, the communication control device 50 enters a standby state on the control channel. On the other hand, if the mobile device A and the mobile device B exist in the private communication area 100 but there is an obstacle (a building, a wall, etc.) between the mobile device A and the mobile device B and communication between the mobile devices cannot be performed, The communication between the mobile device A and the mobile device B
It is performed according to the procedure shown in 4.

In FIG. 4, similarly to the above-described example, the mobile units A and B enter a standby state on the control channel from the communication control device 50. In this state, for example, the mobile unit A Is transmitted on the control channel. Then, the communication control device 50 that has received this call confirms the control message allowing communication in the inter-slave device communication mode in the same manner as in the above-described example, and instructs the mobile device B to switch to the inter-slave device communication mode. Perform the switching instruction and
The switching instruction to the mobile device A is switched to the communication mode between the mobile devices, the wireless channel to be used in the communication mode between the mobile devices is specified, and the recalling instruction to the mobile device B is performed. The control device 31 of the mobile device B, which has received the instruction to switch to the communication mode between child devices from the communication control device 50 as described above, starts the internal timer together with the switching of the communication mode to the communication mode between child devices. On the other hand, the control device of the mobile device A that has received the instruction to switch to the communication mode between the mobile devices from the communication control device 50, the designation of the radio channel to be used in the communication mode between the mobile devices, and the instruction to recall the mobile device B Reference numeral 21 starts the internal timer together with switching of the communication mode to the communication mode between the slave units and control of re-calling of the mobile station B.

Here, when the mobile station A and the mobile station B are in a positional relationship in which direct communication cannot be performed due to an obstacle, the call transmitted from the mobile station A using the standby channel is not received by the mobile station B. After switching to the communication mode between child devices, the control device 31 of the mobile device B changes the communication mode to the extension when the internal timer reaches a predetermined value without receiving a call from another mobile device (timer expires). Switch to communication mode. In the same situation, the control device 21 of the mobile device A
If the internal timer reaches a predetermined value (timer expires) without returning a response signal from mobile station B after re-calling to mobile station B in the inter-substation communication mode, the communication mode is switched to the extension communication mode.

When the communication mode of each of the mobile stations A and B is switched to the extension communication mode in this way, each of the mobile stations A and B again enters the standby state on the control channel from the communication control device 50. Become. Then, the mobile device A transmits a call for the mobile device B to the communication control device 50 on this control channel (recall). Control signals related to this call include:
A control message indicating that communication in the communication mode between child devices is not permitted (not permitted) is included. From this mobile station A to mobile station B
When the communication control device 50 that has received the call to the mobile terminal confirms the control message indicating that communication in the communication mode between child devices is not permitted, the communication control device 50 returns a call acceptance to the mobile device A and makes a call to the mobile device B. Send the call. Mobile station B responds to this call
When the communication control device 50 receives the response from
Communication in the extension communication mode for relaying communication between the mobile station B and the mobile station B is performed.

In a wireless communication system in which communication between mobile units is performed according to the above-described procedure, each mobile unit synchronizes with the control channel of the communication control unit 50 in both the communication mode between the mobile units and the extension communication mode. Since standby is possible, intermittent reception is facilitated. Therefore, it is not necessary to continuously or frequently monitor the standby channel in order to perform communication in the communication mode between slave units, and it is possible to reduce power consumption.

Further, since the standby in the communication mode between the slave units and the extension communication mode is performed on the control channel from the communication control device 50, the call is reliably received in any communication mode, and The connection quality between them is improved. Furthermore,
When the communication control device 50 receives the call on the control channel, the communication control device 50 switches to the communication mode between the child devices when the communication in the communication mode between the child devices is permitted. The communication traffic in the extension communication mode to be performed is reduced, and the communication quality in the extension communication mode is improved.

Further, when the positional relationship between the mobile devices is not possible in the communication mode between the mobile devices, the communication is automatically switched to the communication in the extension communication mode. The quality will be more stable. In the wireless communication system described above, each of the mobile devices 10, 11,.
12 communicates via the public line network NW (public communication)
In this case, the communication control device 50 converts the public communication into the private communication, and relays the wireless communication between each of the mobile devices 10, 12, and 13 having no public contract and another communication terminal via the public network NW. .

Although the PHS has been described in the above-described example, the present invention is not limited to the PHS but is also applicable to a wireless communication system including a plurality of other mobile devices and a communication control device for controlling the mobile devices. be able to.

[0040]

As described above, according to the present invention as set forth in claims 1 to 4, a call for performing wireless communication using any of the first and second communication modes is reliably received. This eliminates the necessity of constantly or frequently confirming a call in the second communication mode for performing direct wireless communication between mobile devices. Then, it is possible to reduce communication traffic in the first communication mode in which wireless communication between mobile devices is performed by relaying the communication control device, and to improve connection quality of wireless communication relaying the communication control device. As a result, it is possible to realize a wireless communication system in which communications in the first communication mode and the second communication mode can be used efficiently.

According to the fifth to eighth aspects of the present invention, it is possible to realize a communication control device used in the above-described wireless communication system. Further, claims 9 to 1
According to the sixth aspect of the present invention, it is possible to realize a mobile device used in the above wireless communication system.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a wireless communication system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a configuration of a communication control device and each mobile device when attention is paid to private communication in the wireless communication system illustrated in FIG. 1;

FIG. 3 is a sequence diagram illustrating an example of a communication procedure between the communication control device and each mobile device.

FIG. 4 is a sequence diagram showing another example of a communication procedure between the communication control device and each mobile device.

[Explanation of symbols]

 10, 11, 12 Mobile device (slave device) 21, 31, 51 Control device 22, 32, 52 Transmitter 23, 33, 53 Receiver 50 Communication control device 100 Private communication area 150 Base station

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hideo Matsuki 2-10-1 Toranomon, Minato-ku, Tokyo NTT Mobile Communications Network Co., Ltd. (72) Inventor Hideyuki Matsutani 2-chome Toranomon, Minato-ku, Tokyo No. 10 No. 1 F-term in NTT Mobile Communication Network Co., Ltd. (reference)

Claims (16)

[Claims] 1. A communication control device, comprising: a plurality of mobile devices that are in a standby state on a control channel from the communication control device;
Each mobile device can have a first communication mode for performing wireless communication via a communication control device when a call is received on a control channel, and a second communication mode for performing direct wireless communication between mobile communication devices. In a wireless communication system, when the communication control device receives a call from a first mobile device to a second mobile device on a control channel, the communication control device transmits the control channel to the first and second mobile devices. A communication mode switching instructing means for transmitting a control signal for instructing switching to the second communication mode at the first and second mobile devices that have received the control signal on the control channel from the communication control device, A wireless communication system configured to perform wireless communication in a second communication mode according to the instruction. 2. The wireless communication system according to claim 1, wherein the control signal transmitted from the communication mode switching instruction means of the communication control device to the first mobile station includes an instruction to switch to the second communication mode. An instruction for recalling in the second communication mode for the second mobile station is included, and the first mobile station responds to the instruction for recalling in the second communication mode in the second communication mode. A wireless communication system for performing a recall. 3. The wireless communication system according to claim 1, wherein the control signal transmitted from the communication mode switching instructing means of the communication control device to the first and second mobile stations changes to the second communication mode. Along with the switching instruction, includes designation of a wireless channel used for communication in the second communication mode, and the first and second mobile stations use the designated wireless channel in the second communication mode. A wireless communication system adapted to perform wireless communication. 4. The wireless communication system according to claim 1, wherein the communication mode switching instructing means of the communication control device performs a second communication when the first mobile device calls the second mobile device. A wireless communication system configured to transmit a control signal instructing the first and second mobile stations to switch to a second communication mode when a message that permits communication in the mode is included. 5. A communication control apparatus, comprising: a plurality of mobile stations which are on standby on a control channel from the communication control apparatus;
Each mobile device can have a first communication mode for performing wireless communication via a communication control device when a call is received on a control channel, and a second communication mode for performing direct wireless communication between mobile communication devices. The communication control device used in the wireless communication system, wherein when a call from the first mobile device to the second mobile device is received on a control channel, the control for the first and second mobile devices is performed. Communication mode switching instructing means for transmitting a control signal for instructing switching to the second communication mode by a channel, and by this control signal, switching to the second communication mode for the first and second mobile devices. A communication control device for performing wireless communication. 6. The communication control device according to claim 5, wherein the control signal transmitted from the communication mode switching instructing means to the first mobile unit is transmitted together with the instruction to switch to the second communication mode. A communication control apparatus including an instruction for recalling in a second communication mode to the mobile device, and causing the first mobile device to recall in the second communication mode for the second mobile device. 7. The communication control device according to claim 5, wherein the control signal transmitted from the communication mode switching instructing means to the first and second mobile stations includes an instruction to switch to the second communication mode, Including a designation of a wireless channel used for communication in the second communication mode, causing the first and second mobile stations to perform wireless communication in the second communication mode using the designated wireless channel. Communication control device. 8. The communication control device according to claim 5, wherein the communication mode switching instructing means performs communication in a second communication mode when the first mobile device calls the second mobile device. A communication control device configured to transmit a control signal for instructing the first and second mobile stations to switch to a second communication mode when an allowable message is included. 9. A communication control apparatus, comprising: a plurality of mobile stations which are on standby on a control channel from the communication control apparatus;
Each mobile device can have a first communication mode in which wireless communication is performed via a communication control device when a call is received on a control channel, and a second communication mode in which mobile devices directly perform wireless communication with each other. A communication mode for switching a communication mode to a second communication mode when receiving a control signal instructing switching to a second communication mode from a communication control device on a control channel in a mobile device used in a wireless communication system. The communication mode switching means when the control signal is received from the communication control apparatus after transmitting a call to another mobile station on a control channel from the communication control apparatus. A mobile device that starts communication with the other mobile device in the communication mode. 10. A mobile station according to claim 9, wherein said communication mode switching means switches said communication mode when said control signal is received from said communication control unit without transmitting a call to another mobile station. A mobile station which is set to a standby state on a predetermined standby channel in the second communication mode. 11. The mobile device according to claim 9, wherein the communication control device issues an instruction to switch to the second communication mode, and also instructs the second mobile device to recall in the second communication mode. And receiving a control signal including the following in accordance with the instruction, and recalling the other mobile device in the second communication mode switched by the communication mode switching means. 12. The mobile station according to claim 9, wherein a command for switching to the second communication mode from the communication control device and a designation of a wireless channel used for communication in the second communication mode. A mobile unit configured to perform wireless communication with another mobile unit in the second communication mode switched by the communication mode switching unit using the specified wireless channel when receiving a control signal including the control signal. . 13. The mobile device according to claim 9, wherein when a call is made to another mobile device on a control channel from the communication control device, communication in the second communication mode is performed for the call. A mobile device that includes a message to allow. 14. The mobile station according to claim 9, wherein communication in the second communication mode is possible after the communication mode is switched to the second communication mode by the communication mode switching means. A mobile device having a determination unit for determining whether or not communication in the second communication mode is not possible when the determination unit determines that communication in the second communication mode is not possible; . 15. The mobile station according to claim 14, wherein said determination means transmits a call to another mobile station via a control channel from the communication control apparatus, and thereafter performs communication based on the control signal from the communication control apparatus. When the communication mode is switched to the second communication mode by the mode switching means,
A first timer that is activated on the basis of the call in the second communication mode, and a second communication mode when a time measured by the timer reaches a predetermined time before a response to the call is received. A mobile device that determines that communication is not possible. 16. The mobile station according to claim 14, wherein said determination means communicates by a communication mode switching means based on said control signal from a communication control device without transmitting a call to another mobile equipment. A second timer that starts when the mode is switched to the second communication mode based on the switching of the communication mode, and performs a second communication when the time measured by the timer reaches a predetermined time. A mobile device that determines that communication in the mode is not possible.