JP2000209633A - Mobile radio communication system and mobile radio terminal - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a mobile radio communication system by which communication can be continued through packet exchange connection even when communication by line exchange connection cannot be continued in a radio base station at a moving destination in the case of hand-over. SOLUTION: A resource transmission control means 111a in each of radio base stations BS1-BSn detects an operating state of a resource to respectively conduct line exchange connection and packet exchange connection in its own station and informs a mobile radio terminal PS of it. Resource information received from the radio base stations BS1-BSn is stored in a resource information storage area 121c of the mobile radio terminal PS. Moreover, a call control means 121a makes a call on the basis of the resource information. A hand-over control means 121b conducts hand-over control and sets up a communication link of exchange connection of a type based on the resource information received from a radio base station of a moving destination.

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 system for connecting a mobile radio terminal device to a communication network by using one of circuit-switched connection and packet-switched connection. The present invention relates to a mobile radio terminal device used in a mobile terminal.

[0002]

2. Description of the Related Art As is well known, a conventional mobile radio communication system has a circuit-switched connection and a packet-switched connection as modes for connecting a mobile radio terminal (hereinafter referred to as a mobile station) to a communication network. There is something.

[0003] A circuit-switched connection is a connection form in which a terminal occupies a line between a call and a call being disconnected, and is suitable mainly for real-time communication of continuous information such as voice and video. ing.

[0004] A packet-switched connection is a connection mode in which a line is occupied only when packetized data is transmitted. Packets to be transmitted are temporarily stored in a packet switch, and are sequentially transferred according to routing. The data is transmitted to the communication partner terminal via the exchange. This connection form is mainly applied to communication with low real-time requirements such as data communication.

[0005] In a conventional mobile radio communication system,
These switched connection types are determined at the time of call setup, and once set, the connection type is not changed until the call is disconnected.

In a conventional mobile radio communication system, when a mobile station connected in a circuit-switched manner moves between cells to perform a handover, communication by circuit-switched connection can be continued through a destination base station. In some cases, the call was disconnected.

[0007] This is because the communication time of the circuit-switched connection is longer than that of the packet-switched connection. It is caused by

In addition, when a mobile station makes a call for performing a circuit-switched connection and the radio for the circuit-switched connection has no vacancy as described above, the call request cannot be accepted. In some cases, communication could not be performed.

[0009]

In a conventional mobile radio communication system, for example, in a radio base station forming a destination radio zone at the time of handover, if all radios for circuit-switched connection are in use, There has been a problem that communication by circuit-switched connection cannot be continued through the destination wireless base station, and the call is disconnected.

[0010] The present invention has been made to solve the above-mentioned problem. Even when communication at a destination radio base station cannot be continued by circuit-switched connection at the time of handover, communication is continued by packet-switched connection. It is an object of the present invention to provide a mobile radio communication system capable of performing such operations.

Further, in the conventional mobile radio terminal, when a call for performing circuit-switched connection is made, for example, if there is no free space in the circuit-switched connection radio of the radio base station, a call request is issued. There was a problem that communication could not be performed due to being not accepted.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problem. Even when a radio base station does not accept a call request for performing a circuit-switched connection, communication can be started by a packet-switched connection. An object is to provide a mobile wireless terminal device.

[0013]

In order to achieve the above-mentioned object, the present invention provides a mobile radio terminal which is connected to a radio base station connectable to a communication network through a radio line, and stores packetized data. A packet-switched communication in a mobile radio communication system that selectively performs packet-switched communication in which communication is performed exclusively by transmitting a line and communication in which the line is constantly occupied. Information transmitting means for transmitting, to the mobile radio terminal apparatus, information indicating whether or not communication between the base station and the circuit-switched communication is possible, the mobile radio terminal apparatus comprises: a receiving means for receiving information; When performing circuit-switched communication through a station, if the information received by the receiving means indicates that circuit-switched communication is not possible, substitute for circuit-switched communication. And to constitute comprises a communication means for performing packet switching type communication.

[0014] In order to achieve the above object, the present invention provides a method for connecting a wireless base station connectable to a communication network through a wireless line and occupying the line only when transmitting packetized data. In a mobile wireless terminal device for selectively performing packet-switched communication for performing communication and circuit-switched communication for performing communication while constantly occupying a line,
A receiving means for receiving information indicating whether packet-switched communication and circuit-switched communication are possible in the wireless base station from the wireless base station, and receiving means for performing circuit-switched communication through the wireless base station. Communication means for performing packet-switched communication in place of circuit-switched communication when the information received by the means indicates that circuit-switched communication is not possible. .

[0015] In the mobile radio communication system and the mobile radio terminal device having the above-described configuration, when performing circuit-switched communication through the radio base station, the information received by the receiving means indicates that the circuit-switched communication is not possible. If it was,
Packet-switched communication is performed instead of circuit-switched communication.

Therefore, according to the mobile radio communication system and the mobile radio terminal having the above configuration, even if the radio base station does not accept a call request for performing a circuit-switched connection,
Communication can be initiated by a packet-switched connection.

According to another aspect of the present invention, a mobile radio terminal is connected to a radio base station connectable to a communication network through a radio line and transmits packetized data. In a mobile radio communication system that selectively performs packet-switched communication in which communication is performed exclusively by occupying a line and circuit-switched communication in which communication is performed by constantly occupying a line, packet-switched communication and circuit-switched communication are performed. Information transmitting means for transmitting information indicating whether or not communication is possible in the radio base station to the mobile radio terminal apparatus, the mobile radio terminal apparatus receives the information, and performs circuit switching through the radio base station. When performing handover to a destination wireless base station while performing type communication, the information received by the receiving means is used for circuit switching type communication at the destination wireless base station. If was an indication that it is possible, and to constitute comprises a communication means for performing a handover by performing alternative packet-switched communication to the destination radio base station and the circuit switched communications.

Further, in order to achieve the above object, the present invention connects to a radio base station connectable to a communication network through a radio line, and occupies the line only when transmitting packetized data. In a mobile wireless terminal device that selectively performs packet-switched communication in which communication is performed by communication and circuit-switched communication in which communication is performed by occupying a line constantly, packet-switched communication and circuit-switched Communication means for receiving information indicating whether or not communication is possible in the radio base station, and receiving means for performing handover to a destination radio base station while performing circuit-switched communication through the radio base station. If the information received at the above indicates that circuit-switched communication is not possible at the destination wireless base station, And to constitute comprises a communication means for performing a handover by performing alternative packet-switched communications.

In the mobile radio communication system and the mobile radio terminal device having the above-mentioned configurations, when performing handover to a destination radio base station while performing circuit-switched communication through the radio base station, information received by the receiving means is not transmitted. If the signal indicates that circuit-switched communication is not possible at the target wireless base station, handover is performed by performing packet-switched communication instead of circuit-switched communication with the target wireless base station. I'm trying to do it.

Therefore, according to the mobile radio communication system and the mobile radio terminal device having the above-described configuration, even when communication at the destination radio base station cannot be continued at the destination radio base station at the time of handover, communication is performed by packet-switched connection. Can be continued.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a configuration of a mobile radio communication system according to a first embodiment of the present invention.

The mobile radio communication system has a radio network NW1, a control station CS, radio base stations BS1 to BSn, and a mobile radio terminal (mobile station) PS as main components.
Consists of

The control station CS controls the radio base stations BS1 to BSn through the radio network NW1.
The location information of the mobile radio terminal PS is managed based on the location registration information notified from the radio base stations BS1 to BSn. Then, the control station CS determines that the mobile radio terminal PS
When moving between the wireless zones formed by the wireless base stations BS1 to BSn, the wireless base stations B of the movement source and the movement destination
An instruction is given to each of S1 to BSn to perform a handover process for switching the wireless base station with which the mobile wireless terminal device PS communicates.

Each of the radio base stations BS1 to BSn forms a wide communication area by a radio zone (cell) to be formed, establishes a radio link with the mobile radio terminal PS, and connects the mobile radio terminal PS. Wireless network NW
1 and is connected to the wired network NW2, and includes a communication unit 110 and a control unit 111 as main components.

The communication unit 110 is used for transmitting and receiving packetized data to and from a plurality of mobile radio terminals PS through a radio line through a radio line. A packet-switched connection in which communication is performed by occupying only the communication link is selectively performed in accordance with an instruction from the control unit 111.

The control unit 111 includes a CPU, a ROM and an R
AM, etc., wherein the CPU is the RO
M, according to a control program and control data stored in the M.
And a resource information transmission control unit 111a realized by the software processing.

The resource information transmission control means 111a detects the use status of resources (radio equipment and channels of the communication unit) for performing the circuit-switched connection and the packet-switched connection in its own station. It is determined whether a circuit-switched connection and a packet-switched connection are possible. Then, the result of this determination is used as resource information.
The communication unit 110 is controlled to perform transmission to the mobile wireless terminal device PS.

On the other hand, the mobile radio terminal PS has a communication unit 120, a control unit 121, and a display unit 12 as main components.
2 and a key input unit 123. The communication unit 120
A circuit-switched connection and a packet-switched connection are selectively performed through a wireless line with the wireless base station BS in accordance with an instruction from the control unit 111.

The control unit 121 includes a CPU, a ROM, and an R
AM, etc., wherein the CPU is the RO
M controls the respective units in accordance with a control program and control data stored in the M.
Call control means 121 realized by software processing
a, a handover control unit 121b, and a resource information storage area 121c in the RAM.

The call control means 121a, when a user's request or the control unit 121 executes an application program (hereinafter referred to as an application), makes the request, the application, and the radio base station BS1 to be connected.
To make a type of switching connection in accordance with the resource information received from BSn to BSn,
A communication link is established with Sn.

The handover control means 121b performs handover control for communicating through the destination radio base stations BS1 to BSn.
A communication link of a switching connection of a type based on the resource information received from the radio base station is established between the communication base stations 1 to BSn.

The resource information storage area 121c is an area for storing the resource information received by the communication section 120 from the radio base stations BS1 to BSn.

Next, the operation of the mobile radio communication system having the above configuration will be described. 2 and 4 are diagrams showing a communication sequence performed between the mobile radio terminal apparatus PS and the radio base stations BS1 and BS2.

First, in the case where the mobile radio terminal PS makes a call requesting circuit-switched communication in a state where resources for performing circuit-switched communication are insufficient in the radio base station BS1. The operation will be described. FIG. 2 shows the sequence.

First, in the radio base station BS1, the resource information transmission control means 111a performs, at a predetermined cycle, resources (wireless units and channels of the communication unit) for performing circuit-switched connection and packet-switched connection in its own station. )
, And determines whether a circuit-switched connection and a packet-switched connection are possible through its own station.
Then, control is performed to control and transmit the communication unit 110 using the result of this determination as resource information.

At this time, as shown in FIG. 3, if the mobile radio terminal PS is in the radio zone of the radio base station BS1,
The mobile radio terminal device PS receives the resource information transmitted from the radio base station BS1 by the communication unit 120, and records the resource information in the resource information storage area 121c. The state so far is defined as S1.

As shown in FIG. 5, the resource information acquired by the mobile radio terminal PS from the radio base station BS1 indicates that the circuit-switched connection is "impossible" and the packet-switched connection is "possible". ".

In this state S1, in the mobile radio terminal PS, when the user requests a call through the key input unit 123, or when the control unit 121 activates an application to request a call, the call is made. Control means 121
a refers to the resource information recorded in the resource information storage area 121c.

At this time, since the resource information indicates that the circuit-switched connection is "impossible" as described above, the call control means 121a controls the communication unit 120 to execute the circuit-switched connection. Instead, a call setting request for performing a packet-switched connection is made to the radio base station BS1.

When a call is requested by the application, since the application does not specify the communication type, the circuit-switched connection is prioritized by setting the circuit-switched connection to be prioritized. .

On the other hand, when the radio base station BS1 receives the call setting request from the mobile radio terminal device PS in the communication unit 110, the communication unit 110 makes available resources for performing packet-switched connection. Therefore, a response message indicating that the call setting request from the mobile wireless terminal device PS has been received is transmitted to the mobile wireless terminal device PS.

Thus, a radio communication link for performing packet-switched communication is established between mobile radio terminal PS and radio base station BS1, and communication by packet-switched connection is started (state). S2).

Next, a description will be given of an operation in a case where a handover is performed in a state where communication by circuit switching connection is being performed in mobile radio terminal apparatus PS. FIG. 4 shows the sequence.

First, in the radio base station BS1, the resource information transmission control means 111a performs, at a predetermined cycle, resources (wireless units and channels of the communication unit) for performing circuit-switched connection and packet-switched connection in its own station. ) Is detected, and it is determined whether a circuit-switched connection and a packet-switched connection are possible through its own station. Then, the communication unit 1 uses the result of this determination as resource information.
10 to control transmission.

At this time, as shown in FIG. 3, when the mobile radio terminal PS is in the radio zone of the radio base station BS1,
The mobile radio terminal device PS receives the resource information transmitted from the radio base station BS1 by the communication unit 120, and records the resource information in the resource information storage area 121c. The state so far is defined as S1 '.

Here, the resource information obtained by the mobile radio terminal PS from the radio base station BS1 includes, as shown in FIG.
It is assumed that both indicate "possible".

In this state S1 ', when the user requests a call through the key input unit 123 in the mobile radio terminal device PS, or when the control unit 121 activates an application to request a call, the call is made. Call control means 12
1a refers to the resource information recorded in the resource information storage area 121c.

At this time, since the resource information indicates "possible" for both the circuit-switched connection and the packet-switched connection as described above, the call control means 121a
Controls the communication unit 120 to make a call setting request to the radio base station BS1 for making a circuit-switched connection.

When a call is requested by the application, since the application does not specify the communication type, the circuit-switched connection is preferentially performed by setting the circuit-switched connection to be prioritized. It shall be assumed.

On the other hand, when radio base station BS1 accepts a call setting request from mobile radio terminal apparatus PS in communication section 110, communication section 110 has a vacant resource for circuit-switched connection. Therefore, a response message indicating that the call setting request from the mobile wireless terminal device PS has been received is transmitted to the mobile wireless terminal device PS.

Thus, a radio communication link for performing circuit-switched communication is established between mobile radio terminal PS and radio base station BS1, and communication by circuit-switched connection is started (state). S2 ').

From this state S2 ', the mobile radio terminal P
S, and as shown in FIG.
When S reaches both the radio zones of the radio base stations BS1 and BS2, the mobile radio terminal PS receives the resource information transmitted from the radio base station BS2 by the communication unit 120, and stores the resource information in the resource information storage area. 121
Record in c. This state is defined as S3.

Here, the resource information acquired by the mobile radio terminal PS from the radio base station BS2 indicates that the circuit-switched connection is "impossible" and the packet-switched connection is "not available" as in FIG. "Possible".

When the mobile radio terminal PS further moves and needs to be handed over from the radio base station BS1 to the radio base station BS2, the handover control means 1
21b performs handover control.

Here, the handover control means 121b
Performs handover control with reference to the resource information acquired from the above-described radio base station BS2 and recorded in the resource information storage area 121c.

However, here, in the resource information,
Since the current circuit-switched connection is “impossible”, the handover control unit 121 b
0 to make a call setting request for performing a packet-switched connection instead of a circuit-switched connection.
Do for

On the other hand, when the radio base station BS2 accepts the call setting request from the mobile radio terminal device PS in the communication unit 110, the communication unit 110 makes available resources for packet-switched connection. Therefore, a response message indicating that the call setting request from the mobile wireless terminal device PS has been received is transmitted to the mobile wireless terminal device PS.

As a result, a radio communication link for performing packet-switched communication is established between mobile radio terminal PS and radio base station BS2, and communication by packet-switched connection is started (state). S4).

Thereafter, the mobile radio terminal PS establishes a radio communication link for performing packet-switched communication with the radio base station BS2.
Request to disconnect the circuit-switched communication link.

On the other hand, the radio base station BS1 accepts the above request from the mobile radio terminal PS and disconnects the circuit-switched communication link established with the mobile radio terminal PS (state). S5).

As described above, in the mobile radio communication system having the above-described configuration, the mobile radio terminal device PS previously acquires resource information from the connectable radio base station BS1, and uses this resource information to link with the radio base station BS1. If it is known that the communication of the switched connection cannot be performed, the communication is performed by the packet switched connection instead of the communication by the circuit switched connection.

Therefore, according to the mobile radio communication system having the above configuration, even when the radio base station does not accept the call request for performing the circuit-switched connection, the communication can be started by the packet-switched connection.

Further, in the mobile radio communication system having the above configuration, before the mobile radio terminal PS performs a handover,
If resource information is acquired from the destination radio base station BS2 and it is known from the resource information that communication with the radio base station BS2 cannot be continued by circuit switching connection, the connection is replaced by circuit switching connection. Therefore, communication is performed by a packet switching type connection.

Therefore, according to the mobile radio communication system having the above-described configuration, even when communication at the destination radio base station BS2 cannot be continued at the time of handover, communication can be continued at the packet switched connection. Can be.

The present invention is not limited to the above embodiment. For example, in the above embodiment, when communication by circuit-switched connection is not possible or cannot be continued, communication by packet-switched connection is automatically performed instead of circuit-switched connection.

However, instead of this, for example, when the communication by the circuit-switched connection is not possible or cannot be continued, the user can use the display unit 122 of the mobile radio terminal PS to give the user a packet-switched connection instead of the circuit-switched connection. May be performed, and communication may be performed by packet-switched connection in response to a response from the user through the key input unit 123.

Further, when the communication by the packet switching type connection is performed instead of the communication by the circuit switching type connection, and then, when the resource information enabling the circuit switching type connection is obtained from the connected radio base station. For example, the communication by the circuit-switched connection may be performed again instead of the communication by the packet-switched connection. In addition, it goes without saying that various modifications can be made without departing from the scope of the present invention.

[0068]

As described above, according to the present invention, when performing circuit-switched communication through a radio base station, the information received by the receiving means indicates that circuit-switched communication is not possible. If there is, packet-switched communication is performed instead of circuit-switched communication.

Therefore, according to the present invention, a mobile radio communication system and a mobile radio system capable of starting communication by packet-switched connection even when the radio base station does not accept a call request for circuit-switched connection. A terminal device can be provided.

Further, according to the present invention, when performing handover to a destination radio base station while performing circuit-switched communication through the radio base station, information received by the receiving means is transmitted to the destination radio base station by the destination means. When it indicates that the circuit-switched communication is not possible, the handover is performed by performing packet-switched communication instead of the circuit-switched communication with the destination wireless base station.

Therefore, according to the present invention, the mobile radio communication which can continue the communication by the packet-switched connection even if the communication by the circuit-switched connection cannot be continued at the destination radio base station at the time of the handover. A system and a mobile wireless terminal can be provided.

[Brief description of the drawings]

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

FIG. 2 is a view showing a sequence when a call is made in the mobile radio communication system shown in FIG.

FIG. 3 is a diagram showing a mobile wireless terminal device PS located in a wireless zone formed by the wireless base station BS1 shown in FIG. 1;

FIG. 4 is a diagram showing a sequence at the time of calling and handover of the mobile radio communication system shown in FIG. 1;

FIG. 5 is a diagram showing resource information notified to the mobile radio terminal device PS in the sequences shown in FIGS. 2 and 4;

FIG. 6 is a diagram showing resource information notified to the mobile radio terminal device PS in the sequence shown in FIG. 4;

FIG. 7 is a diagram showing a state where the mobile radio terminal PS shown in FIG. 1 moves from a radio zone formed by the radio base station BS1 to a radio zone formed by the radio base station BS2.

[Explanation of symbols]

 110 communication unit 111 control unit 111a resource information transmission control unit 120 communication unit 121 control unit 121a call control unit 121b handover control unit 121c resource information storage area 122 display unit 123 key input unit BS1 ＢＳBSn: Radio base station CS: Control station NW1: Wireless network NW2: Wired network PS: Mobile radio terminal

Claims (12)

[Claims] 1. A mobile wireless terminal device is connected to a wireless base station connectable to a communication network via a wireless line,
A mobile radio communication system that selectively performs packet-switched communication in which communication is performed by occupying a line only when transmitting packetized data and circuit-switched communication in which communication is performed by constantly occupying a line. In the information transmission means for transmitting to the mobile radio terminal device information indicating whether or not the packet-switched communication and the circuit-switched communication are each possible in the radio base station, Receiving means for receiving the information, and when performing circuit-switched communication through the wireless base station,
Communication means for performing packet-switched communication instead of circuit-switched communication when the information received by the receiving means indicates that circuit-switched communication is not possible. Mobile radio communication system. 2. The communication means performs packet-switched communication instead of circuit-switched communication, and the information received by the receiving means indicates that circuit-switched communication is possible. 2. The mobile radio communication system according to claim 1, wherein circuit-switched communication is performed in place of packet-switched communication. 3. When the communication means performs circuit-switched communication through the radio base station, the information received by the receiving means indicates that circuit-switched communication is not possible. 2. The mobile radio communication system according to claim 1, wherein packet-switched communication is performed instead of circuit-switched communication according to a user's intention of the mobile radio terminal. 4. A mobile wireless terminal device is connected to a wireless base station connectable to a communication network via a wireless line,
A mobile radio communication system that selectively performs packet-switched communication in which communication is performed by occupying a line only when transmitting packetized data and circuit-switched communication in which communication is performed by constantly occupying a line. In the information transmission means for transmitting to the mobile radio terminal device information indicating whether or not the packet-switched communication and the circuit-switched communication are each possible in the radio base station, Receiving means for receiving the information, while performing circuit-switched communication through the wireless base station, when performing a handover to a destination wireless base station, the information received by the receiving means, the destination of the destination, If the wireless base station indicates that circuit-switched communication is not possible, packet-switched communication is performed instead of circuit-switched communication with the destination wireless base station. And a communication means for performing a handover by performing the operation. 5. The communication means, wherein after performing a handover by packet-switched communication instead of circuit-switched communication, the information received by the receiving means indicates that circuit-switched communication is possible. 5. The mobile radio communication system according to claim 4, wherein, when the packet communication is performed, the circuit switching communication is performed instead of the packet switching communication. 6. The communication means, when performing a handover to a destination wireless base station while performing circuit-switched communication through the wireless base station, the information received by the receiving means, If the wireless base station indicates that circuit-switched communication is not possible, the mobile base station may replace the circuit-switched communication with the destination wireless base station according to the user's intention. The mobile radio communication system according to claim 4, wherein the handover is performed by performing packet switching communication. 7. A packet-switched communication in which a wireless base station which can be connected to a communication network is connected through a wireless line to occupy the line only when transmitting packetized data, In a mobile radio terminal device that selectively performs circuit-switched communication that occupies and communicates, the packet-switched communication and the circuit-switched communication can be performed in the wireless base station from the wireless base station, respectively. Receiving means for receiving information indicating whether or not, when performing circuit-switched communication through the wireless base station,
Communication means for performing packet-switched communication instead of circuit-switched communication when the information received by the receiving means indicates that circuit-switched communication is not possible. Mobile radio terminal device. 8. The communication means performs packet-switched communication instead of circuit-switched communication, and the information received by the receiving means indicates that circuit-switched communication is possible. 8. The mobile radio terminal device according to claim 7, wherein in that case, circuit-switched communication is performed instead of packet-switched communication. 9. When the communication means performs circuit-switched communication through the radio base station, the information received by the receiving means indicates that the circuit-switched communication is not possible. 8. The mobile radio terminal according to claim 7, wherein packet-switched communication is performed instead of circuit-switched communication according to a user's intention of the mobile radio terminal. 10. A packet-switched communication in which a wireless base station which can be connected to a communication network is connected through a wireless line to occupy the line only when transmitting packetized data and performs communication, In a mobile radio terminal device that selectively performs circuit-switched communication that occupies and communicates, the radio base station allows the packet-switched communication and the circuit-switched communication to be performed in the radio base station, respectively. Receiving means for receiving information indicating whether or not, while performing circuit-switched communication through the wireless base station, when performing a handover to a destination wireless base station, the information received by the receiving means, the If it indicates that circuit-switched communication is not possible at the destination wireless base station, the packet is exchanged with the destination wireless base station instead of circuit-switched communication. Mobile radio terminal apparatus characterized by comprising a communication means for performing a handover by performing switching type communication. 11. The communication means, wherein after performing a handover by packet-switched communication instead of circuit-switched communication, the information received by the receiving means indicates that circuit-switched communication is possible. 11. The mobile radio terminal device according to claim 10, wherein when the communication is performed, circuit-switched communication is performed instead of packet-switched communication. 12. The communication unit, when performing a handover to a destination wireless base station while performing circuit-switched communication through the wireless base station, the information received by the receiving unit may be the information of the destination. If the signal indicates that circuit-switched communication is not possible in the wireless base station, the wireless base station may replace the circuit-switched communication with the destination wireless base station according to the user's intention of the mobile wireless terminal device. The mobile radio terminal according to claim 10, wherein the handover is performed by performing packet-switched communication.