JP4809407B2 - Mobile communication system, radio network apparatus and method - Google Patents

Description

  The present invention generally belongs to the technical field of mobile communication, and particularly relates to a mobile communication system, a radio network apparatus and a method for processing a reconnection request signal from a radio terminal.

  In the IMT-2000 system, a communication path is established between a core network (CN), a radio network controller (RNC), a radio base station (BTS), and a radio terminal (UE). Done in One or more radio network controllers (RNCs) belong to a switch belonging to the core network (CN). One or more radio base stations (BTS) belong to the radio network controller (RNC). The range covered by radio waves of each radio base station (BTS) is called a cell. A radio terminal (UE) performs handover between cells and / or between RNCs as necessary.

  Regarding handover between RNCs, there is a method called a subscriber line extension method from the viewpoint of reducing the number of handovers. In the case of this method, even if a wireless terminal that has set an individual channel under “a certain RNC” moves to an area under “another RNC”, the communication control of the wireless terminal is still “a certain RNC”. Control signals exchanged between the “certain RNC” and the wireless terminal are transmitted / received via “another RNC”. The “certain RNC” in this case is referred to as a serving RNC (Serving-RNC), and is a radio network controller in which a radio terminal first connects a dedicated channel. “Another RNC” is referred to as Drift-RNC and relays signals between the serving RNC and the wireless terminal. As described above, in the subscriber line extension method, the wireless terminal is connected to the core network (CN) via one or more RNCs. For example, Patent Document 1 describes the extension of a subscriber line in a CDMA mobile communication system.

  When a radio terminal requests a handover to a cell under the drift RNC, a predetermined handover process must be performed between the serving and the drift RNC. However, when the wireless terminal is moving at high speed, there is a possibility that inconvenience may occur due to a delay in connection processing between the serving RNC and the drift RNC. For example, the wireless terminal moves to a cell on the drift RNC side before an instruction for permitting a handover is transmitted from the serving RNC to the wireless terminal, and in this case, there is a concern about deterioration of communication quality. When communication quality deteriorates to such an extent that connection cannot be maintained, reconnection processing needs to be performed. This reconnection processing also requires a certain amount of time. Even if the reconnection process itself succeeds, the connection does not sufficiently reflect the most recent state of the wireless terminal (due to high-speed movement), so in the state immediately after the reconnection process, Communication quality between wireless network control devices is not yet stable. For this reason, reconnection processing is required again, and there is a concern about the vicious circle that leads to reconnection processing one after another. In the worst case, there is a concern that communication may be disconnected.

By the way, from the viewpoint of eliminating the delay between the serving and drift RNCs, there is a SRNS-Relocation method in which the serving RNC is switched every time the wireless terminal moves to an RNC area other than the serving RNC. Unlike the subscriber line extension method, in the SRNS relocation method, the RNC (serving RNC) that controls communication of the wireless terminal is switched as the wireless terminal moves. Accordingly, there is a concern that the frequency of switching the serving RNC is higher than in the case of the subscriber line extension method, and the processing burden on the network side increases. Furthermore, when switching the serving RNC, there is a concern that communication may not be continuous at the moment of switching. The SRNS relocation method is described in Patent Document 2, for example.
JP 2001-25046 A JP 2005-260435 A

  As described above, since the subscriber line extension method prevents the serving RNC from being switched as much as possible, the communication is hardly interrupted. Therefore, the subscriber line extension method is suitable for voice packet (VoIP) and real-time data communication. However, since there are a plurality of RNCs on the communication path of the control signal, there is a concern about delay of the control signal. This delay is particularly undesirable when dealing with reconnections. Since there is only one RNC intervening in the communication path in the SRNS relocation method, the control signal delay which is a concern in the subscriber line extension method does not occur theoretically. However, since the serving RNC is switched every time the wireless terminal enters an RNC area different from the serving RNC, there is a concern that the frequency of switching increases and the processing load on the network side increases.

  The problem of the present application is that when a wireless terminal requests reconnection after connecting to a radio network controller (RNC), reconnection to that RNC or another RNC without excessively increasing the processing burden on the network side. To improve the success rate.

In one form of the present invention, one or more radio base stations and a radio network controller connected to the core network are used. The wireless network control device
A communication control unit for controlling communication of the wireless terminal;
Subscription to receive signals from and transmit signals to the other radio network control devices so that signals are transmitted to and received from the radio terminals via the other radio network control devices The person line extension processing department,
And the reconnection request signal transmitted from the wireless terminal is received via the other wireless network control device, the wireless network control device, the other wireless network control device, and the If the communication control unit has not confirmed that a communication path has been established between wireless terminals,
The wireless network control device is configured to notify the core network that the communication control of the wireless terminal is to be performed by the other wireless network control device.

  According to the present invention, when a wireless terminal requests reconnection after connecting to a radio network controller (RNC), reconnection to that RNC or another RNC without excessively increasing the processing burden on the network side The success rate can be improved.

  In one form of the invention, a radio network controller (RNC) that controls the reconnection process is used. The RNC has a communication control unit (or may be referred to as a wireless terminal information management unit), analyzes a reconnection request signal reported from the wireless terminal, and determines whether or not the wireless terminal is in a predetermined area. Then, it is determined whether or not the reconnection is due to a failure of the subscriber line extension type handover. The predetermined area may be, for example, a cell group under the RNC or a cell group under a specific exchange. Further, the handover in this case is a handover in the subscriber line extension method, that is, a handover in which the drift RNC is appropriately changed without changing the serving RNC. If the “predetermined condition” is not satisfied as a result of the analysis of the reconnection request signal, the RNC reestablishes a communication path by the subscriber line extension method according to the received reconnection request signal. The “predetermined condition” is, for example, that the wireless terminal is located in a region other than the predetermined region, and that the cause of the reconnection is that the subscriber line extension type handover has failed. If the predetermined condition is satisfied as a result of the analysis of the reconnection request signal, the RNC establishes a communication path by the SRNS relocation method according to the received reconnection request signal.

  The above-mentioned “predetermined condition” is that the wireless terminal is located outside the predetermined area, and the cause of the reconnection is that the subscriber line extension type handover has failed. Therefore, the number of times that the “predetermined condition” is satisfied is relatively small. If reconnection of the SRNS relocation method is performed only when the “predetermined condition” is satisfied, the processing load on the network side is not as great as previously concerned. Furthermore, in the situation where the “predetermined condition” is satisfied, the communication quality is considerably poor, so even if communication is not continuous at the moment of switching of the RNC, it is expected to be within the allowable range. Rather, switching the serving RNC to a more appropriate RNC is advantageous in that it can be expected to improve communication quality thereafter. In many cases, the “predetermined condition” is not satisfied in many cases, and the reconnection process in that case is performed by the subscriber line extension method. In this case, there is no need for handover if you are in a specified area, and handover is successful even if you are outside the specified area, so make sure to reconnect using the subscriber line extension method. Can do.

  In one aspect of the present invention, the reconnection processing by the subscriber line extension method and the SRNS relocation method is selectively used so as to be performed in a situation suitable for each method, so that when the wireless terminal requests reconnection after connecting to the RNC, The success rate of reconnection to the RNC or another RNC can be improved without excessively increasing the processing load on the network side.

  Examples of the present invention will be described below from the following viewpoints.

1. System configuration Radio network controller (RNC)
3. 3. Explanation of operation 3.1 Outline of operation 3.2 Subscriber line extension method 3.3 SRNS relocation method Effects of the embodiment

< 1. System configuration >
FIG. 1 shows a mobile communication system according to one embodiment. FIG. 1 shows a radio terminal 10, radio base stations (BTS) 20, 21, radio network control devices (RNC) 30, 31, and a network 1.

  The radio terminal 10 (UE) is a terminal having a radio communication function such as a mobile phone, and may be referred to as a mobile station (MS), a mobile terminal, a user apparatus (UE), or the like.

  The radio base stations 20 and 21 (BTS) form a radio link with the radio terminal 10. The radio base station performs radio communication with the radio terminal 10 in a predetermined area, and the predetermined area is referred to as a cell. In the figure, cells are indicated by 200 and 201.

  The radio network control devices 30 and 31 (RNC) are host devices that control one or more radio base stations and control communication of radio terminals. The RNC will be further described with reference to FIG.

  Network 1 (CN) generally represents the core network. Although not shown, the core network includes a circuit switching function unit (MSC / GMSC), a packet switching function unit (SGSN / GGSN), a home location register (HLR), a visitor location register (VRL), and the like.

  For convenience of explanation, only two cells and two RNCs are shown, but these numerical values are merely adopted for convenience of explanation, and any appropriate number may be used. In general, one or more RNCs are connected under the CN, and one or more BTSs are connected under the RNC.

< 2. Wireless network controller (RNC) >
FIG. 2 shows a radio network controller (RNC) according to one embodiment. This RNC may be used for RNC 30 and / or 31 of FIG. FIG. 2 shows a radio base station interface 301, an upper node interface 302, a signal processing unit 303 for the subscriber line extension method, a signal processing unit 304 for the SRNS relocation method, and a communication control unit 305.

  The radio base station interface 301 has a function of converting a signal and transmitting / receiving it in preparation for communication with one or more radio base stations (BTS) under the RNC.

  The upper node interface 302 has a function of converting a signal and transmitting / receiving in preparation for communication with a node, a functional element, or an entity in the core network (CN). The upper node interface 302 also has a function of converting a signal in preparation for communication with another RNC and transmitting / receiving (for example, communication between the RNCs 30 and 31).

The signal processing unit 303 for the subscriber line extension method performs processing for establishing a communication path by the subscriber line extension method under the control of the communication control unit 305. For example,
When the RNC is a serving RNC, the signal processing unit 303 for the subscriber line extension method is
・ Function to communicate with wireless terminals via subordinate wireless base stations,
-A function to create an instruction signal for instructing the setting of a wired line with the drift RNC and send it to the drift RNC; Have

When the RNC is a drift RNC, the signal processor 303 for the subscriber line extension method is
-A function that receives an instruction signal from the serving RNC and responds to the setting of the wired line; and-A function that relays a control signal between the serving RNC and the wireless terminal.

The SRNS relocation method signal processing unit 304 performs processing for establishing a communication path by the SRNS relocation method under the control of the communication control unit 305. For example, the signal processing unit 304 of the SRNS relocation method
A function of generating a relocation request signal indicating that the serving RNC for a certain wireless terminal should be switched and transmitting it to the core network (CN);
-In accordance with an instruction from the core network (CN), it has a function of serving as a serving RNC for a certain wireless terminal.

  The communication control unit 305 controls the operation of each element in the RNC. The communication control unit 305 performs control of calling / receiving from / to the wireless terminal (call control), handover control between cells, reconnection control, and the like. The communication control unit 305 also manages the state of the wireless terminal, and manages the cell with which the wireless terminal is communicating, the state of outgoing / incoming calls, the state at the time of reconnection, and the like. In particular, the communication control unit 305 analyzes the reconnection request signal from the wireless terminal and determines how to perform reconnection according to a predetermined determination criterion, as will be described in the following operation description.

< 3. Operation explanation >
Hereinafter, an operation example according to an embodiment of the present invention will be described. As an example, the radio terminal 10 establishes a radio connection with the radio access devices (RAN) (radio network control devices 30 and 31 and radio base stations 20 and 21) in the cells 200 and 201 by the IMT-2000 method. It can be communicated with. For convenience of explanation, it is assumed that the radio terminal 10 has established a radio connection of an individual channel within the cell 200. Thereafter, when the radio terminal 10 enters the area of the cell 201, a subscriber line extension method handover is performed. When the radio terminal 10 is located under the RNC 30, the subscriber line extension type handover is not performed. When a subscriber line extension type handover is performed, a communication path of control signals among the core network (CN) 1, the serving RNC 30, the drift RNC 31, the radio base station (BTS) 21, and the radio terminal 10 in the cell 201 Is established (see FIG. 5). For the user traffic signal, a communication path is established among the core network (CN) 1, the drift RNC 31, the radio base station (BTS) 21, and the radio terminal 10 in the cell 201.

< 3.1 Outline of operation >
FIG. 3 is a flowchart showing an operation example according to an embodiment of the present invention. In step S1, the serving RNC 30 receives the reconnection request signal from the radio terminal 10. The radio terminal 10 measures the radio propagation status regularly or irregularly (as necessary). When the radio propagation status becomes so bad that reconnection is required, the radio terminal 10 transmits a reconnection request signal to the serving RNC 30. The quality of the radio propagation status may be determined by the signal reception level, reception quality, etc. at the radio terminal 10. The event that causes the transmission of the reconnection request signal may occur not only in the radio propagation status but also in other conditions. In any case, when the reconnection request signal is transmitted from the radio terminal 10, the serving RNC 30 receives the reconnection request signal through the radio base station 20 or the drift RNC 31.

  In step S2, the serving RNC 30 analyzes the reconnection request signal. The serving RNC determines whether or not the destination terminal 10 that has transmitted the reconnection request signal is located in an area under the serving RNC 30. As the discrimination method, any appropriate method known in the art may be used. For example, when the first node receives a signal and transfers it to the second node, the first node transfers the signal with its own identification information (ID). In this case, if the reconnection request signal arrives from the radio base station 20, the ID of the radio base station 20 is attached to the reconnection request signal. If the reconnection request signal arrives from the drift RNC 31, the ID of the drift RNC 31 is attached to the reconnection request signal. The serving RNC 30 can determine the area where the wireless terminal 10 is located by checking the transfer source of the transferred reconnection request signal.

  If the wireless terminal 10 is located in a region other than the region under the serving RNC 30, the flow proceeds to step S3. Otherwise, that is, if the radio terminal 10 is located in an area under the serving RNC 30, the flow proceeds to step S4.

  In order to simplify the explanation, in step S2, it is determined whether or not the area where the unattended terminal 10 is located is an area under the serving RNC 30, but this is not essential. As described above, one switch has one or more RNCs, and another switch also has one or more other RNCs. In step S2, it may be determined whether or not the area where the unattended terminal 10 is located is an area under the control of a certain exchange. This is advantageous when the RNCs belonging to the same exchange can exchange control signals relatively quickly. More generally, it may be determined whether or not the area where the unattended terminal 10 is located is any predetermined area.

  In step S3, the serving RNC 30 determines whether or not the handover by the subscriber line extension method has failed. In the case of the current example, when reaching step S3, the wireless terminal 10 is located under the drift RNC 30. Therefore, if the communication state is good, handover by the subscriber line extension method should be performed. If the subscriber line extension type handover has not failed, the flow proceeds to step S4, and if it has failed, the flow proceeds to step S5.

  When the flow proceeds from step S3 to S5 in FIG. 3, the subscriber line extension type handover has failed. This means that the dedicated control channel has failed to establish a communication path between the RNC 30, 31, the BTS 21, and the UE 10. In this case, the reconnection request signal from the radio terminal (UE) 10 is transmitted not on the dedicated control channel but on the common control channel. When the communication path for the dedicated control channel is established, the reconnection request signal may be transmitted on the dedicated control channel or on the common channel.

  Whether or not the handover has failed may be determined based on any appropriate criterion. For example, when a subscriber line extension type handover is performed, the serving RNC instructs the drift RNC to that effect, and finally instructs the radio terminal to perform handover (if there is no risk of confusion, the instruction is May be referred to as a handover command). When the wireless terminal responds to this instruction, the control signal is exchanged through the communication path based on the subscriber line extension method (this response may also be referred to as a handover completion signal if there is no risk of confusion). . Therefore, the success or failure of the subscriber line extension type handover may be determined based on whether or not such a handover completion signal is received by the serving RNC 30. Alternatively, the success or failure of the subscriber line extension method handover may be determined based on whether or not the wired line between the serving RNC and the drift RNC is appropriately set. In step S3, the success or failure of the subscriber line extension type handover is determined as a typical example but is not essential. This is because it is an essential role of step S3 to determine whether or not to perform the SRNS relocation method when performing reconnection. For example, if the subscriber line extension method handover itself is successful, but the number of reconnection requests is relatively high or the communication quality is poor, the flow may proceed from step S3 to S5. .

< 3.2 Subscriber line extension method >
In step S4, reconnection is performed by the subscriber line extension method.

  FIG. 4 shows a general flowchart when reconnection is performed based on the subscriber line extension method. It is not essential that all steps of this flow are performed in step S4 of FIG. Some procedures may be omitted as necessary.

  In step S1, the serving RNC 30 receives a reconnection request signal from the radio terminal 10. This corresponds to step S1 in FIG.

  In step S2, the serving RNC 30 requests the drift RNC to set up a wired line between the serving RNC 30 and the drift RNC 31.

  In step S3, the serving RNC 30 requests the radio base station 21 to set up a wired line between the drift RNC 31 and a certain radio base station 21 under the drift RNC 31 (the drift RNC 31 relays such an instruction signal. .).

  In step S4, the radio base station 21 sets up a radio link with the radio terminal 10.

  In step S5, the radio terminal 10 transmits a response signal to the serving RNC 30. This response signal reaches the serving RNC 30 via the radio base station 21 and the drift RNC 31.

  In step S6, the serving RNC 30 transmits a reconnection instruction signal to the radio terminal 10. The reconnection instruction signal reaches the radio terminal 10 via the drift RNC 31 and the radio base station 21.

  In step S7, the wireless terminal 10 performs reconnection according to the reconnection instruction signal. As a result, synchronization between the radio terminal 10 and the serving RNC 30 is maintained, and thereafter, control signals are exchanged between them.

  If it is clear that the wired line in steps S2 and S3 and the wireless link in step S4 have been established, these processes may be omitted.

  FIG. 5 schematically shows how the communication path is established by the subscriber line extension method as described above.

  The above description mainly assumes the case from step S3 to step S4 in FIG. In the case of going from step S2 in FIG. 3 to step S4, the wireless terminal 10 is located under the serving RNC 30. Accordingly, the radio terminal 10 exchanges control signals with the serving RNC 30 via a certain radio base station 20. The reconnection in this case may be performed as described above as follows.

  First, instead of step S3 in FIG. 4, the serving RNC 30 requests the radio base station 20 to set up a wired line between the serving RNC 30 and a certain radio base station 20 under its control.

  Instead of step S4, the radio base station 20 sets up a radio link with the radio terminal 10.

  Instead of step S5, the radio terminal 10 transmits a response signal to the serving RNC 30. This response signal reaches the serving RNC 30 via the radio base station 20.

  Instead of step S6, the serving RNC 30 transmits a reconnection instruction signal to the radio terminal 10. The reconnection instruction signal reaches the radio terminal 10 via the radio base station 20.

  Instead of step S7, the wireless terminal 10 performs reconnection according to the reconnection instruction signal. As a result, synchronization between the radio terminal 10 and the serving RNC 30 is maintained, and thereafter, control signals are exchanged between them.

< 3.3 SRNS relocation method >
In step S5 in FIG. 3, reconnection is performed by the SRNS relocation method.

  FIG. 6 shows a general flowchart when reconnection is performed based on the SRNS relocation method. Similar to the float of FIG. 4, it is not essential that all steps of this flow are performed in step S5 of FIG. Some procedures may be omitted as necessary.

  In step S1 of FIG. 6, the RNC 30 before switching receives a reconnection request signal from the radio terminal 10. This also corresponds to step S1 in FIG. However, this reconnection request signal is typically transmitted as a common control channel. Generally, when the communication path for the dedicated control channel has not been established, the control information is transmitted on the common control channel.

  In step S2, the RNC 30 before switching transmits a relocation request signal to the core network (CN) 1. This relocation request signal indicates that the RNC that controls communication of the wireless terminal should be switched from the RNC 30 to the RNC 31. Specifically, the core network 1 is an exchange having a function of controlling switching of the RNC or a control node higher than the RNC.

  In step S3, the core network (CN) 1 transmits a relocation instruction signal to the RNC 31. This relocation instruction signal also essentially indicates that the RNC that controls the communication of the wireless terminal should be switched from the RNC 30 to the RNC 31. In practice, a number of processing procedures are executed between the core network (CN) 1 and the RNCs 30 and 31, but these are omitted for the sake of simplicity of explanation.

  In step S4, the serving RNC 31 requests the radio base station 21 to set up a wired line between the RNC 31 and a certain radio base station 21 under the RNC 31.

  In step S5, the radio base station 21 sets up a radio link with the radio terminal 10.

  In step S6, the wireless terminal transmits a response signal to the switched RNC 31. The response signal reaches the switched RNC 31 via the radio base station 21.

  In step S7, the switched RNC 30 transmits a reconnection instruction signal to the radio terminal 10. The reconnection instruction signal reaches the radio terminal 10 via the radio base station 21.

  In step S8, the wireless terminal 10 performs reconnection according to the reconnection instruction signal. As a result, synchronization between the radio terminal 10 and the serving RNC 31 is maintained, and thereafter, control signals are exchanged between them. The old communication path via the RNC 30 before switching is released at an appropriate time.

  FIG. 7 shows a state after the serving RNC is switched by the SRNS relocation method.

  In general, the wireless terminal communicates on an individual channel before and after switching of the RNC. However, if the wireless terminal communicates on the dedicated channel before switching the RNC by the SRNS relocation method, it is not essential for the wireless terminal to communicate on the dedicated channel after switching the RNC. The wireless terminal may communicate on the common channel after switching the RNC.

< 4. Effects of Examples >
According to this embodiment, (1) when the wireless terminal is located in a predetermined area (for example, the area under the serving RNC, the area under the exchange to which the serving RNC belongs), and (2) the wireless terminal Even if you are located in a region other than the specified region, if it is not the situation to switch the serving RNC (typically, if the subscriber line extension method handover itself was successful), the reconnection is This is done by the subscriber line extension method. These situations are expected to occur relatively often when reconnection is required. In these situations where there is no need to switch the serving RNC, it is expected that the wireless terminal is not moving so fast. Therefore, reconnection can be reliably performed by performing the subscriber line extension method in which communication is not easily interrupted.

  However, in this embodiment, when the wireless terminal is in a region other than a predetermined region and the serving RNC should be switched (typically, the subscriber line extension type handover has failed). ), The reconnection is done with the SRNS relocation method. It is expected that the number of times such a situation will occur is relatively small. Therefore, even if the SRNS relocation method is performed, the burden on the network side does not increase excessively. Also, in a situation where the subscriber line extension type handover has failed, it is desirable that the communication is performed satisfactorily even if the communication is instantaneously discontinuous. If reconnection by the SRNS relocation method is performed only in such a situation, any of the matters that are concerned as a demerit of the SRNS relocation method will not stand out. Rather, after the RNC is switched, communication is performed with a more appropriate serving RNC, so the advantages of the SRNS relocation method are greatly demonstrated. Therefore, in this case also, reconnection can be performed reliably.

  The present invention may be applied to any appropriate mobile communication system using the subscriber line extension scheme and the SRNS relocation scheme. For example, the present invention may be used with HSDPA / HSUPA W-CDMA systems, LTE systems, IMT-Advanced systems, WiMAX systems, Wi-Fi systems, and the like.

  Although the present invention has been described with reference to particular embodiments, they are merely exemplary and those skilled in the art will appreciate various variations, modifications, alternatives, substitutions, and the like. Although specific numerical examples have been described in order to facilitate understanding of the invention, these numerical values are merely examples and any appropriate values may be used unless otherwise specified. The division of the embodiment or item is not essential to the present invention, and the matters described in two or more embodiments or items may be used in combination as necessary, or may be described in a certain embodiment or item. Matters may apply to matters described in other examples or items (unless they conflict). For convenience of explanation, an apparatus according to an embodiment of the present invention has been described using a functional block diagram, but such an apparatus may be realized by hardware, software, or a combination thereof. The present invention is not limited to the above embodiments, and various modifications, modifications, alternatives, substitutions, and the like are included in the present invention without departing from the spirit of the present invention.

It is a figure which shows the mobile communication system by one Example. 1 is a diagram illustrating a radio network controller (RNC) according to one embodiment. FIG. It is a flowchart which shows the process example of the reconnection by one Example. It is a flowchart which shows the process example of the reconnection by a subscriber line extension system. It is a figure which shows typically a mode that the communication path was established by the subscriber line extension system. It is a flowchart which shows the example of a process of the reconnection by a SRNS relocation system. It is a figure which shows typically a mode that the communication path was switched by the SRNS relocation system.

Explanation of symbols

1 Network 10 Wireless terminal 20, 21 Wireless base station (BTS)
30, 31 Radio Network Controller (RNC)
200, 201 Cell 301 Radio base station interface 302 Upper node interface 303 Signal processing unit for subscriber line extension method 304 Signal processing unit for SRNS relocation method 305 Communication control unit

Claims (6)

A radio network controller connected to one or more radio base stations and a core network,
A communication control unit for controlling communication of the wireless terminal;
Subscription to receive signals from and transmit signals to the other radio network control devices so that signals are transmitted to and received from the radio terminals via the other radio network control devices The person line extension processing department,
And the reconnection request signal transmitted from the wireless terminal is received via the other wireless network control device, the wireless network control device, the other wireless network control device, and the If the communication control unit has not confirmed that a communication path has been established between wireless terminals,
A radio network control apparatus configured to notify the core network that control of communication of the radio terminal is to be performed by the other radio network control apparatus. The radio network controller according to claim 1, wherein when it is confirmed that the communication path is established, the subscriber line extension processing unit transmits a signal permitting reconnection. The wireless network control device according to claim 1, wherein the other wireless network control device belongs to an exchange different from the exchange to which the wireless network control device belongs. The radio network controller according to claim 1, wherein the reconnection request signal is transmitted as a common control channel, and an individual control channel is transmitted in the communication path. A mobile communication system including at least one radio base station and a radio network control device connected to a core network, and at least one other radio base station and another radio network control device connected to the core network The wireless network control device comprises:
A communication control unit for controlling communication of the wireless terminal;
Subscription to receive signals from and transmit signals to the other radio network control devices so that signals are transmitted to and received from the radio terminals via the other radio network control devices The person line extension processing department,
And the reconnection request signal transmitted from the wireless terminal is received via the other wireless network control device, the wireless network control device, the other wireless network control device, and the If the communication control unit has not confirmed that a communication path has been established between wireless terminals,
A mobile communication system in which the core network is notified that control of communication of the wireless terminal is to be performed by the other wireless network control device. A mobile communication system including at least one radio base station and a radio network control device connected to a core network, and at least one other radio base station and another radio network control device connected to the core network A method used in
The wireless network control device receiving a reconnection request signal transmitted from a wireless terminal from a wireless base station or the other wireless network control device;
When the reconnection request signal transmitted from the wireless terminal is received via the other wireless network control device, communication is performed between the wireless network control device, the other wireless network control device, and the wireless terminal. The radio network controller determining whether a path is established; and
If it is not confirmed that the communication path is established, the radio network controller notifies the core network that the communication control of the radio terminal should be performed by the other radio network controller. And steps to
Having a method.

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