JP4785999B2 - Mobile communication method and switching center - Google Patents

Description

  The present invention relates to a mobile communication method and a switching center.

  In an LTE (Long Term Evolution) mobile communication system, an exchange MME (Mobility Management Entity) is configured to perform access control (Access Control) for a handover destination cell of a mobile station UE in a handover procedure.

3GPP TS 36.300 (V9.1.0), “Evolved Universal Terrestrial Radio Access (E-UTRA) and Evolved Universal Terrestrial Radio Network 9 H 3GPP TS36.413 (V9.0.0), “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 application protocol (X2AP)”, September 2009 3GPP TS36.423 (V9.0.0), “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 application protocol (X2AP)”, September 2009

  However, in such a mobile communication system, when the “CSG (Closed Subscriber Group) ID” of the handover destination cell and the “CSG ID” of the handover source cell are different, access control by the above-mentioned switching center MME is required, so X2 S1 handover must be performed instead of handover.

  Further, even when the “CSG ID” of the handover destination cell and the “CSG ID” of the handover source cell are the same, as shown in FIG. 9, the mobile station UE accesses between the mobile station UE and the network. If the information related to the expiration date of the “CSG ID” of a possible cell is not immediately synchronized and does not match, access control by the switching center MME described above is still necessary, so it is not an X2 handover, S1 handover must be performed.

  For example, after the period in which the mobile station UE can access the cell of “CSG ID = # 20” expires, the network deletes information related to “CSG ID = # 20”, while the mobile station UE When the information related to “ID = # 20” has not been deleted, the information related to “CSG ID” of the cell accessible by the mobile station UE does not match between the mobile station UE and the network. Become.

  When X2 handover is performed in this state, there is a problem in that access to the cell of “CSG ID = # 20” of the mobile station UE cannot be denied.

  Therefore, the present invention has been made in view of the above-described problems, and is capable of performing X2 handover regardless of whether or not the period during which the mobile station UE can access the CSG cell has expired. An object is to provide a communication method and an exchange.

  A first feature of the present invention is a mobile communication method for performing a handover procedure from a first cell under a first radio base station of a mobile station to a second cell under a second radio base station. After the connection destination cell is switched from the first cell to the second cell, the second radio base station uses a path switching request signal for requesting switching of a path in the downlink to the switching station. The step A of notifying the subscriber group ID to which the second cell belongs and the access mode in which the second cell is operating, and the switching center based on the notified subscriber group ID and the access mode, And a step B of performing access control on the second cell of the mobile station.

  According to a second aspect of the present invention, there is provided an exchange station, wherein the second radio base station in a handover procedure from a first cell under the first radio base station of the mobile station to a second cell under the second radio base station. A receiver configured to receive a path switching request signal for requesting switching of a path in the downlink from a station, and the second cell included in the path switching request signal in the handover procedure And a determination unit configured to perform access control on the second cell of the mobile station based on a subscriber group ID and an access mode in which the second cell is operating. .

  As described above, according to the present invention, there is provided a mobile communication method and an exchange that can perform X2 handover regardless of whether or not the period during which the mobile station UE can access the CSG cell has expired. Can be provided.

1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. It is a functional block diagram of the exchange MME which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the information element of "Path Switch Request" transmitted with the mobile communication system which concerns on the 1st Embodiment of this invention. It is a figure which shows an example of the information element of "Path Switch Request Acknowledge" transmitted with the mobile communication system which concerns on the 1st Embodiment of this invention. FIG. 2 is a functional block diagram of a radio base station HeNB according to the first embodiment of the present invention. It is a figure which shows an example of the information element of "Handover Request" transmitted with the mobile communication system which concerns on the 1st Embodiment of this invention. FIG. 3 is a sequence diagram showing an operation of the mobile communication system according to the first embodiment of the present invention. It is a flowchart which shows operation | movement of the exchange MME which concerns on the 1st Embodiment of this invention. It is a figure for demonstrating the problem of the conventional mobile communication system.

(Configuration of mobile communication system according to the first embodiment of the present invention)
With reference to FIG. 1 thru | or FIG. 6, the structure of the mobile communication system which concerns on the 1st Embodiment of this invention is demonstrated.

  The mobile communication system according to the present embodiment is an LTE mobile communication system, and as illustrated in FIG. 1, an exchange MME, a radio base station HeNB (Home-eNB) # 1 / HeNB # 2, and a mobile And a station UE.

  In the mobile communication system according to the present embodiment, the CSG cell # 1 is provided under the radio base station HeNB # 1, and the CSG cell # 2 is provided under the radio base station HeNB # 2.

  The “CSG ID” of CSG cell # 1 and the “CSG ID” of CSG cell # 2 may be different or the same.

  Further, the radio base station HeNB # 1 and the radio base station HeNB # 2 are connected by an X2 interface, and the radio base station HeNB # 1 and the exchange MME are connected by an S1 interface, and the radio base station HeNB # 2 and the switching center MME are connected by an S1 interface.

  As illustrated in FIG. 2, the exchange MME includes a reception unit 11, a storage unit 12, a determination unit 13, and a transmission unit 14.

  The receiving unit 11 is configured to receive a signal such as “Path Switch Request” from the radio base station HeNB that manages the handover destination cell in the handover procedure of the mobile station UE.

  FIG. 3 shows an example of an information element of “Path Switch Request” transmitted by the radio base station HeNB that manages the handover destination cell.

  As shown in FIG. 3, in “Path Switch Request”, “CSG ID” of the handover destination cell, “Cell Access Mode”, and the like can be set as information elements.

  Here, “Cell Access Mode” is an information element indicating the access mode in which the handover destination cell is operating. Specifically, whether the access mode in which the handover destination cell is operating is “hybrid mode”. 1-bit information indicating whether or not.

  When the access mode in which the handover destination cell is operating is the “open mode”, the “CSG ID” and the “Cell Access Mode” of the handover destination cell are not set in “Path Switch Request”.

  The storage unit 12 is configured to store “UE subscription info” related to each mobile station UE.

  The “UE subscription info” includes “Allowed CSG ID” indicating “CSG ID” of a cell accessible by the mobile station UE. The “Allowed CSG ID” may have a valid period.

  In the handover procedure of the mobile station UE, the determination unit 13 is based on the “CSG ID” to which the handover destination cell included in the “Path Switch Request” received by the reception unit 11 belongs and the access mode in which the handover cell is operating. The mobile station UE is configured to perform access control on the handover cell.

  In the handover procedure of the mobile station UE, the transmission unit 14 performs “Path Switch Request Acknowledge” or “Path Switch Request Failure” on the radio base station HeNB managing the handover destination cell according to the determination result by the determination unit 13. Is configured to send.

  FIG. 4 illustrates an example of an information element of “Path Switch Request Acknowledge” transmitted by the transmission unit 14.

  As shown in FIG. 4, “Path Switch Request Acknowledge” can set “CSG membership status” or the like as an information element.

  Here, “CSG membership status” is information indicating whether or not the mobile station UE is a registered mobile station in the handover destination cell.

  For example, when the mobile station UE is a registered mobile station in the handover destination cell, “member” is set as “CSG membership status”, and when the mobile station UE is an unregistered mobile station in the handover destination cell, “CSG “non member” is set as “membership status”.

  When the access mode in which the handover destination cell is operating is “open mode” or “closed mode”, “CSG membership status” is not set in “Path Switch Request Acknowledge”.

  Specifically, when the determination unit 13 determines that the mobile station UE can access the handover destination cell based on the “CSG ID” included in the “Path Switch Request”, and When it is determined that the access mode in which the handover destination cell is operating is the “hybrid mode”, the transmission unit 14 sets “CSG membership status = member” to the radio base station HeNB that manages the handover destination cell. It is configured to transmit a “Path Switch Request Acknowledge”.

  Further, when the determination unit 13 determines that the mobile station UE can access the handover destination cell based on the “CSG ID” included in the “Path Switch Request”, and the handover destination cell When it is determined that the access mode in which is operating is “closed mode”, “Path Switch Request Acknowledge” is transmitted to the radio base station HeNB managing the handover destination cell.

  In this “Path Switch Request Acknowledge”, “CSG membership status” is not set.

  Furthermore, when the determination unit 13 determines that the mobile station UE cannot access the handover destination cell based on the “CSG ID” included in the “Path Switch Request”, and the handover destination cell is When it is determined that the operating access mode is “hybrid mode”, “Path Switch Request Acknowledge” including “CSG membership status = non member” is sent to the radio base station HeNB that manages the handover destination cell. Configured to send.

  In addition, when the determination unit 13 determines that the mobile station UE is not accessible to the handover destination cell based on the “CSG ID” included in the “Path Switch Request”, and the handover destination cell is When it is determined that the operating access mode is “closed mode”, “Path Switch Request Fail” is transmitted to the radio base station HeNB that manages the handover destination cell.

  As illustrated in FIG. 5, the radio base station HeNB includes a reception unit 21, a storage unit 22, a determination unit 23, and a transmission unit 24.

  The receiving unit 21 is configured to receive a signal such as “Measurement Report” from the mobile station UE.

  In addition, in the handover procedure of the mobile station UE, when the radio base station HeNB is a radio base station that manages the handover destination cell, the receiving unit 21 receives “Synchronization” or “RRC Connection Reconfiguration Complete” from the mobile station UE. Are received.

  Further, in the handover procedure of the mobile station UE, when the radio base station HeNB is a radio base station that manages the handover destination cell, the receiving unit 21 receives “Path Switch Request Acknowledge” or “Path Switch” from the exchange MME. It is configured to receive a signal such as “Request Faille” or a signal such as “Handover Request” or “SN Status Transfer” from a radio base station that manages the handover source cell.

  Further, in the handover procedure of the mobile station UE, when the radio base station HeNB is a radio base station that manages the handover source cell, the reception unit 21 receives “Handover Request Ack” from the radio base station that manages the handover destination cell. ”Or“ UE Context Release ”or the like.

  The storage unit 22 is configured to store a “CSG ID” of a subordinate cell and an access mode in which the subordinate cell is operating.

  In addition, the storage unit 22 uses the NRT (Neighbor Release Table) to operate the “CSG ID” of the cell managed by the adjacent radio base station or the cell managed by the adjacent radio base station. The access mode is configured to be stored.

  In the handover procedure of the mobile station UE, the determination unit 23 compares the “CSG ID” included in the “Measurement Report” received from the mobile station UE and the “CSG ID” of the subordinate cell managed by the storage unit 22. By doing so, it may be configured to determine whether the “CSG ID” of the handover destination cell matches the “CSG ID” of the handover source cell.

  Here, the determination unit 23 may be configured to determine that the X2 handover is performed when it is determined that they are the same, and to determine that the S1 handover is performed when it is determined that they are not the same. .

  In addition, the determination unit 23 performs the “CSG ID” included in the “Measurement Report” received from the mobile station UE and the “CSG ID” of the cell included in the NRT managed by the storage unit 22 in the handover procedure of the mobile station UE. The “CSG ID” included in the “Measurement Report” received from the mobile station UE may be determined to determine whether or not the “CSG ID” is correct.

  In addition, the determination unit 23 determines whether the handover destination cell is operating based on “PCI (Physical Cell ID)” included in “Measurement Report” received from the mobile station UE in the handover procedure of the mobile station UE. The above determination may be performed only when the access mode is “hybrid mode” or “closed mode”.

  The transmission unit 24 is configured to transmit a signal such as “Measurement Control” to the mobile station UE.

  Further, in the handover procedure of the mobile station UE, when the radio base station HeNB is a radio base station that manages the handover destination cell, the transmission unit 24 transmits “RRC Connection” including “mobility Control information” to the mobile station UE. It is configured to transmit a signal such as “Reconfiguration”.

  Also, in the handover procedure of the mobile station UE, when the radio base station HeNB is a radio base station that manages the handover source cell, the transmission unit 24 sends “Handover” to the radio base station that manages the handover destination cell. It is configured to transmit a signal such as “Request” or “SN Status Transfer”.

  FIG. 6 shows an example of an information element of “Handover Request” transmitted by the transmission unit 24.

  As shown in FIG. 6, “Target CSG ID”, “Preliminary access check”, and the like can be set as information elements in “Handover Request”.

  Here, “Target CSG ID” indicates “CSG ID” of the handover destination cell, and “Preliminary access check” is information indicating whether or not the mobile station UE can access the handover destination cell. In addition, in the “Preliminary access check”, the value of the “Preliminary access check” notified from the mobile station UE is set.

  Note that the transmission unit 24 may be configured to set “Target CSG ID” in “Handover Request” only when the mobile station UE can access the handover destination cell.

  The transmission unit 24 may be configured to set “Preliminary access check” to “Handover Request” only when the access mode in which the handover destination cell is operating is the “hybrid” mode.

  Further, when the determination unit 23 determines that the “CSG ID” included in the “Measurement Report” received from the mobile station UE is correct, the transmission unit 24 does not set the “Target CSG ID” in the “Handover Request”. It may be configured as follows.

  Furthermore, in the handover procedure of the mobile station UE, when the radio base station HeNB is a radio base station that manages the handover destination cell, the transmission unit 24 sends “Handover” to the radio base station that manages the handover source cell. It is configured to transmit a signal such as “Request Ack” or “UE Context Release”.

(Operation of the mobile communication system according to the first embodiment of the present invention)
With reference to FIG.7 and FIG.8, operation | movement of the mobile communication system which concerns on the 1st Embodiment of this invention is demonstrated.

  As shown in FIG. 7, in step S0, access restriction information related to roaming of the mobile station UE is stored in the CSG cell # 1 under the radio base station HeNB # 1.

  In Step S1, the radio base station HeNB # 1 transmits “Measurement Control” to the mobile station UE communicating with the CSG cell 1.

  In step S2, the mobile station UE transmits “Measurement Report” using the radio resource allocated by the radio base station HeNB # 1 at a predetermined timing.

  In step S3, the radio base station HeNB # 1 determines to start a handover procedure from the CSG cell # 1 of the mobile station UE to the CSG cell # 2 under the radio base station HeNB # 2.

  Here, the radio base station HeNB # 1 may perform the determination by the determination unit 23 described above. In the example of FIG. 7, the “CSG ID” of the CSG cell # 1 and the “CSG ID” of the CSG cell # 2 are the same, and are both “# 20”.

  In step S4, the radio base station HeNB # 1 gives “Target CSG ID” and “Preliminary access check” in which “CSG ID = # 20” of the CSG cell # 2 is set to the radio base station HeNB # 2. Including “Handover Request” is transmitted.

  In step S5, the radio base station HeNB # 2 performs admission control on the “Handover Request”, and in step S6, transmits the “Handover Request Ack” to the radio base station HeNB # 1.

  In Step S7, the radio base station HeNB # 1 transmits “RRC Connection Reconfiguration” including “mobility Control information” to the mobile station UE.

  After the switching process from the CSG cell # 1 to the CSG cell # 2 of the connection destination cell of the mobile station UE is completed, in step S8, the radio base station HeNB # 1 transmits “SN” to the radio base station HeNB # 2. Send "Status Transfer".

  After the unsent packets to the mobile station UE accumulated in the radio base station HeNB # 1 are transferred to the radio base station HeNB # 2 and buffered, in step S9, the mobile station UE 2 performs a radio link synchronization process and transmits Random Access Preamble.

  In step S10, the radio base station HeNB # 2 transmits “TA (Timing Adjustment)” to the mobile station UE. In step S11, the mobile station UE transmits “TA (Timing Adjustment)” to the radio base station HeNB # 2. RRC Connection Reconfiguration Complete ”is transmitted.

  In step S12, the radio base station HeNB # 2 transmits “Path Switch Request” including “CSG ID” and “Cell access mode” related to the CSG cell # 2 to the switching center MME.

  The switching center MME performs access control for the CSG cell # 2 of the mobile station UE in accordance with the received “Path Switch Request”. Such access control will be described later with reference to FIG.

  In step S13, when the above-described access control is successful, the switching center MME transmits “User Plane update request” to the gateway device S-GW (Serving Gateway).

  The gateway device S-GW performs downlink switching processing for the mobile station UE in step S14, and transmits “User Plane update response” to the switching center MME in step S15.

  In step S16, the switching center MME transmits “Path Switch Request Acknowledge” including “CSG membership status” to the radio base station HeNB # 2.

  In step 17, the radio base station HeNB # 2 transmits “UE Context Release” to the radio base station HeNB # 1, and in step S18, the radio base station HeNB # 1 performs UE context related to the mobile station UE. Delete information.

  Hereinafter, with reference to FIG. 8, the access control in the above-described exchange MME and the operation in step S15 will be described.

  As shown in FIG. 8, in step S101, the switching center MME determines that the mobile station UE is based on “CSG ID # 20” included in the received “Path Switch Request” and “Allowed CSG ID” of the mobile station UE. It is determined whether or not the CSG cell # 2 (handover destination cell) with “CSG ID = # 20” is accessible.

  If it is determined that access is possible, the operation proceeds to step S105. If it is determined that access is not possible, the operation proceeds to step S102.

  In step S102, the switching center MME determines that the access mode in which the CSG cell # 2 is operating is “hybrid mode” based on the “CSG ID” and the “Cell access mode” included in the received “Path Switch Request”. It is determined whether or not there is.

  If it is determined that the mode is “hybrid mode”, the operation proceeds to step S103. If it is determined that the mode is not “hybrid mode”, the operation proceeds to step S104.

  In step S103, the switching center MME transmits “Path Switch Request Acknowledge” including “CSG membership status = non member” to the radio base station HeNB # 2.

  In step S104, the switching center MME transmits “Path Switch Request Failure” indicating that the handover procedure of the mobile station UE to the CSG cell # 2 has failed to the radio base station HeNB # 2.

  In step S105, the switching center MME determines whether or not the “Cell access mode” included in the received “Path Switch Request” indicates “hybrid mode”.

  When it is determined that the “hybrid mode” is indicated, this operation proceeds to step S106, and when it is determined that the “hybrid mode” is indicated (that is, the “closed mode”), this operation is performed. Advances to step S107.

  In step S106, the switching center MME transmits “Path Switch Request Acknowledge” including “CSG membership status = member” to the radio base station HeNB # 2.

  In step S107, the switching center MME transmits “Path Switch Request Acknowledge” that does not include “CSG membership status = member” to the radio base station HeNB # 2.

(Operations and effects of the mobile communication system according to the first embodiment of the present invention)
According to the mobile communication system according to the first embodiment of the present invention, the radio base station HeNB that manages the handover destination cell sends the “CSG ID” of the handover destination cell to the switching center MME by “Path Switch Request”. ”And the access mode in which the handover destination cell is operating, the switching center MME can perform access control on the handover destination cell of the mobile station UE even in the X2 handover procedure.

  As a result, X2 handover can be performed regardless of whether or not the period during which the mobile station UE can access the handover destination cell # 2 has expired.

  The characteristics of the present embodiment described above may be expressed as follows.

  The first feature of the present embodiment is that the CSG cell # 1 (first cell) subordinate to the radio base station HeNB # 1 (first radio base station) of the mobile station UE to the radio base station HeNB # 2 (second radio base). Station) is a mobile communication method for performing a handover procedure to a subordinate CSG cell # 2 (second cell), and after the connection destination cell of the mobile station UE is switched from CSG cell # 1 to CSG cell # 2, The base station HeNB # 2 transmits “Path Switch Request (path switching request signal for requesting path switching in the downlink)” to the switching center MME to “CSG ID (subscriber) to which the CSG cell # 2 belongs. (Group ID) = # 20 ”and the process A for notifying the access mode (hybrid mode / closed mode) in which the CSG cell # 2 is operating, and the exchange MME The present invention includes a step B of performing access control on the CSG cell # 2 of the mobile station UE based on the known “CSG ID = # 20” and the access mode in which the CSG cell # 2 is operating.

  In the first feature of the present embodiment, in step B, the switching center MME determines that the mobile station UE can access the CSG cell # 2 based on the notified “CSG ID = # 20”. If it is determined that the notified access mode is the “hybrid mode”, the radio base station HeNB # 2 is notified of “CSG membership status = member (the mobile station UE is registered in the CSG cell # 2). “Path Switch Request Acknowledge (path switching success signal)” including “information indicating that the mobile station is a mobile station” may be transmitted.

  In the first feature of the present embodiment, in step B, the switching center MME determines that the mobile station UE can access the CSG cell # 2 based on the notified “CSG ID = # 20”. If it is determined that the notified access mode is the “closed mode”, “Path Switch Request Acknowledge” may be transmitted to the radio base station HeNB # 2.

  In the first feature of the present embodiment, in step B, the switching center MME determines that the mobile station UE is not accessible to the CSG cell # 2 based on the notified “CSG ID = # 20”. If it is determined that the notified access mode is the “hybrid mode”, the radio base station HeNB # 2 is notified of “CSG membership status = non member (the mobile station UE is not in the CSG cell # 2). “Path Switch Request Acknowledge” including “information indicating that the mobile station is a registered mobile station” may be transmitted.

  In the first feature of the present embodiment, in step B, the switching center MME determines that the mobile station UE is not accessible to the CSG cell # 2 based on the notified “CSG ID = # 20”. If it is determined that the notified access mode is “closed mode”, a “Path Switch Request Failure (path switching failure signal)” may be transmitted to the radio base station HeNB # 2. .

  A second feature of the present embodiment is an exchange MME, which is a handover procedure from the CSG cell # 1 under the radio base station HeNB # 1 of the mobile station UE to the CSG cell # 2 under the radio base station HeNB # 2. , The receiving unit 11 configured to receive “Path Switch Request” from the radio base station HeNB # 2, and “CSG ID = CSG cell # 2 included in“ Path Switch Request ”in the handover procedure belongs to“ CSG ID = And # 20 ”and a determination unit 13 configured to perform access control on the CSG cell # 2 of the mobile station UE based on the access mode in which the CSG cell # 2 operates. .

  In the second feature of the present embodiment, when the determination unit 13 determines that the mobile station UE is accessible to the CSG cell # 2 based on “CSG ID = # 20”, and CSG When it is determined that the access mode in which the cell # 2 is operating is the “hybrid mode”, the “Path Switch Request Acknowledge” including “CSG membership status = member” is transmitted to the radio base station HeNB # 2. You may comprise the transmission part 14 comprised so that.

  In the second feature of the present embodiment, when the determination unit 13 determines that the mobile station UE is accessible to the CSG cell # 2 based on “CSG ID = # 20”, and CSG Transmitter configured to transmit “Path Switch Request Acknowledge” to the radio base station HeNB # 2 when it is determined that the access mode in which the cell # 2 is operating is “closed mode” 14 may be included.

  In the second feature of the present embodiment, the determination unit 13 determines that the mobile station UE is not accessible to the CSG cell # 2 based on “CSG ID = # 20”, and the CSG cell. When it is determined that the access mode in which # 2 is operating is the “hybrid mode”, “Path Switch Request Acknowledge” including “CSG membership status = non member” is transmitted to the radio base station HeNB # 2. You may comprise the transmission part 14 comprised so that.

  In the second feature of the present embodiment, the determination unit 13 determines that the mobile station UE is not accessible to the CSG cell # 2 based on “CSG ID = # 20”, and the CSG cell. When it is determined that the access mode in which # 2 is operating is the “closed mode”, the transmission unit 14 configured to transmit “Path Switch Request Fail” to the radio base station HeNB # 2 You may have.

  The operations of the exchange MME, the radio base station HeNB, and the mobile station UE described above may be performed by hardware, may be performed by a software module executed by a processor, or may be performed by a combination of both. May be.

  The software module includes a RAM (Random Access Memory), a flash memory, a ROM (Read Only Memory), an EPROM (Erasable Programmable ROM), an EEPROM (Electronically Erasable and Programmable ROM, a hard disk, a registerable ROM, a hard disk). Alternatively, it may be provided in a storage medium of an arbitrary format such as a CD-ROM.

  Such a storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, such a storage medium may be integrated in the processor. Such a storage medium and processor may be provided in the ASIC. Such an ASIC may be provided in the exchange MME, the radio base station HeNB, or the mobile station UE. Further, the storage medium and the processor may be provided in the exchange MME, the radio base station HeNB, and the mobile station UE as discrete components.

  Although the present invention has been described in detail using the above-described embodiments, it is obvious to those skilled in the art that the present invention is not limited to the embodiments described in this specification. The present invention can be implemented as modified and changed modes without departing from the spirit and scope of the present invention defined by the description of the scope of claims. Therefore, the description of the present specification is for illustrative purposes and does not have any limiting meaning to the present invention.

MME: switching station HeNB: radio base station 11, 21: receiving unit 12, 22 ... storage unit 13, 23 ... determining unit 14, 24 ... transmitting unit

Claims (1)

  A radio base station used in a mobile communication method for performing a handover procedure from a first cell to a second cell of a mobile station,
  A determination unit configured to determine to perform an X2 handover when it is determined that the subscriber group ID of the first cell matches the subscriber group ID of the second cell; Wireless base station.