JP2009284507A - Mobile station, mobile switching center, and mobile communication method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mobile station, mobile center, and mobile communication method in which a mobile station automatically retries a call procedure when a selected cell does not have setting information "UE Context". <P>SOLUTION: This mobile station 100 includes: a cell selecting unit 106 for retrying a cell selection process for a predetermined time period after the mobile station fails to detect a radio link formed between the mobile station and a first wireless base station for controlling a first cell; a connection retry request signal transmission unit 102 for transmitting a connection retry request signal to a second radio base station for controlling a second cell when a selected second cell is determined to be a cell using the same radio access system as the first cell; and a call retry procedure start unit 116 for starting a call retry procedure to a mobile switching center for controlling the second radio base station when a response signal received from the second radio base station with respect to a connection retry request signal is determined to reject reconnection, or when the second cell is determined to be a cell using a different radio access system from the first cell. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a mobile communication method, a mobile station, and a mobile switching center that perform communication between a mobile station and a mobile switching center via a radio base station.

  In a mobile communication system considered as “Evolved universal terrestrial radio access network (E-UTRAN)”, when a mobile station is communicating with a predetermined cell, the mobile base station manages the predetermined cell. If a cell satisfying the required quality is reselected (Cell Reselection) within a predetermined period after the detection of the radio link between the two and the radio base station fails (Radio Link Failure), the radio base station that manages the reselected cell Is configured to transmit a reconnection request signal (see Non-Patent Document 1).

3GPP 36.300 V8.3.0 Technical specification group radio access network; Evolved universal terrestrial radio access (E-UTRA) and Evolved universal terrestrial radio access network (E-UTRAN); Overall description; Stage 2,10.1.6

  However, the above-described mobile communication system has the following problems.

  As described above, if the radio base station that has received the reconnection request signal transmitted by the mobile station holds the setting information (UE Context) related to the mobile station, according to the reconnection request signal, When the communication by the mobile station is continued, but the setting information (UE Context) related to the mobile station is not held, the reconnection request signal is rejected.

  In addition, after the above-mentioned “Radio Link Failure” has occurred, it has been determined that the cells reselected within a certain period are only cells (Inter-RAT cells) that use a radio access scheme different from the above-mentioned predetermined cells. In this case, since the setting information (UE Context) related to the mobile station is not held in the “Inter-RAT cell”, the mobile station deletes the setting information (UE Context) related to the mobile station. It is configured.

  Therefore, as described above, when a mobile station transmits a reconnection request signal to a radio base station that does not hold the setting information (UE Context) related to the mobile station, the reconnection is performed by the radio base station. Since the request signal is rejected, the wireless connection for communication by the mobile station is disconnected, and it becomes necessary for the user himself to manually perform a re-transmission procedure, resulting in a problem that serviceability is lowered.

  In addition, after the above-mentioned “Radio Link Failure” has occurred, even when the only cell that has been reselected within a certain period of time is the “Inter-RAT cell”, the user himself / herself manually performs the retransmission procedure. There was a problem that the serviceability was lowered due to necessity.

  Therefore, the present invention has been made in view of the above-described problem, and when a mobile station is communicating with a predetermined cell, “Radio Link Failure” is detected and then reselected. Even when the cell does not hold the setting information (UE Context) related to the mobile station, the mobile station can automatically perform the retransmission procedure without manually performing the retransmission procedure by the user himself / herself. It is an object to provide a mobile station, a mobile switching center, and a mobile communication method.

  A first feature of the present invention is a mobile station that communicates with a mobile switching center via a radio base station, and detects a radio link with the first radio base station that manages the first cell. Cell selection unit configured to perform cell reselection processing for a predetermined period after the failure, and the second cell reselected by the cell selection unit uses the same radio access scheme as the first cell A reconnection request signal transmitter configured to transmit a reconnection request signal to a second radio base station that manages the second cell when it is determined to be a cell; and the second radio base When it is determined that a response signal to the reconnection request signal received from the station rejects reconnection, or it is determined that the second cell is a cell using a radio access scheme different from that of the first cell. Manage the second radio base station To and a recall procedure starting unit configured to start a recall procedure for the mobile switching center and gist of that.

  In the first aspect of the present invention, the retransmission procedure starting unit transmits a signal including an identifier indicating a retransmission procedure to the mobile switching center, thereby retransmitting the mobile switching center. It may be configured to initiate the procedure.

  In the first aspect of the present invention, the retransmission procedure start unit transmits at least one of a service request signal or a mobility management area update signal to the mobile switching center, thereby It may be configured to initiate a retransmission procedure.

  In the first aspect of the present invention, the cell selection unit includes a cell using the same radio access scheme and the same frequency as the first cell, a cell using the same radio access scheme and a different frequency as the first cell, The cell reselection process may be performed in the order of cells using a radio access scheme different from that of the first cell.

  A second feature of the present invention is a mobile switching center that communicates with a mobile station via a radio base station. When the first signal is received from the mobile station, the first signal is retransmitted. A retransmission signal determination unit configured to determine whether the signal is a transmission procedure signal, and the retransmission signal determination unit determines that the first signal is the retransmission procedure signal The gist of the invention is that it includes a setting information update unit configured to delete old setting information related to the mobile station and newly set new setting information related to the mobile station.

  In the second aspect of the present invention, the retransmission signal determination unit determines whether the first signal is a retransmission procedure based on at least one of an information element included in the first signal or a communication state of the mobile station. It may be configured to determine whether or not the signal is a business signal.

  In the second feature of the present invention, when the old setting information is managed by a device different from the mobile switching center, the setting information update unit deletes the old setting information in the another device. The new setting information may be set in the mobile switching center.

  According to a third aspect of the present invention, there is provided a mobile communication method for performing communication between a mobile station and a mobile switching center via a radio base station, wherein the mobile station manages a first cell. A step of performing a cell reselection process for a predetermined period after the detection of the radio link between the mobile station and the mobile station is performed, and the second cell reselected by the mobile station uses the same radio access method as the first cell The mobile station transmits a reconnection request signal to the second radio base station that manages the second cell, and the mobile station receives the reconnection request received from the second radio base station. When it is determined that a response signal to the signal rejects reconnection, or when it is determined that the second cell is a cell using a radio access scheme different from that of the first cell, the second radio base station is Initiate re-call procedure for managed mobile switching center And when the mobile switching center receives a first signal from the mobile station, the step of determining whether the first signal is a retransmission procedure signal; And a step of deleting the old setting information related to the mobile station and newly setting the new setting information related to the mobile station when it is determined that the first signal is the retransmission procedure signal. And

  As described above, according to the present invention, when a mobile station is communicating with a predetermined cell, after the “Radio Link Failure” is detected, the reselected cell is transferred to the mobile station. Even when the setting information (UE Context) is not held, the mobile station that allows the mobile station to automatically perform the retransmission procedure without manually performing the retransmission procedure itself, mobile switching A station and a mobile communication method can be provided.

1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. 1 is a functional block diagram of a mobile switching center according to a first embodiment of the present invention. 4 is a mobile station management information table in the mobile switching center according to the first embodiment of the present invention. FIG. 3 is a functional block diagram of a mobile station according to the first embodiment of the present invention. 3 is a flowchart showing an operation of the mobile station according to the first embodiment of the present invention.

(Configuration of mobile communication system according to the first embodiment of the present invention)
The configuration of the mobile communication system according to the first embodiment of the present invention will be described with reference to FIGS. Note that in all the drawings for explaining the present embodiment, the same reference numerals are given to those having the same function, and repeated explanation is omitted.

  As shown in FIG. 1, the mobile communication system according to the present embodiment includes a mobile station 100, a plurality of radio base stations 200A to 200F, and mobile switching stations 300A and 300B.

  Here, the mobile switching center 300A includes an area (cell or sector) 1A managed by the radio base station 200A, an area (cell or sector) 1B managed by the radio base station 200B, and the radio base station 200C. It is configured to manage the mobility management area 1 formed by the managed area (cell or sector) 1C.

  The mobile switching center 300B is managed by the area (cell or sector) 2A managed by the radio base station 200D, the area (cell or sector) 2B managed by the radio base station 200E, and the radio base station 200F. The mobility management area 2 formed by the area (cell or sector) 2C being managed is managed.

  The mobile switching center 300A is configured to communicate with each mobile station 100 located in the mobility management area 1 (second mobility management area) via any of the radio base stations 200A to 200C. Yes.

  On the other hand, the mobile switching center 300B is configured to communicate with each mobile station 100 located in the mobility management area 2 (first mobility management area) via any of the radio base stations 200D to 200F. Has been.

  Since the configuration of the mobile switching center 300A and the configuration of the mobile switching center 300B are basically the same, the configuration of the mobile switching center 300 will be described below.

  As shown in FIG. 2, the mobile switching center 300 includes a signal transmission / reception unit 302, a retransmission signal determination unit 304 connected to the signal transmission / reception unit 302, and a setting connected to the retransmission signal determination unit 304. And an information updating unit 306.

  The signal transmission / reception unit 302 is configured to transmit and receive signals between the mobile station and the radio base station.

  The signal transmission / reception unit 302 receives, for example, a mobility management area update signal (Tracking Area Update) and a service request signal (Service Request) for reporting that the mobility management area of the mobile station has changed from the mobile station. It is configured.

  The retransmission signal determination unit 304 is configured to determine whether or not the first signal is a retransmission procedure signal when the first signal is received from the mobile station.

  Here, the first signal received from the mobile station is reconfigured as a signal transmitted from the mobile station as a NAS signal or a signal received from the mobile station by the radio base station as a signal addressed to the mobile switching station. It may be a signal that has been generated.

  The retransmission signal determination unit 304 determines whether the received first signal is a retransmission procedure signal based on at least one of the information element included in the received first signal or the communication state of the mobile station. May be configured to determine.

  The retransmission signal determination unit 304 may be configured to use, for example, at least one of a transmission cause or a retransmission identifier as the information element.

  On the other hand, the retransmission signal determination unit 304 manages mobile station information associating “Permanent ID”, “Terminal ID”, “mobile station state”, and “provided service” as shown in FIG. As the status, when the “mobile station status” of the mobile station is “communication”, it is determined that the received first signal is a retransmission procedure signal, and the “mobile station status” of the mobile station is “ If it is “waiting”, it may be determined that the received first signal is a new transmission signal.

  When the retransmission signal determination unit 304 determines that the first signal is a retransmission procedure signal, the setting information update unit 306 deletes the old setting information related to the mobile station and sets the new information related to the mobile station. The configuration information is newly set. However, when the old setting information and the new setting information are the same, the old setting information may be used as it is.

  For example, old setting information (UE Context) related to the mobile station is managed by the mobile switching center 300A, the mobile station moves to the management area of the mobile switching center 300B, and a mobile management area update signal is sent to the mobile switching center. When transmitted to 300B, mobile switching center 300B communicates with mobile switching center A, and deletes old configuration information (UE Context) related to the mobile station in mobile switching center A (another device). The mobile switching center B may be configured to set new setting information (UE Context) related to the mobile station.

  As shown in FIG. 4, the mobile station 100 includes a transmission / reception unit 102, a radio link monitoring unit 104 connected to the transmission / reception unit 102, a cell selection unit 106 connected to the radio link monitoring unit 104, A radio access method determination unit 108 connected to the cell selection unit 106, a signal generation unit 110 connected to the radio access method determination unit 108, and a reception signal determination unit 112 connected to the transmission / reception unit 102 A retransmission notification unit 114 connected to the received signal determination unit 112, and a retransmission procedure start unit 116 connected to the retransmission notification unit 114.

  The transmission / reception unit 102 receives a synchronization signal (Synchronization Signal), a reference signal (Reference Signal), broadcast information (System Information), a signal from a radio base station, a signal from a mobile switching station, and the like of each cell. Or a signal addressed to the radio base station or a signal addressed to the mobile switching center.

For example, the signal from the radio base station and the signal destined for the radio base station are RRC (Radio Resource Control) signals, and the signal from the mobile switching center and the signal destined for the mobile switching station may be NAS signals. The transmission / reception unit 102 is configured to transmit the signal generated by the signal generation unit 110.

  The radio link monitoring unit 104 is configured to monitor a radio link in communication with the first radio base station that manages the first cell.

  The cell selection unit 106 is configured to perform a cell reselection process for a predetermined period after failing to detect a radio link with the first radio base station that manages the first cell.

  Here, the predetermined period may be set as a time for performing the cell selection process until the mobile station 100 transitions from the communication state (RRC_Connected state) to the standby state (RRC_Idle state).

  For example, the cell selection unit 106 includes a cell using the same radio access scheme and the same frequency as the first cell, a cell using the same radio access scheme and a different frequency as the first cell, and a radio access different from the first cell. You may be comprised so that a cell reselection process may be implemented in order of the cell (Inter-RAT cell) using a system.

  The radio access scheme determination unit 108 is configured to determine whether or not the second cell reselected by the cell selection unit 106 is a cell that uses the same radio access scheme as the first cell. Yes.

  For example, the radio access scheme determination unit 108 uses the “GSM scheme”, “UMTS scheme”, “LTE (FDD) scheme”, “LTE (TDD) scheme” as the radio access scheme used in the first cell and the second cell. It may be configured to determine which of the above.

  The signal generator 110 is configured to generate a signal addressed to the radio base station and a signal addressed to the mobile switching center.

  For example, if the radio access scheme determination unit 108 determines that the second cell reselected by the cell selection unit 106 is a cell that uses the same radio access scheme as the first cell, the signal generation unit 110 A connection request signal (RRC Connection Re-establishment) is generated.

  For example, when the retransmission procedure is started by the retransmission procedure start unit 116, the signal generation unit 110 receives at least a NAS service request signal (Service Request) or a mobility management area update signal (Tracking Area Update). It is configured to generate one.

  Here, the signal generation unit 110 may be configured to insert an identifier indicating a retransmission procedure as part of the generated NAS signal.

  For example, the identifier indicating the retransmission may be configured to be inserted as part of the signal transmission reason (Establishment Cause), or may be configured to be inserted as the retransmission identifier. Good.

  The reception signal determination unit 112 is configured to analyze the signal received by the transmission / reception unit 102.

  A signal (RRC Connection Re-establishment Reject) in which the signal received by the transmission / reception unit 102 (response signal to the reconnection request signal received from the second radio base station) is rejected by the reception signal determination unit 112 (RRC Connection Re-establishment Reject) When it is determined that the re-transmission procedure is necessary, the re-transmission notification unit 114 is notified that the re-transmission procedure is necessary.

  When the wireless access method determination unit 108 determines that the reselected second cell is a cell using a wireless access method different from that of the first cell, the retransmission notification unit 114 notifies the retransmission request start unit 116. It is configured to instruct to perform a NAS re-transmission procedure.

  The re-transmission procedure start unit 116 is configured to start a NAS re-transmission procedure in accordance with an instruction from the re-transmission notification unit 114.

(Operation of the mobile communication system according to the first embodiment of the present invention)
With reference to FIG. 5, the operation of the mobile station according to the first embodiment of the present invention will be described.

  As shown in FIG. 5, in Step 1, the mobile station 100 determines whether the detection of a radio link in communication with the first radio base station that manages the first cell has succeeded.

  When the detection of such a radio link fails, in Step 2, the mobile station 100 determines whether or not the cell reselection process (Cell Reselection) is completed during a predetermined period.

  When it is determined that such cell reselection processing has not been completed, in Step 3, the mobile station 100 transitions to a standby state.

  On the other hand, if it is determined that the cell reselection process has been completed, in Step 4, the mobile station 100 determines that the reselected second cell is a cell (Intra-RAT) that uses the same radio access scheme as the first cell. Cell).

  When it is determined that the cell is an intra-RAT cell, in Step 5, the mobile station 100 transmits a reconnection request signal (RRC Connection Re-establishment) to the second radio base station that manages the second cell.

  In Step 6, the mobile station 100 determines whether or not a response signal from the radio base station with respect to the reconnection request signal described above permits reconnection.

  If it is determined in Step S4 that it is not an Intra-RAT cell (is an Inter-RAT cell), and if it is determined in Step 6 that reconnection is not permitted, a NAS retransmission procedure starts in Step 7. Is done.

  On the other hand, if it is determined in Step 6 that reconnection is permitted, communication by the mobile station 100 is continued in Step 8.

(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, when the mobile station 100 is communicating with the first cell, “Radio Link Failure” is detected and then reselected. Even when the second cell does not hold the setting information (UE Context) related to the mobile station 100, the mobile station 100 automatically performs the retransmission procedure without the user performing the retransmission procedure manually. Make it possible to do.

(Example of change)
The operations of the mobile station and mobile switching center described above may be implemented by hardware, may be implemented by a software module executed by a processor, or may be implemented by a combination of both.

  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 a mobile station or a mobile switching center. Further, the storage medium and the processor may be provided in the mobile station or the mobile switching center as a discrete component.

  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.

DESCRIPTION OF SYMBOLS 1, 2 ... Mobility management area 100 ... Mobile station 102 ... Transmission / reception part 104 ... Radio link monitoring part 106 ... Cell selection part 108 ... Radio access system judgment part 110 ... Signal generation part 112 ... Received signal judgment part 114 ... Re-transmission notification part 116 ... Retransmission procedure start unit 200 ... Radio base station 300 ... Mobile switching center 302 ... Signal transmission / reception unit 304 ... Retransmission signal determination unit 306 ... Setting information update unit

Claims (8)

A mobile station that communicates with a mobile switching center via a radio base station,
A cell selection unit configured to perform a cell reselection process for a predetermined period after detection of a radio link with the first radio base station managing the first cell fails;
When it is determined that the second cell reselected by the cell selection unit is a cell that uses the same radio access scheme as the first cell, the second cell is re-established with respect to the second radio base station that manages the second cell. A reconnection request signal transmitter configured to transmit a connection request signal;
When it is determined that a response signal to the reconnection request signal received from the second radio base station rejects reconnection, or the cell uses a radio access scheme different from the first cell And a re-transmission procedure start unit configured to start a re-transmission procedure with respect to the mobile switching center that manages the second radio base station.   The re-transmission procedure start unit is configured to start a re-transmission procedure for the mobile switching center by transmitting a signal including an identifier indicating the re-transmission procedure to the mobile switching center. The mobile station according to claim 1, wherein:   The re-transmission procedure start unit is configured to start a re-transmission procedure for the mobile switching center by transmitting at least one of a service request signal or a mobility management area update signal to the mobile switching center. The mobile station according to claim 1, wherein the mobile station is provided.   The cell selection unit includes a cell using the same radio access scheme and the same frequency as the first cell, a cell using the same radio access scheme and a different frequency as the first cell, and a radio access scheme different from the first cell. The mobile station according to any one of claims 1 to 3, wherein cell reselection processing is performed in the order of cells using. A mobile switching center that communicates with a mobile station via a radio base station,
A retransmission signal determination unit configured to determine whether or not the first signal is a retransmission procedure signal when the first signal is received from the mobile station;
When the retransmission signal determination unit determines that the first signal is the retransmission procedure signal, the old setting information related to the mobile station is deleted, and new setting information related to the mobile station is newly added. A mobile switching center comprising a setting information updating unit configured to set.   The retransmission signal determination unit determines whether or not the first signal is a retransmission procedure signal based on at least one of an information element included in the first signal or a communication state of the mobile station. The mobile switching center according to claim 5, wherein the mobile switching center is configured to do so.   When the old setting information is managed by a device different from the mobile switching center, the setting information update unit deletes the old setting information in the different device, and the new setting is stored in the mobile switching center. The mobile switching center according to claim 5 or 6, wherein the mobile switching center is configured to set information. A mobile communication method for performing communication between a mobile station and a mobile switching center via a radio base station,
A step of performing a cell reselection process for a predetermined period after the mobile station fails to detect a radio link with the first radio base station managing the first cell;
When the mobile station determines that the reselected second cell is a cell using the same radio access scheme as the first cell, a reconnection request is made to the second radio base station that manages the second cell. Transmitting a signal;
When the mobile station determines that a response signal to the reconnection request signal received from the second radio base station rejects reconnection, or when the second cell is different from the first cell If it is determined that the cell is a cell using a method, starting a re-transmission procedure for a mobile switching center that manages the second radio base station;
When the mobile switching center receives a first signal from the mobile station, determines whether the first signal is a retransmission procedure signal;
If the mobile switching center determines that the first signal is the retransmission procedure signal, the mobile switching station deletes the old setting information related to the mobile station and newly sets the new setting information related to the mobile station A mobile communication method comprising the steps of:

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