JP6063711B2 - Handover method and mobile station - Google Patents

Description

  The present invention relates to a handover method and a mobile station.

  In the LTE (Long Term Evolution) system, CoMP (Coordinated Multi-Point transmission / reception, multipoint coordinated transmission / reception) is studied for the purpose of improving the throughput of the mobile station UE located at the cell edge. ing.

  Such CoMP is used for transmission / reception and scheduling of a shared data channel signal between a plurality of transmission points (for example, a radio base station eNB, a radio equipment RRE (Remote Radio Equipment), a relay node RN, etc.) that are geographically separated. This is a technology for cooperative control of beam forming and the like.

3GPP contribution R2-124926 3GPP TS36.331 3GPP TR 36.819

  However, in the current LTE scheme, the mobile station UE performs handover from the cell # 1 under the radio base station eNB # 1 performing CoMP to the cell # 2 under the radio base station eNB # 2 performing CoMP. In this case, the radio base station eNB # 2 does not specify whether to take over the setting information related to the CSI-RS (Channel State Information Reference Signal) resource used in the radio base station eNB # 1. was there.

  Therefore, the present invention has been made in view of the above-described problems, and the mobile station UE performs CoMP from the cell # 1 subordinate to the radio base station eNB # 1 performing CoMP. When performing handover to cell # 2 under # 2, the radio base station eNB # 2 may determine whether to take over the setting information related to the CSI-RS resource used in the radio base station eNB # 1 An object of the present invention is to provide a handover method and a mobile station.

  A first feature of the present invention is that, when multipoint coordinated transmission / reception using a plurality of transmission points is performed in the first radio base station and the second radio base station, the mobile station A handover method for performing handover from a cell under a station to a cell under the second radio base station, wherein the mobile station transmits the transmission point under the first radio base station in a cell under the second radio base station. Enabling the setting information related to the channel state indicator and the reference code resource used in step 1, and the physical received by the mobile station from the first radio base station in the cell under the second radio base station Releasing the setting information related to the channel state indicator and the reference code resource specified by the setting information; and In a cell under the control Chikyoku, and summarized in that a step of adding the setting information related to the channel state indicator and reference numerals resource specified by the physical setting information received from the first radio base station.

  The second feature of the present invention is that when multipoint coordinated transmission / reception processing using a plurality of transmission points is performed in the first radio base station and the second radio base station, the subordinates of the first radio base station A mobile station configured to be able to perform handover from a cell to a cell under the second radio base station, and manages setting information related to a channel state indicator and a reference code resource used at the transmission point A setting unit configured as described above, and when the handover is performed, the setting unit is configured to transmit, at the transmission point under the first radio base station, in the cell under the second radio base station. The configuration information related to the used channel state indicator and reference code resource is validated, and the physical configuration information received from the first radio base station. Is configured to release the setting information related to the channel state indicator and the reference code resource specified by, and add the setting information related to the channel state indicator and the reference code resource specified by the physical setting information. It is a summary.

  As described above, according to the present invention, the mobile station UE performs cell # 1 subordinate to the radio base station eNB # 2 performing CoMP from the cell # 1 subordinate to the radio base station eNB # 1 performing CoMP. Handover method and mobile station capable of determining whether or not to take over the setting information related to the CSI-RS resource used in the radio base station eNB # 1 in the radio base station eNB # 2 Can be provided.

1 is an overall configuration diagram of a mobile communication system according to a 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. It is a figure which shows an example of the information element "PhysicalConfigDedicated" transmitted by the wireless base station which concerns on the 1st Embodiment of this invention. FIG. 3 is a sequence diagram for explaining an operation of the mobile communication system according to the first embodiment of the present invention. 3 is a flowchart for explaining an operation of the mobile station according to the first embodiment of the present invention. It is a figure for demonstrating operation | movement of the mobile station which concerns on the 1st Embodiment of this invention.

(Mobile communication system according to the first embodiment of the present invention)
With reference to FIG. 1 thru | or FIG. 6, the mobile communication system which concerns on the 1st Embodiment of this invention is demonstrated. In the present embodiment, an LTE mobile communication system will be described as an example of the mobile communication system according to the present embodiment, but the present invention is also applicable to mobile communication systems other than the LTE system.

  As shown in FIG. 1, the mobile communication system according to the present embodiment includes a radio base station eNB # 1 and a radio base station eNB # 1.

  Here, the radio base station eNB # 1 and the radio base station eNB # 2 are configured to be able to perform CoMP, particularly downlink CoMP.

  Here, in the mobile communication system according to the present embodiment, cells under the radio base station eNB # 1 (cells transmitted and received by transmission points under the radio base station eNB # 1) and cells under the radio base station eNB # 2 (Cell in which transmission / reception is performed by a transmission point under radio base station eNB # 2) is configured to be able to provide CoMP, that is, a cell and radio base station eNB under radio base station eNB # 1 It is assumed that cells under # 2 are configured to be a CoMP support area.

  Such downlink CoMP includes “JT (Joint Transmission)”, “DCS (Dynamic Cell Selection)”, and “CS / CB (Coordinated Scheduling / Beamforming)”.

  Here, “JT” is a process of transmitting the shared data channel signal to the mobile station UE from a plurality of cells, that is, from cells other than the serving cell.

  “DCS” is a process of selecting one cell at a high speed based on channel quality information (CQI) and transmitting a shared data channel signal from the selected cell to the mobile station UE.

  Furthermore, “CS / CB” is a process of coordinating scheduling and beamforming between the serving cell and the neighboring cells.

  In addition, the cell under the radio base station eNB # 1 and the cell under the radio base station eNB # 2 are configured to transmit CSI-RS in addition to CRS (Cell Specific Reference Signal).

  Here, the CRS is a reference signal defined in the LTE Rel-8 / 9 scheme, and is a reference signal that is commonly set for all the mobile stations UE in each cell.

  On the other hand, CSI-RS is a reference signal defined in the LTE Rel-10 or later scheme, and is a reference signal that is individually set for each mobile station UE using an RRC (Radio Resource Control) message. .

  The CSI-RS may be used for quality measurement processing (measurement) such as the above-described transmission point (CoMP target candidate), serving cell, neighboring cell (handover destination candidate), and transmission in which CoMP is performed. It may be used to measure CQI in points or serving cells.

  Note that the CSI-RS used for the quality measurement process described above and the CSI-RS used for measuring the CQI described above may be the same or different.

  For example, the CSI-RS used for the quality measurement process and the CSI- used for measuring the CQI are measured based on the measurement accuracy in the quality measurement process and the requirements for the measurement accuracy of the CQI. A decision can be made as to whether the RSs are the same or different.

  Further, the CSI-RS arrangement density is configured to be lower than the CRS arrangement density.

  In addition, when CoMP is performed in a cell under the radio base station eNB # 1 (or a cell under the radio base station eNB # 2), the same PCI (Physical Cell ID) is used in the cell (transmission point). It may be configured to be used, or may be configured to use a different PCI.

  In the present embodiment, as illustrated in FIG. 1, when CoMP is performed in the radio base station eNB # 1 and the radio base station eNB # 2, the mobile station UE is a cell under the radio base station eNB # 1. A case will be described in which handover is performed from a cell to a cell under radio base station eNB # 2.

  In the mobile communication system according to the present embodiment, the cell under the radio base station eNB # 1 and the cell under the radio base station eNB # 2 may be a macro cell or a small cell. ).

  For example, in the mobile communication system according to the present embodiment, the cell under the radio base station eNB # 1 is a macro cell, the cell under the radio base station eNB # 2 is a small cell, and the radio base station eNB # 1 The cell under radio base station eNB # 2 may be arranged in the coverage area of the cell.

  As shown in FIG. 2, the mobile station UE according to the present embodiment includes a receiving unit 11 and a setting unit 12.

  The receiving unit 11 is configured to receive various signals from the radio base station eNB # 1 and the radio base station eNB # 2.

  For example, the reception unit 11 receives from the radio base station eNB # 1 or the radio base station eNB # 2 a control signal related to the above handover, for example, “RRCConnectionReconfiguration” including an information element “MobilityControlInfo” including the information element “PhysicalConfigDedicated”. It is configured to receive.

  FIG. 3 shows an example of the format of the information element “PhysicalConfigDedicated”.

  The setting unit 12 is configured to manage setting information related to the CSI-RS resource used at the transmission point.

  The setting information related to the CSI-RS resource includes “AntennaInfoDedConfig”, “CSI-RS-Config2”, “CSI-process”, “CSI-IM-Config”, “CQI-ReportPeriodicExt”, and the like.

  Further, when a handover is performed from a cell under the radio base station eNB # 1 of the mobile station UE to a cell under the radio base station eNB # 2, the setting unit 12 The configuration information related to the CSI-RS resource used at the transmission point under the radio base station eNB # 1 is validated, and the CSI-RS resource specified by “PhysicalConfigDedicated” received from the radio base station eNB # 1 It is configured to release the setting information and add the setting information related to the CSI-RS resource specified by the “PhysicalConfigDedicated”.

  Hereinafter, with reference to FIG. 4 to FIG. 6, in the mobile communication system according to the present embodiment, the handover of the mobile station UE from the cell under the radio base station eNB # 1 to the cell under the radio base station eNB # 2 is performed. A description will be given of the operation at the time.

  As illustrated in FIG. 4, in step S1001, the radio base station eNB # 1 transmits “RRCConnectionReconfiguration” including an information element “MobilityControlInfo” including the information element “PhysicalConfigDedicated” to the mobile station UE.

  In step S1002, the mobile station UE sets the CSI-RS resource used at the transmission point under the radio base station eNB # 1 in the cell under the radio base station eNB # 2 based on the information element “PhysicalConfigDedicated”. It is determined whether or not to take over each of the setting information.

  Here, the operation in step S1002 will be described with reference to FIGS.

  In step S101, the mobile station UE determines to validate the setting information related to the CSI-RS resource used at the transmission point under the radio base station eNB # 1.

  For example, the RRC layer of the mobile station UE is set to “AntennaInfoDedConfig”, “CSI-RS-Config2”, “CSI-process” set in the cell (transmission point) under the radio base station eNB # 1 with respect to the physical layer. "," CSI-IM-Config ", and" CQI-ReportPeriodicExt "are instructed to continue to be used in a cell (transmission point) under the radio base station eNB # 2 (see FIG. 6).

  In step S102, the mobile station UE determines to release the setting information related to the CSI-RS resource specified by the information element “PhysicalConfigDedicated” received from the radio base station eNB # 1.

  For example, when the received information element “PhysicalConfigDedicated” includes “antenaInfoDedConfigToReleaseList” (see FIG. 3), the RRC layer of the mobile station UE is included in “antennaInfoDedConfigToResetToResetToResetToResetToRelistToResetList Release "antennaInfoDedConfig".

  Next, when the received information element “PhysicalConfigDedicated” includes “CSI-RS-ConfigToReleaseList” (see FIG. 3), the RRC layer of the mobile station UE includes “CSI-RS-ConfigToReleaseList”. “CSI-RS-Config2” associated with “CSI-RS-Config-Identity” is released.

  Next, when the received information element “PhysicalConfigDedicated” includes “CSI-ProcessToReleaseList” (see FIG. 3), the RRC layer of the mobile station UE includes “CSI-ProcessIdentity” included in “CSI-ProcessToReleaseList”. Releases the “CSI-Process” associated with.

  Next, when “CSI-IM-ConfigToReleaseList” is included in the received information element “PhysicalConfigDedicated” (see FIG. 3), the RRC layer of the mobile station UE includes “CSI-IM-ConfigToReleaseList”. Release "CSI-IM-Config" associated with "IMR-Identity".

  Next, when the received information element “PhysicalConfigDedicated” includes “CQI-ReportPeriodicExtToReleaseList” (see FIG. 3), the RRC layer of the mobile station UE includes “CQI-ReportPeriodPeritlExitToReListIResetIResetIResetId” Release “CQI-ReportPeriodicExt” associated with.

  In step S103, the mobile station UE adds setting information related to the CSI-RS resource specified by the received information element “PhysicalConfigDedicated”.

  For example, when the received information element “PhysicalConfigDedicated” includes “antenaInfoDedConfigConfigAddAddModList” (see FIG. 3), the currently set “AntnaInfoDedConfigConfig” is different from the currently set “AntnaInfoDedConfig”. “AntennaInfoDededConfig-Id” associated with “antennaInfoDedConfig-Id” is added.

  On the other hand, when the received information element “PhysicalConfigDedicated” includes “antenaInfoDedConfigToAddModList” (see FIG. 3), the RRC layer of the mobile station UE has the same “AntnaInfoDedConfigConfig” in the “AntnaInfoDedConfig”. The content (parameter) of “antennaInfoDedConfig” associated with “antennaInfoDedConfig-Id” is modified.

  Next, the RRC layer of the mobile station UE, when “CSI-RS-ConfigToAddModList” is included in the received information element “PhysicalConfigDedicated” (see FIG. 3), the currently set “CSI-RS-Config- "CSI-RS-Config-ConfigConfig2" associated with "CSI-RS-Config-Identity" in "CSI-RS-ConfigToAddModList" different from "Identity" is added.

  On the other hand, when the received information element “PhysicalConfigDedicated” includes “CSI-RS-ConfigToAddModList” (see FIG. 3), the RRC layer of the mobile station UE currently sets “CSI-RS-Config-Identity”. The content (parameter) of “CSI-RS-Config-Identity” associated with “CSI-RS-Config-Identity” in the same “CSI-RS-ConfigToAddModList” is modified.

  Next, when the received information element “PhysicalConfigDedicated” includes “CSI-ProcessToAddModList” (see FIG. 3), the RRC layer of the mobile station UE differs from the currently set “CSI-ProcessIdentity”. “CSI-Process” associated with “CSI-Process Identity” in “CSI-Process To Add Mod List” is added.

  On the other hand, if the received information element “PhysicalConfigDedicated” includes “CSI-ProcessToAddModList” (see FIG. 3), the RRC layer of the mobile station UE has the same “CSI-ProcessIdentity” as the currently set “CSI-ProcessIdentity”. The content (parameter) of “CSI-Process” associated with “CSI-ProcessIdentity” in “ProcessToAddModList” is modified.

  Next, the RRC layer of the mobile station UE, when “CSI-IM-ConfigToAddModList” is included in the received information element “PhysicalConfigDedicated” (see FIG. 3), what is currently set “IMR-Identity”? Add “CSI-IM-Config” associated with “IMR-Identity” in a different “CSI-IM-ConfigToAddModList”.

  On the other hand, when the received information element “PhysicalConfigDedicated” includes “CSI-IM-ConfigToAddModList” (see FIG. 3), the RRC layer of the mobile station UE is the same as the currently set “IMR-Identity”. The content (parameter) of “CSI-IM-Config” associated with “IMR-Identity” in “CSI-IM-ConfigToAddModList” is modified.

  Next, when the received information element “PhysicalConfigDedicated” includes “CQI-ReportPeriodicExtToAddModList” (see FIG. 3), the RRC layer of the mobile station UE is different from the currently set “CQI-ReportPeriodId”. “CQI-ReportPeriodicExtEx” associated with “CQI-ReportPeriodicExtId” in “CQI-ReportPeriodicExtToAddModList” is added.

  On the other hand, when the received information element “PhysicalConfigDedicated” includes “CQI-ReportPeriodicExtToAddModList” (see FIG. 3), the RRC layer of the mobile station UE has the same “CQI-ReportPeriodicExidQ” as currently set. The content (parameter) of “CQI-ReportPeriodicExt” associated with “CQI-ReportPeriodicExtId” in “ReportPeriodicExtToAddModList” is modified.

  In step S1003, the mobile station UE transmits “RRCConnectionReconfigurationComplete” to the radio base station eNB # 2.

  According to the mobile communication system according to the present embodiment, when the same transmission point as the radio base station eNB # 1 can be used in the radio base station eNB # 2 after the above-described handover, the CSI-RS resource setting is performed. The setting information of the CSI-RS resource used in the radio base station eNB # 1 can be continued in the cell (transmission point) under the radio base station eNB # 2 without having to reset the information.

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

  The first feature of the present embodiment is that CoMP (multipoint) using a plurality of transmission points in the radio base station eNB # 1 (first radio base station) and the radio base station eNB # 2 (second radio base station). When a coordinated transmission / reception is performed, the mobile station UE performs handover from a cell under the radio base station eNB # 1 to a cell under the radio base station eNB # 2, wherein the mobile station UE The step of validating the setting information related to “CSI-RS resources (channel state indicators and reference code resources)” used in the transmission point under the radio base station eNB # 1 in the cell under the base station eNB # 2 The mobile station UE receives the information element “PhysicalConfig” received from the radio base station eNB # 1 in the cell under the cell radio base station eNB # 2. The step of releasing the setting information related to the CSI-RS resource specified by “gDedicated (physical setting information)” and the mobile station UE received from the radio base station eNB # 1 in the cell under the radio base station eNB # 2 And a step of adding setting information related to the CSI-RS resource specified by the information element “PhysicalConfigDedicated”.

  The second feature of the present embodiment is that when the CoMP using a plurality of transmission points is performed in the radio base station eNB # 1 and the radio base station eNB # 2, cells under the radio base station eNB # 1 Mobile station UE configured to be able to be handed over to a cell under radio base station eNB # 2 and configured to manage setting information related to CSI-RS resources used at a transmission point When the above handover is performed, the setting unit 12 was used at a transmission point under the radio base station eNB # 1 in the cell under the radio base station eNB # 2. The setting information related to the CSI-RS resource is validated, and the information element “PhysicalConfigDedicated” received from the radio base station eNB # 1 is used. Releasing the setting information related to CSI-RS resource specified, it is a gist that is configured to add a setting information related to CSI-RS resource designated by the information element "PhysicalConfigDedicated".

  Note that the operations of the radio base station eNB and the mobile station UE 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 the radio base station eNB or the mobile station UE. Further, the storage medium and the processor may be provided as a discrete component in the radio base station eNB or the mobile station UE.

  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.

eNB ... radio base station UE ... mobile station 11 ... receiving unit 12 ... setting unit

Claims (2)

When multipoint coordinated transmission / reception using a plurality of transmission points is performed in the first radio base station and the second radio base station, the mobile station transmits the second radio from the cell under the first radio base station. A handover method for performing handover to a cell under a base station,
The mobile station, in a cell under the second radio base station, enabling the setting information related to the channel state indicator and reference code resources used at the transmission point under the first radio base station; ,
The mobile station releasing, in a cell under the second radio base station, setting information related to a channel state indicator and a reference code resource specified by physical setting information received from the first radio base station; ,
The mobile station adding configuration information related to a channel state indicator and a reference code resource specified by physical configuration information received from the first radio base station in a cell under the second radio base station; A handover method characterized by comprising: When multipoint coordinated transmission / reception using a plurality of transmission points is performed in the first radio base station and the second radio base station, a cell under the second radio base station is subordinate to a cell under the first radio base station. A mobile station configured to be handed over to a cell,
A setting unit configured to manage setting information related to a channel state indicator and a reference code resource used at the transmission point;
When the handover is performed, the setting unit relates to a channel state indicator and a reference code resource used in the transmission point under the first radio base station in the cell under the second radio base station. The channel information specified by the physical setting information is released by releasing the setting information related to the channel state indicator and the reference code resource specified by the physical setting information received from the first radio base station. A mobile station configured to add setting information related to an indicator and a reference code resource.

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