WO2010137155A1 - Système de communication mobile, station de base, station mobile, et procédé de communication sans fil - Google Patents

Système de communication mobile, station de base, station mobile, et procédé de communication sans fil Download PDF

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Publication number
WO2010137155A1
WO2010137155A1 PCT/JP2009/059802 JP2009059802W WO2010137155A1 WO 2010137155 A1 WO2010137155 A1 WO 2010137155A1 JP 2009059802 W JP2009059802 W JP 2009059802W WO 2010137155 A1 WO2010137155 A1 WO 2010137155A1
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Prior art keywords
cell
base station
enb
station
received
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PCT/JP2009/059802
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English (en)
Japanese (ja)
Inventor
紀明 河野
秀和 佐藤
秀雄 加藤
義久 中山
晋一郎 小林
昌代 寺田
弘幸 長島
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富士通株式会社
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Priority to PCT/JP2009/059802 priority Critical patent/WO2010137155A1/fr
Publication of WO2010137155A1 publication Critical patent/WO2010137155A1/fr

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W36/00—Hand-off or reselection arrangements
    • H04W36/08—Reselecting an access point
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W92/00—Interfaces specially adapted for wireless communication networks
    • H04W92/16—Interfaces between hierarchically similar devices
    • H04W92/20—Interfaces between hierarchically similar devices between access points

Definitions

  • the present invention relates to a mobile communication system, a base station, a mobile station, and a radio communication method.
  • FIG. 28 is a sequence diagram illustrating an example of a processing procedure of a handover process in a conventional mobile communication system.
  • the mobile station transmits a cell formed by a base station (handover source base station, hereinafter referred to as HO source base station) that is currently communicating with another base station (handover destination base station, hereinafter,
  • HO source base station a base station that is currently communicating with another base station
  • handover destination base station a handover request is transmitted to the HO destination base station via the HO source base station (step S001).
  • the handover request includes information necessary when the HO destination base station executes the handover process, such as cell identification information formed by the HO destination base station and information on the mobile station.
  • the HO destination base station that has received the handover request determines whether or not the mobile station can be accepted (step S002). If the HO destination base station determines that the mobile station can be accepted, the HO destination base station secures radio resources used for radio communication with the mobile station (step S003), and sends a handover request response signal (Handover Request Acknowledge) to the HO source base. Transmit to the station (step S004).
  • the HO source base station transmits a handover command signal (Handover Command) to the mobile station (step S005).
  • the handover instruction signal includes information related to radio resources used by the mobile station for radio communication with the HO destination base station.
  • the mobile station When the mobile station receives the handover instruction signal, the mobile station secures radio resources according to the radio resource information included in the handover instruction signal, and enables communication with the HO destination base station (step S006). After that, the mobile station transmits / receives a synchronization establishment signal, timing information, etc. in order to establish frame synchronization and time alignment adjustment with the HO destination base station. A handover completion signal is transmitted to the station (step S007). Then, the HO destination base station that has received the handover complete signal transmits a radio resource release instruction signal to the HO source base station (step S008), and the HO source base station is based on the radio resource release instruction signal. The radio resource is released (step S009). As a result, the handover process is completed, and the mobile station can continue radio communication with the HO destination base station.
  • the handover process is a relatively complicated process that requires securing and releasing radio resources and exchanging various signals associated with these processes. It takes a long time to complete the process. Therefore, especially in areas where small-zone cells with small cell radii are located, where handovers are likely to occur, the continuous generation of handovers increases the data transfer between base stations and secures radio resources. Since it takes time to open or release the communication, there is a possibility that the communication quality is deteriorated or the communication is interrupted.
  • the present invention has been made in view of the above, and even when a mobile station frequently repeats movement between cells, it is possible to prevent deterioration in communication quality and interruption of communication due to handover processing. It is an object to provide a mobile communication system, a base station, a mobile station, and a radio communication method.
  • the mobile communication system disclosed in the present case is, as one aspect, a mobile station and a mobile station when receiving a handover request from the mobile station.
  • a mobile communication system including a plurality of base stations that execute a handover process for securing radio resources for communication and enabling communication with the mobile station, wherein the mobile station includes a plurality of base stations
  • a group cell construction request transmitting means for transmitting a group cell construction request for requesting construction of a group cell, which is a virtually integrated cell formed by each station, to the base station in the area;
  • Dependent cell determination means for determining a dependent cell included in a group cell having a cell formed by the own station as a reference cell when the group cell construction request is received from the mobile station
  • Radio resource information transmitting means for transmit
  • the base station, the mobile station, and the radio communication method disclosed in this case even when the mobile station frequently repeats movement between cells, the communication quality associated with the handover process is improved. There is an effect that it is possible to prevent deterioration and interruption of communication.
  • FIG. 1 is a diagram illustrating the configuration of the mobile communication system according to the first embodiment.
  • FIG. 2 is a conceptual diagram of the group cell according to the first embodiment.
  • FIG. 3 is a diagram for explaining how a group cell is constructed for each UE.
  • FIG. 4 is a block diagram of the configuration of the eNB according to the first embodiment.
  • FIG. 5 is a diagram for explaining processing executed by the scheduling unit and the data buffer unit.
  • FIG. 6 is a block diagram of the configuration of the UE according to the first embodiment.
  • FIG. 7 is a sequence diagram illustrating an example of a processing procedure of a handover process in the mobile communication system according to the first embodiment.
  • FIG. 8 is a flowchart illustrating an outline of a processing procedure of the eNB 1M according to the present embodiment.
  • FIG. 9 is a sequence diagram illustrating an example of a processing procedure of master cell determination processing according to the present embodiment.
  • FIG. 10 is a sequence diagram illustrating an example of the processing procedure of the slave cell determination processing according to the present embodiment.
  • FIG. 11 is a sequence diagram illustrating an example of a processing procedure of data transfer processing and data sharing management processing according to the present embodiment.
  • FIG. 12 is a sequence diagram illustrating an example of a processing procedure of the radio resource sharing process and the retransmission control process according to the present embodiment.
  • FIG. 13A is a sequence diagram illustrating an example of a processing procedure of a master cell change process when the new master cell is a cell formed by the eNB 1M.
  • FIG. 13-2 is a sequence diagram illustrating an example of a processing procedure of a master cell change process when the new master cell is a cell other than the cell formed by the eNB 1M.
  • FIG. 14 is a sequence diagram illustrating an example of the processing procedure of the slave cell change processing according to the present embodiment.
  • FIG. 15 is a sequence diagram illustrating a processing procedure of master cell determination processing when a group cell construction request is automatically transmitted.
  • FIG. 16 is a block diagram illustrating a configuration of a UE according to another embodiment.
  • FIG. 17A is a sequence diagram illustrating another example of the processing procedure of the master cell change process when the new master cell is a cell formed by the eNB 1M.
  • FIG. 17-2 is a sequence diagram illustrating another example of the processing procedure of the master cell change process when the new master cell is a cell other than the cell formed by the eNB 1M.
  • FIG. 18 is a block diagram illustrating a configuration of a UE according to another embodiment.
  • FIG. 19 is a sequence diagram illustrating another example of the processing procedure of the slave cell change process.
  • FIG. 20 is a sequence diagram illustrating an example of a processing procedure of a slave cell determination process when a slave cell is determined based on cell position coordinate information received from each eNB.
  • FIG. 21A is a sequence diagram illustrating a processing procedure when it is determined that the UE is moving and the number of slave cells is increased.
  • FIG. 21-2 is a sequence diagram illustrating a processing procedure when it is determined that the UE is stationary and the number of slave cells is decreased.
  • FIG. 22 is a sequence diagram illustrating an example of a processing procedure when the transmission power in the group cell is different.
  • FIG. 23 is a sequence diagram illustrating an example of a processing procedure when downlink transmission power is changed based on feedback information from the UE.
  • FIG. 24-1 is a diagram illustrating a state in which some eNBs 1S do not perform data transmission to the UE.
  • FIG. 24-2 is a diagram illustrating a state in which the eNB 1S that does not perform data transmission to the UE is changed as the UE moves.
  • FIG. 25 is a diagram illustrating an example of a processing procedure when dynamic control of a downlink power transmission target is performed.
  • FIG. 26 is a sequence diagram illustrating a processing procedure of uplink transmission power control processing.
  • FIG. 27 is a sequence diagram showing a processing procedure for uplink transmission power control processing based on reception power of pilot signals received via a master cell and a slave cell.
  • FIG. 28 is a sequence diagram illustrating an example of a processing procedure of a handover process in a conventional mobile communication system.
  • FIG. 1 is a diagram showing a configuration of a mobile communication system according to the present embodiment
  • FIG. 2 is a conceptual diagram of a group cell according to the present embodiment
  • FIG. 3 is a diagram for explaining how a group cell is constructed for each UE FIG.
  • a packet communication system based on 3GPP-LTE (3rd Generation Partnership Project Long Term Evolution) standard will be described as an example of a mobile communication system.
  • 3GPP-LTE 3rd Generation Partnership Project Long Term Evolution
  • the mobile communication system S includes eNBs (evolved Node-B) 1a to 1j, UEs (User Equipment) 2a and 2b, and MME / UPE (Mobile Management Entity / User Plane). Entity) 3.
  • eNBs evolved Node-B
  • UEs User Equipment
  • MME Mobile Management Entity / User Plane
  • the eNBs 1a to 1j correspond to the base stations according to the present embodiment, and are wireless communication apparatuses that communicate with the UEs 2a and 2b existing in the local station cell via wireless links.
  • the radio link includes a downlink (DL) that is a direction from the eNBs 1a to 1j to the UEs 2a and 2b, and an uplink (UL) that is the opposite direction.
  • DL downlink
  • UL uplink
  • RNC Radio Network Controller
  • Node-B base station
  • SAE Long Term Evolution / System Architecture Evolution
  • an eNB enhanced Node-B
  • the eNBs 1a to 1j according to the present embodiment have both the Node-B function and the RNC function.
  • the function of controlling the handover process etc.
  • eNBs are connected to each other using a communication interface called X2 (hereinafter referred to as “X2 interface”).
  • X2 interface is a newly added interface in 3GPP-LTE.
  • various signals can be directly transferred between the eNBs.
  • eNB1 arbitrary eNBs 1a to 1j among eNBs 1a to 1j are simply referred to as “eNB1”.
  • the UEs 2a and 2b are mobile stations such as portable terminals, and communicate with other UEs, external packet networks, and the like via the eNB 1 that forms a cell in the area.
  • UE2 arbitrary UEs 2a and 2b out of UEs 2a and 2b are simply referred to as “UE2”.
  • MME / UPE3 corresponds to a host device of eNB1, and has a function of managing and controlling a plurality of eNB1, a function of managing location registration of UE2, a function of transmitting and receiving messages between UE2 and an external packet network, etc. It is a core network system device.
  • ENB1 and MME / UPE3 are connected to each other by a communication interface called S1 (hereinafter referred to as “S1 interface”). Similar to the X2 interface, the S1 interface is an interface defined in 3GPP-LTE.
  • the mobile communication system S includes ten eNBs 1a to 1j and two UEs 2a and 2b, but the number of eNBs and the number of UEs are not limited thereto.
  • each eNB 1a to 1j forms one or a plurality of cells. Specifically, as shown in FIG. 2, eNB 1a forms cells 5a to 5c, eNB 1b forms cells 5d to 5f, eNB 1c forms cells 5g to 5i, and eNB 1d forms cells 5j and 5k.
  • the eNB 1e forms cells 5l and 5m.
  • eNB 1f forms cells 5n and 5o
  • eNB 1g forms cells 5p and 5q
  • eNB 1h forms cells 5r to 5t
  • eNB 1i forms cell 5u
  • eNB 1j forms cells 5v to 5x.
  • any of the cells 5a to 5x is simply referred to as “cell 5”.
  • a group cell that is a cell in which cells formed by a plurality of eNBs 1 are virtually integrated is constructed.
  • the UE 2a receives a predetermined operation from the user, the UE 2a transmits a group cell construction request to the eNB 1a that forms the cell 5a being located.
  • the eNB 1a that has received the group cell construction request from the UE 2a constructs the group cell 50 using the cell 5a in which the UE 2a is located as a reference cell.
  • the eNB 1a determines a dependent cell.
  • the subordinate cell is a cell 5 other than the reference cell included in the group cell 50.
  • the eNB 1a determines a neighboring cell of the cell 5a that is the reference cell as a subordinate cell.
  • the eNB 1a determines a cell adjacent to the cell 5a as a dependent cell. That is, as illustrated in FIG. 2, the eNB 1a determines the cells 5b and 5c formed by the own station, the cells 5e and 5e formed by the eNB 1b, and the cells 5g and 5i formed by the eNB 1c as subordinate cells.
  • the eNB 1a determines radio resources for communication with the UE 2a, which are allocated in common to the eNBs 1b and 1c forming the dependent cells and the own station. Specifically, the eNB 1a acquires the resource allocation status information from the eNBs 1b and 1c forming the dependent cells, and is common to the local station and the eNB 1b and 1c from the acquired resource allocation status information and the resource allocation status information of the local station. Identify available radio resources.
  • the eNB 1a determines the specified free radio resource as a radio resource for commonly allocating to the eNBs 1b and 1c and the own station, and sets information on the determined radio resource (hereinafter referred to as “radio resource information”) to the eNB 1b, Send to 1c.
  • radio resource information information on the determined radio resource
  • eNB1b and 1c which received eNB1a and radio
  • the eNB 1a transfers data to be transmitted to the UE 2a to the eNB 1b and 1c.
  • eNB1a and eNB1b, 1c transmit the data to UE2a simultaneously using the radio
  • FIG. the data for the UE 2a is transmitted not only from the cell 5a where the UE 2a is located, but also from the other cells 5b, 5c, 5e, 5g, and 5i that constitute the group cell 50.
  • the mobile communication system S virtually integrates the plurality of cells 5 as a group cell by sharing the radio resources for communication with the UE 2 among the plurality of cells 5. .
  • the UE 2 can treat the group cell 50 virtually as a single cell.
  • the eNB 1 does not need to perform a handover process even when the UE 2 moves between the cells 5 in the group cell 50. As a result, even when the UE 2 frequently moves to another cell 5 in the group cell 50, it is possible to prevent communication quality deterioration and communication interruption caused by the handover process.
  • eNB1M which forms a master cell
  • eNB1S eNB1 which forms only a slave cell
  • the group cell 50 is constructed in units of UE2.
  • the group cell 50a constructed for the UE 2a is a group cell in which the eNB 1a is the eNB 1M and the eNBs 1b and 1c are the eNB 1S.
  • the group cell 50a uses the cell 5a formed by the eNB 1a as a master cell, and sets the cells 5b and 5c of the eNB 1a, the cells 5e and 5f of the eNB 1b, and the cells 5g and 5i of the eNB 1c as slave cells.
  • the group cell 50b constructed for the UE 2b is a group cell in which the eNB 1b is eNB 1M and the eNBs 1a, 1c, 1h, and 1j are eNB 1S. Specifically, the group cell 50b uses the cell 5e formed by the eNB 1b as a master cell, the cell 5a of the eNB 1a, the cells 5d and 5f of the eNB 1b, the cells 5g and 5i of the eNB 1c, the cell 5t of the eNB 1h, and the eNB 1j.
  • the cell 5v is a slave cell.
  • each eNB 1 manages for each UE 2 whether the cell formed by itself is a master cell or a slave cell.
  • group cell 50 arbitrary group cells 50a and 50b after group cells 50a and 50b constructed for each UE 2a and 2b are simply referred to as “group cell 50”.
  • the mobile communication system S according to the present embodiment changes the master cell and the slave cell that configure the group cell 50 as the UE 2 moves. For example, in the mobile communication system S according to the present embodiment, when the UE 2 moves to the end of the group cell 50, the slave cell is reconstructed, and when the communication quality between the UE 2 and the master cell deteriorates, the master cell is changed. Do.
  • FIG. 4 is a block diagram illustrating a configuration of the eNB 1 according to the present embodiment.
  • the eNB 1 according to the present embodiment includes an IF unit 10, a handover processing unit 11, a lower layer processing unit 14, an upper layer processing unit 15, a master control unit 12, and a slave control unit 13. And a scheduling unit 16 and a data buffer unit 17.
  • the IF unit 10 is an interface for transmitting and receiving various signals to and from another eNB1.
  • the IF unit 10 in this embodiment corresponds to the X2 interface.
  • the handover processing unit 11 executes a handover process when receiving a handover request from the UE 2. Specifically, when the handover processing unit 11 receives a handover request from the UE 2, the handover processing unit 11 secures radio resources for communication with the UE 2 and enables communication with the UE 2.
  • the master control unit 12 performs processing related to determination of the master cell and change of the master cell.
  • the master control unit 12 includes a master cell determination unit 121, a master cell change unit 122, a power calculation unit 123, and a cell information management unit 124.
  • the master cell determination unit 121 determines the cell 5 in which the UE 2 is located as the master cell. Specifically, the master cell determination unit 121 registers the cell 5 where the UE 2 is located in the cell information management unit 124 described later as the master cell of the group cell 50 for the UE 2. Thereby, eNB1 which received the group cell construction request can judge that the own station is eNB1M.
  • the master cell determining unit 121 determines the cell 5 of its own station as the master cell
  • the master cell determining unit 121 transmits a slave cell determining request to the slave cell determining unit 131 described later.
  • the slave cell determination unit 131 performs determination processing of the slave cells included in the group cell 50. The slave cell determination process will be described later.
  • the master cell changing unit 122 changes the master cell when the communication quality between the UE 2 and the master cell deteriorates. Specifically, when the own station is the eNB 1S, the master cell changing unit 122 receives the pilot signal calculated by the power calculating unit 123 described later based on the pilot signal received from the UE 2 via the slave cell of the own station. Information on power (hereinafter referred to as “received power information”) is transmitted to the eNB 1M via the X2 interface.
  • the master cell changing unit 122 compares the received power indicated by the received power information received from each eNB 1S and the received power of the pilot signal received through the slave cell of the own station, A slave cell with high received power is determined. Subsequently, the master cell changing unit 122 compares the determined received power of the slave cell with the received power of the pilot signal received from the UE 2 via the master cell.
  • the master cell changing unit 122 changes the slave cell to a new master cell, Change the current master cell to a slave cell.
  • the master cell changing unit 122 instructs the cell information managing unit 124 described later to change the cell 5 to a master cell and change the current master cell to a slave cell.
  • the new master cell is the cell 5 formed by the current eNB 1M
  • the current eNB 1M continues to function as the eNB 1M.
  • the master cell changing unit 122 transmits a notification that the cell 5 should be a master cell (hereinafter, referred to as “master cell change notification”) to the other eNB 1 that forms the cell 5.
  • master cell change notification a notification that the cell 5 should be a master cell
  • the master cell changing unit 122 instructs the cell information managing unit 124 to change the current master cell to a slave cell.
  • the master cell change unit 122 when the master cell change unit 122 receives the master cell change notification from the eNB 1M when the own station is the eNB 1S, the master cell change unit 122 becomes a target of mastering with respect to the cell information management unit 124 based on the master cell change notification. Instruct to change cell 5 to master cell. Thereby, this eNB1S comes to function as eNB1M.
  • the master cell change notification includes information on each eNB 1 that constructs the group cell 50.
  • the master cell changing unit 122 notifies each eNB1S that constructs the group cell 50 that the own station has become eNB1M. Thereby, each eNB1S which constructs the group cell 50 can specify a new eNB1M.
  • the master cell changing unit 122 changes the slave cell to the master cell when the communication quality between the UE 2 and the master cell is higher. It functions as an example of reference changing means for changing a master cell formed by the own station to a slave cell.
  • the master cell changing unit 122 functions as an example of a reference changing unit, so that the highest received power among the received power represented by the received power information received from the eNB 1S forming the slave cell is When the received power of the pilot signal received from UE2 is higher, a request to change the slave cell to the master cell is sent to eNB 1S that forms the slave cell that has transmitted the received power information indicating the highest received power. At the same time, the master cell formed by the own station is changed to a slave cell.
  • the power calculator 123 calculates the received power of the pilot signal that is periodically transmitted from the UE2.
  • the power calculation by the power calculation unit 123 is performed for each cell 5 formed by the own station.
  • the power calculation part 123 transmits the received power information regarding the calculated received power to the eNB 1M via the X2 interface when the own station is the eNB 1S.
  • the power calculation part 123 transmits the received power information regarding the calculated received power to the master cell change part 122 and the slave cell change part 132, when a self-station is eNB1M.
  • the received power information transmitting unit transmits the received power information indicating the received power of the pilot signal to the eNB 1M that forms the master cell. It serves as an example.
  • the cell information management unit 124 displays information (hereinafter referred to as “cell management information”) indicating whether the cell 5 formed by the own station is a master cell, a slave cell, or a normal cell that is neither of them. It manages for every UE2. Thereby, each eNB1 can determine which cell 5 is the master cell and the slave cell among the cells 5 formed by the own station, and whether the own station is the eNB1M or the eNB1S. Judgment can be made. In addition, the cell information management unit 124 registers and updates cell management information in accordance with instructions from the master cell determination unit 121, the master cell change unit 122, the slave cell determination unit 131, or the slave cell change unit 132.
  • the slave control unit 13 performs processing related to determination of slave cells and reconstruction of slave cells. Specifically, the slave control unit 13 includes a slave cell determination unit 131 and a slave cell change unit 132.
  • the slave cell determination unit 131 determines a slave cell included in the group cell 50 based on the slave cell determination request received from the master cell determination unit 121.
  • the slave cell determination request includes information indicating which cell 5 of the own station is the master cell.
  • each eNB 1 stores in advance a position information of the cell 5 formed by the own station and the cell 5 formed by another eNB 1 in a predetermined storage area. Then, the slave cell determination unit 131 determines which cell 5 of the own station is the master cell based on the slave cell determination request, and the cell 5 adjacent to the master cell based on the information stored in the predetermined storage area. And the identified cell 5 is determined as a slave cell.
  • the slave cell determination unit 131 transmits, via the X2 interface, a slave request, which is a request that the corresponding cell 5 should be a slave cell, to the other eNB 1 that forms the determined slave cell. Then, when the local station is the eNB 1M, when the local cell 5 is determined as the slave cell, or when the slave cell determination unit 131 receives the slave request from the eNB 1M, the slave cell determination unit 131 sets the cell 5 as the slave cell.
  • the cell information management unit 124 is instructed to register.
  • the slave request includes information indicating which cell 5 is the master cell. Thereby, eNB1 which received the slave request
  • the slave cell determining unit 131 determines a slave cell included in the group cell 50 that is configured with the cell 5 formed by the local station as the master cell. It functions as an example of means.
  • the slave cell changing unit 132 changes the slave cell when the UE 2 is located at the end of the group cell 50. Specifically, the slave cell changing unit 132 of the eNB 1M first receives received power information corresponding to each slave cell from each eNB 1S via the X2 interface. Moreover, the slave cell change part 132 of eNB1M acquires the received power information corresponding to the master cell and slave cell of an own station from the electric power calculation part 123.
  • the slave cell changing unit 132 of the eNB 1M estimates the current position of the UE 2 based on the received power information. Specifically, the reception power of the pilot signal transmitted from the UE 2 basically increases as the distance from the UE 2 decreases and decreases as the distance from the UE 2 increases. Therefore, the slave cell changing unit 132 can estimate the current position of the UE 2 by comparing the received power corresponding to the master cell and each slave cell that configures the group cell 50.
  • the slave cell changing unit 132 of the eNB 1M adds and releases a slave cell that configures the group cell 50. Specifically, the slave cell changing unit 132 of the eNB 1M first identifies the cell 5 in which the UE 2 is located from the estimated position of the UE 2. Next, the slave cell changing unit 132 of the eNB 1M determines a cell 5 that is adjacent to the cell 5 and other than the slave cell that currently constructs the group cell 50 as a new slave cell.
  • the slave cell changing unit 132 of the eNB 1M transmits a slave request to the eNB 1 that forms the cell 5 determined as a new slave cell.
  • a slave request includes information for specifying the cell 5 to be slaved, information for specifying the eNB 1M, and the like.
  • the slave cell changing unit 132 of the eNB 1S when the slave cell changing unit 132 of the eNB 1S receives the slave request from the eNB 1M, the slave cell changing unit 132 instructs the cell information managing unit 124 to register the corresponding cell 5 as a slave cell.
  • the slave cell changing unit 132 of the eNB 1M instructs the cell information management unit 124 to register the cell 5 as the slave cell. Instruct.
  • the slave cell changing unit 132 releases the slave cells included in the current group cell 50 in order of increasing distance from the UE 2 according to the number of slave cells newly added to the group cell 50. Specifically, the slave cell changing unit 132 of the eNB 1M transmits a slave release notification to the eNB 1S that forms the slave cell to be released.
  • the cell information managing unit 124 changes the corresponding slave cell to a normal cell other than the cell 5 that configures the group cell 50. To instruct. Similarly, the slave cell change unit 132 of the eNB 1M instructs the cell information management unit 124 to change the cell 5 to a normal cell when the cell 5 to be released is the cell 5 formed by the own station. Instruct.
  • the slave cell changing unit 132 is an example of a dependent changing unit that changes the slave cell included in the group cell 50 based on the position of the UE 2 estimated from the received power represented by the received power information acquired from each eNB 1. Function.
  • the lower layer processing unit 14 is a processing unit that executes processing related to a MAC (Media Access Control) layer and a PHY (Physical Layer) layer.
  • the lower layer processing unit 14 has a function as an interface with the UE 2, identifies data (packets) received from the UE 2 via the radio link, and delivers the data to each processing unit, or is delivered from each processing unit. Data is transmitted to UE2 via a radio link.
  • the lower layer processing unit 14 performs radio resource allocation control for communication with the UE 2. Further, the lower layer processing unit 14 functions as a signal transmission unit, and periodically transmits a pilot signal to the UE 2 via a radio link.
  • the upper layer processing unit 15 is a processing unit that executes processing related to the PDCP (Packet Data Convergence Protocol) layer and the RLC (Radio Link Control) layer. For example, the upper layer processing unit 15 transmits / receives data to be transmitted to the UE 2 and various signals to / from the MME / UPE 3 via the S1 interface.
  • PDCP Packet Data Convergence Protocol
  • RLC Radio Link Control
  • the scheduling unit 16 performs control for synchronizing the operations of the lower layer processing unit 14 of the eNB 1M and the eNB 1S.
  • the scheduling unit 16 includes a lower layer control unit 161 and a feedback control unit 162.
  • the lower layer control unit 161 is a processing unit that controls the lower layer processing unit 14, and in particular, when the local station is the eNB 1M, determines radio resources and transmission power that can be commonly used in the group cell 50, Also, retransmission control is performed.
  • the feedback control unit 162 receives the received power information of the pilot signal received by the UE 2 via the master cell and the slave cell from the UE 2, the feedback control unit 162 uses the received power information as feedback information from the UE 2 to the lower layer control unit 161. Send.
  • the data buffer unit 17 performs control for simultaneously transmitting data to be transmitted to the UE 2 to the lower layer processing unit 14 of the eNB 1M and the eNB 1S.
  • the data buffer unit 17 includes a data transfer processing unit 171 and a data sharing management unit 172.
  • the data transfer processing unit 171 is a processing unit that delivers data from the upper layer processing unit 15 to the lower layer processing unit 14.
  • the data transfer processing unit 171 receives data from the upper layer processing unit 15 only when the own station is the eNB 1M, transmits the received data to the lower layer processing unit 14 of the own station, The data is transferred to the data transfer processing unit 171 of the eNB 1S.
  • the data sharing management unit 172 performs timing adjustment so that the data from the upper layer processing unit 15 is transmitted to the lower layer processing unit 14 of the eNB 1M and the lower layer processing unit 14 of the eNB 1S at the same time.
  • FIG. 5 is a diagram for explaining processing executed by the scheduling unit 16 and the data buffer unit 17.
  • the MME / UPE 3 corresponding to the host device of each eNB 1 transmits data to the UE 2 only to the eNB 1M in the group cell 50 for the UE 2. Then, the upper layer processing unit 15 of the eNB 1M performs various processes on the data received from the MME / UPE 3, and transfers the data as RLC-PDU (RLC Protocol Data Unit) obtained by dividing the data into predetermined protocol data units. Transmit to the processing unit 171.
  • RLC-PDU RLC Protocol Data Unit
  • the upper layer processing unit 15 functions as an example of an upper layer processing unit that receives data to be transmitted to the UE 2 from the MME / UPE 3, performs a predetermined process on the received data, and transmits the data.
  • the data transfer processing unit 171 of the eNB 1 M transmits to the data sharing management unit 172 as a data arrival notification that the RLC-PDU has been received.
  • the data sharing management unit 172 determines the transmission timing of the RLC-PDU to the lower layer processing unit 14, and notifies the data transfer processing unit 171 of the determined transmission timing as transmission timing information. .
  • the data transfer processing unit 171 that has received the transmission timing information converts the RLC-PDU into a MAC-SDU (MAC Service Data Unit), and then transfers the MAC-SDU together with the transmission timing information to the data transfer processing unit 171 of the eNB 1S. . Then, the data transfer processing unit 171 of the eNB 1M and the data transfer processing unit 171 of the eNB 1S store the MAC-SDUs in the predetermined data transfer processing units 171 until the MAC-SDU transmission timing is reached. Buffer it in the storage area. Then, when the timing for transmitting the MAC-SDU arrives, the data transfer processing unit 171 of the eNB 1M and the data transfer processing unit 171 of the eNB 1S transmit the MAC-SDU to each lower layer processing unit 14.
  • MAC-SDU MAC Service Data Unit
  • the data sharing management unit 172 functions as an example of a transmission timing determination unit that determines a timing when data received from the upper layer processing unit 15 is transmitted to the lower layer processing unit 14.
  • the data transfer processing unit 171 functions as an example of a data transfer unit that transfers the data received from the upper layer processing unit 15 and the information related to the transmission timing determined by the data sharing management unit 172 to the eNB 1S forming the slave cell. . Further, the data transfer processing unit 171 receives the data when the data transmission timing determined by the data sharing management unit 172 or the data transmission timing received from the eNB 1M forming the master cell has arrived.
  • 14 functions as an example of a data transmission unit that transmits data to 14.
  • the lower layer control unit 161 of the eNB 1M is a radio resource for communication with the UE 2, and determines a radio resource to be commonly allocated to each eNB 1S and the own station.
  • the lower layer control unit 161 of the eNB 1M transmits the lower layer information of the eNB 1S to the eNB 1S. Request. Subsequently, the lower layer control unit 161 of the eNB 1M and the lower layer control unit 161 of the eNB 1S that has received the request acquire each lower layer information from the lower layer processing unit 14.
  • the lower layer information includes information (resource allocation status information) related to radio resources allocated to each UE 2 located in the own station.
  • the lower layer control unit 161 of the eNB 1S acquires the resource allocation status information included in the lower layer information from the lower layer processing unit 14
  • the acquired resource allocation status information is sent to the lower layer control unit 161 of the eNB 1M via the X2 interface.
  • the lower layer processing unit 14 and the lower layer control unit 161 function as an example of a resource allocation status information transmission unit that transmits information on the available radio resources of the local station as resource allocation status information to the eNB 1M that forms the master cell. .
  • the lower layer control unit 161 of the eNB 1M can use the transmission power common in the group cell 50 and the common use in the group cell 50 based on the resource allocation situation information of the own station and the resource allocation situation information received from the eNB 1S. Calculate radio resources. Specifically, the lower layer control unit 161 of the eNB 1M specifies a free radio resource common to the local station and the eNB 1S based on the resource allocation status information of the local station and the resource allocation status information received from the eNB 1S. And the lower layer control part 161 of eNB1M determines this radio
  • the lower layer control unit 161 of the eNB 1M calculates radio resources and transmission power that are common in the group cell 50 in consideration of the feedback information.
  • the lower layer control unit 161 of the eNB 1M transmits information on the determined radio resource (hereinafter referred to as “radio resource information”) and information on the determined transmission power (hereinafter referred to as “transmission power information”) of the eNB 1S. It transmits to the lower layer control part 161. Then, the lower layer control unit 161 of the eNB 1M and the lower layer control unit 161 of the eNB 1S transmit the determined radio resource information and transmission power information to each lower layer processing unit 14.
  • the lower layer control unit 161 functions as an example of a common resource determination unit, is a radio resource for communication with the UE 2, and forms the slave cell determined by the slave cell determination unit 131 and the eNB 1S and A radio resource to be allocated in common to the own station is determined. Further, the lower layer control unit 161 functions as an example of a radio resource information transmitting unit, and transmits information on the determined radio resource to the eNB 1S that forms the slave cell.
  • the lower layer processing unit 14 of the eNB 1M and the eNB 1S reserves a radio resource corresponding to the received radio resource information as a radio resource for communication with the UE 2. Then, the lower layer processing unit 14 of the eNB 1M and the eNB 1S transmits the data (MAC-SDU) to the UE 2 received from the data transfer processing unit 171 via the radio link to the UE 2 with transmission power based on the received transmission power information. Send.
  • MAC-SDU data
  • each eNB 1 that constructs the group cell 50 transmits transmission data to the UE 2 at the same time using radio resources common in the group cell 50. Thereby, even if UE2 moves from cell 5 in the area to another cell 5 because UE2 has already transmitted the data to UE2 to destination cell 5, handover processing is performed. You can move without doing.
  • the data transfer processing unit 171 and the data sharing management unit 172 are divided into the upper layer processing unit 15 corresponding to the PDCP layer and the RLC layer, and the lower layer corresponding to the MAC layer and the PHY layer. It is provided as an intermediate layer with the processing unit 14.
  • the group cell 50 can be constructed without changing the operations of the lower layer processing unit 14 and the upper layer processing unit 15. That is, the data transfer processing unit 171 and the data sharing management unit 172 align the timing at which the data for the UE 2 reaches the lower layer processing unit 14 of the eNB 1M and each eNB 1S, so that the upper layer processing unit 15 and the lower layer processing unit 14
  • the construction of the group cell 50 can be realized without changing the process.
  • FIG. 6 is a block diagram illustrating the configuration of the UE according to the present embodiment.
  • the UE 2 according to the present embodiment includes an IF unit 20, a handover processing unit 21, an operation input unit 22, a signal transmission unit 23, and a power calculation unit 24.
  • the handover processing unit 21 transmits a handover request and executes a handover process with the eNB 1 when moving from the cell 5 being located to another cell 5. Note that when a group cell construction request operation is performed by an operation input unit 22 (to be described later), the handover processing unit 21 receives a handover request even when moving from the cell 5 in the service area to another cell 5. Do not send.
  • the operation input unit 22 corresponds to an example of an input unit, and receives an input operation from the user of the UE 2.
  • the operation input unit 22 accepts a group cell construction request operation for requesting construction of the group cell 50 from the user.
  • the group cell construction request operation includes, for example, an operation of starting an application that requires construction of the group cell 50 in addition to an operation of a user pressing a predetermined button provided in the UE 2.
  • the application that requires the construction of the group cell 50 is, for example, an application that requires more reliable communication with the eNB 1.
  • the signal transmission unit 23 performs transmission processing of various signals to the eNB 1.
  • the signal transmission unit 23 functions as an example of a group cell construction request transmission unit, and when the operation input unit 22 receives a group cell construction request operation from a user, the cell in which the own station is located A group cell construction request is transmitted to eNB1 forming 5.
  • the signal transmission part 23 transmits a predetermined pilot signal regularly with respect to each eNB1.
  • the group cell construction request may be a dedicated signal, or may be transmitted by being included in other signals such as broadcast information.
  • the power calculator 24 calculates the received power of the pilot signal that is periodically transmitted from each eNB 1 through the cell 5. Moreover, the power calculation unit 24 transmits the received power information of the pilot signal to the eNB 1M of the group cell 50 constructed for the own station.
  • FIG. 7 is a sequence diagram illustrating an example of a processing procedure of a handover process in the mobile communication system S of the present embodiment.
  • UE2a located in the cell 5a which eNB1a forms moves to the cell 5f which eNB1b forms
  • the handover process performed between UE2a, eNB1a, and eNB1b is demonstrated.
  • the handover processing unit 21 of the UE 2a transmits a handover request to the eNB 1b via the eNB 1a (Ste S101).
  • the handover request includes, for example, identification information of the cell 5f formed by the eNB 1b that is the destination of the UE 2a, information about the UE 2a, and the like as information necessary when the eNB 1b executes the handover process.
  • the handover processing unit 11 of the eNB 1b that has received the handover request determines whether or not the UE 2a can be accepted (step S102). If the handover processing unit 11 of the eNB 1b determines that the UE 2a can be accepted, the handover processing unit 11 secures radio resources used for radio communication with the UE 2a (step S103), and transmits a handover request response signal to the eNB 1a (step S104). .
  • the handover processing unit 11 of the eNB 1a transmits a handover instruction signal to the UE 2a (Step S105).
  • the handover instruction signal includes information on radio resources used by the UE 2a for radio communication with the eNB 1b.
  • the handover processing unit 21 of the UE 2a When receiving the handover instruction signal, the handover processing unit 21 of the UE 2a secures radio resources according to the radio resource information included in the handover instruction signal and enables communication with the eNB 1b (step S106). Thereafter, the UE 21a transmits / receives a synchronization establishment signal, timing information, etc. in order to establish frame synchronization and time alignment adjustment with the eNB 1b, and when normal communication is possible, the handover completion signal to the eNB 1b. Is transmitted (step S107).
  • the handover processing unit 21 of the eNB 1b that has received the handover completion signal transmits a radio resource release instruction signal to the eNB 1a (step S108), and the eNB 1a handover processing unit 21 receives the radio resource release instruction signal. Based on this, radio resources are released (step S109). Thereby, the handover process is completed, and the UE 2a can continue the wireless communication with the eNB 1b.
  • FIG. 8 is a flowchart illustrating an outline of a processing procedure of the eNB 1M according to the present embodiment.
  • the eNB 1M first determines a master cell (step S201). Specifically, when the master cell determination unit 121 of the eNB 1M receives the group cell construction request from the UE 2, the cell 5 in which the UE 2 is located is determined as a master cell, and a cell information management unit that the cell 5 is the master cell 124.
  • the eNB 1M determines a slave cell (step S202). Specifically, the slave cell determination unit 131 of the eNB 1M specifies the cell 5 adjacent to the master cell based on the position information of the cell 5 formed by another eNB 1 stored in a predetermined storage area. Then, the eNB 1M performs radio resource sharing, retransmission control, data transfer, and data sharing management so that the slave cell determined in step S202 is subordinate to the master cell determined in step S201 (step S203).
  • the slave control unit 13 of the eNB 1M determines whether or not the UE 2 is located at the end of the group cell (Step S204). Specifically, this determination is performed by estimating the position of the UE 2 based on the received power of the pilot signal from the UE 2 calculated by the power calculation unit 123 of the eNB 1M and the power calculation unit 123 of the eNB 1S.
  • the slave cell changing unit 132 of the eNB 1M reconstructs the slave cell (Step S205). Specifically, the slave cell changing unit 132 of the eNB 1M specifies the cell 5 where the UE 2 is located from the estimated position of the UE 2, and is the cell 5 adjacent to the cell 5 and is the current slave cell. The cell 5 that has not been determined is determined as a new slave cell. In addition, the slave cell changing unit 132 of the eNB 1M releases the slave cells in order of increasing distance from the UE 2 according to the number of newly added slave cells. When the process of step S205 is completed, the eNB 1M shifts the process to step S203, and performs processes such as radio resource sharing and retransmission control again.
  • the master control unit 12 of the eNB1M determines whether or not the communication quality between the UE2 and the master cell is good (Step S204). S206). Specifically, the master cell changing unit 122 of the eNB 1M receives the pilot received via the slave cell based on the received power of the pilot signal from the UE 2 calculated by the power calculating unit 123 of the eNB 1M and the power calculating unit 123 of the eNB 1S. It is determined whether the received power of the signal is higher than the received power of the pilot signal received via the master cell.
  • step S207 when the communication quality between the UE 2 and the master cell is not good (No at Step S206), that is, the reception power of the pilot signal received via the slave cell is received by the pilot signal received via the master cell.
  • the master cell changing unit 122 of the eNB 1M changes the master cell (step S207).
  • step S207 When the process of step S207 is completed, or when it is determined in step S206 that the communication quality between the UE 2 and the master cell is good (Yes in step S206), the eNB 1M moves the process to step S203 and shares the radio resource. And processing such as retransmission control again.
  • FIG. 9 is a sequence diagram illustrating an example of a processing procedure of master cell determination processing according to the present embodiment.
  • the operation input unit 22 of the UE 2 acquires a group cell construction request operation from the user of the own station (step S301)
  • the operation input unit 22 notifies the signal transmission unit 23 that the group cell construction request operation has been acquired.
  • the signal transmission unit 23 that has received such notification transmits a group cell construction request to the eNB1 that forms the UE2 serving cell via the cell currently serving (UE2 serving cell) ( Step S302).
  • This group cell construction request includes identification information for identifying UE2.
  • the master cell determination unit 121 of the eNB 1 that has received the group cell construction request via the UE 2 serving cell registers the UE 2 serving cell as a master cell in the cell information management unit 124 (step S303).
  • UE2 serving cell becomes a master cell of group cell 50 constructed for UE2, and eNB1 forming the UE2 serving cell uses eNB1M as a process for constructing or changing group cell or transmitting data to UE2. Execute.
  • a group cell construction request is transmitted to the eNB1, and the group cell 50 Is built. That is, since the user can construct the group cell 50 only when reliable communication is necessary, for example, the communication cost can be prevented from becoming higher than necessary.
  • FIG. 10 is a sequence diagram illustrating an example of the processing procedure of the slave cell determination processing according to the present embodiment. The process shown in FIG. 10 is continued from the master cell determination process shown in FIG.
  • the master cell determination unit 121 of the eNB 1M transmits a slave cell determination request to the slave cell determination unit 131 of the local station (step S401).
  • the slave cell determination request includes information indicating which cell 5 is the master cell.
  • each eNB 1 stores in advance a position information of the cell 5 formed by the own station and the cell 5 formed by another eNB 1 in a predetermined storage area. Then, the slave cell determination unit 131 of the eNB 1M determines which cell 5 is the master cell based on the slave cell determination request, and identifies the cell 5 adjacent to the master cell based on the information stored in the predetermined storage area Thus, a slave cell is determined (step S402).
  • the slave cell determining unit 131 of the eNB 1M transmits a slave request via the X2 interface to the other eNB 1 that forms the determined slave cell (step S403).
  • the slave cell determination unit 131 of the eNB 1M instructs the cell information management unit 124 of the own station to register the cell 5 as a slave cell. (Step S404).
  • the eNB 1 that has received the slave request from the eNB 1M instructs the cell information management unit 124 of the local station to register the target cell 5 of the local station as a slave cell based on the slave request (step S405).
  • the slave request includes information indicating which cell 5 is the master cell.
  • requirement can identify which eNB1 is eNB1M.
  • Such information is stored in a predetermined storage area of the eNB 1.
  • the slave cell to be included in the group cell 50 is determined, and the eNB 1 that has received the slave request executes, as eNB 1S, processing related to the construction or change of the group cell or data transmission to the UE 2.
  • FIG. 11 is a sequence diagram illustrating an example of a processing procedure of data transfer processing and data sharing management processing according to the present embodiment.
  • the upper layer processing unit 15 of the eNB 1M performs various processes on the data received from the MME / UPE 3, and performs data transfer processing as RLC-PDU obtained by dividing the data into predetermined protocol data units. It transmits to the part 171 (step S501). Subsequently, when the data transfer processing unit 171 of the eNB 1M receives the RLC-PDU from the higher layer processing unit 15, the data transfer processing unit 171 transmits to the data sharing management unit 172 as a data arrival notification that the RLC-PDU has been received (step S502). .
  • the data sharing management unit 172 determines the transmission timing of the RLC-PDU to the lower layer processing unit 14 (step S503), and uses the information regarding the determined transmission timing as transmission timing information. 171 is notified (step S504). Subsequently, after receiving the transmission timing information, the data transfer processing unit 171 converts the RLC-PDU into the MAC-SDU, and then adds the transmission timing information to the converted MAC-SDU (step S505), and the data transfer of the eNB 1S The data is transferred to the processing unit 171 (step S506).
  • the data transfer processing unit 171 of the eNB 1M and the data transfer processing unit 171 of the eNB 1S store the MAC-SDUs in the predetermined data transfer processing units 171 until the MAC-SDU transmission timing is reached. Buffer it in the storage area. Thereafter, when the timing for transmitting the MAC-SDU has arrived based on the transmission timing information (step S507), the data transfer processing unit 171 of the eNB 1M transmits the MAC-SDU to each lower layer processing unit 14 (step S507). S508).
  • the data transfer processing unit 171 of the eNB 1S transmits the MAC-SDU to each lower layer processing unit 14 ( Step S510).
  • FIG. 12 is a sequence diagram illustrating an example of a processing procedure of the radio resource sharing process and the retransmission control process according to the present embodiment.
  • the feedback control unit 162 of the eNB 1M makes a retransmission request to the lower layer control unit 161 (step S602).
  • the feedback information is a reception result of the uplink signal of UE2.
  • the lower layer control unit 161 of the eNB 1M acquires the resource allocation status information included in the lower layer information of the own station from the lower layer processing unit 14 (step S603).
  • the lower layer control unit 161 of the eNB 1S requested to transmit the lower layer information from the eNB 1M acquires the resource allocation status information included in the lower layer information from the lower layer processing unit 14 (step S604), and the eNB 1M Transfer to the lower layer control unit 161 via the X2 interface (step S605).
  • the lower layer control unit 161 of the eNB 1M calculates radio resources that can be commonly used in the group cell 50 based on the resource allocation status information of the own station and the resource allocation status information received from the eNB 1S (step S606). . Specifically, the lower layer control unit 161 of the eNB 1M specifies a free radio resource common to the local station and the eNB 1S based on the resource allocation status information of the local station and the resource allocation status information received from the eNB 1S. And the lower layer control part 161 of eNB1M determines the specified radio
  • the lower layer control unit 161 of the eNB 1M transmits radio resource information, which is information regarding the determined radio resource, to the lower layer processing unit 14 of the own station (step S607). Further, the lower layer control unit 161 of the eNB 1M transfers the radio resource information to the lower layer control unit 161 of the eNB 1S via the X2 interface (Step S608). And the lower layer control part 161 of eNB1M which received radio
  • the lower layer processing unit 14 of the eNB 1M secures a radio resource corresponding to the received radio resource information as a radio resource for communication with the UE 2 (Step S610).
  • the lower layer processing unit 14 of the eNB 1S reserves a radio resource corresponding to the received radio resource information as a radio resource for communication with the UE 2 (Step S611).
  • the transmission data to UE2 are simultaneously transmitted from eNB1M and eNB1S using the radio
  • FIG. As a result, even if UE2 moves from cell 5 in the area to another cell 5 since UE2 has already transmitted data to UE2 to destination cell 5, handover processing is performed. You can move without doing.
  • FIG. 13A is a sequence diagram illustrating an example of a processing procedure of a master cell change process when the new master cell is a cell formed by the eNB 1M.
  • UE2 periodically transmits a pilot signal to each eNB1 (step S701). Subsequently, the master control unit 12 of the eNB 1M calculates the received power of the pilot signal received via the master cell by the power calculation unit 123 (step S702). Similarly, the master control unit 12 of the eNB 1M uses the power calculation unit 123 to calculate the received power of the pilot signal received via the slave cell (step S703). In addition, the master control unit 12 of the eNB 1S calculates the received power of the pilot signal received via the slave cell by the power calculation unit 123 (step S704). Then, the master control unit 12 of the eNB 1S transfers the received power information that is the calculation result to the master control unit 12 of the eNB 1M via the X2 interface (Step S705).
  • the master cell changing unit 122 of the eNB 1M compares the received power indicated by the received power information received from each eNB 1S with the received power of the pilot signal received via the slave cell of the own station, and selects a new master cell. (Step S706). Specifically, the master cell changing unit 122 of the eNB 1M determines a slave cell with the highest received power based on each received power information. Subsequently, the master cell changing unit 122 of the eNB 1M compares the received power of the slave cell with the highest received power with the received power of the pilot signal received from the UE 2 via the master cell. If the received power of the slave cell is higher than the received power of the master cell, the master cell changing unit 122 of the eNB 1M determines that the slave cell is a new master cell and the current master cell is a slave cell.
  • the cell information management unit 124 is instructed to change the slave cell having the highest pilot signal to the master cell and to change the current master cell to the slave cell. (Step S707).
  • the current master cell is changed to a slave cell (slave), and the current slave cell having the highest pilot signal becomes a new master cell (master).
  • the current eNB 1M continues to function as the eNB 1M.
  • FIG. 13-2 is a sequence diagram illustrating an example of a processing procedure of a master cell change process when the new master cell is a cell other than the cell formed by the eNB 1M. Note that the processing from Steps S751 to S755 shown in FIG. 13-2 is the same as the processing from Steps S701 to S705 shown in FIG.
  • step S756 of FIG. 13-2 when the cell 5 with the highest pilot signal reception power is a slave cell formed by the eNB 1S, the master cell changing unit 122 of the eNB 1M sets the cell 5 as a master cell to the eNB 1S. A master cell change notification to the effect is transmitted (step S757). Also, the master cell changing unit 122 of the eNB 1M instructs the cell information managing unit 124 to change the current master cell to a slave cell (step S758).
  • the master cell changing unit 122 of the eNB 1S instructs the cell information managing unit 124 to change the master cell to the master cell based on the master cell change notification ( Step S759).
  • this eNB1S comes to function as eNB1M.
  • the master cell change notification includes information for specifying each eNB 1S that constructs the group cell 50.
  • the master cell change part 122 notifies each eNB1S which constructs the group cell 50 that the own station became eNB1M. Thereby, each eNB1S which constructs the group cell 50 can specify a new eNB1M.
  • the communication quality between the UE2 and the master cell deteriorates, that is, the communication quality between the UE2 and the slave cell becomes higher than the communication quality between the UE2 and the master cell. If so, change the master cell. Thereby, even if UE2 moves in the group cell 50 after the construction of the group cell 50, it can perform radio communication with the cell 5 having the highest communication quality in the group cell 50.
  • FIG. 14 is a sequence diagram illustrating an example of the processing procedure of the slave cell change processing according to the present embodiment.
  • UE2 regularly transmits a pilot signal to each eNB1 (step S801). Subsequently, the master control unit 12 of the eNB 1M calculates the reception power of the pilot signal received via the master cell by the power calculation unit 123 (step S802), and transmits the received power information that is the calculation result to the slave cell change unit 132. (Step S803). Similarly, the master control unit 12 of the eNB 1M calculates the received power of the pilot signal received via the slave cell by the power calculation unit 123 (step S804), and the received power information as the calculation result to the slave cell change unit 132. Transmit (step S805).
  • the master control unit 12 of the eNB 1 calculates the received power of the pilot signal received via the cell 5 by the power calculation unit 123 (step S806), and the received power information as the calculation result is sent to the slave control unit 13 of the eNB 1M. The transfer is performed via the X2 interface (step S807).
  • the slave cell changing unit 132 of the eNB 1M estimates the current position of the UE 2 based on the received power information received from the master control unit 12 of the own station or another eNB 1. Subsequently, when the position of the UE 2 estimated based on the reception power corresponding to the master cell and each slave cell is near the end of the group cell 50, the slave cell changing unit 132 of the eNB 1M selects the slave cell that configures the group cell 50. It is determined again (step S808). Specifically, the slave cell changing unit 132 of the eNB 1M specifies the cell 5 in which the UE 2 is located from the estimated position of the UE 2, and is the cell 5 adjacent to the cell 5, and the current group cell 50 is changed.
  • Cells 5 other than the slave cell to be constructed are determined as new slave cells. Then, the slave cell changing unit 132 of the eNB 1M transmits a slave request to the eNB 1 that forms the cell 5 determined as a new slave cell (step S809).
  • the slave information changing unit 132 changes the slave cell that is the release target to the cell in the cell information management unit.
  • An instruction is given (step S810).
  • the slave cell changing unit 132 of the eNB 1 receives the slave request from the eNB 1M, the slave cell changing unit 132 instructs the cell information management unit 124 to register the cell 5 that is the subject of slave formation as a slave cell (step S811).
  • the UE 2 when the UE 2 is located at the end of the group cell 50, the UE 2 moves out of the group cell 50 by changing the slave cell included in the group cell 50. Can be prevented in advance.
  • the radio resource for communication with the UE 2 is shared between the plurality of cells 5 that configure the group cell 50, and the radio resource shared by the eNB 1M and the eNB 1S is used to transmit the UE 2 Send data to all at once. That is, by setting the cell 5 where the UE 2 is not located in a state in which the handover process has been completed, even if the UE 2 has moved to the cell 5, the UE 2 and the destination can be moved without performing the handover process. Wireless communication can be continued with the eNB1. As a result, even when the UE 2 frequently moves to another cell 5 in the group cell 50, it is possible to prevent communication quality degradation and communication interruption caused by the handover process. .
  • the UE 2 can move between the cells 5 without performing the handover process by reconstructing the group cell 50 according to the position of the UE 2 so that the UE 2 does not move outside the group cell 50. The state can be maintained.
  • the slave cell having the highest communication quality with the UE2 is set as a new master cell.
  • the UE 2 can perform wireless communication with the cell 5 having the highest communication quality in the group cell 50 even if the UE 2 moves within the group cell 50 after the group cell 50 is constructed.
  • UE2 when UE2 is located at the end of group cell 50, UE2 can be prevented from moving out of group cell 50 by changing the slave cell included in group cell 50. be able to.
  • a cell 5 other than the cell 5 that configures the group cell 50 and adjacent to the cell 5 where the UE 2 is located is determined as a new slave cell to be added to the group cell 50. That is, by adding the cell 5 having a high possibility that the UE 2 moves to the group cell 50 as a new slave cell, it is possible to more reliably prevent the occurrence of the handover process accompanying the movement of the UE 2 between the cells 5.
  • the processing for the reconstruction of the group cell 50 can be distributed.
  • the mobile communication system, the base station, the mobile station, and the wireless communication method disclosed in this case may be implemented in various different forms other than the above-described embodiments. Therefore, in the second embodiment, another embodiment of the mobile communication system, the base station, the mobile station, and the wireless communication method disclosed in this case will be described.
  • symbol is attached
  • the group cell construction request is transmitted when a predetermined button is pressed by the user or when an application that needs to construct the group cell 50 is activated. It may be sent automatically.
  • FIG. 15 is a sequence diagram illustrating a processing procedure of master cell determination processing when a group cell construction request is automatically transmitted.
  • the eNB 1 periodically transmits notification information including information such as the state of the cell 5 of the own station to the UE 2 located in the cell 5 formed by the own station by the lower layer processing unit 14.
  • the lower layer processing unit 14 adds information (group cell constructable information) indicating that the own station is an eNB 1 capable of constructing the group cell 50 to the broadcast information, and then sends it to the UE 2.
  • the lower layer processing unit 14 functions as an example of a group cell constructable information transmitting unit that transmits group cell constructable information indicating that the local station is an eNB capable of constructing a group cell to the UE 2. To do.
  • the UE 2 determines whether or not the eNB 1 forming the cell 5 in the service area can construct the group cell 50 by using the signal transmission unit 23 (step S902). That is, the UE 2 determines whether the broadcast information received from the eNB 1 includes information indicating that the eNB 1 is an eNB 1 having a function of constructing the group cell 50. And when the information which shows that this eNB1 is eNB1 which has the function to construct
  • the UE 2 when the UE 2 is located in the cell 5 of the eNB 1 capable of constructing the group cell 50, the UE 2 automatically transmits a group cell construction request to the eNB 1, and therefore, based on a predetermined operation from the user. Compared with the case of transmitting a group cell construction request, the group cell 50 can be constructed more quickly. Such automatic transmission of the group cell construction request is particularly effective when the UE 2 is moving at high speed.
  • FIG. 16 is a block diagram illustrating a configuration of the UE 2 according to another embodiment.
  • the UE 2 in this case includes a master cell change determination unit 25 in addition to the IF unit 20, the handover processing unit 21, the operation input unit 22, the signal transmission unit 23, and the power calculation unit 24.
  • the master cell change determination unit 25 determines whether or not to change the master cell based on the calculation result of the received power of the pilot signal by the power calculation unit 24. Specifically, the master cell change determination unit 25 first acquires the received power information of the pilot signal transmitted from the eNB 1M and the eNB 1S via the master cell and the slave cell from the power calculation unit 24.
  • the master cell change determination unit 25 sends a master change notification (corresponding to a reference change request) to the eNB 1M that the slave cell should be changed to a new master cell. It transmits to the master control part 12 via a master cell.
  • FIG. 17A is a sequence diagram illustrating another example of the processing procedure of the master cell change process when the new master cell is a cell formed by the eNB 1M.
  • eNB1M and eNB1S periodically transmit pilot signals to UE2 (step S1001). Subsequently, the power calculation unit 24 of the UE 2 calculates the reception power of the pilot signal received via the master cell and the slave cell (step S1002).
  • Step S1003 when the master cell change determination unit 25 of the UE 2 acquires the received power information of the pilot signal received via the master cell and the slave cell from the power calculation unit 24, the received power information is compared and a new master cell is selected.
  • the master cell change determination unit 25 determines the slave cell as a new master cell. .
  • the master cell change determination unit 25 transmits a master change notification indicating that the slave cell should be changed to a new master cell to the master control unit 12 of the eNB 1M via the master cell (step S1004).
  • the master cell changing unit 122 of the eNB 1M receives the master change notification from the UE 2 via the radio link.
  • the master cell change determination unit 25 compares the received power of the pilot signals received from the eNB 1M and the eNB 1S, and the highest received power among the received powers of the pilot signals received via the slave cell is transmitted via the master cell.
  • a reference change request transmitting means for transmitting to the eNB 1M a reference change request indicating that the slave cell to which the pilot signal indicating the highest received power is transmitted should be changed to a master cell. It serves as an example.
  • the master cell changing unit 122 of the eNB 1M sets the slave cell to be mastered as the master cell, and changes the current master cell to the slave cell. 124 is instructed (step S1005).
  • FIG. 17-2 is a sequence diagram illustrating another example of the processing procedure of the master cell change process when the new master cell is a cell other than the cell formed by the eNB 1M. Note that the processing from steps S1051 to S1054 shown in FIG. 17-2 is the same as the processing from steps S1001 to S1004 shown in FIG.
  • the master cell changing unit 122 of the eNB 1M sets the cell 5 as the master cell to the eNB 1S.
  • a master cell change notification to the effect is transmitted (step S1055).
  • the master cell changing unit 122 of the eNB 1M instructs the cell information managing unit 124 to change the current master cell to a slave cell (step S1056).
  • the master cell changing unit 122 of the eNB 1S instructs the cell information managing unit 124 to change the master cell to the master cell based on the master cell change notification ( Step S1057).
  • this eNB1S comes to function as eNB1M.
  • the master cell changing unit 122 receives the master change notification from the UE 2
  • the master cell changing unit 122 changes the slave cell to which the pilot signal indicating the highest received power is transmitted to a new master cell based on the master change notification.
  • the master cell formed by the own station is changed to a slave cell.
  • the load on the master cell changing unit 122 of the eNB 1M can be reduced.
  • FIG. 18 is a block diagram illustrating a configuration of the UE 2 according to another embodiment.
  • the UE 2 in this case includes a slave cell change determination unit 26 in addition to the IF unit 20, the handover processing unit 21, the operation input unit 22, the signal transmission unit 23, and the power calculation unit 24.
  • the slave cell change determination unit 26 determines whether or not to change the slave cell based on the calculation result of the received power of the pilot signal by the power calculation unit 24. Specifically, the slave cell change determination unit 26 first acquires the received power information of the pilot signal transmitted from the eNB 1M and the eNB 1S via the master cell and the slave cell from the power calculation unit 24. Subsequently, the slave cell change determination unit 26 compares the acquired pieces of received power information and estimates the position of the own station.
  • the slave cell change determination unit 26 determines a slave cell to be added to the group cell 50 and a slave cell to be released. Specifically, the slave cell change determination unit 26 determines a cell 5 that is adjacent to the cell 5 in which the station is located and other than the slave cell that currently constructs the group cell 50 as a new slave cell. To do. The slave cell change determination unit 26 determines a slave cell to be released from the group cell 50 according to the number of cells 5 newly added to the group cell 50. Then, the slave cell change determination unit 26 transmits a slave request (corresponding to a dependent change request) to the slave control unit 13 of the eNB 1M via the master cell.
  • the slave cell change determination unit 26 becomes a slave indicating that the slave cell included in the group cell should be changed based on the position of the local station estimated from the received power represented by the received power information acquired from each eNB1. It functions as an example of a dependent change request transmission unit that transmits a request to the eNB 1M.
  • the slave request includes information for specifying a slave cell newly added to the group cell 50 and information for specifying a slave cell released from the group cell 50.
  • UE2 can identify eNB1M and eNB1S by acquiring the information regarding eNB1M and eNB1S which construct the group cell 50 from eNB1M regularly.
  • FIG. 19 is a sequence diagram illustrating another example of the processing procedure of the slave cell change process.
  • eNB1M and eNB1S periodically transmit pilot signals to UE2 (step S1101). Subsequently, the power calculation unit 24 of the UE 2 calculates the reception power of the pilot signal received via the master cell and the slave cell (step S1102).
  • the slave cell change determination unit 26 of the UE 2 acquires the received power information of the pilot signal received via the master cell and the slave cell from the power calculation unit 24, the slave cell change determination unit 26 estimates the position of the own station based on the received power information. Then, the slave cell is determined again (step S1103). Then, a slave reconfiguration notification including information for specifying a slave cell to be added to the group cell 50 and information for specifying a slave cell to be released from the group cell 50 is transmitted to the slave cell changing unit 132 of the eNB 1M via the master cell ( Step S1104).
  • the slave cell changing unit 132 of the eNB 1M that has received the slave reconfiguration notification transmits a slave request to the eNB 1 that forms the cell 5 that is the target of the slave (step S1105). Further, when the slave cell to be released from the group cell 50 is the cell 5 formed by the own station, the slave cell changing unit 132 of the eNB 1M changes the cell information managing unit to change the slave cell to a normal cell. 124 is instructed (step S1106).
  • the slave cell changing unit 132 of the eNB 1 that has received the slave request from the eNB 1M via the X2 interface registers the cell 5 to be slaved in the cell information management unit 124 as a slave cell (step S1107).
  • the slave cell changing unit 132 functions as an example of a slave changing unit, and when receiving a slave request from the UE 2, changes the slave cell included in the group cell 50 based on the slave request.
  • the load on the eNB 1M can be reduced.
  • FIG. 20 is a sequence diagram illustrating an example of a processing procedure of a slave cell determination process when a slave cell is determined based on cell position coordinate information received from each eNB1.
  • the eNB 1 installed in the vicinity of the eNB 1M transmits cell position coordinate information indicating the position coordinates of the cell formed by the own station to the eNB 1M via the X2 interface (step S1201).
  • the cell position coordinate information is input as a parameter unique to each eNB1. That is, the cell position coordinate information includes information related to the cell position coordinates and information for specifying the cell 5 corresponding to the cell position coordinates.
  • the eNB 1 installed in the vicinity of the eNB 1M transmits the cell position coordinate information when receiving a request from the eNB 1M to transmit the cell position coordinate information.
  • the slave cell determination unit 131 of the eNB 1M determines a slave cell based on the cell position coordinate information received from the neighboring eNB 1 (step S1202). Specifically, the slave cell determination unit 131 of the eNB 1M calculates the distance from the master cell to each cell 5 based on the received cell position coordinate information, selects a predetermined number of cells 5 that are close to the master cell, The selected cell 5 is determined as a slave cell.
  • the slave cell determination unit 131 of the eNB 1M transmits a slave request to the eNB 1 that forms the slave cell determined in step S1202 (step S1203).
  • the slave cell determination unit 131 of the eNB 1M registers the determined cell as a slave cell in the cell information management unit (step S1204).
  • the slave request includes information indicating which cell 5 should be slaved.
  • the slave cell determination unit 131 of the eNB 1 that has received the slave request via the X2 interface registers the cell 5 to be slaved in the cell information management unit 124 as a slave cell (step S1205).
  • the cell 5 of the eNB 1M and the cell 5 of the eNB 1 that are the slaves become slaves, and the eNB 1 that has received the slave notification functions as the eNB 1S.
  • the slave cell determination unit 131 functions as an example of a dependent cell determination unit, and when receiving a group cell construction request from the UE 2, the slave cell determination unit 131 is based on the location information of the cell formed by the eNB 1 received from another eNB 1. The slave cell included in the group cell 50 having the cell formed by the own station as the master cell is determined.
  • FIG. 21A is a sequence diagram illustrating a processing procedure when it is determined that the UE 2 is moving and the number of slave cells is increased.
  • UE2 periodically transmits a pilot signal to each eNB1 (step S1301).
  • the master control unit 12 of the eNB 1M calculates the received power of the pilot signal received via the master cell by the power calculation unit 123 (step S1302), and the received power information that is the calculation result is the slave cell change unit 132 of the eNB 1M. (Step S1303).
  • the master control unit 12 of the eNB 1M calculates the received power of the pilot signal received via the master cell by the power calculation unit 123 (steps S1304 and S1306), and changes the received power information as the calculation result to the slave cell change of the eNB 1M.
  • the data is transmitted to the unit 132 (steps S1305 and S1307).
  • the master control unit 12 of the eNB 1S calculates the reception power of the pilot signal received via the slave cell by the power calculation unit 123, and the received power information as a calculation result is transmitted to the slave control unit 13 of the eNB 1M X2. Transfer through the interface.
  • the slave cell changing unit 132 of the eNB 1M determines the position of the UE 2 estimated by comparing the received power indicated by the received power information received from each eNB 1S and the received power of the pilot signal received through the slave cell of the own station.
  • the movement state of the UE 2 is determined based on Specifically, the slave cell changing unit 132 of the eNB 1M stores history information of the UE 2 position estimated in the past in a predetermined storage area, and the UE 2 position based on the history information and the currently estimated UE 2 position. From this, the amount of change in the position of the UE2 is calculated. And the slave cell change part 132 of eNB1M determines with this UE2 moving, when the calculated variation
  • the slave cell changing unit 132 of the eNB1M transmits a slave request to the eNB1 in order to expand the group cell 50 (step S1309). Specifically, the slave cell changing unit 132 of the eNB 1M first adds a cell 5 other than the cell 5 included in the current group cell 50 and adjacent to the slave cell to the group cell 50. Determine as a slave cell. For example, when expanding the group cell 50 shown in FIG.
  • the slave cell changing unit 132 of the eNB 1M causes the cells 5d, 5h, 5j, 5k, 5l, 5m, 5n, 5o, which are adjacent to the slave cell of the current group cell 50, 5p, 5t, 5v, and 5x are determined as slave cells to be newly added.
  • the slave cell changing unit 132 of the eNB 1M transmits a slave request to the eNB 1 that forms the cell 5 to be slaved.
  • the slave cell changing unit 132 of the eNB 1M performs the following operations on the eNB 1b that forms the cell 5d, the eNB 1c that forms the cell 5h, the eNB 1d that forms the cells 5j and 5k, and the eNB 1e that forms the cells 5l and 5m. Send a slave request.
  • the slave cell changing unit 132 of the eNB 1M sends a slave request to the eNB 1f that forms the cells 5n and 5o, the eNB 1g that forms the cell 5p, the eNB 1h that forms the cell 5t, and the eNB 1j that forms the cells 5v and 5x. Send.
  • the cell information management unit 124 sets the cell to be slaved as a slave cell based on the slave request. Registration is performed (step S1310).
  • FIG. 21-2 is a sequence diagram illustrating a processing procedure when it is determined that the UE 2 is stationary and the number of slave cells is decreased. Note that the processing in steps S1351 to S1357 shown in FIG. 21-2 is the same as the processing in steps S1301 to 1307 shown in FIG. 21-1, and a description thereof will be omitted.
  • the slave cell changing unit 132 of the eNB 1M calculates the amount of change in the position of the UE 2 from the history information of the position of the UE 2 estimated in the past and the position information of the UE 2 estimated this time. As a result, the calculated amount of change is less than a predetermined value. If it is, it is determined that the UE2 is stationary (step S1358). When determining that the UE 2 is stationary, the slave cell changing unit 132 of the eNB 1M releases the slave cell included in the current group cell 50 in order to reduce the group cell 50. Then, the slave cell change unit 132 of the eNB 1M instructs the cell information management unit 124 to change the slave cell that is the target of slave release to a normal cell (step S1359).
  • the slave cell changing unit 132 of the eNB 1M stores the estimated location information history of the UE 2, and determines the movement state of the UE 2 by calculating the amount of change. And the slave cell change part 132 of eNB1M can perform management of a more efficient slave cell by changing the number of slave cells according to the determined movement state. That is, for example, when the UE 2 is moving, it is possible to reliably prevent the UE 2 from moving out of the group cell 50 by increasing the number of slave cells included in the group cell 50. On the other hand, when UE2 is stationary, it is possible to prevent unnecessary use of radio resources by reducing the number of slave cells included in group cell 50.
  • the transmission power of data transmitted via the master cell and the slave cell is common in the group cell 50, but the transmission power is not limited to this, and the transmission power may be different in the group cell 50.
  • the lower layer control unit 161 of the eNB 1M sets the transmission power higher for the cell 5 located at the center of the group cell 50, and the group cell 50 The transmission power is set to be lower for the cell 5 located at the outer edge.
  • FIG. 22 is a sequence diagram illustrating an example of a processing procedure when the transmission power in the group cell 50 is varied.
  • the lower layer control unit 161 of the eNB 1M indicates the downlink power that is set lower than the reference value for the eNB 1S that forms a slave cell located near the outer edge of the group cell 50. Transmit power information is transmitted via the X2 interface (step S1401). Then, the lower layer control unit 161 of the eNB 1S determines the transmission power of data to the UE 2 to be lower than the reference value based on the received downlink transmission power information (step S1402).
  • the lower layer control unit 161 of the eNB 1M determines the transmission power corresponding to the master cell that is the center of the group cell 50 to be higher than the reference (step S1403). Further, the lower layer control unit 161 of the eNB 1M determines the transmission power corresponding to the slave cell formed by the own station as a reference value (step S1404). In this way, the lower layer control unit 161 of the eNB 1M functions as an example of a common resource determination unit, and determines different transmission power for each master cell and slave cell that constructs the group cell 50.
  • the group cell 50 can be operated more efficiently.
  • the group cell 50 is formed concentrically around the master cell, the cell 5 located at the center of the group cell 50 is set to a higher transmission power, thereby enabling more reliable communication with the UE 2.
  • the transmission power can be lower for the cells 5 located at the outer edge of the group cell 50, the influence on the other cells 5 can be reduced.
  • FIG. 23 is a sequence diagram illustrating an example of a processing procedure when the downlink transmission power is changed based on feedback information from the UE2.
  • the eNB 1M and the eNB 1S transmit pilot signals through the master cell and the slave cell using the transmission power determined by the lower layer control unit 161 of the eNB 1M, respectively (step S1501). Subsequently, the UE 2 that has received these pilot signals via the radio link calculates the reception power of each pilot signal by the power calculation unit 123 (step S1502), and the received power information that is the calculation result of the eNB 1M via the master cell. It transmits to the lower layer control part 161 (step S1503).
  • the power calculation unit 123 when receiving a pilot signal from the eNB 1M and the eNB 1S, the power calculation unit 123 functions as an example of a received power information transmitting unit that transmits received power information indicating the received power of the pilot to the eNB 1M.
  • the lower layer control unit 161 of the eNB 1M determines the changed downlink transmission power for each master cell and slave cell based on the received reception power information (step S1504). For example, the lower layer control unit 161 of the eNB 1M corrects the transmission power corresponding to the master cell to be lower when the reception power of the pilot signal received by the UE 2 via the master cell is higher than a predetermined value. In addition, when the reception power of the pilot signal received by the UE 2 via the slave cell located at the outer edge of the group cell 50 is lower than a predetermined value, the lower layer control unit 161 of the eNB 1M sets the transmission power corresponding to the slave cell. Correct higher.
  • the lower layer control unit 161 of the eNB 1M functions as an example of a common resource determination unit, and when receiving the received power information of the pilot signal transmitted from the own station and the eNB 1S from the UE 2, based on the received power information, The transmission power determined for each master cell and slave cell is changed.
  • the lower layer control unit 161 of the eNB 1M sends the downlink transmission power information indicating the changed downlink transmission power to the lower layer control unit 161 of the eNB 1S. Send. Then, the lower layer control unit 161 of the eNB 1S changes the transmission power of the corresponding slave cell based on the downlink transmission power information received via the X2 interface (step S1506). Further, the lower layer control unit 161 of the eNB 1M changes the transmission power of the master cell (step S1507) and changes the transmission power of the slave cell (step S1508) based on the determination result in step S1504.
  • UE2 uses the received power information of the pilot signals received from eNB1M and eNB1S as feedback information, and changes the downlink transmission power corresponding to the master cell and slave cell based on the feedback information, thereby enabling the master cell and slave cell to Corresponding downlink transmission power can be optimized.
  • the feedback information transmitted from the UE2 is the reception power information of the pilot signal received by the UE2 from the eNB1M and the eNB1S. However, whether or not the downlink transmission power determined for each master cell and slave cell is appropriate is lower than the eNB1M. Any information that can be determined by the layer control unit 161 may be used. For example, an error rate may be used.
  • FIG. 24-1 is a diagram illustrating a state in which some eNBs 1S do not perform data transmission to the UE 2
  • FIG. 24-2 illustrates that the eNB 1S that does not perform data transmission to the UE 2 is changed as the UE 2 moves. It is a figure which shows a mode.
  • a group cell 50 is constructed as a group cell for the UE 2a, in which the cell 5a is a master cell and the cells 5b, 5c, 5d to 5g, 5i, 5t, and 5v are slave cells.
  • the lower layer control unit 161 of the eNB 1a that is the eNB 1M sets power control only for the master cell and the slave cell adjacent to the master cell.
  • the lower layer control unit 161 of the eNB 1a powers only the cell 5a that is the master cell and the cells 5b, 5c, 5e, 5f, 5g, and 5i adjacent to the cell 5a. Controlled.
  • the lower layer control part 161 of eNB1a transmits a power control object notification with respect to eNB1S which forms the slave cell used as the object of power control.
  • the lower layer control unit 161 of the eNB 1a sends a power control target notification to the eNB 1b that forms the cells 5e and 5f that are the targets of power control and the eNB 1c that forms the cells 5g and 5i via the X2 interface. Send through.
  • the eNBs 1b and 1c that have received the power control target notification transmit the data using the common radio resource in the group cell 50.
  • the lower layer control unit 161 of the eNB 1a is not subject to power control for the eNB 1b that forms the cell 5d that is a slave cell that is not the target of power control, the eNB 1h that forms the cell 5t, and the eNB 1j that forms the cell 5v.
  • a notification is sent via the X2 interface.
  • the eNB 1b, 1h, 1j that has received the power control non-target notification does not transmit the data even when it receives data from the data transfer processing unit 171 of the eNB 1M to the UE 2, and the group cell 50 In this state, only the common radio resource is secured.
  • the cell 5 to be subjected to power control is changed as the UE 2 moves.
  • the UE 2 moves from the cell 5a formed by the eNB 1a to the cell 5e formed by the eNB 1b.
  • the lower layer control unit 161 of the eNB 1b that has newly become the eNB 1M sets the cell 5e as the master cell and the cells 5a, 5d, 5f, 5g, 5t, and 5v adjacent to the cell 5e to be subjected to power control.
  • the cells 5b, 5c, 5i not adjacent to 5e are excluded from power control.
  • the cells 5d, 5t, and 5v that are not subject to power control before the UE2 moves are newly subject to power control, and the cells 5b, 5c, and 5i that are subject to power control before the UE2 move are Not subject to power control.
  • the lower layer control unit 161 of the eNB 1a functions as an example of a common resource determination unit, and transmits a power control target notification to a predetermined slave cell among slave cells that construct the group cell 50.
  • the lower layer processing unit 14 functions as a lower layer processing unit, and transmits data to the UE 2 using a common radio resource in the group cell 50 only when a power control target notification is received from the eNB 1M. .
  • FIG. 25 is a diagram illustrating an example of a processing procedure when dynamic control of a downlink power transmission target is performed.
  • the eNB 1M specifies the position of the UE 2 in advance by comparing the received power of the pilot signal.
  • the lower layer control unit 161 of the eNB 1M selects a slave cell adjacent to the master cell (step S1601), and transmits a power control target notification to the eNB 1S that forms the selected slave cell (Ste S1602). Also, the lower layer control unit 161 of the eNB 1M registers in the cell information management unit 124 that the master cell and slave cell of the own station are power control target cells (step S1603). Also, the lower layer control unit 161 of the eNB 1S that has received the power control target notification from the eNB 1M registers in the cell information management unit 124 that the slave cell of the local station is the power control target cell based on the power control target notification. (Step S1604).
  • eNB1S which received eNB1M and the power control object notification can judge that the master cell and slave cell which an own station forms are power control object cells.
  • the eNB 1M and the eNB 1S that form the power control target cell transmit data to the UE 2 using a common radio resource in the group cell 50.
  • the lower layer control unit 161 of the eNB 1M transmits a power control non-target notification to the eNB 1S that forms a slave cell that is not adjacent to the master cell (step S1605). Then, the lower layer control unit 161 of the eNB 1S that has received the power control non-target notification via the X2 interface registers in the cell information management unit 124 that the slave cell formed by itself is not the power control target (step S1606). Accordingly, the eNB 1S that has received the power control non-target notification can determine that the slave cell formed by the own station is out of the power control target.
  • the eNB 1S that forms a slave cell that is not subject to power control only secures radio resources that are common in the group cell 50 and data is transferred from the data transfer processing unit 171 of the eNB 1M to the UE 2, The data is not transmitted to UE2.
  • the slave cell that is far from the UE 2 and has little influence on the radio communication with the UE 2 does not perform data transmission to the UE 2 to perform group transmission. Interference with the neighboring cells of the cell 50 can be suppressed.
  • the radio resource is used to transmit to UE2. Data can be transmitted quickly.
  • the lower layer control unit 161 of the eNB 1S that forms the power control non-target cell temporarily releases the secured radio resource when it is necessary to transmit other data with high priority, and the priority May be assigned to transmission of high data.
  • FIG. 26 is a sequence diagram illustrating a processing procedure of uplink transmission power control processing.
  • UE2 periodically transmits a pilot signal to each eNB1 (step S1701).
  • the lower layer control unit 161 of the eNB 1M calculates the reception power of the pilot signal received via the master cell by the power calculation unit 123, and determines the uplink transmission power value based on the calculation result (step S1702).
  • the lower layer control unit 161 of the eNB 1M specifies the communication quality of radio communication with the UE 2 performed via the master cell, based on the received power of the pilot signal received from the UE 2.
  • the lower layer control unit 161 of the eNB 1M determines the optimum uplink transmission power, for example, by increasing the uplink transmission power when the specified communication quality is low.
  • the lower layer control unit 161 of the eNB 1M transmits a transmission power control signal (Transmit Power Control: TPC) including information on the uplink transmission power determined in Step S1702 to the UE 2 via the master cell (Step S1703). Further, UE2 changes the uplink transmission power value based on the received TPC as uplink transmission power control (step S1704). And UE2 transmits a pilot signal to eNB1M again using the uplink transmission power value after a change (step S1705). Thus, UE2 and eNB1M control uplink transmission power by repeating the processes of steps S1701 to S1705.
  • TPC Transmission Power Control
  • FIG. 27 is a sequence diagram showing a processing procedure of uplink transmission power control processing based on the received power of the pilot signal received via the master cell and the slave cell.
  • UE2 periodically transmits a pilot signal to each eNB1 (step S1801). Subsequently, the master control unit 12 of the eNB 1M calculates the received power of the pilot signal received via the master cell by the power calculation unit 123 (step S1802), and transmits the received power information as a calculation result to the slave cell change unit 132. (Step S1803). Similarly, the master control unit 12 of the eNB 1M calculates the reception power of the pilot signal received via the slave cell by the power calculation unit 123 (step S1804), and the received power information as the calculation result to the slave cell change unit 132. Transmit (step S1805).
  • the master control unit 12 of the eNB 1S calculates the received power of the pilot signal received via the cell 5 by the power calculation unit 123 (step S1806), and the received power information as a calculation result is sent to the slave control unit 13 of the eNB 1M.
  • the data is transferred via the X2 interface (step S1807).
  • the slave cell changing unit 132 of the eNB 1M determines an uplink transmission power value based on the received power information received from the master control unit 12 of the own station or another eNB 1 (step S1808). For example, when the reception power of the pilot signal received via the slave cell located at the outer edge of the group cell 50 is higher than the reference value, the lower layer control unit 161 of the eNB 1M lowers the uplink transmission power value from the current value. Thus, the optimum uplink transmission power is determined.
  • the lower layer control unit 161 of the eNB 1M functions as an example of a common resource determination unit, and the transmission power when the UE 2 transmits a signal to the eNB 1 based on the received power information acquired from the own station and each eNB 1S. A certain upstream transmission power is changed.
  • the lower layer control unit 161 of the eNB 1M transmits a TPC including information on the uplink transmission power determined in step S1808 to the UE 2 via the master cell (step S1809). And UE2 changes an uplink transmission power value based on received TPC as uplink transmission power control (step S1810).
  • the UE 2 and the group cell 50 Wireless communication can be performed more appropriately.
  • the base station disclosed in this case is not limited to the eNB, but may be a radio base station (BS: Base Station) of a generation prior to LTE / SAE.
  • BS Base Station
  • the cell 5 adjacent to the master cell is determined as the slave cell.
  • the cell 5 determined as the slave cell is not necessarily adjacent to the master cell. That is, the shape of the group cell 50 constructed by the technique disclosed in this case may be any shape.
  • the cell information management unit 124 manages information such as whether the cell 5 formed by the own station is a master cell or a slave cell.
  • the present invention is not limited to this.
  • a state management unit that manages the state of cell 5 such as whether the cell 5 formed by the own station is a master cell or a slave cell is provided for each cell 5, and the state of each cell 5 is managed by these state managements.
  • Each section may manage each.
  • each state management unit functions as an example of the reception power information transmission unit, calculates the reception power of the pilot signal received via each cell 5, and outputs the calculation result to the master control unit 12 or the eNB 1M. You may make it report to the slave control part 13.
  • FIG. In this way, by providing the eNB 1 with a state management unit that manages each cell 5, processing by the master control unit 12 can be reduced.
  • the eNB 1M and the eNB 1S are configured to grasp which eNB 1 is the eNB 1M and which eNB 1 is the eNB 1S by transmitting information by themselves.
  • the present invention is not limited to this, and the MME / UPE 3 may manage information on the eNB 1M and the eNB 1S that construct the group cell 50, and notify the eNB 1M and the eNB 1S as necessary.
  • the eNB 1 that has become the eNB 1M or the eNB 1S notifies the MME / UPE 3 which cell of its own station has become the master cell or the slave cell, or the slave release target. And MME / UPE3 will update the status information of the master cell and slave cell which comprise the group cell 50, and will notify to eNB1M and eNB1S, if this notification is received. In this way, the eNB 1M and the eNB 1S may be able to grasp which eNB 1 is the eNB 1M and which eNB 1 is the eNB 1S.
  • S Mobile communication system 1a to 1j Radio base station 2a, 2b UE 3 MME / UPE 5a to 5x cell 11 handover processing unit 12 master control unit 13 slave control unit 14 lower layer processing unit 15 upper layer processing unit 16 scheduling unit 17 data buffer unit 121 master cell determination unit 122 master cell change unit 123 power calculation unit 124 cell information management unit 131 Slave cell determination unit 132 Slave cell change unit 161 Lower layer control unit 162 Feedback control unit 171 Data transfer processing unit 172 Data sharing management unit 20 IF unit 21 Handover processing unit 22 Operation input unit 23 Signal transmission unit 24 Power calculation unit 25 Master cell Change determination unit 26 Slave cell change determination unit

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  • Mobile Radio Communication Systems (AREA)

Abstract

La présente invention a pour but de prévenir une détérioration de la qualité des communications et des interruptions dans les communications dues à une opération de transfert intercellulaire quand une station mobile se déplace fréquemment entre des cellules. Pour atteindre cet objectif, quand eNB1 reçoit une requête de l'UE2 de bâtir une cellule de groupe, il détermine des cellules esclaves comprises dans une cellule de groupe (50) avec une cellule qu'il forme comme une cellule maîtresse, il détermine une ressource sans fil pour la communication avec l'UE2 et pour l'allocation en commun à une station de base (eNB1S) qui forme des cellules esclaves et à lui-même (eNB1M), et il transmet à l'eNB1S des informations relatives à la ressource sans fil qui a été déterminée, et, de ce fait, eNB1M et eNB1S assurent une ressource sans fil partagée à l'intérieur de la cellule de groupe.
PCT/JP2009/059802 2009-05-28 2009-05-28 Système de communication mobile, station de base, station mobile, et procédé de communication sans fil WO2010137155A1 (fr)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012169698A (ja) * 2011-02-09 2012-09-06 Mitsubishi Electric Corp 無線通信システム
WO2012131857A1 (fr) * 2011-03-25 2012-10-04 富士通株式会社 Station de base, système de communication et procédé de communication
EP2932626A4 (fr) * 2012-12-14 2016-11-02 Samsung Electronics Co Ltd Appareil et procédé pour gérer la mobilité dans un système de communication sans fil

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JPH06327048A (ja) * 1993-05-18 1994-11-25 Oki Electric Ind Co Ltd 移動体通信システム
WO2006073084A1 (fr) * 2005-01-07 2006-07-13 Matsushita Electric Industrial Co., Ltd. Systeme de communication, dispositif de gestion de reseau, procede de gestion de reseau, dispositif de gestion de communication, et procede de gestion de communication
JP2009049974A (ja) * 2007-08-16 2009-03-05 Korea Electronics Telecommun 端末移動速度に基づく網資源予約方法、網資源予約装置、及び、網資源予約システム、並びに、これに用いられる移動端末

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH06327048A (ja) * 1993-05-18 1994-11-25 Oki Electric Ind Co Ltd 移動体通信システム
WO2006073084A1 (fr) * 2005-01-07 2006-07-13 Matsushita Electric Industrial Co., Ltd. Systeme de communication, dispositif de gestion de reseau, procede de gestion de reseau, dispositif de gestion de communication, et procede de gestion de communication
JP2009049974A (ja) * 2007-08-16 2009-03-05 Korea Electronics Telecommun 端末移動速度に基づく網資源予約方法、網資源予約装置、及び、網資源予約システム、並びに、これに用いられる移動端末

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2012169698A (ja) * 2011-02-09 2012-09-06 Mitsubishi Electric Corp 無線通信システム
WO2012131857A1 (fr) * 2011-03-25 2012-10-04 富士通株式会社 Station de base, système de communication et procédé de communication
JP5692360B2 (ja) * 2011-03-25 2015-04-01 富士通株式会社 基地局、無線通信システム、通信システムおよび通信方法
US9504094B2 (en) 2011-03-25 2016-11-22 Fujitsu Limited Base station, communication system, and communication method
EP2932626A4 (fr) * 2012-12-14 2016-11-02 Samsung Electronics Co Ltd Appareil et procédé pour gérer la mobilité dans un système de communication sans fil
US10097988B2 (en) 2012-12-14 2018-10-09 Samsung Electronics Co., Ltd. Apparatus and method for managing mobility in a wireless communication system

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