WO2010137155A1

WO2010137155A1 - Mobile communication system, base station, mobile station, and wireless communication method

Info

Publication number: WO2010137155A1
Application number: PCT/JP2009/059802
Authority: WO
Inventors: 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
Original assignee: 富士通株式会社
Priority date: 2009-05-28
Filing date: 2009-05-28
Publication date: 2010-12-02

Abstract

To prevent deterioration in communication quality and communication interruptions due to handover processing when a mobile station moves frequently between cells. To achieve this, when eNB1 receives a request from UE2 to build a group cell, it determines slave cells included in a group cell (50) with a cell that it forms as a master cell, determines a wireless resource for communication with UE2 and for allocation in common to a base station (eNB1S) that forms slave cells and to itself (eNB1M), and transmits to eNB1S information related to the wireless resource that has been determined, and thus eNB1M and eNB1S secure a shared wireless resource within the group cell.

Description

Mobile communication system, base station, mobile station, and radio communication method

The present invention relates to a mobile communication system, a base station, a mobile station, and a radio communication method.

Conventionally, in a mobile communication system in which wireless communication is performed between a mobile station and a base station, when the mobile station moves from a cell in the service area to another cell, the base station that is a communication partner with the mobile station is switched. Thus, a handover process for continuing wireless communication is performed.

Here, the handover process performed in the conventional mobile communication system will be described with reference to FIG. FIG. 28 is a sequence diagram illustrating an example of a processing procedure of a handover process in a conventional mobile communication system.

As shown in FIG. 28, 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, When moving to a cell formed by a HO destination base station, a handover request is transmitted to the HO destination base station via the HO source base station (step S001). Here, 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.

Subsequently, 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).

Subsequently, the HO source base station transmits a handover command signal (Handover Command) to the mobile station (step S005). Note that the handover instruction signal includes information related to radio resources used by the mobile station for radio communication with the HO destination base 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.

JP-A-10-136426

However, in a conventional mobile communication system, when a mobile station frequently moves between cells, handover processing frequently occurs, resulting in deterioration in communication quality between the mobile station and the base station, or handover processing. There is a risk that communication may be interrupted due to failure.

That is, as described above, 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.

In order to solve the above-described problems and achieve the object, 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 A radio resource for communication with the mobile station, and a common resource determination for determining a radio resource to be commonly allocated to a base station and a local station forming a subordinate cell determined by the subordinate cell determining means Means, radio resource information transmitting means for transmitting information on radio resources determined by the common resource determining means to a base station forming the dependent cell, radio resources determined by the common resource determining means, or Lower layer processing means for securing radio resources based on radio resource information received from base stations forming a reference cell.

According to one aspect of the mobile communication system, 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.

Hereinafter, embodiments of a mobile communication system, a base station, a mobile station, and a radio communication method according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

[1. Overview of mobile communication system]
First, an outline of a mobile communication system according to the present embodiment will be described with reference to the drawings. 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, and FIG. 3 is a diagram for explaining how a group cell is constructed for each UE FIG. In the following, 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. However, the technology disclosed in this case is not limited to such a communication system.

As shown in FIG. 1, the mobile communication system S according to the present embodiment includes eNBs (evolved Node-B) 1a to 1j, UEs (User Equipment) 2a and 2b, and MME / UPE (Mobile Management Entity / User Plane). Entity) 3.

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.

Here, in a wireless communication system based on 3GPP-LTE, a combination of a base station controller (RNC: Radio Network Controller) and a base station (Node-B) in LTE / SAE (Long Term Evolution / System Architecture Evolution) Instead, an eNB (enhanced Node-B) is provided. That is, the eNBs 1a to 1j according to the present embodiment have both the Node-B function and the RNC function. In addition to the function of performing radio communication with the

UEs

2a and 2b, the function of controlling the handover process, etc. Have

In this embodiment, eNBs are connected to each other using a communication interface called X2 (hereinafter referred to as “X2 interface”). The X2 interface is a newly added interface in 3GPP-LTE. By connecting the eNBs 1a to 1j with the X2 interface, various signals can be directly transferred between the eNBs. In the following, 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. In the following,

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. In the present embodiment, 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.

In the mobile communication system S according to the present embodiment, 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. Similarly, 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, and eNB 1j forms cells 5v to 5x. . In the following, any of the cells 5a to 5x is simply referred to as “cell 5”.

Then, in the mobile communication system S according to the present embodiment, in response to a request from the UE 2, a group cell that is a cell in which cells formed by a plurality of eNBs 1 are virtually integrated is constructed. For example, as illustrated in FIG. 2, when 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. Then, 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.

First, 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. In the present embodiment, the eNB 1a determines a neighboring cell of the cell 5a that is the reference cell as a subordinate cell. For example, 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.

Subsequently, 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. Then, 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.

And eNB1b and 1c which received eNB1a and radio | wireless resource information ensure the common radio | wireless resource determined by eNB1a as a radio | wireless resource for communication with UE2a. Thereby, it will be in the state by which the radio | wireless resource for communication with UE2a was shared within the group cell 50. FIG.

Subsequently, the eNB 1a transfers data to be transmitted to the UE 2a to the

eNB

1b and 1c. And eNB1a and eNB1b, 1c transmit the data to UE2a simultaneously using the radio | wireless resource shared within the group cell 50. FIG. Thereby, 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.

As described above, the mobile communication system S according to the present embodiment 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. . As a result, the UE 2 can treat the group cell 50 virtually as a single cell.

That is, since the UE 2 has already transmitted data from the destination cell 5 to the UE 2 even if the UE 2 moves from the cell 5 in the service area to another cell 5 in the group cell 50, It is possible to move without performing a handover process. Accordingly, 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.

Here, hereinafter, the reference cell is referred to as a “master cell” and the subordinate cell is referred to as a “slave cell”. Moreover, below, eNB1 which forms a master cell is called "eNB1M", and eNB1 which forms only a slave cell is called "eNB1S."

In this embodiment, the group cell 50 is constructed in units of UE2. For example, as illustrated in FIG. 3, 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. Specifically, 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.

Also, 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.

That is, each eNB 1 manages for each UE 2 whether the cell formed by itself is a master cell or a slave cell. In the following,

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”.

Moreover, 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.

[2. About the configuration of eNB and UE]
Next, the configuration of the eNB 1 according to the present embodiment will be specifically described. FIG. 4 is a block diagram illustrating a configuration of the eNB 1 according to the present embodiment. As illustrated in FIG. 4, 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. Specifically, 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.

When the master cell determination unit 121 receives a group cell construction request from the UE 2, 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.

When 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. As a result, 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.

Further, when the own station is the eNB 1M, 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.

When the reception power of the pilot signal received via the slave cell is higher than the reception power of the pilot signal received 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. Specifically, for example, when the own station is the eNB 1M, it is assumed that the slave cell having the highest received power in the group cell 50 is the cell 5 formed by the own station. In such a case, 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. Thus, when 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.

For example, when the local station is the eNB 1M, it is assumed that the slave cell having the highest received power in the group cell 50 is the cell 5 formed by another eNB 1. In such a case, 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. In such a case, the master cell changing unit 122 instructs the cell information managing unit 124 to change the current master cell to a slave cell.

Moreover, 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. When the master cell change notification is received and becomes eNB1M, 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.

Thus, when the communication quality between the UE 2 and the master cell is higher than the communication quality between the UE 2 and the master cell, 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. More specifically, 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. Here, in the present embodiment, the power calculation by the power calculation unit 123 is performed for each cell 5 formed by the own station. Moreover, 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. Moreover, 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.

As described above, when the power calculation unit 123 and the IF unit 10 receive the pilot signal from the UE 2, 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. Here, the slave cell determination request includes information indicating which cell 5 of the own station is the master cell. In addition, 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.

In addition, 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. Note that the slave request includes information indicating which cell 5 is the master cell. Thereby, eNB1 which received the slave request | requirement can identify which eNB1 is eNB1M. Such information is stored in a predetermined storage area.

As described above, when the slave cell determining unit 131 receives a group cell construction request from the UE 2, 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. FIG.

Subsequently, 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.

Subsequently, when the position of the UE 2 estimated based on each received power is located in the vicinity of the end of 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. 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. Such a slave request includes information for specifying the cell 5 to be slaved, information for specifying the eNB 1M, and the like.

On the other hand, 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. Similarly, when the cell 5 newly determined as the slave cell is the cell 5 formed by the own station, 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.

Also, 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.

When the slave cell changing unit 132 of the eNB 1S receives the slave release notification from the eNB 1M, 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.

As described above, 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. For example, 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. Also, 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.

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. Specifically, 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. When 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.

In addition, 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. Specifically, 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. In the present embodiment, 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.

Here, the processing by the scheduling unit 16 and the data buffer unit 17 is performed between the processing by the upper layer processing unit 15 and the processing by the lower layer processing unit 14. Hereinafter, the processing executed by the scheduling unit 16 and the data buffer unit 17 will be described more specifically with reference to FIG. FIG. 5 is a diagram for explaining processing executed by the scheduling unit 16 and the data buffer unit 17.

In this embodiment, 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.

As described above, 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.

Subsequently, when the RLC-PDU is received from the upper layer processing unit 15, 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. Upon receiving the data arrival notification, 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.

As described above, 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.

Also, 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.

Specifically, when receiving a notification from the upper layer processing unit 15 that data transmission to the UE 2 is performed, 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. Here, the lower layer information includes information (resource allocation status information) related to radio resources allocated to each UE 2 located in the own station.

Subsequently, when 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. Send through. As described above, 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. .

Then, 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 | wireless resource as a radio | wireless resource for allocating in common with the base station which forms a slave cell, and an own station.

In addition, when receiving the feedback information from the feedback control unit 162, 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.

Subsequently, 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.

In this way, 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.

Subsequently, when receiving the radio resource information and the transmission power information, 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.

Thus, in the mobile communication system S according to the present embodiment, 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.

Further, in the mobile communication system S according to the present embodiment, 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. Thereby, 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.

Subsequently, the configuration of the UE 2 according to the present embodiment will be specifically described. FIG. 6 is a block diagram illustrating the configuration of the UE according to the present embodiment. As illustrated in FIG. 6, 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. In particular, the operation input unit 22 according to the present embodiment accepts a group cell construction request operation for requesting construction of the group cell 50 from the user. Here, 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. In particular, the signal transmission unit 23 according to the present embodiment 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. Moreover, 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.

[3. Specific operation of eNB and UE]
[3.1. About handover processing]
Next, specific operations of the eNB 1 and the UE 2 according to the present embodiment will be described. First, the handover process performed between UE2 and eNB1 is demonstrated. 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. In addition, in FIG. 7, when 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.

As illustrated in FIG. 7, when moving from the cell 5a formed by the currently communicating eNB 1a to the cell 5f formed by the eNB 1b, the handover processing unit 21 of the UE 2a transmits a handover request to the eNB 1b via the eNB 1a ( Step S101). Here, 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.

Subsequently, 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). .

Subsequently, 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.

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). Then, 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.

[3.2. Overview of eNB1M processing procedure]
Then, the outline | summary of the process sequence of eNB1M is demonstrated. FIG. 8 is a flowchart illustrating an outline of a processing procedure of the eNB 1M according to the present embodiment.

As shown in FIG. 8, 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.

Subsequently, 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).

Subsequently, 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.

In this process, when it is determined that the UE 2 is located at the end of the group cell 50 (Yes at Step S204), 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.

On the other hand, when UE2 is not located at the end of the group cell 50 in Step S204 (No in Step S204), 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.

In such processing, 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. When the power is higher than the power, the master cell changing unit 122 of the eNB 1M changes the master cell (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.

[3.3. About master cell determination process]
Next, the master cell determination process in step S201 will be described. FIG. 9 is a sequence diagram illustrating an example of a processing procedure of master cell determination processing according to the present embodiment.

As illustrated in FIG. 9, when 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. . Subsequently, 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.

Then, 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). Thereby, 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.

As described above, in the mobile communication system S according to the present embodiment, when a predetermined button is pressed by the user or a predetermined application is activated, 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.

[3.4. About slave cell decision processing]
Next, the slave cell determination process in step S202 will be described. 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.

As illustrated in FIG. 10, 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. In addition, 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).

Subsequently, 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). In addition, when the cell 5 of the own station is determined as a slave cell, 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).

Also, 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). Note that the slave request includes information indicating which cell 5 is the master cell. Thereby, eNB1 which received the slave request | requirement can identify which eNB1 is eNB1M. Such information is stored in a predetermined storage area of the eNB 1.

Thus, 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.

[3.5. Data transfer processing and data sharing management processing]
Next, the data transfer process and the data sharing management process in step S203 will be described. 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.

As shown in FIG. 11, 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). .

Upon receiving the data arrival notification, 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).

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. 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). Similarly, when the timing for transmitting the MAC-SDU has arrived based on the transmission timing information (step S509), the data transfer processing unit 171 of the eNB 1S transmits the MAC-SDU to each lower layer processing unit 14 ( Step S510).

[3.6. About radio resource sharing processing and retransmission control processing]
Next, the radio resource sharing process and the retransmission control process in step S203 will be described. 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.

As shown in FIG. 12, when feedback information is received from the lower layer processing unit 14 (step S601), the feedback control unit 162 of the eNB 1M makes a retransmission request to the lower layer control unit 161 (step S602). Here, the feedback information is a reception result of the uplink signal of UE2.

Subsequently, 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). Similarly, 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).

Subsequently, 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 | wireless resource as a radio | wireless resource for allocating in common with the base station which forms a slave cell, and an own station.

Subsequently, 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 | wireless resource information transmits the received radio | wireless resource information to the lower layer process part 14 of an own station (step S609).

Then, 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). Similarly, 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). Thereby, the transmission data to UE2 are simultaneously transmitted from eNB1M and eNB1S using the radio | wireless resource common in the group cell 50. 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.

[3.7. About master cell change processing]
Next, the master cell change process in step S205 will be described. 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.

As shown in FIG. 13A, 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).

Subsequently, 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.

Here, when the new master cell is a cell formed by the eNB 1M, 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). As a result, 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). In such a case, the current eNB 1M continues to function as the eNB 1M.

On the other hand, when the new master cell is a cell other than the cell formed by the eNB 1M, a process as shown in FIG. 13-2 is performed. 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.

In 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).

Further, when receiving the master cell change notification from the eNB 1M, 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). Thereby, 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. And when a master cell change notification is received and becomes eNB1M, 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.

Thus, in the mobile communication system S according to the present embodiment, when 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.

[3.8. About slave cell change processing]
Next, the slave cell change process in step S207 will be described. FIG. 14 is a sequence diagram illustrating an example of the processing procedure of the slave cell change processing according to the present embodiment.

As shown in FIG. 14, 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). Further, 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).

Subsequently, 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).

In addition, when the slave cell changing unit 132 of the eNB 1M becomes a release target from the group cell 50, 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). In addition, when 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).

Thus, in the mobile communication system S according to the present embodiment, 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.

[Effect of Example 1]
As described above, according to the present embodiment, 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. .

Further, according to the present embodiment, 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.

That is, according to the present embodiment, when the communication quality between the UE2 and the slave cell is higher than the communication quality between the UE2 and the master cell, 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.

Further, according to the present embodiment, 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. In such a case, 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.

In addition, according to the present embodiment, since the change of the master cell and the change of the slave cell are performed independently, the processing for the reconstruction of the group cell 50 can be distributed.

By the way, 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. In addition, the same code | symbol is attached | subjected about the same thing as the already demonstrated structure, and the description is abbreviate | omitted.

[Automatic transmission of group cell construction request]
In the above embodiment, 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.

As illustrated in FIG. 15, 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. (Step S901). Here, the lower layer processing unit 14 according to the present embodiment 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. Send. Thus, 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.

Subsequently, 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 | assemble the group cell 50 is contained in the alerting | reporting information received from eNB1 (step S902 affirmation), UE2 will construct a group cell to this eNB1. A request is transmitted (step S903). Then, the eNB 1 that has received the group cell construction request via the cell 5 where the UE 2 is located registers the cell 5 as a master cell in the cell information management unit 124 (step S904).

As described above, 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.

[Master cell change processing by power calculation of UE2]
In the above embodiment, the eNB 1M and the eNB 1S calculate the received power of the pilot signal transmitted from the UE 2, and the master cell changing unit 122 of the eNB 1M compares the received power to determine a new master cell. UE2 may determine a correct master cell. Hereinafter, such a case will be described. FIG. 16 is a block diagram illustrating a configuration of the UE 2 according to another embodiment.

16, 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. Then, when the cell 5 showing the highest received power is a slave cell, 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.

Next, the specific operation of the master cell change process in such a case will be described. 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.

As shown in FIG. 17-1, 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).

Subsequently, 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. (Step S1003). Specifically, when the cell 5 indicating the highest received power among the received power information acquired from the power calculator 24 is a slave cell, the master cell change determination unit 25 determines the slave cell as a new master cell. . Then, 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.

As described above, 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.

Here, when the new master cell is a cell formed by the eNB 1M, 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).

On the other hand, when the new master cell is a cell other than the cell formed by the eNB 1M, a process as shown in FIG. 17-2 is performed. 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.

When the cell 5 having the highest pilot signal reception power is the slave cell formed by the eNB 1S in step S1054 of FIG. 17-2, 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). In addition, 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).

Further, when receiving the master cell change notification from the eNB 1M, 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). Thereby, this eNB1S comes to function as eNB1M. As described above, when 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.

Thus, by selecting a new master cell based on the received power of the pilot signal received by the UE 2 from the eNB 1M and the eNB 1S, the load on the master cell changing unit 122 of the eNB 1M can be reduced.

[Slave cell change processing by power calculation of UE2]
In the above embodiment, the eNB 1M and the eNB 1S calculate the received power of the pilot signal received from the UE 2, and the slave cell changing unit 132 of the eNB 1M compares the received power to determine a new slave cell. The UE2 may determine a new slave cell. Hereinafter, such a case will be described. FIG. 18 is a block diagram illustrating a configuration of the UE 2 according to another embodiment.

As shown in FIG. 18, 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.

Subsequently, when the estimated position of the own station is close to the end of the group cell 50, 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.

As described above, 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. In addition, UE2 can identify eNB1M and eNB1S by acquiring the information regarding eNB1M and eNB1S which construct the group cell 50 from eNB1M regularly.

Next, the specific operation of the slave cell change process in such a case will be described. FIG. 19 is a sequence diagram illustrating another example of the processing procedure of the slave cell change process.

As shown in FIG. 19, 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).

Subsequently, when 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).

Subsequently, 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).

Then, 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). As described above, 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.

Thus, by selecting the slave cell to be added to the group cell 50 or the slave cell to be released based on the received power of the pilot signal received by the UE 2 from the eNB 1M and the eNB 1S, the load on the eNB 1M can be reduced.

[Slave cell determination processing based on position coordinate information of eNB1]
In the above-described embodiment, the slave cell is determined or changed based on the location information of the cell 5 formed by each eNB 1 stored in advance in a predetermined storage area. You may receive from each eNB1 when performing determination or a change of a cell. Hereinafter, such a case will be described. 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.

As shown in FIG. 20, 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). Here, it is assumed that 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.

Subsequently, 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.

Subsequently, 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). When the cell 5 formed by the own station is determined as a slave cell, 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.

Then, 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). As a result, 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.

As described above, 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.

[Change in number of slave cells according to UE2 movement status]
In the above-described embodiment, the cell 5 adjacent to the master cell is determined as the slave cell. However, the number of slave cells constituting the group cell 50 may be changed according to the movement state of the UE 2. Hereinafter, such a case will be described. 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.

As shown in FIG. 21-1, UE2 periodically transmits a pilot signal to each eNB1 (step S1301). 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 S1302), and the received power information that is the calculation result is the slave cell change unit 132 of the eNB 1M. (Step S1303). Similarly, 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).

Similarly, 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.

Subsequently, 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 | change_quantity is more than predetermined value (step S1308).

If it is determined in step S1308 that the UE2 is moving, 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. 2, 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.

Subsequently, 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. For example, in the above example, 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. Similarly, 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.

Subsequently, the slave cell determination unit 131 of the eNB 1 that has received the slave request from the eNB 1M via the X2 interface, 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).

On the other hand, when UE2 is stationary, the group cell may be reduced. 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).

As described above, 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.

[Downlink power control]
In the above embodiment, 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. For example, when the group cell 50 is formed concentrically around the master cell, 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. Hereinafter, such a case will be described. FIG. 22 is a sequence diagram illustrating an example of a processing procedure when the transmission power in the group cell 50 is varied.

As illustrated in FIG. 22, 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).

On the other hand, 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.

Thus, by making the transmission power different in the group cell 50, the group cell 50 can be operated more efficiently. For example, when 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. In addition, by setting the transmission power to 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.

[Downlink power control based on feedback information from UE2]
When the downlink transmission power is varied within the group cell 50, the set transmission power may be corrected based on feedback information from the UE2. Hereinafter, such a case will be described. 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.

As shown in FIG. 23, 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).

Thus, 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.

Subsequently, 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.

As described above, 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.

When the downlink transmission power is changed for each master cell and slave cell in this way, 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.

Thus, 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.

Note that 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.

[Dynamic control of downlink power transmission target]
In the said Example, although all eNB1M and eNB1S which comprise the group cell 50 decided to transmit the data to UE2, not only this but some eNB1S do not perform the data transmission to UE2 Also good. Hereinafter, such a case will be described. FIG. 24-1 is a diagram illustrating a state in which some eNBs 1S do not perform data transmission to the UE 2, and 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.

As shown in FIG. 24-1, 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. To do. In such a case, 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. Specifically, as illustrated in FIG. 24-1, 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.

And 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. Specifically, 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. Thus, when receiving data from the data transfer processing unit 171 of the eNB 1M to the UE 2, 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.

On the other hand, 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. As a result, 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.

Further, when the UE 2 moves in the group cell 50, the cell 5 to be subjected to power control is changed as the UE 2 moves. For example, as illustrated in FIG. 24-2, it is assumed that the UE 2 moves from the cell 5a formed by the eNB 1a to the cell 5e formed by the eNB 1b. In such a case, 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. As a result, 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.

Thus, 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. Further, 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. .

Next, a specific processing procedure in such a case will be described. FIG. 25 is a diagram illustrating an example of a processing procedure when dynamic control of a downlink power transmission target is performed. In FIG. 25, it is assumed that the eNB 1M specifies the position of the UE 2 in advance by comparing the received power of the pilot signal.

As illustrated in FIG. 25, 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 ( Step 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). Thereby, 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.

Meanwhile, 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. Even when 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.

As described above, among the slave cells included in the group cell 50, 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. In addition, even if it is not subject to power control, by securing only radio resources, when a non-power target cell becomes a power control target cell due to movement of UE2, the radio resource is used to transmit to UE2. Data can be transmitted quickly.

Note that 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.

[Uplink transmission power control]
Here, a general control method of uplink transmission power will be described. FIG. 26 is a sequence diagram illustrating a processing procedure of uplink transmission power control processing.

As shown in FIG. 26, UE2 periodically transmits a pilot signal to each eNB1 (step S1701). Subsequently, 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). Specifically, 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. Then, 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.

Subsequently, 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.

[Uplink transmission power control based on feedback information from eNB1M and eNB1S]
In the above example, the lower layer control unit 161 of the eNB 1M determines the uplink transmission power based only on the reception power of the pilot signal received from the UE 2, but is not limited thereto, and is received via each slave cell. You may consider the reception power of a pilot signal. Hereinafter, such a case will be described. 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.

As shown in FIG. 27, 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).

Further, 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).

Subsequently, 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. In this way, 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.

Subsequently, 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).

Thus, by determining the uplink transmission power in consideration of the reception power of the pilot signal received via the slave cell as well as the reception power of the pilot signal received via the master cell, the UE 2 and the group cell 50 Wireless communication can be performed more appropriately.

As described above, some of the embodiments of the present invention have been described in detail with reference to the drawings. However, these are merely examples, and various embodiments can be made based on the knowledge of those skilled in the art including the aspects described in the section of the disclosure of the invention. The present invention can be implemented in other forms that have been modified or improved.

For example, 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.

In the above embodiment, the cell 5 adjacent to the master cell is determined as the slave cell. However, 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.

In the above embodiment, 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. However, the present invention is not limited to this. For example, in eNB1, 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. In such a case, 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.

Further, in the above embodiment, 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. However, 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.

For example, 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

Claims

A plurality of handover processes for securing radio resources for communication with a mobile station and enabling communication with the mobile station when a mobile station and a handover request from the mobile station are received A mobile communication system including a base station of
The mobile station
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 a plurality of base stations, to the base station in the area;
The base station
When receiving the group cell construction request from the mobile station, dependent cell determining means for determining a dependent cell included in a group cell having a cell formed by the local station as a reference cell;
Common resource determining means for determining radio resources for communication with the mobile station, the wireless resources being commonly allocated to the base station forming the dependent cell determined by the dependent cell determining means and the own station When,
Radio resource information transmitting means for transmitting information on radio resources determined by the common resource determining means to a base station forming the dependent cell;
A mobile communication system, comprising: a radio resource determined by the common resource determination means, or a lower layer processing means for securing radio resources based on radio resource information received from a base station forming the reference cell. .
The base station forming the subordinate cell further comprises resource allocation status information transmitting means for transmitting information on free radio resources of the own station as resource allocation status information to the base station forming the reference cell,
The common resource determining means is a free radio resource common to the base station forming the dependent cell and the own station based on the resource allocation status information received from the base station forming the dependent cell and the resource allocation status information of the own station. The mobile communication system according to claim 1, wherein the mobile communication system is determined as a radio resource to be commonly allocated to a base station and a local station forming the subordinate cell.
The base station that forms the reference cell, when the communication quality between the subordinate cell having the highest communication quality with the mobile station and the mobile station is higher than the communication quality between the mobile station and the reference cell, The base station forming the cell is further transmitted with a request to change the subordinate cell to the reference cell, and further includes reference changing means for changing the reference cell formed by the own station to the subordinate cell. The mobile communication system according to claim 1, characterized in that:
When the base station that forms the subordinate cell receives a pilot signal from the mobile station, the base station that forms the reference cell transmits received power information indicating the received power of the pilot signal to the base station that forms the reference cell. Further comprising
The reference changing means is configured such that the highest received power among the received power represented by the received power information received from the base station forming the dependent cell via the dependent cell is determined by the mobile station via the reference cell. When the received power of the pilot signal received from the base station is higher than the received power information indicating the highest received power, a request to change the subordinate cell to the reference cell is transmitted to the base station that has transmitted the received power information representing the highest received power. 4. The mobile communication system according to claim 3, wherein a reference cell formed by the own station is changed to a subordinate cell.
Each of the base stations, when receiving a pilot signal from the mobile station, further comprises received power information transmitting means for transmitting received power information representing the received power of the pilot to the base station forming the reference cell,
The base station that forms the reference cell includes a subordinate changing unit that changes subordinate cells included in the group cell based on the position of the mobile station estimated from the received power represented by the received power information acquired from each base station. The mobile communication system according to claim 1, further comprising:
Each said base station
Upper layer processing means for receiving data to be transmitted to the mobile station from an upper device, performing predetermined processing on the received data, and transmitting the received data;
A transmission timing determination means for determining a transmission timing when data received from the upper layer processing means is transmitted to the lower layer processing means;
Data transfer means for transferring data received from the upper layer processing means and information on the transmission timing determined by the transmission timing determination means to the base station forming the dependent cell;
Data to be transmitted to lower layer processing means when the transmission timing of the data determined by the transmission timing determination means or the transmission timing of the data received from the base station forming the reference cell has arrived The mobile communication system according to claim 1, further comprising: a transmission unit.
The mobile station further includes input means for receiving an input operation from a user,
The mobile communication system according to claim 1, wherein the group cell construction request transmission unit transmits the group cell construction request based on an input operation received from the user by the input unit.
The base station further comprises group cell constructable information transmission means for transmitting group cell constructable information indicating that the own station is a base station capable of constructing the group cell to the mobile station,
The group cell construction request transmission means transmits the group cell construction request to the base station when the group cell construction request information is received from a base station that constructs a cell in the area. The mobile communication system according to claim 1.
The base station further comprises signal transmission means for transmitting a pilot signal to the mobile station via the cell of the own station,
The mobile station compares the received power of pilot signals received from the base station forming the reference cell and the base station forming the dependent cell, and the received power of the pilot signal received via the dependent cell is Criteria indicating that if the highest received power is higher than the received power of the pilot signal received via the reference cell, the subordinate cell to which the pilot signal indicating the highest received power is transmitted should be changed to the reference cell. Further comprising reference change request transmitting means for transmitting a change request to a base station forming the reference cell;
When the reference change request is received from the mobile station, the reference change unit changes a dependent cell to which a pilot signal indicating the highest received power is transmitted to a new reference cell based on the reference change request. 4. The mobile communication system according to claim 3, wherein a reference cell formed by the own station is changed to a subordinate cell.
The base station further comprises signal transmission means for transmitting a pilot signal to the mobile station via the cell of the own station,
The mobile station sends a subordinate change request to change subordinate cells included in the group cell based on the position of the mobile station estimated by the received power represented by the received power information acquired from each base station. Dependent change request transmitting means for transmitting to the base station forming the reference cell,
The mobile according to claim 5, wherein when the dependent change request is received from the mobile station, the dependent changing means changes the dependent cell included in the group cell based on the dependent change request. Communications system.
When the subordinate cell determining means receives the group cell construction request from the mobile station, the subordinate cell determining means determines a cell formed by the own station based on the position information of the cell formed by the base station received from the other base station. The mobile communication system according to claim 1, wherein a subordinate cell included in a group cell as a reference cell is determined.
The dependency changing means determines a movement state of the mobile station based on a history of the received power information received from each base station, and includes a dependency included in the group cell according to the determined movement state of the mobile station. The mobile communication system according to claim 5, wherein the number of cells is changed.
The mobile communication system according to claim 1, wherein the common resource determining means determines different transmission power for each reference cell and subordinate cell constituting the group cell.
The base station further comprises signal transmission means for transmitting a pilot signal to the mobile station via the cell of the own station,
When the mobile station receives a pilot signal from a base station that forms the reference cell and a base station that forms the subordinate cell, the mobile station uses received power information indicating the received power of the pilot as a base station that forms the reference cell. Further comprising reception power information transmission means for transmitting to
The mobile communication system according to claim 13, wherein the common resource determination unit changes transmission power determined for each of the reference cell and the subordinate cell based on reception power information received from the mobile station.
The common resource determining means transmits a power control target notification to a predetermined subordinate cell among subordinate cells constituting the group cell,
The lower layer processing means receives the power control target notification from the base station forming the reference cell only from the radio resource determined by the common resource determination means or from the base station forming the reference cell. The mobile communication system according to claim 1, wherein data is transmitted to the mobile station using a radio resource secured based on the received radio resource information.
When receiving a pilot signal from the mobile station, the mobile station further includes reception power information transmitting means for transmitting reception power information indicating reception power of the pilot signal to a base station forming the reference cell,
The said common resource determination means changes the transmission power in case the said mobile station transmits a signal to the said base station based on the received power information acquired from each said base station, The Claim 1 characterized by the above-mentioned. Mobile communication system.
When receiving a handover request from a mobile station, a base station that executes a handover process for securing radio resources for communication with the mobile station and enabling communication with the mobile station,
When receiving from the mobile station a group cell construction request for requesting construction of a group cell, which is a virtually integrated cell formed by a plurality of base stations, the cell formed by the mobile station is defined as a reference cell. Subordinate cell determining means for determining subordinate cells included in the group cell,
Common resource determining means for determining radio resources for communication with the mobile station, the wireless resources being commonly allocated to the base station forming the dependent cell determined by the dependent cell determining means and the own station When,
Radio resource information transmitting means for transmitting information on radio resources determined by the common resource determining means to a base station forming the dependent cell;
A base station comprising: a radio resource determined by the common resource determining means, or a lower layer processing means for securing radio resources based on radio resource information received from a base station forming the reference cell.
The common resource determining means determines the dependent cell based on resource allocation status information received from the base station forming the dependent cell and information on the available radio resources of the base station and the resource allocation status information of the own station. The base station according to claim 17, wherein an empty radio resource common to the base station to be formed and the own station is determined as a radio resource to be commonly allocated to the base station and the own station to form the subordinate cell. Bureau.
An input means for accepting an input operation from a user;
Based on the input operation received from the user by the input means, the base station that is in the area of a group cell construction request for requesting construction of a group cell that is a virtual integration of cells formed by a plurality of base stations, respectively A mobile station comprising group cell construction request transmission means for transmitting to the station.
A plurality of handover processes for securing radio resources for communication with a mobile station and enabling communication with the mobile station when a mobile station and a handover request from the mobile station are received A wireless communication method in a mobile communication system comprising a base station,
The mobile station is
A group cell construction request transmission step for transmitting a group cell construction request for requesting construction of a group cell, which is a cell obtained by virtually integrating cells formed by a plurality of base stations, to the base station in the area;
The base station that has received the group cell construction request,
A subordinate cell determining step of determining subordinate cells included in the group cell with the cell formed by the own station as a reference cell;
The base station that has received the group cell construction request,
A radio resource for communication with the mobile station, a common resource determining step for determining a radio resource to be commonly allocated to a base station and a local station forming the subordinate cell determined in the subordinate cell determining step; ,
The base station that has received the group cell construction request,
A radio resource information transmitting step for transmitting information on the radio resource determined in the common resource determining step to a base station forming the subordinate cell;
The base station that has received the group cell construction request and the base station that forms the subordinate cell,
A radio communication method, comprising: a radio resource determined in the common resource determination step, or a lower layer processing step for securing radio resources based on radio resource information received from a base station forming the reference cell. .