JP2017028741A - Radio base station - Google Patents

Abstract

PROBLEM TO BE SOLVED: To avoid collision between mobile station UEs to which the same C-RNTI has been allocated even if the same C-RNTI is allocated to a plurality of mobile stations in a phantom cell.SOLUTION: A radio base station PhNB#10 is configured to manage a cell #10 (phantom cell) formed by combining a plurality of small cells and comprises an allocation unit 11 configured to allocate a same C-RNTIph to a plurality of mobile stations UE#1 and UE#3 which are separated from each other by a prescribed distance or more in the cell #10.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a radio base station.

  In the LTE (Long Term Evolution) scheme, as illustrated in FIG. 4, the radio base station eNB assigns a C-RNTI (Cell-Radio Network Temporary Identity) to a mobile station UE that performs communication in a subordinate cell. In this configuration, data is transmitted and received (see Patent Document 1).

  The C-RNTI is configured to be assigned to each cell, and in the LTE scheme, as shown in FIG. 4, for the mobile station UE # 1 and the mobile station UE # 2 that perform communication in the same cell #A, Therefore, the same C-RNTI cannot be allocated, and the same is applied to the mobile station UE # 1 (or the mobile station UE # 2) and the mobile station UE # 3 that communicate in different cells # A / # B. C-RNTIs can be assigned.

  Note that the C-RNTI is configured to be assigned in a “Contention based RA (Random Access) procedure” or a handover procedure.

  The radio base station eNB is configured to perform transmission of downlink data and allocation of resources for transmission of uplink data using the C-RNTI allocated to the mobile station UE.

  At the 3GPP “Rel-12 Workshop”, many proposals related to “Small cell enhancement” were received as a topic of FRA (Future Radio Access).

  In such a proposal, a concept related to “Phantom cell” has been studied.

  As shown in FIG. 5, unlike a conventional macro cell, a phantom cell forms a large cell by connecting a large number of “small cells” to cover a wide area. can do.

3GPP TS36.300

  However, as shown in FIG. 6, each cell (macro cell and phantom cell) manages 65535 C-RNTIs and needs to allocate one C-RNTI to each mobile station UE.

  Here, when the coverage area of the phantom cell is widened, the number of mobile stations UE that perform communication within the phantom cell increases, and therefore, there may be a case where the C-RNTI assigned to the mobile station UE within the phantom cell may be exhausted. Is assumed.

  In order to solve such a problem, as shown in FIG. 7, in the macro cell, one C-RNTI is allocated to each mobile station UE, while in the phantom cell, a plurality of mobile stations UE are It is assumed that one C-RNTI is allocated (that is, one C-RNTI is shared by a plurality of mobile stations UE).

  However, when such an operation is performed, there is a problem in that there is a possibility of collision between mobile stations UE to which the same C-RNTI is assigned in the same cell. Here, when such a collision occurs, there is a possibility that the mobile station UE that is not intended by the radio base station eNB may erroneously receive allocation information for the correct mobile station UE.

  Therefore, the present invention has been made in view of the above-described problems, and even when the same C-RNTI is assigned to a plurality of mobile stations in the phantom cell, the same C-RNTI is assigned. It is an object of the present invention to provide a radio base station capable of avoiding a collision between received mobile stations UE.

  A first feature of the present invention is a radio base station configured to manage a phantom cell formed by connecting a plurality of small cells, and is separated by a predetermined distance or more in the phantom cell The gist of the present invention is to include an assigning unit configured to assign the same cell-specific identifier to a plurality of mobile stations.

  As described above, according to the present invention, even when the same C-RNTI is assigned to a plurality of mobile stations in the phantom cell, the mobile stations UE to which the same C-RNTI is assigned are connected to each other. Thus, it is possible to provide a radio base station that can avoid the collision.

1 is an overall configuration diagram of a mobile communication system according to a first embodiment of the present invention. FIG. 3 is a functional block diagram of a radio base station according to the first embodiment of the present invention. 5 is a flowchart showing an operation of the radio base station according to the first embodiment of the present invention. It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art. It is a figure for demonstrating a prior art.

(Mobile communication system according to the first embodiment of the present invention)
With reference to FIG. 1 thru | or FIG. 3, the mobile communication system which concerns on the 1st Embodiment of this invention is demonstrated.

  As shown in FIG. 1, the mobile communication system according to the present embodiment is an LTE mobile communication system, which includes a radio base station PhNB # 10 that manages cell # 10 and a radio base station that manages cell # 1. eNB # 1, radio base station eNB # 2 that manages cell # 2, and radio base station eNB # 3 that manages cell # 3.

  Here, the cell # 10 is a phantom cell formed by connecting a plurality of small cells, and the cells # 1 to # 3 are macro cells.

  As shown in FIG. 1, the coverage area of cell # 10 and the coverage areas of cells # 1 to # 3 are arranged so as to overlap at least partially.

  As shown in FIG. 2, the radio base station PhNB # 10 includes an assigning unit 11, a receiving unit 12, and a transmitting unit 13.

  The assigning unit 11 is configured to assign C-RNTIph to the mobile stations UE # 1 to UE # 3 in the cell # 10.

  For example, the assignment unit 11 is configured to assign the same C-RNTIph (= A) to a plurality of mobile stations UE # 1 / UE # 3 that are separated by a predetermined distance or more in the cell # 10. Yes.

  Here, as illustrated in FIG. 1, when the allocation unit 11 allocates the same C-RNTIph (= A) to the mobile stations UE # 1 / UE # 2 in the cell # 10, the mobile station UE A collision occurs between # 1 and mobile station UE # 2.

  Therefore, the assigning unit 11 is configured to assign different C-RNTIphs to the mobile stations UE # 1 / UE # 2 within the cell # 10.

  Similarly, when the allocation unit 11 allocates the same C-RNTIph (= A) to the mobile station UE # 2 / UE # 3 in the cell # 10, the mobile station UE # 2 and the mobile station UE # A collision with 3 occurs.

  Therefore, the assigning unit 11 is configured to assign different C-RNTIphs to the mobile stations UE # 2 / UE # 3 within the cell # 10.

  On the other hand, since the mobile station UE # 1 and the mobile station UE # 3 are separated by a predetermined distance or more, the allocating unit 11 performs the same C with respect to the mobile stations UE # 1 / UE # 3 within the cell # 10. -Even when RNTIph (= A) is assigned, no collision occurs between the mobile station UE # 1 and the mobile station UE # 3.

  In addition, the allocation part 11 is comprised so that the positional information on the mobile station UE in cell # 10 may be grasped | ascertained.

  Further, for example, the allocating unit 11 may be configured to use the radius of the coverage area of a predetermined cell (for example, cell # 2) as the above-mentioned predetermined distance, or the coverage overlapping the coverage area of the cell # 10. It may be configured to use an average value, a minimum value, or a maximum value of the radius of the coverage area of a predetermined number of cells # 1 to # 3 having areas, or may be configured to use a fixed value. Alternatively, the average value, the minimum value, or the maximum value of the radius of the coverage area of the small cell that configures the cell # 10 may be used.

  Alternatively, the allocating unit 11 may include the number of cells having a coverage area (may be a small cell constituting the cell # 10), the number of sectors, and the number of radio base stations eNB between cells connected to each mobile station UE. Referring to FIG. 5, the above-described assignment may be performed.

  Furthermore, the allocating unit 11 is not limited to the physical distance between the mobile stations UE, but the reception characteristics and capabilities of each mobile station UE, or the traffic status of the cell and the state of the radio base station eNB (for example, the degree of congestion). In consideration of the above, the above-described assignment may be performed.

  Alternatively, the allocating unit 11 determines whether or not the macro cell (or the small cell constituting the phantom cell) to which each mobile station UE is connected is a different sector, or the radio base station eNB to which the mobile station UE is connected is different. It may be configured to assign the same C-RNTIph depending on whether it is a base station.

  The receiving unit 12 is configured to receive various signals from the mobile station UE and the radio base stations eNB # 1 to eNB # 3 in the cell # 10, and the transmitting unit 13 is configured to receive the mobile station UE in the cell # 10. And various signals are transmitted to the radio base stations eNB # 1 to eNB # 3.

  For example, the transmission unit 13 is configured to notify the mobile station UE in the cell # 10 of C-RNTIph allocated by the allocation unit 11.

  Hereinafter, the operation of the radio base station PhNB # 10 according to the present embodiment will be described with reference to FIG.

  As illustrated in FIG. 3, when the radio base station PhNB # 10 detects the occurrence of a trigger for allocating C-RNTIph to the mobile station UE in the cell # 10 in step S101, 10, the same C-RNTIph is allocated to a plurality of mobile stations UE that are separated by a predetermined distance or more.

  In step S102, the radio base station PhNB # 10 assigns different C-RNTIphs to a plurality of mobile stations UE that are not separated by a predetermined distance or more in the cell # 10.

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

  The first feature of this embodiment is a radio base station PhNB # 10 configured to manage a cell # 10 (phantom cell) formed by connecting a plurality of small cells, and the cell # 10 And allocating unit 11 configured to allocate the same C-RNTIph (cell unique identifier) to a plurality of mobile stations UE # 1 / UE # 3 separated by a predetermined distance or more. The gist.

  According to such a configuration, by assigning the same C-RNTIph only to a plurality of mobile stations UE # 1 / UE # 3 separated by a predetermined distance or more in the cell # 10, the mobile station UE # 1 and The occurrence of a collision with the mobile station UE # 3 can be avoided.

  In the first feature of the present embodiment, when there are cells # 1 to # 3 (macro cells) having coverage areas that overlap the coverage area of the cell # 10, the allocating unit 11 sets the cell # as the predetermined distance described above. The same C-RNTIph may be allocated to a plurality of mobile stations UE # 1 / UE # 3 that are separated by a radius of two coverage areas or more.

  According to such a configuration, by using the radius of the coverage area of the macro cell as the above-mentioned predetermined distance, it is possible to more reliably avoid a collision between a plurality of mobile stations UE to which the same C-RNTIph is assigned.

  Note that the same C-RNTI may be allocated between the macro cell and the phantom cell. At that time, the allocation information of the C-RNTImacro of the cells # 1 to # 3 (macrocell) and the C-RNTIph of the cell # 10 (phantom cell) is the radio base stations eNB # 1 to ## that manage the cells # 1 to # 3. 3 and the radio base station phNB # 10 managing the cell # 10 (for example, via the X2 or S1 interface).

  In the first feature of the present embodiment, when there are cells # 1 to # 3 (macro cells) having coverage areas that overlap the coverage area of the cell # 10, the allocating unit 11 sets the cell # as the predetermined distance described above. 10 may be configured to assign the same C-RNTIph to a plurality of mobile stations UE # 1 / UE # 3 that are separated by at least the radius of the coverage area of the small cell that constitutes 10.

  In the first feature of the present embodiment, when there are cells # 1 to # 3 (macro cells) having coverage areas that overlap the coverage area of the cell # 10, the allocating unit 11 uses different macro cells as the predetermined distance. The same C-RNTIph may be assigned to a plurality of mobile stations UE # 1 / UE # 3 connected to

  In the first feature of the present embodiment, when cells # 1 to # 3 (macro cells) having coverage areas overlapping the coverage area of cell # 10 exist, allocator 11 manages cells # 1 to # 3. The same C-RNTIph may be allocated to a plurality of mobile stations UE # 1 / UE # 3 connected to different radio base stations eNB # 1 to # 3.

  In the first feature of the present embodiment, when there are cells # 1 to # 3 (macrocells) having coverage areas that overlap the coverage area of the cell # 10, the allocator 11 connects the macrocells # 1 to # 1 that are connected. It may be configured to assign the same C-RNTIph to a plurality of mobile stations UE # 1 / UE # 3 in which # 3 is a different sector.

  Note that the operations of the mobile stations UE # 1 / UE # 2 / UE # 3 and the radio base stations eNB # 1 / PhNB # 10 described above may be implemented by hardware or by software modules executed by a processor. It may be implemented or a combination of both.

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

  Such a storage medium is connected to the processor so that the processor can read and write information from and to the storage medium. Further, such a storage medium may be integrated in the processor. Such a storage medium and processor may be provided in the ASIC. Such an ASIC may be provided in the mobile stations UE # 1 / UE # 2 / UE # 3 and the radio base station eNB # 1 / PhNB # 10. Further, the storage medium and the processor may be provided in the mobile stations UE # 1 / UE # 2 / UE # 3 and the radio base station eNB # 1 / PhNB # 10 as discrete components.

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

eNB # 1, PhNB # 10 ... wireless base station 11 ... allocation unit 12 ... reception unit 13 ... transmission unit

Claims (6)

A radio base station configured to manage a cell formed by connecting a plurality of small cells,
A radio base station comprising an assigning unit configured to assign the same identifier to a plurality of mobile stations separated by a predetermined distance or more in the cell.   When there is a macro cell having a coverage area that overlaps the coverage area of the cell, the allocator uses the same identifier as the predetermined distance to a plurality of mobile stations that are separated by a radius of the coverage area of the macro cell. The radio base station according to claim 1, wherein the radio base station is configured to be assigned.   When there is a macro cell having a coverage area that overlaps the coverage area of the cell, the allocating unit determines, as the predetermined distance, a plurality of mobile stations that are separated by a radius of the coverage area of the small cell that constitutes the cell. The radio base station according to claim 1, wherein the radio base station is configured to assign the same identifier.   The allocation unit is configured to allocate the same identifier to a plurality of mobile stations connected to different macro cells when there are a plurality of macro cells having a coverage area overlapping the coverage area of the cell. The radio base station according to claim 1, wherein:   When there is a macro cell having a coverage area that overlaps the coverage area of the cell, the allocator assigns the same identifier to a plurality of mobile stations connected to different radio base stations that manage the macro cell. The radio base station according to claim 1, wherein the radio base station is configured to be assigned.   When there are a plurality of macro cells having a coverage area overlapping the coverage area of the cell, the allocating unit allocates the same identifier to a plurality of mobile stations in which the connected macro cells are different sectors. The radio base station according to claim 1, wherein the radio base station is configured as follows.

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