JP6523153B2 - Wireless access network management device and program - Google Patents

Description

  The present invention relates to a radio access network in which one control device controls one or more base station devices.

  FIG. 6 is a schematic diagram of a Centralized Radio Access Network (C-RAN). In FIG. 6, the control device 51 controls the base station devices 53 and 63, and the control device 71 controls the base station device 73. Base stations 53, 63, and 73 use cells 54, 64, and 74 as their service provision areas, respectively. For example, a signal from a mobile terminal located in the cell 54 is transmitted to a core network (not shown) via the base station apparatus 53 and the control apparatus 51, and a signal to the mobile terminal located in the cell 54 is The signal is transmitted from the core network (not shown) to the control device 51, and the control device 51 transmits the signal to the mobile terminal via the base station device 53.

  In the configuration of FIG. 6, one control device 51 controls the base station devices 53 and 63. Accordingly, the control device 51 can control the base station devices 53 and 63 so as to reduce the interference given to the mobile terminal existing near the boundary between the cell 54 and the cell 64. However, since the base station apparatus 63 and the base station apparatus 73 are controlled by different control apparatuses, the interference given to the mobile terminal existing in the vicinity of the boundary between the cell 64 and the cell 74 is increased.

  Patent Document 1 discloses a configuration in which the connection relationship between a control apparatus and a base station apparatus is dynamically switched in order to reduce handover across the control apparatus in C-RAN. Further, Patent Document 2 discloses a configuration in which the connection relationship between the control device and the base station device is dynamically switched based on the amount of traffic handled by the control device.

Unexamined-Japanese-Patent No. 2013-211783 JP, 2013-77965, A

  The configuration described in Patent Document 1 switches the connection relationship between the control apparatus and the base station apparatus so as to reduce the handover across the control apparatus based on the frequency of inter-cell handover, thereby reducing interference. It is not something that Further, the configuration of Patent Document 2 switches the connection relationship between the control device and the base station device so that the processing load of the control device is not biased, and does not reduce interference.

  The present invention provides a management apparatus and program of a radio access network which can reduce interference given to a mobile terminal.

According to one aspect of the present invention, a management apparatus of a radio access network in which a control apparatus controls one or more base station apparatuses comprises: estimation means for estimating a position of a mobile terminal; and each mobile terminal estimated by the estimation means As clustering means for clustering mobile terminals based on position, grouping means for grouping base station devices based on clusters to which the mobile terminals to be connected belong, and same control device controls base station devices of the same group, A control unit configured to control a connection relationship between the control apparatus and the base station apparatus , wherein the grouping unit sets base station apparatuses to which only mobile terminals belonging to the same cluster connect as the same group, and mobile terminals belonging to different clusters For the base station apparatus to which is connected, the group to which the base station apparatus belongs based on the total number of mobile terminals to be connected per cluster. Wherein the determining.

  According to the present invention, the interference given to the mobile terminal can be reduced.

FIG. 1 is a block diagram of a wireless access network according to one embodiment. FIG. 1 is a block diagram of a wireless access network according to one embodiment. Explanatory drawing of the process in the management apparatus by one Embodiment. Explanatory drawing of the process in the management apparatus by one Embodiment. The block diagram of the management apparatus by one embodiment. A block diagram of a centralized radio access network.

  Hereinafter, exemplary embodiments of the present invention will be described with reference to the drawings. The following embodiment is an exemplification, and the present invention is not limited to the contents of the embodiment. Further, in each of the following drawings, components that are not necessary for the description of the embodiment will be omitted from the drawings.

  FIG. 1 is a block diagram of a C-RAN according to the present embodiment. The control devices 10, 20 and 30 each include a baseband unit (BBU: Base-Band Unit) and a switch (SW), and the BBU of each control device receives a remote radio head (RRH: RRH) via the SW. Connect with Remote Radio Head). The C-RAN of this embodiment performs modulation / demodulation processing in the BBU of the control device, and transmits / receives a signal obtained by digitizing a modulated baseband signal between the BBU and the RRH. Then, the RRH which is a base station apparatus converts a signal transmitted / received to / from the BBU and a wireless signal transmitted / received to / from a mobile terminal in a cell. However, the present invention is not limited to the C-RAN that transmits and receives baseband signals between the control device and the base station device, and one control device controls one or more base station devices, and The controller is also applicable to any form of C-RAN that processes signals transmitted and received by the mobile terminal.

  In the configuration of FIG. 1, the BBU 21 of the control device 20 controls the RRHs 13 and 23 via the SW 22. Further, the BBU 31 of the control device 30 controls the RRH 33 via the SW 32. The RRH 13 provides a service to the cell 14, the RRH 23 provides a service to the cell 24, and the RRH 33 provides a service to the cell 34. In FIG. 1, the BBU 11 does not perform control processing, and is therefore represented by a dotted line. Further, a communication line connecting the SW 12 and the BBU 11 and a communication line connecting the SW 22 and the SW 32 are not used either, and therefore, they are represented by dotted lines. Further, in the present embodiment, a management device 40 capable of communicating with the control devices 10 to 30 is provided.

  A mobile terminal (not shown) measures its received power not only for the connected RRH but also for the RRH which is not connected but can receive radio signals. Then, the mobile terminal uses the identifiers of all RRHs that receive a signal via the connected RRHs and the received power as received power information, and via the connected RRHs with the identification information of its own device, The received power information is transmitted to the BBU controlling the RRH. Each BBU transmits, to the management device 40, received power information reported by the mobile terminal. For example, for a mobile terminal that reported received power for one RRH, the management device 40 is assumed to be located near the center of the cell of that RRH, and for each mobile terminal that reported multiple received powers, The position is determined based on the received power of Then, the management device 40 controls each SW so as to switch the correspondence between the BBU and the RRH so as to reduce the number of mobile terminals located in the vicinity of the boundary between two different BBU cells.

  For example, in the configuration of FIG. 1, it is assumed that there are 20 mobile terminals in the vicinity of the boundary between the cell 14 and the cell 24 and 10 mobile terminals in the vicinity of the boundary between the cell 24 and the cell 34. In addition, it is assumed that it is impossible for a single BBU to control all RRHs due to the restriction of the maximum line length from BBU to RRH. In this case, the configuration of FIG. 1 is maintained. This is because BRH 21 controls RRHs 13 and 23 so that RRHs 13 and 23 serving cell 14 and cell 24 are controlled by the same BBU 21 and interference to mobile terminals near the boundary between cell 14 and cell 24 is reduced. It is because it controls. Thereafter, it is assumed that the mobile terminals move, and there are 10 mobile terminals near the boundary between the cell 14 and the cell 24 and 20 mobile terminals near the boundary between the cell 24 and the cell 34. In this case, the management device 40 switches the configuration of the C-RAN as shown in FIG. In FIG. 2, the BBU 31 controls the RRHs 23 and 33, and the BBU 11 controls the RRH 13. By switching as shown in FIG. 2, the number of mobile terminals that receive interference can be reduced.

  Subsequently, details of processing in the management device 40 will be described using FIGS. 3 and 4. 3 and 4 respectively show 25 cells # 1 to # 25. The cells in FIG. 3 and FIG. 4 are square. Although not shown in FIGS. 3 and 4, RRHs are provided corresponding to the respective cells. Further, in the present embodiment, a control device is also provided corresponding to each cell. In addition, since the cell and the RRH correspond on a one-to-one basis, in the following, the term "cell" is used also in the case of indicating the RRH. That is, for example, although it is the RRH that the BBU controls, it is also used that the BBU controls the RRH and that the BBU controls the cell.

  As described above, the management device 40 receives the received power information together with the identification information of the mobile terminal via the BBU. The management device 40 determines that the mobile terminal that has transmitted the received power information on a single RRH is located near the center of the cell corresponding to that RRH. On the other hand, for mobile terminals that have transmitted received power information related to a plurality of RRHs, their positions are estimated based on the received power from each RRH. The black square in FIG. 3 indicates the position of the mobile terminal estimated by the management apparatus 40 in this manner.

  The management device 40 performs clustering processing such as the k-means method, for example, on the estimated position of the mobile terminal, and groups the mobile terminals into clusters. The mobile terminal group surrounded by the dotted line in FIG. Shows a mobile terminal belonging to That is, in FIG. 3, four clusters 91 to 94 exist. The management device 40 groups cells, that is, RRHs based on a cluster. Specifically, cells in which only mobile terminals belonging to the same cluster exist, that is, RRHs, are in the same group. For example, since cells # 19, # 23, # 24 and # 25 in FIG. 3 have only mobile terminals connected to the same cluster 94, cells # 19, # 23, # 24 and # 25 form one group. Do. The same applies to cells # 4, # 5, and # 10.

  On the other hand, only mobile terminals belonging to cluster 91 exist in cells # 1 to # 3 and # 8, and only mobile terminals belonging to cluster 92 exist in cells # 12, # 13, # 16 and # 17. In cell # 7, there are both mobile terminals connected to the cluster 91 and mobile terminals connected to the cluster 92. In this case, first, the management apparatus 40 sets cells # 1 to # 3 and # 8 as one group # 1, and sets cells # 12, # 13, # 16, and # 17 as one group # 2. Then, for the cell # 7, the management device 40 obtains the number of mobile terminals for each cluster, and belongs to the group having the larger number. For example, in FIG. 3, in the cell # 7, there are two mobile terminals belonging to the cluster 91, and there is one mobile terminal belonging to the cluster 92. Therefore, the management device 40 determines that the cell # 7 belongs to the group # 1, that is, the same group as the cluster 91. Moreover, the management apparatus 40 belongs to the nearest group about the cell in which a mobile terminal does not exist. For example, in FIG. 3, although there is no mobile terminal in the cell # 20, the cell # 2 belongs to the same group as the closest cluster 94.

  FIG. 4 shows a state in which cells are grouped based on the distribution of mobile terminals shown in FIG. The management device 40 controls the SW so that one BBU controls the cells of one group, and sets the connection relationship between the BBU and the RRH. For example, as shown in FIG. 4, cells # 1 to # 3 and cells # 6 to # 8 belong to one group. Therefore, BBUs that control cells # 1 to # 3 and # 6 to # 8 are selected from BBUs corresponding to cells # 1 to # 3 and # 6 to # 8. Hereinafter, this selection method will be described.

  First, the management device 40 determines the reference position based on the positions of the mobile terminals belonging to the same cluster. As the reference position, for example, the barycentric position (centroid) of the cluster calculated by the k-means method, or the central position of the position of the mobile terminal in the cluster can be used. The center position of the mobile terminal in the cluster is the average value of the maximum value and the minimum value of the X coordinates when the position of each mobile terminal is represented by (X, Y) coordinates (or latitude and longitude). The average value of the maximum value and the minimum value of the Y coordinate can be obtained as the value of the Y coordinate. The management apparatus 40 selects the BBU corresponding to the cell including the reference position of the cluster determined in this manner as one to control the cell corresponding to the cluster. For example, when the reference position obtained for the cluster 91 in FIG. 3 is a position in the cell # 2, the BBU corresponding to the cell # 2 is controlled to control the cells # 1 to # 3 and # 6 to # 8. Choose as.

  In the present embodiment, each cell is provided with a control device. However, as for the control device, it is generally less than the number of cells. In this case, the BBU closest to the reference position of each cluster is selected as one to control the cell corresponding to that cluster. Note that, depending on the number of installed control devices, the BBU closest to cells of different groups may be the same. For example, in the group of FIG. 4, the groups of cells # 1 to # 3 and # 6 to # 8 and the BBU closest to the group of cells # 11 to # 13, # 16, # 17, # 21 and # 22 are the same. Can occur. In this case, this BBU can be configured to control two groups of cells.

  As described above, cells are controlled by different BBUs by clustering mobile terminals based on their estimated positions and controlling the same BBU as much as possible for RRHs to which mobile terminals belonging to the same cluster connect. It is possible to reduce the number of mobile terminals existing near the boundary of, and thus to reduce the number of mobile terminals that receive interference.

  FIG. 5 is a block diagram of the management device 40. As shown in FIG. The communication unit 41 communicates with each control device. The estimation unit 42 estimates the position of each mobile terminal based on the received power information received from each mobile terminal via the communication unit 41. The clustering unit 43 performs clustering processing based on the position of each mobile terminal estimated by the estimation unit 42, and classifies each mobile terminal into a cluster. The grouping unit 44 groups the RRHs based on the clusters obtained by the clustering unit 43. The control unit 45 obtains the correspondence between the BBU and the RRH so that the same BBU controls the RRH in the same group, and transmits a control signal for controlling the SW to each control device so as to obtain the obtained correspondence. Do. The database unit 46 has information on cells, information on the installation position of the control device, and information on RRHs to be controlled, and when the control unit 45 selects a BBU that controls RRHs in the same group. Used as information on

  The management device 40 according to the present invention can be realized by a program that causes a computer to operate as the management device 40. These computer programs are stored in a computer readable storage medium or can be distributed via a network.

  42: estimation unit, 43: clustering unit, 44: grouping unit, 45: control unit

Claims (4)

A management apparatus of a radio access network in which a control apparatus controls one or more base station apparatuses,
Estimation means for estimating the position of the mobile terminal;
A clustering unit that clusters mobile terminals based on the position of each mobile terminal estimated by the estimation unit;
Grouping means for grouping the base station apparatus based on a cluster to which the mobile terminal to be connected belongs;
Control means for controlling the connection relationship between the control device and the base station device such that the same control device controls base stations of the same group;
Equipped with
The grouping unit sets base stations connected only to mobile terminals belonging to the same cluster as the same group, and sets base stations connected to mobile terminals belonging to different clusters to the total number of connected mobile terminals per cluster. A management apparatus characterized by determining a group to which the base station apparatus belongs based on the basis . The mobile terminal further comprises, for each of one or more base station apparatuses from which the mobile terminal receives a signal, reception means for receiving reception power information indicating the reception power for each base station apparatus measured by the mobile terminal;
The management apparatus according to claim 1, wherein the estimation unit estimates the position of the mobile terminal based on the received power information measured by the mobile terminal. The management apparatus according to claim 2 , wherein the receiving means receives received power information measured by the mobile terminal from a control apparatus that controls a base station apparatus connected to the mobile terminal. A program causing a computer to function as the management device according to any one of claims 1 to 3 .

Images