WO2014103434A1

WO2014103434A1 - Wireless parameter control device, wireless parameter control device system, wireless parameter control method, and program thereof

Info

Publication number: WO2014103434A1
Application number: PCT/JP2013/073868
Authority: WO
Inventors: 高道井上; 弘人菅原; 航生小林
Original assignee: 日本電気株式会社
Priority date: 2012-12-27
Filing date: 2013-09-05
Publication date: 2014-07-03
Also published as: JPWO2014103434A1

Abstract

In the present invention, when altering wireless parameters of a cell among a plurality of cells, the situation is avoided in which the post-alteration wireless parameters of the cell become inappropriate as a result of the wireless parameters being changed in another cell. A wireless parameter control device that controls the wireless parameters of a cell group takes into consideration the effect of controlling the values of the wireless parameters of another cell in the cell group for each cell of interest among at least one cell to be controlled in the cell group, and predicts the changes in the communication characteristics of the cell group resulting from altering the wireless parameters of the cell of interest. On the basis of the prediction, the values of the wireless parameters of the at least one cell to be controlled in the cell group are controlled.

Description

Wireless parameter control device, wireless parameter control device system, wireless parameter control method and program thereof

The present invention relates to a radio parameter control device, a radio parameter control system, a radio parameter control method, and a program thereof for controlling radio parameters in a radio communication network.

A wireless communication network compliant with a cellular communication system represented by a cellular phone network constitutes a wide service area by distributing a plurality of base stations. Each of the plurality of base stations forms and manages a “cell” that is a range in which the base station itself and a wireless terminal such as a mobile phone can communicate. In general, about one to six cells are formed and managed by one base station.

In addition, during the installation and operation of these base stations, the area incapable of communication (Coverage hole) is reduced, and further, a radio terminal (UE: User Equipment, hereinafter, the radio terminal is appropriately referred to as “UE”) The wireless parameters of the cell are optimized for the purpose of improving the wireless quality and communication quality. Here, specific indexes representing the radio quality include, for example, throughput, abnormal call disconnection rate, handover failure rate, and the like. In addition, as specific indexes representing communication quality, for example, received power, a signal-to-interference ratio, and the like can be given.

When radio parameter optimization is performed, a running test using a dedicated measuring instrument is generally performed in the field, radio wave reception power and interference status, whether call disconnection or handover failure occurs, throughput Etc. are actually measured.

Next, based on the measurement results, identify places where the received power is insufficient (Weak coverage), places where there is strong interference (Pilot pollution), etc., and wireless to solve the problems at these locations Adjust the parameters. Here, as radio parameters to be adjusted, for example, cell antenna tilt angle, antenna azimuth angle, transmission power, handover parameter, and the like are common. Also, adjustment of these radio parameters is usually performed manually.

Optimized cell radio parameters based on the above-described driving test involves manual measurement and tuning work, which contributes to an increase in the operation cost of the radio communication network.

Therefore, in order to reduce the cost for optimization of such radio parameters, development and standardization of a technology for autonomously optimizing the radio parameters of a cell by a base station or the like are being advanced. For example, SON (Self Organizing Network), which is being standardized in 3GPP (3rd Generation Partnership Project), is one example.

One specific example of such a technique is described in Patent Document 1 as “base station apparatus, user apparatus and method used in a mobile communication system”.

In the technique described in Patent Document 1, an object is to easily measure the radio wave propagation state in a specific area in order to optimize the radio parameters of an existing or planned base station. And in patent document 1, in order to solve this subject, the radio | wireless parameter of a base station is adjusted by analyzing the report content of the report signal received from one or more user apparatuses (for example, mobile telephones). The analysis of the report content may be performed by the base station device or may be performed by a node higher than the base station (for example, MME / UPE (Mobile Management Entity / User Plane Entity)).

As described above, in the technique described in Patent Document 1, the user apparatus and the base station cooperate to adjust the radio parameters of the base station without performing on-site measurement manually.

In addition, another specific example of the technique for autonomously adjusting the radio parameters is disclosed in Patent Document 2 as “a method for optimizing cell radio parameters for load distribution”.

In the method disclosed in Patent Document 2, first, the traffic load of a certain cell (referred to as cell A) is measured. When the traffic load of the cell A is higher than a predetermined value, a cell (referred to as cell B) having a large overlapping range with the cell A is selected from the cells having a low traffic load around the cell A. To do.

Then, the coverage of the cell B is expanded and the coverage of the cell A is reduced. On the other hand, when the traffic load of the cell A is low, the coverage of the cell B is reduced and the coverage of the cell A is expanded. The above control is sequentially executed between all the cells.

In the technique disclosed in Patent Document 2, by performing such an operation, radio parameters of each cell are adjusted, and load distribution is achieved among the cells.

JP 2008-172380 A International Publication No. 2000/072618 Pamphlet

By using the techniques described in Patent Document 1 and Patent Document 2 as described above, a certain degree of effect can be expected for autonomous wireless parameter adjustment in the system that does not require manual labor.

However, in a general method including the techniques described in Patent Document 1 and Patent Document 2, when determining the radio parameters for a certain cell, the radio parameters of other cells other than the certain cell are changed. There was a problem of not considering the change in the communication environment caused by. For example, in the technique described in Patent Document 2, the relationship with the cell B is taken into account when adjusting the radio parameter of the cell A, but the radio parameter of the cell B is also adjusted thereafter. Not done. That is, it is not considered that the radio parameter of cell B considered at the time of adjustment in cell A is changed at the time of adjustment in cell B later.

As described above, since the radio parameter is determined independently for each cell without considering the change of the communication environment caused by the change of the radio parameter of another cell, the radio parameter of the cell becomes an inappropriate value. As a result, there is a problem that communication quality is deteriorated due to a change in radio parameters.

More specifically, in these general methods, even after the communication environment changes due to the change of radio parameters of other cells, or the communication environment changes due to the change of radio parameters in the near future. Even in the case of reliable, the wireless parameter is determined using the measurement information including the measurement information before the change of the communication environment. As a result, the radio parameter of the cell is determined to be an inappropriate value, and there is a possibility that the communication characteristics are deteriorated by changing the radio parameter.

The above-described problem will be described with reference to specific examples shown in FIGS.

In the following description, a cell having a relatively wide call area that provides a call area with a radius of several hundred meters to a few dozen kilometers is called a “macro cell”. On the other hand, a cell having a relatively narrow communication area compared to a macro cell is called a “pico cell”. In general, the picocell is provided in a place where the radio wave intensity that cannot be covered by the macrocell alone, such as the basement or the back of a building, tends to be weak.

As shown in FIG. 12, the wireless communication network in this example includes a base station 1000, a small base station 2000, and a small base station 3000. Further, in this example, the macro cell 1001, the pico cell 2001, and the pico cell 3001 are included as cells managed by each base station.

Here, it is assumed that the macro cell 1001 has a low traffic load and the pico cell 2001 and the pico cell 3001 have a high traffic load and the like.

In such a situation, when the method disclosed in Patent Document 2 is applied, the pico cell 2001 and the pico cell 3001 execute load distribution without considering the change of the communication environment caused by the change of the mutual radio parameter. For example, as illustrated in FIG. 13, the small base station 2000 and the small base station 3000 reduce the transmission power of the pico cell 2001 and the pico cell 3001, thereby reducing the coverage of each cell. The reduced cells are represented as a pico cell 2002 and a pico cell 3002.

As a result of the load distribution being simultaneously performed by the two pico cells in this way, the load on the macro cell 1001 increases rapidly, and the communication characteristics in the macro cell 1001 deteriorate.

However, as described above, in general technology, no consideration is given to the load of the macro cell 1001 after execution of load distribution, and even if it is considered, only the load of the macro cell 1001 before execution of load distribution is considered. Therefore, it has not been possible to prevent such problems from occurring.

Therefore, in the present invention, when the radio parameter of a certain cell in a plurality of cells is changed, the radio parameter after the change of the certain cell is inappropriate due to the change of the radio parameter in another cell. It is an object of the present invention to provide a wireless parameter control device, a wireless parameter control device system, a wireless parameter control method, and a program thereof that can avoid the situation.

According to a first aspect of the present invention, there is provided a radio parameter control apparatus for controlling radio parameters for a cell group, wherein each target cell included in one or more control target cells in the cell group Predicting means for predicting a change in communication characteristics in the cell group due to a change in the radio parameter of the cell of interest, while taking into account the effect of control on the value of radio parameters of other cells in the cell group; There is provided a radio parameter control device comprising: control means for controlling radio parameter values of one or more of the control target cells in the cell group based on prediction by a prediction means.

According to a second aspect of the present invention, there is provided a radio parameter control method for controlling radio parameters for a cell group, wherein for each target cell included in one or more control target cells in the cell group, A prediction step for predicting a change in communication characteristics in the cell group due to a change in the radio parameter of the cell of interest while considering the influence of control on the value of the radio parameter of another cell in the cell group; A radio parameter control method comprising: a control step of controlling radio parameter values of one or more of the cells to be controlled in the cell group based on prediction by a prediction step.

According to a third aspect of the present invention, there is provided a radio parameter control program for causing a computer to function as a radio parameter control device that controls radio parameters for a cell group, wherein the computer is connected to one of the cell groups. With respect to each target cell included in one or more control target cells, the effect of the control on the radio parameter value of another cell in the cell group is considered, and the cell A prediction unit that predicts a change in communication characteristics in a group; and a control unit that controls a value of a radio parameter of one or more of the control target cells in the cell group based on the prediction by the prediction unit. A wireless parameter control program that functions as a wireless parameter control device is provided. It is.

According to a fourth aspect of the present invention, there is provided a radio parameter control system comprising a base station that performs radio communication with a terminal, and a radio parameter control device connected to the base station, the base station comprising: Report means for reporting to the base station the quality related to the radio communication measured based on the communication with the terminal, and changing the radio parameters for the cells under the base station according to the change value instruction of the radio parameter control device The wireless parameter control device according to any one of claims 1 to 9, wherein the wireless parameter control device is a wireless parameter control device according to any one of claims 1 to 9, wherein the prediction unit and the control unit are based on a report content by the reporting unit. And instructing the base station to change the radio parameter based on the change value of the radio parameter determined by the control means. Radio parameter control system is provided, wherein.

According to a fifth aspect of the present invention, there is provided a radio parameter control method performed by a system comprising: a base station that performs radio communication with a terminal; and a radio parameter control device connected to the base station. 19. A reporting step in which a station reports quality related to wireless communication measured based on communication with the terminal to the base station, and the wireless parameter control device according to any one of claims 10 to 18 An apparatus for performing a method, wherein the prediction step and the control step are performed based on a report content of the report step, and a radio parameter is changed based on a change value of the radio parameter determined by the control step. Issuing an instruction to the base station, and the base station is subordinate to the base station in response to an instruction of a change value of the radio parameter control device. Radio parameter control method characterized by comprising a changing step of changing the wireless parameters for the cell, it is provided.

According to the present invention, when the radio parameter of a certain cell in a plurality of cells is changed, the radio parameter after the change of the certain cell is inappropriate due to the change of the radio parameter in another cell. It becomes possible to avoid becoming.

It is a block diagram showing the fundamental structure of the radio | wireless communications system concerning Embodiment 1 and Embodiment 2 of this invention. It is a block diagram showing the fundamental structure of the radio | wireless parameter control apparatus, base station, and UE to which Embodiment 1 and Embodiment 2 of this invention are applied. It is a flowchart showing the flow which performs control of the radio | wireless parameter to which Embodiment 1 and Embodiment 2 of this invention are applied. It is a flowchart showing the flow which performs control of the radio | wireless parameter to which Embodiment 1 of this invention is applied. It is a block diagram showing the cell structure of Example 1 in Embodiment 1 of this invention. It is a matrix figure showing the communication characteristic prediction method of Example 1 in Embodiment 1 of the present invention. It is a matrix figure showing the communication characteristic prediction method of Example 2 in Embodiment 1 of the present invention. It is a matrix figure showing the communication characteristic prediction method of Example 3 in Embodiment 1 of the present invention. It is a matrix figure showing the communication characteristic prediction method of Example 4 in Embodiment 1 of this invention. It is a flowchart showing the flow which performs control of the radio | wireless parameter to which Embodiment 2 of this invention is applied. It is a matrix figure showing the communication characteristic prediction method of Example 5 in Embodiment 2 of the present invention. It is a figure (1/2) explaining the subject which this invention tends to solve. It is a figure (2/2) explaining the subject which this invention tends to solve.

Next, an embodiment of the present invention will be described in detail with reference to the drawings. The present invention can be realized by at least two embodiments, the first embodiment and the second embodiment. In this respect, since the constituent elements of the first and second embodiments have many common parts, in this explanation, the common parts will be described first, and then each of the first and second embodiments is unique. The operation will be described individually.

Also, in each drawing referred to below, the same reference numerals are given to the same elements, substantially the same elements, and corresponding elements. In the following description, overlapping descriptions are omitted as necessary. Furthermore, although the embodiment described below is a preferred embodiment of the present invention, the scope of the present invention is not limited only to the embodiment described below, and various modifications can be made without departing from the gist of the present invention. It is possible to implement in the form that has been subjected to.

First, referring to FIG. 1, a configuration example of a wireless communication system, which is a configuration common to

Embodiments

1 and 2 of the present invention, is shown. The wireless communication system includes a wireless parameter control device 10 and a plurality of base stations 20.

Each of the plurality of base stations 20 forms and manages a subordinate cell 30. In addition, a plurality of UEs 40 exist in the cell 30, and the base station 20 performs bidirectional wireless communication with the UEs 40 included in the range of the subordinate cell 30. Here, what kind of wireless communication system is compliant is not the gist of the present embodiment, and wireless communication can be realized based on a predetermined wireless communication system.

Each base station 20 is connected to an upper network (not shown). Each base station 20 relays traffic between the UE 40 and the upper network.

The upper network includes a radio access network and a core network. Note that the base station 20 includes a relay base station that relays the radio signal of the cell 30.

Furthermore, as described in the background art section, each base station 20 may manage two or more cells 30. However, in the description of the present embodiment, it is assumed that each base station 20 has only one managed cell 30 in order to simplify the description. Note that this is merely for the purpose of simplifying the description, and is not intended to limit the number of cells under management of the base station in this embodiment to one.

The UE 40 is a terminal that performs radio communication with the host network via the base station 20, and is normally carried by the user and used, but the UE 40 that is used stationary may be included. Specifically, the UE 40 is realized by, for example, a mobile phone or a portable personal computer or a tablet personal computer that performs data communication using a mobile phone network.

The radio parameter control device 10 acquires radio quality information and communication quality information from a plurality of base stations 20, and determines radio parameters for a plurality of cells 30.

Here, the communication quality information acquired from each of the plurality of base stations 20 is information including at least communication quality information measured and stored in each base station 20. On the other hand, the radio quality information acquired from each of the plurality of base stations 20 is information measured by one or more UEs 40 under the base station 20 and reported from the one or more UEs 40 to the base station 20. The information includes at least the radio quality information (UE measurement information) of the UE 40 that has been received.

Here, specific examples of communication quality information include radio link abnormal disconnection rate (Radio Link Failure) Rate), call abnormal disconnection rate (Call Drop Rate), handover failure rate (Handover Failure Rate), traffic load, average user Examples include throughput and cell throughput.

Specific examples of the radio quality information (UE measurement information) include radio quality for each cell 30 measured by the UE 40, for example, received power of a downlink pilot signal or a reference signal, SINR (Signal toInterference plus Noise Ratio), etc. Signal to noise interference ratio.

For example, taking wireless communication conforming to LTE (Long Term Evolution) as an example, RSRP (Reference Signal Received Power) and RSRQ (Reference Signal Received Quality) are examples of radio quality information.

Further, the radio quality information includes the throughput for each UE 40, communication quality such as BLER (Block Error Rate), event information such as the occurrence of abnormal disconnection or handover failure, the time when the UE measured the radio quality, the measured cell 30 Information such as an identifier and an identifier of the UE 40 may be included.

On the other hand, the radio parameters determined by the radio parameter control device 10 include handover parameters such as an antenna tilt angle, an antenna azimuth angle, transmission power, and CIO (Cell Individual Offset) for each cell.

The specific examples of the communication quality information, the radio quality information, and the radio parameters are merely examples, and the communication quality information, the radio quality information, and the radio parameters may further include items other than those exemplified. Items other than those exemplified may be substituted for the communication quality information, the radio quality information, and the radio parameters.

Next, configuration examples of the radio parameter control device 10, the base station 20, and the UE 40 that are common to the first and second embodiments of the present invention will be described with reference to the block diagram of FIG. In addition, only the component relevant to this embodiment of the base station 20 and UE40 shown in FIG. 2 is shown. Although not shown, the base station 20 includes components for causing the base station 20 to function as a base station. Similarly, although not shown, the UE 40 includes components for causing the UE 40 to function as the UE 40.

The UE 40 includes a communication unit 41 and a radio quality measurement unit 42.

The communication unit 41 receives a pilot signal (pilot signal) and / or a reference signal (reference signal) transmitted from the base station. The signal received by the communication unit 41 is input to the radio quality measurement unit 42. Then, the radio quality measurement unit 42 measures information defined as a measurement target as radio quality information based on the pilot signal and / or the reference signal. The measured wireless quality information is transmitted to the base station 20 via the communication unit 41. Note that the timing of measurement and transmission of radio quality information can be arbitrarily set, and may be executed, for example, in response to a request from the base station, and automatically at a predetermined cycle or a predetermined time. It may be executed at a later time, or may be executed when a handover or power-on is performed.

The base station 20 includes a communication unit 21, a communication quality measurement unit 22, a quality management unit 23, and a radio parameter adjustment unit 24.

The communication unit 21 receives the radio quality information transmitted from the UE 40 and inputs it to the quality management unit 23. Further, the communication unit 21 inputs information related to the communication status to the communication quality measurement unit 22 as information for measuring the communication quality. The information on the communication status varies depending on the communication quality information defined as the measurement target, but includes information indicating the presence / absence of abnormal disconnection of a radio link or call and information for calculating a traffic load, for example.

The communication quality measuring unit 22 measures the communication quality based on the information regarding the communication status input from the communication unit 21, and generates communication quality information indicating the communication quality. Then, the communication quality information is input to the quality management unit 23. The measurement timing of the communication quality measuring unit 22 can be arbitrarily set similarly to the wireless quality measuring unit 42.

The quality management unit 23 manages at least the wireless quality information input from the communication unit 21 and the communication quality information input from the communication quality measurement unit 22. The wireless quality information and the communication quality information are input to the quality information storage unit 11 of the wireless parameter control device 10.

The radio parameter control device 10 includes a quality information storage unit 11, an affected cell determination unit 12, a communication characteristic prediction unit 13, and a radio parameter determination unit 14.

The quality information storage unit 11 collectively stores the wireless quality information and communication quality information acquired from the plurality of base stations 20. The stored radio quality information and communication quality information are appropriately referred to and used by each unit included in the radio parameter control apparatus 10. Specific usage methods of the wireless quality information and communication quality information in each unit will be described later together with the description of each unit.

The affected cell determination unit 12 determines an “affected cell” based on the wireless quality information and the communication quality information stored in the quality information storage unit 11.

Here, an affected cell is defined as a cell that is affected by a certain level or more of the communication characteristics by changing a radio parameter of a certain cell.

For example, when the communication characteristics of a cell B that is a cell other than a certain cell A are affected by a certain level or more by changing a radio parameter of a certain cell A, “cell B is an affected cell of cell A” is there. A method for determining the influence cell will be described later. For example, when changing the radio parameter of the cell A, the communication characteristics of the cell A itself are naturally affected by a certain level or more. Therefore, “cell A is an affected cell of cell A”. For this reason, in the prediction of the change in the communication characteristics accompanying the change of the radio parameter performed at the time of the cooperation control, the change in the communication characteristics of the cell A itself is also taken into consideration.

Furthermore, the affected cell determination unit 12 inputs the affected cell identification information indicating the determined affected cell to the communication characteristic prediction unit 13.

The communication characteristic prediction unit 13 first determines the “cooperation group” by using the wireless quality information and communication quality information stored in the quality information storage unit 11 and the affected cell identification information input from the affected cell determination unit 12. To do. Further, the “cooperation group” is composed of one or more cells, and is also referred to as a “cell group”.

Here, the “cooperation group” is defined as a group of a plurality of cells to be subjected to “cooperation control”.

“Coordination control” refers to determination and change of radio parameters for a certain cell in a cooperation group in consideration of changes in communication characteristics due to changes in radio parameters of one or more other cells belonging to this cooperation group. Say, to do.

As a specific example of cooperation control, when changing radio parameters of a plurality of cells in a cooperation group at the same time (or within a certain period), change of radio parameters of other cells in the cooperation group is considered for each cell. Then, there is control (hereinafter referred to as “other cell consideration control”) that determines the radio parameter of the target cell in the cooperation group.

Further, as another specific example of the cooperation control, when a wireless parameter of a certain cell in the cooperation group is changed, other cells in the cooperation group do not change the wireless parameter for a certain period of time (hereinafter, referred to as “control”). Will be referred to as exclusive control).

By performing cooperative control as described above for cells belonging to the cooperative group, it is possible to increase the improvement effect by controlling the radio parameters. An example of a method for determining a cooperation group will be described later.

Next, the communication characteristic prediction unit 13 predicts the communication characteristic of the cell after changing the radio parameter of the cell. Specifically, the communication characteristic predicting unit 13 determines each of the radio parameters after changing the radio parameters in the cooperation group based on the wireless quality information and the communication quality information stored in the quality information storage unit 11 and the determined identification information of the cooperation group. Predict cell communication characteristics. Here, a method for predicting communication characteristics will be described using one specific example.

In this specific example, the reception power (RSRP) for each radio cell measured by the UE 40 is used as the radio quality information stored in the quality information storage unit 11. Then, the transmission power of the control target radio cell is used as the radio parameter. That is, the throughput for each candidate value of the transmission power of the control target radio cell is predicted for each UE 40 based on the received power (RSRP).

First, the received power (RSRP [dBm]) for each radio cell included in the radio quality information measured by the “prediction target UE” that is the UE 40 that is the target of throughput prediction this time,
(RSRPs, RSRPn1, RSRPn2, ..., RSRPni)
far. Here, RSRPs represents RSRP of a “control target radio cell” that is a cell for determining radio parameters. RSRPn1, RSRPn2,..., RSRPni represent the RSRP of each affected cell from the affected cell 1 to the affected cell i.

First, the RSRP for each radio cell is predicted when it is assumed that the transmission power of the control target radio cell is changed from the current Pr [dBm] to the candidate value Pc [dBm]. For example, assuming that only the RSRP (RSRPs) of the control target radio cell changes by the change amount of the transmission power,
(RSRPs- (Pr-Pc), RSRPn1, RSRPn2,..., RSRPni)
Can be predicted as Note that when other cell consideration control is performed, there are a plurality of control target radio cells, and therefore, all the plurality of control target radio cells change by the amount of change in the respective transmission power.

Next, the prediction results are rearranged in descending order, and the RSRP unit is converted from a decibel value (dBm) to a real value (mW).
(S1, I1, I2, ..., Ini)
far. At this time, since the radio cell corresponding to S1 is the radio cell having the highest RSRP when it is assumed that the transmission power of the control target radio cell is changed, the “prediction target UE” of the case where the transmission power is changed It can be regarded as a connected radio cell. Note that S1 is not necessarily the same cell as the cell to which the “prediction target UE” currently belongs. That is, the “prediction target UE” may remain belonging to the same cell when the transmission power of the control target radio cell is changed, or when switching the destination to another cell, that is, when performing handover There is also a possibility.

SINR when assuming that the transmission power of the control target radio cell is changed to the candidate value Pc [dBm] is
SINR = S1 / (I1 + I2 +... + Ini + NOISE)
Can be predicted as Note that NOISE represents thermal noise [mW]. For the following explanation, the result of converting the above SINR into a decibel value (dB) is set as SINR ′.

The throughput (TP), which is the communication quality of the “prediction target UE” predicted when the transmission power of the control target radio cell is changed to the candidate value Pc [dBm], is well known to those skilled in the art. Using,
TP = B × log2 (1 + SINR ′) × α
Can be predicted as Here, B is the system bandwidth [Hz], and α is a constant representing the amount of deterioration from the theoretical limit that occurs depending on the implementation of the receiver.

In this way, the communication characteristics of the affected cell for each transmission power candidate value of the control target radio cell can be predicted for each “prediction target UE” based on the received power (RSRP).

In this embodiment, all the UEs 40 included in the affected cell are calculated as “prediction target UEs”, and the throughput of each UE 40 when the transmission power of the control target radio cell is changed is predicted. Can do.

And various indexes can be calculated based on this prediction. For example, 5% throughput in the UE 40 connected to the affected cell (when the user throughputs of all UEs 40 connected to the affected cell are arranged in descending order, the throughput of the user corresponding to the lower 5% (for example, the position of the rank of the lower 5%) For example, the average throughput of all users included in the lower 5%)). A specific method of using the calculated index will be described later.

In the above description, it is assumed that each UE 40 belongs to a radio cell having the highest RSRP. However, it is also conceivable that the number of UEs 40 that can be connected simultaneously is imposed on each radio cell. In such a case, the UE 40 that satisfies the number restriction is calculated by the above-described method, and the UE 40 that exceeds the number restriction is assumed to belong to, for example, the second radio cell with the highest RSRP. . That is, it is not predicted as “SINR = S1 / (I1 + I2 +... + Ini + NOISE)” as described above, but is predicted as “SINR = I1 / (S1 + I2 +... + Ini + NOISE)”. It should be noted that which UE 40 can be preferentially attributed to the radio cell with the highest RSRP may be determined according to the mounting environment.

Furthermore, the communication characteristic prediction unit 13 inputs the communication characteristic prediction result to the wireless parameter determination unit 14.

Note that when the communication characteristic prediction unit 13 predicts the communication characteristic, it may be necessary to distinguish whether each cell belonging to the cooperation group is a macro cell or a pico cell. When such distinction is necessary, for example, a method that enables distinction is used as described below.

For example, a PCI (Physical Cell ID) area is divided into a macro cell and a pico cell in advance. By doing so, the communication characteristic prediction unit 13 can distinguish whether each cell is a macro cell or a pico cell by referring to the PCI.

Or, since there is information representing the cell types Large, Medium, and Small as data of the radio station, it is possible to distinguish whether each cell is a macro cell or a pico cell by using the information. It becomes possible.

In this embodiment, the macro cell and the pico cell are called, but this is only an example, and for example, the pico cell may be called a nano cell. Further, the cell may be divided into more cells instead of being divided into two like the macro cell and the pico cell.

The wireless parameter determination unit 14 uses the wireless quality information and the communication quality information stored in the quality information storage unit 11 and the communication characteristic prediction result input from the communication characteristic prediction unit 13, and uses each of the cooperation groups. Determine the radio parameters for each cell. A wireless parameter determination method will be described later.

Next, a radio parameter control method by the radio parameter control apparatus 10 according to the first and second embodiments of the present invention will be described with reference to the flowchart of FIG.

First, in step S100 to step S103, a cell to be subjected to cooperation control, that is, a cell included in the cooperation group is determined.

In this example, N (N is an integer of 2 or more) cells 30 exist as candidate cells included in the cooperation group. These candidate cells 30 may be all or some of the cells 30 managed by the radio parameter control apparatus 10. That is, all or some of the plurality of cells 30 managed by the radio parameter control apparatus 10 are candidates, and then a cooperation group is determined by narrowing down those candidates.

First, for the cells 30-1 to 30-N, it is determined whether each cell 30 itself satisfies the radio parameter control conditions (steps S100-1 to S100-N).

For this determination, for example, communication quality information of the cell 30 is used. Specifically, the average throughput, traffic load, abnormal call disconnection rate, etc. of each cell 30 are used. Then, when the communication quality in each cell 30 is worse than a predetermined standard, it is determined that the wireless parameter control condition is satisfied. For example, among these exemplified standards, the standard such as traffic load and abnormal call disconnection rate indicates that the higher the value is, the worse it is. Therefore, if such a criterion is employed, it is determined that the wireless parameter control condition is satisfied when the value is equal to or greater than the threshold value. On the contrary, among these exemplified criteria, the average throughput indicates that the value decreases as the value decreases. Therefore, if such a criterion is employed, it is determined that the wireless parameter control condition is satisfied when the value is equal to or less than the threshold value.

For the cells 30 that satisfy the determinations in steps S100-1 to S100-N (Yes in steps S100-1 to S100-N), the process proceeds from step S101-1 to S101-N, respectively.

On the other hand, for the cell 30 that does not satisfy the determinations of steps S100-1 to S100-N (No in steps S100-1 to S100-N), the process is terminated without changing the radio parameters. That is, cells 30 that do not satisfy the determinations of steps S100-1 to S100-N are not included in the cooperation group and are excluded from the current cooperation control targets.

Hereinafter, description will be made assuming that the cells 30-1 to 30-M (M is an integer of 1 to N) satisfy the above conditions. In FIG. 3, M = N is set for convenience.

Next, the UE 40 connected to the cells 30-1 to 30-M measures the radio quality in order to obtain information for controlling the radio parameters (steps S101-1 to S101-M). The measured radio quality information is reported to the radio parameter control apparatus 10 via the base stations 20-1 to 20-M that manage the cells 30 that satisfy the radio parameter control conditions.

Next, in steps S102-1 to S102-M, the affected cells of each cell 30-i (i = 1 to M) are targeted for the cells 30-1 to 30-M that satisfy the radio parameter control conditions. Set. Here, the cell affected by the cell 30-i is a cell affected by the cell 30-i.

As an influence cell setting method, any setting method can be used. For example, the following methods can be considered.

When setting an influence cell of a certain cell 30-j (j is an integer not less than 1 and not more than M), the cell 30-j itself is always included.

Further, regarding the cells 30 other than the cell 30-j, the transmission power value of the cell 30-j becomes a predetermined transmission power value (for example, a lower limit value of a range changeable by setting or zero). In this case, a cell 30-k (k is an integer of 1 or more and M or less, j ≠ k) expected to be selected as a handover destination by the UE 40 connected to the cell 30-j is set as an affected cell of the cell 30-j.

Alternatively, when the transmission power value of the cell 30-j becomes a predetermined transmission power value, the UE 40 connected to the cell 30-j has a predetermined number (or a predetermined ratio) or more. The cell 30-j that is expected to be selected as the handover destination by the UE 40 may be set as an affected cell of the cell 30-j.

In order to determine an expected cell 30-k to be selected as a handover destination when the transmission power value of the cell 30-j is changed, a report is made to the base station 20 that manages the cell 30-j in S101-j. A method of using the radio quality information of the UE 40 that has been used can be considered. Specifically, it is assumed that each UE 40 connects another cell 30-k with the highest received power of the downlink pilot signal and / or reference signal as a handover destination according to the measurement result from each UE 40.

Thus, the cell 30-k to be connected as the handover destination can be determined from the estimation result of the reception power at the UE 40 when the transmission power value of the cell 30-j is changed.

As another example of the setting method of the affected cell, an example of setting based on the distance between the base station antennas of the base station 20 can be considered. That is, when an affected cell 30-k corresponding to a certain cell 30-j is set, the cell managed by the base station 20 within a predetermined range from the antenna installation position of the base station 20 managing the cell 30-j 30 may be set as the influence cell 30-k of the cell 30-j.

As another example of the setting method of the affected cell, an example of setting based on the number of handover attempts of each UE 40 can be considered. That is, when an affected cell of a certain cell 30-j is set, the number of handover attempts counted in a predetermined period is used, and the cell 30 in which the number of handover attempts from the cell 30-j exceeds a predetermined threshold It may be set as the influence cell 30-k of -j.

As another example of the setting method of the affected cell, an example of setting based on a preset neighboring cell list can be considered. That is, when an affected cell of a certain cell 30-j is set, the neighbor cell list set as a handover destination candidate from the cell 30-j is used, and all of the cells 30 registered in the neighbor cell list or A part may be set as the influence cell 30-k of the cell 30-j.

Next, in step S103, a cooperation group is set based on the cells 30-1 to 30-M that satisfy the wireless parameter control conditions.

For example, the following method can be considered as a method for setting a cooperation group.

For example, one or more affected cells that are affected by an arbitrary cell, and a method in which the arbitrary cell is set as an affected cell of the own cell, and a set of one or more cells that affect the arbitrary cell is used as a cooperation group Is mentioned. In that case, for example, as described above, it is repeated until the affected cell of the own cell and the cell having the own cell as the affected cell are not added to the linked group, and the linked group at that time is finally determined as the linked group To do.

Specifically, first, a certain cell 30-A is selected, a cell 30-B that is an affected cell of the cell 30-A is searched from the cell 30-A as a base point, and the cell 30-A is selected as an affected cell. The cell 30-C is searched. The cell 30-B and the cell 30-C thus searched are added to the members of the cooperation group.

Next, the same search is performed using the added cell 30-B or cell 30-C as a base point. These processes are repeated until there is no corresponding cell 30, and a cooperation group is formed by all the cells 30 that finally become members.

For example, when one or more linkage groups are formed, an additional linkage group is formed starting from a cell that is not included in those linkage groups.

Another example of a method for setting a cooperation group is a technique of forming a cooperation group in units of macro cells in a network configuration in which macro cells and pico cells are mixed as the cells 30. Specifically, for each of one or more pico cells, if the only macro cell included in one or more affected cells of the pico cell is a macro cell, the one or more pico cells are Shall belong to the cooperation group. On the other hand, for each of the one or more pico cells, when there are a plurality of macro cells included in the one or more affected cells of the pico cell, the macro cell having the greatest influence is selected from the plurality of macro cells. Then, it is assumed that one or more pico cells sharing the selected macro cell and the common macro cell belong to one cooperation group.

Further, as another example of the method for setting the cooperation group, in the network configuration in which the macro cell and the pico cell are mixed as the cell 30, a technique of forming a cooperation group in units of pico cells is also provided, contrary to the above example.

Specifically, for each of one or more macro cells, if the only pico cell included in the one or more affected cells of the macro cell is a certain pico cell, these one or more macro cells are the certain pico cell. Shall belong to the cooperation group. On the other hand, for each of one or more macro cells, when there are a plurality of pico cells included in one or more affected cells of the macro cell, the pico cell having the greatest influence is selected from among the plurality of pico cells. It is assumed that one or more macro cells sharing the selected pico cell and the common pico cell belong to one cooperation group.

As still another example of the method for setting a cooperation group, information on the installation position of a cell stored in an operation management device (not shown) or the like as wireless station data is used to connect adjacent cells with a cooperation group. The technique to do is mentioned. Specifically, a clustering method such as a k-nearest neighbor method (k-NN: k-nearest neighbor algorithm) can be used.

Note that the cooperation group may be a range of the cells 30 limited by the above method, or may be all of the cells 30 managed by the wireless parameter control device 10. That is, step S100 to step S103 may be omitted, and all the cells 30 managed by the radio parameter control apparatus 10 may be handled as one cooperation group.

Suppose that g linked groups (g is an integer of 1 or more) are set by the linked group settings. That is, it is assumed that cooperation group 1 to cooperation group g are set.

The subsequent processing is processing for each cooperation group. In FIG. 3, steps S104-1,..., Step S104-g are illustrated, but this assumes that there are a plurality of linkage groups. In the present embodiment, there may be only one cooperation group. If there is only one cooperation group (that is, when g = 1), only step S104-1 is performed.

Subsequently, in step S104-h (h = 1 to g), the communication characteristics when the radio parameters of each cell 30 in the h-th cooperation group set in step S103 are changed are predicted. Then, the radio parameter of each cell 30 is set to a value predicted that the communication characteristics in the h-th cooperation group are optimized.

The communication characteristics referred to here are, for example, traffic load, resource utilization, effective number of scheduling users, user throughput, cell throughput, reception quality (RSRP, RSRQ, SINR) and the like.

Further, instead of calculating the communication characteristics using both the radio quality information and the communication quality information, the communication characteristics may be calculated using only one of the radio quality information and the communication quality information.

The contents described above are common contents in the first and second embodiments. Subsequently, Embodiment 1 and Embodiment 2 will be described individually. In addition, since the specific operation for predicting communication characteristics in steps S104-1 to S104-h varies depending on each embodiment, it will be described in detail in the following description of the first and second embodiments.

<Embodiment 1>
In the first embodiment, a method for performing other cell consideration control in order to determine and change a radio parameter after considering a change in communication characteristics due to a radio parameter change of another cell in the cooperation group will be described.

A method of controlling each wireless parameter in the cooperation group in the first embodiment will be described with reference to FIG.

FIG. 4 illustrates processing in “cooperation group h” (h is an integer of 1 to g), which is one of the cooperation groups 1 to g.

In step S104-h-1, the communication characteristics when the radio parameters of each cell 30 in the cooperation group h are changed are predicted.

When predicting the communication characteristics when the radio parameter of a certain cell 30 included in the cooperation group h is changed, the radio parameters of other cells 30 other than the certain cell 30 included in the cooperation group h are changed. It is also taken into account.

A specific method for predicting communication characteristics will be described in an embodiment described later.

Next, in step S104-h-2, the radio parameter determination unit 14 determines the radio parameters of each cell so that the communication characteristics after changing the radio parameters are optimized based on the communication characteristics predicted in step S104-h-1. Determine the change value of. Then, the radio parameter determination unit 14 collectively changes the radio parameters of each cell to the determined change value. Thereby, the operation of the present embodiment ends.

According to the first embodiment described above, when determining the radio parameters of each cell in a plurality of cells, the change of communication characteristics caused by the change of the radio parameters of other cells is also taken into consideration, and the plurality of cells It is possible to control the wireless parameters in cooperation with each other.

<Embodiment 2>
In the first embodiment, the method for performing other cell consideration control has been described. However, in the second embodiment, wireless communication is considered in consideration of a change in communication characteristics in an affected cell due to a radio parameter change of another cell in the cooperation group. A method for performing exclusive control in order to determine and change parameters will be described.

A method for controlling each wireless parameter in the cooperation group according to the second embodiment will be described with reference to FIG. G linkage groups are set by the processing up to step S103 described with reference to FIG. FIG. 10 illustrates processing in one set cooperation group h (h is an integer of 1 to g). Here, the value n in FIG. 10 represents the number of cells included in the cooperation group h.

In step S104-h-1, similarly to the first embodiment, the communication characteristics when the radio parameters of each cell in the cooperation group h are changed are predicted.

Next, in step S104-h-3, based on the communication characteristics predicted in step S104-h-1, a cell for changing the radio parameter and a change value of the radio parameter are determined. In the second embodiment, it is assumed that the number of cells whose radio parameters are changed at one time is only one in the cooperation group g.

Next, in step S104-h-4, the radio parameter of the single cell determined in step S104-h-3 is changed to the changed value determined in step S104-h-3. The change here is not a calculation change but an actual setting of the changed radio parameter in the base station related to the cell.

Next, in step S104-h-5, it is determined whether the wireless parameter change completion condition is satisfied. If the completion condition is satisfied (Yes in step S104-h-5), the wireless parameter control is completed.

On the other hand, if the completion condition is not yet satisfied (No in step S104-h-5), the process proceeds to steps S104-h-6-1 to S104-h-6-n.

In steps S104-h-6-1 to S104-h-6-n, in order to control radio parameters at the next control timing, UEs 40 connected to cells 1 to n perform radio quality measurements, respectively. The wireless quality information is reported to the wireless parameter control apparatus 10 via the base station 20 related to .about.n. In addition, the base station 20 that manages the cells 1 to n measures communication quality information and reports the same to the radio parameter control apparatus 10 in the same manner.

When the reporting of the radio quality information and the communication quality information is completed, the radio parameter control device 10 updates the radio quality information and the communication quality information stored in the quality information storage unit 11 based on the report contents. As a result, the processing of steps S104-h-6-1 to S104-h-6-n ends.

Next, the process returns to step S104-h-1. And the radio | wireless parameter control apparatus 10 estimates the communication characteristic in an influence cell at the time of changing the radio | wireless parameter of each cell in the cooperation group h, respectively. The prediction of the communication characteristics is performed based on the radio quality information and communication quality information updated in steps S104-h-6-1 to S104-h-6-n.

Thereafter, Steps S104-h-1 to S104-h-6 are repeated until Yes is obtained in Step S104-h-5. Thereby, the process of step S104-h ends.

When step S104-h-1 to step S104-h-6 are repeated in step S104-h, the radio parameter change is performed for the cell in which the radio parameter has been changed at the previous control timing or the cell that has been determined not to be changed. You may make it exclude from this candidate. The control timing is a timing for updating the radio quality information and communication quality information after changing the radio parameter, and changing the radio parameter again based on the updated radio quality information and communication quality information. That is, it is the timing at which a series of processing from step S104-h-1 to step S104-h-6 is performed once in step S104-h. The control timing may be provided periodically at a predetermined cycle, may be provided at a predetermined time, or may be provided when the wireless parameter control device 10 receives a user instruction. Anyway. By excluding the cell whose radio parameter has been changed, it is possible to avoid repeatedly changing the radio parameter of the same cell before changing the radio parameter of another cell.

As the completion condition used in step S104-h-5, for example, the following completion condition may be used.

For example, the completion of changing the radio parameters of all cells in the cooperation group can be exemplified as the first completion condition. If this first completion condition is adopted, when repeating step S104-h-1 to step S104-h-6 in step S104-h, the cell whose radio parameter has been changed at the previous control timing is used. In addition, a cell that has been determined not to be changed needs to be excluded from radio parameter change candidates.

Further, in step 104-h-4, it can be exemplified as the second completion condition that there is no cell whose communication characteristics improve even if the radio parameter is changed.

In addition, the number of cells that control radio parameters in the cooperation group (or the ratio of cells to be controlled among all the cells in the cooperation group) is determined in advance, and the number of cells that control the wireless parameters (or all cells in the cooperation group) The third completion condition can be exemplified by the fact that the ratio of cells to be controlled to the number of cells) has reached a predetermined number of cells (or the ratio of cells to be controlled to all cells in the cooperation group).

According to the second embodiment described above, based on the actual communication quality characteristic and the actual radio quality characteristic measured after actually changing the transmission power, the actual communication characteristic corresponding to the transmission power after the change is changed. Since the value and the predicted value of the communication characteristic corresponding to the transmission power around the transmission power after the change can be calculated, the transmission power can be controlled more accurately.

Subsequently, Example 1 to Example 4, which are examples of step S104-h according to the first embodiment, will be described. In the following embodiments, the method for predicting communication characteristics in step S104-h-1 is different, but the contents of step S104-h-2 are common. Therefore, in order to avoid redundant description, description of step S104-h-2 is omitted in the description of each embodiment below.

In the first embodiment, communication characteristics are predicted for all combinations of wireless parameter change candidates for a plurality of cells in a cooperation group.

FIG. 5 shows an arrangement example of cells for explaining the first embodiment.

Referring to FIG. 5, in this cell arrangement example, there are one macro cell (macro cell 31) and two pico cells (pico cell 32 and pico cell 33). The macro cell 31 is under the control of the base station 20-1, the pico cell 32 is under the control of the base station 20-2, and the pico cell 33 is under the control of the base station 20-3. In addition, it is assumed that the cells included in the current cooperation group h are only two pico cells (the pico cell 32 and the pico cell 33).

In the description of the first embodiment, the case where the wireless parameter to be changed is transmission power and the predicted communication characteristic is user throughput will be described as an example. Further, although the transmission power can be changed, in the present explanation, it is assumed that each pico cell can be changed in increments of 1 dBm from 36 to 30 dBm.

Next, a method for predicting communication characteristics in the first embodiment will be described with reference to FIG. In the first embodiment, there are 49 combinations of radio parameter candidate values of pico cells (pico cell 32 and pico cell 33) (pico cell 32: seven types of transmission power × pico cell 33: seven types of transmission power). 5% throughput in the UE 40 connected to the affected cell of the pico cell (when the user throughputs of all the UEs 40 connected to the affected cell of both pico cells are arranged in descending order, the throughput of the user corresponding to the lower 5% (for example, the lower 5% The throughput of the users in the ranking position, the average throughput of all the users included in the lower 5%, etc.)).

Here, in the following description, the combination when the transmission power of the pico cell 32 is set to 36 dBm and the transmission power of the pico cell 33 is set to 35 dBm is expressed as “36/35”. To do. Further, when the transmission power of the pico cell 32 is set to 36 dBm and the transmission power of the pico cell 33 is set to 35 dBm, the 5% throughput in the UE 40 connected to the affected cells of both pico cells seems to be 3.5 Mbps. Such a case is expressed as “36/35: 3.5 Mbps”.

In this example, the 5% throughput in each transmission power combination is 36/36: 3.3 Mbps, 35/36: 3.1 Mbps,... 30/36: 3.0 Mbps, 36/35: 3.5 Mbps, 35/35: 3.8 Mbps, ... 30/35: 3.9 Mbps, ..., 36/30: 4.0 Mbps, 35/30: 4.2 Mbps, ..., 30/30 : 4.4 Mbps.

The current transmission power of the pico cell 32 is 36 dBm, the transmission power of the pico cell 33 is 36 dBm, and the corresponding 5% throughput value of 3.3 Mbps is the currently measured communication quality information and the current actual measurement. It is a value calculated based on the radio quality information. Therefore, this 5% throughput value is an actual value. Also, the 5% throughput value corresponding to another combination of the transmission power value of the pico cell 32 and the transmission power value of the pico cell 33 is calculated based on the currently measured communication quality information and the currently measured radio quality information. Estimated value. This may be expressed as a relative value based on 3.3 Mbps, which is a 5% throughput value corresponding to a combination of 36 dBm, which is the transmission power of the current pico cell 32, and 36 dBm, which is the transmission power of the pico cell 33. . This relative value represents the amount of change that will occur if the transmission power is changed.

Therefore, in Example 1, the transmission power of the pico cell 32 and the pico cell 33 is determined to be 30/30 (pico cell 32:30 dBm, pico cell 33:30 dBm) at which the predicted 5% throughput is maximized.

In the first embodiment, the case where the number of cells in the cooperation group is 2 has been described. However, the wireless parameter can be similarly determined even when the number of cells is 3 or more. For example, if the number of cells in the cooperation group is a, a similar method can be used using an a-dimensional table.

Further, although the radio parameter to be controlled is transmission power, other radio parameters such as an antenna tilt angle, an antenna azimuth angle, and a handover parameter may be used. Furthermore, although one type of wireless parameter called transmission power is changed as the wireless parameter to be changed, the wireless parameter to be changed may be a combination of two or more types.

For example, if the number of cells in the cooperation group is a and the number of wireless parameters to be changed is b, a similar method can be used using an a × b dimensional table.

Further, although the throughput is predicted as the prediction of the communication characteristics, other communication characteristics such as the traffic load and the signal-to-noise interference ratio such as SINR may be predicted. When only one communication characteristic to be predicted is viewed, the evaluation amount is a predicted value of the communication characteristic. However, when evaluating predicted values of a plurality of communication characteristics in this way, the evaluation amount is set to the plurality of evaluation values. It is a function of the predicted value of communication characteristics.

Furthermore, although the lower 5% throughput was examined this time, 5% is merely an example, and other values may be used. For example, the lower 3% may be used, or the average value or median value of all UEs 40 connected to the affected cell may be used.

In the above description, if the number of cells in the cooperation group is a, a similar method can be used using an a-dimensional table. This is the case when all combinations from the minimum value to the maximum value of the radio parameter adjustment range for each cell are made. In addition to this, for example, a combination of all radio parameters in a range where the sum of absolute differences from the current radio parameters for each cell is equal to or less than a predetermined value may be set as a change candidate, Any combination of distributions may be used as a change candidate.

In the above description, the range of change candidates includes the current set of wireless parameter values, which is normal, but need not be included. The same applies to the following embodiments.

In the first embodiment, since the communication characteristics in all combinations of wireless parameter candidate values of cells are predicted, it is possible to increase the effect of improving the communication characteristics when a plurality of cells cooperate to change the wireless parameters.

In Example 2, the number of combinations for predicting communication characteristics is limited by sequentially determining wireless parameters for each of a plurality of cells in the cooperation group. In other words, the second embodiment is different from the first embodiment in that the prediction is not performed for all the combinations but only for the limited combinations.

In the following description of the second embodiment, the description will be made using the cell arrangement example shown in FIG. That is, as in the first embodiment, there is one macro cell (31) and two pico cells (pico cell 32 and pico cell 33), and the cells included in the cooperation group are only two pico cells (pico cell 32 and pico cell 33). Take a case as an example.

Also, it is the same as in the first embodiment in that the wireless parameter to be changed is transmission power, the predicted communication characteristic is user throughput, and the transmission power can be changed in increments of 1 dBm from 36 to 30 dBm in each picocell.

Next, a method for predicting communication characteristics in the second embodiment will be described with reference to FIG. In the second embodiment, transmission power is determined for each cell in order from a plurality of cells in the cooperation group. Therefore, in Example 2, it determines from the order of the cell which determines transmission power.

Specific examples of the cell order determination method include, for example, a method of determining transmission power from a cell with a high traffic load, a method of determining from a cell with a high abnormal call disconnection rate, and a cell with a large number of effective scheduling users. The method of determining can be considered. That is, a cell having a large influence due to a change in radio parameters, a cell having poor communication characteristics, or the like is regarded as a cell having a high rank.

For example, it is assumed that a method of determining the order of transmission power determination based on the level of traffic load is adopted. In this case, assuming that the traffic load of the pico cell 32 is 60% and the traffic load of the pico cell 33 is 70%, the traffic load The transmission power is determined from the pico cell 33, which is a high cell.

Therefore, first, the transmission power of the pico cell 32 which is a cell that is not the pico cell 33 is fixed to the initial value of 36 dBm, while the transmission power of the pico cell 33 is kept at 36 dBm, and the transmission power of the pico cell 33 is increased by 1 dBm up to 30 dBm. In each case changed in (5), 5% throughput in all UEs 40 connected to both affected cells is predicted.

In this case, 36/36: 3.3 Mbps, 36/35: 3.8 dBm,..., 36/30: 3.6 dBm, so that the transmission power of the picocell 33 has the maximum predicted 5% throughput. It is determined to be 35 dBm.

In the above description, the initial value of the transmission power of the pico cell 32 is fixed as 36 dBm. This is because the current transmission power value of the pico cell 32 is 36 dBm in this example. That is, in this example, the current value is used as it is as the initial value.

Next, while the transmission power of the pico cell 33 is fixed to the determined 35 dBm, the transmission power of the pico cell 32 having the second rank is kept at 36 dBm, and the transmission power of the pico cell 32 is increased to 30 dBm in 1 dBm increments. In each changed case, 5% throughput in the UE 40 connected to both affected cells is predicted.

In this case, 36/35: 3.8 Mbps, 35/35: 3.9 dBm,..., 30/35: 3.6 dBm, so the transmission power of the pico cell 32 has the maximum predicted 5% throughput. It is determined to be 35 dBm.

Therefore, in the second embodiment, the transmission power of the pico cell 32 is changed from 36 dBm to 35 dBm, and the transmission power of the pico cell 33 is changed from 36 dBm to 35 dBm.

In the second embodiment, (picocell 32: 1 type of transmission power × picocell 33: 7 types of transmission power + picocell 33: 1 type of transmission power × picocell 32: 7 types of transmission power (1 × 7 + 1 × 7)) Throughout 14 patterns, 5% throughput prediction is performed, and it is possible to reduce the number of patterns targeted for throughput prediction compared to the first embodiment (49 patterns). For this reason, it is possible to reduce the amount of calculation associated with throughput prediction.

In Example 2, the transmission power of one cell is uniquely determined from the prediction result of the communication characteristics when the transmission power of one cell is changed. That is, in the above-described example, the transmission power of the pico cell 33 is uniquely determined to be 35 dBm that maximizes the predicted 5% throughput. However, instead of uniquely determining in this way, a method in which a plurality of transmission powers are candidates may be employed. In this case, not only the transmission power with the maximum 5% throughput but also the second and third transmission powers are left as candidates, and the communication characteristics for the combination with the transmission power of the other cell are predicted. Even if this is the case, it is possible to reduce the pattern to be throughput predicted compared to the first embodiment. For example, even if the third transmission power is selected as a candidate (pico cell 32: 1 type of transmission power x pico cell 33: 7 types of transmission power + pico cell 33: 3 types of transmission power x pico cell 32: 7 types of transmission) Throughout 28 patterns of power (1 × 7 + 1 × 7 × 3)), 5% throughput prediction is performed, and it is possible to reduce the number of patterns to be subjected to throughput prediction compared to the first embodiment (49 patterns).

In the above example, the transmission power adjustment range is 30 dBm to 36 dBm, but this adjustment range may be changed. For example, the adjustment range may be expanded, shifted, or the upper limit value and the lower limit value may be changed separately.

In the second embodiment, the case where the number of cells in the cooperation group is 2 has been described. However, the wireless parameter can be similarly determined even when the number of cells is 3 or more.

For example, when the number of cells included in the cooperation group is 3, first, the priority is determined from 1 to 3, and then the transmission power of the cell with the priority 2 and the transmission power of the cell with the priority 3 Are fixed to the current values, and the transmission power of the cell having the priority of 1 is determined so that the communication characteristics are best within a predetermined range. Then, the transmission power of the cell with priority 1 is fixed to the value after determination, the transmission power of the cell with priority 3 is fixed to the current value, and the transmission power of the cell with priority 2 is in a predetermined range. The communication characteristics are determined to be the best. Finally, with the transmission power of the cell with priority 1 and the transmission power of the cell with priority 2 fixed to the determined values, the transmission power of the cell with priority 3 is within a predetermined range. The communication characteristics are determined to be the best. This is the same even when the number of cells included in the cooperation group is four or more.

Further, although the radio parameter to be controlled is transmission power, other radio parameters such as an antenna tilt angle, an antenna azimuth angle, and a handover parameter may be used. Furthermore, although one type of wireless parameter called transmission power is changed as the wireless parameter to be changed, the wireless parameter to be changed may be a combination of two or more types. Further, although the throughput is predicted as the prediction of the communication characteristics, other communication characteristics such as the traffic load and the signal-to-noise interference ratio such as SINR may be predicted. Furthermore, although the lower 5% throughput is illustrated this time, other values may be used. For example, the lower 3% may be used, or the average value or median value of all UEs 40 connected to the affected cell may be used.

In the second embodiment, the communication characteristics in all combinations of the wireless parameter candidate values of each cell are predicted, so that the effect of improving the communication characteristics by changing the wireless parameters in cooperation with a plurality of cells can be increased.

In the second embodiment, for a plurality of cells in a cooperation group, wireless parameters are sequentially determined one cell at a time, thereby reducing the amount of calculation associated with prediction of communication characteristics while maintaining the effect of changing wireless parameters. Can do.

In the first and second embodiments, the radio parameters of each cell are determined at one time by a single determination. However, in the third embodiment, unlike these, a change width to be changed by a single determination is determined in advance, and a plurality of parameters are determined. The radio parameters are determined while repeating the radio parameters of the cells one after another.

Example 3 will also be described using the cell arrangement example shown in FIG. 5, as in Examples 1 and 2. That is, as in the first embodiment, there is one macro cell (31) and two pico cells (pico cell 32 and pico cell 33), and the cells included in the cooperation group are only two pico cells (pico cell 32 and pico cell 33). Take a case as an example.

The same as in the first and second embodiments, in that the wireless parameter to be changed is transmission power, the predicted communication characteristic is user throughput, and the transmission power can be changed in increments of 1 dBm from 36 to 30 dBm in each picocell. To do.

Next, a method for predicting communication characteristics in the third embodiment will be described with reference to FIG. In the third embodiment, similarly to the second embodiment, transmission power is determined for each cell in order from a plurality of cells in the cooperation group. Therefore, also in Example 3, it determines from the order of the cell which determines transmission power.

For example, it is assumed that a method of determining the order of transmission power determination based on the level of traffic load is adopted. In this case, assuming that the traffic load of the pico cell 32 is 60% and the traffic load of the pico cell 33 is 70%, the traffic load The determination of transmission power is started from the pico cell 33 which is a high cell.

In Example 3, the change width for changing the transmission power at a time is 1 dBm. First, while the transmission power of the pico cell 32 is fixed to 36 dBm, the UE 40 that is connected to both affected cells when the transmission power of the pico cell 33 remains 36 dBm and when the transmission power of the pico cell 33 is changed to 35 dBm. Predict 5% throughput. In this case, since 36/36: 3.3 Mbps and 36/35: 3.5 dBm, the transmission power of the pico cell 33 is provisionally determined to be 35 dBm.

Next, the transmission power of the pico cell 33 is fixed to 35 dBm, while the transmission power of the pico cell 32 is kept at 36 dBm, and the transmission power of the pico cell 32 is changed to 35 dBm, and both the affected cells are connected. Predict 5% throughput at UE40. In this case, since 36/35: 3.5 Mbps and 35/35: 3.6 dBm, the transmission power of the pico cell 32 is provisionally determined to be 35 dBm.

In this way, in this embodiment, the wireless parameter to be determined is searched by repeatedly making a temporary determination within the range of the predetermined change width while changing the cell to be changed. A search by repeating such provisional determination is performed until a predetermined end condition is satisfied. Then, for a cell that satisfies a predetermined termination condition, the radio parameter is determined by performing this determination based on a value provisionally determined before the termination condition is satisfied, and the search is terminated. The cell in which this determination has been made is excluded from the subsequent search targets.

Here, for example, a condition such as the following first end condition example can be set as the predetermined end condition.

Here, in the first end condition example, even when the transmission power is changed within the range of the change width determined in advance in a certain cell, the communication characteristics after the change are not improved at all. It is determined that a certain cell satisfies the termination condition. In this example, since the index of 5% throughput is used as the communication characteristic, if the 5% throughput after the change is not improved at all with respect to the 5% throughput before the change, the termination condition is set for this certain cell. It is judged that For this certain cell, the transmission power is finally determined to a value provisionally determined before the termination condition is satisfied, and this certain cell is excluded from future search targets. The search is continued in a cell other than the certain cell excluded from the search target in a state where the transmission power of the excluded certain cell is fixed at the determined transmission power. And finally, even if the transmission power is changed within a predetermined range of change for all the cells, if no improvement can be obtained for the indicator of 5% throughput, the end condition for all the cells It is judged that Then, the transmission power is finally determined to a value provisionally determined before the termination condition is satisfied, and the search is terminated.

When the above termination condition is applied to this example, the communication throughput when the transmission power of the pico cell 32 is changed after the transmission power of the pico cell 33 is provisionally determined to 34 dBm is predicted. That is, since the transmission power of the pico cell 32 is provisionally determined up to 35 dBm, the communication throughput when the pico cell 32 transmission power is reduced to 34 dBm is predicted. As a result, 35/34: 3.8 Mbps and 34/34: 3.7 dBm are obtained, so even if 1 dBm, which is within the predetermined range of change, is lowered, an improvement is obtained for the 5% throughput index. Disappear. Therefore, it can be determined that the termination condition is satisfied for the pico cell 32, and the transmission power is determined to 35 dBm temporarily determined before the termination condition is satisfied for the pico cell 32. Then, the pico cell 32 is excluded from the target of the subsequent search.

Subsequently, if the transmission power of the pico cell 32 is determined to 35 dBm and then the search for the pico cell 33 is continued, the transmission power of the pico cell 33 is provisionally determined to 34 dBm, and therefore the pico cell 33 transmission power is reduced to 33 dBm. Predict communication throughput. As a result, 35/34: 3.8 Mbps and 35/33: 3.6 dBm are obtained, so even if the dBm is reduced within the predetermined range of change, an improvement on the 5% throughput index is obtained. It becomes impossible. Therefore, it can be determined that the termination condition is also satisfied for the pico cell 33, and the transmission power is determined to 34 dBm temporarily determined for the pico cell 33 before the termination condition is satisfied.

Note that a case is considered in which an improvement of the 5% throughput index is obtained if the picocell 33 transmission power is reduced to 33 dBm. In this case, since the pico cell 32 has already been excluded from the search target, the search is performed again for the pico cell 33. That is, it is determined whether or not an improvement of the 5% throughput index can be obtained when the transmission power of the pico cell 33 is reduced to 32 dBm. The search is continued until the picocell 33 satisfies the end condition.

Further, in the above description, even if the transmission power is changed within the range of the change width determined in advance in a certain cell, the communication characteristics after the change are not improved at all. Judged that the termination condition was satisfied. By modifying this, it may be determined that the end condition is satisfied when the communication characteristic after the change is no longer improved by a predetermined value or more compared to the communication characteristic before the change. In this example, if the 5% throughput index does not improve by, for example, 0.2 Mbps or more even if the dBm is reduced within the predetermined change range, it is determined that the termination condition is satisfied. You may do it. For example, if the 5% throughput before the change is 3.5 mMbps, if the 5% throughput after the change is 3.7 mMbps, the end condition is not satisfied because the improvement is 0.2 Mbps or more. On the other hand, if the 5% throughput after the change is 3.6 mM bps, the end condition is satisfied because it has not improved by 0.2 Mbps or more.

As another modification, it may be determined that the termination condition is satisfied when the communication characteristic after the change does not improve more than a predetermined ratio compared to the communication characteristic before the change. That is, a predetermined improvement rate may be set, and when the improvement does not improve more than this improvement rate, it may be determined that the end condition is satisfied. In this example, if the improvement rate of the 5% throughput index does not increase by 5% or more even if the dBm is reduced within the predetermined range of change, it is determined that the termination condition is satisfied. You may make it do. For example, if the 5% throughput before the change is 3.5 mMbps, the improvement rate is 5.7% if the 5% throughput after the change is 3.7 mMbps, so the termination condition is not satisfied. On the other hand, if the 5% throughput after the change is 3.6 mM bps, the improvement rate is 2.8%, which satisfies the termination condition.

In addition to the first end condition example described above, many end condition examples can be considered as the end condition. For example, a second end condition example may be considered in which it is determined that the end condition is satisfied for all cells when improvement in the index of 5% throughput is not obtained for at least one cell with respect to transmission power change. It is done. In this example, at the time when improvement in the index of 5% throughput cannot be obtained for at least one cell with respect to the transmission power change, the main transmission power before the termination condition is determined for all the cells, The search for the cell is terminated.

As another example of the end condition, when the improvement of the index of 5% throughput cannot be obtained with respect to the change of the transmission power of a certain cell, the transmission power of the certain cell is changed to the transmission power before the change. Continue the search in a fixed state. Then, if an improvement in the index of 5% throughput can be obtained in at least one cell other than the certain cell, the above-mentioned certain amount is based on the transmission power condition in which the improvement is obtained in the at least one cell. The search is continued in all the cells including the cell, and it is determined that the termination condition is satisfied when no improvement is finally obtained for all the cells. Finally, a method of finally determining the transmission power immediately before the end condition in all cells and ending the search is given as a third example of the end condition.

Furthermore, regardless of whether or not improvement about the 5% throughput index can no longer be obtained, the search continues to the lower limit value of the transmission power of all picocells, and among them, the combination with the highest 5% throughput index A fourth end condition example in which transmission power is determined can also be exemplified. This is repeated while switching the cells cyclically.

In the third embodiment, the case where the number of cells in the cooperation group is 2 has been described. However, the wireless parameter can be similarly determined when the number of cells is 3 or more.

For example, when the number of cells included in the cooperation group is 3, first, the priority is determined from 1 to 3, and then the transmission power of the cell with the priority 2 and the transmission power of the cell with the priority 3 Are fixed at the current values, and the transmission power of the cell having the priority of 1 is provisionally determined so that the communication characteristics are best within a predetermined range. Then, the transmission power of the cell with priority 1 is fixed to the value after provisional determination, the transmission power of the cell with priority 3 is fixed to the current value, and the transmission power of the cell with priority 2 is set to a predetermined value. Temporary determination is made so that the communication characteristics become the best within the range. Next, with the transmission power of the cell with priority 1 and the transmission power of the cell with priority 2 fixed to the values after provisional determination, the transmission power of the cell with priority 3 is within a predetermined range. The provisional determination is made so that the communication characteristics are the best.

The above operation is generally repeated several times. The repetition end condition is as described above. Moreover, although the said predetermined range is usually made narrower than the predetermined range of Example 2, it does not necessarily need to do so.

This is the same even when the number of cells included in the cooperation group becomes 4 or more.

Further, although the radio parameter to be controlled is transmission power, other radio parameters such as an antenna tilt angle, an antenna azimuth angle, and a handover parameter may be used. Furthermore, although one type of wireless parameter called transmission power is changed as the wireless parameter to be changed, the wireless parameter to be changed may be a combination of two or more types. Further, although the throughput is predicted as the prediction of the communication characteristics, other communication characteristics such as the traffic load and the signal-to-noise interference ratio such as SINR may be predicted. Furthermore, although the lower 5% throughput was examined this time, 5% is merely an example, and other values may be used. For example, the lower 3% may be used, or the average value or median value of all UEs 40 connected to the affected cell may be used. Further, although the change width to be changed at a time is 1 dBm, other change widths can be similarly applied.

Also, in the above example, on the premise that an improvement effect can be expected when the transmission power is lowered, an improvement in the index of throughput when the transmission power is lowered by 1 dBm is observed. However, if there is a possibility of an improvement effect when the transmission power is increased, an improvement effect when the transmission power is increased by 1 dBm in addition to the improvement effect regarding the throughput when the transmission power is reduced by 1 dBm. See also. In such a case, the transmission power is set in a direction in which improvement in the index of 5% throughput is obtained by comparing the throughput in the three cases of the case where the transmission power is not changed, the case where the transmission power is lowered by 1 dBm, and the case where the transmission power is increased by 1 dBm. change.

In the third embodiment, a change width to be changed at a time is determined in advance, and transmission power is determined while gradually changing radio parameters of a plurality of cells. Such a determination method is particularly effective when the difference between the upper limit value and the lower limit value of the radio parameter is large.

In the fourth embodiment, as in the second and third embodiments, the number of combinations for predicting the communication characteristics is limited by sequentially predicting the radio parameters one cell at a time for a plurality of cells in the cooperation group. . However, compared to the second and third embodiments, the fourth embodiment considers the order of cells for determining radio parameters from a plurality of viewpoints.

In the second and third embodiments, when determining the radio parameters of the cells in the cooperation group, for example, the cell for which the radio parameters are determined first is determined based on the traffic load of the cell. That is, one order is determined, and communication characteristics are predicted based on only this one order.

However, the fourth embodiment is different in that communication characteristics are predicted in a plurality of determination orders. In the fourth embodiment, based on a plurality of prediction results based on the plurality of determination orders, a wireless parameter that provides the greatest improvement in communication characteristics is determined.

In the fourth embodiment, the description will be made using the cell arrangement example shown in FIG. 5 as in the first to third embodiments. That is, as in the first embodiment, there is one macro cell (31) and two pico cells (pico cell 32 and pico cell 33), and the cells included in the cooperation group are only two pico cells (pico cell 32 and pico cell 33). Take a case as an example.

The same as in the first to third embodiments, in that the wireless parameter to be changed is transmission power, the predicted communication characteristic is user throughput, and the transmission power can be changed in increments of 1 dBm from 36 to 30 dBm in each picocell. To do.

Next, a communication characteristic prediction method according to the fourth embodiment will be described with reference to FIG.

In the fourth embodiment, the transmission power is determined in the order of the pico cell 32 → the pico cell 33 and the transmission power is determined in the order of the pico cell 33 → the pico cell 32, respectively, as in the second embodiment. A process of determining the transmission power of a cell at a time is performed. That is, in the fourth embodiment, communication characteristics are predicted in a plurality of determination orders, and transmission power is determined based on the communication characteristics. A plurality of transmission powers respectively corresponding to a plurality of determination orders are obtained. The plurality of predicted communication characteristics respectively corresponding to the obtained plurality of transmission powers are compared, and the transmission power corresponding to the communication characteristic that is superior is selected.

In this example, in the case of the order of the pico cell 32 → the pico cell 33, first, the transmission power of the pico cell 33 is fixed at 36 dBm, while the transmission power of the pico cell 32 is kept at 36 dBm. In each case where the change is made in increments of 1 dBm up to 30 dBm, 5% throughput in all UEs 40 connected to the affected cell is predicted. As a result, 35/36: 3.5 Mbps is obtained. After that, the transmission power of the pico cell 32 is fixed at 35 dBm, while the transmission power of the pico cell 33 is kept at 36 dBm, and the case where the transmission power of the pico cell 33 is changed to 30 dBm in 1 dBm increments is connected to the affected cell. Predict 5% throughput for all UEs 40 that do. As a result, 35/30: 4.2 Mbps is obtained as the maximum predicted throughput.

On the other hand, in the order of the pico cell 33 → the pico cell 32, the transmission power of the pico cell 32 is fixed at 36 dBm, while the transmission power of the pico cell 33 is kept at 36 dBm, and the transmission power of the pico cell 33 is increased by 1 dBm to 30 dBm. In each changed case, 5% throughput is predicted for all UEs 40 connected to both affected cells. As a result, 36/35: 3.8 Mbps is obtained. After that, the transmission power of the pico cell 33 is fixed at 35 dBm, while the transmission power of the pico cell 32 is kept at 36 dBm, and the case where the transmission power of the pico cell 32 is changed to 30 dBm in 1 dBm increments is connected to the affected cell. Predict 5% throughput for all UEs 40 that do. As a result, 35/35: 3.9 Mbps is obtained as the maximum predicted throughput.

Therefore, it is clear from the comparison between 35/30: 4.2 Mbps when changing in the order of picocell 32 → picocell 33 and 35/35: 3.9 Mbps when changing in order of picocell 33 → picocell 32. When the change is made in the order of the pico cell 32 → the pico cell 33, the improvement of the index of 5% throughput is larger than when the change is made in the order of the pico cell 33 → the pico cell 32. Therefore, the transmission power of the pico cell 32 and the pico cell 33 is determined to be 35/30 (pico cell 32: 35 dBm, pico cell 33:30 dBm).

In the fourth embodiment, the case where the number of cells in the cooperation group is 2 has been described. However, the wireless parameter can be similarly determined when the number of cells is 3 or more.

For example, if the cooperation group includes three cells, a first pico cell, a second pico cell, and a third pico cell, the first pico cell → the second pico cell → the third pico cell The predicted value of the communication characteristics when changed in order, the predicted value of the communication characteristics when changed in the second order of the first picocell → the third picocell → the second picocell, and the second picocell → the second Predicted value of communication characteristics when changed in the third order of 1 picocell → third picocell, and communication when changed in the fourth order of second picocell → third picocell → first picocell The predicted value of the characteristics, the predicted value of the communication characteristics when the third picocell → the first picocell → the second picocell is changed in the fifth order, and the third picocell → the second picocell → the first In the sixth order called Picocell Further the comparison six predicted value and the predicted value of the communication characteristic of the case, to determine and select the ones improvement in most communication characteristics is large.

Further, although the radio parameter to be controlled is transmission power, other radio parameters such as an antenna tilt angle, an antenna azimuth angle, and a handover parameter may be used. Furthermore, although one type of wireless parameter called transmission power is changed as the wireless parameter to be changed, the wireless parameter to be changed may be a combination of two or more types. Further, although the throughput is predicted as the prediction of the communication characteristics, other communication characteristics such as the traffic load and the signal-to-noise interference ratio such as SINR may be predicted. Furthermore, although the lower 5% throughput was examined this time, 5% is merely an example, and other values may be used. For example, the lower 3% may be used, or the average value or median value of all UEs 40 connected to the affected cell may be used.

In addition, in this explanation, the fourth embodiment is realized as a modification of the second embodiment (method for determining the radio parameters of each cell at a time), but the third embodiment (the radio parameters of a plurality of cells are changed little by little). However, the fourth embodiment may be realized as a modification of the method of determining the wireless parameter. Further, if it is realized as a modification of the third embodiment, the change width to be changed at a time may be set to an arbitrary value. Moreover, Example 2 and Example 3 may be mixed, and the improvement about the parameter | index of 5% throughput obtained by these may be compared.

In Example 4, since the order of cells for determining radio parameters can be considered from a plurality of viewpoints, the amount of calculation is larger than in Examples 2 and 3, but the effect of changing radio parameters can be increased. In particular, the effect can be increased in an environment where there is a great influence, such as when cells in a cooperation group are close to each other.

As described above, in the first embodiment, there are various wireless parameter changing methods having different characteristics improvement effects and different calculation amounts. Therefore, it is possible to select an optimal method according to the situation.

Further, in the first embodiment, after obtaining the radio parameters of a plurality of cells based on the prediction of the communication characteristics, the radio parameters of the plurality of cells are collectively controlled. As a result, the time required for control of the entire wireless communication system can be shortened.

Example 1 to Example 4 described above correspond to the first embodiment. Next, Example 5 which is an example corresponding to the second embodiment will be described.

In Examples 1 to 4 corresponding to Embodiment 1, the radio parameters of a plurality of cells are collectively controlled at one control timing. On the other hand, in Example 5 corresponding to Embodiment 2, only one cell in the cooperation group h is changed at a time at one control timing. Then, after actually changing the radio parameter of only one cell, the radio quality information and the communication quality information are acquired, and then the process of actually changing the radio parameter of one cell at the next control timing is repeated.

In the fifth embodiment, as in the first to fourth embodiments, description will be made using the cell arrangement example shown in FIG. That is, as in the first embodiment, there is one macro cell (31) and two pico cells (pico cell 32 and pico cell 33), and only two pico cells (pico cell 32 and pico cell 33) are included in the cooperation group. Take the case as an example.

In addition, the wireless power to be changed is transmission power, the predicted communication characteristic is user throughput, and the transmission power can be changed in increments of 1 dBm from 36 to 30 dBm in each picocell as in the first to fourth embodiments. To do.

Next, a communication characteristic prediction method according to the fifth embodiment will be described with reference to FIG. In the fifth embodiment, a method in which a cell whose radio parameter has been changed at a previous control timing or a cell that has been decided not to be changed is excluded from candidates for radio parameter change.

That is, the transmission power of two pico cells is changed one cell at a time. Further, as the completion condition, it is used to complete the change of radio parameters of all cells in the control group. That is, in this example, since two pico cells are targeted, the radio parameter of one of the pico cells is changed at the first control timing. Then, at the second control timing, the pico cell whose radio parameter has been changed at the first control timing is excluded from the candidates, and the radio parameter of the other pico cell that has not been changed is changed. Then, the change of the radio parameters of all cells in the control group is completed at the second control timing, and the completion condition is satisfied, so that the next time, the process is performed again as the first control timing. Become.

First, 5% throughput is predicted for all UEs 40 connected to the affected cell corresponding to each case where the transmission power of the

pico cells

32 and 33 is changed within a range of 36 to 30 dBm with a change width of 1 dBm. In the fifth embodiment, since it is assumed that the cells are controlled one by one, it is assumed that there is no change in the transmission power except for the cell in which the transmission power is assumed to be changed. First, the control target is a cell 33. Therefore, the transmission power of the cell 32 is fixed at 36 dBm. In this case, when the pico cell 33 is set to 35 dBm, the 5% throughput is maximum at 3.7 Mbps. Therefore, at the first control timing, the transmission power of the pico cell 33 is changed to 35 dBm.

Next, it is determined whether or not the completion condition is satisfied. In this case, since the transmission power of the pico cell 32 is not changed, radio quality measurement, communication quality measurement, and report to the radio parameter control apparatus 10 are performed for radio parameter control at the next control timing. Here, the UE 40 connected to the pico cell 32 and the pico cell 33 performs radio quality measurement, and the pico cell 32 and the pico cell 33 perform communication quality measurement.

Next, the radio parameters of the pico cell 32 are controlled using the measured radio quality measurement and communication quality measurement. Similar to the above, 5% throughput in all UEs 40 connected to the affected cell is predicted. At this time, the radio quality information and communication quality information used for 5% throughput prediction are information after being measured and updated under the transmission power changed at the initial control timing as described above. That is, the wireless quality information and the communication quality information when the transmission power of the cell 32 is 36 dBm and the transmission power of the cell 33 is 35 dBm are used.

In this example, since the transmission power of the pico cell 33 is 35 dBm at the second control timing, a 5% throughput is predicted based on this. At this time, the transmission power of the pico cell 32 is changed to 35 dBm because the transmission power of the pico cell 32 is 3.8 Mbps, which is a maximum value of 5% throughput corresponding to 35 dBm. Therefore, in the fifth embodiment, the transmission power of the pico cell 32 is changed from 36 dBm to 35 dBm, and the transmission power of the pico cell 33 is changed from 36 dBm to 35 dBm.

In the fifth embodiment, the case where the number of cells in the cooperation group is 2 has been described as an example. However, the wireless parameter can be similarly determined even when the number of cells is 3 or more.

Further, although the wireless parameter to be controlled is transmission power, other wireless parameters such as an antenna tilt angle, an antenna azimuth angle, and a handover parameter may be used. Furthermore, although one type of wireless parameter called transmission power is changed as the wireless parameter to be changed, the wireless parameter to be changed may be a combination of two or more types. Further, although the throughput is predicted as the prediction of the communication characteristics, other communication characteristics such as the traffic load and the signal-to-noise interference ratio such as SINR may be predicted. Furthermore, although the lower 5% throughput was examined this time, 5% is merely an example, and other values may be used. For example, the lower 3% may be used, or the average value or median value of all UEs 40 connected to the affected cell may be used. In the above, for all the cells in the cooperation group, the cell to be controlled first is determined based on the prediction of the communication characteristics. For example, the cell with the highest traffic load, the cell with the high abnormal disconnection rate of the call, A cell having a high effective number of scheduling users may be selected.

In the second embodiment, the form in which the cooperation group determined in step S103 is used over a plurality of control timings is shown, but this is not intended to limit the operation of the present embodiment.

For example, after the parameter of one cell in the cooperation group is completed, the cooperation group may be set again based on the changed communication quality information. Specifically, after the parameters of one cell in the cooperation group are finished, based on the changed communication quality information, the cell to be controlled is updated (equivalent to returning to step S100 in FIG. 3), The cooperation group may be updated after the setting of the affected cell of each cell is updated based on the radio quality information of the UE 40 (corresponding to returning to step S101 in FIG. 3).

In the second embodiment, the overall time required for control is longer than that in the first embodiment, but control based on the measurement result after changing the radio parameter is possible, and thus more accurate radio parameter control is possible. Has the advantageous effect of becoming

In each of the above-described embodiments, the case where only the radio parameter of the pico cell is changed has been described, but the present invention can be similarly applied to the case where the radio parameter of the macro cell is changed.

In the above embodiments, specific numerical values are exemplified and described. However, these are merely examples, and these specific numerical values are not intended to limit the application range of the present embodiment.

Note that the present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit of the present invention.

Also, the radio parameter control device and the radio parameter control system described above can be realized by hardware, software, or a combination thereof. Also, the radio parameter control method performed by the radio parameter control device and the radio parameter control system described above can be realized by hardware, software, or a combination thereof. Here, “realized by software” means realized by a computer reading and executing a program.

The program can be stored using various types of non-transitory computer readable media and supplied to a computer. Non-transitory computer readable media include various types of tangible storage media. Examples of non-transitory computer readable media include magnetic recording media (eg, flexible disk, magnetic tape, hard disk drive), magneto-optical recording media (eg, magneto-optical disc), CD-ROM (Read Only Memory), CD- R, CD-R / W, semiconductor memory (for example, mask ROM, PROM (Programmable ROM), EPROM (Erasable ROM), flash ROM, RAM (random access memory). The computer may be supplied by a computer readable medium (transitory 一時 computer コンピュータ readable medium) Examples of temporary computer readable media include electrical signals, optical signals, and electromagnetic waves. And the program can be supplied to the computer via a wired communication path such as an optical fiber or a wireless communication path. wear.

Some or all of the above embodiments can be described as in the following supplementary notes, but are not limited thereto.

(Supplementary note 1) A radio parameter control apparatus for controlling radio parameters for a cell group,
For each target cell included in one or more control target cells in the cell group, the radio parameters of the target cell are considered while taking into account the influence of the control on the radio parameter values of other cells in the cell group. Predicting means for predicting a change in communication characteristics in the cell group due to the change of
Control means for controlling radio parameter values of one or more of the control target cells in the cell group based on the prediction by the prediction means;
A wireless parameter control device comprising:

(Appendix 2)
The wireless parameter control device according to attachment 1, wherein
The prediction means performs the prediction for a plurality of the cells of interest,
The said control means controls the value of the radio | wireless parameter of these some attention cell based on the said prediction about the said some attention cell by the said prediction means, The radio | wireless parameter control apparatus characterized by the above-mentioned.

(Appendix 3)
The radio parameter control device according to

appendix

1 or 2,
The prediction means predicts a change in communication characteristics in the cell group for all combinations of predetermined ranges of radio parameter value change candidates for the plurality of cells of interest,
The control means determines a wireless parameter value change candidate that optimizes the communication characteristics as a changed wireless parameter value.

(Appendix 4)
The wireless parameter control device according to attachment 1, wherein
The predicting unit focuses on the plurality of cells of interest one by one, predicts a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused on sequentially,
The control means determines the value of the radio parameter of the target cell focused on in order based on the prediction,
When the prediction means predicts a change in communication characteristics due to a change in radio parameters of a target cell of interest, the prediction means is determined for a cell whose radio parameters have already been determined by the control means. A radio parameter control apparatus using a radio parameter value.

(Appendix 5)
The wireless parameter control device according to attachment 1, wherein
The predicting unit focuses on the plurality of cells of interest one by one, predicts a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused on sequentially,
The control means tentatively determines the value of the radio parameter of the cell of interest focused on sequentially based on the prediction,
When the prediction means predicts a change in communication characteristics due to a change in the radio parameter of the target cell of interest, the prediction means is determined for a cell whose radio parameter has already been provisionally determined by the control means. Using the value of the wireless parameter
A radio parameter control apparatus that repeats the prediction and the tentative determination based on the prediction until a predetermined condition is satisfied, and determines the radio parameter that is tentatively determined at the end of the repetition as a radio parameter after change .

(Appendix 6)
The radio parameter control device according to

appendix

1 or 2,
The prediction means focuses on the plurality of cells of interest by a plurality of methods, predicts changes in a plurality of communication characteristics respectively corresponding to the plurality of methods,
The radio parameter control apparatus, wherein the control unit controls radio parameter values of the plurality of cells of interest based on changes in a plurality of communication characteristics respectively corresponding to the plurality of methods by the prediction unit.

(Supplementary note 7) The wireless parameter control device according to any one of supplementary notes 1 to 6,
A radio parameter control apparatus, further comprising means for simultaneously setting radio parameters determined by control in corresponding radio base stations.

(Appendix 8)
The wireless parameter control device according to attachment 1, wherein
The prediction means performs the prediction for one of the cells of interest,
The control means tentatively determines a radio parameter value of the one target cell based on the prediction by the prediction means,
The radio parameter control device
Setting means for setting a radio parameter whose value is provisionally determined by the control means to a corresponding radio base station;
Measuring means for measuring radio quality information and / or communication quality information after radio parameters are set by the setting means;
Further comprising
The prediction means, the control means, the setting means, and the measurement means are repeatedly operated, and in each repetition, the prediction means performs radio quality information and / or communication quality information measured by the measurement means in the previous repetition. A radio parameter control apparatus that predicts a change in the communication characteristics using a wireless communication device.

(Supplementary note 9) The wireless parameter control device according to any one of supplementary notes 1 to 8,
The radio parameter control apparatus characterized in that the communication characteristics include at least one of traffic load, resource utilization, effective number of scheduling users, user throughput, cell throughput, and reception quality (RSRP, RSRQ, SINR).

(Supplementary Note 10) A radio parameter control method for controlling radio parameters for a cell group,
For each target cell included in one or more control target cells in the cell group, the radio parameters of the target cell are considered while taking into account the influence of the control on the radio parameter values of other cells in the cell group. A prediction step for predicting a change in communication characteristics in the cell group due to a change in
A control step of controlling a value of a radio parameter of one or more of the control target cells in the cell group based on the prediction by the prediction step;
A wireless parameter control method comprising:

(Additional remark 11) It is a radio | wireless parameter control method of Additional remark 10, Comprising:
In the prediction step, the prediction for a plurality of the cells of interest is performed,
In the control step, a radio parameter control method for controlling radio parameter values of the plurality of cells of interest based on the prediction of the plurality of cells of interest in the prediction step.

(Supplementary note 12) The radio parameter control method according to

supplementary note

10 or 11,
In the prediction step, for all combinations of a predetermined range of radio parameter value change candidates for the plurality of cells of interest, a change in communication characteristics in the cell group is predicted,
In the control step, a radio parameter value change candidate that optimizes the communication characteristics is determined as a radio parameter value after the change.

(Supplementary note 13) The wireless parameter control method according to supplementary note 10, wherein
In the prediction step, pay attention to the plurality of cells of interest one by one in order, and predict a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused one after another,
In the control step, the value of the radio parameter of the cell of interest focused sequentially is determined based on the prediction,
In the predicting step, when predicting a change in communication characteristics due to a change in radio parameters of a target cell of interest, the cell in which the radio parameters have already been determined in the control step is determined. A radio parameter control method using a radio parameter value.

(Supplementary note 14) The radio parameter control method according to supplementary note 10, wherein
In the prediction step, pay attention to the plurality of cells of interest one by one in order, and predict a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused one after another,
In the control step, the radio parameter value of the cell of interest focused on in order is provisionally determined based on the prediction,
In the prediction step, when predicting a change in communication characteristics due to a change in the radio parameter of the cell of interest that is currently focused on, the cell in which the radio parameter has already been provisionally determined in the control step is determined. Using the value of the wireless parameter
A radio parameter control method characterized by repeating the prediction and the tentative determination based on the prediction until a predetermined condition is satisfied, and determining a radio parameter temporarily determined at the end of the repetition as a radio parameter after change .

(Supplementary note 15) The radio parameter control method according to

supplementary note

10 or 11,
In the predicting step, a plurality of methods are focused on the plurality of cells of interest, and a plurality of communication characteristics corresponding to the plurality of methods are predicted,
The radio parameter control method characterized in that, in the control step, radio parameter values of the plurality of cells of interest are controlled based on changes in a plurality of communication characteristics respectively corresponding to the plurality of methods in the prediction step.

(Supplementary note 16) The wireless parameter control method according to any one of supplementary notes 10 to 15,
A radio parameter control method further comprising the step of simultaneously setting radio parameters determined by control in corresponding radio base stations.

(Supplementary note 17) The radio parameter control method according to supplementary note 10, wherein
In the prediction step, the prediction for one of the cells of interest is performed,
In the control step, based on the prediction in the prediction step, the wireless parameter value of the one target cell is provisionally determined,
The radio parameter control method is:
A setting step of setting the radio parameter whose value is provisionally determined in the control step in a corresponding radio base station;
A measurement step of measuring radio quality information and / or communication quality information after radio parameters are set by the setting step;
Further comprising
The prediction step, the control step, the setting step, and the measurement step are repeated. In each iteration, the prediction step includes the radio quality information and / or communication quality information measured by the measurement step in the previous iteration. A radio parameter control method characterized in that a change in the communication characteristics is predicted using the method.

(Supplementary note 18) The wireless parameter control method according to any one of supplementary notes 10 to 17,
The radio parameter control method characterized in that the communication characteristics include at least one of traffic load, resource utilization, effective number of scheduling users, user throughput, cell throughput, and reception quality (RSRP, RSRQ, SINR).

(Supplementary note 19) A radio parameter control program for causing a computer to function as a radio parameter control device for controlling radio parameters for a cell group,
The computer,
For each target cell included in one or more control target cells in the cell group, the radio parameters of the target cell are considered while taking into account the influence of the control on the radio parameter values of other cells in the cell group. Predicting means for predicting a change in communication characteristics in the cell group due to the change of
Control means for controlling radio parameter values of one or more of the control target cells in the cell group based on the prediction by the prediction means;
A wireless parameter control program that functions as a wireless parameter control device.

(Supplementary note 20) The wireless parameter control program according to supplementary note 19,
The prediction means performs the prediction for a plurality of the cells of interest,
The control means further causes the computer to function as a radio parameter control apparatus that controls radio parameter values of the plurality of cells of interest based on the prediction of the plurality of cells of interest by the prediction unit. Wireless parameter control program.

(Supplementary note 21) The wireless parameter control program according to supplementary note 19 or 20,
The prediction means predicts a change in communication characteristics in the cell group for all combinations of predetermined ranges of radio parameter value change candidates for the plurality of cells of interest,
The control means further causes the computer to function as a wireless parameter control device that determines a wireless parameter value change candidate that optimizes the communication characteristics as a changed wireless parameter value. .

(Supplementary note 22) The wireless parameter control program according to supplementary note 19,
The predicting unit focuses on the plurality of cells of interest one by one, predicts a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused on sequentially,
The control means determines the value of the radio parameter of the target cell focused on in order based on the prediction,
When the prediction means predicts a change in communication characteristics due to a change in radio parameters of a target cell of interest, the prediction means is determined for a cell whose radio parameters have already been determined by the control means. A wireless parameter control program that further causes the computer to function as a wireless parameter control device that uses wireless parameter values.

(Supplementary note 23) The wireless parameter control program according to supplementary note 19,
The predicting unit focuses on the plurality of cells of interest one by one, predicts a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused on sequentially,
The control means tentatively determines the value of the radio parameter of the cell of interest focused on sequentially based on the prediction,
When the prediction means predicts a change in communication characteristics due to a change in the radio parameter of the target cell of interest, the prediction means is determined for a cell whose radio parameter has already been provisionally determined by the control means. Using the value of the wireless parameter
The computer is further used as a wireless parameter control device that repeats the prediction and the tentative determination based on the prediction until a predetermined condition is satisfied, and determines the wireless parameter temporarily determined at the end of the repetition as a wireless parameter after change. A wireless parameter control program which is made to function.

(Supplementary note 24) The radio parameter control program according to supplementary note 19 or 20,
The prediction means focuses on the plurality of cells of interest by a plurality of methods, predicts changes in a plurality of communication characteristics respectively corresponding to the plurality of methods,
The control means further functions the computer as a radio parameter control apparatus that controls radio parameter values of the plurality of cells of interest based on changes in a plurality of communication characteristics respectively corresponding to the plurality of methods by the prediction means. A wireless parameter control program characterized in that

(Supplementary note 25) The wireless parameter control program according to any one of supplementary notes 19 to 24,
A wireless parameter control program that further causes the computer to function as a wireless parameter control device further comprising means for simultaneously setting wireless parameters determined by control in corresponding wireless base stations.

(Supplementary note 26) The wireless parameter control program according to supplementary note 19,
The prediction means performs the prediction for one of the cells of interest,
The control means tentatively determines a radio parameter value of the one target cell based on the prediction by the prediction means,
The wireless parameter control device includes:
Setting means for setting a radio parameter whose value is provisionally determined by the control means to a corresponding radio base station;
Measuring means for measuring radio quality information and / or communication quality information after radio parameters are set by the setting means;
Further comprising
The prediction means, the control means, the setting means, and the measurement means are repeatedly operated, and in each repetition, the prediction means performs radio quality information and / or communication quality information measured by the measurement means in the previous repetition. A wireless parameter control program that further causes the computer to function as a wireless parameter control device that predicts a change in the communication characteristics using a computer.

(Supplementary note 27) The wireless parameter control program according to any one of supplementary notes 19 to 26,
The communication characteristics include at least one of traffic load, resource utilization rate, effective number of scheduling users, user throughput, cell throughput, reception quality (RSRP, RSRQ, SINR), and further functions the computer as a radio parameter control device A wireless parameter control program characterized in that

(Supplementary note 28) A radio parameter control system comprising: a base station that performs radio communication with a terminal; and a radio parameter control device connected to the base station,
The base station
Reporting means for reporting to the base station quality related to wireless communication measured based on communication with the terminal;
Changing means for changing a radio parameter for a cell under the base station according to an instruction of a change value of the radio parameter control device,
The wireless parameter control device is the wireless parameter control device according to any one of appendices 1 to 9, wherein the prediction unit and the control unit are operated based on a report content by the reporting unit, and the control unit Instructing the base station to change the radio parameter based on the determined change value of the radio parameter;
A wireless parameter control system.

(Supplementary note 29) A radio parameter control method performed by a system including a base station that performs radio communication with a terminal and a radio parameter control device connected to the base station,
A reporting step in which the base station reports to the base station the quality related to wireless communication measured based on communication with the terminal;
The wireless parameter control device performs the wireless parameter control method according to any one of appendices 10 to 18, and performs the prediction step and the control step based on a report content of the reporting step, and the control Instructing the base station to change a radio parameter based on a change value of the radio parameter determined in the step;
The base station changes a radio parameter for a cell under the base station according to an instruction of a change value of the radio parameter control device; and
A wireless parameter control method comprising:

This application claims priority based on Japanese Patent Application No. 2012-284818 filed on December 27, 2012, the entire disclosure of which is incorporated herein.

The present invention can be applied to any wireless communication network conforming to the cellular system regardless of its use or the contents of parameters to be changed.

DESCRIPTION OF SYMBOLS 10 Radio parameter control apparatus 11 Quality information storage part 12 Influence cell determination part 13 Communication characteristic prediction part 14 Radio parameter determination part 20, 20-1, 20-2, 20-3, 1000 Base station 21 Communication part 22 Communication quality measurement part 23 Quality management unit 24 Radio

parameter adjustment unit

30, 31, 32, 33, 1001, 2001, 2002, 3001, 3002 Cell 40 UE
41 Communication unit 42 Wireless quality measurement unit 2000, 3000 Small base station

Claims

A radio parameter control device for controlling radio parameters for a cell group,
For each target cell included in one or more control target cells in the cell group, the radio parameters of the target cell are considered while taking into account the influence of the control on the radio parameter values of other cells in the cell group. Predicting means for predicting a change in communication characteristics in the cell group due to the change of
Control means for controlling radio parameter values of one or more of the control target cells in the cell group based on the prediction by the prediction means;
A wireless parameter control device comprising:
The radio parameter control device according to claim 1,
The prediction means performs the prediction for a plurality of the cells of interest,
The said control means controls the value of the radio | wireless parameter of these some attention cell based on the said prediction about the said some attention cell by the said prediction means, The radio | wireless parameter control apparatus characterized by the above-mentioned.
The radio parameter control device according to claim 1 or 2,
The prediction means predicts a change in communication characteristics in the cell group for all combinations of predetermined ranges of radio parameter value change candidates for the plurality of cells of interest,
The control means determines a wireless parameter value change candidate that optimizes the communication characteristics as a changed wireless parameter value.
The radio parameter control device according to claim 1,
The predicting unit focuses on the plurality of cells of interest one by one, predicts a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused on sequentially,
The control means determines the value of the radio parameter of the target cell focused on in order based on the prediction,
When the prediction means predicts a change in communication characteristics due to a change in radio parameters of a target cell of interest, the prediction means is determined for a cell whose radio parameters have already been determined by the control means. A radio parameter control apparatus using a radio parameter value.
The radio parameter control device according to claim 1,
The predicting unit focuses on the plurality of cells of interest one by one, predicts a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused on sequentially,
The control means tentatively determines the value of the radio parameter of the cell of interest focused on sequentially based on the prediction,
When the prediction means predicts a change in communication characteristics due to a change in the radio parameter of the target cell of interest, the prediction means is determined for a cell whose radio parameter has already been provisionally determined by the control means. Using the value of the wireless parameter
A radio parameter control apparatus that repeats the prediction and the tentative determination based on the prediction until a predetermined condition is satisfied, and determines the radio parameter that is tentatively determined at the end of the repetition as a radio parameter after change .
The radio parameter control device according to claim 1 or 2,
The prediction means focuses on the plurality of cells of interest by a plurality of methods, predicts changes in a plurality of communication characteristics respectively corresponding to the plurality of methods,
The radio parameter control apparatus, wherein the control unit controls radio parameter values of the plurality of cells of interest based on changes in a plurality of communication characteristics respectively corresponding to the plurality of methods by the prediction unit.
The wireless parameter control device according to any one of claims 1 to 6,
A radio parameter control apparatus, further comprising means for simultaneously setting radio parameters determined by control in corresponding radio base stations.
The radio parameter control device according to claim 1,
The prediction means performs the prediction for one of the cells of interest,
The control means tentatively determines a radio parameter value of the one target cell based on the prediction by the prediction means,
The radio parameter control device
Setting means for setting a radio parameter whose value is provisionally determined by the control means to a corresponding radio base station;
Measuring means for measuring radio quality information and / or communication quality information after radio parameters are set by the setting means;
Further comprising
The prediction means, the control means, the setting means, and the measurement means are repeatedly operated, and in each repetition, the prediction means performs radio quality information and / or communication quality information measured by the measurement means in the previous repetition. A radio parameter control apparatus that predicts a change in the communication characteristics using a wireless communication device.
The radio parameter control device according to any one of claims 1 to 8,
The radio parameter control apparatus characterized in that the communication characteristics include at least one of traffic load, resource utilization, effective number of scheduling users, user throughput, cell throughput, and reception quality (RSRP, RSRQ, SINR).
A radio parameter control method for controlling radio parameters for a cell group, comprising:
For each target cell included in one or more control target cells in the cell group, the radio parameters of the target cell are considered while taking into account the influence of the control on the radio parameter values of other cells in the cell group. A prediction step for predicting a change in communication characteristics in the cell group due to a change in
A control step of controlling a value of a radio parameter of one or more of the control target cells in the cell group based on the prediction by the prediction step;
A wireless parameter control method comprising:
The radio parameter control method according to claim 10, comprising:
In the prediction step, the prediction for a plurality of the cells of interest is performed,
In the control step, a radio parameter control method for controlling radio parameter values of the plurality of cells of interest based on the prediction of the plurality of cells of interest in the prediction step.
The radio parameter control method according to claim 10 or 11,
In the prediction step, for all combinations of a predetermined range of radio parameter value change candidates for the plurality of cells of interest, a change in communication characteristics in the cell group is predicted,
In the control step, a radio parameter value change candidate that optimizes the communication characteristics is determined as a radio parameter value after the change.
The radio parameter control method according to claim 10, comprising:
In the prediction step, pay attention to the plurality of cells of interest one by one in order, and predict a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused one after another,
In the control step, the value of the radio parameter of the cell of interest focused sequentially is determined based on the prediction,
In the predicting step, when predicting a change in communication characteristics due to a change in radio parameters of a target cell of interest, the cell in which the radio parameters have already been determined in the control step is determined. A radio parameter control method using a radio parameter value.
The radio parameter control method according to claim 10, comprising:
In the prediction step, pay attention to the plurality of cells of interest one by one in order, and predict a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused one after another,
In the control step, the radio parameter value of the cell of interest focused on in order is provisionally determined based on the prediction,
In the prediction step, when predicting a change in communication characteristics due to a change in the radio parameter of the cell of interest that is currently focused on, the cell in which the radio parameter has already been provisionally determined in the control step is determined. Using the value of the wireless parameter
A radio parameter control method characterized by repeating the prediction and the tentative determination based on the prediction until a predetermined condition is satisfied, and determining a radio parameter temporarily determined at the end of the repetition as a radio parameter after change .
The radio parameter control method according to claim 10 or 11,
In the prediction step, a plurality of methods are focused on the plurality of cells of interest, and a plurality of communication characteristic changes corresponding to the plurality of methods are predicted,
The radio parameter control method characterized in that, in the control step, radio parameter values of the plurality of cells of interest are controlled based on changes in a plurality of communication characteristics respectively corresponding to the plurality of methods in the prediction step.
The radio parameter control method according to any one of claims 10 to 15,
A radio parameter control method further comprising the step of simultaneously setting radio parameters determined by control in corresponding radio base stations.
The radio parameter control method according to claim 10, comprising:
In the prediction step, the prediction for one of the cells of interest is performed,
In the control step, based on the prediction in the prediction step, the wireless parameter value of the one target cell is provisionally determined,
The radio parameter control method is:
A setting step of setting the radio parameter whose value is provisionally determined in the control step in a corresponding radio base station;
A measurement step of measuring radio quality information and / or communication quality information after radio parameters are set by the setting step;
Further comprising
The prediction step, the control step, the setting step, and the measurement step are repeated. In each iteration, the prediction step includes the radio quality information and / or communication quality information measured by the measurement step in the previous iteration. A radio parameter control method characterized in that a change in the communication characteristics is predicted.
The radio parameter control method according to any one of claims 10 to 17,
The radio parameter control method characterized in that the communication characteristics include at least one of traffic load, resource utilization, effective number of scheduling users, user throughput, cell throughput, and reception quality (RSRP, RSRQ, SINR).
A radio parameter control program for causing a computer to function as a radio parameter control device for controlling radio parameters for a cell group,
The computer,
For each target cell included in one or more control target cells in the cell group, the radio parameters of the target cell are considered while taking into account the influence of the control on the radio parameter values of other cells in the cell group. Predicting means for predicting a change in communication characteristics in the cell group due to the change of
Control means for controlling radio parameter values of one or more of the control target cells in the cell group based on the prediction by the prediction means;
A wireless parameter control program that functions as a wireless parameter control device.
A radio parameter control program according to claim 19,
The prediction means performs the prediction for a plurality of the cells of interest,
The control means further causes the computer to function as a radio parameter control apparatus that controls radio parameter values of the plurality of cells of interest based on the prediction of the plurality of cells of interest by the prediction unit. Wireless parameter control program.
The radio parameter control program according to claim 19 or 20,
The prediction means predicts a change in communication characteristics in the cell group for all combinations of predetermined ranges of radio parameter value change candidates for the plurality of cells of interest,
The control means further causes the computer to function as a wireless parameter control device that determines a wireless parameter value change candidate that optimizes the communication characteristics as a changed wireless parameter value. .
A radio parameter control program according to claim 19,
The predicting unit focuses on the plurality of cells of interest one by one, predicts a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused on sequentially,
The control means determines the value of the radio parameter of the target cell focused on in order based on the prediction,
When the prediction means predicts a change in communication characteristics due to a change in radio parameters of a target cell of interest, the prediction means is determined for a cell whose radio parameters have already been determined by the control means. A wireless parameter control program that further causes the computer to function as a wireless parameter control device that uses wireless parameter values.
A radio parameter control program according to claim 19,
The predicting unit focuses on the plurality of cells of interest one by one, predicts a change in communication characteristics in the cell group due to a change in radio parameters of the cells of interest focused on sequentially,
The control means tentatively determines the value of the radio parameter of the cell of interest focused on sequentially based on the prediction,
When the prediction means predicts a change in communication characteristics due to a change in the radio parameter of the target cell of interest, the prediction means is determined for a cell whose radio parameter has already been provisionally determined by the control means. Using the value of the wireless parameter
The computer is further used as a wireless parameter control device that repeats the prediction and the tentative determination based on the prediction until a predetermined condition is satisfied, and determines the wireless parameter temporarily determined at the end of the repetition as a wireless parameter after change. A wireless parameter control program which is made to function.
The radio parameter control program according to claim 19 or 20,
The prediction means focuses on the plurality of cells of interest by a plurality of methods, predicts changes in a plurality of communication characteristics respectively corresponding to the plurality of methods,
The control means further functions the computer as a radio parameter control apparatus that controls radio parameter values of the plurality of cells of interest based on changes in a plurality of communication characteristics respectively corresponding to the plurality of methods by the prediction means. A wireless parameter control program characterized in that
A wireless parameter control program according to any one of claims 19 to 24,
A wireless parameter control program that further causes the computer to function as a wireless parameter control device further comprising means for simultaneously setting wireless parameters determined by control in corresponding wireless base stations.
A radio parameter control program according to claim 19,
The prediction means performs the prediction for one of the cells of interest,
The control means tentatively determines a radio parameter value of the one target cell based on the prediction by the prediction means,
The wireless parameter control device includes:
Setting means for setting a radio parameter whose value is provisionally determined by the control means to a corresponding radio base station;
Measuring means for measuring radio quality information and / or communication quality information after radio parameters are set by the setting means;
Further comprising
The prediction means, the control means, the setting means, and the measurement means are repeatedly operated, and in each repetition, the prediction means performs radio quality information and / or communication quality information measured by the measurement means in the previous repetition. A wireless parameter control program that further causes the computer to function as a wireless parameter control device that predicts a change in the communication characteristics using a computer.
A radio parameter control program according to any one of claims 19 to 26,
The communication characteristics include at least one of traffic load, resource utilization rate, effective number of scheduling users, user throughput, cell throughput, reception quality (RSRP, RSRQ, SINR), and further functions the computer as a radio parameter control device A wireless parameter control program characterized in that
A radio parameter control system comprising: a base station that performs radio communication with a terminal; and a radio parameter control device connected to the base station,
The base station
Reporting means for reporting to the base station quality related to wireless communication measured based on communication with the terminal;
Changing means for changing a radio parameter for a cell under the base station according to an instruction of a change value of the radio parameter control device,
The radio parameter control device according to any one of claims 1 to 9, wherein the radio parameter control device operates the prediction unit and the control unit based on a report content by the report unit, and performs the control. Instructing the base station to change a radio parameter based on a change value of the radio parameter determined by the means;
A wireless parameter control system.
A radio parameter control method performed by a system comprising: a base station that performs radio communication with a terminal; and a radio parameter control device connected to the base station,
A reporting step in which the base station reports to the base station the quality related to wireless communication measured based on communication with the terminal;
The wireless parameter control device is a device that performs the wireless parameter control method according to any one of claims 10 to 18, wherein the prediction step and the control step are performed based on a report content by the reporting step, Instructing the base station to change a radio parameter based on a change value of the radio parameter determined by the control step;
The base station changes a radio parameter for a cell under the base station according to an instruction of a change value of the radio parameter control device; and
A wireless parameter control method comprising: