JP2014072633A - Indoor base station, wireless communication system, and method for controlling wireless communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an indoor base station, etc. for a wireless communication system capable of avoiding communication interference between base stations more precisely, especially regarding the indoor base station.SOLUTION: When a transmission power value of an indoor base station is controlled on the basis of the presence situation of terminals distributed within a cell of the indoor base station, a process is executed to determine terminals distributed outside a building, and to exclude the same from the terminals which are taken into consideration when the transmission power value is controlled. In this way, an excessive increase in the transmission power of the indoor base station, causing interference to terminals belonging to adjacent base stations can be avoided, and a decline in the communication quality of terminals belonging to adjacent base stations because of that the transmission power of the adjacent base stations is reduced to avoid interference with the adjacent base stations can be avoided.

Description

  The present invention relates to communication interference between devices constituting a wireless communication system or the like, particularly between base stations.

In recent years, mobile phone penetration and market expansion, and is progressing diversification of services, 3GPP of (3 ^rd Generation Partnership Project) evolved toward the 4th generation mobile communication technology to achieve a high-speed large-capacity communication even in LTE (Long-Term Evolution) and LTE-Advanced are standardized as one of radio access technologies.

  On the other hand, it is predicted that the number of base stations to be installed will increase as the size of the cell advances. Wireless base stations are classified into outdoor base stations installed on outdoor steel towers, rooftops of buildings, and the like, and indoor base stations that mainly use buildings as communication areas. The outdoor base station has a cell radius of about 100 to 10 km depending on the installation environment. In an indoor base station for general homes called a femto base station, the cell radius is several tens of meters or less.

  As described above, since the cell size is different between the outdoor base station and the indoor base station, the cell configuration generally includes the indoor base station in the wireless cell of the outdoor base station. Moreover, since an indoor base station can be installed in an arbitrary place by a user, cell overlap occurs between indoor base stations. When the outdoor base station and the indoor base station use the same frequency, an interference problem occurs between the outdoor base station and the indoor base station and between the indoor base stations.

  In order to solve this problem, generally, in an indoor base station, there is a method of measuring the power value of signals received from an outdoor base station and other indoor base stations and adjusting the transmission power value of the indoor base station based on the measurement result. It is used.

  In the following Patent Document 1, the base station acquires the measurement result of the radio quality of the downlink signal transmitted from the base station around the terminal, measured at the terminal, and at the terminal position where the radio quality of the signal is below a predetermined reference A method for controlling the transmission power of a base station so that the radio quality of a signal exceeds a predetermined standard is disclosed.

  In the following Patent Document 2, the base station calculates the distance from the base station to the cell edge based on the location information of the terminal reported from the terminal and the received power value of the downlink signal transmitted from the base station. A technique is disclosed in which at least one of a plurality of parameters including transmission power for a terminal is controlled so that an error between a measurement cell coverage as a radius and a target cell coverage is reduced.

International Publication No. 2011-070733 Pamphlet International Publication No. 2011-114372 Pamphlet

  However, in the above method, when the penetration loss of the building in which the indoor base station is installed is large, when the terminal that belongs to the indoor base station and the wireless quality is lower than the predetermined standard exists outside the building, Since the transmission power of the indoor base station is greatly adjusted, the downlink transmission signal of the indoor base station causes a great deal of interference with terminals belonging to the indoor base station adjacent to the indoor base station. There was a problem.

  The present invention has been made in view of this problem, and an object thereof is to provide an indoor base station and the like for a wireless communication system that can avoid communication interference between base stations more accurately particularly with respect to indoor base stations.

  The present invention includes a plurality of base stations that can communicate with each other, including an outdoor base station and an indoor base station, and a plurality of terminals that can communicate with the base station in any of the base station cells of the plurality of base stations. A plurality of base stations and a plurality of terminals, which are indoor base stations for a wireless communication system in which communication is performed using a signal including its own identification number, measured from a terminal belonging to the indoor base station Radio quality is predetermined based on a communication state information collecting unit that collects the downlink received power value of each base station that has been received, the downlink received power value collected from the terminal, and the CINR value that is correlated with the downlink received power value A “cell edge terminal” that is less than or equal to the reference value of “the outdoor terminal” that exists outside the building where the indoor base station is installed, and among the cell edge terminals, the terminal that is also the outdoor terminal is Selue A base station discriminating number that interferes with a terminal that is regarded as a cell edge, a terminal type discriminating unit that transmits the discriminating number of the terminal to another base station, and a signal from the other base station An adjacent relationship determination unit that determines the adjacent relationship between the indoor base station and the outdoor base station from the determination number, and information on the cell edge terminal obtained from the indoor base station and the cell edge terminal from another base station A transmission power value determining unit that determines a transmission power value of the indoor base station based on the information and the adjacency relationship.

  According to the present invention, it is possible to provide an indoor base station or the like for a wireless communication system that can avoid communication interference between base stations more accurately particularly with respect to an indoor base station.

It is a figure which shows the structure of the radio | wireless communications system by Embodiment 1 of this invention. It is a block block diagram of each apparatus in the radio | wireless communications system of Embodiment 1 of this invention. It is an image figure of the process in the indoor base station of Embodiment 1 of this invention. It is a figure which shows an example of the data in the database of the indoor base station of Embodiment 1 of this invention. It is an operation | movement flowchart in the indoor base station in Embodiment 1 of this invention. It is a figure which shows the structure of the radio | wireless communications system containing the base station and control apparatus by Embodiment 2 and 3 of this invention. It is a block block diagram of each apparatus in the radio | wireless communications system of Embodiment 2 and 3 of this invention. It is an operation | movement flowchart in the indoor base station in Embodiment 2 of this invention. It is an operation | movement flowchart in the control apparatus in Embodiment 2 of this invention. It is a figure which shows an example of the data in the database of the indoor base station of Embodiment 3 of this invention. It is an operation | movement flowchart in the indoor base station in Embodiment 3 of this invention. It is an operation | movement flowchart in the control apparatus in Embodiment 3 of this invention.

  The present invention performs processing for excluding terminals existing outside the building from terminals considered when controlling the transmission power value of the indoor base station, so that the transmission power of the indoor base station is excessively increased and the adjacent indoor It avoids giving a great deal of interference to terminals belonging to a base station or the like.

  In addition, the present invention is basically applied to a mobile communication system in which the terminal is a mobile terminal. However, even if the terminal is a fixed terminal, for example, there is a relocation of the fixed terminal (including a wireless LAN terminal or the like). The present invention can also be applied.

  Hereinafter, an indoor base station and a wireless communication system including the indoor base station according to the present invention will be described with reference to the drawings. In each embodiment, the same or corresponding parts are denoted by the same reference numerals, and redundant description is omitted.

Embodiment 1 FIG.
1 is a diagram showing a configuration of a radio communication system according to Embodiment 1 of the present invention. In FIG. 1, signals transmitted from the indoor base station 01 are terminals 21 and 22, signals transmitted from the indoor base station 02 are terminals 22 and 23, and signals transmitted from the outdoor base station 11 are terminals 21 to 24. It can be received.

  In FIG. 1, terminals 21 and 22 belong to the indoor base station 01, terminal 23 belongs to the indoor base station 02, and terminal 24 belongs to the outdoor base station 11. The indoor base stations 01 and 02 and the terminals 21 and 22 exist indoors, and the outdoor base station 11 and the terminals 23 and 24 exist outdoors. C11, C01, and C02 indicate cells of the outdoor base station 11 and the indoor base stations 01 and 02, respectively.

All indoor and outdoor base stations can communicate with each other.
If all terminals can communicate with one of the base stations in the cell of the base station and can receive a downlink transmission signal from the base station, an RSRP (Reference Signal Received) that is a received power value of the downlink transmission signal is received. (Power: reference signal received power) value is measured, and the measured value and the identification number of the base station transmitting the signal are reported to the base station to which it belongs. Here, the identification number for identifying itself is included in the signal transmitted by each base station and terminal. If there are a plurality of signals that can be received, a plurality of RSRP values (downlink received power values) are measured, and the values and the identification numbers of the base stations are reported to the base station to which they belong.

  FIG. 2 shows a block configuration diagram of each device in the wireless communication system of the first embodiment. FIG. 3 shows an image diagram of processing in the indoor base station of the first embodiment.

In FIG. 2, the indoor base stations 01 and 02 include the following.
RSRP collection (part) function (or communication state information collection (part) function) 002 is communication state information measured at the terminal from a terminal belonging to the own base station using inter-terminal communication (part) function 001. Collect RSRP values for each base station.

Based on the RSRP value collected from the terminal, the terminal type determination (unit) function 003 determines that the radio quality is equal to or lower than a predetermined reference value due to interference of downlink signals from other than the belonging base station or noise power. Whether or not it is a “cell edge terminal (terminal at the cell edge of the base station)” and “outdoor terminal” that belongs to its own base station and exists outside the building where it is installed (Based on the downlink received power value collected from the terminal and the CINR value correlated with the downlink received power value, the radio quality is equal to or less than a predetermined reference value “cell edge terminal `` And the `` outdoor terminal '' existing outside the building where the indoor base station is installed), among the cell edge terminals belonging to the base station, a terminal that is also an outdoor terminal is not regarded as a cell edge terminal ( CINR value: Below Indicates the ratio between the received power value and (interference power value + noise power value)).
Then, by using the inter-base station communication (part) function 004, for the cell edge terminal belonging to the own base station, the cell edge terminal information including the base station information indicating from which base station the downlink transmission signal is an interference (the relevant The base station identification number that interferes with the terminal and the terminal identification number) are transmitted to other base stations and shared.

  The base station, including the outdoor base station, notifies the other base station of a number for identifying its own base station, and the adjacency relationship determination (part) function 009 uses the identification number obtained from the other base station to Determine the adjacency relationship of outdoor base stations. The inter-base station communication function 004 may use an interface defined by 3GPP.

  The transmission power value determination (unit) function 005 determines the transmission power value of the own base station based on the information about the cell edge terminal of the own base station and the information about the cell edge terminal reported from another base station.

  The database D1 stores data used for each function as shown in FIG.

  The terminals 21 to 24 receive the RSRP measurement (unit) function 101 for measuring the RSRP value for each base station, and a command to report the RSRP value from the base station, and the identification number of each base station and the received power of the downlink transmission signal An inter-base station communication (unit) function 102 for performing communication with each base station such as reporting a value (RSRP value) is provided.

  The outdoor base station 11 includes an inter-base station communication (unit) function 201 for communicating with each base station and each terminal, such as reporting the identification number to each base station at its own base station.

  (A) in FIG. 3 shows that a measured value (RSRP value) is measured a plurality of times (for example, five times) for each base station (indoor / outdoor base station) at each terminal, averaged, and from the outdoor terminal. The process which judges an "outdoor terminal" from a measured value (RSRP value) is shown. “Macro” indicates an outdoor base station. In addition, (b) shows a case where the outdoor terminal is temporarily hidden behind a shield against the macro, and (c) shows a case where the terminal enters the building and becomes an indoor terminal. Showing change. Further, (d) shows the number of times that the RSRP value from the macro has reached a predetermined value or more N times continuously for the outdoor terminal and (e).

FIG. 4 shows an example of data in the database D1 of the indoor base station. Database D1 contains
A threshold N1 (number of times) used to average the downlink signal power value from the base station;
A threshold C1 of a CINR (Carrier to Interference and Noise Ratio) value, which is a radio quality that is a reference for determining “cell edge terminal”;
A threshold C2 of downlink signal power from an outdoor base station serving as a reference for determining “outdoor terminal”;
A threshold value N2 of the number of times that the measured value of the downlink signal power from the outdoor base station measured at the terminal continuously exceeds that necessary to be determined as “outdoor terminal”,
Furthermore, the identification number of the terminal determined as “cell edge terminal” and “outdoor terminal”, the identification number of the base station that interferes with the terminal to which the downlink transmission signal belongs to its own base station, and others The identification number of the own base station for determining the adjacency relationship with the base station is stored.

  FIG. 5 shows an operation flowchart in the indoor base station in the first embodiment. After starting, the indoor base stations 01 and 02 start collecting downlink signal power measurement values (RSRP values) from the base stations around the terminals from the terminals belonging to the indoor base stations 01 and 02 at predetermined time intervals (step A1, A2: RSRP collection function 002). The RSRP value from each base station measured by each terminal is collected a predetermined number of times (step A3: RSRP collection function 002).

  An RSRP value from each base station measured by a predetermined number of terminals is averaged to obtain an average RSRP value from each base station in each terminal. In each terminal, radio quality is calculated from the largest average RSRP value and the second largest average RSRP value, and when the radio quality is equal to or less than a predetermined reference value (C1), the terminal is a “cell edge terminal”. The base station that gives the second largest average RSRP value judges that it is interfering with the terminal. Furthermore, from the RSRP value for the first predetermined number of times, a terminal whose RSRP value from the outdoor base station is equal to or greater than the second predetermined number of times that is smaller than the first predetermined number of times is described as “outdoor "Terminal". The determination result is stored in the database D1 with the terminal identification number (step A4: terminal type determination function 003).

  When there is a cell edge terminal among terminals belonging to itself, a terminal that is an outdoor terminal and is a cell edge terminal is not regarded as a cell edge terminal and is deleted from the database. If there is no cell edge terminal, or an outdoor terminal and no terminal that is a cell edge terminal, the contents of the existing database are not rewritten (steps A5, A6, A7: terminal type discrimination function 003).

  After executing the processing of steps A1 to A7, the contents of the database are shared with other base stations, and its own transmission power value is determined (step A8: transmission power value determination function 005, adjacency relationship determination function 009). The determination of the own transmission power value is executed by determining an increase in the transmission power value if, for example, the terminal has the most “cell edge terminals” than the adjacent indoor base station. The adjacency relationship between the base station and the other base station can be obtained by the adjacency determination function 009.

  Furthermore, it returns to step A1 and repeats a process.

  By performing the above processing, when controlling the transmission power value of the base station based on the presence status of the terminals distributed in the cell of the indoor base station, the terminals distributed outside the building are identified, and the transmission power value is determined. By performing the process of excluding from the terminal to be considered when controlling, the transmission power of the indoor base station is excessively increased, and the interference to the terminal belonging to the adjacent base station becomes large, or the base In order to avoid interference with a station, the transmission power of an adjacent base station is reduced, and it is possible to avoid a decrease in communication quality of a terminal belonging to the adjacent base station.

  Therefore, according to the present invention, since the transmission power value is appropriately determined in consideration of only the terminals existing indoors, indoor users using the femto base station can obtain good communication quality, and QoS (Quality of Service : Quality of service) is achieved. Furthermore, since the base station autonomously performs transmission power control, the operator can reduce the cost and traffic required for designing and operating the wireless area.

  This embodiment may be implemented in other types of base stations other than indoor base stations.

Embodiment 2. FIG.
6 is a diagram showing a configuration of a radio communication system including a base station and a control apparatus according to Embodiment 2 of the present invention. In the wireless communication system of FIG. 1, all the indoor base stations 01 and 02 and the outdoor base station 11 are communicably connected (wired connection) with the control device 31, and the control device 31 is connected to the base station with respect to each base station. The difference is that control including station data setting processing for station setting is performed. The control device 31 performs centralized management of information sharing between the base stations and the base stations performed in Embodiment 1, and performs transmission power setting control processing for all base stations.
All terminals can communicate with one of the base stations in the cell of the base station.

  FIG. 7 shows a block configuration diagram of each device in the wireless communication system of the second embodiment.

  In FIG. 7, the indoor base stations 01 and 02 include the following.

  The RSRP collection (part) function (or communication state information collection (part) function) 002 uses a terminal-to-terminal communication (part) function 001 to transmit each base station measured by the terminal from the terminal belonging to the base station. Collect RSRP values.

Based on the RSRP value collected from the terminal, the terminal type determination (unit) function 003 determines that the radio quality is equal to or lower than a predetermined reference value due to interference of downlink signals from other than the belonging base station or noise power. Whether or not it is a “cell edge terminal (terminal at the cell edge of the base station)” and “outdoor terminal” that belongs to its own base station and exists outside the building where it is installed Among the cell edge terminals belonging to the own base station, terminals that are also outdoor terminals are not regarded as cell edge terminals.
Then, using the inter-control device communication (unit) function 006, for the cell edge terminal belonging to the own base station, the cell edge terminal information including the base station information indicating which base station the downlink transmission signal is causing interference (in this case Report the identification number of the base station that interferes with the terminal and the identification number of the terminal) to the control device 31.

  The database D1 stores data used for each function as shown in FIG. 4, for example.

  The configurations of the terminals 21 to 24 are the RSRP measurement (unit) function 101 for measuring the RSRP value for each base station, the instruction to report the RSRP value from the base station, the reception of the identification number of each base station and the downlink transmission signal An inter-base station communication (unit) function 102 that performs communication with each base station, such as reporting a power value (RSRP value), is provided.

  The control device 31 is connected to all base stations and includes the following.

  The inter-base station communication (part) function 301 receives the number of terminals to be considered for transmission power control and the determination numbers of the base station and adjacent base stations with the indoor base station inter-controller communication function 006. Communication is performed such as notification of the station data setting including the transmission power value (the identification number of the base station that interferes with the terminal and the identification number of the terminal).

  The transmission power value determination control (unit) function 302 communicates with the base station using the inter-base station communication function 301. Based on the information on the cell edge terminals reported from the base station, Control including station data setting processing for station setting is performed.

  The adjacency relationship determination (part) function 303 includes data stored in the base station database D1 obtained from each base station necessary for transmission power setting control processing for each indoor base station, including outdoor base stations. Etc. are received from each base station, and the adjacent relationship between the indoor base station and the outdoor base station is determined using the data or the like.

  The database Da stores data and the like stored in the base station database D1 obtained from each base station, which is necessary for the transmission power setting control processing for each indoor base station.

  The outdoor base station 11 receives a command for notifying the identification number of the base station with the inter-base station communication function 301 of the control device 31, and communicates with the control device such as notifying the identification number of the own base station. The inter-control device communication (unit) function 202 is provided.

  FIG. 8 shows an operation flowchart in the indoor base station in the second embodiment, and FIG. 9 shows an operation flowchart in the control apparatus in the second embodiment. In FIG. 7, steps A1 to A7 are the same as those in the first embodiment, and after executing the processing of steps A1 to A7, the contents of the database D1 (the identification number of the base station that interferes with the terminal and the terminal (Including the information of the discrimination number) (step A′8: terminal type discrimination function 003). The reported contents may be accumulated in the database Da of the control device and converted into statistical information by statistical processing. Furthermore, it returns to step A1 and repeats a process.

  As shown in FIG. 9, the control device acquires the contents of the database D1 from all the connected base stations (step B1: transmission power value determination control function 302, adjacency determination function 303), and acquires the acquired database. Based on the contents, the transmission power setting processing of the indoor base station is executed (step B2: transmission power value determination control function 302, adjacency relationship determination function 303).

  The setting of the transmission power value is executed by, for example, instructing an increase in the transmission power value for an indoor base station having the largest number of “cell edge terminals” among adjacent indoor base stations. The transmission power setting process may also use statistical information included in the control device.

  By performing the above processing, when controlling the transmission power value of the base station based on the presence status of the terminals distributed in the cell of the indoor base station, the terminals distributed outside the building are identified, and the transmission power value is determined. By performing the process of excluding from the terminal to be considered when controlling, the transmission power of the indoor base station is excessively increased, and the interference to the terminal belonging to the adjacent base station becomes large, or the base In order to avoid interference with a station, the transmission power of an adjacent base station is reduced, and it is possible to avoid a decrease in communication quality of a terminal belonging to the adjacent base station.

  Therefore, according to the present invention, since the transmission power value is appropriately determined in consideration of only terminals existing indoors, indoor users using the femto base station can obtain good communication quality and achieve an improvement in QoS. Is done. Furthermore, since the transmission power of the base station is controlled autonomously, the operator can reduce the cost and traffic required for designing and operating the wireless area.

  Also, in the control device, statistical processing is performed by accumulating information obtained from the base station, and transmission power control is performed based on the statistical information, so that control in accordance with the presence status of the base station and the terminal is performed. Is feasible.

  This embodiment may be implemented in other types of base stations other than indoor base stations.

Embodiment 3 FIG.
The configuration of the wireless communication system including the base station and the control device according to the third embodiment of the present invention and the configuration of each device are the same as those of the second embodiment shown in FIGS.

  An example of the data in database D1 which the indoor base station in Embodiment 3 has is shown in FIG. The indoor base station according to the third embodiment is a threshold value that serves as a criterion for determining “outdoor terminals” that are not excluded from “cell edge terminals” in addition to the contents of the database D1 according to the first and second embodiments shown in FIG. And (average) transmission throughput value (throughput information from the base station to each terminal) from the base station to which the terminal belongs.

  FIG. 11 shows an operation flowchart in the indoor base station in the third embodiment, and FIG. 12 shows an operation flowchart in the control apparatus in the second embodiment. Steps A1, A3, A5 to A7, B1, and B2 are the same as those in the first and second embodiments. Step A'8 is the same as that in the second embodiment.

  After starting, the indoor base stations 01 and 02, from a terminal belonging to the indoor base stations 01 and 02, at a predetermined time interval, a measured value (RSRP value) of downlink signal power from each base station around the terminal and a base station which is communication state information The transmission bit rate from the terminal to the terminal is started (steps A1, A′2: RSRP collection function 002), and the RSRP value from each base station measured by the terminal and the base station to which it belongs, a predetermined number of times The transmission bit rate is collected (step A3: RSRP collection function 002).

An RSRP value from each base station measured by a predetermined number of terminals is averaged to obtain an average RSRP value from each base station in each terminal. In each terminal, radio quality is calculated from the largest average RSRP value and the second largest average RSRP value, and when the radio quality is equal to or lower than a predetermined reference value (C1), the terminal is determined to be a cell edge terminal. Then, the base station that gives the second largest average RSRP value determines that interference is given to the terminal. Further, the transmission bit rate from the base station to which the terminal belongs for a predetermined number of times in each terminal is averaged to obtain the average transmission bit rate from the base station to which the terminal belongs in each terminal.
Furthermore, from the RSRP value for the first predetermined number of times, the RSRP value from the outdoor base station is equal to or greater than the second predetermined number of times smaller than the first predetermined number of times, A terminal whose average transmission bit rate from the base station is a predetermined value or less is determined as an outdoor terminal. The determination result is stored in the database D1 (step A′4: terminal type determination function 003).

  When there is a cell edge terminal among terminals belonging to itself, a terminal that is an outdoor terminal and is a cell edge terminal is not regarded as a cell edge terminal and is deleted from the database. When there is no cell edge terminal or when there is no outdoor terminal and no cell edge terminal, the contents of the existing database are not rewritten (steps A5, A6, A7: terminal type discrimination function 003).

  After executing the processing of Steps A1 to A7, the contents of the database D1 (including the identification number of the base station causing interference to the terminal and the information of the identification number of the terminal) are reported to the control device 31 (Step A '8: Terminal type discrimination function 003). The reported contents may be accumulated in the database Da of the control device and converted into statistical information by statistical processing. Furthermore, it returns to step A1 and repeats a process.

  As shown in FIG. 12, the control device acquires the contents of the database D1 from all the connected base stations (step B1: transmission power value determination control function 302, adjacency determination function 303), and Based on the contents, the transmission power setting processing of the indoor base station is executed (step B2: transmission power value determination control function 302, adjacency relationship determination function 303).

The setting of the transmission power value is executed by, for example, instructing an increase in the transmission power value for an indoor base station having the largest number of “cell edge terminals” among adjacent indoor base stations.
The transmission power setting process may also use statistical information included in the control device.

  By performing the above processing, when controlling the transmission power value of the base station based on the presence status of the terminals distributed in the cell of the indoor base station, the terminals distributed outside the building are identified, and the transmission power value is determined. By performing the process of excluding from the terminal to be considered when controlling, the transmission power of the indoor base station is excessively increased, and the interference to the terminal belonging to the adjacent base station becomes large, or the base In order to avoid interference with a station, the transmission power of an adjacent base station is reduced, and it is possible to avoid a decrease in communication quality of a terminal belonging to the adjacent base station.

  Therefore, according to the present invention, since the transmission power value is appropriately determined in consideration of only terminals existing indoors, indoor users using the femto base station can obtain good communication quality and achieve an improvement in QoS. Is done. Further, by making a control determination using the transmission bit rate, it is possible to realize control more in accordance with the user's request. In addition to the transmission bit rate, applications that are frequently used (such as streaming) may be used, or may be used simultaneously with the transmission bit rate.

  This embodiment may be implemented in other types of base stations other than indoor base stations.

  It goes without saying that the present invention is not limited to the above embodiment and includes all possible combinations thereof.

  001 Inter-terminal communication function, 002 RSRP collection function (communication state information collection function), 003 Terminal type discrimination function, 004 Inter-base station communication function, 005 Transmission power value determination function, 006 Inter-controller communication function, 009 Adjacent relation determination function , 01, 02 Indoor base station, 11 Outdoor base station, 21-24 terminal, 31 Control device, 101 RSRP measurement function, 102 Inter-base station communication function, 201 Inter-base station communication function, 202 Inter-control device communication function, 301 base Inter-station communication function, 302 transmission power value determination control function, 303 adjacent relation determination function, D1, Da database.

Claims (10)

A plurality of base stations that can communicate with each other including an outdoor base station and an indoor base station, and a plurality of terminals that can communicate with the base station in a base station cell of any of the plurality of base stations. An indoor base station for a wireless communication system in which a plurality of base stations and a plurality of terminals communicate with each other using a signal including its own identification number,
From a terminal belonging to the indoor base station, a communication state information collecting unit that collects a downlink received power value of each base station measured at the terminal,
Based on the downlink received power value collected from the terminal and the CINR value correlated with the downlink received power value, the “cell edge terminal” whose radio quality is equal to or lower than a predetermined reference value and the indoor base station are installed. A base station that distinguishes the “outdoor terminal” existing outside the building and that is also the outdoor terminal among the cell edge terminals, and that interferes with the terminal that is regarded as the cell edge. A station type identification number, a terminal type identification unit that transmits the identification number of the terminal to another base station,
An adjacent relationship determination unit that determines the adjacent relationship between the indoor base station and the outdoor base station from the determination number in a signal from another base station;
A transmission power value determining unit that determines the transmission power value of the indoor base station based on the information of the cell edge terminal obtained in the indoor base station and the information of the cell edge terminal from another base station and the adjacency relationship;
Including an indoor base station. A plurality of base stations capable of communicating with each other, including an outdoor base station and an indoor base station;
A plurality of terminals capable of communicating with the base station in a base station cell of any of the plurality of base stations;
A wireless communication system in which the plurality of base stations and the plurality of terminals communicate with each other using a signal including its own identification number,
Each indoor base station is
A communication state information collecting unit that collects the downlink received power value of each base station measured at the terminal from the terminal belonging to the indoor base station;
Based on the downlink received power value collected from the terminal and the CINR value correlated with the downlink received power value, the “cell edge terminal” whose radio quality is equal to or lower than a predetermined reference value and the indoor base station are installed. A base station that distinguishes the “outdoor terminal” existing outside the building and that is also the outdoor terminal among the cell edge terminals, and that interferes with the terminal that is regarded as the cell edge. A station type identification number, a terminal type identification unit that transmits the identification number of the terminal to another base station,
An adjacent relationship determination unit that determines the adjacent relationship between the indoor base station and the outdoor base station from the determination number in a signal from another base station;
A transmission power value determining unit that determines the transmission power value of the indoor base station based on the information of the cell edge terminal obtained in the indoor base station and the information of the cell edge terminal from another base station and the adjacency relationship;
A wireless communication system comprising: Instead of the transmission power value determination unit and the adjacency determination unit of each indoor base station, comprising a control device connected to all the base stations,
The terminal type determination unit of each indoor base station transmits information of the cell edge terminal to the control device,
The control device is
An adjacent relationship determination unit that determines the adjacent relationship between the indoor base station and the outdoor base station using the determination number in the signal from each base station;
A transmission power value determination control unit that performs transmission power setting control processing for determining the transmission power value of each indoor base station and transmitting it to each indoor base station based on the information on the cell edge terminal from each base station and the adjacent relationship;
The wireless communication system according to claim 2, comprising:   The terminal type discriminating unit calculates the radio quality of the terminal from the largest measured value and the second largest measured value in each terminal, and if the radio quality is equal to or less than a predetermined reference, the terminal type cell edge 4. The wireless communication system according to claim 2, wherein the base station that determines that the terminal is a terminal and that gives the second largest measurement value determines that the terminal is causing interference. The communication state information collection unit collects downlink received power values measured at the terminal a predetermined number of times,
The terminal type determination unit determines, as an outdoor terminal, a terminal whose measured value of the downlink received power value of the outdoor base station is equal to or greater than a predetermined number of the measured values for a predetermined number of times,
The wireless communication system according to claim 2, wherein the wireless communication system is a wireless communication system.   The radio communication system according to claim 2, wherein the transmission power value determination unit increases the transmission power when the cell edge terminal is the largest among a plurality of adjacent indoor base stations.   The wireless communication system according to claim 3, wherein the transmission power value determination control unit increases transmission power of an indoor base station having the largest number of cell edge terminals among a plurality of adjacent indoor base stations.   The transmission power value determination control unit accumulates information reported from the base station, performs statistical processing to generate statistical information, and performs transmission power setting control processing using the statistical information. The wireless communication system described. The communication state information collection unit further collects throughput information from the base station to each terminal,
Of the cell edge terminals belonging to the base station, the terminal type determination unit is an outdoor terminal, and a terminal whose requested throughput value is a predetermined value or less is not regarded as a cell edge terminal. The wireless communication system according to claim 3. A plurality of base stations that can communicate with each other including an outdoor base station and an indoor base station, and a plurality of terminals that can communicate with the base station in a base station cell of any of the plurality of base stations. In a wireless communication system in which a base station and a plurality of terminals communicate using a signal including their own identification numbers,
A communication state information collecting step for collecting the downlink received power value of each base station measured at the terminal from the terminal belonging to the indoor base station;
Based on the downlink received power value collected from the terminal and the CINR value correlated with the downlink received power value, the “cell edge terminal” whose radio quality is equal to or lower than a predetermined reference value and the indoor base station are installed. A base station that distinguishes the “outdoor terminal” existing outside the building and that is also the outdoor terminal among the cell edge terminals, and that interferes with the terminal that is regarded as the cell edge. A station type identification number, a terminal type determination step for transmitting the terminal identification number to another base station, and
Adjacent relationship determination step of determining the adjacent relationship between the indoor base station and the outdoor base station from the determination number in the signal from another base station,
A transmission power value determining step for determining a transmission power value of the indoor base station based on the information on the cell edge terminal obtained at the indoor base station and the information on the cell edge terminal from another base station and the adjacency relationship;
A control method for a wireless communication system, comprising:

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