JP2013065943A - Wireless communication system and transmission power determination method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily determine transmission power of an indoor base station according to a setting environment of a femto base station.SOLUTION: A femto base station 11a comprises: a reception power measurement unit for measuring reception power from a macro base station 10; and a base station control unit which transmits to a wireless base station monitoring server 4 a measurement result of reception power in its own station or a UE 20b existing in the station from the macro base station 10, and performs transmission by reported transmission power. The wireless base station monitoring server 4 comprises: an initial transmission power determination table indicating a relation between the reception power measurement result and initial transmission power in the femto base station 11a; a database for storing the measurement result of the reception power in the UE 20b from the macro base station; and a server control unit for performing control to determine transmission power in the femto base station 11a on the basis of the reception power measurement result received from the femto base station 11a, and to report the determined transmission power.

Description

  The present invention relates to a radio communication system including a femto base station installed indoors and a macro base station installed outdoors.

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 As one of radio access technologies, standardization of LTE (Long Term Evolution) and LTE-Advanced has been performed. 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 radio 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 radius of a radio cell is several tens of meters or less.

  Thus, since the size of the radio cell differs between the outdoor base station and the indoor base station, the cell configuration generally includes the indoor base station in the radio cell of the outdoor base station. In this configuration, when the outdoor base station and the indoor base station use the same frequency, if the transmission power of the indoor base station is set excessively, interference with the radio cell of the outdoor base station becomes excessive and the communication capacity deteriorates. On the contrary, if the transmission power of the indoor base station is set too low, the service cannot be received within the wireless cell of the indoor base station. In particular, the indoor base station that is fixed at a specific position by recognizing the received power of the outdoor base station is smaller due to the location where the indoor base station is installed, such as the relationship with the location of the walls and windows of the building, When the transmission power is determined based on the reception power of the outdoor base station, there arises a problem that the radius of the radio cell is extremely small.

  Therefore, in the following Patent Document 1, when determining the transmission power of a radio base station installed indoors, the received electric field strength of a radio signal from an outdoor radio base station is measured, and further, an indoor radio base station is installed. A technique for determining the maximum transmission power of an indoor radio base station by estimating a building intrusion loss due to a building wall or the like has been disclosed. Further, in Patent Document 2 below, the result of theoretical simulation using the measured value of the received power of the radio base station measured by a mobile phone and the estimated value of the received power at the observation point by the theoretical simulation using the propagation model. A technique for determining an appropriate transmission power of a radio base station by correcting the value with an actually measured value is disclosed.

JP 2010-219918 A JP 2011-019109 A

  However, according to the above conventional technique (Patent Document 1), map information and radio base station antenna setting information are used for propagation estimation. Use simple models and ray tracing. Therefore, in order to determine the transmission power of an indoor radio base station installed in an unspecified place, the above-mentioned map information and radio base station antenna setting information must all be stored in the database. was there.

  Further, according to the conventional technique (Patent Document 2), there is a problem that the difference between the propagation environment and the propagation model in a complicated indoor environment greatly depends on the transmission power determination of the radio base station.

  The present invention has been made in view of the above, and an object of the present invention is to provide a wireless communication system that can easily determine the transmission power of an indoor base station according to a setting environment.

  In order to solve the above-described problems and achieve the object, the present invention provides a wireless communication system capable of changing the transmission power of a femto base station installed indoors, wherein the wireless communication system is installed outdoors. The femto base station, the femto base station, a terminal that can move between the base stations, and a radio base station monitoring server that determines and adjusts the transmission power of the femto base station. Base station communication means for communicating with the macro base station, the terminal, and the radio base station monitoring server, received power measuring means for measuring received power from the macro base station, and the local station or the local station Transmitting the reception power measurement result from the macro base station in the terminal to the radio base station monitoring server, and using the transmission power notified from the radio base station monitoring server, a downlink signal is transmitted. Base station control means for performing communication control, wherein the radio base station monitoring server includes server communication means for communicating with the femto base station, received power measurement results and initial transmission power at the femto base station. An initial transmission power determination table showing a relationship; storage means for storing a reception power measurement result from a macro base station in the terminal; and the macro base station in the femto base station or a terminal residing in the femto base station Server control means for determining the transmission power in the femto base station based on the received power measurement result from the base station, and performing control for notifying the determined transmission power to the femto base station.

  According to the present invention, it is possible to easily determine the transmission power of the indoor base station according to the setting environment.

FIG. 1 is a diagram illustrating a configuration example of a wireless communication network. FIG. 2 is a diagram illustrating a radio area of each base station. FIG. 3 is a diagram illustrating a configuration example of a radio base station monitoring server. FIG. 4 is a diagram illustrating a configuration example of a femto base station. FIG. 5 is a sequence diagram illustrating an operation of determining the transmission power of the femto base station. FIG. 6 is a diagram illustrating an installation environment of the femto base station at the start of measurement of received power of the surrounding macro base station. FIG. 7 is a diagram illustrating a transmission power determination table of the femto base station. FIG. 8 is a diagram illustrating an installation environment of the femto base station at the start of correction. FIG. 9 is a diagram illustrating a correction value determination table. FIG. 10 is a diagram illustrating a collection state of UE measurement results stored in the database. FIG. 11 is a diagram illustrating a transmission power determination table of the femto base station.

  Embodiments of a wireless communication system according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
In this embodiment, as an example, the case of application to a wireless communication network of the LTE (Long Term Evolution) defined by 3GPP, which is one of standardization organizations (3 ^rd Generation Partnership Project). Note that the present invention can also be applied to wireless communication networks other than LTE, such as 3G.

  FIG. 1 is a diagram illustrating a configuration example of a wireless communication network according to the present embodiment. The LTE wireless network includes E-UTRAN (Evolved Universal Terrestrial Radio Access Network) 1, UE (User Equipment) 2, EPC (Evolved Packet Core) 3, radio base station monitoring server 4, HeNB GW (Home eNodeB). Gateway) 5.

  The E-UTRAN 1 includes a macro base station 10 installed outdoors and femto base stations 11a and 11b installed indoors.

  The UE 2 is connected to the E-UTRAN 1 using the LTE radio access communication scheme, and includes a UE 20 a connected to the macro base station 10 and a UE 20 b connected to the femto base station 11 a.

  The EPC 3 is a mobility management entity (MME) 30 that manages the mobility of the UE 2, an S-GW (Serving Gateway) 31 that provides a gateway function for IP communication, a P-GW (Packet Data Network Gateway) 32, and a user subscription HSS (Home Subscriber Server) 33 for managing subscriber information.

  The radio base station monitoring server 4 determines and adjusts the transmission power of the femto base stations 11a and 11b.

  The HeNB GW 5 functions as a gateway between the femto base station 11b and the EPC 3.

  The femto base stations 11a and 11b can be connected to the EPC 3 via the HeNB GW 5 and can be directly accommodated in the EPC 3.

  Next, the radio area of each base station will be described. FIG. 2 is a diagram illustrating a radio area of each base station. The relationship between the radio area 40 in the macro base station 10, the radio area 50a in the femto base station 11a, and the radio area 50b in the femto base station 11b is shown. The femto base stations 11 a and 11 b belong to at least one macro base station 10.

  The femto base stations 11a and 11b are connected to the radio base station monitoring server 4 that determines the transmission power of the femto base stations 11a and 11b. The radio base station monitoring server 4 includes an algorithm for determining the transmission power of the femto base stations 11a and 11b and a database 60 for storing measurement information reported from the femto base stations 11a and 11b. The database 60 may be implemented in the femto base station 10.

  Next, the configuration of the radio base station monitoring server 4 will be described. FIG. 3 is a diagram illustrating a configuration example of the radio base station monitoring server 4. As an example, a configuration including the database 60 will be described. The radio base station monitoring server 4 includes a server communication unit 401, an initial transmission power determination table 402, a database 60, and a server control unit 403. The server communication unit 401 communicates with the femto base stations 11a and 11b. The initial transmission power determination table 402 is a table used when determining the initial transmission power of the femto base stations 11a and 11b. The server control unit 403 controls communication with the femto base stations 11a and 11b, and determination and correction of transmission power of the femto base stations 11a and 11b.

  Next, the configuration of the femto base station 11a will be described. FIG. 4 is a diagram illustrating a configuration example of the femto base station 11a. The femto base station 11 a includes a base station communication unit 101, a received power measurement unit 102, and a base station control unit 103. The base station communication unit 101 communicates with the macro base station 10, the UE 20b, the radio base station monitoring server 4, and the like. The received power measuring unit 102 measures received power from the macro base station 10. The base station control unit 103 controls communication with each device, reception power measurement, transmission power setting, and the like. Although the femto base station 11a has been described, the femto base station 11b has the same configuration.

  Next, an operation for determining the transmission power of the femto base stations 11a and 11b in the wireless communication system shown in FIG. 1 will be described. FIG. 5 is a sequence diagram illustrating an operation of determining the transmission power of the femto base station. As an example, an operation for determining the transmission power of the femto base station 11a will be described.

  First, in the femto base station 11a installed indoors, the received power measurement unit 102 starts measuring the neighboring macro base station received power in order to determine the initial transmission power before transmitting the radio wave (step S1). FIG. 6 is a diagram illustrating an installation environment of the femto base station 11a at the start of measurement of received power of the surrounding macro base station. The femto base station 11a is installed indoors and indicates that it is connected to the macro base station 10 and the radio base station monitoring server 4. Moreover, it shows that there is a window between the femto base station 11a and the macro base station 10. Here, the macro base station 10 is a peripheral macro base station to be measured.

  In the femto base station 11a, the base station communication unit 101 sends the measurement result of RSRP (Reference Signal Received Power), which is the measured received power of the macro base station 10, to the radio base station monitoring server 4 as a radio base station received power measurement report. Transmit (step S2).

  In the radio base station monitoring server 4, the server communication unit 401 receives the measurement result, and the server control unit 403 refers to the initial transmission power determination table 402 of the femto base station shown in FIG. An initial transmission power is determined (step S3). FIG. 7 is a diagram illustrating a configuration example of the initial transmission power determination table 402. For example, when the macro base station reception power is smaller than −100 dBm, it indicates that the transmission power is set to −100 dBm. At this time, in the radio base station monitoring server 4, transmission power obtained by adding an offset value to the transmission power value set in the table of FIG. 7 in order to avoid the radio cell becoming small according to the measurement result of the femto base station 11 a. Use the value as the initial transmission power. That is, once the initial transmission power is set large. For example, when the macro base station received power is smaller than −100 dBm, it indicates that an offset value of 15 dB is added.

  In the radio base station monitoring server 4, the server communication unit 401 notifies the femto base station 11a of the determined initial transmission power (transmission power after offset) by the transmission power setting notification (step S4).

  In the femto base station 11a, the base station communication unit 101 receives the transmission power setting notification from the radio base station monitoring server 4, and the base station control unit 103 transmits a downlink signal using the determined transmission power value. Is started (step S5).

  Subsequently, in the wireless communication system, the determined initial transmission power of the femto base station 11a is corrected using measurement information from the UE 20b (herein, a mobile phone). FIG. 8 is a diagram illustrating an installation environment of the femto base station 11a at the start of correction. Assume that a user having a mobile phone (UE 20b) is moving indoors where the femto base station 11a is installed.

  First, the radio base station monitoring server 4 notifies the femto base station 11a of a transmission power setting correction request from the server communication unit 401 under the control of the server control unit 403 (step S6).

  In the femto base station 11a, the base station communication unit 101 receives the transmission power setting correction request, and is controlled by the base station control unit 103 to the UE 20b located in the femto base station 11a by RRC from the base station communication unit 101. Then, the measurement of the reception power of the macro base station 10 which is a neighboring macro base station is instructed (step S7).

  The UE 20b instructed to start measurement measures the received power of the macro base station 10 (step S8), and transmits the measurement result to the femto base station 11a by RRC (step S9).

  In the femto base station 11a, the base station communication unit 101 receives the measurement result of the macro base station 10 from the UE 20b, and is controlled by the base station control unit 103 from the base station communication unit 101 based on the radio base station received power measurement report. The measurement result in the UE 20b is transmitted to the radio base station monitoring server 4 (step S10).

  In the radio base station monitoring server 4, the server communication unit 401 receives the measurement result of the UE 20b from the femto base station 11a, and the server control unit 403 stores the measurement result in the database 60. Then, the acquisition is continued until the conditions of “number of samples necessary for determining transmission power” and “collection time of measurement results from mobile phone” set in the radio base station monitoring server 4 are satisfied. The “number of samples necessary for determining transmission power” is the number of samples for obtaining a sufficiently high reliability when the average value of measurement results is calculated as described later. The “collection time of measurement results from the mobile phone” is defined to ensure a collection time of a predetermined time or more so that the collection time is not concentrated in a short time. Therefore, the radio base station monitoring server 4 continues the acquisition until these two conditions are satisfied. In the radio base station monitoring server 4, these two conditions may be set / held by the server control unit 403, or may be held by the database 60.

  Next, the magnitude of the correction value based on the measurement result of the UE 20b will be described. FIG. 9 is a diagram illustrating a correction value determination table. The correction value determination table includes macro base station received power and correction values. Here, the macro base station received power indicates the received power in the UE 20b. For example, when the average value of the reception power measurement results in the UE 20b is −100 dBm or less, this indicates that the initial transmission power (transmission power after offset) of the femto base station 11a is corrected by +15 dB. The radio base station monitoring server 4 may hold the correction value determination table shown in FIG. 9 in the server control unit 403 or in the database 60.

  FIG. 10 is a diagram showing a collection state of measurement results of received power of the UE 20b stored in the database 60 in the radio base station monitoring server 4. FIG. 10A shows the case where the received power from the macro base station 10 is large, and FIG. 10B shows the case where the received power from the macro base station 10 is small.

  In the radio base station monitoring server 4, the server control unit 403 calculates the average value of the measurement results of the UE 20b stored in the database 60 in order to determine the transmission power correction value of the femto base station 11a from the measurement result of the UE 20b. Then, the server control unit 403 obtains a correction value for the initial transmission power of the femto base station 11a from the relationship between the average value and FIG. 9, and adds the correction value to the initial transmission power determined in step S3. The corrected transmission power is determined (step S11).

  In the radio base station monitoring server 4, the server communication unit 401 notifies the femto base station 11a of the transmission power added with this correction value by the transmission power setting notification (step S12).

  In the femto base station 11a, the base station communication unit 101 receives the transmission power setting notification, and the base station control unit 103 updates the operating transmission power (initial transmission power) to the corrected transmission power (step S13). ). Thereby, in the femto base station 11a, it is possible to transmit a downlink signal with transmission power corresponding to an environment in which the own station is installed.

  As described above, in the femto base station 11a, the base station control unit 103 transmits the reception power measurement result from the macro base station 10 in the own station or the UE 20b located in the own station to the radio base station monitoring server 4, and the radio Control to transmit a downlink signal using the transmission power notified from the base station monitoring server 4 is performed. Further, in the radio base station monitoring server 4, the server control unit 403 transmits the femto base station 11a based on the received power measurement result from the macro base station 10 in the femto base station 11a or the UE 20b located in the femto base station 11a. Control is performed to determine the power and notify the determined transmission power to the femto base station 11a.

  In the determination of the correction value of the transmission power, the average value of the measurement results of the UE 20b is used, but the present invention is not limited to this. For example, a maximum value or a center value (an intermediate value between the maximum value and the minimum value) may be used. Even in this case, an equivalent effect can be obtained.

  As described above, in the present embodiment, in the wireless communication system, the wireless base station monitoring server performs initial transmission power of the femto base station based on the measurement result of the received power from the macro base station measured by the femto base station. After that, the radio base station monitoring server collects reception power measurement results for the macro base station from the UE moving in the indoor area where the femto base station is installed, and based on the UE reception power measurement results, The initial transmission power of the base station was corrected. Thereby, the downlink transmission power of the femto base station can be set according to the installation environment.

  In the present embodiment, the radio base station monitoring server 4 determines the transmission power of the femto base station to be connected. However, the present invention is not limited to this. For example, each femto base station 11a, 11b includes the tables shown in FIG. 7 and FIG. 9, respectively, so that the reception power of the macro base station 10 measured by the local station and the UE 20b existing in the local station have measured. It is also possible to determine the transmission power of the own station based on the reception power of the macro base station 10.

Embodiment 2. FIG.
In the first embodiment, when correcting the transmission power of the femto base station 11a, the average value of the reception power measurement results from the macro base station 10 in the UE 20b (mobile phone) is used. In the present embodiment, the initial power determination table to be used is switched based on the position set when the femto base station 11a is installed. A different part from Embodiment 1 is demonstrated.

  In the present embodiment, in order to specify the position where the femto base station 11a is installed, a reference position (for example, 3 m) from the window of the building is provided. Then, when the installation position of the femto base station 11a is closer to the window environment than the reference position, the radio base station monitoring server 4 selects an initial transmission power determination table that gives a correction value for the window environment, and the femto base station When the installation position of 11a is the reference position, an initial transmission power determination table that gives a correction value for the reference position is selected, and when the installation position of the femto base station 11a is far from the reference position or in a windowless environment In this case, an initial transmission power determination table that gives a correction value for a windowless environment is selected.

  FIG. 11 is a diagram illustrating an initial transmission power determination table 402 of the femto base station included in the radio base station monitoring server 4. The femto base station initial transmission power determination table 402 includes three tables: (a) a window-side environment, (b) a reference environment, and (c) a windowless environment. Each table includes macro base station reception power, transmission power, and adjustment values. For example, when the femto base station 11a is installed at a position 2 m from the window and the reception power from the macro base station 10 is smaller than −100, (a) the transmission power is adjusted to −100 dBm by referring to the table of the window environment. Indicates that the value is -15 dB.

  In the radio base station monitoring server 4, when the installation position of the femto base station 11a is in a window environment, the server control unit 403 sets a transmission power value in order to reduce interference with the outdoor base station (macro base station 10). A correction value to decrease is given. On the other hand, when the installation position of the femto base station 11a is a windowless environment, there is no need to consider interference with the outdoor base station (macro base station 10), so the transmission power value is increased to secure an indoor area. The correction value to be given is given.

  If it demonstrates using the flowchart of FIG. 5, in the femto base station 11a, the reception power from the macro base station 10 will be measured (step S1), and the positional information on the own station will be transmitted together with the measurement result (step S2). The radio base station monitoring server 4 determines the initial transmission power using the initial transmission power determination table 402 corresponding to the received position information (Step S3), and transmits the determined initial transmission power to the femto base station 11a (Step S3). S4). Then, the femto base station 11a starts transmission of the downlink signal using the notified initial transmission power (step S5). In the present embodiment, the transmission power determination process is completed by the above process.

  As described above, in the present embodiment, in the radio communication system, the femto base station sets the installation location of the own station in advance, and transmits the position information together with the measurement result of the received power to the radio base station monitoring server. The radio base station monitoring server includes a plurality of initial transmission power determination tables and corrects transmission power using the initial transmission power determination table corresponding to the installation position of the femto base station. Thereby, the initial transmission power of the femto base station can be determined according to the installation environment of the femto base station.

  As described above, the wireless communication system according to the present invention is useful for a system including a plurality of base stations, and is particularly suitable for a system including a small base station.

1 E-UTRAN
2 UE
3 EPC
4 Radio base station monitoring server 5 HeNB GW
10 Macro base station 11a, 11b Femto base station 30 MME
31 S-GW
32 P-GW
33 HSS
40 Wireless area (macro base station 10)
50a Wireless area (Femto base station 11a)
50b Wireless area (Femto base station 11b)
60 Database 101 Base station communication unit 102 Received power measurement unit 103 Base station control unit 401 Server communication unit 402 Initial transmission power determination table 403 Server control unit

Claims (15)

A wireless communication system capable of changing the transmission power of a femto base station installed indoors,
The wireless communication system includes a macro base station installed outdoors, the femto base station, a terminal that can move between the base stations, and a radio base station monitoring server that determines and adjusts transmission power of the femto base station. When preparing
The femto base station is
Base station communication means for communicating with the macro base station, the terminal, and the radio base station monitoring server;
Received power measuring means for measuring received power from the macro base station;
Transmits the reception power measurement result from the macro base station in the local station or a terminal located in the local station to the radio base station monitoring server, and uses the transmission power notified from the radio base station monitoring server to transmit the downlink signal. Base station control means for controlling transmission;
With
The radio base station monitoring server is
Server communication means for communicating with the femto base station;
An initial transmission power determination table indicating a relationship between a reception power measurement result and initial transmission power in the femto base station;
Storage means for storing received power measurement results from the macro base station in the terminal;
The transmission power at the femto base station is determined based on the received power measurement result from the macro base station in the femto base station or a terminal located in the femto base station, and the determined transmission power is notified to the femto base station Server control means for performing control,
A wireless communication system comprising: As a result of transmitting the reception power measurement result from the macro base station to the radio base station monitoring server, the base station control means starts transmission using the initial transmission power notified from the radio base station monitoring server, In addition, as a result of transmitting the reception power measurement result from the macro base station a plurality of times at the terminal located in the local station to the radio base station monitoring server, it is transmitted to the corrected transmission power notified from the radio base station monitoring server. Control to update the power,
The server control means determines an initial transmission power of the femto base station from a reception power measurement result in the femto base station based on the initial transmission power determination table, and notifies the femto base station of the initial transmission power. Determining the corrected transmission power of the femto base station using correction values obtained from a plurality of received power measurement results from the macro base station, and performing control to notify the determined transmission power to the femto base station;
The wireless communication system according to claim 1. In the initial transmission power determination table, when an offset value set for each reception power measurement result in the femto base station is provided,
The server control means adds an offset value based on a reception power measurement result in the femto base station when determining the initial transmission power.
The wireless communication system according to claim 2. The server control unit obtains a correction value from an average value of received power measurement results from the macro base station in the plurality of received terminals.
The wireless communication system according to claim 2, wherein the wireless communication system is a wireless communication system. The server control unit obtains a correction value from an intermediate value between the maximum value and the minimum value of the received power measurement results from the macro base station in the plurality of received terminals.
The wireless communication system according to claim 2, wherein the wireless communication system is a wireless communication system. A wireless communication system capable of changing the transmission power of a femto base station installed indoors,
The wireless communication system includes a macro base station installed outdoors, the femto base station, a terminal that can move between the base stations, and a radio base station monitoring server that determines and adjusts transmission power of the femto base station. When preparing
The femto base station is
Base station communication means for communicating with the macro base station and the radio base station monitoring server;
Received power measuring means for measuring received power from the macro base station;
The location information indicating the environment in which the local station is installed and the reception power measurement result from the macro base station are transmitted to the radio base station monitoring server, and the initial transmission power notified from the radio base station monitoring server is used for downloading. Base station control means for performing control to start signal transmission;
The radio base station monitoring server is
Server communication means for communicating with the femto base station;
In accordance with the position information, a plurality of initial transmission power determination tables indicating a relationship between a reception power measurement result and initial transmission power in the femto base station,
Server control means for performing control to determine the initial transmission power of the femto base station from the reception power measurement result in the femto base station based on the initial transmission power determination table corresponding to the position information and to notify the femto base station When,
A wireless communication system comprising: When the reference position is a position that is a specified distance away from the window provided in the building,
The position information is information that compares the reference position and the distance between the position where the femto base station is installed and the window,
The wireless communication system according to claim 6. In the plurality of initial transmission power determination tables, when the position of the femto base station is closer to the window than the reference position, correction is performed to reduce the transmission power, and the position of the femto base station is changed from the window to the reference position. Including the correction value for correcting to increase the transmission power when far away,
The wireless communication system according to claim 7. A transmission power determination method in a wireless communication system capable of changing the transmission power of a femto base station installed indoors, wherein the wireless communication system includes a macro base station installed outdoors, the femto base station, and each base station When comprising a terminal that can move between and a radio base station monitoring server that determines and adjusts the transmission power of the femto base station,
The femto base station measures the received power from the macro base station, and transmits the measurement result of the received power in the own station to the radio base station monitoring server; and
The radio base station monitoring server determines an initial transmission power of the femto base station from a received power measurement result in the received femto base station based on an initial transmission power determination table included in the radio base station monitoring server, and determines the initial transmission power as the femto An initial transmission power determination step for notifying the base station;
The femto base station starts transmitting a downlink signal using the notified initial transmission power; and
A correction request step in which the radio base station monitoring server notifies the femto base station of a transmission power setting correction request;
The femto base station instructs a terminal residing in the own station to measure the received power from the macro base station, and the received power measurement result from the macro base station in the terminal received from the terminal a plurality of times Terminal reception power reporting step for transmitting to the radio base station monitoring server,
The radio base station monitoring server determines a corrected transmission power in the femto base station using correction values obtained from a plurality of reception power measurement results from a macro base station in the terminal, and the corrected transmission power is determined to be the femto base. A transmission power correction step to notify the station;
The femto base station updates the transmission power to the notified corrected transmission power, a transmission power update step,
Including a transmission power determination method. In the initial transmission power determination table, when an offset value set for each reception power measurement result in the femto base station is provided,
In the initial transmission power determination step, when determining the initial transmission power, an offset value is added based on a reception power measurement result in the femto base station.
The transmission power determination method according to claim 9. In the transmission power correction step, a correction value is obtained from an average value of reception power measurement results from the macro base station in the plurality of received terminals.
The transmission power determination method according to claim 9 or 10, wherein: In the transmission power correction step, a correction value is obtained from an intermediate value between the maximum value and the minimum value of the reception power measurement results from the macro base station in the plurality of received terminals.
The transmission power determination method according to claim 9 or 10, wherein: A transmission power determination method in a wireless communication system capable of changing the transmission power of a femto base station installed indoors, wherein the wireless communication system includes a macro base station installed outdoors, the femto base station, and each base station When comprising a terminal that can move between and a radio base station monitoring server that determines and adjusts the transmission power of the femto base station,
The femto base station measures the received power from the macro base station and transmits the received power measurement result at the own station to the radio base station monitoring server together with the position information where the own station is installed. Steps,
When the radio base station monitoring server includes a plurality of initial transmission power determination tables according to the position information, the received power measurement at the received femto base station is performed based on the initial transmission power determination table corresponding to the position information. An initial transmission power determining step of determining an initial transmission power of the femto base station from a result, and notifying the initial transmission power to the femto base station;
The femto base station starts transmitting a downlink signal using the notified initial transmission power; and
Including a transmission power determination method. When the reference position is a position that is a specified distance away from the window provided in the building,
The position information is information that compares the reference position and the distance between the position where the femto base station is installed and the window,
The transmission power determination method according to claim 13. In the plurality of initial transmission power determination tables, when the position of the femto base station is closer to the window than the reference position, correction is performed to reduce the transmission power, and the position of the femto base station is changed from the window to the reference position. Including the correction value for correcting to increase the transmission power when far away,
The transmission power determination method according to claim 14.

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