JP5473860B2 - Mobile communication system and radio base station power saving control method - Google Patents

Description

  The present invention relates to a mobile communication system and a power saving control method for a radio base station, and in particular, a plurality of radio base stations and a radio base station that is surrounded by a cover area of those radio base stations. A mobile communication system comprising a radio base station arranged outside the cover area of the mobile station and a radio base station surrounded by the cover areas of the plurality of radio base stations and arranged outside the cover area of the radio base stations The present invention relates to a power saving control method.

  In general, a radio base station that constitutes a mobile communication system constantly transmits radio waves in its cover area, and therefore always requires power supply. As a conventional technique for reducing the waste of transmission power of a radio base station with low communication traffic when a plurality of base stations cover one area, for example, a technique described in Patent Document 1 is known. Yes. This prior art is intended to save power in the entire mobile communication system by cutting off the power of a radio base station with low communication traffic and stopping its operation.

  As an example of a mobile communication system to which the above-described conventional technology is applied, for example, there is a mobile communication system configured by LTE as a macro cell and WiMAX as a micro cell. This mobile communication system is configured so that a plurality of radio base stations of different communication schemes cover one area, and the terminals using the mobile communication system have the above-described WiMAX base stations and LTE bases having different communication schemes. It is configured to receive a service using both stations. That is, this mobile communication system is configured by deploying LTE in a wide area and arranging WiMAX in spots in stations and buildings.

  Since recent mobile communication systems are configured to correspond to a plurality of standards and frequency bands, radio waves transmitted between mobile communication systems do not interfere with each other. As such mobile communication systems become multi-standard and multi-band, radio base stations will not be caught by radio wave interference, so there is a possibility that they will be operated using their transmission power to the maximum. is there.

  Currently, development of a wireless router that automatically selects an optimal communication line from a WiMAX base station and connects to the Internet is underway. This wireless router provides a service that automatically selects and connects the optimum radio wave of LTE, which is a macro cell, to WiMAX, which is a micro cell. As a service that makes it difficult to use the network from a personal computer or mobile terminal in the near future. The spread is expected. In addition, the spread of dual terminals capable of using such services is also expected. In such a situation, paying attention to the transmission power consumption from the viewpoint of integrating a plurality of mobile communication systems using different communication schemes, it is arranged in a place where a plurality of radio base stations are operating redundantly in one area. It can be seen that there is a waste of transmission power of the wireless base station.

JP 2002-204478 A

  The mobile communication system configured by applying the above-described conventional technology is intended to save power by cutting off the power of the radio base station, but the area where the terrain is curved, such as between the buildings or between the mountains, When a wireless base station installed at a location outside the boundary of the macro cell is targeted for power interruption, a problem arises that an insensitive area of radio waves is generated.

  An object of the present invention is to reduce the power consumption of a radio base station having a second communication method installed at a location outside the boundary of the coverage area of a plurality of radio base stations having the first communication method. An object of the present invention is to provide a mobile communication system and a radio base station power saving control method that can be performed without generating a dead area.

According to the present invention, the object is to provide a mobile communication system in which a plurality of radio base stations having first and second communication schemes are distributed in one area to provide services to subscriber terminals. A plurality of radio base stations having a scheme, and a second area that is surrounded by a plurality of cover areas by the plurality of radio base stations and that is located outside the boundary of the cover areas A radio base station having a communication scheme; a first center facility for managing a plurality of radio base stations having the first communication scheme; and a second managing a plurality of radio base stations having the second communication scheme. Center facility, and the first center facility collects information on the presence / absence of operation as information on the operation status of each of the plurality of radio base stations having the first communication method, and stores the information in the second center facility. Send the second Base station operation status collection means for storing in a database provided in the center facility, wherein the second center facility stores connection call count data of each of a plurality of radio base stations having the second communication method. Call connection information collection / ratioing means for calculating a ratio between the collected number of connected calls and the call number upper limit threshold predetermined for each of a plurality of radio base stations having the second communication method; And the control call number ratio threshold value, which is a ratio of the number of connected calls and the call number upper limit threshold value determined in advance for each of the plurality of radio base stations having the second communication method, Threshold determination / station identification means for determining whether to lower or increase the transmission power of each of a plurality of radio base stations having a communication method, and each of a plurality of radio base stations having the first communication method stored in the database Depending on whether or not there is operation Neighboring station status determining means for determining information on the presence / absence of operation of each of the plurality of radio base stations having the first communication scheme adjacent to each of the plurality of radio base stations having the second communication scheme; Information on whether to reduce or increase the transmission power of each of the plurality of radio base stations having the second communication method and information on whether each of the adjacent plurality of radio base stations having the first communication method is in operation Referring to this, it is achieved by including power control means for controlling the transmission power of each of the plurality of radio base stations having the second communication method to be a predetermined lower limit value or upper limit value .

  According to the present invention, transmission power required for a radio base station can be controlled according to the usage rate of the radio base station, which is a call connection amount of a WiMAX base station that is a radio base station to be controlled. Therefore, it is possible to achieve power saving as the entire mobile communication system without generating a radio wave insensitive area.

It is a figure which shows the structural example of the center installation which manages the cover area of a some radio base station which comprises the mobile communication system by one Embodiment of this invention, and a radio base station. It is a figure which shows the example with each function with which the WiMAX center equipment and LTE center equipment shown in FIG. 1 are provided, and the table on the database which those functions refer and store. It is an example of the sequence chart explaining the operation | movement outline | summary of the function processing in the whole mobile communication system by embodiment of this invention. FIG. 4 is an example of a sequence chart for explaining details of a related sequence as a preliminary preparation for the determination control function in the sequence 300 of FIG. 3 to function. It is an example of a sequence chart explaining the detail of the related sequence of the base station operation status collection function in the sequence 200 of FIG. It is an example of a sequence chart explaining the detail of the related sequence of the call connection information collection / ratioing function in the sequence 301 of FIG. FIG. 4 is an example of a sequence chart for explaining details of a related sequence of a threshold determination / station identification function in a sequence 302 of FIG. 3. It is an example of the sequence chart explaining the detail of the related sequence of the adjacent condition determination function in the sequence 303 of FIG. FIG. 4 is an example of a sequence chart for explaining details of a sequence related to a power control function in a sequence 304 in FIG. 3. It is a figure which shows the structural example of a threshold value table. It is a figure which shows the structural example of a base station information table. It is a figure which shows the structural example of a connection call number data table. It is a figure which shows the structural example of a ratio data table. It is a figure which shows the structural example of a target station table. It is a figure which shows the structural example of an adjacent condition determination result table.

  Embodiments of a mobile communication system and a wireless base station power saving control method according to the present invention will be described below in detail with reference to the drawings.

  FIG. 1 is a diagram showing a cover area of a plurality of radio base stations constituting a mobile communication system according to an embodiment of the present invention and a configuration example of center equipment for managing the radio base stations.

  A mobile communication system according to an embodiment of the present invention includes a plurality of LTE radio base stations (hereinafter, the radio base stations are simply referred to as base stations) 21-1 to 21-3, and a coverage area 3-of those LTE base stations. 1 to 3-3 and a WiMAX base station 11-1 that is arranged outside the boundary of the cover areas 3-1 to 3-3 and serves in the cover area 3-4, and a WiMAX base station 11 includes a WiMAX center facility 1 that manages 11-1 and an LTE center facility 2 that manages a plurality of LTE base stations 21-1 to 21-3.

  The WiMAX center facility 1 also manages WiMAX base stations 11-2 to 11-n (not shown), and includes a call connection information collection / ratioing function 131, a threshold determination / station identification function 132, and an adjacent station status determination function 133. The determination control function 13 having the power control function 134, the database 12, and the input device 14 for inputting base station data to the database 12 are configured. The LTE center facility 2 collects data on whether or not the LTE base stations 21-1 to 21-n (only the LTE base stations 21-1 to 21-3 are shown in FIG. 1) are in operation. An operation status collection function 22 is provided.

  The WiMAX center facility 1 and the LTE center facility 2 described above are configured in an information processing apparatus including a storage device such as a CPU and an HDD, an input device such as a memory and a keyboard, a display device, a communication interface, etc. Each function described above is constructed by loading a program for performing processing in the embodiment of the present invention stored in a storage device into a memory and causing the CPU to execute the program.

  The call connection information collection / ratioing function 131, the threshold determination / station identification function 132, and the adjacent station status determination function that constitute the determination control function 13 for the WiMAX center facility 1 to control the transmission power of the WiMAX base station. 133 and the power control function 134 use data necessary for processing stored in the database 12. In addition, since data necessary as a precondition for these functional processes is stored in the database 12 in advance, the input device 14 used by the administrator is used.

  The transmission coverage areas 3-1 to 3-3 of the plurality of LTE base stations 21-1 to 21-3 exist so as to straddle each other. The WiMAX base station 11-1 is installed at the intermediate point, and the transmission coverage area 3-4 of the WiMAX base station 11-1 is covered by the transmission of the LTE base stations 21-1 to 21-3. It exists across the areas 3-1 to 3-3. The WiMAX base station 11-1 and one of the LTE base stations 21-1 to 21-n can be connected to each other, and both base stations can cooperate to provide services to the subscriber terminal.

  In the embodiment of the present invention, transmission is performed according to the number of connected calls to the WiMAX base station 11-1 surrounded by the LTE macro cell as described above and located outside the boundary of the macro cell. It controls the strength of power. Although only one WiMAX base station 11-1 is shown in FIG. 1, the WiMAX base stations to be controlled in the embodiment of the present invention are all of the plurality of WiMAX base stations in operation, and the transmission power The WiMAX base station that requires this control is specified by the determination control function 13 in the WiMAX center facility 1. The determination control function 13 performs control processing for all of the WiMAX base stations 11-1 to 11-n.

  In the above-described case, the transmission area of the WiMAX base station 11-1 is reduced by reducing the transmission power of the WiMAX base station 11-1, but the determination is made based on the minimum threshold of the transmission power of the WiMAX base station 11-1 held in advance. Thus, by operating the WiMAX base station 11-1 while reducing the transmission power within a range that does not fall below the minimum value of the transmission power, the WiMAX base station 11-1 can save power without generating a radio insensitive area. be able to. The minimum value of the transmission power is a value of the transmission power that does not cause an insensitive area with an adjacent station, which is determined by performing radio wave measurement or the like at the time of designing the placement of the base station. In the example shown in FIG. 1, the transmission coverage area 3-4 of the WiMAX base station 11-1 is changed to the transmission coverage areas 3-1 to 3-3 of the LTE base stations 21-1 to 21-3. It is a value of transmission power that will be the minimum cover area that straddles.

  FIG. 2 is a diagram showing an example of each function provided in the WiMAX center facility 1 and the LTE center facility 2 shown in FIG. 1 and a table on a database that is referenced and stored by each function.

  The base station operation status collection function 22 in the LTE center facility 2 collects data indicating whether or not all the LTE base stations 21-1 to 21-n monitored by the LTE center facility 2 are operating at a cycle of 5 minutes. The base station operation status collection function 22 then collects the collected LTE base station operation data to the LTE center facility 2 for 5 minutes in order to transmit and store the data in the database 12 in the WiMAX center facility 1. Access in cycles.

  The WiMAX center facility 1 includes the input device 14 as described above in order to store operational base station data, which is data necessary as a precondition for functional processing, in the database 12 in advance.

  The WiMAX center facility 1 includes a database 12, and the database 12 includes a threshold table 121, a base station information table 122, a connected call number data table 123, a ratio data table 124, a target station data table 125, an adjacent station as data tables. A situation determination result table 126 is held, and the database 12 exchanges data with each of the above-described functions constituting the determination control function 13.

  Next, prior to describing the operation of the control processing in the embodiment of the present invention, the configuration of each table described above held in the database will be described with reference to the drawings.

  FIG. 10 is a diagram illustrating a configuration example of the threshold value table 121. The threshold table 121 is a table for managing the management items of the plurality of WiMAX base stations 11-1 to 11-n under the management of the WiMAX center facility 1. The management items are WiMAX base station ID, transmission power normal value, transmission power lower limit threshold value, call number upper limit threshold value, and control call number ratio threshold value.

  In the above description, the WiMAX base station ID is a unique identifier that identifies the WiMAX base station. The transmission power normal value is a transmission power value during normal operation of the WiMAX base station, and is an upper limit threshold of transmission power in the embodiment of the present invention. The transmission power lower limit threshold is a minimum value of transmission power unique to the WiMAX base station. Even if the transmission power of the WiMAX base station is lowered, this value is the minimum that the adjacent LTE base station cover area can supplement the coverage area of the WiMAX base station, and no dead area is generated in the coverage area of the corresponding WiMAX base station. Value. The upper limit threshold for the number of calls is the maximum value of the number of calls that can be connected at a certain moment for each WiMAX base station. The control call number ratio threshold is a threshold for the number of calls to be controlled for each WiMAX base station. As these values, values determined at the time of station setting when the WiMAX base station is installed are used and set in advance as described later.

  FIG. 11 is a diagram illustrating a configuration example of the base station information table 122. This base station information table 122 manages the operation equivalent number of a plurality of WiMAX base stations 11-1 to 11-n under the management of the WiMAX center facility 1 in a column, and manages the management items of the WiMAX base station in a row. It is a table to do. The management items are WiMAX base station ID, LTE adjacent station 1 ID, LTE adjacent station 1 operating status, LTE adjacent station 2 ID, LTE adjacent station 2 operating status, and the LTE base station adjacent to the column of the WiMAX base station ID in the column. As many LTE base stations as the number of base stations, in some cases, for the base stations extending to five or six, the IDs of LTE adjacent stations and the operation status thereof are managed in rows. The operation status value “0” described above indicates that the operation is not performed, and the value “1” indicates that the operation is in progress.

  FIG. 12 is a diagram showing a configuration example of the connected call number data table 123. This connection call number data table 123 manages the operation equivalent number of a plurality of WiMAX base stations 11-1 to 11-n under the management of the WiMAX center facility 1 in a column and connects in a row every collection period of 5 minutes. Manage the number of calls (regardless of whether the connection continues at that time).

  FIG. 13 is a diagram illustrating a configuration example of the ratio data table 124. This ratio data table 124 manages the number of operation equivalents of the plurality of WiMAX base stations 11-1 to 11-n under the management of the WiMAX center facility 1 in the column, and each WiMAX base station in the collection period every 5 minutes in the row. Is managed as a ratio of the number of connected calls to the number of connectable calls.

  FIG. 14 is a diagram illustrating a configuration example of the target station table 125. This target station table 125 manages the number of operation equivalents of the plurality of WiMAX base stations 11-1 to 11-n under the management of the WiMAX center facility 1 in the column, and controls the transmission power every 5 minutes in the collection period in the row. The transmission power control target flag indicating whether or not to perform is managed. The value “0” of the transmission power control target flag means that no control is performed, the value “1” means that the transmission power is controlled to the lower limit value, and the value “2” means that the transmission power is controlled to the upper limit value. To do.

  FIG. 15 is a diagram illustrating a configuration example of the adjacent situation determination result table 126. This adjacency status determination result table 126 manages the operation equivalent number of the plurality of WiMAX base stations 11-1 to 11-n under the management of the WiMAX center facility 1 in the column, and adjoins the LTE in the collection cycle every 5 minutes. A control flag indicating whether or not the base station is operating is managed. The value “0” of the control flag means that it is not in operation, and the value “1” means that it is in operation.

  FIG. 3 is an example of a sequence chart for explaining an outline of the operation of the function processing in the entire mobile communication system according to the embodiment of the present invention. Next, this will be described.

(1) First, a related sequence is executed as a preliminary preparation for the determination control function 13 to function. This sequence is a process in which the operator of the WiMAX center facility 1 inputs data necessary for the determination control function 13 to function using the input device 14. The data stored in this sequence is necessary for execution of functional processing described later. Initial data storage is performed when the mobile communication system is constructed, and data update is performed in the WiMAX base station, LTE. Performed when adding base stations. Details of this processing will be described later with reference to FIG. 4 (sequence 300).

(2) Next, a related sequence of the base station operation status collection function 22 is executed. This sequence is a process in which the base station operation status collection function 22 collects operation presence / absence data from a plurality of LTE base stations including the LTE base station 21-1 and stores it in the base station information table 122 of the database 12. . Details of this processing will be described later with reference to FIG. 5 (sequence 200).

(3) Next, a related sequence of the call connection information collection / ratioing function 131 is executed. In this sequence, the call connection information collection / ratioing function 131 in the determination control function 13 in the WiMAX center facility 1 collects connection call number data from a plurality of WiMAX base stations including the WiMAX base station 11-1. This is processing to be stored in the connected call number data table 123 described with reference to FIG. 12 and the ratio data table 124 described with reference to FIG. Details of this processing will be described later with reference to FIG. 6 (sequence 301).

(4) Next, a related sequence of the threshold determination / station identification function 132 is executed. In this sequence, the threshold determination / station identification function 132 in the determination control function 13 in the WiMAX center facility 1 is the data in the threshold table 121 described in FIG. 10 in the database 12 and the data in the ratio data table 124 described in FIG. Referring to FIG. 14, the transmission power control target flag indicating whether or not to control the transmission power of the WiMAX base station is set in the target station table 125 described with reference to FIG. Details of this processing will be described later with reference to FIG. 7 (sequence 302).

(5) Next, the related sequence of the adjacent situation determination function 133 is executed. In this sequence, the adjacent state determination function 133 in the determination control function 13 in the WiMAX center facility 1 performs the data in the base station information table 122 described in FIG. 11 in the database 12 and the data in the target station table 125 described in FIG. Referring to FIG. 15, the adjacent state determination result table 126 described with reference to FIG. Details of this processing will be described later with reference to FIG. 8 (sequence 303).

(6) Next, a related sequence of the power control function 134 is executed. In this sequence, the power control function 134 in the determination control function 13 in the WiMAX center facility 1 refers to the adjacent condition determination result table 126 shown in FIG. 15 in the database 12 and the threshold value table shown in FIG. , A process for controlling the transmission power of the WiMAX base station. Details of this processing will be described later with reference to FIG. 9 (sequence 304).

  FIG. 4 is an example of a sequence chart for explaining the details of a related sequence as a pre-preparation for the determination control function 13 in the sequence 300 of FIG. 3 to function. Next, this will be described.

(1) The operator of the WiMAX center facility 1 uses the input device 14 to input data to all items in the threshold table 121 in the database 12 (sequence 401).

(2) Next, the operator of the WiMAX center facility 1 uses the input device 14 to input data to the corresponding management item in the base station information table 122 in the database 12 (sequence 402).

  In the sequence 300 shown in FIG. 4, the WiMAX base station ID of the base station information table 122 described with reference to FIG. 11 and the ID of the LTE base station adjacent to the WiMAX base station ID are set as LTE adjacent station 1 ID, LTE adjacent station 2 ID, LTE adjacent station ID 3, After that, a considerable number of LTE adjacent station ID data are input. The WiMAX base station ID of the base station information table 122 shown in FIG. 11 inputted in this sequence is the connected call number data table 123 shown in FIG. 12, the ratio data table 124 shown in FIG. Data consistency is maintained so that it is the same as the WiMAX base station ID, which is the management item of the target station data table 125 and the adjacent situation determination result table 126 shown in FIG. Note that a method for maintaining this consistency will be described in the process of each function described later.

  FIG. 5 is an example of a sequence chart for explaining details of a related sequence of the base station operation status collection function 22 in the sequence 200 of FIG. 3, and this will be described next.

(1) The base station operation status collection function 22 requests the LTE base station 21-1 for data for identifying the presence / absence of operation, and the LTE base station 21-1 responds as a response from the LTE base station 21-1. Data indicating the presence or absence of operation is received (sequences 411 and 412).
(2) The base station operation status collection function 22 collects data for identifying whether or not the LTE base station 21-1 is in operation as described above, transmits the data to the WiMAX center facility 1, and stores the data in the database 12. The corresponding data is stored in the base station information table 122 (sequence 413).

  The collection period for collecting the data for identifying whether or not the LTE base station 21-1 is in operation in the above-described process is a period that can maintain the real-time operation, such as a 5-minute period. Further, in the description of FIG. 5, the data is described as being collected from the LTE base station 21-1, but this process is sequentially executed for all operable LTE base station equivalents under the management of the LTE center facility 2. Is done.

  FIG. 6 is an example of a sequence chart for explaining details of a related sequence of the call connection information collection / ratioing function 131 in the sequence 301 of FIG. 3, and this will be described next.

(1) The call connection information collection / ratioing function 131 requests connection call count data from the WiMAX base station 11-1, and the connection of the WiMAX base station 11-1 as a response from the WiMAX base station 11-1. Receive call count data. The connected call number data represents the total number of connected calls of the WiMAX base station in 5 minutes (sequences 421 and 422).

(2) The call connection information collection / ratioing function 131 collects the connected call number data of the WiMAX base station 11-1 as described above and shows it in the database 12 in the WiMAX center facility 1 as shown in FIG. The corresponding data is stored in the connected call number data table 123 described above (sequence 423).

(3) Next, the call connection information collection / ratioing function 131 displays the number of connected calls in the latest time zone 5 minutes in the corresponding WiMAX base station ID in the connected call number data table 123 described with reference to FIG. The number of connected calls obtained is obtained by using the number of calls upper limit threshold value that is the maximum value of the number of calls that can be connected at a certain moment for each station defined in the threshold value table 121 described with reference to FIG. Refer to, acquire, and divide by the obtained call number upper limit threshold to calculate the ratio (sequence 424, 425).

(4) Thereafter, the call connection information collection / ratioing function 131 uses the calculated ratio in the ratio data table 124 described with reference to FIG. 13 and the ratio data for the latest WiMAX base station ID in the latest time zone of 5 minutes. (Sequence 426).

  In the description of FIG. 6 described above, the data is described as being collected from the WiMAX base station 11-1, but this process is performed sequentially for the number of WiMAX base station equivalents operated under the control of the WiMAX center facility 1. Executed.

  Also, the data stored in the connected call number data table 123 shown in FIG. 12 is stored as the number of connected calls every 5 minutes of the collection period of the corresponding WiMAX base station ID.

  FIG. 7 is an example of a sequence chart for explaining details of a related sequence of the threshold value determination / station identification function 132 in the sequence 302 of FIG. 3, and this will be described next.

(1) The threshold determination / station identification function 132 refers to the value of the control call number ratio threshold, which is the threshold of the number of calls to be controlled for each WiMAX base station, defined in the threshold table 121 described with reference to FIG. The call connection information collection / ratioing function 131, which is a preceding function, is calculated, and the ratio of the latest time zone for each WiMAX base station ID in the ratio data table 124 shown in FIG. Are acquired (sequences 431 and 432).

(2) Next, the threshold determination / station identification function 132 determines that the latest ratio of 5 minutes for each WiMAX base station ID in the ratio data table 124 shown in FIG. 13 is the WiMAX base in the threshold table 121 shown in FIG. If it is less than the control call number ratio threshold for each station ID, the control flag “1” is set to the WiMAX base in the target station table 125 described with reference to FIG. 14 in order to reduce the transmission power of the corresponding WiMAX base station to the minimum value. It is set as a value for the latest time zone of 5 minutes for each station ID. Further, the threshold determination / station identification function 132 is configured so that the latest ratio of 5 minutes for each WiMAX base station ID in the ratio data table 124 shown in FIG. 13 is different for each WiMAX base station ID in the threshold table 121 shown in FIG. If it is equal to or greater than the control call number ratio threshold, control flag 2 is set to increase the transmission power to the maximum value (sequence 433).

  FIG. 8 is an example of a sequence chart for explaining the details of the related sequence of the adjacency situation determination function 133 in the sequence 303 of FIG. 3, which will be described next.

(1) The adjacency status determination function 133 includes the LTE adjacent station 1 operating status, the LTE adjacent station 2 operating status, the LTE adjacent station 3 operating status for each WiMAX base station ID in the base station information table 122 illustrated in FIG. Further, reference is made to the operation status data of the LTE neighboring stations thereafter and the control target flag for the latest time zone of 5 minutes for each WiMAX base station ID in the target station table 125 shown in FIG. 14 and described. (Sequences 441 and 442).

(2) Then, the adjacency situation determination function 133 refers to the target station table 125 shown in FIG. 14, and for the WiMAX base station in which “1” indicating that the control target flag is an explanation target is set in FIG. 15 is set in the operation flag of the LTE neighboring station in the base station information table 122 shown in FIG. 15, the WiMAX base station in the neighboring situation determination result table 126 shown in FIG. 15 is set. For the latest time zone for each ID, the operation determination flag of the adjacent station is set to “1” indicating that it is in operation (sequence 443).

  FIG. 9 is an example of a sequence chart for explaining the details of a related sequence of the power control function 134 in the sequence 304 of FIG. 3, and this will be described next. A sequence 304-1 illustrated in FIG. 9 is a related sequence of the transmission power lower limit control performed by the power control function 134, and a related sequence 304-2 is a related sequence of the transmission power upper limit control performed by the power control function 134.

(1) The power control function 134 sets the control target flag for the latest time zone 5 minutes for each WiMAX base station ID in the target station table 125 shown in FIG. The target station for which “1” is set is searched (sequence 451).

(2) Next, the control target flag for the latest time zone of 5 minutes for each WiMAX base station ID in the adjacent status determination table 126 shown in FIG. Search for stations for which "1" is set (sequence 452).

(3) Next, the power control function 134 refers to the transmission power lower limit value of the threshold value table 121 shown in FIG. 10 for the station searched in the process of sequence 452, and sets the value to the WiMAX base station 11- 1 is set so that the transmission power of the WiMAX base station 11-1 becomes the lower limit value (sequences 453 and 454).

(4) Alternatively, the power control function 134 sets the control target flag for the latest time zone 5 minutes for each WiMAX base station ID in the target station table 125 shown in FIG. 14 as the related sequence 304-2 of the transmission power upper limit control. A target station for which “2” is set in is searched (sequence 461).

(5) Next, the power control function 134 refers to the transmission power normal value of the threshold table 121 shown in FIG. 10 for the target station searched in the process of the sequence 461, and sets the value to the WiMAX base station 11 Is set so that the transmission power of the WiMAX base station 11-1 becomes the upper limit value (sequences 462 and 463).

  Next, an example will be specifically described on the assumption that the transmission power of the WiMAX base station having the WiMAX base station ID 10001 in the tables 121 to 126 shown in FIGS. 10 to 15 is controlled.

  The transmission power normal value of the corresponding WiMAX base station in the threshold table 121 shown in FIG. 10 is 40.0 dBm, the transmission power lower limit threshold is 37.0 dBm, and the call number upper limit threshold that is the maximum number of connectable calls for each station is 20. The control call number ratio threshold which is the threshold of the number of calls to be controlled for each station is 0.1. Further, as the LTE adjacent station of the WIMAX base station ID 10001 in the base station information table 122 shown in FIG. 11, the LTE adjacent station 1ID is a, the LTE adjacent station 2ID is b, and there are two LTE adjacent stations. Since “1” is set in the flags of the LTE adjacent station 1 operating status and the LTE adjacent station 2 operating status, both LTE adjacent stations are in the operating state. When the flag “0” is not set, it means that the LTE adjacent station is in an operation stop state.

  Referring to FIG. 6, as shown in the sequences 424 to 426, the call connection information collection / ratioing function 131 performs the latest time zone of the corresponding WiMAX base station ID in the connected call number data table 123 shown in FIG. 12. The number of connected calls “1”, which is data of 0:05 to 0:10, is obtained, and the ratio 0.05 is calculated by dividing this value by the call number upper limit threshold “20” of the threshold table 121 shown in FIG. Then, the value of the ratio 0.05 is stored in the corresponding time portion of the ratio data table 124 shown in FIG.

  Also, referring to FIG. 7, the threshold determination / station identification function 132, as shown in its sequence 431 to 433, shows the latest time zone 0:05 to the relevant WiMAX base station ID in the ratio data table 124 shown in FIG. In order to determine that the 0:10 ratio 0.05 is less than the control number ratio threshold value 0.1 of the corresponding WiMAX base station in the threshold table 121 shown in FIG. The control flag “1” is set at the corresponding time point of the corresponding station in the target station table 125 shown in FIG.

  Next, referring to FIG. 8, as shown in the sequences 441 to 443, the adjacent station status determination function 133 performs the LTE adjacent station 1 operation status for each WiMAX base station ID in the base station information table 122 shown in FIG. 11. Refer to the data of the LTE adjacent station 2 operating status and the LTE adjacent station 3 operating status, and refer to the control target flag for the latest time zone 5 minutes for each WiMAX base station ID in the target station table 125 shown in FIG. After confirming that the flag of the relevant time point of the relevant WiMAX base station is “1”, whether or not the adjacent station at the relevant time point of the relevant WiMAX base station in the adjacent state determination result table 126 shown in FIG. Set “1” to the determination flag.

  Next, referring to FIG. 9, as shown in the sequences 452 and 453, the power control function 134 sets the flag “1” at the corresponding time position of the corresponding WiMAX base station in the adjacent situation determination result table 126 shown in FIG. ”Is set, and the transmission power lower limit threshold value 37.0 dBm in the threshold table 121 shown in FIG. 10 is set as the transmission power parameter in the WiMAX base station of the WiMAX base station ID 10001, so that the WiMAX base station Control transmission power.

  According to the above-described embodiment of the present invention, the radio base station is controlled according to the call connection amount of the WiMAX base station, which is the radio base station to be controlled, at a certain time interval, that is, the usage rate of the radio base station by the user. Since the transmission power required for the station can be controlled, the power saving of the entire mobile communication system can be achieved. Further, according to the embodiment of the present invention, the strength of transmission power can be controlled without stopping the operation of the WiMAX base station itself, so that the WiMAX base station can be saved without generating an insensitive area of radio waves. Electricity can be achieved. Furthermore, according to the embodiment of the present invention, even when the number of terminals that make connection requests increases rapidly in the WiMAX base station area, it becomes possible to respond to those connection requests.

  The embodiment of the present invention described above has been described as controlling the power consumption of the WiMAX base station by controlling the transmission power of the WiMAX base station in real time (every 5 minutes), but the present invention is described above. It is also possible to control the transmission power of the WiMAX base station by performing prediction based on the data accumulated in each table in the processing of the embodiment of the present invention. In the above-described embodiment of the present invention, the transmission power value used for the control is described as two values of the transmission power lower limit threshold value and the transmission power normal value (upper limit value). However, the present invention is used for the control. It is also possible to set three or more transmission power values to be controlled and control with a transmission power value suitable for the call connection amount.

  Further, the embodiment of the present invention described above is installed in a place surrounded by a plurality of LTE base stations and a plurality of macro cells by the plurality of LTE base stations and out of the boundary of the macro cells. The WiMAX base station in the mobile communication system configured with a plurality of WiMAX base stations has been described as controlling the strength of transmission power according to the number of connected calls, but the present invention relates to an LTE base station, WiMAX. The present invention can also be applied when the base station is a radio base station of another communication method. That is, the present invention is surrounded by a plurality of radio base stations having an arbitrary communication method and a plurality of cover areas by the plurality of radio base stations, and deviates from the boundaries of the cover areas. The present invention can also be applied to control of transmission power for a radio base station having another communication method in a mobile communication system configured with a radio base station of another communication method installed in a place.

DESCRIPTION OF SYMBOLS 1 WiMAX center equipment 11-1 to 11-n WiMAX base station 12 Database 121 Threshold table 122 Base station information table 123 Connection call number data table 124 Ratio data table 125 Target station table 126 Adjacent situation determination result table 13 Judgment control function 131 Call Connection information collection / ratioing function 132 Threshold determination / station identification function 133 Adjacent station status determination function 134 Power control function 2 LTE center equipment 21-1 to 21-n LTE base station 22 Base station operation status collection function 14 Input device

Claims (4)

In a mobile communication system in which a plurality of radio base stations having first and second communication methods are distributed in one area to provide services to subscriber terminals,
Surrounded by a plurality of radio base stations having the first communication method and a plurality of cover areas by the plurality of radio base stations and installed at a place outside the boundary of the cover areas A radio base station having a second communication method, a first center facility for managing a plurality of radio base stations having the first communication method, and a plurality of radio base stations having the second communication method. A second center facility to manage,
The first center facility collects information on the presence / absence of operation as information on the operation status of each of the plurality of radio base stations having the first communication method, transmits the information to the second center facility, and transmits the second center facility. Base station operation status collection means for storing in a database provided in the center equipment of
The second center facility collects connection call number data of each of a plurality of radio base stations having the second communication method, and a plurality of radio base stations having the collected connection call number and the second communication method Call connection information collection / ratioing means for calculating a ratio with a predetermined call number upper limit threshold for each, a plurality of radio base stations having the calculated ratio and the second communication method. Threshold value for determining whether to reduce or increase the transmission power of each of the plurality of radio base stations having the second communication method by comparing a control call number ratio threshold value that is a ratio of the number of connected calls and a call number upper limit threshold value Each of the plurality of radio base stations having the second communication scheme is determined based on the determination / station identification means and information on the presence / absence of operation of each of the plurality of radio base stations having the first communication scheme stored in the database. Adjacent the first communication method Whether to reduce or increase the transmission power of each of the plurality of radio base stations having the second communication method and the adjacent station status determination means for determining whether or not each of the plurality of radio base stations is operating The transmission power of each of the plurality of radio base stations having the second communication scheme is determined in advance with reference to the information and information on the presence / absence of operation of each of the plurality of radio base stations having the adjacent first communication scheme. And a power control means for controlling the power to reach a lower limit value or an upper limit value. It said plurality of radio base stations with a first communication method is LTE radio base station, the mobile communication according to claim 1, wherein the radio base station having the second communication system is a WiMAX base station system. Predetermined lower limit, the mobile communication system according to claim 1, characterized in that the minimum transmission power value without causing a dead spot of the radio wave of the transmission power. In a power saving control method for a radio base station in a mobile communication system in which a plurality of radio base stations having the first and second communication schemes are distributed in one area to provide services to subscriber terminals
The mobile communication system is surrounded by a plurality of radio base stations having a first communication scheme and a plurality of cover areas by the plurality of radio base stations, and deviates from the boundaries of the cover areas. A wireless base station having a second communication method installed in a location, a first center facility for managing a plurality of wireless base stations having the first communication method, and having the second communication method A second center facility for managing a plurality of radio base stations,
The first center facility collects information on the presence / absence of operation as information on the operation status of each of the plurality of radio base stations having the first communication method, transmits the information to the second center facility, and transmits the second center facility. Stored in the database provided in the center equipment,
The second center facility collects connection call number data of each of a plurality of radio base stations having the second communication method, and a plurality of radio base stations having the collected connection call number and the second communication method A ratio with a predetermined call number upper limit threshold is calculated for each, and the calculated ratio and the number of connected calls and call upper limit threshold predetermined for each of a plurality of radio base stations having the second communication method, Is compared with the control call number ratio threshold value, which is a ratio of the first communication number, to determine whether to lower or increase the transmission power of each of the plurality of radio base stations having the second communication method, and to store the first stored in the database Each of the plurality of radio base stations having the first communication scheme adjacent to each of the plurality of radio base stations having the second communication scheme based on information on the presence / absence of operation of each of the plurality of radio base stations having the communication scheme of To determine whether or not Information on whether to reduce or increase the transmission power of each of the determined plurality of radio base stations having the second communication method and whether or not each of the adjacent plurality of radio base stations having the first communication method is operated The power saving of the radio base station, wherein the transmission power of each of the plurality of radio base stations having the second communication scheme is controlled to be a predetermined lower limit value or upper limit value with reference to the information of Control method.

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