JP2015177274A - Device and method for calculation of base station parameter, and control program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a calculation amount at the calculation of a base station parameter, and to reduce the calculation time of an optimal base station parameter.SOLUTION: A storage unit of a base station parameter calculation device stores a plurality of radio wave environment maps, which represent radio wave environments in a local network area and are generated in advance, on the basis of communication parameters which a plurality of base stations, disposed in the local network area in a distributed manner, collect when performing radio communication with communication terminals. A calculation processing unit performs the processing of: estimating communication parameters of a plurality of virtual communication terminals, virtually disposed in a local network area, to a set base station parameter, on the basis of the plurality of radio wave environment maps, to evaluate the base station parameter and calculate each new base station parameter for the plurality of base stations, on the basis of the evaluation result; and repeating the above processing to the calculated base station parameter, until a predetermined calculation completion condition is satisfied.

Description

  Embodiments described herein relate generally to a base station parameter calculation device, a base station parameter calculation method, and a control program.

  While mobile traffic is increasing year by year and further speeding up of mobile communication is demanded, each communication carrier has started LTE (Long Term Evolution) service, which is high-speed wireless communication. On the other hand, mobile traffic has been increasing year by year, and the wireless data quality of indoor traffic has been improved due to further growth of mobile data traffic.

  In order to improve indoor traffic capacity, it is necessary to arrange a large number of base stations called femtocells having a radio wave radius of several tens of meters at a short distance. When operating a plurality of small base stations indoors, the combination of parameters such as transmission power and frequency allocated to each base station increases in proportion to the exponential function of the number of base stations. Further, the combination of parameters such as transmission power and frequency allocated to each base station increases exponentially with the number of base stations.

JP 2004-274313 A

Therefore, when searching all combinations of base station parameters, there is a problem that the calculation time of the optimum parameters becomes enormous.
Therefore, an object of the present invention is to reduce a calculation amount when calculating a base station parameter and reduce a calculation time of an optimal base station parameter, a base station parameter calculation method, and a control method for the base station parameter To provide a program.

The storage unit of the base station parameter calculation apparatus according to the embodiment includes a local network created in advance based on communication parameters collected when a plurality of base stations distributed in the local network area perform wireless communication with communication terminals. A plurality of radio wave environment maps representing the radio wave environment in the area are stored.
The calculation processing unit estimates the communication parameters of a plurality of virtual communication terminals virtually arranged in the local network area with respect to the set base station parameter based on the plurality of radio wave environment maps, and evaluates the base station parameter. The process of calculating new base station parameters for a plurality of base stations based on the evaluation result is repeated until the predetermined calculation end condition is satisfied for the calculated base station parameters.

FIG. 1 is a schematic configuration block diagram of a wireless communication system according to an embodiment. FIG. 2 is a functional configuration block diagram of the control device, the base station, and the communication terminal. FIG. 3 is an explanatory diagram of a chromosome model used in the present embodiment. FIG. 4 is an explanatory diagram of a base station parameter calculation process using a genetic algorithm. FIG. 5 is an explanatory diagram (part 1) of the relationship between the generated minimum SINR and fitness for each chromosome. FIG. 6 is an explanatory diagram (part 2) of the relationship between the generated minimum SINR and the fitness for each chromosome. FIG. 7 is an explanatory diagram (part 1) of the relationship between the combination of the minimum SINR and the average SINR for each generated chromosome and the fitness. FIG. 8 is an explanatory diagram (part 2) of the relationship between the combination of the minimum SINR and the average SINR for each generated chromosome and the fitness. FIG. 9 is an explanatory diagram (part 3) of the relationship between the combination of the minimum SINR and the average SINR for each generated chromosome and the fitness. FIG. 10 is a communication sequence flowchart of the main communication operation of the embodiment.

  Hereinafter, embodiments will be described with reference to the drawings.

FIG. 1 is a schematic configuration block diagram of a wireless communication system according to an embodiment.
The wireless communication system 100 includes a control device 10 that controls the wireless communication system 100 in an integrated manner, a plurality of base stations 20-1 to 20-3 connected to the control device 10 via a local network 11, and a local network 11. And a plurality of communication terminals that are accommodated in the base station 20-1 and perform wireless communication within the wireless communication area of the base station 20-1 and the core network (operator network) 13 connected via the gateway (server) 12 30-1 to 30-3.

FIG. 2 is a functional configuration block diagram of the control device, the base station, and the communication terminal.
In this case, since the base stations 20-1 to 20-3 and the corresponding communication terminals (30-1 to 30-3) have the same configuration, the base station 20-1 and the communication terminal 30 in FIG. -1 is shown as an example.

  The control device 10 aggregates terminal information of all communication terminals including the communication terminals 30-1 to 30-3 accommodated in all the base stations 20-1 to 20-3 under its management. Unit 101, base station control unit 102 that controls all base stations 20-1 to 20-3 under its management, and provisional optimum parameter update unit 103 that updates provisionally determined optimum base station parameters as needed. An fitness calculation unit 104 that calculates the fitness of the evaluation value of the set base station parameter, an fitness comparison unit 105 that compares a plurality of fitness values calculated by the fitness calculation unit 104, and fitness Fitness setting unit 106 for setting the number of searches, search number selection unit 107 for selecting the number of searches, radio wave environment analysis unit 108 for analyzing the radio wave environment, parameter calculation unit 109 for calculating base station parameters, and base station 20 -1 A parameter setting unit 110 for setting base station parameter calculated in 20-3, and a.

  In the above configuration, the terminal information includes received power information, physical cell ID corresponding to the base station to be communicated, connected base station information, GPS information (communication terminal location information), communication throughput (SINR: Signal to Interference and Noise power). Ratio), error rate during communication, terminal identification information, and the like.

Further, the control device 10 includes, for example, a MPU (Micro Processing Unit), a program storage area for MPUs such as a ROM (Read Only Memory) and a RAM (Random Access Memory), a data storage area, and the like. . The control device 10 causes the MPU to execute a program, thereby allowing the terminal information aggregation unit 101, the base station control unit 102, the provisional optimal parameter update unit 103, the fitness calculation unit 104, the fitness comparison unit 105, and the fitness setting unit 106. , Function as search number selection unit 107, radio wave environment analysis unit 108, parameter calculation unit 109, and parameter setting unit 110.
The radio wave environment analysis unit 108 also functions as a storage unit that stores a plurality of radio wave environment maps representing the radio wave environment.

  In the above configuration, the terminal information aggregating unit 101 aggregates terminal information transmitted from the base stations 20-1 to 20-3. The terminal information aggregating unit 101 outputs the aggregated terminal information to the radio wave environment analyzing unit 108. Note that the terminal information aggregating unit 101 makes a terminal information acquisition request to each of the base stations 20-1 to 20-3 even if the terminal information from the base stations 20-1 to 20-3 is periodically received. You may receive it.

The radio wave environment analysis unit 108 functions as a map creation unit that creates a radio wave environment map and a map accumulation unit that accumulates the radio wave environment map created by the map creation unit.
Here, when the radio wave environment analysis unit 108 functions as a map accumulation unit, a radio wave environment map and virtual communication created by the map creation unit from a past radio wave environment map accumulated according to a request from the map creation unit. Search for radio wave environment maps with similar terminal distributions.

Then, the map accumulation unit delivers the radio wave environment map extracted by the search to the map creation unit.
The map storage unit sets a higher priority for the radio wave environment map that is used more frequently than the radio wave environment map that is stored. For example, the map accumulating unit counts the number of times the radio wave environment map is delivered to the map creating unit for each radio wave environment map as an index for grasping the usage frequency, and sets a high priority for the radio wave environment map having a large number of times. .

On the other hand, the radio wave environment analysis unit 108 that functions as a map creation unit performs clustering on the terminal information transmitted from the terminal information aggregation unit 101 and combines the communication terminals that are determined to be close to each other as a virtual communication terminal. Extract.
Here, “being close to each other” means, for example, that the distance between communication terminals is located in a range closer than a predetermined distance. This virtual communication terminal includes terminal information aggregated when the communication terminals are collected. As a clustering method, even generally known hierarchical clustering such as a group average method, a single connection method, and a complete connection method, non-hierarchical clustering such as a K-means method and an EM (Expectation Maximization) algorithm can be used. There may be. For example, when hierarchical clustering is employed, the map creation unit determines that a communication terminal having similar terminal information is in the vicinity. The map creation unit creates a radio wave environment map indicating the distribution of virtual communication terminals in the indoor area. The map creation unit delivers the created radio wave environment map to the map storage unit.

In addition, when there is an area where a virtual communication terminal cannot be extracted because there is no communication terminal and terminal information cannot be acquired, the radio wave environment analysis unit 108 functioning as a map creation unit Supplement virtual communication terminals as appropriate.
At this time, the map creation unit makes a search request for the radio wave environment map to the map storage unit. The map creation unit acquires a radio wave environment map having a similar distribution of virtual communication terminals to the created radio wave environment map from the radio wave environment map stored in the map storage unit.
And a map preparation part complements the virtual communication terminal of the area where a virtual communication terminal is not extracted by the acquired electromagnetic wave environment map, and produces the complementary electromagnetic wave environment map containing the complemented virtual communication terminal. The map creation unit transmits the created complementary radio wave environment map to the parameter calculation unit 109.

  The radio wave environment analyzing unit 108 functioning as a map creating unit transmits sensor information such as GPS transmitted from the communication terminals (30-1 to 30-3) via the base stations (20-1 to 20-3). The position of each communication terminal (30-1 to 30-3) may be specified based on the above. At this time, the radio wave environment analysis unit 108 functioning as a map creation unit has the communication terminals (30-1 to 30-3) in the vicinity of each other based on the position information of the communication terminals (30-1 to 30-3). The communication terminals that are determined to be close to each other are collected and extracted as virtual communication terminals.

  The parameter calculation unit 109 calculates a transmission power, an operating frequency, a physical cell ID, a neighbor list including neighbor cell information, a handover threshold, a base station ID, and a frequency from the complementary radio wave environment map created as a map creation unit. Determine bandwidth, base station IP address, cell size, etc. The neighbor list and the handover threshold can be combined with the transmission power and the operating frequency to create a radio wave environment. In other words, for the neighbor list (including neighboring cell information), when the neighbor list (including neighboring cell information) is intentionally changed during operation, it is assumed that frequency resources will be reassigned to the communication terminal during operation. It is possible to control handover and create a radio wave environment. As for the handover threshold, if the changed handover threshold is used, the connection destination of the terminal can be changed to improve the throughput.

  The parameter setting unit 110 sets the base station parameters calculated by the parameter calculation unit 109 in the base stations 20-1 to 20-3.

  Here, as a specific example of the base station parameter, a method for determining the transmission power and operating frequency of the base station will be described.

In the present embodiment, the parameter calculation unit 109 calculates base station parameters using a genetic algorithm.
FIG. 3 is an explanatory diagram of a chromosome model used in the present embodiment.
FIG. 3 shows a chromosome model having six base stations.
The chromosome model 40 includes a set of transmission power genes and operating frequency genes for each base station.
In the case of the example in FIG. 3, three types of transmission power of 100 mW, 50 mW, and 10 mW are assumed, and the genes are 0, 1, and 2, respectively.
As operating frequencies, three types of frequency F1, frequency F2, and frequency F3 are assumed, and the genes are 0, 1, and 2, respectively.
That is, in the example of FIG. 3, it can be seen that the transmission power of the first base station BS1 is 50 mW and the operating frequency is the frequency F1.
Similarly, the transmission power of the second base station BS2 is 100 mW, the operation frequency is the frequency F2, the transmission power of the third base station BS3 is 50 mW, the operation frequency is the frequency F1, The transmission power of the base station BS4 is 100 mW, the operation frequency is the frequency F3, the transmission power of the fifth base station BS5 is 50 mW, the operation frequency is the frequency F1, and the transmission power of the sixth base station BS6. It can be seen that is 50 mW and the operating frequency is frequency F3.

Next, base station parameter calculation processing using a genetic algorithm will be described.
FIG. 4 is an explanatory diagram of a base station parameter calculation process using a genetic algorithm.
In FIG. 4, for simplicity of illustration, the case where the base stations are two base stations 20-1 and 20-2 is illustrated.

First, an initial chromosome model of the chromosome model is created.
Specifically, a predetermined number of individuals, that is, 4 (= 2 × 2) chromosomes corresponding to the two base stations 20-1 and 20-2 are randomly generated.

  That is, the parameter calculation unit 109 sets the operating frequency and transmission power for the base stations 20-1 and 20-2 in a simulated manner, receives the complementary radio wave environment map transmitted from the radio wave environment analysis unit 108, and receives the received radio wave environment map. SINR (communication throughput) is estimated for each virtual communication terminal from the terminal information corresponding to the virtual communication terminal in the supplementary radio wave environment map. Further, the parameter calculation unit 109 obtains the SINR variance, the lowest SINR (value), the average SINR (value), and the highest SINR (value) from the calculated SINR for each virtual communication terminal, and notifies the fitness calculation unit 104 of it.

  Thereby, the fitness calculation unit 104 calculates fitness based on the calculated SINR variance, minimum SINR (value), average SINR (value), and maximum SINR (value).

Here, a case where the fitness is calculated based on the minimum SINR will be described as a specific example.
FIG. 5 is an explanatory diagram (part 1) of the relationship between the generated minimum SINR and fitness for each chromosome.
In the example of FIG. 5, the higher the minimum SINR value is, the higher the fitness is, and the minimum SINR value is adopted as it is as it is.

  More specifically, the fitness calculation unit 104 sets the fitness = 10 when the chromosome = “0001”, and thus the fitness = 10. When the chromosome = “1111”, the fitness calculation unit 104 adapts because the minimum SINR = 7 dB. When degree = 7 and chromosome = “1101”, the minimum SINR = 6 dB, so fitness = 6.

FIG. 6 is an explanatory diagram (part 2) of the relationship between the generated minimum SINR and the fitness for each chromosome.
In the example of FIG. 6, the lowest SINR is compared with a threshold value, and a binary evaluation is adopted in which the fitness level is high when the minimum SINR is equal to or higher than the threshold level and the fitness level is low when the minimum SINR is less than the threshold level. doing.

  More specifically, the fitness calculation unit 104 sets the threshold value = 8 dB. When the chromosome = “0001”, the minimum SINR = 10 dB is equal to or higher than the threshold value, so the fitness = high, and the chromosome = “1111”. Since the minimum SINR = 7 dB and less than the threshold, the fitness is low, and when chromosome = “1101”, the minimum SINR = 6 dB is less than the threshold and the fitness is low.

  The reason why the binary evaluation is employed in this way is that an optimal gene does not always remain when the minimum SINR value is simply used as the fitness.

FIG. 7 is an explanatory diagram (part 1) of the relationship between the combination of the minimum SINR and the average SINR for each generated chromosome and the fitness.
In the case of the examples of FIGS. 5 and 6, the fitness is obtained only by the lowest SINR. However, FIG. 7 shows a case where the fitness is subjected to binary evaluation based on the combination of the lowest SINR and the average SINR.

  In the example of FIG. 7, fitness = high when the minimum SINR exceeds the minimum SINR threshold and the average SINR exceeds the average SINR threshold, and fitness = low for the other combinations.

FIG. 8 is an explanatory diagram (part 2) of the relationship between the combination of the minimum SINR and the average SINR for each generated chromosome and the fitness.
In the example of FIG. 8, the difference (error) value between the lowest SINR of the optimal solution having the highest value among all the calculated lowest SINRs and the lowest SINR for each chromosome and the calculated average SINRs. The fitness is binarized based on the difference (error) between the average SINR of the optimal solution having the highest value and the average SINR for each chromosome.

  That is, as shown in FIG. 8, the difference (error) between the minimum SINR of the optimal solution and the minimum SINR for each chromosome is a predetermined value α (> 0) dB or more, and the average SINR of the optimal solution and each chromosome When the value of the difference (error) from the average SINR is equal to or greater than the predetermined value α dB, the fitness = low.

  The difference (error) between the lowest SINR of the optimal solution and the minimum SINR for each chromosome is less than a predetermined value α dB, and the difference (error) between the average SINR of the optimal solution and the average SINR for each chromosome is predetermined. The fitness is also low when the value is equal to or greater than αdB.

  The difference (error) between the lowest SINR of the optimal solution and the minimum SINR for each chromosome is a predetermined value α dB or more, and the difference (error) between the average SINR of the optimal solution and the average SINR for each chromosome is predetermined. When the value is less than α dB, the fitness is low.

  On the other hand, the difference (error) between the lowest SINR of the optimal solution and the lowest SINR for each chromosome is less than a predetermined value α dB, and the difference (error) between the average SINR of the optimal solution and the average SINR for each chromosome is predetermined. When the value is less than α dB, the fitness is high.

FIG. 9 is an explanatory diagram (part 3) of the relationship between the combination of the minimum SINR and the average SINR for each generated chromosome and the fitness.
In the case of FIGS. 7 and 8 described above, binary evaluation is performed, but in FIG. 9, the fitness is evaluated in multiple stages (in the case of FIG. 9, four stages).

  That is, as shown in FIG. 9, the difference (error) between the minimum SINR of the optimal solution and the minimum SINR for each chromosome is a predetermined value α (> 0) dB or more, and the average SINR of the optimal solution and each chromosome When the value of the difference (error) from the average SINR is equal to or greater than the predetermined value α dB, the fitness = low.

  The difference (error) between the lowest SINR of the optimum solution and the lowest SINR for each chromosome is not less than the predetermined value β (0 <β <α) dB and less than the predetermined value α dB, and the average of the optimum solutions When the difference (error) between the SINR and the average SINR for each chromosome is equal to or greater than the predetermined value β dB and less than the predetermined value α dB, the fitness is medium-low (medium low).

  The difference (error) between the minimum SINR of the optimal solution and the minimum SINR for each chromosome is not less than the predetermined value γ (0 <γ <β) dB and less than the predetermined value β dB, and further, the average of the optimal solutions When the difference (error) between the SINR and the average SINR for each chromosome is not less than the predetermined value γdB and less than the predetermined value βdB, the fitness = medium / high (medium high).

  The difference (error) between the lowest SINR of the optimal solution and the lowest SINR for each chromosome is less than a predetermined value γdB, and the difference (error) between the average SINR of the optimal solution and the average SINR for each chromosome is predetermined. If it is less than the value γdB, the fitness = high.

The parameter calculation process will be described again.
Subsequently, the parameter calculation unit 109 dominates a gene (base station parameter: transmission power and frequency in the above example) that places importance on the minimum SINR (minimum communication throughput or minimum communication speed) based on the fitness described above. The gene (dominant base station parameter) is selected (remaining), and two chromosomes (= a combination of base station parameters corresponding to a plurality of base stations: parents) are selected from the selected priority genes, and crossover is performed.

Here, as a method of crossover, one-point crossover, multipoint crossover, uniform crossover, etc., which are common as genetic algorithms, are performed.
Furthermore, the fitness calculation unit 104 performs a mutation operation to change a value of a part of the chromosome (in this embodiment, transmission power or frequency) with a predetermined mutation probability after the crossover process, and obtains a chromosome ( = A combination of base station parameters corresponding to a plurality of base stations), and the fitness evaluation process described above is performed again.

  The parameter calculation unit 109 repeatedly performs the obtained chromosome, that is, a combination of base station parameters corresponding to the calculated plurality of base stations, until a predetermined calculation end condition is satisfied.

  Here, “predetermined condition for completion of calculation” generally means that a combination of the same base station parameters is repeatedly generated, or a combination of a plurality of base station parameters that can be considered technically similar is short. A state that is repeatedly generated in a cycle.

In this case, based on an empirical rule, the amount of calculation until the optimum solution according to changes in the radio wave environment, that is, the combination of base station parameters corresponding to a plurality of base stations for which a predetermined evaluation is obtained, is minimized. It is possible to change the number of generations, number of individuals, gene type, gene length, number of generations, crossover probability, crossover type, mutation probability, mutation method, parents selection type, etc. is there.
As a result, the base station parameter calculation time is further reduced.

Next, the configuration of the base station will be described again with reference to FIG.
The base station 20-1 includes a wireless communication unit 201, a terminal information aggregation unit 202, and a terminal information notification unit 203.

  The wireless communication unit 201 performs wireless communication with the communication terminals 30-1 to 30-3.

The terminal information aggregating unit 202 receives terminal information transmitted from the communication terminals 30-1 to 30-3, and aggregates the received terminal information together with identifiers.
Here, when requesting terminal information to the communication terminals 30-1 to 30-3, the terminal information aggregating unit 202 requests terminal information from all of the communication terminals 30-1 to 30-3. The terminal information may be requested only from the communication terminal that is in the connected state except for the idle state. Note that the idle state refers to a state in which the communication terminal stops the communication function when there is no communication between the base station and the communication terminal for a predetermined period.

  The terminal information notification unit 203 notifies (transmits) the aggregated terminal information to the control device 10. Note that the terminal information notification unit 203 may notify (transmit) the terminal information to the control device 10 at a preset timing.

Next, the configuration of the communication terminal will be described with reference to FIG.
The communication terminal 30-1 includes a wireless communication unit 301, a terminal information acquisition unit 302, a terminal information holding unit 303, and a terminal information notification unit 304.

  Based on the LTE protocol, the wireless communication unit 301 performs wireless communication with, for example, the base station (base station 20-1 in the example of FIG. 2) having the highest received power among the base stations 20-1 to 20-3. Do.

  The terminal information acquisition unit 302 includes received power of signals transmitted from the base stations 20-1 to 20-3, a physical cell ID that identifies the base station that transmitted the signal, SINR (communication throughput: communication speed), An error rate during communication and sensor information for specifying the position of a communication terminal such as GPS (Global Positioning System) are acquired at a preset cycle. The received power and physical cell ID can be acquired by LTE standard specifications.

  The terminal information holding unit 303 creates and holds a correspondence table for the acquired received power and physical cell ID as terminal information. The terminal information holding unit 303 updates the held terminal information (correspondence table) every time new reception power and physical cell ID are acquired by the terminal information acquisition unit 302.

  The terminal information notification unit 304 transmits the held terminal information and sensor information to the base station 20-1 as terminal information in response to a request from the connected base station 20-1. At this time, terminal information notifying section 304 attaches its own terminal identifier to the terminal information and transmits it to base station 20-1. Note that the terminal information notification unit 304 may actively transmit terminal information to the base station 20-1 at a preset timing.

Next, an outline operation of the embodiment will be described.
FIG. 10 is a communication sequence flowchart of the main communication operation of the embodiment.
In FIG. 3, the communication operation of the control device 10, the base station 20-1, and the communication terminals 30-1 to 30-3 will be described as an example.

  First, the communication terminals 30-1 to 30-3 transmit, as terminal information, a correspondence table for the received power and physical cell ID that is held to the base station 20-1 together with an identifier that can identify the own terminal ( Step S101).

The base station 20-1 receives terminal information transmitted from the communication terminals 30-1 to 30-3, and aggregates the received terminal information (step S102).
Then, the base station 20-1 notifies (transmits) the aggregated terminal information to the control device 10 (step S103). This notification to the control device 10 is performed periodically.

  As a result, the terminal information aggregating unit 101 of the control device 10 receives terminal information including at least reception power, physical cell ID, and terminal identification information transmitted from the base stations 20-1 to 20-3 via the local network 11. The received terminal information is collected and updated (step S104).

Then, the terminal information aggregating unit 101 notifies the radio wave environment analyzing unit 108 of the aggregated terminal information (step S105).
The radio wave environment analysis unit 108 analyzes the radio wave environment in the local network area where the base stations 20-1 to 20-3 are distributed and arranged based on the aggregated terminal information (step S106), and the radio wave environment analysis result Is notified to the parameter calculation unit 109 (step S107).

As a result, the parameter calculation unit 109 calculates the base station parameter by the method using the genetic algorithm described above (step S108).
Then, the parameter calculation unit 109 notifies the fitness calculation unit 104 of the calculated base station parameter (step S109).

Thereby, the fitness calculation unit 104 calculates the fitness (step S110), evaluates the fitness (step S111), and leaves a dominant gene based on the fitness (step S112).
Then, the fitness calculation unit 104 notifies the provisional optimum parameter to the provisional optimum parameter update unit 103 (step S113).
As a result, the provisional optimum parameter update unit 103 updates the provisional optimum parameter (step S114).

Then, in the state updated to the provisional optimum parameter, the process proceeds to step S101 again, and thereafter, the same process is performed to set a more optimal base station parameter.
As described above, according to the present embodiment, in the base station parameter calculation process, a genetic algorithm is used, and communication throughput (minimum SINR and average SINR) is used as fitness. Even in this case, the time required to obtain the optimum solution of the base station parameters can be shortened.

In the above description, the case where the transmission power and the transmission frequency are set as base station parameters has been described as an example. However, the base station parameters are not limited to these, and affect the radio wave environment such as the handover threshold and the frequency bandwidth. Any given base station parameter can be selected as appropriate.
In this case, when increasing the number of base station parameters, the amount of calculation increases exponentially. Therefore, in this case, it is also possible to set the fitness determination threshold more strictly, reduce the number of dominant genes, and reduce the effective calculation amount.

  In the above description, the aggregation number of actual communication terminals corresponding to the virtual communication terminal was not considered, but when the aggregation number of actual communication terminals corresponding to one virtual communication terminal is greater than or equal to the specified number, In consideration of the aggregate number of communication terminals, only a range in which the allowable range of SINR dispersion is set in advance may be provided. That is, since parameter calculation section 109 also considers base station parameters having a large SINR variance, it is possible to determine the base station parameters more accurately.

  The radio wave environment analysis unit 108 can also set a higher priority for radio wave environment maps that are used more frequently than the past radio wave environment maps that are stored. As a result, the radio wave environment analysis unit 108 preferentially searches for a map set with a high priority, so that the radio wave environment map search time can be shortened.

  In addition, the radio wave environment analysis unit 108 as the map creation unit uses the past radio wave environment map similar to the created radio wave environment map to supplement the virtual communication terminals in the area where the virtual communication terminals are not extracted. However, the present invention is not limited to this. The radio wave environment analysis unit 108 may estimate the position where the virtual communication terminal appears from the past radio wave environment map similar to the created radio wave environment map by clustering. Thereby, the radio wave environment analysis unit 108 can reduce the time required for clustering.

  Although several embodiments of the present invention have been described, these embodiments are presented by way of example and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, replacements, and changes can be made without departing from the scope of the invention. These embodiments and modifications thereof are included in the scope and gist of the invention, and are included in the invention described in the claims and the equivalents thereof.

DESCRIPTION OF SYMBOLS 10 Control apparatus 11 Local network 20 Base station 30 Communication terminal 40 Chromosome model 100 Wireless communication system 101 Terminal information aggregation part 102 Base station control part 103 Temporary optimal parameter update part 104 Fitness calculation part 105 Fitness comparison part 106 Fitness setting part DESCRIPTION OF SYMBOLS 107 Search number selection part 108 Radio wave environment analysis part 109 Parameter calculation part 110 Parameter setting part 201 Wireless communication part 202 Terminal information aggregation part 203 Terminal information notification part 301 Wireless communication part 302 Terminal information acquisition part 303 Terminal information holding part 304 Terminal information notification Part

Claims (12)

A plurality of radio wave environment maps representing a radio wave environment in the local network area created in advance based on communication parameters collected when a plurality of base stations dispersedly arranged in the local network area perform wireless communication with a communication terminal A storage unit for storing
Estimating communication parameters of a plurality of virtual communication terminals virtually arranged in the local network area with respect to the set base station parameter based on the plurality of radio wave environment maps, evaluating the base station parameter, A calculation processing unit that repeatedly performs a process of calculating each new base station parameter for the plurality of base stations based on a result until a predetermined calculation end condition is satisfied for the calculated base station parameter;
A base station parameter calculation device comprising: The calculation processing unit applies a genetic algorithm to evaluate the base station parameters and calculate the new base station parameters.
The base station parameter calculation apparatus according to claim 1. The calculation processing unit evaluates communication throughput when evaluating the base station parameter.
The base station parameter calculation apparatus according to claim 2. The calculation processing unit includes a minimum communication throughput and an average communication throughput as the communication throughput to be evaluated.
The base station parameter calculation apparatus according to claim 3. The calculation processing unit evaluates the base station parameter having a higher average communication throughput out of the combination of the base station parameters that maximizes the minimum communication throughput.
The base station parameter calculation apparatus according to claim 3 or 4. The calculation processing unit uses SINR (Signal to Interference and Noise power Ratio) as the communication throughput,
The base station parameter calculation apparatus according to any one of claims 3 to 5. The calculation processing unit divides the base station parameter into a plurality of levels of fitness based on the obtained evaluation, and calculates the new base station parameter based on a base station parameter with higher fitness.
The base station parameter calculation apparatus according to any one of claims 2 to 6. The calculation processing unit includes an error between a minimum communication throughput obtained for each base station parameter and a maximum value of the minimum communication throughput, an average communication throughput obtained for each base station parameter, and a maximum value of the average communication throughput. Classifying the base station parameters into a plurality of levels of fitness based on a combination of errors with, and calculating the new base station parameters based on base station parameters with higher fitness.
The base station parameter calculation apparatus according to any one of claims 4 to 6. The base station parameters include an operating frequency and transmission power of the base station,
The base station parameter calculation apparatus according to any one of claims 1 to 8. The communication parameters include the received power of the transmission signal of the base station transmitted to the base station to which the communication terminal corresponds and the physical cell ID of the base station that transmitted the transmission signal.
The base station parameter calculation apparatus according to any one of claims 1 to 9. A plurality of radio wave environment maps representing a radio wave environment in the local network area created in advance based on communication parameters collected when a plurality of base stations dispersedly arranged in the local network area perform wireless communication with a communication terminal A base station parameter calculation method executed in a base station parameter calculation device that calculates base station parameters of a plurality of base stations distributed and arranged in the local network area,
Estimating the base station parameters by estimating communication parameters of a plurality of virtual communication terminals virtually arranged in the local network area with respect to the calculated base station parameters based on the plurality of radio wave environment maps;
A process of repeatedly calculating a new base station parameter for each of the plurality of base stations based on a result of the evaluation until a predetermined calculation end condition is satisfied for the calculated base station parameter;
A base station parameter calculation method comprising: A control program for controlling a base station parameter calculation device for calculating base station parameters of a plurality of base stations distributed and arranged in a local network area by a computer,
The computer,
A plurality of radio wave environment maps representing a radio wave environment in the local network area created in advance based on communication parameters collected when a plurality of base stations dispersedly arranged in the local network area perform wireless communication with a communication terminal Storage means for storing
Estimating communication parameters of a plurality of virtual communication terminals virtually arranged in the local network area with respect to the set base station parameter based on the plurality of radio wave environment maps, evaluating the base station parameter, Calculation processing means for repeatedly calculating the base station parameters for the plurality of base stations based on a result until the predetermined calculation end condition is satisfied for the calculated base station parameters;
Control program to make it function.

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