TWI805964B - Channel optimization support device, channel optimization support method, access point management system and program - Google Patents

Abstract

The invention provides a channel optimization supporting device, which can realize the optimization of channels of multiple access points. The channel optimization support device includes: an objective function generation section that generates an objective function based on variables indicating whether each of the plurality of access points uses each of the plurality of channels; Next, the optimization calculation of the objective function is performed to calculate the channels used by each of the multiple access points.

Description

Channel optimization support device, channel optimization support method, access point management system and program

The present invention relates to a channel optimization support device, a channel optimization support method, an access point management system and a program.

Patent Document 1 discloses that the group to which each cell belongs is determined so that the shortest distance between cells belonging to the same group is constant, and the determination of the group belonging to the determined group is determined in units of the group. The frequency band assigned by each unit is assigned differently for each group. [Prior art literature] [Patent Document]

Patent Document 1: Japanese Patent Laid-Open No. 2005-27189

[Problem to be Solved by the Invention]

Also, in facilities such as schools, a plurality of access points may be densely arranged. When setting a channel for an access point, there are restrictions such as avoiding interference with channels of nearby access points, but when there are multiple access points, channel management is complicated.

The present invention is made in view of the above problems, and its main purpose is to provide a channel optimization support device, a channel optimization support method, an access point management system, and a program that can easily realize channel optimization of multiple access points. [Means to solve the problem]

In order to solve the above problem, a channel optimization support device according to an aspect of the present invention includes: an objective function generating unit that generates an objective function based on variables indicating whether each of the plurality of access points uses each of the plurality of channels; and The optimization calculation unit calculates channels used by each of the plurality of access points by performing the optimization calculation of the objective function under a predetermined restriction condition.

In addition, an access point management system according to another aspect of the present invention includes: a plurality of access points; and an objective function generation unit that generates an objective function based on the information indicating whether or not each of the plurality of access points uses a plurality of channels. the respective variables; the optimization calculation unit executes the optimization calculation of the objective function under prescribed constraints, thereby calculating the channels used by each of the plurality of access points; and the channel setting unit, based on the The calculation result of the calculation unit is optimized, and channels are set for the plurality of access points.

Furthermore, a channel optimization support method according to another aspect of the present invention generates an objective function based on variables indicating whether each of a plurality of access points uses a plurality of channels, and the channel optimization support method generates an objective function by Executing the optimization calculation of the objective function under the prescribed restriction conditions, so as to calculate the channels used by the plurality of access points respectively.

Furthermore, a program according to another aspect of the present invention causes a computer to function as an objective function generation unit and an optimization calculation unit. The objective function generation unit generates an objective function based on whether each of a plurality of access points is using the variables of the plurality of channels; and the optimization calculation unit calculates the channels used by the plurality of access points by performing the optimization calculation of the objective function under a prescribed limit condition. [Effect of the invention]

According to the present invention, it is easy to realize the optimization of the channels of multiple access points.

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

[System Outline] FIG. 1 is a diagram showing an example of an access point management system 100 according to an embodiment. The access point management system 100 includes the channel optimization support device 1 according to the embodiment (hereinafter simply referred to as “support device 1 ”) and the access point group 90 .

The supporting device 1 is, for example, a computer such as a personal computer or a server computer.

The access point group 90 includes a plurality of access points 9 . The plurality of access points 9 are installed, for example, in each room of a one-story or multi-story building B such as a school, a business, or a research facility. In the figure, the X direction and the Y direction are the horizontal direction, and the Z direction is the vertical direction.

The support device 1 and the plurality of access points 9 can communicate with each other via a communication network such as a wired area network (Local Area Network, LAN). The access point 9 is a wireless LAN access point, and connects a wireless LAN client (not shown) to a communication network such as a wired LAN.

2 and 3 are block diagrams showing configuration examples of the access point 9 ( 9A, 9B). The access point 9 is a generic term for the access point 9A and the access point 9B. The number of wireless communication units 91 and 92 using the 5 GHz band differs between the access point 9A and the access point 9B.

Specifically, the access point 9A includes one wireless communication section 91 using the 5 GHz frequency band. The access point 9B includes two wireless communication units 91 and 92 using the 5 GHz frequency band.

In addition, the access point 9A and the access point 9B include a wireless communication unit 97 , a control unit 98 , and a wired communication unit 99 using the 2.4 GHz frequency band. In addition, there may be an access point including three or more wireless communication units using the 5 GHz frequency band.

FIG. 4 is a diagram for explaining channels in the 5 GHz band. The 5 GHz band includes the groupings W52 (5.2 GHz band), W53 (5.3 GHz band), and W56 (5.6 GHz band). The channel width can be 20 MHz, 40 MHz or 80 MHz.

For example, in the W52 group, when the channel width is 20 MHz, 36ch, 40ch, 44ch, and 48ch are used. When the channel width is 40 MHz, use 36ch+40ch, 44ch+48ch. When the channel width is 80 MHz, use 36ch+40ch+44ch+48ch.

FIG. 5 is a block diagram showing a configuration example of the support device 1 . The support device 1 includes a control unit 10 . The control unit 10 includes a central processing unit (Central Processing Unit, CPU), a random access memory (Random Access Memory, RAM), a read only memory (Read Only Memory, ROM), a non-volatile memory, and input and output interface etc. The CPU of the control unit 10 executes information processing according to the program downloaded from the ROM or the nonvolatile memory to the RAM.

Programs can be provided via information storage media such as optical discs or memory cards, or via communication networks such as the Internet or LAN.

The control unit 10 can access the database 2 . The database 2 can be set in the support device 1, or can be set outside the support device 1 and accessed via a communication network.

The display unit 3 displays an image based on a display instruction from the control unit 10 . The display unit 3 can be provided in the support device 1, or can be provided outside the support device 1 and receive display commands via a communication network.

The control unit 10 includes a position acquisition unit 11 , a distance acquisition unit 12 , an objective function generation unit 13 , an optimization calculation unit 14 , a channel setting unit 15 , and an image generation unit 16 . These functional units are realized by the CPU of the control unit 10 executing information processing according to programs.

FIG. 6 is a diagram showing an example of a position database constructed in the database 2 . In the location database, the respective locations of a plurality of access points 9 are registered.

Specifically, the location database includes fields of "identification code", "model", "configuration location" and "configuration layer".

The “identification code” is an identification code for identifying the access point 9 . “Model” indicates the model of the access point 9 . The number of wireless communication units 91 and 92 using the 5 GHz frequency band is determined based on the model.

"Arrangement position" represents the position of the access point 9 in the horizontal direction in XY coordinates. "Arrangement floor" represents the position of the access point 9 in the vertical direction by the number of floors of the building.

[Channel Optimization] Hereinafter, optimization of channel allocation for allocating channels of the 5 GHz frequency band to a plurality of access points 9 will be described.

In this embodiment, the support device 1 calculates the channel allocation in which the number of channels used by the plurality of access points 9 reaches the maximum by performing the optimization calculation.

The optimization calculation unit 14 (see FIG. 5 ) included in the support device 1 is a so-called solver (solver) that performs optimization calculations. Hereinafter, an example in which the optimization calculation unit 14 executes calculations based on linear programming will be described.

FIG. 7 is a diagram showing an example of the channel optimization support method of the embodiment implemented in the access point management system 100 . The control unit 10 of the support device 1 executes the processing shown in the above-mentioned figure according to a program.

First, the control unit 10 acquires the position of each access point 9 from the position database (see FIG. 6 ) ( S11 ; as a process of the position acquisition unit 11 ).

Next, the control unit 10 calculates the distance between the access points 9 based on the positions of the access points 9 ( S12 ; processing as the distance acquisition unit 12 ). Not limited thereto, the control unit 10 may also acquire the distance between the access points 9 registered in the database 2 in advance.

Next, the control unit 10 generates an objective function ( S13 ; processing as the objective function generation unit 13 ), and acquires a predetermined constraint condition ( S14 ). The objective function and constraints are as follows.

Let the variable indicating whether the i-th access point APi uses channel j be ch _ij , set ch _ij =1 when using channel j, and set ch _ij =0 when not using channel j. ch _ij = {0 or 1}

The number of ch _ij is the number of access points×the number of channels (19 channels of 36 ch to 140 ch). Assuming that the number of access points is set to 100, the number of ch _ij becomes 1900, and the number of combinations that ch _ij can adopt becomes ²¹⁹⁰⁰ . (36) (40) (44) (48) … (140) (AP1) ch _1,36 ch _1,40 ch _1,44 ch _1,48 … ch _1,140 (AP2) ch _2,36 ch _2,40 ch _2,44 ch _2,48 … ch _2,140 … … … … … … … (AP100) ch _100,36 ch _100,40 ch _100,44 ch _100,48 … ch _100,140

That is, ch _ij is a variable indicating whether each of the plurality of access points 9 uses each of the plurality of channels.

The objective function aims at maximizing the number of channels used by the plurality of access points 9, and is represented by the maximum value of the sum of ch _ij as in the following equation.

As restriction conditions, the following six restriction conditions are set.

Restriction (1): Each access point 9 uses one or more channels.

Restriction (2): Each access point 9 uses four or less channels. This means a channel width of up to 80 MHz.

Restriction (3): In the case where the access point 9 includes two wireless communication units 91 and 92 using the 5 GHz frequency band (that is, in the case of the access point 9B shown in FIG. 3 ), the two One of the wireless communication units 91, 92 uses four or less channels belonging to the groups W52 and W53, and the other uses four or less channels belonging to the group W56.

Restriction (4): Each access point 9 does not simultaneously use a plurality of channels belonging to different groups among the groups W52 , W53 , and W56 . That is, each access point 9 does not use the channel belonging to the group W52 and the channel belonging to the group W53 at the same time, does not use the channel belonging to the group W52 and the channel belonging to the group W56 at the same time, and does not use the channel belonging to the group W53 at the same time. The channel of the group and the channel belonging to the group of W56. ch _i,36 +ch _i,52 ≤1 ch _i,36 +ch _i,56 ≤1 ...

Restriction (5): Each access point 9 does not use the first channel among the first channel to the fourth channel with the frequency of the group W52, W53 or W56 in ascending order of frequency, and does not use the first channel at the same time. Second channel and third channel, or second channel and fourth channel. That is, in the group of W52, when 36ch is not used, 40ch and 44ch are not used at the same time, nor are 40ch and 48ch used at the same time. In the W53 group, when 52ch is not used, 56ch and 60ch are not used at the same time, and 56ch and 64ch are not used at the same time. In the group of W56, when 100ch is not used, 104ch and 108ch are not used at the same time, nor are 104ch and 112ch used at the same time. ch _i,40 +ch _i,44 ≤1+M (1-ch _i,36 ) ch _i,40 +ch _i,48 ≤1+M (1-ch _i,36 ) … In addition, M is greater than 1 number.

Restriction (6): The same channel is not allocated to a group of access points 9 whose distance is below the threshold. That is, when the distance d _APm,APn between two access points AP _m and AP _n is equal to or less than the threshold n, the same channel is not allocated to these access points AP _m and AP _n . When n≥d _APm,APn ch _m,36 +ch _n,36 ≤1 ch _m,40 +ch _n,40 ≤1 ... ch _m,140 +ch _n,140 ≤1

In addition, in building B, the ceiling and the floor are between the access points 9 that are far away in the vertical direction (Z direction), and radio waves are difficult to propagate in the vertical direction, so the distance between the access points 9 can also be set The vertical component is corrected to be a shorter distance (ie, shorter than the horizontal component) than it actually is. Thereby, the threshold can be shortened apparently in the vertical direction.

Next, the control unit 10 executes the optimization calculation of the objective function under the constraints (1) to (6), and calculates the channel allocation in which the number of channels used by the plurality of access points 9 reaches the maximum (S15; as the optimal optimization calculation unit 14).

Next, the control unit 10 sets channels for the plurality of access points 9 based on the calculated channel allocation ( S16 ; processing as the channel setting unit 15 ). Each access point 9 changes its channel setting so as to use the channel specified by the support device 1 .

Accordingly, in a case where a plurality of access points 9 are densely arranged in a building B such as a school, it is easy to optimize the channel. That is, it is possible to maximize the number of channels used by a plurality of access points 9 while avoiding assigning the same channel to a group of access points 9 that are close together.

Next, the control unit 10 generates images showing the positions and passages of the plurality of access points 9 ( S17 ; as a process of the image generation unit 16 ). The generated image is output to the display unit 3 .

As shown in FIG. 8 , the image shows the following three-dimensional space 3D, that is, a plurality of objects OB corresponding to each of the plurality of access points 9 are arranged at positions corresponding to the actual positions of the access points 9 and aligned with the allocated The frequency of the channel corresponds to the altitude. In addition, it is preferable that the viewpoint of the image can be changed according to the operation of the user.

The XY axes in the image represent the position of the access point 9 . The position of the access point 9 is based on the "configured position" of the position database (see FIG. 6 ). The axis orthogonal to the XY axis represents the frequency of the channel allocated to the access point 9 . Generate images separately for each layer.

The object OB is formed in a cylindrical shape, and each access point 9 is distinguished by color. The position of the central axis of the cylindrical object OB corresponds to the position of the access point 9 , and the height of the cylindrical object OB indicates the channel allocated to the access point 9 and the channel width.

The radius of the cylindrical object OB is set to a predetermined size based on the distance at which the access points 9 should be separated from each other. Alternatively, the radius of the cylindrical object OB can also be changed according to the output of the access point 9 .

Here, when the objects OB overlap each other, it means that the channels overlap, and when the objects OB do not overlap, it means that the channels do not overlap. Therefore, it is possible to visually grasp whether or not channels overlap.

As shown in Figure 9, the image can also display a two-dimensional space 2D. The horizontal axis in the image represents the position of the access point 9 in the X direction, and the vertical axis represents the frequency of the channel allocated to the access point 9 . That is, the images shown in the above figures are images when viewed or projected in the Y direction on the three-dimensional space 3D (see FIG. 8 ).

Images are generated for each layer and displayed in a row. Therefore, the relationship between the passages in the vertical direction can also be grasped visually.

[Other implementations] The optimization calculation unit 14 (refer to FIG. 5 ) included in the support device 1 may also execute calculations based on nonlinear programming. In this case, the objective function and constraints are as follows.

Set the channel set used by the i-th access point AP _i as v _i . The channel set contains a variable corresponding to each channel, and the variable is set to 1 when the channel is used, and is set to 0 when the channel is not used. v ₁ ={1,0,0,0,…,0} This means that only the first channel (36ch) is used and other channels are not used (equivalent to the following channel set c1).

Let the matrix of the channel set c1 to the channel set c32 available for the access point AP _i be matrix C. (36) (40) (44) (48) (140) (c1) 1 0 0 0 … 0 (c2) 0 1 0 0 … 0 … … … … … (c19) 0 0 0 0 … 1 (c20 ) 1 1 0 0 … 0 (c21) 0 0 1 1 … 0 … … … … … (c29) 1 1 1 1 … 0 … … … … … (c32) 0 0 0 0 … 0

In addition, in this embodiment, the constraints (1) to (5) are realized in the matrix C.

The objective function aims at maximizing the number of channels used by the plurality of access points 9 and is represented by the following equation.

As restrictive conditions, the following two restrictive conditions are set.

Restriction (a): vi has any one of channel set c1 to channel set c32. v _i •1=1

Restriction (b): The same channel is not allocated to a group of access points 9 whose distance is below the threshold. The restriction (b) is the same as the restriction (6). That is, when the distance d _ij between two access points AP _i and AP _j is equal to or less than the threshold n, the same channel is not allocated to these access points AP _i and AP _j . (nd _ij )×(v _i ×C)•(v _j ×C)≥0

The optimization calculation of the objective function is performed under the restriction condition (a) and the restriction condition (b), thereby calculating the channel allocation in which the number of channels used by the plurality of access points 9 reaches the maximum.

As mentioned above, although embodiment of this invention was described, this invention is not limited to embodiment demonstrated above, It goes without saying that various changes can be made by those skilled in the art.

For example, the objective function generated in S13 may also include weight coefficients of multiple access points 9 . That is, in the objective function, by assigning a larger weight coefficient to the access point 9 with a higher priority order, the access point 9 with a higher priority order can be prioritized to maximize the number of channels.

Furthermore, the distance between the access points 9 calculated in S12 may be a distance corrected according to the directivity of the access points 9 . For example, when calculating the distance to an access point 9 having directivity in a predetermined direction, the threshold value can be extended apparently in the direction by correcting so that the component of the direction is longer than it actually is.

Furthermore, any one of the access points 9 constituting the access point group 90 may also serve as the support device 1 . At this time, the control unit 98 of the access point 9 operates in the same manner as the control unit 10 of the support device 1 .

1: Channel optimization support device 2: Database 2D: two-dimensional space 3: Display part 3D: three-dimensional space 9, 9A, 9B: access points 10: Control Department 11: Position Acquisition Department 12: Distance acquisition part 13: Objective function generation part 14:Optimization Calculation Department 15: Channel setting department 16: Image Generation Department 90: access point group 91, 92: Ministry of Wireless Communications (5 GHz frequency band) 97: Ministry of Wireless Communications (2.4 GHz frequency band) 98: Control Department 99: Department of Wired Communications 100: Access point management system B: building OB: object S11～S17: Steps

FIG. 1 is a diagram showing an example of an access point management system according to an embodiment. FIG. 2 is a diagram showing a configuration example of an access point. FIG. 3 is a diagram showing a configuration example of an access point. FIG. 4 is a diagram for explaining channels in the 5 GHz band. FIG. 5 is a diagram showing a configuration example of the channel optimization support device according to the embodiment. FIG. 6 is a diagram showing an example of a location database. FIG. 7 is a diagram showing an example of steps of the channel optimization support method according to the embodiment. FIG. 8 is a diagram showing an example of an image showing the position and passage of an access point. FIG. 9 is a diagram showing an example of an image showing the position and passage of an access point.

1: Channel optimization support device

2: Database

3: Display part

10: Control Department

11: Position Acquisition Department

12: Distance acquisition part

13: Objective function generation part

14:Optimization Calculation Department

15: Channel setting department

16: Image Generation Department

Claims (18)

A channel optimization support device including: an objective function generation section that generates an objective function based on variables indicating whether each of a plurality of access points uses a plurality of channels; performing the optimization calculation of the objective function under restricted conditions, so as to calculate the channels used by each of the plurality of access points, wherein the optimization calculation of the objective function is for the channels used by the plurality of access points The number of channels is maximized. The channel optimization support device according to claim 1, wherein the objective function represents a sum of the variables, and the optimization calculation section performs an optimization calculation that maximizes the sum of the variables. The channel optimization support device according to claim 1, further comprising a distance acquisition unit, the distance acquisition unit acquires the distance between the plurality of access points, and the restriction condition includes the following condition: the wrong distance is a threshold value The following groups of access points are assigned the same channel. The channel optimization support device according to claim 3, wherein the distance is a distance obtained by correcting a component in the vertical direction to be shorter than the actual distance. The channel optimization support device according to any one of claim 1 to claim 4, wherein the restriction condition includes the following condition: each access point uses more than one channel. The channel optimization support device according to any one of claim 1 to claim 4, wherein the restriction condition includes the following condition: each access point uses a channel equal to or less than a predetermined natural number. The channel optimization support device according to any one of claim 1 to claim 4, wherein the restriction conditions include the following conditions: when the access point includes a plurality of wireless communication units, the plurality of wireless The communication unit uses channels equal to or less than a predetermined natural number belonging to mutually different groups. The channel optimization support device according to any one of claim 1 to claim 4, wherein the restrictive condition includes a condition that each access point does not simultaneously use a plurality of channels belonging to different groups. The channel optimization support device as described in any one of claim 1 to claim 4, wherein the restriction conditions include the following conditions: each access point does not use the first frequency that belongs to the group from small to large In the case of the first channel among the channels to the fourth channel, the second channel and the third channel, or the second channel and the fourth channel are not used at the same time. The channel optimization support device according to any one of claim 1 to claim 4, wherein the optimization calculation is performed by a linear programming method. The channel optimization support device according to any one of claim 1 to claim 4, wherein the optimization calculation is performed by a nonlinear programming method. The channel optimization support device according to any one of claim 1 to claim 4, wherein the objective function includes respective weight coefficients of the plurality of access points. The channel optimization support device according to claim 3 or claim 4, wherein the distance is a distance corrected according to the respective directivities of the plurality of access points. The channel optimization support device according to any one of claim 1 to claim 4, further comprising a position acquisition unit that acquires the positions of the plurality of access points, and also includes an image generation unit , the image generating unit generates an image showing that a plurality of objects corresponding to each of the plurality of access points is arranged at a position corresponding to the position of the access point and at a height corresponding to the frequency of the channel Space. The channel optimization support device according to claim 14, wherein the plurality of objects are arranged in the space with a size corresponding to the output of the access point. An access point management system, including: a plurality of access points; an objective function generating unit that generates an objective function, the objective function is based on the Whether each of the plurality of access points uses the variables of the plurality of channels; the optimization calculation part calculates the respective variables of the plurality of access points by performing the optimization calculation of the objective function under the specified restriction conditions. channels to use, wherein the optimization calculation of the objective function is to maximize the number of channels used by the plurality of access points; and a channel setting section, based on a calculation result of the optimization calculation section, Channels are set by the plurality of access points. A channel optimization support method of generating an objective function based on variables indicating whether each of a plurality of access points uses a plurality of channels, by performing an optimization calculation of the objective function under prescribed restriction conditions, Thus, channels used by the multiple access points are calculated, wherein the optimization calculation of the objective function is to maximize the number of channels used by the multiple access points. A program for causing a computer to function as an objective function generation unit and an optimization calculation unit: the objective function generation unit generates an objective function based on variables indicating whether each of a plurality of access points uses a plurality of channels ; and the optimization calculation section calculates the channel used by each of the plurality of access points by performing the optimization calculation of the objective function under a prescribed constraint condition, wherein the optimal calculation of the objective function The optimization calculation is to maximize the number of channels used by the multiple access points.

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