JP2006005603A - Data communication device, data communication method, data communication program, communication channel selection device and communication channel selection program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that a communication channel is not changed until the communication speed decreases and an optimum communication can not be always selected since comparisons with other communication channels can not be made while no communication error occurs. <P>SOLUTION: The number of access points using a channel CH is detected by passive scanning in a step S120 and false radio wave density of each communication channel is calculated based upon the detected number of access points in a step S130; and the communication channel having the least false radio wave density is searched for in order from "1" in a step S160 and thus a choice is made from the number of access points based upon the use states of respective communication channels to select a communication channel over which efficient communication can be performed in a relatively simple method. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a data communication device, a data communication method, a data communication program, a communication channel selection device, and a communication channel selection program for a plurality of individual wireless terminals to wirelessly transmit and receive data to and from a common access point.

In recent years, an access point (data communication apparatus), which is a repeater for a wireless LAN, has been used as a device for connecting a plurality of computers (wireless terminals) at remote locations to the Internet.
The access point is connected to a network such as the Internet by wire, and the access point and the computer are connected wirelessly. A predetermined frequency band is assigned for such wireless communication, and a plurality of communication channels (ch1 to ch13) are set in order to further divide the frequency band into a plurality of bands. Yes.

Which communication channel is used depends on the user, and it is assumed that the communication channel is appropriately changed.
However, in reality, since the user has little understanding of the communication channel, the communication channel (for example, ch11) as it is at the time of product shipment is often used.
Since the wireless connection performs packet data communication, data communication between a plurality of pairs of transmission / reception terminals using the same communication channel is possible, but the efficiency is reduced because idle time is used.
On the other hand, a technique is known in which, when the communication speed is reduced during wireless communication, the status of each communication channel is determined based on a communication error, and a communication channel without a communication error is selected and used. What is shown to patent document 1 and patent document 2 is known.
JP 2003-298591 JP2003-244159

The conventional data communication apparatus described above has the following problems.
When the product is used as shipped without changing the communication channel, data communication is performed using only the same communication channel, so the communication speed is limited and the efficiency is not good.
When another communication channel is determined based on a communication error when the communication speed decreases, the communication channel cannot be changed until the communication speed decreases, and if there is no communication error, comparison between other communication channels is possible. It is not always possible to select the optimum communication channel.

  The present invention has been made in view of the above-described problems, and provides a data communication device, a data communication program, a data communication method, a communication channel selection device, and a communication channel selection program that can more easily use an optimal communication channel. For the purpose of provision.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided a plurality of communication channels to which a predetermined frequency band is assigned when a plurality of individual wireless terminals wirelessly transmit / receive data to / from a common access point. A data communication apparatus as the access point that uses any one of the communication channels, and a determination unit that determines a use situation for each communication channel, based on a predetermined condition based on the use situation A selection means for selecting a communication channel suitable for use and a transmission / reception means for transmitting / receiving data using the selected communication channel are provided.

  In the invention according to claim 1 configured as described above, it is assumed that a plurality of individual wireless terminals are assigned a predetermined frequency band when wirelessly transmitting and receiving data to and from a common access point. One of the communication channels is used. Here, in the data communication apparatus as the access point, the determining means determines the usage status for each communication channel, and the selecting means is a communication suitable for use based on a predetermined condition based on the usage status. Since the channel is selected, the transmission / reception means transmits / receives data using the selected communication channel.

That is, the use situation including, for example, whether or not the communication channel is used in each communication channel is determined, and the optimum communication channel is selected from the use situation.
As a condition for selecting a communication channel based on the use situation, various methods can be applied. As an example, the invention according to claim 2 is the data communication apparatus according to claim 1, wherein the selection means includes: The channel is selected so as to eliminate the bias of the communication channel being used.

In the invention according to claim 2 configured as described above, the communication channel to be used is selected so as to eliminate the bias of the communication channel being used. As a result, the usage becomes as uniform as possible and contributes to improving the communication efficiency.
Further, the invention according to claim 3 is configured such that the selection means selects a communication channel that is not being used.
In the invention according to claim 3 configured as described above, when selecting a communication channel, a communication channel that is not used is selected. If there is a communication channel that is not used, selecting this channel contributes to improving communication efficiency.
Further, the invention according to claim 4 is configured such that the determination means reflects the influence on the neighboring communication channel by using each communication channel in the usage status.
In the case of a wireless LAN, channels that can be selected are ch1 to ch13. However, when using ch11, adjacent communication channels such as ch10 and ch12 and neighboring communication channels such as ch9 and ch13 are also affected by communication. In such a case, the communication efficiency cannot be determined only by using the individual communication channels.

  On the other hand, in the invention according to claim 4 configured as described above, since the influence on the neighboring communication channel is reflected by using each communication channel in determining the usage status, It is possible to select a communication channel that can actually improve communication efficiency.

Furthermore, the invention according to claim 5 is configured such that the determination means determines a use situation according to the number of access points using the communication channel for each communication channel.
Although it is possible to determine the usage status by measuring the amount of data actually communicated for each communication channel, it is cumbersome. On the other hand, the amount of data that can be communicated can be determined by the number of access points set to use each communication channel. For this reason, in the invention concerning Claim 5 comprised as mentioned above, the said determination means detects the number of the access points which are using the said communication channel for every communication channel, and a usage condition according to the same number Determine.

As an example of a method for detecting the number of access points, the invention according to claim 6 is characterized in that the determination means determines the number of access points based on a beacon transmitted from an access point using each communication channel. It is as composition to do.
If some request is output to the access point and the number of access points is detected after waiting for the response, a request is issued, a response to the request itself or a response is generated, and a packet is used for each request. . As a result, communication traffic is naturally reduced, which is inefficient.

  On the other hand, in the invention according to claim 6 configured as described above, the number of access points based on beacons periodically transmitted by access points using each communication channel under existing conditions. Therefore, a passive scan is performed, and the number of access points is detected without reducing traffic due to a special request. Furthermore, the invention according to claim 7 is characterized in that the determination means gives the largest weight to the number of access points to the communication channel being used, and assigns a weight that decreases in size as the communication channel moves away from the center. And the usage status of each communication channel is reflected.

  In the invention according to claim 7 configured as described above, the access point does not directly reflect the number of access points for each communication channel, but assigns the highest weight to the communication channel used by each access point. And the usage status of the communication channel. Further, a weight that decreases in size as the communication channel is centered is given to the number of the access points, and is reflected in the usage status of each communication channel.

More specifically, in the invention according to claim 8, the determination means gives 6 to the communication channel being used as the weighting, and the weighting of 3: 2: 1 sequentially every time one communication channel leaves. It is as composition to give.
In the invention according to claim 8 configured as described above, if there are two access points in ch10, “2”, which is the number of access points, gives “6”, which is a weight to ch10. This gives a contribution of “12”, is given a weight of “3” for ch9 and ch11 and becomes a contribution of “6”, and is given a weight of “2” for ch8 and ch12 to “4”. "1" is given to the ch7 and ch13, and "2" is contributed. As a result, in ch7 to ch13, the usage status is “2”, “4”, “6”, “12”, “6”, “4”, “2”.

When there is an access point that uses another communication channel, the same weight is given to reflect the use status of the neighboring channel. When reflected on the usage status from a plurality of communication channels, the usage status values may be added sequentially.
Such weighting can be changed as appropriate depending on the nature of the radio frequency band to be used, the modulation method, and the like. Play.
Various methods can be applied as a method for selecting any communication channel based on the usage status. As an example, the invention according to claim 9 is such that the selection means communicates when there are a plurality of communication methods. The communication channel is selected while avoiding a slow communication method.
In the invention according to claim 9 configured as described above, when there are a plurality of communication methods, a communication channel is selected avoiding a communication method having a low communication speed.
Further, the invention according to claim 10 is configured such that the usage status of the communication channel is determined every predetermined time, and the selection means changes the communication channel based on the usage status.
In a wireless LAN or the like, data communication is not always performed on a specific communication channel. Therefore, it can be said that the usage status of each communication channel changes with time. For this reason, in the invention concerning Claim 10 comprised as mentioned above, the use condition of the said communication channel is determined for every predetermined time. Then, if necessary, the selection means changes the communication channel based on the use situation. Of course, there is no significant change in the usage status, and in that case, the communication channel may not be changed.

Furthermore, the invention according to claim 11 is configured such that the upper communication channel is not changed when the wireless terminal is communicating with the data communication apparatus.
If the communication channel is changed while the wireless terminal is communicating with the data communication device, communication will be hindered. In the invention according to claim 11 configured as described above, during the communication, Do not change the upper communication channel.
Furthermore, the invention according to claim 12 is a data communication apparatus for performing data transmission / reception through any one of the communication channels selected from a plurality of communication channels to which a predetermined frequency band is assigned. A determination means for determining the usage status for each communication channel, a selection means for selecting a communication channel suitable for use based on a predetermined condition based on the usage status, and data of the data using the selected communication channel And a transmission / reception means for performing transmission / reception.

  As described above, it is not always necessary that the method of selecting the communication channel to be used by determining the usage status is limited to a substantial device, and it can be easily understood that the method also functions. For this reason, the invention according to claim 13 uses any one of a plurality of communication channels to which a predetermined frequency band is assigned, and a plurality of individual wireless terminals wirelessly communicate with a common access point. A data communication method for transmitting and receiving data, wherein a determination step for determining a use situation for each communication channel and a selection for selecting a communication channel suitable for use based on a predetermined condition based on the use situation And a transmission / reception step of transmitting / receiving data using the selected communication channel.

That is, it is not necessarily limited to a substantial apparatus, and there is no difference that the method is also effective.
By the way, such a data communication device may exist independently, or may be used in a state of being incorporated in a certain device. The idea of the invention is not limited to this and includes various aspects. . Therefore, it can be changed as appropriate, such as software or hardware.

When the software of the data communication apparatus is embodied as an example of the idea of the invention, it naturally exists on a recording medium in which such software is recorded and can be used.
As an example, the invention according to claim 14 uses any one of a plurality of communication channels to which a predetermined frequency band is assigned, and a plurality of individual wireless terminals are connected to a common access point. A data communication program for transmitting and receiving data wirelessly, wherein a determination function for determining a use situation for each communication channel and a communication channel suitable for use based on a predetermined condition are selected based on the use situation The configuration includes a selection function and a transmission / reception function for transmitting / receiving data using the selected communication channel.

  Of course, the recording medium may be a magnetic recording medium, a magneto-optical recording medium, or any recording medium that will be developed in the future. In addition, the duplication stages such as the primary duplication product and the secondary duplication product are equivalent without any question. In addition, even when the communication method is used as a supply method, the present invention is not changed.

Further, even when a part is software and a part is realized by hardware, the idea of the invention is not completely different, and a part is stored on a recording medium and is appropriately changed as necessary. It may be in the form of being read.
When the present invention is implemented by software, a configuration using hardware or an operating system may be used, or may be implemented separately from these. For example, even if it is a variety of arithmetic processing, if it can be processed by calling a predetermined function in the operating system, it can also be input from hardware without calling such a function. is there. It can be understood that the present invention can be implemented with only this program in the process in which the program is recorded and distributed on the medium even though it is actually realized with the intervention of the operating system.

When the present invention is implemented by software, the present invention is not only realized as a medium storing a program, but the present invention is naturally realized as a program itself, and the program itself is also included in the present invention.
Further, if only the communication channel to be used is selected as described above, it is not always necessary to transmit and receive data by itself, and the present invention can also be applied as an apparatus for simply selecting a communication channel. As an example, when a plurality of individual wireless terminals wirelessly transmit / receive data to / from a common access point, a communication channel to be used is selected from a plurality of communication channels assigned a predetermined frequency band. A communication channel selection apparatus comprising: a determination unit that determines a usage status for each communication channel; and a selection unit that selects a communication channel suitable for use based on a predetermined condition based on the usage status. It is as composition to do.

  Of course, the operation is the same as described above except for data transmission / reception. Further, the present invention can be realized as a communication channel selection program for realizing such a device. In the invention according to claim 16, a plurality of individual wireless terminals wirelessly transmit / receive data to / from a common access point. In performing, a communication channel selection program for selecting a communication channel to be used from among a plurality of communication channels assigned a predetermined frequency band, a determination function for determining a use situation for each communication channel, The computer is configured to realize a selection function for selecting a communication channel suitable for use based on a predetermined condition based on the use situation.

  Needless to say, the various variations described above are equally applicable to any of the apparatus, method, and program.

As described above, the present invention can provide a data communication apparatus capable of realizing efficient data transmission / reception since the communication status is selected in advance by determining the usage status.
Moreover, according to the invention concerning Claim 2, the bias of the communication channel currently used can be eliminated and efficiency can be improved.
Further, according to the invention of claim 3, since the selecting means selects any communication channel that is not used, the bias of the communication channel that is used is inevitably eliminated, and the efficiency is improved. Can be made.
Furthermore, according to the fourth aspect of the present invention, it is possible to more accurately reflect the usage status when it affects neighboring communication channels.
Furthermore, according to the invention concerning Claim 5, a use condition can be easily reflected using the number of the access points which are using each communication channel.
According to the sixth aspect of the present invention, when a passive scan based on a beacon transmitted from an access point is performed, the number of access points can be detected without adversely affecting communication traffic.
Furthermore, according to the invention concerning Claim 7, it becomes possible to determine the use condition close | similar to use of an actual electromagnetic wave by giving weighting to the number of access points.
Further, according to the eighth aspect of the present invention, it is possible to determine a use situation that is closer to the actual use of radio waves.
Furthermore, according to the invention concerning Claim 9, communication efficiency can be improved more reliably by avoiding a communication system with a low communication speed.
Furthermore, according to the invention concerning Claim 10, it becomes possible to select an optimal communication channel according to the change of time.
Further, according to the invention of claim 11, it is possible to avoid the risk of affecting the wireless terminal in communication.
Furthermore, according to the invention concerning Claims 12, 13, and 14, the data communication apparatus, the data communication method, and the data communication program which have the same effect can be provided.
Moreover, according to the invention concerning Claims 15 and 16, the communication channel selection apparatus and communication channel selection program which show | play the same effect can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

In order to further clarify the configuration and operation of the present invention described above, embodiments of the present invention will be described in the following order.

A. First Example A-1. Network configuration A-2. Details of optimum communication channel selection processing A-3. Effect B. Summary

A. Example:
A-1. Network configuration:
FIG. 1 is an explanatory diagram showing a hardware configuration of a network environment according to the first embodiment of the present invention, and FIG. 2 is an explanatory diagram showing a configuration of an access point (data communication apparatus).

In this network environment, in the wireless communication area of the wireless LAN, the wireless terminals 50, 60, and 70 can access the server SV of the Internet IN connected in the wired environment CL via the access points 20a, 20b, and 20n. It has become.
As shown in FIG. 1, an access point (wireless base station: data communication device) 20 (generally 20a, 20b, and 20n) that is a wireless LAN repeater is installed in the wireless communication area. As shown in FIG. 2, the access point 20 includes a CPU 11, a ROM 12, a RAM 13, a non-volatile storage device 14 such as a hard disk, a WAN port 17 as a network interface, a wired LAN, and the CPU 11. The LAN port 22, the wireless communication interface 18, the display controller 15, and the input / output controller 16 are provided.

  The ROM 12 stores various programs relating to communication with the wireless terminals 50, 60, and 70 in the wireless communication area and connection to the Internet IN and data necessary for executing the programs. Here, as an example of the program, a communication channel setting program shown in FIGS. 3 to 6 is included.

  The wireless communication interface 18, the transmitter 25, and the receiver 26 can transmit / receive data by selecting any one of 13 channels of communication channels ch1 to ch13 set in a predetermined frequency band (2.4 GHz band). It is. The communication channel is selected by the communication channel setting program described above. Further, there are communication methods of 11 Mbps communication speed based on IEEE802.11b (hereinafter simply referred to as 11b method) and 54 Mbps communication speed based on IEEE802.11g (hereinafter simply referred to as 11g method). However, which one can be used is determined by a specific hardware configuration. Although not shown, a timer circuit that realizes a time measuring function is also provided.

  Wireless LAN adapters 52, 62, and 72 are attached to the wireless terminals 50, 60, and 70 as wireless LAN connection devices that can transmit and receive radio waves to and from the access point 20. By incorporating the device drivers of the wireless LAN adapters 52, 62, 72 into the wireless terminals 50, 60, 70, the wireless terminals 50, 60, 70 recognize the attached wireless LAN adapters 52, 62, 72, The wireless LAN adapters 52, 62, and 72 can be controlled.

  Radio terminals 50, 60, and 70 as computers that have entered the wireless communication area transmit and receive radio waves using a predetermined communication channel between the attached wireless LAN adapters 52, 62, and 72 and the access point 20. Thus, communication with the access point 20 is performed wirelessly. The access point 20 and the wireless LAN adapters 52, 62, and 72 can convert the exchanged data into a format suitable for communication, so-called a packet, whereby the wireless terminals 50, 60, 70 and the access point 20 It is possible to send and receive data between the two.

  When the access point 20 receives access from the wireless terminals 50, 60, and 70, the access points 20a, 20b, and 20g need to specify a communication channel used for data communication. Each access point 20a, 20b, 20g appropriately transmits a beacon including an SSID as an ID after specifying the communication channel, and the wireless terminals 50, 60, 70 transmit wireless LAN adapters 52, 62, 72, respectively. A passive scan is performed by spending a predetermined period at the time of activation, and various information on the access points 20a, 20b, 20g existing in the wireless communication area can be acquired. That is, in the passive scan, it is determined whether or not a beacon can be received while the communication channel is sequentially increased (lowered) from ch1 to ch13. If the beacon can be received, the access points 20a and 20b are determined from the information included in the beacon. , 20g SSID and communication method will be acquired.

  Here, the wireless terminals 50, 60, and 70 recognize the access points 20a, 20b, and 20g by the SSID, specify the access points 20a, 20b, and 20g to be connected, and then determine the communication channel from the information included in the beacon. To identify. Therefore, it is the access point 20 side that determines the communication channel independently, not the wireless terminals 50, 60, 70 side.

A-2. Details of the optimal communication channel selection process:
3 to 6 are flowcharts showing the communication channel setting program. FIG. 3 corresponds to the main flow. In step S110, “1” as an initial value is set to the variable CH for loop processing, and the processing of steps S120 to S150 is repeated for a predetermined channel for each communication channel. The communication channel to be used is finally determined in step S160. In this sense, the process of steps S110 to S150 corresponds to a determination function (determination means, determination process), and the process of step S160 corresponds to a selection function (selection means, selection process).

  The variable CH given the initial value in step S110 is incremented by “1” in step S140, and the processes in steps S120 and S130 are repeated until it is determined in step S150 that it exceeds “13”. . Since communication channels include ch1 to ch13, each loop can be covered by this loop processing.

  In this loop processing, first, in step S120, the number of access points using the channel CH is detected by passive scanning. In this embodiment, in order to optimize communication efficiency, detection is made including the type of communication method. That is, the number Nb of 11b access points and the number Ng of 11g access points are counted separately. However, depending on the application, the number N (= Nb + Ng) may be used.

  Next, in step S130, the pseudo radio wave density for each communication channel is calculated. In the wireless LAN communication standards IEEE802.11b and IEEE802.11g described above, the 13 channels can not provide a completely individual communication environment, but if one communication channel is used, data can be transmitted and received on neighboring communication channels. It has a considerable effect. The degree of influence decreases as the value of the communication channel increases with the communication channel to be used as the center. If this degree of influence is expressed as weighting, assuming that the central communication channel is 1, the channel value is approximately 1/2 in the communication channel with a distance of ± 1 and the channel value is 1/3 in the communication channel with a distance of ± 2. It can be expressed as 1/6 in a communication channel whose channel value is ± 3 away.

  In view of such a technical background, the pseudo radio wave density is calculated according to the flowchart shown in FIG. First, in step S205, “1” as an initial value is set to the variable VCH for loop processing, and in step S210, the number of access points having the channel CH detected by the passive scan as the communication channel is substituted for the variable. Although indicated as Nbg in the flowchart, the number of access points corresponding to the variables Nb, Ng, and N (= Nb + Ng) is substituted for each communication method.

  Thereafter, steps S215 to S260 are repeated, and the variable PTbg (VCH) for the pseudo radio wave density prepared for each communication channel is calculated while the variable VCH becomes “1” to “13”. Become. Specifically, in step S215, it is determined whether or not the current variable VCH has a difference of ± 3 from the value of the current communication channel. If YES, in step S220, each communication method is simulated. The radio wave density is calculated and substituted for the variable PTbg (VCH). Here, PTbg (VCH) and Nbg are shown in the flowchart, but specifically, the calculation is performed for each communication method. In the calculation formula, what is added to the pseudo radio wave density PTbg (VCH) before calculation is a value obtained by multiplying the number Nbg of access points by “1”. As described above, the degree of influence of a communication channel having a numerical value of ± 3 centering on the communication channel to be used is 1/6. However, it is possible to simplify the arithmetic processing by calculating with an integer. If the weight is set to “1” with respect to 1/6 of the influence degree of the communication channel having the numerical value of ± 3, the weighting is 2 with respect to 1/3 of the influence degree of the communication channel having the numerical value of ± 2. Similarly, a weight of 3 is appropriate for 1/2 of the degree of influence of a communication channel having a numerical value of ± 1, and a weight of 6 for a degree of influence of a central communication channel. Is appropriate. In steps S215, S225, S234, and S245, each is a communication channel having a numerical value of ± 3, a communication channel having a numerical value of ± 2, or a communication channel having a numerical value of ± 1 around the communication channel to be used. Or the central communication channel, and if it corresponds to each, the value obtained by multiplying the number of access points Nbg by the weight in steps S220, S230, S240, and S250 is calculated as the value of the pseudo radio wave density. .

Of course, if multiple communication channels are used, the degree of influence will be cumulative, so if the number of access points is detected for each communication channel, the pseudo radio wave density mentioned above for all of the neighboring channels that will be affected each time. Perform the calculation.
When the above calculation is performed, the loop processing variable VCH is incremented by “1” in step S255, and the process is repeated until it is determined in step S260 that the variable VCH exceeds “13”.
When the loop processing variable CH is changed from “1” to “13” and the loop processing variable VCH is changed from “1” to “13” each time, the above-described processing is repeated. That is, the usage status is determined including the degree of influence received by data transmission / reception using another communication channel.

Therefore, an optimum communication channel is determined based on the pseudo radio wave density calculated as described above in step S160 shown in FIG.
5 and 6 show detailed flowcharts thereof.
First, in step S305, an initial value is set for each variable to be used. Here, “1” is substituted into the variable CH for loop processing, “65535” is substituted into the variable W for the minimum pseudo radio wave density value, and “0” is substituted into the variable chan for the communication channel with the minimum pseudo radio wave density. Note that the value assigned to the variable W is the maximum positive integer value represented by 2 bytes, and represents the upper limit value based on the fact that each variable is a 2-byte variable.

  After setting the initial value, in step S310, it is determined whether or not the access point detected in the current communication channel represented by the variable CH adopts the 11b method. In this embodiment, even if there are other access points that will use the same communication channel, an attempt is made to avoid a communication channel having an 11b access point as much as possible. The theoretical value of the communication speed in the 11b system is 11 Mbps, whereas the theoretical value of the communication speed in the 11g system is 54 Mbps. This is reflected in the difference in communication time required to communicate the same amount of data. Therefore, even if it is necessary to use the same communication channel in a situation where there are a plurality of access points, coexistence with 11b access points is avoided as much as possible, and a decrease in communication speed is avoided.

  If the access point is not the 11b system, it is determined in step S315 whether or not the 11g system pseudo radio wave density PTg (CH) in the communication channel of the variable CH is smaller than the current minimum pseudo radio wave density value W. At this time, only when the communication channel is “11” exceptionally, the case where the pseudo radio wave density PTg (CH) is the same as the current minimum pseudo radio wave density value W is also included. That is, it is determined whether or not the pseudo radio wave density value is smaller than the minimum pseudo radio wave density value stored in the work variable W while changing the communication channel. Update the variable chan by substituting the variable value of the current communication channel.

Thereafter, the variable CH is incremented by “1” in step S325, and the processes in steps S310 to S325 are repeated until it is determined in step S330 that “13” has been exceeded.
If it is determined that “13” is exceeded, it is determined in step S335 whether or not the variable chan as the temporary channel value is “0”. If it is not “0”, it is determined that an optimum communication channel has been obtained. Exit. As described above, in order to avoid coexistence in the 11b system, it is determined in step S310 whether the access point using each communication channel is in the 11b system. If the access point is in the 11b system, the minimum pseudo radio wave density value W is updated. And temporary channel chan are not updated. For this reason, if there are only 11b access points, the temporary channel value remains the initial value “0” and is not updated. Therefore, if the temporary channel value remains at the initial value “0”, it is determined that coexistence in the 11b method is unavoidable, and “1” is newly assigned to the loop processing variable CH in step S355. Then, the one having the smallest value of the pseudo radio wave density including the 11b method is searched.

  The process of searching for the communication channel having the minimum pseudo radio wave density using the minimum pseudo radio wave density value W or the temporary channel chan is the same as in the case of steps S315 and S320 described above. The only difference is that there is no determination process in step S310 to avoid coexistence of the 11b method. Therefore, it is possible to surely detect the communication channel having the minimum pseudo radio wave density this time.

Next, the operation of the present embodiment configured as described above will be described.
FIG. 7 shows, as a table, a situation in which the pseudo radio wave density is calculated when one access point that uses ch1 and ch12 is installed as a communication channel.
Since one access point that uses the communication channel of ch1 is installed, the value of the pseudo radio wave density is obtained from ch1 to ch4 that are neighboring communication channels. In addition, since one access point using the communication channel of ch12 is installed, the value of the pseudo radio wave density is obtained from ch9 to ch13, which are the neighboring communication channels, with ch12 as the central communication channel. In the figure, “x” indicates a point assigned by reflecting weighting to an access point adopting the 11g method. That is, the number of “x” described in the numerical value line of the channel number is represented as the pseudo radio wave density. In the process of step S130, the contents of the table are created.

  Subsequently, in step S160, the communication channel with the smallest pseudo radio wave density is sequentially searched from “1”. As is apparent from the figure, when the channel number is sequentially increased and the communication channel becomes “5”, the value of the minimum pseudo radio wave density value W becomes minimum and is not updated thereafter. As a result, the “5” channel is selected as the optimum communication channel.

On the other hand, FIG. 8 shows the state of the table when the access point that has selected the communication channel to be used in this way is the 11b system. In this table, the pseudo radio wave density is attached as “o” so that it can be distinguished from the 11 g pseudo radio wave density.
In this case, the same table is created in step S130, and a communication channel with the smallest pseudo radio wave density is searched for in step S160. However, since there is an 11b access point this time, when the channel number is sequentially increased, the channel number “5” is not compared with the minimum pseudo radio wave density. The pseudo radio wave density becomes the same “1” when the channel numbers are “8” and “9”, but the minimum pseudo radio wave density or the density W is updated at the time of the channel number “8” that is the smallest first. And selected.

  It is also possible to avoid neighboring communication channels that are affected by the 11b system as a range to avoid the coexistence of the 11b system. In this case, the pseudo radio wave density is not compared when the channel number is “8”, and the minimum pseudo radio wave density value W is updated and selected when the channel number is “9”.

  By the way, the communication channel selection / determination process as described above is not limited to the case where an access point 20 is newly installed. In the wireless LAN environment including the wireless terminals 50, 60, 70, the communication terminals 50, 60, 70 may increase or decrease, or the access points themselves may increase / decrease. For this reason, as shown in FIG. 9, when a predetermined period elapses, the use state of each communication channel may be determined at each access point, and the optimum communication channel may be selected at that time.

  That is, as shown in the figure, it is determined whether or not a predetermined time has elapsed in step S405, and if the predetermined time has elapsed, it is determined whether or not the wireless terminal is communicating in step S415. The reason why it is determined in step S415 whether or not the wireless terminal is communicating is that if the communication channel is changed during communication with the wireless terminal, communication is interrupted, which may adversely affect the wireless terminal. If not communicating with the wireless terminal, the communication channel is reset in step S420. The contents are exactly the same as those shown in FIG. If it is determined in step S405 that the predetermined time has not elapsed, normal communication processing is executed in step S410, and it is determined again in step S405 whether the predetermined time has elapsed.

  The communication channel selection process described above is not necessarily performed by a program or the like installed in the access point, and can be realized by the wireless terminals 50, 60, and 70 equipped with the wireless LAN adapters 52, 62, and 72. In this case, since the process up to selecting the optimum communication channel can be executed, the wireless terminal 50, 60, 70 performs the process to install the access point that does not have the program installed therein. What is necessary is just to obtain | require a communication channel and to set to the communication channel used with the access point which installs the communication channel newly.

  As described above, the number of access points using the channel CH is detected by passive scan in step S120, and the pseudo radio wave density for each communication channel is calculated based on the number of detected access points in step S130. In S160, the communication channel with the lowest pseudo radio wave density is searched sequentially from “1”, and by selecting from the number of access points based on the usage status of each communication channel, the efficiency can be improved with a relatively simple method. A communication channel capable of good communication can be selected.

It is the schematic which shows the network environment concerning one Embodiment of this invention. 2 is an explanatory diagram showing a configuration of an access point 20. FIG. It is a main flowchart which selects a communication channel. It is a flowchart of a process of calculation of a pseudo radio wave density. It is a flowchart of the process which determines an optimal communication channel. It is a flowchart of the process which determines an optimal communication channel. It is a figure which shows the table which calculated the pseudo radio wave density for every communication channel. It is a figure which shows the table which calculated the pseudo radio wave density for every communication channel. It is a flowchart of the process which re-selects an optimal communication channel for every predetermined time.

Explanation of symbols

  20 (20a, 20b, 20n) ... access point

Claims (16)

When the plurality of individual wireless terminals wirelessly transmit / receive data to / from a common access point, the access point uses any one of a plurality of communication channels assigned a predetermined frequency band. The data communication device of
A determination means for determining a use situation for each communication channel;
A selection means for selecting a communication channel suitable for use based on a predetermined condition based on the use situation;
A data communication apparatus comprising: transmission / reception means for transmitting / receiving data using the selected communication channel. 2. The data communication apparatus according to claim 1, wherein the selection unit selects the channel so as to eliminate the bias of the communication channel being used. The data communication apparatus according to claim 1, wherein the selection unit selects a communication channel that is not used. 4. The data communication apparatus according to claim 1, wherein the determination unit reflects an influence on a neighboring communication channel by using each communication channel in a use situation. The data according to any one of claims 1 to 4, wherein the determination means determines a use situation according to the number of access points using the communication channel for each communication channel. Communication device. 6. The data communication apparatus according to claim 5, wherein the determination unit determines the number of access points based on a beacon transmitted from an access point using each communication channel. The determination means gives the largest weight to the number of access points to the communication channel being used, and gives the weight to the number of access points that decreases in size as the communication channel moves away from the center. The data communication apparatus according to claim 1, wherein the situation is reflected. 8. The determination unit according to claim 7, wherein the determination means gives 6 to the communication channel being used as the weighting, and sequentially gives a weight of 3: 2: 1 every time one communication channel leaves. Data communication device. 9. The data communication apparatus according to claim 1, wherein the selection unit selects a communication channel by avoiding a communication method having a low communication speed when there are a plurality of communication methods. The said determination means determines the use condition of the said communication channel for every predetermined time, The said selection means changes a communication channel based on the use condition, The said any one of the Claims 1-9 characterized by the above-mentioned. The data communication apparatus according to 1. 11. The data communication apparatus according to claim 10, wherein the upper communication channel is not changed when the wireless terminal is communicating with the data communication apparatus. A data communication device for transmitting and receiving data through any one of the communication channels selected from a plurality of communication channels assigned a predetermined frequency band,
A determination means for determining a use situation for each communication channel;
A selection means for selecting a communication channel suitable for use based on a predetermined condition based on the use situation;
A data communication apparatus comprising: transmission / reception means for transmitting / receiving data using the selected communication channel. A data communication method in which any one of a plurality of communication channels to which a predetermined frequency band is assigned is used, and a plurality of individual wireless terminals wirelessly transmit and receive data to a common access point. And
A determination step of determining the use status for each communication channel;
A selection step of selecting a communication channel suitable for use based on a predetermined condition based on the same usage situation;
A data transmission method comprising: a transmission / reception step of transmitting / receiving data using the selected communication channel. A data communication program in which a plurality of individual wireless terminals wirelessly transmit and receive data to and from a common access point using any one of a plurality of communication channels assigned a predetermined frequency band. And
A determination function for determining the usage status for each communication channel;
A selection function for selecting a communication channel suitable for use based on a predetermined condition based on the same usage situation;
A data communication program for causing a computer to realize a transmission / reception function for transmitting / receiving data using the selected communication channel. Communication channel selection for selecting a communication channel to be used from a plurality of communication channels assigned a predetermined frequency band when a plurality of individual wireless terminals wirelessly transmit and receive data to a common access point A device,
A determination means for determining a use situation for each communication channel;
A communication channel selection device comprising: selection means for selecting a communication channel suitable for use based on a predetermined condition based on the use status. Communication channel selection for selecting a communication channel to be used from a plurality of communication channels assigned a predetermined frequency band when a plurality of individual wireless terminals wirelessly transmit and receive data to a common access point A program,
A determination function for determining the usage status for each communication channel;
A communication channel selection program for causing a computer to realize a selection function for selecting a communication channel suitable for use based on a predetermined condition based on the use situation.

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