JP5261512B2 - Communication device, wireless LAN access point, channel selection method, and channel selection program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a communication device which can select a frequency or a channel based on the determination whether or not a beacon can be transmitted, and to provide a wireless LAN access point, a channel selection method and a channel selection program. <P>SOLUTION: A beacon transmission means 12 tries transmission of a beacon on the channel of a frequency selected by a frequency selection means 11, tries transmission again when the transmission has failed at the stage of carrier sense, determines the number of times the transmission has failed, and then selects the channel where the number of times the transmission has failed is lowest as a transmission channel. The channel may be selected while taking account of the comparison of the number of times of receiving other beacons within a predetermined time among the channels. <P>COPYRIGHT: (C)2012,JPO&amp;INPIT

Description

  The present invention relates to a communication device, a wireless LAN access point, a channel selection method, and a channel selection program, and particularly to a communication device, a wireless LAN access point, a channel selection method, and a channel selection program for ensuring good communication.

  Various wireless terminals such as personal computers having a communication function are often connected to each other or connected to other networks using a wireless local area network (LAN) access point. Since the wireless LAN access point can be freely installed in each place such as a home, there is a possibility that a problem of radio wave interference with other wireless LAN access points and various electric products may occur.

  Therefore, a person using a wireless LAN access point can manually select a frequency to be used from a plurality of channels so as not to overlap with surrounding channels or frequencies using a communication terminal such as a personal computer to be used. . Depending on the wireless LAN access point, such channel setting can be automatically performed.

  In the first related technology related to the present invention, the interference amount is calculated by observing beacon signals transmitted by other wireless LAN devices for all channels that can be used by the wireless LAN access point for communication. (See, for example, Patent Document 1). In the first related technique, an empty channel determined as a result of calculation is automatically set in the wireless LAN access point.

  In the second related technique related to the present invention, interference wave power is detected for each channel to be selected (see, for example, Patent Document 2). In the second related technique, a channel having the smallest interference wave power is selected.

  Furthermore, in a third related technique related to the present invention, a management server is connected to a wireless LAN access point by a wired line, and a channel of the wireless LAN access point is set using this management server (for example, patents). Reference 3). For this reason, the management server performs channel assignment calculation based on the number of wireless LAN base stations and their electric field strengths based on the preset proximity wireless LAN base station information table so that interference does not occur, The station is notified.

  Among these, in the third related technology, the management server calculates and notifies whether radio wave interference occurs in the wireless LAN access point to be investigated based on information of the wireless LAN base station whose position is known in advance. . Therefore, it is not possible to take interference countermeasures in consideration of radio wave generation sources other than the wireless LAN base station.

  In the first related technique, the amount of interference is calculated by observing the beacon signal transmitted by the wireless LAN device. Therefore, when the first related technology is used, a countermeasure against interference can be taken for a wireless LAN device that transmits a beacon signal, but any countermeasure is taken against radiation noise of a general electronic device such as a microwave oven. I can't.

  Therefore, the second related technology is expected. However, in the second related technology, the level of the interference power is obtained by averaging the received power of each channel over time. Therefore, the time-averaged interference power is not only affected by the radiation noise of general electronic equipment but also the influence of signals from other access points, which makes it difficult to grasp the actual situation. That is, in the related art, when a communication device such as a wireless LAN access point is installed, there is a problem that it is difficult for the own device to determine whether actual communication is possible by sending out a beacon.

  Thus, as a fourth related technique, it has been proposed to receive and count beacons transmitted by other stations and transmit beacons based on the results (see, for example, Patent Document 4).

JP 2002-158667 A (paragraph 0040, paragraph 0041, FIG. 6) JP 2002-186019 (paragraphs 0020 and 0023, FIG. 2) JP 2006-025003 A (paragraph 0018, paragraph 0029, Table 4) Table No. 2008/053519 (paragraph 0047, FIG. 10)

  According to the fourth related technique, beacons transmitted from other stations are received, the number thereof is counted up, and the count value obtained thereby is compared with a predetermined threshold value. When the count value is equal to or greater than the threshold value, the transmission timing of the beacon transmitted by the own station is adjusted so as not to overlap with the reception timing of these beacons that are periodically received.

  However, in the fourth related technique, as described above, it is impossible to determine the influence of radiation noise of various electronic devices that do not transmit beacons. Therefore, even if an attempt is made to transmit a beacon whose transmission timing is adjusted after setting a frequency or channel for communication, there is a possibility that a beacon cannot be transmitted for a nearby electronic device.

  As mentioned above, the problem of the channel selection of the communication device using the conventional beacon using the wireless LAN access point has been described, but the transmission of the general communication device using the beacon is also performed when the frequency or channel is selected. There is a similar problem.

  Accordingly, an object of the present invention is to provide a communication device, a wireless LAN access point, a channel selection method, and a channel selection program that can select a frequency or a channel based on whether or not a beacon can be transmitted.

  In the present invention, (a) frequency selection means for sequentially selecting the center frequencies of a plurality of predetermined channels one by one, and (b) a beacon as a radio beacon using the center frequency selected by the frequency selection means. A beacon transmission means that repeatedly transmits a survey period as a predetermined period within a predetermined situation investigation time as a time per channel, and (c) when this beacon transmission means starts transmitting a beacon. Before detecting the reception power level of the carrier frequency, if this reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure, but only when the received power level is lower than the predetermined threshold. Carrier sense means, and (d) when the beacon transmission of the above-described beacon transmission means fails by this carrier sense means, (E) a beacon transmission control unit that repeatedly attempts transmission by this beacon transmission unit at a failure period as a predetermined period if it is within the above-described situation investigation time until the transmission of the kon is successful, and (e) the beacon transmission control unit A transmission failure counting means for counting the number of times a beacon transmission has failed continuously when transmission is attempted, for each beacon using the channel of the center frequency selected by the frequency selection means, and (to) this transmission failure. The count value of the counting means is compared with the plurality of channels selected by the frequency selecting means, and the channel of the center frequency with the lowest number of beacon transmission failures by the beacon transmitting means is selected as the communication channel. The communication device includes channel selection means for performing the above operation.

  In the present invention, (b) frequency selection means for sequentially selecting each of the center frequencies of a plurality of predetermined channels one by one, and (b) a radio beacon using the center frequency selected by the frequency selection means A beacon transmitting means for repeatedly transmitting a beacon of a predetermined period as a time per channel within a predetermined period of investigation time, and (c) when the beacon transmitting means starts transmitting a beacon. Prior to this, when the received power level of the carrier frequency is sensed and the received power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure, and the beacon is transmitted only when the received power level is lower than the predetermined threshold. And (d) the beacon transmission of the beacon transmission means described above has failed by the carrier sense means. A beacon transmission control unit that repeatedly attempts transmission by this beacon transmission unit at a failure period as a predetermined period until the beacon transmission is successful, and (e) this beacon transmission control. A transmission failure counting means for counting, for each beacon using the channel of the center frequency selected by the frequency selection means, the number of times that the beacon transmission has failed continuously when transmission is attempted by the means; A beacon receiving means for receiving a beacon transmitted by a surrounding access point at a predetermined access point detection time prior to the start of each of the situation check times, and (g) the beacon receiving means within the access point detection time described above. The number of beacons received at the center frequency selected by the frequency selection means described above Receiving beacon counting means for counting each beacon using a channel; and (h) the plurality of channels selected by the frequency selecting means with the count value of the receiving beacon counting means and the count value of the transmission failure counting means described above. And a channel selection means for selecting a channel having a center frequency with the lowest number of beacon transmissions by the beacon transmission means and the lowest count value of the received beacon count means as a communication channel. A LAN access point is provided.

  Further, in the present invention, (b) a frequency selection step for sequentially selecting the center frequencies of a plurality of predetermined channels one by one, and (b) a radio beacon using the center frequency selected in the frequency selection step. A beacon transmission step of repeatedly transmitting a beacon as a time per channel within a predetermined period of time in a state investigation time, and (c) starting beacon transmission in this beacon transmission step; Prior to this, when the received power level of the carrier frequency is sensed and the received power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure, and the beacon is transmitted only when the received power level is lower than the predetermined threshold. A carrier sense step to be performed; and When the beacon transmission of the beacon fails, a beacon transmission control step that repeatedly attempts transmission by this beacon transmission step at a failure period as a predetermined period until the beacon transmission is successful until the beacon transmission is successful. (E) A transmission failure count that counts, for each beacon using the channel of the center frequency selected in the frequency selection step, the number of times the beacon transmission has failed continuously when transmission is attempted in this beacon transmission control step. And (b) the center frequency at which the number of failed beacon transmissions in the beacon transmission step is the lowest by comparing the count value in the transmission failure count step with the plurality of channels selected in the frequency selection step. Select a channel for communication Yaneru selection step and a channel selection method is provided.

  Furthermore, in the present invention, (b) a frequency selection step for sequentially selecting the center frequencies of a plurality of predetermined channels one by one, and (b) a radio beacon using the center frequency selected in the frequency selection step. A beacon transmission step for repeatedly transmitting a beacon as a time per channel within a predetermined period of time for investigation within a predetermined period of time for investigation, and (c) starting beacon transmission at this beacon transmission step. Prior to this, when the received power level of the carrier frequency is sensed and the received power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure and only when the beacon is less than the predetermined threshold. A carrier sense step for transmission, and (d) the beacon transmission step described above by this carrier sense step. Beacon transmission control that repeatedly attempts transmission in this beacon transmission step with a predetermined period if it is within the above-described situation investigation time until beacon transmission is successful And (e) counting the number of times beacon transmission has failed continuously when transmission is attempted in this beacon transmission control step for each beacon using the channel of the center frequency selected in the frequency selection step described above. A transmission failure counting step; (f) a beacon receiving step for receiving a beacon transmitted by a surrounding access point at a predetermined access point detection time prior to the start of each of the above-described situation investigation times; and (g) this beacon. Receive within the access point detection time described above in the reception step. A reception beacon count step for counting the number of beacons for each beacon using the channel of the center frequency selected in the frequency selection step, and (h) a count value in the reception beacon count step and the transmission failure count step. The count value of the received beacon count step is the lowest and the count value in the received beacon count step is the lowest. The channel selection method includes a channel selection step of selecting a channel having a center frequency as a communication channel.

  Further, according to the present invention, (b) a frequency selection process for sequentially selecting the center frequencies of a plurality of predetermined channels one by one as a channel selection program in the computer of the communication apparatus; A beacon transmission process for repeatedly transmitting a beacon as a radio beacon using the center frequency selected in step 1 as a time per channel within a predetermined period of time for investigation within a predetermined period of investigation, and (c) this When the beacon transmission is started in the beacon transmission process, the reception power level of the carrier frequency is sensed prior to this, and when the reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure. Carrier sense processing that transmits a beacon only when it is less than the threshold value, and (d) When the beacon transmission in the above-described beacon transmission process fails, the transmission by this beacon transmission process is repeated at a failure time period as a predetermined period until the beacon transmission is successful until the beacon transmission is successful. Beacon transmission control process to be attempted, and (e) a beacon using the channel of the center frequency selected in the frequency selection process described above, the number of times the beacon transmission has failed continuously when transmission is attempted by this beacon transmission control process Transmission failure count processing that counts every time, and (f) failure of beacon transmission by the above-described beacon transmission processing by comparing the count value by this transmission failure counting processing with the plurality of channels selected by the above-described frequency selection processing The channel with the lowest center frequency is selected as the communication channel. Characterized in that to execute the Le selection process.

  Further, according to the present invention, as a channel selection program, (b) frequency selection processing for sequentially selecting the center frequencies of a plurality of predetermined channels one by one as a channel selection program; A beacon transmission process for repeatedly transmitting a beacon as a radio beacon using the center frequency selected in the selection process as a time per channel within a predetermined period of time within a predetermined period of a period of investigation as a period of investigation. ) When starting the transmission of a beacon in this beacon transmission process, the reception power level of the carrier frequency is sensed prior to this, and if this reception power level exceeds a predetermined threshold value, the beacon is not transmitted as a failure. Carrier sense processing that transmits a beacon only when it is less than a predetermined threshold, and (d) this key. When the beacon transmission in the above-described beacon transmission process fails due to the sense process, the transmission by this beacon transmission process is performed at a failure period as a predetermined period within the above-described situation investigation time until the beacon transmission is successful. The beacon transmission control process to be repeatedly tried, and (e) the channel of the center frequency selected in the frequency selection process described above is the number of times the beacon transmission has failed continuously when transmission is attempted by this beacon transmission control process. A transmission failure count process that counts for each beacon; and (be) a beacon reception process that receives a beacon transmitted by a surrounding access point at a predetermined access point detection time prior to the start of each of the above-described situation investigation times; (G) When an access point is detected in this beacon reception process A reception beacon count process for counting the number of beacons received in each beacon using the channel of the center frequency selected in the frequency selection process, and (h) a count value in the reception beacon count process and the transmission described above The count in the received beacon count process is the minimum number of times the beacon transmission has failed in the beacon transmission process by comparing the count value in the failure count process with the plurality of channels selected in the frequency selection process. Channel selection processing for selecting a channel having the lowest center frequency as a communication channel is performed.

  As described above, according to the present invention, the center frequencies of a plurality of predetermined channels are sequentially selected one by one, and transmission of a beacon of the selected channel is attempted. When beacon transmission could not be performed due to carrier sense, beacon transmission was attempted and the number of failed transmissions was determined, and based on this, the communication environment for each channel was determined. As a result, it is possible to determine the actual transmission environment including the radiated wave noise around the communication device or the wireless LAN access point and perform appropriate channel setting.

  Further, according to the present invention, since the number of failed beacon transmissions described above is obtained and the beacons of other wireless LAN access points are grasped for each channel, the actual transmission environment around the wireless LAN access points Can be discriminated better, and appropriate channel setting can be performed.

It is a claim corresponding | compatible figure of the communication apparatus of this invention. It is a claim corresponding figure of the wireless LAN access point of this invention. It is a claim corresponding | compatible figure of the channel selection method of this invention. It is a claim corresponding | compatible figure of the other channel selection method of this invention. It is a claim correspondence diagram of the channel selection program of the present invention. It is a claim corresponding | compatible figure of the other channel selection program of this invention. It is a block diagram showing the structure of the wireless LAN access point in embodiment of this invention. It is the flowchart which showed the outline | summary of the flow of the channel selection process in which a wireless LAN access point selects the best channel. It is explanatory drawing which showed each channel which the wireless LAN access point of this Embodiment can set, and its center frequency. FIG. 9 is a flowchart showing specific contents of processing for checking whether or not a beacon of another wireless LAN access point in the vicinity of the wireless access point is detected as processing in step S203 of FIG. It is a flowchart showing the specific content of the process of the situation investigation by beacon transmission in step S204 of FIG. It is the timing figure which showed an example of the beacon detection of each channel investigated in this Embodiment, and a beacon transmission result. FIG. 4 is an arrangement explanatory diagram showing an example of an arrangement relationship between a wireless LAN access point that performs channel selection discrimination, another wireless LAN access point, and another wireless LAN access point, etc. according to the present embodiment. It is the arrangement explanatory view showing other arrangement relations of the wireless LAN access point and other wireless LAN access point and the microwave oven in the present embodiment. It is the timing figure which showed an example of the beacon detection and beacon transmission result in the Xth channel in the arrangement | positioning condition shown in FIG. 14 of this Embodiment. It is a flowchart showing the mode of the process which selects the channel of the best evaluation result in the wireless LAN channel control part of this Embodiment. 5 is a flowchart specifically showing an example of evaluation comparison processing between two channels according to the present embodiment. It is a block diagram showing the structure of the wireless LAN access point in the modification of this invention. It is explanatory drawing which showed each channel which those wireless LAN access points of the modification in this modification can set, and those center frequencies.

  FIG. 1 is a diagram corresponding to the claims of the communication apparatus of the present invention. The communication device 10 of the present invention includes a frequency selection unit 11, a beacon transmission unit 12, a carrier sense unit 13, a beacon transmission control unit 14, a transmission failure count unit 15, and a channel selection unit 16. Here, the frequency selection unit 11 sequentially selects the center frequencies of a plurality of predetermined channels one by one. The beacon transmission unit 12 repeatedly transmits a beacon using the channel of the center frequency selected by the frequency selection unit 11 at a survey cycle as a predetermined cycle within a predetermined status survey time as a time per channel. When the beacon transmission unit 12 starts transmitting a beacon, the carrier sense unit 13 senses the reception power level of the carrier frequency prior to this, and when the reception power level is equal to or higher than a predetermined threshold, A beacon is transmitted only when the transmission is not performed and the threshold value is below the predetermined threshold. When the beacon transmission of the beacon transmission unit 12 fails by the carrier sense unit 13, the beacon transmission control unit 14 is a failure cycle as a predetermined cycle if the beacon transmission is successful until the beacon transmission is successful. The transmission by the beacon transmission means 12 is repeatedly attempted. The transmission failure counting unit 15 counts the number of times that the beacon transmission has failed continuously when the transmission is attempted by the beacon transmission control unit 14 for each beacon using the channel of the center frequency selected by the frequency selection unit 11. . The channel selection unit 16 compares the count value of the transmission failure count unit 15 with the plurality of channels selected by the frequency selection unit 11 and the channel of the center frequency with the lowest number of beacon transmissions by the beacon transmission unit 12 Is selected as the communication channel.

  FIG. 2 shows a claim correspondence diagram of the wireless LAN access point of the present invention. The wireless LAN access point 20 of the present invention includes a frequency selection unit 21, a beacon transmission unit 22, a carrier sense unit 23, a beacon transmission control unit 24, a transmission failure count unit 25, a beacon reception unit 26, and a reception beacon. Counting means 27 and channel selecting means 28 are provided. Here, the frequency selection means 21 selects the center frequencies of a plurality of predetermined channels one by one in order. The beacon transmission unit 22 repeatedly transmits a beacon using the channel of the center frequency selected by the frequency selection unit 21 at a survey cycle as a predetermined cycle within a predetermined status survey time as a time per channel. When the beacon transmission unit 22 starts transmitting a beacon, the carrier sense unit 23 senses the reception power level of the carrier frequency prior to this, and when this reception power level is equal to or higher than a predetermined threshold, A beacon is transmitted only when the transmission is not performed and the threshold value is below the predetermined threshold. When the beacon transmission of the beacon transmission unit 22 is failed by the carrier sense unit 23, the beacon transmission control unit 24 is a failure cycle as a predetermined cycle within the above-described situation investigation time until the beacon transmission is successful. The transmission by the beacon transmission means 22 is repeatedly attempted. The transmission failure counting means 25 counts the number of times that beacon transmission has failed continuously when transmission is attempted by the beacon transmission control means 24 for each beacon using the channel of the center frequency selected by the frequency selection means 21. . The beacon receiving means 26 receives a beacon transmitted by a surrounding access point at a predetermined access point detection time prior to the start of each of the above-described situation investigation times. The reception beacon counting unit 27 counts the number of beacons received by the beacon receiving unit 26 within the access point detection time described above for each beacon using the channel of the center frequency selected by the frequency selection unit 21. The channel selection means 28 compares the count value of the reception beacon count means 27 and the count value of the transmission failure count means 25 with the plurality of channels selected by the frequency selection means 21, and the beacon transmission means 22 fails to transmit the beacon. The channel with the lowest center frequency and the lowest count value of the reception beacon counting means 27 is selected as the communication channel.

  FIG. 3 is a diagram corresponding to claims of the channel selection method of the present invention. The channel selection method 30 of the present invention includes a frequency selection step 31, a beacon transmission step 32, a carrier sense step 33, a beacon transmission control step 34, a transmission failure count step 35, and a channel selection step 36. Here, in the frequency selection step 31, the center frequencies of a plurality of predetermined channels are sequentially selected one by one. In the beacon transmission step 32, a beacon using the channel of the center frequency selected in the frequency selection step 31 is repeatedly transmitted at a survey cycle as a predetermined cycle within a predetermined status survey time as a time per channel. In the carrier sense step 33, when the beacon transmission is started in the beacon transmission step 32, the reception power level of the carrier frequency is sensed prior to this, and if this reception power level is equal to or higher than a predetermined threshold, the beacon is determined as a failure. A beacon is transmitted only when the transmission is not performed and the threshold value is below the predetermined threshold. In the beacon transmission control step 34, when the beacon transmission in the beacon transmission step 32 fails in the carrier sense step 33, the failure occurs as a predetermined period within the above-described situation investigation time until the beacon transmission is successful. The transmission by the beacon transmission step 32 is repeatedly attempted at a period. In the transmission failure counting step 35, the number of times the beacon transmission has failed continuously when the transmission is attempted by the beacon transmission control step 34 is counted for each beacon using the channel of the center frequency selected in the frequency selection step 31. . In channel selection step 36, the count value in transmission failure count step 35 is compared with the plurality of channels selected in frequency selection step 31, and the center frequency with the lowest number of beacon transmission failures in beacon transmission step 32 is communicated. Select the channel as the frequency for use.

  FIG. 4 is a diagram corresponding to claims of another channel selection method of the present invention. Another channel selection method 40 of the present invention includes a frequency selection step 41, a beacon transmission step 42, a carrier sense step 43, a beacon transmission control step 44, a transmission failure count step 45, a beacon reception step 46, a reception A beacon counting step 47 and a channel selection step 48 are provided. Here, in the frequency selection step 41, the center frequencies of a plurality of predetermined channels are sequentially selected one by one. In the beacon transmission step 42, a beacon using the channel of the center frequency selected in the frequency selection step 41 is repeatedly transmitted in a survey cycle as a predetermined cycle within a predetermined status survey time as a time per channel. In the carrier sense step 43, when the beacon transmission is started in the beacon transmission step 42, the reception power level of the carrier frequency is sensed prior to this, and if this reception power level is equal to or higher than a predetermined threshold value, the beacon is regarded as a failure. A beacon is transmitted only when the transmission is not performed and the threshold value is below the predetermined threshold. In the beacon transmission control step 44, when the beacon transmission in the beacon transmission step 42 fails in the carrier sense step 43, a failure period as a predetermined period is within the above-described situation investigation time until the beacon transmission is successful. The transmission by the beacon transmission step 42 is repeatedly attempted. In the transmission failure counting step 45, the number of times that the beacon transmission continuously fails when transmission is attempted by the beacon transmission control step 44 is counted for each beacon using the channel of the center frequency selected in the frequency selection step 41. . In the beacon receiving step 46, beacons transmitted by neighboring access points are received at a predetermined access point detection time prior to the start of each of the situation check times. In the reception beacon count step 47, the number of beacons received within the access point detection time described in the beacon reception step 46 is counted for each beacon using the channel of the center frequency selected in the frequency selection step 41. In the channel selection step 48, the count value in the reception beacon count step 47 and the count value in the transmission failure count step 45 are compared with the plurality of channels selected in the frequency selection step 41, and the beacon transmission in the beacon transmission step 42 is performed. The channel with the lowest center frequency and the lowest count value in the received beacon counting step 47 is selected as the communication channel.

  FIG. 5 shows a claim correspondence diagram of the channel selection program of the present invention. The channel selection program 50 according to the present invention includes a frequency selection process 51, a beacon transmission process 52, a carrier sense process 53, a beacon transmission control process 54, a transmission failure count process 55, and a channel selection process. 56 is executed. Here, in the frequency selection processing 51, the center frequencies of a plurality of predetermined channels are sequentially selected one by one. In the beacon transmission process 52, a beacon using the channel of the center frequency selected in the frequency selection process 51 is repeatedly transmitted in a survey period as a predetermined period within a predetermined condition survey time as a time per channel. In carrier sense processing 53, when beacon transmission processing 52 starts beacon transmission, the reception power level of the carrier frequency is sensed prior to this, and if this reception power level is equal to or greater than a predetermined threshold value, the beacon transmission is determined as a failure. A beacon is transmitted only when the transmission is not performed and the threshold value is below the predetermined threshold. In the beacon transmission control process and 54, when the beacon transmission of the beacon transmission process 52 fails by the carrier sense process 53, if it is within the above-described situation investigation time until the beacon transmission is successful, the failure as a predetermined period The transmission by the beacon transmission process 52 is repeatedly attempted at a period. In the transmission failure count process 55, the number of times that the beacon transmission has failed continuously when the transmission is attempted by the beacon transmission control process 54 is counted for each beacon using the channel of the center frequency selected in the frequency selection process described above. To do. In the channel selection process 56, the count value obtained by the transmission failure count process 55 is compared with the plurality of channels selected in the frequency selection process 51, and the center frequency with the lowest number of beacon transmission failures by the beacon transmission process 52 is communicated. Select channel as frequency for use.

  FIG. 6 shows a claim correspondence diagram of another channel selection program of the present invention. Another channel selection program 60 according to the present invention is provided in a wireless LAN access point computer to a frequency selection process 61, a beacon transmission process 62, a carrier sense process 63, a beacon transmission control process 64, and a transmission failure count process 65. The beacon reception process 66, the received beacon count process 67, and the channel selection process 68 are executed. Here, in the frequency selection processing 61, the center frequencies of a plurality of predetermined channels are sequentially selected one by one. In the beacon transmission process 62, a beacon using the channel of the center frequency selected in the frequency selection process 61 is repeatedly transmitted at a survey cycle as a predetermined cycle within a predetermined status survey time as a time per channel. In carrier sense processing 63, when beacon transmission is started in beacon transmission processing 62, the reception power level of the carrier frequency is sensed prior to this, and if this reception power level is equal to or higher than a predetermined threshold, the beacon is regarded as a failure. A beacon is transmitted only when the transmission is not performed and the threshold value is below the predetermined threshold. In the beacon transmission control process 64, when the beacon transmission of the beacon transmission process 62 fails by the carrier sense process 63, the failure period as a predetermined period is within the above-described situation investigation time until the beacon transmission is successful. The transmission by the beacon transmission process 62 is repeatedly attempted. In the transmission failure counting process 65, the number of times that the beacon transmission has failed continuously when the transmission is attempted by the beacon transmission control process 64 is counted for each beacon using the channel of the center frequency selected in the frequency selection process 61. . In the beacon reception process 66, beacons transmitted by surrounding access points are received at a predetermined access point detection time prior to the start of each of the situation check times. In the received beacon count process 67, the number of beacons received within the access point detection time described above in the beacon reception process 66 is counted for each beacon using the channel of the center frequency selected in the frequency selection process 61. In the channel selection processing 68, the count value in the reception beacon count processing 67 and the count value in the transmission failure count processing 65 are compared with the plurality of channels selected in the frequency selection processing 61, and the beacon transmission by the beacon transmission processing 62 is performed. The channel with the lowest center frequency and the lowest count value in the received beacon count processing 67 is selected as the communication channel.

  <Embodiment of the Invention>

  Next, an embodiment of the present invention will be described.

  FIG. 7 shows a configuration of a wireless LAN access point according to the embodiment of the present invention. The wireless LAN access point 100 is a radio wave relay device that connects each communication terminal using a wireless LAN (Local Area Network).

  Such a wireless LAN access point 100 includes a CPU (Central Processing Unit) 101 serving as the center of various controls. The CPU 101 is connected to the following units via a bus 102 such as a data bus. However, at least a part of these units does not need to be realized by hardware, and may be realized as a software function unit by the CPU 101 executing a control program stored in the memory 103.

  The wireless LAN transmission unit 104 is a circuit part that transmits a beacon after performing carrier sense for each channel within a usable frequency range. Here, carrier sense refers to sensing the reception power level of the carrier frequency, and if this is greater than or equal to a predetermined threshold value, communication is not performed, and if it is less than the threshold value, communication is performed. A beacon is a radio beacon.

  The wireless LAN receiving unit 105 is a circuit part that receives a beacon transmitted by a surrounding access point for each channel within a usable channel range in a wireless frequency. The wireless LAN channel control unit 106 is a circuit part that selects the best channel suitable for the surrounding communication environment, as will be described in detail later. In the present embodiment, the wireless LAN access point 100 transmits a beacon for each channel, sequentially compares the results, and obtains the channel that provides the best result. The selected channel storage unit 107 is a circuit part that stores a channel selected as the best channel.

  The reception beacon counter 108 is a counter circuit that counts received beacons. The beacon reception control unit 109 is a circuit part that calculates the channel usage based on the count result of the reception beacon counter 108. The transmission beacon counter 110 is a circuit portion that counts the number of times that transmission could not be performed continuously when attempting to transmit a designated number of beacons. The beacon transmission control unit 111 performs control for recording the beacon transmission failure degree for the corresponding channel based on the count result of the transmission beacon counter 110 and designating the next channel.

  FIG. 8 shows an outline of the flow of channel selection processing in which the wireless LAN access point configured as described above selects the best channel. This will be described with reference to FIG.

  The CPU 101 of the wireless LAN access point 100 waits for a predetermined start trigger to be generated such that a power switch (not shown) is turned on by software (step S201). When a start trigger occurs (Y), the wireless LAN channel control unit 106 first sets an initial value for a channel to be selected (step S202).

  FIG. 9 shows each channel that can be set by the wireless LAN access point of the present embodiment and its center frequency. The wireless LAN access point 100 can select 13 channels from a first channel having a center frequency of 2412 MHz (megahertz) to a 13th channel having a center frequency of 2472 MHz. In this case, the wireless LAN channel control unit 106 selects the first channel whose center frequency is 2412 MHz, for example, as an initial value. Such a list of frequencies of each channel is stored in a nonvolatile specific area of the memory 103.

  The wireless LAN receiving unit 105 checks whether a beacon having the same frequency as that of the selected first channel is detected from the periphery of the wireless LAN access point 100 (step S203). It is assumed that there are other wireless LAN access points around the wireless LAN access point 100 of the present embodiment. In this case, the wireless LAN access point 100 should be used depending on whether or not the “other wireless LAN access point” (hereinafter referred to as another wireless LAN access point) transmits a beacon having the same frequency as the first channel. This is because the channel is affected.

  FIG. 10 shows the specific contents of the process for checking whether or not a beacon of another wireless LAN access point in the vicinity of the wireless access point is detected as the process in step S203 of FIG. This will be described with reference to FIG.

  The wireless LAN reception unit 105 sets a target channel to be received, and resets the count value of the target channel in the reception beacon counter 108 to “0” (step S221). In this example, the first channel having a center frequency of 2412 MHz is set as the target channel as an initial value, and the count value of the first channel of the reception beacon counter 108 is reset to “0”. In this state, the wireless LAN receiving unit 105 determines whether a beacon having the frequency of the first channel has been received within a predetermined unit time (step S222).

  At this time, if a beacon is received (step S222: Y), "1" is counted up as the number of beacons received from other wireless LAN access points other than the wireless LAN access point 100 being detected (step S222). S223). That is, the count value of the first channel of the reception beacon counter 108 is counted up from “0” to “1”.

When the above processing is completed, the wireless LAN receiving unit 105 determines whether a predetermined time T ₁ for detection has elapsed (step S224). If the time T ₁ has not elapsed (N), the process returns to step S222 to determine whether or not reception of a beacon of the frequency of the first channel is performed within the unit time described above. At this time, if the beacon of the frequency of the first channel is not received (N), the process of step S224 is performed without counting up the count value of the first channel of the reception beacon counter 108. When a beacon having a frequency of the first channel is received within the unit time (step S222: Y), the count value of the first channel of the reception beacon counter 108 is further incremented by “1” (step S223). ).

Measurement is continued in this way. If the wireless LAN receiving unit 105 determines in step S224 that the time T ₁ has elapsed from the start of detection (Y), the process shown in FIG. 10 for the corresponding channel ends (end).

  Returning to the description of the processing in FIG. When the beacon detection process for the frequency of the first channel in step S203 is completed, the wireless LAN access point 100 as its own device transmits a beacon and investigates the situation on the transmitting side (step S204).

  FIG. 11 shows the specific contents of the situation investigation processing by beacon transmission in step S204 of FIG. This will be described with reference to FIG.

  First, the wireless LAN transmission unit 104 sets the same target channel as the channel set in step S221 in FIG. 10 as a transmission channel, and resets the count value of the target channel in the transmission beacon counter 110 to “0” (step S241). ). Next, the wireless LAN transmission unit 104 performs carrier sense (step S242) and determines whether beacon transmission is possible (step S243). If it is found that another device is transmitting a signal to the same channel at the carrier sense stage of step S242, a beacon cannot be transmitted. Specifically, when the transmission of a beacon is started, the reception power level of the carrier frequency is sensed prior to this, and when this reception power level is equal to or higher than a predetermined threshold value, the beacon is not transmitted as a failure. A beacon can be transmitted only when the reception power level of the carrier frequency is less than the predetermined threshold.

When it is determined in step S243 that beacon transmission is possible (Y), the wireless LAN transmission unit 104 transmits a beacon (step S244). Then, waiting until the time T ₂ of the until the start of the transmission of the next beacon is passed (step S245), after a lapse of time T ₂ (Y), advance or set time T ₃ has elapsed for investigation Is discriminated (step S246). If the time T ₃ has not elapsed (N), the process returns to step S242 to perform carrier sense. Thereafter, the same processing is performed.

As a result of performing carrier sense in this way, it is determined that other devices are transmitting signals to the same channel before the time T ₃ elapses, and it is determined that beacon transmission is not possible (step S243: N). In this case, the wireless LAN transmission unit 104 determines whether beacon transmission is continuously impossible (step S247).

As a result, if beacon transmission is not performed (transmission failed) even in the previous carrier sense, that is, if beacon transmission is not possible continuously (step S247: Y), wireless The LAN transmission unit 104 increments the count value of the transmission beacon counter 110 by “1”. In this case, a time T ₄ different from the time T ₂ determined in step S245 is newly set, and the process waits until the time T ₄ elapses (step S249). Time T ₄ is shorter than time T ₂ . When the time T ₄ has elapsed (Y), the process proceeds to step S246. In this way, transmission of beacons is attempted by changing the time interval in which carrier sense is performed.

On the other hand, when it is determined that another device is not transmitting a signal to the same channel at the previous carrier sense (step S247: N), the count value of the transmission beacon counter 110 is set to “1”. (Step S250). The same time T ₂ and which determine the time T ₂ at step S245 and waits until elapse (step S251). In this case, when the time T ₂ has elapsed (Y), the process proceeds to step S246.

Assume that it is determined that the time T ₃ has elapsed from the start of the investigation when the processing as described above is performed and the processing shifts to step S246 (step S246: Y). When the time T ₃ has elapsed, the status survey for the corresponding channel is completed (END).

  Returning to the description of the processing in FIG. When the situation investigation by beacon transmission in step S204 is completed, the target channel is evaluated (step S205). This will be described later together.

  When the target channel is evaluated in step S205, it is determined whether the measurement and evaluation of all the channels have been completed by completing the processing of the target channel (step S206). If the processing for the first channel has been completed, the processing up to the thirteenth channel has not been completed as shown in FIG. 9 (N). Therefore, in this case, the target channel is advanced to the next second channel (step S207), and the process proceeds to step S203.

  When the processing of all channels is completed as a result of the processing of step S203 to step S205 being sequentially performed for each channel in this way (step S206: Y), the channel with the best evaluation is selected (step S208), and wireless The process of selecting the best channel by the LAN access point 100 ends (END).

FIG. 12 shows an example of beacon detection and beacon transmission results for each channel investigated as described above. FIG 12, a detection section T _A of the other wireless LAN access points for each of the first to thirteenth channels performed in step S203 of FIG. 8, survey period T _B is illustrated by the transmission of a beacon. Where the length of the survey interval T _B is equal to the time T ₃ described in FIG. 11. This will be described with reference to FIGS. 7 and 11.

For example, in the first channel, the other wireless LAN access points other wireless LAN access point detection section T _A of for the peripheral access point detection is not detected. In survey period T _B, at intervals of time described T ₂ at step S245 of FIG. 11, transmission of a beacon from the wireless LAN access point 100 are performed, and also succeeded either transmission.

In the second channel, the other wireless LAN access points as in the first channel detection section T _A of the other wireless LAN access point is not detected. For transmission of a beacon from the wireless LAN access point 100 in the context survey interval T _B, total failure is caused which is transmitting a signal to other devices with the same channel at the carrier sense phase of step S242 (NG: no good, FAIL). Here, the transmission interval between the first and second beacon transmissions is time T ₂ , but the second and subsequent transmissions continue to fail. Therefore, the beacon transmission interval is shortened to the time T ₄ described in step S249 in FIG.

In the third channel, the detection of other wireless LAN access points has been performed by the detection section T _A of the other wireless LAN access points. However, in this example, the transmission of a beacon in the survey interval T _B is successful in the respective transmission timings.

  Of the above first to third channel examples, the second channel will be further examined. In the second channel, although there are no other wireless LAN access points around the wireless LAN access point 100, beacon transmission has failed. This indicates the possibility that radiation noise that is an interference wave is received from other than the wireless LAN device. For example, there is a possibility that a microwave oven exists near the wireless LAN access point 100, and this transmits a signal corresponding to the second channel.

  On the other hand, in the case of the third channel, although another wireless LAN access point exists near the wireless LAN access point 100, transmission of a beacon from the wireless LAN access point 100 is performed without any problem. Therefore, the third channel is a more appropriate channel than the second channel.

  Of course, in the case of the first channel, there is no other wireless LAN access point near the wireless LAN access point 100, and beacon transmission from the wireless LAN access point 100 is performed without any problem. Therefore, the first channel is a more appropriate channel than the third channel.

  From the above results, when channel selection is limited to the first to third channels, the first channel is the best, the third channel is the next best, and the second channel is the best. It will be bad. Therefore, when limited to the first to third channels, the selected channel storage unit 107 stores the first channel as the best channel.

  FIG. 13 shows an example of an arrangement relationship between a wireless LAN access point that performs channel selection discrimination and a radiation noise generation source such as another wireless LAN access point and another wireless LAN access point. In this figure, a first circle 131 indicates a reception area of the wireless LAN access point 100 that transmits a beacon to investigate the situation. A second circle 132 indicates the radio wave reachable range of the other wireless LAN access point 141. A third circle 133 indicates a radio wave reachable range of the microwave oven 142 as an example of a radiation noise generation source.

The arrangement state shown in FIG. 13 represents an example when the wireless LAN access point 100 selects the second channel in FIG. That is, no other wireless LAN access point 141 exists in the reception area 131 of the wireless LAN access point 100. Therefore, detection of the access point detection section T _A of the other wireless LAN access points is not performed. Further, since the microwave oven 142 near the survey interval T the wireless LAN access point 100, _B is present, the received power level by the carrier sense is equal to or higher than the predetermined threshold value, any transmission of a beacon fails Yes.

  FIG. 14 shows another arrangement relationship of a wireless LAN access point, another wireless LAN access point, and a microwave oven. In the arrangement example shown in FIG. 14, the microwave oven 142 is located slightly away from the wireless LAN access point 100 that performs the situation investigation, and the radiation noise is somewhat reduced.

  On the other hand, in FIG. 14, another wireless LAN access point 141 also exists in the reception area 131 of the wireless LAN access point 100.

FIG. 15 shows an example of beacon detection and beacon transmission results on the X-th channel in the arrangement state shown in FIG. This will be described with reference to FIGS. 11, 12, and 14. However, the different lengths of the survey interval T _B following the detection segment T _A in FIG. 15 and FIG. 12.

In the X-th channel, the detection of the access point is performed at time t _A1 and time t _A2 in the detection section T _A of the other wireless LAN access point, as in the third channel of FIG. Therefore, if the count value of the reception beacon counter 108 shown in FIG. 7 is C _A , the count value C _A is “2” in this example.

In other wireless LAN access point detection section T _A subsequent survey interval T _B, are detected radio waves of the microwave oven 142 in the first carrier sense timing at time t _B1, transmission of a beacon by the wireless LAN access point 100 It has failed. Therefore, the wireless LAN access point 100 attempts to transmit a beacon at the time t _B2 of the second carrier sense when the time T ₂ has elapsed from the time t _B1. Fail.

Therefore, the wireless LAN access point 100 determines that beacon transmission is not possible continuously (step S247), and changes the interval at which carrier sense is performed from time T ₂ to time T ₄ having a shorter cycle than this. To do. This is because the temporal characteristics of radiation noise that becomes an interference wave are grasped in more detail, and the possibility of radio wave transmission by the wireless LAN access point 100 is further explored.

As a result, in the example shown in FIG. 15, the radio wave of the microwave oven 142 is not detected at time t _B3 , and the beacon transmission is successful. Assuming that the count value of the transmission beacon counter 110 is C _B , the count value C _B indicating the number of times beacons have been transmitted so far is “4” in this example.

Since the transmission of the beacon was successful at time t _B3 , the interval until carrier sense is returned from time T ₄ to time T ₂ having a long cycle again (step S 245). However, since beacon transmission fails in the first carrier sense after the elapse of time T ₄ (step S243: N), the count value C _B of the transmission beacon counter 110 is set to “1” again (step S247: N Step S250). And this after the transmission of the beacon fails continuously until the survey period T _B by the transmission of the beacon to the end. It is assumed that the count value C _B2 of the transmission beacon counter 110 at this time is larger than the count value C _B1 of the transmission beacon counter 110 when starting from time t _B1 .

In this case, the wireless LAN access point 100 stores the count values C _B1 and C _B2 in the specific area of the memory 103 as the value of the X-th channel, and at each necessary time as described below. By performing these comparison operations for each channel, it is possible to perform channel mutual selection processing in a relatively poor environment.

  FIG. 16 shows a process of selecting a channel with the best evaluation result in the wireless LAN channel control unit, and embodies the process of step S208 of FIG. This is control for selecting the channel having the best evaluation. This will be described with reference to FIGS.

  First, the wireless LAN channel control unit 106 sets a starting channel initial value for channel selection in the parameter n (step S261). The start channel initial value is, for example, a numerical value “1” representing the first channel. Next, the value “n” is set to the parameter α, and “n + 1” obtained by adding “1” to the value “n” is set to the other parameter β (step S262).

  In this state, the wireless LAN channel control unit 106 evaluates the two channels, the α-th channel and the β-th channel (step S263), and sets the better one of these as the α-th channel (step S264). In the above example, since the value “n” is “1”, the first channel and the second channel are compared, and the channel that is evaluated as good is the α-th channel. In the example shown in FIG. 12, the first channel is selected as a better channel.

  FIG. 17 specifically shows an example of a comparison process of evaluation between two channels, and is a specific example of step S263. This will be described with reference to FIGS.

Wireless LAN channel controller 106 first of all of the α channel the count value C _B of the transmission beacon counter 110 of the β channel is checked whether the "0" (step S281). This is a check of whether all beacon transmissions are successful on both the α-th channel and the β-th channel. If the transmission of the beacon all went well in both channels to determine whether a (Y), the count value C _A of the received beacon counter 108 are both in these first α channel and the β channel "0" (step S282 ).

If the count value C _A is both "0" at the α channel and the β channel (step S282: Y), the communication environment of both channels will be satisfactory. Therefore, the wireless LAN channel control unit 106 may select either the α-th channel or the β-th channel. In this embodiment, in this case, the α-th channel is selected (step S283), and the control for selecting the most appropriate channel is ended (END). Of course, the wireless LAN channel control unit 106 may select either the α-th channel or the β-th channel by further referring to the past history. Further, the priority order when the communication environment is the same may be determined in advance, and either the α-th channel or the β-th channel may be selected in accordance with this.

If at least one of the count values C _A is not “0” in the α-th channel and the β-th channel in step S282 (N), the wireless LAN channel control unit 106 determines the count value C _A of the β-th channel. There is determined greater than the count value C _a of the α channel (step S284). If the larger value of the count value C _A of the β channel (Y), toward the second α channel is that there is less affected by other wireless LAN access points. In this case, the process proceeds to step S283, and the wireless LAN channel control unit 106 selects the α-th channel.

In step S283, if the count value C _A is equal or larger in the α-th channel and the β-th channel (step S284: N), the β-th channel is selected (step S285), and the optimum End the control to select the channel (end).

Then, all at step S281 of the α channel the count value C _B of the transmission beacon counter 110 of the β channel will be described not "0". Count value C _B of the transmission beacon counter 110, and when taking a value of "0" only for one channel as the second channel of FIG. 12, several kinds of count values as the X channel of FIG. 15 There is a case to take. Where applicable count value in channel C _B takes a plurality of types of the count value, it is safer to base the determination of them the maximum value from the viewpoint of determination of the noise situation.

Therefore, when all the count values C _B of the transmission beacon counters 110 of the α-th channel and the β-th channel are not “0” in step S281 (N), the maximum values of the count values C _B are compared with each other. It is determined whether the channel is a β channel (step S286). As a result, in towards the maximum value of the count value C _B of the β channel is greater than that of the α channel (Y), the wireless LAN channel controller 106 proceeds to step S283 of selecting a first α channel Become.

If it is determined to be other than it in step S286 (N), a wireless LAN channel controller 106 determines whether the direction of the count value C _A of the β channel greater than that of the α channel (step S287 ). As a result, if the count value C _A of the β-th channel is larger than that of the α-th channel with respect to the count value C _A (Y), the process proceeds to step S283, and the wireless LAN channel control unit 106 sets the α-th channel. Will choose. In other cases (step S287: N), the process proceeds to step S285, and the wireless LAN channel control unit 106 selects the β-th channel.

  Returning to the description of FIG. Among the two channels evaluated and compared in step S263, the number of the channel evaluated as good is set as the parameter α (step S264). Thereafter, it is checked whether all channels have been evaluated (step S265). Since the first channel and the second channel have only been evaluated (N), the parameter β is incremented by “1” (step S266). Then, the process returns to step S263.

  Thereafter, when the evaluation up to the thirteenth channel is completed in the same manner (step S265: Y), the α-th channel at that time is the most appropriate channel. Therefore, this α-th channel is selected as a channel used by the wireless LAN access point 100 (step S267), and the channel selection process is ended (END).

  According to the present embodiment described above, the channel used by the wireless LAN access point 100 can be a channel other than the channel having the same frequency as that of other surrounding wireless LAN access points. Further, when there is radiation noise that becomes an interference wave in the surroundings, selection of a channel having a frequency affected by this can be avoided. Further, even when the communication environment is bad, it is possible to automatically select a channel in which the wireless LAN access point 100 is not affected as much as possible.

  <Deformability of invention>

  FIG. 18 shows the configuration of a wireless LAN access point in a modification of the present invention. In the modified example of the wireless LAN access point 100A, the same parts as those in FIG.

  In the wireless LAN access point 100A of this modification, a trigger trigger unit 301 and a display unit 302 are connected to a bus 102 such as a data bus. The memory 103A stores a slightly modified version of the control program of the embodiment as a control program executed by the CPU 101, and a setting table for each channel.

  Specifically, the trigger trigger unit 301 generates a push button switch attached to a housing (not shown) of the wireless LAN access point 100A and the start trigger described in step S201 in FIG. 8 when the push button switch is pressed. Input circuit. The display unit 302 includes a liquid crystal display or an organic EL display (organic electroluminescence display). When the operator of the wireless LAN access point 100A presses the push button switch described above, the channel selection operation on the display unit 302 has started, the channel is being selected, and the best channel has been selected. Are displayed sequentially.

  FIG. 19 corresponds to FIG. 9 and shows the channels that can be set by the wireless LAN access point of the modification and the center frequencies thereof. In the modified wireless LAN access point 100A, a total of 11 center frequencies can be selected. The example shown in FIG. 19 is based on the IEEE (Institute of Electrical and Electronic Engineers) 802.11a standard. On the other hand, the example shown in the embodiment shown in FIG. 9 is based on the IEEE802.11b standard.

  According to the wireless LAN access point 100A of the modified example described above, an optimal empty channel or frequency can be selected at a predetermined time such as initial setting as in the previous embodiment.

  In addition, when the location of the wireless LAN access point 100A is moved or the surrounding communication environment is changed, the optimum channel can be easily selected by operating the trigger trigger unit 301. In addition, the operator's knowledge and experience are not required for frequency selection at this time. Furthermore, when the wireless LAN access point 100A is performing a channel selection operation, this is displayed on the display unit 302, so that the operator can feel secure.

  In the embodiment and its modifications, the channel selection coefficient as a weight between channels for selecting a channel (center frequency) is set to “1”, but evaluation is performed by appropriately setting the channel selection coefficient for each channel. You may do it. As an example, a channel selection coefficient may be obtained from channel usage and the number of consecutive failures during beacon transmission, and these settings may be made.

  Further, when the distance between the wireless LAN access point 100, 100A and another wireless LAN access point or a radiation noise generation source is known, the weight of the channel selection coefficient may be adjusted according to the distance. . When there is an equivalent channel (center frequency) at the time of selection, it is also possible to select according to a predetermined priority order.

  Further, in the embodiments and the modifications thereof, the invention has been described on the premise of the IEEE802.11 standard, but it goes without saying that the present invention is not particularly limited with respect to the frequency and communication method to be used.

Furthermore, in the embodiment, the beacon transmission cycle is shortened from the time T ₂ to the time T ₄ when the beacon transmission fails continuously, but the beacon transmission succeeds when it fails once. Naturally, the period of transmitting the beacons may be shortened from the time T ₂ to the period of the time T ₄ .

  Some or all of the embodiments described above are described as in the following supplementary notes, but are not limited to the following descriptions.

(Appendix 1)
Frequency selection means for sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
Beacon transmitting means for repeatedly transmitting a beacon as a radio beacon using the center frequency selected by the frequency selecting means at a predetermined search period within a predetermined period of time as a time per channel,
When this beacon transmission means starts transmitting a beacon, the reception power level of the carrier frequency is sensed prior to this, and when this reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure. Carrier sense means for transmitting a beacon only when it is less than the threshold value,
When the beacon transmission of the beacon transmission unit fails by the carrier sense unit, transmission by the beacon transmission unit is performed at a failure time cycle as a predetermined cycle within the situation investigation time until the beacon transmission is successful. Beacon transmission control means for repeatedly trying;
A transmission failure counting means for counting the number of times the beacon transmission has failed continuously when transmission is attempted by the beacon transmission control means for each beacon using the channel of the center frequency selected by the frequency selection means;
The count value of the transmission failure counting means is compared with the plurality of channels selected by the frequency selecting means, and the channel of the center frequency with the lowest number of beacon transmission failures by the beacon transmitting means is selected as the communication channel. And a channel selection means.

(Appendix 2)
The communication apparatus according to claim 1, further comprising weighting means for assigning a predetermined weight for each center frequency to the count value of the transmission failure counting means.

(Appendix 3)
The communication apparatus according to appendix 1, wherein the failure period is set shorter than the investigation period.

(Appendix 4)
The frequency selecting means selects one center frequency in a predetermined priority order when there are a plurality of minimum center frequencies with which the beacon transmission fails by the beacon transmitting means. Communication equipment.

(Appendix 5)
The communication apparatus according to claim 1, further comprising a switch for manually starting selection of a center frequency by the frequency selection means.

(Appendix 6)
The communication apparatus according to claim 1, further comprising display means for displaying a history from the start of selection of the center frequency by the frequency selection means to selection of a frequency for communication by the frequency selection means.

(Appendix 7)
Frequency selection means for sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
Beacon transmitting means for repeatedly transmitting a beacon as a radio beacon using the center frequency selected by the frequency selecting means at a predetermined search period within a predetermined period of time as a time per channel,
When this beacon transmission means starts transmitting a beacon, the reception power level of the carrier frequency is sensed prior to this, and when this reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure. Carrier sense means for transmitting a beacon only when it is less than the threshold value,
When the beacon transmission of the beacon transmission unit fails by the carrier sense unit, transmission by the beacon transmission unit is performed at a failure time cycle as a predetermined cycle within the situation investigation time until the beacon transmission is successful. Beacon transmission control means for repeatedly trying;
A transmission failure counting means for counting the number of times the beacon transmission has failed continuously when transmission is attempted by the beacon transmission control means for each beacon using the channel of the center frequency selected by the frequency selection means;
Beacon receiving means for receiving beacons transmitted by surrounding access points at a predetermined access point detection time prior to the start of each of the situation investigation times;
Received beacon counting means for counting the number of beacons received by the beacon receiving means within the access point detection time for each beacon using the channel of the center frequency selected by the frequency selecting means;
The count value of the reception beacon counting unit and the count value of the transmission failure counting unit are compared in the plurality of channels selected by the frequency selection unit, and the number of times the beacon transmission by the beacon transmission unit fails is minimum. A wireless LAN access point, comprising: a channel selection unit that selects a channel having a lowest center frequency as a communication channel.

(Appendix 8)
The wireless LAN access point according to appendix 7, further comprising weighting means for assigning a predetermined weight for each center frequency to the count value of the transmission failure counting means.

(Appendix 9)
The wireless LAN access point according to appendix 7, wherein the failure period is set shorter than the investigation period.

(Appendix 10)
The frequency selecting means selects one center frequency in a predetermined priority order when there are a plurality of minimum center frequencies with which the beacon transmission fails by the beacon transmitting means. Wireless LAN access point.

(Appendix 11)
The wireless LAN access point according to appendix 7, further comprising a switch for manually starting selection of a center frequency by the frequency selection means.

(Appendix 12)
The wireless LAN access point according to appendix 7, further comprising display means for displaying a history from the start of selection of a center frequency by the frequency selection means to selection of a communication frequency by the frequency selection means.

(Appendix 13)
The wireless LAN access point according to appendix 8, wherein the weighting unit performs weighting according to a distance between the surrounding access point and the own device.

(Appendix 14)
A frequency selection step of sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
A beacon transmission step of repeatedly transmitting a beacon as a radio beacon using the center frequency selected in this frequency selection step as a time per channel in a predetermined period of time within a predetermined period of time for investigation.
When the beacon transmission is started in this beacon transmission step, the reception power level of the carrier frequency is sensed prior to this, and when the reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure and the predetermined power is not transmitted. A carrier sense step for transmitting a beacon only when the threshold is less than
When the beacon transmission in the beacon transmission step is unsuccessful in this carrier sense step, the transmission by the beacon transmission step is performed at a failure time period as a predetermined period within the situation investigation time until the beacon transmission is successful. A beacon transmission control step for repeatedly trying,
A transmission failure counting step of counting the number of times the beacon transmission has failed continuously when transmission is attempted by this beacon transmission control step for each beacon using the channel of the center frequency selected in the frequency selection step;
The count value obtained in this transmission failure count step is compared with the plurality of channels selected in the frequency selection step, and the channel having the lowest frequency of beacon transmission failure in the beacon transmission step is selected as a communication channel. And a channel selection step.

(Appendix 15)
A frequency selection step of sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
A beacon transmission step of repeatedly transmitting a beacon as a radio beacon using the center frequency selected in this frequency selection step as a time per channel in a predetermined period of time within a predetermined period of time for investigation.
When the beacon transmission is started in this beacon transmission step, the reception power level of the carrier frequency is sensed prior to this, and when the reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure and the predetermined power is not transmitted. A carrier sense step for transmitting a beacon only when the threshold is less than
When the beacon transmission in the beacon transmission step is unsuccessful in this carrier sense step, the transmission by the beacon transmission step is performed at a failure time period as a predetermined period within the situation investigation time until the beacon transmission is successful. A beacon transmission control step for repeatedly trying,
A transmission failure counting step of counting the number of times the beacon transmission has failed continuously when transmission is attempted by this beacon transmission control step for each beacon using the channel of the center frequency selected in the frequency selection step;
A beacon receiving step of receiving beacons transmitted by surrounding access points at a predetermined access point detection time prior to the start of each of the situation investigation times;
A reception beacon counting step of counting the number of beacons received within the access point detection time in this beacon reception step for each beacon using the channel of the center frequency selected in the frequency selection step;
The count value in the reception beacon count step and the count value in the transmission failure count step are compared in the plurality of channels selected in the frequency selection step, and the number of times the beacon transmission fails in the beacon transmission step is the lowest. A channel selection method comprising: a channel selection step of selecting a channel having the lowest center frequency as the communication channel in the reception beacon counting step.

(Appendix 16)
In the computer of the communication device,
A frequency selection process for sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
A beacon transmission process for repeatedly transmitting a beacon as a radio beacon using the center frequency selected in this frequency selection process at a predetermined search period within a predetermined period of time as a period per channel
When the beacon transmission is started in this beacon transmission process, the reception power level of the carrier frequency is sensed prior to this, and when the reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure. Carrier sense processing that transmits a beacon only when the threshold is less than
When the beacon transmission of the beacon transmission process fails by this carrier sense process, the transmission by the beacon transmission process is performed at a failure period as a predetermined period within the situation investigation time until the beacon transmission is successful. Beacon transmission control processing to try repeatedly;
A transmission failure counting process that counts the number of times a beacon transmission has failed continuously when transmission is attempted by this beacon transmission control process for each beacon using the channel of the center frequency selected in the frequency selection process;
The count value obtained by the transmission failure count process is compared with the plurality of channels selected in the frequency selection process, and the channel with the center frequency with the lowest number of beacon transmission failures in the beacon transmission process is selected as a communication channel. And a channel selection program for executing the channel selection process.

(Appendix 17)
To the computer of the wireless LAN access point,
A frequency selection process for sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
A beacon transmission process for repeatedly transmitting a beacon as a radio beacon using the center frequency selected in this frequency selection process at a predetermined search period within a predetermined period of time as a period per channel
When the beacon transmission is started in this beacon transmission process, the reception power level of the carrier frequency is sensed prior to this, and when the reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure. Carrier sense processing that transmits a beacon only when the threshold is less than
When the beacon transmission of the beacon transmission process fails by this carrier sense process, the transmission by the beacon transmission process is performed at a failure period as a predetermined period within the situation investigation time until the beacon transmission is successful. Beacon transmission control processing to try repeatedly;
A transmission failure counting process that counts the number of times a beacon transmission has failed continuously when transmission is attempted by this beacon transmission control process for each beacon using the channel of the center frequency selected in the frequency selection process;
Beacon reception processing for receiving beacons transmitted by surrounding access points at a predetermined access point detection time prior to the start of each of the situation investigation times;
A reception beacon counting process for counting the number of beacons received within the access point detection time in the beacon reception process for each beacon using the channel of the center frequency selected in the frequency selection process;
The count value in the reception beacon count process and the count value in the transmission failure count process are compared in the plurality of channels selected in the frequency selection process, and the number of times that the beacon transmission by the beacon transmission process fails is the lowest. A channel selection program for executing a channel selection process for selecting a channel having the lowest center frequency as a communication channel in the reception beacon count process.

DESCRIPTION OF SYMBOLS 10 Communication apparatus 11, 21 Frequency selection means 12, 22 Beacon transmission means 13, 23 Carrier sense means 14, 24 Beacon transmission control means 15, 25 Transmission failure count means 16, 28 Channel selection means 20, 100, 100A Wireless LAN access point 26 Beacon reception means 27 Reception beacon counting means 30, 40 Channel selection method 31, 41 Frequency selection step 32, 42 Beacon transmission step 33, 43 Carrier sense step 34, 44 Beacon transmission control step 35, 45 Transmission failure count step 36, 48 Channel selection step 46 Beacon reception step 47 Reception beacon count step 50, 60 Channel selection program 51, 61 Frequency selection processing 52, 62 Beacon transmission processing 53, 63 Key Riasensu processing 54,64 beacon transmission control processing 55 and 65 transmit failure count process 56, 68 channel selection process 66 beacon reception process 67 receives the beacon count process 101 CPU
103, 103A Memory 104 Wireless LAN transmission unit 105 Wireless LAN reception unit 106 Wireless LAN channel control unit 107 Selected channel storage unit 108 Reception beacon counter 109 Beacon reception control unit 110 Transmission beacon counter 131 Reception area of wireless LAN access point 132 Other wireless LAN Radio wave reachable range of access point 133 Radio wave reachable range of microwave oven 141 Other wireless LAN access point 142 Microwave oven 301 Trigger trigger unit 302 Display unit T _A Other wireless LAN access point detection zone T _B Beacon transmission status survey zone C _A Count value (for reception beacon counter) C _B Count value (for transmission beacon counter)

Claims (10)

Frequency selection means for sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
Beacon transmitting means for repeatedly transmitting a beacon as a radio beacon using the center frequency selected by the frequency selecting means at a predetermined search period within a predetermined period of time as a time per channel,
When this beacon transmission means starts transmitting a beacon, the reception power level of the carrier frequency is sensed prior to this, and when this reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure. Carrier sense means for transmitting a beacon only when it is less than the threshold value,
When the beacon transmission of the beacon transmission unit fails by the carrier sense unit, transmission by the beacon transmission unit is performed at a failure time cycle as a predetermined cycle within the situation investigation time until the beacon transmission is successful. Beacon transmission control means for repeatedly trying;
A transmission failure counting means for counting the number of times the beacon transmission has failed continuously when transmission is attempted by the beacon transmission control means for each beacon using the channel of the center frequency selected by the frequency selection means;
The count value of the transmission failure counting means is compared with the plurality of channels selected by the frequency selecting means, and the channel of the center frequency with the lowest number of beacon transmission failures by the beacon transmitting means is selected as the communication channel. And a channel selection means.   2. The communication apparatus according to claim 1, further comprising weighting means for assigning a predetermined weight for each center frequency to the count value of the transmission failure counting means.   The communication apparatus according to claim 1, wherein the failure period is set shorter than the investigation period.   The frequency selecting means selects one center frequency in a predetermined priority order when there are a plurality of minimum center frequencies with which the beacon transmission fails by the beacon transmitting means. The communication device described.   A switch for manually starting the selection of the center frequency by the frequency selection means, and a display means for displaying the history from the start of the selection of the center frequency by the frequency selection means to the selection of the frequency for communication by the frequency selection means. The communication apparatus according to claim 1, wherein: Frequency selection means for sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
Beacon transmitting means for repeatedly transmitting a beacon as a radio beacon using the center frequency selected by the frequency selecting means at a predetermined search period within a predetermined period of time as a time per channel,
When this beacon transmission means starts transmitting a beacon, the reception power level of the carrier frequency is sensed prior to this, and when this reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure. Carrier sense means for transmitting a beacon only when it is less than the threshold value,
When the beacon transmission of the beacon transmission unit fails by the carrier sense unit, transmission by the beacon transmission unit is performed at a failure time cycle as a predetermined cycle within the situation investigation time until the beacon transmission is successful. Beacon transmission control means for repeatedly trying;
A transmission failure counting means for counting the number of times the beacon transmission has failed continuously when transmission is attempted by the beacon transmission control means for each beacon using the channel of the center frequency selected by the frequency selection means;
Beacon receiving means for receiving beacons transmitted by surrounding access points at a predetermined access point detection time prior to the start of each of the situation investigation times;
Received beacon counting means for counting the number of beacons received by the beacon receiving means within the access point detection time for each beacon using the channel of the center frequency selected by the frequency selecting means;
The count value of the reception beacon counting unit and the count value of the transmission failure counting unit are compared in the plurality of channels selected by the frequency selection unit, and the number of times the beacon transmission by the beacon transmission unit fails is minimum. A wireless LAN access point, comprising: a channel selection unit that selects a channel having a lowest center frequency as a communication channel. A frequency selection step of sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
A beacon transmission step of repeatedly transmitting a beacon as a radio beacon using the center frequency selected in this frequency selection step as a time per channel in a predetermined period of time within a predetermined period of time for investigation.
When the beacon transmission is started in this beacon transmission step, the reception power level of the carrier frequency is sensed prior to this, and when the reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure and the predetermined power is not transmitted. A carrier sense step for transmitting a beacon only when the threshold is less than
When the beacon transmission in the beacon transmission step is unsuccessful in this carrier sense step, the transmission by the beacon transmission step is performed at a failure time period as a predetermined period within the situation investigation time until the beacon transmission is successful. A beacon transmission control step for repeatedly trying,
A transmission failure counting step of counting the number of times the beacon transmission has failed continuously when transmission is attempted by this beacon transmission control step for each beacon using the channel of the center frequency selected in the frequency selection step;
The count value obtained in this transmission failure count step is compared with the plurality of channels selected in the frequency selection step, and the channel having the lowest frequency of beacon transmission failure in the beacon transmission step is selected as a communication channel. And a channel selection step. A frequency selection step of sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
A beacon transmission step of repeatedly transmitting a beacon as a radio beacon using the center frequency selected in this frequency selection step as a time per channel in a predetermined period of time within a predetermined period of time for investigation.
When the beacon transmission is started in this beacon transmission step, the reception power level of the carrier frequency is sensed prior to this, and when the reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure and the predetermined power is not transmitted. A carrier sense step for transmitting a beacon only when the threshold is less than
When the beacon transmission in the beacon transmission step is unsuccessful in this carrier sense step, the transmission by the beacon transmission step is performed at a failure time period as a predetermined period within the situation investigation time until the beacon transmission is successful. A beacon transmission control step for repeatedly trying,
A transmission failure counting step of counting the number of times the beacon transmission has failed continuously when transmission is attempted by this beacon transmission control step for each beacon using the channel of the center frequency selected in the frequency selection step;
A beacon receiving step of receiving beacons transmitted by surrounding access points at a predetermined access point detection time prior to the start of each of the situation investigation times;
A reception beacon counting step of counting the number of beacons received within the access point detection time in this beacon reception step for each beacon using the channel of the center frequency selected in the frequency selection step;
The count value in the reception beacon count step and the count value in the transmission failure count step are compared in the plurality of channels selected in the frequency selection step, and the number of times the beacon transmission fails in the beacon transmission step is the lowest. A channel selection method comprising: a channel selection step of selecting a channel having the lowest center frequency as the communication channel in the reception beacon counting step. In the computer of the communication device,
A frequency selection process for sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
A beacon transmission process for repeatedly transmitting a beacon as a radio beacon using the center frequency selected in this frequency selection process at a predetermined search period within a predetermined period of time as a period per channel
When the beacon transmission is started in this beacon transmission process, the reception power level of the carrier frequency is sensed prior to this, and when the reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure. Carrier sense processing that transmits a beacon only when the threshold is less than
When the beacon transmission of the beacon transmission process fails by this carrier sense process, the transmission by the beacon transmission process is performed at a failure period as a predetermined period within the situation investigation time until the beacon transmission is successful. Beacon transmission control processing to try repeatedly;
A transmission failure counting process that counts the number of times a beacon transmission has failed continuously when transmission is attempted by this beacon transmission control process for each beacon using the channel of the center frequency selected in the frequency selection process;
The count value obtained by the transmission failure count process is compared with the plurality of channels selected in the frequency selection process, and the channel with the center frequency with the lowest number of beacon transmission failures in the beacon transmission process is selected as a communication channel. And a channel selection program for executing the channel selection process. To the computer of the wireless LAN access point,
A frequency selection process for sequentially selecting the center frequencies of a plurality of predetermined channels one by one;
A beacon transmission process for repeatedly transmitting a beacon as a radio beacon using the center frequency selected in this frequency selection process at a predetermined search period within a predetermined period of time as a period per channel
When the beacon transmission is started in this beacon transmission process, the reception power level of the carrier frequency is sensed prior to this, and when the reception power level is equal to or higher than a predetermined threshold, the beacon is not transmitted as a failure. Carrier sense processing that transmits a beacon only when the threshold is less than
When the beacon transmission of the beacon transmission process fails by this carrier sense process, the transmission by the beacon transmission process is performed at a failure period as a predetermined period within the situation investigation time until the beacon transmission is successful. Beacon transmission control processing to try repeatedly;
A transmission failure counting process that counts the number of times a beacon transmission has failed continuously when transmission is attempted by this beacon transmission control process for each beacon using the channel of the center frequency selected in the frequency selection process;
Beacon reception processing for receiving beacons transmitted by surrounding access points at a predetermined access point detection time prior to the start of each of the situation investigation times;
A reception beacon counting process for counting the number of beacons received within the access point detection time in the beacon reception process for each beacon using the channel of the center frequency selected in the frequency selection process;
The count value in the reception beacon count process and the count value in the transmission failure count process are compared in the plurality of channels selected in the frequency selection process, and the number of times that the beacon transmission by the beacon transmission process fails is the lowest. A channel selection program for executing a channel selection process for selecting a channel having the lowest center frequency as a communication channel in the reception beacon count process.

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