JP2014135554A - Radio terminal, program and method capable of setting use frequency band considering reception signal strength - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a radio terminal that is able to avoid a situation in which radio waves for wireless LAN communication interfere in real time.SOLUTION: A radio terminal according to the invention comprises: a wireless LAN interface capable of receiving, from a plurality of wireless access points (AP), signals including connection destination identifier information and information on frequency bands used by the wireless AP; AP information management means for, per connection destination identifier included in the received signals, associating and managing the frequency band with the reception signal strength of the signal; frequency band determination means for determining a frequency band isolated by equal to or more than a prescribed frequency interval from all the frequency bands associated with reception signal strength equal to or more than a prescribed strength threshold, or from all the other frequency bands within the frequency bands associated with reception signal strength equal to or more than the prescribed strength threshold; and communication control means for setting the determined frequency band as a use frequency band used for communication connection.

Description

  The present invention relates to a communication connection technology in a wireless local area network (LAN).

  With the widespread use of smartphones, mobile phones, etc., the amount of data communication over mobile phone communication networks has increased rapidly and is expected to increase further in the future. For this reason, efforts are being actively made to offload the data communication currently being performed via the mobile phone communication network to other networks such as a wireless LAN. Here, the wireless LAN can be constructed at a lower cost than the installation of the mobile phone base station, and is easily spread.

  For example, a smartphone user uses a wireless LAN function such as Wi-Fi (trademark registration) installed in a smartphone when connected to the Internet via a wireless access point (AP) installed in the house. To do. Thereby, since data communication can be performed without going through a mobile phone base station, the communication load of the mobile phone communication network can be reduced.

  As a technology related to this offloading, for example, in Patent Document 1, a mobile phone line is used in view of demand for high communication quality for voice calls, and a wireless LAN line is used when a large amount of data is transmitted and received. The technique used is disclosed. In this technique, the selection criteria for these lines are fixed.

  On the other hand, in Patent Document 2, the current position is detected by a GPS (Global Positioning System) function, information on the wireless LAN at the current position is acquired to determine whether communication is possible, and communication is possible. In this case, a technique for performing communication by switching to a wireless LAN is disclosed.

  Further, Patent Document 3 discloses a technique for selecting communication by a wireless LAN only when the radio wave intensity of the wireless LAN and the quality of the fixed line that is the backbone of the AP are above a certain level. Here, the portable wireless terminal investigates the communication quality such as transmission delay or transmission error rate in the access route to the communication destination, and based on this result, the communication quality is set to a level required for a call or data transfer. It is determined whether it is satisfied. If the communication quality satisfies this level as a result of the determination, communication with the communication destination terminal is performed via the wireless LAN via the Internet.

Japanese Patent Laying-Open No. 2003-110751 JP 2005-188060 A JP 2008-219733 A

  However, even if the conventional technology as described above is used, the problem that the communication speed is lowered or communication becomes impossible due to the interference of radio waves for wireless LAN communication is solved in real time. It is difficult to do.

  Actually, a wireless LAN device such as Wi-Fi (registered trademark) may normally emit radio waves at any location as long as it conforms to simple regulations such as power and mask. As a result, the problem of interference of communication radio waves is likely to occur due to the presence of a wireless AP or a surrounding wireless LAN device using the same frequency band. In order to avoid such a wireless LAN communication failure, the user must fully grasp the current communication status, and in some cases, it is necessary to perform an operation such as manually turning off the wireless LAN. For this reason, there are a large number of users who think that “3G (mobile phone communication network) can be kept even if it is a little late because it is troublesome”, and as a result, further improvement in the offload rate to the wireless LAN has not progressed.

  Here, for example, even if the technique of Patent Document 1 is used, the selection criteria for using a mobile phone line or a wireless LAN line is fixed, and the communication connection status in a wireless LAN that changes with time Depending on the situation, there may arise a problem that stable data communication cannot be secured.

  In addition, the technology of Patent Document 2 certainly acquires information about whether or not communication is possible with respect to the wireless AP based on the current position by the GPS function, and determines whether or not to connect to the wireless LAN. However, it is still difficult to hold communication information of a wireless LAN such as home or public Wi-Fi (registered trademark) in real time. As a result, as in the technique of Patent Document 1, there may be a problem that stable communication cannot be ensured.

  Furthermore, in the technique of Patent Document 3, the portable wireless terminal certainly monitors the status of radio waves transmitted from the wireless AP at all times, and determines whether communication with the wireless AP is possible. Here, when it is determined that communication with the wireless AP is possible, the control unit of the portable wireless terminal switches the communication unit to the communication unit for wireless LAN. As described above, in order to transmit and receive information that emphasizes real-time characteristics such as voice information and image information, the mobile wireless terminal must frequently switch the communication means to be used between the wireless LAN and the mobile phone communication network. . As a result, the communication quality deteriorates at the time of switching, and the battery power consumption increases.

  Therefore, an object of the present invention is to provide a wireless terminal, a wireless communication activation program, and a wireless communication activation method that can avoid a situation in which radio waves for wireless LAN communication interfere in real time.

According to the present invention, a wireless terminal connectable to each of a plurality of wireless access points (APs) via a wireless LAN,
A wireless LAN interface capable of receiving a signal including connection destination identifier information and frequency band information used by the wireless AP from the wireless AP;
AP information management means for managing the frequency band and the received signal strength of the signal in association with each other for each connection destination identifier included in the received signal;
From all of the frequency bands associated with the received signal strength equal to or higher than the predetermined strength threshold or from all other frequency bands within the frequency band associated with the received signal strength equal to or higher than the predetermined strength threshold A frequency band determining means for determining a frequency band separated by a frequency interval or more;
There is provided a wireless terminal having communication control means for setting a determined frequency band to a use frequency band used for communication connection.

  As an embodiment of this wireless terminal, the frequency band determining means sets a strength value higher than a predetermined strength threshold as a new strength threshold when a frequency band separated by a predetermined frequency interval or more cannot be determined. Based on the frequency band associated with the received signal strength equal to or greater than the new strength threshold, frequency bands separated by a predetermined frequency interval or more are investigated, and the intensity is determined until a frequency band separated by the predetermined frequency interval or more is determined. It is also preferable to set the threshold value to a higher value sequentially.

  Further, the frequency band determining means sets a frequency interval shorter than the predetermined frequency interval as a new frequency interval when a frequency band separated by a predetermined frequency interval or more cannot be determined, and exceeds the new frequency interval. It is also preferable to use the frequency intervals that are set to smaller values sequentially with a predetermined interval lower limit as a limit until a frequency band that is separated by more than the set frequency interval is determined by investigating the separated frequency bands.

  As one embodiment of the wireless terminal of the present invention, the wireless LAN interface is connected to a predetermined wireless AP among a plurality of wireless APs, and the communication control means communicates with the predetermined wireless AP connected for communication. It is also preferable to change the frequency band used for connection to the set use frequency band. Here, the predetermined wireless AP is, for example, a home wireless AP, and according to the present embodiment, an optimum frequency band (channel) can be set again with the home wireless AP.

  Furthermore, as another embodiment of the wireless terminal of the present invention, the wireless LAN interface is configured such that when a received signal strength of a signal including a connection destination identifier of a predetermined wireless AP is equal to or higher than a predetermined proximity strength threshold, the predetermined wireless AP It is also preferable to send a communication connection inquiry request to the address.

In this embodiment,
Based on the arrival time or phase difference of the electromagnetic wave or ultrasonic wave output from the predetermined wireless AP in response to the electromagnetic wave or ultrasonic wave output from the wireless terminal, or in the electromagnetic wave or ultrasonic wave output from the predetermined wireless AP A distance measurement / determination unit is further provided for measuring the distance to the predetermined wireless AP based on the strength at the time of reception, and determining whether the distance is equal to or less than a predetermined distance threshold,
The wireless LAN interface also preferably transmits a communication connection inquiry request to a predetermined wireless AP when a true determination is made by the distance measurement / determination unit.

  Furthermore, as one embodiment of the wireless terminal of the present invention, the communication control means accesses a HTTP (HyperText Transfer Protocol) server unit included in a predetermined wireless AP and sets a frequency band used for communication connection with the predetermined wireless AP. It is also preferable to change to the set use frequency band.

  Furthermore, as another embodiment of the wireless terminal according to the present invention, the frequency band determining means includes a predetermined frequency from all other frequency bands within a frequency band associated with a received signal strength equal to or higher than a predetermined strength threshold. The communication control unit determines a frequency band separated by an interval or more and causes the wireless LAN interface to transmit a communication connection inquiry request to a wireless AP having a connection destination identifier associated with the determined frequency band. Is also preferable. According to the present embodiment, it is possible to select a wireless AP using an optimal frequency band (channel) and establish a communication connection.

According to the present invention, there is further provided a frequency band determination program for causing a computer mounted on a wireless terminal connectable to each of a plurality of wireless APs via a wireless LAN,
The wireless terminal includes a wireless LAN interface capable of receiving a signal including connection destination identifier information and frequency band information used by the wireless AP from the wireless AP,
The above program
AP information management means for managing the frequency band and the received signal strength of the signal in association with each other for each connection destination identifier included in the received signal;
From all of the frequency bands associated with the received signal strength equal to or higher than the predetermined strength threshold or from all other frequency bands within the frequency band associated with the received signal strength equal to or higher than the predetermined strength threshold A frequency band determining means for determining a frequency band separated by a frequency interval or more;
There is provided a frequency band determination program for causing a computer to function as communication control means for setting a determined frequency band to a use frequency band used for communication connection.

According to the present invention, there is further provided a frequency band determination method in a wireless terminal connectable to each of a plurality of wireless APs via a wireless LAN,
A first step of receiving a signal including connection destination identifier information and information on a frequency band used by the wireless AP from the wireless AP;
A second step of managing the frequency band and the received signal strength of the signal in association with each other for each connection destination identifier included in the received signal;
From all of the frequency bands associated with the received signal strength equal to or higher than the predetermined strength threshold or from all other frequency bands within the frequency band associated with the received signal strength equal to or higher than the predetermined strength threshold A third step of determining frequency bands separated by a frequency interval or more;
There is provided a frequency band determination method including a fourth step of setting the determined frequency band to a use frequency band used for communication connection.

  According to the wireless terminal, the frequency band determination program, and the method of the present invention, it is possible to avoid a situation in which radio waves for wireless LAN communication interfere with each other in real time.

1 is a configuration diagram of a wireless LAN system using a wireless terminal according to the present invention, and a schematic diagram illustrating a setting example of a frequency band (channel) of a wireless LAN. 1 is a functional configuration diagram showing an embodiment of a wireless terminal 1. FIG. It is a sequence diagram which shows one Embodiment of the frequency band determination method by this invention. It is a sequence diagram which shows other embodiment of the frequency band determination method by this invention. It is the schematic which shows one Embodiment of AP information table which concerns on this invention. 4 is a flowchart illustrating an embodiment of channel determination according to the present invention.

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

[Wireless LAN system]
FIG. 1 is a configuration diagram of a wireless LAN (Local Area Network) system using a wireless terminal according to the present invention, and a schematic diagram showing a setting example of a frequency band (channel) of the wireless LAN.

  According to FIG. 1A, a wireless terminal 1 as an embodiment of a wireless terminal according to the present invention is a portable information device such as a smartphone or a tablet computer, and is a plurality of wireless access points (AP). Each of APa20, APb21, APc22 and APd23 can be connected via a wireless LAN. Here, the APa 20 is a home wireless LAN / AP installed in the user's house.

  APa20, APb21, APc22, and APd23 are wireless LAN relay stations that enable communication connection to the Internet 4 via access networks 30, 31, and 32, respectively. The access networks 30, 31 and 32 are, for example, an optical fixed line, an ADSL (Asymmetric Digital Subscriber Line), a wireless LAN such as Wi-Fi (registered trademark), WiMAX (Worldwide Interoperability for Microwave Access), LTE (Long Term Evolution). Or 3G (3rd Generation).

Similarly, as shown in FIG. 1A, the user has the wireless terminal 1 and enters his / her home, and the wireless terminal 1 automatically establishes communication connection with the APa 20 which is a home wireless LAN / AP. . At this time, the frequency band used for this communication is set to one channel. Here, the wireless terminal 1
(A) A signal (for example, a beacon or a probe response) including information on a connection destination identifier and information on a frequency band (channel) used by each of the APa 20 to 23 is received from the surrounding APa 20 to 23. .
Here, although the connection destination identifier is, for example, an ESSID (Extended Service Set Identifier), the ESSID is hereinafter abbreviated as SSID.

Next, the wireless terminal 1
(B) For each connection destination identifier (SSID) included in the received signal (beacon or probe response), the frequency band (channel) is associated with the received signal strength of the signal (for example, RSSI (Received Signal Strength indication)). Manage.

Furthermore, the wireless terminal 1
(C) A predetermined frequency interval (channel interval) or more from all other frequency bands (channels) within a frequency band (channel) associated with a received signal strength (RSSI) greater than or equal to a predetermined intensity threshold Th _i Decide on a separate frequency band (channel),
(D) The determined frequency band (channel) is set to a used frequency band (used channel) used for communication connection. The channel interval is the channel number interval. For example, the channel interval between 1 channel and 6 channels is defined as 5.

As described above, in other words, the wireless terminal 1 performs a channel scan, monitors the received signal strength (RSSI) and frequency band (channel) of the surrounding APas 20 to 23, and receives the received signal strength (RSSI) equal to or higher than the predetermined strength threshold Th _i. ), A frequency band (channel) that is sufficiently separated from the others is selected, and the used channel is optimized.

  As a result, the radio terminal 1 is superimposed on the frequency band (channel) of the signal radio wave used in the surrounding APas 20 to 23 and having a signal strength sufficient to cause interference. Less frequency bands (channels) can be determined in real time. As a result, a situation in which radio waves for wireless LAN communication interfere with each other can be avoided in real time, and a good communication speed is maintained.

In addition, when a frequency band (channel) separated by a predetermined frequency interval (channel interval) or more cannot be determined, it is also preferable to set an intensity value higher than the predetermined intensity threshold Th _i as a new intensity threshold Th _{i + 1} . In this case, frequency bands (channels) separated by a predetermined frequency interval (channel interval) or more are investigated based on the frequency band (channel) associated with the received signal strength (RSSI) greater than or equal to the new strength threshold Th _{i + 1.} The intensity threshold Th _i is successively set to a higher value until a frequency band (channel) separated by a predetermined frequency interval (channel interval) or more is determined.

  FIG. 1B shows a channel frequency band in IEEE802.11b / g, which is a wireless LAN standard. The frequency band mainly used in wireless LAN is the 2.4 GHz band, and many wireless LAN communication devices are compatible with the IEEE 802.11b / g / n system. In wireless LAN communication, a frequency band to be used is divided to form a plurality of channels (frequency bands) so that a plurality of devices can communicate simultaneously.

  The channel shown in FIG. 1B is a total of 14 channels of 1 to 13 channels provided in increments of 5 MHz from 1 channel with a center frequency of 2412 MHz to 13 channels with a center frequency of 2472 MHz and 14 channels with a center frequency of 2484 MHz. It has become.

  Even when multiple channels are set in this way, if there is another wireless AP that uses the same channel and a wireless LAN communication device connected to it within the reach of the radio wave, interference between communication radio waves occurs. As a result, the communication speed decreases and communication may become impossible.

  Here, the communication speed decreases because the wireless LAN detects the radio waves of other wireless LAN communication devices communicating on the same channel and waits for a random time after the channel is free. This is due to the fact that an interference avoidance technique called CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) is started.

  Further, the wireless AP transmits a beacon signal once every 100 milliseconds. The transmission time of this beacon signal is 1 millisecond. Here, it is assumed that a channel cannot be selected and there are 10 wireless APs set to the same channel. In this case, one wireless AP cannot transmit a beacon signal at the same time as another wireless AP, and is kept waiting for transmission at a fixed interval. As a result, a total of 1 × 10 = 10 milliseconds, that is, 10% of the entire band is consumed for beacon transmission.

  In order to avoid the above-described decrease in communication speed and excessive band consumption due to beacon signals, it is preferable to use different channels. However, as shown in FIG. 1B, the channels overlap each other on the frequency axis. Accordingly, there is only a combination of three channels, such as channels 1, 6, and 11, for example, to select channels that ideally have no overlapping of bands and can communicate stably.

Also in the wireless terminal 1 of the present invention, a channel that is separated from all other channels by a predetermined channel interval or more is determined among the channels associated with the RSSI that is equal to or greater than the predetermined intensity threshold Th _i .

  If a channel separated by a predetermined channel interval (for example, 5) or more cannot be determined, a channel interval (for example, 4) shorter than the predetermined channel interval (for example, 5) is set as a new predetermined channel interval. Is also preferable. In this case, a channel separated by the new channel interval (for example, 4) or more is investigated, and the predetermined channel interval is set to a predetermined interval lower limit value (for example, 2) until a channel separated by the predetermined channel interval or more is determined. ) As a limit and set to smaller values in order.

[Wireless terminal 1]
FIG. 2 is a functional configuration diagram illustrating an embodiment of the wireless terminal 1.

  Referring to FIG. 2, the wireless terminal 1 includes a wireless LAN interface 100, a display / input unit 101, and a processor memory. Here, the processor memory realizes its function by executing a program for causing the computer mounted on the wireless terminal 1 to function.

  Further, the processor memory includes a beacon / response measurement unit 110, an AP information management unit 111, a channel determination unit 12, and a communication control unit 13 as functional configuration units.

  The wireless LAN interface 100 is a communication unit capable of receiving signals including SSID information of these APs and information on channels used by these APs from the APa20, APb21, and APc22. When the RSSI of the beacon including the SSID of the predetermined home AP, which is the SSID, is equal to or greater than the predetermined proximity strength threshold, a probe request (probe request) that is a communication connection inquiry request is transmitted to the APa20. Establish communication connection with.

  The beacon / response measurement unit 110 analyzes the content (SSID, channel, etc.) of a signal (such as a beacon or probe response) received by the wireless LAN interface 100 and measures its RSSI.

  The AP information management unit 111 receives the information of the received signal from the beacon / response measuring unit 110, and for each SSID included in the received signal, the channel used by the signal source AP, the RSSI of this signal, Are recorded and managed in association with each other. Specifically, an AP management table 111t, which will be described later with reference to FIG. 5, is created / updated.

The channel determination unit 12 inputs information of the AP management table 111t,
(A) determine a channel that is separated by a predetermined channel interval R _cn or more from all channels associated with RSSI that is equal to or greater than a predetermined intensity threshold Th _i , or (b) set an RSSI that is equal to or greater than a predetermined intensity threshold Th _i Among the associated channels, a channel separated from all other channels by a predetermined channel interval or more is determined.
Here, (a) extracts and determines unused channels that are separated by 10 from all channels, and (b) extracts and determines channels that are used but separated from others by 10 minutes. It is.

Specifically, the channel determination unit 12 includes an RSSI threshold setting unit 120, a channel interval setting unit 121, and a channel search unit 122. Among, RSSI threshold setting unit 120 sets a predetermined intensity threshold Th _i, if the predetermined channel spacing _{R cn} more spaced channel can not be determined, a new high strength threshold _{Th i + 1} than the intensity threshold Th _i Set to a strong intensity threshold.

The channel search unit 122 investigates a channel separated by a predetermined channel interval R _cn or more based on a channel associated with the RSSI of the new intensity threshold Th _{i + 1} or more, and a channel separated by a predetermined channel interval R _cn or more. The intensity threshold value Th _i is sequentially set to a higher value until is determined.

The channel interval setting unit 121, under a predetermined intensity threshold Th _i, if the predetermined channel spacing R _cn more spaced channel can not be determined, a short channel spacing than the predetermined channel spacing R _cn R _cn '( For example, R _cn −1) is set to a new channel interval.

The channel search unit 122 investigates the channels separated by the new channel interval R _cn ′, and sets the channel interval R _cn to the predetermined interval lower limit value MIN _cn until a channel separated by the new channel interval is determined. Set the limit to a smaller value in order.

  The communication control unit 13 includes a distance determination unit 130, a channel setting unit 131, and a connection control unit 132. Among these, the channel setting unit 131 sets the channel determined by the channel determination unit 12 as a used channel used for communication connection.

  In a situation where the wireless LAN interface 100 is in communication connection with a predetermined home APa 20, the connection control unit 132 sets the channel used for communication connection to the home APa 20 to the channel set by the set channel setting unit 131. Change it.

  At this time, for example, an HTTP (HyperText Transfer Protocol) server unit of the home APa 20 is accessed from a web browser mounted on the wireless terminal 1 and a channel setting / changing web page (Web page) is displayed. The channel used for communication connection with the home APa 20 is changed to the set use channel using this web page. This web page is displayed on the display / input unit 101 which is a touch panel display, for example, and receives a channel change instruction by a user operation.

As a change mode, when the wireless terminal 1 searches for an AP as a new communication connection destination, the channel determination unit 12
(A) Of channels associated with RSSI equal to or greater than a predetermined intensity threshold Th _i , determine a channel that is separated from all other channels by a predetermined channel interval,
The channel setting unit 131
(B) The channel determined by the channel determination unit 12 is set as a channel used for communication connection,
The connection control unit 132
(C) It is also preferable to cause the wireless LAN interface 100 to transmit a probe request, which is a communication connection inquiry request, to a wireless AP having an SSID associated with the used channel set in the AP management table 111t.

The distance determination unit 130 determines whether RSSI such as a beacon / probe response received from a predetermined in-home APa 20 is greater than or equal to a predetermined threshold value I _th when a user having the wireless terminal 1 enters the home from the outside, for example. Determine whether. Then, the automatic connection having the connection control unit 132, when the distance determining unit 130 has performed a true determined (determination that a predetermined threshold _{I th} or higher), the wireless LAN interface 100, the home APa20 A probe request which is an inquiry request for communication connection is transmitted to the address.

  As a change mode, the distance determination unit 130 is based on the arrival time or phase difference of the “electromagnetic wave” or ultrasonic wave output from the home APa 20 in response to the “electromagnetic wave” or ultrasonic wave output from the wireless terminal 1. Alternatively, the distance to the home APa 20 is measured on the basis of the “electromagnetic wave” output from the home APa 20 or the intensity of the received ultrasonic wave, and it is determined whether or not this distance is equal to or less than a predetermined distance threshold. It is also preferable.

  Here, the “electromagnetic wave” can be, for example, a radio wave having a frequency used in infrared, NFC (Near Field Communication), Felica, RFID (Radio Frequency IDentification), or the like.

  In the case of this modification, although not shown, the wireless terminal 1 and / or the home APa 20 includes an “electromagnetic wave” or ultrasonic transmission / reception device, and controls the transmission signal in accordance with the received signal. It has a functional part or a functional part that analyzes the intensity of the received signal.

[Frequency band determination: Channel optimization]
FIG. 3 is a sequence diagram showing an embodiment of a frequency band determination method according to the present invention.

  Here, initially, the wireless terminal 1 is not connected to any AP for communication. Thereafter, as shown in the following sequence, the wireless terminal 1 that has entered the user's home is connected to the home APa 20 that is a predetermined wireless AP, and further obtains information on the surrounding wireless AP, The optimum channel for communication with the APa 20 is determined.

(S300) The communication control unit 13 (wireless LAN interface 100) constantly monitors beacons from surrounding wireless APs in the background.
(S301) The communication control unit 13 (wireless LAN interface 100) transmits a probe request by broadcast in order to obtain information on surrounding wireless APs (APa20, APb21, APc22). During this AP search, probe requests are sequentially transmitted for all of the channels 1 to 14.

(S302) Each of the surrounding wireless APs (APa20, APb21, APc22) responds to the probe request on the channel used by itself, and a probe response (probe response) including its own SSID information and used channel information ) To the wireless terminal 1.
(S303) The AP information management unit 111 inputs the probe response information received by the wireless LAN interface 100.

(S304) The automatic communication connection with the home APa20 is started. The start timing is, for example, when the user who has the wireless terminal 1 enters the home from the outside and determines that the RSSI of the probe response received from the predetermined home APa 20 is equal to or greater than the predetermined threshold value I _th. It is also preferable. At this time, the automatic connection unit of the connection control unit 132 (FIG. 2) causes the wireless LAN interface 100 to transmit a probe request to the home APa 20.
(S305) A communication connection is established between the wireless terminal 1 and the home APa20.

  Note that the authentication information necessary for the automatic connection is stored in the automatic connection unit (connection control unit 132) of the wireless terminal 1 in association with the SSID of the home APa 20, and at the time of this automatic connection, It is also preferred to be called and used.

(S306) The AP information management unit 111 generates an AP management table 111t described later with reference to FIG. 5 from the input probe response information. The AP management table 111t records, for each wireless AP SSID, the channel used by the wireless AP and the RSSI of the probe response (S302) from the wireless AP in association with each other.

(S307, S308) The wireless terminal 1 (communication control unit 13) transmits a connection request as an administrator (Admin) to the home APa20. On the other hand, the home APa 20 transmits an Admin connection response to the wireless terminal 1.
(S309, S310) The wireless terminal 1 (communication control unit 13) transmits an authentication request to the home APa20. On the other hand, the home APa 20 determines the validity of the received authentication information, and transmits an ACK (acknowledgment) for authentication to the wireless terminal 1 when it is determined to be valid.

(S311, S312) The wireless terminal 1 (communication control unit 13) transmits an administrator setting information request for requesting setting information by the administrator to the home APa20. On the other hand, the home APa 20 transmits the administrator setting information to the wireless terminal 1.
(S313) The AP information management unit 111 inputs the administrator setting information received by the wireless LAN interface 100.

(S314) Each of the surrounding wireless APs (APa20, APb21, APc22) periodically transmits a beacon including its own SSID information and used channel information.
(S315) The AP information management unit 111 inputs beacon information received by the wireless LAN interface 100.
(S316) The AP information management unit 111 updates the AP management table 111t based on the input beacon information. For example, in the AP management table 111t, the use channel and RSSI of each wireless AP (SSID) are rewritten to the latest values.

(S317) The AP information management unit 111 outputs the information of the updated AP management table 111t to the channel determination unit 12.
(S318) The channel determination unit 12 determines a channel to be used using the information in the input AP management table 111t. Step S318 will be described in detail later with reference to FIG.

(S319) The channel determination unit 12 outputs the determined channel information to the communication control unit 13.
(S320) The communication control unit 13 changes the setting of the channel used for communication with the home APa 20 to the use channel, using the determined channel as the use channel.

(S321) As a manager, the wireless terminal 1 (communication control unit 13) instructs the home APa 20 to change the setting of the used channel.
(S322) The home APa 20 receives the channel setting change instruction from the wireless terminal 1, and changes the channel used for communication to the instructed use channel.

[Frequency band determination: Wireless AP selection of optimal channel]
FIG. 4 is a sequence diagram showing another embodiment of a frequency band determination method according to the present invention.

  Here, initially, the wireless terminal 1 is not connected to any AP for communication. Thereafter, as shown in the following sequence, the wireless terminal 1 performs an active scan, obtains information on surrounding wireless APs, and establishes a communication connection with the APe 24 that is a wireless AP using an optimal channel among them. .

(S400) The communication control unit 13 (wireless LAN interface 100) constantly monitors beacons from surrounding wireless APs in the background.
(S401) The communication control unit 13 (wireless LAN interface 100) transmits a probe request by broadcast in order to obtain information on surrounding wireless APs (APe24, APf25, APg26). During this AP search, probe requests are sequentially transmitted for all of the channels 1 to 14.

(S402) Each of the surrounding wireless APs (APe24, APf25, APg26) responds to the probe request on the channel used by itself, and a probe response (probe response) including its own SSID information and used channel information ) To the wireless terminal 1.
(S403) The AP information management unit 111 inputs information of the probe response received by the wireless LAN interface 100.

(S404) The AP information management unit 111 generates an AP management table 111t, which will be described later with reference to FIG. 5, from the input probe response information. The AP management table 111t records, for each wireless AP SSID, the channel used by the wireless AP and the RSSI of the probe response (S402) from the wireless AP in association with each other.

(S405) The AP information management unit 111 outputs the information in the AP management table 111t to the channel determination unit 12.
(S406) The channel determination unit 12 determines a channel to be used by using the information of the input AP management table 111t. Step S406 will be described in detail later with reference to FIGS. 6A and 6B.

(S407) The channel determination unit 12 outputs the determined channel information to the communication control unit 13.
(S408) The communication control unit 13 sets the input channel as a use channel, and determines a wireless AP (APe24 in FIG. 4) having an SSID associated with the use channel as a communication connection destination. Here, the setting of the used channel may be set by a user operation via the display / input unit 101, for example.

(S409) The wireless terminal 1 (wireless LAN interface 100) transmits a probe request, which is a communication connection inquiry request, to the wireless AP (APe24) determined as the communication connection destination.
(S410) The APe 24 transmits a probe response to the wireless terminal 1 in response to the received probe request.
(S411) A communication connection is established between the wireless terminal 1 and the home Ape 24.

[AP information table]
FIG. 5 is a schematic diagram showing an embodiment of the AP information table according to the present invention.

In the AP information table 111t illustrated in FIG. 5, for each SSID (ESSID) of the wireless AP existing in the vicinity,
(A) a channel used by the wireless AP;
(B) RSSI of a signal (beacon, probe response, etc.) from which the wireless AP is a transmission source;
(C) The type of the wireless AP is associated and recorded.

Although not shown in the figure, in the AP information table 111t, in association with the SSID (ESSID) of the wireless AP,
(D) BSSID (Basic Service Set Identifier) of the wireless AP
Is also preferably recorded. This BSSID is an identifier of the wireless AP included in the beacon and probe response, and is usually the same as the MAC (Media Access Control) address of the wireless AP.

Here, in (B) RSSI, the received signal strength is divided into five levels, that is,
(A) Excellent (level 5): -50 dBm or more (b) Better (level 4): -60 dBm or more and less than -50 dBm (c) Good (level 3): -70 dBm or more and less than -60 dBm (d ) Not good (level 2): -80 dBm or more and less than -70 dBm (e) Bad (level 1): less than -80 dBm, and any corresponding level is recorded as RSSI.

  Here, radio waves for wireless LAN communication can be effectively received within a distance range of, for example, several tens to hundreds of tens of meters. Therefore, in public spaces such as stations and shopping streets where services related to wireless LAN are enriched, and even in residential spaces such as condominiums, for example, dozens to dozens of wireless APs are rarely detected. is not. Under such an environment, it is almost impossible to find a free channel that is not used in these wireless APs that have received radio waves.

Therefore, the wireless terminal 1 applies an intensity threshold value Th _i to this (B) RSSI to determine an optimum channel. Actually, in the wireless terminal 1, while the strength of the radio wave from the wireless AP is weak, the interference between the radio waves is small. However, as the radio wave strength increases, the interference increases and causes interference. Accordingly, in the AP information table 111t, wireless APs (SSIDs) having (B) RSSI equal to or greater than the strength threshold Th _i are selected, and these (A) channels used by these wireless APs are considered as much as possible ( A) Determine a channel remote from the channel.

  This eliminates, for example, radio waves that do not substantially affect interference (low intensity) even in a situation where there is no empty channel when considering all radio waves, while remaining (high intensity) radio waves that can affect interference. Therefore, it is possible to determine an optimum channel. Hereinafter, a specific method of channel determination will be described.

[Channel determination]
FIG. 6 is a flowchart illustrating an embodiment of channel determination according to the present invention. The channel determination in the figure corresponds to the processing in step S318 in FIG. 3 and step S406 in FIG.

First, in FIG.
(S600) The RSSI filtering loop (S600 to S605) is started. Here, the intensity threshold for RSSI is Th _i (i = 1, 2,..., N _r ), Th ₁ is used in the first loop, and Th ₂ , sequentially in the second and subsequent loops. Th ₃ ,... Are used. Here, Th _i is set such that Th ₁ <Th ₂ <... <Th _nr .
As a specific setting example, Th ₁ = (Not good), Th ₂ = (Good), Th ₃ = (Better), and Th ₄ (= Th _nr ) = (Excellent).

The intensity threshold Th _i (i = 1, 2,..., N _r ) is preferably adjusted according to the environment where the predetermined home APa 20 is installed, for example. For example, in an environment where a large number of wireless AP is present in the near field range of a predetermined home APa20, and the first intensity threshold Th _1, it may be sufficiently high value is set.

(S601) A table FT _i is generated by filtering the AP management table 111t with the intensity threshold Th _i . Specifically, in the AP management table 111t, only a row (column) whose RSSI is equal to or greater than the strength threshold value Th _i is extracted to create a new table FT _i . For example, when the intensity threshold is Th ₁ = (Not good), in FIG. 5, the table FT ₁ in which the third row from the bottom (SSID: Wi2premium) and the second row from the bottom (SSID: Wi2_club) are excluded. Will be generated.

(S602) The channel interval search loop (S602 to S604) is started. Here, channel interval R _cn is set to 5, 4,..., MIN _cn , R _cn = 5 is used in the first loop, and R _cn = 4 _,. , MIN _cn . The interval lower limit value MIN _cn is set to 2, for example.

(S603) determines from all the channels occupied by all the wireless AP in table FT ₁ generated (SSID), whether channels spaced channel spacing _{R cn} above are present.

For example, in the table FT ₁ (in the example described above) in which the third row from the bottom (SSID: Wi2premium) and the second row from the bottom (SSID: Wi2_club) in FIG. 5 are excluded, the channel interval R _cn = 3 In some cases, the channel 14 corresponds to a channel separated by a channel interval R _cn or more, and when the channel interval R _cn = 2, the channels 3, 8, 13 and 14 correspond to channels separated by a channel interval R _cn or more. It will be. In step S603, if one corresponding channel is found, it is preferable to interrupt the channel interval search loop and shift to step S606.

This step S603 is a determination to extract unused channels that are sufficiently separated from all the channels in the table FT ₁ , and information on surrounding wireless APs is stored in a state of being connected to a predetermined wireless AP. Thus, it is adopted when determining an optimum channel in communication with the predetermined wireless AP.

(S606) When a true determination (determination that the corresponding channel exists) is made in step S603, this channel is determined as a use channel, and this flow ends.

(S604) On the other hand, when a false determination is made in step S603, assuming that there is no appropriate channel (separated by a channel interval R _cn or more), the channel interval R _cn is decremented by 1, and step S602 ( Return to the channel interval search loop. However, if the channel interval R _cn = MIN _cn , the channel interval search loop is terminated.

(S605) Suitable channels in the intensity threshold Th _i or absent, the intensity threshold Th _i was incremented by 1, returns to step S600 (RSSI filtering loop). However, if the intensity threshold value is Th _nr , the RSSI filtering loop is terminated, and it is determined that an appropriate channel cannot be determined, and this flow is terminated. Normally, the used channel can be determined by setting the intensity threshold Th _nr to an appropriate (sufficiently large) value.

Next, FIG. 6B shows a change mode (S603 ′) of step S603 described above.
(S603 ′) It is determined whether or not there is a channel that is separated from all other channels by a channel interval R _cn or more among all channels occupied by all the wireless APs (SSIDs) in the generated table FT ₁ To do.

For example, in the table FT ₁ in the third row from the bottom (SSID: Wi2premium) and the second row from the bottom (SSID: Wi2_club) in FIG. 5 (in the example described above), the channel interval R _cn = 5 In some cases, channel 11 (bottom row, SSID: PQ_Wi_Fi) corresponds to a channel separated by a channel interval R _cn or more.

Note that this step S603 ′ is a determination to extract a channel that is sufficiently separated (used) from the others in the table FT ₁ , and obtains information about the surrounding wireless APs, and uses the optimum channel among them. This is adopted when establishing a communication connection with the wireless AP. However, this step S603 ′ is adopted when obtaining information of surrounding wireless APs in a communication connection with a predetermined wireless AP and determining an optimum channel for communication with the predetermined wireless AP. Is also possible.

As described above in detail, in the present invention, the received signal strength (RSSI) and frequency band (channel) of the surrounding wireless AP are monitored, and the received signal strength (RSSI) is equal to or greater than a predetermined strength threshold Th _i. Under these conditions, a frequency band (channel) that is sufficiently separated from the others is selected, and the frequency band (channel) is optimized.

  As a result, the frequency band (channel) with less superposition with the frequency band (channel) in the signal radio wave used in the surrounding wireless AP and having sufficient signal strength to cause interference. ) Can be determined in real time. As a result, a situation in which radio waves for wireless LAN communication interfere can be avoided in real time, and a good communication speed can be maintained.

  In addition, this makes it possible to maintain a good communication connection environment in the wireless LAN, which can contribute to an improvement in the offload rate to the wireless LAN.

  In the various embodiments of the present invention described above, various changes, modifications, and omissions in the technical idea and scope of the present invention can be easily made by those skilled in the art. The above description is merely an example, and is not intended to be restrictive. The invention is limited only as defined in the following claims and the equivalents thereto.

DESCRIPTION OF SYMBOLS 1 Wireless terminal 100 Wireless LAN interface 101 Display / input part 110 Beacon / response measurement part 111 AP (access point) information management part 111t AP management table 12 Channel determination part 120 RSSI threshold value setting part 121 Channel interval setting part 122 Channel search part 13 Communication control unit 130 Distance determination unit 131 Channel setting unit 132 Connection control unit 20, 21, 22, 23, 24, 25, 26 Wireless AP
30, 31, 32 Access network 4 Internet

Claims (10)

A wireless terminal connectable to each of a plurality of wireless access points (APs) via a wireless LAN (Local Area Network),
A wireless LAN interface capable of receiving a signal including connection destination identifier information and frequency band information used by the wireless AP from the wireless AP;
AP information management means for managing the frequency band and the received signal strength of the signal in association with each other for each connection destination identifier included in the received signal;
From all of the frequency bands associated with the received signal strength equal to or greater than the predetermined strength threshold, or from all other frequency bands within the frequency band associated with the received signal strength equal to or greater than the predetermined strength threshold, A frequency band determining means for determining a frequency band separated by a predetermined frequency interval or more;
A wireless terminal comprising: a communication control unit that sets the determined frequency band to a use frequency band used for communication connection. The frequency band determining means sets a higher intensity value than the predetermined intensity threshold as a new intensity threshold when a frequency band separated by more than the predetermined frequency interval cannot be determined, Based on the frequency band associated with the received signal strength, the frequency band separated by the predetermined frequency interval or more is investigated, and the intensity threshold is sequentially set until the frequency band separated by the predetermined frequency interval or more is determined. The wireless terminal according to claim 1, wherein the wireless terminal is used by setting a higher value. The frequency band determining means sets a frequency interval shorter than the predetermined frequency interval to a new frequency interval when the frequency band separated by the predetermined frequency interval or more cannot be determined, and exceeds the new frequency interval. Investigating the separated frequency bands, and using the frequency intervals set to successively smaller values up to a predetermined interval lower limit value until a frequency band separated from the frequency interval is determined. The wireless terminal according to claim 1 or 2. The wireless LAN interface is connected to a predetermined wireless AP among the plurality of wireless APs;
The communication control unit causes the predetermined wireless AP connected in communication to change a frequency band used for the communication connection to the set use frequency band. The wireless terminal according to item.   The wireless LAN interface transmits a communication connection inquiry request to the predetermined wireless AP when the received signal strength of the signal including the connection destination identifier of the predetermined wireless AP is equal to or greater than a predetermined proximity strength threshold. The wireless terminal according to claim 4. Based on the arrival time or phase difference of the electromagnetic wave or ultrasonic wave output from the predetermined wireless AP in response to the electromagnetic wave or ultrasonic wave output from the wireless terminal, or the electromagnetic wave output from the predetermined wireless AP or A distance measurement / determination unit is further provided that measures the distance to the predetermined wireless AP based on the intensity at the time of reception in ultrasonic waves and determines whether the distance is equal to or less than a predetermined distance threshold. And
5. The wireless LAN interface according to claim 4, wherein the wireless LAN interface transmits a communication connection inquiry request to the predetermined wireless AP when a true determination is made by the distance measurement / determination unit. Terminal.   The communication control unit accesses an HTTP (HyperText Transfer Protocol) server unit included in the predetermined wireless AP, and changes a frequency band used for communication connection with the predetermined wireless AP to the set use frequency band. The wireless terminal according to claim 4, wherein the wireless terminal is a wireless terminal. The frequency band determining means determines a frequency band separated from all other frequency bands by the predetermined frequency interval or more among the frequency bands associated with the received signal strength equal to or higher than a predetermined intensity threshold,
The communication control means causes the wireless LAN interface to transmit a communication connection inquiry request to a wireless AP having a connection destination identifier associated with the determined frequency band. 4. The wireless terminal according to any one of items 1 to 3. A frequency band determination program for causing a computer mounted on a wireless terminal connectable to each of a plurality of wireless APs via a wireless LAN,
The wireless terminal includes a wireless LAN interface capable of receiving a signal including connection destination identifier information and frequency band information used by the wireless AP from the wireless AP,
The program is
AP information management means for managing the frequency band and the received signal strength of the signal in association with each other for each connection destination identifier included in the received signal;
From all of the frequency bands associated with the received signal strength equal to or greater than the predetermined strength threshold, or from all other frequency bands within the frequency band associated with the received signal strength equal to or greater than the predetermined strength threshold, A frequency band determining means for determining a frequency band separated by a predetermined frequency interval or more;
A frequency band determination program for causing a computer to function as communication control means for setting the determined frequency band to a use frequency band used for communication connection. A method for determining a frequency band in a wireless terminal connectable to each of a plurality of wireless APs via a wireless LAN,
A first step of receiving a signal including connection destination identifier information and frequency band information used by the wireless AP from the wireless AP;
A second step of managing the frequency band and the received signal strength of the signal in association with each other for each connection destination identifier included in the received signal;
From all of the frequency bands associated with the received signal strength equal to or greater than the predetermined strength threshold, or from all other frequency bands within the frequency band associated with the received signal strength equal to or greater than the predetermined strength threshold, A third step of determining frequency bands separated by a predetermined frequency interval or more;
And a fourth step of setting the determined frequency band to a use frequency band used for communication connection.

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