JP4923278B2 - Wireless LAN system, wireless LAN terminal, and wireless access point selection method used therefor - Google Patents

Description

  The present invention relates to a wireless LAN system, a wireless LAN terminal, a wireless access point selection method used for the wireless LAN system, and a program therefor, and in particular, a wireless LAN (Local Area Network) terminal that performs voice communication is optimal for voice communication from a plurality of wireless base stations. The present invention relates to a method for selecting a wireless access point.

  In the wireless LAN terminal related to the present invention, when a decrease in received radio waves is detected during a call at the start of belonging to a wireless base station, at the start of a call, etc., a plurality of wireless base stations are searched and The received radio signal strength (RSSI: Received Signal Strength Indicator) and the signal-to-noise ratio (SNR: Signal to Noise Ratio) are compared, and an optimal radio base station is selected and connected.

  For example, in the following Patent Document 1, by controlling the permission / non-permission of a call according to the current connection status of a wireless terminal, the deterioration of the call quality of the wireless terminal due to voice packet delay or loss is prevented. A method has been proposed.

  In Patent Document 2, priority is set on the basis of the received radio wave intensity from a radio base station and a PER (Packet Error Rate) value, and priority is selected from access points with higher priority. A method for appropriately selecting a base station is proposed.

JP 2006-279439 A JP 2005-244721 A

  However, in the case of a wireless LAN terminal that handles voice communication, the above-described wireless LAN terminal is optimal for voice communication that requires voice quality and real-time characteristics only by comparing the radio wave intensity and the signal-to-noise ratio. There is a shortage of information for selecting an appropriate radio base station, and as a result, connection to a radio base station whose voice quality is degraded may result in sound quality degradation such as sound interruption or call disconnection.

  Accordingly, an object of the present invention is to solve the above-described problems, and when a wireless LAN terminal that performs voice communication detects a plurality of wireless base stations, the wireless communication system that is optimal for voice communication is based on information from the wireless base station. It is an object of the present invention to provide a wireless LAN system, a wireless LAN terminal, a wireless access point selection method used therefor, and a program thereof that can select a base station as a connection destination.

In the wireless LAN system according to the present invention, a traffic amount is a threshold based on the wireless communication states in a plurality of wireless base stations notified from a communication state acquisition unit that always acquires a wireless communication state with a wireless LAN (Local Area Network) terminal. Traffic determination means for determining whether or not:
Quality comparison means for comparing communication quality in the radio base station;
Voice quality comparison means for comparing voice quality in the radio base station;
The wireless LAN terminal comprises connection permission determining means for determining permission / non-permission of connection to the wireless base station based on the comparison results of the quality comparing means and the voice quality comparing means ,
The wireless base station measures the data transmission amount per second of each of the wireless LAN terminals belonging to the wireless base station as the traffic amount, and calculates free traffic of the wireless base station,
When the wireless LAN terminal has a margin in the free traffic, the priority is determined from the radio field strength, the voice quality from the radio base station with higher priority is compared, and the radio base station with the highest voice quality is compared. Connecting .

In the wireless LAN terminal according to the present invention, the traffic amount is a threshold based on the wireless communication state in a plurality of wireless base stations notified from a communication state acquisition unit that always acquires a wireless communication state with a wireless LAN (Local Area Network) terminal. Traffic determination means for determining whether or not:
Quality comparison means for comparing communication quality in the radio base station;
Voice quality comparison means for comparing voice quality in the radio base station;
Connection permission determining means for determining permission / non-permission of connection to the radio base station based on a comparison result of each of the quality comparison means and the voice quality comparison means ,
The traffic amount is free traffic of the wireless base station calculated by measuring the data transmission amount per second of each of the wireless LAN terminals belonging to the wireless base station,
When there is room in the free traffic, the priority is determined from the radio wave intensity, the voice quality from the radio base station with higher priority is compared, and the connection to the radio base station with the highest voice quality is performed .

A wireless access point selection method according to the present invention includes a wireless LAN system provided with communication state acquisition means for constantly acquiring a wireless communication state with a wireless LAN (Local Area Network) terminal,
A traffic determination process in which the wireless LAN terminal determines whether or not a traffic amount is below a threshold based on the wireless communication states in a plurality of wireless base stations notified from the communication state acquisition means; and the wireless base station Based on the comparison results of the quality comparison process for comparing the communication quality in the voice, the voice quality comparison process for comparing the voice quality in the radio base station, and the quality comparison process and the voice quality comparison process, respectively. Execute connection permission determination processing for determining permission / denial of connection ,
The wireless base station measures the data transmission amount per second of each of the wireless LAN terminals belonging to the wireless base station as the traffic amount, and calculates free traffic of the wireless base station,
When the wireless LAN terminal has a margin in the free traffic, the priority is determined from the radio field strength, the voice quality from the radio base station with higher priority is compared, and the radio base station with the highest voice quality is compared. Connecting .

A program according to the present invention is executed by a computer in a wireless LAN terminal used in a system including a plurality of wireless LAN (Local Area Network) terminals and a plurality of wireless base stations that control wireless communication connections with the wireless LAN terminals. A program to
The system is provided with communication state acquisition means for constantly acquiring a wireless communication state with at least a wireless LAN (Local Area Network) terminal,
A traffic determination process for determining whether or not the traffic volume is below a threshold based on the wireless communication states in the plurality of wireless base stations notified from the communication state acquisition means is compared with the communication quality in the wireless base stations Quality comparison processing, voice quality comparison processing for comparing voice quality at the radio base station, and permission / non-permission of connection to the radio base station based on comparison results of the quality comparison processing and the voice quality comparison processing. viewing including the connection permission determination process for determining the permitted,
The traffic amount is free traffic of the wireless base station calculated by measuring the data transmission amount per second of each of the wireless LAN terminals belonging to the wireless base station,
When the wireless LAN terminal has a margin in the free traffic, the priority is determined from the radio wave intensity, the voice quality from the radio base station with higher priority is compared, and the radio base station with the highest voice quality is compared. The connection is made .

  The present invention has the configuration and operation as described above, and is optimal for voice communication based on information from the radio base station when a wireless LAN terminal that performs voice communication detects a plurality of radio base stations. An effect is obtained that a radio base station can be selected as a connection destination.

  Next, embodiments of the present invention will be described with reference to the drawings. First, an outline of a wireless LAN (Local Area Network) system according to the present invention will be described. FIG. 1 is a block diagram showing a configuration example of a wireless LAN system according to the present invention.

  1, the wireless LAN system according to the present invention includes a plurality of wireless base stations 1 (other wireless base stations other than the wireless base station 1 are not shown) and a wireless LAN terminal 2. The present invention is characterized in that, in the wireless base station 1 and the wireless LAN terminal 2, the wireless LAN terminal 2 that performs voice communication selects a wireless access point that is optimal for voice communication from the plurality of wireless base stations 1. .

  The wireless base station 1 is a wireless base station that controls wireless communication connection with the wireless LAN terminal 2, and includes a communication state acquisition unit 11 that constantly acquires a wireless communication state with the wireless LAN terminal 2, and a communication state acquisition unit 11. A communication state notification unit 12 that notifies the wireless LAN terminal 2 of the acquired wireless communication state.

  The communication status acquisition unit 11 preferably always acquires the traffic amount of the wireless LAN terminal 2 in the wireless base station 1 and the voice quality of the wireless LAN terminal 2 during voice communication. Further, it is preferable that the traffic amount is calculated by measuring the data transmission amount per second of each wireless LAN terminal 2 belonging to the wireless base station 1 and calculating the free traffic of the wireless base station 1. Furthermore, it is preferable that the above voice quality is obtained by measuring the voice quality of each wireless LAN terminal 2 belonging to the radio base station 1 and calculating the average value of the whole.

  As the communication state notifying unit 12, it is preferable to use a management packet [Beacon (beacon), Probe (probe), etc.] standardized by IEEE (Institut of Electric and Electrical Engineers) 802.11.

  The beacon is a frame that is periodically transmitted to notify the function that the operating wireless base station 1 supports to the wireless LAN terminal 2 and the ID (SSID: Service Set IDentifier) of BSA (Basic Service Area). It is. The probe is a frame to be transmitted when the reception state of radio waves from the wireless base station 1 becomes worse while the wireless LAN terminal 2 is in operation.

  The wireless LAN terminal 2 compares the communication quality in the wireless base station 1 with the traffic determination unit 21 that determines whether or not the traffic amount is equal to or less than the threshold based on the wireless communication state notified from the wireless base station 1. Based on the comparison results of the quality comparison unit 22, the voice quality comparison unit 23 that compares the voice quality in the radio base station 1, and the quality comparison unit 22 and the voice quality comparison unit 23, permission / denial of connection to the radio base station 1 is determined. And a connection permission determining unit 24 that determines permission.

  The quality comparison unit 22 preferably uses a received signal strength indicator (RSSI) or a signal-to-noise ratio (SNR) of a received signal from the radio base station 1.

  The voice quality comparison unit 23 described above is the voice quality [R value: ITU-T (International Telecommunication Union-Telecommunication Standardization Sector) G. It is preferable to use [defined in 107].

  Here, the R value is the G.D. This is a value calculated from sound quality, delay, echo, etc. according to the E-model calculation formula 107. E-model is a tool for estimating various parameters that determine the conversation quality of a telephone service using a handset.

The R value is calculated by measuring individual parameters of the R value, Ro: line noise, transmitter / receiver room noise, subscriber line noise, Is: OLR (loudness), side tone, quantization distortion, Id: speaker Echo, listener echo, total delay, Ie, eff: low bit rate coding, packet / cell loss,
R = Ro-Is-Id-Ie, eff + A
It is done with the formula. A in the above formula is an item representing convenience, and is a specified value (A = 0).

  Regarding the calculation of the R value, the G.I. By using the BASIC source code of 107 Annex C [5], the calculation can be performed only by preparing an R value parameter. A tool for calculating the R value simply by inputting the R value parameter is also commercially available.

  Based on the comparison result of the quality comparison unit 22 / voice quality comparison unit 23, the connection permission determination unit 24 permits the connection to the radio base station 1 depending on whether the communication quality of the radio base station 1 is equal to or higher than a threshold value. It is preferable to determine non-permission.

  In the wireless LAN system according to the present invention, the communication quality maintaining unit (not shown) that acquires the wireless communication state in the established communication from the communication state acquisition unit 11 and switches the connection according to the acquired wireless communication state. Is preferably provided in the wireless LAN terminal 2.

  The communication quality maintaining unit requests connection to another connectable wireless base station when the wireless communication state acquired by the communication state acquisition unit 11 is equal to or less than a predetermined threshold, and the acquired wireless communication state Is not more than a predetermined threshold value, and it is preferable to notify the warning information when there is no other connectable radio base station.

  As described above, the present invention enables the wireless LAN terminal 2 to determine the connection to the wireless base station 1 based on the voice quality information (R value) in addition to the radio wave intensity, so that the wireless base station 1 optimum for voice communication is used. Can be selected.

  Further, in the present invention, when the wireless LAN terminal 2 has enough free traffic detected in the wireless base station 1, the priority is determined from the radio wave intensity, and the voice quality from the wireless base station 1 having a higher priority is determined. In comparison, connection is made to the radio base station 1 with the highest voice quality.

  2 is a block diagram showing a configuration example of the wireless LAN system according to the embodiment of the present invention, FIG. 3 is a block diagram showing a configuration example of the wireless base station of FIG. 2, and FIG. 4 is a wireless LAN system of FIG. It is a block diagram which shows the structural example of a terminal.

  2, a wireless LAN system 100 includes wireless base stations 1a, 1b that control wireless communication connections between wireless LAN terminals 2a, 2b, 2c,... And wireless LAN terminals 2a, 2b, 2c,. ,... And a system control device 3 that performs various controls in communication at the radio base stations 1a, 1b,.

  In the wireless LAN system 100, as shown in FIG. 2, wireless base stations 1a, 1b,... (AP: access point) are connected to the system control device 3, and the wireless base stations 1a, 1b,. The wireless LAN terminals 2a, 2b, 2c,.

  The system control device 3 performs various controls in communication as the wireless LAN system 100, such as handover between a plurality of wireless base stations 1a, 1b,.

  The wireless base stations 1a, 1b,... Have an antenna 10 for performing wireless communication with the wireless LAN terminals 2a, 2b, 2c,. A wired communication unit 14 for performing wired communication between the wireless communication unit 13 and the system control device 3 and the like, and a control unit 15 for controlling the entire wireless base station 1 [for example, a CPU (central processing unit), etc. , And the storage unit 16 for storing the number of belongings and traffic volume of the wireless LAN terminals 2a, 2b, 2c,... And the wireless quality for storing the voice quality of the wireless LAN terminals 2a, 2b, 2c,. And a storage unit 16a.

  The wireless LAN terminals 2a, 2b, 2c,... Have an antenna 20 for performing wireless communication with the wireless base stations 1a, 1b,. A wireless communication unit 25, a communication control unit 26 that performs communication control such as transmission output by the wireless communication unit 25, a control unit 27 (for example, a CPU) that controls the entire wireless communication terminal 2, the wireless base station 1 a, 1b,... For storing voice quality and traffic volume, a display unit 29 for displaying various types of information, an operation input unit 30 for receiving operation input from the user, and a voice call. The receiver 31 and the transmitter 32 are provided. The storage unit 28 is provided with a priority determination table 28a.

  The processing operations of the communication state acquisition unit 11 and the communication state notification unit 12 of the radio base station 1 shown in FIG. 1 are realized by the control unit 15 of the radio base station 1 executing a program stored in the storage unit 16. Is possible. The processing operations of the traffic determination unit 21, the quality comparison unit 22, the voice quality comparison unit 23, and the connection permission determination unit 24 of the wireless LAN terminal 2 illustrated in FIG. 1 are performed by the control unit 27 of the wireless LAN terminal 2 in the storage unit 28. This can be realized by executing the stored program.

  FIG. 5 is a flowchart showing the operation before the connection of the wireless LAN terminal 2 of FIG. 3 is established, and FIG. 6 is a flowchart showing the operation before the connection of the wireless base station 1 of FIG. FIG. 7 is a flowchart showing an operation during communication connection after the connection of the wireless LAN terminal 2 of FIG. 3 is established.

  8 is a diagram showing an example of the priority determination table 34a in FIG. 4, and FIG. 9 is a diagram showing an example of a warning notification screen by the wireless LAN terminal 2 in FIG. The operation of the wireless LAN terminal 2 selecting the wireless base station 1 optimal for voice communication will be described with reference to FIGS. 5 and 7 is realized by the control unit 27 of the wireless LAN terminal 2 executing a program stored in the storage unit 28, and the process shown in FIG. 6 is performed by the control of the wireless base station 1. This is realized by the unit 15 executing the program stored in the storage unit 16.

  When the wireless base station 1 receives the connection request from the wireless LAN terminal 2, the wireless base station 1 determines the sound quality, the voice quality (R value: E-model, the sound quality, (Calculated from delay, echo, etc.) is stored in the wireless quality storage unit 16a and periodically notified to the wireless LAN terminal 2 (step S16 in FIG. 6).

  As the calculation method, as shown in FIG. 6, the wireless base station 1 has the number of wireless LAN terminals 2 belonging to the own station (step S11 in FIG. 6), the amount of free traffic (step S12 in FIG. 6), voice Quality (R value) (step S15 in FIG. 6) is constantly monitored. Regarding the voice quality, if there is no wireless LAN terminal 2 in a call, the average value of the voice quality for a certain period in the past is calculated (step S14 in FIG. 6).

  The control unit 27 of the wireless LAN terminal 2 receives information related to the radio field strength (RSSI) of the signal of the wireless base station 1 by the wireless communication unit 25 in addition to the free traffic amount and the R value calculated as described above. (Step S1 in FIG. 5), the information is stored in the storage unit 28, and information indicating whether or not the radio base station 1 is connectable is acquired (Step S2 in FIG. 5).

  The control unit 27 of the wireless LAN terminal 2 does not have enough free traffic amount to connect the wireless LAN terminal 2 to the wireless base station 1 for the connection capability of the wireless LAN terminal 2 (step S3 in FIG. 5; NO) or when there is no other connectable radio base station 1, the communication is disconnected (step S4 in FIG. 5).

  The control unit 27 of the wireless LAN terminal 2 determines the priority of the wireless base station 1 based on the radio field intensity by referring to the priority determination table 28a as shown in FIG. FIG. 5 step S5).

  The control unit 27 of the wireless LAN terminal 2 compares the voice quality (R value) from the radio base station 1 with a high priority, and connects to the radio base station 1 with the same priority and the highest voice quality (R value). (Step S6 in FIG. 5).

  FIG. 8 shows an example of a priority determination table 28a for determining the priority according to the radio wave intensity in the received signal from the radio base station. In FIG. 8, the priority determination table 28a stores the radio wave intensity [dBm] and the priority in association with each other.

  In the priority determination table 28a, if the radio wave intensity [dBm] is “−40 or more”, the priority is “high”, and if the radio wave intensity [dBm] is “−70 or more and less than −40”, If the priority is “medium” and the radio wave intensity [dBm] is “less than −70”, it is stored that the priority is “low”.

  The operation during the voice communication after the connection is thus established will be described with reference to the flowchart of FIG.

  Even after the connection is established, the control unit 27 constantly acquires information on the radio field intensity, voice quality (R value), and available traffic volume of the radio base station 1 from the radio communication unit 25. When the radio field intensity and the voice quality (R value) are each equal to or higher than a predetermined quality threshold value and there is a surplus in the amount of available traffic (steps S21, S22, and S23 in FIG. 7; YES), the control unit 27 remains as it is. Continue communication.

  When either the radio field intensity or the R value is less than a predetermined quality threshold, or the amount of free traffic is less than a predetermined quality threshold, the control unit 27 (steps S21, S22, S23 in FIG. 7). NO), the wireless LAN terminal 2 requests a handover to another wireless base station having a voice quality (R value) that is equal to or higher than a predetermined quality threshold for the wireless base station 1, and the wireless base station 1 inquires of the system control apparatus 3 whether it can be handed over to another radio base station (step S24 in FIG. 7).

  When the handover is possible, the control unit 27 hands over the communication between the wireless LAN terminal 2 and the wireless base station 1 (step S25 in FIG. 7).

  When the handover is impossible, the control unit 27 continues the communication with the radio base station 1 as it is, but it is possible that the voice quality may be affected by the decrease in the radio field strength, the R value, etc. 9 is displayed on the display unit 29 (for example, “*** Warning *** The sound quality has deteriorated due to the deterioration of the radio wave environment!”) Or by the voice of the speaker of the receiver 31. The user is notified (step S26 in FIG. 7).

  As described above, in the present embodiment, by using information in the system, communication data, and the like received by the wireless LAN terminal 2, it is most suitable for voice communication when there are a plurality of connectable wireless base stations 1. The radio base station 1 can be selected.

  In the present embodiment, the information (communication data) in the system is used during the call of the wireless LAN terminal 2 to automatically ensure the voice quality suitable for the use environment. Warning).

  Furthermore, in the present embodiment, when any one of the radio field intensity, the signal-to-noise ratio, and the R value is lowered to a predetermined quality threshold value, the wireless LAN terminal 2 outputs a warning sound / warning display. The user can be prompted to move to handover to the optimal radio base station 1, or the user can be prompted not to move further when handover is not desired.

  In the present invention, in the above embodiment, the R value is used as the measurement parameter of the voice quality information. However, the R value is not limited to this R value as long as it is a criterion for determining the voice quality. Even if PESQ (Perceptual Evaluation Speech Quality) (defined in P.862 of ITU-T), which is a voice call quality test, is implemented in the same manner as described above.

  Here, PESQ is a P.Q. This is a method for estimating the listening quality defined in 862, in which a voice sample is prepared and the original sound is compared with the sound after passing through the evaluated system.

  In the present invention, in the above embodiment, the radio field intensity of the received signal is used as the priority standard of the radio base station. In addition to this, the signal-to-noise ratio, the packet retransmission rate, and the like are added to the determination standard. It is also possible.

  Furthermore, according to the present invention, in the above embodiment, the system control device 3 and the wireless base station 1 are communicated with each other by wire. However, the present invention is not limited to this as long as communication is possible. Good.

  Furthermore, according to the present invention, in the above embodiment, the means and functions provided in the wireless base station 1 may be realized as the entire wireless communication system 100, for example, the system control apparatus 3 may be provided.

It is a block diagram which shows the structural example of the wireless LAN system by this invention. It is a block diagram which shows the structural example of the wireless LAN system by embodiment of this invention. FIG. 3 is a block diagram illustrating a configuration example of a radio base station in FIG. 2. It is a block diagram which shows the structural example of the wireless LAN terminal of FIG. 4 is a flowchart showing an operation before the connection of the wireless LAN terminal of FIG. 3 is established. It is a flowchart which shows the operation | movement before the connection of the wireless base station of FIG. 3 is established. 4 is a flowchart showing an operation during communication connection after the connection of the wireless LAN terminal of FIG. 3 is established. It is a figure which shows an example of the priority determination table of FIG. FIG. 5 is a diagram showing an example of a warning notification screen by the wireless LAN terminal 2 of FIG. 4.

Explanation of symbols

1, 1a, 1b Wireless base station 2, 2a, 2b, 2c Wireless LAN terminal
3 System controller
10,20 antenna
11 Communication status acquisition unit
12 Communication status notifier
13, 25 Wireless communication unit
14 Wired communication section
15, 27 Control unit
16, 28 storage unit
16a Wireless quality storage unit
21 Traffic judgment part
22 Quality Comparison Department
23 Voice quality comparison section
24 Connection permission decision unit
26 Communication control unit
28a Priority determination table
29 Display section
30 Operation input section
31 Earpiece
32 Speaker
100 Wireless LAN system

Claims (24)

It is determined whether or not the traffic amount is below a threshold based on the wireless communication states in a plurality of wireless base stations notified from a communication state acquisition unit that constantly acquires a wireless communication state with a wireless LAN (Local Area Network) terminal. Traffic judgment means to
Quality comparison means for comparing communication quality in the radio base station;
Voice quality comparison means for comparing voice quality in the radio base station;
Have a connection permission determining means for determining permission / non-permission of the connection to the wireless base station on the basis of the quality comparison means and the voice quality comparison means each of the comparison result to the wireless LAN terminal,
The wireless base station measures the data transmission amount per second of each of the wireless LAN terminals belonging to the wireless base station as the traffic amount, and calculates free traffic of the wireless base station,
When the wireless LAN terminal has a margin in the free traffic, the priority is determined from the radio field strength, the voice quality from the radio base station with higher priority is compared, and the radio base station with the highest voice quality is compared. A wireless LAN system characterized by performing connection .   The wireless LAN system according to claim 1, wherein the communication state acquisition unit constantly acquires the traffic amount of the wireless LAN terminal and the voice quality of the wireless LAN terminal during voice communication as the wireless communication state. The wireless LAN system according to claim 1 , wherein the voice quality is obtained by measuring a voice quality of each of the wireless LAN terminals belonging to the wireless base station and calculating an average value of the whole. . Examples voice quality, at least the sound quality, delay, wireless LAN system according to any one of claims 1 to 3, characterized by using the R value calculated from the echo. The connection permission determining means permits / denies connection to the radio base station depending on whether or not the voice quality from the radio base station is equal to or higher than a threshold based on the comparison result of the voice quality comparing means. wireless LAN system according to any one of claims 1 to 4, characterized in that the determining. The wireless LAN terminal includes communication quality maintaining means for acquiring a wireless communication state in communication already established from the wireless base station and switching connection with the wireless base station according to the acquired wireless communication state. wireless LAN system according to any one of claims 1 to 5, wherein. The communication quality maintaining means requests a connection to another connectable radio base station when the radio communication state acquired from the radio base station is equal to or less than a predetermined threshold, and acquires the radio acquired from the radio base station. 7. The wireless LAN system according to claim 6 , wherein warning information is notified when the communication state is equal to or less than a predetermined threshold and there is no other connectable wireless base station . Wherein the communication state acquiring unit, from claim 1, characterized in that provided on either the system control device that performs various control in a wireless communication including a handover between the radio base station and at least said plurality of radio base stations Item 8. The wireless LAN system according to any one of items 7 . It is determined whether or not the traffic amount is below a threshold based on the wireless communication states in a plurality of wireless base stations notified from a communication state acquisition unit that constantly acquires a wireless communication state with a wireless LAN (Local Area Network) terminal. Traffic judgment means to
Quality comparison means for comparing communication quality in the radio base station;
Voice quality comparison means for comparing voice quality in the radio base station;
Connection permission determining means for determining permission / non-permission of connection to the radio base station based on a comparison result of each of the quality comparison means and the voice quality comparison means,
The traffic amount is free traffic of the wireless base station calculated by measuring the data transmission amount per second of each of the wireless LAN terminals belonging to the wireless base station,
When there is room in the free traffic, the priority is determined from the radio wave intensity, the voice quality from the radio base station with higher priority is compared, and the connection to the radio base station with the highest voice quality is performed. A wireless LAN terminal. The wireless LAN terminal according to claim 9, wherein the wireless communication state includes a traffic amount of the wireless LAN terminal and a voice quality of the wireless LAN terminal during voice communication. The wireless LAN terminal according to claim 9 or 10, wherein the voice quality is obtained by measuring a voice quality of each of the wireless LAN terminals belonging to the wireless base station and calculating an average value of the whole. . The wireless LAN terminal according to any one of claims 9 to 11, wherein an R value calculated from at least sound quality, delay, and echo is used as the voice quality. The connection permission determining means permits / denies connection to the radio base station depending on whether or not the voice quality from the radio base station is equal to or higher than a threshold based on the comparison result of the voice quality comparing means. 13. The wireless LAN terminal according to claim 9, wherein the wireless LAN terminal is determined. 10. A communication quality maintaining unit that acquires a wireless communication state in communication already established from the wireless base station and switches connection with the wireless base station according to the acquired wireless communication state. The wireless LAN terminal according to claim 13. The communication quality maintaining means requests a connection to another connectable radio base station when the radio communication state acquired from the radio base station is equal to or less than a predetermined threshold, and acquires the radio acquired from the radio base station. 15. The wireless LAN terminal according to claim 14, wherein the warning information is notified when the communication state is equal to or less than a predetermined threshold and there is no other connectable wireless base station. A wireless LAN system is provided with communication state acquisition means for constantly acquiring a wireless communication state with a wireless LAN (Local Area Network) terminal,
A traffic determination process in which the wireless LAN terminal determines whether or not a traffic amount is below a threshold based on the wireless communication states in a plurality of wireless base stations notified from the communication state acquisition means; and the wireless base station Based on the comparison results of the quality comparison process for comparing the communication quality in the voice, the voice quality comparison process for comparing the voice quality in the radio base station, and the quality comparison process and the voice quality comparison process, respectively. Execute connection permission determination processing for determining permission / denial of connection,
The wireless base station measures the data transmission amount per second of each of the wireless LAN terminals belonging to the wireless base station as the traffic amount, and calculates free traffic of the wireless base station,
When the wireless LAN terminal has a margin in the free traffic, the priority is determined from the radio field strength, the voice quality from the radio base station with higher priority is compared, and the radio base station with the highest voice quality is compared. A wireless access point selection method characterized by performing connection. The wireless access point selection method according to claim 16, wherein the communication state acquisition means constantly acquires the traffic amount of the wireless LAN terminal and the voice quality of the wireless LAN terminal during voice communication as the wireless communication state. . The wireless access point according to claim 16 or 17, wherein the voice quality is obtained by measuring a voice quality of each of the wireless LAN terminals belonging to the wireless base station and calculating an average value of the whole. Selection method. The radio access point selection method according to any one of claims 16 to 18, wherein an R value calculated from at least sound quality, delay, and echo is used as the voice quality. In the connection permission determination process, permission / non-permission of connection to the radio base station is determined based on whether the voice quality from the radio base station is equal to or higher than a threshold based on the comparison result of the voice quality comparison process. 20. The wireless access point selection method according to claim 16, wherein the wireless access point selection method is determined. The wireless LAN terminal acquires a wireless communication state in already established communication from the wireless base station, and executes communication quality maintenance processing for switching connection with the wireless base station according to the acquired wireless communication state The wireless access point selection method according to any one of claims 16 to 20, wherein: In the communication quality maintenance process, when the wireless communication state acquired from the wireless base station is equal to or less than a predetermined threshold, a request for connection to another connectable wireless base station is made, and the wireless acquired from the wireless base station The wireless access point selection method according to claim 21, wherein warning information is notified when the communication state is equal to or less than a predetermined threshold and there is no other connectable wireless base station. 17. The system according to claim 16, wherein the communication state acquisition unit is provided in any of system control devices that perform various controls in radio communication including handover between the radio base station and at least the plurality of radio base stations. Item 23. The method for selecting a wireless access point according to any one of Items 22. A program to be executed by a computer in a wireless LAN terminal used in a system including a plurality of wireless LAN (Local Area Network) terminals and a plurality of wireless base stations that control wireless communication connections with the wireless LAN terminals,
The system is provided with communication state acquisition means for constantly acquiring a wireless communication state with at least a wireless LAN (Local Area Network) terminal,
A traffic determination process for determining whether or not the traffic volume is below a threshold based on the wireless communication states in the plurality of wireless base stations notified from the communication state acquisition means is compared with the communication quality in the wireless base stations Quality comparison processing, voice quality comparison processing for comparing voice quality at the radio base station, and permission / non-permission of connection to the radio base station based on comparison results of the quality comparison processing and the voice quality comparison processing. A connection permission determination process for determining permission,
The traffic amount is free traffic of the wireless base station calculated by measuring the data transmission amount per second of each of the wireless LAN terminals belonging to the wireless base station,
When the wireless LAN terminal has a margin in the free traffic, the priority is determined from the radio wave intensity, the voice quality from the radio base station with higher priority is compared, and the radio base station with the highest voice quality is compared. A program characterized by making a connection.

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