JP2016192729A - Radio base station device, radio communication system, and radio base station device control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dynamically determine a channel enabling higher quality radio communication.SOLUTION: A base station 10 comprises: a storage unit 115; two radio interfaces W1 and W2; a radio communication unit 111 for using a communication interface 112, which is any one of the two radio interfaces W1 and W2, to perform radio communication with a communication terminal on one channel and to acquire a communication state; a state acquisition unit 113 for using a monitoring interface 114, which is the other of the two radio interfaces W1 and W2, during radio communication by the radio communication unit 111 to acquire a radio wave state around the base station 10 and to store the acquired radio wave state in the storage unit 115; a determination unit 116 for determining a suitable channel on the basis of the communication state acquired by the radio communication unit 111 and the radio wave state stored in the storage unit 115; and a control unit 117 for performing control so that the radio communication unit 111 performs radio communication with the communication terminal on the suitable channel by using the monitoring interface 114.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a radio base station apparatus, a radio communication system, and a control method for the radio base station apparatus.

  Conventionally, a wireless communication terminal (hereinafter also referred to as a communication terminal) and a wireless base station device (hereinafter also referred to as a base station) that communicates with the communication terminal via a wireless communication link (hereinafter also referred to as a communication link) are used. A conventional WLAN (Wireless Local Area Network) is used. The communication terminal can communicate with another communication device (such as a Web server or a mail server) on a network connected to the WLAN via the WLAN.

  In wireless communication, the communication success rate is generally improved by avoiding collision of communication frames. However, if there is an external wave having the same frequency band as the frequency band (hereinafter also referred to as a channel) of radio waves used for radio communication, radio radio waves are disturbed and communication fails. In addition, if the amount of communication is large, the possibility of collision of communication frames increases, and the throughput decreases due to an increase in waiting time for collision avoidance. Therefore, in order to maintain high throughput of wireless communication, it is desirable to select a channel with as few external waves as possible and with less communication by other communication terminals.

  Patent Document 1 discloses a communication method between a base station equipped with two wireless interfaces and a communication terminal. According to this technique, communication data is transmitted and received by one of the two wireless interfaces, and a decryption key for the communication data is transmitted by the other. Thereby, it is possible to perform encrypted communication while suppressing a decrease in communication amount.

JP 2012-060443 A

  However, in order to select a channel capable of high-quality wireless communication, such as few external waves or other communication terminals, specialized equipment and knowledge of wireless communication are required. In addition, the state of wireless communication may change dynamically with a period of several hours or days. It is practically difficult to determine a channel through which wireless communication with high quality can be performed after analyzing such changes in the situation.

  The present invention has been made to solve the above problem, and an object of the present invention is to provide a radio base station apparatus and the like that dynamically determine a channel capable of radio communication with higher quality.

  In order to solve the above-described problem, a radio base station apparatus according to an aspect of the present invention is a radio base station apparatus, and is a storage unit, two radio interfaces, or one of the two radio interfaces. The first interface is used to perform wireless communication with a communication terminal through one channel, a wireless communication unit that acquires a communication state of the one channel, and the two wireless interfaces during wireless communication by the wireless communication unit Using the second interface, which is the other of the radio base station apparatus, acquires a radio wave condition around the radio base station device, and stores the acquired radio wave condition in the storage unit and the radio communication unit. Based on the communication status and the radio wave status stored in the storage unit, it is estimated that wireless communication with higher quality than wireless communication using the one channel can be performed. That includes a determining unit for determining a preferred channel, and a control unit for the radio communication section is controlled to perform the communication terminal and the wireless communication by the preferred channel using the second interface.

  According to this, a radio base station apparatus acquires surrounding radio wave conditions using another radio interface that is not used for this radio communication while performing radio communication with a communication terminal using one radio interface. And when a suitable channel is defined based on the acquired radio wave condition, it is possible to perform channel switching so that wireless communication with the communication terminal is performed using the suitable channel. In addition, when the communication terminal performs channel switching, both the wireless interface that operates in the channel that performs wireless communication and the wireless interface that operates in the preferred channel exist. Communication interruption time can be shortened as much as possible. Therefore, the radio base station apparatus can dynamically determine a channel capable of radio communication with higher quality.

  In addition, when the control unit controls the wireless communication unit to perform wireless communication using the second interface, the state acquisition unit further acquires a radio wave state using the first interface. The acquired radio wave status is controlled to be stored in the storage unit.

  According to this, when the wireless communication on the preferred channel is started, the wireless base station device uses the wireless interface used for the wireless communication before the channel switching, and the wireless interface for acquiring the surrounding radio wave status. Used as In this way, the radio base station apparatus reverses the roles of the two radio interfaces with those before channel switching, thereby continuously acquiring surrounding radio wave conditions, determining a suitable channel, and switching the channel to the preferred channel. It can be performed.

  In addition, when the determination unit determines the suitable channel, the determination unit further determines a start time of wireless communication on the suitable channel by the second interface, and the control unit further determines the suitable channel by the second interface. Wireless communication is started at the start time.

  According to this, the radio base station apparatus can perform channel switching to a suitable channel in a time zone where there is little radio communication with the communication terminal according to the purpose of use of radio communication. As a result, it is possible to suppress the influence of wireless communication interruption time associated with channel switching.

  In addition, when performing wireless communication on the preferred channel using the second interface, the wireless communication unit notifies that the wireless communication channel is switched to the preferred channel prior to the start of the wireless communication. A notification signal is transmitted to a communication terminal that is performing wireless communication.

  According to this, the radio base station apparatus can give an opportunity of channel switching to the communication terminal by wireless communication, and the communication terminal can perform channel switching using the received notification signal as an opportunity.

  The wireless communication unit, when transmitting the notification signal, causes the first interface to notify the second interface of key information necessary for wireless communication with the communication terminal based on a request from the communication terminal. .

  According to this, the radio base station apparatus can notify key information used in radio communication on the preferred channel prior to communication on the preferred channel. Thereby, it is possible to omit the exchange of the key information based on the key information before starting the wireless communication on the suitable channel, and it is possible to start the wireless communication on the suitable channel in a short time.

  Further, when acquiring the radio wave status, the status acquisition unit acquires the radio wave status a plurality of times as time passes in each channel that the radio base station apparatus can use for radio communication while changing the channel. The determination unit may determine that a wireless communication bandwidth occupancy obtained from the radio wave situation acquired a plurality of times stored in the storage unit is smaller than a wireless communication bandwidth occupancy obtained from the communication situation. The channel that has continued for more than the time is determined as the preferred channel.

  According to this, the radio base station apparatus can continuously acquire the radio wave status of each usable channel by the radio interface that is not used for radio communication. Then, the radio base station apparatus can appropriately determine a suitable channel based on the radio wave status acquired over a relatively long time, such as several hours or days, and the communication status of radio communication. it can.

  In addition, the determination unit further includes (a) wireless communication using the one channel based on the communication status acquired by the wireless communication unit and the radio wave status stored in the storage unit. (B) if the candidate channel is included in a frequency band in which a weather radar wave may exist, the presence / absence of a weather radar wave in the candidate channel is determined. And (c) when a weather radar wave is not detected in the candidate channel, the candidate channel is determined as a preferred channel.

  According to this, when using a channel included in a frequency band in which weather radar waves can exist as a preferred channel, the radio base station apparatus appropriately determines a preferred channel using the two radio interfaces, The wireless communication interruption time associated with switching can be shortened as much as possible.

  Further, a radio communication system according to an aspect of the present invention performs radio communication on the one channel with the radio base station apparatus and the radio communication unit using the first interface of the radio base station apparatus, After the wireless communication unit is controlled to use the second interface, the wireless communication unit includes the wireless communication unit that uses the second interface and the communication terminal that performs wireless communication on the preferred channel.

  According to this, a radio | wireless communications system has an effect similar to said radio base station apparatus.

  A radio base station apparatus control method according to an aspect of the present invention is a radio base station apparatus control method, wherein the radio base station apparatus includes a storage unit and two radio interfaces, and the control The method performs wireless communication with a communication terminal using a first interface which is one of the two wireless interfaces, and acquires a communication status of the one channel; and During wireless communication in the wireless communication step, using the second interface, which is the other of the two wireless interfaces, acquires a radio wave condition around the radio base station device, and stores the acquired radio wave condition in the storage unit Based on the status acquisition step of storing, the communication status acquired in the wireless communication step, and the radio wave status stored in the storage unit, Determining a suitable channel estimated to be capable of wireless communication with higher quality than wireless communication using a channel; and performing wireless communication with the communication terminal on the suitable channel using the second interface in the wireless communication step. And a control step for performing control.

  According to this, the radio base station apparatus has the same effect as the radio base station apparatus described above.

  Note that the present invention can be realized not only as an apparatus but also as a method using steps as processing units constituting the apparatus, as a program for causing a computer to execute the steps, or as a computer read recording the program. It can also be realized as a possible recording medium such as a CD-ROM, or as information, data or a signal indicating the program. These programs, information, data, and signals may be distributed via a communication network such as the Internet.

  The radio base station apparatus according to the present invention can dynamically determine a channel capable of radio communication with higher quality.

FIG. 1 is a configuration diagram of a radio communication system including a base station according to Embodiment 1. FIG. 2 is a block diagram showing a hardware configuration of the base station according to the first embodiment. FIG. 3 is a block diagram showing a functional configuration of the base station according to Embodiment 1. FIG. 4 is an explanatory diagram of a band occupancy rate that is an example of the radio wave status acquired by the status acquisition unit according to the first embodiment. FIG. 5 is an explanatory diagram of a frame capture log that is an example of the radio wave status acquired by the status acquisition unit according to the first embodiment. FIG. 6 is an explanatory diagram of an example of the analysis result of the frame capture log according to the first embodiment. FIG. 7 is a flowchart showing processing of the base station according to Embodiment 1. FIG. 8 is a sequence diagram illustrating a connection switching method in the wireless communication system according to the first embodiment. FIG. 9 is a block diagram showing a hardware configuration of the base station according to the second embodiment. FIG. 10 is a block diagram illustrating a functional configuration of the base station according to the second embodiment. FIG. 11 is a flowchart showing processing of the base station according to Embodiment 2. FIG. 12 is a sequence diagram illustrating a connection switching method in the wireless communication system according to the second embodiment.

  Hereinafter, embodiments will be specifically described with reference to the drawings.

  Each of the embodiments described below shows a preferred specific example of the present invention. The numerical values, shapes, materials, constituent elements, arrangement positions and connecting forms of the constituent elements, steps, order of steps, and the like shown in the following embodiments are merely examples, and are not intended to limit the present invention. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are described as optional constituent elements that constitute a more preferable embodiment.

  In addition, the same code | symbol is attached | subjected to the same component and description may be abbreviate | omitted.

(Embodiment 1)
In this embodiment, a radio base station apparatus and a radio communication system capable of dynamically determining a channel capable of radio communication with higher quality will be described. In the wireless communication system according to the present embodiment, after dynamically determining a channel capable of wireless communication with higher quality, wireless communication between the wireless base station apparatus and the communication terminal is performed on the determined channel. Further, when the communication terminal is compatible, it is possible to shorten the communication interruption time associated with channel switching to a channel capable of wireless communication with higher quality.

  FIG. 1 is a configuration diagram of a wireless communication system 1 including a base station 10 according to the present embodiment.

  As shown in FIG. 1, the wireless communication system 1 includes a base station 10 and a communication terminal 20. The wireless communication system 1 is connected to a LAN 30 (Local Area Network) and a network 40.

  The base station 10 is a radio base station apparatus that performs radio communication with the communication terminal 20. The base station 10 includes a wireless interface, establishes a communication link with the communication terminal 20 existing in the wireless communicable area, and performs wireless communication. Further, the base station 10 is connected to the LAN 30 and transfers the communication frame toward the destination according to the destination of the communication frame (communication packet) used for wireless communication. Note that the wireless communication is realized by a wireless LAN that conforms to, for example, the IEEE 802.11a, b, g, and n standards.

  The base station 10 includes two wireless interfaces W1 and W2, and appropriately uses them to find a channel capable of wireless communication with higher quality, and perform wireless communication with the communication terminal 20 using the discovered channel. . The method of using the two wireless interfaces W1 and W2 will be described in detail later.

  The communication terminal 20 is a wireless communication terminal having a wireless interface. The communication terminal 20 establishes a communication link with either the wireless interface W1 or W2 included in the base station 10 and performs wireless communication. The communication terminal 20 can communicate with another communication device (not shown) connected to the LAN 30 or the network 40 via the base station 10.

  When the communication terminal 20 is compatible with so-called high-speed handover technology (hereinafter also referred to as “fast handover”), the connection of the communication link from one of the radio interfaces W1 and W2 to the other is switched. It is also possible to shorten the accompanying communication interruption time. The fast handover technology includes, for example, the IEEE 802.11r standard.

  The LAN 30 is a communication network (local area network) connected to the base station 10 and the network 40. The LAN 30 is realized by a wired LAN that conforms to, for example, the IEEE 802.3 standard.

  The network 40 is an external communication network connected to the LAN 30. The network corresponds to, for example, an access network in a telecommunications carrier or the Internet.

  The hardware configuration and functional configuration of the base station 10 in the wireless communication system 1 configured as described above will be described.

  FIG. 2 is a block diagram showing a hardware configuration of base station 10 according to the present embodiment.

  As shown in FIG. 2, the base station 10 includes a CPU 101 (Central Processing Unit), a ROM 102 (Read Only Memory), a main memory 103, a storage 104, and wireless interfaces W1 and W2.

  The CPU 101 is a processor that executes a control program stored in the ROM 102 or the storage 104.

  The ROM 102 is a read-only storage area that holds a control program and the like.

  The main memory 103 is a volatile storage area used as a work area used when the CPU 101 executes a control program.

  The storage 104 is a non-volatile storage area that holds a control program, content, and the like.

  The wireless interface W1 is a wireless communication interface that establishes a communication link with the communication terminal 20 and performs wireless communication. The wireless interface W1 is a wireless LAN communication interface conforming to, for example, the IEEE802.11a, b, g, and n standards, and includes a wireless communication signal generation circuit, an antenna, and the like. As will be described later, the wireless interface W1 is used as a communication interface for wireless communication or a monitoring interface for acquiring a radio wave condition around the base station 10. A predetermined SSID (Service Set Identifier) is set in the wireless interface W1.

  The wireless interface W2 is a wireless communication interface having the same hardware configuration as the wireless interface W1, and is used in the same application as the wireless interface W1. The wireless interface W2 operates independently of the wireless interface W1. The same SSID as the wireless interface W1 is set in the wireless interface W2.

  Note that the antenna of the radio interface W1 and the antenna of the radio interface W2 are provided in a housing of one base station 10, and are arranged with an interval of, for example, about 10 cm.

  FIG. 3 is a block diagram showing a functional configuration of base station 10 according to the present embodiment.

  As illustrated in FIG. 3, the base station 10 includes a wireless communication unit 111, a communication interface 112, a status acquisition unit 113, a monitoring interface 114, a storage unit 115, a determination unit 116, and a control unit 117. With.

  The wireless communication unit 111 is a processing unit that performs wireless communication with the communication terminal 20. Specifically, the wireless communication unit 111 establishes a communication link with the communication terminal 20 through the communication interface 112 and transmits / receives a communication frame to / from the communication terminal 20 through the established communication link. As the communication interface 112, one or both of the wireless interfaces W1 and W2 are dynamically used. The control unit 117 determines at which timing the wireless communication unit 111 uses the wireless interfaces W1 and W2 as the communication interface 112. The wireless communication unit 111 is realized by the CPU 101, the ROM 102, the main memory 103, and the like (hereinafter also referred to as the CPU 101).

  Further, the wireless communication unit 111 provides the determination unit 116 with a communication status of a channel (hereinafter also referred to as “communication channel”) used by the communication interface 112 for wireless communication. The communication status is information including the bandwidth occupancy rate of wireless communication in the communication channel, the number of frames transmitted / received (at least one of transmission and reception) by the communication interface 112, and the like.

  The channel used for wireless communication with the communication terminal 20 is changed from one wireless interface used by the wireless communication unit 111 as the communication interface 112 to the other wireless interface among the wireless interfaces W1 and W2. This is realized when the terminal 20 performs connection switching. At this time, if the other wireless interface is set to a channel capable of wireless communication with higher quality before connection switching, wireless communication can be performed on that channel by the connection switching. Become. For this connection switching, a high-speed handover technique can be used.

  In addition, the channel change is performed by the communication terminal 20 voluntarily stopping another wireless interface by stopping the operation (for example, transmission of radio waves) of one of the wireless interfaces used by the wireless communication unit 111 as the communication interface 112. It may be realized by searching for an interface. The channel change may be performed when the wireless communication unit 111 transmits a notification signal for channel switching to the communication terminal 20 and the communication terminal 20 receives the notification signal. As the notification signal, for example, CSA (Channel Switch Announcement) defined by the IEEE 802.11h standard can be used.

  The communication interface 112 is a wireless interface used by the wireless communication unit 111 to establish and maintain a communication link with the communication terminal 20. One or both of the wireless interfaces W1 and W2 are dynamically used as the communication interface 112 based on control by the control unit 117.

  The status acquisition unit 113 is a processing unit that acquires radio wave conditions around the base station 10 during wireless communication by the radio communication unit 111 and stores the acquired radio wave conditions in the storage unit 115. Specifically, the status acquisition unit 113 acquires the radio wave status a plurality of times with the passage of time in each channel that can be used for wireless communication while changing the channel by the monitoring interface 114. For example, the status acquisition unit 113 acquires the radio wave status in one of the channels that can be used for wireless communication for 500 msec, and then acquires the radio wave status in the same manner in another channel that can be used for wireless communication. By performing this for all channels that can be used for wireless communication, the radio wave status of each channel that can be used for wireless communication is acquired. In addition, the status acquisition unit 113 repeatedly acquires the radio wave status described above, so that the radio wave status in all channels that can be used for wireless communication over a long period of time (for example, several hours, several days, or more). Is stored in the storage unit 115.

  The radio wave status acquired by the status acquisition unit 113 is, for example, a band occupation rate for each channel, a frame capture log, or a noise floor value of external noise. As the monitoring interface 114, one of the wireless interfaces W1 and W2 is dynamically used. The control unit 117 determines which timing of the wireless interfaces W1 and W2 the status acquisition unit 113 uses as the monitoring interface 114. The situation acquisition unit 113 is realized by the CPU 101 or the like.

  The monitoring interface 114 is a wireless interface that is used by the status acquisition unit 113 and acquires the radio wave status around the base station 10. One of the wireless interfaces W1 and W2 is dynamically used as the monitoring interface 114 based on control by the control unit 117.

  The storage unit 115 is a storage device that stores radio wave conditions around the base station 10 as a status history 121. The status history 121 is history data in which the radio wave status acquired by the status acquisition unit 113 is stored as time series data, and is read and used by the determination unit 116. The storage unit 115 is realized by the storage 104.

  Based on the communication status acquired by the wireless communication unit 111 and the radio wave status (situation history 121) stored in the storage unit 115, the determination unit 116 can perform wireless communication with higher quality than the wireless communication on the communication channel. It is a processing part which determines the suitable channel which is an estimated channel. Specifically, the determination unit 116 acquires the communication status of the communication channel from the wireless communication unit 111. Further, the determination unit 116 is a radio wave situation (situation history 121) stored in the storage unit 115, and a band occupancy rate or a frame capture log (hereinafter referred to as “capture log”) for each channel that can use the wireless interfaces W1 and W2. Is also read out from the storage unit 115. Then, based on the communication status and the radio wave status, a suitable channel, which is a channel that is estimated to be capable of wireless communication with a higher quality rate, is determined. A specific determination method will be described in detail later.

  Note that when determining the preferred channel, the determination unit 116 may further determine the start time of wireless communication on the preferred channel. As the start time, for example, it is assumed that a time included in a time zone in which radio communication with a communication terminal is small is set according to the purpose of use of radio communication. As a result, it is possible to suppress the influence of wireless communication interruption time associated with channel switching.

  The control unit 117 is a processing unit that controls a wireless interface used by each of the wireless communication unit 111 and the status acquisition unit 113. Specifically, when the determination unit 116 determines a preferred channel, the control unit 117 controls the monitoring interface 114 to operate as a new communication interface 112 that performs wireless communication on the preferred channel. . In addition, the control unit 117 controls the wireless interface used as the communication interface 112 to newly operate as the monitoring interface 114 in the above case.

  In addition, when the determination unit 116 determines the start time together with the preferred channel, the control unit 117 performs control so that the operation of the new communication interface 112 is started at the start time.

  For example, in the control unit 117, the wireless communication unit 111 performs wireless communication using the wireless interface W <b> 1 as the communication interface 112, and the situation acquisition unit 113 uses the wireless interface W <b> 2 as the monitoring interface 114. When the preferred channel is determined in a state where the wireless communication unit 111 is acquired, the wireless communication unit 111 starts wireless communication using the preferred channel using the wireless interface W2, and the situation acquisition unit 113 uses the wireless interface W1. Control to start acquisition of radio wave conditions.

  Next, the radio wave status acquired by the status acquisition unit 113 will be described with reference to two specific examples. The first specific example is a band occupation ratio for each channel, and the second specific example is a capture log.

  FIG. 4 is an explanatory diagram of a band occupancy rate that is an example of the radio wave status acquired by the status acquisition unit 113 according to the present embodiment. (A), (b), and (c) of FIG. 4 are graphs showing the bandwidth occupancy rates at different times for each channel.

  For example, the graph shown in FIG. 4A shows the channel bandwidth occupancy rate, such that the channel 1 bandwidth occupancy is about 83% and the channel 2 bandwidth occupancy is about 61%. From this graph, it is determined that the channel occupancy rate around the channels 1 and 8 is relatively high, and the channel occupancy around the channels 4 and 11 is relatively low.

  From the graphs of FIGS. 4B and 4C, a channel having a relatively low band occupancy rate or a channel having a relatively high bandwidth occupancy rate is determined based on the same idea as described above.

  The determination part 116 determines a suitable channel as follows using the band occupation rate shown by FIG. For example, the bandwidth occupancy rate of each channel acquired three times at predetermined time intervals within a predetermined time is (a), (b), and (c) in FIG. 4, and the bandwidth of the communication channel of the communication interface 112 Assume that the occupation ratio is about 30%. At this time, from (a), (b), and (c) of FIG. 4, the determination unit 116 determines a channel whose bandwidth occupancy is continuously 30% or less within a predetermined time. As a result of the determination, the determination unit 116 selects the channel 11 as a channel whose band occupation ratio is continuously 30% or less, and determines the preferred channel as the channel 11.

  FIG. 5 is an explanatory diagram of a capture log that is an example of the radio wave status acquired by the status acquisition unit 113 according to the present embodiment.

  The capture log shown in FIG. 5 shows information related to a plurality of communication frames acquired by the monitoring interface 114. For each of the plurality of communication frames, a time 501, a source address 502, a destination address 503, a communication Each information of the channel 504 and the frame length 505 is included.

  The time 501 is information indicating the time when the monitoring interface 114 acquires the communication frame. The time 501 may be an absolute indication of the time, or may be a relative indication of the time. The time 501 is based on the time of the oldest communication frame on the capture log, for example, and the time from the time of the oldest communication frame as a reference to the reception time of the communication frame, that is, relative to the time as the reference The time is set. Note that the minimum unit of time when the time 501 is measured is about 1 microsecond to 1 millisecond.

  The transmission source address 502 is information indicating the transmission source MAC address of the communication frame. In FIG. 4, “MAC (A1)” means the MAC address of the base station A1 (not shown), and “MAC (S1)” means the MAC address of the communication terminal S1 (not shown). To do. Note that the MAC address is generally expressed as a 12-digit hexadecimal number such as “11: 22: 33: aa: bb: cc”.

  The destination address 503 is information indicating the destination MAC address of the communication frame. The contents described are the same as those for the transmission source address 502.

  The communication channel 504 is information indicating the channel from which the communication frame is acquired.

  The frame length 505 is information indicating the frame length of the communication frame.

  The determination unit 116 determines a suitable channel as follows by analyzing the capture log shown in FIG.

  FIG. 6 is an explanatory diagram of an example of the analysis result of the capture log according to the present embodiment.

  As shown in FIG. 6, the analysis result of the capture log includes the number of terminals 601 and the number of base stations 602 communicating on each channel, the number of communication frames 603 and the amount of communication data 604 ( The unit includes, for example, [kbps].

  A method for calculating the number of terminals 601 and the number of base stations 602 will be described below. In the following description, an address means a MAC address.

  From the transmission source address 502 and the destination address 503 included in the capture log, it is not known whether the address is a terminal address or a base station address. Therefore, in order to know that the address is the address of the terminal or the base station, the determination unit 116 supports a pair of the transmission source address 502 and the destination address 503 of each communication frame in a plurality of communication frames in the capture log. Based on this association, it is determined whether the address is for the terminal or the base station. Specifically, the determination unit 116 determines that the address included in one of the pair is relatively high as the base station address. In this method, the base station 10 transfers communication frames exchanged between other communication devices connected to the LAN 30 and the communication terminal 20, so that the base station address is included in one of the above pairs. This is a method that utilizes the fact that the frequency increases naturally.

  In the above description, when determining whether the frequency is high, the determination may be made based on a result of comparing the frequency with a predetermined value. Also, an appropriate value that can distinguish the base station from other communication devices based on the frequency distribution may be determined as the predetermined value.

  When there is a predetermined address as the base station or terminal address, it may be determined whether the address is for the base station or the terminal using the address.

  A method for calculating the number of communication frames 603 and the amount of communication data 604 will be described below.

  The communication frame number 603 is obtained as the number of communication frames acquired from a specific channel in the capture log. The communication data amount 604 is obtained by extracting only frames acquired from a specific channel from the capture log, and then transmitting communication data per unit time based on the transmission / reception time (time 501) of each frame and the frame length 505. It is obtained by calculating the amount.

  The determination unit 116 determines a channel in which the number of terminals 601, the number of base stations 602, the number of communication frames 603, or the communication data amount 604 is a predetermined value or less. And the determination part 116 determines the channel obtained as a result of determination as a suitable channel. When determining a suitable channel, each of the number of terminals 601, the number of base stations 602, the number of communication frames 603, and the amount of communication data 604 may be comprehensively evaluated and used. Any one or more analysis results may be used. In addition, when there are a plurality of suitable channels determined using the band occupancy rate as described above, it is also effective to narrow down the suitable channels in consideration of the number of terminals 601 and the like.

  The operation of the base station 10 configured as described above will be described below.

  FIG. 7 is a flowchart showing processing of base station 10 according to the present embodiment.

  With the communication terminal 20 establishing a communication link with the wireless interface W1 as the communication interface 112, the base station 10 performs the following processing, so that the communication terminal 20 communicates with the wireless interface W2. Is established.

  In step S <b> 101, the determination unit 116 acquires the communication status of the communication channel from the wireless communication unit 111.

  In step S <b> 102, the determination unit 116 acquires the status history 121 as the radio wave situation around the base station 10 from the storage unit 115.

  In step S103, the determination unit 116 determines a suitable channel using the communication status acquired in step S101 and the radio wave status acquired in step S102.

  In step S104, the wireless communication unit 111 transmits a CSA to the communication terminal 20 as a notification signal for channel switching from the communication channel to the preferred channel.

  In step S105, the wireless communication unit 111 causes the wireless interface W1 to notify the wireless interface W2 of key information in accordance with an instruction from the communication terminal 20. Specifically, when receiving a key information notification request from the communication terminal 20, the wireless communication unit 111 performs control so that the wireless interface W1 notifies (passes) the key information to the wireless interface W2. Thus, the function of notifying key information used for wireless communication with a wireless interface to other wireless interfaces is realized by a high-speed handover technique.

  In step S106, the control unit 117 controls the wireless communication unit 111 to use the wireless interface W2 used as the monitoring interface 114 as the new communication interface 112.

  In step S107, the communication terminal 20 switches the connection of the communication link from the wireless interface W1 to the wireless interface W2. Connection switching is performed by the communication terminal 20 disconnecting the communication link with the wireless interface W1 and establishing the communication link with the wireless interface W2. Note that this connection switching takes about 50 msec according to the fast handover technique. On the other hand, according to a normal handover technique (conventional handover technique that is not a fast handover technique), this connection switching is performed by scanning a channel for searching for a connection destination base station (several seconds, more specifically, In addition to about 1 to 3 seconds), the communication terminal 20 requires about 200 msec for authentication or the like necessary for connection of a communication link with the wireless interface W2.

  In step S108, the wireless interface W1 notifies the wireless interface W2 of the completion of switching.

  In step S <b> 109, the control unit 117 controls the status acquisition unit 113 to use the wireless interface W <b> 1 used as the communication interface 112 as the new monitoring interface 114.

  Through the series of processes described above, the base station 10 can dynamically determine a channel capable of wireless communication with high quality, and the base station 10 and the communication terminal 20 can perform wireless communication on the determined channel.

  Note that the CSA transmission in step S104 is not an essential processing step of the present invention. When the CSA is not transmitted, the base station 10 does not execute the process of step S105 because the communication terminal 20 is not given an opportunity to exchange key information for new wireless communication. In this case, the communication terminal 20 maintains a communication link with the wireless interface W1 until the wireless interface W1 is used as the monitoring interface 114 in step S108. When the wireless interface W1 is started to be used as the monitoring interface 114 in step S108, the communication link is disconnected, and wireless communication using the same SSID as the SSID used for wireless communication with the wireless interface W1 is provided. The wireless interface W2 is found by searching for the wireless interface that is being used, and a communication link with the wireless interface W2 is established. In this case, the time required for connection switching is longer than in the case of performing the process of step S104, but the object of the present invention is achieved.

  Note that the exchange of key information in step S105 is not an essential processing step in the present invention. That is, when the communication terminal 20 does not support the fast handover technique, step S105 is not performed. In that case, the communication terminal 20 switches connection from the radio interface W1 to the radio interface W2 using a normal handover technique. In this case, the time required for connection switching is longer than in the case of performing step S105, but the object of the present invention is achieved.

  FIG. 8 is a sequence diagram showing a connection switching method in radio communication system 1 according to the present embodiment. The processes described in FIG. 7 are denoted by the same reference numerals, and detailed description thereof is omitted.

  First, it is assumed that the communication terminal 20 has not established a communication link with any wireless interface, and the base station 10 uses the wireless interface W1 as the communication interface 112.

  When the communication terminal 20 establishes a communication link with the base station 10 (wireless interface W1), first, the communication terminal 20 scans a channel. Channel scanning generally takes about several seconds, more specifically, about 1-3 seconds. Further, after channel scanning, authentication (authentication), connection (association), and exchange of key information (4-way handshake) are performed between the communication terminal 20 and the wireless interface W1. These exchanges generally require about 200 msec. After this exchange, wireless communication between the communication terminal 20 and the base station 10 becomes possible.

  Here, if the control unit 117 performs a process of determining a suitable channel (step S103), the CSA is transmitted from the base station 10 to the communication terminal 20. When receiving the CSA, the communication terminal 20 requests the radio interface W1 to perform the fast handover technique between the radio interface W1 and the radio interface W2. Upon receiving this request, the wireless communication unit 111 notifies key information for wireless communication from the wireless interface W1 to the wireless interface W2 (step S105).

  When the wireless interface W2 starts to be used as the communication interface 112, the communication terminal 20 disconnects the communication link with the wireless interface W1 and establishes the communication link with the wireless interface W2 to establish a communication link with the wireless interface W2. Then, authentication (Authentication) and connection (Association) are performed. These exchanges generally require about 50 msec.

  After the communication terminal establishes a communication link with the wireless interface W2, the wireless interface W2 notifies the wireless interface W1 of the completion of switching. Based on this notification, the status acquisition unit 113 newly acquires the radio wave status around the base station 10 using the wireless interface W1 as the monitoring interface 114.

  When the wireless interface W1 is newly used as the monitoring interface 114, the status acquisition unit 113 continues to store the acquired radio wave status history in the status history 121. By doing in this way, the missing period of the history data on the status history 121 can be shortened.

  In addition, since the base station 10 is equipped with two radio interfaces W1 and W2 in one base station 10, the following advantages are obtained.

  First, at the time of channel switching, there is an advantage that a change in the physical position of the antenna of the radio interface is small, and a change in communication characteristics accompanying the channel switching can be suppressed to a small level. In a normal use state, it is considered that the base station 10 and the communication terminal 20 are often arranged at a distance of about several meters. When the distance between the antennas of the wireless interfaces W1 and W2 is 10 cm, when viewed from the communication terminal 20, the antenna appears to move about 10 cm by channel switching. However, the antenna moving distance of 10 cm can be regarded as having no substantial movement as compared with the distance between the base station 10 and the communication terminal 20.

  Second, there is an advantage that the surrounding radio wave condition can be acquired in a short time by using two wireless interfaces together. When the base station 10 is arranged, it may be desired to acquire in advance the radio wave condition at the position where the base station 10 is to be arranged. In that case, acquisition of the radio wave condition is completed in half the time compared with the case of using one radio interface by using both of the two radio interfaces and acquiring the radio wave condition in different channels. Can do.

  As described above, the radio base station apparatus according to the present embodiment performs radio communication with a communication terminal using one radio interface, and uses other radio interfaces that are not used for this radio communication. Get the status. And when a suitable channel is defined based on the acquired radio wave condition, it is possible to perform channel switching so that wireless communication with the communication terminal is performed using the suitable channel. In addition, when the communication terminal performs channel switching, both the wireless interface that operates in the channel that performs wireless communication and the wireless interface that operates in the preferred channel exist. Communication interruption time can be shortened as much as possible. Therefore, the radio base station apparatus can dynamically determine a channel capable of radio communication with higher quality.

  In addition, when wireless communication on a suitable channel is started, the wireless base station device uses the wireless interface used for wireless communication before channel switching as a wireless interface for acquiring surrounding radio wave conditions. In this way, the radio base station apparatus reverses the roles of the two radio interfaces with those before channel switching, thereby continuously acquiring surrounding radio wave conditions, determining a suitable channel, and switching the channel to the preferred channel. It can be performed. The wireless base station device uses the wireless interface used for wireless communication before channel switching as a wireless interface for acquiring surrounding radio wave conditions when wireless communication on a preferred channel is started. In this way, the radio base station apparatus reverses the roles of the two radio interfaces with those before channel switching, thereby continuously acquiring surrounding radio wave conditions, determining a suitable channel, and switching the channel to the preferred channel. It can be performed.

  In addition, the radio base station apparatus can perform channel switching to a suitable channel in a time zone in which radio communication with a communication terminal is low according to the purpose of use of radio communication. As a result, it is possible to suppress the influence of wireless communication interruption time associated with channel switching.

  Also, the radio base station apparatus can give a channel switching opportunity to the communication terminal by wireless communication, and the communication terminal can switch the channel using the received notification signal as a trigger.

  Further, the radio base station apparatus can notify key information used in radio communication on the preferred channel prior to communication on the preferred channel. Thereby, it is possible to omit the exchange of the key information based on the key information before starting the wireless communication on the suitable channel, and it is possible to start the wireless communication on the suitable channel in a short time.

  Also, the radio base station apparatus can continuously acquire the radio wave status of each usable channel using the radio interface that is not used for radio communication. Then, the radio base station apparatus can appropriately determine a suitable channel based on the radio wave status acquired over a relatively long time, such as several hours or days, and the communication status of radio communication. it can.

(Embodiment 2)
In this embodiment, a radio base station apparatus and a radio communication system capable of dynamically determining a channel capable of radio communication with higher quality will be described. In the present embodiment, in particular, a radio base station apparatus that appropriately determines a channel when a channel capable of radio communication with higher quality is a channel included in a frequency band in which radio waves for other purposes may exist The wireless communication system will be described. Note that the same components as those in Embodiment 1 are denoted by the same reference numerals, and detailed description thereof may be omitted.

  The radio communication system according to the present embodiment has the same system configuration (FIG. 1) as radio communication system 1 in the first embodiment. However, the radio communication system 1 differs from the radio interface in the control method of the radio interface.

  FIG. 9 is a block diagram showing a hardware configuration of base station 10A according to the present embodiment.

  As illustrated in FIG. 9, the base station 10A includes wireless interfaces W1A and W2A. Other components are the same as the components having the same names in the first embodiment, and thus detailed description thereof is omitted.

  Similarly to the wireless interface W1, the wireless interface W1A is a wireless communication interface that establishes a communication link with the communication terminal 20 and performs wireless communication. The frequency band in which the wireless interface W1A performs wireless communication includes a frequency band in which radio waves for other purposes may exist. The frequency band in which radio waves for other purposes may exist is, for example, IEEE802.11a (frequency band in which radio waves used by weather radar (hereinafter also referred to as “weather radar waves”) may exist. W53), and this case will be described below as an example.

  When the radio interface W1A uses a channel included in a frequency band in which a weather radar wave may exist, the radio interface W1A receives radio waves on the channel for 1 minute when starting to use the channel, and the weather radar It is stipulated to confirm that no waves are detected. The wireless interface W1A can perform wireless communication on the channel only when a weather radar wave is not detected on the channel for one minute. This is determined in order to avoid interference with weather radar waves.

  Note that a conventional base station having only one radio interface is at least one minute above (if a weather radar wave is detected during this one minute, another one minute for reception on another channel) Communication is not possible, which is a major operational problem. The base station 10A of the present embodiment also has an advantage that this problem can be avoided.

  The wireless interface W2A is a wireless communication interface having the same hardware configuration as the wireless interface W1A, and is used for the same application as the wireless interface W1A. The wireless interface W2A operates independently of the wireless interface W1A.

  FIG. 10 is a block diagram showing a functional configuration of base station 10A according to the present embodiment.

  As illustrated in FIG. 10, the base station 10A includes a status acquisition unit 113A and a determination unit 116A. Other components are the same as those in the base station 10 in the first embodiment.

  The situation acquisition unit 113A is a processing unit that acquires the radio wave situation around the base station 10A and stores the acquired radio wave situation in the storage unit 115, similar to the situation acquisition unit 113 in the first embodiment.

  In addition, when the determination unit 116A determines a candidate channel described later, the situation acquisition unit 113A monitors a weather radar wave in the candidate channel and notifies the determination unit 116A whether or not a weather radar wave has been detected.

  The determination unit 116A determines a candidate channel by the same method as the method for determining the preferred channel in the first embodiment. Then, the weather radar wave is monitored in the candidate channel using the situation acquisition unit 113A and the monitoring interface 114. When a weather radar wave is not detected in the candidate channel, the candidate channel is determined as a preferred channel. When a weather radar wave is detected in the candidate channel, the determination unit 116A determines another candidate channel and monitors the weather radar wave in the candidate channel, and selects a candidate channel in which the weather radar wave is not detected. Repeat until discovered.

  FIG. 11 is a flowchart showing processing of the base station according to the present embodiment. The same processing steps as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  In step S201, the determination unit 116A determines a candidate channel using the communication status acquired in step S101 and the radio wave status acquired in step S102. The method for determining the candidate channel is the same as the method for determining the preferred channel in step S103 of the first embodiment. When step S201 is executed again after a weather radar wave is detected in step S203, which will be described later, candidate channels are determined by excluding channels in which the weather radar wave is detected.

  In step S202, the determination unit 116A causes the weather radar wave to be monitored in the candidate channel using the situation acquisition unit 113A and the monitoring interface 114.

  In step S <b> 203, the situation acquisition unit 113 </ b> A determines whether a weather radar wave is detected by the monitoring interface 114. If a weather radar wave is detected (Yes in step S203), step S201 is performed again. If no weather radar wave is detected (No in step S203), the process proceeds to step S204.

  In step S204, the determination unit 116A determines a candidate channel for which a weather radar wave has not been detected in step S203 as a preferred channel.

  Thereafter, by the processing in steps S104 to S109, communication with the communication terminal 20 can be performed in a channel capable of wireless communication with higher quality.

  In this way, when the communication interface 112 is performing wireless communication, the monitoring interface 114 monitors the weather radar wave, and after confirming that no weather radar wave is detected, performs channel switching. be able to. Therefore, the base station 10A can perform wireless communication with higher quality even when the channel capable of wireless communication with higher quality is a channel included in a frequency band in which radio waves for other purposes may exist. Can be determined appropriately.

  FIG. 12 is a sequence diagram showing a connection switching method in radio communication system 1A according to the present embodiment. The processes described in FIGS. 8 and 11 are denoted by the same reference numerals, and detailed description thereof is omitted.

  As shown in FIG. 12, the radio interface W2 as the monitoring interface 114 monitors weather radar waves when the radio interface W1 as the communication interface 112 is performing radio communication. Accordingly, wireless communication between the base station 10A and the communication terminal 20 can be performed with higher quality without causing a period during which the base station 10A and the communication terminal 20 cannot perform wireless communication for monitoring the weather radar wave. Appropriate channels can be determined appropriately.

  As described above, the radio base station apparatus according to the present embodiment uses the two radio interfaces as appropriate channels when the channels included in the frequency band in which weather radar waves can exist are used as the preferred channels. And the wireless communication interruption time associated with channel switching can be shortened as much as possible.

  As described above, the radio base station apparatus of the present invention has been described based on the embodiment. However, the present invention is not limited to this embodiment. Unless it deviates from the meaning of this invention, the form which carried out the various deformation | transformation which those skilled in the art can think to this embodiment, and the structure constructed | assembled combining the component in different embodiment is also contained in the scope of the present invention. .

  The radio base station apparatus of the present invention can dynamically determine a channel capable of radio communication with higher quality. Specifically, it can be used for a radio base station apparatus in an office, a factory, a house, or the like.

1, 1A wireless communication system 10, 10A base station 20 communication terminal 30 LAN
40 network 101 CPU
102 ROM
103 main memory 104 storage 111 wireless communication unit 112 communication interface 113, 113A status acquisition unit 114 monitoring interface 115 storage unit 116, 116A determination unit 117 control unit 121 status history W1, W1A, W2, W2A wireless interface

Claims (9)

A wireless base station device,
A storage unit;
Two wireless interfaces;
A wireless communication unit that performs wireless communication with a communication terminal in one channel using a first interface that is one of the two wireless interfaces, and acquires a communication status of the one channel;
During radio communication by the radio communication unit, a radio wave condition around the radio base station device is acquired using a second interface which is the other of the two radio interfaces, and the acquired radio wave condition is stored in the storage unit. A status acquisition unit to store;
Based on the communication status acquired by the wireless communication unit and the radio wave status stored in the storage unit, it is presumed that wireless communication with higher quality than wireless communication using the one channel can be estimated. A determination unit for determining a channel;
A radio base station apparatus comprising: a control unit that controls the radio communication unit to perform radio communication with the communication terminal on the preferred channel using the second interface. The controller is
When the wireless communication unit is controlled to perform wireless communication using the second interface, the status acquisition unit further acquires a radio wave status using the first interface, and acquires the acquired radio wave status. The radio base station apparatus according to claim 1, wherein the radio base station apparatus is controlled to be stored in the storage unit. When the determining unit determines the suitable channel, the determining unit further determines a start time of wireless communication on the suitable channel by the second interface,
The radio base station apparatus according to claim 1, wherein the control unit starts radio communication on the preferred channel by the second interface at the start time. The wireless communication unit
When performing wireless communication on the preferred channel using the second interface, prior to the start of the wireless communication, a notification signal for notifying that the channel of wireless communication is to be switched to the preferred channel is provided. The radio base station apparatus according to any one of claims 1 to 3, wherein the radio base station apparatus transmits to a communication terminal. The wireless communication unit
The wireless base according to claim 4, wherein when the notification signal is transmitted, key information necessary for wireless communication with the communication terminal is notified from the first interface to the second interface based on a request from the communication terminal. Station equipment. When acquiring the radio wave status, the status acquisition unit acquires the radio wave status multiple times as time elapses in each channel that the radio base station device can use for radio communication while changing the channel.
The determination unit is configured such that a wireless communication bandwidth occupancy obtained from the radio wave situation acquired a plurality of times stored in the storage unit is smaller than a wireless communication bandwidth occupancy obtained from the communication situation for a predetermined time or more. The radio base station apparatus according to claim 1, wherein a continuing channel is determined as the preferred channel. The determination unit further includes:
(A) Based on the communication state acquired by the wireless communication unit and the radio wave state stored in the storage unit, it is estimated that wireless communication with higher quality than wireless communication using the one channel can be performed. (B) when the candidate channel is included in a frequency band in which a weather radar wave can exist, the situation acquisition unit is monitored for the presence or absence of the weather radar wave in the candidate channel. (C) The radio base station apparatus according to any one of claims 1 to 6, wherein the candidate channel is determined as a preferred channel when a weather radar wave is not detected in the candidate channel. The radio base station apparatus according to any one of claims 1 to 7,
After the radio communication unit that uses the first interface of the radio base station apparatus performs radio communication in the one channel, and the radio communication unit is controlled to use the second interface, A wireless communication system comprising: the wireless communication unit that uses an interface; and the communication terminal that performs wireless communication on the preferred channel. A control method for a radio base station apparatus,
The wireless base station device
A storage unit;
With two wireless interfaces,
The control method is:
Using the first interface that is one of the two wireless interfaces, performing wireless communication with a communication terminal in one channel, and obtaining a communication status of the one channel; and
During wireless communication in the wireless communication step, using the second interface, which is the other of the two wireless interfaces, acquires a radio wave condition around the radio base station device, and the acquired radio wave condition is stored in the storage unit A status acquisition step to store in
Based on the communication status acquired in the wireless communication step and the radio wave status stored in the storage unit, it is estimated that radio communication with higher quality than radio communication using the one channel can be performed. A decision step for determining a channel;
A control step of performing control so as to perform wireless communication with the communication terminal on the preferred channel using the second interface in the wireless communication step.

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