JP2018056932A - 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 communicable radio channel in high quality.SOLUTION: A radio base station device includes: a radio communication unit which performs radio communication with a communication terminal through one channel, using a first interface which is one of two radio interfaces; a state acquisition unit which, during the radio communication by the radio communication unit, acquires a radio wave state in the periphery of the radio base station device, using a second interface which is the other of the two radio interfaces, to store the acquired radio wave state into a storage unit; and a determination unit which, based on the communication state acquired by the radio communication unit and the radio wave state stored in the storage unit, determines a suitable channel which is estimated that radio communication can be performed with higher quality than the radio communication using the one channel. The radio base station device further includes a control unit which, when controlling the radio communication unit to perform radio communication using the second interface, controls the state acquisition unit to acquire the radio wave state using the first interface to store into the storage unit.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 uses a storage unit, two radio interfaces, and a first interface that is one of two radio interfaces to provide a communication terminal. Wireless communication using one channel and a wireless communication unit that acquires the communication status of one channel, and wireless communication using the second interface that is the other of the two wireless interfaces during wireless communication by the wireless communication unit. Based on the status acquisition unit that acquires the radio wave conditions around the base station device and stores the acquired radio wave status in the storage unit, the communication status acquired by the wireless communication unit, and the radio wave status stored in the storage unit A determination unit that determines a suitable channel estimated to be capable of wireless communication with higher quality than wireless communication using one channel, and the wireless communication unit uses a second interface In addition to controlling to perform wireless communication with the communication terminal using a suitable channel, and when controlling the wireless communication unit to perform wireless communication using the second interface, the situation acquisition unit further uses the first interface. And a control unit that controls to acquire the radio wave status and store the acquired radio wave status in the storage unit, and when the determination unit determines a preferable channel, wireless communication on the preferable channel by the second interface Then, the control unit starts wireless communication on the preferred channel by the second interface at the start time.

  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, and is suitable for a time zone in which radio communication with a communication terminal is less according to the purpose of use of radio communication. Channel switching to channel can be performed. As a result, it is possible to suppress the influence of wireless communication interruption time associated with channel switching.

  In addition, when the wireless communication unit is controlled to perform wireless communication using the second interface, the wireless communication management information (excluding the used channel) related to one channel used by the first interface for wireless communication is the second interface. Is duplicated and set.

  According to this, since the radio base station apparatus uses exactly the same parameters for communication in the two interfaces except for the communication channel, the radio communication disconnection time with the radio terminal can be minimized.

  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 wireless communication using the preferred channel. The notification signal is unicast transmitted to the communication terminal that is performing wireless communication.

  According to this, the radio base station apparatus can reliably notify the radio terminal side of the channel change.

  In addition, when acquiring the radio wave status, the status acquisition unit acquires the radio wave status multiple times over time in each channel that the radio base station device can use for radio communication while changing the channel. Is a channel in which the wireless communication bandwidth occupancy obtained from the radio wave situation acquired multiple times stored in the storage unit is lower than the wireless communication bandwidth occupancy obtained from the communication situation for a predetermined time or more. To determine 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.

  Further, when acquiring the radio wave status, the status acquisition unit captures surrounding frames in each channel that the radio base station apparatus can use for radio communication while changing the channel, and the determination unit stores the channel in the storage unit. A channel with a low congestion degree is determined as a preferred channel based on the state of wireless communication obtained from the stored frame capture logs acquired a plurality of times.

  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. Determining a candidate channel that is estimated to be capable of high-quality wireless communication; and (b) if the candidate channel is included in a frequency band in which a radar wave can exist, the presence or absence of a radar wave in the candidate channel is determined. The situation acquisition unit is monitored, and (c) when a 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, In the determination step of determining a suitable channel estimated to be capable of performing wireless communication with higher quality than wireless communication using a channel, and when performing wireless communication on a suitable channel using the second interface, (1) preferred channel Prior to the start of wireless communication by, a notification signal for notifying that the channel of wireless communication is switched to the preferred channel is unicast transmitted to the communication terminal performing wireless communication, and (2) the first interface is wireless Setting wireless communication management information (excluding used channel information) for one channel used for communication to perform wireless communication using the second interface, and using the second interface in the wireless communication step And a control step of controlling to perform wireless communication with the communication terminal on the suitable channel.

  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, the determined channel is wireless communication between the wireless base station device and the communication terminal from any timing. Used for. 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, or to prevent communication interruption at all. .

  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.

  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) and BSSID (Basic Service Set Identifier) are 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 and BSSID as the wireless interface W1 are 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 determination 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 and received (at least one of transmission and reception) by the communication interface 112, and the like.

  Also, 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 of the wireless interfaces W1 and W2 (the channel is This is realized when the communication terminal 20 performs connection switching. As will be described later, if the wireless communication management information for both wireless interfaces is the same except for the channel, the communication terminal recognizes that only the channel is changed. 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.

  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. The notification signal includes, for example, CSA in an action frame which is a frame format including a CSA (Channel Switch Announcement) defined by the IEEE 802.11h standard and a spectrum management action defined by the IEEE 802.11 standard (hereinafter referred to as an action frame). Also called CSA). In particular, it is preferable that the base station 10 notifies the change destination channel by unicast communication with the communication terminal 20 by using the Action Frame CSA. In this way, the channel to be changed can be reliably notified to the communication terminal 2 as compared to CSA (CSA defined by the IEEE 802.11h standard) that is included in the beacon and transmitted.

  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 communication interface 112 stores management information (hereinafter also referred to as wireless communication management information) necessary for wireless connection of a plurality of communication terminals connected to the base station 10. Here, the management information necessary for wireless connection includes management information of each communication terminal regarding authentication and encryption, management information required between the base station 10 and the driver of each communication terminal, and the like. Based on the wireless communication management information, the base station 10 and the communication terminal 20 perform wireless communication between each other. The communication interface 112 is realized by one of the wireless interfaces W1 and W2 and a part of the storage 104.

  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 occupancy rate for each channel, a frame capture log, a noise floor value of external noise, or detection of communication that may hinder its own communication. Here, the communication that can hinder its own communication is, for example, communication that bundles a plurality of channels such as noise that causes delay and IEEE802.11ac. Such communication is detrimental when it is desired to operate the wireless communication system 1 under an application that is required to suppress delay as much as possible. As the monitoring interface 114, one of the wireless interfaces W1 and W2 is dynamically used. Note that at which timing the status acquisition unit 113 uses the wireless interface W1 or W2 as the monitoring interface 114 is determined by the determination unit 116, and the specific timing is arbitrary. For example, it may be switched immediately when a better communication channel is found, or may be switched when the communication status in the current communication channel falls below a certain threshold. Alternatively, it is conceivable to reserve a switching time in a time zone when communication with each terminal is interrupted, such as at night. This is because it is possible to suppress the influence of wireless communication interruption time associated with channel switching. 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. The preferred channel, which is the channel estimated as 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 is a bandwidth occupancy rate or a radio frame capture log (hereinafter, “ Is also acquired by reading from the storage unit 115. Then, based on the communication status and the radio wave status, a suitable channel, which is a channel estimated to be capable of higher quality wireless communication, is determined. A specific determination method will be described in detail later.

  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. Further, the control unit 117 determines the preferred channel by the determination unit 116 and, when the channel switching time has arrived, the wireless communication management information (obtained through the communication interface 112) stored in the communication interface 112. The monitoring interface 114 is copied and stored, the function as the monitoring interface is stopped, and the preparation for starting the operation as the communication interface is started.

  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.

  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 having the number of terminals 601, the number of base stations 602, the number of communication frames 603, or the communication data amount 604 equal to or less than a predetermined value as a channel with low congestion. And the determination part 116 determines the channel obtained as a result of determination as a suitable channel. When determining a suitable channel, the degree of congestion may be comprehensively evaluated from the number of terminals 601, the number of base stations 602, the number of communication frames 603, and the amount of communication data 604. Any one or more analysis results obtained 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, and determines whether or not to switch to the preferable channel and the timing of switching. decide.

  In step S104, when the channel switching timing comes, the control unit 117 copies and stores the wireless communication management information in use (stored) in the communication interface 112 in the monitoring interface 114 prior to the switching. As described above, the channel switching timing is arbitrary.

  In step S105, the control unit 117 controls the wireless interface W2 used as the monitoring interface 114 so that the wireless communication unit 111 can be used as the new communication interface 112. Specifically, the wireless interface W2 is reset as a communication interface, the preferred channel determined in step S103 is set, and the wireless communication management information of the communication interface 112 stored in the monitoring interface 114 in step S104. Set.

  In step S106, the wireless communication unit 111 unicasts an action frame CSA including the preferred channel as a notification signal for channel switching from the communication channel to the preferred channel to the communication terminal 20.

  In step S107, the communication terminal 20 switches the connection of the communication link from the wireless interface W1 to the wireless interface W2. The connection switching is performed by the communication terminal 20 without disconnecting the communication link with the wireless interface W1 based on the information on the preferred channel by the action frame CSA in step S106 and the wireless communication management information stored in the wireless interface W2. This is done by establishing a communication link. That is, the wireless communication management information of the communication terminal 20 necessary for wireless connection can be referred to, and the communication link before connection switching can be taken over simply by changing the channel. Usually, in connection switching, a communication link is once disconnected and a new communication link needs to be established. In addition, according to a normal handover technique (conventional handover technique that is not a high-speed handover technique), a time for scanning a channel for searching for a connection destination base station (about several seconds, more specifically, 1-3 seconds) About 200 msec for authentication and the like necessary for connection of the communication link with the wireless interface W2.

  In step S108, after confirming that all connected communication terminals have been switched to a new communication channel, the wireless interface W2 notifies the wireless interface W1 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. That is, between steps S104 to S109, the two modules coexist on different channels and operate as communication interfaces.

  Through the series of processes described above, the base station 10 dynamically determines a channel capable of wireless communication with high quality, and the base station 10 and the communication terminal 20 perform wireless communication without disconnecting the communication link in the determined channel. It can be performed.

  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.

  Thereafter, as a result of monitoring the status of each channel using the monitoring interface as a monitoring interface, when a suitable channel is determined (step 103) and the timing for performing the process of switching to the preferred channel (step S104) comes, the control unit 117 An Action Frame CSA including a preferred channel is transmitted to the communication terminal 20 (step S106). When receiving this, the communication terminal 20 changes the channel (step S107).

  When the use of the wireless interface W2 is started as the communication interface 112, the communication terminal 20 switches the use channel to a suitable channel included in the ActionFrameCSA.

  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 made as short as possible or zero. 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 freely determine a convenient timing such as a time zone in which radio communication with the communication terminal is small according to the purpose of use of radio communication, and can perform channel switching to a suitable channel. As a result, it is possible to suppress the influence of wireless communication interruption time associated with channel switching.

  Further, the radio base station apparatus can give the communication terminal an opportunity to switch the channel by unicast wireless communication (ActionFrameCSA), and the communication terminal can surely receive the notification signal. It can be carried out.

  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, IEEE 802.11a (which is a frequency band in which radio waves used by weather radar or the like (hereinafter also referred to as “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 radar wave may exist, when the radio interface W1A starts using the channel, the radio interface W1A receives radio waves for 1 minute on the channel, and the radar wave It is stipulated that confirmation is made that no detection is made. The wireless interface W1A can perform wireless communication on the channel only when a radar wave is not detected on the channel for one minute. This is determined in order to avoid interference with the radar wave.

  Note that a conventional base station having only one radio interface has a radio communication for at least one minute (if a radar wave is detected during this one minute, another one minute for reception on another channel). This is a problem in operation. 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 to be described later, the situation acquisition unit 113A monitors the radar wave in the candidate channel and notifies the determination unit 116A whether or not a 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 radar wave is monitored in the candidate channel using the situation acquisition unit 113A and the monitoring interface 114. When a radar wave is not detected in the candidate channel, the candidate channel is determined as a preferred channel. When a radar wave is detected in the candidate channel, the determination unit 116A determines another candidate channel and monitors the radar wave in the candidate channel until it finds a candidate channel in which no radar wave is detected. repeat.

  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 radar wave is detected in step S203, which will be described later, candidate channels are determined by excluding channels in which radar waves are detected.

  In step S202, the determination unit 116A uses the situation acquisition unit 113A and the monitoring interface 114 to monitor the radar wave in the candidate channel.

  In step S <b> 203, the status acquisition unit 113 </ b> A determines whether or not a radar wave is detected by the monitoring interface 114. If a radar wave is detected (Yes in step S203), step S201 is performed again. If the radar wave is not detected (No in step S203), the process proceeds to step S204.

  In step S204, the determination unit 116A immediately determines a candidate channel for which no radar wave has been detected in step S203 as a suitable 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 radar wave, and after confirming that no radar wave is detected, the channel can be switched. it can. 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 radar waves when the radio interface W1 as the communication interface 112 is performing radio communication. Therefore, 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 radar wave. The channel can be determined appropriately.

  As described above, the radio base station apparatus according to the present embodiment appropriately uses the two radio interfaces to select a suitable channel when using a channel included in a frequency band in which radar waves can exist as a suitable channel. It is possible to shorten the wireless communication interruption time associated with the channel switching 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

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. The notification signal includes, for example, CSA in an action frame, which is a frame format including a CSA (Channel Switch Announcement) defined by the IEEE 802.11h standard and a spectrum management action defined by the IEEE 802.11 standard (hereinafter referred to as an action frame). CSA also hump) can be. In particular, it is preferable that the base station 10 notifies the change destination channel by unicast communication with the communication terminal 20 by using the Action Frame CSA. In this way, the channel to be changed can be reliably notified to the communication terminal 2 as compared to CSA (CSA defined by the IEEE 802.11h standard) that is included in the beacon and transmitted. However, a plurality of display devices may be connected to one relay device, and a plurality of client devices may use different display devices by switching.

Claims (8)

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;
The wireless communication unit is controlled to perform wireless communication with the communication terminal on the preferred channel using the second interface, and the wireless communication unit is controlled to perform wireless communication using the second interface. In this case, the status acquisition unit further includes a control unit that acquires the radio wave status using the first interface and controls the acquired radio wave status 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 said control part is a radio base station apparatus which starts the radio | wireless communication in the said suitable channel by said 2nd interface at the said start time.
When the wireless communication unit is controlled to perform wireless communication using the second interface, wireless communication management information (excluding used channels) related to the one channel is copied and set to the second interface. The radio base station apparatus according to claim 1.
The wireless communication unit
When performing wireless communication on the preferred channel using the second interface, a notification signal for notifying that the wireless communication channel is to be switched to the preferred channel prior to the start of wireless communication using the preferred channel is provided. The radio base station apparatus according to claim 1, wherein the radio base station apparatus is unicast transmitted to a communication terminal performing radio communication.
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 situation acquisition unit captures surrounding wireless communication frames in each channel that the wireless base station apparatus can use for wireless communication while changing the channel when acquiring the radio wave condition,
2. The determination unit determines a channel with a low congestion degree as the preferred channel based on a wireless communication situation obtained from the wireless frame capture log acquired a plurality of times stored in the storage unit. The radio base station apparatus according to any one of?
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 radar wave can exist, the situation acquisition unit monitors the presence / absence of a radar wave in the candidate channel, The radio base station apparatus according to claim 1, wherein the candidate channel is determined as a suitable channel when a radar wave is not detected in the candidate channel.
The radio base station apparatus according to any one of claims 1 to 6,
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;
When performing wireless communication on the preferred channel using the second interface, (1) for informing that the wireless communication channel is switched to the preferred channel prior to the start of wireless communication using the preferred channel. A notification signal is unicast transmitted to a communication terminal that is performing wireless communication, and (2) wireless communication management information (excluding used channel information) related to the one channel used by the first interface for wireless communication, Setting to perform wireless communication using the second interface;
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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