JP5159714B2 - Control device, control method and program - Google Patents

Control device, control method and program Download PDF

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JP5159714B2
JP5159714B2 JP2009155777A JP2009155777A JP5159714B2 JP 5159714 B2 JP5159714 B2 JP 5159714B2 JP 2009155777 A JP2009155777 A JP 2009155777A JP 2009155777 A JP2009155777 A JP 2009155777A JP 5159714 B2 JP5159714 B2 JP 5159714B2
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radio
communication
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JP2011015048A (en
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裕介 淺井
泰司 鷹取
健太郎 西森
匡人 溝口
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日本電信電話株式会社
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  The present invention relates to a control device, a control method, and a program.
  In a wireless LAN system (for example, IEEE802.11a (developed in 1997, hereinafter abbreviated as “11a” or “11a mode”), IEEE802.11n (planned for September 2009)) In order to coexist with weather radars that are operating at some of the available frequencies, dynamic frequency selection (hereinafter abbreviated as “DFS”) is used when used outdoors. The specification is defined in IEEE 802.11h (prepared in 2003; hereinafter abbreviated as “11h”).
  11a stipulates that a 20 MHz radio channel (a radio channel having a basic unit of 20 MHz is also referred to as “basic channel” or “unit channel”) is used. That is, in 11a, one basic channel is used as a radio channel. When the radio channel is changed in DFS, the entire 20 MHz channel bandwidth is changed to a radio channel having a different center frequency.
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In addition to the communication mode that uses a 20 MHz channel bandwidth (one basic channel), IEEE 802.11n, which is a higher standard of 11a, in addition to a communication mode that uses a 20 MHz channel bandwidth (one basic channel), There are communication modes in which high-speed transmission is performed using two basic channels). Hereinafter, a communication mode using one basic channel is abbreviated as “11n (20 MHz) mode” or simply “20 MHz mode”, and a communication mode using two basic channels is “11n (40 MHz) mode” or simply “40 MHz”. Abbreviated as “mode”.
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IEEE802.11n supports both 20 MHz mode transmission and 40 MHz mode transmission simultaneously and with one physical medium and medium access medium so that the wireless device has a simple configuration while having backward compatibility. The design is such that control signals are transmitted using only the 20 MHz channel, which is the upper half of the 40 MHz band, or the 20 MHz channel, which is the lower half. The 20 MHz channel for transmitting the control signal is called a primary channel, and the other 20 MHz channel not corresponding to the primary channel is called a secondary channel. The terminal in the 11a mode and the terminal in the 11n (20 MHz) mode perform transmission using only the primary channel like the control signal. The secondary channel is used only for transmission using the entire 40 MHz band.
  In addition, IEEE802.11ac (hereinafter abbreviated as “11ac” or “11ac mode”), which is being newly standardized in recent years, is expected to define a communication mode that simultaneously bundles up to 4 channels of 20 MHz bandwidth. Yes (see Non-Patent Document 1). Further, the 11ac mode is required to have backward compatibility with the 11a mode, the 11n (20 MHz) mode, and the 11n (40 MHz) mode.
  FIG. 10 shows a case where there are a mixture of terminals in three types of communication modes, an 11a mode terminal, an 11n (20 MHz) mode terminal, and an 11n (40 MHz) mode terminal with respect to an access point using a 40 MHz band. This is an example of a radio channel used by each terminal. In FIG. 10, the 20 MHz band with the lower frequency is the primary channel.
  FIG. 11 is an example of radio frame transmission (an example of switching between the 20 MHz mode and the 40 MHz mode) at an access point corresponding to the 11n (20 MHz) mode and the 11n (40 MHz) mode. As conceptually shown in FIG. 11, the secondary channel is used only for transmission in the 11n (40 MHz) mode, and the primary channel is used for transmission in all communication modes.
  In IEEE 802.11 wireless LAN, primary channel and secondary channel information (center frequency) is stored in a beacon frame that broadcasts system operation information to all terminals under the access point, and is based on a predetermined period. Send regularly. In IEEE 802.11n, a beacon frame is transmitted using the primary channel when operating in 40 MHz mode. Other access points and terminals located in the vicinity detect the presence of the access point and the channel to be used by reading the beacon frame.
  The access point notifies the center frequency of the primary channel and the secondary channel periodically to all the terminals under its control using a beacon frame, while if it detects an interference wave such as weather radar during operation, It is necessary to change the radio channel to be used. The access point can also change the radio channel even when the radio channel being used is congested. The transition procedure is specified in the 11h standard. In other words, the access point notifies the center frequency and transition timing of the transition destination wireless channel using a control frame, and the access point and all the terminals under the access point simultaneously transition the wireless channel in synchronization with the timing when the timer becomes 0. .
  11h, in IEEE 802.11n, when the access point is powered on, the frequency to be operated is measured after measuring the channel state for the frequency band that is a candidate for use in order to determine the frequency band to be used (used) by itself. Determine the channel. There are 22 frequency channels (basic channels) of 20 MHz width that can be operated by the current 5 GHz wireless IEEE 802.11n.
Eldad Perahia, "VHT below 6 GHz PAR Plus 5C's," 17, Sep, 2008, [online], [Search June 10, 2009], Internet <URL: https://mentor.ieee.org/802.11/ dcn / 08 / 11-08-0807-04-0vht-below-6-ghz-par-nescom-form-plus-5cs.doc>
  However, when the 11n (40 MHz) mode using two radio channels and the 11ac mode using four radio channels are operated, there is a high possibility that radio channels used between adjacent access points overlap (compete). Therefore, there is a problem that transmission throughput is likely to be reduced by communication control of CSMA (Carrier Sense Multiple Access). That is, as in the case where the number of access points with overlapping radio channels is increased, even when the number of radio channels used for each communication is increased, simultaneous operation is possible by control by CSMA (Carrier Sense Multiple Access). As the transmission opportunity decreases, the throughput tends to decrease. For example, in an apartment house, when an access point supporting 11n (40 MHz) mode or 11ac mode is installed for each house, there is a possibility that radio channels (frequency bands) overlap frequently. Therefore, it is necessary to control the radio channel so that the frequency bands used by the access points do not overlap as much as possible.
  The present invention has been made in consideration of such circumstances, and an object of the present invention is to provide a simple technique for suppressing a decrease in throughput due to radio channel contention between a plurality of access points. .
In order to solve the above-described problem, a control device according to an embodiment of the present invention is a control device that controls a wireless communication system, and observes the usage status of wireless channels in a predetermined wireless channel group by other systems. A channel observation unit, a channel information transmission / reception unit that receives channel information indicating the usage status of the radio channel by another control device constituting the radio communication system, the usage status and the channel observed by the channel observation unit A channel selection unit that selects a radio channel to be used for communication with each terminal from the radio channel group based on the channel information received by the information transmission / reception unit, and the channel selection unit is used by the other system And one or more radio channels that are less used by the other control device Select from Yaneru group, wherein the wireless communication system, a radio channel used by the terminal accommodated to the plurality of control devices and the control devices constituting the radio communication system defines a plurality of basic channels, the control As a communication mode between a device and the terminal, there are a plurality of communication modes with different numbers of basic channels used for communication, and overlap in a plurality of communication modes between each control device and each terminal accommodated in each control device. The channel information received by the channel information transmitting / receiving unit includes a communication mode used by the other control device and a basic channel used in each communication mode. The channel selection unit includes the number of other devices that are used by the other control device. It is calculated for each basic channel, and the maximum of the total number of used for each basic channel obtained by adding the number of used for each basic channel used in the control device to the number of used for other devices for each basic channel The radio channel used for communication with each terminal is selected so that the total number of uses in the one basic channel is minimized .
  In the control device, the channel selection unit is the basic channel that is used redundantly, and the channel information transmitting / receiving unit receives the channel information. As for the basic channel other than the basic channel that is determined as the basic channel and transmits / receives the channel information, the total number of use in one basic channel that is the maximum among the total number of use for each basic channel is minimized. In addition, a radio channel used for communication with each terminal may be selected.
  In the control device, the channel information received by the channel information transmitting / receiving unit further includes information indicating the number of terminals using each communication mode used by the other control device, and the channel selection unit includes: The number of other devices used may be calculated for each basic channel by multiplying the number of terminals.
  In the control apparatus, the channel information transmitting / receiving unit may transmit information indicating a radio channel selected by the channel selecting unit as the channel information.
  In the control device, the channel information transmission / reception unit includes, as the channel information, information indicating the use status of the radio channel by the other system observed by the other control device in addition to the use status by the other control device. Information indicating the usage status received by the channel observation unit may be transmitted.
In order to solve the above-described problem, a control method according to another embodiment of the present invention is a control method for controlling a wireless communication system, and the usage status of a wireless channel in a predetermined wireless channel group by another system is controlled. Radio channel observation means for observing, channel information transmitting / receiving means for receiving channel information indicating the usage status of the radio channel by other control devices constituting the radio communication system, and the usage status observed by the radio channel observation means And channel selection means for selecting a radio channel to be used for communication with each terminal from the radio channel group based on the channel information received by the channel information transmission / reception means, and the channel selection means One or more which is not used by the system and is less used by the other control device Select the line channel from the radio channel group, wherein the wireless communication system, a radio channel used by the terminal accommodated to the plurality of control units and the control units constituting the wireless communication system, a plurality of basic channels As a communication mode between the control device and the terminal, a plurality of communication modes having different basic channel numbers used for communication are provided, and a plurality of communication modes between each control device and each terminal accommodated in each control device are provided. The channel information received by the channel information transmitting / receiving means is used in the communication mode used by the other control device and in each communication mode. Information indicating a basic channel to be transmitted, and the channel selection means includes the basic channel by the other control device. The basic channel obtained by calculating the number of other devices used as the number of used for each basic channel, and adding the number of used for each basic channel used in the control device to the number of other devices used for each basic channel A radio channel to be used for communication with each terminal is selected so that the total number of use in one of the basic channels, which is the largest among the total number of use for each, is minimized .
  In the control method, the channel selection unit is the basic channel that is used redundantly, and the channel information transmission / reception unit receives the channel information. As for the basic channel other than the basic channel that is determined as the basic channel and transmits / receives the channel information, the total number of use in one basic channel that is the maximum among the total number of use for each basic channel is minimized. In addition, a radio channel used for communication with each terminal may be selected.
  In the control method, the channel information received by the channel information transmitting / receiving unit further includes information indicating the number of terminals using each communication mode used by the other control device, and the channel selection unit includes: The number of other devices used may be calculated for each basic channel by multiplying the number of terminals.
  In the control method, the channel information transmitting / receiving unit may transmit information indicating a radio channel selected by the channel selecting unit as the channel information.
  In the control method, the channel information transmission / reception means includes, as the channel information, information indicating the usage status of the radio channel by the other system observed by the other control device in addition to the usage status by the other control device. Information indicating the usage status received by the wireless channel observation means may be transmitted.
In order to solve the above-described problem, a program according to another embodiment of the present invention includes a radio channel observation step of observing a use status of a radio channel in a predetermined radio channel group by another system, and the radio communication system. A channel information transmission / reception step for receiving channel information indicating the usage status of the radio channel by the other control device to be configured; the usage status observed in the radio channel observation step; and the channel information received in the channel information transmission / reception step. And a channel selection step of selecting a radio channel to be used for communication with each terminal from the radio channel group, wherein the channel selection step is not used by the other system, and Less used by the other control device 1 Select the radio channel of the upper from the radio channel group, wherein the wireless communication system, a radio channel used by the terminal accommodated to the plurality of control units and the control units constituting the wireless communication system, a plurality of base A channel is defined, and a communication mode between the control device and the terminal has a plurality of communication modes in which the number of basic channels used for communication is different, and between each control device and each terminal accommodated in each control device The channel information received by the channel information transmitting / receiving means includes a communication mode used by the other control device and each communication mode. Information indicating a basic channel used in the channel selection step, and the channel selection step includes: The number of other devices used which is the number of used channels is calculated for each basic channel, and the number of other devices used for each basic channel is added to the number of used for each basic channel used in the control device. The wireless channel used for communication with each terminal is selected so that the total number of use in one basic channel that is the maximum among the total number of use for each basic channel is minimized .
  According to the present invention, it is possible to minimize a decrease in throughput due to radio channel contention between a plurality of access points.
It is a structural example of the radio | wireless communications system 1 containing the control apparatus 10 by one Embodiment of this invention. It is a schematic diagram which shows the use condition of each channel. It is a schematic diagram which shows the use condition of the channel acquired from a control frame. It is a schematic diagram which shows the number of duplication communication modes of each channel. It is a schematic diagram which shows the arrangement pattern of a channel. It is a schematic diagram which shows the example of a combination with which the maximum value of a total usage number becomes the minimum, and the example of a combination with which the maximum value of a total usage number does not become the minimum. It is a schematic diagram which shows the use condition of the channel acquired from a control frame. It is a schematic diagram which shows the number of duplication communication modes of each channel. 4 is a flowchart showing an example of the operation of the control device 10. It is a conceptual diagram of a primary channel and a secondary channel. It is the example of transmission of the radio | wireless frame in the access point corresponding to 11n (20 MHz) mode and 11n (40 MHz) mode.
  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a configuration example of a wireless communication system 1 including a control device 10 according to an embodiment of the present invention. The wireless communication system 1 corresponds to a plurality of control devices (control devices 10, 30, and 40 in the example of FIG. 1) and a terminal station (a terminal of the present invention) accommodated in each control device. Terminal stations 20-1, ..., 20-4). The radio communication system 1 defines a plurality of basic channels (20 Mhz) as radio channels used by a plurality of control devices and each terminal station. The wireless communication system 1 also supports a plurality of communication modes with different numbers of basic channels used for communication as communication modes between the control device and the terminal station. Further, in the wireless communication system 1, there are one or more basic channels that are used redundantly in a plurality of communication modes.
  The control devices 10, 30, and 40 are devices that control the wireless communication system 1, and are devices that serve as access points in a wireless LAN, for example. As shown in FIG. 1, the control device 10 includes a channel observation unit 100, a channel information transmission / reception unit 110, and a channel selection unit 120.
  The channel observation unit 100 observes the usage status of other radio channels (a plurality of basic channels defined in the radio communication system 1) in a predetermined radio channel group by other systems. When observing the usage status, the channel observation unit 100 supplies the channel selection unit 120 with information indicating the observed usage status (hereinafter referred to as “observation information”). An example of another system is a weather radar system.
  The channel information transmitting / receiving unit 110 receives channel information indicating the usage status of the radio channel by the other control devices 30 and 40 from each control device 30 and 40. The channel information received by the channel information transmitting / receiving unit 110 from the other control device 30 (the same applies to the channel information received from the other control device 40) is used in the communication mode used by the other control device 30 and in each communication mode. This information includes information indicating the basic channel to be played. Further, the channel information received by the channel information transmitting / receiving unit 110 from the other control device 30 (the same applies to the channel information received from the other control device 40) uses each communication mode used by the other control device 30. The information may further include information indicating the number of terminal stations that are present. That is, the information may further include information indicating the number of terminal stations accommodated in another control device 30 for each communication mode.
  Note that the channel information is transmitted and received using one basic channel that is stored in a control frame and used redundantly in a plurality of communication modes. When channel information is received, the channel information transmission / reception unit 110 supplies the received channel information to the channel selection unit 120.
  Further, the channel information transmission / reception unit 110 transmits information indicating the radio channel selected by the channel selection unit 120 to the terminal stations 20-1, ..., 20-4 as channel information. Note that the channel information transmission / reception unit 110 may transmit information indicating the radio channel selected by the channel selection unit 120 to other control devices 30 and 40 as channel information.
  Further, the channel information transmission / reception unit 110 displays observation information indicating the use status of the radio channel by another system observed by the other control devices 30 and 40 in addition to the use status of the radio channel by the other control devices 30 and 40. It may be received as information. Further, the channel information transmission / reception unit 110 may transmit observation information indicating the usage state observed by the channel observation unit 100 to the other control devices 30 and 40.
  The channel selection unit 120 acquires observation information from the channel observation unit 100. Further, the channel selection unit 120 acquires channel information from the channel information transmission / reception unit 110. When the channel selection unit 120 acquires the observation information and the channel information, the usage status of each radio channel by the other system indicated by the observation information, and each radio channel by the other control devices 30 and 40 indicated by the channel information Based on the usage status, a radio channel to be used for communication with each of the terminal stations 20-1,. Specifically, the channel selection unit 120 selects one or more radio channels that are not used by other systems and are less used by the other control devices 30 and 40 from the radio channel group.
  More specifically, the channel selection unit 120 first calculates the number of basic channels used by the other control devices 30 and 40 (hereinafter referred to as “the number of other devices used”) for each basic channel. In addition, when the channel selection unit 120 acquires channel information including terminal number information indicating the number of terminal stations using each communication mode used by the other control devices 30 and 40, the channel selection unit 120 is indicated by the terminal number information. The number of other devices used may be calculated for each basic channel by multiplying the number of terminals.
  The channel selection unit 120 that calculates the number of other devices used for each basic channel uses the number of other devices used for each basic channel as the number of used devices for each basic channel used in the control device 10 (hereinafter referred to as “the number of own devices used”). Are used for communication with each of the terminal stations 20-1,... 20-4 so that the total number of use in one basic channel that is the maximum among the total number of use for each basic channel obtained by adding A channel is selected from a group of radio channels.
  Note that the channel selection unit 120 uses a basic channel (control frame) that is used in duplicate in a plurality of communication modes and is used for transmission / reception of channel information. Basic channels that are also used for transmission of each of the basic channels, and for each of the basic channels other than the basic channel, the total used number of one basic channel that is the maximum among the total used number of each basic channel is minimized. The radio channel used for communication with the terminal stations 20-1,... 20-4 may be selected from the radio channel group.
  When the channel selection unit 120 selects a radio channel to be used for communication with each of the terminal stations 20-1 to 20-4, the channel selection unit 120 supplies information indicating the selected radio channel to the channel information transmission / reception unit 110.
  The channel selection unit 120 supplies the channel information transmission / reception unit 110 with information indicating the number of terminal stations 20-1 to 20-4 accommodated in the communication mode, together with information indicating the selected radio channel. May be. Further, the channel selection unit 120 supplies the observation information acquired from the channel observation unit 100 to the channel information transmission / reception unit 110 when the channel information transmission / reception unit 110 transmits the observation information to the other control devices 30 and 40.
Hereinafter, a specific example will be described. The control device 10 conforms to the IEEE 802.11 system and corresponds to the following four types of communication modes.
1.11a mode: 20 MHz
2.11n (20MHz) mode: 20MHz
3.11n (40MHz) mode: 40MHz
4.11ac mode ... 80MHz
As shown in FIG. 1, the control apparatus 10 accommodates terminal stations 20-1,..., 20-4, and each terminal station uses the following communication mode.
Terminal station 20-1: 11a mode terminal station 20-2: 11n (20 MHz) mode terminal station 20-3: 11n (40 MHz) mode terminal station 20-4: 11ac mode
  It is assumed that other control devices 30 and 40 exist in the vicinity of the control device 10 as shown in FIG. It is assumed that there are a total of 11 basic channels (radio channels in a predetermined radio channel group) that are candidates for use, that is, ch # 01 to ch # 11. Hereinafter, unless otherwise specified, the basic channels ch # 01 to ch # 11 are simply referred to as channels.
Now, as shown in FIG. 2, the other control devices 30 use ch # 01 to ch # 04, the other control devices 40 use ch # 05 to ch # 08, and ch # 09 to ch # 11. It is assumed that there is an interference wave from a weather radar related to another system. For convenience of explanation, it is assumed that the communication mode and channel have the following conditions (restrictions).
Condition 1: 11n (40 MHz) mode uses two consecutive channels.
Condition 2: 11ac mode uses four consecutive channels.
Condition 3: 11a (20 MHz) and 11n (20 MHz) modes use the same channel.
Condition 4: One of the two channels used by the 11n (40 MHz) mode is the same as the one channel used by the 11a (20 MHz) mode and the 11n (20 MHz) mode.
Condition 5: Two of the four channels used by the 11ac mode are the same as the two channels used by the 11n (40 MHz) mode.
  As described above, the above conditions are set for convenience of explanation. The present invention can also be applied to a wireless communication system that does not have this condition. For example, even if the 11n (40 MHz) mode and the 11ac mode use a plurality of discontinuous channels or use completely different channels in each communication mode, the same effect can be obtained.
  The control device 10 is excited, and first, the channel information receiving unit 100 observes the usage status of surrounding channels. Thereby, the interference wave of the weather radar is observed at ch # 09 to ch # 11. That is, the control device 10 detects that ch # 09 to ch # 11 cannot be used.
  The other control devices 30 and 40 transmit information (channel information) about the channel used by each using the control frame. The control device 10 receives and decodes the control frame transmitted by the other control devices 30 and 40 by the channel information transmission / reception unit 110, and acquires the channel usage status. FIG. 3 is an example of a channel usage status acquired from control frames transmitted by other control apparatuses 30 and 40. According to FIG. 3, for example, ch # 01 is used for 11n (40 MHz) mode and 11ac mode, and ch # 02 is used for 11a mode, 11n (20 MHz) mode, 11n (40 MHz) mode, and 11ac mode. Yes. Note that the channel information transmitted by the other control devices 30 and 40 includes difference information, for example, the IEEE 802.11n primary channel (channel number itself), the location of the 11n secondary channel (upper side of the primary channel). Or the lower side).
  The interference state obtained by the above procedure (the presence of an interference wave by the weather radar) and the channel usage status by the other control devices 30 and 40 are input to the channel selection unit 120. The channel selection unit 120 refers to a channel used by each terminal station, and uses a channel used by a terminal station under its control (control device 10) and a channel used by other control devices 30 and 40. The channel arrangement with the smallest overlap is derived (the channel assigned to the terminal station is selected).
The specific procedure is as follows. First, the control device 10 uses the channel selection unit 120 to count the number of overlapping communication modes (number of other devices used) for each channel. Note that the channel usage is based on the example of FIG.
ch # 01: 11n (40 MHz) mode, 11ac mode → duplicate communication mode number = 2
ch # 02: 11a mode, 11n (20 MHz) mode, 11n (40 MHz) mode, 11ac mode → number of overlapping communication modes = 4
ch # 03: 11ac mode → number of duplicate communication modes = 1
ch # 04: 11ac mode → number of duplicate communication modes = 1
ch # 05: 11ac mode → number of duplicate communication modes = 1
ch # 06: 11n (40 MHz) mode, 11ac mode → number of duplicate communication modes = 2
ch # 07: 11a mode, 11n (20 MHz) mode, 11n (40 MHz) mode, 11ac mode → number of overlapping communication modes = 4
ch # 08: 11ac mode → number of duplicate communication modes = 1
ch # 09: Weather radar is present → (Not available)
ch # 10: Weather radar is present → (Not available)
ch # 11: Weather radar is present → (Not available)
  FIG. 4 is a schematic diagram showing the number of overlapping communication modes (number of other devices used) of each channel based on the counting result.
  Next, the control device 10 uses the channel selection unit 120 to add the number of used channels (the number of other devices used) in the control device 10 to the number of overlapping communication modes (number of other devices used) counted for each channel. Calculate the number of overlapping communication modes (total number of uses) for each channel, and use it for communication with each terminal station so that the total number of use in one channel, which is the maximum among the total number of uses for each channel, is minimized. Select the channel to be used. For example, the control device 10 calculates the total number of uses in each combination of channel arrangements that can be used in the control device 10, and selects a channel according to the channel arrangement of the combination that minimizes the maximum value of the total number of uses. This will be specifically described with reference to FIGS.
  FIG. 5 shows channel arrangement patterns for each communication mode that the control apparatus 10 can take. The arrangement patterns that the control device 10 can take are six types (pattern 1 to pattern 6) from a predetermined condition (condition 1 to condition 5). Further, n is a channel number, but considering the presence of weather radar, possible values of channel number n in each pattern are {1, 2, 3, 4, 5}. Therefore, the total number of combinations of channel arrangements that can be used is 30 (6 × 5).
The control device 10 calculates the total number of uses in each combination for all 30 sets, and selects a channel according to the channel arrangement of the combination that minimizes the maximum value of the total number of uses. In this example, the combination with the smallest total usage number is the following five groups (A group, B group, C group, D group, E group) with the maximum total usage number being 5. The control device 10 selects a channel according to any one of the following five channel arrangements.
(A set) n = 3, pattern 1
(Class B) n = 3, pattern 2
(C set) n = 3, pattern 3
(D set) n = 3, pattern 4
(E group) n = 3, pattern 5
  FIG. 6A shows a channel arrangement of a combination (A set) that minimizes the maximum total number of uses, and FIG. 6B shows a channel arrangement of a combination (B set) that minimizes the maximum total use number. FIG. 6C shows a channel arrangement of a combination (n = 1, pattern 2) where the maximum value of the total usage is not minimum, and FIG. 6D is a combination where the maximum value of the total usage is not minimum (n = 5). , Pattern 6). In FIG. 6, the inside of the thick frame is an additional portion by each combination of channel arrangements usable in the control apparatus 10.
  For example, the control apparatus 10 selects ch # 03 for the terminal station 20-1 in the 11a mode and selects ch # 03 for the terminal station 20-2 in the 11n (20 MHz) mode according to the channel arrangement of the A set. Then, ch # 03 and ch # 04 are selected for the terminal station 20-3 in the 11n (40 MHz) mode, and ch # 03, ch # 04, ch # 05, ch # are selected for the terminal station 20-4 in the 11ac mode. Select 06.
  Note that the above-described functions of the control device 10 are added at the time of excitation, and the channels included in the control frames received from other control devices 30 and 40 are observed during the period when communication with the terminal station has already been started. This may also be applied when a channel in use is transitioned with reference to information.
  Subsequently, a case where channel usage information including terminal number information indicating the number of terminal stations accommodated in the other control devices 30 and 40 by communication mode is received, and other channel selection criteria will be described.
It is assumed that the channel usage status by the other control devices 30 and 40 is as shown in FIG. The number of terminal stations in each communication mode in the other control devices 30 and 40 is as follows.
(Control device 30)
Number of terminal stations in 11a mode: Number of terminal stations in 1 station 11n (20 MHz) mode: Number of terminal stations in 1 station 11n (40 MHz) mode: Number of terminal stations in 1 station 11ac mode: 1 station (control device 40)
Number of terminal stations in 11a mode: Number of terminal stations in 4 stations 11n (20 MHz) mode: Number of terminal stations in 3 stations 11n (40 MHz) mode: Number of terminal stations in 2 stations 11ac mode: 3 stations
  FIG. 7 is an example of a channel usage status acquired from control frames transmitted by other control apparatuses 30 and 40.
When acquiring the channel information including the number-of-terminals information indicating the number of terminal stations, the control device 10 multiplies the number of terminals indicated by the number-of-terminals information to count the number of overlapping communication modes (number of other devices used).
ch # 01: 11n (40 MHz) mode × 1, 11ac mode × 1 → number of overlapping communication modes = 2
ch # 02: 11a mode × 1, 11n (20 MHz) mode × 1, 11n (40 MHz) mode × 1, 11ac mode × 1 → number of overlapping communication modes = 4
ch # 03: 11ac mode × 1 → number of overlapping communication modes = 1
ch # 04: 11ac mode × 1 → number of overlapping communication modes = 1
ch # 05: 11ac mode × 3 → number of duplicate communication modes = 3
ch # 06: 11n (40 MHz) mode × 2, 11ac mode × 3 → number of duplicate communication modes = 5
ch # 07: 11a mode × 4, 11n (20 MHz) mode × 3, 11n (40 MHz) mode × 2, 11ac mode × 3 → number of overlapping communication modes = 12
ch # 08: 11ac mode × 3 → number of duplicate communication modes = 3
ch # 09: Weather radar is present → (Not available)
ch # 10: Weather radar is present → (Not available)
ch # 11: Weather radar is present → (Not available)
  FIG. 8 is a schematic diagram showing the number of overlapping communication modes (number of other devices used) of each channel based on the counting result. According to FIG. 8, among the channels used by the control apparatus 10, the control frame is transmitted for the channels selected for the terminal stations in the 11a mode and the 11n (20 MHz) mode. Greatly affects. Therefore, the control device 10 selects a channel to be used for communication with each terminal station so that the characteristic deterioration is reduced as much as possible.
  First, the control device 10 causes the channel selection unit 120 to minimize the number of overlapping communication modes (the number of other devices used) for the terminal station 20-1 in the 11a mode and the terminal station 20-2 in the 11n (20 MHz) mode. Either channel # 03 or ch # 04 is selected. Specifically, when the control apparatus 10 selects ch # 03 for the terminal station 20-1 in the 11a mode according to the above condition 3, the control apparatus 10 also selects the terminal station 20-2 in the 11n (20 MHz) mode. When ch # 03 is selected and ch # 04 is selected for the terminal station 20-1 in the 11a mode, ch # 04 is also selected for the terminal station 20-2 in the 11n (20 MHz) mode.
  Subsequently, the control device 10 transfers the terminal station 20-3 in the 11n (40 MHz) mode to the terminal station 20-1 in the 11a mode and the terminal station 20-2 in the 11n (20 MHz) mode according to the above conditions 1 and 4. On the other hand, when selecting ch # 03, select one of {ch # 02, ch # 03} {ch # 03, ch # 04}, and select 11a terminal stations 20-1 and 11n (20 MHz) mode. When ch # 04 is selected for the terminal station 20-2, one of {ch # 03, ch # 04} {ch # 04, ch # 05} is selected.
  Subsequently, when the control apparatus 10 selects {ch # 02, ch # 03} for the terminal station in the 11n (40 MHz) mode according to the above conditions 2 and 5 for the terminal 20-4 in the 11ac mode, { ch # 01 to ch # 04} {ch # 02 to ch # 05} is selected, and {ch # 03, ch # 04} is selected for the terminal station in 11n (40 MHz) mode, { ch # 01 to ch # 04} {ch # 02 to ch # 05} {ch # 03 to ch # 06} are selected, and the terminal station in 11n (40 MHz) mode is set to {ch # 04, ch # 05} is selected, any one of {ch # 02 to ch # 05} {ch # 03 to ch # 06} {ch # 04 to ch # 07} is selected.
  When the control device 10 selects (assigns) a channel to each terminal station from the above combinations, the number of overlapping communication modes in one channel (total) among the maximum number of overlapping communication modes (total number of uses) for each channel. Select the channel so that the number of uses is minimized.
  The controller 10 first determines channel selection for the terminal station 20-1 in 11a mode and the terminal station 20-2 in 11n (20 MHz) mode, and then the terminal station 20-3 in 11n (40 MHz) mode. When the channel selection of the terminal station 20-4 in the 11n (40 MHz) mode is determined, the number of duplicate communication modes (total use) in one channel that is the maximum among the number of duplicate communication modes (total use number) for each channel The channel may be selected so that (number) is minimized. For example, when the control apparatus 10 selects ch # 03 for the terminal station 20-1 in the 11a mode and the terminal station 20-2 in the 11n (20 MHz) mode, the control apparatus 10 selects the terminal station 20-3 in the 11n (40 MHz) mode. {Ch # 02, ch # 03} {ch # 03, ch # 04} or {ch # 01 to ch # 04} {ch # 02 to ch for the terminal 20-4 in the 11ac mode # 05} Since the number of options decreases in any of {ch # 03 to ch # 06}, the processing is accelerated.
  Further, the control device 10 first determines channel selection for the terminal station 20-1 in the 11a mode and the terminal station 20-2 in the 11n (20 MHz) mode, and then, the terminal station 20- in the 11n (40 MHz) mode. 3 and the channel selection of the terminal station 20-4 in the 11n (40 MHz) mode is determined, the largest one of the number of overlapping communication modes (total number of use) for each channel is determined. The channel may be selected so that the number of overlapping communication modes (total number of uses) in the channel is minimized. For example, the control device 10 selects ch # 03 for the terminal station 20-1 in 11a mode and the terminal station 20-2 in 11n (20 MHz) mode, and { If ch # 03, ch # 04} is selected, only options {ch # 01 to ch # 04} {ch # 02 to ch # 05} {ch # 03 to ch # 06} for the terminal 20-4 in the 11ac mode Therefore, the processing is further accelerated.
  In addition, when the control apparatus 10 is already communicating with the terminal stations 20-1 to 20-4 under its control, it is possible to derive a channel arrangement using the information. However, when the control device 10 is excited and started, since the subordinate terminal stations 20-1 to 20-4 are not connected, the terminal number information in each mode is not acquired. Therefore, provisionally, a channel arrangement is set in which the number of overlapping communication modes in all modes is set to 1, and the maximum number of overlapping communication modes for each channel is minimized.
  Hereinafter, the operation of the control device 10 will be described with reference to FIG. The channel information transmitting / receiving unit 110 of the control device 10 receives channel information from each of the other control devices 30 and 40 (step S10). The channel information transmission / reception unit 110 that has received the channel information supplies the channel information to the channel selection unit 120. The channel information received from the other control device 30 (40) includes, for example, information indicating the communication mode used by the other control device 30 (40) and the channel used in each communication mode, and other control devices. 30 (40) includes information indicating the number of terminal stations accommodated in each communication mode.
  The channel observation unit 100 of the control device 10 observes the usage status by another system (step S20). The channel observation unit 100 that has observed the usage status supplies the observation information to the channel selection unit 120. Note that the channel observation unit 100 may observe the usage status in synchronization with the reception of the channel information by the channel information transmission / reception unit 110, or may observe the usage status asynchronously. When the channel observation unit 100 observes the usage status in synchronization with the reception of the channel information, for example, when the channel observation unit 100 acquires a notification that the channel information has been received from the channel information transmission / reception unit 110 that has received the channel information, Observe. Note that when the channel observation unit 100 observes the usage status asynchronously with the reception of the channel information, the order of step S10 and step S20 may be reversed.
  The channel selection unit 120 that has acquired the observation information from the channel observation unit 100 and has acquired the channel information from the channel information transmission / reception unit 110 uses the usage status of each channel by other systems indicated by the observation information and other information indicated by the channel information. Are used for communication with the terminal stations 20-1,..., 20-4 based on the usage status of each channel by the control devices 30 and 40 (step S30). Channel selection section 120 that has selected a channel to be used for communication with each terminal station 20-1,... 20-4, information indicating the selected channel, information indicating the number of terminal stations by communication mode, and channel observation section 100 The observation information acquired from is supplied to the channel information transmitting / receiving unit 110.
  The channel information transmission / reception unit 110, which has acquired information indicating the selected channel, information indicating the number of terminal stations by communication mode, and observation information from the channel selection unit 120, obtains channel information including these pieces of information from the terminal station 20-1, ..., transmitted to 20-4 and the other control devices 30 and 40 (step S40). And this flowchart is complete | finished. The channel information transmission / reception unit 110 may transmit channel information including only information indicating the selected channel to the terminal stations 20-1,..., 20-4.
  As described above, the control device 10 receives the channel information from the other control devices 30 and 40 so that the channel being used by the other control devices 30 and 40 and the channel used by the control device 10 do not overlap as much as possible. Determine the channel to use. Therefore, it is possible to suppress a decrease in throughput in communication with the terminal station. In particular, when the number of overlapping communication modes for each channel is derived based on the number of users (number of terminal stations) belonging to each communication mode, the channel is determined more accurately so as not to overlap, resulting in a decrease in throughput. Can be further suppressed. Further, since the control device 10 itself also transmits channel information to the other control devices 30 and 40, when the other control devices 30 and 40 have the same function as the control device 10, the other control devices 30 and 40 However, it is possible to suppress a decrease in throughput.
  In other words, according to the present invention, the channel information used is exchanged and shared among a plurality of adjacent control devices, and the channel usage overlaps with other adjacent control devices based on the exchanged and shared channel information. The channel is newly set or changed so as to minimize the. For example, when a new control device is activated, the control device newly sets a channel based on the exchanged channel information so that duplication of channel use with other adjacent control devices is minimized. In addition, the control device that has already been activated is set so as to minimize duplication of channel usage with other adjacent control information based on the channel information to be exchanged at the time of channel transition. Change the channel. As a result, channel duplication between a plurality of adjacent control devices is reduced, the entire channel is used evenly and efficiently, and throughput reduction due to channel duplication is eliminated. The throughput with the accommodated terminal is improved.
  By the way, as a method for efficiently sharing the same frequency band among a plurality of access points (control devices), when using an interference compensation method using spatial signal processing, which is used in a cellular system, a plurality of access points. Complex control is necessary for the points to operate in cooperation with each other. Therefore, it is generally not appropriate to apply to a wireless LAN that implements a simple system by independent distributed control.
  On the other hand, the control device 10 does not require a cooperative operation with other access points that require complicated control as described above, and suppresses a decrease in throughput as described above. Also in 40, a reduction in throughput can be suppressed.
  As described above, according to the present embodiment, it is possible to easily suppress a decrease in throughput due to channel contention in the plurality of control apparatuses 10, 30, and 40. In other words, high-quality wireless communication in the license-free zone is easily realized by this embodiment.
  In addition, the program for performing each process of the control apparatus 10 by one Embodiment of this invention is recorded on a computer-readable recording medium, and the program recorded on the said recording medium is read into a computer system, and is performed Accordingly, the above-described various processes related to each process of the control device 10 according to the embodiment of the present invention may be performed. Here, the “computer system” may include an OS and hardware such as peripheral devices. Further, the “computer system” includes a homepage providing environment (or display environment) if a WWW system is used. The “computer-readable recording medium” means a flexible disk, a magneto-optical disk, a ROM, a writable nonvolatile memory such as a flash memory, a portable medium such as a CD-ROM, a hard disk built in a computer system, etc. This is a storage device.
  Further, the “computer-readable recording medium” means a volatile memory (for example, DRAM (Dynamic DRAM) in a computer system that becomes a server or a client when a program is transmitted through a network such as the Internet or a communication line such as a telephone line. Random Access Memory)), etc., which hold programs for a certain period of time. The program may be transmitted from a computer system storing the program in a storage device or the like to another computer system via a transmission medium or by a transmission wave in the transmission medium. Here, the “transmission medium” for transmitting the program refers to a medium having a function of transmitting information, such as a network (communication network) such as the Internet or a communication line (communication line) such as a telephone line. The program may be for realizing a part of the functions described above. Furthermore, what can implement | achieve the function mentioned above in combination with the program already recorded on the computer system, and what is called a difference file (difference program) may be sufficient.
  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes designs and the like that do not depart from the gist of the present invention.
DESCRIPTION OF SYMBOLS 1 Radio | wireless communications system 10 Control apparatus 20-1, 20-2, 20-3, 20-4 Terminal station (terminal) 30, 40 Control apparatus 100 Channel observation part 110 Channel information transmission / reception part 130 Channel selection part

Claims (7)

  1. A control device for controlling a wireless communication system,
    A channel observation unit for observing the use status of other radio channels in a predetermined radio channel group by other systems;
    A channel information transmission / reception unit for receiving channel information indicating a use status of the radio channel by another control device constituting the radio communication system;
    A channel selection unit that selects a radio channel to be used for communication with each terminal from the radio channel group based on the usage status observed by the channel observation unit and the channel information received by the channel information transmission / reception unit; With
    The channel selector
    Selecting one or more radio channels that are not used by the other system and less used by the other control device from the radio channel group ;
    The wireless communication system includes:
    As a radio channel used by a plurality of control devices constituting the radio communication system and a terminal accommodated in each control device, a plurality of basic channels are defined,
    As a communication mode between the control device and the terminal, there are a plurality of communication modes in which the number of basic channels used for communication is different,
    Having one or more basic channels used redundantly in a plurality of communication modes between each control device and each terminal accommodated in each control device;
    The channel information received by the channel information transmitting / receiving unit is:
    Including information indicating a communication mode used by the other control device and a basic channel used in each communication mode;
    The channel selector
    Calculating the number of other devices used, which is the number of basic channels used by the other control device, for each basic channel;
    Total in one basic channel that is the maximum of the total number of used for each basic channel obtained by adding the number of used for each basic channel used in the control device to the number of other devices used for each basic channel A control apparatus that selects a radio channel to be used for communication with each terminal so that the number of uses is minimized .
  2. The channel selector
    The basic channel having the smallest number of other devices used is determined as the basic channel that is used redundantly, and the channel information transmitting / receiving unit receives the channel information, and the channel information is determined. Radio used for communication with each terminal so that the total number of the basic channels other than the basic channel to be transmitted / received is minimized in one basic channel, which is the maximum among the total number of used for each basic channel. The control device according to claim 1 , wherein a channel is selected.
  3. The channel information received by the channel information transmitting / receiving unit is:
    Further including information indicating the number of terminals using each communication mode used by the other control device,
    The channel selector
    Control device according to any one of claims 1 or claim 2, characterized in that to calculate the number of used the other apparatus by multiplying the number of the terminals for each of the basic channels.
  4. A control method for controlling a wireless communication system, comprising:
    Radio channel observation means for observing the usage status of other radio channels in a predetermined radio channel group by other systems;
    Channel information transmitting / receiving means for receiving channel information indicating the use status of the radio channel by other control devices constituting the radio communication system;
    Channel selection means for selecting a radio channel to be used for communication with each terminal from the radio channel group based on the use status observed by the radio channel observation means and the channel information received by the channel information transmitting / receiving means. And
    The channel selection means includes
    Selecting one or more radio channels that are not used by the other system and less used by the other control device from the radio channel group ;
    The wireless communication system includes:
    As a radio channel used by a plurality of control devices constituting the radio communication system and a terminal accommodated in each control device, a plurality of basic channels are defined,
    As a communication mode between the control device and the terminal, there are a plurality of communication modes in which the number of basic channels used for communication is different,
    Having one or more basic channels used redundantly in a plurality of communication modes between each control device and each terminal accommodated in each control device;
    The channel information received by the channel information transmitting / receiving means is
    Including information indicating a communication mode used by the other control device and a basic channel used in each communication mode;
    The channel selection means includes
    Calculating the number of other devices used, which is the number of basic channels used by the other control device, for each basic channel;
    Total in one basic channel that is the maximum of the total number of used for each basic channel obtained by adding the number of used for each basic channel used in the control device to the number of other devices used for each basic channel A control method comprising selecting a radio channel to be used for communication with each terminal so that the number of uses is minimized .
  5. The channel selection means includes
    The basic channel with the smallest number of other devices used is determined as the basic channel that is used redundantly, and the channel information transmitting / receiving means receives the channel information, and the channel information is Radio used for communication with each terminal so that the total number of the basic channels other than the basic channel to be transmitted / received is minimized in one basic channel, which is the maximum among the total number of used for each basic channel. 5. The control method according to claim 4 , wherein a channel is selected.
  6. The channel information received by the channel information transmitting / receiving means is
    Further including information indicating the number of terminals using each communication mode used by the other control device,
    The channel selection means includes
    The method according to any one of claims 4 or claim 5, characterized in that to calculate the number of used the other device for each of the basic channels by multiplying the number of the terminal.
  7. In a computer that controls a control device that controls a wireless communication system,
    A radio channel observation step of observing the use status of other radio channels in a predetermined radio channel group by other systems;
    A channel information transmission / reception step of receiving channel information indicating a use status of the radio channel by another control device constituting the radio communication system;
    A channel selection step of selecting a radio channel to be used for communication with each terminal from the radio channel group based on the usage status observed in the radio channel observation step and the channel information received in the channel information transmission / reception step. And a program for executing
    The channel selection step includes:
    Selecting one or more radio channels that are not used by the other system and less used by the other control device from the radio channel group ;
    The wireless communication system includes:
    As a radio channel used by a plurality of control devices constituting the radio communication system and a terminal accommodated in each control device, a plurality of basic channels are defined,
    As a communication mode between the control device and the terminal, there are a plurality of communication modes in which the number of basic channels used for communication is different,
    Having one or more basic channels used redundantly in a plurality of communication modes between each control device and each terminal accommodated in each control device;
    The channel information received by the channel information transmitting / receiving means is
    Including information indicating a communication mode used by the other control device and a basic channel used in each communication mode;
    The channel selection step includes:
    Calculating the number of other devices used, which is the number of basic channels used by the other control device, for each basic channel;
    Total in one basic channel that is the maximum of the total number of used for each basic channel obtained by adding the number of used for each basic channel used in the control device to the number of other devices used for each basic channel A program that selects a radio channel to be used for communication with each terminal so that the number of uses is minimized .
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