JP2007214713A - Wireless lan system, access point and channel control method and program for use therein - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an access point in which communication state with a terminal belonging to an AP subordinate before channel shift can be sustained even after channel shift. <P>SOLUTION: A radar detection information extracting section 331 starts processing based on its own radar detection notice received from a protocol processing section 32 or a Measurement Report frame reception notice from other AP, and outputs the radar detection notice or delivers channel information of radar detection and a management table update request. A radar detection channel management table 332 updates the management table to latest information and delivers a management table update completion notice. Upon receiving the management table update completion notice or a channel alteration request from a higher layer interface 4, a radar detection judging section 333 determines a shifted channel with reference to the management table and delivers a channel shift request and a BSS channel establishment notice. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wireless LAN system, an access point, a channel control method used therefor, and a program therefor, and more particularly, to a channel control method considering a DFS (Dynamic Frequency Selection) function in a wireless LAN (Local Area Network) system.

Conventionally, this type of wireless LAN system has been standardized by IEEE (Institute of Electrical and Electronic Engineers) 802.11 ^TM , and the standardized wireless LAN standard includes a wireless LAN system using a frequency of 5 GHz band. IEEE802.11h ^TM exists as a response to spectrum and transmission output regulation when operating in Europe, and two functions of TPC (Transmit Power Control) as a transmission output regulation and DFS as a spectrum regulation are defined. (For example, refer nonpatent literature 1).

  More specifically, the TPC function implements a transmission output control function to reduce the influence of interference on a satellite system using the same frequency band, and the DFS function uses the same channel as a radar system using the same frequency band. The wireless LAN system side is obliged to implement a radar detection function and a channel movement function to avoid operation.

  In Japan, the frequency band newly allocated to the 5 GHz band wireless access system from May 2005 is partly because it is a band already allocated to weather radar and various radars. It is obliged to implement a TPC function and a DFS function in an AP (Access Point) of a wireless LAN system that uses a frequency band.

  In addition, specific domestic regulations are based on TELE (TELecom Engineering Center), and this detail is equivalent to the contents defined in ETSI (European Telecommunications Standards Institute), which is a European standard, and is a channel in which radar detection is performed by the DFS function. The operation prohibition within 30 minutes and the radar search for 60 seconds before starting the operation on the channel whose radar presence / absence information is not known in advance are essential.

  Since the channel determination process is implementation-dependent within the above-mentioned regulations concerning the DFS function, the AP can detect radar detection and channel dynamics unless it implements radar presence / absence information related to channels other than in operation by a unique method. It is essential to perform a radar search for 60 seconds before the start of operation on the transition destination channel accompanying the change. As a result, a no-communication state is generated with the belonging terminal, and therefore there is an operational problem that it is difficult to continue the communication state before and after channel transition that occurs when radar is detected on the channel in operation. is there.

IEEE802.11hTM-2003, “5. General description” (p.3-5)

The DFS function specified by IEEE 802.11h ^TM implements a radar wave detection function on the wireless LAN system side and starts operation of the wireless LAN system so that the wireless LAN system is not operated in the same frequency band as the radar system. When a radar wave is detected at the time and during operation, the mobile station shifts to another channel where the radar is not operated, and the AP transmits a beacon frame to the destination channel information for the terminal belonging to the AP. It is stipulated that it is notified using.

  In addition, according to the ETSI regulations in Europe, regarding this wireless LAN system operation, operation within 30 minutes is prohibited in a channel where radar detection by the DFS function is performed, and operation for 60 seconds before starting operation on a channel whose radar presence / absence information is not known in advance. Radar search is essential.

  In the above rules, there is no clear definition regarding the channel determination procedure, and the domestic TELEC content conforms to the ETSI rule, so the AP does not independently implement radar presence / absence information on other channels that are not in operation. As long as it is necessary to perform a radar search for 60 seconds before the start of operation on the destination channel associated with radar detection or channel dynamic change, there will always be no communication.

  Therefore, in the conventional wireless LAN system, when radar detection is performed on a channel in operation, or when an AP starts operation on a new channel due to dynamic channel change, the attribution of a terminal belonging to the AP There is a problem that the communication state with the belonging terminal cannot be continued before and after the AP channel shift.

  Therefore, an object of the present invention is to solve the above-described problems and to maintain a communication state with a terminal belonging to an AP under a channel before the channel shift even after the channel shift, a wireless LAN system, an access point, and a channel used for them A control method and a program thereof are provided.

A wireless LAN system according to the present invention includes an access point having a DFS (Dynamic Frequency Selection) function having a radar detection function and a channel movement function for avoiding operation on the same channel as a radar system using the same frequency band, A wireless LAN (Local Area Network) system that operates in a frequency band in which the DFS function is essential,
The access point includes a radar detection channel management table that stores at least channel information and a detection result of the radar system in association with each other, and a channel shift by the channel movement function by radar detection by the radar detection function and an arbitrary case. Means for performing channel determination based on information in the radar detection channel management table when performing channel change, radar detection results from the radar detection function and radar detection information notification received from other surrounding access points; And a means for dynamically updating the radar detection channel management table based on

An access point according to the present invention has a DFS (Dynamic Frequency Selection) function having a radar detection function and a channel movement function for avoiding operation on the same channel as a radar system using the same frequency band, and the DFS function is essential. An access point used in a wireless LAN (Local Area Network) system operating in a different frequency band,
A radar detection channel management table that stores at least channel information and detection results of the radar system in association with each other, a case of performing channel transition by the channel movement function by radar detection by the radar detection function, and a case of performing arbitrary channel change Based on information in the radar detection channel management table, radar detection results from the radar detection function, and radar detection information notifications received from other access points in the vicinity. Means for dynamically updating the detection channel management table.

A channel control method according to the present invention includes an access point having a DFS (Dynamic Frequency Selection) function having a radar detection function and a channel movement function for avoiding operation on the same channel as a radar system using the same frequency band, A channel control method used in a wireless LAN (Local Area Network) system that operates in a frequency band in which the DFS function is essential,
The access point performs channel transition by the channel movement function by radar detection by the radar detection function based on information in a radar detection channel management table that stores at least channel information and a detection result of the radar system in association with each other. The radar detection channel based on a process for determining a channel in any of the case and an arbitrary channel change, a radar detection result by the radar detection function, and a radar detection information notification received from other surrounding access points The management table is dynamically updated.

The program of the channel control method according to the present invention includes an access point having a DFS (Dynamic Frequency Selection) function having a radar detection function and a channel movement function for avoiding operation on the same channel as a radar system using the same frequency band. A program for realizing a channel control method used in a wireless LAN (Local Area Network) system that operates in a frequency band in which the DFS function is essential,
On the computer,
When channel transition is performed by the channel movement function by radar detection by the radar detection function based on information in a radar detection channel management table that stores at least channel information and detection results of the radar system in association with each other and arbitrary channel change The radar detection channel management table is dynamically determined based on the processing for determining the channel in any of the cases where the radar detection is performed, the radar detection result by the radar detection function, and the radar detection information notification received from other surrounding access points. The process to update is executed.

That is, the channel control method of the present invention is a radar using a wireless LAN (Local Area Network) system using a frequency 5 GHz band defined by IEEE (Institute of Electrical and Electronic Engineers) 802.11 ^TM and using the same frequency band. When operating in a frequency band in which a DFS (Dynamic Frequency Selection) function having a radar detection function and a channel movement function for avoiding operation on the same channel as the system is used, an AP (Access Point) having this DFS function is provided. Point), when the channel is moved by radar detection, or the channel is determined when any channel is changed, the radar detection channel management owned by the device itself The radar detection channel management table is dynamically updated based on the radar detection result of the device itself and the radar detection information notification received from other surrounding APs.

Here, in order to prevent the wireless LAN system from being operated in the same frequency band as that of the radar system, the DFS function defined by IEEE802.11h ^TM includes an implementation of a radar wave detection function on the wireless LAN system side, and a wireless LAN system. When a radar wave is detected at the start of operation of the system and during operation, the channel shifts to another channel where the radar is not operated, and further, the AP is transferred to the channel belonging to the AP. Is notified using a beacon frame.

When more specifically described with reference to FIG. 1, the IEEE 802.11 ^TM is the standard of a wireless LAN system, AP # 1, # 2 each terminal station belonging to thereunder: configured with (STA Station) Communication The area is called BSS (Basic Service Set). When both BSS # 1 and # 2 are operating in a frequency band requiring a DFS function based on IEEE802.11h ^TM , each AP detects a radar wave in its operating channel, and radar detection It sometimes has a radar detection information notification transmission function for transmitting a radar detection information notification to other APs.

  For example, when AP # 1 detects a radar wave and transmits a radar detection information notification to AP # 2, AP # 2, which has received the radar detection information notification, updates its own radar detection channel management table. . Note that the channel on which the radar detection AP # 1 transmits the radar detection information notification is all channels that can be operated by the AP # 1, and thereby a wireless LAN constituted by a plurality of APs having this function. In the system, each AP can always hold the latest radar detection channel information.

  As a result, in the channel control method of the present invention, the channel shift destination determination in the AP operating in the frequency band in which the DFS function is effective, and the radar detection channel management table that is referred to when the channel shift destination is determined are variously related to the DFS function. By managing based on the regulations, it is possible to previously hold the latest radar presence / absence information for a channel that can be operated by the AP.

  Therefore, in the channel control method of the present invention, it is possible to immediately determine the destination channel associated with the radar detection or the channel change during operation, and the radar search process for 60 seconds before the start of the operation in the destination channel becomes unnecessary. Therefore, in the channel control method according to the present invention, it is possible to immediately start operation on a new channel after channel transition associated with radar detection and after channel transition processing associated with channel change during operation. It becomes possible to continue the communication state with terminals belonging to the AP even after the channel shift.

  By adopting the configuration and operation as described above, the present invention provides an effect that the communication state with the terminal belonging to the AP before the channel shift can be continued even after the channel shift.

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing the configuration of a wireless LAN (Local Area Network) system according to an embodiment of the present invention. In FIG. 1, a wireless LAN system according to an embodiment of the present invention includes APs (# 1, # 2) (Portal) 1-1, 1-2 having DFS (Dynamic Frequency Selection) function, and STAs belonging to the APs (# 1, # 2). station: IEEE consists terminal station) 2-1 to 2-5 Prefecture (Institute of Electrical and Electronic Engineers) is Infrastructure Network defined in 802.11 ^TM.

The Portals of AP (# 1, # 2) 1-1, 1-2 shown in FIG. 1 have a protocol conversion function with a LAN protocol other than IEEE 802.11 ^™. 1, 1 to 2 indicates a base station terminal that enables connection between a wireless base station terminal and wired LANs 101 and 102 such as Ethernet (registered trademark).

In IEEE 802.11 ^TM is a standard for wireless LAN, AP (# 1, # 2) 1-1,1-2 is, a communication area configured with STA2-1~2-5 attributable to its subordinate, BSS (Basic Service Set) 201, 202.

When the BSSs 201 and 202 are both operating in a frequency band that requires a DFS function based on IEEE 802.11h ^TM , each AP (# 1, # 2) 1-1 and 1-2 is in its own operating channel. It has a function of detecting a radar wave and a radar detection information notification transmission function of transmitting a radar detection information notification 301 to another AP at the time of radar detection.

  FIG. 1 shows that AP (# 1) 1-1 detects a radar wave and transmits a radar detection information notification 301. AP (# 2) 1-1 that has received this radar detection information notification 301 is shown. 2 updates its own radar detection channel management table. Note that the channels on which the AP (# 1) 1-1 that has performed radar detection transmits the radar detection information notification 301 are all channels that can be operated by the AP (# 1) 1-1. As a result, in a wireless LAN system constituted by a plurality of APs having the function, each AP can always hold the latest radar detection channel information.

  FIG. 2 is a block diagram showing a configuration example of AP (# 1, # 2) 1-1, 1-2 in FIG. In FIG. 2, APs (# 1, # 2) 1-1 and 1-2 are connected to a TCP / IP (Transmission Control Protocol / Internet Protocol) or various types via an interface 4 between the wireless LAN module 3 and an upper layer. An upper protocol process such as an application is realized by the radio base station or the mobile terminal body 5.

  Also, the STAs 2-1 to 2-5 shown in FIG. 1 have APs (# 1, # 2) 1-1, 1-2 via the wireless LAN module 3 shown in FIG. Similar upper-level protocol processing is realized by a radio base station such as a notebook personal computer or the mobile terminal body 5.

The wireless LAN module 3 shown in FIG. 2 includes a wireless unit 31 that performs frame transmission / reception in a wireless section, and an IEEE 802.11 ^™ PHY (Physical Layer) & MAC (Medium) that performs modulation / demodulation processing and access control based on the IEEE 802.11 ^™ standard. An access control (protocol processing unit) 32 (hereinafter referred to as a protocol processing unit) 32 and an upper layer processing unit 33 that implements SME (station management entity) processing such as authentication in the MAC layer.

At the time of frame transmission, the protocol processing unit 32 performs conversion and modulation processing on the transmission request frame received from the upper layer processing unit 33 into a MAC frame format according to the IEEE 802.11 ^™ MAC protocol, and passes this through the radio unit 31. The transmission process is completed by sending the frame onto the space.

  When receiving a frame, the protocol processing unit 32 performs demodulation processing on the frame received from the radio unit 31, calculation of CRC (Cyclic Redundancy Check) 32 on the received MAC frame, MAC header analysis, and processing on the received frame. The frame body part is notified to the upper layer processing part 33.

  The APs (# 1, # 2) 1-1, 1-2 constituting the BSSs 201, 202 are connected to the STAs 2-1 to 2-5 in the BSSs 201, 202 by the AP (# 1, # 2) 1-1, 1- 2 periodically transmits a Beacon frame including information for synchronizing with BSS 201 and 202 of its own device. The Beacon frame format includes a “MAC header (Header)” part, a “Frame Body” part, and an “FCS (Frame Check Sequence)” field, and the “Frame Body” part includes BSS 201, “Timestamp” required for synchronization in 202, “Beacon Interval” indicating the Beacon frame transmission cycle, “Capability Information” indicating the attribute information of AP (# 1, # 2) 1-1, 1-2, and various “ An "Information element" field is included.

  In FIG. 3, the “MAC header” portion includes “Frame Control”, “Duration”, “DA (tin Address to Des)”, “SA (Source Address)”, “BSS ID (IDentifier)”, “Sequence Control”. ”Fields are included.

  The “Frame Body” field includes fields of “Timestamp”, “Beacon Interval”, “Capability Information”, various “Information elements”, and “Channel Switch Announcement”.

  Further, the fields of “Channel Switch Announcement” include “Element ID”, “Length”, “Channel Switch Mode”, “Channel Switch Number”, and “Channel Switch Count”.

  The “Channel Switch Annunciation element”, which is one of the “Information element” fields described above, indicates the destination channel information at the time of radar detection as STAs 2-1 to APs (# 1, # 2) 1-1 and 1-2. Used to notify 2-5.

As a specific means for notifying radar detection information in this embodiment, a Measurement Report frame defined in IEEE802.11h ^TM is used, and details of this frame format are shown in FIG.

  The Measurement Report frame is defined as a frame for the AP to notify the surrounding AP or terminal of the result of the radio state measurement in an arbitrary channel, and the result of checking the presence or absence of a radar wave as the radio state measurement. Can notify the radar wave detection channel using the “Channel Number” field in the Measurement Report field and the presence or absence of radar detection using the “Radar” bit in the “Map” field.

  In FIG. 4, the Measurement Report frame format includes a “MAC header” part, a “Frame Body” part, and an “FCS” field. The “MAC header” section includes fields of “Frame Control”, “Duration”, “DA”, “SA”, “BSS ID”, and “Sequence Control”.

  Further, the “Frame Body” part includes the fields “Category”, “Action”, “Dialog Token”, and “Measurement Report elements”, and the field “Measurement Report elements” includes the element “ID”. "," Length "," Measurement Token "," Measurement Report Mode "," Measurement Type ", and" Measurement Report ".

  In addition, the “Measurement Report” field includes the “Channel Number”, “Measurement Start time”, “Measurement Duration”, and “Map” fields, and the “Map” field includes “BSS” and “Map” fields. Each field includes “OFDM Preamble”, “Unidentified Signal”, “Radar”, “Unmeasured”, and “Reserved”.

  In this embodiment, as shown in FIG. 1, the AP (# 1) 1-1 that has performed radar detection updates its own radar detection channel management table and transmits a radar detection information notification 301 to the surroundings. The surrounding AP (# 2) 1-2 that has received the radar detection information notification 301 updates its radar detection channel management table to the latest information.

  Also, each of AP (# 1, # 2) uses this radar detection channel management table to determine the destination channel when performing subsequent radar detection generation or dynamic channel change.

  FIG. 5 is a block diagram showing a configuration of the upper layer processing unit 33 of FIG. In FIG. 5, the upper layer processing unit 33 includes a radar detection information extraction processing unit 331, a radar detection channel management table 332, and a radar detection determination unit 333.

  The radar detection information extraction processing unit 331 starts the process by receiving its own radar detection notification received from the protocol processing unit 32 or a Measurement Report frame reception notification from another AP that has performed radar detection. A management table update request for the radar detection channel management table 332 is transmitted together with the output of the radar detection notification to 333 and the channel information on which radar detection has been performed.

  The radar detection channel management table 332 updates the radar detection channel management table to the latest information in response to the management table update request accompanied by the radar detection channel information received from the radar detection information extraction processing unit 331, and determines whether the management table update completion notification is detected by radar detection. The data is sent to the unit 333.

  The radar detection determination unit 333 receives the management table update completion notification from the radar detection channel management table 332 or the channel change request from the upper layer interface 4 and determines the destination channel by referring to the radar detection channel management table 332. And a channel transition request or a BSS establishment channel notification to the protocol processing unit 32 is transmitted.

  The radar detection determination unit 333 uses all the channels that can be operated by the AP by outputting a measurement report frame transmission request addressed to the protocol processing unit 32 before the channel shift due to radar detection in the BSS of the own device. Thus, the radar detection information notification 301 is performed for the surrounding APs.

  6 is a flowchart showing the processing operation of the radar detection information extraction processing unit 331 of FIG. 5, FIG. 7 is a diagram showing the configuration of the radar detection channel management table 332 of FIG. 5, and FIG. 8 is the radar detection of FIG. 9 is a flowchart showing the processing operation of the channel management table 332, and FIG. 9 is a flowchart showing the processing operation of the radar detection determination unit 333 of FIG. The processing operation of the upper layer processing unit 33 will be described with reference to FIGS.

  The radar detection information extraction processing unit 331 receives a radar detection notification or a measurement report frame from the protocol processing unit 32 (step S1 in FIG. 6), and determines that it is reception of a radar detection notification (step in FIG. 6). S2) After outputting the radar detection notification to the radar detection determination unit 333 (step S3 in FIG. 6) and confirming the channel number currently in operation (step S4 in FIG. 6), the management table for the radar detection channel management table 332 Output update request.

  When the radar detection information extraction processing unit 331 determines that the measurement report frame reception notification has been received from the protocol processing unit 32 (step S2 in FIG. 6), it extracts the channel number field and the radar bit in the measurement report frame (FIG. 6). 6 step S5). When the radar detection information extraction processing unit 331 confirms that the value of the Radar bit is “1” (step S6 in FIG. 6), it outputs a management table update request to the radar detection channel management table 332, and sets the Radar bit. When it is confirmed that the value is not “1” (step S6 in FIG. 6), the process associated with the radar detection is stopped, and the process shifts to a state of waiting for the radar detection or measurement report frame reception notification again.

  As shown in FIG. 7, the radar detection channel management table 332 includes “channel information (52ch, 56ch, 60ch, 64ch,...)” And “elapsed time from radar detection time (2 minutes 30 seconds) for each channel. , 25 minutes, 0 seconds, 0 seconds,...) "And status management of the presence / absence of radar detection [" radar detection (yes / no) "]. 30 minutes based on ETSI default.

  The radar detection channel management table 332 starts processing upon reception of a management table update request from the radar detection information extraction processing unit 331 or notification of expiration of elapsed time from the radar detection time generated in the radar detection channel management table. When the radar detection channel management table 332 confirms reception of the management table update request (step S11 in FIG. 8), the radar detection channel information is confirmed (step S12 in FIG. 8), and the radar detection in the current channel management table for the channel is detected. The status is confirmed (step S13 in FIG. 8).

  If the radar detection channel management table 332 is already “detected”, the elapsed time information from the detection time for the channel is returned to “0” (step S14 in FIG. 8), and the management table update completion notification is sent to the radar detection determination unit. To 333. Further, the radar detection channel management table 332 changes the radar detection status to “with detection” when the radar detection status in the current channel management table for the channel is “no detection” (step S15 in FIG. 8). The elapsed time counting from the detection time is started (step S16 in FIG. 8).

  When the radar detection channel management table 332 receives a notification of expiration of elapsed time from the radar detection time in the radar detection channel management table (step S11 in FIG. 8), the radar detection status of the channel is changed from “detected” to “ It changes to “no detection” (step S17 in FIG. 8), resets the elapsed time information from the detection time to “0”, and stops the counting process (step S18 in FIG. 8).

  The radar detection determination unit 333 starts processing upon receiving a management table update completion notification from the radar detection channel management table 332 or receiving a channel change request from the upper layer interface 4. The radar detection determination unit 333 confirms reception of the management table update completion notification (step S21 in FIG. 9), and confirms that no radar detection notification is received from the radar detection information extraction processing unit 331 (step S22 in FIG. 9). Then, an arbitrary channel whose radar detection status is “no detection” is selected from the radar detection channel management table 332, and a channel shift request is output to the protocol processing unit 32 (step S25 in FIG. 9).

  Further, when the radar detection determination unit 333 confirms that the radar detection notification is received from the radar detection information extraction processing unit 331 (step S22 in FIG. 9), a management report frame transmission request is output to the protocol processing unit 32. Then, after receiving the Management Report frame transmission completion notification, channel transition processing is performed (steps S23 to S25 in FIG. 9).

  When the confirmation result of the management table update completion notification is reception of a channel change request from the upper layer interface 4 (step S21 in FIG. 9), the radar detection determination unit 333 detects the radar of the channel designated as the channel change request destination. The status is confirmed by referring to the radar detection channel management table 332 (step S26 in FIG. 9).

  When the radar detection status of the designated channel is “detected”, the radar detection determination unit 333 determines and confirms the BSS establishment channel from the “no radar detected” channel in the radar detection channel management table 332. (Step S27 in FIG. 9), BSS opening channel notification is output. In addition, when the radar detection determination unit 333 confirms that there is no radar detection in the designated channel (step S26 in FIG. 9), the BSS establishment using the channel designated from the upper layer interface 4 as the channel for BSS establishment is performed. A channel notification is output to the protocol processing unit 32 (step S28 in FIG. 9).

  As described above, in this embodiment, the AP (# 1, # 2) 1-1, 1-2 operating in the frequency band requiring the DFS function performs channel transition by radar detection, or an arbitrary channel change. Is determined based on the information of the radar detection channel management table 332 owned by itself, and the radar detection result of the radar detection channel management table 332 received from its own radar detection result and other surrounding APs By dynamically updating based on the information notification, in the AP operation according to European ETSI and domestic TELEC regulations, the channel information management that can be used inside the AP is not limited to its own radar detection results, The latest information on available channels can be maintained by appropriately updating the radar detection information received from the AP. It is possible.

  As a result, in this embodiment, it is possible to delete the radar search process for 60 seconds before the start of operation on the channel whose radar presence / absence information is not known in advance, which is defined in ETSI, and the AP opens the BSS in the destination channel. Can be performed immediately, so that the belonging state with the STA can be maintained before and after channel transition. In addition, in this embodiment, even when the radar detection channel is banned from operating within 30 minutes, the elapsed time from the radar detection time is self-managed so that at the time of radar detection or when a channel transition request is received. It is possible to appropriately determine the channel that can be transferred.

  Furthermore, in this embodiment, a plurality of APs (# 1, # 2) 1-1, 1- 1 having the radar detection information extraction processing unit 331, the radar detection channel management table 332, and the radar detection determination unit 333 are used. In a wireless LAN network composed of two, radar detection information common to each AP (# 1, # 2) 1-1 and 1-2 existing in an area where communication between APs is possible by transmitting a radar detection information notification Since it becomes possible to hold the channel management table 332, it is possible to avoid the channel during radar operation even though each AP (# 1, # 2) 1-1, 1-2 is operating independently. Operation using the remaining channels without the radar can be unified for the entire wireless LAN network.

  In the present invention, the radar detection channel management table 332 has functions of AP (# 1, # 2) 1-1 and 1-2 in the above embodiment, but the radar detection channel management table 332 is AP (# 1, # 2) It is not a function of 1-1, 1-2, but is connected to AP (# 1, # 2) 1-1, 1-2 via a wired network, and a plurality of APs (# 1, # 2 2) A function of a policy server (not shown) that performs collective management of information of 1-1, 1-2 and remote control of operations of each AP (# 1, # 2) 1-1, 1-2. Is also possible.

  In this case, between the APs (# 1, # 2) 1-1, 1-2 and the policy server, the presence / absence of radar detection, channel setting information, destination channel information, etc. are presented in one embodiment of the present invention. It is necessary to prepare a new interface required for channel change control.

  When a notification with radar detection occurs from any AP managed by the policy server, or when a request for channel change occurs, the policy server determines the surrounding environment such as location information and operating frequency of each AP managed by the policy server. In consideration of this, it is possible to determine the destination channel in consideration of the channel arrangement of the entire wireless LAN network.

  Further, in the present invention, by using the above policy server or other methods, all of the wireless LAN networks configured by a plurality of APs (# 1, # 2) 1-1 and 1-2 are used. When the AP (# 1, # 2) 1-1, 1-2 is in a synchronized state, the AP that has received the radar detection information notification using the Measurement Report frame shown in FIG. 4 from any neighboring AP However, the elapsed time management from the detection time in the radar detection channel management table 332 shown in FIG. 5 is more accurately performed using the setting values of each field of “Measurement Start Time” and “Measurement Duration” in the Measurement Report frame. It can also be possible.

It is a block diagram which shows the structure of the wireless LAN system by one Example of this invention. It is a block diagram which shows the structural example of AP of FIG. It is a figure which shows the format of a Beacon frame. It is a figure which shows the format of Measurement Report frame. It is a block diagram which shows the structure of the upper layer process part of FIG. It is a flowchart which shows the processing operation of the radar detection information extraction process part of FIG. It is a figure which shows the structure of the radar detection channel management table of FIG. It is a flowchart which shows the processing operation of the radar detection channel management table of FIG. It is a flowchart which shows the processing operation of the radar detection determination part of FIG.

Explanation of symbols

1-1, 1-2 AP (# 1, # 2)
2-1 to 2-5 STA
3 Wireless LAN module
4 Interface with higher layers
5 Radio base station or mobile terminal
31 Radio unit
32 IEEE 802.11 ^™ PHY & MAC Protocol Processing Unit
33 Upper layer processing unit 101, 102 LAN
331 Radar detection information extraction processing unit
332 Radar detection channel management table
333 Radar detection determination unit

Claims (13)

A frequency band including an access point having a DFS (Dynamic Frequency Selection) function having a radar detection function and a channel movement function for avoiding operation on the same channel as a radar system using the same frequency band, and in which the DFS function is essential A wireless LAN (Local Area Network) system operated by
The access point includes a radar detection channel management table that stores at least channel information and a detection result of the radar system in association with each other, and a channel shift by the channel movement function by radar detection by the radar detection function and an arbitrary case. Means for performing channel determination based on information in the radar detection channel management table when performing channel change, radar detection results from the radar detection function and radar detection information notification received from other surrounding access points; And a means for dynamically updating the radar detection channel management table based on the wireless LAN system.   The wireless LAN system according to claim 1, wherein the radar detection function detects a radar wave in an operating channel.   The wireless LAN system according to claim 2, wherein the access point includes means for transmitting the radar detection information notification to the other access points in the vicinity when the radar wave is detected by the radar detection function.   4. The wireless LAN system according to claim 3, wherein the access point uses all channels operable by its own device as channels for transmitting the radar detection information notification. Radio having a DFS (Dynamic Frequency Selection) function having a radar detection function and a channel moving function for avoiding operation on the same channel as a radar system using the same frequency band, and operating in a frequency band in which the DFS function is essential An access point used in a LAN (Local Area Network) system,
A radar detection channel management table that stores at least channel information and detection results of the radar system in association with each other, a case of performing channel transition by the channel movement function by radar detection by the radar detection function, and a case of performing arbitrary channel change Based on information in the radar detection channel management table, radar detection results from the radar detection function, and radar detection information notifications received from other access points in the vicinity. Means for dynamically updating the detection channel management table.   6. The access point according to claim 5, wherein the radar detection function detects a radar wave in an operating channel.   The access point according to claim 6, further comprising means for transmitting the radar detection information notification to the other access points in the vicinity when the radar wave is detected by the radar detection function.   8. The access point according to claim 7, wherein all channels that can be operated by the device are used as channels for transmitting the radar detection information notification. A frequency band including an access point having a DFS (Dynamic Frequency Selection) function having a radar detection function and a channel movement function for avoiding operation on the same channel as a radar system using the same frequency band, and in which the DFS function is essential A channel control method used in a wireless LAN (Local Area Network) system operated in
The access point performs channel transition by the channel movement function by radar detection by the radar detection function based on information in a radar detection channel management table that stores at least channel information and a detection result of the radar system in association with each other. The radar detection channel based on a process for determining a channel in any of the case and an arbitrary channel change, a radar detection result by the radar detection function, and a radar detection information notification received from other surrounding access points A channel control method, comprising: dynamically updating a management table.   The channel control method according to claim 9, wherein the radar detection function detects a radar wave in an operating channel.   The channel control method according to claim 10, wherein the access point performs a process of transmitting the radar detection information notification to the other access points in the vicinity when the radar wave is detected by the radar detection function.   12. The channel control method according to claim 11, wherein the access point uses all channels operable by its own device as channels for transmitting the radar detection information notification. A frequency band including an access point having a DFS (Dynamic Frequency Selection) function having a radar detection function and a channel movement function for avoiding operation on the same channel as a radar system using the same frequency band, and in which the DFS function is essential A program for realizing a channel control method used in a wireless LAN (Local Area Network) system operated by
On the computer,
When channel transition is performed by the channel movement function by radar detection by the radar detection function based on information in a radar detection channel management table that stores at least channel information and detection results of the radar system in association with each other and arbitrary channel change The radar detection channel management table is dynamically determined based on the processing for determining the channel in any of the cases where the radar detection is performed, the radar detection result by the radar detection function, and the radar detection information notification received from other surrounding access points. A program for executing update processing.

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