Node, system, method, and program

Abstract

A node used in a wireless backhaul system according to the present invention is provided with: an access line communication unit that communicates with a terminal device using a first channel; a backhaul communication unit that communicates with an adjacent node using a second channel and transmits listening channel information indicating a third channel to the adjacent node; and a monitoring unit that monitors a radar wave for the third channel.

Description

Technical Field

[0001] The present disclosure relates to nodes, systems, methods, and programs. Background Art

[0002] Japanese laws and regulations require that nodes conducting wireless communications in the 5GHz band have a function that, upon detecting radar waves, such as those from weather radar, terminates communication within 10 seconds and switches to a different channel where radar waves are not detected. This function is called DFS (Dynamic Frequency Selection).

[0003] In addition, in accordance with laws and regulations, when a node changes to a new channel, it must perform radar wave detection for 1 minute before using the new channel (hereinafter referred to as "monitoring"). In addition, the channel where radar waves are detected cannot be used for communication within 30 minutes after the radar waves are detected.

[0004] Therefore, in order to shorten the time of communication interruption, a process called high-speed DFS is performed, that is, the node monitors radar waves in advance for channels that are not in use, and when radar waves are detected on the channel in use, the channel that has been monitored in advance (hereinafter referred to as the "monitoring channel") is used.

[0005] Patent document 1 describes the following invention: When an AP (Access Point) detects radar waves, it updates the management table and sends a management table update request via the priority LAN (priority local area network). Each AP thus maintains a common management table, thereby being able to continue communicating with the affiliated terminal even after the channel is transferred.

[0006] Patent Document 2 describes an invention in which, when radar waves are detected, existing AP information is notified to a home terminal, and the terminal switches the connection destination AP, thereby enabling continued communication.

[0007] Patent Document 3 describes an invention that shortens the beacon transmission interval for performing DFS in an Ad-hoc mode in a multi-hop environment, thereby enabling notification of radar wave detection within 10 seconds before disconnection.

[0008] Patent document 4 describes the following invention: radar waves are monitored in advance on an unused channel. When radar waves are detected on the access channel used in communication between each AP and the terminal, each AP switches to the channel where radar waves are being monitored and uses it as the access channel.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-214713

[0012] Patent Document 2: Japanese Patent Application Laid-Open No. 2008-011387

[0013] Patent Document 3: Japanese Patent Application Laid-Open No. 2009-141901

[0014] Patent Document 4: Japanese Patent Application Laid-Open No. 2010-278825 Summary of the Invention

[0015] In a wireless backhaul system, which builds a network of wirelessly connected nodes (hereinafter referred to as a "mesh network"), all nodes use the same channel to connect to other nodes. Therefore, if a node (e.g., Node X) in the wireless backhaul system detects radar waves on the channel it is using, at least that node must change to a different channel in accordance with regulations.

[0016] As mentioned above, regulations require each node to monitor radar waves for one minute. Therefore, a node that detects radar waves may experience a disconnection lasting more than one minute before completing a channel change. Therefore, in wireless backhaul systems, it is desirable to shorten the duration of communication interruptions.

[0017] However, if channels are switched based on the node that detects radar waves, nodes using multiple channels will coexist in the same wireless backhaul system, making it difficult to maintain a mesh communication network. To date, research has not yet been conducted on high-speed DFS in wireless backhaul systems where all nodes use the same channel.

[0018] In one embodiment, a node used in a wireless backhaul system includes: an access line communication unit that communicates with a terminal device using a first channel; a backhaul line communication unit that communicates with an adjacent node using a second channel and sends monitoring channel information indicating a third channel to the adjacent node; and a monitoring unit that monitors radar waves on the third channel.

[0019] A wireless backhaul communication system in one embodiment includes a first node and a second node, wherein the first node has: a first access line communication unit that communicates with a terminal device using a first channel; a first backhaul line communication unit that communicates with an adjacent node using a second channel; a first monitoring unit that monitors a third channel for radar waves; and a first control unit that sets the third channel and causes the first backhaul line communication unit to send monitoring channel information indicating the third channel to the adjacent node, and the second node has: a second access line communication unit that communicates with a terminal device using a fourth channel; a second backhaul line communication unit that communicates with an adjacent node using the second channel; a second monitoring unit that monitors the third channel for radar waves; and a second control unit that causes the second backhaul line communication unit to forward the monitoring channel information indicating the third channel to the adjacent node when the second backhaul line communication unit receives the monitoring channel information.

[0020] Effects of the Invention

[0021] According to a non-limiting embodiment of the present disclosure, all nodes constituting the wireless backhaul system monitor the same monitoring channel. When radar waves are detected in the channel being used, all nodes change to the same monitoring channel together, thereby enabling rapid resumption of communication based on the wireless backhaul system. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a diagram showing a configuration example of a wireless communication system.

[0023] Figure 2 Is a block diagram representing the internal structure of a node.

[0024] Figure 3 This is a flowchart showing the operation of CN.

[0025] Figure 4 It is a flowchart showing the operation of SN.

[0026] Figure 5 It is a sequence diagram showing the operation of each node. DETAILED DESCRIPTION

[0027] Hereinafter, the embodiment will be described with reference to the accompanying drawings as appropriate. Throughout this specification, the same elements will be denoted by the same reference numerals unless otherwise specified. Figure 1 The matters described above are for explaining exemplary embodiments and are not intended to represent the only embodiments. For example, when the order of actions is shown in the embodiments, the order of actions may be appropriately changed within the scope of the overall action without causing any contradiction.

[0028] When multiple embodiments and / or variations are illustrated, part of the structure, function and / or action of a certain embodiment and / or variation may be included in other embodiments and / or variations to the extent that no conflict occurs, or may be replaced by corresponding structure, function and / or action of other embodiments and / or variations.

[0029] In addition, in the embodiments, overly detailed descriptions may be omitted. For example, detailed descriptions of well-known or commonly known technical matters may be omitted to avoid unnecessary redundancy and / or to obscure technical matters or concepts, thereby facilitating understanding by those skilled in the art. Furthermore, repetitive descriptions of substantially identical structures, functions, and / or operations may be omitted.

[0030] The purpose of providing the drawings and the following description is to help understand the embodiments and is not intended to limit the subject matter described in the claims. In addition, the terms used in the following description can also be appropriately replaced with other terms to help those skilled in the art understand.

[0031] <System Configuration Example>

[0032] Figure 1 1 is a diagram showing a configuration example of a wireless communication system according to an embodiment. Figure 1 The wireless communication system 1 shown includes a plurality of nodes 3 and a terminal device 7. Figure 1 In the example, eight nodes 3 are shown, numbered #0 to #7, as a non-limiting example. Terminal devices 7 can be connected to the nodes 3. The number of nodes 3 can be 2 or more and less than 7, or 9 or more. The number of terminal devices 7 does not need to be 2; multiple terminal devices can be connected to a single node.

[0033] Each node 3 is an example of a wireless device capable of wireless communication. Therefore, each node 3 may also be referred to as a "wireless node 3." Wireless communication can employ communication protocols that comply with (or are based on) wireless LAN (Local Area Network) standards such as IEEE 802.11b / g / a / n / ac / ad / ay / ax.

[0034] Each node 3 forms an area where wireless communication is possible. A "wireless communication area" may also be referred to as a "wireless communication area," "wireless area," "communication area," "service area," "coverage area," or "covered area." It can be understood that the "wireless communication area" formed by nodes 3 that conform to or are based on wireless LAN standards corresponds to the term "cell" in cellular communications. For example, the "wireless communication area" formed by each node 3 can be understood as equivalent to a "femtocell," which is classified as a "small cell."

[0035] Each node 3 can wirelessly communicate with another node 3 when it is within its "wireless communication area." For a node, any node with which it can directly communicate is considered a neighboring node. Multiple nodes 3, for example, form a wireless BH network 9 via wireless backhaul (BH) lines. Wireless backhaul lines wirelessly relay communications between nodes 3. The term "wireless BH network" can also be omitted, and the term "BH network" can be simply referred to as "BH network."

[0036] Node 3 may also be referred to as a base station, AP (Access Point), relay node, or wireless node. Terminal device 7 may also be referred to as a STA (Station). The wireless access line for wireless communication between node 3 and terminal device 7 may also be referred to as an access channel or access network. BH may also be interpreted as "relay." Adjacent may also be interpreted as "adjacent" or "nearby." In these terms, "wireless" may be omitted, and "BH" may be interpreted as "relay."

[0037] In the following description, the term "signal" can be interpreted as a term for a unit of a signal divided by time, such as a "frame" or a "packet."

[0038] Channels available to nodes can be used for both wireless BH lines and wireless access lines. Different frequencies (channels) can be assigned to wireless BH lines and wireless access lines. As a non-limiting example, channels in the 5 GHz band (e.g., 5.15-5.85 GHz) can be assigned to wireless BH lines.

[0039] Channels in the 2.4 GHz band (e.g., 2.412 to 2.472 GHz) can be allocated to the wireless access line. Alternatively, frequencies in the 5 GHz band may be allocated to the wireless access line as long as they are different from those allocated to the wireless BH line.

[0040] The 5 GHz band may include, for example, at least one of a 5.2 GHz band (W52: 5150-5250 MHz), a 5.3 GHz band (W53: 5250-5350 MHz), and a 5.6 GHz band (W56: 5470-5725 MHz).

[0041] The number of channels available for W52 is 4: 36, 40, 44, and 48. The number of channels available for W53 is 4: 52, 56, 60, and 64. The number of channels available for W56 is 12: 100, 104, 108, 112, 116, 120, 124, 128, 132, 136, 140, and 144.

[0042] Therefore, for example, when one or two frequency bands of W52, W53, and W56 are allocated to a wireless access line, the remaining one or two frequency bands of W52, W53, and W56 not allocated to the access line may be allocated to a wireless BH line.

[0043] Node #0 can be called "core node (CN)" or "central base station". Among the multiple nodes 3 constituting the BH network 9, each node 3 except CN #0 can be called "slave node (SN)" or "peripheral base station". For example, Figure 1 In FIG, nodes #1 to #7 are all SNs. CN3 is an example of a "first node", and SN3 is an example of a "second node".

[0044] In addition, Figure 1 In the figure, the numbers #0 to #7 assigned to each node 3 are examples of information used to identify each node 3 (hereinafter sometimes referred to as "node identification information"). Node identification information can be any information that uniquely identifies each node 3 within the same BH network 9. For example, it can be a node number, a device identifier, or address information. A non-limiting example of address information is a MAC (Media Access Control) address.

[0045] The BH network 9 may have a mesh structure (hereinafter sometimes referred to as a "mesh topology" or "mesh network") including one CN 3 (#0). Furthermore, the BH network of the present disclosure is not limited to the mesh topology. For example, the BH network 9 may also have a tree topology with CN #0 as the root node.

[0046] Node 3 can be either a CN or a SN. Whether each node 3 becomes a CN or a SN can be determined based on the quality of the transmission path between nodes, through negotiation between nodes, based on the size of the node identification information, based on whether it is connected to the backbone network, or through other methods.

[0047] <Example of the internal structure of a node>

[0048] Next, use Figure 2 The following describes the internal structure of each node 3. Each node 3 includes a BH line communication unit 201, an access line communication unit 202, a monitoring unit 203, a control unit 204, and a memory 205.

[0049] The BH line communication unit 201 communicates with other nodes 3 on a channel used as a BH line (e.g., channel C). The BH line communication unit 201 communicates with other nodes using the channel specified by the control unit 204. Furthermore, the BH line communication unit 201 receives various messages from other nodes, such as "monitoring channel information," "monitoring channel change requests," and "radar wave detection information," and broadcasts this information to neighboring nodes. Furthermore, the BH line communication unit 201 monitors radar waves on the channel used as the BH line. Hereinafter, the channel used as the BH line may be referred to as the "BH channel."

[0050] The access line communication unit 202 communicates with the terminal device 7 using the channel used as the access line. The access line communication unit 202 communicates with the terminal device 7 using the channel specified by the control unit 204. Specifically, the terminal device 7 and the node 3 communicate using the access line, and the nodes 3 communicate with each other using the backhaul line. The access line communication unit 202 monitors radar waves for the channel used as the access line. The channel used by the access line communication unit 202 as the access line does not need to be the same for all nodes; the channel used as the access line can vary between nodes.

[0051] The monitoring unit 203 monitors (or monitors) the channel designated by the control unit 204 for radar waves. The monitoring unit 203 may monitor multiple channels for radar waves. When radar waves are detected in a channel used as a BH line or a channel used as an access line, the monitoring channel is used as the channel used by the BH line or access line. Therefore, the monitoring channel is set in the same 5 GHz frequency band.

[0052] The BH line communication unit 201, access line communication unit 202, and monitoring unit 203 can monitor for radar waves by, for example, measuring the signal level of a channel. In this case, if a signal level exceeding a predetermined value is detected for a predetermined period of time, the BH line communication unit 201, access line communication unit 202, and monitoring unit 203 determine that a radar wave has been detected. Upon detecting a radar wave, the BH line communication unit 201, access line communication unit 202, and monitoring unit 203 notify the control unit 204 of information indicating this (hereinafter referred to as "radar wave detection information"). Alternatively, if monitoring for radar waves is performed on multiple channels, the monitoring unit 203 may notify the control unit 204 of information indicating the channel in which the radar wave was detected.

[0053] The control unit 204 controls the overall operation of the node 3. The control unit 204 may include a processor. The processor may be, for example, a CPU (central processing unit) or a DSP (digital signal processor).

[0054] The control unit 204 sets the channel used by the BH line communication unit 201 and instructs the BH line communication unit 201. Furthermore, the control unit 204 sets a channel different from the channel used by the BH line communication unit 201 as the channel used by the access line communication unit 202 and instructs the access line communication unit 202. Furthermore, the control unit 204 sets a channel other than the channel used by the BH line communication unit 201 and the channel used by the access line communication unit 202 and instructs the monitoring unit 203.

[0055] Furthermore, the control unit 204 monitors whether the BH line communication unit 201 has received the "radar wave detection information." If the control unit 204 detects that the BH line communication unit 201 has received the "radar wave detection information," the control unit 204 forwards the received "radar wave detection information" from the BH line communication unit 201 to the adjacent node.

[0056] When node 3 operates as a CN, the control unit 204 sets a listening channel and transmits information about the set listening channel (hereinafter referred to as "listening channel information") from the BH line communication unit 201 to neighboring nodes. The control unit 204 monitors whether the BH line communication unit 201 has received a "listening channel change request." If the control unit 204 detects that the BH line communication unit 201 has received a "listening channel change request," it sets a new listening channel and transmits the listening channel information from the BH line communication unit 201 to neighboring nodes.

[0057] When node 3 acts as an SN, the control unit 204 monitors whether the BH line communication unit 201 has received "channel monitoring information" or "channel monitoring change request". When "channel monitoring information" or "channel monitoring change request" is received, the control unit 204 forwards (sends) the received "channel monitoring information" or "channel monitoring change request" from the BH line communication unit 201 to an adjacent node. When the control unit 204 receives "channel monitoring information", it causes the monitoring unit 203 to set the monitored channel included in the received "channel monitoring information".

[0058] When notified by the BH line communication unit 201 of the detection of a radar wave, the control unit 204 interrupts the use of the channel being used in the BH line communication unit 201 and controls the BH line communication unit 201 to communicate using the channel in which the monitoring unit 203 has been monitoring the radar wave in the BH line communication unit 201.

[0059] When notified by the access line communication unit 202 of the detection of a radar wave, the control unit 204 interrupts the use of the channel being used in the access line communication unit 202 and controls the access line communication unit 202 to use a channel other than the channel used in the BH line communication unit 201 and the channel in which the monitoring unit 203 has been monitoring the radar wave in the access line communication unit 202. Alternatively, the control unit 204 may control the access line communication unit 202 to use the channel in which the monitoring unit 203 has been monitoring the radar wave in the access line communication unit 202 and change the channel in which the monitoring unit 203 monitors the radar wave to another channel.

[0060] It is possible that when the control unit 204 receives a notification of the detection of a radar wave from the monitoring unit 203, it changes the channel in which the monitoring unit 203 monitors the radar wave to another channel. When the monitoring unit 203 monitors the radar wave for multiple channels, the control unit 204 may change the channel in which the radar wave is detected to another channel or may change all channels.

[0061] The memory 205 stores programs of an OS (operating system), application programs, and various data required for processing by the processor. The memory may be, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), a flash memory, an SSD (solid state drive), and / or an HDD (hard disk drive).

[0062] <Action of CN>

[0063] Next, use Figure 3 The flowchart of illustrates the operation of CN.

[0064] The CN and the SN start communicating together on the BH line (S301).

[0065] The CN sets a new channel, that is, a channel to be switched to when radar waves are detected in the channel currently being used for BH communication during BH communication, as a monitoring channel (S302). The monitoring channel is selected from available channels and can be set based on the channel congestion or randomly. Based on the historical records of radar wave detections in the CN and SN, channels with a low frequency or number of radar wave detections can be set as monitoring channels, thereby setting channels with a high probability of not detecting radar waves as monitoring channels. The monitoring channel can also be set taking into account the time when the radar wave was detected and the current time. According to laws and regulations, a channel where radar waves were detected cannot be used within 30 minutes after the detection of the radar wave. Therefore, it is possible not to set a channel where radar waves were detected in the past 30 minutes as a monitoring channel. In addition, multiple monitoring channels can be set.

[0066] In the CN, the monitoring unit starts monitoring the set channel (S303).

[0067] The CN transmits information indicating the channel on which monitoring has started as "monitoring channel information" to neighboring nodes via the BH line (S304). The monitoring channel information can be transmitted by broadcast. If multiple monitoring channels are set in S302, multiple monitoring channel information may be transmitted, each of which includes information indicating one of the multiple monitoring channels, or a single monitoring channel information may be transmitted, including information indicating multiple monitoring channels.

[0068] The CN determines whether a radar wave is detected in the monitoring channel (S305).

[0069] If the CN detects radar waves in S305 (Yes), the process returns to the monitoring channel setting in S302, and the CN re-sets another monitoring channel. If multiple monitoring channels are set in S302, the monitoring channel change request may include information for identifying the monitoring channel for which the change request is made.

[0070] When no radar wave is detected in S305 (No), the CN determines whether a monitoring channel change request is received ( S306 ).

[0071] When the CN receives a monitoring channel change request in S306 (yes), the process returns to the monitoring channel setting in S302, and the CN re-sets other monitoring channels. When multiple monitoring channels are set, the monitoring channel change request may include information for identifying the monitoring channel targeted by the change request.

[0072] When the CN does not receive a monitoring channel change request in S306 (no), the CN determines whether a radar wave is detected in the channel used by the BH line (S307).

[0073] When a radar wave is detected in S307 (yes), the CN sends the fact that a radar wave has been detected in the BH channel (hereinafter referred to as "radar wave detection information") to adjacent nodes via the BH line (S308). The radar wave detection information can be sent via broadcast. Since communication using the BH channel where the radar wave is detected needs to be interrupted within 10 seconds, in order to send the radar wave detection information on the BH line, it is necessary to send the radar wave detection information before interrupting the communication using the BH channel.

[0074] When a radar wave is not detected in S307 (no), the CN determines whether it has received radar wave detection information (S309).

[0075]

[0076] When the CN does not receive radar wave detection information in S309 (no), the process returns to S305, and the CN determines whether a radar wave is detected in the monitoring channel.

[0077] After the CN sends the radar wave detection information to adjacent nodes in S308, or after forwarding (sending) the radar wave detection information to adjacent nodes in S310, it changes the channel used by the BH line from the current channel to the monitoring channel (S311). When multiple monitoring channels are being monitored, which monitoring channel to change to is determined according to specified conditions. The determined channel can be the channel with the longest time without detecting a radar wave, or the channel with the smallest identification number.

[0078] The order of S303 and S304 can be swapped. In addition, the order of S305, S306, S307, and S309 can also be swapped. Also, in S311, when the monitoring time of the monitoring channel is less than 1 minute, the channel used by the BH line can also be changed to the monitoring channel after 1 minute.

[0079] <Actions of the SN>​

[0080] Next, use Figure 4 The flowchart of SN illustrates the operation of SN.

[0081] The SN starts communicating with the CN and other SNs on the BH line (S401).

[0082] The SN determines whether it has received monitoring channel information from a neighboring node (S402).

[0083] In the case that the SN does not receive the monitoring channel information from the neighboring node in S402 (No), the process returns to S402, and the SN determines again whether the monitoring channel information is received.

[0084] When the monitoring channel information is received from the neighboring node in S402 (Yes), the SN checks whether radar waves have been detected in the past 30 minutes in the monitoring channel included in the monitoring channel information ( S403 ).

[0085] The channel that node 3 can use can be any of the channels used by the BH line, the channels used by the access line, and the monitoring channel. When a radar wave is detected in the monitoring channel or in the channel used by the BH line, "radar wave detection information" is sent or forwarded to the adjacent node via the BH channel, and the CN eventually receives the radar wave detection information. Therefore, the channel that detected radar waves in the past 30 minutes is Figure 3 The channel will not be set as a listening channel in the listening channel setting performed by the CN as described in S302, so the channel will not be notified in the listening channel information received by the SN. However, when radar waves are detected in the channel used by the access line, since the radar wave detection information is not sent to the adjacent nodes, the CN is unaware that the SN has detected radar waves in the channel used by the access line. Therefore, since the channel used as an access line in the SN and where radar waves were detected may be set as a listening channel in the listening channel setting of S302, the processing of S403 is required. If the SN, when detecting radar waves in the channel used as an access line, sends "access line radar wave detection information" to the adjacent nodes via the BH channel indicating that radar waves have been detected in the channel used as the access line, and forwards the "access line radar wave detection information" to the adjacent nodes upon receiving the "access line radar wave detection information", the CN can perform the listening channel setting taking into account the fact that radar waves have been detected in the channel used by the SN as the access line, and therefore the processing of S403 is not required.

[0086] If the result in S403 indicates that radar waves have been detected within the past 30 minutes (Yes), the SN sends a monitoring channel change request to the neighboring node via the BH line (S407). The monitoring channel change request can be sent by broadcast. If multiple monitoring channels are received, the monitoring channel change request can also include information for identifying the monitoring channel where the radar waves were detected.

[0087] If the result of S403 is that no radar wave has been detected in the past 30 minutes (No), the SN starts monitoring the monitoring channel in the monitoring unit 203 (S404).

[0088] The SN forwards (sends) the channel it starts monitoring as monitoring channel information to the adjacent nodes via the BH line (S405). The monitoring channel information can be forwarded by broadcasting.

[0089] The SN determines whether radar waves are detected in the monitoring channel (S406).

[0090] If radar waves are detected on the monitoring channel in S406 (Yes), the SN sends a monitoring channel change request to the neighboring node via the BH line (S407). The monitoring channel change request can be sent by broadcast. After the SN sends the monitoring channel change request via the BH line in S407, the process returns to S402, and the SN determines whether the monitoring channel information has been received.

[0091] When no radar wave is detected in the monitoring channel in S406 (No), the SN determines whether a monitoring channel change request is received (S408).

[0092] If a monitoring channel change request is received in S408 (Yes), the SN forwards (sends) the monitoring channel change request to the neighboring node via the BH line (S409). The monitoring channel change request can be forwarded by broadcast. After the SN sends the monitoring channel change request via the BH line in S409, the process returns to S402, and the SN again determines whether the monitoring channel information has been received.

[0093] When no monitoring channel change request is received in S408 (No), the SN determines whether radar waves are detected in the channel used by the BH line (S410).

[0094] If radar waves are detected in S410 (Yes), the SN transmits radar wave detection information to neighboring nodes via the BH line (S411). Radar wave detection information can be transmitted by broadcast. The channel used by the BH line that detects radar waves must interrupt communication within 10 seconds. Therefore, in order to transmit radar wave detection information on the BH line, it is necessary to transmit the radar wave detection information before interrupting communication using the BH channel.

[0095] When no radar wave is detected in S410 (No), the SN determines whether radar wave detection information is received (S412).

[0096] If the radar wave detection information is received in S412 (Yes), the SN forwards (sends) the radar wave detection information to the adjacent node via the BH line (S413). The radar wave detection information may be forwarded by broadcasting.

[0097] In the case that the SN does not receive the radar wave detection information in S412 (No), the process returns to S406, and the SN determines whether the radar wave is detected in the monitoring channel.

[0098] After the SN sends the radar wave detection information to the neighboring node in S411, or after forwarding the radar wave detection information to the neighboring node in S413, the channel used by the BH line is changed from the current channel to the listening channel (S414). When multiple listening channels are being monitored, the listening channel to be changed to is determined based on specified conditions. The determined channel can be the channel with the longest period of no radar wave detection or the channel with the smallest identification number. After the SN changes the channel used by the BH line from the current channel to the listening channel in S414, the process returns to S402, and the SN again determines whether the listening channel information has been received.

[0099] The order of S403, S404, and S405 can be reversed. Furthermore, the order of S406, S408, S410, and S412 can also be reversed. Furthermore, in S414, if the monitoring time of the monitoring channel is less than 1 minute, the channel used in the BH line can be changed to the monitoring channel after 1 minute has passed.

[0100] <Actions of each node>

[0101] Figure 5 An example of a sequence diagram showing the actions of CN#0, SN#1, and SN#4 is shown. These nodes constitute Figure 1 A node among the nodes of the wireless communication system shown. CN#0 performs Figure 3 The recorded action, SN#1 and SN#4 performed Figure 4 The described operation. CN#0 and SN#1 are adjacent nodes, SN#1 and SN#4 are adjacent nodes, but CN#0 and SN#4 are not adjacent nodes. In other words, CN#0 and SN#4 can communicate through SN#1 as a relay.

[0102] The following example operation is described: when channel C is used by the BH line, channel A is set as the monitoring channel. However, since radar waves are detected on channel A in SN#1, the monitoring channel is changed to channel B. When radar waves are detected on channel C, the channel is changed to channel B.

[0103] CN#0 sets a monitoring channel (eg, channel A) (S501).

[0104] In CN#0, the monitoring unit 203 monitors the radar waves on the set monitoring channel (for example, channel A) (S502).

[0105] CN#0 transmits the set listening channel (for example, channel A) as "listening channel information" to the neighboring nodes (S503). The transmission can be performed by broadcasting.

[0106] SN#1, which is a neighboring node of CN#0, receives the "monitoring channel information".

[0107] SN#1 checks whether radar waves have been detected in the past 30 minutes on the monitoring channel (e.g., channel A) indicated in the received "monitoring channel information" (S504). Since 30 minutes is a time period determined by laws and regulations, it can also be changed as laws and regulations change.

[0108] Assume that in SN#1, radar waves have been detected in the listening channel (e.g., channel A) indicated by the "Listening Channel Information (e.g., channel A)" within the past 30 minutes. In other words, in SN#1, radar waves have been detected in channel A, which is used as an access line, within the past 30 minutes. At this time, SN#1 sends a "Listening Channel Change Request" (S505) to the neighboring node to request CN#0 to change the set listening channel. The "Listening Channel Change Request (e.g., Channel A Change Request)" sent in S505 can be identified as the "Listening Channel Change Request (e.g., Channel A Change Request)" related to the "Listening Channel Information (e.g., Channel A)" sent in S503.

[0109] Upon receiving the "monitoring channel change request (e.g., a request to change channel A)", CN#0 performs monitoring channel configuration and sets a new monitoring channel (e.g., channel B) (S506). SN#4 also receives the "monitoring channel change request (e.g., a request to change channel A)" sent by SN#1. However, since SN#4 has not received the "monitoring channel information (e.g., channel A)" associated with the received "monitoring channel change request (e.g., a request to change channel A)", it ignores the received "monitoring channel change request (e.g., a request to change channel A)".

[0110] In CN#0, the monitoring unit starts monitoring the newly set monitoring channel (for example, channel B) (S507).

[0111] CN#0 transmits the newly configured "monitoring channel information (e.g., channel B)" to neighboring nodes (S508). The monitoring channel information can be broadcast. Sequence numbers, etc., can be used to identify the monitoring channel information transmitted in S508 as "monitoring channel information (e.g., channel B)" different from the "monitoring channel information (e.g., channel A)" transmitted in S503.

[0112] SN #1 checks whether radar waves have been detected on the monitoring channel (e.g., channel B) indicated by "Monitoring Channel Information (e.g., channel B)" within the past 30 minutes (S509). Since 30 minutes is a time period determined by laws and regulations, it can be changed as laws and regulations change.

[0113] Assume that SN#1 has not detected radar waves on the monitoring channel (e.g., channel B) indicated by "Monitoring Channel Information (e.g., channel B)" within the past 30 minutes. In this case, SN#1 begins monitoring the monitoring channel (e.g., channel B) indicated by the notified "Monitoring Channel Information (e.g., channel B)" (S510). SN#1 may also notify CN#0, which has transmitted the monitoring channel information, that no radar waves have been detected within the past 30 minutes.

[0114] SN#1 forwards the "monitored channel information (e.g., channel B)" to the adjacent node (S511). The "monitored channel information (e.g., channel B)" forwarded in S511 can be identified as a forwarding of the "monitored channel information (e.g., channel B)" sent in S508 by using a sequence number, etc.

[0115] SN#4, a neighboring node of SN#1, receives the "monitoring channel information (e.g., channel B)." CN#0 also receives the "monitoring channel information (e.g., channel B)" forwarded in S511, but because it is a forwarding of the "monitoring channel information (e.g., channel B)" sent by CN#0 itself, CN#0 ignores the received "monitoring channel information (e.g., channel B)."

[0116] SN #4 checks whether radar waves have been detected on the monitoring channel (e.g., channel B) indicated by "Monitoring Channel Information (e.g., channel B)" within the past 30 minutes (S512). Since 30 minutes is a time period determined by laws and regulations, it can be changed as laws and regulations change.

[0117] Assume that in SN #4, no radar waves have been detected on the monitoring channel (e.g., channel B) indicated by "Monitoring channel information (e.g., channel B)" within the past 30 minutes. In this case, monitoring is started on the monitoring channel (e.g., channel B) notified by "Monitoring channel information (e.g., channel B)" (S513).

[0118] SN#4 detects radar waves on the BH channel (eg, channel C) (S514).

[0119] In order to notify the nodes constituting the BH communication network that radar waves have been detected on the BH channel (e.g., channel C), SN#4 sends "radar wave detection information" to the adjacent nodes (S515) and changes the BH channel used by the BH line from the currently used channel (e.g., channel C) to the monitoring channel (e.g., channel B) (S516).

[0120] SN#1 receives the "radar wave detection information," forwards it (S517), and changes the BH channel used by the BH line from the currently used channel (e.g., channel C) to the monitoring channel (e.g., channel B) (S518). The sequence number, etc., allows identification that the "radar wave detection information" forwarded in S517 is a forwarding of the "radar wave detection information" sent in S515.

[0121] CN#0 receives the "radar wave detection information," forwards it, and changes the BH channel used by the BH line from the currently used channel (e.g., channel C) to the monitoring channel (e.g., channel B) (S519). SN#4 also receives the "radar wave detection information" sent by SN#1 in S517, but because it is a forwarding of the "radar wave detection information" sent by SN#4 itself, SN#4 ignores the received "radar wave detection information." Furthermore, CN#0 forwards the "radar wave detection information" received in S517 to its neighboring nodes, but to SN#1, it is a forwarding of the "radar wave detection information" it has already forwarded, so SN#1 ignores the received "radar wave detection information."

[0122] about Figure 5 The same applies to SN not recorded in .

[0123] <Summary of Implementation Methods>

[0124] As described above, all nodes 3 constituting the wireless backhaul system use channel C as the BH channel and channel B as the monitoring channel. Therefore, when a node 3 (e.g., SN#4) detects radar waves on channel C, each node 3 interrupts use of channel C, currently serving as the BH channel, and uses the monitoring channel, channel B. Consequently, all nodes 3 constituting the wireless backhaul communication system use the monitoring channel, channel B, as the BH channel. In other words, all nodes monitor the same monitoring channel. If radar waves are detected by any of the nodes 3 constituting the wireless backhaul system, all nodes 3 switch the channel used as the backhaul line to the same monitoring channel, thereby achieving high-speed DFS in the wireless backhaul communication system.

[0125] <Modification>

[0126] The monitoring unit may monitor a plurality of channels. In the case of monitoring a plurality of channels, the channel where the radar wave is detected may be included in the "monitoring channel change request".

[0127] Regarding the channel used in the access line communication unit (e.g., channel D), when radar waves are detected, the node may use the monitoring channel (e.g., channel A) monitored by the monitoring unit in the access line communication unit, and may set the monitoring channel or send a monitoring channel change request to change the monitoring channel. Alternatively, an "access line monitoring unit" for performing high-speed DFS on the access line may be provided in each node, and the channel used by the access line may be changed from the currently used channel (e.g., channel D) to the access line monitoring channel (e.g., channel E) monitored by the access line monitoring unit. The channel monitored by the access line monitoring unit may be any channel other than the channel used in the BH line communication unit (e.g., channel C), the channel used in the access line communication unit (e.g., channel D), or the channel monitored by the monitoring unit (e.g., channel A) (e.g., channel E).

[0128] Alternatively, the channel used by the access line communication unit may be notified to neighboring nodes as "access line channel information," and the received "access line channel information" may be notified to neighboring nodes, thereby notifying the CN of the channel used by the SN in the access line communication unit. Alternatively, a "monitoring channel change request" may be sent when the "monitoring channel information" indicates the channel currently being used by the access line communication unit.

[0129] When the channel notified in the "monitoring channel information" is the channel used by the SN as an access line, a "monitoring channel change request" may be sent, and the channel used as the access line may be changed.

[0130] Node 3 may also include a 5G (fifth generation mobile phone) access point module. The channel monitored by the monitoring unit (e.g., channel A) may be used as the channel to change to when radar waves are detected by the 5G access point module. A "5G monitoring unit" may be provided in a node equipped with a 5G access point module and configured to perform monitoring similar to the access line monitoring unit.

[0131] In cases where radar waves are detected during a specific time period, the channel used for BH communication may be changed based on the time. The channel used for BH communication after the specified time may be monitored before the specified time.

[0132] When the BH line communication unit no longer receives BH communication, it may be determined that the BH channel has been switched or a failure has occurred in the BH channel and other channels may be scanned in sequence. The monitoring channel may be set as the channel to be scanned first.

[0133] (1) In one embodiment of the present disclosure, a node used in a wireless backhaul system includes: an access line communication unit that communicates with a terminal device using a first channel; a backhaul line communication unit that communicates with an adjacent node using a second channel and sends monitoring channel information indicating a third channel to the adjacent node; and a monitoring unit that monitors radar waves on the third channel.

[0134] (2) A node used in a wireless backhaul system according to one embodiment of the present disclosure is the node described in (1), further comprising a control unit for setting the third channel.

[0135] (3) In a node used in a wireless backhaul system according to an embodiment of the present disclosure, in the node described in (2), the control unit sets the third channel based on past history records.

[0136] (4) In a node used in a wireless backhaul system according to an embodiment of the present disclosure, in the node described in (1), the backhaul line communication unit forwards the listening channel information to the adjacent node upon receiving the listening channel information from the adjacent node.

[0137] (5) A node used in a wireless backhaul system according to an embodiment of the present disclosure is a node described in (4), further comprising a control unit that confirms whether a radar wave has been detected within a specified time period in the past on the third channel indicated by the received monitoring channel information.

[0138] (6) In a node used in a wireless backhaul system according to an embodiment of the present disclosure, in any one of (1) to (4), the sending or forwarding of the monitoring channel information is performed by broadcasting.

[0139] (7) A node used in a wireless backhaul system according to an embodiment of the present disclosure is a node described in (1), further comprising a control unit. When the backhaul line communication unit detects a radar wave or receives information indicating that a radar wave has been detected, the control unit causes the backhaul line communication unit to send information indicating that a radar wave has been detected to the adjacent node, and causes the backhaul line communication unit to change a channel to use the third channel.

[0140] (8) A wireless backhaul communication system according to an embodiment of the present disclosure includes a first node and a second node, wherein the first node includes: a first access line communication unit for communicating with a terminal device using a first channel; a first backhaul line communication unit for communicating with an adjacent node using a second channel; a first monitoring unit for monitoring radar waves on a third channel; and a first control unit for setting the third channel and causing the first backhaul line communication unit to send monitoring channel information indicating the third channel to the adjacent node, and the second node includes: a second access line communication unit for communicating with a terminal device using a fourth channel; a second backhaul line communication unit for communicating with an adjacent node using the second channel; a second monitoring unit for monitoring radar waves on the third channel; and a second control unit for causing the second backhaul line communication unit to forward the monitoring channel information indicating the third channel to the adjacent node when the second backhaul line communication unit receives the monitoring channel information.

[0141] (9) A wireless backhaul communication system according to an embodiment of the present disclosure is composed of a plurality of nodes that communicate with each other using a common channel, wherein each node comprises: a communication unit that communicates with an adjacent node using a specific common channel; a monitoring unit that monitors a monitoring channel that is different from the common channel in use; and a control unit that, when a radar wave is detected on the common channel being used by the communication unit, changes the channel so that the monitoring channel becomes the channel used by the communication unit, and causes the communication unit to send information to the adjacent node indicating that a radar wave is detected on the common channel in use.

[0142] (10) A wireless backhaul communication system according to an embodiment of the present disclosure is a wireless backhaul communication system according to (9), wherein a case where radar waves are detected in a common channel being used by the communication unit refers to a case where radar waves are detected in the communication unit or information indicating that radar waves are detected is received from an adjacent node.

[0143] (11) In a method of one embodiment of the present disclosure, each node of a wireless backhaul communication system composed of multiple nodes communicating with each other using a common channel performs the following steps: a step of sending monitoring channel information indicating a monitoring channel different from the common channel in use to an adjacent node; and a step of monitoring the monitoring channel.

[0144] (12) A method of an embodiment of the present disclosure is, in the method described in (11), further comprising the following steps: when a radar wave is detected on the public channel in use, or when information indicating that a radar wave is detected on the public channel in use is received from an adjacent node, the step of sending information indicating that a radar wave is detected on the public channel in use to the adjacent node; and the step of performing a channel change to communicate with the adjacent node using the monitoring channel.

[0145] (13) A program according to an embodiment of the present disclosure causes a processor of a node to execute the method described in (11) or (12).

[0146] (14) A node used in a wireless backhaul system according to an embodiment of the present disclosure includes: a backhaul line communication unit that communicates with an adjacent node using a first channel and sends monitoring channel information indicating a second channel to the adjacent node; and a monitoring unit that monitors radar waves on the second channel.

[0147] The disclosures of the specification, drawings, and abstract of Japanese patent application No. 2023-004570 filed on January 16, 2023 are incorporated herein by reference in their entirety.

[0148] Industrial Applicability

[0149] The present disclosure is useful for wireless backhaul systems for wireless mesh networks and the like.

[0150] Description of Reference Numerals

[0151] 1: Wireless communication system

[0152] 3: Node

[0153] 7: Terminal device

[0154] 9: BH Network

[0155] 201: BH Line Communication Department

[0156] 202: Access Line Communications Department

[0157] 203: Monitoring Department

[0158] 204: Control Department

[0159] 205: Memory

Claims

1. A node used in a wireless backhaul system, comprising: an access line communication unit for communicating with the terminal device using a first channel; a backhaul line communication unit that communicates with a neighboring node using the second channel and sends monitoring channel information indicating a third channel to the neighboring node; and The monitoring unit monitors the radar waves on the third channel.

2. The node according to claim 1, wherein: The device further includes a control unit for setting the third channel.

3. The node according to claim 2, wherein: The control unit sets the third channel based on past history.

4. The node according to claim 1, wherein: Upon receiving the monitoring channel information from a neighboring node, the backhaul line communication unit forwards the monitoring channel information to the neighboring node.

5. The node according to claim 4, wherein: The system further includes a control unit configured to confirm whether a radar wave has been detected within a predetermined time period in the past on the third channel indicated by the received monitoring channel information.

6. The node according to claim 1, wherein: The sending or forwarding of the monitoring channel information is performed through broadcasting.

7. The node according to claim 1, wherein: The backhaul line communication unit further includes a control unit. When the backhaul line communication unit detects a radar wave or receives information indicating that a radar wave has been detected, the control unit causes the backhaul line communication unit to transmit information indicating that a radar wave has been detected to the adjacent node, and causes the backhaul line communication unit to change a channel to use the third channel.

8. A wireless backhaul communication system, wherein: Having a first node and a second node, The first node has: a first access line communication unit for communicating with the terminal device using a first channel; a first backhaul line communication unit, communicating with an adjacent node using a second channel; The first monitoring unit monitors radar waves on the third channel; as well as The first control unit sets the third channel and causes the first backhaul line communication unit to transmit monitoring channel information indicating the third channel to the adjacent node. The second node has: a second access line communication unit for communicating with the terminal device using a fourth channel; a second backhaul line communication unit, configured to communicate with adjacent nodes using the second channel; a second monitoring unit, monitoring radar waves on the third channel; as well as The second control unit causes the second backhaul line communication unit to forward the listening channel information indicating the third channel to the adjacent node when the second backhaul line communication unit receives the listening channel information.

9. A wireless backhaul communication system comprising a plurality of nodes communicating with each other using a common channel, wherein: Each node has: Communication unit, which uses a specific public channel to communicate with adjacent nodes; a monitoring unit that monitors a monitoring channel different from a common channel in use; and The control unit, when radar waves are detected in the common channel being used by the communication unit, changes the channel so that the monitoring channel becomes the channel used by the communication unit, and causes the communication unit to send information indicating that radar waves are detected in the common channel being used to the adjacent node.

10. The wireless backhaul communication system according to claim 9, wherein: The case where radar waves are detected in the common channel being used by the communication unit refers to the case where radar waves are detected by the communication unit or information indicating that radar waves are detected is received from a neighboring node.

11. A method wherein: Each node of a wireless backhaul communication system composed of multiple nodes communicating with each other using a common channel performs the following steps: a step of transmitting, to a neighboring node, monitoring channel information indicating a monitoring channel different from a common channel in use; and The step of monitoring the monitoring channel.

12. The method of claim 11, wherein: The following steps are also included: When a radar wave is detected on the common channel in use, or when information indicating that a radar wave is detected on the common channel in use is received from a neighboring node, the step of transmitting information indicating that a radar wave is detected on the common channel in use to the neighboring node; as well as The step of performing a channel change to communicate with a neighboring node using the listening channel.

13. A program causing a processor of a node to execute the method according to claim 11.

14. A node used in a wireless backhaul system, the node comprising: a backhaul line communication unit that communicates with a neighboring node using the first channel and sends monitoring channel information indicating the second channel to the neighboring node; and The monitoring unit monitors the radar waves on the second channel.

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