JP2011223158A - Radio system, radio terminal, and method and program of radio communication - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique for preventing a terminal in a mesh network from losing a communication path in the event of no channel change notification received from other terminals in the mesh network.SOLUTION: A radio terminal in a mesh network sends a notification about channel change which takes place on the terminal to other radio terminals within the network. Individual terminals which receive the notification determine whether to switch channels based on the notification.

Description

  The present invention relates to a wireless system, a wireless terminal, a wireless communication method, and a program.

  A new standard for realizing a mesh network using IEEE802.11 wireless LAN is discussed as TGs (for example, Non-Patent Document 1). This is a technique different from communication between an access point and a client as is performed in a normal wireless LAN. A terminal establishes a link connection with an adjacent terminal, and data communication to a terminal that does not communicate directly on the same mesh network, that is, a terminal that is not an adjacent terminal, is performed by a terminal on the same mesh network. I will forward it.

  In TGs, standardization work is in progress regarding the method of establishing a link connection between adjacent terminals, security, power saving, and the like. Among them, specifications are also defined for channel change methods when interference from other wireless systems is detected (for example, Non-Patent Document 2). In this channel change method, first, a terminal that detects interference from another wireless system transmits a channel change notification to another adjacent terminal. The channel change notification includes a reason for change, a new channel, a change timing, and the like. The terminal that has received this channel change notification determines whether or not to change the channel based on the channel change notification, and when changing the channel, transmits the channel change notification to the adjacent terminal. Thus, when there is interference from another wireless system, the terminal that detected the interference transmits the information to the adjacent terminal and moves to another channel.

IEEE Std 802.11-2007 IEEE Std 802.11s-Draft 3.0

  However, in response to this channel change notification, whether or not to change the channel in accordance with the notification is determined by each terminal, and is not defined in the specification. Even in the case of a terminal that has received a channel change notification, if the channel is not changed according to the channel change notification, there is no provision for transmission of a channel change notification to a further adjacent terminal. Therefore, in a case where the channel is not changed and the channel change notification is not transmitted to the adjacent terminal, the adjacent terminal may suddenly lose communication with other non-adjacent terminals.

  In addition, in the case where the channel change is not performed and the channel change notification is transmitted to the adjacent terminal, the adjacent terminal changes the channel along the channel change notification to perform the direct communication. The link with the terminal may be lost, and communication with other terminals may become impossible. Therefore, even when a channel change notification is received, how to determine channel change is very difficult.

  As described above, in the current specification, it is difficult to use the channel change notification, and there is a possibility that the data communication path may be suddenly lost without any notification to the terminal.

  An object of the present invention is to solve the above-described problems, and to provide a technique that does not lose a communication path in a mesh network without a notification of channel change from another terminal.

  The present invention that solves the above-described problems is a wireless system, and is characterized by notifying a wireless terminal on the same mesh network of information regarding a channel change performed by the terminal on the network.

  The present invention that solves the above-described problem is a wireless terminal that generates information on a channel change performed by a terminal on the network and notifies an adjacent wireless terminal of the wireless terminal on the same mesh network. It is characterized by having.

  The present invention for solving the above-mentioned problems is a wireless communication method, characterized in that information on channel change performed by a terminal on the network is notified to a wireless terminal on the same mesh network.

  The present invention that solves the above-described problem is a program for a wireless terminal, and the program generates information related to channel changes performed by a terminal on the network to the wireless terminal on the same mesh network. And functioning as a notification means for notifying adjacent wireless terminals.

  According to the present invention, it can be expected that a channel change occurs in some terminals on the network and the link is lost.

FIG. 1 is a schematic diagram of a communication system according to the present invention. FIG. 2 is a block diagram illustrating an example of a wireless communication terminal according to the first embodiment of this invention. FIG. 3 is a diagram for explaining the change notification format. FIG. 4 is a diagram for explaining a channel change notification format according to the present invention. FIG. 5 is a diagram for explaining the operation of the present invention. FIG. 6 is a block diagram illustrating an example of a wireless communication terminal according to the second embodiment of this invention. FIG. 7 is a diagram for explaining a channel change notification format according to the present invention. FIG. 8 is a diagram for explaining the operation of the present invention.

  First, the outline of the present invention will be described. In the present invention, a new item is provided in the channel change notification and Mesh Channel Switch Announcement element defined in IEEE802.11 TGs as shown in FIG. Then, the wireless communication terminal on the same mesh network is notified by inserting information on the channel change performed by the wireless communication terminal on the same network into the newly provided item.

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

(First embodiment)
A first embodiment for carrying out the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a schematic diagram of a wireless communication system according to the present invention. The wireless communication system of the present invention has a plurality of wireless communication terminals. Each wireless communication terminal wirelessly communicates with an adjacent wireless communication terminal using a mesh network technology defined by IEEE802.11 TGs. In the following description, the wireless communication system will be described using a configuration in which six wireless communication terminals 311 to 316 are connected on the same mesh network, but the number of wireless communication terminals is not limited. good.

  FIG. 2 shows the configuration of the wireless communication terminal in the present application. The wireless communication terminal 1 includes an interference detection unit 11, a channel change notification generation unit 12, a wireless communication unit 13 that transmits and receives a channel change notification, and a channel selection determination unit 14.

  The interference detection unit 11 detects interference from other wireless systems. For example, the usage status of a system that uses the same frequency as that of the own terminal, such as a radar or a microwave oven in the house, is detected to detect whether the communication of the own terminal is affected. In addition to the interference, it detects whether the channel used by the terminal itself for wireless communication needs to be changed. Then, based on the detection result, it is determined whether to change the channel, and the channel change notification generation unit 12 is notified of the determination result and the detected content.

  The channel change notification generation unit 12 generates a channel change notification based on the content of the detection result received when the interference detection unit 11 detects the use of the same channel by another system. Here, the details of the channel change notification will be described.

  FIG. 3 shows the format of a channel change notification and Mesh Channel Switch Announcement element defined in IEEE802.11 TGs. Normally, information for identifying a terminal that has detected interference, information on an interference type indicating whether the interference is radar, information on a channel to be changed, and timing for changing are written along this format. As shown in FIG. 4, the channel change notification generated by the channel change notification generation unit 12 according to the present invention is reserved in the Channel Switch Mode (B0 to B7) of the Mesh Channel Switch Announcement element defined by IEEE802.11 TGs. A new item Switch Decision 51 is created in B3 of B3 to B7), and becomes Reserved (B4 to B7). This Switch Decision 51 describes the channel change determination result in the terminal itself. The channel change notification generator 12 inserts “1” when the interference detector 11 detects interference and determines to change the channel, and inserts “0” when it is determined not to change the channel. If it is determined that the channel is to be changed, the reason for the channel change is inserted into Reason in a format that conforms to the regulations. Further, when the channel change notification is received from another terminal, not when the own terminal detects interference, a channel change notification is generated including the channel change determination result of the own station by the channel selection determining unit 14. . In the present invention, items other than Switch Decision 51 are based on the Mesh Channel Switch Announcement element defined in IEEE802.11 TGs, and thus detailed description thereof is omitted.

  The wireless communication unit 13 has a function of communicating with other wireless communication devices using wireless communication. In this embodiment, for example, an IEEE802.11 transceiver is used. The wireless communication unit 13 of the wireless communication terminal that has detected the interference transmits a channel change notification to all adjacent wireless communication terminals. The wireless communication unit 13 of the wireless communication terminal that has received the channel change notification from the adjacent wireless communication terminal changes the channel of the own terminal in addition to the wireless communication terminal that has transmitted the channel change notification used to determine the channel change of the own terminal. Send the indicated channel change notification. The wireless communication unit 13 of the wireless communication terminal that has received the channel change notification from the adjacent wireless communication terminal transmits a channel change notification indicating the channel change of the own terminal to all adjacent wireless communication terminals. Also good.

  When the channel selection determination unit 14 receives the channel change notification, the channel selection determination unit 14 uses at least the information of the switch decision 51 that indicates the determination result of the adjacent wireless communication terminal 312 described in the channel change notification, and changes the channel of the own terminal. Judging whether or not is necessary. The channel selection determination unit 14 further determines the necessity of channel change of the own terminal by further combining the detection result in the interference detection unit 31 of the own terminal and the reason for change described in the Reason of the channel change notification. May be. Further, the channel change notification used for the determination may be the channel change notification received for a certain period or the channel change notification received first, and may be determined every time the channel change notification is received. .

  Next, the operation of the embodiment of the present invention will be described with reference to the flowchart of FIG. In the following description, the case where the wireless communication terminal 311 detects interference will be described.

  When the interference detection unit 11 of the wireless communication terminal 311 detects interference (step S1), it is determined whether or not to change the channel (step S2). If the channel is not changed, the process returns to step S1. On the other hand, when the channel is changed, the channel change notification generator 12 generates a channel change notification (step S3). The wireless communication unit 13 transmits the generated channel change notification to the adjacent wireless communication terminal 312 and wireless communication terminal 313 (step S4).

  When the wireless communication unit 13 of the wireless communication terminal 312 and the wireless communication terminal 313 receives the channel change notification from the wireless communication terminal 311, the channel selection determination unit 14 uses the content of the received channel change notification. It is determined whether or not to change the current channel (step S5).

  Below, it demonstrates using an Example. First, a case where the wireless communication terminal 312 and the wireless communication terminal 313 receive a channel change notification from the wireless communication terminal 311 and determines that neither the wireless communication terminal 312 nor the wireless communication terminal 313 changes the channel will be described.

  The wireless communication terminal 314 determines whether or not to change the channel based on the channel change information described in the switch decision 51 of the channel change notification received from the wireless communication terminal 312 and the wireless communication terminal 313. Here, since Switch Decision 51 is 0 for both the wireless communication terminal 312 and the wireless communication terminal 313, it is determined not to change the channel in order to prioritize maintaining the connection with these adjacent terminals. Then, a new channel change notification is generated based on the determination result, and the generated channel change notification is transmitted to the adjacent wireless terminal 316.

  Subsequently, the wireless communication terminal 312 and the wireless communication terminal 313 receive the channel change notification from the wireless communication terminal 311, determines that the wireless communication terminal 312 changes the channel, and determines that the wireless communication terminal 313 does not change the channel. The case will be described.

  The wireless communication terminal 314 determines whether or not to change the channel based on the channel change information described in the switch decision 51 of the channel change notification received from the wireless communication terminal 312 and the wireless communication terminal 313. In order to change the channel, the wireless communication terminal 312 determines whether or not to change the channel based on the channel change reason described in the Reason of the received channel change notification. Here, it is assumed that the switch decision 51 of the wireless communication terminal 312 is 1, and it is determined that the channel should be changed for the reason of channel change described in Reason. Then, based on the determination result, a new channel change notification for changing the channel is generated and transmitted to the adjacent wireless terminals 316 and 313.

  Next, a case will be described where the wireless communication terminal 312 and the wireless communication terminal 313 receive a channel change notification from the wireless communication terminal 311 and determine that both the wireless communication terminal 312 and the wireless communication terminal 313 change the channel.

  The wireless communication terminal 314 determines whether or not to change the channel based on the channel change information described in the switch decision 51 of the channel change notification received from the wireless communication terminal 312 and the wireless communication terminal 313. Here, since Switch Decision 51 is 1 for both the wireless communication terminal 312 and the wireless communication terminal 313, it is determined to change the channel in order to prioritize maintaining the connection with these adjacent terminals. Then, a new channel change notification is generated based on the determination result, and the generated channel change notification is transmitted to the adjacent wireless terminal 316.

  Next, the effect of this embodiment will be described. According to the present invention, the wireless terminal on the same mesh network is configured to notify information related to the channel change performed by the terminal on the network regardless of whether or not the terminal changes the channel. It is possible to know that there is a link loss due to a channel change due to interference from other wireless systems. Moreover, it is possible to prevent the loss of the link from occurring suddenly. Further, by using the channel change notification including the determination result of the adjacent terminal, it is possible to improve the convenience of determining the necessity of channel change using the channel change notification.

(Second Embodiment)
Next, a second embodiment will be described using the block diagram of the wireless communication terminal shown in FIG. In addition, the same number is attached | subjected about the structure similar to the said embodiment, and detailed description is abbreviate | omitted.

  The wireless communication terminal according to the present embodiment further includes a communication state management unit 65 in the configuration of the wireless communication terminal according to the first embodiment.

  The communication state management unit 65 manages at least one of communication quality such as received electric field strength and throughput with an adjacent wireless terminal and presence / absence of use of the power saving mode of the adjacent wireless terminal as communication state information. In addition to these pieces of information, the communication state management unit 65 may manage communication logs with adjacent wireless terminals.

  The channel selection determination unit 14 combines the channel change notification received from the adjacent communication terminal with the communication state information provided from the communication state management unit 65 to determine whether to change the channel in the own terminal.

  Since the operation of this embodiment is the same as that of the above embodiment, a description thereof will be omitted. The wireless system according to the present embodiment will be described as configuring a network as shown in FIG.

  When it is determined that neither the wireless communication terminal 312 nor the wireless communication terminal 313 changes the channel in the wireless communication terminal 312 and the wireless communication terminal 313, 0 indicating that the channel change is not performed is inserted in the switch decision of the channel change notification. A channel change notification is transmitted to the wireless terminal 314.

  The channel selection determination unit of the wireless terminal 314 takes into account the information managed by the communication state management unit 65 of the own terminal together with the channel change information of the switch decision of the channel change notification received from the wireless terminal 312 and the wireless terminal 313. Determine whether to change the channel. Here, it is assumed that it is determined not to change the channel. Then, a channel change notification newly generated based on the determination result is transmitted to the adjacent wireless communication terminal 316.

  On the other hand, the wireless terminal 315 makes a determination to change the channel based on the channel change notification from the wireless terminal 311, and sends to the wireless terminal 316 a channel change notification in which 1 indicating that the channel is changed is inserted in the Switch Decision 51. Send.

  The wireless communication unit 13 of the wireless communication terminal 316 receives a channel change notification in which Switch Decision 51 is 0 from the wireless terminal 314 and a channel change notification in which Switch Decision 51 is 1 from the wireless terminal 315.

  The channel selection determination unit 14 of the wireless communication terminal 316 provides communication quality such as reception field strength or throughput between the wireless communication terminal 314 and the wireless communication terminal 315 provided from the communication state management unit 65 together with the received channel change notification, or In combination with information such as whether or not the power saving mode is used, it is determined whether or not to change the channel in the terminal itself. For example, since the electric field strength with the wireless communication terminal 314 is low and the electric field strength with the wireless communication terminal 315 is high, it is determined that the channel is changed so as to maintain the link with the wireless communication terminal 315.

  Next, the effect of the second embodiment will be described. According to the present embodiment, even if the determination results of the adjacent terminals are different, it is possible to determine whether or not it is necessary to change the channel more appropriately by combining with other information. In particular, when a plurality of links are held, the determination can be made together with the actual communication status.

(Third embodiment)
Next, a third embodiment will be described. FIG. 7 shows a channel change notification format used in the present embodiment.

  The wireless communication system of the present embodiment forms a network as shown in FIG. 1 as in the first and second embodiments. Since the wireless communication terminal of the present embodiment has the same configuration as that of the above-described embodiment, the same configuration will be described with the same number. In the following description, the description is based on the configuration of the first embodiment, but the same configuration as that of the second embodiment may be used. In the case where the wireless terminal 311 detects interference, a case where a channel change notification is transmitted from the wireless terminal 311 to the wireless terminal 312 and the wireless terminal 313 will be described.

  As shown in FIG. 7, the channel change notification generated by the channel change notification generation unit 12 according to the present embodiment is the Channel Switch Mode (B0) of the Mesh Channel Switch Announcement element defined in IEEE802.11 TGs shown in FIG. -B7) Reserved (B3-B7) is a new item Switch Decision 71. In this Switch Decision 71, the judgment result of another terminal on the route is inserted. When the own terminal detects interference, 1 is inserted into Switch Decision 71. When a channel change notification is received from an adjacent terminal and it is determined that the channel is to be changed at the own terminal, a value obtained by adding 1 to the value described in Switch Decision 71 of the received channel change notification is inserted. On the other hand, when it is determined that the channel is not changed, the value of Switch Decision 71 of the received channel change notification is kept. Further, when the value described in Switch Decision 71 reaches the maximum value 31, no further addition is performed.

  Next, the operation of the embodiment of the present invention will be described with reference to the flowchart of FIG. In the following description, the case where the wireless communication terminal 311 detects interference will be described.

  When the interference detection unit 11 of the wireless communication terminal 311 detects interference (step S1), it is determined whether or not to change the channel (step S2). If the channel is not changed, the process returns to step S1. On the other hand, when the channel is changed, the channel change notification generator 12 generates a channel change notification (step S3). The wireless communication unit 13 transmits the generated channel change notification to the adjacent wireless communication terminal 312 and wireless communication terminal 313 (step S4).

  When the wireless communication unit 13 of the wireless communication terminal 312 and the wireless communication terminal 313 receives the channel change notification from the wireless communication terminal 311, the channel selection determination unit 14 uses the content of the received channel change notification. It is determined whether or not to change the current channel (step S5).

  If the channel is changed as a result of the determination, 1 is added to the value of Switch Decision 71 in the channel change notification (step S6). On the other hand, when the channel is not changed, the value of Switch Decision 71 in the channel change notification is maintained as it is (step S7).

  Below, it demonstrates using an Example. In the following description, a case where the wireless communication terminal 314 transmits a channel change notification from the wireless communication terminal 312, the wireless communication terminal 313, and the wireless communication terminal 316 will be described.

  When the wireless communication terminal 311 detects interference and determines to change the channel, a channel change notification in which 1 is set in Switch Decision 71 is transmitted to the wireless communication terminal 312 and the wireless communication terminal 313.

  If it is determined that neither the wireless communication terminal 312 nor the wireless communication terminal 313 changes the channel, the Switch Decision 71 is not changed and is transmitted to the wireless terminal 314 with the value of 1.

  On the other hand, if it is determined that both the wireless communication terminal 315 and the wireless communication terminal 316 perform channel change, 3 is written in the value of Switch Decision 71 in the channel change notification transmitted from the wireless communication terminal 316 to the wireless communication terminal 314. Will be.

  In the wireless communication terminal 314, the switch decision 71 of the channel change notification received from the wireless communication terminal 312 and the wireless communication terminal 313 is 1, while the switch decision 71 of the channel change notification received from the wireless communication terminal 316 is 3. It is adopted as a judgment material for channel change in its own terminal. If necessary, the determination may be made in combination with other information as in the second embodiment.

  Next, the effect of the third embodiment will be described. According to the present embodiment, it is possible to determine whether or not it is necessary to change the channel more appropriately by using the determination results of other terminals on the route in addition to the adjacent terminals.

  The terminal of the present invention described above can be configured by hardware as is apparent from the above description, but can also be realized by a computer program.

  Functions and operations similar to those of the above-described embodiments are realized by a processor that operates with a program stored in a program memory. Note that some of the functions of the above-described embodiments can be realized by a computer program.

  Although the present invention has been described with reference to the embodiments and examples, the present invention is not necessarily limited to the above-described embodiments and examples, and various modifications can be made within the scope of the technical idea. I can do it.

  The channel change method according to the present invention is useful for selecting a use channel between wireless terminals.

Claims (16)

A wireless system,
A wireless system that notifies a wireless terminal on the same mesh network of information related to a channel change performed by the terminal on the network.   2. The wireless system according to claim 1, wherein when the notification is received, the wireless terminal notifies an adjacent wireless terminal whether or not the terminal changes the channel along with the channel change.   When the notification is received, along with the channel change, whether or not the own terminal changes the channel is notified to an adjacent wireless terminal together with information on the channel change of another wireless terminal. The wireless system described.   The radio system according to any one of claims 1 to 3, wherein the terminal determines whether to change the channel based on the notification.   4. The method according to claim 1, wherein the terminal determines whether or not to change the channel based on the notification and a communication state with a wireless terminal that has transmitted the notification. Wireless system. A wireless terminal,
A wireless terminal, comprising: a wireless terminal on the same mesh network that has a notification unit that generates information related to a channel change performed by a terminal on the network and notifies an adjacent wireless terminal.   The wireless terminal according to claim 6, wherein, when the notification is received, the wireless terminal notifies an adjacent wireless terminal whether or not the terminal changes the channel along with the channel change.   The notification means, when receiving the notification, notifies the adjacent wireless terminal whether or not the own terminal changes the channel along with the channel change together with information on the channel change of other wireless terminals. The wireless terminal according to claim 6.   The wireless terminal according to claim 6, further comprising: a determination unit that determines whether or not the own terminal changes a channel based on the notification.   9. The method according to claim 6, further comprising a determination unit that determines whether or not the own terminal changes a channel based on the notification and a communication state with a wireless terminal that has transmitted the notification. The wireless terminal according to the above. A wireless communication method,
A wireless communication method comprising: notifying a wireless terminal on the same mesh network of information related to a channel change performed by a terminal on the network.   The wireless communication method according to claim 11, wherein upon receiving the notification, the wireless terminal notifies an adjacent wireless terminal whether or not the terminal changes the channel with the channel change.   12. When receiving the notification, along with the channel change, whether or not the own terminal changes the channel is notified to an adjacent wireless terminal together with information on the channel change of another wireless terminal. The wireless communication method described.   The radio communication method according to any one of claims 11 to 13, wherein the terminal determines whether to change the channel based on the notification.   The terminal according to any one of claims 11 to 13, wherein the terminal determines whether or not to change the channel based on the notification and a communication state with a wireless terminal that has transmitted the notification. Wireless communication method. A program of a wireless terminal, wherein the program
A program that causes a wireless terminal on the same mesh network to function as a notification unit that generates information related to a channel change performed by a terminal on the network and notifies an adjacent wireless terminal.

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