JP2018148279A - COMMUNICATION DEVICE, COMMUNICATION DEVICE CONTROL METHOD, AND PROGRAM - Google Patents

Abstract

Channel switch control is appropriately performed according to a function of a partner apparatus. A communication device that configures a network and can communicate with a plurality of other communication devices in the network switches a channel used for communication with the communication device from each of the plurality of other communication devices. A connection request including information indicating whether or not the communication device has a function of notifying the communication device that the switching of the channel has been completed, and the plurality of other requests based on the received connection request It is determined whether or not the communication device has the function, and based on the determination result, it is controlled whether or not the channel being used for communication with the communication device is switched to another channel at the time of the determination. To do. [Selection] Figure 11

Description

  The present invention relates to a communication device, a communication device control method, and a program.

  In recent years, wireless LAN (Local Area Network) systems compliant with IEEE802.11 have been widely used. This wireless LAN includes a base station called an access point (hereinafter referred to as AP) and a station (hereinafter referred to as STA) that is in a wireless connection state with the AP. AP and STA communicate using channels of the same frequency. However, if there are many other networks in the same channel as the AP and STA, or in the vicinity of the AP and STA, radio interference frequently occurs and the communication speed decreases. In such a case, it is effective for AP and STA to change to another channel (hereinafter referred to as channel switch).

  Wireless LAN shares frequency with weather radar in W53 and W56 in 5GHz band. For this reason, APs and STAs are required to perform channel switching in wireless LANs when radar is detected on the channel being used.

  Further, as a technique for performing channel switching, Channel Switch Announcement (hereinafter referred to as CSA) and Extended Channel Switch Announcement (hereinafter referred to as ECSA) have been proposed. CSA and ECSA compliant with IEEE802.11 are action frames (signals) transmitted from the AP to notify the STA of the channel switch before the AP performs the channel switch, and include channel information after the channel switch. The ECSA further includes information on the currently communicating area. The STA that has received the CSA can connect after performing an authentication procedure such as key exchange again to the AP after the channel switch. On the other hand, the STA that has received the ECSA can maintain the connection with the AP by moving to the channel after the channel switch without performing the authentication process again. Also, CSA and ECSA can be notified by adding them as information elements to Beacon periodically transmitted by the AP instead of an action frame.

  As described above, since the STA that has received the CSA and switched the channel performs the authentication procedure again and reconnects to the AP, it takes time to complete the connection. In addition, the STA that has received the CSA may operate in a state in which the connection with the AP is disconnected until the authentication is completed by performing a channel switch, in which case communication is temporarily disconnected. In particular, when many STAs are connected to a single AP, the AP re-authenticates each STA. Therefore, the STA that re-authenticates with the AP lasts for a long time. End up.

  For such a problem, Patent Document 1 proposes a method for realizing a channel switch without disconnecting communication. First, the AP notifies the STA that channel switching is to be performed before performing channel switching. In response to the channel switch notification, the STA performs the channel switch, and if successful, notifies the AP that the channel switch has been completed. As a result, the STA that has performed the channel switch can save the trouble of performing the re-authentication process.

JP 2007-325315 A

  In Patent Document 1, it is assumed that the STA can perform channel switch completion notification. However, if the STA does not have a function of performing such notification, for example, the following problem occurs. In other words, an STA that does not have a function of notifying channel switch completion does not notify the AP of channel switch completion even when the channel switch is completed. For this reason, the AP does not know whether the STA has succeeded in the channel switch, and even if it is successful, the AP cannot grasp the communication capability of the STA. In that case, the AP may send data to the STA at an inappropriate rate. On the other hand, even if the AP does not have a function to process the channel switch completion notification from the STA, even if the AP receives the channel switch completion notification from the STA, the AP cannot recognize the notification correctly and The communication ability cannot be grasped.

  The present invention has been made in view of the above problems, and an object of the present invention is to appropriately perform channel switch control in accordance with the function of the counterpart device.

  As a means for achieving the above object, the communication apparatus of the present invention has the following configuration. That is, a communication device that configures a network and can communicate with a plurality of other communication devices in the network, and the channel used for communication with the communication device is switched from each of the plurality of other communication devices. A receiving unit that receives a connection request including information indicating whether or not the communication device has a function of notifying the communication device that the switching of the channel has been completed, and based on the connection request received by the receiving unit And determining means for determining whether or not the plurality of other communication devices have the function, and being used in communication with the communication device at the time of the determination based on the determination result by the determining means Switching means for controlling whether to switch one channel to another channel.

  According to the present invention, it is possible to appropriately perform channel switch control according to the function of the counterpart device.

1 is a schematic diagram of a wireless LAN system in an embodiment. FIG. 3 is a diagram illustrating an example of a functional configuration of a GO 101 according to the first embodiment. 6 is a sequence example of determining whether to respond to a channel switch completion notification in the first embodiment. Example of frame structure of Association Request. 6 is a flowchart example of channel switch completion notification availability determination processing according to the first embodiment. 4 is a flowchart example of channel switch execution determination processing according to the first embodiment. 7 is a sequence example in the case of S602 in FIG. The sequence example in the case of S603 in FIG. 6 is a frame configuration example of a channel switch completion notification in the embodiment. FIG. 10 is a diagram illustrating an example of a functional configuration of a GO 101 according to a second embodiment. 4 is a flowchart example of channel switch execution determination processing according to the first embodiment. FIG. 12 is a sequence diagram in the case of S1103 in FIG. FIG. 3 is a diagram illustrating an example of a functional configuration of a CL 102 according to the first embodiment. 10 is a sequence example of determining whether or not to accept a channel switch completion notification in the second embodiment. Example of frame structure of Association Request in the embodiment 6 is a flowchart example of channel switch completion notification availability determination processing according to the first embodiment. 10 is a flowchart example of channel switch completion notification method determination processing according to the third embodiment. 10 is a sequence example when GO 101 in the third embodiment does not support channel switch completion notification. 10 is a sequence example in the case where GO 101 in the third embodiment supports channel switch completion notification.

  Hereinafter, the present invention will be described in detail based on the embodiments with reference to the accompanying drawings. The configurations shown in the following embodiments are merely examples, and the present invention is not limited to the illustrated configurations. In the following, an example using a wireless LAN system compliant with the IEEE802.11 series standard will be described, but the communication method is not limited to this.

<Embodiment 1>
FIG. 1 shows a network configuration example in the first embodiment. The GO 101 as an AP is a P2P Group Owner (hereinafter referred to as GO) compliant with the Wi-Fi Peer-to-Peer (hereinafter referred to as P2P) standard. Further, CL 102 and CL 103 as STAs are P2P Clients (hereinafter referred to as CL) conforming to the P2P standard. CL102 and CL103 participate in the wireless network 104 formed by GO101. This embodiment relates to GO101. In the following description, CL102 and CL103 are simply referred to as CL.

  In the present embodiment, it is assumed that GO 101 can communicate with CL 102 and GO 101 using channel 6 in the 2.4 GHz band. Also, it is assumed that GO101 in this embodiment does not operate on channels that require radar detection, such as W53 and W56. Also, CL102 and CL103 are assumed to support the IEEE802.11n standard (HT (High Throughput)) in the 2.4 GHz band and the IEEE802.11ac standard (VHT (Very High Throughput)) in the 5 GHz band.

  FIG. 2 is a diagram illustrating an example of the functional configuration of GO101. Whether the function determination unit 201 has a function of sending a channel switch completion notification (ie, whether or not the channel switch completion notification is supported) to CLs participating in the wireless network 104 (that is, CL102 and CL103). Determine. Detailed operation of the function determination unit 201 will be described later with reference to FIG. The congestion detection unit 202 detects the frequency of radio wave interference in the currently used channel and the congestion of the channel. The channel switch determination unit 203 determines whether to perform channel switching according to the detection result from the congestion detection unit 202 and the determination result from the function determination unit 201. Detailed operation of the channel switch determination unit 203 will be described later with reference to FIG. The channel switch control unit 204 performs control when performing the channel switch. The wireless control unit 205 performs control for performing communication with a plurality of other wireless LAN devices.

  Each functional block shown in FIG. 2 is configured by hardware or software. When configured as software, a computer program for realizing each function is stored in the storage unit (not shown) of GO101, and the CPU (Central Processing Unit, not shown) included in GO101 executes the program. This function is realized by.

  Next, the operation of the function determination unit 201 of GO 101 will be described with reference to FIG. FIG. 3 shows a process for the function determination unit 201 to determine whether or not the CL corresponds to the channel switch completion notification (for example, whether or not a message indicating that the channel switch has been completed can be transmitted). It is a flowchart to explain. The processing shown in FIG. 3 is performed when the CLs 102 and 103 participate in the network that the GO 101 configures. Here, communication between GO101 and CL102 will be described as an example.

  When the CL 102 participates in the wireless network configured by the GO 101, the CL 102 sends an Association Request to the GO 101 (S301). The Association Request is a frame transmitted in order to make a connection request from the STA to the AP, which is defined in the IEEE 802.11 standard. In the present embodiment, when the CL 102 is compatible with the channel switch completion notification, a flag indicating that it is compatible with the channel switch completion notification is added to the Association Request and transmitted to the GO 101 (S301). On the other hand, if the CL 102 does not support the channel switch completion notification, the Association Request is transmitted to the GO 101 without adding the flag (S301). The detailed configuration of the Association Request will be described later with reference to FIG.

  When receiving an Association Request from the CL 102 via the wireless control unit 205, the function determination unit 201 of the GO 101 returns an Association Response as a response (S302). Thereafter, the function determination unit 201 of the GO 101 determines whether or not the CL 102 that has transmitted the Association Request corresponds to the channel switch completion notification (S303). The process of determining whether or not it corresponds to the channel switch completion notification (determining whether or not to support the channel switch completion notification) will be described later with reference to FIG.

  FIG. 4 shows the frame structure of the Association Request. As shown in FIG. 4A, the Association Request is composed of Capability, Listen Interval, SSID, Supported rates (401), HT Capabilities (402) indicating the presence / absence of HT capability, and the like according to the IEEE 802.11 standard. Supported rates (401) indicates a communication rate that can be supported. Since CL102 and CL103 of this embodiment are compatible with the IEEE802.11ac standard, VHT Capabilities (403) indicating the presence or absence of VHT capability is also added when participating in a 5 GHz band wireless network. From these capability information (402, 403), GO101 can grasp the communication capability of CL102 and CL103.

  In the P2P standard, a P2P Information Element (hereinafter referred to as P2P IE) is defined as one of the components of the Association Request (404). P2P IE (404) includes OUI Type (403) and P2P Attributes (406). P2P Attributes (406) includes P2P Capabilities (407), and P2P Capabilities (407) includes Device Capability Bitmap (408).

  The configuration of Device Capability Bitmap (408) is shown in FIG. In the Device Capability Bitmap (408), information indicating the device capability is described from the 0th bit to the 5th bit, but the 6th to 7th bits are reserved bits in the P2P standard. Therefore, in this embodiment, the sixth bit (409) of the Device Capability Bitmap is used as a channel switch completion notification capability flag for describing the presence / absence of a function for sending a channel switch completion notification. The CL corresponding to the channel switch completion notification sets the channel switch completion notification capability flag in the Association Request to 1. On the other hand, the CL that does not support the channel switch completion notification keeps the channel switch completion notification capability flag set to 0 (zero). In the conventional CL, the sixth bit (409) of Device Capability Bitmap is not used and is always set to 0, so it does not support channel switch completion notification (has a function to perform channel switch completion notification) Not).

  Next, processing for determining whether or not to accept channel switch completion notification (S303 in FIG. 3) will be described with reference to FIG. FIG. 5 is a flowchart of processing for determining whether or not to accept a channel switch completion notification in the present embodiment. The processing in FIG. 5 is performed by the function determination unit 201 of GO101.

  The function determination unit 201 analyzes the Association Request received from the CL via the radio control unit 205, and determines whether or not the CL that transmitted the Association Request corresponds to the channel switch completion notification (S501). When the channel switch completion notification capability flag in the Association Request is set to 1 (Yes in S501), the function determination unit 201 determines that the source CL corresponds to the channel switch completion notification ( S502). On the other hand, when the channel switch completion notification capability flag is 0 (No in S501), it is determined that the source CL does not support the channel switch completion notification (S503).

  Next, the operation of the channel switch determination unit 203 will be described with reference to FIG. FIG. 6 is a flowchart of channel switch execution determination processing in the present embodiment.

  The channel switch determination unit 203 determines, based on the determination result by the function determination unit 201, whether there is even one CL that does not support the channel switch completion notification in the wireless network configured by the GO 101 (S601). If there is even one CL that does not correspond to the channel switch completion notification (Yes in S601), the channel switch determination unit 203 determines not to perform the channel switch (S602). Note that the sequence in the case of S602 will be described later with reference to FIG. On the other hand, when all the CLs participating in the wireless network 104 configured by the GO 101 support the channel switch completion notification (No in S601), the channel switch determination unit 203 transmits to each CL via the wireless control unit 205. It is determined that ECSA is transmitted to perform channel switching (S603). Note that the sequence in the case of S603 will be described later with reference to FIG.

  FIG. 7 shows a sequence in the case of S602 in FIG. Here, CL102 corresponds to the channel switch completion notification, but CL103 does not correspond to the channel switch completion notification.

  When the GO101 congestion detection unit 202 detects congestion on the currently used channel 6, the channel switch determination unit 203 performs channel switch execution determination processing to determine whether the channel switch can be executed. Implement (S701). Since the CL 103 does not correspond to the channel switch completion notification, the channel switch determination unit 203 determines not to perform the channel switch (S602). In this case, the GO 101 stays in the currently used channel 6 and does not perform channel switching. According to this sequence, when there is a CL that does not support the channel switch completion notification, the GO 101 does not perform channel switching forcibly, and as a result, communication can be prevented from being interrupted.

  FIG. 8 shows a sequence in the case of S603 in FIG. Here, both CL102 and CL103 correspond to the channel switch completion notification. When the GO101 congestion detection unit 202 detects radio wave interference in the currently used channel 6, the GO101 channel switch determination unit 203 performs channel switch execution determination in order to determine whether the channel switch can be executed. Processing is performed (S801). In this sequence, since both CL102 and CL103 correspond to the channel switch completion notification, the channel switch determination unit 203 determines to perform the channel switch by transmitting ECSA (S603).

  When the channel switch determination unit 303 of GO 101 decides to perform ECSA and perform channel switching, it transmits ECSA to each of CL 102 and CL 103 via radio control unit 205 to notify that channel switching is to be performed ( S802). In S802, GO101 transmits ECSA to CL102 and CL103 by unicast, but it may transmit by broadcast. In the example of FIG. 8, it is assumed that the GO 101 switches from the 2.4 GHz band channel 6 to the 5 GHz band channel 36.

  After transmitting the ECSA, the channel switch control unit 204 of the GO 101 performs a channel switch to the channel 36 in use at that time (at least at the time of the channel switch execution determination process (S801)) (S803). The CL 102 and CL 103 that have received the ECSA perform channel switching to the channel 36 (S804, S805). In FIG. 8, since CL102 and CL103 correspond to the channel switch completion notification, the channel switch completion notification is transmitted to the GO 101 after the channel switch is completed (S806). In the present embodiment, an extension of the P2P action P2P action frame is used as the channel switch completion notification.

  FIG. 9 shows a frame configuration of the channel switch completion notification. The channel switch completion notification is an extension of the P2P action frame of the P2P standard and includes Category, OUI subtype (901), Elements (902), and the like. Elements (902) describes HT Capabilities (903) when supporting the IEEE802.11n standard, and VHT Capabilities (904) when supporting the IEEE802.11ac standard in the 5 GHz band. OUI subtype (901) indicates the type of P2P action frame by its value, and the P2P standard already defines the type of P2P action frame when the value of OUI subtype is 0 to 3. On the other hand, 4 to 255 are reserved slots. Therefore, in this embodiment, the P2P action frame when the value of OUI subtype is specified as 4 is used as a channel switch completion notification.

  In addition, since CL102 and CL103 are compatible with IEEE802.11n and IEEE802.11ac standards in the 5 GHz band after channel switching, HT Capabilities (903) and VHT are included in the channel switch completion notification transmitted by CL102 and CL103. Capabilities (904) are both described.

  The GO 101 that has received the channel switch completion notification from the CL 102 and CL 103 can recognize that the CL 102 and CL 103 have completed the channel switch to the channel 36. Therefore, the GO 101 can resume communication without re-taking the procedure of connection such as Association Request and key exchange.

  The GO 101 can grasp the communication capabilities of the CL 102 and CL 103 in the channel 36 after the switch by analyzing the HT / VHT Capabilities in the channel switch completion notification. This will be described more specifically. The Association Request (S301) sent when CL102 joined the GO101 wireless network 104 that originally communicated on the 2.4 GHz band channel 6 described the HT capability of the channel currently used. . Therefore, GO101 knows the communication capability of CL102 in the 2.4 GHz band, that is, CL102 is compatible with the IEEE802.11n standard. However, after the channel switch to the channel 36 in the 5 GHz band, the GO 101 cannot grasp that the CL 102 is compatible with the IEEE802.11ac standard without a channel switch completion notification. As a result, the IEEE802.11ac standard that can communicate at a higher communication rate is not used, the IEEE802.11n standard is used continuously, and communication is performed at a slow communication rate despite the ability to communicate with VHT. CL102 and CL103 send a channel switch completion notification describing the communication capability information when the channel switch is completed, and GO101 receives it, so GO101 can send and respond to data at a communication rate not compatible with CL102 and CL103. This prevents you from overlooking the higher communication rates.

  As described above, in the present embodiment, when there is a CL that does not support the channel switch completion notification, the GO 101 prevents communication from being interrupted without forcibly performing channel switching. Also, if all CLs support channel switch completion notification, GO101 sends ECSA and causes CL to send channel switch completion notification. It becomes possible to transmit data at an appropriate communication rate.

<Embodiment 2>
In the second embodiment, an embodiment in which channel switching must be performed at the time of radar detection will be described. This embodiment relates to GO101. Hereinafter, the description of the same points as in the first embodiment will be omitted.

  The network configuration in this embodiment is the same as that of FIG. 1 described in the first embodiment. However, in this embodiment, the channel 53 of W53 in the 5 GHz band is used for communication between GO101 and CL102 and between GO101 and CL103. Since W53 and W56 in the 5 GHz band share the frequency with weather radar, it is necessary to move from the currently used channel to another channel when radar is detected.

  Further, the GO 101 in this embodiment is a device that can operate the STA function simultaneously with the GO function (hereinafter referred to as a concurrent operation). When the GO 101 is in a concurrent operation, the GO 101 participates in a wireless network of another AP (not shown) by the STA function in addition to the wireless network 104 configured by the GO function. The channels used for the STA function and GO function are the same. On the other hand, CL102 and CL103 are assumed to be compatible with the IEEE802.11n standard (HT) and the IEEE802.11ac standard (VHT).

  FIG. 10 is a functional block diagram of the GO 101 in the present embodiment. Congestion detection unit 1002 and channel switch control unit 1006 are the same as function determination unit 201, congestion detection unit 202, and channel switch control unit 204 in FIG. The radar detection unit 1003 detects the presence / absence of radar in the currently used channel. The concurrent operation detection unit 1004 determines whether or not connection with a wireless network of another AP that operates on a channel different from the channel used in the wireless network 104 configured by the GO 101 is started.

  The channel switch determination unit 1005 determines whether or not to execute the channel switch based on the determination result by the function determination unit 1001 and the detection results by the congestion detection unit 1002, the radar detection unit 1003, and the concurrent operation detection unit 1004 To do. Detailed operation of the channel switch determination unit 1005 will be described later with reference to FIG. The wireless control unit 1007 performs control for communicating with other wireless LAN devices.

  Each functional block shown in FIG. 10 is configured by hardware or software. When configured as software, a computer program for realizing each function is stored in the storage unit (not shown) of GO101, and the CPU (Central Processing Unit, not shown) included in GO101 executes the program. This function is realized by.

  Compared with the first embodiment, the present embodiment is different in channel switch execution determination processing in S701 in FIG. 7 and S801 in FIG. This process will be described with reference to FIG. FIG. 11 is a flowchart of channel switch execution determination processing in the present embodiment.

  The channel switch determination unit 1005 determines whether radar is detected by the W53 or W56 currently used by the radar detection unit 1003 (S1101). When the radar is not detected (No in S1101), the concurrent operation detection unit 1004 determines whether or not the GO101 has started a concurrent operation on a channel different from the channel currently used (S1105). If it is determined that the concurrent operation has started (Yes in S1105), either radar or concurrent operation is detected. In this case, the GO 101 must always switch the channel. First, the channel switch determination unit 1005 determines whether or not there is even one CL that does not support the channel switch completion notification in the wireless network configured by the GO 101 (S1102). If there is at least one CL that does not support the channel switch completion notification (Yes in S1102), the channel switch determination unit 1005 uses ECSA for the CL corresponding to the channel switch completion notification, and CSA for the non-compatible CL. It is determined to transmit and perform channel switching (S1103). When all the CLs correspond to the channel switch completion notification (No in S1102), the channel switch determination unit 1005 determines to perform the channel switch by transmitting ECSA to all the CLs (S1104).

  On the other hand, if neither radar nor concurrent operation is detected (No in S1105), the channel switch determination unit 1005 determines whether there is a CL that does not support channel switch completion notification in the wireless network configured by GO101. Determination is made (S1106). When congestion is detected by the congestion detection unit 1002, the GO 101 does not necessarily need to perform a channel switch. If there is even one CL that does not correspond to the channel switch completion notification (Yes in S1006), the channel switch determination unit 1005 determines not to perform the channel switch (S1107). When all the CLs correspond to the channel switch completion notification (No in S1006), the channel switch determination unit 1005 determines to perform the channel switch by transmitting ECSA to all the CLs (S1108).

  The sequence of S1103 will be described later with reference to FIG. Since S1104, S1107, and S1108 are the same as S602 or S603 of FIG. 6 described in the first embodiment, detailed description of the sequence is omitted. In other words, the channel switch sequence of S1104 and S1108 (when it is determined to switch the channel by transmitting ECSA) is the same as that in FIG. 8 described in the first embodiment. Further, the sequence of S1107 (when it is determined not to switch the channel) is the same as that in FIG. 7 described in the first embodiment.

  FIG. 12 shows a sequence in the case of S1103 in FIG. Here, CL102 corresponds to the channel switch completion notification, and CL103 does not correspond to the channel switch completion notification.

  When the congestion detection unit 1002 detects congestion, the radar detection unit 1003 detects radar, or the concurrent operation detection unit 1004 detects concurrent operation, the channel switch determination unit 1005 of GO101 performs channel switch execution determination processing. Implement (S1201). Here, it is assumed that the radar detection unit 1003 detects a radar in the channel 56 currently used. Since CL103 does not support channel switch completion notification, channel switch determination unit 1005 transmits ECSA to CL102 corresponding to channel switch completion notification and CSA to non-compatible CL103 to perform channel switching. Determine (S1103). Subsequently, the channel switch determination unit 1005 transmits ECSA to the CL 102 corresponding to the channel switch completion notification (S1202) and CSA to the non-compatible CL 103 via the radio control unit 1007 (S1203), Announce that the channel will be switched. In the example of FIG. 12, it is assumed that the GO 101 switches the channel from the channel 56 in the 5 GHz band to the channel 6 in the 2.4 GHz band. Note that the processing order of S1202 and S1203 may be reversed.

  GO101 performs channel switch to channel 6 after transmitting ECSA and CSA (S1204). The CL 102 that has received ECSA and the CL 103 that has received CSA perform channel switching to channel 6 (S1205, S1206). Since the CL 102 corresponds to the channel switch completion notification, the channel switch completion notification is transmitted to the GO 101 after the channel switch is completed (S1207). On the other hand, after the channel switch is completed, the CL 103 that does not support the channel switch completion notification transmits an Association Request to the GO 101 to request reconnection (S1208). GO101 which received Association Request transmits Association Response to CL103, and permits a connection (S1209). For example, when the connection method is WPA-PSK or WPA2-PSK, the GO 101 needs to authenticate by 4-way Hand Shake for key exchange after receiving the Association Response.

  The HT / VHT Capabilities (402) is described in the Association Request (S301) sent when the CL 102 participates in the GO101 wireless network 104 originally communicating on the channel 56 in the 5 GHz band. Therefore, GO101 was able to grasp the communication capability of CL102 in the 5 GHz band, that is, CL102 is compatible with the IEEE802.11n standard and the IEEE802.11ac standard in the 5 GHz band. However, after channel switching to channel 6 in the 2.4 GHz band, the GO 101 cannot grasp that the CL 102 is compatible with the IEEE802.11n standard in the 2.4 GHz band without a channel switch completion notification. Therefore, the GO 101 does not know which communication rate should be transmitted to the CL 102, and may transmit data at a communication rate not supported by the CL 102.

  In order to solve this, as described in FIG. 9, in this embodiment, the HT / VHT capability is described in the channel switch completion notification. The GO 101 that has received the channel switch completion notification from the CL 102 can analyze the HT Capabilities in the channel switch completion notification and grasp the communication capability of the CL 102 in the channel 6. In addition, it is possible to recognize that the CL 102 has completed the channel switch to the channel 6 by the channel switch completion notification, and it is possible to resume communication without re-taking the connection procedure such as the Association Request. On the other hand, the CL 103 that does not support the channel switch completion notification will repeat the connection procedure. However, since the HT Capabilities after the channel switching of the CL 103 are described in the Association Request, the GO 101 can grasp the communication capability of the CL 103 in the channel 6.

  As described above, in this embodiment, when channel switching must be performed, GO101 sends ECSA to CL corresponding to channel switch completion notification, and channel switch completion notification after channel switching. Request. Further, the GO 101 transmits a CSA to a CL that does not support the channel switch completion notification, and requests reconnection by an Association Request. As a result, it is possible to prevent data from being transmitted at a communication rate that is not supported while reducing reconnection and authentication.

<Embodiment 3>
In the present embodiment, an embodiment in which the GO 101 does not support channel switch completion notification will be described. This embodiment relates to CL102. Hereinafter, the description of the same points as in the first embodiment will be omitted.

  The network configuration in this embodiment is the same as that of FIG. 1 described in the first embodiment. However, in this embodiment, it is assumed that the CL 103 does not exist and the GO 101 and CL 102 constitute a network. In addition, channel 6 in the 2.4 GHz band is used for communication between GO101 and CL102. Also, CL102 is assumed to support channel switch completion notification.

  FIG. 13 is a functional block diagram of the CL 102 in the present embodiment. The channel switch control unit 1303 and the radio control unit 1304 are the same as the channel switch control unit 204 and the radio control unit 205 in FIG. The function determination unit 1301 determines whether or not the GO 101 has a function of processing a channel switch completion notification. Detailed operation of the function detection unit 301 will be described later with reference to FIG. Notification method determining section 1302 determines the channel switch execution method according to the detection result of function determining section 1301. Detailed operation of the notification method determination unit 1302 will be described later with reference to FIG.

  Compared with the first embodiment, the present embodiment is different in that the process of S303 in FIG. The processing of the CL 102 in the present embodiment will be described using FIG. 14 and FIG.

  FIG. 14 is a sequence for determining whether or not the GO 101 is compatible with the channel switch completion notification. The process of FIG. 14 is performed when the CL 102 participates in a wireless network configured by the GO 101. “GO 101 supports channel switch completion notification” corresponds to GO 101 having a function for GO 101 to recognize and process a channel switch completion notification sent from CL 102. When the GO corresponding to the channel switch completion notification receives the channel switch completion notification from the CL 102, it can recognize that the source CL 102 has switched to the channel. Furthermore, the GO 101 can transmit data to the CL 102 at an appropriate communication rate based on the communication capability information included in the channel switch completion notification.

  When the CL 102 participates in the wireless network configured by the GO 101, the CL 102 sends an Association Request to the GO 101 (S1401). In response to this, the GO 101 transmits an association response to the CL 102 (S1402). The Association Response is a frame defined by the IEEE 802.11 standard and transmitted to allow the AP to connect to the STA.

  In this embodiment, the GO 101 corresponding to the channel switch completion notification adds a flag indicating that it corresponds to the channel switch completion notification to the Association Response, and transmits it to the CL 102 (S1402). On the other hand, the GO 101 that does not support the channel switch completion notification does not add such a flag and transmits an Association Response to the CL 102 (S1402). The detailed configuration of Association Response will be described later with reference to FIG.

  The CL 102 that has received the Association Response from the GO 101 determines whether the GO 101 is compatible with the channel switch completion notification (S1403). The process of determining whether or not it corresponds to the channel switch completion notification (determining whether or not to support the channel switch completion notification) will be described later using FIG.

  FIG. 15 shows the frame structure of Association Response. As shown in FIG. 15A, the Association Response frame is composed of Capability, Status code, AID, Supported rates, HT Capabilities (1501) indicating the presence / absence of HT capability, and the like according to the IEEE 802.11 standard. When using the 5 GHz band and supporting VHT, VHT Capabilities (1502) indicating VHT capability is also added. From these capability information (1501, 1502), CL102 can grasp the communication capability of GO101.

  Similar to the Association Request described in the first embodiment, the P2P standard defines a P2P Information Element (P2P IE) as one of the components of the Association Response (1503). Since the configuration of the P2P IE is the same as that of FIG. 4 described in the first embodiment, the description thereof is omitted. As in the first embodiment, in this embodiment, the sixth bit (1504) of the Device Capability Bitmap is used as a channel switch completion notification capability flag for describing the presence or absence of a function for recognizing and processing the channel switch completion notification. use. If the GO 101 supports channel switch completion notification, the channel switch completion notification capability flag in Association Response is set to 1. On the other hand, when the GO 101 does not support the channel switch completion notification, the channel switch completion notification capability flag is kept at 0 (zero). In the conventional GO, the sixth bit (1504) of the Device Capability Bitmap is not used and is always set to 0, so CL does not support channel switch completion notification (understand channel switch completion notification) It has a function).

  Next, processing for determining whether or not to accept a channel switch completion notification (S1403 in FIG. 14) will be described with reference to FIG. FIG. 16 is a flowchart of channel switch completion notification availability determination processing in the present embodiment. The processing in FIG. 16 is performed by the function determination unit 1301 of the CL 102 after the CL 102 participates in the wireless network 104 formed by the GO 101 and an Association Response is returned.

  The function determination unit 1301 analyzes the Association Response received from the GO 101, and determines whether the GO 101 is compatible with the channel switch completion notification (S1601). When the channel switch completion notification enable / disable flag in the Association Response is set to 1 (Yes in S1601), the function determination unit 1301 determines that GO101 corresponds to the channel switch completion notification (S1602). On the other hand, when the channel switch completion notification enable / disable flag is 0 (No in S1601), the function determining unit 1301 determines that GO101 does not support the channel switch completion notification (S1603).

  Next, the operation of the notification method determination unit 1302 will be described with reference to FIG. FIG. 17 is a flowchart of channel switch completion notification method determination processing in the present embodiment.

  The notification method determination unit 1302 determines whether the GO 101 connected to the CL 102 corresponds to the channel switch completion notification based on the determination result of the function determination unit 1301 (S1701). If GO101 does not support channel switch completion notification (Yes in S1701), notification method determining section 1302 determines to re-establish an association request after channel switch (S1702). On the other hand, when the GO 101 corresponds to the channel switch completion notification (No in S1701), the notification method determination unit 1302 determines to transmit the channel switch completion notification after the channel switch (S1703).

  FIG. 18 shows a sequence when the GO 101 in this embodiment does not support channel switch completion notification. First, the GO 101 decides to perform channel switching for some reason, and then notifies the CL 102 of channel switching by transmitting ECSA (S1801). Here, it is assumed that GO 101 is channel-switched from channel 6 in the 2.4 GHz band to channel 36 in the 5 GHz band. After transmitting the ECSA, the GO 101 performs channel switching to the channel 36 (S1802). The CL 102 that has received the ECSA performs a channel switch to the channel 36 (S1803).

  After the channel switch is completed, the CL 102 performs a channel switch completion notification method determination process (S1804). Since GO101 does not support channel switch completion notification (Yes in S1701 in FIG. 17), notification method determining section 1302 determines to transmit an Association Request after channel switching (S1702). Subsequently, the notification method determination unit 1302 of the CL 102 transmits an Association Request to the GO 101 via the wireless control unit 1304 to request reconnection (S1805). The GO 101 that has received the Association Request transmits an Association Response to the CL 102 to permit connection (S1806). Since Association Request and Association Response describe the HT / VHT capability of each transmitting device, GO 101 and CL 102 can grasp each other's communication capability.

  In FIG. 19, the sequence until the GO 101 in the present embodiment performs the channel switch completion notification method determination process (S1901) is the same as that in FIG. Since the GO 101 corresponds to the channel switch completion notification, the notification method determination unit 1302 determines to transmit the channel switch completion notification after the channel switch (S1703). Subsequently, the notification method determination unit 1302 of the CL 102 transmits a channel switch completion notification to the GO 101 via the radio control unit 1304 (S1902). Since the HT / VHT capability is described in the channel switch completion notification, the GO 101 can grasp the communication capability of the CL 102.

  When GO 101 transmits ECSA, GO 101 does not always support channel switch completion notification. Therefore, even if the CL 102 that has received ECSA transmits a channel switch completion notification to the GO 101 after the channel switch, the GO 101 may not recognize the channel switch completion notification and may not process it. In this case, the GO 101 cannot grasp the communication capability of the CL, and transmits data at an inappropriate communication rate.

  In this embodiment, when the GO 101 does not support the channel switch completion notification, the CL 102 sends an association request, and the GO 101 cannot grasp the communication capability of the CL 102 and transmits data at an inappropriate communication rate. To prevent that. Further, when the GO 101 is compatible with the channel switch completion notification, the CL 102 transmits the channel switch completion notification, thereby making it possible to save reconnection and authentication.

(Other embodiments)
In the first to third embodiments, it is determined whether the opposite device supports the channel switch completion notification by describing the channel switch completion notification capability flag in the Association Request and Association Response. Also good.

  For example, the Association Request in FIG. 4 describes Supported rates (401) and Extended Supported rates indicating the communication rate supported by the device that transmitted the Association Request. The device that has received the Association Request analyzes this information, and if the supported communication rate is below a certain value, the device uses an old standard and does not support channel switch completion notification. May be determined. For the same reason, if there is no description of HT Capabilities (402) or VHT Capabilities (403) in the Association Request, it may be determined that the channel switch completion notification is not supported.

  Also, the P2P IE (406) in the Association Request describes an OUI Type (405) indicating the type of the corresponding P2P standard. Therefore, it is possible to determine whether or not the channel switch completion notification is supported by the value of OUI Type (405).

  Further, the channel switch completion notification frame may have any configuration as long as it includes information on the communication capability of the device such as HT Capabilities and VHT Capabilities, and the P2P action frame configuration shown in FIG. 9 is required. There is no. In addition, although CSA and ECSA that notify the channel switch are notified by an action frame in FIGS. 8, 9, 18, and 19, they are not necessarily notified by an action frame. CSA and ECSA information may be notified as a Beacon Information element that the AP periodically transmits.

  The present invention supplies a program that realizes one or more functions of the above-described embodiments to a system or apparatus via a network or a storage medium, and one or more processors in a computer of the system or apparatus read and execute the program This process can be realized. It can also be realized by a circuit (for example, ASIC) that realizes one or more functions.

101 GO, 102 to 103 CL, 201 function determination unit, 202 congestion detection unit, 203 channel switch determination unit, 204 channel switch control unit, 205 radio control unit

Claims (15)

A communication device that constitutes a network and can communicate with a plurality of other communication devices in the network,
Indicates whether each of the plurality of other communication devices has a function of notifying the communication device that the switching of the channel is completed when the channel used for communication with the communication device is switched. Receiving means for receiving a connection request including information;
Determination means for determining whether the plurality of other communication devices have the function based on the connection request received by the receiving means;
Based on the result of determination by the determination means, switching means for controlling whether to switch the channel being used in communication with the communication device to another channel at the time of the determination,
A communication apparatus comprising:   When the determination unit determines that all of the plurality of other communication devices have the function, the switching unit switches the channel to be used, and the determination unit determines the plurality of other communication devices. 2. The communication apparatus according to claim 1, wherein when it is determined that at least one of the functions does not have the function, the switching unit does not switch the channel to be used.   When the determination unit determines that all of the plurality of other communication devices have the function, the switching unit uses the first signal to channel to the plurality of other communication devices. The communication apparatus according to claim 1, wherein the channel being used is switched to the other channel after notifying that switching is performed.   The communication apparatus according to claim 3, wherein the first signal is an extended channel switch announcement (ECSA) compliant with IEEE802.11. Further comprising radio wave interference in the channel in use or congestion detection means for detecting congestion in the channel in use,
The determination unit determines whether the plurality of other communication devices have the function when the radio wave interference or the congestion is detected by the detection unit. The communication device according to any one of the above.   After switching to the other channel by the switching means, the receiving means is a notification that the switching of the channel has been completed, and information on communication rates that can be handled by the plurality of other communication devices. When the included notification is received from the plurality of other notification devices, the switching unit determines a communication rate with the plurality of other communication devices based on the information of the compatible communication rate. The communication device according to claim 1, wherein the communication device is characterized in that: Radar detection means for detecting radar in the channel in use;
The communication device according to claim 1, wherein the determination unit determines whether the plurality of other communication devices have the function when the radar is detected by the radar detection unit. . Further comprising detecting means for detecting whether or not the communication device is participating in a network different from the network;
In the state where the radar detection unit does not detect the radar and the detection unit detects that the communication device participates in the other network, the determination unit detects the plurality of other 8. The communication apparatus according to claim 7, wherein it is determined whether or not the communication apparatus has the function.   When the determination unit determines that all of the plurality of other communication devices have the function, the switching unit uses the first signal to switch the channel to the plurality of other communication devices. When notifying that switching, the channel being used is switched to the other channel, and when the determination unit determines that at least one of the plurality of other communication devices does not have the function The switching means notifies the communication device having the function of the plurality of other communication devices that the channel is switched using the first signal, and does not have the function. 9, wherein the second signal is used to notify that the channel is to be switched, and then the channel in use is switched to the other channel. The placing of the communication device.   The first signal is an Extended Channel Switch Announcement (ECSA) compliant with IEEE 802.11, and the second signal is a Channel Switch Announcement (CSA) compliant with IEEE 802.11. Item 10. The communication device according to Item 9. A communication device capable of communicating with the other communication device in a network configured by the other communication device,
Transmitting means for transmitting a connection request to the other communication device;
In response to the connection request transmitted by the transmission means, when the channel used for communication with the communication device is switched from the other communication device, the communication device completes notification of switching of the channel. Receiving means for receiving a response including information indicating whether or not it has a function of recognizing a signal of
Determining means for determining whether the other communication device has the function based on the response received by the receiving means;
Determining means for determining a signal to be transmitted after switching of the channel to be used based on a result of determination by the determining means;
A communication apparatus comprising: When the determination unit determines that the other communication device has the function, the determination unit determines to transmit a notification of completion of the channel switching, and the other communication device performs the function. The determination means determines that the connection request is to be transmitted;
The communication apparatus according to claim 11, wherein the channel switching completion notification and the connection request include information on a communication rate that the communication apparatus can handle. A method for controlling a communication device that configures a network and can communicate with a plurality of other communication devices in the network,
Indicates whether each of the plurality of other communication devices has a function of notifying the communication device that the switching of the channel is completed when the channel used for communication with the communication device is switched. A receiving step for receiving a connection request including information;
A determination step of determining whether or not the plurality of other communication devices have the function based on the connection request received in the reception step;
Based on the determination result in the determination step, a switching step for controlling whether or not to switch the channel being used in communication with the communication device to another channel at the time of the determination,
A method for controlling a communication apparatus, comprising: A method of controlling a communication device capable of communicating with the other communication device in a network configured by the other communication device,
A transmission step of transmitting a connection request to the other communication device;
In response to the connection request transmitted in the transmission step, when the channel used for communication with the communication device is switched from the other communication device, a notification of completion of switching of the channel from the communication device is sent. A receiving step of receiving a response including information indicating whether or not it has a function of recognizing a signal;
A determination step of determining whether or not the other communication device has the function based on the response received in the reception step;
A determination step of determining a signal to be transmitted after switching the channel to be used, based on a result of the determination in the determination step;
A method for controlling a communication apparatus, comprising:   A program for causing a computer to function as the communication device according to any one of claims 1 to 12.

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