Communication device, control method, and program product

Abstract

The invention relates to a communication apparatus, a control method, and a program product. A communication device concurrently performs communication with an access point using a first communication interface as a station and communication with another device serving as a client using a second communication interface by a group owner serving as a Wi-Fi direct standard, receiving, from the access point, a first radio frame indicating a change in a frequency channel in use during a time when the first communication interface uses a frequency channel in a predetermined frequency band requiring support of a dynamic frequency selection function, and changing the frequency channels of the first communication interface and the second communication interface on the basis of the first wireless frame if the first communication interface uses the frequency channel in the predetermined frequency band, and the second communication interface uses the same frequency channel as the frequency channel of the first communication interface in the predetermined frequency band.

Description

Technical Field

[0001] This disclosure generally relates to communication devices, control methods, and program products, and particularly to techniques for setting up channels for use in wireless LANs conforming to the IEEE 802.11 series of standards. Background Technology

[0002] Currently, Wireless Local Area Networks (LANs), represented by the IEEE 802.11 series of standards, are widely used. Wireless LANs can utilize various frequency bands, including those that may interfere with other systems such as weather radar and airborne radar. On the other hand, communication devices using frequency bands that may interfere with other systems require a mechanism called Dynamic Frequency Selection (DFS), which switches the used frequency channel to another frequency channel based on the detection of signals from another system. Note that DFS is an abbreviation for Dynamic Frequency Selection. Access points (APs) and stations (STAs) of a wireless LAN cannot use, for example, predetermined frequency channels, such as the 5GHz band W53 or W56, unless these support DFS. Frequency bands such as W53 or W56 that require DFS support will sometimes be referred to as DFS bands below.

[0003] and, The Alliance developed the Wi-Fi Direct (WFD) standard, which defines the process of establishing a communication link between STAs by exchanging communication parameters without the intervention of an Access Point (AP). In the traditional WFD Release 1 (R1), the Group Owner (GO), acting as an AP, could not use channels in the DFS band for WFD communication. However, in WFD Release 2 (R2), if a STA connects to an AP operating in a DFS band channel using a first communication interface (I / F), it is allowed to use the same channel as a GO in another communication I / F. That is, in WFD R2, when a communication device with multiple communication I / Fs connects as a STA to an AP using a channel in the DFS band, it can use the DFS band as a GO by setting its operating channel as that channel. Summary of the Invention

[0004] Japanese Patent Application Publication No. 2013-251926 describes a frequency channel setting method for detecting radar signals in a DFS band in multiple different frequency channels used in multiple communication I / Fs in a communication device. However, as mentioned above, in WFD R2, there is a limitation, for example, if GO uses DFS, then it needs to use the same frequency channel as STA, and an efficient frequency channel setting method that takes these limitations into account has not yet been studied.

[0005] This disclosure provides techniques for appropriately configuring the channels used in a communication apparatus that uses multiple communication interfaces capable of using frequency channels in the DFS band.

[0006] A communication apparatus according to one aspect of this disclosure includes: a communication component capable of performing communication conforming to the IEEE 802.11 standard series using multiple communication interfaces; an acknowledgment component configured to, when communication between a station (STA) and an access point (AP) using a first communication interface and a group owner (GO) using a second communication interface as a client (CL) is performed concurrently, and when a first radio frame indicating a change in the frequency channel in use is received from the AP during a period when the first communication interface uses a frequency channel in a predetermined frequency band requiring support for Dynamic Frequency Selection (DFS) functionality, confirm whether the second communication interface uses the same frequency channel in the predetermined frequency band as the frequency channel of the first communication interface; and a change component configured to, based on the first radio frame, change the frequency channels of the first and second communication interfaces when it is confirmed that the second communication interface uses the same frequency channel in the predetermined frequency band as the frequency channel of the first communication interface.

[0007] According to one aspect of this disclosure, the control method is a control method executed by a communication device capable of performing communications conforming to the IEEE 802.11 standard series using multiple communication interfaces. The control method includes: when communication between a station (STA) and an access point (AP) using a first communication interface and a group owner (GO) using a second communication interface as a client (CL) is performed concurrently, and when a first radio frame indicating a change in the frequency channel in use is received from the AP during a period when the first communication interface uses a frequency channel in a predetermined frequency band requiring support for Dynamic Frequency Selection (DFS) functionality, confirming whether the second communication interface uses the same frequency channel in the predetermined frequency band as the frequency channel of the first communication interface; and when it is confirmed that the second communication interface uses the same frequency channel in the predetermined frequency band as the frequency channel of the first communication interface, changing the frequency channels of the first and second communication interfaces based on the first radio frame.

[0008] The features of this disclosure will become clear from the following description of embodiments with reference to the accompanying drawings. The following description of the embodiments is by way of example. Attached Figure Description

[0009] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present disclosure and, together with the description, serve to explain the principles of the embodiments.

[0010] Figure 1 This is a diagram illustrating an example of system configuration;

[0011] Figure 2 This is a diagram illustrating an example of the hardware configuration of a communication device;

[0012] Figure 3 This is a diagram illustrating an example of the functional configuration of a communication device;

[0013] Figure 4 This is a diagram used to explain the configuration of CSA elements;

[0014] Figure 5 This is a sequence diagram illustrating an example of the communication control process in the system;

[0015] Figure 6 This is a flowchart illustrating an example of a channel change process performed by a communication device;

[0016] Figure 7 This is a sequence diagram illustrating an example of the communication control process in the system;

[0017] Figure 8This is a flowchart illustrating an example of a channel change process performed by a communication device;

[0018] Figure 9 This is a sequence diagram illustrating an example of the communication control process in the system; and

[0019] Figure 10 This is a flowchart illustrating an example of a channel change process performed by a communication device. Detailed Implementation

[0020] In the following, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments are not intended to limit the scope of the claims. Several features are described in the embodiments, but not all such features are required, and several such features can be appropriately combined. Furthermore, in the drawings, the same or similar configurations are given the same reference numerals, and repeated descriptions thereof are omitted.

[0021] (System Configuration)

[0022] Figure 1This is a diagram illustrating an example configuration of a wireless communication system according to this embodiment. The wireless communication system is configured to include an access point (AP 101), an image capture device 102, and an information communication terminal 103, each of which is a communication device. AP 101, image capture device 102, and information communication terminal 103 are configured to perform wireless communication conforming to the IEEE 802.11 standard family (such as the IEEE 802.11bn standard, previous standards defined prior to it, or subsequent standards defined thereafter). Note that IEEE is an abbreviation for the Institute of Electrical and Electronics Engineers. Image capture device 102 is configured to perform communication conforming to the IEEE 802.11 standard family as a station (STA) in a first network 111 formed, for example, by AP 101. Furthermore, image capture device 102 has Wi-Fi Direct (WFD) communication capabilities and is configured to form a second network 112 as a P2P group owner (P2P GO) of WFD. The information communication terminal 103 acts as a WFD P2P client (P2P CL) and connects to the image capture device 102, which acts as a P2P GO, to perform WFD-compliant wireless communication. Note that in the following text, P2P GO will sometimes be simply referred to as GO, and P2P CL will sometimes be simply referred to as CL. In this embodiment, the image capture device 102 concurrently (simultaneously) operates the functions of both STA and GO, connecting to the information communication terminal 103 as GO and simultaneously connecting to the AP 101 as STA. Note that the image capture device 102 can be individually configured with the channel (frequency channel) to be used in the GO and the channel to be used for connecting to the AP 101 as STA. That is, the image capture device 102 can use the same channel for both the GO and STA functions, or it can use different channels. Note that in this embodiment, the image capture device and information communication terminal are shown as examples, but other devices with similar communication functions can be used. For example, a smartphone, tablet, personal computer (PC), camera, etc., can be used instead of the image capture device 102.

[0023] In this embodiment, as described above, the image capture device 102 uses multiple communication interfaces as GOs to form a second network 112 and connects to the information communication terminal 103 operating as a CL, while simultaneously connecting to the AP 101 as a STA. At this time, under the condition that the frequency channel of the Dynamic Frequency Selection (DFS) band is used in the first network 111, the image capture device 102 can also use the DFS band in the second network 112. Note that in this embodiment, the DFS band indicates a predetermined frequency band that requires DFS support, such as W53 or W56, and frequency bands that do not require DFS support will sometimes be referred to as non-DFS bands hereinafter. In this case, the same frequency channel used in the first network 111 needs to be used in the second network 112. Here, if a radar signal is detected in the frequency channel while the AP 101 or the image capture device 102 is connected to the first network 111 using a frequency channel in the DFS band, then the frequency channel in the first network 111 is changed using the DFS function. In this scenario, if the image capture device 102 also uses a frequency channel in the DFS band in the second network 112, then the frequency channel needs to be changed even in the second network 112. That is, if the second network 112 uses a frequency channel in the DFS band, and the channel in the first network 111 changes, then the image capture device 102 needs to change the channel even in the second network 112. On the other hand, if the second network 112 uses a frequency channel outside the DFS band, and the channel in the second network 112 changes according to the channel in the first network 111, then efficiency will decrease due to the unnecessary change in channel usage. In this embodiment, considering this situation, a technique is provided to appropriately configure the channel usage in a communication device using multiple communication interfaces capable of using frequency channels in the DFS band.

[0024] (Device Configuration)

[0025] Figure 2 An example of the hardware configuration of a communication device (AP 101, image capture device 102, or information communication terminal 103) according to this embodiment is shown. Figure 2 As shown, the communication device includes, for example, a storage unit 201, a control unit 202, a functional unit 203, an input unit 204, an output unit 205, a communication unit 206, and an antenna 207 as its hardware configuration.

[0026] Storage unit 201 is configured to include one or more memories, such as ROM and RAM, and to store computer programs configured to perform various operations described later, as well as various information, such as communication parameters for wireless communication. Note that ROM is an abbreviation for Read Only Memory, and RAM is an abbreviation for Random Access Memory. In addition to or in place of memories such as ROM or RAM, storage unit 201 may also include storage media such as floppy disks, hard disks, optical disks, magneto-optical disks, CD-ROMs, CD-Rs, magnetic tapes, non-volatile memory cards, or DVDs. Storage unit 201 may include a solid-state drive (SSD). Furthermore, storage unit 201 may include multiple memories.

[0027] The control unit 202 is formed by one or more processors, such as a CPU and an MPU, and controls the entire communication device by executing a computer program, for example, stored in the storage unit 201. Note that CPU is an abbreviation for Central Processing Unit, and MPU is an abbreviation for Micro Processing Unit. The control unit 202 can be configured to perform processing, in addition to controlling the entire communication device, to generate data or signals (wireless frames) to be transmitted in communication with another communication device. Note that the control unit 202 can be configured to perform processing such as controlling the entire communication device, for example, through the cooperation of a computer program and an operating system (OS) stored in the storage unit 201. Furthermore, the control unit 202 may include multiple processors, such as a multi-core processor, and the processing such as controlling the entire communication device may be performed by multiple processors. Moreover, the control unit 202 can be formed by an application-specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA), etc.

[0028] Furthermore, the control unit 202 controls the functional unit 203 to perform predetermined processes, such as image capture, printing, or projection. The functional unit 203 is hardware used by the communication device to perform the predetermined processes. For example, in the image capture device 102 or the information communication terminal 103, the functional unit 203 may be an image capture unit and perform processing for capturing surrounding images. Moreover, for example, if the communication device is a printer, then the functional unit 203 is a printing unit and performs printing processing on sheets such as paper based on printing data, for example, stored in the storage unit 201 or acquired externally or via wireless communication. Moreover, for example, if the communication device is a projector or smart glasses, then the functional unit 203 is a projection unit and performs projection processing, for example, image data or video data stored in the storage unit 201 or acquired externally or via wireless communication. In the case of smart glasses, the projection surface is the end user's retina, etc. The data to be processed by the functional unit 203 may be data stored in the storage unit 201, or data communicated with another communication device via the communication unit 206, which will be described later. Furthermore, the communication device may provide network storage functionality, such as network attached storage (NAS). This functionality is provided to another communication device as a web service, such as a network storage service. For example, the other communication device connects to the network storage service provided by the communication device using protocols such as SMB (Server Message Block), FTP (File Transfer Protocol), or WebDAV (Web Distributed Authoring and Version Control). This other communication device can then upload files to the storage service or download files from the storage device.

[0029] Input unit 204 receives various operations from the user. Output unit 205 performs various outputs to the user. Here, the output of output unit 205 includes at least one of, for example, a display on the screen, audio output from a speaker, and vibration output. Note that both input unit 204 and output unit 205 can be implemented by a single module (such as a touch panel). Moreover, each of input unit 204 and output unit 205 can be incorporated into a communication device or configured as an external device connected to the communication device.

[0030] Communication unit 206 controls wireless communication conforming to the IEEE 802.11 standard family (such as the IEEE 802.11bn standard or its predecessor or successor standards), or controls Internet Protocol (IP) communication. Communication unit 206, for example, cooperates with antenna 207 to perform wireless frame transmission / reception conforming to the IEEE 802.11 standard family. Note that, for example, the communication unit 206 of each of the image capture device 102 and the information communication terminal 103 can be configured to perform control of wireless communication conforming to the WFD standard. To perform wireless communication conforming to, for example, the IEEE 802.11 standard family or WFD, communication unit 206 can be configured to perform communication in multiple frequency bands (such as sub-GHz band, 2.4GHz band, 5GHz band, 6GHz band, 7GHz band, and 60GHz band). Moreover, communication unit 206 can perform communication using bandwidths of 20GHz, 40MHz, 80MHz, 160MHz, and 320MHz. Furthermore, the communication unit 206 can be configured to operate using, for example, a bandwidth of 240MHz or 4MHz. Note that the image capture device 102 may include, for example, a communication unit 206 configured to communicate with an AP 101 to which it is connected as a STA, and a communication unit 206 configured to communicate with an information communication terminal 103 when the image capture device 102 is used as a GO for WFD. Similarly, the information communication terminal 103 may include a communication unit 206 for WFD and a communication unit 206 for communication with the AP 101. That is, the communication device may include multiple communication units 206 (communication interfaces). Note that one communication unit 206 may provide multiple communication interfaces.

[0031] Antenna 207 is an antenna capable of transmitting / receiving signals in at least one of the following frequency bands: sub-GHz, 2.4GHz, 5GHz, 6GHz, 7GHz, and 60GHz. In this embodiment, one antenna 207 is shown. However, the number of antennas can be two or more. In this example, different antennas can be prepared for each frequency band. Moreover, if multiple antennas are present, the communication device can include multiple communication units 206 corresponding to the multiple antennas.

[0032] Furthermore, in addition to conforming to the IEEE 802.11 standard series and WFD standard, communication unit 206 can also conform to other communication standards, such as NFC, UWB, ZigBee, and MBOA. Note that UWB stands for Ultra Wideband, and MBOA stands for Multi Band OFDM Alliance. NFC stands for Near Field Communication. UWB includes wireless USB, wireless 1394, and WiNET. Furthermore, the communication unit 206 can conform to wired communication standards such as wired LAN. Note that if the communication device supports the aforementioned NFC standards... If the communication standard is a wired communication standard, then a communication unit 206 can be prepared to perform control communication conforming to that communication standard. Note that the communication unit 206 and the antenna 207 can be provided as an integrated component or can be prepared as separate components.

[0033] Next, we will refer to Figure 3 This describes an example of the functional configuration of a communication device (AP 101, image capture device 102, or information communication terminal 103) according to this embodiment. The communication device is configured to include a control processing unit 301, a storage control unit 302, a display unit 303, a first communication unit 304, a second communication unit 305, a CSA element generation unit 306, a channel usage confirmation unit 307, an operation unit 308, and an image capture unit 309 as its functional configuration. Note that CSA is an abbreviation for Channel Switch Announcement. These functions can be implemented, for example, by the control unit 202 executing a program stored in the storage unit 201 or by the processing function unit in the communication unit 206. Note that... Figure 3 This diagram is for explaining the main functions of the communication device according to this embodiment, and other functions are omitted. Therefore, the communication device may of course have functions such as establishing or communicating with a partner device used as a typical AP or STA, as well as functions generally provided in a communication device. Furthermore, Figure 3 Multiple functional blocks can be integrated into one functional block, or one functional block can be divided into multiple functional blocks.

[0034] The control processing unit 301 controls the communication device units according to input signals or programs described later. The control processing unit 301 performs not only internal device control but also control associated with wireless communication. Note that instead of the control processing unit 301 controlling the entire device, multiple hardware units distributing the processing can control the entire device. The storage control unit 302 stores the control program to be executed by the control processing unit 301, as well as communication-related parameters (such as service identifiers (TIDs) and link IDs for identifying one or more links). Various operations, described later, can be implemented by the control processing unit 301 executing the control program stored in the storage control unit 302. The display unit 303 presents information through, for example, text displays for interactive operation and the on / off / blinking of lights. Note that the display unit 303 of the image capture device 102 or the information communication terminal 103 can be configured to, for example, display the viewfinder image during image capture or display captured image data.

[0035] The first communication unit 304 and the second communication unit 305 are wireless communication interfaces for communicating with external devices. The first communication unit 304 and the second communication unit 305 can be configured to perform wireless communication conforming to, for example, the IEEE 802.11 standard family (including the IEEE 802.11bn standard) and the WFD standard. Note that the first communication unit 304 and the second communication unit 305 can be implemented using separate communication units 206, or both can be implemented using a single communication unit 206. In the example, the first communication unit 304 and the second communication unit 305 are configured to perform communication using separate antennas 207. In another example, the first communication unit 304 and the second communication unit 305 can perform communication using a shared antenna by having the ability to separate the signals received through communication, for example, using a filter. Alternatively, a shared antenna can be used by the control processing unit 301 using Dynamic Fast Channel Switching (DRCS) to rapidly switch between the first communication unit 304 and the second communication unit 305. Note that in this embodiment, the image capture device 102 communicates with the AP 101 using the first communication unit 304 and with the information communication terminal 103 using the second communication unit 305. It is important to note that in the following explanation, the AP 101 and the information communication terminal 103 each communicate with the image capture device 102 and can use multiple communication interfaces (such as the first communication unit 304 and the second communication unit 305) to communicate with other devices. Furthermore, the AP 101 and the information communication terminal 103 may each have only one communication interface. Each communication device may have three or more communication interfaces (e.g., a third communication unit (not shown)). In this embodiment, the image capture device 102 operates multiple communication interfaces concurrently (simultaneously) through the first communication unit 304 and the second communication unit 305.

[0036] CSA element generation unit 306 generates Channel Switching Announcement (CSA) elements, which are information elements used by the AP or GO to notify the STA that the channel should be changed. CSA element generation unit 306 sends CSA elements included in beacon frames or probe response frames. CSA elements will be described later.

[0037] The channel confirmation unit 307 performs confirmation regarding the frequency channel in use. For example, when receiving a CSA from AP 101, the image capture device 102 uses the channel confirmation unit 307 to confirm whether the frequency channel used by the image capture device 102 as a P2P GO is the same as the frequency channel used to communicate with AP 101. Furthermore, the channel confirmation unit 307 can confirm whether the frequency channel used by the P2P GO is a frequency channel in the DFS band. In this example, the channel confirmation unit 307 provides the confirmation result to either the first communication unit 304 or the second communication unit 305. Therefore, the first communication unit 304 and the second communication unit 305 can perform channel setting control based on the confirmation result.

[0038] Operation unit 308 is used to accept user operations. Operation unit 308 detects user operations on user interfaces such as a power button for indicating power on / off of the communication device, a release button for indicating image capture, and a replay button for indicating image data playback. Furthermore, if there is an operation component such as a dedicated connection button for initiating communication with another communication device of a communication partner via the first communication unit 304 or the second communication unit 305, then operation unit 308 detects user operations on that operation component. Upon detecting a user operation, operation unit 308 notifies control processing unit 301 of the detection result, and control processing unit 301 controls each functional unit according to the notification. Image capture unit 309 controls, for example, an optical system such as an optical lens unit, aperture / zoom / focus, etc., and an image capture element configured to convert light (video) introduced via the optical lens unit into an electro-video signal. The image capture element may be configured as, for example, a complementary metal-oxide-semiconductor (CMOS) or charge-coupled device (CCD). In this example, image data generated by image capture unit 309 may be transmitted to another communication device via the first communication unit 304 or the second communication unit 305.

[0039] Next, we will refer to Figure 4This describes an example of configuring a Channel Switching Announcement (CSA) element. The CSA element is configured to include an element ID 401, a length 402, a channel switching mode 403, a new channel number 404, and a channel switching count 405. Element ID 401 stores an identifier (ID) indicating that this information element is a CSA. Length 402 stores a value indicating the length of the information element. Channel switching mode 403 stores either 0 or 1 as information indicating restrictions on radio frames until the channel change. If channel switching mode 403 is set to "0", it indicates that there are no restrictions. If channel switching mode 403 is set to "1", it indicates that there is a restriction prohibiting radio frame transmission until the channel change is complete. New channel number 404 stores a value indicating the channel number after the change. Channel switching count 405 stores a value indicating the timing of the channel switch. The value indicating the timing is expressed using a timing term called the Target Beacon Transmission Time (TBTT), which is used by the AP to periodically transmit beacon frames. For example, if "1" is stored in channel switching count 405, it indicates that the channel will switch at the next beacon transmission time. On the other hand, if a "0" is stored in the channel switching count 405, it indicates that the channel will be switched at any time. The CSA element generation unit 306 generates a CSA element with this configuration, and the first communication unit 304 or the second communication unit 305 can transmit the CSA element included in the radio frame.

[0040] (The processing procedure)

[0041] The following will describe an example of the process performed by the wireless communication system according to this embodiment.

[0042] <Processing Example 1>

[0043] Figure 5 This diagram illustrates an example of the communication control process when the channel between the image capture device 102 and the AP 101 changes while the image capture device 102 is concurrently operating multiple communication interfaces. Figure 5 In this configuration, image capture device 102 connects to AP 101 as a STA using a first communication interface, operates as a GO, and connects to information communication terminal 103 using a second communication interface. For example, image capture device 102 connects to AP 101 as a STA using a first communication unit 304, and can concurrently operate as a GO using a second communication unit 305. Here, image capture device 102 uses the same frequency channel in the DFS band in both the first and second communication interfaces.

[0044] In this state, upon detecting a radar signal via DFS (S501), AP 101 begins processing to change the frequency channel in use. AP 101 sends a CSA to the image acquisition device 102 connected as a STA (S502). Here, AP 101 may send a CSA element included in, for example, a beacon frame. Furthermore, upon receiving a search request (detection request) frame from a STA in a disconnected state, AP 101 may send a CSA element included in the detection response frame as a response. Note that AP 101 may also send a CSA element included in another radio frame, such as an action frame. Alternatively, AP 101 may not send a CSA element, but instead send an information element with a different name that stores similar information for channel changes and is included in the radio frame.

[0045] Image capture device 102 receives a radio frame including CSA elements via, for example, a first communication unit 304. Image capture device 102 then controls, for example, a control processing unit 301 to control a channel confirmation unit 307 and confirm the channel in use (S503). For example, image capture device 102 confirms whether a second communication unit 305, operating as a GO, is using the same frequency channel as the first communication unit 304 (before the change). Furthermore, if the second communication unit 305 and the first communication unit 304 are using the same frequency channel, then image capture device 102 confirms whether that frequency channel is a frequency channel in the DFS band. If it is confirmed that the first communication unit 304 and the second communication unit 305 are using the same channel, then image capture device 102 performs processing to change the frequency channel used by the second communication unit 305. That is, image capture device 102 confirms the CSA elements in the radio frame received in S502 (S504). Note that this confirmation can be performed at any time, as long as the frequency channel used as a STA can be changed at an appropriate timing and the frequency channel used as a GO can be changed as needed. For example, confirmation can be performed when a wireless frame is received in S502.

[0046] Image capture device 102 uses CSA element generation unit 306 to generate CSA elements to be transmitted as GO. For example, based on the channel switching count confirmed in S504, image capture device 102 sets the content of the CSA elements to be transmitted (S505). In this example, image capture device 102 first specifies the timing for changing the channel in first communication unit 304 based on the channel switching count confirmed in S504 and the interval of beacon frames transmitted from AP 101. Image capture device 102 then determines the value of the channel switching count to be set in the CSA elements to be transmitted by itself, such that the channel of second communication unit 305 changes timing before the specified timing. That is, in WFD R2, a communication device operating as GO cannot use a frequency channel in the DFS band unless the frequency channel in the DFS band is used by a communication interface different from the communication interface operating as GO. For this reason, image capture device 102 sets the value of the channel switching count such that the frequency channel used as GO changes before or at the latest at the same timing as the frequency channel used as STA. Then, the image capture device 102 sends the CSA, including the channel switching count set in S505, to the information communication terminal 103 (S506) via the second communication unit 305, which serves as the GO. The image capture device 102 sends CSA elements included in radio frames such as beacon frames, probe response frames, or action frames.

[0047] Then, after the second communication unit 305 sends beacon frames as many times as the channel switching count indicated in S505, the image capture device 102 changes the channel used in the second communication unit 305 (S507). The information communication terminal 103 analyzes the CSA element received in S506 and specifies a value for the channel switching count. Then, after waiting until the image capture device 102 sends beacon frames as many times as the count indicated by that value, the information communication terminal 103 changes the channel used to the channel indicated by the CSA element (S508). Note that in S507 and S508, the channel used is changed after the image capture device 102 sends beacon frames as many times as the count set in S505, relative to the timing of CSA transmission in S506 as a reference.

[0048] Subsequently, after sending beacon frames as many times as the channel switching count indicated in the CSA element sent in S502, AP 101 changes the channel in use (S509). Furthermore, after sending beacon frames from AP 101 as many times as the channel switching count indicated in the CSA element confirmed in S504, image capture device 102 changes the channel in use (S510). Note that in S509 and S510, the channel in use is changed after AP 101 sends beacon frames with the same count as specified in the CSA, relative to the timing of the CSA transmission in S502 as referenced.

[0049] Reference Figure 6 An example describing the process performed by the image capture device 102 is provided. Note that the following process can be performed by any communication device having multiple wireless communication interfaces and using a second interface as a GO while connecting to another communication device using a first interface. That is, the image capture device 102 is exemplified, but other communication devices can perform the same process as described below. Note that the following process can be implemented, for example, by the control unit 202 executing a program stored in the storage unit 201, or by the control unit 202 or the communication unit 206 executing a program pre-stored in itself. Note that the functional units performing the processing steps described below are merely examples, and the processing can be performed by other functional units besides these.

[0050] Image capture device 102 receives a radio frame including CSA elements from AP 101 via first communication unit 304 ("Yes" in step S601). First communication unit 304 then notifies control processing unit 301 that CSA has been received. Control processing unit 301 confirms via channel confirmation unit 307 whether the frequency channel used by first communication unit 304 and second communication unit 305 is the same, and whether the frequency channel is a frequency channel in the DFS band (step S602). If first communication unit 304 and second communication unit 305 use different frequency channels or use a frequency channel not in the DFS band ("No" in step S602), then control processing unit 301 performs control to change only the frequency channel of first communication unit 304 (step S607). That is, after the time required for AP 101 to send beacon frames the same number of times as the channel switching count indicated in step S601 has elapsed, control processing unit 301 performs control to change the channel of first communication unit 304 (step S607).

[0051] If the first communication unit 304 and the second communication unit 305 use the same frequency channel in the DFS band ("Yes" in step S602), then the control processing unit 301 sets the channel switching count via the CSA element generation unit 306 (step S603). The value to be set here can be determined based on the channel switching count included in the CSA element of the radio frame obtained in step S601 and the beacon frame transmission interval of AP 101 and image capture device 102 GO. That is, the timing for the first communication unit 304 to change the channel is first specified, and the channel switching count is set such that the channel of the second communication unit 305 is changed before the specified timing. If the channel switching count is set, then the control processing unit 301 decides to set the second communication unit 305, which is operating as GO, to the same channel as the channel of the first communication unit 304 after the change (S604). Note that this is just an example, and as will be described later, the second communication unit 305 can use a different channel than the channel of the first communication unit 304 after the change. However, if the second communication unit 305 uses a different channel than the first communication unit 304, then the second communication unit 305 cannot use the channel in the DFS band. On the other hand, if the second communication unit 305 uses the same channel as the modified first communication unit 304 and the first communication unit 304 uses a channel in the DFS band that is different from the channel before the modification, then the second communication unit 305 can use the channel in the DFS band.

[0052] Control processing unit 301 sends a radio frame including a CSA element storing the channel switching count set in step S603 to information communication terminal 103 via second communication unit 305 (step S605). Control processing unit 301 controls second communication unit 305 to change the channel after sending beacon frames a number of times equal to the channel switching count set in step S603 (step S606). Thereafter, after the time required for AP 101 to send beacon frames a number of times equal to the channel switching count indication obtained in step S601 has elapsed, control processing unit 301 executes control to change the channel of first communication unit 304 (step S607).

[0053] As described above, in this processing example, the image capture device 102, which concurrently operates multiple communication interfaces for the STA and P2P GO, determines whether to change the channel of the P2P GO based on the CSA received from the AP 101. For example, if the STA and P2P GO use the same frequency channel in the DFS band, then when the state indicating that the frequency channel should be changed is set, the image capture device 102 also changes the frequency channel of the GO. At this time, the image capture device 102 controls the timing of changing the frequency channel of the GO, such that the change of the GO's frequency channel is completed at the timing of changing the frequency channel of the STA. This prevents the image capture device 102 from obtaining the state that the GO is using a frequency channel in the DFS band during periods when the STA is not using a frequency channel in the DFS band. Moreover, if the STA and P2P GO use different frequency channels or use frequency channels outside the DFS band, then the image capture device 102 changes only the frequency channel of the STA based on the CSA received from the AP 101. That is, in this case, the image capture device 102 can prohibit the change of the GO's frequency channel. This prevents unnecessary channel changes and prevents a decrease in communication efficiency in the GO.

[0054] <Processing Example 2>

[0055] It can be assumed that if the image capture device 102 receives CSA as a STA, and the STA uses a frequency channel in the same DFS band as the GO, then the changed frequency channel of the STA, indicated by the new channel number of the CSA, is a frequency channel in the DFS band. In this case, the image capture device 102 can set the frequency channel of the GO to be the same as that of the STA. However, in this case, if a radar signal is detected through the changed channel in the DFS band, then a channel change is required again. Therefore, in this case, the image capture device 102 can set the channel so that the GO uses a frequency channel outside the DFS band. In this processing example, reference will be made to... Figure 7 and Figure 8 An example describing the process in this situation. Figure 7 It is a sequence diagram illustrating an example of the communication control process in a wireless communication system, and Figure 8 This is a flowchart illustrating an example of the processing performed by the image capture device 102.

[0056] Figure 7 S701 to S705 and Figure 5 S501 to S505 are the same, and Figure 8 Steps S801 to S803 in the process Figure 6Steps S601 to S603 are the same and their description will be omitted. In this processing example, the image capture device 102 confirms whether the channel of the changed STA, indicated by the new channel number of the CSA element confirmed in S704 or step S801, is a channel in the DFS band (S706 or step S804). If it is confirmed that the channel of the changed STA is a channel in the DFS band ("Yes" in step S804), then the image capture device 102 sets the channel of the changed GO to a frequency channel in a non-DFS band (S707 and step S809). That is, in this case, the image capture device 102 changes the channel of the GO to a channel different from the channel of the STA. The image capture device 102 stores the value of the frequency channel set in S707 in the new channel number and generates a CSA element that stores the channel switching count set in S705. The image capture device 102 then transmits the radio frames (beacon frames, probe response frames, action frames, etc.) including the generated CSA elements to the information communication terminal 103 (S708 and step S806). The subsequent processing of steps S709 to S712 and steps S807 and S808... Figure 5 S507 to S510 and Figure 6 Steps S606 and S607 are the same, and their descriptions will be omitted. Note that if it is confirmed that the changed STA channel is a channel outside the DFS band ("No" in step S804), then... Figure 6 As in step S604, the image capture device 102 can change the channel of the GO to the same channel as the changed channel of the STA (step S805). Note that this is merely an example, and if the channel of the STA changes from a channel in the DFS band, then regardless of the destination of the change, the image capture device 102 can change the channel of the GO to a different channel than the channel of the STA. The subsequent processing in steps S806 to S808 is similar to... Figure 6 Steps S605 to S607 are the same, and their descriptions will be omitted.

[0057] As described above, in this processing example, the channel used by the GO is prohibited from changing from a frequency channel in the DFS band to another frequency channel in the DFS band. This prevents the channel from being changed again based on the detection of radar signals in the changed channel, and prevents efficiency from decreasing due to frequent channel changes. Moreover, for example, if the frequency channel of the STA after the change is a channel in the DFS band, if the GO's frequency channel moves to that channel first, then there will be a period in which the GO uses a frequency channel in the DFS band that is different from the channel used by the STA. That is, frequency channels that are not allowed in WFD R2 can be set. For this reason, if the frequency channel of the STA after the change is a frequency channel in the DFS band and the GO uses the same channel as the STA, then the GO needs to change its channel after waiting for the STA's frequency channel change to be completed. On the other hand, in this processing example, if the frequency channel of the STA after the change is a frequency channel in the DFS band, then the GO's frequency channel is changed to a channel outside the DFS band. Therefore, the frequency channel of the GO can be changed without waiting for the frequency channel of the STA to complete, and in particular, if the load in the GO is high, it can prevent the period during which the GO cannot perform data communication from becoming longer.

[0058] <Processing Example 3>

[0059] This processing example describes a scenario where the frequency channel of the STA before and after the change is a frequency channel in the DFS band, and the GO uses the same channel as the STA. In this processing example, in the image capture apparatus 102, the channel in the DFS band after the change is also indicated by the new channel number of the CSA received by the STA using the same frequency channel in the DFS band as the GO's frequency channel. This processing example will refer to... Figure 9 and Figure 10 This describes the processing performed when the image capture device 102 sets the frequency channel of the GO to a channel in the same DFS band as the channel of the STA. Figure 9 It is a sequence diagram illustrating an example of the communication control process in a wireless communication system, and Figure 10 This is a flowchart illustrating an example of the processing performed by the image capture device 102.

[0060] Figure 9 S901 to S906 and Figure 7 S701 to S706 are the same, and Figure 10 Steps S1001 to S1004 in the process Figure 8Steps S801 to S804 are the same, and their description will be omitted. Note that if it is confirmed that the frequency channel of the changed STA is not a channel in the DFS band (the frequency channel is a channel outside the DFS band) (No in step S1004), then the image capture device 102 performs the same operation as... Figure 8 The same processes as in steps S805 to S808 (steps S1005 to S1008) are applied. These processes are the same as those described above, and their description will not be repeated here.

[0061] On the other hand, if it is confirmed that the frequency channel of the STA after the change is a channel in the DFS band ("Yes" in step S1004), then the image capture device 102 begins processing for using the channel in the DFS band even in the GO. If the frequency channel of the GO after the change is a channel in the DFS band, then the image capture device 102 needs to prevent the GO's channel from being changed before the frequency channel of the STA is changed. Moreover, after the frequency channel of the STA is changed, the image capture device 102 is not allowed to continue using the channel in the DFS band before the change in the GO. For this reason, in this processing example, the image capture device 102 controls the second communication unit 305 through the control processing unit 301, thereby disconnecting the GO from the information communication terminal 103 and stopping its function as the GO (S907 and S908, and step S1009). Then, the image capture device 102 controls the first communication unit 304 via the control processing unit 301, thereby changing the channel used by the STA to the channel indicated by the new channel number confirmed in step S906 or S1001 (S910 and S1010). Similarly, the channel used by the AP 101 is also changed (S909). Note that the timing of changing the channel used by the STA function of the AP 101 and the image capture device 102 is the same as in the other processing examples described above.

[0062] Subsequently, the image capture device 102 controls the second communication unit 305 via the control processing unit 301, thereby reactivating its function as a GO and setting the GO's usage channel to use the same channel as the STA (S911 and step S1011). Then, the image capture device 102 controls the second communication unit 305 via the control processing unit 301, thereby connecting to the P2P CL using the changed channel (S912 and step S1012). Note that, for example, when the connection with the information communication terminal 103 is disconnected, the image capture device 102 can notify the information communication terminal 103 of the information indicating the changed channel. Moreover, for example, after reactivating the GO function, the image capture device 102 can send the information indicating the changed usage channel to the information communication terminal 103 using a beacon frame or a probe response frame.

[0063] As described above, in this processing example, in order to change the channel used by the GO from a frequency channel in the DFS band to another frequency channel in the DFS band, the image capture device 102 temporarily suspends its operation as the GO, and after the STA's channel is changed, the GO is reactivated using the changed channel. This prevents the GO from using a channel in the DFS band that is different from the channel used by the STA. This facilitates the management of the used channels in the image capture device 102. Especially when communication as the GO is allowed to be interrupted for a predetermined period of time, if the GO and STA use the same frequency channel, the used channels in the image capture device 102 can be managed efficiently without significantly reducing communication efficiency. Note that, as an example, the image capture device 102 can determine whether to allow the use of a channel in the DFS band as the GO's frequency channel based on, for example, the size of the communication load on the GO. Furthermore, it can determine whether to allow the use of a channel in the DFS band as the GO's frequency channel based on another criterion.

[0064] As described above, according to this embodiment, a communication device such as the image capture device 102, which uses multiple communication interfaces capable of using frequency channels in the DFS band, can be appropriately configured to use the channels.

[0065] Other embodiments

[0066] The embodiments of this disclosure can also be implemented by a computer that reads and executes computer-executable instructions (e.g., one or more programs) recorded on a storage medium (which may also be more fully referred to as a 'non-transitory computer-readable storage medium') to perform one or more functions of the above embodiments and / or includes one or more circuits (e.g., application-specific integrated circuits (ASICs)) for performing one or more functions of the above embodiments, and by a method performed by a computer of a system or device by, for example, reading and executing computer-executable instructions from the storage medium to perform one or more functions of the above embodiments and / or controlling one or more circuits to perform one or more functions of the above embodiments. The computer may include one or more processors (e.g., a central processing unit (CPU), a microprocessor unit (MPU)) and may include separate computers or networks of separate processors to read and execute computer-executable instructions. The computer-executable instructions may be provided to the computer, for example, from a network or storage medium. The storage medium may include, for example, a hard disk, random access memory (RAM), read-only memory (ROM), storage devices for distributed computing systems, optical discs (such as CDs, DVDs, or Blu-ray discs). TM One or more of the following: flash memory devices, memory cards, etc.

[0067] Embodiments of the present invention can also be implemented by providing software (including computer program products of computer programs) that performs the functions of the above embodiments to a system or device via a network or various storage media, and the computer (central processing unit (CPU) or microprocessor unit (MPU) of the system or device) reads and executes the computer program.

[0068] Various embodiments have been described in detail above, but it will be understood that this disclosure is not limited to these embodiments and covers all modifications, variations, substitutions and equivalents that fall within the scope of the appended claims.

Claims

1. A communication device, comprising: A communication component capable of performing communications conforming to the IEEE 802.11 standard series using multiple communication interfaces; The verification component is configured to verify whether the second communication interface uses the same frequency channel in the predetermined frequency band as the frequency channel of the first communication interface when communication between a station (STA) and an access point (AP) using a first communication interface as a Wi-Fi Direct (WFD) standard and a group owner (GO) and another device acting as a client (CL) are performed concurrently, and when the first communication interface uses a frequency channel in a predetermined frequency band that requires support for Dynamic Frequency Selection (DFS) functionality, and a first radio frame indicating a change in the frequency channel in use is received from the AP during the period when the first communication interface uses a frequency channel in a predetermined frequency band that requires support for Dynamic Frequency Selection (DFS) functionality. as well as A changing component is configured to change the frequency channels of the first communication interface and the second communication interface based on the first radio frame, provided that the second communication interface uses the same frequency channel in the predetermined frequency band as the frequency channel of the first communication interface.

2. The apparatus according to claim 1, wherein If the frequency channel of the first communication interface after modification is a frequency channel in a frequency band that does not require DFS function support, the modification component is configured to change the frequency channel of the second communication interface to the same frequency channel as the frequency channel of the first communication interface after modification.

3. The apparatus according to claim 1, wherein If the frequency channel of the first communication interface after modification is a frequency channel in a frequency band that requires DFS function support, the modification component is configured to change the frequency channel of the second communication interface to a frequency channel in a frequency band that is different from the frequency channel of the first communication interface after modification and does not require DFS function support.

4. The apparatus according to claim 1, wherein The changing component is configured to change the frequency channel of the second communication interface before the timing specified in the first radio frame for changing the frequency channel of the first communication interface.

5. The apparatus according to claim 1, wherein The changing component is configured to send a second radio frame to the other device used as CL, the second radio frame including timing instructions for changing the frequency channel of the second communication interface and information about the frequency channel of the second communication interface after the change.

6. The apparatus according to claim 5, wherein The second radio frame is one of a beacon frame, a probe response frame, and an action frame that includes a Channel Switching Announcement (CSA) element.

7. The apparatus according to claim 6, wherein The changing component is configured to change the frequency channel of the second communication interface when transmitting beacon frames as a predetermined count as a GO, and to transmit the second radio frame to the other device, in which the predetermined count is stored as a channel switching count value of a CSA element.

8. The apparatus according to claim 6, wherein The alteration component is configured to send the second radio frame to the other device, wherein the frequency channel of the second communication interface after the alteration is stored as a value of the new channel number of the CSA element in the second radio frame.

9. The apparatus according to claim 1, wherein If the frequency channel of the first communication interface after the change is a frequency channel in a frequency band that requires DFS function support, the changing component is configured to stop the function as GO by disconnecting the connection of the second communication interface to the other device used as CL, and after the frequency channel of the first communication interface is changed, to reactivate the function as GO using the same frequency channel as the changed first communication interface, and to connect to the other device.

10. The apparatus according to any one of claims 1 to 9, wherein The first radio frame is one of a beacon frame, a probe response frame, and an action frame that includes a Channel Switching Announcement (CSA) element.

11. The apparatus of claim 10, wherein After the first radio frame is received, the changing component is configured to change the frequency channel of the first communication interface according to the elapsed time period of the beacon frames sent by the AP as many times as the channel switching count indicated by the value in the CSA element of the first radio frame.

12. The apparatus of claim 10, wherein The changing component is configured to change the frequency channel of the first communication interface to the frequency channel specified by the value of the new channel number of the CSA element of the first radio frame.

13. The apparatus according to claim 1, wherein If it is confirmed that the second communication interface uses a frequency channel different from the frequency channel of the first communication interface, or if it is confirmed that the second communication interface uses a frequency channel that is the same as the frequency channel of the first communication interface but in a frequency band different from the predetermined frequency band, the changing component is configured to change the frequency channel of the first communication interface without changing the frequency channel of the second communication interface based on the first radio frame.

14. A control method executed by a communication device, said communication device being capable of performing communication conforming to the IEEE 802.11 standard series using multiple communication interfaces, said control method comprising: When communication between a station (STA) and an access point (AP) using a first communication interface and a group owner (GO) using a second communication interface as a Wi-Fi Direct (WFD) standard is performed concurrently, and when a first radio frame indicating a change in the frequency channel in use is received from the AP during the time when the first communication interface uses a frequency channel in a predetermined frequency band that requires support for Dynamic Frequency Selection (DFS) functionality, it is confirmed whether the second communication interface uses the same frequency channel in the predetermined frequency band as the frequency channel of the first communication interface. as well as If it is confirmed that the second communication interface uses the same frequency channel in the predetermined frequency band as the first communication interface, the frequency channels of the first communication interface and the second communication interface are changed based on the first radio frame.

15. A computer program product comprising instructions that, when executed by a computer, cause the computer to perform the control method of claim 14.

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