Communication device, communication method, and program

Abstract

To provide a communication device, a communication method, and a program that reduce a decrease in throughput after roaming.SOLUTION: A communication device includes acquisition means for acquiring information on a plurality of access points of mutually different frequency bands, change means for changing roaming conditions for executing roaming by comparing a currently connected frequency band with a roaming target frequency band, and execution means for executing roaming when a signal of the currently connected frequency band satisfies the roaming conditions.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a communication device, a communication method, and a program. [Background technology]

[0002] Roaming, in which a communication device switches connections between access points (hereinafter referred to as APs) with the same SSID, is a conventionally known technique. Roaming has set conditions for activating the function. For example, roaming is performed when either the signal-to-noise ratio (hereinafter referred to as SNR) or radio wave strength (hereinafter referred to as RSSI: Received Signal Strength Indicator) deteriorates and falls below a certain threshold. SNR is the ratio of signal to noise; a high SNR indicates a state in which the influence of noise is small and the signal is strong, while a low SNR indicates a state in which the influence of noise is large and the signal is weak. RSSI indicates the strength of the radio wave; a high RSSI indicates a state in which the signal is strong, and a low RSSI indicates a state in which the signal is weak.

[0003] Patent document 1 discloses a method in which a band having a high priority is scanned that is the same as the band of the channel of the currently connected AP, and if there is no AP to roam to based on the scan results, a band different from the band of the currently connected channel is scanned.

[0004] Patent document 2 discloses a method of reading out roaming start conditions that correspond to the location information of a mobile body, direction information indicating the direction in which the mobile body will approach the position indicated by the location information, and a radio wave intensity threshold, and setting the radio wave intensity threshold based on the detected value of the location information of the mobile body and the detected value of the direction information of the mobile body. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2014-232977 [Patent Document 2] Japanese Patent Application Publication No. 2023-72130 Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the conventional technology disclosed in the above-mentioned patent document, when the frequency band of the currently connected AP is different from the frequency band of the roaming destination AP, the throughput after roaming may decrease. This is because the throughput generally differs depending on the frequency band.

[0007] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a communication device, a communication method, and a program that reduce the decrease in throughput after roaming. [Means for solving the problem]

[0008] In order to solve this problem, for example, a communication device of the present invention has the following configuration: an acquisition means for acquiring information on a plurality of access points in different frequency bands; Connected frequency band than Roaming frequency bands If is large, Set the roaming conditions for roaming. relief and a modifying means for modifying the an execution means for executing roaming when a signal of a frequency band currently being connected satisfies the roaming condition; A communication device comprising: [Effects of the Invention]

[0009] According to the present invention, it is possible to reduce the decrease in throughput after roaming. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram showing the configuration of a digital camera according to an embodiment. [Figure 2] FIG. 2 is an external view showing a display screen of the digital camera according to the embodiment. [Figure 3] FIG. 1 is a diagram showing the configuration of a system including a digital camera according to an embodiment. [Figure 4] FIG. 4 is a sequence diagram showing processing between the digital camera and AP according to the first embodiment. [Figure 5] 5 is a flowchart showing processing of the digital camera according to the first embodiment. [Figure 6] FIG. 10 is a sequence diagram showing processing between a digital camera and an AP according to the second embodiment. [Figure 7] 10 is a flowchart showing processing of a digital camera according to a second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the scope of the claimed invention. Although multiple features are described in the embodiments, not all of these multiple features are necessarily essential to the invention, and multiple features may be combined arbitrarily. Furthermore, in the accompanying drawings, the same reference numerals are used to designate the same or similar components, and redundant explanations will be omitted.

[0012] <Digital camera configuration> First, the configuration and functions of a digital camera 100 according to this embodiment will be described with reference to Fig. 1. Fig. 1 is a diagram showing the configuration of a digital camera according to this embodiment. Specifically, Fig. 1(a) is a block diagram showing the hardware configuration of the digital camera 100. Fig. 1(b) is a front oblique view of the digital camera 100. Fig. 1(c) is a rear oblique view of the digital camera 100.

[0013] In this embodiment, a digital camera capable of capturing still images, moving images, and other images (hereinafter referred to as images) will be described as an example of a communication device, but the present embodiment is not limited to digital cameras. For example, the communication device may be an information processing device such as a tablet device or personal computer with a camera function, a surveillance camera, or a medical camera. The digital camera 100 includes a control unit 101, an imaging unit 102, a nonvolatile memory 103, a working memory 104, an operation unit 105, a display unit 106, a recording medium 107, and a connection unit 108.

[0014] The control unit 101 is an arithmetic processing unit that controls the entire digital camera 100. The control unit 101 executes programs stored in a nonvolatile memory 103, which will be described later, to perform various processes, such as communication processes and control processes, which will be described later. The control unit 101 has, for example, a CPU (Central Processing Unit). Instead of or in addition to the CPU, the control unit 101 may have other processors, such as an MPU (Micro Processing Unit), a GPU (Graphics Processing Unit), or a QPU (Quantum Processing Unit). Note that, instead of the control unit 101 controlling the entire device, one or more pieces of hardware, such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array), may share processing tasks to control part or the entire device.

[0015] The control unit 101 reads a program stored in the nonvolatile memory 103, thereby realizing the functions of, for example, an acquisition unit, a change unit, and an execution unit. Specifically, the control unit 101 acquires information on a plurality of access points (hereinafter, APs) of different frequency bands via the connection unit 108. The control unit 101 compares the currently connected frequency band with the frequency band to be roamed, and changes the roaming conditions for executing roaming. The control unit 101 executes roaming when the signal of the currently connected frequency band satisfies the roaming conditions. The processing by the control unit 101 will be described in more detail below.

[0016] The imaging unit 102 includes a group of lenses including a zoom lens and a focus lens, and a shutter with an aperture function. The imaging unit 102 also includes an imaging element configured with a CCD (Charge Coupled Device) and a CMOS (Complementary Metal-Oxide-Semiconductor) element that converts a subject image into an electrical signal, and an A / D converter that converts an analog image signal output from the imaging element into a digital signal. Under the control of the control unit 101, the imaging unit 102 converts subject image light formed by a lens included in the imaging unit 102 into an electrical signal using the imaging element, performs noise reduction processing, and outputs image data consisting of a digital signal. The image data output from the imaging unit 102 is recorded, for example, on a recording medium 107.

[0017] The nonvolatile memory 103 is an electrically erasable and recordable memory, and may be, for example, an EEPROM (Electrically Erasable Programmable Read-Only Memory). Constants, programs, etc. for the operation of the control unit 101 are recorded in the nonvolatile memory 103. The programs referred to here are programs for executing communication processing and control processing, which will be described later in this embodiment.

[0018] The working memory 104 temporarily stores programs and data. The working memory 104 is, for example, a RAM (Random Access Memory). The working memory 104 is used as a working area for storing constants and variables for the operation of the control unit 101, and for expanding programs read from the non-volatile memory 103. The working memory 104 is also used as a buffer memory for temporarily storing image data captured by the imaging unit 102, and as an image display memory for the display unit 106.

[0019] The operation unit 105 has operation members such as various switches, buttons, and a touch panel that accept various operations from the user. For example, as shown in FIGS. 1(b) and 1(c), the operation unit 105 includes a shutter button 105a, a playback button 105b, a four-way key 105c, and a touch panel 105d. The shutter button 105a accepts operations related to photographing a subject. The playback button 105b accepts operations related to playing back a captured image. The four-way key 105c has up, down, left, and right buttons and accepts operations related to various camera settings. The touch panel 105d is formed integrally with the display unit 106 and accepts various operations.

[0020] The shutter button 105a is turned on during operation by being pressed halfway (a shooting preparation instruction), and a first shutter switch signal is generated. When the control unit 101 receives the first shutter switch signal, it controls the imaging unit 102 to start one of processes including AF (autofocus) processing, AE (auto exposure) processing, AWB (auto white balance) processing, and EF (pre-flash) processing. When the operation is completed, the shutter button 105a is pressed all the way (a shooting instruction), and a second shutter switch signal is generated. When the control unit 101 receives the second shutter switch signal, it starts a series of shooting processes from reading out the signal from the imaging unit 102 to writing image data to the recording medium 107.

[0021] The display unit 106 displays the viewfinder image during shooting, displays the captured image, and displays text for interactive operation. The display unit 106 is, for example, a display device such as a liquid crystal display or an organic EL display. The display unit 106 may be integrated with the digital camera 100 or may be an external device connected to the digital camera 100. The digital camera 100 only needs to be able to connect to the display unit 106 and have a function for controlling the display on the display unit 106.

[0022] The recording medium 107 records the image data output from the imaging unit 102 as an image file. The control unit 101 reads out the image file recorded on the recording medium 107. The recording medium 107 may be a memory card or a hard disk drive that is attached to the digital camera 100, or may be a flash memory or a hard disk drive that is built into the digital camera 100. It is sufficient for the digital camera 100 to have at least a means for accessing the recording medium 107.

[0023] The connection unit 108 is an interface for connecting to an external device so as to be able to communicate with the external device. The digital camera 100 of this embodiment can exchange data with the external device via the connection unit 108. For example, the digital camera 100 transmits image data output from the imaging unit 102 to the external device via the connection unit 108. The digital camera 100 can receive control instructions output from the external device via the connection unit 108. In this embodiment, the connection unit 108 includes an interface for communicating with the external device via a wireless LAN in accordance with the IEEE802.11 standard. The control unit 101 controls the connection unit 108 to achieve wireless communication with the external device.

[0024] <Digital camera display screen> Next, the display screen of the digital camera 100 of this embodiment will be described with reference to Fig. 2. Fig. 2 shows the display screen of the digital camera. Fig. 2(a) is a diagram of a setting screen for setting up communication. Fig. 2(b) is a diagram of a selection screen for selecting a network. Fig. 2(c) is a diagram of a completion screen indicating completion of connection.

[0025] 2(a), the setting screen 200 includes a new setting button 201, a cancel button 202, and an OK button 203. The setting screen 200 is a screen for setting a connection with an external device such as an AP. The setting screen 200 is displayed on the display unit 106 of the digital camera 100.

[0026] The new setting button 201 is a button for the control unit 101 to start a connection with an external device such as an AP.

[0027] A cancel button 202 is a button for the control unit 101 to cancel a connection with an external device such as an AP.

[0028] The OK button 203 is a button for confirming the operation of the digital camera 100. When the OK button 203 is selected by the user while the New Setting button 201 is selected, the control unit 101 performs an AP scan. In this scan, the control unit 101 attempts to wirelessly receive a signal including the SSID and BSSID from each of one or more APs.

[0029] 2(b), the selection screen 210 includes a connect button 211, a connect button 212, and a cancel button 213. The selection screen 210 is a screen for selecting an external device, such as an AP, to connect to. The selection screen 210 is displayed on the display unit 106 of the digital camera 100.

[0030] The connect button 211 is a button that the user uses to select an AP to connect the digital camera 100. When the connect button 211 is selected, the control unit 101 attempts to connect to the AP based on the displayed SSID and channel. For example, when the connect button 211 is selected, the control unit 101 attempts to connect to an AP whose SSID is "Conon" and whose channel is "1ch."

[0031] The connect button 212 is a button that allows the user to select an AP to connect the digital camera 100 to. When the connect button 211 is selected, the control unit 101 attempts to connect to the AP based on the displayed SSID and channel. For example, when the connect button 212 is selected, the control unit 101 attempts to connect to an AP whose SSID is "Conon" and whose channel is "36ch."

[0032] The cancel button 213 is a button that the user can use to cancel the connection between the digital camera 100 and an external device such as an AP.

[0033] 2(c), the completion screen 220 includes an OK button 221. The completion screen 220 is a screen that is displayed when the connection between the digital camera 100 and an external device such as an AP is completed. The completion screen 220 is displayed on the display unit 106 of the digital camera 100.

[0034] The OK button 221 is a button that the digital camera 100 presses to confirm that the external device has been connected.

[0035] <System configuration including a digital camera> Next, a system configuration including the digital camera 100 of this embodiment will be described with reference to Fig. 3. Fig. 3 is a diagram showing the system configuration including the digital camera 100. The system has the digital camera 100 and APs 301 and 302, which are external devices and function as access points.

[0036] The digital camera 100 is set to be able to connect to APs 301 and 302 with the SSID "Conon."

[0037] AP301 has the SSID set to "Conon" and the frequency band set to "2.4GHz."

[0038] The SSID of AP302 is set to “Conon” and the frequency band is set to “6 GHz.” In other words, the frequency band of AP301 is different from the frequency band of AP302.

[0039] (First embodiment) Hereinafter, the roaming method according to the first embodiment will be described with reference to FIGS.

[0040] <Digital camera control sequence> The control sequence of the digital camera 100 of the first embodiment will be described with reference to Fig. 4. Fig. 4 is a sequence diagram showing the processing between the digital camera of the first embodiment and the AP.

[0041] In S401, the control unit 101 of the digital camera 100 receives a connection start instruction from the user via the operation unit 105. For example, with the setting screen 200 displayed on the display unit 106 as shown in FIG. 2(a), the control unit 101 receives the user's selection of the new setting button 201, and then receives input of the OK button 203. As a result, the control unit 101 determines that the connection start instruction has been received.

[0042] In S402, the control unit 101 of the digital camera 100 scans to attempt wireless reception of a signal including the SSID and BSSID from each of one or more APs.

[0043] In S403, the control unit 101 of the digital camera 100 receives a connection AP selection instruction from the user via the operation unit 105. For example, the control unit 101 receives input from the connection button 211 while displaying the selection screen 210 on the display unit 106 as shown in FIG.

[0044] In S404, the control unit 101 of the digital camera 100 associates the SSID and channel of the AP corresponding to the connection AP selection instruction received in S403 as connection settings for the SSID and channel of the desired AP, and stores them in the working memory 104.

[0045] In S405, the control unit 101 of the digital camera 100 transmits a connection request to the AP to which the connection attempt is being made in order to perform connection processing in cooperation with that AP.

[0046] In S406, the control unit 101 of the digital camera 100 receives a connection OK notification from the AP to which the connection attempt is being attempted.

[0047] In S407, the control unit 101 of the digital camera 100 determines that the AP to which the connection attempt is being made is the desired AP, and establishes a wireless LAN connection with this AP. After establishing the wireless LAN connection, the control unit 101 displays a completion screen 220 on the display unit 106, as shown in FIG. 2(c), for example, and accepts input of an OK button 221 from the user. The control unit 101 transmits a notification of connection completion to the AP, and receives a notification of connection completion from the AP.

[0048] In S408, when the control unit 101 of the digital camera 100 determines that the SNR of the currently connected AP (hereinafter referred to as the connected AP) has fallen below the SNR threshold, it specifies and scans an AP with a desired SSID stored in the work memory 104. In the scan, the control unit 101 acquires the frequency band of the connected AP and the frequency band of the roaming target AP. Note that in this embodiment, the control unit 101 acquires the frequency band of the connected AP in S408, but it is also possible to acquire it in S407, which is the timing of connecting to the connected AP.

[0049] In S409, the control unit 101 of the digital camera 100 determines whether the frequency band of the connected AP and the frequency band of the roaming target AP are different. If the control unit 101 determines that they are different, it changes the SNR threshold as the SNR condition, which is a roaming condition. For example, if the frequency band of the connected AP is "2.4 GHz" and the frequency band of the roaming target AP is "6 GHz," the control unit 101 determines that the frequency band of the roaming target AP is greater than the frequency band of the connected AP and changes the SNR condition, which is a roaming condition, i.e., the SNR threshold, from the originally set "15" to "20." In other words, if the frequency band of the roaming target AP is greater than the frequency band of the connected AP, the control unit 101 relaxes the roaming condition to make roaming easier. Furthermore, when the frequency band of the connected AP is "6 GHz" and the frequency band of the roaming target AP is "2.4 GHz," the control unit 101 determines that the frequency band of the roaming target AP is smaller than the frequency band of the connected AP, and changes the SNR condition, which is a roaming condition, i.e., the SNR threshold, from the originally set "15" to "10." In other words, when the frequency band of the roaming target AP is smaller than the frequency band of the connected AP, the control unit 101 tightens the roaming condition, making roaming more difficult.

[0050] In S410, when the control unit 101 of the digital camera 100 determines that the SNR of the connecting AP is below the SNR threshold and that the roaming conditions are met, it sends a connection request to the AP to which the connection attempt is being made in order to perform connection processing in cooperation with the AP.

[0051] In S411, the control unit 101 of the digital camera 100 receives a connection OK notification from the AP to which the connection is attempted.

[0052] In S412, the control unit 101 of the digital camera 100 determines that the AP to which the connection attempt is being made is the desired AP, and establishes a wireless LAN connection with this AP. After establishing the wireless LAN connection, the control unit 101 transmits a connection completion notification to the AP, and receives a connection completion notification from the AP.

[0053] <Digital camera control flow> The control flow of the digital camera 100 of the first embodiment will be described with reference to Fig. 5. Fig. 5 is a flowchart showing the processing of the digital camera of the first embodiment.

[0054] In S501, the control unit 101 of the digital camera 100 determines whether a connection start instruction has been received from the user. If the control unit 101 determines that a connection start instruction has been received, the process proceeds to S502. If the control unit 101 determines that a connection start instruction has not been received, the process of S501 is repeated. The process of S501 corresponds to S401 in FIG. 4.

[0055] In S502, the control unit 101 of the digital camera 100 scans to attempt wireless reception of a signal including the SSID and BSSID from each of one or more APs. The processing of S502 corresponds to S402 in FIG.

[0056] In S503, the control unit 101 of the digital camera 100 determines whether a connection AP selection instruction has been received. If the control unit 101 determines that a connection AP selection instruction has been received, the process proceeds to S504. If the control unit 101 determines that a connection AP selection instruction has not been received, the process of S503 is repeated.

[0057] In S504, the control unit 101 of the digital camera 100 associates the SSID and channel of the AP included in the received connection AP selection instruction as connection settings for the SSID and channel of the desired AP, and stores them in the working memory 104. The processing of S504 corresponds to S404 in FIG.

[0058] In S505, the control unit 101 of the digital camera 100 transmits a connection request to the AP to which the connection attempt is being made in order to perform connection processing in cooperation with the AP. The processing in S505 corresponds to S405 in FIG.

[0059] In S506, the control unit 101 of the digital camera 100 receives a connection OK notification from the AP to which the connection attempt is being attempted. The process of S506 corresponds to S406 in FIG.

[0060] In S507, the control unit 101 of the digital camera 100 determines that the AP to which the connection attempt is being made is the desired AP, and establishes a wireless LAN connection with this AP. After the connection is established, the control unit 101 transmits a notification of connection completion to the AP, and receives a notification of connection completion from the AP. The processing of S507 corresponds to S407 in FIG. 4.

[0061] In S508, the control unit 101 of the digital camera 100 determines whether a connection termination instruction has been received from the user, and if it determines that a connection termination instruction has been received, terminates the processing, and if it determines that a connection termination instruction has not been received, proceeds to S509.

[0062] In S509, the control unit 101 of the digital camera 100 determines whether the SNR of the connected AP has fallen below the SNR threshold. If the control unit 101 determines that the SNR of the connected AP has fallen below the SNR threshold, the process proceeds to S510. If the control unit 101 determines that the SNR of the connected AP has not fallen below the SNR threshold, the process returns to S508 and repeats S508 and subsequent steps.

[0063] In S510, the control unit 101 of the digital camera 100 specifies and scans an AP with the desired SSID stored in the work memory 104. During the scan, the control unit 101 acquires the frequency band of the connected AP and the frequency band of the roaming target AP. The processing of S510 corresponds to S408 in FIG. 4.

[0064] In S511, the control unit 101 of the digital camera 100 determines whether the frequency band of the roaming target AP is greater than the frequency band of the connected AP. If the control unit 101 determines that the frequency band of the roaming target AP is greater than the frequency band of the connected AP, the process proceeds to S512, and if the control unit 101 determines that the frequency band of the roaming target AP is not greater than the frequency band of the connected AP, the process proceeds to S513.

[0065] In S512, the control unit 101 of the digital camera 100 changes the SNR condition. The change in the SNR condition here is to raise the SNR threshold, which is a roaming condition. The process of S512 corresponds to S409 in FIG. 4.

[0066] In S513, the control unit 101 of the digital camera 100 changes the SNR condition. The change in the SNR condition here is to lower the SNR threshold, which is a roaming condition. The process of S513 corresponds to S409 in FIG. 4.

[0067] In S514, the control unit 101 of the digital camera 100 determines whether the roaming conditions are met based on the SNR of the connected AP and the SNR threshold. If the SNR of the connected AP is below the SNR threshold, the control unit 101 determines that the roaming conditions are met, and proceeds to S515 to execute roaming. On the other hand, if the SNR of the connected AP is not below the SNR threshold, the control unit 101 determines that the roaming conditions are not met, and returns to the processing of S508 without roaming.

[0068] In S515, the control unit 101 of the digital camera 100 transmits a connection request to the AP that is the target of roaming and the target of connection attempt, in order to perform connection processing in cooperation with that AP. The processing of S515 corresponds to S410 in FIG. 4.

[0069] In S516, the control unit 101 of the digital camera 100 receives a connection OK notification from the AP to which the connection attempt is being attempted. The process of S516 corresponds to S411 in FIG.

[0070] In S517, the control unit 101 of the digital camera 100 determines that the AP to which the connection attempt is being made is the desired AP, and establishes a wireless LAN connection with this AP. After the establishment of the connection, the control unit 101 transmits a notification of connection completion to the AP, and receives a notification of connection completion from the AP. The processing of S517 corresponds to S412 in FIG. 4.

[0071] According to the first embodiment, the digital camera 100 acquires the frequency band of the connected AP and the frequency band of the roaming target AP. Furthermore, when the digital camera 100 determines that the frequency band of the roaming target AP is higher than the frequency band of the connected AP, the digital camera 100 increases the SNR threshold, which is the SNR condition that constitutes a roaming condition, to make the transfer easier. Then, when the digital camera 100 determines that the roaming conditions are satisfied, it executes roaming. In this way, this embodiment reduces the decrease in throughput after roaming and makes it easier to roam to a frequency band with higher throughput.

[0072] (Second embodiment) Hereinafter, a roaming method according to the second embodiment will be described with reference to FIGS.

[0073] <Digital camera control sequence> The control sequence of the digital camera 100 of the second embodiment will be described with reference to Fig. 6. Fig. 6 is a sequence diagram showing the processing between the digital camera of the second embodiment and the AP.

[0074] In S601, the control unit 101 of the digital camera 100 receives a connection start instruction from the user via the operation unit 105. For example, as shown in FIG. 2A, with the setting screen 200 displayed on the display unit 106, the control unit 101 receives the user's selection of the new setting button 201, and then receives input of the OK button 203. This causes the control unit 101 to receive the connection start instruction.

[0075] In S602, the control unit 101 of the digital camera 100 scans to attempt wireless reception of a signal including the SSID and BSSID from each of one or more APs.

[0076] In S603, the control unit 101 of the digital camera 100 receives a connection AP selection instruction from the user via the operation unit 105. For example, as shown in FIG. 2B, the control unit 101 receives input from the connection button 212 while displaying a selection screen 210 on the display unit 106.

[0077] In S604, the control unit 101 of the digital camera 100 associates the SSID and channel of the AP corresponding to the connection AP selection instruction received in S403 as connection settings for the SSID and channel of the desired AP, and stores them in the working memory 104.

[0078] In S605, the control unit 101 of the digital camera 100 transmits a connection request to the AP to which the connection attempt is being made in order to perform connection processing in cooperation with that AP.

[0079] In S606, the control unit 101 of the digital camera 100 receives a connection OK notification from the AP to which the connection attempt is being attempted.

[0080] In S607, the control unit 101 of the digital camera 100 determines that the AP to which the connection attempt is being made is the desired AP, and establishes a wireless LAN connection with this AP. After establishing the wireless LAN connection, the control unit 101 displays a completion screen 220 on the display unit 106, as shown in FIG. 2(c), for example, and accepts input of an OK button 221 from the user. The control unit 101 transmits a notification of connection completion to the AP, and receives a notification of connection completion from the AP.

[0081] In S608, when the control unit 101 of the digital camera 100 determines that the RSSI of the connected AP has fallen below the RSSI threshold and that the communication degradation determination time has elapsed, the control unit 101 designates and scans an AP with the desired SSID stored in the working memory 104. In the scan, the control unit 101 acquires the frequency band of the connected AP and the frequency band of the roaming target AP. For example, when the control unit 101 determines that the RSSI of the connected AP has fallen below the RSSI threshold for the communication degradation determination time of "30 seconds," the control unit 101 designates and scans an AP with the desired SSID "Conon" stored in the working memory 104. In the scan, the control unit 101 acquires "2.4 GHz," which is the frequency band of the connected AP, and "6 GHz," which is the frequency band of the roaming target AP.

[0082] In S609, when the control unit 101 of the digital camera 100 determines that the frequency band of the connected AP and the frequency band of the roaming target AP are different, it changes the RSSI threshold as the RSSI condition, which is a roaming condition. For example, when the frequency band of the connected AP is "6 GHz" and the frequency band of the roaming target AP is "2.4 GHz," the control unit 101 determines that the frequency band of the roaming target AP is smaller than the frequency band of the connected AP and changes the RSSI threshold as the RSSI condition, which is a roaming condition, from the originally set "-50" to "-75." In other words, when the frequency band of the roaming target AP is smaller than the frequency band of the connected AP, the control unit 101 tightens the roaming condition, making roaming more difficult. Furthermore, when the frequency band of the connecting AP is "2.4 GHz" and the frequency band of the roaming target AP is "6 GHz," the control unit 101 determines that the frequency band of the roaming target AP is greater than the frequency band of the connecting AP, and changes the RSSI threshold, which is a roaming condition, from the originally set "-50" to "-25." In other words, when the frequency band of the roaming target AP is greater than the frequency band of the connecting AP, the control unit 101 relaxes the roaming condition to make roaming easier.

[0083] In S610, when the control unit 101 of the digital camera 100 determines that the frequency band of the roaming target AP is smaller than the frequency band of the connected AP, the control unit 101 changes the communication degradation determination time condition, which is a roaming condition. For example, the control unit 101 changes the communication degradation determination time condition, which is a roaming condition, from the originally set "30 seconds" to "60 seconds." In other words, when the frequency band of the roaming target AP is smaller than the frequency band of the connected AP, the control unit 101 makes roaming more difficult.

[0084] In S611, when the control unit 101 of the digital camera 100 determines that the roaming conditions are met, it transmits a connection request to the AP to which the connection attempt is being made in order to perform connection processing in cooperation with that AP.

[0085] In S612, the control unit 101 of the digital camera 100 receives a connection OK notification from the AP to which the connection attempt is being attempted.

[0086] In S613, the control unit 101 of the digital camera 100 determines that the AP to which the connection attempt is being made is the desired AP, and establishes a wireless LAN connection with this AP. After establishing the wireless LAN connection, the control unit 101 transmits a connection completion notification to the AP, and receives a connection completion notification from the AP.

[0087] <Digital camera control flow> The control flow of the digital camera 100 of the second embodiment will be described with reference to Fig. 7. Fig. 7 is a flowchart showing the processing of the digital camera of the second embodiment.

[0088] In S701, the control unit 101 of the digital camera 100 determines whether a connection start instruction has been received. If the control unit 101 determines that a connection start instruction has been received, the process proceeds to S702. If the control unit 101 determines that a connection start instruction has not been received, the process of S701 is repeated. The process of S701 corresponds to S601 in FIG. 6.

[0089] In S702, the control unit 101 of the digital camera 100 scans to attempt wireless reception of a signal including the SSID and BSSID from each of one or more APs. The processing of S702 corresponds to S602 in FIG.

[0090] In S703, the control unit 101 of the digital camera 100 determines whether a connection AP selection instruction has been received. If the control unit 101 determines that a connection AP selection instruction has been received, the process proceeds to S704. If the control unit 101 determines that a connection AP selection instruction has not been received, the process of S703 is repeated.

[0091] In S704, the control unit 101 of the digital camera 100 associates the SSID and channel included in the received connection AP instruction as connection settings for the SSID and channel of the desired AP, and stores them in the working memory 104. The processing of S704 corresponds to S604 in FIG.

[0092] In S705, the control unit 101 of the digital camera 100 transmits a connection request to the AP to which the connection attempt is being made in order to perform connection processing in cooperation with the AP. The processing in S705 corresponds to S605 in FIG.

[0093] In S706, the control unit 101 of the digital camera 100 receives a connection OK notification from the AP to which the connection attempt is being attempted. The process of S706 corresponds to S606 in FIG.

[0094] In S707, the control unit 101 of the digital camera 100 determines that the AP to which the connection attempt is being made is the desired AP, and establishes a wireless LAN connection with this AP. After the establishment, the control unit 101 transmits a connection completion notification to the AP, and receives a connection completion notification from the AP. The processing of S707 corresponds to S607 in FIG. 6.

[0095] In S708, the control unit 101 of the digital camera 100 determines whether a connection termination instruction has been received, and if it determines that a connection termination instruction has been received, it terminates the processing, and if it determines that a connection termination instruction has not been received, it proceeds to S709.

[0096] In S709, the control unit 101 of the digital camera 100 determines whether the RSSI of the connected AP has fallen below the RSSI threshold. If the control unit 101 determines that the RSSI of the connected AP has fallen below the RSSI threshold, the process proceeds to S710. If the control unit 101 determines that the RSSI of the connected AP has not fallen below the RSSI threshold, the process returns to S708 and repeats S708 and subsequent steps.

[0097] In S710, the control unit 101 of the digital camera 100 determines whether the time during which the RSSI of the connected AP has fallen below the RSSI threshold has exceeded the communication degradation determination time. If the control unit 101 determines that the time during which the RSSI of the connected AP has fallen below the RSSI threshold has exceeded the communication degradation determination time, the process proceeds to S711, but if the control unit 101 determines that the time during which the RSSI of the connected AP has fallen below the RSSI threshold has not exceeded the communication degradation determination time, the process returns to S708.

[0098] In S711, the control unit 101 of the digital camera 100 specifies and scans for an AP with the desired SSID stored in the work memory 104. During the scan, the control unit 101 acquires the frequency band of the connected AP and the frequency band of the roaming target AP. The processing of S711 corresponds to S608 in FIG. 6.

[0099] In S712, the control unit 101 of the digital camera 100 determines whether the frequency band of the roaming target AP is smaller than the frequency band of the connecting AP. If the control unit 101 determines that the frequency band of the roaming target AP is smaller than the frequency band of the connecting AP, the process proceeds to S713, and if the control unit 101 determines that the frequency band of the roaming target AP is not smaller than the frequency band of the connecting AP, the process proceeds to S715.

[0100] In S713, the control unit 101 of the digital camera 100 changes the RSSI condition. The change in the RSSI condition here is to lower the RSSI threshold, which is a roaming condition. The process of S713 corresponds to S609 in FIG. 6.

[0101] In S714, the control unit 101 of the digital camera 100 changes the time condition. The change in the time condition here is to lengthen the communication degradation determination time, which is a roaming condition. The process of S714 corresponds to S610 in FIG. 6.

[0102] In S715, the control unit 101 of the digital camera 100 changes the RSSI condition. The change in the RSSI condition here is to raise the RSSI threshold, which is a roaming condition. The process of S713 corresponds to S609 in FIG. 6.

[0103] In S716, the control unit 101 of the digital camera 100 changes the time condition. The change in the time condition here is to shorten the communication degradation determination time, which is a roaming condition. The process of S714 corresponds to S610 in FIG. 6.

[0104] In S717, the control unit 101 of the digital camera 100 determines whether the roaming conditions are met based on the RSSI threshold and the communication degradation determination time, and if it is determined that the roaming conditions are met, the process proceeds to S718 and roaming is performed. Specifically, the control unit 101 determines that the roaming conditions are met if the RSSI of the connected AP falls below the RSSI threshold and the time that it remains below the RSSI threshold has elapsed for the communication degradation determination time. On the other hand, if the control unit 101 determines that the roaming conditions are not met, the process returns to S708 without roaming.

[0105] In S718, the control unit 101 of the digital camera 100 transmits a connection request to the AP that is the target of roaming and the target of connection attempt, in order to perform connection processing in cooperation with that AP. The processing of S718 corresponds to S611 in FIG. 6.

[0106] In S719, the control unit 101 of the digital camera 100 receives a connection OK notification from the AP to which the connection attempt is being attempted. The process of S719 corresponds to S612 in FIG.

[0107] In S720, the control unit 101 of the digital camera 100 determines that the AP to which the connection attempt is being made is the desired AP, and establishes a wireless LAN connection with this AP. After the connection is established, the control unit 101 transmits a connection completion notification to the AP, and receives a connection completion notification from the AP. The processing of S720 corresponds to S613 in FIG. 6.

[0108] According to the second embodiment, the digital camera 100 acquires the frequency band of the connected AP and the frequency band of the roaming target AP. Furthermore, when the digital camera 100 determines that the frequency band of the roaming target AP is smaller than the frequency band of the connected AP, the digital camera 100 reduces the RSSI threshold, which is the RSSI condition that constitutes a roaming condition, to make the transition more difficult. Furthermore, when the digital camera 100 determines that the frequency band of the roaming target AP is smaller than the frequency band of the connected AP, the digital camera 100 reduces the communication degradation determination time condition that constitutes a roaming condition to make the transition more difficult. Then, when the digital camera 100 determines that the roaming conditions are met, it performs roaming. In this way, this embodiment makes it possible to reduce the decrease in throughput after roaming and to facilitate roaming to a frequency band with higher throughput.

[0109] Although the preferred embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and various modifications and changes are possible within the scope of the gist of the present invention.

[0110] The above-described embodiments may be combined, or some processes may be omitted. For example, in the first embodiment, the control unit 101 may change the SNR threshold when the communication degradation determination time has elapsed while the SNR of the connected AP is below the SNR threshold. In the second embodiment, the control unit 101 may change the RSSI threshold when the RSSI of the connected AP is below the RSSI threshold, even if the communication degradation determination time has not elapsed. The control unit 101 may be configured to determine the roaming condition based on either the SNR or the RSSI, and the user may be able to select either the SNR threshold or the RSSI threshold.

[0111] In the above-described embodiment, the frequency band of the connecting AP and the frequency band of the roaming target AP are compared, and the SNR threshold or the RSSI threshold is changed regardless of which is larger. However, the present invention is not limited to this. For example, the threshold may be changed only when the frequency band of the roaming target AP is larger than the frequency band of the connecting AP, or only when the frequency band of the roaming target AP is smaller than the frequency band of the connecting AP.

[0112] For example, in the first embodiment described above, the process from S408 onward is executed when the SNR falls below the SNR threshold, but the condition for executing the process from S408 onward is not limited to this. For example, instead of or in addition to the above condition, the process from S408 onward may be executed when the signal strength of the connected AP falls below an intensity threshold (e.g., 15).

[0113] For example, in the second embodiment described above, the process from S608 onward is executed when the RSSI falls below the RSSI threshold, but the condition for executing the process from S608 onward is not limited to this. For example, instead of or in addition to the above condition, the process from S608 onward may be executed when the state in which the signal strength of the connected AP falls below the strength threshold (e.g., 15) has elapsed for a communication degradation determination time (e.g., 30 seconds).

[0114] (Other embodiments) The present invention can also be realized by supplying a program that realizes one or more functions of the above-described embodiments to a system or device via a network or a storage medium, and having one or more processors in the computer of the system or device read and execute the program.The present invention can also be realized by a circuit (e.g., ASIC) that realizes one or more functions.

[0115] The disclosure of this specification includes the following communication device, communication method, and program. (Item 1) an acquisition means for acquiring information on a plurality of access points in different frequency bands; a change means for changing a roaming condition for performing roaming by comparing a frequency band currently being connected with a frequency band to be roamed; an execution means for executing roaming when a signal of a frequency band currently being connected satisfies the roaming condition; A communication device comprising: (Item 2) The changing means changes a condition of a signal-to-noise ratio (SNR) as the roaming condition. 2. The communication device according to item 1, (Item 3) The changing means changes a condition of a received signal strength indicator (RSSI) as the roaming condition. 3. The communication device according to claim 1 or 2, (Item 4) The change means changes a determination time for determining a time when communication time is deteriorating as the roaming condition. 4. The communication device according to any one of items 1 to 3, wherein: (Item 5) The changing means relaxes the SNR condition when the frequency band to be roamed is larger than the frequency band currently being connected. 3. The communication device according to item 2. (Item 6) The changing means makes the SNR condition stricter when the frequency band to be roamed is smaller than the frequency band currently being connected. 6. The communication device according to item 2 or 5, (Item 7) The changing means relaxes the RSSI condition when the frequency band to be roamed is larger than the frequency band currently being connected. 4. The communication device according to item 3, (Item 8) The changing means makes the RSSI condition stricter when the frequency band to be roamed is smaller than the frequency band currently being connected. 8. The communication device according to claim 3 or 7, (Item 9) The change means shortens the determination time when the frequency band to be roamed is larger than the frequency band currently being connected. 5. The communication device according to item 4, (Item 10) The change means increases the determination time when the frequency band to be roamed is smaller than the frequency band currently being connected. 10. The communication device according to item 4 or 9, (Item 11) Acquire information on multiple access points using different frequency bands, The roaming conditions for performing roaming are changed by comparing the currently connected frequency band with the frequency band to be roamed, Execute roaming when the signal of the frequency band currently being connected satisfies the roaming condition. A communication method comprising: (Item 12) A program for causing a computer to function as each means of the communication device according to any one of items 1 to 10.

[0116] The invention is not limited to the above-described embodiments, and various changes and modifications can be made without departing from the spirit and scope of the invention. Accordingly, the following claims are appended to apprise the public of the scope of the invention. [Explanation of symbols]

[0117] 100···Digital camera, 101···Control unit, 301···AP, 302···AP.

Claims

1. an acquisition means for acquiring information on a plurality of access points in different frequency bands; a change means for relaxing the roaming conditions for performing roaming when the frequency band to be roamed is larger than the frequency band currently being connected; an execution means for executing roaming when a signal of a frequency band currently being connected satisfies the roaming condition; A communication device comprising:

2. The change means tightens the roaming conditions when the frequency band to be roamed is smaller than the frequency band currently being connected.

2. The communication device according to claim 1.

3. The changing means changes a condition of a signal-to-noise ratio (SNR) as the roaming condition.

2. The communication device according to claim 1.

4. The change means changes a condition of a received signal strength indicator (RSSI) as the roaming condition.

2. The communication device according to claim 1.

5. The change means changes a determination time for determining a time when communication time is deteriorating as the roaming condition.

5. The communication device according to claim 4.

6. The changing means relaxes the SNR condition when the frequency band to be roamed is larger than the frequency band currently being connected.

4. The communication device according to claim 3.

7. The changing means makes the SNR condition stricter when the frequency band to be roamed is smaller than the frequency band currently being connected.

4. The communication device according to claim 3.

8. The changing means relaxes the RSSI condition when the frequency band to be roamed is larger than the frequency band currently being connected.

5. The communication device according to claim 4.

9. The changing means makes the RSSI condition stricter when the frequency band to be roamed is smaller than the frequency band currently being connected.

5. The communication device according to claim 4.

10. The change means shortens the determination time when the frequency band to be roamed is larger than the frequency band currently being connected.

6. The communication device according to claim 5.

11. The change means increases the determination time when the frequency band to be roamed is smaller than the frequency band currently being connected.

6. The communication device according to claim 5.

12. Acquire information on multiple access points using different frequency bands, If the frequency band to be roamed is larger than the frequency band currently being connected, the roaming conditions for performing roaming are relaxed, Execute roaming when the signal of the frequency band currently being connected satisfies the roaming condition. A communication method comprising:

13. A program for causing a computer to function as each of the means of the communication device according to any one of claims 1 to 11.

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