Communication devices, communication methods, and programs

Abstract

To provide a communication device capable of efficiently achieving both data communication and scanning.SOLUTION: A communication device 10 that performs wireless communication via a master unit includes a communication section 11 for performing wireless communication with an apparatus connected to the master unit via the master unit, a memory section 13 that stores contents of data transmission and reception with the apparatus, and a control section 12 that, when a request to perform a scan is received, determines whether or not there is a high possibility of future data communication with the apparatus based on contents of transmission and reception performed within a predetermined period prior to the time the request stored in the memory section 13 was received, and controls execution of the scan based on a result of the determination.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a communication device such as a slave device that performs wireless communication with a master device.

Background Art

[0002] Patent Document 1 describes a technique for suppressing a decrease in throughput when a slave device that performs wireless communication with a master device scans another base station (master device) that becomes a handover destination.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When a slave device that performs wireless communication with a master device performs scanning, communication with the connected master device may be interrupted, resulting in a decrease in the throughput of data communication. As a technique for suppressing such a decrease in throughput, in addition to the technique described in Patent Document 1, for example, there is also a technique of not performing scanning when a certain period of time has not elapsed since the last data transmission / reception. However, if scanning is not performed uniformly when a certain period of time has not elapsed, there are problems such as a decrease in the scanning execution rate and a delay in the start of data communication for a certain period of time. In contrast, it is desired to efficiently balance data communication and scanning.

[0005] The present invention has been made to solve the above problems, and an object thereof is to provide a communication device or the like that can efficiently balance data communication and scanning.

Means for Solving the Problems

[0006] To solve the above problems, a communication device according to one aspect of the present invention is a communication device that performs wireless communication via a master unit, comprising: a communication unit for performing wireless communication with a device connected to the master unit via the master unit; a storage unit for storing the contents of data transmission and reception with the device; and a control unit that, when a request to perform a scan is received, determines whether there is a high probability of future data communication with the device based on the contents of transmission and reception performed within a predetermined period retrospectively from the time the request was received, and controls the execution of the scan based on the result of the determination.

[0007] According to this, the content of data transmission and reception with the device within a predetermined period preceding the time the request was received may include information indicating whether or not there is a high probability of future data communication with the device. Therefore, it is possible to determine whether or not there is a high probability of future data communication with the device based on the content of data transmission and reception with the device within a predetermined period preceding the time the request was received. If there is a high probability of future data communication with the device, the timing of the scan start can be adjusted while prioritizing data communication. If there is a low probability of future data communication with the device, the scan can be prioritized, thus efficiently balancing data communication and scanning.

[0008] Furthermore, if the control unit determines that there is a high probability of future data communication with the device, it may not perform a scan in response to the request. If the control unit determines that there is a low probability of future data communication with the device, it may perform a scan in response to the request.

[0009] According to this, if the likelihood of future data communication with the device is low, the system can perform the scan in response to the current scan request. On the other hand, if the likelihood of future data communication with the device is high, the system can prioritize data communication in response to the current scan request and perform the scan when the likelihood of future data communication with the device decreases.

[0010] Furthermore, if the control unit determines that it is unlikely to communicate data with the device in the future, it may perform a foreground scan or a background scan in response to the request.

[0011] According to this, even if the likelihood of future data communication with a device is low, data communication may still occur depending on the circumstances. Therefore, when the likelihood of future data communication with a device is low, determining the type of scan based on the situation and performing either a foreground scan or a background scan can more efficiently balance data communication and scanning.

[0012] Furthermore, if the contents of the transmission and reception performed within a predetermined period retrospectively from the time the request was received contain information indicating that there is little likelihood of future data communication, the control unit may perform a foreground scan in response to the request.

[0013] According to this, if the content of data transmission and reception with a device within a predetermined period preceding the time the request was received indicates that there is little likelihood of future data communication, the system can prioritize the scan and refrain from performing data communication while a foreground scan is in progress.

[0014] Furthermore, if the control unit has not performed the transmission or reception within a predetermined period of time prior to the time the request was received, and a connection has been established with the device, it may perform a background scan in response to the request.

[0015] According to this, even if no data has been transmitted or received between the device and the system within a predetermined period of time prior to the time the request was received, data communication may still occur if a connection has been established with the device. Therefore, by performing a background scan, it is possible to perform data communication at the timing of the channel switchover during the scan.

[0016] Furthermore, if the control unit determines that there is a high probability of future data communication with the device, it may instruct the requesting party to make the request again after a predetermined period of time.

[0017] According to this, if there is a high probability of future data communication with the device, the requesting party is instructed to make another request after a predetermined time, so that the scan can be performed when the likelihood of future data communication with the device has decreased.

[0018] Furthermore, if the control unit determines that there is a high probability of future data communication with the device, it may, after a predetermined time, determine again, based on the contents of the transmission and reception stored in the storage unit, whether there is a high probability of future data communication with the device, and control the execution of the scan based on the result of that determination.

[0019] According to this, if there is a high probability of future data communication with the device, a determination is made again after a predetermined time to see whether there is a high probability of future data communication with the device. Therefore, a scan can be performed when the probability of future data communication with the device has decreased.

[0020] Furthermore, if the control unit determines that there is a high probability of future data communication with the device if the content of the transmission and reception performed within a predetermined period retrospectively from the time the request was received indicates transmission and reception of ARP (Address Resolution Protocol), TCP (Transmission Control Protocol), or DHCP (Dynamic Host Configuration Protocol).

[0021] In this way, it is possible to determine that there is a high probability of future data communication with the device.

[0022] Further, when the content of the transmission / reception performed within a predetermined period retroactively from the time when the request was received indicates UDP (User Datagram Protocol) transmission / reception, or when there is no content of the transmission / reception performed within a predetermined period retroactively from the time when the request was received, the control unit may determine that the possibility of future data communication with the device is low.

[0023] In this way, it is possible to determine that the possibility of future data communication with the device is low.

[0024] In order to solve the above problems, a communication method according to an aspect of the present invention is a communication method executed by a communication device that performs wireless communication via a master device. The communication device includes a communication unit for performing wireless communication with a device connected to the master device via the master device, and a storage unit for storing the content of data transmission / reception with the device. In the communication method, when the communication device receives a request to execute a scan, based on the content of the transmission / reception performed within a predetermined period retroactively from the time when the request was received and stored in the storage unit, a step of determining whether the possibility of future data communication with the device is high or not, and a step of controlling the execution of the scan for the device based on the result of the determination are included.

[0025] According to this, it is possible to provide a communication method capable of efficiently achieving both data communication and scanning.

[0026] In order to solve the above problems, a program according to an aspect of the present invention causes a computer to execute the above communication method.

[0027] According to this, it is possible to provide a program capable of efficiently achieving both data communication and scanning.

Effects of the Invention

[0028] According to the present invention, it is possible to efficiently achieve both data communication and scanning.

Brief Description of the Drawings

[0029] [Figure 1] This is a configuration diagram showing an example of a communication system according to an embodiment. [Figure 2] This is a configuration diagram showing an example of a communication device according to an embodiment. [Figure 3] This flowchart shows an example of the operation of a communication device according to an embodiment. [Figure 4] This figure shows an example of the content of data sent and received between a sub-unit and a client device. [Figure 5] A flowchart showing an example of controlling the execution of a scan in an embodiment. [Figure 6] This sequence diagram shows an example of the operation when no scan is performed. [Figure 7] This is a sequence diagram illustrating an example of how a foreground scan works. [Figure 8] This is a sequence diagram illustrating an example of how background scans work. [Modes for carrying out the invention]

[0030] The embodiments will be described in detail below with reference to the drawings.

[0031] The embodiments described below are all preferred examples of the present invention. The numerical values, shapes, materials, components, arrangement and connection configurations of components, steps, and the order of steps shown in the following embodiments are examples only and are not intended to limit the present invention. Furthermore, components in the following embodiments that are not described in an independent claim are described as any component that constitutes a more preferred form. Note that the same reference numerals are used for the same components, and their descriptions may be omitted.

[0032] (Embodiment) The embodiments will be described below with reference to Figures 1 to 8.

[0033] Figure 1 is a configuration diagram showing an example of a communication system 1 according to an embodiment.

[0034] In communication system 1, multiple slave units (e.g., STAs: stations) 100 and a communication device 10 are connected to a single master unit (e.g., AP: access point) 200. In infrastructure mode, each of the multiple slave units 100 and the communication device 10 can communicate with each other via the master unit 200. The master unit 200, each slave unit 100, and the communication device 10 are connected via a wireless LAN (Local Area Network). The multiple slave units 100 may collectively be referred to as slave units 100 from now on.

[0035] The communication device 10 may, for example, scan for wireless frames in its vicinity to investigate the surrounding wireless environment or to find a potential roaming base station 200. Here, when the communication device 10 performs a scan, it means that it acquires wireless frames that are within the range where it can receive wireless communications. Since the communication device 10 performs the scan using a channel different from the channel currently used for communication with the base station 200 to which it is connected, it will be unable to communicate data with the base station 200 to which it is currently connected during the scan. For this reason, it is desirable to efficiently balance data communication and scanning. The following describes a communication device 10 that can efficiently balance data communication and scanning in such a communication system 1.

[0036] Figure 2 is a configuration diagram showing an example of a communication device 10 according to an embodiment.

[0037] The communication device 10 is a communication device that performs wireless communication via the master unit 200, and is, for example, a wireless terminal such as a mobile terminal (smartphone, tablet terminal, etc.) or a node PC (Personal Computer), or a network device. In this embodiment, the communication device 10 is described as performing wireless communication with a plurality of slave units 100 via the master unit 200, but it is not limited to this, and may also communicate with other communication devices (not shown) connected to the master unit 200 via other networks. The communication device 10 comprises a communication unit 11, a control unit 12, and a storage unit 13. The communication device 10 is a computer equipped with hardware such as a processor, memory, and a communication interface. The memory is such as ROM (Read Only Memory) and RAM (Random Access Memory), and can store programs executed by the processor. The control unit 12 is implemented by a processor that executes programs stored in memory. The communication unit 11 is implemented by a communication program, a communication circuit, and a communication interface such as an antenna, and can send and receive information by being controlled by the control unit 12. For example, the communication interface of the communication unit 11 is a wireless interface compliant with the IEEE 802.11 communication standard. The storage unit 13 is implemented by memory, but the memory in which the program is stored and the storage unit 13 may be separate memories.

[0038] The communication unit 11 is a processing unit for performing wireless communication with the slave unit 100 via the master unit 200. The slave unit 100 is an example of a device connected to the master unit 200. As described above, the communication unit 11 may also perform wireless communication with other communication devices (not shown) connected to the master unit 200 via other networks. In this case, the other communication device is an example of a device connected to the master unit 200. For example, when the slave unit 100 is wirelessly connected to the master unit 200, the communication unit 11 can perform wireless communication with the slave unit 100 via the master unit 200.

[0039] The storage unit 13 stores the contents of data transmission and reception between the communication unit 11 and the slave unit 100 during wireless communication. Examples of the contents of data transmission and reception with the slave unit 100 stored in the storage unit 13 will be described later. The storage unit 13 may also store the status of connection establishment with the slave unit 100. Furthermore, the storage unit 13 may store information obtained by, for example, performing a scan, which contains various data (information) stored in the wireless frame.

[0040] When the control unit 12 receives a request to perform a scan from a user using the communication device 10 via the input unit (not shown), it determines whether there is a high probability of future data communication with the slave device 100 based on the data transmission and reception with the slave device 100 that occurred within a predetermined period of time preceding the time the request was received, as stored in the storage unit 13, and controls the execution of the scan based on the result of this determination. Hereinafter, a request to perform a scan will also be referred to as a scan request. A scan request is made, for example, to investigate the surrounding wireless environment or to find roaming candidate destinations. The source of the scan request may be an application installed on the communication device 10, in addition to a user operating the communication device 10.

[0041] Next, the operation of the communication device 10 (specifically the control unit 12) will be explained using Figure 3.

[0042] Figure 3 is a flowchart showing an example of the operation of the communication device 10 according to the embodiment.

[0043] First, the control unit 12 determines whether or not it has received a request to perform a scan (scan request) (step S11).

[0044] If the control unit 12 does not receive a scan request (No in step S11), it repeats the processing in step S11 until it receives a scan request. In other words, the control unit 12 waits until it receives a scan request in step S11.

[0045] When the control unit 12 receives a scan request (Yes in step S11), it determines whether there is a high probability of future data communication with the slave unit 100 based on the contents of transmissions and receptions performed within a predetermined period of time retrospectively from the time the scan request was received, which are stored in the storage unit 13 (step S12). An example of the contents of data transmissions and receptions with the slave unit 100 stored in the storage unit 13 will be explained using Figure 4.

[0046] Figure 4 shows an example of the content of data transmission and reception with the slave unit 100.

[0047] For example, the storage unit 13 stores the contents of the data frame header, specifically the type of protocol included in the header, the type of packet, and the timestamp (the time of transmission and reception). For example, Figure 4 shows ARP (Address Resolution Protocol) and UDP (User Datagram Protocol) as types of protocols.

[0048] ARP is a protocol for obtaining an Ethernet® MAC (Media Access Control) address from an IP address, and ARP data frames are sent and received to perform data communication. ARP packets have two types: Request and Reply. For example, communication device 10 broadcasts an ARP Request containing the IP address for which it wants to know the MAC address via the master unit 200, and the slave unit 100 with that IP address sends an ARP Reply containing its own MAC address to communication device 10 via the master unit 200. This allows communication device 10 and slave unit 100 to perform data communication thereafter. Thus, when an ARP Request necessary for data communication is sent, there is a high probability that an ARP Reply will be sent in response.

[0049] UDP is a connectionless communication protocol, primarily suited for real-time data communication such as video and audio, high-speed data communication, and data communication where responsiveness is paramount, such as name resolution for DNS (Domain Name System). Unlike TCP (Transmission Control Protocol), UDP does not establish a connection through a three-way handshake.

[0050] Although not shown in the diagram, TCP is one of the types of protocols stored in the memory unit 13. TCP is a connection-oriented communication protocol and is suitable for data communication where reliability is required. Before data communication is performed by TCP, a connection is established through a three-way handshake. The types of packets used when establishing a TCP connection are SYN, SYN / ACK, and ACK. For example, the communication device 10 sends a SYN packet to the slave device 100 that wants to establish a connection via the master device 200. The slave device 100, having received the SYN packet, sends a SYN / ACK packet to the communication device 10 via the master device 200. The communication device 10 then sends an ACK packet to the slave device 100 via the master device 200. This establishes a connection between the communication device 10 and the slave device 100.

[0051] In addition to the protocol type, packet type, and timestamp, the storage unit 13 may also store information such as the port number, IP address, or MAC address when transmitting and receiving data with the slave device 100. Thus, in TCP communication, where data communication occurs after a connection is established, there is a high probability that data communication will occur once the three-way handshake to establish the connection is initiated, and there is also a possibility that some data communication will occur even after the connection has been established.

[0052] Furthermore, the contents of the data transmitted and received with the slave unit 100 stored in the memory unit 13 may be deleted starting with the oldest data.

[0053] Here, using various protocol types as shown in Figure 4 as examples, a specific example of how the communication device 10 determines whether there is a high probability of future data communication with the slave device 100 based on the content of data transmission and reception with the slave device 100 that occurred within a predetermined period of time, retrospectively from the time the scan request was received, will be explained. The control unit 12 determines whether there is a high probability of future data communication with the slave device 100 based on the content of data transmission and reception with the slave device 100 that occurred within a predetermined period of time, retrospectively from the time the scan request was received, which is stored in the storage unit 13. The predetermined period is not particularly limited and is set as appropriate depending on the system to which the communication device 10 is applied.

[0054] For example, if the control unit 12 determines that there is a high probability of future data communication with the slave device 100 if the content of transmissions and receptions performed within a predetermined period retrospectively from the time the scan request was received indicates the transmission and reception of ARP. This is because ARP transmissions and receptions are being performed between the communication device 10 and the slave device 100 in order to initiate future data communication, and therefore there is a high probability of future data communication.

[0055] For example, if the control unit 12 determines that the likelihood of future data communication with the slave device 100 is low when the content of transmissions and receptions performed within a predetermined period retrospectively from the time the scan request was received indicates that the transmissions and receptions are one-off data such as UDP, it determines that there is a low likelihood of further data communication between the control unit 10 and the slave device 100. This is because a one-off data communication has occurred between the communication device 10 and the slave device 100, and there is a low likelihood of continued data communication in the future.

[0056] For example, the control unit 12 determines that there is a high probability of future data communication with the slave device 100 if the content of transmissions and receptions performed within a predetermined period retrospectively from the time the scan request was received indicates TCP transmission and reception, or indicates the transmission and reception of SYN, SYN / ACK, and ACK packets when a TCP connection is established. This is because TCP data transmission and reception have occurred between the communication device 10 and the slave device 100, or a TCP connection has been established and data communication is about to begin, making it highly likely that data communication will occur in the future.

[0057] For example, if the control unit 12 finds no data transmission or reception activity within a predetermined period of time prior to the time the scan request was received, that is, if no data communication occurred within that predetermined period, it determines that the likelihood of future data communication with the slave unit 100 is low. This is because no data communication has occurred between the communication device 10 and the slave unit 100, and the likelihood of future data communication is low.

[0058] Returning to the explanation in Figure 3, the control unit 12 controls the execution of the scan based on the result of the determination of whether or not there is a high probability of future data communication with the slave unit 100 (step S13). Here, an example of the control of the execution of the scan will be explained using Figure 5.

[0059] Figure 5 is a flowchart showing an example of controlling the execution of a scan in an embodiment.

[0060] The control unit 12 determines whether there is a high probability of future data communication with the slave unit 100 (step S21). Specifically, as described above, this determination is made based on the contents of transmissions and receptions that occurred within a predetermined period of time, retrospectively from the time the scan request was received, which are stored in the storage unit 13.

[0061] If the control unit 12 determines that there is a high probability of future data communication with the slave unit 100 (Yes in step S21), it will not perform a scan in response to the scan request (step S22). If there is a high probability of future data communication with the slave unit 100, it will not perform a scan in response to the scan request received this time, prioritizing data communication, and can perform a scan when the likelihood of future data communication with the slave unit 100 decreases.

[0062] For example, if the control unit 12 determines that there is a high probability of future data communication with the slave unit 100, it instructs the requester of the scan request to submit another scan request after a predetermined time (step S23). Since the requester is instructed to submit another scan request after a predetermined time if there is a high probability of future data communication with the slave unit 100, the scan can be performed when the likelihood of future data communication with the slave unit 100 decreases. The predetermined time is not particularly limited and is set as appropriate depending on the system to which the communication device 10 is applied.

[0063] Furthermore, if the control unit 12 determines that there is a high probability of future data communication with the slave unit 100, it may not instruct the requester of the scan request to make another scan request after a predetermined time. Instead, for example, after a predetermined time, it may determine again, based on the transmitted and received data stored in the storage unit 13, whether there is a high probability of future data communication with the slave unit 100, and control the execution of the scan based on the result of that determination. In other words, even without a second scan request, the system may automatically return to step S21 after a predetermined time to determine again whether there is a high probability of future data communication with the slave unit 100. In this way, if there is a high probability of future data communication with the slave unit 100, the system will determine again after a predetermined time whether there is a high probability of future data communication with the slave unit 100, and therefore the scan can be executed when the probability of future data communication with the slave unit 100 decreases.

[0064] On the other hand, if the control unit 12 determines that there is little likelihood of future data communication with the slave unit 100 (No in step S21), it performs a scan in response to the scan request (step S24). If there is little likelihood of future data communication with the slave unit 100, it can perform a scan in response to the current scan request.

[0065] Here, the operation of the communication device 10, master unit 200, slave unit 100, and user when a scan is not performed will be explained using Figure 6.

[0066] Figure 6 is a sequence diagram showing an example of the operation when no scan is performed.

[0067] For example, suppose that the communication device 10 and the master unit 200 are connected via wireless LAN, and the master unit 200 and the slave unit 100 are connected via wireless LAN.

[0068] For example, when the communication device 10 (control unit 12) receives a scan request, it determines whether the content of transmissions and receptions performed within a predetermined period (e.g., 1 second) prior to the time the scan request was received contains information that suggests a high probability of future data communication. As shown in Figure 6, ARP transmission and reception have been performed within 1 second prior to the time the scan request was received from the user via an input unit (not shown) provided by the communication device 10, and the content of the transmission and reception contains information that suggests a high probability of future data communication. Therefore, the communication device 10 rejects the scan request and does not perform the scan. As another example, if the content of transmissions and receptions performed within a predetermined period prior to the time the scan request was received is a DHCP (Dynamic Host Configuration Protocol) transmission and reception, the DHCP transmission and reception also indicate a high probability of future data communication. Therefore, the communication device 10 does not need to reject the scan request or perform the scan.

[0069] The communication device 10 scans for candidate channels that can be used for communication, one channel at a time, and there are two types of scans: foreground scans and background scans. For example, if the control unit 12 determines that it is unlikely to communicate data with the slave device 100 in the future, it will perform either a foreground scan or a background scan in response to a scan request.

[0070] Foreground scanning is a method of scanning by continuously switching between channels one at a time. For example, suppose the channel used by the communication device 10 for communication with the connected master unit 200 is channel 1, and the channels that can be used for communication pre-configured on the device are channel 2, channel 3, ... In this case, during foreground scanning, the device switches from channel 1 to channel 2 and scans channel 2 for a predetermined time (e.g., 100 ms), then switches from channel 2 to channel 3 and scans channel 3 for a predetermined time. This process continues until all channels that are pre-configured to be scanned on the device have been scanned. Therefore, while the communication device 10 is performing a foreground scan, data communication with the slave unit 100 is not possible.

[0071] On the other hand, background scanning is a method of scanning by alternately switching between the channel to be scanned and the channel used by the communication device 10 for communication with the master unit 200 to which it is connected. For example, suppose the channel used by the communication device 10 for communication with the master unit 200 to which it is connected is the first channel, and the channels to be scanned are the second channel, the third channel, ... In this case, during background scanning, the system switches from the first channel to the second channel and scans the second channel for a predetermined time (e.g., 100ms), and then switches from the second channel to the first channel to check whether data communication with the slave device 100 has occurred. Specifically, if the master unit 200 receives data from the slave device 100 to the communication device 10 while the second channel is being scanned, the master unit 200 buffers the data and transmits it to the communication device 10 when it switches back to the first channel. This allows the communication device 10 to perform data communication with the slave device 100 while simultaneously performing background scanning.

[0072] Next, the system switches from channel 1 to channel 3 and scans channel 3 for a predetermined period of time. Then, it switches back from channel 3 to channel 1 to check if any data communication with the master unit 200 is occurring. This process is repeated until all channels pre-configured for scanning on the device have been scanned.

[0073] For example, if the control unit 12 finds that the content of transmissions and receptions made within a predetermined period preceding the time the scan request was received contains information indicating that future data communication is unlikely, it will perform a foreground scan in response to the scan request.

[0074] Here, the operation of the communication device 10, master unit 200, slave unit 100, and user when performing a foreground scan will be explained using Figure 7.

[0075] Figure 7 is a sequence diagram showing an example of the operation when performing a foreground scan.

[0076] For example, suppose that the communication device 10 and the master unit 200 are connected via wireless LAN, and the master unit 200 and the slave unit 100 are connected via wireless LAN.

[0077] For example, when the communication device 10 (control unit 12) receives a scan request, it determines whether the content of transmissions and receptions performed within a predetermined period (e.g., 10 seconds) prior to the time the scan request was received indicates that there is a high probability of future data communication. As shown in Figure 7, since only two UDP receptions have occurred within 10 seconds prior to the time the scan request was received from the user via the input unit (not shown) of the communication device 10, and the content of the transmissions and receptions indicates that there is a low probability of future data communication, the communication device 10 performs a foreground scan in response to the scan request.

[0078] Thus, if the content of data transmission and reception with the slave unit 100 within a predetermined period preceding the time the scan request was received contains information indicating that there is little likelihood of future data communication, the system can prioritize the scan and refrain from performing data communication while the foreground scan is in progress.

[0079] For example, if the control unit 12 determines that no transmission or reception has occurred within a predetermined period of time prior to the time the scan request was received, and that a connection has been established with the slave unit 100, it will determine that the likelihood of future data communication is low. However, to avoid the risk of not being able to receive data during the scan, it will perform a background scan in response to the scan request.

[0080] Here, the operation of the communication device 10, the master unit 200, the slave unit 100, and the user when performing a background scan will be explained using Figure 8.

[0081] Figure 8 is a sequence diagram showing an example of the operation when performing a background scan.

[0082] For example, suppose that the communication device 10 and the master unit 200 are connected via wireless LAN, and the master unit 200 and the slave unit 100 are connected via wireless LAN.

[0083] For example, when the communication device 10 (control unit 12) receives a scan request, it determines whether the content of transmissions and receptions performed within a predetermined period (e.g., 10 seconds) retrospectively from the time the scan request was received indicates information that suggests a high probability of future data communication. As shown in Figure 8, if more than 10 seconds have passed since the last data transmission or reception, the communication device 10 determines that there is little possibility of future data communication because no transmissions or receptions have occurred within a predetermined period (e.g., 10 seconds) retrospectively from the time the scan request was received. On the other hand, it determines whether a connection has been established between the communication device 10 and the slave device 100. For example, the storage unit 13 may store information about the status of connection establishment with the slave device 100, and the communication device 10 can determine whether a connection has been established between the communication device 10 and the slave device 100 by referring to the storage unit 13. As shown in Figure 8, a TCP connection has been established between the communication device 10 and the slave device 100, so in this case, the communication device 10 performs a background scan in response to the scan request.

[0084] Thus, even if no data has been transmitted or received between the child device 100 and the master device 200 within a predetermined period preceding the time the scan request was received, data communication may still occur if a connection has been established with the child device 100. Therefore, by performing a background scan, it is possible to initiate data communication via the master device 200 at the timing of the channel switchover. Furthermore, if no data has been transmitted or received between the child device 100 and the master device 200 within a predetermined period preceding the time the scan request was received, and a connection has not been established with the child device 100, then a foreground scan is performed in response to the scan request because the likelihood of future data communication with the child device 100 is low.

[0085] In this way, when the likelihood of future data communication with the slave unit 100 is low, the system can determine the type of scan based on the situation and perform either a foreground scan or a background scan, thereby more efficiently balancing data communication and scanning.

[0086] As explained above, the data transmitted and received with the slave unit 100 within a predetermined period of time, retrospectively from the time the scan request was received, may contain information indicating whether or not there is a high probability of future data communication with the slave unit 100. Therefore, based on the data transmitted and received with the slave unit 100 within a predetermined period of time, retrospectively from the time the scan request was received, it is possible to determine whether or not there is a high probability of future data communication with the slave unit 100. If there is a high probability of future data communication with the slave unit 100, the timing of the scan start can be adjusted while prioritizing data communication. If there is a low probability of future data communication with the slave unit 100, the scan can be prioritized, thus efficiently balancing data communication and scanning.

[0087] (Other embodiments) As described above, embodiments have been explained as examples of the technology according to the present invention. However, the technology according to the present invention is not limited thereto and can be applied to embodiments that are modified, replaced, added, or omitted as appropriate. For example, the following modified examples are also included in one embodiment of the present invention.

[0088] For example, the present invention can be implemented not only as a communication device 10, but also as a communication method that includes steps (processes) performed by the components constituting the communication device 10.

[0089] The communication method is a communication method performed by a communication device 10 that performs wireless communication via a master unit 200, and the communication device 10 comprises a communication unit 11 for performing wireless communication with a device (slave unit 100) connected to the master unit 200 via the master unit 200, and a storage unit 13 for storing the contents of data transmission and reception with the slave unit 100, and the communication method includes, as shown in Figure 3, when the communication device 10 receives a request to perform a scan (Yes in step S11), a step (step S12) of determining whether there is a high probability of future data communication with the slave unit 100 based on the contents of transmission and reception performed within a predetermined period retrospectively from the time the request was received, which are stored in the storage unit 13, and a step (step S13) of controlling the execution of the scan based on the result of the determination.

[0090] For example, the present invention can be realized as a program that causes a computer (processor) to execute steps included in a communication method. Furthermore, the present invention can be realized as a non-temporary computer-readable recording medium, such as a CD-ROM, on which the program is recorded.

[0091] For example, if the present invention is implemented in a program (software), each step is executed by the program using hardware resources such as the CPU, memory, and input / output circuits of a computer. In other words, each step is executed by the CPU acquiring data from memory or input / output circuits, performing calculations, and outputting the calculation results to memory or input / output circuits.

[0092] In the above embodiment, each component included in the communication device 10 may be implemented by dedicated hardware or by executing a software program suitable for each component. Each component may also be implemented by a program execution unit such as a CPU or processor reading and executing a software program recorded on a recording medium such as a hard disk or semiconductor memory.

[0093] Some or all of the functions of the communication device 10 according to the above embodiment are typically implemented as an LSI, which is an integrated circuit. These may be individually integrated onto a single chip, or some or all of them may be integrated onto a single chip. Furthermore, the implementation of integrated circuits is not limited to LSIs; it may also be implemented using dedicated circuits or general-purpose processors. An FPGA (Field Programmable Gate Array), which can be programmed after LSI manufacturing, or a reconfigurable processor that allows for the reconfiguration of the connections and settings of circuit cells inside the LSI may also be used.

[0094] Furthermore, if advances in semiconductor technology or other derived technologies lead to the emergence of integrated circuit technologies that replace LSIs, then naturally, those technologies may be used to integrate each component included in the communication device 10 into an integrated circuit.

[0095] Furthermore, the present invention also includes forms obtained by applying various modifications to the embodiments that a person skilled in the art could conceive, and forms realized by arbitrarily combining the components and functions of each embodiment without departing from the spirit of the present invention. [Industrial applicability]

[0096] This invention can be applied to systems in which client devices communicate with each other via a master device (AP). [Explanation of Symbols]

[0097] 1. Communication System 10. Communication equipment 11 Communications Department 12 Control Unit 13 Storage section 100 Handset 200 Master Unit

Claims

1. A communication device that performs wireless communication via a master unit, A communication unit for performing wireless communication with a device connected to the master unit via the master unit, A storage unit that stores the contents of data transmitted and received with the aforementioned device, The system includes a control unit that, upon receiving a request to perform a scan, determines whether there is a high probability of future data communication with the device based on the contents of transmissions and receptions performed within a predetermined period retrospectively from the time the request was received, and controls the execution of the scan based on the result of the determination, If the control unit determines that there is a high probability of future data communication with the device, it will not perform a scan in response to the request. If the control unit determines that it is unlikely to communicate data with the device in the future, it will perform a foreground scan or a background scan for the request. If it determines that no transmission or reception has occurred within a predetermined period of time prior to the time the request was received, and a connection has been established with the device, it will perform a background scan for the request. Communication device.

2. If the control unit determines that the content of the transmission and reception performed within a predetermined period preceding the time the request was received contains information indicating that there is little likelihood of future data communication, it will perform a foreground scan in response to the request. The communication device according to claim 1.

3. If the control unit determines that there is a high probability of future data communication with the device, it instructs the requesting party to make the request again after a predetermined time. The communication device according to claim 1.

4. If the control unit determines that there is a high probability of future data communication with the device, it will, after a predetermined time, determine again, based on the contents of the transmission and reception stored in the storage unit, whether there is a high probability of future data communication with the device, and control the execution of the scan based on the result of that determination. The communication device according to claim 1.

5. The control unit determines that there is a high probability of future data communication with the device if the content of the transmission and reception performed within a predetermined period retrospectively from the time the request was received indicates transmission and reception of ARP (Address Resolution Protocol), TCP (Transmission Control Protocol), or DHCP (Dynamic Host Configuration Protocol). A communication device according to any one of claims 1, 3, or 4.

6. The control unit determines that there is a low probability of future data communication with the device if the content of the transmission and reception performed within a predetermined period retrospectively from the time the request was received indicates the transmission and reception of UDP (User Datagram Protocol), or if there is no content of the transmission and reception performed within a predetermined period retrospectively from the time the request was received. The communication device according to claim 1 or 2.

7. A communication method performed by a communication device that performs wireless communication via a master unit, The aforementioned communication device is A communication unit for performing wireless communication with a device connected to the master unit via the master unit, It includes a storage unit that stores the contents of data transmission and reception with the aforementioned device, In the aforementioned communication method, When the communication device receives a request to perform a scan, it takes the step of determining whether there is a high probability of future data communication with the device based on the contents of transmissions and receptions performed within a predetermined period of time retrospectively from the time the request was received, which are stored in the storage unit. The steps include controlling the execution of a scan on the device based on the result of the determination, In the control step described above, if it is determined that there is a high probability of future data communication with the device, the scan is not performed in response to the request. The control step, if it is determined that there is little likelihood of future data communication with the device, performs a foreground scan or background scan on the request, and if no transmission or reception has occurred within a predetermined period of time preceding the time the request was received, and a connection has been established with the device, performs a background scan on the request. Communication method.

8. A program for causing a computer to execute the communication method described in claim 7.

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