Communication device, communication control method, and program

Abstract

A communication device (1) (second equipment (1B)) comprises: a communication circuit that communicates with each of a first communication device (first equipment (1A)) and a second communication device (access point (2)); and a processing circuit that controls the communication circuit. The processing circuit determines whether or not direct communication with the first communication device in a first mode (LPI mode) is available on the basis of a reception result regarding a signal received by the communication circuit from the second communication device. In a case of determining that direct communication with the first communication device in the first mode is available, the processing circuit controls the communication circuit to carry out direct communication with the first communication device in the first mode. In a case of determining that direct communication with the first communication device in the first mode is unavailable, the processing circuit controls the processing circuit to carry out direct communication with the first communication device in a second mode (VLP mode) different from the first mode.

Description

Communication device, communication control method, and program

[0001] The present disclosure relates to a communication device or the like that communicates using radio waves.

[0002] For example, Patent Document 1 discloses a repeater for a wireless LAN (Local Area Network) that is equipped with a wireless communication circuit capable of communicating in the 6 GHz band.

[0003] JP 2023-97385 A

[0004] The present disclosure provides a communication device or the like that makes it easy to maintain direct communication with other communication devices.

[0005] A communication device according to one aspect of the present disclosure includes a communication circuit that communicates with each of a first communication device and a second communication device, and a processing circuit that controls the communication circuit. The processing circuit determines whether direct communication with the first communication device in a first mode is possible based on a reception result of a signal received by the communication circuit from the second communication device. If the processing circuit determines that the direct communication with the first communication device in the first mode is possible, it controls the communication circuit to perform the direct communication with the first communication device in the first mode. If the processing circuit determines that the direct communication with the first communication device in the first mode is not possible, it controls the communication circuit to perform the direct communication with the first communication device in a second mode different from the first mode.

[0006] A communication device according to one aspect of the present disclosure includes a communication circuit that communicates with each of a first communication device and a second communication device, and a processing circuit that controls the communication circuit. The processing circuit determines whether direct communication with the first communication device in a first mode is possible based on a reception result of a signal received by the communication circuit from the second communication device. If the processing circuit determines that the direct communication with the first communication device in the first mode is possible, the processing circuit controls the communication circuit to send to the first communication device an instruction to perform the direct communication with the communication circuit in the first mode. If the processing circuit determines that the direct communication with the first communication device in the first mode is not possible, the processing circuit controls the communication circuit to send to the first communication device an instruction to perform the direct communication with the communication circuit in a second mode different from the first mode.

[0007] A communication control method according to one aspect of the present disclosure communicates with each of a first communication device and a second communication device using a communication circuit. The communication control method determines whether direct communication with the first communication device in a first mode is possible based on a reception result of a signal received by the communication circuit from the second communication device. If the communication control method determines that the direct communication with the first communication device is possible in the first mode, the communication control method controls the communication circuit to perform the direct communication with the first communication device in the first mode. If the communication control method determines that the direct communication with the first communication device is not possible in the first mode, the communication control method controls the communication circuit to perform the direct communication with the first communication device in a second mode different from the first mode.

[0008] A communication control method according to one aspect of the present disclosure performs communication between a first communication device and a second communication device using a communication circuit. The communication control method determines whether direct communication with the first communication device in a first mode is possible based on a reception result of a signal received by the communication circuit from the second communication device. If the communication control method determines that the direct communication with the first communication device in the first mode is possible, the communication control method controls the communication circuit to send to the first communication device an instruction to perform the direct communication with the communication circuit in the first mode. If the communication control method determines that the direct communication with the first communication device in the first mode is not possible, the communication control method controls the communication circuit to send to the first communication device an instruction to perform the direct communication with the communication circuit in a second mode different from the first mode.

[0009] A program according to one aspect of the present disclosure causes one or more processors to execute the communication control method.

[0010] The communication device and the like according to the present disclosure has the advantage that direct communication with other communication devices can be easily maintained.

[0011] FIG. 1 is an explanatory diagram of a problem in communication between slave stations. FIG. 2 is an explanatory diagram of an overview of communication between slave stations using a communication device according to an embodiment. FIG. 3 is a block diagram showing an example of a configuration of a communication device according to an embodiment. FIG. 4 is a diagram showing an example of data stored in a memory of a communication device according to an embodiment. FIG. 5 is an explanatory diagram of an example of a basic operation using a communication device according to an embodiment. FIG. 6 is a sequence diagram showing an example of a basic operation using a communication device according to an embodiment. FIG. 7 is an explanatory diagram of a first example of operation using a communication device according to an embodiment. FIG. 8 is a sequence diagram showing a first example of operation using a communication device according to an embodiment. FIG. 9 is a flowchart showing an operation of a first device in the first example of operation using a communication device according to an embodiment. FIG. 10 is a flowchart showing an operation of a second device in the first example of operation using a communication device according to an embodiment. FIG. 11 is an explanatory diagram of a second example of operation using a communication device according to an embodiment. FIG. 12 is a sequence diagram showing a second example of operation using a communication device according to an embodiment. FIG. 13 is a flowchart showing an operation of a first device in the second example of operation using a communication device according to an embodiment. FIG. 14 is a flowchart showing an operation of a second device in the second example of operation using a communication device according to an embodiment. FIG. 15 is an explanatory diagram of a third operation example using the communication device according to the embodiment.

[0012] [1. Findings that Form the Basis of the Present Disclosure] First, the inventor's viewpoint will be explained below.

[0013] In recent years, the 6 GHz band (5925 MHz to 6425 MHz in Japan) has been opened up as a frequency band available for wireless LANs. However, at present, in order to share frequencies with existing systems such as fixed communication systems, satellite communication systems, and broadcast program relay systems, the use of the 6 GHz band for wireless LANs is limited to indoor use. Furthermore, at present, in Japan, the Radio Law Enforcement Regulations stipulate that communication between slave stations in LPI (Low Power Indoor) mode must operate within a range where the spectral density of the master station's signal strength is −95 dBm or less per 1 MHz, thereby restricting the locations where it can be used.

[0014] Here, when using the 6 GHz band in a wireless LAN, the Radio Law Enforcement Regulations stipulate that a communication device transmits radio waves in either LPI mode or VLP (Very Low Power) mode. LPI mode is a mode in which the radio wave transmission power is relatively high, and the maximum equivalent isotropic radiated power is set to be greater than 25 milliwatts and equal to or less than 200 milliwatts. As mentioned above, there are currently restrictions on the use of LPI mode in communication between slave stations. VLP mode is a mode in which the radio wave transmission power is lower than LPI mode, and the maximum equivalent isotropic radiated power is set to be equal to or less than 25 milliwatts, but there are no particular restrictions on its use in communication between slave stations.

[0015] Furthermore, communication between slave stations refers to establishing a peer-to-peer connection between two communication devices (slave stations) when the two communication devices are connected to a wireless LAN with an access point as the parent station, and communicating directly without going through the access point. Communication between slave stations is realized using a communication standard such as TDLS (Tunneled Direct Link Setup). Communication between slave stations is used, for example, when executing a mirroring function that displays an image displayed on one slave station, such as a smartphone, on another slave station, such as a television receiver.

[0016] As mentioned above, there are restrictions on communication between slave stations in LPI mode. Specifically, communication between two communication devices (slave stations) in LPI mode is permitted as long as they are located within a specified range of the access point (master station). Here, the specified range refers to the range in which the radio wave strength of the signal transmitted from the access point is equal to or greater than a threshold, and the threshold must be checked at least once every four seconds.

[0017] Here, the problem of communication between slave stations will be explained. Fig. 1 is an explanatory diagram of the problem of communication between slave stations. Fig. 1(a) shows a case where a first slave station 101 and a second slave station 102 are both present within a specified range A1 based on a master station 103, and Fig. 1(b) shows a case where one of the slave stations (here, the second slave station 102) has moved outside the specified range A1.

[0018] In the case shown in (a) of Figure 1, the first slave station 101 and the second slave station 102 are both within the specified range A1, so they can communicate with each other in the LPI mode. However, in the case shown in (b) of Figure 1, the second slave station 102 is outside the specified range A1, so the first slave station 101 and the second slave station 102 cannot communicate with each other in the LPI mode. In this case, the first slave station 101 and the second slave station 102 must stop their communication with each other and change to communication via the master station 103.

[0019] However, in this case, there is a problem that communication between the first slave station 101 and the second slave station 102 is temporarily interrupted when switching from inter-slave station communication to communication via the master station 103. In addition, in this case, there is a problem that the communication speed (e.g., bits per second) of communication between the first slave station 101 and the second slave station 102 becomes lower than the communication speed in inter-slave station communication, and delays during transmission also increase.

[0020] In view of the above, the inventors have come up with the present disclosure.

[0021] Hereinafter, the embodiments will be described in detail with reference to the drawings. Note that the embodiments described below are all comprehensive or specific examples. The numerical values, shapes, materials, components, component placement and connection forms, steps, step order, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Furthermore, among the components in the following embodiments, components not recited in independent claims will be described as optional components.

[0022] It should be noted that the drawings are schematic diagrams and are not necessarily strict illustrations. In addition, in the drawings, substantially the same components are denoted by the same reference numerals, and overlapping descriptions may be omitted or simplified.

[0023] (Embodiment) [2. Overview] First, an overview of communication between slave stations using a communication device 1 according to an embodiment will be described with reference to FIG. 2. FIG. 2 is an explanatory diagram of the overview of communication between slave stations using a communication device 1 according to an embodiment. In the following description, a first device 1A, a second device 1B, and an access point 2 appear, but either the first device 1A or the second device 1B will be referred to as the communication device 1. Furthermore, for example, when either the first device 1A or the first device 1B is referred to as the "communication device 1," the other device may be referred to as the "first communication device," and the access point 2 as the "second communication device." In the embodiment, the second device 1B will be referred to as the "communication device 1," the first device 1A as the "first communication device," and the access point 2 as the "second communication device."

[0024] In this embodiment, the second device 1B is a portable television receiver, and the first device 1A is a tuner. The tuner is, for example, a device that receives television broadcasts and transmits the received television broadcasts to the portable television receiver via wireless communication. Note that the first device 1A and the second device 1B are not limited to these devices, and may be any devices that are capable of inter-slave station communication.

[0025] (a) of Figure 2 shows a case where the first device 1A and the second device 1B are both present within a specified range A1 based on the access point 2, and (b) of Figure 2 shows a case where one of the devices (here, the second device 1B) has moved outside the specified range A1.

[0026] In the case shown in Fig. 2(a), the first device 1A and the second device 1B are both within the specified range A1, so communication between the slave stations in the LPI mode is possible. On the other hand, in the case shown in Fig. 2(b), the second device 1B is outside the specified range A1, so communication between the slave stations in the LPI mode is not possible between the first device 1A and the second device 1B.

[0027] Therefore, when the second device 1B, which is the communication device 1, moves outside the specified range A1, it changes from the LPI mode to the VLP mode. As already mentioned, the VLP mode does not have any particular limitations on the location that can be used for communication between slave stations, so it is possible to maintain communication between slave stations between the first device 1A and the second device 1B.

[0028] [3. Configuration] The configuration of a communication device 1 according to an embodiment will be described below with reference to Fig. 3. Fig. 3 is a block diagram showing an example configuration of a communication device 1 according to an embodiment. Both a first device 1A and a second device 1B have the configuration of the communication device 1 described below. Here, the description will be given assuming that the communication device 1 is the second device 1B. The communication device 1 includes a communication circuit 11, a processing circuit 12, and a memory 13.

[0029] The communication circuit 11 is a circuit that communicates with each of a first communication device (here, the first device 1A) and a second communication device (here, the access point 2). The communication circuit 11 has an antenna 111, an RF-SW 112, a receiving circuit 113, a transmitting circuit 114, and an RF power control circuit 115.

[0030] When the antenna 111 receives radio waves in a predetermined frequency band (here, the 6 GHz band), it converts the radio waves into electrical signals and outputs the converted electrical signals to a receiving circuit 113 via an RF switch (hereinafter referred to as "RF-SW") 112. The antenna 111 also converts electrical signals received from a transmitting circuit 114 via the RF-SW 112 into radio waves in a predetermined frequency band and outputs the converted radio waves to the outside. Note that the antenna 111 is not limited to the predetermined frequency band and may also be capable of transmitting and receiving radio waves in other frequency bands (for example, the 2.4 GHz band or the 5 GHz band).

[0031] The RF-SW 112 is a switch that switches the path of a high-frequency signal. When receiving radio waves, the RF-SW 112 switches to a path that connects the antenna 111 and the receiving circuit 113. When transmitting radio waves, the RF-SW 112 switches to a path that connects the antenna 111 and the transmitting circuit 114.

[0032] The receiving circuit 113 demodulates the electrical signal output from the antenna 111 via the RF-SW 112, and outputs the demodulated electrical signal (hereinafter also referred to as the "received signal") to the processing circuit 12. In this embodiment, the receiving circuit 113 employs, for example, a direct conversion system or a superheterodyne system. The receiving circuit 113 also has an RF detector, measures the RSSI (Received Signal Strength Indicator) value of the received signal, and outputs the measured RSSI value to the processing circuit 12.

[0033] The transmission circuit 114 modulates and amplifies the electrical signal (hereinafter also referred to as the "transmission signal") output from the processing circuit 12, and outputs the modulated and amplified electrical signal to the antenna 111 via the RF-SW 112. In the embodiment, the modulation method is a multi-carrier modulation method such as the Orthogonal Frequency-Division Multiplexing (OFDM) method.

[0034] The RF power control circuit 115 is a circuit that controls the amplifier included in the transmission circuit 114, and controls the transmission power of the radio waves output from the antenna 111. In the embodiment, the RF power control circuit 115 controls the transmission power in accordance with instructions from the processing circuit 12. Specifically, when the communication device 1 is operated in the LPI mode (first mode), the RF power control circuit 115 controls the amplifier so that the transmission power of the radio waves output from the antenna 111 becomes transmission power corresponding to the LPI mode. Furthermore, when the communication device 1 is operated in the VLP mode (second mode), the RF power control circuit 115 controls the amplifier so that the transmission power of the radio waves output from the antenna 111 becomes transmission power corresponding to the VLP mode.

[0035] The processing circuit 12 is a baseband circuit that performs information processing based on a received signal output from the receiving circuit 113 and information processing for outputting a transmission signal to the transmitting circuit 114. The processing circuit 12 is, for example, an MCU (Micro Controller Unit). The above-mentioned information processing is realized by the processing circuit 12 executing a computer program stored in the memory 13.

[0036] The memory 13 is a storage device that stores computer programs executed by the processing circuitry 12, information necessary for implementing various functions, etc. The memory 13 is realized by, for example, a semiconductor memory, etc. Note that the memory 13 may be realized as an internal memory of the processing circuitry 12, rather than as an external memory of the processing circuitry 12.

[0037] Here, the processing circuit 12 executes the following two processes every time the communication circuit 11 receives a signal from the second communication device (access point 2).

[0038] First, the processing circuit 12 executes a process (hereinafter also referred to as a "determination process") to determine whether the communication device 1 (second device 1B) is capable of direct communication (communication between slave stations) in the first mode (LPI mode) with the first communication device (first device 1A) based on a reception result of a signal (received signal) received by the communication circuit 11 from the second communication device (access point 2). The determination process corresponds to a process of determining whether the communication device 1 (second device 1B) is present within the specified range A1.

[0039] Specifically, the processing circuit 12 compares the RSSI value of the signal transmitted from the access point 2, which is included in the received signal acquired from the receiving circuit 113, with a threshold value stored in advance in the memory 13. If the RSSI value is equal to or greater than the threshold value, the processing circuit 12 determines that direct communication is possible in the first mode, and if the RSSI value is less than the threshold value, the processing circuit 12 determines that direct communication is not possible in the first mode. In other words, if the radio wave intensity of the signal received by the communication circuit 11 from the second communication device (access point 2) is below the threshold value, the processing circuit 12 determines that direct communication (communication between slave stations) with the first communication device (first device 1A) in the first mode (LPI mode) is not possible. Here, the threshold value is, for example, -95 dBm / MHz.

[0040] In this embodiment, the memory 13 stores a threshold for each of five types of occupied frequency bandwidth used in the OFDM modulation method. The processing circuit 12 then compares the RSSI value with the threshold corresponding to the occupied frequency bandwidth used. For example, when the occupied frequency bandwidth is 20 MHz, the threshold is −82 dBm. For example, when the occupied frequency bandwidth is 40 MHz, the threshold is −79 dBm. For example, when the occupied frequency bandwidth is 80 MHz, the threshold is −76 dBm. For example, when the occupied frequency bandwidth is 160 MHz, the threshold is −73 dBm. For example, when the occupied frequency bandwidth is 320 MHz, the threshold is −70 dBm.

[0041] Second, the processing circuit 12 executes a process (hereinafter also referred to as a "mode determination process") to determine the operation mode of the communication device 1 based on the determination result of the determination process. Specifically, if the processing circuit 12 determines in the determination process that the communication device 1 (second device 1B) is capable of direct communication (inter-slave station communication) with the first communication device (first device 1A) in the first mode (LPI mode), the processing circuit 12 controls the communication circuit 11 to perform direct communication with the first communication device in the first mode (i.e., determines the operation mode of the communication device 1 to be the first mode). More specifically, the processing circuit 12 refers to data pre-stored in the memory 13, reads data indicating a gain corresponding to the first mode, and outputs the data to the RF power control circuit 115. As a result, the RF power control circuit 115 controls the amplifier so that the transmission power of the radio waves output from the antenna 111 corresponds to the transmission power corresponding to the first mode.

[0042] Furthermore, if the processing circuitry 12 determines in the determination process that the communication device 1 cannot communicate directly with the first communication device in the first mode, the processing circuitry 12 controls the communication circuitry 11 to communicate directly with the first communication device in a second mode (VLP mode) different from the first mode (i.e., determines the operation mode of the communication device 1 to be the second mode). Specifically, the processing circuitry 12 refers to data pre-stored in the memory 13, reads data indicating a gain corresponding to the second mode, and outputs the data to the RF power control circuit 115. As a result, the RF power control circuit 115 controls the amplifier so that the transmission power of the radio waves output from the antenna 111 is the transmission power corresponding to the second mode.

[0043] That is, the processing circuit 12 measures the RSSI value of the beacon signal transmitted from the access point 2 and determines whether the communication device 1 is present within the specified range A1 based on the measured RSSI value. If the RSSI value is equal to or greater than a threshold, the processing circuit 12 determines that the communication device 1 is present within the specified range A1 and sets the operation mode to LPI mode (first mode). If the RSSI value is below the threshold, the processing circuit 12 determines that the communication device 1 is present outside the specified range A1 and changes the operation mode from LPI mode (first mode) to VLP mode (second mode).

[0044] If the determination result is the same as the previous determination result, the processing circuitry 12 does not output data indicating the gain to the RF power control circuit 115. In this case, the operation mode of the communication device 1 is not changed and is maintained.

[0045] Fig. 4 is a diagram showing an example of data stored in the memory 13 of the communication device 1 according to the embodiment. Fig. 4(a) shows an example of data referenced by the processing circuitry 12, and Fig. 4(b) shows another example of data referenced by the processing circuitry 12. In the embodiment, the data stored in the memory 13 is either the data shown in Fig. 4(a) or the data shown in Fig. 4(b).

[0046] 4A, the processing circuitry 12 reads data indicating the gain corresponding to the second mode by changing the reference in a file (here, "Table A.txt") stored in the memory 13. Specifically, the processing circuitry 12 changes the reference from [JP-LPI], in which the gain corresponding to the first mode is described, to [JP-VLP], in which the gain corresponding to the second mode is described.

[0047] 4B, the processing circuitry 12 reads data indicating gains corresponding to the second mode by changing the reference destination from a file (here, "Table A.txt") stored in the memory 13 to another file (here, "Table B.txt"). Specifically, the processing circuitry 12 changes the reference destination from "Table A.txt" including [JP-LPI] in which gains corresponding to the first mode are described to "Table B.txt" including [JP-VLP] in which gains corresponding to the second mode are described.

[0048] [4. Operation] An example of operation using the communication device 1 according to the embodiment, that is, an example of a communication control method, will be described below.

[0049] [4-1. Example of Basic Operation] An example of basic operation using the communication device 1 according to the embodiment will be described below with reference to Fig. 5 and Fig. 6. Fig. 5 is an explanatory diagram of an example of basic operation using the communication device 1 according to the embodiment. Fig. 6 is a sequence diagram showing an example of basic operation using the communication device 1 according to the embodiment.

[0050] First, as shown in (a) of Figure 5 and step S101 of Figure 6, a process is executed to connect the first device 1A (first communication device) and the second device 1B (communication device 1) to a wireless LAN by connecting them to an access point 2 (second communication device). This process can be executed, for example, by a user performing a predetermined operation on each of the first device 1A and the second device 1B. As a result, the first device 1A and the second device 1B are connected to the access point 2 as slave stations, with the access point 2 acting as a master station.

[0051] Next, as shown in (b) of Fig. 5 and steps S102 and S103 of Fig. 6, processing is executed for performing inter-slave communication between the first device 1A and the second device 1B in the LPI mode. In this embodiment, inter-slave communication between the first device 1A and the second device 1B is performed using TDLS.

[0052] First, in step S102, the first device 1A transmits a search packet called a "TDLS Discovery request" ("request" shown in FIG. 6) to another slave station (here, the second device 1B) via the access point 2. Upon receiving the search packet, the second device 1B transmits a response packet called a "TDLS Discovery response" ("response" shown in FIG. 6) to the sender of the search packet (here, the first device 1A). This enables the first device 1A to discover the second device 1B, which may be a target of inter-slave station communication by TDLS. Note that step S102 is executed periodically regardless of whether the first device 1A and the second device 1B are performing inter-slave station communication.

[0053] Next, in step S103, the first device 1A transmits a connection request packet called a "TDLS Setup request" ("Setup request" shown in FIG. 6) to the second device 1B. Upon receiving the connection request packet, the second device 1B transmits a packet indicating acceptance of the connection request ("Accept" shown in FIG. 6) to the sender of the connection request packet (here, the first device 1A). Thereby, a TDLS connection is established between the first device 1A and the second device 1B, and communication between the slave stations of the first device 1A and the second device 1B in the LPI mode (first mode) is initiated.

[0054] 6, the first device 1A transmits a packet directly to the second device 1B in LPI mode without going through the access point 2, and the second device 1B returns an ACK (Acknowledgement) of the packet directly to the first device 1A in LPI mode without going through the access point 2. This repeats the process, whereby data is transmitted and received between the first device 1A and the second device 1B by inter-slave station communication.

[0055] Here, the first device 1A and the second device 1B periodically (e.g., every few seconds) perform a determination process. Specifically, each of the first device 1A and the second device 1B measures the RSSI value of a beacon signal periodically transmitted from the access point 2 and determines whether or not it is present within the specified range A1 based on the measured RSSI value. The first device 1A may, for example, measure the RSSI value of a response packet periodically transmitted from the second device 1B via the access point 2 and determine whether or not it is present within the specified range A1 based on the measured RSSI value. The second device 1B may, for example, measure the RSSI value of a search packet periodically transmitted from the first device 1A via the access point 2 and determine whether or not it is present within the specified range A1 based on the measured RSSI value.

[0056] 5(c) and step S105 in FIG. 6, if the second device 1B moves outside the specified range A1, for example, because the user carries the second device 1B, the second device 1B (the processing circuit 12 of the communication device 1) determines that it is outside the specified range A1. Then, as shown in FIG. 5(c) and step S106 in FIG. 6, the second device 1B changes its operating mode from the LPI mode (first mode) to the VLP mode (second mode) through a mode determination process. This allows communication between the slave stations of the first device 1A and the second device 1B to continue uninterrupted thereafter.

[0057] 6, the first device 1A transmits a packet directly to the second device 1B in the LPI mode without going through the access point 2, and the second device 1B returns an ACK for the packet directly to the first device 1A in the VLP mode without going through the access point 2. This repeats the process, whereby data is transmitted and received between the first device 1A and the second device 1B by inter-slave station communication.

[0058] [4-2. First Operation Example] A first operation example using the communication device 1 according to the embodiment will be described below with reference to Figs. 7, 8, 9, and 10. Fig. 7 is an explanatory diagram of the first operation example using the communication device 1 according to the embodiment. Fig. 8 is a sequence diagram showing the first operation example using the communication device 1 according to the embodiment. Fig. 9 is a flowchart showing the operation of the first device 1A (first communication device) in the first operation example using the communication device 1 according to the embodiment. Fig. 10 is a flowchart showing the operation of the second device 1B (communication device 1) in the first operation example using the communication device 1 according to the embodiment.

[0059] In the first operation example, steps S201 to S204 in Fig. 8 are the same as steps S101 to S104 in Fig. 6 of the basic operation example, and therefore will not be described here. The following description begins with the start of inter-substation communication between the first device 1A (first communication device) and the second device 1B (communication device 1). After the inter-substation communication starts, the first device 1A repeats steps S301 to S307 in Fig. 9 until the inter-substation communication is stopped. Furthermore, after the inter-substation communication starts, the second device 1B repeats steps S401 to S412 in Fig. 10 until the inter-substation communication is stopped.

[0060] The first device 1A acquires wireless information (step S301 in FIG. 9). Similarly, the second device 1B acquires wireless information (step S401 in FIG. 10).

[0061] Here, the wireless information acquired by the first device 1A includes an RSSI value of a signal transmitted from the access point 2 to the second device 1B and information related to the communication quality of the communication between the slave stations. The information related to the communication quality includes, for example, a measurement result of the RSSI value of the signal transmitted from the second device 1B, an MCS (Modulation and Coding Scheme), and the degree of data transmission errors such as a packet loss rate.

[0062] The first device 1A can acquire the RSSI value of the signal transmitted from the access point 2 to the second device 1B, which is included in the response packet, by receiving the response packet periodically transmitted via the access point 2. Furthermore, the first device 1A can acquire information regarding the communication quality of the inter-substation communication by receiving an ACK received in the inter-substation communication with the second device 1B.

[0063] Similarly, the wireless information acquired by the second device 1B includes the RSSI value of the signal transmitted from the access point 2 to the first device 1A and information related to the communication quality of the communication between the slave stations. The information related to the communication quality includes, for example, the measurement result of the RSSI value of the signal transmitted from the first device 1A, the MCS, and the degree of data transmission errors such as the packet loss rate.

[0064] The second device 1B can acquire the RSSI value of the signal transmitted from the access point 2 to the first device 1A, which is included in the search packet, by receiving the search packet that is periodically transmitted via the access point 2. Furthermore, the second device 1B can acquire information regarding the communication quality of the inter-slave station communication by receiving a packet received in the inter-slave station communication with the first device 1A.

[0065] 7 and 8 , if the second device 1B moves outside the specified range A1, for example, because the user carries the second device 1B, the second device 1B (the processing circuit 12 of the communication device 1) determines that it is outside the specified range A1 (step S402: Yes in FIG. 10 ). Note that while the second device 1B determines that it is not outside the specified range A1, i.e., that it is within the specified range A1 (step S402: No in FIG. 10 and step S410: No in FIG. 10 ), it continues communication between slave stations in the LPI mode (first mode) (step S412 in FIG. 10 ).

[0066] If the second device 1B is outside the specified range A1 and moves from within the specified range A1 to the outside (step S403 in FIG. 10: Yes), it notifies the first device 1A that it is outside the specified range A1, as shown in step S206 in FIG. 8 and step S404 in FIG. 10. On the other hand, if the first device 1B continues to be outside the specified range A1 (step S403 in FIG. 10: No), it continues the inter-slave communication between the first device 1A and the second device 1B without interruption (step S408 in FIG. 10).

[0067] When the first device 1A receives the notification from the second device 1B (step S302 in FIG. 9 ), it executes a process for determining a communication mode. Specifically, the first device 1A determines whether communication between the local stations or communication via the access point 2 is better by referring to information about communication quality included in the wireless information (step S303 in FIG. 9 ). Here, the first device 1A compares the communication quality of communication between the local stations when the operation mode of the second device 1B is changed to the VLP mode with the communication quality of communication via the access point 2. These communication qualities may be estimated values ​​assuming that the operation mode of the second device 1B is changed to the VLP mode, or may be actual measured values ​​when the operation mode of the second device 1B is actually changed to the VLP mode.

[0068] If the first device 1A determines that the communication quality between the local stations is better (step S303 in FIG. 9 : Yes), it instructs the second device 1B to continue the communication between the local stations (step S304 in FIG. 9 ). When the second device 1B receives the instruction from the first device 1A (step S405 in FIG. 10 ), since the instruction is to continue the communication between the local stations (step S406 in FIG. 10 : Yes), it performs a mode determination process to change the operating mode from the LPI mode (first mode) to the VLP mode (second mode) (step S407 in FIG. 10 ). This allows the communication between the local stations between the first device 1A and the second device 1B to continue without interruption (step S305 in FIG. 9 and step S408 in FIG. 10 ).

[0069] On the other hand, if the first device 1A determines that the communication quality of the inter-slave station communication is not better (step S303: No in FIG. 9 ), it instructs the second device 1B to stop the inter-slave station communication and change to communication via access point 2 (step S306 in FIG. 9 ). Then, the first device 1A stops the inter-slave station communication and starts communication via access point 2 (step S307 in FIG. 9 ). When the second device 1B receives the instruction from the first device 1A (step S405 in FIG. 10 ), the instruction is to change to communication via access point 2 (step S406 in FIG. 10 : No), so it stops the inter-slave station communication and starts communication via access point 2 (step S409 in FIG. 10 ). As a result, from then on, the first device 1A and the second device 1B communicate via access point 2, as shown in FIG. 7 .

[0070] Thereafter, as shown in step S207 of FIG. 8, the first device 1A transmits a packet to the second device 1B in LPI mode via the access point 2, and the second device 1B returns an ACK for the packet to the first device 1A in LPI mode via the access point 2, and this process is repeated.

[0071] Thereafter, if the second device 1B moves into the specified range A1, for example, by carrying the second device 1B, the second device 1B determines that it is within the specified range A1 (step S402 in FIG. 10 : No) and that it has moved from outside the specified range A1 into the specified range A1 (step S410 in FIG. 10 : Yes). Then, the second device 1B changes its operating mode from the VLP mode (second mode) to the LPI mode (first mode) through a mode determination process (step S411 in FIG. 10 ). This allows the communication between the slave stations of the first device 1A and the second device 1B to continue uninterrupted (step S412 in FIG. 10 ).

[0072] In the first operation example, the first device 1A executes the process for determining the communication mode, but the second device 1B may execute the process for determining the communication mode. In this case, when the second device 1B determines that it is outside the specified range A1, it executes the process for determining the communication mode and instructs the first device 1A based on the result.

[0073] As described above, in the first operation example, if the processing circuit 12 determines that direct communication with the first communication device (here, the first device 1A) is not possible in the first mode (here, LPI mode), it causes the communication device 1 and the first communication device to execute a process of determining whether the communication quality is better between direct communication or communication via the second communication device (here, access point 2), and if it determines that the communication quality via the second communication device is good, a process of communicating with the first communication device via the second communication device.

[0074] [4-3. Second Operation Example] A second operation example using the communication device 1 according to the embodiment will be described below with reference to Figs. 11, 12, 13, and 14. Fig. 11 is an explanatory diagram of the second operation example using the communication device 1 according to the embodiment. Fig. 12 is a sequence diagram showing the second operation example using the communication device 1 according to the embodiment. Fig. 13 is a flowchart showing the operation of the first device 1A (first communication device) in the second operation example using the communication device 1 according to the embodiment. Fig. 14 is a flowchart showing the operation of the second device 1B (communication device 1) in the second operation example using the communication device 1 according to the embodiment.

[0075] In the second operation example, steps S502 to S508 in Fig. 12 are the same as steps S101 to S107 in Fig. 6 of the basic operation example, and therefore will not be described here. In step S502, the second device 1B first executes a process of instructing the first device 1A to connect to the access point 2, and the process thereafter is the same as step S101. Furthermore, steps S601 to S607 in Fig. 13 are the same as steps S301 to S307 in Fig. 9 of the first operation example, and therefore will not be described here. Furthermore, steps S701 to S712 in Fig. 14 are the same as steps S401 to S412 in Fig. 10 of the first operation example, and therefore will not be described here. After communication between the slave stations is initiated, the first device 1A repeats steps S601 to S610 in Fig. 13 until communication between the slave stations is stopped. After the inter-slave station communication is started, the second device 1B repeats steps S701 to S716 in FIG. 14 until the inter-slave station communication is stopped.

[0076] In the second operation example, as shown in step S501 of FIG. 12 , before communication between the first device 1A (first communication device) and the second device 1B (communication device 1) is initiated, the first device 1A and the second device 1B are connected as a parent-child device. Specifically, the first device 1A sends a connection request to the second device 1B, and the second device 1B accepts the connection request, thereby enabling parent-child communication with the first device 1A as the parent station and the second device 1B as the child station. Parent-child communication refers to establishing a peer-to-peer connection between the two communication devices without connecting to a wireless LAN with the access point 2 as the parent station, and communicating directly without going through the access point 2. In other words, in parent-child communication, the first device 1A and the second device 1B transmit and receive data without being connected to a wide area network such as the Internet.

[0077] The following description begins from the point at which the second device 1B moves outside the specified range A1, causing the operating mode to change from LPI mode (first mode) to VLP mode (second mode), and communication between the slave stations continues.

[0078] 12 and 11, when the second device 1B moves out of the communication range A2 of the access point 2, for example, because the user carries the second device 1B, the second device 1B (the processing circuit 12 of the communication device 1) determines that it is out of the range of the access point 2, that is, that it cannot communicate with the access point 2 (step S713 in FIG. 14: Yes). Note that the second device 1B continues communication between slave stations in the VLP mode while it determines that it is within the communication range A2 (step S713 in FIG. 14: No).

[0079] As a result, as shown in step S510 of FIG. 12 , the first device 1A and the second device 1B reconnect as a parent and child device. Specifically, the second device 1B notifies the first device 1A that it is out of range of the access point 2 (step S714 of FIG. 14 ). Upon receiving the notification from the second device 1B (step S608 of FIG. 13 ), the first device 1A stops communication between slave stations, changes itself to the master station, and reconnects as a parent and child device with the second device 1B by performing the same process as in step S501 (step S609 of FIG. 13 ). Similarly, the second device 1B stops communication between slave stations and performs the same process as in step S501 to reconnect as a parent and child device with the first device 1A, which is the master station (step S715 of FIG. 14 ). As a result, parent-child communication in the LPI mode is started with the first device 1A as the parent station and the second device 1B as the child station (step S610 in FIG. 13 and step S716 in FIG. 14).

[0080] Thereafter, as shown in step S511 of FIG. 12, with neither the first device 1A nor the second device 1B connected to the access point 2, the first device 1A transmits a packet to the second device 1B in LPI mode, and the second device 1B returns an ACK for the packet to the first device 1A in LPI mode. This process is repeated.

[0081] Thereafter, as shown in step S512 of Fig. 12 , if the second device 1B moves from outside the specified range A1 to within the communication range A2, for example, by the user carrying the second device 1B, the second device 1B determines that it is within the range of the access point 2 but outside the specified range A1. Then, as shown in step S513 of Fig. 12 , the second device 1B notifies the first device 1A that it is outside the specified range A1. Here, the second device 1B changes its operating mode from the LPI mode to the VLP mode and notifies the first device 1A of this.

[0082] 12 , when the first device 1A receives the notification from the second device 1B, it executes a process for determining the communication mode, similar to the first operation example. Here, the first device 1A determines that communication between slave stations has better communication quality, and instructs the second device 1B to connect to the access point 2. Then, the first device 1A and the second device 1B each execute a process for connecting to the access point 2. As a result, the first device 1A and the second device 1B are each connected to the access point 2 as a slave station, with the access point 2 as the master station.

[0083] Next, the first device 1A transmits a connection request packet to the second device 1B. Upon receiving the connection request packet, the second device 1B changes its operating mode from LPI mode to VLP mode and transmits a packet indicating acceptance of the connection request to the first device 1A. This establishes a TDLS connection between the first device 1A and the second device 1B, and communication between the slave stations of the first device 1A and the second device 1B begins.

[0084] 12, the first device 1A transmits a packet directly to the second device 1B in LPI mode without going through the access point 2, and the second device 1B returns an ACK for the packet directly to the first device 1A in VLP mode without going through the access point 2. This repeats the process, whereby data is transmitted and received between the first device 1A and the second device 1B by inter-slave station communication.

[0085] As described above, in the second operation example, when the first communication device (here, the first device 1A) cannot communicate with the second communication device (here, the access point 2), the processing circuit 12 causes the communication device 1 and the first communication device to execute a process of parent-child communication in which one of the communication device 1 and the first communication device is the parent station and the other is the child station.

[0086] [4-4. Third Operation Example] A third operation example using the communication device 1 according to the embodiment will be described below with reference to Fig. 15. Fig. 15 is an explanatory diagram of the third operation example using the communication device 1 according to the embodiment. In Fig. 15, the solid arrows represent radio waves in the 6 GHz band (first frequency band), and the dotted arrows represent radio waves in the 5 GHz band (second frequency band).

[0087] 15, in the third operation example, the first device 1A (first communication device), the second device 1B (communication device 1), and the access point 2 (second communication device) not only transmit and receive radio waves in the 6 GHz band but also transmit and receive radio waves in the 5 GHz band with each other. The third operation example can be realized when the first device 1A, the second device 1B, and the access point 2 support a predetermined wireless communication standard such as Wi-Fi CERTIFIED 7 (registered trademark).

[0088] In the third operation example, with respect to the 6 GHz band, the operations of the first device 1A, the second device 1B, and the access point 2 are the same as those in the basic operation example. That is, as shown in (a) of FIG. 15 , when the second device 1B is within the specified range A1, the second device 1B continues communication between the slave stations in the LPI mode (first mode). Then, as shown in (b) of FIG. 15 , when the second device 1B moves outside the specified range A1, the second device 1B changes the operation mode from the LPI mode (first mode) to the VLP mode (second mode) and continues communication between the slave stations. On the other hand, in the third operation example, with respect to the 5 GHz band, the first device 1A, the second device 1B, and the access point 2 transmit and receive packets in the same manner as with radio waves in the 6 GHz band, regardless of whether the second device 1B is outside the specified range A1.

[0089] As described above, in the third operation example, the processing circuit 12 controls the communication circuit 11 to perform both communication with each of the first communication device (here, the first device 1A) and the second communication device (here, the access point 2) in a first frequency band (here, the 6 GHz band) using a first mode (here, the LPI mode) and a second mode (here, the VLP mode), and communication with each of the first communication device and the second communication device in a second frequency band (here, the 5 GHz band or the 2.4 GHz band) different from the first frequency band.

[0090] [4-5. Fourth Operation Example] A fourth operation example using the communication device 1 according to the embodiment will be described below. In the fourth operation example, when the second device 1B (the processing circuit 12 of the communication device 1) determines that it is located outside the specified range A1 and changes its operation mode from the LPI mode (first mode) to the VLP mode (second mode), it outputs information (hereinafter also referred to as "notification information") to the outside that it is located outside the specified range A1, in other words, that the radio wave strength of the signal from the access point 2 is weak. The notification information may include, for example, information suggesting that the second device 1B be moved into the specified range A1.

[0091] For example, if the second device 1B has a display, it outputs the notification information to the outside by displaying it on the display. Alternatively, if the second device 1B has a speaker, it outputs the notification information to the outside by outputting the notification information as audio from the speaker. Alternatively, if the first device 1A has a display or a speaker, the second device 1B transmits an instruction to output the notification information to the first device 1A. In this case, the first device 1A outputs the notification information to the outside via the display or speaker.

[0092] When the second device 1B determines that it is within the specified range A1 but near the boundary of the specified range A1, the second device 1B may output notification information to the outside, indicating that the radio wave intensity of the signal from the access point 2 is weak. In this case, the notification information may include information warning the second device 1B not to move any further away from the access point 2.

[0093] As described above, in the fourth operation example, when the processing circuit 12 determines that the radio wave strength of a signal from a second communication device (here, access point 2) received by either the communication device 1 or the first communication device (here, first device 1A) is within a predetermined range, it causes either the communication device 1 or the first communication device to output information indicating that the radio wave strength is weak to the outside.

[0094] [4-6. Fifth Operation Example] The following describes a fifth operation example using the communication device 1 according to the embodiment. In the fifth operation example, the second device 1B (the processing circuit 12 of the communication device 1) further determines whether either itself or the first device 1A (first communication device) is outdoors.

[0095] For example, if the second device 1B has an illuminance sensor, it determines that the second device 1B is exposed to sunlight, i.e., is outdoors, when the detected illuminance is greater than a predetermined illuminance (e.g., the general illuminance of lighting). Note that if the first device 1A has an illuminance sensor, the second device 1B can determine whether the first device 1A is outdoors by obtaining the detection result of the illuminance sensor.

[0096] Furthermore, for example, if the second device 1B has an optical sensor, it analyzes the spectrum of the detected light, and if the light is sunlight, it determines that the second device 1B is exposed to sunlight, i.e., is outdoors. Note that if the first device 1A has an optical sensor, the second device 1B can determine whether the first device 1A is outdoors by obtaining the detection result of the optical sensor.

[0097] Furthermore, for example, if the second device 1B has a positioning circuit such as a GPS (Global Positioning System) circuit, it determines whether it is outdoors based on the positioning results. Note that if the first device 1A has a positioning circuit, it can determine whether the first device 1A is outdoors by acquiring the positioning results of the positioning circuit.

[0098] Then, when the second device 1B determines that either itself or the first device 1A is outdoors, it changes its operating mode from LPI mode (first mode) to VLP mode (second mode) regardless of whether it is outside the specified range A1 or not.

[0099] As described above, in the fifth operation example, the processing circuit 12 further determines whether either the communication device 1 or the first communication device (here, the first device 1A) is outdoors. If the processing circuit 12 determines that either the communication device 1 or the first communication device is outdoors, the processing circuit 12 controls the communication circuit 11 to communicate directly with the first communication device in a second mode (here, the VLP mode) different from the first mode (here, the LPI mode).

[0100] [5. Effects, etc.] Advantages of the communication device 1 (communication control method) according to the embodiment will be described below. As described above, when the processing circuit 12 of the communication device 1 (here, the second device 1B) determines that direct communication with the first communication device (here, the first device 1A) is not possible in the first mode (here, the LPI mode), the processing circuit 12 controls the communication circuit 11 to communicate directly with the first communication device in a second mode (e.g., the VLP mode) different from the first mode. Therefore, the communication device 1 can continue inter-slave station communication without temporarily interrupting the inter-slave station communication. In other words, the communication device 1 has the advantage of easily maintaining direct communication with other communication devices.

[0101] Therefore, the embodiment can solve the problem of temporary interruption of communication between slave stations as described in [1. Knowledge forming the basis of the present disclosure]. Furthermore, the embodiment has an advantage that, when the communication speed in VLP mode is faster than the communication speed via access point 2, it is easier to suppress a decrease in the communication speed of communication between communication device 1 and the first communication device compared to when switching to communication via access point 2.

[0102] 6. Other Embodiments Although the embodiments have been described above, the present disclosure is not limited to the above-described embodiments.

[0103] In the above embodiment, the communication device 1 changes its own operation mode when it determines that it is outside the specified range A1, but this is not limited to this. For example, when the communication device 1 determines that the first communication device, which is the other party in inter-slave communication, is outside the specified range A1, the communication device 1 may instruct the first communication device to change its operation mode.

[0104] That is, the communication device 1 includes a communication circuit 11 that communicates with each of a first communication device (e.g., second device 1B) and a second communication device (e.g., access point 2), and a processing circuit 12 that controls the communication circuit 11. The processing circuit 12 determines whether direct communication with the first communication device is possible in a first mode (e.g., LPI mode) based on a reception result of a signal received by the communication circuit 11 from the second communication device. If the processing circuit 12 determines that direct communication with the first communication device is possible in the first mode, it controls the communication circuit 11 to send an instruction to the first communication device to communicate directly with the communication circuit 11 in the first mode. If the processing circuit 12 determines that direct communication with the first communication device is not possible in the first mode, it controls the communication circuit 11 to send an instruction to the first communication device to communicate directly with the communication circuit 11 in a second mode (e.g., VLP mode) different from the first mode.

[0105] The order of the processes described in the above embodiments is merely an example. The order of multiple processes may be changed, or multiple processes may be executed in parallel. Furthermore, a process executed by a specific processing unit may be executed by another processing unit. Furthermore, part of the digital signal processing described in the above embodiments may be realized by analog signal processing.

[0106] In the above-described embodiments, each component may be realized by executing a software program suitable for that component, or 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.

[0107] Furthermore, each component may be realized by hardware. For example, each component may be a circuit (or integrated circuit). These circuits may form a single circuit as a whole, or each may be a separate circuit. Furthermore, each of these circuits may be a general-purpose circuit or a dedicated circuit.

[0108] Furthermore, the general or specific aspects of the present disclosure may be realized as a system, device, method, integrated circuit, computer program, or computer-readable recording medium such as a CD-ROM. Also, they may be realized as any combination of a system, device, method, integrated circuit, computer program, and recording medium. For example, the present disclosure may be implemented as a communication control method executed by a computer, or may be realized as a program for causing a computer to execute such a communication control method. Also, the present disclosure may be realized as a computer-readable non-transitory recording medium on which such a program is recorded. Note that the program here includes an application program for causing a general-purpose information terminal to function as the communication device of the above-described embodiment.

[0109] In addition, this disclosure also includes forms obtained by applying various modifications to each embodiment that a person skilled in the art would think of, or forms realized by arbitrarily combining the components and functions of each embodiment within the scope that does not deviate from the intent of this disclosure.

[0110] (Summary) As described above, the communication device 1 (e.g., second device 1B) according to the first aspect includes a communication circuit 11 that communicates with each of a first communication device (e.g., first device 1A) and a second communication device (e.g., access point 2), and a processing circuit 12 that controls the communication circuit 11. The processing circuit 12 determines whether direct communication with the first communication device is possible in a first mode (e.g., LPI mode) based on a reception result of a signal received by the communication circuit 11 from the second communication device. If the processing circuit 12 determines that direct communication with the first communication device is possible in the first mode, it controls the communication circuit 11 to communicate directly with the first communication device in the first mode. If the processing circuit 12 determines that direct communication with the first communication device is not possible in the first mode, it controls the communication circuit 11 to communicate directly with the first communication device in a second mode (e.g., VLP mode) different from the first mode.

[0111] This has the advantage that direct communication with other communication devices can be easily maintained because direct communication is continued without being temporarily interrupted by changing the operation mode.

[0112] In addition, in the communication device 1 relating to the second aspect, in the first aspect, the processing circuit 12 determines that direct communication with the first communication device in the first mode is not possible if the radio wave strength of the signal from the second communication device received by the communication circuit 11 is below a threshold.

[0113] This has the advantage that the accuracy of determining that direct communication with the first communication device in the first mode is not possible can be easily improved since the determination is made based on the radio wave strength of the signal from the second communication device.

[0114] Furthermore, a communication device 1 according to a third aspect includes a communication circuit 11 that communicates with each of a first communication device (e.g., a second device 1B) and a second communication device (e.g., an access point 2), and a processing circuit 12 that controls the communication circuit 11. The processing circuit 12 determines whether direct communication with the first communication device is possible in a first mode (e.g., an LPI mode) based on a reception result of a signal received by the communication circuit 11 from the second communication device. If the processing circuit 12 determines that direct communication with the first communication device is possible in the first mode, it controls the communication circuit 11 to transmit an instruction to the first communication device to communicate directly with the communication circuit 11 in the first mode. If the processing circuit 12 determines that direct communication with the first communication device is not possible in the first mode, it controls the communication circuit 11 to transmit an instruction to the first communication device to communicate directly with the communication circuit 11 in a second mode (e.g., a VLP mode) different from the first mode.

[0115] This has the advantage that direct communication with other communication devices can be easily maintained because direct communication is continued without being temporarily interrupted by changing the operation mode.

[0116] In addition, in the communication device 1 relating to the fourth aspect, in the third aspect, the processing circuit 12 determines that direct communication with the first communication device in the first mode is not possible if the radio wave strength of the signal from the second communication device received by the first communication device is below a threshold.

[0117] This has the advantage that the accuracy of determining that direct communication with the first communication device in the first mode is not possible can be easily improved since the determination is made based on the radio wave strength of the signal from the second communication device.

[0118] In addition, in the communication device 1 according to the fifth aspect, in any one of the first to fourth aspects, the transmission power in the second mode is lower than that in the first mode.

[0119] This has the advantage that existing systems are less susceptible to radio wave interference caused by the signal compared to when the signal is transmitted in the first mode.

[0120] In addition, in the communication device 1 according to the sixth aspect, in the fifth aspect, the second communication device is the access point 2. The first mode is the LPI mode. The second mode is the VLP mode.

[0121] This has the advantage that it is easy to maintain direct communication between the communication device 1 and the first communication device while complying with the conditions stipulated in the Radio Law Enforcement Regulations and the like.

[0122] In addition, in the communication device 1 relating to the seventh aspect, in any one of the first to sixth aspects, if the processing circuit 12 determines that direct communication with the first communication device is not possible in the first mode, it causes the communication device 1 and the first communication device to execute a process of determining whether the communication quality is better for direct communication or communication via the second communication device, and if it determines that the communication quality via the second communication device is good, it causes the communication device 1 and the first communication device to execute a process of communicating with the first communication device via the second communication device.

[0123] This has the advantage that communication between the communication device 1 and the first communication device can be carried out using the communication device with better communication quality, making it easier to improve the communication quality of communication between the communication device 1 and the first communication device.

[0124] In addition, in the communication device 1 relating to the eighth aspect, in any one of the first to seventh aspects, when the first communication device cannot communicate with the second communication device, the processing circuit 12 causes the communication device 1 and the first communication device to execute a process of performing parent-child communication in which one of the communication device 1 and the first communication device is the parent station and the other is the child station.

[0125] This has the advantage that even if the first communication device cannot communicate with the second communication device, communication between the communication device 1 and the first communication device can be easily maintained.

[0126] In addition, in the communication device 1 according to the ninth aspect, in any one of the first to eighth aspects, the processing circuit 12 controls the communication circuit 11 to perform both communication with each of the first communication device and the second communication device in a first frequency band (e.g., the 6 GHz band) using the first mode and the second mode, and communication with each of the first communication device and the second communication device in a second frequency band (e.g., the 5 GHz band or the 2.4 GHz band) different from the first frequency band.

[0127] This has the advantage that even if communication between the communication device 1 and the first communication device cannot be performed in the first frequency band, communication between the communication device 1 and the first communication device can be performed in the second frequency band, making it easier to maintain communication between the communication device 1 and the first communication device.

[0128] In addition, in the communication device 1 relating to the 10th aspect, in any one of the first to ninth aspects, when the processing circuit 12 determines that the radio wave strength of a signal from a second communication device received by either the communication device 1 or the first communication device is within a predetermined range, information indicating that the radio wave strength is weak is output to the outside from either the communication device 1 or the first communication device.

[0129] In addition, in the communication device 1 according to an eleventh aspect, in any one of the first to tenth aspects, the processing circuit 12 further determines whether or not either the communication device 1 or the first communication device is outdoors. If the processing circuit 12 determines that either the communication device 1 or the first communication device is outdoors, the processing circuit 12 controls the communication circuit 11 to communicate directly with the first communication device in a second mode different from the first mode.

[0130] This has the advantage that, for example, when there is a condition in the Radio Law Enforcement Regulations that prohibits direct communication between communication device 1 and the first communication device outdoors, it is easier to maintain direct communication between communication device 1 and the first communication device while complying with that condition.

[0131] In addition, in a communication control method according to a twelfth aspect, communication is performed with each of a first communication device (e.g., first device 1A) and a second communication device (e.g., access point 2) using a communication circuit 11. In the communication control method, based on a reception result of a signal received by the communication circuit 11 from the second communication device, it is determined whether direct communication with the first communication device is possible in a first mode (e.g., LPI mode). In the communication control method, if it is determined that direct communication with the first communication device is possible in the first mode, the communication circuit 11 is controlled to communicate directly with the first communication device in the first mode. In the communication control method, if it is determined that direct communication with the first communication device is not possible in the first mode, the communication circuit 11 is controlled to communicate directly with the first communication device in a second mode (e.g., VLP mode) different from the first mode.

[0132] This has the advantage that direct communication with other communication devices can be easily maintained because direct communication is continued without being temporarily interrupted by changing the operation mode.

[0133] In addition, in a communication control method according to a thirteenth aspect, communication is performed between a first communication device (e.g., second device 1B) and a second communication device (e.g., access point 2) using communication circuit 11. In the communication control method, based on a reception result of a signal received by communication circuit 11 from the second communication device, it is determined whether direct communication with the first communication device is possible in a first mode (e.g., LPI mode). In the communication control method, if it is determined that direct communication with the first communication device is possible in the first mode, communication circuit 11 is controlled to transmit to the first communication device an instruction to communicate directly with communication device 1 in the first mode. In the communication control method, if it is determined that direct communication with the first communication device is not possible in the first mode, communication circuit 11 is controlled to transmit to the first communication device an instruction to communicate directly with communication device 1 in a second mode (e.g., VLP mode) different from the first mode.

[0134] This has the advantage that direct communication with other communication devices can be easily maintained because direct communication is continued without being temporarily interrupted by changing the operation mode.

[0135] A program according to a fourteenth aspect causes one or more processors to execute the communication control method of the twelfth or thirteenth aspect.

[0136] This has the advantage that direct communication with other communication devices can be easily maintained because direct communication is continued without being temporarily interrupted by changing the operation mode.

[0137] The communication device and the like of the present disclosure can be applied to devices and the like that communicate using radio waves.

[0138] REFERENCE SIGNS LIST 1 Communication device 11 Communication circuit 111 Antenna 112 RF-SW 113 Receiving circuit 114 Transmitting circuit 115 RF power control circuit 12 Processing circuit 13 Memory 1A First device (first communication device) 1B Second device 2 Access point (second communication device) 101 First slave station 102 Second slave station 103 Master station A1 Specified range A2 Communicable range

Claims

1. A communication device comprising: a communication circuit that communicates with each of a first communication device and a second communication device; and a processing circuit that controls the communication circuit, wherein the processing circuit determines whether direct communication with the first communication device is possible in a first mode based on a reception result of a signal received by the communication circuit from the second communication device; if it is determined that the direct communication with the first communication device is possible in the first mode, it controls the communication circuit to perform the direct communication with the first communication device in the first mode; and if it is determined that the direct communication with the first communication device is not possible in the first mode, it controls the communication circuit to perform the direct communication with the first communication device in a second mode different from the first mode.

2. The communication device according to claim 1, wherein the processing circuit determines that the direct communication with the first communication device in the first mode is not possible when the radio wave strength of the signal received by the communication circuit from the second communication device is below a threshold value.

3. A communication device comprising: a communication circuit that communicates with each of a first communication device and a second communication device; and a processing circuit that controls the communication circuit, wherein the processing circuit determines whether direct communication with the first communication device in a first mode is possible based on a reception result of a signal received by the communication circuit from the second communication device; if it is determined that the direct communication with the first communication device in the first mode is possible, controls the communication circuit to send to the first communication device an instruction to perform the direct communication with the communication circuit in the first mode; and if it is determined that the direct communication with the first communication device in the first mode is not possible, controls the communication circuit to send to the first communication device an instruction to perform the direct communication with the communication circuit in a second mode different from the first mode.

4. The communication device according to claim 3, wherein the processing circuit determines that the direct communication with the first communication device in the first mode is not possible when the radio wave strength of the signal received by the first communication device from the second communication device is below a threshold value.

5. The communication device according to any one of claims 1 to 4, wherein the second mode has a lower transmission power than the first mode.

6. The communication device according to claim 5, wherein the second communication device is an access point, the first mode is a Low Power Indoor (LPI) mode, and the second mode is a Very Low Power (VLP) mode.

7. The communication device according to claim 1 or 2, wherein the processing circuit causes the communication device and the first communication device to execute the following process: if it determines that direct communication with the first communication device in the first mode is not possible, determine whether the communication quality is better between the direct communication or communication via the second communication device; and if it determines that the communication quality via the second communication device is good, execute a process to communicate with the first communication device via the second communication device.

8. A communication device according to claim 1 or 2, wherein the processing circuit, when the first communication device cannot communicate with the second communication device, causes the communication device and the first communication device to execute a process for parent-child communication in which one of the communication device and the first communication device is a parent station and the other is a child station.

9. A communication device according to claim 1 or 2, wherein the processing circuit controls the communication circuit to perform both communication with each of the first communication device and the second communication device in a first frequency band using the first mode and the second mode, and communication with each of the first communication device and the second communication device in a second frequency band different from the first frequency band.

10. A communication device as described in claim 1 or 2, wherein, when the processing circuit determines that the radio wave strength of a signal from the second communication device received by either the communication device or the first communication device is within a predetermined range, it causes either the communication device or the first communication device to output information indicating that the radio wave strength is weak to the outside.

11. A communication device as described in claim 1 or 2, wherein the processing circuit further determines whether either the communication device or the first communication device is located outdoors, and if it determines that either the communication device or the first communication device is located outdoors, controls the communication circuit to perform the direct communication with the first communication device in a second mode different from the first mode.

12. A communication control method comprising: communicating with each of a first communication device and a second communication device using a communication circuit; determining whether direct communication with the first communication device in a first mode is possible based on a reception result of a signal received by the communication circuit from the second communication device; controlling the communication circuit to perform the direct communication with the first communication device in the first mode if it is determined that the direct communication with the first communication device is possible in the first mode; and controlling the communication circuit to perform the direct communication with the first communication device in a second mode different from the first mode if it is determined that the direct communication with the first communication device is not possible in the first mode.

13. A communication control method comprising: communicating with a first communication device and a second communication device using a communication circuit; determining whether direct communication with the first communication device in a first mode is possible based on a reception result of a signal received by the communication circuit from the second communication device; controlling the communication circuit to send an instruction to the first communication device to perform the direct communication with the communication circuit in the first mode if it is determined that the direct communication with the first communication device in the first mode is possible; and controlling the communication circuit to send an instruction to the first communication device to perform the direct communication with the communication circuit in a second mode different from the first mode if it is determined that the direct communication with the first communication device in the first mode is not possible.

14. A program causing one or more processors to execute the communication control method according to claim 12 or 13.

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