JP2013118693A - Communication device, control method thereof and computer program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that it is necessary to check whether data communication via a relay device is enabled by transmitting a packet for inspection, and it is bothersome to check in order to search for an alternative relay device when a condition of direct communication is deteriorated.SOLUTION: On the basis of beacon information, received during communication, which is transmitted from the other device, a communication device selects a device which is receiving a signal of a destination device and where a relay function is enabled as a relay device.

Description

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

  In a wireless network using a wireless transmission technology standardized by IEEE 802.11, there are a route for communicating directly between terminal devices and a route for communicating via a base station such as an access point.

  Patent Document 1 discloses the following method as the route selection method. That is, transmission path information is obtained and updated by periodically transmitting and receiving frames to both communication paths, and based on this, it is determined whether to select a transmission path of direct transmission or indirect transmission.

JP 2006-166313 A

  In the above proposal, when the first transmission path and the second transmission path are known, that is, when the relay apparatus is known in advance, the transmission path is selected. However, when the relay device necessary for the second transmission path is not yet determined, it is necessary to start from the search for the relay device, but nothing is said about the method for searching for the relay device.

  In addition, it is necessary to periodically transmit dummy data that is not necessary in order to select direct communication or communication via a relay device, which complicates the selection procedure and selects a relay device. However, there is a problem that radio resources are consumed wastefully.

  Accordingly, an object of the present invention is to provide a technique for efficiently searching for a relay device without wasting radio resources.

  In view of the above problems, the present invention searches and selects a relay device by a simple method of using a normally received notification signal in preparation for a case where a transmission path state during direct communication deteriorates. If the transmission path condition deteriorates, communication is maintained by switching to the selected relay device.

  Specifically, the present invention is a communication device capable of direct wireless communication with another communication device and wireless communication via a relay device, and receiving a notification signal from the relay device Wireless communication between the communication device and the other communication device based on whether the notification signal includes means and an address of the other communication device with which the communication device is directly performing wireless communication. The determination means for determining whether or not the relay device is capable of relaying, and the relay for which the wireless communication is determined to be relayable by the determination means on the route of direct wireless communication with the other communication device It is characterized by switching to a route through a device and communicating.

  According to the present invention, it is possible to efficiently search for a relay device without wasting radio resources, and to perform communication using the searched relay device.

It is an example of the connection block diagram of the radio | wireless communications system 100 in the 1st Embodiment of this invention. It is an example of the internal structure of the radio | wireless communication device 200 in embodiment of this invention. It is an example of the internal structure of the relay device 103 in embodiment of this invention. It is a figure explaining the frame format of BPOIE500. It is a figure explaining the frame format of bridge IE550. It is a flowchart which shows an example of the operation | movement in the 1st Embodiment of this invention. It is a flowchart which shows an example of the operation | movement in the 2nd Embodiment of this invention. It is an example of the connection block diagram of the radio | wireless communications system 800 in the 2nd Embodiment of this invention. It is a figure which shows an example of a structure of the relay device list | wrist in the 2nd Embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

<First Embodiment>
In the present embodiment, when the transmitting device 101, the receiving device 102, and the relay device 103 exist in the same wireless network, communication via the relay device is interrupted when direct communication from the transmitting device to the receiving device is interrupted. Switch to.

  FIG. 1 shows an example of a connection configuration diagram of a wireless communication system 100 in the present embodiment. The transmission device 101, the reception device 102, and the relay device 103 constitute the same wireless network capable of IP protocol communication according to the wireless transmission technology of IEEE 802.11, and the relay device 103 has a relay function between other devices. In the present embodiment, the same wireless network is used for explanation, but the present invention can be applied to any wireless network in which each device can communicate broadcast signals with each other. The transmission path 104 is a path used when the transmitting device 101 and the receiving device 102 communicate directly. The transmission path 105 is used when the reception device 102 and the relay device 103 communicate with each other, and the transmission path 106 is used when the transmission device 101 and the relay device 103 communicate with each other. When the relay device 103 operates as a relay device for communication between the transmission device 101 and the reception device 102, the transmission path 105 and the transmission path 106 are used instead of the transmission path 104.

  FIG. 2 shows an example of the internal configuration of the wireless communication device 200. Both the transmission device 101 and the reception device 102 are wireless communication devices 200. The CPU 201 performs control of the entire device and data transmission / reception according to a program on the memory 202. The memory 202 stores a device control program and transmission / reception data. Further, the memory 202 also holds the state of the relay device as described in the second embodiment. The modem 203 has a baseband and RF (Radio Frequency), and performs modulation / demodulation and conversion into a radio signal. The antenna 204 radiates and receives RF signals into space.

  A MAC (Medium Access Control) 205 is media access control, and performs medium control including frame creation such as a beacon signal in a wireless section. The receiving device notification unit 206 extracts the address of the transmission source device of the notification signal from the notification signal received by the MAC 205. The extracted address is included in the notification signal and transmitted. For example, in FIG. 1, it is assumed that the receiving device 102 has received a notification signal from the relay device 103. At this time, the reception device notification unit 206 in the reception device 102 extracts the address of the relay device 103 from the received notification signal and transmits a notification signal including the address. Therefore, the transmission device 101 that has received the notification signal from the reception device 102 can communicate with the relay device 103 and the reception device 102 by confirming that the notification signal includes the address of the relay device 103. It turns out. In this way, the wireless communication device can notify the relay device 103 that it is a device capable of wireless communication. In the present embodiment, a beacon is treated as an example of a notification signal below, but it goes without saying that the present invention can be applied not only to a beacon as long as each device communicates with each other periodically.

  An LLC (Logical Link Control) 207 performs logical link control. The device verification unit 208 acquires a list of devices that transmitted beacons to the beacon transmission source device from an information element (IE) included in the received beacon, and includes the address of the target device. Collate. Note that the device verification unit 208 holds in advance the address of the target device for the verification. Here, the information element is an information element constituting a beacon.

  The target device in this embodiment is the receiving device 102 for the transmitting device 101 and the transmitting device 101 for the receiving device 102. The relay device search unit 209 searches for a device having a relay function using an information element included in the beacon received by the antenna 204. The relay request unit 210 transmits a relay request message to the relay device 103. By transmitting the relay request message, the relay device 103 requests the transmission device 101 to transmit the data transmitted to the relay device 103 via the transmission path 106 to the reception device 102 via the transmission path 105. When the relay device 103 responds to the relay request message with respect to the relay request message, the transmission path switching unit 211 changes the communication from direct communication to communication via the relay device 103.

  FIG. 3 shows an example of the internal configuration of the relay device 103. Portions that are substantially the same as those of the wireless communication device 200 are assigned the same reference numerals, and descriptions thereof are omitted. The relay function notification unit 302 included in the LLC 301 adds a bridge IE 550 indicating that the relay function notification unit 302 has a relay function to the beacon transmitted by the relay device 103 and performs broadcast transmission. The bridge IE 550 will be described later.

  After confirming the transmission source device of the signal received by the MAC 205, the relay function unit 303 determines whether the signal is a relay request message. If the received signal is a relay request message, if it can relay, the relay permission message is transmitted to the transmission source device, and the operation of relaying data from the transmission source device to the designated device is started. For example, when a relay request message from the transmission device 101 to the reception device 102 is received, the relay function unit 303 in the relay device 103 temporarily stores the data received from the transmission device 101 in the memory 202 and transmits the data to the reception device 102.

  FIG. 4 is an example of a configuration of a super frame 400 with which each device communicates in the present embodiment. The superframe 400 includes a beacon period 401, a contention access time, and a channel time allocation period. The description is omitted except for the beacon period 401. Using the beacon period 401, each device transmits a beacon directed to another device.

  The beacon period 401 is divided into a plurality of beacon slots (BS) 402. Each device transmits its beacon at a time corresponding to any one beacon slot 402 assigned. Description of the method for assigning the beacon slot 402 is omitted.

  A beacon transmitted during the beacon slot 402 includes a plurality of information elements (IEs) 403. What information elements 403 are included depends on the type and situation of the device. Examples of the information element 403 include the BPOIE 500 and the bridge IE 550 shown in FIG.

  FIG. 5A shows a frame format of a BPOIE (Beacon Period Occupancy Information Element) 500 that is an information element of a beacon transmitted by the reception device notification unit 206 in each MAC 205 of the transmission device 101, the reception device 102, and the relay device 103. Show. All beacons include BPOIE 500 as an information element. In general, BPOIE is used to secure a beacon period, which is a slot in which each device transmits a beacon. In this description, BPOIE is used to search for a relay device.

  Element ID 501 is an identifier uniquely assigned to each information element of the beacon. When the information element is BPOIE500, an identifier indicating that it is BPOIE500 is included in Element ID501. This Element ID 501 makes it possible to extract the BPOIE 500 from the beacon. Length 502 indicates the length of the BPOIE 500. BP (Beacon Period) Length 503 indicates the length of a period during which a beacon is transmitted. The Beacon Slot Info Bitmap 504 indicates the usage status of each slot that can be used for beacon transmission. DevAddr 505 indicates the source address of the beacon received by the device. Since DevAddr 505 handles the transmission source of the received beacon, it does not include its own address.

  FIG. 5B shows a frame format of the bridge IE 550 that is an information element of a beacon broadcasted by the relay function notification unit 302 in the relay device 103. Bridge IE 550 is included only in the beacon transmitted by relay device 103 and is not included in the beacon transmitted by wireless communication device 200. Further, by analyzing the bridge IE 550, it is possible to determine whether or not the relay device 103 is in a relayable state.

  Element ID 551 is an identifier uniquely assigned to each information element of the beacon. When the information element is the bridge IE 550, an identifier indicating that the information element is the bridge IE 550 is included in the element ID 551. The element ID 551 of the bridge IE 550 is different from the element ID 501 of the BPOIE 500. By determining whether or not the bridge IE 550 is included in the received beacon, it is possible to determine whether or not the transmission source device is the relay device 103. Length 552 indicates the length of the bridge IE 550. Bridge 553 indicates the presence or absence of a relay function. A MAS (Medium Access Slot) 554 indicates the number of empty slots that the relay device can use as a relay function. When this value is 0, it indicates that there is no bandwidth that can be used and therefore relaying is not possible.

  Next, an operation example of relay device selection will be described with reference to FIG.

  FIG. 6 is a flowchart illustrating an example of an operation of selecting a relay device in the transmission device 101 and the reception device 102. The processing in this flowchart is performed by the CPU 201 executing a program on the memory 202. Although the operation in the transmission device 101 will be described here, the operation in the reception device 102 is the same. It is assumed that the state before the start of the flowchart is that the transmitting device 101 is communicating with the receiving device 102 or is about to communicate.

  In step S601, it is determined whether the other party address is included in the received beacon. First, the transmitting device 101 demodulates the signal received by the antenna 204 by the modem 203 and analyzes the header of the received data by the MAC 205. When it is determined from the header information that the received signal is a beacon, the receiving device notification unit 206 extracts the BPOIE 500 from this beacon. Subsequently, the device verification unit 208 in the LLC 207 determines whether or not the DevAddr 505 included in the BPOIE 500 includes the address of the receiving device 102 that is the target device.

  If the address of the receiving device 102 is included (“Yes” in step S601), it means that the relay device 103 can communicate with the receiving device 102. As a matter of course, since the transmission device 101 receives the beacon from the relay device 103, the relay device 103 and the transmission device 101 can communicate with each other. Therefore, if the relay device 103 has a relay function and can relay, the transmission device 101 and the reception device 102 can communicate with each other via the relay device 103. Therefore, the process proceeds to step S602 where it is determined whether the relay device 103 has a relay function.

  When the DevAddr 505 of the receiving device 102 is not included (“No” in step S601), it means that the relay device 103 cannot communicate with the receiving device 102. Therefore, the transmission device 101 cannot communicate with the reception device 102 via the relay device 103. Therefore, the transmitting device 101 continues to directly communicate with the receiving device 102 and returns to step S601. If a failure occurs in the transmission path 104 at this stage, communication cannot be performed via the relay device 103, and the transmission device 101 and the reception device 102 cannot communicate with each other.

  In step S602, the relay device search unit 209 in the LLC 207 determines whether or not the bridge IE 550 is included in the received beacon.

  When the bridge IE 550 is included and the value of Bridge 553 is 1 (“Yes” in step S602), it means that the relay device 103 has a relay function. In this case, the transmitting device 101 proceeds to step S603 in order to determine the communication status with the receiving device 102.

  When the bridge IE 550 is not included in the beacon, or is included but the value of Bridge 553 is 0 (“No” in step S602), it means that the relay device 103 does not have a relay function. Therefore, the transmission device 101 cannot communicate with the reception device 102 via the relay device 103. Therefore, the transmitting device 101 continues to directly communicate with the receiving device 102 and returns to step S601.

  In step S603, the transmission device 101 determines whether communication with the reception device 102 is possible. This determination can be made by the transmission device 101 receiving a beacon from the reception device 102, but can also be made by receiving data other than a beacon.

  If communication is possible (“Yes” in step S603), there is no need to switch from the current direct communication to the communication via the relay device 103, and the process returns to step S601.

  If communication is not possible (“No” in step S603), the current direct communication cannot be continued, and the process proceeds to step S604 to switch to communication via the relay device 103.

  In step S <b> 604, the relay request unit 210 in the transmission device 101 generates a relay request message addressed to the relay device 103 and transmits the relay request message from the antenna 204 to the relay device 103 via the modem 203.

  In step S605, the transmission device 101 determines whether a relay permission message from the relay device 103 has been received.

  If the relay permission message cannot be received from the relay device 103 within the predetermined time (“No” in step S605), the process returns to step S604 and transmits the relay request message again. If the relay request is made a predetermined number of times in step S604, it is determined that relaying is impossible and the flowchart is ended. In this case, since communication cannot be performed via the relay device 103, the transmission device 101 and the reception device 102 cannot communicate.

  When the relay permission message is received (“Yes” in step S605), the transmission path switching unit 211 in the transmission device 101 switches communication with the reception device 102 directly from the relay device 103. As a result, the transmission device 101 can communicate with the reception device 102 via the relay device 103.

  In the above description, it has been confirmed that the address of the receiving device 102 is included in the beacon transmitted by the relay device 103 in step S601. However, the transmission device 101 may determine that the relay device 103 and the reception device 102 can communicate with each other by confirming that the address of the relay device 103 is included in the beacon transmitted by the reception device 102.

  As described above, it is possible to easily determine whether or not communication that relays the beacon transmission source device is possible only by determining the presence or absence of the relay function and the presence or absence of the address of the communication partner included in the received beacon information element.

<Second Embodiment>
In the present embodiment, a mode in which the present invention is applied when a plurality of relay devices exist in the same wireless network will be described.

  FIG. 8 shows an example of a connection configuration diagram of the wireless communication system 800 in the present embodiment. A transmitting device 801, a receiving device 802, and three relay devices 803 to 805 exist. The transmitting device 801 can receive the beacons of the receiving device 802, the relay device A 803, the relay device B 804, and the relay device C 805. The receiving device 802 can receive the beacons of the transmitting device 801, the relay device A 803, and the relay device B 804, but cannot receive the beacon of the relay device C 805. The relay device A 803 can receive the beacon of the transmission device 801, the reception device 802, and the relay device B 804, but cannot receive the beacon of the relay device C 805. The relay device B 804 can receive the beacons of the transmission device 801, the reception device 802, the relay device A 803, and the relay device C 805. The relay device C805 can receive the beacons of the transmission device 801 and the relay device B804, and cannot receive the beacons of the reception device 802 and the relay device A803.

  The relay device C805, the relay device A803, and the relay device B804 are set in the descending order of available MAS that can be used as the relay function.

  The internal configurations of the transmission device 801, the reception device 802, and the relay devices 803 to 805 are the same as those in the first embodiment, and a description thereof will be omitted.

  An operation example of relay device selection will be described with reference to FIG.

  FIG. 7 is a flowchart showing an example of the relay device selection operation in the transmission device 801 and the reception device 802. The processing in this flowchart is performed by the CPU 201 executing a program on the memory 202. Here, the operation in the transmitting device 801 will be described, but the operation in the receiving device 102 is the same. Since the transmitting device 801 can receive beacons from all the devices 802 to 805, the transmitting device 801 receives the beacons from all the devices during one frame period. Although the case where beacons are received in the order in which the present embodiment can be best understood will be described below, it goes without saying that the present invention can be applied even in other orders. It is assumed that the state before the start of the flowchart is that the transmitting device 101 is communicating with the receiving device 102 or is about to communicate.

  In step S701, it is determined whether the other party address is included in the received beacon. First, it is assumed that the transmitting device 801 receives a beacon from the receiving device 802. In the MAC 205 in the transmission device 801, the reception device notification unit 206 extracts the BPOIE from the received beacon. Subsequently, the device verification unit in the LLC 207 detects that the addresses of the transmission device 801, the relay device A 803, and the relay device B 804 are included in the BPOIE DevAddr 505. Since the beacon received this time is transmitted by the receiving device 802, the address of the receiving device 802 is not included ("No" in step S701). Therefore, the process returns to step S701.

  In step S701 again, it is assumed that the beacon of relay device A 803 is received this time. Similarly to the above, it is detected that DevAddr 505 includes the addresses of transmission device 801, reception device 802, and relay device B 804. This time, the address of the receiving device 802 is included (“Yes” in step S701).

  In step S702, it is determined that the relay device search unit 209 includes the bridge IE 550 and that Bridge 553 is 1 (“Yes” in step S702).

  In that case, a relay device list including the usable MAS value indicated by the MAS 554 and the relay device A 803 address is created in step S 703 and held in the memory 202.

  In step S704, it is determined whether the transmitting device 801 has processed all the beacons included in one superframe 400. Since all the beacons are not processed here (“Yes” in step S704), the process returns to step S701.

  In step S701, it is assumed that the beacon of the relay device B 804 is received this time. The processing similar to the above is performed, and in step S703, the transmission device 101 adds the relay device B 804 address and the usable MAS value to the relay device list, and stores them in the memory 202. Since all the beacons are not processed in step S704 (“Yes” in step S704), the process returns to step S701.

  Assume that the beacon of the relay device C805 is received next in step S701. This time, since the relay device C805 and the receiving device 802 cannot communicate, the DEVADDR 505 does not include the address of the receiving device 802 (“No” in step S701). Therefore, the process returns to step S701. Thus, one beacon for 400 minutes is received (“YES” in step S704). As described above, the latest communication status between each relay device 803 to 805 and the receiving device 802 and the latest usable MAS value of each relay device 803 to 805 are held in the memory 202 of the transmission device 801.

  An example of the configuration of the relay device list at this time is shown in FIG. FIG. 9 is a diagram illustrating an example of the relay device list 900. In FIG. 9, the relay device list 900 registers information of the relay device 901, the communication status 902, and the MAS 903, respectively. A (803), B (804), and C (805) are registered in the relay device 901, respectively. Information about each relay device A to C is registered in the communication status 902 and the MAS 903, respectively. In this embodiment, since the relay devices A (803) and B (804) can receive with the receiving device 802, the communication status 902 is registered with a value reflecting the status. In the MAS 903, the value of the number of empty slots that can be used as a relay function by each relay device is registered. In the example shown in FIG. 9, the number of MASs of the relay device C (804) is the maximum value.

  In step S705, the transmission device 801 cannot communicate with the reception device 802 (“No” in step S705). In this case, since the transmission device 801 switches to communication via the relay device, the process proceeds to step S706.

  In step S706, the relay request unit 210 in the transmission device 801 releases the MAS used for communication with the reception device 802.

  In step S707, the relay device with the largest free MAS is selected from the relay device list stored in the memory 202. In this example, the relay device A 803 is selected. In step S708, the transmitting device 801 transmits a data relay request message to the receiving device 802 to the relay device A 803.

  In step S709, the transmission device 101 determines whether a relay permission message from the relay device A 803 has been received.

  When the relay permission message response is received (“Yes” in step S709), in step S711, the transmission path switching unit 211 in the transmission device 801 switches communication with the reception device 802 directly from the relay device A803. As a result, the transmission device 801 can communicate with the reception device 802 via the relay device A 803.

  If the relay permission message has not been received within the predetermined time (“No” in step S709), in step S710, the relay device with the next largest free MAS is selected from the relay device list stored in the memory 202, and the process proceeds to step S708. Return. In this example, the relay device B 804 is selected.

  In step S708, the transmission device 801 transmits a relay request message for data addressed to the reception device 802 to the relay device B 804. When the relay permission message response is received (“Yes” in step S709), the transmission path switching unit 211 in the transmission device 801 switches communication with the reception device 802 directly from the relay device B 804. As a result, the transmission device 801 can communicate with the reception device 802 via the relay device B 804.

  If there are no more relay devices that can be selected in step S710, the process is repeated again from the beginning of the list. If the relay permission message cannot be received after repeating the predetermined number of times, it is determined that relaying is impossible and the flowchart is ended. In this case, since communication cannot be performed via any relay device, communication between the transmission device 801 and the reception device 802 becomes impossible.

  As described above, a device that can be relayed is selected from the received beacon, and a relay request is made in the order of devices with a large bandwidth that can be used for relaying from information included in the beacon, so that an appropriate relay device is always selected. It becomes possible.

<Other embodiments>
Note that the present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, and a printer), and a device (for example, a copying machine and a facsimile device) including a single device. You may apply to.

  The object of the present invention can also be achieved by supplying, to a system, a storage medium that records the code of a computer program that realizes the functions described above, and the system reads and executes the code of the computer program. In this case, the computer program code itself read from the storage medium realizes the functions of the above-described embodiments, and the storage medium storing the computer program code constitutes the present invention. In addition, the operating system (OS) running on the computer performs part or all of the actual processing based on the code instruction of the program, and the above-described functions are realized by the processing. .

Furthermore, you may implement | achieve with the following forms. That is, the computer program code read from the storage medium is written into a memory provided in a function expansion card inserted into the computer or a function expansion unit connected to the computer. Then, based on the instruction of the code of the computer program, the above-described functions are realized by the CPU or the like provided in the function expansion card or function expansion unit performing part or all of the actual processing.
When the present invention is applied to the above storage medium, the computer program code corresponding to the flowchart described above is stored in the storage medium.

101 Transmission device 102 Reception device 103 Relay device 104 Transmission path 105 Transmission path 106 Transmission path

The present onset Ming, communication apparatus and an object thereof is to allow the relay processing efficiently.

A communication apparatus according to one aspect of the present invention includes address information of a first other communication apparatus with which the communication apparatus is directly communicating, and a third other communication apparatus with which the communication apparatus is not in direct communication. Transmitting means for transmitting a signal not including the address information, and in response to a request from the third other communication apparatus based on the signal transmitted by the transmitting means, the first other communication apparatus and the third Relay means for relaying communication with other communication devices.

According to the present invention, a communication apparatus can efficiently perform relay processing .

Claims (11)

A communication device capable of direct wireless communication with another communication device and wireless communication via a relay device,
Receiving means for receiving a notification signal from the relay device;
Based on whether or not the notification signal includes an address of another communication device with which the communication device is directly performing wireless communication, the wireless communication between the communication device and the other communication device is relayed. Determining means for determining whether or not the device can relay;
A communication unit that switches a direct wireless communication route with the other communication device to a route through the relay device that is determined to be relayable by the determination unit;
A communication device comprising: Further comprising request means for requesting the relay device to relay the wireless communication when direct wireless communication with the other communication device cannot be continued.
The communication means switches a wireless communication route with the other communication device to a route through the relay device and continues wireless communication when relaying of communication by the relay device is permitted in response to the request. The communication device according to claim 1. When the communication system includes a plurality of relay devices, the communication system further comprises extraction means for extracting information on the number of available slots in each relay device from a plurality of broadcast signals received from the plurality of relay devices,
When the wireless communication with the other communication device cannot be continued, the requesting unit relays the relay device to the relay device having the largest number of empty slots among the relay devices determined to be able to relay the wireless communication. The communication device according to claim 2, wherein:   The broadcast signal is a beacon signal, and includes at least the presence / absence of a relay function in the relay device and an address of a communication device capable of wireless communication with the relay device. The communication device described in 1. When the communication device receives the notification signal from the relay device, the communication device notifies the relay device of reception of the notification signal;
The communication device according to claim 4, wherein the communication device that has made the notification is determined by a communication device capable of wireless communication with the relay device and the relay device. A communication device control method capable of direct wireless communication with another communication device and wireless communication via a relay device,
Receiving a notification signal from the relay device;
Based on whether or not the notification signal includes an address of another communication device with which the communication device is directly performing wireless communication, the wireless communication between the communication device and the other communication device is relayed. A determination step of determining whether or not the device can be relayed;
A switching step of switching a path of direct wireless communication with the other communication device to wireless communication via a relay device that is determined in the determination step that the relay device can relay the wireless communication;
A method for controlling a communication device, comprising: Further comprising a requesting step of requesting the relay device to relay wireless communication with the other communication device when direct wireless communication with the other communication device cannot be continued.
7. The switching step according to claim 6, wherein when the relay is permitted by the relay device, a path of wireless communication with the other communication device is switched to a path via the relay device. 8. A method for controlling a communication device. An extraction step of extracting information on the number of available slots in each relay device from a plurality of broadcast signals received from a plurality of relay devices;
In the requesting step, when wireless communication with the other communication device cannot be continued, the relay device selected based on the number of empty slots among the relay devices determined to be able to relay the wireless communication. The communication device control method according to claim 7, wherein the relay is requested.   9. The broadcast signal according to claim 6, wherein the notification signal is a beacon signal and includes at least the presence / absence of a relay function in the relay device and an address of a communication device capable of wireless communication with the relay device. A communication device control method according to claim 1. A notification step of notifying the relay device of reception of the notification signal when the notification signal is received from the relay device;
The communication device control method according to claim 9, wherein the communication device that has made the notification is determined by a communication device capable of wireless communication with the relay device and the relay device.   A computer program for causing a computer to function as the communication device according to any one of claims 1 to 5.