JP4612828B2 - COMMUNICATION DEVICE, COMMUNICATION METHOD, AND COMPUTER PROGRAM - Google Patents

Description

  The present invention relates to a communication apparatus, a communication method, and a computer program, and is particularly suitable for communication between communication apparatuses according to device information.

  One of the methods for the peripheral device to notify its own status is a standard (Universal Plug and Play, hereinafter referred to as UPnP) defined by the Universal Plug and Play Forum (see Patent Document 1). By using UPnP, which is an upper layer protocol, it is possible to execute a function for performing device detection and information notification of the detected device (so-called discovery function). Here, a device that detects a device is called a control point, and a device that is searched for is called a device.

FIG. 9 shows a conventional operation procedure when notifying device information.
In FIG. 9, when a device joins the network, the device itself uses the multicast packet to indicate the location (service type, identification number, valid time of this information (cache control), etc., in which UPnP information is written, as an Advertise signal. Control point) (step S901).

When the effective time approaches after notifying such information, the device notifies the network (control point) of the same information as described above as a refresh signal using a multicast packet (step S902). Thereafter, the device notifies the Refresh signal every time it reaches the valid time (steps S903 and S904).
The device notifies the network (control point) of information indicating that to the network (control point) using a multicast packet as a Cancel signal before the power is shut off or before leaving the network (step S905). .

  Here, for example, when a device participating in the network enters the sleep mode, conventionally, a cancel command (Cancel signal) is issued from the device to the network to disconnect the upper layer, and then the lower layer connection. To disconnect the communication link between the device and the network. When the device returns from the sleep mode, first, the lower layer is connected. Then, after assigning the device IP number, information such as the device IP number, information valid time, and the location where the device information is stored is reported as an Advertise signal to the network (control point) to connect to the upper layer. And re-establishing the link between the device and the network.

JP 2003-8610 A

  However, in the background art described above, every time the mode is shifted to the sleep mode, not only the lower layer but also the upper layer is disconnected. For this reason, it has been necessary to cancel (send a Cancel signal) every time the sleep mode is entered. Further, every time the device returns from the sleep mode, IP assignment (IP number assignment) and advertisement (advertise signal transmission) must be performed. In this case, it may be necessary for about 7 to 8 seconds just to perform IP assignment, and there is a problem that it takes a long time to restart.

  In order to avoid this problem, when entering the sleep mode, it is conceivable to disconnect only the lower layer and maintain the connection for the upper layer. However, in this case, the sleep mode time may exceed the valid time of the information defined by the advertisement (Advertise signal) or the refresh (Refresh signal). When the sleep mode time exceeds the valid time, the lower layer connection is disconnected, so that the Refresh signal cannot be transmitted to the network and cannot be refreshed. When refreshing is not possible, problems such as inconsistencies in the protocol such as a search command being issued from the control point to the device, and invalid traffic may occur.

  On the other hand, if the valid time specified by advertisement (Advertise signal) or refresh (Refresh signal) is set long as 1 hour in advance, protocol inconsistency as described above, invalid traffic, etc. Will not happen. However, if the device and the control point are connected wirelessly in this way, the device may move out of the range (out of service area) that can be managed by the control point, such as when the device leaves the control point. is there. In this case, there is a problem that the detection is delayed until the refresh is performed. Conversely, if the effective time specified in advertisement (Advertise signal) or refresh (Refresh signal) is set to a short time, sleep is canceled each time before the expiration date, and after entering refresh, it enters sleep mode again. This causes a problem that the setting and release of the sleep must be performed frequently.

  Further, like the Direct Link Protocol (hereinafter referred to as DLP) defined by IEEE802.11e, each terminal is set to a direct communication mode in which communication is performed directly between terminals (stations) without going through an access point. When a transition is made, a terminal that has transitioned to the direct communication mode uses an unconventional channel or increases QoS (Quality of Service) traffic, etc., and searches for information such as discovery information performed by other terminals. Problems such as leaks and inability to update information occur.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to appropriately set the valid time of device information of a communication apparatus.

This onset Akira communication device, for the other communication device on the network, a communication apparatus that notifies the device information including the expiration date information and the information related to the own device, according to participation in the network A first notification means for notifying device information, and whether the device information is notified by the first notification means, and whether to shift to a power saving mode for reducing power consumption in a communication unit of the communication apparatus . a first determination means for determining whether, when it is determined that the process proceeds to the power saving mode by said first determining means, the expiration date included in the device information, notified by the first notification means and second notification means for notifying the device information has been changed to a long expiration than the effective date included in the device information, in conjunction with the long term of validity of the changed releases the power saving mode And having a third notifying means for re-notification device information.
Another feature of the present invention is that a first communication mode in which communication is performed between a plurality of communication devices via an access point and direct communication between the plurality of communication devices without passing through the access point. of the second communication mode for performing communication, a communication apparatus for communicating with one of the communication mode, to other communication devices on the network, the expiration date information and the information about the own device wherein the first notifying means and, a first determination means for determining whether to shift from the first communication mode to the second communication mode, the first determination means for notifying the device information including When it is judged that the shift to the second communication mode, an expiration date to be included in the device information, a longer expiration than the effective date included in the device information when operating in the first communication mode, Said second communication And second notification means for notifying device information for changing the expiration date corresponding to the time to operate at over de,
It is characterized by having.

Communication method of the present invention, the discovery function A communication method for a communication apparatus that notifies the device information including the expiration date information and the information related to the own device, the notifying device information for the other communication devices a first notification step, after the notification of the device information in the first notification step, a determining step of determining whether to shift to the power saving mode for reducing power consumption in the communication unit of the communication device it is determined that the shift to the power saving mode by the determining step, change the expiration date included in the device information, the first notification longer expiration than the effective date included in the notification device information in step and a second notification step of notifying the device information, and releases the power saving mode in conjunction with the long expiration after the change, device A third notification step of re-notification of scan information, and having a.
Another feature of the present invention is that a first communication mode in which communication is performed between a plurality of communication devices via an access point and direct communication between the plurality of communication devices without passing through the access point. A communication method of a communication device that performs communication in any one of the second communication modes in which communication is performed, wherein information about the own device and an expiration date of the information are transmitted to another communication device. A first notification step of notifying the device information to be included; a determination step of determining whether or not to shift from the first communication mode to the second communication mode; and the determination step to enter the second communication mode. If it is determined to shift, the expiration date included in the device information is an expiration date longer than the expiration date included in the device information during operation in the first communication mode, and the second communication mode A second notification step of notifying the device information for changing the expiration date corresponding to the time to operate, and having a.

A computer program according to the present invention causes a computer to execute each step of the communication method .

According to the present invention, when changing to the power saving mode, the expiration date of the device information notified to the other communication apparatus is changed to a longer time, so the time longer than the expiration date set at the time of joining the network Can operate in power saving mode. Furthermore, since the re-notification device information cancels the power saving mode in conjunction with the expiration of the changed due to the transition to the power saving mode, the other communication device an expired device information managed Can be deterred.
Further, according to the present invention, when shifting from the first communication mode to the second communication mode, the expiration date of the device information notified to the other communication apparatus is determined according to the operation time of the second communication mode. Since the expiration date is changed, it is possible to prevent a discovery search from being leaked from another device that is not communicating in the second communication mode.

(First embodiment)
Next, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating an example of a configuration of a wireless communication network system in the present embodiment. As shown in FIG. 1, a wireless communication network system according to this embodiment includes a camera 101 having a function as a device in UPnP and a PC (personal computer) 102 having a function as a control point in UPnP. Are connected to each other.
FIG. 2 is a block diagram illustrating an example of the configuration of the camera 101. In FIG. 2, the camera 101 includes a host CPU 201, a memory 202, an imaging unit 203, an operation unit 204, and a wireless unit 205.

  The host CPU 201 controls the entire camera 101 and also performs power supply control when shifting to a power saving mode or the like. The memory 202 stores various information by storing a program executed by the host CPU 201 or saving an image photographed by the imaging unit 203. In addition, the memory 202 also functions as a work memory when the host CPU 201 executes a program. Further, connection destination information (for example, the MAC address of the PC 102) used in the wireless unit 205 is also stored in the memory 202 in advance.

  The imaging unit 203 is for imaging a subject, and includes a lens, a CCD, and the like. The operation unit 204 includes a power button, a shutter, a user interface, and the like. The wireless unit 205 has a wireless transmission / reception function compliant with, for example, IEEE 802.11, includes a Media Access Control (MAC) layer that performs medium control, and has a power-saving mode according to the communication status unique to the wireless unit.

FIG. 3 is a flowchart for explaining an example of the discovery operation according to the camera sleep mode performed in the camera 101 of the present embodiment having the above-described configuration.
In FIG. 3, first, when a power button provided on the operation unit 204 of the camera 101 is pressed by the user, the host CPU 201 executes a power-on process according to a program stored in the memory 202.
When the power-on process is completed, the host CPU 201 monitors whether or not an instruction to transmit a photographed image is given by the user operating the operation unit 204 (step S201). When transmission is instructed, the host CPU 201 activates the wireless unit 205, and the wireless unit 205 uses the same network identifier (SSID: Service Set-IDentifier), frequency channel as the PC 102 previously stored in the memory 202 as connection destination information. And participate in the same network as the PC 102 (step S202).

In the present embodiment, the camera 101 performs AD-Hoc (ad hoc) connection with the PC 102. Therefore, the wireless unit 205 assigns an IP number (IP address) to the camera 101 itself using the Auto IP protocol (step S203). If the PC 101 has a DHCP (Dynamic Host Configuration Protocol) function, an IP number may be assigned by DHCP.
When the IP number of the camera 101 is determined, the wireless unit 205 displays the notification information (Advertise signal) including the IP number of the camera 101, the information valid time (for example, 5 minutes), the position where the camera information is stored, etc. Using the layer UPnP protocol, the Ad-Hoc network is notified by a broadcast packet (step S204). This notification information is received by the PC 102. Then, the notification information is temporarily stored as a cache in the memory of the PC 102 as the camera state during the valid time included in the notification information. Also, the PC 101 is requested to connect on the communication application, and a wireless link connection state is established with the PC 101.

  If the operation unit 204 of the camera 101 has not been operated for a certain period of time, the host CPU 201 determines whether or not to execute processing for shifting the wireless unit 205 to the sleep mode (Yes in step S205). When the operation unit 204 is not operated for a certain period of time and it is determined that the wireless unit 205 shifts to the sleep mode, a UPnP protocol refresh command (Refresh signal) is issued. At this time, the valid time included in the refresh command is set to 1 hour, for example (step S206).

  Next, the host CPU 201 sets the wireless unit 205 to the sleep state (step S207). Further, the camera 101 main body also performs a power saving operation by reducing the clock speed of the host CPU 201. (Step S208)

Then, the user's operation of the operation unit 204 is monitored (step S209). If no user operation is detected, whether or not the effective time (1 hour) included in the notification information (Advertise signal) is approaching (or the effective time). Is determined (step S210). If the effective time is not approaching (or if the effective time has not elapsed), the process returns to step S209.
When the host CPU 201 detects a sleep mode return signal by operating the operation unit 204 of the camera 101 (step S209) or as a result of the determination in step S210, the effective time is approaching (or the effective time) In the case where the time elapses), the host CPU 201 restores the clock speed as the sleep release operation (step S211). When the sleep release operation of the host CPU 201 ends, it is determined whether the operation performed by the user is an OFF operation of the power button provided on the operation unit 204 (step S212). In the case of an OFF operation, the wireless unit 205 issues a UPnP protocol cancel command (Cancel signal) to the Ad-Hoc network in order to execute a power shutdown process for turning off the power of the camera 101 main body. Then, the UPnP protocol is terminated (step S221). Thereafter, the connection on the communication application is disconnected, the wireless link is disconnected (step S222), and the power is turned off (step S223).

  If the power button is not turned OFF, the host CPU 201 transmits an activation signal to the wireless unit 205 to activate (activate) the wireless unit 205 (step S213). When the wireless unit 205 is activated, it is participating in the network of the PC 102 in an active state, and the wireless unit 205 issues a refresh command (Refresh signal) in the UPnP protocol. The valid time of the refresh command is set to 5 minutes, for example (step S214). Then, processing (for example, photographing processing, photographed image reproduction processing, image transmission processing, etc.) according to the user operation is performed (step S215), and the process returns to step S205.

  On the other hand, if the host CPU 201 determines in step S205 not to execute the process of shifting to the sleep mode, the host CPU 201 determines whether or not the effective time (for example, 5 minutes) included in the notification information (Advertise signal) is approaching. It is determined (or whether or not the effective time has elapsed) (step S216). As a result of this determination, when the effective time is not approaching (or the effective time has not elapsed), the host CPU 201 monitors the operation of the operation unit 204 by the user (step S218). When an operation by the user is detected, it is determined whether this operation is an off operation of a power button provided on the operation unit 204 (step S219). If the power button is turned off as a result of this determination, the wireless unit 205 issues a UPnP protocol cancel command (Cancel signal) to the Ad-Hoc network, and ends the UPnP protocol (step S221). ). Thereafter, the connection on the communication application is disconnected, and the wireless link is disconnected (step S222).

After disconnecting the wireless link, a power shut-off process for turning off the power of the camera 101 is executed, and the power is turned off (step S223).
If the result of determination in step S219 is that the power button is not turned off, processing according to the operation (for example, shooting processing, shot image reproduction processing, image transmission processing, etc.) is performed, and the flow returns to step S216.
If it is determined in step S216 that the effective time is approaching (for example, 5 minutes), the wireless unit 205 issues a refresh command (Refresh signal) in the UPnP protocol and sets the effective time to 5 minutes again. Update (step S217). Then, the process returns to step S205.

  As described above, in the present embodiment, when the camera 101 shifts to the sleep mode, information indicating that the valid time of the UPnP information is longer than the time before the shift to the sleep mode (for example, 5 minutes is changed to 1 hour). A refresh command including is issued (step S206). Thereafter, when the sleep mode is canceled, a refresh command including information indicating the original valid time (for example, 5 minutes) is issued, and the valid time is returned to the value before the transition to the sleep mode (step S214).

  As described above, in this embodiment, even when the lower layer in the radio link is in the sleep state, the upper layer link is maintained and the effective time of the link in the upper layer when the lower layer is in the sleep state is set to be long. As a result, it is not necessary to reassign the IP number every time the device returns from the sleep mode, and invalid traffic does not occur (because the upper layer link is maintained). Further, when the lower layer is restarted, the upper layer link is immediately updated, so that the information update frequency in the PC 102 which is the connection partner can be increased. In addition, there is an effect that it is possible to reduce the restriction due to the effective time of the upper layer and set the sleep time. Therefore, the return time from the sleep mode can be shortened, and power saving can be improved, invalid traffic can be prevented, and discovery information update frequency can be prevented from decreasing. In addition, since the device information shifts to the sleep mode after extending the valid time of the device information, the time for shifting to the sleep mode can be set longer. In addition, it is possible to shift to the sleep mode for a longer time than the valid time of the device information set when joining the network. Therefore, low power consumption can be realized. In addition, it is possible to prevent the device information from being expired due to the shift to the sleep mode.

In this embodiment, the valid time of the link in the upper layer when the lower layer is in the sleep state is 1 hour, and the valid time in other cases is 5 minutes. However, the valid time is not limited to these, The effective time may be set in any way as long as the effective time of the link in the upper layer when the lower layer is in the sleep state is longer than the effective time in other cases.
In this embodiment, the camera 101 is described as an example of the wireless device. However, the wireless device is not limited to the camera 101, and may be a mobile phone or a PDA, for example.

The PC 102 has a configuration as shown in FIG. 4, for example.
FIG. 4 is a block diagram showing an example of the configuration of a computer system arranged in the PC 102.
4, the PC 102 includes a CPU 401, a ROM 402, a RAM 403, a keyboard controller (KBC) 405 of a keyboard (KB) 404, a CRT display (CRT) 406 as a display unit, a CRT controller (CRTC) 407, and a hard disk. A disk controller (DKC) 410 of (HD) 408 and a flexible disk (FD) 409 and a network interface controller (NIC) 412 for connection to the network 411 are connected to each other via a system bus 413 so as to communicate with each other. It has a configuration.

The CPU 401 comprehensively controls each component connected to the system bus 403 by executing software stored in the ROM 402 or HD 408 or software supplied from the FD 29.
In other words, the CPU 401 reads out and executes a processing program according to a predetermined processing sequence from the ROM 402, the HD 408, or the FD 409, thereby performing control for realizing an operation described later.

The RAM 403 functions as a main memory or work area for the CPU 401.
The KBC 405 controls instruction input from the KB 404 or a pointing device (not shown).
The CRTC 407 controls display on the CRT 406.
The DKC 410 controls access to the HD 408 and the FD 409 that store a boot program, various applications, an editing file, a user file, a network management program, a predetermined processing program in the present embodiment, and the like.
The NIC 402 exchanges data bidirectionally with devices or systems on the network 411.
In this embodiment, the PC 102 is described as an example of a communication partner of a camera that is a wireless device. However, a printer that can receive and print data from the camera 101, a hard disk device that can store data from the camera 101, and the like. The apparatus may be used.
In this embodiment, the ad hoc mode network conforming to IEEE802.11 has been described. However, the present invention can also be applied to an infrastructure mode network. In this case, in step S202, the camera 101 associates with the access point and participates in the network configured by the access point (connects a wireless link). In step S222, the network is connected (wireless link is connected) by performing disassociation with the access point. Further, UPnP protocol Advertise signals, cancel and refresh commands are notified to the other party via the access point.

(Second Embodiment)
Next, a second embodiment of the present invention will be described. In the first embodiment described above, the discovery operation before and after the transition to the sleep mode has been described, but in this embodiment, the discovery operation before and after the transition to the DLP mode (Direct Link Protocol) will be described. Here, the DLP mode refers to a mode in which direct communication can be performed between wireless terminal devices even in the infrastructure mode. In the following description, detailed description of the same parts as those of the first embodiment described above will be omitted.

  FIG. 5 is a diagram illustrating an example of the configuration of the wireless communication network system in the present embodiment. In FIG. 5, an access point 301 forms an infrastructure network defined by IEEE802.11. As shown in FIG. 5A, the first to third stations (STA1 to STA3) 302 to 304 within the communication range of the access point 301 have functions as wireless devices, and each access point 301 and wirelessly connected to each other. For this reason, for example, the communication between the first station 302 and the second station 303 is relayed by the access point 301.

FIG. 5B shows a configuration when the first station 302 and the second station 303 shift to the DLP mode in which direct communication is performed in the infrastructure network shown in FIG. . At this time, the first station 302 and the second station 303 can communicate directly without going through the access point 301.
The first to third stations 302 to 304 are, for example, a camera having a hardware configuration similar to that shown in FIG. 2, a PC, a PDA having a hardware configuration similar to that shown in FIG. A device having a wireless communication function, such as a mobile phone or a printer. The hardware configuration of the access point 301 is the same as that shown in FIG. 4, for example.

FIG. 6 is a diagram showing an example of an operation procedure when shifting to the direct communication mode in which communication is performed directly between stations as shown in FIG. 5B and an operation procedure when returning from the direct communication mode. is there.
FIG. 6 shows an example in which the first station (STA1) 302 becomes an initiator in DLP and the second station (STA2) becomes a recipient in DLP, and the operation when shifting to the DLP mode is shown as an example. The procedure is as follows.

  First, the first station (STA1) 302 transmits a DLP request signal (DLP_req signal) to the access point (AP) 301 in order to establish direct communication with the second station (STA2) 303 ( Step S501). The access point (AP) 301 that has received the DLP request signal transfers a signal (DLP_req signal) having the same contents as the DLP request signal to the second station (STA2) 303 (step S502).

  The second station (STA2) 303 that has received the DLP request signal transmits a signal having the content “success” or “refused” as a DLP response signal (DLP_res signal) that is a response signal of the DLP request signal to the access point ( (AP) 301 (step S503). The access point (AP) 301 that has received the DLP response signal transfers a signal (DLP_res signal) having the same content as the DLP response signal to the first station (STA1) 302 (step S504). When a signal having the content “success” is received as a DLP response signal from the access point (AP) 301, the first station (STA 1) 302 thereafter communicates directly with the second station (STA 2) 303. It becomes possible to shift to the mode and perform direct communication.

  When data (Data) is transmitted from the first station (STA1) 302 to the second station (STA2) 303 (step S505), the second station (STA2) 303 receiving the data A data reception confirmation signal (Ack signal) is transmitted to the station (STA1) 302 (step S506). Thereafter, direct communication is continued between the first station (STA1) 302 and the second station (STA2) 303.

  When the direct communication performed as described above is terminated, the first station (STA1) 302 transmits a DLP_teardwn signal to the access point (AP) 301. The access point (AP) 301 that has received the DLP_teardwn signal transfers a signal (DLP_teardwn signal) having the same content as the DLP_teardwn signal to the second station (STA2) 303. Thus, when the second station (STA2) 303 receives the DLP_teardwn signal, the direct communication mode ends.

  Next, an example of a method for changing the valid time of discovery information (device information) performed by the first station (STA1) 302 serving as an initiator will be described with reference to the flowchart of FIG. In this case, it is assumed that the access point (AP) 301 has already been activated when the first station (STA1) 302 connects to the access point (AP) 301. Further, it is assumed that the first station (STA1) 302 and the second station (STA2) 303 are already connected to the access point (AP) at the time of issuing the DLP request.

  In FIG. 7, first, a power-on process for starting the power of the first station (STA1) 302 is performed. After starting the power supply, it is determined whether or not the communication mode has been set by the operation of the operation unit 204 by the user (step S601). When the communication mode is set, a connection operation in a wireless section such as association or authentication is performed on the access point (AP) 301 (step S602). When the connection operation in the wireless section is completed, the IP number of the access point (AP) 303 is assigned by the DHCP server built in the access point (AP) 301 (step S603).

  When the connection at the TCP / IP layer is completed, the UPnP protocol, which is the upper layer, is executed, and the Advertise signal for notifying the station of the connected network, etc., using its broadcast packet etc. Is issued (step S604). For example, the initial value of the valid time of discovery information issued by this Advertise signal is set to 30 seconds.

  Thereafter, it is monitored whether or not transmission of a captured image is instructed by a user operation (step S605). When an image transmission instruction to the second station 303 is performed, a DLP request signal is transmitted to the second station 303 via the access point (AP) 301 prior to starting direct communication with the second station 303. (Step S606). When the DLP request signal (DLP_req signal) is transmitted, the effective time of the discovery information is set to a time (for example, 10 minutes) corresponding to the time for using the DLP mode, which is longer than before the start of the DLP mode transition processing, and refreshed. A command (Refresh signal) is issued (step S607). Then, a DLP response signal (DLP_res signal) is received from the second station 303 via the access point 301 (step S608).

  When the content of this DLP response signal is “success” (Yes in step S608), the process proceeds to the direct communication mode (DLP mode) (step S609). After shifting to the direct communication mode in this way, the first station 302 performs direct communication with the second station 303. On the other hand, when the content of the DLP response signal is “refused”, a refresh command (Refresh signal) is issued in order to return the valid time of the discovery information to the initial value of 30 seconds (step S612).

  Thereafter, when the use time of the DLP mode ends and communication ends, the first station 302 transmits a DLP_teardwn signal (step S610), and ends the direct communication mode (step S611). Then, a refresh command (Refresh signal) is issued in order to return the effective period of the discovery time to the initial value of 30 seconds (step S612).

  If no transmission instruction is given in step S605, it is checked whether or not the effective time of discovery information is approaching (step S613). When the effective time is approaching, a refresh command (Refresh signal) is issued to update the effective time and return the effective time of the discovery information to the initial value of 30 seconds (step S614), and the process returns to step S605 again. .

  On the other hand, if the effective time has not been approached, it is determined whether or not the power button has been detected to be off (step S615). If it is determined that the power button is not turned off (OFF), the process returns to step S605. On the other hand, if the power button is detected to be off (OFF), a UPnP protocol discovery cancel command (Cancel signal) is issued (step S616), and then the wireless link disconnection process is executed (step S617). A power shut-off process for turning off (OFF) is executed, the power is turned off (step S618), and the process ends.

  Next, an example of a method for changing the valid time of discovery information performed by the second station (STA2) 303, which is a recipient, will be described using the flowchart of FIG. Here, as a premise, it is assumed that the access point (AP) 301 has already been activated when the second station (STA) 303 connects to the access point (AP) 301. Further, it is assumed that the first station (STA1) 302 and the second station (STA2) 303 are already connected to the access point (AP) at the time of receiving the DLP request.

  In FIG. 8, first, a power-on process for starting the power of the second station (STA2) 303 is performed. After starting the power supply, after starting the power supply, it is determined whether or not the communication mode is set by the operation of the operation unit by the user (step S701). When the communication mode is set, a connection operation in a wireless section such as association or authentication is performed for the access point (AP) 301 (step S702). When the connection operation in the wireless section is completed, the IP number of the access point (AP) 303 is assigned by the DHCP server built in the access point (AP) 301 (step S703).

  When the connection at the TCP / IP layer is completed, the UPnP protocol, which is the upper layer, is executed, and the Advertise signal for notifying the station of the connected network, etc., using its broadcast packet etc. Is issued (step S704). For example, the initial value of the valid time of discovery information issued by this Advertise signal is set to 30 seconds.

  Next, it is determined whether or not a DLP request signal (DLP_req signal) is received from the access point (AP) 301 (step S705). When the DLP request signal (DLP_req signal) is not received (No in step S705), it is determined whether the effective time of the discovery information is approaching (step S715).

  On the other hand, when a DLP request signal (DLP_req signal) is received (Yes in step S705), the requesting station (first station 302 in this example) is detected from the received DLP request, and the direct communication mode (DLP) is detected. It is determined whether or not communication in (mode) can be accepted (step S706). As a result of this determination, if it is possible to accept communication in the direct communication mode (DLP mode), a refresh command (Refresh signal) is received from the requesting first station (STA1) 302 (step S707). ).

  Then, the valid time of the discovery information included in the received refresh command is cited, and a refresh command (Refresh signal) is issued (as a refresh command issued by the second station (STA2) 303) (step S708) ( Here, the effective time is 10 minutes). Then, a DLP response signal (DLP_res signal) indicating “success” is transmitted to the first station (STA1) 302 via the access point (AP) 301 (step S709). Thereafter, the process shifts to the direct communication mode (DLP mode) (step S710). After shifting to the direct communication mode, the second station 303 performs direct communication with the first station 302.

  After that, when the second station (STA2) 303 receives the DLP_teardwn signal (step S711), the second station (STA2) 303 ends the direct communication mode (step S712), and returns the effective period of the discovery time to the initial value of 30 seconds. A refresh command (Refresh signal) is issued (step S713).

  If it is determined in step S706 that communication in the direct communication mode (DLP mode) cannot be accepted, a DLP response signal (DLP_res signal) indicating “refuse” is transmitted to the access point (AP). It is issued to 301 (step S714). Next, it is determined whether or not the effective time of the discovery information is approaching (step S715). If it is determined that the effective time is approaching, the effective time is updated, and a refresh command (Refresh signal) is issued to return the effective time of the discovery time to the initial value of 30 seconds (step S716). ), The process returns to step S705 again.

  If the expiration date is not approaching in the step S715, it is determined whether or not the power button is turned off (step S717). As a result of the determination, if the power button is not turned off (OFF), the process returns to step S705. On the other hand, when it is detected that the power button is turned off (OFF), a discovery cancel command (Cancel signal) is issued (step S718), and then a radio link disconnection process is executed (step S719). Thereafter, a power shutdown process for turning off the power is executed (step S720), and the process is terminated.

As described above, in this embodiment, before performing communication in the direct communication mode (DLP mode), the first station 302 serving as the initiator changes the validity period of the discovery information and changes to the second serving as the recipient. The station 303 also uses the value to make the validity period of the discovery information the same as that in the first station 302, thereby preventing the discovery information from being overwritten in the direct communication mode for the station with a lot of traffic. It is possible to prevent a discovery search from being leaked from a terminal such as the third station (STA3) 304 that is not communicating in the direct communication mode.
Further, even if communication is performed in the direct communication mode for a time longer than the device information valid time set first, it is possible to prevent the device information valid time from running out.

(Other embodiments of the present invention)
In order to operate various devices to realize the functions of the above-described embodiments, program codes of software for realizing the functions of the above-described embodiments are provided to an apparatus or a computer in the system connected to the various devices. What is implemented by operating the various devices according to a program supplied and stored in a computer (CPU or MPU) of the system or apparatus is also included in the scope of the present invention.

  In this case, the program code of the software itself realizes the functions of the above-described embodiments, and the program code itself and means for supplying the program code to the computer, for example, the program code are stored. The recorded medium constitutes the present invention. As a recording medium for storing the program code, for example, a flexible disk, a hard disk, an optical disk, a magneto-optical disk, a CD-ROM, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

  Further, by executing the program code supplied by the computer, not only the functions of the above-described embodiments are realized, but also the OS (operating system) or other application software in which the program code is running on the computer, etc. It goes without saying that the program code is also included in the embodiment of the present invention even when the functions of the above-described embodiment are realized in cooperation with the embodiment.

Further, after the supplied program code is stored in the memory provided in the function expansion board of the computer or the function expansion unit connected to the computer, the CPU provided in the function expansion board or function expansion unit based on the instruction of the program code Needless to say, the present invention includes a case where the functions of the above-described embodiment are realized by performing part or all of the actual processing.
As described above, according to the above-described embodiment, it is possible to prevent the discovery function information managed by other communication devices from expiring even when the mode is shifted to the predetermined mode.
Further, since the valid time of the device information in the predetermined mode is made longer than the valid time of the device information in the mode other than the predetermined mode, the device information is updated every time the mode is returned from the predetermined mode. There is no need to do. Thereby, the process for returning from the predetermined mode can be performed accurately and promptly.

It is a figure which shows the 1st Embodiment of this invention and shows an example of a structure of a radio | wireless communication network system. 1 is a block diagram illustrating an example of a configuration of a camera according to a first embodiment of this invention. 5 is a flowchart illustrating an example of a discovery operation according to the first embodiment of this invention. 1 is a block diagram illustrating an example of a configuration of a computer system disposed in a PC according to a first embodiment of this invention. It is a figure which shows the 2nd Embodiment of this invention and shows an example of a structure of a radio | wireless communication network system. It is a figure which shows the 2nd Embodiment of this invention, and shows an example of the operation | movement procedure at the time of shifting to direct communication mode, and the operation | movement procedure at the time of returning from direct communication mode. It is a flowchart which shows the 2nd Embodiment of this invention and demonstrates an example of the change method of the effective time of the discovery information in a 1st station. It is a flowchart which shows the 2nd Embodiment of this invention and demonstrates an example of the change method of the effective time of the discovery information in a 2nd station. It is a figure which shows the prior art and shows the operation | movement procedure at the time of notifying the information of a device.

Explanation of symbols

101 Camera 102 PC
201 Host CPU
202 Memory 203 Imaging Unit 204 Operation Unit 205 Wireless Unit 301 Access Points 302 to 304 Station

Claims (18)

For the other communication device on the network, a communication apparatus that notifies the device information including the expiration date information and the information related to the own device,
First notification means for notifying device information in response to participation in the network ;
First determination means for determining whether or not to shift to a power saving mode for reducing power consumption in a communication unit of the communication apparatus after device information is notified by the first notification means;
Wherein when it is determined that the process proceeds to the power saving mode by the first determining means, de the expiration date included in the device information, the first notification means by longer than the effective date included in the notification device information Expiration A second notification means for notifying device information changed to
A third notification means for canceling the power saving mode in conjunction with the long expiration date after the change and re-notifying device information;
A communication apparatus comprising: The communication apparatus according to claim 1, wherein the third notification unit notifies the device information changed to an expiration date shorter than the expiration date included in the device information notified by the second notification unit. The communication apparatus according to claim 2, wherein the third notification unit notifies the device information changed to the same expiration date as the expiration date of the device information notified by the first notification unit. The communication apparatus according to any one of claims 1 to 3, wherein the second notification unit notifies the device information changed to the long expiration date before the shift to the power saving mode. . Control means for controlling the communication device;
5. The communication apparatus according to claim 1, wherein when the mode is shifted to the power saving mode, a clock speed of the control unit is decreased. 6. Based on the operation by the user, a second determination means for determining whether to cancel the power saving mode,
Said third notifying means, wherein even when it is released Then determine the power saving mode by the second determining means, wherein, characterized in that the re-notification device information by releasing the power saving mode Item 6. The communication device according to any one of Items 1 to 5 . The communication apparatus according to any one of claims 1 to 6, wherein the first, second, and third notification means are means for broadcasting device information on a network. Whichever of the first communication mode in which communication is performed between a plurality of communication devices via an access point and the second communication mode in which communication is performed directly between a plurality of communication devices without passing through the access point A communication device for performing communication in any communication mode,
First notification means for notifying other communication devices on the network of device information including information about the device itself and an expiration date of the information;
First determination means for determining whether or not to shift from the first communication mode to the second communication mode;
If it is determined that the process proceeds to the second communication mode by said first determining means, the expiration date included in the device information, from the expiration date included in the device information when operating in the first communication mode A second notification means for notifying the device information that has a long expiration date and changed to the expiration date according to the time of operation in the second communication mode ;
A communication apparatus comprising: It said first, second notification hand stage, the communication apparatus according to claim 8, characterized in that via the access point notifies the device information to other communication devices. Receiving means for receiving device information from another communication device via the access point;
Updating means for updating the valid time included in the device information notified by the own device based on the valid period included in the device information received by the receiving means;
The communication apparatus according to claim 8 , wherein the communication apparatus includes: Said updating means, and updates the effective time included in the device information received by the receiving means, the effective time as the effective time included in the device information when the device itself notified the same The communication device according to claim 10 . Second determination means for determining whether or not to end communication in the second communication mode;
Device information that has been changed to an expiration date shorter than the expiration date included in the device information notified by the second notification means when it is determined by the second determination means to end communication in the second communication mode. A third notification means for re-notifying
The communication apparatus according to claim 8, wherein the communication apparatus includes: 13. The communication apparatus according to claim 12, wherein the third notification unit re-notifies the device information that has been changed to the same expiration date as the expiration date of the device information notified by the first notification unit. Request means for requesting another communication apparatus that is communicating via the access point in the first communication mode to shift from the first communication mode to the second communication mode. ,
12. The device according to claim 8, wherein the second notification unit notifies the device information whose expiration date has been changed between when the request is made to the request unit and when a response to the request is received. The communication apparatus of any one of Claims. When a response indicating rejection of the transition to the second communication mode is received as a response to the request by the request unit, the device information including the expiration date before the change is re-notified by the second notification unit. The communication apparatus according to claim 14, further comprising a fourth notification unit. A communication method of a communication device that notifies device information including information about the device itself and an expiration date of the information by a discovery function,
A first notification step of notifying the device information for the other communication device,
A judgment step after the notification of the device information, which determines whether to shift to the power saving mode for reducing power consumption in the communication unit of the communication device in the first notification step,
If it is determined that the process proceeds to the power saving mode by the determining step, the expiration date included in the device information, and changes to the first notification longer expiration than the effective date included in the notification device information in step A second notification step for notifying device information;
A third notification step of canceling the power saving mode in conjunction with the long expiration date after the change and re-notifying device information;
A communication method characterized by comprising: Whichever of the first communication mode in which communication is performed between a plurality of communication devices via an access point and the second communication mode in which communication is performed directly between a plurality of communication devices without passing through the access point A communication method of a communication device that performs communication in any communication mode,
A first notification step of notifying other communication devices of device information including information about the device itself and an expiration date of the information;
A determination step of determining whether or not to shift from the first communication mode to the second communication mode;
When it is determined in the determination step that the mode is shifted to the second communication mode, the expiration date included in the device information is set to an expiration date longer than the expiration date included in the device information during operation in the first communication mode. A second notification step of notifying device information changed to an expiration date according to a time of operation in the second communication mode;
A communication method characterized by comprising: A computer program for causing a computer to execute each step of the communication method according to claim 16 or 17.

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