JP6369197B2 - Communication terminal, communication control method and program - Google Patents

Description

  The present invention relates to a communication terminal, a communication control method, and a program thereof, and more particularly, to a communication terminal, a communication control method, and a program that can communicate autonomously between terminals.

  Inter-terminal communication that can communicate between terminals in an autonomous and distributed manner is to share each other's information before the restoration of the infrastructure network when communication via the mobile communication network becomes difficult due to a failure of the base station or upstream network It is expected as a method.

  As an example of inter-terminal communication, Patent Document 1 and Non-Patent Document 1 describe an epidemic method for sharing content between nodes. In the content sharing between nodes by the epidemic method, first, an SV (Summary Vector) message including a content list held by the own node is periodically publicized to surrounding nodes. Next, the peripheral node that has received the SV message compares the content held by the node that transmitted the SV message with the content held by itself. The peripheral nodes transmit and receive content to and from the node that transmitted the SV message so that the compared difference disappears, and advance content sharing between the nodes.

  There are two types of content sharing between nodes in the epidemic system: pull type and push type.

  In the push type, the second node that has received the SV message of the first node, as a result of the content comparison, sets the content held by the second node and not held by the first node to the first node. It is a type to share contents by sending.

  In the pull type, when the second node that has received the SV message of the first node, as a result of the content comparison, the content that the second node does not hold and the first node holds in the request message Request to other nodes. The first node that has received the request message is of a type that shares the content by transmitting the requested content to the second node.

International Publication No. 2011/071045 JP 2010-004136 A JP 2007-336360 A

M.M. Akdere, C.I. C. Belgin, O .; Gerdaneri, I. et al. Korpeoglu, O .; Ulusoy and U.S. Ceintmel, “A comparison of epidemiological algorithms in wireless sensor networks,” Computer Communications, Vol. 29, Issue 13-14, pp. 2450-2457, Aug. 2006.

  In communication methods that perform inter-terminal communication in an autonomous and distributed manner, including the epidemic method, there is a case in which content is transmitted redundantly in order to increase the success rate of content transmission / reception between terminals. This wastes network resources between terminals. An example will be described with reference to FIGS.

  FIG. 25 is a diagram illustrating an example (first case) in which each node that receives an SV message transmits content to the node that transmitted the SV message. The first case is an example in which the second node and the third node that have received the SV message of the first node respectively transmit the same content to the first node.

  When receiving the content transmitted from the second node or the third node, the first node cannot identify whether the received content is the same until the reception is completed and stored. For this reason, the first node cannot stop receiving the duplicate content.

  FIG. 26 is a diagram illustrating an example (second case) in which the node that has received the SV message transmits a request message to the node that has transmitted the SV message. In the second case, the first node requesting the content resends the request message until reception of the content requested by the first node is completed in preparation for the request message dropping.

  Even if the request message transmitted by the first node is received by the second node without being dropped, and the second node transmits the requested content to the first node, the first node The request message is output again to the second node until the reception of is completed. As a result, the second node transmits the content in duplicate in response to the next request message. Until the reception of the content is completed, the first node cannot identify whether the content received from the second node is being received or has been received. Cannot cancel reception.

  An object of the present invention is to provide a communication terminal, a communication control method, and a program that can reduce waste of network resources due to the duplicate transmission of content, which is the above-described problem.

  The communication terminal according to the present invention includes a content reception processing unit that receives the content identifier before receiving the content in a communication session of communication between terminals that transmits and receives a content identifier corresponding to the content, and other than the received content identifier. A content reception control unit that rejects reception of the content corresponding to the received content identifier.

  The communication control method of the present invention is a communication session for communication between terminals that transmits and receives a content identifier corresponding to a content, receives the content identifier before receiving the content, and receives another communication session for the received content identifier. Is present, the reception of the content corresponding to the received content identifier is rejected.

  The program of the present invention receives a content identifier before receiving the content in a communication session of communication between terminals that transmits and receives a content identifier corresponding to the content to a computer, and performs other communication on the received content identifier. A program for executing, when there is a session, rejecting reception of the content corresponding to the received content identifier.

  According to the present invention, waste of network resources due to duplicate transmission of content can be reduced.

It is a figure which shows the outline | summary of the communication between terminals by the communication terminal which concerns on embodiment of this invention. It is a block diagram which shows the structure of the communication terminal which concerns on the 1st Embodiment of this invention. It is a flowchart which shows operation | movement of the communication terminal which concerns on the 1st Embodiment of this invention. It is a block diagram which shows the structure of the communication terminal which concerns on the 2nd Embodiment of this invention. It is a figure which shows the correspondence information preserve | saved at the correspondence information preservation | save part of the communication terminal which concerns on the 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the communication terminal which concerns on the 2nd Embodiment of this invention. FIG. 6 is a diagram illustrating an example in which a part of the correspondence information illustrated in FIG. 5 is deleted. It is a block diagram which shows the structure of the communication terminal which concerns on the 3rd Embodiment of this invention. It is a figure which shows the correspondence information preserve | saved at the correspondence information preservation | save part of the communication terminal which concerns on the 3rd Embodiment of this invention. It is a flowchart which shows operation | movement of the communication terminal which concerns on the 3rd Embodiment of this invention. It is a figure which shows the outline | summary of the communication between terminals by the communication terminal which concerns on embodiment of this invention. It is a block diagram which shows the structure of the communication terminal 200-1 which concerns on the 4th Embodiment of this invention. It is a block diagram which shows the structure of the communication terminal 100 which concerns on the 4th Embodiment of this invention. It is a flowchart which shows the 1st operation | movement which is a part of operation | movement in the communication terminal 200 which concerns on the 4th Embodiment of this invention. It is a flowchart which shows the 2nd operation | movement which is a part of operation | movement in the communication terminal 200 which concerns on the 4th Embodiment of this invention. It is a flowchart which shows operation | movement of the communication terminal 100 which concerns on the 4th Embodiment of this invention. It is a sequence diagram of the communication between terminals using the communication terminal which concerns on the 4th Embodiment of this invention. It is a block diagram which shows the structure of the communication terminal 400 which concerns on the 5th Embodiment of this invention. It is a block diagram which shows the structure of the communication terminal 300 which concerns on the 5th Embodiment of this invention. It is a flowchart which shows the 1st operation | movement which is a part of operation | movement in the communication terminal 400 which concerns on the 5th Embodiment of this invention. It is a flowchart which shows the 2nd operation | movement which is a part of operation | movement in the communication terminal 400 which concerns on the 5th Embodiment of this invention. It is a flowchart which shows the 1st operation | movement which is a part of operation | movement in the communication terminal 300 which concerns on the 5th Embodiment of this invention. It is a flowchart which shows the 2nd operation | movement which is a part of operation | movement in the communication terminal 300 which concerns on the 5th Embodiment of this invention. It is a sequence diagram of the communication between terminals using the communication terminal which concerns on the 5th Embodiment of this invention. It is a block diagram which shows the structure of the communication terminal 500 which concerns on the 6th Embodiment of this invention. It is a sequence diagram of the communication between terminals using the communication terminal which concerns on the 6th Embodiment of this invention. It is a figure which shows the hardware constitutions which implement | achieved the communication terminal in 1st-5th embodiment with the computer apparatus. It is a figure which shows the example which each node which received SV message transmits content to the node which transmitted SV message. It is a figure which shows the example which the node which received SV message transmits a request message to the node which transmitted SV message.

  Embodiments of the present invention will be described in detail with reference to the drawings. The communication terminal in this specification is intended for a mobile communication terminal.

  FIG. 1 is a diagram showing an overview of inter-terminal communication by a communication terminal according to an embodiment of the present invention. As shown in FIG. 1, the communication terminal 10 can communicate with the communication terminals 20-1 and 20-2 in an autonomous and distributed manner, and establishes a communication session between the communication terminals to transmit and receive content. The communication terminal 10 can establish a plurality of different communication sessions (communication session AB and communication session AC) between the communication terminals 20-1 and 20-2. Alternatively, a plurality of different communication sessions (communication session AB, communication session AB2) can be established between the communication terminal 10 and the communication terminal 20-1.

[First Embodiment]
FIG. 2 is a block diagram showing the configuration of the communication terminal according to the first embodiment of the present invention. In FIG. 2, a communication terminal 10 is a communication terminal that receives content, and a communication terminal 20-1 and a communication terminal 20-2 are communication terminals that transmit content.

  First, communication terminals 20-1 and 20-2 that transmit content according to the first embodiment will be described with reference to FIG. The communication terminal 20-1 and the communication terminal 20-2 have the same function. Hereinafter, the communication terminal 20-1 will be mainly described, and the communication terminal 20-2 will be appropriately described.

  The communication terminal 20-1 includes a communication unit (not shown), a content transmission processing unit 21, a content transmission control unit 22, and a content storage unit 23.

  The communication unit (not shown) has a function of communicating with other communication terminals by inter-terminal communication.

  The content transmission processing unit 21 has a function of establishing a communication session with the communication terminal 10 according to an instruction from the content transmission control unit 22. In FIG. 2, the communication terminal 20-1 establishes a communication session AB with the communication terminal 10, and the communication terminal 20-2 establishes a communication session AC with the communication terminal 10.

  Further, the content transmission processing unit 21 has a function of transmitting content and a content identifier corresponding to the content in the established communication session. Specifically, the content transmission processing unit 21 extracts content to be transmitted to the communication terminal 10 from the content stored in the content storage unit 23, and sets a content identifier corresponding to the content to be transmitted prior to content transmission. It transmits to the communication terminal 10. After transmitting the content identifier, the content transmission processing unit 21 transmits the extracted content to the communication terminal 10.

  For convenience of description of the first embodiment, the communication terminal 20-1 and the communication terminal 20-2 each transmit a content identifier corresponding to the same content to the communication terminal 10, but the transmission timing of the content identifier is the communication terminal. 20-2 is assumed to be after the communication terminal 20-1.

  Next, the communication terminal 10 that receives content in the first embodiment will be described with reference to FIG. The communication terminal 10 includes a communication unit (not shown), a content reception processing unit 11, and a content reception control unit 12.

  A communication unit (not shown) of the communication terminal 10 has a function of communicating with other communication terminals in the same manner as the communication terminal 20-1.

  The content reception processing unit 11 has a function of establishing a communication session with the communication terminal 20-1 and the communication terminal 20-2 according to an instruction from the content reception control unit 12, respectively. In FIG. 2, the communication terminal 10 establishes a communication session AB with the communication terminal 20-1, and establishes a communication session AC with the communication terminal 20-2.

  Furthermore, the content reception processing unit 11 has a function of receiving content and a corresponding content identifier in an established communication session.

  The content reception control unit 12 has a function of controlling reception of content transmitted from the communication terminals 20-1 and 20-2. Specifically, the content reception control unit 12 checks whether there is another communication session for the received content identifier, and if there is another communication session, rejects reception of the content corresponding to the content identifier. To do. If there is no other communication session, the content reception control unit 12 instructs the content reception processing unit 11 to receive the content.

  For example, if the communication session is a connection establishment type such as TCP, the content reception control unit 12 may instruct the communication unit (not shown) to forcibly close the connection. Alternatively, the reception control unit 12 may create a message indicating that the content is rejected and instruct a communication unit (not shown) to transmit the message to a communication terminal that stops transmission of the content.

  Here, the content is information data such as video, image, sound, text, or program, and the content identifier is information data for identifying the content.

  FIG. 3 is a flowchart showing the operation of the communication terminal according to the first embodiment of the present invention. As illustrated in FIG. 2, it is assumed that the communication terminal 10 receives the same content from the communication terminals 20-1 and 20-2 in the communication session AB and the communication session AC, respectively. Further, it is assumed that the communication terminal 20 receives the content identifier earlier than the communication terminal 20-2 of the communication session AC.

  The content reception processing unit 11 of the communication terminal 10 receives the content identifier before receiving the content in the communication session (S11). Specifically, in the example of the first embodiment, the content reception processing unit 11 receives the content identifier by the communication session AB, and then receives the content identifier by the communication session AC.

  The content reception control unit 12 of the communication terminal 10 checks whether another communication session exists for the received content identifier (S12). When the content identifier is received in the preceding communication session AB, there is no other communication session (No in S12), but when the content identifier is received in the communication session AC, the communication session AB exists (Yes in S12).

  The content reception control unit 12 rejects the reception of the content corresponding to the content identifier of the received communication session AC in order to avoid receiving the content of the communication session AC that overlaps the content of the communication session AB (S13). When there is no other communication session (No in S12), the content reception control unit 12 instructs the content reception processing unit 11 to receive content (S14).

  As described above, according to the communication terminal 10 of the first embodiment, it is possible to prevent duplicate transmission / reception of contents and reduce waste of network resources. The reason is that the content reception control unit 12 of the communication terminal 10 checks whether another communication session exists for the received content identifier, and if there is another communication session, corresponds to the content identifier of the communication session. This is because the reception of the content to be rejected is rejected.

[Second Embodiment]
Next, a communication terminal according to a second embodiment of the present invention will be described with reference to FIG. 4, FIG. 5, and FIG. The communication terminal 30 according to the second embodiment is a communication terminal that receives content, and is different from the communication terminal 10 according to the first embodiment in that a correspondence information storage unit 33 is provided. Hereinafter, portions that overlap with the description of the communication terminal according to the first embodiment will be briefly described.

  FIG. 4 is a block diagram illustrating a configuration of the communication terminal according to the second embodiment. In FIG. 4, the communication terminal 30 of the second embodiment includes a correspondence information storage unit 33 in addition to the configuration of the communication terminal 10 of the first embodiment. The content reception control unit 32 has a function of referring to the correspondence information storage unit 33.

  The correspondence information storage unit 33 of the communication terminal 30 is connected to the content reception processing unit 11 and the content reception control unit 32, respectively, and has a function of storing correspondence information between the content identifier received for each communication session and the communication session.

  FIG. 5 is a diagram illustrating an example of correspondence information stored in the correspondence information storage unit 33. As shown in FIG. 5, the correspondence information includes data items indicating the correspondence between communication sessions and content identifiers. The correspondence information in FIG. 5 indicates that the content identifier ID_X has been received in the communication session AB and the content identifier ID_Y has been received in the communication session AC. In other words, it indicates that the communication terminal 10 is currently receiving the content corresponding to the content identifier in the communication session, or plans to receive the content in the future.

  The content reception control unit 32 has a function of referring to the correspondence information stored in the correspondence information storage unit 33 and checking whether there is another communication session related to the content identifier. Furthermore, when there is another communication session related to the content identifier, the content reception control unit 32 rejects reception of the content corresponding to the content identifier received later.

  FIG. 6 is a flowchart showing the operation of the communication terminal according to the second embodiment of the present invention. Hereinafter, the description of the operation of the communication terminal of the second embodiment will be described centering on the difference from the operation of the first embodiment, and detailed description of the same operation as that of the first embodiment will be omitted. .

  As shown in FIG. 6, after the content reception processing unit 11 of the communication terminal 30 receives the content identifier (S11), the content reception control unit 32 determines whether another communication session exists for the received content identifier. Check (S12).

  Reference to the correspondence information storage unit 33 by the content reception control unit 32 will be described with reference to the example of FIG. When the content reception processing unit 11 receives the content identifier ID_X in the communication session AD, the content reception control unit 32 determines whether a communication session different from the communication session AD exists for the received content identifier ID_X, or the correspondence information in FIG. Refer to At this time, the correspondence information storage unit 13 stores {communication session, content identifier} = {AB, ID_X} as in the correspondence information shown in FIG. 5, and there is a different communication session for the content identifier ID_X. This indicates that the communication terminal 10 has already received or plans to receive the content corresponding to the content identifier ID_X in the communication session AB. Therefore, the content reception control unit 32 rejects the reception of the content corresponding to the content identifier received in the communication session AD in order to avoid duplication of content (S13).

  Also, unlike the above example, when the content reception processing unit 11 receives the content identifier ID_Z in the communication session AD, there is no communication session corresponding to the content identifier ID_Z in the correspondence information illustrated in FIG. Therefore, the content reception control unit 32 stores the correspondence information between the received content identifier and the communication session in the correspondence information storage unit 33 (S13B), and then receives the content corresponding to the received content identifier ( S14).

  In the above description, the communication session and the content identifier information are added to the correspondence information of the correspondence information storage unit 33. However, after the reception of the content in the communication session is completed, the correspondence information of the correspondence information storage unit 33 is deleted. Also good.

  FIG. 7 is a diagram illustrating an example in which the correspondence information in FIG. 5 is deleted. The deletion of the correspondence information may delete the communication session information as in the upper part of the correspondence information, or may delete both the communication session and the content identifier as in the middle part of the correspondence information. In the deletion of the correspondence information in the correspondence information storage unit 33, the content reception processing unit 11 deletes the content identifier and communication session information corresponding to the content in the correspondence information of the correspondence information storage unit 33 in response to the completion of content reception. .

  As described above, according to the communication terminal 30 of the second embodiment, it is possible to prevent duplicate transmission / reception of contents as in the first embodiment and reduce waste of network resources.

[Third Embodiment]
A communication terminal according to the third embodiment of the present invention will be described with reference to FIG. 8, FIG. 9, and FIG. FIG. 8 is a block diagram illustrating a configuration of a communication terminal according to the third embodiment. In FIG. 8, a communication terminal 40 according to the third embodiment is a communication terminal that receives content, and further includes a content storage unit 44 in the configuration of the communication terminal 30 according to the second embodiment.

  With the addition of the content storage unit 44 in the communication terminal 40, the content reception processing unit 41 has a function of storing content in the content storage unit 44 in addition to the function of the content reception processing unit 11, and the correspondence of the correspondence information storage unit 43. A function of deleting information and a function of registering information on the storage status of content in the correspondence information storage unit 43 are provided. In addition to the function of the content reception control unit 32, the content reception control unit 42 has a function of referring to the content storage status of the correspondence information storage unit 43. The correspondence information stored in the correspondence information storage unit 43 includes an item of content storage status.

  The content storage unit 44 of the communication terminal 40 is connected to the content reception processing unit 41, the content reception control unit 42, and the correspondence information storage unit 43, respectively, and has a function of storing content that has been received for each communication session.

  Content storage in the content storage unit 44 is executed by the content reception processing unit 41. Accumulation in the content storage unit 44 is started after the content reception processing unit 41 starts receiving the content, and the storage is completed after the content reception is completed. The content reception processing unit 41 may start accumulation in the content storage unit 44 after the completion of content reception.

  After storing the content in the content storage unit 44, the content reception processing unit 41 registers information on the storage status of the content in the correspondence information in the correspondence information storage unit 43.

  FIG. 9 is a diagram illustrating an example of correspondence information stored in the correspondence information storage unit 43. In FIG. 9, the item of correspondence information includes a content name and a storage status as new items in addition to the communication session and the content identifier. The upper part of the correspondence information indicates that the content X corresponding to the content identifier ID_X is before the reception or the completion of the reception of the content X in the communication session AB. At this time, the content X represents a situation where not all content is stored in the content storage unit 44. The middle part of the correspondence information indicates that the content Y corresponding to the content identifier ID_Y has been stored in the content storage unit 44. The communication session information is deleted when the storage of the content Y is completed.

  Note that, as shown in the lower part of the correspondence information, the content identifier may be deleted together with the communication session when the storage of the content Z is completed. When the content to be received is already stored in the content storage unit 44, the content reception control unit 42 of the communication terminal 40 can prevent content duplication by referring to the correspondence information in the correspondence information storage unit 43. Become.

  FIG. 10 is a flowchart showing the operation of the communication terminal according to the third embodiment of the present invention. Hereinafter, the operation of the communication terminal according to the third embodiment will be described focusing on the differences from the operations of the first and second embodiments, and the same operation as that of the third embodiment will be described in detail. Is omitted.

  In the communication terminal 40 according to the third embodiment, after receiving the content identifier (S21), the content reception control unit 42 has another communication session corresponding to the received content identifier or the content has been saved. It is confirmed with reference to the correspondence information storage unit 43 (S22). If another communication session exists (Yes in S23) or the content has been saved (Yes in S24D), the content reception control unit 42 rejects reception of the content corresponding to the received content (S13). . Note that the order of the conditions in S23 and S24 may be reversed. In S22, if there is another communication session corresponding to the received content identifier, confirmation of whether the content has been saved may be omitted.

  When there is no other communication session (No in S23) and the content is not already saved (No in S24), the content reception control unit 42 stores correspondence information between the received content identifier and the communication session. Register in the unit 43 (S13B).

  Subsequently, the content reception processing unit 41 starts to receive content corresponding to the received content identifier (S14). Thereafter, the content reception processing unit 41 accumulates the content in the content storage unit 44, and completes the storage of the content after the content reception is completed (S15). Furthermore, the content reception processing unit 41 registers the content storage status in the correspondence information of the correspondence information storage unit 43 (S16), and deletes the information of the communication session that received the content from the correspondence information. The content reception control unit 42 may delete the communication session information from the correspondence information stored in the correspondence information storage unit 43 in addition to the content reception processing unit 41.

  As described above, according to the communication terminal 40 of the third embodiment, similar to the communication terminal 10 of the first embodiment and the communication terminal 30 of the second embodiment, duplicate transmission / reception of contents is prevented, and the network Resource waste can be reduced.

  In the communication terminal 40 of the third embodiment, the content storage status in the content storage unit is registered in the correspondence information of the correspondence information storage unit 43. Thereby, even when the content reception processing unit 11 receives the same content identifier as the content identifier deleted from the correspondence information, the existence of duplicate content can be investigated by examining the correspondence information in the correspondence information storage unit 43.

[Fourth Embodiment]
A communication terminal according to a fourth embodiment of the present invention will be described with reference to FIG. 11, FIG. 12, and FIG. A communication terminal according to the fourth embodiment of the present invention is a communication terminal to which an epidemic method using inter-terminal communication is applied. As illustrated in FIG. 11, the communication terminal 100 can perform inter-terminal communication in an autonomous and distributed manner with the communication terminal 200-1 and the communication terminal 200-2, and between the communication terminal 200-1 and the communication terminal 200-2. Thus, different communication sessions (communication session AB and communication session AC) can be established. The communication terminal according to the fourth embodiment will be described as an example of an epidemic push type based on inter-terminal communication.

  The communication terminal 100 will be described below as a communication terminal that receives content, and the communication terminal 200-1 and the communication terminal 200-2 are described as communication terminals that transmit content.

  FIG. 12 is a block diagram showing a configuration of a communication terminal according to the fourth embodiment of the present invention. Since the communication terminal 200-1 and the communication terminal 200-2 have the same configuration, the configuration of the communication terminal 200-1 will be described below as a representative.

  Referring to FIG. 12, a communication terminal 200-1 according to the fourth embodiment of the present invention includes a communication unit 210, an arithmetic processing unit 220, and a storage unit 230. The communication unit 210 has the same function as the communication unit 110 of the communication terminal 100 described later.

  The arithmetic processing unit 220 includes an SV message receiving unit 220D, a content transmission control unit 220E, and a content transmission processing unit 220F as functions realized by the arithmetic processing unit 220. Note that each function realized by the arithmetic processing unit 220 may operate in parallel.

  The content transmission control unit 220E has a function of controlling content transmission. When the content transmission control unit 220E receives the SV message from the communication terminal 100, the content transmission control unit 220E receives a list of contents held by the communication terminal 100 included in the SV message from the SV message reception unit 220D, and receives the communication terminal 200- The content is compared with the content stored in one content storage unit 230A. Subsequently, the content transmission control unit 220E extracts the content stored in the communication terminal 200 that is not held by the communication terminal 100 as content to be transmitted to the communication terminal 100.

  When there is no transmission content, the content transmission control unit 220E does nothing and returns to waiting for the SV message again. On the other hand, when there is transmission content, the content transmission control unit 220E instructs the content transmission processing unit 220F to start processing for transmitting the transmission content to the communication terminal 100, and returns to waiting for reception of the SV message.

  Here, when there are a plurality of transmission contents to be transmitted to the communication terminal 100, the content transmission processing unit 220F may read out each transmission content from the content storage unit 230A and perform transmission processing on each content in parallel. Good. Further, the content transmission control unit 220E may return to waiting for the reception of the SV message without waiting for the content transmission processing unit 220F to end the processing.

  The content transmission processing unit 220F transmits the transmission content instructed by the content transmission control unit 220E to the communication terminal 100. The content transmission processing unit 220F instructs the communication unit 210 to establish a communication session with the communication terminal 100. Subsequently, the content transmission processing unit 220F instructs the communication unit 210 to transmit a transmission content notification including a content identifier corresponding to the transmission content to the communication terminal 100 using the established communication session.

  Here, the content transmission processing unit 220F may explicitly transmit the transmission content notification and the transmission content by dividing them into separate packets, but the transmission content notification and the transmission content use the same communication session. Send.

  Also, the content transmission processing unit 220F instructs the communication unit 210 to stop the transmission of the content when the transmission content is refused by the communication terminal 100 while the transmission content is being transmitted to the communication terminal 100. When the content transmission processing unit 220F completes the transmission of the content, the content transmission processing unit 220F ends the communication session and ends the transmission processing related to the content.

  The SV message receiving unit 220D transfers the content list included in the SV message to the content transmission control unit 220E.

  The storage unit 230 includes a storage device such as a hard disk or a memory, and has a function of storing various types of information used in processing in the arithmetic processing unit 220.

  The content storage unit 230A has a function of storing content received from other communication terminals and content of the own communication terminal 200-1.

  FIG. 13 is a block diagram illustrating a configuration of the communication terminal 100 that receives content. Referring to FIG. 13, a communication terminal 100 according to the fourth embodiment of the present invention includes a communication unit 110, an arithmetic processing unit 120, and a storage unit 130. The communication unit 110 has a function of communicating with other communication terminals. The communication unit 110 includes a wireless interface unit and peripheral circuits for performing wireless LAN communication defined by, for example, IEEE (Institut of Electrical and Electronics Engineers) 802.11, and an OS (for controlling them) (Operating System) kernel module, driver, and the like.

  The communication unit 110 may perform network control such as detection of other communication terminals and routing. The communication protocol with other terminal communication is arbitrary, and TCP (Transmission Control Protocol), UDP (User Datagram Protocol), etc. may be used.

  The arithmetic processing unit 120 includes an SV message transmission unit 120A, a content reception control unit 120B, and a content reception processing unit 120C as functions realized by the arithmetic processing unit 120. Each function realized by the arithmetic processing unit 120 may operate in parallel.

  The SV message transmission unit 120A creates a list of contents stored by the content storage unit 130A as an SV message and instructs the communication unit 110 to publicize it to surrounding nodes.

  The SV message transmitting unit 120A may cause the SV message to be transmitted at a constant cycle, or may dynamically change the transmission cycle according to the network environment or the like. In addition, the SV message transmission unit 120A may instruct the communication unit 110 to publicize the SV message by broadcast communication, or may instruct the communication unit 110 to transmit to each peripheral node by unicast communication. Also good.

  The content reception control unit 120B has a function of controlling content reception. That is, when the content reception control unit 120B receives the transmission content notification through the communication session after establishing the communication session with the communication terminal 200-1 and the communication terminal 200-2, it determines whether to receive the content in the communication session. to decide.

  Specifically, the content reception control unit 120B checks whether content corresponding to the content identifier included in the transmission content notification is stored in the content storage unit 130A. Furthermore, the content reception control unit 120B checks whether the communication session corresponding to the content identifier is stored in the correspondence information storage unit 130B.

  The transmission content notification is a message transmitted from the other communication terminal to the own communication terminal, and includes a content identifier for the content transmitted in the communication session.

  Also, the content reception control unit 120B, when there is no content corresponding to the content identifier in the content storage unit 130A and there is no other communication session corresponding to the received content identifier, the content reception control unit 120B Correspondence information with the communication session is stored in the correspondence information storage unit 130B.

  Subsequently, the content reception control unit 120B causes the content reception processing unit 120C to receive the content in the communication session, and returns to waiting for reception of the content identifier. At this time, the content reception control unit 120B may return to waiting for the reception of the content identifier without waiting for the processing of the content reception processing unit 120C to end.

  On the other hand, when content exists in content storage unit 130A or there is another communication session corresponding to the content being received, content reception control unit 120B rejects the reception of the content in the communication session.

  Regarding the rejection of content reception, when the communication session is a connection establishment type such as TCP, the content reception control unit 120B may instruct the communication unit 110 to forcibly close the connection. Alternatively, the content reception control unit 120B may create a message indicating rejection of the content and instruct the communication unit 110 to transmit the message to the communication terminal 200-1 or 200-2.

  The content reception processing unit 120C receives content using a communication session instructed by the content reception control unit 120B. When the content reception processing unit 120C has received the content, the content reception processing unit 120C stores the received content in the content storage unit 130A. Furthermore, the content reception processing unit 120C deletes the correspondence between the content and the communication session from the correspondence information storage unit 130B, closes the communication session, and ends the content reception process.

  However, if the content reception is stopped before the content has been received, the content reception processing unit 120C, in response to an instruction from the content reception control unit 120B, does not store the content, and the correspondence between the content and the communication session. Is deleted from the correspondence information storage unit 130B, the communication session is closed, and the process is terminated. For example, when the content packet cannot be received for a certain time or more, it is determined that the content reception is stopped.

  The storage unit 130 includes a content storage unit 130A and a correspondence information storage unit 130B, and has functions similar to those of the content storage unit 44 and the correspondence information storage unit 43 in the third embodiment, respectively.

  Next, the operation of the communication terminal according to the fourth embodiment will be described using FIG. 14A, FIG. 14B, and FIG. In the following, for the sake of convenience, the operation of the communication terminal 100 that receives content and the operation of the communication terminal 200 that transmits content will be described. The reception of content and the transmission of content at each communication terminal may be performed in parallel.

  FIG. 14A is a flowchart showing a first operation which is a part of the operation in the communication terminal 200 according to the fourth embodiment. The first operation in communication terminal 200 is a series of operations from the reception of the SV message to the start of the content transmission process.

  First, the communication unit 210 of the communication terminal 200 receives an SV message periodically broadcast from the communication terminal 100 (S201), and a list of contents included in the received SV message is transferred to the content transmission control unit 220E. The

  The content transmission control unit 220E compares the content list stored in the communication terminal 100 included in the SV message with the content stored in the content storage unit 230A of the communication terminal 200. From the comparison result, the content transmission control unit 220E extracts the content stored in the communication terminal 200 and not held by the communication terminal 100 (S202).

  If there is no content to be transmitted to the communication terminal 100, the content transmission control unit 220E returns to waiting for the reception of the SV message (No in S203). When there is content to be transmitted to the communication terminal 100 (Yes in S203), the content transmission processing unit 220F is instructed to start the content transmission processing (S204), and the process returns to waiting for receiving the SV message.

  FIG. 14B is a flowchart illustrating a second operation that is a part of the operation in the communication terminal 200 according to the fourth embodiment. The second operation in the communication terminal 200 is a series of operations from the transmission of the content identifier to the completion of transmission of the content or the stop of transmission after the establishment of the communication session. The second operation is started with the content transmission process (S204) in the first operation as a trigger.

  First, the content transmission processing unit 220F establishes a communication session and transmits a transmission content notification including the content identifier of the content to be transmitted to the communication terminal 100 in the communication session (S205). Next, the content transmission processing unit 220F starts transmission of the content instructed by the content transmission control unit 220E to the communication terminal 100 (S206). When there are a plurality of contents to be transmitted, the content transmission processing unit 220F may transmit the contents in parallel.

  If the communication terminal 100 refuses to receive the content while transmitting the content to the communication terminal 100 (S207), the content transmission processing unit 220F stops the transmission of the content to the communication terminal 100 ( S208).

  If there is no rejection of content reception (No in S207), the content transmission processing unit 220F continues to transmit content and completes content transmission (S209). Note that the content transmission control unit 220E may return to waiting for the reception of the SV message without waiting for the completion of transmission of the content transmitted by the content transmission processing unit 220F.

  Finally, the content transmission processing unit 220F closes the communication session after the content transmission is completed and ends the content transmission processing.

  FIG. 15 is a flowchart showing the operation of the communication terminal 100 that receives content.

  After establishing a communication session with the communication terminal 200-1 and the communication terminal 200-2, the content reception control unit 120B receives a transmission content notification through the communication session (S101).

  Further, the content reception control unit 120B has a corresponding content stored in the content storage unit 130A or a corresponding communication session stored in the corresponding information storage unit 130B for the content identifier included in the received transmission content notification. (S102).

  If there is a communication session corresponding to the content identifier (Yes in S102A) or the content has been saved (Yes in S102B), the content reception control unit 120B rejects reception of the content corresponding to the received content identifier (S103). Note that the order of the conditions in S102A and S102B may be reversed. Further, in S102, when there is another communication session corresponding to the received content identifier, confirmation of whether the content has been saved may be omitted.

  When there is no communication session corresponding to the content identifier (No in S102A) and the content is not yet saved (No in S102B) (No in S102), the content reception control unit 120B sets the correspondence between the content identifier and the communication session. The information is registered in the correspondence information storage unit 130B (S103B).

  Subsequently, the content reception processing unit 120C starts to receive content corresponding to the received content identifier (S104). The content reception processing unit 120C determines whether the content can be continuously received. For example, if a content packet cannot be received within a predetermined time, it is determined that the content cannot be received continuously, and the correspondence between the content and the communication session is saved without saving the content. Delete from the unit 130B, close the communication session, and end the process.

  Further, the content reception processing unit 120C determines whether the content reception is completed, and when the content reception is completed, stores the received content in the content storage unit 130A (S105). Subsequently, the content reception processing unit 120C registers the content storage status in the correspondence information of the correspondence information storage unit 130B (S106), and deletes the information of the communication session that received the content from the correspondence information.

  Next, the content reception processing unit 120C deletes the correspondence information between the content identifier of the content that has been received and the communication session from the correspondence information storage unit 130B. Finally, the communication unit 110 closes the communication session that received the content and ends the process.

  As described above, according to the fourth embodiment, overlapping transmission / reception of contents can be prevented, and waste of network resources between terminals can be reduced.

  FIG. 16 is a sequence diagram illustrating effects in the communication terminal according to the fourth embodiment. The communication terminal 200-1 and the communication terminal 200-2 that have received the SV message from the communication terminal 100 each establish a communication session with the communication terminal 100, and notify the transmission content notification of the content in the communication terminal 100. Send to.

  When the communication terminal 100 receives the transmission content notification including the content identifier of the communication terminal 200-1, the communication information established between the communication terminal 200-1 and the corresponding content identifier in the correspondence information storage unit 130B of the communication terminal 100 And wait for content reception.

  Subsequently, when the communication terminal 100 receives the transmission content notification including the content identifier of the communication terminal 200-2, the communication terminal 100 refers to the correspondence information between the content identifier and the communication session. The communication terminal 100 discovers the existence of a content communication session that overlaps with the communication terminal 200-2, and notifies the communication terminal 200-2 of a content reception rejection notification.

  The communication terminal 200-2 stops the transmission of the content. As a result, duplicate transmission / reception of contents is prevented, and waste of network resources between terminals is reduced.

[Fifth Embodiment]
A communication terminal according to the fifth embodiment of the present invention will be described with reference to FIGS. A communication terminal according to the fifth embodiment of the present invention is a communication terminal to which an epidemic method using inter-terminal communication is applied. The communication terminal 300 can communicate with the communication terminal 400 in an autonomous and distributed manner, and can establish a plurality of different communication sessions (communication session AB and communication session AB2) with the communication terminal 400. The communication terminal according to the fifth embodiment will be described as an example of a pull type in an epidemic system based on inter-terminal communication.

  The communication terminal 300 will be described below as a communication terminal that receives content, and the communication terminal 400 as a communication terminal that transmits content.

  FIG. 18 is a block diagram showing a configuration of communication terminal 300 that receives content. Referring to FIG. 18, a communication terminal 300 according to the fifth embodiment of the present invention includes a communication unit 310, an arithmetic processing unit 320, and a storage unit 330.

  The communication unit 310 has the same function as the communication unit 110 in the fourth embodiment, and has a function of communicating with the communication terminal 400.

  The arithmetic processing unit 320 includes an SV message receiving unit 320D, a content reception control unit 320B, a content reception processing unit 320C, and a request processing unit 320G. The content reception control unit 320B and the content reception processing unit 320C have the same configurations as the content reception control unit 120B and the content reception processing unit 120C in the fourth embodiment, respectively.

  The SV message receiving unit 320D transfers the content list included in the received SV message to the request processing unit 320G.

  The request processing unit 320G has a function of transmitting a request message for requesting content to the communication terminal 400. The request processing unit 320G compares the content list stored in the communication terminal 400 included in the SV message with the content stored in the content storage unit 330A of the terminal itself. Subsequently, the request processing unit 320G extracts content held by the communication terminal 400 but not held by the own terminal.

  Further, the request processing unit 320G excludes the content whose corresponding content identifier is stored in the corresponding information storage unit 330B from the extracted content, and extracts the content requested from the communication terminal 400.

  If the requested content does not exist, the request processing unit 320G again waits for the transfer of the content list included in the SV message from the SV message receiving unit 320D.

  On the other hand, when the requested content exists, a request message for requesting the content is transmitted to the communication terminal 400.

  When there are a plurality of requested contents, the request processing unit 320G may transmit a plurality of requested contents in one request message, or may transmit a request message for each requested content.

  In addition, after transmitting the request message to the communication terminal 400, the request processing unit 320G determines that the transmitted request message has not arrived when the transmission content notification including the content identifier is not received for a predetermined time or longer, and communicates the request message. You may retransmit to the terminal 400. Further, if the transmission content notification is not received even after a predetermined number of retransmissions, the process may be terminated.

  Alternatively, an item indicating “after request / before reception start” is provided in the correspondence information storage unit 330B, and the request processing unit 320G also refers to this when creating a request message, and selects the content after the request / before reception start. May be excluded from the request. At this time, the request processing unit 320G may register “after request / before reception start” in the correspondence information storage unit 330B with respect to the content requested after transmitting the request message. Furthermore, the content reception control unit 320B may delete information indicating “after request / before reception start” corresponding to the content from the correspondence information storage unit 330B when receiving the transmission content notification.

  The storage unit 330 includes a content storage unit 330A and a correspondence information storage unit 330B, and has the same functions as the content storage unit 130A and the correspondence information storage unit 130B in the fourth embodiment, respectively.

  The transmission content notification received by the communication unit 310 is transferred to the content reception control unit 320B, the content is transferred to the content transmission processing unit 320C, and the SV message is transferred to the request message processing unit 320G.

  FIG. 17 is a block diagram showing a configuration of communication terminal 400 that transmits content. Referring to FIG. 17, a communication terminal 400 according to the fifth embodiment of the present invention includes a communication unit 410, an arithmetic processing unit 420, and a storage unit 430.

  The communication unit 410 has a function of communicating with the communication terminal 300.

  The arithmetic processing unit 420 includes an SV message transmission unit 420A, a content transmission control unit 420E, and a content transmission processing unit 420F.

  The SV message transmission unit 420A has the same function as that of the SV message transmission unit 120A of the fourth embodiment, and has a function of creating a list of contents stored by the content storage unit 430A as an SV message. The communication unit 410 is instructed to publicize.

  The content transmission control unit 420E has a function of controlling transmission of the requested content. The difference between the content transmission control unit 420E and the content transmission control unit 220E of the fourth embodiment is a difference between content transmission control based on reception of a request message or content transmission control based on reception of an SV message, and is different in main functions. There is no.

  When a request message requesting content is received from the communication terminal 300, the request message is transferred to the content transmission control unit 420E, and the content transmission control unit 420E transmits the content requested by the communication terminal 300 included in the request message. The content is extracted, and the content transmission processing unit 420F is instructed to transmit the content.

  The content transmission processing unit 420F has the same function as the content transmission processing unit 220F of the fourth embodiment, and performs content transmission processing instructed by the content transmission control unit 420E. The content transmission processing unit 420F reads the content instructed from the content transmission control unit 420E from the content storage unit 430A, and transmits the content to the communication terminal 300 following the transmission content notification of the content.

  Here, when there are a plurality of requested contents, the content transmission processing unit 420F performs each content transmission process in parallel. Note that the content transmission control unit 420E may return to waiting for reception of a request message without waiting for the content transmission processing of the content transmission processing unit 420F to end. The content transmission control unit 420E and the content transmission processing unit 420F may operate in parallel.

  Next, the operation of the communication terminal according to the fifth embodiment will be described with reference to FIGS. 19A, 19B, 20A, and 20B. In the following, for the sake of convenience, the operation of the communication terminal 300 that receives content and the operation of the communication terminal 400 that transmits content will be described. The reception of content and the transmission of content at each communication terminal may operate in parallel.

  FIG. 20A is a flowchart showing a first operation which is a part of the operation in the communication terminal 300 according to the fifth embodiment of the present invention. The first operation is a series of operations from the reception of the SV message to the transmission of the request message.

  First, the communication unit 310 of the communication terminal 300 receives the SV message (S301), and the SV message is transferred to the SV message receiving unit 320D. The SV message receiving unit 320D transfers the content list included in the SV message to the request processing unit 320G. The request processing unit 320G compares the content list held by the communication terminal 400 included in the SV message with the content stored in the own terminal, and stores the content held by the communication terminal 400 but not held by the own terminal. Extract.

  Further, the request processing unit 320G excludes the content whose corresponding content identifier is stored in the corresponding information storage unit 330B from the extracted content, and extracts the content requested from the communication terminal 400 (S302). Subsequently, the request processing unit 320G transmits a request message for requesting the content to the communication terminal 400 (S303).

  In addition, an item indicating “after request / before reception start” is provided in the correspondence information storage unit 330B, and this is also referred to when creating a request message, and contents after the request / before reception start are excluded from the request. May be.

  If the communication terminal 300 does not receive the transmission content notification including the content identifier after a predetermined time after transmitting the request message to the communication terminal 400, the request processing unit 320G may retransmit the request message to the communication terminal 400. Good. Further, if the transmission content notification is not received even after a predetermined number of retransmissions, the process may be terminated.

  FIG. 20B is a flowchart showing a second operation which is a part of the operation in communication terminal 300 according to the fifth embodiment of the present invention. The second operation starts every time a transmission content notification including a content identifier is received.

  When the communication terminal 300 receives the transmission content notification including the content identifier from the communication terminal 400 (S304), the content reception control unit 320B determines that the content corresponding to the content identifier included in the received transmission content notification is the content storage unit 330A. Or the corresponding communication session is stored in the correspondence information storage unit 330B (S305).

  When there is a communication session corresponding to the content identifier (Yes in S305A) or content has been saved (Yes in S305B), the content reception control unit 320B rejects reception of the content corresponding to the received content identifier. (S306). Note that the order of the determination of the conditions in S305A and S305B may be reversed. Further, in S305, when there is another communication session corresponding to the content identifier, confirmation of whether the content has been saved may be omitted.

  When the communication session corresponding to the content identifier does not exist (No in S305A) and the content has not been saved (No in S305B), the content reception control unit 320B displays the correspondence information between the content identifier and the communication session as the correspondence information storage unit It is registered in 330B (S307).

  Subsequently, the content reception processing unit 320C starts receiving the content (S308). The content reception processing unit 320C determines whether content can be continuously received. For example, when a content packet cannot be received within a predetermined time, the content reception processing unit 320C determines that the content cannot be received continuously, and stores the content and the communication session without storing the content. Is deleted from the correspondence information storage unit 330B, the communication session is closed, and the process is terminated.

  Further, the content reception processing unit 320C determines whether or not the content has been received. When the content reception is completed, the content reception processing unit 320C stores the received content in the content storage unit 330A (S309).

  Next, the content reception processing unit 320C registers the storage status of the content in the correspondence information of the correspondence information storage unit 330B (S310), and displays the correspondence information between the content identifier of the content that has been received and the communication session. Delete from the storage unit 330B. The communication unit 310 closes the communication session that received the content and ends the process.

  FIG. 19A is a flowchart showing a first operation which is a part of the operation in the communication terminal 400 according to the fifth embodiment. The first operation in communication terminal 400 is a series of operations from the reception of a request message to the start of content transmission processing.

  First, the SV message transmission unit 420A of the communication terminal 400 periodically publishes a list of contents stored in the content storage unit 430A of the communication terminal 400 to surrounding communication terminals as an SV message. The communication terminal 300 that has received the SV message transmits a request message to the communication terminal 400 in order to request content that the terminal itself does not hold.

  When the communication unit 410 of the communication terminal 400 receives a request message requesting content (S401), the request message is transferred to the content transmission control unit 420E. The content transmission control unit 420E extracts the requested content from the request message (S402). Further, the content transmission control unit 420E instructs the content transmission processing unit 420F to start the content transmission processing (S403), and returns to waiting for reception of the request message.

  FIG. 19B is a flowchart illustrating a second operation that is a part of the operation of the communication terminal 400 according to the fifth embodiment. The second operation in the communication terminal 400 is a series of operations from the establishment of the communication session to the completion of transmission of the requested content or the suspension of transmission of the requested content. The second operation is started with the content transmission process (S403) in the first operation as a trigger.

  The content transmission processing unit 420F establishes a communication session with the communication terminal 300 and transmits a transmission content notification including the content identifier of the requested content to the communication terminal 300 (S404). Subsequently, the content transmission processing unit 420F starts transmission of the content requested from the communication terminal 300 (S405). When there are a plurality of contents to be transmitted, the content transmission processing unit 420F may perform each content transmission in parallel.

  If the communication terminal 300 refuses to receive the content during the transmission of the content to the communication terminal 300 (S406), the content transmission processing unit 420F stops the transmission of the content to the communication terminal 300 (S407). .

  If there is no rejection of content reception (No in S406), the content transmission processing unit 420F continues to transmit the requested content and completes the transmission of all the content (S408).

  Finally, the content transmission processing unit 420F closes and ends the communication session after the content transmission is completed.

  As described above, the communication terminal according to the fifth embodiment can prevent duplicate transmission / reception of contents and reduce waste of network resources between terminals.

  FIG. 21 is a sequence diagram illustrating effects in the communication terminal according to the fifth embodiment. As described with reference to FIG. 26, when receiving the SV message from the communication terminal 400, the communication terminal 300 may transmit the request message to the communication terminal 400 in duplicate in preparation for dropping the request message. At this time, the content transmitted by the communication terminal 400 in response to the second request message overlaps with the content transmitted in response to the first request message.

  As illustrated in FIG. 21, when the communication terminal 300 according to the fifth embodiment receives the transmission content notification including the second content identifier, the communication terminal 300 refers to the correspondence information in the correspondence information storage unit 330B and receives the preceding content. It is identified that duplicate content is received, and a content reception refusal notification is notified to the communication terminal 400. The communication terminal 400 stops the content transmission. As a result, duplicate transmission / reception of contents is prevented, and waste of network resources between terminals is reduced.

[Sixth Embodiment]
The communication terminal according to the sixth embodiment of the present invention is a communication terminal having a content receiving function and a content transmitting function, and further having an epidemic push type and pull type function. A communication terminal according to the sixth embodiment of the present invention will be described with reference to the drawings.

  FIG. 22 is a block diagram illustrating a configuration of a communication terminal 500 according to the sixth embodiment. Hereinafter, in description of the communication terminal 500 of 6th Embodiment, the same code | symbol is attached | subjected to the structure similar to the communication terminal 300 and communication terminal 400 of 5th Embodiment, and detailed description is abbreviate | omitted.

  The communication terminal 500 of the sixth embodiment is different from the communication terminal 300 of the fifth embodiment in the configuration of the arithmetic processing unit. The arithmetic processing unit 520 of the communication terminal 500 includes an SV message transmission unit 420A, a content transmission control unit 520E, and a content transmission processing unit 420F based on the arithmetic processing unit 320. The SV message transmission unit 420A and the content transmission processing unit 420F of the arithmetic processing unit 520 have the same functions as the SV message 420A and the content transmission processing unit 420F of the communication terminal 400, respectively.

  The content transmission control unit 520E has a function of controlling transmission of content using an SV message as a trigger, and a function of controlling transmission of content in response to reception of a request message. Specifically, the content transmission control unit 520E receives a list of content held by another terminal included in the SV message from the SV message reception unit 320D and compares it with the content stored in the content storage unit 330A. Subsequently, the content transmission control unit 520E extracts the content held by the own terminal and not held by the other terminal as the content to be transmitted to the other terminal. The content transmission control unit 520E instructs the content transmission processing unit 420F to start transmission processing of the content, and returns to waiting for reception of the SV message.

  On the other hand, when a request message requesting content is received from another terminal, the request message is transferred to the content transmission control unit 520E, and the content transmission control unit 520E receives the content requested by the other terminal included in the request message. And instruct the content transmission processing unit 420F to start the content transmission processing.

  Next, the operation | movement of the communication between terminals using the communication terminal 500 which concerns on 6th Embodiment is demonstrated using FIG. FIG. 23 is a sequence diagram of inter-terminal communication using two communication terminals 500 according to the sixth embodiment. For convenience of explanation, it is assumed that the communication terminal 500-1 holds the content A and the communication terminal 500-2 holds the content X.

  First, the communication terminal 500-2 broadcasts an SV message X including a list of contents X to be held to peripheral terminals. The communication terminal 500-1 that has received the SV message X of the communication terminal 500-2 refers to the list of contents included in the received SV message and requests a request message after establishing a communication session in order to request content that the terminal itself does not hold. X is transmitted to the communication terminal 500-2.

  Furthermore, the communication terminal 500-1 refers to the received SV message X, and transmits a content A held by itself and not held by the communication terminal 500-2 to the communication terminal 500-2. After the session is established, a transmission content notification including the content identifier is transmitted. The transmission content notification includes the content identifier ID_A and is transmitted to the communication terminal 500-2. Thereafter, the communication terminal 500-1 transmits the content A to the communication terminal 500-2.

  On the other hand, the communication terminal 500-2 that has received the request message X from the communication terminal 500-1 transmits a transmission content notification including the content identifier ID_X to the terminal 500-1 prior to transmission of the content X.

  Thereafter, the communication terminal 500-2 starts transmitting the content X to the communication terminal 500-1.

  According to the communication terminal of the sixth embodiment, the communication terminal 500-1 refers to the content list included in the SV message transmitted by the communication terminal 500-2, and the communication terminal 500-1 holds the communication terminal 500-. 2 has a function of transmitting content not held by the communication terminal 500-2. In addition, the communication terminal 500-1 refers to the content list included in the SV message transmitted by the communication terminal 500-2, and the communication terminal 500-1 does not hold the content held by the communication terminal 500-2. 500-2 is provided.

  The communication terminal 500 according to the sixth embodiment has a content transmission / reception function, so that the communication terminal 500-2 does not wait for an SV message to be transmitted from the communication terminal 500-1. The content held and not held by the communication terminal 500-2 can be received. Thereby, the sharing of information by communication between terminals can be advanced quickly.

  Further, in the inter-terminal communication using the communication terminal according to the sixth embodiment, when communication terminals transmit and receive SV messages to share content by transmitting a transmission content notification including a content identifier prior to content transmission. Duplication of content transmission / reception can be prevented.

The operation of communication between terminals where content duplication occurs due to transmission / reception of SV messages will be described below. It is assumed that the communication terminal T holds content A that the communication terminal S does not hold.
(1) The communication terminal S transmits the SV message 1 including the content list.
(2) The communication terminal T starts a process of transmitting the content A of its own terminal to the communication terminal S in response to the SV message 1.
(3) While the content A is being transmitted, the communication terminal T transmits the SV message 2.
(4) The communication terminal S transmits a request message for requesting the content A in response to the SV message 2 to the communication terminal T (because the communication terminal S is in the process of receiving the content A but cannot grasp until the reception of the content A is completed).
(5) The communication terminal T transmits the content A in response to the request message from the communication terminal S.

  As described above, the transmission / reception of the SV message in the inter-terminal communication causes the content to be duplicated and wastes the network resources for the inter-terminal communication.

  According to the communication terminal of the sixth embodiment, by transmitting the content identifier prior to the transmission of the content, the communication terminal that has received the content identifier can know the presence of the content being received, and duplicate content transmission Can be prevented.

(Hardware configuration)
FIG. 24 is a diagram illustrating a hardware configuration in which the communication terminal according to the first to sixth embodiments of the present invention is realized by a computer apparatus.

  As shown in FIG. 24, the communication terminal includes a CPU (Central Processing Unit) 511, a communication unit 512, a memory 513, and a storage device 514 such as a hard disk for storing programs and data. The communication terminal is connected to the input device 515 and the output device 516 via the system bus 517.

  The CPU 511 operates the operating system to control the communication terminals of the first to sixth embodiments. Further, the CPU 511 reads a program and data from the recording medium mounted on the drive device to the memory 513, for example.

  Further, the CPU 511 has, for example, each function of the arithmetic processing unit of the communication terminal in each embodiment, and executes processing of various functions based on a program.

  The storage device 514 is, for example, an optical disk, a flexible disk, a magnetic optical disk, an external hard disk, or a semiconductor memory. A part of the storage medium of the storage device 514 is a nonvolatile storage device, and stores a program therein. The program is connected to a communication network. It may be downloaded from an external computer (not shown).

  The input device 515 is realized by, for example, a mouse, a keyboard, or a touch panel, and is used for an input operation. The output device 516 is used for outputting and confirming information processed by the CPU 511.

  While the present invention has been described with reference to the embodiments (and examples), the present invention is not limited to the above embodiments (and examples). Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.

  Part or all of the above-described embodiments can be described as in the following supplementary notes, but is not limited thereto.

  (Supplementary Note 1) In a communication session of communication between terminals that transmits and receives a content identifier corresponding to content, a content reception processing unit that receives the content identifier before receiving the content, and other content corresponding to the received content identifier A communication terminal comprising: a content reception control unit that rejects reception of the content corresponding to the received content identifier when a communication session exists.

  (Additional remark 2) The said content reception control part is a communication terminal of Additional remark 1 which receives the said content corresponding to the received said content identifier, when the said other communication session does not exist.

  (Supplementary Note 3) A correspondence information storage unit that stores correspondence information between the received content identifier and its communication session, and the content reception control unit refers to the correspondence information of the correspondence information storage unit, The communication terminal according to appendix 1 or 2, wherein it is determined whether another communication session related to the received content identifier exists.

  (Supplementary Note 4) The content reception processing unit deletes the information of the communication session that has received the content from the correspondence information of the correspondence information storage unit when the reception of the content is completed or the reception is stopped halfway. 3. The communication terminal according to 3.

  (Supplementary Note 5) When the content storage unit stores the content in its own terminal, and the content reception control unit stores the content corresponding to the received content identifier in the content storage unit, the received content identifier 5. The communication terminal according to any one of appendix 1 to appendix 4, wherein reception of content corresponding to is rejected.

  (Supplementary note 6) Any one of Supplementary note 1 to Supplementary note 4, further comprising a content storage unit that stores content in its own terminal, and an SV message transmission unit that transmits a list of content stored in the content storage unit to another communication terminal The communication terminal according to claim 1.

  (Supplementary note 7) The content list included in the SV message transmitted from the other communication terminal is compared with the content stored in the content storage unit of the own terminal, and the content held by the other communication terminal not held by the own terminal The communication terminal according to any one of appendix 1 to appendix 6, further comprising: a request message processing unit that transmits a request message to request transmission.

  (Supplementary note 8) The communication terminal according to supplementary note 7, wherein the request message processing unit excludes the content corresponding to the content identifier registered in the correspondence information of the correspondence information storage unit from the content requested to be transmitted.

  (Supplementary Note 9) A content transmission processing unit that transmits the content stored in the content storage unit to another communication terminal, the content transmission processing unit corresponding to the content to be transmitted before transmission of the stored content The communication terminal according to any one of appendix 1 to appendix 4, wherein the content identifier is transmitted to another communication terminal.

  (Additional remark 10) The communication terminal of Additional remark 9 provided with the content transmission control part which instruct | indicates the said content transmission process part and establishes the communication session of the terminal communication with said other communication terminal.

  (Supplementary Note 11) A content reception processing unit that receives the content identifier before receiving the content in a communication session of terminal-to-terminal communication that transmits and receives a content identifier corresponding to the content, and other content corresponding to the received content identifier A communication terminal comprising: a content reception control unit that rejects reception of the content corresponding to the received content identifier when a communication session exists.

  (Supplementary Note 12) When an SV message is received from another communication terminal, a list of contents held in the other communication terminal included in the SV message and contents stored in the content storage unit of the own terminal As a result of comparison between the content transmission control unit and the content transmission control unit, the content stored in the local terminal is not stored in the other communication terminal, and is extracted from the content storage unit as the content to be transmitted to the other communication terminal The communication terminal according to appendices 1 to 4, provided with a content transmission processing unit.

  (Additional remark 13) The said content transmission process part is a communication terminal which receives the reception refusal notification transmitted from the other communication terminal, and stops transmission of the content from the own terminal to the said other communication terminal.

  (Supplementary note 14) In a communication session of communication between terminals that transmits and receives a content identifier corresponding to content, when the content identifier is received before the content is received, and there is another communication session corresponding to the received content identifier A communication control method for rejecting reception of the content corresponding to the received content identifier.

  (Supplementary Note 15) In a communication session of communication between terminals that transmits and receives a content identifier corresponding to content, the computer receives the content identifier before receiving the content, and there is another communication session for the received content identifier If so, a program for causing the reception of the content corresponding to the received content identifier to be rejected.

DESCRIPTION OF SYMBOLS 10 Communication terminal 11 Content reception process part 12 Content reception control part 20-1, 20-2 Communication terminal 21 Content transmission process part 22 Content transmission control part 23 Content storage part 30 Communication terminal 32 Content reception control part 33 Corresponding information storage part 40 Communication terminal 41 Content reception processing unit 42 Content reception control unit 43 Corresponding information storage unit 44 Content storage unit 100 Communication terminal 110 Communication unit 120 Arithmetic processing unit 120A SV message transmission unit 120B Content reception control unit 120C Content reception processing unit 130 Storage unit 130A Content storage unit 130B Corresponding information storage unit 200-1, 200-2 Communication terminal 210 Communication unit 220 Operation processing unit 220D SV message reception unit 220E Content transmission control unit 220F Content transmission Processing unit 230 Storage unit 230A Content storage unit 300 Communication terminal 310 Communication unit 320 Arithmetic processing unit 320B Content reception control unit 320C Content reception processing unit 320D SV message reception unit 320G Request processing unit 330 Storage unit 330A Content storage unit 330B Corresponding information storage unit 400 communication terminal 410 communication unit 420 arithmetic processing unit 420A SV message transmission unit 420E content transmission control unit 420F content transmission processing unit 430 storage unit 430A content storage unit 500 communication terminal 511 CPU
512 Communication Unit 513 Memory 514 Storage Device 515 Input Device 516 Output Device 517 System Bus 520 Arithmetic Processing Unit 520E Content Transmission Control Unit

Claims (10)

A content reception processing unit that receives the content identifier before receiving the content in a communication session of communication between terminals that transmits and receives a content identifier corresponding to the content;
A content reception control unit that rejects reception of the content corresponding to the received content identifier when there is another communication session corresponding to the received content identifier;
A communication terminal comprising:   The communication terminal according to claim 1, wherein the content reception control unit receives the content corresponding to the received content identifier when the other communication session does not exist. A correspondence information storage unit for storing correspondence information between the received content identifier and its communication session,
The communication terminal according to claim 1, wherein the content reception control unit determines whether there is another communication session related to the received content identifier by referring to the correspondence information of the correspondence information storage unit.   The content reception processing unit deletes information on a communication session that has received the content from the correspondence information in the correspondence information storage unit when reception of the content is completed or reception is stopped in the middle. Communication terminal. It has a content storage unit that stores content on its own terminal,
The content reception control unit rejects reception of the content corresponding to the received content identifier when the content corresponding to the received content identifier is stored in the content storage unit. The communication terminal according to any one of the above. It has a content storage unit that stores content on its own terminal,
The communication terminal according to any one of claims 1 to 4, further comprising an SV message transmission unit that transmits a list of contents stored in the content storage unit to another communication terminal. The content list included in the SV message transmitted from the other communication terminal is compared with the content stored in the content storage unit of the own terminal, and the transmission request is made for the content held by the other communication terminal without being held by the own terminal. A request message processing unit for sending a request message,
The communication terminal according to any one of claims 1 to 6, comprising: The request message processing unit
The communication terminal according to claim 7, wherein content corresponding to a content identifier registered in correspondence information in the correspondence information storage unit is excluded from the content requested to be transmitted. In a communication session of communication between terminals that transmits and receives a content identifier corresponding to the content, the content identifier is received before receiving the content,
A communication control method for rejecting reception of the content corresponding to the received content identifier when there is another communication session corresponding to the received content identifier. On the computer,
In a communication session for communication between terminals that transmits and receives a content identifier corresponding to content, the content identifier is received prior to reception of the content, and when there is another communication session for the received content identifier, the received content Refusing to receive the content corresponding to the identifier;
A program to make things happen.

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