JPWO2011114584A1 - Information sharing method and communication terminal - Google Patents

Abstract

When transmitting the notification message to the communication terminal (100-2), the priority control unit (132) is at least one piece of information among the possessed information common to the communication terminal (100-1) and the communication terminal (100-2). When the exchange detection unit (131) receives the notification message from the communication terminal (100-2), the notification message and the information held by the communication terminal (100-1) are changed. If there is common information, the information exchange unit (111) sends the message changed by the priority control unit (132) to the communication terminal (100-2). If there is no common information, the notification message is transmitted to the communication terminal (100-2) without being changed, and the exchange detection unit (131) needs to transmit the notification message. If it is determined that that sends a notification message.

Description

  The present invention relates to an information sharing method and a communication terminal for sharing information.

  In recent years, the Internet has been rapidly spreading, and wireless communication technology has been rapidly developed. Along with the spread of mobile communication terminals such as mobile phones and automobiles having a wireless communication function that can be connected to the Internet, an ad hoc network that does not require a communication infrastructure in which the mobile communication terminals form a network between the terminals. The sharing service of information content (collectively referring to image, music, video, text, message position information, etc.) is promising. The shared service is expected as a means of information transmission in urban areas and disaster areas.

  However, this ad hoc network is based on wireless communication. Therefore, unlike the Internet configured by a wired network, communication performance (communication bandwidth) is greatly limited by the surrounding environment of mobile communication terminals, obstacles, radio wave interference, and the like. In addition, due to the movement of the mobile communication terminal, the communication topology of the formed ad hoc network is changed, and disconnection of the route frequently occurs. Therefore, stable communication like a wired network cannot be expected.

  In order to share information with other communication terminals in a communication environment in which such communication performance (communication band) is limited and there is no guarantee of a communication path, each other can communicate with other communication terminals. It is effective to exchange information. As one of the methods, there has been proposed a method of synchronizing owned information by exchanging information with each other when mobile communication terminals come into contact with each other by movement (see Non-Patent Document 1, for example). .

  Non-Patent Document 1 proposes an epidemic algorithm that synchronizes retained information among all mobile communication terminals. The epidemic algorithm is characterized in that information synchronization is performed based on a summary vector (hereinafter referred to as SV) that is a message that summarizes information held by a mobile communication terminal and notifies other mobile communication terminals.

  In the epidemic algorithm, when a mobile communication terminal in the network detects another mobile communication terminal, it exchanges SVs with each other and grasps the contents of the SV of the other mobile communication terminal. Then, based on the received SV, the content that the mobile communication terminal does not have is investigated and an attempt is made to acquire the content.

  FIG. 1 is a diagram illustrating an example of a general SV exchange between mobile communication terminals.

  As shown in FIG. 1, for example, between terminals T1 and T2 which are mobile communication terminals, terminals T1 and T2 which are in contact with each other exchange SV 1000 with each other. Then, the terminal T2 confirms the difference content by comparing the SV received from the terminal T1 with the SV of the terminal T2 to determine whether there is content that the terminal T2 does not have.

  In the example illustrated in FIG. 1, since the terminal T2 does not have the content B, the content T acquisition request is transmitted to the terminal T1, and the content B that was not held is acquired. This operation is repeated by all terminals in the network to synchronize the information held between the terminals.

  Further, as described above, the epidemic algorithm recognizes contents not owned by the terminal itself by comparing the contents held by the individual terminals using SV, and exchanges the contents. The SV replaces the information indicated by the SV with information in the network (terminal position coordinates and owned content information), recognizes information existing on the network, and sends a content acquisition request to the terminal in the network. Is also applicable.

  However, since the epidemic algorithm is a technique for exchanging information that is not held one after another between terminals, the bandwidth load is very high.

  Therefore, SV transmission intervals and exchange methods have been determined for the purpose of reducing the bandwidth load (see, for example, Non-Patent Document 2).

  Non-Patent Document 2 describes a basic epidemic algorithm exchange method. The epidemic algorithm defines an epidemic round (or cycle) as an SV exchange interval, and information exchange is performed at each interval.

  The information exchange operation includes a unidirectional exchange such as a Push type in which only the own terminal transmits information to the adjacent terminal, and a Pull type in which information is collected from the adjacent terminal only to the own terminal, and an event is detected for the adjacent terminal ( There is a Push-Pull type two-way exchange in which the Push type and Pull type are exchanged simultaneously when new holding information is recognized.

  As described above, the epidemic algorithm is characterized in that information is propagated one hop at every information exchange interval by exchanging information with an adjacent terminal at the time of detecting a transmission event periodically or spontaneously.

  Here, considering the environment in which the epidemic algorithm is used, since the communication topology changes frequently, important information and the like need to be quickly propagated to adjacent terminals.

  However, the epidemic algorithm basically defines an information exchange interval.

  FIG. 2 is a diagram illustrating an example of a state of information propagation using the epidemic algorithm.

  As shown in FIG. 2, the content received by the terminal Ta from the terminal T can be received by the terminal Tb by the SV transmitted from the terminal Ta to the terminal Tb. However, the content propagation to the terminal Tc is not performed until the regular transmission time of the SV of the terminal Tb and the terminal Tc.

  Thus, since information is propagated one hop at each exchange interval, information cannot be quickly transmitted to the surroundings. Therefore, means other than the Epidemic algorithm must be used for distributing emergency information at a disaster site or the like.

  In order to solve this problem, it is necessary to enable the rapid transmission of information arbitrarily to the epidemic algorithm.

A. Vahdat, D. Becker, “Epidemic Routing for Partially-Connected Ad Hoc Networks,” Tech. Report CS-200006, Duke University, Apr. 2000. M. Akdere, et al., “A Comparison of Epidemic Algorithms in Wireless Sensor Networks,” Computer Communications, vol.29, 2006.

  However, the above-described technique has a problem in that after transmitting information from a communication terminal to a communication terminal adjacent to the communication terminal, the communication terminal that has received the information cannot quickly transmit the information. The reason is that each communication terminal transmits information according to a regular transmission interval.

  The objective of this invention is providing the information sharing method and communication terminal which solve the subject mentioned above.

The information sharing method of the present invention includes:
An information sharing method for sharing information held by each of a plurality of communication terminals within a communicable range by radio,
When the communication terminal transmits to the other communication terminal a notification message for notifying information held by the communication terminal to another communication terminal that is a communication terminal other than the communication terminal among the plurality of communication terminals. Investigation processing for investigating whether there is information common to the information held by the communication terminal and the information held by the other communication terminal;
When there is the common information as a result of the investigation, the communication terminal selects at least one information from the common information, and does not notify the selected communication information to the other communication terminal. Change processing for transmitting the changed notification message to the other communication terminal,
When the communication terminal does not have the common information as a result of the investigation, a process of transmitting the notification message to the other communication terminal without changing the notification message;
Whether the communication terminal needs to transmit the notification message based on the received notification message and information held by the communication terminal when the communication message is received by the other communication terminal. The process of determining
When it is determined that the notification message needs to be transmitted, the notification message is transmitted.

In addition, the information sharing method of the present invention includes:
An information sharing method for sharing information held by each of a plurality of communication terminals within a communicable range by radio,
After the communication terminal transmits information held by the communication terminal to another communication terminal that is a communication terminal other than the communication terminal among the plurality of communication terminals, the information held by the communication terminal and the other communication Investigation processing to investigate whether there is information common to the information held by the terminal,
If the communication terminal has the common information as a result of the investigation, the communication terminal selects at least one information from the common information and does not notify the other communication terminal of the selected information. Change notification message for notifying the information held by the terminal to the other communication terminal, change processing to send the changed notification message to the other communication terminal,
When the communication terminal does not have the common information as a result of the investigation, a process of transmitting the notification message to the other communication terminal without changing the notification message;
Whether the communication terminal needs to transmit the notification message based on the received notification message and information held by the communication terminal when the communication message is received by the other communication terminal. The process of determining
When it is determined that the notification message needs to be transmitted, the notification message is transmitted.

The communication terminal of the present invention
A communication terminal having a wireless communication function,
When transmitting to the other communication terminal a notification message for notifying the information held by the communication terminal to other communication terminals within a range communicable with the communication terminal, the information held by the communication terminal Investigating whether there is information common to the information held by the other communication terminal, and if there is the common information as a result of the investigation, select at least one information from the common information, A priority control unit that changes the notification message so as not to notify the selected information to the other communication terminal;
When the notification message transmitted by the other communication terminal is received, the exchange detection for determining whether the notification message needs to be transmitted based on the received notification message and information held by the communication terminal. And
As a result of the investigation by the priority control unit, when there is the common information, the message changed by the priority control unit is transmitted to the other communication terminal, and when there is no common information, the notification message is not changed. And an information exchange unit for transmitting the notification message when the exchange detection unit determines that the notification message needs to be transmitted.

The communication terminal of the present invention
A communication terminal having a wireless communication function,
Among the information held by the communication terminal, a request processing unit that determines whether information requested from another communication terminal within a range in which communication with the communication terminal can be performed is high-priority information;
An information exchange unit for transmitting the requested information to the other communication terminal;
If the request processing unit determines that the requested information is high-priority information, the information exchange unit transmits the requested information to the other communication terminal, and then the communication terminal holds the information. Investigate whether there is information common to the information and the information held by the other communication terminal, and if there is the common information as a result of the investigation, select at least one of the common information And a priority control unit that changes the notification message for notifying other communication terminals within a range communicable with the communication terminal so that the selected information is not notified to the other communication terminal,
When the notification message transmitted by the other communication terminal is received, the exchange detection for determining whether the notification message needs to be transmitted based on the received notification message and information held by the communication terminal. And
The information exchange unit transmits the message changed by the priority control unit to the other communication terminal when there is the common information as a result of the investigation by the priority control unit, and when there is no common information, The notification message is transmitted to the other communication terminal without being changed, and when the exchange detection unit determines that the notification message needs to be transmitted, the notification message is transmitted.

  As described above, in the present invention, information can be quickly transmitted to other communication terminals existing around the communication terminal.

It is a figure which shows an example of the mode of a general SV exchange between mobile communication terminals. It is a figure which shows an example of the mode of the propagation of the information using an epidemic algorithm. It is a figure which shows the 1st example of SV. It is a figure which shows the 2nd example of SV. It is a figure which shows 1st Embodiment of the communication terminal of this invention. It is a figure which shows an example of the ad hoc network comprised from the communication terminal shown in FIG. It is a flowchart for demonstrating the information sharing method in 1st Embodiment. It is a figure which shows the mode of the exchange of the information between three communication terminals in 1st Embodiment. It is a figure which shows 2nd Embodiment of the communication terminal of this invention. It is a flowchart for demonstrating the information sharing method in 2nd Embodiment. It is a figure which shows the mode of the exchange of the information between three communication terminals in 2nd Embodiment. It is a figure which shows the mode of the exchange of the information between three communication terminals in 2nd Embodiment.

  Embodiments of the present invention will be described below with reference to the drawings.

  First, a summary vector (SV) used in this embodiment will be described.

  The summary vector (hereinafter referred to as SV) is a notification message that includes information held by a communication terminal that is a mobile communication terminal, and the communication terminals notify each other of the held information.

  FIG. 3 is a diagram illustrating a first example of the SV.

  As shown in FIG. 3, possession information and position information are written as data in the SV 10a. Here, the SV 10a is a data inclusion type composed of a terminal ID which is identification information for identifying a communication terminal, position information indicating the position of the communication terminal, and a time existing at the position. .

  FIG. 4 is a diagram illustrating a second example of the SV.

  As shown in FIG. 4, the SV 10b may use summary information (replaced with content hash values, identifiers, and alternative information) of content held by terminals in the network. In this case, the SV 10b is converted into a hash value, for example. It becomes a hash table type including the listed information composed of the processed data.

In addition, the SV is not only periodically transmitted from the communication terminal, but when an event shown below is detected by exchanging the SV between the communication terminal and another adjacent communication terminal, the communication terminal To voluntarily transmit SV.
1. 1. When a new communication terminal is detected 2. When the own communication terminal holds information that the received SV does not have 3. When the received SV has information older than the information held by the own communication terminal. Transmission at a preset period As described above, by exchanging SVs, information held by other communication terminals can be monitored by the communication terminals.
(First embodiment)
The SV exchange in the first embodiment will be described on the assumption that, as shown in FIG. 3, data such as position information is written in the SV, the information is directly transmitted, and no content acquisition request is made.

  FIG. 5 is a diagram showing a first embodiment of a communication terminal according to the present invention.

  As shown in FIG. 5, communication terminal 100-1 that is a mobile communication terminal in the present embodiment is connected with communication terminal 100-2 that is another mobile communication terminal within a range that can communicate with communication terminal 100-1. The wireless communication function unit 110 that performs wireless communication via the wireless communication path 200, the information management unit 120 that manages information held by the communication terminal 100-1, and the exchange control unit 130 that controls information exchange are provided. It has been.

  The internal configuration of communication terminal 100-2 is also the same as the internal configuration of communication terminal 100-1 shown in FIG.

  The wireless communication function unit 110 is provided with an information exchange unit 111.

  The information exchange unit 111 receives information (SV, content acquisition request and response, content information, terminal location information) from another mobile communication terminal (for example, the communication terminal 100-2) through the wireless communication function unit 110, The communication terminal 100-1 has a function of periodically transmitting content information and SV held by the communication terminal 100-1.

  Further, the information received by the information exchange unit 111 is sent to the data storage unit 121 of the information management unit 120 and stored in the data storage unit 121.

  When the information exchange unit 111 receives an SV transmitted from another communication terminal, the received SV is stored in the data storage unit 121 via the exchange detection unit 131 of the exchange control unit 130.

  When information is transmitted from the information exchange unit 111, the information exchange unit 111 reads information to be transmitted from the data storage unit 121 in the information management unit 120, and transmits the read information.

  In addition, when an SV is transmitted from the information exchange unit 111, when an SV transmission notification is received from the exchange detection unit 131 other than the SV is periodically transmitted, or information is missing from the priority control unit 132 of the exchange control unit 130. When the received SV is received, the SV is transmitted.

  The information management unit 120 is provided with a data storage unit 121.

  The data storage unit 121 records the content and SV created by the communication terminal 100-1, the content acquired through the information exchange unit 111 and the SV received through the exchange detection unit 131, the function of storing and deleting the reception history, It has a function to manage the priority and importance of data. This priority and importance are set in advance.

  In addition, when the communication terminal 100-1 newly receives an SV, the data storage unit 121 integrates the received SV and the saved SV of the communication terminal 100-1. For example, the information in the SV of the communication terminal 100-1 is compared with the information in the SV of the communication terminal 100-1. If new information of the update date / time is in the reception SV, the information in the SV of the corresponding communication terminal 100-1 is overwritten. If there is newly obtained information, it is added and updated in the SV of the communication terminal 100-1.

  When the data storage unit 121 receives a notification of information transmission from the information exchange unit 111, the data storage unit 121 sends the corresponding information to the information exchange unit 111.

  When the data storage unit 121 receives an information acquisition notification from the priority control unit 132, the data storage unit 121 sends the corresponding information to the priority control unit 132.

  Further, the exchange control unit 130 is provided with an exchange detection unit 131 and a priority control unit 132.

  When the exchange detection unit 131 receives the SV transmitted from the communication terminal 100-2 from the information exchange unit 111 of the wireless communication function unit 110, the exchange detection unit 131 compares the received SV with the SV of the communication terminal 100-1. It is determined whether a voluntary exchange (transmission) of SV is necessary. As a result, it has a function of notifying the information exchanging unit 111 when the exchange is necessary. The determination of whether or not the SV needs to be voluntarily exchanged is necessary if the communication terminal 100-1 holds information that is not in the received SV or information that is new in update date and time. to decide. For example, when the SV of the communication terminal 100-1 holds information that is not included in the reception SV, it is determined that the SV of the communication terminal 100-1 is an SV with more information in the network. Then, the SV is exchanged with the communication terminal that has transmitted the received SV. Further, when it is detected that the information in the received SV is older than the SV of the communication terminal 100-1, it is determined that the SV of the communication terminal 100-1 is an SV including newer information. Then, in order to notify the communication terminal that has transmitted the received SV, it is determined that the SV needs to be replaced.

  When the communication terminal 100-1 holds information with high importance or high priority and wants to quickly transmit the information (whether or not priority is given to the content itself (importance or low priority) ) Is specified in advance, or is instructed by a user or an application), the communication terminal 100-1 is newly set so as to immediately start the transmission of the SV to the communication terminal 100-2 which is an adjacent terminal. Has a function of changing and creating the SV transmitted. For example, the priority control unit 132 reads, from the data storage unit 121, the history of the SV received from the adjacent terminal that wants to immediately transmit the SV, and confirms the information in the SV that is common with the information held by the priority control unit 132. Then, at least one piece of common information is selected from the SV of the current communication terminal 100-1, and a change is made. This is given to the selected information, for example, to create an SV obtained by extracting the selected information from the SV, to replace the selected information with other information such as a hash value or an identifier. Change the sequence number to make it look like old information or set a flag. Alternatively, without comparing with the SV of the adjacent terminal, the update date / time and generation date / time that are considered to have already been shared with the adjacent terminal in the SV of the communication terminal 100-1 or the time set in advance from the acquisition time The above-described processing may be performed on information. If there is no information common to the SV of the communication terminal 100-1 and the SV of the adjacent terminal, no change is made to the SV.

  After that, the priority control unit 132 sends a transmission notification and the created SV to the information exchange unit 111, and the information exchange unit 111 creates the SV created without waiting for the regular transmission of the SV or the regular transmission of the SV. To send from. As a result, the exchange detection unit 131 of the communication terminal 100-2 is caused to detect the lack of information of the communication terminal 100-1 and indirectly transmit the SV.

  FIG. 6 is a diagram illustrating an example of an ad hoc network including the communication terminal 100-1 illustrated in FIG.

  As shown in FIG. 6, an ad hoc network is constructed by connecting a plurality of communication terminals to each other via a wireless communication path.

  Hereinafter, an information sharing method (SV transmission control method) for sharing information in this embodiment will be described. Here, the description format of the SV for notifying possession information will be described by taking an example of using the data inclusion type SV 10a shown in FIG. Further, the changing method applied to the SV will be described by taking as an example the case of using a process for extracting information.

  FIG. 7 is a flowchart for explaining the information sharing method according to the first embodiment.

  FIG. 8 is a diagram showing how information is exchanged between three communication terminals in the first embodiment.

  Communication terminals 100-1 to 100-3 shown in FIG. 8 construct an ad hoc network that can communicate only with the adjacent communication terminal. And the communication terminals 100-1 to 100-3 have the content X as common information as shown in the upper part of FIG. Further, it is assumed that the communication terminal 100-1 newly acquires new content Y. At this time, when the communication terminal 100-1 recognizes that the content Y is information that should be promptly transmitted by priority information described in the content Y, an instruction from a user or an application, and the like, the communication terminal 100-1 quickly (In FIG. 8, the process is started using the priority control unit 132 to communicate to the communication terminal 100-2).

  First, in step 1, the priority control unit 132 of the communication terminal 100-1 investigates the SV reception history stored in the data storage unit 121, and the communication terminal 100- that is an adjacent terminal of the communication terminal 100-1. 2 reads information held. Then, in step 2, the possessed information common to the information retained by the current communication terminal 100-1 and the information retained by the communication terminal 100-2 is examined.

  When the priority control unit 132 discovers common information between the information held by the communication terminal 100-1 and the information held by the communication terminal 100-2, the priority control unit 132 selects and selects at least one of the common information found Based on the common information, the SV of communication terminal 100-1 is changed.

  For example, in step 3, the selected information is extracted (missed) from the SV of the communication terminal 100-1. Alternatively, the common information may be rewritten with an old sequence number or time stamp, or may be replaced with a hash value or other identifier of content. At this time, as a method for selecting possession information, if the content is selected at random or if the bandwidth load is reduced, all information other than the highly important content Y may be targeted, and the data size to be transmitted may be reduced. .

  In the information investigation method, the communication terminal 100-1 may independently determine the information to be extracted without investigating the common information with the adjacent terminal. For example, since the oldest information among the information held by the communication terminal 100-1 is considered to be already shared among many communication terminals, the oldest information may be extracted as information common to adjacent terminals. Further, instead of the oldest information, information that has passed a preset time from the information update date and time may be selected.

  Then, when the SV with missing information is created, the priority control unit 132 transmits to the information exchanging unit 111 the SV with missing information created by the priority control unit 132 at the next periodic transmission of the SV. Send notifications. Or you may notify to the information exchange part 111 so that SV with missing information may be transmitted immediately.

  When the information exchange unit 111 receives the notification of the SV transmission from the priority control unit 132, the information exchange unit 111 does not read the SV indicating the possession information of the communication terminal 100-1 to be originally transmitted from the data storage unit 121 at the time of the SV transmission. In step 4, the SV from which information received from 132 is missing is transmitted to the communication terminal 100-2, which is an adjacent terminal (lower part (A) of FIG. 8).

  When the communication terminal 100-2 receives the SV from which information is missing from the communication terminal 100-1, the communication terminal 100-1 deletes information common to the communication terminal 100-1 and the communication terminal 100-2. Since the SV is transmitted, the above-described spontaneous SV transmission event “2. When the own communication terminal holds information that the reception SV does not hold” is detected. Thereby, the communication terminal 100-2 updates the SV of the communication terminal 100-2 based on the information received from the communication terminal 100-1, and then enters a process of immediately transmitting its own SV, and transmits the SV. (FIG. 8, lower row (A)).

  When the communication terminal 100-2 transmits an SV, the communication terminal 100-1 transmits information to be transmitted by the communication terminal 100-1 that is not owned by the communication terminal 100-2 even if the communication terminal 100-1 receives the SV from the communication terminal 100-2. Since it does not have, the process which transmits SV newly is not performed.

  On the other hand, communication terminal 100-3, which is an adjacent terminal of communication terminal 100-2, newly receives content Y from communication terminal 100-2. That is, the communication terminal 100-3 can acquire the content Y transmitted by the communication terminal 100-1 via the communication terminal 100-2.

  As described above, when the communication terminal 100-1 transmits the SV including the content Y, which is new information, the SV with a lack of information is intentionally transmitted. This prompts the communication terminal 100-2, which is an adjacent terminal of the communication terminal 100-1, to transmit the SV, and promptly sends information to the communication terminal 100-3 that is two hops away from the communication terminal 100-1. It becomes possible to convey.

  As a result, the adjacent terminal cannot transfer information immediately in the existing technology, but in the present invention, the adjacent terminal can immediately transfer information, and information can be transmitted quickly. .

In the above-described example, information that is shared with the neighboring terminal is transmitted to the neighboring terminal so that the neighboring terminal can exchange information immediately. However, the information is replaced with old information or alternative information such as a hash value. It may be replaced with. For example, the time stamp indicating the newness of information or the sequence number is replaced with an older one than the current one (the past time if it is a time stamp, or a smaller value if it is a sequence number), and the SV is immediately sent to the adjacent terminal. It is possible to obtain the same effect even if the transmission of is promoted.
(Second Embodiment)
The second embodiment of the present invention will be described below.

  In the first embodiment, the SV description format is a data inclusion type that describes shared data. In the second embodiment, the SV description format as shown in FIG. Using the hash table SV10b in which the hash value is described, information is acquired using a content reception request (hereinafter referred to as REQ).

  FIG. 9 is a diagram showing a second embodiment of the communication terminal of the present invention.

  As shown in FIG. 9, the communication terminal 100a-1 which is a mobile communication terminal in the present embodiment replaces the exchange control unit 130 of the first embodiment shown in FIG. 5 with a request processing unit (REQ processing unit). The exchange control unit 130a to which 133 is added is a constituent element.

  The internal configuration of communication terminal 100a-2 is the same as the internal configuration of communication terminal 100a-1 shown in FIG.

  The request processing unit 133 monitors whether or not an acquisition request for information with high priority to be quickly shared from the adjacent terminal (in the form shown in FIG. 9, the communication terminal 100a-2) is received. It has a function of notifying the priority control unit 132a of execution of priority control.

  For example, the request processing unit 133 reads the priority of information shared by using SV and SV from the data storage unit 121 and grasps the priority of information shared by the SV. When receiving the content acquisition request from the information exchange unit 111a, the priority of the requested data is confirmed. If the priority is low, the corresponding information is transmitted to the information exchange unit 111b. reply. On the other hand, in the case of high priority information, a notification is sent to the information exchange unit 111a so as to transmit the corresponding information, and the priority control unit 132a is notified of the start of priority control. Make a quick transmission.

  The priority control unit 132a has a function equivalent to that of the priority control unit 132 of the first embodiment. In the first embodiment, the user or application has instructed to start processing, whereas the priority control unit 132a The embodiment is different in that processing is started by receiving a notification from the request processing unit 133.

  The information exchanging unit 111a has the same function as the information exchanging unit 111 of the first embodiment, but when receiving a new content acquisition request, notifies the request processing unit 133 of the acquisition request content, It is different in that it has a function of waiting for a response from the request processing unit 133 and transmitting information corresponding to the acquisition request.

  Hereinafter, an information sharing method (SV transmission control method) for sharing information in this embodiment will be described.

  FIG. 10 is a flowchart for explaining an information sharing method according to the second embodiment.

  FIG. 11 and FIG. 12 are diagrams showing how information is exchanged between three communication terminals in the second embodiment.

  The processing in steps 12 to 15 shown in FIG. 11 is the same as the processing in steps 1 to 4 described using the flowchart shown in FIG.

  The present embodiment is characterized in that step 11 which is the processing of the request processing unit 133 is performed before the processing of step 12.

  Similar to the first embodiment, communication terminals 100a-1 to 100a-3 shown in FIG. 11 can communicate only with adjacent terminals, and content X is shared by each other as shown in the upper part of FIG. Is held as information. Moreover, only the communication terminal 100a-1 has the content Y.

  The SV description format is a hash table in which the hash value of each content as shown in FIG. 4 is described, and information sharing is performed using a content acquisition request. At this time, a change point when the processing of the request processing unit 133 is added will be described in detail.

  First, the communication terminal 100a-1 transmits the summary vector SV (X, Y) of the communication terminal 100a-1 in which the hash values of the contents X and Y are described as regular transmission of the SV. Then, the communication terminal 100a-2 that has received the SV from the communication terminal 100a-1 compares the SV of the communication terminal 100a-2 with the received SV. As a result, it is recognized that the communication terminal 100a-1 holds “content Y” which is information that the communication terminal 100a-2 does not hold (middle (a) in FIG. 11).

  The communication terminal 100a-2 transmits REQ (Y), which is a request for acquiring the content Y, to the communication terminal 100a-1 in order to acquire the content Y from the communication terminal 100a-1 (lower row (a) in FIG. 11). ).

  When the information exchange unit 111a receives the content acquisition request REQ (Y) from the communication terminal 100a-2, the communication terminal 100a-1 notifies the request processing unit 133 of the content acquisition request. Then, in step 11, the request processing unit 133 determines whether the request is a request for high-priority content based on the notified contents.

  Specifically, in step 11, the request processing unit 133 reads the priority of the content registered in advance from the data storage unit 121 and reads whether the received acquisition request information should be immediately propagated. Judge based on degree. For example, information such as finding a rescuer in a stricken area is determined as information that should be propagated immediately. In addition, when the priority is evaluated as large, medium, or small, it can be considered that the information is propagated immediately with “high”.

  If it is determined in step 11 that the information should be immediately propagated to the request processing unit 133, the request processing unit 133 notifies the priority control unit 132a to perform the processing of steps 12 to 15 which is the priority control processing. .

  Then, the request processing unit 133 sends a notification to the information exchange unit 111a so as to transmit the content Y that is the target of the content acquisition request.

  Upon receiving the priority control start notification from the request processing unit 133, the priority control unit 132a investigates and finds the possessed information common to the adjacent terminals in step 12 and step 13, as in the first embodiment. In step 14, at least one piece of information is selected and changed (created SV with missing information), and notification is sent to the information exchange unit 111a to send the missing SV. . If there is no shared information to be shared, the priority control unit 132a sends a notification to the information exchange unit 111a so as to transmit the SV without changing the SV.

  On the other hand, if the request processing unit 133 determines in step 11 that the information is not to be propagated immediately, the request processing unit 133 transmits the content Y corresponding to the content acquisition request to the information exchange unit 111a. The priority control unit 132a is not notified of the priority control start.

  Regardless of whether priority control is possible or not, the information exchange unit 111a transmits the content Y, which is the corresponding content, when receiving the transmission notification of the corresponding content of the acquisition request from the request processing unit 133 (lower row (c) in FIG. 11).

  After transmitting the content Y to the communication terminal 100a-2, if the information exchange unit 111a has received a transmission notification of an SV with missing information from the priority control unit 132a, in step 15, the information exchange unit 111a receives the communication terminal 100a-2. The SV with the missing information is immediately transmitted to (Fig. 12 (upper (D)).

  When the communication terminal 100a-2 receives the content Y from the communication terminal 100a-1, since the retained information is newly added, the hash value of the content Y is added to the SV of the communication terminal 100a-2 to update the information. .

  Subsequently, when the communication terminal 100a-2 receives the SV from which the information is missing from the communication terminal 100a-1, the communication terminal 100a-2 receives the information “2. Information received by the reception SV is not held by the own communication terminal, as in the first embodiment. "If you have". As a result, the communication terminal 100a-2 recognizes that the communication terminal 100a-2 has information that the communication terminal 100a-1 does not have, and immediately transmits the SV of the newly updated communication terminal 100a-2. (The upper part of FIG. 12 (e)).

  At this time, even if the communication terminal 100a-1 receives the SV from the communication terminal 100a-2, the communication terminal 100a-1 has already transmitted the content Y and does not have the information to be sent. Does not cause.

  On the other hand, the communication terminal 100a-3, which is an adjacent terminal of the communication terminal 100a-2, is newly notified of the presence of the content Y from the communication terminal 100a-2 through the SV transmitted from the communication terminal 100a-2 (FIG. 12 upper row (e).

  When the communication terminal 100a-3 recognizes the presence of the content Y possessed by the communication terminal 100a-2, it starts processing similar to that of the communication terminal 100a-2 described above and tries to acquire the content Y (lower part of FIG. ), (Ki)).

  As described above, when the communication terminal 100a-1 receives the content Y acquisition request from the communication terminal 100a-2 and transmits the content Y as a response, the communication terminal 100a-2 further intentionally lacks information. A certain SV is transmitted. This prompts the communication terminal 100a-2, which is an adjacent terminal of the communication terminal 100a-1, to transmit SV, and promptly transmits information to the communication terminal 100a-3 that is two hops away from the communication terminal 100a-1. It becomes possible to convey.

  As a result, in the existing technology, adjacent terminals cannot transfer information immediately, whereas in the present invention, adjacent terminals can transfer information immediately, and information can be transmitted quickly. Become.

  In the above-described example, the information exchanged by the neighboring terminal is transmitted by transmitting the SV in which the information held in common with the neighboring terminal is deleted, but the neighboring terminal immediately exchanges information. However, the information may be replaced with old information. For example, a time stamp indicating the newness of information or a sequence number that is older than the current one (replaced time in the past if the time stamp is used, or a smaller value if the sequence number is used) is immediately transmitted to the adjacent terminal. It is possible to obtain the same effect even if the transmission of is promoted.

  In addition, the information sharing method performed in the first and second embodiments described above is similar to the epidemic algorithm, in which information is retained between individual communication terminals (devices) by notifying retained information between adjacent terminals. It can also be applied to a technique for performing synchronization.

  For example, periodically notify the holding information and status to the surroundings, such as database replication management, program code change management, resource discovery, ad hoc network routing and routing information transmission control, which is the original application destination of the epidemic algorithm The present invention is applicable to technology.

  In addition, between communication terminals (devices) to which the above-described technology is applied, information held periodically between adjacent communication terminals (devices) and the state of communication terminals (devices) are notified, and changes or differences between adjacent terminals are detected. If there is, the information is exchanged. As an example, in the notification of the routing table, its routing table is periodically broadcast and notified. In order to apply to these technologies, it is possible to apply the present invention by grasping that the information notification operation performed periodically is the same as the SV exchange described in the embodiment of the present invention. Is possible.

  Further, by applying the present invention, it is possible to quickly transmit highly important information or urgent information to the surroundings without being limited by the regular information transmission (exchange) interval.

  Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. 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.

  This application claims the priority on the basis of Japanese application Japanese Patent Application No. 2010-062287 for which it applied on March 18, 2010, and takes in those the indications of all here.

Claims (10)

An information sharing method for sharing information held by each of a plurality of communication terminals within a communicable range by radio,
When the communication terminal transmits to the other communication terminal a notification message for notifying information held by the communication terminal to another communication terminal that is a communication terminal other than the communication terminal among the plurality of communication terminals. Investigation processing for investigating whether there is information common to the information held by the communication terminal and the information held by the other communication terminal;
When there is the common information as a result of the investigation, the communication terminal selects at least one information from the common information, and does not notify the selected communication information to the other communication terminal. Change processing for transmitting the changed notification message to the other communication terminal,
When the communication terminal does not have the common information as a result of the investigation, a process of transmitting the notification message to the other communication terminal without changing the notification message;
Whether the communication terminal needs to transmit the notification message based on the received notification message and information held by the communication terminal when the communication message is received by the other communication terminal. The process of determining
An information sharing method for performing a process of transmitting the notification message when it is determined that the notification message needs to be transmitted. An information sharing method for sharing information held by each of a plurality of communication terminals within a communicable range by radio,
After the communication terminal transmits information held by the communication terminal to another communication terminal that is a communication terminal other than the communication terminal among the plurality of communication terminals, the information held by the communication terminal and the other communication Investigation processing to investigate whether there is information common to the information held by the terminal,
If the communication terminal has the common information as a result of the investigation, the communication terminal selects at least one information from the common information and does not notify the other communication terminal of the selected information. Change notification message for notifying the information held by the terminal to the other communication terminal, change processing to send the changed notification message to the other communication terminal,
When the communication terminal does not have the common information as a result of the investigation, a process of transmitting the notification message to the other communication terminal without changing the notification message;
Whether the communication terminal needs to transmit the notification message based on the received notification message and information held by the communication terminal when the communication message is received by the other communication terminal. The process of determining
An information sharing method for performing a process of transmitting the notification message when it is determined that the notification message needs to be transmitted. The information sharing method according to claim 2,
The information sharing method, wherein the communication terminal performs a process of transmitting an identifier of information held by the communication terminal as the notification message. The information sharing method according to any one of claims 1 to 3,
In the investigation process, the communication terminal monitors the information held by the other communication terminal by periodically exchanging the notification message with the other communication terminal, and the reception history of the notification message and An information sharing method comprising investigating whether there is the common information by comparing with information held by the communication terminal. The information sharing method according to any one of claims 1 to 3,
In the information processing method, the investigating process uses, as the common information, information that has been set in advance from when the communication terminal acquires the information held by the communication terminal. The information sharing method according to any one of claims 1 to 5,
The information sharing method, wherein the change process changes the notification message by the communication terminal extracting the selected information from the notification message and deleting the selected information from the notification message. The information sharing method according to any one of claims 1 to 5,
The information sharing method, wherein the change process changes the notification message by rewriting the update date and time of the selected information to a date and time older than the update date and time. The information sharing method according to any one of claims 1 to 5,
The information sharing method, wherein the changing process changes the notification message by the communication terminal replacing the selected information with information that can be distinguished from other information. A communication terminal having a wireless communication function,
When transmitting to the other communication terminal a notification message for notifying the information held by the communication terminal to other communication terminals within a range communicable with the communication terminal, the information held by the communication terminal Investigating whether there is information common to the information held by the other communication terminal, and if there is the common information as a result of the investigation, select at least one information from the common information, A priority control unit that changes the notification message so as not to notify the selected information to the other communication terminal;
When the notification message transmitted by the other communication terminal is received, the exchange detection for determining whether the notification message needs to be transmitted based on the received notification message and information held by the communication terminal. And
As a result of the investigation by the priority control unit, when there is the common information, the message changed by the priority control unit is transmitted to the other communication terminal, and when there is no common information, the notification message is not changed. A communication terminal having an information exchange unit that transmits the notification message when the exchange detection unit determines that the notification message needs to be transmitted. A communication terminal having a wireless communication function,
Among the information held by the communication terminal, a request processing unit that determines whether information requested from another communication terminal within a range in which communication with the communication terminal can be performed is high-priority information;
An information exchange unit for transmitting the requested information to the other communication terminal;
If the request processing unit determines that the requested information is high-priority information, the information exchange unit transmits the requested information to the other communication terminal, and then the communication terminal holds the information. Investigate whether there is information common to the information and the information held by the other communication terminal, and if there is the common information as a result of the investigation, select at least one of the common information And a priority control unit that changes a notification message for notifying other communication terminals within a range communicable with the communication terminal so that the selected information is not notified to the other communication terminal,
When the notification message transmitted by the other communication terminal is received, the exchange detection for determining whether the notification message needs to be transmitted based on the received notification message and information held by the communication terminal. And
The information exchange unit transmits the message changed by the priority control unit to the other communication terminal when there is the common information as a result of the investigation by the priority control unit, and when there is no common information, A communication terminal that transmits a notification message to the other communication terminal without change, and transmits the notification message when the exchange detection unit determines that the notification message needs to be transmitted.

Images