JP2007173941A - Wireless communication terminal, wireless multi-hop network, transfer control method, program, and recording medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wireless multi-hop network constituted of a wireless communication terminal determining an efficient data transfer path dynamically. <P>SOLUTION: The wireless communication terminal comprises a transfer control table 107 for managing the transfer state for every data of content, a table 106 for managing its own resource required for transferring the data of content, and a transfer control processing section 103 for generating or analyzing control data exchanged in order to establish communication with other wireless communication terminal based on the transfer state and its own resource. These configurations are provided commonly when each wireless communication terminal functions as a transmission terminal, a relay terminal, or a receiving terminal. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to transfer control in a wireless multi-hop network.

  A wireless multi-hop network is a technology that expands the communication range of wireless communication by wireless communication terminals transferring packets of other wireless communication terminals in a bucket-relay manner, in terms of network autonomy and terminal mobility. Has been attracting attention. Among them, various uses of content distribution such as audio and video distribution have been proposed for multicast communication in which data is distributed from one transmitting terminal to a plurality of receiving terminals on a wireless multi-hop network.

  Multicast communication by wireless communication uses the broadcast property of wireless communication and can be received by a plurality of receiving terminals by one transmission, which is efficient in terms of data transfer. On the other hand, in the case of this form, it is inefficient to perform arrival confirmation of each receiving terminal, and there is a side that reliability is not secured. If reliability is not ensured, a plurality of data transmissions overlap, a collision occurs, and the data is not distributed. Such a situation is conspicuous in multicast communication, but there is a similar situation in unicast communication.

The above situation will be specifically described with reference to the drawings. FIG. 13 illustrates a network configuration example of a conventional wireless multi-hop network. As a multicast routing protocol on this wireless multi-hop network, a method using ODMRP (On Demand Multicast Routing Protocol) presented in the following reference will be described.
(Reference: SUNG-JU LEE, 2 others, “On-Demand Multicast Routing Protocol in Multihop Wireless Mobile Networks”, Mobile Networks and Applications Volume 7, Issue 6 (December 2002), Pages 441-453)

  A wireless multi-hop network is formed by the wireless communication terminals S11, R11, R12, N11, N12, N13, and N14. S11 functions as a transmission terminal, N11, N12, N13, and N14 function as relay terminals, and R11 and R12 function as reception terminals. The radio wave reachable distance of each terminal is a dotted circle area centered on each terminal. Terminals within the radio wave reachable range can communicate with each other, and S11, R11, and R12 cannot communicate directly, but if relay terminals N11 and N12 become transfer terminals and transfer transmission data of S11 sequentially, R11 , R12 can receive the data of S11. ODMRP expresses that it becomes this forwarding terminal as “belonging to FG (Forwarding Group)”. In the following description, “FG” represents a relay terminal that transfers data of a transmission terminal. When there are a plurality of contents to be transferred, each relay terminal can be an FG for each content. Also, the relay terminal to be FG is written as “FGXX” (XX is an arbitrary number).

  In FIG. 13, DATA11 to DATA17 indicate data of contents transferred between the wireless communication terminals. Of these, DATA13 and DATA14 are illustrated by separate arrows, but since the destination of the packet is actually a multicast address, a single transmission operation by the relay terminal N12 is performed to a plurality of receiving terminals R11 and R12. Will be received. Therefore, in the example of FIG. 13, the content data transmitted by the transmission terminal S11 using DATA11 is received by both the reception terminals R11 and R12 in two transfer operations, the transfer operation of the relay terminal N11 and the transfer operation of the relay terminal N12. It will be possible. At this time, the relay terminal N11 is FG11, and the relay terminal N12 is FG12.

  Here, in the prior art, since there is no means for determining an efficient FG, in addition to the relay terminals N11 and N12, the relay terminals N13 and N14 are also FG (corresponding to FG13 and FG14, respectively). The transmission terminal S11 transmits DATA11 and DATA15 to the relay terminals N13 and N14 as one multicast packet, respectively. The content data transmitted by the transmitting terminal S11 using DATA15 is received by the receiving terminal R11 through two transfer operations, ie, the transfer operation of the relay terminal N13 and the transfer operation of the relay terminal N14. Eventually, the data of the same content transmitted by the transmission terminal S1 is inefficient because a total of four transfer operations are performed by the four FGs of the relay terminals N11, N12, N13, and N14. If the relay terminals N13 and N14 are not FG, this situation does not occur. In addition, DATA14 transmitted by relay terminal N12 and DATA17 transmitted by relay terminal N14 match the `` hidden terminal problem '' of the CSMA / CA (Carrier Sense Multiple Access with Collision Avoidance) wireless communication method, and near receiving terminal R11. A collision occurs, causing a situation where the probability that the receiving terminal R11 cannot receive data normally increases.

  Next, a transfer control method performed in the configuration example of this conventional wireless multi-hop network will be described. FIG. 14 is a sequence chart showing a transfer control method using a conventional wireless multi-hop network. In FIG. 14, “JQ” is an abbreviation for control data Join Query, which will be described later, and “JR” is an abbreviation for control data Join Reply.

  According to the conventional technique, while content transmission data exists in the transmission terminal S11, the transmission terminal S11 periodically issues a JoinQuery packet JQ (1), which is control data for searching for a recipient. JQ packets are transferred from time to time by JQ (1) to JQ (5) so that the JQ packet is distributed to all terminals existing in the wireless multi-hop network using a technique called flooding.

  Upon receiving JQ (4) from the relay terminal N12, the receiving terminal R12 transmits a JoinReply packet JR (1), which is control data for displaying the content data reception intention, to the relay terminal N12. This JR traces the route along which the JQ was transferred in reverse, and reaches the relay terminals N12, N11, and S11 sequentially as JR (1) to JR (3). At this time, the relay terminal N12 that has received JR (1) updates the FG12 state in order to transfer the content data, and the relay terminal N11 that has received JR (2) also enters the FG11 state in order to transfer the content data. Update.

  The receiving terminal R11 receives JQ (4) from the relay terminal N12 and JQ (5) from the relay terminal N14. In the conventional method, since there is no means for deciding which of the receiver search JQ (4) and JQ (5) received by the receiving terminal R11 should send the JR, in the example of FIG. ) For the time being transmitted to the relay terminal N14. This JR traces the route through which the JQ was transferred in reverse, and reaches the relay terminals N14, N13, and S11 sequentially as JR (4) to JR (6). At this time, the relay terminal N14 that has received JR (4) updates the FG14 state in order to transfer the content data, and the relay terminal N13 that has received JR (5) also enters the FG13 state in order to transfer the content data. Update.

  The exchange of control data shown in FIG. 14 is performed periodically, but since four terminals of relay terminals N11, N12, N13, and N14 are FG, JQ (4) and JQ (5 ) Will cause a collision in the reception of both, and will cause problems in JR transmission. As a result, inefficiency in data transfer of content data is caused.

  As described above, inefficiency of data transfer has a drawback that the probability of collision increases and the data arrival rate deteriorates. In addition, useless data transfer exerts a negative influence on other communication quality by pressing resources such as wireless communication resources, CPU (Central Processing Unit) loads, and batteries. Therefore, a means for dynamically determining an efficient data transfer path is required.

Even if the invention described in “Path control method and packet transmission apparatus capable of using the method” in Patent Document 1 is used, an efficient data transfer path cannot be dynamically determined. to decide. This is because the present invention measures the traffic situation (throughput, packet loss rate, delay, etc.) of radio links between terminals, and identifies and excludes new paths by identifying and excluding radio links with poor communication quality from the measurement results. This is because the route to be determined may not converge in this method. For example, when a plurality of contents are transmitted, the route cannot be changed for each content. Therefore, all of a plurality of traffic corresponding to the contents are concentrated on a route related to a wireless link with good communication quality. The wireless link on the route where the traffic is concentrated cannot be said to have good communication quality anymore, and a new route must be selected again. It will lead to efficiency.
In addition, since the communication quality of the wireless link on the constructed route is measured and bad wireless links are excluded, the communication quality is not measured at the initial stage of route construction, so the communication quality is poor. There is also a problem that the route may include a wireless link or a forwarding node having a low processing capability that does not satisfy the resources (bandwidth, CPU capability, etc.) required by the content. Therefore, the above judgment is reached.
JP 2005-252496 A

  In view of the above circumstances, an object of the present invention is to provide a wireless multi-hop network configured by wireless communication terminals that dynamically determine an efficient data transfer path.

  An aspect of the present invention that achieves the above object includes a transfer control table that manages a transfer state for each content data, a resource management table that manages its own resources required for transferring the content data, and the transfer The present invention relates to a wireless communication terminal having a transfer control processing unit that generates or analyzes control data to be exchanged to establish communication with another wireless communication terminal based on a state and its own resource.

  When transmitting content data, the wireless communication terminal analyzes the control data and generates control data to which a content request resource is added. In addition, when relaying content data, the control data is analyzed, and control data to which data for identifying itself, data for its own resources, and data for its own transfer state are added is generated. In addition, when content data is received, the control data is analyzed, and control data to which data for identifying itself is added is generated.

  Another aspect of the present invention relates to a wireless communication terminal characterized by managing its own transfer state and its available resources for each content data.

  Further, according to another aspect of the present invention, for each piece of content data, the own transfer state and own available resource are compared with the content request resource added to the control data, and whether or not the resource necessary for communication can be secured. It is related with the radio | wireless communication terminal characterized by these.

  Further, according to another aspect of the present invention, in a wireless multi-hop network that transfers content data in a plurality of wireless communication terminals, each wireless communication terminal uses its own transfer state and its resources for each content data. Based on this, control data to be exchanged to establish communication with another wireless communication terminal is generated or analyzed.

  Further, according to another aspect of the present invention, in a wireless multi-hop network that transfers content data in a plurality of wireless communication terminals, each wireless communication terminal can use its own transfer status and its own use for each content data. It is characterized by managing resources.

  Further, according to another aspect of the present invention, in a wireless multi-hop network that transfers content data in a plurality of wireless communication terminals, each wireless communication terminal can use its own transfer status and its own use for each content data. The resource is compared with the content request resource added to the control data, and it is determined whether or not the resource required for communication can be secured.

  According to another aspect of the present invention, there is provided a wireless multi-hop network transfer control method for transferring content data in a plurality of wireless communication terminals, wherein each wireless communication terminal has its own transfer state for each content data. An exchange process for exchanging control data with another wireless communication terminal to establish communication based on its own resource, and a path selection process for selecting a transfer path of content data based on the control data. Features.

  Here, in the wireless communication terminal that performs the route selection step, a request resource subtraction step that determines whether or not to subtract the request resource related to the wireless communication terminal that relays the transfer from the selected transfer route, and relay the transfer A request resource addition step of determining whether or not to add a request resource related to a wireless communication terminal other than the wireless communication terminal to be added.

  According to another aspect of the present invention, in a wireless multi-hop network program that causes a computer to transfer content data at a plurality of wireless communication terminals, each wireless communication terminal transfers its own data for each content data. Control data to be exchanged to establish communication with another wireless communication terminal is generated or analyzed based on the state and its own resource.

  According to another aspect of the present invention, in a wireless multi-hop network program that causes a computer to transfer content data in a plurality of wireless communication terminals, each wireless communication terminal transfers its own data for each content data. It is characterized by managing the state and its available resources.

  According to another aspect of the present invention, in a wireless multi-hop network program that causes a computer to transfer content data at a plurality of wireless communication terminals, each wireless communication terminal transfers its own data for each content data. The state and its own available resource are compared with the content request resource added to the control data, and it is determined whether or not a resource necessary for communication can be secured.

  Another aspect of the present invention relates to a recording medium storing the above program.

According to the present invention, wireless communication terminals constituting a wireless multi-hop network can dynamically determine an efficient data transfer path. This is because each wireless communication terminal manages the transfer state information and resource information, and exchanges the information with other wireless communication terminals, thereby efficiently selecting the transfer path based on the information. This is because a simple route can be determined dynamically.
In addition, it is possible to construct a data transfer path in which resources required by content are secured. This is because each wireless communication terminal manages transfer state information and resource information, and can construct only a route satisfying the resource requested by the content when constructing the route.

  The best mode for carrying out the wireless multi-hop network of the present invention will be described below. In the description, the drawings submitted at the same time as this specification will be appropriately referred to.

<Constitution>
FIG. 1 illustrates a network configuration example of a wireless multi-hop network according to this embodiment. ODMRP is used as a multicast routing protocol on this wireless multi-hop network.

  A wireless multi-hop network is formed by the wireless communication terminals S11, R11, R12, N11, N12, N13, and N14. S11 functions as a transmission terminal, N11, N12, N13, and N14 function as relay terminals, and R11 and R12 function as reception terminals. However, there are no restrictions on the number or arrangement of wireless communication terminals, and the case of moving during communication is also considered. For this reason, each wireless communication terminal joins, leaves, and moves with respect to the network, and one wireless communication terminal may simultaneously function as a transmission terminal, a relay terminal, and a reception terminal. All of the wireless communication terminals have means for exhibiting the function, which will be described later.

  The radio wave reachable distance of each terminal is a dotted circle area centered on each terminal. Terminals within the radio wave range can communicate with each other, and S11 and R11, R12 cannot communicate directly, but if relay terminals N11, N12 become transfer terminals and transfer the transmission data of S11 sequentially, R11 , R12 can receive the data of S11. Therefore, the relay terminals N11 and N12 correspond to “FG11” and “FG12”, respectively.

  In FIG. 1, DATA11 to DATA14 indicate content data transferred between the wireless communication terminals. Among these, DATA13 and DATA14 are received by a plurality of receiving terminals R11 and R12 by one transmission operation by the relay terminal N12. Accordingly, in the example of FIG. 1, the content data transmitted by the transmission terminal S11 using DATA11 is received by both the reception terminals R11 and R12 in two transfer operations, the transfer operation of the relay terminal N11 and the transfer operation of the relay terminal N12. It will be possible.

  At this time, in the present embodiment, unlike the prior art, FG is determined efficiently, so the relay terminals N13 and N14 are not set to FG. The relay terminal N13 is located within the receivable range of DATA11 transmitted by the transmission terminal S11, but does not perform two transfer operations of the transfer operation of the relay terminal N13 and the transfer operation of the relay terminal N14. As a result, unlike the prior art, only two transfer operations are required, which is efficient. In addition, there is no collision near the receiving terminal R11, and the situation where the receiving terminal R11 cannot receive data normally does not occur. A method for efficiently determining FG will be described later.

  Next, the internal configuration of the wireless communication terminal will be described. FIG. 2 illustrates an internal configuration of the wireless communication terminal 100 according to the present embodiment. It includes an antenna 101, a wireless processing unit 102, a transfer control processing unit 103, a multicast data processing unit 104, a control data cache 105, a resource management table 106, a transfer control table 107, a communication buffer 108, and an application processing unit 109. Yes. Each unit shown here has a common configuration when each wireless communication terminal functions as a transmission terminal, a relay terminal, and a reception terminal in executing the transfer control method of this embodiment. Although not shown in FIG. 2, the wireless communication terminal 100 includes a CPU (Central Processing Control) for each unit and a ROM (Read Only Memory) as a recording medium storing a program read when the CPU performs the central processing control. )have.

  The antenna 101 has a function of transmitting or receiving radio waves when performing wireless communication with other wireless communication terminals. The wireless processing unit 102 has a function of performing data processing related to wireless communication with other wireless communication terminals.

  The application processing unit 109 has a function of analyzing the contents and executing an actual job or service. For example, in the case of video content, the image is displayed on a display provided in the wireless communication terminal 100. The communication buffer 108 has a function of temporarily storing information as a result executed by the application processing unit 109.

  The transfer control table 107 holds data necessary for transfer control and has a function of managing the transfer state for each content data. Necessary data is the process of dynamically determining an efficient FG, such as the FG status for each content, the receiving terminal list that is a list of receiving terminals that can receive content data by becoming FG, and the resources used Data required to execute

  The control data cache 105 has a function of temporarily holding control data that is information exchanged with another wireless communication terminal in order to establish a multicast communication state with the other wireless communication terminal.

  The resource management table 106 has a function of managing its own resources. Here, the “resource” is a resource necessary for transferring content. For example, bandwidth, delay, packet size, wireless stability, etc. can be considered as communication resources, and CPU capacity, remaining battery capacity can be considered as terminal resources.・ The priority given logically can be considered. In the following description of this embodiment, only the band will be described as an example for simplicity. Accordingly, it is assumed that the resource management table 106 manages only the bandwidth as the communication resource owned by itself. However, it is not limited to such an implementation form.

  The multicast data processing unit 104 has a function of performing multicast communication on the content data of the application processing unit 109 via the communication buffer 108. In addition, referring to the transfer control table 107, when the device itself is an FG, it has a function of transferring content data to another wireless communication terminal.

  The transfer control processing unit 103 has a function of generating and analyzing control data held in the control data cache 105. In executing the process of dynamically determining an efficient transfer path, the control data cache 105, the resource management table 106, and the transfer control table 107 are referred to.

<Operation>
Next, a transfer control method performed in the configuration example of the wireless multi-hop network of this embodiment will be described. FIG. 3 is a sequence chart showing a transfer control method by the wireless multi-hop network of this embodiment. In FIG. 3, “JQE” is an abbreviation for control data Join Query Extension described later, and is an extension of “JQ”. “JRE” is an abbreviation for control data Join Reply Extension, and is an extension of “JR”.

  The data structure of JQE is expressed as shown in FIG. In FIG. 4, “Type” is the type of control data, “Reserve” is a spare area, “TTL” is the maximum number of transfers of control data, “Hop Count” is the number of times control data is transferred, “Multicast Group ID” "Sequence number" is a serial number for detecting duplication of control data, "Multicast transmission terminal ID" is an identifier for identifying a transmission terminal that transmits content data, and "Transfer source terminal ID" is control data Is the identifier of the terminal that last transferred. The above information is also used in JQ according to the prior art.

  JQE extends JQ by adding the information described below. “Content request resource” is information on the resource required by the content data, “Relay terminal ID XX” is the identifier of the relay terminal (XX is a number assigned to the terminal), and “Resource management table information XX” The information in the resource management table 106 of the relay terminal identified by “relay terminal ID XX”, “transfer control table information XX”, is the information in the transfer control table 107 identified by “relay terminal ID XX”. “Relay terminal ID XX”, “resource management table information XX”, and “transfer control table information XX” are sequentially added by the relay terminal every time control data is transferred as a packet.

  The data structure of JRE is represented as shown in FIG. “Type” is the type of control data, “Reserve” is the spare area, “Multicast group ID” is the content identifier, “Transfer source terminal ID” is the identifier of the terminal that last transferred the control data, and “Sequence number” is the control Serial number for detecting duplication of data, “Multicast transmission terminal ID XX” is an identifier for identifying the transmission terminal that transmits content data (XX is a number assigned to the terminal), and “Next hop terminal ID XX” transmits control data It is an identifier of the next terminal to be transferred in the terminal direction. The above information is also used in the conventional JR. Note that FIG. 5 does not show a part of JR according to the prior art, which is not necessary for explaining the present embodiment.

  JRE extends JR by adding the information described below. The “receiving terminal ID” is an identifier of the receiving terminal that generated the control data.

  The transfer control method of this embodiment is as follows. While there is content transmission data in the transmission terminal S11, the transmission terminal S11 periodically issues JQE (1), which is control data for recipient search. The transmitting terminal S11 writes the amount and number of resources necessary for transferring content data (here, band 2 for explanation) in the “content request resource” of the JQE packet and transmits it. JQE (1) to JQE (5) are transferred from time to time by the wireless communication terminal so that the JQE packet is spread to all the wireless communication terminals existing in the network by flooding.

  When transferring the JQE, the resource management table 106 managed by the wireless communication terminal is compared with the content request resource. If the request resource is not satisfied, the JQE transfer may not be performed. Since a route that uses the relay terminal that has stopped JQE transfer as a transfer node (FG) is not established, there is an effect that the resource requested by the content is guaranteed in advance at the route construction stage. This determination also has the effect of reducing unnecessary flooding operations. When JQE is transferred, the resource possessed by the content request resource is compared, and if the requested resource is satisfied, the resource (band 2) is reserved in the resource management table 106 and the flooding operation is performed. The reserved resource is updated from a resource reserved state to a resource reserved state by a resource management table update process that is processed when a JRE is received, which will be described later. In the example of FIG. 3, the relay terminals N14 and N13 do not receive the JRE, but the resources reserved in the resource management table 106 of the relay terminals N14 and N13 are subjected to processing for canceling the reservation state with a timer for a certain time. Is done. The process for canceling the reservation state is omitted in FIG. 3 for simplicity.

  During forwarding due to flooding, the relay terminals N11, N12, N13, and N14 that forward JQE transfer the ID that can identify the wireless communication terminal to “relay terminal ID XX” and the resource management table 106 that the terminal holds. The control table 107 is added to “resource management table information XX” and “transfer control table information XX” of JQE, and JQE is transferred. In addition, the receiving terminals R11 and R12 hold the received JQE in the control data cache 105. Therefore, in the example of FIG. 3, the receiving terminals R11 and R12 can obtain the transfer control table information and the resource management table information of the relay terminals N11 and N12 from JQE (4), and the receiving terminal R11 further receives the JQE ( From 5), transfer control table information and resource management table information of the relay terminals N13 and N14 can be obtained.

  After receiving the first JQE, the receiving terminal R12 waits for a while by the timer process, and then executes the route selection process (S01). By this route selection process, it is determined that JRE as control data is transmitted to JQE (4) for displaying the reception intention of the received content data. In this embodiment, an ID that can be identified by the receiving terminal R12 is written in the “receiving terminal ID” in this JRE, and JRE (1) is transmitted to the relay terminal N12. The JRE follows the JQE transferred route in reverse, and sequentially reaches the terminals N12, N11, and S11. At this time, the relay terminal N12 that has received the JRE (1) updates the FG12 state in order to transfer the content data (S02), and in the transfer control table 107 held by the relay terminal N12, “reception terminal ID” Is updated in the receiving terminal list (S03), the resource reserved when the JQE is transferred is secured, and the resource management table 106 is updated (S03). The relay terminal N11 that has received the JRE (2) also updates the FG11 state to transfer the content data (S04), updates the transfer control table 107 (S05), and updates the resource management table 106 (S05). .

  After receiving the first JQE, the receiving terminal R11 waits for a while by the timer process, and then executes the route selection process (S06). By this route selection process, it is determined that JRE is transmitted to JQE (4). In the JRE, an ID that can be identified by the receiving terminal R11 is written in the “receiving terminal ID”, and JRE (4) is transmitted to the relay terminal N12. The JRE follows the JQE transferred route in reverse, and sequentially reaches the terminals N12, N11, and S11. At this time, the N12 that has received JRE (4) updates the FG12 state in order to transfer the content data (S07), and receives the “receiving terminal ID” in the transfer control table 107 held by the relay terminal N12. The terminal list is additionally updated (S08), the resources reserved when the JQE is transferred are secured, and the resource management table 106 is updated (S08). The relay terminal N11 that has received the JRE (5) also updates the FG11 state in order to transfer the content data (S09), additionally updates the transfer control table 107 (S10), and updates the resource management table 106 (S10). .

  In this embodiment in which only the bandwidth is used as an example of the resource, the update process (S03, S05, S08, S10) of the resource management table 106 is a predetermined value (here, The bandwidth 2 reserved in the resource management table 106 at the time of JQE transfer from the bandwidth 10 for the purpose of explanation is subtracted from the bandwidth 10 of the specified value to secure the resources, and the available resources are bandwidth 8 (S03, S05) Is applicable). If it is determined with reference to the transfer control table 107 that the same multicast group ID is transferred, the subtraction process is not performed because the resource has been secured (S08 and S10 are applicable).

  The exchange of control data shown in FIG. 3 is periodically performed. In this embodiment, the two wireless communication terminals N11 and N12 are FG.

  Although omitted in FIG. 3, the FG state of the relay terminals N11, N12, N13, and N14 is canceled when there is no exchange of JQE and JRE due to the terminal moving over time. In this case, processing is performed to add the reserved bandwidth 2 to the bandwidth 8 of the resource management table 106 of each terminal for resource return, and to set the available resource to the bandwidth 10.

  Here, the route selection process shown in FIG. 3 will be described. FIG. 6 is a flowchart regarding route selection processing. FIG. 7 illustrates a flowchart related to the “request resource subtraction process” in FIG. 6, and FIG. 8 illustrates a flowchart related to the “request resource addition process” in FIG. The requested resource subtraction process is a process for determining whether or not to subtract the requested resource related to the wireless communication terminal that relays the transfer with respect to the selected transfer path. The requested resource addition process is a process for determining whether or not to add a requested resource related to a wireless communication terminal other than the wireless communication terminal that relays the transfer.

  The receiving terminals R11 and R12 create a network status list as shown in FIG. 9 (S01). In the example of FIG. 3, the receiving terminals R11 and R12 can obtain the transfer control table information 11 and 12 and the resource management table information 11 and 12 of the relay terminals N11 and N12 by JQE (4). Transfer control table information 11 and 12 and resource management table information 11 and 12 of relay terminals N13 and N14 can be obtained by JQE (5). FIG. 9 shows an example of a network status list created by the receiving terminal R11 from JQE (4) and JQE (5). From FIG. 9, as for receiving terminal R11, relay terminals N11, N12, N13, and N14 are FGs of content data whose multicast group ID is “1”, respectively, and resources can be used by consuming only band 2. It can be understood that the resource is in the band 8 state.

  In the example of FIG. 3, the receiving terminal R12 has received only JQE (4), and since there is only one route that can be selected, as a result, the route of JQE (4) is selected. Therefore, the description of the route selection process of R12 is omitted.

  The receiving terminal R11 processes all the JQEs in the control data cache 105 from the network state list in FIG. 9 (S02 to S05 in FIG. 6). Since JQE (4) and JQE (5) are held in the control data cache 105 of the receiving terminal R11, the request resource subtraction process (S03) and the request resource addition process (S04) are performed on each.

  In the flowchart of the requested resource subtraction process in FIG. 7, the receiving terminal processes all the relay terminal IDs stored in JQE (S01 to S05 in FIG. 7). When the same relay terminal ID as the JQE relay terminal ID is in the network status list (Yes in S02) and the corresponding terminal is not already the same multicast group ID FG (No in S03), the requested resource Minutes are subtracted (S05). This is repeated for each relay terminal ID.

  First, the receiving terminal R11 calculates the state when the JQE (4) route, that is, the route with the relay terminals N11 and N12 as FG is selected from the network state list of FIG. In this process, the receiving terminal R11 acquires necessary resources from the “content request resource” of JQE (4) (here, band 2), and calculates a state in which the necessary resources are secured from the resources of FIG. Since JQE (4) is routed through the relay terminals N11 and N12, the resources of the relay terminals N11 and N12 are targeted in the determination S02 in FIG. 7 (Yes in S02 in FIG. 7), and the relay terminal N11 in the determination S03. , N12 is the forwarding node (FG) of the receiving terminal R12 having the same multicast group ID 1 as R11 (Yes in S03 in FIG. 7), and therefore no subtraction is performed.

  After the request resource subtraction process, a request resource addition process is performed (S04 in FIG. 6). In the request resource addition process in FIG. 8, the relay terminal IDs in the network status list that are not processed in the request resource subtraction process are processed (S01 to S05 in FIG. 8). If the multicast group ID related to the FG of the target relay terminal ID is the same multicast group ID (Yes in S02) and the receiving terminal list is only the own terminal ID (Yes in S03), the addition for the requested resource (S04).

  When the JQE (4) route is selected from the network status list of FIG. 9, the routes of the relay terminals N13 and N14 are not used. Then, the relay terminals N13 and N14 are currently forwarding nodes (FG) of the receiving terminal R11 (Yes in S02 in FIG. 8), and the route is selected in the receiving terminal list of the receiving terminals R11 and R12. Since only the IDs of the relay terminals N11 and N12, which are their own terminals, are registered (Yes in S03 of FIG. 8), the resources of the relay terminals N13 and N14 are added by the band 2 in the request resource addition process to 10 (FIG. 8 S04). A list of network states obtained as a result of these processes is shown in FIG. The relay terminals N11 and N12 are transfer terminals for both the receiving terminals R11 and R12.

  Next, the receiving terminal R11 calculates the state when the route of JQE (5), that is, the route with the relay terminals N13 and N14 as FG is selected from the network state list of FIG. The receiving terminal R11 acquires necessary resources from the “content request resource” of JQE (5), and calculates a state in which the necessary resources are secured from the resources of FIG. Since JQE (5) is routed through the relay terminals N13 and N14, the resources of the relay terminals N13 and N14 are targeted by the determination in S02 of FIG. 7 (Yes in S02 of FIG. 7), but in S03 of FIG. As a result of the determination, the relay terminals N13 and N14 are forwarding nodes of the receiving terminal R11 itself (Yes in S03 in FIG. 7), and therefore, the subtraction for the requested resource is not performed. Furthermore, when the JQE (5) route is selected, the receiving terminal R11 does not use the routes of the relay terminals N11 and N12. Then, from FIG. 8, the relay terminals N13 and N14 are currently forwarding nodes (FG) of the receiving terminal R11 (Yes in S02 of FIG. 8), but in FIG. 9, the relay terminals N11 and N12 are own terminals. It is a transfer terminal of the receiving terminal R12 different from the receiving terminal R11 (No in S03 of FIG. 8). Therefore, the required resource is not added. FIG. 11 shows a list of network states obtained as a result of these processes.

  The receiving terminal R11 compares the network state list after selecting the JQE (4) route (FIG. 10) with the network state list after selecting the JQE (5) route (FIG. 11), and the resource is effective. The available state, in this example, the state of FIG. 10 in which the total of the remaining available bandwidth is maximized is validated, and as a result, the route of JQE (4) is selected. In this selection, for the effect of load distribution, it is possible to implement a method such as selecting a path with less overlap with different group IDs or a path with minimum resource distribution. Thereafter, the receiving terminal R11 calculates all the JQEs in the control data cache 105, finally determines a route in the route determination process (S06 in FIG. 6), and transmits the JRE addressed to the route. . The receiving terminal R11 erases the JQE in the control data cache 105. The content data is transferred using the determined route.

By implementing this embodiment, the following effects can be obtained. That is, first, efficient data transfer can be performed in a wireless multi-hop network. The reason is that each wireless communication terminal is provided with means for managing the transfer state and resources using the transfer state table and the resource management table, exchanging the information, and means for determining the route based on the information. This is to dynamically determine a specific route.
The transfer state and resources managed by each wireless communication terminal are elements derived from the absolute performance of the wireless communication terminal itself, and the route can be determined for each content data by such management. There is no possibility that the determined route will not converge. This is because the communication quality of the wireless link is not considered.

  Also, load distribution of data transfer terminals can be performed in a wireless multi-hop network. The reason is that each wireless communication terminal stores a transfer state and a resource, so that a route for load distribution is dynamically determined for each content or each receiving terminal.

  In addition, it is possible to increase the data arrival rate in the wireless multi-hop network. The reason for this is that efficient data transfer performs transfer with less data loss due to data collision specific to wireless communication, which is represented by the hidden terminal problem. Further, the load distribution of the data transfer terminals eliminates concentration of the transfer data on the terminals and prevents data discard due to congestion.

  In addition, data quality can be ensured in a wireless multi-hop network. The reason for this is that “content request resource” is indicated in the control data (JQE) for recipient search, so that the recipient search can be performed while referring to and comparing with the resources managed by each wireless communication terminal. This is because it becomes possible. This is also because the transfer terminal can secure resources for each content according to the requested resource. For this reason, the problem that the path | route which does not satisfy the resource which a content requires is constructed | assembled in the path | route construction initial state as assumed from invention of patent document 1 does not generate | occur | produce.

  In addition, although the form mentioned above is the best form for implementing the radio | wireless multihop network of this invention, it is not the meaning limited to this form. Therefore, various modifications can be made to the implementation form without changing the gist of the present invention.

  Another embodiment according to the modified embodiment will be described. FIG. 12 illustrates a network configuration example of another form of wireless multi-hop network. ODMRP is used as a multicast routing protocol on this wireless multi-hop network. In this embodiment, an example will be described in which the load is distributed by the transfer control method of the present invention when transferring contents of another multicast group.

  FIG. 12 shows a state in which multicast transmission of data of two contents having different contents (one indicated by a black arrow and one indicated by a white arrow) is performed from the transmission terminal S11. In FIG. 12, DATA11 to DATA14 indicate contents data of multicast group ID1 (indicated by black arrows), and DATA15 to DATA18 indicate contents data of multicast group ID2 (indicated by white arrows). DATA11 and DATA12 are illustrated by separate arrows, but in actuality, they are performed by a single transmission operation of multicast group ID1 by the transmission terminal S11. DATA15 and DATA16 are also illustrated by separate arrows, but are performed by a single transmission operation of multicast group ID2. R12 is a receiving terminal of multicast group ID 1, and R11 is a receiving terminal of multicast group ID 2.

  By performing the route selection process (see FIGS. 6 to 8) described in the best mode, the content data route of the multicast group ID1 is changed to the terminals S11, N11, N12, and R12, and the content data route of the multicast group ID2 is set. Can be used as terminals S11, N13, N14, and R11, and load distribution of the transfer terminals can be realized.

  In the wireless multi-hop network of the present invention, a protocol other than ODMRP can be used. Further, it can be applied not only to one-to-many multicast communication but also to many-to-many multicast communication and one-to-one unicast communication.

In unicast communication, for example, it can be applied to unicast communication by AODV (Ad hoc On-demand Distance Vector) protocol in IETF (Internet Engineering Task Force) MANET (Mobile Ad hoc NETwork Working Group) of the following references. In the AODV protocol, since a route is determined based on control data that arrives earliest, there is a problem that data to another receiving terminal may be concentrated on a certain transfer terminal. However, if the present invention is applied, the route is determined based on the resource of the transfer route, and the relay terminal can manage the transfer route for each receiving terminal. It becomes possible to distribute the load. In addition, it is possible to secure communication resources in the transfer terminal by using the content request resource of the control data.
(Reference: C. Perkins, two others, “Ad hoc On-Demand Distance Vector (AODV) Routing”, IETF RFC3561, (July 2003))

  The present invention can be applied to various services using the wireless multi-hop network of the present invention. For example, by using the broadcast property of multicast communication, broadcasting services such as television and radio, emergency communication for disaster prevention, communication between vehicles or road-to-vehicle, communication with vehicles such as vehicles, aircraft, ships, or sensors -It can also be applied to methods such as simultaneous control of robots. Further, it can be used for unicast communication between terminals accompanying movement.

It is a network structural example of the radio | wireless multihop network of this form. 1 illustrates an internal configuration of a wireless communication terminal 100 according to the present embodiment. It is a sequence chart showing the transfer control method by the radio | wireless multihop network of this form. The data structure of JQE is illustrated. The data structure of JRE is illustrated. 2 is a flowchart related to route selection processing. 6 is a flowchart illustrating a request resource subtraction process. 10 is a flowchart related to request resource addition processing. FIG. 6 shows a list of network states created by route selection processing. The network state list after selecting the route (JQE (4) route) with the relay terminals N11 and N12 as FG is illustrated. The network state list after selecting the route (JQE (5) route) with the relay terminals N13 and N14 as FG is illustrated. It is a network structural example of the wireless multihop network of another form. It is a network structural example of the conventional wireless multihop network. It is a sequence chart showing the transfer control method by the conventional wireless multihop network.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Wireless communication terminal 101 Antenna 102 Wireless processing part 103 Transfer control processing part 104 Multicast data processing part 105 Control data cache 106 Resource management table 107 Transfer control table 108 Communication buffer 109 Application processing part

Claims (15)

A transfer control table for managing the transfer status for each content data;
A resource management table for managing own resources required for transferring content data;
A wireless communication terminal having a transfer control processing unit that generates or analyzes control data to be exchanged to establish communication with another wireless communication terminal based on the transfer state and the own resource.   The wireless communication terminal according to claim 1, wherein when transmitting content data, the control data is analyzed to generate control data to which a content request resource is added.   The content data is analyzed when the content data is relayed, and control data to which data for identifying itself, data for its own resource, and data for its own transfer state are added is generated. The wireless communication terminal described in 1.   2. The wireless communication terminal according to claim 1, wherein when receiving content data, the control data is analyzed, and control data to which data for identifying itself is added is generated.   A wireless communication terminal that manages its own transfer state and its available resources for each content data.   Wireless communication characterized in that for each content data, its own transfer status and its available resources are compared with the content request resource added to the control data, and it is determined whether or not resources necessary for communication can be secured Terminal. In a wireless multi-hop network that transfers content data in a plurality of wireless communication terminals,
Each wireless communication terminal generates or analyzes control data exchanged for establishing communication with another wireless communication terminal based on its own transfer state and its own resource for each content data Wireless multi-hop network. In a wireless multi-hop network that transfers content data in a plurality of wireless communication terminals,
A wireless multi-hop network, wherein each wireless communication terminal manages its own transfer state and its available resources for each content data. In a wireless multi-hop network that transfers content data in a plurality of wireless communication terminals,
For each content data, each wireless communication terminal compares its own transfer status and its available resources with the content request resource added to the control data, and determines whether it is possible to secure resources necessary for communication. A wireless multi-hop network characterized by In a wireless multi-hop network transfer control method for transferring content data in a plurality of wireless communication terminals,
For each content data, each wireless communication terminal exchanges control data with other wireless communication terminals to establish communication based on its own transfer state and its resources,
A transfer control method comprising a route selection step of selecting a transfer route of content data based on the control data. In the wireless communication terminal that performs the route selection step,
A request resource subtraction step for determining whether or not to subtract the request resource related to the wireless communication terminal that relays the transfer for the selected transfer path;
12. The transfer control method according to claim 11, further comprising a request resource addition step of determining whether or not to add a request resource related to a wireless communication terminal other than the wireless communication terminal that relays the transfer. On the computer,
In a wireless multi-hop network program for transferring content data in a plurality of wireless communication terminals,
Each wireless communication terminal generates or analyzes control data to be exchanged for establishing communication with another wireless communication terminal based on its own transfer state and its own resource for each content data program. On the computer,
In a wireless multi-hop network program for transferring content data in a plurality of wireless communication terminals,
A program characterized in that each wireless communication terminal manages its own transfer state and its available resources for each content data. On the computer,
In a wireless multi-hop network program for transferring content data in a plurality of wireless communication terminals,
Have each wireless communication terminal compare its own transfer status and its available resources with the content request resource added to the control data for each content data, and determine whether it is possible to secure the resources required for communication A program characterized by   A recording medium storing the program according to claim 12.

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