JP4798583B2 - WIRELESS NETWORK, WIRELESS DEVICE USED FOR THE SAME, PROGRAM FOR CAUSING COMPUTER SELECTION OF TRANSFER TERMINAL IN THE SAME AND COMPUTER-READABLE RECORDING MEDIUM CONTAINING THE PROGRAM - Google Patents

Description

  The present invention relates to a wireless network, a wireless device used in the wireless network, a program for causing a computer to select a transfer terminal in the wireless network, and a computer-readable recording medium on which the program is recorded. The present invention relates to a network, a wireless device used therefor, a program for causing a computer to select a transfer terminal, and a computer-readable recording medium storing the program.

  An ad hoc network is a network that is autonomously and instantaneously constructed by a plurality of wireless devices communicating with each other. In an ad hoc network, when two wireless devices that communicate with each other do not exist in the communication area, a wireless device located between the two wireless devices functions as a router and relays a data packet. Can be formed.

  Dynamic routing protocols that support multi-hop communication include table-driven protocols and on-demand protocols. The table-driven protocol periodically exchanges control information related to a route, and constructs a route table in advance. The FSR (Fish-eye State Routing), OLSR (Optimized Link State Routing), and TBRPF (Topology) (Dissociation Based on Reverse-Path Forwarding) and the like are known.

  In addition, the on-demand protocol is a method for constructing a route to a destination for the first time when a data transmission request occurs, and includes DSR (Dynamic Source Routing) and AODV (Ad Hoc On-Demand Distance Vector Routing). Are known.

  In an ad hoc network using the OLSR protocol, when a transmission source wireless device transmits a packet to all the wireless devices in the ad hoc network, an MPR (Multipoint Relay) is used to minimize the number of transfer packets in the ad hoc network. Is used (Non-Patent Document 1).

  Also, in an ad hoc network, when each wireless device transmits a packet to all wireless devices in the ad hoc network, a waiting time function is introduced into the duplicate packet check method, and each wireless device has another wireless device within the waiting time. The packet forwarded from is not transmitted (Non-patent Document 2).

Further, in an ad hoc network, when each wireless device transmits a packet to all the wireless devices in the ad hoc network, a transfer process is not performed on a packet transferred by another wireless device (non-patent document). 3).
Clausen, T., Jacquet, P., “Optimized Link State Routing Protocol (OLSR), RFC3626, Oct. 2003. Koide, Kominato, Tanaka, “Study on transmission time of flooding method in multi-hop wireless network”, Information Science and Technology Forum 2003, p341-342 Motegi S., and Horiuchi H., “Relay Control for Data Dissemination of Spontaneous Vehicular Networks”, Proceeding of the 6th International Conference on ITS Telecommunication (ITST'06), pp.1098-1101 (2006).

  However, in the inter-vehicle communication, it is considered as standardization that flooding is used, each vehicle exchanges information at intervals of 100 milliseconds, and the delay time until the arrival of information is 100 milliseconds or less. When a CSMA / CA (Carrier Sense Multiple Access / Collision Avoidance) mechanism such as IEEE 802.11 is used, contention traffic increases and the packet loss rate increases as the number of terminals existing in the network increases.

  Therefore, it is important to develop a mechanism for suppressing useless packet transfer in flooding.

  From this point of view, the MPR method disclosed in Non-Patent Document 1 is not practical because recalculation of MPR sets frequently occurs in an environment where the network topology changes drastically, such as inter-vehicle communication.

  In addition, as a result of implementing the WDD 'Waiting-time Drive Diffusion) algorithm described in Non-Patent Document 2 and performing a verification experiment by combining existing devices, it is normal that the number of wireless devices in the network becomes 10 or more. It turns out that it does not work. This is because each wireless device must manage the content and time for all information generated in the network, and parallel processing is required, so the number of wireless devices existing in the same network is reduced. In many cases, when all wireless devices transmit information, a commercially available PC (Personal Computer) cannot control.

  Furthermore, since the DRD (Duplicate Relay Detection) algorithm described in Non-Patent Document 3 requires the same processing as the WDD algorithm, it is assumed that the operation becomes difficult when the network scale increases.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a wireless network capable of efficiently transferring packets.

  Another object of the present invention is to provide a wireless device used in a wireless network capable of efficiently transferring packets.

  Furthermore, another object of the present invention is to provide a program for causing a computer to execute selection of a transfer terminal in a wireless network capable of efficient packet transfer.

  Furthermore, another object of the present invention is to provide a computer-readable recording medium recording a program for causing a computer to select a transfer terminal in a wireless network capable of efficiently transferring packets.

  According to the present invention, a wireless network is a wireless network that is autonomously established and performs wireless communication between a transmission source and a transmission destination, and includes a first wireless device and n (n is a positive integer). ) Second wireless devices. The first wireless device selects, as a transfer terminal, a wireless device that transfers a packet transmitted by itself to a wireless device that is outside the communication range at the second hop among wireless devices that exist within the communication range of the first wireless device Then, a packet to which the first transfer terminal list that is the list of the selected transfer terminals is added is generated and transmitted. When the n second wireless devices receive a packet including the first wireless device as a transmission source, and the received packet includes the forwarding terminal list and the forwarding terminal list includes itself, Among wireless devices that exist within the communication range, a wireless device that has a relatively low rate of transferring packets from the wireless device that directly transmitted packets to itself at the second hop is selected as the transfer terminal, and the selected device is selected. A second transfer terminal list, which is a list of transfer terminals, is added to the packet instead of the transfer terminal list included in the packet, and the packet is transmitted.

  Preferably, the n second wireless devices, when receiving the packet from the first wireless device, transmit the packet by adding the second transfer terminal list to the packet instead of the first transfer terminal list. .

  Preferably, the first wireless device holds a first received packet statistics list indicating a statistical distribution of the number of hops of a packet delivered to itself from an arbitrary wireless device, and the first received packet statistics list includes Based on this, the transfer terminals constituting the first transfer terminal list are selected. Each of the n second wireless devices maintains a second received packet statistics list indicating a statistical distribution of the number of hops of packets delivered from an arbitrary wireless device to the second received packet statistics. Based on the list, the transfer terminals constituting the second transfer terminal list are selected.

  Preferably, the first wireless device forwards a packet transmitted from an arbitrary wireless device to itself at the second hop based on the first received packet statistics list (j is a positive integer) radios A device is selected, a first transfer terminal candidate list is created in which the selected j wireless devices are rearranged in descending order of the number of packets transferred to the device, and the first transfer terminal candidate list is created. The transfer terminals constituting the first transfer terminal list are selected in order from the top. Each of the n second wireless devices forwards the packet from the wireless device that directly transmitted the packet to itself based on the second received packet statistics list, where k is a positive integer. Select a wireless device, sort the selected k wireless devices in ascending order of the number of packets, with the wireless device with the number of transfer hops being the second hop being zero as the highest order, and rearrange the selected devices A second transfer terminal candidate list composed of k wireless devices is created, and transfer terminals constituting the second transfer terminal list are selected in order from the top of the created second transfer terminal candidate list.

  Preferably, the first wireless device periodically updates the first received packet statistics list, and each of the n second wireless devices periodically updates the second received packet statistics list.

  According to the present invention, the wireless device is a wireless device that is autonomously established and constitutes a wireless network in which wireless communication is performed between a transmission source and a transmission destination. Any one of the first radio apparatus and n second radio apparatuses.

  Furthermore, according to the present invention, a program for causing a computer to execute is autonomously established and requests transfer of a packet in a wireless device used in a wireless network in which wireless communication is performed between a transmission source and a transmission destination. A program for causing a computer to select a transfer terminal to perform, wherein the creation means creates a received packet statistics list indicating a statistical distribution of the hop count of packets delivered from an arbitrary wireless device to the wireless device And the selecting means selects i (i is a positive integer) number of wireless devices that transfer packets from any wireless device to the wireless device in the second hop based on the received packet statistics list. Step 2 and the creation means create a transfer terminal candidate list in which the selected i wireless devices are rearranged in descending order of the number of packet transfers. A step of, is the selection means, a program for executing the fourth step of selecting a wireless device that constitutes the transfer device from the top of the first transfer terminal candidate list created in sequence to the computer.

  Furthermore, according to the present invention, a program for causing a computer to execute is autonomously established and requests transfer of a packet in a wireless device used in a wireless network in which wireless communication is performed between a transmission source and a transmission destination. A program for causing a computer to select a transfer terminal to perform, wherein the creation means creates a received packet statistics list indicating a statistical distribution of the hop count of packets delivered from an arbitrary wireless device to the wireless device And a second means for selecting k (k is a positive integer) number of wireless devices that transfer a packet from the wireless device that has directly transmitted the packet to itself based on the received packet statistics list. And the creation means selects the wireless device having the zero number of packets with the second transfer hop count as the highest and the selected k The third step of rearranging the wireless devices in ascending order of the number of packets, creating a second transfer terminal candidate list composed of the rearranged k wireless devices, and the selection means includes the generated second This is a program for causing a computer to execute the fourth step of selecting the transfer terminals constituting the second transfer terminal list in order from the top of the transfer terminal candidate list.

  Furthermore, according to this invention, the computer-readable recording medium on which the program is recorded is a computer-readable recording medium on which the program according to claim 7 or 8 is recorded.

  In this invention, the source wireless device selects a wireless device that transfers packets to itself at the second hop as a transfer terminal, and the relay terminal that receives the packet from the source wireless device is the source wireless device. A wireless device having a relatively low rate of transferring packets from the second hop is selected as a transfer terminal. As a result, the transfer terminal sequentially transfers packets in a direction in which many wireless devices exist in the wireless network.

  Therefore, according to the present invention, packets can be transferred efficiently.

  Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a schematic diagram of a wireless network according to an embodiment of the present invention. The wireless network 100 according to the embodiment of the present invention includes wireless devices 1 to 14. The wireless devices 2, 5, 7, and 8 exist within the communication range of the wireless device 1, and the wireless devices 1, 5 to 7, 9, and 10 exist within the communication range of the wireless device 8, and 9, 11 to 13 exist within the communication range of the wireless device 10. And each of the radio | wireless apparatuses 1-14 is mounted in a vehicle, for example.

  When each of the wireless devices 1 to 14 floods a packet within the wireless network 100, the wireless device 1-14 selects a transfer terminal that requests transfer of the packet transmitted by the wireless device 100 by a method described later, and indicates the selected transfer terminal. Create a list. Then, each of the wireless devices 1 to 14 creates a packet including the transfer terminal list and transmits the created packet.

  In addition, when each of the wireless devices 1 to 14 receives a packet from another wireless device, the wireless devices 1 to 14 determine whether or not the received packet includes a transfer terminal list. Then, each of the wireless devices 1 to 14 transfers the received packet when the transfer terminal list is not included in the packet. On the other hand, when the transfer terminal list is included in the packet, each of the wireless devices 1 to 14 further determines whether or not the transfer terminal list includes itself, and when the transfer terminal list includes itself, A transfer terminal that requests transfer of the transferred packet is selected by a method described later. Each of the wireless devices 1 to 14 creates a transfer terminal list indicating the selected transfer terminal, updates the transfer terminal list included in the packet with the created transfer terminal list, and transfers the packet.

  Each of the wireless devices 1 to 14 does not transfer the received packet when the wireless devices 1 to 14 do not include the wireless devices 1 to 14.

  FIG. 2 is a schematic block diagram showing the configuration of the wireless device 1 shown in FIG. The wireless device 1 includes an antenna 101, a transmission / reception unit 102, an information creation unit 103, a received packet statistics list 104, a creation unit 105, and a selection unit 106.

  The antenna 101 transmits a packet received from the transmission / reception unit 102 to another wireless device, and outputs a packet received from the other wireless device to the transmission / reception unit 102.

  The transmission / reception means 102 receives the packet PKT transmitted from another wireless device via the antenna 101 and outputs the received packet PKT to the information creation means 103.

  The transmission / reception means 102 detects the wireless device that is the transmission source of the packet PKT received from the antenna 101, and outputs the detected wireless device that is the transmission source to the creation means 105.

  Further, the transmission / reception means 102 determines whether or not the packet PKT received from the antenna 101 includes the transfer terminal list, and when the packet PKT does not include the transfer terminal list, transfers the received packet PKT via the antenna 101. To do. On the other hand, when the packet PKT includes the transfer terminal list, the transmission / reception unit 102 further determines whether or not the wireless device 1 is included in the transfer terminal list. Then, when the wireless device 1 is included in the transfer terminal list, the transmission / reception unit 102 generates a signal REQ for requesting creation of a transfer terminal list including transfer terminals that request transfer of the packet PKT transferred by the wireless device 1. And output to the creating means 105. Thereafter, when the transmission / reception unit 102 receives the transfer terminal list from the selection unit 106, the transmission / reception unit 102 rewrites the transfer terminal list included in the packet PKT with the received transfer terminal list, and transmits the packet PKT including the rewritten transfer terminal list to the antenna 101. Forward through. On the other hand, when the wireless device 1 is not included in the transfer terminal list, the transmission / reception unit 102 does not transfer the received packet.

  The information creation unit 103 generates a packet PKT transmitted by the wireless device 1 and outputs the generated packet PKT to the transmission / reception unit 102. Further, when the wireless device 1 receives the packet PKT received from the other wireless device by the wireless device 1, the information creating unit 103 creates the received packet statistics list 104 by a method described later based on the received packet PKT. To do.

  The received packet statistics list 104 includes a statistical distribution of the number of hops from the wireless devices 2 to 14 to the wireless device 1 when the wireless device 1 receives the packet PKT created by the wireless devices 2 to 14.

  Upon receipt of the signal REQ and the transmission source wireless device from the transmission / reception unit 102, the creation unit 105 refers to the received packet statistics list 104 and uses a method to be described later to transfer terminals that are candidates for transfer terminals that request packet transfer. A candidate list is created, and the created transfer terminal candidate list is output to selection means 106.

  Upon receiving the transfer terminal candidate list from the creation means 105, the selection unit 106 determines, based on the received transfer terminal list, the transfer terminals that request packet transfer from a predetermined number and the number of adjacent terminals, by the method described later. Select the smaller number and create a transfer terminal list consisting of the selected transfer terminals.

  Then, the selection unit 106 outputs the created transfer terminal list to the transmission / reception unit 102.

  Each of the wireless devices 2 to 14 has the same configuration as that of the wireless device 1 shown in FIG.

  FIG. 3 is a configuration diagram of the packet PKT. The packet PKT includes a packet header PHD and a message header MHD.

  The packet header PHD includes a packet length, a packet sequence number, a transmission source address, and a transfer terminal list. The packet length consists of 16-bit data and represents the number of bytes of the packet. The packet sequence number consists of 16-bit data and is used to distinguish which packet is new. The packet sequence number is incremented by “1” every time a new packet is generated. Therefore, the larger the packet sequence number, the newer the packet PKT. The transmission source address is made up of 32-bit data, and is made up of the IP address of the wireless device that generated the packet PKT or the IP address of the wireless device that relays the packet PKT. As will be described later, the transfer terminal list is made up of wireless devices to which each wireless device requests transfer of the packet PKT.

  The message header MHD includes a message type, a valid time, a message size, a source address, a TTL, a hop count, a message sequence number, and a message.

  The message type is composed of 8-bit data and represents the type of message written in the message body, and 0 to 127 are reserved. The valid time consists of 8-bit data, and represents the time when this message must be managed after reception. The valid time is composed of a mantissa part and an exponent part.

  The message size consists of 16-bit data and represents the length of the message. The source address is made up of 32-bit data and represents the wireless device that generated the message. This source address is unchanged. The TTL is composed of 8-bit data and specifies the maximum number of hops to which a message is transferred. The TTL is decremented by “1” when the message is transferred. When TTL is “0”, the message is not transferred. The number of hops consists of 8-bit data and represents the number of hops from the message generation source. The number of hops is initially set to “0” and is incremented by “1” every time it is transferred. The message sequence number consists of 16-bit data and represents an identification number assigned to each message. The message sequence number is incremented by “1” every time a message is created. The message is a message to be transmitted.

  Based on the source address and TTL included in the message header MHD of the packet PKT, the information creation means 103 and creation means 105 of the wireless devices 1 to 14 are the wireless device that transmitted the packet PKT and the wireless device that transmitted the packet PKT. To the number of hops from the wireless device on which it is installed. Since the TTL is decremented by “1” every time the packet PKT is transferred, the information creating unit 103 and the creating unit 105 can detect the number of hops based on the decreased value from the initial value.

  Further, the information creation means 103 and creation means 105 of the wireless devices 1 to 14 detect the wireless device that has transmitted the packet to the wireless device on which it is mounted, based on the transmission source address included in the header PHD of the packet PKT. .

  Then, the information creation means 103 of the wireless devices 1 to 14 creates a received packet statistics list 104 to be described in detail later based on the detected transmission source wireless device, the number of hops, and the transmission source wireless device.

  In addition, the creation unit 105 of the wireless devices 1 to 14 uses the wireless device on which the wireless device 1-14 is mounted by a method described later based on the detected wireless device of the transmission source, the number of hops, the wireless device of the transmission source, and the received packet statistics list. A transfer terminal requesting transfer of a packet transferred by the apparatus is selected, and a transfer terminal candidate list including the selected transfer terminals is created.

  FIG. 4 is a diagram showing the configuration of the received packet statistics list 104 shown in FIG. The received packet statistics list 104 is a distribution of the number of hops from a source node to itself when a wireless device receives a packet transmitted from a source node (= a wireless device other than a wireless device) from a wireless device adjacent to the wireless node. Consists of.

  FIG. 5 is a diagram showing the configuration of the transfer terminal candidate list. The transfer terminal candidate list FTCL includes a rank and a wireless device name. The rank and the wireless device name are associated with each other. The rank represents the rank with the largest number of received packets. The wireless device name includes IP addresses IPaddA, IPaddB, IPaddC,.

  FIG. 6 is a conceptual diagram of the transfer terminal list. The transfer terminal list FTL includes IP addresses. The IP address is made up of the IP address of the wireless device selected as the wireless device requesting the transfer of the packet PKT by the wireless device transferring the packet PKT.

  FIG. 7 is a diagram for explaining a method of creating the received packet statistics list 104. FIG. 8 is a diagram illustrating an example of the received packet statistics list 104.

  A case where the information creation unit 103 of the wireless device 1 creates the received packet statistics list 104 will be described. The information creation means 103 of the wireless device 1 receives the packet PKT transmitted from the wireless devices 2 to 14, and the source address, the source address of the received packet PKT, and the number of hops from the source wireless device to itself Is detected.

  For example, when receiving the packet PKT from the wireless device 2, the information creating unit 103 of the wireless device 1 detects IPadd2 as the source address and the source address, and detects “1” as the number of hops. Further, when the information creation means 103 of the wireless device 1 receives the packet PKT transmitted from the wireless device 7 via the wireless device 5, it detects IPadd7 as the source address, detects IPadd5 as the source address, “2” is detected as the number of hops. Further, when the information creation unit 103 of the wireless device 1 receives the packet PKT transmitted from the wireless device 10 via the wireless devices 6 and 8, it detects IPadd10 as the source address and detects IPadd8 as the source address. Then, “3” is detected as the number of hops.

  As described above, when the wireless device 1 receives the packet PKT from the wireless devices 2 to 14, the information creating unit 103 of the wireless device 1 receives the transmission source address, the transmission source address, and the transmission source wireless device of the received packet PKT. The number of hops up to itself is detected (see FIG. 7).

  Then, the information creation means 103 of the wireless device 1 detects the source address, the source address of the packet PKT received from the wireless devices 2 to 14 by the wireless device 1 and the number of hops from the source wireless device to itself. Based on the detected source address, source address, and the number of hops from the source wireless device to itself, the received packet statistics list 104-1 shown in FIG. 8 is created.

  The received packet statistics list 104-1 takes the source node (= wireless device 2 to wireless device 14) on the vertical axis and the wireless devices 2, 5, 7, and 8 adjacent to the wireless device 1 on the horizontal axis. The devices 2, 5, 7, and 8 have a configuration in which the number of hops (= for example, 1 to 5) is provided.

  Then, the information creation means 103 of the wireless device 1 is configured such that when the source address is IPPadd2, the source address is IPadd2, and the number of hops is “1”, the source node is the wireless device 2 and the adjacent wireless device “1” indicating the number of received packets is stored in an area where the number of hops of the square of which the device is the wireless device 2 is “1”.

  Further, the information creation means 103 of the wireless device 1 is configured such that when the source address is IPPadd2, the source address is IPadd3, and the hop count is “2”, the source node is the wireless device 2 and the adjacent wireless device “1” indicating the number of received packets is stored in the 2-hop area of the square where the device is the wireless device 3.

  Hereinafter, in the same manner, the information creation unit 103 of the wireless device 1 receives the packet PKT from the wireless devices 2 to 14 every time the wireless device 1 receives the packet PKT from the transmission source address, the transmission source address, and the transmission source wireless device. The number of hops up to 1 is detected, and the number of received packets in the corresponding area of the received packet statistics list 104-1 is incremented by “1”.

  The information creation unit 103 of the wireless device 1 increments the number of received packets in the corresponding area by “1” by the above-described method based on the packets received by the wireless device 1 from the wireless devices 2 to 14 within a certain period. The reception packet statistics list 104-1 is created.

  In the received packet statistics list 104-1, it is impossible if the source node and the adjacent wireless device are the same and the number of hops from the source node to the wireless device 1 is "2". The number of received packets in the corresponding area is “0”.

  Further, even when the source node is different from the adjacent wireless device and the hop count is “1”, the number of received packets in the corresponding area is also “0”.

  9 and 10 are diagrams showing another example of the received packet statistics list 104. FIG. The information creation means 103 of the wireless device 8 creates the received packet statistics list 104-2 in the wireless device 8 by the method described above, and the information creation means 103 of the wireless device 10 receives the reception by the wireless device 10 by the method described above. A packet statistics list 104-3 is created.

  Next, a method for selecting a transfer terminal in each wireless device will be described. FIG. 11 is a diagram for explaining a method of selecting a transfer terminal. FIG. 12 is a diagram illustrating an example of a transfer terminal candidate list. Furthermore, FIG. 13 is a diagram illustrating an example of a transfer terminal list. Note that regions REG1 to REG3 in FIG. 11 indicate the communication ranges of the wireless devices 1, 8, and 10, respectively.

  The wireless devices 1, 8, and 10 hold received packet statistics lists 104-1 to 104-3, respectively.

  When the packet PKT is flooded, the transmission / reception means 102 of the wireless device 1 generates a signal REQ and outputs the signal REQ to the creation means 105. Upon receiving the signal REQ from the transmission / reception unit 102, the creation unit 105 of the wireless device 1 refers to the received packet statistics list 104-1 and describes the wireless devices 2 to 5 described on the horizontal axis of the received packet statistics list 104-1. , 7 and 8, the total number of received packets in the area where the number of transfer hops is “2” is calculated.

  When the wireless device 1 receives a packet PKT from the source node via the wireless device 2, the number of packets that reach the wireless device 1 in two hops from the wireless devices 2 to 14 (= source node) are “0” and “0”, respectively. 5 ”,“ 2 ”,“ 6 ”,“ 0 ”,“ 7 ”,“ 1 ”,“ 0 ”,“ 0 ”,“ 0 ”,“ 0 ”,“ 0 ”,“ 0 ”( The creation unit 105 of the wireless device 1 calculates 0 + 5 + 2 + 6 + 0 + 7 + 1 + 0 + 0 + 0 + 0 + 0 + 0 = 21.

  Similarly, the creation unit 105 of the wireless device 1 is used when the wireless device 1 receives the packet PKT from the wireless devices 2 to 14 (= source node) via the wireless devices 3 to 5, 7, and 8 via two hops. The numbers of received packets are calculated as “13”, “23”, “61”, “56”, and “102”, respectively.

  Then, the creation unit 105 of the wireless device 1 creates the transfer terminal candidate list FTCL-1 (see FIG. 12) by rearranging the wireless devices 2 to 5, 7, and 8 in the descending order of the calculated number of received packets.

  In this case, the number of received packets that the wireless device 1 receives via the wireless devices 2 to 5, 7, and 8 is 21, 13, 23, 61, 56, and 102, respectively. The creation means 105 of the device 1 is that the wireless device 8, the wireless device 5, the wireless device 7, the wireless device 4, the wireless device 2 and the wireless device 3 are first, second, third, fourth, fifth and A transfer terminal candidate list FTCL-1 in the sixth place is created.

  Then, the creation unit 105 of the wireless device 1 outputs the created transfer terminal candidate list FTCL-1 to the selection unit 106.

  When the selection means 106 of the wireless device 1 receives the transfer terminal list FTCL-1 from the creation means 105, the three wireless devices 8, 5, 7 from the first place to the third place of the received transfer terminal list FTCL-1 are received. And the transfer terminal list FTL-1 (see FIG. 13) including the IP addresses IPadd8, IPadd5, and IPadd7 of the selected three wireless devices 8, 5, and 7 is created. Then, the selection unit 106 of the wireless device 1 outputs the created transfer terminal list FTL-1 to the transmission / reception unit 102.

  As described above, the selection unit 106 of the wireless device 1 selects a predetermined number of transfer terminals in descending order from the transfer terminal candidate list FTCL-1.

  Upon receiving the transfer terminal list FTL-1 from the selection means 106, the transmission / reception means 102 of the wireless device 1 stores the received transfer terminal list FTL-1 in the header of the packet PKT, and stores the transfer terminal list FTL-1 The packet PKT is transmitted via the antenna 101.

  In this way, the source wireless device 1 selects a predetermined number of transfer terminals in descending order of the number of packets delivered to itself in two hops.

  Subsequently, a method of selecting a transfer terminal at the relay terminal of the packet PKT transmitted from the wireless device 1 will be described. FIG. 14 is a diagram showing another example of the transfer terminal candidate list FTCL. FIG. 15 is a diagram showing another example of the transfer terminal list FTL. In the following, a method for selecting a transfer terminal in the wireless device 8 will be described.

  The transmission / reception means 102 of the wireless device 8 receives the packet PKT transmitted from the wireless device 1, and refers to the header of the received packet PKT to determine whether or not the packet PKT includes the transfer terminal list FTL-1. To do.

  Then, when the packet PKT includes the transfer terminal list FTL-1, the transmission / reception means 102 of the wireless device 8 detects the transmission source address (= IPadd1) of the packet PKT, and sends the detected transmission source address IPadd1 to the creation means 105. At the same time, a signal REQ is generated and output to the generation means 105. Upon receiving the transmission source address IPadd1 and the signal REQ from the transmission / reception unit 102, the creation unit 105 of the wireless device 8 searches the vertical axis of the received packet statistics list 104-2 (see FIG. 9) based on the transmission source address IPadd1. The wireless device 1 whose IP address matches the source address IPadd1 is detected.

  Thereafter, the creation unit 105 of the wireless device 8 searches the horizontal axis of the received packet statistics list 104-2 and relays the packet PKT transmitted from the wireless device 1 to the wireless device 8, wireless devices 1, 5 to 7, 9 , 10 are detected. Then, the creation unit 105 of the wireless device 8 receives “0”, “10”, “0”, “0”, which is the number of received packets of the second hop in each of the detected wireless devices 1, 5 to 7, 9, 10. 12 ”,“ 2 ”, and“ 1 ”are detected.

  Then, the creation unit 105 of the wireless device 8 rearranges the wireless devices 1, 5 to 7, 9, and 10 in ascending order of the number of received packets to create the transfer terminal candidate list FTCL-2 (see FIG. 14). Note that the creation unit 105 of the wireless device 8 has the smallest number of received packets “0” in the 2-hop area of the wireless device 1, but the wireless device 1 transmits the packet PKT to the wireless device 8 in two hops. Since there is no possibility, the wireless terminal 1 is excluded and the transfer terminal candidate list FTCL-2 is created.

  Then, the creation unit 105 of the wireless device 8 outputs the created transfer terminal candidate list FTCL-2 to the selection unit 106.

  Upon receiving the transfer terminal candidate list FTCL-2 from the creation means 105, the selection unit 106 of the radio apparatus 8 receives the three radio apparatuses 6 and 10 from the first to third ranks in the received transfer terminal candidate list FTCL-2. , 9 and the transfer terminal list FTL-2 (see FIG. 15) including the IP addresses IPadd6, IPadd10, and IPadd9 of the three selected wireless devices 6, 10, 9 is created. Then, the selection unit 106 of the wireless device 8 outputs the created transfer terminal list FTL-2 to the transmission / reception unit 102.

  As described above, the selection unit 106 of the wireless device 8 that is a relay terminal selects a predetermined number of transfer terminals from the transfer terminal candidate list FTCL-2 in descending order.

  When the transmission / reception means 102 of the wireless device 8 receives the transfer terminal list FTL-2 from the selection means 106, the transfer terminal list FTL-1 included in the packet PKT received from the wireless device 1 is changed to the transfer terminal list FTL-2. The packet PKT storing the rewritten and transfer terminal list FTL-2 is transferred via the antenna 101.

  As described above, the wireless device 8 serving as a relay terminal selects the wireless devices 5 to 7, 9, and 10 that directly transfer the packet PKT from the wireless device 8 that has transmitted the packet PKT to itself, and the transfer hop count is 2 The transfer apparatus list FTL-2 is created by rearranging the selected radio apparatuses 5 to 7, 9, and 10 in ascending order of the number of transfer packets, with the radio apparatus having zero hop packet as the highest rank.

  The other wireless devices 2 to 5 and 7 existing within the communication range of the wireless device 1 also create a transfer terminal list in the same manner, and update the transfer terminal list included in the packet PKT with the created transfer terminal list. Forward the packet.

  Finally, a method for selecting a transfer terminal at the relay terminal for the packet PKT transferred from the wireless device 8 will be described. FIG. 16 is a diagram illustrating still another example of the transfer terminal candidate list. FIG. 17 is a diagram showing still another example of the transfer terminal list. In the following, a method for selecting a transfer terminal in the wireless device 10 will be described.

  The transmission / reception means 102 of the wireless device 10 receives the packet PKT transmitted from the wireless device 8 and refers to the header of the received packet PKT to determine whether or not the packet PKT includes the transfer terminal list FTL-2. To do.

  Then, when the packet PKT includes the transfer terminal list FTL-2, the transmission / reception means 102 of the wireless device 10 detects the source address (= IPadd8) of the packet PKT, and sends the detected source address IPadd8 to the creation means 105. At the same time, a signal REQ is generated and output to the generation means 105. Upon receiving the transmission source address IPadd8 and the signal REQ from the transmission / reception unit 102, the creation unit 105 of the wireless device 10 searches the vertical axis of the received packet statistics list 104-3 (see FIG. 10) based on the transmission source address IPadd8. The wireless device 8 whose IP address matches the source address IPadd8 is detected.

  Thereafter, the creation unit 105 of the wireless device 10 searches the horizontal axis of the received packet statistics list 104-3 and relays the packet PKT transmitted from the wireless device 8 to the wireless device 10, and the wireless devices 6, 8, 9, 11 ˜13 are detected. Then, the creation unit 105 of the wireless device 10 receives “10”, “0”, “10”, “10”, which is the number of received packets of the second hop in each of the detected wireless devices 6, 8, 9, 11 to 13. 0 ”,“ 0 ”,“ 0 ”are detected.

  Then, the creation unit 105 of the wireless device 10 rearranges the wireless devices 6, 8, 9, 11 to 13 in ascending order of the number of received packets, and creates the transfer terminal candidate list FTCL-3 (see FIG. 16). The creation unit 105 of the wireless device 10 has the smallest number of received packets “0” in the 2-hop area of the wireless device 8, but the wireless device 8 transmits the packet PKT to the wireless device 10 in two hops. Since there is no possibility, the wireless terminal 8 is excluded and the transfer terminal candidate list FTCL-3 is created.

  Then, the creation unit 105 of the wireless device 8 outputs the created transfer terminal candidate list FTCL-3 to the selection unit 106.

  When receiving the transfer terminal candidate list FTCL-3 from the creation means 105, the selection unit 106 of the radio apparatus 10 receives the three radio apparatuses 11, 12 from the first to the third place in the received transfer terminal candidate list FTCL-3. , 13 and the transfer terminal list FTL-3 (see FIG. 15) including the IP addresses IPadd11, IPadd12, and IPadd13 of the three selected wireless devices 11, 12, and 13 is created. Then, the selection unit 106 of the wireless device 10 outputs the created transfer terminal list FTL-3 to the transmission / reception unit 102.

  In this way, the wireless device 10 that is a relay terminal selects a predetermined number of transfer terminals in the descending order from the transfer terminal candidate list FTCL-3.

  When the transmission / reception means 102 of the wireless device 10 receives the transfer terminal list FTL-3 from the selection means 106, the transmission terminal list FTL-2 included in the packet PKT received from the wireless device 8 is transferred to the transfer terminal list FTL-3. The packet PKT storing the rewritten and transfer terminal list FTL-3 is transmitted via the antenna 101.

  In this way, the wireless device 10 that is a relay terminal selects the wireless devices 6, 8, 9, and 11 to 13 that directly transfer the packet PKT from the wireless device 10 that has transmitted the packet PKT to itself, and the number of transfer hops. , The wireless device with the number of packets that are the second hop is zero, and the selected wireless devices 6, 8, 9, 11 to 13 are rearranged in ascending order of the number of transfer packets, and the transfer terminal list FTL-3 Create

  Similarly to the wireless device 10, the wireless devices 6 and 9 that have received the packet PKT relayed by the wireless device 8 also select a transfer terminal and receive a packet PKT including a transfer terminal list including the selected transfer terminals. Forward.

  As described above, the wireless device 1 that is the transmission source selects a transfer terminal that requests transfer of the packet PKT transmitted by itself from the wireless devices that deliver the packet PKT to itself in the second hop. In addition, the wireless devices 8 and 10 that are transfer terminals other than the transmission source self-assign a wireless device that has a relatively low rate of transferring the packet PKT from the wireless device that directly transmitted the packet PKT at the second hop to itself. Is selected as a transfer terminal that requests transfer of the packet PKT transmitted.

  As described above, in the present invention, the source wireless device and the relay terminal select the transfer terminal that requests the transfer of the packet PKT transmitted by itself by paying attention to the “second hop” as the number of transfer hops. This is because it is difficult to specify the number of transfers required to reach the receiving terminal for a packet transferred three or more times in flooding. That is, since the packet PKT may be transferred many times within the communication ranges REG1 to REG3 of the wireless devices 1, 8, and 10, transfer required until the packet transferred three or more times reaches the receiving terminal. This is because it is difficult to specify the number of times.

  When the source wireless device and the relay terminal select the transfer terminal by the method described above, the packet PKT transmitted from the wireless device 1 exists outside the communication range REG1 of the wireless device 1, as shown in FIG. Wireless devices 5, 7, 8, wireless devices 6, 9, 10 existing outside the communication range REG 2 of the wireless device 8 and wireless devices 11-13 existing outside the communication range REG 3 of the wireless device 10 are sequentially transferred to the wireless network It is delivered to all the wireless devices 2 to 14 in 100.

  Therefore, according to the present invention, packets can be transferred efficiently.

  FIG. 18 is a flowchart for explaining a packet flooding method in the wireless network 100 shown in FIG. When a series of operations is started, the transmission source wireless device selects a transfer terminal based on the received packet statistics list 104, generates a packet PKT including a transfer terminal list including the selected transfer terminal, and transmits the packet PKT. (Step S1).

  Then, the transfer terminal receives the packet PKT (step S2), and determines whether or not the transfer terminal list is included in the packet PKT based on the received packet PKT (step S3).

  When it is determined in step S3 that the transfer terminal list is not included in the packet PKT, the transfer terminal transfers the packet (step S4).

  On the other hand, when it is determined in step S3 that the transfer terminal list is included in the packet PKT, the transfer terminal further determines whether or not the transfer terminal list is included in the transfer terminal list (step S5).

  When it is determined in step S5 that the transfer terminal is not included in the transfer terminal list, the transfer terminal discards the packet PKT (step S6). That is, the transfer terminal does not transfer the packet PKT.

  On the other hand, when it is determined in step S5 that the transfer terminal is included in the transfer terminal list, the transfer terminal creates a transfer terminal list based on the received packet statistics list 104, and packet PKT is generated by the created transfer terminal list. And the packet PKT is transferred (step S7).

  And after any of step S4, step S6, and step S7, a series of operation | movement is complete | finished.

  As described above, when the packet PKT does not include the transfer terminal list, the transfer terminal transfers the received packet PKT (see “NO” in step S3 and step S4), and thus the transfer terminal list is included in the packet PKT. If not, flooding is performed in the wireless network 100.

  Also, the transfer terminal transfers the received packet PKT if it is included in the transfer terminal list (see “YES” in step S5 and step S7), and transfers the packet if it is not included in the transfer terminal list. Therefore, some wireless devices in the wireless network 100 transfer the packet PKT (see “NO” in step S5 and step S6). As a result, the packet PKT can be transferred more efficiently than when all the wireless devices in the wireless network 100 transfer the packet PKT.

  FIG. 19 is a flowchart for explaining the detailed operation of step S1 shown in FIG. When a series of operations is started, the source wireless device creates the received packet statistics list 104 (step S11). Then, based on the received packet statistics list 104, the source wireless device selects the wireless device that has transferred the packet to itself at the second hop (step S12).

  Thereafter, the transmission source wireless device creates a transfer terminal candidate list in which the selected wireless devices are rearranged in descending order of the number of packet transfers (step S13). Then, the source wireless device selects a smaller number of terminals as a transfer terminal among the predetermined number and the number of adjacent terminals sequentially selected from the top of the created transfer terminal candidate list (step S14).

  Thereafter, the transmission source wireless device creates a transfer terminal list including the selected transfer terminals (step S15).

  Then, the source wireless device creates and transmits a packet including the transfer terminal list (step S16). Then, a series of operation | movement transfers to step S2 shown in FIG.

  FIG. 20 is a flowchart for explaining the detailed operation of step S7 shown in FIG. After “YES” in step S5 shown in FIG. 18, the relay terminal selects a wireless device that transfers the packet PKT from the transmission source based on the reception packet statistics list 104 created in advance (step S71). .

  Then, the relay terminal rearranges the selected wireless devices in ascending order of the number of transfer packets with the wireless device having the number of packets with the second hop count being zero as the highest order, and creates a transfer terminal candidate list. (Step S72).

  Thereafter, the transfer terminal selects a smaller number of terminals as a transfer terminal among the predetermined number and the number of adjacent terminals selected in order from the top of the transfer terminal candidate list (step S73).

  Then, the relay terminal creates a transfer terminal list including the selected transfer terminals (step S74). Thereafter, the relay terminal updates the transfer terminal list included in the packet with the created transfer terminal list and transmits the packet (step S75). Then, the series of operations proceeds to “END” shown in FIG.

  Although not specified in the flowchart shown in FIG. 20, the relay terminal executes the step of creating the received packet statistics list 104 in advance before executing the operation of selecting the transfer terminal.

  Furthermore, in the present invention, the selection of the transfer terminal is executed by a computer. FIG. 21 is a schematic diagram illustrating the configuration of a computer. The computer 200 includes a CPU (Central Processing Unit) 201, a ROM (Read Only Memory) 202, a RAM (Randum Access Memory) 203, and a bus BS.

  The CPU 201, the ROM 202, and the RAM 203 are connected to each other via the bus BS. The ROM 202 stores the received packet statistics list 104, a program consisting of the flowchart shown in FIG. 19, and a program consisting of the flowchart shown in FIG. The RAM 203 functions as a work memory.

  The CPU 201 reads out and executes each program stored in the ROM 202, and executes selection of a transfer terminal in the transmission source radio apparatus or the relay terminal by the above-described method based on the received packet statistics list stored in the ROM 202. Therefore, the CPU 201 constitutes the creating unit 105 and the selecting unit 106 shown in FIG.

  Thus, the ROM 202 stores a program that is read and executed by the CPU 201, and thus constitutes a computer (CPU) -readable recording medium.

  In vehicle-to-vehicle communication, it is assumed that a wireless device frequently enters the wireless network 100 or leaves the wireless network 100 frequently.

  In order to deal with such a situation, each of the wireless devices 1 to 14 creates a plurality of received packet statistics lists 104 by shifting the creation time, and clears one received packet statistics list at regular intervals. The other received packet statistics list is used.

  FIG. 22 is a diagram for explaining a method of using a plurality of received packet statistics lists. Each wireless device 1-14 creates a received packet statistics list 104A, and creates a received packet statistics list 104B one second after the use of the created received packet statistics list 104A is started.

  When the wireless devices 1 to 14 finish using the received packet statistics list 104A, the wireless devices 1 to 14 delete the received packet statistics list 104A and select a transfer terminal using the received packet statistics list 104B.

  Thereafter, each of the wireless devices 1 to 14 creates the reception packet statistics list 104C one second after starting to use the reception packet statistics list 104B, and when the use of the reception packet statistics list 104B is finished, the reception packet statistics list 104B And the forwarding terminal is selected using the received packet statistics list 104C.

  Each of the wireless devices 1 to 14 subsequently updates the received packet statistics list 104 in the same manner, and selects a transfer terminal using the latest received packet statistics list 104.

  The reason why the received packet statistics lists 104B and 104C are created one second after the use of the received packet statistics lists 104A and 104B is started is as follows. When each of the wireless devices 1 to 14 generates a packet PKT every 100 milliseconds, it can grasp the status of an adjacent terminal in about 1 second (about 10 packets), and can create a received packet statistics list 104. Because.

  Therefore, the time interval for creating the reception packet statistics list 104 is determined according to the generation interval of the packet PKT generated by each wireless device 1-14. That is, the time interval for creating the reception packet statistics list 104 is set to a time interval for receiving the number of packets that each of the wireless devices 1 to 14 can create the reception packet statistics list 104.

  FIG. 23 is a diagram illustrating the relationship between the packet loss rate and the packet generation interval. In FIG. 23, the vertical axis represents the packet loss rate, and the horizontal axis represents the packet generation interval. Note that the relationship between the packet loss rate and the packet generation interval shown in FIG. 23 is an experimental result when the flooding method based on the duplicate packet check method described in Non-Patent Document 2 is used.

  The packet loss rate increases as the packet generation interval becomes shorter. Further, the packet loss rate increases as the number of wireless devices constituting the wireless network increases. The packet loss rate is higher than 80% when the number of wireless devices is 30 or more and the packet generation interval is shortened to 50 msec and 20 msec.

  FIG. 24 is a diagram showing a comparison between the conventional flooding method and the flooding method according to the present invention in the relationship between the packet loss rate and the packet generation interval.

  In FIG. 24, the vertical axis represents the packet loss rate, and the horizontal axis represents the packet generation interval. The relationship between the packet loss rate and the packet generation interval shown in FIG. 24 is an experimental result when the number of wireless devices is 50.

  In the conventional flooding method, the packet loss rate greatly exceeds 70% when the packet generation interval is 100 msec or less. However, in the flooding method according to the present invention, the packet loss rate is 50 msec in the packet generation interval. Is lower than 50%.

  Therefore, it was experimentally proved that the flooding method according to the present invention is more effective than the conventional flooding method.

  FIG. 25 is a schematic diagram showing packet transfer. Each of the wireless devices 1 to 14 is actually composed of a plurality of modules that perform communication control in accordance with an ARPA (Advanced Research Projects Agency) Internet hierarchical structure. That is, each of the wireless devices 1 to 14 includes a wireless interface module 110, a MAC module 111, an LLC module 112, an IP module 113, and an upper layer module 114.

  The wireless interface module 110 belongs to the physical layer, modulates / demodulates a transmission signal or a reception signal according to a predetermined rule, and transmits / receives a signal via the antenna 101.

  The MAC module 111 belongs to the MAC layer, executes the MAC protocol, and executes various functions described below. That is, the MAC module 111 broadcasts the packet via the wireless interface module 110. The MAC module 111 performs retransmission control of data (packets).

  The LLC module 112 belongs to the data link layer and executes the LLC protocol to connect and release a link with an adjacent wireless device.

  The IP module 113 belongs to the Internet layer and generates an IP packet. The IP packet includes an IP header and an IP data portion for storing a packet of a higher protocol. When receiving data from the upper layer module 114, the IP module 113 stores the received data in the IP data portion and generates an IP packet.

  The upper layer module 114 is composed of a TCP module or the like belonging to the transport layer or higher.

  A packet transfer mode according to the above-described method will be described. The wireless interface module 110 of the wireless device 8 receives the packet PKT transmitted from the wireless device 1 via the antenna 101, and transmits the received packet PKT to the IP module 113 via the MAC module 111 and the LLC module 112. .

  The IP module 113 of the wireless device 8 receives the packet PKT, detects the IP address IPaddress1 of the wireless device 1 with reference to the header of the received packet PKT, and the transmission source of the packet PKT is the wireless device 1 Detect that. Further, the IP module 113 of the wireless device 8 determines whether or not the transfer terminal list FTL-1 is included in the packet PKT. When the transfer terminal list FTL-1 is not included in the packet PKT, the received packet PKT is determined. Are transferred via the LLAC module 112, the MAC module 111, and the wireless interface 110.

  When the transfer terminal list FTL-1 is included in the packet PKT, the IP module 113 of the wireless device 8 determines whether or not the IP address IPadd8 of the wireless device 8 is included in the transfer terminal list FTL-1. When the IP address IPadd8 of the wireless device 8 is not included in the transfer terminal list FTL-1, the received packet PKT is discarded.

  On the other hand, when the IP module 113 of the wireless device 8 determines that the IP address IPadd8 of the wireless device 8 is included in the transfer terminal list FTL-1, the IP module 113 of the wireless device 8 described above is based on the received packet statistics list 104-2. Then, the transfer terminal list FTL-2 is created, the transfer terminal list FTL-1 is updated with the created transfer terminal list FTL-2, and the packet PKT including the transfer terminal list FTL-2 is transferred to the LLC module 112, MAC Transfer is performed via the module 111 and the wireless interface module 110.

  The wireless device 10 receives the packet PKT transferred by the wireless device 8 and transfers the received packet PKT in the same manner as the wireless device 8.

  The wireless devices 1 to 7, 9, and 11 to 14 also transfer the packet PKT in the same manner as the wireless devices 8 and 10.

  Thus, in the present invention, the packet PKT is transferred via the Internet layer to which the IP module 113 belongs.

  FIG. 26 is a diagram showing a conversion table. The conversion table CNVT includes MAC addresses MACaddress1 to MACaddress14 and IP addresses IPaddress1 to IPaddress14. The MAC addresses MACaddress1 to MACaddress14 are associated with the IP addresses IPaddress1 to IPaddress14, respectively.

  Each wireless device 1-14 exchanges packets including its own IP address and MAC address to obtain the IP address and MAC address of the other wireless device, and creates a conversion table CNVT. The converted table CNVT is held.

  FIG. 27 is a schematic diagram showing another transfer of a packet. A packet transfer mode according to the above-described method will be described.

  The wireless interface module 110 of the wireless device 8 receives the packet PKT transmitted from the wireless device 1 via the antenna 101, and transmits the received packet PKT to the MAC module 111.

  The MAC module 111 of the wireless device 8 receives the packet PKT, detects the MAC address MACaddress1 of the wireless device 1 with reference to the MAC header of the received packet PKT, and the transmission source of the packet PKT is the wireless device 1. Detect something. Also, the MAC module 111 of the wireless device 8 determines whether or not the transfer terminal list FTL-1 is included in the packet PKT, and when the transfer terminal list FTL-1 is not included in the packet PKT, the received packet PKT Are transferred via the wireless interface 110.

  When the transfer terminal list FTL-1 is included in the packet PKT, the MAC module 111 of the wireless device 8 determines whether or not the IP address IPadd8 of the wireless device 8 is included in the transfer terminal list FTL-1. When the IP address IPadd8 of the wireless device 8 is not included in the transfer terminal list FTL-1, the received packet PKT is discarded.

  On the other hand, if the MAC module 111 of the wireless device 8 determines that the IP address IPadd8 of the wireless device 8 is included in the transfer terminal list FTL-1, the MAC module 111 of the wireless device 8 is based on the received packet statistics list 104-2 held above. By the method described above, the transfer terminal is selected, the MAC address of the selected transfer terminal is converted to an IP address with reference to the conversion table CNVT, and the IP address of the transfer terminal is acquired. Then, the MAC module 111 of the wireless device creates a transfer terminal list FTL-2 composed of the acquired IP address, updates the transfer terminal list FTL-1 with the created transfer terminal list FTL-2, and transfers the transfer terminal list. The packet PKT including FTL-2 is transferred via the wireless interface module 110.

  The wireless device 10 receives the packet PKT transferred by the wireless device 8 and transfers the received packet PKT in the same manner as the wireless device 8.

  The wireless devices 1 to 7, 9, and 11 to 14 also transfer the packet PKT in the same manner as the wireless devices 8 and 10.

  Thus, in the present invention, the packet PKT is transferred via the MAC layer to which the MAC module 111 belongs. Therefore, the packet PKT can be transferred at high speed.

  In the above description, it has been described that the relay terminal selects a wireless device with a small number of packets whose transfer hop count is the second hop as a transfer terminal that requests transfer of the packet PKT. However, the present invention is not limited to this. In general, the relay terminal selects, as a transfer terminal, a radio apparatus having a relatively low rate of transferring a packet from the radio apparatus that has directly transmitted a packet to itself in the second hop.

  In the above description, the wireless devices 1 to 14 are described as being mounted on a vehicle. However, in the present invention, the wireless devices 1 to 14 are not limited to this, and are generally used for bicycles, motorcycles, and the like. As long as it is mounted on a moving body including

  Furthermore, the wireless devices 1 to 14 may be mounted on sensors constituting the sensor network, or may be mounted on devices used in an indoor environment.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

  The present invention is applied to a wireless network capable of efficiently transferring packets. The present invention is also applied to a wireless device used in a wireless network capable of efficiently transferring packets. Furthermore, the present invention is applied to a program for causing a computer to execute selection of a transfer terminal in a wireless network capable of efficient packet transfer. Furthermore, the present invention is applied to a computer-readable recording medium in which a program for causing a computer to execute selection of a transfer terminal in a wireless network capable of efficient packet transfer is recorded.

1 is a schematic diagram of a wireless network according to an embodiment of the present invention. It is a schematic block diagram which shows the structure of the radio | wireless apparatus shown in FIG. It is a block diagram of a packet. FIG. 3 is a diagram showing a configuration of a received packet statistics list shown in FIG. 2. It is a figure which shows the structure of a transfer terminal candidate list. It is a conceptual diagram of a transfer terminal list. It is a figure for demonstrating the preparation method of a reception packet statistics list | wrist. It is a figure which shows the example of a reception packet statistics list | wrist. It is a figure which shows the other example of a reception packet statistics list | wrist. It is a figure which shows the other example of a reception packet statistics list | wrist. It is a figure for demonstrating the selection method of a transfer terminal. It is a figure which shows the example of a transfer terminal candidate list. It is a figure which shows the example of a transfer terminal list. It is a figure which shows the other example of a transfer terminal candidate list. It is a figure which shows the other example of the transfer terminal list | wrist FTL. It is a figure which shows the further another example of a transfer terminal candidate list. It is a figure which shows the further another example of a transfer terminal list | wrist. 2 is a flowchart for explaining a packet flooding method in the wireless network shown in FIG. 1. It is a flowchart for demonstrating the detailed operation | movement of step S1 shown in FIG. It is a flowchart for demonstrating the detailed operation | movement of step S7 shown in FIG. It is the schematic which shows the structure of a computer. It is a figure for demonstrating the usage method of a some reception packet statistics list | wrist. It is a figure which shows the relationship between a packet loss rate and a packet production interval. It is a figure which shows the comparison with the flooding method by the conventional flooding method and this invention in the relationship between a packet loss rate and a packet production | generation space | interval. It is a schematic diagram which shows transfer of a packet. It is a figure which shows a conversion table. It is a schematic diagram which shows the other transfer of a packet.

Explanation of symbols

  1-14 wireless device, 100 wireless network, 101 antenna, 102 transmission / reception means, 103 information creation means, 104, 104-1 to 104-3, 104A, 104B, 104C received packet statistics list, 105 creation means, 106 selection means, 110 wireless interface module, 111 MAC module, 112 LLC module, 113 IP module, 114 upper layer module, 201 CPU, 202 ROM, 203 RAM.

Claims (9)

A wireless network established autonomously and performing wireless communication between a transmission source and a transmission destination,
A wireless device that transfers a packet transmitted by itself to a wireless device existing outside the communication range at the second hop is selected as a transfer terminal from among the wireless devices existing within the communication range of the device, and the selected transfer is performed. A first wireless device that generates and transmits a packet with a first transfer terminal list that is a list of terminals;
When a packet including the first wireless device as a transmission source is received, the received packet includes a transfer terminal list, and when the packet is included in the transfer terminal list, the wireless device existing within its communication range A wireless device that transmits a packet from the wireless device that directly transmitted the packet to itself in a second hop is selected as a transfer terminal, and the selected transfer terminal is a list of the selected transfer terminals. A wireless network comprising n second wireless devices (n is a positive integer) that transmits the packet by adding two forwarding terminal lists to the packet instead of the forwarding terminal list included in the packet.   When the n second radio apparatuses receive the packet from the first radio apparatus, the n second radio apparatuses add the second transfer terminal list to the packet instead of the first transfer terminal list. The wireless network of claim 1, wherein the wireless network transmits packets. The first wireless device maintains a first received packet statistics list indicating a statistical distribution of the number of hops of a packet delivered to itself from an arbitrary wireless device, and is based on the first received packet statistics list To select the transfer terminals constituting the first transfer terminal list,
Each of the n second wireless devices holds a second received packet statistics list indicating a statistical distribution of the number of hops of packets delivered from any wireless device to the second received wireless devices. The wireless network according to claim 1 or 2, wherein a transfer terminal constituting the second transfer terminal list is selected based on a packet statistics list. Based on the first received packet statistics list, the first wireless device forwards a packet transmitted from the arbitrary wireless device to itself at the second hop (j is a positive integer) radios A device is selected, a first transfer terminal candidate list is created in which the selected j wireless devices are rearranged in descending order of the number of packets transferred to the device, and the first transfer terminal candidate list is created. Select the transfer terminals constituting the first transfer terminal list in order from the top,
Each of the n second wireless devices forwards the packet from the wireless device that directly transmitted the packet to itself based on the second received packet statistics list, where k is a positive integer. ) Select the number of wireless devices, and arrange the selected k number of wireless devices in ascending order of the number of packets, with the wireless device having the number of transfer hops of the second hop being zero as the highest order. A second transfer terminal candidate list composed of the rearranged k wireless devices is created, and the second transfer terminal list is configured in order from the top of the created second transfer terminal candidate list. The wireless network according to claim 3, wherein a terminal is selected. The first wireless device periodically updates the first received packet statistics list;
The wireless network according to claim 4, wherein each of the n second wireless devices periodically updates the second received packet statistics list. A wireless device that is autonomously established and forms a wireless network in which wireless communication is performed between a transmission source and a transmission destination,
A wireless device comprising any one of the first wireless device according to any one of claims 1 to 5 and the n second wireless devices. A program for causing a computer to execute selection of a transfer terminal that requests transfer of a packet in a wireless device that is autonomously established and used in a wireless network in which wireless communication is performed between a transmission source and a transmission destination,
A first step of creating a received packet statistics list indicating a statistical distribution of the number of hops of a packet delivered to the wireless device from an arbitrary wireless device;
The selecting means selects i (i is a positive integer) number of wireless devices that transfer a packet from an arbitrary wireless device to the wireless device in the second hop based on the received packet statistics list. Steps,
A third step in which the creation means creates a transfer terminal candidate list in which the selected i wireless devices are rearranged in descending order of the number of packet transfers;
A program for causing the selection unit to cause a computer to execute a fourth step of selecting a wireless device that constitutes a transfer terminal in order from the top of the created first transfer terminal candidate list. A program for causing a computer to execute selection of a transfer terminal that requests transfer of a packet in a wireless device that is autonomously established and used in a wireless network in which wireless communication is performed between a transmission source and a transmission destination,
A first step of creating a received packet statistics list indicating a statistical distribution of the number of hops of a packet delivered to the wireless device from an arbitrary wireless device;
A second step of selecting k (k is a positive integer) number of wireless devices that transfer a packet from the wireless device that has directly transmitted the packet to itself based on the received packet statistics list; When,
The creation means rearranges the selected k radio devices in ascending order of the number of packets, with the radio device having the number of packets with the second hop count being zero as the highest rank, A third step of creating a second transfer terminal candidate list consisting of the replaced k wireless devices;
A program for causing the computer to execute a fourth step in which the selecting means selects transfer terminals constituting the second transfer terminal list in order from the top of the created second transfer terminal candidate list.   A computer-readable recording medium on which the program according to claim 7 or 8 is recorded.

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