JP2010157838A - Communication system including ad hoc network, mobile communication equipment for communication system, and communication method in communication system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a communication system including an ad hoc network for enabling the ad hoc network to efficiently select a gateway for connecting a fixed external network. <P>SOLUTION: When the ad hoc network 1 is composed of a plurality of mobile routers MR, the mobile routers to be a gateway GW to an external network 2 transmit and receive a gateway notification packet including a gateway priority and radio link information among mobile routers. Thus, each mobile router selects and changes a gateway by continuing and canceling the gateway or determining to be a new gateway, and selects and change the gateway by autonomous distributed control of each mobile router without requiring a special node. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a communication system including an ad hoc network composed of a plurality of mobile communication devices.

  Conventionally, in NEMO (Network Mobility) in IETF (Internet Engineering Task Force), a method of performing location registration at the time of handover of a mobile network by placing a mobile router in the mobile network has been defined (for example, the following non-patent document) Reference 1). Further, IETF MONEMO (MANET (Mobile Ad-hoc Network) for NEMO) discloses wireless multi-hop communication between mobile routers when a plurality of NEMO-compatible mobile routers form an ad hoc network (for example, the following) Non-patent documents 2 and 3).

V. Devarapalli, et al., "Network Mobility (NEMO) Basic Support Protocol", RFC (Request for Comment) 3963, pp. 1-33, January 2005 P. Thubert, et al., "Nested Nemo Tree Discovery draft-thubert-tree-discovery-07.txt", IETF (Internet Engineering Task Force), pp. 1-28, August 1, 2008 P. Thubert, et al., "Network In Node Advertisement draft-thubert-nina-02.txt", IETF, pp. 1-32, February 4, 2008

  However, for example, Non-Patent Document 1 discloses connection control of a mobile router serving as a gateway to the network, and Non-Patent Documents 2 and 3 described above each form an ad hoc network with a mobile router serving as a gateway. It disclosed the route control of the mobile router, but did not disclose the gateway selection method.

  The present invention has been made in view of the above, and an ad hoc network that performs multi-hop communication by linking a plurality of mobile communication devices including a mobile router of a small mobile network or a single mobile IP terminal An object of the present invention is to provide a communication system including an ad hoc network that can efficiently select a gateway for the ad hoc network to connect to the fixed network when connecting to the fixed network.

  The present invention includes a first network that is a mobile network in which a plurality of mobile communication devices constitute an ad hoc network, and a second network that is a fixed network connected to the first network so as to be capable of wireless communication. A communication system including an ad hoc network in which the mobile communication device having a predetermined number of gateways or less for the first network to communicate with the second network serves as a gateway and communicates with the second network. In the case where each of the plurality of mobile communication devices can be connected to the second network via a radio link, or the radio link information includes the loss rate, delay, received signal strength, and bandwidth of the radio link with the second network. If at least one of the connections can be connected with a quality higher than the specified level, it becomes a gateway. In order to notify that it is a gateway, a first gateway notification packet including at least one of its IP address and at least one of the gateway priority and at least one of the radio link information with the second network is first Broadcast or multicast to each mobile communication device in the network, and the gateway notification packet sent from the mobile communication device in the first network is broadcast or multicast to other mobile communication devices in the first network. However, the duplicated gateway notification packet is discarded, the gateway notification packet is transmitted to all transferable mobile communication devices, and if the mobile communication device is in a state of being a gateway, the first network Inside the gateway (B) Ranking itself within the first network according to the comparison result of the gateway priority of the gateway notification packet or the radio link information from the other mobile communication device that is a, and within the number of gateways In the communication system including the ad hoc network, the gateway control means includes a gateway control unit that continues the gateway in the case of the rank of the above, and cancels the gateway in the case of the rank exceeding the set number of gateways. .

  In the present invention, the selection and change of a mobile communication device as a gateway to an external network is realized by autonomous distributed control of each mobile communication device composed of a mobile router or the like constituting an ad hoc network without requiring a special node. it can.

Embodiment 1 FIG.
Embodiments of a communication system including an ad hoc network according to the present invention, a mobile communication device for the communication system, and a communication method for the communication system will be described below in detail with reference to the drawings. The present invention is not limited to this embodiment, and includes all possible combinations of functions and processes added as modifications.

  FIG. 1 is a diagram showing an example of a configuration of a communication system including an ad hoc network according to an embodiment of the present invention. The communication system of FIG. 1 includes an ad hoc network 1 that is a mobile network and an external network 2 that is a fixed network.

  The ad hoc network 1 includes mobile networks 1A, 1B, 1C, and 1D, and the mobile networks 1A to 1D constitute an ad hoc network connected by a wired link or a wireless link.

  The mobile networks 1A to 1D include mobile routers (MR) 11 to 14, respectively, and mobile network prefixes (MNP) 21 to 24 managed by mobile network prefixes (MNP) 21 to 24 under these MRs. .

  The external network 2 (for example, the Internet or a core network) is a fixed network and is an opposite node of the access routers (AR) 41 to 43, the HA (home agent) 51 and the terminals MN31 to 34 in the ad hoc network 1. A CN (Correspond Node) 6 is provided.

  The MR 11 of the mobile network 1A and the MR 13 of the mobile network 1C are connected to the AR 41, AR 42, and AR 43, respectively, by radio links.

  Specifically, such mobile networks 1A to 1D are installed in a mobile router for each of a plurality of trains, and move together. A mobile router is mounted on an automobile, a ship, an aircraft, etc. Use is assumed.

  FIG. 10 is a diagram showing an example of the configuration of each mobile router (MR) 11-14 shown in FIG. The MR includes one or more wired or wireless interfaces 70-m (m = 1, 2,... N), a packet control unit 71, and a packet transfer processing unit 72. The packet control unit 71 includes a route control unit 73 and a gateway control unit 74, and the packet transfer processing unit 72 includes a packet transfer unit 76 and a route control table 77, respectively.

  The path control unit 73 of the packet control unit 71 basically manages the communication path of normal data communication between the MNs in the mobile network under its control, but this point is not particularly related to the present invention. Is omitted. The gateway control unit 74 manages the wireless link information such as the priority of the gateway, which will be described later, or the loss rate, delay, received signal strength, and bandwidth of the wireless link with the second network, and the gateway notification in which such information is mounted. Radio link information such as the priority of the gateway in the received gateway notification packet or the loss rate, delay, received signal strength, and bandwidth of the radio link with the second network while flooding the packet (GWO: GateWay Option) For example, it compares its own information stored in a memory (not shown), and selects and changes a gateway.

The gateway control unit 74 broadcasts or multicasts a gateway notification packet (GWO), which is an extension of router advertisement (RA), to an adjacent node in the ad hoc network 1 because it is a gateway in the ad hoc network 1. To do. In the adjacent node that has received the gateway notification packet (GWO), the gateway control unit 74 checks the duplication, and further broadcasts or multicasts to the adjacent node, and repeats this, thereby repeating the gateway notification packet (GWO) in the ad hoc network 1. ) Is flooded.

  The GWO is flooded in the ad hoc network 1 and transmitted to all MRs. Each gateway control unit 74 of the MRs 11 to 14 obtains information on the gateway in the ad hoc network 1 from the GWO, becomes a gateway, and continues the gateway. , Make a decision to cancel.

  The packet transfer unit 76 of the packet transfer processing unit 72 has a packet transfer function that refers to the route control table 77 and distributes the packet transfer destination.

  It should be noted that various quality standards for radio link information, the number of gateways, and the like, which are necessary for determination processing described later, are stored in, for example, the above-described memory of the gateway control unit 74 in each MR.

  Further, the packet control unit 71 and the packet transfer processing unit 72 constitute a gateway control unit.

  Next, the message format will be described with reference to FIG. FIG. 11 is a diagram for explaining an example of the format of the gateway notification packet (GWO) described above. (A) shows the data structure, (b) shows the number of bits of each data (parameter) in (a), A table showing the values and contents is shown. This format defines a new format as a gateway notification packet (GWO) in an option format of router advertisement (RA).

  As the format type “Type”, a new unused value (for example, “210”) is defined. Option length “Length” in units of 8 octets, flag “I” (gateway bit) indicating whether the mobile router is operating, flag “H” indicating whether the mobile router is connected to the home network, battery operation Flag “B” indicating whether or not the GWO is fresh, “Sequence Number (sequence number)” transmitted by the gateway incremented by +1 for each transmission, and “GW Lifetime (GW) Lifetime) ”and“ GW Preference (gateway priority) ”which is the priority of the gateway.

  Furthermore, the gateway address IP address (or ID information) of the gateway notification packet transmission source "Gateway Address (gateway address)", indicating the quality cost of the wireless link between the gateway and the access router, control packets such as router advertisements or It has “Uniform Path Metric” in which radio link quality, delay, etc. such as user packet reception rate (loss rate) or reception signal level (reception signal strength) are defined, and “BandWidth” indicating the bandwidth of the radio link.

  Next, the entire process of selecting a gateway and changing a gateway, particularly in an ad hoc network of the communication system configured as shown in FIG. 1, will be described. FIG. 12 is a time table for explaining an example of an operation sequence at the time of gateway selection and gateway change between the mobile routers MR11 to MR14 of the ad hoc network 1 and the access routers AR41 and AR43 of the external network 2 in FIG.

  The number of gateways defined in advance in the ad hoc network 1 is, for example, “1”.

  First, when the radio link between MR11 and AR41 and the radio link between MR13 and AR43 are established, or when the link state is connectable with a predetermined quality or higher, MR11 and MR13 are respectively gateways (GW) in ad hoc network 1 (MR13 is GW first in FIG. 12), and gateway notification packets GWO (MR11) and GWO (MR13) each having an “I” bit indicating a gateway are transmitted.

  Note that the quality of the link state is, as will be described later, at least one of the radio link information including the loss rate, delay, received signal strength, and bandwidth of the radio link with the external network 2 is a predetermined quality or higher. It shows that. In addition, while the MR is a gateway, it transmits (floods) GWO periodically or when radio link information changes. When the gateway is canceled, the GWO is flooded without setting the “I” bit indicating the gateway, or the GWO is not flooded for the own MR. Also, all MRs transfer GWOs from other MRs to other MRs (all adjacent MRs excluding the transmission source) by incrementing a sequence number (Sequence Number). The duplicate GWO is discarded.

  Here, the priority of GWO (MR11) or the cost of radio link information is “medium”, and the priority of GWO (MR13) or the cost of radio link information is “low”. MR11 compares the cost of its own priority or the radio link information with the priority of the received GWO or the cost of the radio link information, and since it is higher, it continues the gateway. The MR 13 compares the cost of its own priority or the radio link information with the priority of the received GWO or the cost of the radio link information, and cancels the gateway because it is lower (non-GW).

  Furthermore, the MR 13 that has canceled the gateway does not transmit its own GWO at the next timing to transmit the GWO, or transmits the GWO without setting the “I” bit, thereby confirming that it is not the gateway. Notify other mobile routers (the gateway selection).

  Next, in the MR 13 which is not a gateway, the priority or the cost of the radio link information becomes “high”, and the priority or the cost of the radio link information becomes higher than the received GWO (MR 11). MR13 becomes a gateway (GW) newly, sets "I" bit, and transmits GWO (MR13) of the priority or the cost "high" of radio link information. The MR 11 cancels the GW by receiving the GW (MR 13) higher than its own priority or the cost of the radio link information (the gateway change).

  Next, the gateway selection operation in the communication system including the ad hoc network configured as described above will be described in detail with reference to FIGS. FIG. 13 is a flowchart showing the operation at the time of gateway selection and change in each MR.

(1) Gateway Selection First, the ad hoc network 1 when 1 is set as the number of gateways for connecting the ad hoc network 1 that is the first network to the external network 2 that is the second network by system setting. Will be described until the gateway selection is performed.

  FIG. 2 is a diagram illustrating how the gateway notification message GWO is flooded from the MR 11 and MR 13 which are gateways in the ad hoc network 1. In FIG. 2, when MR11 and AR41 and MR13 and AR43 are connected by a radio link, or one or more or all of radio link information including loss rate, delay, received signal strength, bandwidth, etc. of the radio link Information (hereinafter also simply referred to as wireless link information) and can be connected with a predetermined quality or higher (S1 in FIG. 13) [see the thick arrow in FIG. 2], MR11 and MR13 are each ad hoc autonomously. It becomes a gateway in the network 1 (S2 in FIG. 13). At this point, each of the mobile networks 1A to 1D in the ad hoc network 1 can be connected to the external network 2 via the gateways MR11 and MR13.

  MR11 and MR13 become the gateway in the ad hoc network 1, and thus flood the above-mentioned gateway notification packet (GWO) in the ad hoc network 1 (S3 in FIG. 13).

  In the example of FIG. 2, MR 11 transmits GWO (gateway address = MR 11 address) indicated by thin solid arrows in FIG. 2 to MR 12 and MR 14 adjacent to each other (which is one hop). Hereinafter, information included in a message (packet) is expressed in parentheses.

  MR12 which has received GWO (gateway address = MR11 address) from MR11 transmits GWO (gateway address = MR11 address) to MR13 as it is, if no GWO (gateway address = MR11 address) is received from adjacent MR13. To do.

  In addition, if MR14 that has received GWO (gateway address = MR11 address) from MR11 does not receive GWO (gateway address = MR11 address) from adjacent MR13, MR14 directly receives GWO (gateway address = MR11 address). (S4, S5 in FIG. 13).

  MR13 that has received GWO (gateway address = MR11 address) from MR12 and GWO (gateway address = MR11 address) from MR14 (S6 in FIG. 13) checks the gateway address and sequence number for these GWOs, When the gateway address and the sequence number are the same, both are determined to be GWOs transmitted from the MR 11 at the same timing.

  MR 13 receives GWO (gateway address = MR11 address) from both adjacent MR12 and MR14 (S7 in FIG. 13), and therefore does not transmit GWO (gateway address = MR11 address) any more (S8 in FIG. 13). .

  If the GWO (gateway address = MR11 address) is not received from either of the adjacent MR12 and MR14 for some reason (S7 in FIG. 13), the adjacent MR that has not been received (is not the source of the GWO) In response, GWO (gateway address = MR11 address) is transmitted (S9 in FIG. 13).

  In the example of FIG. 2, similarly, the MR 13 floods MR12 and MR14 adjacent to itself (which is one hop) with GWO (gateway address = MR13 address) indicated by a one-dot chain line arrow in FIG. S3).

  MR12 which received GWO (gateway address = MR13 address) from MR13, if no GWO (gateway address = MR13 address) is received from adjacent MR11, transmits GWO (gateway address = MR13 address) to MR11 as it is. To do.

  Further, if MR14 that has received GWO (gateway address = MR13 address) from MR13 does not receive GWO (gateway address = MR13 address) from the adjacent MR11, MR14 directly receives GWO (gateway address = MR13 address). (S4, S5 in FIG. 13).

  MR11 which received GWO (Gateway address = MR13 address) from MR12 and GWO (Gateway address = MR13 address) from MR14 (S6 in FIG. 13) checks the gateway address and sequence number for these GWOs, When the gateway address and the sequence number are the same, it is determined that both are GWOs transmitted from the MR 13 at the same timing.

  MR 11 receives GWO (gateway address = MR 13 address) from both of adjacent MR 12 and MR 14 (S 7 in FIG. 13), and therefore does not transmit GWO (gateway address = MR 13 address) any more (S 8 in FIG. 13). .

  If the GWO (gateway address = MR13 address) is not received from either of the adjacent MR12 and MR14 for some reason (S7 in FIG. 13), the GWO (gateway address) is set to the unreceived adjacent MR. = MR13 address) (S9 in FIG. 13).

  Here, MR1 recognizes that there is a gateway (gateway address = MR13 address) other than itself by receiving GWO (gateway address = MR13 address). Similarly, MR3 recognizes that there is a gateway (gateway address = MR11 address) other than itself by receiving GWO (gateway address = MR11 address) (S10 in FIG. 13).

  Next, the gateways (MR11, MR13) that have recognized that there is a gateway other than themselves are the priority of their own gateway, or the loss rate, delay, received signal strength, bandwidth of the radio link with the external network 2 Of one or more or all of the wireless link information and the priority of other MR gateways by the received GWO, or the loss rate, delay, received signal strength, bandwidth, etc. of the wireless link with the external network 2 By comparing one or a plurality or all of the wireless link information consisting of the above, ranking is performed in all gateways (S11 in FIG. 13).

  In FIG. 2, MR 11 compares its gateway priority or radio link information with MR 13's gateway priority or radio link information based on the received GWO (gateway address = MR13 address) and ranks itself ( 13 (S11 in FIG. 13), when the rank is within the set number of systems, that is, the set number of gateways (S12 in FIG. 13), when the rank continues exceeding the gateway (S13 in FIG. 13) and exceeds the set number of gateways The gateway is canceled (S14 in FIG. 13).

  Similarly, the MR 13 ranks itself in all gateways by comparing its own information with the gateway priority in the received GWO (gateway address = MR11 address) or radio link information with the external network ( 13 (S11 in FIG. 13), if the rank is within the set number of systems (S12 in FIG. 13), it continues the gateway (S13 in FIG. 13), and cancels the gateway if the rank exceeds the set number (FIG. 13). 13 S14).

  Here, it is assumed that MR11 has a higher rank, MR11 continues the gateway, and MR13 cancels the gateway. Here, each of the mobile networks 1A to 1D in the ad hoc network 1 can be connected to the external network 2 via the gateway MR11, but cannot be connected to the external network 2 via the MR13.

  Next, in FIG. 3, the MR 11 that continues the connection gateway with the external network 2 sets a gateway bit indicating that it is a gateway in the GWO periodically (I bit = ON) when the radio link information changes, and the MR 11 3 is flooded in the ad hoc network 1 and the gateway connected to the external network 2 is canceled, and the MR 13 periodically or when the radio link information changes changes the gateway in the GWO. 3 is flooded in the ad hoc network 1 (S15 in FIG. 13) without setting the gateway bit indicating that it is (I bit = OFF) and adding the MR13 address to the GWO indicated by the one-dot chain line arrow in FIG.

  If “2” is set as the number of gateways for the ad hoc network 1 to connect to the external network 2 by the system setting, both MR11 and MR13 are within the setting order, and both MR11 and MR13 are gateways. As shown in the example of FIG. 4, the gateway bits in the GWO are set (I bit = ON), and the gateway bits in the GWO and GWO indicated by the thin solid arrows with the MR11 address are set (I bit = ON ), And the GWO indicated by the one-dot chain line arrow with the MR13 address is flooded in the ad hoc network 1. In this case, each of the mobile networks 1A to 1D in the ad hoc network 1 can be connected to the external network 2 via the gateways MR11 and MR13.

(2) Change of Gateway Next, a case where the gateway connected to the external network 2 is changed by moving the ad hoc network 1 or MR constituting the ad hoc will be described with reference to FIGS.

  In the description of the gateway selection, the MR 13 that has canceled the gateway in FIG. 3 has its own ranking within the set number of gateways due to the change of its own radio link information or the received radio link information of the G11 (gateway address = MR11 address) of the MR 11. (S15 → S6 to S12 in FIG. 13), as shown in FIG. 5, MR13 becomes a new gateway (gateway restart: S13 in FIG. 13), indicating that it is a gateway in the GWO. A gateway bit is set (I bit = ON), and GWO (gateway address = MR13 address) indicated by a one-dot chain arrow is flooded in the ad hoc network 1 (S15 in FIG. 13).

  In MR11, when its own ranking exceeds the set number of gateways due to a change in its own radio link information or the received radio link information of MR13 GWO (gateway address = MR13 address) (S15 → S6 in FIG. 13). S12) Cancels the gateway (S14 in FIG. 13), and does not set the gateway bit (I bit = OFF), and floods the GWO (gateway address = MR11 address) indicated by the thin solid arrow into the ad hoc network 1 (FIG. 13). 13 S15).

  At this time, each of the mobile networks 1A to 1D in the ad hoc network 1 can be connected to the external network 2 via the gateway MR13, but cannot be connected to the external network 2 via the MR11, and the gateway is changed. It will be broken. Since the operations of MR13 and MR11 are performed asynchronously, depending on the timing, MR11 and MR13 may become gateways at the same time, or the gateway may temporarily disappear, but the gateway can be changed in a short time. Is possible.

  Further, as shown in FIG. 6, the MR 11 has the priority of its own gateway or the radio link information with the external network 2 and the priority or the radio link information of the gateway of the MR 13 based on the received GWO (gateway address = MR13 address). And MR11 continues to be a gateway within the set number of gateways. Similarly, MR13 has its own information and the gateway in the received GWO (gateway address = MR11 address). By comparing the priority or the radio link information of each of the gateways, the gateways themselves are ranked and the number of gateways exceeds the set number of gateways. Sometimes shown by thin solid arrows in FIG. The MR 13 that floods the GWO and stops the connection gateway with the external network 2 is within the scope of the present invention even when the GWO is not transmitted (corresponding to the dotted arrow after S14 in FIG. 13).

  In this case, in the MR 13 that has canceled the gateway, its own ranking is set by a change in its own radio link information or in the received radio link information of the GWO (gateway address = MR11 address) indicated by a thin solid arrow in FIG. When the rank is within the number of gateways, the MR 13 becomes a new gateway as shown in the example of FIG. 7, and the GWO (gateway address = MR13 address) indicated by the one-dot chain line arrow is flooded in the ad hoc network 1.

  Next, MR 11 receives GWO (gateway address = MR13 address) indicated by a one-dot chain line arrow in FIG. 8 from MR 13 which becomes a new gateway, and receives its own radio link information or GWO of the received MR 13 (gateway address = When the ranking of the self-ranking exceeds the set number of gateways due to the change of the radio link information of (MR13 address), the gateway is canceled and the transmission of GWO (gateway address = MR11 address) is canceled as in the example of FIG. In this case, since MR 11 cancels the gateway after MR 13 becomes a gateway, it takes time to change the gateway, but the gateway is not temporarily lost.

  The gateway selection and change method has been described above. Next, a description will be given of a method for preventing the MR selected as the gateway from frequently changing the gateway due to slight fluctuations in the radio link information.

  After the MR 11 is connected to the external network 2 through a wireless link and becomes a gateway, the MR 11 receives the GWO (gateway notification packet), receives the information of itself and the priority or the wireless link information of the gateway in the received G 13 of the MR 13. As a result of comparing each gateway in the comparison, the ranking is within the number of set gateways. If the gateway continues to be a gateway, the loss rate, delay, and received signal strength of the radio link with the external network 2 Multiply your wireless link information such as bandwidth by the preferential degree, and by installing the wireless link information multiplied by the preferential degree in the GWO and flooding it, the loss rate, delay, and reception of the wireless link at the gateway once elected Gaming due to slight fluctuations in radio link information such as signal strength and bandwidth Way switched so as not to generate.

  For example, when the system is set to preferential degree = 1.1 (10% preferential degree), MR11 becomes the gateway when (MR11 wireless link information = 0.8)> (MR13 wireless link information = 0.7). If selected, MR11 radio link information × preferential degree = 0.8 × 1.1 = 0.88. At this time, even if MR11 radio link information = 0.7 and MR13 radio link information = 0.75, (MR11 radio link information × preferential degree = 0.7 × 1.1 = 0.77) > (MR13 radio link information = 0.75), MR11 is favored, and gateway change does not occur.

  Even in this case, if MR11 radio link information = 0.7 and MR13 radio link information = 0.8, (MR11 radio link information × preferential degree = 0.7 × 1.1 = 0.77) <(MR13 radio link information = 0.8), and gateway change occurs.

  Next, when the ad hoc network 1 or MR 11 constituting the ad hoc moves and the access router AR1 that is the connection destination for the MR 11 to connect to the external network 2 is switched to the AR 2, switching from the AR 1 to the AR 2 is short. If it is time, a method of performing a smooth handover without changing the gateway will be described.

  After the MR 11 is connected to the external network 2 via a radio link and becomes a gateway, the MR 11 receives the GWO from the MR 13 and receives the information of itself and the gateway priority in the GWO of the MR 13 or the radio link with the external network 2. By comparing one or more or all of wireless link information such as loss rate, delay, received signal strength, bandwidth, etc., as a result of ranking itself in all gateways, the ranking is within the set number of gateways. When the connection destination for connecting the MR 11 to the external network 2 is switched from the AR 41 to the AR 42 due to the movement of the MR 11 or a change in the wireless environment after continuing the gateway, the connection with the external network 2 in the MR 11 is temporarily changed. The radio link is blocked, loss rate, delay, received signal Every time, there is the radio link information, such as bandwidth is degraded.

  Even in that case, the radio link information such as the loss rate, delay, received signal strength, and bandwidth of the radio link with the external network 2 reflects the latest value during handover so that the gateway switching flutter does not occur. Rather than hold the value before the handover, and the loss rate is maintained during the loss rate measurement period even after the handover, due to the temporary degradation of the radio link information It becomes possible to prevent the gateway from being changed.

  Similarly, when a radio parameter change such as a change in radio transmission rate is performed, the radio link may be temporarily cut off, or radio link information such as loss rate, delay, received signal strength, and bandwidth may deteriorate. Even in this case, during the wireless parameter change, the wireless link information such as the loss rate, delay, received signal strength, and bandwidth of the wireless link with the external network 2 does not reflect the latest value but before the wireless parameter change. In addition, the loss rate is maintained during the loss rate measurement period even after the radio parameter is changed, thereby preventing the gateway from being changed due to temporary deterioration of the radio link information. It becomes possible.

  In the above example, assuming that the number of radio links between the ad hoc network 1 and the AR of the external network 2 constituting the ad hoc or the number of ARs is limited, the number of gateways connected in the system setting is limited. Explained the operation of selecting the gateway when it was provided (representative gateway method).

  Next, an operation when there is no restriction on the number of radio links between the ad hoc network 1 and the access router AR of the external network 2 constituting the ad hoc or the number of ARs will be described. When there is no restriction on the number of gateways for the ad hoc network 1 to connect to the external network 2, it can be connected to the external network 2 through a wireless link, or can be connected at a predetermined quality or higher with the above-mentioned wireless link information of the wireless link All MRs autonomously become gateways regardless of the number of gateways in the ad hoc network 1 and can continue to be connected to the external network 2 via radio links regardless of the priority and radio link information of other gateways, or If the wireless link information can be connected with a predetermined quality or higher, the gateway is continued (individual gateway method).

  Next, in FIG. 9, when MR11 and AR41 and MR13 and AR43 are connected by a radio link, or one or more or all of radio link information such as loss rate, delay, received signal strength, and bandwidth of the radio link MR11 and MR13 serve as gateways in the ad hoc network 1 when the connection can be established with a predetermined quality or higher. At this point, each of the mobile networks 1A to 1D in the ad hoc network 1 can be connected to the second network via the gateways MR11 and MR13. Thereafter, MR11 and MR13 may or may not flood the GWO, and both MR11 and MR13 have their own radio link information regardless of the priority of the gateway and the radio link information. All MRs that can connect to the external network 2 continue the gateway.

  The ad hoc network may be one that performs one-hop communication or multi-pop communication.

  As described above, in the above embodiment, when an ad hoc network is configured by a plurality of mobile routers, the mobile router serving as a gateway to an external network transmits a gateway notification packet, whereby each mobile router It is decided to select and change the gateway by determining that the gateway will continue, cancel, or become a new gateway. Thereby, the selection and change of the gateway can be realized by the autonomous distributed control of each mobile router without requiring a special node.

  In the above embodiment, the case where the mobile router constitutes an ad hoc network that is a mobile network has been described. However, instead of the mobile router, a wireless router, a mobile IP terminal, or a radio base station constitutes a network. Also, the processing of the above embodiment can be applied, and the same effect can be obtained.

  In the above embodiment, each mobile router manages a mobile network prefix and a home address. However, only one of them may be managed.

  When a mobile IP terminal is adopted instead of the mobile router, the mobile IP terminal manages the home address but does not manage the mobile network prefix.

  When a wireless router is adopted instead of a mobile router, a home agent is not installed in the external network, and movement management between the mobile router and the home agent is not performed, but the processing of the above embodiment is possible, and the same The effect of.

  In addition, when processing for linking bandwidth control and congestion avoidance control for speeding up TPC (Transmission Control Protocol) with a pair of opposing connections between the gateway and the home agent 51 is performed, It is possible to ensure continuity of processing by exchanging information for control between the new gateways.

It is a figure which shows an example of a structure of the communication system containing the ad hoc network by one embodiment of this invention. It is a schematic diagram for demonstrating operation | movement of the communication system of FIG. It is a schematic diagram for demonstrating operation | movement of the communication system of FIG. It is a schematic diagram for demonstrating operation | movement of the communication system of FIG. It is a schematic diagram for demonstrating operation | movement of the communication system of FIG. It is a schematic diagram for demonstrating operation | movement of the communication system of FIG. It is a schematic diagram for demonstrating operation | movement of the communication system of FIG. It is a schematic diagram for demonstrating operation | movement of the communication system of FIG. It is a schematic diagram for demonstrating operation | movement of the communication system of FIG. It is a figure which shows an example of a structure of the mobile communication apparatus (mobile router) by this invention. It is a figure which shows an example of a format of the gateway notification packet (GWO) in this invention. It is a timetable explaining an example of the operation | movement sequence at the time of gateway selection and gateway change between the mobile router of the ad hoc network in this invention, and the access router of an external network. It is a flowchart which shows the operation | movement at the time of gateway selection and change in each mobile router in this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Ad hoc network, 1A-1D mobile network, 2 External network, 6 Opposite node, 11-14 Mobile router (MR) (gateway), 21-24 Mobile network prefix (MNP), 31-34 Terminal in mobile network (MN) 41 to 43 access router (AR), 51 home agent (HA), 70-1 to 70-n interface, 71 packet control unit, 72 packet transfer processing unit, 73 route control unit, 74 gateway control unit, 76 packet transfer Part, 77 routing control table.

Claims (24)

A first network that is a mobile network in which a plurality of mobile communication devices form an ad hoc network; and a second network that is a fixed network connected to the first network so as to be able to perform wireless communication. A communication system including an ad hoc network in which the mobile communication device having a predetermined number of gateways or less for communicating with the second network serves as a gateway and communicates with the second network,
Each of the plurality of mobile communication devices is
When the wireless link can be connected to the second network or at least one of the wireless link information including the loss rate, delay, received signal strength, and bandwidth of the wireless link with the second network can be connected with a predetermined quality or higher A predetermined gateway notification packet including at least one of the gateway priority and the wireless link information with the second network, together with its own IP address, in order to become a gateway and notify that it is a gateway. Broadcast or multicast to each mobile communication device in the first network;
The gateway notification packet sent from the mobile communication device in the first network is broadcast or multicast to other mobile communication devices in the first network, and the duplicate gateway notification packet is discarded and transferred. Flooding the gateway notification packet into the first network by sending the gateway notification packet to all possible mobile communication devices;
If the mobile communication device is in a state of being a gateway, at least one of the gateway priority of the gateway notification packet or the radio link information from another mobile communication device that is a gateway in the first network It ranks itself within the first network according to the comparison result, and if it ranks within the number of gateways, it continues the gateway, and if the rank exceeds the set number of gateways, cancels the gateway. Gateway control means,
A communication system including an ad hoc network. The gateway control means
When the number of gateways is within the order and the gateway is continued, the gateway bit is set in the gateway notification packet periodically or when the radio link information changes, and the gateway notification packet is flooded in the first network. And
The gateway notification packet is flooded into the first network without setting the gateway bit periodically or when the radio link information changes when the gateway is in a rank exceeding the number of gateways. A communication system including the ad hoc network according to claim 1. The gateway control means
After canceling the gateway, if the rank is within the number of gateways due to a change in the radio link information of the own or the received gateway notification packet, the gateway becomes a new gateway, and the gateway bit is set by setting the gateway bit. Flood the notification packet into the first network;
While the gateway is continuing, a gateway notification packet with a gateway bit set from the mobile communication device that has become a new gateway is received, and the gateway is determined by the change in the wireless link information of the own wireless link information or the received gateway notification packet The gateway is changed by canceling the gateway when the rank exceeds the number, and flooding the gateway notification packet into the first network without setting the gateway bit. A communication system including the described ad hoc network. The gateway control means
When the gateway is in a rank within the number of gateways and continues the gateway, the gateway notification packet is flooded into the first network periodically or when the radio link information changes,
The communication system including an ad hoc network according to claim 1, wherein the gateway notification packet is not flooded when the number of gateways is higher than the number of gateways and the gateway is canceled. The gateway control means
After canceling the gateway, if the rank is within the number of gateways due to a change in the radio link information of the radio link information or the received gateway notification packet, the gateway becomes a new gateway, and the gateway notification packet is changed to the first Flooded into the network,
While the gateway continues, a gateway notification packet is received from the mobile communication device that has newly become a gateway, and due to a change in the wireless link information of the own wireless link information or the received gateway notification packet, the rank exceeding the number of gateways 5. The communication system including an ad hoc network according to claim 1, wherein the gateway is canceled and the gateway notification packet is not flooded. Gateway control means
In the state of becoming a gateway, it receives a gateway notification packet and compares its own and at least one of the gateway priority or the radio link information in all the received gateway notification packets to As a result of ranking, when the ranking is within the set number of gateways and continues to be a gateway, the wireless link information is multiplied by the preferential degree and includes the wireless link information multiplied by the preferential degree. The communication system including an ad hoc network according to claim 1, wherein the gateway notification packet is flooded. The gateway control means
In the state of becoming a gateway, it receives a gateway notification packet and compares its own and at least one of the gateway priority or the radio link information in all the received gateway notification packets to As a result of performing the ranking, if the ranking is within the set number of gateways and continues itself, the radio link information retains the previous value during handover and radio parameter change, and 2. The communication system including an ad hoc network according to claim 1, wherein the loss rate retains the previous value during the loss rate measurement period even after handover and radio parameter change. A first network that is a mobile network in which a plurality of mobile communication devices form an ad hoc network; and a second network that is a fixed network connected to the first network so as to be able to perform wireless communication. A communication system including an ad hoc network that communicates with the second network, with each mobile communication device of the network serving as a gateway for communicating with the second network,
Each of the plurality of mobile communication devices is
When the wireless link can be connected to the second network or at least one of the wireless link information including the loss rate, delay, received signal strength, and bandwidth of the wireless link with the second network can be connected with a predetermined quality or higher Gateway control means for operating the mobile communication device as a gateway as long as it is in a state;
A communication system including an ad hoc network. A first network that is a mobile network in which a plurality of mobile communication devices form an ad hoc network; and a second network that is a fixed network connected to the first network so as to be able to perform wireless communication. Mobile communication for a communication system including an ad hoc network that communicates with the second network, with the mobile communication device having a predetermined number of gateways or less for communicating with the second network serving as a gateway serving as a gateway A device,
When the wireless link can be connected to the second network or at least one of the wireless link information including the loss rate, delay, received signal strength, and bandwidth of the wireless link with the second network can be connected with a predetermined quality or higher A predetermined gateway notification packet including at least one of the gateway priority and the wireless link information with the second network, together with its own IP address, in order to become a gateway and notify that it is a gateway. Broadcast or multicast to each mobile communication device in the first network;
The gateway notification packet sent from the mobile communication device in the first network is broadcast or multicast to other mobile communication devices in the first network, and the duplicate gateway notification packet is discarded and transferred. Sending the gateway notification packet to all possible mobile communication devices;
If the mobile communication device is in a state of being a gateway, at least one of the gateway priority of the gateway notification packet or the radio link information from another mobile communication device that is a gateway in the first network It ranks itself within the first network according to the comparison result, and if it ranks within the number of gateways, it continues the gateway, and if the rank exceeds the set number of gateways, cancels the gateway. Gateway control means,
A mobile communication device for a communication system including an ad hoc network. The gateway control means
When the number of gateways is within the order and the gateway is continued, the gateway bit is set in the gateway notification packet periodically or when the radio link information changes, and the gateway notification packet is flooded in the first network. And
The gateway notification packet is flooded into the first network without setting the gateway bit periodically or when the radio link information changes when the gateway is in a rank exceeding the number of gateways. A mobile communication device for a communication system including the ad hoc network according to claim 9. The gateway control means
After canceling the gateway, if it becomes a rank within the number of gateways due to a change in the wireless link information of itself or the received gateway notification packet, it becomes a new gateway, and the gateway bit is set by setting the gateway bit. Flood the notification packet into the first network;
While the gateway is continuing, a gateway notification packet with a gateway bit set from the mobile communication device that has become a new gateway is received, and the gateway is determined by the change in the wireless link information of the own wireless link information or the received gateway notification packet. The gateway is changed by canceling the gateway and flooding the gateway notification packet into the first network without setting the gateway bit when the ranking exceeds the number. A mobile communication device for a communication system comprising the described ad hoc network. The gateway control means
When the rank is within the number of gateways and the gateway is continued, the gateway notification packet is flooded into the first network periodically or when the radio link information changes,
The mobile communication device for a communication system including an ad hoc network according to claim 9, wherein the gateway notification packet is not flooded when the gateway is canceled and the gateway is canceled. The gateway control means
After canceling the gateway, if the rank is within the number of gateways due to a change in the radio link information of the radio link information or the received gateway notification packet, the gateway becomes a new gateway, and the gateway notification packet is changed to the first Flooded into the network,
While the gateway continues, a gateway notification packet from a mobile communication device that has newly become a gateway is received, and due to a change in the wireless link information of the own wireless link information or the received gateway notification packet, the rank exceeding the number of gateways 13. The mobile communication device for a communication system including an ad hoc network according to claim 9 or 12, wherein the gateway is canceled and the gateway notification packet is not flooded. The gateway control means
In the state of becoming a gateway, it receives a gateway notification packet and compares its own and at least one of the gateway priority or the radio link information in all the received gateway notification packets to As a result of ranking, when the ranking is within the set number of gateways and continues to be a gateway, the wireless link information is multiplied by the preferential degree and includes the wireless link information multiplied by the preferential degree. The mobile communication apparatus for a communication system including an ad hoc network according to claim 9, wherein the gateway notification packet is flooded. The gateway control means
In the state of becoming a gateway, it receives a gateway notification packet and compares its own and at least one of the gateway priority or the radio link information in all the received gateway notification packets to As a result of performing the ranking, if the ranking is within the set number of gateways and continues itself, the radio link information retains the previous value during handover and radio parameter change, and 10. The mobile communication apparatus for a communication system including an ad hoc network according to claim 9, wherein the loss rate retains the previous value during the period of loss rate measurement even after handover and radio parameter change. . A first network that is a mobile network in which a plurality of mobile communication devices form an ad hoc network; and a second network that is a fixed network connected to the first network so as to be able to perform wireless communication. A mobile communication device for a communication system including an ad hoc network that serves as a gateway for communication with the second network by each mobile communication device of the second network,
When the wireless link can be connected to the second network or at least one of the wireless link information including the loss rate, delay, received signal strength, and bandwidth of the wireless link with the second network can be connected with a predetermined quality or higher Gateway control means for operating the mobile communication device as a gateway as long as it is in a state;
A mobile communication device for a communication system including an ad hoc network. A first network that is a mobile network in which a plurality of mobile communication devices form an ad hoc network; and a second network that is a fixed network connected to the first network so as to be able to perform wireless communication. A communication method in a communication system including an ad hoc network in which the mobile communication device having a predetermined number of gateways or less for communicating with the second network serves as a gateway and communicates with the second network. There,
In each of the mobile communication devices, at least one of radio link information including a loss rate, a delay, a received signal strength, and a band of a radio link with the second network when it can be connected to the second network via a radio link is provided. When it is possible to connect with a predetermined quality or higher, it becomes a gateway and notifies itself that it is a gateway. Therefore, together with its IP address, at least one of the gateway priority and the radio link information with the second network Broadcast or multicast a predetermined gateway notification packet including a message to each mobile communication device in the first network
The gateway notification packet sent from the mobile communication device in the first network is broadcast or multicast to other mobile communication devices in the first network, and the duplicate gateway notification packet is discarded and transferred. Sending the gateway notification packet to all possible mobile communication devices;
If the mobile communication device is in a state of being a gateway, at least one of the gateway priority of the gateway notification packet from the other mobile communication device that is a gateway in the first network or the radio link information It ranks itself within the first network according to the comparison result, and if it ranks within the number of gateways, it continues the gateway, and if the rank exceeds the set number of gateways, cancels the gateway. Gateway control process,
A communication method in a communication system including an ad hoc network. In the gateway control process,
When the number of gateways is within the order and the gateway is continued, the gateway bit is set in the gateway notification packet periodically or when the radio link information changes, and the gateway notification packet is flooded in the first network. And
The gateway notification packet is flooded into the first network without setting the gateway bit periodically or when the radio link information changes when the gateway is in a rank exceeding the number of gateways. A communication method in a communication system including the ad hoc network according to claim 17. In the gateway control process,
After canceling the gateway, if the rank is within the number of gateways due to a change in the radio link information of the own or the received gateway notification packet, the gateway becomes a new gateway, and the gateway bit is set by setting the gateway bit. Flood the notification packet into the first network;
While the gateway is continuing, a gateway notification packet with a gateway bit set from the mobile communication device that has become a new gateway is received, and the gateway is determined by the change in the wireless link information of the own wireless link information or the received gateway notification packet. 19. The gateway according to claim 17 or 18, wherein when the ranking exceeds a number, the gateway is canceled and the gateway notification packet is flooded in the first network without setting the gateway bit to change the gateway. A communication method in a communication system including the described ad hoc network. In the gateway control process,
When the gateway is in a rank within the number of gateways and continues the gateway, the gateway notification packet is flooded into the first network periodically or when the radio link information changes,
18. The communication method in a communication system including an ad hoc network according to claim 17, wherein the gateway notification packet is not flooded when the gateway is canceled and the gateway is canceled. In the gateway control process,
After canceling the gateway, if the rank is within the number of gateways due to a change in the radio link information of the radio link information or the received gateway notification packet, the gateway becomes a new gateway, and the gateway notification packet is changed to the first Flooded into the network,
While the gateway continues, a gateway notification packet from a mobile communication device that has newly become a gateway is received, and due to a change in the wireless link information of the own wireless link information or the received gateway notification packet, the rank exceeding the number of gateways 21. The communication method in a communication system including an ad hoc network according to claim 17 or 20, wherein the gateway is canceled and the gateway notification packet is not flooded. In the gateway control process,
In the state of becoming a gateway, it receives a gateway notification packet and compares its own and at least one of the gateway priority or the radio link information in all the received gateway notification packets to As a result of ranking, when the ranking is within the set number of gateways and continues to be a gateway, the wireless link information is multiplied by the preferential degree and includes the wireless link information multiplied by the preferential degree. The communication method in a communication system including an ad hoc network according to claim 17, wherein the gateway notification packet is flooded. In the gateway control process,
In the state of becoming a gateway, it receives a gateway notification packet and compares its own and at least one of the gateway priority or the radio link information in all the received gateway notification packets to As a result of performing the ranking, if the ranking is within the set number of gateways and continues itself, the radio link information retains the previous value during handover and radio parameter change, and 18. The communication method in a communication system including an ad hoc network according to claim 17, wherein the loss rate retains the previous value during the loss rate measurement period even after handover and radio parameter change. A first network that is a mobile network in which a plurality of mobile communication devices form an ad hoc network; and a second network that is a fixed network connected to the first network so as to be able to perform wireless communication. A communication method in a communication system including an ad hoc network in which each mobile communication device of the first network serves as a gateway for communicating with the second network and communicates with the second network,
In each of the mobile communication devices,
When the wireless link can be connected to the second network or at least one of the wireless link information including the loss rate, delay, received signal strength, and bandwidth of the wireless link with the second network can be connected with a predetermined quality or higher A gateway control step for operating the mobile communication device as a gateway as long as it is in a state;
A communication method in a communication system including an ad hoc network.

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