JP2009112036A - Broadcasting system, its broadcasting method, and broadcasting program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide broadcasting communication suitable for a radio multi-hop network to perform radio relay broadcasting. <P>SOLUTION: The broadcasting system includes: a means for distributing a transmitted message with a true destination address, a true source address, an adjacent destination address and an adjacent source address, performing distribution along a route by uni-casting and performing broadcasting effective only in one hop; a means for performing broadcasting with an address of a previous hop included in a message field and canceling a message with the next node set for the previous hop address; a means for once distributing a broadcast message to a route node or the tip of the route to perform broadcasting and relaying only a broadcast received from an upstream node; and a means for performing distribution along the route by uni-casting and confirming the true destination address at a terminal. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a broadcast in a communication network, and more particularly to a broadcast system, a broadcast method thereof, and a broadcast program for executing a broadcast in a wireless network.

  Broadcast in the network is a communication method that is received by all nodes in the network by sending a message once.

  For example, in a network connected by wire, a broadcast message is delivered along a previously generated route and delivered to all relay nodes and terminal nodes. If the route of the network is appropriately configured, the relay node that has received the broadcast message can deliver the message to all the nodes by sequentially transmitting to the route other than the received route.

  On the other hand, in a wireless network, a broadcast message is delivered to all nodes that are within reach of the wireless signal of the transmitting node. Wireless networks, such as cellular systems, have a one-hop link that uses radio and a wireless multi-hop system that relays wirelessly. In the former case, the radio link is always one hop, and in the case of broadcasting by radio, the radio base station broadcasts to terminals in the area of its own node, and each terminal receives and ends.

  For example, FIG. 15 shows that the terminal 30a belongs to the radio base station 20-1a, and the radio base stations 20-1a and 20-2a, 20-2a and the bridges 10a and 20-3a are routed between the radio base stations. Assume that the bridge 10a is a network in which the bridges 10a and 20-4a are connected by wire.

  Here, when the terminal 30a broadcasts a message, it is first transmitted to the radio base station 20-1a to which it belongs by unicast. Here, in order to deliver the broadcast message to other terminals in the area of the own node, the radio base station 20-1a performs broadcast by radio and further, a radio base station 20- that is a route connected by wire. To 2a. Upon receiving this message, the radio base station 20-2a broadcasts wirelessly to terminals in the area of its own node, and transmits to the bridge 10a, which is a route destination other than the transmission source of the received broadcast message, according to a wired route. . The bridge 10a that has received this message transmits to the radio base stations 20-3a and 20-4a, which are route destinations other than the transmission source of the received broadcast message, according to the route, and hereinafter the radio base stations 20-3a and 20-4a Broadcasts wirelessly toward the terminal in its own node.

  As described above, in a wireless network such as a cellular system, broadcasting by radio always ends with one hop, and even if a certain radio base station receives a message broadcast by another radio base station, it further broadcasts. There is no such thing.

  In a multi-hop system that relays wirelessly, when the same wireless resource is used for a route between wireless base stations, a problem arises because it is not possible to control that the route that received the broadcast message is not transmitted.

  For example, it is assumed that the wireless base stations 20-1a and 20-2a, 20-2a and the bridge 10a, and the bridge 10a and the wireless base stations 20-3a and 20-4a in FIG.

  When the terminal 30a broadcasts, it is as follows. When a route is set wirelessly, it is necessary to discard the message when a message is received from a route other than the route at the relay node. However, a relay process is required for a message received from the correct route. For example, when a broadcast message is received from the correct route, the message is further broadcast. In the example of FIG. 15, the radio base station 20-1a that has received the broadcast message (step A) from the terminal 30a performs radio broadcast (step B), and the radio base station 20-2a that has received the broadcast is radio. When broadcasting is performed (steps C and D), the radio base station 20-1a receives a broadcast message from the radio base station 20-2a which is the correct route. Since the broadcast message received from the correct path needs to be further broadcasted, a broadcast storm occurs in which the same broadcast message transmitted by the own node (radio base station 20-1a) is further broadcast.

  As described above, the conventional techniques have the following problems.

  First, in a conventional multi-hop system that relays using radio, a broadcast storm occurs when a message is broadcast by radio. This is because even when an appropriate route using a wireless link is configured in the network, the broadcast message transmitted from the own node is broadcast again by the node that has received the broadcast message. This is because the broadcast message is received as a broadcast message from the correct route.

  Secondly, when a broadcast message is received, the method of transmitting each unicast to a node for which a route is set in advance is like mobile communication where there is a possibility that a terminal whose position is not known exists. It does not function correctly in a large network. This is because the broadcast message is delivered by unicast, and is not delivered to a node whose position is not known.

  The object of the present invention is to solve the above-mentioned drawbacks of the prior art, and in a wireless multi-hop network using wireless relay, effective broadcast is possible even for a terminal whose position is not recognized without generating a broadcast storm. It is to provide a way to do it.

In order to achieve the above object, a broadcast system according to the present invention is a broadcast system that broadcasts messages on a wireless network. , A true destination address indicating the final destination of the message, a true source address indicating the first source of the message, and an adjacent transmission indicating the destination of the message in the transfer between adjacent nodes Means for transmitting the destination address and the data of the adjacent transmission source address indicating the transmission source of the message in the transfer between adjacent nodes by adding to the message;
A mobile terminal including a means for transmitting a broadcast message to an adjacent node using unicast communication along a preset route, and the mobile terminal receiving the broadcast message has a broadcast address set as a true destination address When a message is received, if there is a radio base station to which the mobile terminal currently belongs in the communication area, the message is received only if the adjacent destination address is set to the own node. When there is no radio base station to which the mobile terminal belongs, the message reception process is always performed.

  The mobile terminal of the present invention, in a mobile terminal that receives a broadcast message transmitted via a wireless network, a true transmission destination address indicating the final transmission destination of the message and an initial transmission source of the message Data of the true source address indicating the destination, the adjacent destination address indicating the destination of the message in the transfer between adjacent nodes, and the adjacent source address indicating the source of the message in the transfer between adjacent nodes. There is a radio base station to which the mobile terminal currently belongs in the communication area at the time of receiving a message in which a broadcast address is set as a true transmission destination address and a means for receiving a message to be added and transmitted In this case, the message concerned only when the adjacent destination address is set in the local node. It performs reception processing, when the radio base station to which the mobile terminal belongs is not present, always includes a means for performing a reception process of the message.

  The broadcast method of the present invention is a broadcast method in which a message is broadcast on a wireless network. Each node that transmits / receives / relays a message with respect to a message communicated with another node finally transmits the message. Adjacent to the true destination address indicating the correct destination, the true source address indicating the first source of the message, and the adjacent destination address indicating the destination of the message in the transfer between adjacent nodes A step of adding data of an adjacent source address indicating the source of the message in the transfer between nodes to the message and transmitting the message, and a broadcast message adjacent to each other using unicast communication along a preset route Broadcast to a node that When a mobile terminal that receives a mobile message has a wireless base station to which the mobile terminal currently belongs in the communication area when receiving a message in which a broadcast address is set as a true destination address, The process of receiving the message is performed only when the adjacent destination address is set to the own node. When there is no radio base station to which the mobile terminal belongs, the step of always performing the message reception process is performed. Including.

  The broadcast program of the present invention is a broadcast program that broadcasts a message on a wireless network. For a message that is communicated with other nodes to each node that transmits / receives / relays a message, the final program of the message is transmitted. Adjacent to the true destination address indicating the correct destination, the true source address indicating the first source of the message, and the adjacent destination address indicating the destination of the message in the transfer between adjacent nodes A process of adding the data of the adjacent transmission source address indicating the transmission source of the message in the transfer between the nodes to the message and transmitting the message, and the broadcast message adjacent to each other using unicast communication along a preset route Execute the process to send to the node that When a mobile terminal that receives a docast message receives a message in which a broadcast address is set as a true destination address, and there is a radio base station to which the mobile terminal currently belongs in the communication area The process of receiving the message only when the adjacent destination address is set to the own node, and always performing the process of receiving the message when there is no radio base station to which the mobile terminal belongs Is executed.

As described above, according to the present invention, the following effects are achieved.
First, in a wireless multi-hop network that relays using radio, it is possible to broadcast correctly and eliminate the occurrence of broadcast storms.

  Second, it is possible to deliver a broadcast message to a terminal in which information regarding a route is not registered.

  Thirdly, broadcast can be performed by a system in which a broadcast message is delivered by unicast along a set route and broadcast by only one hop at each node.

  Fourth, the broadcast message includes the address of the node that transmitted the broadcast message that triggered the transmission of the broadcast message, and the node that received the broadcast message broadcasts from a node other than the adjacent node on the preset route. The message can be discarded.

  Fifth, the broadcast message is once delivered to the root node using unicast communication, and the root node that receives the broadcast message broadcasts, and in each node, from the upstream adjacent node in the preset route. Only a broadcast message can be used as a valid broadcast message for further broadcasting.

  Sixth, the relay node delivers a broadcast message using unicast communication along a pre-configured route, and the terminal confirms the true transmission destination included in the message. Can be performed.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 and 2 are diagrams showing an example of a configuration of a wireless multi-hop network to which the present invention is applied.

  Referring to FIG. 1 and FIG. 2, the network according to the present embodiment includes a terminal 30 (30-1, 30-2, 30-3) and a radio base station 20 (20-1, 20-2, 20-3, 20). -4, 20-5), and a wireless bridge 10, each of which is connected by a wireless link. Each terminal 30 is a terminal device (mobile terminal) that performs mobile communication, and the wireless base station 20 relays wireless communication by each terminal 30. The wireless bridge 10 is a higher-order base station that connects the wireless base stations 20 to each other.

  Moreover, the line which connects each node in a figure has shown the preset communication path | route. The terminal 30-3 that is not connected to any other node does not belong to any wireless base station communication area, and is in a state in which no route is configured. For example, when the terminal 30-1 communicates with the terminal 30-2, the wireless base stations 20-1, 20-2, 20-5, the wireless bridge 10, and the wireless base station 20-4 are connected using a wireless link. It goes through sequentially. Each of these relayed nodes becomes a relay node that relays the message.

  In constructing the route, for example, a spanning tree algorithm is used. In the spanning tree algorithm, a route control packet is used to construct a route that minimizes the route identification number and the cost to reach that route. By exchanging the route control packet, it is possible to recognize whether each adjacent node is an upstream node corresponding to the upstream on the route, a downstream node corresponding to the downstream on the route, or a node other than the route. Here, the upstream of the route indicates a side closer to the root node than a certain node, and the downstream indicates a side far from the root node.

  In a wireless multi-hop network, a logical route is created, but it is possible to receive messages from nodes other than the correct route. When only the destination is used, it is difficult for each node that receives the message to determine whether the message should be relayed or discarded.

  Therefore, in a wireless multi-hop network, a message used for communication includes a field indicating a final message transmission destination (hereinafter referred to as a true transmission destination) address, a transmission destination of an adjacent node (hereinafter referred to as an adjacent transmission). A field indicating the destination address, a field indicating the first transmission source address of the message (hereinafter referred to as the true transmission source), and a field indicating the transmission source address of the adjacent node (hereinafter referred to as the adjacent transmission source) are required. It is. In other words, when a message is sent and received between adjacent nodes on the generated route, the node that sent the message is called the adjacent transmission source, and the node that received the message is called the adjacent transmission destination. .

  FIG. 3 shows an example of the structure of a message having such fields. The data of each field is added to the data of the message body as shown in FIG. 3 and transmitted / received between the nodes.

  In FIG. 1, when the terminal 30-1 communicates with the terminal 30-2, in the message transmitted from the terminal 30-1 to the radio base station 20-1, the true transmission destination is the terminal 30-2, The transmission source is the terminal 30-1, the adjacent transmission destination is the radio base station 20-1, and the adjacent transmission source is the terminal 30-1.

  Further, when the radio base station 20-1 relays the message and transmits it to the radio base station 20-2, the true transmission destination and the true transmission source do not change between the terminal 30-2 and the terminal 30-1, and are adjacent to each other. The transmission source is the radio base station 20-1, and the adjacent transmission destination is the radio base station 20-2.

  Therefore, the true transmission destination and the true transmission source are set by the node that first generated the message, and are not changed at the relay node in the middle of the route, but are set according to the situation at the relay node. . When the address and route of communication are clear, unicast communication is performed, and the message is delivered along the route recorded in each node. In the above example, when the terminal 30-1 is a true destination for the radio base station 20-1, the next hop is the terminal 30-1, and when the terminal 30-2 is a true destination, the next hop is It is recorded that it is the radio base station 20-2, and the relay node such as the radio base station 20-1 relays the message based on the information.

  In the above description, address setting assuming unicast communication is described. However, in the case of broadcast, a broadcast address is used as an address.

  The communication layer for performing the control of the present invention is not particularly limited, but is located inside the data link layer in the OSI seven-layer model or in the middle of the IP layer and the MAC layer in the Internet, and can operate in cooperation with the MAC layer. It is. When operating in cooperation with the MAC, in the message configuration of FIG. 3, the adjacent transmission destination and the adjacent transmission source are MAC addresses handled in the MAC layer, and the true transmission source and the real transmission destination are handled in an upper layer of the MAC layer. It can be used as a MAC address.

  Next, a first embodiment of the present invention will be described with reference to the drawings.

  4, 5, and 6 are flowcharts for explaining the broadcast method according to the first embodiment. FIG. 4 is a process of a node that first transmits a broadcast message, and FIG. 5 is a relay of the broadcast message. FIG. 6 shows processing of a receiving node that receives a broadcast message.

  Here, all nodes including a relay node and a terminal can be considered as a node that transmits a broadcast message first. As a node that relays a broadcast message, a relay node having two or more set routes can be considered. As a receiving node that receives a broadcast message, all nodes including a relay node and a terminal can be considered.

  In the network as shown in FIG. 1, the wireless bridge 10 and each wireless base station 20 are the relay nodes described above. Each terminal 30 (30-1, 30-2) is a terminal that has only one route, and receives a message or transmits it for the first time.

  First, with reference to FIG. 4, the operation of a node that transmits a broadcast message according to this embodiment will be described.

  When the communication layer that performs control using the present embodiment is requested to transmit a message from the upper layer, the message body to be transmitted and the address of the transmission destination are supplied (step 401). The transmission destination is determined in step 402, and if the broadcast address is indicated, the process proceeds to step 406. Otherwise, the process proceeds to step 403.

  In step 403, it is determined whether or not the route to the transmission destination can be grasped, and if it can be determined, it is transmitted by unicast to the next node following the route (step 404). If the route is not known, it is necessary to transmit by broadcast. First, the destination address requested from the upper layer is set in the true destination field in the message format of FIG. 3 (step 405). This is a situation where the upper layer knows the destination address and the route cannot be recognized.For example, the upper layer stores the address because it has once communicated, but the route information has passed over time. There are cases where it has become invalid.

  On the other hand, if the transmission destination of the request from the upper layer is a broadcast address, the broadcast address is set as the true transmission destination (step 406). When the setting of the true transmission destination is completed, the own node is set as the true transmission source and the adjacent transmission source (step 407), and the process proceeds to step 408.

  In step 408, a broadcast address is set to the adjacent transmission destination of the message. After that, depending on the number of routes that the broadcast transmission node has, duplicate the message with the same message body, adjacent source, true destination, and true source, and set as the adjacent destination of each message. The address of the adjacent node in the route is set (steps 409 to 411).

  When there are a plurality of routes, the adjacent node of each route is set as the adjacent transmission destination. Therefore, as many messages having the same main body as the message having the broadcast address set as the adjacent transmission destination and the message having the unicast address set are generated by the number of routes of the node. For example, in the topology as shown in FIG. 1, when the terminal 30-1 broadcasts, the adjacent node on the predetermined route is the wireless base station 20-1, so the wireless base station 20-1 is set as the adjacent transmission destination. To do.

  And the message produced | generated by the above is transmitted (step 409). The above is the operation of the node that starts broadcasting according to the present embodiment.

  Next, the operation of the node that receives and relays the broadcast message according to the present embodiment will be described with reference to FIG.

  In the node that has received the message, the communication layer that controls the present invention receives a reception instruction from the lower layer (step 501). The adjacent transmission destination of the received message is confirmed (step 502). If it is a broadcast address, this message is discarded (step 503). If it is not a broadcast address, it is confirmed whether the adjacent transmission destination is its own node (step 504). If not, this message is discarded. Further, here, without being divided into step 502 and step 504, the adjacent transmission destination of the received message may be confirmed, and if it is a node other than the own node, it may be immediately discarded.

  If the adjacent transmission destination is the own node, it is confirmed whether the true transmission destination is broadcast (step 506). Otherwise, it is confirmed whether the true transmission destination is the own node (step 507). If the true transmission destination is the local node, a reception instruction is issued to the upper layer (step 509). If the true destination is not its own node, the presence / absence of a route to the address designated as the true destination is confirmed (step 508), and if there is a route, unicast communication is performed (step 510).

  If the route does not exist, the true transmission destination remains as the destination, and the process proceeds to step 512. In step 508, the route to the corresponding address is confirmed. If the route does not exist, a specific address is set as the true transmission destination, but the transmission is actually performed by broadcast. This enables delivery to a terminal whose position has not been recognized.

  If it is confirmed in step 506 that the true transmission destination is broadcast, the process proceeds to step 511. In step 511, an instruction to receive the broadcast message is given to the upper layer of communication. If the relay node that performs this control is a bridge that performs only relaying, there is a case where the upper layer does not exist. In this case, it is not necessary to notify the upper layer. Thereafter, the process proceeds to step 512.

  In step 512, the address of the own node is set as the adjacent transmission source address, and the process proceeds to step 513. In step 513, a broadcast address is set as the adjacent transmission destination address. After that, depending on the number of routes that the relay node has, the message with the same message body, adjacent sender, true destination, and true sender is duplicated and set to the adjacent destination of each message. The address of the adjacent node in the route is set (steps 514 to 516).

  However, of the adjacent nodes in the route, the node set as the adjacent transmission source of the received message is excluded. When there are a plurality of routes, the adjacent node of each route is set as the adjacent transmission destination. Accordingly, one message having the same main body, one message having a broadcast address set as an adjacent transmission destination, and one message having a unicast address set are generated by “the number of routes of a node—1”.

  For example, in the topology as shown in FIG. 1, when the radio base station 20-1 broadcasts a broadcast message received from the terminal 30-1, the adjacent nodes in the predetermined route are the radio base station 20-2 and the terminal 30-. However, since the adjacent transmission source of the received message is the terminal 30-1, the radio base station 20-2 is set as the adjacent transmission destination.

  Then, the message generated as described above is transmitted (step 517). For the true destination and true source of the message, the address set in the received message is not changed. The above is the operation of the node that relays the broadcast according to the present embodiment.

  Next, the operation of the receiving node according to the present embodiment will be described with reference to FIG.

  In the receiving node that has received the message, the communication layer that controls the present invention receives a reception instruction from the lower layer (step 601). The adjacent transmission destination of the received message is confirmed, and it is confirmed whether the message is addressed to the own node or broadcast (step 602). Otherwise, this message is discarded (step 603). If the message is addressed to the own node or broadcast, a reception instruction is issued to the upper layer (step 604).

  In this flow, only the adjacent transmission destination is confirmed, but it is also possible to confirm the true transmission destination in addition to the adjacent transmission destination, and execute step 604 only in the case of the own node or the broadcast address. As described above, when a broadcast address is set as an adjacent transmission destination, a broadcast message can be received even by a terminal that does not belong to a radio base station by performing reception processing.

  As described above, since the broadcast according to the present embodiment is performed by unicast along a set route and 1-hop broadcast at each node, the broadcast is correctly distributed to all nodes.

  In addition, since a message in which broadcast is set as an adjacent transmission destination is discarded on the receiving side, a broadcast storm that occurs when a broadcast message output from the own node returns does not occur.

  Furthermore, it is not necessary to provide an additional field in the message format used in the wireless multi-hop network, and it can be realized only by the control of each node.

  Next, a second embodiment of the present invention will be described with reference to the drawings.

  In the present embodiment, in addition to the field structure of the broadcast message of the first embodiment, a previous hop address is added as shown in FIG.

  Here, the previous hop address indicates the address of the node that transmitted the broadcast message that triggered the transmission when a node transmits the broadcast message. For example, in FIG. 1, when the radio base station 20-1 receives a broadcast message from the radio base station 20-2 and broadcasts the message, the previous hop address of the message to be transmitted is included in the radio base station. This is the address of the station 20-2. In the case of a node that transmits a broadcast message for the first time, the previous hop address does not exist. For example, in this case, the previous hop address may be used as the address of the own node.

  The operation of the node that starts broadcasting in this embodiment will be described with reference to the flowchart of FIG.

  The processing from step 801 to step 807 of the node that starts broadcasting in this embodiment is the same as the processing from step 401 to step 407 in the first embodiment, and the description thereof is omitted here.

  In step 808, a broadcast address is set as an adjacent transmission destination. Next, the address of the own node is set as the previous hop address (step 809). Since this is a node that starts broadcasting, there is virtually no previous hop address, so this field may be left empty. In this way, a broadcast message in which each field is set is transmitted (step 810).

  For example, in FIG. 1, when the terminal 30-1 starts broadcasting, the broadcast address is set as the true transmission destination, the address of the terminal 30-1 is set as the adjacent transmission source and the true transmission source, and the adjacent transmission destination is set. Is set to the broadcast address, the address of the terminal 30-1 is set to the address of the previous hop, and transmitted. The above is the operation of the node that starts broadcasting according to the present embodiment.

  Next, the operation of the node that relays the message in this embodiment will be described with reference to the flowchart of FIG.

  In the node that relays the message, when there is a reception instruction from a lower layer of the communication layer (step 901), it is determined whether the adjacent transmission source of the received message is an adjacent node of its own node in a preset route. (Step 902). If it is determined that the message is from a node other than the adjacent node, the message is discarded (step 903). If it is determined that the message is from an adjacent node, that is, a message from an upstream node or a downstream node of the own node, the process proceeds to step 904.

  In step 904, it is determined that the adjacent transmission destination of the received message is the local node or a broadcast address. If it is determined that the adjacent transmission destination is not the local node or the broadcast address, the message is discarded (step 905). If it is determined that the adjacent transmission destination is the local node or the broadcast address, the process proceeds to step 906, where it is determined whether the true transmission destination is the broadcast address.

  The processing from step 906 to step 911 is the same as the processing from step 506 to step 511 in the first embodiment, and the description thereof is omitted here.

  In step 912, it is determined whether the address set as the previous hop address is the address of the own node. If the previous hop address is the local node, the message is discarded (step 913). By discarding the message in step 913, it is possible to prevent a broadcast storm that is received again when the broadcast message transmitted by the own node is further transmitted by the adjacent node and is transmitted again. If it is determined that the previous hop address is not the local node, the adjacent transmission source of the received message is recorded, and the local node address is newly set as the adjacent transmission source (step 914).

  Next, a broadcast address is set as an adjacent transmission destination (step 915). Then, the adjacent transmission source of the received message recorded in step 914 is set as the previous hop address (step 916), and the message is transmitted (step 917). Do not change the true destination and source of the message.

  For example, in FIG. 1, the radio base station 20-1 that has received the broadcast message transmitted by the terminal 30-1 is broadcast because the terminal 30-1 is an adjacent node in the route and the adjacent transmission destination is broadcast. Decide what to do. Since the adjacent transmission source of the received message is the terminal 30-1, the terminal 30-1 is recorded as the previous hop address, and the address of the wireless base station 20-1 that is the own node is set as the adjacent transmission source. The broadcast address is set as the transmission destination, and the address of the terminal 30-1 recorded in the previous hop address is set and transmitted. The above is the operation of the node that relays the broadcast according to the present embodiment.

  The operation of the terminal in this embodiment is the same as that in the first embodiment, and the description thereof is omitted here.

  As described above, in this embodiment, in the relay node that relays the broadcast message, the source node of the broadcast message that triggered the transmission of the broadcast message is set as the previous hop address in the broadcast message. Thus, it is possible to prevent a broadcast storm in which the broadcast message transmitted by the own node receives a message broadcast again by the adjacent node and further broadcasts.

  In addition, since it is determined whether the received message is a message from an adjacent node on a preset route and broadcast messages from other than the route are discarded, no extra broadcast is generated.

  Further, by adding the address of the previous hop to the broadcast message field, it is possible to broadcast correctly without increasing the number of transmitted messages.

  Next, a third embodiment of the present invention will be described with reference to the drawings.

  In the present embodiment, a wireless multi-hop network having a tree structure in which a preset route has a single root node as a vertex is targeted. In the communication path of FIG. 1, the root node corresponds to the wireless bridge 10.

  In this embodiment, the broadcast message is unicast upstream along the route, reaches the root node once, and then broadcasts starting from the root node. Each relay node further broadcasts the broadcast message received from the adjacent node upstream of its own node in the route, but discards the broadcast message received from the downstream. The message used in the present embodiment has the same configuration as that shown in FIG. 3 as in the first embodiment.

  In the present embodiment, the processing of the broadcast transmission node that starts broadcasting will be described with reference to the flowchart of FIG. The processing from step 1001 to step 1007 in FIG. 10 is the same as the processing from step 401 to step 407 in the first embodiment, and the description thereof is omitted here.

  In step 1008, it is determined whether or not the own node is the root node. Since the root node does not have its own upstream node, it can be determined whether or not it is the root node.

  If it is a root node, the process proceeds to step 1009, a broadcast address is designated as an adjacent transmission destination, and a message is transmitted (step 1010). If it is determined that the own node is not the root node, the process proceeds to step 1011 where an upstream node is set as an adjacent transmission destination and a message is transmitted (step 1010).

  If the node that starts this broadcast transmission is a terminal, in step 1011 the address of the radio base station to which the node belongs is designated. For example, when the terminal 30-1 in FIG. 1 starts broadcasting, the broadcast address is set as the true transmission destination, the address of the own node is set as the true transmission source and the adjacent transmission source, and the radio base station 20-1 is set as the adjacent transmission destination. Then send. The above is the operation of the node that starts broadcasting according to the present embodiment.

  Next, processing of a node that relays a broadcast message according to this embodiment will be described with reference to the flowchart of FIG.

  In the relay node, the received message is provided from the lower layer (step 1101). It is determined whether the adjacent transmission source of the received message is an adjacent node (step 1102). If it is not an adjacent node, it is discarded (step 1103). If the adjacent transmission source is an adjacent node of the own node along the route, it is determined whether the adjacent transmission destination is the own node. If the adjacent transmission source is the own node, the process proceeds to Step 1107, and if not, the process proceeds to Step 1105 (Step 1104). ).

  For example, in the process when the radio base station 20-1 receives the broadcast message transmitted by the terminal 30-1 in FIG. 1, the terminal 30-1 is an adjacent node on the path for the radio base station 20-1, and Since the transmission destination is the radio base station 20-1, the process proceeds to step 1107.

  In step 1105, it is determined whether the adjacent transmission destination is a broadcast address (step 1105). If it is not broadcast, it is discarded (step 1106). If the adjacent transmission destination is broadcast, the process proceeds to step 1112.

  Here, the processing from step 1107 to step 1111 and step 1117 and the processing from step 1112 to step 1118 are the same as the processing from step 506 to step 511 in the first embodiment. Since the steps proceeding at 1109 and steps 1112 and 1114 are different from each other, the description thereof is omitted here.

  As described above, in the processing of steps 1117 and 1118, if the node performing this control has only a function like a bridge, there may be no upper layer. Absent.

  When steps 1117 and 1118 are completed, the process proceeds to steps 1119 and 1120, respectively. If the process proceeds to step 1119, it is determined whether the local node is the root node. If it is not the root node, the upstream node in the route is set as the adjacent transmission destination, the own node is set as the adjacent transmission source (step 1121), and the message is transmitted (step 1122). If it is the root node, a broadcast address is set for the adjacent transmission destination, its own node is set for the adjacent transmission source (step 1123), and a message is transmitted (step 1124).

  For the true source and true destination fields, it is not necessary to change the address set in the received message. For example, in FIG. 1, in the radio base station 20-1 that has received the broadcast message from the terminal 30-1, the radio base station 20-2 is set as the adjacent transmission destination, and the radio base station 20-1 that is the own node is set as the adjacent transmission source. Set the address of and send a message.

  When the processing proceeds to step 1120, it is determined whether the adjacent transmission source set in the received message is an upstream node of the own node in the route. If it is determined that the message is not from an upstream node, the received message is discarded (step 1125). If it is determined that the message is from an upstream node, the process proceeds to step 1126. In step 1126, a broadcast address is set in the adjacent transmission destination, the own node is set in the adjacent transmission source, and a message is transmitted (step 1127).

  For the true source and true destination fields, it is not necessary to change the address set in the received message. For example, in the radio base station 20-1 that has received the broadcast message from the radio base station 20-2 in FIG. 1, the radio base station 20-2 is an upstream node for the radio base station 20-1, so Is set to the broadcast address and the address of the wireless base station 20-1 that is the own node is set to the adjacent transmission source, and the message is transmitted. The above is the operation of the relay node of this embodiment.

  Since the operation of the receiving node in the present embodiment is the same as the operation of the receiving node in the first embodiment, a description thereof will be omitted.

  As described above, in this embodiment, a broadcast message is once unicast to a root node along a preset route, and broadcasted from the root node to the downstream. By further broadcasting only the broadcast message received from the node, the broadcast message is delivered to all the nodes and the occurrence of the broadcast storm can be prevented.

  Furthermore, it is not necessary to define a new message field, and the number of transmitted messages is not increased.

  Next, a fourth embodiment of the present invention will be described with reference to the drawings.

  In this embodiment, using the message format shown in FIG. 3 used in the first embodiment, each terminal always confirms not only the adjacent destination but also the true destination address, Broadcast message is unicast along the set route.

  The operation of the node that starts broadcasting in this embodiment will be described with reference to the flowchart of FIG.

  Here, the processing from step 1201 to step 1207 in the present embodiment is the same as the processing from step 401 to step 407 in the first embodiment, and therefore description thereof is omitted here.

  In step 1208, the address of the adjacent node in the route preset in the adjacent transmission destination is set, and the message is transmitted (step 1209). For example, when the terminal 30-1 in FIG. 1 starts broadcasting, the address of the radio base station 20-1 is set as an adjacent transmission destination and transmitted. When there are a plurality of adjacent nodes on the route, the address of each adjacent node is set and transmitted. The above is the operation of the node that starts broadcasting according to the present embodiment.

  Next, the operation of the relay node that relays messages according to the present embodiment will be described with reference to the flowchart of FIG.

  Here, the processing from step 1301 to step 1311 in the present embodiment is the same as the processing from step 501 to step 511 in the first embodiment, and therefore description thereof is omitted here.

  In step 1313, it is determined whether the own node is a terminal node in the route, that is, a node that does not have a route other than the route that received the message. For example, in FIG. 1, when the radio base station 20-3 receives a broadcast message from the radio base station 20-5, the radio base station 20-3 is a terminal node that has no route to the radio base station 20-5. Therefore, a broadcast address is set for the adjacent transmission destination.

  If it is a terminal node, a broadcast address is set in the adjacent transmission destination in step 1315, and the process proceeds to step 1316. If it is not a terminal node, an adjacent node other than the adjacent node set as the adjacent transmission source of the received message is set as an adjacent transmission destination (step 1314), and the process proceeds to step 1316.

  When there are a plurality of such adjacent nodes, each adjacent node is set as an adjacent transmission destination. For example, in FIG. 1, when the radio base station 20-5 receives a broadcast message from the radio base station 20-2, the adjacent nodes are the radio base stations 20-2 and 20-3 and the radio bridge 10, but the received message Since the address of the radio base station 20-2 is set in the adjacent transmission source of the message, the address of the radio base station 20-3 and the radio bridge 10 is set as the adjacent transmission destination except for the radio base station 20-2. Two are generated.

  After setting the adjacent transmission destination, in step 1316, the address of the own node is set as the adjacent transmission source, and the message is transmitted (step 1317). However, as for the true destination, the true source, and the message body, the received message is used as it is. The above is the operation of the relay node of this embodiment.

  Next, the operation of the terminal that receives the broadcast message of this embodiment will be described with reference to the flowchart of FIG.

  When the communication layer performing this control receives a reception instruction from the lower layer (step 1401), it is determined whether the true transmission destination is a broadcast address (step 1402). If the true destination is not a broadcast address, normal reception processing is performed. For example, when the adjacent transmission destination is the local node or broadcast address, the normal transmission processing confirms the true transmission destination. If the real transmission destination is the local node, the reception instruction is given to the upper layer of communication. Is to supply.

  If it is determined that the true transmission destination is a broadcast address, it is determined in step 1404 whether the affiliated radio base station has already been determined. It can be confirmed that the wireless base station is not set in the terminal by the absence of the route. If the assigned radio base station has not been determined, the process proceeds to step 1407, and if it has been determined, the process proceeds to step 1405.

  For example, in FIG. 1, the terminal 30-3 does not belong to any radio base station. At this time, the broadcast started by the terminal 30-1 is received by the radio base station 20-3 via the radio base stations 20-1, 20-2, and 20-5, and the radio base station 20-3 is adjacent to the radio base station 20-3. Send a message with a broadcast address set for the destination and the true destination. The terminal 30-3 that has received this message issues a reception instruction to the upper layer of communication because the true transmission destination is the broadcast address and the associated radio base station has not been determined. The above is the operation of the terminal according to the present embodiment.

  In this embodiment, a broadcast message is delivered by unicast to a node whose route is known along a preset route, and a terminal whose location is not registered is always a true destination address. In the case of a broadcast address, reception processing is performed, so that a correct broadcast is possible without generating a broadcast storm.

  Further, it is not necessary to newly define a message field, and the number of transmitted messages is not increased.

  Note that the broadcast system according to each of the above embodiments realizes functions such as transmission, relay, and reception of broadcast messages in the wireless bridge 10, the wireless base station 20, and the terminal 30, and other functions in hardware. As described above, a computer program having each function can be realized by being loaded into a memory of a computer processing apparatus. This computer program is stored in a magnetic disk, semiconductor memory or other recording medium. Each function described above is realized by being loaded from the recording medium into the computer processing apparatus and controlling the operation of the computer processing apparatus.

  Although the present invention has been described with reference to the preferred embodiments and examples, the present invention is not necessarily limited to the above-described embodiments and examples, and various modifications can be made within the scope of the technical idea. Can be implemented.

It is a figure which shows an example of the network structure for describing embodiment of this invention. It is a block diagram which shows an example of the apparatus structure of the network for describing embodiment of this invention. It is a figure which shows an example of the message format in this invention. It is a flowchart for demonstrating the process of the broadcast transmission node by the 1st Embodiment of this invention. It is a flowchart for demonstrating the process of the broadcast relay node by the 1st Embodiment of this invention. It is a flowchart for demonstrating the process of the receiving node by the 1st Embodiment of this invention. It is a figure which shows an example of the message format of the 2nd Embodiment of this invention. It is a flowchart for demonstrating the process of the broadcast transmission node by the 2nd Embodiment of this invention. It is a flowchart for demonstrating the process of the broadcast relay node by the 2nd Embodiment of this invention. It is a flowchart for demonstrating the process of the broadcast transmission node by the 3rd Embodiment of this invention. It is a flowchart for demonstrating the process of the broadcast relay node by the 3rd Embodiment of this invention. It is a flowchart for demonstrating the process of the broadcast transmission node by the 4th Embodiment of this invention. It is a flowchart for demonstrating the process of the broadcast relay node by the 4th Embodiment of this invention. It is a flowchart for demonstrating the process of the terminal by the 4th Embodiment of this invention. It is a figure for demonstrating the broadcast using a radio | wireless.

Explanation of symbols

10 wireless bridge 20, 20-1, 20-2, 20-3, 20-4, 20-5 wireless base station 30, 30-1, 30-2, 30-3 terminal 10a bridge 20-1a, 20-2a , 20-3a, 20-4a radio base station 30a terminal

Claims (4)

In a broadcast system that broadcasts messages on a wireless network,
Each node that sends, receives, and relays messages
For messages communicated with other nodes, a true destination address indicating the final destination of the message, a true source address indicating the initial source of the message, and an adjacent node Means for transmitting by adding the data of the adjacent transmission destination address indicating the transmission destination of the message in the transfer between and the data of the adjacent transmission source address indicating the transmission source of the message in the transfer between adjacent nodes to the message;
Means for transmitting a broadcast message to adjacent nodes using unicast communication along a preset path;
A mobile terminal that receives the broadcast message is:
When receiving a message in which a broadcast address is set as the true destination address, if there is a radio base station to which the mobile terminal currently belongs in the communication area, the adjacent destination address is set to the own node. A broadcast system that performs the message reception process only when set, and always performs the message reception process when there is no radio base station to which the mobile terminal belongs. In a mobile terminal that receives a broadcast message transmitted over a wireless network,
A true destination address indicating the final destination of the message, a true source address indicating the first source of the message, and an adjacent destination indicating the destination of the message in the transfer between adjacent nodes Means for receiving a message transmitted by adding an address and data of an adjacent source address indicating the source of the message in the transfer between adjacent nodes;
When receiving a message in which a broadcast address is set as the true destination address, if there is a radio base station to which the mobile terminal currently belongs in the communication area, the adjacent destination address is set to the own node. A mobile unit that performs reception processing of the message only when set, and has means for always performing reception processing of the message when there is no radio base station to which the mobile terminal belongs Terminal. In a broadcast method for broadcasting a message on a wireless network,
Each node that sends, receives, and relays messages
For messages communicated with other nodes, a true destination address indicating the final destination of the message, a true source address indicating the initial source of the message, and an adjacent node A step of transmitting the adjacent transmission destination address indicating the transmission destination of the message in the transfer between and the data of the adjacent transmission source address indicating the transmission source of the message in the transfer between the adjacent nodes by adding to the message;
Transmitting a broadcast message to adjacent nodes using unicast communication along a preset path;
A mobile terminal that receives the broadcast message is:
When receiving a message in which a broadcast address is set as the true destination address, if there is a radio base station to which the mobile terminal currently belongs in the communication area, the adjacent destination address is set to the own node. A broadcast method comprising: performing reception processing of the message only when set, and performing reception processing of the message whenever there is no radio base station to which the mobile terminal belongs . In a broadcast program that broadcasts messages on a wireless network,
To each node that sends / receives / relays messages
For messages communicated with other nodes, a true destination address indicating the final destination of the message, a true source address indicating the initial source of the message, and an adjacent node A process of adding data of an adjacent transmission destination address indicating a transmission destination of the message in the transfer between and an adjacent transmission source address indicating a transmission source of the message in the transfer between adjacent nodes to the message;
A process of transmitting a broadcast message to an adjacent node using unicast communication along a preset route,
To a mobile terminal that receives the broadcast message,
When receiving a message in which a broadcast address is set as the true destination address, if there is a radio base station to which the mobile terminal currently belongs in the communication area, the adjacent destination address is set to the own node. A broadcast characterized in that the reception process of the message is performed only when set, and the process of receiving the message is always executed when there is no radio base station to which the mobile terminal belongs program.

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