JP2007089182A - Method and apparatus for high-speed path establishment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the high-speed path establishment method capable of establishing a path at a high speed. <P>SOLUTION: The method includes: a step A in which a destination node receives a path request packet and the path information attached to the path request packet received from each path is encapsulated in one path response packet corresponding to a source node of the path request packet; and a step B in which it is judged whether the path response packet can be transmitted, a packet to which a path response message is attached is transmitted to the source node via an intermediate node when it can be transmitted and a process is returned to the step A when it can not be transmitted. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to routing technology, and more particularly, to a method and apparatus for establishing a high-speed route.

  Common mobile networks usually appear in the form of cellular networks or wireless LANs. In a cellular network, communication between mobile terminals must be completed by relaying between a base station and a mobile switch. In a wireless LAN, a mobile terminal is connected to an existing fixed network via a wireless access point. At the same time, a large number of new mobile communication technologies such as Bluetooth (Bluetooth) and home wireless network (HomeRF) are appearing. These mobile networks and wireless communication technologies are supplements and developments to fixed networks, as well as requiring fixed infrastructure support and generally adopt a centralized control scheme. However, in some special application environments or emergencies, mobile communication networks that require fixed infrastructure support can no longer meet the needs of the application environment. For example, when a unit deploys and promotes quickly on the battlefield, searches and rescues after a natural disaster such as an earthquake, or scientific considerations in the field. Therefore, in these application situations, there is an urgent need for a mobile communication network that does not depend on a fixed infrastructure and can be arranged at high speed and flexibly. Ad hoc networks have been created to meet these special application needs. An ad hoc network is a multi-hop, temporary autonomous network without a base station, which is composed of a set of mobile nodes equipped with wireless handsets. In the ad hoc network, each mobile node has a router function. Hereinafter, a mobile node in the Ad hoc network is abbreviated as a node.

  The Ad hoc network has many advantages. First, the network's self-organizing features offer the possibility of deploying the network at low cost and at high speed. Second, the multi-hop and intermediate node forwarding characteristics reduce the transmission range of each terminal without reducing the network coverage, thereby reducing the design difficulty of the antenna and associated transmit / receive components. At the same time, the power consumption of the equipment is reduced, and the possibility is provided for miniaturization of the mobile terminal and low power consumption. In addition, network stability, resistance to destruction, etc. meet the needs of some specific applications. Therefore, the Ad hoc network can be widely applied to applications such as military, emergency repair and victim relief, conferences, and expansion of coverage of existing cellular mobile communication systems.

  Compared to traditional communication networks that require fixed infrastructure support, Ad hoc networks have no centralized control station, self-organization, dynamically changing network topology, mobile terminal localization, poor It also has significant features such as security and multi-hop routing. Among them, multi-hop routing is generated by the limitation of node transmission power and the finite node coverage. Here, when a node needs to communicate with a node outside its coverage range, transfer of another node in the network is necessary. A node that participates in forwarding is called an intermediate node, that is, the intermediate node needs to be able to provide a routing function. Note that other nodes in the network within the node cover range are referred to as adjacent nodes of the node. Any node in the Ad hoc network can communicate directly with its neighbors and does not require intermediate node forwarding.

  Routing is the most important issue in Ad hoc networks, and to solve the problem, the IETF has specially designated the Mobile Ad hoc Networks (MANET) working group to study routing protocols in wireless Ad hoc networks. It was established. Here, the most representative protocols are the Dynamic Source Routing (DSR) protocol and the Ad hoc On Demand Distance Vector Routing (AODV) protocol.

  FIG. 1 is a configuration diagram of an apparatus that realizes path establishment in an Ad hoc network node. The establishment of a route can be realized through the device. Specifically, the apparatus includes a path buffer unit 11, a network layer data processing unit 12, a media access control (MAC) layer data processing unit 13, a MAC layer data storage unit 14, and a transmission unit 15. It has a receiving unit 16 and six functional units. Among them, the route buffer unit 11 stores routing related information, for example, a request route table, a transfer route table, acquired route information, and the like. The network layer data processing unit 12 searches the path for the received data message, divides the data message into packets of a certain length, encapsulates the packet, and forwards the packet from the MAC layer to the upper layer. The MAC layer data processing unit 13 adds a control message for identifying the MAC layer to the packet header (head), and performs media access control and packet transmission. The MAC layer data storage unit 14 stores a packet to be transmitted and transmits the stored data by adopting a first-in first-out (FIFO) principle. The transmission unit 15 transmits a packet via a wireless broadcast channel. The receiving unit 16 receives data transmitted from the wireless broadcast channel.

  In an ad hoc network, a network node accesses a wireless broadcast channel based on a carrier sense multiple access / collision detected (CSMA / CD) protocol generally defined in 802.11. The network node obtains a packet to be transmitted to the network node by transmitting the packet to the channel in a broadcast format and continuously sensing the packet of the wireless broadcast channel.

  In the data transmission process, the network layer data processing unit 12 receives a user data message from an upper layer and encapsulates the user data message by dividing it into packets of a certain length. In addition, based on the route information stored in the route buffer unit 11, the route is searched for the user data message. The network layer data processing unit 12 sends the packet to the MAC layer data processing unit 13 for encapsulation, and sends the processed packet from the MAC layer data processing unit 13 to the MAC layer data storage unit 14 for storage. . When the MAC layer data processing unit 13 detects that the wireless broadcast channel satisfies the channel access condition, the MAC layer data processing unit 13 transmits the packet stored in the MAC layer data storage unit 14 through the transmission unit 15 according to the first-in first-out principle. .

  In the data reception process, the MAC layer data processing unit 13 senses the packet transmitted from the reception unit 16, decapsulates the packet transmitted to this node, and transmits the unencapsulated packet to the network layer data processing unit 12. Send to and process. The network layer data processing unit 12 processes the received packet, and transfers the packet or transmits it to the upper layer for processing according to the route information attached to the packet.

  Here, the basic process of establishing a route is introduced using DSR as an example. Among them, all processing of control messages related to routing is performed by the network layer data processing unit 12.

  When the network layer data processing unit 12 in the source node receives the data message transmitted from the upper layer, it first checks in the path buffer unit 11 whether there is a path to the destination node. If there is, the data message is transmitted using the route in the transmission buffer. If not, a route search process for searching for a destination node from the source node is started, and one route request (RREQ) packet is broadcast. The transmission buffer in the text is the MAC layer data storage unit 14.

  After the intermediate node receives the RREQ packet, the network layer data processing unit 12 first checks whether the same RREQ packet has been received before that. If it has been received, the currently received RREQ packet is a duplicate packet, and the currently received RREQ packet is deleted. If the same RREQ packet has not been received, it is checked whether there is a valid path to the destination node in the route buffer unit 11 of the intermediate node. If there is, the route response (RREP) packet is returned to the source node. The route information recorded in the currently received RREQ packet is attached to the RREP packet. Otherwise, the intermediate node adds its route information to the route record (RECORD) in the RREQ packet, and then broadcasts the RREQ packet.

  Before the destination node receives the RREQ packet sent from the source node, the RREQ packet may have already passed one or more intermediate nodes, and the intermediate node is in the RREQ packet forwarding process. All of my route information was added to the RREQ packet.

  When the destination node receives the RREQ packet, the destination node responds to the source node with an RREP packet with path information from the source node to the destination node. When responding with an RREP packet, the destination node first checks if there is a path in the path buffer unit 11 to the source node. If there is, the RREP packet is transferred using the route obtained by the search. If not, further check whether the link is symmetric, and if the link is symmetric, use the path recorded in the currently received RREQ packet to reply the RREP packet in the reverse direction to the source node. If the link is not symmetric, the path search process is started from the destination node to the source node corresponding to the RREQ packet currently received from the destination node. The specific process of route search is that the destination node broadcasts a new RREQ packet for searching for the source node, and RREP information that is sent back from the destination node to the source node is attached to the RREQ packet. Here, whether or not the rings are symmetrical refers to whether or not the link channel quality is the same. In general, the RREQ packet from the source node reaches the destination node through a plurality of paths, and each time the destination node receives one RREQ packet, one RREP packet or RREP message corresponding to the received RREQ packet It responds to the source node with the RREQ packet marked with. Therefore, on the receiving side, the source node also receives RREP packets from a plurality of paths or RREQ packets with RREP messages.

  The intermediate node is a process of transferring a packet transmitted from the destination node to the source node to the next hop node, and uses the route information recorded in the received RREP packet or RREQ packet, and uses its own route buffer unit 11. Update.

  When the source node receives the RREP packet or the RREQ packet to which the RREP message is attached, the source node acquires route information to the destination node from the received RREP packet or the RREP message attached to the RREQ packet. When the source node receives RREP packets from a plurality of paths, the source node can acquire a plurality of routes to the destination node.

  AODV, like DSR, has an “on demand” feature and searches for routes “on demand” through a similar discovery process. AODV uses a sequence number coding scheme to ensure that all links are loop-free, with intermediate nodes responding only to the latest message, and to each node the IP address of the source node, And the latest sequence number of the destination node known to the source node are included. In the RREQ packet forwarding process, the intermediate node establishes one reverse path by recording the address one hop before the received RREQ packet in its routing table. If the destination node or an intermediate node having a route to the destination node receives the RREQ packet and the sequence number of the received RREQ packet is equal to or greater than the sequence number included in the RREQ packet, the destination node or intermediate node The packet is returned to the source node, and unicast is performed along the reverse path until reaching the source node that started the route search. AODV applies only in the case of link symmetry, because RREP packets are forwarded along the path established by the RREQ packet.

  In the process of establishing a route, all transmissions of packets in the ad hoc network are performed through a broadcast method. In addition, the time to transmit the RREQ packet or RREP packet of the source node, intermediate node and destination node and the time to transmit in the space are relatively concentrated, so a large number of RREP packets and RREQ packet collisions occur in the MAC layer However, the transmission again due to the collision has a great influence on the path establishment speed. In addition, since the number of packets related to route control in the Ad hoc network is very large, the route establishment speed is further reduced.

  The present invention has been made in view of the above, and an object of the present invention is to provide a high-speed route establishment method capable of establishing a route at high speed.

  Another object of the present invention is to provide an apparatus for establishing a high-speed route that can establish a route at high speed.

  In order to achieve the above object, the technical solution of the present invention is realized as follows.

A fast route establishment method,
The destination node receives the route request packet and encapsulates the route information attached to the route request packet received from each route into one route response packet corresponding to the source node of the route request packet. ,
Determine whether the route response packet can be transmitted, and if so, send the packet with the route response message to the source node via the intermediate node; otherwise, return to step A, step B;
Including this method.

  Here, the packet to which the route response message is attached in step B is a route response packet or a route request packet to which a route response message is attached.

  Here, the determination in step B is to execute step A and determine in real time.

  The method further includes providing a timer and setting a time keeping time. In step A, the destination node starts the timer after receiving the first route request packet of the source node.

  Determining whether or not transmission is possible in step B is determining whether or not the timer has timed out, and transmitting when the time is up, otherwise transmitting is not possible.

  Here, the determination in step B is to execute step A and determine in real time.

In addition, each node participating in the route establishment before sending a packet,
It is determined whether or not the received packet is a routing packet. If so, the packet is stored in the transmission buffer, and all the routing control packets waiting to be transmitted are preferentially transmitted. It further includes storing in the transmission buffer and transmitting normally.

  The method further includes providing a timer and a counter, and setting a time count and a count value. In step A, the destination node receives the first route request packet of the source node, Start the counter.

  Determining whether or not the transmission is possible in step B is to determine whether or not the counter has reached a set count value, and if so, it can be transmitted, otherwise it cannot be transmitted.

In addition, before each node participating in route establishment transmits a packet, the method
It is determined whether or not the received packet is a routing packet. If so, the packet is stored in the transmission buffer, and all the routing control packets waiting to be transmitted are preferentially transmitted. It further includes storing in the transmission buffer and transmitting normally.

The method further includes providing a timer and a counter, and setting a time count and a count value. In step A, after the destination node receives the first route request packet of the source node, the timer and counter are set. Further starting at the same time,
Determining whether the transmission is possible in step B determines whether the timer has timed out or if the counter has reached a count, if so, it can be transmitted, otherwise it cannot be transmitted. That is.

  Here, determining whether or not the timer has expired in step B is to execute step A and determine in real time whether or not the timer has expired.

Here, the packet with a route response message transmitted from the intermediate node to the source node is a route request packet with a route response message, and a route request packet with a route response message attached from the intermediate node. Is specifically sent to the source node
Step B11 in which the intermediate node senses the broadcast channel and acquires a route request packet transmitted from the adjacent node;
Step B12 in which the intermediate node searches for a packet waiting for its current transmission and deletes the route response message attached to the same route request packet as the packet acquired in Step B11.

  Here, the acquired route request packet transmitted from the adjacent node in step B11 is a route request packet to which a route response message is attached.

Here, the packet with the route response message transmitted from the intermediate node to the source node is a route response packet, and the transmission of the route response packet from the intermediate node to the source node is specifically,
Step B21 in which the intermediate node senses the broadcast channel and obtains a route response packet transmitted from the adjacent node;
The intermediate node searches for a packet waiting for its current transmission, and deletes the same route response packet as the packet acquired in step B21.

In addition, before each node participating in route establishment transmits a packet,
It is determined whether or not the received packet is a routing packet. If so, the packet is stored in the transmission buffer, and all the routing control packets waiting for transmission are sequentially transmitted. Otherwise, The method further includes storing the packet in a transmission buffer and transmitting the packet normally.

A path buffer unit, a network layer data processing unit, a MAC layer data processing unit, a MAC layer data storage unit, a transmission unit and a reception unit;
The network layer data processing unit receives the upper layer data message, transmits the processed data and the generated routing control packet to the MAC layer data processing unit to be processed,
The path buffer unit provides a search for path information for a network layer data processing unit;
The MAC layer data processing unit stores the processed packet in the MAC layer data storage unit and waits for transmission,
When the MAC layer data storage unit detects that a broadcast channel is available, it transmits through the transmission unit;
The receiving unit transmits a message sensed from the broadcast channel to the MAC layer data processing unit for processing.
A high-speed route establishment device,
The network layer data processing unit further includes a transmission trigger, the network layer data processing unit receives a packet from the MAC layer data processing unit, and transmits route information attached to one or more route request packets. When encapsulated in one route response packet and the first route request packet from the source node is received, the transmission trigger is started and the packet with the route response message is MAC layer data by triggering the transmission trigger. To the processing unit,
The transmission trigger triggers the network layer data processing unit to transmit a packet with a route response message.

  Here, the transmission trigger is a timer or a counter.

  Here, the packet to which the route response message is attached is a route response packet or a route request packet to which the route response message is attached. The apparatus further comprises a data type control unit, the data type control unit checks a packet transmitted from the receiving unit to the MAC layer data processing unit, obtains a route response packet, and is the same as the obtained route response packet The route response packet is deleted, or / and the route request packet attached with the route response message is acquired, and the route response message attached to the same route request packet as the acquired route request packet is deleted.

  In addition, the apparatus further includes a priority control unit that performs control so that the route control message is sequentially preferentially transmitted by the MAC layer data storage unit.

The packet with the route response message is a route response packet or a route request packet with a route response message, and the device checks the packet transmitted from the receiving unit to the MAC layer data processing unit. The route response packet is acquired, the same route response packet as the acquired route response packet is deleted, and / or the route request packet with the route response message is acquired, and the route request packet is the same as the acquired route request packet. A data type control unit for deleting the attached route response message, and
A priority control unit that controls the MAC layer data storage unit so that the route control messages are sequentially preferentially transmitted.

  The high-speed route path establishment method and apparatus provided in the present invention waits for a certain time after the destination node receives the first route request packet from the source node or waits for a certain number of route request packets. Waiting for collection, then encapsulating the route information attached to the route request packet received within the waiting time or a certain number of collected route request packets into the same RREP packet and returning it to the source node, Not all RREQ packets are answered with RREP packets. Thus, the number of destination nodes responding with RREQ packets is reduced, and the number of routing packets broadcast on the wireless broadcast channel is reduced. Therefore, collisions at the MAC layer due to routing packets are also reduced, increasing the speed of path establishment.

  In addition, the present invention can add a node sensing process to the MAC layer. When a node senses that its neighboring node is transmitting the same RREP packet as its transmission buffer or RREQ packet with an RREP message, it does not forward the RREP packet in its transmission buffer. Alternatively, the RREP message attached to the RREQ packet is deleted. Thereby, the number or length of route control packets is reduced, the probability of occurrence of collisions at the MAC layer due to the packets is reduced, and the number of transmissions is reduced again to increase the speed of route establishment. At the same time, the present invention fully implements backward compatibility in the route establishment process, and can realize a faster route establishment process without increasing any hardware cost.

  In the present invention, each node adjusts the position of the route control packet in the transmission buffer with respect to the route control packet waiting for transmission, so that the route control packet is transmitted with priority over other packets, and the speed of route establishment is increased. It is even higher.

  The main idea of the present invention is to encapsulate the route information attached to one or more route request packets received by the destination node into one route response packet and then send it to the source node. . That is, when the destination node receives the first RREQ packet from a certain source node, it does not immediately return the RREP packet corresponding to the source node, but one or more RREQ packets from the same source node. Encapsulate the route information attached to one or more RREQ packets into a single RREP packet, and wait for a certain time or / and a certain number. Alternatively, an RREQ packet with an RREP message is transmitted to the source node. Here, being able to transmit means that the provided timer has timed up or the provided counter has reached a set value. The RREQ packet with the RREP packet and the RREP message attached may be collectively referred to as a packet with the RREP message attached.

  The method according to the present invention is applied to a routing protocol in an ad hoc network such as DSR or AODV. When the route information to the destination node is stored in the intermediate node in the route establishment process, the RREP packet is directly returned to the source node according to the processing flow of the prior art. The processing method of the present invention is limited to the case where the destination node receives the RREQ packet and the received RREQ packet is transferred via at least one intermediate node.

  In order to implement the method according to the present invention, transmission triggers, for example, counters and / or timers, are respectively transmitted to different source nodes corresponding to the received RREQ packet, and the network layer data processing of the path establishment realizing device in the prior art Must be set in unit 12. When a RREQ packet is received, an RREP packet corresponding to the received RREQ is not returned immediately, but when a condition is satisfied, an RREP packet or RREP message encapsulating multiple route information is attached by a transmission trigger. The RREQ packet is triggered to be returned from the destination node to the source node. Here, triggering when the condition is satisfied is to trigger when the timer expires or the counter reaches a set value.

  FIG. 2 shows a specific implementation process of the method of the present invention. The process shown in FIG. 2 starts when the destination node receives the RREQ packet, ends until the source node receives the packet with the RREP message sent back from the destination node, and the source node is the destination node. The process of sending RREQ packets to was omitted. Among them, the process in which the source node transmits the RREQ packet and the process in which the intermediate node processes the RREQ packet is the same as in the prior art and will not be described in detail here. The process shown in FIG. 2 introduces an example where the destination node waits for a certain number of RREQ packets. That is, when the counter reaches a set value, a packet with an RREP message is transmitted from the destination node to the source node. The specific process of the present embodiment is as follows.

  In steps 201 to 202, after the RREQ packet reaches the destination node, the destination node first acquires the source node message attached to the currently received RREQ packet. Here, it is assumed that the source node is known as the source node A based on the acquired source node message. Next, it is determined whether or not the RREQ packet corresponding to the source node A has been received. If the destination node has not previously received the RREQ packet corresponding to the source node A, that is, if the currently received RREQ packet is the first RREQ packet from the source node A, the process proceeds to step 203. Otherwise, it represents that the destination node has already received the RREQ packet from the same source node A before receiving the current RREQ packet, and the process proceeds to step 204.

  In step 203, one counter for the source node A is set in the network layer data processing unit 12, the counter is started, and the count value of the counter is set. At the same time, the destination node generates an RREP packet corresponding to source node A.

  In step 204, the destination node acquires route information from the source node to the destination node attached to the RREQ packet, adds the acquired route information to the RREP packet corresponding to the currently received RREQ packet, and the RREQ packet 1 is added to the counter of the source node corresponding to.

  In step 205, it is determined whether the destination node can send the RREP packet. Here, it is to determine whether or not the count value of the counter of the source node corresponding to the currently received RREQ packet has exceeded the set count value, and if so, proceed to Step 206, otherwise proceed to Step 201. Return.

  In step 206, the destination node searches its route buffer unit 11 for a route to the source node corresponding to the currently received RREQ packet, and if so, proceeds to step 207; Proceed to step 208.

  In step 207, the destination node takes out the RREP packet corresponding to the currently received RREQ packet, and encapsulates one or more route information according to the path to the source node recorded in the route buffer unit 11. To the source node via the intermediate node, and proceeds to step 211.

  In step 208, the destination node determines whether the link in the network is a symmetric link, and if so, proceeds to step 209, otherwise proceeds to step 210.

  In step 209, if the link is symmetric, the destination node retrieves the RREP packet corresponding to the currently received RREQ packet, and uses the path information recorded in the currently received RREQ packet to convert the RREP packet to the intermediate node. And return to the source node in the reverse direction, and go to step 211.

  In step 210, if the link is not symmetric, the destination node initiates a route search process for the source node and broadcasts a new RREQ packet. An RREP message is attached to the broadcast RREQ packet, and one or a plurality of pieces of route information are attached to the RREP message. By broadcasting and transmitting a new RREQ packet, a plurality of RREQ packets encapsulating route information from the source node to the destination node are returned to the source node via the intermediate node, and the process proceeds to step 211.

  In step 211, after receiving the RREP packet returned from the destination node or the RREQ packet with the RREP message attached thereto, the intermediate node processes the received RREP packet or RREQ packet according to the prior art. The specific process is as follows. If it is the RREP packet received by the intermediate node, the intermediate node first updates the route information in its route buffer unit 11 using the route information attached to the RREP packet, and then Forward the received RREP packet to the next hop node. If the intermediate node received is an RREQ packet that is sent from the destination node and searches for the source node, the received RREQ packet is similarly processed according to the method of processing the RREQ packet in the prior art, and the RREQ packet The route information in its own route buffer unit 11 is updated based on the route information in the RREP message attached to.

  In step 212, when the source node receives the RREP packet sent back from the destination node, it obtains the route information to the destination node attached to the RREP packet, and based on the route information attached to the RREP packet The path buffer unit 11 is updated. When the source node receives the RREQ packet for searching the source node, which is started from the destination node, the source node obtains the RREP message attached to the RREQ packet, and further, from the source node by the attached RREP message. The route information to the destination node is acquired, and the route information in its own route buffer unit 11 is updated using the route information attached to the RREP message. At the same time, using the returned route information, an RREP packet with route information from the destination node to the source node is returned to the destination node. The destination node acquires the route information to the source node by receiving the RREP packet returned from the source node.

  Thus far, the high-speed path establishment process in the present invention is completed.

  In addition, in step 203, that is, after determining that the currently received RREQ packet is the first RREQ packet from the source node, the destination node starts with providing a counter for the source node, A timer for the source node A may be provided and started. At the same time, a time is set and an RREP packet corresponding to the source node A is generated. Here, similarly, it is assumed that the currently received RREQ packet is from the source node A. When providing a timer, the destination node can establish a route according to a process as shown in FIG. 2, and can also perform the route establishment process through the following method. That is, the destination node senses the timer in real time, and when the RREQ packet corresponding to the source node A reaches the destination node in the process where the timer time has not reached the time keeping time, the destination node receives the RREQ packet currently received. Is encapsulated in the RREP packet corresponding to the source node A. When the timer reaches the timed time, the process proceeds to the process of searching for a route to the source node A in Step 206 regardless of which step of the route establishment process the destination node is in.

  In the present invention, in step 203, that is, after determining that the currently received RREQ packet is the first RREQ packet from the source node A, the destination node simultaneously provides a counter and timer for the source node A. The RREP packet corresponding to the source node can be generated by setting the count value and time count. When either the timer or counter reaches the set value, the process proceeds to the process of searching for a route to the source node in step 206. When the RREQ packet corresponding to the source node A reaches the destination node in a process where the timers and counters have not reached the set values, the destination node displays the route information attached to the currently received RREQ packet. And encapsulating in the RREP packet corresponding to the source node A.

  In the present invention, the timer or counter and the corresponding timekeeping time or count value are set after the first RREQ packet from the source node is received, and when the path establishment process cannot be started, the node May be set in. After receiving the first RREQ packet from the source node, the destination node starts a corresponding timer or / and counter for the source node.

  Based on the needs of the network environment, the same or different values can be set for counters or timers for different source nodes. Here, the destination node may provide a counter or timer and set a count value or time count. After network initialization, the count value or time count is determined in advance and the counter or timer is set. The value set in advance may be directly arranged. The count value or time count is closely related to the network load, topology structure, and the like.

  The count value of the counter may be one or plural. When specifically setting, the average value or maximum value of the number of paths that can exist is estimated in advance based on the topology structure of the network and the operation status of the network, and a specific count value is calculated based on this average value or maximum value. Can be set.

  The time measured by the timer can be set based on the network topology structure and the network load. For example, when the distribution of nodes in the network is relatively uniform, if the time difference for the RREQ packet to reach the destination node through a plurality of paths is relatively small, the waiting time of the destination node is also relatively short. You can set a relatively short timekeeping time. When the path through which the RREQ packet passes is large, the time difference between the RREQ packet and the destination node also becomes relatively large. In this case, the destination node sets a relatively short time and either returns the packet with the RREP message immediately or waits continuously and sets a relatively long wait time. After collecting the RREP packets, it is necessary to determine whether to return the packet with the RREP message. At this time, the destination node needs to make a decision based on a request for the quality of the route and a request for the effective path.

  In addition, the specific size of the set value can be determined based on experience values and data accumulated in experiments over a long period of time. For example, when an application layer requests that a data message of 5000 bytes to 10000 bytes per second be averaged for a scene in which 50 nodes are randomly distributed at 10 km * 10 km, the waiting time is 0.05 S to 0.2 S Experiments have shown that setting S to be relatively reasonable. Therefore, a large amount of experiments are conducted, the conditions of the experiment and the results obtained in the experiment are created in a table and searched when necessary, and at the same time, based on experience, the condition of the experience value and the magnitude of the experience value You can create it in a table and search it when you need it.

  In the present invention, when the RREP packet is returned from the destination node to the source node, the destination node encapsulates a plurality of route information into one RREP packet, and the one RREP packet is sourced through one or a plurality of paths. Since the reply is made to the node, all the RREP packets transferred by the intermediate node are the same. If even one RREP packet can reach the source node, the source node can acquire all paths to the destination node attached to the RREQ packet received by the destination node. Similarly, when it is an RREQ packet that is sent from the destination node to the source node, the RREP message attached to the RREQ packet is all the same, and the source node even has one RREQ packet attached with the RREP message. If received, all paths up to the destination node can be acquired. In addition, since all the nodes in the Ad hoc network communicate through the wireless broadcast channel, the nodes constantly perform channel sensing. Therefore, in step 211 of the specific implementation process in the present invention, the intermediate node transfers the RREP packet sent back from the destination node to the source node, or senses the channel when transmitting the RREQ packet to the source node. The packet transmission message of the adjacent node can be acquired.

  If there is an adjacent node returning an RREP packet around the intermediate node, the intermediate node is the same as the sensed RREP packet being transmitted to the adjacent node in its own MAC layer data storage unit 14. Delete RREP packets. When the adjacent node transmits the RREQ packet, the intermediate node deletes the RREP message attached to the same RREQ packet as the sensed RREQ packet. Thus, by reducing the number of times the intermediate node transmits the RREP packet, or reducing the length of the transmitted RREQ packet, the collision at the MAC layer due to the packet is reduced, and the path establishment speed is increased.

  The nodes in the network all serve as intermediate nodes in different transmission processes. Therefore, by sensing the channel, the RREP packet in its own MAC layer data storage unit 14 or the RREP message attached to the RREQ packet can be deleted, and the path establishment in the prior art is realized. It is necessary to add the data type control unit 37 to the device configuration diagram.

  As shown in FIG. 3, the receiving unit 16 is connected to the MAC layer data processing unit 13 through the data type control unit 37, and the data type control unit 37 is also connected to the MAC layer storage unit 14. The network layer data processing unit 32 shown in FIG. 3 provides counters and / or timers for different source nodes corresponding to the received RREQ packet, and when the RREQ packet is received, it corresponds to the received RREQ packet. RREP packets or RREP messages with RREP messages attached are not sent back immediately, but after waiting for a certain period of time or a certain number of RREQ packets, multiple RREP packets or RREP messages encapsulating multiple routing information are attached. RREQ packet is returned to the source node.

  The receiving unit 16 senses the channel and transmits the sensed packet to the MAC layer data processing unit 13 for processing. The data type control unit 37 checks the packet transmitted from the receiving unit 16 to the MAC layer data processing unit 13, acquires the RREP packet or the RREQ packet to which the RREP message is attached, and all of the MAC layer data storage unit 14 If there is the same RREP packet or RREQ packet as the currently acquired packet, the RREP message attached to the same RREP packet or RREQ packet in the MAC layer data storage unit 14 is deleted.

  Here, the same RREP packet or RREQ packet refers to two RREP packets or two RREQ packets having the same source node, destination node and transmission time message. Among them, the transmission time message is the transmission time written in the RREP packet returned by the destination node or the RREQ packet to which the RREP message is attached. The transmission time message represents the time when the RREP packet or the RREQ packet to which the RREP message is attached departs from the destination node.

  FIG. 4 shows that the intermediate node deletes the same RREP packet as sensed in its MAC layer data storage unit 14 or the RREP message attached to the same RREQ packet through channel sensing in step 211. It can be realized by such a process. The specific process is as follows.

  In steps 401 to 402, in the channel sensing process of the intermediate node, the receiving unit 16 transmits the sensed packet to the MAC layer data processing unit 13 for processing. The data type control unit 37 checks the packet transmitted from the receiving unit 16 to the MAC layer data processing unit 13, checks the packet type domain and extension domain, obtains the packet type message, and RREP to the packet extension domain. It is determined whether or not a message is attached, and further, it is determined whether or not the packet to be transmitted to the MAC layer data processing unit 13 is an RREP packet or an RREQ packet attached with an RREP message. If so, get the RREQ packet or RREP packet and go to step 403, otherwise go back to step 401 and continue to check the packet sent from the receiving unit 16 to the MAC layer data processing unit 13 To do.

  In step 403, the source address, destination address, and transmission time attached to the currently acquired RREP packet or RREQ packet are acquired, and then all packets in the MAC layer data storage unit 14 are searched, and the current sensing is performed. It is determined whether or not the same packet as the RREP packet or the RREQ packet to which the RREP message is attached is present. If there is, the process proceeds to step 404. If not, the process returns to step 401.

  The method of searching all packets in the MAC layer data storage unit 14 searches all packets in the MAC layer data storage unit 14 for each acquired RREP packet or RREQ packet with an RREP message. This is to search for the same packet as the acquired RREP packet or RREQ packet. Here, the same packet refers to a packet having the same source node, the same destination node, and the same transmission time.

  In step 404, if it is RREP, the data type control unit 37 deletes the same packet as the RREP packet currently sensed in the MAC layer data storage unit 14, and if it is an RREQ packet, the data type control unit 37 reads the MAC layer data. In the storage unit 14, the RREP message attached to the same RREQ packet as the currently acquired RREQ packet is deleted. Next, returning to step 401, the packet transmitted from the receiving unit 16 to the MAC layer data processing unit 13 is subsequently checked.

  Further, in the present invention, the RREP message attached to the same RREP packet as the sensed RREP packet or the same RREQ packet as the currently acquired RREQ packet in the own MAC layer data storage unit 14 is deleted through channel sensing. This can be realized by a method as shown in FIG.

  At this time, the data type control unit 37 needs to create a message table in the data type control unit 37 for the packet to be transmitted in the MAC layer data storage unit 14. Determine the data type for each packet entering the MAC layer data storage unit 14, determine whether the data type is an RREP packet or an RREQ packet, and if it is an RREP packet, the source node and destination node of the RREP packet Record the sending time message. If it is determined that the data type is an RREQ packet, it is determined whether or not an RREP message is attached to the RREQ packet. If an RREP message is attached, the source node, the destination node, and the transmission time of the RREQ packet are transmitted. Message is recorded, and if the RREP message is not attached to the RREQ packet, it is not recorded. At the same time, for each RREQ packet or each RREP packet with an RREP message transmitted from the MAC layer data storage unit 14, the item in the message table of the message is deleted. The data type control unit 37 checks the packet transmitted from the receiving unit 16 to the MAC layer data processing unit 13, determines the data type of the packet, and the same packet as the RREP packet arranged in the message table in the MAC layer data storage unit 14 Alternatively, the RREP message attached to the same RREQ packet as the currently acquired RREQ packet is deleted. Here, the same RREP packet or RREQ packet refers to two RREP packets or two RREQ packets having the same source node, the same destination node, and the same transmission time message.

  Among them, the transmission time message is the transmission time written in the RREP packet returned by the destination node or the RREQ packet to which the RREP message is attached. The transmission time message represents a time point when the RREP packet or the RREQ packet to which the RREP message is attached starts from the destination node.

  In step 211, the intermediate node uses the process as shown in FIG. 5 to perform the same channel sensing as the RREP packet that is the same as the sensed RREP packet in the MAC layer data storage unit 14 or the same as the currently acquired RREQ packet. The RREP message attached to the RREQ packet can be deleted. The process shown in FIG. 4 is different from the process shown in FIG. 5 in that the data type control unit 37 acquires the RREQ packet, not the RREQ packet with the RREP message. Correspondingly, in FIG. 5, the determination will determine whether the RREQ packet is stored in the MAC layer data storage unit 14, and determine whether the RREQ packet with the RREP message is stored. Not that. The specific process is as follows.

  In steps 501 to 502, in the channel sensing process of the intermediate node, the receiving unit 16 transmits the sensed packet to the MAC layer data processing unit 13 for processing. The data type control unit 37 checks the packets transmitted from the receiving unit 16 to the MAC layer data processing unit 13 and determines whether each packet is an RREQ packet or an RREP packet. RREQ packet or RREP packet is acquired, and the process proceeds to step 503. Otherwise, the process returns to step 501, and the packet transmitted from the receiving unit 16 to the MAC layer data processing unit 13 is subsequently checked.

  In step 503, the source address, destination address, and transmission time message attached to the currently acquired RREP packet or RREQ packet are acquired, and then the RREP packet or RREQ arranged in the message table in the data type unit 37 is acquired. It is determined whether the packet is the same as the currently sensed RREP packet or RREQ packet. If so, the process proceeds to step 504; otherwise, the process returns to step 501.

  In step 504, the data type control unit 37 deletes the RREP packet in the MAC layer data storage unit 14, or deletes the RREP message attached to the RREQ packet, and then returns to step 501 to return from the receiving unit 16. The packet sent to the MAC layer data processing unit 13 is subsequently checked.

  In the present invention, the intermediate node transmits the RREP message attached to the same packet as the sensed RREP or the same RREQ packet as the currently acquired RREQ packet in its MAC layer data storage unit 14 through channel sensing. Can be removed, thereby increasing the speed of route establishment, in addition to adjusting the column position in the MAC layer data storage unit 14 of the routing packet, relatively high in the routing packet By giving priority, the route control packet can access the channel at a higher speed than other packets, thereby increasing the speed of route establishment.

  In order to realize the adjustment of the position of the column in the MAC layer data storage unit 14 of the route control packet, it is necessary to add the priority control unit 68 to the configuration diagram of the device for realizing the route establishment in the prior art. As shown in FIG. 6, the priority control unit 68 is connected to the MAC layer data storage unit 14, performs priority control of the route control packet entering the MAC layer data storage unit 14 from the MAC layer data processing unit 13, Adjust the position of the column in the MAC layer data storage unit 14 of the routing packet, give the routing packet a higher priority, thereby reducing the waiting time in the MAC layer data storage unit 14 of the routing packet, Route control packets are accessed at higher speeds to increase the speed of route establishment. Among them, the route control packet is a control message related to routing, for example, an RREQ packet, an RREP packet, a route error packet (RRER), or a route confirmation packet.

  In the process as shown in FIG. 7, the principle of creating a column adopted by the MAC layer data storage unit 14 is first-in first-out. Even when adopting other principles for creating a queue, for example, last-in-first-out, routing packets are sent sequentially prior to other packets by adjusting the position of the routing packet in the queue. be able to. The specific process is as shown in FIG.

  In steps 701 to 702, the priority control unit 68 determines each packet transmitted from the MAC layer data processing unit 13 to the MAC layer data storage unit 14, and determines whether or not the received packet is a routing packet. . If it is a route control packet, the process proceeds to step 704; otherwise, the process proceeds to step 703.

  In step 703, a packet that is not a route control packet is placed at the end of the packet queue for transmission in the MAC layer data storage unit 14.

  In step 704, for the routing packet, the priority control unit 68 searches from the tail to the front of the packet queue for transmission in the MAC layer data storage unit 14 and searches for the routing packet. If yes, go to Step 705, otherwise go to Step 706.

  If a routing control packet waiting for transmission is found in the MAC layer data storage unit 14 in step 705, the routing control packet currently received is inserted after the first routing control packet found.

  In step 706, if there is no routing control packet waiting to be transmitted in the MAC layer data storage unit 14, the currently received routing control packet is inserted in front of the column of the MAC layer data storage unit 14. Thus, the currently received route control packet is first accessed in the channel at the next time point.

  As shown in FIG. 8, it is preferable to add the priority control unit 68 and the data type control unit 37 simultaneously to the configuration diagram of the apparatus for realizing the path establishment in the prior art.

  In FIG. 8, the priority control unit 68 is connected to the MAC layer control unit 14, adjusts the column position in the MAC layer data storage unit 14 of the route control packet, gives the route control packet higher priority, The waiting time of the control packet in the MAC layer data storage unit 14 is reduced, and the speed of path establishment is increased. The data type control unit 37 is connected to the receiving unit 16, the MAC layer data processing unit 13, and the MAC layer data storage unit 14, respectively, and through checking packets transmitted from the receiving unit 16 to the MAC layer data processing unit 13, It is realized to delete the RREP packet attached to the same RREP packet as the sensed RREP packet or the same RREQ packet as the currently sensed RREQ packet. The specific implementation steps are the same as the processes shown in FIG. 4 and FIG. 6, or FIG. 5 and FIG.

  The above are only preferred embodiments of the present invention and do not limit the protection scope of the present invention. Various modifications, equivalent switching, improvements and the like made within the spirit and principle of the present invention should all be included in the protection scope of the present invention.

It is a block diagram of the apparatus which implement | achieves path | route establishment. It is a flowchart of the method of implement | achieving high-speed path | route establishment in this invention. It is one apparatus block diagram which implement | achieves the high-speed path | route establishment in this invention. It is a process flowchart which senses adjacent node data in this invention. It is another process flowchart which senses adjacent node data in this invention. It is a block diagram of another apparatus which implement | achieves the high-speed path | route establishment in this invention. It is a flowchart which controls the priority of the route control packet in this invention. It is a block diagram of another apparatus which implement | achieves the high-speed path | route establishment in this invention.

Explanation of symbols

11 ... path buffer unit, 12 ... network layer data processing unit, 13 ... MAC layer data processing unit, 14 ... MAC layer data storage unit, 15 ... transmitting unit, 16 ... receiving unit, 32 ... network layer data processing unit, 37 ... Data type control unit, 68 ... Priority control unit

Claims (19)

A fast route establishment method,
The destination node receives the route request packet and encapsulates the route information attached to the route request packet received from each route into one route response packet corresponding to the source node of the route request packet. ,
Determine whether the route response packet can be transmitted, and if so, send the packet with the route response message to the source node via the intermediate node; otherwise, return to step A, step B;
A method comprising the steps of: The packet to which the route response message is attached in step B is a route response packet or a route request packet to which a route response message is attached.
The method according to claim 1, wherein: The determination in step B is to execute step A and determine in real time.
3. The method according to claim 1 or 2, wherein Further comprising providing a timer and setting a timekeeping time;
In step A, the destination node further includes starting a timer after receiving the first route request packet of the source node;
Determining whether the transmission is possible in step B is determining whether the timer has timed up and transmitting when the time is up, otherwise not transmitting.
3. The method according to claim 1 or 2, wherein The determination in step B is to execute step A and determine in real time.
The method according to claim 4, wherein: Each node that participates in route establishment sends a packet before
Determine whether the received packet is a route control packet, if so, store the packet in the transmission buffer, and preferentially send all the route control packets waiting for transmission, otherwise Further comprising storing the packet in a transmit buffer and transmitting normally;
6. The method according to claim 5, wherein: Further comprising providing a counter and setting a count value, wherein in step A, the destination node further includes starting the counter after receiving the first route request packet of the source node;
Determining whether the transmission in step B is possible is to determine whether the counter has reached the set count value, and if so, it can be transmitted, otherwise it cannot be transmitted.
3. The method according to claim 1 or 2, wherein Each node that participates in route establishment sends a packet before
Determine whether the received packet is a route control packet, if so, store the packet in the transmission buffer, and preferentially send all the route control packets waiting for transmission, otherwise Store the packet in the send buffer and send it successfully,
The method of claim 7, further comprising: Providing a timer and a counter, and further setting a time count and a count value, and in step A, after receiving the first route request packet of the source node, the destination node starts the timer and the counter simultaneously. In addition,
Determining whether the transmission is possible in step B determines whether the timer has timed out or if the counter has reached a count, if so, it can be transmitted, otherwise it is transmitted. Is not possible,
3. The method according to claim 1 or 2, wherein Determining whether the timer in step B has timed up is performing step A and determining in real time whether the timer has timed up,
10. The method of claim 9, wherein The packet with the route response message transmitted from the intermediate node to the source node is a route request packet with the route response message attached, and the route request packet with the route response message attached from the intermediate node to the source node. Specifically, sending to
The intermediate node senses the broadcast channel and obtains a route request packet transmitted from the adjacent node;
The intermediate node searches for the packet waiting for its current transmission, and deletes the route response message attached to the same route request packet as the packet acquired in step B11; and
The method of claim 1, comprising: The acquired route request packet transmitted from the adjacent node in step B11 is a route request packet to which a route response message is attached.
12. The method of claim 11, wherein: The packet with a route response message transmitted from the intermediate node to the source node is a route response packet, and specifically, transmitting the route response packet from the intermediate node to the source node
The intermediate node senses the broadcast channel and obtains a route response packet transmitted from the adjacent node.
B22, the intermediate node searches for the packet waiting for its current transmission, and deletes the same route response packet as the packet acquired in step B21.
The method of claim 1, comprising: Before each node participating in route establishment sends a packet,
Determine whether the received packet is a route control packet, if so, store the packet in the transmission buffer, and preferentially send all the route control packets waiting for transmission, otherwise Store the packet in the send buffer and send it successfully,
14. The method of claim 1, claim 2, claim 11, claim 12, or claim 13, further comprising: A path buffer unit, a network layer data processing unit, a media access control (MAC) layer data processing unit, a media access control layer data storage unit, a transmission unit and a reception unit;
The network layer data processing unit receives an upper layer data message, sends the processed data and the generated routing control packet to the media access control layer data processing unit for processing,
The path buffer unit provides a search for path information for a network layer data processing unit;
The media access control layer data processing unit stores the processed packet in the media access control layer data storage unit and waits for transmission,
When the media access control layer data storage unit detects that a broadcast channel is available, it transmits through the transmission unit;
The receiving unit transmits a message sensed from a broadcast channel to a media access control layer data processing unit for processing.
A high-speed route establishment device,
The network layer data processing unit further comprises a transmission trigger, the network layer data processing unit receives a packet from a media access control layer data processing unit and is attached to one or more route request packets. The route information is encapsulated in one route response packet, and when the first route request packet from the source node is received, the transmission trigger is started, and the trigger of the transmission trigger (triggering) Send the attached packet to the media access control layer data processing unit,
The transmission trigger is for triggering the network layer data processing unit to transmit a packet with a route response message.
A device characterized by that. The transmission trigger is a timer or a counter.
16. The apparatus according to claim 15, wherein The packet to which the route response message is attached is a route response packet or a route request packet to which the route response message is attached.
Check the packet sent from the receiving unit to the media access control layer data processing unit, get the route response packet, delete the same route response packet as the obtained route response packet, and / or have a route response message attached A data type control unit that acquires the route request packet and deletes a route response message attached to the same route request packet as the acquired route request packet;
17. An apparatus according to claim 15 or claim 16, wherein A priority control unit that controls the routing messages to be sequentially sent in priority in the media access control layer data storage unit;
17. The apparatus according to claim 15 or 16, further comprising: The packet to which the route response message is attached is a route response packet or a route request packet to which the route response message is attached.
Check the packet sent from the receiving unit to the media access control layer data processing unit, obtain the route response packet, delete the same route response packet as the obtained route response packet, and / or have a route response message attached A data type control unit that acquires a route request packet and deletes a route response message attached to the same route request packet as the acquired route request packet;
A priority control unit for controlling the routing messages to be sequentially transmitted in priority in the media access control layer data storage unit;
17. The apparatus according to claim 15 or 16, further comprising:

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