JP2007325261A - Method of establishing route - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of route establishment which raises the efficiency of the route establishment, in a wireless communication network in which node has routing function. <P>SOLUTION: When a route to an address node exists in a source node and the route is determined so as to be an effective route based on the energy and amount of traffic of an intermediate node in the route, a data packet is transmitted through the route. When it is not, a step A which broadcasts RREQ to which traffic amount is attached, a step B, in which a node which received the RREQ judges whether himself is addressed node or not and when it is the addressed node, it carries out a step D but when it is not the addressed node, it carried out a step C, the step C which detects an effective route until the addressed node from the node when the intermediate node is determined so as to be the effective node, and a step D which replies a route from the source node to the addressed node and the RREP to which the energy of respective node on the route from the source node to the addressed node and the route to the source node is attached while the source node transmits the data packet in accordance with the route in the RREP, are comprised. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a routing technique, and more particularly to a route establishment method in a wireless network in which a node has a routing function.

  In recent years, wireless networks have been rapidly developed because people have been demanding free communication regardless of time and place by breaking away from the constraints of wired networks. Ad hoc network technology has emerged in time to enable wireless communication in areas without fixed wired infrastructure. In this network, a multi-hop, temporary autonomous network without a base station is configured by a set of mobile nodes equipped with wireless handsets. In addition, each mobile node has a router function, and can perform data packet transmission / reception and transfer functions in the data communication process.

  Ad hoc networks do not require support for a fixed wired infrastructure, so the ad hoc network's self-organizing features allow for cheaper and faster network deployment and multi-hop compared to traditional communication networks. The transmission range of each terminal can be reduced without reducing the network coverage by the route and the transfer characteristic of the intermediate node. This reduces the difficulty in designing the antenna and the related transmission / reception elements and the power consumption of the equipment, and enables downsizing and low power consumption of the mobile terminal. Also, depending on the stability and resistance to destruction of the Ad hoc network, it is possible to meet specific application needs such as military communications, disaster relief and temporary communications.

  Fig. 1 is a block diagram of the Ad hoc network. Usually, mobile nodes in the Ad hoc network are abbreviated as nodes. Referring to FIG. 1, for example, an ad hoc network includes nodes A, B, and C, in which node B is simultaneously within the coverage of nodes A and C, each of nodes A and C Is outside the coverage of the partner node. In the ad hoc network, other nodes located within the coverage of one node become adjacent nodes of the node, and each of the nodes can directly communicate with its own adjacent node. However, because the transmission power and coverage of each node is finite, if a node needs to communicate with a node outside its coverage, it needs to be forwarded to another node in the network, where it joins the forwarding A node is called an intermediate node. Taking communication between node A and node C as an example, node B as an intermediate node provides a path between two nodes A and C and plays a role of transfer. In this way, communication between nodes is realized through a multi-hop route scheme.

  From the above, it can be seen that the establishment of the route is an important factor that guarantees the normal operation of the Ad hoc network. Currently, the most commonly used Ad hoc network routing protocols are Dynamic Source Routing (DSR) and Ad hoc On Demand Distance Vector (AODV) established by the Mobile Ad Hoc Network (MANET) Working Group of the International Internet Engineering Task Force (IETF). ) Routing protocol.

  FIG. 2 is a flowchart of a route establishment method based on the conventional DSR protocol. Referring to FIG. 2, the method includes the following steps.

  In step 201, the source node receives a data packet from an upper layer of the network.

  In steps 202 to 204, it is determined whether or not the route to the destination node is stored in the source node. If the route is stored, the data packet is transmitted according to the stored route, and this route establishment process is performed. If the source node is not saved, the source node searches for a route to the destination node by broadcasting a route request packet (RREQ) with the address of the source node and the address of the destination node, followed by Step 205 is executed.

  In steps 205 to 206, the RREQ broadcast by another node is received by the intermediate node, the route information record in the intermediate node is updated based on the received RREQ, and the intermediate node corresponds to the RREQ. If it is a destination node corresponding to RREQ, step 209 is executed, and if not, step 207 is executed.

  Each of the nodes of the Ad hoc network has a path information record for storing path information when the node is a source node and another node is a destination node. Since the RREQ includes not only the addresses of the source node and the destination node but also the route information of the intermediate node through which the RREQ has passed, the intermediate node in this step analyzed the route information from the received RREQ and analyzed it. Update your route information record with the route information.

  In Steps 207 to 208, it is determined whether or not a route to the destination node exists in the intermediate node, and if it exists, Step 209 is executed. If not, the intermediate node adds its own route information to the RREQ, broadcasts the RREQ that has been added, and returns to step 205.

  In Steps 209 to 210, a route response packet (RREP) is returned to the source node, and the source node updates its route information record based on the received RREP and returns to Step 202.

  In the RREP returned from the intermediate node to the source node, path information from the source node to the intermediate node and path information from the intermediate node to the destination node are attached. Route information from the source node to the destination node is attached to the RREP returned from the destination node to the source node. The source node acquires route information from the source node to another node by updating its route information record based on the route information attached to the RREP.

  Thus far, the conventional path establishment process is completed.

  As can be seen from the above steps, in the conventional route establishment method, the intermediate node continuously broadcasts after receiving RREQ. In actual applications, nodes are powered by batteries, so their energy is finite. Thus, in the process of data transmission after the establishment of the path, there is a case where data cannot be transferred because the energy of the intermediate node is insufficient. In this case, the path establishment process can only be restarted to search for another path. Therefore, it can be seen that the efficiency of the conventional route establishment method is relatively low.

The present invention has been made in view of the above, and provides a route establishment method for improving the efficiency of route establishment in a wireless network in which a node has a routing function.

The method based on the inventive concept of the present invention comprises:
It is determined whether the route to the destination node corresponding to the data packet transmitted this time exists in the source node, the route to the destination node exists in the source node, and the energy of the intermediate node in the route and the If the route is determined to be a valid route based on the traffic volume corresponding to the data packet, the data packet is transmitted through the route; otherwise, the source node requests the route request to which the traffic amount is attached. Step A for broadcasting the packet RREQ;
The node that has received the RREQ determines whether or not it is the destination node, and if it is the destination node, directly executes step D, and if it is not the destination node, executes step C;
If the intermediate node is determined to be a valid node based on the energy of the node and the amount of traffic corresponding to the data packet, step C for searching for a valid route from the node to the destination node;
A route D from the source node to the destination node and a route response packet RREP to which energy of each node on the route is attached is returned to the source node, and the source node transmits a data packet according to the route in the RREP; ,including.

Here, in step A, it is determined whether or not a route to the destination node exists in the source node.
The source node uses the destination node in the data packet as an index, searches for the item corresponding to the destination node in its route information record, and if found, determines that the route to the destination node exists in the source node; If not found, it is determined that the route to the destination node does not exist in the source node.

Here, when the energy of the intermediate node is included in the route information record, in step A, the route is determined as an effective route,
This includes determining that the route is an effective route when it is determined that all the energy of each intermediate node in the route to the destination node can satisfy the current data packet transmission.

  Here, in the step A, when it is determined that there is an intermediate node whose energy cannot satisfy the current data packet transmission in the route to the destination node, the source node is assigned a traffic amount in the step A. The method further includes performing an operation of broadcasting the RREQ.

Here, in step C, the intermediate node is determined as a valid node.
When it is determined that the energy of the intermediate node can satisfy the transmission of the data packet this time, the intermediate node is determined to be a valid node.

  Here, in the step C, when it is determined that the energy of the intermediate node cannot satisfy the transmission of the current data packet, the RREQ is discarded and the process returns to the step B.

Here, when the energy of the intermediate node is included in the route information record, searching for an effective route to the destination node in Step C is:
When a route to the destination node is searched for in the route information record of the intermediate node, and all the energy of each intermediate node in the route can satisfy the transmission of the current data packet, the route is determined to be an effective route. is there.

  Here, in the step C, when the route to the destination node is not found in the route information record of the intermediate node, broadcast the RREQ with the address and energy of the intermediate node, and return to the step B Is further included.

  Here, in step C, when it is determined that there is an intermediate node whose energy cannot satisfy the current data packet transmission in the path to the destination node, the address and energy of the intermediate node that received the RREQ are attached. Further broadcasting the current RREQ and returning to step B above.

Here, set the lower limit of energy in advance,
It is determined that the energy of the intermediate node can satisfy the transmission of the data packet this time.
Based on the traffic volume corresponding to the data packet, calculate the energy required to transmit the data packet,
Obtaining the residual energy of the intermediate node by calculating the difference between the energy of the intermediate node and the energy required for transmission of the data packet;
It is determined whether or not the residual energy of the intermediate node is equal to or higher than the lower limit of the energy, and if it is equal to or higher than the lower limit, it is determined that the energy of the intermediate node can satisfy the transmission of the current data packet.

Here, set the consumption rate of the highest energy in advance,
It is determined that the energy of the intermediate node can satisfy the transmission of the data packet this time.
Based on the traffic volume corresponding to the data packet, calculate the energy required to transmit the data packet,
Calculating the ratio of the energy required for transmission of the data packet to the energy of the intermediate node;
It is determined whether each of the calculated ratio values is smaller than the consumption rate of the maximum energy, and if it is small, it is determined that the energy of the intermediate node can satisfy the transmission of the current data packet.

Here, a minimum energy remaining rate is set in advance,
It is determined that the energy of the intermediate node can satisfy the transmission of the data packet this time.
Based on the traffic volume corresponding to the data packet, calculate the energy required to transmit the data packet,
By calculating the difference between the energy of the intermediate node and the energy required for transmission of the data packet, the surplus energy of the intermediate node is obtained, the ratio of the residual energy and the initial energy of the corresponding intermediate node is calculated,
It is determined whether each of the calculated ratio values is equal to or higher than the remaining rate of the minimum energy, and if it is equal to or higher than the remaining rate, it is determined that the energy of the intermediate node can satisfy the transmission of the current data packet. Including that.

  Broadcasting the RREQ is broadcasting the RREQ according to all probabilities.

Here, the energy level and the broadcast probability corresponding to each energy level are set in advance,
Broadcasting the RREQ
Determine an energy level corresponding to the difference between the energy of the intermediate node that broadcasts the RREQ and the energy required for transmission of the data packet, or the energy level required for transmission of the data packet and the energy of the intermediate node Determining an energy level corresponding to the ratio, or determining an energy level corresponding to a ratio between the energy of the intermediate node and the energy required for transmission of the data packet and the initial energy of the intermediate node;
RREQ is broadcast according to the broadcast probability corresponding to the energy level.

  Here, before step A, the source node further includes receiving a data packet to be transmitted this time and determining a traffic amount and a destination node corresponding to the data packet.

  Here, prior to the determination in step B, the method further includes the intermediate node receiving the RREQ updating its route information record based on the RREQ.

  Here, before the source node transmits a data packet according to the path in the RREP in step D, the method further includes the source node updating its path information record based on the RREP.

  Here, before executing Step C in Step B, the method determines whether or not the intermediate node that has received the RREQ has received the RREQ for the first time. It further includes discarding RREQ and returning to the determination in step B, otherwise performing step C subsequently.

  ADVANTAGE OF THE INVENTION According to this invention, the efficiency of path | route establishment can be improved in the wireless network in which a node has a routing function. Specifically, the present invention has the following beneficial effects.

  In the present invention, the amount of traffic that needs to be transmitted is attached to the route request packet transmitted from the source node, and the energy of each intermediate node in the route from the source node to the destination node is all of the current data packet. Only when the transmission is sufficient, the route is determined as a valid route, and the data packet is transmitted to the destination node using the valid route. In the path establishment process, the present invention effectively avoids the reconstruction of the path due to the energy shortage of the intermediate node in the data transmission process, and can quickly find a node and a path with sufficient energy, thereby improving the efficiency of the path establishment. Yes.

  In the present invention, the probability of RREQ broadcast can be determined based on the energy of the intermediate node. In this scheme, the higher the energy level of the intermediate node, the higher the probability of RREQ broadcast. Conversely, the lower the energy level of the intermediate node, the lower the probability of RREQ broadcast. In this way, it is advantageous for improving the fairness of energy consumption of nodes, and is effective in reducing the energy over-consumption situation of some nodes.

  In order to further clarify the objects and technical solutions of the present invention, the present invention will be described in more detail with reference to the drawings.

  The present invention is a route establishment method in a wireless network in which a node has a routing function. As its core invention concept, node devices participate in path establishment only when their energy sufficiently meets the traffic needs.

  FIG. 3 is a flowchart showing an example of a route establishment method in the present invention. Referring to FIG. 3, the method includes the following steps.

  In step 301, it is determined whether a route to the destination node corresponding to the data packet to be transmitted this time exists in the source node, a route to the destination node exists in the source node, and an intermediate node of the route When the route is determined to be an effective route based on the energy and the traffic amount corresponding to the data packet, the data packet is transmitted through the route. Otherwise, the source node broadcasts a route request packet RREQ with a traffic volume.

  In step 302, the node that has received the RREQ determines whether or not it is the destination node, and if it is the destination node, executes step 304; otherwise, executes step 303.

  In step 303, when the node is determined to be a valid node based on the energy of the node and the traffic amount corresponding to the data packet, the node searches for a valid route to the destination node.

  In step 304, a route response packet RREP is returned to the source node, and the route from the source node to the destination node and energy information of each node on the route are attached to the RREP. A data packet is transmitted along the route.

  Hereinafter, the route establishment method of the present invention will be described using an example based on the DSR protocol.

In this embodiment, both the source node and the destination node have sufficient energy, and the route information record of each node not only stores the address information of each route from the node to another node. , To admit that energy information of nodes on each path is also stored. A format as shown in Table 1 can be adopted for the route information recording in the node in this embodiment.

In the above table, when explaining the contents of the first row as an example, the location node of the table reaches the destination node A through the intermediate nodes N1, N2 and N3, and the energy corresponding to the three intermediate nodes is are each E1, E2 and E3, and the energy corresponding to the destination node a is E _a.

  FIG. 4 is a flowchart of the route establishment method according to this embodiment. As shown in FIG. 4, the route establishment method of the present embodiment includes the following steps.

  In steps 401 to 402, the source node receives the data packet from the application layer, and determines the traffic amount and the destination node corresponding to the data packet.

  Here, after receiving the data packet, the source node first reads the information attached to the data packet, for example, the size of the data packet, the destination address, and then the size of the read data packet. The destination node is determined based on the destination address based on the corresponding traffic volume.

  In step 403, it is determined whether or not a route to the destination node exists in the source node. If it exists, step 404 is executed. If not, step 405 is executed.

  In this step, the source node uses the destination node in the data packet as an index and searches for an item corresponding to the destination node in its route information record. If found, it is determined that the route to the destination node exists in the source node. If not found, the route to the destination node is determined not to exist in the source node.

  In step 404, it is determined whether all the energy of each intermediate node in the path to the destination node can satisfy the request for data packet transmission this time, and if satisfied, execute step 408, and if not, continue Step 405 is executed.

  In the ad hoc network, the energy required for a node to transmit and receive data packets in a broadcast manner is as follows.

  For transmission, 1.9 x data packet size +266.

  For reception, 0.5 x data packet size + 56.

  Each energy calculated by the above equation is in units of microwatts · second / byte (μW · sec / byte).

  Since the intermediate node needs to transmit and receive data packets based on the above equation, the energy required for the intermediate node to transmit the data packet is (1.9 × data packet size + 266) + (0.5 × data packet size) +56) = 2.4 × data packet size + 322.

In this embodiment, when the lower limit of energy is set in advance and the difference between the energy in the node and the energy required for data packet transmission is lower than the lower limit of energy, it is determined that the energy of the node is insufficient. Here, after obtaining the energy required for data packet transmission, as a method of determining whether or not all the energy of each node can satisfy the current data packet transmission on the route to the destination node, first, the route information record And then calculating the difference between the acquired energy and the energy required to transmit the data packet to obtain the residual energy of each intermediate node and each remaining energy obtained Are all equal to or higher than the lower limit of energy, and if all the remaining energy obtained is equal to or higher than the lower limit of energy, it is determined that all the energy of all nodes can satisfy the transmission of the data packet this time, and so on. Otherwise, it is determined that there is a node whose energy cannot satisfy the data packet transmission this time. . If the lower limit of energy is E _min , the energy of the node is E, and the energy required for data packet transmission is _Et , the residual energy _{Er of the} node is E _r = E−E _t is there.

In this case, the energy of the node can satisfy the current data packet transmission, and if not, the current data packet transmission cannot be satisfied.

  Moreover, the consumption rate of the highest energy may be set in advance. In this case, whether or not the energy of the node can satisfy the transmission of the data packet this time is determined by the relationship between the ratio of the energy required for the transmission of the data packet and the energy of the intermediate node and the consumption rate of the highest energy decide. Specifically, when all the calculated ratios are smaller than the consumption rate of the highest energy, it is determined that the energy of the intermediate node can satisfy the transmission of the current data packet.

In this embodiment, the lowest energy remaining rate can be set in advance, and in this case, it is determined whether the energy of each node can satisfy the transmission of the current data packet all along the route to the destination node. Alternatively, after obtaining the source node's own energy, read the current energy of the intermediate node from the path information record, and then calculate the difference between the current energy of each node and the energy required to transmit the data packet Determining the ratio between the calculated difference value and the initial energy of the corresponding node, and then determining whether the determined ratio value is equal to or greater than the residual rate of the lowest energy and is equal to or greater than the residual rate. In this case, it is determined that all the energy of each node can satisfy the transmission of the current data packet. Determining a node that can not satisfy the transmission are present. If the residual rate of the lowest energy is r, the initial energy of the node is E ₀ , the current energy of the node is E _c , and the energy required for data packet transmission is E _t , The residual energy E _r is E _r = E _c −E _t .

In this case, the energy of the node can satisfy the current data packet transmission, and if not, the current data packet transmission cannot be satisfied.

  In step 405, the source node broadcasts an energized RREQ corresponding to the data packet.

  If the energy of each intermediate node in the path stored in the source node does not all satisfy the transmission of the data packet this time, the source node encapsulates the traffic volume corresponding to the data packet in RREQ, and the RREQ Will continue to broadcast.

  In step 406, the node that has received the RREQ determines an effective route based on the amount of traffic corresponding to the energy and the data packet, and returns valid route information to the source node.

  In step 407, the source node updates its route information record based on the received RREP.

  In step 408, the data packet is transmitted through the route in the RREP, and the current route establishment process is terminated.

  Up to this point, the path establishment process according to the present embodiment is completed.

  A specific method in which the node that has received the RREQ in step 406 determines a valid route and returns valid route information to the source node is as shown in FIG. As shown in FIG. 5, the method includes the following steps.

  In steps 501 to 502, the node that has received the RREQ updates its route information record based on the RREQ, determines whether or not this node is the destination node, and executes step 510 if it is the destination node. If it is not the destination node, step 502 is subsequently executed.

  The RREQ may have already been transferred by a plurality of intermediate nodes, and each intermediate node adds its own address and energy information to the RREQ in the process of transferring the RREQ. That is, since the route and energy information of the passed node are attached to the RREQ, the node receiving the RREQ analyzes the received RREQ and updates its own route information record based on the analysis result. Then, the route from the intermediate node to another node and the energy information of the corresponding node are added.

  In step 503, it is determined whether or not the RREQ has been received by the node for the first time, and if it is received for the first time, step 504 is executed, otherwise, an operation of discarding the RREQ in step 506 is executed, and Return to step 501.

  For RREQ, the source node, the destination node, and the broadcast sequence number of the RREQ jointly constitute the core part of the RREQ, and RREQs having the same three core parts are duplicate RREQs. In order to prevent a node from performing the same processing operation a plurality of times for the duplicate RREQ, in this embodiment, the subsequent operation is executed only when the same RREQ is not received.

  In steps 504 to 506, the node that has received RREQ acquires its own residual energy, determines whether the acquired residual energy can satisfy the transmission of the data packet this time, and if so, executes step 507. If not satisfied, the received RREQ is discarded and the process returns to step 501.

  A node that has received RREQ and is not a destination node is an intermediate node. Here, the energy required for the transmission of the data packet is determined according to the same method as in step 404, and the energy corresponding to the transmission of the data packet is subtracted from the current energy of the node that has received the RREQ, to thereby determine the remaining energy of the prospect of the node Get. When the lower limit of energy is set in advance, it is determined here whether or not the node can satisfy the current data packet transmission by comparing the remaining energy of the node with the lower limit of the energy. If the maximum energy consumption rate is set in advance, here, the node compares the ratio of the energy required for data packet transmission with the energy of the intermediate node and the maximum energy consumption rate. It is determined whether the transmission of the data packet can be satisfied. When the minimum energy remaining rate is set in advance, the node satisfies the current data packet transmission by comparing the ratio between the remaining energy and the initial energy of the node with the minimum energy remaining rate. Determine if you can.

  If the node that has received the RREQ cannot execute the data packet transmission this time, the node is not a valid intermediate node. When the source node selects a location route of the node and transmits a data packet, the route cannot be used due to lack of energy in the data packet transmission process, so the route must be rebuilt and the data packet retransmitted. I must. Therefore, in this case, the RREQ may be discarded directly without performing any processing.

  In step 507, it is determined whether or not there is a route to the destination node in the node that has received the RREQ. If it exists, step 508 is subsequently executed. If not, step 509 is directly executed.

  In step 508, it is determined whether or not the energy of the intermediate node in the route can satisfy the transmission of the current data packet. If the energy is satisfied, step 510 is executed. If not, step 509 is executed.

  In this step, determination is performed using the same method as in step 404.

  Steps 504 to 508 are operations for determining an effective route.

  In step 509, the address of the node that received the RREQ and the RREQ attached with energy are broadcast, and the process returns to step 501.

  When the energy of the intermediate node that has received the RREQ is sufficient and there is no valid route to the destination node in the intermediate node, the intermediate node broadcasts the RREQ with its own address and energy information added.

FIG. 6 is a diagram illustrating an internal configuration of the RREQ according to the present embodiment. Referring to FIG. 6, RREQ includes source node address, destination node address, broadcast sequence number, source node energy E _{source node} , intermediate node address N ₁ ... N _m , and energy E ₁ ... E _m corresponding to the intermediate node. And the amount of traffic corresponding to the data packet.

  In step 510, the node that has received RREQ returns the route information from itself to the destination node and RREP to which energy corresponding to each node is attached to the source node.

  If the node that received the RREQ is the destination node or an intermediate node that has a valid route to the destination node, the RREP sent back to the source node contains the route information from the source node to the destination node, that is, the node's An address and corresponding energy information are attached.

  Thus far, the process of determining a valid route and returning valid route information is completed.

  As can be seen from the above description, in this embodiment, the route request packet transmitted from the source node is attached with the amount of traffic that needs to be transmitted, and each intermediate node in the route from the source node to the destination node. Only when the current energy is sufficient for the transmission of the current data packet, the route is determined as a valid route, and the data packet is transmitted to the destination node using the valid route. In the above technical scheme, nodes and paths having sufficient energy can be selected quickly, and the reconstruction of the path due to the shortage of energy in the intermediate node in the data transmission process is reduced, and the efficiency of path establishment is improved.

  In this embodiment, the intermediate node itself is a valid node, that is, a node whose energy can satisfy the transmission of the data packet, but if it cannot find a valid route to the destination node, it transmits RREQ by broadcast. That is, RREQ is broadcast according to the total probability. In order to avoid excessive broadcasting of RREQ, in step 509 of the present embodiment, RREQ may be broadcast using a broadcast probability determination method based on node energy. In this scheme, one or a plurality of energy level thresholds t1, t2... Ti are set in advance, and broadcast probabilities ρ1, ρ2... Ρi corresponding to each energy level are set, where t1> t2>. ρ1> ρ2>...> ρi. If the remaining energy of the intermediate node is t1 or more, the remaining energy becomes energy level 1, and then RREQ is broadcast using probability ρ1. If the remaining energy of the intermediate node is equal to or greater than t2 and smaller than t1, the remaining energy becomes energy level 2, and then RREQ is broadcast using probability ρ2. By analogy with this, the probability of RREQ broadcast is determined based on the relationship between the remaining energy of the intermediate node and the energy level threshold. Even when it is determined whether the node is valid based on the remaining rate of the lowest energy, a method of broadcasting the RREQ according to the different broadcast probabilities can be used.

  When the energy level of each node is relatively high at the initial stage of network operation, most of the energy at the intermediate node can satisfy the energy needs, but as the number of communications increases, the energy of the node decreases to some extent. The Therefore, the probability of RREQ broadcast can be determined based on the energy of the intermediate node. The higher the energy level of the intermediate node, the higher the probability of RREQ broadcast. Conversely, the lower the energy level of the intermediate node, the lower the probability of RREQ broadcast. Thus, it is advantageous for improving the fairness of energy consumption of the node, and effective in reducing the energy over-consumption situation of the node.

  In this embodiment, the following two methods can be used by updating the own route information record by the node. One is to add a new item to the path information record, and obtain the minimum value of the energy of the same node in steps 404 and 508 to obtain the current energy of the node. The other is to switch the original record of the node with the energy just received, thus directly reading the energy corresponding to the node in steps 404 and 508.

  The above is a route establishment method using the DSR protocol as an example. The above method can also be applied to an ad hoc network based on AODV protocol or the like. In short, the method of the present invention is applied to a wireless network in which a node has a routing function.

  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 an Ad hoc network. It is a flowchart of the route establishment method based on the conventional DSR protocol. It is a flowchart which shows the example of the route establishment method of this invention. 3 is a flowchart of a route establishment method according to an embodiment of the present invention. 6 is a flowchart of a method in which a node that has received an RREQ determines a valid route and returns valid route information to a source node according to an embodiment of the present invention. It is a block diagram of RREQ by the Example of this invention.

Explanation of symbols

A, B, C ... nodes, E _{source node} ... source node energy, N ₁ to N _m ... intermediate node addresses, energy corresponding to E ₁ to E _m ... intermediate node

Claims (18)

A route establishment method,
It is determined whether the route to the destination node corresponding to the data packet transmitted this time exists in the source node, the route to the destination node exists in the source node, and the energy of the intermediate node in the route and the If the route is determined to be a valid route based on the traffic volume corresponding to the data packet, the data packet is transmitted through the route; otherwise, the source node requests the route request to which the traffic amount is attached. Step A for broadcasting the packet RREQ;
The node that has received the RREQ determines whether or not it is the destination node, and if it is the destination node, directly executes step D, and if it is not the destination node, executes step C;
If the intermediate node is determined to be a valid node based on the energy of the node and the amount of traffic corresponding to the data packet, step C for searching for a valid route from the node to the destination node;
A route D from the source node to the destination node and a route response packet RREP to which energy of each node on the route is attached is returned to the source node, and the source node transmits a data packet according to the route in the RREP; A path establishment method comprising: Determining whether a route to the destination node exists in the source node in step A,
The source node uses the destination node in the data packet as an index, searches for the item corresponding to the destination node in its route information record, and if found, determines that the route to the destination node exists in the source node; 2. The route establishing method according to claim 1, wherein if the route is not found, it is determined that the route to the destination node does not exist in the source node. When the intermediate node energy is included in the route information record, in step A, the route is determined as an effective route,
The method according to claim 2, further comprising: determining that the route is an effective route when it is determined that all the energy of each intermediate node in the route to the destination node can satisfy the transmission of the data packet this time. The route establishment method described.   In step A, if it is determined that there is an intermediate node whose energy cannot satisfy the current data packet transmission in the path to the destination node, the RREQ to which the source node is attached a traffic amount in step A 4. The route establishment method according to claim 3, further comprising executing an operation of broadcasting the message. In step C, the intermediate node is determined to be a valid node.
2. The route establishment method according to claim 1, wherein when it is determined that the energy of the intermediate node can satisfy the transmission of the data packet this time, the intermediate node is determined to be a valid node.   6. The method of claim 5, further comprising discarding the RREQ and returning to the step B when it is determined in the step C that the energy of the intermediate node cannot satisfy the transmission of the data packet this time. Route establishment method. If the route information record includes energy of an intermediate node, searching for an effective route to the destination node in step C is as follows:
When a route to the destination node is searched for in the route information record of the intermediate node, and all the energy of each intermediate node in the route can satisfy the transmission of the current data packet, the route is determined to be an effective route. 3. The route establishment method according to claim 2, wherein the route establishment method is provided.   In the step C, if the route to the destination node is not found in the route information record of the intermediate node, the method further includes broadcasting the RREQ with the address and energy of the intermediate node and returning to the step B. 8. The route establishing method according to claim 7, wherein   In Step C, when it is determined that there is an intermediate node whose energy cannot satisfy the current data packet transmission in the route to the destination node, the address of the intermediate node that received the RREQ and the RREQ with the energy attached 8. The route establishment method according to claim 7, further comprising: broadcasting a message and returning to step B. Set the lower limit of energy in advance,
It is determined that the energy of the intermediate node can satisfy the transmission of the data packet this time.
Based on the traffic volume corresponding to the data packet, calculate the energy required to transmit the data packet,
Obtaining the residual energy of the intermediate node by calculating the difference between the energy of the intermediate node and the energy required for transmission of the data packet;
It is determined whether or not the residual energy of the intermediate node is equal to or higher than the lower limit of the energy, and if it is equal to or higher than the lower limit, it is determined that the energy of the intermediate node can satisfy the transmission of the data packet this time. 8. The route establishing method according to claim 3, claim 5, or claim 7, characterized by the above. Set the maximum energy consumption rate in advance,
It is determined that the energy of the intermediate node can satisfy the transmission of the data packet this time.
Based on the traffic volume corresponding to the data packet, calculate the energy required to transmit the data packet,
Calculating the ratio of the energy required for transmission of the data packet to the energy of the intermediate node;
Determining whether each of the calculated ratio values is smaller than the consumption rate of the highest energy, and if it is smaller, determining that the energy of the intermediate node can satisfy the transmission of the current data packet. 8. The route establishment method according to claim 3, claim 5, or claim 7. Set the minimum energy remaining rate in advance,
It is determined that the energy of the intermediate node can satisfy the transmission of the data packet this time.
Based on the traffic volume corresponding to the data packet, calculate the energy required to transmit the data packet,
By calculating the difference between the energy of the intermediate node and the energy required for transmission of the data packet, the surplus energy of the intermediate node is obtained, the ratio of the residual energy and the initial energy of the corresponding intermediate node is calculated,
It is determined whether each of the calculated ratio values is equal to or higher than the remaining rate of the minimum energy, and if it is equal to or higher than the remaining rate, it is determined that the energy of the intermediate node can satisfy the transmission of the current data packet. 8. The route establishment method according to claim 3, claim 5, or claim 7, comprising:   10. The route establishing method according to claim 1, 4, 8, or 9, wherein broadcasting the RREQ is broadcasting the RREQ according to all probabilities. Set the energy level and the broadcast probability corresponding to each energy level in advance,
Broadcasting the RREQ
Determine an energy level corresponding to the difference between the energy of the intermediate node that broadcasts the RREQ and the energy required for transmission of the data packet, or the energy level required for transmission of the data packet and the energy of the intermediate node Determining an energy level corresponding to the ratio, or determining an energy level corresponding to a ratio between the energy of the intermediate node and the energy required for transmission of the data packet and the initial energy of the intermediate node;
10. The route establishment method according to claim 4, wherein the RREQ is broadcast according to a broadcast probability corresponding to the energy level.   2. The method according to claim 1, further comprising: before step A, the source node receiving a data packet to be transmitted this time and determining a traffic amount and a destination node corresponding to the data packet. Route establishment method.   3. The route establishment according to claim 2, wherein before the determination in step B, the method further includes that an intermediate node that has received the RREQ updates its route information record based on the RREQ. Method.   Before the source node transmits a data packet according to a path in the RREP in step D, the method further comprises the source node updating its path information record based on the RREP. 17. The route establishment method according to claim 2, claim 15, or claim 16.   Before executing Step C in Step B, the method determines whether or not the intermediate node that has received the RREQ has received the RREQ for the first time, and if the RREQ is received for the first time, the method discards the RREQ. 2. The method according to claim 1, further comprising: returning to the determination in step B, and if not, executing step C subsequently.

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