KR20050102714A - Apparatus and method for transmitting the data by optimum path determination in the mobile ad-hoc network - Google Patents

Abstract

The present invention relates to a mobile ed hoc network capable of communicating between mobile nodes without a fixed base network. The present invention relates to a method for determining an optimal path for transmitting data from a source node to a destination node. Calculating a required power amount, transmitting a path search message including the calculated power amount information to a neighbor node of the source node, and when the remaining power amount at the neighbor node receiving the path search message satisfies the required power amount Transmitting the route discovery message to a next neighbor node, and when the route discovery message is transmitted to a destination node, generates a route setup response message at the destination node and transmits the reverse route to the reverse route of the route to which the route discovery message is transmitted; And a routing response message transmitted through the reverse path. From the received source node characterized in that it comprises the step of determining an optimum route by referring to the routing response message.

Description

Efficient Data Transmission Apparatus and Method by Optimal Path Determination in Mobile Ed-Hok Networks {APPARATUS AND METHOD FOR TRANSMITTING THE DATA BY OPTIMUM PATH DETERMINATION IN THE MOBILE AD-HOC NETWORK}

The present invention relates to a data transmission method in a mobile ed hoc network capable of communicating between mobile nodes without a fixed base network. More particularly, the present invention relates to a power shortage and a communication node of mobile nodes that may occur in a mobile ed hoc network. The present invention relates to an apparatus and a method for transmitting data in a mobile ad hoc network for effective communication in response to a path disconnection due to mobility.

In general, mobile ad hoc networks are technologies that allow communication between mobile nodes without a base station or a wireless access point, unlike conventional wireless communication. It was mainly used at disaster sites. Because of the portability and communication between heterogeneous terminals, it is a technology that is being expanded to use for civilian use.

The communication methods in the above-described mobile ed-hoc network are classified into a pro-active (pro-active or table-driven) method and a re-active (re-active or on-demand) method. The pro-active method is a method of configuring a path in advance before starting communication and checking the connection state of mobile nodes from time to time, such as a DSDV (Destination Sequence Distance Vector) method and a Wireless Routing Protocol (WRP) method.

The DSDV is a representative pro-active protocol. Based on the Bellman-ford routing algorithm, all nodes in the network always maintain information about the destination node in the routing table, and use sequence numbers to route routing. This is an improved protocol to avoid the problem. In addition, although the pro-active method has an advantage of effectively coping in terms of initiating a fast communication and managing a path in terms of configuring a path in advance, there are many control messages because information must be exchanged between mobile nodes from time to time. Power consumption is also high.

On the other hand, the re-active scheme includes a dynamic source routing protocol (DSR) scheme and an ad-hoc on-demand distance vector (AODV) scheme to configure a path when there is data to be sent from a source node. . The route search using the DSR method transmits a Route Request (RREQ) packet to the entire network when the start node wants to search the route to a certain destination node. When the RREQ packet reaches the destination, the destination node sends a Route Reply (RREP) message to the departure node as a response message.

In addition, the AODV method is a protocol that enables routing path avoidance by adding the path search algorithm of the DSR and the sequence number algorithm of the DSDV, and more effectively manages the path through the management of the routing table.

Compared to the pro-active method, the above-described re-active (ie, on-demand) method configures a path only when necessary, thereby reducing control messages and thus reducing power consumption. have. However, it is possible to cope with dynamic network changes and to effectively use bandwidth, and thus it is being steadily researched compared to the pro-active method.

On the other hand, in a mobile ad hoc network, a protocol for maintaining a node's lifespan and improving power efficiency is required. In the proposed protocols, the most important considerations are the optimal path setting in terms of the shortest hop and the method of selecting the path with the largest sum of power of each node. However, they do not route in terms of power efficiency, which can lead to unpredictable path breaks. In addition, in the mobile ED hoc network, each mobile node uses itself as a relay node, and thus a power shortage occurs, and because the network is dynamic, unexpected mobility occurs. If this is not effectively dealt with, the mobile node may stop working and eventually the network may split.

Accordingly, an object of the present invention is to configure an optimal communication path through a path search technique for reducing path disconnection due to power shortage and mobility of mobile nodes in a mobile ed hoc network, and a cost calculation method that optimally uses the state of the network. An apparatus and method for transmitting data in a mobile ed hoc network are provided.

In addition, an object of the present invention is to provide reliable management of data transmission of a dynamic mobile ad hoc network, in order to effectively manage a path for detecting a network state and a disconnection of an unexpected path even during data transmission in a mobile ad hoc network. It is an object of the present invention to provide a data transmission apparatus and method in a mobile ad hoc network.

The method of the present invention for achieving the above object; In a mobile ad hoc network capable of communicating between mobile nodes without a fixed base network, an optimal path determining method for transmitting data from a source node to a destination node, the method comprising: calculating an amount of power required to transmit the data; Transmitting a path search message including the calculated required power amount information to a neighbor node of the source node; and if the remaining power amount in the neighbor node receiving the path search message satisfies the required power amount, the next neighbor node; Transmitting a route discovery message, generating a route setup response message at the destination node when the route discovery message is transmitted to the destination node, and transmitting the route discovery message to the reverse path of the route where the route discovery message is transmitted; Source node receiving routing response message sent in reverse path The method may include determining an optimal path with reference to the path setting response message.

The apparatus of the present invention for achieving the above object; In a mobile ad hoc network capable of communicating between mobile nodes without a fixed base network, an optimal path determining apparatus for transmitting data from a source node to a destination node, the apparatus for calculating an amount of power required to transmit the data An optimum path for receiving a path setting response message from the destination node in response to a required power calculator and a path search message including the calculated required power amount information, and determining an optimal path with reference to the received path setting response message; And a selector.

DETAILED DESCRIPTION Hereinafter, a detailed description of a preferred embodiment of the present invention will be described with reference to the accompanying drawings. In the following description, when it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The present invention is based on the above-described Re-active (On-demand) scheme of configuring a path when communication is started, and implements data transmission in the ed hoc network according to the present invention described below efficiently and reliably. Specifically, the following methods are proposed.

1. A method of searching for a path in consideration of residual power of each mobile node.

2. Increased path survivability by forwarding packets through a path made up of nodes with sufficient residual power.

3. Efficient Path Computation A method of selecting optimal paths considering power and mobility of mobile nodes using cost relations.

4. A method of managing paths that can effectively cope with errors that may occur during data transmission.

5. How to secure multiple paths in case of link break.

6. How to provide reliability to the network through GPS positioning and mobility prediction.

Before describing the present invention, the main terms used in the description and their meanings are defined as follows.

Mobile Ad-hoc Networks: A network that allows mobile nodes to communicate cooperatively with each other without a fixed base station.

-Mobile Node, Communication Node: A device that is mobile and includes a routing function, and performs a communication function in an ed hoc network.

Sequence Number: A number generated by each mobile node at regular time intervals. The sequence number can be used to distinguish new information and to avoid duplicate message routing and routing loops.

-Source Node: It is the subject node to transmit data and becomes the starting point.

-Destination Node: The node that received the data and becomes the destination.

Link-break: When each node loses its path connection to communicate with its neighbors.

-Route Request (RREQ) message: A message containing information for searching a route in AODV and DSR protocols.

-RREP (Route Reply) message: A message used by the destination node in response to the RREQ of the source node.

Routing-Table, Node Information Table: A table containing information about the networks maintained by each node.

In addition, three control messages to be newly defined for the implementation of the present invention are as follows.

Route search message (PCRRQ (Power Constraint Route Requet) message): Control message containing information for searching the route in the present invention.

Routing reply message (PCREP (Power Constraint Route Reply message)): a response message of a destination node to the PCRRQ message sent from a source node to search for a route.

-Error occurrence message (RERR (Route Error message)): Warning and report message about error situation that may occur during data transmission.

The present invention sets the path in consideration of the remaining power amount of each mobile node in order to select the most power efficient path among all nodes that can be generated from the source node to the destination node. Accordingly, the source node compares the amount of remaining power for all mobile nodes passing through the PCRRQ message defined above to the destination node.

In addition, when transmitting a PCREP message, which is a response message to the PCRRQ message from the destination node to the source node, the information on the remaining power and the information on the estimated movement time for each mobile node to pass through to determine the minimum for each path The remaining power information and the minimum movement prediction time information are updated.

The source node calculates a path cost from a plurality of PCREP messages received for each path by using a calculation formula described below, and selects an optimal path according to the calculated path cost.

On the other hand, even after the optimal path is established, as described above, if the situation of the path is not good due to the lack of remaining power of each mobile node and the movement of the node, the optimal path may be reset through the RERR message.

Hereinafter, the above-described methods according to the present invention will be described in detail for each item.

<Requirements and Energy Models for Mobile Nodes>

In order to implement a technology for improving power efficiency and transmission reliability according to the present invention, each mobile node that transmits data can know information about its remaining power and can know its physical location information. Have a Global Positioning System.

1 is a diagram illustrating a process of delivering a route discovery message to a destination node in a mobile ed hoc network according to the present invention, and FIG. 2 is a diagram illustrating a configuration of a wireless communication terminal device in a mobile ed hoc network according to an embodiment of the present invention. The figure shown.

1 and 2, first, a source node 100 that wants to start a communication first searches for route information on a destination to which data is to be sent to its destination-specific route information database 220. If there is no valid information after the search, the required energy according to the size of the data to be processed is calculated through the required power calculator 240 in the source node 100 as shown in Equation 1 below.

here Is the size of the packet to be processed, Is the power consumed by the WLAN card, and BW is the bandwidth. The source node 100 determines the energy required at each mobile node using Equation 1 above.

Then, in the present invention, Equation 2 is used to perform power control according to the distance at the time of transmission of the data packet.

In Equation 2, k represents attenuation rate according to a communication environment, d represents a distance between nodes, and ?? has a value of 2 to 4 as a factor according to the environment. After k is calculated using Equations 1 and 2, power control according to distance is performed. On the other hand, when receiving and processing data, energy consumption is required to be about 1/50, because energy consumption is smaller than transmission energy. Shall be.

Therefore, the energy required for each node to transmit n packets is expressed by Equation 3 below.

The source node 100 to which data is to be transmitted is represented by Equation 3 above. After determining the value, the value is recorded in the path discovery message (ie, PCRRQ message) transmitted from the source node.

<Exploring Process of Data Transfer Path>

The present invention performs the function described below in order to use the energy of the mobile node efficiently.

The source node that wants to search the communication path calculates the required power quantity (REQ _p ) through Equation 1 and then generates a power constraint route request (PCRRQ) message to generate the path. Write to field 110.

On the other hand, the PCRRQ message according to the present invention can be configured in the form as shown in Table 1 below.

Packet field Explanation Type Packet Type 1: PCRRQ REQ _p The amount of power required for the entire data processing on each node Hop count Number of hops between source and destination nodes PCRRQ ID Serial number that generated the PCRRQ (duplicate acknowledgment) Destination IP Address Address of the destination node that the PCRRQ should reach Destination Sequence Number Serial number that issued PCREP at the destination node Source IP Address Address of the node that generated the PCRRQ Source Sequence Number Serial number that generated the PCRRQ at the source node

In the PCRRQ message generated as shown in Table 1, the PCRRQ ID uses a value increased by 1 from a recently used value. In addition, the source node 100 transmits the PCRRQ message to its neighboring mobile nodes (120). In addition to the header of the PCRRQ message, the TTL (Time To Live) value indicating the lifetime of the message varies depending on the size of the network. In the present invention, the node must search for power support of each node in the path discovery procedure, and the number of mobile nodes. In order to obtain the effect of multi-hop transmission according to the distance and distance, it is desirable to increase the TTL value compared to the conventional on-demand method.

The neighbor nodes receiving the PCRRQ message compare the PCRRQ ID with the address of the source node to determine whether the message is a duplicate message. If the message is a duplicate, discard it. On the other hand, if the received PCRRQ message is new information, it compares the required power amount of the PCRRQ and its own remaining power amount. If the remaining amount of power is greater than the required power (130), it determines itself as a supportable node and continues to retransmit the PCRRQ message to its neighbor node. If the remaining power amount does not satisfy the required power amount (140), the PCRRQ message is discarded.

In the conventional path search process, the path search message is sent to the destination node 160 through all nodes without considering the power of all mobile nodes. However, as described above, in the path discovery process proposed by the present invention, only nodes capable of supporting stable amount of power continue to send a message, thereby reducing power consumption and unnecessary control packet flow.

Optimal routing response process

When the PCRRQ message arrives from the source node 100 and reaches the desired destination node 160 by the above-described method, the corresponding destination node 160 sends a routing response message (ie, a PCREP message) to the source node 100. Should send. Accordingly, the destination node 160 having received the PCRRQ message compares the destination address 160 with the desired node on the source node 100 side, and if it is the desired destination node 160 at the source node 100, PCREP A PCRRQ Route Reply message is generated as shown in Table 2 below.

Packet field Explanation Type Packet Type 2: PCREP Hop count Space to store hop count (decremented by 1 when forwarding to reverse path) Destination IP Address Address of node that created PCREP Destination Sequence Number Serial number that issued PCREP at the destination node Source IP Address Address of the source node to receive PCREP Min (RESp) Information on residual power obtained as PCREP is delivered Min (PLT) Minimal Position Life Time Obtained by PCREP Delivery Position (x, y) Physical location of the mobile node (changes each time) Path record Information of the passthru nodes obtained through the reverse route (added at each node) Distance The distance between each node that PCREP gets (added by each node)

At this time, the destination sequence number is increased by 1 to its current value and then transferred back to the source node through the reverse path. The PCREP message plays a role of collecting data necessary for a relation that selects an optimal path while passing through a reverse path.

4 is a diagram illustrating a process in which a PCREP message collects information for optimal path setting through a reverse path according to an embodiment of the present invention.

Referring to FIG. 4, when the PCREP message is transmitted from the destination node 160 to the source node 100, each mobile node 410, 420, 430, and 440 passing through selects the optimal path. Collect and update materials needed for.

At this time, the data collected while the PCREP message is transmitted is as follows.

(1) As the PCREP message is transmitted in the reverse path, each node updates its own value if the values of the remaining power field and the estimated movement time field of the received PCREP packet are larger than their own measurements, referring to the information they have. . Therefore, in the two fields of the PCREP returned to the source node, the value of the node having the smallest remaining power and the movement prediction time PLT among the nodes on the path is recorded. The reason why the smallest value is recorded as described above is because the lifetime of the configured path has a decisive influence on the node having the smallest value.

(2) The movement prediction time (PLT) value of each node may be obtained by using GPS information and Equation 4 below.

In Equation 4, V is a moving speed of the mobile node, and can be obtained as a past mobility tendency. The S value is represented by Equation 5 in the movement prediction time meter 234 of FIG. 2 by using a difference between a WLAN propagation reach distance and a neighboring node among nodes constituting the current routing table path. To calculate.

In Equation 5 above Is a WiFi radio range, Is the distance between two nodes. Meanwhile, the distance between the two nodes Is calculated by Equation 6 below.

Equation 6 represents two mobile nodes Wow Find the distance of. The distance measurement is obtained using the inter-node distance measurer 233 of the controller 230. In the present invention, a process of acquiring information necessary for selecting an optimal path through the process of acquiring information is performed.

In FIG. 4, since RES _P is 40 at the mobile node E 440 and Min (RES _P ) included in the PCREP message is 50, the Min (RES _P ) is modified to 40. In the same manner, when the PCREP message is transmitted to the source node via the mobile node D 430, the mobile node C 420, and the mobile node B 410, Min (RES _P ) and Min (included in the PCREQ message are transmitted. PLT) values are determined to be 40 and 30, respectively. In addition, distance information between each mobile node is added whenever passing through the mobile nodes.

<Method of Calculating Cost for Optimal Path Setting>

In the present invention, a cost calculation relation described below for setting an optimal path is used. The optimal path selection method based on the existing on-demand protocol was decided mainly considering the shortest hop or shortest distance and response time. However, such a method has a high possibility of generating an error during data transmission because of low consideration of power life and mobility of the mobile node. Therefore, in the present invention, the optimal route is selected by calculating the route cost according to Equation 7 below.

Equation 7 is an equation used to set an optimal path in the present invention. The above algorithm is obtained through the optimal path selector 250 of FIG. h is the number of hops in the path, Is a weight value to match the weight of each other because the unit of each element does not match. The ?? value can be given by the user.

The path cost of Equation 7 is calculated by the optimal path selector 250 of FIG. 2, and the calculation of each term is performed by each calculation module of FIG. 3.

FIG. 3 is a diagram illustrating an optimal path selector structure of a wireless communication terminal device in a mobile ed hoc network according to an embodiment of the present invention.

In Equation 7, the first term The minutes are obtained by calculating the energy consumption according to the number of transmission hops and the distance between nodes. The calculation is obtained through the node consumption energy calculator 310. The above formula consists of the transmission energy per packet according to the distance and the energy calculation part to process when receiving one packet at each node. Therefore, the calculation is determined based on the distance information and the number of hops between the nodes of the PCREP message in response to the PCRRQ message. Meanwhile, the smaller the calculated value is, the smaller the power consumption is during packet transmission. In the present invention, the transmission power is determined by the above-described method to obtain the effect of the multi-hop effect and the power control according to the distance.

5 is a view showing the power saving effect through multi-hop transmission according to an embodiment of the present invention.

Referring to FIG. 5, the power consumption when transmitting a packet through the A path 510 is obtained through Equation 1. Power consumption and transmit over the B path 520 Consumes power. Thus, there is an equivalent distance but a significant difference in energy consumption. Of course, the increase in the number of nodes constituting the path Although the value increases, it is not a value that has a big effect on the gain obtained during transmission.

Meanwhile, the second term of Equation 7 Is an element for determining the power life of the selected path. The value is obtained through the power life prediction calculator 320. The larger the result value, the more margin is there in terms of the remaining path power. Where above Is a limit to exclude nodes with excessive residual power values.

Finally, the third term of Equation 7 Is the part for estimating the mobility of the node. This value is obtained through the node mobility prediction calculator 330. The purpose of this feature is to reduce power consumption and reduce transmissions by reducing the number of re-links caused by the mobility of nodes in a dynamic ed-hoc network, resulting in reliable transmission. By using this equation, the present invention can minimize the disconnection of the link due to the mobility of the node. On the other hand, of the above formula Is a limit value for excluding a node having a PLT value that is relatively too large compared to other nodes.

Using Equation 7, the total sum for each path can be used to calculate the cost of one or more paths. The calculated result value is advantageous to have a small value. Therefore, the source node is selected by the cost values calculated by the optimal route selector 340, sorted in order of having the optimum conditions for the possible routes, and recorded in the route information database 220 for each destination, and the first selected route. Send the packet to the destination via. This cost calculation allows the source node to have one or more paths for stable communication. These paths are used as bypass paths when link breaks occur or are expected.

<Path management procedure>

Mobile ED hoc networks often have a broken link because the network is dynamically configured in a wireless network. The causes of link disconnection include node mobility and inability to transmit data due to lack of residual power. This results in delays due to lost packets and rerouting and unnecessary power consumption. The present invention adds a new function to the existing Re-active path management mechanism to more effectively cope with the occurrence of errors, and provides power efficiency improvement and reliable transmission by using the bypass path obtained during path search.

6 is a diagram illustrating an RERR message and an error recovery procedure of a node that receives the RERR message according to an embodiment of the present invention.

Referring to FIG. 6, the path management performed in the present invention generates an error message (RERR) for link disconnection prediction while periodically predicting mobility using the remaining power of each mobile node and GPS information while transmitting data. In this case, two techniques are used to check the connection status with its own peripheral nodes and to generate RERR for link disconnection. This function is implemented through the transmission error manager 235.

Meanwhile, the RERR message can be configured as shown in Table 3 below.

Packet field Explanation Type Packet Type 3: Route Error Report (RERR) Type of Error (Binary Flag) 00: Expect lack of node power 01: Expected break of path due to mobility 10: Link-Break occurred without notice Destination count The number of unreachable nodes Out Node IP Address Address of unreachable node Out Node Destination Sequence Number Serial number of unreachable node

First, the situation where the RERR message occurs is a case where the current path is maintained (620). In this case, an error message is generated before the error occurs so that the source node uses an alternate path for the next packet transmission. At this time, an error is indicated in two RERR packets with two binary flags (ie, 00, 01) and sent to the source node. 00 Flag is a prediction of the lack of remaining power of the node. This function is possible in the present invention because the mobile nodes can predict their remaining power. In addition, since the mobile ed hoc network is composed of hop-to-hop, several nodes can use themselves as intermediate intermediary nodes.

On the other hand, even when the required power is satisfied during the initial path search, remaining power may be insufficient if another source node uses itself as an intermediate pass node. At this time, RERR is generated at the node where the remaining power shortage is expected and transferred to the higher node toward its source node. The parent node receives this and continues to send RERR messages to the source node.

01 Flag is a warning that the link will be disconnected soon beyond the communication propagation radius with neighbor nodes due to the mobility of the node. This value is the same concept as PLT during cost calculation.

On the other hand, although the source node knows the minimum travel prediction time of the path currently being used through PCREP, a node that is not reported or an initially reported node may suddenly go out of the propagation radius and a link break may occur. The node that is supposed to be disconnected records an error flag of RERR as 01 and sends an error message to the source node. This prevents the loss of packets due to sudden link breaks.

Finally, the node that received the error message determines that the already delivered packet has been delivered to the destination node until the RERR message is received, and does not perform an error recovery procedure. Prior to this, the source node must periodically perform a simple procedure to verify that its bypass path is valid. If the bypass path is not valid, re-search is performed.

In the second case, an unexpected link break occurs toward the destination node (610). Error detection is determined by whether each node responds when it sends periodic confirmation messages (a beacon signal is available) to its subnodes (destination node side). If the answer is not answered even after sending the confirmation message more than two times, it is determined that the link is disconnected, the flag of the RERR message is recorded as 10, and the RERR is sent to the upper node (source node direction). The source node receiving the message can selectively perform the error recovery procedure of the transmission packet. If the obtained bypass path is valid, the source node performs a new transmission through the bypass path.

That is, referring to FIG. 6, although the optimal path between the source node 600 and the destination node 601 is set as the path A 660, one node of one of the intermediate mobile nodes constituting the path A 660. Since the above-described problem occurs and the reliability of the path 630 or the path 640 falls, the path B 670, which is the next optimal path, is selected and transmitted as the optimal path.

Hereinafter, the above-described message transmission and reception procedure according to the present invention will be described with reference to FIGS. 7 to 10.

7 is a flowchart illustrating a data transmission procedure through optimal path setting according to an embodiment of the present invention.

Referring to FIG. 7, when data to be transmitted through the ad hoc network is generated (710), first, whether there is destination route information is checked (720).

As a result of the check, if there is preset destination route information, data is transmitted 730 according to the preset destination route information. If there is no preset destination route information, the optimal destination route information for data transmission is generated according to the present invention described above.

In order to generate the optimal destination path information, the source node first calculates the required amount of power for transmission as described above (740). The path discovery message as shown in Table 1 is generated by including the calculated required amount of power information (750), and the generated path discovery message is transmitted to the destination node through the neighboring node (760).

The destination node receiving the route discovery message generates a route setup response message and transmits it to the source node. The source node receiving the path setting response message 770 sets the path of the optimal condition with reference to the received path setting response message (780). Finally, the source node transmits data 790 along the path of the set optimal condition.

8 is a flowchart illustrating a path discovery message processing procedure received by a mobile node according to an embodiment of the present invention.

Referring to FIG. 8, each node that receives the path discovery message from the source node or the neighbor node (810) checks whether the received path discovery message is a duplicate message. If it is determined that the message is a duplicate message, the received path discovery message is discarded (840).

On the contrary, if the received path discovery message is not a duplicate message, it is checked whether the remaining power amount satisfies the required power amount required by the source node (830). If the remaining power does not satisfy the required power as a result of the inspection, it is preferable to discard the corresponding path discovery message because the data transmission through the corresponding node is not effective.

If the remaining power amount satisfies the required power amount, the received path discovery message is transmitted to the next node (850).

9 is a flowchart illustrating a procedure for transmitting a route establishment response message in a mobile node according to an embodiment of the present invention.

Referring to FIG. 9, when the route discovery message is transmitted to the destination (910) by the method described above with reference to FIGS. 7 and 8, the destination node sends a route establishment response message (PCREP) in response to the route discovery message. It generates in the form as shown in Table 2 (920). The generated route establishment response message is then transmitted 930 via each mobile node via the reverse route of the route through which the route discovery message was sent.

Meanwhile, each mobile node compares the above-described RES _p value and PLT value and records a small value in the routing response message (940). In addition, the mobile node adds the physical distance information of each mobile node to the routing response message (950). Each mobile node processed as described above transmits the routing message to the next mobile node (960).

10 is a flowchart illustrating an optimal path setting procedure by a path setting response message according to an embodiment of the present invention.

Referring to FIG. 10, the source node that finally receives the path setting message transmitted as shown in FIG. 9 calculates 1010 node consumption energy of each node in order to set an optimal path. Then, the source node calculates 1020 a power life prediction value for each node, and calculates a node mobility prediction value 1030 for each node. The calculated value is finally calculated by using Equation 7 to calculate a cost value for each node (1040).

The source node selects 1050 an optimal path based on the cost value calculated for each node. Then, the path information is stored in the database for each destination in the order of the optimal value for each node (1060).

On the other hand, in the embodiment of the present invention has been described with respect to specific embodiments, various modifications are possible without departing from the scope of the invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the appended claims, but also by those equivalent to the claims.

The present invention calculates the required power amount according to the size of data to be processed when searching for a data transmission path and configures a path with nodes with sufficient power to process the corresponding data, and excludes nodes that do not meet the conditions. It has the advantage of reducing power consumption.

 In addition, by using a path cost calculation equation that optimally uses the state of the network, it is possible to effectively use the battery power, which is a big limitation in the wireless environment, and to select an optimal path considering mobility in a dynamic ED hoc network.

In addition, with path management and error message generation technology that can effectively cope with node mobility and remaining power shortage that can occur during data transmission, it can effectively cope with the link disconnection that can occur during data transmission, reducing unnecessary power consumption, and providing reliability to users. It has the advantage of being able to do that.

1 is a diagram illustrating a process of delivering a route discovery message to a destination node in a mobile ed hoc network according to the present invention;

2 is a diagram illustrating a configuration of a wireless communication terminal device in a mobile ed hoc network according to an embodiment of the present invention.

3 is a diagram illustrating an optimal path selector structure of a wireless communication terminal device in a mobile ed hoc network according to an embodiment of the present invention.

4 is a diagram illustrating a process in which a PCREP message collects information for optimal path setting through a reverse path according to an embodiment of the present invention.

5 is a view showing a power saving effect through multi-hop transmission according to an embodiment of the present invention.

6 is a diagram illustrating an RERR message and an error recovery procedure of a node that receives the RERR message according to an embodiment of the present invention.

7 is a flowchart illustrating a data transmission procedure through optimal path setting according to an embodiment of the present invention.

8 is a flowchart illustrating a path discovery message processing procedure received by a mobile node according to an embodiment of the present invention.

9 is a flowchart illustrating a procedure for transmitting a route response message in a mobile node according to an embodiment of the present invention.

10 is a flowchart illustrating an optimal path setting procedure by a path setting response message according to an embodiment of the present invention.

Claims (10)

In a mobile ad hoc network capable of communicating between mobile nodes without a fixed base network, an optimal path determining method for transmitting data from a source node to a destination node, Calculating a required amount of power required to transmit the data, and transmitting a path discovery message including the calculated required amount of power information to a neighboring node of the source node; Transmitting the path discovery message to a next neighbor node when the amount of remaining power at the neighboring node receiving the path discovery message satisfies the required power amount; When the route discovery message is transmitted to a destination node, generating a route setup response message at the destination node and transmitting the reverse route to the reverse path of the route where the route discovery message is transmitted; And determining, by the source node receiving the path setting response message transmitted through the reverse path, an optimal path by referring to the path setting response message. The method of claim 1, And discarding the received path discovery message when the remaining power amount in the neighboring node that receives the path discovery message does not satisfy the required power amount. The method of claim 1, And if it is determined that the received route discovery message in the neighboring node that has received the route discovery message is a duplicate message, discarding the received route discovery message. The method of claim 1, The amount of power required to transmit the data is calculated as shown in Equation (8). here Is the size of the packet to be processed, Is the power consumed by the WLAN card, and BW is the bandwidth. The method of claim 1, Determining the optimal path through the received path setting response message, Calculating the energy consumption according to the number of transmission hops and the distance between nodes for each node; Determining the power life of the selected path for each node; Calculating the predicted value of the mobility of each node for each node, And calculating a cost value for each node based on the calculated values. The method of claim 5, The optimal path is determined as the node having the smallest cost value. The method of claim 5, The cost value is calculated by Equation 9 below. Where h is the number of hops in the path, Is a weight value to match the weight of each other because the unit of each element does not match. The ?? value can be given by the user. Also, the Is a limit for excluding a node having an excessive residual power value, Is a limit value for excluding a node having a PLT value that is too large relative to other nodes. In a mobile ad hoc network capable of communicating between mobile nodes without a fixed base network, an optimal path determining apparatus for transmitting data from a source node to a destination node, A power demand calculator for calculating an amount of power required to transmit the data; And a path setting response message received from the destination node in response to the path search message including the calculated required power amount information and determining an optimal path with reference to the received path setting response message. Said device. The method of claim 8, The device, And a destination-specific information storage database storing destination-specific forward path information for transmitting the data. The method of claim 8, The device, A node consumption energy calculator for calculating energy consumption according to the number of transmission hops and the distance between nodes for each node; A power life prediction calculator that determines the power life of the selected path for each node; And a node mobility prediction calculator for calculating a prediction value for the mobility of the node for each node.