KR20100070673A - Method for transmitting routing information in an wireless networks - Google Patents

Abstract

PURPOSE: A routing information transmitting method in a mobile network is provided to transmit reliably routing information between each node in order to improve performance of a routing protocol. CONSTITUTION: Routing information is periodically transmitted to at least one neighboring node(602). A message including a signaling sequence number is received from at least one neighboring node(604). Own signaling sequence number is updated by using the signaling sequence number within the received message(612). The routing information is retransmitted by using the updated signaling sequence number(614). In case an ACK message is not received from at least one neighboring node, the ACK message is requested(610).

Description

METHOD FOR TRANSMITTING ROUTING INFORMATION IN AN WIRELESS NETWORKS}

The present invention relates to a method for transmitting routing information in a wireless network, and more particularly, to a method for transmitting routing information between neighboring nodes.

In general, a routing technique in a network refers to a technique for establishing a path until data transmitted from a transmitting side reaches a receiving side. For example, routing in a multi-hop network is a network that allows a packet to be delivered to another node (router) to a destination node when the source node wants to send a packet to a destination node that is not directly connected to it. Function. To do this, the router receives traffic from one input port, finds the best-path to send packets to the other port, and sends it to the destination. In order for the router to determine the best path, it needs to know information about the topology of the network, which can be done by exchanging routing information between routers according to a defined protocol.

In general, in a wireless network system, routing information known by one node is transmitted in a broadcast manner because it must be known to all nodes in the vicinity. In a wireless network, since one node and neighbor nodes share a transmission medium, it is possible for all nodes of a neighbor to receive a packet at the same time in one transmission. However, since wireless networks have a greater effect of noise and interference than wired networks, and channel conditions change frequently, packets transmitted in a broadcast manner are not always received by all nodes. Accordingly, routing in a wireless network is performed by repeatedly transmitting routing information including the same information multiple times.

The conventional routing method is largely divided into a link state (hereinafter referred to as LS) method and a distance vector (hereinafter referred to as DV) method, and there are various modifications based on the above methods. The LS method is a method of determining the optimal path to an arbitrary destination node by notifying the entire network whenever a link state of a link is changed between two nodes so that all nodes in the network know the state of all links. On the other hand, in the DV method, each node stores an optimal path cost to each destination node in a routing table and exchanges contents of the routing table with each other, thereby delivering a packet to the destination node in an optimal path. In order to know which neighbor node to forward the packet to. Here, the neighbor node refers to a node that can directly transmit and receive packets without passing through other nodes.

Each node in the DV scheme periodically receives a routing table from a neighbor node. The routing table records the minimum cost for the node to send a packet to any destination. The purpose of the routing protocol is to select the path that always takes the least cost when sending any packet to any destination node, so each node sees the contents of the table sent by the neighbor nodes and sends the packet to any neighbor node for the given destination. You can tell if it should be delivered. In order to determine the least cost path, the cost value written in the neighbor node's routing table must be added to the cost for delivering the packet to the neighbor node. The sum of the costs will eventually deliver the packet through the neighbor node to the destination. It will be the minimum cost when it takes. Thus, the least cost path to a particular destination is the path that each node must choose to forward the packet. At this time, the minimum cost is the cost recorded in the routing table of the node. Since the routing table is broadcasted to the surroundings periodically, if the table contents of one node change, the change affects the table of neighbor nodes. These effects are transmitted sequentially throughout the network, so that even if the network topology changes, all nodes can eventually find new minimum cost paths.

Basically, the DV method broadcasts the contents of the entire table periodically to neighboring nodes regardless of changes in the routing table contents. Therefore, even if an error occurs in the transmission of a routing message temporarily, the routing table having the same contents is retransmitted in the next period, so that even if a problem caused by the transmission error occurs, the problem is limited to a temporary problem. However, the above scheme may excessively waste communication bandwidth by repeatedly transmitting unnecessary information. In addition, since the size of the routing table is proportional to the total number of nodes and the transmission period of the table is shortened in proportion to the rate of change of the topology, the waste of bandwidth becomes more severe when the number of nodes is large and the topology change is severe. Occurs.

Therefore, each node maintains a routing table and reliably transmits the routing information to all neighboring nodes, while eliminating unnecessary redundant transmissions, thereby improving the performance of the routing protocol and reducing the signaling overhead. Required.

The present invention is to solve the above-described problems of the prior art, to provide a method for reliably transmitting routing information between nodes in order to improve the performance of the routing protocol.

In addition, the present invention provides a routing information transmission method for minimizing signaling overhead by preventing unnecessary retransmission of routing information in a wireless network.

The present invention provides a method for transmitting routing information in a wireless network, the method comprising: periodically transmitting routing information to at least one neighboring node, receiving a message including a signal sequence value from the neighboring node, The present invention proposes a method for transmitting routing information including updating a signal sequence value of a transmitting node using a signal sequence value and retransmitting routing information using the updated signal sequence value.

The present invention can minimize signaling overhead by preventing unnecessary duplication of routing information in a distance vector based routing scheme. In particular, we propose a routing method that can efficiently transmit data in a mobile ad hoc network using low bandwidth and frequent topology changes.

In addition, the present invention is applicable not only for routing but also in all cases in which a plurality of nodes must periodically exchange a table composed of a plurality of entries.

In the following description of the present invention, detailed descriptions of well-known functions or configurations will be omitted if it is determined that the detailed description of the present invention may unnecessarily obscure the subject matter of the present invention. Terms to be described later are terms defined in consideration of functions in the present invention, and may be changed according to intentions or customs of users or operators. Therefore, the definition should be made based on the contents throughout the specification.

The present invention proposes a routing information transmission method for minimizing signaling overhead by preventing unnecessary transmission of routing information in a wireless network. Therefore, an embodiment of the present invention to be described later will be described in detail with respect to a method for efficiently transmitting and receiving a routing table between each node.

The present invention consists of a plurality of nodes making up a wireless network. Each node has a routing table to reference for routing decisions, and periodically broadcasts all or part of its routing table to neighboring nodes.

In addition, each node in the present invention has a neighbor node table for recording information about all its neighbor nodes.

Hereinafter, the structure of the routing table used in the preferred embodiment of the present invention will be described in detail.

1A shows a routing table conventionally used.

Referring to FIG. 1A, a routing table is composed of a plurality of entries having the same form, and one entry is composed of a plurality of fields required by a routing protocol. In general, each entry in the routing table contains information about one destination node, which includes the destination address and the optimal route cost from that node to the destination node.

1B illustrates a routing table according to a preferred embodiment of the present invention.

Referring to FIG. 1B, the routing table of the present invention has the same structure as the existing routing table, but there is a difference in that a signal sequence value is added to an entry constituting the routing table. The signal sequence value is a value indicating how recently the information of the entry has been updated. The signal sequential value of an entry first inserted into the routing table may have a predetermined initial value, and the initial value may be arbitrarily set by a user.

Apart from the signal sequence value of the above-mentioned entry, each node has two values: recently acknowledged signal sequence number (hereinafter referred to as LAS) and maximum signal sequence value (MaXimum signaling sequence number (hereinafter referred to as MXS)). Keep it.

At initial setup, all entries included in the routing table have the same initial signal sequence value. The MXS has a value equal to the initial signal sequence value, and the LAS has a value less than the initial signal sequence value. Each node uses the signal sequence values when broadcasting a routing message to a neighbor node. That is, each node does not include all the routing entries in the routing message (or routing information, and for the sake of convenience of description below), the routing table in which the signal sequence value satisfies a predetermined range. Contains only entries of. The predetermined range is a case where the signal sequence value of the entry satisfies the following equation.

LAS <signal sequence value of the entry ≤ MXS

If LAS = MXS at the node transmitting the routing message, it means that all nodes neighboring the transmitting node correctly received the most recently updated entry. In this case, the sending node does not include a routing table entry in the routing message. However, at the time of initial setting, since LAS + 1 = signal sequential value of the corresponding entry = MXS, according to Equation 1, all routing table entries are included in the routing message and transmitted. In addition, the current LAS and MXS values are recorded and transmitted in all routing messages. Every node periodically sends a routing message and at the same time receives a routing message.

According to a preferred embodiment of the present invention, in order for each node to operate as a receiving node, a neighbor signaling sequence number (hereinafter referred to as NSS) sequentially received from each neighboring node for all neighboring nodes is added to the neighboring node table. Record it. The sequentially received signal sequential value refers to a signal sequential value in which all signal sequential values are received without a number missing in the middle until the corresponding signal sequential value.

2 illustrates an NSS update method for operating each node as a receiving node according to an exemplary embodiment of the present invention.

Referring to FIG. 2, an NSS update method for a case where the NSS value for a transmitting node is greater than or equal to the LAS value of a received routing message will be described.

First, if the NSS value for a transmitting node is greater than the LAS value of the received routing message, the transmitting node sends a routing message to the receiving node that includes a routing entry that is greater than the LAS value and less than or equal to the MXS value. That is, since the LAS value of the routing message to be transmitted is 17 and the MXS value is 22, the transmitting node transmits a routing message including an entry having a signal sequence value of 18 to 22. The NSS value for the transmitting node is 19 until the receiving node receives the routing message. This means that the receiving node has received the routing message up to the entry corresponding to the signal sequence value 19 from the current transmitting node. If the receiving node receives a routing message from the transmitting node that includes an entry having a signal sequence value from 18 to 22, the NSS value for the transmitting node is updated with the MXS value of the received message. Therefore, the NSS value for the transmitting node of the receiving node is updated from 19 to 22.

Second, if the NSS value for the transmitting node is equal to the LAS value of the received routing message, then the transmitting node sends an entry with a signal sequence value of 18 to 22. At this time, the NSS value of the transmitting node of the receiving node is 17, the LAS value of the routing message transmitted from the transmitting node is 17 and the MXS value is 22. The receiving node updates the NSS value from 17 to 22 for the transmitting node because it has received a routing message with consecutive rank values.

Third, if the NSS value for the transmitting node is less than the LAS value of the received routing message, the transmitting node sends an entry with a signal sequence value corresponding to 18 to 22 to the receiving node. On the other hand, since the receiving node has an NSS value of 15, the receiving node has received a routing table entry having a signal sequence value of up to 15 before receiving the routing message including the entry. Therefore, since the receiving node has not received an entry having signal sequence values corresponding to 16 and 17, the receiving node does not update the NSS value until the signal sequence values corresponding to 16 and 17 are received.

As described above, when each node acts as a receiving node, it will update the NSS value to identify routing messages received from neighboring nodes to date. The updated NSS value is used to update the LAS value to be described later.

Hereinafter, a method of updating the LAS and MXS in order for each node to transmit routing information according to a preferred embodiment of the present invention will be described in detail.

First, the method of updating the MXS is to increment by 1 when there is an entry added or updated until each node transmits a routing message and then transmits the next routing message. The MXS value is maintained if no entry is added or updated when sending the next routing message. At this time, the entry to be added or updated has an increased MXS value as the signal sequential value. Even if there is an addition or update of an entry within the same period after the MXS value is increased by one, the MXS value does not increase further. In addition, all entries added or updated in the same period have the same signal sequence value.

For example, if the MXS value in period n is called MXS (n), and no entry is added or updated from period n + 1 to period n + m, then MXS (n) = MXS (n + 1) = .. = MXS (n + m). If there is an entry added or updated in the period n + m + 1, the signal sequence value of the entry is MXS (n + m + 1) = MXS (n) +1. In this case, if there are other entries added or updated in the period n + m + 1, those entries all have the same value as MXS (n + m + 1).

The node for transmitting the routing message configures the routing message by referring to the LAS value as well as the MXS value. A routing table entry having a signal sequential value less than or equal to the LAS value determines that all neighbor nodes have normally received the latest value. Accordingly, the node transmitting the routing message broadcasts to the neighboring nodes by including in the routing message an entry whose signal sequence value is greater than the LAS value and less than or equal to the MXS value.

There are two methods for updating the LAS value, a method using an acknowledgment (ACK) and a method using a negative acknowledgment (NACK). Hereinafter, a method of transmitting routing information using the above two methods will be described in detail.

First Embodiment

3 illustrates a method for transmitting routing information using an ACK message according to a first embodiment of the present invention. Referring to FIG. 3, a transmitting node transmits routing information using an ACK message received from each neighboring node.

When each node acts as a receiving node, the receiving node updates the NSS value for the corresponding transmitting node using the aforementioned NSS updating method. The updated NSS value is recorded in an ACK message and transmitted to the corresponding transmitting node. This is for the receiving node to inform that the routing message is normally received from the corresponding transmitting node. The receiving node may transmit an ACK message to each transmitting node individually, or may combine and transmit an ACK message and a routing message in one packet every cycle. Each transmitting node records the NSS value recorded in the last ACK message received from each neighboring node in the neighboring node table for all neighboring nodes. Each transmitting node refers to the neighbor node table before transmitting the routing message every cycle, and updates the smallest NSS value among the NSS values received from the neighbor nodes with the LAS value of the routing message.

If all previously updated table entries, including the most recently updated table entry, have been received successfully by all neighboring nodes, then all neighboring nodes receive the NSS value for that sending node, the MXS value recorded in the received message, ie. Update to the MXS value of the sending node. The updated NSS value is then informed to the transmitting node in an ACK message, and the transmitting node records the NSS values recorded in each ACK message in the corresponding neighbor node entry of the neighbor node table. If all ACK messages are normally received by the transmitting node, the NSS values of all neighbor nodes recorded in the neighbor node table are equal to the MXS values of the transmitting node. At this time, as described above, the LAS has the same value as that of the MXS, and the routing message transmitted thereafter does not include routing table information. That is, when all neighbor nodes sequentially receive up to recently updated routing table entries and ACK messages are normally received, no further routing information is transmitted until the next routing table update.

If some nodes have not received the recently updated routing information, those nodes do not send an ACK message for the recently updated signal sequence. Therefore, the NSS value for some nodes recorded in the neighbor node table of the transmitting node will have a value smaller than the MXS value of the transmitting node. For example, if the smallest value of the NSS values for some of the neighbor nodes is m, the transmitting node updates LAS = m at the next routing message transmission. Therefore, the transmitting node transmits routing table entries belonging to a range in which the signal sequential value of the corresponding entry is larger than the LAS value and smaller than or equal to the MXS value. Therefore, all routing information not received by some nodes is retransmitted.

At this time, although all neighbor nodes have received the routing message and transmitted an ACK message, some ACK messages may not be received by the transmitting node due to an error. At this time, the node transmitting the ACK message does not retransmit the ACK message for the same routing information received from the transmitting node. Therefore, there is a problem that the routing information retransmitted due to the loss of the ACK message is continuously retransmitted from the transmitting node. In order to solve this problem, when the first routing message is transmitted after updating a routing table, the transmitting node explicitly requests an ACK message for a neighbor node that has not received an ACK message for recently transmitted routing information. The neighbor node receiving the ACK message request retransmits the ACK message to the corresponding transmitting node.

A method of transmitting routing information using the aforementioned ACK message will be described with reference to FIG. 3.

If a transmitting node transmits a routing message to all neighboring nodes in the previous period N-1, the transmitting node receives an ACK message from each neighboring node in period N. At this time, the transmitting node records the NSS value recorded in the ACK message received from each neighboring node in the neighboring node table. NSS value 22 is recorded in the ACK message of the neighbor nodes 2, 3, and 4, NSS value 20 is recorded in the ACK message of the neighbor node 5, and NSS value 17 is recorded in the ACK message of the neighbor node 1. That is, neighbor nodes 2, 3, and 4 receive all of the routing information transmitted from the transmitting node, and the ACK message is also normally transmitted. On the other hand, neighbor node 5 has received a routing table entry up to signal sequence 20 from the transmitting node, and neighbor node 1 has received a routing entry up to signal sequence 17 from the transmitting node. The smallest NSS value among the NSS values received from neighbor nodes in the current period is updated with the LAS value of the transmitting node. Therefore, the LAS value of the routing message to be sent in the current period is updated to 17. Since the MXS value of the routing message in period N is 22, the transmitting node transmits routing information including all entries having a signal sequence value of 18 to 22 to all neighboring nodes.

In addition, in the current period, the transmitting node explicitly requests the ACK message from the neighbor node 1 and the neighbor node 5. This is because the neighbor node 1 and the neighbor node 5 may receive the routing information transmitted from the transmitting node legally, and then the ACK message transmitted to the transmitting node may be lost. The ACK request message transmitted by the transmitting node in the current period may be transmitted individually, or may be transmitted in one packet along with a routing message to be sent every cycle.

In period N + 1, neighbor nodes 1 and 5 that have received the ACK request message in the previous period retransmit the ACK message to the transmitting node. At this time, the transmitting node records the NSS value recorded in the ACK message received from the neighbor nodes in the neighbor node table. NSS value 22 is recorded in the ACK message retransmitted from the neighbor node 1, and NSS value 20 is recorded in the ACK message retransmitted from the neighbor node 5. That is, neighbor node 5 is still receiving a routing entry up to a signal sequence of 20. In the current cycle, the LAS value in the routing message is updated to 20, and the MXS value is 22 because no new entries have been changed in the current cycle. Thus, the transmitting node transmits routing information to all neighboring nodes, including entries having signal sequential values from 21 to 22. In addition, in the current cycle, the transmitting node explicitly requests the neighbor node 5 for the ACK message.

In a period N + 2, the transmitting node receives an ACK message having an NSS value of 20 from the neighbor node 5 and receives an ACK message having an NSS value of 22 from the neighbor nodes 1,2,3,4. When a newly changed entry occurs in the period, the transmitting node no longer requests the neighbor node 5 for an ACK message and transmits an entry corresponding to a signal sequence value of 21 to 23 to all neighbor nodes. After receiving the routing information transmitted from the transmitting node, the neighbor nodes record the NSS value for the transmitting node in an ACK message and transmit the same.

6 is a flowchart briefly illustrating a method of transmitting routing information according to a first embodiment of the present invention.

Referring to FIG. 6, in step 602, a transmitting node periodically broadcasts routing information to at least one neighboring node. Neighbors update the NSS value after receiving routing information from the transmitting node. If the updated NSS value is recorded in an ACK message and transmitted to the corresponding transmission node, in step 604, the transmitting node receives the ACK message.

In step 606, the transmitting node determines whether an ACK message has been received from all neighboring nodes. That is, it is checked whether the NSS value received from the neighbor nodes is the MXS value of the recently transmitted routing message. If the ACK message is not received from at least one neighbor node, in step 608, the transmitting node updates the MXS value and the LAS value to include an entry constituting a routing message to be resent in the next period. Thereafter, in step 610, the transmitting node transmits a routing message including an entry whose signal sequence value is greater than the LAS value and less than or equal to the MXS value. In operation 610, the transmitting node requests an ACK message from a neighbor node where the ACK message is not received. The routing message and the ACK request message transmitted every cycle may be composed of one packet and transmitted.

If an ACK message is received from all neighbor nodes in step 606, the flow proceeds to step 612. In step 612, the transmitting node updates the MXS value and the LAS value to construct a routing message to be transmitted in the next period. Thereafter, in step 614, the transmitting node transmits a routing message including an entry whose signal sequential value is greater than the LAS value and less than or equal to the MXS value.

If the ACK message is normally received from all neighboring nodes for the routing message recently transmitted by the transmitting node, the LAS value and the MXS value of the transmitting node are the same. Therefore, routing messages sent in the next cycle do not include routing table entries. However, even if all ACK messages are normally received, if a newly updated entry occurs in the routing table of the transmitting node, the newly updated entry is included in the routing message to be transmitted in the next period and transmitted to all neighbor nodes. This is because the MXS value increases by one when the new entry occurs.

According to the above-described routing information transmission method, if some nodes do not receive the routing information, an ACK message is not transmitted from the some nodes within a corresponding period. Therefore, if even one neighbor node does not receive the routing message, the transmitting node retransmits the routing information including the routing table entry that the some nodes did not receive. Unlike the existing routing table transmission scheme, signaling overhead can be reduced by preventing redundant transmission of the same information while maintaining the same transmission reliability.

Hereinafter, a method of transmitting routing information using a NACK message will be described in detail.

Second Embodiment

4 illustrates a method for transmitting routing information using a NACK message according to a second embodiment of the present invention.

Referring to FIG. 4, the transmitting node transmits routing information using a NACK message received from each neighboring node.

In an embodiment of the present invention, it is assumed that all routing information once transmitted from a transmitting node to neighboring nodes has been normally received. Therefore, if there is no explicit retransmission request from some neighbor node, it is not transmitted.

The node receiving the routing message reads the LAS value recorded in the routing message sent from the transmitting node. If the LAS value is less than or equal to the NSS value for the corresponding transmitting node, the receiving node does not respond to the transmitting node. This is because the signals are sequentially received up to the signal sequence value included in the currently transmitted routing message.

On the other hand, when the LAS value recorded in the routing message is larger than the NSS value for the corresponding transmitting node, the receiving node transmits a NACK message to the transmitting node. In the NACK message, an NSS value for a corresponding transmitting node is recorded. Similar to the ACK message described above, the NACK message may be sent as a separate message, or may be sent in one packet together with a routing message to be sent every cycle.

The transmitting node broadcasts the routing message to the neighboring nodes every cycle, and then initializes the NSS value for each neighboring node of the neighboring node table with its own MXS value. This is because, as described above, it is assumed that all routing information once transmitted to the neighbor nodes has been normally received. When any neighbor node receives the routing message from the transmitting node and subsequently receives up to the signal sequential value included in the message (that is, NSS for the transmitting node LAS ≤ ≤ in the routing message), the neighbor node does not respond. The NSS value of the neighbor node recorded in the neighbor node table maintains the initial value MXS.

On the other hand, when the routing message from the transmitting node is not sequentially received until the signal sequential value included in the message (that is, LAS> NSS for the transmitting node of the routing message), the receiving node receives the NSS for the transmitting node. Record the value in the NACK message and send it. When the transmitting node receives the NACK message, it records the NSS value recorded in the NACK message in the corresponding neighbor node NSS item of the neighbor node table. Accordingly, the transmitting node refers to the neighbor node table immediately before transmitting the next routing message, and updates the minimum NSS value of the NSS values of each neighboring node with the LAS value of the new transmitting node. The transmitting node constructs a routing message to be transmitted in the next period using the LAS value and the MXS value.

As such, if all of the NACK messages transmitted in the previous period are normally received, all routing table entries that one or more neighboring nodes have not received until the previous period are retransmitted. However, in the embodiment of the present invention, when the NACK message is lost during transmission, a separate NACK message request is not required.

A method of transmitting routing information using the aforementioned NACK message will now be described with reference to FIG. 4.

When an updated entry (entry with signal sequential values of 21 and 22) occurs in the routing table in period N, the transmitting node broadcasts routing information including the updated entry to all neighboring nodes. In the current cycle, the transmitting node changes its NSS value for each neighbor node in its neighbor table to its MXS value. That is, the transmitting node changes the NSS value for the neighboring node to the signal sequence value 22.

In the period N + 1, since the neighbor node 1 did not receive the routing information normally, the NSS value for the corresponding transmitting node is recorded in the NACK message and transmitted to the corresponding transmitting node. At this time, the transmitting node records the NSS value received from the neighbor node 1 in the neighbor node table. The smallest NSS value of the NSS values of each neighboring node is updated with the LAS value of the routing message to be transmitted by the transmitting node. That is, in period N + 1, the LAS value of the routing message to be transmitted by the transmitting node becomes 17. Thus, the transmitting node retransmits routing information including entries of signal sequence values 18 through 22.

In period N + 2, if a NACK message is not received from neighboring nodes and a newly updated entry occurs, the transmitting node broadcasts routing information including only the newly updated entry to all neighboring nodes.

7 briefly illustrates a flowchart for transmitting routing information according to a second embodiment of the present invention.

Referring to FIG. 7, in operation 702, the transmitting node periodically broadcasts routing information to at least one neighboring node. After receiving the routing information, any neighbor node determines whether the routing table entries have been sequentially received up to the signal sequence value included in the routing message. If the neighbor node receives the routing table entries sequentially (i.e., NSS for the LAS ≤ transmitting node of the routing message), no response is made to the corresponding transmitting node. On the other hand, when the neighbor node does not receive the routing table entries sequentially (ie, NSS for the LAS> transmitting node of the routing message), the NACK message is transmitted to the corresponding transmitting node. In the NACK message, an NSS value of a transmitting node of a corresponding neighboring node is recorded.

In step 704, the transmitting node receives a NACK message from a neighbor node requiring retransmission. The transmitting node records the NSS value recorded in the NACK message in the corresponding neighbor node NSS item of the neighbor node table. In step 706, the transmitting node updates the MXS value and the LAS value of the routing message to be transmitted in the next period. That is, the transmitting node refers to the neighbor node table immediately before transmitting the next routing message, and updates the minimum NSS value among the NSS values of each neighboring node with a new LAS value.

In step 708, the transmitting node retransmits routing information using the MXS and LAS values. In addition, if a newly updated entry occurs in the routing table of the transmitting node, the newly updated entry is included in a routing message to be transmitted in the next period and transmitted to all neighbor nodes.

In the aforementioned routing information transmission method, unnecessary retransmission does not occur, and a NACK message is transmitted only when retransmission is necessary. In addition, since the transmitting node does not need to request an explicit NACK message, the signaling overhead is reduced compared to the routing information transmission method using the ACK message. However, if transmission of the NACK message fails, retransmission of necessary routing information may not occur, which is less reliable than a transmission method using the ACK message.

Third embodiment

5 illustrates a method of transmitting routing information using a NACK message according to a third embodiment of the present invention.

Referring to FIG. 5, a transmitting node transmits routing information including only an entry requiring retransmission using a NACK message received from each neighboring node.

Each receiving node stores the signal sequence values that it has not received from the transmitting node for each transmitting node, and records the signal sequence values in the NACK message for transmission. At this time, the transmitting node incorporates a list of signal sequence values recorded in the NACK message transmitted by each receiving node and includes entries in the routing message in the next period having the signal sequence values included in each NACK message more than once.

A method of transmitting routing information using the aforementioned NACK message will now be described with reference to FIG. 5.

When an updated entry (entry with signal sequential values of 21 and 22) occurs in the routing table in period N, the transmitting node broadcasts the routing information including the updated entry to all neighbor nodes.

In period N + 1, neighboring nodes 1 and 5 write signal sequence values not received from the corresponding transmitting node in a NACK message and transmit them. The transmitting node merges entries corresponding to signal sequential values not received at neighbor nodes 1 and 5. Therefore, the transmitting node includes an entry corresponding to the signal sequence values 16, 17, and 18 in the routing message transmitted in the current period.

If a NACK message is not received from neighboring nodes in period N + 2 and a newly updated entry occurs, the transmitting node broadcasts routing information including only the newly updated entry to all neighboring nodes.

8 briefly illustrates a flowchart for transmitting routing information according to a third embodiment of the present invention.

Referring to FIG. 8, in step 802, a transmitting node periodically broadcasts routing information to at least one neighboring node. Each receiving node stores the signal sequence values that it has not received from the transmitting node for each transmitting node, and records the signal sequence values in the NACK message for transmission.

In step 806, the transmitting node integrates the signal sequence list recorded in the NACK message. Thereafter, in step 807, the transmitting node retransmits a routing message including only an entry corresponding to the integrated signal sequence value.

The above-described method for transmitting routing information is an improvement of the method for transmitting routing information according to the second embodiment of the present invention, and it is possible to further reduce signaling overhead by selecting and retransmitting only the entries requiring retransmission.

While the invention has been shown and described with reference to certain preferred embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and 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 claims below, but also by those equivalent to the claims.

That is, the above detailed description of the present invention shows an implementation for improving the routing information transmission method based on the distance vector method in a wireless network. However, the present invention can be applied in a manner that does not deviate significantly from the scope of the present invention even if the method of exchanging a table between neighboring nodes is different from the distance vector method. It will be possible in the judgment of a person with technical knowledge.

1A is a diagram showing a routing table conventionally used;

1B illustrates a routing table according to a preferred embodiment of the present invention;

2 is a diagram illustrating an NSS update method at a receiving node according to a preferred embodiment of the present invention;

3 is a diagram illustrating a routing information transmission method using an ACK message according to a first embodiment of the present invention;

4 is a diagram illustrating a routing information transmission method using a NACK message according to a second embodiment of the present invention;

5 is a diagram illustrating a routing information transmission method using a NACK message according to a third embodiment of the present invention;

6 is a flowchart for transmitting routing information according to the first embodiment of the present invention;

7 is a flowchart for transmitting routing information according to a second embodiment of the present invention;

8 is a flowchart for transmitting routing information according to a third embodiment of the present invention.

Claims (7)

In the method for transmitting routing information in a node constituting a wireless network, Periodically transmitting routing information to at least one neighboring node; Receiving a message including a signal sequence value from the at least one neighbor node; Updating its own signal sequence value using the signal sequence value in the received message; And And retransmitting routing information using the updated signal sequence value. The method of claim 1, The message is a routing information transmission method, characterized in that the ACK message. 3. The method of claim 2, And if the ACK message is not received from the at least one neighboring node, requesting the ACK message. The method of claim 1, The message is a routing information transmission method, characterized in that the NACK message. The method of claim 4, wherein The retransmission process includes integrating the signal sequence values recorded in the NACK message and retransmitting only the routing table entries corresponding to the integrated signal sequence values. The method of claim 1, The updated signal sequence value is a routing acknowledgment (Last Acknowlged signaling sequence number) and the maximum signal sequence value (MaXimum signal sequence number) characterized in that the routing information transmission method. The method of claim 6, The retransmitting may include retransmitting routing information including only routing table entries whose signal sequence value of the corresponding entry is greater than the recently responded signal sequence value and less than or equal to the maximum signal sequence value.

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