WO2009057863A1

WO2009057863A1 - Reliable and energy efficient data routing apparatus and method for sensor node in wireless sensor network

Info

Publication number: WO2009057863A1
Application number: PCT/KR2008/001565
Authority: WO
Inventors: So-Young Hwang; Chang-Sub Shin; Gwang-Ja Jin; Yoon-Mee Doh; Bong-Soo Kim; Cheol-Sig Pyo; Jong-Suk Chae
Original assignee: Electronics And Telecommunications Research Institute
Priority date: 2007-10-31
Filing date: 2008-03-20
Publication date: 2009-05-07
Also published as: KR20090044249A

Abstract

Provided is a reliable and energy efficient data routing apparatus and method for a sensor node in a wireless sensor network. The method includes: receiving route setup messages including residual energy information of each of one or more neighboring sensor nodes within a wireless reception range of the sensor node from the neighboring sensor nodes for a predefined reception waiting time; selecting a parent node for routing from among the neighboring sensor nodes according to the residual energy information of each of the neighboring sensor nodes; and transmitting the sensing data to the selected parent node. Accordingly, since a data transmission path is selected by considering residual energy, energy consumption can be dispersed across the wireless sensor network to extend the lifetime of the wireless sensor network and a detour can be used to improve data transmission reliability.

Description

RELIABLE AND ENERGY EFFICIENT DATA ROUTING APPARATUS AND METHOD FOR SENSOR NODE IN

WIRELESS SENSOR NETWORK

Technical Field

[1] The present invention relates to a reliable and energy efficient data routing apparatus and method for a sensor node in a wireless sensor network, and more particularly, to a data routing apparatus and method for a sensor node in a wireless sensor network by selecting a data transmission path in consideration of residual energy at each node to disperse energy consumption across the wireless sensor network and reliably transmit the data through a detour path.

[2] This work was supported by the IT R&D program of MIC/IITA[2005-S-038-03, Development of UHF RF-ID and Ubiquitous Networking Technology]. Background Art

[3] A sensor network refers to a wireless network consisting of sensor nodes having the ability to sense and process data and wirelessly communicate with other nodes and a sink node having the ability to collect data from the sensor nodes and being called a gateway or a base station. Such a sensor network can be widely used all over industry and particularly used in the following applications.

[4] First, the sensor network can be used in military applications such as unmanned surveillance and command. Second, the sensor network can be used in environmental applications such as pollution, forest fire, and flood monitoring, and cultivation-related environment diagnosis in rural areas. Third, the sensor network can be used in digital home applications such as remote control and crime prevention using smart sensors attached to electronic devices, illuminators, windows, etc. Fourth, the sensor network can be used in intelligent building applications such as automation and control through building monitoring and energy efficient management. Fifth, the sensor network can be used in medical applications such as patient monitoring, health care, drug management, and systems for the disabled. Finally, the sensor network can be used in physical distribution management and telematics applications such as product distribution management and quality management.

[5] In the applications of the sensor network, data sensed by a sensor node is transmitted to a sink node having the ability to collect data. However, when the data is transmitted, sensor nodes form an ad hoc network without using an existing network, and then transmit the data over the ad hoc network to the sink node.

[6] Accordingly, the sensor network should be designed to meet the following conditions. First, the lifetime of the sensor nodes should be maximized through low power consumption. Since the sensor nodes are often installed in locations that may be difficult to access and thus manual battery replacement is almost unrealistic, the lifetime of the sensor nodes should be maximized through minimum power consumption. Second, the sensor network should have mobility when a network topology is changed. The sensor nodes disposed in a sensor field are not directly connected to a fixed infrastructure network, such as the Internet, but communicates with one another after arbitrarily forming the ad hoc network and communications with external devices, such as the Internet, by using the sink node acting as a gateway. The network topology may be changed when the sensor nodes are moved or wrongly operated, or new nodes are added. Accordingly, the sensor network should be able to be adapted to the changed network topology. Disclosure of Invention Technical Problem

[7] Directed diffusion (DD) is a classical routing scheme for transmitting data from a source node to a sink node. The DD finds an optimal routing path between the sink node and the source node by considering energy at each node and transmits data through the optimal routing path. However, since the data is continuously transmitted through the optimal routing path, energy consumption is concentrated on nodes disposed in the optimal routing path.

[8] To solve the problem of the DD, energy aware routing (EAR) has been suggested.

The EAR is a routing scheme in which energy consumption is uniform across the network. Under the assumption that all nodes know their own locations and others' in advance, topology information ranging from a sink node to a source node is stored in a table of each node, each of sensor nodes between the source node and the sink node arbitrarily selects a next node in its own table, and paths are chosen according to nodes varying whenever data is transmitted, thereby preventing energy consumption from being concentrated on specific nodes. However, it is a burden to enable all the nodes to know the locations in advance. Also, when a data transmission failure has occurred, both the DD and the EAR have no measures to deal with it, thereby reducing reliability. Technical Solution

[9] The present invention provides a routing apparatus and method for sensing data of a sensor node in a wireless sensor network which can disperse energy consumption across the wireless sensor network by selecting a data transmission path by considering the residual energy of each node. Description of Drawings [10] The above and other features and advantages of the present invention will become more apparent by describing in detail exemplary embodiments thereof with reference to the attached drawings in which:

[11] FIG. 1 is a block diagram of a sensing data routing apparatus for a sensor node in a wireless sensor network according to an embodiment of the present invention;

[12] FIG. 2 is a flowchart illustrating a sensing data routing method for a sensor node in a wireless sensor network according to an embodiment of the present invention;

[13] FIG. 3 is a flowchart illustrating a method of setting a path based on a tree topology connecting sensor nodes to a sink node in a wireless sensor network according to an embodiment of the present invention;

[14] FIG. 4 illustrates the wireless sensor network in which the method of FIG. 3 is performed according to an embodiment of the present invention;

[15] FIG. 5 is a flowchart illustrating a method of transmitting data from a sensor node to a sink node in a wireless sensor network according to an embodiment of the present invention;

[16] FIG. 6 illustrates the wireless sensor network in which the method of FIG. 5 is performed according to an embodiment of the present invention;

[17] FIG. 7 illustrates a format of a route setup message according to an embodiment of the present invention;

[18] FIG. 8 illustrates a format of a reception acknowledgement message according to an embodiment of the present invention;

[19] FIG. 9 illustrates a format of a data message according to an embodiment of the present invention;

[20] FIGS. 1OA through 1OD illustrate a method of receiving a message of a sensor node according to an embodiment of the present invention; and

[21] FIG. 11 is a flowchart illustrating a method of transmitting a data message of a sensor node according to an embodiment of the present invention. Best Mode

[22] According to an aspect of the present invention, there is provided a sensing data routing apparatus for a sensor node in a wireless sensor network consisting of a sink node and one or more sensor nodes, the routing apparatus comprising: a route setup message receiving unit receiving route setup messages including residual energy information of each of one or more neighboring sensor nodes within a wireless reception range of the sensor node from the neighboring sensor nodes for a predefined reception waiting time; a parent node selecting unit selecting a parent node for routing from among the neighboring sensor nodes based on the residual energy information of each of the neighboring sensor nodes; and a sensing data transmitting unit transmitting the sensing data to the selected parent node. [23] According to another aspect of the present invention, there is provided a sensing data routing method for sensing data of a sensor node in a wireless sensor network consisting of a sink node and one or more sensor nodes, the routing method comprising: receiving route setup messages including residual energy information of each of one or more neighboring sensor nodes within a wireless reception range of the sensor node from the neighboring sensor nodes for a predefined reception waiting time; selecting a parent node for routing from among the neighboring sensor nodes based on the residual energy information of each of the neighboring sensor nodes; and transmitting the sensing data to the selected parent node. Mode for Invention

[24] The principles of the present invention will be shown hereinafter. Hence, although not shown or not clearly described, it should be understood by one of ordinary skill in the art that the principles of the present invention can be embodied and various devices included within the concept and scope of the present invention can be invented. Also, it should be understood that all terms and embodiments enumerated in the specification are only intended to explain the concept of the present invention and the present invention is not limited to the embodiments and states. Also, it should be understood that all detailed description of the exemplary embodiments is intended to include not only the principles, the aspects, and the exemplary embodiments of the present invention but also structural and functional equivalents thereof. Also, it should be understood that the equivalents include not only currently publicized equivalents but also equivalents to be developed in the future, that is, all devices to be developed to perform the same function irrespective of their structures.

[25] Functions of various devices that are illustrated in drawings including a function block denoted as a processor or as a similar concept to the processor, can be provided not only with specific hardware but also general hardware in which related software can be executed. When these functions are provided by the processor, the functions may be provided by a singular specific processor, a singular sharable processor, or plural processors in which sharing between the plural processors is possible. Also, usage of terms such as a processor, a control, or the like should not be construed as being limited to hardware capable of executing software but should be construed as indirectly including digital signal processor (DSP) hardware, read-only memory (ROM), random-access memory (RAM), and non- volatile memory used for storing software. Other well-known conventional hardware devices may be included.

[26] Hereinafter, the present invention will be described in detail by explaining exemplary embodiments of the invention with reference to the attached drawings. Detailed explanation will not be given when it is determined that detailed explanation about well- known function and configuration of the present invention may dilute the point of the present invention. The present invention will now be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

[27] FIG. 1 is a block diagram of a sensing data routing apparatus for a sensor node in a wireless sensor network according to an embodiment of the present invention. FIG. 2 is a flowchart illustrating a sensing data routing method performed by the routing apparatus of FIG. 1 according to an embodiment of the present invention.

[28] Referring to FIG. 1, the sensing data routing apparatus includes a route setup message receiving unit 110, a parent node selecting unit 120, and a sensing data transmitting unit 130.

[29] Referring to FIGS. 1 and 2, in operation S210, the route setup message receiving unit

110 receives route setup messages including residual energy information of one or more neighbouring sensor nodes within a wireless reception range of the sensor node from the neighbouring sensor nodes for a predefined reception waiting time. The route setup messages of the neighbouring sensor nodes respectively include addresses of each of the neighbouring sensor nodes and level of each of the neighbouring sensor nodes in a tree topology connecting the sensor nodes to a sink node which constitute the wireless sensor network.

[30] In operation S220, the parent node selecting unit 120 selects a parent node for routing from among the neighbouring sensor nodes based on the residual energy information of the neighbouring sensor nodes read from the route setup messages received from the route setup message receiving unit 110. The parent node selecting unit 120 selects a node with highest residual energy as a parent node from among the neighbouring sensor nodes, and a residual energy information storing unit (not shown) stores the residual energy information of each of the neighbouring sensor nodes.

[31] A level setting unit (not shown) sets a level of the sensor node based on a level of the parent node selected from among the neighbouring sensor nodes read from the route setup messages received from the route setup message receiving unit 110.

[32] Once the level setting unit sets the level of the sensor node, the route setup message receiving unit 110 no longer receives the route setup messages from the neighbouring sensor nodes in order to prevent a node of a lower level than the sensor node in the tree topology from being selected as a parent node.

[33] In operation S230, the sensing data transmitting unit 130 transmits the sensing data to the parent node selected by the parent node selecting unit 120. When the parent node successfully receives the transmitted sensing data, the parent node transmits a reception acknowledgement message including its own residual energy information.

[34] When the sensing data transmitting unit 130 is not received within a predefined reception waiting time the reception acknowledgement message indicating that the sensing data is successfully transmitted from the parent node, the sensing data transmitting unit 130 retransmits the sensing data within a preset maximum retransmission number of times.

[35] When the transmission of the sensing data to the parent node is failed, that is, when the reception acknowledgement message is not received from the parent node until the preset maximum retransmission number of times is reached, a new parent node is reselected from among neighbouring sensor nodes other than the parent node and the sensing data is transmitted to the selected new parent node. When the transmission of the sensing data to the parent node is failed, since a new parent node is selected from neighbouring sensor nodes other than the parent node and the sensing data is transmitted to the selected new parent node, data transmission reliability can be improved.

[36] A route setup message broadcasting unit (not shown) broadcasts a route setup message including residual energy information of the sensor node. Accordingly, other nodes whose level is not set yet in the tree topology receive the route setup message and respectively select their own parent nodes and set their own levels, thereby setting a data route through which their own sensing data is to be transmitted.

[37] A residual energy information updating unit (not shown) overhears reception acknowledgement messages including residual energy information of the sensor nodes from the neighbouring sensor nodes and updates the residual energy information of the neighbouring sensor nodes stored in the residual energy information storing unit. A parent node reselecting unit (not shown) reselects a new parent node when the residual energy information of the neighbouring sensor nodes updated by the residual energy information updating unit exceeds a threshold set by using the residual energy information of the parent node selected by the parent node selecting unit 120. Since path management is performed by using the overheard messages, additional processing costs can be reduced and energy efficiency can be improved.

[38] FIG. 3 is a flowchart illustrating a method of setting a path based on a tree topology connecting sensor nodes to a sink node in a wireless sensor network according to an embodiment of the present invention. FIG. 4 illustrates the wireless sensor network in which the method of FIG. 3 is performed according to an embodiment of the present invention.

[39] Referring to FIG. 3, in operation S301, the sink node which is a root node of the tree topology sets its own level to 0, and broadcasts a route setup message including its own address, its own level, and its own residual energy information.

[40] When a level of each of sensor nodes of the wireless sensor network is not set, in operation S302, each sensor node receives the route setup message broadcast in operation S301 for a predefined listen interval and the address, and stores the level, and the residual energy information of the sink node included in the received route setup message. A sensor node within a wireless transmission range of the sink node can receive the route setup message, and in this case, the sink node becomes a neighbouring sensor node within a wireless reception range of the sensor node.

[41] In operation S303, each sensor node selects a node with highest residual energy as its own parent node by using the information stored in operation S302, and stores other information in a candidate parent node table.

[42] In operation S304, each sensor node broadcasts a route setup message including its own address, its own level set to {parent level +1 }, and its own residual energy information.

[43] In operation S305, operations S302 through S304 are repeated until all the sensor nodes in the wireless sensor network respectively set their own levels. As a result, referring to FIG. 4, all the sensor nodes in the wireless sensor network are assigned their own levels to form a tree, parent nodes are selected on the basis of residual energy, and candidate parent node information is stored separately.

[44] FIG. 5 is a flowchart illustrating a method of transmitting data from each sensor node to a sink node in a wireless sensor network according to an embodiment of the present invention. FIG. 6 illustrates the wireless sensor network in which the method of FIG. 5 is performed according to an embodiment of the present invention.

[45] Referring to FIG. 5, in operation S501, a sensor node which generates sensing data or receives sensing data from another sensor node transmits a data message including its own address, a destination address set to its own parent address, and to-be-transmitted data to a parent node.

[46] In operation S502, the parent node which receives the data message from the sensor node transmits a reception acknowledgement message ACK including its own address, a destination address set to its own address, and its own residual energy to the sensor node.

[47] In operation S503, it is determined whether the reception acknowledgement message

ACK is received from the parent node within a predefined time. When it is determined in operation S503 that the reception acknowledgement message ACK is not received from the parent node within the predefined time, the method proceeds to operation S504. In operation S504, the sensor node retransmits the data message to the parent node within a preset maximum retransmission number of times and it is determined whether the preset maximum retransmission number of times is exceeded. When it is determined in operation S504 that the preset maximum retransmission number of times is exceeded, it is determined that the transmission of the date message to the parent node is failed and the method proceeds to operation S505. In operation S505, a node with highest residual energy is reselected as a new parent node from among candidate parent nodes. In operation S506, the data message is transmitted to the reselected new parent node.

[48] Referring to FIG. 6, when operations S501 through S507 are performed by each sensor node, sensing data is transmitted from a sensor node 9 generating the sensing data to a sink node 0.

[49] In this method, path management considering residual energy of each node is carried out as follows. A data message transmitted and received in a wireless environment is received by all nodes within a transmission range of a sender node. Path management is carried out by using such characteristics and acknowledgement messages.

[50] In other words, a receiver node to which the data message is transmitted from the sender node transmits reception acknowledgement messages including its own residual energy to the sender node. In this case, the nodes within the wireless transmission range of the sender node overhear the reception acknowledgement messages. Each of the nodes which receives the reception acknowledgement message determines whether the sender node transmitting the reception acknowledgement data message corresponds to any one of its own parent node and a candidate parent node. When it is determined that the sender node which transmits the reception acknowledgement data message corresponds to any one of its own parent node and candidate parent node, residual energy information of the node is updated with residual energy information of the sender node included in the reception acknowledgement data message. When the updated residual energy information exceeds a threshold d preset according to residual energy of a current parent node, the current parent node is updated with the sender node of the overheard reception acknowledgement message, and previous parent information is stored in candidate parent information.

[51] Referring to FIG. 6, data may be transmitted from a source node 9 to a sink node 0 through a path path_l, and updated information may be transmitted through a path path_2. As a result, since braided multi-path routing is achieved, energy consumption can be prevented from being concentrated on specific nodes.

[52] FIG. 7 illustrates a format of a route setup message according to an embodiment of the present invention.

[53] Referring to FIG. 7, the route setup message includes a header 701, a source address field 702, a destination address field 703, a level field 704, and a residual energy information field 705.

[54] The header 701 includes information regarding the type of a message. The source address field 702 includes address information of a node which transmits the message. A destination address included in the destination address field 703 is set to a broadcast address. The level field 704 and the residual energy information field 705 respectively include a level and residual energy information of the node which transmits the message.

[55] FIG. 8 illustrates a format of a reception acknowledgement message according to an embodiment of the present invention.

[56] Referring to FIG. 8, the reception acknowledgement message includes a header 801, a source address field 802, a destination address field 803, and a residual energy information field 804.

[57] The header 801 includes information regarding the type of a data message. The source address field 802 includes address information of a node which receives the data message. The destination address field 803 includes address information of a node which transmits the data message.

[58] The residual energy information field 804 includes residual energy information of the node which receives the data message, such that routing path management can be performed on the basis of the energy remnant information included in a reception acknowledgment message without a necessity for a node which overhears the reception acknowledgment message to receive another message including the energy remnant information.

[59] FIG. 9 illustrates a format of a data message according to an embodiment of the present invention.

[60] Referring to FIG. 9, the data message includes a header 901, a source address field

902, a destination address field 903, and a data field 904.

[61] The header 901 includes information regarding the type of a data message. The source address field 902 includes address information of a node which receives the data message. A destination address included in the destination address field 903 becomes an address of a parent node of a sensor node which transmits the data message.

[62] FIGS. 1OA through 1OD is a flowchart illustrating a method of receiving a message of a sensor node according to an embodiment of the present invention including operations SlOI l through S 1015 of receiving and processing the route setup message of FIG. 7, operations S 1021 through S 1025 of receiving and processing the reception acknowledgement message of FIG. 8, and operations S 1031 through S 1032 of receiving and processing the data message of FIG. 9.

[63] Referring to FIG. 1OA, a sensor node receives a message in operation SlOOl, and determines the kind of the message by using a header of the message in operation SlOlO, S1020, and S1030.

[64] In operation SlOlO, it is determined whether the message is a route setup message.

When it is determined in operation SlOlO that the message is the route setup message, the method proceeds to operation SlOI l. Referring to FIG. 1OB, in operation SlOl 1, it is determined whether a destination address is set to a broadcast address. When it is determined in operation SlOl 1 that the destination address is set to the broadcast address, the method proceeds to operation S 1012. In operation S 1012, an address, a level, and residual energy information of a sender node included in the route setup message is stored. In operation S 1013, it is determined whether a predefined reception waiting time has expired. When it is determined in operation S 1013 that the predefined reception waiting time has expired, the method proceeds to operation S 1014. In operation S1014, the route setup message is no longer received, a parent node is selected, and a candidate parent node table is generated. In operation S 1015, the sensor node broadcasts a route setup message including its own address, its own level, and its own residual energy information.

[65] When it is determined in operation SlOlO that the message is not the route setup message, the method proceeds to operation S 1020. In operation S 1020, it is determined whether the message is a reception acknowledgement message. When it is determined in operation S 1020 that the message is the reception acknowledgement message, the method proceeds to operation S1021. Referring to FIG. 1OC, in operation S1021, it is determined whether a destination address is its own address. When it is determined in operation S1021 that the destination address is its own address, the method proceeds to operation S 1022. In operation S 1022, it is checked that the sensor node has successfully transmitted a data message. When it is determined in operation S 1021 that the destination address is not its own address, the method proceeds to operation S 1023. In operation S 1023, it is determined whether the destination address is a parent address or a candidate parent address. When it is determined in operation S 1023 that the destination address is the parent address or the candidate parent address, the method proceeds to operation S 1024. In operation S 1024, residual energy information of the parent node or the candidate parent node is modified. In operation S 1025, the parent node and the candidate parent node are updated according to the modified residual energy information.

[66] When it is determined in operation S 1020 that the message is not the reception acknowledgement message, the method proceeds to operation S 1030. In operation S 1030, it is determined whether the message is a data message. When it is determined in operation S 1030 that the message is the data message, the method proceeds to operation S 1031. Referring to FIG. 1OC, in operation S 1031, it is determined whether a destination address is its own address. When it is determined in operation S 1031 that the destination address is its own address, the method proceeds to operation S 1032. In operation S 1032, the data message is transmitted to a parent node.

[67] FIG. 11 is a flowchart illustrating a method of transmitting a data message of a sensor node according to an embodiment of the present invention, including operations of transmitting the data message of FIG. 9 to a parent node and operations of re- selecting a parent node from among candidate parent nodes and transmitting the data message to the reselected parent node when the transmission of the data message to the parent node is failed.

[68] FIG. 11 is a detailed flowchart illustrating the method of FIG. 5. Accordingly, a repeated explanation of the same operations as those of the method of FIG. 5 will not be given.

[69] In operation Sl 101, a sensor node generates sensing data or receives sensing data in the form of a data message from another sensor node. In operation Sl 102, the sensor node transmits the data message to its own parent node. In operation Sl 103, a reception acknowledgement message from the parent node is waited for a predefined reception waiting time and it is determined whether the predefined reception waiting time has expired. When it is determined in operation Sl 103 that the predefined reception waiting time has expired, the method proceeds to operation Sl 104. In operation Sl 104, it is determined whether a reception acknowledgement message is received. When it is determined in operation Sl 104 that the reception acknowledgment message is not received, the method proceeds to operation Sl 105. In operation Sl 105, the data message is retransmitted within a predetermined maximum retransmission number of times and it is determined whether the predetermined maximum retransmission number of times is exceeded. When it is determined in operation Sl 105 that the predetermined maximum retransmission number of times is exceeded, the method proceeds to operation Sl 106. In operation Sl 106, it is determined whether a candidate parent node table is empty. When it is determined in operation Sl 106 that the candidate parent node table is not empty, the method proceeds to operation Sl 107. In operation Sl 107, a parent node is reselected from among candidate parent nodes and information of the parent node is updated with the new parent node.

[70] The present invention can be embodied as computer-readable codes on a computer- readable recording medium. The computer-readable recording medium is any data storage device that can store data that can be thereafter read by a computer system, read-only memory (ROM), random-access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and carrier waves (such as data transmission through the Internet). The computer-readable recording medium can also be distributed over network coupled computer systems so that the computer-readable code is stored and executed in a distributed fashion. A font ROM data structure according to the present invention can also be embodied as computer-readable codes on a computer-readable recording medium such as ROM, RAM, CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and carrier waves.

Claims

[1] L A sensing data routing apparatus for a sensor node in a wireless sensor network consisting of a sink node and one or more sensor nodes, the routing apparatus comprising: a route setup message receiving unit receiving route setup messages including residual energy information of each of one or more neighboring sensor nodes within a wireless reception range of the sensor node from the neighboring sensor nodes for a predefined reception waiting time; a parent node selecting unit selecting a parent node for routing from among the neighboring sensor nodes based on the residual energy information of each of the neighboring sensor nodes; and a sensing data transmitting unit transmitting the sensing data to the selected parent node.

[2] 2. The sensing data routing apparatus of claim 1, wherein the sensing data transmitting unit reselects a parent node from among neighboring sensor nodes other than the selected parent node and transmits the sensing data to the reselected parent node when the transmission of the sensing data to the selected parent node is failed.

[3] 3. The sensing data routing apparatus of claim 1, wherein the parent node selecting unit selects a node with highest residual energy as a parent node from among the neighboring sensor nodes.

[4] 4. The sensing data routing apparatus of claim 1, further comprising a route setup message broadcasting unit broadcasting a route setup message including residual energy information of the sensor node.

[5] 5. The sensing data routing apparatus of claim 1, wherein the parent node transmits a reception acknowledgement message including residual energy information of the parent node when the transmitted sensing data is successfully received.

[6] 6. The sensing data routing apparatus of claim 1, wherein the sensing data transmitting unit retransmits the sensing data within a preset maximum retransmission number of times when a reception acknowledgement message indicating that the transmission of the sensing data is succeeded is not received from the parent node within a predefined reception waiting time.

[7] 7. The sensing data routing apparatus of claim 1, further comprising a residual energy information storing unit storing the residual energy information of the neighboring sensor nodes from the received route setup messages.

[8] 8. The sensing data routing apparatus of claim 7, further comprising a residual energy information updating unit overhearing a reception acknowledgement message including the residual energy information of each of the neighboring sensor nodes from the neighboring sensor nodes and updating the stored residual energy information of the neighboring sensor nodes.

[9] 9. The sensing data routing apparatus of claim 8, further comprising a parent node reselecting unit reselecting a parent node when the updated residual energy information of the neighboring sensor nodes exceeds a threshold set by using residual energy information of the parent node.

[10] 10. The sensing data routing apparatus of claim 1, wherein the route setup messages respectively include level of each of the neighboring sensor nodes in a tree topology connecting the one or more sensor nodes to the sink node in the wireless sensor network.

[11] 11. The sensing data routing apparatus of claim 10, further comprising a level setting unit setting a level of the sensor node based on a level of the selected parent node from among the levels of the neighboring sensor nodes.

[12] 12. The sensing data routing apparatus of claim 11, wherein the route setup message receiving unit no longer receives the route setup messages from the neighboring sensor nodes after the level setting unit sets the level of the sensor node.

[13] 13. A sensing data routing method for a sensor node in a wireless sensor network consisting of a sink node and one or more sensor nodes, the routing method comprising: receiving route setup messages including residual energy information of each of one or more neighboring sensor nodes within a wireless reception range of the sensor node from the neighboring sensor nodes for a predefined reception waiting time; selecting a parent node for routing from among the neighboring sensor nodes based on the residual energy information of each of the neighboring sensor nodes; and transmitting the sensing data to the selected parent node.

[14] 14. The sensing data routing method of claim 13, wherein the transmitting of the sensing data comprises reselecting a parent node from among neighboring sensor nodes other than the selected parent node and transmitting the sensing data to the reselected parent node when the transmission of the sensing data to the parent node is failed.

[15] 15. The sensing data routing method of claim 13, wherein the selecting of the parent node comprises selecting a node with highest residual energy as a parent node from among the neighboring sensor nodes.

[16] 16. The sensing data routing method of claim 13, further comprising broadcasting a route setup message including residual energy information of the sensor node.

[17] 17. The sensing data routing method of claim 13, wherein the parent node transmits a reception acknowledgement message including residual energy information of the parent node when the transmitted sensing data is successfully received.

[18] 18. The sensing data routing method of claim 13, wherein the transmitting of the sensing data further comprises retransmitting the sensing data within a preset maximum retransmission number of times when a reception acknowledgement message indicating that the transmission of the sensing data is succeeded is not received from the parent node within a predefined reception waiting time.

[19] 19. The sensing data routing method of claim 13, further comprising storing the residual energy information of the neighboring sensor nodes from the received route setup messages.

[20] 20. The sensing data routing method of claim 19, further comprising overhearing a reception acknowledgement message including the residual energy information of each of the neighboring sensor nodes from the neighboring sensor nodes and updating the stored residual energy information of the neighboring sensor nodes.

[21] 21. The sensing data routing method of claim 20, further comprising reselecting a parent node when the updated residual energy information of the neighboring sensor nodes exceeds a threshold set by using residual energy information of the parent node.

[22] 22. The sensing data routing method of claim 13, wherein the route setup messages respectively include levels of the neighboring sensor nodes in a tree topology connecting the one or more sensor nodes to the sink node in the wireless sensor network.

[23] 23. The sensing data routing method of claim 22, further comprising setting a level of the sensor node based on a level of the selected parent node from among the levels of the neighboring sensor nodes.

[24] 24. The sensing data routing method of claim 23, further comprising not receiving the route setup messages from the neighboring sensor nodes after the level of the sensor node is set.