KR101166108B1 - Location based service system and method for cognizing loation thereof - Google Patents

Abstract

The present invention relates to a location recognition system. The location recognition system of the present invention receives a location recognition message for positioning from each of the fixed nodes and the fixed nodes having location information on a unit space, and among the received beacon messages, the location recognition message having the largest signal strength is received. The mobile node selects the fixed node that has been transmitted, and the unit node of the fixed node selected by the mobile node is managed as the location of the mobile node through the location table. And a location-aware server for checking the location of the mobile station and sending a message through the fixed node of the unit area where the mobile node is located.

Description

Location recognition system and its location recognition method {LOCATION BASED SERVICE SYSTEM AND METHOD FOR COGNIZING LOATION THEREOF}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a location recognition system, and more particularly, to a location recognition system having a reduced amount of computation for location recognition and a location recognition method thereof.

One of the common methods used for location recognition in a location recognition system is triangulation. Trigonometry is a method of measuring position by receiving signals from multiple (usually three) base stations. As an example of trigonometry, a time of arrival measurement (TOA) method, a signal arrival time measurement (TDOA) method, and an angle of arrival measurement (Angle Of Arrival, hereinafter referred to as 'AOA').

The TOA method is a method of measuring the position of a mobile node using a signal arrival time with signals received at two other fixed nodes from a fixed node that receives the signal of the mobile node. The TDOA method recognizes the position of a mobile node by using a difference between a signal of a fixed node including a mobile node and a signal arrival time from adjacent fixed nodes. In addition, the AOA method is a method of recognizing the position of the mobile node by measuring the angle of arrival of the radio wave received by the mobile node at the fixed node.

The above-described location recognition methods are techniques for increasing the accuracy of location recognition of the mobile node. The mobile node or fixed node processes the received signals from the plurality of base stations for location recognition of the mobile node.

These location recognition methods have a problem in that an operation amount for location recognition is increased in a mobile node or a fixed node by performing a complex operation for location recognition. In addition, as the number of mobile nodes on the network increases, the amount of computation for location recognition increases, thereby degrading the overall performance of the location recognition system.

SUMMARY OF THE INVENTION An object of the present invention is to provide a location recognition system and a location recognition method thereof in which the amount of calculation for location recognition is reduced.

Another object of the present invention is to provide a location recognition system and a location recognition method in which system performance is not degraded in a network in which a plurality of mobile nodes exist.

The position recognition system of the present invention receives fixed nodes having position information on a unit space, a position recognition message for positioning from each of the fixed nodes, and the position recognition having the largest signal strength among the received beacon messages. A mobile node for selecting a fixed node that has sent a message, and a unit space of the fixed node selected by the mobile node as a location of the mobile node through a location table, and if there is a message to send to the mobile node, the location table And a location recognition server for identifying a location of the mobile node by searching for and transmitting a message through a fixed node of a unit area in which the mobile node is located.

In this embodiment, the location aware message is a beacon message message.

In this embodiment, the mobile node transmits the information of the selected fixed node to the location aware server through the selected fixed node.

In this embodiment, when the fixed nodes receive the location recognition request message requesting the location aware message from the mobile node, the fixed nodes include the signal strength measured from the location awareness request message in the location aware message and transmit the received signal.

In this embodiment, if the difference between the signal strength of the location-aware request message and the signal strength of the location-aware message exceeds a preset threshold, the mobile node removes a signal distortion component included between the corresponding signal strengths. do.

In this embodiment, each of the signal strength of the location awareness request message and the signal strength of the location awareness message includes at least one of a link quality indicator and a received signal strength indicator.

In this embodiment, the mobile node selects a fixed node having the largest signal strength through an average of the signal strength of the location awareness request message and the signal strength of the location awareness message.

In this embodiment, when the mobile node senses at least one of an operation of the mobile node and an external interrupt, the mobile node operates in a wake-up mode.

In this embodiment, the fixed node includes a message generator for generating a location aware message, and a message transceiver for transmitting the location aware message.

In this embodiment, the mobile node receives a location-aware messages from the fixed nodes, the transceiver for transmitting a node selection message including the selected fixed node information, the signal strength for measuring the signal strength of the location-aware message A measuring unit, a node selecting unit for selecting a fixed node that has transmitted the location recognition message having the largest signal strength, and a message generating unit generating the node selection message based on the selected fixed node.

In this embodiment, the fixed node receives a location recognition request message, a message transceiver for transmitting a location recognition message corresponding to the location recognition request message, signal strength measurement for measuring the signal strength of the location recognition request message And a message generator for generating a location recognition message including the measured signal strength.

In this embodiment, the mobile node receives a location-aware messages from the fixed nodes, the transceiver for transmitting a node selection message including the selected fixed node information, the signal strength for measuring the signal strength of the location-aware message A node selector configured to select a base station having the largest average signal strength obtained through an average of the measured signal strength and the signal strength measured by the fixed node, and the node selection message based on the selected fixed node It includes a message generating unit for generating a.

The method of location recognition according to the present invention comprises the steps of measuring the signal strength of location awareness messages received from fixed nodes at a mobile node, selecting a fixed node having the largest signal strength among the measured signal strengths at the mobile node, Providing, by the selected fixed node, information about a mobile node located within a unit area of the fixed node to a location recognition server, and if there is a message to be transmitted from the location recognition server to the mobile node, the fixed node where the mobile node is located. Searching for and transmitting a message from the location aware server to the mobile node via the searched fixed node.

In this embodiment, the location aware message is a beacon message.

The location recognition method of the present invention comprises the steps of: transmitting a location awareness request message from the mobile node to the fixed nodes, measuring signal strength of the location awareness request message from the fixed node, from each of the fixed nodes to the mobile node; Transmitting a location aware message including the signal strength, measuring signal strength of the location aware messages received from the fixed nodes at the mobile node, by the signal strength measured at the mobile node and by the fixed node Selecting a fixed node having the largest average signal strength through an average of the measured signal strengths, providing information on a mobile node located within a unit area of the fixed node to the location recognition server at the selected fixed node; If there is a message to be sent from the location aware server to the mobile node, Step of searching for the fixed node is the same node is located, and through the fixed node the search in the location detection server transmitting the message to the mobile node.

In this embodiment, the location aware message is a beacon message.

In this embodiment, selecting the fixed node having the largest average signal strength exceeds the preset threshold between the signal strength measured by the mobile node and the signal strength measured by the fixed node. Removing a signal distortion component included between the corresponding signal strengths included in the step; and selecting a fixed node having the largest average signal strength based on the average signal strength from which the signal distortion component is removed.

In this embodiment, each of the signal strength measured by the mobile node and the signal strength measured by the fixed node includes at least one of a link quality indicator and a received signal strength indicator.

The mobile node of the present invention receives location recognition messages from fixed nodes, a transceiver for transmitting a node selection message including selected fixed node information, a signal strength measuring unit for measuring signal strength of the location recognition message, and the measured signal A node selector for selecting a fixed node that has transmitted the location recognition message having the largest average signal strength using at least one of the strength and the signal strength measured by each of the fixed nodes, and a location in a unit space of the selected fixed node And a message generator for generating a node selection message for transmitting the location information.

A method of location recognition of a mobile node of the present invention comprises the steps of receiving location awareness messages from fixed nodes, measuring signal strength of each of the location awareness messages, measured signal strength and signals measured at each of the fixed nodes, respectively. Selecting a fixed node that has transmitted the location-aware message having the largest average of signal strength using at least one of the strengths, and transmitting the location information located in the unit space of the selected fixed node to the location-aware server through the fixed node. Sending a node selection message for the purpose of transmission.

According to the present invention, the amount of calculation for the position recognition at the mobile node or the fixed node can be reduced by performing the position recognition based on the signal strength measured at the mobile node or the fixed node. In addition, as the amount of computation for location recognition is reduced, even if the number of mobile nodes in the network is increased, system performance may not be degraded.

1 is a view showing a position recognition system according to the present invention,
2 is a diagram illustrating an example of a fixed node shown in FIG. 1;
3 is a diagram illustrating an example of a mobile node shown in FIG. 1;
4 is a signal flowchart showing a position recognition operation according to the first embodiment of the present invention;
5 is a graph illustrating signal strength of a beacon message received by a mobile node according to an embodiment of the present invention;
6A and 6B are signal flow diagrams illustrating a position recognition operation according to a second embodiment of the present invention;
7 is a graph illustrating signal distortions included in a signal strength measured for position recognition according to a second embodiment of the present invention;
8 is a graph in which signal distortion is removed from signal strength measured for position recognition in a position recognition operation according to a second embodiment of the present invention;
9 is a flowchart illustrating message transmission between a mobile node and a server according to an embodiment of the present invention;
10 is a view showing a location table of the location recognition server shown in FIG. 1;
11 is a view illustrating a location recognition cycle according to transmission and reception of a location recognition message between a fixed node and a mobile node according to an embodiment of the present invention;
12 is a view for explaining an example of applying a location recognition system according to an embodiment of the present invention in a school classroom,
13 is a flowchart illustrating an example in which a location recognition system according to an embodiment of the present invention is applied to access control;
14A and 14B are flowcharts illustrating an example of applying a location recognition system to classroom attendance management according to an embodiment of the present invention;
15A and 15B are flowcharts illustrating an example of applying a location recognition system according to an embodiment of the present invention to a viewing facility reservation; and
16 is a flowchart illustrating an operation of reserving a viewing facility of a mobile node according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and how to accomplish it, will be described with reference to the embodiments described in detail below with reference to the accompanying drawings. However, the present invention is not limited to the embodiments described herein but may be embodied in other forms. The embodiments are provided so that those skilled in the art can easily carry out the technical idea of the present invention to those skilled in the art.

In the drawings, embodiments of the present invention are not limited to the specific forms shown and are exaggerated for clarity. In addition, parts denoted by the same reference numerals throughout the specification represent the same components.

The present invention provides a location recognition system and a location recognition method thereof having a reduced amount of computation for location recognition. The location recognition system of the present invention can be applied to a communication system including a fixed node and a mobile node, such as a mobile communication network system, a sensor network system, a radio frequency identification (RFID) system, and the like.

The fixed node of the present invention is a node that is installed at a fixed position, and includes, for example, a base station, a repeater, an access point, and the like. In addition, a mobile node is a node having mobility, and includes, for example, a terminal. Here, the terminal includes, for example, all user devices capable of communicating with fixed nodes such as mobile phones, laptops, and netbooks.

1 is a view showing a position recognition system according to the present invention.

Referring to FIG. 1, a location aware system includes a location aware server 10, fixed nodes 20 and 30, and a mobile node 40.

The location aware server 10 is a server 10 that manages the location of the mobile node 40 recognized through fixed nodes.

The fixed nodes 20, 30 communicate with the location aware server 10 in a wired or wireless manner. The fixed nodes 20, 30 may communicate in a wireless manner with a plurality of mobile nodes (eg, mobile node 40). In this case, the first fixed node 20 has a first unit space 25, and the second fixed node 30 has a second unit space 35. Here, each of the unit spaces 25 and 35 is a logical space or a physical space separated to recognize the location of the mobile node 40. For example, the unit space may be a space, such as a department, a classroom, a hospital room, which are separated by walls in an office, a school, a hospital, or the like. In addition, the open space is a space included within a predetermined distance centered on the fixed node.

The mobile node 40 is mobile and can communicate with the fixed nodes 20, 30. The mobile node 40 may provide the location information of the mobile node 40 to the location recognition server 10 through one of the fixed nodes 20, 30.

Next, the positioning operation of the mobile node in the position recognition system of the present invention is as follows.

The fixed nodes 20 and 30 may generate a location awareness message for location recognition and transmit the generated location awareness message to the mobile node 40. The fixed nodes 20 and 30 transmit location recognition messages at predetermined intervals. In addition, the fixed nodes 20, 30 may transmit the location awareness message by receiving a location awareness request message requesting the transmission of the location awareness message from the mobile node 40.

For example, fixed nodes 20 and 30 and mobile node 40 are, for example, Institute of Electrical and Electronics Engineers (hereinafter referred to as "IEEE") 802.15, IEEE 802.11, IEEE 802.16 Can communicate with each other based on the standard, such as. Thus, the location aware message is, for example, a beacon message.

Location recognition of the mobile node 40 can be distinguished in two ways, for example. There may be a method of using only the signal strength measured at the mobile node and a method of using both the signal strength measured at the mobile node and the fixed node.

First, the mobile node 40 may receive a location awareness message for location recognition from the fixed nodes 20, 30.

Upon receiving the location awareness message from the fixed nodes 20, 30, the mobile node 40 measures the signal strength of each of the location awareness messages. The mobile node 40 selects a fixed node (eg, the fixed node 20) that has transmitted the location awareness message having the largest signal strength among the location awareness messages. The mobile node 40 transmits a node selection message for location recognition to the selected fixed node 20.

The fixed node 20 recognizes the mobile node 40 located in the unit space 20 of the fixed node 20 according to the reception of the node selection message. The fixed node 20 provides the location recognition server 10 with information about the mobile node 40 located in the unit space of the fixed node.

Secondly, the mobile node 40 receives the location awareness message by sending a location awareness request message to the fixed nodes 20, 30.

The fixed nodes 20 and 30 measure the signal strength of the location awareness request message. The fixed nodes 20 and 30 may transmit a location awareness message including the signal strength information measured by the mobile node 40.

Upon receiving the location awareness message from the fixed nodes 20, 30, the mobile node 40 measures the signal strength of each of the location awareness messages. In addition, the mobile node 40 selects a fixed node having the largest signal strength (eg, the fixed node 20) based on the measured signal strength and the signal strength included in the location recognition message. The mobile node 40 transmits a node selection message for location recognition to the selected fixed node 20.

If there are a plurality of fixed nodes having the largest signal strength among the signal strengths measured by the mobile node 40, the mobile node 40 selects a fixed node which is set in advance according to a priority or the like.

The fixed node 20 recognizes the mobile node 40 located in the unit space 20 of the fixed node 20 according to the reception of the node selection message. The fixed node 20 provides the location recognition server 10 with information about the mobile node 40 located in the unit space of the fixed node.

The location recognition server 10 may manage the mobile node 40 located in the unit area of the fixed node 20. The location recognition server 10 may manage location information of the mobile node 40 through a location recognition table.

If there is a request for providing location information of the mobile node 40, the location recognition server 10 may provide location information of the mobile node in response to the request for providing the location information.

Meanwhile, signal strengths measured by the fixed nodes 20 and 30 and the mobile node 40 of the present invention are, for example, a link quality indicator (LQI) and a received signal strength indicator (RSSI). ), A signal-to-interference noise ratio (SINR), a signal-to-noise ratio (SNR), and the like.

As described above, the mobile node of the present invention uses the signal strength of the signal received at the mobile node for location recognition, or uses the signal strengths received at each of the mobile node and the fixed node.

The mobile node of the present invention recognizes the position of the mobile node by selecting a fixed node having excellent signal strength characteristics, and thus can recognize the position of the mobile node without performing a complicated operation. According to the present invention, the amount of calculation for position recognition is conventional trigonometry (e.g., time of arrival (TOA), signal arrival time (TDOA), and angle of arrival (AOA). Angle of Arrival), etc.), the location recognition performance does not deteriorate even if the number of mobile nodes increases on the network.

FIG. 2 is a diagram illustrating a first fixed node illustrated in FIG. 1.

Referring to FIG. 2, the first fixed node 20 includes a message generator 21, a transceiver 22, and a signal strength measurer 23.

The message generator 21 generates a location recognition message and a location information message.

The location awareness message is a message used for mobile node 40 to select a fixed node for location recognition. The location aware message, for example, includes a beacon message. The location awareness message may include identifier information of the first fixed node 20 so that the mobile node 40 identifies the first fixed node 20. The location recognition message may include the signal strength when the signal strength is provided from the signal strength measuring unit 23.

The location information message is a message for providing location information of the mobile node 40 to the location recognition server 10 according to the selection from the mobile node 40. The location information message may indicate that the mobile node 40 exists in the unit space of the first fixed node 20. Accordingly, the location information message may be generated in response to the node selection message sent by the mobile node 40 by the selection of the fixed node 20.

The message generator 21 outputs a location recognition message or a location information message to the transceiver 22.

The transceiver 22 may communicate with the location recognition server 10 or the mobile node 40 in a wired and / or wireless manner. For example, the transmitter / receiver 22 transmits the location recognition message generated by the message generator to the mobile node 40.

When the transceiver 22 receives the node selection message from the mobile node 40 by the selection of the first fixed node 20, the transceiver 22 outputs the received node selection message to the message generator 21. The transceiver 22 transmits a location information message corresponding to the node selection message to the location recognition server 10.

When the transceiver 22 receives the location recognition request message from the mobile node 40, the transceiver 22 may output the location recognition request message to the message generator 21 or the signal strength measurer 23. The location recognition request message is a message for requesting transmission of a location awareness message. The location aware message is a message sent by the mobile node 40.

When the signal strength measuring unit 23 receives the location recognition request message, the signal strength measuring unit 23 measures the signal strength of the location recognition request message. The signal strength measuring unit 23 outputs the measured signal strength to the message generator 21. The signal strength measuring unit 23 may not be included in the first fixed node 20 unless the signal strength measurement of the location recognition request message is performed.

As an example, the first fixed node 20 has been described as a reference, but the remaining fixed nodes may have a structure similar to that of the first fixed node 20.

FIG. 3 is a diagram illustrating an example of the mobile node shown in FIG. 1.

Referring to FIG. 3, the mobile node 40 includes a node state manager 41, a message generator 42, a transceiver 43, a signal strength measurer 44, and a node selector 45. .

The node state manager 41 manages the operation state of the mobile node 40. The node state manager 41 manages state transitions between an idle mode (or a sleep mode (standby state) mode and a wake-up mode. The idle mode is a mode for deactivating the operation of the mobile node 40 to prevent power consumption, and the wake-up mode is a mode for activating the operation of the mobile node 40. The node state manager 40 may activate an operation of some modules required for the operation of the mobile node 40 even in the idle mode.

The node state manager 41 may include a sensor, for example, an acceleration sensor, an inclination sensor, a magnetic sensor (or a magnetic switch), and the like.

For example, the node state manager 41 including the acceleration sensor may receive a sensor value (change value of acceleration) according to the movement of the mobile node 40 from the acceleration sensor. The node state manager 41 including the inclination sensor may receive a sensor value (change value of tilt) according to the movement of the mobile node 40 from the inclination sensor. In addition, the node state management unit 41 including the magnetic sensor may receive a sensor value (magnetic interrupt signal) applied from the outside from the magnetic sensor.

At this time, when the node state manager 41 detects a sensor value exceeding a preset threshold value (such as an operation or interrupt signal of the mobile node), the node state manager 41 activates the mobile node 40 in the idle mode to enter the wake-up mode. Make the switch.

Meanwhile, the node state manager 41 may control the location recognition operation cycle of the mobile node 40. For example, the node state manager 41 including the acceleration sensor may reduce the period of the location recognition operation when measuring the sensor value related to the increase of the speed of the mobile node 40. When the node state manager 41 measures a sensor value related to the speed reduction of the mobile node 40, the node state manager 41 may reduce the location recognition operation cycle. As such, the node state manager 41 may actively control the location recognition operation cycle of the mobile node 40.

When a sensor value exceeding the threshold is generated, the node state manager 41 may control the message generator 42 or the transceiver 43 to perform the location recognition operation according to the transition to the active state.

The message generator 42 may generate a location recognition request message to receive a location aware message (eg, a beacon message) from the fixed nodes 20 and 30.

In addition, when the message generator 45 receives the information of the fixed node selected by the node selector 45, the message generator 45 generates a node selection message including the information of the selected fixed node. The node selection message is a message for notifying that the mobile node 40 exists in the unit space of the selected first fixed node 20.

The message generator 42 outputs the location recognition request message or the node selection message to the transceiver.

The transceiver 42 may receive a location recognition message. In this case, the transceiver 42 may receive the location recognition message without transmitting the location recognition request message.

Alternatively, the transceiver 42 may transmit a location recognition request message to the fixed nodes 20 and 30 and then receive a location recognition message corresponding to the location recognition request message.

When receiving the location recognition message, the transceiver 42 outputs the location awareness message to the signal strength measurement unit 44. In addition, the transmitter / receiver 42 may output information on the signal strength received to the node selector 45 when the location recognition message includes the signal strength measured at the fixed node.

The transmission / reception unit 42 transmits a node selection message generated by the selection of the first fixed node 20 to the selected first fixed node 20, for example, in the message generator 42.

The signal strength measuring unit 44 measures the signal strength according to the reception of the location recognition message. When the signal strength measuring unit 44 receives the location recognition messages from the fixed nodes 20 and 30, respectively, the signal strength measuring unit 44 measures the signal strength for each location recognition message. The signal strength measuring unit 44 outputs the measured signal strength to the node selector 45.

The node selector 45 selects a fixed node having the largest signal strength among the signal strengths received from the signal strength measurer 44. As such, the first method of selecting the fixed node according to the reception of the signal strength by the signal strength measuring unit 44 is shown in Equation 1 below.

는 제 i 고정 노드에서 송신한 위치 인식 메시지이다. SignalStrengh는 신호 세기 연산이다.

는 복수개의 위치 인식 메시지에 대한 신호 세기 평균 연산이다. MAX는 최대값을 선택하는 연산을 나타낸다.here,

Is the location awareness message sent by the i-th fixed node. SignalStrengh is a signal strength operation.

Is a signal strength average operation for a plurality of location-aware messages. MAX represents the operation of selecting the maximum value.

In addition, when the node selector 45 receives the signal strength measured at the fixed nodes from the transceiver 43, the node selector 45 has the largest signal strength through an average with the signal strength received from the signal strength measurer 44. The first fixed node 20 may be selected. That is, for one fixed node, the node selector 45 may select the fixed node through an average of the signal strength measured by the mobile node and the signal strength measured by the fixed node. As such, the second method of selecting the fixed node according to the reception of the signal strength by the signal strength measuring unit 44 is shown in Equation 2 below.

는 제 i 고정 노드에서 송신한 위치 인식 메시지이다.

는 제 i 고정 노드에서 이동 노드(40)로부터 수신한 위치 인식 요청 메시지이다. 측정한 SignalStrengh는 신호 세기 연산이다.

는 복수개의 위치 인식 메시지에 대한 신호 세기 평균 연산이다. MAX는 최대값을 선택하는 연산을 나타낸다.here,

Is the location awareness message sent by the i-th fixed node.

Is a location-aware request message received from the mobile node 40 at the i-th fixed node. Measured SignalStrengh is a signal strength calculation.

Is a signal strength average operation for a plurality of location-aware messages. MAX represents the operation of selecting the maximum value.

In the second method, when the difference between the signal strength measured by the mobile node and the signal strength measured by the fixed node is greater than or equal to a preset threshold, it may be confirmed that signal distortion has occurred. In this case, the node selector 45 may remove signal distortion through a filter (not shown) included therein.

The node selector 45 outputs the information about the selected first fixed node 20 to the message generator 42.

As described above, the mobile station 40 may determine the first unit space 25 of the selected first fixed node 20 as the location of the mobile node through the selection of the first fixed node 20 based on the received signal strength. have.

4 is a signal flowchart showing a position recognition operation according to the first embodiment of the present invention.

Referring to FIG. 4, the location aware system includes a location aware server 10, fixed nodes 20 and 30, and a mobile node 40.

The mobile node 40 may operate in an idle mode and may be switched to a wake-up mode through a sensor included therein (step 110). In the wake-up mode, the mobile node 40 may perform a location recognition operation.

The mobile node 40 may receive a plurality of beacon messages (ie, location aware messages) from the fixed nodes 20, 30, respectively.

The first fixed node 20 may transmit a first beacon message, a third beacon message, a fifth beacon message, and a seventh beacon message to the mobile node 40 (steps 111, 113, 115, And step 117). Each of the beacon messages (first beacon message, third beacon message, fifth beacon message, and seventh beacon message) of the first fixed node 20 may be transmitted at a predetermined period.

The second fixed node 30 may transmit a second beacon message, a fourth beacon message, a sixth beacon message, and an eighth beacon message to the mobile node 40 (step 112, 114, 116, Step 118). Each of the beacon messages (second beacon message, fourth beacon message, sixth beacon message, and eighth beacon message) of the second fixed node 30 may be transmitted at intervals of a preset period.

As an example, steps 111 through 118 described the case where four fixed beacon messages are transmitted from each of the fixed nodes 20 and 30, but the fixed nodes 20 and 30 may transmit at least one beacon message. . To distinguish beacon messages of each fixed node 20, 30, each beacon message may include fixed node identifier information.

The mobile node 40 measures signal strength of beacon messages received from the fixed nodes 20 and 30 (step 119).

The mobile node selects a fixed node having the largest signal strength (step 120). For example, when the first fixed node 20 is selected, the mobile node 40 generates a node selection message to transmit to the selected first fixed node 20. That is, the mobile node 40 is located in the first unit space 25 of the first fixed node 20. The node selection message may include identifier information of the mobile node 40 or identifier information of the first fixed node 20.

The mobile node 40 transmits a node selection message to the selected first fixed node 20 (step 121). The first fixed node 20 generates a location information message. The location information message indicates that the mobile node 40 is located in the first unit space 25 of the first fixed node 20. The location information message may include an identifier of the fixed node 20 and an identifier of the mobile node 40 included in the unit area of the first fixed node 20.

The first fixed node 20 transmits a location information message to the location recognition server 10 (step 122). The location recognition server 10 may identify the location of the mobile node 40 in the first unit space 25 of the first fixed node 20 according to the location information message.

The location recognition server 10 stores and manages the location of the mobile node 40 (step 123). Subsequently, if the location recognition server 10 is requested to provide the information on the location of the mobile node 40 from the mobile node 40 or an administrator device (not shown) that manages the mobile node, the location of the mobile node 40 is determined. Location information can be provided.

5 is a graph illustrating signal strength of a beacon message received by a mobile node according to an embodiment of the present invention.

Referring to FIG. 5, the horizontal axis represents time and the vertical axis represents signal strength, for example, a link quality indicator (LQI). As an example, assume that a mobile node receives a beacon message from three fixed nodes.

The mobile node can determine that the received signal strength of the first fixed node is the largest for most of the time interval.

The mobile node selects a first fixed node. That is, it may be determined that the mobile node is located in the unit area of the first fixed node.

6A and 6B are signal flow diagrams illustrating a position recognition operation according to a second embodiment of the present invention.

Referring to FIG. 6A, a location aware system includes a location aware server 10, fixed nodes 20, 30, and a mobile node 40.

The mobile node 40 may operate in an idle mode, and may be switched to a wake-up mode through a sensor included therein (step 210). In the wake-up mode, the mobile node 40 may perform a location recognition operation.

The mobile node 40 may send a beacon request message (location aware request message) to the fixed nodes to receive the beacon message (location aware message).

The mobile node 40 transmits a first beacon request message to the first fixed node 20 (step 211).

The mobile node 40 transmits a second beacon request message to the second fixed node 30 (step 212).

Upon receiving the first beacon request message, the first fixed node 20 measures the signal strength of the first beacon request message (step 213). The first fixed node 20 generates a first beacon message. The first beacon message includes identifier information of the first fixed node 20 and signal strength information measured through the first beacon request message.

When the second fixed node 30 receives the second beacon request message, the second fixed node 30 measures the signal strength of the second beacon request message (step 214). The second fixed node 30 generates a second beacon message. The second beacon message includes identifier information of the first fixed node 20 and signal strength information measured through the second beacon request message.

The first fixed node 20 transmits the generated first beacon message to the mobile node 40 (step 215).

The second fixed node 20 transmits the generated second beacon message to the mobile node 40 (step 216).

The mobile node 40 receiving the first beacon message and the second beacon message measures the signal strength of each of the first beacon message and the second beacon message (step 217). In addition, the mobile node 40 extracts the signal strength included in each of the first beacon message and the second beacon message.

The mobile node 40 transmits a third beacon request message to the first fixed node 20 (step 218).

The mobile node 40 transmits a fourth beacon request message to the second fixed node 30 (step 219).

When receiving the third beacon request message, the first fixed node 20 measures the signal strength of the third beacon request message (step 220). The first fixed node 20 generates a third beacon message. The third beacon message includes identifier information of the first fixed node 20 and signal strength information measured through the third beacon request message.

When the second fixed node 30 receives the fourth beacon request message, the second fixed node 30 measures the signal strength of the fourth beacon request message (step 221). The second fixed node 30 generates a fourth beacon message. The fourth beacon message includes identifier information of the first fixed node 20 and signal strength information measured through the fourth beacon request message.

Referring to FIG. 6B, the first fixed node 20 transmits the generated third beacon message to the mobile node 40 (step 222).

The second fixed node 20 transmits the generated fourth beacon message to the mobile node 40 (step 223).

The mobile node 40 receiving the third beacon message and the fourth beacon message measures the signal strength of each of the third beacon message and the fourth beacon message (step 224). In addition, the mobile node 40 extracts the signal strength included in each of the third and fourth beacon messages.

The mobile node 40 transmits a fifth beacon request message to the first fixed node 20 (step 225).

The mobile node 40 transmits a sixth beacon request message to the second fixed node 30 (step 226).

When the first fixed node 20 receives the fifth beacon request message, the first fixed node 20 measures the signal strength of the fifth beacon request message (step 227). The first fixed node 20 generates a fifth beacon message. The fifth beacon message includes identifier information of the first fixed node 20 and signal strength information measured through the fifth beacon request message.

Upon receiving the sixth beacon request message, the second fixed node 30 measures the signal strength of the sixth beacon request message (step 228). The second fixed node 30 generates a sixth beacon message. The sixth beacon message includes identifier information of the first fixed node 20 and signal strength information measured through the sixth beacon request message.

The first fixed node 20 transmits the generated fifth beacon message to the mobile node 40 (step 229).

The second fixed node 20 transmits the generated sixth beacon message to the mobile node 40 (step 230).

The mobile node 40 receiving the fifth and sixth beacon messages measures the signal strength of each of the fifth and sixth beacon messages (step 231). In addition, the mobile node 40 extracts signal strengths included in each of the fifth and sixth beacon messages.

The mobile node 40 determines the signal strengths measured from the beacon messages for the fixed nodes 20 and 30 (signal strength measured by the mobile node) and the signal strengths included in the beacon messages (by the fixed node). Calculate the average between measured signal strengths). The mobile node selects a fixed node having the largest signal strength, that is, a fixed node having excellent signal strength characteristics through an average calculation (step 232). For example, when the first fixed node 20 is selected, the mobile node 40 generates a node selection message to transmit to the selected first fixed node 20. That is, the mobile node 40 is located in the first unit space 25 of the first fixed node 20. The node selection message may include identifier information of the mobile node 40 or identifier information of the first fixed node 20.

That is, the mobile node 40 is located in the first unit space 25 of the first fixed node 20. For example, when the first fixed node 20 is selected, the mobile node 40 generates a node selection message to transmit to the selected first fixed node 20. The node selection message may include identifier information of the mobile node 40 or identifier information of the first fixed node 20.

The mobile node 40 transmits a node selection message to the selected first fixed node 20 (step 233). The first fixed node 20 generates a location information message. The location information message indicates that the mobile node 40 is located in the first unit space 25 of the first fixed node 20. The location information message may include an identifier of the fixed node 20 and an identifier of the mobile node 40 included in the unit area of the first fixed node 20.

The first fixed node 20 transmits a location information message to the location recognition server 10 (step 234). The location recognition server 10 may identify the location of the mobile node 40 in the first unit space 25 of the first fixed node 20 according to the location information message.

The location recognition server 10 stores and manages the location of the mobile node 40 (step 235). Thereafter, if the location recognizing server 10 needs to provide the location of the mobile node 40, the location recognition server 10 may provide location information of the mobile node.

7 is a graph illustrating signal distortions included in measured signal strengths for position recognition according to an embodiment of the present invention.

Referring to FIG. 7, the mobile node may select a fixed node by using signal strength measured by the mobile node and signal strength information measured by the fixed node.

The horizontal axis of the graph represents time, and the vertical axis represents signal strength, for example, a link quality indicator (LQI). The signal strength of the beacon request message and the signal strength of the beacon message are shown. The difference between the two signal strengths is located near the signal strength of 10 dB. If there is no signal distortion, the signal strength between the beacon request message and the beacon message has a constant difference. Therefore, when the difference in signal strength between the beacon request message and the beacon message increases or decreases, signal distortion occurs.

At this time, the difference between the two signal strengths is greatly increased or decreased based on the average signal strength (ie, 10 dB), resulting in signal distortion. In one example, signal distortion was detected in six portions.

When the mobile node uses the signal strengths measured by the fixed node and the mobile node, it is possible to confirm the occurrence of signal distortion. The mobile node may remove the signal distortion by using a filter or the like where the signal distortion occurs.

The mobile node can reduce the error of position recognition compared to the first position recognition method using only the signal strength measured by the mobile node by removing the signal distortion. Therefore, the mobile node can make a position measurement with improved accuracy.

Here, for the convenience of explanation, signal distortion removal has been described based on one fixed node, but signal distortion may be removed in a similar manner with respect to the remaining base stations.

8 is a graph in which signal distortion is removed from signal strength measured for position recognition in a position recognition operation according to a second embodiment of the present invention.

Referring to FIG. 8, the horizontal axis represents time, and the vertical axis represents signal strength, for example, a link quality indicator (LQI). As an example, assume that a mobile node receives a beacon message from three fixed nodes.

At this time, the mobile node compensates for the signal distortion generated by comparing the signal strength measured at the mobile node and the signal strength measured at the fixed nodes as shown in FIG. 7. The signal strength obtained by compensating for the signal distortion in the mobile node is shown.

It can be seen that the received signal strength of the first fixed node is the largest for most of the time interval.

The mobile node selects a first fixed node. The mobile node may be determined to be located in the unit area of the first fixed node. The mobile node sends a node selection message to the first fixed node.

9 is a flowchart illustrating message transmission between a mobile node and a server according to an embodiment of the present invention.

Referring to FIG. 9, a location aware system includes a location aware server 10, fixed nodes 20 and 30, and mobile nodes 40 and 50. For example, the first mobile node 40 is located in the unit space of the first fixed node 20, and the second mobile node 50 is located in the unit space of the second fixed node 30.

The first mobile node 40 transmits an asynchronous message to the first fixed node 20 (step 310). The first mobile node 40 is connected to the first fixed node 20 managing the unit space in which the first mobile node 40 is located. The first mobile node sends a message via a fixed node discovery procedure, for example, Medium Access Control (MAC) protocol of IEEE 802.15.4.

The first fixed node 20 transmits an acknowledgment (ACK) message to the first mobile node 40 to notify normal reception of the asynchronous message (step 311).

The first fixed node 20 transmits an asynchronous message to the location aware server 10 (step 312).

The location recognition server 10 may generate an asynchronous message for transmission therein (step 313). Location aware server 10 may also receive asynchronous messages from first fixed node 20.

The location aware server 10 may search for a second mobile node 50 to transmit an asynchronous message received from the first fixed node 20 or an internally generated asynchronous message (step 314). The location aware server 10 may search for the second fixed node 30 in which the second mobile node 50 is located by searching a location table (ie, location aware table) for managing location information of the mobile nodes therein. Can be.

The location aware server 10 transmits an asynchronous message to the second fixed node 30 (step 315).

When receiving the asynchronous message, the second fixed node 30 waits for the transmission of the asynchronous message (step 316).

The second mobile node 50 requests the transmission of the asynchronous message to the second fixed node 30 (step 317).

When the asynchronous message transmission is requested from the second mobile node 50 while waiting for the message transmission, the second fixed node 30 transmits an asynchronous message to the second mobile node 50 (step 318).

The second mobile node 50 sends an acknowledgment (ACK) message to the second fixed node 30 to notify normal receipt of the asynchronous message.

When the second fixed node 30 normally receives the asynchronous message, the second fixed node 30 transmits a transmission success message to the location recognition server 10 (320).

Meanwhile, if there is no asynchronous message request from the second mobile node 50 for a predetermined time while waiting for message transmission, the second fixed node 30 stops the message transmission waiting operation (time out operation) (step 321). ).

When the time-out operation is performed, the second fixed node 30 transmits a transmission failure message indicating failure to transmit an asynchronous message to the location aware server 50 (step 322).

Accordingly, when the asynchronous message is normally transmitted in the message transmission standby state, the fixed node 30 performs steps 317 to 320. However, when the asynchronous message is not normally transmitted in the message transmission standby state, the fixed node 30 performs steps 321 to 322.

The first mobile node 40 transmits 20 an asynchronous message status request message to the first fixed node for confirming the transmission status of the asynchronous message (step 323).

The first fixed node 20 transmits a status request message for checking asynchronous message transmission status to the location aware server 10 (step 324).

The location aware server 10 retrieves the asynchronous message transmission state requested by the first mobile node (step 325). The location recognition server 10 may store or manage the asynchronous message transmission state according to the reception of the successful transmission message in step 320 or the transmission failure message in step 322.

The location aware server 10 transmits a status response message according to the asynchronous message transmission to the first fixed node 20 (step 326). The status response message includes information on whether the asynchronous message is transmitted or failed.

The first fixed node 20 transmits a status response message to the first mobile node 40 (step 327). The first mobile node 40 may check whether the asynchronous message is transmitted or failed by receiving the status response message.

As described above, the location-aware server 10 of the present invention may transmit a message through a fixed node where the mobile node is located by searching for the location of the mobile node in a message (eg, asynchronous message) transmission procedure.

FIG. 10 is a diagram illustrating a location table of the location recognition server shown in FIG. 1.

Referring to FIG. 10, the location aware server 10 manages location information for each of the mobile nodes. The location aware server 10 manages a location table including location information for each of the mobile nodes.

(a) represents mobile nodes located in a unit space of fixed nodes. It includes nine fixed nodes E1-E9 for nine fixed nodes. The fixed nodes each form a unit space. The first mobile node A is located in the unit space of the first fixed node E1, and the second mobile node B is located in the unit space of the ninth fixed node E9.

(b) shows a location recognition table managed by the location recognition server 10. The location awareness table includes a stationary node ID, a stationary NwkAddr, an installed physical location, and a detected mobile node.

In the position recognition table, the first mobile node A is included in the first fixed node E1. The network address of the first fixed node E1 is '0xFF01' and the physical location of the first fixed node E1 is 'E10-502'. For example, at 'PM 9:50', the first mobile node A enters the unit space of the first fixed node E1.

In the position recognition table, the second mobile node B is included in the ninth fixed node E9. The network address of the ninth fixed node E9 is '0xFF09', and the physical location of the ninth fixed node E9 is 'E10-509'. For example, at 'PM 9:40', the second mobile node B enters the unit space of the ninth fixed node E9.

The remaining nodes other than the first fixed node E1 and the ninth fixed node E9 in the position recognition table do not include the mobile node.

FIG. 11 is a diagram illustrating a location recognition cycle according to transmission and reception of a location recognition message between a fixed node and a mobile node according to an embodiment of the present invention.

Referring to FIG. 11, section 411 represents one period of the location awareness protocol of the fixed node. In section 411, the fixed node periodically transmits a beacon message to the mobile node, and transmits and receives a message with the mobile node. The fixed node may be variably set in consideration of a system situation in a location recognition period such as a section 411 and a plurality of beacon messages.

Section 412 represents a location recognition section of the mobile node. In section 412, the mobile node can recognize the location of the mobile node through the reception of a beacon message sent from the fixed node. The total time of the 412 section may be equal to the total time of the 411 section or longer than the total time of the 411 section. Even if the mobile node does not acquire synchronization with the fixed node, the mobile node may set the minimum value of the total time of 412 sections to the total time of 411 sections to secure time for receiving all beacon messages from neighboring fixed nodes.

Section 413 is a message reception section. At interval 413, the mobile node can receive a message from the fixed node. When the location of the mobile node is determined, the mobile node requests the message transmission to the fixed node according to the location determination, and receives the message in section 413 from the fixed node.

Section 414 is an activation section of the mobile node. In section 414, the mobile node turns on message reception of the fixed node. Section 414 is a section combining section 412 and 413.

Section 415 is the mobile node sleep time. In section 415, the mobile node operates in a sleep mode for low power. The combined section of section 414 and section 415 is the unit activity cycle of the mobile node. The mobile node may perform location recognition, bidirectional message transmission, and low power operation through a unit activity cycle.

12 is a view for explaining an example of applying a location recognition system according to an embodiment of the present invention in a school classroom.

Referring to FIG. 12, it is assumed that a location recognition system is applied to a school classroom.

The location aware system includes fixed nodes 510, 520, 530, 540, 550 and mobile nodes (eg, 560).

The first fixed node 510 to the fourth fixed node 20 are located in the classroom, and the fifth fixed node 550 is located in the hallway. Each of the fixed nodes 510, 520, 530, 540, and 550 is installed in a separate unit space classroom or hallway.

The mobile node 560 (for example, a student) enters a classroom in which the second fixed node 520 is located, that is, a unit space of the second fixed node 520.

In this case, the mobile node 560 may receive a wake-up signal from a wake-up transmitter 521 attached to an entrance of a lecture room in which the second fixed node 520 is located. In this case, the mobile node 560 may perform a location recognition operation according to the wake-up operation.

The wake-up transmitter 521 may be connected to the second fixed node 520. In addition, the wake-up transmitter 521 may receive mobile node information (eg, mobile node identifier information, etc.) from the mobile node 560 in response to the wake-up signal. The wake-up transmitter 521 uses mobile node information from a satellite recognition server (not shown) through the second fixed node 520 to determine whether the mobile node 560 is authorized to enter or leave the mobile node 560. By comparison). The wake-up transmitter 521 may open the door when the mobile node 560 is authorized to enter. In addition, the wake-up transmitter 521 may block the door if the access of the mobile node 560 is not authenticated.

In addition, when the mobile node 560 enters the classroom, the second fixed node 520 may be selected through the location recognition message. That is, the mobile node 560 is located in the unit space of the second fixed node 520.

The mobile node 560 may periodically update its location information to the location recognition server through the second fixed node 520.

The location recognition server 560 may check attendance of the mobile node 560 together with location recognition of the mobile node 560. The location aware server 560 receives an attendance confirmation message for attendance confirmation to the mobile node.

At this time, the mobile node 560 enters the listening mode. In the listening mode, the mobile node or the location aware server may set a long message transmission / reception period. Thus, traffic for checking the listening state of the mobile node 560 may be reduced.

After the lecture, the mobile node 560 or the location aware server may release the listening mode through a message transmission / reception procedure.

In particular, the location recognition system of the present invention can recognize the location of a mobile node using only signal strength even when there are a plurality of mobile nodes. Therefore, the present invention can manage the location of a plurality of mobile nodes without system load due to location recognition.

13 is a flowchart illustrating an example in which the location recognition system according to the embodiment of the present invention is applied to access control.

Referring to FIG. 13, a location aware system includes a location aware server 10, a fixed node 20, and a mobile node 40.

The mobile node 40 and the fixed node 20 recognize the location of the mobile node through the location recognition operation illustrated in FIG. 4 or 6 (step 610). The mobile node 40 may provide the location recognition server 10 with an identifier of the mobile node 40 and location information (information on the unit space in which the mobile node is located) of the mobile node 40 through periodic location recognition operations. Can be.

The mobile node 40 may determine that the mobile node 40 is located in the unit space of the fixed node 20 through location recognition. At this time, the mobile node 40 transmits a node selection message to the selected fixed node 20 (step 611).

The fixed node 20 transmits a location information message for location recognition of the mobile node 40 to the location recognition server 10 (step 612).

The location recognition server 10 may register location information of the mobile node 40 or update location information through the location recognition table in step 613. That is, the location recognition server 10 manages the location information of the mobile node 40 obtained through the location information message through a location recognition table or the like. The location recognition server 10 may change the location of the mobile node 40, check a moving path, or track a location through the location recognition table.

The mobile node 40 detects the intention to enter through a wake-up sensor such as a door that allows a user having a specific authority to enter (step 614).

The mobile node 40 transmits an access request message for requesting access of the mobile node 40 to the fixed node 20 according to the detection of access determination (step 615).

The fixed node 20 transmits an access request message requesting entry and exit of the mobile node 40 to the location recognition server 10 (step 616).

The location recognition server 10 may select an entrance door requesting entry from the mobile node 40 (step 617). The location recognition server 10 stores information on the door and mobile node or user information that can be accessed through the door.

The location aware server 10 searches for access authority, that is, user authority, of the mobile node 40 through the selected door (step 618).

The location aware server 10 transmits an access permission / deny message to the fixed node 20 to notify the mobile node 40 of the access permission or the access rejection according to the user authority search (step 619).

The location recognition server 10 stores the operation state for the access request of the mobile node (step 620). For example, when access management is applied to an enterprise or the like, the location recognition server 10 may manage commute of the mobile node 40. In addition, when the entrance management is applied to the school, the location recognition server 10 may manage the attendance of the mobile node 40.

The fixed node 20 transmits an access permission / deny message to the mobile node (step 621). In this case, the fixed node 20 may perform an operation corresponding to an access permission / deny message with an opening / closing device such as a door. For example, if the mobile node 40 is allowed to enter, the fixed node 20 may provide a control signal for opening the door to the switchgear. When the mobile node 40 is denied entry, the fixed node 20 may provide a control signal to block the door (or generate an alarm sound) to the switchgear.

In this way, while automating access control by utilizing the location recognition system of the present invention, it is possible to provide a mobile node with a call message by tracking the location of the mobile node in real time.

14A and 14B are flowcharts illustrating an example in which the location recognition system according to an embodiment of the present invention is applied to classroom attendance management.

Referring to FIG. 14A, a location aware system includes a location aware server 10, a fixed node 20, and a mobile node 40.

The mobile node 40 and the fixed node 20 recognize the location of the mobile node through the location recognition operation illustrated in FIG. 4 or 6 (step 710). The mobile node 40 may provide the location recognition server 10 with an identifier of the mobile node 40 and location information (information on the unit space in which the mobile node is located) of the mobile node 40 through periodic location recognition operations. Can be.

The mobile node 40 may determine that the mobile node 40 is located in the unit space of the fixed node 20 through location recognition. At this time, the mobile node 40 transmits a node selection message to the selected fixed node 20 (step 711).

The fixed node 20 transmits a location information message for location recognition of the mobile node 40 to the location recognition server 10 (step 712).

The location recognition server 10 may register the location information of the mobile node 40 or update the location information through the location recognition table in step 713. That is, the location recognition server 10 manages the location information of the mobile node 40 obtained through the location information message through a location recognition table or the like.

When the lecture time arrives, the location recognition server 10 maps the lecture (lecture information) to the lecture room (step 714). The lecture information may include, for example, a lecture name, a lecture code, and the like.

The mobile node 40 transmits a location information message to the fixed node 20 to provide the location information of the mobile node 715 to the location recognition server (step 715).

The fixed node 20 transmits a location information message for providing the location of the mobile node 40 to the location recognition server 10 (step 716).

The location recognition server 10 matches the classroom with the mobile node 40 where the mobile node 40 that has transmitted the location information message is located.

The location recognition server 10 checks attendance in the case of the mobile node 40 of the student for the corresponding classroom through classroom matching (step 718).

When the attendance is checked, the location recognition server 10 transmits an attendance confirmation message to notify the fixed node 719 of the attendance confirmation of the mobile node 40 (step 719). The fixed node 20 transmits an attendance confirmation message to the mobile node 40 (step 720).

Referring to FIG. 14B, the mobile node 40 receiving the attendance confirmation message sets the state of the mobile node 40 to the listening mode (step 721). If the mobile node 40 is located in the lecture room in the listening mode, the mobile node 40 does not report the location information of the mobile node 40 to the location recognition server 10.

The mobile node 40 may transmit an alive packet (eg, a survival message) having a period longer than a period of transmitting the location awareness message to the fixed node 20 (step 722).

The fixed node 20 may transmit an alive packet of the mobile node 40 to the server (step 723).

The mobile node 40 detects the leaving of the mobile node due to a change in the position of the mobile node 40 (step 724).

Upon detecting leaving, the mobile node 40 transmits the leaving message to the fixed node 20 (step 725).

The fixed node 20 transmits an exit message for notifying the location recognition server 10 of the departure of the mobile node 40 (step 726).

The mobile node 40 releases the listening mode set according to the transmission of the exit message (step 727).

The location aware server 40 sets the state of the mobile node 40 that sent the exit message to Away (step 728). The location recognition server 40 may record the student's exit status.

When the lecture time ends, the location recognition server 10 transmits the lecture end message to the fixed node 20 corresponding to the mobile node 40 (step 729). If the position of the mobile node 40 is changed and the mobile node 40 is located in the unit space of another fixed node, the lecture termination message may be transmitted to the other fixed node.

When the fixed node 20 receives the lecture end message, the fixed node 20 transmits the lecture end message to the mobile node 40 (step 730). In addition, the mobile node 40 may release the listening mode by receiving the lecture end message.

15A and 15B are flowcharts illustrating an example in which a location recognition system according to an embodiment of the present invention is applied to a viewing facility reservation.

Referring to FIG. 15A, a location aware system includes a location aware server 10, a fixed node 20, and a mobile node 40.

The mobile node 40 and the fixed node 20 recognize the location of the mobile node through the location recognition operation illustrated in FIG. 4 or 6 (step 810). The mobile node 40 may provide the location recognition server 10 with an identifier of the mobile node 40 and location information (information on the unit space in which the mobile node is located) of the mobile node 40 through periodic location recognition operations. Can be.

The mobile node 40 may determine that the mobile node 40 is located in the unit space of the fixed node 20 through location recognition. At this time, the mobile node 40 transmits a node selection message to the selected fixed node 20 (step 811).

The fixed node 20 transmits a location information message for location recognition of the mobile node 40 to the location recognition server 10 (step 812).

The location recognition server 10 may register location information of the mobile node 40 or update location information through the location recognition table in step 813. That is, the location recognition server 10 manages the location information of the mobile node 40 obtained through the location information message through a location recognition table or the like.

The mobile node 40 receives a reservation request for a viewing facility by the user (step 814). The mobile node 40 may receive a viewing facility reservation request through a user button or a wake up sensor.

The mobile node 40 transmits a reservation request message for reserving the viewing facility to the fixed node 20 (step 815).

The fixed node 20 transmits a reservation request message to the location recognition server 10 (step 816).

The location recognition server 10 confirms the reservation location of the user and the location of the viewing facility through the reservation request message in step 817.

If the distance between the reservation location of the user and the location of the viewing facility is far from the reservation request message and the reservation is impossible, the location recognition server 10 transmits a non-reservation message to the fixed node 20 (step 818).

The fixed node 20 transmits an unreservable message informing the mobile node 40 of the non-reservable (step 819). Here, steps 818 to 819 are procedures for notifying the mobile node 40 of the location recognizing state from the location recognition server 10.

Referring to FIG. 15B, if a reservation is possible through a reservation request message and a location confirmation of a viewing facility through a reservation request message, the location recognition server 10 registers the mobile node 40 in a reservation waiting queue (step 820). ).

The location aware server 10 transmits a reservation success message for the reservation of the mobile node 40 to the fixed node 20 (step 821).

The fixed node 20 transmits a reservation success message to the mobile node 40 (step 822).

When the mobile node 40 receives the reservation success message, the mobile node 40 sets the state of the mobile node 40 to the standby state (step 823).

The location recognition server 10 may detect the start of the entrance by the entrance time of the viewing facility or the manager input (step 824). The location aware server 10 may deliver an entry request message to the mobile nodes of the reservation waiting queue.

When the entrance begins, the location recognition server 10 transmits an entry request message for requesting entry of the mobile node to the fixed node 20 (step 825).

The fixed node 20 transmits an entry request message to the mobile node 40 (step 826).

Upon receiving the entrance request message, the mobile node 40 enters the reserved viewing facility and transmits an entrance message to the fixed node 20 (step 827).

The fixed node 20 transmits an entrance message to the location recognition server 10 (step 828). The location-aware server 10 may check entrance of a viewing facility of the mobile node 40 by receiving an entrance message.

Here, steps 820 to 828 are procedures for notifying the reservation availability state from the location recognition server 10 to the mobile node 40 (and also entering the viewing facility according to the reservation availability).

16 is a flowchart illustrating an operation of reserving a viewing facility of a mobile node according to an embodiment of the present invention.

Referring to FIG. 16, the mobile node 40 performs an initialization operation (S110).

The mobile node 40 operates in an idle state through an initialization operation (S111).

The mobile node 40 detects a reservation request for reserving a viewing facility by a user (or a wake-up sensor) or the like. When the mobile node detects the reservation request, the mobile node makes a reservation request by sending a reservation request message to the location recognition server (S112).

The mobile node 40 checks whether a reservation response message has been received (step S113). If the reservation response message is not received, the mobile node 40 proceeds to step S112 to perform the reservation request again. The reservation response message includes one of a reservation success message or a non-reservation message.

However, upon receiving the reservation response message, the mobile node checks whether the reservation response message is a reservation success message (step S114).

If the reservation response message is not a reservation successful message, the mobile node 40 receives a non-booking message (step S119). Upon receiving the non-reservation message, the mobile node 40 proceeds to step S110 to perform initialization. Upon receiving the unavailable reservation message, the mobile node 40 may display the unavailable information on the viewing facility to the user.

Upon receiving the reservation successful message, the mobile node 40 displays the reservation successful (step S115).

If the reservation is successful, the mobile node 40 enters the standby state (step S116). In the standby state, the mobile node 40 may be located at a place away from the viewing facility.

In the standby state, the mobile node 40 determines whether an entrance message has been received (step S117). If the entry message is not received, the mobile node 40 proceeds to step S116 to maintain the standby state.

Upon receiving the entrance message, the mobile node 40 enters the viewing facility. Upon receipt of the entry message, the mobile node 40 may display the entry status. Through this, the user may show an entrance state of the mobile node 40 to the viewing facility manager when entering the viewing facility and enter the viewing facility.

Upon entering the viewing facility, the mobile node 40 may switch to the entrance state of the viewing facility. In addition, the mobile node 40 may transmit an entrance message for the viewing facility to the location management server 10 through a fixed node corresponding to the unit space of the mobile node.

After entering the viewing facility, the mobile node 40 may proceed to step S110 for initialization.

In addition, the location recognition system of the present invention can be used not only for attendance management in schools, but also for staff management in businesses, patient management in hospitals, child location management for preventing children, and location management of visitors in viewing facilities.

For example, when the present invention is applied to employee management of an enterprise, the mobile node may be a terminal possessed by an employee. In addition, fixed nodes are installed at fixed locations inside or outside the enterprise.

By applying the proposed invention, the enterprise's location-aware server can manage time and attendance, building access and location management of employees through mobile nodes.

When the present invention is applied to patient management in a hospital, the mobile node may be a terminal possessed by a patient or medical personnel, and a caregiver. In addition, the fixed node is installed at a fixed location inside or outside the hospital.

By applying the proposed invention, the hospital's location-aware server can manage the hospital access and location management of patients, medical staff, and caregivers via mobile nodes.

When the present invention is applied to location management for preventing children, the mobile node may be a terminal possessed by an elderly person or a child with dementia. In addition, the fixed node is installed at a fixed position based on a predetermined interval for mobile node position recognition.

By applying the proposed invention, the location-aware server for preventing the loss of children can manage the location of demented elderly people and children through mobile nodes. In addition, the location-aware server for preventing the loss of children may have a function of notifying the guardian when the demented elderly and children are out of the allowed section.

In the present invention, the mobile node may select the fixed node based on the received message received from the fixed nodes or the signal strength of the received signal. In addition, the mobile node may select the fixed node in consideration of the signal strength measured at the fixed node and the signal strength measured at the mobile node.

Therefore, the location recognition server can recognize the location of the mobile node through the unit space of the fixed node selected by the mobile node. The present invention does not require the complicated operation required for location recognition by using only the signal strength at the mobile node for location recognition. Therefore, the present invention may not degrade system performance even if the number of mobile nodes is increased.

10: location aware server 20, 30: fixed nodes
40: mobile node 21: message generator
22: transceiver 23: signal strength measurement unit
41: node state management unit 42: message generator
43: transceiver 44: signal strength measurement unit
45: node selection

Claims (22)

Fixed nodes that broadcast a location awareness message in unit space;
Receive broadcast location-aware messages from each of the fixed nodes, select a fixed node that has transmitted the location-aware message having the largest signal strength among the received location-aware messages, and send a node selection message to the selected fixed node. Transmitting mobile node; And
A location-aware server that receives the mobile node information located in the unit space from the fixed node and manages the location of the mobile node through a location table in which the unit space of the fixed node matches the actual space;
Location recognition system comprising a. The method of claim 1,
And the location aware message is a beacon message. The method of claim 1,
If there is a message to be transmitted to the mobile node, the location recognition server searches the location table to identify the location of the mobile node, and transmits the message through a fixed node of a unit area where the mobile node is located. system. The method of claim 1,
The mobile node broadcasts the location awareness request message,
When the fixed node receives the location awareness request message, the fixed node measures the signal strength of the location awareness request message and broadcasts the measured signal strength in the location awareness message. The method of claim 4, wherein
And when the difference between the signal strength of the location recognition request message and the signal strength of the location recognition message exceeds a preset threshold, the mobile node removes a signal distortion component included between the corresponding signal strengths. The method of claim 4, wherein
And a signal strength of the location awareness request message and at least one of a link quality indicator and a received signal strength indicator. The method of claim 4, wherein
The mobile node selects a fixed node that transmits the location recognition message having the largest average signal strength through an average of the signal strength of the location awareness message and the signal strength of the location awareness request message included in the location awareness message. system. The method of claim 1,
And the mobile node operates in a wake-up mode upon sensing at least one of an operation and an external interrupt of the mobile node. The method of claim 1,
The fixed node is
A message generator for generating a location aware message; And
Location recognition system comprising a message transceiver for transmitting the location awareness message. The method of claim 9,
The mobile node is
A transceiver for receiving location recognition messages from the fixed nodes and transmitting a node selection message including the selected fixed node information;
A signal strength measuring unit measuring signal strength of the location recognition message;
A node selector for selecting a fixed node that has transmitted the location recognition message having the largest signal strength; And
And a message generator for generating the node selection message based on the selected fixed node. The method of claim 1,
The fixed node is
A message transmission / reception unit configured to receive a location recognition request message and to transmit a location recognition message corresponding to the location recognition request message;
A signal strength measuring unit measuring signal strength of the location recognition request message; And
And a message generator for generating a location aware message including the measured signal strength. The method of claim 11,
The mobile node is
A transceiver for receiving location recognition messages from the fixed nodes and transmitting a node selection message including the selected fixed node information;
A signal strength measuring unit measuring signal strength of the location recognition message;
A node selector configured to select a base station having the largest average signal strength obtained through an average of the measured signal strength and the signal strength measured by the fixed node; And
And a message generator for generating the node selection message based on the selected fixed node. Receiving a location awareness message broadcast from fixed nodes at a mobile node and measuring signal strength of the received location awareness message;
Selecting, at the mobile node, a fixed node that broadcasts a location awareness message having the largest signal strength among the measured signal strengths;
Providing information about a mobile node located in a unit space of the fixed node to the location recognition server in the selected fixed node; And
Recognizing a position of the mobile node through a position table in which the received information about the mobile node and the unit space of the fixed node match the actual space;
Location recognition method comprising a. The method of claim 13,
And the location aware message is a beacon message. Sending a location awareness request message from the mobile node to the fixed nodes;
Measuring signal strength of the location recognition request message at the fixed node;
Transmitting a location aware message including the signal strength from each of the fixed nodes to the mobile node;
Measuring signal strength of the location aware messages received from the fixed nodes at the mobile node;
Selecting a fixed node having the largest average signal strength through an average of the signal strength measured at the mobile node and the signal strength measured by the fixed node;
Providing information about a mobile node located in a unit area of the fixed node to the location recognition server in the selected fixed node;
Searching for a fixed node where the mobile node is located if there is a message to be transmitted from the location aware server to the mobile node; And
And transmitting a message from the location aware server to the mobile node through the found fixed node. The method of claim 15,
And the location aware message is a beacon message. The method of claim 15,
Selecting a fixed node having the largest average signal strength is
Removing a signal distortion component included between corresponding signal strengths included in the average signal strength when a preset threshold value between the signal strength measured by the mobile node and the signal strength measured by the fixed node is exceeded; And
And selecting a fixed node having the largest average signal strength based on the average signal strength from which the signal distortion component is removed. The method of claim 15,
And each of the signal strength measured by the mobile node and the signal strength measured by the fixed node includes at least one of a link quality indicator and a received signal strength indicator. A transceiver for receiving the location awareness messages broadcasted from the fixed nodes and transmitting a node selection message including the selected fixed node information;
A signal strength measuring unit measuring a signal strength of the location recognition message;
A node selector for selecting a fixed node that broadcasts a location recognition message having the largest signal strength among the measured signal strengths; And
A message generator for generating a node selection message to be transmitted to the selected fixed node;
A mobile node comprising a. Receiving broadcast location awareness messages from fixed nodes;
Measuring signal strength of the location aware messages;
Selecting a fixed node that has broadcast the location recognition message having the largest signal strength among the measured signal strengths; And
Sending a node selection message to the selected fixed node;
Location recognition method comprising a. The method of claim 19,
The transceiver unit broadcasts a location recognition request message,
And the node selector selects the fixed node that broadcasts the location awareness message having the largest average of the measured signal strength and the signal strength of the location awareness request message included in the location awareness message. 21. The method of claim 20,
Prior to receiving the location aware messages,
Broadcasting the location awareness request message;
The selecting of the fixed node may include selecting a fixed node that broadcasts a location aware message having the largest average of the measured signal strength and a signal strength of the location recognition request message included in the location aware message;
Location recognition method.

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