KR101007725B1 - System for recognizing position and method thereof - Google Patents

Abstract

The present invention relates to a location recognition system and a location recognition method, and a location recognition system according to the present invention includes a location recognition device that transmits a packet for positioning by embedding a tag, and responds to a packet transmitted from the location recognition device. And a coordinator anchor for allocating a time slot by selecting a specific position recognition device for positioning among a plurality of anchors and at least one position recognition device. This allows low-power, high-precision positioning in real time in multi-cell or multi-tag environments of wireless sensor networks by assigning timeslots.

Wireless sensor network, location recognition, time slot, response time

Description

Position Recognition System and Its Position Recognition Method

The present invention relates to a location recognition system and a location recognition method, and more particularly, to a location recognition system and a location recognition method through time slot assignment in a wireless sensor network.

A wireless sensor network (hereinafter abbreviated as WSN) is a network composed of a sensor node, a processor for processing information collected from the sensor node, and a wireless transceiver for transmitting the processed information. Unlike existing networks, it is possible not only to communicate but also to collect automated remote information, which can be widely used for various applications such as scientific, medical, military, and commercial purposes.

The wireless sensor network is developing into a ubiquitous sensor network (hereinafter abbreviated as USN) as the human-centered ubiquitous paradigm is expanded. In particular, the wireless sensor network includes a tagged object or a person with a tag. It can be used in the field of location recognition.

Received Signal Strength Indication (hereinafter abbreviated as RSSI) has been proposed for location recognition in wireless sensor networks. RSSI is a method of measuring the position of the received signal by measuring the strength of the received signal and the measured strength as a distance value. However, this method has a problem in that accurate location information cannot be provided when an error occurs due to a sudden change caused by multipath or reflection due to characteristics of an electromagnetic signal such as radio frequency (RF).

Another location recognition method in the wireless sensor network is a signal elapsed time measurement method (hereinafter referred to as ToF). ToF is a method of determining the location by measuring the elapsed time of a signal transmitted between nodes, which enables more accurate location recognition than RSSI in an environment where interference between nodes is present. However, ToF has a problem that requires clock synchronization.

In order to solve this problem, a symmetric double sided two way ranging method (hereinafter abbreviated as SDS-TWR) has been proposed. SDS-TWR is a method of measuring the response time for a packet transmitted for localization, and uses Chirp Spread Spectrum (CSS) modulation technique to compensate for incorrect time measurement by multipath. The accuracy can be improved.

However, SDS-TWR has a problem that an error due to packet collision or retransmission may occur when a packet is transmitted from another node while measuring response time for packet transmission between two nodes (Point to Point, P2P). In particular, since the wireless sensor network is divided into a plurality of areas called cells, when the wireless sensor network includes multiple cells or multiple tags, coverage areas for signal transmission and reception overlap each other, making accurate location measurement difficult and the efficiency of the wireless sensor network. Can be lowered.

Accordingly, an object of the present invention is to provide a location recognition system and method capable of accurately positioning by supporting multiple cells or multiple tags in a wireless sensor network.

In order to achieve the above object, the present invention proposes a location recognition system and method for accurately identifying a location in a multi-cell or multi-tag environment of a wireless sensor network by assigning timeslots.

More specifically, according to an aspect of the present invention, the above object is, at least one location recognition device for transmitting a packet for positioning by embedding a tag, a plurality of responses in response to a packet transmitted from the at least one location recognition device A location that includes a coordinator anchor that is included in the plurality of anchors and a plurality of anchors and selects a specific location recognition device to determine the location by measuring the packet response time from the plurality of anchors from the at least one location recognition device through the assignment of time slots Achieved by a recognition system.

According to another aspect of the present invention, the above object is a slot allocating unit for allocating a time slot by selecting a specific position recognition device for positioning among a plurality of position recognition devices, and a plurality of coordinator anchors included in the selected specific position recognition device. Coordinator anchor including an information transmitter for transmitting information about the anchor and a slot returner that returns a time slot assigned to the specific location recognition device when the location of the specific location recognition device is determined based on the information on the plurality of anchors transmitted. It is also achieved by

Meanwhile, according to another aspect of the present invention, the above object is an information collecting unit for collecting information on a plurality of anchors including a coordinator anchor that selects a position recognition device through the assignment of time slots and information on the collected plurality of anchors. It is also achieved by a location recognition device including a location recognition unit for transmitting a packet for positioning to a plurality of anchors based on the and the location of the location recognition device by measuring the packet response time from the plurality of anchors.

According to still another aspect of the present invention, an object of the present invention is to select a specific location recognition device for positioning from among a plurality of location recognition devices, and to assign a time slot, and the plurality of anchors including a coordinator anchor to the selected specific location recognition device. Recognizing the position of the coordinator anchor comprising the step of transmitting information about the information and returning the timeslots assigned to the specific position recognition device based on the information on the plurality of anchors transmitted It is also achieved by a scheduling method.

As described above, according to the present invention, there is provided a location recognition system and a location recognition method capable of accurate location recognition in real time in a multi-cell or multi-tag environment in a wireless sensor network through the assignment of time slots.

That is, the position recognition system and the position recognition method according to an embodiment of the present invention can cope with the propagation collision between cells or tags by coordinator anchor control of multiple cells or multiple tags through the assignment of time slots to accurately position There is a measurable effect.

Furthermore, when the time slot is allocated in a multi-cell or multi-tag environment, it is possible to prevent the waste of power by blocking the activation of the cell or the location recognition device that has not been allocated the time slot. Furthermore, there is an effect of supporting handover between multiple cells through expansion of time slot allocation.

Hereinafter, with reference to the accompanying drawings will be described a preferred embodiment of the present invention; In the following description of the present invention, if it is determined that detailed descriptions of related well-known functions or configurations may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, terms to be described below are terms defined in consideration of functions in the present invention, which may vary according to intention or custom of a user or an operator. Therefore, the definition should be based on the contents throughout this specification.

1 is a configuration diagram of a location recognition system 1 in a wireless sensor network according to an embodiment of the present invention.

Referring to FIG. 1, a position recognition system 1 in a wireless sensor network includes a position recognition device 10, an anchor 20, and a coordinator anchor 30.

The location recognition system 1 according to an exemplary embodiment of the present invention may grasp the location of the location recognition device 10 in which a tag is embedded in a wireless sensor network environment including cells serving as a service area.

In this case, the single cell may be configured with four anchors based on a rectangular indoor structure as shown in FIG. 1 when indoor positioning. This is because indoor positioning can satisfy the propagation range by reducing constraints such as thick walls and shielding structures. However, the rectangular interior structure may be various embodiments other than just one embodiment for easily explaining the present invention.

The position recognition device 10 of the position recognition system 1 is included in a cell of the wireless sensor network, and a tag is embedded to transmit a packet for positioning to the anchor 20. Position recognition device 10 may be a plurality in the cell.

The anchor 20 responds to the packet sent from the location recognition device 10. In other words, the packet transmitted by the position recognition device 10 through the two way time of Arrival (hereinafter referred to as dual TOA) does not require mutual synchronization between the position recognition device 10 and the anchor 20. Respond to At this time, the position recognition device 10 may calculate the distance between the position recognition device 10 and the anchor 20 by using the packet response time from the anchor 20. Detailed description of the dual TOA will be described later with reference to FIG. 4.

The anchor 20 may be fixedly placed at predetermined positions in the wireless sensor network. Here, the anchor 20 may transmit or receive the packet to the location recognition device 10 in the coverage area that can transmit and receive the packet.

Meanwhile, the coordinator anchor 30 selects a specific position recognition device among the position recognition devices and allocates a time slot to the selected specific position recognition device. In this case, the selected position recognition device may calculate the relative distance between the specific position recognition device and the anchor 20 by using the packet response time measured by the dual TOA method from the anchor 20. The coordinator anchor 30 may be designated one of the anchors 20 and may be separately designated.

In more detail, the coordinator anchor 30 selects a specific cell or a specific location recognition device in a wireless sensor network environment including multiple cells or multiple tags. In this case, time slots may be allocated to the selected specific cell or the specific location recognition device to control the location of the location recognition device without mutual interference between cells or tags. A scheduling method for location recognition in a multi-cell or multi-tag environment of the coordinator anchor 30 will be described in detail with reference to FIGS. 7 to 9.

2 is a block diagram of the coordinator anchor 30 of the position recognition system according to an embodiment of the present invention.

Referring to FIG. 2, the coordinator anchor 30 includes a slot allocator 300, an information transmitter 310, and a slot return unit 320.

The slot allocator 300 selects a specific location recognition device for location detection among the plurality of location recognition devices and allocates a time slot. That is, when a location recognition device is selected in a wireless sensor network including multiple cells or multiple tags, time slots are time-divided so that time slots do not overlap in time. Accordingly, since there is no signal collision or retransmission phenomenon that may occur during the transmission and reception of packets in a multi-cell or multi-tag environment, the measurement error can be lowered to accurately determine the location.

Further, when the cell included in the wireless sensor network is a multicell, the slot allocator 300 may select a specific cell among the multicells and allocate a time slot. Here, the slot allocator 300 may select a specific location recognition apparatus included in the selected cell and allocate a time slot.

The information transmitter 310 is selected through the slot allocator 300 to transmit information about the plurality of anchors to the location recognition apparatus to which the timeslot is assigned. The information on the plurality of anchors may be the number of anchors or the anchor identifier. In addition, the information of the coordinator anchor 30 included in the plurality of anchors or separately designated may be transmitted.

The slot return unit 320 determines the position of the specific position recognition device through the position recognition device using the information on the plurality of anchors transmitted, and determines the time slots allocated to the specific position recognition device through the slot allocator 300. Returns.

Meanwhile, when the wireless sensor network includes a plurality of cells, the coordinator anchor 30 may be activated according to a preset order of time slots among the coordinator anchors.

3 is a block diagram of a position recognition device 10 of the position recognition system according to an embodiment of the present invention.

Referring to FIG. 3, the location recognizing device 10 includes an information collecting unit 100 and a location recognizing unit 110. At this time, the position recognition device 10 has a tag.

The information collecting unit 100 of the position recognition device 10 collects information on a plurality of anchors including a coordinator anchor. Here, the position recognition device 10 may be selected from a coordinator anchor and assigned with a timeslot to be activated. In other words, when selected from the coordinator anchor is activated through time division, the position can be accurately identified in real time without mutual interference of radio wave coverage between cells or tags.

The location recognizing unit 110 transmits a packet for location determination to the plurality of anchors by using information on the plurality of anchors collected from the information collecting unit 100 and measures the response time of the packets from the plurality of anchors. Find out the location of the positioning device.

In more detail, the location recognizing unit 110 may calculate a distance from the plurality of anchors including the coordinator anchor using the packet response time measured by the dual TOA method. At this time, the packet delay time measurement through the asynchronous method based on the Chirp Spread Spectrum (hereinafter referred to as CSS) can determine the location of the tag recognition device.

4 is a waveform diagram of a signal for locating according to an embodiment of the present invention.

Referring to FIG. 4, the position recognition device 10 may determine the position of the position recognition device 10 through a dual response time measurement method (dual TOA) that does not require mutual synchronization between the position recognition device 10 and the anchor 20. Can be.

The dual TOA method calculates the distance between the position recognition device 10 and the anchor 20 by measuring the propagation delay time using the round trip time and the packet response time of the transmitted / receive packet based on the chirp spread spectrum (CSS). Here, CSS enables long-distance communication at low power and uses a wide band in a very short time, thereby minimizing interference, enabling precise position measurement, especially in indoor environments with high jammers.

In detail, the dual TOA method may calculate a distance between the position recognition device 10 and the anchor 20 as shown in Equation 1 below.

That is, the position recognizing apparatus 10 may obtain two propagation delay times obtained by subtracting a response time from a round trip time of a transmission / reception packet between the position recognition apparatus 10 and the anchor 20. ) Can be calculated. In this case, when each propagation delay time required for transmitting and receiving a packet is the same, the propagation delay time of the echo is the response time from the anchor 20 in the round trip time. 1/2 of time minus time). The position recognition device 10 may calculate the absolute distance between the position recognition device 10 and the anchor 20 by multiplying this time value by a speed of propagation, for example, 300,000 km / sec equal to the speed of light.

At this time, the position recognition device 10 may be embedded with a high-precision timer capable of time measurement of nanoseconds (ns) level for the application of the dual TOA method. For example, based on a 2.4 GHz timer, which is a carrier band, it is possible to measure time in nanoseconds in hardware. Accordingly, it is possible to accurately measure the propagation delay time, and as a result, it is possible to reduce the separate transmission process for the response time by guaranteeing the preset time delay at the transmitting and receiving side at the nanosecond (ns) level. We can calculate the relative distance of.

5 is a flowchart illustrating a location recognition method of a location recognition system according to an exemplary embodiment of the present invention.

Referring to FIG. 5, the coordinator anchor 30 broadcasts a free slot message to the location recognition apparatuses 10a, 10b,..., 10n for slot allocation (S400). In this case, the empty slot message is a message for notifying the location recognition apparatus that there are timeslots available in a corresponding cell to support a multi-tag environment. Furthermore, empty slot messages may be broadcast periodically at predetermined intervals.

The location recognition apparatuses 10a, 10b,..., 10n receiving the broadcasted empty slot message request the assignment of the timeslots to the coordinator anchor 30 (S410).

Then, the coordinator anchor 30 selects a specific location recognition device according to the allocation request of the timeslot (S420). In this case, the coordinator anchor is a scheduling method suitable for each purpose such as first-in first-out (FIFO), round robin, or priority based round robin. Depending on the specific position detection device can be selected.

The time slot is allocated to the selected location recognition apparatus (S430). At this time, the position recognition device that is not selected may be switched to the sleep mode (S440). This is because when the location recognition device does not perform the location recognition process, the device enters the sleep mode to reduce power consumption or to enable charging when the battery is exhausted when the charging circuit is embedded.

Subsequently, the position recognizing apparatuses 10a, 10b, ..., 10n request the coordinator anchor 30 information including the number of anchors or anchor identifiers for the anchors 20a, 20b, ..., 20n (S450). The anchor 30 transmits information on the plurality of anchors 20a, 20b, ..., 20n (S460).

The specific position recognition device that receives the information about the anchors 20a, 20b, ..., 20n transmits a packet for positioning for each of the anchors 20a, 20b, ..., 20n, and a packet response time for the transmitted packet. The position is determined through the dual TOA method of measuring the signal (S470).

Finally, when the position detection of the specific position recognition device is finished, the time slot allocated to the selected position recognition device is returned to the coordinator anchor 30 (S480). Furthermore, when the timeslot assigned to the specific position recognition device is returned, the coordinator anchor 30 may select another position recognition device for position recognition and allocate the time slot. Accordingly, through the location recognition system according to an embodiment of the present invention, it is possible to accurately determine the location of the device in which the tag is embedded in the multi-tag environment of the wireless sensor network.

6 is a flowchart illustrating a location recognition method of a location recognition system according to another exemplary embodiment of the present invention.

FIG. 6 is a diagram illustrating a location recognition method in a multi-cell environment, while FIG. 5 is a diagram illustrating a location recognition method of a location recognition system in a multi-tag environment in a single cell.

In a multicell environment, propagation interference between adjacent cells must be considered. This is because the location recognition error is increased due to the propagation collision phenomenon in the cell boundary area if the information about the slot allocation is not shared between adjacent cells where the coverage areas where radio waves can reach between each cell overlap. This can reduce the efficiency of the wireless sensor network.

Referring to FIG. 6, the specific location recognition apparatus broadcasts an allocation request message of a timeslot (S500). Then, the anchors 20a, 20b, ..., 20n transmit the time slot assignment request message to the coordinator anchor 30 (S510).

In more detail, when the location recognition device broadcasts a time slot assignment request message to a plurality of anchors including a coordinator anchor, the plurality of anchors that receive the time slot assignment request message may transmit the received message to the coordinator anchor. In this case, the plurality of anchors may use Ethernet to transmit the received message to the coordinator anchor. You can also use Power over Ethernet (PoE), which eliminates the need for a separate power cable and power supply. Furthermore, the plurality of anchors may transmit the received message to the coordinator anchor not only wired but also wirelessly. However, the transmission means is not limited to this and various other embodiments are possible.

The coordinator anchor 30 selects a specific cell for location recognition based on the received message and allocates a time slot (S520). The position recognition device included in the cell assigned to the timeslot requests the coordinator anchor information about the anchors 20a, 20b, ..., 20n (S530), and the coordinator anchor 30 includes the anchors 20a, 20b, ..., 20n) is transmitted to the location recognition apparatus (S540). The information on the anchors 20a, 20b, ..., 20n may be the number of anchors or the anchor identifier.

The position recognition device that has received the information about the anchors 20a, 20b, ..., 20n transmits a packet for positioning for each of the anchors 20a, 20b, ..., 20n, and a packet response time for the transmitted packet. The position is determined through the dual TOA method of measuring the signal (S550).

Finally, when the position detection of the specific position recognition device is finished, the time slot allocated to the selected position recognition device is returned to the coordinator anchor 30 (S560). Furthermore, when the timeslot assigned to the specific position recognition device is returned, the coordinator anchor 30 may select another position recognition device for position recognition and allocate the time slot. Furthermore, the above-described process may be repeated by selecting another cell not selected. Accordingly, the location recognition system according to an embodiment of the present invention supports the multi-cell and multi-tag environments of the wireless sensor network, thereby enabling accurate location detection of the location recognition device.

Hereinafter, a scheduling method for position recognition of the coordinator anchor according to various embodiments of the present disclosure will be described in detail with reference to FIGS. 7 to 9. 7 and 8 are diagrams illustrating a scheduling method for position coordinator anchor position recognition for multiple tags in a single cell of the wireless sensor network, Figure 9 is a scheduling method for position recognition of coordinator anchors in multiple cells. It is a figure explaining.

7 is a flowchart illustrating a scheduling method for position recognition of a coordinator anchor according to an embodiment of the present invention.

Referring to FIG. 7, in the single cell environment of the wireless sensor network, the coordinator anchor selects a specific location recognition device for location detection among the plurality of location recognition devices and allocates a time slot (S100). In this case, the coordinator anchor may select a specific location recognition device through a method such as FIFO, round robin, or priority based round robin.

The coordinator anchor transmits information on a plurality of anchors including the coordinator anchor to the selected specific position recognition device (S110). That is, information of a plurality of anchors including the number of anchors or anchor identifier information may be transmitted according to the request for information from the selected location recognition device.

Subsequently, when the position of the specific position recognition device is determined based on the information on the transmitted anchor, the coordinator anchor returns a time slot allocated to the position recognition device (S120). The return of the allocated timeslot here means that the location measurement of the selected location recognition device has been completed and the use of the allocated timeslot has been completed.

If the location-awareness calculation of the location-aware device assigned to the time slot is not completed within the preset time, the coordinator anchor broadcasts the time slot termination message to force the use of the time slot for efficient use of the entire wireless sensor network. You can.

Furthermore, when the time slot allocated to the specific location recognition device is returned, the coordinator anchor selects another location recognition device for location recognition and allocates the time slot (S130). This process is repeated to enable the location of all location-aware devices with tags included in a single cell of the wireless sensor network. Therefore, even in the multi-tag environment of the wireless sensor network, the location of the location recognition device can be accurately determined by the scheduling method through time division of the coordinator anchor.

8 is a flowchart illustrating a method of allocating timeslots of the coordinator anchor of FIG. 7.

Referring to FIG. 8, the coordinator anchor receives a request for allocation of a timeslot from a plurality of location recognition apparatuses that receive a broadcasted free slot message by broadcasting a free slot message (S102). Empty slot messages may be broadcast periodically at preset intervals.

Subsequently, the coordinator anchor selects a specific location recognition device among the plurality of location recognition devices and allocates a time slot according to a request for allocation of time slots of the plurality of location recognition devices (S104). Here, the coordinator anchor may use a carrier sense multiple access (CSMA) and collision avoidance (CA) method when transmitting a packet. CSMA is a method of detecting a carrier to determine whether a line is available or to initiate or wait for a connection. The coordinator anchor can control the signal collision between each tag embedded in the positioning device based on the CSMA and CA methods.

Subsequently, the coordinator anchor may switch the non-selected position recognition device to a sleep mode (S106). Accordingly, when the location recognition device does not perform the location recognition process, the device enters the sleep mode, thereby reducing power consumption or charging when the battery is exhausted when the charging circuit is built.

9 is a flowchart illustrating a scheduling method for position recognition of a coordinator anchor according to another embodiment of the present invention.

Referring to FIG. 9, in the multi-cell environment of the wireless sensor network, the coordinator anchor selects a specific cell for position measurement among a plurality of cells and allocates a time slot according to a time slot allocation request from a position recognition device for determining a position ( S200).

In this case, the time slot assignment request may be made from a plurality of anchors that have received a request message for time slot assignment. That is, when a specific location recognition device broadcasts a time slot assignment request message to a plurality of anchors including a coordinator anchor, the plurality of anchors receiving the time slot assignment request message transmits the received message to the coordinator anchor via Ethernet. Can be. In this case, the coordinator anchor may select a specific cell for positioning based on the received message.

Subsequently, the coordinator anchor transmits information about the plurality of anchors including the coordinator anchor located in the selected specific cell to the location recognition apparatus (S210). The information on the plurality of anchors may be the number or anchor identifier of each anchor.

Subsequently, when the coordinator anchor determines the position of the position recognition device based on the information on the plurality of transmitted anchors, the coordinator anchor returns a time slot allocated to the position recognition device (S220). In this way, time slots can be assigned to other location recognition devices included in the selected cell to determine the location of all location recognition devices. Furthermore, when the positioning of all the position recognition apparatuses included in the selected cell is completed, the coordinator anchor may select another cell not selected and repeat the above-described method.

Accordingly, the coordinator anchor according to an embodiment of the present invention may select a specific cell or a specific position recognition device and allocate a time slot. Therefore, it is possible to control so that the position of the tag recognition device is embedded in real time without mutual collision or interference of radio waves transmitted and received in a multi-cell and multi-tag environment.

10 is a flowchart illustrating a position recognition method of the position recognition device according to an embodiment of the present invention.

Referring to FIG. 10, the location recognition device is selected from the coordinator anchor located in the wireless sensor network for location recognition and is assigned a time slot (S300). When the timeslot is allocated, information on a plurality of anchors including the coordinator anchor is requested and received (S310).

Subsequently, the location recognition device determines the location of the location recognition device by measuring a packet response time for a packet transmitted to the plurality of anchors based on the received information on the plurality of anchors (S320). In this case, the propagation delay time may be measured using the dual response time measuring method (double TOA) described above with reference to FIG. 4, and the distance between the selected position recognition device and the plurality of anchors may be calculated using the measured propagation delay time.

Finally, if the location of the location recognition device is determined, the allocated time slot is returned to the coordinator device (S330). At this time, the position recognizing device that returns the allocated time slot can be switched back to the sleep mode to prevent waste of power.

Hereinafter, the location recognition process of the location recognition system in a multi-cell or multi-tag environment according to various embodiments of the present disclosure will be described in detail with reference to FIGS. 11 to 15.

11 is a reference diagram for explaining a position recognition process of a position recognition system according to an embodiment of the present invention.

Referring to FIG. 11, the position recognition system according to an exemplary embodiment of the present invention enables accurate position measurement in real time in a multi-tag environment within a single cell. Here, a single cell may be composed of four anchors, since indoor positioning can satisfy the propagation range by reducing constraints such as thick walls and shielding structures. However, the rectangular interior structure may be various embodiments other than just one embodiment for easily explaining the present invention.

When the cell is composed of four anchors as shown in FIG. 11, one of the four anchors may be set as the coordinator anchor. Or the coordinator anchor can be specified separately. At this time, the coordinator anchor can control the position measurement in a dual TOA method through the time slot assignment to prevent the occurrence of signal collision between the transmitting and receiving sides. For example, the coordinator anchor can support a multiple tag environment by selecting a specific location recognition device for location detection among the plurality of location recognition devices with a tag as shown in FIG.

Here, the selected position recognition device can determine the exact position of the position recognition device by calculating the distance with a plurality of anchors located in a single cell through the dual TOA method as shown in FIG.

12 is a reference diagram for explaining a scheduling process for position recognition of a coordinator anchor according to an embodiment of the present invention.

FIG. 11 illustrates a scheduling process for location recognition in a multi-cell environment, while FIG. 11 illustrates a scheduling process for location recognition in a single cell environment. In particular, FIG. 12 illustrates one block in which four cells are adjacent to each other by way of example.

In a multi-cell environment, a specific location recognition device with a built-in tag may broadcast a time slot assignment request message to a plurality of anchors including a coordinator anchor as shown in FIG. Then, as shown in FIG. 12B, the plurality of anchors that receive the time slot allocation request message may transmit the received message to the coordinator anchor via Ethernet. In this case, the coordinator anchor may select a specific cell for positioning based on the received message.

All position recognition devices in the selected cell can identify each position according to the time slot assignment order of the coordinator anchor. Furthermore, when the positioning of all the position recognition devices included in the selected cell is finished, other cells which are not selected through the coordinator anchor are selected, and thus, the position recognition device located in the other cell can be located through the time slot assignment. Therefore, the coordinator anchor according to an embodiment of the present invention can control the location of the location recognition device in real time by supporting a multi-cell and multi-tag environment through a time slot allocation method.

13 and 14 are reference diagrams for explaining a scheduling process for position recognition of a coordinator anchor according to another embodiment of the present invention.

11 and 12 illustrate a scheduling process for position recognition when there is only one coordinator anchor controlling the position recognition device. FIGS. 13 and 14 illustrate a scheduling process for position recognition when there are a plurality of coordinator anchors. It is a figure explaining. In particular, FIGS. 13 and 14 illustrate an embodiment of one zone composed of nine adjacent blocks.

When a plurality of coordinator anchors exist in the wireless sensor network as shown in FIG. 13, the position recognition system according to an embodiment of the present invention as shown in FIG. 14 activates a coordinator anchor for allocating time slots according to a preset time slot assignment order. can do.

Specifically, as shown in FIG. 14A, when each coordinator anchor formed in four blocks corresponding to ① is activated, the activated coordinator anchor can control a position recognition device located in each block. Subsequently, as shown in FIG. 14B, each coordinator anchor formed in two blocks corresponding to ② may be activated. Furthermore, as shown in FIG. 14C, each coordinator anchor formed in two blocks corresponding to ③ may be activated. Finally, as shown in FIG. 14D, one block in the center corresponding to ④ may be activated.

In this case, when the control role of the position coordinator of the coordinator anchor activated in accordance with the preset time slot assignment sequence is terminated, the other coordinator anchor is activated to propagate between all the cell and tag embedded in the wireless sensor network. Interference can be prevented.

15 is a reference diagram for explaining a scheduling process for position recognition of a coordinator anchor according to another embodiment of the present invention.

Referring to FIG. 15, when a zone of FIG. 14 is expanded and four zones are adjacent to each other to form one section, the coordinator anchor is activated according to a preset time slot order as shown in FIG. 15. Interference in the entire network can be avoided and handover between cells is possible.

Meanwhile, even when the wireless sensor network is extended to a plurality of sections, the location recognition system according to an embodiment of the present invention can recognize the location of the location recognition device precisely in real time through time slot assignment through the above-described method. .

In summary, the location recognition system and its location recognition method according to an embodiment of the present invention can recognize the location in real time without collision of radio waves transmitted and received through the assignment of time slots in a multi-cell and multi-tag environment of a wireless sensor network. Can be. At this time, the position recognition device may identify the position through a dual TOA method in which a tag is embedded to transmit a packet for positioning to a plurality of anchors and measure a packet response time for the transmitted packet.

Furthermore, the location recognition system and its location recognition method according to an embodiment of the present invention may support handover between multiple cells in a multi-cell or multi-tag environment, and may be configured to allocate a cell or location recognition device that is not allocated according to the time slot assignment. By shutting off activation, low-power, high-precision position measurement is possible.

So far I looked at the center of the preferred embodiment for the present invention. Those skilled in the art will appreciate that the present invention can be implemented in a modified form without departing from the essential features of the present invention. Therefore, the disclosed embodiments should be considered in descriptive sense only and not for purposes of limitation. The scope of the present invention is shown in the claims rather than the foregoing description, and all differences within the scope will be construed as being included in the present invention.

1 is a configuration diagram of a location recognition system in a wireless sensor network according to an embodiment of the present invention;

2 is a block diagram of a coordinator anchor of the position recognition system according to an embodiment of the present invention,

3 is a configuration diagram of a position recognition device of a position recognition system according to an embodiment of the present invention;

4 is a waveform diagram of a signal for locating according to an embodiment of the present invention;

5 is a flowchart illustrating a location recognition method of a location recognition system according to an embodiment of the present invention;

6 is a flowchart illustrating a position recognition method of a position recognition system according to another embodiment of the present invention;

7 is a flowchart illustrating a scheduling method for position recognition of a coordinator anchor according to an embodiment of the present invention;

8 is a flowchart illustrating a method of allocating timeslots of the coordinator anchor of FIG. 7;

9 is a flowchart illustrating a scheduling method for position recognition of a coordinator anchor according to another embodiment of the present invention;

10 is a flowchart illustrating a position recognition method of a position recognition device according to an embodiment of the present invention;

11 is a reference diagram for explaining a position recognition process of a position recognition system according to an embodiment of the present invention;

12 is a reference diagram for explaining a scheduling process for position recognition of a coordinator anchor according to an embodiment of the present invention;

13 and 14 are reference diagrams for explaining a scheduling process for position recognition of a coordinator anchor according to another embodiment of the present invention;

15 is a reference diagram for explaining a scheduling process for position recognition of a coordinator anchor according to another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

1: Position Recognition System 10: Position Recognition Device

20: anchor 30: coordinator anchor

100: information collecting unit 110: location recognition unit

300: slot allocation unit 310: information transmitting unit

320: slot return unit

Claims (16)

In a location recognition system in an asynchronous wireless sensor network in a multi-tag or multi-cell environment, At least one location recognition device having a tag embedded therein to transmit a packet for location recognition; A plurality of anchors responsive to packets transmitted from said at least one location recognition device; And When the at least one location recognition device requests time slot allocation for location recognition, a coordinator anchor selecting a specific location recognition device and assigning time slots according to a preset selection method among the location recognition devices requesting time slot allocation is selected. Include, The selected specific location recognition device is a location recognition system for determining the location by measuring the packet response time from the plurality of anchors. In the coordinator anchor in an asynchronous wireless sensor network in a multi-tag or multi-cell environment, A slot allocator configured to select a specific location recognition device according to a preset selection method among the location recognition devices that request time slot allocation for location recognition and to allocate a time slot; An information transmitter which transmits information on a plurality of anchors including the coordinator anchor to the selected specific position recognition device; And And a slot return unit that returns a time slot allocated to the specific location recognition device when the location of the specific location recognition device is determined based on the information on the plurality of anchors. The method of claim 2, wherein the slot allocation unit Coordinator anchor to select a specific cell of the plurality of cells included in the wireless sensor network, and to select the specific location recognition device included in the selected specific cell to allocate a time slot. The method of claim 2, The coordinator anchor is activated according to the order of allocation of a predetermined time slot of at least one coordinator anchor included in the wireless sensor network having a plurality of cells. A location recognition device in an asynchronous wireless sensor network in a multi-tag or multi-cell environment, An information collection unit for requesting the coordinator anchor for time slot allocation to select a location and selecting the time slot to collect information on a plurality of anchors including the coordinator anchor through time slot assignment of the coordinator anchor; And And a location recognizing unit configured to determine a location of the location recognizing apparatus by transmitting a packet for positioning to the plurality of anchors based on the collected information about the plurality of anchors, and measuring a packet response time from the plurality of anchors. Position recognition device. The method of claim 5, The position recognition device is activated by receiving the time slot from the coordinator anchor. The apparatus of claim 5, wherein the location recognizing unit A position recognition device for determining the position by calculating the distance to the plurality of anchors including the coordinator anchor based on the measured packet response time. The apparatus of claim 5, wherein the location recognizing unit A location recognition device for identifying the location of the location recognition device by measuring packet delay time through a chirp spread spectrum (CSS) based asynchronous method. A scheduling method for position recognition of a coordinator anchor in an asynchronous wireless sensor network in a single cell environment including multiple tags, Allocating a time slot by selecting a specific location recognition device requesting time slot allocation for location recognition among a plurality of location recognition devices included in the wireless sensor network according to a preset selection method; Transmitting information about a plurality of anchors including the coordinator anchor to the selected specific location recognition device; And And returning a time slot allocated to the specific location recognition device when the location of the specific location recognition device is determined based on the transmitted information about the plurality of anchors. 10. The method of claim 9, wherein the step of assigning a time slot by selecting the specific location recognition device according to a preset selection method Broadcasting an empty slot message and requesting allocation of a timeslot from the plurality of location recognition apparatuses that have received the broadcasted empty slot message; And And assigning the time slot by selecting the specific location recognition device among the plurality of location recognition devices according to the allocation request of the time slot. The method of claim 10, wherein the step of allocating a time slot by selecting the specific position recognition device according to the set selection method comprises: The method of claim 1, further comprising the step of switching the at least one position recognition device that is not selected to the sleep mode. The method of claim 9, And assigning a time slot by selecting another location recognition device for location recognition when the time slot allocated to the specific location recognition device is returned. A scheduling method for position recognition of a coordinator anchor in an asynchronous wireless sensor network in a multi-cell environment including multiple tags, Selecting a specific cell among a plurality of cells included in the wireless sensor network, selecting a specific location recognition device that requests time slot allocation for location recognition among a plurality of location recognition devices of the selected specific cell according to a preset selection method Assigning timeslots; Transmitting information about a plurality of anchors including the coordinator anchor located in the selected specific cell to the selected specific location recognition device; And And returning a time slot allocated to the specific location recognition device when the location of the specific location recognition device is determined based on the transmitted information about the plurality of anchors. The method of claim 13, The time slot assignment request of the step of assigning the time slot is scheduling method for the position recognition of the coordinator anchor is made from the plurality of anchors received the request message for the time slot assignment. A location recognition method of a location recognition device in an asynchronous wireless sensor network including multiple tags or multiple cells, Requesting a time slot assignment to a coordinator anchor for location recognition and receiving a time slot from the coordinator anchor when the time slot is allocated according to a preset selection method; Receiving information about a plurality of anchors including the coordinator anchor through the assigned timeslot; Determining a location of the location recognizing apparatus by measuring a packet response time for a packet transmitted to the plurality of anchors based on the received information about the plurality of anchors; And Determining the location of the location recognition device and returning the assigned time slot to the coordinator device. The method of claim 1, The preset selection method is any one of a first-in first-out (FIFO), a round robin method or a priority based round robin method.

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