KR20060009795A - Method for location based service in coordinator-based wireless network - Google Patents

Abstract

A location tracking method in a coordinator based wireless network is provided.

A location tracking method in a coordinator-based wireless network according to an embodiment of the present invention comprises the steps of transmitting a first frame including its identifier and time information to the wireless network to know its location information by a device combined with the wireless network; And receiving, by the device, a second frame including location information of the device transmitted from the wireless network in response to the first frame.

Wireless Network, 802.15.4, Location Based Service, UWB, 802.15.4a

Description

Location tracking method in coordinator-based wireless network {Method for location based service in coordinator-based wireless network}

1 is a block diagram illustrating a cluster-tree network of 802.15.4 according to an embodiment of the present invention.

2 is a flowchart illustrating a process in which a tracking device requests a coordinator to recognize a magnetic location according to an embodiment of the present invention.

3 is a flowchart illustrating a process of requesting a remote location recognition for a tracking device by a coordinator according to another embodiment of the present invention.

4 is a flowchart illustrating a process in which a device other than a PAN coordinator or a cluster header requests location tracking of another device according to an embodiment of the present invention.

FIG. 5 is a flowchart illustrating a process of tracking a location of a tracking device existing outside a cluster including a PAN coordinator according to another embodiment of the present invention.

6 is a flowchart illustrating a process of tracking a location of a tracking device existing outside of a relay device according to another embodiment of the present invention.

7 is a conceptual diagram illustrating location tracking through a TOA scheme according to an embodiment of the present invention.

8 is a block diagram showing location tracking through the TDOA method according to an embodiment of the present invention.

9 is a frame format of the MAC layer for implementing a location tracking function in 802.15.4 according to an embodiment of the present invention.

10 is a block diagram illustrating command parameters of a frame according to an embodiment of the present invention.

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

31: PAN coordinator 11, 21: Cluster header (coordinator)

101, 102: tracking device 301, 302, 401, 402: reference device

The present invention relates to a location tracking method in a coordinator based wireless network.

The current network is not a network between computers, but connects all devices that want to exchange data with other devices. In the past, building a network via wire has been a major issue, but the need for wireless communication technology has been highlighted by new wiring work and mobility limitations. Wireless Networking Technology Wireless Local Area Network (WLAN) technology in the 50 ~ 100m area and Wireless Personal Area Network (WPAN) in the narrow area of less than 10m are currently standardized, but considering the activity area and mobility in the home In order to apply to home appliances, WPAN technology, which consumes less power and enables ad hoc networking between devices, may be more suitable.

The coordinator-based wireless network refers to a network through which a coordinator manages a communication time point and a competition mode. Coordinator-based wireless networks include many of the protocols defined within the 802.15 working group.

The IEEE 802.15 Working Group is a group for WPANs that has established the WPAN standard, which consists of mobile computing devices within a short distance network. The WPAN standard is divided into four tasking groups (TGs), which are working on WPAN standardization based on Bluetooth 1.x at TG1, and at TG2, research on co-existence of wireless networks. have. TG3 is researching a technology (UWB, Ultra Wideband) that consumes less power and provides a high data rate of 20Mbps or more, and TG4 has a technology suitable for low-speed data transmission of up to 250Kbps with very low power consumption. I am researching.

802.15.4, called LR-WPAN (Low Rate-WPAN), is aimed at low-cost communication networks with simple architectures connected wirelessly in applications requiring low data rates. The IEEE 802.15.4 standardization (ZigBee), which began in July 2000, is a group that establishes standards for low-speed, low-cost, low-power wireless transmission technology for use in wireless integrated remote controllers, consumer electronics controllers, building controls, and toys. In 2003, the standards for the physical layer and the MAC layer were finalized. In the standard, the transmission speed is 250kbps (16 channels in 2.4GHz ISM band) and 40kbps / 20kbps (10 channels in 915MHz band / 1 channel in 868MHz band) depending on the frequency. It is possible to set.

Based on the results of the IEEE 802.15.4 standard activities, specific standard activities for the upper layers including the network layer are being carried out by a cooperative organization called ZigBee. Philips, Motorola, Honeywell, Mitsubishi, Invensys, Samsung to complement existing standards for network protocols and ad-hoc wireless networking between decentralized devices With this promoter, about 50 companies are participating in the ZigBee Alliance as members. Checklist work and detailed application definition are in progress for specific interoperability test. The objectives of IEEE 802.15.4 are 1) low power consumption, 2) low cost, and 3) minimization of infrastructure, which meets the need for wireless integration in sensors and control devices.

802.15.4a, on the other hand, is a new networking technology aimed at providing precise location awareness that is the basis of the emerging ubiquitous environment. It aims to standardize low-speed location-based networks using ultra wideband (UWB).

802.15.4a is the underlying networking technology of 802.15.4, and uses the UWB (Ultra Wideband) as the physical layer (PHY) while still using the medium access layer (MAC) of 802.15.4. However, 802.15.4 does not define the protocol related to location tracking. Therefore, it is necessary to add location-based technology to the coordinator-based wireless network to implement the location tracking technology of 802.15.4a. In addition, by allowing the user of the device to track their location at the time of location tracking, it is possible to protect the privacy.

An object of the present invention is to provide a location tracking function in a wireless network based on a coordinator.

Another technical problem to be achieved by the present invention is to enable location tracking of a device based on a wireless communication technology such as UWB by using a location tracking function of a coordinator-based wireless network.

The objects of the present invention are not limited to the above-mentioned objects, and other objects that are not mentioned will be clearly understood by those skilled in the art from the following description.

The present invention relates to a location tracking method in coordinator based wireless network communication.

In a location tracking method in coordinator-based wireless network communication according to an embodiment of the present invention, a device combined with a wireless network transmits a first frame including its identifier and time information to the wireless network to know its location information. And receiving, by the device, a second frame comprising location information of the device transmitted from the wireless network in response to the first frame.

According to another exemplary embodiment of the present invention, a location tracking method in coordinator-based wireless network communication is performed by a first device coupled to a wireless network to the wireless network to know location information of a second device. Transmitting a first frame including an identifier, and receiving, by the first device, a second frame comprising location information of the second device transmitted from the wireless network in response to the first frame. .

A location tracking method in coordinator-based wireless network communication according to another embodiment of the present invention includes a first frame including an identifier of the first device and an identifier of the second device that requested location tracking of the second device from the wireless network. Receiving by the second device and transmitting, by the second device in response to the first frame, a second frame including an identifier of the first device and an identifier and time information of the second device to the wireless network; It includes.

A location tracking method in coordinator-based wireless network communication according to another embodiment of the present invention includes a first frame including an identifier of the first device and an identifier of the second device that requested location tracking of the second device from the wireless network. Determining, by the second device, whether to accept or reject the location tracking, and if the determination results in the location tracking, the second device responds to the first frame by the second device in response to the first frame. And transmitting a second frame including an identifier of the first device, an identifier and time information of the second device.

In another embodiment of the present invention, a location tracking method in coordinator-based wireless network communication includes receiving a first frame including an identifier and time information of the device transmitted by another device, and using the time information. Obtaining location calculation information used to calculate the location of the &lt; RTI ID = 0.0 &gt; and &lt; / RTI &gt; sending a second frame comprising an identifier of the device and the location information to a network coordinator.

According to another embodiment of the present invention, a location tracking method in coordinator-based wireless network communication includes an identifier of a first device requesting location tracking of the second device transmitted by a second device, an identifier and time information of the second device. Receiving a first frame comprising a; Obtaining position calculation information used to calculate the position of the second device using the time information; And Identifier of the first device and identifier of the second device and the And sending a second frame containing the location information to the network coordinator.

A location tracking method in coordinator-based wireless network communication according to another embodiment of the present invention comprises the steps of: receiving a plurality of frames from the network including a device identifier and location information of the device, using the location information Calculating a location of the device, and transmitting a frame including the calculated location information to the device.

A location tracking method in coordinator-based wireless network communication according to another embodiment of the present invention comprises a plurality of location information including an identifier of a first device requesting location tracking of a second device and an identifier and location information of the second device. Receiving frames from a network, calculating a location of the second device using the location information, and transmitting a frame including the calculated location information to the first device.

A location tracking method in coordinator-based wireless network communication according to another embodiment of the present invention includes a first frame including an identifier of a first device requesting location tracking of a second device and an identifier of the second device from a network. Receiving, transmitting the first frame to a second device in the network, receiving a second frame from the second device indicating the denial of location tracking, and telling the first device the second frame. Transmitting a step.

According to another embodiment of the present invention, a location tracking method in coordinator-based wireless network communication includes: an identifier of the first device transmitted by a first device for location tracking of a second device by the coordinator of the first wireless network; Receiving a first frame comprising an identifier of a second device, wherein the coordinator of the first wireless network informs the coordinator of the second wireless network the first wireless network identifier and the first device identifier and the identifier of the second device; Transmitting a second frame comprising: the first wireless network identifier, the first device identifier, the identifier of the second device, and the first device transmitted by the coordinator of the second wireless network in response to the second frame; A second frame including location information of a second device, Receiving sperm, and transmitting, by the coordinator of the first wireless network, a fourth frame including location information of the second device to the first device.

According to another embodiment of the present invention, a location tracking method in coordinator-based wireless network communication includes: an identifier of the first device transmitted by a first device for location tracking of a second device by the coordinator of the first wireless network; Receiving a first frame comprising an identifier of a second device, wherein the coordinator of the first wireless network informs the coordinator of the second wireless network the first wireless network identifier and the first device identifier and the identifier of the second device; Transmitting a second frame comprising: if the second device receiving the second frame rejects the location tracking, the first wireless network identifier and the identifier of the first device in response to the second frame; Coordination of the first wireless network with a third frame comprising an identifier of the second device Comprising: a reception and a step of a coordinator of the first wireless network sends a fourth frame containing information that the second device rejects the location to the first device.

According to another embodiment of the present invention, a location tracking method in coordinator-based wireless network communication includes a first wireless network identifier transmitted by a coordinator of a first wireless network and an identifier of a first device requesting location tracking of a second device. Receiving, by a coordinator of a second wireless network, a first frame that includes an identifier of a second device, wherein the coordinator of the second wireless network sends the first wireless network identifier to the second device that has joined the second wireless network; Transmitting a second frame comprising an identifier of the first device and an identifier of the second device, from the second wireless network the identifier of the first wireless network identifier and the first device, and of the second device A plurality of thirds including an identifier and location information of the second device Receiving frames by the coordinator of the second wireless network, by the coordinator of the second network to calculate the location of the second device using the location information of the second device, and by the second network coordinator And transmitting a fourth frame including the first wireless network identifier, the first device identifier, the identifier of the second device, and the calculated location information of the second device to the first wireless network coordinator.

According to another embodiment of the present invention, a location tracking method in coordinator-based wireless network communication includes a first wireless network identifier transmitted by a coordinator of a first wireless network and an identifier of a first device requesting location tracking of a second device. Receiving a first frame comprising an identifier of a second device, wherein the coordinator of the second wireless network includes the first wireless network identifier and an identifier of the first device and an identifier of the second device Transmitting the first wireless network identifier transmitted by the third wireless network, the identifier of the first device, the identifier of the second device, and the calculated position information of the second device. Receiving a third frame comprising a coordinator of the second wireless network, and The second wireless network coordinator sends a fourth frame to the first wireless network coordinator including the first wireless network identifier, the first device identifier, the identifier of the second device, and the calculated location information of the second device. Transmitting.

The terms used in the present specification are as follows.

Coordinator-based wireless network

A network type in which a wireless network device acting as a coordinator (hereinafter, referred to as a 'coordinator-based wireless network') forms a single wireless network centered on a coordinator, and a plurality of coordinator-based wireless networks exist in a certain space. In this case, each coordinator-based wireless network has unique identification information to distinguish it from other coordinator-based wireless networks. The coordinator network is a concept that is distinguished from an infrastructure network that communicates wirelessly through an access point or a base station, and can be considered as a concept included in an ad hoc network, but has one or more coordinators. The coordinator can send the time information needed for the wireless network, and the wireless network devices that have received this information can join the network and send the information to another network device. In the present specification, a description will be made based on 802.15.4, which is one of such coordinator-based wireless networks, but is not limited thereto.

Beacon Frame

The beacon frame announces the existence of the network and plays an important role in maintaining the network. The beacon frame contains parameters required for network devices to join the network. The network coordinator periodically transmits a beacon frame so that devices participating in the wireless network can find and recognize the network.

Probe Request

A probe request frame is a frame that a network device uses to find an area of a network.

Probe Response

Receiving a probe request from the network device, the network coordinator transmits to the device a probe response frame that sets information required for network participation.

-Devices, network devices

A device constituting a wireless network and having a function of communicating with another device. For example, in addition to wireless integrated remote controllers and home appliance controllers, 802.15.4 could be a device for building control, as well as toys, mice, and cooking utensils. The same applies to a device having a communication function in a home network or ubiquitous environment and having a control function and a sensor function as main functions.

Position-aware frame

A location aware frame is a frame that a network device transmits to know its location or to inform another device that wants to find its location. Other devices that receive the location aware frame may know the location of the network device through a location tracking algorithm. The location recognition frame may include an arbitrary transmission time, an identifier of a device to be searched for, an identifier of a device for tracking a location, and the like.

Position measurement frame (position calculation information frame)

The position information measurement frame is a result of calculating the position of the device that has transmitted the position recognition frame by the device receiving the position recognition frame through the transmission time and reception time of the frame, or the reception angle or the intensity of the signal including the frame. It includes. The result of calculating the position may be a difference between the transmission and reception timing of the frame or may be distance information based on the transmission and reception timing. Alternatively, the information may include distance from the device, reception angle, or distance based on a signal waveform.

Location Notification Frame

The position notification frame is a frame including position information obtained by measuring the position of a network device through the information in the position information measurement frame in a specific device that receives the position information measurement frame (position calculation information frame). This frame can be sent to a device that wants to know its location.

Location-aware request frame

A frame that requests to transmit a location recognition frame to know the location of a specific device from the outside. The location aware request frame may be transmitted by a cluster coordinator existing outside the cluster, or may be transmitted by a coordinator inside the cluster. In addition, devices existing in and outside the cluster can transmit. Therefore, their identifier information may also be included in the frame.

1 is a block diagram illustrating a cluster-tree network of 802.15.4 according to an embodiment of the present invention. In 802.15.4, there is a star topology, a peer-to-peer topology, and a cluster-tree network that is a special type of peer.

The star phase has a form similar to 20 of FIG. 1, and has one network coordinator 21. This coordinator communicates with other network devices, and both the full-function device (FFD) and the reduced-function device (RFD) can participate in the star phase. Full-featured devices are devices that have the ability to communicate with other network devices and become network coordinators. The reduced-capacity device can only communicate with the network coordinator, and because it cannot communicate with other devices, it cannot be a network coordinator.

The peer layer topology is the same as 10 in FIG. 1 and has one network coordinator, and each device can communicate with each other. Therefore, the above-described reduction function device does not participate in the peer layer topology.

The cluster tree network is a special type of peer layer topology, and as shown in FIG. 1, a plurality of networks 10, 20, and 30 may be integrated. It is a combination of two or more networks. Each network is called a cluster. There are three clusters 10, 20, 30 in FIG. 1, and the network coordinator of each cluster is 11, 21, 31, respectively. The network coordinator of a cluster is called a cluster header. Among these, a PAN coordinator 31 for coordinating a cluster tree network may be determined, and the PAN coordinator 31 preferably has more computing power and resources than other network devices. The device passing through the network of FIG. 1 may communicate with network devices in the cluster according to the situation.

The situation of getting a position can be divided into two categories. This is a situation where a network device requests location recognition to know where its location is to the PAN coordinator or cluster header, and a situation where the PAN coordinator or cluster header wants to know the location of the network device. The former is called a self location awareness request, and the latter is called a remote location awareness request.

For convenience of description, hereinafter, a network device that wants to know a location is referred to as a tracking device, and a network device that receives information for location tracking from the tracking device is referred to as a reference device.

2 is a flowchart illustrating a process in which a tracking device requests a coordinator to recognize a magnetic location according to an embodiment of the present invention. FIG. 2 shows that the tracking device 101 participating in the cluster requests location recognition to know where its location is, and both the PAN coordinator or the cluster header serves as coordinator. Hereinafter, the PAN coordinator or cluster header is referred to as a coordinator. One cluster is a part of the entire network from the perspective of FIG. 1, but if only one cluster exists, it may be one network itself. In the present specification, the description is based on the most complex cluster-tree network among the various phases of 802.15.4, but may be applied to a star network or an equivalent layer network.

FIG. 2 shows a process in which the tracking device 101 actively participates in a wireless network. The coordinator continuously transmits a beacon frame (S101). However, the tracking device 101 that has not received the beacon frame transmits a probe request frame to inform the network that it participates in the network (S103). The coordinator 31, which finds out that a device participates in the network, transmits a probe response frame including information of the network (S104). The tracking device 101, which has obtained the information necessary for network joining through the received probe response frame, transmits the joining request frame (S107). The coordinator 31 transmits to the tracking device an association response frame in which information necessary for association is set (S108). The tracking device can then communicate with the network. The tracking device coupled to the network transmits a self location recognition request frame to find its location (S115). This frame is received by the reference devices 301, 302 and the coordinator (PAN coordinator or cluster header) in the cluster. Data related to the position of the tracking device can be measured through information such as time information included in the frame and received signal strength (RSS) of the received frame. The reference devices 301 and 302 transmit the measured data to the coordinator (S121), and the coordinator may calculate by performing a location tracking algorithm based on the measured data. When the coordinator transmits a position notification frame including the measured position value to the tracking device 101 (S150), the tracking device 101 knows its position. Thereafter, when the tracking device 101 moves and the location is changed, since the tracking device 101 is already connected to the network, the tracking device 101 may know its own location through the process of S115 to S150. The location tracking algorithm will be described later.

The difference between the reference device and the tracking device is whether or not the location is to be known. Accordingly, in FIG. 2, since the tracking device 101 knows its location, the tracking device 101 may be a reference device, and when another device joins the network, the tracking device 101 may receive location information as a reference device and measure the location of the other device. In addition, even if the reference device, if its position is moved, it is possible to measure the new position through the steps of S115 to S150. That is, the reference device may be a tracking device again. Accordingly, the difference between the reference device and the tracking device may be regarded as a difference between whether the reference device is used to measure the location or the object to be tracked.

3 is a flowchart illustrating a process of requesting a remote location recognition for a tracking device by a coordinator according to another embodiment of the present invention. 3 shows an example of passive scanning in which a network coordinator discovers and sends information to a tracking device. As in FIG. 2, both the PAN coordinator and the cluster header are named coordinators. The newly participating device is also a network device but is named tracking device 102 to distinguish it from other network devices (reference device). The coordinator 11 continuously transmits a beacon frame for maintaining and managing the network (S201). The tracking device that is aware of the existence of the network through this beacon frame transmits a join request frame (S207), and when the coordinator 11 transmits a join response frame to accept the join request (S208), the tracking device 102 ) Can communicate by connecting to the network.

Coordinator 11 is aware of the combination of the tracking device transmits a remote location recognition request frame to know the location of the tracking device (S211). The location recognition request frame is different from the self-detect initiation frame described with reference to FIG. 2. Rather than the device requesting location tracking, a coordinator such as a PAN coordinator or a cluster header requested the location tracking. Thus, privacy can be taken into account so that the tracking device can determine whether to allow location tracking. 3 determines in step S212 whether the device to be tracked accepts the location tracking for the user's privacy. When the tracking device 102 agrees to measure its location, it sends its location information to the coordinator and peripheral devices.

The tracking device 102 transmits a remote location response frame that sets its network identifier, time information, and the like so as to measure its location (S215). The reference devices 401, 402 and the coordinator 11 receiving the frame may determine the location of the tracking device through information such as time information included in the frame and received signal strength (RSS) of the received frame. Measure data associated with The reference devices 401 and 402 transmit this measurement data to the coordinator (S221), and the coordinator may perform a location tracking algorithm based on the measurement data to determine the location of the tracking device.

On the other hand, if the user of the tracking device 102 refuses to measure his / her location in step S212, the tracking device 102 sends a Remote Detect Call Deny Response frame to the coordinator and peripheral devices. Transmit (S216).

The results of location tracking are useful information for network management. Thus, not all devices, but devices that are coordinators, need to know the location information of the devices that make up the network or cluster. Therefore, the PAN coordinator or the cluster header may be able to determine the location of other devices according to the configuration information of the network.

(1) When location information is not announced to both PAN coordinator and cluster header

Since the location information is not notified to both the PAN coordinator and the cluster header, the remote location recognition rejection response frame is transmitted (S216).

(2) When the location information must be forcibly informed only to the PAN coordinator

The PAN coordinator needs to know the device's location because it controls and coordinates the entire network. If the location tracking of the PAN coordinator is allowed for the management of the network, the tracking device cannot send a remote location recognition denied response frame, but sends a remote location aware response frame.

In case of (2), the remote location recognition request frame is unconditionally transmitted regardless of the user's acceptance or rejection response, and the remote location recognition request frame is immediately transmitted without asking the user of the tracking device whether or not to accept or reject the location tracking. It is divided into ways. For ease of use, a remote location-aware response frame can be sent without prompting the user.

On the other hand, if the coordinator that transmitted the remote location recognition request frame is the cluster header, only the PAN coordinator can forcibly obtain the device's location in (2). This is because the cluster constituting the coordinator-based network has a characteristic that exists only for a certain period of time, rather than having a persistent network. Therefore, when the tracking device 102 refuses to announce its location information, the remote location recognition rejection response frame is similarly transmitted to the cluster header 11 and the reference devices 401 and 402 (S216). And there is no further progress.

(3) When the location information is forcibly informed to the PAN coordinator and the cluster header

The tracking device 102 cannot reject the location aware request. The position of the accepting or rejecting device means that the coordinator 11 is known. In this case, for the convenience of the user, the process may proceed to steps S215 and S221 without asking whether the user's location tracking is approved or rejected.

Step S212 of Figure 3 is optional. If the network forcibly enables location recognition between the devices, it proceeds regardless of the acceptance or rejection of the location tracking of the tracking device. If the tracking device forces the acceptance of the nature of the network to measure location, the tracking device may proceed to send a remote location awareness request frame without sending a message asking the user whether to accept or not. In this situation, only steps S201 to S221 exist. On the other hand, although the user depends on whether to accept or reject, even if the user rejects, as shown in the above-described case (3), the location information can be transmitted to the coordinator.

On the other hand, the user may set in advance whether or not the response of the own tracking device for convenience. For example, if the device requesting the location tracking is the coordinator, it can be set to send a remote location awareness response frame unconditionally. You can either allow all devices, or enable location tracking only for the devices that make up your cluster. After the setting, the remote location recognition response frame is transmitted only to the allowed device or coordinator, and the remote location recognition rejection response is transmitted to other devices even without further user intervention.

3 is a configuration for protecting the privacy of the user who is the owner of each device at the time of location tracking. Therefore, according to the configuration of the network step S212 and step S216 may be omitted and proceed.

2 and 3 illustrate the process of participating in the network and the process of finding the location of the tracking device, and do not necessarily follow the process of FIG. 2 in which a device requesting self-location recognition is actively coupled to the network. . Through the passive participation of FIG. 3, once joined to the network, a frame requesting self location recognition may be transmitted again. On the contrary, even after actively participating in the network as shown in FIG. 2, the coordinator may transmit a remote location recognition request frame to know the location of the corresponding tracking device. Meanwhile, the reference device may serve as a relay for receiving frames for measuring the position of the tracking device and transferring the position calculation information obtained through the frame back to the cluster header.

4 is a flowchart illustrating a process of requesting location tracking of a third device by a device other than a PAN coordinator or a cluster header according to an embodiment of the present invention. In addition to FIGS. 2 and 3 described above, additional steps may be required. Since tracking the location of another device can violate the privacy of that device, location tracking requests that occur between the device and the device can be made under the consent of the device being tracked. The device 401 constituting the cluster may request the coordinator (cluster header) 11 to track the location of 102 devices. In this case, the 401 device may request its identifier and the identifier of the device to be searched as information on the frame (S251). The coordinator (cluster header 11) receives the remote location recognition request frame and sends it to the tracking device 102 (S252). The tracking device knows that the 401 device is trying to track its location. It may be shown to the user of the tracking device via a text such as "401 device requests location tracking. Do you want to accept?" If the user sees the text and accepts the location tracking of the device 102 of the device 401, the device transmits a frame (remote location recognition response frame) including time information for the location tracking of the user (S255). The reference devices 401 and 402 and the coordinator 11 that have received the remote position recognition response frame calculate position calculation information based on the information present in the frame and transmit a frame called measurement data to the coordinator (cluster header) 11. (S257). The coordinator 11 transmits the position information of the tracking device 102 to the 401 device with the position calculation information received by the coordinator 11 (S260).

However, if the user refuses to measure his location in step S253, the 102 device transmits a remote location recognition denied response (Detect Call Deny Response) frame (S256). The remote location awareness denied response frame is forwarded to the coordinator 11 and other reference devices 401, 402.

Even in the example of FIG. 4, the user of the tracking device may pre-set the information that the user will accept or reject the remote location aware response frame. You can set in advance whether to accept or reject your own location tracking for a specific device identifier or for all device identifiers. This allows users to maintain their privacy level without having to answer messages about location tracking in the future.

FIG. 5 is a flowchart illustrating a process of tracking a location of a tracking device existing outside a cluster including a PAN coordinator according to another embodiment of the present invention. 5 shows a process of identifying the location of a tracking device present in another cluster that does not include a PAN coordinator. FIG. 5 shows the process by which the PAN coordinator 31 locates the tracking device 102 present in another cluster 10 in the configuration of FIG. 1. 5 includes a case where the PAN coordinator 31 finds the location of the tracking device 102 and another device requests the PAN coordinator 31 for the location of the tracking device 102.

The PAN coordinator transmits a frame requesting remote location recognition to the cluster headers 11 and 21 (S311). The PAN coordinator may send a remote location awareness request frame to track the location of a particular device. In addition, the PAN coordinator may transmit the remote location awareness request frame to the entire network by receiving the location tracking request frame sent by another cluster header. Receiving this frame, the cluster header transmits a frame for requesting the remote location recognition in order to know whether a corresponding tracking device exists in its cluster (S312). Steps S311 and S312 may contain the same contents or different contents depending on the implementation of the frame. There is a difference that the frame of step S311 is received by the cluster header 11 and transmitted to the network devices constituting its own cluster in step S312. Receiving the remote location recognition request frame, the tracking device determines whether to accept or reject tracking its location (S314).

If it allows to track its location, it sends a remote recognition response frame containing information for indicating its location to the reference device (401, 402) and the cluster header (11) (S315). The reference device transmits the data measured through the information included in the received remote recognition response frame to the cluster header 11 (S321). The cluster header 11 knows the location of the tracking device through the collected data and transmits a location notification frame to the PAN coordinator (S331).

When a PAN coordinator outside the cluster makes a remote location awareness request to know the location of the device, the user of the tracking device can proceed without asking the user whether to accept or reject the location. This process is described in FIG. Depending on the configuration of the network, if the PAN coordinator can measure the location of all devices, the user of the tracking device can send a remote location aware response frame without having to accept or reject the location tracking. . And even if there is a user's accept / reject response, the remote location aware response frame may be transmitted to the PAN coordinator.

On the other hand, when a third device tracks its location through the PAN coordinator, or when the PAN coordinator does not enforce the location tracking of another device according to the configuration of the network, the user of the tracking device may You may not agree. The tracking device 102 transmits the remote location recognition rejection response frame to the cluster header 11 managing the cluster including the reference devices 301 and 302 and the tracking device (S316). The cluster header transmits the received remote location recognition rejection response frame to the PAN coordinator (S317), and the PAN coordinator learns that the location of the tracking device cannot be measured. If the other device requests the location tracking of the tracking device, the device transmits a remote location recognition reject response frame to inform the corresponding device that the location tracking has been rejected.

6 is a flowchart illustrating a process of tracking a location of a tracking device existing outside of a relay device according to another embodiment of the present invention. The information sent by the PAN coordinator in the remote location awareness request may be transmitted directly to the cluster header and may be transmitted through another cluster header. Therefore, the cluster header, which transmits and receives a frame requesting the location tracking and a frame including the location tracking result information, becomes a relay device.

In FIG. 6, the PAN coordinator transmits a remote location recognition request frame to the cluster header 51 (S411). The cluster header 51 transmits the remote location recognition request frame back to the third cluster header 11 (S412), and the cluster header 11 performs location tracking on the devices existing in its cluster. Herein, the case where the tracking device accepts and rejects the location tracking before the location tracking has been performed in different ways has been described with reference to the examples of FIGS. 2 to 5 described above.

When the tracking device accepts its own location tracking, when the cluster header 11 performs location tracking as a result of the location tracking operation, the location tracking frame is transmitted to the cluster header 51 that has transmitted the location tracking request frame to itself (S431). . The cluster header 51 transmits the location notification frame back to the PAN coordinator (S432).

On the other hand, when the tracking device refuses to measure its own location, the tracking device transmits a remote location recognition rejection response frame (S434). Upon receiving this, the relay device 51 also sends a remote location recognition rejection response frame to the PAN coordinator 31 (S436).

There are several algorithms that can be used to measure the position in FIGS.

7 is a conceptual diagram illustrating location tracking through a TOA scheme according to an embodiment of the present invention. Time of Arrival (TOA) is a method of obtaining a distance by measuring a signal transmission time between the tracking device 101 and other network devices 11, 301, and 302. The propagation time of the radio wave can be obtained through the difference between the transmission time of a frame (Self Detect Initiation, Detect Call Response) sent to inform the position and the time received by the network devices. By calculating this difference and the propagation speed of the signal transmitting the frame, a circle centered on the network devices 11, 301 and 302 can be obtained. In order to use this method, at least three reference devices must exist. If three or more reference devices send the measured values, the coordinator 11 may select and calculate three pieces of data determined to be the most accurate values among them. In one embodiment, the correct signal may be determined by the received signal strength (RSS) of the signal. For example, if the received signal strength is shown in Table 1, the position of the tracking device may be calculated based on the measurement data of the three strongest signals 11, 301, and 302. In Table 1 below, the 307 device is excluded because it is difficult to guarantee the accuracy of the data because the signal reception strength is weak.

device RSS Measurement data (m) 11 70 15 301 80 10 302 90 8 307 30 10

However, the reception strength of the signal is exemplary, and it is also possible to determine the reference device according to the distortion of the signal or other characteristics of the signal.

8 is a block diagram showing location tracking through the TDOA method according to an embodiment of the present invention. TDOA (Time Difference of Arrival) is a method of determining the position by measuring the relative difference of the time of arrival of radio waves from two signal sources. A forward link method consisting of multiple signal sources and one receiver and one signal source And a reverse link scheme consisting of a plurality of receivers. The basic principle of TDOA is that the propagation time difference, which is proportional to the difference in distance from two sources to the receiver, is measured, and the receiver is located on a hyperbolic curve that focuses on the two sources. At this time, each base station must be synchronized, and time synchronization between base stations is performed by using a satellite clock. Two hyperbolas are obtained from three signal sources and the intersection of the two curves is the receiver position.

8 is a diagram illustrating a process of applying TDOA in 802.15.4. Here, the intersection of the hyperbola obtained from the 11 and 301 network devices and the hyperbola obtained from the 11 and 302 network devices becomes the position of the tracking device 101. The data transmitted by the reference network device 301, 302 to the coordinator 11 to find the intersection of the hyperbola is equal to the TOA. When several data are received, the coordinator 11 may select and calculate the measurement data through RSS as shown in Table 1.

In addition to FIGS. 7 and 8, AOA (Angle of Arrival) and RF Fingerprinter (Radio Frequency Finger Printer) schemes may also be used. AOA measures the angle of arrival (incidence angle) of the frame signal sent from the tracking device to find the position of the signal coming from the tracking device with respect to the network device. It is a method of identifying the direction through an angle, that is, where the cell site (cover area) and the signal source overlap with the location. In this embodiment also, RSS can be calculated based on values measured from several network devices with the strongest signal.

In order to obtain the characteristic value of the frame transmitted by the tracking device, the RF fingerprint printer snapshots the received signal instantly and analyzes the transmitted signal of the snapshot receiver to extract the unique characteristic of the received signal. ) Is a positioning method that compares this signal with an existing database and measures the position of the receiver.

The position measurement algorithm described herein is merely an example algorithm.

9 is a frame format of the MAC layer for implementing a location tracking function in 802.15.4 according to an embodiment of the present invention. FIG. 9 is an embodiment using an algorithm for measuring a position based on a difference between a transmission time and a reception time of a frame, and may vary according to a location tracking method.

The structure of the command frame of 802.15.4 is equal to 700. Frame Control is 16 bits long and contains information defining the type of frame, address field, and other control flags. The sequence number indicates a unique sequence identifier for the frame. Address fields are variable. In the command field, a PAN identifier / address field of a receiver and a PAN identifier / address field of a transmitter are included. The instruction frame identifier indicates which instruction to perform and has a value shown in the table of 720. 0xff to 0xff are reserved and can be defined for future use. Thus instructions for location tracking can be defined using these reserved parts.

The command payload includes parameters required for executing a command and may be defined as shown in 710.

When the tracking device wants to know where its location is, the Self Detect Initiation frame 711 that it sends has a command identifier of 0x21. As an instruction parameter, an identifier of a transmitting tracking device and a frame transmission time may be recorded. Other reference devices (including coordinators) that have received the frame can measure the distance through the transmission time in the frame and the reception time of the frame. This measured distance or data is sent to the coordinator to calculate the location of the tracking device that requested location recognition.

The calculated result is transmitted through a Self Detect Result frame 712, which has an instruction identifier of 0x22. Command parameters include the tracking device ID and location information.

Next, when the coordinator wants to know the location of a specific network device, the Detect Call Request frame 713 and the Detect Call Response frame 714 used to deny location tracking are used. In this case, the configuration of the transmitting Detect Call Deny Response frame 717 will be described. The remote location recognition request frame 713 is used to find the location of the tracking device existing in its network and to locate the reference device not present in its network. The command parameter contains the identifier of the network device to find. The tracking device receiving the frame transmits a Remote Detect Call Response frame 714 to inform its location. The command parameters included herein may be a tracking device identifier and a transmission time, such as a Self Detect Initiation frame 711. On the other hand, if the tracking device refuses to indicate its own location, the device transmits a Detect Call Deny Response frame 717. The command parameter included here may be a tracking device identifier.

The Self Detect Initiation frame 711 and the Remote Detect Call Response frame 714 contain basic data for position measurement. When using TOA or TDOA, it may be a transmission time, and when using an RF fingerprint printer, information related to signal strength may be used. This information can be aggregated to yield data for tracking the location of the tracking device that transmitted the frames. The Positioning Data frame 715 performs the function of transmitting this calculated data to the coordinator. The calculation data may be time difference information obtained through a transmission time point and a reception time point of the frame, and may be distance information obtained through the time difference information. It may also be information in which the incident angle and the distance information of the signal are integrated. The command parameters may include data calculated from the information included in the magnetic location recognition request frame 711 and the remote location recognition response frame 714, the signal strength (RSS), the location of the reference device that calculated the data, and the like. Can be. Signal strength (RSS) is used to extract the most reliable data when several network devices transmit calculated data. Therefore, in addition to the signal strength, it may vary depending on the algorithm used for location tracking. In addition, the position information of the reference device that has been measured is required because the calculated data is a relative value with respect to the position of the reference device. If the coordinator of the network stores the location of all network devices present in its network, it is not necessary to transmit the location of the reference device and may vary depending on the coordinator's implementation.

The location result (Detect Result) frame 716 is used when a PAN coordinator requesting the location tracking of a specific network device exists in a different PAN from the network device, and the cluster header combined with the network device transmits the location information to the PAN coordinator. do. The cluster header sends command parameters and command frames containing the PAN identifier, the identifier of the tracking device, and location information to the PAN coordinator.

The instructions are an embodiment of implementing the location recognition, location notification, location recognition request and location information measurement frame used in the claims of the present specification. The magnetic location recognition request frame 711 and the remote location recognition response frame 714 are examples of location recognition frames, and the location notification frames 712 and 716 are examples of location notification frames. The remote location recognition request frame 713 is an example of a location recognition request frame, and the measurement data frame 715 is an example of a location information measurement frame.

The device identifier shown in the command, for example, the device identifier defined in the remote location recognition request frame 713 may include a plurality of information of the identifier in various ways. That is, it may include an identifier of a device to be measured for location and an identifier of a device to know the location of the device. In addition, when finding a device in another cluster, the identifier information of the corresponding cluster must be included in addition to the identifier of the device.

10 is a block diagram illustrating command parameters of a frame according to an embodiment of the present invention.

(a) shows that the identifier information in the parameter of the remote location recognition request frame is variously configured according to each situation. In the case of FIG. 3, since the cluster header finds a location of a specific device, a frame 7131 in which only an identifier of the corresponding device is defined is possible. In the case of FIG. 4, since the other device finds the location of the tracking device, a frame 7122 including an identifier of the device requesting the location tracking and an identifier of the tracking device, that is, the location tracking device is possible. 5 and 6 are cases for tracking the location of a device existing in another cluster, a frame 7133 including an identifier, a cluster identifier, and an identifier of a device to be tracked is possible. You can put a check flag on the instruction frame to distinguish each frame.

(b) shows that the identifier information in the parameters of the remote location recognition response frame varies according to each situation. As in (a), in the case of FIG. 3, a frame 771 including an identifier and a transmission time of a device to be found is possible. In the case of FIG. 4, since the other device finds the location of the tracking device, a frame 7142 including an identifier of the device requesting the location tracking, an identifier of the tracking device, that is, a location tracking target device, and a transmission time is possible. 5 and 6 are cases for tracking the location of a device existing in another cluster. Therefore, a frame 7143 including an identifier and a cluster identifier of a device for which location tracking is requested, an identifier of a device to be tracked, and a transmission time is provided. It is possible. You can put a check flag on the instruction frame to distinguish each frame.

(c) shows that the identifier information in the parameters of the remote location recognition rejection response frame is configured variously in each situation. Use 0x27 to indicate a remote location recognition reject response frame. It is similar to the configuration of the remote location recognition response frame described in (b) but does not include information related to location tracking such as transmission time since location tracking is rejected. The remote location recognition denied response frame is a frame indicating that the tracking device rejects the location tracking. 3 includes an identifier 7151 of the tracking target device that has refused location recognition. As illustrated in FIG. 4, 7152 is a structure of a frame transmitted when the tracking device rejects the location tracking when another device in the cluster requests the location tracking. It includes the device identifier requesting the location tracking and the identifier of the tracking target device that rejected it. The 7153 frame is a frame transmitted when a device of another cluster tries to track a location. It includes the identifier of the cluster that requested the location tracking, the identifier of the device, and the identifier of the device to be tracked.

Those skilled in the art will appreciate that the present invention can be embodied in other specific forms without changing the technical spirit or essential features of the present invention. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is indicated by the scope of the following claims rather than the detailed description, and all changes or modifications derived from the meaning and scope of the claims and the equivalent concept are included in the scope of the present invention. Should be interpreted.

 The implementation of the present invention allows the location of devices to be tracked even in wireless networks based on coordinators.

In particular, it provides a protocol for location tracking in 802.15.4a environment using UWB.

Claims (51)

Transmitting a first frame including its identifier and time information to the wireless network by a device combined with the wireless network to know its location information; And And receiving, by the device, a second frame containing location information of the device transmitted from the wireless network in response to the first frame. The method of claim 1, The wireless network is a location tracking method in a coordinator-based wireless network using a protocol of 802.15.4. The method of claim 1, And the time information is a transmission time of the first frame. The method of claim 1, And wherein the identifier of the device is a MAC address of the device. The method of claim 1, The device makes a probe request for confirming the existence of a wireless network, receives a probe response from the wireless network, confirms the existence of the wireless network, makes a join request to the wireless network, and receives a join response from the wireless network. A location tracking method in a coordinator-based wireless network that is a device combined with a wireless network. The method of claim 1, In the coordinator-based wireless network, the device receives a beacon from the wireless network and confirms the existence of the wireless network. Then, the device makes a join request to the wireless network and receives a join response from the wireless network. Location tracking method. Transmitting, by the first device in association with the wireless network, a first frame including an identifier of the first device and the second device to the wireless network to know the location information of the second device; And And receiving, by the first device, a second frame comprising location information of the second device transmitted from the wireless network in response to the first frame. The method of claim 7, wherein The wireless network is a location tracking method in a coordinator-based wireless network using a protocol of 802.15.4. The method of claim 7, wherein And wherein the identifiers of the first and second devices are MAC addresses of the first and second devices, respectively. The method of claim 7, wherein After the first device makes a probe request for confirming the existence of a wireless network and receives a probe response from the wireless network to confirm the existence of the wireless network, the first device makes a join request to the wireless network and receives a join response from the wireless network. Location tracking method in a coordinator-based wireless network that is a device combined with the wireless network. The method of claim 7, wherein After the first device receives the beacon from the wireless network and confirms the existence of the wireless network, the first device is a device that combines with the wireless network by making a join request to the wireless network and receiving a join response from the wireless network. How to track your location on the network. Receiving, by the second device, a first frame including an identifier of the first device and an identifier of the second device that requested location tracking of the second device from the wireless network; And Transmitting, by the second device in response to the first frame, a second frame including an identifier of the first device, an identifier of the second device, and time information to the wireless network. How to track your location. The method of claim 12, The wireless network is a location tracking method in a coordinator-based wireless network using a protocol of 802.15.4. The method of claim 12, And wherein the identifiers of the first and second devices are MAC addresses of the first and second devices, respectively. The method of claim 12, And the time information is a transmission time of the second frame. Receiving, by the second device, a first frame including an identifier of the first device and an identifier of the second device that requested location tracking of the second device from the wireless network; Determining whether to accept or reject location tracking; And When the determination result indicates that the position tracking is approved, the second device transmits a second frame including the identifier of the first device, the identifier of the second device, and time information to the wireless network in response to the first frame. A location tracking method in a coordinator based wireless network comprising the step of: The method of claim 16, The determining may include determining the input value corresponding to the acceptance or rejection selected by the user of the second device. The method of claim 16, The determining of the location tracking method in the coordinator-based wireless network comprising the step of comparing the identifier of the first device and the value preset in the second device. The method of claim 16, If the determination result does not accept the position tracking, And wherein the second frame comprises an identifier of the first device and an identifier of the second device. The method of claim 16, The wireless network is a location tracking method in a coordinator-based wireless network using a protocol of 802.15.4. The method of claim 16, And wherein the identifiers of the first and second devices are MAC addresses of the first and second devices, respectively. Receiving a first frame including an identifier and time information of the device transmitted from another device; Obtaining location calculation information used to calculate the location of the device using the time information; And Transmitting to the network coordinator a second frame comprising an identifier of the device and the location information. The method of claim 22, The wireless network is a location tracking method in a coordinator-based wireless network using a protocol of 802.15.4. The method of claim 22, And the time information is a transmission time of the first frame. The method of claim 24, And the location calculation information is a difference between a reception time of the first frame and a transmission time of the first frame. The method of claim 22, And the device identifier is a MAC address of the device. Receiving a first frame including an identifier of a first device requesting location tracking of the second device transmitted by a second device, and an identifier and time information of the second device; Obtaining location calculation information used to calculate the location of the second device using the time information; And And transmitting to the network coordinator a second frame comprising an identifier of the first device, an identifier of the second device, and the location information. The method of claim 27, The wireless network is a location tracking method in a coordinator-based wireless network using a protocol of 802.15.4. The method of claim 27, And the time information is a transmission time of the first frame. The method of claim 29, And the location calculation information is a difference between a reception time of the first frame and a transmission time of the first frame. Receiving from the network a plurality of frames including an identifier of the device and location information of the device; Calculating a location of the device using the location information; And And transmitting the frame including the calculated position information to the device. The method of claim 31, wherein The wireless network is a location tracking method in a coordinator-based wireless network using a protocol of 802.15.4. The method of claim 31, wherein And the device identifier is a MAC address of the device. Receiving from the network a plurality of frames including an identifier of the first device that requested location tracking of the second device and an identifier and location information of the second device; Calculating a location of the second device using the location information; And Transmitting a frame including the calculated location information to the first device. The method of claim 34, The wireless network is a location tracking method in a coordinator-based wireless network using a protocol of 802.15.4. The method of claim 34, And wherein the identifiers of the first and second devices are MAC addresses of the first and second devices, respectively. Receiving from the network a first frame comprising an identifier of the first device that requested location tracking of the second device and an identifier of the second device; Sending the first frame to a second device in the network; Receiving a second frame from the second device indicating that the location tracking is to be rejected; And Transmitting the second frame to the first device. The method of claim 37, wherein The wireless network is a location tracking method in a coordinator-based wireless network using a protocol of 802.15.4. The method of claim 37, wherein And wherein the identifiers of the first and second devices are MAC addresses of the first and second devices, respectively. Receiving, by the coordinator of the first wireless network, a first frame comprising an identifier of the first device and an identifier of the second device sent by the first device for location tracking of the second device; Transmitting, by the coordinator of the first wireless network, the coordinator of the second wireless network a second frame including the first wireless network identifier, the first device identifier, and the identifier of the second device; A third including the first wireless network identifier, the first device identifier, the identifier of the second device, and location information of the second device, transmitted by the coordinator of the second wireless network in response to the second frame; Receiving a frame by a coordinator of the first wireless network; And Transmitting, by the coordinator of the first wireless network, a fourth frame containing location information of the second device to the first device. The method of claim 40, Wherein said first and second wireless networks use a protocol of 802.15.4. The method of claim 40, And wherein the identifiers of the first and second devices are MAC addresses of the first and second devices, respectively. Receiving, by the coordinator of the first wireless network, a first frame comprising an identifier of the first device and an identifier of the second device sent by the first device for location tracking of the second device; Transmitting, by the coordinator of the first wireless network, the coordinator of the second wireless network a second frame including the first wireless network identifier, the first device identifier, and the identifier of the second device; When the second device receiving the second frame rejects the location tracking, the second device including the first wireless network identifier, the identifier of the first device, and the identifier of the second device in response to the second frame. Receiving, by the coordinator of the first wireless network, three frames; And And transmitting, by the coordinator of the first wireless network, a fourth frame to the first device, the fourth frame comprising information that the second device refuses to track the location. The method of claim 43, Wherein said first and second wireless networks use a protocol of 802.15.4. The method of claim 43, And wherein the identifiers of the first and second devices are MAC addresses of the first and second devices, respectively. The coordinator of the second wireless network receives a first frame including a first wireless network identifier transmitted by the coordinator of the first wireless network, an identifier of the first device requesting location tracking of the second device, and an identifier of the second device. Doing; Sending, by the coordinator of the second wireless network, a second frame including the first wireless network identifier, the identifier of the first device, and the identifier of the second device to the second device coupled with the second wireless network; A plurality of third frames including the first wireless network identifier, the identifier of the first device, the identifier of the second device and the location information of the second device from the second wireless network; Receiving by the coordinator of the; Calculating, by the coordinator of the second network, the location of the second device using the location information of the second device; And The second network coordinator sends a fourth frame to the first wireless network coordinator including the first wireless network identifier, the first device identifier, the identifier of the second device, and the calculated location information of the second device. A location tracking method in a coordinator based wireless network comprising the step of: The method of claim 46, Wherein said first and second wireless networks use a protocol of 802.15.4. The method of claim 46, And wherein the identifiers of the first and second devices are MAC addresses of the first and second devices, respectively. Receiving a first frame comprising a first wireless network identifier sent by the coordinator of the first wireless network, an identifier of the first device requesting location tracking of the second device, and an identifier of the second device; Sending, by the coordinator of the second wireless network, a second frame to the third wireless network coordinator comprising the first wireless network identifier, the identifier of the first device, and the identifier of the second device; A second frame including a third frame including the first wireless network identifier transmitted by the third wireless network, an identifier of the first device, an identifier of the second device, and calculated position information of the second device; Receiving by the coordinator of the; And The second wireless network coordinator sends a fourth frame to the first wireless network coordinator including the first wireless network identifier, the first device identifier, the identifier of the second device, and the calculated location information of the second device. A location tracking method in a coordinator based wireless network comprising the step of transmitting. The method of claim 49, And said first, second, and third wireless networks use a protocol of 802.15.4. The method of claim 49, And wherein the identifiers of the first and second devices are MAC addresses of the first and second devices, respectively.

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