CN1728668A - Based on the location tracking method in the wireless network of telegon - Google Patents

Abstract

A location tracking method in a coordinator-based wireless network is provided. The location tracking method in a coordinator-based wireless network includes: sending, by a device connected to the wireless network, a first frame including its own identifier and time information to the wireless network to disclose its location information; and by said The device receives, as a response to the first frame, a second frame including location information of the device transmitted from the wireless network.

Description

Location Tracking Method in Coordinator-Based Wireless Network

Technical field

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

Background technique

A recent trend in networking is to interconnect devices other than computers that need to exchange data. In the past, wired networking was the standard. However, the disadvantages of wired networking, such as wiring structure and limited mobility, make wireless communication technology necessary. Wireless Local Area Network (WLAN) and Wireless Personal Area Network (WPAN) standards are under development. WPAN has a range of 10m, while WLAN has a range of 50m to 100m. Since WPAN consumes less energy and supports Ad-hoc networks, it is more suitable for electronic home appliances in terms of mobility and range.

A coordinator-based wireless network uses the coordinator to manage the communication time and contention mode of the wireless network. It uses a number of protocols determined by the IEEE 802.15 working group created to create the WPAN standard. The IEEE 802.15 working group is divided into four task groups. TG 1 works on the standard of WPAN based on Bluetooth (Bluetooth) 1.x. TG 2 studies the coexistence of wireless networks. TG 3 researches ultra-wideband (UWB) that provides a high transfer rate of 20Mbps or more at low power consumption. TG 4 studies low-speed WPAN (LR-WPAN), a technology that provides low transmission rates (maximum 250kpbs) at low power consumption.

LR WPAN involves low-cost communication networks that require low data transfer rates. The IEEE 802.15.4 standard, known as "ZigBee," is a wireless transmission technology for networks of low-cost, low-power devices such as wireless integrated remote controls, home appliance controllers, building management controllers, and toys. The ZigBee group was established in July 2000, and since then it has completed work on standards for the physical layer and MAC.

The standard specifies transmission at 250kbps (16 channels in the 2.4GHz band) or 40kbps/20kbps (10 channels in the 915MHz band or 1 channel in the 868MHz band) with a range of 1m to 100m.

Work is still ongoing on the upper layers, including the network layer. Fifty companies, including Philips, Motorola, Honeywell, Mitsubishi, Invensys and Samsung, are sponsors of the ZigBee Alliance, which complements the existing standard by adding ad-hoc wireless networking and networking protocols for distributed devices.

ZigBee does the work of preparing the checklist and clearly defining the applications that will actually perform interoperability testing. The requirements of IEEE 802.15.4 include low power consumption, low cost, and simple infrastructure. These requirements are necessary for networked sensors and control devices.

IEEE 802.15.4a defines a standard for a low-speed location-based network using Ultra-Wideband (UWB), which is a new networking technology that realizes precise location awareness services that enable ubiquitous environments.

IEEE 802.15.4a is a subgroup of 802.15.4, and it uses the same medium access control (MAC) as 802.15.4, but replaces the physical layer (PHY) with UWB. However, it does not define a location tracking protocol. Therefore, location-based services must be added to coordinator-based wireless networks to embody IEEE 802.15.4a location tracking techniques. Privacy protection services should also be added in a way that allows users to control location tracking.

Contents of the invention

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

Another aspect of the present invention is to track a location of a device based on a wireless communication technology such as UWB by using a location tracking function of a coordinator-based wireless network.

Aspects of the present invention are not limited to the above-mentioned aspects and other aspects not mentioned will become more apparent to those of ordinary skill in the art from the following description.

The present invention provides a location tracking method in a coordinator-based wireless network. A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: sending, by a device connected to the wireless network, a first frame including an identifier and time information to the wireless network to disclose the device and receiving a response frame including the location information of the device transmitted from the wireless network.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: transmitting a first frame including identifiers of a first device and a second device to a wireless network so as to connect to the wireless network. The first device knows the location of the second device; and a response frame including the location information of the second device transmitted from the wireless network is received by the first device.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: receiving, by a second device, an identifier of the first device requesting location tracking of the second device and a second device from the wireless network. a first frame of the device's identifier; and sending, by the second device, a second frame including the first device's identifier, the second device's identifier, and time information to the wireless network in response to the first frame.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: receiving, by a second device, an identifier including an identifier of a first device requesting location tracking of the second device from the wireless network, and a second device. A first frame of the identifier of the second device; determine whether location tracking is allowed; and if location tracking is allowed, the second device sends a second frame including the identifier of the first device, the identifier of the second device, and time information to Wireless network, in response to the first frame.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: receiving a first frame transmitted by a device including an identifier of the device and time information; using the time information to obtain an calculating location calculation information of a location of the device; and transmitting a second frame including an identifier of the device and the location calculation information to a network coordinator.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: receiving an identifier of a first device that requests location tracking of the second device from a second device, and the second device the first frame of the identifier of the second device and time information; obtain position calculation information for calculating the position of the second device using the time information; and will include the identifier of the first device, the identifier of the second device, and the position calculation information The second frame is sent to the network coordinator.

A position tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: receiving a plurality of frames from the network including an identifier of a device and position calculation information of the device; using the position calculation computing a location of the device; and transmitting a frame including the location information to the device.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes receiving an identifier from the network including an identifier of a first device requesting location tracking of a second device, an identifier of a second device, and a plurality of frames of position calculation information; calculate a position of the second device using the position calculation information; and transmit the frame including the position of the second device to the first device.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes receiving a message from the network including an identifier of a first device requesting location tracking of a second device and an identifier of a second device. a first frame; sending the first frame to a second device of the network; receiving a second frame for announcing that location tracking has been rejected from the second device; and sending the second frame to the first frame a device.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: receiving a first frame including an identifier of the first device and an identifier of the second device transmitted by the first device, so that The coordinator of the first wireless network may track the second device; the coordinator of the first wireless network will include the identifier of the first wireless network, the identifier of the first device, and the a second frame of the identifier is sent to the coordinator of the second wireless network; receiving by the coordinator of the first wireless network the identifier sent by the coordinator of the second wireless network comprising the identifier of the first wireless network, a third frame of the identifier of the first device, the identifier of the second device, and location information of the second device in response to the second frame; and by the first wireless network The coordinator transmits a fourth frame including location information of the second device to the first device.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: receiving a first frame including an identifier of the first device and an identifier of the second device transmitted by the first device, so that The coordinator of the first wireless network may track the second device; the coordinator of the first wireless network will include the first wireless network's identifier, the first device's identifier, and the second The identifier of the device is sent to the coordinator of the second wireless network; if the second device, having received the second frame, rejects location tracking, the coordinator of the first wireless network receives the a third frame of the identifier of the network, the identifier of the first device, and the identifier of the second device, as a response to the second frame; and the coordinator of the first wireless network will include the first A fourth frame of information that the second device rejects position tracking is sent to the first device.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: receiving, by the coordinator of the second wireless network, an identifier including the identifier of the first wireless network sent by the coordinator of the first wireless network , the identifier of the first device requesting location tracking of the second device, and the first frame of the identifier of the second device; the coordinator of the second wireless network will include the identifier of the first wireless network, the The identifier of the first device and the identifier of the second device are sent to the second device connected to the second wireless network; the coordinator of the second wireless network receives the information from the second wireless network including the first wireless an identifier of the network, an identifier of the first device, an identifier of the second device, and a plurality of third frames of position calculation information of the second device; used by the coordinator of the second wireless network using the second the location calculation information of the device to calculate the location of the second device; and by the coordinator of the second wireless network will include the identifier of the first wireless network, the identifier of the first device, the second A fourth frame of the identifier of the device and the calculated location information of the second device is sent to the coordinator of the first wireless network.

A location tracking method in a coordinator-based wireless network according to an exemplary embodiment of the present invention includes: receiving an identifier including the first wireless network transmitted by the coordinator of the first wireless network, requesting location tracking of the second device The first frame of the identifier of the first device, and the identifier of the second device; the coordinator of the second wireless network will include the identifier of the first wireless network, the identifier of the first device, and the The second frame of the identifier of the second device is sent to the coordinator of the third wireless network; the coordinator of the second wireless network receives the identification of the first wireless network sent by the third wireless network identifier, the identifier of the first device, the identifier of the second device, and the location information of the second device; and the coordinator of the second wireless network will include the first A fourth frame of the identifier of the wireless network, the identifier of the first device, the identifier of the second device, and location information of the second device is transmitted to the coordinator of the first wireless network.

Description of drawings

The above and other aspects of the present invention will become more apparent from a detailed description of exemplary embodiments thereof, taken in conjunction with the accompanying drawings, in which:

Fig. 1 shows the structure of the cluster tree-like (cluster-tree) network of 802.15.4 according to an exemplary embodiment of the present invention;

2 is a flow chart showing a process in which a tracked device requests self location awareness from a coordinator according to an exemplary embodiment of the present invention;

3 is a flow chart illustrating a process in which a coordinator requests remote location awareness (remote location awareness) from a tracked device according to an exemplary embodiment of the present invention;

4 is a flowchart illustrating a process in which a device other than a PAN coordinator or a cluster head requests location tracking of other devices according to an exemplary embodiment of the present invention;

5 is a flowchart illustrating a process for tracking a location of a tracked device existing outside a cluster in which a PAN coordinator exists, according to an exemplary embodiment of the present invention;

6 is a flowchart illustrating a process for tracking the location of a tracked device using a relay device according to an exemplary embodiment of the present invention;

FIG. 7 is a conceptual diagram illustrating location tracking by a TOA method according to an exemplary embodiment of the present invention;

FIG. 8 shows the structure of location tracking by the TDOA method according to an exemplary embodiment of the present invention;

FIG. 9 shows a frame format of a MAC layer for embodying a location tracking function in 802.15.4 according to an exemplary embodiment of the present invention; and

10, 11, 12 are block diagrams illustrating command payloads of frames according to exemplary embodiments of the present invention.

Detailed ways

Terms used in this specification will be described below.

Coordinator-based Wireless Network

A network including a wireless network device serving as a coordinator (hereinafter referred to as a coordinator-based wireless network) forms a single independent wireless network based on the coordinator. If multiple coordinator-based wireless networks exist in the same area, each coordinator-based wireless network has a unique identifier to distinguish it. A coordinator-based network is different from an infrastructure network for performing wireless communication through an access point or a base station, and it may include a plurality of coordinators and is included in an ad-hoc network. The coordinator can send the time information required by the wireless network, and the wireless network device receiving this information can send it to other network devices. In this specification, an IEEE 802.15.4 coordinator-based wireless network will be described, but this is only an exemplary embodiment of the present invention and the present invention is not limited thereto.

Beacon Frame

The beacon frame announces the existence of the network and it also performs an important role in the maintenance of the network. A beacon frame includes a payload required when a network device connects to the network. The network coordinator periodically sends beacon frames so that devices participating in the wireless network can identify the network.

Probe Request

A network device sends a probe request frame to find a network.

Probe Response

The network coordinator receiving the probe request from the network device transmits a probe response frame setting information required when the device is connected to the network.

device, network device

A device is a component of a wireless network that can communicate with other devices. For example, in IEEE 802.15.4, there are building management controllers, toys, mice, and cookers in addition to wireless integrated remote controls and electronic home appliance controllers. Also included are devices having communication functions, control functions, and sensor functions in a home network or ubiquitous environment.

location recognition frame

Location Awareness Frames allow both network devices and other devices to know their location. Other devices receiving the location identification frame can know the location of the network device through location tracking algorithms. The location recognition frame may include a transmission time of the frame, an identifier of a search device, and an identifier of a device that is a subject of location tracking.

Position information positioning frame (position calculation information frame)

The location information frame includes the location of the device calculated using the frame transmission time and the frame reception time, the angle of the received signal including the frame, or the strength of the received signal. The position can be expressed as a time difference; that is, the difference between the time the frame was sent and the time the frame was received.

position result frame

The position result frame includes position information obtained by a specific device receiving the position information frame (position calculation information frame). This frame can be sent to devices that want to know their location.

Location Identification Request Frame

The purpose of the location recognition request frame is to request the transmission of the location recognition frame so that devices located outside the cluster can know the location of a specific device. The location recognition request frame may be sent by a cluster coordinator located outside the cluster or a coordinator located inside the cluster. Additionally, the location identification request frame may be sent by a device located inside or outside the cluster, which device may insert its identifier into the frame.

FIG. 1 shows the structure of an 802.15.4 cluster tree network according to an exemplary embodiment of the present invention. 802.15.4 includes star, peer-to-peer, and cluster-tree topologies as variations of peer-to-peer topologies.

The star topology is shown by reference numeral 20 in FIG. 1 and has one network coordinator 21 . Communication between network devices is performed through this coordinator, and full function devices (FFDs) as well as reduced function devices (RFDs) can participate in a star topology. A full-featured device can communicate with other network devices and can act as a network coordinator. Reduced function devices can only communicate through the network coordinator. Since a reduced function device cannot independently communicate with other devices, it cannot become a network coordinator.

Reference number 10 of Figure 1 shows a peer-to-peer topology with one network coordinator. Devices can communicate with other devices in this type of network. The above described reduced function devices cannot participate in peer-to-peer networks.

A cluster tree network is a variant of peer-to-peer topology and it can integrate several networks (eg 10, 20 and 30). It is composed by connecting at least two networks. Each network is called a cluster. In Figure 1 there are three clusters 10, 20 and 30, and the network coordinators of these clusters are labeled 11, 21 and 31 respectively. The network coordinator of the cluster is called the cluster head. A coordinator 31 as a PAN coordinator may be determined among a plurality of network coordinators to coordinate the cluster tree network. Preferably, the PAN coordinator 31 has more computing power and resources than other network devices. Devices through the network of FIG. 1 may communicate with network devices in corresponding clusters.

Position recognition can be mainly divided into two cases. In the first case, a network device requests location identification from the PAN coordinator or cluster head to know its location. In another case, the PAN coordinator or cluster head requests the location of the network device. The former is called a self-location identification request, and the latter is called a remote location identification request.

For convenience of explanation, hereinafter, a network device whose location is tracked is referred to as a tracked device, and a network device receiving location tracking information from the tracked device is referred to as a reference device.

FIG. 2 is a flowchart illustrating a process in which a tracked device requests self-location recognition from a coordinator according to an exemplary embodiment of the present invention. In FIG. 2, the tracked device 101 participating in the cluster requests location identification to know its location, and the PAN coordinator or the cluster head acts as the coordinator. A cluster is part of the network in Figure 1, but if there is only one cluster, it could be the entire network. Among the various topologies of IEEE 802.15.4, a cluster tree network (the most complex topology) is shown in this specification, but a star or peer-to-peer topology can also be applied.

Figure 2 shows the active scanning process. The coordinator 31 continuously transmits beacon frames (S101). However, the tracked device 101 that has not received the beacon frame transmits a probe request frame to announce that it wants to participate in the network (S103). The coordinator 31 knows that a device wants to participate in the network and transmits a probe response frame including network information (S104). The tracked device 101 obtains information required for network connection through the received probe response frame, and transmits a connection request frame (S107). The coordinator 31 transmits a connection response frame setting information required for connection to the tracked device (S108). Thereafter, the tracked device may communicate with the network. The tracked device connected to the network transmits a self-detection start frame to search for its location (S115). This frame is received by the reference devices 301, 302 and the coordinator 31 (PAN coordinator or cluster head). Using the received signal strength (RSS) and time information for the frame included in the frame, the location of the tracked device can be calculated. The reference devices 301, 302 send positioning data to the coordinator 31 (S121), which uses this data and a position tracking algorithm to calculate the position. If the coordinator 31 transmits a self-detection result frame including a position value to the tracked device 101 (S105), the tracked device 101 knows its position. Then, if the tracked device 101 is moved, since it is connected to the network, it can know its location through operations S115 to S150. The location tracking algorithm will be explained below.

The difference between a reference device and a tracked device depends on whether it is the object being tracked or not. Thus, since the tracked device 101 knows its location, it can now become the reference device. With other devices participating in the network, the tracked device 101 may act as a reference device and receive the other device's location information. Furthermore, even when device 101 acts as a reference device, if device 101 is moved, its new location can still be determined through operations 115-150. That is, although the device is a reference device, it can also be turned into a tracked device again. The distinction between a reference device and a tracked device depends on whether it is a reference used to determine the position of the device or an object being tracked.

FIG. 3 is a flowchart illustrating a process of requesting remote location identification by the coordinator 11 according to another exemplary embodiment of the present invention. Figure 3 shows an example of a passive scanning process where the network coordinator searches for tracked devices and sends this information. The new network device is marked as tracked device 102 to distinguish it from other network devices. The coordinator 11 continuously transmits beacon frames to maintain and manage the network (S201). The tracked device, which knows the existence of the network through the beacon frame, transmits a connection request frame (S207). If the coordinator 11 transmits a connection response frame accepting the connection request (S208), the tracked device 102 can communicate with the network.

In order to know the location of the tracked device, the coordinator 11 that has connected the tracked device to the network transmits a detection call request frame (S211). The detection call request frame is different from the self-detection start frame of FIG. 2 . In order to ensure confidentiality, it is determined whether the tracked device 102 allows location tracking in operation S212. When the tracked device 102 enables location tracking, it sends its location information to the coordinator as well as peripheral devices.

The tracked device 102 transmits a detect call response frame including its network identifier and a time stamp so that its location can be known (S215). The reference devices 401, 402 and the coordinator 11 receiving this frame locate the position and related data of the tracked device through information such as the received signal strength (RSS) and time information of the frame. The reference device 401 , 402 sends this positioning data to the coordinator ( S221 ), so that the coordinator 11 can use a location tracking algorithm to calculate the location of the tracked device 102 .

When the tracked device 102 does not allow location tracking, the tracked device 102 transmits a detect call rejection response frame to the coordinator and peripheral devices (S216).

Location information is important for network management. Therefore, although each device does not need to know the location information of the devices making up the network or cluster, the coordinator 11 needs to know the location information. Therefore, although the device refuses to advertise its location, the PAN coordinator or cluster head can get the location information of the device according to the network configuration.

When the location information is transmitted to both the PAN coordinator 31 and the cluster head 11 (Case 1), it is detected that a call rejection response frame is transmitted (S216). When the location information is only forcibly transmitted to the PAN coordinator 31 (Case 2), the tracked device cannot transmit the detect call rejection reply frame and the detect call reply frame.

In case 2, there is a method for sending a detect call answer frame unconditionally; ie, without asking the user whether he/she allows location tracking. For convenience of explanation, a method for transmitting a detect call response frame without user's permission will be explained below.

When the coordinator transmitting the detect call request frame is the cluster head, since only the PAN coordinator can forcibly obtain the location of other devices, the cluster head cannot obtain the location information of other devices. This is because the cluster only exists for a certain amount of time. Therefore, in the case where the tracked device 102 refuses to announce its own position, a detection call rejection frame is sent to the cluster head 11 and the reference devices 401, 402 (S216), and the process stops. When the location information is forced to be sent to the PAN coordinator and the cluster head, the tracked device 102 cannot reject the detection call request. The location of the device is advertised to the coordinator, with or without the user's permission. Thus, the process may proceed to operations S215 to S221 for user's convenience.

Operation S212 of FIG. 3 is optional. If the network can enforce knowledge of the location between devices, then the process proceeds regardless of whether the tracked device allows or denies location tracking. If the tracked device 102 is forcibly permitted to position track, processing proceeds to an operation in which the tracked device transmits a detection call response frame without transmitting a message requesting permission. At this time, only operations S201 to S221 are performed. Even if the user refuses location tracking, the location information can be sent to the coordinator, but it changes according to the user's permission or rejection.

On the other hand, for convenience, the user can set the response of the tracked device 102 in advance. For example, when the device requesting location tracking is the coordinator, the detection call response frame may be set to be sent unconditionally. The answer may be set in such a way that the tracked device 102 allows each device or only the devices in the cluster to which the tracked device 102 belongs to track its location. After this answer is set, a Check Call Answer frame is sent only to allowed devices or the coordinator, and a Check Call Reject answer is sent to all other devices without user input. The location tracking method of Figure 3 includes privacy protection. Therefore, operations S212 to S216 may be omitted according to the structure of the network.

2 and 3 show processes for participating in the network and for obtaining the location of the tracked device 102 . Execution of the process of FIG. 2 for actively connecting a network with a device requesting self-location identification is not unnecessary. The self-detection start frame may be sent after the tracked device is connected to the network through the passive scan of FIG. 3 . On the contrary, even after the active network scan of FIG. 2 , in order to know the location of the tracked device 102 , the coordinator may send a detect call request frame. In addition, the reference device may be a relay device that receives a frame for establishing the location of the tracked device and sends the location information contained in this frame to the cluster head.

4 is a flowchart illustrating a process in which a device other than a PAN coordinator or a cluster head requests a location tracked by a third device according to an exemplary embodiment of the present invention. In addition to Figures 2 and 3, additional operations may be required. Since tracking the location of other devices may violate user privacy, location tracking requests may be sent. Reference device 401 may request location tracking of device 102 . At this time, the device 401 may include its identifier, and a request for the identifier of the tracked device in the frame (S251). The coordinator (cluster head) 11 receives the detect call request frame and transmits it to the tracked device 102 (S252). The tracked device 102 knows that the reference device 401 wants to track its location. A message such as "Device 401 has requested location tracking. Do you allow location tracking?" may be displayed to the user of the tracked device 102 . If the user sees the message and allows location tracking, a frame (detect call answering frame) including time information for tracking its own location is transmitted (S255). The reference device 401, 402 receives the detection call response frame, calculates positioning data and sends this data to the coordinator (cluster head) 11 (S257). The coordinator 11 then transmits the location information of the tracked device 102 to the reference device 401 (S260).

However, when the user does not allow location tracking at operation S253, the device 102 transmits a detect call rejection response frame to the coordinator 11 and the reference devices 401, 402 (S256).

In FIG. 4 , information on whether the user of the tracked device 102 allows or refuses to detect a call answer can be set in advance, and it can be set for each device or for a specific device. With this setting, the user can maintain his/her privacy without answering location tracking queries.

FIG. 5 is a flowchart illustrating a process of tracking a location of a tracked device existing outside a cluster in which a PAN coordinator resides, according to an exemplary embodiment of the present invention. Referring to FIG. The embodiment of FIG. 5 includes a case where the PAN coordinator 31 requests the location of the tracked device 102 and a case where another device requests the location of the tracked device 102 .

The PAN coordinator 31 transmits a detect call request frame to the cluster head 11, 21 to track the location of a specific device at operation S311. The PAN coordinator 31 may also receive the location tracking frame sent by the cluster head CLH121 and send it to the whole network. The cluster head 11 receiving this frame transmits a detect call request frame to know whether the tracked device exists in its cluster (S312). Operations S311 and S312 may have the same or different contents according to frame specifics. The frame is received by the cluster head 11 at operation S311, and it is sent to the network devices in its cluster at operation S312. The tracked device 102 receives the detect call request frame, and determines whether it allows location tracking (S314).

If location tracking is allowed, a detection call response frame including location information is transmitted to the reference devices 301, 302 and the cluster head 11 (S315). The reference device transmits the positioning data obtained from the information included in the received detection call response frame to the cluster head 11 (S321). As a result, the cluster head 11 knows the location of the tracked device 102 and it transmits a detection result frame to the PAN coordinator 31 (S331).

Also, in this case, the process can be performed without asking the user of the tracked device whether he/she allows location tracking as previously described with reference to FIG. 3 . The detection call response frame may be sent to the PAN coordinator 31 even if there is a rejection response from the user.

The user of the tracked device 102 may prevent its location from being tracked if a third device attempts to track the location of the tracked device 102 through the PAN coordinator 31 or if the PAN coordinator 31 does not enforce location tracking of other devices. Here, the tracked device 102 transmits the detection call rejection response frame to the reference devices 301, 302 and the cluster head 11 (S316). The cluster head 11 transmits the received detect call rejection response frame to the PAN coordinator 31 (S317) and the PAN coordinator 31 knows that the tracked device cannot be tracked. Additionally, the Detect Call Rejection Reply frame may be sent to other devices requesting the location of the tracked device 102 .

6 is a flowchart illustrating a process of device location tracking using a relay device according to another exemplary embodiment of the present invention. The PAN coordinator can directly send the detect call request to the cluster head, or the PAN coordinator can send it to the cluster head indirectly through another cluster head. Therefore, the cluster header that receives and transmits the detection call request frame functions as a relay.

In FIG. 6, the PAN coordinator 31 transmits a detect call request frame to the cluster head 51 (S411). The cluster head 51 transmits the detect call request frame to the third cluster head 11 (S412) and the cluster head 11 tracks the locations of devices existing in its cluster. Here, as shown in the examples of FIGS. 2 to 5 , different methods are performed depending on whether the tracked device permits or denies location tracking.

When the tracked device allows its position to be tracked in operation S414, the cluster head 11 calculates the position of the tracked device in operation S420, tracks the position and sends the detection result frame to the cluster head 51 (S431), which also sends the detection result To PAN coordinator 31_ (S432).

When the location tracking is rejected by the tracking device at operation S414, the cluster head 11 generates a detection call rejection response frame at operation S422, and transmits the detection call rejection response frame (S434). The relay device 51 receiving the detected call rejection response frame transmits the detected call rejection response frame to the PAN coordinator 31 (S436).

There are a number of location tracking algorithms that can be used.

FIG. 7 is a conceptual diagram illustrating location tracking by a time of arrival (TOA) method according to an embodiment of the present invention. The TOA method measures transit times of signals sent between the tracked device 101 and other network devices 11 , 301 , 302 to calculate distances. The signal delivery time can be obtained by the difference between the transmission time of the frame (eg, since detection start and detection call answer). By calculating this difference and knowing the speed of the signal containing the frame, three spherical ranges with the network device 11, 301, 302 as their centers are obtained. Three devices are required to perform the calculations for this method. If at least three reference devices send the value, the coordinator 11 may select the three data values judged to be the most accurate. In one embodiment, the accuracy of these data values can be judged by the received signal strength. For example, Table 1 shown below lists the four devices 11, 301, 302, 307 and the RSS and positioning data of the signals transmitted by these devices. Since device 307 of Table 1 has the weakest received signal strength, it is ignored (location data from this device may be inaccurate).

Table 1 - RSS values and targeting data device RSS location data (m) 11 70 15 301 80 10 302 90 8 307 30 10

However, received signal strengths are exemplary and reference means may be determined from signal distortion or other characteristics of the signal.

FIG. 8 illustrates location tracking by a time difference of arrival (TDOA) method according to an exemplary embodiment of the present invention. The TDOA method measures the difference between arrival times of two signals to determine a position, and includes a forward chaining method consisting of multiple signal sources and one receiver and a reverse chaining method consisting of one signal source and multiple receivers. The basic principle of TDOA is that the signal arrival time difference is proportional to the difference between the distances from the two signal sources to the receiver. These distances are calculated, and receivers equidistant from the two signal sources, ie lying on a hyperbola centered at the two signal sources, are selected. At this time, each base station must be synchronized, and the time synchronization of the base stations is achieved using satellite clocks. Two hyperbolas are obtained from three signal sources, and the intersection of the two curves is the location of the receiver.

Figure 8 shows the application of TDOA in IEEE 802.15.4. Here, the intersection point of the hyperbola obtained from the network device 11 , 301 and the hyperbola obtained from the network device 11 , 302 is the position of the tracked device 101 . To obtain the intersection between the hyperbolas, TOA data is sent by the reference network device 301 , 302 to the coordinator 11 . If the coordinator 11 receives several signals, it can select a device according to the RSS and calculate positioning data.

In addition to the methods described in FIGS. 7 and 8, an angle of arrival (AOA) method and a radio frequency (RF) fingerprint method may be used. The AOA method measures an incident angle of a frame signal transmitted from a tracked device, and searches in this direction. In this embodiment, the strongest signal may be selected among the values measured by several network devices.

The RF fingerprinting method takes a snapshot of the received signal, analyzes the snapshot and extracts unique features of the signal, and compares this signal to an existing database to locate receivers to obtain feature values for frames sent by the tracked device.

The location tracking algorithms explained in this specification are exemplary only.

FIG. 9 illustrates a frame format of a MAC layer for embodying a location tracking function according to an exemplary embodiment of the present invention. Figure 9 shows one embodiment using the TOA algorithm, and may vary depending on the location tracking method.

The frame control of the IEEE 802.15.4 command frame 700 is 16 bits, and contains the type of frame, address field and control flag. The sequence number is the unique identifier of the frame. The address field includes a recipient's PAN identifier/address field and a sender's PAN identifier/address field. The command frame identifier shows which command is being executed and can take the values shown in table 720 . 0x0b to 0xff are reserved and may be defined in the future. Therefore, location tracking commands can be defined using these reserved identifiers.

The command payload is required to execute the command and may take the values shown in table 710.

The self-detection start frame 711 transmitted when a tracked device wants to know its location has a command frame identifier 0x21, and corresponds to a command payload consisting of a tracked device identifier and a frame transmission time. Other reference devices (including the coordinator) receiving the frame can use the frame transmission and reception times to calculate distances. This distance or data is sent to the coordinator, revealing the location of the tracked device.

The calculated result is sent through the self-detection result frame 712 having the command frame identifier 0x22 and the command payload composed of the location information and the tracked device identifier.

Next, structures of a detect call request frame 713 , a detect call reply frame 714 , and a detect call reject reply frame 717 sent in case of rejecting location tracking will be described. The detect call request frame 713 is transmitted when searching for a tracked device existing in the sender's network and when searching for a reference device not existing in the sender's network. The command payload includes the identifier of the network device being searched. A tracked device receiving this frame sends a detect call reply frame 714 to disclose its location. The command payload included here, like the start-from-detection frame 711, may be the identifier of the tracked device and the time of transmission. On the other hand, when the tracked device refuses location tracking, a detect call rejection response frame 717 is transmitted. The command payload included therein may be an identifier of the tracked device.

The self-detect start frame 711 and the detect call answer frame 714 include basic data for location tracking. When the TOA method or the TDOA method is used, the basic data may be the transmission time, and when the RF fingerprint method is used, the basic data may be the signal strength. By combining this information, the location of the tracked device can be calculated. Position data frame 715 provides the functionality to send calculated data to the coordinator. The calculated data may be the time difference between frame transmission and reception, or it may be distance information calculated from time difference information. In addition, the calculated data may be information combining the incident angle and distance information of the signal. In addition, the command payload may be positioning data calculated by information included in the self-detection start frame 711 and the detection call response frame 714 , RSS, and the location of the reference device from which the data was calculated. RSS is used to extract the most reliable data when several network devices send calculated data. Therefore, the content of the payload may change according to the location tracking algorithm. In addition, since the calculated data is related to the position of the reference device, the position information of the reference device is required. If the coordinator of the network stores the locations of all devices present in its network, the location of the reference device does not have to be sent and may vary depending on the coordinator.

The detection result frame 716 is used when a cluster head of a network device connection transmits location information to a PAN coordinator when a PAN coordinator requesting location tracking of a specific network device exists in the PAN different from the network device PAN. The cluster header transmits a command frame and a payload including a PAN identifier, an identifier of a tracked device, and location information to the PAN coordinator.

The above-mentioned command is an exemplary embodiment for embodying the position identification, detection result, position identification request, and position information frame used in the claims of this specification. Self-detection start frame 711 and detection call response frame 714 are examples of position recognition frames, and detection result frames 712 and 716 are examples of detection result frames. The detection call request frame 713 is an example of a location recognition request frame, and the positioning data frame 715 is an example of a location information frame.

The device identifier of the command, for example, the device identifier defined by the detect call request frame 713 may include a plurality of pieces of identifier information in various ways. That is, the device identifier may include an identifier of a device being tracked, an identifier of a device requesting location tracking. Also, when searching for a device in another cluster, the identifier of the target cluster should be included in addition to the device identifier.

10, 11, 12 are block diagrams illustrating command payloads of frames according to exemplary embodiments of the present invention.

Fig. 10 shows that the identifier information in the payload of the detection call request frame changes according to the conditions. In the case of FIG. 3, since the cluster head searches for the tracked device, the frame 7131 includes only the identifier of the tracked device. In the case of FIG. 4 , since the reference device searches for the tracked device, the frame 7132 includes the identifier of the device requesting location tracking and the identifier of the tracked device. In the case of FIGS. 5 and 6, since the device being tracked exists in another cluster, the frame 7133 is structured to include the identifier of the device requesting location tracking, the cluster identifier, and the ID of the device that is the object of location tracking. identifier. In order to distinguish each frame, a detection flag may be included in the command frame.

Fig. 11 shows that the identifier information in the payload of the detection call response frame changes according to the conditions. Similar to FIG. 10 , in the case of FIG. 3 , frame 7141 includes the identifier of the tracked device and the time of transmission. In the case of FIG. 4 , since the reference device searches for the tracked device, the frame 7142 includes the identifier of the device requesting location tracking, the identifier of the tracked device, and the transmission time. In the case of FIGS. 5 and 6, since the device being tracked exists in another cluster, the frame 7143 includes the identifier of the device requesting location tracking, the cluster identifier, the identifier of the device being tracked, and the transmission time . In order to distinguish each frame, a check flag may be included in the command frame.

Fig. 12 shows that the identifier information in the payload of the detection call rejection response frame changes according to conditions. 0x27 is an identifier for detecting call rejection response frames. This structure is similar to that of the detection call answering frame of FIG. 11 , but it does not include information related to location tracking, such as transmission time information, since location tracking has been rejected. The detection call rejection response frame is a frame for announcing that the tracked device refuses location tracking. In the case of FIG. 3 , an identifier 7151 of a device that is an object of location tracking but refuses location tracking is included. As in the case of FIG. 4 , when a tracked device rejects location tracking, a frame 7152 is transmitted, and the frame includes an identifier of a device requesting location tracking and an identifier of a device that is an object of location tracking. When a device in another cluster requests location tracking, frame 7153 is transmitted, and it includes a cluster identifier of the cluster in which the requesting device resides, a device identifier, and an identifier of a device that is a target of location tracking.

According to the present invention, the location of a device can be tracked in a coordinator-based wireless network.

Specifically, a protocol that can perform location tracking in the IEEE 802.15.4a environment is provided.

While this invention has been particularly shown and described with reference to exemplary embodiments thereof, it should be understood by those skilled in the art that modifications may be made thereto without departing from the spirit and scope of the invention as defined by the appended claims. and various changes in details. These exemplary embodiments should be considered in a descriptive sense only and not for purposes of limitation. Therefore, the scope of the invention is defined not by the detailed description of the invention but by the appended claims, and all differences within the scope will be construed as being included in the present invention.

Claims (51)

1, a kind of based on the location tracking method in the wireless network of telegon, comprising:

To comprise that by the device that is connected with wireless network first frame of identifier and temporal information sends to wireless network to disclose the positional information of this device; With

Reception comprises from the acknowledgement frame of the positional information of the described device of described wireless network transmission.

2, the method for claim 1, wherein described wireless network uses IEEE 802.15.4 agreement.

3, the method for claim 1, wherein described temporal information transmitting time that is first frame.

4, the method for claim 1, wherein described identifier Media Access Control address that is described device.

5, the method for claim 1, wherein, described device is a kind of like this device, its request is used to check the detection of the existence of wireless network, receive the response detected of wireless network of the existence of self-checking wireless network, request is connected to described wireless network and receives and replys from the connection of this wireless network.

6, the method for claim 1, wherein described device is a kind of like this device, and it receives the beacon of wireless network of the existence of self-checking wireless network, and request is connected to described wireless network and receives and replys from the connection of this wireless network.

7, a kind of based on the location tracking method in the wireless network of telegon, comprising:

First frame that will comprise the identifier of first device and second device sends to wireless network, so that be connected to the position that first device of wireless network is known second device; With

Receive the acknowledgement frame that comprises from second positional information of installing of described wireless network transmission by first device.

8, method as claimed in claim 7, wherein, described wireless network uses IEEE 802.15.4 agreement.

9, method as claimed in claim 7, wherein, the identifier of described first and second devices is respectively the Media Access Control address of first and second devices.

10, method as claimed in claim 7, wherein, described first device is a kind of like this device, its request is used to check the detection of the existence of wireless network, receive the response detected of wireless network of the existence of self-checking wireless network, request is connected to described wireless network and receives and replys from the connection of described wireless network.

11, method as claimed in claim 7, wherein, first device is a kind of like this device, and it receives the beacon of wireless network of the existence of self-checking wireless network, and request is connected to described wireless network and receives and replys from the connection of described wireless network.

12, a kind of based on the location tracking method in the wireless network of telegon, comprising:

Install first frame that receives from the identifier of first identifier that installs of asking comprising of wireless network second position of installing to be followed the tracks of and second device by second; With

To comprise that by second device identifier of first device, the identifier of second device and second frame of second temporal information of installing send to wireless network, as replying to first frame.

13, method as claimed in claim 12, wherein, described wireless network uses IEEE 802.15.4 agreement.

14, method as claimed in claim 12, wherein, the identifier of first and second devices is respectively the Media Access Control address of first and second devices.

15, method as claimed in claim 12, wherein, described temporal information is the transmitting time of second frame.

16, a kind of based on the location tracking method in the wireless network of telegon, comprising:

Install first frame that receives from the identifier of first identifier that installs of asking comprising of wireless network second position of installing to be followed the tracks of and second device by second;

Determine whether to allow the position to follow the tracks of; With

If allow the position to follow the tracks of, then will comprise that from second device identifier of first device, the identifier of second device and second frame of temporal information send to wireless network, as replying to first frame.

17, method as claimed in claim 16, wherein, determine that operation comprises: assessment is by the value of user's input of second device that is allowed to or refuses follow the tracks of the position.

18, method as claimed in claim 16, wherein, definite operation comprises: relatively come to determine by the value and first identifier that installs that will before be provided with in second device.

19, method as claimed in claim 16, wherein, when finding that in determining operation the position tracking is rejected, second frame comprises the identifier of first device and the identifier of second device.

20, method as claimed in claim 16, wherein, described wireless network uses IEEE 802.15.4 agreement.

21, method as claimed in claim 16, wherein, the identifier of first and second devices is respectively the Media Access Control address of first and second devices.

22, a kind of based on the location tracking method in the wireless network of telegon, comprising:

Reception is by the identifier that comprises this device of device transmission and first frame of temporal information;

Use described temporal information to obtain to be used to calculate the position calculation information of the position of described device; With

To comprise that the identifier of described device and second frame of described position calculation information send to network coordinator.

23, method as claimed in claim 22, wherein, described wireless network uses IEEE 802.15.4 agreement.

24, method as claimed in claim 22, wherein, described temporal information is the transmitting time of described first frame.

25, method as claimed in claim 24, wherein, poor between time of reception that described position calculation information is first frame and the transmitting time.

26, method as claimed in claim 22, wherein, the identifier of described device is the Media Access Control address of described device.

27, a kind of based on the location tracking method in the wireless network of telegon, comprising:

Identifier and the identifier of second device and first frame of the second setup time information of first device that follow the tracks of the position that comprises request second device that reception is sent by second device;

Use described temporal information to obtain to be used to calculate the position calculation information of second position of installing; With

To comprise that the identifier of first device, the identifier of second device and second frame of position calculation information send to network coordinator.

28, method as claimed in claim 27, wherein, described wireless network uses IEEE 802.15.4 agreement.

29, method as claimed in claim 27, wherein, described temporal information is the transmitting time of first frame.

30, method as claimed in claim 29, poor between the time of reception that wherein said position calculation information is first frame and the transmitting time of first frame.

31, a kind of based on the location tracking method in the wireless network of telegon, comprising:

Receive a plurality of frames of the position calculation information of the identifier that comprises device of automatic network and described device;

Use the position of the described device of described position calculation information calculations; With

The frame that will comprise positional information sends to described device.

32, method as claimed in claim 31, wherein, described wireless network uses IEEE 802.15.4 agreement.

33, method as claimed in claim 31, wherein, the identifier of described device is the Media Access Control address of described device.

34, a kind of based on the location tracking method in the wireless network of telegon, comprising:

The identifier of first device that follow the tracks of the position that receives ask second device comprising of automatic network, the identifier of second device and a plurality of frames of the second position calculation information of installing;

Use the position of described position calculation information calculations second device; With

The frame that will comprise the position of second device sends to first device.

35, method as claimed in claim 34, wherein, described wireless network uses IEEE 802.15.4 agreement.

36, method as claimed in claim 34, wherein, the identifier of described first and second devices is respectively the Media Access Control address of first and second devices.

37, a kind of based on the address tracking in the wireless network of telegon, comprising:

First frame of the identifier of first device that follow the tracks of the position that receives ask second device comprising of automatic network and the identifier of second device;

Described first frame is sent to second device of described network;

Be used to announce the position from the second device reception and follow the tracks of unaccepted second frame; With

Described second frame is sent to described first device.

38, method as claimed in claim 37, wherein, described wireless network uses IEEE 802.15.4 agreement.

39, method as claimed in claim 37, wherein, the identifier of described first and second devices is respectively the Media Access Control address of first and second devices.

40, a kind of based on the location tracking method in the wireless network of telegon, comprising:

First frame that comprises first identifier that installs and second identifier that installs that reception is sent by first device is so that the telegon of first wireless network can be followed the tracks of second device;

To comprise that by the telegon of described first wireless network second frame of identifier, described first identifier that installs and described second identifier that installs of described first wireless network sends to the telegon of second wireless network;

Telegon by described first wireless network receives by the identifier of the identifier that comprises described first wireless network of the telegon transmission of described second wireless network, the identifier of described first device, described second device and the 3rd frame of described second positional information of installing, as replying described second frame; With

Telegon by described first wireless network will comprise that the 4th frame of the positional information of described second device sends to first device.

41, method as claimed in claim 40, wherein, described first and second wireless networks use IEEE 802.15.4 agreement.

42, method as claimed in claim 40, wherein, the identifier of described first and second devices is respectively the Media Access Control address of first and second devices.

43, a kind of based on the location tracking method in the wireless network of telegon, comprising:

First frame that comprises first identifier that installs and second identifier that installs that reception is sent by first device is so that the telegon of first wireless network can be followed the tracks of described second device;

To comprise the identifier of the identifier of described first wireless network, described first device and the telegon that described second identifier that installs sends to described second wireless network by the telegon of described first wireless network;

If having received the described second device refusal position of second frame follows the tracks of, then the telegon by described first wireless network receives the identifier of the identifier that comprises described first wireless network, described first device and the 3rd frame of described second identifier that installs, as replying of second frame; With

Telegon by described first wireless network will comprise that the 4th frame of the information of following the tracks of about the described second device refusal position sends to described first device.

44, method as claimed in claim 43, wherein, described first and second wireless networks use IEEE 802.15.4 agreement.

45, method as claimed in claim 43, wherein, the identifier of described first and second devices is respectively the Media Access Control address of first and second devices.

46, a kind of based on the location tracking method in the wireless network of telegon, comprising:

Receive first frame of the identifier of the identifier of first device of the position of the identifier that comprises first wireless network that the telegon by first wireless network sends, request second device following the tracks of and second device by the telegon of second wireless network;

To comprise that by the telegon of described second wireless network identifier of the identifier of described first wireless network, described first device and the identifier of second device send to second device that is connected with second wireless network;

Receive the identifier of the identifier of the identifier that comprises first wireless network from described second wireless network, described first device, described second device and a plurality of second frames of the second position calculation information of installing by the telegon of described second wireless network;

Use the position of described second device of described position calculation information calculations of second device by the telegon of described second wireless network; With

To comprise that by the telegon of second wireless network the 4th frame of positional information of described second device of the identifier of the identifier of the identifier of described first wireless network, described first device, described second device and calculating sends to the telegon of described first wireless network.

47, method as claimed in claim 46, wherein, described first and second wireless networks use IEEE 802.15.4 agreement.

48, method as claimed in claim 46, wherein, the identifier of described first and second devices is respectively the Media Access Control address of first and second devices.

49, a kind of based on the location tracking method under the wireless network of telegon, comprising:

Reception is by the identifier that comprises first wireless network of the telegon transmission of first wireless network, first identifier that installs of asking the second position tracking of installing and first frame of second identifier that installs;

To comprise that by the telegon of second wireless network second frame of identifier, described first identifier that installs and described second identifier that installs of described first wireless network sends to the telegon of the 3rd wireless network;

Receive the identifier of the identifier of the identifier that comprises described first wireless network that sends by described the 3rd wireless network, described first device, described second device and the 3rd frame of described second positional information of installing by the telegon of described second wireless network; With

To comprise that by the telegon of described second wireless network the 4th frame of identifier, described second identifier that installs and described second positional information of installing of the identifier of described first wireless network, described first device sends to the telegon of described first wireless network.

50, method as claimed in claim 49, wherein, described first, second uses IEEE 802.15.4 agreement with the 3rd wireless network.

51, method as claimed in claim 49, wherein, the identifier of described first and second devices is respectively the Media Access Control address of first and second devices.

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