KR20180025613A - Method for time compensation in long range network terminal and terminal performing same - Google Patents

Abstract

According to an embodiment of the present invention, provided is a method to correct time information of a long range (LoRa) network terminal connected to a LoRa network server. The method includes: a step of transmitting a first time information request message to the LoRa network server at a first time point (t_1); a step of receiving a reception confirmation message about the first time information request message transmitted by the LoRa network server at a second time point (t_2); a step of transmitting a second time information request message to the LoRa network server at a third time point (t_3) after the second time point; a step of receiving a time information message recorded with reference time (T_ref) determined based on a time point at which the LoRa network server transmits a reception confirmation message about the first time information request message at a fourth time point (t_4); and a step of correcting time information of the terminal based on an interval between the first time point and the second time point, an interval between the second time point and the fourth time point, and the reference time.

Description

TECHNICAL FIELD [0001] The present invention relates to a time correction method for a LoRa network terminal and a terminal for performing the method. [0002]

The present invention relates to a method for accurately correcting a time of a terminal connected to a LoRa (Long Range) network system and a terminal performing the method.

Internet of Things (IoT) is an intelligent technology and service that connects various objects through a network such as the Internet and enables information between people, things, objects and objects to communicate with each other. Such Internet is more advanced than existing wired / wireless communication, and can be utilized in various fields such as unmanned meter, unmanned vending machine, intelligent transportation service, and real time monitoring medical service. According to the results of the research on IoT devices and analysis of them, the number of Internet access devices is expected to increase to about 30 billion by 2025, and researches on the utilization of IoT are being actively carried out.

Wi-Fi, Bluetooth and the like have conventionally been used as a communication method for constructing such an object Internet system. However, these methods are disadvantageous in that they can communicate only at a relatively short distance, and thus are not suitable for the object Internet system which needs to cover a wide range. The communication method for the Internet for objects needs to be designed so that power consumption can be reduced for a large number of object internet appliances that can cover a wide range as described above, and are often required to be constantly charged with power supply. Accordingly, a demand for a so-called low power wide-area (LPWA) has been raised. LPWA is a term collectively referred to as IoT network technology specialized for small amount data transmission, which is characterized by wide coverage and low power consumption, which allows low-speed transmission of 1 kbps or less.

The LoRa (Long Range) network is one of the networks of the LPWA system. In general, the LoRa (Long Range) network does not require high speed real time data transmission / reception to the object Internet system. By adopting a downward asymmetric transmission scheme, power consumption is reduced. LoRa network is an IoT dedicated network that can accommodate low-performance devices of small batteries for the implementation of Small Things Internet. It can provide a speed of 293bps ~ 5.4kbps and coverage of -143dbm sensitivity. Also, the LoRa network terminal can receive the reception data transmitted from the base station only after a predetermined time has elapsed after transmitting the transmission data to the base station due to the restriction of the data transmission / reception as described above.

On the other hand, in the case of utilizing the Internet of objects such as unmanned metering or traffic services, time synchronization between Internet terminals is very important. In order to do this, it is necessary to transmit time information from the reference time providing device which maintains accurate time to the object Internet terminal. However, since the LoRa network terminal having the transmission characteristics as described above can not receive the time information in real time even if the time information is requested to the reference time providing apparatus, deriving the time correction method of the terminal considering the characteristics of the LoRa network system It is necessary situation.

Korean Unexamined Patent Publication No. 10-2011-0059421 (published on June 2, 2011)

SUMMARY OF THE INVENTION The present invention provides a method for effectively correcting a time of a terminal in a LoRa network system in which real-time data transmission and reception of a terminal is impossible, and a terminal to which the method is applied.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are exemplary and explanatory and are intended to provide further explanation of the invention as claimed. will be.

A method for correcting time information of a LoRa network terminal connected to a LoRa network server according to an embodiment of the present invention includes transmitting a first time information request message to the LoRa network server at a first time point t ₁ . Receiving an acknowledgment message for the first time information request message sent from the LoRa network server at a second time point (t ₂ ); Wherein the third time after the second point in time (t _3), the method comprising: transmitting a second time information request message to the LoRa network server, and the fourth point in time (t _4), the information the LoRa network server is the first time Receiving a time information message in which a predetermined reference time (T _ref ) is recorded based on a time point at which an acknowledgment message for the request message is transmitted; and transmitting the time information message including the reference time, the interval between the second time point and the fourth time point, And correcting the time information of the terminal based on the interval between the first time point and the second time point.

A terminal connected to a LoRa network server through a LoRa (Long Range) network according to an embodiment of the present invention includes a communication unit for performing data transmission to the LoRa network server and data reception from the LoRa network server, A time information request message is transmitted to the LoRa network server through the communication unit at a first time point t ₁ and a reception acknowledgment message for the first time information request message sent from the LoRa network server is transmitted at a second time point t ₂ via the communication unit and transmits the second time information request message to the LoRa network server through the communication unit at a third time point t ₃ after the second time point, the criteria set on the basis of the time of transmitting the acknowledgment message for the first time the time information request message (T _ref) is the recorded time information On the basis of the message in the interval between the fourth time (t ₄₎ a control unit for receiving via the communication unit and the reference time, the second time point and the fourth the second time point and interval and the first time point between time point , And a correction unit for correcting the time information of the terminal.

According to an embodiment of the present invention, a LoRa network terminal receives reference time information from a LoRa network server, and uses a time interval between a plurality of message exchanges performed between a LoRa network terminal and a LoRa network server as a kind of offset, The correction time information can be calculated by correcting the reference time information. Accordingly, it is possible to easily and accurately correct the time of the LoRa network terminal using only the characteristics of the LoRa network system without adding an additional device to the terminal.

1 is a diagram illustrating a configuration of a LoRa network system according to an embodiment of the present invention.
2 is a diagram illustrating data transmission in a LoRa network system according to an embodiment of the present invention.
3 is a diagram illustrating a configuration of a terminal for performing a time correction method in a LoRa network terminal according to an embodiment of the present invention.
4 is a diagram illustrating a procedure of a time correction method performed through a LoRa network terminal according to an embodiment of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions in the embodiments of the present invention, which may vary depending on the intention of the user, the intention or the custom of the operator. Therefore, the definition should be based on the contents throughout this specification.

1 is a diagram illustrating a configuration of a LoRa network system according to an embodiment of the present invention. The LoRa network system 10 shown in FIG. 1 is a network system to which the LoRa network system as described above is applied and includes a LoRa network terminal 100, a LoRa network server 200, a LoRa network base station 300, and a LoRa application server 410, . ≪ / RTI > However, the constituent elements of the LoRa network system 10 of FIG. 1 and the connection relationship between the respective constituent elements are only one embodiment of the present invention, and therefore the technical idea of the present invention is not limited to FIG.

Hereinafter, the LoRa network system 10 and the respective components will be briefly described with reference to FIG. The LoRa network terminal 100 may be a variety of object Internet devices such as an automatic meter and a traffic information collecting device. The LoRa network server 200 is capable of managing the LoRa network system 10 and more specifically registering and authenticating the LoRa network terminal 100 and assigning the IDs to the LoRa network server 100 and interworking between the LoRa network terminal 100 and the application server 410 A base station selection for the LoRa network terminal 100, and a policy setting for the LoRa network provider. The LoRa network terminal 100 and the LoRa network server 200 can exchange data with each other through the LoRa network base station 300. [

Meanwhile, the LoRa network server 200 may be further connected to the reference time providing apparatus 400 that provides the LoRa network server 200 with reference time information based on the standard time of the area to which the LoRa network system 10 belongs. The reference time providing apparatus is a device having accurate time information by Universal Time Coordinated (UTC), for example, as a LoRa application server 410 or a LoRa network system 10 included in the LoRa network system 10 An external time information providing server 420 for providing reference time information from outside, and the like.

The LoRa application server 410 may be included in the LoRa network system 10 as described above and may receive data from the LoRa network server 200, encrypt / decrypt the data packets, Service provision and management / control related to the application service. The LoRa application server 410 can be managed by the service manager 500 and can maintain an accurate time through NTP (Network Time Protocol). On the other hand, the external time information server 420 may exist outside the LoRa network system 10, and may be any apparatus that can maintain an accurate time through a Global Positioning System (GPS) device or the like.

2 is a diagram illustrating data transmission in a LoRa network system according to an embodiment of the present invention. The asymmetric transmission method as described above is applied to the LoRa network terminal 100 under the LoRa network system 10 so that data reception can be performed only after a predetermined time has elapsed since the data transmission. Therefore, even if data is transmitted to the LoRa network server 200 through the LoRa network base station 300, the response can not be immediately received.

More specifically, it is assumed that the LoRa network terminal 100 transmits the transmission data packet 101 to the LoRa network base station 300, and the transmission ends at the first time point t ₁ . Then, the LoRa network terminal 100 enters a sleep mode for a predetermined first waiting time T ₁ from the first time t ₁ , which is the end of transmission. During the sleep mode, the LoRa network terminal 100 can not perform data transmission / reception.

When the sleep mode ends at the second time point t ₂ , the LoRa network terminal 100 enters a data reception mode in which data can be received through the LoRa network base station 300. To be more exact description, the data transmitted to the LoRa network terminal 100 is a second point in time (t ₂₎ LoRa network terminal 100 from LoRa network base station 300 during a first reception time (e.g., 20ms) determined group from ( 102, and if there is data 102, it is received. If not, the data reception mode is terminated when the first reception time elapses from the second time point t ₂ . 2, after the predetermined second waiting time T ₂ has elapsed from the first time point t ₁ , the LoRa network terminal 100 enters the data receiving mode again, It is possible to detect whether there is data transmitted from the base station 300 to the LoRa network terminal 100. As in the case of the first reception time, the LoRa network terminal 100 receives data transmitted from the LoRa network base station 300, and if not, terminates the data reception mode after the second reception time (for example, 20 ms) do. The first and second waiting times T ₁ and T ₂ can be set arbitrarily. However, in the general LoRa network system 10, the first and second waiting times T ₁ and T ₂ are set to 1 second and 2 seconds, respectively . The LoRa network terminal 100 transmits a message requesting the LoRa network server 200 to transmit specific data to the LoRa network server 200 via the LoRa network base station 300, , And in some cases a response to the request may be received after 2 seconds.

In Figure LoRa network environment as above described with reference to, for example LoRa network terminal 100 LoRa the data 101 request including a message for requesting the specific information in the first time point (t _1), a network server (200 ). The LoRa network server 200 may transmit the data 102 including the acknowledgment message indicating that the request is received to the LoRa network terminal 100 at the second time point t ₂ . If it takes time to process the request, the LoRa network server 200 may not be able to transmit the specific information requested by the LoRa network terminal 100 at the second time point t ₂ . In this case, LoRa network terminal 100 is a second point in time (t ₂₎ to send to a particular time of a third time (t ₃₎ the data (103) to re-LoRa network server 200 includes a request message for the subsequent And the LoRa network server 200 that processed the request can transmit the data 104 containing the specific information requested by the LoRa network terminal 100 to the LoRa network terminal 100 at the fourth time point t ₄ have. At this time, the time interval between the first time point t ₁ and the second time point t ₂ and the time interval between the third time point t ₃ and the fourth time point t ₄ are set to the first waiting time T ₁ ) Or a second waiting time (T ₂ ).

3 is a diagram illustrating a configuration of a terminal for performing a time correction method in a LoRa network terminal according to an embodiment of the present invention. The LoRa network terminal 100 of FIG. 3 may include a communication unit 110, a control unit 120, and a correction unit 130. However, the components of the LoRa network terminal 100 of FIG. 3 and the functions of the respective components are only examples of the present invention, and therefore the technical idea of the present invention is not limited to FIG. Hereinafter, the operation of each component included in the LoRa network terminal 100 will be briefly described with reference to FIG. 3, and further details will be described with reference to FIG.

The communication unit 110 can perform data transmission to the LoRa network server 200 and data reception from the LoRa network server 200 under the control of the control unit 120. [ Such data transmission and reception can be performed via the LoRa network base station 300 as described above. The communication unit 110 may be implemented through a wired or wireless communication module.

The control unit 120 may control the communication unit 110 to transmit and receive data. The data transmitted from the LoRa network terminal 100 to the LoRa network server 200 through the operation of the controller 120 may include reference time information for obtaining accurate time information, And a time information request message for requesting the provision of the time information. Alternatively, the data received from the LoRa network server 200 to the LoRa network terminal 100 may include acknowledgment (Acknowledge or Ack) for the time information request message, a time information message including reference time information, .

The correcting unit 130 corrects the time information of the LoRa network terminal 100 on the basis of the time when the control unit 120 transmits or receives the data through the communication unit 130 and the reference time information recorded in the time information message Can be corrected. The correction unit 130 may be implemented by a computing unit including a microprocessor together with the control unit 120 described above.

In addition, the LoRa network terminal 100 may further include a storage unit (not shown) capable of storing data for the above components. Examples of the computer readable recording medium include magnetic media such as a hard disk, a floppy disk and a magnetic tape, an optical recording medium such as a CD-ROM and a DVD optical media, magneto-optical media such as a floppy disk, and hardware devices that are specially configured to store and execute program instructions such as flash memory.

4 is a diagram illustrating a procedure of a time correction method performed through a LoRa network terminal according to an embodiment of the present invention. Each step of the interworking method according to an embodiment of the present invention will be described with reference to FIG. Refers to a point on an absolute time axis, and the term " time " refers to numerical data (for example, 15:47 38 seconds).

First, the LoRa network terminal 100 may transmit a first time information request message for requesting accurate reference time information at a first time point t ₁ through the LoRa network base station 300 (S101). Then, the LoRa network base station 300 can transmit the first time information request message to the LoRa network server 200 (S102). Upon receipt of the first time information request message, the LoRa network server 200 transmits an acknowledgment message for the first time information request message to notify the LoRa network terminal 100 that it has received the first time information request message, And transmit it through the base station 300 (S103). This LoRa network terminal 100 may receive the acknowledgment message to the second point in time (t ₂₎ through LoRa network base station (300) (S104). As described above, the interval between the first time point t ₁ and the second time point t ₂ may be the length (T ₁ ) of the sleep mode described in FIG. 2 under a general situation, for example, have.

On the other hand, when the LoRa network server 200 receives the first time information request message, the LoRa network server 200 may transmit a first time information request message to the reference time providing apparatus 400 (S105). Then, the reference time providing apparatus 400 transmits to the LoRa network server 200 a time information message in which the reference time (T _ref ) based on the precise time of receiving the first time information request message, that is, the standard time information, is recorded (S106). However, due to the restriction on data transmission / reception of the LoRa network system 10, the LoRa network server 200 can not send the time information message together with the acknowledgment message for the first time information request message, The LoRa network terminal 100 can not receive the time information message at the second time point. Accordingly, in order to receive the time information message, the time correction method according to an embodiment of the present invention may further include the following steps.

At the third time point t ₃ after the second time point t ₂ , the LoRa network terminal 100 can transmit a second time information request message for receiving the time information message through the LoRa network base station 300 (S107). Then, the LoRa network base station 300 can transmit the second time information request message to the LoRa network server 200 (S108). At this time, the LoRa network server 200 receiving the second time information request message transmits an acknowledgment message for the second time information request message to inform the LoRa network terminal 100 that the second time information request message has been received Can be transmitted through the LoRa network base station 300, and at the same time, the time information message can be transmitted together (S109). This LoRa network terminal 100 may receive the acknowledgment message, and time information message to the fourth point in time (t ₄₎ through LoRa network base station (300) (S110). As described above, the interval between the third time point t ₃ and the fourth time point t ₄ is also the same as the interval between the first time point t ₁ and the second time point t ₂ in a general situation, The first waiting time T ₁ or the second waiting time T ₂ , which is the length of the sleep mode, and the interval may be, for example, 1 second or 2 seconds, as described above.

Finally, LoRa network terminal 100 is recorded in the time information message reference time (T _ref), a second point in time (t ₂₎ and a fourth point in time (t _4), the spacing between and the first point in time (t ₁₎ and it is possible to correct the time information of LoRa network terminal 100 on the basis of the distance between the second point in time (t ₂₎ (S111).

The LoRa network terminal 100 needs to send the time information request message twice as described above. But here the fourth time when LoRa network terminal 100 receives the time information message from the (t ₄₎ and, between the time transmitted for the first time information request message to a reference time providing apparatus 400 for generating a time information message , The reference time (T _ref ) recorded in the time information message can not be set at the time of the fourth time point (t ₄ ). The LoRa network terminal 100 can set the time of the fourth time point t _{4 as} the correction time point T _corr of the LoRa network terminal 100 through the following Equation 1.

The principle of Equation (1) will be described as follows. Referring to FIG. 4, the reference time T _ref is a time at which the first time information request message is transmitted between the first time point t ₁ and the second time point t ₂ (Hereinafter referred to as " fifth time point t ₅ " However, the time interval between the reference time (T _ref) time is corrected by the fifth point in time because the fourth time (t ₄₎ instead of (t _5), the fourth point in time (t ₄₎ and a fifth time (t ₅₎ ( t ₄ -t ₅ ) must be added to the reference time T _ref to be set as the correction time T _corr .

Referring to FIG. 4, the value of t ₄ -t ₅ is obtained by dividing the time interval t ₄ -t ₂ between the fourth time point t ₄ and the second time point t _{2 by} the second time point t ₂ , And the time interval t ₂ -t ₅ between the fifth time point t ₅ can be obtained. Herein, when both the first time information request message and the second time information request message are received, if the reception acknowledgment message is received after the first waiting time T ₁ , the third time point t ₃ and the first time point the time interval (t ₃ -t ₁₎ between t ₁₎ is also equal to the value of t ₄ -t _2. Since the fifth time point t ₅ may exist between the first time point t ₁ and the second time point t ₂ as described above, the value of t ₂ -t ₅ is, on the average, (t ₂ -t ₁ ) / 2 which is half the time interval between the first time point t ₁ and the second time point t ₂ . The above equation (1) can be derived according to this principle.

The practical application of the time correction method according to Equation (1) as described above will be exemplified as follows. For example, when the time of the fourth time point t ₄ is 15:47:38 by the time information of the LoRa network terminal 100 before the correction, the correction time T _corr calculated by the above Equation 1 becomes 15:00 52 minutes 58 seconds, the LoRa network terminal 100 can newly set the time of the fourth time point t _{4 to} 15:52:58. That is, it means that the pre-correction time information is about 5 minutes and 20 seconds earlier than the correct time information by the standard time, and the clock of the LoRa network terminal 100 is delayed by 5 minutes and 20 seconds by the time correction.

According to an embodiment of the present invention as described above, it is possible to easily and accurately correct the time of the LoRa network terminal using only the characteristics of the LoRa network without adding an additional device to the terminal.

Combinations of each step of the flowchart and each block of the block diagrams appended to the present invention may be performed by computer program instructions. These computer program instructions may be embedded in an encoding processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus, so that the instructions, performed through the encoding processor of a computer or other programmable data processing apparatus, Thereby creating means for performing the functions described in each step of the flowchart. These computer program instructions may also be stored in a computer usable or computer readable memory capable of directing a computer or other programmable data processing apparatus to implement the functionality in a particular manner so that the computer usable or computer readable memory It is also possible for the instructions stored in the block diagram to produce a manufacturing item containing instruction means for performing the functions described in each block or flowchart of the block diagram. Computer program instructions may also be stored on a computer or other programmable data processing equipment so that a series of operating steps may be performed on a computer or other programmable data processing equipment to create a computer- It is also possible that the instructions that perform the processing equipment provide the steps for executing the functions described in each block of the block diagram and at each step of the flowchart.

Also, each block or each step may represent a module, segment, or portion of code that includes one or more executable instructions for executing the specified logical function (s). It should also be noted that in some alternative embodiments, the functions mentioned in the blocks or steps may occur out of order. For example, two blocks or steps shown in succession may in fact be performed substantially concurrently, or the blocks or steps may sometimes be performed in reverse order according to the corresponding function.

The above description is merely illustrative of the technical idea of the present invention, and various modifications and changes may be made by those skilled in the art without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be construed according to the following claims, and all technical ideas within the scope of equivalents thereof should be construed as falling within the scope of the present invention.

According to an embodiment of the present invention, the time of the LoRa network terminal can be easily and accurately corrected using only the characteristics of the LoRa network system without adding an additional device to the terminal.

10: LoRa network system
100: LoRa network terminal
200: LoRa network server
300: LoRa network base station
400: reference time providing device
410: Application server
420: external time information providing server
500: Service Manager

Claims (8)

A method for correcting time information of a LoRa network terminal connected to a LoRa network server,
The method comprising: transmitting a first time (t _1), the first time information request message to the network server LoRa;
The method comprising: receiving an acknowledgment message for the second time (t ₂₎ in the LoRa the first time that the network server is sent the information request message;
Wherein the second transmission a third time (t _3), the second time information request message after the start point in the LoRa network server;
It said method comprising four receive time (t ₄₎ in the LoRa the network server is the first reference time determined on the basis of the time of transmitting the acknowledgment message for a first time information request message (T _ref) is the recording time information message ; And
Correcting the time information of the terminal based on the reference time, the interval between the second time point and the fourth time point, and the interval between the first time point and the second time point
Time correction method. The method according to claim 1,
_Wherein the correcting step corrects the time at the fourth time point based on an expression of "T _corr = T _ref + (t ₄ -t ₂ ) + (t ₂ -t ₁ ) / 2" (T _corr ) < / RTI >
Time correction method. The method according to claim 1,
Wherein the first time information request message is transmitted from the LoRa network server to a reference time providing apparatus having standard time information when the LoRa network server sends an acknowledgment message for the first time information request message,
The time information message is generated by the reference time providing apparatus that has received the first time information request message and transmitted to the LoRa network server,
Wherein the time information message includes a time when the reference time providing device has received the first time information request message from the LoRa network server based on the standard time information,
Time correction method. A terminal connected to a LoRa network server through a LoRa (Long Range) network,
A communication unit for performing data transmission to the LoRa network server and data reception from the LoRa network server;
The first time information request message is transmitted to the LoRa network server through the communication unit at a first time point t ₁ and the reception acknowledgment message for the first time information request message sent from the LoRa network server is transmitted to the LoRa network server at a second time point receiving a (t ₂₎ through the communication unit, and the second time information request message for the third time after the second point in time (t ₃₎ sent to the LoRa network server via the communication unit, and the LoRa network server A control unit receiving at the fourth time point (t ₄ ) a time information message in which a predetermined reference time (T _ref ) is recorded based on a time point at which the mobile station transmits an acknowledgment message for the first time information request message; And
And a correction unit that corrects the time information of the terminal based on the reference time, the interval between the second time point and the fourth time point, and the interval between the first time point and the second time point
LoRa network terminal. 5. The method of claim 4,
The correcting unit corrects the time at the fourth time point based on an expression of "T _corr = T _ref + (t ₄ -t ₂ ) + (t ₂ -t ₁ ) / 2" Tcorr)
LoRa network terminal. 5. The method of claim 4,
Wherein the first time information request message is transmitted from the LoRa network server to a reference time providing apparatus having standard time information when the LoRa network server sends an acknowledgment message for the first time information request message,
The time information message is generated by the reference time providing apparatus that has received the first time information request message and transmitted to the LoRa network server,
Wherein the time information message includes a time when the reference time providing device has received the first time information request message from the LoRa network server based on the standard time information,
LoRa network terminal. 13. A program stored in a computer-readable medium for performing the respective steps according to the method of any one of claims 1 to 3. A computer-readable recording medium having recorded thereon a program for carrying out the steps according to the method according to any one of claims 1 to 3.

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