KR20100062786A - Time synchronized system and time synchronization method in the next generation convergence network - Google Patents

Abstract

PURPOSE: A time synchronizing system and a time synchronizing method in a fixed integration network are provided to receive time information and delay time information between a ToD gateway and a terminal using only a synchronizing message or a general data message and an ACK message. CONSTITUTION: A delay requesting apparatus transmits a delay requiring message of data frame form to a delay response apparatus(S31). The delay response apparatus transmits an ACK message about the delay requiring message to the delay requesting apparatus(S32). The delay requesting apparatus transmits a synchronizing message to the delay response apparatus(S33). The delay response apparatus transmits the ACK message about the synchronizing message to the delay requesting apparatus(S34). The delay requesting apparatus transmits the synchronizing message including time information to the delay response apparatus(S35). The delay response apparatus transmits the synchronizing message including the time information to the delay requesting apparatus(S36).

Description

Time Synchronization System and Time Synchronization Method in Wired / Wireless Integrated Network {TIME SYNCHRONIZED SYSTEM AND TIME SYNCHRONIZATION METHOD IN THE NEXT GENERATION CONVERGENCE NETWORK}

The present invention relates to a time synchronization system and a time synchronization method in a wired / wireless converged network. More particularly, the present invention relates to a time between day gateway and a terminal using only a synchronization message or a general data message and an ACK message thereof. The present invention relates to a technique for performing time synchronization more quickly and simply by transmitting and receiving time information and delay time information.

The present invention is derived from the research conducted as part of the IT growth engine technology development project of the Ministry of Knowledge Economy and the Ministry of Information and Communication Research and Development. [Task management number: 2007-S-012-02, Title: Development of multimedia convergence network on-chip technology] .

Synchronizing visual information is required in various fields, and thus a method of synchronizing visual information has been provided as a standard. A representative time synchronization protocol that can be used in a wired / wireless converged network is the PTP (Precision Time Protocol) standardized by the IEEE.

1 is a diagram illustrating a time synchronization process according to IEEE 1588 PTP.

According to the PTP, the master and the slave exchange time information and related messages to determine the offset and propagation delay time between the master's clock and the slave's clock, and the slave's clock is converted to the master's clock. Motivate to

Specifically, in order to determine the offset, the master periodically transmits a synchronization message SYNC (t1) to the slave (S11). At this time, the master measures the time t1 at the time of transmitting the sync message and transmits the measured time information t1 to the slave by including the measured time information t1 in the sync message.

The slave measures the time t2 at the time when the synchronization message is received, and the time information t1 included in the synchronization message SYNC (t1) received from the master and the time t2 at the time when the synchronization message is received. To calculate the offset.

However, the delay time occurs while the synchronization message is transferred from the master to the slave.

In order to measure the propagation delay time on the network, the slave transmits a delay time request message DELAY_REQ to the master (S12), and measures the time t3 at the time of transmission. The master measures the time t4 at the time when the delay time request message is received and transmits a delay time response message DELAY_RESP (t4) including the measured time information t4 to the slave (S13).

Accordingly, the slave uses the four time information t1, t2, t3, and t4 obtained through the synchronization message, the delay time request message, and the delay time response message to propagate with the offset O by the following equations (1) to (4). The delay time D can be determined. At this time, it is assumed that the propagation delay time for transferring the message from the master to the slave and the propagation delay time for transferring the message from the slave to the master are symmetrically identical to each other.

D + O = t2-t1

D-O = t4-t3

D = ((t2-t1) + (t4-t3)) / 2

O = ((t2-t1)-(t4-t3)) / 2

FIG. 2 is a diagram illustrating a message flow when the time synchronization process illustrated in FIG. 1 is applied to a wireless network. In a wireless network, in order to prevent data retransmission and to increase data transmission rate, when a data transmitting apparatus transmits a data frame to the data receiving apparatus, the data receiving apparatus automatically generates an ACK message for the received data frame to the data transmitting apparatus. send.

Therefore, as shown in FIG. 2, when the delay request device transmits a request message in the form of a data frame to the delay response device (S21), the second layer of the delay response device automatically transmits an ACK message in the form of a control frame. It generates and transmits to the delay request device (S22). Thereafter, when the delay response device transmits a response message (Response (t3-t2)) having a data frame format including time information t3-t2 to the delay request device (S23). An ACK message in a control frame format is automatically generated and transmitted to the delay response device (S24). Subsequently, the delay request apparatus propagates by using Equation 3 using time information t3-t2 included in the response message, time information t1 at the time of transmitting the request message, and time information t4 at the time of receiving the response message. The delay time D1 may be determined. Then, for time synchronization between the delay response device and the delay request device, the delay request device transmits a synchronization message Sync (t5 + D1) including the propagation delay time D1 determined as described above to the delay response device ( S25), or the delay response device transmits a synchronization message Sync (t6) including the time information t6 at the time of transmission to the delay request device (S27) so that the delay request device receives the propagation delay time D1 and received. By using the time information t6 included in the synchronization message, time synchronization can be performed.

As described above, according to the related art for time synchronization, a plurality of messages need to be transmitted and received, such as a synchronization message, a delay time request message, and a response message, in order to measure a delay time. Big.

In addition, since the processing of the message in the data frame format is required for transmission of time information, the time required for measuring the delay time becomes long, and in particular, there is a problem in that an error in measuring the delay time required in the wireless network becomes large.

Accordingly, the present invention is to solve the above problems of the prior art, time information and delay time information between the ToD (Time of Day) gateway and the terminal using only a synchronization message (Sync) or a general data message and the ACK message thereof. The present invention provides a time synchronization system and a time synchronization method in a wired / wireless integrated network that can perform time synchronization more quickly and simply by transmitting and receiving.

In a time synchronization system according to an embodiment of the present invention for achieving the above object, the time server and the ToD gateway is connected through a wired network, the time in the wired / wireless integrated network where the ToD gateway and the terminal is connected through a wireless network A synchronization system, comprising: a time server receiving standard time information from a GPS receiver to maintain a standard time and providing time information for time synchronization to the terminal through the ToD gateway; And transmitting a request message for measuring a delay time to the terminal, receiving an ACK message including time information from the terminal, calculating a delay time with the terminal from the time information included in the ACK message, and calculating the delay. And a ToD gateway for transmitting a synchronization message including time and time information of a transmission time point to the terminal.

The time synchronization system transmits an ACK message including time information to the ToD gateway with respect to the request message for delay time measurement received from the ToD gateway, and includes a delay included in the synchronization message received from the ToD gateway. The apparatus may further include a terminal for performing time synchronization with the ToD gateway using time and time information.

The time information included in the ACK message may include the first time information when the terminal receives the request message, the second time information when the terminal transmits the ACK message, or the second time information. Time information corresponding to a value obtained by subtracting the first time information is included.

In addition, the request message for measuring the delay time may be composed of a synchronization message or a general data frame.

In addition, the ToD gateway converts a frame format of a message transmitted between a wired network and a wireless network, delays measurement error occurring in a wired network path between the time server and the ToD gateway, and synchronizes time at the ToD gateway. A function of correcting a delay measurement error required for processing and a delay measurement error occurring in a wireless network path between the ToD gateway and the terminal is performed.

On the other hand, the time synchronization method according to another embodiment of the present invention for achieving the above object, in order to perform the time synchronization between the delay request device and the delay response device in a wired / wireless integrated network, at the delay request device side, Transmitting a request message for delay time measurement to a delay response device; Receiving an ACK message including time information from the delay response device; Calculating a delay time between the delay request device and the delay response device by using the time information included in the ACK message; And transmitting a synchronization message including a calculated delay time and time information of a transmission time point to the delay response device, and receiving a synchronization message including time information of a time point of transmission from the delay response device. ; And performing time synchronization with the delay response device by using the time information included in the received synchronization message and the calculated delay time information.

Also, in order to perform time synchronization between the delay request device and the delay response device in the wired / wireless integrated network, the delay response device includes time information on a request message for measuring delay time received from the delay request device. Transmitting an ACK message to the delay requesting device; Receiving a synchronization message including time information at the time of transmission from the delay request device and delay time information between the delay request device and the delay response device; And performing time synchronization with the delay request device by using the time information and delay time information included in the received sync message, and transmitting the sync message including time information at the time of transmission to the delay request device. The method may further include transmitting.

The time information included in the ACK message may include first time information when the delay response device receives the request message, second time information when the delay response device transmits the ACK message, or the second time information. Time information corresponding to a value obtained by subtracting the first time information from time information is included.

In addition, the request message for measuring the delay time may be composed of a synchronization message or a general data frame.

According to the present invention, the number of messages transmitted and received to measure the delay time between the ToD gateway and the terminal is reduced, thereby reducing the power consumed for time synchronization.

In addition, the synchronization process may be simplified by transmitting the calculated delay time information along with the time information in a synchronization message.

In addition, as the time information is transmitted using the response message, the response time is reduced, thereby reducing the time required for the synchronization process and reducing the error of the delay time measurement.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. However, in describing the preferred embodiment of the present invention in detail, if it is determined that the detailed description of the related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. In addition, the same reference numerals are used throughout the drawings for parts having similar functions and functions.

In addition, throughout the specification, when a part is 'connected' to another part, it is not only 'directly connected' but also 'indirectly connected' with another element in between. Include. In addition, the term 'comprising' of an element means that the element may further include other elements, not to exclude other elements unless specifically stated otherwise.

3A and 3B illustrate a time synchronization process according to the present invention.

Referring to FIG. 3A, when the delay request apparatus transmits a delay request message having a data frame format to the delay response apparatus (S31), the delay response apparatus generates an ACK message for the delay request message and transmits the delay request apparatus to the delay request apparatus (S32). ). In this case, the ACK message includes the time information t2 at the time when the delay response device receives the delay request message and the time information t3 at the time when the ACK message is transmitted, or the difference value t3-t2 of the time information. It includes.

In other words, the delay request apparatus merely receives an ACK message for the delay request message without separately receiving a response message in the form of a data frame from the delay response apparatus, thereby providing time information ((t2, t3) necessary for determining the delay time. Or t3-t2). Accordingly, the delay request apparatus includes time information included in the ACK message and time information known inside the delay request apparatus, that is, time information t1 at the time when the delay request apparatus transmits the delay request message and the ACK message from the delay response apparatus. The delay time D2 may be calculated using the time information t4 at the time point of receiving the signal.

Thereafter, the delay request apparatus performs time synchronization with the delay response apparatus by using the delay time D2 calculated as described above. To this end, the delay request apparatus transmits a synchronization message Sync (t5 + D2) including the calculated delay time D2 and time information t5 at the time of transmitting the synchronization message to the delay response apparatus (S33). . The delay response device performs time synchronization with the delay request device by adjusting its time to t5 + D2 using the delay time D2 and the time information t5 included in the received synchronization message. In addition, when the delay response device transmits an ACK message (ACK (t7-t6)) for the synchronization message Sync (t5 + D2) to the delay request device (S34), the delay request device is delayed as described above. (D3) can be calculated. Accordingly, the delay request device transmits the synchronization message Sync (t9 + D3) including the calculated delay time D3 and time information t9 at the time of transmitting the synchronization message to the delay response device (S35). The delay response device may be configured to perform time synchronization with the delay request device.

On the other hand, when the delay response device intends to perform time synchronization by transmitting a synchronization message to the delay request device, the delay response device includes a time information t10 at the time of transmitting the sync message (Sync (t10)). Is transmitted to the delay request device (S36), the delay request device delays by adjusting its time to t10 + D3 using the calculated delay time D3 and the time information t10 included in the received synchronization message. Perform time synchronization with the response device.

Meanwhile, according to the present invention, time synchronization may be performed between the delay request device and the delay response device by transmitting general data instead of a specific synchronization message for performing time synchronization.

Referring to FIG. 3B, even when the delay request device transmits a synchronization message or general data to the delay response device (S41), the second layer of the delay response device automatically generates an ACK message for the received data. The delay is transmitted to the device (S42). Therefore, if such an ACK message includes the time information as described above with reference to FIG. 3A, the time synchronization process according to the present invention can be applied to transmission of general data.

Specifically, the delay request apparatus measures and stores time information at the time of transmitting general data to the delay response device and time information at the time of receiving the ACK message for the data. Meanwhile, the delay response device requests a delay of an ACK message including time information (Δt) obtained by subtracting the time of receiving data from the delay request device from the time of transmitting the ACK message for the data received from the delay request device. Send to the device.

Therefore, the delay request device can calculate the delay time using the time information Δt included in the ACK message and the time information stored inside the delay request device, and time synchronization with the delay response device using the calculated delay time. It becomes possible to perform (S43).

As such, the delay request apparatus can measure the delay time required to perform time synchronization by transmitting general data. This method can measure the delay time even when transmitting general data rather than a message according to a protocol for synchronization, such as a synchronization message or a delay request message, so that the delay time continuously varies according to the movement of the terminal in the wireless network. It can be usefully used to measure.

4 is a diagram illustrating a frame structure of an ACK message. FIG. 4A illustrates a frame structure of an ACK message determined by the IEEE standard. FIG. 4B is a view illustrating a frame synchronization of the present invention. It shows the frame configuration of the modified ACK message.

The ACK message shown in (a) of FIG. 4 follows the format of a control frame. That is, the ACK message according to the IEEE standard is composed of a frame control field of 2 bytes, a duration field of 2 bytes, a receiver address field of 6 bytes, and a frame check sequence (FCS) field of 4 bytes. It is composed. As such, since the general ACK message does not include a data field, in order to transmit time information using the ACK message, the frame structure of the ACK message must be modified as shown in FIG.

That is, the ACK message used in the present invention includes a ToD value field for including time information in addition to the frame control field, duration field, RA field, and FCS field of the general ACK message as shown in FIG. It is configured to further include.

The ToD value field includes time information necessary for measuring the delay time, that is, time information t2 at the time when the delay response device receives the synchronization message or data, and time information t3 at the time when the ACK message is transmitted. Or may include a difference value t3-t2 of the visual information. The ToD value field may be configured in any size (N bytes), and the time information value carried in the ToD value field may be configured in an appropriate form according to the size of the ToD value field.

5 is a block diagram of a wired / wireless integrated network to which a time synchronization process according to the present invention can be applied. The time synchronization system in the wired / wireless integrated network includes a time server 10, a ToD gateway 20, and a terminal 30. In this case, the time server 10 and the ToD gateway 20 are connected through a wired network such as, for example, a wired Ethernet, and the ToD gateway 20 and the terminal 30 are connected through a wireless network.

In order to perform time synchronization, the time server 10 and the ToD gateway 20, and the ToD gateway 20 and the terminal 30 are set to have a hierarchical structure of a master and a slave or a delay request device and a delay response device. .

The time server 10 receives standard time information from a GPS receiver or the like, maintains the standard time, and provides time information for time synchronization to the terminal 30 through the ToD gateway 20.

ToD gateway 20 serves to connect a wired network and a wireless network. In detail, the ToD gateway 20 converts a frame format of data transmitted through a wired network into a frame format suitable for the wireless network and the terminal 30. In addition, the ToD gateway 20 may include a delay measurement error occurring in a wired network path between the time server 10 and the ToD gateway 20, a delay measurement error required to process time synchronization at the ToD gateway 20, and It has a function of correcting a delay time measurement error or the like occurring in the wireless network path between the ToD gateway 20 and the terminal 30.

In the wired / wireless integrated network shown in FIG. 5, the time server 10 and the ToD gateway 20 perform time synchronization using a time synchronization protocol such as NTP (Network Time Protocol) or PTP, and the ToD gateway 20 The terminal 30 performs time synchronization according to the time synchronization process according to the present invention shown in FIG. 3A or 3B.

FIG. 6 is a diagram illustrating an embodiment in which the time synchronization process of the present invention is applied to the wired / wireless integrated network shown in FIG. 5.

First, the time server 10 and the ToD gateway 20 perform time synchronization according to the PTP. Specifically, when the time server 10 transmits a synchronization message Sync (t1) including the time information t1 at the time of transmitting the message to the ToD gateway 20 (S61), the ToD gateway 20 After the time information t1 included in the synchronization message is extracted (S62), the frequency scale factor is updated (S63).

Thereafter, when the ToD gateway 20 transmits the delay time request message Delay_Req to the time server 10 (S64), the time server 10 sends the time information t4 at the time when the delay time request message is received. The delay time response message Delay_Resp (t4) is transmitted to the ToD gateway 20 (S65).

The ToD gateway 20 extracts the time information t4 included in the received delay time response message (S66), and then uses the time information of the time server 10 by using the time information at the time of transmission and reception of the synchronization message and the delay time request message. The delay time D1 and the offset O1 between the ToD gateway 20 are calculated (S67), and time synchronization between the time server 10 and the ToD gateway 20 is performed.

Meanwhile, the ToD gateway 20 and the terminal 30 perform time synchronization according to the time synchronization process according to the present invention. Specifically, when the ToD gateway 20 transmits a synchronization message Sync (t5) to the terminal 30 (S68), the terminal 30 receives time information t6 and an ACK message at the time when the synchronization message is received. The ACK message including the time information t7 at the time of transmitting the signal or the difference values t7-t6 of the time information is transmitted to the ToD gateway 20 (S69).

Thereafter, the ToD gateway 20 extracts time information (t6, t7) or t7-t6 included in the ACK message received from the terminal 30 (S70), and then the ToD gateway 20 and the terminal 30. Calculate the delay time (D2) between (S71).

Thereafter, the ToD gateway 20 transmits a synchronization message Sync (t9, D2) including the calculated delay time D2 and time information t9 at the time of transmitting the synchronization message to the terminal 30 ( S72, the terminal 30 performs time synchronization with the ToD gateway 20 using the received synchronization message. In addition, the terminal 30 transmits an ACK message including time information to the ToD gateway 20 as described above with respect to the received synchronization message.

Therefore, the ToD gateway 20 can continuously calculate the delay time between the ToD gateway 20 and the terminal 30 by using the time information included in the ACK message received from the terminal 30, thereby making it necessary. By transmitting a synchronization message including the calculated delay time information to the terminal 30, time synchronization between the ToD gateway 20 and the terminal 30 may be performed.

As such, in this embodiment, the time synchronization process with the time server 10 is terminated at the ToD gateway 20, and the terminal 30 does not directly perform time synchronization with the time server 10, but the time server 10. Time synchronization is performed according to the time synchronization process according to the present invention and the ToD gateway 20 synchronized with the "

FIG. 7 is a diagram illustrating another embodiment in which the time synchronization process of the present invention is applied to the wired / wireless integrated network shown in FIG. 5.

In the present embodiment, unlike the embodiment described above with reference to FIG. 6, the time synchronization process with the time server 10 is transmitted to the terminal 30 without being terminated at the ToD gateway 20.

The time server 10 and the ToD gateway 20 perform time synchronization according to the PTP. The ToD gateway 20 does not perform all the time synchronization processes according to the PTP, but the terminal transmits and receives a message transmitted and received in the synchronization process according to the PTP. By transmitting to 30, time synchronization between the time server 10 and the terminal 30 can be performed. Meanwhile, the delay time between the ToD gateway 20 and the terminal 30 may be calculated by the time synchronization process according to the present invention.

Specifically, when the time server 10 transmits a synchronization message Sync (t1) including the time information t1 at the time of transmitting the message to the ToD gateway 20 (S81), the ToD gateway 20 The received synchronization message is transmitted to the terminal 30 (S82).

On the other hand, the terminal 30 includes time information t2 at the time of receiving the synchronization message and time information t3 at the time of transmitting the ACK message, or provides a difference value t3-t2 of the time information. An ACK message is transmitted to the ToD gateway 20 (S83).

The ToD gateway 20 extracts time information ((t2, t3) or t3-t2) included in the ACK message received from the terminal 30 (S84), and then between the ToD gateway 20 and the terminal 30. The delay time D1 is calculated (S85).

Thereafter, when the terminal 30 transmits the delay time request message Delay_Req to the ToD gateway 20 (S86), the ToD gateway 20 transmits the received delay time request message to the time server 10 (S87). ).

Thereafter, the time server 10 transmits a delay time response message Delay_Resp (t6) including the time information t6 at the time of receiving the delay time request message to the ToD gateway 20 (S88), and the ToD gateway. 20 transmits the received delay time response message to the terminal 30 (S89).

The terminal 30 may calculate the delay time D2 and the offset O2 between the time server 10 and the terminal 30 by using the time information included in the received delay time response message (S90).

Thereafter, when the time server 10 transmits a synchronization message including time information tn at the time when the synchronization message is transmitted to the ToD gateway 20 (S91), the ToD gateway 20 calculates a delay time calculated in advance. D1) is further included in the synchronization message and transmitted to the terminal 30 (S92). Accordingly, the terminal 30 performs time synchronization with the time server 10.

In the above-described process, the ToD gateway 20 should serve to connect heterogeneous networks. Specifically, the ToD gateway 20 should appropriately convert the frame format of the message to be delivered. In addition, a delay measurement error occurring in a wired network path between the time server 10 and the ToD gateway 20, a delay measurement error required to process time synchronization in the ToD gateway 20, and the ToD gateway 20 The delay time measurement error occurring in the wireless network path between the terminal 30 should be calculated, and the error values should be reflected in the time information provided by the time server 10.

The present invention is not limited by the above-described embodiment and the accompanying drawings. It will be apparent to those skilled in the art that the present invention may be substituted, modified, and changed in accordance with the present invention without departing from the spirit of the present invention.

1 is a view showing a time synchronization process according to IEEE 1588 PTP;

2 is a diagram illustrating a message flow when the time synchronization process illustrated in FIG. 1 is applied to a wireless network.

3A and 3B illustrate a time synchronization process according to the present invention;

4 is a diagram illustrating a frame structure of an ACK message;

5 is a configuration diagram of a wired / wireless integrated network to which a time synchronization process according to the present invention can be applied;

6 is a view showing an embodiment when the time synchronization process of the present invention is applied to the wired and wireless integrated network shown in FIG.

FIG. 7 is a diagram illustrating another embodiment in which the time synchronization process of the present invention is applied to the wired / wireless integrated network shown in FIG. 5.

* Description of the symbols for the main parts of the drawings *

10: time server

20: ToD Gateway

30: terminal

Claims (11)

In order to perform time synchronization between a delay request device and a delay response device in a wired / wireless integrated network, at the delay request device side, Transmitting a request message for delay time measurement to the delay response device; Receiving an ACK message including time information from the delay response device; Calculating a delay time between the delay request device and the delay response device by using the time information included in the ACK message; And And transmitting a synchronization message including the calculated delay time and time information of the transmission time point to the delay response device. The method of claim 1, Receiving a synchronization message including time information at the time of transmission from the delay response device; And And performing time synchronization with the delay response device by using the time information included in the received synchronization message and the calculated delay time information. In the delay response device side, to perform time synchronization between the delay request device and the delay response device in a wired / wireless converged network, Transmitting an ACK message including time information to the delay request device with respect to the request message for delay time measurement received from the delay request device; Receiving a synchronization message including time information at the time of transmission from the delay request device and delay time information between the delay request device and the delay response device; And And performing time synchronization with the delay request device by using the time information and the delay time information included in the received synchronization message. The method of claim 3, wherein And transmitting the synchronization message including the time information at the time of transmission to the delay request device. The method according to claim 1 or 3, Time information included in the ACK message, The first time information when the delay response device receives the request message, the second time information when the delay response device transmits the ACK message, or the first time information minus the second time information. A time synchronization method in a wired / wireless integrated network, comprising time information corresponding to a value. The method according to claim 1 or 3, The request message for measuring the delay time, A time synchronization method in a wired / wireless converged network comprising a synchronization message or a general data frame. A time synchronization system in a wired / wireless integrated network in which a time server and a ToD gateway are connected through a wired network, and the ToD gateway and a terminal are connected through a wireless network. A time server receiving standard time information from a GPS receiver to maintain a standard time and providing time information for time synchronization to the terminal through the ToD gateway; And Transmitting a request message for measuring a delay time to the terminal, receiving an ACK message including time information from the terminal, calculating a delay time with the terminal from the time information included in the ACK message, and calculating the calculated delay time And a ToD gateway for transmitting a synchronization message including time information at the time of transmission to the terminal. The method of claim 7, wherein The ACK message including time information is transmitted to the ToD gateway with respect to the request message for measuring the delay time received from the ToD gateway, and the delay time and time information included in the synchronization message received from the ToD gateway is used. A time synchronization system in a wired / wireless integrated network further comprising a terminal for performing time synchronization with the ToD gateway. The method of claim 7, wherein Time information included in the ACK message, Corresponds to a value obtained by subtracting the first time information from the first time information when the terminal receives the request message, the second time information when the terminal transmits the ACK message, or the second time information. A time synchronization system in a wired / wireless integrated network, comprising visual information. The method of claim 7, wherein The request message for measuring the delay time, A time synchronization system in a wired / wireless converged network comprising a synchronization message or a general data frame. The method of claim 7, wherein The ToD gateway converts a frame format of a message transmitted between a wired network and a wireless network, and processes a delay measurement error occurring in a wired network path between the time server and the ToD gateway, and time synchronization at the ToD gateway. A time synchronization system in a wired / wireless integrated network, comprising correcting a delay measurement error and a delay measurement error occurring in a wireless network path between the ToD gateway and the terminal.

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