WO2012055360A1

WO2012055360A1 - Method for time synchronization and device and system thereof

Info

Publication number: WO2012055360A1
Application number: PCT/CN2011/081373
Authority: WO
Inventors: 谢雷; 余芳; 徐骁
Original assignee: 华为技术有限公司
Priority date: 2010-10-27
Filing date: 2011-10-27
Publication date: 2012-05-03
Also published as: CN102457371B; CN102457371A

Abstract

A method for time synchronization and device and system thereof in the embodiment of the present invention are provided. Wherein, the method for time synchronization includes the following steps: a master clock device transmits a first time synchronization message to a slave clock device, and obtains a time T1 at which the first time synchronization message is transmitted through a radio frequency; the master clock device transmits a second time synchronization message which carries a time stamp of T1 to the slave clock device; the master clock device receives a third time synchronization message transmitted from the slave clock device, and obtains a time T4 at which the third synchronization message is received by an air interface physical layer; the master clock device transmits a forth time synchronization message which carries a time stamp of T4 to the slave clock device, so that the slave clock device calculates the clock offset between the slave clock device and the master clock device according to T1 and T4, and modifies the local clock of the slave clock device according to the calculated clock offset. The embodiment of the present invention is in favor of improving the time synchronization precision of the master and the slave clock devices.

Description

Time synchronization method and related equipment and system This application claims priority to Chinese patent application filed on October 27, 2010, the Chinese Patent Office, Application No. 201010527699.9, entitled "Time Synchronization Method and Related Equipment and System" The entire contents of which are incorporated herein by reference.

Technical field

The present invention relates to the field of communications, and in particular, to a time synchronization method and related devices and systems. Background technique

At present, with the gradual completion of the transformation of the core network protocol (IP, Internet Protocol) of the communication network, the IP of the wireless access network will become the key to the evolution of the entire mobile network to an all-IP (ALL-IP) network. In the process of realizing the IP access of the wireless access network, the time synchronization problem is a problem that needs to be studied and solved. Time synchronization means that the absolute time between different systems is the same. For example, in a communication system, each system has an internal time, that is, a local clock, which is managed by the clock device of the system, due to the locality of each system. The clocks are all running independently, so the local clocks of the various systems are not necessarily the same. In a distributed network environment, if there is no uniform and accurate time standard, the system will be difficult to coordinate the subsystems normally. Operation, time synchronization technology is a technology that controls the time deviation between different systems within a certain range.

In order to achieve time synchronization between network devices, the IEEE, Institute of Electrical and Electronics Engineers -1588 standard was introduced in the network. IEEE-1588 defines the Precision Time Protocol (PTP). Time synchronization of other clock devices in the wired network with other clock devices based on the IEEE-1588 standard.

It has been found that when the time synchronization mechanism of the master-slave clock device in the existing wired network is applied to the wireless network, the time synchronization accuracy between the master and slave clock devices is usually low. Summary of the invention

Embodiments of the present invention provide a time synchronization method and related device and system, which are used to improve a main Time synchronization accuracy from the clock device.

To solve the above technical problem, the embodiment of the present invention provides the following technical solutions:

A time synchronization method, including:

The master clock device sends the first time synchronization message to the slave clock device, and acquires the time when the first time synchronization message is sent through the radio frequency.

The master clock device sends a second time synchronization message to the slave clock device, and carries the time stamp of the above 1\ in the second time synchronization message;

The master clock device receives the third time synchronization message sent by the slave clock device, and acquires the time τ ₄ when the air interface physical layer receives the third time synchronization message;

The master clock device sends a fourth time synchronization message to the slave clock device, and carries the time stamp of the Τ ₄ in the fourth time synchronization message, so that the slave clock device calculates the slave clock device according to the foregoing 1\ and τ ₄ And a clock offset of the master clock device, and correcting the local clock of the slave clock device according to the calculated clock offset.

A time synchronization method, including:

Receiving, by the clock device, the first time synchronization message sent by the master clock device, and acquiring the time τ ₂ at which the air interface physical layer receives the first time synchronization message;

Receiving, by the clock device, the second time synchronization message sent by the master clock device, and acquiring the timestamp of the first time synchronization message carrying the 1\, wherein the first clock is sent by the master clock device by using the radio frequency. The moment of synchronizing the message;

Transmitting, by the clock device, the third time synchronization message to the master clock device, and acquiring the time τ ₃ sent by the third time synchronization message through the radio frequency;

Receiving, by the clock device, a fourth time synchronization message sent by the master clock device, and acquiring a timestamp of τ ₄ carried in the fourth time synchronization message, where the τ ₄ is received by the master clock device on the physical layer of the air interface The time to the third time synchronization message described above;

The slave clock device calculates a clock offset of the slave clock device and the master clock device according to the above 1\, τ ₂ , τ ₃ and τ ₄ ;

The slave clock device corrects the local clock of the slave clock device based on the calculated clock offset.

A master clock device, including: a transceiver module, configured to send a first time synchronization message to the slave clock device;

An acquiring module, configured to acquire a time when the transceiver module sends the first time synchronization message by using a radio frequency

The transceiver module is further configured to send the second time synchronization message to the slave clock device, and carry the time stamp of the above 1\ in the second time synchronization message;

The transceiver module is further configured to receive a third time synchronization message sent by the slave clock device.

The obtaining module is further configured to acquire, when the transceiver module sends the third synchronization message, the time τ ₄ at which the air interface physical layer receives the third time synchronization message;

The transceiver module is further configured to send a fourth time synchronization message to the slave clock device, and carry the time stamp of the τ ₄ in the fourth time synchronization message; so that the slave clock device calculates the foregoing according to the foregoing 1 and τ ₄ The clock offset of the slave clock device from the clock device and the master clock device is corrected, and the local clock of the slave clock device is corrected according to the calculated clock offset.

A slave clock device, including:

a transceiver module, configured to receive a first time synchronization message sent by the master clock device, and an acquiring module, configured to acquire, according to the first time synchronization message received by the transceiver module, a time τ ₂ when the air interface physical layer receives the first time synchronization message ;

The transceiver module is further configured to receive a second time synchronization message sent by the primary clock device, where the second time synchronization message carries a time stamp of 1\;

The acquiring module is configured to receive, by using the second synchronization message, the timestamp carried in the second time synchronization message, where the first time is a time when the primary clock device sends the first time synchronization message by using a radio frequency. ;

The transceiver module is further configured to send a third time synchronization message to the master clock device; the acquiring module is further configured to: when the transceiver module sends the third time synchronization message, acquire the time τ ₃ sent by the third synchronization message by using the radio frequency;

The transceiver module is further configured to receive a fourth time synchronization message sent by the master clock device, and obtain a timestamp of τ ₄ carried in the fourth time synchronization message, where the τ ₄ is the air interface physics of the master clock device. a time when the third time synchronization message is received on the layer; the processing module is configured to calculate the slave according to 1\, τ ₂ , τ ₃ and τ ₄ acquired by the acquiring module The clock offset of the clock device from the above-mentioned master clock device;

And a correction module, configured to correct the local clock of the slave clock device according to the clock offset calculated by the processing module.

A time synchronization system, including:

a master clock device, configured to send a first time synchronization message to the slave clock device, and obtain a second time synchronization message sent to the slave clock device by using the time when the first time synchronization message is sent by using the radio frequency, and in the second time synchronization message Carrying the timestamp of the above 1\; receiving the third time synchronization message sent by the slave clock device, and acquiring the time τ ₄ when the air interface physical layer receives the third time synchronization message; sending the fourth time to the slave clock device Synchronizing the message, and carrying the time stamp of the above τ ₄ in the fourth time synchronization message;

The slave clock device is configured to receive the first time synchronization message sent by the master clock device, and obtain the time τ ₂ when the air interface physical layer receives the first time synchronization message, and receive the second time synchronization message sent by the master clock device. And obtaining the timestamp of the time 1\ carried in the second time synchronization message, where 1\ is the time when the primary clock device sends the first time synchronization message by using the radio frequency; and sending the third time synchronization message to the primary clock device. And acquiring the time τ ₃ sent by the third time synchronization message by using the radio frequency; receiving the fourth time synchronization message sent by the master clock device, and acquiring the time stamp of the time τ ₄ carried in the fourth time synchronization message, τ ₄ is a time when the master clock device receives the third time synchronization message on the air interface physical layer; and calculates a clock offset between the slave clock device and the master clock device according to the above τ\, τ ₂ , τ ₃ and τ ₄ Correction of the local clock of the above slave clock device based on the calculated clock offset.

As can be seen from the above technical solutions, the embodiments of the present invention have the following advantages:

In the embodiment of the present invention, the master-slave clock device acquires the time when the time synchronization message is sent by the radio frequency (RF, Rad io Frequency) and the time when the physical layer of the air interface receives the time synchronization message, as the time of sending and receiving the time synchronization message, thereby The influence of the delay and jitter of the processing such as physical layer modulation and demodulation on the accuracy of acquiring the time of sending and receiving the time synchronization message can be eliminated, and the accuracy of the time of sending and receiving the time synchronization message is improved, and the acquisition is utilized. The higher accuracy of the time synchronization message transmission and reception time information, the time synchronization of the master-slave clock device, can improve the time synchronization accuracy of the master-slave clock device.

DRAWINGS 1 is a schematic flow chart of a time synchronization method in the prior art;

FIG. 2 is a schematic flowchart of another embodiment of a time synchronization method according to an embodiment of the present invention; FIG. 3 is a schematic flowchart of another embodiment of a time synchronization method according to an embodiment of the present invention; FIG. A schematic flow diagram of another embodiment of a time synchronization method;

FIG. 4 is a schematic diagram of a time-frequency structure of a 0.5 millisecond time slot in an LTE system according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of a manner of acquiring a time for sending or receiving a time synchronization message by using scheduling information or time-frequency resource information according to an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of another manner of obtaining, by using scheduling information or time-frequency resource information, a time for transmitting or receiving a time synchronization message according to an embodiment of the present disclosure;

FIG. 5-a is a schematic flow chart of another embodiment of a time synchronization method according to an embodiment of the present invention;

FIG. 5 is a schematic diagram of a hardware recording manner according to an embodiment of the present disclosure;

FIG. 5 is a schematic diagram of another hardware recording manner according to an embodiment of the present disclosure;

FIG. 5-d is a schematic diagram of another hardware recording manner according to an embodiment of the present disclosure;

FIG. 6 is a schematic structural diagram of a master clock device according to an embodiment of the present disclosure;

FIG. 7 is a schematic structural diagram of a slave clock device according to an embodiment of the present disclosure;

FIG. 8 is a schematic structural diagram of a time synchronization system according to an embodiment of the present invention. detailed description

Embodiments of the present invention provide a time synchronization method and related device and system for improving time synchronization accuracy of a master-slave clock device.

The technical solutions in the embodiments of the present invention will be clearly and completely described in the following with reference to the accompanying drawings in the embodiments of the present invention. It is an embodiment of the invention, but not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of the present invention.

The basic principle of realizing time synchronization between devices is to set a system default in the communication system. It is a master clock device, and other devices are slave clock devices. A time synchronization message carrying a time stamp (including a time synchronization message, a PTP message following a message, and a delayed response message) is transmitted between the master clock device and the slave clock device, and the time information described by the clock device through the time stamp. Calculating the clock offset between the master clock device and the slave clock device, and correcting the local clock of the slave clock device according to the calculation result, thereby realizing time synchronization between the slave clock device and the master clock device.

Referring to Figure 1, in the existing wired network, the specific process of time synchronization between the master and slave clock devices can be:

XI, the master clock device sends time synchronization to the slave clock device, and measures the exact time when the Sync message leaves the application layer.

X2, measuring the accurate time t _{2 of the} received Sync message from the clock device to its application layer;

X3. The master clock device sends a follow message to the Follow_up message after sending the Sync message, and carries the timestamp in the Follow_up message;

! X4, obtaining t Follow_up by receiving the packets from the time stamp clock device; transmitting a clock from the master clock device to device Delay_Req delay request message, and measuring the exact moment Delay_Req packet leaves the application _{layer. 3} t;

X5, when the master clock device receives the Delay_Req 4 message, measuring the exact time t ₄ that the Delay_Req message reaches its application layer;

X6, the master clock device to the slave clock device transmits a response packet delay Delay_Resp, ₄ and carry the time stamp t Delay_Resp message, acquires a time stamp of t ₄ the slave clock device by receiving the packet Delay_Resp;

X7, the slave clock device calculates the clock offset from the master clock device according to the above t _l t ₂ , t ₃ and t ₄ , and corrects the local clock according to the result of the final calculation, thereby implementing the master-slave clock device. Time synchronization.

The inventor's research and practice have found that the time synchronization message sent by the application layer of the sender (primary clock device or slave clock device) needs to be processed by the physical layer after being modulated, and then transmitted through the RF through the physical layer air interface. Similarly, When the receiving end (slave device or master clock device) receives the time synchronization message from the physical layer air interface, it also needs to go to the application layer after the physical layer undergoes demodulation and the like. The processing and demodulation of the physical layer will bring a certain delay and jitter to the transmission of the time synchronization cancellation. The delay and jitter are related to the speed of the baseband processing, and The difference in the downlink mechanism may lead to the asymmetry of the uplink and downlink processing delay. In the existing master-slave clock device time synchronization mechanism, the sending end usually takes the time when the time synchronization message leaves its application layer as the sending time of the time synchronization message, and the receiving end usually takes the time synchronization message to reach the application layer. As the receiving moment of the time synchronization message, the delay of the time synchronization message transmission or reception and the asymmetry of the jitter caused by the adjustment and demodulation processing of the physical layer of the master-slave clock device will greatly affect the main Time synchronization accuracy from the clock device.

The time synchronization method in the embodiment of the present invention will be described below from the perspective of the master clock device.

The time synchronization method in the embodiment of the present invention may include: the primary clock device sends a first time synchronization message to the slave clock device, and acquires a time when the first time synchronization message is sent by the RF. The master clock device sends the message to the slave clock device. a time synchronization message, and carrying a timestamp of 1\ in the second time synchronization message; the master clock device receives the third time synchronization message sent by the slave clock device, and acquires the third time synchronization received by the air interface physical layer The time τ _{4 of the} message; the master clock device sends a fourth time synchronization message to the slave clock device, and carries a time stamp of τ ₄ in the fourth time synchronization message.

Please refer to Figure 2, the specific steps may include:

201. The master clock device sends a first time synchronization message to the slave clock device.

When time synchronization is required, the default primary clock device periodically sends a unique first time synchronization message in the form of multicast according to a preset interval (default is 2 seconds), such as a time synchronization message. Sync, all in the default primary clock device network segment, and the slave clock device with the same domain as the primary clock device can receive the above first time synchronization message.

It should be noted that, for convenience of description, the embodiment of the present invention only describes the interaction between a slave clock device and the master clock device. It can be understood that the interaction process between the other slave clock device and the master clock device may refer to the embodiment of the present invention. description.

202. The master clock device acquires a time when the first time synchronization message is sent through the RF.

The first time synchronization message sent by the master clock device needs to be processed by the physical layer, such as modulation and demodulation, and then transmitted through the RF. Therefore, the physical layer modulation and demodulation process may bring a certain time to the first time synchronization message. The delay and jitter, therefore, the master clock device can realize the processing of the physical layer modulation and demodulation by acquiring the time when the first time synchronization message is sent through the RF. The compensation of the delay increases the accuracy of obtaining the transmission timing of the first time synchronization message.

In an application scenario, the master clock device may obtain the time 1\ sent by the first time synchronization message according to the scheduling information of the first time synchronization message (the scheduling information is usually generated by the medium access control layer). Specifically, the master clock device may obtain, according to the scheduling information of the first time synchronization message, a corresponding time slot sent by the first time synchronization message through the RF, and calculate, according to the local clock and the time slot, send any one of the symbols in the time slot. At the start or end time, as the time when the first time synchronization message is sent by the radio frequency, for example, the end time of transmitting the last symbol in the time slot can be calculated according to the local clock and the time slot, and The time when the first time synchronization message is sent by the radio frequency, or the start time of transmitting the last symbol in the time slot is calculated according to the local clock and the time slot, and is used as the time when the first time synchronization message is sent through the radio frequency or The time at which the first symbol in the time slot is transmitted is calculated according to the local clock and the time slot, and the time when the first time synchronization message is sent as a first time synchronization message is not limited herein.

In another application scenario, the time 1\ sent by the first time synchronization message through the RF may also be obtained by means of hardware (such as a radio device or other hardware device). It should be noted that, when the time synchronization message is obtained by means of hardware recording, the transmitting end and the receiving end can be executed according to a unified hardware recording mechanism, thereby ensuring time synchronization precision of the master-slave time device. For example, in the interaction process of the time synchronization message between the master and slave clock devices, if the master clock device (or the slave clock device) acting as the transmitting end records the time synchronization message through the hardware, the end time of the last symbol in the time slot sent by the RF is recorded. As a time when the time synchronization message is sent by the RF, correspondingly, the slave clock device (or the master clock device) as the receiving end receives the time synchronization by the hardware physical layer of the air interface when receiving the time synchronization message. The start time of the first symbol in the time slot of the message is recorded as the time when the air interface physical layer receives the time synchronization message; if the master clock device (or the slave clock device) serving as the transmitting end passes hardware (such as a radio frequency device) Or other hardware device) sends a time synchronization message via RF The start time of the last symbol in the slot is recorded as the time synchronization cancellation, the packet, the time sent by the RF, and correspondingly, the slave clock device (or master clock device) as the receiving end receives the time synchronization message. At the time, the start time of the second symbol in the time slot of the time synchronization message received by the physical layer of the air interface is recorded by the hardware, and is received as the air interface physical layer. The time of the time synchronization message; if the master clock device (or the slave clock device) as the transmitting end records the time synchronization message through the hardware, the start time of the first symbol in the time slot sent by the RF is recorded as the time When the synchronization message is sent by the RF, the corresponding slave clock device (or master clock device) receives the time synchronization message, and receives the air interface physical layer in the time slot of the time synchronization message through hardware. The start time of the first symbol is recorded as the time when the air interface physical layer receives the time synchronization message, and so on. Specifically, the mechanism for recording the time of sending and receiving the time synchronization message by using the hardware may set the master and slave clock devices before performing the time synchronization operation, which is not limited herein.

203. The master clock device sends a second time synchronization message to the slave clock device, and carries a timestamp of 1\ in the second time synchronization message.

After transmitting the first time synchronization message, the master clock device sends a second time synchronization message carrying a time stamp of 1\ to the slave clock device, such as a follow message Follow_up, so that the slave clock device knows that the master clock device passes When the RF sends the first time synchronization message, the clock device can obtain the time when the air interface physical layer receives the second time synchronization message when receiving the second time synchronization message.

204. The master clock device receives the third time synchronization message sent by the slave clock device, and acquires a time T ₄ when the air interface physical layer receives the third time synchronization message.

In order to improve the correction accuracy, the time synchronization process needs to measure the transmission delay of the time synchronization message between the master and slave clock devices. At this time, the slave clock device sends the third time synchronization message to the master clock device irregularly, such as may be delayed. The request message Delay_Req, the default value of the interval time may be a random value between 4 and 60 seconds. When the third time synchronization message is sent, the slave clock device may acquire the time T sent by the third time synchronization message through the RF. ₃ .

When the primary clock device receives the third time synchronization message, the time Τ ₄ at which the air interface physical layer receives the third time synchronization message is obtained to implement compensation for the processing delay of the physical layer modulation and demodulation.

In an application scenario, when receiving the third time synchronization message, the master clock device may be configured according to scheduling information of the third time synchronization message (the scheduling information may be generated by the master clock device or by the slave clock device, for example, if the master clock device For the macro base station, the slave clock device is a micro base station or a user equipment, etc., the scheduling information may be generated by the master clock device, and vice versa, may be generated by the slave clock device. And obtaining a time T ₄ when the air interface physical layer receives the third time synchronization message. Specifically, the master clock device may obtain, according to the scheduling information of the third time synchronization message, the corresponding time slot of the air interface physical layer to receive the third time synchronization message. And calculating, according to the local clock and the foregoing time slot, a start or end time of the physical layer received by the air interface physical layer as the time τ _{4 of} receiving the third time synchronization message by the air interface physical layer. For example, the start time of the first symbol in the time slot received by the physical layer of the air interface can be calculated according to the local clock and the time slot, and the time τ _{4 of the} third time synchronization message is received as the air interface physical layer. Or, the start time of the second symbol in the time slot received by the physical layer of the air interface is calculated according to the local clock and the time slot, and is received as the time τ _{4 of the} third time synchronization message by the physical layer of the air interface. This is not a limitation.

In an application scenario, when the primary clock device receives the third time synchronization message, the master clock device may also acquire the time when the air interface physical layer receives the third time synchronization message by using hardware recording.

Τ ₄ . For the specific manner of the hardware record, refer to the description in step 202, and details are not described herein again.

205, the master clock time synchronization device sends a fourth message to the slave clock device, and to carry a timestamp Τ ₄ in the fourth time synchronization message.

In an application scenario, after receiving the third time synchronization message, the master clock device may send a fourth time synchronization message carrying the timestamp of τ ₄ to the slave clock device, such as a delayed response message. Resp, so that the slave clock device knows the time T ₄ at which the master clock device receives the third time synchronization message at the air interface physical layer. Alternatively, the master clock is received from the device may be extended clock device sends a message (e.g., packets may follow Fol low_up) after the fourth time from the transmitting apparatus to carry a timestamp clock synchronization message to T _4, as can be delayed In response to the message De lay-Resp, the slave clock device learns the time T ₄ at which the master clock device receives the third time synchronization message at the air interface physical layer.

It should be noted that the foregoing extended message is a message extended from the clock device by extending the 1588v2 protocol, and is sent to the primary clock device after the third time synchronization message is sent, and may carry the slave clock device in the added message. The timestamp of the moment when the RF sends the third time synchronization message, so that the master clock device can know the time. Of course, the slave clock device may also not send the above extended message to the master clock device.

It can be understood that when the fourth time synchronization message is received from the clock device, a time synchronization message interaction process is completed between the master and slave clock devices, and the slave clock device can be based on the clock. The four time information obtained during the synchronization message interaction process is calculated correspondingly, and the local clock can be corrected according to the calculation result, and the slave clock device can also perform the time synchronization message interaction process between the master and slave clock devices. After that, the plurality of calculation results obtained by the calculation are averaged, and the local clock is corrected according to the average value, thereby realizing time synchronization between the master and slave clock devices.

It can be understood that the foregoing time synchronization method described in this embodiment can be applied to various communication systems, such as a Long Term Evolution (LTE) communication system, a Universal Mobile Telecommunications System (UMTS), and a broadband. WCDMA (Wideband Code Division Multiple Access), Worldwide Interoperability for Microwave Access (WIMAX), Global System for Mobile (GSM), etc. The master clock device and the slave clock device may be base stations or other devices having wireless links.

It can be seen that, in the embodiment, the master clock device obtains the time when the first time synchronization message is sent by the RF and the time when the air interface physical layer receives the third time synchronization message, and passes the timestamps of the two times respectively through the second time. The synchronization message and the fourth time synchronization message are sent to the slave clock device, so that the slave clock device can know that the master clock device sends the first time synchronization message through the RF and the third time synchronization message is received at the air interface physical layer, which is correspondingly improved. The clock device subsequently calculates the accuracy of the clock offset from the master clock device, and uses a more accurate calculation result to correct the local clock of the slave clock device, thereby improving the time synchronization accuracy of the master-slave clock device.

The time synchronization method in the embodiment of the present invention will be described below from the perspective of a clock device.

Another embodiment of the time synchronization method in the embodiment of the present invention includes: receiving a first time synchronization message sent by the master clock device from the clock device, and acquiring a time T ₂ at which the air interface physical layer receives the first time synchronization message; a second time synchronization message sent by the master clock device, and acquiring a timestamp of the time 1\ carried in the second time synchronization message, where the time 1@ the primary clock device sends the first time synchronization message through the RF Sending a third time synchronization message to the master clock device, and acquiring the time Τ ₃ sent by the third time synchronization message through the RF; The clock device receives the fourth time synchronization message sent by the master clock device, and acquires a timestamp of the time τ ₄ carried in the fourth time synchronization message, where the τ ₄ is received by the master clock device on the physical layer of the air interface. The time of the third time synchronization message; the clock offset from the master clock device is calculated according to the above τ ₂ , τ ₃ and τ ₄ ; and the local clock is corrected according to the result of the calculation.

Please refer to Figure 3, the specific steps may include:

301: Receive a first time synchronization message sent by the master clock device from the clock device, and obtain a time Τ ₂ when the air interface physical layer receives the first time synchronization message;

When the first time synchronization message is received from the clock device, the time T ₂ at which the air interface physical layer receives the first time synchronization message is obtained, so as to implement compensation for the processing delay of the physical layer modulation and demodulation.

In an application scenario, when receiving the first time synchronization message from the clock device, the scheduling information of the first time synchronization message may be generated according to the scheduling information of the first time synchronization device (the scheduling information may be generated by the master clock device, or may be generated by the slave clock device, for example, if the master clock device is a macro base station, from the clock device is a micro base station or a user equipment, the scheduling information by the master clock device generates, on the contrary, by the slave clock device generates), obtaining air interface physical layer receiving the first time synchronization message time Τ ₂ Specifically, the slave clock device may obtain, according to the scheduling information of the first time synchronization message, a corresponding time slot in which the air interface physical layer receives the first time synchronization message, and calculate, according to the local clock and the time slot, the physical layer of the air interface receives the foregoing time. The start or end time of any one of the slots is received as the time Τ _{2 of} the first time synchronization message as the air interface physical layer. For example, the physical layer reception of the air interface can be calculated according to the local clock and the time slot. To the beginning of the first symbol in the above time slot, as the physical layer of the air interface The time of receiving the first time synchronization message Τ _2, or calculate the starting time of the air interface physical layer receives the slot of the second symbol and said slots according to the local clock, which is received as a physical layer air interface The time Τ _{2 of the} first time synchronization message is not limited herein. In another application scenario, when the apparatus is received from the clock synchronization message to said first time, may acquire the physical layer air interface receiving the first time synchronization message by time T ₂ records the hardware embodiment. It should be noted that, when the time synchronization message is sent by the hardware (such as a radio frequency device or other hardware device), the transmitting end and the receiving end can be executed according to a unified hardware recording mechanism. Assuring the time synchronization accuracy of the master-slave time device, for example, when the master-slave clock device performs the time synchronization message interaction, if the master clock device (or the slave clock device) acting as the sender transmits the time synchronization message through the RF through the hardware The end time of the last symbol in the slot is recorded as the time when the time synchronization message is sent by the RF, and accordingly, the slave clock device (or the master clock device) as the receiving end passes the time synchronization message when receiving the time synchronization message. The hardware records the start time of the first symbol in the time slot in which the air interface physical layer receives the time synchronization message, and records the time when the air interface physical layer receives the time synchronization message; if it is the master clock device of the transmitting end ( Or from the clock device) through the hardware to send time synchronization messages through the RF The start time of the last symbol in the outgoing time slot is recorded as the time when the time synchronization message is sent by the RF, and accordingly, the slave clock device (or master clock device) as the receiving end receives the In the time synchronization message, the start time of the second symbol in the time slot in which the air interface physical layer receives the time synchronization message is recorded by the hardware, and is recorded as the time when the air interface physical layer receives the time synchronization message; The master clock device (or the slave clock device) as the transmitting end records the time synchronization message through the hardware at the start time of the first symbol in the time slot sent by the RF as the time when the time synchronization message is sent through the RF, correspondingly The slave clock device (or the master clock device), as the receiving end, records the start time of the first symbol in the time slot of the time slot physical layer receiving the time synchronization message by hardware when receiving the time synchronization message. As the time when the air interface physical layer receives the time synchronization, and so on. Specifically, the mechanism for recording the time of the transmission and the reception of the time synchronization by the hardware may set the master-slave clock device before the time synchronization operation is performed, which is not limited herein.

The receiving, by the clock device, the second time synchronization message sent by the master clock device, and acquiring the timestamp of the time 1 carried in the second time synchronization message;

The slave device receives the second time synchronization message sent by the master clock device, such as the following message Follow_up, and obtains the time stamp of 1\ carried in the second time synchronization message, so that Perform subsequent calculations. Where 1\ is the time when the above-mentioned master clock device sends the first time synchronization message through the RF.

303. The slave clock device sends a third time synchronization message to the master clock device.

304, the third slave clock device acquiring the time synchronization message sent by the RF time T _3;

In order to improve the accuracy of the correction, the time synchronization process needs to measure the transmission delay of the time synchronization message between the master and the slave device. At this time, the slave clock device sends the third time synchronization message to the master clock device irregularly, such as delay. The request message Delay_Req has an interval value default value of a random value between 4 and 60 seconds.

Since the third time synchronization message sent from the clock device needs to be processed by the physical layer, such as modulation and demodulation, and then transmitted through the RF, the modulation and demodulation processing of the physical layer may bring a certain time to the transmission of the third time synchronization message. Delay and jitter. Therefore, the time delay of processing the physical layer modulation and demodulation can be compensated by the clock device by acquiring the time when the third time synchronization message is sent through the RF, thereby improving the transmission time of acquiring the third time synchronization message. The accuracy.

In an application scenario, the slave clock device may perform scheduling information according to the third time synchronization message (the scheduling information may be generated by the master clock device or may be generated by the slave clock device, for example, if the master clock device is a macro base station, the slave clock device is a micro base station or a user equipment, the scheduling information generated by the master clock device, and vice versa, may be generated from the clock device), the third time acquisition time synchronization message sent by RF T _3, in particular, from the clock apparatus according to And scheduling information of the third time synchronization message, acquiring a corresponding time slot sent by the third time synchronization message through the RF, calculating, according to the local clock and the time slot, a start or end time of sending any one of the time slots, and As the time Τ ₃ sent by the third time synchronization message through the RF, for example, the end time of transmitting the last symbol in the time slot may be calculated according to the local clock and the time slot, and used as the third time synchronization message. by the time the RF emission Τ _3, or calculated according to the local clock and said transmission time slot the Starting time of the last symbol of the slot, by the time the RF emission as a third time synchronization message Τ _3, or from the local clock and the calculated according to the above-described first symbol transmission time slot the slot At the beginning time, it is used as the time Τ ₃ sent by the third time synchronization message through the RF, which is not limited herein.

In another application scenario, the time Τ ₃ sent by the third time synchronization message through the RF may also be obtained by means of hardware recording. Refer to step 301 for the specific manner of hardware recording. The description in the description will not be repeated here.

It should be noted that, in an application scenario, the slave clock device may send a new message to the master clock device, such as a follow-up report, by extending the 1588 ν2 protocol after acquiring the third time synchronization message through the time T ₃ sent by the RF. Wen Fol low_up, and carry timestamp T ₃ in the new message to the master device can know the above-described clock time synchronization message sent from the third apparatus through the RF clock time Τ _3. Of course, the slave clock device may not send the above-mentioned new message to the master clock device, which is not limited herein.

305. Receive, by the clock device, a fourth time synchronization message sent by the primary clock device, and obtain a timestamp of the time Τ ₄ carried in the fourth time synchronization message.

A fourth clock device by receiving the time synchronization message transmitted by the master clock device, for example, may be a Delay_Resp delay response packet, acquires a time stamp of the synchronization message carried in a fourth time T ₄ of the, for the subsequent calculations. Where Τ ₄ is the time when the master clock device receives the third time synchronization message at the air interface physical layer.

306. The slave clock device calculates a clock offset from the master clock device according to the obtained Τ ₂ , Τ _3, and Τ ₄ ;

After obtaining the above Τ ₂ , Τ ₃ and Τ ₄ from the clock device, the message average delay Delay between the master clock device and the master clock device can be calculated according to the following formula, and the clock offset from the master clock device can be calculated accordingly. Offset:

T ₂ = T! + Delay + Offset; T ₄ = T ₃ + Delay-Offset.

The above two formulas can become:

Delay = ( T ₂ - 1\+1> T ₃ ) 12;

Offset= T ₂ - TV Delay, ie Offset= ( T ₂ - TT ₄ + T ₃ ) /2.

It should be noted that, after the clock device can pass the time synchronization message interaction process between the master and slave clock devices, the values of the multiple Off sets obtained by the calculation are averaged.

307. The slave clock device corrects its local clock according to the calculated result;

According to the result of the calculation in step 306, the slave clock device may correct the local clock according to the clock offset Off set, or may perform the clock skew according to the calculation after the time synchronization message interaction process between the master and slave clock devices. The average of the shift Off set is corrected for its local clock to achieve time synchronization with the master clock device. It should be noted that the time synchronization method described in this embodiment can be applied to various communication systems, such as UMTS, WCDMA, WIMAX, GSM, and LTE communication systems. The master clock device and the slave clock device can be base stations or other devices with wireless links.

It can be seen that, in this embodiment, the time when the first time synchronization message is received by the clock device by acquiring the physical layer of the air interface, and the time when the third time synchronization message is sent by the RF, and the second time synchronization message is received. The time of the first time synchronization message sent by the master clock device carried in the two time synchronization messages and the time when the master clock device receives the third time synchronization message at the physical layer of the air interface is obtained. The stamping device can make the slave clock device more accurately calculate the clock offset from the master clock device according to the obtained four time information, and correspondingly improve the accuracy of the slave clock device to correct the local clock according to the calculation result. , thereby improving the time synchronization accuracy of the master-slave clock device. In order to facilitate a better understanding of the technical solution of the present invention, the following is an example of the time when the master-slave clock device obtains the time for transmitting or receiving the time synchronization message through the scheduling information or the time-frequency resource information, as shown in FIG. 4-a. Another embodiment of the time synchronization method in the embodiment of the present invention may specifically include:

401. The master clock device sends a time synchronization message Sync to the slave clock device.

When time synchronization is required, the default primary clock device periodically sends a unique Sync packet in multicast according to the preset interval (default is 2 seconds), and all are in the default primary clock device network. Within the segment, and the same slave clock device as the master clock device can receive the Sync message.

402. The master clock device obtains the time when the Sync message is sent through the RF according to the scheduling information of the Sync message.

In an application scenario, the master clock device can obtain the corresponding time slot sent by the Sync message through the RF according to the scheduling information of the Sync message, and calculate the last symbol in the time slot according to the local clock and the time slot. At the end time, it is used as the Sync message at the time 1\ sent by the RF, or the start time of the last symbol in the time slot is calculated according to the local clock and the above time slot, and is used as the Sync message through the RF. The time of time 1\ is sent, or, according to the local clock and the above time slot, the starting time of transmitting the first symbol in the time slot is calculated, and The time T\ sent by the Sync message through the RF, or the start or end time of sending other symbols in the time slot according to the local clock and the above time slot, and sent as a Sync message through the RF. Time 1\ , not limited here.

The above time slot may be a time slot corresponding to one radio frame or subframe.

403. Receive a Sync message from the clock device, and obtain a time T ₂ when the Sync message receives the Sync message at the physical layer of the air interface according to the scheduling information of the Sync message.

In an application scenario, the slave clock device obtains the time slot of the physical layer receiving the Sync according to the scheduling information of the Sync message, and calculates the first one of the time slots received by the physical layer of the air interface according to the local clock and the time slot. The start time of the symbol is received as the time T _{2 of the} Sync message as the air interface physical layer, or the start of the second symbol in the time slot received by the physical layer of the air interface is calculated according to the local clock and the time slot. At the moment, it is received as the time T _{2 of the} Sync message as the air interface physical layer, or the start or end time of the other symbols in the time slot received by the physical layer of the air interface may be calculated according to the local clock and the time slot. The time T _{2 at} which the Sync message is received as the air interface physical layer is not limited herein. The time slot may be a time slot corresponding to one radio frame or a subframe.

404. The master clock device passes the timestamp of T\ to the slave clock device by following the message Fo 11 ow-up;

After transmitting the Sync message, the master clock device sends a Fol low_up message carrying the time stamp of 1\ to the slave clock device, so that the slave clock device knows the time 1\ at which the master clock device sends the Sync message through the RF.

405. Send a delay request message from the clock device to the master clock device. De lay-Req;

In order to improve the correction accuracy, the time synchronization process needs to measure the transmission delay of the time synchronization message between the master and the slave device. At this time, the slave clock device sends the De l ay-Req^ message to the master clock device irregularly. The interval defaults to a random value between 4 and 60 seconds.

406, according to scheduling information from the clock apparatus De lay-Req message, acquire the time De lay-Req message sent by RF T _3;

In an application scenario, the slave clock device obtains, according to the scheduling information of the Delay-Req packet, the time slot sent by the Delay-Red 4 message through the RF, and calculates and sends the time slot according to the local clock and the time slot. The end of the last symbol, use it as De lay-Red The time τ _{3 is} sent, or the start time of transmitting the last symbol in the time slot is calculated according to the local clock and the time slot, and is used as the time T ₃ sent by the Delay-Req message through the RF, or Calculating, according to the local clock and the foregoing time slot, the starting time of transmitting the first symbol in the time slot, and using it as the time when the Delay-Req message is sent by the RF Τ ₃ , or according to the local clock and the foregoing The time slot is used to calculate the start or end time of the other symbols in the time slot, and is used as the time T ₃ sent by the Delay-Req message through the RF, which is not limited herein.

407. The master clock device receives the Delay-Req packet sent by the slave clock device, and obtains a time T ₄ when the air interface physical layer receives the De lay-Req^ message according to the scheduling information of the Delay-Red message. ;

In an application scenario, the master clock device obtains the time slot of the Delay-Req packet received by the physical layer of the air interface according to the scheduling information of the Delay-Req packet, and calculates the physical layer of the air interface according to the local clock and the time slot. The start time of the first symbol in the time slot is received as the air interface physical layer at time T _{4 of the} Delay-Req message, or the physical layer of the air interface is received according to the local clock and the time slot. The start time of the second symbol in the time slot is received as the air interface physical layer at time T _{4 of the} Delay-Red frame, or the physical layer reception of the air interface may be calculated according to the local clock and the time slot. The time T _{4 of the} Delay-Req message is received as the air interface physical layer at the start or end time of the other symbols in the time slot, which is not limited herein.

408. The slave clock device passes the timestamp of 1^ to the master clock device by following the message Fol low_up;

Slave clock device after transmitting the message De lay-Red, by extending-1588v2, to the new master clock device sends timestamp carrying Fol low_u T _P of packet _3, so that the master clock device can be known from the above-described clock The device sends the time T _{3 of the} above Delay-Red message through the RF.

409, by delaying the response to the master clock device De lay-Resp message to the time stamp T is transmitted to the slave clock device _4;

After receiving the Fol low_up message sent by the slave clock device, the master clock device sends a De 1 ay-Re s ρ message carrying the time stamp of T ₄ to the slave clock device, so that the slave clock device learns the master clock device. The time T _{4 of the} above Delay-Red message is received at the air interface physical layer.

410. The slave clock device calculates a clock offset from the master clock device according to the obtained Τ\ , Τ ₂ , ^ , and Τ ₄ ; After acquiring the τ ₂ , τ ₃ and τ ₄ from the clock device, the average delay of the message between the master clock device and the master clock device can be calculated according to the following formula, and the clock offset from the master clock device can be calculated accordingly. Offset:

T ₂ = T! + Delay + Offset; T ₄ = T ₃ + Delay-Offset.

The above two formulas can become:

Delay = ( T ₂ - 1\+1> T ₃ ) 12;

0ff set= T ₂ - Τ - De lay, ie Off set= ( T ₂ _ T -T ₄ + T ₃ ) /2.

It should be noted that, after the clock device can pass the time synchronization message interaction process between the master and slave clock devices, the multiple Of f sets obtained by calculation are averaged.

411. The slave clock device corrects its local clock according to the calculated result;

According to the result of the calculation in step 410, the slave clock device can correct the local clock according to the clock offset Off set, or after calculating the time synchronization message interaction process between the master and slave clock devices. The average of the offset Off set is corrected for its local clock to achieve time synchronization with the master clock device.

For example, a sub-frame defined in the LTE system includes two time slots, each of which is 0. 5, for example, in the LTE system, by using the scheduling information to obtain the time of sending or receiving the time synchronization message. The time slot of milliseconds includes 6 or 7 Orthogonal Frequency Division Multiplexing (OFDM) symbols, as shown in Figure 4b, and Figure 4-b shows the LTE system. A time-frequency structure of a 0.5 millisecond time slot.

The data to be transmitted after the baseband processing is carried by the 0F picture symbol, at the beginning of each symbol (such as ^, t ₂ , t ₃ , t ₄ , t ₅ , t ₆ and t _{7 in} Figure 4_b ) Transmitted by RF, correspondingly, the receiving end correspondingly receives the above-mentioned 0F drawing symbol.

In order to ensure the time synchronization accuracy of the master-slave clock device, the present invention provides three optional ways to obtain the time synchronization message transmission or reception time through the scheduling information, and the three methods provided may be better. The symmetry of the time that the guaranteed time synchronization message is transmitted back and forth between the master and slave clock devices ensures the time synchronization accuracy of the master-slave time device.

A manner of obtaining a time for transmitting or receiving a time synchronization message by using scheduling information is provided in the embodiment of the present invention. For example, as shown in Figure 4-c, the specific implementation manner is as follows:

As the clock device of the sender (such as the master clock device or the slave clock device), the transmission time is the same. When a step message (such as a Sync message or a De 1 ay.Req message), the time slot of the subframe that carries the time synchronization message sent by the RF may be obtained according to the scheduling information of the time synchronization message, according to the local clock and the foregoing The time slot calculates the end time ^ and ^ of the last symbol in the time slot, and uses ^ and as the time when the time synchronization message is sent through the RF, correspondingly as the clock device of the receiving end (such as the slave clock device or the master clock) The device, when receiving the time synchronization message, obtains a time slot of the subframe in which the air interface physical layer receives the time synchronization message according to the scheduling information of the time synchronization message, and calculates the physical layer of the air interface according to the local clock and the time slot. Receiving the start time ^ and t _dl of the first symbol in the time slot, and taking ^ and t _dl as the time when the air interface physical layer receives the time synchronization message, as can be seen from Figure 4-c, the time synchronization message is The delays delay and de lay' in the transmission line are symmetrical, and because the acquisition is the end time of the last symbol in the time slot of the time synchronization message sent by RF and the physical interface of the air interface Receiving the start time of the first symbol in the time slot of the time synchronization message, so that the time of the transmission or reception of the subframe by the master-slave clock device due to the unsynchronization of the frequency between the master and slave clock devices can be eliminated, so With this acquisition method, the sending time and receiving time of the time synchronization message can be obtained more accurately.

Another manner for obtaining a time for transmitting or receiving a time synchronization message by using scheduling information is also provided in the embodiment of the present invention. For details, refer to FIG. 4-d. The specific manner is as follows:

As a clock device of the transmitting end (such as a master clock device or a slave clock device), when sending a time synchronization message (such as a Sync message or a De 1 ay.Req message), the scheduling information of the time synchronization message may be obtained through the RF. The transmitted time slot of the subframe carrying the time synchronization message calculates the starting times t _a2 and t of the last symbol in the time slot according to the local clock and the time slot. ₂ , will t _a2 and t. _2, as the time when the time synchronization message is sent by the RF, correspondingly, the clock device as the receiving end (such as the slave clock device or the master clock device), when receiving the time synchronization message, obtains according to the scheduling information of the time synchronization message. The air interface physical layer receives the time slot of the subframe that carries the time synchronization message, and calculates, according to the local clock and the time slot, the start times t _b2 and t _d2 of the second symbol in the time slot received by the air interface physical layer, t _b2 and t _d2 are the moments when the air interface physical layer receives the time synchronization message. As can be seen from Figure 4-d, the delays of the time synchronization message during transmission are desymmetrical and de lay', and t _a2 and t _d2 Symmetric, t _b2 and t. ₂ symmetry, the acquisition time and the receiving time of the time synchronization message can also be accurately recorded by this acquisition method.

Another embodiment of the present invention further provides that the sending or receiving time is the same through scheduling information. The way to step the message, please refer to Figure 4-e in the following way:

As a clock device of the transmitting end (such as a master clock device or a slave clock device), when sending a time synchronization message (such as a Sync message or a De 1 ay.Req message), the scheduling information of the time synchronization message may be obtained through the RF. The transmitted time slot of the subframe carrying the time synchronization message calculates the starting times t _a3 and t of the first symbol in the time slot according to the local clock and the time slot. ₃ , will t _a3 and t. ₃ as the time when the time synchronization message is sent by the RF, and correspondingly, the clock device as the receiving end (such as the slave clock device or the master clock device), when receiving the time synchronization message, obtains according to the scheduling information of the time synchronization message. The air interface physical layer receives the time slot of the subframe that carries the time synchronization message, and calculates, according to the local clock and the time slot, the start times t _b3 and t _d3 of the first symbol in the time slot received by the air interface physical layer, t _b3 and t _d3 are the moments when the air interface physical layer receives the time synchronization message. As can be seen from Figure 4-e, the delays of the time synchronization message during transmission are desymmetrical and de yy', so In the same way, the sending time and the receiving time of the time synchronization message can be obtained more accurately.

It can be seen that, in this embodiment, the time when the time synchronization message is obtained by the scheduling information and the time when the air interface physical layer receives the time synchronization message, the compensation for the processing delay of the physical layer modulation and demodulation is realized, thereby eliminating The effect of obtaining the accuracy of the transmission and reception time of the time synchronization message due to the delay and jitter of the processing such as the physical layer modulation and demodulation, and improving the accuracy of the time of transmitting and receiving the time synchronization message, The obtained transmission and reception time information of the higher-precision time synchronization message is time-synchronized by the master-slave clock device, and the time synchronization accuracy of the master-slave clock device can be improved accordingly. In order to facilitate a better understanding of the technical solution of the present invention, the time synchronization method described in the embodiment of the present invention is described in detail by taking the time when the master-slave clock device acquires the time synchronization message at the physical layer of the air interface by means of hardware recording. description.

Referring to FIG. 5-a, another embodiment of the time synchronization method in the embodiment of the present invention may specifically include:

501, the master clock device sends a time synchronization message Sync to the slave clock device;

When time synchronization is required, the default primary clock device periodically sends a unique Sync packet in multicast according to the preset interval (default is 2 seconds), and all are in the default primary clock device network. Within the segment, and the same slave clock device as the master clock device Received a Sync message.

502. The master clock device records the time when the Sync message is sent through the RF through the hardware 1\;

When the master clock device sends a Sync message, the Sync message can be recorded by the hardware (such as a radio device or other hardware device) through the end time of the last symbol in the time slot sent by the RF, and sent as a Sync message through the RF. At the moment, or by hardware, the Sync message is recorded by the start time of the last symbol in the time slot sent by the RF, and is recorded as the Sync message by the start time of the symbol, as Sync. The time when the text is sent by the RF, or the Sync/艮 text can be recorded by the hardware through the start or end time of other symbols in the time slot sent by the RF, as the time when the Sync message is sent through the RF. There is no limit. The time slot may be a time slot corresponding to one radio frame or subframe.

503, receives the Sync device from the clock ₁₂ at time packet, the physical layer air interface and receives the Sync message recording time T ₂ by hardware;

When receiving the Sync message from the clock device, the clock device may record the start time of the first symbol in the time slot of the Sync message received by the physical layer of the air interface, as the time when the physical layer of the air interface receives the Sync message. Alternatively, the start time of the second symbol in the slot of the Sync packet received by the physical layer of the air interface is recorded by the hardware, as the time when the physical layer of the air interface receives the Sync message, or the physical layer of the air interface may be used by hardware. The start or end time of the other symbol in the slot in which the Sync packet is received is recorded as the time at which the Sync packet is received by the physical layer of the air interface, which is not limited herein.

504. The master clock device passes the timestamp of T\ to the slave clock device by following the message Fo 1 1 ow-up;

After transmitting the Sync message, the master clock device sends a Fo l low_up message carrying the time stamp of 1\ to the slave clock device, so that the slave clock device knows the time 1 when the master clock device sends the Sync message through the RF. .

505. The slave clock device sends a delay request message De 1 ay - Re d to the master clock device at time 1 ₃ ; in order to improve the correction precision, the time synchronization process needs to measure the transmission delay of the time synchronization message between the master and the slave device. At this time, the slave clock device sends the De l ay-Req^ message to the master clock device irregularly. The interval time defaults to a random value between 4 and 60 seconds.

506. The slave device records the time T ₃ sent by the Delay-Red message through the hardware through the hardware. When the Delay-Req message is sent from the clock device, the De l ay-Req message can be sent through the hardware. The end time of the last symbol in the time slot sent by the RF is recorded as the time when the Delay-Req message is sent by RF, or by the hardware to send the Delay-Red message to the time slot sent by the RF. The start time of the last symbol is recorded as the time when the release is made by the Delay-Req ·^艮 text, or the first of the time slots issued by the RF by Delay-Req ^t艮 by the hardware. The start time of the symbol is recorded as the time when the Delay-Rec^ message is sent by the RF, or the start of other symbols in the time slot issued by the RF by Delay-Red can also be transmitted by hardware. Recorded at the end time or as the time when the Delay-Req message is sent by RF, it is not limited here.

507, received by the master clock device De lay-Req message transmitted from the clock device at the time t _4, and through the air interface physical layer hardware record received De l ay-Req ^ Gen packet time T _4;

When receiving the Delay-Req message, the master clock device can record the start time of the first symbol in the time slot of the physical layer receiving the Delay-Req^ message through the hardware, and receive it as the air interface physical layer. At the time of the Delay-Req message, or by the hardware, the start time of the second symbol in the time slot of the physical layer receiving the De 1 ay-Req 艮 text is recorded by the hardware, and the De is received as the physical layer of the air interface. The time of the lay-red packet, or the hardware starts to record the start or end time of other symbols in the time slot of the Delay-Red 物理 physical layer, and receive the De lay-Req as the air interface physical layer. The time of the message is not limited here.

508. The slave clock device passes the timestamp of 1^ to the master clock device by following the message Fol low_up;

509, by delaying the response to the master clock device De lay-Resp message to the time stamp T is transmitted to the slave clock device _4;

510. The slave clock device calculates a clock offset from the master clock device according to the foregoing Τ\, Τ ₂ , ^, and Τ ₄ ;

After the clock device obtains the above Τ ₂ , Τ ₃ and Τ ₄ , the average delay of the message between the slave clock and the master clock device can be calculated according to the following formula, and the master clock is calculated accordingly. Backup clock offset Offset:

T ₂ = T! + Delay + Offset; T ₄ = T ₃ + Delay-Offset.

The above two formulas can become:

Delay = ( T ₂ - 1\+1> T ₃ ) 12;

0ff set= T ₂ - Τ - De lay, ie Off set= ( T ₂ _ T -T ₄ + T ₃ ) /2.

511. The slave clock device corrects its local clock according to the calculated result.

According to the result of the calculation in step 510, the slave clock device can correct its local clock according to the clock offset Off set, thereby achieving time synchronization with the master clock device.

It can be understood that the steps of implementing the time synchronization method of the present invention by other hardware recording mechanisms may refer to the time synchronization method described in the foregoing embodiments, and the specific hardware recording mechanism may set the master-slave clock device when performing the time synchronization operation. This will not be repeated here.

The LTE system has a 0. 5ms time slot in the LTE system. The following is a description of the hardware recording mechanism in the hardware recording mode, where the LTE system uses a hardware recording method to obtain a time of sending or receiving a time synchronization message. A time-frequency structure can be as shown in the time-frequency structure shown in Figure 4-b.

In order to ensure the time synchronization accuracy of the master-slave time device, three optional hardware recording mechanisms are provided in the embodiment of the present invention. By providing the three preferred hardware recording mechanisms, the time synchronization message can be better guaranteed in the master-slave The symmetry of the time of transmission between clock devices, thus ensuring the time synchronization accuracy of the master-slave time device.

A hardware recording mechanism provided by the present invention can be referred to as FIG. 5-b, and the specific implementation manner is as follows: As a clock device of the transmitting end (such as a master clock device or a slave clock device), a time synchronization message (such as a Sync message or When De 1 ay.Req message), the time synchronization message is transmitted by hardware through the end times t _a4 and t of the last symbol in the time slot issued by the RF. _{4 is} recorded as the time when the time synchronization message is sent by the RF, and correspondingly, the clock device (such as the slave clock device or the master clock device) as the receiving end receives the time synchronization message through the hardware, and receives the physical layer of the air interface through the hardware. The start times t _b4 and t _d4 of the first symbol in the time slot of the time synchronization message are recorded as the time when the air interface physical layer receives the time synchronization message. As can be seen from FIG. 5-b, the time synchronization message is The delays delay and de lay' in the transmission line are symmetrical, and because of the hardware Recording is the end time of the last symbol in the time slot of the time synchronization message sent by the RF and the start time of the first symbol in the time slot of the time slot receiving the time synchronization message of the air interface physical layer, so the master slave clock device is eliminated. The time when the master-slave clock device transmits or receives the subframe is not synchronized due to the unsynchronized frequency, and therefore, the hardware recording method can more accurately record the transmission timing and the reception timing of the time synchronization message.

Another hardware recording mechanism provided by the present invention can be referred to FIG. 5-c in the following manner: As a clock device of the transmitting end (such as a master clock device or a slave clock device), a time synchronization message (such as a Sync message or a De lay) is sent. -Req message), the time synchronization message is passed by hardware through the start time ^ ₅ and t of the last symbol in the time slot issued by the RF. ₅ recorded as the time of the time synchronization message through the RF emission, corresponding, as a clock device receiving end (e.g., the slave clock device, or master clock device), upon receiving the time synchronization message, by a hardware empty physical layer receiving opening The start times t _b5 and t _d5 of the second symbol in the time slot of the time synchronization message are recorded as the time at which the air interface physical layer receives the time synchronization message. As can be seen from FIG. 5-c, the time synchronization message is The delays delay and de lay' during transmission are symmetrical, and ^ ₅ and t _{d5 are} symmetric, t _b5 and t. ₅ symmetry, the hardware recording method can also accurately record the sending time and receiving time of the time synchronization message.

Another hardware recording mechanism provided by the present invention can be referred to FIG. 5-d in the following manner: As a clock device of the transmitting end (such as a master clock device or a slave clock device), a time synchronization message (such as a Sync message or De 1) is sent. When ay.Req message), the time synchronization message is transmitted by hardware through the start times t _a6 and t of the first symbol in the time slot issued by the RF. ₆ recorded as the time of the time synchronization message through the RF emission, corresponding, as a clock device receiving end (e.g., the slave clock device, or master clock device), upon receiving the time synchronization message, by a hardware empty physical layer receiving opening The time instants t _b6 and t _d6 of the first symbol in the time slot of the time synchronization message are recorded as the time at which the air interface physical layer receives the time synchronization message. As can be seen from FIG. 5-d, the time synchronization message is The delays delay and de lay' in the transmission process are symmetrical, and the hardware recording method can also accurately record the sending time and receiving time of the time synchronization message.

It can be seen that, in this embodiment, the time when the master-slave clock device transmits and receives the time synchronization message at the physical layer of the air interface is obtained by means of hardware recording, and the delay and jitter caused by the processing and demodulation of the physical layer are eliminated. Obtain the accuracy of the transmission and reception time of the time synchronization message The accuracy of obtaining the time of sending and receiving time synchronization messages is improved, and the time synchronization of the master and slave clock devices is performed by using the acquired higher precision time synchronization message transmission and reception time information, thereby improving the master-slave correspondingly Time synchronization accuracy of the clock device. The master clock device according to the foregoing method of the embodiment of the present invention is described below. As shown in FIG. 6, a master clock device according to an embodiment of the present invention includes:

The transceiver module 601 is configured to send a first time synchronization message to the slave clock device, and obtain a time when the first time synchronization message is sent by using the RF

The obtaining module 602 is configured to acquire a time when the transceiver module 601 sends the first time synchronization message by using the radio frequency.

In an application scenario, the obtaining module 602 is specifically configured to obtain, according to the scheduling information of the first time synchronization message, a time when the first time synchronization message is sent by using the RF or a time when the first time synchronization message is sent by the hardware through the RF. \.

In an actual application, the obtaining module 602 can include:

The obtaining module 1 is configured to obtain, according to the scheduling information of the first time synchronization message, a corresponding time slot sent by the first time synchronization message by using a radio frequency;

with,

The processing module 1 is configured to calculate, according to the time slot acquired by the local clock and the acquiring module, the end time of sending the last symbol in the time slot, as the time when the first time synchronization message is sent by using the radio frequency, or according to the local time. The time slot obtained by the clock and the acquiring module calculates the starting time of transmitting the last symbol in the time slot, and uses it as the time when the first time synchronization message is sent by using the radio frequency or acquired according to the local clock and the acquiring module 1. The time slot calculates the start time of transmitting the first symbol in the above time slot, and uses it as the time 1\ that the first time synchronization message is sent through the radio frequency.

The transceiver module 601 is further configured to send a second time synchronization message to the slave clock device, and carry a timestamp of the T i in the second time synchronization message;

The transceiver module 601 is further configured to receive the third time synchronization message sent by the slave clock device, and the acquiring module 602 is further configured to acquire, according to the third time synchronization message received by the transceiver module 601, the air interface physical layer to receive the third time synchronization message. Time T ₄ ;

In an application scenario, the obtaining module 602 is specifically configured to synchronize according to the foregoing third time. Scheduling information message, acquires the air interface physical layer receives the third time synchronization message a time τ _4; or a hardware recording time τ ₄ by the air interface physical layer receives the third time synchronization messages.

In an actual application, the obtaining module 602 includes:

The obtaining module 2 is configured to obtain, according to the scheduling information of the third time synchronization message, a corresponding time slot in which the air interface physical layer receives the third time synchronization message;

with,

The processing module 2 is configured to calculate, according to the time slot acquired by the local clock and the acquiring module 2, the start time of the first symbol in the time slot received by the physical layer of the air interface, and receive the same as the primary clock device in the physical layer of the air interface. The time Τ ₄ to the third time synchronization message, or the calculation of the start time of the second symbol in the time slot received by the physical layer of the air interface according to the local clock and the acquisition module 2, as the master clock The device receives the time τ _{4 of} the third time synchronization message at the air interface physical layer.

Transceiver module 601 is further configured to the clock synchronization message from a sending device a fourth time, and carry timestamp Î¤ ₄ in the fourth time synchronization message; to calculate according to the clock apparatus Ί ₁ and ₄ from the slave clock Î¤ The clock offset of the device from the master clock device, and correcting the local clock of the slave clock device according to the calculated clock offset.

Further, in an application scenario, the transceiver module 601 is further configured to receive the new message sent by the slave clock device by using the extended 1588 ν2 protocol, such as the following message F1 1 ow.up, and the obtaining module 602 may also be used to obtain The timestamp of Τ ₃ carried in the above new message.

In an application scenario, the first time synchronization message is, for example, a time synchronization message Sync or other message; the second time synchronization message is, for example, a follow-up message Fo 1 1 ow_ up or other message; the third time synchronization message is, for example, Deferred request message De lay-Req or other message; The fourth time synchronization message is, for example, a delayed response message De lay-Re sp or other message.

It should be noted that the master clock device in this embodiment may be used as the master clock device in the foregoing method embodiment, and may be used to implement all the technical solutions in the foregoing method embodiments, and the functions of the respective function modules may be according to the foregoing method embodiments. For a specific implementation of the method, reference may be made to the related description in the foregoing embodiments, and details are not described herein again.

It can be seen that, in this embodiment, the master clock device obtains, by the obtaining module 602, the time when the first time synchronization message is sent by the RF and the time when the air interface physical layer receives the third time synchronization message. And sending, by the transceiver module 601, the timestamps of the two moments to the slave clock device through the second time synchronization message and the fourth time synchronization message, respectively, so that the slave clock device can know that the master clock device sends the first time through the RF. Synchronization message and the moment when the third time synchronization message is received at the physical layer of the air interface, correspondingly improve the accuracy of the clock device to calculate the clock offset from the master clock device, and use the more accurate calculation result to the slave clock device. The local clock is corrected to improve the time synchronization accuracy of the master and slave clock devices.

As shown in the embodiment of the present invention, a slave clock device includes:

The transceiver module 701 is configured to receive the first time synchronization message sent by the master clock device, and the acquiring module 702 is configured to obtain, according to the first time synchronization message received by the transceiver module 701, the air interface physical layer to receive the first time synchronization message. Time T ₂ ;

In an application scenario, the obtaining module 702 is specifically configured to obtain, according to the scheduling information of the first time synchronization message, a time Τ ₂ when the physical interface of the air interface receives the first time synchronization message; or receive the first physical layer through the hardware recording interface. The time of the synchronization message at a time Τ ₂ .

In an actual application, the obtaining module 702 can include:

a first acquiring module, configured to acquire, according to the scheduling information of the first time synchronization message, a corresponding time slot of the first physical synchronization message received by the physical layer of the air interface;

with,

a first processing module, configured to calculate, according to the local clock and the time slot acquired by the first acquiring module, a start time of the first symbol in the time slot received by the physical layer of the air interface, and use the same as the slave clock device in the air interface physical The layer receives the time Τ _{2 of} the first time synchronization message, or calculates the starting time of the second symbol in the time slot received by the physical layer of the air interface according to the local clock and the time slot acquired by the first acquiring module, It is the time τ ₂ at which the slave clock device receives the first time synchronization message at the air interface physical layer.

The transceiver module 701 is further configured to receive the second time synchronization message sent by the master clock device. The acquiring module 702 is further configured to obtain, by using the second time synchronization message received by the transceiver module 701, the 1\ a timestamp, where the above 1\ is a time when the master clock device sends the first time synchronization message by using the RF;

The transceiver module 701 is further configured to: after receiving the second time synchronization message, to the master clock The device sends a third time synchronization message;

Obtaining module 702 is further configured in accordance with a third time synchronization messages sent by the transceiver module 701, the third acquisition time synchronization message through radio frequency emitted T _3;

In an application scenario, the obtaining module 702 is specifically configured to obtain, according to the scheduling information of the third time synchronization message, a time Τ ₃ sent by the third time synchronization message by using the RF, or send a third time synchronization message through the hardware to send the RF through the RF. The moment Τ ₃ .

In an actual application, the obtaining module 702 can include:

a second acquiring module, configured to obtain, according to the scheduling information of the third time synchronization message, a corresponding time slot sent by the third time synchronization message by using a radio frequency;

with,

a second processing module, configured to calculate, according to the local clock and the time slot acquired by the second processing module, an end time of transmitting the last symbol in the time slot, as a time when the third time synchronization message is sent by using the radio frequency Τ ₃ Or calculating, according to the local clock and the time slot acquired by the second processing module, the start time of transmitting the last symbol in the time slot, as the time τ ₃ sent by the third time synchronization message through the radio frequency, or Calculating, according to the local clock and the time slot acquired by the second processing module, the starting time of transmitting the first symbol in the time slot as the time τ ₃ sent by the third time synchronization message through the radio frequency.

Further, in an application scenario, the transceiver module 701 may be further configured to: after the extension of the 1588 ν2 protocol, send a new message to the master clock device, such as a follow message Follow_up, where the new message carries the slave clock device. The time T ₃ at which the RF issues the third time synchronization message described above.

The transceiver module 701 is further configured to receive a fourth time synchronization message sent by the master clock device, where the acquiring module 702 is further configured to acquire a timestamp of the time Τ ₄ carried in the fourth time synchronization message, where the Τ ₄ is the foregoing The time at which the master clock device receives the third time synchronization message on the physical layer of the air interface;

The processing module 703 is configured to calculate a clock offset from the master clock device according to the foregoing Τ ₂ , Τ _3, and Τ ₄ ;

Specifically, the calculation module 703 can be configured to calculate a message average delay Delay between the master and the slave device according to the following formula, and calculate a clock offset Offset from the master clock device correspondingly: T ₂ = T! + Delay + Offset; T ₄ = T ₃ + Delay-Offset.

The above two formulas can become:

Delay = ( T ₂ - 1\+1> T ₃ ) 12;

Offset= T ₂ - TV Delay, ie Offset= ( T ₂ - TT ₄ + T ₃ ) /2.

The correction module 704 is configured to correct the local clock according to the result calculated by the processing module 703.

According to the calculation result of the processing module 703, the correction module 704 can correct the local clock according to the clock offset Offset, or after the time synchronization message interaction process between the master and slave clock devices, the processing module 703 The values of the plurality of clock offsets Off se t obtained by performing the multiple operations are averaged, and the local clock is corrected based on the average value to achieve time synchronization with the master clock device.

It should be noted that the slave clock device in this embodiment may be used as the slave clock device in the foregoing method embodiment, and may be used to implement all the technical solutions in the foregoing method embodiments, and the functions of the function modules may be according to the foregoing method embodiments. For a specific implementation of the method, reference may be made to the related description in the foregoing embodiments, and details are not described herein again.

It can be seen that, in this embodiment, the obtaining, by the acquiring device 702, the clock device obtains the time T _{2 of the} first time synchronization message received by the physical layer of the air interface, and acquires the time L sent by the third synchronization message by using the radio to obtain the second time synchronization message. The timestamp of 1\ carried in the time and the timestamp of Τ ₄ carried in the fourth time synchronization message; and more accurately calculating the 与\, Τ ₂ , Τ ₃ and Τ ₄ according to the obtained master clock device The clock offset improves the accuracy of the correction of the local clock by the correction module 704 according to the calculation result of the processing module 703, thereby improving the time synchronization accuracy of the master-slave clock device. The embodiment of the present invention further provides a time synchronization system for implementing the time synchronization method described above. A time synchronization system provided by the implementation of the present invention is described below.

Referring to FIG. 8, a time synchronization system according to an embodiment of the present invention includes: Master clock device 801 and slave clock device 802.

The master clock device 801 is configured to send the first time synchronization message to the slave clock device 802, and acquire the time 1\ sent by the first time synchronization message through the RF; send the second time synchronization message to the slave clock device 802, and The second time synchronization message carries a timestamp of 1\; receives the third time synchronization message sent by the slave clock device 802, and acquires the time T ₄ at which the air interface physical layer receives the third time synchronization message; to the slave clock device 802 A fourth time synchronization message is sent, and a timestamp of Τ ₄ is carried in the fourth time synchronization message.

The slave clock device 802 is configured to receive the first time synchronization message sent by the master clock device 801, and acquire the time Τ ₂ when the air interface physical layer receives the first time synchronization message; receive the second time synchronization sent by the master clock device 801. a message, and acquiring a timestamp of the time 1\ carried in the second time synchronization message, where the above 1\ is the time when the primary clock device 801 sends the first time synchronization message by using the RF; and sends the first time to the master clock device 801. And synchronizing the message, and acquiring the time Τ ₃ sent by the third time synchronization message through the RF; receiving the fourth time synchronization message sent by the master clock device 801, and acquiring the time Τ ₄ carried in the fourth time synchronization message stamp, wherein the master clock device 801 Τ ₄ received at the air interface physical layer the third time to the time synchronization message; \, Τ _2, Τ ₃ calculated Τ ₄ and the master clock device 801 based on the clock Î¤ Offset; Corrects its local clock based on the calculated clock offset.

The structure of the master clock device 801 in this embodiment may be a master clock device as shown in FIG. 6. The structure of the slave clock device 802 in this embodiment can be a slave clock device as shown in FIG. It should be noted that the master clock device 801 of the embodiment may be the master clock device in the foregoing method embodiment, and the slave clock device 802 may be the slave clock device in the foregoing method embodiment, which may be used to implement the foregoing method embodiment. For the technical solutions of the present invention, the functions of the various functional modules may be specifically implemented according to the method in the foregoing method embodiments. For the specific implementation process, refer to the related description in the foregoing embodiments, and details are not described herein again.

It can be seen that, in this embodiment, the time synchronization system acquires the time when the time synchronization message is sent by the RF and the time when the physical layer of the air interface receives the time synchronization message, as the time of sending and receiving the time synchronization message, thereby eliminating the physical physics. The effect of delay and jitter of processing such as layer modulation and demodulation on obtaining the accuracy of the transmission and reception time of the time synchronization message, improving the accuracy of acquiring the transmission and reception time of the time synchronization message, and using the higher precision of the acquisition time The transmission and reception time information of the synchronization message is time-synchronized by the master-slave clock device, and the time synchronization accuracy of the master-slave clock device can be improved accordingly.

A person skilled in the art can understand that all or part of the steps of implementing the above embodiments can be completed by a program to instruct related hardware, and the program can be stored in a computer readable storage medium, the above mentioned storage. The medium can be a read only memory, a magnetic disk or a compact disk or the like.

A time synchronization method and related equipment and system provided by the present invention are described in detail above. For those skilled in the art, according to the idea of the embodiment of the present invention, the specific implementation manner and the application range may be changed. In the above, the contents of this specification are not to be construed as limiting the invention.

Claims

Rights request

A time synchronization method, comprising:

The master clock device sends a first time synchronization message to the slave clock device, and acquires a time when the first time synchronization message is sent through the radio frequency.

The master clock device sends a second time synchronization message to the slave clock device, and carries the time stamp of the 1\ in the second time synchronization message;

Master clock device to the transmitting device from a fourth clock time synchronization message, and time stamp carries the Τ ₄ in the fourth time synchronization message to the slave clock device according to claim 1 \ [tau] ₄ and Calculating a clock offset of the slave clock device and the master clock device, and correcting a local clock of the slave clock device according to the calculated clock offset.

2. The method of claim 1 wherein

The obtaining the time when the first time synchronization message is sent by using the radio frequency is specifically: acquiring, according to the scheduling information of the first time synchronization message, the time that the first time synchronization message is sent by using the radio frequency

Alternatively, the time 1\ of the first time synchronization message sent by the radio frequency is recorded by hardware.

3. The method of claim 2, wherein

And obtaining, according to the scheduling information of the first time synchronization message, a time when the first time synchronization message is sent by using a radio frequency, specifically:

Acquiring, according to the scheduling information of the first time synchronization message, a corresponding time slot sent by the first time synchronization message by using a radio frequency;

Calculating, according to the local clock and the time slot, an end time of transmitting the last symbol in the time slot, as a time when the first time synchronization message is sent by using a radio frequency, or calculating according to a local clock and the time slot. And sending a start time of the last symbol in the time slot as a time when the first time synchronization message is sent by using a radio frequency or calculating, according to the local clock and the time slot, sending the time slot The start time of the first symbol is used as the time 1\ of the first time synchronization message sent by the radio frequency.

The method according to claim 1, wherein the acquiring the time T ₄ when the air interface physical layer receives the third time synchronization message is specifically:

Obtaining, according to the scheduling information of the third time synchronization message, a time Τ ₄ when the air interface physical layer receives the third time synchronization message;

Alternatively, the time τ _{4 of} the third time synchronization message is received by the hardware recording air interface physical layer.

5. The method of claim 4, wherein

Obtaining, according to the scheduling information of the third time synchronization message, a time Τ ₄ when the third time synchronization message is received by the air interface physical layer, specifically:

Obtaining, according to the scheduling information of the third time synchronization message, a corresponding time slot in which the air interface physical layer receives the third time synchronization message;

Calculating, according to the local clock and the time slot, a start time at which the air interface physical layer receives the first symbol in the time slot, and receiving, as the master clock device, the third time synchronization at the air interface physical layer. The time of the message Τ ₄ , or calculating, according to the local clock and the time slot, the starting time of the second symbol in the time slot received by the physical layer of the air interface, which is used as the primary clock device in the physical layer of the air interface The time Τ _{4 of} receiving the third time synchronization message.

The method according to any one of claims 1 to 5, wherein the first time synchronization message is time synchronization.

The second time synchronization message is a follow message Follow_up;

The third time synchronization message is a delay request message Delay_Req;

The fourth time synchronization message is a delayed response message Delay_Resp.

7. A time synchronization method, comprising:

Receiving, by the clock device, the first time synchronization message sent by the master clock device, and acquiring the time T ₂ when the air interface physical layer receives the first time synchronization message;

Receiving, by the clock device, a second time synchronization message sent by the master clock device, and acquiring a timestamp carrying 1 in the second time synchronization message, where the 1\ is the primary clock device transmitting through the radio frequency The time of the first time synchronization message;

Transmitting, by the clock device, the third time synchronization message to the master clock device, and acquiring a time Τ ₃ that the third time synchronization message is sent by using the radio frequency; Receiving, by the clock device, a fourth time synchronization message sent by the master clock device, and acquiring a timestamp of τ ₄ carried in the fourth time synchronization message, where the τ ₄ is the air interface of the master clock device a time at which the third time synchronization message is received on the physical layer;

Calculating, by the clock device, a clock offset of the slave clock device and the master clock device according to the 1\, τ ₂ , τ _3, and τ ₄ ;

The method according to claim 7, wherein the acquiring the time Τ _{2 of} the first time synchronization message by the physical layer of the air interface is specifically:

Obtaining, according to the scheduling information of the first time synchronization message, a time Τ ₂ at which the air interface physical layer receives the first time synchronization message;

Alternatively, the time τ _{2 of} the first time synchronization message is received by the hardware recording air interface physical layer.

9. The method of claim 8 wherein:

And obtaining, according to the scheduling information of the first time synchronization message, a time Τ ₂ that is received by the air interface physical layer, where the first time synchronization message is, specifically:

Obtaining, according to the scheduling information of the first time synchronization message, a corresponding time slot of the first physical synchronization message received by the air interface physical layer, and calculating, according to the local clock and the time slot, that the air interface physical layer receives the time slot The start time of the first symbol is used as the time Τ _{2 of} the slave clock device receiving the first time synchronization message at the air interface physical layer, or the air interface physical layer is calculated according to the local clock and the time slot. Receiving a start time of the second symbol in the time slot as a time Τ ₂ when the slave clock device receives the first time synchronization message at the air interface physical layer.

The method according to claim 7, wherein the acquiring the time Τ ₃ sent by the third time synchronization message by using a radio frequency is specifically:

Obtaining, according to the scheduling information of the third time synchronization message, a time Τ ₃ sent by the third time synchronization message by using a radio frequency;

Alternatively, the time Τ ₃ sent by the radio frequency of the third time synchronization message is recorded by hardware.

11. The method of claim 10, wherein Obtaining, according to the scheduling information of the third time synchronization message, the time T ₃ sent by the third time synchronization message by using a radio frequency, specifically:

Obtaining, according to the scheduling information of the third time synchronization message, a corresponding time slot sent by the third time synchronization message by using a radio frequency, and calculating, according to the local clock and the time slot, sending an end of the last symbol in the time slot. At the moment, as the time τ _{3 of} the third time synchronization message sent by the radio frequency, or calculating the starting time of transmitting the last symbol in the time slot according to the local clock and the time slot, The third time synchronization message passes the time τ ₃ sent by the radio frequency, or calculates the starting time of transmitting the first symbol in the time slot according to the local clock and the time slot, and uses the third time as the third time synchronization message. The time synchronization message is sent through the radio frequency τ ₃ .

12. A master clock device, comprising:

a transceiver module, configured to send a first time synchronization message to the slave clock device;

An acquiring module, configured to acquire, when the transceiver module sends the first time synchronization message by using a radio frequency

The transceiver module is further configured to send a second time synchronization message to the slave clock device, and carry the time stamp of the 1\ in the second time synchronization message;

The transceiver module is further configured to receive a third time synchronization message sent by the slave clock device;

The acquiring module is further configured to obtain, according to the third time synchronization message received by the transceiver module, a time τ ₄ at which the air interface physical layer receives the third time synchronization message;

The transceiver module is further configured to send a fourth time synchronization message to the slave clock device, and carry a timestamp of the τ ₄ in the fourth time synchronization message, so that the slave clock device is configured according to the \ and τ ₄ calculate a clock offset of the slave clock device and the master clock device, and correct the local clock of the slave clock device according to the calculated clock offset.

13. The master clock device according to claim 12, wherein:

The obtaining module is specifically configured to: acquire, according to the scheduling information of the first time synchronization message, a time when the first time synchronization message is sent by using a radio frequency or a time when the first time synchronization message is sent by using a hardware to send the radio through the radio frequency? .

The master clock device according to claim 13, wherein the acquiring module comprises: The obtaining module 1 is configured to obtain, according to the scheduling information of the first time synchronization message, a corresponding time slot sent by the first time synchronization message by using a radio frequency;

The processing module 1 is configured to calculate, according to the local clock and the time slot acquired by the acquiring module, an end time of sending the last symbol in the time slot, and use the time as the time when the first time synchronization message is sent by using the radio frequency. 1 or, according to the local clock and the time slot acquired by the acquiring module, calculate a starting time of sending the last symbol in the time slot, and use it as the time when the first time synchronization message is sent through the radio frequency. Or calculating, according to the local clock and the time slot acquired by the acquiring module, the starting time of sending the first symbol in the time slot, and using it as the time 1 of the first time synchronization message sent by the radio frequency. .

15. The master clock device of claim 12, wherein

The acquiring module is specifically configured to: acquire, according to the scheduling information of the third time synchronization message, a time T ₄ when the third time synchronization message is received by the air interface physical layer; or receive the foregoing by using a hardware recording air interface physical layer The time of the three-time synchronization message Τ ₄ .

The master clock device according to claim 15, wherein the acquiring module comprises:

The obtaining module 2 is configured to obtain, according to the scheduling information of the third time synchronization message, a corresponding time slot of the air interface physical layer to receive the third time synchronization message;

The processing module 2 is configured to calculate, according to the local clock and the time slot acquired by the acquiring module 2, a start time of the first symbol in the time slot received by the air interface physical layer, and use the same as the primary clock device. The time at which the air interface physical layer receives the third time synchronization message Τ ₄ , or calculates the start of the second symbol in the time slot received by the physical layer of the air interface according to the local clock and the acquisition module 2 At the moment, it is used as the time Τ ₄ when the master clock device receives the third time synchronization message at the air interface physical layer.

17. A slave clock device, comprising:

a transceiver module, configured to receive a first time synchronization message sent by the master clock device, and an acquiring module, configured to acquire, according to the first time synchronization message received by the transceiver module, the air interface physical layer to receive the first time synchronization message Time Τ ₂ ;

The transceiver module is further configured to receive a second time synchronization message sent by the primary clock device, where the second time synchronization message carries a timestamp of 1\; The acquiring module is further configured to obtain, from the second time synchronization message received by the transceiver module, a timestamp of the first time synchronization message carrying 1\, where the 1\ is the primary clock device The time at which the first time synchronization message is sent by the radio frequency;

The transceiver module is further configured to send a third time synchronization message to the master clock device, where the acquiring module is further configured to: according to the third time synchronization message sent by the transceiver module, obtain the third synchronization message by using a radio frequency Time τ ₃ ;

The transceiver module is further configured to receive a fourth time synchronization message sent by the master clock device;

The acquiring module is further configured to acquire a timestamp of τ ₄ carried in the fourth time synchronization message, where the τ ₄ is that the primary clock device receives the third time synchronization message on an air interface physical layer. Moment

a processing module, configured to calculate a clock offset between the slave clock device and the master clock device according to 1\, τ ₂ , τ _{3 ,} and τ ₄ acquired by the acquiring module;

And a correction module, configured to modify a local clock of the slave clock device according to the clock offset calculated by the processing module.

18. The slave clock device of claim 17, wherein

The acquiring module is specifically configured to: acquire, according to the scheduling information of the first time synchronization message, a time Τ ₂ when the air interface physical layer receives the first time synchronization message; or receive the foregoing by using a hardware recording air interface physical layer The time of the synchronization message at a time Τ ₂ .

The slave clock device according to claim 18, wherein the acquiring module comprises:

a first acquiring module, configured to acquire, according to the scheduling information of the first time synchronization message, a corresponding time slot in which the air physical layer receives the first time synchronization message;

a first processing module, configured to calculate, according to the local clock and the time slot acquired by the first acquiring module, a start time of the first symbol in the time slot received by the air interface physical layer, and use the same as the slave clock The device receives the first time synchronization message at the air interface physical layer, Τ ₂ , or calculates, according to the local clock and the time slot acquired by the first acquiring module, that the air interface physical layer receives the second of the time slots. The start time of the symbols as the time Τ ₂ at which the slave clock device receives the first time synchronization message at the air interface physical layer.

20. The slave clock device of claim 17, wherein

The scheduling information obtaining module for time synchronization based on the third message, the third time acquisition time synchronization message sent by a radio frequency T _3; or emitted by the radio frequency hardware of the third recording time synchronization message The moment Τ ₃ .

The slave clock device according to claim 20, wherein the acquiring module comprises:

a second acquiring module, configured to acquire, according to the scheduling information of the third time synchronization message, a corresponding time slot sent by the third time synchronization message by using a radio frequency;

a second processing module, configured to calculate, according to the local clock and the time slot acquired by the second acquiring module, an end time of sending the last symbol in the time slot, and send the third time synchronization message as a third time synchronization message by using a radio frequency Time Τ ₃ , or calculating a start time of transmitting the last symbol in the time slot according to the local clock and the time slot acquired by the second acquiring module, and transmitting the same as the third time synchronization message Sending a time Τ ₃ , or calculating a starting time of transmitting the first symbol in the time slot according to the local clock and the time slot acquired by the second acquiring module, as the third time synchronization message The time elapsed by the radio frequency Τ ₃ .

22. A time synchronization system, comprising:

a master clock device, configured to send a first time synchronization message to the slave clock device, and obtain a second time synchronization message sent to the slave clock device by the time when the first time synchronization message is sent by using the radio frequency, and in the second The time synchronization message carries the timestamp of the 1\; receives the third time synchronization message sent by the slave clock device, and acquires the time Τ ₄ when the air interface physical layer receives the third time synchronization message; transmitting a fourth message from the clock device time synchronization, and carries the stamp Τ ₄ in the fourth time synchronization message;

a slave clock device, configured to receive a first time synchronization message sent by the master clock device, and acquire a time Τ ₂ when the air interface physical layer receives the first time synchronization message; receive a second message sent by the master clock device Time synchronization message, and acquiring a timestamp of time 1\ carried in the second time synchronization message, where 1\ is a time when the primary clock device sends the first time synchronization message by using a radio frequency; The clock device sends a third time synchronization message, and acquires a time Τ ₃ sent by the third time synchronization message through the radio frequency; receives a fourth time synchronization message sent by the primary clock device, and acquires the fourth time synchronization message. The timestamp of the time Τ ₄ carried in, T ₄ at which the device receives the master clock on the air interface physical layer time synchronization message to the third time; according to the 1 \, τ _2, τ ₃ and τ ₄ of the computing device and the master clock from the clock The clock offset of the device; correcting the local clock of the slave clock device according to the calculated clock offset.