CN103684731A - Time synchronizing method - Google Patents
Time synchronizing method Download PDFInfo
- Publication number
- CN103684731A CN103684731A CN201310229972.3A CN201310229972A CN103684731A CN 103684731 A CN103684731 A CN 103684731A CN 201310229972 A CN201310229972 A CN 201310229972A CN 103684731 A CN103684731 A CN 103684731A
- Authority
- CN
- China
- Prior art keywords
- time
- entity
- accuracy
- synchronized
- synchronizing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L7/00—Arrangements for synchronising receiver with transmitter
- H04L7/04—Speed or phase control by synchronisation signals
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L12/40052—High-speed IEEE 1394 serial bus
- H04L12/40091—Bus bridging
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L2012/40267—Bus for use in transportation systems
- H04L2012/40273—Bus for use in transportation systems the transportation system being a vehicle
Landscapes
- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Synchronisation In Digital Transmission Systems (AREA)
- Small-Scale Networks (AREA)
- Electric Clocks (AREA)
Abstract
The present invention relates to a time synchronizing method which can implement time synchronization through a small amount of information in Ethernet communication. The time synchronizing method is used for implementing time synchronization in Ethernet communication. The time synchronizing method comprises the following implementing steps: (a) step, from initial power supply to number K of times of power supply, implementing time synchronization on time synchronization information which is received and transmitted among all entities that take part in time synchronization; and (b) step, when the number of times of power supply reaches (K+1), determining time accuracy of each entity by means of time synchronizing information which is acquired until the K time, and in the time accuracies, eliminating a certain entity with lowest time accuracy from the time synchronization, and implementing time synchronization. The time synchronizing method of the invention can reduce information which is transmitted and received on Ethernet communication network.
Description
Technical field
The present invention relates to method for synchronizing time, be specifically related to small amount information, implement the method for synchronizing time of time synchronized in ethernet communication.
Background technology
Ethernet (Ethernet) is the communication standard that utilizes the Local Area Network of bus structures mode.The communication standard of ethernet communication has 802.1 etc.
While utilizing ethernet communication to transmit information, need time synchronized process.Time can not be synchronous, when the image that each camera of installing as the place ahead of vehicle, rear, left side and right side captures is presented at a picture, and can time of origin difference between each image display frame.Time of origin difference, makes troubles to driver or user, and error message is provided.Driver also can be thinking four different images with the same image that four View show.
The time synchronized process of the ethernet communication of described 802.1 modes is summarized as follows: all entities (Entity) that are connected with localized network (Local Network) all participate in time synchronized.At ethernet communication, except essential information, between object, transmitting-receiving is intended to the information of time synchronized.In the time synchronization information of transmitting-receiving, select to have entity of accurate clock and provide as GrandMaster the time that can be used as other entity benchmark.
In localized network that described existing time synchronizing method is ethernet communication, all entities all participate in time synchronized and cause the waste of Internet resources.Especially, existing time synchronizing method is that network is more complicated, and the amount of information of receiving and dispatching for time synchronized can be how much numbers growths.
Summary of the invention
For solving described problem, the invention provides a kind of entity that is chosen as GrandMaster from physical characteristic is also the highest factor of possibility that is chosen as GrandMaster in next time synchronized, reducing to greatest extent at Ethernet is the information of time synchronized transmitting-receiving, to reduce the method for synchronizing time of network occupation rate.
For solving described problem, the invention provides a kind of method for synchronizing time, the method is the method for interval step as in Ethernet (Ethernet) communication time, implementation step comprises: (a) step, till supplying power at first power supply number of times reaches the number of times K having set, utilize the time synchronization information of transmitting-receiving between all entities (Entity) that participate in time synchronized to implement time synchronized; (b) step, during power supply number of times K+1, utilize the time accuracy that judges each entity by the time synchronization information of described K collection, from described time accuracy, some in the minimum described entity of time accuracy got rid of from described time synchronized, and implemented described time synchronized.
Preferably, method for synchronizing time according to claim 1, the judgement of described time accuracy is clock frequency (Clock Ration) judgement that utilizes described entity.
Preferably, described (b) step is repeatedly to implement, until be used in the described entity of described time synchronized, becomes two.
Preferably, described method for synchronizing time comprises: (c) step, and described time accuracy and before differing by more than between time accuracy have been set while differing, and the described time synchronization information of the entity that recycling is finally excluded is implemented described time synchronized.
Beneficial effect of the present invention is to reduce the information of receiving and dispatching for time synchronized on ethernet communication network.
Accompanying drawing explanation
Fig. 1 means the diagram of an example of vehicle ethernet communication system of the Applicative time synchronous method of the preferred embodiment of the present invention;
Fig. 2 is the diagram of the first process of the method for synchronizing time of the explanation preferred embodiment of the present invention;
Fig. 3 is the diagram of the second process of the method for synchronizing time of the explanation preferred embodiment of the present invention;
Fig. 4 is the diagram of the 3rd process of the method for synchronizing time of the explanation preferred embodiment of the present invention;
Fig. 5 is the diagram of the 4th process of the method for synchronizing time of the explanation preferred embodiment of the present invention;
Fig. 6 is the diagram of the 5th process of the method for synchronizing time of the explanation preferred embodiment of the present invention.
Embodiment
With reference to the accompanying drawings, invention preferred embodiment is described in detail.The same member of reality in description and accompanying drawing is to represent with same symbol, no longer repeat specification.And explanation is when of the present invention, if aim of the present invention is thickened to illustrating of relevant known function or structure, omits this explanation.
Describe that some members " are connected in " or " being connected in " other member, be likely directly connected in or be connected in this other member, but likely have other member in the middle of should being understood as that.On the contrary, describe that some members " are directly connected in " or " being directly connected in " other member, in the middle of should being understood as that, do not have other member.
Singulative in this specification does not have, under the prerequisite of special suggestion, to comprise plural form in sentence yet." the comprising (comprises) " of using in specification or " (comprising) that comprise " do not get rid of the existence of more than one other member, step, action and/or element beyond related member, step, action and/or element or supplement.
The method for synchronizing time of the preferred embodiment of the present invention is, the physical characteristics of oscillating element, the entity (Entity) that is chosen as the GrandMaster that becomes time synchronizing standard is very high in the possibility that is after this chosen as GrandMaster, and it is very low in after this selected possibility not to be chosen as the entity of GrandMaster.Therefore the present invention utilizes this possibility, is reduced to the information of time synchronized transmitting-receiving and promotes the expenditure of answering of Internet resources.Described GrandMaster refers to the entity with the sensitiveest temporal information.
The method for synchronizing time of the preferred embodiment of the present invention of explanation is that the bridge that can take four cameras being installed by vehicle front, rear, left side and right side and have memory function forms ethernet communication system and describes as example together by reference to the accompanying drawings, but be not limited to vehicle communication, in ethernet communication, need all can utilizing of time synchronized process.
Fig. 1 means the diagram of an example of vehicle ethernet communication system of the Applicative time synchronous method of the preferred embodiment of the present invention.According to Fig. 1, vehicle ethernet communication system comprises rear camera 110, the place ahead camera 120, right side camera 130, left side camera 140, bridge 150 and acceptance division 160.
Rear camera 110 is cameras of taking rear view of vehicle region, and the place ahead camera 120 is cameras of taking vehicle front region.
Bridge 150 is to receive photographic images information from rear camera 110, the place ahead camera 120, right side camera 130 and left side camera 140, as the information that is intended to time synchronized, and the timestamp (Time Stamp) of transmitting-receiving hardware or software value.Bridge 150 supports storage to be intended to receive and dispatch memory (Memory) function of the information of time synchronized.
Bridge 150 is implemented time synchronized with rear camera 110, the place ahead camera 120, right side camera 130 and left side camera 140, after the photographic images information that time synchronized is completed is synthetic, is sent to acceptance division 160.
Acceptance division 160 is to be received in bridge 150 to complete synchronous composograph information, and acceptance division 160 can be audio-video network (AVN, Audio Video Network).
The entity using in explanation of the present invention (Entity) refers to the object that needs time synchronized on network.In Fig. 1, rear camera 110, the place ahead camera 120, right side camera 130, left side camera 140 and bridge 150 become entity.
Solid line in Fig. 1 between camera and bridge 150 is the image information that is transmitted in bridge 150 after camera collection.Dotted line between camera and bridge 150 is the time synchronization information of receiving and dispatching for time synchronized between entity.
Under regard to the method for synchronizing time process of the preferred embodiment of the present invention an example describe.At the initial all entities before K time of powering, all participate in time synchronized.K is that all entities participate in considering in the synchronous process of grasping accuracy the accuracy of synchronizing information and efficiency and the number of times that arranges.For example, K time number of times is more, higher to the accuracy of synchronizing information, but the application efficiency of Internet resources can decline, and therefore can be set to three times left and right.
Bridge 150 is to participate in to all entities till initial power supply K time the statistical value that time synchronized obtain, and starts power supply each time just can from synchronous, eliminating have the entity of clock (Clock) least accurately from K+1 time.The entity that the process that the entity of participation time synchronized is excluded can be carried out up to participation time synchronized only has one.But be not to participate in process that the entity of time synchronized is excluded must be carried out up to the entity that participates in time synchronized and become one, can be set to two or three.
Bridge 150 is to compare start the accuracy of the time of the lasting GrandMaster inputting from initial power supply.The time accuracy that relatively participates in an entity of time synchronized in the process of Time precisions at bridge 150 is compared difference with existing time accuracy and is less than the standard of having set, and time synchronized continues only to utilize an entity.
But bridge 150 is in the process of accuracy that compares the time, the difference that the time accuracy of an entity of participation time synchronized is compared with existing time accuracy is greater than the standard of having set, and can make the entity of getting rid of recently participate in time synchronized.When the entity that makes to get rid of recently participates in powering after time synchronized again, if participate in the entity of time synchronized, reach more than one, bridge 150 can be got rid of and has the entity of clock least accurately from time synchronized.And the entity that makes to get rid of recently while participating in powering after time synchronized next time too, if time accuracy is compared difference with existing time accuracy and is greater than the standard of having set, bridge 150 can make next high entity of time accuracy participate in time synchronized.
Fig. 2 is the diagram of the first process of the method for synchronizing time of the explanation preferred embodiment of the present invention.Fig. 3 is the diagram of the second process of the method for synchronizing time of the explanation preferred embodiment of the present invention.Fig. 4 is the diagram of the 3rd process of the method for synchronizing time of the explanation preferred embodiment of the present invention.Fig. 5 is the diagram of the 4th process of the method for synchronizing time of the explanation preferred embodiment of the present invention.Fig. 6 is the diagram of the 5th process of the method for synchronizing time of the explanation preferred embodiment of the present invention.
Below in conjunction with Fig. 2 to Fig. 6, the method for synchronizing time of the preferred embodiment of the present invention is implemented time synchronized process by vehicle ethernet communication system applies describes.
According to Fig. 2, for all entities till initial power supply K time all participate in time synchronized, rear camera 110, the place ahead camera 120, right side camera 130 and left side camera 140 transmit and outside image informations, go back delivery time synchronizing information to bridge 150.
Bridge 150 utilizes the time synchronization information judgement time accuracy receiving.Specifically, bridge 150 utilizes the accuracy of clock frequency (Clock Ratio) the judgement time of each entity.Clock frequency is to utilize the timestamp (Time-Stamp) occurring on software and hardware, and the time accuracy of typical hardware is more outstanding than software, therefore can utilize emphatically hardware timestamping.
In Fig. 1 to Fig. 6 by the time accuracy of five entities of 0 to 4 demonstration.Numeral is less, and time accuracy is higher, and the 4th, the entity that time accuracy is minimum, 0 is the highest entity of time accuracy.
In Fig. 2, according to bridge 150, to the time synchronization information statistics receiving till initial power supply three times, bridge 150 can judge that the time accuracy of bridge 150 is the highest, and the time accuracy of left and right camera 140 is minimum.
According to Fig. 3, during four power supplies, bridge 150 is got rid of the left side camera 140 that in Fig. 2, time accuracy is minimum from time synchronized process.Therefore left side camera 140 and bridge 150 do not need transmitting-receiving to be intended to the time synchronization information of time synchronized thereafter.
According to Fig. 4, during five power supplies, participating in the synchronous entity of current time is that four entities are rear camera 110, the place ahead camera 120, right side camera 130 and bridge 150.More than an entity.Therefore, the left side camera 140 that bridge 150 is got rid of by time synchronized in Fig. 3, from four entities of participation time synchronized, the minimum right side camera 130 of time accuracy is got rid of from time synchronized process.Bridge 150 is got rid of right side camera 130 in time synchronized process, and after this right side camera 130 and bridge 150 do not need to receive and dispatch time synchronization information.
According to Fig. 5, while participating in six power supplies, participating in the synchronous entity of current time is three rear cameras 110, the place ahead camera 120 and bridge 150.More than an entity.Therefore bridge 150 is got rid of the minimum the place ahead camera 120 of time accuracy from three entities of participation time synchronized from time synchronized process.Bridge 150 is got rid of the place ahead camera 120 in time synchronized process, after this between bridge 150 and the place ahead camera 120, does not need to receive and dispatch synchronizing information.
According to Fig. 6, the entity that participates in current time synchronized during seven power supplies is two rear cameras 110 and bridge 150.More than an entity.Therefore bridge 150 is got rid of the rear camera 110 that time accuracy is low from rear camera 110 and bridge 150, only utilizes the time synchronization information of bridge 150 to implement time synchronized.If the time accuracy of bridge 150 is 1, the time accuracy of rear camera 110 is 0, and 150 of bridges utilize the time synchronization information of rear camera 110 to implement time synchronized.
Bridge 150 judgements are implemented time synchronized with an entity and can be caused accuracy to reduce, and in time synchronized process, can from the entity of getting rid of, make the entity that time accuracy is the highest participate in time synchronized process.
Specifically, the time accuracy that 150 pairs of plans of bridge are chosen to be in the former number of times of record on the entity time accuracy of GrandMaster and bridge 150 compares.Time accuracy in number of times is stored in the highest time accuracy in the time accuracy of bridge 150 in number of times before referring to before.Thereupon, during seven power supplies, the time accuracy in number of times refers to time accuracy the highest while powering for six times before.
Be chosen as record on the time accuracy of entity of GrandMaster and bridge 150 before time accuracy in number of times differ the standard of having set that is less than, selected GrandMaster is still decided to be to GrandMaster, differ by more than the standard of having set, in the entity that bridge 150 can be excluded from time synchronized process, make the entity that time accuracy is the highest participate in time synchronized process.
The standard of having set is to be set as clock frequency 5 degree, and described setting meeting occurs change according to the accuracy requiring in system, network environment, equipment performance etc.
While differing by more than established standards, judge GrandMaster time, accuracy was inaccurate time, the rear camera 110 that makes entity that time accuracy is the highest get rid of in time synchronized recently from the entity of getting rid of participates in time synchronized process again.
Bridge 150 is to make rear camera 110 again participate in time synchronized process and implement time synchronized process still to judge when the time, accuracy was inaccurate, makes the place ahead camera 120 that time accuracy is high thereafter again participate in time synchronized process.
In other words when the method for synchronizing time of the preferred embodiment of the present invention is only synchronous by an entity enforcement correct time as shown in Figure 6, from the viewpoint of efficiency of network resources, be optimal.But because equipment is outmoded, the judgement such as noise, environmental impact cannot be only implements correct time when synchronous with an entity, the entity that makes to be got rid of one by one participates in time synchronized process and with the form enforcement time synchronized process of Fig. 2 to Fig. 5.And first with the form of Fig. 2 to Fig. 5, implement time synchronized process and then implement synchronized process with the form of Fig. 6.
According to the present invention, can reduce the information of receiving and dispatching for time synchronized on ethernet communication network.
Above embodiment and accompanying drawing only, in order to technical scheme of the present invention to be described, are not intended to limit; Although the present invention is had been described in detail with reference to previous embodiment, those of ordinary skill in the art is to be understood that: it still can be modified to the technical scheme described in aforementioned each embodiment, or part technical characterictic is wherein equal to replacement; And these modifications or replacement do not make the essence of appropriate technical solution depart from the scope of technical scheme described in various embodiments of the present invention.Protection scope of the present invention should make an explanation according to following claim scope, and all technical schemes in its equal scope should all belong to claim scope of the present invention.
Claims (4)
1. a method for synchronizing time, the method as time synchronized in ethernet communication, is characterized in that, the implementation step of the method comprises:
(a) step, till supplying power at first power supply number of times reaches the number of times K having set, utilizes the time synchronization information of receiving and dispatching between all entities that participate in time synchronized to implement time synchronized;
(b) step, during power supply number of times K+1, utilize the time accuracy that judges each entity by the time synchronization information of described K collection, from described time accuracy, some in the minimum described entity of time accuracy got rid of from described time synchronized, and implemented described time synchronized.
2. method for synchronizing time according to claim 1, is characterized in that,
Described time accuracy is to utilize the clock frequency of described entity to judge.
3. method for synchronizing time according to claim 1, is characterized in that,
Described (b) step is implemented repeatedly, until be used in the described entity of described time synchronized, becomes two.
4. method for synchronizing time according to claim 3, is characterized in that,
Described method for synchronizing time also comprises:
(c) step, described time accuracy and before differing by more than between time accuracy have been set while differing, and the described time synchronization information of the entity that recycling is finally excluded is implemented described time synchronized.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR1020120106623A KR101933366B1 (en) | 2012-09-25 | 2012-09-25 | Time Synchronization Method |
| KR10-2012-0106623 | 2012-09-25 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103684731A true CN103684731A (en) | 2014-03-26 |
| CN103684731B CN103684731B (en) | 2018-04-20 |
Family
ID=50321131
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310229972.3A Active CN103684731B (en) | 2012-09-25 | 2013-06-09 | Method for synchronizing time |
Country Status (2)
| Country | Link |
|---|---|
| KR (1) | KR101933366B1 (en) |
| CN (1) | CN103684731B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021147044A1 (en) * | 2020-01-22 | 2021-07-29 | 华为技术有限公司 | Time-sensitive network time synchronization method and apparatus |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101207606A (en) * | 2006-12-18 | 2008-06-25 | 华为技术有限公司 | Method and apparatus for main clock selecting |
| US20080175275A1 (en) * | 2007-01-22 | 2008-07-24 | Samsung Electronics Co., Ltd. | Time synchronization method between nodes in network and apparatus for implementing the same |
| CN102263631A (en) * | 2011-08-10 | 2011-11-30 | 瑞斯康达科技发展股份有限公司 | Method and clock node for determining master clock within 1588 clock domain |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR100308704B1 (en) | 1996-07-04 | 2001-10-19 | 모리시타 요이찌 | Multiplexed data producing apparatus, encoded data reproducing apparatus, clock conversion apparatus, encoded data recording medium, encoded data transmission medium, multiplexed data producing method, encoded data reproducing method, and clock conversion method |
-
2012
- 2012-09-25 KR KR1020120106623A patent/KR101933366B1/en active IP Right Grant
-
2013
- 2013-06-09 CN CN201310229972.3A patent/CN103684731B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101207606A (en) * | 2006-12-18 | 2008-06-25 | 华为技术有限公司 | Method and apparatus for main clock selecting |
| US20080175275A1 (en) * | 2007-01-22 | 2008-07-24 | Samsung Electronics Co., Ltd. | Time synchronization method between nodes in network and apparatus for implementing the same |
| CN102263631A (en) * | 2011-08-10 | 2011-11-30 | 瑞斯康达科技发展股份有限公司 | Method and clock node for determining master clock within 1588 clock domain |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2021147044A1 (en) * | 2020-01-22 | 2021-07-29 | 华为技术有限公司 | Time-sensitive network time synchronization method and apparatus |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103684731B (en) | 2018-04-20 |
| KR101933366B1 (en) | 2018-12-28 |
| KR20140039853A (en) | 2014-04-02 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN111385048B (en) | Time synchronization method and system | |
| CN101882990B (en) | Method for selecting master clock based on PTP (Picture Transfer Protocol) and link quality, slave clock and system | |
| US20080031283A1 (en) | Time synchronization for network aware devices | |
| CN101364863B (en) | Time synchronizing method, apparatus and system for master, slave time clock side in synchronous network | |
| CN105323054B (en) | Clock synchronizing method and device | |
| CN109951890B (en) | Data communication method, relay node, terminal node and communication system | |
| CN103563287B (en) | Synchronization device and synchronization method | |
| CN105577308A (en) | Method and apparatus for providing in-vehicle network time synchronization using redundant grandmaster | |
| EP3955528B1 (en) | Delay measurement method, system and storage medium | |
| CN104375789A (en) | Synchronous displaying method and system of tiled display screen | |
| CN109981206A (en) | Time synchronization method, device, system and terminal device, storage medium | |
| CN105515708B (en) | A kind of clock synchronization accuracy test device and method based on FC networks | |
| KR20120035199A (en) | Method and system for bearing time synchronization protocol in optical transport network | |
| CN110784747A (en) | Synchronous playing method of advertisement player | |
| DE102015210790B4 (en) | Method and apparatus for synchronizing camera shutters in an in-vehicle Ethernet communications network | |
| CN109996325B (en) | Clock synchronization system and method of wireless sensor network | |
| CN107786293A (en) | Method for synchronizing time, clock equipment, from clockwork and clock synchronization system | |
| CN103166792A (en) | Line asymmetrical compensation method, equipment and system | |
| KR20210070746A (en) | Method and Apparatus for Synchronizing Camera Image Based on GM Clock Time Information | |
| CN114401067A (en) | Time synchronization method for ring network communication, programmable gate array and ring network communication system | |
| CN114070447A (en) | Clock correction method and device based on target wake-up time | |
| CN102195769A (en) | Clock synchronization method for automobile CAN (Control Area Network) | |
| WO2023280206A1 (en) | Systems and methods for camera synchronization | |
| WO2018027704A1 (en) | Time synchronization method and device | |
| CN108964825A (en) | Calibration method, correction device and time server |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |