CN104717030A

CN104717030A - Time synchronization method and corresponding equipment and system

Info

Publication number: CN104717030A
Application number: CN201310693681.XA
Authority: CN
Inventors: 李晗; 张德朝; 王世光; 韩柳燕; 耿亮; 程伟强
Original assignee: China Mobile Communications Group Co Ltd
Current assignee: China Mobile Communications Group Co Ltd
Priority date: 2013-12-17
Filing date: 2013-12-17
Publication date: 2015-06-17
Anticipated expiration: 2033-12-17
Also published as: CN104717030B

Abstract

The invention discloses a time synchronization method and corresponding equipment and system. The time synchronization method comprises the steps that an optical network unit receives a first time synchronization message sent by a downlink small type base station, and the first time synchronization message carries a time synchronization signal acquired by the small type base station from a macro base station; a synchronous reference source used for conducting time synchronization on each downlink small type base station is determined from the received time synchronization signal carried by the first time synchronization message; time synchronization is conducted on the downlink small type base stations according to the determined synchronous reference source. According to the time synchronization method and corresponding equipment and system, by the adoption of the technical scheme, the problems that in the prior art, the synchronization accuracy between the small type base stations is lower and the reliability of the time synchronization is poor can be solved.

Description

Method for synchronizing time and relevant device, system

Technical field

The present invention relates to communication technical field, particularly relate to a kind of method for synchronizing time and relevant device, system.

Background technology

Small base station is supplementing of macro base station network and extends, and it mainly provides wireless access by the small base station be placed in subscriber household or office for user, to improve the in-door covering effect of user, promotes the experience of user.Need stringent synchronization in time between small base station, to avoid interference, and improve link capacity and the communication quality of user.

Wherein, small base station mainly comprises miniature (Micro) base station, nanometer (Nano) base station, femto base station (Pico), femto (Femto) base station etc.

When Scaledeployment small base station, because deployed position is low, dispose quantity greatly, therefore passive optical-fiber network (Passive Optical Network, PON) is the desirable return network of small base station.

PON technology realizes intelligent acess (Fiber To The X, FTTx) mainstream technology, typical PON system is by local side apparatus optical line terminal (Optical Line Terminal, OLT), ustomer premises access equipment optical network unit (Optical Network Unit, ONU) and Optical Distribution Network (Optical DistributionNetwork, ODN) composition.As shown in Figure 1, be PON system Organization Chart.Wherein, " passive " to refer in ODN not containing any active electronic device and electronic power supply, all by optical fiber and light divide/Passive Optical Components such as mixer forms.

Can adopt the time synchronized that air interface synchronization mode realizes between small base station at present, concrete, each small base station adjusts the internal clocking of self by the time synchronizing signal of intercepting macro base station around, thus it is synchronous to realize between each small base station.If but the time signal not having macro base station or small base station to listen to around small base station is more weak, then just can not time synchronized be realized between each small base station.

But when Scaledeployment small base station, there is following defect in above-mentioned air interface synchronization mode:

1, for the region of concentrated deployment, only have part small base station directly can listen to the time synchronizing signal of macro base station by eating dishes without rice or wine in usual region, other small base stations then need acquisition time synchronizing signal from the small base station of the time synchronizing signal that can listen to macro base station, therefore, time synchronizing signal needs just can be delivered to small base station by more synchronous jumping figure, and synchronous jumping figure is more, error is larger, and the synchronization accuracy therefore between each small base station is lower.

2, for the region of scattered deployment, need small base station directly can listen to the time synchronizing signal of macro base station, add the deployment difficulty of small base station, if small base station directly can not listen to the time synchronizing signal of macro base station, small base station is just needed to adopt global positioning system (GPS, Global PositioningSystem) carry out acquisition time synchronizing signal, and be in the impact of indoor small base station due to penetration loss, not easily directly obtain the time synchronizing signal of GPS, the synchronization accuracy therefore between each small base station is lower.

If PON is the return network of small base station, then can transmit 1588v2 time synchronizing signal by PON to small base station, but when the synchronous fault of single OLT or PON mouth time of occurrence, time synchronized cannot be carried out in great quantity of small base station under this OLT or this PON mouth, have impact on the normal work of small base station, therefore make the reliability of the time synchronized between small base station poor.

In prior art, realize the time synchronized between small base station according to air interface synchronization mode, then in the region of concentrated deployment, because the synchronous jumping figure of time synchronizing signal is many, therefore cause synchronization accuracy lower, in the region of scattered deployment, add the deployment difficulty of small base station.Transmit to small base station the time synchronized that 1588v2 time synchronizing signal realizes between small base station according to PON, then when the synchronous fault of single OLT or PON mouth time of occurrence, time synchronized cannot be carried out in great quantity of small base station under this OLT or this PON mouth, have impact on the normal work of small base station, therefore make the reliability of the time synchronized between small base station poor.

In view of this, the embodiment of the present invention proposes, when PON is the return network of small base station, after the small base station of the ONU second line of a couplet gets the time synchronizing signal of macro base station, the time synchronizing signal got is carried in very first time sync message and reports ONU, ONU chooses reference synchronization source in the time synchronizing signal received, and then carries out time synchronized according to each small base station of reference synchronization source to the second line of a couplet chosen.Therefore, when carrying out time synchronized between small base station, only need the time synchronizing signal of the reception macro base station that guarantee section small base station can be good, significantly reduce the deployment difficulty of small base station, and extend adaptation scene, even if part small base station directly can not receive the time synchronizing signal of macro base station, also time synchronized is carried out in the reference synchronization source can chosen according to ONU, without the need to from other small base stations or from GPS acquisition time synchronizing signal, effectively improve the timing tracking accuracy between small base station, in addition, owing to avoiding when the synchronous fault of OLT or PON mouth time of occurrence, small base station cannot carry out the situation of time synchronized, therefore improve the reliability of the time synchronized between small base station.

Be described in detail the present invention program below by specific embodiment, certainly, the present invention is not limited to following examples.

Summary of the invention

The embodiment of the present invention provides a kind of method for synchronizing time and relevant device, system, lower in order to the synchronization accuracy solved in prior art between each small base station, and the problem that the reliability of time synchronized is poor.

Embodiment of the present invention technical scheme is as follows:

The embodiment of the present invention provides a kind of method for synchronizing time, comprising:

The very first time sync message that the small base station that optical network unit ONU receives its second line of a couplet sends, carries the time synchronizing signal that small base station obtains from macro base station in described very first time sync message;

In the time synchronizing signal that the very first time sync message received carries, determine that each small base station to the second line of a couplet carries out the reference synchronization source of time synchronized;

According to the reference synchronization source determined, time synchronized is carried out to each small base station of the second line of a couplet.

Therefore, in embodiment of the present invention technical scheme, when PON is the return network of small base station, after the small base station of the ONU second line of a couplet gets the time synchronizing signal of macro base station, the time synchronizing signal got is carried in very first time sync message and reports ONU, ONU chooses reference synchronization source in the time synchronizing signal received, and then carries out time synchronized according to each small base station of reference synchronization source to the second line of a couplet chosen.Therefore, when carrying out time synchronized between small base station, only need the time synchronizing signal of the reception macro base station that guarantee section small base station can be good, significantly reduce the deployment difficulty of small base station, and extend adaptation scene, even if part small base station directly can not receive the time synchronizing signal of macro base station, also time synchronized is carried out in the reference synchronization source can chosen according to ONU, without the need to from other small base stations or from GPS acquisition time synchronizing signal, effectively improve the timing tracking accuracy between small base station, in addition, owing to avoiding when the synchronous fault of OLT or PON mouth time of occurrence, small base station cannot carry out the situation of time synchronized, therefore improve the reliability of the time synchronized between small base station.

Preferably, in the time synchronizing signal that the very first time sync message received carries, determine that each small base station to the second line of a couplet carries out the reference synchronization source of time synchronized, specifically comprise:

Determine the synchronous priority that time synchronizing signal that the very first time sync message received carries is corresponding;

In the time synchronizing signal that the very first time sync message received carries, choose the time synchronizing signal that corresponding synchronous priority is the highest;

By the time synchronizing signal chosen, confirm as the reference synchronization source of each small base station of the second line of a couplet being carried out to time synchronized.

By the present embodiment scheme, according to synchronous priority synchronizing signal access time as reference synchronization source, the accuracy in the reference synchronization source chosen can be improved, thus improve the precision of time synchronized.

Preferably, in the time synchronizing signal that the very first time sync message received carries, before determining that the reference synchronization source of time synchronized is carried out to each small base station of the second line of a couplet, also comprise:

The second time synchronized message that the optical line terminal OLT that ONU receives its first line of a couplet sends, carries the time synchronizing signal that OLT obtains in described second time synchronized message;

In the time synchronizing signal that the very first time sync message received carries, determine that each small base station to the second line of a couplet carries out the reference synchronization source of time synchronized, specifically comprise:

In the time synchronizing signal that the time synchronizing signal carried at the very first time sync message received and the second time synchronized message carry, determine that each small base station to the second line of a couplet carries out the reference synchronization source of time synchronized.

By the present embodiment scheme, ONU supports the time synchronizing signal bang path of two-way not homology, time synchronizing signal that one tunnel is OLT going down, that obtain from upstream network side, another road is time synchronizing signal that small base station upwards transmits, that obtain from macro base station, wherein a road time synchronizing signal bang path break down or the time synchronizing signal that transmits is abnormal time, an other road time synchronizing signal bang path can be adopted, effectively raise the reliability of time synchronized between small base station.

Preferably, in the time synchronizing signal that the time synchronizing signal carried at the very first time sync message received and the second time synchronized message carry, determine that each small base station to the second line of a couplet carries out the reference synchronization source of time synchronized, specifically comprise:

Determine the synchronous priority that time synchronizing signal that the very first time sync message received carries is corresponding and synchronous priority corresponding to the time synchronizing signal that the second time synchronized message carries;

In the time synchronizing signal that the time synchronizing signal carried at the very first time sync message received and the second time synchronized message carry, choose the time synchronizing signal that corresponding synchronous priority is the highest;

Preferably, determine specifically to comprise the synchronous priority that time synchronizing signal that the very first time sync message received carries is corresponding:

From the preset field of the very first time sync message received, extract the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

Preferably, the synchronous priority of carrying in very first time sync message is:

After small base station gets time synchronizing signal from macro base station, determine according to the signal quality of the time synchronizing signal obtained; Or

The signal quality of time synchronizing signal that small base station prestores, that obtain from macro base station according to this small base station is determined.

In corresponding relation between the small base station prestored and synchronous priority, search the synchronous priority that the small base station of transmission very first time sync message is corresponding, and the synchronous priority that will find, confirm as the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

Preferably, the synchronous priority that small base station is corresponding is that the signal quality of the time synchronizing signal obtained from macro base station according to this small base station is in advance determined.

Preferably, determine specifically to comprise the synchronous priority that time synchronizing signal that the second time synchronized message received carries is corresponding:

From the preset field of the second time synchronized message received, extract the synchronous priority that time synchronizing signal that this second time synchronized message carries is corresponding.

Preferably, the synchronous priority of carrying in the second time synchronized message is:

After OLT gets time synchronizing signal, determine according to the signal quality of the time synchronizing signal obtained; Or

That OLT prestores, to determine according to the signal quality of time synchronizing signal obtained.

Obtain that prestore, that described OLT is corresponding synchronous priority;

The synchronous priority obtained is confirmed as the synchronous priority that time synchronizing signal that the second time synchronized message carries is corresponding.

Preferably, the synchronous priority that described OLT is corresponding determines according to the signal quality of the time synchronizing signal of OLT acquisition in advance.

The embodiment of the present invention provides a kind of optical network unit, comprising:

Very first time sync message receiving element, the very first time sync message that the small base station for receiving the described optical network unit ONU second line of a couplet sends, carries the time synchronizing signal that small base station obtains from macro base station in described very first time sync message;

Reference synchronization source determining unit, in the time synchronizing signal that carries at the very first time sync message received, determines that each small base station to the described ONU second line of a couplet carries out the reference synchronization source of time synchronized;

Time synchronized unit, for the reference synchronization source determined according to reference synchronization source determining unit, carries out time synchronized to each small base station of the described ONU second line of a couplet.

Preferably, described reference synchronization source determining unit specifically comprises:

First synchronous priority determination subelement, for determining the synchronous priority that time synchronizing signal that the very first time sync message received carries is corresponding;

Very first time synchronizing signal chooses subelement, in the time synchronizing signal that carries at the very first time sync message received, chooses the time synchronizing signal that corresponding synchronous priority is the highest;

Subelement is determined in first reference synchronization source, for very first time synchronizing signal being chosen the time synchronizing signal that subelement is chosen, confirms as the reference synchronization source of each small base station of the described ONU second line of a couplet being carried out to time synchronized.

Preferably, the described first synchronous priority determination subelement, specifically in the preset field from the very first time sync message received, extracts the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

Preferably, described first synchronous priority determination subelement, specifically in the corresponding relation between the small base station prestored and synchronous priority, search the synchronous priority that the small base station of transmission very first time sync message is corresponding, and the synchronous priority that will find, confirm as the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

Preferably, described optical network unit also comprises:

Second time synchronized message receiving element, before determining that in reference synchronization source determining unit the reference synchronization source of time synchronized is carried out to each small base station of the described ONU second line of a couplet, the second time synchronized message that the optical line terminal OLT receiving the described ONU first line of a couplet sends, carries the time synchronizing signal that OLT obtains in described second time synchronized message;

Described reference synchronization source determining unit, specifically in the time synchronizing signal that the time synchronizing signal that carries at the very first time sync message received and the second time synchronized message carry, determine that each small base station to the described ONU second line of a couplet carries out the reference synchronization source of time synchronized.

Second synchronous priority determination subelement, for determining the synchronous priority that time synchronizing signal that the very first time sync message received carries is corresponding;

3rd synchronous priority determination subelement, for determining the synchronous priority that time synchronizing signal that the second time synchronized message received carries is corresponding;

Second time synchronizing signal chooses subelement, in the time synchronizing signal that the time synchronizing signal that carries at very first time sync message and the second time synchronized message carry, chooses the time synchronizing signal that corresponding synchronous priority is the highest;

Subelement is determined in second reference synchronization source, for the second time synchronizing signal being chosen the time synchronizing signal that subelement is chosen, confirms as the reference synchronization source of each small base station of the described ONU second line of a couplet being carried out to time synchronized.

Preferably, the described second synchronous priority determination subelement, specifically in the preset field from the very first time sync message received, extracts the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

Preferably, described second synchronous priority determination subelement, specifically in the corresponding relation between the small base station prestored and synchronous priority, search the synchronous priority that the small base station of transmission very first time sync message is corresponding, and the synchronous priority that will find, confirm as the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

Preferably, the described 3rd synchronous priority determination subelement, specifically in the preset field from the second time synchronized message received, extracts the synchronous priority that time synchronizing signal that this second time synchronized message carries is corresponding.

Preferably, described 3rd synchronous priority determination subelement, specifically for obtain prestore, synchronous priority that described OLT is corresponding, the synchronous priority obtained is confirmed as the synchronous priority that time synchronizing signal that the second time synchronized message carries is corresponding.

The embodiment of the present invention provides a kind of small base station, comprising:

Time synchronizing signal acquiring unit, for acquisition time synchronizing signal from macro base station;

Time synchronized packet sending unit, the time synchronizing signal for being obtained by time synchronizing signal acquiring unit is carried in time synchronized message and sends to optical network unit ONU.

Therefore, in embodiment of the present invention technical scheme, when PON is the return network of small base station, after the small base station of the ONU second line of a couplet gets the time synchronizing signal of macro base station, the time synchronizing signal got is carried in very first time sync message and reports ONU, follow-up ONU chooses reference synchronization source in the time synchronizing signal received, and then carries out time synchronized according to each small base station of reference synchronization source to the second line of a couplet chosen.Therefore, when carrying out time synchronized between small base station, only need the time synchronizing signal of the reception macro base station that guarantee section small base station can be good, significantly reduce the deployment difficulty of small base station, and extend adaptation scene, even if part small base station directly can not receive the time synchronizing signal of macro base station, also time synchronized is carried out in the reference synchronization source can chosen according to ONU, without the need to from other small base stations or from GPS acquisition time synchronizing signal, effectively improve the timing tracking accuracy between small base station, in addition, owing to avoiding when the synchronous fault of OLT or PON mouth time of occurrence, small base station cannot carry out the situation of time synchronized, therefore improve the reliability of the time synchronized between small base station.

Preferably, described small base station also comprises:

Synchronous priority determining unit, in time synchronized packet sending unit by before sending to ONU in time synchronized message, determine the synchronous priority that time synchronizing signal that time synchronizing signal acquiring unit obtains is corresponding;

Described time synchronized packet sending unit, the synchronous priority also for synchronous priority determining unit being determined is carried in the preset field of time synchronized message and sends to ONU.

The embodiment of the present invention provides a kind of optical line terminal, comprising:

Time synchronizing signal acquiring unit, for acquisition time synchronizing signal;

Preferably, described optical line terminal also comprises:

The embodiment of the present invention provides a kind of clock synchronization system, comprises the small base station of optical network unit ONU and its second line of a couplet, wherein:

Small base station, for acquisition time synchronizing signal from macro base station, and is carried at the time synchronizing signal of acquisition in very first time sync message and sends to described ONU;

Described ONU, in the time synchronizing signal that carries at the very first time sync message received, determines the reference synchronization source of each small base station being carried out to time synchronized, according to the reference synchronization source determined, carries out time synchronized to each small base station of the second line of a couplet.

Preferably, also optical line terminal OLT is comprised;

Described OLT, for acquisition time synchronizing signal, and is carried at the time synchronizing signal of acquisition in the second time synchronized message and sends to described ONU;

Described ONU, specifically in the time synchronizing signal that the time synchronizing signal that carries at the very first time sync message received and the second time synchronized message carry, determines that each small base station to the second line of a couplet carries out the reference synchronization source of time synchronized.

Accompanying drawing explanation

Fig. 1 is in prior art, PON system configuration diagram;

Fig. 2 is in the embodiment of the present invention one, method for synchronizing time schematic flow sheet;

Fig. 3 is in the embodiment of the present invention three, the internal structure schematic diagram of ONU;

Fig. 4 is in the embodiment of the present invention three, realizes the principle schematic of time synchronized between Femto base station;

Fig. 5 is in the embodiment of the present invention four, ONU structural representation;

Fig. 6 is in the embodiment of the present invention four, small base station structural representation;

Fig. 7 is in the embodiment of the present invention four, OLT structural representation;

Fig. 8 is in the embodiment of the present invention four, clock synchronization system structural representation.

Embodiment

In order to make the object, technical solutions and advantages of the present invention clearly, below in conjunction with accompanying drawing, the present invention is described in further detail, and obviously, described embodiment is only a part of embodiment of the present invention, instead of whole embodiments.Based on the embodiment in the present invention, those of ordinary skill in the art, not making other embodiments all obtained under creative work prerequisite, belong to the scope of protection of the invention.

Embodiment one

As shown in Figure 2, be the method for synchronizing time flow chart that the embodiment of the present invention one proposes, its concrete processing procedure is as follows:

Step 21, the very first time sync message that the small base station that ONU receives its second line of a couplet sends, carries the time synchronizing signal that small base station obtains from macro base station in described very first time sync message.

The small base station mentioned in the embodiment of the present invention can be, but not limited to comprise Micro base station, Nano base station, Pico base station, Femto base station etc.

Several small base stations of the ONU second line of a couplet, part small base station wherein may be only had can to listen to the time synchronizing signal of macro base station, therefore the embodiment of the present invention one proposes, after the small base station base station of the ONU second line of a couplet gets time synchronizing signal from macro base station, the time synchronizing signal got is carried in very first time sync message and sends to ONU.

It should be noted that, ONU can choose at least one small base station needing to report time synchronizing signal in advance from each small base station of the second line of a couplet, the time synchronizing signal listening to macro base station is reported ONU by the small base station chosen, ONU only intercepts the small base station chosen, the time synchronizing signal that the small base station that reception is chosen reports.In addition, in order to avoid the small base station chosen cannot listen to the situation of the time synchronizing signal of macro base station, ONU also can intercept all small base stations of the second line of a couplet, the time synchronizing signal listened to all is reported ONU by all small base stations that can listen to the time synchronizing signal of macro base station, thus further increases the reliability of the time synchronized between small base station.

In the embodiment of the present invention one, small base station according to the report cycle preset, periodically can report the time synchronizing signal got from macro base station to ONU.

The time synchronizing signal that small base station gets from macro base station can be, but not limited to as 1588v2 time synchronizing signal, and now, above-mentioned very first time sync message is 1588v2 message.After small base station gets 1588v2 time synchronizing signal from macro base station, 1588v2 message is generated according to the 1588v2 time synchronizing signal got, and the 1588v2 message of generation is sent to ONU, ONU is by Fast Ethernet/gigabit Ethernet (Fast Ethernet/Gigabit Ethernet, FE/GE), after the 1588v2 message that interface sends to small base station, from 1588v2 message, 1588v2 time synchronizing signal is extracted by ONU chip.

ONU in the embodiment of the present invention can be, but not limited to as Fiber-To-The-Building type ONU.

Step 22, in the time synchronizing signal that the very first time sync message received carries, determines that each small base station to the second line of a couplet carries out the reference synchronization source of time synchronized.

The detailed process that ONU chooses reference synchronization source will describe in detail in embodiment two.

Step 23, according to the reference synchronization source determined, carries out time synchronized to each small base station of the second line of a couplet.

After ONU determines reference synchronization source, first utilize the reference synchronization source determined, the time of adjustment local clock, then based on the rise time time sync message of the local clock after adjustment, the time synchronized message of generation is handed down to each small base station of the second line of a couplet.If small base station can not from macro base station acquisition time synchronizing signal, then after receiving the time synchronized message that ONU issues, according to the time of the time synchronizing signal adjustment local clock carried in the time synchronized message received, thus achieve the time synchronized between each small base station.

Wherein, the time synchronized message that ONU is handed down to small base station can be 1588v2 message, small base station extracts 1588v2 time synchronizing signal after receiving the 1588v2 message that ONU issues from 1588v2 message, then according to the time of 1588v2 time synchronizing signal adjustment local clock.

If small base station can from macro base station acquisition time synchronizing signal, then can the time synchronized message received not dealt with, also the time synchronizing signal carried in the time synchronized message received and the time synchronizing signal obtained from macro base station can be compared and verify, if the signal quality verifying out the time synchronizing signal obtained from macro base station is better, then can think that the reference synchronization source that ONU chooses is abnormal, abnormal information is reported ONU by small base station, ONU is after receiving abnormal information, can again choose reference synchronization source, and rise time sync message is handed down to each small base station, thus avoiding ONU, to choose reference synchronization source abnormal, making between small base station can not the situation of precise synchronization, further increase the timing tracking accuracy between small base station.

Therefore, when carrying out time synchronized between small base station, only need the time synchronizing signal of the reception macro base station that guarantee section small base station can be good, significantly reduce the deployment difficulty of small base station, even if part small base station directly can not receive the time synchronizing signal of macro base station, also time synchronized is carried out in the reference synchronization source can chosen according to ONU, without the need to from other small base stations or from GPS acquisition time synchronizing signal, effectively improve the timing tracking accuracy between small base station, in addition, owing to avoiding when the synchronous fault of OLT or PON mouth time of occurrence, small base station cannot carry out the situation of time synchronized, therefore improve the reliability of the time synchronized between small base station.

Embodiment two

After the time synchronizing signal that the small base station that ONU receives the second line of a couplet reports, first determine the synchronous priority that time synchronizing signal that the very first time sync message received carries is corresponding, then source algorithm is selected by preset, in the time synchronizing signal that the very first time sync message received carries, choose the time synchronizing signal that corresponding synchronous priority is the highest, by the time synchronizing signal chosen, confirm as the reference synchronization source of each small base station of the second line of a couplet being carried out to time synchronized.

Wherein, the synchronous priority of time synchronizing signal can be carried in very first time sync message by small base station and report ONU, also can be determined voluntarily by ONU, be introduced respectively below to both of these case.

Situation a, the synchronous priority of time synchronizing signal is carried in very first time sync message by small base station and reports ONU.

The embodiment of the present invention two proposes, after small base station gets time synchronizing signal from macro base station, before very first time sync message is sent to ONU, can first according to the signal quality of the time synchronizing signal got, determine the synchronous priority that the time synchronizing signal that gets is corresponding, then the synchronous priority determined is carried in the preset field of very first time sync message and sends to ONU, after ONU receives the very first time sync message of small base station transmission, from the preset field of very first time sync message, extract the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

Wherein, the signal quality of time synchronizing signal can be, but not limited to the synchronous jumping figure into time synchronizing signal, the i.e. synchronous jumping figure that experiences from the process that the time server (such as 1588v2 time server) of network side arrives small base station of time synchronizing signal, the synchronous jumping figure of time synchronizing signal is more, corresponding synchronous priority is lower, synchronous jumping figure is fewer, and corresponding synchronous priority is higher.

After small base station gets time synchronizing signal from macro base station, according to the synchronous jumping figure of the time synchronizing signal got, determine the synchronous priority that the time synchronizing signal that gets is corresponding.

In addition, the signal quality of the time synchronizing signal that also can obtain from macro base station according to small base station in advance, determine the synchronous priority that this small base station is corresponding, small base station stores the synchronous priority of self correspondence, after small base station gets time synchronizing signal from macro base station, before very first time sync message is sent to ONU, the synchronous priority prestored is carried in the preset field of very first time sync message and sends to ONU, after ONU receives the very first time sync message of small base station transmission, from the preset field of very first time sync message, extract the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

If the signal quality of time synchronizing signal is the synchronous jumping figure of time synchronizing signal, during the synchronous priority that then predefined small base station is corresponding, can according to the deployment scenario of each small base station, determine the synchronous jumping figure that each small base station is required during acquisition time synchronizing signal from macro base station, then according to the synchronous jumping figure determined, the synchronous priority that each small base station is corresponding is determined.

Situation b, is determined the synchronous priority of time synchronizing signal voluntarily by ONU.

The embodiment of the present invention two proposes, pre-determine the synchronous priority that each small base station of the ONU second line of a couplet is corresponding, obtain the corresponding relation between small base station and synchronous priority, ONU stores this corresponding relation, after ONU receives the very first time sync message of each small base station transmission, in corresponding relation between the small base station stored and synchronous priority, search the synchronous priority that the small base station of transmission very first time sync message is corresponding, and the synchronous priority that will find, confirm as the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

Wherein, the signal quality of the time synchronizing signal that can obtain from macro base station according to small base station in advance, determines the synchronous priority that this small base station is corresponding.

Preferably, the embodiment of the present invention two also proposes, ONU not only can from the small base station of its second line of a couplet acquisition time synchronizing signal, acquisition time synchronizing signal in the OLT that also can join from it, after OLT gets time synchronizing signal, the time synchronizing signal got is carried in the second time synchronized message and sends to ONU.In the time synchronizing signal that ONU is follow-up can be carried at the very first time sync message received and the time synchronizing signal that the second time synchronized message carries, determine that each small base station to the second line of a couplet carries out the reference synchronization source of time synchronized.That is, ONU supports the time synchronizing signal bang path of two-way not homology, and time synchronizing signal that a road is OLT going down, that obtain from upstream network side, another road is time synchronizing signal that small base station upwards transmits, that obtain from macro base station.

Wherein, OLT can issue the cycle according to what preset, periodically issues the time synchronizing signal got from network side to ONU.This issues cycle and small base station and reports the report cycle of time synchronizing signal can be equal.

OLT can direct acquisition time synchronizing signal from the time server of network side, also can from other network equipments the time synchronizing signal of acquisition time server.

Above-mentioned time server can be, but not limited to as 1588v2 time server, and the time synchronizing signal that so OLT gets is 1588v2 time synchronizing signal, and above-mentioned second time synchronized message is 1588v2 message.After OLT gets 1588v2 time synchronizing signal, generate 1588v2 message according to the 1588v2 time synchronizing signal got, and the 1588v2 message of generation is sent to ONU, the ONU chip in ONU extracts 1588v2 time synchronizing signal from 1588v2 message.

Owing to all only having a jumping from small base station to ONU and from OLT to ONU, and time synchronizing signal is ripe high accuracy 1588v2 time synchronizing signal, therefore, it is possible to ensure the timing tracking accuracy between small base station well, meet the synchronisation requirement of small base station better.

After ONU receives very first time sync message and the second time synchronized message, first determine the synchronous priority that time synchronizing signal that the very first time sync message received carries is corresponding and synchronous priority corresponding to the time synchronizing signal that the second time synchronized message carries, then source algorithm is selected by preset, in the time synchronizing signal that the time synchronizing signal carried at the very first time sync message received and the second time synchronized message carry, choose the time synchronizing signal that corresponding synchronous priority is the highest, by the time synchronizing signal chosen, confirm as the reference synchronization source of each small base station of the second line of a couplet being carried out to time synchronized.

In situation a and situation b, describe the process of synchronous priority corresponding to time synchronizing signal that ONU determines that small base station reports, therefore mainly introduce the process of synchronous priority corresponding to time synchronizing signal that ONU determines that OLT issues below.

The synchronous priority of the time synchronizing signal that OLT issues can be carried in the second time synchronized message by OLT and be handed down to ONU, also can be determined voluntarily by ONU, be introduced respectively below to both of these case.

Situation A, the synchronous priority of time synchronizing signal is carried in the second time synchronized message by OLT and is handed down to ONU.

The embodiment of the present invention two proposes, OLT is from after network side gets time synchronizing signal, can first according to the signal quality of the time synchronizing signal got, determine the synchronous priority that the time synchronizing signal that gets is corresponding, then the synchronous priority determined is carried in the preset field of the second time synchronized message and sends to ONU, after ONU receives the second time synchronized message of OLT transmission, from the preset field of the second time synchronized message, extract the synchronous priority that time synchronizing signal that this second time synchronized message carries is corresponding.

If the signal quality of time synchronizing signal is the synchronous jumping figure of time synchronizing signal, after then OLT gets time synchronizing signal, according to the synchronous jumping figure that time synchronizing signal experiences from the process that the time server (such as 1588v2 time server) of network side arrives OLT, determine the synchronous priority that the time synchronizing signal that gets is corresponding.

In addition, also can in advance according to the signal quality of the time synchronizing signal of OLT acquisition, determine the synchronous priority that OLT is corresponding, OLT stores the synchronous priority of self correspondence, after OLT gets time synchronizing signal, the synchronous priority prestored is carried in the preset field of the second time synchronized message and sends to ONU, after ONU receives the second time synchronized message of OLT transmission, from the preset field of the second time synchronized message, extract the synchronous priority that time synchronizing signal that this second time synchronized message carries is corresponding.

If the signal quality of time synchronizing signal is the synchronous jumping figure of time synchronizing signal, during the synchronous priority that then predefined OLT is corresponding, the synchronous jumping figure that can experience from the process that the time server (such as 1588v2 time server) of network side arrives OLT according to time synchronizing signal, determines the synchronous priority that OLT is corresponding.

If OLT is acquisition time synchronizing signal from time server directly, the synchronous jumping figure of the time synchronizing signal then obtained is 1 jumping, if the time synchronizing signal of OLT acquisition time server from other network equipments, then the synchronous jumping figure of the time synchronizing signal obtained is greater than 1 jumping.

The embodiment of the present invention two proposes, pre-determine the synchronous priority that OLT is corresponding, the synchronous priority that ONU storage is determined, after ONU receives the second time synchronized message of OLT transmission, obtain the synchronous priority that this OLT of prestoring is corresponding, then the synchronous priority obtained is confirmed as the synchronous priority that time synchronizing signal that the second time synchronized message carries is corresponding.

Wherein, in advance according to the signal quality of the time synchronizing signal of OLT acquisition, the synchronous priority that OLT is corresponding can be determined.

The embodiment of the present invention two proposes, in the time synchronizing signal that the time synchronizing signal reported at small base station and OLT issue, if the time synchronizing signal that the synchronous priority of correspondence is the highest only has one, then this time synchronizing signal directly can be chosen for reference synchronization source by ONU, if the synchronous priority that at least two time synchronizing signals are corresponding is the highest, then ONU can choose a time synchronizing signal as reference synchronization source in each time synchronizing signal that the synchronous priority of correspondence is the highest, wherein, ONU can in each time synchronizing signal that the synchronous priority of correspondence is the highest, random selecting time synchronizing signal is as reference synchronization source.

Therefore, ONU supports the time synchronizing signal bang path of two-way not homology, time synchronizing signal that one tunnel is OLT going down, that obtain from upstream network side, another road is time synchronizing signal that small base station upwards transmits, that obtain from macro base station, ONU, according to selecting source algorithm, chooses reference synchronization source from each time synchronizing signal received.Preferably, ONU can determine whether enable and selects algorithm picks reference synchronization source, source and selects the time synchronizing signal source category comprised in the algorithm of source according to actual conditions, time signal source comprise time synchronizing signal that small base station reports and the time synchronizing signal that OLT issues.Wherein a road time synchronizing signal bang path break down or the time synchronizing signal that transmits is abnormal time, an other road time synchronizing signal bang path can be adopted, effectively raise the reliability of time synchronized between small base station.

In the normal mode of operation, ONU enables and selects source algorithm, and time synchronizing signal source comprises time synchronizing signal that small base station reports and the time synchronizing signal that OLT issues.When the bang path that the time synchronizing signal exception that ONU chip detection sends to OLT or OLT issue time synchronizing signal breaks down, ONU is by selecting algorithm picks reference synchronization source, source during in use, no longer select the time synchronizing signal that OLT issues.When the time synchronizing signal exception that ONU chip detection sends to small base station or small base station report the bang path of time synchronizing signal to break down, stop using and select source algorithm, the time synchronizing signal directly using OLT to issue is as reference synchronization source.

Embodiment three

The embodiment of the present invention three proposes, and can increase time synchronized module in ONU, realizes the method for synchronizing time of the embodiment of the present invention one and the embodiment of the present invention two proposition.The internal structure of ONU as shown in Figure 3.

If above-mentioned small base station is Femto base station, then based on the internal structure of the ONU shown in Fig. 3, realize the principle of time synchronized between Femto base station as shown in Figure 4, detailed process is as follows:

FE/GE interface in ONU obtains 1588v2 message from the Femto base station of the second line of a couplet, 1588v2 message is transferred to the process of ONU chip, ONU chip extracts 1588v2 time synchronizing signal from 1588v2 message, then the 1588v2 time synchronizing signal extracted is sent to time synchronized module.Time synchronized module, by selecting source algorithm, optimizes a 1588v2 time synchronizing signal as reference synchronization source, and reference synchronization source is supplied to ONU chip and CPU in each 1588v2 time synchronizing signal that Femto base station sends.

Reception optical module in ONU also can obtain 1588v2 message from the OLT of the first line of a couplet receives, receive optical module and 1588v2 message is transferred to the process of ONU chip, ONU chip extracts 1588v2 time synchronizing signal from 1588v2 message, then the 1588v2 time synchronizing signal extracted is sent to time synchronized module.Time synchronized module, by selecting source algorithm, optimizes a 1588v2 time synchronizing signal as reference synchronization source, and reference synchronization source is supplied to ONU chip and CPU in each 1588v2 time synchronizing signal that Femto base station and OLT send.

ONU chip utilizes the synchronous local clock in reference synchronization source optimized, and generate 1588v2 message based on the time of local clock, the 1588v2 message going down of generation is given all Femto base stations of this ONU second line of a couplet, time synchronized is carried out according to 1588v2 message in each Femto base station.

The embodiment of the present invention three proposes, and time synchronized module can adopt independently chip to realize, and cooperated with ONU chip above-mentioned flow process, and in addition, time synchronized module also can be integrated in ONU chip.

Time synchronization process and the said process of other small base stations (such as Nano base station or Micro base station) are similar, repeat no longer one by one here.

Embodiment four

Corresponding with the method for synchronizing time that the embodiment of the present invention one proposes, the embodiment of the present invention four proposes a kind of ONU, and its structure as shown in Figure 5, comprising:

Very first time sync message receiving element 51, the very first time sync message that the small base station for receiving the described ONU second line of a couplet sends, carries the time synchronizing signal that small base station obtains from macro base station in described very first time sync message;

Reference synchronization source determining unit 52, in the time synchronizing signal that carries at the very first time sync message received, determines that each small base station to the described ONU second line of a couplet carries out the reference synchronization source of time synchronized;

Time synchronized unit 53, for the reference synchronization source determined according to reference synchronization source determining unit 52, carries out time synchronized to each small base station of the described ONU second line of a couplet.

Preferably, described reference synchronization source determining unit 52 specifically comprises:

Preferably, described optical network unit also comprises:

Described reference synchronization source determining unit 52, specifically in the time synchronizing signal that the time synchronizing signal that carries at the very first time sync message received and the second time synchronized message carry, determine that each small base station to the described ONU second line of a couplet carries out the reference synchronization source of time synchronized.

The embodiment of the present invention four also proposes a kind of small base station, and its structure as shown in Figure 6, comprising:

Time synchronizing signal acquiring unit 61, for acquisition time synchronizing signal from macro base station;

Time synchronized packet sending unit 62, the time synchronizing signal for being obtained by time synchronizing signal acquiring unit 61 is carried in time synchronized message and sends to ONU.

Preferably, described small base station also comprises:

Synchronous priority determining unit, in time synchronized packet sending unit 62 by before sending to ONU in time synchronized message, determine the synchronous priority that time synchronizing signal that time synchronizing signal acquiring unit 61 obtains is corresponding;

Described time synchronized packet sending unit 62, the synchronous priority also for synchronous priority determining unit being determined is carried in the preset field of time synchronized message and sends to ONU.

The embodiment of the present invention four also proposes a kind of OLT, and its structure as shown in Figure 7, comprising:

Time synchronizing signal acquiring unit 71, for acquisition time synchronizing signal;

Time synchronized packet sending unit 72, the time synchronizing signal for being obtained by time synchronizing signal acquiring unit 71 is carried in time synchronized message and sends to ONU.

Preferably, described OLT also comprises:

Synchronous priority determining unit, in time synchronized packet sending unit 72 by before sending to ONU in time synchronized message, determine the synchronous priority that time synchronizing signal that time synchronizing signal acquiring unit 71 obtains is corresponding;

Described time synchronized packet sending unit 72, the synchronous priority also for synchronous priority determining unit being determined is carried in the preset field of time synchronized message and sends to ONU.

The embodiment of the present invention provides a kind of clock synchronization system, and its structure as shown in Figure 8, comprises the small base station 82 of ONU81 and its second line of a couplet, wherein:

Small base station 82, for acquisition time synchronizing signal from macro base station, and is carried at the time synchronizing signal of acquisition in very first time sync message and sends to described ONU;

Described ONU81, in the time synchronizing signal that carries at the very first time sync message received, determines the reference synchronization source of each small base station being carried out to time synchronized, according to the reference synchronization source determined, carries out time synchronized to each small base station of the second line of a couplet.

Preferably, also OLT83 is comprised;

Those skilled in the art should understand, embodiments of the invention can be provided as method, system or computer program.The present invention can adopt in one or more form wherein including the upper computer program implemented of computer-usable storage medium (including but not limited to magnetic disc store, CD-ROM, optical memory etc.) of computer usable program code.

The present invention describes with reference to according to the flow chart of the method for the embodiment of the present invention, equipment (system) and computer program and/or block diagram.Should understand can by the combination of the flow process in each flow process in computer program instructions realization flow figure and/or block diagram and/or square frame and flow chart and/or block diagram and/or square frame.These computer program instructions can being provided to the processor of all-purpose computer, special-purpose computer, Embedded Processor or other programmable data processing device to produce a machine, making the instruction performed by the processor of computer or other programmable data processing device produce device for realizing the function of specifying in flow chart flow process or multiple flow process and/or block diagram square frame or multiple square frame.

These computer program instructions also can be stored in can in the computer-readable memory that works in a specific way of vectoring computer or other programmable data processing device, the instruction making to be stored in this computer-readable memory produces the manufacture comprising command device, and this command device realizes the function of specifying in flow chart flow process or multiple flow process and/or block diagram square frame or multiple square frame.

These computer program instructions also can be loaded in computer or other programmable data processing device, make on computer or other programmable devices, to perform sequence of operations step to produce computer implemented process, thus the instruction performed on computer or other programmable devices is provided for the step realizing the function of specifying in flow chart flow process or multiple flow process and/or block diagram square frame or multiple square frame.

According to defining herein, computer-readable medium does not comprise the computer readable media (transitory media) of non-standing, as data-signal and the carrier wave of modulation.

Although describe the preferred embodiments of the present invention, those skilled in the art once obtain the basic creative concept of cicada, then can make other change and amendment to these embodiments.So claims are intended to be interpreted as comprising preferred embodiment and falling into all changes and the amendment of the scope of the invention.

Obviously, those skilled in the art can carry out various change and modification to the present invention and not depart from the spirit and scope of the present invention.Like this, if these amendments of the present invention and modification belong within the scope of the claims in the present invention and equivalent technologies thereof, then the present invention is also intended to comprise these change and modification.

Claims

1. a method for synchronizing time, is characterized in that, comprising:

2. the method for claim 1, is characterized in that, in the time synchronizing signal that the very first time sync message received carries, determines that each small base station to the second line of a couplet carries out the reference synchronization source of time synchronized, specifically comprises:

3. the method for claim 1, is characterized in that, in the time synchronizing signal that the very first time sync message received carries, before determining to carry out the reference synchronization source of time synchronized to each small base station of the second line of a couplet, also comprises:

4. method as claimed in claim 3, it is characterized in that, in the time synchronizing signal that the time synchronizing signal carried at the very first time sync message received and the second time synchronized message carry, determine that each small base station to the second line of a couplet carries out the reference synchronization source of time synchronized, specifically comprise:

5. the method as described in claim 2 or 4, is characterized in that, determines specifically to comprise the synchronous priority that time synchronizing signal that the very first time sync message received carries is corresponding:

6. method as claimed in claim 5, it is characterized in that, the synchronous priority of carrying in very first time sync message is:

7. the method as described in claim 2 or 4, is characterized in that, determines specifically to comprise the synchronous priority that time synchronizing signal that the very first time sync message received carries is corresponding:

8. method as claimed in claim 7, is characterized in that, the synchronous priority that small base station is corresponding is that the signal quality of the time synchronizing signal obtained from macro base station according to this small base station is in advance determined.

9. method as claimed in claim 4, is characterized in that, determines specifically to comprise the synchronous priority that time synchronizing signal that the second time synchronized message received carries is corresponding:

10. method as claimed in claim 9, it is characterized in that, the synchronous priority of carrying in the second time synchronized message is:

11. methods as claimed in claim 4, is characterized in that, determine specifically to comprise the synchronous priority that time synchronizing signal that the second time synchronized message received carries is corresponding:

Obtain that prestore, that described OLT is corresponding synchronous priority;

12. methods as claimed in claim 11, is characterized in that, the synchronous priority that described OLT is corresponding determines according to the signal quality of the time synchronizing signal of OLT acquisition in advance.

13. 1 kinds of optical network units, is characterized in that, comprising:

14. optical network units as claimed in claim 13, is characterized in that, described reference synchronization source determining unit specifically comprises:

15. optical network units as claimed in claim 14, it is characterized in that, described first synchronous priority determination subelement, specifically in the preset field from the very first time sync message received, extracts the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

16. optical network units as claimed in claim 14, it is characterized in that, described first synchronous priority determination subelement, specifically in the corresponding relation between the small base station prestored and synchronous priority, search the synchronous priority that the small base station of transmission very first time sync message is corresponding, and the synchronous priority that will find, confirm as the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

17. optical network units as claimed in claim 13, is characterized in that, also comprise:

18. optical network units as claimed in claim 17, is characterized in that, described reference synchronization source determining unit specifically comprises:

19. optical network units as claimed in claim 18, it is characterized in that, described second synchronous priority determination subelement, specifically in the preset field from the very first time sync message received, extracts the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

20. optical network units as claimed in claim 18, it is characterized in that, described second synchronous priority determination subelement, specifically in the corresponding relation between the small base station prestored and synchronous priority, search the synchronous priority that the small base station of transmission very first time sync message is corresponding, and the synchronous priority that will find, confirm as the synchronous priority that time synchronizing signal that this very first time sync message carries is corresponding.

21. optical network units as claimed in claim 18, it is characterized in that, described 3rd synchronous priority determination subelement, specifically in the preset field from the second time synchronized message received, extracts the synchronous priority that time synchronizing signal that this second time synchronized message carries is corresponding.

22. optical network units as claimed in claim 18, it is characterized in that, described 3rd synchronous priority determination subelement, specifically for obtain prestore, synchronous priority that described OLT is corresponding, the synchronous priority obtained is confirmed as the synchronous priority that time synchronizing signal that the second time synchronized message carries is corresponding.

23. 1 kinds of small base stations, is characterized in that, comprising:

24. small base stations as claimed in claim 23, is characterized in that, also comprise:

25. 1 kinds of optical line terminals, is characterized in that, comprising:

26. optical line terminals as claimed in claim 25, is characterized in that, also comprise:

27. 1 kinds of clock synchronization systems, is characterized in that, comprise the small base station of optical network unit ONU and its second line of a couplet, wherein:

28. systems as claimed in claim 27, is characterized in that, also comprise optical line terminal OLT;