CN102136901A

CN102136901A - Time synchronization method, device and system

Info

Publication number: CN102136901A
Application number: CN2010105197130A
Authority: CN
Inventors: 吴安妮; 潘众
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2010-10-26
Filing date: 2010-10-26
Publication date: 2011-07-27

Abstract

The embodiment of the invention discloses a time synchronization method, a time synchronization device and a time synchronization system, relating to the field of communication. In order to provide an xDSL (x Digital Subscriber Line) technology to realize high-precision time synchronization and meet the requirement of mobile service; the embodiment of the invention provides the following technical scheme: obtaining the first receiving time information of a local DTU deframer for receiving the check bit of a first check data sending unit when the upstream time delay and the downstream time delay between a PMD (physical medium dependent sublayer) of a receiving end and a PMD of a sending end are the same; obtaining the second sending time information of a local DTU framer for sending the check bit of a second check data sending unit; obtaining the first sending time information of a DTU deframer of the sending end for sending the check bit of a first check data sending unit and the second receiving time information for receiving the check bit of the second check data sending unit; and adjusting time according to the first sending time information, the second sending time information, the first receiving time information and the second receiving time information so as to synchronize the time of a local clock and a clock at the sensing end.

Description

Method for synchronizing time, Apparatus and system

Technical field

The present invention relates to the communications field, relate in particular to a kind of method for synchronizing time, Apparatus and system.

Background technology

Along with the development of wireless technology, 3G (Third Generation) Moblie and LTE's (Long Term Evolution, Long Term Evolution) is commercial gradually, the mobile base station gradually to high density lay, high bandwidth, direction develops cheaply.Thereby, require broadband access technology is applied in the mobile bearer network.To reduce the cost of mobile bearer network.Meanwhile, broadband access technology need provide the high accuracy clock transmission, and promptly high-precision Frequency Synchronization and high precision time synchronization are to satisfy the needs of mobile service.

XDSL (Digital subscriber line, digital subscriber system) technology is to lay access technology the most widely at present, applies it in the mobile bearer network, can be used as a solution of mobile bearer network cost degradation.At present, the xDSL technology provides NTR (Network Time Reference, network clocking reference) scheme, can satisfy the requirement of mobile service to the high accuracy Frequency Synchronization.

Aspect time synchronized, because existing xDSL system, the up-downgoing time delay of its physical layer is unequal (promptly not having symmetry), can not satisfy the requirement of PTP (Precision Time Protocol, time synchronization protocol) scheme to physical layer up-downgoing time delay symmetry.Therefore, existing xDSL system can't adopt PTP to realize high precision time synchronization.In addition, the existing Ethernet system utilizes synchronization pulse to carry out time synchronized, but to the symbol be unit continuously the passband transmission system of transmission (as DMT (Discrete Multi Tone, Discrete multi-tone) system, OFDM (Orthogonal Frequency Division Multiplexing, OFDM) system etc.), there is not obvious limit between adjacent-symbol, therefore, the very difficult mode of using the Ethernet connecting system to be adopted of existing xDSL system realizes high precision time synchronization.

In realizing process of the present invention, the inventor finds that there are the following problems at least in the prior art: existing xDSL system can't provide high precision time synchronization, to satisfy the needs of mobile service.

Summary of the invention

Embodiments of the invention provide a kind of method for synchronizing time, Apparatus and system, can provide to realize the synchronous xDSL technology of split-second precision, to satisfy the needs of mobile service.

For achieving the above object, embodiments of the invention adopt following technical scheme:

A kind of method for synchronizing time comprises:

When the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal equates, when receiving the first detection data transmission unit of described transmitting terminal transmission, obtain first receiving time information, the DTU deframer that described first receiving time information is described receiving terminal receives described first the temporal information when detecting the detection bit of data transmission unit;

Sending second to described transmitting terminal when detecting data transmission unit, obtain second transmission time information, the DTU framer that described second transmission time information is described receiving terminal sends described second the temporal information when detecting the detection bit of data transmission unit;

Receive first transmission time information and second receiving time information that described transmitting terminal sends, the DTU framer that described first transmission time information is described transmitting terminal sends described first the temporal information when detecting the detection bit of data transmission unit, and the DTU deframer that described second receiving time information is described transmitting terminal receives described second the temporal information when detecting the detection bit of data transmission unit;

According to described first transmission time information, described first receiving time information, described second transmission time information and described second receiving time information time of carrying out is adjusted, and makes the clock of described receiving terminal and the clock of described transmitting terminal reach time synchronized.

A kind of time synchronism apparatus comprises:

Data transmission unit parse for frame module is used for the first detection data transmission unit that receiving end/sending end sends; Perhaps, receive first transmission time information and second receiving time information that described transmitting terminal sends, the DTU framer that described first transmission time information is described transmitting terminal sends described first the temporal information when detecting the detection bit of data transmission unit, and the DTU deframer that described second receiving time information is described transmitting terminal receives described second the temporal information when detecting the detection bit of data transmission unit;

Data transmission unit becomes frame module, is used to generate second and detects data transmission unit, and send the described second detection data transmission unit to described transmitting terminal;

The clock acquisition module is used to obtain first receiving time information, and described first receiving time information is that described data transmission unit parse for frame module receives described first the temporal information when detecting the detection bit of data transmission unit; Perhaps, obtain second transmission time information, described second transmission time information is that described data transmission unit becomes frame module to send described second the temporal information when detecting the detection bit of data transmission unit;

Correct module, be used for when the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal equates, first receiving time information and second transmission time information that obtain according to described clock acquisition module, first transmission time information that described data transmission unit parse for frame module is obtained and second receiving time information time of carrying out is adjusted, and makes the clock of described receiving terminal and the clock of described transmitting terminal reach time synchronized.

A kind of time synchronism apparatus comprises:

Data transmission unit becomes frame module, and be used for sending first and detect data transmission unit to receiving terminal, and first transmission time information and second receiving time information that obtain to described receiving terminal tranmitting data register acquisition module;

Data transmission unit parse for frame module is used to receive the second detection data transmission unit that described receiving terminal sends;

The clock acquisition module is used to obtain first transmission time information, and described first transmission time information is that described data transmission unit becomes frame module to send described first the temporal information when detecting the detection bit of data transmission unit; Perhaps, obtain second receiving time information, described second receiving time information is that described data transmission unit parse for frame module receives described second the temporal information when detecting the detection bit of data transmission unit.

A kind of clock synchronization system comprises transmitting terminal and receiving terminal;

Described transmitting terminal, be used for when the up-downgoing time delay between the pmd layer of the pmd layer of described transmitting terminal and described receiving terminal equates, when sending the first detection data transmission unit to described receiving terminal, obtain first transmission time information, the DTU framer that described first transmission time information is described transmitting terminal sends described first the temporal information when detecting the detection bit of data transmission unit; When receiving the second detection data transmission unit of described receiving terminal transmission, obtain second receiving time information, the DTU deframer that described second receiving time information is described transmitting terminal receives described second the temporal information when detecting the detection bit of data transmission unit; Send described first transmission time information and described second receiving time information to described receiving terminal;

Described receiving terminal, be used for when receiving the first detection data transmission unit of described transmitting terminal transmission, obtain first receiving time information, the DTU deframer that described first receiving time information is described receiving terminal receives described first the temporal information when detecting the detection bit of data transmission unit; Sending second to described transmitting terminal when detecting data transmission unit, obtain second transmission time information, the DTU framer that described second transmission time information is described receiving terminal sends described second the temporal information when detecting the detection bit of data transmission unit; Receive first transmission time information and second receiving time information that described transmitting terminal sends; According to described first transmission time information, described first receiving time information, described second transmission time information and described second receiving time information time of carrying out is adjusted, and makes the clock of described receiving terminal and the clock of described transmitting terminal reach time synchronized.

The method for synchronizing time that the embodiment of the invention provides, Apparatus and system, by when the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal equates, transmitting terminal sends first first transmission time information that obtains when detecting the detection bit of data transmission unit with DTUframer and is notified to receiving terminal, and the DTU deframer of receiving terminal first obtains first receiving time information when detecting the detection bit of data transmission unit receiving this; And, receiving terminal obtains DTU framer and sends second second transmission time information when detecting the detection bit of data transmission unit, and transmitting terminal receives second second receiving time information that obtains when detecting the detection bit of data transmission unit with DTU deframer and is notified to receiving terminal; Then, receiving terminal is according to first transmission time information, and first receiving time information, second transmission time information and second receiving time information time of carrying out is adjusted, and makes the clock of receiving terminal and the clock of transmitting terminal reach time synchronized.Therefore, can be in the xDSL system to realize that with a kind of simple time synchronized mechanism the clock of the clock of transmitting terminal and receiving terminal reaches precise time synchronous, satisfy the needs of mobile service to timing tracking accuracy.Thereby, can in the cost that reduces mobile bearer network, realize that split-second precision is synchronous.

Description of drawings

In order to be illustrated more clearly in the technical scheme of the embodiment of the invention, the accompanying drawing of required use is done to introduce simply in will describing embodiment below.Apparently, the accompanying drawing in describing below only is some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain other accompanying drawing according to these accompanying drawings.

A kind of method for synchronizing time schematic flow sheet that Fig. 1 provides for the embodiment of the invention;

The another kind of method for synchronizing time schematic flow sheet that Fig. 2 provides for the embodiment of the invention;

Fig. 3 is the time delay schematic diagram between the pmd layer of the pmd layer of embodiment of the invention transmitting terminal and receiving terminal;

Fig. 4 is embodiment of the invention PMS-TC layer function model structure figure;

Fig. 5 is embodiment of the invention PMS-TC layer function model structure figure;

Fig. 6 is the framing format schematic diagram of embodiment of the invention data transmission unit;

Fig. 7 is the framing format schematic diagram of embodiment of the invention data transmission unit;

Fig. 8 constitutes schematic diagram for a kind of time synchronism apparatus that the embodiment of the invention provides;

Fig. 9 constitutes schematic diagram for the another kind of time synchronism apparatus that the embodiment of the invention provides;

Figure 10 constitutes schematic diagram for a kind of clock synchronization system that the embodiment of the invention provides.

Embodiment

Below in conjunction with the accompanying drawing in the embodiment of the invention, the technical scheme in the embodiment of the invention is clearly and completely described.Obviously, described embodiment only is the present invention's part embodiment, rather than whole embodiment.Based on the embodiment among the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that is obtained under the creative work prerequisite.

Realize that in order to provide the synchronous xDSL technology of split-second precision satisfies the needs of mobile service, the embodiment of the invention provides a kind of method for synchronizing time, as shown in Figure 1, comprising:

101, as the PMD of receiving terminal (Physical Media Dependent, physical medium is relevant) when up-downgoing time delay between the pmd layer of layer and transmitting terminal equates, receiving terminal is when the first detection data transmission unit that receiving end/sending end sent, obtain first receiving time information, the DTU deframer that described first receiving time information is a receiving terminal receives described first the temporal information when detecting the detection bit of data transmission unit;

For example, can be before the time synchronized between the clock of clock that carries out transmitting terminal and receiving terminal operation, uplink time delay and descending time delay between the pmd layer that obtains receiving terminal and the pmd layer of transmitting terminal are for example passed through modes such as measurement, quantification.When according to uplink time delay and descending time delay between the pmd layer of the pmd layer of the receiving terminal that is obtained and transmitting terminal, when determining that up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal is unequal, can adjust by the mode of compensation, make that the up-downgoing time delay between the pmd layer of pmd layer and transmitting terminal of receiving terminal equates.

Receiving terminal can determine that the specified bit data among this DTU are the data that are used for carrying out time synchronized according to predetermined rule (as the sequence number of DTU or the sign among the DTU etc.) when receiving DTU (Data Transfer Unit, data transmission unit).At this, this DTU is called first detects data transmission unit, these specified bit data are called the detection bit, for example first of the first detection data transmission unit compares top grade.When the DTUdeframer of receiving terminal in this locality receives the detection bit of the first detection data transmission unit, obtain the temporal information of local clock, i.e. first receiving time information, for example time stamp T s1.

102, receiving terminal is when sending the second detection data transmission unit to described transmitting terminal, obtain second transmission time information, the DTU framer that described second transmission time information is a receiving terminal sends described second the temporal information when detecting the detection bit of data transmission unit;

For example, receiving terminal can determine that a certain DTU that issues transmitting terminal is used for carrying out time synchronized according to preset rule.At this, this DTU is called second detects data transmission unit.When receiving terminal sends the specified bit of the second detection data transmission unit at the DTU of this locality framer, obtain the temporal information of local clock, i.e. second transmission time information, for example time stamp T s2.At this, this specified bit is called the detection bit.

In addition, the detection bit that the second detection bit and first that detects data transmission unit detects data transmission unit can detect on the position identical in the data transmission unit and the second detection data transmission unit first, as all being first bit that the first detection data transmission unit and second detects data transmission unit.Certainly, the detection bit of the detection bit of the second detection data transmission unit and the first detection data transmission unit also can detect on the positions different in the data transmission unit and the second detection data transmission unit first respectively.

103, receiving terminal receives first transmission time information and second receiving time information that described transmitting terminal sends, the DTU framer that described first transmission time information is described transmitting terminal sends described first the temporal information when detecting the detection bit of data transmission unit, and the DTU deframer that described second receiving time information is described transmitting terminal receives described second the temporal information when detecting the detection bit of data transmission unit;

For example, receiving terminal can send first the temporal information when detecting the detection Bit data of DTU according to the DTU framer that predetermined rule (as the DTU sequence number of the DTU that receives or the sign among the DTU etc.) determine whether to comprise among the DTU transmitting terminal, i.e. first transmission time information, for example time stamp T m1.And, receiving terminal can receive second the temporal information when detecting the detection bit of data transmission unit according to the DTU deframer that predetermined rule (as the sign among the DTU of the sequence number of the DTU that receives or reception etc.) determines to comprise among a certain DTU transmitting terminal, i.e. second receiving time information, for example time stamp T m2.Wherein, the described first information carrying data transmission unit or the second information-bearing data transmission unit are by the first time delay channel transfer.At this, the DTU that will comprise first transmission time information is called first information carrying data transmission unit, and the DTU that will comprise second receiving time information is called the second information-bearing data transmission unit.Receiving terminal obtains first transmission time information from the specified bit of first information carrying data transmission unit, obtain second receiving time information from the specified bit of the second information-bearing data transmission unit.

Perhaps, receiving terminal also can determine whether comprise first transmission time information and second receiving time information among the DTU according to predetermined rule (as the DTU sequence number of the DTU that receives or the sign among the DTU etc.), for example time stamp T m1 and time stamp T m.Wherein, described the 3rd information-bearing data transmission unit is by the first time delay channel transfer.At this, this DTU is called the 3rd information-bearing data transmission unit, receiving terminal obtains first transmission time information and second receiving time information from the specified bit of the 3rd information-bearing data transmission unit.

Perhaps, receiving terminal also can be from the administrative messag that transmitting terminal sent, and the DTU framer that obtains transmitting terminal sends first the temporal information (first transmission time information) when detecting the detection bit of data transmission unit, for example time stamp T m1.Then, the administrative messag of sending after the receiving terminal receiving end/sending end, the DTU deframer that therefrom obtains transmitting terminal receive second the temporal information (second receiving time information) when detecting the detection bit of data transmission unit, for example time stamp T m2.At this, the administrative messag that will comprise first transmission time information is called first administrative messag, and the administrative messag that will comprise second receiving time information is called second administrative messag.

Perhaps, the administrative messag that receiving terminal also can receiving end/sending end be sent, the DTU framer that therefrom obtains transmitting terminal send first when detecting the detection bit of data transmission unit temporal information (first transmission time information) and the DTU deframer of transmitting terminal receive the second detection data transmission unit the detection bit time temporal information (second receiving time information), at this, this administrative messag is called the 3rd administrative messag.

104, receiving terminal is according to described first transmission time information, and described first receiving time information, described second transmission time information, described second receiving time information time of carrying out is adjusted, and makes the clock of receiving terminal and the clock of transmitting terminal reach time synchronized.

For example, the up-downgoing that interleaver (interleaver) on the passage between transmitting terminal and the receiving terminal the is produced time delay that interweaves equates (when interleaver goes to enable, think that the up-downgoing time delay that interweaves equates) time, the first transmission time information Tm1 can obtained, the first receiving time information Ts1, behind the second transmission time information Ts2 and the second receiving time information Tm2, according to formula Offset=(Ts1+Ts2-Tm1-Tm2)/2, obtain the time offset Offset between the clock of the clock of receiving terminal and transmitting terminal.When interleaver goes to enable, think that the up-downgoing time delay that interweaves equates.Under the up-downgoing that interleaver produced interweaves the unequal situation of time delay, the up-downgoing of the obtaining interleaver delay inequality Delay that interweaves _IlvReceiving terminal is obtaining the first transmission time information Tm1, and the first receiving time information Ts1 is behind the second transmission time information Ts2 and the second receiving time information Tm2, according to formula Offset=(Ts1+Ts2-Tm1-Tm2-Delay _Ilv)/2 obtain the time offset Offset between the clock of the clock of receiving terminal and transmitting terminal.After obtaining time offset Offset, the time according to time offset Offset adjusts local clock, make the clock of receiving terminal and the clock of transmitting terminal reach time synchronized.In general, master clock is positioned at transmitting terminal, is positioned at receiving terminal from clock.The clock of receiving terminal and the clock of transmitting terminal reach time synchronized and promptly mean between clock and master clock and reach time synchronized.

In addition, also can be before carrying out time synchronized, and, obtain the up-downgoing delay inequality Delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal _PmdAfterwards, the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal is not adjusted, and obtaining the first transmission time information Tm1 at receiving terminal, the first receiving time information Ts1, behind the second transmission time information Ts2 and the second receiving time information Tm2, according to formula Offset=(Ts1+Ts2-Tm1-Tm2-Delay _Ilv-Delay _Pmd)/2 obtain the time offset Offset between the clock of the clock of receiving terminal and transmitting terminal.And, the time according to this time offset Offset adjusts local clock, make the clock of receiving terminal and the clock of transmitting terminal reach time synchronized.

The method for synchronizing time that present embodiment provides, by when the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal equates, receiving terminal obtains first receiving time information when the first detection data transmission unit that DTU deframer receiving end/sending end sends, receiving terminal obtains second transmission time information when sending the detection bit of the second detection data transmission unit to transmitting terminal, and obtains first transmission time information and second receiving time information that transmitting terminal sends; Then, according to first transmission time information, first receiving time information, second transmission time information, second receiving time information carries out the time synchronized adjustment.Therefore, can be in the xDSL system to realize reaching precise time between the clock of the clock of transmitting terminal and receiving terminal with a kind of simple time synchronized mechanism synchronous, satisfy the needs of mobile service to timing tracking accuracy.Thereby, can in the cost that reduces mobile bearer network, realize that split-second precision is synchronous.

In addition, when transmitting terminal and receiving terminal have a plurality of time delay passage, can only on a time delay passage between transmitting terminal and the receiving terminal, above-mentioned DTU framer and DTUdeframer be set, carry out the time synchronized between the clock of the clock of transmitting terminal and receiving terminal.Thereby, realize that with a spot of device split-second precision is synchronous.

With said method accordingly, the embodiment of the invention also provides a kind of method for synchronizing time, as shown in Figure 2, comprising:

201, when the up-downgoing time delay between the pmd layer of the pmd layer of transmitting terminal and receiving terminal equates, transmitting terminal is when sending the first detection data transmission unit to receiving terminal, obtain first transmission time information, the DTU framer that described first transmission time information is a transmitting terminal sends described first the temporal information when detecting the detection bit of data transmission unit;

For example, can be before the time synchronized between the clock of clock that carries out transmitting terminal and receiving terminal operation, the up-downgoing time delay between the pmd layer that obtains transmitting terminal and the pmd layer of receiving terminal is for example passed through modes such as measurement, quantification.According to the up-downgoing time delay between the pmd layer of transmitting terminal that is obtained and receiving terminal, when the up-downgoing time delay between the pmd layer of determining transmitting terminal and receiving terminal is unequal, can adjust by the mode of compensation, make that the up-downgoing time delay between the pmd layer of pmd layer and receiving terminal of transmitting terminal equates.

Transmitting terminal generates corresponding DTU with data and the administrative messag that TPS-TC (Transport Protocol Specific-Transmission Convergence, transportation protocol is specific-Transmission Convergence) layer sends.Transmitting terminal can be determined the specified bit among a certain DTU according to preset rule when receiving terminal sends the DTU that generates, and it is used for carrying out time synchronized.At this, this DTU is called first detects data transmission unit, this specified bit is called the detection bit, for example first compares top grade.When transmitting terminal sends the detection bit of this first detection data transmission unit at the DTU of this locality framer, obtain the temporal information of local clock, i.e. first transmission time information, for example time stamp T m1.

202, transmitting terminal is when receiving the second detection data transmission unit that is sent by receiving terminal, obtain second receiving time information, the DTU deframer that described second receiving time information is a transmitting terminal receives described second the temporal information when detecting the detection bit of data transmission unit;

For example, transmitting terminal can determine that the specified bit among this DTU is the data that are used for carrying out time synchronized according to predetermined rule (as the sequence number of DTU etc.) when receiving DTU, at this this DTU is called second and detects data transmission unit.When transmitting terminal receives the detection bit of this second detection data transmission unit at the DTU of this locality deframer, obtain the temporal information of local clock, i.e. second receiving time information, for example time stamp T m1.

203, transmitting terminal sends described first transmission time information and described second receiving time information to described receiving terminal, so that described receiving terminal carries out the time synchronized adjustment according to described first transmission time information and described second receiving time information.

For example, transmitting terminal can be determined a certain DTU according to preset rule, first transmission time information is added in this DTU, and sends this DTU to receiving terminal.And this DTU is first information carrying data transmission unit.Then, transmitting terminal can be determined a certain DTU according to preset rule, second receiving time information is added in this DTU, and sends this DTU to receiving terminal.And this DTU is the second information-bearing data transmission unit.Wherein, the described first information carrying data transmission unit or the second information-bearing data transmission unit are by the first time delay channel transfer.For example, transmitting terminal can add first transmission time information and send to receiving terminal in the DTU of regulation sequence number.Then, transmitting terminal adds second receiving time information and sends to receiving terminal in the DTU of regulation sequence number.Perhaps, transmitting terminal also can be after sending the first detection data transmission unit, select a DTU to carry data transmission unit as the first information, add first transmission time information and sign in this first information carrying data transmission unit, this sign is used to refer to and comprises first transmission time information in this DTU.And, after receiving the second detection data transmission unit, select a DTU as the second information-bearing data transmission unit, add second receiving time information and sign in this second information-bearing data transmission unit, this sign is used to refer to and comprises second receiving time information in this DTU.

Perhaps, transmitting terminal also can be determined a certain DTU according to preset rule, first transmission time information and second receiving time information is added in this DTU, and sends this DTU to receiving terminal.And this DTU is the 3rd information-bearing data transmission unit.Wherein, described the 3rd information-bearing data transmission unit is by the first time delay channel transfer.

Perhaps, transmitting terminal also can send the administrative messag that comprises first transmission time information to receiving terminal, at this this administrative messag is called first administrative messag, then, transmitting terminal sends the administrative messag that comprises second receiving time information to receiving terminal, at this this administrative messag is called second administrative messag.

Perhaps, transmitting terminal can also send administrative messag to receiving terminal, has wherein comprised first transmission time information and second receiving time information, and this administrative messag is the 3rd administrative messag.

The method for synchronizing time that present embodiment provides, by when the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal equates, transmitting terminal obtains first transmission time information at DTU framer when receiving terminal sends the detection bit of the first detection data transmission unit, transmitting terminal obtains second receiving time information when second of DTU deframer reception receiving terminal transmission detects the detection bit of data transmission unit, and, first transmission time information and second receiving time information are notified to receiving terminal; So that receiving terminal carries out the time synchronized adjustment according to first transmission time information and second receiving time information.Therefore, can be in the xDSL system to realize reaching precise time between the clock of the clock of transmitting terminal and receiving terminal with a kind of simple time synchronized mechanism synchronous, satisfy the needs of mobile service to timing tracking accuracy.Thereby, can in the cost that reduces mobile bearer network, realize that split-second precision is synchronous.

In the above-described embodiments, carry out time synchronized when operation, need the up-downgoing time delay between the pmd layer of the pmd layer of transmitting terminal and receiving terminal to equate.In the existing xDSL system (as ADSL, ADSL 2/2+, VDSL 2 etc.), the up-downgoing time delay between the pmd layer of local side and terminal has symmetry preferably, particularly the VDSL2 system.The structure of existing xDSL can be as shown in Figure 3.In general, master clock is positioned at local side, is positioned at terminal from clock.In embodiments of the present invention, as PMS-TC (Physical Media Specific-Transmission Convergence, physical medium is specific-Transmission Convergence) and when layer had only a time delay passage, DTUframer was positioned at (as shown in Figure 4) before the screambler.Business datum and management data are encapsulated in the data transmission unit by DTU framer.Selectable, when the PMS-TC layer enabled two time delay passages, it (was the passage of p=0, as shown in Figure 5) that DTU framer exists only on the 0th the time delay passage.When the PMS-TC layer enables two time delay passages, only measure the delay inequality that interleaver produced in the 0th the time delay passage.Suppose that Delay1 is the time delay of the pmd layer of local side to the pmd layer of terminal, i.e. the descending time delay of pmd layer, and Delay2 is the time delay of the pmd layer of terminal to the pmd layer of local side, the i.e. uplink time delay of pmd layer.Up-downgoing time delay when between the pmd layer of the pmd layer of local side and terminal is unequal, promptly during Delay1 ≠ Delay2, can make pmd layer up-downgoing time delay equate by certain means, i.e. Delay1=Delay2.For example, obtain pmd layer up-downgoing time delay respectively,, make that uplink time delay and the descending time delay between the pmd layer of the pmd layer of local side and terminal equates that promptly Delay1=Delay2 has symmetry then by the mode of compensation by modes such as measurement, quantifications.

Be example with scene shown in Figure 3 below, by following several modes the foregoing description described in further detail respectively.

Mode one

The present embodiment method for synchronizing time comprises:

When 301, the up-downgoing time delay between the pmd layer of the pmd layer of local side and terminal equated, at local side, DTU framer generated DTU with data and the administrative messag that upper strata (TPS-TC layer) sends, and sends the DTU that is produced to terminal.And, according to setting in advance, the temporal information when local clock (being master clock) obtains DTU framer and sends x bit of a certain specific DTU, i.e. first transmission time information (time stamp T m1).And the time stamp T m1 that local side is obtained is carried among next DTU.

Be specifically as follows: when the up-downgoing time delay of the pmd layer of the pmd layer of local side and terminal equates, at local side, the DTU framer that is positioned at the PMS-TC layer receives data and the administrative messag that sends over from the TPS-TC layer, and data and the administrative messag that receives generated DTU.Wherein, the size of DTU equals the payload of one or more RS code words (wherein, 1 RS code word is the K byte), i.e. n*K byte (n＞=1).Each DTU can be included in the symbol (DMTsymbol) of fixed number, promptly comprises an integer DTU in each symbol, or each DTU is included in the integer symbol, i.e. L _p=k*DTU _Size=k*n*K or k*L _p=DTU _Size(wherein, k and n are and are not less than 1 integer, L=n*K _pBe the bit number that is comprised in the symbol, the i.e. size of a symbol).In addition, when comprising interleaver in the passage of this DTU framer correspondence, the size of interleaver (being D*I) equals one or more RS code words (wherein, the length of a RS code word is the N byte), i.e. D*I=m*N.

Suppose to preestablish DTU framer when generating DTU, reserve t byte at ad-hoc location.According to predetermined rule, select corresponding D TU (being first information carrying data transmission unit), the temporal information of the local clock (master clock) when this DTU framer is sent x bit of previous DTU, promptly timestamp Tm1 is added in t the byte of this reservation.

For example, be example with DTU a, the DTU framer of local side generates DTU a according to data that receive from the TPS-TC layer and administrative messag.When sending x bit of DTU a, obtain the temporal information of local clock, i.e. timestamp Tm1, and shown in Fig. 6 or 7, t byte of reservation carried this time stamp T m1 in DTU a+1.In addition, after DTU framer to send the time stamp T m1 of x bit of DTU a, be not limited to time stamp T m1 is carried among the DTU a+1, also this time stamp T m1 can be carried in t the byte of being reserved among the DTU of other appointments.

302, in terminal, according to setting in advance, the temporal information when obtaining DTU deframer and receive x bit of the DTU that is used for time synchronized that local side sent, i.e. first receiving time information (time stamp T s1) from local clock (promptly from clock).And, when receiving the next DTU of this DTU, the time stamp T m1 when the DTU framer that obtains local side from this next one DTU sends x bit of this DTU.

For example, the DTU deframer of terminal is when receiving x bit of DTU a, obtain the temporal information of local clock, be timestamp Ts1, and, when receiving DTU a+1, DTU a+1 is resolved the time stamp T m1 when from t the byte that this DTU a+1 reserves, obtaining x bit of DTU framer transmission DTU a of local side.

303, in terminal, this DTU framer generates DTU according to data and the administrative messag that upper strata (TPS-TC layer) sends, and sends the DTU that is generated to local side.And, according to setting in advance, the temporal information when obtaining DTU framer and send x bit of each DTU, i.e. second transmission time information (time stamp T s2) from local clock (promptly from clock).

For example, be example with DTU b, in terminal, the DTU framer that is positioned at the PMS-TC layer receives data and the administrative messag that sends over from the TPS-TC layer, and generates DTU b according to data that receive and administrative messag.And DTU framer obtains the temporal information of local clock, i.e. timestamp Ts2 when sending x bit of DTU b.

304, at local side, according to setting in advance, the temporal information when local clock (being master clock) obtains x bit of the DTU that is used for time synchronized that DTU deframer receiving terminal sent, i.e. second receiving time information (time stamp T m2).And, after send to the time stamp T m2 that the carrying local side obtains among the DTU of terminal.

For example, the DTU deframer of local side obtains the temporal information of local clock, i.e. timestamp Tm2 when receiving x bit of DTU b.And, behind the time stamp T m2 when the DTU of local side deframer obtains x the bit that receives DTU b, shown in Fig. 6 or 7, can also in DTU c, reserve t byte, the sequence number of the time stamp T m2 that obtains of carrying and the pairing DTU of this timestamp, and the indication bit that is used to indicate the transmitting-receiving attribute of the timestamp that is carried.Wherein, this indication bit can be set to: indication bit was changed to 1 o'clock, and this timestamp is that the transmitting time of DTU is stabbed; Indication bit was changed to 0 o'clock, and this timestamp is that the time of reception of DTU stabs.At this, this indication bit in t the byte of the reservation of DTU c is changed to 0.Then, send the DTU c that has carried time stamp T m2 to terminal.In addition, in the DTU of the t byte that comprises reservation that transmitting terminal sent, all can be with the sequence number of the pairing DTU of timestamp, and the information-bearings such as indication bit of transmitting-receiving attribute that are used for indicating the timestamp that is carried are in the t of this reservation byte.

In the present embodiment, local side is to stab Tm1 and Tm2 by two DTU difference delivery times, and certainly, local side can also be carried on time stamp T m1 and the Tm2 that obtains among the same DTU, and this DTU is sent to terminal.

305, in terminal, when the DTU of the time stamp T m2 that the DTU deframer of local side receives has been carried in reception, the time stamp T m2 when from this DTU, obtaining x bit of the DTU that the DTU deframer receiving terminal of local side sends.

For example, the DTU deframer of terminal resolves DTU c when receiving DTU c, determines the time stamp T m2 the when timestamp that obtains from this t byte is x bit of DTU deframer reception DTU b of local side.

306,,, carry out the time synchronized adjustment according to time stamp T m1, Ts1, Ts2 and Tm2 in terminal.

Be specifically as follows: under the situation that does not enable to interweave on the passage between transmitting terminal and the receiving terminal, after knowing time stamp T m1, Ts1, Ts2 and Tm2, can obtain equation Tm1+Delay1+Offset=Ts1, and Ts2+Delay2-Offset=Tm2, wherein, Offset is the time offset between principal and subordinate's clock of local side and terminal, Delay1 is that x the bit of DTU is sent to the required time delay of DEMUX module of terminal from the MUX module of local side, and Delay2 is x the bit of DTU is sent to local side from the MUX module of terminal the required time delay of DEMUX module.Because the up-downgoing time delay of the pmd layer of local side and the pmd layer of terminal equates that promptly Delay1=Delay2 can derive equation by above-mentioned equation

Offset＝(Ts1+Ts2-Tm1-Tm2)/2

Under the situation that enables to interweave on the passage between transmitting terminal and the receiving terminal, suppose the time delay of Delay3 for interweaving and produced to direction from clock at master clock, the descending time delay that promptly interweaves and produced, the time delay of Delay4 on the direction from the clock to the master clock, interweaving and produced, the i.e. uplink time delay that interweaves and produced.So, after knowing time stamp T m1, Ts1, Ts2 and Tm2, can obtain equation

Tm1+Delay1+Delay3+Offset＝Ts1；

Ts2+Delay2+Delay4-Offset＝Tm2。

At this moment, do not comprise among Delay1 and the Delay2 by the caused time delay that interweaves of interleaver.When Delay1 ≠ Delay2, need mode by compensation, make Delay1=Delay2.

When the up-downgoing that produces when interweaving interweaves time delay equal (be Delay3=Delay4, or (D-1) * (I-1) equate), can derive equation

Offset＝(Ts1+Ts2-Tm1-Tm2)/2

When the up-downgoing that produces interweaving interweaved time delay unequal (be Delay3 ≠ Delay4, or (D-1) * (I-1) unequal), terminal can obtain the up-downgoing delay inequality Delay that interleaver produced according to the different interleaver calculation of parameter of up-downgoing _Ilv, i.e. Delay3-Delay4=Delay _IlvThus, can derive equation Offset=(Ts1+Ts2-Tm1-Tm2-Delay _Ilv)/2

After terminal calculates Offset according to above-mentioned formula, can adjust local clock (promptly from clock), make master clock and reach time synchronized from clock according to side-play amount Offset.

Mode two

The present embodiment method for synchronizing time comprises:

When 401, the up-downgoing time delay between the pmd layer of the pmd layer of local side and terminal equated, at local side, DTU framer generated DTU according to data and the administrative messag that upper strata (TPS-TC layer) sends, and sends this DTU to terminal.And, according to setting in advance, when between the DTU that the DTU of the current transmission of this DTU framer and a last acquisition time stab, being separated by h DTU, temporal information when local clock (being master clock) obtains this DTU framer and sends x bit of current DTU, i.e. first transmission time information (the time stamp T m1.And the time stamp T m1 that local side is obtained is carried among the next DTU.

Be specifically as follows: when the up-downgoing time delay of the pmd layer of the pmd layer of local side and terminal equates, at local side, the DTU framer that is positioned at the PMS-TC layer receives data and the administrative messag that sends over from the TPS-TC layer, and generates DTU according to data that receive and administrative messag.Suppose to be set in advance in local side or terminal, when generating DTU, the DTU framer that is arranged in the PMS-TC layer reserves t byte at DTU, when between the DTU that the DTU of the current transmission of this DTU framer and a last acquisition time stab, being separated by h DTU, timestamp when local clock (being master clock) obtains this DTU framer and sends x bit of current DTU, and this timestamp is added in t the byte of next DTU reservation.

For example, the DTU framer of local side is according to after the data and administrative messag generation DTU of the reception of TPS-TC layer, timestamp when h DTU obtains once x bit of the current DTU of this DTU frame r transmission, promptly, when being separated by h DTU between the DTU that the DTU a of the current generation of this DTU framer and a last acquisition time stab, the DTU framer of local side obtains the temporal information of local clock, i.e. timestamp Tm1 when sending x bit of DTU a.And, shown in Fig. 6 or 7, in DTU a+1, reserve t byte, carry this time stamp T m1.

In addition, behind the time stamp T m1 when this DTU framer obtains to send x bit of DTU a, be not limited to time stamp T m1 is carried among the DTU a+1, also this time stamp T m1 can be carried in t the byte of reservation of other DTU.

Time stamp T m1 during x the bit that further, can also in the DTU of DTU a that two continuous acquisition times stab and all DTU between the DTU a+h or regulation number, all be somebody's turn to do carrying DTU framer transmission DTUa.And, can in these DTU, carry indication bit, indicate these DTU to carry the number of times of this timestamp with this indication bit, whether be to send this timestamp first perhaps.

For example, behind the timestamp when local side obtains DTU framer and sends x bit of DTU a, carrying time stamp T m1 in t byte of the reservation of DTU a+1, and indication bit is changed to 1, promptly DTU a+1 is the DTU that carries time stamp T m1 the first time.DTU a+2 to DTU a+k (carrying time stamp T m1 in t the predetermined byte of k≤h+1), and indication bit is changed to 0, i.e. DTU a+2 ..., carried time stamp T m1 information among the DTU a+k DTU before.

Perhaps, behind the timestamp when local side obtains DTU framer and sends x bit of DTU a, the time stamp T m1 of carrying DTU a in t byte of the reservation of DTU a+1, and indication bit is changed to 1, promptly DTU a+1 is the DTU that carries time stamp T m1 the first time.DTU a+2 to DTU a+k (carrying time stamp T m1 in t the byte of the reservation of k≤h+1), and indication bit is changed to 2 respectively ..., k, be that DTU a+2 is the DTU that carries time stamp T m1 for the second time ..., DTU a+k is the DTU of the k time carrying time stamp T m1.

402, in terminal, according to setting in advance, when receiving the DTU of h the DTU of being separated by between the DTU with last local side acquisition time stamp, temporal information when obtaining DTU deframer and receive x bit of this DTU, i.e. first receiving time information (time stamp T s1) from local clock (promptly from clock).And, when receiving the next DTU of this DTU, the time stamp T m1 when the DTU framer that obtains local side from this next one DTU sends x bit of this DTU.

For example, when being separated by h DTU between the DTU that a definite DTU a that receives of terminal and a last local side acquisition time stab, the temporal information of the local clock when the DTU deframer of terminal obtains x the bit that receives DTU a, be timestamp Ts1, and, when receiving DTU a+1, DTU a+1 is resolved the time stamp T m1 when from t byte of the reservation of this DTU a+1, obtaining x bit of DTU framer transmission DTU a of local side.

403, in terminal, DTU framer generates DTU according to data and the administrative messag that upper strata (TPS-TC layer) sends, and sends this DTU to local side.And, according to setting in advance, when between the DTU that the DTU of the current transmission of this DTU framer and a last acquisition time stab, being separated by h DTU, temporal information when obtaining this DTU framer and send x bit of current DTU, i.e. second transmission time information (time stamp T s2) from local clock (promptly from clock).

For example, the timestamp of terminal when h DTU obtains x bit of the current DTU of a DTU framer transmission, promptly, when being separated by h DTU between the DTU that a DTU b and a last acquisition time stab, the DTU framer of terminal is when sending x bit of DTU b, obtain the temporal information of local clock, i.e. timestamp Ts2.

404, at local side, according to setting in advance, when receiving the DTU of h the DTU of being separated by between the DTU with last terminal acquisition time stamp, temporal information when local clock (being master clock) obtains DTU deframer and receives x bit of this DTU, i.e. second receiving time information (time stamp T m2).And, after send to the time stamp T m2 that the carrying local side obtains among the DTU of terminal.

For example, when being separated by h DTU between the DTU that a definite DTU b that receives of local side and a last terminal acquisition time stab, the DTU deframer of local side is when receiving x bit of DTU b, obtain the temporal information of local clock, be timestamp Tm2, and, behind the time stamp T m2 when this DTUdeframer obtains x the bit that receives DTU b, can also be shown in Fig. 6 or 7, in DTU c, reserve t byte, the sequence number of the time stamp T m2 that obtains of carrying and the pairing DTU b of this timestamp, and the indication bit that is used to indicate the transmitting-receiving attribute of the timestamp that is carried.Wherein, this indication bit can be set to: the transmitting time that it is DTU that indication bit is changed to 1 o'clock this timestamp is stabbed, and the time of reception that it is DTU that indication bit is changed to 0 o'clock this timestamp stabs.At this, this indication bit in t the byte of the reservation of DTU c is changed to 0.Then, send the DTU c that has carried time stamp T m2 to terminal.

405, in terminal, when the DTU of the time stamp T m2 that the DTU deframer of local side receives has been carried in reception, the time stamp T m2 when from this DTU, obtaining x bit of the DTU that the DTU deframer receiving terminal of local side sends.

For example, terminal is resolved DTU c when receiving DTU c, the time stamp T m2 the when timestamp that obtains from this t byte is x bit of DTU deframer reception DTU b of local side.

406,,, carry out the time synchronized adjustment according to time stamp T m1, Ts1, Ts2 and Tm2 in terminal.The concrete method of adjusting is with reference to step 306, do not do at this and gives unnecessary details.

Mode three

The present embodiment method for synchronizing time comprises:

When 501, the up-downgoing time delay between the pmd layer of the pmd layer of local side and terminal equated, at local side, DTU framer generated DTU according to data and the administrative messag that upper strata (TPS-TC layer) sends, and sends this DTU to terminal.And, according to setting in advance, the temporal information when local clock (being master clock) obtains this DTU framer and sends x bit of each DTU, i.e. first transmission time information (the time stamp T m1.And the time stamp T m1 that local side is obtained is carried in the administrative messag (as eoc message) of regulation, sends to terminal by embedded channel.

502, in terminal, according to setting in advance, the temporal information when obtaining DTU deframer and receive x bit of each DTU, i.e. first receiving time information (time stamp T s1) from local clock (promptly from clock).And, by embedded channel receiving management message, and the time stamp T m1 of the DTU framer that from this administrative messag, obtains local side when sending x bit of this DTU.

503, in terminal, DTU framer generates DTU according to data and the administrative messag that upper strata (TPS-TC layer) sends, and sends this DTU to local side.And, according to setting in advance, the temporal information when obtaining DTU framer and send x bit of each DTU, i.e. second transmission time information (time stamp T s2) from local clock (promptly from clock).

504, at local side, according to setting in advance, the temporal information when local clock (being master clock) obtains DTU deframer and receives x bit of each DTU, i.e. second receiving time information (time stamp T m2).And the time stamp T m2 that local side is obtained is carried in the administrative messag (as eoc message) of regulation, sends to terminal by embedded channel.

At this, local side is to stab Tm1 and Tm2 by two administrative messags difference delivery times, and certainly, local side can also be carried on time stamp T m1 and the Tm2 that obtains in the same administrative messag, sends to terminal by embedded channel.

505, in terminal, by embedded channel receiving management message, and the time stamp T m2 of the DTU deframer that from this administrative messag, obtains local side when receiving x bit of this DTU.

506,,, carry out the time synchronized adjustment according to time stamp T m1, Ts1, Ts2 and Tm2 in terminal.The concrete method of adjusting is with reference to step 306, do not do at this and gives unnecessary details.

Optionally, fail safe and accuracy for timestamp in guaranteeing to transmit, can also be in the above-described embodiments, the timestamp and the relevant information thereof of being carried in t the byte to the reservation of DTU are carried out verification operation, for example, adopt CRC (Cyclical Redundancy Check, CRC) or Gray (Golay) sign indicating number to wait the check information that obtains timestamp and relevant information thereof, and this check information is carried in t the byte of reservation of DTU.

Optionally, can also make DTU framer dateout evenly in the above-described embodiments, thereby guarantee the stability of PMS-TC layer time delay, make the time synchronized operation more accurate.Further, can also make PMS-TC layer dateout evenly in the above-described embodiments, guarantee that the pmd layer input rate is constant, and then make that the interface time delay of PMS-TC layer and pmd layer is stable.Thereby, equate that from the up-downgoing time delay that outputs between the PMS-TC layer input of opposite end of PMS-TC layer i.e. up-downgoing time delay has symmetry.

In addition, in the above-described embodiments, the mode that local side and terminal acquisition time stab all is predefined, but also can local side and terminal consult to determine the mode of acquisition time stamp by administrative messag.

The method for synchronizing time that embodiment under above-mentioned each mode provides, by when the up-downgoing time delay between the pmd layer of the pmd layer of local side and terminal equates, local side sends first first transmission time information when detecting the detection bit of data transmission unit with DTU framer and is notified to terminal, terminal is obtained DTU deframer and is received this and first obtain first receiving time information when detecting the detection bit of data transmission unit, and, terminal is obtained DTU framer and is sent second second transmission time information when detecting the detection bit of data transmission unit, local side receives second second receiving time information when detecting the detection bit of data transmission unit with DTUdeframer and is notified to terminal, then, terminal is according to first transmission time information, first receiving time information, second transmission time information and second receiving time information time of carrying out is adjusted, and makes the clock of terminal and the clock of local side reach time synchronized.Thereby it is synchronous to reach precise time with the principal and subordinate's clock between a kind of simple time synchronized mechanism realization local side and the terminal in the xDSL system, satisfies the needs of mobile service to timing tracking accuracy.Therefore, can in the cost that reduces mobile bearer network, realize that split-second precision is synchronous.

In addition, when local side and terminal have a plurality of time delay passage, can only on a time delay passage between local side and the terminal, above-mentioned DTU framer and DTU deframer be set, carry out master clock and from the time synchronized between the clock.Thereby, realize that with a spot of device split-second precision is synchronous.

With said method accordingly, the embodiment of the invention also provides a kind of time synchronism apparatus, as shown in Figure 8, comprising:

Data transmission unit parse for frame module 801 is used for the first detection data transmission unit that receiving end/sending end sends; Perhaps, receive first transmission time information and second receiving time information that described transmitting terminal sends, the data transmission unit that described first transmission time information is described transmitting terminal becomes frame module to send described first the temporal information when detecting the detection bit of data transmission unit, and the data transmission unit parse for frame module that described second receiving time information is described transmitting terminal receives described second the temporal information when detecting the detection bit of data transmission unit;

Data transmission unit becomes frame module 802, is used to generate second and detects data transmission unit, and send the described second detection data transmission unit to described transmitting terminal;

Clock acquisition module 803 is used to obtain first receiving time information, and described first receiving time information is that described data transmission unit parse for frame module 801 receives described first the temporal information when detecting the detection bit of data transmission unit; Perhaps, obtain second transmission time information, described second transmission time information is that described data transmission unit becomes frame module 802 to send described second the temporal information when detecting the detection bit of data transmission unit;

Correct module 804, be used for when the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal equates, first receiving time information and second transmission time information that obtain according to described clock acquisition module 803, first transmission time information that described data transmission unit parse for frame module 801 receives and second receiving time information time of carrying out are adjusted, and make the clock of described receiving terminal and the clock of described transmitting terminal reach time synchronized.

Further, described data transmission unit parse for frame module 801 specifically comprises:

Parse for frame Data Receiving unit is used to receive the first detection data transmission unit or first information carrying data transmission unit or the second information-bearing data transmission unit or the 3rd information-bearing data transmission unit that described transmitting terminal sends;

The parse for frame time acquisition unit, the first information carrying data transmission unit that is used for receiving from described parse for frame Data Receiving unit is obtained first transmission time information; Perhaps, from the second information-bearing data transmission unit that described parse for frame Data Receiving unit receives, obtain second receiving time information; Perhaps, from the 3rd information-bearing data transmission unit that described parse for frame Data Receiving unit receives, obtain first transmission time information and second receiving time information.

Further, described parse for frame Data Receiving unit specifically is used for receiving described first information carrying data transmission unit or the second information-bearing data transmission unit or the 3rd information-bearing data transmission unit by the first time delay passage.

Perhaps, described data transmission unit parse for frame module 801 specifically comprises:

Parse for frame Data Receiving unit is used to receive the first detection data transmission unit that described transmitting terminal sends;

The message sink unit is used for first administrative messag or second administrative messag or the 3rd administrative messag that receiving end/sending end sends;

The parse for frame time acquisition unit, first administrative messag that is used for receiving from described message sink unit obtains first transmission time information; Perhaps, from second administrative messag that described message sink unit receives, obtain second receiving time information; Perhaps, from the 3rd administrative messag that described message sink unit receives, obtain first transmission time information and second receiving time information.

Further, described correction module 804 specifically comprises:

The side-play amount acquiring unit, be used for up-downgoing when interleaver and interweave time delay when equating, according to the described first transmission time information Tm1, the described first receiving time information Ts1, the described second transmission time information Ts2, described second receiving time information Tm2 and formula Offset=(Ts1+Ts2-Tm1-Tm2)/2, acquisition time side-play amount Offset;

The time adjustment unit, the time offset Offset that is used for obtaining according to described side-play amount acquiring unit adjusts the clock of receiving terminal, makes the clock of receiving terminal and the clock of described transmitting terminal reach time synchronized.

Perhaps, described correction module 804 specifically comprises:

Delay inequality acquiring unit, the up-downgoing that is used to the to obtain interleaver delay inequality Delay that interweaves _Ilv

The side-play amount acquiring unit is used for according to the described first transmission time information Tm1, the described first receiving time information Ts1, the described second transmission time information Ts2, the described second receiving time information Tm2, the up-downgoing of the interleaver delay inequality Delay that interweaves _IlvAnd formula Offset=(Ts1+Ts2-Tm1-Tm2-Delay _Ilv)/2, acquisition time side-play amount Offset;

The time adjustment unit, the time offset Offset that is used for obtaining according to described side-play amount acquiring unit adjusts the clock of receiving terminal, makes the clock of described receiving terminal and the clock of described transmitting terminal reach time synchronized.

The time synchronism apparatus that present embodiment provides, by when the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal equates, receiving terminal first is obtained first receiving time information when detecting the detection bit of data transmission unit what DTU deframer receiving end/sending end sent, receiving terminal obtains second transmission time information when sending the detection bit of the second detection data transmission unit to transmitting terminal, and, first transmission time information and second receiving time information that receiving end/sending end sends; Then, according to first transmission time information, first receiving time information, second transmission time information and second receiving time information carry out the time synchronized adjustment.Therefore, can be in the xDSL system to realize reaching precise time between the clock of the clock of transmitting terminal and receiving terminal with a kind of simple time synchronized mechanism synchronous, satisfy the needs of mobile service to timing tracking accuracy.Thereby, can in the cost that reduces mobile bearer network, realize that split-second precision is synchronous.

Corresponding with said apparatus, the embodiment of the invention also provides a kind of time synchronism apparatus, as shown in Figure 9, comprising:

Data transmission unit becomes frame module 901, and be used for sending first and detect data transmission unit to receiving terminal, and first transmission time information and second receiving time information that obtain to described receiving terminal tranmitting data register acquisition module;

Data transmission unit parse for frame module 902 is used to receive the second detection data transmission unit that described receiving terminal sends;

Clock acquisition module 903 is used to obtain first transmission time information, and described first transmission time information is that described data transmission unit becomes frame module 901 to send described first the temporal information when detecting the detection bit of data transmission unit; Perhaps, obtain second receiving time information, described second receiving time information is that described data transmission unit parse for frame module 902 receives described second the temporal information when detecting the detection bit of data transmission unit.

Further, described data transmission unit becomes frame module 901 specifically to comprise:

Generate data cell, be used for basis setting in advance and generate the first detection data transmission unit or first information carrying data transmission unit or the second information-bearing data transmission unit or the 3rd information-bearing data transmission unit, described first information carrying data transmission unit comprises described first transmission time information, the described second information-bearing data transmission unit comprises described second receiving time information, and described the 3rd information-bearing data transmission unit comprises described first transmission time information and described second receiving time information;

Send data cell, be used for sending the first detection data transmission unit or first information carrying data transmission unit or the second information-bearing data transmission unit or the 3rd information-bearing data transmission unit that described generation data cell generates to described receiving terminal.

Further, described transmission data cell specifically is used for sending first information carrying data transmission unit or the second information-bearing data transmission unit or the 3rd information-bearing data transmission unit by the first time delay passage to described receiving terminal.

Perhaps, described data transmission unit becomes frame module 901 specifically to comprise:

Generate data cell, be used for basis setting in advance and generate the first detection data transmission unit;

Send data cell, be used for sending the first detection data transmission unit that described generation data cell generates to described receiving terminal

Message sending unit is used for sending first administrative messag to described receiving terminal, and described first administrative messag comprises first transmission time information that described clock acquisition module obtains; Perhaps, send second administrative messag to described receiving terminal, described second administrative messag comprises second receiving time information that described clock acquisition module obtains; Perhaps, send the 3rd administrative messag to described receiving terminal, described the 3rd administrative messag comprises first transmission time information and second receiving time information that described clock acquisition module obtains.

The time synchronism apparatus that present embodiment provides, by when the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal equates, transmitting terminal obtains first transmission time information at DTU framer when receiving terminal sends the detection bit of the first detection data transmission unit, transmitting terminal obtains second receiving time information when second of DTU deframer reception receiving terminal transmission detects the detection bit of data transmission unit, and first transmission time information and second receiving time information be notified to receiving terminal, so that receiving terminal carries out the time synchronized adjustment according to first transmission time information and second receiving time information.Therefore, can be in the xDSL system to realize reaching precise time between the clock of the clock of transmitting terminal and receiving terminal with a kind of simple time synchronized mechanism synchronous, satisfy the needs of mobile service to timing tracking accuracy.Thereby, can in the cost that reduces mobile bearer network, realize that split-second precision is synchronous.

With said method, the device corresponding, the embodiment of the invention also provides a kind of clock synchronization system, as shown in figure 10, comprises transmitting terminal 1001 and receiving terminal 1002;

Described transmitting terminal 1001, be used for when the up-downgoing time delay between the pmd layer of the pmd layer of transmitting terminal 1001 and receiving terminal 1002 equates, obtaining first transmission time information when detecting data transmission unit sending first to receiving terminal 1002, the DTU framer that described first transmission time information is described transmitting terminal 1001 sends described first the temporal information when detecting the detection bit of data transmission unit; Second obtain second receiving time information when detecting data transmission unit what receive that receiving terminal 1002 sends, described second receiving time information receives described second the temporal information when detecting the detection bit of data transmission unit for local DTUdeframer; Send described first transmission time information and described second receiving time information to described receiving terminal 1002;

Described receiving terminal 1002, be used for first obtaining first receiving time information when detecting data transmission unit what receiving end/sending end 1001 sent, the DTU deframer that described first receiving time information is described receiving terminal 1002 receives described first the temporal information when detecting the detection bit of data transmission unit; Obtaining second transmission time information when detecting data transmission unit sending second to described transmitting terminal 1001, the DTU framer that described second transmission time information is described receiving terminal 1002 sends described second the temporal information when detecting the detection bit of data transmission unit; Receive first transmission time information and second receiving time information that described transmitting terminal 1001 sends; According to described first transmission time information, described first receiving time information, described second transmission time information and described second receiving time information time of carrying out is adjusted, and makes the clock of described receiving terminal 1002 and the clock of described transmitting terminal 1001 reach time synchronized.

Further, described receiving terminal 1002, specifically be used for up-downgoing when interleaver and interweave time delay when equating, according to the described first transmission time information Tm1, the described first receiving time information Ts1, the described second transmission time information Ts2, described second receiving time information Tm2 and formula Offset=(Ts1+Ts2-Tm1-Tm2)/2, acquisition time side-play amount Offset; And, make the clock of described receiving terminal 1002 and the clock of described transmitting terminal 1001 reach time synchronized according to the clock that described time offset 0ffset adjusts described receiving terminal.

Further, described receiving terminal 1002, the up-downgoing that specifically is used to the to obtain interleaver delay inequality Delay that interweaves _IlvAccording to the described first transmission time information Tm1, the described first receiving time information Ts1, the described second transmission time information Ts2, the described second receiving time information Tm2, the up-downgoing of the interleaver delay inequality Delay that interweaves _IlvAnd formula Offset=(Ts1+Ts2-Tm1-Tm2-Delay _Ilv)/2, acquisition time side-play amount Offset; Adjust the clock of described receiving terminal according to described time offset Offset, make the clock of clock 1002 and described transmitting terminal 1001 of described receiving terminal reach time synchronized.

The method for synchronizing time that the embodiment of the invention provides, Apparatus and system, by when the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal equates, transmitting terminal sends first first transmission time information when detecting the detection bit of data transmission unit with DTUframer and is notified to receiving terminal, receiving terminal obtains DTU deframer and receives this first first receiving time information when detecting the detection bit of data transmission unit, and, receiving terminal obtains DTUframer and sends second second transmission time information when detecting the detection bit of data transmission unit, transmitting terminal receives second second receiving time information when detecting the detection bit of data transmission unit with DTU deframer and is notified to receiving terminal, then, receiving terminal is according to first transmission time information, first receiving time information, second transmission time information and second receiving time information time of carrying out is adjusted, and makes the clock of receiving terminal and the clock of transmitting terminal reach time synchronized.Thereby, can be in the xDSL system realize that with a kind of simple time synchronized mechanism precise time is synchronous between the clock of the clock of transmitting terminal and receiving terminal, satisfy the needs of mobile service to timing tracking accuracy.Therefore, can in the cost that reduces mobile bearer network, realize that split-second precision is synchronous.

One of ordinary skill in the art will appreciate that all or part of flow process that realizes in the foregoing description method, be to instruct relevant hardware to finish by computer program, described program can be stored in the computer read/write memory medium, this program can comprise the flow process as the embodiment of above-mentioned each side method when carrying out.Wherein, described storage medium can be magnetic disc, CD, read-only storage memory body (Read-Only Memory, ROM) or at random store memory body (Random Access Memory, RAM) etc.

The above; only be the specific embodiment of the present invention, but protection scope of the present invention is not limited thereto, anyly is familiar with those skilled in the art in the technical scope that the present invention discloses; can expect easily changing or replacing, all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion by described protection range with claim.

Claims

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

When the up-downgoing time delay between the pmd layer of the relevant pmd layer of the physical medium of receiving terminal and transmitting terminal equates, when receiving the first detection data transmission unit of described transmitting terminal transmission, obtain first receiving time information, the data transmission unit parse for frame module DTU deframer that described first receiving time information is described receiving terminal receives described first the temporal information when detecting the detection bit of data transmission unit;

When sending the second detection data transmission unit to described transmitting terminal, obtain second transmission time information, the data transmission unit that described second transmission time information is described receiving terminal becomes frame module DTU framer to send described second the temporal information when detecting the detection bit of data transmission unit;

2. method for synchronizing time according to claim 1 is characterized in that, first transmission time information and second receiving time information that the described transmitting terminal of described reception sends comprise:

Receive the first information carrying data transmission unit that described transmitting terminal sends;

From described first information carrying data transmission unit, obtain first transmission time information;

Receive the second information-bearing data transmission unit that described transmitting terminal sends;

From the described second information-bearing data transmission unit, obtain second receiving time information;

The described first information carrying data transmission unit or the second information-bearing data transmission unit are by the first time delay channel transfer.

3. method for synchronizing time according to claim 1 is characterized in that, first transmission time information and second receiving time information that the described transmitting terminal of described reception sends comprise:

Receive the 3rd information-bearing data transmission unit that described transmitting terminal sends;

From described the 3rd information-bearing data transmission unit, obtain first transmission time information and second receiving time information;

Described the 3rd information-bearing data transmission unit is by the first time delay channel transfer.

4. method for synchronizing time according to claim 1 is characterized in that, first transmission time information and second receiving time information that the described transmitting terminal of described reception sends comprise:

Receive first administrative messag that described transmitting terminal sends;

From described first administrative messag, obtain first transmission time information;

Receive second administrative messag that described transmitting terminal sends;

From described second administrative messag, obtain second receiving time information;

First transmission time information and second receiving time information that the described transmitting terminal of described reception sends comprise:

Receive the 3rd administrative messag that described transmitting terminal sends;

From described the 3rd administrative messag, obtain first transmission time information and second receiving time information.

5. method for synchronizing time according to claim 1, it is characterized in that, described according to described first transmission time information, described first receiving time information, described second transmission time information and described second receiving time information time of carrying out is adjusted, and makes the clock of the clock of described receiving terminal and described transmitting terminal reach time synchronized and comprises:

When the up-downgoing of interleaver interweaves time delay when equating, according to the described first transmission time information Tm1, the described first receiving time information Ts1, the described second transmission time information Ts2, described second receiving time information Tm2 and formula Offset=(Ts1+Ts2-Tm1-Tm2)/2, acquisition time side-play amount Offset;

Adjust the clock of described receiving terminal according to described time offset Offset, make the clock of described receiving terminal and the clock of described transmitting terminal reach time synchronized.

6. method for synchronizing time according to claim 1, it is characterized in that, described according to described first transmission time information, described first receiving time information, described second transmission time information and described second receiving time information time of carrying out is adjusted, and makes the clock of the clock of described receiving terminal and described transmitting terminal reach time synchronized and comprises:

The up-downgoing of the obtaining interleaver delay inequality Delay that interweaves _Ilv

According to the described first transmission time information Tm1, the described first receiving time information Ts1, the described second transmission time information Ts2, the described second receiving time information Tm2, the up-downgoing of the interleaver delay inequality Delay that interweaves _IlvAnd formula Offset=(Ts1+Ts2-Tm1-Tm2-Delay _Ilv)/2, acquisition time side-play amount Offset;

7. according to the arbitrary described method for synchronizing time of claim 1-6, it is characterized in that, also comprise:

Obtain the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal;

When the up-downgoing time delay between the pmd layer of the pmd layer of described receiving terminal and described transmitting terminal is unequal, adjust by the mode of compensation, make that the up-downgoing time delay between the pmd layer of pmd layer and described transmitting terminal of described receiving terminal equates.

8. a time synchronism apparatus is characterized in that, comprising:

Data transmission unit parse for frame module is used for the first detection data transmission unit that receiving end/sending end sends; Perhaps, receive first transmission time information and second receiving time information that described transmitting terminal sends, the data transmission unit that described first transmission time information is described transmitting terminal becomes frame module to send described first the temporal information when detecting the detection bit of data transmission unit, and the data transmission unit parse for frame module that described second receiving time information is described transmitting terminal receives described second the temporal information when detecting the detection bit of data transmission unit;

Correct module, be used for when the up-downgoing time delay between the pmd layer of the pmd layer of receiving terminal and transmitting terminal equates, first receiving time information and second transmission time information that obtain according to described clock acquisition module, first transmission time information that described data transmission unit parse for frame module receives and second receiving time information time of carrying out is adjusted, and makes the clock of described receiving terminal and the clock of described transmitting terminal reach time synchronized.

9. time synchronism apparatus according to claim 8 is characterized in that, described data transmission unit parse for frame module comprises:

10. time synchronism apparatus according to claim 8 is characterized in that, described data transmission unit parse for frame module comprises:

The message sink unit is used to receive first administrative messag or second administrative messag or the 3rd administrative messag that described transmitting terminal sends;

11. time synchronism apparatus according to claim 10, it is characterized in that, described parse for frame Data Receiving unit specifically is used for receiving described first information carrying data transmission unit or the second information-bearing data transmission unit or the 3rd information-bearing data transmission unit by the first time delay passage.

12. arbitrary according to Claim 8-11 described time synchronism apparatus is characterized in that, described correction module comprises:

The side-play amount acquiring unit is used for up-downgoing when interleaver and interweaves time delay when equating, according to the described first transmission time information Tm1, the described first receiving time information Ts1, the described second transmission time information Ts2, the described second receiving time information Tm2, acquisition time side-play amount Offset;

13. arbitrary according to Claim 8-11 described time synchronism apparatus is characterized in that, described correction module comprises:

The side-play amount acquiring unit is used for according to the described first transmission time information Tm1, the described first receiving time information Ts1, the described second transmission time information Ts2, the described second receiving time information Tm2, the up-downgoing of the interleaver delay inequality Delay that interweaves _Ilv, acquisition time side-play amount Offset;

14. a time synchronism apparatus is characterized in that, comprising:

15. time synchronism apparatus according to claim 14 is characterized in that, described data transmission unit becomes frame module to comprise:

16. a clock synchronization system is characterized in that, comprises transmitting terminal and receiving terminal;

Described transmitting terminal, be used for when the up-downgoing time delay between the pmd layer of the pmd layer of described transmitting terminal and described receiving terminal equates, obtaining first transmission time information when detecting data transmission unit sending first to described receiving terminal, the DTU framer that described first transmission time information is described transmitting terminal sends described first the temporal information when detecting the detection bit of data transmission unit; Second obtain second receiving time information when detecting data transmission unit what receive that described receiving terminal sends, the DTU deframer that described second receiving time information is described transmitting terminal receives described second the temporal information when detecting the detection bit of data transmission unit; Send described first transmission time information and described second receiving time information to described receiving terminal;

Described receiving terminal, be used for first obtaining first receiving time information when detecting data transmission unit what receive that described transmitting terminal sends, the DTU deframer that described first receiving time information is described receiving terminal receives described first the temporal information when detecting the detection bit of data transmission unit; Obtaining second transmission time information when detecting data transmission unit sending second to described transmitting terminal, the DTU framer that described second transmission time information is described receiving terminal sends described second the temporal information when detecting the detection bit of data transmission unit; Receive first transmission time information and second receiving time information that described transmitting terminal sends; According to described first transmission time information, described first receiving time information, described second transmission time information and described second receiving time information time of carrying out is adjusted, and makes the clock of described receiving terminal and the clock of described transmitting terminal reach time synchronized.

17. clock synchronization system according to claim 16, it is characterized in that, described receiving terminal, specifically be used for up-downgoing when interleaver and interweave time delay when equating, according to the described first transmission time information Tm1, the described first receiving time information Ts1, the described second transmission time information Ts2, described second receiving time information Tm2 and formula Offset=(Ts1+Ts2-Tm1-Tm2)/2, acquisition time side-play amount Offset; And, make the clock of described receiving terminal and the clock of described transmitting terminal reach time synchronized according to the clock that described time offset Offset adjusts described receiving terminal.

18. clock synchronization system according to claim 16 is characterized in that, described receiving terminal, the up-downgoing that specifically is used to the to obtain interleaver delay inequality Delay that interweaves _IlvAccording to the described first transmission time information Tm1, the described first receiving time information Ts1, the described second transmission time information Ts2, the described second receiving time information Tm2, the up-downgoing of the interleaver delay inequality Delay that interweaves _IlvAnd formula Offset=(Ts1+Ts2-Tm1-Tm2-Delay _Ilv)/2, acquisition time side-play amount Offset; Adjust the clock of described receiving terminal according to described time offset Offset, make the clock of described receiving terminal and the clock of described transmitting terminal reach time synchronized.