CN102143571B

CN102143571B - Time synchronization method, DSL equipment and broadband access network system

Info

Publication number: CN102143571B
Application number: CN201010111341.8A
Authority: CN
Inventors: 徐贵今; 刘建华; 冯儒洲; 龙国柱
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2010-02-02
Filing date: 2010-02-02
Publication date: 2014-01-08
Anticipated expiration: 2030-02-02
Also published as: CN102143571A

Abstract

The embodiment of the invention provides a time synchronization method, DSL equipment and a broadband access network system. The time synchronization method comprises the following steps: second equipment acquires a first transmission time for first equipment to transmit a first time synchronization signal to the second equipment, receives a first receiving time for receiving the first time synchronization signal and sacquires a second transmission time for the second equipment to transmit a second time synchronization signal to the first equipment, and the first equipment receives a second receiving time for receiving the second time synchronization signal; the clock offset between the first equipment and the second equipment is calculated according to the first transmission time and the first receiving time, and the second transmission time and the second receiving time; the time of the second equipment is adjusted according to the clock offset. With the embodiment of the invention, time synchronization can be achieved in a digital subscriber line system, and the synchronization precision is high.

Description

Method for synchronizing time, dsl device and wide-band cut-in network system

Technical field

The present invention relates to communication technical field, particularly a kind of method for synchronizing time, digital subscriber line (DSL, Digital Subscriber Line) equipment and wide-band cut-in network system.

Background technology

Along with the development of the communication technology, mobile service is more and more higher to the requirement of time synchronized, has reached the requirement of Microsecond grade.At present, for the needs that meet high precision clock and time synchronized have been developed IEEE 1588 agreements, by calculating the time deviation from clock and master clock, will be from the clock synchronous to the master clock.

For most systems, as optical fiber, Ethernet connecting system, can calculate at an easy rate from the time deviation of clock and master clock, thus will be from the clock synchronous to the master clock.

But the inventor finds that the defect of prior art is in realizing process of the present invention: for digital subscriber line (the DSL:Digital Subscriber Line) system that adopts Discrete multi-tone (DMT:Discrete Multi-tone) modulation technique, because its signal is transmitted with continual symbol one by one, there is no obvious boundary line between symbol and symbol, be not easy to find synchronous point to carry out time mark, therefore, for this system, also do not have at present concrete method to realize time synchronized; In addition, because the up-downgoing delay-time difference of channel in this system is larger, cause time error larger, therefore, can not meet the needs of mobile carrying.

Summary of the invention

The embodiment of the present invention provides a kind of method for synchronizing time, dsl device and wide-band cut-in network system, by the first equipment and the second equipment, the default bit of uplink and downlink signals in transmission convergence sublayer reads local zone time, make the second equipment obtain the transmitting-receiving time of uplink and downlink signals in digital line system, and according to the Time Calculation clock offset obtained, thereby realized the time synchronization problem in the digital line system.

A kind of method for synchronizing time of the embodiment of the present invention, this method for synchronizing time comprises:

The second equipment obtains the first equipment and sends the second transmitting time Ts2 of the second time synchronizing signal and the second time of reception Tm2 that the first equipment receives the second time synchronizing signal to the first transmitting time Tm1 of the second equipment transmission very first time synchronizing signal and the first time of reception Ts1 and second equipment that obtains of the second equipment reception very first time synchronizing signal to the first equipment;

Calculate the clock offset between the second equipment and the first equipment according to the first transmitting time Tm1 and the first time of reception Ts1 and the second transmitting time Ts2 and the second time of reception Tm2;

Adjust the time of the second equipment according to clock offset;

Wherein, in transmission convergence sublayer, first of very first time synchronizing signal the default bit reads local zone time and obtains the first transmitting time Tm1 and the first time of reception Ts1; In transmission convergence sublayer, second of the second time synchronizing signal the default bit reads local zone time and obtains the second transmitting time Ts2 and the second time of reception Tm2.

The embodiment of the present invention provides a kind of user side dsl device, and this user side dsl device comprises:

Time acquisition unit, the first transmitting time Tm1 that sends very first time synchronizing signal for obtaining local side DSL access and multiplexing device to this user side dsl device receives the first time of reception Ts1 of described very first time synchronizing signal and obtains described user side dsl device with this user side dsl device and sends the second transmitting time Ts2 of the second time synchronizing signal and the second time of reception Tm2 that described local side DSL access and multiplexing device receives described the second time synchronizing signal to described local side DSL access and multiplexing device;

The side-play amount computing unit, calculate the clock offset between described user side dsl device and described local side DSL access and multiplexing device for described the first transmitting time Tm1 of obtaining according to described time acquisition unit and the first time of reception Ts1 and described the second transmitting time Ts2 and the second time of reception Tm2;

The time adjustment unit, adjust time of described user side dsl device for the described clock offset obtained according to described side-play amount computing unit;

Wherein, read local zone time at the first default bit of the synchronizing signal of the very first time described in transmission convergence sublayer and obtain described the first transmitting time Tm1 and described the first time of reception Ts1; Read local zone time at the second default bit of the second time synchronizing signal described in transmission convergence sublayer and obtain described the second transmitting time Ts2 and described the second time of reception Tm2.

The embodiment of the present invention provides a kind of local side DSL access and multiplexing device, and this local side DSL access and multiplexing device comprises:

The first processing unit, send to described user side dsl device for the first transmitting time Tm1 that described local side DSL access and multiplexing device is sent to very first time synchronizing signal to the user side dsl device, make described user side dsl device obtain the transmitting time Tm1 of described very first time synchronizing signal;

The second processing unit, the second time of reception Tm2 for the second time synchronizing signal that described user side dsl device is sent to described local side DSL access and multiplexing device sends to described user side dsl device, makes described user side dsl device obtain the time of reception Tm2 of described the second time synchronizing signal;

Wherein, read local zone time at the first default bit of the synchronizing signal of the very first time described in transmission convergence sublayer and obtain described the first transmitting time Tm1; Read local zone time at the second default bit of the second time synchronizing signal described in transmission convergence sublayer and obtain described the second time of reception Tm2.

The embodiment of the present invention provides a kind of wide-band cut-in network system, and this wide-band cut-in network system comprises the transmission line between local side DSL access and multiplexing device, user side dsl device and local side DSL access and multiplexing device and user side dsl device.

The beneficial effect of the embodiment of the present invention is, by the first equipment and the second equipment, the default bit of uplink and downlink signals in transmission convergence sublayer reads local zone time, make the second equipment obtain the transmitting-receiving time of uplink and downlink signals in digital line system, and according to the Time Calculation clock offset obtained, thereby realized the time synchronization problem in the digital line system.

The accompanying drawing explanation

Accompanying drawing described herein is used to provide a further understanding of the present invention, forms the application's a part, does not form limitation of the invention.In the accompanying drawings:

Fig. 1 is the flow chart of the method for synchronizing time of the embodiment of the present invention 1;

Fig. 2 is the flow chart of the method for synchronizing time of the embodiment of the present invention 2;

Fig. 3 is the DSL system construction drawing of the embodiment of the present invention 2;

Fig. 4 is the flow chart of the method for synchronizing time of the embodiment of the present invention 3;

Fig. 5 is the flow chart that obtains time of delay of the embodiment of the present invention 3;

Fig. 6 is the schematic diagram that obtains time of delay of the embodiment of the present invention 3;

Fig. 7 is that another of the embodiment of the present invention 3 obtains the schematic diagram of time of delay;

Fig. 8 is the pie graph of the user side dsl device of the embodiment of the present invention 4;

Fig. 9 is the pie graph of the time acquisition unit of the embodiment of the present invention 5;

Figure 10 is the pie graph of the first acquiring unit of the embodiment of the present invention 5;

Figure 11 is the pie graph of the second acquisition unit of the embodiment of the present invention 5;

Figure 12 is the pie graph of the local side DSL access and multiplexing device of the embodiment of the present invention 6;

Figure 13 is the pie graph of the first processing unit of the embodiment of the present invention 7;

Figure 14 is the pie graph of the 5th acquiring unit of the embodiment of the present invention 7;

Figure 15 is the pie graph of the second processing unit of the embodiment of the present invention 7;

Figure 16 is the pie graph of the 6th acquiring unit of the embodiment of the present invention 7;

Figure 17 is the pie graph of the wide-band cut-in network system of the embodiment of the present invention 8.

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, below in conjunction with accompanying drawing, the embodiment of the present invention is described in further detail.At this, schematic description and description of the present invention is for explaining the present invention, but not as a limitation of the invention.

Embodiment 1

The embodiment of the present invention provides a kind of method for synchronizing time, and as shown in Figure 1, the method comprises:

Step 101, the second equipment obtains the first equipment to the first transmitting time Tm1 of the second equipment transmission very first time synchronizing signal and this second equipment receives the first time of reception Ts1 of this very first time synchronizing signal and second equipment that obtains sends the second transmitting time Ts2 of the second time synchronizing signal and the second time of reception Tm2 that this first equipment receives this second time synchronizing signal to the first equipment;

Wherein, in transmission convergence sublayer, first of this very first time synchronizing signal the default bit reads local zone time and obtains this first transmitting time Tm1 and this first time of reception Ts1; In transmission convergence sublayer, second of this second time synchronizing signal the default bit reads local zone time and obtains this second transmitting time Ts2 and this second time of reception Tm2.

Step 102, the second equipment calculates the clock offset between this second equipment and the first equipment according to this first transmitting time Tm1 and the first time of reception Ts1 and this second transmitting time Ts2 and the second time of reception Tm2.

Step 103, the second equipment is adjusted the time of this second equipment according to this clock offset.

In the present embodiment, this very first time synchronizing signal can be the downstream signal in digital line system; This second time synchronizing signal can be the upward signal in digital line system.This transmission convergence sublayer (TC, Transmission Convergence) can comprise the host-host protocol convergence sub-layer (TPS-TC that is correlated with, Transmission Protocol Specific TC) convergence sub-layer relevant with physical medium (PMS-TC, Physical Media-Specific TC).

In the present embodiment, clock offset can be expressed as Offset, and the formula that calculates this clock offset Offset can be: Offset=(Ts1+Ts2-Tm1-Tm2)/2.Adjust the clock of this second equipment according to this clock offset, like this, can be by synchronizeing with master clock from clock in digital subscriber line.

In the present embodiment, this first equipment can be local side DSL access and multiplexing device (DSLAM, DSL AccessMultiplexer), for example, can be Remote Interface Unit (CO, Remote Terminal Unit), this second equipment can be the user side dsl device, can be DSL modulator-demodulator (DSL Modem), for example can be subscriber terminal equipment (CPE:Customer Premises Equipment).

From above-described embodiment, by the first equipment and the second equipment, the default bit of uplink and downlink signals in transmission convergence sublayer reads local zone time, make the second equipment obtain the transmitting-receiving time of uplink and downlink signals in digital line system, and according to the Time Calculation clock offset obtained, thereby realized the time synchronization problem in the digital line system.

Embodiment 2

The embodiment of the present invention provides a kind of method for synchronizing time, and as shown in Figure 2, the method comprises:

Step 201, the first transmitting time Tm1 that the first equipment sends very first time synchronizing signal by this first equipment to the second equipment sends to this second equipment, makes this second equipment obtain the transmitting time Tm1 of this very first time synchronizing signal;

Wherein, the first equipment first default bit of this very first time synchronizing signal in transmission convergence sublayer reads local zone time and obtains this first transmitting time Tm1.

Step 202, the second time of reception Tm2 of the first equipment sends the second time synchronizing signal from the second equipment to this first equipment sends to this second equipment, makes this second equipment obtain the time of reception Tm2 of this second time synchronizing signal;

Wherein, the first equipment second default bit of this second time synchronizing signal in transmission convergence sublayer reads local zone time and obtains this second time of reception Tm2.

In the present embodiment, this first equipment can be local side DSL access and multiplexing device, and this second equipment can be user side DSL modulator-demodulator.This very first time synchronizing signal can be the downstream signal in digital line system; This second time synchronizing signal can be the upward signal in digital line system.

From above-described embodiment, the first equipment is by default bit, reading the transmitting time that local zone time obtains time of reception and the downstream signal of upward signal, and this time of reception and transmitting time are sent to the second equipment; Like this, the clock offset of the local zone time that can make the second equipment read at default bit according to this time of reception and transmitting time and the second equipment in obtaining digital line system, and carry out clock synchronous according to this clock offset, thereby realized the time synchronization problem in the digital line system.

Embodiment 3

The embodiment of the present invention provides a kind of method for synchronizing time, in order further to improve synchronization accuracy, on the basis of embodiment 1,2, transmit and produced time of delay the local zone time read is proofreaied and correct in the first equipment and the second equipment by predetermined upward signal or downstream signal, according to the Time Calculation clock offset after proofreading and correct, thereby can further improve synchronous precision.

Wherein, comprise successively n the module connected when the second equipment:

1) read position that the first local time T s1 ' is corresponding while being i module when the second equipment:

This downstream signal in transmission from clock module, produce first time of delay Δ T1 be specially: the 1st module time of delay to the i module sum time of delay; And utilize first time of delay Δ T1 proofread and correct the first local time T s1 ', comprising: the first local time T s1 ' that will read deduct first time of delay Δ T1; Like this, the time of reception Ts1 that is downstream signal of the time after correction;

2) when the position that the second equipment reads the second local zone time Ts2 ' correspondence be during i module:

Second time of delay Δ T2 be specially: i module time of delay to the 1 module sum time of delay;

And utilize second time of delay Δ T2 proofread and correct the second local zone time Ts2 ' read, comprising: the second local zone time Ts2 ' that will read add second time of delay Δ T2; Like this, the transmitting time Ts2 that is upward signal of the time after correction; Wherein, n is natural number, the natural number that i is 1 to n.

When the first equipment comprises n the module connected successively:

1) when the position of reading the 3rd local zone time Tm1 ' correspondence be during i module:

The 3rd time of delay Δ T3 be specially: i module time of delay to the n module sum time of delay;

And utilize the 3rd time of delay Δ T3 proofread and correct the 3rd local zone time Tm1 ' read, comprising: the 3rd local zone time Tm1 ' that will read and Δ T3 addition the 3rd time of delay; Like this, the transmitting time Tm1 that is downstream signal of the time after correction;

2) when the position of reading the 4th local zone time Tm2 ' correspondence be during i module:

The 4th time of delay Δ T4 be specially: i module time of delay to the n module sum time of delay;

And utilize the 4th time of delay Δ T4 proofread and correct the 4th local zone time Tm2 ' read, comprising: the 4th local zone time Tm2 ' that will read deduct the 4th time of delay Δ T4; Like this, the time of reception Tm2 that is upward signal of the time after correction; Wherein, n is natural number, the natural number that i is 1 to n.

Below to take the first equipment in the digital line system shown in Fig. 3 be Remote Interface Unit CO, the second equipment is subscriber terminal equipment CPE, and it is that example describes that CO includes the relevant convergence sub-layer of host-host protocol (TPS-TC) module, relevant convergence sub-layer (PMS-TC) module of physical medium, relevant (PMD, the PhysicalMedium Dependent) module of physical media, A/D converter and HYBRID bis-or four line converting analogue circuit with CPE.

As shown in Figure 4, the method comprises:

Step 400, the preproduction phase, pre-determine the time delay that in upward signal, downstream signal each composition module in the first equipment and the second equipment, transmission produces, and store this time delay on corresponding equipment;

Wherein, the time delay of modules on the second equipment:

Downstream signal Δ t_cper time of delay that transmission produces in the A/D converter of the second equipment and HYBRID bis-or four line converting analogue circuit, Δ t time of delay produced in the transmission of PMD module ₁', Δ t time of delay that produces in PMS-TC module transmission ₂', Δ t time of delay that produces in the TPS-TC module ₃';

Upward signal Δ t_cpet time of delay that transmission produces in the A/D converter of the second equipment and HYBRID bis-or four line converting analogue circuit, Δ t time of delay produced in the transmission of PMD module ₄', Δ t time of delay that produces in PMS-TC module transmission ₅', Δ t time of delay that produces in the TPS-TC module ₆';

The time delay of modules on the first equipment:

Downstream signal Δ t_cot time of delay that transmission produces in the A/D converter of the first equipment and HYBRID bis-or four line converting analogue circuit, Δ t time of delay produced in the transmission of PMD module ₁, Δ t time of delay that produces in PMS-TC module transmission ₂, Δ t time of delay that produces in the TPS-TC module ₃;

Upward signal Δ t_cor time of delay that transmission produces in the A/D converter of the first equipment and HYBRID bis-or four line converting analogue circuit, Δ t time of delay produced in the transmission of PMD module ₄, Δ t time of delay that produces in PMS-TC module transmission ₅, Δ t time of delay that produces in the TPS-TC module ₆.

In the present embodiment, time of delay Δ t_cper, Δ t ₁', Δ t ₂', Δ t ₃'; Δ t_cpet, Δ t ₄', Δ t ₅', Δ t ₆'; And Δ t, _ cot, Δ t ₁, Δ t ₂, Δ t ₃; Δ t_cor, Δ t ₄, Δ t ₅, Δ t ₆can adopt existing any mode to obtain;

For example, can be obtained the time of delay produced on analog circuit in Δ t_cper, Δ t_cpet, Δ t_cor and Δ t_cot by test instrumentation, calculating or emulation; A/D converter can obtain in advance by user's manual or the producer of chip;

Time of delay Δ t ₁', Δ t ₂', Δ t ₃', Δ t ₄', Δ t ₅', Δ t ₆'; Δ t ₁, Δ t ₂, Δ t ₃, Δ t ₄, Δ t ₅, Δ t ₆can obtain by modes such as emulation, calculating or measurements;

For example, the circuit of this PMD module comprises signal procesing in time domain circuit, frequency-region signal treatment circuit and sequential logic change-over circuit, can pass through digital circuit simulation or Meter Test, and digital processing circuit also will obtain Δ t through mathematical computations ₁', Δ t ₄', Δ t ₁, Δ t ₄; This PMS-TC module and TPS-TC module comprise RS coding/decoding module, de-interleaving interleaving block, protocol conversion circuitry and other sequential logical circuits, and also can determine Δ t by means such as logical simulations its time of delay ₂', Δ t ₃', Δ t ₅', Δ t ₆', Δ t ₂, Δ t ₃, Δ t ₅, Δ t ₆.

Step 401, the first equipment sends very first time synchronizing signal to the second equipment.

Step 402, the second equipment receives the very first time synchronizing signal that the first equipment sends, and in transmission convergence sublayer, first of this very first time synchronizing signal the default bit reads the first local time T s1 '.

Step 403, proofreaied and correct the first local time T s1 ' read, and the first local zone time after correction is the time of reception Ts1 of very first time synchronizing signal;

In the present embodiment, the position in can the second equipment corresponding when reading the first local time T s1 ' is proofreaied and correct the first local time T s1 '; Wherein, at first when reading the first local time T s1 ' this very first time synchronizing signal of location positioning in corresponding the second equipment in the second equipment, transmit produced first time of delay Δ T1; Then utilize this first delay Δ T1 time to proofread and correct this first local time T s1 ';

In the present embodiment, determine in the following way time of delay:

1) when the position of reading the second equipment that the first local time T s1 ' is corresponding is the TPS-TC module, can determine first time of delay Δ T1=Δ t ₃'+Δ t ₂'+Δ t ₁'+Δ t_cper;

2) when the position of reading the second equipment that the first local time T s1 ' is corresponding is the PMS-TC module, can determine first time of delay Δ T1=Δ t ₂'+Δ t ₁'+Δ t_cper;

3) when the position of reading the second equipment that the first local time T s1 ' is corresponding is the PMD module, can determine first time of delay Δ T1=Δ t ₁'+Δ t_cper;

4) when the position of reading the second equipment that the first local time T s1 ' is corresponding is A/D converter and HYBRID bis-or four line converting analogue circuit, can determine first time of delay Δ T1=Δ t_cper.

After determining the first time of delay Δ T1, can the first local time T s1 ' read be proofreaied and correct, obtain the time of reception Ts1=Ts1 ' of downstream signal-Δ T1.

Step 404, the first equipment is when transmission very first time synchronizing signal, and in transmission convergence sublayer, first of this very first time synchronizing signal the default bit reads the 3rd local zone time Tm1 '.

Step 405, the first equipment is proofreaied and correct the 3rd local zone time Tm1 ' read, and the 3rd local zone time after correction is the transmitting time Tm1 of very first time synchronizing signal;

In the present embodiment, the first equipment is proofreaied and correct adopted mode and the second equipment class seemingly to the 3rd local zone time Tm1 ' read.At first according to read this very first time synchronizing signal of location positioning in the first equipment corresponding to the 3rd local zone time Tm1 ' time in the first equipment, transmit produced the 3rd time of delay Δ T3; Then utilize the 3rd time of delay Δ T3 proofread and correct the 3rd local zone time Tm1 ';

In the present embodiment, determine in the following way time of delay:

1) when the position of the first equipment that reads the 3rd local zone time Tm1 ' correspondence is the TPS-TC module, can determine the 3rd time of delay Δ T3=Δ t ₃+ Δ t ₂+ Δ t ₁+ Δ t_cot;

2) when the position of the first equipment that reads the 3rd local zone time Tm1 ' correspondence is the PMS-TC module, can determine the 3rd time of delay Δ T3=Δ t ₂+ Δ t ₁+ Δ t_cot;

3) when the position of the first equipment that reads the 3rd local zone time Tm1 ' correspondence is the PMD module, can determine the 3rd time of delay Δ T3=Δ t ₁+ Δ t_cot;

4) when the position of the first equipment that reads the 3rd local zone time Tm1 ' correspondence is A/D converter and HYBRID bis-or four line converting analogue circuit, can determine the 3rd time of delay Δ T3=Δ t_cot.

After determining the 3rd time of delay Δ T3, can the 3rd local zone time Tm1 ' read be proofreaied and correct, obtain the transmitting time Tm1=Tm1 ' of downstream signal+Δ T3.

Step 406, the 3rd time synchronizing signal that the first equipment will comprise the transmitting time Tm1 of very first time synchronizing signal sends to the second equipment.

Step 407, the second equipment receives the 3rd time synchronizing signal, therefrom obtains the transmitting time Tm1 of very first time synchronizing signal.

Step 408, the second equipment sends the second time synchronizing signal to the first equipment.

Step 409, the second equipment second default bit of this second time synchronizing signal in transmission convergence sublayer reads the second local zone time Ts2 '.

Step 410, the second equipment is proofreaied and correct the second local zone time Ts2 ' read, and the time after correction is the transmitting time Ts2 of upward signal;

In the present embodiment, that the second local zone time Ts2 ' read is proofreaied and correct to adopted mode is similar to the above for the second equipment.At first according to read this second time synchronizing signal of location positioning in the second equipment corresponding to second local zone time Ts2 ' time in the second equipment, transmit produced second time of delay Δ T2; Then utilize second time of delay Δ T2 proofread and correct this second local zone time Ts2 ';

In the present embodiment, determine in the following way time of delay:

1) when the position of the second equipment that reads the second local zone time Ts2 ' correspondence is the TPS-TC module, can determine second time of delay Δ T2=Δ t ₆'+Δ t ₅'+Δ t ₄'+Δ t_cpet;

2) when the position of the second equipment that reads the second local zone time Ts2 ' correspondence is the PMS-TC module, can determine second time of delay Δ T2=Δ t ₅'+Δ t ₄'+Δ t_cpet;

3) when the position of the second equipment that reads the second local zone time Ts2 ' correspondence is the PMD module, can determine second time of delay Δ T2=Δ t ₄'+Δ t_cpet;

4) when the position of the second equipment that reads the second local zone time Ts2 ' correspondence is A/D converter and HYBRID bis-or four line converting analogue circuit, can determine second time of delay Δ T2=Δ t_cpet.

After determining the second time of delay Δ T2, can the second local zone time Ts2 ' read be proofreaied and correct, obtain the time of reception Ts2=Ts2 ' of downstream signal+Δ T2.

Step 411, after the first equipment receives the second time synchronizing signal of the second equipment transmission, the first equipment second default bit of this second time synchronizing signal in transmission convergence sublayer reads the 4th local zone time Tm2 '.

Step 412, the first equipment is proofreaied and correct the 4th local zone time Tm2 ' read, and the 4th local zone time after correction is the time of reception Tm2 of the second time synchronizing signal;

In the present embodiment, that the 4th local zone time Tm2 ' read is proofreaied and correct to adopted mode is similar to the above for the first equipment.At first according to read this second time synchronizing signal of location positioning in the first equipment corresponding to the 4th local zone time Tm2 ' time in the first equipment, transmit produced the 4th time of delay Δ T4; Then utilize the 4th time of delay Δ T4 proofread and correct the 4th local zone time Tm2 ';

In the present embodiment, determine in the following way time of delay:

1) when the position of the first equipment that reads the 4th local zone time Tm2 ' correspondence is the TPS-TC module, can determine the 4th time of delay Δ T4=Δ t ₆+ Δ t ₅+ Δ t ₄+ Δ t_cor;

2) when the position of the first equipment that reads the 4th local zone time Tm1 ' correspondence is the PMS-TC module, can determine the 4th time of delay Δ T4=Δ t ₅+ Δ t ₄+ Δ t_cor;

3) when the position of the first equipment that reads the 4th local zone time Tm1 ' correspondence is the PMD module, can determine the 4th time of delay Δ T4=Δ t ₄+ Δ t_cor;

4) when the position of the first equipment that reads the 4th local zone time Tm1 ' correspondence is A/D converter and HYBRID bis-or four line converting analogue circuit, can determine the 4th time of delay Δ T4=Δ t_cor.

After determining the 4th time of delay Δ T4, can the 4th local zone time Tm2 ' read be proofreaied and correct, obtain the second time synchronizing signal, i.e. the transmitting time Tm2=Tm2 ' of upward signal-Δ T4.

Step 413, the 4th time synchronizing signal that the first equipment will comprise the 4th local zone time Tm2 after correction sends to the second equipment.

Step 414, the second equipment obtains the time of reception Tm2 of this second time synchronizing signal from the 4th time synchronizing signal.

Step 415, the second equipment is according to transmitting time Tm1 and the transmitting time Ts2 of time of reception Ts1 and this second time synchronizing signal and the clock offset between time of reception Tm2 calculating and this first equipment of the very first time synchronizing signal of obtaining;

In the present embodiment, this downstream signal can be expressed as Δ t0_down in the time of delay of communication line transmission, and this upward signal is expressed as Δ t0_up in the time of delay of communication line transmission, and like this, clock offset offset can adopt following formula to calculate:

Offset＝Ts1-Tm1-Δt0_down；

Offset＝Ts2-Tm2+Δt0_up；

For example, generally at Very-high-speed Digital Subscriber Line road (VDSL, Very High Speed DSL) during the frequency spectrum without the USO frequency range arranges, downstream signal the time of delay of communication line transmission Δ t0_down and upward signal the time of delay of communication line transmission Δ t0_up difference generally in 1 microsecond, can think Δ t0_down=Δ t0_up.In this case, adjust COEFFICIENT K=1, like this, the formula table that calculates clock offset is shown; Offset=(Ts1+Ts2-Tm1-Tm2)/2.

But, for Asymmetrical Digital Subscriber Line (ADSL, Asymmetrical DigitalSubscriber Loop) the frequency spectrum setting such as 1/2/2+, the difference of Δ t0_down and Δ t0_up is larger, if think Δ t0_down=Δ t0_up, the clock offset calculated can not meet the needs of mobile carrying.Like this, the relation table between Δ t0_down and Δ t0_up can be shown to Δ t0_down=K* Δ t0_up, wherein, K is for adjusting coefficient.In this case, clock offset can adopt following formula to calculate;

Offset＝(Ts1+K*Ts2-Tm1-K*Tm2)/(K+1)；

The model actual measurement of the communication line that wherein, K can adopt according to telecommunication bureau obtains or simulation calculation obtains; Perhaps for the difference of Δ t0_down and Δ t0_up generally in 1 microsecond with interior situation, K=1; For situation about differing greatly signal delay time at each frequency of ADSL uplink band, can adopt average weighted method obtain one comprehensive time of delay value or time of delay of adopting low-limit frequency as comprehensive value time of delay, be worth divided by downstream signal the time of delay on twisted-pair feeder with this, can obtain K.But be not limited to this, also can adopt additive method to obtain and adjust COEFFICIENT K.

Like this, can reject by the way the asymmetric impact on time synchronized time of delay in digital subscriber line, further improve synchronization accuracy.

Step 416, the second equipment is adjusted the clock of this second equipment according to this clock offset, make the time synchronized of this time from clock and the first equipment.

From above-described embodiment, proofreaied and correct and obtained the time after correction by the local zone time that default bit position is read, and can be rejected the asymmetric impact on time synchronized time of delay in digital subscriber line, further improve synchronization accuracy.

In the above-described embodiments, as in step 400, can adopt existing any mode to obtain respectively the time delay in modules in the first equipment and the second equipment, then determine as the case may be corresponding time of delay.Except aforesaid way, preferably, also can directly obtain the time of delay produced in the transmission of PMD module, i.e. Δ t by the counter be arranged in the first equipment or the second equipment in the present embodiment ₁', Δ t ₄', Δ t ₁, Δ t ₄; Perhaps obtain the time of delay that transmission produces in PMD module and PMS-TC module, i.e. Δ t ₁'+Δ t ₂', Δ t ₄'+Δ t ₅', Δ t ₁+ Δ t ₂, Δ t ₄+ Δ t ₅; Perhaps obtain the time of delay that transmission produces in PMS-TC module and TPS-TC module, i.e. Δ t ₂'+Δ t ₃', Δ t ₅'+Δ t ₆', Δ t ₂+ Δ t ₃, Δ t ₅+ Δ t ₆; Perhaps obtain the time of delay that transmission produces in PMD module, PMS-TC module and TPS-TC module, i.e. Δ t ₁'+Δ t ₂'+Δ t ₃', Δ t ₄'+Δ t ₅'+Δ t ₆', Δ t ₁+ Δ t ₂+ Δ t ₃, Δ t ₄+ Δ t ₅+ Δ t ₆.

Therefore, after obtaining above-mentioned time delay by counter, only need to obtain the time of delay that transmission produces in A/D converter and HYBRID bis-or four line converting analogue circuit, can obtain first time of delay Δ T1, second time of delay Δ T2, the 3rd time of delay Δ T3, the 4th time of delay Δ T4.

Below in conjunction with Fig. 5, in the mode that counter is set in local side DSL access and multiplexing device, obtain Δ t ₁+ Δ t ₂+ Δ t ₃for example is elaborated.

As shown in Figure 5, this acquisition process comprises:

Step 501 arranges the first counter in the TPS-TC module of local side DSL access and multiplexing device, in the time domain buffering area that approaches A/D converter of PMD module, the second counter is set;

Wherein, the position of the first counter and the second counter is any, for example, also the first counter can be arranged in the PMS-TC module.

Step 502, this first counter and the second counter start counting, and wherein, the first counter is identical with the count frequency of the second counter;

In the present embodiment, for example, the count frequency of the first counter and the second counter can be 10MHz.

Step 503, record the value of the first counter and the second counter;

In the present embodiment, when the second rolling counters forward arrives predetermined bit number, record the value Count1 of the first counter; And, when the sign-on carried when bit corresponding to this predetermined bit number sends downstream signal, record the value Count2 of the second counter;

Wherein, this predetermined bit number can be 1000 times of K byte of a RS, is expressed as: Bits=8*K*1000; Wherein, the byte number that K is the RS code word;

In addition, the symbol that the bit that this predetermined bit number is corresponding carries can be expressed as with formula:

[Bits+Bits*(8*R)/(8*K)]/L0；

Wherein, Bits is predetermined bit number Bits=8*K*1000, the redundancy bytes that R is the RS code word, and L0 is the total number of bits order that a symbol can carry.

For example, if the value of [Bits+Bits* (8*R)/(8*K)]/L0 is 0, can determine this bit that has been the 1st symbols carry; If value is 1, this bit of can having determined the 2nd symbols carry.

Step 504, calculate according to the value Count1 of the first counter recorded and Count2 value and the count frequency of the second counter the time of delay that signal transmits at local side DSL access and multiplexing device.

In the present embodiment, when count frequency is 10MHz, signal can be expressed as in the time of delay of local side DSL access and multiplexing device transmission:

Σ_{i = 1}^{3} {Δt}_{i} = (Count 2 - Count 1) * 0.1

Microsecond.

Said process is only example for take the mode that counter is set in local side DSL access and multiplexing device, illustrates and how to obtain time of delay

Σ_{i = 1}^{3} {Δt}_{i} = {Δt}_{1} + {Δt}_{2} + {Δt}_{3}

Process, by similar method, can obtain other needed time of delay.

Wherein, as shown in Figure 6, in obtaining digital subscriber line, downstream signal, by the Δ T3 or the time of delay of upward signal by the transmission of user side dsl device during Δ T2 time of delay of local side DSL access and multiplexing device transmission, can adopt above-mentioned processing procedure, repeats no more herein.

As shown in Figure 7, in obtaining digital subscriber line, downstream signal is by the Δ T1 or the time of delay of upward signal by the transmission of local side DSL access and multiplexing device during Δ T4 time of delay of user side dsl device transmission, can adopt with step 501 to the similar processing procedure of step 504:

At first, the 3rd counter and four-counter can be set, described similar with step 501;

Secondly, the 3rd counter and four-counter start counting, and the 3rd counter can be identical with the count frequency of four-counter;

Again, record the value of the 3rd counter and four-counter; As described in step 503, wherein, the symbol that the bit that predetermined bit number is corresponding carries can be expressed as with formula:

{(Bits+Bits/(8*K)*(8*R)-8*(I-1)*(D-1)}/L0；

Wherein, Bits is described predetermined bit number, the redundancy bytes that R is the RS code word, and L0 is the total number of bits order that a symbol can carry; I is the interleaving block size, and D is interleave depth.

For example, if the value of { (Bits+Bits/ (8*K) * (8*R)-8* (I-1) * (D-1) }/L0 is 0, can determine this bit that has been the 1st symbols carry; If value is 1, this bit of can having determined the 2nd symbols carry.

Finally, according to value Count3 and the Count4 value of four-counter and time of delay that count frequency can calculate signal of the 3rd counter of record.

Obtain the method for time of delay by the above-mentioned mode that counter is set, can obtain in advance the time of delay of signal in digital subscriber line, eliminate the impact of up-downgoing difference time of delay on time synchronized, further improve the precision of time synchronized.

In the above-mentioned mode that counter is set is obtained the method for time of delay, it is only embodiment that two counters are set.In addition, also can a counter be set in the first equipment and the second equipment, when predetermined bit number, this counter starts counting, when the sign-on carried when bit corresponding to this predetermined bit number sends downstream signal, record the value of this counter, thereby obtain time of delay.But be not limited to this, can determine the embodiment of obtaining time of delay according to actual conditions.

From above-described embodiment, by the first equipment and the second equipment, the default bit of uplink and downlink signals in transmission convergence sublayer reads local zone time, make the second equipment obtain the transmitting-receiving time of uplink and downlink signals in digital line system, and, according to the Time Calculation clock offset obtained, can realize the time synchronized in digital line system; Obtain time of delay by the mode that counter is set, can eliminate the impact of up-downgoing difference time of delay on time synchronized in digital subscriber line, further improve the precision of time synchronized.

Embodiment 4

The embodiment of the present invention provides a kind of dsl device, and as shown in Figure 8, this dsl device is user side DSL modulator-demodulator, comprising: time acquisition unit 801, side-play amount computing unit 802 and time adjustment unit 803;

Wherein, this time acquisition unit 801 sends the first transmitting time Tm1 of very first time synchronizing signal and this user side DSL modulator-demodulator to this user side DSL modulator-demodulator and receives the first time of reception Ts1 of this very first time synchronizing signal and obtain this user side DSL modulator-demodulator and send the second transmitting time Ts2 of the second time synchronizing signal and the second time of reception Tm2 that this local side DSL access and multiplexing device receives this second time synchronizing signal to local side DSL access and multiplexing device for obtaining local side DSL access and multiplexing device;

This side-play amount computing unit 802 calculates the clock offset between this user side DSL modulator-demodulator and this local side DSL access and multiplexing device for the first transmitting time Tm1 of obtaining according to this time acquisition unit 801 and the first time of reception Ts1 and the second transmitting time Ts2 and the second time of reception Tm2;

This time adjustment unit 803 is adjusted the time of this user side DSL modulator-demodulator for the clock offset obtained according to this side-play amount computing unit 802;

In the present embodiment, this very first time synchronizing signal can be the downstream signal in digital line system; This second time synchronizing signal can be the upward signal in digital line system.

From above-described embodiment, by local side DSL access and multiplexing device and user side DSL modulator-demodulator, the default bit of uplink and downlink signals in transmission convergence sublayer reads local zone time, make user side DSL modulator-demodulator obtain the transmitting-receiving time of uplink and downlink signals in digital line system, and according to the Time Calculation clock offset obtained, thereby realized the time synchronization problem in the digital line system.

Embodiment 5

The embodiment of the present invention provides a kind of dsl device, and this dsl device is user side DSL modulator-demodulator, comprising: time acquisition unit 801, side-play amount computing unit 802 and time adjustment unit 803, as described in Example 4;

As shown in Figure 9, this time acquisition unit 801 comprises: the first receiving element 901, the first acquiring unit 902, the first transmitting element 903, second acquisition unit 904, the second receiving element 905, the 3rd acquiring unit 906, the 3rd receiving element 907 and the 4th acquiring unit 908;

Wherein, the very first time synchronizing signal that this first receiving element 901 sends for receiving local side DSL access and multiplexing device; The first default bit of this first acquiring unit 902 very first time synchronizing signal that this first receiving element 901 receives in transmission convergence sublayer reads the first local time T s1 ', to obtain the first time of reception Ts1;

This first transmitting element 903 is for sending the second time synchronizing signal to local side DSL access and multiplexing device; This second acquisition unit 904 reads the second local zone time Ts2 ' for the second default bit of the second time synchronizing signal in these first transmitting element, 903 transmissions of transmission convergence sublayer, to obtain the second transmitting time Ts2;

The 3rd time synchronizing signal that this second receiving element 905 sends for receiving local side DSL access and multiplexing device; The 3rd acquiring unit 906 obtains the first transmitting time Tm1 for the 3rd time synchronizing signal received from this second receiving element 905; This first transmitting time Tm1 is local side DSL access and multiplexing device the 3rd local zone time Tm1 ' that the first default bit of very first time synchronizing signal reads in transmission convergence sublayer; Be perhaps local side DSL access and multiplexing device the 3rd local zone time Tm1 ' that the first default bit of very first time synchronizing signal reads in transmission convergence sublayer, and the 3rd local zone time Tm1 ' proofreaied and correct the time of rear acquisition;

The 4th time synchronizing signal that the 3rd receiving element 907 sends for receiving local side DSL access and multiplexing device; The 4th acquiring unit 908 obtains the second time of reception Tm2 for the 4th time synchronizing signal received from the 3rd receiving element 907; This second time of reception Tm2 is local side DSL access and multiplexing device the 4th local zone time Tm2 ' that the second default bit of the second time synchronizing signal reads in transmission convergence sublayer; Be perhaps local side DSL access and multiplexing device the 4th local zone time Tm2 ' that the second default bit of the second time synchronizing signal reads in transmission convergence sublayer, and the 4th local zone time Tm2 ' proofreaied and correct the time of rear acquisition.

In the present embodiment, this first acquiring unit 902 also can be proofreaied and correct this first local time T s1 ' after reading the first local time T s1 ', further improves the precision of time synchronized.Therefore,

As shown in figure 10, this first acquiring unit 902 specifically can comprise: the first reading unit 1001, the first determining unit 1002 and the first correcting unit 1003;

Wherein, this first reading unit 1001 reads the first local time T s1 ' for the first default bit of the very first time synchronizing signal in these first receiving element, 901 receptions of transmission convergence sublayer;

This first determining unit 1002 for determine very first time synchronizing signal user side DSL modulator-demodulator transmit produced first time of delay Δ T1;

This first correcting unit 1003 for utilize that this first determining unit 1002 determines first time of delay Δ T1 proofread and correct the first local time T s1 ' that this first reading unit 1001 reads; The first local zone time after correction is the first time of reception Ts1.

In the present embodiment, this second acquisition unit 904 also can be after reading the second local zone time Ts2 ', and to this second local zone time, Ts2 ' is proofreaied and correct, and further improves the precision of time synchronized.Therefore,

As shown in figure 11, this second acquisition unit 904 specifically can comprise: the second reading unit 1101, the second determining unit 1102 and the second correcting unit 1103;

Wherein, this second reading unit 1101 reads the second local zone time Ts2 ' for the second default bit of the second time synchronizing signal in these first transmitting element, 903 transmissions of transmission convergence sublayer;

This second determining unit 1102 for determine the second time synchronizing signal user side DSL modulator-demodulator transmit produced second time of delay Δ T2;

This second correcting unit 1103 for utilize that this second determining unit 1102 determines second time of delay Δ T2 proofread and correct the second local zone time Ts2 ' that the second reading unit 1101 reads; The second local zone time after correction is the second transmitting time Ts2.

In the present embodiment, user side DSL modulator-demodulator can comprise n the module connected successively;

Like this, when this first reading unit 1001 reads position that the first local time T s1 ' is corresponding, be during i module: this first determining unit 1002 definite first time of delay Δ T1 be specially: the 1st module time of delay to the i module sum time of delay; And this first correcting unit 1003 utilize first time of delay Δ T1 proofread and correct the first local time T s1 ', comprising: the first local time T s1 ' that will read deduct first time of delay Δ T1;

When the position that this second reading unit 1101 reads the second local zone time Ts2 ' correspondence is during i module: this second determining unit 1102 determine second time of delay Δ T2 be specially: i module time of delay to the 1 module sum time of delay; And this second correcting unit 1103 utilize second time of delay Δ T2 proofread and correct the second local zone time Ts2 ', comprising: the second local zone time Ts2 ' that will read add second time of delay Δ T2;

Wherein, n is natural number, the natural number that i is 1 to n.

Further, n the module connected successively that user side DSL modulator-demodulator comprises can be: the analog circuit, A/D converter, PMD module, PMS-TC module and the TPS-TC module that connect successively; This time synchronism apparatus comprises: first time of delay the acquiring unit (not shown);

Wherein, this first time of delay acquiring unit can by be arranged on that counter in user side DSL modulator-demodulator obtains the PMD module to PMS-TC module or PMD module to the TPS-TC module or the PMS-TC module to sum time of delay of TPS-TC module.Concrete steps can, as step 501 in embodiment 3 to as described in step 504, repeat no more herein.

In the present embodiment, when this side-play amount computing unit 802 calculates clock offset, concrete formula can be expressed as;

Offset=(Ts1+K*Ts2-Tm1-K*Tm2)/(K+1); Wherein, K is for adjusting coefficient.

From above-described embodiment, read local zone time by local side DSL access and multiplexing device and user side DSL modulator-demodulator at the default bit of uplink and downlink signals, make user side DSL modulator-demodulator obtain the transmitting-receiving time of uplink and downlink signals in digital line system, and, according to the Time Calculation clock offset obtained, can realize the time synchronized in digital line system; Obtain time of delay by the mode that counter is set, can eliminate the impact of up-downgoing difference time of delay on time synchronized in digital subscriber line, further improve the precision of time synchronized.

Embodiment 6

The embodiment of the present invention provides a kind of local side DSL access and multiplexing device, and as shown in figure 12, this local side DSL access and multiplexing device comprises: the first processing unit 1201 and the second processing unit 1202;

Wherein, this first processing unit 1201 sends to this user side DSL modulator-demodulator for the first transmitting time Tm1 that this local side DSL access and multiplexing device is sent to very first time synchronizing signal to user side DSL modulator-demodulator, makes this user side DSL modulator-demodulator obtain the transmitting time Tm1 of very first time synchronizing signal;

This second processing unit 1202 sends to user side DSL modulator-demodulator for the second time of reception Tm2 of the second time synchronizing signal that user side DSL modulator-demodulator is sent to this local side DSL access and multiplexing device, makes this user side DSL modulator-demodulator obtain the time of reception Tm2 of the second time synchronizing signal.

Wherein, this local side DSL access and multiplexing device first default bit of very first time synchronizing signal in transmission convergence sublayer reads local zone time and obtains the first transmitting time Tm1; In transmission convergence sublayer, second of the second time synchronizing signal the default bit reads local zone time and obtains the second time of reception Tm2.

From above-described embodiment, local side DSL access and multiplexing device is by default bit, reading the transmitting time that local zone time obtains time of reception and the downstream signal of upward signal, and this time of reception and transmitting time are sent to user side DSL modulator-demodulator; Like this, can make the clock offset of user side DSL modulator-demodulator in obtaining digital line system according to this time of reception and transmitting time and the local zone time that reads at default bit, and carry out clock synchronous according to this clock offset, thereby realized the time synchronization problem in the digital line system.

Embodiment 7

The embodiment of the present invention provides a kind of local side DSL access and multiplexing device, and this local side DSL access and multiplexing device comprises: the first processing unit 1201 and the second processing unit 1202, as described in Example 6;

As shown in figure 13, this first processing unit 1201 comprises: the second transmitting element 1301, the 5th acquiring unit 1302 and the 3rd transmitting element 1303;

Wherein, this second transmitting element 1301 is for sending very first time synchronizing signal to user side DSL modulator-demodulator; The 5th acquiring unit 1302 reads the 3rd local zone time Tm1 ' for the first default bit of the very first time synchronizing signal in these second transmitting element, 1301 transmissions of transmission convergence sublayer, to obtain the first transmitting time Tm1 of very first time synchronizing signal; The 3rd transmitting element 1303 is sent to user side DSL modulator-demodulator for the 3rd time synchronizing signal that will comprise this first transmitting time Tm1.

In the present embodiment, the 5th acquiring unit 1302 also can be proofreaied and correct the 3rd local zone time Tm1 ' after reading the 3rd local zone time Tm1 ', further improves the precision of time synchronized.Therefore,

As shown in figure 14, the 5th acquiring unit 1302 specifically can comprise: third reading is got unit 1401, the 3rd determining unit 1402 and the 3rd correcting unit 1403;

Wherein, this third reading is got unit 1401 and is read the 3rd local zone time Tm1 ' for the first default bit of the very first time synchronizing signal that sends at this second transmitting element of transmission convergence sublayer 1301;

The 3rd determining unit 1402 for determine very first time synchronizing signal local side DSL access and multiplexing device transmit produced the 3rd time of delay Δ T3;

The 3rd correcting unit 1403 for utilize that the 3rd determining unit 1402 determines the 3rd time of delay Δ T3 proofread and correct this third reading and get the 3rd local zone time Tm1 ' that unit 1401 reads; The 3rd local zone time after correction is the first transmitting time Tm1.

As shown in figure 15, this second processing unit 1202 comprises: the 4th receiving element 1501, the 6th acquiring unit 1502 and the 4th transmitting element 1503;

Wherein, the second time synchronizing signal that the 4th receiving element 1501 sends to local side DSL access and multiplexing device for receiving user side DSL modulator-demodulator; The 6th acquiring unit 1502 reads the 4th local zone time Tm2 ' for the second default bit of the second time synchronizing signal in transmission convergence sublayer the 4th receiving element 1501 receptions, to obtain the second time of reception Tm2 of the second time synchronizing signal; The 4th transmitting element 1503 is sent to user side DSL modulator-demodulator for the 4th time synchronizing signal that will comprise the second time of reception Tm2.

In the present embodiment, the 6th acquiring unit 1502 also can be proofreaied and correct the 4th local zone time Tm2 ' after reading the 4th local zone time Tm2 ', further improves the precision of time synchronized.Therefore,

As shown in figure 16, the 6th acquiring unit 1502 specifically can comprise: the 4th reading unit 1601, the 4th determining unit 1602 and the 4th correcting unit 1603;

Wherein, the 4th reading unit 1601 reads the 4th local zone time Tm2 ' for the second default bit of the second time synchronizing signal in transmission convergence sublayer the 4th receiving element 1501 receptions;

The 4th determining unit 1602 for determine the second time synchronizing signal local side DSL access and multiplexing device transmit produced the 4th time of delay Δ T4;

The 4th correcting unit 1603 for utilize that the 4th determining unit 1602 determines the 4th time of delay Δ T4 proofread and correct the 4th local zone time Tm2 ' that the 4th reading unit 1601 reads; The 4th local zone time after correction is the second time of reception Tm2.

In the present embodiment, this local side DSL access and multiplexing device comprises n the module connected successively;

Like this, getting the position of reading the 3rd local zone time Tm1 ' correspondence in unit 1401 when this third reading is during i module: the 3rd determining unit 1402 determine the 3rd time of delay Δ T3 be specially: i module time of delay to the n module sum time of delay; And the 3rd correcting unit 1403 utilize the 3rd time of delay Δ T3 proofread and correct the 3rd local zone time Tm1 ' read, comprising: the 3rd local zone time Tm1 ' that will read and Δ T3 addition the 3rd time of delay;

When the position that the 4th reading unit 1601 reads the 4th local zone time Tm2 ' correspondence is during i module: the 4th determining unit 1602 determine the 4th time of delay Δ T4 be specially: i module time of delay to the n module sum time of delay; And the 4th correcting unit 1603 utilize the 4th time of delay Δ T4 proofread and correct the 4th local zone time Tm2 ' read, comprising: the 4th local zone time Tm2 ' that will read deduct the 4th time of delay Δ T4;

Wherein, n is natural number, the natural number that i is 1 to n.

In the present embodiment, n the module connected successively that local side DSL access and multiplexing device comprises can be: the TPS-TC module, PMS-TC module, PMD module, A/D converter and the analog circuit that connect successively; This time synchronism apparatus comprises: second time of delay the acquiring unit (not shown);

Wherein, this second time of delay acquiring unit can by be arranged on that counter in local side DSL access and multiplexing device obtains the TPS-TC module to PMS-TC module or TPS-TC module to the PMD module or the PMS-TC module to sum time of delay of PMD module.Concrete steps can, as step 501 in embodiment 3 to as described in step 504, repeat no more herein.

Embodiment 8

The embodiment of the present invention provides a kind of wide-band cut-in network system, as shown in figure 17, this wide-band cut-in network system comprises the transmission line between user side DSL modulator-demodulator 1701, local side DSL access and multiplexing device 1702 and local side DSL access and multiplexing device 1702 and user side DSL modulator-demodulator 1701;

Wherein, this user side DSL modulator-demodulator 1701 can comprise the dsl device described in embodiment 4 or 5, and this local side DSL access and multiplexing device 1702 can comprise the local side DSL access and multiplexing device described in embodiment 6 or 7; Repeat no more herein.

From above-described embodiment, read local zone time by local side DSL access and multiplexing device and user side DSL modulator-demodulator at the default bit of uplink and downlink signals, make user side DSL modulator-demodulator obtain the transmitting-receiving time of uplink and downlink signals in digital line system, and, according to the Time Calculation clock offset obtained, can realize the time synchronized in digital line system.

The professional can also further recognize, unit and the algorithm steps of each example of describing in conjunction with embodiment disclosed herein, can realize with electronic hardware, computer software or the combination of the two, for the interchangeability of hardware and software clearly is described, composition and the step of each example described according to function in the above description in general manner.These functions are carried out with hardware or software mode actually, depend on application-specific and the design constraint of technical scheme.The professional and technical personnel can specifically should be used for realizing described function with distinct methods to each, but this realization should not thought and exceeds scope of the present invention.

The software module that the method for describing in conjunction with embodiment disclosed herein or the step of algorithm can use hardware, processor to carry out, or the combination of the two is implemented.Software module can be placed in the storage medium of any other form known in random asccess memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable ROM, register, hard disk, moveable magnetic disc, CD-ROM or technical field.

Above-described embodiment; purpose of the present invention, technical scheme and beneficial effect are further described; institute is understood that; the foregoing is only the specific embodiment of the present invention; the protection range be not intended to limit the present invention; within the spirit and principles in the present invention all, any modification of making, be equal to replacement, improvement etc., within all should being included in protection scope of the present invention.

Claims

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

The second equipment obtains the first equipment and sends the first transmitting time Tm1 of very first time synchronizing signal and the first time of reception Ts1 that described the second equipment receives described very first time synchronizing signal and second equipment that obtains to the second equipment and send the second transmitting time Ts2 of the second time synchronizing signal and the second time of reception Tm2 that described the first equipment receives described the second time synchronizing signal to the first equipment;

Calculate the clock offset between described the second equipment and described the first equipment according to described the first transmitting time Tm1 and the first time of reception Ts1 and described the second transmitting time Ts2 and the second time of reception Tm2;

Adjust the time of described the second equipment according to described clock offset;

Wherein, described the first equipment is local side DSL access and multiplexing device; Described the second equipment is the user side dsl device;

Wherein, read local zone time at the first default bit of the synchronizing signal of the very first time described in transmission convergence sublayer and obtain described the first transmitting time Tm1 and described the first time of reception Ts1; Read local zone time at the second default bit of the second time synchronizing signal described in transmission convergence sublayer and obtain described the second transmitting time Ts2 and described the second time of reception Tm2;

Wherein, the second equipment receives the very first time synchronizing signal that the first equipment sends, and presets bit in first of the synchronizing signal of the very first time described in transmission convergence sublayer and reads the first local time T s1', to obtain described the first time of reception Ts1;

The second equipment receives the 3rd time synchronizing signal that described the first equipment sends, and obtains described the first transmitting time Tm1 from described the 3rd time synchronizing signal; Described the first transmitting time Tm1 is that described the first equipment presets in described first of the synchronizing signal of the very first time described in transmission convergence sublayer the 3rd local zone time Tm1' that bit reads; Perhaps for described the first equipment, in described first of the synchronizing signal of the very first time described in transmission convergence sublayer, preset the 3rd local zone time Tm1' that bit reads, and described the 3rd local zone time Tm1' is proofreaied and correct the time of rear acquisition;

The second equipment sends the second time synchronizing signal to the first equipment, presets bit at second of the second time synchronizing signal described in transmission convergence sublayer and reads the second local zone time Ts2', to obtain described the second transmitting time Ts2;

The second equipment receives the 4th time synchronizing signal that the first equipment sends, and obtains described the second time of reception Tm2 from described the 4th time synchronizing signal; Described the second time of reception Tm2 is that described the first equipment presets at described second of the second time synchronizing signal described in transmission convergence sublayer the 4th local zone time Tm2' that bit reads; Perhaps for described the first equipment, at described second of the second time synchronizing signal described in transmission convergence sublayer, preset the 4th local zone time Tm2' that bit reads, and described the 4th local zone time Tm2' is proofreaied and correct the time of rear acquisition.

2. method for synchronizing time according to claim 1, it is characterized in that, described the second equipment receives the very first time synchronizing signal that the first equipment sends, the first default bit in the synchronizing signal of the very first time described in transmission convergence sublayer reads the first local time T s1', to obtain described the first time of reception Ts1, comprising:

Described the second equipment receives the very first time synchronizing signal that the first equipment sends, and presets bit in first of the synchronizing signal of the very first time described in transmission convergence sublayer and reads the first local time T s1';

Determine described very first time synchronizing signal in described the second equipment, transmit produced first time of delay Δ T1, utilize described first time of delay Δ T1 proofread and correct the described first local time T s1';

The first local zone time after correction is described the first time of reception Ts1.

3. method for synchronizing time according to claim 1, it is characterized in that, described the second equipment sends the second time synchronizing signal to the first equipment, the second default bit at the second time synchronizing signal described in transmission convergence sublayer reads the second local zone time Ts2', to obtain described the second transmitting time Ts2, comprising:

Described the second equipment sends the second time synchronizing signal to the first equipment, presets bit at second of the second time synchronizing signal described in transmission convergence sublayer and reads the second local zone time Ts2';

Determine described the second time synchronizing signal in described the second equipment, transmit produced second time of delay Δ T2, utilize described second time of delay Δ T2 proofread and correct described the second local zone time Ts2';

The second local zone time after correction is described the second transmitting time Ts2.

4. a user side dsl device, is characterized in that, described user side dsl device comprises:

Time acquisition unit, send the first transmitting time Tm1 of very first time synchronizing signal and the first time of reception Ts1 that described user side dsl device receives described very first time synchronizing signal and obtain described user side dsl device to described user side dsl device and send the second transmitting time Ts2 of the second time synchronizing signal and the second time of reception Tm2 that described local side DSL access and multiplexing device receives described the second time synchronizing signal to described local side DSL access and multiplexing device for obtaining local side DSL access and multiplexing device;

The first receiving element, the very first time synchronizing signal sent for receiving described local side DSL access and multiplexing device;

The first acquiring unit, preset bit for first of very first time synchronizing signal described in the transmission convergence sublayer received at described the first receiving element and read the first local time T s1', to obtain described the first time of reception Ts1;

The first transmitting element, for sending the second time synchronizing signal to described local side DSL access and multiplexing device;

Second acquisition unit, preset bit for second of the second time synchronizing signal described in the transmission convergence sublayer sent at described the first transmitting element and read the second local zone time Ts2', to obtain described the second transmitting time Ts2;

The second receiving element, the 3rd time synchronizing signal sent for receiving described local side DSL access and multiplexing device;

The 3rd acquiring unit, obtain described the first transmitting time Tm1 for described the 3rd time synchronizing signal received from described the second receiving element; Described the first transmitting time Tm1 is that described local side DSL access and multiplexing device presets in described first of the synchronizing signal of the very first time described in transmission convergence sublayer the 3rd local zone time Tm1' that bit reads; Perhaps for described local side DSL access and multiplexing device, in described first of the synchronizing signal of the very first time described in transmission convergence sublayer, preset the 3rd local zone time Tm1' that bit reads, and described the 3rd local zone time Tm1' is proofreaied and correct the time of rear acquisition;

The 3rd receiving element, the 4th time synchronizing signal sent for receiving local side DSL access and multiplexing device;

The 4th acquiring unit, obtain described the second time of reception Tm2 for described the 4th time synchronizing signal received from described the 3rd receiving element; Described the second time of reception Tm2 is that described local side DSL access and multiplexing device presets at described second of the second time synchronizing signal described in transmission convergence sublayer the 4th local zone time Tm2' that bit reads; Perhaps for described local side DSL access and multiplexing device, at described second of the second time synchronizing signal described in transmission convergence sublayer, preset the 4th local zone time Tm2' that bit reads, and described the 4th local zone time Tm2' is proofreaied and correct the time of rear acquisition.

5. a local side DSL access and multiplexing device, is characterized in that, described local side DSL access and multiplexing device comprises:

Wherein, read local zone time at the first default bit of the synchronizing signal of the very first time described in transmission convergence sublayer and obtain described the first transmitting time Tm1; Read local zone time at the second default bit of the second time synchronizing signal described in transmission convergence sublayer and obtain described the second time of reception Tm2;

Wherein said the first processing unit comprises:

The second transmitting element, for sending very first time synchronizing signal to described user side dsl device;

The 5th acquiring unit, preset bit for first of the described very first time synchronizing signal from described in transmission convergence sublayer, the second transmitting element sends and read the 3rd local zone time Tm1', to obtain the first transmitting time Tm1 of described very first time synchronizing signal; Perhaps, preset bit for first of the described very first time synchronizing signal described in transmission convergence sublayer, the second transmitting element sends and read the 3rd local zone time Tm1', and the 3rd local zone time Tm1' is proofreaied and correct to described the first transmitting time Tm1 of rear acquisition;

The 3rd transmitting element, be sent to described user side dsl device for the 3rd time synchronizing signal that will comprise described the first transmitting time Tm1;

Wherein said the second processing unit comprises:

The 4th receiving element, the second time synchronizing signal sent to described local side DSL access and multiplexing device for receiving described user side dsl device;

The 6th acquiring unit, preset bit for second of described the second time synchronizing signal from described in transmission convergence sublayer, the 4th receiving element receives and read the 4th local zone time Tm2', to obtain the second time of reception Tm2 of described the second time synchronizing signal; Perhaps, read the 4th local zone time Tm2' for the second default bit of described the second time synchronizing signal described in transmission convergence sublayer, the 4th receiving element receives and the 3rd local zone time Tm2' is proofreaied and correct after obtain described the second time of reception Tm2;

The 4th transmitting element, be sent to described user side dsl device for the 4th time synchronizing signal that will comprise described the second time of reception Tm2.

6. local side DSL access and multiplexing device according to claim 5, it is characterized in that, described the 5th acquiring unit also reads the 3rd local zone time Tm1' for the first default bit of the described very first time synchronizing signal described in transmission convergence sublayer, the second transmitting element sends; Determine described very first time synchronizing signal in described local side DSL access and multiplexing device, transmit produced the 3rd time of delay Δ T3; Utilize described the 3rd time of delay Δ T3 proofread and correct described the 3rd local zone time Tm1'; The 3rd local zone time after correction is described the first transmitting time Tm1.

7. local side DSL access and multiplexing device according to claim 5, it is characterized in that, described the 6th acquiring unit also reads the 4th local zone time Tm2' for the second default bit of described the second time synchronizing signal described in transmission convergence sublayer, the 4th receiving element receives; Determine described the second time synchronizing signal in described local side DSL access and multiplexing device, transmit produced the 4th time of delay Δ T4; Utilize described the 4th time of delay Δ T4 proofread and correct described the 4th local zone time Tm2'; The 4th local zone time after correction is described the second time of reception Tm2.

8. a wide-band cut-in network system, described system comprises the transmission line between local side DSL access and multiplexing device, user side dsl device and described local side DSL access and multiplexing device and user side dsl device; It is characterized in that,

Described user side dsl device comprises dsl device claimed in claim 4; Described local side DSL access and multiplexing device comprises the described local side DSL of any one claim access and multiplexing device of claim 5 to 7.