CN102143571A

CN102143571A - Time synchronization method, DSL equipment and broadband access network system

Info

Publication number: CN102143571A
Application number: CN2010101113418A
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: 2011-08-03
Anticipated expiration: 2030-02-02
Also published as: CN102143571B

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 development of Communication Technique, mobile service is more and more higher to the requirement of time synchronized, has reached the requirement of microsecond level.At present, for the needs that satisfy high precision clock and time synchronized have been developed IEEE 1588 agreements, by calculating time deviation from clock and master clock, will be from the clock synchronization 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 synchronization to the master clock.

But the inventor finds that the defective 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 to transmit with continual symbol one by one, there is not tangible boundary line between symbol and the symbol, be not easy to find synchronous points to carry out time mark, therefore, also there is not concrete method to realize time synchronized at present for this system; In addition,, cause time error bigger, therefore, can not satisfy the needs that move carrying because the up-downgoing delay-time difference of channel is bigger in this system.

Summary of the invention

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

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

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

Calculate clock offset between second equipment and 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 second equipment according to clock offset;

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

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

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

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

The time adjustment unit is used for adjusting according to the described clock offset that described side-play amount computing unit obtains time of described 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 the transmission convergence sublayer and obtain described first transmitting time Tm1 and the described first time of reception Ts1; Read local zone time at the second default bit of second time synchronizing signal described in the transmission convergence sublayer and obtain described second transmitting time Ts2 and the described second time of reception Tm2.

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

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

Second processing unit, be used for described user side dsl device is sent to described user side dsl device to the second time of reception Tm2 of second time synchronizing signal of described local side DSL access and multiplexing device transmission, make described user side dsl device obtain the time of reception Tm2 of described 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 the transmission convergence sublayer and obtain the described first transmitting time Tm1; Read local zone time at the second default bit of second time synchronizing signal described in the transmission convergence sublayer and obtain the described second time of reception Tm2.

The embodiment of the 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 the user side dsl device.

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

Description of drawings

Accompanying drawing described herein is used to provide further understanding of the present invention, constitutes the application's a part, does not constitute 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 invention 1;

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

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

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

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

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

Fig. 7 is that another of the embodiment of the 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 invention 4;

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

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

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

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

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

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

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

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

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

Embodiment

For making the purpose, technical solutions and advantages of the present invention clearer, the embodiment of the invention is described in further detail below in conjunction with accompanying drawing.At this, illustrative examples of the present invention and explanation thereof are used to explain the present invention, but not as a limitation of the invention.

Embodiment 1

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

Step 101, second equipment are obtained first equipment and are sent the first transmitting time Tm1 of 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 second transmitting time Ts2 of second time synchronizing signal and the second time of reception Tm2 that this first equipment receives this second time synchronizing signal to first equipment to second equipment;

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

Step 102, second equipment calculates clock offset between this second equipment and 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, second equipment are 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 the digital line system; This second time synchronizing signal can be the upward signal in the 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) relevant convergence sub-layer 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 with in the digital subscriber line synchronous from clock and master clock.

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).

By the foregoing description as can be known, the default bit of uplink and downlink signals in transmission convergence sublayer reads local zone time by first equipment and second equipment, second equipment that makes obtains the transmitting-receiving time of uplink and downlink signals in the digital line system, and according to the Time Calculation clock offset that obtains, thereby realized the time synchronization problem in the digital line system.

Embodiment 2

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

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

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

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

Wherein, 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 the digital line system; This second time synchronizing signal can be the upward signal in the digital line system.

By the foregoing description as can be known, first equipment is by reading the transmitting time that local zone time obtains the time of reception and the downstream signal of upward signal at default bit, and this time of reception and transmitting time are sent to second equipment; Like this, the local zone time that can make second equipment read at default bit according to this time of reception and transmitting time and second equipment obtains the clock offset in the digital line system, and carry out clock synchronization, thereby realized the time synchronization problem in the digital line system according to this clock offset.

Embodiment 3

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

Wherein, comprise successively n the module that connects when second equipment:

1) when the position that second equipment reads first local zone time Ts1 ' correspondence is i module:

This downstream signal 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 zone time Ts1 ', comprising: the first local zone time Ts1 ' that will read deduct first time of delay Δ T1; Like this, the time after the correction is the time of reception Ts1 of downstream signal;

2) when the position that second equipment reads 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 ' that reads, comprising: the second local zone time Ts2 ' that will read add second time of delay Δ T2; Like this, the time after the correction is the transmitting time Ts2 of upward signal; Wherein, n is a natural number, and i is 1 to n natural number.

Comprise n the module that connects successively when first equipment:

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

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

Below be Remote Interface Unit CO with first equipment in the digital line system shown in Figure 3, 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 two or four line converting analogue circuit with CPE.

As shown in Figure 4, this method comprises:

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

Wherein, the time delay of each module on second equipment:

Downstream signal Δ t_cper time of delay that transmission produces in the A/D converter of second equipment and HYBRID two or four line converting analogue circuit, Δ t time of delay that produces 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 second equipment and HYBRID two or four line converting analogue circuit, Δ t time of delay that produces 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 each module on first equipment:

Downstream signal Δ t_cot time of delay that transmission produces in the A/D converter of first equipment and HYBRID two or four line converting analogue circuit, Δ t time of delay that produces 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 first equipment and HYBRID two or four line converting analogue circuit, Δ t time of delay that produces 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 ₃Δ t_cor, Δ t ₄, Δ t ₅, Δ t ₆Can adopt existing any mode to obtain;

For example, can obtain by test instrumentation, calculating or emulation the time of delay that produces on the analog circuit among Δ t_cper, Δ t_cpet, Δ t_cor and the Δ t_cot; A/D converter can obtain in advance by the 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 time-domain signal treatment 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 ₄This 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, first equipment sends very first time synchronizing signal to second equipment.

Step 402, second equipment receive the very first time synchronizing signal that first equipment sends, and the first default bit that should very first time synchronizing signal in transmission convergence sublayer reads the first local zone time Ts1 '.

Step 403 is proofreaied and correct the first local zone time Ts1 ' that reads, and first local zone time after the correction is the time of reception Ts1 of very first time synchronizing signal;

In the present embodiment, can proofread and correct the first local zone time Ts1 ' according to the position in second equipment that reads first local zone time Ts1 ' time correspondence; Wherein, at first according to read position in second equipment of first local zone time Ts1 ' time correspondence determine this very first time synchronizing signal in second equipment, transmit produced first time of delay Δ T1; Utilize this first delay Δ T1 time to proofread and correct this first local zone time Ts1 ' then;

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

1) when the position of second equipment that reads first local zone time Ts1 ' correspondence 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 second equipment that reads first local zone time Ts1 ' correspondence 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 second equipment that reads first local zone time Ts1 ' correspondence is the PMD module, can determine first time of delay Δ T1=Δ t ₁'+Δ t_cper;

4) when the position of second equipment that reads first local zone time Ts1 ' correspondence is A/D converter and HYBRID two 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 zone time Ts1 ' that read be proofreaied and correct, obtain the time of reception Ts1=Ts1 '-Δ T1 of downstream signal.

Step 404, first equipment is sending the very first time during synchronizing signal, and the first default bit that should very first time synchronizing signal in transmission convergence sublayer reads the 3rd local zone time Tm1 '.

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

In the present embodiment, first equipment is proofreaied and correct the mode that adopted and second equipment class seemingly to the 3rd local zone time Tm1 ' that reads.At first according to read position in first equipment of the 3rd local zone time Tm1 ' time correspondence determine this very first time synchronizing signal in first equipment, transmit produced the 3rd time of delay Δ T3; Utilize then the 3rd time of delay Δ T3 proofread and correct the 3rd local zone time Tm1 ';

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

1) when the position of 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 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 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 first equipment that reads the 3rd local zone time Tm1 ' correspondence is A/D converter and HYBRID two 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 ' that read be proofreaied and correct, obtain the transmitting time Tm1=Tm1 '+Δ T3 of downstream signal.

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

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

Step 408, second equipment sends second time synchronizing signal to 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, second equipment is proofreaied and correct the second local zone time Ts2 ' that reads, and the time after the correction is the transmitting time Ts2 of upward signal;

In the present embodiment, that the second local zone time Ts2 ' that reads is proofreaied and correct the mode that is adopted is similar to the above for second equipment.At first according to read position in second equipment of second local zone time Ts2 ' time correspondence determine this second time synchronizing signal in second equipment, transmit produced second time of delay Δ T2; Utilize then second time of delay Δ T2 proofread and correct this second local zone time Ts2 ';

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

1) when the position of second equipment that reads 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 second equipment that reads 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 second equipment that reads 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 second equipment that reads second local zone time Ts2 ' correspondence is A/D converter and HYBRID two 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 ' that read be proofreaied and correct, obtain the time of reception Ts2=Ts2 '+Δ T2 of downstream signal.

After step 411, first equipment received second time synchronizing signal of second equipment transmission, first equipment, second default bit of this second time synchronizing signal in transmission convergence sublayer read the 4th local zone time Tm2 '.

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

In the present embodiment, that the 4th local zone time Tm2 ' that reads is proofreaied and correct the mode that is adopted is similar to the above for first equipment.At first according to read position in first equipment of the 4th local zone time Tm2 ' time correspondence determine this second time synchronizing signal in first equipment, transmit produced the 4th time of delay Δ T4; Utilize then the 4th time of delay Δ T4 proofread and correct the 4th local zone time Tm2 ';

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

1) when the position of 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 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 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 first equipment that reads the 4th local zone time Tm1 ' correspondence is A/D converter and HYBRID two 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 ' that read be proofreaied and correct, obtain second time synchronizing signal, i.e. the transmitting time Tm2=Tm2 ' of upward signal-Δ T4.

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

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

Step 415, 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 communication line transmission delay time, and this upward signal is expressed as Δ t0_up in the communication line transmission delay time, 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 is provided with, downstream signal communication line transmission delay time Δ t0_down and upward signal in the difference of communication line transmission delay time Δ t0_up generally in 1 microsecond, can think Δ t0_down=Δ t0_up.In this case, adjust COEFFICIENT K=1, like this, the formulate that calculates clock offset is; Offset=(Ts1+Ts2-Tm1-Tm2)/2.

But, for Asymmetrical Digital Subscriber Line (ADSL, Asymmetrical DigitalSubscriber Loop) frequency spectrum setting such as 1/2/2+, the difference of Δ t0_down and Δ t0_up is bigger, if think that Δ t0_down=Δ t0_up, the clock offset that calculates can not satisfy the needs that move carrying.Like this, the relation table between Δ t0_down and the Δ t0_up can be shown 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)；

Wherein, K can obtain or simulation calculation obtains according to the actual measurement of the model of the communication line that telecommunication bureau adopted; 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 weighted-average method obtain one comprehensive time of delay value or time of delay of adopting low-limit frequency as comprehensive value time of delay, divided by the time of delay of downstream signal on twisted-pair feeder, can obtain K with this value.But be not limited thereto, also can adopt additive method to obtain to adjust COEFFICIENT K.

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

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

By the foregoing description as can be known, proofread and correct and obtain time after the correction, and can reject asymmetric influence time of delay in the digital subscriber line, further improve synchronization accuracy time synchronized by the local zone time that default bit position is read.

In the above-described embodiments,, can adopt existing any way to obtain the time delay in each module in first equipment and second equipment respectively, determine corresponding time of delay then as the case may be as in the step 400.Except aforesaid way, preferably, also can directly obtain at the time of delay of PMD module transmission generation, i.e. Δ t in the present embodiment by the counter that is arranged in first equipment or second equipment ₁', Δ t ₄', Δ t ₁, Δ t ₄Perhaps 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 ₅Perhaps 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 ₆Perhaps 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 two 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, obtain Δ t in local side DSL access and multiplexing device in the mode that counter is set ₁+ Δ t ₂+ Δ t ₃For example is elaborated.

As shown in Figure 5, this acquisition process comprises:

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

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

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

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

Step 503 writes down the value of first counter and second counter;

In the present embodiment, when second rolling counters forward during, write down the value Count1 of first counter to predetermined bit number; And when the sign-on that bit carried of this predetermined bit number correspondence sends downstream signal, write down the value Count2 of 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, K is the byte number of RS code word;

In addition, the symbol that bit carried of the bit number correspondence that this is predetermined can be expressed as with formula:

[Bits+Bits*(8*R)/(8*K)]/L0；

Wherein, Bits is predetermined bit number Bits=8*K*1000, and R is the redundancy bytes of 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 is calculated signal in local side DSL access and multiplexing device transmission delay time according to the value Count1 of first counter that writes down and the Count2 value and the count frequency of second counter.

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

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

Microsecond.

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

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, when downstream signal passes through user side dsl device transmission delay time Δ T2 by local side DSL access and multiplexing device transmission delay time Δ T3 or upward signal in obtaining digital subscriber line, can adopt above-mentioned processing procedure, repeat no more herein.

As shown in Figure 7, downstream signal is by user side dsl device transmission delay time Δ T1 or upward signal during by local side DSL access and multiplexing device transmission delay time Δ T4 in obtaining digital subscriber line, 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 begin counting, and the count frequency of the 3rd counter and four-counter can be identical;

Once more, write down the value of the 3rd counter and four-counter; As described in step 503, wherein, the symbol that bit carried of predetermined bit number correspondence 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, and R is the redundancy bytes of 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 an 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.

At last, but according to value Count3 and the Count4 value of four-counter and time of delay of count frequency signal calculated of the 3rd counter of record.

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

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

By the foregoing description as can be known, the default bit of uplink and downlink signals in transmission convergence sublayer reads local zone time by first equipment and second equipment, second equipment that makes obtains the transmitting-receiving time of uplink and downlink signals in the digital line system, and, can realize the time synchronized in the digital line system according to the Time Calculation clock offset that obtains; Obtain time of delay by the mode that counter is set, can eliminate that up-downgoing difference time of delay further improves the precision of time synchronized to the influence of time synchronized in the digital subscriber line.

Embodiment 4

The embodiment of the invention provides a kind of dsl device, and as shown in Figure 8, this dsl device is a 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 is used to obtain local side DSL access and multiplexing device and 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 receive the first time of reception Ts1 of this very first time synchronizing signal and obtain this user side DSL modulator-demodulator and send second transmitting time Ts2 of 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;

This side-play amount computing unit 802 is used for the first transmitting time Tm1 that obtains 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 and calculates clock offset between this user side DSL modulator-demodulator and this local side DSL access and multiplexing device;

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

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

By the foregoing description as can be known, the default bit of uplink and downlink signals in transmission convergence sublayer reads local zone time by local side DSL access and multiplexing device and user side DSL modulator-demodulator, make user side DSL modulator-demodulator obtain the transmitting-receiving time of uplink and downlink signals in the digital line system, and according to the Time Calculation clock offset that obtains, thereby realized the time synchronization problem in the digital line system.

Embodiment 5

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

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

Wherein, this first receiving element 901 is used to receive the very first time synchronizing signal that local side DSL access and multiplexing device sends; 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 zone time Ts1 ', to obtain the first time of reception Ts1;

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

This second receiving element 905 is used to receive the 3rd time synchronizing signal that local side DSL access and multiplexing device sends; The 3rd acquiring unit 906 is used for obtaining the first transmitting time Tm1 from the 3rd time synchronizing signal that this second receiving element 905 receives; 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; Perhaps be 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 ' is proofreaied and correct the time that the back obtains;

The 3rd receiving element 907 is used to receive the 4th time synchronizing signal that local side DSL access and multiplexing device sends; The 4th acquiring unit 908 is used for obtaining the second time of reception Tm2 from the 4th time synchronizing signal that the 3rd receiving element 907 receives; 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 second time synchronizing signal reads in transmission convergence sublayer; Perhaps be local side DSL access and multiplexing device the 4th local zone time Tm2 ' that the second default bit of second time synchronizing signal reads in transmission convergence sublayer, and the 4th local zone time Tm2 ' is proofreaied and correct the time that the back obtains.

In the present embodiment, this first acquiring unit 902 also can be after reading the first local zone time Ts1 ', and Ts1 ' proofreaies and correct to this first local zone time, further improves the precision of time synchronized.Therefore,

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

Wherein, this first reading unit 1,001 first default bit of being used for the very first time synchronizing signal that receives at this first receiving element of transmission convergence sublayer 901 reads the first local zone time Ts1 ';

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

This first correcting unit 1003 be used to utilize this first determining unit 1002 determines first time of delay Δ T1 proofread and correct the first local zone time Ts1 ' that this first reading unit 1001 is read; First local zone time after the 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 Ts2 ' proofreaies and correct to this second local zone time, further improves the precision of time synchronized.Therefore,

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

Wherein, this second reading unit 1,101 second default bit of being used for second time synchronizing signal that sends at this first transmitting element of transmission convergence sublayer 903 reads the second local zone time Ts2 ';

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

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

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

Like this, when the position that this first reading unit 1001 reads first local zone time Ts1 ' correspondence be during i module: this first determining unit 1002 determine 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 zone time Ts1 ', comprising: the first local zone time Ts1 ' that will read deduct first time of delay Δ T1;

When the position that this second reading unit 1101 reads 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 a natural number, and i is 1 to n natural number.

Further, n the module that connects successively that comprise of user side DSL modulator-demodulator can be: the analog circuit of Lian Jieing, A/D converter, PMD module, PMS-TC module and TPS-TC module 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 counter in the user side DSL modulator-demodulator obtain 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 repeat no more as step 501 among the embodiment 3 as described in the step 504 herein.

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

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

By the foregoing description as can be known, 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 the digital line system, and, can realize the time synchronized in the digital line system according to the Time Calculation clock offset that obtains; Obtain time of delay by the mode that counter is set, can eliminate that up-downgoing difference time of delay further improves the precision of time synchronized to the influence of time synchronized in the digital subscriber line.

Embodiment 6

The embodiment of the 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: first processing unit 1201 and second processing unit 1202;

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

This second processing unit 1202 is used for user side DSL modulator-demodulator is sent to user side DSL modulator-demodulator to the second time of reception Tm2 of second time synchronizing signal of this local side DSL access and multiplexing device transmission, makes this user side DSL modulator-demodulator obtain the time of reception Tm2 of 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; Second of the second time synchronizing signal default bit reads local zone time and obtains the second time of reception Tm2 in transmission convergence sublayer.

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

Embodiment 7

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

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

Wherein, this second transmitting element 1301 is used for sending very first time synchronizing signal to user side DSL modulator-demodulator; The 5th acquiring unit 1302 is used for reading the 3rd local zone time Tm1 ' at the first default bit of the very first time synchronizing signal of 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 time synchronizing signal that the 3rd transmitting element 1303 is used for comprising this first transmitting time Tm1 is sent to user side DSL modulator-demodulator.

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

The 3rd determining unit 1402 be used for determining 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 be used to utilize 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 the 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 4th receiving element 1501 is used to receive second time synchronizing signal that user side DSL modulator-demodulator sends to local side DSL access and multiplexing device; The 6th acquiring unit 1502 is used for reading the 4th local zone time Tm2 ' at the second default bit of second time synchronizing signal of transmission convergence sublayer the 4th receiving element 1501 receptions, to obtain the second time of reception Tm2 of second time synchronizing signal; The 4th time synchronizing signal that the 4th transmitting element 1503 is used for comprising the second time of reception Tm2 is sent to user side DSL modulator-demodulator.

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 1,601 second default bit that is used for second time synchronizing signal that receives at transmission convergence sublayer the 4th receiving element 1501 reads the 4th local zone time Tm2 ';

The 4th determining unit 1602 be used for determining 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 be used to utilize 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 the correction is the second time of reception Tm2.

In the present embodiment, this local side DSL access and multiplexing device comprises n the module that connects 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 ' that reads, 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 ' that reads, comprising: the 4th local zone time Tm2 ' that will read deduct the 4th time of delay Δ T4;

Wherein, n is a natural number, and i is 1 to n natural number.

In the present embodiment, n the module that connects successively that comprise of local side DSL access and multiplexing device can be: the TPS-TC module of Lian Jieing, PMS-TC module, PMD module, A/D converter and analog circuit 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 counter in the local side DSL access and multiplexing device obtain 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 repeat no more as step 501 among the embodiment 3 as described in the step 504 herein.

Embodiment 8

The embodiment of the 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 the 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.

By the foregoing description as can be known, 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 the digital line system, and, can realize the time synchronized in the digital line system according to the Time Calculation clock offset that obtains.

The professional can also further recognize, the 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, the composition and the step of each example described prevailingly according to function in the above description.These functions still are that software mode is carried out with hardware actually, depend on the application-specific and the design constraint of technical scheme.The professional and technical personnel can use distinct methods to realize described function to each specific should being used for, but this realization should not thought and exceeds scope of the present invention.

The method of describing in conjunction with embodiment disclosed herein or the step of algorithm can use the software module of hardware, processor execution, and perhaps the combination of the two is implemented.Software module can place 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 the technical field.

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

Claims

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

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

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

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

2. method for synchronizing time according to claim 1 is characterized in that, described first equipment is local side DSL access and multiplexing device; Described second equipment is the user side dsl device.

3. method for synchronizing time according to claim 2, it is characterized in that, described second equipment obtains first equipment and sends first transmitting time Tm1 of very first time synchronizing signal and the first time of reception Ts1 that described second equipment receives described very first time synchronizing signal and second equipment that obtains to second equipment and send second transmitting time Ts2 of second time synchronizing signal and the second time of reception Tm2 that described first equipment receives described second time synchronizing signal to first equipment, comprising:

Second equipment receives the very first time synchronizing signal that first equipment sends, and presets bit in first of the synchronizing signal of the very first time described in the transmission convergence sublayer and reads the first local zone time Ts1 ', to obtain the described first time of reception Ts1;

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

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

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

4. method for synchronizing time according to claim 3, it is characterized in that, described second equipment receives the very first time synchronizing signal that first equipment sends, the first default bit in the synchronizing signal of the very first time described in the transmission convergence sublayer reads the first local zone time Ts1 ', to obtain the described first time of reception Ts1, comprising:

Described second equipment receives the very first time synchronizing signal that first equipment sends, and presets bit in first of the synchronizing signal of the very first time described in the transmission convergence sublayer and reads the first local zone time Ts1 ';

Determine described very first time synchronizing signal in described 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 zone time Ts1 ';

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

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

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

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

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

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

Time acquisition unit is used to obtain local side DSL access and multiplexing device and sends 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 second transmitting time Ts2 of second time synchronizing signal and the second time of reception Tm2 that described local side DSL access and multiplexing device receives described second time synchronizing signal to described local side DSL access and multiplexing device;

7. user side dsl device according to claim 6 is characterized in that, described time acquisition unit comprises:

First receiving element is used to receive the very first time synchronizing signal that described local side DSL access and multiplexing device sends;

First acquiring unit, first of the very first time synchronizing signal default bit reads the first local zone time Ts1 ' described in the transmission convergence sublayer that is used for receiving at described first receiving element, to obtain the described first time of reception Ts1;

First transmitting element is used for sending second time synchronizing signal to described local side DSL access and multiplexing device;

Second acquisition unit, second of the second time synchronizing signal default bit reads the second local zone time Ts2 ' described in the transmission convergence sublayer that is used for sending at described first transmitting element, to obtain the described second transmitting time Ts2;

Second receiving element is used to receive the 3rd time synchronizing signal that described local side DSL access and multiplexing device sends;

The 3rd acquiring unit is used for obtaining the described first transmitting time Tm1 from described the 3rd time synchronizing signal that described second receiving element receives; The described first transmitting time Tm1 is that described local side DSL access and multiplexing device is preset the 3rd local zone time Tm1 ' that bit reads in described first of the synchronizing signal of the very first time described in the transmission convergence sublayer; Perhaps preset the 3rd local zone time Tm1 ' that bit reads in described first of the synchronizing signal of the very first time described in the transmission convergence sublayer, and described the 3rd local zone time Tm1 ' is proofreaied and correct the time that the back obtains for described local side DSL access and multiplexing device;

The 3rd receiving element is used to receive the 4th time synchronizing signal that local side DSL access and multiplexing device sends;

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

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

9. local side DSL access and multiplexing device according to claim 8 is characterized in that, described first processing unit comprises:

Second transmitting element is used for sending very first time synchronizing signal to described user side dsl device;

The 5th acquiring unit, the first default bit that is used for the very first time synchronizing signal that sends at second transmitting element described in the transmission convergence sublayer reads the 3rd local zone time Tm1 ', to obtain the first transmitting time Tm1 of described very first time synchronizing signal; Perhaps, the first default bit that is used for the described very first time synchronizing signal that sends at second transmitting element described in the transmission convergence sublayer reads the 3rd local zone time Tm1 '; 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 the correction is the described first transmitting time Tm1;

The 3rd transmitting element, the 3rd time synchronizing signal that is used for comprising the described first transmitting time Tm1 is sent to described user side dsl device.

10. local side DSL access and multiplexing device according to claim 8 is characterized in that, described second processing unit comprises:

The 4th receiving element is used to receive second time synchronizing signal that described user side dsl device sends to described local side DSL access and multiplexing device;

The 6th acquiring unit, the second default bit that is used for described second time synchronizing signal that receives at the 4th receiving element described in the transmission convergence sublayer reads the 4th local zone time Tm2 ', to obtain the second time of reception Tm2 of described second time synchronizing signal; Perhaps, the second default bit that is used for described second time synchronizing signal that receives at the 4th receiving element described in the transmission convergence sublayer reads the 4th local zone time Tm2 '; Determine described 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 the correction is the described second time of reception Tm2;

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

11. 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 the user side dsl device; It is characterized in that,

Described user side dsl device comprises claim 6 or 7 described dsl devices; Described local side DSL access and multiplexing device comprises the described local side DSL of each claim access and multiplexing device of claim 8 to 10.