CN101651535B - Method and system for recovering self-adapted service clock based on PTN - Google Patents
Method and system for recovering self-adapted service clock based on PTN Download PDFInfo
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- CN101651535B CN101651535B CN2009101900001A CN200910190000A CN101651535B CN 101651535 B CN101651535 B CN 101651535B CN 2009101900001 A CN2009101900001 A CN 2009101900001A CN 200910190000 A CN200910190000 A CN 200910190000A CN 101651535 B CN101651535 B CN 101651535B
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Abstract
The invention discloses a method and a system for recovering a self-adapted service clock based on PTN. The method comprises the following steps: a PTN service inlet sends a service data packet by using a source clock so that the service data packet is transmitted to a PTN service outlet through a packet transport network; the PTN service outlet receives the service data packet; the PTN service outlet recovers the service clock from the service data packet by using a reference clock as a working clock; and the PTN service outlet analyzes the service data packet into corresponding service and transmits the corresponding service by using the service clock. The method and the system for recovering the self-adapted service clock based on the PTN effectively reduce the shake of the service clock and obviously enhance the network property of the PTN network.
Description
Technical field
The present invention relates to field of mobile communication, relate in particular to a kind of based on PTN (PackageTransport Network: Packet Transport Network) recovering self-adapted service clock method and system thereof.
Background technology
PTN supports multiple two-way point-to-point interface channel based on packet switching service, has the various thickness particle business of being fit to networking capability end to end, be a kind ofly can provide the carrier class Ethernet service, time division multiplexing), ATM (Asynchronous Transfer Mode: asynchronous transfer mode), ML-PPP (Multi Link Pointto Point Protocol: the MultiLink PPP agreement) wait the comprehensive transmission network technology of business compatible traditional simultaneously TDM (Time Division Multiplexing:.PTN equipment is meant the optical transmission equipment of new generation that transmits towards grouping, and PTN equipment can provide efficiently Packet Service and transmit.
When the business datum of PTN equipment carrying TDM business wraps in when transmitting in the Packet Transport Network, usually need to guarantee the synchronous transmission function of PTN ingress for service and the professional outlet of PTN, therefore, the professional outlet of clockwise PTN sent after the business data packet when PTN ingress for service adopted the source, the professional outlet of PTN need obtain the business clock synchronous as far as possible with the source clock by the clock recovery technology usually, and transmits corresponding business by this business clock.At present, clock recovery technology commonly used mainly comprises two kinds in the PTN data transmission procedure: adaptive clock recovery technology and differential clocks recovery technology.
Wherein, the adaptive clock recovery technology is meant that the professional outlet of PTN recovers the technology of business clock according to the receive frequency of business data packet, as shown in Figure 1, its operation principle is: PTN ingress for service 10 adopts the source clock that business data packet is sent to the professional outlet of PTN by PTN, after receiving business data packet, the adaptive clock recovery module 20 of the professional outlet of PTN recovers business clock, after professional receiver module 30 receives business data packet it is resolved, and adopt the business after the business clock that recovers will be resolved to send.It is a process at the uniform velocity to the PTN network that PTN ingress for service 10 adopts the up package of source clock, and downstream packets is subjected to factor affecting such as network jitter and drift when arriving at the professional outlet of PTN, it is the time interval and incomplete the equating between each business data packet, the source clock information that has reflected PTN ingress for service 10 its blanking time indirectly, the professional outlet of PTN can recover business clock according to the speed that arrives at of business data packet.Yet, because business datum wraps in the signal that can be subjected to unavoidably to a certain degree in the grouping transport process and disturbs, the professional outlet of PTN directly recovers shake and the drift that business clock obviously can cause clock frequency, therefore need take the measure of trembling to make business clock reach the certain precision index, obtain as far as possible and the complete synchronous business clock of source clock, to guarantee the transmittability of network.
In the existing P TN data transmission technology, usually adopt some algorithms to realize the adaptive clock recovery technology, promptly dispose software with clock jitter removing function in adaptive clock recovery module 20, yet, existing various algorithm is relatively poor for the filtration result of clock jitter, treated business clock still is difficult to satisfy the clock index of regulation, thereby has caused the decline of network performance.
Summary of the invention
Technical problem to be solved by this invention is that a kind of recovering self-adapted service clock method and system thereof based on PTN that effectively reduces clock jitter, improves network performance is provided.
The technical solution adopted for the present invention to solve the technical problems is: a kind of recovering self-adapted service clock method based on PTN is provided, may further comprise the steps: the PTN ingress for service adopts the source clock to send business data packet, makes described business data packet be sent to the professional outlet of PTN by Packet Transport Network; The professional outlet of PTN receives described business data packet; The professional outlet of PTN recovers business clock as work clock with reference clock from described business data packet; The professional outlet of PTN resolves to corresponding service with described business data packet, and adopts described business clock to transmit described corresponding service.
The production method of described reference clock is: the professional outlet of PTN is imported outside de-twitter circuit with local clock, makes its output reference clock.
Perhaps, the production method of described reference clock is: the professional outlet of PTN will be imported outside de-twitter circuit from the system clock of PTN equipment, make its output reference clock.
Described business is the TDM business.
A kind of recovering self-adapted service clock system based on PTN comprises the professional outlet of PTN ingress for service, Packet Transport Network and PTN, and the professional outlet of PTN comprises professional receiver module, adaptive clock recovery module and outside de-twitter circuit; The PTN ingress for service is used to adopt the source clock to send business data packet, makes described business data packet be sent to the professional outlet of PTN by Packet Transport Network; Outside de-twitter circuit is used to produce reference clock, and exports described reference clock to the adaptive clock recovery module; The adaptive clock recovery module is used to receive described business data packet, and reference clock is recovered business clock as work clock from described business data packet; After professional receiver module is used to receive described business data packet it is resolved to corresponding service, also be used for sending described corresponding service according to the business clock of described adaptive clock recovery module output.
The professional outlet of described PTN comprises also that logic configuration module, described outside de-twitter circuit also comprise and trembles process chip and loop filtering circuit; The logic configuration module is used for going to tremble process chip and carrying out initial configuration and parameter configuration described; Go to tremble process chip and be used for producing reference clock by system clock or local clock from PTN equipment, and with described reference clock input adaptive clock recovery module; The loop filtering circuit is used to and describedly goes to tremble process chip peripheral filter circuit is provided.
The filtering capacitance-resistance parameter of described loop filtering circuit is provided with according to the described simulation result that goes to tremble the process chip configuration parameter.
A kind of preferred embodiment in, it is described that to go to tremble process chip be AD9516.
The invention has the beneficial effects as follows, the present invention is based in the recovering self-adapted service clock method and system thereof of PTN, the professional outlet of PTN is when carrying out clock recovery, employing from the reference clock of outside de-twitter circuit as reliable and stable reference clock source, effectively reduced the shake of business clock, make the business clock that obtains and the source clock of PTN ingress for service be tending towards having significantly improved the network performance of clock accuracy and PTN synchronously.
Further, the recovering self-adapted service clock system that the present invention is based on PTN comprises that also can tremble process chip to going in the outside de-twitter circuit is configured, and makes it strengthen the flexibility of its use.
Description of drawings
Fig. 1 is existing business clock processing scheme schematic diagram based on PTN;
Fig. 2 is a kind of embodiment flow chart of the recovering self-adapted service clock method based on PTN of the present invention;
Fig. 3 is first kind of embodiment schematic diagram of recovering self-adapted service clock system based on PTN of the present invention;
Fig. 4 is first kind of embodiment schematic diagram of recovering self-adapted service clock system based on PTN of the present invention.
Embodiment
The invention provides a kind of technical scheme that improves the clock accuracy index of the professional outlet of PTN by outside de-twitter circuit, make the professional source clock that recovers with the PTN ingress for service that exports of PTN be tending towards synchronous business clock, and adopt this business clock that business is transmitted.Below in conjunction with accompanying drawing the specific embodiment of the present invention is elaborated.
As Fig. 1 is a kind of embodiment flow chart of the recovering self-adapted service clock method based on PTN of the present invention, may further comprise the steps:
Step S100: system's preparation that powers on, comprise that the outside de-twitter circuit to the professional outlet of PTN loads configuration, make its operate as normal.
The business that step S101:PTN ingress for service will need to transmit is packaged into business data packet, prepares to transmit by Packet Transport Network, and business comprises that ATM is professional or other are professional.
Step S102:PTN ingress for service adopts the source clock to send business data packet, makes business data packet arrive the professional outlet of PTN by Packet Transport Network.
The professional outlet of step S103:PTN receives business data packet, and is used for the professional business clock that transmits by the reference clock generation, promptly recovers with the source clock to be tending towards synchronous business clock from business data packet.
This reference clock derives from outside de-twitter circuit, can produce in several ways: for example can be and tremble the local clock of processing or the system clock of PTN equipment through in the past, for example the professional outlet of PTN can be imported local clock outside de-twitter circuit, makes its output reference clock.A kind of preferred embodiment in, the professional outlet of PTN can make it produce reference clock with import outside de-twitter circuit from the system clock of PTN equipment.The professional outlet of PTN can recover business clock as work clock according to the receive frequency of business data packet with reference clock.Because the professional outlet of PTN is when carrying out clock recovery, employing from the reference clock of outside de-twitter circuit as reliable and stable reference clock source, therefore effectively reduced the shake of business clock, make the business clock that obtains and the source clock of PTN ingress for service be tending towards having significantly improved the network performance of clock accuracy and PTN synchronously.
The professional outlet of step S104:PTN resolves to corresponding service with business data packet, and adopts the business clock that recovers to transmit corresponding service.
As Fig. 3 is first kind of embodiment schematic diagram of recovering self-adapted service clock system based on PTN of the present invention.Comprise the professional outlet of PTN ingress for service 10, Packet Transport Network and PTN, the professional outlet of PTN is provided with professional receiver module 30, adaptive clock recovery module 20 and outside de-twitter circuit 40.
PTN ingress for service 10 is used for the business that needs transmit is packaged into business data packet, and adopts the source clock to send this business data packet, makes it arrive the professional outlet of PTN by Packet Transport Network.
Outside de-twitter circuit 40 is used to produce reference clock, and exports it to adaptive clock recovery module 20.
Adaptive clock recovery module 20 is used to receive business data packet, and recovers from business data packet with the source clock according to the receive frequency of business data packet by reference clock and to be tending towards synchronous business clock.
After professional receiver module 30 is used to receive business data packet, it is resolved to corresponding service, the business clock that also is used for recovering according to adaptive clock recovery module 20 transmits corresponding service.
In second kind of embodiment as shown in Figure 4, the professional outlet of PTN comprises also that logic configuration module 50, outside de-twitter circuit 40 also comprise and trembles process chip and loop filtering circuit 41, for example goes to tremble process chip and can be AD9516.
Wherein, logic configuration module 50 is used for carrying out initial configuration and parameter configuration to going to tremble process chip, go to tremble process chip (AD9516) and produce reference clock by system clock from PTN equipment 60, and with described reference clock input adaptive clock recovery module 20, loop filtering circuit 41 is used to be trembled process chip peripheral filter circuit is provided, and goes to tremble process chip and also can produce reference clock by local clock.
AD9516 is applicable to the applied environment that requires low phase noise and low jitter in the clock path, in the present embodiment, logic configuration module 50 need be carried out parameter configuration to AD9516, thereby strengthens the flexibility that outside de-twitter circuit uses, and its layoutprocedure may further comprise the steps:
(1) calculation of parameter, i.e. the frequency computation part VCO operating frequency of exporting as required.Need respectively to suppose f
1And f
2Two kinds of different output frequencies, VCO operating frequency must be frequency f
1And f
2Least common multiple.Note this least common multiple minimum be 2 frequencys multiplication, and must drop on after the frequency multiplication within the scope of built-in VCO operating frequency.
(2) according to input reference frequency f
REFWith VCO operating frequency f
VCOCalculate phase demodulation frequency, phase demodulation frequency is a frequency f
REFAnd f
VCOGreatest common divisor.In order to obtain better clock performance and precision of phase discrimination, phase demodulation frequency is high more good more, influences output performance but should not surpass 500MHz to avoid phase demodulation frequency to reveal.
(3) above calculating in VCO operating frequency and the phase demodulation frequency process, common multiple or pact are handled and are obtained divider ratios such as each passage frequency division, R frequency division and Fractional-N frequency.
(4) the read-write operation interface of configuration AD9516 makes CPU carry out read-write operation to AD9516.
(5) initialization AD9516 is according to the R frequency division that calculates, Fractional-N frequency and each the passage frequency division register by logic configuration block configuration AD9516.
(6) logic configuration success, the AD9516 operate as normal makes it finish the input and output of clock according to logic configuration, reference clock is provided for adaptive clock recovery module 20.
Because AD9516 belongs to the APLL analog phase-locked look, the design of loop bandwidth can not be too narrow, otherwise can influence loop stability and locking time, and loop bandwidth is typically chosen in the reference signal noise and is the best with the VCO noise place of equating.The filtering capacitance-resistance parameter of loop filtering circuit 41 is provided with according to the described simulation result that removes to tremble the configuration parameter of process chip, be loop bandwidth and the internal register configuration parameter of loop filtering circuit 41 according to AD9516, use the software emulation that ADI provides and the loop filtering capacitance-resistance parameter that obtains, can further guarantee filtering and the clock jitter removing effect of AD9516.
Above content be in conjunction with concrete preferred implementation to further describing that the present invention did, can not assert that concrete enforcement of the present invention is confined to these explanations.For the general technical staff of the technical field of the invention, without departing from the inventive concept of the premise, can also make some simple deduction or replace, all should be considered as belonging to protection scope of the present invention.
Claims (7)
1. the recovering self-adapted service clock method based on Packet Transport Network PTN is characterized in that, may further comprise the steps:
The PTN ingress for service adopts the source clock to send business data packet, makes described business data packet be sent to the professional outlet of PTN by Packet Transport Network;
The professional outlet of PTN receives described business data packet;
The professional outlet of PTN will recover business clock as work clock from the reference clock of outside de-twitter circuit from described business data packet;
The professional outlet of PTN resolves to corresponding service with described business data packet, and adopts described business clock to transmit described corresponding service.
2. method according to claim 1 is characterized in that: the production method of described reference clock is: the professional outlet of PTN is imported outside de-twitter circuit with local clock, makes its output reference clock.
3. method according to claim 1 is characterized in that: the production method of described reference clock is: the professional outlet of PTN will be imported outside de-twitter circuit from the system clock of PTN equipment, make its output reference clock.
4. according to each described method in the claim 1 to 3, it is characterized in that: described business is the time division multiplexing tdm business.
5. recovering self-adapted service clock system based on Packet Transport Network PTN, comprise the professional outlet of PTN ingress for service, Packet Transport Network and PTN, it is characterized in that: the professional outlet of PTN comprises professional receiver module, adaptive clock recovery module and outside de-twitter circuit;
The PTN ingress for service is used to adopt the source clock to send business data packet, makes described business data packet be sent to the professional outlet of PTN by Packet Transport Network;
Outside de-twitter circuit is used to produce reference clock, and exports described reference clock to the adaptive clock recovery module;
The adaptive clock recovery module is used to receive described business data packet, and reference clock is recovered business clock as work clock from described business data packet;
After professional receiver module is used to receive described business data packet it is resolved to corresponding service, also be used for sending described corresponding service according to the business clock of described adaptive clock recovery module output.
6. system according to claim 5 is characterized in that: the professional outlet of described PTN comprises also that logic configuration module, described outside de-twitter circuit also comprise and trembles process chip and loop filtering circuit;
The logic configuration module is used for going to tremble process chip and carrying out initial configuration and parameter configuration described;
Go to tremble process chip and be used for producing reference clock by system clock or local clock from PTN equipment, and with described reference clock input adaptive clock recovery module;
The loop filtering circuit is used to and describedly goes to tremble process chip peripheral filter circuit is provided.
7. system according to claim 6 is characterized in that: the filtering capacitance-resistance parameter of described loop filtering circuit is provided with according to the described simulation result that goes to tremble the process chip configuration parameter.
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| Application Number | Priority Date | Filing Date | Title |
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| CN2009101900001A CN101651535B (en) | 2009-09-01 | 2009-09-01 | Method and system for recovering self-adapted service clock based on PTN |
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|---|---|---|---|
| CN2009101900001A CN101651535B (en) | 2009-09-01 | 2009-09-01 | Method and system for recovering self-adapted service clock based on PTN |
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| CN101651535A CN101651535A (en) | 2010-02-17 |
| CN101651535B true CN101651535B (en) | 2011-12-28 |
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| CN101984564A (en) * | 2010-11-23 | 2011-03-09 | 中兴通讯股份有限公司 | Implementation method of adaptive clock holdover mode and device thereof |
| CN102487301A (en) * | 2010-12-01 | 2012-06-06 | 中兴通讯股份有限公司 | Method and device for recovering multilink clock |
| CN102957488B (en) * | 2011-08-18 | 2016-09-28 | 中兴通讯股份有限公司 | A kind of time synchronized selects source method and device |
| CN113406993A (en) * | 2021-07-16 | 2021-09-17 | 盛立安元科技(杭州)股份有限公司 | FPGA chip clock domain synchronization method based on recovered clock and related equipment |
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