CN1992572B - Method and apparatus for multiplexing from low-speed light port to 2M transmission line and protection switching - Google Patents
Method and apparatus for multiplexing from low-speed light port to 2M transmission line and protection switching Download PDFInfo
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Abstract
This invention discloses a method and device that directly multiplexing connects multiple low-speed rate optical interfaces to 2M standard transmission line, and automatic protection switching. The method as following: receiving the low-speed optical signal of the low-speed optical interfaces, processing photoelectric conversion and clock extraction, decoding and buffering; using 2M clock to generate 2M data accordant to ITU-T G.704 proposal, and under the control of the 2M clock, inserting the decoded low-speed data into 2M data flow, to complete the multiplexing of the low-speed data; checking the 2M data flow by Cyclic Redundancy Check rules, and generating the correcting code word, and inserting the code word into the CRC bit of the 2M data flow, through at least two transmission lines to send the data. The receiver of the other end device does transmission quality analysis to the received two-way data, and selects the best quality to de-multiplex to low-speed data, and through line coding and electro-optical, converts to the optical signal to output. The invention also discloses the device based on the above method. This invention guarantees and improves the data communication quality, with low maintenance costs.
Description
Technical field
The present invention relates to a kind of communication means and device, relate in particular to the method and apparatus of the data communication that a kind of low speed optical interface that is applied in the relay protection device switches to 2M bandwidth reuse and protection based on PCM multiple connection 2M data.
Background technology
Relay protection device be electric power system be used for monitoring the ruuning situation of power network in real time and in the power plant, the equipment that the control electric brake is switched when unusual appears in the high-tension line of power distribution station.This equipment all is paired use, and whether terminal device controls electric brake through the decisions such as voltage and current parameter on the common calculating high-voltage line is switched.Mostly the communication interface of equipment is the low speed optical fiber interface; This is because relay protection device is installed in the forceful electric power magnetic environment; Optical fiber interface has good antijamming capability; And only need just can satisfy its performance requirement between a pair of equipment less than the bandwidth of 2M, and therefore most of producers are defined as 64Kb/s between the 4M with this optical fiber interface line speed, and payload is less than the low speed optical fiber interface of 2M.Relay protection device is the power equipment that belongs to important in electric power system; Its communications circuit will be guaranteed reliably, just can make its operate as normal, in case telecommunication transmission system breaks down; Electric power safety can be had a strong impact on, also great electric power accident maybe be caused when serious.The develop rapidly of electric power system constantly proposes new requirement to relaying protection, and the develop rapidly of electronic technology, computer technology and the communication technology has constantly been injected new vitality for the development of Protection Technology again.At present, for the data reliability that guarantees relay protection device is transmitted several kinds of solutions that propose, but certain shortcoming and limitation are arranged all.The miscellaneous equipment of electric power system also has identical problem with the data reliability transmission that some of telecom operators has the data terminal equipment of low speed optical fiber interface and data particular importance, therefore also needs reliable solution to solve the transmission reliability of these equipment.
Because the domestic not low speed optical fiber interface of standard definition relay protection device causes the optical fiber interface of the relay protection device of each producer on the present domestic market to have nothing in common with each other.Each producer's equipment in use, its communications mode has following several kinds.
A kind of mode is to use the fiber direct connection mode; The low speed optical fiber interface of two equipment of being about to directly links to each other with a pair of optical fiber, and in system of relay protection, this mode is usually used between the small-sized transformer station; Have only a pair of relay protection device to interconnect between two stations, and distance have only several kilometers.Far away for transmission range, the more situation of equipment just has been not suitable for.Shortcoming is: need be the special laying optical cable of this low speed data, cost is high, can't make full use of and use already used common transmission system such as SDH etc.And can't use the 1+1 backup of optical fiber, its reliability can not get ensureing.The second way is the mode of light/electricity conversion+PCM (branch multiple connection) equipment of split.This is the mode that present most of electric power operator takes.At communications equipment room away from the electric power machine room, light/electric conversion equipment is installed, convert the low speed optical fiber interface into the low speed data interface, like 64Kb/s interface in the same way, V35 interface, RS485 interface etc., the maximum of usefulness are same directional 64K b/S interfaces at present.This low speed data interface is multiplexed in the E1 interface through PCM equipment again, transmits through PDH, SDH optical transceiver or microwave system then.With regard to present present situation, light/electric conversion equipment safeguards that by relaying protection department PCM equipment is safeguarded by power communication department, usually owing to the back that has an accident is difficult to find the fault point dispute takes place between the two.Because the terminal equipment of low speed optical interface does not in the market have unified standard, the light of each coordinative composition of equipments/electric conversion equipment is also multifarious, can't be compatible between each equipment, and this brings huge maintenance cost for plant maintenance department.What PCM equipment then used all is general PCM equipment, its interface comprise RS232, RS422, RS485, V.11, numerous interfaces such as V35, same directional 64K b/s, IP, plain old telephone, EM4/EM2, so institute's loaded service kind is many.In order to ensure that miscellaneous service normally uses, just can't ensure the line quality of a certain particular service of having relatively high expectations such as relaying protection, and the asynchronous problem of being brought by multi-service of clock is also very outstanding.And if only carry this particular service, numerous interfaces of then whole PCM equipment just can't use, and cause the significant wastage of resource.Also increased simultaneously the complexity of safeguarding.
But the transfer of data of relay protection device should reliably be guaranteed; The 1+1 backup mode of communications circuit is that electric power operator is for solving the effective means that transmission reliability is taked; And there is redundant transmission line electric power operation commercial city, material base is provided for the 1+1 backup mode.Based on the 1+1 backup mode, following several kinds of solutions are arranged at present.
First kind of mode is two fiber direct connection modes, and this mode is because cost is high, and poor reliability is only used between small-sized transformer station.
The second way is the light/electricity conversion+PCM multiplex equipment+SDH Self-healing Rings mode of split.In relaying protection system; The maximum weakness of SDH Self-healing Rings is to ensure that bi-directional data can be through identical route; Thereby can not ensure two-wayly have identical time-delay, but two-wayly have the basic demand that identical time-delay is a relay protection device, otherwise relay protection device cisco unity malfunction.The third mode is the manual switching mode of the light/electricity conversion+PCM equipment+2M of split.The prerequisite here is to have two transmission routes, provides 2 2M transmission channels to use to a pair of relay protection device respectively.Electric power provides two kinds of transmission routes, and some places are the mode of two-way optical fiber, and some places are the mode of one road optical fiber, one road microwave.The shortcoming of this mode is except the shortcoming of the light/electricity conversion ten PCM DeviceModes of above-mentioned split; The manual switching of 2M safeguarded inconvenience, gives birth to fault in case riches all the way, needs manual another road that switches to; Communicate by letter and will interrupt fully during the manual line falling cable, the equipment safety in utilization will be greatly affected.
Summary of the invention
To existing problem and shortage in above-mentioned existing low speed optical interface data multiplexing and protection changing method and the device, the purpose of this invention is to provide and a kind ofly can guarantee and improve data communication quality, maintenances is simple, easy to operate, cost is low, simple and easy to do low speed optical interface to the multiplexing of 2M transmission line with protect changing method and device.
The present invention is achieved in that the method that the low speed optical interface switches to the multiplexing of 2M transmission line and protection, may further comprise the steps:
A, forwarding step:
(1) receives the low speed light signal of low speed optical interface input, this low speed light signal is carried out opto-electronic conversion and Clock Extraction, utilize the clock that extracts the data row cache of going forward side by side of decoding;
(2) utilize the 2M clock to generate the 2M data flow of ITU-TG.704 regulation: under the control of 2M clock; According to the speed of low speed data will decode and buffer memory after low speed data be inserted into the ITU-TG.7042M data format that forms standard in the 2M data flow of said ITU-TG.704 regulation, thereby completion multiplexing to low speed data;
(3) said 2M data flow is carried out verification by corresponding CRC rule, and produce check results, this check results is inserted into the CRC position of said 2M data flow, and send these data simultaneously through two-way transmission line at least;
B, receiving step:
(1) the said 2M of two-way at least data flow is carried out Clock Extraction after receiving the 2M of the two-way at least data flow of 2M interface input; Utilize the 2M data in this said 2M of two-way at least data flow of 2M Clock Extraction of extracting; And carry out frame synchronization and CRC; Carry out the transmission quality analysis then, select a road best 2M data flow, from this road best 2M data flow, extract low speed data and promptly demultiplex into low speed data according to the quality analysis result;
(2) under the control of low-speed clock, the low speed data behind the demultiplexing is carried out respective coding;
(3) low speed data behind the coding is carried out electricity/light conversion, at the light signal that passes through under the control of low-speed clock after the low speed optical interface sends this conversion;
This method also comprises step: when after multiplexing to low speed data, proceeding to the transmission of few two-way; Data-signal with this after multiplexing carries out piecemeal; Add the different time label for each data block, with identical data in the order of nominal data piece and the different transmission line; When receiving terminal is handled these different track datas that receive; Can think that the data block with identical time tag is exactly same blocks of data; Promptly only can confirm with the label of comparison two paths of signals whether the data block of two-way is identical data block; So that two paths of signals aligns, be beneficial to circuit and carry out undamaged switching.
The low speed optical interface is to the multiplexing of 2M transmission line and protection device for switching; Include the photoelectricity/electrooptic conversion module based on low-speed interface, the PCM that are electrically connected successively and divide multiple connection module, circuit automatic switchover module; Said photoelectricity/electrooptic conversion module divides the multiple connection module to be connected with PCM, and said PCM divides the multiple connection module to be connected with said circuit automatic switchover module; Said photoelectricity/electrooptic conversion module includes the light signal input/output module that is used for light signal input and output, opto-electronic conversion and inverse conversion; Utilize corresponding clock to carry out the coding/decoding module of light signal encoding and decoding; The clock of more than one frequency pulses can be provided; The loopback control module that is used for the signal loopback test is used for the buffer of metadata cache; Said PCM divides the multiple connection module to include to be used for low speed data is multiplexed into the 2M data flow and the 2M data flow is demultiplexed into the multiplexing and demultiplexing module of low speed data; Be used for markers is inserted into the markers insert module of the 2M data flow after multiplexing, be used for CRC is inserted into the CRC insert module of the 2M data flow after multiplexing; Said circuit automatic switchover module includes the alignment of data module that is used for the 2M of the two-way at least multiplexed data flow that receives is carried out markers extraction and alignment of data; Be used for the 2M data flow is carried out the chock smotthing module of chock smotthing; Be used for the said 2M of two-way at least multiplexed data flow is carried out the transmission quality analysis module that transmission quality is analyzed, be used to carry out the circuit handover module that switches between the said 2M of the two-way at least multiplexed data flow transmission line; Said photoelectricity/electrooptic conversion module, PCM divide multiple connection module and circuit automatic switchover module clock synchronization, and said photoelectricity/electrooptic conversion module and PCM divide the multiple connection module shared same loopback control module;
Said photoelectricity/electrooptic conversion module receives the low speed light signal of low speed optical interface input, and this low speed light signal is carried out opto-electronic conversion and Clock Extraction, utilizes the clock that extracts to the data row cache of going forward side by side of decoding;
Said PCM divides the multiple connection module to utilize the 2M clock to generate the 2M data flow of ITU-TG.704 regulation: under the control of 2M clock; According to the speed of low speed data will decode and buffer memory after low speed data be inserted into the ITU-TG.7042M data format that forms standard in the 2M data flow of said ITU-TG.704 regulation, thereby completion multiplexing to low speed data; Said 2M data flow is carried out verification by corresponding CRC rule, and produce check results, this check results is inserted into the CRC position of said 2M data flow, and send these data simultaneously through two-way transmission line at least;
Said circuit automatic switchover module is carried out Clock Extraction to the said 2M of two-way at least data flow after receiving the 2M of the two-way at least data flow of 2M interface input; Utilize the 2M data in this said 2M of two-way at least data flow of 2M Clock Extraction of extracting; And carry out frame synchronization and CRC; Carry out the transmission quality analysis then; Select a road best 2M data flow according to the quality analysis result, said PCM divides the multiple connection module from this road best 2M data flow, to extract low speed data promptly to demultiplex into low speed data; Said photoelectricity/electrooptic conversion module is under the control of low-speed clock; Low speed data behind the demultiplexing is carried out respective coding; Low speed data behind the coding is carried out electricity/light conversion, at the light signal that passes through under the control of low-speed clock after the low speed optical interface sends this conversion;
When said markers insert module proceeded to the transmission of few two-way after multiplexing to low speed data, the data-signal with this after multiplexing carried out piecemeal, adds the different time label for each data block, with identical data in the order of nominal data piece and the different transmission line; When receiving terminal is handled these different track datas that receive; Can think that the data block with identical time tag is exactly same blocks of data; Promptly only can confirm with the label of comparison two paths of signals whether the data block of two-way is identical data block; So that two paths of signals aligns, be beneficial to circuit and carry out undamaged switching.
It is the structure of one that the present invention adopts photoelectricity/electrooptic conversion module, PCM to divide multiple connection module and circuit automatic switchover module, has reduced the quantity of intermediate equipment, has reduced the fault point; Electrical interface is that standard becomes frame interface, and the convenient maintenance department that communicates by letter tests and safeguards; The present invention adopts the not damaged switching mode to improve transmission quality simultaneously, guarantees that transmission line is reliable and stable; Need not manual intervention, can carry out route protection automatically and switch; The present invention can adapt to the low speed optical interface of plurality of devices, thereby adapts to the conversion of the 2M data that G.704 multiple low speed data advise to ITU-T.The present invention can guarantee the operate as normal of relay protection device to the full extent, thereby guarantees the safe and reliable of power network.
Description of drawings
Fig. 1 is an application structure sketch map of the present invention:
Fig. 2 is the structural representation that opto-electronic conversion of the present invention, PCM divide multiple connection to realize;
Fig. 3 is the data transmission blocks structural representation of PCM of the present invention after multiplexing;
Fig. 4 is the harmless circuit-switched data reception module structural representation of the present invention;
Fig. 5 is a buffer read-write sketch map of the present invention;
Fig. 6 is a phase-locked loop structures sketch map of the present invention.
Embodiment
Below in conjunction with accompanying drawing the present invention is made further detailed description.
As shown in Figure 1; During use; Directly communicator of the present invention is connected between two relay protection devices, again through two-way (the present invention has specifically used two-way, is " 1+1 " form) transmission line connection at least; Communicator of the present invention includes the photoelectricity/electrooptic conversion module (O/E based on low-speed interface that is electrically connected successively; Optical/Electricaltransition, E/O, Electrical/Optical transition), PCM divides multiple connection module, circuit (1+1) automatic switchover module.Photoelectricity/electrooptic conversion module of the present invention, PCM divide multiple connection module and circuit automatic switchover module to be structure as a whole.The mutual connection of communicator of the present invention specifically couples together through circuit automatic switchover module, and transmission line can be latticed forms such as SDH network, PDH network, also can adopt the transmission line such as twisted-pair feeder, coaxial cable of laying.
Below specify concrete structure of the present invention and corresponding data communication flow process.As shown in Figure 2, for opto-electronic conversion of the present invention and PCM divide the implementation structure figure of multiple connection module.This structure includes:
Optical transceiver module: accomplish the conversion of the light signal/signal of telecommunication of twocouese.
The ring of light returns control module: data are carried out loopback test before sending; Make the optical interface signal under other the situation of transmission medium or selected transmission medium; With sending the receiving terminal of signal converting to oneself; Situation through the inspection data are sent and received judges whether the port working state is normal, to guarantee the transmission quality of data.The ring of light returns the loopback control command that control module can be controlled by simultaneously far-end, to make things convenient for the opening of equipment and circuit, fault detect and maintenance.
Coding and clock selection module: accomplish setting and selection control to type of coding, signal rate and clock mode according to dissimilar low speed.The master and slave pattern of type of coding, signal rate and the clock of light signal is set; From input signal, extract actual clock signal, offer " data decode " module as decode clock.Under the mode of master clock; System clock is produced by this module voluntarily; And to the pcm interface direction speed to be provided be the clock signal of 2M, provides to light transmission interface direction that to be synchronized with clock and the speed that this module produces voluntarily be the low-speed clock of optical interface speed.Under the mode of clock, provide to the pcm interface direction to be synchronized with the light input interface and speed is the clock signal of 2M; Provide to light transmission interface direction and to be synchronized with the 2M input interface and speed is the low-speed clock of optical interface speed.The present invention is when selecting different interface rates, and the low speed data code stream is to be inserted among each time slot of framing 2M through the mode that evenly interleaves.All the other time slots transmit the information such as webmaster, control except being used for, and unnecessary time slot does not re-use.
Photodissociation sign indicating number, Clock Extraction module: under the control of " coding and clock selection module ", accomplish from the Clock Extraction of the input signal of optical interface input direction and the function that data are decoded.
Light coding module: under the control of " coding and clock selection module ", accomplish the function of encoding to from the data of the input signal of PCM direction.
Send out buffer module: under the control of the actual low-speed clock signal that extracts, the data from the light input interface are carried out buffer-stored; Simultaneously under the control of the 2M clock that is synchronized with system clock, to PCM direction dateout.
Receive buffer module: under control, to storing from the data of pcm interface direction from PCM direction clock; Simultaneously under the control of the low-speed clock signal that is synchronized with system clock, to optical interface direction sense data.
PCM Multiplexing module: accomplish low speed data to meeting the G.704 data transaction of form.Idiographic flow is following:
Pressing G.704, data format produces characteristics such as frame, multi-frame, Si;
Send out at 2M under the control of clock, low speed data is inserted in the G.704 one-tenth frame data stream of generation, form G.704 data flow;
Above-mentioned G.704 data flow is carried out verification by CRC-4 verification rule, and produce check code word; The check code word is inserted in the relevant position of data flow G.704.
The PCM demultiplexing module: accomplishing G.704, the data of form arrive the low speed data conversion.Idiographic flow is following:
Under the control of the clock that extracts in the 2M input port,
Carrying out G.704, frame synchronization, multi-frame reach the CRC-4 verification operation synchronously.
Go out low speed data from extracting data G.704.
PCM loopback control module: can realize the loopback control of both direction, to support the loopback test of PCM transmission channel and transmission line.Under the control of PCM loopback control signal, can realize the loopback of 2M interface side, can realize that also PCM divides the loopback of multiplexing side.
2M Clock Extraction module: accomplish and from the 2M input signal, extract the 2M clock.Harmless circuit switching of the present invention is to adjust through the propagation delay time of carrying out that signal is produced when transmit in different paths in network to accomplish.When sending data,, be divided into two-way and be sent to different transmission systems with multiplexing back 2Mb/S signal adding markers and after recomputating the CRC-4 coding.The time scale information that inserts is for the receiving terminal two paths of data can be alignd.Below specify.
As shown in Figure 3, the data transmission blocks after PCM of the present invention is multiplexing comprises the markers insert module that is used for markers is inserted multiplex data, is used for CRC-4 is inserted the CRC insert module of multiplex data.The markers insert module is carried out deblocking with the signal after multiplexing, adds different label (the label here is meant time tag) for each piece.This label can be inserted in the Sa bit or certain idle time slot G.704.Because output 1 is identical with the content of output 2; At receiving terminal, can think that the data block with same label is exactly same blocks of data, promptly only with the label of comparing two paths of signals; And, just can know whether two data blocks of this two-way reception signal are identical data blocks without the comparison information content.
As shown in Figure 4; Circuit automatic switchover module of the present invention includes the buffer that is used for the transceive data storage, the alignment of data module that is used for the multiplex data of two-way at least that receives is carried out markers extraction and alignment of data; Be used for the 2M signal is carried out the chock smotthing module of chock smotthing; Be used for two-way multiplex data is at least carried out the transmission quality analysis module that transmission quality is analyzed, be used to carry out the circuit handover module that switches between the two-way multiplex data transmission line at least.
Below to specify circuit automatic switchover step of the present invention.
Storage of the present invention and alignment at first are described.For 2 road transmission line data block transmitted, 2 buffers (RAM) are set respectively store.As shown in Figure 5, in data block, deposit in successively according to the different time label on the respective data blocks in the different address sections of respective cache device each transmission line, the less data block of time tag deposits forward address section in.As the data of the transmission line 1 that receives deposit buffer 1 (RAM1) in, have time tag, and the data block of " 1 " deposits the 1st address section in, and the data block that will have label " 2 " deposits the 2nd address section in, and the like.The storage organization of 2 buffers is identical, to make things convenient for reading and aliging of data.The buffer here can be the first in first out buffer.Time tag also can adopt sequence number to replace.
Mode by write data reads 2 data blocks in the buffer respectively, and judges whether the label of two data blocks of extracting is identical, if then extraction again inequality; The present invention carries out quality analysis to 2 circuit-switched data of extracting, judge transmission quality best a road, select in the buffer of this circuit-switched data of storage corresponding data as dateout.Transmission quality analysis of the present invention comprises: the alarm of each transmission line data blocks stored being carried out dropout, alarm indication, frame remote alarm, multi-frame remote alarm, OOF etc. is respectively checked; Simultaneously the bit error code of each transmission line data blocks stored, the performances such as error code, frame error code, CRC error code of encoding are checked, can be carried out that also M2100 analyzes etc.The data that the present invention adopts comprehensive judgment mode decision desire to select.For example can rule of thumb the proportion weights be set, calculate the data transmission quality of each transmission line according to the weights that are provided with for above-mentioned each parameter, and with this as basis for estimation.
If all there is not error code after the quality analysis in the two-way, the identical address position of two buffers after the storage should deposit identical data in like this.Two paths of data has realized the alignment in memory, only need select during output from buffer 1 or buffer 2 extraction data, even between two buffers, switch back and forth, dateout can not occur mistake yet and promptly damage." output " signal send PCM to carry out demultiplexing.
When alarm takes place in transmission; Given birth to LOS (dropout) as riches all the way, AIS (alarm indication), LOF (LOF) alarm; Make this circuit-switched data can not use fully; Then total output only needs from the RAM on another road, fetch data fully output, just switched to another road, till that road that alarm has taken place is recovered normally.This is the process that alarm is switched.If two paths of signals is alarm not, but error code has taken place, if 1 tunnel " 4 " blocks of data has error code; 2 tunnel " 5 " blocks of data has error code, switches to 2 the tunnel in the time of then should exporting the 4th blocks of data, read data from RAM2; In the time should exporting the 5th blocks of data, switch to 1 the tunnel, read data from RAM1.So just avoided taking place the data segment of error code.Because the two-way transmission is two fully independently transmission systems, the probability that error code takes place this two-way simultaneously reduces greatly, and therefore, the probability that error code takes place in total output also reduces greatly, therefore can improve error performance.Error code occurring is the foundation of switching.
Just produce switching if occurred single error code in the data block, be called bit error code and switch.(like 10e-4,10e-6) just switch, then be called the grade error code and switch, the grade error code switches and can only when one tunnel transmission performance drops to the grade of setting, could switch, and therefore can not improve the circuit error code class if this road error code reaches certain rank.Can select bit error code to switch or the switching of grade error code according to different customer requirements.
Bit error code switch to require to judge fast, switches fast, the control at the interval of total output read pointer and two write pointers is required very accurate, therefore switches difficult realization than the grade error code.Through selecting read data from which RAM, can realize the data switching between two RAM.Align just because of two-way, just make this technology can realize that not damaged switches.
Though data have realized undamaged switching,, still can cause to seriously influence to the line signal quality if clock does not switch accordingly.Clock switches and to occur in a certain road LOS takes place, AIS, and the LOF alarm makes when this road clock signal can not correct extraction.At two paths of signals all just often, total output be synchronized to 1 the tunnel still 2 tunnel clock all be fine.Suppose current total output clock synchronization and 1 tunnel, at this moment, the 1 road alarm has taken place, and 1 road clock is no longer available, should switch to 2 the tunnel.If be directly switch to 2 the tunnel, because the two-way clock phase is different, will inevitably cause between the two-way to differ, directly switching can cause serious phase place damage and the output signal is sustained damage.As shown in Figure 6, the present invention also is provided with corresponding phase-locked loop, and the output clock after the switching can not undergone mutation, thereby makes the output signal injury-free.
Photoelectricity/electrooptic conversion module of the present invention, PCM divide multiple connection module and circuit automatic switchover module clock synchronization, and photoelectricity/electrooptic conversion module and PCM divide the multiple connection module shared same loopback control module.
Certainly; The present invention also can have other various embodiments; Under the situation that does not deviate from spirit of the present invention and essence thereof; Those skilled in the art work as can make various corresponding changes and distortion according to the present invention, but these corresponding changes and distortion all should belong to the protection range of the appended claim of the present invention.
Claims (9)
1. a low speed optical interface is characterized in that to the method for the multiplexing of 2M transmission line with the protection switching this method may further comprise the steps:
A, forwarding step:
(1) receives the low speed light signal of low speed optical interface input, this low speed light signal is carried out opto-electronic conversion and Clock Extraction, utilize the clock that extracts the data row cache of going forward side by side of decoding;
(2) utilize the 2M clock to generate the 2M data flow of ITU-TG.704 regulation: under the control of 2M clock; According to the speed of low speed data will decode and buffer memory after low speed data be inserted into the ITU-TG.704 2M data format that forms standard in the 2M data flow of said ITU-TG.704 regulation, thereby completion multiplexing to low speed data;
(3) said 2M data flow is carried out verification by corresponding CRC rule, and produce check results, this check results is inserted into the CRC position of said 2M data flow, and send these data simultaneously through two-way transmission line at least;
B, receiving step:
(1) the said 2M of two-way at least data flow is carried out Clock Extraction after receiving the 2M of the two-way at least data flow of 2M interface input; Utilize the 2M data in this said 2M of two-way at least data flow of 2M Clock Extraction of extracting; And carry out frame synchronization and CRC; Carry out the transmission quality analysis then, select a road best 2M data flow, from this road best 2M data flow, extract low speed data and promptly demultiplex into low speed data according to the quality analysis result;
(2) under the control of low-speed clock, the low speed data behind the demultiplexing is carried out respective coding;
(3) low speed data behind the coding is carried out electricity/light conversion, at the light signal that passes through under the control of low-speed clock after the low speed optical interface sends this conversion;
This method also comprises step: when after multiplexing to low speed data, proceeding to the transmission of few two-way; Data-signal with this after multiplexing carries out piecemeal; Add the different time label for each data block, with identical data in the order of nominal data piece and the different transmission line; When receiving terminal is handled these different track datas that receive; Can think that the data block with identical time tag is exactly same blocks of data; Promptly only can confirm with the label of comparison two paths of signals whether the data block of two-way is identical data block; So that two paths of signals aligns, be beneficial to circuit and carry out undamaged switching.
2. the method that low speed optical interface according to claim 1 switches to the multiplexing of 2M transmission line and protection; It is characterized in that; Said low speed data is inserted in the 2M data flow of ITU-TG.704 regulation, is specially: the low speed data code stream is inserted among each time slot in the 2M data flow after the framing through the mode that evenly interleaves; Remaining time slots is used for communicating control information.
3. the method that low speed optical interface according to claim 1 switches to the multiplexing of 2M transmission line and protection; It is characterized in that; This method also comprises the loopback test step of the loopback test and the 2M interface side of said low speed optical interface side; Be specially: with the signal of said low speed optical interface or 2M interface under transmission medium that is provided with or situation through selected transmission medium; With sending the receiving terminal of signal converting, judge through the situation that the inspection data are sent and received whether the port working state is normal, to guarantee the transmission quality of data to oneself; The loopback control command that also is controlled by far-end simultaneously is to make things convenient for the opening of equipment and circuit, fault detect and maintenance.
4. the method that low speed optical interface according to claim 1 switches to the multiplexing of 2M transmission line and protection; It is characterized in that; In the said receiving step data that receive are carried out the transmission quality analysis, be specially: the two paths of data at least that will receive stores into respectively in the different buffers by the difference of transmission line, and stores into successively in the corresponding address of buffer by the time tag of data block; Extract the data block that has identical time tag in each buffer; Each circuit-switched data piece to extracting carries out quality analysis, judge transmission quality best a road, select this top-quality data block as dateout.
5. the method for switching to the multiplexing of 2M transmission line and protection according to the described low speed optical interface of arbitrary claim in the claim 1 to 4 is characterized in that, the 2M data flow is specially the 2.048MbPs data of the E1 interface standard that meets the ITU-TG.704 suggestion.
6. a low speed optical interface is to the multiplexing of 2M transmission line and protection device for switching; Include the photoelectricity/electrooptic conversion module based on low-speed interface, the PCM that are electrically connected successively and divide multiple connection module, circuit automatic switchover module; Said photoelectricity/electrooptic conversion module divides the multiple connection module to be connected with PCM, and said PCM divides the multiple connection module to be connected with said circuit automatic switchover module; It is characterized in that; Said photoelectricity/electrooptic conversion module includes the light signal input/output module that is used for light signal input and output, opto-electronic conversion and inverse conversion; Utilize corresponding clock to carry out the coding/decoding module of light signal encoding and decoding; The clock of more than one frequency pulses can be provided, be used for the loopback control module of signal loopback test, be used for the buffer of metadata cache; Said PCM divides the multiple connection module to include to be used for low speed data is multiplexed into the 2M data flow and the 2M data flow is demultiplexed into the multiplexing and demultiplexing module of low speed data; Be used for markers is inserted into the markers insert module of the 2M data flow after multiplexing, be used for CRC is inserted into the CRC insert module of the 2M data flow after multiplexing; Said circuit automatic switchover module includes the alignment of data module that is used for the 2M of the two-way at least multiplexed data flow that receives is carried out markers extraction and alignment of data; Be used for the 2M data flow is carried out the chock smotthing module of chock smotthing; Be used for the said 2M of two-way at least multiplexed data flow is carried out the transmission quality analysis module that transmission quality is analyzed, be used to carry out the circuit handover module that switches between the said 2M of the two-way at least multiplexed data flow transmission line; Said photoelectricity/electrooptic conversion module, PCM divide multiple connection module and circuit automatic switchover module clock synchronization, and said photoelectricity/electrooptic conversion module and PCM divide the multiple connection module shared same loopback control module;
Said photoelectricity/electrooptic conversion module receives the low speed light signal of low speed optical interface input, and this low speed light signal is carried out opto-electronic conversion and Clock Extraction, utilizes the clock that extracts to the data row cache of going forward side by side of decoding;
Said PCM divides the multiple connection module to utilize the 2M clock to generate the 2M data flow of ITU-TG.704 regulation: under the control of 2M clock; According to the speed of low speed data will decode and buffer memory after low speed data be inserted into the ITU-TG.7042M data format that forms standard in the 2M data flow of said ITU-TG.704 regulation, thereby completion multiplexing to low speed data; Said 2M data flow is carried out verification by corresponding CRC rule, and produce check results, this check results is inserted into the CRC position of said 2M data flow, and send these data simultaneously through two-way transmission line at least;
Said circuit automatic switchover module is carried out Clock Extraction to the said 2M of two-way at least data flow after receiving the 2M of the two-way at least data flow of 2M interface input; Utilize the 2M data in this said 2M of two-way at least data flow of 2M Clock Extraction of extracting; And carry out frame synchronization and CRC; Carry out the transmission quality analysis then; Select a road best 2M data flow according to the quality analysis result, said PCM divides the multiple connection module from this road best 2M data flow, to extract low speed data promptly to demultiplex into low speed data; Said photoelectricity/electrooptic conversion module is under the control of low-speed clock; Low speed data behind the demultiplexing is carried out respective coding; Low speed data behind the coding is carried out electricity/light conversion, at the light signal that passes through under the control of low-speed clock after the low speed optical interface sends this conversion;
When said markers insert module proceeded to the transmission of few two-way after multiplexing to low speed data, the data-signal with this after multiplexing carried out piecemeal, adds the different time label for each data block, with identical data in the order of nominal data piece and the different transmission line; When receiving terminal is handled these different track datas that receive; Can think that the data block with identical time tag is exactly same blocks of data; Promptly only can confirm with the label of comparison two paths of signals whether the data block of two-way is identical data block; So that two paths of signals aligns, be beneficial to circuit and carry out undamaged switching.
7. low speed optical interface according to claim 6 is characterized in that to the multiplexing of 2M transmission line and protection device for switching said photoelectricity/electrooptic conversion module, PCM divide multiple connection module and circuit automatic switchover module to be structure as a whole.
8. low speed optical interface according to claim 6 is characterized in that to the multiplexing of 2M transmission line and protection device for switching said transmission line can be SDH network, PDH network or directly lays corresponding transmission line.
According to the described low speed optical interface of arbitrary claim in the claim 6 to 8 to the multiplexing of 2M transmission line with the protection device for switching, it is characterized in that the 2M data flow is specially the 2.048MbPs data that meet the E1 interface standard; The buffer of storage reception multiplex data is provided with by the number of transmission line, and said buffer is the first in first out buffer.
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| CN102882592B (en) * | 2012-09-26 | 2015-08-19 | 武汉邮电科学研究院 | Be applied to 2M light signal transparent transmission device and the method for SDH network |
| CN107566035A (en) * | 2016-06-30 | 2018-01-09 | 中兴通讯股份有限公司 | Optical fiber connecting detection method, network management server and receiving terminal network element |
| CN107343006A (en) * | 2017-07-13 | 2017-11-10 | 广州鼎飞航空科技有限公司 | A kind of method of transmitting video data and device |
| CN107425911B (en) * | 2017-07-27 | 2020-11-24 | 南开大学 | Communication terminal visible light data transmission device and transmission method |
| EP3502817A1 (en) * | 2017-12-19 | 2019-06-26 | ABB Schweiz AG | Method for facilitating control system testing and simulation |
| CN108390745A (en) * | 2018-02-05 | 2018-08-10 | 柳州达迪通信技术股份有限公司 | A kind of lossless switching method of relay protection communication 2M signals |
| CN108732692B (en) * | 2018-05-15 | 2019-08-20 | 国网浙江省电力有限公司 | A kind of photosignal automatic switching method |
| CN113422756B (en) * | 2021-05-26 | 2022-12-27 | 鹏城实验室 | Verification data transmission method, rate conversion device and verification data transmission system |
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