RU2423796C1 - Method of controlling data stream transfer rate and device for realising said method - Google Patents

Abstract

FIELD: information technology. ^ SUBSTANCE: in the method of controlling data stream transfer rate, the effect of stimulated Raman scattering with the required length of the fibre-optic communication line is minimised, owing to which the said technical result is achieved by increasing the value of the optical signal/noise ratio at the input of the photodetector and rational distribution of data streams on spectral channels in case of failure of one of the spectral channels. ^ EFFECT: high reliability of transmitting an optical signal. ^ 2 cl, 3 dwg

Description

The proposed inventions are united by a single inventive concept, relate to the field of multi-channel fiber-optic transmission systems, in particular to systems using spectral channel multiplexing.

There is a method of increasing the capacity of a fiber-optic channel, which consists in transmitting several digital streams on a single fiber on different optical carriers within the transparency region of a linear fiber, called spectral channel multiplexing - QMS (Brackett C. A. "Dense WDM Networks." Fourteenth European Conference on Optical Communications (ECOC 88), 11-15 Sept. 1988 Techn. Digest, part I, p. 543, Brighton, UK). The method is characterized in that each pair of terminals of the fiber optic path — transmitting and receiving — uses a constant operating wavelength to transmit a digital stream at a constant speed in each spectral channel. To change the correspondent terminal, a change in the working wavelength can be used, but the total number of channels simultaneously transmitted through the system is limited by the number of multiplexed optical carriers, while the transmission rate of information flows remains constant.

Known devices for transmitting signals over fiber-optic communication lines (see, for example, RF Patent No. 2248087, 1999, RF Patent No. 2204211, 2001). Known analogues contain sources of optical radiation, optical multiplexers / demultiplexers, transmission medium of an optical signal, which is used as an optical fiber, photodetectors.

A common disadvantage of analogues is the impossibility of changing the transmission rate of information flows in a particular given spectral channel.

, где

- число размещений из n элементов по m, модулируют излучения m канальных оптических передатчиков, различающихся оптическими длинами волн, тактовым набором m СВЧ поднесущих с одновременным вводом в оптический сигнал информации о тактовой частоте цифровой синхронной системы передачи, передают сигналы различных цифровых каналов на любой из используемых рабочих оптических длин волн в соответствии с распределением рабочих длин волн контролируемым блоком управления переключением используемых оптических длин волн между передающими и приемными терминалами систем связи, объединяют спектрально-разнесенные выходные оптические сигналы всех m канальных оптических передатчиков в групповой оптический линейный сигнал, передают группового оптический линейный сигнал по линейному оптическому тракту, разделяют в приемном терминале групповой оптический сигнал на m составляющих по признаку различия оптических длин волн, детектируют каждый составляющий оптического сигнала канальным фотоприемным устройством, определяют, какое значение СВЧ поднесущей было передано по каждому из m оптических каналов на данном тактовом интервале с одновременным выделением тактовой частоты цифровой синхронной системы передачи, формируют эквивалент тактового набора m СВЧ поднесущих, аналогичного полученному в результате кодирования входной совокупности N символов на передающем терминале, декодируют эквивалент тактового набора m СВЧ поднесущих с формированием совокупности N двоичных символов, распределенных в течение данного тактового интервала по N выходным каналам приемного терминала так же, как на входе передающего терминала.The closest in technical essence to the claimed method and selected as a prototype is a method of transmitting signals of synchronous digital fiber optic systems by the method of spectral-code multiplexing (RF patent №2124812 from 01/10/1999), which consists in the fact that the set of N input characters. An N-channel digital synchronous transmission system signal generated during each clock interval is encoded by a clock set of m microwave subcarriers from among m microwave subcarriers generated by a subcarrier synthesizer, m, n and N being related by

where

- the number of arrangements of n elements in m, modulate the radiation of m channel optical transmitters, differing in optical wavelengths, with a clock set of m microwave subcarriers with simultaneous input of information about the clock frequency of the digital synchronous transmission system into the optical signal, transmit signals of various digital channels to any of the used working optical wavelengths in accordance with the distribution of working wavelengths by a controlled control unit for switching the used optical wavelengths between transmitting and receiving by the terminals of communication systems, combine the spectrally-spaced output optical signals of all m channel optical transmitters into a group optical linear signal, transmit a group optical linear signal along a linear optical path, divide the group optical signal into m components in the receiving terminal according to the difference in optical wavelengths, each component of the optical signal is detected by the channel photodetector; it is determined which value of the microwave subcarrier was transmitted for each of m opt channels at a given time interval with simultaneous allocation of the clock frequency of the digital synchronous transmission system, form the equivalent of a clock set of m microwave subcarriers similar to that obtained by encoding the input set of N symbols at the transmitting terminal, decode the equivalent of a clock set of m microwave subcarriers with the formation of a set of N binary symbols distributed over a given clock interval over the N output channels of the receiving terminal in the same way as at the input of the transmitting terminal.

Of the known closest analogue (prototype) in its technical essence of the claimed device is a device according to the patent of the Russian Federation No. 2148812 of 01/10/1999.

The prototype device for its implementation includes a transmitting terminal, which includes a signal input device for the N-channel synchronous digital transmission system, an encoder switch, a microwave subcarrier synthesizer, m channel optical transmitters with spaced wavelengths, a device for combining spectrally-spaced channels , a linear optical path, while through the input device to the terminal of the signals of the N-channel synchronous digital transmission system, the inputs of N synchronous digital channels are connected to N information to the inputs of the encoder-switch, the input of the switching signal is connected to the switching input of the encoder-switch, the input of the clock frequency is connected to the clock inputs of the encoder-switch, microwave subcarrier synthesizer and channel optical transmitters, n microwave outputs of the microwave subcarrier synthesizer are connected to n microwave inputs of the encoder-switch , m microwave outputs of the encoder-switch are connected respectively to the modulator inputs of m channel optical transmitters, the optical outputs of m channel optical transmitters are connected to m inputs of the device the spectral diversity optical channels, the output of which is connected to the input of the linear optical path, as well as a receiving terminal, which contains a spectral diversity optical channel separation device, m channel photodetectors, a clock synchronization device, a microwave subcarrier synthesizer, m channel subcarrier determination devices, decoder, switch signal decoder, synchronous digital channel switch controller, synchronous digital channel switch, terminal output device N with signals and clock frequency of a synchronous digital transmission system, while the output of the linear optical path is connected to the input of the separation device for spectrally separated optical channels, m outputs of which are connected respectively to the optical inputs of m channel photodetectors, the first microwave outputs of which are connected respectively to the information microwave inputs of the channel subcarrier detection devices, and the second microwave outputs are connected to the inputs of the clock synchronization device, the outputs of which are connected to the clock inputs synchronization of subcarrier determination devices, a decoder, a device for outputting N signals from the terminal and the clock frequency of the synchronous digital transmission system and the clock input of the microwave subcarrier synthesizer, the microwave outputs of which are connected in parallel to the microwave subcarrier inputs in all m subcarrier determination devices, the outputs of the subcarrier determination devices are connected respectively, to m at n information inputs of the decoder, while the decoder includes a device for outputting excess clock sets of microwave subcarriers, outputs to connected to the inputs of the decoder of the switching signals, the decoder output is connected to the input of the controller of the synchronous digital channel switch, the controller output is connected to the control input of this switch, N information inputs of which are connected to N information outputs of the decoder, N information outputs are connected to N inputs of the output device from the receiver terminal synchronous digital channels.

The disadvantages of the prototype method and the device that implements it are as follows:

1) the transmission through the spectral channels of information flows of the synchronous digital hierarchy (SDH) only with the same and constant speed in each spectral channel;

2) at signal transmission speeds above 2.5 Gbit / s, the reliability of the transmission of optical signals decreases as a result of the influence of the effect of stimulated Raman (Raman) scattering.

In the event of failure of one or more spectral channels of the main optical path, it may be necessary to redistribute the load to another spectral channel of the same path, which will require an increase in the transmission rate of information through this spectral channel. Also, the problem may arise of increasing the transmission speed in a particular spectral channel, while maintaining the same transmission rate of information flows in the remaining spectral channels. It is obvious that an increase in the transmission rate will lead to a decrease in the reliability of the transmission in a given spectral channel.

It is known that the power introduced into an optical fiber is related to the transmission speed of the optical signal as follows (Saitov I.A., Schekotikhin V.M. Theoretical Foundations of Building Optical-Range Communication Facilities. Textbook. - Eagle: Academy of Federal Security Service of Russia, 2008. - 490 s):

where P _{νν, m} is the power of the optical signal of the m-th spectral channel, introduced into the optical fiber, mW;

P _istm is the power of the optical radiation source radiated into the m-th spectral channel, mW;

B - transfer rate, Gbit / s;

χ is the coefficient of the dependence of the signal power on the modulation speed, due to the type of external modulator.

Thus, with an increase in the transmission rate of the digital information stream in a particular spectral channel, the power introduced into the optical fiber for a given spectral channel will change, which will affect the intensity of stimulated Raman scattering (SRS), therefore, the reliability of the transmission of the optical signal for a given length of the communication line .

In addition, the stimulated Raman scattering has a dominant effect on the reliability of optical signal transmission at optical signal transmission rates of more than 2.5 Gbit / s (Ovchinnikov A.A., Svetikov Yu.V., Sinev S.G. Method for optimizing the parameters of the linear FOTS path with spectral separation // Telecommunications - 1992. - No. 12. - S.19-21).

SRS is a threshold effect, therefore, to prevent its manifestation, the value of the optical signal power P _νν introduced into the optical fiber should be lower than a certain threshold value of the input power P _por calculated for a specific type of optical fiber (Agraval G. Nonlinear fiber optics. - M .: Mir , 1996 .-- 234 p.). If the intensity of the power input into the optical fiber exceeds a certain threshold value P _νν > P _por , then the intensity of the Raman noise increases so quickly that most of the energy of the radiation input into the optical fiber passes into it. In this case, the optical signal / noise ratio in the long-wavelength spectral channels of the fiber-optic linear path will decrease, and therefore, the reliability of the transmission of the optical signal in them will deteriorate.

The reliability of optical signal transmission is usually estimated by such an indicator as the probability of a bit error, which can be calculated by measuring the optical signal-to-noise ratio at the input of a photodetector (Zarkevich E.A., Sklyarov OK, Ustinov S.A. Testing and monitoring of parameters in WDM networks. Continuous monitoring and measurement of system parameters in WDM networks // Technologies and means of communication. - No. 2, 2002; No. 3, 2002.):

where Ho _m is the optical signal-to-noise ratio at the input of the photodetector of the m-th spectral channel, dBm;

P _sm is the power of the optical signal at the input of the photodetector of the m-th spectral channel, mW;

P _Σm is the total power of the information signal and noise of the m-th spectral channel, mW;

P _qm is the quantum noise power of optical transmitters with spaced wavelengths of the m-th spectral channel, mW.

The objective of the patented group of inventions is a method for controlling the transmission rate of an information stream in a given spectral channel and a device for its implementation, which allows to obtain an increase in the reliability of transmission of an optical signal (increasing the value of the optical signal / noise ratio at the input of a photodetector) by minimizing the effect of stimulated Raman scattering when the required length of the fiber optic communication line.

, где

- число размещений из n элементов по m. Причем модулируют излучения m канальных оптических передатчиков, различающихся оптическими длинами волн, тактовым набором m СВЧ поднесущих с одновременным вводом в оптический сигнал информации о тактовой частоте цифровой системы передачи. Сигналы различных цифровых каналов передают на конкретной из используемых рабочих оптических длин волн в соответствии с распределением рабочих длин волн контролируемым блоком управления переключением используемых оптических длин волн между передающими и приемными терминалами систем связи. Затем объединяют спектрально-разнесенные выходные оптические сигналы всех m канальных оптических передатчиков в групповой оптический линейный сигнал. Групповой оптический линейный сигнал передают по линейному оптическому тракту и в приемном терминале разделяют на m составляющих по признаку различия оптических длин волн. Каждую составляющую оптического сигнала детектируют канальным фотоприемным устройством. Определяют, какое значение СВЧ поднесущей было передано по каждому из m оптических каналов на данном тактовом интервале. При этом одновременно выделяют тактовую частоту цифровой системы передачи, формируют эквивалент тактового набора m СВЧ поднесущих, аналогичного полученному в результате кодирования входной совокупности N символов на передающем терминале. Затем декодируют эквивалент тактового набора m СВЧ поднесущих с формированием совокупности N двоичных символов, распределенных в течение данного тактового интервала по N выходным каналам приемного терминала так же, как на входе передающего терминала. При этом дополнительно формируют сигнал коммутации таким образом, что при получении сигнала об ухудшении значения отношения оптический сигнал-шум в каком-либо спектральном канале осуществляют перераспределение информационного потока из этого спектрального канала по остальным, либо в случае необходимости увеличения скорости в конкретно заданном спектральном канале формируют соответствующее управляющее воздействие. Кроме того, с одновременным выделением тактовой частоты цифровой системы передачи и сигналов коммутации, осуществляют контроль значения отношения оптический сигнал-шум и в случае отклонения от нормы в каком-либо спектральном канале передают соответствующий сигнал по обратному каналу связи для формирования сигнала коммутации.This problem is solved by a method of controlling the transmission rate of information flows, namely, that the set of N input symbols of the N-channel signal of the digital synchronous transmission system generated during each clock interval is encoded by a clock set of m microwave subcarriers from among n microwave subcarriers generated by the synthesizer Microwave subcarriers. Moreover, m, n and N are related by

where

- the number of placements of n elements in m. Moreover, the emissions of m channel optical transmitters, differing in optical wavelengths, are modulated by a clock set of m microwave subcarriers with simultaneous input of information about the clock frequency of the digital transmission system into the optical signal. The signals of various digital channels are transmitted on a specific of the used optical wavelengths in accordance with the distribution of the operating wavelengths by a controlled control unit for switching the used optical wavelengths between the transmitting and receiving terminals of communication systems. Then, the spectrally-spaced output optical signals of all m channel optical transmitters are combined into a group optical linear signal. The group optical linear signal is transmitted along the linear optical path and is divided into m components in the receiving terminal according to the difference in optical wavelengths. Each component of the optical signal is detected by a channel photodetector. Determine what value of the microwave subcarrier was transmitted on each of the m optical channels in a given clock interval. At the same time, the clock frequency of the digital transmission system is isolated, the equivalent of the clock set m of microwave subcarriers is formed, similar to that obtained by encoding an input set of N symbols at the transmitting terminal. Then, the equivalent of the clock set of m microwave subcarriers is decoded to form a set of N binary symbols distributed over the N output channels of the receiving terminal during a given clock interval, as well as at the input of the transmitting terminal. At the same time, a switching signal is additionally formed in such a way that upon receipt of a signal of deterioration of the optical signal-to-noise ratio in a spectral channel, the information flow from this spectral channel is redistributed over the others, or if it is necessary to increase the speed in a specific spectral channel appropriate control action. In addition, with the simultaneous allocation of the clock frequency of the digital transmission system and the switching signals, the optical signal-to-noise ratio is monitored and, in the event of a deviation from the norm in any spectral channel, the corresponding signal is transmitted via the reverse communication channel to form the switching signal.

A new set of essential features allows achieving the indicated technical result due to the fact that the optical signal-to-noise ratio is controlled in each spectral channel and, in case of deviation from the norm, the corresponding switching signal is generated for the distribution of digital streams through other spectral channels, or, if necessary, to increase the transmission speed in a particular spectral channel, while maintaining the transmission speed in other spectral channels, the corresponding control signal ulyatorami channel optical transmitters.

This problem is solved in that the transmission rate control device comprising a transmitting terminal, which includes an encoder switch, a microwave subcarrier synthesizer, m channel optical transmitters with different operating wavelengths, a spectral diversity channel combining device, a linear optical path. The inputs of N digital channels are connected to the N information inputs of the encoder switch. The input of the switching signal is connected to the switching input of the encoder-switch, the clock input is connected to the clock inputs of the encoder-switch, microwave subcarrier synthesizer and channel optical transmitters, n microwave outputs of the microwave subcarrier synthesizer are connected to n microwave inputs of the encoder-switch, m microwave encoder outputs the switches are connected respectively to the inputs of the modulators m channel optical transmitters. The optical outputs of n channel optical transmitters are connected to the m inputs of a device for combining spectrally separated optical channels, the output of which is connected to the input of a linear optical path. A receiving terminal, which contains a device for separating spectrally-separated optical channels, m channel photodetectors, a clock synchronization device, a microwave subcarrier synthesizer, channel subcarrier determining devices, a decoder. The output of the linear optical path is connected to the input of the separation device for spectrally separated optical channels, m outputs of which are connected respectively to the optical inputs of the channel m photodetector devices. The first microwave outputs of the channel m photodetectors which are connected respectively to the information microwave inputs of the subcarrier detection devices, and the second microwave outputs are connected to the inputs of the clock frequency. The outputs of the clock device are connected to the clock inputs of the subcarrier detection devices, the decoder, and the clock input of the microwave subcarrier synthesizer. The outputs of the microwave subcarrier synthesizer are connected in parallel to the inputs of the microwave subcarriers in all m subcarrier determination devices. The outputs of the subcarrier determination devices are connected respectively to m through n information inputs of the decoder. The decoder includes an output device for excess clock sets of microwave subcarriers, the outputs of which are connected to the inputs of the decoder of the switching signals. The decoder of the switching signals is connected to the input of the controller of the switch of digital channels, the outputs of which are connected to the inputs of the switch of digital channels. In addition, a switching control circuit, an input device for the terminal of N-channel digital information flows, clock frequency and switching signals, a control circuit for optical channel transmitters, an optical spectrum analyzer, a feedback channel, a digital channel switch controller, a digital channel switch, a signal output device are introduced N-channel digital information streams and clock frequency. Moreover, one output of the switching control circuit is connected to an input for inputting a switching signal of the input device to the terminal N of information flows, clock frequency and signals. The second output of the switching control circuit is connected to the second input of the control channel optical transmitters. In this case, N information flows are connected to an input device to the terminal of N-channel information flows, clock frequency and switching signals, information outputs of which are connected to N information inputs of the encoder-switch, and the switching signal is connected to the switching input of the encoder-switch and to the input of the control circuit channel optical transmitters. The outputs of the channel photodetectors are connected to the inputs of the optical spectrum analyzer, the output of which is connected via the feedback channel to the input of the switching control circuit. The output of the decoder of the switching signals is connected to the input of the controller of the switch of digital channels, the output of which is connected to the control input of the switch of digital channels. N information outputs of the digital channel switch are connected to N inputs of the terminal output device N synchronous information flows and clock frequency.

Thanks to a new set of essential features due to additionally introduced elements into the claimed device, the transmission rate of the information stream in the fiber-optic transmission system is implemented. At the same time, the effect of stimulated Raman scattering is minimized at the required length of the fiber-optic communication line.

The analysis of the prior art made it possible to establish that there are no analogues that are characterized by a combination of features identical to all the features of the claimed method and device for transmitting synchronous information flows. Therefore, each of the claimed inventions meets the condition of patentability “novelty”.

The search results for known solutions in this and related fields of technology in order to identify features that match the distinctive features of the prototypes of the claimed method and device showed that they do not follow explicitly from the prior art. The prior art also did not reveal the popularity of the influence provided by the essential features of each of the claimed inventions of the transformations on the achievement of the specified technical result. Therefore, the claimed invention meets the condition of patentability "inventive step".

The claimed objects of the invention are illustrated by drawings, in which:

figure 1 - structure of a device for transmitting information flows;

figure 2 - graphs of the relationship of the optical signal / noise from the length of the line with increasing transmission speed in the spectral channel No. 8 before and after optimizing the values of the power of the optical radiation introduced into the optical fiber.

The implementation of the claimed method is as follows. A set of N input symbols of the N-channel signal of the digital transmission system generated during each clock interval is supplied to the input of the transmitting terminal, encoded by a clock set of t microwave subcarriers from among n microwave subcarriers, modulated emissions of m channel optical transmitters differing in optical wavelengths, clock set m microwave subcarriers with simultaneous input into the optical signal of information about the clock frequency of the digital transmission system and switching signals, transmit signals of various digital channels and the used working optical wavelengths in accordance with the distribution of the working wavelengths by the controlled control unit for switching the used optical wavelengths between the transmitting and receiving terminals of communication systems, in the case of a decrease in the optical signal ratio noise in a particular spectral channel, the switching control circuit redistributes the incoming information over the spectral channels, forming it emits a switching signal for controlling the encoder-switch and supplies the corresponding control signals to the channel optical transmitter control circuit, which controls the channel optical transmitter modulators; in addition, the receiving terminal determines what value of the microwave subcarrier was transmitted for each of the m optical channels on this the clock interval with the simultaneous allocation of the clock frequency of the synchronous transmission system and switching signals, and after the formation of the equivalent clock set m microwave subcarriers decoded clock equivalent set of sub-carriers m and switching microwave signals with N form a plurality of binary symbols, distributed over a given clock interval of N output channels of the receiving terminal as well as the input to the transmission terminal.

The claimed method of controlling the transmission rate of information flows provides an increase in the reliability of the transmission of the optical signal by increasing the value of the optical signal / noise ratio at the input of the photodetector at the required length of the fiber-optic communication line.

The validity of the theoretical assumptions was checked using a simulation model of a fiber-optic transmission system with wavelength multiplexing under the following conditions:

- the number of spectral channels m = 8;

- length - 80 km;

- it is necessary to transmit 10 Giga-bitEthernet digital information streams having a transmission speed of 9.95 Gbit / s (10 GBase-W), however, information at a speed of 10.3125 Gbit / s (10 GBase-R) must be provided in spectral channel No. 8 ;

- to fulfill the requirements for the reliability of the transmission of the optical signal for the value of the ratio of the optical signal / noise should be at least But _rreb > 27 dBm.

The verification results are shown in Fig. 2, where Fig. 2a shows graphs of the dependence of the optical signal / noise ratio on the line length in the spectral channels to optimize the power values of the optical radiation introduced into the optical fiber. Analysis of the graphs shows that, due to the effect of stimulated Raman scattering, the shape of the graphs of the optical signal-to-noise ratio for long-wavelength spectral channels differs from the linear one, and with an increase in the transmission speed, spectral channel No. 8 does not satisfy the requirement for the reliability of transmission of the optical signal. On figb presents similar graphs after optimization of the optical signal power input into the optical fiber.

From the data presented it follows that after optimizing the values of the optical signal power input into the optical fiber and distributing the information flows over the spectral channels, the influence of stimulated Raman scattering on the reliability of the transmission of the optical signal decreases, while all spectral channels satisfy the requirement on the reliability of transmission, which indicates the possibility of achieving the claimed technical result.

The control device for the transmission rate of information flows (Fig. 1) contains a switching control circuit 1, input devices for terminal N of synchronous information flows, a clock frequency and switching signals 2, an encoder switch 3, microwave subcarrier synthesizers 4 _PER and 4 _PFP , control circuits channel optical transmitters 5, channel optical transmitters 6 ₁ -6 _m , devices for combining and separating spectrally-separated optical channels 7 _PER and 7 _PFP , optical path for transmitting a linear signal 8 (linear optical fiber), channel photodetectors 9 ₁ -9 _m , channel subcarrier determination devices 10 ₁ -10 _m clock synchronization device 11, optical spectrum analyzer 12, decoder 13, switching signal decoder 14, digital information stream switch controller 15, switch 16, device output signals N synchronous information flows, clock frequency and switching signals 17.

The elements are interconnected as follows (figure 1). The first output of the switching control circuit 1 is connected to the input of the input device to the terminal of the N-channel information flows, clock frequency and switching signals 2 for inputting the switching signal. The second output of the control circuit switching 1 is connected to the input of the control circuit of the channel optical transmitters 5. The information outputs of the input device to the terminal of the N-channel information flows, clock frequency and switching signals 2 are connected to the N information inputs of the encoder switch 3, the output of the input device to the terminal N synchronous information flows, clock frequency and switching signals for transmitting a switching signal is connected to the switching input of the encoder-switch 3 and the control channel optical by transmitters 5, the output for transmitting the clock frequency of the input device to the terminal of N-channel information flows, clock frequency and switching signals is connected to the clock inputs of the encoder switch 3, the microwave synthesizer subcarriers 4 _PER and channel optical transmitters 6 ₁ -6 _m , n microwave microwave synthesizer outputs subcarriers _PER 4 are connected to n inputs of microwave-coder switch, m microwave encoder-switch 3 outputs connected to inputs of the modulators m channel optical transmitters June ₁ -6 _m, m output optical channel send out to the control circuit ikami 5 are connected to the inputs of m-channel optical transmitters June ₁ -6 _m, the optical outputs of m-channel optical transmitters are connected to the m inputs of combining device spectrally separated optical channels 7 _PEN, whose output is connected to an input line of the optical path 8, the output of which is connected to the input separation device spectrally separated optical channels 7 _CSTR, m outputs of which are respectively connected to optical inputs of m-channel photodetectors September ₁ -9 _m, the first microwave outputs coupled with responsibly to information inputs of the microwave device determining subcarrier January ₁₀ -10 _m and the inputs of the optical spectrum analyzer 12 whose output is fed back is coupled to a corresponding input of the switching control circuit 1, and outputs the second microwave channel m photodetecting means 9 ₁ -9 _m connected to clock inputs of device 11, one output of which is connected to the input of the synthesizer microwave subcarrier _CSTR 4, another output connected to the clock inputs for determining a subcarrier channel device January ₁₀ -10 _m, the output ustroyst a clock 11 for transmitting the switching signal is coupled to the input of a decoder 13, n synthesizer microwave subcarrier 4prm outputs connected to the inputs of channel definition devices subcarrier January ₁₀ -10 _m, N outputs of each channel unit determining subcarrier January ₁₀ -10 _m of microwave outputs of which are connected in parallel to the inputs of the microwave subcarriers in all m subcarrier determination devices, the outputs of the subcarrier determination devices are connected respectively to m via n information inputs of the decoder 13, and devices are included in the decoder the output of redundant clock sets of microwave subcarriers, the outputs of which are connected to the inputs of the decoder of the switching signals 14, the output of the decoder of the switching signals is connected to the input of the controller of the digital channel switch 15, the output of which is connected to the control input of the switch of digital channels 16, N information inputs of which are connected to N information the outputs of the decoder 13, N information outputs connected to the N inputs of the output device from the terminal N synchronous information flows and clock frequency 17.

Switching control circuit 1 is intended for generating a switching signal and distributing synchronous information streams over functioning spectral channels in the event of a failure of any spectral channel, as well as generating a control signal for the control channel optical transmitters. The scheme of this device is known and can be implemented, as indicated, for example, in the book of Ionov S.V., Likhachev A.M., Nasurdinov E.F. New technologies for the construction of technical telecommunication systems. / Ed. A.A. Ivanova. - M., 1999 .-- S. 140-144.

The input device to the terminal N of synchronous information flows, clock frequency and switching signals 2 is intended for input into the terminal information flows of a synchronous digital hierarchy, clock signals and switching signals and can be constructed according to any known scheme, for example, see the book by Andreev I.A. ., Burdin V.A. and others. Construction and technical operation of fiber-optic communication lines. Textbook for high schools. / Ed. B.V. Popova. - M .: Radio and communications, 1995. - S.93-97.

Encoder switch 3 is a variation of a known encoding device that "displays" a combination of N input characters ("zeros" and "ones") generated during each clock interval, a combination of m specific microwave subcarriers (m × n ) Such a mapping can be performed by well-known circuitry techniques using high-speed electronic logic and microwave diode keys, as shown in the book by I.E. Nikulsky. Optical interfaces of digital switching stations and access networks. - M .: Technosphere, 2006. - S.113-118.

The microwave synthesizer subcarrier 4 _PER and 4 _PFP provides the formation of a grid of optical carrier information channels. The circuit of this device is known and can be implemented as indicated, for example, in the book of Young M. Optics and lasers, including fiber optics and optical waveguides: trans. from English - M.: Mir, 2005 .-- S.110-120.

The control circuit of channel optical transmitters 5 provides control of the radiation power of optical transmitters by implementing a well-known algorithm (I.A.Saytov et al. Program for optimizing the characteristics of the active components of a fiber-optic linear path under the dominant influence of stimulated Raman scattering on the reliability of optical signal transmission. Certificate of state registration of computer programs and databases No. 2008614569. - Application No. 20088613593 of 01.08.2008). The scheme of this device is known and can be implemented, as indicated in the book Sites I.A., Schekotikhin V.M. Theoretical foundations of the construction of optical range communications. Tutorial. - Eagle: Academy of the Federal Security Service of Russia, 2008. - P.232-237.

Channel optical transmitters 6 ₁ -6 _m are designed to convert an electrical signal at the input to an optical signal at the output. As a rule, in systems with wavelength-division multiplexing, laser diodes are used as channel optical transmitters. These devices are known and can be implemented, as it is stated in the book of Ivanov AB Fiber optics: components, transmission systems, measurements. - M .: Cyrus System Company, 1999. - P.134-143.

A device for combining spectrally-spaced optical channels 7 _PER performs the function of spectral multiplexing of optical signals and injects a group optical signal into the optical fiber. A device for separating spectrally-separated optical channels 6 of the _{PFP is} intended for demultiplexing the information stream. Schemes of devices for combining and separating spectrally separated optical channels are similar to each other, known and can be implemented, as indicated in the book Sites IA, Shchekotikhin VM Theoretical foundations of the construction of optical range communications. Tutorial. - Eagle: Academy of the Federal Security Service of Russia, 2008. - P.244 252, Fig.5.31.

Optical fiber 8 ₁ -8 _{M + 1} is the main element of optical communication cables and serves as a medium for the propagation of an optical signal. The manufacturing technology of optical communication cables and optical fiber is well known and described, for example, in the book Vernik SM, Gitin V.Ya., Ivanov BC Optical communication cables. - M.: Radio and Communications, 1988 .-- P.15-21, Fig. 3.

Channel photodetectors 9 ₁ -9 _m are designed for optoelectronic conversion of the received radiation of the corresponding channel and its preliminary amplification in the frequency bands of all m possible microwave subcarriers. The schemes of channel photodetectors 9 ₁ -9 _m are well known and can be implemented, as indicated in the book Moss T., Barrel G., Ellis B. Semiconductor optoelectronics: trans. from English M.: Mir, 1976. S.125-135.

Channel subcarrier determination devices 10 ₁ -10 _m are designed to isolate microwave subcarriers from the received signal. The principle of operation of the device for determining the subcarrier 10 _{m is} as follows: the signal from the output of the channel photodetector 9 _m is fed to the input of the channel device for determining the subcarrier 10 _m , amplified and divided into n signals, each of which is supplied to its own mixer (total n), to which one of m microwave subcarriers produced by the 3 _PFP synthesizer. At the output of the mixers, low-pass filters (low-pass filters) are installed, so that a nominal signal at the output of the low-pass filters will be formed only when the same subcarriers approach the mixer. This signal will determine the subcarrier received in this channel. At the boundaries of the clock intervals, the sync signal resets the previous value. Schemes of channel devices for determining the subcarrier are known and can be implemented as indicated in the book Kalashnikov N.I., Krupitsky E.I., Dorodnov I.L., Nosov V.I. Radio communication systems: textbook for universities. M .: Radio and communications, 1988. S.144-151.

The clock synchronization device 11 restores the clock frequency FT from its harmonics contained in the photocurrents of the channel photodetectors 9 ₁ -9 _m , and generates the signals necessary for clock synchronization of all functional nodes of the receiving terminal. The clock device circuitry is known and can be implemented, as indicated in the book by N. N. Slepov Modern technologies of digital fiber-optic communication networks. - M .: Eco-Trends, 2000 .-- 254-257 s.

The optical spectrum analyzer 12 measures the parameters of the received optical signal, namely, the value of the optical signal-to-noise ratio in each spectral channel. If the value of the ratio of the optical signal to noise in some spectral channel becomes lower than the required one, the optical spectrum analyzer sends a signal via the reverse communication channel to the control circuit of the channel optical transmitters 4, which provides the redistribution of the information flow from the faulty spectral channel and accordingly corrects the power, introduced into other spectral channels. An optical spectrum analyzer is a known device and can be implemented, as indicated in the book by Ivanov AB Fiber optics: components, transmission systems, measurements. - M .: Cyrus System Company, 1999. - S.337-338.

The decoder 13 provides decoding of the clock set of microwave subcarriers into the clock distribution of N binary symbols at the outputs of the decoder, repeating the distribution of symbols at the input of the encoder switch 3. The decoder circuit is known and can be implemented, for example, see the book Shilo V.L. Popular digital circuits. - M .: Radio and communications, 1987. - S.191-193, Fig.1.19.

The decoder of the switching signals 14 decrypts the service clock set with the formation of the corresponding control signal. The signal decoder circuit is known and can be implemented as indicated, for example, in the book of N. N. Slepov Modern technologies of digital fiber-optic communication networks. - M .: Eco-Trends, 2000. - S.145-147.

The controller of the switch digital channels 15 generates the appropriate command combination for the required switching transmitted to the switch. The controller of the digital channel switch is a known device and can be implemented, as indicated in the book by A. Shmalko. Digital communication networks: the basics of planning and construction. - M.: Eco-Trends, 2001 .-- P.64-66.

The digital channel switch 16 implements the switching of information flows for the respective users. The digital channel switch is a known device and can be implemented as indicated in the book by A. Shmalko. Digital communication networks: the basics of planning and construction. - M.: Eco-Trends, 2001 .-- S.114-116.

The output device from the terminal N synchronous information streams and clock frequency 17 is designed to output digital synchronous information streams, clock signals and switching signals and distributing them to subscribers and can be built according to any known scheme, for example, see the book Andreev I.A. , Burdin V.A. and others. Construction and technical operation of fiber-optic communication lines. Textbook for high schools. / Ed. B.V. Popova. - M .: Radio and communications, 1995. - S.93-97.

гармоник тактовой частоты, кратность и число которых определяются полосой рабочих частот оптоэлектронных узлов передающего и приемного терминалов (канальные оптические передатчики 6_m, канальные фотоприемные устройства 9_m), а также исходными техническими параметрами (число передаваемых цифровых информационных потоков N, число спектрально мультиплексируемых оптических каналов m). Эти n гармоник, предназначенные для использования далее в качестве СВЧ поднесущих передаваемых сигналов, подводятся на СВЧ входы кодера-коммутатора 3, а на другие входы кодера-коммутатора подводятся параллельно N входных цифровых информационных потоков, а также тактовая частота F_T и сигналы коммутации. Тактовый набор m СВЧ поднесущих подается одновременно на m канальных оптических передатчиков 6_m и схему управления канальными оптическими передатчиками 5, которая управляет значением мощности вводимого в оптическое волокно оптического сигнала. На другой вход схемы управления канальными оптическими передатчиками поступает сигнал от схемы управления коммутацией и в случае перераспределения нагрузки из неисправного спектрального канала по другим спектральным каналам схема управления оптическими передатчиками обеспечивает требуемое увеличение излучаемой мощности оптического сигнала. Передатчики излучают сигналы, каждый на своей длине волны (λ₁, …, λ_m), модулированные этими СВЧ поднесущими в течение данного тактового интервала. В конце каждого тактового интервала сигналом тактовой синхронизации производится сброс установки диодных СВЧ ключей, коммутирующих поднесущие, затем новая тактовая комбинация на N входах кодера-коммутатора 3 отображается (кодируется) в новое, однозначно соответствующее ей распределение r СВЧ поднесущих (из n возможных) и вся процедура повторяется такт за тактом. Выходные тракты оптических канальных передатчиков 6₁-6_m, подключаются к входам устройства объединения спектрально-разнесенных оптических каналов 7_ПЕР, обычно выполняемого в системах со спектральным мультиплексированием на основе оптических фильтров. Устройство 7_ПЕР суммирует m оптических сигналов с различными длинами волн (λ₁, …, λ_m), промодулированных на каждом такте "своим" распределением СВЧ поднесущих в групповой линейный оптический сигнал, который вводится в оптический тракт передачи линейного сигнала 8₁-8_M+1 (в линейное оптическое волокно).The device operates as follows. At the input of the transmitting terminal, N transmitted digital streams are supplied, which are fed to the terminal input device of the signals N synchronous information flows, clock frequency and switching signals 2. From the output of the switching control circuit 1, a switching signal is supplied to the corresponding input of the input device to the terminal of the N synchronous information signals streams, clock frequency and switching signals 2. The clock signal is fed to the input of the microwave synthesizer subcarriers 4 _PER , which generates n, where

harmonics of the clock frequency, the frequency and number of which are determined by the operating frequency band of the optoelectronic nodes of the transmitting and receiving terminals (channel optical transmitters 6 _m , channel photodetectors 9 _m ), as well as the original technical parameters (number of transmitted digital information streams N, number of spectrally multiplexed optical channels m). These n harmonics, intended for further use as microwave subcarriers of the transmitted signals, are fed to the microwave inputs of the encoder switch 3, and to the other inputs of the encoder switch are parallel N input digital information streams, as well as the clock frequency F _T and switching signals. The clock set of m microwave subcarriers is fed simultaneously to m channel optical transmitters 6 _m and a channel optical transmitter control circuit 5, which controls the power value of the optical signal input into the optical fiber. A signal from the switching control circuit is received at the other input of the channel optical transmitter control circuit, and if the load is redistributed from the faulty spectral channel to other spectral channels, the optical transmitter control circuit provides the required increase in the radiated power of the optical signal. The transmitters emit signals, each at its own wavelength (λ ₁ , ..., λ _m ), modulated by these microwave subcarriers during a given clock interval. At the end of each clock interval, the clock synchronization signal resets the installation of the diode microwave keys switching the subcarriers, then the new clock combination at the N inputs of the encoder switch 3 is mapped (encoded) into a new distribution of r microwave subcarriers (from n possible) that is uniquely corresponding to it and the whole the procedure is repeated step by step. The output paths of optical channel transmitters 6 ₁ -6 _m are connected to the inputs of a device for combining spectrally-separated optical channels 7 _PER , usually performed in systems with spectral multiplexing based on optical filters. The _PER device 7 summarizes m optical signals with different wavelengths (λ ₁ , ..., λ _m ) modulated at each clock cycle with "their own" distribution of microwave subcarriers into a group linear optical signal, which is introduced into the optical transmission path of the linear signal 8 ₁ -8 _{M +1} (in linear optical fiber).

At the input of the receiving terminal, after passing through the linear path, the group linear signal is first subjected, using the same _PFP device 7, but turned on in the opposite direction, to be divided into m spectrally separated optical channels, each of which is connected to the input of its own channel photodetector device 9 ₁ -9 _m , the output signals of which are fed to the inputs of the clock synchronization device 11, as well as to the inputs of the channel devices for determining the subcarrier 10 ₁ -10 _m and the optical spectrum analyzer 12, respectively. The optical spectrum analyzer 12 provides a measure of the optical signal-to-noise ratio in each spectral channel. If the value of the optical signal-to-noise ratio in each spectral channel corresponds to the norm, then the system continues to function in normal mode. If the value of the optical signal-to-noise ratio in some spectral channel deviates from the norm, then the output of the optical spectrum analyzer 12 through the feedback channel, which is organized in the flow in the opposite direction, receives the corresponding signal to the switching control circuit 1.

The recovered clock frequency F _T from the output of the clock synchronization device 11 is fed to the input of the synthesizer of the microwave subcarriers 4 of the _PFR similarly to the synthesizer in the transmitting terminal, with the only difference being that the set of m synthesized microwave subcarriers from the outputs of the synthesizer goes to more than one device (encoder switch 3) and the microwave inputs of all m channel devices for determining the subcarrier 10 ₁ -10 _m , in which this set is used to heterodyne the signals supplied from the outputs of the channel photodetectors 9 ₁ -9 _m .

Thus, the m channel set of microwave subcarriers from the outputs of the devices 10 ₁ -10 _{m is} supplied to the information inputs of the decoder 13 as the equivalent of the received clock set of microwave subcarriers and is displayed by the decoder 13 into the clock distribution of N binary symbols at the outputs of the decoder, repeating the distribution of symbols at the input of the encoder switch 3.

, где

- число размещений из r элементов по R.When the switching signal of the transmitted digital information flows is fed to the switching input of the encoder-switch 3, the encoder generates a “service” clock set of microwave subcarriers corresponding to this signal, which is not included in the encoding table of binary binary information sets, but is contained in the service signal coding table. If the number of switching (service) signals provided during the operation of the communication system is K, then the number r of subcarriers is taken so that

where

is the number of placements of r elements in R.

The passage of a service clock set along the optical path of the device does not differ from the passage of an information clock set, but in decoder 13, a service clock set that is not included in the decoding table of information clock sets is output to the input of the decoder of the switching signals 14, then it is transmitted to the input of the controller of the switch of digital information streams 15, in which, in turn, an appropriate command combination for the required switching is generated, which is transmitted to the switch 16. After completing In the case of switching, the order of arrangement of synchronous channels that existed at the input of the transmitting terminal and transferred to the output of decoder 13 will change to another one specified by the switching signal SK and implemented by switch 16. In this new order, the set of digital information streams through the output device from the terminal N synchronous information streams and clock frequency 17 goes to the equipment of the receiving subscribers (figure 1).

Claims (2)

1. The method of controlling the transmission rate of information flows, which consists in the fact that the set of N input symbols of the N-channel signal of the digital synchronous transmission system generated during each clock interval is encoded by a clock set of m microwave subcarriers from among n microwave subcarriers generated by the synthesizer subcarriers, wherein m, n and N are related by

where

- the number of arrangements of n elements in m, modulate the radiation of m channel optical transmitters, differing in optical wavelengths, by a clock set of m microwave subcarriers with simultaneous input of information on the clock frequency of the digital synchronous transmission system into the optical signal, transmit signals of various digital channels to any of used working optical wavelengths in accordance with the distribution of working wavelengths controlled by the control unit switching the used optical wavelengths between transmitting and receiving by the terminals of communication systems, combine the spectrally-spaced output optical signals of all m channel optical transmitters into a group optical linear signal, transmit the group optical linear signal along a linear optical path, divide the group optical signal into m components in the receiving terminal according to the difference in optical wavelengths, each component of the optical signal is detected by the channel photodetector; it is determined which value of the microwave subcarrier was transmitted for each of the m optical channels at a given time interval with simultaneous allocation of the clock frequency of the digital synchronous transmission system, form the equivalent of the clock set of m microwave subcarriers, similar to that obtained by encoding the input set of N symbols at the transmitting terminal, decode the equivalent of the clock set of m microwave subcarriers with the formation of the set N binary symbols distributed over a given clock interval over the N output channels of the receiving terminal in the same way as at the input of the transmitting terminal, which means that a switching signal is formed in such a way that when a signal is received about the deterioration of the optical signal-to-noise ratio in one of the spectral channels, the information flow from this spectral channel is redistributed over the others, or if it is necessary to increase the speed in a specific spectral channel the corresponding control action, then the set of N input symbols of the N-channel signal of the digital transmission system, generated during each clock interval, encoded by a clock set of m microwave subcarriers from among n microwave subcarriers, in accordance with the obtained control action and a switching signal, the emissions of m channel optical transmitters differing in optical wavelengths are modulated, by a clock set of m microwave subcarriers with simultaneous input of information into the optical signal about the clock frequency of the digital transmission system and switching signals, transmit signals of various digital channels at the used working optical wavelengths in accordance with the distribution of work their wavelengths by the control unit for switching the used optical wavelengths between the transmitting and receiving terminals of communication systems, in the receiving terminal, determine what value of the microwave subcarrier was transmitted for each of the m optical channels in a given clock interval with simultaneous allocation of the clock frequency of the synchronous transmission system and switching signals, they control the value of the optical signal-to-noise ratio and, in the event of a deviation from the norm in any spectral channel, transmit the corresponding the second signal on the reverse communication channel to form the switching signal, and after generating the equivalent of the clock set of m microwave subcarriers, decode the equivalent of the clock set of m microwave subcarriers and switching signals with the formation of a set of N binary symbols distributed over the N output channels during this clock interval the receiving terminal is the same as at the input of the transmitting terminal. 2. The method according to claim 1, characterized in that they transmit signals of various digital channels with different input signal power into the optical fiber.

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