WO2002089365A1 - Appareil de reception - Google Patents
Appareil de reception Download PDFInfo
- Publication number
- WO2002089365A1 WO2002089365A1 PCT/JP2002/004078 JP0204078W WO02089365A1 WO 2002089365 A1 WO2002089365 A1 WO 2002089365A1 JP 0204078 W JP0204078 W JP 0204078W WO 02089365 A1 WO02089365 A1 WO 02089365A1
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- WIPO (PCT)
- Prior art keywords
- signal
- reception signal
- optical
- reliability information
- identification
- Prior art date
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Classifications
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B10/00—Transmission systems employing electromagnetic waves other than radio-waves, e.g. infrared, visible or ultraviolet light, or employing corpuscular radiation, e.g. quantum communication
- H04B10/60—Receivers
- H04B10/66—Non-coherent receivers, e.g. using direct detection
- H04B10/69—Electrical arrangements in the receiver
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
- H03M13/00—Coding, decoding or code conversion, for error detection or error correction; Coding theory basic assumptions; Coding bounds; Error probability evaluation methods; Channel models; Simulation or testing of codes
- H03M13/37—Decoding methods or techniques, not specific to the particular type of coding provided for in groups H03M13/03 - H03M13/35
- H03M13/45—Soft decoding, i.e. using symbol reliability information
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/004—Arrangements for detecting or preventing errors in the information received by using forward error control
- H04L1/0045—Arrangements at the receiver end
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L1/00—Arrangements for detecting or preventing errors in the information received
- H04L1/20—Arrangements for detecting or preventing errors in the information received using signal quality detector
- H04L1/206—Arrangements for detecting or preventing errors in the information received using signal quality detector for modulated signals
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/02—Details ; arrangements for supplying electrical power along data transmission lines
- H04L25/06—Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection
- H04L25/061—Dc level restoring means; Bias distortion correction ; Decision circuits providing symbol by symbol detection providing hard decisions only; arrangements for tracking or suppressing unwanted low frequency components, e.g. removal of dc offset
- H04L25/062—Setting decision thresholds using feedforward techniques only
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L25/00—Baseband systems
- H04L25/38—Synchronous or start-stop systems, e.g. for Baudot code
- H04L25/40—Transmitting circuits; Receiving circuits
- H04L25/49—Transmitting circuits; Receiving circuits using code conversion at the transmitter; using predistortion; using insertion of idle bits for obtaining a desired frequency spectrum; using three or more amplitude levels ; Baseband coding techniques specific to data transmission systems
Definitions
- the present invention relates to a receiving device in a long-distance, high-speed optical transmission system, and more particularly to a receiving device capable of compensating for signal quality degradation after optical transmission and providing a high-quality transmission service.
- FIG. 11 is a block diagram showing a schematic configuration of the optical transmission system.
- the transmission device 100 includes an error correction coding circuit 101, a parallel-serial conversion circuit 102, and an electro-optic conversion unit 103.
- the receiving apparatus 200 includes an opto-electric conversion unit 111, an identification unit 112, a serial / parallel conversion circuit 113, and an error correction decoding circuit 115.
- the parallel transmission signal input to the transmitting apparatus 100 is subjected to error correction coding using, for example, a Reed-Solomon code in an error correction coding circuit 101, and then to a parallel-serial conversion circuit 102. Is output.
- the parallel-to-serial conversion circuit 102 converts the transmission signal subjected to the error correction code into a high-speed multiplexed signal, and outputs the multiplexed signal to the electro-optical converter 103.
- the electro-optical converter 103 converts an electric signal into an optical signal and outputs the signal on the transmission line 300.
- the receiving apparatus 200 receives the optical reception signal input via the transmission path 300, converts it into an electric reception signal, and outputs it to the identification unit 112.
- the identification unit 1 1 2 determines the mark / space by using one identification level L, and converts the converted power.
- the received signal is identified.
- the serial / parallel conversion circuit 113 converts the identified received signal into a parallel signal, and outputs the parallel signal to the error correction decoding circuit 115.
- Error correction decoding circuit 115 corrects a bit error caused by signal quality deterioration in transmission path 300, and outputs the error-corrected signal as a parallel reception signal.
- FIG. 12 is an explanatory diagram for explaining the relationship between the waveform of the electric reception signal input to the identification unit 112 and the identification level L.
- the quality of the optical reception signal input via the transmission line 300 is small, and in a good reception state, the waveform of the electric reception signal is good as shown in FIG. 12 (a).
- the poor reception condition where the quality of the optical reception signal is large and the eye opening of the electric reception signal waveform is small as shown in Fig. 9 (b) the deterioration on the mark side is particularly remarkable. . Therefore, in identification section 112, identification level L for determining a mark space is set in advance so that the best bit error rate can be obtained in a poor reception state.
- the receiving device 200 in the conventional optical transmission system described above determines the mark / space binary value based on one discrimination level L, and thus increases the transmission speed in order to improve the error correction performance. Improvement measures such as increasing the ratio of redundant bits to information bits of the error correction code have been taken.
- the conventional receiver described above since there is a trade-off relationship between the rate of increase in the transmission rate and the amount of deterioration in optical transmission quality, the conventional receiver described above has a problem in that it is difficult to improve the transmission quality and has limitations. there were.
- an object of the present invention is to provide a receiving apparatus in an optical transmission system capable of compensating for quality deterioration of an optical transmission signal and providing a high-quality transmission service without increasing the transmission speed.
- the receiving apparatus includes: a photoelectric conversion unit configured to convert an optical reception signal input via a transmission line into a first electrical reception signal and a second electrical reception signal; Multi-level identification means for identifying a received signal at a plurality of identification levels and generating a multi-valued identification signal corresponding to the identification result; and a reliability indicating the quality of the optical reception signal based on the second electrical reception signal.
- Optical reception quality determination means for generating degree information, and error correction decoding means for performing error correction with the multi-level identification signal with reference to the reliability information and outputting the error-corrected reception signal. It is characterized by having.
- the photoelectric conversion means converts the optical reception signal input via the transmission line into the first electrical reception signal and the second electrical reception signal
- the multi-level identification means converts the first electrical reception signal
- the signal is identified at a plurality of identification levels, a multi-valued identification signal corresponding to the identification result is generated, and the optical reception quality determination means indicates the quality of the optical reception signal based on the second electrical reception signal.
- Error information is generated, and error correction decoding means performs error correction using the multi-valued identification signal with reference to the reliability information, and outputs the error-corrected received signal.
- a receiving device is a photoelectric conversion device that converts an optical reception signal input via a transmission line into a first electric reception signal and a second electric reception signal, and the first electric reception signal.
- Optical reception quality determining means for generating reliability information indicating the quality of the optical reception signal; and identifying the second electrical reception signal at a plurality of identification levels based on the reliability information.
- a plurality of identification levels are variably operated based on the reliability information, and the second electric reception signal is identified based on the plurality of variably operated identification levels, and a multi-valued signal corresponding to the identification result is obtained.
- the multi-level identification means for generating an identification signal, and error correction decoding means for performing error correction using the multi-valued identification signal and outputting the error-corrected received signal.
- the multi-level identification means indicates the plurality of identification levels by the reliability information.
- the variable operation is performed according to the optical reception quality to identify the second electric reception signal.
- the error correction decoding means performs error correction using a multi-valued identification signal weighted according to the optical reception quality input from the multi-level identification means.
- the receiving apparatus converts the optical reception signal input via the transmission line into two minutes.
- a first optical splitter that branches, a first photodiode that converts one of the split lights of the first optical splitter into an electric reception signal, and a clock extraction that extracts a clock from an output signal of the first photodiode.
- a multilevel discriminator for discriminating an output signal of the first photodiode by a plurality of discrimination levels at a timing of the clock, and outputting a multi-level serial reception signal corresponding to the discrimination result;
- a serial-to-parallel conversion circuit for converting the multi-level serial reception signal into a multi-level parallel reception signal;
- a second splitter for extracting a predetermined wavelength component from the other split light of the first optical splitter;
- a second photodiode that converts output light of the two-branch device into an electric reception signal, an AZD converter that converts an output signal of the second photodiode into a digital signal, and the AZD converter based on the digital signal.
- An optical reception quality calculation circuit that generates reliability information indicating the quality of the optical reception signal; and an error correction using the multi-level identification signal with reference to the reliability information, and outputs the error-corrected reception signal.
- An error correction decoding circuit is provided.
- the optical reception signal input via the transmission path is branched into two.
- the multilevel discriminator discriminates the electrical reception signal obtained by electrically converting one of the split lights using a plurality of discrimination levels at the timing of the extracted extracted signal.
- the multi-valued parallel received signal as a result of this identification is given to the error correction decoding circuit.
- the electrical reception signal obtained by electrically converting the predetermined wavelength component optical signal extracted from the other branch light is converted into a digital signal for determining the quality of the optical reception signal by the AZD conversion.
- reliability information indicating the quality of the optical reception signal is generated from the digital signal, and is provided to the error correction decoding circuit.
- the error correction decoding circuit performs error correction based on the multi-level parallel received signal according to the optical reception quality indicated by the reliability information.
- a receiving device is a first optical splitter that splits an optical reception signal input via a transmission line into two, and extracts a predetermined wavelength component from one of the split lights of the first optical splitter.
- a second splitter a first photodiode that converts output light of the second splitter into an electric reception signal; an AZD converter that converts an output signal of the first photodiode into a digital signal; Based on the quality of the optical received signal
- An optical reception quality calculation circuit for generating reliability information indicating the identification information; an identification value control circuit for generating an identification level control signal for variably operating identification values of a plurality of identification levels in accordance with the reliability information;
- a second photodiode for converting the other split light of the one optical splitter into an electric reception signal, a clock extraction circuit for extracting a clock from the output signal of the second photodiode, and a plurality of A multi-level discriminator for discriminating an output signal of the second photodiode according to a discrimination level and outputting a multi-level serial reception signal corresponding to the discrimination result; and a multi-level parallel reception signal for the multi-level serial reception signal.
- the optical reception signal input via the transmission path is branched into two.
- a predetermined wavelength component light signal extracted from one of the split lights is converted into a digital signal for judging the quality of the light reception signal by an electric reception signal A_ / D converter obtained by electric conversion.
- reliability information indicating the quality of the optical reception signal is generated from the digital signal.
- a discrimination level control signal based on this reliability information is provided to the multi-level discriminator.
- the multi-level discriminator determines a plurality of discrimination levels in accordance with the discrimination level control signal at the timing of the clock extracted from the electric reception signal obtained by electrically converting the other branch light, that is, the optical reception indicated by the reliability information.
- the identified multi-level serial reception signal is converted into a parallel reception signal, supplied to an error correction decoding circuit, and error correction is performed according to the optical reception quality.
- a receiving device includes: a photodiode that converts an optical reception signal input via a transmission line into an electric reception signal; a clock extraction circuit that extracts a clock from the electric reception signal; and a timing of the clock.
- a multi-level discriminator that discriminates the electrical reception signal based on a plurality of discrimination levels and outputs a multi-level serial reception signal; and converts the multi-level serial reception signal into a multi-level parallel reception signal.
- a serial-to-parallel conversion circuit for converting the electric reception signal into a digital signal;
- An optical reception quality calculation circuit for generating reliability information indicating the quality of the optical reception signal based on the digital signal; and referring to the reliability information, performing error correction using the multi-valued identification signal.
- an error correction decoding circuit for outputting the error-corrected received signal.
- the multilevel discriminator discriminates an electric reception signal based on a plurality of discrimination levels at a clock timing extracted from an electric reception signal obtained by electrically converting an optical reception signal input via a transmission line. I do.
- the identified multi-level serial reception signal is converted into a parallel reception signal, which is provided to an error correction decoding circuit.
- the electrical reception signal obtained by electrically converting the optical reception signal input via the transmission path is converted into a digital signal for determining the quality of the optical reception signal by an A / D converter.
- reliability information indicating the quality of the optical reception signal is generated from the digital signal, and supplied to the error correction decoding circuit.
- the error correction decoding circuit performs error correction based on the multi-level parallel received signal according to the optical reception quality indicated by the reliability information.
- a receiving device includes: a photodiode for converting an optical reception signal input via a transmission line into an electric reception signal; an A / D converter for converting the electric reception signal into a digital signal; An optical reception quality calculation circuit that generates reliability information indicating the quality of the optical reception signal based on the signal; and an identification level control signal that variably operates identification values of a plurality of identification levels in accordance with the reliability information.
- An identification value control circuit for generating a clock, a clock extraction circuit for extracting a clock from the electrical reception signal, and a timing of the clock, wherein when identifying the electrical reception signal by a plurality of identification levels, A multilevel discriminator that variably operates according to the discrimination level control signal and outputs a multilevel serial reception signal; and a multilevel parallel reception signal that converts the multilevel serial reception signal to a multilevel serial reception signal.
- the electrical reception signal obtained by electrically converting the optical reception signal input via the transmission path is used as a digital signal for determining the quality of the optical reception signal by the A / D converter. Is converted to a number.
- reliability information indicating the quality of the optical reception signal is generated from the digital signal.
- a discrimination level control signal based on this reliability information is provided to the multi-level discriminator.
- the multi-level discriminator variably operates a plurality of discrimination levels according to the discrimination level control signal, that is, according to the optical reception quality indicated by the reliability information, at the timing of the clock extracted from the electric reception signal. Identify the signal.
- the identified multi-level serial reception signal is converted into a parallel reception signal, and is supplied to an error correction decoding circuit, where error correction according to the optical reception quality is performed.
- the reliability information is information of any one of optical reception power, optical SN ratio, optical reception wavelength, or information obtained by arbitrarily combining these.
- the reliability information any one of optical reception power, optical SN ratio, and optical reception wavelength, or information obtained by arbitrarily combining these is used.
- the receiving apparatus according to the next invention is characterized in that, in the above invention, the reliability information is generated in synchronization with the above-mentioned cache identification timing.
- the reliability information is generated in synchronization with the clock identification timing.
- the receiving apparatus is characterized in that, in the above invention, the reliability information is applied to an error correction code that treats n (n is a natural number) bits as one symbol, and is generated for each symbol.
- the reliability information is applied to an error correction code that treats n (n is a natural number) bits as one symbol, and is generated for each symbol.
- FIG. 1 is a block diagram showing a schematic configuration of a receiving apparatus according to Embodiment 1 of the present invention.
- FIG. 2 is a block diagram showing a detailed configuration of the receiving apparatus shown in FIG. Fig. 3 shows the waveform and identification of the electrical reception signal input to the multi-level identifier.
- FIG. 4 is an explanatory diagram for explaining a relationship between the identification signal and the reliability information.
- FIG. 4 is a timing chart showing a relationship between the identification signal and the reliability information.
- FIG. 5 is a timing chart showing the relationship between the identification signal and the reliability information.
- FIG. 6 is a block diagram showing a schematic configuration of a receiving apparatus according to Embodiment 2 of the present invention.
- FIG. 7 is a timing chart showing another example of the receiving apparatus shown in FIG. FIG.
- FIG. 8 is a block diagram showing a detailed configuration of the device.
- FIG. 8 is an explanatory diagram for explaining the relationship between the waveform of an electric reception signal input to a multi-level discriminator and the discrimination level
- FIG. 10 is a block diagram illustrating a configuration of a receiving apparatus according to Embodiment 3 of the present invention.
- FIG. 10 is a block diagram illustrating a configuration of a receiving apparatus according to Embodiment 4 of the present invention. Shows the general configuration of an optical transmission system including a conventional receiver.
- a proc view, first FIG. 2 is an explanatory view illustrating a relationship between the waveform and the discrimination level of the electrical received signal input into the unit shown in the first 1 FIG. BEST MODE FOR CARRYING OUT THE INVENTION
- FIG. 1 is a block diagram showing a schematic configuration of a receiving apparatus according to Embodiment 1 of the present invention.
- the receiving device 100 corresponds to the receiving device 200 shown in FIG. 11, and the receiving device 100 receives an optical reception signal via the transmitting device 100 and the transmission path 300. Is done.
- a receiving apparatus 10 includes an opto-electric conversion unit 11, a multi-level identification unit 12, a serial / parallel conversion circuit 13, an optical reception quality determination unit 14, and an error correction decoding circuit 15. Have.
- the opto-electric conversion unit 11 converts an optical reception signal input via the transmission path 300 into an electric signal of a first electric reception signal and a second electric reception signal.
- the first electric reception signal is output to the multi-level identification unit 12, and the second electric reception signal is output to the optical reception quality determination unit 14.
- the multi-level discriminating unit 12 performs a plurality of discriminations on the input first electric receiving signal.
- the signals are identified at different levels LI to L3 and output to the serial / parallel conversion circuit 13 as multivalued identification signals.
- the serial-to-parallel conversion circuit 13 performs serial-to-parallel conversion on the input multi-valued identification signal, and outputs the result to the error correction decoding circuit 15 as a multi-valued parallel signal.
- the optical reception quality determination unit 14 generates reliability information indicating the quality of the optical reception signal based on the second electrical reception signal input from the photoelectric conversion unit 11, and this reliability information Is output to the error correction decoding circuit 15.
- the reliability information is generated as any one of the optical reception power, the optical SN ratio, and the optical reception wavelength, or information obtained by arbitrarily combining these.
- the error correction decoding circuit 15 corrects an error correction by a multi-level parallel signal, which is a signal obtained by the multi-level identification section 12 identifying the first electric reception signal based on a plurality of identification levels L 1 to L 3. This is performed by referring to the reliability information input from the reception quality determination unit 14, and the parallel reception signal after error correction decoding is output to a subsequent reception processing system (not shown). As a result, the error correction decoding circuit 15 can improve the error correction capability, and can perform error correction with a high probability even if the optical reception quality is degraded in the transmission path 300.
- FIG. 2 is a block diagram showing a detailed configuration of the receiving device 10 shown in FIG.
- the photoelectric conversion unit 11 includes an optical splitter 11a, a photodiode 11b, an optical demultiplexer 11c, and a photodiode 11d.
- the optical splitter 11a splits the optical reception signal input from the transmission line 300 into two at a predetermined ratio, outputs one split light to the photodiode 11b, and splits the other split light into light. Output to the filter 11c.
- the photodiode 11 b converts one of the optical reception signals split by the optical splitter 11 a into an electric reception signal, and outputs the electric reception signal to the multilevel identification unit 12 as a first electric reception signal.
- the optical demultiplexer 11c sweeps the wavelength of the other optical reception signal split by the optical splitter 11a, extracts a predetermined wavelength component, and outputs the wavelength component to the photodiode 11d.
- the photodiode 11 d converts the optical signal of a predetermined wavelength component extracted by the optical demultiplexer 11 c into an electric signal, and outputs the electric signal as a second electric reception signal. Output to
- the multi-level discriminator 12 includes a multi-level discriminator 12a and a clock extraction circuit 12b.
- the clock extraction circuit 12b extracts a clock component from the first electrical reception signal output from the photodiode 11b, and uses the extracted clock (hereinafter referred to as “reception extraction clock”) as a multi-level discriminator 12b. Output to a.
- the multi-level discriminator 12a uses a plurality of discrimination levels L1 to L3, and uses the plurality of discrimination levels L1 to L3 at the timing of the reception extraction clock to output the photodiodes 11b output from the photodiode 11b. 1. Identify the electrical reception signal and output the identified multi-level serial reception signal to the serial-to-parallel conversion circuit 13.
- the serial / parallel conversion circuit 13 converts the multi-valued serial reception signal into a multi-valued parallel signal at a low speed, and outputs it to the error correction decoding circuit 15.
- the optical reception quality determination unit 14 has an AZD converter 14a and an optical reception quality calculation circuit 14b.
- the / 0 converter 14 converts the second electric reception signal output from the photodiode 11 d into a digital signal, and outputs the digital signal to the optical reception quality calculation circuit 14 b.
- the optical reception quality calculation circuit 14b generates reliability information based on the digital signal output from the AZD converter 14a, and outputs the reliability information to the error correction coding circuit 15. I do.
- the optical reception quality calculation circuit 14b generates, as the reliability information, any one of the optical reception power, the optical SN ratio, and the optical reception wavelength, or any combination thereof. Then, the data is output to the error correction decoding circuit 15.
- the error correction coding circuit 15 converts the multi-level parallel signal input from the serial-to-parallel conversion circuit 13 based on the reliability information input from the optical reception quality calculation circuit 14 b based on the reliability information. Error correction is performed and output to a subsequent reception processing system (not shown) as a parallel reception signal.
- FIG. 4 is an explanatory diagram for explaining the waveform of the first electric reception signal input to the multi-level discriminator 12a and the relationship with the plurality of discrimination levels L1 to L3.
- FIG. 5 shows an identification signal identified by a plurality of identification levels L1 to L3.
- FIG. 6 is a diagram showing a relationship between the information and reliability information.
- the optical splitter 11a converts one of the optical reception signals branched into two at a predetermined branching ratio into a first electrical reception signal in a photodiode 11b, and a clock extraction circuit 1 2b and the multi-level discriminator 12a.
- the waveform of the first electrical reception signal input to the multi-level discriminator 12a has a good eye opening as shown in Fig. 3 (a) when the quality of the optical reception signal is good.
- the noise distribution between the mark side and the space side is also almost symmetric.
- the mark side is significantly deteriorated and the noise distribution becomes asymmetric, as shown in FIG. 3 (b).
- the multi-level discriminator 12a discriminates the first electric reception signal using the three discrimination levels L1 to L3 at the timing of the reception extraction clock output from the clock extraction circuit 12b.
- the discrimination level L2 is located at the level of the center position of the eye opening, and the discrimination levels L1 and L3 are disposed above and below the level. That is, the identification levels L1 to L3 are arranged at wide intervals in order to sufficiently identify the opening of the eye opening.
- the multi-level discriminator 1 2a discriminates the binary first electrical reception signal by three values based on these three discrimination levels L1 to L3, and outputs a quaternary signal (0, 1, 2, 3). ) To the serial / parallel conversion circuit 13.
- the quaternary signal is represented as “0 0”, “01”, “10”, and “11” in a 2-bit binary representation, respectively.
- a parallel quaternary signal is output to the error correction decoding circuit 15.
- the other of the optical reception signals branched into two at a predetermined branching ratio by the optical branching unit 11a is output to the optical demultiplexer 11c.
- the optical signal of a predetermined wavelength component extracted by the optical demultiplexer 11c is electrically converted by the photodiode 11d, output to the A "D converter 14a as a second electrical reception signal, and The signal is converted into a digital signal by the D converter 14a and output to the optical reception quality calculation circuit 14b.
- the optical reception quality calculation circuit 14b converts, for example, Signal power, optical signal-to-noise ratio, optical reception wavelength, or any combination of these are calculated and calculated, and the result of this calculation is used as reliability information indicating the quality of the optical reception signal.
- the signal is input to the decoding circuit 15.
- the error correction decoding circuit 15 corrects error bits in the received signal using the above-described parallel quaternary signal and the reliability information, and outputs it as a parallel received signal. If the quality of the optical reception signal deteriorates due to a decrease in the reception power of the optical reception signal, degradation of the optical SN ratio, or a shift in the wavelength of the optical signal, the waveform of the electrical reception signal changes as shown in Fig. 3 (b). Deterioration becomes significant and the noise distribution becomes asymmetric. In this case, since the three discrimination levels L 1 to L 3 are constant values, unlike the discrimination values shown in FIG. 3 (a) where the optical reception quality is good, each of the four discrimination levels is different. Weight changes.
- the error correction decoding circuit 15 performs error correction by referring to the reliability information, even if the optical reception quality is poor, that is, even if the bit error rate is high, each bit error Can be correctly detected and corrected.
- the error correction decoding circuit 15 performs error correction using the parallel multi-level signal expanded in parallel and the parallelized reliability information, so that large-scale integration and low power consumption can be achieved. It can be composed of a CMOS-LSI, and the size and power consumption of the receiving device 10 can be reduced.
- the A / D converter 14a and the optical reception quality calculation circuit 14b can have a simple configuration.
- the light may be branched before performing the wavelength-division demultiplexing.
- Embodiment 2 Next, a second embodiment of the present invention will be described.
- error correction of a quaternary signal is performed based on quaternary signals identified by a plurality of fixed identification levels L1 to L3 and reliability information.
- a plurality of identification levels L1 to L3 are changed based on the reliability information, and error correction is performed based on the quaternary signal obtained thereby.
- the second embodiment a plurality of identification levels L1 to L3 are changed based on the reliability information, and error correction is performed based on the quaternary signal obtained thereby.
- FIG. 6 is a block diagram showing a schematic configuration of a receiving apparatus according to Embodiment 2 of the present invention.
- the receiving apparatus 20 has a multi-level identifying section 22 in place of the multi-level identifying section 12 of the receiving apparatus 10 shown in FIG.
- the reliability information generated by the optical reception quality determination unit 24 having the same function is input to the multi-level identification unit 22.
- an error correction decoding circuit 25 is provided in place of the error correction decoding circuit 15.
- Other configurations are the same as those of the first embodiment, and the same components are denoted by the same reference numerals.
- the multi-level identification unit 22 identifies the first electric reception signal output from the photoelectric conversion unit 11 by a plurality of identification levels L1 to L3. At this time, a plurality of discrimination levels L1 to L3 are changed according to the reliability information input from the optical reception quality judgment unit 24, and the multi-level discrimination is performed by the plurality of changed discrimination levels. The unit 22 generates a multi-valued identification signal.
- the error correction decoding circuit 25 performs error correction based on a multi-level parallel signal that is a signal identified by a plurality of identification levels variably operated in accordance with the reliability information.
- the parallel reception signal after error correction decoding is output to a reception processing system (not shown) at the subsequent stage.
- FIG. 7 is a block diagram showing a detailed configuration of the receiving device shown in FIG.
- the optical reception quality determination section 24 has an AZD converter 24a and an optical reception quality calculation circuit 24b, and has the same configuration as the optical reception quality determination section 14 shown in FIG. It is. However, the optical reception quality calculation circuit 24b is different from the optical reception quality calculation circuit 14b.
- the generated reliability information is output to the multi-level identification unit 22 and not output to the error correction decoding circuit 25.
- the multi-level discriminator 22 includes a multi-level discriminator 22 a, a clock extraction circuit 22 b, and a discrimination value control circuit 22 c.
- the clock extraction circuit 22b has the same configuration as the clock extraction circuit 12b.
- the identification value control circuit 22c generates an identification level control signal for controlling the identification levels of the variable identification levels L1 to L3 based on the reliability information input from the optical reception quality operation circuit 24b. Generate and output to multi-level classifier 22a.
- the multi-level discriminator 22 a includes a plurality of discrimination levels LI ′ to L variably operated by the discrimination level control signal based on the timing of the reception extraction clock input from the clock extraction circuit 22 b. According to 3 and, the first electrical reception signal input from the photodiode 11 b is identified, and the identified serial 4-valued signal is output to the serial-parallel conversion circuit 13.
- the error correction coding circuit 25 corrects the error using the parallel quaternary signal output from the serial / parallel conversion circuit 13 and outputs it as a parallel reception signal to a subsequent reception processing system (not shown).
- the waveform of the first electric reception signal input to the multi-level discriminator 22a is good when the quality of the optical reception signal is good, as shown in FIG. 8 (a). It has a large eye opening, and the noise distribution on the mark side and the space side is almost symmetric. On the other hand, when the optical reception quality is degraded, as shown in Fig. 8 (b), the mark side is significantly degraded, and the noise distribution becomes asymmetric.
- the multi-level discriminator 22 a divides the first electric reception signal by three variable discrimination levels L 1 ′ to L 3 ′ based on the timing of the reception extraction clock from the clock extraction circuit 22 b.
- the identified four-level serial signal is output to the serial / parallel conversion circuit 13. At this time, it is variable according to the discrimination level control signal from the discrimination value control circuit 22c. Manipulate.
- the three discrimination levels L1 to L3 are such that the discrimination level L2 is located at the center of the eye opening, Is operated so that the identification levels L1 and L3 are arranged at wide intervals.
- the discrimination level L 2 which is at the center of the eye opening and is not different from the discrimination level L 2
- the narrowing of the eye opening degree it is operated so as to be arranged at a narrow interval near the center of the eye opening.
- the multi-level discriminator 22a generates a discrimination signal of a quaternary signal (0, 1, 2, 3) which is weighted according to the optical reception quality, and generates a serial-to-parallel conversion circuit 1 Output to 3.
- the error correction decoding circuit 25 corrects error bits in the received signal with the parallel quaternary signal output from the serial / parallel conversion circuit 13 and outputs the same as a parallel received signal.
- the electric reception signal waveform is marked as shown in Fig. 8 (b).
- the degradation on the side becomes remarkable, and the noise distribution becomes asymmetric.
- the identification level is appropriately controlled according to the optical reception quality, even if the optical reception quality is poor, that is, even if the bit error rate is high, each bit error is correctly detected and corrected. Will be able to
- the error correction decoding circuit 25 performs error correction using parallel multi-valued signals that have been developed in parallel, and therefore, as in the first embodiment, a CMO S ⁇ that can achieve large-scale integration and low power consumption. It can be composed of LSI, and it is possible to reduce the size and power consumption of the receiver.
- FIG. 9 is a block diagram showing a detailed configuration of a receiving apparatus according to Embodiment 3 of the present invention. It is.
- the photodiode 31 of the receiving device 30 is replaced by the photoelectric conversion unit 11 shown in the first embodiment. That is, the optical branching unit 11a, the optical demultiplexer 11c, and the photodiode 11d of the photoelectric conversion unit 11 shown in the first embodiment are deleted.
- the A / D converter 34 a of the optical reception quality determination section 34 has an electric reception signal from the photodiode 31. Is entered.
- Other configurations are the same as those of the first embodiment, and the same components are denoted by the same reference numerals.
- the third embodiment is not an electric signal of only the wavelength-selected signal component output from the photodiode 11 d as in the first embodiment, the photodiode 31 almost includes this signal component.
- the first embodiment it is possible to obtain reliability information for evaluating the optical reception quality.
- the same operation and effect as in the first embodiment can be obtained with a simple configuration.
- FIG. 10 is a block diagram showing a detailed configuration of a receiving apparatus according to Embodiment 4 of the present invention.
- the photodiode 41 of the receiving device 40 is replaced by the photoelectric conversion unit 11 shown in the second embodiment. That is, the configuration is such that the optical branching unit 11a, the optical splitter 11c, and the photodiode 11d of the photoelectric conversion unit 11 shown in the second embodiment are deleted. Note that, with the simplicity of this configuration, unlike the AZD ⁇ 24a, the A / D converter 44a of the optical reception quality judging unit 44, unlike the AZD ⁇ 24a, receives the electrical reception signal from the photodiode 41. Is entered. Other configurations are the same as those of the second embodiment, and the same components are denoted by the same reference numerals.
- the electric signal is not only the wavelength-selected signal component output from the photodiode 11 d, but the photodiode 41 almost contains this signal component. Therefore, as in the second embodiment, the optical reception quality was evaluated. It is possible to obtain the reliability information to be valued. As a result, in the fourth embodiment, the same operational effects as those of the second embodiment can be obtained with a simple configuration.
- the receiving apparatus can perform error correction based on the multi-valued identification signal according to the optical reception quality indicated by the reliability information, so that even if the optical reception quality is degraded, Error correction can be performed with high probability. Therefore, it becomes possible to realize a long-distance and high-speed optical transmission device that compensates for the quality degradation of the optical transmission signal and provides a high-quality transmission service.
- the receiving apparatus can perform error correction using the multi-valued identification signal weighted according to the optical reception quality, even if the optical reception quality is degraded, it can be performed with high probability. Error correction can be performed. Therefore, it is possible to realize a long-distance and high-speed optical transmission device that compensates for the deterioration of the optical transmission signal and provides a high-quality transmission service.
- the optical reception signal input via the transmission line is divided into two, and the electric reception signal obtained by electrically converting one of the divided lights is identified at a plurality of identification levels.
- a parallel received signal is generated.
- a predetermined wavelength component optical signal is extracted from the other split light, and reliability information indicating the quality of the optical reception signal is generated from the electric reception signal obtained by electrically converting the extracted signal. Therefore, error correction using multi-level parallel reception signals can be performed according to the optical reception quality indicated by the reliability information.
- Such an error correction decoding circuit can be composed of a CMO S-LSI capable of large-scale integration and low power consumption, and the downsizing and low power consumption of the receiving device can be achieved.
- the optical reception signal input through the transmission path is split into two, and the predetermined wavelength component optical signal extracted from one of the split lights is converted from the electrical reception signal into the optical reception signal. Is generated, and a discrimination level control signal based on the reliability information is provided to the multi-level discriminator.
- the multi-level discriminator variably operates a plurality of discrimination levels for discriminating the electric reception signal obtained by electrically converting the other branch light according to the optical reception quality indicated by the reliability information, and discriminates the electric reception signal.
- a multi-level parallel reception signal weighted according to the optical reception quality is generated, and error correction is performed. It is provided to the normal decoding circuit. Therefore, the error correction decoding circuit can perform error correction according to the optical reception quality.
- Such an error correction decoding circuit can be constituted by a CMO S-LSI that can be integrated on a large scale and reduced in power consumption, and the receiver can be reduced in size and power consumption.
- the electrical reception signal obtained by electrically converting the optical reception signal input via the transmission line is identified by a plurality of identification levels, and the identified multilevel serial reception signal is received in parallel.
- the signal is converted to a signal and supplied to an error correction decoding circuit.
- the electrical reception signal is converted into a digital signal for determining the quality of the optical reception signal, and reliability information indicating the quality of the optical reception signal is generated from the digital signal and supplied to an error correction decoding circuit.
- the error correction decoding circuit can perform the error correction using the multi-level parallel received signal according to the optical reception quality indicated by the reliability information.
- Such an error correction decoding circuit can be composed of a CMO S-LSI capable of large-scale integration and low power consumption, and the receiver can be small-sized and low power consumption.
- the electrical reception signal obtained by electrically converting the optical reception signal input via the transmission path is converted into a digital signal for determining the quality of the optical reception signal, and the optical reception signal is converted from the digital signal.
- Reliability information indicating the quality of the signal is generated.
- a discrimination level control signal based on this reliability information is provided to the multi-level discriminator.
- the multi-level discriminator variably operates a plurality of discrimination levels according to the discrimination level control signal, that is, according to the optical reception quality indicated by the reliability information, at the timing of the clock extracted from the electric reception signal. Identify.
- the identified multi-level serial reception signal is converted into a parallel reception signal, which is provided to an error correction decoding circuit.
- error correction can be performed using a parallel multilevel signal weighted according to the optical reception quality.
- Such an error correction decoding circuit can be composed of a CMO S-LSI capable of large-scale integration and low power consumption, and can reduce the size and power consumption of the receiver.
- any one of the optical reception power, the optical SN ratio, and the optical reception wavelength, or information obtained by arbitrarily combining these, can be used as the reliability information. it can.
- the reliability information is generated in synchronization with the identification timing of the clock, a high error correction capability can be provided.
- the reliability information is applied to an error correction code that treats n bits (n is a natural number) as one symbol, and is generated for each symbol.
- the processing system to be generated can be simplified. Industrial applicability
- the receiving apparatus according to the present invention is suitable for a long-distance and high-speed optical transmission system.
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- Engineering & Computer Science (AREA)
- Computer Networks & Wireless Communication (AREA)
- Signal Processing (AREA)
- Physics & Mathematics (AREA)
- Power Engineering (AREA)
- Theoretical Computer Science (AREA)
- Probability & Statistics with Applications (AREA)
- Quality & Reliability (AREA)
- Electromagnetism (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Optical Communication System (AREA)
- Dc Digital Transmission (AREA)
- Detection And Prevention Of Errors In Transmission (AREA)
Description
Claims
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US10/466,887 US20040062556A1 (en) | 2001-04-27 | 2002-04-24 | Reception apparatus |
EP02722744A EP1383254A4 (en) | 2001-04-27 | 2002-04-24 | RECEPTION DEVICE |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2001133489A JP2002330104A (ja) | 2001-04-27 | 2001-04-27 | 受信装置 |
JP2001-133489 | 2001-04-27 |
Publications (1)
Publication Number | Publication Date |
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WO2002089365A1 true WO2002089365A1 (fr) | 2002-11-07 |
Family
ID=18981340
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2002/004078 WO2002089365A1 (fr) | 2001-04-27 | 2002-04-24 | Appareil de reception |
Country Status (4)
Country | Link |
---|---|
US (1) | US20040062556A1 (ja) |
EP (1) | EP1383254A4 (ja) |
JP (1) | JP2002330104A (ja) |
WO (1) | WO2002089365A1 (ja) |
Cited By (1)
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US7239673B2 (en) | 2001-09-13 | 2007-07-03 | Mitsubishi Denki Kabashiki Kaisha | Optical reception apparatus |
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JP4654105B2 (ja) * | 2005-10-11 | 2011-03-16 | 富士通株式会社 | 光受信回路 |
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US8737197B2 (en) | 2010-02-26 | 2014-05-27 | Net Optic, Inc. | Sequential heartbeat packet arrangement and methods thereof |
US9306959B2 (en) | 2010-02-26 | 2016-04-05 | Ixia | Dual bypass module and methods thereof |
US9749261B2 (en) | 2010-02-28 | 2017-08-29 | Ixia | Arrangements and methods for minimizing delay in high-speed taps |
US8755293B2 (en) | 2010-02-28 | 2014-06-17 | Net Optics, Inc. | Time machine device and methods thereof |
US8902735B2 (en) | 2010-02-28 | 2014-12-02 | Net Optics, Inc. | Gigabits zero-delay tap and methods thereof |
US9937124B2 (en) | 2014-09-11 | 2018-04-10 | International Business Machines Corporation | Microchip substance delivery devices having low-power electromechanical release mechanisms |
US9755701B2 (en) * | 2015-03-31 | 2017-09-05 | International Business Machines Corporation | Hybrid tag for radio frequency identification system |
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US10881788B2 (en) | 2015-10-30 | 2021-01-05 | International Business Machines Corporation | Delivery device including reactive material for programmable discrete delivery of a substance |
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Also Published As
Publication number | Publication date |
---|---|
EP1383254A1 (en) | 2004-01-21 |
JP2002330104A (ja) | 2002-11-15 |
US20040062556A1 (en) | 2004-04-01 |
EP1383254A4 (en) | 2006-10-04 |
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