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Transmission characteristic compensation device, transmission characteristic compensation method, and communication device

A technology of transmission characteristics and compensation device, applied in transmission systems, optical fiber transmission, line transmission components, etc., can solve the problems of residual distortion, incomplete compensation of residual, and inability to improve compensation accuracy, and achieve the effect of improving compensation accuracy.

Active Publication Date: 2021-07-09
NTT ELECTORNICS CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0016] In the existing transmission characteristic compensation device, there is a problem that the compensation accuracy cannot be improved and residual distortion that cannot be fully compensated remains

Method used

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  • Transmission characteristic compensation device, transmission characteristic compensation method, and communication device
  • Transmission characteristic compensation device, transmission characteristic compensation method, and communication device
  • Transmission characteristic compensation device, transmission characteristic compensation method, and communication device

Examples

Experimental program
Comparison scheme
Effect test

Embodiment approach 1

[0033] figure 1 It is a diagram showing the communication device according to Embodiment 1 of the present invention. The communication device is a digital coherent optical receiver that receives an optical signal transmitted from a transmission side.

[0034] The polarization separation unit 1 separates an optical signal into X-polarized waves and Y-polarized waves. The photoelectric conversion section 2 converts a set of optical signals into analog electrical signals. The AD (Analog to Digital: analog-to-digital) conversion unit 3 converts a set of analog electrical signals into a set of digital electrical signals by sampling them at a predetermined sampling frequency. The digital signal processing section 4 restores (demodulates) transmission data by performing digital signal processing on the reception signal output from the AD conversion section 3 as a digital electric signal. The digital signal processing unit 4 has a transmission characteristic compensation device des...

Embodiment 1

[0045] Figure 4 It is a diagram showing Example 1 of the adaptive compensation coefficient calculation unit according to Embodiment 1 of the present invention. figure 2 The first adaptive compensator 7 of the shown receiving circuit 5 inputs the received X-polarized wave and Y-polarized wave, applies FIR filters to the X-polarized wave and Y-polarized wave respectively, and adds up the calculation results to obtain X-polarized wave and Y-polarized wave. output of polarized waves. Y-polarized wave output can also be obtained in the same manner. Therefore, the FIR filter of the first adaptive compensation unit 7 has a 2×2 butterfly filter structure.

[0046] The second adaptive compensation unit 10 of the adaptive compensation coefficient calculation unit 6 has a butterfly filter having the same configuration as the first adaptive compensation unit 7 described above. Next, the operation of the first embodiment for obtaining the optimum tap coefficients of the first and seco...

Embodiment 2

[0057] Figure 5 It is a diagram showing Example 2 of the adaptive compensation coefficient calculation unit according to Embodiment 1 of the present invention. In addition to the configuration of the adaptive compensation coefficient calculation unit 6 of the first embodiment, the frequency offset compensation unit 17 is connected to the preceding stage of the phase fluctuation compensating unit 14 , and the phase fluctuation compensating unit 18 is connected to the subsequent stage.

[0058] The phase fluctuation compensator 14 estimates the amount of phase fluctuation by comparing SP with its actual value. However, when the amount of phase fluctuation exceeds a certain amount of frequency offset, it cannot be accurately estimated. Therefore, a frequency offset compensation unit 17 for compensating the relatively large frequency offset output by the second adaptive compensation unit 10 is inserted in the preceding stage of the phase fluctuation compensation unit 14 . There...

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Abstract

The receiving circuit (5) has a first adaptive compensating unit (7) for compensating distortion of a received signal. The adaptive compensation coefficient calculation part (6) has: a known signal detection part (8), which detects the first known signal and the second known signal from the received signal; the second adaptive compensation part (10), which compensates the received signal Distortion of the signal; a tap coefficient initial value calculation unit (12), which calculates the initial value of the tap coefficient of the second adaptive compensation unit (10) by comparing the first known signal with its actual value; the first phase variation compensation unit (14) which uses the 2nd known signal to compensate the phase fluctuation of the output of the 2nd adaptive compensator (10); Comparing at least one of the first known signal and the second known signal after compensation by the first phase variation compensator (14) with its actual value, calculates the first adaptive compensator and the second adaptive compensator (7, 10) The tap coefficient.

Description

technical field [0001] The present invention relates to a transmission characteristic compensation device, a transmission characteristic compensation method, and a communication device for compensating characteristics of a transmission path in data communication. Background technique [0002] In coherent optical communication, the distortion of the transmission signal is compensated by digital signal processing, thereby achieving large-capacity transmission of tens of Gbit / s or more. In digital signal processing, processes such as dispersion compensation, polarization demultiplexing, polarization dispersion compensation, and frequency / phase variation compensation are performed. In order to realize a larger capacity, it is required to further improve the compensation accuracy of these processes. [0003] Adaptive equalization is also the most important function in digital signal processing. It mainly compensates for time-varying conditions such as polarization demultiplexing...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04B10/2507H04B3/10H04B10/61H04L27/01
CPCH04B10/616H04B10/614H04L27/38H04L27/22H04B3/10H04L27/01H04B10/61H04B10/2507H04B10/612H04B10/6162
Inventor 高椋智大山崎悦史大山胜一大沼靖治武井和人中村政则吉田光辉富泽将人木坂由明
Owner NTT ELECTORNICS CORP