Multiplex communications – Diagnostic testing – Fault detection
Reexamination Certificate
1999-04-05
2003-12-02
Hsu, Alpus H. (Department: 2665)
Multiplex communications
Diagnostic testing
Fault detection
C370S543000, C370S535000, C341S059000, C341S094000, C359S199200, C714S752000, C714S776000
Reexamination Certificate
active
06657967
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a dummy bit elimination device for eliminating dummy bits added to an,FEC (Forward Error Correction) code which is transmitted on a submarine cable system.
2. Description of the Prior Art
In a submarine cable system, a processing device for generating FEC code, for example a Reed-Solomon code, based on an optical signal input adds the dummy bits to the FEC code to simplify the configuration thereof.
Adding the dummy bit according to a conventional method, however, increases a bit rate on the communication channel. A transmission loss is increased in accordance with the increased bit rate. Thus, for example, it was required to compensate the loss by increasing a number of repeaters.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a dummy bit elimination device for eliminating the dummy bit added to the FEC code that is transmitted on the submarine cable system.
According to a first aspect of the present invention, there is provided a dummy bit elimination device included in a coding apparatus, which device comprises: means for eliminating only dummy bits from FEC code supplied thereto so as to output only the FEC Code; wherein the coding apparatus comprises: a means for converting an optical signal into an electrical signal data; a demultiplexer for demultiplexing the data; a coding means for generating an FEC (Forward Error Correction) code having the demultiplexed data and additional parities, and dummy bits for each of the demultiplexed data; a multiplexer for multiplexing inputs thereto; and a means for converting an output of the multiplexer into an optical signal; and wherein the dummy bit elimination device and an output of the dummy bit elimination device are fed to the multiplexer.
According to a second aspect of the present invention, there is provided a coding apparatus, which apparatus comprises: a means for converting an optical signal into an electric signal data; a demultiplexer for demultiplexing the data; a coding means for generating an FEC code having the demultiplexed data and additional parities, and dummy bits for each of demultiplexed data; a dummy bit eliminating means for eliminating only the dummy bits from outputs of the coding means so as to output only the FEC codes; a multiplexer for multiplexing outputs of the dummy bit eliminating means; and a means for converting an output of the multiplexer into an optical signal.
The coding apparatus may be combined with a submarine cable system.
According to a third aspect of the present invention, there is provided a coding apparatus which comprises: a coding means for continuously outputting an FEC code word having an input data and additional parities, and dummy bits to simplify an FEC coding; and a dummy bit eliminating means for eliminating only the dummy bits from a continuity consisting of the FEC code and the dummy bits so as to output only the FEC code.
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Japanese Office Action, dated Aug. 30, 2000, with English language translation of Japanese Examiner's comments.
European Patent Office Communication in corresponding EPO case.
Fujisawa Takanori
Hara Yasushi
Nomura Kenichi
Tanaka Hiroaki
Yanagi Norio
Hsu Alpus H.
NEC Corporation
Whitham Curtis & Christofferson, PC
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