Browsing by Author "SHAO, SK"

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WDM CODING FOR HIGH-CAPACITY LIGHTWAVE SYSTEMS
(1994-01-01)
SHAO, SK
;
KAO, MS
;
電信工程研究所
;
電信研究中心
;
Institute of Communications Engineering
An interchannel parallel coding scheme in the wavelength domain-the WDM coding system-is proposed. The system differs from the usual serial coding systems and provides many advantages. First, data channels are completely unaltered in the coding process, rendering it very suitable for practical lightwave systems with standard bit rate. Second, parallel encoding/decoding systems are simpler than those of serial coding systems, being easier to be implemented in high-speed optical systems. Third, compared with serial coding, WDM coding is able to reduce heavily the number of encoding/decoding pairs. For example, a (15, 11) Hamming coded WDM system reduces the number from 12 x 11 = 132 to 1 at the line rate of STS-12. Fourth, the WDM coding system could offer infinite coding gain in dispersion-limited lightwave systems. Finally, WDM coding systems could correct single-channel burst error. The system performance was evaluated and the system limitation imposed by bit-skew among wavelength channels was analyzed. The results indicated that a 15-channel Hamming coded WDM system can reduce the uncoded BER from 10(-9) to 3 x 10(-17) and the distance limitation imposed by bit-skew is 250 km if a dispersion-shifted fiber is used and a channel span of 30 nm is assumed
WDM CODING SYSTEM WITH SINGLE PARITY-CHECK CHANNEL
(1994-10-01)
KAO, MS
;
SHAO, SK
;
CHEN, HY
;
電信工程研究所
;
電信研究中心
We propose a modified WDM coding system with a single parity-check channel to achieve an efficient and flexible WDM coding system. The system provides most of the advantages of the original WDM coding system with just one parity-check channel. The bit rate and the data sequences are unaffected by the coding processes, making it very attractive for practical lightwave systems with standard rates. Compared to serial coding systems, it is able to reduce the number of encoding/decoding pairs in an m-channel WDM transmission system operated at STS-N from m x N to one. We have evaluated the system performance and analyzed the performance of frame synchronization needed for the modified WDM coding system. An example shows that the WDM coding can reduce the error floor of a four-channel dispersion-limited WDM system from 10(-10) to 10(-19) with reliable frame synchronization.