Guided scrambling: a new line coding technique for high bit rate fiber optic transmission systems

Fair, I.J.; Grover, W.D.; Krzymien, W.A.; MacDonald, R.I.

doi:10.1109/26.76466

Cited by 87 publications

(33 citation statements)

References 16 publications

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“…Quotient selection mechanisms that have been proposed in the literature for balanced encoding include 1. Select the quotient with the lowest magnitude of RDS at the end of the word [9]. 2.…”

Section: Quotient Selection For Balanced Encodingmentioning

confidence: 99%

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Generation of balanced quadrature phase shift keyed sequences through guided scrambling

Fair

2015

IET Communications

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Balanced codes (also called DC-free codes) are widely used in binary communication systems to increase the likelihood of accurate symbol recovery with practical demodulators. Guided scrambling (GS) is recognised as a viable approach to efficiently generate DC-free binary sequences. In this study the authors extend the use of GS to generate balanced sequences of quadrature phase shift keyed (QPSK) symbols by using arithmetic from the ring of polynomials defined over the Galois field of four elements. In addition to ensuring adequate timing information and consistent decision thresholds to improve the performance of practical demodulators, balanced encoding of QPSK symbol sequences creates a null at DC in the spectrum of the equivalent complex baseband signal. This corresponds to a null at the centre frequency of the bandpass QPSK signal that enables the insertion of a pilot tone and avoidance of narrowband interference without filtering or distortion of the signal. The authors outline sufficient conditions for the generation of balanced GS QPSK sequences, and based upon these conditions the authors recommend scrambling polynomials and quotient selection criteria. The authors then present analytical and simulation results that confirm the generation of balanced sequences using this approach.

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Section: Quotient Selection For Balanced Encodingmentioning

confidence: 99%

“…Let a i (x), i = 0,1 … B A − 1, be the ith pattern of A augmenting symbols. The ith quotient in the selection set is [9] …”

Section: Polynomials For Balanced Encodingmentioning

confidence: 99%

Generation of balanced quadrature phase shift keyed sequences through guided scrambling

Fair

2015

IET Communications

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“…To scramble an RS codeword, a data word of every r bits is cut out in series from the RS codeword, and so the polynomial is expressed as (4) where ri E GF(2r) and yi signifies a delay of i time units of r bits. The RS-coded sequence R(x) is exactly equal to r(y).…”

Section: Outline Of the Gs Techniquementioning

confidence: 99%

Comparison of Hardware Complexity between Convolutional Guided Scrambling and Galois-Field-Addition Guided Scrambling for Digital Recording.

Kunisa

2000

The Journal of the Institute of Image Information and Televisio

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The guided scrambling (GS) coding technique is used to control the runlength within code blocks, such as d or k, as well as to suppress the DC component. It achieves a code rate very close to the channel capacity. In a GS encoder, a selection set of channel bit streams is constructed by subjecting a source bit stream to several kinds of scramblings and to runlength limited (RLL) coding if necessary. Then one that satisfies the imposed channel constraints best is selected. Typically, the GS technique uses a convolutional operation or an addition operation in the Galois field(GF); these two schemes can generate channel bit streams that meet the channel constraints better than conventional coding techniques. The latter scheme is better in terms of symbol-error probability when both schemes are concatenated with Reed-Solomon (RS) codes.However, nothing is known about the hardware complexity of either scheme. We describe their hardware configurations using ROM tables and compare the table sizes. From this comparison, we conclude that the hardware complexity of the latter scheme is smaller under certain conditions.

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“…[2][3][4]. In this Letter, we adapt and simplify the approach proposed by Zhai et al [4] as we integrate LDPC-CC error control codes with DC-free guided scrambling (GS) constrained sequence codes [5] in such a way that variable-length sequences are supported, and such that EC decoding precedes GS decoding.…”

Section: Introductionmentioning

confidence: 99%

“…1 presents block diagrams of our encoder and decoder. Similar to stand-alone guided scrambling [5], each variable-length source word is prefaced with different patterns of A augmenting bits. The resulting r = 2 A augmented words are then scrambled with a scrambling polynomial d(x) of degree D using the well-known self-synchronizing scrambling technique.…”

Section: Introductionmentioning

confidence: 99%

DC-free LDPC convolutional codes

Frontana

Fair

2013

IEICE ComEX

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Abstract:The use of variable-length error control codes is a natural choice in transmission systems with variable-length data sequences. These systems also employ constrained sequence codes (often called line codes) to ensure that the transmitted symbol sequence is balanced and contains sufficient timing information to facilitate reliable demodulation. We outline how low density parity check convolutional codes (LDPC-CC's) can be integrated with guided scrambling (GS) constrained sequence codes in a manner that supports variable length sequences and limits the detrimental effects of error extension during GS decoding by placing the LDPC-CC decoder before the GS decoder within the receiver. We present spectra and bit error rate results that demonstrate the advantage of this approach. Keywords: DC-free codes, LDPC convolutional codes Classification: Fundamental Theories for Communications References[1] A. Jimenez-Felstrom and K. S. Zigangirov, "Time-varying periodic convolutional codes with low-density parity-check matrix," IEEE Trans.

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Guided scrambling: a new line coding technique for high bit rate fiber optic transmission systems

Abstract: produce Selectively complemented data blocks. A cumula s 1 as a 1 s a 1-2 a Y-s s s tive disparity is then determined between the logical values of different twpe included within ones of the selectivel 56) References Cited of Nat blocks previously encoded into E.

Cited by 87 publications

References 16 publications

Generation of balanced quadrature phase shift keyed sequences through guided scrambling

Generation of balanced quadrature phase shift keyed sequences through guided scrambling

Comparison of Hardware Complexity between Convolutional Guided Scrambling and Galois-Field-Addition Guided Scrambling for Digital Recording.

DC-free LDPC convolutional codes

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