I.J. Fair's research while affiliated with University of Alberta and other places

Publications (106)

Article
Full-text available
We study the ability of recently developed variable-length constrained sequence codes to determine codeword boundaries in the received sequence upon initial receipt of the sequence and if errors in the received sequence cause synchronization to be lost.We first investigate construction of these codes based on the finite state machine description of...
Preprint
Full-text available
Constrained sequence (CS) codes, including fixed-length CS codes and variable-length CS codes, have been widely used in modern wireless communication and data storage systems. Sequences encoded with constrained sequence codes satisfy constraints imposed by the physical channel to enable efficient and reliable transmission of coded symbols. In this...
Article
Full-text available
We consider the construction of capacity-approaching variable-length constrained sequence codes based on multi-state encoders that permit state-independent decoding. Based on the finite state machine description of the constraint, we first select the principal states and establish the minimal sets. By performing partial extensions and normalized ge...
Conference Paper
Full-text available
Constrained sequence codes have been widely used in modern communication and data storage systems. Sequences encoded with constrained sequence codes satisfy constraints imposed by the physical channel, hence enabling efficient and reliable transmission of coded symbols. Traditional encoding and decoding of constrained sequence codes rely on table l...
Article
Full-text available
The use of constrained sequence (CS) codes is important for the robust operation of transmission and data storage systems. While most analysis and development of CS codes has focused on fixedlength codes, recent research has demonstrated advantages of variable-length CS codes. In our design of capacity-approaching variable-length CS codes, the cons...
Preprint
Full-text available
Constrained sequence codes have been widely used in modern communication and data storage systems. Sequences encoded with constrained sequence codes satisfy constraints imposed by the physical channel, hence enabling efficient and reliable transmission of coded symbols. Traditional encoding and decoding of constrained sequence codes rely on table l...
Article
Full-text available
Sequences encoded with Pearson codes are immune to channel gain and offset mismatch that cause performance loss in communication systems. In this paper, we introduce an efficient method of constructing capacity-approaching variable-length Pearson codes. We introduce a finite state machine (FSM) description of Pearson codes, and present a variable-l...
Conference Paper
A novel approach to design capacity-approaching variable-length constrained sequence codes has recently been developed. A critical step in this design process is the construction of minimal sets based on a finite state machine description of the encoders. In this paper we propose three generalized criteria to select the state that will result in co...
Article
We propose using variable-length constrained sequence codes to mitigate inter-cell interference (ICI) in all-bitline flash memory with multi-page programming for single-level cell (SLC), multi-level cell (MLC), and triple-level cell (TLC) flash memory structures. We outline constraints that mitigate ICI in these systems based on an observation of t...
Article
A technique was recently reported to construct high-rate variable-length constrained sequence codes. In this study, the authors outline an algorithm that simplifies the search procedure that is integral to that technique. This algorithm enables examination of a large search space limited only by length and/or number of codewords in order to determi...
Article
Full-text available
The authors outline an approach to construct capacity-approaching balanced quadrature phase shift keyed (QPSK) codes. These codes ensure an equal number of different symbol values and many symbol transitions in the encoded sequence in order to assist practical demodulators to accurately recover symbol values. Their codes are comprised of instantane...
Article
Full-text available
Squared weight is an excellent metric on which to base codeword selection in DC-free multimode coding. It has, however, been considered too complex to implement in practice. In this Letter, the authors present a simple approach to evaluate this metric that enables it to be implemented in high-speed digital logic.
Article
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...
Article
Emerging networks and applications require enormous data storage. Holographic techniques promise high-capacity storage, given resolution of a few remaining technical issues. In this paper, we propose a technique to overcome one such issue: mitigation of large magnitude peaks in the stored image that cause material saturation resulting in readout er...
Article
Constrained sequence codes are widely used to meet constraints imposed by digital communication systems. This study presents methods to evaluate the capacity of constrained codes that have multiple independently or dependently constrained signalling dimensions. The authors outline a straightforward analysis technique when the signalling dimensions...
Article
In holographic data storage, information is recorded within the volume of a holographic medium. Typically, the data is presented as an array of pixels with modulation in amplitude and/or phase. In the 4-f orientation, the Fourier domain representation of the data array is produced optically, and this image is recorded. If the Fourier image contains...
Conference Paper
We consider holographic data storage in which data is represented by an array of pixels with modulation in amplitude and phase, and the Fourier transform of this array is created optically and recorded in a holographic medium. However, if the stored image contains high intensity peaks, the material can saturate, and on readout, the reconstructed da...
Article
Symmetries in the encoding of balanced sequences are exploited to simplify a tabular approach for constructing balanced codes, and it is shown that with appropriate assignment of source word probabilities, these symmetries ensure the absence of discrete components in the spectrum of the encoded signal. He is further shown that assigning appropriate...
Article
The use of spectral shaping constrained codes is commonplace in baseband digital communication systems. In this study, the authors consider the use of constrained codes in bandpass systems through the design of DC-free codes for the complex baseband representations of commonly used signalling constellations including quaternary phase shift keying,...
Article
We outline the construction of simple, high rate constrained sequence codes with variable-length source words and variable-length codewords based on the search of partial extension of a minimal set of codeword lengths. We present optimal word length mappings for a subset of constrained sequence codes, and provide examples of (d, k) and DC-free code...
Article
Coherent optical orthogonal frequency-division multiplexed (OFDM) systems with uniform chromatic dispersion can efficaciously combat both fiber dispersion by utilizing the properties of the cyclic prefix and four-wave mixing (FWM) among the individual subcarriers via the phased-array effect in dispersive fiber links. Such excellent performance, how...
Article
Constrained sequence codes are widely used to meet constraints imposed by digital storage and communication systems. This paper presents several improvements to an algorithm for constructing constrained codes that admit state-independent decoding. We use this improved algorithm to design state-independent decodable DC-free run-length-limited codes.
Article
Multimode coding is a promising coding method owing to the simplicity of its code design and the attainment of high code rate. The authors present a multimode coding scheme for generating two-dimensional balanced t -conservative arrays for holographic storage. The multimode encoding process involves adding each unconstrained input array to a set of...
Article
The authors investigate hybrid automatic repeat request (H-ARQ) schemes for spatially multiplexed multiple-input multiple-output (MIMO) systems with channel state information available only at the receiver. In particular, the authors compare the multiple H-ARQ scheme and the single H-ARQ scheme with repetition. The authors first propose a system mo...
Article
Coherent optical orthogonal frequency-division multiplexed (OFDM) systems must be carefully designed to minimize the detrimental impact of fiber nonlinearity manifested through four-wave mixing (FWM). Because of the small subcarrier spacing associated with OFDM, a significant fraction of FWM processes is well matched, resulting in a rapid buildup o...
Article
Constrained sequence codes are widely used to meet constraints imposed by digital storage and communication systems. This paper develops an algorithm for the construction of constrained codes that admit state-independent decoding. By partitioning the code into a group of alphabets, one for each state, a codebook is developed using this algorithm th...
Article
Coherent optical orthogonal frequency-division multiplexed (OFDM) systems have been shown to be vulnerable to fiber nonlinearity, four-wave mixing (FWM) in particular. Consequently, transmission of OFDM symbols with a low peak-to-average power ratio (PAR) is widely recommended. In this paper, we examine the correlation between PAR and the intensity...
Article
Constrained sequence codes are widely used to help meet constraints imposed by digital storage and communication systems. This paper presents a straightforward approach to evaluate the capacity of constrained sequence codes that are modelled by a two-dimensional finite state machine (FSM) with nearest-neighbour connections. Starting with the equiva...
Article
This paper extends the work on density evolution for binary low-density parity-check (LDPC) codes with Gaussian approximation to LDPC codes over GF(q) . We first generalize the definition of channel symmetry for nonbinary inputs to include q-ary phase-shift keying (PSK) modulated channels for prime q and binary-modulated channels for q that is a po...
Article
In multimode conservative codes for holographic storage, an unconstrained m times n binary array S of source data is added to a set of ( m +1)( n +1) control arrays to form the selection set, which is guaranteed to contain at least one conservative array of strength at least t , such that each row and each column of the output array contain at leas...
Article
Constrained sequence codes and pulse shapes are used to control signal characteristics in digital communication systems. This letter outlines a technique to construct codewords and pulse shapes to meet specified spectral constraints. Based on a block-coded representation of the signal, it is shown how symbol values can be evaluated to satisfy the m...
Article
This paper proposes an extension of Knuthpsilas complementation method for constructing balanced codewords. By placing the encoding process in the context of a multimode code, we propose generating a number of alternative balanced words using Knuthpsilas method to represent each source word, and selecting the word with minimum squared weight (MSW)...
Article
Wireless communication systems usually employ a concatenated error control coding scheme consisting of an outer error detection code and an inner error correction code. Traditionally, these two codes are decoded separately. When the sub-block structure is used, each data block (input sequence) at the inner encoder consists of several sub-blocks and...
Article
Guided scrambling (GS) is a constrained coding technique that can be used in digital communication systems to control the characteristics of the encoded sequence. In each encoding interval, a GS encoder constructs a quotient selection set with a number of codeword candidates and selects the "best" candidate to represent the source word. Relationshi...
Article
Trellis-based error-control (EC) codes, such as convolutional or turbo codes, are integrated with guided scrambling (GS) multimode coding to generate DC-free GS-convolutional/ turbo codes. On the basis of the generators of the convolutional/turbo code, we employ puncturing or flipping to ensure that the EC-coded sequences are DC-free. At the receiv...
Conference Paper
Orthogonal Frequency Division Multiplexing (OFDM) is a promising technique for high bit rate transmission in wireless communications systems. Convolutional coding is often used in conjunction with OFDM to improve the reliability of transmission. However, in this paper, we show that the peak to average power ratio (PAPR) statistics of convolutional...
Article
In digital transmission and storage systems, sequences must have attributes that comply with the physical characteristics of the channel. These channel constraints can often be satisfied through constrained sequence coding techniques which avoid use of sequences that violate the given channel constraints. In the design of a constrained code, it is...
Conference Paper
In order to minimize the interference between adjacent data arrays recorded in the same holographic volume, the patterns of 1's and 0's in each data array should be t- conservative, i.e., for a prescribed integer t, there should be at least t transitions of the form 1 rarr 0 or 0 rarr 1 in each column and row of the data array. In this paper, we pr...
Article
This paper investigates spectrum shaping in ultra-wideband (UWB) communications in order to introduce spectral nulls to limit interference with narrowband signals. Each transmitted symbol is represented by a "coded Gaussian monocycle pulse" in which Gaussian monocycles are weighted, delayed and summed in accordance with a designed codeword. The use...
Conference Paper
Constrained codes are widely used in digital transmission systems and digital recording systems to generate constrained sequences with properties that comply with the given physical characteristics of the transmission or recording channels. The power spectral density (PSD) of encoded signals often plays an important role in the design of constraine...
Article
A list decoder generates a list of more than one codeword candidates, and decoding is erroneous if the transmitted codeword is not included in the list. This decoding strategy can be implemented in a system that employs an inner error correcting code and an outer error detecting code that is used to choose the correct codeword from the list. Probab...
Conference Paper
In this paper the authors investigate the hybrid automatic repeat request (H-ARQ) schemes for spatial multiplexing (SM) multiple-input multiple-output (MIMO) systems with channel state information available only at the receiver (CSIR). In particular, the authors compare the multiple H-ARQ scheme and the single H-ARQ scheme with repetition. The auth...
Conference Paper
In this paper, we develop a selective-repeat automatic-repeat-request (SR-ARQ) transmission scheme for multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexing (OFDM) systems with non-linear preprocessing assuming perfect channel state information at both the transmitter and the receiver. In such a system in every time slot...
Conference Paper
In this paper, a type-II H-ARQ scheme with incremental redundancy is proposed for a turbo coded system that uses the sub-block structure. Sub-block recovery is applied to the decoder and a method to dynamically select the bits for retransmission according to knowledge of the decoding status is proposed. The new scheme benefits from both the frequen...
Conference Paper
In this paper, we compare two selective-repeat automatic-repeat-request (SR-ARQ) protocols for spatial multiplexintiplexingg multiple-input multiple-output (MIMO) orthogonal frequency-division multiplexed (OFDM) systems assuming perfect channel state information (CSI) only at the receiver. These two SR-ARQ protocols differ in the number of packets...
Article
We introduce an extension of Golay complementary sequences in which, for each sequence, there exists another sequence such that the sum of aperiodic autocorrelation functions of these two sequences for a given multiple L-shift (L >= 1) is zero except for the zero shift. We call these sequences multiple L-shift complementary sequences. It is well-kn...
Article
Multimode coding is an efficient block coding technique that introduces control over sequence statistics by generating a number of alternatives to represent the source word in each encoding interval and then selecting the word that best meets the system constraints. The power spectral density (PSD) of the encoded signal is of particular interest wi...
Conference Paper
Line codes (in transmission systems) and recording codes (in magnetic and optical recording systems) are constrained sequence codes used to control the frequency-domain and time-domain characteristics of encoded signals. Pulse shaping is also used to achieve the required signal characteristics in a wide variety of communication systems. In this pap...
Conference Paper
This paper investigates spectrum shaping in ultrawideband (UWB) communications in order to introduce spectral nulls to limit interference with narrowband signals. Each transmitted symbol is represented by a monocycle "coded" Gaussian pulse, where use of the monocycle Gaussian pulse ensures that the UWB spectrum mask established by the Federal Commu...
Article
Irregular low-density parity-check (LDPC) codes have shown exceptionally good performance for single antenna systems over a wide class of channels. In this paper, we investigate their application to multiple antenna systems in flat Rayleigh fading channels. For small transmit arrays, we focus mainly on space-time coding with 2p-ary LDPC codes, wher...
Article
We try to give a qualitative description of the Godbillon-Vey class and its relation on the one hand to the holonomy and on the other hand to the topological entropy of a foliation, using a remarkable theorem proved recently by G. Duminy (which still remains unpublished), relating these three notions in the case of codim-1 foliations. Moreover we s...
Article
Full-text available
Partial transmit sequence (PTS) is a promising technique for peak-to-average-power ratio (PAPR) reduction in orthogonal frequency division multiplexing (OFDM) systems. Computation of optimal PTS weight factors via exhaustive search requires exponential complexity in the number of subblocks; consequently, many suboptimal strategies have been develop...
Article
DC-free codes and error-control (EC) codes are widely used in digital transmission and storage systems. To improve system performance in terms of code rate, bit-error rate (BER), and low-frequency suppression, and to provide a flexible tradeoff between these parameters, this paper introduces a new class of codes with both dc-control and EC capabili...
Conference Paper
Spectral performance of DC-free codes can be evaluated through performance metrics such as sum variance (SV) and low-frequency spectrum weight (LFSW). In this paper we investigate the spectral performance of integrated DC-free error-control codes. Analytical results for estimating the SV and LFSW of these codes are given.
Conference Paper
In multimode constrained coding, in each encoding interval a source word is mapped to multiple channel representatives, one of which is selected to generate sequences with the required constraint(s). In general, multimode codes have been designed to meet single sequence constraints. In this paper, we propose a cascade selection method in multimode...
Article
The minimum squared weight (MSW) criterion has been shown to yield excellent performance for DC-free multimode codes in terms of coding efficiency. However, it is demonstrated that the MSW criterion is not sufficient to guarantee the generation of DC-free sequences. To overcome this drawback, a modified MSW criterion is proposed that integrates the...
Article
Optical disk storage systems use both error control (EC) codes and dc-free constrained sequence (CS) codes in order to increase the reliability of the data read from the disk. We present a method of integrating these coding techniques in order to overcome drawbacks with the conventional manner in which these coding procedures are concatenated. Our...
Article
We analyze the effect of coding parameters on low-frequency suppression in guided scrambling (GS) dc-free codes based on computer simulation. Simple expressions to accurately estimate the sum variance and low-frequency spectrum-weight of these codes are developed. Systematic design of GS dc-free codes is discussed.
Conference Paper
The complexity of conventional partial transmit sequence (PTS) increases largely with the number of subblocks. Conventional PTS requires generation of all partial transmit sequences through IFFT operations and optimization of the weighted partial transmit sequences. Previously published simplification methods only focus on simplifying this optimiza...
Conference Paper
We present a method of integrating constrained sequence (CS) and error control (EC) codes for digital communication systems. This technique is based on multimode coding where a single source word (SW) is represented by a set of complementary EC code words (CWs). From this set the encoder selects the CW that best meets the CS goals of the system. Th...
Conference Paper
In this paper we integrate convolutional/turbo encoding with multimode encoding to generate dc-free convolutional/turbo codes. Based on the generators of error-control codes, we employ flipping or puncturing to ensure that the coded sequences are dc-balanced. At the receiver, the channel output is first decoded by a convolutional/turbo decoder (wit...
Conference Paper
Real-time decoders for turbo codes used in practical applications such as in the WCDMA (UMTS) 3GPP cellular standard are likely to be implemented using fixed-point arithmetic. Requirements for efficient turbo decoders include low-complexity algorithms and small word sizes. The implementation of such a decoder using a modified constant-Log-MAP decod...
Conference Paper
In this paper, theoretical analysis is presented for the sub-block recovery scheme that can be integrated into concatenated error control coding schemes used by communication systems employing hybrid-ARQ. Based on this analysis, we show that if the inner code is a turbo code and iterative sub-optimal decoding is used, the sub-block recovery scheme...
Conference Paper
In this paper, the concepts of effective weight enumerating function and generalized pairwise error event are introduced to predict the performance of linear block codes with list decoding. For the first time, a method to evaluate the actual effective codeword weights for a given code, rather than a lower bound on effective codeword weights, is pro...
Conference Paper
In this paper, we present a new selective mapping (SLM) approach that integrates peak-to-average power ratio (PAPR) reduction with error control (EC) in OFDM systems. We call this new scheme EC-SLM coding. EC-SLM coding has a simple coding structure and does not require transmission of side information. Several well-known linear EC codes such as co...
Conference Paper
DC-free error-control block codes integrate dc-free encoding and error-control block encoding. To reduce the effect of error extension introduced by dc-free decoding and to allow for soft decoding of error-control codes, dc-free error-control block codes are decoded at the receiver by applying error-control decoding techniques prior to dc-free deco...
Conference Paper
The focus of this research work is the sub-optimal list decoding algorithms for parallel concatenated convolutional codes (PCCCs) which improve the frame error rate (FER) performance. Error events and weight spectra for convolutional codes and PCCCs are analyzed with emphasis on their effects on list decoding. We explain the inefficiencies of list...
Article
A new class of codes with high-order spectral s at zero frequency is introduced. The codes, called high-order spectral- multimode codes, are constructed through state-dependent encoding by use of the guided-scrambling coding technique, and result in efficiently coded sequences with good low-frequency characteristics.
Conference Paper
Irregular low-density parity-check (LDPC) codes have shown exceptionally good performance for single antenna systems over a wide class of channels. In this paper, we investigate their application to multiple antenna systems in flat Rayleigh fading channels. For small transmit arrays, we focus mainly on space-time coding with 2<sup>p</sup>-ary LDPC...
Article
Sum-variance is a well-known metric for assessing the performance of dc-free codes (first-order spectral- codes), however, as we show in this paper, it is unsuitable for comparing the magnitude of spectral components of high-order spectral- (HOSN) codes at low frequencies. In this paper, we introduce a new performance metric for evaluating the spec...
Conference Paper
This paper investigate the extension of Golay complementary sequences to a larger family of sequences which we call multiple L-shift complementary sequences ( L 2 I ). It is well-known that the peak-to-average power ratio (PAPR) value of any Golay complementary sequence is less than or equal to 2. We show that the PAPR of each multiple L-shift comp...
Conference Paper
Selective mapping (SLM) and partial transmit sequences (PTS) are two approaches that significantly improve the statistics of the peak-to-average power ratio of an orthogonal frequency-division multiplexing signal. Guided scrambling (GS) is a multimode coding technique that is used to constrain the characteristics of encoded sequences in digital tra...
Article
In this letter, we present three new criteria for early stopping and error detection in turbo decoding. The approaches are based on monitoring the mean of the absolute values of the log-likelihood ratio of the decoded bits, which we show to be directly related to the variance of the metachannel. We demonstrate that this mean value increases as the...
Conference Paper
Irregular low-density parity-check (LDPC) codes have shown exceptional performance for single-antenna systems over AWGN channels. In this paper, we investigate their application in multiple-input multiple-output (MIMO) systems over flat quasi-static Rayleigh fading channels. MIMO systems, with multiple antennas at both ends of the communication lin...
Conference Paper
A new structure for integrating dc-free codes with error control block codes that fully reverses the conventional order of dc-free decoding and error control decoding is proposed. We call these codes dc-free multimode error control block codes.
Conference Paper
We construct DC-free error control coded sequences by guiding convolutional encoders through appropriate augmentation of the source bit stream prior to encoding to ensure that the sequence of error control codewords is balanced. In doing so, we combine the principles of guided scrambling line coding with convolutional error control coding. Decoding...
Conference Paper
We derive a new expression to evaluate the low-frequency spectrum-weight (LFSW) of state-dependent encoded sequences with an arbitrarily high-order spectral at zero frequency. Based on this analysis, a selection criterion for superior suppression of low-frequency components in multimode codes with a spectral at zero frequency is proposed.
Article
We introduce a new method for enumerating codewords that can be applied to DC<sup>2</sup>-constrained channels. Based on this method, two efficient algorithms for evaluating the number of codewords with specified characteristics are developed. Computer calculation results show that these algorithms are significantly more computationally efficient t...
Article
Necessary and sufficient conditions are presented which ensure that base polynomials in guided scrambling line coding generate complementary quotients in all quotient selection sets. The relationship between augmenting bit patterns and complementary quotients is also given
Conference Paper
We show that the systematic component of a terminated recursive systematic convolutional encoder provides a built-in CRC (cyclic redundancy check), and we use this characteristic to improve the performance of the mean-sign-change (MSC) criterion. In addition, we show that by concatenating an external short CRC with the MSC criterion the error detec...
Conference Paper
We introduce a new metric, low-frequency spectrum-weight (LFSW), for evaluating spectrum compression of arbitrarily high-order spectral-null (HOSN) codes around dc. We show that the asymptotic low-frequency spectral components of Mth-order spectral-null codes (dc M-free codes, M&ges;1) are exclusively determined by the order M and the LFSW, and tha...
Article
Guided scrambling (GS) ensures the existence of good line code properties in encoded bit sequences through appropriate augmentation of the source bit stream prior to self-synchronizing scrambling. At the receiver, a framing algorithm is required in order to identify the location of the augmenting bits in the unscrambled bit sequence. This paper pro...
Article
A method for constructing constrained sequences with embedded redundancy for error control is reported. These sequences are constructed such that the first stage of decoding can be performed with standard error control decoding techniques, avoiding the problem of error propagation with prior constrained-sequence decoding
Conference Paper
In this paper we combine techniques for early stopping and error detection in order to stop the iterative turbo code decoding process and detect if errors are present in the decoded bit sequence. The simple and efficient approaches we introduce are based on monitoring the mean of the absolute values of the log-likelihood ratios at the output of the...
Conference Paper
In this paper we present a new method of integrating constrained sequence (CS) and error control (EC) codes for digital communication systems. In our technique, encoded sequences are constructed such that they contain the required redundancy for error control while also exhibiting the characteristics required of constrained sequences. These sequenc...
Article
Convolutional codes are used in digital communication systems to correct errors that occur during transmission. Their use is now commonplace, particularly in power-limited satellite and deep space communication systems. Before the decoder can correctly decode the received continuous bit sequence, however, it must establish where codewords begin and...
Conference Paper
We show that block coded sequences are cycloergodic, and based on this property, we introduce a new nonprobabilistic formula to calculate the average power spectral density of these sequences. We present a new sufficient condition to construct codes with an arbitrarily high-order spectral-null at zero frequency. Given this condition, we outline two...
Conference Paper
High-order spectral-null codes have found practical applications in systems with high-order partial response channels. We derive a necessary and sufficient condition on word length N of Mth-order spectral-null code words, denoted dc<sup>M</sup> words. A new lower bound on the redundancy of dc<sup>M</sup> words is also presented. Furthermore, we inv...
Article
A simple method to perform continuous coding in a guided scrambling (GS) system is presented. This technique reduces the amount of circuitry required to perform the memory updating which is inherent to this operation. A successful implementation has been used in the design of a fully functional GS system
Article
We derive a closed-form expression for the power spectral density of amplitude/phase-shift keyed bit sequences randomized through self-synchronizing scrambling when the source sequence is a stationary sequence of statistically independent bits. In addition to the dependence on the symbol pulse shape, duration, and the signal space values with which...
Conference Paper
The guided scrambling (GS) line coding technique was introduced by Fair, Grover, Krzymien, and MacDonald (1991) as a novel mechanism to ensure that binary transmitted sequences exhibit desirable line code characteristics. We describe a field programmable gate array (FPGA) implementation of GS. The system accommodates code words of up to 32 bits in...
Article
The authors develop a practical method of evaluating the power spectral density of guided scrambling line-coded sequences. Analysis of block-coded signals is reviewed, and it is shown that it is impractical to analyse continuous guided scrambling coded sequences with expressions presented elsewhere in the literature. Alternative expressions for seq...
Article
We derive several properties of guided scrambling (GS) encoders and the sequences they generate. We first highlight symmetrical aspects of the GS encoding mechanisms proposed to date, and then show that the existence of discrete components in the power spectrum of the pulse-amplitude-modulated encoded sequence can be predicted from the weight of th...
Article
We present a framing method for the guided scrambling (GS) line code. It is modeled using a random walk with a reflecting barrier at one end and an absorption barrier at the other. The method is based on the statistical analysis of the encoded data stream. Results for a (3,4) block GS scheme are presented which compare in-frame and out-of-frame val...
Article
Guided scrambling (GS) is a line coding technique developed specifically for high bit rate fiber optic transmission systems. This paper continues the development of GS coding by introducing more scrambling polynomials that can be used with this technique. First, a method is presented for constructing polynomials which can be used with balanced enco...
Article
Guided scrambling (GS) line codes augment the source bit stream prior to self-synchronizing scrambling to ensure that the scrambling process generates an encoded bit sequence with good line code characteristics. With arithmetic from the ring of polynomials over GF(2), self-synchronizing scrambling can be interpreted as division of the source bit se...

Citations