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Showing papers in "IEEE Transactions on Communications in 1993"


Journal Article•DOI•
TL;DR: The author describes the fundamental equation for interpolation, proposes a method for control, and outlines the signal-processing characteristics appropriate to an interpolator.
Abstract: Timing adjustment in a digital modem must be performed by interpolation if sampling is not synchronized to the data symbols. The author describes the fundamental equation for interpolation, proposes a method for control, and outlines the signal-processing characteristics appropriate to an interpolator. A review of previous results and a tutorial exposition of the subject are given, along with new results. >

706 citations


Journal Article•DOI•
TL;DR: The NCO-based control method presented in Part I is shown to be equivalent to a conventional phase locked loop and its operation is verified by simulation, demonstrating that simple interpolators give excellent performance.
Abstract: For pt.I, see ibid., vol.41, no.3, p.502-208 (1993). Properties of a specific class of interpolators that are based upon polynomials are discussed. Several implementations are described, one of which is particularly convenient in practical hardware. Simulations demonstrate that simple interpolators give excellent performance. In many cases, two-point, linear interpolation is adequate. If better performance is needed, classical four-point, third-order polynomials could be used. Better yet, a novel four-point interpolating filter with piecewise-parabolic impulse response can have performance superior to that of the standard cubic interpolator and still be implemented much more simply. The NCO-based control method presented in Part I is shown to be equivalent to a conventional phase locked loop and its operation is verified by simulation. >

640 citations


Journal Article•DOI•
TL;DR: It is shown that performance gains with respect to the linear decorrelating detector are more significant for relatively weak users and that the error probability of the weakest user approaches the single-user bound as interferers grow stronger.
Abstract: A decorrelating decision-feedback detector (DF) for synchronous code-division multiple-access (CDMA) that uses decisions of the stronger users when forming decisions for the weaker ones is described. The complexity of the DF is linear in the number of users, and it requires only one decision per user. It is shown that performance gains with respect to the linear decorrelating detector are more significant for relatively weak users and that the error probability of the weakest user approaches the single-user bound as interferers grow stronger. The error rate of the DF is compared to those of the decorrelator and the two-stage detector. >

564 citations


Journal Article•DOI•
TL;DR: A combination of discrete-event link simulation and analysis of the obtained SIR statistics is used to explore the previously little-known behavior of a CDMA system using SIR-based power control and to obtain performance estimates for such a system under various operating assumptions.
Abstract: For pt.I see ibid., vol 41, p.1626-34 (1993). Power control is essential in the use of direct-sequence code division multiple-access (CDMA) techniques. Early system-level performance analyses of a CDMA approach to wireless mobile and personal communications have assumed the ability of power control to equalize the absolute signal powers of CDMA users received at each base station. The present paper studies a more practical, although analytically more complicated, uplink power control technique that uses measurements of the received signal-to-interference ratio (SIR) instead. A combination of discrete-event link simulation and analysis of the obtained SIR statistics is used to explore the previously little-known behavior of a CDMA system using SIR-based power control and to obtain performance estimates for such a system under various operating assumptions. The overall results indicate that power control based on SIR has the potential for somewhat higher system performance than power control based on absolute signal strength assumed in the early analyses. >

369 citations


Journal Article•DOI•
TL;DR: A three-state technique for reliable displacement estimation with fractional-pel accuracy is introduced, based on phase correlation, and for motion-compensation with block size of 16 pels*16 pels, 1/4- Pel accuracy appears to be sufficient for broadcast TV signals, whereas for videophone signals,1/2-pel Accuracy is desirable.
Abstract: The effect of fractional-pel accuracy on the efficiency of motion-compensating predictors is studied using various spatial prediction/interpolation filters. In model calculations, the power spectral density of the prediction error is related to the probability density function of the displacement error. Prediction can be improved both by higher accuracy of motion-compensation and by spatial Wiener filtering in the predictor. Beyond a critical accuracy, the possibility of further improving prediction by more accurate motion-compensation is small. Experiments with videophone signals and with broadcast TV signals confirm these model calculations. Sinc-interpolation, bilinear interpolation, and Wiener filtering are compared at integer-pel, 1/2-pel, 1/4-pel, and 1/8-pel accuracies. A three-state technique for reliable displacement estimation with fractional-pel accuracy is introduced. It is based on phase correlation. For motion-compensation with block size of 16 pels*16 pels, 1/4-pel accuracy appears to be sufficient for broadcast TV signals, whereas for videophone signals, 1/2-pel accuracy is desirable. >

346 citations


Journal Article•DOI•
TL;DR: The proposed algorithm uses the smoothness property of common image signals and produces a maximally smooth image among all those with the same coefficients and boundary conditions and recovers each damaged block by minimizing the intersample variation within the block and across the block boundary.
Abstract: The authors consider the reconstruction of images from partial coefficients in block transform coders and its application to packet loss recovery in image transmission over asynchronous transfer mode (ATM) networks. The proposed algorithm uses the smoothness property of common image signals and produces a maximally smooth image among all those with the same coefficients and boundary conditions. It recovers each damaged block by minimizing the intersample variation within the block and across the block boundary. The optimal solution is achievable through two linear transformations, where the transform matrices depend on the loss pattern and can be calculated in advance. The reconstruction of contiguously damaged blocks is accomplished iteratively using the previous solution as the boundary conditions in each new step. This technique is applicable to any unitary block-transform and is effective for recovering the DC and low-frequency coefficients. When applied to still image coders using the discrete cosine transform (DCT), high quality images are reconstructed in the absence of many DC and low-frequency coefficients over spatially adjacent blocks. When the damaged blocks are isolated by block interleaving, satisfactory results have been obtained even when all the coefficients are missing. >

343 citations


Journal Article•DOI•
L.-F. Wei1•
TL;DR: Two approaches for providing unequal error protection to different classes of data are presented and can provide error protection for the important data to an extent that can hardly be achieved using conventional coded modulation with equal error protection.
Abstract: It is always desirable to maintain communications in difficult situations, even though fewer messages can get across. The author has developed such capabilities for one-way broadcast media, such as the envisioned terrestrial broadcasting of digital high-definition television signals. In this television broadcasting, the data from video source encoders are not equally important. It is desirable that the important data be recovered by each receiver even under poor receiving conditions. Two approaches for providing such unequal error protection to different classes of data are presented. Power-efficient and bandwidth-efficient coded modulation is used in both approaches. The first approach is based on novel signal constellations with nonuniformly spaced signal points. The second uses time division multiplexing of different conventional coded modulation schemes. Both approaches can provide error protection for the important data to an extent that can hardly be achieved using conventional coded modulation with equal error protection. For modest amounts of important data, the first approach has, additionally, the potential of providing immunity from impulse noise through simple bit or signal-point interleaving. >

298 citations


Journal Article•DOI•
TL;DR: Performance of a wideband multipath-fading terrestrial digital coded communication system with applications to a cellular system using direct-sequence spread-spectrum code-division multiaccess (CDMA) with M-ary orthogonal modulation on the many-to-one reverse link.
Abstract: Performance of a wideband multipath-fading terrestrial digital coded communication system is treated. The analysis has applications to a cellular system using direct-sequence spread-spectrum code-division multiaccess (CDMA) with M-ary orthogonal modulation on the many-to-one reverse (user-to-base station) link. For these links, power control of each multiple-access user by the cell base station is a critically important feature. This feature is implemented by measuring the power received at the base station for each user and sending a command to either raise or lower reverse link transmitter power by a fixed amount. Assuming perfect interleaving, the effect of the power control accuracy on the system performance is assessed. >

279 citations


Journal Article•DOI•
L. Hu1•
TL;DR: Simulations show that the final topology is degree-bounded, has a rather regular and uniform structure, and has throughput and reliability that are greater than that of a number of alternative topologies.
Abstract: A distributed topology-control algorithm has been developed for each node in a packet radio network (PRN) to control its transmitting power and logical neighbors for a reliable high-throughput topology. The algorithm first constructs a planar triangulation from locations of all nodes as a starting topology. Then, the minimum angles of all triangles in the planar triangulation are maximized by means of edge switching to improve connectivity and throughput. The resulting triangulation at this stage, the Delaunay triangulation, can be determined locally at each node. The topology is modified by negotiating among neighbors to satisfy a design requirement on the nodal degree parameter. Simulations show that the final topology is degree-bounded, has a rather regular and uniform structure, and has throughput and reliability that are greater than that of a number of alternative topologies. >

275 citations


Journal Article•DOI•
Israel Cidon1, Yoram Ofek1•
TL;DR: The design principles of a ring network with spatial bandwidth reuse, a reliable fairness mechanism, and the exploitation of advent in fiber-optic technology are described, which are the basis for the MetaRing network architecture.
Abstract: The design principles of a ring network with spatial bandwidth reuse are described. A distributed fairness mechanism for this architecture, which uses low latency hardware control signals, is presented. The basic fairness mechanism can be extended for implementing multiple priority levels and integration of asynchronous with synchronous traffic. The ring is full-duplex and has two basic modes of operation: buffer insertion mode for variable-size packets and slotted mode for fixed-size packets or cells. Concurrent access and spatial reuse allow simultaneous transmissions over disjoint segments of a bidirectional ring and can increase the effective throughput by a factor of four or more. The combination of a full-duplex ring, spatial reuse, a reliable fairness mechanism, and the exploitation of advent in fiber-optic technology are the basis for the MetaRing network architecture. >

269 citations


Journal Article•DOI•
TL;DR: The theory of optimum FRESH filtering, which is a generalization of Wiener filtering called cyclicWiener filtering, is summarized, and the theory is illustrated with specific examples of separating temporally and spectrally overlapping communications signals, including AM, BPSK, and QPSK.
Abstract: Conventional time and space filtering of stationary random signals, which amounts to forming linear combinations of time translates and space translates, exploits the temporal and spatial coherence of the signals. By including frequency translates as well, the spectral coherence that is characteristic of cyclostationary signals can also be exploited. Some of the theoretical concepts underlying this generalized type of filtering, called frequency-shift (FRESH) filtering, are developed. The theory of optimum FRESH filtering, which is a generalization of Wiener filtering called cyclic Wiener filtering, is summarized, and the theory is illustrated with specific examples of separating temporally and spectrally overlapping communications signals, including AM, BPSK, and QPSK. The structures and performances of optimum FRESH filters are presented, and adaptive adjustment of the weights in these structures is discussed. Also, specific results on the number of digital QAM signals that can be separated, as a function of excess bandwidth, are obtained. >

Journal Article•DOI•
TL;DR: A channel coding approach called diversity coding is introduced for self-healing and fault-tolerance in digital communication networks for nearly instantaneous recovery from link failures.
Abstract: A channel coding approach called diversity coding is introduced for self-healing and fault-tolerance in digital communication networks for nearly instantaneous recovery from link failures. To achieve this goal, the problem of link failures is treated as an erasure channel problem. Implementation details of this technique in existing and future communication networks are discussed. >

Journal Article•DOI•
Wai-Man Lam, Amy R. Reibman1•
TL;DR: The authors restrict the local processors to be quantizers and consider the optimal design of the systems to minimize the estimation error based on the Bayes distortion functions and Fisher's information.
Abstract: The authors consider parameter estimation in decentralized systems with distributed processors. They restrict the local processors to be quantizers and consider the optimal design of the systems to minimize the estimation error. They present necessary conditions for the optimal system based on the Bayes distortion functions and Fisher's information. The numerical results compare the resulting quantizers obtained by different distortion criteria. >

Journal Article•DOI•
TL;DR: A class of loss networks in which each connection specifies a route and a bandwidth requirement is considered, and the approximations are shown to be asymptotically correct in a natural limiting regime.
Abstract: A class of loss networks in which each connection specifies a route and a bandwidth requirement is considered. If sufficient bandwidth is not available in one of the links along the route, the connection is blocked and lost. Three schemes are considered for approximating blocking probabilities in the network. For a specific star topology, two of these schemes give blocking probabilities that are very close to the exact values under light, moderate, and heavy traffic. The approximations are shown to be asymptotically correct in a natural limiting regime. The implied costs and their relation to revenue sensitivity are also determined for the approximation schemes. The approximate revenue sensitivities are again very close to the exact values for the specific star topology. >

Journal Article•DOI•
TL;DR: Optimality properties of likelihood-ratio quantizers are established for a very broad class of quantization problems, including problems involving the maximization of an Ali-Silvey (1966) distance measure and the Neyman-Pearson variant of the decentralized detection problem.
Abstract: M hypotheses and a random variable Y with a different probability distribution under each hypothesis are considered. A quantizer is applied to form a quantized random variable gamma (Y). The extreme points of the set of possible probability distributions of gamma (Y), as gamma ranges over all quantizers, is characterized. Optimality properties of likelihood-ratio quantizers are established for a very broad class of quantization problems, including problems involving the maximization of an Ali-Silvey (1966) distance measure and the Neyman-Pearson variant of the decentralized detection problem. >

Journal Article•DOI•
G. Feygin1, P.G. Gulak1•
TL;DR: This work extends previously known traceback approaches, describes two new traceback algorithms, and compares various traceback methods with each other.
Abstract: In a Viterbi decoder, there are two known memory organization techniques for the storage of survivor sequences from which the decoded information sequence is retrieved, namely, register exchange method and traceback method. This work extends previously known traceback approaches, describes two new traceback algorithms, and compares various traceback methods with each other. Memory size, latency, and implementational complexity of the survivor sequence management are analyzed for both uniprocessor and multiprocessor realizations of Viterbi decoders. A new, one-pointer traceback method is shown to be better than previously known traceback methods. >

Journal Article•DOI•
TL;DR: In this paper, a determinate state convolutional code is formed from a conventional CNN by pruning away some of the possible state transitions in the decoding trellis, which is an extremely efficient way of enhancing the performance of a concatenated coding system.
Abstract: A determinate state convolutional code is formed from a conventional convolutional code by pruning away some of the possible state transitions in the decoding trellis. This staged power transfer proves to be an extremely efficient way of enhancing the performance of a concatenated coding system. The authors analyze the decoding complexity and free distances of these new codes, determine some important statistical properties of the decoder output, and provide simulation results for performance at the low signal-to-noise ratios where a real communications system would operate. Several concise, practical examples are presented. >

Journal Article•DOI•
J. Ward1, R.T. Compton1•
TL;DR: It is shown how an MBAA can be integrated into a single-hop slotted ALOHA packet radio system, and the resulting throughput is analyzed for both finite- and infinite-user populations.
Abstract: The authors consider the use of a multiple-beam adaptive array (MBAA) in a packet radio system. In an MBAA, a given set of antenna elements is used to form several antenna patterns simultaneously. When it is used in a packet radio system, an MBAA can successfully receive two or more overlapping packets at the same time. Each beam captures a different packet by automatically pointing its pattern toward one packet while nulling other, contending packets. It is shown how an MBAA can be integrated into a single-hop slotted ALOHA packet radio system, and the resulting throughput is analyzed for both finite- and infinite-user populations. >

Journal Article•DOI•
TL;DR: Using this method implemented on a high-speed special-purpose processor, several classes of cyclic redundancy-check (CRC) codes with 24 and 32 parity bits are investigated and the d/sub min/ profiles of the resulting codes are presented and compared with recent suggestions.
Abstract: The method developed by T. Fujiwara et al. (1985) for efficiently computing the minimum distance of shortened Hamming codes using the weight distribution of their dual codes is extended to treat arbitrary shortened cyclic codes. Using this method implemented on a high-speed special-purpose processor, several classes of cyclic redundancy-check (CRC) codes with 24 and 32 parity bits are investigated. The CRC codes of each class are known to have the same minimum distance d/sub min.L/ in a certain range L of block lengths n, and within each class that CRC code has been determined the minimum distance of which exceeds d/sub min.L/ up to the largest block length. The d/sub min/ profiles of the resulting codes are presented and compared with the d/sub min/ profiles of recent suggestions of P. Merkey and E. C. Posner (1984), as well as with the d/sub min/ profile of the widely used 32 parity-bit standard code recommended in IEEE-802. >

Journal Article•DOI•
TL;DR: An approach to congestion control based on open-loop regulation of the input is investigated, and the tradeoff between the smoothness of the departure process and packet waiting time is studied.
Abstract: An approach to congestion control based on open-loop regulation of the input is investigated. The input rate regulation schemes are studied from the viewpoint of their smoothing and regulating effects on the incoming traffic. The smoothing effect is characterized by the variance of the interdeparture time of the packet departure process from the input rate regulation mechanism. Under the assumption of Poisson arrivals the characteristics of this departure process are explicitly derived in terms of the particular scheme's parameters, and the tradeoff between the smoothness of the departure process and packet waiting time is studied. Results for both finite- and infinite-buffer pool sizes are presented. >

Journal Article•DOI•
TL;DR: An estimator that combines a suboptimum tree-search algorithm with a recursive least-squares estimator of complex signal amplitude is considered, and its performance is very close to that of the joint maximum-likelihood receiver.
Abstract: The problem of simultaneously detecting the information bits and estimating signal amplitudes and phases in a K-user asynchronous direct-sequence spread-spectrum multiple-access communication system is addressed. The joint maximum-likelihood (ML) estimator has a computational complexity that is exponential in the total number of bits transmitted and thus does not represent a practical solution to the problem. An estimator that combines a suboptimum tree-search algorithm with a recursive least-squares estimator of complex signal amplitude is considered. The complexity of this estimator is O(K/sup 2/) computations per decoded bit, and its performance is very close to that of the joint ML receiver. This receiver has the advantage that the transmitted signal powers and phases are extracted from the received signal in an adaptive fashion without using a test sequence. >

Journal Article•DOI•
TL;DR: The uplink and downlink performance of a digital cellular radio system that uses direct sequence code division multiple access is evaluated and the RAKE receivers are shown to improve the performance significantly, except when the channel consists of a single faded path.
Abstract: The uplink and downlink performance of a digital cellular radio system that uses direct sequence code division multiple access is evaluated. Approximate expressions are derived for the area averaged bit error probability while accounting for the effects of path loss, log-normal shadowing, multipath-fading, multiple-access interference, and background noise. Three differentially coherent receivers are considered: a multipath rejection receiver, a RAKE receiver with predetection selective diversity combining, and a RAKE receiver with postdetection equal gain combining. The RAKE receivers are shown to improve the performance significantly, except when the channel consists of a single faded path. Error correction coding is also shown to substantially improve the performance, except for slowly fading channels. >

Journal Article•DOI•
Noboru Endo1, Takahiko Kozaki1, T. Ohuchi1, H. Kuwahara, Shinobu Gohara1 •
TL;DR: The resultant estimate shows that buffer sharing reduces the necessary buffer memory to less than 1/5 of what would otherwise be required, and the required buffer size is about 128 cells/output for a 32*32 switch when considering bursty traffic conditions.
Abstract: An asynchronous transfer mode (ATM) switch architecture called a shared buffer memory switch whose output cell buffers are shared among all the output ports of the switch is proposed. Experimental measurements and a discussion about the traffic characteristics of the switch architecture are carried out to determine how much buffer memory will be reduced through buffer sharing under various traffic conditions and to roughly estimate how many buffers are needed for the switch to meet certain requirements. The resultant estimate shows that buffer sharing reduces the necessary buffer memory to less than 1/5 of what would otherwise be required, and the required buffer size is about 128 cells/output for a 32*32 switch when considering bursty traffic conditions. LSI implementation is also discussed to show that a 32*32 switch can be composed of about 12 chips mounted on one printed board. >

Journal Article•DOI•
TL;DR: The problem of the algebraic construction of a particular family of optical codes for use in code-division multiple-access (CDMA) fiber-optic local area networks (LANs) is treated, and it is shown that p-1 codes exist for every odd prime p and can serve as many as p- 1 different users in the CDMA fiber- optic system.
Abstract: The problem of the algebraic construction of a particular family of optical codes for use in code-division multiple-access (CDMA) fiber-optic local area networks (LANs) is treated. The conditions that the code families have to satisfy when used in such systems are reviewed. The new codes are called quadratic congruence codes, and the construction of the corresponding sequences is based on the number-theoretic concept of quadratic congruences. It is shown that p-1 codes exist for every odd prime p and can serve as many as p-1 different users in the CDMA fiber-optic system. The codes belong to the family of optical orthogonal codes, their auto- and cross-correlation properties are established, and their performance is compared to that of the previous optical codes. Examples of the codes and examples of their auto- and cross-correlation functions are given. >

Journal Article•DOI•
Nambi Seshadri1, C.-E. Sundberg1•
TL;DR: The authors present coded 8-phase-shift-keyed (8-PSK) modulations for the Rayleigh fading channel and a suboptimal multistage decoder that utilizes interstage interleaving and iterative decoding is proposed and evaluated.
Abstract: The authors present coded 8-phase-shift-keyed (8-PSK) modulations for the Rayleigh fading channel. The schemes are based on multilevel trellis-coded-modulation constructions and utilize maximum free Hamming distance binary convolutional codes as building blocks. A suboptimal multistage decoder that utilizes interstage interleaving and iterative decoding is proposed and evaluated. Examples are constructed to show that the proposed schemes outperform the best modified codes of the Ungerboeck type due to significantly higher implicit time diversity, yielding seven branches of built-in time diversity, whereas the Ungerboeck code yields four branches of time diversity for a 64-state system. The transmission delay is higher, however. The new schemes can provide three levels of unequal error protection when 8-PSK or 8-differential-phase-shift-keying (8-DPSK) modulations are used. They provide 10-14-dB channel signal-to-noise ratio gain over uncoded 4-DPSK at a bit error rate of 10/sup -3/ for a modest decoding complexity. >

Journal Article•DOI•
TL;DR: It is shown that there is a dichotomy in network behavior: if the offered traffic is below a threshold, then the network loss probability decreases exponentially with increasing network size, and above the threshold, performance is poor.
Abstract: The aggregated-least-busy-alternative (ALBA), a distributed, state-dependent, dynamic routing strategy for circuit-switched loss networks is discussed. The networks considered are symmetric and fully connected. The offered calls form Poisson streams, and routes have at most two links. In ALBA(K), the states of each link are lumped into K (K>or=2) aggregates, and the route of each call is determined by local information on the aggregate states of the links of the alternate routes at the time of the call's arrival. The last aggregate is always the set of states reserved for direct traffic. A fixed-point model for ALBA(K) for general K is presented. The particular case of ALBA in which there is no aggregation is least busy alternative (LBA); ALBA(2) represents the other extreme of aggregation. Simulation and analytic results for LBA are compared. An asymptotic scaling based on the fixed-point models is also discussed. It is shown that there is a dichotomy in network behavior: if the offered traffic is below a threshold, then the network loss probability decreases exponentially with increasing network size, and above the threshold, performance is poor. >

Journal Article•DOI•
TL;DR: The authors describe a noncoherent all-digital delay lock loop (DDLL) suited for chip timing synchronization in band-limited direct sequence spread spectrum (DS/SS) systems, and they thoroughly analyze its performance.
Abstract: Migration towards a full-digital implementation of modems is currently one of the main trends in transmission systems design. The authors describe a noncoherent all-digital delay lock loop (DDLL) suited for chip timing synchronization in band-limited direct sequence spread spectrum (DS/SS) systems, and they thoroughly analyze its performance. The key features of this novel scheme are represented by its low-complexity processing section together with its good tracking capability. Analytical expressions for the DDLL S-curve and steady-state timing jitter are derived and confirmed by a time-domain computer simulation. Furthermore, the Mean Time to Lose Lock (MTLL) of the loop is evaluated and some numerical results are reported. The proposed chip timing synchronization scheme reveals also an improved tracking performance when compared to the traditional analog DLL for rectangular chip DS/SS signals. >

Journal Article•DOI•
TL;DR: The authors examine maximum-likelihood block detection of uncoded full response continuous phase modulation over an additive white Gaussian noise (AWGN) channel and finds many new receiver structures that can be compared to the traditional ones that have been used in the past.
Abstract: The authors examine maximum-likelihood block detection of uncoded full response continuous phase modulation (CPM) over an additive white Gaussian noise (AWGN) channel. Both the maximum-likelihood metrics and the bit error probability performances of the associated detection algorithms are considered. The special and popular case of minimum-shift-keying (MSK) corresponding to h=0.5 and constant amplitude frequency pulse is treated separately. The many new receiver structures that result from this investigation can be compared to the traditional ones that have been used in the past both from the standpoint of simplicity of implementation and optimality of performance. >

Journal Article•DOI•
TL;DR: One key discovery is that when channel errors are dependent, selective-repeat ARQ achieves the same throughput efficiency as that in independent channel errors.
Abstract: The performance of automatic-repeat-request (ARQ) protocols which are affected by nonindependent channel errors is studied. The protocols are the three basic ARQ protocols: stop-and-wait, go-back-N, and selective-repeat. Two types of nonindependent channel errors are considered: the kth-order Markovian errors and the gap errors. Both throughput efficiency and packet delay are obtained. The validity of analysis is verified by computer simulations. One key discovery is that when channel errors are dependent, selective-repeat ARQ achieves the same throughput efficiency as that in independent channel errors. >

Journal Article•DOI•
TL;DR: In this paper, a precoding scheme for noise whitening on intersymbol interference (ISI) channels is presented, which is compatible with trellis-coded modulation and, unlike Tomlinson precoding, allows constellation shaping.
Abstract: A precoding scheme for noise whitening on intersymbol interference (ISI) channels is presented. This scheme is compatible with trellis-coded modulation and, unlike Tomlinson precoding, allows constellation shaping. It can be used with almost any shaping scheme, including the optimal SVQ shaping, as opposed to trellis precoding, which can only be used with trellis shaping. The implementation complexity of this scheme is minimal-only three times that of the noise prediction filter, hence effective noise whitening can be achieved by using a high-order predictor. >