The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Shlomo Shamai - One of the best experts on this subject based on the ideXlab platform.
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on the capacity of the dirty paper channel with fast Fading and discrete channel states
International Symposium on Information Theory, 2016Co-Authors: Stefano Rini, Shlomo ShamaiAbstract:Interference pre-cancellation as in the “writing onto dirty paper” channel crucially depends on the transmitter having exact knowledge of the way in which input and channel state combine to produce the channel output. The presence of even a small amount of uncertainty in such knowledge, gravely hampers the ability of the encoder to pre-code its transmissions against the channel state. This is particularly disappointing as it implies that interference pre-coding in practical systems is effective only when the channel estimates have very high precision, a condition which is generally unattainable in wireless environments. In this paper we show that state decoding, instead of state pre-cancellation, can be approximately optimal for a channel with discrete states when only partial channel knowledge is available. More specifically, we consider a variation of the “writing onto dirty paper” channel in which a discrete-valued state sequence is multiplied by a fast Fading process and derive conditions on the Fading Distribution for which state decoding closely approaches capacity. This channel model is a special case of the Gelf'and-Pinsker channel and our results show an instance of this problem in which state decoding is approximately optimal.
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on capacity of the writing onto fast Fading dirt channel
arXiv: Information Theory, 2016Co-Authors: Stefano Rini, Shlomo ShamaiAbstract:The "Writing onto Fast Fading Dirt" (WFFD) channel is investigated to study the effects of partial channel knowledge on the capacity of the "writing on dirty paper" channel. The WFFD channel is the Gel'fand-Pinsker channel in which the output is obtained as the sum of the input, white Gaussian noise and a Fading-times-state term. The Fading-times-state term is equal to the element-wise product of the channel state sequence, known only at the transmitter, and a fast Fading process, known only at the receiver. We consider the case of Gaussian distributed channel states and derive an approximate characterization of capacity for different classes of Fading Distributions, both continuous and discrete. In particular, we prove that if the Fading Distribution concentrates in a sufficiently small interval, then capacity is approximately equal to the AWGN capacity times the probability of this interval. We also show that there exists a class of Fading Distributions for which having the transmitter treat the Fading-times-state term as additional noise closely approaches capacity. Although a closed-form expression of the capacity of the general WFFD channel remains unknown, our results show that the presence of Fading can severely reduce the usefulness of channel state knowledge at the transmitter.
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on the dirty paper channel with fast Fading dirt
International Symposium on Information Theory, 2015Co-Authors: Stefano Rini, Shlomo ShamaiAbstract:Costa's “writing on dirty paper” result establishes that full state pre-cancellation can be attained in the Gel'fand-Pinsker problem with additive state and additive white Gaussian noise. This result holds under the assumptions that full channel knowledge is available at both the transmitter and the receiver. In this work we consider the scenario in which the state is multiplied by an ergodic Fading process which is not known at the encoder. We study both the case in which the receiver has knowledge of the Fading and the case in which it does not: for both models we derive inner and outer bounds to capacity and determine the distance between the two bounds when possible. For the channel without Fading knowledge at either the transmitter or the receiver, the gap between inner and outer bounds is finite for a class of Fading Distributions which includes a number of canonical Fading models. In the capacity approaching strategy for this class, the transmitter performs Costa's pre-coding against the mean value of the Fading times the state while the receiver treats the remaining signal as noise. For the case in which only the receiver has knowledge of the Fading, we determine a finite gap between inner and outer bounds for two classes of discrete Fading Distribution. The first class of Distributions is the one in which there exists a probability mass larger than one half while the second class is the one in which the Fading is uniformly distributed over values that are exponentially spaced apart. Unfortunately, the capacity in the case of a continuous Fading Distribution remains very hard to characterize.
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intersymbol interference with flat Fading channel capacity
International Symposium on Information Theory, 2008Co-Authors: Antonia M Tulino, Sergio Verdu, Giuseppe Caire, Shlomo ShamaiAbstract:This paper finds the capacity of a linear time-invariant system with a given transfer function, observed in additive Gaussian noise through a memoryless Fading channel. A coherent model is assumed where the Fading coefficients are known at the receiver (but not the transmitter). We show that the optimum normalized power spectral density is the waterfilling solution for reduced signal-to-noise ratio, where the gap to the actual signal-to-noise ratio depends on both the Fading Distribution and the channel transfer function.
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achievable rates with imperfect transmitter side information using a broadcast transmission strategy
IEEE Transactions on Wireless Communications, 2008Co-Authors: A Steiner, Shlomo ShamaiAbstract:rdquoWe investigate the performance of the broadcast approach for various Fading Distributions, which correspond to different models of partial transmit channel state information (CSI). The first model considered is the quantized limited feedback. In this model, the receiver can send as feedback only a finite number of bits describing the Fading gain. We derive the optimal power allocation for the broadcast approach for the quantized feedback model. For a Rayleigh Fading channel, numerical results here show that if the feedback word can be longer than one bit, the broadcasting gain becomes negligible, due to diminished channel uncertainty. The second partial transmit CSI model is a stochastic Gaussian model with mean and variance information, which is commonly used for modeling the channel estimation error. In a single-input single-output (SISO) channel, this model also corresponds to the Ricean Fading Distribution, for which we derive maximal achievable broadcasting rates. We further consider a multiple-input single-output (MISO) channel, and derive the optimal power allocation strategy in a broadcast approach. Numerical results here show that uniform power allocation is preferable over beamforming power allocation in the region where broadcasting gain over single level coding is non-negligible.
Daniel Benevides Da Costa - One of the best experts on this subject based on the ideXlab platform.
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the α η κ f composite Fading Distribution
IEEE Wireless Communications Letters, 2020Co-Authors: Osamah S Badarneh, Sami Muhaidat, Daniel Benevides Da CostaAbstract:In this letter, a new general composite Fading model, namely $\alpha $ - $\eta $ - $\kappa $ - $\mathcal {F}$ model, is proposed. It considers most of the well-known propagation phenomena in wireless Fading channels, such as shadowing, multi-path Fading, non-linearity of the propagation medium, power of the dominant components, and power of the scattered waves. Additionally, most of the important statistical Fading models are included in the $\alpha $ - $\eta $ - $\kappa $ - $\mathcal {F}$ model as special cases. The envelope probability density function (PDF) and cumulative Distribution function (CDF) are derived and then employed to derive the PDF and CDF of the instantaneous signal-to-noise ratio. The performance of a wireless communication system operating under the $\alpha $ - $\eta $ - $\kappa $ - $\mathcal {F}$ composite model is evaluated in terms of outage probability and symbol error rate. Numerical results are supported by Monte-Carlo simulations to validate the analysis.
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the alpha k µ shadowed Fading Distribution statistical characterization and applications
Global Communications Conference, 2019Co-Authors: Pablo Ramirezespinosa, Daniel Benevides Da Costa, Jules M Moualeu, Javier F LopezmartinezAbstract:We introduce the /spl alpha/-/spl kappa/-/spl mu/ shadowed (/spl alpha/-KMS) Fading Distribution as a natural generalization of the versatile /spl alpha/-/spl kappa/-/spl mu/ and /spl alpha/-/spl eta/-/spl mu/Distributions. The /spl alpha/-KMS Fading Distribution unifies a wide set of Fading Distributions, as it includes the /spl alpha/-/spl kappa/-/spl mu/, /spl alpha/-/spl eta/-/spl mu/, /spl alpha/-/spl mu/, Weibull, /spl kappa/-/spl mu/ shadowed, Rician shadowed, /spl kappa/-/spl mu/ and /spl eta/-/spl mu/ Distributions as special cases, together with classical models like Rice, Nakagami-m, Hoyt, Rayleigh and one-sided Gaussian. Notably, the /spl alpha/-KMS Distribution reduces to a finite mixture of /spl alpha/-/spl mu/ Distributions when the Fading parameters /spl mu/ and m take positive integer values, so that performance analysis over /spl alpha/- KMS Fading channels can be tackled by leveraging previous (existing) results in the literature for the simpler /spl alpha/-spl mu/ case. As application examples, important performance metrics like the outage probability and average channel capacity are analyzed
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the alpha kappa mu shadowed Fading Distribution statistical characterization and applications
arXiv: Information Theory, 2019Co-Authors: Pablo Ramirezespinosa, Daniel Benevides Da Costa, Jules M Moualeu, Javier F LopezmartinezAbstract:We introduce the {\alpha}-{\kappa}-{\mu} shadowed ({\alpha}-KMS) Fading Distribution as a natural generalization of the versatile {\alpha}-{\kappa}-{\mu} and {\alpha}-{\eta}-{\mu} Distributions. The {\alpha}-KMS Fading Distribution unifies a wide set of Fading Distributions, as it includes the {\alpha}-{\kappa}-{\mu}, {\alpha}- {\eta}-{\mu}, {\alpha}-{\mu}, Weibull, {\kappa}-{\mu} shadowed, Rician shadowed, {\kappa}-{\mu} and {\eta}- {\mu} Distributions as special cases, together with classical models like Rice, Nakagami-m, Hoyt, Rayleigh and one-sided Gaussian. Notably, the {\alpha}-KMS Distribution reduces to a finite mixture of {\alpha}-{\mu} Distributions when the Fading parameters {\mu} and m take positive integer values, so that performance analysis over {\alpha}-KMS Fading channels can be tackled by leveraging previous (existing) results in the literature for the simpler {\alpha}-{\mu} case. As application examples, important performance metrics like the outage probability and average channel capacity are analyzed.
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unified analysis of transmit antenna selection in mimo multirelay networks
IEEE Transactions on Vehicular Technology, 2013Co-Authors: Phee Lep Yeoh, Maged Elkashlan, Nan Yang, Daniel Benevides Da Costa, Trung Q DuongAbstract:We present a unified asymptotic framework for transmit antenna selection in multiple-input multiple-output (MIMO) multirelay networks with Rician, Nakagami-m, Weibull, and generalized-K Fading channels. We apply this framework to derive new closed-form expressions for the outage probability and symbol error rate (SER) of amplify-and-forward (AF) relaying in MIMO multirelay networks with two distinct protocols: 1) transmit antenna selection with receiver maximal-ratio combining (TAS/MRC) and 2) transmit antenna selection with receiver selection combining (TAS/SC). Based on these expressions, the diversity order and the array gain with M-ary phase-shift keying and M-ary quadrature-amplitude modulation are derived. We corroborate that the diversity order only depends on the Fading Distribution and the number of diversity branches, whereas the array gain depends on the Fading Distribution, the modulation format, the number of diversity branches, and the average per-hop signal-to-noise ratios (SNRs). We highlight that the diversity order of TAS/MRC is the same as TAS/SC, regardless of the underlying Fading Distribution. As such, we explicitly characterize the SNR gap between TAS/MRC and TAS/SC as the ratio of their respective array gains. An interesting observation is reached that for equal per-hop SNRs, the SNR gap between the two protocols is independent of the number of relays.
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unified analysis of transmit antenna selection in mimo multirelay networks
IEEE Transactions on Vehicular Technology, 2013Co-Authors: Phee Lep Yeoh, Maged Elkashlan, Nan Yang, Daniel Benevides Da Costa, Trung Q DuongAbstract:We present a unified asymptotic framework for transmit antenna selection in multiple-input multiple-output (MIMO) multirelay networks with Rician, Nakagami-m, Weibull, and generalized-K Fading channels. We apply this framework to derive new closed-form expressions for the outage probability and symbol error rate (SER) of amplify-and-forward (AF) relaying in MIMO multirelay networks with two distinct protocols: 1) transmit antenna selection with receiver maximal-ratio combining (TAS/MRC) and 2) transmit antenna selection with receiver selection combining (TAS/SC). Based on these expressions, the diversity order and the array gain with M-ary phase-shift keying and M-ary quadrature-amplitude modulation are derived. We corroborate that the diversity order only depends on the Fading Distribution and the number of diversity branches, whereas the array gain depends on the Fading Distribution, the modulation format, the number of diversity branches, and the average per-hop signal-to-noise ratios (SNRs). We highlight that the diversity order of TAS/MRC is the same as TAS/SC, regardless of the underlying Fading Distribution. As such, we explicitly characterize the SNR gap between TAS/MRC and TAS/SC as the ratio of their respective array gains. An interesting observation is reached that for equal per-hop SNRs, the SNR gap between the two protocols is independent of the number of relays.
Mohamedslim Alouini - One of the best experts on this subject based on the ideXlab platform.
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on the symmetric α stable Distribution with application to symbol error rate calculations
Personal Indoor and Mobile Radio Communications, 2016Co-Authors: Hamza Soury, Mohamedslim AlouiniAbstract:The probability density function (PDF) of the symmetric α-stable Distribution is investigated using the inverse Fourier transform of its characteristic function. For general values of the stable parameter α, it is shown that the PDF and the cumulative Distribution function of the symmetric stable Distribution can be expressed in terms of the Fox H function as closed-form. As an application, the probability of error of single input single output communication systems using different modulation schemes with an α-stable perturbation is studied. In more details, a generic formula is derived for generalized Fading Distribution, such as the extended generalized-k Distribution. Later, simpler expressions of these error rates are deduced for some selected special cases and compact approximations are derived using asymptotic expansions.
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Symbol Error Rate of MPSK Over EGK Channels Perturbed by a Dominant Additive Laplacian Noise
IEEE Transactions on Communications, 2015Co-Authors: Hamza Soury, Mohamedslim AlouiniAbstract:The Laplacian noise has received much attention during the recent years since it affects many communication systems. We consider in this paper the probability of error of an M-ary phase shift keying (PSK) constellation operating over a generalized Fading channel in presence of a dominant additive Laplacian noise. In this context, the decision regions of the receiver are determined using the maximum likelihood and the minimum distance detectors. Once the decision regions are extracted, the resulting symbol error rate expressions are computed and averaged over an extended generalized-K Fading Distribution. Generic closed form expressions of the conditional and the average probability of error are obtained in terms of the Fox's H function. Simplifications for some special cases of Fading are presented and the resulting formulas end up being often expressed in terms of well known elementary functions. Finally, the mathematical formalism is validated using some selected analytical-based numerical results as well as Monte-Carlo simulation-based results.
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on the performance of hybrid rf and rf fso fixed gain dual hop transmission systems
Saudi International Electronics Communications and Photonics Conference, 2013Co-Authors: Imran Shafique Ansari, Mohamedslim Alouini, Ferkan YilmazAbstract:In this work, we present the performance analysis of a dual-branch transmission system composed of a direct radio frequency (RF) link and a dual-hop relay composed of asymmetric RF and free-space optical (FSO) links and compare it without having a direct RF path to see the effects of diversity on our system. The FSO link accounts for pointing errors and both types of detection techniques (i.e. indirect modulation/direct detection (IM/DD) as well as heterodyne detection). The performance is evaluated under the assumption of selection combining diversity scheme. RF links are modeled by Rayleigh Fading Distribution whereas the FSO link is modeled by a unified Gamma-Gamma Fading Distribution. Specifically, we derive new exact closed-form expressions for the cumulative Distribution function, probability density function, moment generating function, and moments of the end-to-end signal-to-noise ratio of these systems in terms of the Meijer's G function. We then capitalize on these results to offer new exact closed-form expressions for the outage probability, higher-order amount of Fading, average error rate for binary and M-ary modulation schemes, and ergodic capacity, all in terms of Meijer's G functions. All our new analytical results are also verified via computer-based Monte-Carlo simulations.
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a novel unified expression for the capacity and bit error probability of wireless communication systems over generalized Fading channels
IEEE Transactions on Communications, 2012Co-Authors: Ferkan Yilmaz, Mohamedslim AlouiniAbstract:Analysis of the average binary error probabilities (ABEP) and average capacity (AC) of wireless communications systems over generalized Fading channels have been considered separately in past years. This paper introduces a novel moment generating function (MGF)-based unified expression for the ABEP and AC of single and multiple link communications with maximal ratio combining. In addition, this paper proposes the hyper-Fox's H Fading model as a unified Fading Distribution of a majority of the well-known generalized Fading environments. As such, the authors offer a generic unified performance expression that can be easily calculated, and that is applicable to a wide variety of Fading scenarios. The mathematical formulism is illustrated with some selected numerical examples that validate the correctness of the authors' newly derived results.
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a novel unified expression for the capacity and bit error probability of wireless communication systems over generalized Fading channels
arXiv: Information Theory, 2011Co-Authors: Ferkan Yilmaz, Mohamedslim AlouiniAbstract:Analysis of the average binary error probabilities (ABEP) and average capacity (AC) of wireless communications systems over generalized Fading channels have been considered separately in the past. This paper introduces a novel moment generating function (MGF)-based \emph{unified expression} for the ABEP and AC of single and multiple link communication with maximal ratio combining. In addition, this paper proposes the hyper-Fox's H Fading model as a unified Fading Distribution of a majority of the well-known generalized Fading models. As such, we offer a generic unified performance expression that can be easily calculated and that is applicable to a wide variety of Fading scenarios. The mathematical formalism is illustrated with some selected numerical examples that validate the correctness of our newly derived results.
Michael R. Souryal - One of the best experts on this subject based on the ideXlab platform.
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Non-Coherent Amplify-and-Forward Generalized Likelihood Ratio Test Receiver
IEEE Transactions on Wireless Communications, 2010Co-Authors: Michael R. SouryalAbstract:This paper proposes a simple non-coherent amplify-and-forward receiver for the relay channel and evaluates its diversity performance for Rayleigh Fading channels. We use the generalized likelihood ratio test to obtain the decision rule in closed form, independent of the Fading Distribution. The receiver is developed for M-ary orthogonal signals and multiple relays. The only side information required at the destination is the average noise energy at the receiver; no statistical knowledge of the channel gains is needed. We develop closed-form upper and lower bounds on the probability of error of this receiver for the case of binary signaling with a single relay and show that this receiver achieves near full diversity, with the probability of error decreasing with increasing signal-to-noise ratio (SNR) as log2(SNR)/ SNR2 for large SNR. Additional results obtained by simulation demonstrate increasing diversity gain with additional relays.
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non coherent amplify and forward generalized likelihood ratio test receiver
Global Communications Conference, 2008Co-Authors: Michael R. SouryalAbstract:This paper proposes a simple non-coherent amplify- and-forward receiver for the relay channel and evaluates its diversity performance for Rayleigh Fading channels. We use the generalized likelihood ratio test to obtain the decision rule in closed form, independent of the Fading Distribution. The receiver is developed for M-ary orthogonal signals and multiple relays. The only side information required is the average noise energy at the receiver; no statistical knowledge of the channel gains is needed. We develop closed-form upper and lower bounds on the probability of error of this receiver for the case of binary signaling with a single relay and show that this receiver achieves near-full diversity, with the probability of error decreasing with increasing signal-to-noise ratio (SNR) as log2 (SNR) /SNR2 for large SNR. Additional results obtained by simulation demonstrate increasing diversity gain with additional relays.
Stefano Rini - One of the best experts on this subject based on the ideXlab platform.
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on capacity of the writing onto fast Fading dirt channel
IEEE Transactions on Wireless Communications, 2018Co-Authors: Stefano Rini, Shlomo Shamai ShitzAbstract:The Writing onto Fast Fading Dirt (WFFD) channel is investigated to study the effect of partial channel knowledge on the performance of interference pre-cancellation. The WFFD channel is the Gel’fand-Pinsker channel in which the channel output is the sum of the channel input, white Gaussian noise, and a Fading-times-state term. The Fading-times-state term is obtained as the product of the channel state sequence, known only at the transmitter, and a fast Fading process, known only at the receiver. We consider the case of Gaussian-distributed channel states and derive an approximate characterization of capacity for different classes of Fading Distributions, both continuous and discrete. In particular, we prove that if the Fading Distribution concentrates in a sufficiently small interval, then capacity is approximately equal to the AWGN capacity times the probability of such interval. We also show that there exists a class of Fading Distributions for which having the transmitter treat the Fading-times-state term as additional noise closely approaches capacity.
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on the capacity of the dirty paper channel with fast Fading and discrete channel states
International Symposium on Information Theory, 2016Co-Authors: Stefano Rini, Shlomo ShamaiAbstract:Interference pre-cancellation as in the “writing onto dirty paper” channel crucially depends on the transmitter having exact knowledge of the way in which input and channel state combine to produce the channel output. The presence of even a small amount of uncertainty in such knowledge, gravely hampers the ability of the encoder to pre-code its transmissions against the channel state. This is particularly disappointing as it implies that interference pre-coding in practical systems is effective only when the channel estimates have very high precision, a condition which is generally unattainable in wireless environments. In this paper we show that state decoding, instead of state pre-cancellation, can be approximately optimal for a channel with discrete states when only partial channel knowledge is available. More specifically, we consider a variation of the “writing onto dirty paper” channel in which a discrete-valued state sequence is multiplied by a fast Fading process and derive conditions on the Fading Distribution for which state decoding closely approaches capacity. This channel model is a special case of the Gelf'and-Pinsker channel and our results show an instance of this problem in which state decoding is approximately optimal.
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on capacity of the writing onto fast Fading dirt channel
arXiv: Information Theory, 2016Co-Authors: Stefano Rini, Shlomo ShamaiAbstract:The "Writing onto Fast Fading Dirt" (WFFD) channel is investigated to study the effects of partial channel knowledge on the capacity of the "writing on dirty paper" channel. The WFFD channel is the Gel'fand-Pinsker channel in which the output is obtained as the sum of the input, white Gaussian noise and a Fading-times-state term. The Fading-times-state term is equal to the element-wise product of the channel state sequence, known only at the transmitter, and a fast Fading process, known only at the receiver. We consider the case of Gaussian distributed channel states and derive an approximate characterization of capacity for different classes of Fading Distributions, both continuous and discrete. In particular, we prove that if the Fading Distribution concentrates in a sufficiently small interval, then capacity is approximately equal to the AWGN capacity times the probability of this interval. We also show that there exists a class of Fading Distributions for which having the transmitter treat the Fading-times-state term as additional noise closely approaches capacity. Although a closed-form expression of the capacity of the general WFFD channel remains unknown, our results show that the presence of Fading can severely reduce the usefulness of channel state knowledge at the transmitter.
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on the dirty paper channel with fast Fading dirt
International Symposium on Information Theory, 2015Co-Authors: Stefano Rini, Shlomo ShamaiAbstract:Costa's “writing on dirty paper” result establishes that full state pre-cancellation can be attained in the Gel'fand-Pinsker problem with additive state and additive white Gaussian noise. This result holds under the assumptions that full channel knowledge is available at both the transmitter and the receiver. In this work we consider the scenario in which the state is multiplied by an ergodic Fading process which is not known at the encoder. We study both the case in which the receiver has knowledge of the Fading and the case in which it does not: for both models we derive inner and outer bounds to capacity and determine the distance between the two bounds when possible. For the channel without Fading knowledge at either the transmitter or the receiver, the gap between inner and outer bounds is finite for a class of Fading Distributions which includes a number of canonical Fading models. In the capacity approaching strategy for this class, the transmitter performs Costa's pre-coding against the mean value of the Fading times the state while the receiver treats the remaining signal as noise. For the case in which only the receiver has knowledge of the Fading, we determine a finite gap between inner and outer bounds for two classes of discrete Fading Distribution. The first class of Distributions is the one in which there exists a probability mass larger than one half while the second class is the one in which the Fading is uniformly distributed over values that are exponentially spaced apart. Unfortunately, the capacity in the case of a continuous Fading Distribution remains very hard to characterize.
