Dans le cadre de notre projet de recherche, nous allons nous interesser aux techniques de concept... more Dans le cadre de notre projet de recherche, nous allons nous interesser aux techniques de conception de systemes integres. Nous mettrons l’accent sur des aspects comme la flexibilite, les possibilites de configuration et de reutilisation. Ces objectifs nous amenent a nous placer a un haut niveau d’abstraction. Nous allons appliquer ces methodes a la modelisation et l'implementation de nouvelles fonctions et techniques employees en telecommunications telles que le turbo-codage et la turbo-detection.
In this work, we investigate the spatial diversity gain offered by on-body channels in indoor env... more In this work, we investigate the spatial diversity gain offered by on-body channels in indoor environments. Narrowband on-body channel measurements are conducted in a dual-link topology, to cover various scenarios with different link geometries and body movements. Cooperative dual-link communications with equal-power allocation scheme are evaluated based on the channel measurements. The simulated bit-error-rate (BER) of the cooperative dual-link is compared with the single-link performance. The results highlight the performance of the cooperative scheme for uncorrelated channels with significant fading variance and close pathloss level. In such cases, spatial diversity effectively improves the quality and BER of on-body communications.
This paper proposes a novel joint channel estimation and beamforming approach for multicell wideb... more This paper proposes a novel joint channel estimation and beamforming approach for multicell wideband massive multiple input multiple output (MIMO) systems. With the proposed channel estimation and beamforming approach, we determine the number of cells $N_c$ that can utilize the same time and frequency resource while mitigating the effect of pilot contamination. The proposed approach exploits the multipath characteristics of wideband channels. Specifically, when the channel has a maximum of $L$ multipath taps, \textcolor{red}{it is shown that $N_c\leq L$ cells can estimate the channels of their user equipments (UEs) and perform beamforming while mitigating the effect of pilot contamination.} In a typical long term evolution (LTE) channel environment having delay spread $T_d=4.69\mu$ second and channel bandwidth $B=2.5$MHz, we have found that $L=18$ cells can use this band. In practice, $T_d$ is constant for a particular environment and carrier frequency, and hence $L$ increases as th...
In this paper, we present some theoretical performance evaluation of the crosstalk precancelation... more In this paper, we present some theoretical performance evaluation of the crosstalk precancelation method presented in the work of Louveaux and van der Venn (2006) for DSL systems. This algorithm uses a limited feedback from the different receivers, returning only the (complex) sign of the error on the detected symbols. It updates the precoder iteratively based on this information and on the knowledge of the transmitted symbols. Very little simulation results had been presented. Here we first propose a slightly modified and simplified version of the algorithm which is significantly less complex. We derive approximate performance expressions for this modified version and compare them to simulation results, showing a very good match. It is then shown how these results can be used to set the different parameters of the method.
This paper considers the competitive resource allocation problem in Multiple-Input Multiple-Outpu... more This paper considers the competitive resource allocation problem in Multiple-Input Multiple-Output (MIMO) interfering channels, when users maximize their energy efficiency. Considering each transmitter-receiver pair as a selfish player, conditions on the existence and uniqueness of the Nash equilibrium of the underlying noncooperative game are obtained. A decentralized asynchronous algorithm is proven to converge towards this equilibrium under the same conditions. Two frameworks are considered for the analysis of this game. On the one hand, the game is rephrased as a Quasi-Variational Inequality (QVI). On the other hand, the best response of the players is analyzed in light of the contraction mappings. For this problem, the contraction approach is shown to lead to tighter results than the QVI one. When specializing the obtained results to OFDM networks, the obtained conditions appear to significantly outperform state-of-the-art works, and to lead to much simpler decentralized algori...
Dans un contexte de communications multi-utilisateurs de type DS-CDMA pour liaison descendante ou... more Dans un contexte de communications multi-utilisateurs de type DS-CDMA pour liaison descendante ou multi-porteuses de type OFDM, nous nous concentrons sur l'estimation aveugle du residu de porteuse pour des transmissions de symboles appartenant a des constellations non-circulaires perturbees par un canal selectif en frequence. Nous constatons que le double de ce residu de porteuse est une frequence cyclique du signal recu ce qui nous permet de construire un estimateur base sur la maximisation des cyclocorrelations empiriques. Nous en etudions les performances asymptotiques et en deduisons ainsi le choix de parametres le regissant. Des simulations pratiques viennent confirmer ces choix.
EURASIP Journal on Wireless Communications and Networking
This paper considers a multi-cell relay-aided orthogonal frequency division multiple access (OFDM... more This paper considers a multi-cell relay-aided orthogonal frequency division multiple access (OFDMA) downlink system, in which all stations are coordinated by a central controller for resource allocation (RA). The decode-and-forward (DF) protocol with opportunistic relaying (OR) and high spectrum efficiency (HSE) is applied. The problem of maximizing the weighted sum of per cell min-rate (WSMR) with per-cell total power constraints is formulated, and its per-cell maximum fairness property is proven. An iterative RA algorithm is proposed to optimize mode selection (decision whether the relay should help or not), subcarrier assignment (MSSA) and power allocation (PA) alternatively. Each iteration is composed of the MSSA stage and the PA stage. During the MSSA stage, the original problem is decoupled into mixed integer linear programs (MILPs) with the tentative PA results, which can be solved by typical MILP solvers. To solve the MILPs more efficiently in polynomial time, a randomized rounding-based MSSA (RR-MSSA) algorithm and a direct rounding-based MSSA (DR-MSSA) algorithm are further proposed. During the PA stage, an algorithm based on single condensation and geometric programming (SCGP) PA is designed to optimize PA with the tentative MSSA results. The convergence and the per-cell user fairness of the proposed RA algorithm are proven. Finally, the performance of the RA algorithm and the benefits of using OR and the HSE protocol are illustrated through numerical experiments.
I would like to express my deep appreciation for the scholarship that Tafila Technical University... more I would like to express my deep appreciation for the scholarship that Tafila Technical University/ Jordan has so generously awarded me for my doctoral studies in Electrical Engineering here at Wichita State University. It is a great honor to be considered worthy of such a gift. My earnest intention was to be an excellent candidate and prove your confidence in me was warranted. Special appreciation is due to the Deans' Council of Tafila Technical University especially Dr. S. Al-Jufout, the Dean of Academic Research and Graduate Studies. Special thanks are also due to my dearest Heba for her sincere patience, support, and for accompanying with me in the long, busy days that I needed to complete this work. I like to express my deepest gratitude to my parents, sisters, brothers, and friends for their unwavering encouragement throughout my education. vi ABSTRACT A Multicarrier Communication (MCM) system such as an Orthogonal Frequency Division Multiplexing OFDM or Discrete Multi Tone (DMT) system has been shown to be an effective technique to combat multipath fading in wireless communications. OFDM is a modulation scheme that allows digital data to be efficiently and reliably transmitted over a radio channel, even in multipath environments. OFDM transmits data by using a large number of narrow bandwidth carriers. These carriers are regularly spaced in frequency, forming a block of spectrum. The frequency spacing and time synchronization of the carriers is chosen in such a way that the carriers are orthogonal, meaning that they do not cause interference to each other. In spite of the success and effectiveness of the OFDM systems, it suffers from two well known draw backs: large Peak to Average Power Ratio (PAPR) and high sensitivity to Carrier Frequency Offset (CFO). The presence of the CFO in the received carrier will lose orthogonality among the carriers and because the CFO causes a reduction of desired signal amplitude in the output decision variable and introduces Inter Carrier Interference (ICI). It then brings up an increase of Bit Error Rate (BER). This makes the problem of estimating the CFO an attractive and necessary research problem. In this dissertation blind estimation techniques will be proposed to estimate the offset parameter.
Ikonomou (see Ph.D. Dissertation, UCL, Belgium, June 2002) and Ikonomou and Vandendorpe (see Euro... more Ikonomou (see Ph.D. Dissertation, UCL, Belgium, June 2002) and Ikonomou and Vandendorpe (see European Transactions on Telecommunications (ETT) Journal, vol.10, no.4, p.407-415, July/August 1999) proposed two fractionally spaced (FS) decision feedback equalising (DFE) receivers performing single user detection (SUD) or joint detection (JD) used in non-cyclic prefixed (NCP) multicarrier-CDMA (MC-CDMA) schemes. The objective of this paper is to compare the performance of the above two equalising schemes, against a simpler receiver structure consisting by a single-tap filter bank used in a cyclic prefixed (CP) MC-CDMA scheme. In the context of the latter, two different banks of single-tap filters are presented: one designed to perform classical zero forcing (ZF) detection and one designed for the minimum mean square error (MMSE) criterion. A comparison is finally made in terms of the bit error rate (BER) between NCP MC-CDMA schemes that use equalising receivers and schemes that use the CP extension technique.
2009 3rd Ieee International Workshop on Computational Advances in Multi Sensor Adaptive Processing, Dec 1, 2009
This paper addresses the mean square error (MSE) uplink/downlink duality for the multiple input m... more This paper addresses the mean square error (MSE) uplink/downlink duality for the multiple input multiple output (MIMO) systems where imperfect channel state information (CSI) is available at the base station (BS) and mobile stations (MSs). The channel is modeled by incorporating antenna correlation at the BS. In contrast to the perfect CSI case where instantaneous MSE duality is considered, the average mean square error (AMSE) duality is exploited. To show the application of our AMSE duality we consider the minimum mean square error (MMSE) transceiver design for the downlink multiuser MIMO systems. Our objective is to minimize the sum MSE constrained with a total BS power and provide robustness against channel uncertainties. In the uplink channel, the power allocation part of this problem is formulated as a geometric program (GP). Based on the solution of GP and the AMSE duality analysis, we propose an iterative algorithm that performs optimization alternatively between the uplink and the downlink channels. The convergence behavior of the proposed algorithm is studied. Computer simulations verify the robustness of the proposed design when compared to the non-robust/naive design.
In this paper, we propose algorithms to jointly optimize the multiple multiantenna relays which a... more In this paper, we propose algorithms to jointly optimize the multiple multiantenna relays which assist multipoint-tomultipoint communications in wireless networks. Assuming that the knowledge of the second order statistics of the channels such as covariance matrices are available, the multiple-input-multipleoutput (MIMO) relays are designed using two different methods: 1) minimize the sum of the powers of the relays while fulfilling the signal-to-interference-plus-noise ratio (SINR) requirements for all destinations and 2) maximize the minimum of the SINRs of all destinations satisfying the transmit power constraint of each MIMO relay. Furthermore, considering the fact that the covariance matrices of the channels between the MIMO relays and destinations are subject to uncertainty due to feedback and quantization errors, the robust versions of the aforementioned methods based on worst-case concept are proposed. It is shown that the proposed nonrobust as well as robust designs are nonconvex optimization problems but they can be solved accurately and efficiently using the standard semidefinite relaxation and randomization techniques. Computer simulations verify the improved performance of the robust designs over nonrobust methods. Index Terms-Channel state information, channel uncertainty and convex optimization, robust MIMO relays, worst-case performance optimization. I. INTRODUCTION T HE application of relays for cooperative communications has received a lot of interest in recent years [1], [2]. It is well known that the channel impairments such as shadowing, multipath fading, distance-dependent path losses and interference, often degrade the link-quality between the source and destination in a wireless network. If the link-quality degrades severely, relays can be employed between the source and destination nodes for assisting the data transmission [1], [2]. In the literature, various types of cooperative communications such as amplify-and-forward (AF), decode-and-forward [2], coded-cooperation [3], and compress-and-forward [4] have been pre-Manuscript
Wireless Personal Communications 2: 145-165, 1995. @ 1995 Kluwer Academic Publishers. Printed in ... more Wireless Personal Communications 2: 145-165, 1995. @ 1995 Kluwer Academic Publishers. Printed in the Netherlands. ... Performance Analysis of Linear MIMO Equalizers for ... Multitone DS/SS Systems in Multipath Channels* ... L. VANDENDORPE** and O. VAN ...
21St European Signal Processing Conference, Sep 1, 2013
This paper presents the Nash equilibrium problem for a multipoint-to-multipoint network whose nod... more This paper presents the Nash equilibrium problem for a multipoint-to-multipoint network whose nodes aim at maximizing their energy efficiency. The original game is reformulated as a max-rate generalized Nash equilibrium problem with coupling among the strategy sets of the players, thus revealing the relationship between the spectral efficiencyand the energy efficiency-based equilibrium points in such a competitive scenario. This general game is then modeled resorting to the quasi-variational inequality framework. This provides us with all the mathematical tools necessary to analyze the features of the equilibrium points and devise novel distributed algorithms.
We consider a state-dependent full-duplex relay channel with the state of the channel non-causall... more We consider a state-dependent full-duplex relay channel with the state of the channel non-causally available at only the relay. In the framework of cooperative wireless networks, some specific terminals can be equipped with cognition capabilities, i.e, the relay in our model. In the discrete memoryless (DM) case, we derive lower and upper bounds on channel capacity. The lower bound is obtained by a coding scheme at the relay that consists in a combination of codeword splitting, Gel'fand-Pinsker binning, and a decode-and-forward scheme. The upper bound is better than that obtained by assuming that the channel state is available at the source and the destination as well. For the Gaussian case, we also derive lower and upper bounds on channel capacity. The lower bound is obtained by a coding scheme which is based on a combination of codeword splitting and Generalized dirty paper coding. The upper bound is also better than that obtained by assuming that the channel state is available at the source, the relay, and the destination. The two bounds meet, and so give the capacity, in some special cases for the degraded Gaussian case.
Dans le cadre de notre projet de recherche, nous allons nous interesser aux techniques de concept... more Dans le cadre de notre projet de recherche, nous allons nous interesser aux techniques de conception de systemes integres. Nous mettrons l’accent sur des aspects comme la flexibilite, les possibilites de configuration et de reutilisation. Ces objectifs nous amenent a nous placer a un haut niveau d’abstraction. Nous allons appliquer ces methodes a la modelisation et l'implementation de nouvelles fonctions et techniques employees en telecommunications telles que le turbo-codage et la turbo-detection.
In this work, we investigate the spatial diversity gain offered by on-body channels in indoor env... more In this work, we investigate the spatial diversity gain offered by on-body channels in indoor environments. Narrowband on-body channel measurements are conducted in a dual-link topology, to cover various scenarios with different link geometries and body movements. Cooperative dual-link communications with equal-power allocation scheme are evaluated based on the channel measurements. The simulated bit-error-rate (BER) of the cooperative dual-link is compared with the single-link performance. The results highlight the performance of the cooperative scheme for uncorrelated channels with significant fading variance and close pathloss level. In such cases, spatial diversity effectively improves the quality and BER of on-body communications.
This paper proposes a novel joint channel estimation and beamforming approach for multicell wideb... more This paper proposes a novel joint channel estimation and beamforming approach for multicell wideband massive multiple input multiple output (MIMO) systems. With the proposed channel estimation and beamforming approach, we determine the number of cells $N_c$ that can utilize the same time and frequency resource while mitigating the effect of pilot contamination. The proposed approach exploits the multipath characteristics of wideband channels. Specifically, when the channel has a maximum of $L$ multipath taps, \textcolor{red}{it is shown that $N_c\leq L$ cells can estimate the channels of their user equipments (UEs) and perform beamforming while mitigating the effect of pilot contamination.} In a typical long term evolution (LTE) channel environment having delay spread $T_d=4.69\mu$ second and channel bandwidth $B=2.5$MHz, we have found that $L=18$ cells can use this band. In practice, $T_d$ is constant for a particular environment and carrier frequency, and hence $L$ increases as th...
In this paper, we present some theoretical performance evaluation of the crosstalk precancelation... more In this paper, we present some theoretical performance evaluation of the crosstalk precancelation method presented in the work of Louveaux and van der Venn (2006) for DSL systems. This algorithm uses a limited feedback from the different receivers, returning only the (complex) sign of the error on the detected symbols. It updates the precoder iteratively based on this information and on the knowledge of the transmitted symbols. Very little simulation results had been presented. Here we first propose a slightly modified and simplified version of the algorithm which is significantly less complex. We derive approximate performance expressions for this modified version and compare them to simulation results, showing a very good match. It is then shown how these results can be used to set the different parameters of the method.
This paper considers the competitive resource allocation problem in Multiple-Input Multiple-Outpu... more This paper considers the competitive resource allocation problem in Multiple-Input Multiple-Output (MIMO) interfering channels, when users maximize their energy efficiency. Considering each transmitter-receiver pair as a selfish player, conditions on the existence and uniqueness of the Nash equilibrium of the underlying noncooperative game are obtained. A decentralized asynchronous algorithm is proven to converge towards this equilibrium under the same conditions. Two frameworks are considered for the analysis of this game. On the one hand, the game is rephrased as a Quasi-Variational Inequality (QVI). On the other hand, the best response of the players is analyzed in light of the contraction mappings. For this problem, the contraction approach is shown to lead to tighter results than the QVI one. When specializing the obtained results to OFDM networks, the obtained conditions appear to significantly outperform state-of-the-art works, and to lead to much simpler decentralized algori...
Dans un contexte de communications multi-utilisateurs de type DS-CDMA pour liaison descendante ou... more Dans un contexte de communications multi-utilisateurs de type DS-CDMA pour liaison descendante ou multi-porteuses de type OFDM, nous nous concentrons sur l'estimation aveugle du residu de porteuse pour des transmissions de symboles appartenant a des constellations non-circulaires perturbees par un canal selectif en frequence. Nous constatons que le double de ce residu de porteuse est une frequence cyclique du signal recu ce qui nous permet de construire un estimateur base sur la maximisation des cyclocorrelations empiriques. Nous en etudions les performances asymptotiques et en deduisons ainsi le choix de parametres le regissant. Des simulations pratiques viennent confirmer ces choix.
EURASIP Journal on Wireless Communications and Networking
This paper considers a multi-cell relay-aided orthogonal frequency division multiple access (OFDM... more This paper considers a multi-cell relay-aided orthogonal frequency division multiple access (OFDMA) downlink system, in which all stations are coordinated by a central controller for resource allocation (RA). The decode-and-forward (DF) protocol with opportunistic relaying (OR) and high spectrum efficiency (HSE) is applied. The problem of maximizing the weighted sum of per cell min-rate (WSMR) with per-cell total power constraints is formulated, and its per-cell maximum fairness property is proven. An iterative RA algorithm is proposed to optimize mode selection (decision whether the relay should help or not), subcarrier assignment (MSSA) and power allocation (PA) alternatively. Each iteration is composed of the MSSA stage and the PA stage. During the MSSA stage, the original problem is decoupled into mixed integer linear programs (MILPs) with the tentative PA results, which can be solved by typical MILP solvers. To solve the MILPs more efficiently in polynomial time, a randomized rounding-based MSSA (RR-MSSA) algorithm and a direct rounding-based MSSA (DR-MSSA) algorithm are further proposed. During the PA stage, an algorithm based on single condensation and geometric programming (SCGP) PA is designed to optimize PA with the tentative MSSA results. The convergence and the per-cell user fairness of the proposed RA algorithm are proven. Finally, the performance of the RA algorithm and the benefits of using OR and the HSE protocol are illustrated through numerical experiments.
I would like to express my deep appreciation for the scholarship that Tafila Technical University... more I would like to express my deep appreciation for the scholarship that Tafila Technical University/ Jordan has so generously awarded me for my doctoral studies in Electrical Engineering here at Wichita State University. It is a great honor to be considered worthy of such a gift. My earnest intention was to be an excellent candidate and prove your confidence in me was warranted. Special appreciation is due to the Deans' Council of Tafila Technical University especially Dr. S. Al-Jufout, the Dean of Academic Research and Graduate Studies. Special thanks are also due to my dearest Heba for her sincere patience, support, and for accompanying with me in the long, busy days that I needed to complete this work. I like to express my deepest gratitude to my parents, sisters, brothers, and friends for their unwavering encouragement throughout my education. vi ABSTRACT A Multicarrier Communication (MCM) system such as an Orthogonal Frequency Division Multiplexing OFDM or Discrete Multi Tone (DMT) system has been shown to be an effective technique to combat multipath fading in wireless communications. OFDM is a modulation scheme that allows digital data to be efficiently and reliably transmitted over a radio channel, even in multipath environments. OFDM transmits data by using a large number of narrow bandwidth carriers. These carriers are regularly spaced in frequency, forming a block of spectrum. The frequency spacing and time synchronization of the carriers is chosen in such a way that the carriers are orthogonal, meaning that they do not cause interference to each other. In spite of the success and effectiveness of the OFDM systems, it suffers from two well known draw backs: large Peak to Average Power Ratio (PAPR) and high sensitivity to Carrier Frequency Offset (CFO). The presence of the CFO in the received carrier will lose orthogonality among the carriers and because the CFO causes a reduction of desired signal amplitude in the output decision variable and introduces Inter Carrier Interference (ICI). It then brings up an increase of Bit Error Rate (BER). This makes the problem of estimating the CFO an attractive and necessary research problem. In this dissertation blind estimation techniques will be proposed to estimate the offset parameter.
Ikonomou (see Ph.D. Dissertation, UCL, Belgium, June 2002) and Ikonomou and Vandendorpe (see Euro... more Ikonomou (see Ph.D. Dissertation, UCL, Belgium, June 2002) and Ikonomou and Vandendorpe (see European Transactions on Telecommunications (ETT) Journal, vol.10, no.4, p.407-415, July/August 1999) proposed two fractionally spaced (FS) decision feedback equalising (DFE) receivers performing single user detection (SUD) or joint detection (JD) used in non-cyclic prefixed (NCP) multicarrier-CDMA (MC-CDMA) schemes. The objective of this paper is to compare the performance of the above two equalising schemes, against a simpler receiver structure consisting by a single-tap filter bank used in a cyclic prefixed (CP) MC-CDMA scheme. In the context of the latter, two different banks of single-tap filters are presented: one designed to perform classical zero forcing (ZF) detection and one designed for the minimum mean square error (MMSE) criterion. A comparison is finally made in terms of the bit error rate (BER) between NCP MC-CDMA schemes that use equalising receivers and schemes that use the CP extension technique.
2009 3rd Ieee International Workshop on Computational Advances in Multi Sensor Adaptive Processing, Dec 1, 2009
This paper addresses the mean square error (MSE) uplink/downlink duality for the multiple input m... more This paper addresses the mean square error (MSE) uplink/downlink duality for the multiple input multiple output (MIMO) systems where imperfect channel state information (CSI) is available at the base station (BS) and mobile stations (MSs). The channel is modeled by incorporating antenna correlation at the BS. In contrast to the perfect CSI case where instantaneous MSE duality is considered, the average mean square error (AMSE) duality is exploited. To show the application of our AMSE duality we consider the minimum mean square error (MMSE) transceiver design for the downlink multiuser MIMO systems. Our objective is to minimize the sum MSE constrained with a total BS power and provide robustness against channel uncertainties. In the uplink channel, the power allocation part of this problem is formulated as a geometric program (GP). Based on the solution of GP and the AMSE duality analysis, we propose an iterative algorithm that performs optimization alternatively between the uplink and the downlink channels. The convergence behavior of the proposed algorithm is studied. Computer simulations verify the robustness of the proposed design when compared to the non-robust/naive design.
In this paper, we propose algorithms to jointly optimize the multiple multiantenna relays which a... more In this paper, we propose algorithms to jointly optimize the multiple multiantenna relays which assist multipoint-tomultipoint communications in wireless networks. Assuming that the knowledge of the second order statistics of the channels such as covariance matrices are available, the multiple-input-multipleoutput (MIMO) relays are designed using two different methods: 1) minimize the sum of the powers of the relays while fulfilling the signal-to-interference-plus-noise ratio (SINR) requirements for all destinations and 2) maximize the minimum of the SINRs of all destinations satisfying the transmit power constraint of each MIMO relay. Furthermore, considering the fact that the covariance matrices of the channels between the MIMO relays and destinations are subject to uncertainty due to feedback and quantization errors, the robust versions of the aforementioned methods based on worst-case concept are proposed. It is shown that the proposed nonrobust as well as robust designs are nonconvex optimization problems but they can be solved accurately and efficiently using the standard semidefinite relaxation and randomization techniques. Computer simulations verify the improved performance of the robust designs over nonrobust methods. Index Terms-Channel state information, channel uncertainty and convex optimization, robust MIMO relays, worst-case performance optimization. I. INTRODUCTION T HE application of relays for cooperative communications has received a lot of interest in recent years [1], [2]. It is well known that the channel impairments such as shadowing, multipath fading, distance-dependent path losses and interference, often degrade the link-quality between the source and destination in a wireless network. If the link-quality degrades severely, relays can be employed between the source and destination nodes for assisting the data transmission [1], [2]. In the literature, various types of cooperative communications such as amplify-and-forward (AF), decode-and-forward [2], coded-cooperation [3], and compress-and-forward [4] have been pre-Manuscript
Wireless Personal Communications 2: 145-165, 1995. @ 1995 Kluwer Academic Publishers. Printed in ... more Wireless Personal Communications 2: 145-165, 1995. @ 1995 Kluwer Academic Publishers. Printed in the Netherlands. ... Performance Analysis of Linear MIMO Equalizers for ... Multitone DS/SS Systems in Multipath Channels* ... L. VANDENDORPE** and O. VAN ...
21St European Signal Processing Conference, Sep 1, 2013
This paper presents the Nash equilibrium problem for a multipoint-to-multipoint network whose nod... more This paper presents the Nash equilibrium problem for a multipoint-to-multipoint network whose nodes aim at maximizing their energy efficiency. The original game is reformulated as a max-rate generalized Nash equilibrium problem with coupling among the strategy sets of the players, thus revealing the relationship between the spectral efficiencyand the energy efficiency-based equilibrium points in such a competitive scenario. This general game is then modeled resorting to the quasi-variational inequality framework. This provides us with all the mathematical tools necessary to analyze the features of the equilibrium points and devise novel distributed algorithms.
We consider a state-dependent full-duplex relay channel with the state of the channel non-causall... more We consider a state-dependent full-duplex relay channel with the state of the channel non-causally available at only the relay. In the framework of cooperative wireless networks, some specific terminals can be equipped with cognition capabilities, i.e, the relay in our model. In the discrete memoryless (DM) case, we derive lower and upper bounds on channel capacity. The lower bound is obtained by a coding scheme at the relay that consists in a combination of codeword splitting, Gel'fand-Pinsker binning, and a decode-and-forward scheme. The upper bound is better than that obtained by assuming that the channel state is available at the source and the destination as well. For the Gaussian case, we also derive lower and upper bounds on channel capacity. The lower bound is obtained by a coding scheme which is based on a combination of codeword splitting and Generalized dirty paper coding. The upper bound is also better than that obtained by assuming that the channel state is available at the source, the relay, and the destination. The two bounds meet, and so give the capacity, in some special cases for the degraded Gaussian case.
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Papers by Luc Vandendorpe