The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform
Peter M. Grant - One of the best experts on this subject based on the ideXlab platform.
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Trellis coded spatial modulation
IEEE Transactions on Wireless Communications, 2010Co-Authors: Raed Y. Mesleh, Marco Di Renzo, Harald Haas, Peter M. GrantAbstract:Trellis coded modulation (TCM) is a well known scheme that reduces power requirements without any bandwidth expansion. In TCM, only certain sequences of successive constellation points are allowed (mapping by set partitioning). The novel idea in this paper is to apply the TCM concept to the antenna constellation points of spatial modulation (SM). The aim is to enhance SM performance in correlated channel conditions. SM considers the multiple transmit antennas as additional constellation points and maps a first part of a block of information bits to the transmit antenna indices. Therefore, spatial multiplexing gains are retained and spectral efficiency is boosted. The second part of the block of information bits is mapped to a complex Symbol using conventional digital modulation schemes. At any particular time instant, only one antenna is active. The receiver estimates the Transmitted Symbol and the active antenna index and uses the two estimates to retrieve the original block of data bits. In this paper, TCM partitions the entire set of transmit antennas into sub-sets such that the spacing between antennas within a particular sub-set is maximized. The scheme is called trellis coded spatial modulation (TCSM). Tight analytical performance bounds over correlated fading channels are proposed in this paper. In addition, the performance and complexity of TCSM is compared to the performance of SM, coded V-BLAST (vertical Bell Labs layered space-time) applying near optimum sphere decoder algorithm, and Alamouti scheme combined with TCM. Also, the performance of all schemes with turbo coded modulation is presented. It is shown that under the same spectral efficiency, TCSM exhibits significant performance enhancements in the presence of realistic channel conditions such as Rician fading and spatial correlation (SC). In addition, the complexity of the proposed scheme is shown to be 80% less than the V-BLAST complexity.
John P. Fonseka - One of the best experts on this subject based on the ideXlab platform.
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Nonlinear PSK and combined nonlinear PSK/FSK modulation
IEEE Transactions on Communications, 1995Co-Authors: John P. FonsekaAbstract:Two classes of constant envelope signals called, nonlinear PSK and combined nonlinear PSK/FSK are introduced. Nonlinear PSK signals select a constant phase angle during each interval depending on the state of the signal and the Transmitted Symbol. Combined nonlinear PSK/FSK signals select a linear phase variation during each interval and a discrete phase variation at the end of each interval depending on the current state and the Transmitted Symbol. Both classes of signals achieve the highest constraint length allowed by the number of states. The numerical results presented at preselected numbers of states show that these signals produce significantly high minimum distances. Distances higher than those found in the literature at the same number of states are reported. The spectra of nonlinear PSK signals are almost identical to the spectrum of BPSK signals, while those of combined nonlinear PSK/FSK signals are continuous but similar to that of BPSK signals. >
Raed Y. Mesleh - One of the best experts on this subject based on the ideXlab platform.
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Trellis coded spatial modulation
IEEE Transactions on Wireless Communications, 2010Co-Authors: Raed Y. Mesleh, Marco Di Renzo, Harald Haas, Peter M. GrantAbstract:Trellis coded modulation (TCM) is a well known scheme that reduces power requirements without any bandwidth expansion. In TCM, only certain sequences of successive constellation points are allowed (mapping by set partitioning). The novel idea in this paper is to apply the TCM concept to the antenna constellation points of spatial modulation (SM). The aim is to enhance SM performance in correlated channel conditions. SM considers the multiple transmit antennas as additional constellation points and maps a first part of a block of information bits to the transmit antenna indices. Therefore, spatial multiplexing gains are retained and spectral efficiency is boosted. The second part of the block of information bits is mapped to a complex Symbol using conventional digital modulation schemes. At any particular time instant, only one antenna is active. The receiver estimates the Transmitted Symbol and the active antenna index and uses the two estimates to retrieve the original block of data bits. In this paper, TCM partitions the entire set of transmit antennas into sub-sets such that the spacing between antennas within a particular sub-set is maximized. The scheme is called trellis coded spatial modulation (TCSM). Tight analytical performance bounds over correlated fading channels are proposed in this paper. In addition, the performance and complexity of TCSM is compared to the performance of SM, coded V-BLAST (vertical Bell Labs layered space-time) applying near optimum sphere decoder algorithm, and Alamouti scheme combined with TCM. Also, the performance of all schemes with turbo coded modulation is presented. It is shown that under the same spectral efficiency, TCSM exhibits significant performance enhancements in the presence of realistic channel conditions such as Rician fading and spatial correlation (SC). In addition, the complexity of the proposed scheme is shown to be 80% less than the V-BLAST complexity.
Raymond W. Yeung - One of the best experts on this subject based on the ideXlab platform.
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Cut-Set Bounds for Networks With Zero-Delay Nodes
IEEE Transactions on Information Theory, 2015Co-Authors: Silas L. Fong, Raymond W. YeungAbstract:In a network, a node is said to incur a delay if its encoding of each Transmitted Symbol involves only its received Symbols obtained before the time slot in which the Transmitted Symbol is sent (hence the Transmitted Symbol sent in a time slot cannot depend on the received Symbol obtained in the same time slot). A node is said to incur no delay if its received Symbol obtained in a time slot is available for encoding its Transmitted Symbol sent in the same time slot. Under the classical model, every node in a discrete memoryless network (DMN) incurs a unit delay, and the capacity region of the DMN satisfies the well-known cut-set outer bound. In this paper, we propose a generalized model for the DMN where some nodes may incur no delay. Under our generalized model, we obtain a new cut-set outer bound, which is proved to be tight for some two-node DMN and is shown to subsume an existing cut-set bound for the causal relay network. In addition, we establish under the generalized model another cut-set outer bound on the positive-delay region -- the set of achievable rate tuples under the constraint that every node incurs a delay. We use the cut-set bound on the positive-delay region to show that for some two-node DMN under the generalized model, the positive-delay region is strictly smaller than the capacity region.
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Cut-Set Bounds for Generalized Networks
arXiv: Information Theory, 2013Co-Authors: Silas L. Fong, Raymond W. YeungAbstract:In a network, a node is said to incur a delay if its encoding of each Transmitted Symbol involves only its received Symbols obtained before the time slot in which the Transmitted Symbol is sent (hence the Transmitted Symbol sent in a time slot cannot depend on the received Symbol obtained in the same time slot). A node is said to incur no delay if its received Symbol obtained in a time slot is available for encoding its Transmitted Symbol sent in the same time slot. In the classical discrete memoryless network (DMN), every node incurs a delay. A well-known result for the classical DMN is the cut-set outer bound. In this paper, we generalize the model of the DMN in such a way that some nodes may incur no delay, and we obtain the cut-set bound on the capacity region of the generalized DMN. In addition, we establish the cut-set outer bound on the positive-delay region - the capacity region of the generalized DMN under the constraint that every node incurs a delay. Then, we use the cut-set bound on the positive-delay region to show that in some two-node generalized DMN, the positive-delay region is strictly smaller than the capacity region. Finally, we demonstrate that our cut-set bound on the capacity region subsumes an existing cut-set bound for the causal relay network.
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ISIT - Cut-set bound for generalized networks with positive delay
2012 IEEE International Symposium on Information Theory Proceedings, 2012Co-Authors: Silas L. Fong, Raymond W. YeungAbstract:In a network, a node is said to incur a delay if its encoding of each Transmitted Symbol involves only its received Symbols obtained before the time slot in which the Transmitted Symbol is sent (hence the Transmitted Symbol sent in a time slot cannot depend on the received Symbol obtained in the same time slot). A node is said to incur no delay if its received Symbol obtained in a time slot is available for encoding its Transmitted Symbol sent in the same time slot. In this paper, we investigate the generalized discrete memoryless network (DMN) where some nodes may incur no delay. We call the capacity region of the generalized DMN under the constraint that every node incurs a delay the positive-delay region. We establish the cut-set outer bound on the positive-delay region. In addition, we use our cut-set outer bound to show that in some two-node generalized DMN, the positive-delay region is strictly smaller than the capacity region.
Weihua Zhuang - One of the best experts on this subject based on the ideXlab platform.
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channel precoding with small envelope variations for spl pi 4 qpsk and msk over frequency selective slow fading channels
IEEE Transactions on Vehicular Technology, 2003Co-Authors: Weihua ZhuangAbstract:This paper presents channel precoding schemes to combat interSymbol interference (ISI) over a frequency-selective slow fading channel in wireless communication systems using /spl pi//4 shifted quadrature phase-shift keying or minimum shift keying. Based on the dimension partitioning technique, the precoders predistort the phase of the Transmitted Symbol in the forward link to combat ISI, keeping the Transmitted Symbol amplitude constant. The proposed schemes can ensure the stability of the precoder even in equalizing a nonminimum-phase channel, combat ISI without increasing the complexity of portable unit receivers, and reduce the envelope variations of Transmitted signals such that power-efficient nonlinear amplifiers can be used for the precoded signals without causing a significant undue distortion. Theoretical analysis and simulation results are presented to demonstrate the effectiveness of the proposed channel precoding schemes.
