The Experts below are selected from a list of 4398 Experts worldwide ranked by ideXlab platform
Wei Yu - One of the best experts on this subject based on the ideXlab platform.
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Gaussian Z-Interference Channel With a Relay Link: Achievability Region and Asymptotic Sum Capacity
IEEE Transactions on Information Theory, 2012Co-Authors: Lei Zhou, Wei YuAbstract:This paper studies a Gaussian Z-interference channel with a rate-limited digital relay link from one receiver to another. Achievable rate regions are derived based on a combination of a Han-Kobayashi common-private power-splitting technique and either a compress-and-forward relay strategy or a decode-and-forward strategy for interference subtraction at the other end. For the Gaussian Z-interference channel with a digital link from the interference-free receiver to the interfered receiver, the Capacity region is established in the strong interference regime; an achievable rate region is established in the weak interference regime. In the weak interference regime, the decode-and-forward strategy is shown to be asymptotically Sum-Capacity achieving in the high signal-to-noise ratio and high interference-to-noise ratio limit. In this case, each relay bit asymptotically improves the Sum Capacity by one bit. For the Gaussian Z-interference channel with a digital link from the interfered receiver to the interference-free receiver, the Capacity region is established in the strong interference regime; achievable rate regions are established in the moderately strong and weak interference regimes. In addition, the asymptotic Sum Capacity is established in the limit of a large relay link rate. In this case, the Sum Capacity improvement due to the digital link is bounded by half a bit when the interference link is weaker than a certain threshold, but the Sum Capacity improvement becomes unbounded when the interference link is strong.
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gaussian z interference channel with a relay link achievability region and asymptotic Sum Capacity
arXiv: Information Theory, 2010Co-Authors: Lei Zhou, Wei YuAbstract:This paper studies a Gaussian Z-interference channel with a rate-limited digital relay link from one receiver to another. Achievable rate regions are derived based on a combination of Han-Kobayashi common-private information splitting technique and several different relay strategies including compress-and-forward and a partial decode-and-forward strategy, in which the interference is partially decoded then binned and forwarded through the digital link for subtraction at the other end. For the Gaussian Z-interference channel with a digital link from the interference-free receiver to the interfered receiver, the Capacity region is established in the strong interference regime; an achievable rate region is established in the weak interference regime. In the weak interference regime, the partial decode-and-forward strategy is shown to be asymptotically Sum-Capacity achieving in the high signal-to-noise ratio and high interference-to-noise ratio limit. In this case, each relay bit asymptotically improves the Sum Capacity by one bit. For the Gaussian Z-interference channel with a digital link from the interfered receiver to the interference-free receiver, the Capacity region is established in the strong interference regime; achievable rate regions are established in the moderately strong and weak interference regimes. In addition, the asymptotically Sum Capacity is established in the limit of large relay link rate. In this case, the Sum Capacity improvement due to the digital link is bounded by half a bit when the interference link is weaker than certain threshold, but the Sum Capacity improvement becomes unbounded as the interference link becomes stronger.
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Sum Capacity computation for the gaussian vector broadcast channel via dual decomposition
IEEE Transactions on Information Theory, 2006Co-Authors: Wei YuAbstract:A numerical algorithm for the computation of Sum Capacity for the Gaussian vector broadcast channel is proposed. The Sum Capacity computation relies on a duality between the Gaussian vector broadcast channel and the Sum-power constrained Gaussian multiple-access channel. The numerical algorithm is based on a Lagrangian dual decomposition technique and it uses a modified iterative water-filling approach for the Gaussian multiple-access channel. The algorithm converges to the Sum Capacity globally and efficiently
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Sum Capacity of Gaussian vector broadcast channels
IEEE Transactions on Information Theory, 2004Co-Authors: Wei Yu, J M CioffiAbstract:This paper characterizes the Sum Capacity of a class of potentially nondegraded Gaussian vector broadcast channels where a single transmitter with multiple transmit terminals sends independent information to multiple receivers. Coordination is allowed among the transmit terminals, but not among the receive terminals. The Sum Capacity is shown to be a saddle-point of a Gaussian mutual information game, where a signal player chooses a transmit covariance matrix to maximize the mutual information and a fictitious noise player chooses a noise correlation to minimize the mutual information. The Sum Capacity is achieved using a precoding strategy for Gaussian channels with additive side information noncausally known at the transmitter. The optimal precoding structure is shown to correspond to a decision-feedback equalizer that decomposes the broadcast channel into a series of single-user channels with interference pre-subtracted at the transmitter.
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Sum Capacity of a gaussian vector broadcast channel
International Symposium on Information Theory, 2002Co-Authors: Wei Yu, J M CioffiAbstract:The Sum Capacity of a non-degraded Gaussian broadcast channel with multiple antennas at the transmitter and receivers is characterized under a certain condition. The Sum Capacity is achieved using a precoding technique for channels with transmitter side information. The optimal precoder has the structure of a decision-feedback equalizer.
J M Cioffi - One of the best experts on this subject based on the ideXlab platform.
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achieving Sum Capacity of the mimo bc with large transmit array using one shot scalable feedback protocol
Vehicular Technology Conference, 2007Co-Authors: R Agarwal, J M CioffiAbstract:We consider a MIMO broadcast channel (BC) with large M and K, where M is the number of transmit antennas and K is the number of single-antenna users; and propose a scalable feedback protocol that achieves the Sum-Capacity with limited feedback of channel state information (CSI). In our earlier work, we showed that if feedback time slots correspond to channel gains and not to users, the Sum-Capacity M log log K can be achieved with feedback resources growing only as M log K, unlike linearly as M K for conventional schemes. In this work, we show that feedback requirement can further be reduced by half or more, while still achieving the Sum-Capacity. A scalable feedback (SF) protocol using random beamforming (RBF) is proposed, which a) requires finite number of feedback slots upper bounded by a constant, b) is fully distributed, c) needs finite transmission energy during feedback and d) achieves the Sum-Capacity. Numerical results show that feedback load is substantially reduced as compared to conventional schemes, as well as our own previously proposed SF scheme.
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Sum Capacity of Gaussian vector broadcast channels
IEEE Transactions on Information Theory, 2004Co-Authors: Wei Yu, J M CioffiAbstract:This paper characterizes the Sum Capacity of a class of potentially nondegraded Gaussian vector broadcast channels where a single transmitter with multiple transmit terminals sends independent information to multiple receivers. Coordination is allowed among the transmit terminals, but not among the receive terminals. The Sum Capacity is shown to be a saddle-point of a Gaussian mutual information game, where a signal player chooses a transmit covariance matrix to maximize the mutual information and a fictitious noise player chooses a noise correlation to minimize the mutual information. The Sum Capacity is achieved using a precoding strategy for Gaussian channels with additive side information noncausally known at the transmitter. The optimal precoding structure is shown to correspond to a decision-feedback equalizer that decomposes the broadcast channel into a series of single-user channels with interference pre-subtracted at the transmitter.
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Sum Capacity of a gaussian vector broadcast channel
International Symposium on Information Theory, 2002Co-Authors: Wei Yu, J M CioffiAbstract:The Sum Capacity of a non-degraded Gaussian broadcast channel with multiple antennas at the transmitter and receivers is characterized under a certain condition. The Sum Capacity is achieved using a precoding technique for channels with transmitter side information. The optimal precoder has the structure of a decision-feedback equalizer.
Dimitris A Pados - One of the best experts on this subject based on the ideXlab platform.
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optimal orthogonal carriers and Sum sinr Sum Capacity of the multiple access vector channel
IEEE Transactions on Communications, 2012Co-Authors: Dimitris A PadosAbstract:For the general correlated multiple-access vector channel, we derive algebraically the Sum-SINR (signal-to-interference-plus-noise ratio) optimal orthonormal set of carriers for any given set of carrier amplitudes. If, in addition, the correlated multiple-access channel is asSumed Gaussian, the Sum-Capacity optimal orthonormal carrier set design and the jointly Sum-Capacity optimal orthonormal carrier and power assignment, for a given power budget, follow readily.
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Optimal Orthogonal Carriers and Sum-SINR/Sum-Capacity of the Multiple-Access Vector Channel
IEEE Transactions on Communications, 2012Co-Authors: Dimitris A PadosAbstract:For the general correlated multiple-access vector channel, we derive algebraically the Sum-SINR (signal-to-interference-plus-noise ratio) optimal orthonormal set of carriers for any given set of carrier amplitudes. If, in addition, the correlated multiple-access channel is asSumed Gaussian, the Sum-Capacity optimal orthonormal carrier set design and the jointly Sum-Capacity optimal orthonormal carrier and power assignment, for a given power budget, follow readily.
Anthony Ephremides - One of the best experts on this subject based on the ideXlab platform.
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Optimal Sequences and Sum Capacity of Symbol
2020Co-Authors: Sennur Ulukus, Anthony EphremidesAbstract:The optimal signature sequences that maximize the Sum Capacity of a direct sequence code-division multiple-access (CDMA) system are characterized in the general case of symbol delay profile and user power constraints. It is shown that the op- timal Sum Capacity of the symbol asynchronous system equals that of the symbol synchronous system with the same user power con- straints. With the optimal signature sequence set, the maximum Sum Capacity is achieved with white Gaussian input signals. The ex- istence of the optimal signature sequence set is proved by the pro- posal of an explicit construction method for arbitrary user delay profiles and power constraints.
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Optimal sequences and Sum Capacity of symbol asynchronous CDMA systems
IEEE Transactions on Information Theory, 2005Co-Authors: Sennur Ulukus, Anthony EphremidesAbstract:The optimal signature sequences that maximize the Sum Capacity of a direct sequence code-division multiple-access (CDMA) system are characterized in the general case of symbol delay profile and user power constraints. It is shown that the optimal Sum Capacity of the symbol asynchronous system equals that of the symbol synchronous system with the same user power constraints. With the optimal signature sequence set, the maximum Sum Capacity is achieved with white Gaussian input signals. The existence of the optimal signature sequence set is proved by the proposal of an explicit construction method for arbitrary user delay profiles and power constraints.
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GLOBECOM - Optimal sequences that maximize the information theoretic Sum Capacity of symbol asynchronous CDMA systems
IEEE Global Telecommunications Conference 2004. GLOBECOM '04., 2004Co-Authors: Sennur Ulukus, Anthony EphremidesAbstract:The optimal signature sequences that maximize the Sum Capacity of a direct sequence CDMA system are characterized in the general case of symbol delay profile and user power constraints. It is shown that the optimal Sum Capacity of the symbol asynchronous system equals that of the symbol synchronous system with the same user power constraints. With the optimal signature sequence set, the maximum Sum Capacity is achieved with white Gaussian input signals. The existence of the optimal signature sequence set is proved by the proposal of an explicit construction method for arbitrary user delay profiles and power constraints.
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Optimal sequences that maximize the information theoretic Sum Capacity of symbol asynchronous CDMA systems
IEEE Global Telecommunications Conference 2004. GLOBECOM '04., 2004Co-Authors: Sennur Ulukus, Anthony EphremidesAbstract:The optimal signature sequences that maximize the Sum Capacity of a direct sequence CDMA system are characterized in the general case of symbol delay profile and user power constraints. It is shown that the optimal Sum Capacity of the symbol asynchronous system equals that of the symbol synchronous system with the same user power constraints. With the optimal signature sequence set, the maximum Sum Capacity is achieved with white Gaussian input signals. The existence of the optimal signature sequence set is proved by the proposal of an explicit construction method for arbitrary user delay profiles and power constraints.
M. Moeneclaey - One of the best experts on this subject based on the ideXlab platform.
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Sum Capacity of equal-power users in overloaded channels
IEEE Transactions on Communications, 2005Co-Authors: F. Vanhaverbeke, M. MoeneclaeyAbstract:We consider the Sum Capacity of code-division multiple-access (CDMA) signature-sequence sets in overloaded channels that contain an orthogonal subset of dimension N. We introduce a family of signature-sequence sets that consists of a hierarchy of orthogonal subsets (HOS), and show that various signature-sequence sets designed for channel overloading belong to this family. AsSuming an equal average energy (EAE) constraint on the user signals, an expression for the Sum Capacity of the HOS family is derived. We point out that the maximum Sum Capacity over the HOS family is achieved by the multiple-orthogonal (m-O) CDMA sequence sets. The Sum Capacity of m-O is only slightly less than the upper bound imposed by the Gaussian multiple-access channel. Moreover, m-O is superior to a system with N orthogonal sequences and (K-N) pseudonoise (PN) sequences (PN/O), which, in turn, outperforms a system with K PN sequences. Both for PN/O and sequence sets over HOS, there is no additional loss in Sum Capacity if we require the sequences to consist of chips that are binary or quaternary valued.
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On the Sum Capacity of quasi-scalable signature sets
Eighth IEEE International Symposium on Spread Spectrum Techniques and Applications - Programme and Book of Abstracts (IEEE Cat. No.04TH8738), 2004Co-Authors: F. Vanhaverbeke, M. MoeneclaeyAbstract:A strict upper and lower bound are derived for the Sum Capacity of quasi-scalable signature sets. Both bounds are shown to be achievable by an appropriate choice of the signatures. It turns out that the requirement of quasi-scalability results in a very small penalty in terms of Sum Capacity.
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Sum Capacity of binary signatures that minimize the total squared correlation
International Symposium onInformation Theory 2004. ISIT 2004. Proceedings., 2004Co-Authors: F. Vanhaverbeke, M. MoeneclaeyAbstract:We evaluate the Sum Capacity of the binary signatures of [G. N. Karystinos etal., (2001)(2003)] that achieve the lower bound on total squared correlation for binary signatures. Analytical expressions are derived for this Sum Capacity, and it is found that the restriction to binary-valued signatures can have a small but nonnegligible impact on the Sum Capacity.
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Sum Capacity of oversaturated channels based on a hierarchy of orthogonal sets
IEEE International Symposium on Information Theory 2003. Proceedings., 2003Co-Authors: F. Vanhaverbeke, M. MoeneclaeyAbstract:Some oversatured channels that have been presented in the literature can be seen as hierarchies of orthogonal signature sets. We introduce a framework for oversaturated channels based on a hierarchy of orthogonal sets. The Sum Capacity under the equal average input energy constraint is found to depend only on the number of users in every orthogonal layer of the hierarchy. In addition to this, m-OCDMA achieves the highest Sum Capacity among all members of the considered hierarchy for a fixed number of users.
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Sum Capacity of the OCDMA/OCDMA signature sequence set
IEEE Communications Letters, 2002Co-Authors: F. Vanhaverbeke, M. MoeneclaeyAbstract:The Sum Capacity of the OCDMA/OCDMA (O/O) signature sequence set is investigated under the asSumption of equal average-input-energy constraints and perfect synchronization of the users. It is shown that the spectral efficiency of the O/O signature sequence set is only dependent on the SNR and load, but independent of the choice of the orthogonal bases. Moreover, this sequence set is found to be only slightly less efficient in terms of Sum Capacity than the Welch-bound equality sequences.
