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420
MIMO minimum total MSE transceiver design with imperfect CSI at both ends
 IEEE Trans. Signal Processing
, 2009
"... Abstract—This paper presents new results on joint linear transceiver design under the minimum total meansquare error (MSE) criterion, with channel mean as well as both transmit and receive correlation information at both ends of a multipleinput multipleoutput (MIMO) link. The joint design is form ..."
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Cited by 31 (3 self)
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Abstract—This paper presents new results on joint linear transceiver design under the minimum total meansquare error (MSE) criterion, with channel mean as well as both transmit and receive correlation information at both ends of a multipleinput multipleoutput (MIMO) link. The joint design is formulated into an optimization problem. The optimum closedform precoder and decoder are derived. Compared to the case with perfect channel state information (CSI), linear filters are added at both ends to balance the suppression of channel noise and the noise from imperfect channel estimation. The impact of channel estimation error as well as channel correlation on system performance is assessed, based on analytical and simulation results. Index Terms—Channel state information (CSI), meansquare error (MSE), multipleinput multipleoutput (MIMO), precoding, spatial multiplexing. I.
Topological interference management through index coding
, 2013
"... While much recent progress on interference networks has come about under the assumption of abundant channel state information at the transmitters (CSIT), a complementary perspective is sought in this work through the study of interference networks with no CSIT except a coarse knowledge of the topolo ..."
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Cited by 30 (14 self)
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While much recent progress on interference networks has come about under the assumption of abundant channel state information at the transmitters (CSIT), a complementary perspective is sought in this work through the study of interference networks with no CSIT except a coarse knowledge of the topology of the network that only allows a distinction between weak and significant channels and no further knowledge of the channel coefficients ’ realizations. Modeled as a degreesoffreedom (DoF) study of a partially connected interference network with no CSIT, the problem is found to have a counterpart in the capacity analysis of wired networks with arbitrary linear network coding at intermediate nodes, under the assumption that the sources are aware only of the end to end topology of the network. The wireless (wired) network DoF (capacity) region, expressed in dimensionless units as a multiple of the DoF (capacity) of a single point to point channel (link), is found to be bounded above by the capacity of an index coding problem where the antidotes graph is the complement of the interference graph of the original network and the bottleneck link capacity is normalized to unity. The problems are shown to be equivalent under linear solutions over the same field. An interference alignment
Optimum power allocation for singleuser MIMO and multiuser MIMOMAC with partial CSI
 IEEE Journal on Selected Areas in Communications
, 2007
"... Abstract — We consider both the singleuser and the multiuser power allocation problems in MIMO systems, where the receiver side has the perfect channel state information (CSI), and the transmitter side has partial CSI, which is in the form of covariance feedback. In a singleuser MIMO system, we co ..."
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Cited by 29 (4 self)
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Abstract — We consider both the singleuser and the multiuser power allocation problems in MIMO systems, where the receiver side has the perfect channel state information (CSI), and the transmitter side has partial CSI, which is in the form of covariance feedback. In a singleuser MIMO system, we consider an iterative algorithm that solves for the eigenvalues of the optimum transmit covariance matrix that maximizes the rate. The algorithm is based on enforcing the KarushKuhnTucker (KKT) optimality conditions of the optimization problem at each iteration. We prove that this algorithm converges to the unique global optimum power allocation when initiated at an arbitrary point. We, then, consider the multiuser generalization of the problem, which is to find the eigenvalues of the optimum transmit covariance matrices of all users that maximize the sum rate of the MIMO multiple access channel (MIMOMAC). For this problem, we propose an algorithm that finds the unique optimum power allocation policies of all users. At a given iteration, the multiuser algorithm updates the power allocation of one user, given the power allocations of the rest of the users, and iterates over all users in a roundrobin fashion. Finally, we make several suggestions that significantly improve the convergence rate of the proposed algorithms. Index Terms — Multiuser MIMO, MIMO multiple access channel, partial CSI, covariance feedback, optimum power allocation.
Efficient feedback methods for mimo channels based on parameterization
 IEEE Trans. on Wireless Commun
, 2007
"... Abstract — In this paper, we propose two efficient lowcomplexity quantization methods for multipleinput multipleoutput (MIMO) systems with finiterate feedback based on proper parameterization of the information to be fed back followed by quantization in the new parameter domain. For a MIMO channel ..."
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Cited by 27 (0 self)
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Abstract — In this paper, we propose two efficient lowcomplexity quantization methods for multipleinput multipleoutput (MIMO) systems with finiterate feedback based on proper parameterization of the information to be fed back followed by quantization in the new parameter domain. For a MIMO channel which has multiple orthonormal vectors as channel spatial information, we exploit the geometrical structure of orthonormality while quantizing the spatial information matrix. The parameterization is of two types: one is in terms of a set of unitnorm vectors with different lengths, and the other is in terms of a minimal number of scalar parameters. These parameters are shown to be independent for the i.i.d. flatfading Rayleigh channel, facilitating efficient quantization. In the first scheme, each of the unitnorm vectors is independently quantized with a finite number of bits using an optimal vector quantization (VQ) technique. Bit allocation is needed between the vectors, and the optimum bit allocation depends on the operating SNR of the system. In the second scheme, the scalar parameters are quantized. In slowly timevarying channels, the scalar parameters are also found to be smoothly changing over time, leading to the development of a simple quantization and feedback method using adaptive delta modulation. The results show that the proposed feedback scheme has a channel tracking feature and achieves a capacity very close to perfect feedback with a reasonable feedback rate. Index Terms — Channel information feedback, channel state information, MIMO systems, multiple antennas, parameterization, quantization, transmit beamforming. I.
How much does transmit correlation affect the sumrate scaling of MIMO Gaussian broadcast channels
 IEEE Trans. Commun
, 2009
"... This paper considers the effect of spatial correlation between transmit antennas on the sumrate capacity of the MIMO broadcast channel (i.e., downlink of a cellular system). Specifically, for a system with a large number of users, we analyze the scaling laws of the sumrate for the dirty paper codi ..."
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Cited by 24 (2 self)
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This paper considers the effect of spatial correlation between transmit antennas on the sumrate capacity of the MIMO broadcast channel (i.e., downlink of a cellular system). Specifically, for a system with a large number of users, we analyze the scaling laws of the sumrate for the dirty paper coding and for different types of beamforming transmission schemes. When the channel is i.i.d., it has been shown that for large the sum rate is equal to where is the number of transmit antennas, is the average signal to noise ratio, and refers to terms that go to zero!# " as. When the channel exhibits some spatial correlation with a covariance $ matrix (nonsingular %' & ($)+*, with), we prove that the sum rate of dirty paper coding. / 0 21 3546($) 7 is. We further show that the sumrate of various beamforming schemes +27 / 7 +8 0 9: achieves 8<; = where depends on the type of beamforming. We can in fact 8 compute for random beamforming proposed in [24] and more generally, for random beamforming with precoding in which beams are premultiplied by a fixed matrix. Simulation results are presented at the end of the paper.
Multiantenna capacity of sparse multipath channels
 IEEE TRANS. INFORM. THEORY
, 2006
"... Existing results on multiinput multioutput (MIMO) channel capacity implicitly assume a rich scattering environment in which the channel power scales quadratically with the number of antennas, resulting in linear capacity scaling with the number of antennas. While this assumption may be justified ..."
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Cited by 23 (6 self)
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Existing results on multiinput multioutput (MIMO) channel capacity implicitly assume a rich scattering environment in which the channel power scales quadratically with the number of antennas, resulting in linear capacity scaling with the number of antennas. While this assumption may be justified in systems with few antennas, it leads to violation of fundamental power conservation principles in the limit of large number of antennas. Furthermore, recent measurement results have shown that physical MIMO channels exhibit a sparse multipath structure, even for relatively few antenna dimensions. Motivated by these observations, we propose a framework for modeling sparse channels and study the coherent capacity of sparse MIMO channels from two perspectives: 1) capacity scaling with the number of antennas, and 2) capacity as a function of transmit SNR for a fixed number of antennas. The statistically independent degrees of freedom (DoF) in sparse channels are less than the number of signalspace dimensions and, as a result, sparse channels afford a fundamental new degree of freedom over which channel capacity can be optimized: the distribution of the DoF’s in the available signalspace dimensions. Our investigation is based on a family of sparse channel configurations whose capacity admits a simple and intuitive closedform approximation and reveals a new tradeoff between the multiplexing gain and the received SNR. We identify an ideal channel
A Deterministic Equivalent for the Analysis of Correlated MIMO Multiple Access Channels
, 2011
"... This article provides novel deterministic equivalents for the Stieltjes transform and the Shannon transform of a class of large dimensional random matrices. These results are used to characterise the ergodic rate region of multiple antenna multiple access channels, when each pointtopoint propagati ..."
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Cited by 22 (8 self)
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This article provides novel deterministic equivalents for the Stieltjes transform and the Shannon transform of a class of large dimensional random matrices. These results are used to characterise the ergodic rate region of multiple antenna multiple access channels, when each pointtopoint propagation channel is modelled according to the Kronecker model. We specifically provide an approximation of all rates achieved within the ergodic rate region and we provide an approximation of the linear precoders that achieve the boundary of the rate region as well as an iterative waterfilling algorithm to obtain these precoders. An original feature of this work is that the proposed deterministic equivalents are proved valid even for strong correlation patterns at both communication sides. The above results are validated by Monte Carlo simulations.
Channel Estimation and Hybrid Precoding for Millimeter Wave Cellular Systems
"... Abstract—Millimeter wave (mmWave) cellular systems will enable gigabitpersecond data rates thanks to the large bandwidth available at mmWave frequencies. To realize sufficient link margin, mmWave systems will employ directional beamforming with large antenna arrays at both the transmitter and rec ..."
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Cited by 19 (3 self)
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Abstract—Millimeter wave (mmWave) cellular systems will enable gigabitpersecond data rates thanks to the large bandwidth available at mmWave frequencies. To realize sufficient link margin, mmWave systems will employ directional beamforming with large antenna arrays at both the transmitter and receiver. Due to the high cost and power consumption of gigasample mixedsignal devices, mmWave precoding will likely be divided among the analog and digital domains. The large number of antennas and the presence of analog beamforming requires the development of mmWavespecific channel estimation and precoding algorithms. This paper develops an adaptive algorithm to estimate the mmWave channel parameters that exploits the poor scattering nature of the channel. To enable the efficient operation of this algorithm, a novel hierarchical multiresolution codebook is designed to construct training beamforming vectors
Interpolation based unitary precoding for spatial multiplexing MIMOOFDM with limited feedback,” in
 Proc. IEEE Globecom’04,
, 2004
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