Robust transmit zero-forcing filters

Hunger, Raphael; Dietrich, F.A.; Joham, Michael; Utschick, Wolfgang

doi:10.1109/wsa.2004.1407659

Cited by 40 publications

(23 citation statements)

References 20 publications

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“…This MSE-optimal analytical solution constitutes a special case of robust feedforward control filters for dynamic (frequency-selective) systems, previously developed in [26][27][28]. Robust linear precoders that minimize MSE by averaging over CSIT uncertainty have more recently been highlighted for multiple-input single-output (MISO) transmit schemes by [29,30] and for multiuser and MIMO downlinks in [24,31]. Very few solutions have been proposed for robust linear precoder design for more general performance criteria.…”

Section: Assumptions Design Choices and Related Workmentioning

confidence: 99%

Design and measurement-based evaluations of coherent JT CoMP: a study of precoding, user grouping and resource allocation using predicted CSI

Apelfröjd

Sternad

2014

J Wireless Com Network

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Coordinated multipoint (CoMP) transmission provides high theoretic gains in spectral efficiency with coherent joint transmission (JT) to multiple users. However, this requires accurate channel state information at the transmitter (CSIT) and also user groups with spatially compatible users. The aim of this paper is to use measured channels to investigate if significant CoMP gains can still be obtained with channel estimation errors. This turns out to be the case, but requires the combination of several techniques. We here focus on coherent downlink JT CoMP to multiple users within a cluster of cooperating base stations. The use of Kalman predictors is investigated to estimate the complex channel gains at the moment of transmission. It is shown that this can provide sufficient CSIT quality for JT CoMP even for long (>20 ms) system delays at 2.66 GHz at pedestrian velocities or, for lower delays, at 500 MHz, at vehicular velocities. A user grouping and resource allocation scheme that provides appropriate groups for CoMP is also suggested. It provides performance close to that obtained by exhaustive search at very low complexity, low feedback cost and very low backhaul cost. Finally, a robust linear precoder that takes channel uncertainties into account when designing the precoding matrix is considered. We show that, in challenging scenarios, this provides large gains compared with zero-forcing precoding. Evaluations of these design elements are based on measured channels with realistic noise and intercluster interference assumptions. These show that high JT CoMP gains can be expected, on average over large sets of user positions, when the above techniques are combined -especially in severely intracluster interference limited scenarios.

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Section: Assumptions Design Choices and Related Workmentioning

confidence: 99%

Design and measurement-based evaluations of coherent JT CoMP: a study of precoding, user grouping and resource allocation using predicted CSI

Apelfröjd

Sternad

2014

J Wireless Com Network

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“…On the other hand, the stochastic approach optimizes a statistical measure of the system performance assuming that the statistics of the uncertainty is known. A robust nonlinear transmit zero-forcing filter with THP was presented in (Hunger et al, 2004) using a conditional-expectation approach, and has been extended lately in (Shenouda & Davidson, 2007) by relaxing the zero-forcing constraint and using the MMSE criterion. The problem of combined optimization of channel estimation and THP was considered in (Dietrich et al, 2007) and a conditional-expectation approach is adopted to solve the problem.…”

Section: Introductionmentioning

confidence: 99%

Analysis and Design of Tomlinson-Harashima Precoding for Multiuser MIMO Systems

Chen¹,

Huang²,

Zhou³

et al. 2011

MIMO Systems, Theory and Applications

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“…Hence, it is of interest to develop transceiver designs that are robust to errors in CSIT. Robust linear and non-linear transceiver designs for multiuser multi-input single-output (MISO) downlink have been widely studied [10]- [13]. Recently, a robust transceiver design for multiuser MIMO downlink minimizing total BS transmit power under individual user MSE constraints has been reported in [14].…”

Section: Introductionmentioning

confidence: 99%

Robust THP Transceiver Designs for Multiuser MIMO Downlink

Ubaidulla

Chockalingam

2009

2009 IEEE Wireless Communications and Networking Conference

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Abstract-In this paper, we present two robust nonlinear transceiver designs for multiuser multi-input multi-output (MIMO) downlink in the presence of imperfections in the channel state information at the transmitter (CSIT). Both the base station (BS) as well as the users are equipped with multiple antennas. The BS employs Tomlinson-Harashima precoding (THP) for interuser interference pre-cancellation at the transmitter. First, we consider the case where the CSIT error is Gaussian-distributed. In this case, the robust transceiver design seeks to minimize a stochastic function of the sum mean square error (SMSE) under a constraint on the total BS transmit power. We propose an iterative algorithm to solve this problem. Each iteration involves the solution of a second order cone program (SOCP). Next, we consider the case where the CSIT error can be specified by an uncertainty set. In this case, we consider a minimax design for the robust transceiver, where the worst-case SMSE is minimized under a constraint on the total BS transmit power. We show that this design problem can be solved by an iterative algorithm, wherein each iteration involves a pair of semi-definite programs (SDP). Further, we consider an extension of the proposed algorithm to the case with per-antenna power constraints. We illustrate the robustness of the proposed algorithms to imperfections in CSIT through simulations.

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Robust transmit zero-forcing filters

Cited by 40 publications

References 20 publications

Design and measurement-based evaluations of coherent JT CoMP: a study of precoding, user grouping and resource allocation using predicted CSI

Design and measurement-based evaluations of coherent JT CoMP: a study of precoding, user grouping and resource allocation using predicted CSI

Analysis and Design of Tomlinson-Harashima Precoding for Multiuser MIMO Systems

Robust THP Transceiver Designs for Multiuser MIMO Downlink

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