Feedback-aided selective subspace retransmission for outage-free spatial multiplexing

Hunziker, Thomas; Edlich, Thomas; Dahlhaus, Dirk

doi:10.1109/icics.2007.4449695

Cited by 9 publications

(3 citation statements)

References 13 publications

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“…Given the dimension m of the backup signals, (2) is minimized by the M ×m matrixQ comprising the eigenvectors of H † H associated with the m smallest eigenvalues [2]. This optimal choiceQ leads to the noise power ε = η (Q ), given by…”

Section: Closed-loop Mimo Architecturementioning

confidence: 99%

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On the ergodic performance of a simple closed-loop spatial multiplexing architecture

Hunziker

Edlich

Dahlhaus

2008

2008 International Symposium on Information Theory and Its Applications

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We investigate a closed-loop spatial multiplexing architecture with linear array signal processing, which can be combined with off-the-shelf single-input singleoutput encoders/decoders. Rather than resorting to sophisticated interference cancellation schemes, excessive noise amplification due to ill-conditioned multipleinput multiple-output (MIMO) channels is evaded by retransmission of signal parts in critical subspaces, facilitated by a low-rate feedback channel. This lets the great capacities of MIMO channels be capitalized on with low system complexity, without requiring channel state information at the transmitter end. The closedloop architecture involves a reverse propagation of the noise power, which we study using the theory of Markov chains. Conditions are defined under which stationarity is attained, considering both infinite and finite-rate feedback, and the constrained ergodic capacity of the system is expressed. It turns out that in the case of an (8 × 8) MIMO channel with uncorrelated Rayleigh fading, the constrained capacity comes as close as 4 dB to the unconstrained ergodic MIMO capacity.

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Section: Closed-loop Mimo Architecturementioning

confidence: 99%

“…In a recent paper [2] the authors have proposed a MIMO architecture which evades excessive noise amplification arising from "weak" eigenmodes of a channel by means of an adaptive signal subspace retransmission policy. To show the key idea, let the N ×M matrix H (with N ≥ M ) represent a narrow-band MIMO channel.…”

Section: Introductionmentioning

confidence: 99%

On the ergodic performance of a simple closed-loop spatial multiplexing architecture

Hunziker

Edlich

Dahlhaus

2008

2008 International Symposium on Information Theory and Its Applications

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“…Clearly,theweakpointintheZFdetectoristhenoiseenhancement.Incaseofabadly-conditioned channelmatrix,thesmalleigenvaluesofthechannelmatrixseverelyaffectthesystemperformance. In (Hunziker, Edlich, & Dahlhaus, 2007), the authors suggest a recursive spatial multiplexing (RSM)structure,whichaimstoreduceoravoidnoiseenhancement.Tothatend,RSMincludesa retransmissiondependingontheprojectionofthetransmittedsignalinthepreviousframeontoa subspace.Thedimensionofthesubspaceischosenbasedonthesmalleigenvaluesofthechannel matrix.Policiesareusedinordertoguaranteeacertainlevelofsignal-to-noiseratio(SNR)atthe detector input. In (Shah, Hunziker, Edlich, & Dahlhaus, 2010), RSM has been studied with an independentandidenticallydistributed(i.i.d.…”

Section: Introductionmentioning

confidence: 99%

Recursive Spatial Multiplexing with Adaptive Interference Whitening

Mohamad

Shah

Hunziker

et al. 2017

International Journal of Wireless Networks and Broadband Technologies

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This article describes how recursive spatial multiplexing (RSM) is a closed-loop multiple-input multiple-output (MIMO) structure for achieving the capacity offered by MIMO channels with a low-complexity detector. The authors investigate how to make RSM able to provide a bit-error rate performance, which is robust against different types and levels of interference. The interference arising from simultaneous transmission of information signals is taken into account in the RSM scheme at the receiver using a whitening approach. Here, the covariance matrix is estimated and used subsequently for defining the retransmission subspace identifier to be fed back to the transmitter. The performance of this adaptive RSM scheme is compared with standard linear detection schemes like zero-forcing and minimum mean-squared error receivers. It turns out that the adaptive interference whitening substantially improves the bit-error rate performance. Moreover, adaptive RSM leads to a performance being independent of the correlation coefficient of the interference signals.

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Optimal Recursive Spatial Multiplexing Strategies for Slowly Time-Varying MIMO Channels

Edlich

Hunziker

Shah

et al. 2011

2011 IEEE International Conference on Communications (ICC)

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Feedback-aided selective subspace retransmission for outage-free spatial multiplexing

Cited by 9 publications

References 13 publications

On the ergodic performance of a simple closed-loop spatial multiplexing architecture

On the ergodic performance of a simple closed-loop spatial multiplexing architecture

Recursive Spatial Multiplexing with Adaptive Interference Whitening

Optimal Recursive Spatial Multiplexing Strategies for Slowly Time-Varying MIMO Channels

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