Closed-form blind channel estimation in orthogonally coded MIMO-OFDM systems

Sarmadi, Nima; Shahbazpanahi, Shahram

doi:10.1109/icassp.2010.5496018

Cited by 7 publications

(11 citation statements)

References 9 publications

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“…It can be observed from Fig. 1 that in this setup, the RML approach of [8] shows a large bias for all SNR values. Also, the GEV method of [7] shows a larger bias compared to the proposed method.…”

Section: Simulationsmentioning

confidence: 87%

“…It can be observed from Fig. 2 that the RML approach of [8] and the GEV method of [7] are effectively not able to resolve the ambiguity while the proposed method resolves the ambiguities and illustrates good channel estimation performance.…”

Section: Simulationsmentioning

confidence: 88%

“…The full rate OSTBCs of [14,Equation (27) Table I]). The proposed estimator is compared to the generalized eigenvalue (GEV) estimator of [7] and the relaxed maximum likelihood (RML) technique of [8]. Fig.…”

Section: Simulationsmentioning

confidence: 99%

“…Making use of (5) and (7) we rewrite (1) as [2] yi(p) = A(hi)si(p) + vi(p) , i = 0, ..., N0 − 1 (8) where yi(p) Yi(p), vi(p) Vi(p) and [2] A(hi) [a1(hi), . .…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, its computational cost may be considerably high. In the approaches proposed in [7] and [8], finite alphabet constraint of the transmitted symbols is relaxed to convert the original NP-hard channel estimation problem to a simple eigenvalue problem. Nevertheless, the latter approaches generally yield biased channel estimates for the finite sample case and conditions under which unique channel estimates are obtained have not been provided.…”

Section: Introductionmentioning

confidence: 99%

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Closed-form blind channel estimation in orthogonally coded MIMO-OFDM systems: A simple strategy to resolve non-scalar ambiguities

Sarmadi

Pesavento

2011

2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications

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We consider blind channel estimation in multiple-input multipleoutput orthogonal frequency-division multiplexing (MIMO-OFDM) systems with orthogonal space-time block code (OSTBC). We introduce a novel weighted covariance matrix of the received data which exploits all redundancies contained in the code. Based on the orthogonality properties of OSTBCs, we further show that a low-rank subspace mode applies to this matrix. Assuming a delay spread over the wireless channel smaller than the OFDM symbol duration, we prove that the corresponding signal subspace in time-domain collapses to a single principal eigenvector from which the channel taps can be uniquely determined. Unlike to previous methods, which suffer from ambiguities, for example, in the case of rotatable OSTBCs, our weighted covariance approach allows to resolve all non-scalar ambiguities provided that a specific transmitted symbol exhibits a higher power than the remaining symbols.

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Section: Simulationsmentioning

confidence: 87%

Section: Simulationsmentioning

confidence: 88%

Section: Simulationsmentioning

confidence: 99%

“…Making use of (5) and (7) we rewrite (1) as [2] yi(p) = A(hi)si(p) + vi(p) , i = 0, ..., N0 − 1 (8) where yi(p) Yi(p), vi(p) Vi(p) and [2] A(hi) [a1(hi), . .…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Closed-form blind channel estimation in orthogonally coded MIMO-OFDM systems: A simple strategy to resolve non-scalar ambiguities

Sarmadi

Pesavento

2011

2011 IEEE 12th International Workshop on Signal Processing Advances in Wireless Communications

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Subspace-based semiblind channel estimation method for fast fading orthogonally coded MIMO-OFDM systems

Vinogradova

Sarmadi

Pesavento

2011

2011 4th IEEE International Workshop on Computational Advances in Multi-Sensor Adaptive Processing (CAMSAP)

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In this paper, a new semiblind spectrally efficient channel estimation method is presented for fast fading orthogonally coded multiple-input multiple-output orthogonal frequency-division multiplexing (MIMO-OFDM) systems. The proposed method benefits from both the available training symbols inserted in the data frame structure of wireless standards as LTE and WiMAX and the redundancy introduced in the space-time code to enhance channel estimation quality. Our method offers a closed-form solution and performs channel estimation in the time domain in two consecutive steps. First, the subspace containing the true channel vector is estimated from the extended covariance matrix of the received data in a fully blind fashion, and then, the true channel vector is recovered from the obtained subspace using available training symbols. The parsimonious channel characterization that we use decreases the number of parameters required to be estimated. On the one hand, it results in a performance improvement as compared to the frequency domain channel estimation methods by coherent processing over all subcarriers. On the other hand, the bandwidth efficiency is enhanced by training overhead reduction as compared to the pure training-based approaches. Moreover, the proposed method is able to eliminate all nonscalar ambiguities inherent in blind channel estimation techniques in two practically important cases, the systems involving single-antenna receivers and the systems involving rotatable codes.

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New subspace-based blind channel estimation for orthogonally coded MIMO-OFDM systems

Jiang

Lin

Phoong

2014

2014 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)

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Two novel subspace-based blind channel estimation methods for orthogonally coded multiple-input multiple-output (MIMO) orthogonal frequency division multiplexing (OFDM) systems with more than two transmit antennas are proposed in this paper. The proposed methods exploit the null space induced by the orthogonal space-time block codes (OSTBC). They can be applied to systems with one or more receive antennas. Simulation results show that accurate estimates can be obtained.

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Closed-form blind channel estimation in orthogonally coded MIMO-OFDM systems

Cited by 7 publications

References 9 publications

Closed-form blind channel estimation in orthogonally coded MIMO-OFDM systems: A simple strategy to resolve non-scalar ambiguities

Closed-form blind channel estimation in orthogonally coded MIMO-OFDM systems: A simple strategy to resolve non-scalar ambiguities

Subspace-based semiblind channel estimation method for fast fading orthogonally coded MIMO-OFDM systems

New subspace-based blind channel estimation for orthogonally coded MIMO-OFDM systems

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