Conversion from Uplink to Downlink Spatio-Temporal Correlation with Cubic Splines

Jordan, Markus; Dimofte, Andrei; Gong, Xitao; Ascheid, Gerd

doi:10.1109/vetecs.2009.5073462

Cited by 25 publications

(13 citation statements)

References 10 publications

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“…In order to reduce the overhead in searching for AOD and/or AOA, one can exploit congruence among different frequency bands. [34], [35] used spatial covariance matrix and statistical reciprocity to perform beamforming. However, frequency separation in these works is small.…”

Section: Introductionmentioning

confidence: 99%

Hybrid Precoding Using Out-of-Band Spatial Information for Multi-User Multi-RF-Chain Millimeter Wave Systems

Zhang

Lu³

et al. 2020

IEEE Access

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With a tremendous amount of underutilized bandwidth, millimeter wave (mmWave) communication is a promising solution to meet the increasing data-rate demands. To deal with high pathloss in mmWave frequency band, efficient large antenna arrays become crucial to provide necessary beamforming and spatial multiplexing gains. Hybrid analog/digital beamforming has been an encouraging technique in order to reduce the complexity and power consumption of large antenna arrays. In this paper, we propose a low-complexity two-stage hybrid analog/digital precoding and combining scheme for downlink multiuser multi-RF-chain mmWave systems using out-of-band spatial information to minimize the mean-squared error (MMSE) in receiving data streams. Particularly, according to sparse spatial characteristics of the mmWave channel, we utilize more efficient Grassmannian codebooks as the training codebooks to generalize a strategy of utilizing sub-6GHz spatial information for constructing multiuser mmWave communication links. The multiuser analog beamforming problem is then formulated as a weighted sparse signal recovery problem with the weights obtained from sub-6GHz spatial information. In addition, the digital precoding and combining scheme is derived using an efficient MMSE scheme for multi precoders at transmitters and combiners at receivers. Numerical results show the obvious advantages of the proposed multiuser hybrid analog/digital precoding/combining design for various practical scenarios. INDEX TERMS Hybrid precoding, millimeter wave communications, minimum mean squared-error (MMSE), out-of-band information.

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Section: Introductionmentioning

confidence: 99%

Hybrid Precoding Using Out-of-Band Spatial Information for Multi-User Multi-RF-Chain Millimeter Wave Systems

Zhang

Lu³

et al. 2020

IEEE Access

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“…Related state-of-the-art techniques for UL to DL covariance matrix conversion in FDD systems have been considered in [11][12][13][14]. The main limitation of [10] and of the related works [11][12][13] is that they are based on simple channel models that do not meet the requirements of modern 4G and 5G system designs. More precisely, the approaches in [11][12][13] seem hard to generalize to arrays with arbitrary geometries and non-isotropic antennas.…”

Section: Introductionmentioning

confidence: 99%

“…More precisely, the approaches in [11][12][13] seem hard to generalize to arrays with arbitrary geometries and non-isotropic antennas. Furthermore, [10][11][12][13] do not consider propagation effects of 3D environments and, most importantly, dual-polarized antenna arrays. In contrast, the technique proposed in [14] is able to cope with these design requirements.…”

Section: Introductionmentioning

confidence: 99%

Downlink Channel Spatial Covariance Estimation in Realistic FDD Massive Mimo Systems

Miretti

Cavalcante

Stańczak

2018

2018 IEEE Global Conference on Signal and Information Processing (GlobalSIP)

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The knowledge of the downlink (DL) channel spatial covariance matrix at the BS is of fundamental importance for large-scale array systems operating in frequency division duplexing (FDD) mode. In particular, this knowledge plays a key role in the DL channel state information (CSI) acquisition. In the massive MIMO regime, traditional schemes based on DL pilots are severely limited by the covariance feedback and the DL training overhead. To overcome this problem, many authors have proposed to obtain an estimate of the DL spatial covariance based on uplink (UL) measurements. However, many of these approaches rely on simple channel models, and they are difficult to extend to more complex models that take into account important effects of propagation in 3D environments and of dual-polarized antenna arrays. In this study we propose a novel technique that takes into account the aforementioned effects, in compliance with the requirements of modern 4G and 5G system designs. Numerical simulations show the effectiveness of our approach.

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“…without requiring continuous covariance feedback. An approach to solve this problem was suggested in [8], based on resampling the covariance for a different wavelength using cubic splines; however this method is only applicable to uniform linear arrays (ULA). Conversely, the scheme proposed in this article is based on a dictionary of pairs of known uplink/downlink covariance matrices.…”

Section: Introductionmentioning

confidence: 99%

“…• unlike [8], no assumptions on the array geometry are required, and it is not required that the same set of BTS antennas are used for the uplink and downlink transmission;…”

Section: Introductionmentioning

confidence: 99%

Channel Covariance Estimation in Massive MIMO Frequency Division Duplex Systems

Decurninge

Guillaud

Slock

2015

2015 IEEE Globecom Workshops (GC Wkshps)

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Abstract-Channel covariance is emerging as a critical ingredient of the acquisition of instantaneous channel state information (CSI) in multi-user Massive MIMO systems operating in frequency division duplex (FDD) mode. In this context, channel reciprocity does not hold, and it is generally expected that covariance information about the downlink channel must be estimated and fed back by the user equipment (UE). As an alternative CSI acquisition technique, we propose to infer the downlink covariance based on the observed uplink covariance. This inference process relies on a dictionary of uplink/downlink covariance matrices, and on interpolation in the corresponding Riemannian space; once the dictionary is known, the estimation does not rely on any form of feedback from the UE. In this article, we present several variants of the interpolation method, and benchmark them through simulations.

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Conversion from Uplink to Downlink Spatio-Temporal Correlation with Cubic Splines

Cited by 25 publications

References 10 publications

Hybrid Precoding Using Out-of-Band Spatial Information for Multi-User Multi-RF-Chain Millimeter Wave Systems

Hybrid Precoding Using Out-of-Band Spatial Information for Multi-User Multi-RF-Chain Millimeter Wave Systems

Downlink Channel Spatial Covariance Estimation in Realistic FDD Massive Mimo Systems

Channel Covariance Estimation in Massive MIMO Frequency Division Duplex Systems

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