Beam-Domain Channel Estimation for FDD Massive MIMO Systems With Optimal Thresholds

Xiong, Xin; Wang, Xiaodong; Gao, Xiqi; You, Xiaohu

doi:10.1109/twc.2017.2701371

Cited by 18 publications

(12 citation statements)

References 33 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The optimal design of A can be obtained by performing the SVD on the CCM [13], but the CCM is difficult to obtain in FDD massive MIMO systems [34]. Benefiting from the structure of steering vectors, the discrete Fourier transform (DFT) matrices are widely adopted in previous works [21], [29], [30]. Specifically, for an ULA with M antennas,…”

Section: Virtual Angular-domain Channel Sparsitymentioning

confidence: 99%

“…Thus, the DL dominant angular set, which is defined as the set that contains the indexes of several largest elements of the virtual angulardomain DL channel, can be estimated from the UL channel with high reliability. Based on the knowledge of dominant angular sets, a user grouping based and a threshold-based DL training methods were proposed in [28] and [29], respectively. However, the method of [28] relies on the assumption of nonoverlapping AoAs for different UE groups, while the method of [29] assumes that some common scatterers are shared by all the UE.…”

Section: Introductionmentioning

confidence: 99%

“…Based on the knowledge of dominant angular sets, a user grouping based and a threshold-based DL training methods were proposed in [28] and [29], respectively. However, the method of [28] relies on the assumption of nonoverlapping AoAs for different UE groups, while the method of [29] assumes that some common scatterers are shared by all the UE. These assumptions can be unrealistic in practical systems since UE are randomly located.…”

Section: Introductionmentioning

confidence: 99%

“…Owing to the sparsity of virtual angular-domain channels, the required training and feedback overheads for our approach increase linearly with the sparsity level rather than the number of antennas at the BS. Compared to the approaches of [28], [29], our proposed scheme can handle arbitrary DL dominant angular sets without any assumption on UE locations. If the CCM is available, our proposed scheme can be easily combined with the knowledge of CCM.…”

Section: Introductionmentioning

confidence: 99%

“…Consequently, pilot and feedback overhead can be further reduced. • We propose a partial orthogonal criterion for multi-user angular-domain pilot design, which removes impractical assumptions on UE locations, such as non-overlapping AoAs [28] and common scatterers [29]. Furthermore, we propose two pilot assignment algorithms which minimize the pilot overhead and the pilot-reuse interference, respectively.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Virtual Angular-Domain Channel Estimation for FDD Based Massive MIMO Systems with Partial Orthogonal Pilot Design

Zhao

Hanzo

et al. 2020

IEEE Trans. Veh. Technol.

View full text Add to dashboard Cite

This paper proposes an virtual angular-domain channel estimation scheme for massive multiple-input multipleoutput systems operating in frequency division duplex (FDD) mode. Different from the conventional scheme where orthogonal pilots are transmitted on different antennas, we propose to transfer the channel estimation problem to the virtual angular domain and utilize the channel sparsity to reduce the training and feedback overhead. An orthogonal matching pursuit with Gram-Schmidt orthogonalization algorithm is proposed to construct the unitary transformation between the spatial domain and the virtual angular domain, which achieves higher sparsity than the existing approaches. Furthermore, we propose to estimate the downlink (DL) dominant angular set, which captures most of the channel power with only a few elements, by utilizing the directional reciprocity of FDD systems, where a calibration algorithm is introduced to handle the different wavelengths of uplink and DL transmissions. Based on the estimated dominant sets, we introduce a partial orthogonal criterion for virtual angular-domain pilot design and further propose two pilot assignment algorithms which minimize pilot overhead and pilotreuse interference, respectively. Theoretical analyses on pilot overhead and the mean square error (MSE) performance are also presented. Simulation results demonstrate that our proposed virtual angular-domain channel estimation scheme provides excellent MSE performance with much reduced pilot overhead and, consequently, enjoys much larger per-user achievable rate in comparison to the conventional schemes.

show abstract