Hybrid Precoding for mmWave Massive MIMO Systems With Partially Connected Structure

Li, Nanxi; Wei, Zaixue; Yang, Hongwen; Zhang, Xin; Yang, Dacheng

doi:10.1109/access.2017.2720163

Cited by 103 publications

(87 citation statements)

References 25 publications

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“…The expression (29) is an upper bound on (25) under the power constraint (26). We now show that there is a specific choice of D such that S = DV * P − 1 2 both satisfies the power constraint and achieves the upper bound, and is therefore optimal.…”

Section: Theorem 1 a Pilot Symbol Matrix Which Solves (25)-(26) Is Gmentioning

confidence: 74%

Pilot contamination mitigation with reduced RF chains

Ioushua

Eldar

2017

2017 IEEE 18th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)

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Abstract-Massive multiple-input multiple-output (MIMO) communication is a promising technology for increasing spectral efficiency in wireless networks. Two of the main challenges massive MIMO systems face are degraded channel estimation accuracy due to pilot contamination and increase in computational load and hardware complexity due to the massive amount of antennas. In this paper, we focus on the problem of channel estimation in massive MIMO systems, while addressing these two challenges: We jointly design the pilot sequences to mitigate the effect of pilot contamination and propose an analog combiner which maps the high number of sensors to a low number of RF chains, thus reducing the computational and hardware cost. We consider a statistical model in which the channel covariance obeys a Kronecker structure. In particular, we treat two such cases, corresponding to fully-and partially-separable correlations. We prove that with these models, the analog combiner design can be done independently of the pilot sequences. Given the resulting combiner, we derive a closed-form expression for the optimal pilot sequences in the fully-separable case and suggest a greedy sum of ratio traces maximization (GSRTM) method for designing sub-optimal pilots in the partially-separable scenario. We demonstrate via simulations that our pilot design framework achieves lower mean squared error than the common pilot allocation framework previously considered for pilot contamination mitigation.

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Section: Theorem 1 a Pilot Symbol Matrix Which Solves (25)-(26) Is Gmentioning

confidence: 74%

Pilot contamination mitigation with reduced RF chains

Ioushua

Eldar

2017

2017 IEEE 18th International Workshop on Signal Processing Advances in Wireless Communications (SPAWC)

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“…For singleuser systems, the principle of manifold optimization and particle swarm optimization are respectively considered to develop two algorithms with different complexity in [27]. The authors in [28] discuss the analog precoding design for high and low SNR conditions, respectively. The original multi-stream transmission problem is decomposed into several single-stream transmission problems with per-antenna power constraint.…”

Section: A Related Workmentioning

confidence: 99%

“…Intuitively, the equivalent problem can be regarded as an atypical clustering problem. Specifically, the set of data samples is consisted by the rows of √ M U The clustering problem (28) can be solved based on Kmeans algorithm. The key approach of the K-means algorithm is the iterative refinement of the clustering and the center updating with the thought of greed [42].…”

Section: A Problem Derivation For Ahpmentioning

confidence: 99%

“…With K out outer iterations 5 , the overall complexity can be similarly given by o(K out K iter (KN 2 RF + K 3 )). Remark: The HAC method is not advisable to solve (28). Since the key approach of HAC is merging clusters until the desired number of clusters is obtained, it is of high possibility to merge two large clusters in the last few loops, which makes the clustering result improbable to satisfy the constraint (29).…”

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confidence: 99%

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Clustering Based Hybrid Precoding Design for Multi-User Massive MIMO Systems

Zhang

Gui

Ying³

et al. 2019

IEEE Trans. Veh. Technol.

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Hybrid precoding has been recognized as a promising technology to combat the path loss of millimeter wave signals in massive multiple-input multiple-output (MIMO) systems. However, due to the joint optimization of the digital and analog precoding matrices as well as extra constraints for the analog part, the hybrid precoding design is still a tough issue in current research. In this paper, we adopt the thought of clustering in unsupervised learning and provide design schemes for fullyconnected hybrid precoding (FHP) and adaptively-connected hybrid precoding (AHP) in multi-user massive MIMO systems. For FHP, we propose the hierarchical-agglomerative-clusteringbased (HAC-based) scheme to explore the relevance among RF chains in optimal hybrid procoding design. The similar RF chains are merged into an individual RF chain when insufficient RF chains are equipped at the base station (BS). For AHP, we propose the modified-K-means-based (MKM-based) scheme to explore the relevance among antennas at the BS. The similar antennas are supported by the same RF chain to make full use of the flexible connection in AHP. Particularly, in proposed MKM-based AHP design, the clustering centers are updated by alternatingoptimum-based (AO-based) scheme with a special initialization method, which is capable to individually provide feasible subconnected hybrid precoding (SHP) design. Simulation results highlight the superior spectrum efficiency of proposed HACbased FHP scheme, and the high power efficiency of proposed MKM-based AHP scheme. Moreover, all the proposed schemes are clarified to effectively handle the inter-user interference and outperform the existing work.Index Terms-Millimeter wave, multi-user massive MIMO systems, clustering, hybrid precoding.

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“…This approach is especially important in the millimeter wave band, where hardware complexity is a limiting factor [4][5][6][7][8]. When designing hybrid precoding systems, several challenges need to be addressed [9][10][11]: the design freedom of RF precoders is commonly restricted by hardware limitations, such as discrete angular resolution and constant modulus of the phase-shifting elements, as well as partial connectivity of the phase-shift network to limit insertion loss. An alternative to hybrid architectures, which potentially provides even higher spectral and energy efficiency in certain operating regimes, is to employ cheap low (even single bit) resolution analog to digital (AD)/digital to analog (DA) converters in FD-MIMO transceivers.…”

Section: Introductionmentioning

confidence: 99%

Robust full-dimension MIMO transmission based on limited feedback angular-domain CSIT

Schwarz

2018

J Wireless Com Network

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In this paper, we propose robust multi-user beamforming and precoding techniques for full-dimension MIMO transmission based on limited feedback. We propose to employ an over-complete basis decomposition in the angular domain to approximate the channel matrices as sums of few dominant specular components, facilitating efficient channel state information (CSI) quantization at the users. The selected expansion vectors of such a sparse approximation, parametrized by azimuth and elevation angles, are relatively robust with respect to channel estimation errors as well as channel variations over time. Based on this CSI feedback, we propose incoherent beamforming/precoding methods that make use only of the azimuth and elevation angles as well as the norm of the expansion coefficients and do not rely on coherent multipath interference to eliminate inter-user interference. Our optimization aims at maximizing the signal power or the achievable rate of a user, while limiting the amount of interference leakage caused to other users. To further improve robustness, we account for uncertainty in the angular channel decomposition in the proposed precoder optimization.

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Hybrid Precoding for mmWave Massive MIMO Systems With Partially Connected Structure

Cited by 103 publications

References 25 publications

Pilot contamination mitigation with reduced RF chains

Pilot contamination mitigation with reduced RF chains

Clustering Based Hybrid Precoding Design for Multi-User Massive MIMO Systems

Robust full-dimension MIMO transmission based on limited feedback angular-domain CSIT

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