human: Given a node-centered hypergraph: <hypergraph>, where nodes represent papers and hyperedges represent sets of papers co-cited by a source paper.

Details of the hypergraph:
Center node: "channel estimation for millimeter wave multiuser mimo systems via parafac decomposition"
  Abstract: We consider the problem of uplink channel estimation for millimeter wave (mmWave) systems, where the base station (BS) and mobile stations (MSs) are equipped with large antenna arrays to provide sufficient beamforming gain for outdoor wireless communications. Hybrid analog and digital beamforming structures are employed by both the BS and the MS due to hardware constraints. We propose a layered pilot transmission scheme and a CANDECOMP/PARAFAC (CP) decomposition-based method for joint estimation of the channels from multiple users (i.e. MSs) to the BS. The proposed method exploits the sparse scattering nature of the mmWave channel and the intrinsic multi-dimensional structure of the multiway data collected from multiple modes. The uniqueness of the CP decomposition is studied and sufficient conditions for essential uniqueness are obtained. The conditions shed light on the design of the beamforming matrix, the combining matrix and the pilot sequences, and meanwhile provide general guidelines for choosing system parameters. Our analysis reveals that our proposed method can achieve a substantial training overhead reduction by employing the layered pilot transmission scheme. Simulation results show that the proposed method presents a clear advantage over a compressed sensing-based method in terms of both estimation accuracy and computational complexity.

Connected through hyperedge HE-1 (induced by source paper "beam squint and channel estimation for wideband mmwave massive mimo ofdm systems"):
  with members:
    - "spatial and frequency wideband effects in millimeter wave massive mimo systems"
    - "beamforming codebook compensation for beam squint with channel capacity constraint"
    - "a new view of multi user hybrid massive mimo non orthogonal angle division multiple access"
    - "multi user precoding and channel estimation for hybrid millimeter wave systems"
    - "millimeter wave channel estimation via exploiting joint sparse and low rank structures"
    - "effect of wideband beam squint on codebook design in phased array wireless systems"
    - "channel estimation for hybrid architecture based wideband millimeter wave systems"
    - "low rank tensor decomposition aided channel estimation for millimeter wave mimo ofdm systems"

Connected through hyperedge HE-2 (induced by source paper "closed loop sparse channel estimation for wideband millimeter wave full dimensional mimo systems"):
  with members:
    - "wideband hybrid precoding for next generation backhaul fronthaul based on mmwave fd mimo"
    - "over sampling codebook based hybrid minimum sum mean square error precoding for millimeter wave 3d mimo"
    - "stochastic successive convex optimization for two timescale hybrid precoding in massive mimo"
    - "multi user precoding and channel estimation for hybrid millimeter wave systems"
    - "compressive sensing techniques for next generation wireless communications"
    - "millimeter wave mimo channel estimation using overlapped beam patterns and rate adaptation"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "an overview of signal processing techniques for millimeter wave mimo systems"

Connected through hyperedge HE-3 (induced by source paper "5g positioning and mapping with diffuse multipath"):
  with members:
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "millimeter wave channel modeling and cellular capacity evaluation"

Connected through hyperedge HE-4 (induced by source paper "matrix completion based channel estimation for mmwave communication systems with array inherent impairments"):
  with members:
    - "millimeter wave channel estimation via exploiting joint sparse and low rank structures"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "channel estimation for hybrid architecture based wideband millimeter wave systems"
    - "subspace estimation and decomposition for large millimeter wave mimo systems"
    - "codebook design for millimeter wave channel estimation with hybrid precoding structure"
    - "channel estimation for mmwave massive mimo based access and backhaul in ultra dense network"
    - "joint csit acquisition based on low rank matrix completion for fdd massive mimo systems"
    - "hybrid analog digital channel estimation and beamforming training throughput tradeoff"

Connected through hyperedge HE-5 (induced by source paper "fast beam alignment for millimeter wave communications a sparse encoding and phaseless decoding approach"):
  with members:
    - "efficient beam alignment for mmwave single carrier systems with hybrid mimo transceivers"
    - "millimeter wave channel estimation via exploiting joint sparse and low rank structures"
    - "compressive channel estimation and tracking for large arrays in mm wave picocells"
    - "low rf complexity technologies to enable millimeter wave mimo with large antenna array for 5g wireless communications"
    - "low rank tensor decomposition aided channel estimation for millimeter wave mimo ofdm systems"
    - "spatially common sparsity based adaptive channel estimation and feedback for fdd massive mimo"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "adaptive millimeter wave beam alignment for dual polarized mimo systems"

Connected through hyperedge HE-6 (induced by source paper "millimeter wave channel estimation via exploiting joint sparse and low rank structures"):
  with members:
    - "compressive channel estimation and tracking for large arrays in mm wave picocells"
    - "low rf complexity technologies to enable millimeter wave mimo with large antenna array for 5g wireless communications"
    - "low rank tensor decomposition aided channel estimation for millimeter wave mimo ofdm systems"
    - "frequency selective hybrid precoding for limited feedback millimeter wave systems"
    - "spatially common sparsity based adaptive channel estimation and feedback for fdd massive mimo"
    - "compressed sensing based multi user millimeter wave systems how many measurements are needed"
    - "efficient compressive phase retrieval with constrained sensing vectors"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"

Connected through hyperedge HE-7 (induced by source paper "low rank tensor decomposition aided channel estimation for millimeter wave mimo ofdm systems"):
  with members:
    - "compressive channel estimation and tracking for large arrays in mm wave picocells"
    - "channel estimation for millimeter wave massive mimo with hybrid precoding over frequency selective fading channels"
    - "a comparison of mimo techniques in downlink millimeter wave cellular networks with hybrid beamforming"
    - "delay and backlog analysis for 60 ghz wireless networks"
    - "achievable rate of rician large scale mimo channels with transceiver hardware impairments"
    - "frequency selective hybrid precoding for limited feedback millimeter wave systems"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"
    - "spatially common sparsity based adaptive channel estimation and feedback for fdd massive mimo"

Connected through hyperedge HE-8 (induced by source paper "beamspace channel estimation for millimeter wave massive mimo systems with lens antenna array"):
  with members:
    - "turbo like beamforming based on tabu search algorithm for millimeter wave massive mimo systems"
    - "compressed sensing based multi user millimeter wave systems how many measurements are needed"
    - "hybrid mimo architectures for millimeter wave communications phase shifters or switches"
    - "millimeter wave mimo with lens antenna array a new path division multiplexing paradigm"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "low complexity hybrid precoding in massive multiuser mimo systems"
    - "scaling up mimo opportunities and challenges with very large arrays"

Question: Please tell me which class the center node belongs to. The 40 classes are: cs.NA(Numerical Analysis), cs.MM(Multimedia), cs.LO(Logic in Computer Science), cs.CY(Computers and Society), cs.CR(Cryptography and Security), cs.DC(Distributed, Parallel, and Cluster Computing), cs.HC(Human-Computer Interaction), cs.CE(Computational Engineering, Finance, and Science), cs.NI(Networking and Internet Architecture), cs.CC(Computational Complexity), cs.AI(Artificial Intelligence), cs.MA(Multiagent Systems), cs.GL(General Literature), cs.NE(Neural and Evolutionary Computing), cs.SC(Symbolic Computation), cs.AR(Hardware Architecture), cs.CV(Computer Vision and Pattern Recognition), cs.GR(Graphics), cs.ET(Emerging Technologies), cs.SY(Systems and Control), cs.CG(Computational Geometry), cs.OH(Other Computer Science), cs.PL(Programming Languages), cs.SE(Software Engineering), cs.LG(Machine Learning), cs.SD(Sound), cs.SI(Social and Information Networks), cs.RO(Robotics), cs.IT(Information Theory), cs.PF(Performance), cs.CL(Computation and Language), cs.IR(Information Retrieval), cs.MS(Mathematical Software), cs.FL(Formal Languages and Automata Theory), cs.DS(Data Structures and Algorithms), cs.OS(Operating Systems), cs.GT(Computer Science and Game Theory), cs.DB(Databases), cs.DL(Digital Libraries), cs.DM(Discrete Mathematics). Directly output the class name.

gpt: cs.IT(Information Theory)