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: "overview of full dimension mimo in lte advanced pro"
  Abstract: Multiple-input multiple-output (MIMO) systems with a large number of base station antennas, often called massive MIMO, have received much attention in academia and industry as a means to improve the spectral efficiency, energy efficiency, and processing complexity of next generation cellular systems. The mobile communication industry has initiated a feasibility study of massive MIMO systems to meet the increasing demand of future wireless systems. Field trials of the proof-of-concept systems have demonstrated the potential gain of the Full-Dimension MIMO (FD-MIMO), an official name for the MIMO enhancement in the 3rd generation partnership project (3GPP). 3GPP initiated standardization activity for the seamless integration of this technology into current 4G LTE systems. In this article, we provide an overview of FD-MIMO systems, with emphasis on the discussion and debate conducted on the standardization process of Release 13. We present key features for FD-MIMO systems, a summary of the major issues for the standardization and practical system design, and performance evaluations for typical FD-MIMO scenarios.

Connected through hyperedge HE-1 (induced by source paper "low rank matrix completion a contemporary survey"):
  with members:
    - "generalized sparse and low rank optimization for ultra dense networks"
    - "neural collaborative filtering"
    - "geometric matrix completion with recurrent multi graph neural networks"
    - "millimeter wave channel estimation via exploiting joint sparse and low rank structures"
    - "no spurious local minima in nonconvex low rank problems a unified geometric analysis"
    - "low rank matrix completion for topological interference management by riemannian pursuit"
    - "nips 2016 tutorial generative adversarial networks"
    - "low rank matrix completion for mobile edge caching in fog ran via riemannian optimization"

Connected through hyperedge HE-2 (induced by source paper "achieving phase coherency and gain stability in active antenna arrays for sub 6 ghz fdd and tdd fd mimo challenges and solutions"):
  with members:
    - "channel reciprocity calibration in tdd hybrid beamforming massive mimo systems"
    - "a framework for over the air reciprocity calibration for tdd massive mimo systems"
    - "toward a realistic assessment of multiple antenna hcns residual additive transceiver hardware impairments and channel aging"
    - "massive mimo performance with imperfect channel reciprocity and channel estimation error"
    - "reciprocity calibration for massive mimo proposal modeling and validation"
    - "uplink performance of time reversal mrc in massive mimo systems subject to phase noise"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"

Connected through hyperedge HE-3 (induced by source paper "low complexity separable beamformers for massive antenna array systems"):
  with members:
    - "energy efficiency of mmwave massive mimo precoding with low resolution dacs"
    - "hybrid beamforming via the kronecker decomposition for the millimeter wave massive mimo systems"
    - "nonlinear adaptive algorithms on rank one tensor models"
    - "massive mimo for next generation wireless systems"

Connected through hyperedge HE-4 (induced by source paper "elevation beamforming with full dimension mimo architectures in 5g systems a tutorial"):
  with members:
    - "asymptotic analysis of rzf over double scattering channels with mmse estimation"
    - "distributed fd mimo cellular evolution for 5g and beyond"
    - "an effective limited feedback scheme for fd mimo based on noncoherent detection and kronecker product codebook"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "3d channel model in 3gpp"
    - "3d massive mimo systems modeling and performance analysis"
    - "a generalized spatial correlation model for 3d mimo channels based on the fourier coefficients of power spectrums"
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"

Connected through hyperedge HE-5 (induced by source paper "limited feedback channel estimation in massive mimo with non uniform directional dictionaries"):
  with members:
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "sparse channel estimation for massive mimo with 1 bit feedback per dimension"
    - "compressed sensing for wireless communications useful tips and tricks"
    - "hybrid mimo architectures for millimeter wave communications phase shifters or switches"
    - "achievable rates of fdd massive mimo systems with spatial channel correlation"
    - "noncoherent trellis coded quantization a practical limited feedback technique for massive mimo systems"
    - "preliminary results on 3d channel modeling from theory to standardization"
    - "scaling up mimo opportunities and challenges with very large arrays"

Connected through hyperedge HE-6 (induced by source paper "spatial covariance estimation for millimeter wave hybrid systems using out of band information"):
  with members:
    - "spatial channel covariance estimation for the hybrid mimo architecture a compressive sensing based approach"
    - "millimeter wave beam selection using out of band spatial information"
    - "millimeter wave vehicular communication to support massive automotive sensing"
    - "channel covariance estimation in massive mimo frequency division duplex systems"
    - "frequency selective hybrid precoding for limited feedback millimeter wave systems"
    - "capacity analysis of one bit quantized mimo systems with transmitter channel state information"
    - "the impact of beamwidth on temporal channel variation in vehicular channels and its implications"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"

Connected through hyperedge HE-7 (induced by source paper "low latency multiuser two way wireless relaying for spectral and energy efficiencies"):
  with members:
    - "joint power allocation and beamforming for energy efficient two way multi relay communications"
    - "energy efficient power control a look at 5g wireless technologies"
    - "a survey of energy efficient techniques for 5g networks and challenges ahead"
    - "passive self interference suppression for full duplex infrastructure nodes"
    - "analysis of oscillator phase noise effects on self interference cancellation in full duplex ofdm radio transceivers"
    - "on design of collaborative beamforming for two way relay networks"
    - "optimal beamforming for two way multi antenna relay channel with analogue network coding"

Connected through hyperedge HE-8 (induced by source paper "channel reciprocity calibration in tdd hybrid beamforming massive mimo systems"):
  with members:
    - "massive mimo performance tdd versus fdd what do measurements say"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "reciprocity calibration for massive mimo proposal modeling and validation"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "scalable synchronization and reciprocity calibration for distributed multiuser mimo"

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)