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: "massive mimo combining with switches"
  Abstract: Massive multiple-input multiple-output (MIMO) is expected to play a central role in future wireless systems. The deployment of large antenna arrays at the base station and the mobile users offers multiplexing and beamforming gains that boost system spectral efficiency. Unfortunately, the high cost and power consumption of components like analog-to-digital converters makes assigning an RF chain per antenna and applying typical fully digital precoding/combining solutions difficult. In this letter, a novel architecture for massive MIMO receivers, consisting of arrays of switches and constant (non-tunable) phase shifters, is proposed. This architecture applies a quasi-coherent combining in the RF domain to reduce the number of required RF chains. An algorithm that designs the RF combining for this architecture is developed and analyzed. Results show that the proposed massive MIMO combining model can achieve a comparable performance to the fully digital receiver architecture in single-user and multiuser massive MIMO setups.

Connected through hyperedge HE-1 (induced by source paper "hybrid combining based on constant phase shifters and active inactive switches"):
  with members:
    - "resolution adaptive hybrid mimo architectures for millimeter wave communications"
    - "are mmwave low complexity beamforming structures energy efficient analysis of the downlink mu mimo"
    - "millimeter wave receiver efficiency a comprehensive comparison of beamforming schemes with low resolution adcs"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"
    - "hybrid mimo architectures for millimeter wave communications phase shifters or switches"
    - "massive mimo for next generation wireless systems"
    - "spatially sparse precoding in millimeter wave mimo systems"

Connected through hyperedge HE-2 (induced by source paper "robust hybrid precoding for beam misalignment in millimeter wave communications"):
  with members:
    - "secure hybrid analog and digital receive beamforming schemes for efficient interference reduction"
    - "impact of beam misalignment on hybrid beamforming noma for mmwave communications"
    - "joint power allocation and beamforming for non orthogonal multiple access noma in 5g millimeter wave communications"
    - "alternating minimization for hybrid precoding in multiuser ofdm mmwave systems"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "analysis on 60 ghz wireless communications with beamwidth dependent misalignment"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "stochastic geometry modeling and analysis of multi tier millimeter wave cellular networks"

Connected through hyperedge HE-3 (induced by source paper "unequally sub connected architecture for hybrid beamforming in massive mimo systems"):
  with members:
    - "energy efficient transceiver design for hybrid sub array architecture mimo systems"
    - "cell coverage extension with orthogonal random precoding for massive mimo systems"
    - "hybrid beamforming for large antenna arrays with phase shifter selection"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "low rf complexity technologies to enable millimeter wave mimo with large antenna array for 5g wireless communications"
    - "on the number of rf chains and phase shifters and scheduling design with hybrid analog digital beamforming"
    - "dynamic subarrays for hybrid precoding in wideband mmwave mimo systems"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"

Connected through hyperedge HE-4 (induced by source paper "hybrid beamforming with selection for multiuser massive mimo systems"):
  with members:
    - "stationarity region of mm wave channel based on outdoor microcellular measurements at 28 ghz"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "5g 3gpp like channel models for outdoor urban microcellular and macrocellular environments"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "hybrid beamforming for massive mimo a survey"
    - "analysis of the local quasi stationarity of measured dual polarized mimo channels"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"

Connected through hyperedge HE-5 (induced by source paper "energy efficiency and asymptotic performance evaluation of beamforming structures in doubly massive mimo mmwave systems"):
  with members:
    - "doubly massive mmwave mimo systems using very large antenna arrays at both transmitter and receiver"
    - "multi user massive mimo communication systems based on irregular antenna arrays"
    - "enhancing the estimation of mm wave large array channels by exploiting spatio temporal correlation and sparse scattering"
    - "energy efficiency optimization of 5g radio frequency chain systems"
    - "on clustered statistical mimo millimeter wave channel simulation"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "a survey of energy efficient techniques for 5g networks and challenges ahead"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"

Connected through hyperedge HE-6 (induced by source paper "hybrid beamforming with reduced number of phase shifters for massive mimo systems"):
  with members:
    - "hybrid beamforming for large antenna arrays with phase shifter selection"
    - "massive mimo in real propagation environments do all antennas contribute equally"
    - "downlink training techniques for fdd massive mimo systems open loop and closed loop training with memory"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "scaling up mimo opportunities and challenges with very large arrays"

Connected through hyperedge HE-7 (induced by source paper "noma meets finite resolution analog beamforming in massive mimo and millimeter wave networks"):
  with members:
    - "machine learning inspired energy efficient hybrid precoding for mmwave massive mimo systems"
    - "power domain non orthogonal multiple access noma in 5g systems potentials and challenges"
    - "design of massive mimo noma with limited feedback"
    - "resource management in non orthogonal multiple access networks for 5g and beyond"
    - "on the performance of non orthogonal multiple access in 5g systems with randomly deployed users"

Connected through hyperedge HE-8 (induced by source paper "machine learning inspired energy efficient hybrid precoding for mmwave massive mimo systems"):
  with members:
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"
    - "hybrid mimo architectures for millimeter wave communications phase shifters or switches"
    - "spatially sparse precoding in millimeter wave mimo systems"

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)