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: "millimeter wave mimo prototype measurements and experimental results"
  Abstract: Millimeter-wave multi-input multi-output (mm-Wave MIMO) systems are one of the candidate schemes for 5G wireless standardization efforts. In this context, the main contributions of this article are three-fold. 1) We describe parallel sets of measurements at identical transmit-receive location pairs with 2.9, 29 and 61 GHz carrier frequencies in indoor office, shopping mall, and outdoor settings. These measurements provide insights on propagation, blockage and material penetration losses, and the key elements necessary in system design to make mm-Wave systems viable in practice. 2) One of these elements is hybrid beamforming necessary for better link margins by reaping the array gain with large antenna dimensions. From the class of fully-flexible hybrid beamformers, we describe a robust class of directional beamformers towards meeting the high data-rate requirements of mm-Wave systems. 3) Leveraging these design insights, we then describe an experimental prototype system at 28 GHz that realizes high data-rates on both the downlink and uplink and robustly maintains these rates in outdoor and indoor mobility scenarios. In addition to maintaining large signal constellation sizes in spite of radio frequency challenges, this prototype leverages the directional nature of the mm-Wave channel to perform seamless beam switching and handover across mm-Wave base-stations thereby overcoming the path losses in non-line-of-sight links and blockages encountered at mm-Wave frequencies.

Connected through hyperedge HE-1 (induced by source paper "fully partially connected hybrid beamforming architectures for mmwave mu mimo"):
  with members:
    - "hybrid precoding architecture for massive multiuser mimo with dissipation sub connected or fully connected structures"
    - "on the energy efficiency of mimo hybrid beamforming for millimeter wave systems with nonlinear power amplifiers"
    - "hybrid beamforming based on implicit channel state information for millimeter wave links"
    - "fully connected vs sub connected hybrid precoding architectures for mmwave mu mimo"
    - "hybrid analog digital beamforming for massive mimo systems"
    - "frequency domain compressive channel estimation for frequency selective hybrid mmwave mimo systems"
    - "a robust time domain beam alignment scheme for multi user wideband mmwave systems"
    - "an overview of signal processing techniques for millimeter wave mimo systems"

Connected through hyperedge HE-2 (induced by source paper "a distributed multi rf chain hybrid mmwave scheme for small cell systems"):
  with members:
    - "a tutorial on beam management for 3gpp nr at mmwave frequencies"
    - "multi beam noma for hybrid mmwave systems"
    - "multi cell hybrid millimeter wave systems pilot contamination and interference mitigation"
    - "optimal resource allocation for power efficient mc noma with imperfect channel state information"
    - "measurement results for millimeter wave pure los mimo channels"
    - "multi user precoding and channel estimation for hybrid millimeter wave systems"
    - "cell free massive mimo versus small cells"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"

Connected through hyperedge HE-3 (induced by source paper "statistical blockage modeling and robustness of beamforming in millimeter wave systems"):
  with members:
    - "how to dimension 5g network when users are distributed on roads modeled by poisson line process"
    - "small scale local area and transitional millimeter wave propagation for 5g communications"
    - "rapid fading due to human blockage in pedestrian crowds at 5g millimeter wave frequencies"
    - "millimeter wave human blockage at 73 ghz with a simple double knife edge diffraction model and extension for directional antennas"
    - "beamforming tradeoffs for initial ue discovery in millimeter wave mimo systems"
    - "millimeter wave cellular wireless networks potentials and challenges"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "five disruptive technology directions for 5g"

Connected through hyperedge HE-4 (induced by source paper "hand and body blockage measurements with form factor user equipment at 28 ghz"):
  with members:
    - "statistical blockage modeling and robustness of beamforming in millimeter wave systems"
    - "small scale local area and transitional millimeter wave propagation for 5g communications"
    - "rapid fading due to human blockage in pedestrian crowds at 5g millimeter wave frequencies"
    - "millimeter wave human blockage at 73 ghz with a simple double knife edge diffraction model and extension for directional antennas"
    - "directional beamforming for millimeter wave mimo systems"
    - "beamforming tradeoffs for initial ue discovery in millimeter wave mimo systems"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "millimeter wave beamforming for wireless backhaul and access in small cell networks"

Connected through hyperedge HE-5 (induced by source paper "beam codebook design for 5g mmwave terminals"):
  with members:
    - "statistical blockage modeling and robustness of beamforming in millimeter wave systems"
    - "over sampling codebook based hybrid minimum sum mean square error precoding for millimeter wave 3d mimo"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "codebook design for millimeter wave channel estimation with hybrid precoding structure"
    - "beamforming tradeoffs for initial ue discovery in millimeter wave mimo systems"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "what will 5g be"
    - "designing unimodular codes via quadratic optimization"

Connected through hyperedge HE-6 (induced by source paper "evolution of physical layer communications research in the post 5g era"):
  with members:
    - "statistical blockage modeling and robustness of beamforming in millimeter wave systems"
    - "deep learning coordinated beamforming for highly mobile millimeter wave systems"
    - "channel reconstruction based hybrid precoding for millimeter wave multi user mimo systems"
    - "directional beamforming for millimeter wave mimo systems"
    - "beamforming tradeoffs for initial ue discovery in millimeter wave mimo systems"

Connected through hyperedge HE-7 (induced by source paper "antenna placement and performance tradeoffs with hand blockage in millimeter wave systems"):
  with members:
    - "statistical blockage modeling and robustness of beamforming in millimeter wave systems"
    - "5g new radio unveiling the essentials of the next generation wireless access technology"
    - "beamforming tradeoffs for initial ue discovery in millimeter wave mimo systems"
    - "five disruptive technology directions for 5g"

Connected through hyperedge HE-8 (induced by source paper "channel reconstruction based hybrid precoding for millimeter wave multi user mimo systems"):
  with members:
    - "common codebook millimeter wave beam design designing beams for both sounding and communication with uniform planar arrays"
    - "directional beamforming for millimeter wave mimo systems"
    - "investigation of prediction accuracy sensitivity and parameter stability of large scale propagation path loss models for 5g wireless communications"
    - "on the number of rf chains and phase shifters and scheduling design with hybrid analog digital beamforming"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "beamforming tradeoffs for initial ue discovery in millimeter wave mimo systems"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"
    - "channel estimation and hybrid precoding for millimeter wave cellular 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)