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: "on the feasibility of beamforming in millimeter wave communication systems with multiple antenna arrays"
  Abstract: The use of the millimeter (mm) wave spectrum for next generation (5G) mobile communication has gained significant attention recently. The small carrier wavelengths at mmwave frequencies enable synthesis of compact antenna arrays, providing beamforming gains that compensate the increased propagation losses. In this work, we investigate the feasibility of employing multiple antenna arrays to obtain diversity/multiplexing gains in mmwave systems, where each of the arrays is capable of beamforming independently. Considering a codebook based beamforming system (e.g., to facilitate limited feedback), we observe that the complexity of \emph{jointly} optimizing the beamforming directions across the multiple arrays is highly prohibitive, even for very reasonable system parameters. To overcome this bottleneck, we develop reduced complexity algorithms for optimizing the choice of beamforming directions, premised on the sparse multipath structure of the mmwave channel. Specifically, we reduce the cardinality of the joint beamforming search space, by restricting attention to a small set of dominant candidate directions. To obtain the set of dominant directions, we develop two complementary approaches: (a) based on computation of a novel spatial power metric; a detailed analysis of this metric shows that, in the limit of large antenna arrays, the selected candidate directions approach the channel's dominant angles of arrival and departure, and (b) precise estimation of the channel's (long-term) dominant angles of arrival, exploiting the correlations of the signals received across the different receiver subarrays. Our methods enable a drastic reduction of the optimization search space (a factor of 100 reduction), while delivering close to optimal performance, thereby indicating the potential feasibility of achieving diversity and multiplexing gains in mmwave systems.

Connected through hyperedge HE-1 (induced by source paper "bit interleaved coded multiple beamforming in millimeter wave massive mimo systems"):
  with members:
    - "diversity analysis of millimeter wave massive mimo systems"
    - "hybrid beamforming for large antenna arrays with phase shifter selection"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "hybrid block diagonalization for massive multiuser mimo systems"

Connected through hyperedge HE-2 (induced by source paper "multiplexing analysis of millimeter wave massive mimo systems"):
  with members:
    - "diversity analysis of millimeter wave massive mimo systems"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "hybrid block diagonalization for massive multiuser mimo systems"
    - "low complexity hybrid precoding in massive multiuser mimo systems"

Connected through hyperedge HE-3 (induced by source paper "diversity analysis of millimeter wave massive mimo systems"):
  with members:
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "hybrid block diagonalization for massive multiuser mimo systems"
    - "low complexity hybrid precoding in massive multiuser mimo systems"

Connected through hyperedge HE-4 (induced by source paper "a comparison of mimo techniques in downlink millimeter wave cellular networks with hybrid beamforming"):
  with members:
    - "local multipath model parameters for generating 5g millimeter wave 3gpp like channel impulse response"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"
    - "dynamic time domain duplexing for self backhauled millimeter wave cellular networks"
    - "capacity analysis of one bit quantized mimo systems with transmitter channel state information"
    - "tractable model for rate in self backhauled millimeter wave cellular networks"
    - "coverage and rate analysis for millimeter wave cellular networks"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "millimeter wave channel modeling and cellular capacity evaluation"

Connected through hyperedge HE-5 (induced by source paper "compressive channel estimation and tracking for large arrays in mm wave picocells"):
  with members:
    - "newtonized orthogonal matching pursuit frequency estimation over the continuum"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "compressive parameter estimation in awgn"
    - "millimeter wave beamforming for wireless backhaul and access in small cell networks"

Connected through hyperedge HE-6 (induced by source paper "a survey of millimeter wave mmwave communications for 5g opportunities and challenges"):
  with members:
    - "hybrid millimeter wave systems a novel paradigm for hetnets"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "coverage and rate analysis for millimeter wave cellular networks"
    - "millimeter wave cellular wireless networks potentials and challenges"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "suboptimal spatial diversity scheme for 60 ghz millimeter wave wlan"
    - "millimeter wave channel modeling and cellular capacity evaluation"
    - "coding the beams improving beamforming training in mmwave communication system"

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)