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: "iterative eigenvalue decomposition and multipath grouping tx rx joint beamformings for millimeter wave communications"
  Abstract: We investigate Tx/Rx joint beamforming in millimeter-wave communications (MMWC). As the multipath components (MPCs) have different steering angles and independent fadings, beamforming aims at achieving array gain and diversity gain in this scenario. A sub-optimal beamforming scheme is proposed to find the antenna weight vectors (AWVs) at Tx/Rx via iterative eigenvalue decomposition (EVD), provided that full channel state information (CSI) is available at both the transmitter and receiver. To make this scheme practically feasible in MMWC, a corresponding training approach is suggested to avoid the channel estimation and iterative EVD computation. As in fast fading scenario, the training approach may be time-consuming due to frequent training; another beamforming scheme, which exploits the quasi-static steering angles in MMWC, is proposed to reduce the overhead and increase the system reliability by multipath grouping (MPG). The scheme first groups the MPCs and then concurrently beamforms toward multiple steering angles of the grouped MPCs, so that both array gain and diversity gain are achieved. Performance comparisons show that, compared with the corresponding state-of-the-art schemes, the iterative EVD scheme with the training approach achieves the same performance with a reduced overhead and complexity, whereas the MPG scheme achieves better performance with approximately equivalent complexity.

Connected through hyperedge HE-1 (induced by source paper "energy efficient transceiver design for hybrid sub array architecture mimo systems"):
  with members:
    - "secure massive mimo systems with limited rf chains"
    - "wireless powered communication opportunities and challenges"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "what will 5g be"
    - "millimeter wave cellular wireless networks potentials and challenges"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "low complexity hybrid precoding in massive multiuser mimo systems"

Connected through hyperedge HE-2 (induced by source paper "millimeter wave mimo channel estimation using overlapped beam patterns and rate adaptation"):
  with members:
    - "fast channel estimation for millimetre wave wireless systems using overlapped beam patterns"
    - "race a rate adaptive channel estimation approach for millimeter wave mimo systems"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "pilot beam sequence design for channel estimation in millimeter wave mimo systems a pomdp framework"
    - "iterative joint beamforming training with constant amplitude phased arrays in millimeter wave communications"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "millimeter wave cellular wireless networks potentials and challenges"
    - "millimeter wave channel modeling and cellular capacity evaluation"

Connected through hyperedge HE-3 (induced by source paper "codebook design for millimeter wave channel estimation with hybrid precoding structure"):
  with members:
    - "fast channel estimation for millimetre wave wireless systems using overlapped beam patterns"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "low complexity hybrid precoding and channel estimation based on hierarchical multi beam search for millimeter wave mimo 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"
    - "pilot reuse for massive mimo transmission over spatially correlated rayleigh fading channels"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "massive mimo for next generation wireless systems"

Connected through hyperedge HE-4 (induced by source paper "hierarchical codebook design for beamforming training in millimeter wave communication"):
  with members:
    - "fast channel estimation for millimetre wave wireless systems using overlapped beam patterns"
    - "frequency selective hybrid precoding for limited feedback millimeter wave systems"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"
    - "compressed sensing based multi user millimeter wave systems how many measurements are needed"
    - "iterative joint beamforming training with constant amplitude phased arrays in millimeter wave communications"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "suboptimal spatial diversity scheme for 60 ghz millimeter wave wlan"

Connected through hyperedge HE-5 (induced by source paper "low complexity hybrid precoding and channel estimation based on hierarchical multi beam search for millimeter wave mimo systems"):
  with members:
    - "iterative joint beamforming training with constant amplitude phased arrays in millimeter wave communications"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "suboptimal spatial diversity scheme for 60 ghz millimeter wave wlan"
    - "millimeter wave beamforming for wireless backhaul and access in small cell networks"

Connected through hyperedge HE-6 (induced by source paper "energy efficient scheduling for mmwave backhauling of small cells in heterogeneous cellular networks"):
  with members:
    - "5g wireless backhaul networks challenges and research advances"
    - "wireless backhaul node placement for small cell networks"
    - "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)