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: "multicast multigroup beamforming under per antenna power constraints"
  Abstract: Linear precoding exploits the spatial degrees of freedom offered by multi-antenna transmitters to serve multiple users over the same frequency resources. The present work focuses on simultaneously  ...

Connected through hyperedge HE-1 (induced by source paper "distributed optimization for coordinated beamforming in multicell multigroup multicast systems power minimization and sinr balancing"):
  with members:
    - "energy efficient beam coordination strategies with rate dependent processing power"
    - "cooperative channel estimation for coordinated transmission with limited backhaul"
    - "distributed coordinated beamforming for multi cell multigroup multicast systems"
    - "precoding in multibeam satellite communications present and future challenges"
    - "multicast multigroup precoding and user scheduling for frame based satellite communications"
    - "weighted fair multicast multigroup beamforming under per antenna power constraints"
    - "coordinated multicast beamforming in multicell networks"
    - "distributed robust multicell coordinated beamforming with imperfect csi an admm approach"

Connected through hyperedge HE-2 (induced by source paper "distributed coordinated beamforming for multi cell multigroup multicast systems"):
  with members:
    - "sum rate maximizing multigroup multicast beamforming under per antenna power constraints"
    - "weighted fair multicast multigroup beamforming under per antenna power constraints"
    - "coordinated multicast beamforming in multicell networks"
    - "distributed multicell beamforming design approaching pareto boundary with max min fairness"

Connected through hyperedge HE-3 (induced by source paper "multicast multigroup precoding and user scheduling for frame based satellite communications"):
  with members:
    - "optimal multiuser transmit beamforming a difficult problem with a simple solution structure"
    - "sum rate maximizing multigroup multicast beamforming under per antenna power constraints"
    - "frame based precoding in satellite communications a multicast approach"
    - "weighted fair multicast multigroup beamforming under per antenna power constraints"
    - "user scheduling for coordinated dual satellite systems with linear precoding"
    - "multi gateway cooperation in multibeam satellite systems"
    - "generic optimization of linear precoding in multibeam satellite systems"

Connected through hyperedge HE-4 (induced by source paper "multicast multigroup beamforming for per antenna power constrained large scale arrays"):
  with members:
    - "weighted fair multicast multigroup beamforming under per antenna power constraints"
    - "scaling up mimo opportunities and challenges with very large arrays"

Connected through hyperedge HE-5 (induced by source paper "frame based precoding in satellite communications a multicast approach"):
  with members:
    - "sum rate maximizing multigroup multicast beamforming under per antenna power constraints"
    - "weighted fair multicast multigroup beamforming under per antenna power constraints"
    - "mmse performance analysis of generalized multibeam satellite channels"
    - "generic optimization of linear precoding in multibeam satellite systems"

Connected through hyperedge HE-6 (induced by source paper "weighted fair multicast multigroup beamforming under per antenna power constraints"):
  with members:
    - "frame based precoding in satellite communications a multicast approach"
    - "coordinated multicast beamforming in multicell networks"
    - "generic optimization of linear precoding in multibeam satellite systems"

Connected through hyperedge HE-7 (induced by source paper "sum rate maximizing multigroup multicast beamforming under per antenna power constraints"):
  with members:
    - "weighted fair multicast multigroup beamforming under per antenna power constraints"

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)