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: "precoding in multibeam satellite communications present and future challenges"
  Abstract: Whenever multibeam satellite systems target very aggressive frequency reuse in their coverage area, inter-beam interference becomes the major obstacle for increasing the overall system throughput. As a matter of fact, users located at the beam edges suffer from very large interference for even a moderately aggressive planning of reuse-2. Although solutions for inter-beam interference management have been investigated at the satellite terminal, it turns out that the performance improvement does not justify the increased terminal complexity and cost. In this article, we pay attention to interference mitigation techniques that take place at the transmitter (i.e., the gateway). Based on this understanding, we provide our vision on advanced precoding techniques and user clustering methods for multibeam broadband fixed satellite communications. We also discuss practical challenges to deploy precoding schemes and the support introduced in the recently published DVB-S2X standard. Future challenges for novel configurations employing precoding are also provided.

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"
    - "multicast multigroup precoding and user scheduling for frame based satellite communications"
    - "multicast multigroup beamforming under per antenna power constraints"
    - "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 "rate splitting for max min fair multigroup multicast beamforming in overloaded systems"):
  with members:
    - "generalized multicast multibeam precoding for satellite communications"
    - "an overview on resource allocation techniques for multi user mimo systems"
    - "elevated multiplexing and signal space partitioning in the 2 user mimo ic with partial csit"
    - "sum rate maximization for linearly precoded downlink multiuser miso systems with partial csit a rate splitting approach"
    - "robust transmission in downlink multiuser miso systems a rate splitting approach"
    - "a rate splitting strategy for max min fair multigroup multicasting"
    - "overloaded multiuser miso transmission with imperfect csit"
    - "rate splitting for mimo wireless networks a promising phy layer strategy for lte evolution"

Connected through hyperedge HE-3 (induced by source paper "energy efficient coordinated multi cell multi group multicast beamforming with antenna selection"):
  with members:
    - "energy efficient beam coordination strategies with rate dependent processing power"
    - "content centric sparse multicast beamforming for cache enabled cloud ran"
    - "multicast multigroup precoding and user scheduling for frame based satellite communications"
    - "energy efficient scheduling and power allocation in downlink ofdma networks with base station coordination"
    - "weighted fair multicast multigroup beamforming under per antenna power constraints"
    - "coordinated multicast beamforming in multicell networks"
    - "framework for link level energy efficiency optimization with informed transmitter"

Connected through hyperedge HE-4 (induced by source paper "symbol level multiuser miso precoding for multi level adaptive modulation"):
  with members:
    - "energy efficient symbol level precoding in multiuser miso based on relaxed detection region"
    - "directional modulation via symbol level precoding a way to enhance security"
    - "constructive interference through symbol level precoding for multi level modulation"
    - "constructive multiuser interference in symbol level precoding for the miso downlink channel"
    - "energy efficient symbol level precoding in multiuser miso channels"
    - "exploiting known interference as green signal power for downlink beamforming optimization"
    - "multicast multigroup precoding and user scheduling for frame based satellite communications"
    - "optimal multiuser transmit beamforming a difficult problem with a simple solution structure"

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)