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: "low complexity mimo precoding with discrete signals and statistical csi"
  Abstract: In this paper, we investigate the design of multiple-input multiple-output single-user precoders for finite-alphabet signals under the premise of statistical channel-state information at the transmitter. Based on an asymptotic expression for the mutual information of channels exhibiting antenna correlations, we propose a low-complexity iterative algorithm that radically reduces the computational load of existing approaches by orders of magnitude with only minimal losses in performance. The savings increase with the number of transmit antennas and with the cardinality of the signal alphabet, making it possible to supports values thereof that were unwieldy in existing solutions.

Connected through hyperedge HE-1 (induced by source paper "secure transmission with large numbers of antennas and finite alphabet inputs"):
  with members:
    - "physical layer security for spectrum sharing systems"
    - "linear precoding of data and artificial noise in secure massive mimo systems"
    - "a survey on wireless security technical challenges recent advances and future trends"
    - "secure massive mimo transmission with an active eavesdropper"
    - "large scale mimo relaying techniques for physical layer security af or df"
    - "multi antenna relay aided wireless physical layer security"
    - "linear precoding for the mimo multiple access channel with finite alphabet inputs and statistical csi"
    - "dealing with interference in distributed large scale mimo systems a statistical approach"

Connected through hyperedge HE-2 (induced by source paper "downlink precoding for massive mimo systems exploiting virtual channel model sparsity"):
  with members:
    - "spatial temporal bem and channel estimation strategy for massive mimo time varying systems"
    - "linear precoding for the mimo multiple access channel with finite alphabet inputs and statistical csi"
    - "kronecker product correlation model and limited feedback codebook design in a 3d channel model"
    - "large system analysis of correlated mimo multiple access channels with arbitrary signaling in the presence of interference"
    - "joint spatial division and multiplexing for mm wave channels"
    - "a coordinated approach to channel estimation in large scale multiple antenna systems"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "pilot contamination and precoding in multi cell tdd systems"

Connected through hyperedge HE-3 (induced by source paper "linear precoding for mimo channels with qam constellations and reduced complexity"):
  with members:
    - "linear precoding for the mimo multiple access channel with finite alphabet inputs and statistical csi"
    - "diversity analysis of bit interleaved coded multiple beamforming with orthogonal frequency division multiplexing"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "on optimal precoding in linear vector gaussian channels with arbitrary input distribution"
    - "constellation precoded multiple beamforming"
    - "pilot contamination and precoding in multi cell tdd 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)