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: "quad led complex modulation qcm for visible light wireless communication"
  Abstract: In this paper, we propose a simple and novel complex modulation scheme for multiple-LED wireless communication, termed as {\em quad-LED complex modulation (QCM)}. The proposed QCM scheme uses four LEDs (hence the name `quad-LED'), one LED each to map positive real, negative real, positive imaginary, and negative imaginary parts of complex modulation symbols like QAM/PSK symbols. The QCM scheme does not need Hermitian symmetry operation to generate LED compatible positive real transmit signals. Instead it exploits spatial indexing of LEDs to convey sign information. The proposed QCM module can serve as a basic building block to bring in the benefits of complex modulation to VLC. For example, QCM with phase rotation (QAM-PR) where the complex modulation symbols are rotated in phase before mapping the signals to the LEDs achieves improved bit error performance. We also find that the proposed QCM when used along with OFDM, termed as QCM-OFDM, achieves very good performance.

Connected through hyperedge HE-1 (induced by source paper "ofdm based optical spatial modulation"):
  with members:
    - "bidirectional user throughput maximization based on feedback reduction in lifi networks"

Connected through hyperedge HE-2 (induced by source paper "quad led and dual led complex modulation for visible light communication"):
  with members:
    - "generalized spatial modulation in indoor wireless visible light communication"
    - "coded index modulation for non dc biased ofdm in multiple led visible light communication"
    - "flip ofdm for unipolar communication systems"
    - "flip ofdm for optical wireless communications"

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)