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: "impact of multipath reflections on the performance of indoor visible light positioning systems"
  Abstract: Visible light communication (VLC) using light-emitting-diodes (LEDs) has been a popular research area recently. VLC can provide a practical solution for indoor positioning. In this paper, the impact of multipath reflections on a two-dimensional indoor VLC positioning is investigated, considering a complex indoor environment with walls, floor, and ceiling. For the proposed positioning system, an LED bulb is the transmitter and a photo-diode is the receiver to detect received signal strength information. Combined deterministic and modified Monte Carlo method is applied to compute the impulse response of the optical channel. Since power attenuation is applied to calculate the distance between the transmitter and receiver, the received power from each reflection order is analyzed. The positioning errors are further estimated for all the locations over the room and compared with the previous works where no reflections considered. Finally, calibration approaches are proposed to decrease the effect of multipath reflections.

Connected through hyperedge HE-1 (induced by source paper "localisation communication and networking with vlc challenges and opportunities"):
  with members:
    - "adaptive coding and modulation for large scale antenna array based aeronautical communications in the presence of co channel interference"
    - "non orthogonal multiple access for visible light communications"
    - "flip ofdm for unipolar communication systems"

Connected through hyperedge HE-2 (induced by source paper "light fidelity li fi based indoor communication system"):
  with members:
    - "an overview of visible light communication systems"

Connected through hyperedge HE-3 (induced by source paper "indoor location estimation with optical based ofdm communications"):
  with members:
    - "indoor positioning in high speed ofdm visible light communications"
    - "robust timing synchronization for ac ofdm based optical wireless communications"
    - "on the performance of single and multi carrie modulation schemes for indoor visible light communication systems"
    - "flip ofdm for unipolar communication 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)