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: "free space optical communication with spatial modulation and coherent detection over h k atmospheric turbulence channels"
  Abstract: The use of optical spatial modulation (OSM) is proposed as a simple low-complexity means of achieving spatial diversity in coherent free-space optical (FSO) communication systems. In doing so, this paper presents a generic analytical framework for obtaining the average bit error probability (ABEP) of uncoded and coded OSM with coherent detection in the presence of turbulence-induced fading. Although the framework is general enough to accommodate any type of channel models based on turbulence scattering, the focus of the analysis is on the H-K distribution as such model is very general and valid over a wide range of atmospheric propagation conditions. Using this framework, it is shown that OSM can offer comparable performance with conventional coherent FSO schemes employing spatial diversity at the transmitter or the receiver only, while outperforming the latter in terms of spectral efficiency and hardware complexity. Furthermore, various numerical performance evaluation results are also presented and compared with equivalent results obtained by Monte Carlo simulations which verify the accuracy of the derived analytical expressions.

Connected through hyperedge HE-1 (induced by source paper "a survey on spatial modulation in emerging wireless systems research progresses and applications"):
  with members:
    - "spatial modulation assisted multi antenna non orthogonal multiple access"
    - "adaptive spatial modulation based visible light communications ser analysis and optimization"
    - "two high performance schemes of transmit antenna selection for secure spatial modulation"
    - "receive spatial modulation for massive mimo systems"
    - "polarization shift keying polarsk system scheme and performance analysis"
    - "space time channel modulation"
    - "on the achievable spectral efficiency of spatial modulation aided downlink non orthogonal multiple access"
    - "spectral efficient analog precoding for generalized spatial modulation aided mmwave mimo"

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)