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: "providing local content in a hybrid single frequency network using hierarchical modulation"
  Abstract: A hierarchical modulation method is proposed for providing local content in a hybrid satellite and terrestrial single frequency network such DVB-SH. The hierarchical modulation is used to transmit both global and local content in terrestrial transmitters. The global content is transmitted with high priority layer of the hierarchical modulation, and the local content is modulated with the low priority layer of the hierarchical modulation. The satellite transmits global content only. The performance of the hierarchical system for both global and local content is analyzed.

Connected through hyperedge HE-1 (induced by source paper "64 apsk constellation and mapping optimization for satellite broadcasting using genetic algorithms"):
  with members:
    - "on the genetic optimization of apsk constellations for satellite broadcasting"
    - "random access in dvb rcs2 design and dynamic control for congestion avoidance"
    - "a hierarchical modulation for upgrading digital broadcast systems"
    - "constellation design for transmission over nonlinear satellite channels"
    - "combining adaptive coding and modulation with hierarchical modulation in satcom systems"

Connected through hyperedge HE-2 (induced by source paper "dvb s2 spectrum efficiency improvement with hierarchical modulation"):
  with members:
    - "a hierarchical modulation for upgrading digital broadcast systems"
    - "generic approach for hierarchical modulation performance analysis application to dvb sh"
    - "combining adaptive coding and modulation with hierarchical modulation in satcom systems"

Connected through hyperedge HE-3 (induced by source paper "combining adaptive coding and modulation with hierarchical modulation in satcom systems"):
  with members:
    - "a hierarchical modulation for upgrading digital broadcast systems"
    - "generic approach for hierarchical modulation performance analysis application to dvb sh"
    - "improving broadcast channel rate using hierarchical modulation"

Connected through hyperedge HE-4 (induced by source paper "improving broadcast channel rate using hierarchical modulation"):
  with members:
    - "generic approach for hierarchical modulation performance analysis application to dvb sh"

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)