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: "hierarchical cellular structures in high capacity cellular communication systems"
  Abstract: In the prevailing cellular environment, it is important to provide the resources for the fluctuating traffic demand exactly in the place and at the time where and when they are needed. In this paper, we explored the ability of hierarchical cellular structures with inter layer reuse to increase the capacity of mobile communication network by applying total frequency hopping (T-FH) and adaptive frequency allocation (AFA) as a strategy to reuse the macro and micro cell resources without frequency planning in indoor pico cells [11]. The practical aspects for designing macro- micro cellular overlays in the existing big urban areas are also explained [4]. Femto cells are inducted in macro / micro / pico cells hierarchical structure to achieve the required QoS cost effectively.

Connected through hyperedge HE-1 (induced by source paper "blip jit and footloose on the edge"):
  with members:
    - "stochastic service placement"

Connected through hyperedge HE-2 (induced by source paper "flexible design for alpha duplex communications in multi tier cellular networks"):
  with members:
    - "can uplink transmissions survive in full duplex cellular environments"
    - "modeling cellular networks in fading environments with dominant specular components"
    - "impact of directionality on interference mitigation in full duplex cellular network"
    - "throughput and coverage for a mixed full and half duplex small cell network"
    - "harvesting full duplex rate gains in cellular networks with half duplex user terminals"
    - "in band full duplex communications for cellular networks with partial uplink downlink overlap"
    - "limits on the capacity of in band full duplex communication in uplink cellular networks"
    - "full duplex radio for uplink downlink transmission with spatial randomness"

Connected through hyperedge HE-3 (induced by source paper "hybrid spectral efficient cellular network deployment to reduce rf pollution"):
  with members:
    - "r f pollution reduction in cellular communication"
    - "an intelligent approach for dense urban area in existing 2g 2 5g"
    - "proposed cellular network for indian conditions for enhancement of spectral density and reduction of power consumption rf pollution"
    - "survey of latest wireless cellular technologies for enhancement of spectral density at reduced cost"

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.CY(Computers and Society)