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: "performance analysis of ultra dense networks with elevated base stations"
  Abstract: This paper analyzes the downlink performance of ultra-dense networks with elevated base stations (BSs). We consider a general dual-slope pathloss model with distance-dependent probability of line-of-sight (LOS) transmission between BSs and receivers. Specifically, we consider the scenario where each link may be obstructed by randomly placed buildings. Using tools from stochastic geometry, we show that both coverage probability and area spectral efficiency decay to zero as the BS density grows large. Interestingly, we show that the BS height alone has a detrimental effect on the system performance even when the standard single-slope pathloss model is adopted.

Connected through hyperedge HE-1 (induced by source paper "optimal base station antenna downtilt in downlink cellular networks"):
  with members:
    - "ultra dense networks is there a limit to spatial spectrum reuse"
    - "performance impact of base station antenna heights in dense cellular networks"
    - "joint tilt angle adaptation and beamforming in multicell multiuser cellular networks"
    - "energy efficiency optimization of 5g radio frequency chain systems"
    - "please lower small cell antenna heights in 5g"
    - "performance impact of los and nlos transmissions in dense cellular networks"
    - "spatial spectrum and energy efficiency of random cellular networks"
    - "towards 1 gbps ue in cellular systems understanding ultra dense small cell deployments"

Connected through hyperedge HE-2 (induced by source paper "downlink cellular network analysis with los nlos propagation and elevated base stations"):
  with members:
    - "sinr and throughput of dense cellular networks with stretched exponential path loss"
    - "modeling and analyzing millimeter wave cellular systems"
    - "performance limits of network densification"
    - "power beacon assisted millimeter wave ad hoc networks"
    - "a 3 d spatial model for in building wireless networks with correlated shadowing"
    - "coverage and capacity scaling laws in downlink ultra dense cellular networks"
    - "study on the idle mode capability with los and nlos transmissions"
    - "impact of los nlos propagation and path loss in ultra dense cellular networks"

Connected through hyperedge HE-3 (induced by source paper "ultra dense networks is there a limit to spatial spectrum reuse"):
  with members:
    - "on the performance of practical ultra dense networks the major and minor factors"
    - "performance impact of base station antenna heights in dense cellular networks"
    - "the intensity matching approach a tractable stochastic geometry approximation to system level analysis of cellular networks"
    - "performance impact of idle mode capability on dense small cell networks"
    - "performance impact of los and nlos transmissions in dense cellular networks"
    - "towards 1 gbps ue in cellular systems understanding ultra dense small cell deployments"
    - "downlink cellular network analysis with multi slope path loss models"
    - "coverage and rate analysis for millimeter wave cellular networks"

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)