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: "network densification in 5g from the short range communications perspective"
  Abstract: Besides advanced telecommunications techniques, the most prominent evolution of wireless networks is the densification of network deployment. In particular, the increasing access points/users density and reduced cell size significantly enhance spatial reuse, thereby improving network capacity. Nevertheless, does network ultra-densification and over-deployment always boost the performance of wireless networks? Since the distance from transmitters to receivers is greatly reduced in dense networks, signal is more likely to be propagated from long- to short-range region. Without considering short-range propagation features, conventional understanding of the impact of network densification becomes doubtful. With this regard, it is imperative to reconsider the pros and cons brought by network densification. In this article, we first discuss the short-range propagation features in densely deployed network and verify through experimental results the validity of the proposed short-range propagation model. Considering short-range propagation, we further explore the fundamental impact of network densification on network capacity, aided by which a concrete interpretation of ultra-densification is presented from the network capacity perspective. Meanwhile, as short-range propagation makes interference more complicated and difficult to handle, we discuss possible approaches to further enhance network capacity in ultra-dense wireless networks. Moreover, key challenges are presented to suggest future directions.

Connected through hyperedge HE-1 (induced by source paper "robust energy efficient beamforming in misome swipt systems with proportional secrecy rate"):
  with members:
    - "robust secrecy energy efficient beamforming in misome swipt systems with proportional fairness"
    - "rf based energy harvesting in decode and forward relaying systems ergodic and outage capacities"
    - "secure beamforming in full duplex swipt systems with loopback self interference cancellation"
    - "large scale multiantenna multisine wireless power transfer"
    - "dynamic cross layer beamforming in hybrid powered communication systems with harvest use trade strategy"
    - "joint optimization of power and data transfer in multiuser mimo systems"
    - "robust resource allocation for mimo wireless powered communication networks based on a non linear eh model"
    - "wireless information and power transfer nonlinearity waveform design and rate energy tradeoff"

Connected through hyperedge HE-2 (induced by source paper "robust secrecy energy efficient beamforming in misome swipt systems with proportional fairness"):
  with members:
    - "secure beamforming in full duplex swipt systems with loopback self interference cancellation"
    - "robust energy efficient beamforming in misome swipt systems with proportional secrecy rate"
    - "large scale multiantenna multisine wireless power transfer"
    - "robust resource allocation for mimo wireless powered communication networks based on a non linear eh model"
    - "wireless information and power transfer nonlinearity waveform design and rate energy tradeoff"
    - "an overview of sustainable green 5g networks"
    - "communications and signals design for wireless power transmission"
    - "wireless powered communication opportunities and challenges"

Connected through hyperedge HE-3 (induced by source paper "limitation of sdma in ultra dense small cell networks"):
  with members:
    - "effect of densification on cellular network performance with bounded pathloss model"
    - "miso in ultra dense networks balancing the tradeoff between user and system performance"
    - "the intensity matching approach a tractable stochastic geometry approximation to system level analysis of cellular networks"
    - "downlink cellular network analysis with multi slope path loss models"
    - "downlink mimo hetnets modeling ordering results and performance analysis"
    - "multi antenna communication in ad hoc networks achieving mimo gains with simo transmission"

Connected through hyperedge HE-4 (induced by source paper "effects of base station spatial interdependence on interference correlation and network performance"):
  with members:
    - "temporal correlation of interference and outage in mobile networks over one dimensional finite regions"
    - "spatio temporal interference correlation and joint coverage in cellular networks"
    - "heterogeneous cellular networks with spatio temporal traffic delay analysis and scheduling"
    - "the intensity matching approach a tractable stochastic geometry approximation to system level analysis of cellular networks"
    - "cache enabled heterogeneous cellular networks optimal tier level content placement"
    - "analysis of interference correlation in non poisson networks"
    - "optimizing user association and spectrum allocation in hetnets a utility perspective"
    - "d2d enhanced heterogeneous cellular networks with dynamic tdd"

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)