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: "28 ghz and 73 ghz millimeter wave indoor propagation measurements and path loss models"
  Abstract: This paper presents 28 GHz and 73 GHz millimeter-wave propagation measurements performed in a typical office environment using a 400 Megachip-per-second broadband sliding correlator channel sounder and highly directional steerable 15 dBi (30° beamwidth) and 20 dBi (15° beamwidth) horn antennas. Power delay profiles were acquired for 48 transmitter-receiver location combinations over distances ranging from 3.9 m to 45.9 m with maximum transmit powers of 24 dBm and 12.3 dBm at 28 GHz and 73 GHz, respectively. Directional and omnidirectional path loss models and RMS delay spread statistics are presented for line-of-sight and non-line-of-sight environments for both co- and cross-polarized antenna configurations. The LOS omnidirectional path loss exponents were 1.1 and 1.3 at 28 GHz and 73 GHz, and 2.7 and 3.2 in NLOS at 28 GHz and 73 GHz, respectively, for vertically-polarized antennas. The mean directional RMS delay spreads were 18.4 ns and 13.3 ns, with maximum values of 193 ns and 288 ns at 28 GHz and 73 GHz, respectively.

Connected through hyperedge HE-1 (induced by source paper "cache enabled hetnets with millimeter wave small cells"):
  with members:
    - "modeling and analysis of mmwave communications in cache enabled hetnets"
    - "modeling and analysis of d2d millimeter wave networks with poisson cluster processes"
    - "modeling and analyzing millimeter wave cellular systems"
    - "coverage analysis for millimeter wave networks the impact of directional antenna arrays"
    - "non orthogonal multiple access in large scale heterogeneous networks"
    - "caching policy toward maximal success probability and area spectral efficiency of cache enabled hetnets"
    - "downlink and uplink cell association with traditional macrocells and millimeter wave small cells"
    - "downlink cell association and load balancing for joint millimeter wave microwave cellular networks"

Connected through hyperedge HE-2 (induced by source paper "modeling and analysis of d2d millimeter wave networks with poisson cluster processes"):
  with members:
    - "nonorthogonal multiple access in large scale underlay cognitive radio networks"
    - "wireless device to device caching networks basic principles and system performance"
    - "cellular base station assisted device to device communications in tv white space"
    - "modeling and performance analysis of clustered device to device networks"
    - "cooperative non orthogonal multiple access with simultaneous wireless information and power transfer"
    - "d2d enhanced heterogeneous cellular networks with dynamic tdd"
    - "an analytical framework for device to device communication in cellular networks"
    - "spectrum sharing for device to device communication in cellular networks"

Connected through hyperedge HE-3 (induced by source paper "modeling and analysis of mmwave communications in cache enabled hetnets"):
  with members:
    - "modeling and analysis of d2d millimeter wave networks with poisson cluster processes"
    - "modeling and analyzing millimeter wave cellular systems"
    - "coverage analysis for millimeter wave networks the impact of directional antenna arrays"
    - "non orthogonal multiple access in large scale heterogeneous networks"
    - "caching policy toward maximal success probability and area spectral efficiency of cache enabled hetnets"
    - "downlink and uplink cell association with traditional macrocells and millimeter wave small cells"
    - "energy efficiency of downlink networks with caching at base stations"
    - "enhancing the physical layer security of non orthogonal multiple access in large scale networks"

Connected through hyperedge HE-4 (induced by source paper "exploiting multiple access in clustered millimeter wave networks noma or oma"):
  with members:
    - "modeling and analysis of d2d millimeter wave networks with poisson cluster processes"
    - "modeling and analyzing millimeter wave cellular systems"
    - "coverage analysis for millimeter wave networks the impact of directional antenna arrays"
    - "non orthogonal multiple access in large scale heterogeneous networks"
    - "enhancing the physical layer security of non orthogonal multiple access in large scale networks"
    - "modeling and performance analysis of clustered device to device networks"
    - "fairness for non orthogonal multiple access in 5g systems"
    - "tractable model for rate in self backhauled millimeter wave cellular networks"

Connected through hyperedge HE-5 (induced by source paper "position locationing for millimeter wave systems"):
  with members:
    - "propagation measurement system and approach at 140 ghz moving to 6g and above 100 ghz"
    - "base station diversity propagation measurements at 73 ghz millimeter wave for 5g coordinated multipoint comp analysis"
    - "initial access in 5g mmwave cellular networks"
    - "millimeter wave distance dependent large scale propagation measurements and path loss models for outdoor and indoor 5g systems"

Connected through hyperedge HE-6 (induced by source paper "overview of millimeter wave communications for fifth generation 5g wireless networks with a focus on propagation models"):
  with members:
    - "indoor office wideband penetration loss measurements at 73 ghz"
    - "study on 3gpp rural macrocell path loss models for millimeter wave wireless communications"
    - "investigation and comparison of 3gpp and nyusim channel models for 5g wireless communications"
    - "millimeter wave small scale spatial statistics in an urban microcell scenario"
    - "a novel millimeter wave channel simulator and applications for 5g wireless communications"
    - "small scale local area and transitional millimeter wave propagation for 5g communications"
    - "5g 3gpp like channel models for outdoor urban microcellular and macrocellular environments"
    - "millimeter wave human blockage at 73 ghz with a simple double knife edge diffraction model and extension for directional antennas"

Connected through hyperedge HE-7 (induced by source paper "wireless powered dense cellular networks how many small cells do we need"):
  with members:
    - "user association in 5g networks a survey and an outlook"
    - "tractable resource management with uplink decoupled millimeter wave overlay in ultra dense cellular networks"
    - "wireless power transfer in massive mimo aided hetnets with user association"
    - "millimeter wave energy harvesting"
    - "performance analysis of ambient rf energy harvesting with repulsive point process modeling"
    - "millimeter wave power transfer and information transmission"
    - "deploying dense networks for maximal energy efficiency small cells meet massive mimo"
    - "5g ultra dense cellular networks"

Connected through hyperedge HE-8 (induced by source paper "optimal user scheduling and power allocation for millimeter wave noma systems"):
  with members:
    - "optimal resource allocation for power efficient mc noma with imperfect channel state information"
    - "fundamental green tradeoffs progresses challenges and impacts on 5g networks"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "sub channel assignment power allocation and user scheduling for non orthogonal multiple access networks"
    - "an overview of sustainable green 5g networks"
    - "optimal joint power and subcarrier allocation for full duplex multicarrier non orthogonal multiple access systems"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "a minorization maximization method for optimizing sum rate in the downlink of non orthogonal multiple access systems"

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)