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 millimeter wave ultrawideband small scale fading models in wireless channels"
  Abstract: This paper presents small-scale fading measurements for 28 GHz outdoor millimeter-wave ultrawideband channels using directional horn antennas at the transmitter and receiver. Power delay profiles were measured at half-wavelength spatial increments over a local area (33 wavelengths) on a linear track in two orthogonal receiver directions in a typical base-to-mobile scenario with fixed transmitter and receiver antenna beam pointing directions. The voltage path amplitudes are shown to follow a Rician distribution, with K-factor ranging from 9 - 15 dB and 5 - 8 dB in line of sight (LOS) and non-line of sight (NLOS) for a vertical-to-vertical co- polarized antenna scenario, respectively, and from 3 - 7 dB in both LOS and NLOS vertical-to- horizontal cross-polarized antenna scenario. The average spatial autocorrelation functions of individual multipath components reveal that signal amplitudes reach a correlation of 0 after 2 and 5 wavelengths in LOS and NLOS co-polarized V-V antenna scenarios. The models provided are useful for recreating path gain statistics of millimeter- wave wideband channel impulse responses over local areas, for the study of multi-element antenna simulations and channel estimation algorithms.

Connected through hyperedge HE-1 (induced by source paper "fast accurate beam and channel tracking for two dimensional phased antenna array"):
  with members:
    - "how to mobilize mmwave a joint beam and channel tracking approach"
    - "analog beam tracking in linear antenna arrays convergence optimality and performance"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "auxiliary beam pair enabled aod and aoa estimation in closed loop large scale mmwave mimo systems"
    - "mobile millimeter wave channel acquisition tracking and abrupt change detection"
    - "enabling uav cellular with millimeter wave communication potentials and approaches"
    - "hybrid beamforming for massive mimo a survey"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"

Connected through hyperedge HE-2 (induced by source paper "explore and eliminate optimized two stage search for millimeter wave beam alignment"):
  with members:
    - "hybrid beamforming where should the analog power amplifiers be placed"
    - "millimeter wave beam alignment large deviations analysis and design insights"
    - "millimeter wave mimo channel estimation using overlapped beam patterns and rate adaptation"
    - "inverse multipath fingerprinting for millimeter wave v2i beam alignment"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "millimeter wave vehicular communication to support massive automotive sensing"
    - "codebook design for millimeter wave channel estimation with hybrid precoding structure"
    - "directional cell discovery in millimeter wave cellular networks"

Connected through hyperedge HE-3 (induced by source paper "how to mobilize mmwave a joint beam and channel tracking approach"):
  with members:
    - "analog beam tracking in linear antenna arrays convergence optimality and performance"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "tracking mm wave channel dynamics fast beam training strategies under mobility"
    - "hybrid beamforming for massive mimo a survey"
    - "compressed sensing based multi user millimeter wave systems how many measurements are needed"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "five disruptive technology directions for 5g"

Connected through hyperedge HE-4 (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-5 (induced by source paper "small scale local area and transitional millimeter wave propagation for 5g communications"):
  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"
    - "a flexible wideband millimeter wave channel sounder with local area and nlos to los transition measurements"
    - "millimeter wave small scale spatial statistics in an urban microcell scenario"
    - "a novel millimeter wave channel simulator and applications for 5g wireless communications"
    - "overview of millimeter wave communications for fifth generation 5g wireless networks with a focus on propagation models"
    - "stationarity region of mm wave channel based on outdoor microcellular measurements at 28 ghz"

Connected through hyperedge HE-6 (induced by source paper "stationarity region of mm wave channel based on outdoor microcellular measurements at 28 ghz"):
  with members:
    - "a flexible wideband millimeter wave channel sounder with local area and nlos to los transition measurements"
    - "millimeter wave small scale spatial statistics in an urban microcell scenario"
    - "small scale local area and transitional millimeter wave propagation for 5g communications"
    - "5g 3gpp like channel models for outdoor urban microcellular and macrocellular environments"
    - "what will 5g be"
    - "millimeter wave cellular wireless networks potentials and challenges"

Connected through hyperedge HE-7 (induced by source paper "millimeter wave small scale spatial statistics in an urban microcell scenario"):
  with members:
    - "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"
    - "millimeter wave wireless communications new results for rural connectivity"
    - "synthesizing omnidirectional antenna patterns received power and path loss from directional antennas for 5g millimeter wave communications"

Connected through hyperedge HE-8 (induced by source paper "new results on the fluctuating two ray model with arbitrary fading parameters and its applications"):
  with members:
    - "the fluctuating two ray fading model statistical characterization and performance analysis"
    - "mgf approach to the analysis of generalized two ray fading models"
    - "five disruptive technology directions for 5g"

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)