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: "stationarity region of mm wave channel based on outdoor microcellular measurements at 28 ghz"
  Abstract: The stationarity region, i.e., the area in which the statistics of a propagation channel remain constant, is an important measure of the propagation channel, and essential for efficient system design. This paper presents what is to our knowledge the first extensive measurement campaign for measuring the stationarity region of MIMO mm-wave channels. Using a novel 28 GHz phased-array sounder with high phase stability, we present results in an urban microcell LoS, and LOS to NLOS transition region scenario, for the stationarity region of shadowing, power delay profile, and the angular power spectrum. A comparison to results at cm-waves shows considerably reduced stationarity region size, which has an important impact on system design.

Connected through hyperedge HE-1 (induced by source paper "suburban fixed wireless access channel measurements and models at 28 ghz for 90 outdoor coverage"):
  with members:
    - "suburban residential building penetration loss at 28 ghz for fixed wireless access"
    - "path loss beamforming gain and time dynamics measurements at 28 ghz for 90 indoor coverage"
    - "28 ghz microcell measurement campaign for residential environment"
    - "how much spectrum is too much in millimeter wave wireless access"
    - "small scale local area and transitional millimeter wave propagation for 5g communications"
    - "overview of millimeter wave communications for fifth generation 5g wireless networks with a focus on propagation models"
    - "gbps user rates using mmwave relayed backhaul with high gain antennas"
    - "5g 3gpp like channel models for outdoor urban microcellular and macrocellular environments"

Connected through hyperedge HE-2 (induced by source paper "real time deployment aspects of c band and millimeter wave 5g nr systems"):
  with members:
    - "millimeter wave extended nyusim channel model for spatial consistency"
    - "small scale local area and transitional millimeter wave propagation for 5g communications"
    - "hybrid beamforming for massive mimo a survey"

Connected through hyperedge HE-3 (induced by source paper "hybrid beamforming with selection for multiuser massive mimo systems"):
  with members:
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "5g 3gpp like channel models for outdoor urban microcellular and macrocellular environments"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "massive mimo combining with switches"
    - "hybrid beamforming for massive mimo a survey"
    - "analysis of the local quasi stationarity of measured dual polarized mimo channels"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"

Connected through hyperedge HE-4 (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"
    - "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 "dynamic double directional propagation channel measurements at 28 ghz"):
  with members:
    - "rapid fading due to human blockage in pedestrian crowds at 5g millimeter wave frequencies"

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)