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: "three practical aspects of massive mimo intermittent user activity pilot synchronism and asymmetric deployment"
  Abstract: This paper considers three aspects of Massive MIMO (multiple-input multiple-output) communication networks that have received little attention in previous works, but are important to understand when designing and implementing this promising wireless technology. First, we analyze how bursty data traffic behaviors affect the system. Using a probabilistic model for intermittent user activity, we show that the spectral efficiency (SE) scales gracefully with reduced user activity. Then, we make an analytic comparison between synchronous and asynchronous pilot signaling, and prove that the choice between these has no impact on the SE. Finally, we provide an analytical and numerical study of the SE achieved with random network deployment.

Connected through hyperedge HE-1 (induced by source paper "asynchronous downlink massive mimo networks a stochastic geometry approach"):
  with members:
    - "stochastic geometry modeling and analysis of single and multi cluster wireless networks"
    - "deploying dense networks for maximal energy efficiency small cells meet massive mimo"
    - "analyzing uplink sinr and rate in massive mimo systems using stochastic geometry"
    - "coverage and rate analysis for millimeter wave cellular networks"
    - "what will 5g be"
    - "analytical modeling of uplink cellular networks"
    - "a tractable approach to coverage and rate in cellular networks"
    - "pilot contamination and precoding in multi cell tdd systems"

Connected through hyperedge HE-2 (induced by source paper "an overview on resource allocation techniques for multi user mimo systems"):
  with members:
    - "low complexity downlink user selection for massive mimo systems"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "user association in 5g networks a survey and an outlook"
    - "cell free massive mimo versus small cells"
    - "mu mimo mac protocols for wireless local area networks a survey"
    - "on the number of rf chains and phase shifters and scheduling design with hybrid analog digital beamforming"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"

Connected through hyperedge HE-3 (induced by source paper "cell edge aware precoding for downlink massive mimo cellular networks"):
  with members:
    - "distributed optimization of hierarchical small cell networks a gnep framework"
    - "massive mimo ten myths and one critical question"
    - "operating massive mimo in unlicensed bands for enhanced coexistence and spatial reuse"
    - "energy efficient design of mimo heterogeneous networks with wireless backhaul"
    - "a stochastic geometry framework for analyzing pairwise cooperative cellular networks"
    - "fractional pilot reuse in massive mimo systems"
    - "a tractable model for noncoherent joint transmission base station cooperation"
    - "linear precoding based on polynomial expansion large scale multi cell mimo systems"

Connected through hyperedge HE-4 (induced by source paper "a random access protocol for pilot allocation in crowded massive mimo systems"):
  with members:
    - "random access in uplink massive mimo systems how to exploit asynchronicity and excess antennas"
    - "massive mimo ten myths and one critical question"
    - "random access for massive mimo systems with intra cell pilot contamination"
    - "random access protocol for massive mimo strongest user collision resolution sucr"
    - "massive mimo for crowd scenarios a solution based on random access"
    - "coded random access applying codes on graphs to design random access protocols"
    - "massive mimo systems with non ideal hardware energy efficiency estimation and capacity limits"
    - "coded random access how coding theory helps to build random access protocols"

Connected through hyperedge HE-5 (induced by source paper "random pilot and data access in massive mimo for machine type communications"):
  with members:
    - "a random access protocol for pilot allocation in crowded massive mimo systems"
    - "random access in uplink massive mimo systems how to exploit asynchronicity and excess antennas"
    - "coded pilot access a random access solution for massive mimo systems"
    - "massive mimo ten myths and one critical question"
    - "random access for massive mimo systems with intra cell pilot contamination"
    - "towards very large aperture massive mimo a measurement based study"
    - "random access protocol for massive mimo strongest user collision resolution sucr"
    - "massive mimo for crowd scenarios a solution based on random access"

Connected through hyperedge HE-6 (induced by source paper "superimposed pilots are superior for mitigating pilot contamination in massive mimo part ii performance analysis and hybrid system design"):
  with members:
    - "superimposed pilots are superior for mitigating pilot contamination in massive mimo"
    - "pilot contamination is not a fundamental asymptotic limitation in massive mimo"
    - "massive mimo for next generation wireless systems"
    - "what will 5g be"
    - "blind pilot decontamination"
    - "massive mimo for maximal spectral efficiency how many users and pilots should be allocated"
    - "five disruptive technology directions for 5g"
    - "on an achievable rate of large rayleigh block fading mimo channels with no csi"

Connected through hyperedge HE-7 (induced by source paper "random access for massive mimo systems with intra cell pilot contamination"):
  with members:
    - "massive mimo ten myths and one critical question"
    - "massive mimo for crowd scenarios a solution based on random access"
    - "massive mimo for next generation wireless systems"
    - "massive mimo for maximal spectral efficiency how many users and pilots should be allocated"
    - "achieving massive mimo spectral efficiency with a not so large number of antennas"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "pilot contamination and precoding in multi cell tdd systems"

Connected through hyperedge HE-8 (induced by source paper "random access protocol for massive mimo strongest user collision resolution sucr"):
  with members:
    - "massive mimo for crowd scenarios a solution based on random access"
    - "massive mimo for maximal spectral efficiency how many users and pilots should be allocated"
    - "five disruptive technology directions for 5g"
    - "achieving massive mimo spectral efficiency with a not so large number of antennas"
    - "code expanded random access for machine type communications"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "pilot contamination and precoding in multi cell tdd 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)