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: "harvest the potential of massive mimo with multi layer techniques"
  Abstract: Massive MIMO is envisioned as a promising technology for 5G wireless networks due to its high potential to improve both spectral and energy efficiency. Although the massive MIMO system is based on innovations in the physical layer, the upper layer techniques also play important roles in harvesting the performance gains of massive MIMO. In this article, we begin with an analysis of the benefits and challenges of massive MIMO systems. We then investigate the multi-layer techniques for incorporating massive MIMO in several important network deployment scenarios. We conclude this article with a discussion of open and potential problems for future research.

Connected through hyperedge HE-1 (induced by source paper "energy efficient massive mimo through distributed precoder design"):
  with members:
    - "joint user scheduling and beam selection optimization for beam based massive mimo downlinks"
    - "green 5g heterogeneous networks through dynamic small cell operation"
    - "the concrete distribution a continuous relaxation of discrete random variables"
    - "massive mimo ten myths and one critical question"
    - "large scale convex optimization for dense wireless cooperative networks"
    - "distributed constrained optimization by consensus based primal dual perturbation method"
    - "massive mimo meets hetnet interference coordination through spatial blanking"
    - "distributed robust multicell coordinated beamforming with imperfect csi an admm approach"

Connected through hyperedge HE-2 (induced by source paper "boost base station on off switching strategy for energy efficient massive mimo hetnets"):
  with members:
    - "user association in massive mimo hetnets"
    - "what will 5g be"
    - "massive mimo and small cells improving energy efficiency by optimal soft cell coordination"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "user association for load balancing in heterogeneous cellular networks"
    - "green cellular networks a survey some research issues and challenges"
    - "energy and spectral efficiency of very large multiuser mimo systems"

Connected through hyperedge HE-3 (induced by source paper "interference management in massive mimo hetnets a nested array approach"):
  with members:
    - "user association in massive mimo hetnets"
    - "boost base station on off switching strategy for energy efficient massive mimo hetnets"
    - "what will 5g be"
    - "massive mimo meets hetnet interference coordination through spatial blanking"
    - "massive mimo and small cells improving energy efficiency by optimal soft cell coordination"
    - "energy and spectral efficiency of very large multiuser mimo 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.NI(Networking and Internet Architecture)