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: "pilot decontamination in cmt based massive mimo networks"
  Abstract: Pilot contamination problem in massive MIMO networks operating in time-division duplex (TDD) mode can limit their expected capacity to a great extent. This paper addresses this problem in cosine modulated multitone (CMT) based massive MIMO networks; taking advantage of their so-called blind equalization property. We extend and apply the blind equalization technique from single antenna case to multi-cellular massive MIMO systems and show that it can remove the channel estimation errors (due to pilot contamination effect) without any need for cooperation between different cells or transmission of additional training information. Our numerical results advocate the efficacy of the proposed blind technique in improving the channel estimation accuracy and removal of the residual channel estimation errors caused by the users of the other cells.

Connected through hyperedge HE-1 (induced by source paper "filter bank multicarrier in massive mimo analysis and channel equalization"):
  with members:
    - "prototype filter design for fbmc in massive mimo channels"
    - "cell free massive mimo versus small cells"
    - "ofdm without cp in massive mimo"
    - "frequency spreading equalization in multicarrier massive mimo"
    - "impact of timing and frequency offsets on multicarrier waveform candidates for 5g"
    - "filter bank multicarrier for massive mimo"
    - "five disruptive technology directions for 5g"
    - "scaling up mimo opportunities and challenges with very large arrays"

Connected through hyperedge HE-2 (induced by source paper "prototype filter design for fbmc in massive mimo channels"):
  with members:
    - "massive mimo and waveform design for 5th generation wireless communication systems"
    - "frequency spreading equalization in multicarrier massive mimo"
    - "impact of timing and frequency offsets on multicarrier waveform candidates for 5g"
    - "filter bank multicarrier for massive mimo"
    - "five disruptive technology directions for 5g"
    - "energy and spectral efficiency of very large multiuser mimo systems"

Connected through hyperedge HE-3 (induced by source paper "massive mimo and waveform design for 5th generation wireless communication systems"):
  with members:
    - "achievable rates of fdd massive mimo systems with spatial channel correlation"
    - "filter bank multicarrier for massive mimo"
    - "massive mimo for next generation wireless systems"
    - "what will 5g be"
    - "blind pilot decontamination"
    - "modulation formats and waveforms for the physical layer of 5g wireless networks who will be the heir of ofdm"
    - "generalized design of low complexity block diagonalization type precoding algorithms for multiuser mimo systems"
    - "scalable synchronization and reciprocity calibration for distributed multiuser mimo"

Connected through hyperedge HE-4 (induced by source paper "a simple dft aided spatial basis expansion model and channel estimation strategy for massive mimo systems"):
  with members:
    - "pilot reuse for massive mimo transmission over spatially correlated rayleigh fading channels"
    - "massive mimo multicasting in noncooperative cellular networks"
    - "an esprit based approach for 2 d localization of incoherently distributed sources in massive mimo systems"
    - "distributed compressive csit estimation and feedback for fdd multi user massive mimo systems"
    - "massive mimo for next generation wireless systems"
    - "downlink training techniques for fdd massive mimo systems open loop and closed loop training with memory"
    - "blind pilot decontamination"
    - "five disruptive technology directions for 5g"

Connected through hyperedge HE-5 (induced by source paper "frequency spreading equalization in multicarrier massive mimo"):
  with members:
    - "filter bank multicarrier for massive mimo"
    - "what will 5g be"
    - "scaling up mimo opportunities and challenges with very large arrays"

Connected through hyperedge HE-6 (induced by source paper "filter bank multicarrier for massive mimo"):
  with members:
    - "frequency spreading equalization in multicarrier massive mimo"
    - "blind pilot decontamination"
    - "uplink linear receivers for multi cell multiuser mimo with pilot contamination large system analysis"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "a coordinated approach to channel estimation in large scale multiple antenna 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)