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: "superimposed pilots are superior for mitigating pilot contamination in massive mimo part ii performance analysis and hybrid system design"
  Abstract: In this part of the two part paper, the claim in Part I, that superimposed pilots are superior at mitigating pilot contamination in massive multiple-input multiple-output (MIMO) systems, is bolstered through additional performance metrics such as mean-squared error (MSE) and downlink signal-to-interference plus noise ratio (SINR). For a system employing superimposed pilots, it is shown that the MSE of the channel estimate diminishes with increasing number of antennas at the base station (BS), with the MSE achieving its Cramer-Rao lower bound asymptotically. The downlink (DL) SINR is also shown to increase without bound at a rate proportional to the square root of the number of antennas at the BS. Furthermore, we extend the concept of the hybrid system and propose a framework for partitioning users into those that employ superimposed pilots and to those that employ time-multiplexed pilots and data. The superiority in the DL SINR performance of the channel estimator based on superimposed pilots and the higher throughput of the hybrid system are demonstrated by means of simulations.

Connected through hyperedge HE-1 (induced by source paper "covariance matrix estimation for massive mimo"):
  with members:
    - "massive mimo has unlimited capacity"
    - "superimposed pilots are superior for mitigating pilot contamination in massive mimo"
    - "massive mimo pilot decontamination and channel interpolation via wideband sparse channel estimation"
    - "massive mimo with imperfect channel covariance information"
    - "downlink performance of superimposed pilots in massive mimo systems"
    - "pilot contamination is not a fundamental asymptotic limitation in massive mimo"
    - "massive mimo for next generation wireless systems"
    - "blind pilot decontamination"

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)