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: "enhancing coexistence in the unlicensed band with massive mimo"
  Abstract: We consider cellular base stations (BSs) equipped with a large number of antennas and operating in the unlicensed band. We denote such system as massive MIMO unlicensed (mMIMO-U). We design the key procedures required to guarantee coexistence between a cellular BS and nearby Wi-Fi devices. These include: neighboring Wi-Fi channel covariance estimation, allocation of spatial degrees of freedom for interference suppression, and enhanced channel sensing and data transmission phases. We evaluate the performance of the so-designed mMIMO-U, showing that it allows simultaneous cellular and Wi-Fi transmissions by keeping their mutual interference below the regulatory threshold. The same is not true for conventional listen-before-talk (LBT) operations. As a result, mMIMO-U boosts the aggregate cellular-plus-Wi-Fi data rate in the unlicensed band with respect to conventional LBT, exhibiting increasing gains as the number of BS antennas grows.

Connected through hyperedge HE-1 (induced by source paper "indoor massive mimo deployments for uniformly high wireless capacity"):
  with members:
    - "cell edge aware precoding for downlink massive mimo cellular networks"
    - "massive mimo unlicensed for high performance indoor networks"
    - "massive mimo unlicensed a new approach to dynamic spectrum access"
    - "uplink sounding reference signal coordination to combat pilot contamination in 5g massive mimo"
    - "cell free massive mimo versus small cells"
    - "a stochastic analysis of network mimo systems"
    - "operating massive mimo in unlicensed bands for enhanced coexistence and spatial reuse"
    - "towards 1 gbps ue in cellular systems understanding ultra dense small cell deployments"

Connected through hyperedge HE-2 (induced by source paper "massive mimo unlicensed for high performance indoor networks"):
  with members:
    - "cell edge aware precoding for downlink massive mimo cellular networks"
    - "massive mimo unlicensed a new approach to dynamic spectrum access"
    - "operating massive mimo in unlicensed bands for enhanced coexistence and spatial reuse"
    - "receive combining vs multi stream multiplexing in downlink systems with multi antenna users"

Connected through hyperedge HE-3 (induced by source paper "operating massive mimo in unlicensed bands for enhanced coexistence and spatial reuse"):
  with members:
    - "cell edge aware precoding for downlink massive mimo cellular networks"
    - "massive mimo with imperfect channel covariance information"
    - "coexistence of wi fi and heterogeneous small cell networks sharing unlicensed spectrum"
    - "linear precoding based on polynomial expansion large scale multi cell mimo systems"
    - "massive mimo for next generation wireless systems"
    - "massive mimo for maximal spectral efficiency how many users and pilots should be allocated"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "large system analysis of linear precoding in miso broadcast channels with confidential messages"

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)