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: "operating massive mimo in unlicensed bands for enhanced coexistence and spatial reuse"
  Abstract: We propose to operate massive multiple-input multiple output (MIMO) cellular base stations (BSs) in unlicensed bands. We denote such system as massive MIMO unlicensed (mMIMO-U). We design the key procedures required at a cellular BS to guarantee coexistence with nearby Wi-Fi devices operating in the same band. In particular, spatial reuse is enhanced by actively suppressing interference towards neighboring Wi-Fi devices. Wi-Fi interference rejection is also performed during an enhanced listen-before-talk (LBT) phase. These operations enable Wi-Fi devices to access the channel as though no cellular BSs were transmitting, and vice versa. Under concurrent Wi-Fi and BS transmissions, the downlink rates attainable by cellular user equipment (UEs) are degraded by the Wi-Fi-generated interference. To mitigate this effect, we select a suitable set of UEs to be served in the unlicensed band accounting for a measure of the Wi-Fi/UE proximity. Our results show that the so-designed mMIMO-U allows simultaneous cellular and Wi-Fi transmissions by keeping their mutual interference below the regulatory threshold. Compared to a system without interference suppression, Wi-Fi devices enjoy a median interference power reduction of between 3 dB with 16 antennas and 18 dB with 128 antennas. With mMIMO-U, cellular BSs can also achieve large data rates without significantly degrading the performance of Wi-Fi networks deployed within their coverage area.

Connected through hyperedge HE-1 (induced by source paper "cobeam beamforming based spectrum sharing with zero cross technology signaling for 5g wireless networks"):
  with members:
    - "massive mimo unlicensed a new approach to dynamic spectrum access"
    - "sharing of unlicensed spectrum by strategic operators"

Connected through hyperedge HE-2 (induced by source paper "understanding uav cellular communications from existing networks to massive mimo"):
  with members:
    - "cellular connected uav potentials challenges and promising technologies"
    - "supporting uav cellular communications through massive mimo"
    - "the essential guide to realizing 5g connected uavs with massive mimo"
    - "the sky is not the limit lte for unmanned aerial vehicles"
    - "a tutorial on uavs for wireless networks applications challenges and open problems"
    - "interference mitigation methods for unmanned aerial vehicles served by cellular networks"
    - "reshaping cellular networks for the sky the major factors and feasibility"
    - "massive mimo for communications with drone swarms"

Connected through hyperedge HE-3 (induced by source paper "supporting uav cellular communications through massive mimo"):
  with members:
    - "reshaping cellular networks for the sky the major factors and feasibility"
    - "massive mimo for communications with drone swarms"
    - "cell edge aware precoding for downlink massive mimo cellular networks"
    - "massive mimo unlicensed a new approach to dynamic spectrum access"
    - "uplink sounding reference signal coordination to combat pilot contamination in 5g massive mimo"
    - "a stochastic geometry model of backhaul and user coverage in urban uav networks"
    - "pilot contamination is not a fundamental asymptotic limitation in massive mimo"
    - "wireless communications with unmanned aerial vehicles opportunities and challenges"

Connected through hyperedge HE-4 (induced by source paper "distributing complexity a new approach to antenna selection for distributed massive mimo"):
  with members:
    - "massive mimo in real propagation environments do all antennas contribute equally"
    - "sub modularity and antenna selection in mimo systems"

Connected through hyperedge HE-5 (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"
    - "energy efficient design of mimo heterogeneous networks with wireless backhaul"
    - "a stochastic geometry framework for analyzing pairwise cooperative cellular networks"
    - "three practical aspects of massive mimo intermittent user activity pilot synchronism and asymmetric deployment"
    - "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-6 (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"
    - "enhancing coexistence in the unlicensed band with massive mimo"
    - "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"
    - "towards 1 gbps ue in cellular systems understanding ultra dense small cell deployments"

Connected through hyperedge HE-7 (induced by source paper "massive mimo unlicensed for high performance indoor networks"):
  with members:
    - "cell edge aware precoding for downlink massive mimo cellular networks"
    - "enhancing coexistence in the unlicensed band with massive mimo"
    - "massive mimo unlicensed a new approach to dynamic spectrum access"
    - "receive combining vs multi stream multiplexing in downlink systems with multi antenna users"

Connected through hyperedge HE-8 (induced by source paper "enhancing coexistence in the unlicensed band with massive mimo"):
  with members:
    - "coexistence of wi fi and heterogeneous small cell networks sharing unlicensed spectrum"
    - "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 correlated miso broadcast channels under limited feedback"

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)