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: "multi pair amplify and forward relaying with very large antenna arrays"
  Abstract: We consider a multi-pair relay channel where multiple sources simultaneously communicate with destinations using a relay. Each source or destination has only a single antenna, while the relay is equipped with a very large antenna array. We investigate the power efficiency of this system when maximum ratio combining/maximal ratio transmission (MRC/MRT) or zero-forcing (ZF) processing is used at the relay. Using a very large array, the transmit power of each source or relay (or both) can be made inversely proportional to the number of relay antennas while maintaining a given quality-of-service. At the same time, the achievable sum rate can be increased by a factor of the number of source-destination pairs. We show that when the number of antennas grows to infinity, the asymptotic achievable rates of MRC/MRT and ZF are the same if we scale the power at the sources. Depending on the large scale fading effect, MRC/MRT can outperform ZF or vice versa if we scale the power at the relay.

Connected through hyperedge HE-1 (induced by source paper "hybrid processing design for multipair massive mimo relaying with channel spatial correlation"):
  with members:
    - "secure massive mimo systems with limited rf chains"
    - "spectral and energy efficiency of multi pair massive mimo relay network with hybrid processing"
    - "framework of channel estimation for hybrid analog and digital processing enabled massive mimo communications"
    - "massive mimo with imperfect channel covariance information"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "channel covariance estimation in massive mimo frequency division duplex systems"
    - "hybrid beamforming for massive mimo a survey"
    - "hybrid mimo architectures for millimeter wave communications phase shifters or switches"

Connected through hyperedge HE-2 (induced by source paper "rate splitting robustness in multi pair massive mimo relay systems"):
  with members:
    - "mitigation of phase noise in massive mimo systems a rate splitting approach"
    - "rate splitting to mitigate residual transceiver hardware impairments in massive mimo systems"
    - "sum rate maximization for linearly precoded downlink multiuser miso systems with partial csit a rate splitting approach"
    - "rate splitting for mimo wireless networks a promising phy layer strategy for lte evolution"
    - "a rate splitting strategy for massive mimo with imperfect csit"
    - "hardware impairments aware transceiver for full duplex massive mimo relaying"
    - "rate analysis of two receiver miso broadcast channel with finite rate feedback a rate splitting approach"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"

Connected through hyperedge HE-3 (induced by source paper "energy efficient downlink transmission for multicell massive das with pilot contamination"):
  with members:
    - "joint power allocation and user association optimization for massive mimo systems"
    - "asymptotic orthogonality analysis of time domain sparse massive mimo channels"
    - "interference management in 5g reverse tdd hetnets with wireless backhaul a large system analysis"
    - "large scale mimo relaying techniques for physical layer security af or df"
    - "large system analysis of cognitive radio network via partially projected regularized zero forcing precoding"
    - "joint power and antenna selection optimization in large cloud radio access networks"
    - "impact of transceiver power consumption on the energy efficiency of zero forcing detector in massive mimo systems"
    - "massive mimo for next generation wireless systems"

Connected through hyperedge HE-4 (induced by source paper "spectral and energy efficiency of multi pair massive mimo relay network with hybrid processing"):
  with members:
    - "secure massive mimo systems with limited rf chains"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "on the number of rf chains and phase shifters and scheduling design with hybrid analog digital beamforming"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"
    - "near optimal hybrid processing for massive mimo systems via matrix decomposition"
    - "hybrid block diagonalization for massive multiuser mimo systems"
    - "multipair full duplex relaying with massive arrays and linear processing"

Connected through hyperedge HE-5 (induced by source paper "multipair massive mimo relaying with pilot data transmission overlay"):
  with members:
    - "energy efficient power control a look at 5g wireless technologies"
    - "massive mimo ten myths and one critical question"
    - "full duplex relaying in mimo ofdm frequency selective channels with optimal adaptive filtering"
    - "massive mimo full duplex relaying with optimal power allocation for independent multipairs"
    - "power allocation for multi pair massive mimo two way af relaying with linear processing"
    - "pilot reuse for massive mimo transmission over spatially correlated rayleigh fading channels"
    - "multipair full duplex relaying with massive arrays and linear processing"
    - "massive mimo for next generation wireless systems"

Connected through hyperedge HE-6 (induced by source paper "performance analysis for training based multi pair two way full duplex relaying with massive antennas"):
  with members:
    - "joint beamforming optimization and power control for full duplex mimo two way relay channel"
    - "massive mimo with non ideal arbitrary arrays hardware scaling laws and circuit aware design"
    - "multipair full duplex relaying with massive arrays and linear processing"
    - "massive mimo multicasting in noncooperative cellular networks"
    - "hybrid full half duplex system analysis in heterogeneous wireless networks"
    - "massive mimo for next generation wireless systems"
    - "full duplex cooperative cognitive radio with transmit imperfections"
    - "in band full duplex wireless challenges and opportunities"

Connected through hyperedge HE-7 (induced by source paper "multipair two way half duplex relaying with massive arrays and imperfect csi"):
  with members:
    - "performance analysis and scaling law of mrc mrt relaying with csi error in massive mimo systems"
    - "multipair full duplex relaying with massive arrays and linear processing"
    - "massive mimo with optimal power and training duration allocation"
    - "massive mimo for next generation wireless systems"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "relay selection and resource allocation for two way df af cognitive radio networks"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "optimal beamforming for two way multi antenna relay channel with analogue network coding"

Connected through hyperedge HE-8 (induced by source paper "performance analysis and scaling law of mrc mrt relaying with csi error in massive mimo systems"):
  with members:
    - "massive mimo ten myths and one critical question"
    - "outage probability of dual hop multiple antenna af systems with linear processing in the presence of co channel interference"
    - "ergodic capacity comparison of different relay precoding schemes in dual hop af systems with co channel interference"
    - "scaling up mimo opportunities and challenges with very large arrays"
    - "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.IT(Information Theory)