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: "optimization of training and feedback overhead for beamforming over block fading channels"
  Abstract: We examine the capacity of beamforming over a single-user, multiantenna link taking into account the overhead due to channel estimation and limited feedback of channel state information. Multi-input-single-output (MISO) and multi-input-multi-output (MIMO) channels are considered subject to block Rayleigh fading. Each coherence block contains L symbols, and is spanned by T training symbols, B feedback bits, and the data symbols. The training symbols are used to obtain a minimum mean squared error estimate of the channel matrix. Given this estimate, the receiver selects a transmit beamforming vector from a codebook containing 2B i.i.d. random vectors, and sends the corresponding B bits back to the transmitter. We derive bounds on the beamforming capacity for MISO and MIMO channels and characterize the optimal (rate-maximizing) training and feedback overhead (T and B) as L and the number of transmit antennas Nt both become large. The optimal Nt is limited by the coherence time, and increases as L/logL. For the MISO channel the optimal T/L and B/L (fractional overhead due to training and feedback) are asymptotically the same, and tend to zero at the rate 1/log Nt. For the MIMO channel the optimal feedback overhead B/L tends to zero faster (as 1/log2 Nt).

Connected through hyperedge HE-1 (induced by source paper "on optimizing feedback interval for temporally correlated mimo channels with transmit beamforming and finite rate feedback"):
  with members:
    - "on transmit beamforming for miso ofdm channels with finite rate feedback"
    - "training sequence design for feedback assisted hybrid beamforming in massive mimo systems"
    - "ensemble properties of rvq based limited feedback beamforming codebooks"
    - "tree structured random vector quantization for limited feedback wireless channels"
    - "on the minimum differential feedback for time correlated mimo rayleigh block fading channels"
    - "capacity of a multiple antenna fading channel with a quantized precoding matrix"
    - "limited feedback beamforming over temporally correlated channels"

Connected through hyperedge HE-2 (induced by source paper "a time variant channel prediction and feedback framework for interference alignment"):
  with members:
    - "on the degrees of freedom for opportunistic interference alignment with 1 bit feedback the 3 cell case"
    - "delay and doppler spreads of nonstationary vehicular channels for safety relevant scenarios"
    - "grassmannian differential limited feedback for interference alignment"
    - "adaptive interference alignment with csi uncertainty"
    - "ensemble properties of rvq based limited feedback beamforming codebooks"
    - "interference alignment with analog channel state feedback"
    - "interference alignment under limited feedback for mimo interference channels"
    - "multiuser mimo achievable rates with downlink training and channel state feedback"

Connected through hyperedge HE-3 (induced by source paper "on the miso channel with feedback can infinitely massive antennas achieve infinite capacity"):
  with members:
    - "achievable rates of fdd massive mimo systems with spatial channel correlation"
    - "what will 5g be"
    - "downlink training techniques for fdd massive mimo systems open loop and closed loop training with memory"
    - "energy and spectral efficiency of very large multiuser mimo systems"
    - "gaussian interference channel capacity to within one bit"
    - "multiuser mimo achievable rates with downlink training and channel state feedback"
    - "mimo broadcast channels with finite rate feedback"
    - "on the capacity of fading mimo broadcast channels with imperfect transmitter side information"

Connected through hyperedge HE-4 (induced by source paper "position aided large scale mimo channel estimation for high speed railway communication systems"):
  with members:
    - "differential modulation exploiting the spatial temporal correlation of wireless channels with moving antenna array"
    - "pilot contamination mitigation for wideband massive mmo number of cells vs multipath"
    - "massive mimo for next generation wireless systems"
    - "downlink training techniques for fdd massive mimo systems open loop and closed loop training with memory"
    - "qos distinguished achievable rate region for high speed railway wireless communications"
    - "compressive estimation of doubly selective channels in multicarrier systems leakage effects and sparsity enhancing processing"

Connected through hyperedge HE-5 (induced by source paper "common codebook millimeter wave beam design designing beams for both sounding and communication with uniform planar arrays"):
  with members:
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "adaptive millimeter wave beam alignment for dual polarized mimo systems"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "millimeter wave channel modeling and cellular capacity evaluation"
    - "millimeter wave beamforming for wireless backhaul and access in small cell networks"

Connected through hyperedge HE-6 (induced by source paper "near maximum likelihood detector and channel estimator for uplink multiuser massive mimo systems with one bit adcs"):
  with members:
    - "bayes optimal joint channel and data estimation for massive mimo with low precision adcs"
    - "mixed adc massive mimo"
    - "low power analog to digital conversion in millimeter wave systems impact of resolution and bandwidth on performance"
    - "one bit massive mimo channel estimation and high order modulations"
    - "capacity analysis of one bit quantized mimo systems with transmitter channel state information"
    - "adaptive damping and mean removal for the generalized approximate message passing algorithm"
    - "impact of residual transmit rf impairments on training based mimo systems"
    - "quantized massive mu mimo ofdm uplink"

Connected through hyperedge HE-7 (induced by source paper "optimization of energy harvesting miso communication system with feedback"):
  with members:
    - "throughput maximization for the gaussian relay channel with energy harvesting constraints"
    - "broadcasting with an energy harvesting rechargeable transmitter"
    - "two hop communication with energy harvesting"
    - "optimal energy allocation for wireless communications with energy harvesting constraints"
    - "a general framework for the optimization of energy harvesting communication systems with battery imperfections"
    - "transmission with energy harvesting nodes in fading wireless channels optimal policies"
    - "optimal packet scheduling on an energy harvesting broadcast link"
    - "training and feedback optimization for multiuser mimo downlink"

Connected through hyperedge HE-8 (induced by source paper "training sequence design for feedback assisted hybrid beamforming in massive mimo systems"):
  with members:
    - "pilot signal design for massive mimo systems a received signal to noise ratio based approach"
    - "pilot beam pattern design for channel estimation in massive mimo systems"
    - "distributed compressive csit estimation and feedback for fdd multi user massive mimo systems"
    - "a new approach to user scheduling in massive multi user mimo broadcast channels"
    - "downlink training techniques for fdd massive mimo systems open loop and closed loop training with memory"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "noncoherent trellis coded quantization a practical limited feedback technique for massive mimo systems"
    - "joint spatial division and multiplexing opportunistic beamforming and user grouping"

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)