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: "channel estimation for hybrid architecture based wideband millimeter wave systems"
  Abstract: Hybrid analog and digital precoding allows millimeter wave (mmWave) systems to achieve both array and multiplexing gain. The design of the hybrid precoders and combiners, though, is usually based on knowledge of the channel. Prior work on mmWave channel estimation with hybrid architectures focused on narrowband channels. Since mmWave systems will be wideband with frequency selectivity, it is vital to develop channel estimation solutions for hybrid architectures based wideband mmWave systems. In this paper, we develop a sparse formulation and compressed sensing based solutions for the wideband mmWave channel estimation problem for hybrid architectures. First, we leverage the sparse structure of the frequency selective mmWave channels and formulate the channel estimation problem as a sparse recovery in both time and frequency domains. Then, we propose explicit channel estimation techniques for purely time or frequency domains and for combined time/frequency domains. Our solutions are suitable for both SC-FDE and OFDM systems. Simulation results show that the proposed solutions achieve good channel estimation quality, while requiring small training overhead. Leveraging the hybrid architecture at the transceivers gives further improvement in estimation error performance and achievable rates.

Connected through hyperedge HE-1 (induced by source paper "multiple antenna technologies for beyond 5g"):
  with members:
    - "intelligent reflecting surface versus decode and forward how large surfaces are needed to beat relaying"
    - "robust trajectory and resource allocation design for secure uav aided communications"
    - "a new look at cell free massive mimo making it practical with dynamic cooperation"
    - "scalability aspects of cell free massive mimo"
    - "cascaded channel estimation for large intelligent metasurface assisted massive mimo"
    - "robust and secure wireless communications via intelligent reflecting surfaces"
    - "channel estimation for intelligent reflecting surface assisted multiuser communications framework algorithms and analysis"
    - "resource allocation for secure irs assisted multiuser miso systems"

Connected through hyperedge HE-2 (induced by source paper "generalized approximate message passing for massive mimo mmwave channel estimation with laplacian prior"):
  with members:
    - "sparse activity detection for massive connectivity"
    - "a lse and sparse message passing based channel estimation for mmwave mimo systems"
    - "bayes optimal joint channel and data estimation for massive mimo with low precision adcs"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "convergence analysis and assurance for gaussian message passing iterative detector in massive mu mimo systems"
    - "low rank tensor decomposition aided channel estimation for millimeter wave mimo ofdm systems"
    - "iterative channel estimation using lse and sparse message passing for mmwave mimo systems"
    - "channel estimation in broadband millimeter wave mimo systems with few bit adcs"

Connected through hyperedge HE-3 (induced by source paper "periodic analog channel estimation aided beamforming for massive mimo systems"):
  with members:
    - "hybrid beamforming with selection for multiuser massive mimo systems"
    - "fast analog beam tracking in phased antenna arrays theory and performance"
    - "omnidirectional precoding and combining based synchronization for millimeter wave massive mimo systems"
    - "design and analysis of initial access in millimeter wave cellular networks"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "initial access in 5g mmwave cellular networks"
    - "timing and carrier synchronization in wireless communication systems a survey and classification of research in the last 5 years"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"

Connected through hyperedge HE-4 (induced by source paper "beam squint and channel estimation for wideband mmwave massive mimo ofdm systems"):
  with members:
    - "spatial and frequency wideband effects in millimeter wave massive mimo systems"
    - "beamforming codebook compensation for beam squint with channel capacity constraint"
    - "a new view of multi user hybrid massive mimo non orthogonal angle division multiple access"
    - "multi user precoding and channel estimation for hybrid millimeter wave systems"
    - "millimeter wave channel estimation via exploiting joint sparse and low rank structures"
    - "effect of wideband beam squint on codebook design in phased array wireless systems"
    - "channel estimation for millimeter wave multiuser mimo systems via parafac decomposition"
    - "low rank tensor decomposition aided channel estimation for millimeter wave mimo ofdm systems"

Connected through hyperedge HE-5 (induced by source paper "fully partially connected hybrid beamforming architectures for mmwave mu mimo"):
  with members:
    - "hybrid precoding architecture for massive multiuser mimo with dissipation sub connected or fully connected structures"
    - "on the energy efficiency of mimo hybrid beamforming for millimeter wave systems with nonlinear power amplifiers"
    - "hybrid beamforming based on implicit channel state information for millimeter wave links"
    - "fully connected vs sub connected hybrid precoding architectures for mmwave mu mimo"
    - "millimeter wave mimo prototype measurements and experimental results"
    - "hybrid analog digital beamforming for massive mimo systems"
    - "frequency domain compressive channel estimation for frequency selective hybrid mmwave mimo systems"
    - "a robust time domain beam alignment scheme for multi user wideband mmwave systems"

Connected through hyperedge HE-6 (induced by source paper "optimal channel estimation for hybrid energy beamforming under phase shifter impairments"):
  with members:
    - "sensitive and nonlinear far field rf energy harvesting in wireless communications"
    - "wireless energy beamforming using received signal strength indicator feedback"
    - "multiuser millimeter wave beamforming strategies with quantized and statistical csit"
    - "on the feasibility of wireless energy transfer using massive antenna arrays"
    - "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"
    - "i q imbalance aware widely linear receiver for uplink multi cell massive mimo systems design and sum rate analysis"
    - "massive mimo ten myths and one critical question"

Connected through hyperedge HE-7 (induced by source paper "closed loop sparse channel estimation for wideband millimeter wave full dimensional mimo systems"):
  with members:
    - "wideband hybrid precoding for next generation backhaul fronthaul based on mmwave fd mimo"
    - "over sampling codebook based hybrid minimum sum mean square error precoding for millimeter wave 3d mimo"
    - "stochastic successive convex optimization for two timescale hybrid precoding in massive mimo"
    - "multi user precoding and channel estimation for hybrid millimeter wave systems"
    - "compressive sensing techniques for next generation wireless communications"
    - "millimeter wave mimo channel estimation using overlapped beam patterns and rate adaptation"
    - "channel estimation for millimeter wave multiuser mimo systems via parafac decomposition"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"

Connected through hyperedge HE-8 (induced by source paper "compressed sensing channel estimation for ofdm with non gaussian multipath gains"):
  with members:
    - "fast channel estimation for millimetre wave wireless systems using overlapped beam patterns"
    - "average performance of orthogonal matching pursuit omp for sparse approximation"
    - "compressive channel estimation and tracking for large arrays in mm wave picocells"
    - "channel estimation for millimeter wave massive mimo with hybrid precoding over frequency selective fading channels"
    - "compressed sensing algorithms for ofdm channel estimation"
    - "channel estimation in broadband millimeter wave mimo systems with few bit adcs"
    - "limited feedback hybrid precoding for multi user millimeter wave systems"
    - "distributed compressive csit estimation and feedback for fdd multi user massive 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)