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: "low complexity channel estimation for millimeter wave systems with hybrid a d antenna processing"
  Abstract: The availability of large bandwidth at millimeter wave (mmWave) frequencies is one of the major factors that rendered very high frequencies a promising candidate enabler for fifth generation (5G) mobile communication networks. To confront with the intrinsic characteristics of signal propagation at frequencies of tens of GHz and being able to achieve data rates of the order of gigabits per second, mmWave systems are expected to employ large antenna arrays that implement highly directional beamforming. In this paper, we consider mmWave wireless systems comprising of nodes equipped with large antenna arrays and being capable of performing hybrid analog and digital (A/D) processing. Intending at realizing channel-aware transmit and receive beamforming, we focus on designing low complexity compressed sensing channel estimation. In particular, by adopting a temporally correlated mmWave channel model, we present two compressed sensing algorithms that exploit the temporal correlation to reduce the complexity of sparse channel estimation, one being greedy and the other one being iterative. Our representative performance evaluation results offer useful insights on the interplay among some system and operation parameters, and the accuracy of channel estimation.

Connected through hyperedge HE-1 (induced by source paper "principal component analysis based broadband hybrid precoding for millimeter wave massive mimo systems"):
  with members:
    - "closed loop sparse channel estimation for wideband millimeter wave full dimensional mimo systems"
    - "periodic analog channel estimation aided beamforming for massive mimo systems"
    - "device to device communications enabled energy efficient multicast scheduling in mmwave small cells"
    - "energy efficient multi user miso communication using low resolution large intelligent surfaces"
    - "wideband hybrid precoding for next generation backhaul fronthaul based on mmwave fd mimo"
    - "hybrid beamforming with selection for multiuser massive mimo systems"
    - "massive mimo channel estimation for millimeter wave systems via matrix completion"
    - "stochastic successive convex optimization for two timescale hybrid precoding in massive mimo"

Connected through hyperedge HE-2 (induced by source paper "massive mimo channel estimation for millimeter wave systems via matrix completion"):
  with members:
    - "millimeter wave channel estimation via exploiting joint sparse and low rank structures"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "vector approximate message passing for the generalized linear model"
    - "hybrid beamforming for massive mimo a survey"
    - "hybrid mimo architectures for millimeter wave communications phase shifters or switches"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"

Connected through hyperedge HE-3 (induced by source paper "position aided beam alignment for millimeter wave backhaul systems with large phased arrays"):
  with members:
    - "compressive channel estimation and tracking for large arrays in mm wave picocells"
    - "beamforming tradeoffs for initial ue discovery in millimeter wave mimo systems"
    - "sensor assisted movement identification and prediction for beamformed 60 ghz links a report"
    - "5g wireless backhaul networks challenges and research advances"
    - "directional cell discovery in millimeter wave cellular networks"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "what will 5g be"
    - "five disruptive technology directions for 5g"

Connected through hyperedge HE-4 (induced by source paper "omnidirectional precoding and combining based synchronization for millimeter wave massive mimo systems"):
  with members:
    - "bdma for millimeter wave terahertz massive mimo transmission with per beam synchronization"
    - "omnidirectional space time block coding for common information broadcasting in massive mimo systems"
    - "beamforming tradeoffs for initial ue discovery in millimeter wave mimo systems"
    - "directional cell discovery in millimeter wave cellular networks"
    - "coverage and rate analysis for millimeter wave cellular networks"
    - "downlink training techniques for fdd massive mimo systems open loop and closed loop training with memory"
    - "spatially sparse precoding in millimeter wave mimo systems"
    - "millimeter wave mimo channel tracking systems"

Connected through hyperedge HE-5 (induced by source paper "auxiliary beam pair enabled aod and aoa estimation in closed loop large scale mmwave mimo systems"):
  with members:
    - "a lse and sparse message passing based channel estimation for mmwave mimo systems"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "frequency selective hybrid precoding for limited feedback millimeter wave systems"
    - "beamforming tradeoffs for initial ue discovery in millimeter wave mimo systems"
    - "near optimal hybrid analog and digital precoding for downlink mmwave massive mimo systems"
    - "hybrid analog digital channel estimation and beamforming training throughput tradeoff"
    - "energy efficient hybrid analog and digital precoding for mmwave mimo systems with large antenna arrays"
    - "hybrid mimo architectures for millimeter wave communications phase shifters or switches"

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)