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: "codebook design for millimeter wave channel estimation with hybrid precoding structure"
  Abstract: In this paper, we study hierarchical codebook design for channel estimation in millimeter-wave (mmWave) communications with a hybrid precoding structure. Due to the limited saturation power of mmWave power amplifier (PA), we take the per-antenna power constraint (PAPC) into consideration. We first propose a metric, i.e., generalized detection probability (GDP), to evaluate the quality of \emph{an arbitrary codeword}. This metric not only enables an optimization approach for mmWave codebook design, but also can be used to compare the performance of two different codewords/codebooks. To the best of our knowledge, GDP is the first metric particularly for mmWave codebook design for channel estimation. We then propose an approach to design a hierarchical codebook exploiting BeaM Widening with Multi-RF-chain Sub-array technique (BMW-MS). To obtain crucial parameters of BMW-MS, we provide two solutions, namely a low-complexity search (LCS) solution to optimize the GDP metric and a closed-form (CF) solution to pursue a flat beam pattern. Performance comparisons show that BMW-MS/LCS and BMW-MS/CF achieve very close performances, and they outperform the existing alternatives under the PAPC.

Connected through hyperedge HE-1 (induced by source paper "channel estimation and hybrid precoding for distributed phased arrays based mimo wireless communications"):
  with members:
    - "modeling and analyzing millimeter wave cellular systems"
    - "framework of channel estimation for hybrid analog and digital processing enabled massive mimo communications"
    - "5g cellular user equipment from theory to practical hardware design"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "the world s first real time testbed for massive mimo design implementation and validation"
    - "an overview of transmission theory and techniques of large scale antenna systems for 5g wireless communications"
    - "hybrid digital and analog beamforming design for large scale antenna arrays"

Connected through hyperedge HE-2 (induced by source paper "a new codebook design for analog beamforming in millimeter wave communication"):
  with members:
    - "investigating robustness and interpretability of link prediction via adversarial modifications"
    - "partition pruning parallelization aware pruning for deep neural networks"
    - "age of information in multiple sensing"
    - "on the age of information in erasure channels with feedback"
    - "generating user friendly explanations for loan denials using gans"
    - "hybrid precoder and combiner design with low resolution phase shifters in mmwave mimo systems"
    - "embedding multimodal relational data for knowledge base completion"
    - "on the performance of mrc receiver with unknown timing mismatch a large scale analysis"

Connected through hyperedge HE-3 (induced by source paper "optimal link scheduling in millimeter wave multi hop networks with mu mimo radios"):
  with members:
    - "integrated access and backhaul in 5g mmwave networks potentials and challenges"
    - "distributed path selection strategies for integrated access and backhaul at mmwaves"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "understanding noise and interference regimes in 5g millimeter wave cellular networks"
    - "hybrid architectures with few bit adc receivers achievable rates and energy rate tradeoffs"
    - "towards an appropriate receiver beamforming scheme for millimeter wave communication a power consumption based comparison"
    - "massive mimo ten myths and one critical question"
    - "low power analog to digital conversion in millimeter wave systems impact of resolution and bandwidth on performance"

Connected through hyperedge HE-4 (induced by source paper "beam codebook design for 5g mmwave terminals"):
  with members:
    - "statistical blockage modeling and robustness of beamforming in millimeter wave systems"
    - "over sampling codebook based hybrid minimum sum mean square error precoding for millimeter wave 3d mimo"
    - "millimeter wave mimo prototype measurements and experimental results"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "beamforming tradeoffs for initial ue discovery in millimeter wave mimo systems"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"
    - "what will 5g be"
    - "designing unimodular codes via quadratic optimization"

Connected through hyperedge HE-5 (induced by source paper "beamforming learning for mmwave communication theory and experimental validation"):
  with members:
    - "path loss beamforming gain and time dynamics measurements at 28 ghz for 90 indoor coverage"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "spatially sparse precoding in millimeter wave mimo systems"

Connected through hyperedge HE-6 (induced by source paper "matrix completion based channel estimation for mmwave communication systems with array inherent impairments"):
  with members:
    - "millimeter wave channel estimation via exploiting joint sparse and low rank structures"
    - "alternating minimization algorithms for hybrid precoding in millimeter wave mimo systems"
    - "channel estimation for millimeter wave multiuser mimo systems via parafac decomposition"
    - "channel estimation for hybrid architecture based wideband millimeter wave systems"
    - "subspace estimation and decomposition for large millimeter wave mimo systems"
    - "channel estimation for mmwave massive mimo based access and backhaul in ultra dense network"
    - "joint csit acquisition based on low rank matrix completion for fdd massive mimo systems"
    - "hybrid analog digital channel estimation and beamforming training throughput tradeoff"

Connected through hyperedge HE-7 (induced by source paper "explore and eliminate optimized two stage search for millimeter wave beam alignment"):
  with members:
    - "hybrid beamforming where should the analog power amplifiers be placed"
    - "millimeter wave beam alignment large deviations analysis and design insights"
    - "millimeter wave mimo channel estimation using overlapped beam patterns and rate adaptation"
    - "inverse multipath fingerprinting for millimeter wave v2i beam alignment"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "millimeter wave vehicular communication to support massive automotive sensing"
    - "28 ghz millimeter wave ultrawideband small scale fading models in wireless channels"
    - "directional cell discovery in millimeter wave cellular networks"

Connected through hyperedge HE-8 (induced by source paper "user fairness non orthogonal multiple access noma for 5g millimeter wave communications with analog beamforming"):
  with members:
    - "optimal user scheduling and power allocation for millimeter wave noma systems"
    - "joint power allocation and beamforming for non orthogonal multiple access noma in 5g millimeter wave communications"
    - "a survey on non orthogonal multiple access for 5g networks research challenges and future trends"
    - "joint power control and beamforming for uplink non orthogonal multiple access in 5g millimeter wave communications"
    - "hierarchical codebook design for beamforming training in millimeter wave communication"
    - "on the number of rf chains and phase shifters and scheduling design with hybrid analog digital beamforming"
    - "fairness for non orthogonal multiple access in 5g systems"
    - "channel estimation and hybrid precoding for millimeter wave cellular 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)