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: "adaptive millimeter wave beam alignment for dual polarized mimo systems"
  Abstract: Fifth generation wireless systems are expected to employ multiple antenna communication at millimeter wave (mmWave) frequencies using small cells within heterogeneous cellular networks. The high path loss of mmWave as well as physical obstructions make communication challenging. To compensate for the severe path loss, mmWave systems may employ a beam alignment algorithm that facilitates highly directional transmission by aligning the beam direction of multiple antenna arrays. This paper discusses a mmWave system employing dual-polarized antennas. First, we propose a practical soft-decision beam alignment (soft-alignment) algorithm that exploits orthogonal polarizations. By sounding the orthogonal polarizations in parallel, the equality criterion of the Welch bound for training sequences is relaxed. Second, the analog beamforming system is adapted to the directional characteristics of the mmWave link assuming a high Ricean K-factor and poor scattering environment. The soft-algorithm enables the mmWave system to align innumerable narrow beams to channel subspace in an attempt to effectively scan the mmWave channel. Thirds, we propose a method to efficiently adapt the number of channel sounding observations to the specific channel environment based on an approximate probability of beam misalignment. Simulation results show the proposed soft-alignment algorithm with adaptive sounding time effectively scans the channel subspace of a mobile user by exploiting polarization diversity.

Connected through hyperedge HE-1 (induced by source paper "fast beam alignment for millimeter wave communications a sparse encoding and phaseless decoding approach"):
  with members:
    - "efficient beam alignment for mmwave single carrier systems with hybrid mimo transceivers"
    - "millimeter wave channel estimation via exploiting joint sparse and low rank structures"
    - "compressive channel estimation and tracking for large arrays in mm wave picocells"
    - "channel estimation for millimeter wave multiuser mimo systems via parafac decomposition"
    - "low rf complexity technologies to enable millimeter wave mimo with large antenna array for 5g wireless communications"
    - "low rank tensor decomposition aided channel estimation for millimeter wave mimo ofdm systems"
    - "spatially common sparsity based adaptive channel estimation and feedback for fdd massive mimo"
    - "channel estimation and hybrid precoding for millimeter wave cellular systems"

Connected through hyperedge HE-2 (induced by source paper "two dimensional aod and aoa acquisition for wideband millimeter wave systems with dual polarized mimo"):
  with members:
    - "channel estimation for millimeter wave massive mimo with hybrid precoding over frequency selective fading channels"
    - "an overview of signal processing techniques for millimeter wave mimo systems"
    - "channel estimation for hybrid architecture based wideband millimeter wave systems"
    - "auxiliary beam pair enabled aod and aoa estimation in closed loop large scale mmwave mimo systems"
    - "low rank tensor decomposition aided channel estimation for millimeter wave mimo ofdm systems"
    - "frequency selective hybrid precoding for limited feedback millimeter wave systems"
    - "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 "enclosed mmwave wearable networks feasibility and performance"):
  with members:
    - "device to device millimeter wave communications interference coverage rate and finite topologies"
    - "an analytical framework for device to device communication in cellular networks"
    - "analysis of millimeter wave networked wearables in crowded environments"
    - "a survey of millimeter wave mmwave communications for 5g opportunities and challenges"
    - "the human body and millimeter wave wireless communication systems interactions and implications"
    - "coverage and rate analysis for millimeter wave cellular networks"
    - "what will 5g be"
    - "five disruptive technology directions for 5g"

Connected through hyperedge HE-4 (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"
    - "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"
    - "optimization of training and feedback overhead for beamforming over block fading channels"

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)