human: Given a hyperedge-centered hypergraph: <hypergraph>, where the center hyperedge is induced by one source paper and its member nodes are the cited papers.

Details of the hypergraph:
Center hyperedge (induced by source paper "principal component analysis based broadband hybrid precoding for millimeter wave massive mimo systems"):
  Abstract: Hybrid analog-digital precoding is challenging for broadband millimeter-wave (mmWave) massive MIMO systems, since the analog precoder is frequency-flat but the mmWave channels are frequency-selective. In this paper, we propose a principal component analysis (PCA)-based broadband hybrid precoder/combiner design, where both the fully-connected array and partially-connected subarray (including the fixed and adaptive subarrays) are investigated. Specifically, we first design the hybrid precoder/combiner for fully-connected array and fixed subarray based on PCA, whereby a low-dimensional frequency-flat precoder/combiner is acquired based on the optimal high-dimensional frequency-selective precoder/combiner. Meanwhile, the near-optimality of our proposed PCA approach is theoretically proven. Moreover, for the adaptive subarray, a low-complexity shared agglomerative hierarchical clustering algorithm is proposed to group the antennas for the further improvement of spectral efficiency (SE) performance. Besides, we theoretically prove that the proposed antenna grouping algorithm is only determined by the slow time-varying channel parameters in the large antenna limit. Simulation results demonstrate the superiority of the proposed solution over state-of-the-art schemes in SE, energy efficiency (EE), bit-error-rate performance, and the robustness to time-varying channels. Our work reveals that the EE advantage of adaptive subarray over fully-connected array is obvious for both active and passive antennas, but the EE advantage of fixed subarray only holds for passive antennas.

Includes members:
  Member "closed loop sparse channel estimation for wideband millimeter wave full dimensional mimo systems":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "gmd based hybrid beamforming for large reconfigurable intelligent surface assisted millimeter wave massive mimo")
  Member "periodic analog channel estimation aided beamforming for massive mimo systems":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "continuous analog channel estimation aided beamforming for massive mimo systems")
  Member "device to device communications enabled energy efficient multicast scheduling in mmwave small cells":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "energy efficient power control of train ground mmwave communication for high speed trains")
  Member "energy efficient multi user miso communication using low resolution large intelligent surfaces":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "mimo noma networks relying on reconfigurable intelligent surface a signal cancellation based design")
  Member "wideband hybrid precoding for next generation backhaul fronthaul based on mmwave fd mimo":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "closed loop sparse channel estimation for wideband millimeter wave full dimensional mimo systems")
  Member "hybrid beamforming with selection for multiuser massive mimo systems":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "periodic analog channel estimation aided beamforming for massive mimo systems")
  Member "massive mimo channel estimation for millimeter wave systems via matrix completion":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "continuous analog channel estimation aided beamforming for massive mimo systems")
  Member "stochastic successive convex optimization for two timescale hybrid precoding in massive mimo":
    also connected through other hyperedges:
      - Hyperedge HE-8 (induced by source paper "joint design of fronthauling and hybrid beamforming for downlink c ran systems")

Question: Please tell me which class the source paper 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)