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 "subspace tracking and least squares approaches to channel estimation in millimeter wave multiuser mimo"):
  Abstract: The problem of MIMO channel estimation at millimeter wave (mmWave) frequencies, both in a single-user and in a multi-user setting, is tackled in this paper. Using a subspace approach, we develop a protocol enabling the estimation of the right (resp. left) singular vectors at the transmitter (resp. receiver) side; then, we adapt the projection approximation subspace tracking with deflation (PASTd) and the orthogonal Oja (OOJA) algorithms to our framework and obtain two channel estimation algorithms. We also present an alternative algorithm based on the least squares (LS) approach. The hybrid analog/digital nature of the beamformer is also explicitly taken into account at the algorithm design stage. Our results clearly show that the proposed algorithms are very effective in estimating the principal directions of the MIMO channel matrix, and that they compare favorably, in terms of the performance-complexity trade-off, with respect to several competing alternatives.

Includes members:
  Member "massive mimo in sub 6 ghz and mmwave physical practical and use case differences":
    also connected through other hyperedges:
      - Hyperedge HE-1 (induced by source paper "real time implementation aspects of large intelligent surfaces")
  Member "cell free and user centric massive mimo at millimeter wave frequencies":
    also connected through other hyperedges:
      - Hyperedge HE-2 (induced by source paper "user centric 5g cellular networks resource allocation and comparison with the cell free massive mimo approach")
  Member "subspace tracking algorithms for millimeter wave mimo channel estimation with hybrid beamforming":
    also connected through other hyperedges:
      - Hyperedge HE-3 (induced by source paper "multiuser millimeter wave mimo channel estimation with hybrid beamforming")
  Member "millimeter wave mimo channel estimation using overlapped beam patterns and rate adaptation":
    also connected through other hyperedges:
      - Hyperedge HE-4 (induced by source paper "secure communication for spatially sparse millimeter wave massive mimo channels via hybrid precoding")
  Member "low complexity massive mimo subspace estimation and tracking from low dimensional projections":
    also connected through other hyperedges:
      - Hyperedge HE-5 (induced by source paper "an efficient beam and channel acquisition via sparsity map and joint angle delay power profile estimation for wideband massive mimo systems")
  Member "enhancing the estimation of mm wave large array channels by exploiting spatio temporal correlation and sparse scattering":
    also connected through other hyperedges:
      - Hyperedge HE-6 (induced by source paper "an efficient beam and channel acquisition via sparsity map and joint angle delay power profile estimation for wideband massive mimo systems")
  Member "an overview of signal processing techniques for millimeter wave mimo systems":
    also connected through other hyperedges:
      - Hyperedge HE-7 (induced by source paper "energy efficient hybrid precoding design for integrated multicast unicast millimeter wave communications with swipt")
  Member "subspace estimation and decomposition for large millimeter wave mimo systems":
    also connected through other hyperedges:
      - Hyperedge HE-8 (induced by source paper "a hybrid model based and data driven approach to spectrum sharing in mmwave cellular networks")

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)